NONLINEAR PHENOMENA IN HYDRAULIC SYSTEMS

Pneumatic lectures

ABSTRACT

Hydraulic systems include various non-linearities in

static and dynamic characteristics of their components.

Consequently, a variety of nonlinear phenomena occur

in the systems This paper deals with intrinsic

nonlinear dynamic behaviors of hydraulic systems.

KEYWORDS

Hydraulics, Nonlinear phenomena, Hard

self-excitation, Micro-stick-slip, Chaos

INTRODUCTION

Hydraulic systems consist of various elements: pumps,

actuators, control valves, accumulators, restrictors,

pipelines and the like, which include many types of

nonlinearity, such as pressure-flow characteristics in

control valves, dry friction acting on actuators and

moving parts of valves, collision of valves against

valve seats As a result, various types of nonlinear

phenomena arise caused by these non-linearities It is a

marked feature of nonlinear systems that global

behaviors are sometimes quite different from local

behaviors In such cases, results of linear analysis are

unavailable to estimate global nature of the system.

This paper focuses on the nonlinear phenomena

occurring in hydraulic systems, especially, “hard

self-excitation” [8] whose global stability drastically

changes from local one on the basis of the author’s

studies in the past [1]-[7].

HARD SELF-EXCITATION IN

ASYMMET-RICALLY UNDER-LAPPED SPOOL VALVE

[1],[2]

Spool valves are classified into three types, over-lap

valves, zero-lap valves and under-lap valves on the

basis of the relation of the land-width to the port-width.

They are used properly according to their applications.

Usually in spool valves, the supply side lap is equated

to the exhaust side lap, but the lap of the exhaust side is

often taken smaller than that of the supply side by error

in measurement in working or for stability purpose.

This type of spool valve is called ”asymmetrically

under-lapped spool valve” Abnormal oscillations

so-called “hard self-excitation” are excited in hydraulic

servo-systems using this type of spool valve shown in

demonstrated in Fig 2, which shows the relation

between soft self-excitation and hard self-excitation by bifurcation maps of amplitude and phase plane trajectories of oscillations, where λ is a related system

Fig 1 Servo-system using metrically lapped spool valve

asym-Fig 2 Types of self-excitation, bifurcation maps and phase trajectories

λ(= εe/εs = 0.047 (εs=0.75mm) and the supply pressure

is Ps = 9.5MPa As shown here, the transient

oscillatory responses (a), (b) and (c) settle down to an

initial equilibrium position for relatively small inputs.

This shows the neutral position is locally stable.

However, the response (d) for larger inputs beyond a

critical valve develops into a finite amplitude

oscillation This fact shows that the phenomenon is a

typical “hard self-excitation”[1].

Fig 4 indicates a local stability map of the neutral

position of the system, which is calculated from the

following stability criterion Eq (1) [2].

0 2

0

2 A aMA V B

b M b B

and A is the cross-sectional area of the actuator, B the

damping coefficient, Cx the leakage coefficient, M the

load mass, Q the flow rate of the valve and κ the bulk

modulus of oil.

The curve in Fig 4 shows the critical supply

pressure against asymmetry ratio Λ(=1−λ) According

to the map, the system using a symmetrical lapped

valve λ=1 (εs= εe) is locally stable for the supply

pressure Ps =5.9MPa But for the system using a spool valve with asymmetry lap ratio λ=0.047, the neutral position is stable.

Equivalent asymmetry ratio (Λ=1−λ) is gradually increases according to the increase of the spool amplitude after the valve begins to move by input disturbances, even though the system is stable at the

neutral position The pressure-flow coefficient b in Eq.

(1) drastically increases as shown in Fig 5 On the

other hand, the flow-gain a changes little As a result,

the system becomes unstable and the oscillation is excited This is the mechanism of the “hard self- excitation” Taking into consideration this hard self- excitation, the self-excited region is enlarged more than locally unstable region that is between a solid line and a dashed line as shown in Fig 6.

Fig 3 Responses of hydraulic

servo-system with asymmetrical spool valve for

different magnitude of step inputs

, 2 1 0 , 2

0 2 0 1

, 0 where

V V V d C e C b b

P

Q P

Q b x

Q a

=

= +

, P P P P

This paper dealt with the new developments of

pneumatics in the following areas:

• Pneumatic components

• Industry segment specialized applications

• Best before-sales and after-sales services

Servo control, Field-bus, valve terminal, modular

systems, dynamic simulation, database

INTRODUCTION

Pneumatics were first utilised at the beginning of the

fifties Fig 1 shows a device built in 1955, which was

fitted with single-acting aluminium die cast cylinders A

typical pneumatic system of that time was used in this

device; it consisted of cylinders and manually operated

valves An operator played the roll of a “logic controller”.

Fig 1 An early pneumatic system

Fig 2 A purely pneumatic sequence controller with 12

inputs and 12 outputs

Over the past 50 years, with the rapid developments in science and technologies, especially in automation, mechanical, electronic and computer technologies, pneumatics has been experiencing a quick expansion and development Take automation sequence controllers as an example, the first pneumatic control systems functioned via valves that were actuated by driven camshafts In the seventies many purely pneumatically actuated sequence controllers such as the QUICKSTEPPER (Fig 2), which consisted of several pneumatic logic elements, were used

in applications.

How is pneumatics applied in today’s modern world? I would like to focus on the new developments in pneumatics in the following areas:

• Pneumatic components

• Industry segment specialized applications

• Best before and after-sales services

NEW DEVELOPMENTS IN PNEUMATIC COMPONENTS

o The combination of different techniques The combining of pneumatics with electronics and of pneumatics with mechanics became an obvious trend over the last 10 years.

Behind this trend is the fact that more and more pneumatic drives, sensors and valves are used in a modern automatic machine This means more inputs and outputs are required in the control system A purely pneumatic

demands to improve the performance and to expand the

functions of pneumatic components A pneumatic valve

should be easy to install and fast switching A pneumatic

drive should be able to move faster and more precisely.

Sometimes an electro-pneumatic proportional valve is

required to convert a continuous electronic signal into

pneumatic signal.

All this resulted in the combination of pneumatics,

electronics and mechanics.

By combining pneumatics with mechanics, customers will

not only save engineering time with regard to designing

and testing, but also receive an optimised solution because

the product they receive is proven and tested by the

pneumatics manufacturer.

Fig 3 shows a swivelling/linear unit, in which a linear

cylinder is combined with a rotary drive to get

independent linear and rotational movements.

Fig 3 A swivelling/linear unit

Fig 4 shows pneumatic units used in an assembling

system This includes a linear and rotary cylinder

combined with a high precision guide unit Excellent

precision and rigidity can be achieved with this

combination of components.

The “valve terminal” concept was introduced at the

beginning of the nineties In recent years valve terminals

have been widely used The origin of such a product is to

meet the demands of the larger scale control system In a

valve terminal, the valves and electronic I/Os are

integrated in accordance with specific user interfaces (Fig.

5) Customers can order a valve terminal according to the

specification of their application They will get a complete

Fig 5 A valve terminal, the combination of pneumatics

and electronics

A valve terminal equipped with fieldbus connection makes it possible for the pneumatic system to be integrated as a part of a factory network.

Fig 7 is a multi controlled positioning system, a

pneumatic servo-positioning axis is combined with an

electrically driven axis In this system, we can see that

both the guided pneumatic linear cylinder DGPL and the

guided electrical axis DGEL have the same mechanical

interfaces This makes it much easier for customers to

design their machines.

Fig 6 Cylinder, solenoid valve, speed control valves

and sensors in an integrated unit

Fig.7 Pneumatic and electrical drives with the same

mechanical interface

o Compact performance

In many applications, a pneumatic control valve is to be

mounted together with some moving parts of the machine.

In this case, the valve should be as light and as small as

possible On the other hand, in order to shorten machine

the same flow rate (400 l/min) but the new generation of solenoid valve is only 10 mm in width, while the old type

is 40 mm.

Fig.8 In comparison, valves of 1961 and 1997, the same flow rate, but a quarter of the width

o More intelligence is integrated into products.

Faster movement is often desired on a machine It is not difficult to get a cylinder to move faster But it is more difficult to stop a fast moving cylinder properly (without vibrations or shocks).

Fig 9 shows a soft-stop cylinder, in which a displacement sensor, a 5/3 dynamic proportional valve and a smart controller are included With such a system, the time taken for the cylinder to travel from one end position to the other can be reduced by 30% In addition, 2 freely selectable intermediate position settings are possible.

Fig.9 Fast speed and soft stop

Fig.10 Smart pneumatic positioning axes

The controller is robust and suitable for industrial

applications Built-in intelligence enables it to find the

optimised control parameters The user needs only to

input the essential application data, such as the load,

stroke, diameter and so on Or even more simply, in the

case of the SPC11 controller, just to push a “teach-in”

button.

o Cutting costs with the modular product concept

In a modern highly automated machine, the control

system often has many functions One solution is to make

such products, in which all the necessary functions are

integrated, but this may incur high manufacturing costs.

Fig 11 A modular valve terminal with 26 solenoid

valves and various electronic interfaces

A modular valve terminal is shown in Fig 11 Customers can configure or select the number and the size of the valves, the quantity of the electronic I/Os and so on.

Fig 12 and Fig 13 show modular vacuum components and modular air service unit respectively.

Fig.12 A modular vacuum system with freely

combinable suction cup holder, angle compensator, filter and suction cup

o Innovation, the new driving principle

A new single-acting pneumatic drive - fluidic muscle - is shown in Fig 14 It can output 10 times more force than a standard cylinder of equivalent diameter Fig 14 shows some applications of such a drive.

Fig 13 A modular air service unit with manual on-off

valve, compressed air filter and regulator,

lubricator, soft-start valve, distributor and

pressure switch

Fig 14 Fluidic muscle and some typical applications

It is well known that with a pneumatic cylinder it is very

difficult to achieve slow movement without the stick-slip

effect To overcome this disadvantage electrically driven

cylinders of the same size and with the same installation

interfaces as standard pneumatic cylinders have been

TRENDS REGARDING APPLICATIONS

With regard to pneumatic applications, one of the most important tasks today is to develop more and more specialized products for the various industry segments.

Fig 15 Pneumatic components for the food and packing

industry

Fig 15 shows cylinders and valves that have been specially developed for the food and packaging industry, where high corrosion resistance and ease of cleaning are essential.

The electronics and handling and assembly industry also need pneumatic products that can meet special requirements Fig 4 shows some precisely guided pneumatic drives with very high rigidity that are suitable for use in the handling and assembling industry Fig 16 shows some miniature precisely guided pneumatic actuators that suit the applications in the electronics industry.

It is not enough nowadays just to offer customers a good

pneumatic product Customers need more and more help

with their everyday tasks This is because they get less

and less time for designing, establishing and maintaining

their machines.

A very efficient way is to help the customer by providing

new software tools.

An electronic catalogue using the database principle

makes it possible to access product information and

drawings quickly and easily, via function searching,

image searching and other searching methods (Fig 17).

Fig 18 shows a software tool ProPneu, which differs

from a normal dynamic simulation software tool ProPneu

can not only check an existing pneumatic system via

dynamic simulation but also automatically select the

components according to the performances required by

the customer The customer needs only provide Propneu

with a limited amount of information concerning an

application.

The settings and parameters of the components, such as

the setting of the pneumatic cushioning and the flow

control valves, can be automatically optimised by

Propneu, according to the criteria the user has selected.

Propneu can also recommend the appropriate pneumatic

components for a given task, e.g to move a defined load

in a required time and a certain distance vertically,

horizontally or any inclined installation.

