Gas Spring End Member Assembly for Twist Isolation

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Solution Overview

Problem

Existing gas spring and damper assemblies in vehicle suspension systems face issues with relative rotation-induced twisting, leading to performance degradation, and known solutions often increase manufacturing complexity and costs.

Innovation Solution

The design incorporates an end member assembly with a torsional isolator supported on the damper housing, featuring a compliant body between rigid bodies to isolate rotational displacement and reduce lateral movement, using a combination of elastomeric and rigid components for a fixed rotational position.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the lower end member is rotatably supported on the damper housing using a friction-reducing bearing, then relative rotation-induced twisting is reduced, but lateral movement of the end member relative to the damper housing occurs

Engineering Contradiction:
Improvetwisting preventionVSAvoidlateral movement control
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

A seal member is introduced as an intermediary component between the end member and damper housing. This seal member simultaneously reduces friction to prevent twisting while maintaining positional stability to prevent lateral movement, resolving the contradiction between rotational freedom and lateral constraint

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The seal member is constructed from composite materials or a composite structure combining friction-reducing properties with lateral constraint capabilities, enabling it to perform both functions of preventing twisting and controlling lateral movement

Inventive Principle:
Principle #40Composite materials

2Stability of the object's composition

If attempts are made to minimize lateral movements of the end member, then lateral stability is improved, but manufacturing complexity and assembly time increase

Engineering Contradiction:
Improvelateral movement controlVSAvoidend member construction
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The seal member is designed to perform multiple functions simultaneously: sealing, friction reduction, and lateral movement control. This multi-functionality eliminates the need for separate components for each function, thereby reducing manufacturing complexity and assembly time while maintaining lateral stability

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

3Reliability

If relative rotation is permitted between the end member and damper housing, then twisting of the flexible wall is reduced, but lateral movement control becomes difficult

Engineering Contradiction:
Improvetwisting preventionVSAvoidlateral movement control
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The seal member acts as a mediator that enables rotational movement to prevent twisting while simultaneously constraining lateral movement through its geometric design and interaction with the damper housing, making the system easy to operate without compromising control

Inventive Principle:
Principle #24Intermediary (Mediator)

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 solution effectively reduces relative rotation-induced stress on the flexible spring member, enhancing the durability and performance of gas spring and damper assemblies while simplifying manufacturing and reducing assembly time and costs.

Implementation Method 1

a torsional isolator supported on the damper housing and including a compliant body disposed between the rigid bodies and operative to isolate rotational displacement

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

the configuration of the bearing element that supports the lower end member on the damper housing and the corresponding sealing arrangement can, in some cases, permit lateral movement of the second end member relative to the damper housing

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP4084978B1Gas spring and damper assemblies as well as suspension systems including same
Publication Date: 2023.11.15 FIRESTONE INDUSTRIAL PRODUCTS COMPANY LLC
  • EP4084978B1 patent drawingFigure 1
  • EP4084978B1 patent drawingFigure 2
  • EP4084978B1 patent drawingFigure 3

AI summary

End members (604) are supportable along a damper housing (200) and dimensioned for securement to flexible spring member (300). End members (604) include a wall (616) with a side wall portion (628) including an inner side surface portion (662). First projections (664) extend toward a first inner edge (668) with a first shoulder surface portion (666) faces a second end (612). Second projections (670) extend inward beyond the inner side surface portion (662) toward a second inner edge (674) with a second shoulder surface portion (672) facing a first end (610). Second projections (670) are spaced axially from first projections (664) such that a groove (676) is formed inward of the inner side surface portion (662) between first and second shoulder surface portions (666,668). End member assemblies (600) including such an end member (604) as well as gas spring and damper assemblies (AS1) and suspension systems (100) are also included.