The valve control system controls the flow by changing the opening of the valve throttle, thus controlling the speed of the actuator. Usually, the reason for low efficiency is the existence of throttling and overflow losses. Almost all mechanical equipment adopts valve control system. The pump control system can realize the stepless control of speed by changing the displacement of variable displacement pump, or control the flow through the combination of multiple constant displacement pumps to achieve the stepwise control of speed. The reason for high efficiency is that there is no throttling or overflow loss. It is widely used in high power hydraulic devices such as pressure processing machinery and plastic machinery. The actuator control system controls the flow by changing the variable hydraulic motor flow of the actuator, or through the joint work of multiple quantitative hydraulic motors, or by changing the action area of the composite hydraulic cylinder. Similar to the pump control system, this system has high efficiency because it has no throttling and overflow losses. It is suitable for traveling machinery, press and other hydraulic equipment.

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.

System for fixed equipment. This hydraulic system is mostly an open cycle system, including machine tools (workpiece clamping, worktable feeding, direction exchange, spindle drive), presses (pressing, blank holder, direction exchange, workpiece ejection), die-casting machines and injection molding machines (mold closing, demoulding, preforming, injection mechanisms), medical devices, garbage compression and other mechanical devices Wuhu special-purpose System of standby and working devices. The hydraulic system for traveling equipment includes both open circulation system and closed circulation system, including vehicle driving (traveling drive, steering, braking and working equipment Cycloidal hydraulic motor brake manufactor ), material conveying, loading, unloading and conveying equipment (conveying mechanism, transposition mechanism), various systems of aviation, space and navigation engineering.

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 Cycloidal hydraulic motor brake 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 Cycloidal hydraulic motor brake manufactor 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.

If the hydraulic system is compared to the human body, then the hydraulic oil is equal to human blood. In the hydraulic system, the hydraulic oil plays a role in energy transmission, system lubrication, and prevention Wuhu Cycloidal hydraulic motor brake The functions of corrosion, rust prevention and cooling, and whether the hydraulic system can work effectively are closely related to the type and selection of hydraulic oil. Coding, composition and characteristics of hydraulic system: high purity general machine tool oil, refined mineral lubricating oil, with good rust resistance and oxidation resistance. High wear resistant hydraulic oil, refined mineral lubricating oil, rust proof, anti-oxidation, anti-wear. High temperature and high pressure hydraulic oil, with the characteristics of rust prevention, oxidation resistance, wear resistance, etc., is refined into mining lubricating oil, and added with viscosifier. Refined mining lubricating oil HG hydraulic guide oil, rust proof, anti-oxidation, anti-wear, anti stick slip. HS synthesis special-purpose Cycloidal hydraulic motor brake Hydrocarbon is a kind of low temperature hydraulic oil, which has the characteristics of anti-oxidation and anti-wear.

1. Air intrusion. When the air intrudes into the hydraulic system, it has a large volume in the low-pressure area. When it enters the high-pressure area, it is compressed, and the volume suddenly decreases. When it enters the low-pressure area, the volume suddenly increases, resulting in a sudden change in the bubble volume, that is, "explosion" phenomenon, resulting in noise. Solution: Generally, the hydraulic cylinder is equipped with an exhaust device special-purpose Cycloidal hydraulic motor brake Exhaust. In addition, a common method is to exhaust the actuator several times during the fast full stroke after startup. 2. The quality of the hydraulic pump or motor is poor. The quality of the hydraulic pump is poor, the accuracy does not fully meet the technical requirements, the pressure and flow fluctuations are large, the oil trapping phenomenon has not been eliminated well, and poor sealing and poor bearing quality are the main reasons for the noise. In use, due to wear of hydraulic pump parts, excessive clearance, insufficient flow Wuhu manufactor The force is easy to fluctuate and will also produce noise.