附件24.3 Problem7-5 7-For a special milling machine hydraulic system,the output flow rate of the pump is 30L/min.The setting pressure of the relief valve is 2.4MPa,and the operation areas of the two chambers in the cylinder are 50cm2and 25cm2respectively.The cutting load is 9000N and the friction load is 1000N.The flow rate through the adiusting valve when cutting is 1.21/min.If the leakage of the components and the pressure loss are neglected,then 1)What is the feed speed of the piston and the circuit the piston is closing to the work piece at a high speed? 2)What are the working feed speed v2and the circuit efficiency n during cutting at feed speed? X Problem 7-6 7-7Ina variable displacemen pump-fixed speed and the delive of the variable disolacement mototoingthPand the oie e the d ivery mechanical efficiencies of the pump and motor are all 95.ie====0.95 (1)What is the delivery of the pump when the rotating speed of the motor is 1000r/min? (2)What is the rotating speed of the motor when the od orque of the motor ism? (3)What is the largest ouput power of the pump? 7-8 Draw the operating principle chart of a displacement speed regulation circuit composed by a throttle valve mounted in the oil return path and a pressure differential type variable displacement pump.附件 24.3 Problem 7-5 7-6 For a special milling machine hydraulic system, the output flow rate of the pump is 30L/min. The setting pressure of the relief valve is 2.4MPa, and the operation areas of the two chambers in the cylinder are 50cm2 and 25cm2 respectively. The cutting load is 9000N and the friction load is 1000N. The flow rate through the adjusting valve when cutting is 1.2L/min. If the leakage of the components and the pressure loss are neglected, then: 1) What is the feed speed v1 of the piston and the circuit efficiency η1 when the piston is closing to the work piece at a high speed? 2) What are the working feed speed v2 and the circuit efficiency η2 during cutting at feed speed? Problem 7-6 7-7 In a variable displacement pump-fixed displacement motor circuit, the rotating speed and the delivery of the variable displacement pump are 1500r/min and 8mL/r respectively, while the delivery of the fixed displacement motor is 10mL/r, the setting pressure of the safety valve is 40×105 Pa, and the volumetric and mechanical efficiencies of the pump and motor are all 0.95, i.e., MV Mm 0.95 ηpV =ηpm =η =η = . (1) What is the delivery of the pump when the rotating speed of the motor is 1000r/min? (2) What is the rotating speed of the motor when the load torque of the motor is 8N·m? (3) What is the largest output power of the pump? 7-8 Draw the operating principle chart of a displacement speed regulation circuit composed by a throttle valve mounted in the oil return path and a pressure differential type variable displacement pump