The volumetric speed control circuit with constant power output is ( ).
A. variable displacementpump--variable displacement motor circuit
B. fixed displacement pump--variable displacement motorcircuit
C. variable displacement pump--fixed displacement motorcircuit
D. fixed displacement pump--fixed displacement motorcircuit
查看答案
The function of the relief valve is to cooperate with the oil pump to overflow the surplus oil in the system, so as to keep the system__________ stable.()
A. pressure
B. flow rate
C. flow direction
D. cleanliness
Pressure control circuit includes ().
A. locking circuit
B. pressure regulating, pressure reducing and unloading circuit
C. pressure regulating and directional control circuit
D. throttling and volume speed regulating circuit
Why is pilot operated check valve used in clamping operation?
A. to reduce leakage in spool valve
B. to avoid decrease in pressure during clamping
C. both a and b
D. none of the above
Which of the following statements is true, for two pumps used in circuit when initially fast operation is performed to reach a workpiece and feeding operation is done at a slow speed?
A. initially to reach a workpiece, a tool must be connected to a pump of high discharge and low pressure
B. initially to reach a workpiece, a tool must be connected to a pump of low discharge and high pressure
C. for feeding operation low discharge low pressure pump is required
D. none of the above
微信支付 
支付宝支付