Created on:2021-05-24 09:34

Typical structure of multi action radial piston motor

Typical structure of multi action radial piston motor

This kind of motor is often equipped with cam ring with special inner curve, so it is also called inner curve motor for short. There are many kinds of motors. This paper introduces several typical structures.

① Figure D shows the structure of ball plug motor. A ball plug pair composed of a plurality of steel balls 1 and a ball holder 5 is evenly arranged on the rotor 2, and the force is transmitted through the ball holder; the valve distribution mechanism of the motor is the valve distribution shaft 4. The main structural features of this kind of motor are as follows: the plunger, piston, cross beam, roller and other parts of general radial piston motor are replaced by steel ball and ball bracket, so the structure is simple and the cost is low; because the steel ball is a mass-produced product of bearing factory, the supply quantity is sufficient and the precision is high; the inertia of motion pair is small, the steel ball is firm and reliable, and it is resistant to impact, which is conducive to improving the speed and the impact load The ball piston pair is made of self-lubricating composite material, which has static pressure balance and good lubrication conditions, and the steel ball basically has no wear; the soft plastic piston ring which can automatically compensate the wear is used to seal the high-pressure oil, which improves the hydraulic mechanical efficiency and volumetric efficiency of the motor, improves the low-speed stability and increases the starting torque. Due to the rigid connection between valve distribution shaft 4 and stator, the oil inlet and outlet of the motor are allowed to be connected by steel pipes.


② Figure e shows the structure of roller type inner curve motor. The plunger 4 is connected with the crossbeam 2 through the connecting rod 3. There are four rollers on the crossbeam. Two rollers 5 in the middle contact with the guide rail curve 6, and the other two rollers 1 on the outside roll in the guide groove of the cylinder block 7 and transfer the tangential force at the same time. Because the motor is a shell rotating hydraulic motor, the cylinder block 7 does not rotate, but the shell connected with the guide rail curve 6 as a whole rotates. The belt brake can be installed on the cylindrical surface of the shell.


③ Figure f shows the structure of the cross beam internal curve motor. In this kind of motor, the force is transmitted to the cross beam 4 by the plunger 3, and the cross beam can slide in the radial groove of the cylinder block 2, so the tangential force is transmitted to the cylinder block by the cross beam, forcing the cylinder block to rotate. The top of the plunger is a spherical surface or a conical surface, which is in contact with the crossbeam, so the plunger can transmit the hydraulic pressure to the crossbeam, but the tangential force on the crossbeam can not be transmitted to the plunger. The plunger only bears the hydraulic pressure, and there is no lateral force. In this way, not only the leakage of high-pressure oil between the plunger and the plunger hole is reduced, but also the wear between the plunger and the plunger hole is reduced, which not only improves the volumetric efficiency, but also prolongs the service life. The correct phase between valve distribution shaft 1 and guide rail curve can be adjusted by fine-tuning screw 8 to achieve accurate valve distribution and reduce noise.


From the principle and stress analysis, all kinds of hydraulic motors can be made into shell rotation and shaft does not move, or shaft rotation and shell does not move.

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