軸向柱塞馬達的工作原理

创建于02.24

Working principle of axial piston motor

(1) Type axial piston motor and axial piston pump are opposite in principle, so the structure of axial piston motor is basically the same as that of axial piston pump. However, in order to meet the requirements of forward and reverse rotation of the hydraulic motor, the structure of the valve plate and the size and shape of the oil inlet and outlet channels are generally completely symmetrical. At present, there are two basic types of axial distribution mechanism (axial distribution valve) and swash plate piston motor.

(2) The main advantages of axial piston motor are compact structure, high power density, high working pressure, easy to realize variable, rich variable mode and high efficiency. The disadvantages are complex structure, high price, poor anti pollution ability and high maintenance requirements.

working principle

Take the straight axis (swash plate) axial piston motor shown in Figure r as an example to illustrate the working principle of the axial piston motor. When the pressure oil enters into the oil inlet chamber of the motor, the slipper will be pressed against the swashplate by the force. The axial component FX (parallel to the axis of the plunger) of the reaction force n is balanced with the hydraulic pressure on the plunger. The vertical component FY of the reaction force n (perpendicular to the axis of the plunger) generates torque on the cylinder and motor axis, driving the hydraulic motor to rotate and deliver oil It can generate mechanical energy. The speed and rotation direction of the motor can be changed by changing the size and direction of the swash plate angle. Most axial piston motors with straight shaft (swash plate) end face distribution and axial piston pumps with the same structure can be used against each other.

The variable of axial piston high-speed hydraulic motor is similar to that of axial piston pump, which is realized by changing the angle of swash plate or swash shaft. The method of electro-hydraulic control is often used. The speed sensor or pressure sensor feeds back the changing speed or pressure to the electro-hydraulic proportional valve or servo valve with electricity to control the movement of the variable piston of the motor and realize the constant speed or pressure control of the hydraulic motor. This kind of control is easy to carry out the dynamic correction of the regulation process, and the best control can be achieved with the help of microcomputer. In order to make full use of the power of prime mover in the variable process of high-speed small torque and low-speed large torque, constant power variable motor can be used. In the constant current source system (that is, the flow of the pump source is basically constant), as long as the pressure difference between the inlet and outlet of the motor remains unchanged, the constant power control of the motor can be achieved approximately. Figure s shows the principle of constant power variable of axial piston motor. The variable piston of bidirectional variable displacement motor 2 is controlled by constant pressure control valve 5. If the load torque of the motor increases for some reason, in the constant current source system, when the motor displacement has not changed, its inlet pressure will increase. This pressure acts on the end of the spool of the constant pressure control valve 5, overcomes the spring force to move the spool to the left, and the piston of the variable cylinder l moves to the left, which increases the displacement of the motor, so the inlet pressure of the motor decreases. At the end of the adjustment process of the variable control system, when the variable piston stops, the valve core of the constant pressure control valve must be in the middle position, that is, the hydraulic pressure at the right end of the valve core is balanced with the spring preload at the left end. This means that regardless of the system load, the inlet pressure of the variable displacement motor remains constant throughout the adjustable range of the variable displacement motor. Since the oil source is a constant flow system, the constant power control of the motor is maintained by keeping the inlet pressure of the motor unchanged. When the load of the motor increases, the motor runs at a relatively large displacement, the speed decreases and the output torque increases, and the power basically remains constant. The control of the motor is a closed loop control system. In order to make the system stable and get higher response speed, it is necessary to set the gain and damping of the system properly. Throttle valve 4 is used to adjust the damping of the system, so that the system can get the fastest response speed under the premise of stability.

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