Fig 19 shows the software FluidDraw that assists

customers in creating pneumatic circuits on a CAD

system If customers need to know whether their circuit

sequences are correct, then FluidSim is the right

simulation tool.

Fig 17 Fast product accessing via the electronic catalogue

Fig 18 ProPneu, an intelligent software for the selecting,

simulating and optimising of a pneumatic system

Fig 19 Software for designing and simulating circuits

for pneumatic sequences

Fig 20 3D CAD drawings on a Website

More and more engineers use a CAD system for

machine design, so, it is very helpful for them to get 2D

or 3D CAD drawings of the pneumatic components they

have selected As shown in Fig 20, they can now easily

import a 2D or 3D CAD drawing via the Internet.

[2] Stoll, Kurt, What is Pneumatics? Thesis, University

of Stuttgart, 1958

[3] Pneumatic Tips, No 51/1994, Festo Pneumatic, Esslingen

[4] Pneumatic World, 2000, No 1, 2

[5] Werner Deppert, Kurt Stoll, Cutting Costs with Pneumatics, 1988, ISBN 7-111-07456-4, in 14 Languages (including Chinese)

[6] Stefan Hesse, 99 Examples of Pneumatic Applications, 2000

[7] Hong Zhou, A Smart Pneumatic Servo Positioning Axis and Its Applications, 3rd JHPS, Proceedings of the Third JHPS International Symposium on Fluid Power, Yokohama, 1996

Xi’an Jiaotong University, 710049, Xi’an, P.R China

sawang@xjtu.edu.cn

ABSTRACT

As the precise model of most practical mechatronics

system cannot be obtained, the practice of typical

control method is limited Accordingly, numerous AI

(Artificial Intelligence) control methods have been used

widely Fuzzy control and Neural Network control have

been an important point in the developing process of the

field However, shortcomings exist in each of these

methods For example, the fuzzy control is unable to

learn, and the physical meanings of learning result of

the Neural Network control are not clear Combining the

strong points of above two methods, a new control

method of FNN (Fuzzy Neural Networks) is explored in

this paper Additionally, a problem concerning the

traditional network learning is discussed and a solution

to such a problem is obtained subsequently The new

control strategy does not depend on the classical model

and the algorithm is simple The results of the

experiments applying the new strategies are discussed.

Through different researches on control system, which

model is unacquainted, the reasonableness, effectiveness

and applying universality of the new control strategies is

proved.

INTRODUCTION

The mechatronics system becomes more and more

complicated According to the Incompatibility Principle

[1], the higher complicacy of the system is, the lower

ability to describe becomes So the typical control

methods based on the precise model cannot meet the

need AI offers new strategies for the mechatronics

control system.

Since the AI Project was launched at MIT in 1957, it

has achieved great success in many fields It attracts

more and more attention to AI and many AI methods

have been put forward [2] Fuzzy and NN (Neural

Networks) are important aspects in AI, simulating

different functions of the human brain The former

simulates the macroscopical functions, such as

syllogisms, but the latter simulates the associatron,

classification, memory by way of imitating the

microcosmic structure But the Fuzzy cannot learn and

the NN cannot deduce In addition, the Fuzzy can be

understood and the learning results of the NN cannot

[3] The new AI method, FNN , which integrated the good qualities of the two methods, has been the hotspot

in AI fields.

Firstly, this paper will discuss a new object function of FNN learning and a problem in NN control system Then a new FNN control structure will be put forward based on them Finally, some conclusions will be acquired, supported by related experiments.

THE OBJECT FUNCTION

Object function is very important for the control system.

∫e2

dt is usually taken as the Object function in time fields The smaller the area, like figure 1, which surrounded by the phase track in the phase space is, the better performance of the system is So the integrated object function can be defined as

de e dt e

(1) where e is the error between the sysytem’s real output

and the reference input e& is the differential coefficient

de de dt

de de

(2) ∫ e&de = ∫ e&2dt

(3) The area surounded by the phase track is the integration

of the error’s differential coefficient So the error and its differential coefficient are synthetically considered in the new object.

Fig 2 The typical structure of NN

Where y is the real output, r is the reference input,

u is the NN’s output, and e is the system error The

object of the control is made y=r, namely e becomes 0.

The learning method adopted is usually Gradient

Search Obviously, the error is the main parameter in

this method.

In theory, the error which is needed by the NN

learning is e’, defined as

o

u u

e = − (4) Where uo is the NN’s desired output uo can be

obtained:

) (1

r f

uo = − (5)

So the general object function can be defined as:

2 1)) ( ( u f r

Je∗= − −(6)

Then

w

r f r f u w

1 1

(7)

Because the precise model of the system can not be

obtained, even though the precise model is obtained,

most practical mechatonics system is very complex.

Therefore, the equations cannot be solved So uo is not

known Practically, y usually is used to replace uo, as a

result, the object function is defined as

2) ( r y

Je = − (8)

So

w

y y r w

Generally the following equation is not true.

w

r f r f u w

y y r

1 1

(10)

In fact, the signs are different from each other between

these at the two sides of the “=” So the NN can not

approach the desired value, even the NN’s astringency

of FNN can be put forward It looks like figure 3 Where the network NN1 is FNN network and NN2 is the RBF network W is the weight of NN1 and W’ is the weight of NN2 NN1 is employed to obtain the control output u NN2 is just as the system’s inverse model, it is used to acquire the uo, u’s desired output.

System f(u) u

e

e&

+ _

W

a

W' a'

NN1

NN2

the learning algorithm

u1 + _ adjust

adjust

e

e&

eu

Fig 3 The structure of the new FNN

There are lots of types of FNN, but generally they can

be classified two kinds One is the NN which directly is constructed by the Fuzzy’s rule,another is the NN which

is fuzzied from the unfuzzy NN.

In this paper, The FNN has two layers Its topical structure is achieved by the Fuzzy, and the fuzzy learning ability becomes strong by taking advantage of

NN The number of NN’s hidden layer’s nodes is just the same with that of the fuzzy’s section and the accept function of the nodes is corresponding to the membership function of the Fuzzy section.

So define the object function again:

∫ +

∫ +

The new algorithm’s detail process is the following:

(1) Partition the fuzzy section according to e and e&

(2) Initial the network (3) Calculate T

W

u = α * where α = ( a1£¬a2£¬ am) is the accept function m is the number of the nodes

(4) Modify the weight W and W’

For the j th node, because:

dt e grad dt

e grad J

grad

j j

dt e grad ∫

∗

W f r u f r y

r

T T

e = 1 − = ' α ' − α

T j T T

j

u

W W w

e

αα

α α

' (

j

u

W W w

e

' '

' ) '

' ( '

2

α α

α α

u f u f r w

α α

α

T j

u

u f u f

u u

y y r w

y y

) ( ) 1 ( ) (

k u k u

k y k y u

u

f

− +

− +

≅

∂

∂

t k u k u

k y k y k

y u

y

∆

∗

− +

− +

∗

− +

) 1 ( ) ( 2 ) 1 (

&

y r t

y r t

y t

k r k

r

t

− +

−

∆

− +

lim

0 0

t

∆ is the interval of sample time

)) ( 1 )

)

1

(

] ) ( ) 1 ( ) ( )

1

(

) ( )

1

(

* ) (

u

t

k y k y

k

y

t

k y k

y t

k r

k

r

k y k r k u k

u

k y k

y

k w

process for the NN1, and the damp of the system is increase, which is useful for the stability of the system This point is proved in the experiments.

(5) If J supplies the demand, then stop, else go to (3).

s s

2

10

* 1

1

* 975 4

* 975 4

* 041 0 2

975 4 )

+ +

+

= Its step response likes figure 4 The result that is used the new FNN control is also shown as figure 4.

Fig 4 The result of the physical emulational experiment

The result is obtained after six times learning Apparently it is better than that of PID and BP (The result of PID and BP is not given) It is found in the experiment that δ and β are very important for the result Motor is the typical mechatronics system, but its precise mathematics model cannot be obtained Regulating the motor’s speed is the normal work in the practice, and a lot of methods in such an aspect have been brought forward [4][5][6] Figure 5 is the result of the experiment about regulating the motor’s speed.

Fig 5 The result of the experiment about motor

Fig 6 The result of the PID control

The result of the new FNN is obtained after three times

learning Comparing the results of the experiments, the

strengths of the new FNN are outstanding In addition,

PID’s parameter is confirmed hardly The PID

optimized result shown in Fig.6, which is caused by

regulating again and again According to the

experiments, the availability of the new FNN proposed

above is proved.

SUMMARY AND OUTLOOK

At first, a new object function based on the phase space

is defined, then a problem about NN’s learning is

discussed and a new FNN control Strategies is

proposed, at last two related experiments are practised.

Through the experiments, some results can be obtained:

(1) The new FNN is available.

(2) The new FNN does not need the precise

mathematics model of the system.

(3) The new object function is valid.

(4) The new FNN is good for overcoming the problem

in NN control.

It is very easy for the control rules to be mined from the

New FNN There are some papers concerning this point

[7][8].

[1] Sugeno M, K Tanaka, A fuzzy-logic-based approach to qualitative modeling IEEE Trans on Fuzzy Systems, 1993, 1(1): 7-13.

[2] Daniel G.Bobrow, J.Michael Brady, Artificial Intelligence 40 years later, Artificial Intelligence, 1998, (103) 1∼4.

[3] Li Shaoyuan, Xi Yugeng, Chen Zengqiang, Yuan Zhuzhi, The new progresses in Intelligent Control (I), Control and Decision, 2000, 15(1): 1-5, (in Chinese) [4] N.C Sahoo, S.K Panda, P.K Dash, A current modulation scheme for direct torquecontrol of switched reluctance motor using fuzzy logic, Mechatronics ,

2000, 10 353 370.

[5] Ma Hongtao, Wei Zeding, Zhai Cheng, The new control system for alternating voltage adjusting and practice, Journal of Hebei Academy of Sciences, 1997 (1): 12-14, (in Chinese).

[6] Xiang Jun, Li Shiwne, A PLL Motor-Speed control system, Journal of South-West Jiaotong University,

1998, 33(6): 705-709, (in Chinese).

[7] Chen Ming, Wang Jing, Shen Li, Research on Automatic Fuzzy Rule Acquisition Based on Genetic Algorithms, Journal of Software, 2000,11(1): 85-90 (in Chinese).

[8] Hou Yuanhui, Lu Yuchang, Shi Chunyi, Using phase approach to extract knowledge from artificial neural network, Journal of Qinhua University, 1998, 38(9): 96-99, (in Chinese).

two-State Key Laboratory of Fluid Power, Zhejiang University, Hangzhou, Zhejiang, 310027,P.R.China

Xwkong@sfp.zju.edu.cn

ABSTRACT

The accurate mathematical model of valve control

hydraulic system with long pipeline is constructed

through theoretical analysis The influences of long

pipeline on valve control hydraulic system are

investigated A series of conclusions were obtained,

which are important to the design and analysis of valve

control hydraulic system.

INTRODUCTION

Large-sized construction machinery usually has tens of

actuators All of them get power from a central

hydraulic source Some are far away from the hydraulic

source The long pipeline between actuator and

hydraulic source is essential sometimes It causes many

problems to electro-hydraulic system This paper studies

the influences of long pipeline on valve control system

and comes to some simply and valuable conclusions.

