In the middle opening system, the main reversing valve of the middle opening system is in the middle position, through which the hydraulic pump is unloaded, and the liquid returns to the oil tank under low pressure. This kind of system generally uses constant displacement pump as oil source; When the reversing valve is in the middle position, the energy transmission starts with a low value that is basically zero, and the energy rises after changing, so that the pressure liquid enters customized Micro cycloid motor The actuator acts on the load; When the reversing valve is in the middle position, the internal leakage is very small. Generally, when the same function is achieved, the energy consumption of the intermediate open circuit is smaller. in Zhengzhou customized Open system is mostly used for working conditions requiring intermittent movement or supporting load, such as prime movers that do not want to start and stop frequently. The system has high efficiency, and needs to use makeup oil pump and flushing valve for oil makeup and heat exchange.
The radial piston hydraulic motor uses a cam ring with a special curve to make each plunger reciprocate several times within one cycle of cylinder block rotation, which is called multi action customized Micro cycloid motor Internal curve radial plunger hydraulic motor (referred to as internal curve motor) is used. The internal curve motor has the advantages of small size, light weight, radial force balance, small torque ripple, high starting efficiency, stable operation at very low speed, etc. It has been widely used Micro cycloid motor Manufacturer In marine machinery. Working principle of inner curve motor: the inner wall of the cam ring (housing) is composed of x evenly distributed curved surfaces with the same shape. Each curved surface with the same shape can be divided into two symmetrical sides. The side that allows the plunger set to extend outward is the working section (oil inlet section), and the opposite side is called the oil return section. The number of reciprocating times of each plunger per revolution of the hydraulic motor is equal to the number of curved surfaces of the cam ring x (x is called the number of times of action of the motor).
At present, the system used in series by multiple cycloidal motors (see Figure 1) is applied to sweepers, trenchless drills and airport luggage carts. The output shaft of the hydraulic motor often leaks oil during use, so it is useless to replace the dynamic seal of the output shaft. In series application, the problem of casing oil leakage pressure is ignored. The oil leakage pressure of the housing refers to the maximum pressure that the motor shaft seal can bear after the hydraulic motor is fully lubricated inside; If the hydraulic motor is applied customized Micro cycloid motor Improper. After the machine has been working continuously for a period of time, due to various factors, the oil in the housing will not be released, resulting in higher and higher pressure in the housing of the hydraulic motor, which first leads to the failure of the shaft seal. The casing leakage pressure mentioned here is not the bursting pressure of the casing, but the pressure that the motor output shaft dynamic seal can bear. In the motor samples of some manufacturers, only the back pressure is mentioned. Actually, back pressure refers to electricity Micro cycloid motor Manufacturer The return oil pressure of the engine, not the oil discharge pressure of the casing. During operation, the requirements for the oil discharge pressure of the cycloidal motor housing are as follows. Eaton is the world's first cycloid motor manufacturer. In China's domestic cycloidal motor manufacturing industry, Jining Jinjia Hydraulic Co., Ltd. uses Eaton technology to produce cycloidal motors. Its output shaft dynamic seal has better bearing capacity, that is, the unique internal oil circuit design of the company's products enables internal oil drainage not only to lubricate parts, but also to discharge excess oil while maintaining a certain housing oil drainage pressure.
The manufacturer of the hydraulic motor has explained to us the relevant knowledge about the speed and low-speed stability of the hydraulic motor. The speed of the hydraulic motor depends on the flow of the supply fluid q and the discharge of the hydraulic motor itself v. The hydraulic motor has internal leakage. Not all the liquid entering the motor drives the hydraulic motor to work. Some of the liquid is lost due to leakage, and the actual speed of the motor is lower than the ideal situation. When the working speed of the hydraulic motor is too low, it cannot maintain a uniform speed, and it stops when entering Zhengzhou Micro cycloid motor The unstable state is a creeping phenomenon. The high-speed hydraulic motor is required to work at a speed below 10r/min and the low-speed high torque hydraulic motor is required to work at a speed below 3r/min. All hydraulic motors can meet the requirements. Generally speaking, the low-speed stability of low-speed large torque hydraulic motors is better than that of high-speed motors. Due to the large emissions and size of the low-speed high torque motor, the sliding speed of the friction pair will not be too low even if the rotation speed is low customized Micro cycloid motor Large emissions, relatively small impact of leakage, large rotation inertia of the motor itself, easy to obtain good low-speed stability.
After disassembling and inspecting the hydraulic motor installed on the drill, it was found that the friction surface of the valve disc and the port plate of the hydraulic motor was severely worn, and the deepest worn part was 0. 15mm; The output shaft oil seal is leaking. Cause analysis of oil leakage of output shaft oil seal. After disassembly inspection and test, the axial and radial clearances of the output shaft meet the standard requirements customized Micro cycloid motor There is no obvious wear on the oil seal mating surface. However, it is found that the oil seal rubber has hardened and its elasticity has deteriorated. With the increase of sealing lip wear, the pre tightening capacity and sealing performance decrease, and the excessive oil temperature accelerates the wear of sealing lip; In addition, due to the liquid Zhengzhou Micro cycloid motor The leakage of the pressure motor causes the back pressure in the housing to be too high, which further aggravates the wear and leakage of the sealing lip. The smaller the friction of the rotor in the stator sleeve, the higher the mechanical efficiency of the motor.
