Shock Absorber Piston Valve Segmentation for Damping Control

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Solution Overview

Problem

Conventional shock absorbers face challenges in maintaining appropriate damping force across a wide speed range, including extra slow speeds, while ensuring compatibility between attenuation characteristics at different speed ranges, often compromising durability.

Innovation Solution

A shock absorber design featuring a piston with a first leaf valve having free ends in both radial directions and a second leaf valve with one fixed end, arranged in series, allowing the first valve to generate damping force at extra slow speeds and the second valve to adjust damping force based on piston speed, ensuring compatibility across a wide range.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a leaf valve with low rigidity is employed to generate appropriate damping force in extra slow speed range, then the attenuation characteristic in extra slow speed range is improved, but the durability is reduced

Engineering Contradiction:
Improveattenuation characteristic in extra slow speed rangeVSAvoiddurability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The damping valve is divided into two separate valves: a first valve with a leaf valve having both edge portions as free ends for extra slow speed range, and a second valve with a leaf valve having one fixed end for ordinary speed range. This segmentation allows each valve to be optimized for its specific speed range, with the first valve providing low rigidity for extra slow speed damping while the second valve provides high rigidity for durability in ordinary conditions.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different structural qualities are applied to different valves based on their functional requirements. The first leaf valve has both edge portions as free ends to achieve low rigidity and flexibility for extra slow speed attenuation, while the second leaf valve has one fixed end to achieve high rigidity and durability for ordinary speed range operation.

Inventive Principle:
Principle #3Local quality

2Adaptability or versatility

If a single valve structure is used, then the device complexity is reduced, but the compatibility between attenuation characteristics in different speed ranges cannot be ensured

Engineering Contradiction:
Improvecompatibility between attenuation characteristicsVSAvoidvalve structure complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The damping valve is divided into two separate valves: a first valve with a leaf valve having both edge portions as free ends for extra slow speed range, and a second valve with a leaf valve having one fixed end for ordinary speed range. This segmentation allows each valve to be optimized for its specific speed range.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The damping valve assembly serves multiple functions across different speed ranges. The first valve handles extra slow speed attenuation while the second valve handles ordinary speed range attenuation, making the overall system universal for the complete speed spectrum from extra slow to high speeds.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Reliability

If a leaf valve with high rigidity is used to ensure durability, then the reliability is improved, but the attenuation characteristic in extra slow speed range deteriorates

Engineering Contradiction:
ImprovedurabilityVSAvoidattenuation characteristic in extra slow speed range
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The damping valve is divided into two separate valves: a first valve with a leaf valve having both edge portions as free ends for extra slow speed range, and a second valve with a leaf valve having one fixed end for ordinary speed range. This segmentation allows each valve to be optimized for its specific speed range.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different structural qualities are applied to different valves based on their functional requirements. The first leaf valve has both edge portions as free ends to achieve low rigidity and flexibility for extra slow speed attenuation, while the second leaf valve has one fixed end to achieve high rigidity and durability for ordinary speed range operation.

Inventive Principle:
Principle #3Local quality

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 effectively generates appropriate damping force across a wide speed range, including extra slow speeds, while maintaining the durability of the shock absorber by utilizing the unique opening and closing mechanisms of the leaf valves.

Implementation Method 1

a first valve that includes: a first leaf valve whose inner edge portion and outer edge portion in a radial direction of the piston are free ends; a first valve seat portion configured to support the inner edge portion of the first leaf valve from one side in an axial direction; a first oil passage, the first leaf valve opening and closing the first oil passage

Methodology Applied
Scientific EffectHydraulic damping: Viscous Damping

Implementation Method 2

a second valve that includes: a second leaf valve one of whose inner edge portion and outer edge portion in the radial direction is a fixed end; and a second oil passage, the second leaf valve opening and closing the second oil passage

Methodology Applied
Scientific EffectHydraulic damping: Viscous Damping

Data Source

PatentEP2894367B1Shock absorber
Publication Date: 2020.04.15 TOYOTA JIDOSHA KK
  • EP2894367B1 patent drawingFigure 1
  • EP2894367B1 patent drawingFigure 2
  • EP2894367B1 patent drawingFigure 3~4

AI summary

A shock absorber (100; 101; 102) includes a cylinder (7), a piston (1), and a piston rod (2). The piston includes a first valve (10) and a second valve (20). The first valve includes a first leaf valve (11), a first valve seat portion (5), a second valve seat portion (3b), and a first oil passage (31). The second valve includes a second leaf valve (21, 22) and a second oil passage (32). The first valve and the second valve are arranged in series.