PC300-7 PC360-7 Komatsu Gearbox Final Drive Gear Reducer Box

Core Structure

• Sun gear: Splined connection with the slewing motor for high-speed power input.
• Planet gear: 3–4 gears per stage, performing both orbital rotation around the sun gear and autorotation for torque transmission.
• Ring gear: Stationary on the housing and constantly meshed with planet gears.
• Planet carrier: Serves as power output component to drive the bottom pinion gear.
• Brake: Built-in multi-disc wet brake; spring engages braking while hydraulic pressure releases it to prevent free slewing.
• Housing and bearings: High-strength cast/forged steel construction, heavy-load bearing support, excellent dust and oil leakage resistance.

Working Principle

Common Faults & Causes

• Abnormal noise and intermittent operation: Gear surface wear and pitting, bearing damage, insufficient or dirty lubricant, unreasonable gear meshing gap.
• Lubricant leakage: Seal aging, housing fracture, overfilling of gear oil, breather valve clogging.
• Slow and powerless slewing: Gear or bearing abrasion, incomplete brake release, hydraulic motor internal leakage, unmatched transmission ratio.
• Excessive temperature rise: Oil shortage or deterioration, overloading, brake continuous friction, insufficient heat dissipation.
• Gear skipping and tooth fracture: Shock load impact, internal foreign matter, long-term fatigue wear, mounting position deviation.