EX120-1 Komatsu Swing Motor Gearbox 9118328 Swing Reducer Gearbox

Core Structure Description

• Sun gear: Splined engagement with slewing motor shaft for high-speed power input.
• Planet gear: Each stage equipped with 3 to 4 planet gears, executing planetary motion to transmit torque.
• Ring gear: Stationary fitted on reducer housing, maintaining standard meshing with planet gears.
• Planet carrier: Serves as final power output component to drive the pinion gear at the bottom.
• Brake: Integrated wet-type multi-disc brake; relies on spring force for braking and hydraulic pressure for release to prevent inertial slewing.
• Housing and bearing assembly: Adopts high-strength alloy steel casting or forging, matched with heavy-load bearings, with reliable dustproof, waterproof and oil-sealing performance.

Working Principle Description

Common Faults and Root Cause Analysis

• Abnormal noise and operation stuttering: Gear surface wear, pitting corrosion, bearing damage and failure, insufficient lubricating oil or oil contamination, abnormal gear meshing clearance.
• Lubricant leakage: Oil seal aging and deterioration, reducer housing cracking, excessive lubricant filling height, breather valve blockage and failure.
• Slewing weakness and slow rotation speed: Gear or bearing severe wear, brake cannot be completely released, hydraulic motor internal leakage, unreasonable transmission speed ratio matching.
• Overheating failure: Lubricant shortage or oil deterioration, long-term overload operation, brake long-term dragging friction, poor heat dissipation condition of reducer.
• Gear jumping phenomenon and gear tooth breakage: Sudden impact load, foreign impurities entering the gear chamber, long-term mechanical fatigue wear, installation and assembly misalignment.