PC300-8MO PC350-8MO PC390-8MO Excavator Swing Motor Swing Gearbox Swing Device High Quality Swing Assembly

This high-precision heavy-duty swing motor gearbox assembly (Swing Assembly) is the core center of the vehicle's fluid power drive and precise rotation. This top-level rotary drive device is specially designed for the aftermarket of Komatsu's classic heavy-duty hydraulic excavator, perfectly matching core mining and earthmoving star models such as PC300-8M0, PC350-8M0, PC360-8M0, and PC390-8M0 in the 30 to 40 ton industry. The product is based on first principles optimization of ultra-high pressure rotary plunger components and multi-stage high torque planetary reduction gear system, seamlessly bearing the alternating shear stress caused by frequent starting and braking of large inertia, ensuring absolute certainty of rotary propulsion torque. The physical dimensions of the product packaging are approximately 580mm × 580mm × 880mm, with an overall net weight of approximately 245kg. The original factory standard hole positions are precisely aligned.

"Extreme cleaning and torque tightening: Before lifting and docking, the installation surface of the turntable base and the large gear ring of the slewing support must be kept absolutely flat and free of any foreign objects or rust. All high-strength fastening bolts must be tightened using torque wrenches, strictly following the factory's specified torque for symmetrical and phased cross tightening to prevent local abnormal shear stress.

Forced bidirectional oil injection between motor and casing (core avoidance pit): Do not connect the wrong drain pipe (Case Drain) when connecting hydraulic pipelines. Before starting the engine, clean hydraulic oil must be filled from the oil injection port at the top of the rotary motor; At the same time, increase the load gear oil from the reducer filling port to the standard line on the dipstick. It is strictly prohibited to start dry grinding, otherwise the rotating components will undergo irreversible physical erosion within 3 seconds of ignition.

No load micro exhaust transition: After the first start-up, control the upper body to rotate at a small angle and slow speed alternately for 10-15 minutes in a no-load state, thoroughly exhaust the air inside the circuit, and closely monitor the gear meshing sound. Only after confirming that the thermodynamic state of the entire system is stable can normal operating loads be gradually applied."