Damping Valve Retainer Flow Passage Area Design

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Solution Overview

Problem

Existing damping valves for shock absorbers face challenges in increasing the damping coefficient of the port characteristic when using a piston with a large flow passage area, making it difficult to achieve desired damping force characteristics, especially when used singly without a retainer.

Innovation Solution

A damping valve design that includes a valve disk partitioning the cylinder into chambers, a retainer with a flow passage area not smaller than the valve disk through hole, and annular leaf valves to manage fluid flow and resistance, allowing for adjustable damping force characteristics by varying the flow passage areas.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If a piston with a large flow passage area is used to avoid throttling working fluid, then the damping coefficient of port characteristic cannot be increased, making it difficult to achieve desired damping force characteristics

Engineering Contradiction:
Improveflow passage areaVSAvoiddamping coefficient
Core Design Contradiction:
Quantity of substanceVSProductivity

Solution Approach 1:

The invention divides the flow passage into multiple segments: the valve disk through hole, the retainer through hole, and the flow passage between them. By segmenting the flow path, the system can have a large overall flow passage area while maintaining localized flow restriction points that generate the desired port characteristic damping coefficient.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The retainer is introduced as an intermediary component between the valve disk and the leaf valve. The retainer with its through hole creates an additional flow passage stage that allows the working fluid to pass through multiple openings, enabling both large total flow area and sufficient flow resistance for port characteristic.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Quantity of substance

If the flow passage area of the retainer through hole is made large to avoid throttling, then the damping force characteristic cannot be adjusted, but making it small throttles the working fluid excessively

Engineering Contradiction:
Improveflow passage areaVSAvoiddamping force characteristic adjustability
Core Design Contradiction:
Quantity of substanceVSAdaptability or versatility

Solution Approach 1:

The invention enables parameter adjustment by changing the flow passage area of the retainer through hole. By modifying this specific parameter, the damping force characteristic can be adjusted without excessively throttling the working fluid, as the overall flow passage area remains large due to the multiple passage stages.

Inventive Principle:
Principle #35Parameter changes

3Device complexity

If a single piston is used without a retainer, then the number of components is reduced, but the damping coefficient of port characteristic cannot be increased

Engineering Contradiction:
Improvenumber of componentsVSAvoiddamping coefficient
Core Design Contradiction:
Device complexityVSProductivity

Solution Approach 1:

The retainer is nested on the piston, creating a compact multi-stage flow passage structure. This nesting arrangement allows the addition of flow passage control functionality without significantly increasing the overall component count or device complexity, while achieving the desired increase in damping coefficient.

Inventive Principle:
Principle #7Nested doll (Nesting)

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

Enables increased damping coefficient and adjustable damping force characteristics, allowing for various damping profiles without throttling the working fluid, even when using the piston singly, and allows for a smaller number of components to achieve multiple damping force characteristics.

Implementation Method 1

generates a damping force with a port characteristic due to resistance produced during the passage of the working fluid in the inner peripheral side flow passage when the leaf valve is opened to a certain extent

Methodology Applied
Scientific EffectFluid resistance: Drag

Implementation Method 2

the shock absorber generates a damping force due to the resistance of the damping force generating element

Methodology Applied
Scientific EffectFluid resistance: Drag

Data Source

PatentEP2801733B1Damping valve for shock absorber
Publication Date: 2017.05.17 KYB CORP
  • EP2801733B1 patent drawingFigure 1
  • EP2801733B1 patent drawingFigure 2A
  • EP2801733B1 patent drawingFigure 2B

AI summary

A damping valve includes a valve disk, a retainer, an inner peripheral side flow passage configured to include a valve disk through hole formed in an inner peripheral side of the valve disk and a retainer through hole formed in the retainer and allowing communication between one and other chambers, an outer peripheral side flow passage formed in an outer peripheral side of the valve disk and allowing communication between the one and the other chambers, and a leaf valve in the form of an annular plate arranged on a side of the retainer opposite to the valve disk and configured to openably close the inner peripheral side flow passage by an outer peripheral part. A flow passage area of the retainer through hole is not smaller than that of the valve disk through hole.