Ball Socket Bearing Composition for Fracture-Free Ball Stud Insertion
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Solution Overview
Problem
Existing ball joint bearings made as monolithic pieces face challenges in withstanding the insertion of a ball stud without fracturing, particularly due to the lack of sufficient elasticity and strength.
Innovation Solution
A ball socket assembly featuring a bearing made of 8-12% polytetrafluoroethylene and 2-6% carbon fibers with a hardened Nitrox layer on the ball stud, which includes an oxide and compound zone, providing enhanced elasticity and strength to accommodate the ball stud's insertion without breaking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the bearing is made as a monolithic piece of plastic material, then the bearing can be manufactured with high precision and smooth surfaces, but the bearing lacks sufficient elasticity to deform during ball stud insertion without fracturing
Solution Approach 1:
The bearing is constructed as a composite structure with an outer elastic shell made of rubber or elastomer material and an inner monolithic plastic bearing insert. This composite design allows the outer shell to provide elasticity and deform during ball stud insertion, while the inner plastic insert maintains manufacturing precision and provides the smooth bearing surface for low-friction operation.
2Strength
If the bearing material is made more elastic to allow deformation during insertion, then the bearing can accommodate ball stud insertion without fracturing, but the bearing loses manufacturing precision and surface integrity
Solution Approach 1:
The bearing combines an elastic outer shell with a precision-machined inner plastic insert. The outer shell provides the necessary elasticity for deformation during insertion, while the inner insert is manufactured separately with high precision to ensure smooth bearing surfaces and proper geometric accuracy.
Solution Approach 2:
The bearing is divided into two functional segments: an outer elastic shell that handles deformation and insertion forces, and an inner monolithic plastic insert that provides the precision bearing surface. This segmentation allows each component to be optimized for its specific function without compromise.
3Ease of manufacture
If the ball stud is inserted into the bearing without a hardened layer, then the assembly process is simpler, but the ball stud and bearing experience excessive wear and reduced operating life
Solution Approach 1:
A hardened layer is applied to the ball stud surface through nitriding or other surface treatment processes. This changes the surface properties of the ball stud, providing enhanced wear resistance and durability while maintaining the overall simplicity of the assembly process. The hardened layer enables longer operating life without complicating the manufacturing or assembly procedures.
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 solution significantly improves the strength and durability of the ball socket assembly, reducing the risk of fracture during assembly and enhancing the operating life by up to 60% and corrosion resistance by 75%, while maintaining low friction and wear resistance.
Implementation Method 1
it must be constructed in such a way that the ball stud can be inserted into the bearing without fracturing, or otherwise breaking the bearing. One approach to solving this problem is to make the bearing out of a material that has a high elasticity so that the bearing can deform elastically when the ball stud is inserted into a ball cavity of the bearing.
Implementation Method 2
The ball stud having a hardened layer along at least a portion of its outer surface, the hardened layer being a Nitrox layer.
Data Source
AI summary
The ball socket assembly includes a housing with an inner bore and a bearing that is received in the inner bore of the housing. The bearing is made as a monolithic piece of a plastic material and has a curved bearing surface which surrounds a ball cavity. A ball stud, which has a ball portion and a shank portion, is received in the ball cavity of the bearing. The ball portion has an equator. The curved bearing surface of the bearing is in slidable contact with the ball portion of the ball stud on opposite axial sides of the equator. The plastic material of the bearing comprises 8-12 mass percent polytetrafluoroethylene, 2-6 mass percent carbon fibers, and the remainder acetal. The ball stud having a hardened layer along at least a portion of its outer surface, the hardened layer being a Nitrox layer.