Cage-Structured Ball Joint Insert for Pull-Out Retention

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Solution Overview

Problem

Existing ball joint inserts in motor vehicles face challenges in positioning and handling due to complex tooling requirements and limited pull-out force, especially when made of plastic, which restricts the freedom of movement and increases the risk of the joint ball being pulled out with insufficient force.

Innovation Solution

A cage-like design for the insert with a cap element and reinforcement elements allows for improved positioning and handling, enabling a higher pull-out force by surrounding the joint ball with a material that can be overmolded, while maintaining the ability to rotate and tilt the joint ball.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a cap element is used to cover the pole face, then rotational movement is enabled, but positioning and handling becomes complex

Engineering Contradiction:
Improverotational movement capabilityVSAvoidpositioning and handling complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The cap element is integrated into the cage-like structure, where the cap element is positioned within the cage structure and both components work together as a unified assembly. The cap element covers the pole face while the cage structure provides the necessary positioning and handling features, eliminating the need for separate positioning mechanisms.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Ease of manufacture

If plastic material is used for joint shell, then manufacturing is simplified, but pull-out force becomes insufficient

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidpull-out force
Core Design Contradiction:
Ease of manufactureVSForce

Solution Approach 1:

The joint shell is constructed as a composite structure combining plastic material with integrated reinforcement elements. The reinforcement elements, which can be made of metal or other high-strength materials, are embedded within or attached to the plastic joint shell, creating a composite structure that maintains the manufacturing simplicity of plastic while significantly increasing the pull-out force capability.

Inventive Principle:
Principle #40Composite materials

3Strength

If reinforcement elements are added to increase pull-out force, then structural strength is improved, but device complexity increases

Engineering Contradiction:
Improvepull-out forceVSAvoidstructural complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The reinforcement elements are merged with the joint shell and cap element to form an integrated structure. The reinforcement elements are strategically positioned within the joint shell and connected to the cap element, creating a unified structural system that increases pull-out force without requiring separate, complex reinforcement systems.

Inventive Principle:
Principle #5Merging (Combining)

4Ease of operation

If the insert is designed to surround the ball joint, then positioning is improved, but overmolding complexity increases

Engineering Contradiction:
Improvepositioning capabilityVSAvoidovermolding complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The insert is segmented into distinct functional components: the cage-like structure for positioning, the cap element for covering the pole face, and the integrated reinforcement elements for strength. This segmentation allows each component to be optimized for its specific function while simplifying the overall overmolding process, as each segment can be molded independently or in controlled sequences.

Inventive Principle:
Principle #1Segmentation

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 cage-like design enhances the insert's positionability and handling, increases the pull-out force, and reduces the risk of the joint ball being pulled out with a force below the required threshold, while allowing for both rotational and tilting movements.

Implementation Method 1

an open substructure which provides a cage-like structure for surrounding the ball joint, wherein the injection molding compound can penetrate the open substructure

Methodology Applied
Scientific EffectInjection molding:

Implementation Method 2

the cap element sufficiently seals an internal free space between the pole face and the cap element so that no injection molding compound can enter the free space during overmolding

Methodology Applied
Scientific EffectSealing:

Data Source

PatentEP3589851B1Insert for a ball joint in a motor vehicle, ball joint or link having an insert of this type, and method for producing an insert of this type, a ball joint of this type or a link of this type
Publication Date: 2021.05.26 ZF FRIEDRICHSHAFEN AG
  • EP3589851B1 patent drawingFigure 1
  • EP3589851B1 patent drawingFigure 2
  • EP3589851B1 patent drawingFigure 3

AI summary

The invention relates to an insert (1) for a ball joint in a motor vehicle having a first part structure (6) for making contact with a joint ball (2) which is mounted at least partially slidingly, wherein the first part structure can be connected to a joint shell and/or a joint housing by means of overmoulding. In order to improve the positionability and/or handleability of the insert, in particular in order to realize an increase in the pulling-out force in addition to a pole surface cover, the insert is characterized in that a cage-like configuration for surrounding the joint ball is realized by means of an open part structure (20).