Page 383 - Analysis and Design of Machine Elements

Sliding Bearings
3 What should one pay attention to while designing grooves on a bushing? 361
4 In the hydrodynamic sliding bearing design process, if the calculated minimum oil
film thickness h is too small or the temperature rise Δt is too high, what measures
min
could be taken to increase h or to reduce Δt?
min
5 What are the specific requirements for the liner materials of sliding bearings?

Objective Questions

1 A journal operates in a steady hydrodynamic lubrication state in a sliding bearing.
Which part of Figure P12.1 shows the right position of the journal?

F F F F

ω ω ω
O O O O
Oʹ Oʹ Oʹ ω Oʹ

(a) (b) (c) (d)
Figure P12.1 Illustration for Objective question 1.

2 To form hydrodynamic oil film, the inlet and outlet velocity profiles in a wedged
lubricated gap should be ___________.

(a) (b) (c) (d)
Figure P12.2 Illustration for Objective question 2.

3 At _______, the viscosity of lubricant in a sliding bearing should not be chosen as
high.
(a) overload
(b) high operating temperature
(c) high speed
(d) variable loads
4 While designing hydrodynamically lubricated bearings, we usually ________ to
reduce the working temperature of sliding bearings.
(a) increase the relative clearance and reduce the ratio of B/d
(b) increase the relative clearance and increase the ratio of B/d
(c) reduce the relative clearance and reduce the ratio of B/d
(d) reduce the relative clearance and increase the ratio of B/d