超星 - Chapter_3_Pumps - 查题吧

单选题

What is the maximum angle between the cylinder block and shaft axis of a bent-axis piston pump?

A. 30°
B. 50°
C. 45°
D. all the above

单选题

Which of the following statements are true?① piston pumps are self-priming.② piston pumps require high maintenance.③ piston pumps have low cost of production.④ piston pumps have low volumetric efficiency.

A. ① and ②
B. ③ and ④
C. ① and ③
D. all the above

单选题

The most common methods to solve the problem of oil trapped or surrounded oil in gear pump are as follows: ().

A. reduces the speed
B. designs with unloading groove
C. increases the oil suction port
D. reduces the gas temperature

单选题

For a gear pump, if the output pressure is less than the rated pressure and is not zero, and the speed remains unchanged, the relationships of a. actual flow, b. theoretical flow and c. rated flow should be ().

A. b>a>c
B. a>b>c
C. c>a>b

单选题

In order to make the gear of gear pump mesh smoothly, seal the suction oil chamber strictly and supply oil evenly and continuously, the overlap coefficient r of gear meshing must be made () 1.

A. greater than
B. equal to
C. less than

单选题

There are three leakage ways in CB-B gear pump and _________ has the greatest impact on volumetric efficiency. ()

A. gear end clearance
B. gear tip clearance
C. gear base clearance
D. A + B + C

单选题

The features of external gear pump include ().

A. the structure is compact and the flow rate is easy to adjust
B. the method of reducing the oil inlet is usually used to reduce the radial imbalance force
C. the noise is small, the oil delivery is uniform, the volume is small and the weight is light
D. low cost, reliable work, weak self-priming ability, mostly used in low-pressure system

单选题

Which type of displacement is observed in gear pumps?

A. only variable displacement
B. only fixed displacement
C. both fixed and variable displacement
D. none of the above

单选题

What causes suction of fluid into the gear pump?

A. pressure drops during disengagement of teeth at the suction side
B. pressure increases during disengagement of teeth at the suction side
C. pressure drops during engagement of teeth at the suction side
D. pressure increases during engagement of teeth at the suction side

单选题

What is the principle of operation used in gear pumps?

A. two gears rotate in same direction
B. two gears rotate in opposite direction
C. two gears rotate in same and opposite direction
D. none of the above

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