Ball Joint Structure With Insert-Molded Stepped Bearings

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Solution Overview

Problem

Conventional ball joint manufacturing processes are costly and weight-intensive, leading to increased vehicle fuel consumption, and are prone to bearing damage during assembly due to complex assembly procedures and material limitations.

Innovation Solution

A ball joint structure featuring a metal reinforcement with a knurled interior and insert-molded synthetic resin ball housing, utilizing stepped bearings to prevent resin flow and enhance coupling strength, simplifying assembly and reducing weight.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If metal reinforcement is manufactured by casting and grinding, then strength is improved, but weight increases and manufacturing cost increases

Engineering Contradiction:
ImprovestrengthVSAvoidweight
Core Design Contradiction:
StrengthVSWeight of moving object

Solution Approach 1:

The ball joint is divided into multiple components: metal reinforcement, bearing, cap, ball stud, and dust cover. Each component is optimized independently - the metal reinforcement provides strength while being designed with minimal material, and the bearing is separately manufactured and pressed into the reinforcement, allowing weight reduction without compromising overall strength.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The ball joint uses composite construction combining metal reinforcement (for strength) with plastic bearing material (for weight reduction and self-lubrication). This composite approach allows the structure to achieve both high strength and low weight by selecting materials optimized for their specific functions rather than using a single heavy material throughout.

Inventive Principle:
Principle #40Composite materials

2Strength

If metal reinforcement is manufactured by casting and grinding, then strength is improved, but manufacturing cost increases

Engineering Contradiction:
ImprovestrengthVSAvoidmanufacturing cost
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

The ball joint is divided into multiple components: metal reinforcement, bearing, cap, ball stud, and dust cover. Each component is optimized independently - the metal reinforcement provides strength while being designed with minimal material, and the bearing is separately manufactured and pressed into the reinforcement, allowing weight reduction without compromising overall strength.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention uses simpler, more cost-effective manufacturing processes for each component. The metal reinforcement is cast rather than ground, the bearing is molded from plastic rather than machined from metal, and assembly uses simple pressing and bending operations. These simpler processes reduce manufacturing cost while maintaining adequate strength through intelligent design.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Productivity

If bearing is press-fitted into metal reinforcement, then assembly is completed, but bearing is often damaged

Engineering Contradiction:
Improveassembly completionVSAvoidbearing damage
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The bearing is designed with sufficient press-fit clearance and the metal reinforcement is designed with appropriate tolerance ranges to cushion the pressing force. The pressing operation is performed with controlled force to prevent damage, and the bearing material is selected for its ability to withstand pressing without cracking or deforming.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The invention changes the material parameters by using plastic bearing material instead of metal, which allows for more flexible pressing operations. The plastic material can deform elastically during pressing and then settle into its final position, reducing the risk of damage compared to rigid metal bearings that would require precise, high-force pressing.

Inventive Principle:
Principle #35Parameter changes

4Productivity

If deformable portion is bent to assemble cap with metal reinforcement, then assembly is completed, but manufacturing process becomes complicated and components may be damaged

Engineering Contradiction:
Improveassembly completionVSAvoidmanufacturing process complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The ball joint is divided into multiple components: metal reinforcement, bearing, cap, ball stud, and dust cover. Each component is optimized independently - the metal reinforcement provides strength while being designed with minimal material, and the bearing is separately manufactured and pressed into the reinforcement, allowing weight reduction without compromising overall strength.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention changes the material parameters by using plastic bearing material instead of metal, which allows for more flexible pressing operations. The plastic material can deform elastically during pressing and then settle into its final position, reducing the risk of damage compared to rigid metal bearings that would require precise, high-force pressing.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP2465713B1Ball joint structure and manufacturing method thereof
Publication Date: 2016.12.07 ILJIN CO LTD
  • EP2465713B1 patent drawingFigure 1
  • EP2465713B1 patent drawingFigure 2
  • EP2465713B1 patent drawingFigure 3

AI summary

The present invention relates to a ball joint structure and a manufacturing method thereof, which can simplify a manufacturing process, can reduce a weight thereof, and can secure durability thereof, simultaneously. The ball joint structure according to an exemplary embodiment of the present invention includes: a ball stud having a ball formed at one end thereof; a bearing including a first bearing coupled to the ball for an interior surface thereof to slide on an exterior surface of the ball and covering an exterior surface of one side of the ball, and a second bearing coupled to the ball for an interior surface thereof to slide on the exterior surface of the ball and covering an exterior surface of the other side of the ball; and a ball housing which is insert-molded together with the bearing to cover the outside of the bearing. Accordingly, the present invention improves assembly availability by separately mounting the first bearing and the second bearing on the ball formed at the ball stud, and prevents permeation of resin by forming stepped parts between the first bearing and the second bearing when the ball housing is insert-molded.