Lesson 2_Formular One Car Design

8/14/2019 Lesson 2_Formular One Car Design

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AutodeskFormula Car Design 1

Lesson 2 Basic Part Design II

This lesson consists of creating three moderately challenging race carcomponents:

Wheel

Sprocket Front roll hoop

Objectives

After completing this lesson, you will be able to:

Revolve a sketch around an axis.

Create an offset work plane. Base a new sketch on a work plane.

Use the Project Cut Edges tool. Apply the Circular Pattern tool. Create and apply User Parameters.

Use Extrude with the Intersect option.

Exercise: Create a Wheel

In this exercise, you do the following:

Create the base sketch.

Make the rim cutout. Create the wheel spokes. Apply fillets and chamfers.

Completed Exercise


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Create the Base Sketch

In this sequence, you define a half cross section of the wheel and revolve itaround its center axis. It is recommended that you keep sketch geometry simpleto reduce the number of constraints to manage. For that reason, several filletsand chamfers are omitted from this base sketch. They can be added as features

later in the exercise.

1. Open a new metric part file.2. Set the Grid spacing to 100 mm.3. Start a new sketch on the YZ plane.4. Project the center point onto the sketch plane.5. Create a horizontal line and constrain it to the center point.6. Convert the line to a center line.7. Create and dimension the following sketch.

Note: An ordinate dimensioning scheme is used here for clarity.Sketches in parts use linear dimensions.

8. Revolve the sketch around the center line through a full 360 degrees.


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Make the Rim Cutout

The rim cutout is not strictly required for appearance sake since a tire will beplaced over the rim. However, modeling it enables you to determine the inertialproperties of the wheel. The cutout is created by revolving a sketch around thewheel axis using the Cut option.

1. Create a new sketch on the YZ plane.2. Press F7 to activate Slice Graphics.3. Use the Project Cut Edges tool.

4. Use the Project Geometry tool on the XY plane.5. Create the cutout sketch.


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6. Revolve the sketch using the Cut option.


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Create the Wheel Spokes

The wheel spokes are defined by cutting out a single opening and copying it withthe Circular Pattern tool.

1. Create a work plane 65 mm offset from the XZ plane toward the outside of

the wheel.

2. On a New Sketch, create the following on the work plane:

Draw two construction circles constrained to the origin, with diametersof 134 mm and 274 mm.

Constrain the outer arc concentric and equal to the 274 mm circle. Constrain the 16 mm inner arc tangent to the 134 mm circle.

Constrain the center of the 16 mm circle to be vertical with the centerpoint.

Constrain the left and right edges to be equal to one another.


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3. Extrude the sketch through all existing geometry with the Cut option usinga -3 degree taper. This taper reduces the size of the extrusion along itslength.


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4. Turn off the visibility of the work plane.5. Apply a 1 mm fillet to the inner and outer loop of the spoke cutout.

6. Use the Circular Pattern tool to create six copies of the spoke.


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Apply Fillets and Chamfers

In this sequence, you apply the fillets and chamfers to the wheel. Applying thesefeatures at the end of the modeling process helps retain sketch simplicity duringthe early modeling steps.

1. Apply a 3 mm fillet to the seven edges shown (three outer and four inneredges).


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2. Apply a 1 mm fillet to the three edges of the center nut opening.

3. Apply a 4 mm chamfer to the two edges of the centerbore.


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4. Apply fillets to the outer rim; a 3 mm fillet to the seven edges indicatedbelow and a 6 mm fillet to one edge.


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Examine the Tooth Profile

One half of the tooth profile is illustrated in bold as shown. It consists of thefollowing segments:

An arc of radius R from the midpoint of the tooth root to point v. Arc of radius E from v to x. This arc is centered at q.

Line from xto y.

Arc of radius F from y to z.

The input values required for calculating the parameters are:

Chain Pitch = 0.5 inch

Chain Roller Diameter = 306.0r

D inch

Number of teeth = 52N

The parameters are provided by the following equations, where the values are ininches.

003.0005.1 rs

DD

0015.0*3025.1 r

DE

3025.1))/64(17cos(4.1))/56(18cos(8.0( NNDFr

))/60(25cos(8.0 NDMr

))/60(35sin(8.0 NDTr

)/180cos(4.1 NDWr

22)*5.04.1( PitchDFH

r

)/180sin()/180cos()(5.0 NHNPitchS


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HDDNN

POD

rs2))(/180cos((

)/180tan(

Enter the Equations

The equations are entered in the Parameters dialog box. Several of the variablenames have to be modified because they conflict with the internal names forunits. For example, the variable S was changed to Sv.

1. Click Tools > Parameters.2. Click Add.3. Enter Pitch as the Variable Name.4. Set the Unit to inch.5. Enter 0.306 in the Equation field.

6. Continue entering the other equations. The equations can be entered inany order.

Model the Tooth

1. Start a new sketch on the XZ plane.2. Create a sketch of a half tooth using the parameters shown.


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3. Extrude the half tooth profile using the Midplane option.


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Complete the Teeth

In this sequence, you replicate the teeth and shape their tip.

1. Mirror the half tooth about its right face.

2. Use the Circular Pattern tool to replicate the tooth 52 times around thesprocket.

3. Create a new User Parameter named OD2 using the equation:

)/180tan(

16.02

NPitchOD .

Note: Remember the parameter names were slightly modified so as notto conflict with unit names. In this case, N corresponds to Nt.

4. Create a new sketch on the XZ plane.


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5. Create a circle constrained to the origin.6. Dimension the circle to a diameter of OD2.

7. Extrude the circle using both the Midplane and Intersect options.

8. Create a new sketch on the YZ plane.9. Press F7 to activate Slice Graphics.10. Project the top line of the tooth and create a sketch to trim the sides.


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11.Revolve the sketch around the sprockets center axis using the Cut option.


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Add the Mounting Holes

1. Create a new sketch on the side of the sprocket.2. Create a construction circle 110 mm in diameter.

3. Create a center point and constrain it horizontal to the origin andcoincident with the construction circle.

4. Use the Hole tool to create a 10 mm diameter hole located on the centerpoint.


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5. Use the Circular Pattern tool to make eight holes centered on the sprocketaxis.

6. Use the same method to create a circular pattern of four 11 mm diameter

holes located on a 149 mm construction circle.


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About Roll Hoops

Race cars typically require a roll structure behind and in front of the driver; with

these in place, if a rollover occurs, the driver is protected from the road surface.

Exercise: Create a Front Roll HoopIn this exercise, you do the following:

Define a cross section. Create a sweep path.

Perform a sweep.

Define Cross Section

1. Open Frame.ipt.2. Create a new sketch plane on the upper surface of the square tubing.


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3. Create a 25 mm circle and add tangent constraints to the rear and sideedges.

4. Finish the sketch.


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Create the Sweep Path

1. Click the Work Plane tool. The work plane is defined as parallel to the XZplane and passing through the center point of the cross section circle.

2. Click on the XZ Plane within the Origin folder, and then click the center ofthe circle.

3. Define a new sketch on the work plane.4. Project the center point of the circle onto the sketch plane.5. Create a line, arc, and a second line starting from the circle center point.6. Constrain the end of the horizontal line coincident with the edge of the

horizontal tube.


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7. Finish the sketch.

Perform Sweep

1. Click the Sweep tool.2. Click the path which was just created.


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Completed Roll Hoop

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Lesson 2_Formular One Car Design