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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Displacement refers to the volume of fluid discharged (for hydraulic pumps) or sucked in (for hydraulic motors) by the geometric volume change of the sealed chamber when the hydraulic pump (or motor) completes one full rotation, with the unit of ml/r (milliliters per revolution). Pumps (or motors) whose displacement can be adjusted are called variable-displacement pumps (or motors), while those whose displacement cannot be changed are called fixed-displacement pumps (or motors).

To determine the displacement of a hydraulic pump (or motor), it is necessary to introduce the concept of angular power. Angular power is a descriptive index for an extreme state; it is not a power that can be generally obtained (e.g., for a connecting-rod hydraulic motor), but it effectively and comprehensively reflects the transmission capacity of a drive system—specifically, the power density and conversion capacity of the drive system. Angular power is equal to the product of the maximum output torque and the maximum rotational speed of the drive system. When the torque is high, the rotational speed is low, and the two cannot reach their peak values simultaneously; therefore, angular power cannot be actually achieved. However, if a hydraulic transmission system has the angular power capacity required by the dedicated working equipment, a torque-speed point that meets the requirements (one being the required maximum torque point and the other being the required maximum rotational speed point) can usually be found during the adjustment and conversion process of its two key parameters: torque and rotational speed.

A hydraulic pump and a hydraulic motor can be selected based on the determined operating pressure, rotational speed, and displacement of the hydraulic pump (or motor).