TRANSFER FUNCTION OF VALVE

CONTROL SYSTEM

In order to analyze the characteristics of valve control

system with long pipeline, The transfer function of

valve control system must be established Fig.1 shows

the principle of valve control system with long pipeline

Fig.1 The principle of valve control system

(1) Pipe Dynamic Characteristics

Equation[2][4]





Γ+

Γ

=

Γ+

Γ

=

)()()(

1)())

(

)()()()()()

(

2 2

1

2 2

1

s sh s P s Z s ch s Q s

Q

s sh s Q s Z s ch s P s

P

C C

Assume that the hydraulic source supply constant

pressure oil, the return pressure is zero and the length of

in-line and return line is equal, then we obtain

0)))())

(

0)()()()()

(

0

=Γ+

Γ

s sh s Q s Z s ch

s

P

s sh s Q s Z s ch

s

P

v C v

sv C

)2()1(

where Γ (s ) —propagation operator

Zc(s ) characteristic impedance

(2) Four-way Slide valve Dynamic Equation

If orifice area of slide valve is matching and symmetric, then the flow-pressure equation is

ρ ρ

v f sv d v f sv d L

P P P A C P P P A C

v f sv d v f sv d v sv

P P P A C P P P A C Q

2 0 1

0

−++

=

W

A X W

A X X W A A

V

V V

10

10 10

1

,0,

A X X W A A

V

V V

20

20 20

2

,0,

C is the flow coefficient The Laplace transforms of

Eq (3) and Eq (4) are as follows

)6()()()()()(

)5())

()()()

0 0 0 0

s P K s P K s P K s X K s Q

s P K s P K s P K s X K s Q

v S sv SS f CS v QS sv

v sv

S f C v Q L

++

−

=

++

−

=

|

|(

20 10

P P P W

C

v f sv d

−+

)(

2

20 10

20 10

0 20 10

0 20 0

10

A A

A A

P P P A A C

P P P

A P

P P

A C

v f sv d

v f sv v f sv

|

|2

00,

|

|2

0,

)(

2

10 20 0

20

20 10 0

10

20 10 0

20 0

10

A A P

P P A C

A A P

P P A C

A A P P P

A P

v f sv d

v f sv v f

|

|

00

|

|

0)

(

10 20 0

20 10 0

20 10 0 0

A A P

P P W

C

A A P

P P W

C

A A P P P P P

v f sv d

v f sv v f

,

C S S C S

S

P

Q K K P

,

(3) The Continuity Equation and Force

Balance Equation of Cylinder

)8()(

)7()(

4

2 2

Equation Balance

Force

F X K dt

dX B dt X d m

P

A

Equation Continuity

P C dt

dP E

V dt

dX A

Q

L t t t t t t f

t

f sl f

y t t t

L

+++

=

⋅+

⋅+

=

where At and Xt are the area and motion of hydraulic

cylinder piston respectively, EY is the equivalent

volume elastic modulus, Vt is the general volume of

hydraulic cylinder, Csl is the general leakage

coefficient Eqs (1), (2), (5), (6) together with the

Laplace transforms of Eq (7) and Eq (8) composed a

set equations, from which we can obtain the transfer

function of system as follows

2 1

h h C h

ω

where

))(())(()(

1

s ch s sh Z s

t y h

V m

t y t

sl C h

m E

V A

B V

m E A

C K

4

) (

+ +

=

ξ

t

t y C t

CS h h

V

m E K A

K2 ' = ξ −

ξ

t

Q v

A

K K K K

=

THEORETICAL ANALYSIS OF THE INFLUENCES OF PIPE ON VALVE CONTROL HYDRAULIC SYSTEM

When the influence of pipe is neglected

s

sv P

P = =constant P0v= P0= 0 G1( s ) =0 The transfer function of system is

12)

(

2 2 '

++

=

=

•

s s

K X

X s G

h h h

v v

t

ω

ξ ω

The influences of pipe on system can be measured by the difference between G (s ) and '( )

||

)(

'

ω ω ω

ω

j G

j G j

G

and

|))(())((

|)

| ) 2

( 2 ) ( ω K G1 j ω

K

K K

characteristics of system The actual value of Kc and

cs

K aren’t zero but very small So, the influence of pipe

to system is minimal under the condition

It will be seen that if KC is small enough, the influences

of pipe on system can be neglected According to the

theory of fluid transmission lines, | G1( j ω ) | reaches

maximal point at resonance frequency and fluctuates

periodically as frequency ascends Accordingly, G ( j ω )

fluctuates periodically relating to G'( j ω ) The

fluctuation frequency is proportional to the length of

pipe The fluctuation amplitude descends as frequency

ascends.

SIMULATION STUDY

It will be seen that the influences of pipe on hydraulic

system are related to the steady-state point of slide

valve Slide valve is in zero position in position

control system and in nonzero position in velocity

control system The following is the simulation study

of them.

(1) Position Control System

The simulation parameters are as follows:

Fig.2 presents the frequency response characteristics of

valve control hydraulic system under different pipe

the fluctuation amplitude reaches maximum near the natural frequency of system and is smaller in low- frequency and high-frequency stage

The frequency response is generally approximate to second-order system.

Fig.2 The frequency response characteristic of system

when slide valve is in zero Position

Fig.3 The frequency response characteristic of system

when slide valve is in nonzero position

-180 -160 -140 -120 -100 -80 -60 -40 -20 0 Phase-frequency characteristics

10 2

Fig.3 presents the frequency response characteristics of

valve control hydraulic system under different pipe

length.

The simulation result shows:

the frequency response of system fluctuates

If the length of pipe or the value of KC isn’t small

enough, the system can’t be considered as

second-orde system.

CONCLUSION

This paper has presented an accurate mathematical

model for valve control hydraulic system with long

pipeline On the basis of the analysis to it, some

conclusions are reached.

1 The influences of pipe on system can be measured

approximately with the frequency domain criterion

| ) (

| ) 2

( 2

)

( ω K G1 j ω

K

K K

2 For given pipe parameters, Kc decides the influences

of pipe on system in terms of ideal zero lap slide

valve.

3 Pipe makes the frequency response of system

fluctuating periodically The fluctuation frequency is

proportional to the length of pipe The fluctuation

amplitude is decided by valve coefficient, pipe elastic

modulo and pipe inner diameter.

4 The influences of pipe are greater to velocity control

system than to position control system.

[8] Chen, Jine, “Theoretic solution of the transient flow

of liquid in the pipe with fluid Machinery”, Journal

of Hydrodynamics, v 4 n 4 Oct 1992 p 119-126

Institute of Mechatronic Control Engineering, Zhejiang University, and Hangzhou 310027 P.R.China

ABSTRACT

The flow-pressure relationship is an important external

characteristic of the pilot operated pressure relief valve.

Many research efforts have been put on this topic for its

significant impact on the overall hydraulic system.

Some of the researches focused on the influences of the

hydraulic bridge to the main stage, while the others

attempted to analyze the influence of difference pressure

measurement (direct or indirect) of the system pressure

using control theories In this project, a novel method

has been adopted The basic idea is to find out the

correlation between the pilot flow and the overflow of

the main valve, and use this relative function as a

criterion to compensate for the force bore on the valve

poppet The flow-pressure curve of the relief valve can

be bent upwards(under-compensated), flat, or

downwards(over- compensated) The above scheme has

been utilized in the manufacture’s product catalogs.

Key words: variable hydraulic resistance, force

compensating, relief valve, controllability

INTRODUCTION

In pilot operated pressure relief valve, the main valve is

actually controlled by the pilot hydraulic bridge On the

other hand, the pilot hydraulic circuit and the main

valve port hydraulic circuit form parallel hydraulic

network The current researches show that the

steady-state override pressure is related to the control pattern of

the pilot valve and varied with where the pressure

exerting on the pilot valve and where the pressure sign

coming from[1] This paper intends to find the

correlationship between the pilot flow and the main

overflow of the relief valve, and to control the

flow-pressure characteristic of the pilot operated flow-pressure

relief valve by compensating for the force bore on the

pilot poppet according to the correlationship.

THE CORRELATIONSHIP BETWEEN THE

PILOT FLOW AND THE MAIN

OVERFLOW OF THE RELIEF VALVE

Fig.1 shows the structure and the principle of the relief

valve with compensating for the force bore on the pilot

poppet And the flow equations and force equilibrium

equations under steady-state are described below.

Fig 1 The structure and principle of the relief valve with

compensating for force bore on the pilot poppet

Where c1= µ a1 11 ρ 2 , c3= µ a3 13 ρ 2 ; µ1, µ3are the flow coefficient of orifice r1 and r3 respectively,

ρ is fluid mass density, a11 and a13 are the cross-area

state point(q20 qx0 x0 y0) the increments equations

20

q

y b y

q b k p A p

2001221

q

q a y b k x c

2023022202

m qx A qx b x b x

3021002012

0

2= 2 − 2 + (15)

m q a k y c k y b22

20223023

The first part (m4) in right hand of formula (14) can be

omitted when compared with the others, so do the last

two parts in equations (15) and (16).Therefore, formula

(13) can be rewritten as follows:

Fig.2 The emulation curve of pilot flow varying with

the changing of the main overflow

a c A A c a A q

q

q a y b k x

+

≈

∆

3211223213

20

0

2023022202

THE COMPENSATING FOR THE FORCE BORE ON THE PILOT POPPET

The disadvantage of general relief valve is that the system pressure increases with the increasing of the overflow, and the higher the system pressure, the greater the override pressure (Fig.4 shows).

Fig.4 The experimental curve of the override pressure

changing with the overflow under different system pressure

According to the results above, the override pressure of the relief valve can be compensated by attaching

2

1

30 25 20 15 10

5

P1(Mpa)

qx(L/min))

q2(L/min))

200100

force, spring force, etc., when the main overflow varies.

Compensating force Fc :

Fc= p3a3 19

According to equation (2), the hydraulic resistance of

the pilot valve port under a steady-state point is as

follows[2]:

y b

p p q

a

2

322

=

∆

=

In order to discuss the general hydraulic resistance

property of the pilot valve port, the above equation can

q q

p p

R = ∆ − ∆ − ∆

0221020

a a q y

b k a q

y

b

y b k a

q

3 0 2 2 2 2 20 2

3 2 2 20 3

0 2 2 2 2

2

20

) 2

(

) ( 8 ) 2

(

2 4

Where the latter part of the numerator in the first

fraction can be omitted when compared with the former

part, the other parameters in formula (23) are positive,

therefore, the hydraulic resistance of the pilot valve port

decreases with the increasing of the pilot flow The

second part of the square bracket of the formula (23)

results from the compensating force, which results in

more reducing the hydraulic resistance of the pilot valve

port with the increasing of the pilot flow The greater

the parameter a3 or the smaller the parameter c3, the

greater the compensating force and the decreasing

amplitude of the pilot valve port hydraulic resistance.

From formulas (9) and (21), get:

Fig 5 The emulation curve of the compensating force varying with the changing of the pilot flow

THE CONTROLLABILITY OF THE FLOW-PRESSURE CHARACTERISTIC

OF THE RELIEF VALVE

Because the changing amplitude of the compensating force with the varying of the pilot flow is mainly dependent on the structural parameters a3 and c3

according to formula (24), it is reasonable to change the hydraulic resistance property which varies with the changing of pilot flow According to the formula (7)~(10) and (21):

∆ p1= λ ∆ Fc 25

) 2

(

2 2

) (

3 0 2 2 2 20 3 2

2 3 2 20 2 2 2 20 2 2 3 0 2 2 2 2 0 2

y b k q a c

c a q c a q c c y b k c c y k

+

− +

+ +

=

λ

26 From formula (25), it can be seen that different λ will

results in different characteristic of the control pressure p1 varying with the compensating force:

λ >0 p1 increases with the increasing of the compensating force, this is under-compensated

; λ =0 p1 keeps constant, and does not change with the compensating force, right-compensated;

λ <0 p1 decreases with the increasing of the compensating force, over-compensated.

