Along the revolution direction of the rotor, the volume of the tooth cavity at the front side of the connection between the rotor and the stator becomes smaller, which is an oil discharge cavity, and the volume at the rear side becomes larger. When the connecting line passes through the two tooth roots of the rotor, the oil inlet ends and the largest tooth cavity appears. When the connecting line passes through the two tooth tops of the rotor, the oil drainage ends and the smallest tooth cavity appears. In order to ensure the continuous rotation of the rotor, it is necessary to have the same regular oil distribution mechanism to cooperate with it, so that the tooth cavity at the front side of the connecting pipeline is always connected with the oil drain port, and the rear side is connected with the oil inlet port. As mentioned above, the oil distribution mechanism consists of a housing and an oil distribution sleeve. The 12 longitudinal grooves (x) on the oil distribution sleeve and the 12 intervals formed by the oil distribution groove face the root and top of the rotor through the positioning device, which proves that when the largest and smallest cavities occur, the oil distribution hole of the housing can be closed, thus separating the oil inlet groove and oil outlet groove of the oil distribution sleeve.

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 High speed high torque cycloidal hydraulic 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 High speed high torque cycloidal hydraulic 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.

Most of its hydraulic system uses working medium, such as hydraulic oil with continuous fluidity, which converts the mechanical energy of the prime mover driving the pump into the pressure energy of the liquid through the hydraulic pump, and sends it to the actuator (hydraulic cylinder, hydraulic motor or swing hydraulic motor) through various control valves, such as pressure, flow, direction, etc., to convert it into mechanical energy to drive the load. This hydraulic system is generally composed of the following parts: power source, actuator, control valve, hydraulic auxiliary device and hydraulic working medium, which play their respective roles: power source: prime mover (motor or internal combustion engine) and hydraulic pump, whose role is to convert the mechanical energy generated by the prime mover into the pressure energy of liquid, and output oil with a certain pressure;

1. Generally, the motor shall be able to run forward and backward. Therefore, the hydraulic motor is usually required to have structural symmetry in the design. 2. The actual working pressure difference of the hydraulic motor depends on the load torque. When the moment of inertia of the driven load is large and the speed is high, rapid braking or reverse rotation is required, high hydraulic impact will be generated. Therefore, the system should be equipped with necessary safety valves and buffer valves. 3. Under normal working conditions, the inlet and outlet pressure of the hydraulic motor is higher than the atmospheric pressure, so there is no suction performance problem like the hydraulic pump. However, if the hydraulic motor can work under pump conditions, its oil inlet should have a minimum pressure limit to avoid cavitation. 4. Some hydraulic motors must have sufficient back pressure at the oil return port to ensure normal operation. The higher the speed, the greater the back pressure, which indicates that the utilization rate of oil source pressure is not high and the system loss is increased. 5. Because the internal leakage of the motor is inevitable, there will be slow sliding when the hydraulic motor oil outlet is closed for braking. Therefore, when long-term accurate braking is required, a separate anti-skid brake shall be set.