Direct-Acting Pressure Relief Valve for Stable Vibration Damping

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Solution Overview

Problem

Existing vibration dampers with pilot-operated pressure relief valves experience force overshoot and oscillation, leading to fluctuations in damping force due to their complex design and the use of check valves, which are sensitive to geometric component tolerances.

Innovation Solution

A vibration damper with a direct-acting pressure relief valve using a main piston that is actuated by a force actuator in both directions, eliminating the need for pilot-operated valves and check valves, and incorporating adjustable opening forces through geometric adjustments to manage dimensional deviations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a pilot-operated pressure relief valve is used, then the pressure relief function is achieved, but force overshoot and oscillation occur leading to unstable damping force

Engineering Contradiction:
Improvepressure relief functionVSAvoiddamping force stability
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent extracts and eliminates the pilot-operated valve mechanism from the pressure relief system. Instead of using a complex pilot valve with pre-stage and main-stage components, the invention employs a simple direct-acting pressure relief valve with a single valve body and valve disc that responds directly to pressure differential forces, thereby eliminating force overshoot and oscillation while maintaining reliable pressure relief functionality.

Inventive Principle:
Principle #2Taking out (Extraction)

2Ease of operation

If check valves are used in the pressure relief valve, then fluid flow direction control is achieved, but the damping force becomes sensitive to geometric component tolerances

Engineering Contradiction:
Improvefluid flow direction controlVSAvoidgeometric component tolerances sensitivity
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The patent introduces a specially designed valve disc that acts as an intermediary element to control fluid flow direction without requiring check valves. The valve disc incorporates flow direction control functionality through its geometric design and positioning mechanism, eliminating the need for separate check valve components and reducing sensitivity to manufacturing tolerances.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If a complex pressure relief valve design with multiple valves is used, then comprehensive pressure relief functionality is achieved, but the device complexity increases

Engineering Contradiction:
Improvepressure relief functionalityVSAvoidvalve assembly complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges multiple valve functions into a single integrated pressure relief valve assembly. The design combines the pressure relief valve body, valve disc, spring mechanism, and flow direction control elements into one unified structure, eliminating the need for separate pilot valves, check valves, and associated components, thereby significantly reducing device complexity while maintaining comprehensive pressure relief functionality.

Inventive Principle:
Principle #5Merging (Combining)

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 provides stable damping force without oscillation, reduces complexity, and minimizes the influence of geometric component tolerances, ensuring consistent performance in both compression and rebound stages.

Implementation Method 1

the pressure relief valve is equipped with a first opening force means which is configured to exert an opening force on the main piston in the first actuation direction of the piston

Methodology Applied
Scientific EffectForce: Force

Implementation Method 2

the pressure relief valve is equipped with a second opening force means which is configured to exert an opening force on the main piston in the second actuation direction of the piston

Methodology Applied
Scientific EffectForce: Force

Implementation Method 3

fluid flows from the first working chamber into the second working chamber

Methodology Applied
Scientific EffectFluid flow:

Implementation Method 4

fluid flows from the second working chamber into the first working chamber

Methodology Applied
Scientific EffectFluid flow:

Data Source

PatentEP4488543B1Vibration damper, and method for operating a pressure limiting valve in a vibration damper
Publication Date: 2026.02.25 THYSSENKRUPP BILSTEIN GMBH
  • EP4488543B1 patent drawingFigure 1
  • EP4488543B1 patent drawingFigure 2
  • EP4488543B1 patent drawingFigure 3

AI summary

The present invention relates to an adjustable vibration damper, in particular for a vehicle chassis, comprising a fluid-filled cylinder tube (10) with a piston (2) which is axially movable within the cylinder tube (10) in a first actuation direction (R1) and an opposite second actuation direction (R2) and which divides the cylinder tube (10) into a first working chamber (11) and a second working chamber (21), wherein a pressure relief valve through which the fluid flows is provided for damping the piston movement, wherein the pressure relief valve (100) comprises a main piston (1001) slidably received in a main piston chamber (1002) for opening or closing the pressure relief valve (100), wherein the pressure relief valve (100) is equipped with a first opening force means which is configured to exert an opening force on the main piston (1001) in the first actuation direction of the piston (2).wherein the pressure relief valve (100) is equipped with a second opening force means which is configured to exert an opening force on the main piston (1001) in the second actuation direction of the piston, wherein the second opening force means comprises an auxiliary piston (1009) slidably received in the main piston (1001), and a method for operating a pressure relief valve in a vibration damper according to the invention.