Bài tập thực hành bảo dưỡng và sửa chữa cơ khí ô tô

Tài liệu là tuyển tập các bài tập thực hành dành cho sinh viên thực tập bảo dưỡng và sửa chữa cơ khí ô tô, có giải thích rõ các nhiệm vụ (task) và yêu cầu của bài thực hành. Tài liệu có thể làm tài liệu tham khảo cho các giáo viên dạy nghề ô tô xây dựng các bải thực hành phù hợp cho sinh viên.

STUDENT WORKBOOK Version: August 2011

 This workbook is a major component of the assessment for this competency, all

Questions and Projects, MUST BE COMPLETED and signed off by your teacher

 It is the student’s responsibility to complete the Assessment Requirements, listed in this workbook and to ensure that teachers progressively sign off requirements as

they are completed (Teachers must not sign off work they have not witnessed

completed)

 When completed the “Assessment Outcome” (above) is to be signed by your teacher

 This workbook is to be retained by the student as their record of the completion of this competency

MEM18007B

Unit Name:

Maintain and repair mechanical drives and mechanical transmission assemblies

Assessment Requirements

Assessment/Project Date Teacher’s Signature

“Student Safety Requirements for Workshops”

– Form Signed

1 – V-Belt Drives Project

2 – Chain Drives Project

3 – Worm / Worm Wheel Gearbox

(Using Dial Indicator)

7 – Colchester Lathe - Headstock / Gearbox

8 – Colchester Lathe – Clutch Assembly

9 – Workbook / Assessment Questions

10 – Tools Cleaned & Returned

Work Areas Tidy (Housekeeping)

11 – Theory Examination

Contents

Section 1: Unit of Competency 5

Competency Descriptor 5

Competency Unit Resources 8

Assessment Strategies 9

Typical Lesson Schedule 10

Section 2: Assessment Tasks 11

Assessment Task No1 11

Assessment Task No2 17

Assessment Task No3 34

Assessment Task No4 35

Assessment Task No5 40

Assessment Task No6 42

Assessment Task No7 44

Assessment Task No8 58

Assessment Task No9 60

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Section 1: Unit of Competency

Competency Descriptor

Unit descriptor This unit covers diagnosing faults and repairing drives and transmission

assemblies, and undertaking final adjustment and commissioning

Prerequisites MEM09002B Interpret technical drawing

MEM12023A Perform engineering measurements MEM18001C Use hand tools

MEM18002B Use power tools/hand held operations MEM18003C Use tools for precision work

MEM18006B Repair and fit engineering components MEM18009B Perform levelling and alignment of machines and engineering components

MEM18055B Dismantle, replace and assemble engineering components

Competency field Maintenance & diagnostics

Application of the competency This unit applies to diagnostics and maintenance, repair, adjustment and commissioning of mechanical drives and mechanical transmission assemblies

Band A

Unit Weight 4

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Competency Unit Resources

No text book has been set for this competency

However, there are many books that cover "Fitting and Machining" in the Institute Library

You are able to access these at any time

Reference Resources:

Fitting and Machining, Culley, Ron ED., 1996, TAFE Publications, Collingwood, Vic

Principals of Machine Maintenance, Dick Jeffrey (Yeronga Lib No - TJ 1040 J43 1991)

Basic Training Manual: Workshop Safety, 1999, Australian Training Products Ltd, Melbourne Basic Training Manual: Hand and Power Tools, 1999, Australian Training Products Ltd,

Melbourne

Machine Shop Technology Vol 1, Maskiell & Galbraith, 1984, McGraw-Hill Book Company

Engineering Drawing Handbook, The Institution of Engineers Australia.. (Lib No - T 357.E53 1993)

Australian Standards: AS1100 - Technical drawing

AS1101 – Graphical symbols for general engineering AS1654 – Limits and fits for engineering

Video: Vee Belts (not sure of actual title) TJ1100 V2 1995

Practical Exercises Assignment Presentation

Assessors should gather a range of evidence that is valid, sufficient, current and authentic Evidence can

be gathered through a variety of ways including direct observation, supervisor’s reports, project work, samples and questioning Questioning techniques should not require language, literacy and numeracy skills beyond those required in this unit of competency The candidate must have access to all tools, equipment, materials and documentation required The candidate must be permitted to refer to any relevant workplace procedures, product and manufacturing specifications, codes, standards, manuals

and reference materials

Typical Lesson Schedule

(This typical lesson schedule will be followed as closely as possible throughout the competency; however changes may occur to suit circumstances )

