4638802 Original Excavator Bushing for ZX870-3 ZX870-5G ZX890-5A ZX870-5B ZX89-6A ZX890-7

This high-performance wear-resistant liner is specially customized for the front-end working devices of Hitachi's large and ultra large excavators. The product is manufactured with high precision in strict accordance with Hitachi's official part number 4638802, and is widely used in heavy-duty mining excavator series such as Hitachi ZX850LC-3, ZX870H-3, ZX870LCH-3, and ZX850LD-3. This bushing is mainly used in the core hinge parts of the boom, stick, and connecting rod mechanism. Standardized physical tolerance design ensures full compatibility with original factory pin shafts and sealing components, ensuring precise fit clearance and excellent mechanical synergy between the joints of the working device when subjected to high-frequency heavy load impacts.

The liner is made of high-quality high carbon alloy structural steel (such as 20CrMnTi or 40Cr) as the base material, and has undergone precise overall forging and heat treatment processes. The advanced digital microporous oil groove design is integrated into its inner wall, greatly improving the storage and diffusion efficiency of lubricating grease. The surface of the product has undergone deep carburizing or high-frequency quenching treatment, giving it the physical characteristics of "external hardness and internal toughness" - high surface hardness, excellent resistance to adhesive wear and abrasion; The core has strong toughness and can effectively absorb the reverse severe impact from the excavation of hard rocks in mines. The rigorous fatigue and deformation tests endow this component with extremely high structural stability.

Due to the long-term exposure of the working equipment of large excavators to heavy load alternating stress, the later maintenance of the lining must strictly follow the lubrication principle of "fixed quality, quantity, and timing". In daily operations, it is necessary to ensure the normal operation of the centralized lubrication system or to manually add high viscosity molybdenum disulfide grease regularly to forcibly remove internal foreign objects and maintain oil film thickness. Regularly check the radial clearance between the bushing and the pin shaft. Once the unilateral wear exceeds the original factory safety limit, it should be replaced in a timely manner to prevent excessive clearance from causing unilateral unbalanced load and damaging the working device body. Maintaining the integrity of the dust-proof ring at the hinge joint can significantly block the intrusion of high entropy sand and gravel particles.