Elastomer Joint Wire Ring Locking Axial Load

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Solution Overview

Problem

Elastomer joints in motor vehicle chassis parts face issues with tilting moments under axial loads, leading to potential detachment and fatigue failure due to the use of Seeger rings, which have limited circular overlap and rectangular cross-sections.

Innovation Solution

The use of a wire ring with a circular, polygonal, or oval cross-section as a locking element, providing a larger circular coverage and preventing tilting moments, ensuring secure positioning and reducing stress on support rings, thereby enhancing operational reliability and preventing fatigue fractures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a Seeger ring with rectangular cross-section is used as a locking element, then the elastomer joint can be assembled easily and the locking element can be obtained cheaply as a standard part, but under axial loads a tilting moment acts on the Seeger ring which may result in the circlip being dislodged from the housing groove and frequent axial displacements causing fatigue failure

Engineering Contradiction:
Improveavailability as standard partVSAvoidretention under axial load
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent changes the cross-sectional geometry parameter of the locking element from rectangular (Seeger ring) to circular wire ring. This parameter change eliminates the tilting moment effect under axial loads while maintaining the advantage of using readily available standard parts, thus resolving the contradiction between ease of manufacture and reliability under load.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent applies spheroidality by using a circular cross-section wire ring instead of a rectangular cross-section Seeger ring. The circular geometry ensures that forces are distributed evenly around the ring, preventing tilting moments and enhancing reliability under axial loads while maintaining ease of assembly.

Inventive Principle:
Principle #14Spheroidality (Curvature)

2Device complexity

If a Seeger ring with 270° circular overlap is used, then the locking element has simple geometry and can be manufactured easily, but the limited circular coverage increases the risk of detachment under load

Engineering Contradiction:
Improvegeometry of locking elementVSAvoidretention under axial load
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent changes the circular coverage parameter from 270° (Seeger ring) to 360° (wire ring). This complete circular coverage provides uninterrupted locking action around the entire pivot pin, eliminating the risk of detachment at the gap location while maintaining simple circular geometry that is easy to manufacture and install.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If a wire ring with circular cross-section is used as a locking element, then no tilting moments occur under axial loads and the pivot pin is held securely, but the wire ring requires specific groove contour adaptation to match its cross-section

Engineering Contradiction:
Improveretention under axial loadVSAvoidgroove contour adaptation
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent applies local quality by adapting only the local groove contour at the housing to match the circular cross-section of the wire ring. This localized modification ensures proper fit and prevents tilting moments without requiring complex changes to the overall joint design, thus achieving high reliability with minimal manufacturing complexity.

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 wire ring effectively secures the pivot pin within the housing without tilting or axial displacement, even under axial loads, significantly improving the operational reliability and preventing damage to the elastomer joint, as demonstrated by comparative tests showing no signs of fracture on the support ring under the same loads.

Implementation Method 1

The locking element is formed from a wire ring. The wire ring can have a substantially circular cross section.

Methodology Applied
Scientific EffectGeometry: Geometry

Data Source

PatentEP2414180B1Elastomer articulation
Publication Date: 2014.10.08 ZF AUTOMOTIVE GERMANY GMBH
  • EP2414180B1 patent drawingFigure 1~2
  • EP2414180B1 patent drawingFigure 3~4
  • EP2414180B1 patent drawingFigure 5

AI summary

The invention relates to an elastomeric joint (10), having a housing (12) with a through opening (14) which extends axially along the longitudinal axis (16) of the elastomeric joint, a pivot (18) which extends through the through opening (14) of the housing (12), an elastomer body (20) which is fastened to the pivot (18) and is arranged radially between the pivot (18) and the housing (12), and with at least one supporting ring (22) which is fastened to the elastomer body (20) on one end side of the through opening (14), wherein a wire ring (32) locks the supporting ring (22) with respect to the housing (12), with the result that the pivot (18) is held in the housing (12) in an axially secured manner.