4446002 Hitachi genuine overflow valve for Hitachi ZX240-3 excavators.

This relief valve (part no. 4446002) is the original main relief valve for Hitachi ZX200 excavators, compatible with the core circuit of its hydraulic system. With a pressure setting precisely matching the model’s operating conditions, it quickly relieves pressure when the system pressure exceeds the limit, preventing damage to core components such as the main pump and cylinders due to overload. It also has an oil-replenishing function to prevent cavitation, serving as a key pressure protection component for the safe and stable operation of the entire hydraulic system.

It adopts a forged alloy steel valve body, vacuum-quenched with a compressive strength of over 420MPa, paired with imported wear-resistant seals, enduring ultra-high pressure and high-flow impact. The internal pilot structure is precision-ground, with a relief response time ≤0.03 seconds and pressure fluctuation controlled within ±0.5MPa. It operates stably between -30°C and 80°C, adapting to extreme heavy-load operating environments such as mines, with no leakage or jamming during long-term use.

Following ZX200’s original installation standards, the threaded interface and seal groove are precisely matched, enabling quick replacement without additional processing. Installation can be completed within 15 minutes with special tools, significantly reducing downtime. Its precise relief control reduces hydraulic shock and component wear, extending the service life of core hydraulic parts such as the main pump, improving mining heavy-load operation efficiency and lowering equipment maintenance costs.