Relief Valve Damping Layout for Compact Piston Length
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Solution Overview
Problem
Existing relief valves are oversized due to the need for a communication hole that must be positioned behind the maximum lift position of the plunger, which elongates the piston and increases the valve size.
Innovation Solution
A relief valve design that includes a communication space between the plunger and piston, allowing the damping chamber to be positioned overlapping with the plunger, thereby reducing the length of the valve and enabling downsizing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the communication hole is positioned behind the maximum lift position of the plunger to ensure it is not covered, then the plunger sealing is maintained, but the piston becomes elongated backward resulting in an increase in the size of the relief valve
Solution Approach 1:
The patent introduces a communication space formed between the plunger and piston, allowing the damping chamber to be positioned in an overlapping manner rather than linearly behind the plunger. This spatial reconfiguration in a different dimension (radial/axial overlap vs. linear extension) enables the communication hole to be positioned without elongating the piston, thus resolving the contradiction between sealing reliability and compact size.
Solution Approach 2:
The communication space is formed within the overlapping region of the plunger and piston, effectively nesting the communication function within the existing structural overlap. This allows the damping chamber to access the communication hole through the nested configuration rather than requiring linear extension, maintaining sealing while reducing overall piston length.
2Ease of manufacture
If the damping chamber is positioned behind the plunger to avoid plunger coverage, then the communication hole positioning is simplified, but the relief valve size increases
Solution Approach 1:
Instead of positioning the damping chamber in the traditional linear direction behind the plunger, the patent utilizes the overlapping region between plunger and piston to create a compact three-dimensional arrangement. The communication space is formed in this overlapping zone, allowing oil flow communication without increasing the axial length or overall volume of the relief valve.
3Ease of operation
If the piston is formed elongated to position the communication hole behind the maximum lift position, then the plunger can reciprocate freely without covering the communication hole, but the length of the relief valve increases
Solution Approach 1:
The communication space is nested within the overlapping region of the plunger and piston, allowing the plunger to reciprocate within this confined space without covering the communication hole. This nested configuration enables free plunger movement while maintaining a compact overall length, as the communication function is integrated into the existing structural overlap rather than requiring additional linear space.
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
The design achieves downsizing of the relief valve while maintaining its pressure-relief function, allowing for efficient hydraulic pressure regulation and reduced surge pressure.
Implementation Method 1
a spring member that biases the plunger toward the closed position
Implementation Method 2
a damping chamber formed around an outer peripheral surface of the piston and configured to store the operating oil to restrict movement of the piston in a compression direction
Implementation Method 3
The plunger includes a first damping passage penetrating the plunger and bringing an area outside the plunger and the through passage into communication
Implementation Method 4
The piston includes a second damping passage penetrating the piston and bringing an area inside the piston and the damping chamber into communication
Implementation Method 5
by adjusting the flow rate of the operating oil to be discharged, it is possible to prevent the piston from instantly moving through its full stroke
Data Source
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AI summary
A relief valve includes: a housing; a plunger movable to each of a closed position and an open position; a differential pressure chamber; a spring member; a piston; and a damping chamber. The plunger includes a first damping passage penetrating the plunger and bringing an area outside the plunger and a through passage into communication. The piston includes a second damping passage penetrating the piston and bringing an area inside the piston and the damping chamber into communication. A communication space connected to each of the first damping passage and the second damping passage is formed between the plunger and the piston.