3070250 Original Excavator Center Joint Ring for Hitachi ZX330-3

The Hitachi original excavator center joint ring (universal part number: 3070250) is a key annular component inside the center swivel joint (or center swivel body). The central rotary joint is the core assembly that enables the excavator to achieve 360 degree infinite relative rotation between the upper frame (cab and working device) and the lower frame (chassis), while maintaining smooth hydraulic oil flow. As a precision component, this joint ring is widely compatible with multiple series of hydraulic excavators from Hitachi, including the ZX series (such as ZX200, ZX250, ZX330, etc.), EX series (such as EX1200, EX2600, etc.), and some wheel excavators.

The central joint ring is the core component that ensures the sealing performance and smooth rotation of the central rotary joint. Inside the central rotary joint, it is usually used as a sealing ring, spacer ring, or positioning ring, installed between the core shaft and the housing. Its core function is to separate different hydraulic oil channels (such as walking, rotating, etc.) and prevent high-pressure oil from colluding or leaking out between each oil channel. As an original component, it is manufactured using high-quality materials that meet strict engineering machinery standards, such as special engineering plastics with excellent wear resistance (such as POM), bronze, or alloy steel with specially treated surfaces. Its dimensional accuracy is extremely high, capable of withstanding high pressure (usually up to 35MPa or higher) and sustained relative rotational friction of hydraulic systems.

The maintenance core of the central joint ring is to prevent leakage and abnormal wear. Firstly, it is recommended to regularly (every 500 working hours or in conjunction with regular maintenance) inspect the central rotary joint area for oil stains, which is the most direct sign of internal seal failure (including joint rings and related seals). Secondly, in daily operations, avoid prolonged continuous high-speed rotation of the excavator in a single direction to reduce eccentric wear of the joint ring and seals. If hydraulic oil leaks at the rotary joint, or if the equipment moves weakly or slowly (possibly due to insufficient pressure caused by internal leakage), it should be repaired in a timely manner.