Ball Joint Bead Design for Sealing and Strength

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Solution Overview

Problem

Existing ball pivot technologies are costly and complex to produce, often requiring specialized tools and methods that can compromise the sealing effect in ball joints, especially when using cylindrical sections which have lower flexural strength and are difficult to manufacture.

Innovation Solution

A ball pivot designed in two parts, where the trunnion and ball are manufactured separately and connected later, using a multi-stage press process with axial deformation to create a bead and fastening groove, allowing for cost-effective and flexible production without the need for complex tools.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a cylindrical section is used in the ball pivot design, then the manufacturing process becomes simpler, but the flexural strength decreases

Engineering Contradiction:
Improvemanufacturing process simplicityVSAvoidflexural strength
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

The patent applies local quality by transitioning from a uniform cylindrical section to a non-uniform profile with varying wall thickness. The bead structure creates localized thickening at critical positions while maintaining thinner sections elsewhere, optimizing both strength and manufacturability. This is achieved through axial deformation that forms a bead with different wall thicknesses in different regions, providing enhanced flexural strength where needed while keeping the overall manufacturing process simple.

Inventive Principle:
Principle #3Local quality

2Ease of operation

If a conical section is used in the ball pivot design, then the angular mobility is improved, but the manufacturing complexity increases

Engineering Contradiction:
Improveangular mobilityVSAvoidmanufacturing complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent segments the ball pivot structure into distinct functional sections: a conical section for angular mobility, a cylindrical section for structural support, and a bead for sealing. This segmentation allows each section to be optimized for its specific function while being manufactured as an integrated component through a multi-stage press process, balancing performance requirements with manufacturing feasibility.

Inventive Principle:
Principle #1Segmentation

3Manufacturing precision

If specialized tools are used for production, then the manufacturing precision is improved, but the production cost increases

Engineering Contradiction:
Improveproduction precisionVSAvoidproduction cost
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent employs a multi-stage press process where the forming tool itself creates the bead structure through controlled axial deformation. The tool serves multiple functions: shaping the conical section, forming the cylindrical section, and creating the bead profile in sequence. This self-service approach eliminates the need for specialized secondary tools while maintaining manufacturing precision through the integrated forming process.

Inventive Principle:
Principle #25Self-service

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 approach enables the production of ball pivots with enhanced angular mobility and sealing effectiveness, reducing production costs and simplifying the manufacturing process while maintaining high performance in ball joints.

Implementation Method 1

The bead was produced by purely axial forming. This means that the forming movement of the forming tool is purely axial.

Methodology Applied
Scientific EffectAxial deformation: Deformation

Implementation Method 2

The bead has two bevels and was produced in a split tool by cold forming, in particular upsetting or extrusion.

Methodology Applied
Scientific EffectCold forming: Cold-forming

Data Source

PatentEP2336581B1Ball joint
Publication Date: 2016.01.13 KAMAX HLDG GMBH & CO KG
  • EP2336581B1 patent drawingFigure 1
  • EP2336581B1 patent drawingFigure 2a~2b
  • EP2336581B1 patent drawingFigure 3

AI summary

A ball stud (1) has a stud end (2) and a ball (15). The stud end (2) has a first free end (3), a threaded section (4), a fastening groove (9) for attaching a bellows (22) or the like to the stud end (2), a conical section (12), and a second end (13). The threaded section (4) is located in the region of the first free end (3) or at least adjacent to it. The fastening groove (9) is arranged axially between the threaded section (4) and the conical section (12) and is bounded at its axial end facing the conical section (12) by a bead (10). The conical section (12) is arranged axially between the bead (10) and the second end (13). The ball (15) is connected to the second end (13) of the stud end (2).The bead (10) is produced by axial forming, and a cylindrical section (11) is arranged axially between the bead (10) and the conical section (12). The stub stud (2) and the ball (15) were produced separately and only joined together after forming, so that the ball stud (1) is formed in two parts in this respect.