Hydraulic Compression Stop Member with Pressure Relief Valve
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Solution Overview
Problem
Existing hydraulic compression stop members for twin-tube hydraulic shock-absorbers in vehicle suspensions fail to effectively limit maximum pressure in the working chamber, leading to potential structural integrity issues due to pressure increases as the rod speed increases.
Innovation Solution
A hydraulic stop member with a bypass conduit and pressure relief valve that connects the working chamber to the compression chamber above the seal ring, keeping the bypass conduit closed until pressure exceeds a threshold, allowing oil discharge through the pressure relief valve to maintain constant pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the rod speed increases, then the damping performance improves, but the pressure in the working chamber increases excessively
Solution Approach 1:
A bypass conduit is introduced as an intermediary pathway that connects the working chamber to the compression chamber. This bypass conduit includes a pressure relief valve that remains closed during normal operation but opens when pressure exceeds a threshold value, providing an alternative route for damping fluid to flow from the working chamber to the compression chamber, thereby preventing excessive pressure buildup while maintaining damping performance
Solution Approach 2:
The system dynamically changes the flow parameters of the damping fluid by introducing a pressure-dependent bypass pathway. When pressure in the working chamber exceeds a predetermined threshold, the pressure relief valve opens, changing the flow path and allowing fluid to bypass through the bypass conduit to the compression chamber, thus controlling pressure while maintaining operational speed
2Ease of manufacture
If passages are provided in the bottom wall of the cup-shaped body, then the structure is simple, but the pressure cannot be effectively limited
Solution Approach 1:
Instead of using simple open passages in the bottom wall, a bypass conduit with a pressure relief valve is introduced as an intermediary controlled pathway. This valve acts as a mediator that selectively opens only when pressure exceeds the threshold, providing effective pressure limitation while maintaining structural integrity and controlled fluid flow
Solution Approach 2:
The bypass conduit system transitions from a static simple passage to a dynamic controlled pathway. The pressure relief valve dynamically opens and closes based on pressure conditions, allowing the system to adapt its flow characteristics to maintain pressure within acceptable limits while preserving the relatively simple cup-shaped body structure
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 solution effectively limits the maximum pressure in the working chamber to a predetermined value, preventing excessive pressure buildup and ensuring structural integrity by allowing controlled oil discharge when pressure exceeds the threshold.
Implementation Method 1
A pressure relief valve is provided in the bypass conduit which acts to keep the bypass conduit closed as long as the pressure in the working chamber remains below a predetermined threshold value and to open the bypass conduit, thereby allowing discharge of oil from the working chamber to the compression chamber through this conduit, when the pressure in the working chamber exceeds this threshold value
Implementation Method 2
The closure member is spring-loaded towards the valve seat, wherein the spring is arranged between the closure member and the piston of the stop member
Data Source
AI summary
The hydraulic stop member comprises: a cup-shaped body mounted in a compression chamber of the shock-absorber. A piston is mounted at an end of a rod of the shock-absorber so as to slide in the cup-shaped body when the shock-absorber is close to an end-of-travel position of the compression stroke. The cup-shaped body includes a side wall and a bottom wall which define, along with the piston, a working chamber where a damping fluid of the shock-absorber is compressed by the piston. A bypass conduit connects a working chamber with the portion of the compression chamber placed above a seal ring. A pressure relief valve keeps the bypass conduit closed as long as the pressure in the working chamber remains below a given threshold value and to open the bypass conduit, thereby allowing the discharge of the damping fluid from the working chamber to the compression chamber through the bypass conduit, when the pressure in the working chamber exceeds the threshold value.