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 plate-type stacking configuration. It is divided into four parts: the mechanical output module, hydraulic function module, oil distribution module, and mechanical braking module, facilitating compatibility with various mainstream optimized supporting systems.

High Efficiency: It adopts flat oil distribution technology, which has low sensitivity to pressure and temperature. This technology automatically compensates for wear between the oil 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 processes, significantly increasing the operating pressure of the hydraulic motor, with a maximum pressure of up to 40 MPa. Due to the low inertia of the force transmission mechanism, the plunger pair is equipped with a sealed piston ring, and the roller stopper is made of friction-reducing material, the motor achieves high starting efficiency and excellent low-speed performance.

Ability to Withstand Radial and Axial Loads: With an independently arranged 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 plate-type structure, which allows 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 categorized into single-displacement motors and dual-displacement motors. Single-displacement motors operate with full displacement output. Dual-displacement motors can realize both full-displacement and half-displacement output through control valve regulation, enabling speed control.

A radial piston hydraulic motor that uses a cam ring with a unique curve to make each piston perform repeated linear movements several times for each revolution of the cylinder block is called a multi-functional internal curve radial piston hydraulic motor (referred to as an internal curve motor for short).

Internal curve motors have the advantages of small size, light weight, balanced radial force, small torque ripple, high operating efficiency, and stable operation at very low speeds. They are widely used in marine accessories.

Working Principle of the Internal Curve Motor

The inner cavity of the cam ring (housing) is composed of x evenly distributed curved surfaces with identical shapes. Each curved surface of the same shape can be further divided into two symmetrical sides: the side that allows the piston assembly to extend outward is called the working segment (oil inlet segment), and the symmetrical opposite side is called the oil return segment.

The number of reciprocating movements of each piston during one revolution of the hydraulic motor is equal to the number of curved surfaces x of the cam ring (where x is called the "acting frequency" of the motor).

The cylinder block (2) has z evenly distributed radial piston holes along its circumferential direction. The bottom of each cylinder hole is provided with an oil distribution window, which is connected to the oil distribution hole of the oil distribution shaft (4).