Its basic types are gear type, screw type, vane type and axial plunger type. Its main characteristics are high speed, small moment of inertia, convenient starting and braking, adjustment (speed adjustment and special-purpose Crane cycloid motor Reversing) High sensitivity. As the output torque of high-speed hydraulic motor is generally small, it is also called high-speed small torque hydraulic motor. Its basic type is radial plunger type, in addition, there are axial plunger, vane type, gear type and other structural types. Low speed hydraulic motors are mainly characterized by large displacement, large volume and low speed (sometimes Crane cycloid motor manufactor It can rotate a few revolutions per minute or even a few revolutions per minute), so it can be directly connected to the working mechanism; It does not need a speed reducer, greatly simplifying the transmission mechanism. Usually, the output torque of low-speed hydraulic motor is large, so it is also called low-speed high torque hydraulic motor.

Cycloidal hydraulic motor structure: the internal meshing gear pair consisting of rotor and stator, cycloidal needle wheel, as the meshing pair, has a torque generating part. The stator, together with the spacer and the rear cover, is fixed on the housing to form seven cavities that are only connected with the oil holes on the housing one by one. A distribution mechanism consisting of an oil distribution sleeve and a housing. Two oil distribution sleeves Anyang Crane cycloid motor The ring groove is respectively connected with the oil inlet and return ports of the housing, and its longitudinal groove has twelve oil ports, Crane cycloid motor manufactor Six oil ports and the oil distribution hole of the housing form the oil distribution link. The splines at both ends of the linkage shaft are respectively connected with the rotor and the output shaft, which is used to transmit torque and ensure that the oil sleeve is synchronized with the output shaft. The function of the output shaft is to output the torque generated by the rotor through the linkage shaft and drive the oil distribution device to rotate synchronously.

The hydraulic motor has two circuits: the hydraulic motor series circuit and the hydraulic motor braking circuit. These two circuits can be classified into the next category. One of the series circuits of hydraulic motors: three hydraulic motors are connected in series with each other, and a reversing valve is used to control the start stop and steering. The flow through the three motors is basically the same. When the displacement is the same, the speed of each motor is basically the same. The oil supply pressure of the hydraulic pump Anyang manufactor High, small pump flow, generally used for light load and high speed. Serial circuit II of hydraulic motor: each reversing valve in this circuit controls one motor, each motor can work independently or simultaneously, and the rotation direction of each motor is also special-purpose Crane cycloid motor optional. The oil supply pressure of the hydraulic pump is the sum of the working pressure difference of each motor, which is applicable to the condition of high speed and small torque.

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 special-purpose 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 Anyang 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.

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 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 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.