Hydraulic Buffer Elastic Rubber Section Cutout Design

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Solution Overview

Problem

Hydraulic shock absorbers face challenges in achieving good damping force properties, particularly in the dynamic spring and frictional regions, leading to inconsistent damping performance across varying piston speeds.

Innovation Solution

The hydraulic shock absorber incorporates an elastic rubber section with a cutout section that extends to a shallower portion than the deepest section in the axial direction, allowing for increased compressive force and smooth transition of damping force with piston speed, featuring a friction member with a base section and tube section configuration that enhances dynamic spring region and reduces dynamic frictional region.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the elastic rubber section is configured with a cutout section extending to a shallower portion than the deepest section, then the compressive force increases and damping force properties improve, but the structural complexity increases

Engineering Contradiction:
Improvedamping force propertiesVSAvoidstructural complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The elastic rubber section is divided into multiple functional zones including a cutout section, a deepest section, and an extending section. This segmentation allows each zone to perform specific functions: the cutout section increases compressive force, the deepest section provides structural support, and the extending section ensures smooth transition of damping force, thereby improving overall damping performance while managing structural complexity

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different portions of the elastic rubber section are given different geometric properties to optimize local performance. The cutout section has a shallower depth to increase compressive force in specific regions, while the extending section has a different geometry to ensure smooth transition. This local differentiation of properties allows the structure to achieve superior damping characteristics without requiring complete redesign of the entire component

Inventive Principle:
Principle #3Local quality

2Reliability

If the friction member configuration is optimized to enhance dynamic spring region, then damping force properties at low piston speeds improve, but the device complexity increases

Engineering Contradiction:
Improvedamping force properties at low piston speedsVSAvoidfriction member configuration complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The friction member is designed with dynamic characteristics through the elastic rubber section that can adapt its stiffness and damping properties based on operating conditions. The cutout section and extending section create a structure that dynamically adjusts the spring region characteristics, providing enhanced damping at low piston speeds while maintaining adaptability across different operating ranges

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The friction member combines elastic rubber material with a structured geometric configuration including cutout and extending sections. This composite approach integrates the material properties of elastic rubber with the geometric complexity of the cutout design, creating a friction member that provides enhanced dynamic spring characteristics without requiring separate mechanical spring components

Inventive Principle:
Principle #40Composite materials

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

This configuration results in improved damping force properties, particularly at low piston speeds and high frequencies, enhancing riding comfort and handling stability by smoothly connecting the dynamic spring force to hydraulic damping, reducing abrupt changes in damping force.

Implementation Method 1

the elastic rubber section (91) comes in sliding contact with the outer circumferential section of the piston rod (15)

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Implementation Method 2

a friction member (22) and an inner circumferential section of the friction member (22) comes in sliding contact with the outer circumferential section of the piston rod (15)

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP2878852B1Hydraulic buffer
Publication Date: 2020.03.18 HITACHI AUTOMOTIVE SYST LTD
  • EP2878852B1 patent drawingFigure 1
  • EP2878852B1 patent drawingFigure 2
  • EP2878852B1 patent drawingFigure 3

AI summary

In a friction member (22), a base section (92) is constituted by a bottom section (101) and a tube section (102). The bottom section (101) has a bored disk shape, and the tube section (102) has a cylindrical shape extending from an outer circumferential side of the bottom section (101) in the axial direction. An elastic rubber section (91) has a minimum inner diameter section (137), diameter expanding sections (138), (139) which are disposed at each side in the axial direction of the minimum inner diameter section (137). A tube section adhering surface (126) is installed at outer circumferential side of a tube section (102). A cutout section (151) is at least partially formed at a bottom section adhering surface (128) fixed to the bottom section (101) and the tube section (102) side of an open surface at an opposite side in the axial direction, and a deepest section (155) of the cutout section (151) is shallower than a position in the axial direction of the minimum inner diameter section (137).