Ball Joint Anti Pull-Out Collar for Outer Race Expansion
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Solution Overview
Problem
Ball joints fail due to radial expansion of the outer race, causing the ball and stem to pull out under axial loads, which existing designs fail to prevent effectively.
Innovation Solution
An anti pull-out collar is integrated around the outer race, featuring a complementary profile and interference fit to prevent radial expansion, ensuring the ball and stem remain securely in place by engaging the outer race and bearing housing, thereby enhancing load capacity and fatigue resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the stepped flange is designed with sufficient radial thickness to prevent radial deformation, then the ball joint reliability improves, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
The invention divides the outer race into functional segments: the original stepped flange structure and the added anti-pull-out collar. The collar is a separate component that can be installed independently, allowing the main outer race to maintain its original simple design while the collar provides the additional radial support needed to prevent deformation under axial loads.
Solution Approach 2:
The anti-pull-out collar acts as an intermediary element between the outer race and the bearing housing. It mediates the radial expansion forces by providing additional structural support in the form of a collar with increased radial thickness, thereby preventing the ball from pulling out without requiring redesign of the entire outer race structure.
2Strength
If the outer race radial thickness is increased to prevent radial expansion, then the load-bearing capacity improves, but the manufacturing precision requirements and material usage increase
Solution Approach 1:
Instead of increasing the radial thickness of the entire outer race, the invention segments the load-bearing function by adding a separate anti-pull-out collar. This collar contains the increased radial thickness only in the specific region where it is needed to prevent radial expansion, thereby reducing manufacturing complexity and material usage compared to thickening the entire outer race structure.
Solution Approach 2:
The anti-pull-out collar applies local quality enhancement by providing increased radial thickness and structural support only in the specific area where radial expansion occurs under axial loads. This localized reinforcement achieves the required load-bearing capacity without unnecessarily increasing the dimensions or complexity of the entire outer race structure.
3Reliability
If an anti pull-out collar is added to prevent radial expansion, then the ball joint reliability improves, but the device complexity increases
Solution Approach 1:
The invention segments the ball joint structure by adding the anti-pull-out collar as a distinct component. This segmentation allows the collar to be designed, manufactured, and installed independently, simplifying the overall system architecture while providing the necessary reliability improvement through targeted radial support.
Solution Approach 2:
The anti-pull-out collar serves multiple functions: it prevents radial expansion of the outer race, provides additional structural support under axial loads, and maintains the spherical bearing surface alignment. By consolidating these functions into a single component, the invention improves reliability without proportionally increasing device complexity.
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 anti pull-out collar effectively prevents radial expansion of the outer race, enhancing the load-bearing capacity and reliability of the ball joint by maintaining the ball and stem within the outer race, even under significant axial loads, thus preventing failure.
Implementation Method 1
The anti pull-out collar has an inside surface having a profile that is complementary in shape to the exterior surface of the outer race and configured to prevent radial expansion of the outer race
Data Source
Figure 1A
Figure 1B~2
Figure 3
AI summary
A ball joint (10, 210, 310) includes an outer race (14, 214, 314) having an exterior surface (14B, 214B, 314B) extending from an outer axial end (14C, 214C, 314C) to an inner axial end (14D, 214D, 314D) thereof and having an interior area that has an opening (14X, 214X, 314X) proximate the outer axial end (14C, 214C, 314C). The ball joint (10, 210, 310) includes a ball (11, 211, 311) with a stem (12, 212, 312) extending therefrom. The ball (11, 211, 311) is disposed in the interior area with the stem (12, 212, 312) extending out of the opening (14X, 214X, 314X). The ball joint (10, 210, 310) has an anti pull-out collar (20, 220, 320) disposed around the outer race (14, 214, 314) and located entirely beyond a center point (P) of the ball (11, 211, 311) towards the outer axial end 14C, 214C, 314C) of the outer race (14, 214, 314). The anti pull-out collar (20, 220, 320) has a radial thickness (T21, T22, T230, T330) configured to prevent radial expansion of the outer race (14, 214, 314).