List of top Design of Machine Elements Questions

A custom pinion, with a width equal to 10 times the module, has 20 full depth teeth and a pressure angle of 20 degrees is being designed. It should transmit a torque of 95 N-m to a corresponding spur gear.

Considering the safe bending stress to be 180 MPa and form factor to be 0.342, the module of the pinion is ______ mm (rounded off to one decimal place).

Note: The Lewis equation gives the tangential force as \( F_t = \sigma b Y m \), where \( \sigma \) is the safe bending stress, \( b \) is the width, \( Y \) is the form factor, and \( m \) is the module.

An engineering student is fabricating a setup and needs a key for connecting a shaft to the hub of a rotating machine element. The student uses a sunk key which is tapered and prevents relative axial motion.
Which ONE of the following keys did the student most likely use?
Given below are two statements: One is labelled as Assertion A and the other is labelled as Reason R.
Assertion (A): The torque transmitting capacity of a cone clutch is 4.62 times that single plate clutch for given dimensions.
Reasons (R): When the semi-cane angle of a cone clutch decreases, it results in mass wedging action and the force required to disengage increases.
In the light of the above statements, choose the correct answer from the options given below:
A ball bearing operating at a load F has 10,000 hours of life. When the load is doubled, the life of the bearing, (in hours) is:
The maximum efficiency in a Screw Jack is given as: