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 Crane 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 Crane 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.
When the high-pressure oil enters the oil distribution shaft and enters each plunger cylinder hole of the working section through the oil distribution window, the corresponding plunger set is pushed against the curved surface of the cam ring L (housing), city in Guangxi Crane cycloid motor The cam ring surface gives a reaction force to the plunger at the contact position. This reaction force N acts on the common plane where the cam ring surface contacts the roller. This normal reaction force N can be decomposed into radial force PH and circumferential force T, which are balanced with the hydraulic pressure at the bottom of the plunger, while the circumferential force T overcomes the load torque, customized Crane cycloid motor Drive cylinder 2 to rotate. Under this working condition, the cam ring and oil distribution shaft do not rotate. At this time, the plunger corresponding to the oil return section of the cam gear moves in the opposite direction, and the oil is discharged through the oil distribution shaft.
Hydraulic transmission system, the hydraulic transmission system is generally an open loop system without feedback, which mainly transmits power, supplemented by information, and pursues the perfection of transmission characteristics. Hydraulic elements customized Crane cycloid motor The characteristics of components and their interactions determine the working characteristics of the system, and its working quality is greatly affected by the changes of working conditions. Hydraulic drive system is widely used. The hydraulic system of most industrial equipment belongs to this category. In the hydraulic control system, servo valves and other electrohydraulic devices are mostly used in the hydraulic control system Crane cycloid motor Manufacturer The control valve constitutes a closed-loop system with feedback, which mainly transmits information, supplemented by power, and pursues the perfection of control performance. The system adds detection feedback, which can combine common components into an accurate control system, and its control quality is less affected by the change of working conditions. Hydraulic control system is widely used in high-precision CNC machine tools, metallurgy, aerospace and other industries.
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 city in Guangxi Crane 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 Crane cycloid motor Large emissions, relatively small impact of leakage, large rotation inertia of the motor itself, easy to obtain good low-speed stability.
The output pressure of the hydraulic motor also depends on the load. Rated pressure Pn: the rated pressure refers to the working pressure that the hydraulic motor can withstand during continuous operation. It can customized Crane cycloid motor To ensure the volumetric efficiency and service life of the hydraulic motor. Working pressure P: the working pressure is the actual pressure of oil input when the hydraulic motor is working Crane cycloid motor Manufacturer power. Its value depends on the size of the load. However, the maximum working pressure is determined by the safety valve in the hydraulic system. The throttle adjustment value must not exceed the maximum pressure value of the hydraulic motor. The third is the maximum pressure: the limit pressure that the motor is allowed to overload in a short time. Pn ≤ Pmax value.
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 Crane 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 city in Guangxi Crane 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.
