Shock Absorber Damping Valve With Variable Leaf Valve Gap

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Solution Overview

Problem

Conventional shock absorbers face limitations in adjusting damping force at low piston speeds, leading to reduced riding comfort and limited damping force adjustment width, as they rely on fixed orifices which restrict the range of damping force variation.

Innovation Solution

A damping valve with a leaf valve and variable biasing mechanism that adjusts the gap between the leaf valve and valve seat, allowing for increased flow area and reduced damping force at low speeds, while maintaining adjustable damping characteristics through the solenoid pressure control valve.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If the opening area of the fixed orifice is increased to decrease damping force at low piston speeds, then the damping force can be reliably decreased, but the maximum value of the damping force is determined by the fixed orifice and the damping force adjustment width is remarkably reduced

Engineering Contradiction:
Improvedamping forceVSAvoiddamping force adjustment width
Core Design Contradiction:
ForceVSAdaptability or versatility

Solution Approach 1:

The patent applies the dynamics principle by replacing the fixed orifice with a variable orifice formed by the gap between the leaf valve and valve seat. This gap can dynamically change its opening area based on the biasing force applied to the leaf valve, allowing the damping force to be adjusted across a wide range from low to high values. The orifice area is no longer fixed but becomes a controllable parameter that adapts to different operating conditions.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent implements parameter changes by varying the biasing force applied to the leaf valve through the biasing part. By changing this biasing force parameter, the opening area of the orifice (gap between leaf valve and valve seat) is directly modified, which in turn changes the damping force. This allows continuous adjustment of damping force from low to high values, expanding the adjustment width.

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If the disc valve is not provided with an orifice to increase damping force adjustment width, then the damping force adjustment width increases, but even if the damping force characteristics are set to full soft, the damping force may increase too much and this may worsen the riding comfort

Engineering Contradiction:
Improvedamping force adjustment widthVSAvoiddamping force
Core Design Contradiction:
Adaptability or versatilityVSForce

Solution Approach 1:

The patent controls the damping force parameter by adjusting the biasing force on the leaf valve. By precisely controlling this biasing force, the opening area of the orifice is optimized to achieve the desired damping force characteristics. This ensures that even in the softest damping mode, the damping force remains within acceptable limits for riding comfort while maintaining a wide adjustment range.

Inventive Principle:
Principle #35Parameter changes

3Device complexity

If a fixed orifice is used to control damping force, then the structure is simple, but the damping force adjustment width is limited and riding comfort is reduced at low piston speeds

Engineering Contradiction:
Improvevalve structureVSAvoiddamping force adjustment width
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent transitions from a static fixed orifice structure to a dynamic variable orifice structure using a leaf valve that can move relative to the valve seat. This dynamic structure allows the orifice area to change continuously, providing wide damping force adjustment capability while maintaining relatively simple valve construction.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The leaf valve structure enables the valve to self-regulate the orifice opening area in response to changes in biasing force. The variable gap between the leaf valve and valve seat automatically adjusts the damping characteristics based on the applied biasing force, eliminating the need for complex external control mechanisms while achieving wide adjustment range.

Inventive Principle:
Principle #25Self-service

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 decreases damping force at low piston speeds and expands the damping force adjustment range, enhancing vehicle riding comfort and damping control by varying the leaf valve's position relative to the valve seat.

Implementation Method 1

a biasing part configured to exert a variable biasing force on the leaf valve toward the valve disc

Methodology Applied
Scientific EffectElastic force: Elasticity

Implementation Method 2

a solenoid pressure control valve that controls the pressure within the back pressure chamber. A solenoid is used in the solenoid pressure control valve

Methodology Applied
Scientific EffectElectromagnetic force: Electromagnet

Implementation Method 3

a gap is provided between the leaf valve and the valve seat

Methodology Applied
Scientific EffectFluid flow through gap: Pressure Gradient

Data Source

PatentEP3225874B1Attenuation valve and shock absorber
Publication Date: 2023.08.23 KYB CORP
  • EP3225874B1 patent drawingFigure 1
  • EP3225874B1 patent drawingFigure 2
  • EP3225874B1 patent drawingFigure 3

AI summary

A damping valve includes a valve disc (2) including a passage (3, 4) and a valve seat (2d, 2c) configured to surround an outlet end of the passage (3, 4), a leaf valve (Ve, Vp) configured to separate from/sit on the valve seat (2d, 2c) to open/close the passage, and a biasing part configured to exert a variable biasing force on the leaf valve (Ve, Vp) toward the valve disc (2), and a gap is provided between the leaf valve (Ve, Vp) and the valve seat (2d, 2c).