how to make splines

8/13/2019 How to Make Splines

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How to Make Splines

Creo Parametric 2.0

S.F DunkerJuly 18, 2013

The existing component was modified to have a root diameter of 1.418

Figure 1

Create a csys where xand yare used to create the involute curve and zis the axis of the shaft. The

sketching plane will be on the end of the shaft.

Figure 2

Create four circles for the outside, pitch, basic, and root diameters. Previous features were suppressed for

clarity.


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Figure 3

Create the involute curve by equation by entering the following equations where ris the radius of the base

diameter. Select the csys created in Figure 2.

Figure 4

The involute curve is shown in Figure 5. It starts from the intersection of the base diameter and top

datum plane.

r = 1.446/2

ang = t * 90

s = (PI * r * t)/2

xc = r * cos(ang)

yc = r * sin(ang)

x = xc + (s * sin(ang))y = yc - (s * cos(ang))

z = 0

OD = 1.550

RD = 1.418 min

BD = 1.446

PD = 1.500


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Figure 5

Create a set of datum points, one at the intersection of the involute curve and the pitch diameter, the other

one at the csys. Connect the two points with a datum curve.

Figure 6

Measure the angle between the curve created in Figure 6 and the top datum plane. The angle is 0.433783


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Figure 7

Sketch two datum points on the spline_sketch_dtm and pitch diameter to represent the thickness of a

single gear tooth. The average tooth thickness, (0.0768 + 0.0755)/2 = 0.07615, was used.

Figure 8

Sketch one curve between PNT3 (tooth pitch point) and the csys, then sketch another curve 0.433783 off

the first curve, intersecting the pitch diameter and the csys.


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Figure 11

Copy the involute curve, then paste special. Apply move/rotate transformation to copies. Pick the z axis

and enter 86.6563. Figure 16 is the result.

Figure 12: Copy


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Figure 13: Paste Special

Figure 14: Apply Move/Rotate


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Figure 15: Rotate/Z Axis Selection

Figure 16: Rotated Involute


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Zoom in and confirm that the rotated involute passes through PNT3 and starts from the base diameter

Figure 17

Mirror the rotated involute about the front plane.

Figure 18


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The involute curves are symmetrical about the front plane. This is required according to the drawing.

Figure 19

Sketch the tooth using pick edge and use tangent constraints.

Figure 20


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Extrude the tooth.

Figure 21

Add chamfers and radii, and then group all features for the tooth.

Figure 22


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Pattern the group according to Figure 23. Divide 360 by the number of teeth: 360/30 = 12. This is the

angle between teeth centers.

Figure 23

Splines should look like Figure 24.

Figure 24


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Create cut for other chamfer and radius.

Figure 25

Finished product.

Figure 26


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Top and bottom teeth are symmetrical about the front plane, according to drawing section a-a.

Figure 27

how to make splines

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