Internal Geneva Mechanism

Objective:

1) prepare 3-D model driver and driven part of internal Geneva mechanism.

2) create the assembly of a Geneva mechanism.

3) simulation of the Geneva mechanism at 10 and 20 RPM

4) compare the graph for the precise contact and non-precise contact force.

5) compare the graph of the angular velocity of the driver and driven at 10 and 20 RPM

6) get the graph of angular displacement.

Introduction:

Geneva mechanism is used for the transfer continuous rotary motion into the intermediate rotary motion. This use in most of the automation work or feeding mechanism. There are mainly three types of Geneva mechanism internal, external, spherical. Here I perform the simulation on the Internal Geneva mechanism.

In the Geneva mechanism Driver Rotate the Driven Part. The driver is rotating at the constant speed and when its pass from the slot of the driven member its rotate the Driven member.

During this contact, some force is developed between Pin and Contact surface of the driven member. We have to analyze that force. for the precise and non-precise contact also we have to compare the effect of the RPM on contact force, angular displacement, and angular velocity.

Dimensions:

Model and Assembly:

Driven:

Driver:

Assembly:

Material:

here When I define the contact, I choose the material as dry steel.

Results:

For 10 RPM all the result given below.

1) contact force without precise contact,

2) contact force with precise contact and 60 Frame,

3) angular displacement of driven without precise contact,

4) angular displacement of driven with precise contact and 60 frames,

5) angular displacement of the driver without precise contact,

6) angular velocity of the driver without precise contact,

7) angular velocity of the driver with precise contact,

8) angular velocity of the driven member without precise contact,

9) angular velocity of the driven member with precise contact,

For the 20 RPM, all the result given below and 120 frames,

10) contact force with precise contact,

11) angular displacement of the driven member with precise contact,

12) angular displacement for driver member with precise contact,

13) angular velocity of the Driver with precise contact,

14) angular velocity of the Driven with precise contact,

Result:

Here I take the solution without precise contact and with precise contact for 10 RPM and60 frame in the precise contact. Where in the precise contact I got the less fluctuation and points were near to each other and accuracy of the result is higher. we also have the solution for 20 RPM precise contact I compare both of them over here.

first, if talk about the contact force graph where we got a peak in the graph at a different point because when the pin of driver moves inside the driven member slot there some clash occurs in between the driver and driven.

comparatively, we have a higher reaction force in the 20 RPM rotation speed. But in the same force decreases simultaneously. Whereas in the 10 RPM rotation speed from the starting to end our force is increasing.

Second, I determine the angular displacement of the driver and the driven member in the graph of 10 RPM and at 20 RPM, we can see a clear difference that at the higher RPM we get the higher angular displacement. In the precise contact graph, we got a smoother graph than the non-precise contact. In the 20 RPM graph, we have lines nearer to each other than the 10 RPM graph.

Third, I determine the angular velocity for the driver member its constant for the constant RPM but when we show in Excel graph we show the variation at some point. For 10 RPM angular velocity is 60 Deg/sec and for 20 RPM angular velocity is 120 Deg/sec.

Forth, I determine the angular velocity of the driven member its fluctuate from 0 to 25 for the 10 RPM graph, and from 0 to 50 for the 20 RPM graph. here also it is observed that the graph are smoother for the precise contact type solution.

Here also we got the peck point in the angular displacement graph of the driven member because when pin of the driver sudden come into the contact with driven its experience some jerk motion that is the reason that we got the peak in the graph.

Go through zip file its contain all the 3D model, animation video, graph.