Shock Absorber Valve Chamfer Restriction for High-Frequency Stability
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Solution Overview
Problem
Existing shock absorber valve arrangements face challenges in high frequency performance due to slow response times, leading to undesired damping effects such as oscillations and pressure overshoots, especially during high oscillation frequencies and shock absorber accelerations.
Innovation Solution
A valve arrangement with a chamfer restriction that provides a pressure drop through a decreasing opening cross-section, allowing the valve to respond rapidly to changing damping fluid flows, featuring a non-zero chamfer restriction angle of 45° or less, which stabilizes the valve and reduces pressure overshoots.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a fixed restriction is incorporated upstream from a pilot chamber inlet to provide stabilizing effect, then stability is improved for low oscillation frequencies, but pressure overshoots occur at higher oscillation frequencies causing poor high frequency performance
Solution Approach 1:
The invention changes the geometric parameters of the restriction by providing a chamfered surface with a specific chamfer angle (5-45 degrees) instead of a simple fixed restriction. This parameter change allows the restriction to provide stabilizing effect at low frequencies while preventing pressure overshoots at high frequencies, thereby resolving the contradiction between stability and high frequency performance
Solution Approach 2:
The invention adds a dimensional aspect to the restriction by creating a chamfered surface that extends radially outward from the displacement axis. This three-dimensional chamfer structure (with radial, axial, and circumferential dimensions) allows the restriction to function differently at various frequencies, providing stability when needed and preventing overshoots at high frequencies
2Speed
If the main valve arrangement opens rapidly to control pressure at higher oscillation frequencies, then response speed is improved, but oil displacement through the fixed restriction generates increased flow causing pressure overshoots
Solution Approach 1:
By changing the geometric parameters of the restriction to include a chamfered surface with controlled angle and dimensions, the invention allows rapid valve opening for improved response speed while the chamfer geometry controls the oil displacement flow to prevent pressure overshoots, thus resolving the contradiction between response speed and pressure control
3Productivity
If a chamfer restriction with decreasing opening cross-section is provided, then rapid response to changing damping fluid flows is achieved, but manufacturing complexity increases
Solution Approach 1:
The invention defines specific parameter ranges for the chamfer angle (5-45 degrees) and the chamfer dimensions to achieve the desired decreasing opening cross-section. By specifying these parameters within certain ranges, the invention ensures rapid response performance while keeping the manufacturing process within reasonable complexity limits that can be achieved through standard machining operations
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 valve arrangement improves stability and high frequency performance by ensuring the valve responds effectively to increased damping fluid flows, reducing pressure overshoots and maintaining stability during high frequency operations.
Implementation Method 1
The chamfer restriction provides a pressure drop of damping fluid pressure when damping fluid flows through the valve arrangement
Implementation Method 2
a valve member adapted to be displaceable relative the valve seat along a displacement axis during use in response to a damping fluid pressure force overcoming an opening force threshold
Data Source
AI summary
A valve arrangement for improved high frequency performance comprises: a valve seat member adapted in size and shape to define a valve seat and a flow-through opening; a valve member adapted to be displaceable relative the valve seat along a displacement axis during use in response to a damping fluid pressure force overcoming an opening force threshold, wherein the damping fluid pressure force is provided by damping fluid pressure acting on an inlet side of the valve member, the opening force threshold being at least partly adjustable by a force actuator, wherein the valve member and the valve seat member are adapted to provide a chamfer restriction provided with an opening cross-section which decreases from an inner lateral position to an outer lateral position relative the displacement axis. A shock absorber comprising the valve arrangement and a method for adjusting damping fluid flow are disclosed.