4707477 Hitachi excavator ZX220W-5B travel motor

Part number 4707477 is a dedicated travel motor assembly (including two-speed axial piston motor + two-stage planetary gearbox + wheel hub drive mechanism) for Hitachi ZX220W-5B wheeled excavators, compatible with ZX220W-5B and models on the same platform such as ZX220W-5. It is suitable for Isuzu 4HK1 engines and HIOS III hydraulic systems. The motor has a rated pressure of 32MPa, a maximum torque of 6800N·m, a reduction ratio of 19.8:1, an input speed of 0-3000rpm, and an output speed of 0-151rpm. The total weight of the assembly is about 180kg. It adopts double-row lip oil seal + dust ring, with a protection class of IP65, and is suitable for 315/70 R22.5 standard tires, ensuring stable power output for wheeled excavator road transfer and construction site travel.

Its core function is to convert the high-pressure oil from the hydraulic pump into wheeled travel driving force. The two-stage planetary gearbox realizes large torque output. The motor has a built-in balance valve (to prevent slope slipping/braking) and an overload relief valve (to protect the system pressure ≤35MPa). The double-row oil seal isolates hydraulic oil from gear oil, preventing dust, water and leakage. The gears are made of 20CrMnTi material (carburizing and quenching hardness HRC58-62), and the bearings are original NSK (rated service life ≥10000 hours). It is suitable for working conditions such as road transfer and municipal construction (operating temperature -30℃ to 80℃), with an average service life of ≥8500 hours. It has a fast forward-reverse switching function (response time ≤0.5s), ensuring stable and accurate travel of the wheeled excavator and reducing component wear.

Before replacement, disconnect the negative pole of the battery and release the pressure of the hydraulic system. When disassembling, remove the wheel hub fixing bolts with a torque of 110-130N·m, mark the oil pipe interfaces (to avoid wrong connection), and clean the mounting surface (free of oil stains and impurities). When installing, replace with a new oil seal (apply grease), tighten the bolts symmetrically (110-130N·m), add gear oil (API GL-5 85W-90) to the oil level line after connecting the oil pipes, and perform a test run (10 minutes each for forward and reverse rotation, no abnormal noise/leakage). This travel motor can increase the wheeled excavator transfer speed by 15%, reduce travel failure shutdown rate by 30%, decrease hydraulic oil loss by 10%, extend the service life of tires and wheel hubs, improve the overall operation efficiency of the machine, and reduce maintenance costs.