Meanwhile, the value of λ is only dependent on the

structural parameters and pilot flow In formula (26), the value of denominator is positive, so, whether the value of λ is positive, zero or negative is decided by

the value of the numerator The first two parts of the numerator in the formula (26) can be omitted when compared with the others, so the value of λ is

mainly dependent on the last two parts , i.e.

a c a c2

1323

2 − >0 λ >0

a c a c2

1323

2 − =0 λ =0

a c a c2

1323

2 − <0 λ <0

Consequently, the value of λ is mainly dependent on

the arrangement of the parameters a2, a3, c1, c3, When the parameters a2 and c1 are fixed, the value of λ is

decided by a3 and c3 Fig.6 shows the theoretical relationship of the control pressure varying with the compensating force under different parameter value

Fig.6 The emulation curve of the control pressure

varying with the changing of the compensating force

From formulas (24) and (25):

c

a q

p1= ⋅ 2 202 3∆ 2

According to formulas (18) and (27), it can be seen that

the flow-pressure relationship of the relief valve is also

dependent on the value of λ , i.e there exists different

flow-pressure characteristic of the relief valve with

the different matching of the parameters a2, a3, c1, c3:

under-compensated, λ >0, the pressure increases with

the increasing of the overflow; right-compensated,

λ =0 the pressure

keeps constant, and does not change with overflow;

over-compensated, λ <0 the pressure decreases

with the increasing of the overflow.

EXPERIMENT ON FLOW-PRESSURE

CHARACTERISTIC OF THE RELIEF

VALVE

Fig.1 shows the structure of the experimental valve

(NG10), the relational structural parameters are as

Consequently, it is reasonable to obtain the pressure characteristic required according to the different parameters of the pilot hydraulic circuit Some kinds of pressure valves have been manufactured by applying the above principle by Roxroth Ltd Fig.8 shows one of the products, a pilot operated pressure relief valve[4].

flow-Fig.8 The structure and principle of the relief valve of

Roxroth Ltd.

CONCLUSIONS

(1) The pilot operated pressure valve is made up of parallel hydraulic network which formed by the hydraulic circuit of the pilot valve and that of the main valve port The pilot flow increases with the increasing

of the main overflow, and the greater the system pressure, the more the variation of the pilot flow varying with the overflow.

(2) The flow-pressure characteristic of the pilot operated pressure valve can be compensated by altering the equilibrium state of the force bore on the pilot poppet through attaching hydraulic resistance in the pilot poppet.

(3)There exists different flow-pressure characteristic with different compensating degree of the force bore on the pilot poppet: under-compensated, the flow- pressure curve will be bent upwards; right- compensated, kept flat; over-compensated, bent downwards.

(4) The principle of compensating the override pressure

of the relief valve by attaching a hydraulic resistance in

Fig.7 The experimental curves of the

flow-pressure characteristic of the relief valve

Chinese) Machine tool and hydraulics 1989(6):21~23

[2] Backé W, Zhu Wen Hydraulic resistance circuit

systemology, (in Chinese) Beijing: China

machinery press 1980

[4] Rexroth Induetrieventile und Zubehör RD00101/09.92, ss.165

Source English Français Deutsch

abrasion (f)

Usure, émoulage ou frottage de matériaux dans des éléments méca-niques

NOTE – Les produits de l’abrasion seront présents dans le système en temps que contamination particu-laire générée

Abrieb (m)

Abnutzen, abschleifen oder ben von Material an mechanischen Teilen

abscha-ANMERKUNG: Der Abrieb ist als erzeugte Feststoffverschmutzung in der Anlage vorhanden

Pressure using absolute vacuum as

a reference (See figures 1 and 2.)

pression (f) absolue

Pression utilisant le vide absolu comme référence (voir figures 1 et 2)

Absolutdruck (m)

Druck bezogen auf das absolute Vakuum (Siehe Bilder 1 und 2.)

Separator that retains certain ble and insoluble contaminants by molecular adhesion

solu-séparateur (m) par absorption

Séparateur qui retient certains taminants solubles et insolubles par adhérence moléculaire

con-absorbierender Abscheider

(m)

Abscheider, der bestimmte lösliche und nichtlösliche Verschmutzung durch molekulare Adhäsion zurück-hält

Output the power of which in all sible states of the device is derived from supply power

pos-sortie (f) active

Sortie de puissance d’un appareil dont tous les états possibles ne dépendent que de l’énergie d’ali-mentation

aktiver Ausgang (m)

Ausgang, der seine Energie in allen Schaltzuständen des Gerätes nur von der Energieversorgung bezieht

Valve that requires a power supply independent of the value of input signals

distributeur (m) actif

Distributeur qui nécessite une mentation indépendante de la valeur des signaux d’entrée

ali-aktives Ventil (n) (P)

Ventil, das unabhängig von der Größe der Eingangssignale eine Energieversorgung erfordert

temperature

Temperature of a component sured at a specified point at a given time

mea-température (f) réelle d’un

composant

Température d’un composant rée en un point déterminé à un instant donné

mesu-Bauteil-Isttemperatur (f)

Temperatur eines Bauteiles sen an einem bestimmten Punkt zu einer bestimmten Zeit

gemes-ISO 8625-3 -

done

actual fluid temperature

Temperature of the fluid measured

at a specified point in a system at a given time

température réelle (f) d’un

fluide

Température d’un fluide mesurée en

un point déterminé d’un système à

un instant donné

Fluid-Isttemperatur (f)

Temperatur eines Fluids gemessen

an einem bestimmten Punkt in der Anlage zu einem bestimmten Zeit-punkt

Pressure existing at a particular point at a particular time

Final position of the valving element under the influence of the actuating forces

position (f) commandée

Position finale dans laquelle se trouve un élément de manoeuvre de distribution sous l’action des forces

de commande

geschaltete Stellung (f)

Position die das Schaltelement unter Einwirkung der Betätigungskräfte eingenommen hat

Time during which the component is actuated

Druck-N 37- done adaptor

Device that allows connection of parts whose interfaces are incompa-tible

adaptateur (m)

Dispositif permettant de relier des pièces dont les interfaces sont incompatibles

Adapter (m)

Gerät zum Verbinden von Teilen mit unterschiedlichen Anschlüssen/Anschlußbildern

Chemical added to a hydraulic fluid

to impart new properties or to enhance those which already exist

Der Druckflüssigkeit zugesetzte Chemikalie, um ihr neue Eigen-schaften zu verleihen oder um bereits bestehende Eigenschaften

zu verbessern

Flow control valve with a restrictable flow path between the inlet and out-let ports The cross-sectional area of the restrictable flow path can be varied within limits

réducteur (m) de débit

réglable

Régulateur de débit à voie réduite entre les orifices d’entrée et de sor-tie La section de passage restreinte peut varier entre certaines limites

einstellbares Drosselventil (n)

Stromventil, in dem zwischen Ein- und Ausgang eine veränderbare Drosselstelle ist, deren Querschnitt innerhalb von Grenzen verändert werden kann

Cylinder in which the position of a stop can be changed to permit the length of the stroke to be varied

vérin (m) à course réglable

Vérin dans lequel la position d’arrêt peut être modifiée pour permettre un changement de longueur de course

Zylinder (m) mit einstellbarem

adjustable stud end connector

Stud end connector that allows cific orientation before final tighte-ning

spe-connecteur (m) à extrémité

orientable

Connecteur dont l’extrémité permet une orientation spécifique avant le serrage final

richtungseinstellbarer

Einschraubzapfen (m)

Anschlußteil, mit dem die schraubung vor dem endgültigen Festziehen der Gegenmutter ausge-richtet werden kann

com-agglomérat (m)

Combinaison, juxtaposition ou regroupement par n’importe quel moyen de deux ou plusieurs particu-les

Agglomerat (n)

Zwei oder mehr Teilchen, die wie miteinander verbunden sind

Means of purging air from a system

Device that allows the exchange of air between a component (e.g

reservoir) and the atmosphere

reniflard (m)

Dispositif qui permet l’échange d’air entre un composant (par exemple, réservoir) et l’atmosphère

Belüfter (m)

Vorrichtung, die den Austausch von Luft zwischen einem Bauteil (z.B Behälter) und der Atmosphäre erlaubt

5.3.8 and from

96-03 meeting -

done

air breather capacity

Measure of air flow rate through an air breather

capacité (f) en débit d’un

Sub-system that converts cal energy into pneumatic fluid power

mechani-compresseur (m) d’air (P)

Sous-système qui convertit gie mécanique en énergie pneuma-tique

l’éner-Kompressor (m) (P)

Teilanlage, die mechanische gie in pneumatische Energie wan-delt

Ener-8.4 - done air conditioning unit (P)

(pref.); FRL unit (P) (sec.)

Assembly usually comprising a filter,

a pressure regulator and a tor, intended to deliver compressed air in suitable condition

lubrica-ensemble (m) de conditionnement d’air (préf.);

ensemble FRL (P) (sec.)

Ensemble comprenant un filtre, un régulateur de pression et un lubrifi-cateur, destiné à fournir un air com-primé dans des conditions appropriées

Druckluft-Wartungseinheit (f) (P); FRL-Einheit (f) (P)

Baugruppe, die aus einem Filter, einem Druckregelventil und einem Öler besteht und aufbereitete Druck-luft liefert

Air flow required to perform a given task or volume of air used over a stated period of time

consommation (f) d’air (P)

Flux d’air nécessaire pour réaliser une tâche donnée ou volume d’air utilisé sur une période de temps déterminée

Luftverbrauch (m) (P)

Für eine bestimmte Aufgabe tigter Luftvolumenstrom oder benö-tigtes Luftvolumen während einer bestimmten Zeit

Equipment for reducing the moisture vapour content of the compressed air

sécheur (m) d’air (P)

Équipement permettant de réduire le contenu en vapeur humide de l’air comprimé

Lufttrockner (m) (P)

Gerät zur Reduzierung des tigkeitsgehaltes der Druckluft

Port which provides passage to the exhaust system

Component the function of which is the retention of contaminants from atmospheric air

filtre (m) à air (P)

Composant ayant pour fonctions de retenir les polluants et d’enlever l’eau contenue dans l’air comprimé

Luftfilter (m) (P)

Bauteil, dessen Funktionen die Zurückhaltung der Verschmutzungs-stoffe aus der Druckluft und die Abscheidung von Wassertröpfchen ist

from comment

Type of flow control valve that, under normal circumstances, allows free flow in both directions, but that, in the event of a piping failure on either side of the component, will reduce the flow rate to a very low value

NOTE – Full flow conditions will not

be restored until the failure is fied An air fuse may be used as a safety component and/or to reduce air wastage

Volume of air in a system’s fluid

NOTE – Air inclusion is expressed in percentage of volume

Continuous rotation motor that is actuated by compressed air

Compressed air filter used where a very clean air supply is necessary

purificateur (m) d’air (P)

Filtre à air comprimé comportant un élément filtrant à haute efficacité, uti-lisé lorsqu’il est nécessaire d’avoir une alimentation en air très propre

Luft-Feinfilter (m,n) (P)

Druckluftfilter mit einem ment, das einen hohen Abscheide-grad hat

Ability of a hydraulic fluid to release air bubbles dispersed there in

5.2.4.8 - done air-line drain port (P)

Port that enables liquid to be drained from a pneumatic system

orifice (m) de purge d’air (P)

Orifice permettant d’évacuer le liquide drainé dans un système pneumatique

Wasserablaßanschluß (m) (P)

Austrittsöffnung zum Ablassen einer Flüssigkeit aus einer pneumatischen Anlage

See pneumatic-hydraulic converter.

