Internal Geneva Mechanism

SIMULATION OF INTERNAL GENEVA MECHANISM

AIM:

• To create the 3D model of the driver and driven wheel of the mechanism using the given 2d drawing
• To find out the contact forces between driver and driven wheel, the angular displacement of the driven wheel by conducting motion analysis (@10rpm and 20 rpm)
• In motion analysis, compare the result of obtained contact forces with 'precise contact' and without precise contact option.

THEORY:

• Geneva mechanism is used to convert continuous rotation motion into intermittent rotary motion.
• It consists of driver wheel with pin and driven wheel with slots
• Internal Geneva mechanism one of the variant of Geneva mechanism, in this angle by which driver has to rotate to cause one step rotation of the driven wheel is always less than 180degree

SIMULATION

• The given 2D drawing is used to create a 3D model of driver and driven wheel in part modeling of solid works
• The first, sketch is done using tools like a circle, offset, circular pattern and at the same time sketch is constrained using dimensioning and adding relations.
• Then it is extruded to a specified dimension to create a 3D model of the part
• Assembly is done, by keeping them motion analysis in mind, according to that necessary mates are provided

• In motion analysis, the rotor is given to divert wheel axis and solid contact is established between driver and driven wheel (by giving dry steel as material to both)
• In settings of motion analysis 60fps for 10rpm motion analysis and 120fps for 20rpm is given to get the result at each and every point of the seconds

• contact forces and angular displacement were defined in the result section

RESULT

• contact forces are obtained with precise contact option and without precise contact option and it is compared by plotting the graphs
• With a precise contact option, we get large fluctuating force values during contact, while without a precise contact option we get two peak values at the time of contact and disconnection

• Angular displacement of the driven wheel is obtained

For 10rpm

• For every single rotation of driver wheel (6sec), the driven wheel is displaced by 90 degrees, therefore for every 4 rotation of the driver wheel, driven wheel complete single rotation (24 sec)

For 20 rpm

• For every singel rotaion of driver wheel (3 sec), driven wheel is displaced by 90 degree, therefore for every 4 rotation of the driver wheel, driven wheel complete single rotation (12 sec)

• Angular velocity of the driver wheel remains constant thoroughly

ANIMATION

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