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 special-purpose OM cycloidal 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 OM cycloidal motor Price 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 oil distribution sleeve is synchronized with the rotor, so that the rotor rotates once, and the seven oil distribution holes on the housing are closed 840 times by the twelve diaphragms of the oil distribution sleeve, while the rotor and stator form the largest and smallest closed cavities respectively 1420 times, collectively referred to as the seal cavity. In the circle of the oil distribution hole of the closed housing, the oil inlet and outlet of the rotor have three chambers respectively, one Guilin OM cycloidal motor The cavity is closed. When the rotor is transferred from the smallest enclosed cavity to the next largest enclosed cavity, before the rotor is transferred from the largest enclosed cavity to the next smallest enclosed cavity, oil is supplied to four cavities and three cavities special-purpose OM cycloidal motor Drain the oil.
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), Guilin OM cycloidal 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, special-purpose OM cycloidal 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.
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 special-purpose OM cycloidal 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 Guilin special-purpose 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.
As a kind of hydraulic transmission device, hydraulic motor has been widely used in many places. In fact, I have seen it on many occasions. The main application fields are. 1. The hydraulic motor has convenient speed regulation, which can be adjusted infinitely from 0 to the maximum speed according to the adjustment of the hydraulic valve. The motor itself does not need special design and has low cost. This is much cheaper than motor+reducer, or variable frequency motor and servo motor. 2. The hydraulic system has strong anti overload capacity and relies on the overflow valve for protection, allowing a long time special-purpose OM cycloidal motor (Relatively) Frequent overload, easy to recover under overload, no damage to equipment, no restart of equipment. 3. The hydraulic system is characterized by high energy density. For motors of the same power, hydraulic motors are much smaller than motors OM cycloidal motor Price , much lighter. And it is easy to apply to mobile devices. 4. The hydraulic motor is totally enclosed and can be safely used in dusty, wet (even underwater) and flammable environments, which is much more reliable than explosion-proof (flameproof) motors.
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.