Conditions (e.g pressure, ture, etc.) of the immediate surroun-dings of the system

tempera-conditions (f) ambiantes

Conditions règnantes (par exemple prression, température, etc.) dans l’environnement immédiat d’un système

Umgebungsbedingungen (f)

Bedingungen (z.B Druck, tur) in der unmittelbaren Umgebung der Anlage

Temperature of the environment in which the component, piping or system is working

température (f) ambiante

Température de l’environnement dans lequel est utilisé le composant,

le tuyautage ou le système

Umgebungstemperatur (f)

Temperatur des umgebenden mes, in dem das Bauteil, das Lei-tungssystem oder die Anlage arbeitet

See axial piston motor, bent axis design.

moteur (m) à pistons inclinés

Voir moteur à pistons axiaux, ception à axes inclinés.

con-Siehe Axialkolbenmotor,

Schrägach-senbauweise.

See axial piston pump, bent axis design.

pompe (f) à pistons inclinés

Voir pompe à pistons axiaux, ception à axes inclinés.

con-Siehe Axialkolbenpumpe,

Schräg-achsenbauweise.

N 37 and Mr

Non-return valve used to assist in the prevention of cavitation

Ability of a hydraulic fluid to prevent metal corrosion

NOTE – This is particularly important

in the case of water containing fluids

Korrosionsschutzvermögen

(n) (H)

Fähigkeit einer Druckflüssigkeit, vor metallischer Korrosion zu schützen.ANMERKUNG: Dies ist besonders bei wasserhaltigen Druckflüssigkei-ten von Bedeutung

back-up ring (sec.)

Device in the form of a ring which is designed to prevent extrusion of a seal into a clearance between the two mating parts being sealed

bague (f) anti-extrusion

(préf.); bague (f) d’appui (sec.)

Dispositif ayant la forme d’une bague, conçu pour empêcher l’extrusion d’un joint dans le jeu des deux pièces correspondantes à étancher

Stützring (m)

Ringförmiges Element, das das eindrängen eines Dichtungselemen-tes in den Spalt zwischen zwei abzudichtenden Teilen verhindert

Verschleißschutzvermögen

(n) (H)

Fähigkeit einer Druckflüssigkeit, metallische Berührungen zwischen sich bewegenden Oberflächen unter bekannten Betriebsbedingun-gen durch Erhaltung eines Flüssig-keitsfilms zu verhindern

done assembly

Sub-division of a system or stem, comprising two or more inter-connected components

subsy-assemblage (m)

Subdivision d’un système ou d’un sous-système comprenant au moins deux composants intercon-nectés

Baugruppe (f)

Teil einer Anlage oder einer lage, der zwei oder mehr miteinan-der verbundener Bauteile umfaßt

Teilan-ISO 8434-1,

8434-2, 8434-3

and 8434-4 -

done

assembly torque (pref.);

mounting torque (sec.)

Torque required to achieve a factory final connection

zu erreichen

ISO 8573-1 -

Dewpoint measured at atmospheric pressure

NOTE – The term “atmospheric dewpoint” should not be used in con-nection with compressed-air drying

Absolute pressure of the atmosphere at a given location and time (See figures 1 and 2.)

pression (f) atmosphérique

Pression absolue de l’atmosphère

en un lieu et à un instant donnés

(Voir figures 1 et 2.)

Atmosphärendruck (m)

Absolutdruck der Atmosphäre an einem bestimmten Ort und zu einer bestimmten Zeit (Siehe Bilder 1 und 2.)

Reservoir for storing hydraulic fluid

at atmospheric pressure

réservoir (m) atmosphérique

(H)

Réservoir servant à emmaganiser

du fluide hydraulique à la pression atmosphérique

belüfteter Behälter (m) (H)

Behälter in dem die Flüssigkeit unter atmosphärischem Druck steht

DIN 24550T1 -

Hydraulic filter that is attached to the reservoir and whose housing pene-trates the reservoir wall It uses interchangeable filter elements and filters hydraulic fluid from the return line

filtre (m) de retour non

amovible (H)

Filtre hydraulique fixé à un réservoir

et dont le corps pénètre dans la paroi du réservoir Ce filtre utilise des éléments filtrants interchangea-bles et filtre le fluide hydraulique de

la ligne de retour

Anbau-Rücklauffilter (n, m) (H)

Hydraulikfilter mit auswechselbarem Filterelement, dessen Gehäuse am Behälter angebaut ist und mit der Auslauföffnung in den Behälter hin-einragt

DIN 24550T1 -

Hydraulic filter that is attached to the reservoir and whose housing pene-trates the reservoir wall It uses interchangeable elements and fil-ters hydraulic fluid entering the suc-tion line

filtre (m) d’aspiration non

amovible (H)

Filtre hydraulique fixé à un réservoir

et dont le corps pénètre dans la paroi du réservoir Ce filtre utilise des éléments filtrants interchangea-bles et filtre le fluide hydraulique entrant par la ligne d’aspiration

Anbau-Saugfilter (n, m) (H)

Hydraulikfilter mit auswechselbarem Filterelement, dessen Gehäuse am Behälter angebaut ist und mit der Ansaugöffnung in den Behälter hin-einragt

Temperature at which the fluid hes into flame without an external ignition source

flas-NOTE – Actual value is to be mined by one of several approved test methods

Selbstzündungstemperatur (f)

Temperatur, bei der sich die keit ohne äußere Zündquelle ent-zündet

Flüssig-ANMERKUNG – Der tatsächliche Wert muß nach einem der zugelas-senen Prüfverfahren bestimmt wer-den

Drain valve that automatically discharges any contamination that has been collected, when a prede-

10.4.2.3 - done automatic particle counting

Measurement of solid particle mination in a fluid by automatic means

conta-comptage (m) automatique de

particules

Mesure de la pollution particulaire d’un fluide par des moyens automa-tiques

automatische Partikelzählung

(f)

Automatische Messung der stoffverschmutzung in einem Druck-medium

Valve designed to close cally when the pressure drop across the valve, caused by increased flow, exceeds a predetermined amount

automati-vanne (f) d’isolement

automatique

Vanne conçue pour se fermer matiquement lorsqu’une perte de charge de la vanne, due à une aug-mentation du débit, excède une valeur prédéterminée

auto-Leitungsbruchventil (n)

Ventil, das selbsttätig sperrt, wenn durch einen zu hohen Volumen-strom eine vorgegebene Druckdiffe-renz überschritten wird

Receiver that is installed in the system to supply local demands

réservoir (m) auxiliaire d’air

(P)

Réservoir installé dans un système pour régulariser les demandeslocales d’alimentation

Druck-Ausgleichsbehälter

(m) (P)

Behälter in einer Pneumatikanlage zur Kompensation von örtlichen Ver-brauchsschwankungen

3.2.2.1.8.2 -

Hydraulic motor having several pistons which are parallel to one another

moteur (m) à pistons axiaux

(H)

Moteur hydraulique possédant sieurs pistons parallèles les uns aux autres

plu-Axialkolbenmotor (m) (H)

Hydromotor mit mehreren Kolben, die parallel zueinander angeordnet sind

from 96-03

design (pref.);

angled piston motor (sec.)

Axial piston motor in which the drive shaft is at an angle to the common axis

moteur (m) à pistons axiaux,

conception à axes inclinés

(préf.); moteur (m) à pistons

inclinés (sec.)

Moteur à pistons axiaux dans lequel l’arbre d’entraînement est incliné par rapport à l’axe commun

Axialkolbenmotor (m),

Schrägachsenbauweise

Axialkolbenmotor, bei dem die Abtriebsachse und die Kolbenach-sen winklig zueinander stehen

moteur (m) à pistons axiaux,

conception à plateau oscillant

Moteur à pistons axiaux dans lequel l’arbre d’entraînement est aligné avec l’axe commun Le plateau osci-llant n’est pas relié à l’arbre d’entraî-nement

Axialkolbenmotor (m),

Schrägscheibenbauweise

Axialkolbenmotor, bei dem die Abtriebsachse und die Kolbenach-sen zueinander parallel sind.Die nicht mit der Abtriebsachse ver-bundene Schrägscheibe steht dabei fest

Hydraulic pump having several pistons which are parallel to one another

pompe (f) à pistons axiaux (H)

Pompe hydraulique possédant sieurs pistons parallèles les uns aux autres

plu-Axialkolbenpumpe (f) (H)

Hydropumpe mit mehreren Kolben, die parallel zueinander angeordnet sind

design (pref.);

angled piston pump (sec.)

Axial piston pump in which the drive shaft is at an angle to the common axis

pompe (f) à pistons axiaux,

conception à axes inclinés

(préf.); pompe (f) à pistons

inclinés (sec.)

Pompe à pistons axiaux dont l’arbre d’entraînement forme un angle avec l’axe commun

Axialkolbenpumpe (f),

Schräg-achsenbauweise

Axialkolbenpumpe, bei der die Antriebsachse und die Kolbenach-sen winklig zueinander stehen

design

Axial piston pump in which the drive shaft is in line with the common shaft The swash plate is not connected to the drive shaft

pompe (f) à pistons axiaux,

conception à plateau oscillant

Pompe à pistons axiaux dont l’arbre d’entraînement est aligné avec l’axe commun Le plateau oscillant n’est pas relié avec l’arbre

done axial piston pump, wobble

design

Axial piston pump in which the drive shaft is in line with the common shaft Pistons are actuated by a swashplate which is connected to the drive shaft

pompe (f) à pistons axiaux,

conception à plateau oscillante

Pompe à pistons axiaux dont l’arbre d’entraînement est aligné avec l’axe commun Les pistons sont actionnés par un plateau oscillant, qui est relié

Sealing device that seals by axial contact force

Pressure which acts against force or pressure

See anti-extrusion ring.

Connector, attached using a hollow bolt that provides for fluid flow, which permits fluid flow at a plane 90° to the connecting port, and in any direction (360o) therefrom

connecteur (m) banjo

Connecteur auquel est adjoint un boulon creux permettant le passage d’un fluid fluide dans un plan 90° de l’orifice de connexion et à partir de là dans toutes les directions (360°)

Ringstutzen (m)

Verbinder, der unter Verwendung einer Hohlschraube – ausgelegt für Durchfluß – befestigt ist, und der Durchfluß, im 90°-Winkel zum Anschluß, in jede Richtung erlaubt.3.2.2.1.7.2 -

Vane motor in which the transverse forces on the rotor are balanced

moteur (m) à palettes

équilibré

Moteur à pallettes dans lequel les forces radiales qui agissent sur le rotor sont équilibrées

ausgeglichener

Flügelzellenmotor (m)

Flügelzellenmotor, in dem die len Kräfte auf den Rotor ausgegli-chen sind

radia-ball valve

Valve in which ports are connected

or sealed off by a rotating shaped valving element containing flow paths

ball-soupape (f) à bille

Soupape dont les orifices sont cordés ou étanchés par un élément

rac-de manoeuvre rac-de distribution rotatif

en forme de bille contenant les sages assurant l’écoulement

pas-Kugelhahn (m)

Ventil, bei dem die gen durch ein drehbares kugelförmi-ges Element, das die Strompfade (Durchflußwege) enthält, freigege-ben oder gesperrt werden

Anschlußöffnun-N 24 and Anschlußöffnun-N 59 -

done

bellows actuator

Type of single acting linear actuator

in which mechanical force and motion are produced by the expan-sion of a flexible bellows, consisting

of one or more convolutes, without the use of a piston and piston rod

actionneur (m) à soufflets

Type d’actionneur linéaire simple dans lequel la force mécanique et le mouvement sont produits par l’extension de soufflets flexibles, comprenant une ou plusieurs circon-volutions, sans utilisation d’un piston

et d’une tige de piston

Balgzylinder (m)

