1 Driving-Pulley, 3 Driven-Pulleys, 2 Belts

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Navigation:  Getting Started Tutorials - MechDesigner > Tutorial 17: Belts and Pulleys > Step 17.2: Option 1 - Fixed Pulley Centers >

1 Driving-Pulley, 3 Driven-Pulleys, 2 Belts

Fixed Pulley centers : Two or more Pulley Sets

GST-TwoPulleysSets

Use Two Belts to:

•Give a larger speed reduction

•More flexible ratios.

The image to the left is a schematic with:

•Three shafts

•Two belts

tog_minus        Step 1:  First Belt

Add Motion-Path of Belt 1 and two Rockers

GST-17-1-Option1-BbyP-0

STEP 1: Add a closed sketch-path to represent the path of the belt.

1.Edit the Base-Part :

Add a sketch-path to represent the path of a BeltRed-14-1. In this example, the sketch-path has two Arcs and two Lines.

Click Add Dimension : Click each Arc Red-14-2. The radius of each Arc is not important.

Click Add Dimension Click the center-Points of the ArcsRed-14-3. The distance between the Arcs is not important

2.Exit the Part-Editor

STEP 2: Add a Line to the sketch

1.Edit the Base-Part

Click Add Line - drag in the graphic-area to add the LineRed-14-4.

Click Add Coincident Constraint : Click the start-Point of the Line and the center-point of an Arc.

Click Add Horizontal Constraint : Click the Line

Click Add Dimension : Click the Line

2.Exit the Part-Editor

GST-17-1-Option1-BbyP-1

STEP 3: Add a Motion-Path FB

1.Kinematic FB toolbar > Add Motion-Path FBRed-14-5

Click one of the sketch-elements in the sketch-path that represents the belt.

Click OK-tiny-13-17 in the Command-Manager

A Motion-PointRed-14-6 is at the start-Point of the sketch-element that you select.
GST-17-1-Option1-BbyP-2

STEP 4: Add the Parts for the Pulley's

1.Add Part × 2: × Drag to add the two PartsRed-14-7. The length of each Part is not important.

2.Add Pin-JointRed-14-8: Click the start-Point of a PartRed-14-7 and the start-Point of the LineRed-14-4 .

3.Add Pin-JointRed-14-9: Click the start-Point of the other PartRed-14-7 and the center-Point of the other Arc.

4.Add Motion-Dimension FBRed-14-10a : Click the Pin-JointRed-14-8 ; Click the LineRed-14-4 ; Click the CAD-Line along the PartRed-14-7 , Click OK-tiny-13-17 in the Command-Manager.

One rotating-Part is kinematically-defined (it is a Rocker), the other rotating-Part is not kinematically-defined.

Use Add Pulley

GST-CM-AddPulley-A

STEP 1: Start the Add Pulley command

GST-Icon-AddPulley

1.Machine elements toolbar > Add Pulley

Add Pulley opens in the Command-Manager.

STEP 2: Select the elements

Do Add Pulley to the rotating-Part that is kinematically-defined (the Rocker)

1.Click the Pin-Joint

2.Click the Motion-Path FB

The Part-Editor opens with sketch-path to which you add the Motion-Path FB

3.Click the radius Dimension of the Arc

The Part-Editor closes

4.Click the Part joined with a Pin-Joint at the center of the Arc.

Click OK-tiny-13-17 in the Command-Manager.

We add for you a Pulley.
GST-Tut17-TwoBelts-G

Do Add Pulley again, to add a Pulley to the right-hand Arc and Part. This a Driven-Pulley.

Notes:

•The Driving-Pulley is the Rocker.

•Linear-Speed of Belt = Radius of Driving-Pulley × Angular-Velocity of Driving-Pulley(Rocker)

•Angular-Velocity of the Driven-Pulley = Linear-Speed of Belt ÷ Radius of Driven-Pulley

STEP 3: Edit the Pulleys

Double-click each Pulley to open the Pulley dialog

Enter:

Driving-Pulley : Number-of-Teeth = 50

Driven-Pulley : Number-of-Teeth = 72
GST-Tut17-TwoBelts-D

tog_minus        Step 2:  Add Second Belt

Add Motion-Path of Belt 2, and two Pulleys

GST-Tut17-TwoBelts-E

STEP 1: Add a closed sketch-path to represent the path of the Belt #2

1.Edit the Base-Part :

2.Add a sketch-path to represent the path of a BeltRed-14-1.

3.Click Geometry toolbar: Merge-Points: Merge the center-PointRed-14-2 of Arc #1 on Belt #2, with the center-Point of the Arc #2 on Belt #1

4.Click Add Dimension : Click each Arc Red-14-3. The radius of each Arc is not important.

5.Close the Part-Editor

GST-Tut17-TwoBelts-F

STEP 2: Add a Motion-Path FB

1.Kinematic FB toolbar > Add Motion-Path FBRed-14-4

Click one of the sketch-elements in the sketch-path that represents the Belt #1.

Click OK-tiny-13-17 in the Command-Manager

A Motion-Path FBRed-14-4 is in the graphic-area.

A Motion-PointRed-14-5 is at the start-Point of the sketch-element that you select.
GST-Tut17-TwoBelts-G

STEP 3: Add the Part for the Driven-Pulley of Belt #2

We need one more Part for the Driven-Pulley of Belt #2 . It is a Part that is free before we do Add-Pulley.

1.Add PartRed-14-6: Drag to add the Part. The length of the Part is not important.

2.Add Pin-JointRed-14-7: Click the start-Point of the Part and the center-Point of the other Arc.

Use Add Pulley

GST-Tut17-TwoBelts-H

STEP 1: Add the Driving-Pulley for Belt#2

GST-Icon-AddPulley

1.Machine elements toolbar > Add Pulley

Add Pulley opens in the Command-Manager.

You must select four elements - see images Red-14-8Red-14-4Red-14-3Red-14-9 above and left

1.Click Pin-JointRed-14-8

2.Click Motion-Path FBRed-14-4

The Part-Editor opens to show the sketch-path of the Belt in the Base-Part

3.Click the radius DimensionRed-14-3 of the Arc sketch-element, at the Pin-JointRed-14-8

The Part-Editor closes.

4.Click the PartRed-14-9 that has a Pin-JointRed-14-8 at the center-Point of the Arc

5.Click OK-tiny-11-15 to close the Command-Manager.

We add for you a Driving-Pulley
GST-Tut17-TwoBelts-J

STEP 2: Add the Driven-Pulley for Belt #2

GST-Icon-AddPulley

1.Machine elements toolbar > Add Pulley

Add Pulley opens in the Command-Manager.

You must select four elements - see images Red-14-7Red-14-4Red-14-3Red-14-6 above

1.Click Pin-JointRed-14-7

2.Click Motion-Path FBRed-14-4

The Part-Editor opens to show the sketch-path of the Belt in the Base-Part

3.Click the radius DimensionRed-14-3 of the Arc sketch-element at the Pin-JointRed-14-7

The Part-Editor closes.

4.Click the PartRed-14-6 that has a Pin-JointRed-14-7 at the center-Point of the Arc

5.Click OK-tiny-11-15 to close the Command-Manager.

We add for you a Driven-Pulley