1 Self paced / Flexible block delivery

2 Self paced / Flexible block delivery

3 Self paced / Flexible block delivery

4 Self paced / Flexible block delivery

5 Self paced / Flexible block delivery

6 Self paced / Flexible block delivery

7 Self paced / Flexible block delivery

8 Self paced / Flexible block delivery

9 Self paced / Flexible block delivery

10 Self paced / Flexible block delivery

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Section 2: Assessment Tasks

Assessment Task No1

V-BELT DRIVES

Instructions

TASK

To check a V-belt set for wear then- to refit & re-tension the v-belts

1 Loosen the tension adjustment screws

2 Remove the v-belts

3 Loosen and remove the belt pulleys

4 Refit, align and tension the V-Belts –

(see information on following pages)

5 See your instructor when fitting is complete

Six Simple Rules for Tensioning V-Belts

The tension of the belts on a V-belt drive is usually not critical A few simple rules will satisfy most requirements

1 The best tension for a V-belt drive is the lowest tension at which the belts will not slip under the highest load condition

2 Check the tension frequently during the first day of operation

3 Check the tension periodically thereafter

4 Too much tension shortens belt and bearing life

5 Keep belts and sheaves free of any foreign material which may cause slip

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Assessment Task No2

CHAIN DRIVES

Instructions

Project Task - Check a chain for wear and then refit & re-tension the chain to

correct operating tension

1 Loosen chain tensioner locking nut

2 Back of adjusting nuts for the chain

3 Remove Chain joining link Remove chain

4 Place chain on the anchor hook on the work bench (Use a “G” clamp to anchor the

chain to the work bench)

5 Check chain for wear - (see information on following page)

6 Refit & re-tension the chain - (see information on following pages)

7 Check with your teacher on completion of this task

Chain Drives Project Check List Completed - Teachers’s Initials / date / times

Task 1 Complete Chain Theory Assignment (In Workbook) Start time & Date

Task 2 View videos as directed by your teacher

Task 3 View the On-Line presentation

Task 4 Make-up a tool list (In Workbook)

Task 5 Complete Disassembly questionnaire (In Workbook)

Questions are also on the slide show

Task 6 See your teacher before starting the job

Task 7 Completed project - to be inspected by your teacher Finish time & Date

View the On-Line presentation

See Your Teacher Now!

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Task 4

Project tool List 

Note:- Complete the tool list as you are working through the project slide presentation

Tools needed - to complete the chain project

Task 5

Disassembly Questionnaire

Q1 Is the chain a Duplex; simplex or triplex chain

Q2 How is the joining link spring clip removed from the chain

Q3 What action could be taken to prevent the spring clip from propelling across the

workshop and being lost?

Q4 When checking the chain for stretch how is the chain secured

Q5 How many links are you counting out to measure the chain stretch?

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Q6 How many dimensions are required to identify a chain

Q7 From the charts in your workbook, use the dimensions taken to find the Reynolds Chain

Q9 When refitting the chain to the sprockets where should the ends of the chain meet?

Q10 When fitting the spring clip to the joining link in which direction should the open end be

facing?

Q11 State the formula for determining correct chain tension

Q12 When adjusting the sprocket for chain tension, what sequence would you use?

(circle one)

(1) Tighten the sprocket nut the turn the adjusting nuts until the correct tension is achieved

(2) Lightly take up the sprocket nut, then turn the adjusting screws until the correct tension is

reached, then tighten the sprocket nut

(3) Turn the adjusting nut until the correct tension is achieved then tighten the sprocket nut  

Task 6

Start the project job

See Your Teacher Now! (Before Starting the Job)

Working…Working…Working…

Task 7

Completed the job?

See Your Teacher Now!

(Your teacher must inspect the completed job)

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Assessment Task No3

REDUCTION GEAR BOX

Instructions

BOTTOM SHAFT END PLAY (Reduction Gear Box)

1 Remove bolts from Top End Covers Remove End Covers and Shims

2 Remove bolts from Top Half Casing

3 Using Crane lift off Top Half Casing

4 Using Crane and Lifting Hooks, remove Worm Wheel

5 Position Dial Test Indicator on the gear box housing so that the pointer is on the end of the shaft

6 Remove fan coupling

7 Pull on shaft and note any needle deflection

8 Add or subtract shims to achieve desired End Play, set by your teacher

(Always ensure that bolts are tightened to correct torque – see chart supplied)

