Page 188 - Analysis and Design of Machine Elements

Analysis and Design of Machine Elements
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3 What factors affect the uniformity of chain speed transmission?
4 What lubrication methods are available for chain drives? How does one select a suit-
able method?
5 How could one improve operating conditions if wear occurs on a roller chain?

Objective Questions

1 A power transmission includes a belt drive, a chain drive and a gear drive. Which of
the following is the best arrangement between a motor and a working machine?
(a) belt drive gear drive chain drive
(b) chain drive gear drive belt drive
(c) belt drive chain drive gear drive
(d) chain drive belt drive gear drive

2 In a chain drive, reducing the number of teeth of driving sprocket will
cause________.
(a) the severity of speed unevenness of chain drive
(b) the chain to jump off the sprocket more easily after wear
(c) poor lubrication that may lead to gluing
(d) the increase of rotational speed of driving sprocket

3 At a constant rotational speed, if we want to reduce speed unevenness and dynamics
load of a chain drive, we can ___________.
(a) increase p and z 1
(b) increase p and reduce z 1
(c) reduce p and increase z
1
(d) reduce p and z
1
(where z is the number of teeth of driving sprocket, p is pitch)
1
4 The number of rows of a multiple-strand chain is generally no more than four to ___.
(a) facilitate installation
(b) limit axial width of chain drive
(c) ensure even loading on each row
(d) reduce the weight of chain

5 The purpose of limiting the maximum number of sprocket teeth is _________.
(a) to ensure the strength of chain
(b) to ensure the transmission stability of chain drive
(c) to ensure the speed ratio selection of chain drive
(d) to prevent the chain from jumping off the sprocket