Ball Joint Dust Cover Stacking Prevention Design

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Solution Overview

Problem

Conventional dust covers for ball joints with an outer periphery fitted to an inner socket surface tend to have film portions contact each other when stacked, leading to sticking and damage during peeling and conveyance, and are prone to deviation and contact due to vibration.

Innovation Solution

A dust cover design featuring a cylindrical one-end large-diameter opening portion with a reinforcing ring, a flange portion, and film portions made of rubber-like elastic material with outside and inside projections that contact each other when stacked, preventing film contact and deformation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the dust cover is designed with outer periphery fitted to inner socket surface, then the fitting precision is improved, but the film portions contact each other when stacked causing sticking and damage

Engineering Contradiction:
Improvefitting precisionVSAvoidpeeling ease
Core Design Contradiction:
Manufacturing precisionVSEase of operation

Solution Approach 1:

The dust cover is divided into a hard portion (cylindrical opening portion) and a flexible film portion. The hard portion provides precise fitting to the socket while the flexible film portion can deform to prevent contact between stacked covers, resolving the contradiction between fitting precision and peeling ease.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The dust cover utilizes materials with different physical properties - a rigid material for the cylindrical opening portion to ensure precise fitting, and a flexible rubber-like material for the film portion to allow deformation and prevent sticking during stacking and peeling operations.

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If outer peripheral projections are formed on the film portion to avoid contact, then the film contact is prevented, but the dust covers deviate due to vibration during conveyance

Engineering Contradiction:
Improvestacking reliabilityVSAvoidalignment stability
Core Design Contradiction:
Ease of operationVSStability of the object's composition

Solution Approach 1:

The dust cover is segmented into a rigid cylindrical opening portion that maintains structural stability and alignment during conveyance, and a flexible film portion that can deform to prevent contact. This segmentation allows the rigid part to resist vibration while the flexible part prevents sticking.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different parts of the dust cover have different mechanical properties - the cylindrical opening portion is rigid to maintain alignment stability during conveyance, while the film portion is flexible to prevent contact between stacked covers. This local differentiation of material properties resolves the contradiction between stacking reliability and alignment stability.

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

Effectively prevents film contact and deformation during stacking and conveyance, ensuring proper alignment and reducing damage, even under vibration.

Implementation Method 1

a film portion coupling an inward end portion of the flange portion and the other-end small-diameter opening portion and made of a rubber-like elastic material

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3144549B1Dust cover for ball joint
Publication Date: 2018.10.03 NOK CORP
  • EP3144549B1 patent drawingFigure 1~2
  • EP3144549B1 patent drawingFigure 3~4
  • EP3144549B1 patent drawingFigure 5~6

AI summary

The purpose of the present invention is to provide a dust cover for a ball joint, the dust cover being configured so that, even such dust covers are stacked on each other, the diaphragm sections thereof do not come into contact with each other. A spherical head formed at one end of a ball stud is held within a socket, and a shaft at the other end of the ball stud is fastened and affixed to a knuckle. A dust cover for a ball joint is configured in such a manner that: a circular cylindrical large-diameter opening at one end of the dust cover, the large-diameter opening having a large-diameter opening-side reinforcement ring embedded therein, is affixed to and held on the inner peripheral surface of the socket; and a small-diameter opening at the other end of the dust cover is held on the outer peripheral surface of the shaft. The dust cover for a ball joint comprises: a flange section extending from an end section of the large-diameter opening at said end, the end section facing the small-diameter opening at the other end, toward the ball stud; and a drum-shaped diaphragm section consisting of a rubber-like elastic material and connecting the inner end section of the flange section and the small-diameter opening at the other end. The dust cover for a ball joint further comprises: an outer protrusion formed on the outer peripheral surface of the diaphragm section; and an inner protrusion provided on the inner peripheral surface of the joint where the flange section and the diaphragm section are joined. The dust cover for a ball joint is adapted so that, when such dust covers are stacked on each other, the outer protrusion and the inner protrusion are in contact with each other.