Gas Spring End Member Assembly With Torsional Isolator

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Solution Overview

Problem

Existing gas spring and damper assemblies in vehicle suspension systems face issues with relative rotation-induced twisting of flexible walls, leading to performance degradation, and known solutions often compromise manufacturability, assembly time, and cost.

Innovation Solution

The use of a torsional isolator supported on a damper assembly with a compliant body between rigid bodies, forming a substantially-fixed rotational position to isolate rotational displacement from the flexible spring member, combined with end member assemblies that secure the gas spring and damper components in a manner that minimizes lateral movement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

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

Engineering Contradiction:
Improverotation-induced twistingVSAvoidlateral movement stability
Core Design Contradiction:
Object-affected harmful factorsVSStability of the object's composition

Solution Approach 1:

A torsional isolator is introduced as an intermediary component between the end member and damper housing. This isolator comprises a compliant body that permits rotational movement while restraining lateral movement, thereby mediating between the need for rotation and the need for lateral stability

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The compliant body's material properties are designed to exhibit different resistance characteristics for different types of movement: high compliance for rotation and high stiffness for lateral movement. This parameter differentiation allows the same component to address both requirements

Inventive Principle:
Principle #35Parameter changes

2Stability of the object's composition

If attempts are made to minimize lateral movement of the end member, then lateral movement stability improves, but manufacturability decreases and assembly time increases

Engineering Contradiction:
Improvelateral movement stabilityVSAvoidmanufacturability
Core Design Contradiction:
Stability of the object's compositionVSEase of manufacture

Solution Approach 1:

The torsional isolator employs a compliant body constructed from flexible material that can be molded as a single piece. This flexible structure achieves lateral movement restraint through its material properties rather than complex mechanical constraints, simplifying manufacturing

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The compliant body is made from composite material exhibiting both compliance and stiffness characteristics. This material approach allows a single-component design that is easier to manufacture than multi-component mechanical solutions while achieving both rotational freedom and lateral stability

Inventive Principle:
Principle #40Composite materials

3Object-affected harmful factors

If known designs are used to address rotation, then rotational issues are partially mitigated, but assembly complexity and cost increase

Engineering Contradiction:
Improverotation-induced twistingVSAvoidassembly complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The torsional isolator merges multiple functions into a single component: it provides rotational freedom, restrains lateral movement, and maintains axial positioning. This consolidation eliminates the need for separate bearing elements and sealing arrangements, reducing assembly complexity

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The compliant body serves multiple functions simultaneously: it acts as a rotational joint, a lateral movement constraint, and a sealing surface. This multi-functionality reduces the total number of components and simplifies the overall assembly

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

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 effectively reduces the adverse effects of relative rotation on the gas spring, enhancing the performance and manufacturability of gas spring and damper assemblies while maintaining assembly efficiency and reducing costs.

Implementation Method 1

a torsional isolator (700) supported on the damper assembly with a compliant body (702) between rigid bodies (704, 706), forming a substantially-fixed rotational position to isolate rotational displacement from the flexible spring member

Methodology Applied
Scientific EffectCompliance isolation: Elasticity

Data Source

PatentEP4084976B1End members and end member assemblies for gas spring and damper assemblies as well as gas spring and damper assemblies including same
Publication Date: 2023.10.04 FIRESTONE INDUSTRIAL PRODUCTS COMPANY LLC
  • EP4084976B1 patent drawingFigure 1
  • EP4084976B1 patent drawingFigure 2
  • EP4084976B1 patent drawingFigure 3

AI summary

End members (604) are supportable along a damper housing (200) and dimensioned for securement to a flexible spring member (300). The end members (604) include a wall (616) with a first wall portion (618) having an outer surface portion (622) dimensioned to receivingly engage the flexible spring member (300). A second wall portion (650) includes an inner surface portion (650A) dimensioned to receivingly engage a torsional isolator (700) supported on the damper housing (200). A third wall portion (652) extends radially outward beyond the second wall portion (650) and includes a passage surface (662) at least partially defining a passage (602) extending axially through the third wall portion (652). The passage (602) is dimensioned to receive a projection (732) of the torsional isolator (700). 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.