Page 405 - Analysis and Design of Machine Elements

Couplings and Clutches
3 List measures that could increase the load carrying capacity of a friction clutch. 383
4 What kinds of couplings have damping capability? Why is damping capability impor-
tant for a coupling?

Objective Questions

1 The main difference between a coupling and a clutch is _______.
(a) capability of overload protection
(b) capability for engagement and disengagement of two shafts at any time
(c) capability of misalignment compensation

2 The main function of a coupling and a clutch is to _______.
(a) cushion shock and reduce vibration
(b) transmit motion and torque
(c) prevent overload
(d) compensate for misalignment and thermal expansion

3 The resilient material in flexible couplings can _______.
(a) accommodate misalignment
(b) reduce friction
(c) cushion shock and reduce vibration
(d) increase load carrying capability

4 When a stiff shaft rotates at high speed and is subject to impact and vibration, a
_______should be selected.
(a) flanged coupling
(b) universal coupling
(c) Oldham coupling
(d) pin and bushing coupling

∘
5 When the angular misalignment is 30 , a _______ is the best choice.
(a) universal coupling
(b) flanged coupling
(c) gear coupling
(d) pin and bushing coupling

Calculation questions

1 A safety clutch with shear pins in Figure P13.1 transmits a torque of T = 500 N⋅m.
The clutch has two identical pins on the circle of diameter of D = 100 mm. Pins
m
are made of medium carbon steel and normalized, with an allowable stress of
[ ] = 400 MPa. It is required the safety clutch function at 50% of overload. Decide
the diameter of the pins.