Work machine
CN116981851BActive Publication Date: 2026-07-07HITACHI CONSTRUCTION MACHINERY CO LTD
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- HITACHI CONSTRUCTION MACHINERY CO LTD
- Filing Date
- 2021-03-18
- Publication Date
- 2026-07-07
AI Technical Summary
Technical Problem
In machinery equipped with pilot-operated relief valves, the pilot primary pressure cannot be stably generated when not in operation, resulting in poor energy consumption efficiency.
Method used
A pilot-driven relief valve is adopted, which combines a slide valve and a throttling section. The opening area of the throttling section is adjusted by controlling the axial movement of the slide valve to ensure stable generation of pilot primary pressure when not in operation.
Benefits of technology
When the actuator is not in operation, the pressure in the main circuit can be reliably maintained, thus improving energy consumption efficiency.
✦ Generated by Eureka AI based on patent content.
Smart Images
Figure CN116981851B_ABST
Abstract
A work machine is provided with a main circuit that supplies working fluid from a pump to an actuator, a pilot circuit that guides a part of the working fluid from the pump to a pilot pressure-receiving portion of a control valve, and a relief passage that connects the pump and an oil tank. A first pressure-reducing valve that generates a pilot primary pressure and second and third pressure-reducing valves that generate a pilot secondary pressure to the control valve and a relief valve are provided in the pilot circuit. A spool of the relief valve has a first movement region in which an opening area of a throttle portion changes in stages and a second movement region in which the opening area of the throttle portion continuously changes. A control device controls the third pressure-reducing valve so that the spool is positioned in the first movement region at a time of non-operation of the actuator and in the second movement region at a time of operation of the actuator. The throttle portion of the relief valve has a throttle hole that gives resistance to the passing working fluid when the spool is positioned in the first movement region.
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