Einfachwirkender Linearantrieb, in dem mechanische Kraft und Bewe-gung durch Ausdehnung eines flexi-blen, ein- oder mehrfaltigen Balgs, ohne Kolben und ohne Kolben-stange, aufgebracht wird

Filter element designed to filter fluid

Zwei-Richtungs-Filterelement

(n)

Filterelement zum Filtern von den in zwei Richtungen

Flui-4.3.1.9 - done bi-directional pressure relief

valve

Pressure relief valve having two ports, either of which can be used as the inlet when the other will become the outlet without making any physi-cal change or adjustment to the valve

soupape (f) de décharge de

pression bidirectionnelle

Soupape de décharge de pression à deux orifices pouvant être indif-féremment utilisés comme entrée ou comme sortie, sans avoir à effectuer une modification physique ou un réglage de la soupape

Zwei-Richtungs-Druckbegrenzungsventil (n)

Druckbegrenzungsventil mit zwei Anschlüssen, von denen jeder als Eingang verwendet werden kann Der andere Anschluß ist dann jeweils Ausgang, ohne Veränderun-gen am Ventil vornehmen zu müs-sen

Gas-loaded accumulator in which separation is achieved by a flexible bladder

accumulateur (m) à vessie (H)

Accumulateur à gaz dans lequel le liquide et le gaz sont séparés par une vessie flexible (sac fexible) nor-malement retenue à une extrémité

du corps de l’accumulateur

Blasenspeicher (m) (H)

Gasdruckspeicher, in dem die sigkeit vom Gas durch eine flexible Blase getrennt wird und im Normal-fall an einem Behälterende zurück-gehalten wird

Line through which air is purged from a hydraulic system

Form of pilot-operated non-return valve screwed directly into a cylinder inlet port, so that air will be trapped

in the cylinder when the pilot signal

is removed

Simple manually-operated two-port valve used to discharge compressed air to atmosphere

Seal using elastomeric material bonded to a rigid substrate

Static gasket seal consisting of a flat metal washer bonded to a concentric elastomeric sealing ring

rondelle (f) composite

Garniture d’étanchéité statique prenant une rondelle métallique plate accolée à un anneau concen-trique en élastomère

com-Verbunddichtungsscheibe (f)

Statische Flachdichtung, bestehend aus einer metallischen Dichtungs-scheibe, die mit einem konzentri-schen elastomeren Dichtungsring verbunden ist

Pressure at which replenishing liquid

is supplied (usually to closed loop circuits or second stage pumps)

pression (f) de gavage

Pression à laquelle le liquide de remplissage est introduit (habituelle-ment dans des circuits fermés ou dans le second étage des pompes)

Speisedruck (m)

Druck, unter dem eine Flüssigkeit ergänzt wird (üblicherweise für geschlossene Getriebekreise oder Zweistufenpumpen)

breakout pressure (sec.)

Minimum pressure necessary to initiate movement

pression (f) d’amorçage

Pression minimale nécessaire pour initier le mouvement

Losbrechdruck (m) (pref.); Anfahrdruck (m) (sec).

Erforderlicher Mindestdruck, um eine Bewegung einzuleiten

See breakaway pressure.

pression (f) de

déchenchement

Voir pression d’amorçage

Siehe Losbrechdruck.

done bulk modulus of a fluid

Relationship between a change in pressure applied to a fluid and the resultant volumetric strain

coefficient (m) de charge d’un

fluide

Relation entre la charge appliquée sur toutes les parties du fluides et la déformation volumétrique Cela mesure la résistance à la compressi-bilité d’un fluide et c’est l’inverse de

Connector for tubes and hoses on either side of a bulkhead or wall which allows fluid passage through the bulkhead or wall

connecteur (m) passe-cloison

Connecteur disposé de chaque cơté d’une cloison ou d’un mur pour rac-corder des tubes ou des flexibles et permettant le passage du fluide à travers cette cloison ou ce mur

Schottstutzen (m)

Stutzen für Rohre und Schläuche auf jeder Seite eines Schotts oder einer Trennwand, der Fluidstrom durch das Schott oder die Trenn-wand hindurch erlaubt

Outward structural failure caused by excessive pressure (for example, fil-ter burst, hose burst)

rupture (f)

Défaillance structurelle laissant échapper vers l’extérieur, le contenu d’une enveloppe solide, due à une pression excessive (par exemple, rupture de filtre, rupture de flexible)

Bersten (n)

Nach außen gerichtetes Versagen des Materialgefüges durch zu hohen Druck (z.B Filterbersten, Schlauch-bersten)

Test pressure at which a component

or piping fails and fluid begins to escape (See figure 2.)

pression (f) de rupture

Pression d’essai à laquelle un posant ou le tuyautage devient défaillant et ó le fluide commence à s’échapper (voir figure 2)

com-Berstdruck (m)

Prüfdruck, bei dem ein Bauteil oder Leitungssystem birst und Fluid aus-tritt (Siehe Bild 2)

Straight-through valve in which the valve element consists of a flat disc rotating about a diametrical axis per-pendicular to the flow of fluid

vanne (f) papillon

Vanne à passage direct dans laquelle l’élément de distribution est constitué par un disque plat tournant autour d’un axe perpendiculaire à l’écoulement du fluide

Klappe (f)

Absperrarmatur, bei der das Schließelement eine Scheibe ist, die sich um eine senkrecht zur Strư-mungsrichtung stehende Achse dre-hen läßt

See three-port flow control valve.

régulateur (m) de débit à

dérivation

Voir régulateur de débit à trois voies.

Siehe Drei-Wege-Stromregelventil.

Valve that can operate only in junction with an associated housing containing the necessary flowpaths

con-distributeur (m) à cartouche

Distributeur qui peut fonctionner qu’inclus dans un fourreau ayant les conduits d’écoulement nécessaires

Patronenventil (n)

Ventil , das nur in Verbindung mit einem zugehưrigen Gehäuse, das die notwendigen Durchflußpfade enthält, funktioniert

Formation of cavities, either ous or vapour, within a liquid stream, which occurs where the pressure is locally reduced to the critical pres-sure, normally the vapour pressure

gase-of the liquid

NOTE – During the state of tion, the liquid can move across the cavities at high velocity, producing a hammer effect, which may not only cause noise but eventual damage to components

cavita-cavitation (f) (H)

Phénomène du à la formation de cavités sous forme de bulles de gaz

ou de vapeur au sein d’un liquide en mouvement, et qui se produit lors-que la pression dans le liquide devient localement inférieure à la tension de vapeur de celui-ci

NOTE – Lorqu’il y a cavitation, le liquide peut se mouvoir à une grande vitesse, à travers les cavités produisant un effet de coup de mar-teau, qui peut non seulement créer des vibrations de type bruit mais aussi éventuellement endommager les composants

Kavitation (f) (H)

Bildung von Hohlräumen, gas- oder dampffưrmig, in einem Flüssigkeits-strom, die dann eintritt wenn der Druck ưrtlich bis zum Dampfdruck der Flüssigkeit absinkt

ANMERKUNG: Im Zustand der Kavitation kann sich die Flüssigkeit mit hoher Geschwindigkeit in diese Hohlräumen bewegen, einen Ham-mereffekt erzeugend, der nicht nur Geräusch verursacht, sondern evtl auch Bauteile zerstưrt

N 37 - done centre open to exhaust

position (P) (pref.); negative position (sec.); supply sealed mid-position (sec.)

Valve centre position in which the inlet supply is not connected to an outlet, but outlets are connected to exhaust

symbol

position (f) centre ouvert à l’échappement (P) (préf.);

position (f) négative (sec.);

position (f) milieu avec alimentation étanche (sec.)

Position centrale d’un distributeur dans laquelle l’alimentation à l’ent-rée n’est pas reliée à une sortie, mais ó les sorties communiquent avec l’échappement

symbole

Mittelstellung (f), entlüftet (P)

Mittlere Stellung des Ventils, in der der Versorgungsanschluß gesperrt ist und die Arbeitsanschlüsse mit den Entlüftungsanschlüssen verbun-den sind

position (P) (pref.); positive position (sec.)

Valve centre position in which the inlet supply is connected to both out-lets and exhaust ports are closed

symbol

position (f) centre ouvert sous pression (préf.); position (f) positive (sec.) (P)

Position centrale d’un distributeur dans lequel l’alimentation à l’entrée est en communication avec les sor-ties, les échappements étant fer-més

symbole

Mittelstellung (f), belüftet (P)

Mittlere Stellung des Ventills, in der der Versorgungsanschluß mit bei-den Arbeitsanschlüssen verbunden ist und die Entlüftungsanschlüsse gesperrt sind

Filter in which contaminants are retained from the fluid by circulating fluid in a rotary manner

filtre (m) centrifuge

Filtre dans lequel la séparation des polluants est obtenue en animant le fluide d’un mouvement circulaire

Zentrifuge (f)

Filter, bei dem die Schmutzstoffe durch kreisfưrmige Bewegung des Fluids zurückgehalten werden

Pump in which the increase of fluid energy is derived from kinetic energy (the quantity of fluid delivered is rela-ted to the output pressure)

pompe (f) centrifuge

Pompe dans laquelle ment d’énergie fluide provient de l’énergie cinétique (la quantité de fluide fournie est fonction de la pres-sion de sortie)

l’accroisse-Kreiselpumpe (f)

Eine Pumpe, bei der der wachs eines Fluids im wesentlichen von der kinetischen Energie bestimmt wird (der Fưrderstrom ist abhängig vom Ausgangsdruck)

Separator that uses radial tion to isolate liquid and/or solid par-ticles of specific gravity different from that of the fluid being cleaned

Fliehkraftabscheider (m)

Abscheider, der mittels radialer Beschleunigung flüssige und/oder feste Teichen, deren spezifisches Gewicht unterschiedlich zu dem des

zu reinigenden Fluids ist, aus sem entfernt

Pressure to which a component is charged or inflated

See non-return valve.

clapet (m) anti-retour

Occurrence when upstream

pres-sure, p1, is high in relation to the

downstream pressure, p2, such that the velocity in some part of the com-ponent becomes sonic The mass flow of the gas is proportional to the

upstream pressure, p1, and dent of the downstream pressure,

indepen-p2

écoulement (m) sonique (P)

Situation qui se produit lorsque la pression amont, p1, est suffisament élevée par rapport à la pression aval, p2, de manière à ce que la vitesse du fluide devienne sonique

en un point du composant Le masse du gaz est proportionnel à la pression amont, p1, et indépendant

débit-de la pression aval, p2

überkritische Strưmung (f) (P)

Erscheinung, die auftritt, wenn der

Eingangsdruck p1 im Verhältnis zum

Ausgangsdruck p2 so groß ist, daß die Durchflußmenge proportional

dem Eingangsdruck p1 und

unab-hängig vom Ausgangsdruck p2 ist Dieser Zustand ist erreicht, wenn die Luftgeschwindigkeit an irgendeiner Stelle des durchstrưmten Bauteiles der Schallgeschwindigkeit ent-spricht

5.8.2.1- done cleanable filter element

Filter element that when clogged can

be restored by a suitable process to

an acceptable percentage of its ginal flow/pressure differential cha-racteristic

ori-élément (m) filtrant nettoyable

Elément filtrant qui, lorsqu’il est maté, peut être régénéré par un procédé convenable, en obtenant un pourcentage acceptable de la carac-téristique de débit/pression différen-tielle existant à l’état origine

col-reinigbares Filterelement (n)

