Ball Joint Housing Bead Structure for Equal-Wall Press Forming

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Solution Overview

Problem

The existing ball joint manufacturing process requires different thicknesses for the bottom and peripheral walls, limiting manufacturing flexibility, increasing weight, processing loads, and costs due to the need for specific welding and press working processes.

Innovation Solution

A ball joint design with a metal housing having a bottomed cylindrical shape formed by sheet-metal press work or forging, featuring bead portions on the bottom wall and recessed grooves on the outer bottom to achieve equal thickness for both, allowing for weight reduction and simplified manufacturing while maintaining stiffness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the bottom wall is made thicker to withstand axial load, then the load-bearing capacity is improved, but the weight and manufacturing cost increase

Engineering Contradiction:
Improveload-bearing capacityVSAvoidhousing weight
Core Design Contradiction:
StrengthVSWeight of moving object

Solution Approach 1:

The patent applies local quality by providing reinforcement ribs only at specific locations on the bottom wall where axial loads are concentrated, rather than uniformly thickening the entire bottom wall. This allows the housing to withstand axial loads while minimizing overall weight increase.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent employs composite material construction by combining the metal housing with a resin ball seat and resin reinforcement elements. This composite approach allows the metal housing to maintain adequate thickness while the resin components provide additional structural support, reducing the need for excessive metal material.

Inventive Principle:
Principle #40Composite materials

2Strength

If different thicknesses are required for bottom and peripheral walls, then the axial load resistance is improved, but the manufacturing process complexity increases

Engineering Contradiction:
Improveaxial load resistanceVSAvoidmanufacturing process flexibility
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

The patent uses local quality by adding reinforcement ribs at specific locations on the bottom wall rather than creating a complex variable thickness structure. This maintains manufacturing simplicity while providing the necessary axial load resistance through localized strengthening.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent segments the reinforcement function by separating the main housing structure from the reinforcement ribs. The ribs are added as distinct structural elements that can be formed through relatively simple press working processes, avoiding the need for complex variable thickness forming.

Inventive Principle:
Principle #1Segmentation

3Strength

If the bottom wall is made thicker, then the axial load capacity is improved, but the manufacturing cost increases

Engineering Contradiction:
Improveaxial load capacityVSAvoidmanufacturing cost
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

The patent applies local quality by providing reinforcement ribs only where axial loads are concentrated on the bottom wall, rather than uniformly increasing thickness. This significantly reduces material consumption and manufacturing cost while maintaining adequate load capacity.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent uses composite material construction combining metal housing with resin ball seat and reinforcement elements. This allows the metal housing to remain relatively thin while achieving the required axial load capacity through the combined structural system, reducing material costs.

Inventive Principle:
Principle #40Composite materials

4Strength

If reinforcement structures are added to maintain stiffness with equal thickness, then the deformation strength is improved, but the manufacturing complexity increases

Engineering Contradiction:
Improvedeformation strengthVSAvoidhousing structure complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The patent applies local quality by adding reinforcement ribs at specific strategic locations on the bottom wall rather than creating a complex overall structure. This provides the necessary deformation strength through localized strengthening while keeping the overall housing structure simple and easy to manufacture.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP3832153B1Ball joint, stabilizer link, and method for manufacturing ball joint
Publication Date: 2023.11.29 NHK SPRING CO LTD
  • EP3832153B1 patent drawingFigure 1
  • EP3832153B1 patent drawingFigure 2
  • EP3832153B1 patent drawingFigure 3A~3B

AI summary

An axial ball joint is provided with: a ball stud including a stud section and a ball section; a metallic housing which rotatably supports the ball section of the ball stud; and a resin-made ball seat which is provided to be interposed between the ball section and the housing. The housing is formed into a bottomed cylinder shape by pressing. The thickness of a bottom wall and the thickness of a circumferential side wall of the housing are set to be equal to each other. A plurality of bead sections are formed on the inner bottom of the housing by press-molding or forging.