Internal Geneva Mechanism

AIM: Run a motion analysis for internal Geneva mechanism.

OBJECTIVES:

• Create 3D models for driver and driven wheels.
• Perform motion analysis by rotating the driver wheel at 10 rpm.
• Perform motion analysis by rotating the driver wheel at 20 rpm.
• Perform motion analysis with using 60 fps and 120 for both rpm.
• Contact force (between driving and the driven wheel) as a function of time.
• Angular Displacement of the driven wheel.
• Compare the contact forces with and without "Precise contact"

INTERNAL GENEVA MECHANISM

The Geneva mechanism translates a continuous rotation into an intermittent rotary motion. The rotating drive wheel is usually equipped with a pin that reaches into a slot located in the driven wheel that advances it by one step at a time.There are mainly three types of geneva mechanism which is as follow:

1.External Geneva Mechanism

2.Internal Geneva Mechanism

3.Spherical Geneva Mechanism

STEP-WISE PROCEDURE:

• First, we have to create a driven and driver with the given dimension on challenges in front plane.

• Now we have to assemble driven and driver wheel with appropriate constrain in front plane.

• Then go to motion analysis and give the contact between driver wheel and driven wheel.
• Give the motor to driver wheel and set the speed 10 rpm.

• Set the frames per second to 60.
• Then calculate the motion data and plot the graph for the angular displacement of driver and driven wheel and contact force between driver and driven wheel.
• Now in another motion study check precision contact and plot all the graph.

• Then export the data of both studies to excel and make plot there.
• Then increase the frames per second to 120 for both study and plot the graph.
• Now for the input speed of 20 rpm repeat the above points.

OUTPUT PLOTS

Case 1: Perform motion analysis by rotating the driver wheel at 10 rpm with 60 fps

Angular velocity of driver wheel

Angular displacement of driver wheel

Angular displacement of driven wheel

Contact force between driver and driven wheel

Case 2: Perform motion analysis by rotating the driver wheel at 10 rpm with 120 fps

Angular velocity of driver wheel

Angular displacement of driver wheel

Angular displacement of driven wheel

Contact force between driver and driven wheel

Case 3: Perform motion analysis by rotating the driver wheel at 20 rpm with 60 fps

Angular velocity of driver wheel

Angular displacement of driver wheel

Angular displacement of driven wheel

Contact force between driver and driven wheel

Case 4: Perform motion analysis by rotating the driver wheel at 20 rpm with 120 fps

Angular velocity of driver wheel

Angular displacement of driver wheel

Angular displacement of driven wheel

Contact force between driver and driven wheel

CONCLUSION

1. When we increase the rpm than the contact force between the driver and driven wheel is increased.
2. Contact force between driver and driven wheel is reduced when we use precision contact option.
3. When we use higher frames per second, we get more accurate results.
4. We can see that there is some time lag between with precision contact and without precision contact which is increases with time duration in all the graph. So, we can say that for obtain particular position time required with precision contact is more compare to the without precision contact.

Google drive link for part and assembly

https://drive.google.com/drive/folders/1IrwBXmaE4Qyxff0plhb1Mp4Zzav4LgrP?usp=sharing