HMJC125 High-Efficiency Motor for Industrial Use

HMJC125 two-speed motor has two preset displacements to choose from a wide range to suit specific application requirements. Control and selection is made via directional valve. The displacement can be easily changed while the motor is running. Double-sided main port design, more convenient for hydraulic motor control valve layout.

HMJC125 is a two-speed axial piston hydraulic motor (often referred to as a "two-speed motor"), part of the HMJ series (two-speed variable speed motors). Its core feature is the ability to switch between two speed/torque modes through mechanical shifting, making it widely used in applications requiring switching between "high speed with light load" and "low speed with heavy load."

HMJC125 two-speed motor achieves efficient power switching through mechanical shifting, making it an optimal alternative to "single-speed motor + multi-valve manifold" systems. It is particularly suitable for applications such as crawler machinery and mining transportation that require a clear combination of "low speed, high torque, and high speed with light load."

HMJC125 two-speed hydraulic motor is a high-performance, versatile hydraulic motor featuring a two-speed design, excellent speed regulation, and a wide range of applications. It is an ideal choice for a variety of industrial applications, providing powerful power support for machinery and meeting diverse load requirements.

HMJC125 Hydraulic Motor Working Principle

The HMJC125 is a radial piston-type dual-speed variable displacement hydraulic motor, a copy of the Kawasaki Staffa HMC125. Its core structure includes: an eccentric cam, piston-cylinder assembly, distribution shaft, dual-speed shifting mechanism, and output shaft.

Basic Low-Speed, High-Torque Working Principle (Large Displacement Gear):

High-pressure oil enters the corresponding piston chamber in the cylinder through the distribution shaft, pushing the piston outwards.

The piston head presses against the fixed eccentric cam ring surface. The eccentric cam has an eccentricity, and the piston experiences a reaction force from the cam, generating a tangential thrust.

Multiple sets of pistons rotate in succession, driving the cylinder to rotate. The cylinder directly drives the output shaft to output torque; low-pressure oil is discharged back to the oil tank via the distribution shaft.

The greater the eccentricity, the larger the displacement, the higher the output torque, and the lower the speed.

Essentially: Hydraulic pressure → piston thrust → cam tangential force → cylinder rotation outputs mechanical energy.

Dual-speed transmission principle (HMJC core feature: large displacement switching)

This motor has two displacement settings: large displacement 2048ml/r and small displacement 507ml/r. Speed change is achieved by changing the effective eccentricity using an internal shift piston, eliminating the need for an external gearbox.

Large displacement setting (low speed, high torque): The shift control oil is pressureless, and the internal eccentric mechanism is at its maximum eccentric position. All plungers participate in the work, resulting in maximum displacement, maximum torque, and low speed, suitable for heavy-duty applications such as winch hoisting and ship hoisting.

Small displacement setting (high speed, low torque): Control pressure oil is supplied to the external shift control port, pushing the internal shift piston and moving the eccentric ring to its smallest eccentric position.

Only some plungers participate in the work, resulting in a smaller effective displacement; at the same flow rate, the speed increases significantly, while the output torque decreases, suitable for light loads and rapid deployment.

Switching can be done online under load; avoid frequent shifting under extreme high-pressure impacts.

Distribution Shaft Principle: The distribution shaft remains stationary, while the cylinder block rotates following the output shaft. The distribution shaft has high-pressure and return oil windows. As the cylinder block rotates, each plunger cylinder sequentially connects to the high-pressure inlet and low-pressure return oil, automatically completing the oil intake and exhaust cycle to ensure continuous motor rotation.

Key Features Summary: Radial plunger + cam structure, excellent low-speed performance, allowing for smooth rotation at very low speeds; Dual speed is achieved through internal variable displacement, not by changing the external oil supply flow; Output torque is proportional to system pressure; Speed is determined by both input flow rate and current actual displacement.