ANALYSING THE INTERNAL GENEVA MECHANISM USING SOLIDWORKS MBD

AIM: TO ANALYSE THE MULTI BODY DYNAMICS FOR INTERNAL GENEVA MECHANISM USING SOLIDWORKS.

OBJECTIVE:

• To create 3D models for driver and driven wheels.
• To perform motion analysis by rotating the driver wheel at 10 rpm.
• To obtain a plot for contact force between driving and driven wheel.
• To obtain a plot for Angular displacement of the driven wheel.
• To compare the contact forces with and without “Precise contact”.
• To obtain a plot for Angular velocity of the driving wheel.
• To create motion study for two conditions-

1. 60 frames per second and 10 rpm motor speed.
2. 120 frames per second and 20 rpm motor speed.

• To export the results to a spreadsheet.

OVERVIEW:

The Geneva drive is a gear mechanism that translates a continuous rotation into an intermittent rotary motion. The rotating drive wheel has a pin that reaches into a slot of the driven wheel advancing it by one step. The drive wheel also has a raised circular blocking disc that locks the driven wheel in position between steps.

External Geneva mechanism-

In this type of mechanism, the Geneva cross is connected with cam drive externally which is the most popular and can withstand higher mechanical stresses.

Internal Geneva mechanism-

In this type of mechanism, the Geneva cross and cam drive are connected internally in the closed box. The driver and driven wheel rotate in same direction.

Application and Uses-

• It is applicable in the production industries and in automobile industries for mass production.
• Modern film projectors may also use an electronically controlled indexing mechanism, which allows for fast-forwarding the film.
• Geneva wheels having the form of the driven wheel were also used in mechanical watches, but not in a drive, rather to limit the tension of the spring such that it would operate only in the range where its elastic force is nearly linear.
• Indexing tables in assembly lines, tool changers for CNC machines, and so on.

3D MODELS AND DIMENSIONING:

1. Driven wheel

2. Driving wheel

3. Assembly

BODY OF CONTENT:

1. Study-1 (with 60 frames per second and 10 rpm motor speed)

Firstly we will set up the motor speed to 10 rpm and the contacts between the parts.

Now, setting up the number of frames equal to 60 frames per second as -

Now we will calculate the study and we will get the different plots as by clicking on result and plots section as -

To compare the contact force with “Precise contact”

Click on the ‘precise contact’ as shown and then calculate the study and we will get the result for the same as -

2. Study-2 (with 120 frames per second and 20 rpm motor speed)

Firstly we will set up the motor speed to 20 rpm and the contacts between the parts.

Now, setting up the number of frames equal to 120 frames per second as -

Now we will calculate the study and we will get the different plots as by clicking on result and plots section as -

To compare the contact force with “Precise contact”

Click on the ‘precise contact’ as shown and then calculate the study and we will get the result for the same as -

RESULTS:

1. Study-1 (with 60 frames per second and 10 rpm motor speed)

>>Contact force between driving and driven wheel

>>Contact force between driving and driven wheel with “Precise Contact”

>>Angular displacement of driven wheel

>>Angular velocity of driving wheel

2. Study-2 (with 120 frames per second and 20 rpm motor speed)

>>Contact force between driving and driven wheel

>>Contact force between driving and driven wheel with “Precise Contact”

>>Angular displacement of driven wheel

>>Angular velocity of driving wheel

Link for Spreedsheet results, parts, plots -

https://drive.google.com/file/d/1KCTFsUIv_61avbsDIdzDX006P3-q-UUu/view?usp=sharing

ANIMATION VIDEO: