Wheel Assembly Proj Inf

AutoCAD Drawing Unit


Wheel Assembly Drawing Project

Learning Objectives

Develop sketching and planning skills for the production of a mechanical component.

Develop technical literacy and vocabulary related to the drafting conventions and manufacturing.

Develop a working knowledge of AutoCAD in both 2 dimensional and 3 dimensional drafting formats.

Create 2 dimensional orthographic views to describe an object exactly and completely for manufacturing purposes.

Develop computer literacy related to the graphics industry and manufacturing.

Create an assembly drawing and parts list.

The Wheel Assembly - shown with wheel in section.



Project Process

1) Sketching refer to your notes and the information page for the Wheel Assembly to create freehand orthographic sketches of each of the parts on the sheets provided. Follow the standard engineering sketch layout format. Please print answers to the questions for each part in the spaces provided.

Sketches:

Must show the correct number of views of each part in their proper

orthographic order.

Are to show the 3 overall dimensions for each part in the sketches. (length, width & height)

Are to be done in pencil, are large and clear and include your name and the date.

Include labels showing all part names.

Are to be handed in prior to starting the CAD drawings.



Part #1 Base Plate

Name: _____________

Answer the questions below and provide the orthographic sketches on the back of this sheet. Follow the criteria and checklist given in previous notes for your sketch format.

1. What material is the base plate made of, and how and why has it been abbreviated?

2. The base plate has 4 rounds. Explain what a round is, why it may have been used in this application, and list the size used.

3. What is the purpose of the 4 holes and what are their size(s)?

4. How is the size of all 4 holes indicated and why?

5. Base Plate length = _____________

(overall

Base Plate width = _____________

dimensions)

Base Plate height = _____________

6. How far in from both corners are the holes located?

7. How deep are the notches at the top and recesses at the bottom?

8. What is the purpose of the recesses at the bottom of the base plate?


Wheel Assembly Drawing Project9. Not all of the features of the base plate will be visible on each of the views. How are features that are not visible shown? Sketch the line used to show these features.

10. The base plate is by its shape, is referred to as non-cylindrical view. Write the definition of a non-cylindrical object below. How many orthographic views are possible, and how many are usually drawn? Name the views that are normally drawn.

11. Base Plate Orthographic Sketches - Sketch the views you will

draw in AutoCAD. Show the views in their proper order, label

each view, provide the overall dimensions of each view and

show hidden lines and centerlines if any.

Base Plate sketches



Part #2 Wheel

Name: _____________

Answer the questions below and provide the orthographic sketches on the back of this sheet. Follow the criteria and checklist given in previous notes for your sketch format.

12. What material is the wheel made of, and how and why has it been abbreviated?

13. The wheel has both rounds and fillets. Explain what both a round and fillet are, why they may have been used in this application, and list the size(s) used.

14. What is the purpose of the hole and what is its size?

15. What does the symbol represent?

16. How thick is the center web that connects the axle support

to the outer wheel?

____________________________________________________

17. How thick is the wheel at its outside edge?

18. How thick is the wheel at the inner web?

19. Suggest a reason for the difference in the thickness of the outer wheel.


Wheel Assembly Drawing Project20. Wheel Orthographic Sketches - Sketch the views you will




Wheel Sketches



Part #3 Bracket

Name: _____________

21. What material is the bracket made of, and how and why has it been abbreviated?

22. Some of both the inner and outer edges of the bracket have been rounded. Name the features and indicate what radius these are to be drawn at.

23. One of the secondary machining processes on the bracket is labeled as 2 x 10 - 15 SFACE. What is the name of this process and why is it done?

24. The small triangular shape placed between the two main parts of the bracket is called a ____________. Its main purpose is to provide _______________________________.

25. The raised circular area on the inside face of the brackets is called a ____________. Its main purpose is to provide ________________________________________________


Wheel Assembly Drawing Project26. Bracket Orthographic Sketches - Sketch the views you will




Bracket sketches AutoCAD Drawing Unit


Part #4 Axle

Name: _________________

27. What material is the axle made of, and what does this code stand for?

28. The axle has steps on each end. Why is it a larger diameter in the center?

29. The axle has a secondary machining process applied to each end (edge) of it. The process is part of the general notes on the drawing sheet. Name the process and explain why it has been applied to the ends of the axle.

30. The axle is classified as a cylindrical object. How many orthographic views are possible, and how many are drawn?


Wheel Assembly Drawing Project31. Axle Orthographic Sketches Sketch the views you will




Axle Sketches



This project is designed to introduce mechanical drafting and design while developing computer literacy through the use of one of the most widely used computer aided drafting and design programs AutoCAD.

