Kayaba Hydraulic Swing Motor MSG-27p MSG-44P-21E MSG-63P KYB For Excavator

MSG Rotary Motor Product Introduction

1, Product Overview
· The MSG series integrates hydraulic motors, mechanical brakes, buffer valves, and flushing valves into one, providing a fully functional rotary drive solution.
· Core technology: Adopting an internal curved radial plunger design, which is the key to achieving its ultra-high performance.

2, Working principle and core design
1. Internal curve radial plunger mechanism:
· There is a fixed cam ring (stator) inside the motor, and its inner surface is composed of multiple curves.
· The plunger on the rotor extends under the action of pressure oil, and the roller at its end is tightly attached to the curved track of the cam ring.
· High pressure oil drives the plunger, and the roller moves on a curved track. Due to the reverse force of the track, it drives the rotor to generate rotational torque.
· This multi plunger and multi action design enables the MSG motor to output extremely smooth and huge torque.
2. Integrated design:
· Normally closed multi disc brake: spring brake, hydraulic release. Safe and reliable, it can automatically lock the rotating platform in case of power outage or shutdown to prevent accidental movement.
· Buffer valve (overload oil replenishment valve): integrated at both ends of the motor, used to absorb pressure peaks caused by starting, stopping, or external impacts, protecting the motor and the entire hydraulic system.
· Flush valve (hot oil exchange valve): used to extract and return the heat leakage oil inside the motor to the oil tank, while replenishing cold oil, effectively controlling the working temperature of the motor and extending the life of the seals and oil.

3, Core product features
1. Extremely high starting efficiency and torque: The internal curve design allows for a starting efficiency of over 98%, enabling smooth start-up under load and providing enormous starting torque.
2. Excellent low-speed stability: Even at extremely low speeds (<1 rpm), it can output very smooth, non crawling rotational motion with high control accuracy.
3. Strong impact resistance: The integrated buffer valve can effectively absorb system impacts, making it particularly suitable for frequent start stop and external load impact scenarios such as excavators and cranes.
4. High power density: With relatively compact structural dimensions, it can output very large torque, saving installation space.
5. Long service life: The sturdy bearing design, optimized friction pairs (such as rollers and curved tracks), and effective thermal management (flushing valves) make it extremely durable.
6. High rigidity: With its sturdy structure and internal bearing design, it can withstand huge radial and axial loads.
Rotary worktable, etc.

4, Main technical parameters (taking typical models as examples)
Parameter project scope/example explanation
The displacement range is from~160 mL/r to~2000 mL/r, covering a wide range of equipment from small and medium-sized to ultra large, with corresponding models available
Rated working pressure 35 MPa (350 bar)
The maximum working pressure of 40 MPa (400 bar) reflects its heavy-duty design
Peak pressure 45 MPa (450 bar) buffer valve opening pressure, used to absorb impact
Brake release pressure~2.5-3.5 MPa (25-35 bar)
The output torque is extremely high (up to tens of thousands of Newton meters), and the specific value depends on the displacement and working pressure
Minimum stable speed<1 rpm 

5, Typical application areas
MSG rotary motor is the preferred choice for many heavy construction machinery, commonly used in:
· Excavator: As the core of the slewing mechanism, it drives the loading platform to rotate 360 °.
· Cranes: Rotary mechanisms for truck cranes, all terrain cranes, and crawler cranes.
· Ship and Ocean Engineering: Deck Cranes, Winches, Propulsion Rotary Mechanisms.
· Mining machinery: Rotary drive for underground loaders, mining equipment, etc.
· Other: Tunnel boring machine, radar antenna drive, heavy