31Q8-17780 Main Relief Valve Pressure Relief Valve Safety Valve R210LC-9 R220LC

Product Specification

31Q8-17780 Main Relief Valve Pressure Relief Valve Safety Valve R210LC-9 R220LC-9S R290LC-9 R300LC-9S R330LC-9S Excavator Parts

Product Description

The GVO excavator relief valve, compatible with Hitachi excavators, is a key pressure control valve in the hydraulic system. It regulates hydraulic pressure, releases overload pressure, protects core hydraulic components such as the main valve and hydraulic pump, and ensures stable operation of the entire machine.

This relief valve is precision-machined from high-quality steel and undergoes overall quenching treatment. Equipped with oil-resistant and high-pressure-resistant seals, it boasts excellent sealing performance, impact resistance, and wear resistance. Suitable for the high-pressure hydraulic conditions of excavators, it effectively prevents internal leakage, pressure loss, operational instability, and vibration.

Product Introduction

This threaded cartridge-type main relief valve is a core pressure protection component of the hydraulic system in modern ninth-generation electronically controlled fuel injection excavators. It is perfectly compatible with five mainstream tonnage models: R210LC-9, R220LC-9S, R290LC-9, R300LC-9S, and R330LC-9S, covering medium-sized earthmoving equipment up to 33-ton heavy-duty mining equipment. It serves as the main control multi-way valve with built-in pressure control, and is also a key precision valve for pressure limiting and overload relief in the entire hydraulic circuit. It directly determines the machine's excavating power, smoothness of operation, and the service life of core components such as hydraulic pumps, cylinders, and motors.

The entire overflow valve core assembly uses high-quality alloy structural steel solid bars as the base material, and is precision-machined on a high-precision CNC lathe throughout the process. The cylindrical surface undergoes double precision machining, including centerless grinding and external mirror grinding. The coaxiality and roundness tolerances of the valve core are controlled at the micron level. After installation into the valve block, the gap is uniform, ensuring smooth reciprocating opening and closing without jamming or uneven wear, effectively preventing impurities from causing valve jamming.

Internal core, valve seat, pressure regulating spring, throttling damping plate, and other core load-bearing components undergo a unified carburizing and quenching + low-temperature stress-relieving tempering dual heat treatment process. This significantly improves surface hardness, enabling it to withstand long-term high-speed erosion by high-pressure hydraulic oil and abrasive wear from tiny hard particles in the oil. This fundamentally eliminates common industry malfunctions such as valve core sealing surface scoring, excessive internal leakage, and inability to lock pressure. The intermediate connection thread is a metric precision full thread with high pitch accuracy and tight engagement, making it less prone to loosening and pressure loss under long-term equipment vibration. The tail pressure adjusting nut is equipped with an anti-loosening locking structure, which can be locked for a long time after the system pressure is calibrated, and will not cause pressure drift or decline due to continuous vibration.

Packaging & Shipping

We use high-strength, environmentally friendly paper export packaging, which is reinforced, cushioned, and moisture-proof, suitable for long-distance international logistics transportation, and meets cross-border freight and environmental protection standards. International transportation adopts formal cross-border logistics, with full tracking of logistics information and supporting customs clearance documents to ensure smooth customs clearance and timely delivery of goods overseas.

Company Introduction

The GVO brand is a manufacturer of hydraulic components. We mainly produce the most comprehensive range of pilot pumps, gear pumps, relief valves, hydraulic pumps, electrical components, hydraulic parts, engine assemblies, traveling assemblies, rotating assemblies, distribution valves, and other components.

We are factory direct sellers without any middlemen profiting from price differences. The quality is definitely the best for you because we are the ones who produce them. We cannot tarnish our reputation. The prices are also the most favorable for you. There is a stable delivery speed.

We value every customer and provide you with the best service. We offer pre-sale, in-sale, and after-sale guarantees. Any problems will definitely be resolved for you. We are always available to serve you.