Relief Valve Piston Layout for Low Pilot Pressure Adjustment
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Solution Overview
Problem
Existing relief valves require a high pilot pressure to adjust relief pressure due to the force exerted by pressure fluid in the control chamber, making it difficult to adjust relief pressure while reducing pilot pressure.
Innovation Solution
The relief valve design includes a housing with a pilot chamber and an oil chamber, a valve body, an urging member, and a piston with pressure receiving surfaces that oppose forces in both axial directions, reducing the force against the pilot pressure and allowing for adjustment of relief pressure with lower pilot pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the pressure fluid is guided into the control chamber, then the relief valve can adjust the relief pressure, but a high pilot pressure is required to push back the force due to the pressure of the pressure fluid
Solution Approach 1:
The invention introduces a counterbalancing force mechanism where a counterbalancing spring acts on the piston in the same direction as the pilot pressure. This counterbalancing spring force opposes the force due to pressure fluid in the control chamber, allowing the pilot pressure to only need to overcome the difference between these two forces rather than the full force, thereby reducing the required pilot pressure while maintaining relief pressure adjustment capability
Solution Approach 2:
The invention introduces a counterbalancing spring as an intermediary element between the pressure fluid force and the pilot pressure. This spring mediates the force balance by providing a counteracting force that reduces the net force the pilot pressure must overcome, enabling more efficient force transmission and lower pilot pressure requirements
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design enables adjustment of relief pressure while reducing the required pilot pressure, improving the accuracy and efficiency of pressure adjustment, even with varying back pressures.
Implementation Method 1
a first pressure receiving surface to receive a pressure in a first axial direction of an axial direction from the hydraulic oil in the first oil chamber, and a second pressure receiving surface to receive a pressure in a second axial direction of the axial direction from the hydraulic oil in the second oil chamber
Implementation Method 2
press the urging member using a pressure of pilot oil in the pilot chamber to change an amount of deflection of the urging member
Data Source
AI summary
A relief valve includes a piston including a first piston member to press an urging member using a pressure of pilot oil in a pilot chamber to change an amount of deflection of the urging member. The first piston member includes a first pressure receiving surface to receive a pressure in a first axial direction of an axial direction from hydraulic oil in a first oil chamber, and a second pressure receiving surface to receive a pressure in a second axial direction of the axial direction from the hydraulic oil in a second oil chamber.