Tài liệu Helical Gear – using Surface Features Pro/ENGINEER pdf

Done -> Regenerate Rename the coordinate system, Set Up -> Name, pick the coordinate system and enter the new name involute_csys Create a datum curve for the involute tooth profile.. I

ME-430 INTRODUCTION TO COMPUTER AIDED DESIGN

Helical Gear – using Surface Features

Pro/ENGINEER 2001

Dr Herli Surjanhata

Create a one side solid protrusion for base feature of helical involute gear as shown below:

Create gear parameters by

Set Up -> Parameters -> Part -> Create -> Integer

Enter diametral_pitch P Enter a value of 8

Continue to create the following parameters:

Parameter Type Value Description

tooth_form String 20 DEG INV

– AGMA Full-Depth

Create relations for the gear parameters From Part menu, select

Relations -> Add

Enter the following:

or

pitch_dia_gear = no_gear_teeth/diametral_pitch

Hit Enter key twice

Select Edit Rel and enter the following relations with a text editor

A = 1/P addendum = 1/diametral_pitch

B = 1.25/P dedendum = 1.25/diametral_pitch

DA = DP + 2 * A outside_dia_gear = pitch_dia_gear +

2*addendum

DD = DP – 2 * B root_dia_gear = pitch_dia_gear -

2*dedendum

DB = DP * COS(PA) Base_gear_dia = pitch_dia_gear * cos

(pressure_angle)

CP = PI/P circular_pitch = pi/diametral_pitch

FW = 3 * CP Face_width

Save the file and exit the editor

Select Show Rel to view parameters and verify the relations Close the information

window

Select Relations and pick the protrusion Note the diametral dimension e.g ∅d0

Select Edit Rel and add the following relations:

theta_4 = 360/(2*N)

theta_1 = 360/(4*N)

phi_p = sqrt((DP/DB)^2-1)

theta_2 = 180/pi*phi_p - atan(phi_p)

theta_3 = theta_4 - theta_1 - theta_2

alpha = theta_2 + theta_1

Save the file and exit the editor

Done -> Regenerate

Rename the coordinate system,

Set Up -> Name, pick the coordinate system and enter the new name

involute_csys

Create a datum curve for the involute tooth profile

Select the Create Datum Curve icon

From Equation -> Done

Pick the INVOLUTE_CSYS -> Cylindrical

The text editor appears, and enter the following equations:

phi=t*sqrt((DA/DB)^2-1)

r=0.5*db*sqrt(1+phi^2)

theta=(180/pi*phi-atan(phi))-alpha

z=0

File -> Exit -> Yes

Preview the curve and select OK

INVOLUTE CURVE

Create a second datum curve for the root of the tooth

Select the Create Datum Curve icon

Sketch -> Done

Pick datum FRONT for the sketching plane and datum TOP for the TOP reference

In addition to the default references, carefully pick the inside endpoint of the involute datum curve

Sketch a center line through the INVOLUTE_CSYS and create an angular dimension

from datum TOP

Sketch a second centerline through the INVOLUTE_CSYS that is also aligned to the

inside end point of the involute datum curve

Use the Arc, Center and Ends icon to sketch an arc with the center aligned to the coordinate system, and the ends aligned with the centerlines The arc should lie inside the datum curve

– see Figure below

Create a diametral dimension for the arc

Second centerline

First centerline

Use the Line icon to create a line from the inside point of the involute datum curve to the arc

From Sketch pull-down menu, select Relation

Sketch this line!

Select Add Enter the following relations:

sd1 = theta_4

sd3 = DD

Pick the , and then click the OK button

Mirror the involute profile consisted of 2 datum curves previously created

Feature -> Copy

Mirror -> Select -> Dependent -> Done

Select the two datum curves from the model tree

Done Sel -> Done

Make Datum -> Through

Select the datum axis A_1 from the model

Through -> Point/Vertex – make sure Point/Vertex is highlighted, and the rest (e.g AxisEdgeCurv, Plane, Cylinder) is unchecked

Pick the lowest point as shown on the left

Done

The resulted curve is shown on the left

Add helix angle as a new parameter

Setup -> Parameters -> Part -> Create -> Real Number -> beta (for helix angle)

-> 20 -> -> Done

From Equation -> Done

Pick the INVOLUTE_CSYS

Cylindrical

Type the following equations in the editor

File -> Exit -> Yes

Preview the curve and select OK

Create a normal trajectory datum curve

Select the Create Datum Curve icon

Sketch -> Done

Pick the RIGHT datum plane as sketching plane

Okay

Top -> Pick the TOP datum plane

Pick the right face of the cylinder as an additional reference

Sketch a straight line on the datum axis

Pick the , and then click the OK button

Create a new variable section sweep surface Select

From Insert pull-down menu, select

Surface -> Variable Section Sweep

Norm To Traj -> Select Traj

Pick the sweep trajectory as the origin trajectory

Done Sel -> Done

Use Norm Traj -> Done

Select Traj – Pick the normal trajectory curve

Sketch this horizontal line

Use this icon select

Loop, and pick each of the three curve segments needed for surface

From Sketch pull-down menu, select

References

Sweep trajectory Normal

trajectory

Select all the references in the reference window

Delete -> Close

Pick the , and then click the OK button

Copy the cutting surface

From Insert pull-down menu, select

Surface Operation -> Transform

Move -> Copy -> Done

Pick the surface just previously created

Done Sel

Rotate -> CSys

Pick the INVOLUTE_CSYS

Z axis

Okay

Type in: 360/N

Done Move

Insert -> Cut -> Use Quilt

Query select the transformed surface

->

Group the cutting surface and cut

Feature -> Group -> Cancel the Open window

Local Group

Type in: cut

Select the last two features (transformed surface and cut from the model tree)

Done Sel -> Done

Pattern -> Pick the Group CUT from the Model Tree

Click on dimension 9.2°

Type in: 360/N

Done

Done

Create a coaxial hole of 1.2 inches diameter for the shaft

Create a chamfer 45° x d with d = 0.05 at the both sides of the hole

Create a cut for the keyway with the dimension

as shown on the left

Hide the datum curves and surface

Select the curves and surface in the model tree, right click mouse button, and select Hide

The resulted gear is shown below: