Shock Absorber Valve Chamfer Restriction for High-Frequency Stability

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Solution Overview

Problem

Existing shock absorber valve arrangements face challenges in maintaining stability and preventing pressure overshoots during high-frequency oscillations and large shock absorber accelerations, leading to poor high-frequency performance.

Innovation Solution

A valve arrangement featuring a chamfer restriction with a non-zero angle of 45° or less, which creates a pressure differential that stabilizes the valve member and allows for rapid response to changing fluid flows, replacing fixed restrictions and reducing pressure overshoots.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If a fixed restriction is incorporated upstream from the pilot chamber inlet to provide stabilizing effect, then stability is improved for low oscillation frequencies, but pressure overshoots occur at higher oscillation frequencies leading to poor high frequency performance

Engineering Contradiction:
ImprovestabilityVSAvoidhigh frequency performance
Core Design Contradiction:
Stability of the object's compositionVSReliability

Solution Approach 1:

The patent changes the geometric parameters of the restriction from a fixed cylindrical shape to a chamfered shape with specific angles (α and β). This parameter change allows the restriction to provide stable operation at low frequencies while preventing pressure overshoots at high frequencies, thus resolving the contradiction between stability and high frequency performance.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The chamfered restriction geometry creates different flow characteristics depending on the operating conditions. At low frequencies, the restriction provides stabilizing effect, while at high frequencies, the geometry prevents excessive pressure buildup, allowing the system to adapt dynamically to different oscillation frequencies.

Inventive Principle:
Principle #15Dynamics

2Speed

If the main valve arrangement opens rapidly to control pressure at higher oscillation frequencies, then pressure control is improved, but oil displacement through the fixed restriction generates increased flow leading to pressure overshoots

Engineering Contradiction:
Improvevalve opening speedVSAvoidpressure overshoot
Core Design Contradiction:
SpeedVSStress or pressure

Solution Approach 1:

By changing the restriction geometry to a chamfered shape with specific angles, the patent enables rapid valve opening at high frequencies while controlling the pressure differential across the restriction. This prevents the pressure overshoots that would otherwise occur with fixed cylindrical restrictions during rapid valve transitions.

Inventive Principle:
Principle #35Parameter changes

3Adaptability or versatility

If the opening force threshold is made adjustable by means of a force actuator, then adaptability is improved, but device complexity increases

Engineering Contradiction:
Improveadjustability of opening force thresholdVSAvoidcomplexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent incorporates a force actuator that can adjust the opening force threshold of the valve member. This allows the system to adapt to different operating conditions and frequency ranges by changing the force threshold parameter, providing versatility while keeping the adjustment mechanism relatively simple.

Inventive Principle:
Principle #35Parameter changes

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 chamfer restriction enhances stability and high-frequency performance by ensuring the valve arrangement responds effectively to increased damping fluid flows, reducing pressure overshoots and improving overall performance.

Implementation Method 1

The chamfer restriction provides a pressure drop of damping fluid pressure when damping fluid flows through the valve arrangement, thereby subjecting the valve member to a pressure differential contributing to a stabilizing pressure gradient for increasing damping fluid flows.

Methodology Applied
Scientific EffectPressure differential: Pressure Drop

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, wherein said damping fluid pressure force is provided by damping fluid pressure acting on an inlet side of the valve member

Methodology Applied
Scientific EffectPressure force: Pressure Increase

Data Source

PatentEP4459151A1A valve arrangement for improved high frequency performance, a shock absorber comprising the same, and a method for adjusting damping fluid flow
Publication Date: 2024.11.06 ADVANCED SUSPENSION TECHNOLOGY LLC
  • EP4459151A1 patent drawingFigure 1
  • EP4459151A1 patent drawingFigure 2a~2b
  • EP4459151A1 patent drawingFigure 3

AI summary

The present disclosure relates to a valve arrangement (1) for improved high frequency performance. The valve arrangement (1) comprises: a valve seat member (2) adapted in size and shape to define a valve seat (21) and a flow-through opening (20); a valve member (3) adapted to be displaceable relative the valve seat (21) along a displacement axis (A) during use in response to a damping fluid pressure force overcoming an opening force threshold, wherein said damping fluid pressure force is provided by damping fluid pressure acting on an inlet side of the valve member (3), said opening force threshold being at least partly adjustable by means of a force actuator (9), wherein the valve member (3) and the valve seat member (2) are adapted to provide a chamfer restriction (22, 32) provided with an opening crosssection which decreases from an inner lateral position to an outer lateral position relative the displacement axis (A). A shock absorber (1000A, 1000B) comprising said valve arrangement (1) and a method for adjusting damping fluid flow is disclosed also.