Filterelement, das, wenn es schmutzt ist, durch ein geeignetes Verfahren soweit gereinigt werden kann, daß ein akzeptabler Prozent-satz der ursprünglichen Volumen-strom-/Druckdifferenz-Charakteri-stik wieder erreicht wird

Opposite of contamination level

Verstopfung (f)

Volumenstromreduzierung durch Ablagerung von festen oder flüssi-gen Teilchen

Valve centre position which causes all valve ports to be closed

symbol

position (f) centre fermée

Position centrale d’un distributeur qui correspond à la fermeture de tous les orifices

Mittelstellung(f), geschlossen

Mittlere Stellung eines Ventiles, bei der alle Ventilanschlüsse geschlos-sen sind

8.5.11 and

Circuit in which return fluid is ted to the pump inlet

direc-circuit (m) fermé (H)

Circuit dans lequel le fluide fait tement retour à l’entrée de la pompe

direc-geschlossener Kreislauf (m)

(H)

Schaltung, bei der der strom direkt zum Pumpeneingang geleitet wird

Position of the valving element which causes all valve ports to be closed

position (f) fermée (H)

Position de l’élément de manoeuvre

de distribution qui provoque la meture de tous les orifices

fer-geschlossene Stellung (f)

(Sperrstellung) (H)

Stellung des Schaltelementes, bei der alle Ventilanschlüsse geschlos-sen sind

Position of the valving element in which inlet supply is not connected

to an outlet

position (f) fermée (P)

Position de l’élément de manoeuvre

de distribution pour laquelle l’entrée d’alimentation n’est pas relié à une sortie

geschlossene Stellung (f) (P)

Stellung des Schaltelementes, bei der der Versorgungsanschluß mit keinem Ausgang verbunden ist

pression (f) de fermeture

Pression utilisée pour assurer la meture d’un composant dans des conditions définies, par exemple, de débit

fer-Schließdruck (m)

Druck zum Schließen eines les unter definierten Bedingungen, z.B des Volumenstromes

Filter in which retention of nants occurs due to the difference in wetting properties on a particular porous medium, leading to liquid particles in suspension combining into particles of greater volume

contami-filtre (m) coalescent

Filtre dans lequel la rétention des polluants est due à la différence des propriétés de mouillage des consti-tuants d’un liquide sur un matériau poreux particulier, entraînant l’agglo-mération en volume des particules

en suspension dans le liquide

Coalescer-Filter (n, m)

Filter, bei dem die Abscheidung von Verunreinigungen infolge der unter-schiedlichen Feuchtigkeitsaufnah-mebereitschaft eines bestimmten porösen Filtermediums geschieht Dies führt dazu, daß die frei schwe-benden Flüssigkeitsteilchen sich zu Teilchen größeren Volumens verei-nigen

effect (P) (pref.); expansion factor (sec.)

Coefficient which takes into account the effects of the gas compressibility when flow is subsonic

coefficient (m) d’effet de

compressibilité (P)

Coefficient qui tient compte des effets de la compressibilité du gaz lorsque l’écoulement est subso-nique

Kompressibilitätsbeiwert (m)

(P)

Beiwert zur Berücksichtigung der Auswirkungen der Gaskompressibili-tät, bei unterkritischer Durchflußge-schwindigkeit

5.8.3.2 - done collapse

Inward structural failure caused by excessive pressure differential (for example, filter element collapse)

déformation (f)

Défaillance structurelle interne due à une pression différentielle exces-sive (par exemple, déformation d’un élément filtrant)

Kollabieren (n)

Nach innen gerichtetes Versagen des Materialgefüges durch zu hohes Druckgefälle (z.B Filterelementkol-labieren)

Hardened, longitudinally split ring that closes on a tube’s outside dia-meter surface, exercising grip, but not sealing

Klemmring (m)

Gehärteter, längsgeteilter Ring, der ein Rohr am Außendurchmesser fest umschließt, aber nicht abdichtet

Fluid that does not adversely ence the nature and life of a system, components, piping or another fluid

influ-fluide (m) compatible

Fluide qui n’exerce pas une ence défavorable sur la nature et la vie d’un système, de composants,

influ-du tuyautage ou sur un autre fluide

verträgliches Druckmedium

(n)

Druckmedium, das die Funktion und Lebensdauer von Bauteilen oder Leitungssystemen nicht merklich beeinflußt

composant (m)

Unité individuelle (par exemple, vérin, moteur, distributeur, filtre, mais excluant le tuyautage) com-prenant une ou plusieurs pièces conçues comme organe fonctionnel d’un système de transmissions hydrauliques et pneumatiques

Bauteil (n)

Eine einzelne Einheit (z.B Zylinder, Motor, Ventil, Filter, ausschließlich Leitungssystemen), bestehend aus einem oder mehreren Teilen, als funktionaler Bestandteil von fluid-technischen Anlagen entworfen

Filter element composed of two or more types, grades or arrangements

of filter media to provide properties that are not available in a single filter medium

élément (m) filtrant composite

Élément filtrant composé de deux ou plusieurs types, classes ou dispositi-ons de matériaux filtrant ayant des propriétés que ne possèdent pas les filtres à un seul média filtrant

Verbundfilterelement (n)

Aus zwei oder mehr Arten, heitsgraden oder Anordnungen von Fillterwerkstoffen aufgebautes Filter-element, um Eigenschaften zu erhal-ten, die mit einem einfachen Filterwerkstoff nicht erreichbar sind

Sealing device having two or more elements of different materials

NOTE – Examples of composite seals are bonded seals and rotary shaft lip seals

joint (m) composite

Dispositif d’étanchéité comprenant deux ou plusieurs éléments de matières différentes

NOTE – Les joints en aggloméré et les joints à levres pour arbre rotatif sont des exemples de joints compo-sites

zusammengesetzte Dichtung

(f)

Dichtung, die aus zwei oder mehr Elementen verschiedener Werk-stoffe besteht

ANMERKUNG: Beispiele mengesetzter Dichtungen sind Ver-bunddichtungen und Radial-Wellendichtringe

Atmospheric air compressed to a higher pressure, used as a power transmitting medium

ISO 5782-1 and

(pref.); pneumatic filter (P) (sec.)

Component designed to retain solid and liquid contaminants present in compressed air

filtre (m) à air comprimé (P)

Composant conçu pour retenir les polluants solides et liquides con-tenus dans l’air comprimé

Druckluftfilter (m, n) (P)

Bauteil zum Zurückhalten von festen und flüssigen Schmutzstoffen aus Druckluft

NOTE – The filter is always on the upstream side of the regulator.

filtre-régulateur (m) pour air

(pref.); pneumatic lubrication

(P) (sec.)

Introduction of lubricant into the air supply to a pneumatic system or component in the form of a fine oil mist

lubrification (f) d’air comprimé

(P)

Introduction de lubrifiant sur mentation en air d’un système pneu-matique ou d’un composant, sous forme d’un fin brouillard d’huile

l’ali-Schmierstoffeintrag (m) in

Druckluft (P)

Einbringen von Schmierstoff in die Luftversorgung einer pneumatischen Anlage oder eines Bauteils in Form von feinem Ölnebel

ISO/CD 6301-1,

-2 and N 30 -

done

compressed air lubricator (P)

(pref.); pneumatic lubricator

Change in volume of a unit volume

of fluid when subjected to a unit change in pressure

compressibilité (f) d’un fluide

Variation en volume de l’unité de volume d’un fluide, soumis à une variation de pression

Kompressibilität (f) eines

Fluids

Volumenänderung einer einheit Fluid durch Änderung des Druckes um eine Einheit

Volumen-ISO 8573-1 -

Drying of air by compressing it to a higher pressure, cooling it and extracting the water condensed, and finally expanding it to the required pressure

séchage (m) d’air par

Lufttrocknung (f) durch

Verdichten (P)

Trocknen von Luft durch Verdichten auf einen höheren Druck, Abkühlen der Luft mit Entziehen des Kondens-wassers und Entspannen der Luft auf den geforderten Druck

(pref.); compression fitting (deprecated)

Connector which uses a nut pressing a ferrule to provide sealing

com-connecteur (m) à compression (préf.); raccord

(m) à compression (déconseillé)

Connecteur qui utilise un écrou primant une virole pour assurer une étanchéité

com-Schneidringverschraubung (f)

Verschraubung, die durch Anziehen eines Schneidringes mittels einer Überwurfmutter dichtet

Leitungsteil (n)

Rohr oder Schlauch, das oder der Fluid zwischen Anschlußstücken lei-tet

(deprecated)

Device that connects pipes, hoses or tubes to each other or to compon-ents, without leakage

connecteur (m) (préf.);

raccord (m) (sec.)

Dispositif qui permet la connexion de tuyaux, flexibles ou de tubes les uns aux autres ou à des composants, de manière à éviter les fuites

Anschlußstück (n);

Verschraubung (f)

Teil, das Rohre oder Schläuche einander oder mit Bauteilen ohne Leckage verbindet

ISO 8573-1 -

Any material or combination of rials (solid, liquid or gaseous) which may adversely affect the system

mate-polluant (m)

Toute matière ou combinaison de matières (solide, liquide ou gazeuse) qui peut avoir une influence néfaste sur un système

Schmutzstoff (m)

Jedes Material oder jede kombination (fest, flüssig oder gas-fưrmig), das/die die Anlage oder den Bediener ungünstig beeinflußt.ISO/WD 11487 -

Reduction of performance caused

Set of numbers used as a shorthand method for describing the particle size distribution of contaminants in hydraulic fluid

NOTE – ISO 4406 defines such a code

parti-NOTE – L’ISO 4406 définit un tel code

Verschmutzungsklassifizie-rung (f) (H)

Zahlensystem zur einfachen mung der Partikelgrưßenverteilung von Schmutzstoffen in einer Druck-flüssigkeit

Bestim-ANMERKUNG: In ISO 4406 ist eine derartige Klassifizierung definiert

Quantitative term specifying the degree of contamination

Bestim-131/5 N 310 -

Valve that controls the flow of energy of a system in a continuous way in response to a continuous input signal

NOTE – This encompasses all types

of servo-valves and proportional control valves

distributeur (m) de commande

à fonctionnement continu

Distributeur qui commande le flux d’énergie d’un système de manière continue en réponse à un signal d’entrée continu

NOTE – Cela enveloppe tous les types de servo-distributeurs et les distributeurs de commande proporti-onnels

Stetigventil (n)

Ventil, das den Energiefluß einer Anlage proportional zu einem steti-gen Eingangssignal steuert.ANMERKUNG: Das umfaßt alle Arten von Proportional- und Servo-ventilen

Intensifier in which continuous cation of primary fluid to the inlet port can produce a continuous flow of secondary fluid

appli-multiplicateur (m) à action

continue

Multiplicateur dans lequel tion continue du fluide primaire à l’orifice d’entrée permet un écoule-ment continu du fluide secondaire

l’applica-kontinuierlich wirkender

Übersetzer (m)

Übersetzer, bei dem das am gang dauernd anstehende Primär-fluid einen kontinuierlichen Strom des Sekundärfluids erzeugt

Flow rate that performs a control function

valve operator (deprecated)

Device that provides an input signal

to a component (e.g lever, noid)

sole-mécanisme (m) de commande

Dispositif qui fournit un signal rée à un composant (par exemple, levier, solénọde)

d’ent-Betätigungseinrichtung (f)

Einrichtung, die ein Bauteil mit einem Eingangssignal versorgt (z.B Hebel, Magnet)

Pressure at a control port used to perform a control function

pression (f) de commande

Pression à un orifice de commande utilisée pour réaliser une fonction de commande

Steuerdruck (m)

Druck an einem Steueranschluß, um eine Steuerfunktion auszuführen

Electrical signal or fluid pressure applied to a control mechanism

signal (m) de commande

9.1.4 - done control system

Means whereby the fluid power system is controlled, linking that system to the operator and to control signal sources, if any

système (m) de commande

Moyens par lesquels un système de transmissions hydrauliques ou pneu-matiques est commandée, assurant

la liaison entre le système et teur, et lorsqu’elles existent avec les sources de signal de commande

l’opéra-Steuerung (f) und Regelung (f)

Vorgänge, bei denen die Anlage durch die Verbindung mit dem Bediener und den Signalgebern, sofern vorhanden, gesteuert oder geregelt wird

Volume of fluid required to perform a control function, including that of the pilot line

volume (m) de commande

Volume de fluide nécessaire à la réalisation d’une fonction de com-mande, incluant celui de la canalisa-tion de commande

Steuervolumen (n)

Erforderliches Volumen des mediums, einschließlich der Steuer-leitung, um eine Steuerfunktion auszuführen

Valve which maintains pressure to prevent a load from falling or over-running

Ventil, das einen Druck aufrecht erhält, um das Fallen einer Last zu verhindern

(pref.); swaged hose

connector (pref.);

crimped hose fitting (sec.);

swaged hose fitting (sec.)

