Internal Geneva Mechanism

Aim:

• Create 3D models for driver and driven wheels for internal geneva mechanism and Do motion analysis.
• Perform motion analysis by rotating the driver wheel at 10rpm.
• Obtain the following plots
• 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"
• Show image for precise contact selection
• Use 60 Frames per second for 10 rpm and then 120 Frames per second for 20 Rpm
• Once you have completed the previous study, change the rpm to 20
• Make a plot of the driver wheel's angular velocity and discuss the results

Introduction :

Geneva mechanism, also called Geneva Stop, one of the most commonly used devices for producing intermitten rotary motion, characterized by alternate periods of motion and rest with no reversal in direction. It is also used for indexing (i.e., rotating a shaft through a prescribed angle).

Basic theory on the motion study:

motion study as the “Science of eliminating wastefulness resulting from ill-directed and inefficient motions”. The main aim of motion study is to find the scheme of least wastage of labour. Subsequently, the scope of Motion Study was enlarged and it was named as Method Study.

entire motion study setup :

Model Description-

Driver :

Driven :

Assembly:

Switching to SolidWorks Motion Manager Switch to SolidWorks Motion by clicking the motion analysis tab in the bottom left hand corner.

SolidWorks Assembly Mates.

Specifying the Input Motion and

Under Motor Type selet Rotary Motor.

Select contact between parts.

Go to settings and set frames per seconds as per our requirements.

Select Simulation time.

Running the Simulation.

Looking at the Results. And select plots as per our requirements.

how to use precise contact :

Results and explanation:

1).driver wheel speed 10 RPM ( 60FPS):

Without precise contact :

With precise contact :

Angular Displacement:

2).driver wheel speed 20 RPM (120FPS):

Without precise contact :

With precise contact :

Angular Displacement :

Results Explanation :

If the RPM say 10 RPM to 20 RPM of the driver wheel increases then the angular displacement of the driven wheel increases according to the time.

By, comparing the contact force between precise contact and without precise contact it shows that,

if the precise contact is considered then the value of contact force will increases and give more accurate results

By, showing the angular velocity graph some jerk will observe at the begning of the motion of the driven wheel or intial contact between driver and driven wheel.

By, the angular displacement graph of the driven wheel it observe that, for a few second driven wheel will at the rest position and again revolve upto 90 degree and this process will continued.

youtube video link :https://youtu.be/smnxxWM2hSA