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QJM Sphere Piston Hydraulic Motor
Product Details

QJM Sphere Piston Hydraulic Motor

QJM hydraulic motor that can constitute a hydraulic actuator with different oil pumps, valves and hydraulic parts is able to adapt itself to all kinds of mechanical conditions by reason of some measures taken to its design. The motor has many advantages, e.g. light weight, small size,

wide speed regulating range, capable of stepping variation, reliable performance and long useful life, etc. It has been widely applied for mine

engineering, hoisting transport, metallurgy, ships, machine tools, plastics processing and geological prospecting, etc. It is mainly used for pedrail

walking, driving railway wheels, different stewing gears, drilling, winch hoisting, belt transmission, material agitation, cutting road surfaces, ship

propulsion, plastics injection, etc.


1、Because the rolling body of this motor is replaced by a steel ball rather than two or more rollers and beams commonly used in inner curve

hydraulic motors, it is simple in structure, reliable in performance and greatly reduced in volume or weight.

2. A small kinematic pair inertia and a hard steel ball make this motor continuously work during the rotation at higher speed and under stronger impact load.

3. It has higher mechanical and volumetric efficiency for its small friction pair, oil feed shaft balanced with roller, piston pair capable of static pressure balance & good lubrication and coated high pressure sealing oil on soft plastic mat.

4. As the oil feed shaft and stator are in rigid connection, the oil pipeline of this model can be connected with steel pipe.

5. As this model has variable displacements dual and trinal speeds, it is wider in speed regulating range.

6. Simple structure and easy maintenance

7. The output shaft of the standard model can only endure the torque rather than outside radial and axial forces, while that one of Z series hydraulic motor can endure outside radial and axial forces

8. As T series hydraulic motor has a central through hole, the rotating shaft can pass through the motor.



As shown in figure, the oil feed shaft and rear cover of QJM hydraulic motor (standard) are in rigid connection, the roller is supported in radial direction by the oil feed shaft, and in axial direction by the stator groove and steel ball (without bearings), and its output shaft is the inner spline (in loose coordination with the input shaft of its operation mechanism), so the roller is fluctuating while the oil feed shaft is rigid (allowed to be connected with the steel pipe). The hydraulic oil is fed to the oil feed opening to high-pressure cavity through the oil feed shaft channel (or the speed change valve), then the oil enters into every piston cylinder bore to make the piston actuate the ball steel to act on the stator in N for pressure.

Meanwhile, the stator acts on the steel ball in a counterforce N' the same as N, then the steel ball actuates the piston to act on the roller in a tangential force F.


Therefore, the roller rotates around the oil feed shaft in F, then a large torque is caused by the rotation of several pistons at the same time,influenced by the pressure oil.

When the piston rotates to the top of the stator displacement curve around the roller, the piston begins to return to the shaft center, and working oil in the piston cylinder is pushed back into the low pressure cavity through the oil feed shaft opening. Thus, the hydraulic energy is transformed into mechanical energy again and again for repeated operations.

By changing the oil flow direction of two oil feed openings, positive and negative rotations can be realized.

The stepping variable displacement of the hydraulic motor is controlled by the speed change valve (installed in the motor) that can be controlled by hand or the pilot-actuated valve, and also fixed in a position, which makes the motor into a fixed displacement motor (the requirements changed to the fixed displacement motor or manual control should be indicated in the contract). When the motor is controlled by the pilot-actuated valve, the pressure for controlling the oil pipeline should be within the range from 0.3 to 10Mpa.