附件24.3 problem 2-11 problem 2-12 Chapter 3 3A fixed delivery 13.25L/min.The bala nce of the flow goes through a relief valve set at1.0x kPa to a reservoir at the atmospheric pressure.How much power is wasted? 3-2 In order to keep the vane in continuous contact with the cam ring in double-acting pumps,the vane slot tips usually connect with high pressure oil.This action,however,may bring about three aspects of side effects,what are they? 3-3 When selecting electric machine for pressure-limiting variable vane pumps,what kind of working conditions should we baseon for calculation 3-4 A gear pump is 48mm in the top circle diameter,24mm in gear width,and has a gear number of 14.If the highest working pressure is 10MPa,and the motor speed is 980r/min,what is the power of the motor? (volumetric efficiency of the pump=.90.the total efficiency=0.8) 3-5 An equal clearance 0.04mm exists between the two side surfaces and the gears (s=2=0.04(mm))in a gear pump.The rotating speed is 1000r/min,the output flow rate is 20L/min under a working pressure of 2.5MPa and the volumetric efficiency is 0.90.After working for a certain period. s expands to 0.042mm and s2 to 0.048mm due to friction (the other clearances were assumed to be not chans the3,=32=0.04mm) ucer requires the hydraulic motor to put out a torque of 52.5Nmd 30r/min.The hydraulic motor delivery is 12.5cmand both the volumetric and mechanical efficiencies of the hydraulic motor are09.What is the flow rate and the pressure needed? 4-2 A hydraulic motor has a delivery of 70mL/r providing an oil pressure of 10MPa and an input flow rate of 100L/min.If its volumetric and mechanical efficiencies are 09 and 0.94 respectively.and the (1)The output torque of the hydraulic motor; 附件 24.3 problem 2-11 problem 2-12 Chapter 3 3-1 A fixed delivery pump operating at 1750 r/m delivers 9.8mL/r. The load requires an average of 13.25L/min. The balance of the flow goes through a relief valve set at 1.03×104 kPa to a reservoir at the atmospheric pressure. How much power is wasted? 3-2 In order to keep the vane in continuous contact with the cam ring in double-acting pumps, the vane slot tips usually connect with high pressure oil. This action, however, may bring about three aspects of side effects, what are they? 3-3 When selecting electric machine for pressure-limiting variable vane pumps, what kind of working conditions should we base on for calculation? 3-4 A gear pump is 48mm in the top circle diameter, 24mm in gear width, and has a gear number of 14. If the highest working pressure is 10MPa, and the motor speed is 980r/min, what is the power of the motor? (volumetric efficiency of the pump = 90.0 η pv , the total efficiency = 8.0 η p ) 3-5 An equal clearance 0.04mm exists between the two side surfaces and the gears ( ) in a gear pump. The rotating speed is 1000r/min, the output flow rate is 20L/min under a working pressure of 2.5MPa and the volumetric efficiency is 0.90. After working for a certain period, s )(04.0 ss 21 == mm 1 expands to 0.042mm and s2 to 0.048mm due to friction (the other clearances were assumed to be not changed). If the working pressure and the rotating speed of the pump are constant, what is the volumetric efficiency? (Reminder: the surface clearance leakage takes up 85% of the total leakage when is the )(04.0 ) ss 21 == mm Chapter 4 4-1 A speed reducer requires the hydraulic motor to put out a torque of 52.5N.m and a rotating speed of 30r/min. The hydraulic motor delivery is 12.5cm3 /r, and both the volumetric and mechanical efficiencies of the hydraulic motor are 0.9. What is the flow rate and the pressure needed? 4-2 A hydraulic motor has a delivery of 70mL/r, providing an oil pressure of 10MPa and an input flow rate of 100L/min.If its volumetric and mechanical efficiencies are 0.92 and 0.94 respectively, and the backpressure is 0.2MPa in the return oil chamber of the hydraulic motor, calculate: (1) The output torque of the hydraulic motor;