Banh Rang Ngieng

7/31/2019 Banh Rang Ngieng

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ME-430 INTRODUCTION TO COMPUTER AIDED DESIGN

Helical Gear using Surface FeaturesPro/ENGINEER 2001

Dr. Herli Surjanhata

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

Create gear parameters by

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

Enter diametral_pitch P

Enter a value of8

Continue to create the following parameters:

Parameter Type Value Description

N Integer 39 No of teeth

AGMA_quality Integer 10

tooth_form String 20 DEG INV


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AGMA

Full-Depth

PA Real Number 20.0 pressure_angle

Create relations for the gear parameters. From Part menu, select

Relations -> Add

Enter the following:

DP = N/P

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 informationwindow.

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


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Select Edit Rel and add the following relations:

d0 = DA

d1 = FW

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.


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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.

INVOLUTECURVE


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Create a second datum curve for the root of the tooth.


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 involutedatum 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 alignedwith the centerlines. The arc should lie inside the datum curve.

see Figure below.

Create a diametral dimension for the arc.

Second centerline

First centerline


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

From Sketch pull-down menu, select Relation.

Sketch thisline!


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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 themodel 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.


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Pick thelowest

point asshown on

the left.

Done

The resulted curve is shown onthe left.

Add helix angle as a new parameter.

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

angle)

-> 20 -> -> Done.

Create a sweep trajectory datum curve



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From Equation -> DonePick 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


Sketch -> DonePick the RIGHT datum plane as sketching plane.

OkayTop -> Pick the TOP datum plane

Pick the right face of the cylinder as an additional reference.


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Sketch a straight line on the datum axis.


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.Done Sel -> Done -> Done

Open Ends -> Done

Sketch this horizontalline.


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Use this icon select

Loop, and pick each of thethree curve segments needed

for surface.

From Sketch pull-down menu, selectReferences

Sweep

trajectory

Normal

trajectory


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Select all the references in the referencewindow.

Delete -> Close


Copy the cutting surface

From Insert pull-down menu, select

Surface Operation -> Transform

Move -> Copy -> DonePick the surface just previously created

Done SelRotate -> CSys

Pick the INVOLUTE_CSYS

Z axis

Okay

Type in: 360/N

Done Move


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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


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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 dimensionas 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


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The resulted gear is shown below:

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Banh Rang Ngieng