Product Features

The YMS hydraulic motor is an internal-curve, multi-acting radial piston motor. Its main features are as follows:

Modular Design: The overall structure adopts a modular design with a chip-type stacking configuration. It is divided into four parts: the mechanical output module, hydraulic function module, flow distribution module, and mechanical braking module. This design facilitates compatibility with various mainstream optimized supporting systems.

High Efficiency: It adopts flat valve flow distribution technology, which has low sensitivity to pressure and temperature. This technology automatically compensates for wear between the flow distribution friction pairs, ensuring the motor maintains high volumetric efficiency for a long time. Meanwhile, the adoption of a roller-plunger structure simplifies the force transmission mechanism and improves mechanical efficiency.

High Operating Pressure and Excellent Low-Speed Performance: The stator curve design has been optimized to ensure output torque and stable rotational speed while reducing stator contact stress. Additionally, the stator is manufactured using new materials and advanced processes, significantly increasing the hydraulic motor’s operating pressure—with a maximum pressure of up to 40 MPa. Owing to the low inertia of the force transmission mechanism, the plunger pair equipped with a sealing piston ring, and the roller stopper made of anti-friction material, the motor achieves high starting efficiency and excellent low-speed performance.

Capability to Withstand Radial and Axial Loads: With an independently configured mechanical output module, as well as a large-diameter output shaft and bearings, the motor can withstand large axial and radial forces. It can be directly connected to a gear output or installed directly on the drive wheel of a vehicle.

Optional Mechanical Brake: It adopts a modular chip-type structure, allowing the integration of a mechanical braking device to achieve direct and safe service braking and parking braking of the output shaft.

Motor Displacement Control: Motors are available in two types: single-displacement motors and double-displacement motors. Single-displacement motors output full displacement, while double-displacement motors can switch between full-displacement and half-displacement output via control valve regulation to achieve speed control.

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Flow rate is equivalent to the product of displacement and rotational speed. The actual flow rate refers to the flow rate at the outlet (for hydraulic pumps) or inlet (for hydraulic motors) during their operation. Due to internal leakage in the hydraulic pump (or motor) itself, the actual flow rate is lower than the theoretical flow rate. To achieve a specific rotational speed of the motor, the actual input flow rate must be higher than the theoretical flow rate to compensate for the leakage.

The efficiency of a hydraulic pump (or motor) is divided into volumetric efficiency and mechanical efficiency:

Volumetric efficiency: For a hydraulic pump, it refers to the ratio of the actual flow rate to the theoretical flow rate; for a hydraulic motor, it refers to the ratio of the theoretical flow rate to the actual flow rate. The theoretical calculation formula is as follows:[Note: If the original text included specific formulas, they should be inserted here, e.g., "ηᵥ (pump) = Qₐ / Qₜ × 100%; ηᵥ (motor) = Qₜ / Qₐ × 100%" where ηᵥ = volumetric efficiency, Qₐ = actual flow rate, Qₜ = theoretical flow rate]

Mechanical efficiency: For a hydraulic pump, it refers to the ratio of the theoretical torque to the actual input torque; for a hydraulic motor (including double-shaft hydraulic motors), it refers to the ratio of the actual output torque to the theoretical torque. The theoretical calculation formula is as follows:[Note: Insert specific formulas if provided, e.g., "ηₘ (pump) = Tₜ / Tₐ × 100%; ηₘ (motor) = Tₐ / Tₜ × 100%" where ηₘ = mechanical efficiency, Tₜ = theoretical torque, Tₐ = actual torque]

The total efficiency refers to the ratio of the output power to the input power of the hydraulic pump (or motor), which is equal to the product of the volumetric efficiency and the mechanical efficiency.