The wheel assembly is a fairly typical, fixed wheel type caster made up of 4 parts that would be bolted or riveted to another object.AutoCAD Drawing Unit


Dimensioning Non-Cylindrical Objects

Before you add the dimensions to your orthographic CAD views of the base plate and the brackets, complete the assignment and reading. Reference: Fundamentals of Technical Drawing, by Norman Stirling pages 70-82.

32. Why are technical drawings dimensioned?

33. Name the two methods of dimensioning technical drawings and explain the difference between the two.

34. Name the two types of dimensions every object has, and explain what the difference between them is.

35. List 10 basic dimensioning rules. (Pg 74-78)



Dimensioning Cylindrical Objects

Before you add the dimensions to your orthographic CAD views of the axle and the wheel, complete the assignment and reading. Reference: Fundamentals of Technical Drawing, by Norman Stirling pages 85-91.

36. Cylindrical holes and radii are dimensioned where their shapes are shown as __________ or ____________.

37. The PHI symbol () is used to indicate _________________.

38. What is the purpose of a leader line?

39. List 4 rules to follow when drawing a leader for a cylindrical hole.

40. How is a semicircular exterior feature dimensioned?

41. Why are notes often used to dimension rounds & fillets?



Sectional Views

Once you have created dimensioned orthographic CAD views of the axle and the wheel you may find that there are areas where all the detail cannot be seen or dimensioned clearly as they can only be seen as hidden lines. Section drawings are introduced to help describe the shapes of complicated interior features. In this project you will create a half sectional view of the orthographic (2d) wheel and a full section of the complete assembly as a 3dimensional model. Complete the assignment and reading prior to beginning these drawings. Reference: Fundamentals of Technical Drawing, by Norman Stirling pages 156-172.

42. Why are sectional drawings made?

43. What is a full sectional drawing?

44. What is a half sectional drawing?

45. What is an offset sectional drawing?



Sectional Views make a half sectional view of the wheel. In a half section, of a cylindrical object is imagined to be removed.

To create the orthographic (2d) half sectional view of the wheel:

a) Copy the side view of the wheel you have previously drawn and place it adjacent to the original view.

b) Erase all dimension lines and notes.

c) Change all the hidden lines (only from the center line up), to object lines.

d) Remove any of the hidden lines below the center line.

e) Add dimensions to the lines that were previously hidden in the top half of the wheel, and were not shown on the original drawing.

f) Hatch the portion of the wheel that shows the imaginary cut. Select the hatch pattern that matches the material the wheel is made of.

Original orthographic view (l) and section view (r)



Creating 3d models of the wheel assembly parts

There are many methods of creating 3d models of components. In this exercise you will use the previously created 2 dimensional views as a basis for creating the models.

a) Copy each of the finished orthographic drawings and resave them with a new filename (base plate model etc.)

b) Open the base plate and delete the top view, the side view, and all the dimensions, hidden lines, and center lines on the front view. This remaining view will form the basis of the model.

c) You will be using the extrude command to transform the remaining front view into a 3d model. At present, it is a series of individual lines. Use the pedit command (keyboard or icon) to join all the lines into one continuous line.

type pedit (no quote marks)

select plotline or [multiple]

type m for multiple and drag a box around the base plate outline

convert lines and arcs to plotlines [yes/no] -press enter to accept

enter an option type j to join the lines

enter the fuzz distance or [join type] -press enter to accept default settings

press enter to finish/end the pewit command

d) The outline should now be one continuous line. Prove it to yourself by moving the object by selecting only one of the line. The rest should move with it.

e) If the view menu bar is not on, you can turn on the view menu bar by right clicking any of the menu bars ands selecting view. Select the SE Isometric icon.f) Select the extrude icon and extrude the base plate to the required width. (if the extrude icon is not present on your screen follow the method in (e) above to locate and turn on the appropriate menu/icon group.(g) The extruded base plate. The next

step will be to fillet the corners and add

the 4 holes.

Commands:fillet select one of the

Edges to be filleted.

enter fillet radius as given

enter to finish the process

repeat for the remaining corners.

Draw a circle for one of the holes.

Extrude the circle as required.

Rotate the cylinder 90

Copy the cylinder from its center point to the center of the fillet. Repeat for the remaining holes.

(h) Use the subtract command to remove the holes from the base plate. Select the base plate first, right click, then the 4 holes. Right click to finish the command.

(i) The last step will be to rotate the base plate so that the top view

icon displays the top view of the object.

Commands:modifyrotate 3dspecify an axis to rotate

onrotate by 90 increments. Select the front view icon the

displayed object should show the front view. The top should

now display the top, etc.

EMBED PBrush

Documents

Wheel Assembly Proj Inf