Hydraulic Breaker Directional Control Valve SB81 Internal Valve for Excavator Rock Hammer

Product Introduction

This high-precision hydraulic breaker directional control valve is a core original hydraulic accessory specially designed for SB81 internal valve assembly, serving as a key control component for excavator rock hammer normal operation. As a professional built-in hydraulic valve spare part, it perfectly matches all standard SB81 hydraulic rock breakers, acting as the core switch to control hydraulic oil circuit direction, striking frequency and impact force stability. This SB81 breaker control valve adopts industrial-grade precision manufacturing technology, effectively solving common faults of old valves such as oil circuit blockage, slow response, irregular striking and hammer jamming. It perfectly adapts to medium and large excavator SB81 hammer construction conditions, maintains stable hydraulic circulation output, improves overall breaking efficiency, and greatly reduces equipment failure rate and daily maintenance costs for engineering machinery.

Core Functions

• Hydraulic Direction Control: Reciprocating spool switches high-pressure oil direction, feeds oil alternately to piston upper & lower chamber to drive continuous impact of breaker.
• Pressure & Frequency Regulation: Stabilize working pressure 160–180bar, control impact frequency 350–520BPM for 120–150L/min pump flow, solve no-load hitting & weak striking problems.
• Built-in Structure Advantage: No external hoses reduces oil leakage points, anti-knock & anti-abrasion, durable for harsh mining and demolition sites.

Product Working Principle

The built-in reversing valve for 140 hydraulic breaker is integrally installed inside the middle cylinder of the breaker, serving as the core automatic control component to realize reciprocating impact of the breaker piston. Powered by high-pressure hydraulic oil supplied from the excavator main pump, the internal spool slides automatically inside the valve sleeve under differential hydraulic force. It periodically switches the oil inlet and return passages, alternately delivering high-pressure oil to the upper and lower chambers of the impact piston. The pressure difference between piston chambers generates reciprocating driving force to push the piston to strike the chisel at high frequency for continuous breaking operation. The whole reversing process requires no external electric control or mechanical shifting fork; the automatic direction change is completely driven by hydraulic pressure difference, forming a fully hydraulic self-controlled oil distribution structure.