Chapter 4 Hydraulic Actuators Structure features The vanes in a vane motor are positioned radially with a zero vane angle(0-0). A shuttle valve is set at the path between high/low pressure oil chambers and the vane bottomto ensure high pressure oil at the vane bottom.To ensure a normal startup,a spring with preload is mounted at the vane bottom to prevent the connection ofhigh and low pressure chambers when high pressure oil enters into the vane motor.Vane type motors are small in size and thus the moment of inertia, making a short reaction time and applicable to frequent direction-changing occasions. However vane type motors find more applications in small torque,high speed. low mechanical performance request occasions due to its large leakage and inadequate stabilization at low speed. 11 Homepage List Upwards Downwards Return Exit
Chapter 4 Hydraulic Actuators 11 Structure features The vanes in a vane motor are positioned radially with a zero vane angle (θ=0). A shuttle valve is set at the path between high/low pressure oil chambers and the vane bottom to ensure high pressure oil at the vane bottom. To ensure a normal startup, a spring with preload is mounted at the vane bottom to prevent the connection of high and low pressure chambers when high pressure oil enters into the vane motor. Vane type motors are small in size and thus the moment of inertia, making a short reaction time and applicable to frequent direction-changing occasions. However vane type motors find more applications in small torque, high speed, low mechanical performance request occasions due to its large leakage and inadequate stabilization at low speed
Chapter 4 Hydraulic Actuators 3.Gear motors Play DVD Fig.4-4 Operating principle of external gear motor 12 Homepage List Upwards Downward止 Retumn Exit
Chapter 4 Hydraulic Actuators 12 3. Gear motors Fig. 4-4 Operating principle of external gear motor
Chapter 4 Hydraulic Actuators 4.1.3 Low-speed motors Low-speed motors are usually radial piston motors.They possess high pressure and large delivery to meet the needs of low speed rotation and large torque.Because of their large size and large moment of inertia,they are not suitable for the applications which require rapid response and frequent direction changing Low-speed motors may be further classified based on how they function:(1)single-acting motors which provide a push in one direction;(2)double-acting motors which provide push in both directions;(3)multiple-acting motors which provide push in many directions. 13 Homepage List Upwards Downwards Retumn Exit
Chapter 4 Hydraulic Actuators 13 4.1.3 Low-speed motors Low-speed motors are usually radial piston motors. They possess high pressure and large delivery to meet the needs of low speed rotation and large torque. Because of their large size and large moment of inertia, they are not suitable for the applications which require rapid response and frequent direction changing. Low-speed motors may be further classified based on how they function: (1)single-acting motors which provide a push in one direction; (2)double-acting motors which provide push in both directions; (3)multiple-acting motors which provide push in many directions