Hose connector attached to the hose

by permanent deformation of one end of the connector

raccord (m) de flexible serti;

raccord (m) de flexible

estampé

Connecteur de flexible rendu daire du flexible par déformation per-manente d’une extrémité du connecteur

soli-Preßarmatur (f)

Schlaucharmatur, die durch bende Verformung eines Armaturen-teils mit dem Schlauch verbunden wird

Ratio of the absolute downstream pressure to the absolute upstream pressure from a restriction in a pneu-matic component, at which the flow becomes sonic

rapport (m) de pressions

critiques (P)

Valeur du rapport de la pression absolue amont et aval dans un com-posant pneumatique, auquel l’écou-lement devient sonique

kritisches Druckverhältnis (n)

(P)

Verhältnis zwischen Absolutdruck stromaufwärts und Absolutdruck stromabwärts in einem Pneumatik-bauteil, bei dem der Volumenstrom Schallgeschwindigkeit erreicht

Numerical reference that indicates whether the flow will be laminar or turbulent for a given set of conditi-ons

nombre (m) de Reynolds

critique

Référence numérique indiquant si

un écoulement est soit laminaire soit turbulent pour un jeu de conditions données

kritische Reynoldszahl (f)

Numerische Bezugsgröße, die anzeigt, ob die Strömung, unter defi-nierten Bedingungen, laminar oder turbulent ist

Connector in the form of a cross

NOTE – It is used to dissipate high pressure surges associated with some hydraulic motor or cylinder applications.

clapet (m) de décharge de

pression double (H)

Distributeur constitué de deux pets de décharge de pression installés dans un corps commun, de manière que l’écoulement puisse se faire dans deux directions

cla-NOTE – Utilisé pour dissiper des sauts de haute pression dans des moteurs hydrauliques ou des appli-cations des vérins

Druckbegrenzungsventil (n)

für gegenseitige Abspritzung (H)

Bauart eines zungsventils, um Volumenstrom in zwei Richtungen zu gestatten.ANMERKUNG: Es wird eingesetzt,

Doppel-Druckbegren-um hohe Druckstöße, die bei chen Hydromotor- oder Hydrozylin-deranwendungen auftreten können,

man-zu vermeiden

Cylinder with a cushioning device

amortissement (m)

Moyens fixes ou réglables grâce auxquels un élément mobile est décéléré lorsqu’il approche de la fin

damping pressure (sec.)

Pressure generated to decelerate the total moving mass

single preferred term)

Ring designed, on tightening a nector’s nut, to seal a connection and secure the connector onto the tube, by penetrating or deforming a tube’s outside diameter surface

con-virole (f); bague (f) coupante;

olive (f) (pas de terme

préférentiel)

Bague conçue sur la base d’un rage d’écrou, pour assurer l’étan-chéité d’une connexion et sa fixation sur un tube, par pénétration ou déformation de la surface du diamètre extérieur du tube

ser-Schneidring (m)

Ring, mit dem durch Anziehen einer Überwurfmutter, eine Verbindung abgedichtet und das Anschlußstück

am Rohr gesichert wird Dies geschieht durch Eindringen des Rin-ges in die Rohroberfläche oder Ver-formung der Rohroberfläche

cycle

One complete set of events or tions, which repeats in an identical, i.e cyclic manner

condi-cycle (m)

Jeu complet d’évènements qui se répètent à l’identique, c’est-à-dire de manière cyclique

Zyklus (m)

Ein vollständige Folge von sen oder Bedingungen, die sich peri-odisch wiederholen

Ereignis-2.1.9 and ISO

Conditions in which the values of the relevant factors vary in a cyclical manner

conditions (f) cycliques

stabilisées

Conditions dans lesquelles les valeurs des facteurs significatifs varient de façon cyclique

zyklisch stabilisierte

Bedingungen (f)

Einsatzbedingungen, unter denen die entsprechenden Kenngrößen periodisch variieren

Value of the difference between the upper cyclic test pressure and lower cyclic test pressure during a fatigue test

NOTE – See also lower cyclic test

pressure and upper cyclic test sure.

pres-pression (f) d’essai cyclique

Valeur de la différence entre la sion supérieure cyclique d’essai et la pression inférieure cyclique d’essai dans un essai de fatigue

pres-NOTE – Voir également pression

inférieure cyclique d’essai et sion supérieure cyclique d’essai.

pres-Druckschwankungsbreite (f)

Wert der Differenz zwischen dem oberen und dem unteren Schwell-druck währed einer Ermüdungsprü-fung

ANMERKUNG: Siehe auch Unterer

Schwelldruck und Oberer druck.

Method for securing a cylinder using

a bracket(s) of angular construction

fixation (f) orientable d’un

vérin

Dispositif destiné à maintenir en position un vérin, en utilisant des crochets ou un ensemble incliné

Zylinderwinkelbefestigung (f)

Zylinderbefestigung mit einem oder mehreren Winkelstücken

N 38 - done cylinder body

Hollow pressure-containing element

in which the cylinder piston travels

corps (m) de vérin

Élément creux contenant la sion, dans laquelle se meut le piston d’un vérin

pres-Zylinderrohr (n); gehäuse (n)

Zylinder-Hohles druckfestes Teil, in dem sich der Kolben bewegt

Internal diameter of the cylinder body

cylinder rear end (sec.);

cylinder non-rod end (sec.)

That end of the cylinder where there

is no piston rod

Symbol with indication of cap and rod end

fond (m) de vérin (préf.);

arrière (m) d’un vérin (sec.);

extrémité (f) d’un vérin ne comprenant pas la tige (sec.)

Extrémité du vérin ne comprenant pas la tigue du piston

Dessin

Zylinderbodenseite (f)

Das Ende des Zylinders, an dem keine Kolbenstange austritt.Skizze

Mounting by means of a U-shaped mounting device through which a pin

or bolt passes, to make a cylinder pivot mounting

Dessin

Zylinder-Gabelbefestigung (f)

U-förmiges Befestigungsteil, das eine Lasche aufnehmen kann und durch den ein Stift oder Bolzen gesteckt wird, um eine Dreh-/Schwenkverbindung herzustellen

Skizze

Control mechanism that uses a cylinder

commande (f) par vérin

Mécanisme de commande réalisé à l’aide d’un vérin

Zylinderbetätigung (f)

Betätigungseinrichtung, bei der ein Zylinder das betätigende Element ist

Distance between the point at which cushioning begins and the end of the stroke

See cylinder outstroke.

course (f) d’extension d’un

vérin

Voir course de sortie du piston

Siehe Zylinder-Vorhub.

See cylinder outstroke force

cylinder pin mounting (sec.)

Mounting by means of a projection

to the cylinder construction through which a pin or bolt passes to make a cylinder pivot mounting

Drawing

fixation (f) par oreilles d’un vérin (préf.); fixation (f) par axe d’un vérin (sec.)

Fixation consistant en un ment à l’arrière du vérin pour per-mettre, grâce à un axe traversant, une liaison à angles droits avec l’axe

Zylinderkon-Skizze

Force generated by pressure acting

on a cylinder piston area

force (f) d’un vérin

Force générée par l’action de la pression sur la surface du piston d’un vérin

Zylinderkraft (f)

Kraft, die durch den auf die fläche des Zylinders wirkenden Druck erzeugt wird

done cylinder front end

See cylinder rod end.

face (f) avant d’un vérin

See cylinder rod end.

tête (f) d’un vérin

cylinder retract stroke (sec.)

Movement whereby a piston rod retracts into the cylinder body In the case of a through-rod or rodless cylinder, the movement whereby the cylinder returns to its initial postion

course (f) de rentrée du piston d’un vérin (préf.); rétraction (f)

du piston d’un vérin (sec.)

Mouvement par lequel une tige de piston rentre dans le corps du vérin

Dans le cas d’une tige traversante

ou d’un vérin sans tige, c’est le vement par lequel le vérin retourne à

mou-sa position initiale

Zylinder-Rückhub (m) (pref.); Zylinder-Eifahrhub (m) (sec.)

Bewegung, bei der eine stange in das Zylinderrohr/-gehäuse zurückfährt Bewegung, bei der, bei Zylindern mit durchgehender Kol-benstange oder bei kolbenstangen-losen Zylindern, der Zylinder in seine Ausgangsstellung zurückfährt

Volumen für einen vollen Rückhub

cylinder retract force (sec.)

Force generated by the cylinder during its instroke

force (f) en rentrée de tige

Time taken for the cylinder piston to instroke

temps (m) de course de

rentrée du piston d’un vérin

Temps mis par le piston du vérin pour rentrer

Zylinderrückhubzeit (f)

Zeit für einen vollen Rückhub des Zylinderkolbens

See cylinder cap end.

extrémité (f) sans tige d’un

vérin

Voir fond de vérin.

Siehe Zylinderbodenseite.

(pref.); cylinder neck

mounting (deprecated)

Mounting by means of a threaded projection coaxial with the cylinder axis at the rod end

fixation (f) par nez d’un vérin

Fixation par un prolongement fileté concentrique à l’axe du vérin et du côté tige

Gewindebefestigung (f), vorn

Befestigung an zentrischem deansatz auf der Kolbenstangen-seite

cylinder extend stroke (sec.)

Movement whereby a piston rod emerges from the cylinder body In the case of a through-rod or rodless cylinder, the movement away from the cylinder’s initial position

course (f) de sortie du piston d’un vérin (préf.); course (f)

d’extension du piston d’un

vérin (sec.)

Mouvement par lequel une tige de piston sort du corps d’un vérin Dans

le cas d’un vérin à tige traversante

ou d’un vérin sans tige, c’est le vement éloignant le vérin de sa posi-tion initiale

mou-Zylinder-Vorhub (m)

Bewegung, bei der eine Kolbenstange aus dem Zylinderrohr/-gehäuse ausfährt Bewegung, bei der, bei Zylindern mit

durchgehender Kolbenstange oder bei kolbenstangenlosen Zylindern, der Zylinder von seiner

Ausgangsstellung wegfährt

(pref.), cylinder extend force (sec.)

Force generated by the cylinder during its outstroke

force (f) en sortie de tige d’un

sortie de tige d’un vérin

Cylindrée correspondant à une course de sortie complète du piston

du vérin

Zylindervorhubvolumen (n)

Volumen für einen vollen Vorhub des Zylinderkolbens