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Assessment Task No4

REDUCTION GEAR BOX

WORM TO WORM WHEEL CONTACT PATTERN

1 Remove bolts from Top End Covers Remove End Covers and Shims

2 Remove bolts from Top Half Casing

3 Using Crane lift off Top Half Casing

4 Using Crane and Lifting Hooks, remove Worm Wheel

5 With a Rag, clean all worm wheel teeth

6 Smear Bearing Blue evenly over Worm

7 Using Crane place Worm Wheel back into Gear Box housing

8 Centralise the Worm Wheel using shims

9 Rotate the input shaft (bottom shaft) clockwise

10 Check blue pattern on back of Worm Wheel Teeth –

(See information on following pages)

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Assessment Task No5

COUPLING ALIGNMENT

Using Feeler Gauges and Straight Edge

1 Loosen motor holding down bolts, remove all shims, then check with your instructor

2 Place shims under motor holding bolts until coupling flanges are in alignment

3 By use of the adjusting bolts on the sides of the motor bring flanges into horizontal

alignment

Note:

 Viewed from the SIDE: flanges should be free from angular misalignment

and parallel misalignment

 Viewed from the TOP: Flanges should be free from angular misalignment

and parallel misalignment

 Alignment must not be accomplished by manipulating the tension

applied to the holding down bolts:

 A Medium to Light hand tension is to be applied at all times

There are absolutely no exceptions

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Assessment Task No6

COUPLING ALIGNMENT

Using a Dial Indicator

1 After completing the coupling alignment, using the feeler gauges

2 Fit a Dial Indicator to the coupling and check for any mis-alignment

3 Adjust any mis-alignment to within 0.05mm

Note:

a Viewed from the SIDE: flanges should be free from angular misalignment

and parallel misalignment

b Viewed from the TOP: Flanges should be free from angular misalignment

and parallel misalignment

c Alignment must not be accomplished by manipulating the tension

applied to the holding down bolts:

d A Medium to Light hand tension is to be applied at all times

There are absolutely no exceptions

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Assessment Task No7

Colchester Lathe - Headstock Instructions

1 You, (and a partner), will be allocated a lathe headstock

2 Remove any covers

3 Examine the headstock, and drawings

4 Determine how you are going to commence disassembly

5 Discuss this plan with your teacher BEFORE you commence

6 Disassemble the headstock

 You are to remove all shafts, bearings, gears, linkages, clutches, etc

 Be careful & take notes and/or photos, of the order in which the

components are removed, as reassembly can only occur in the reverse order

 Layout & mark each component to assist you in the reassembly

NOTE:

This project is about developing GOOD fitting techniques, it is not a race, we

expect that this will take a number of days to complete

DO NOT use any tools or techniques that will damage the components, if you are not sure how to do something? – Then ask your teacher

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7 While the gearbox is disassembled;

Answer the following questions

Q1 What type of gears are used in the headstock?

- Spur gears? How many? _

- Helical gears? How many? _

- Bevel gears? How many?

Q2 Examine the bearings:

List the types of bearings & number of each type of bearings used in the headstock, use the correct names;

Q3 Will any of the bearings carry any THRUST LOAD, when the lathe is in operation?

Which ones if any _

What type of bearings are they? _

8 Re-assemble the gearbox

NOTE:

 Make sure that you don’t have any spare parts left after assembly!

 All linkages and speed ranges must operate correctly

 Repair any parts that are missing or damages to ensure that the headstock functions correctly, (as if it was going back into service)

9 Your teacher must inspect and sign-off your completed work

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Assessment Task No8

Colchester Lathe - Clutch Assembly Instructions

1 Examine the Colchester lathe clutch shaft & drawings

(This is best completed while it is disassembled)

2 Complete the following;

Q1 There appears to be more than one clutch, or clutch pack, is this

When your teacher is available, you are to fully describe & explain the

operation of, and adjustment of, the clutches

Teachers use

Verbal description & explanation

completed DATE

Teacher signature

Assessment Task No9

Friction Belt Drives

Describe the main difference between a Double vee-belt and the narrow and classical vee-belts

Explain why it is necessary to ensure a correct key fit when installing taper lock hubs with a pulley

Gears & Gear Drives

A gear train consists of sis gears give rations of 4:1, 3:1, and 5:` What is the overall ratio

achieved by the gear train?

(a) What is the overall ration of the gear set

(b) If the input pinion has a RPM of 875, what is the output PPM of the gear train

Clutches, Brakes & Couplings

Describe the correct procedure for preparing a coupling for installation

List the three main categories of brakes

List the three main types of alignment encountered when aligning pulley