Universal Joint Slip Bush Guide Ball Friction Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional universal joints experience high sliding frictional forces between solid parts and the tube, leading to reduced torsional fracture strength and safety factors, especially during impacts or strong rotational forces, which can cause the universal joint to fail in absorbing impacts and maintaining driver safety.
Innovation Solution
Incorporating guide balls into rows of guide holes in the slip bush's circumferential wall, which reduce sliding friction and produce rolling friction when rotational torque is applied, and serve as supports during torsional fracture torque, enhancing the universal joint's collapse and torsional strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If solid parts are used in the slip bush to engage with the tube, then torsional fracture strength is improved, but sliding frictional force increases reducing smooth collapse
Solution Approach 1:
Guide balls are introduced as intermediary elements between the slip bush and the tube. These guide balls engage with guide holes in the slip bush and the inner circumferential surface of the tube, converting direct sliding contact into ball-mediated rolling contact. This intermediary mechanism reduces sliding friction while maintaining engagement strength.
Solution Approach 2:
The patent replaces the traditional sliding friction-based mechanical engagement with a rolling friction-based system using guide balls. By substituting sliding contact with rolling contact, the mechanical interaction achieves lower friction coefficients while maintaining the necessary engagement and torque transmission capabilities.
2Ease of operation
If guide balls are added to reduce friction, then smooth collapse is improved, but device complexity increases
Solution Approach 1:
The guide balls serve multiple functions simultaneously: they reduce friction during normal operation, provide impact absorption during collapse, and maintain engagement between the slip bush and tube. This multi-functionality allows a single added component to address multiple performance requirements without proportionally increasing complexity.
Solution Approach 2:
The patent changes the friction parameter by introducing guide balls that transform sliding friction into rolling friction. This parameter change achieves smooth collapse operation while the guide balls are integrated into the existing slip bush structure through guide holes, minimizing the increase in device complexity.
3Ease of operation
If guide balls are used to reduce sliding friction, then smooth collapse is achieved, but torsional fracture strength may be reduced
Solution Approach 1:
The guide balls are pre-positioned within guide holes that are formed during the slip bush manufacturing process. This preliminary integration ensures that the guide balls are properly positioned to reduce friction during collapse while also being strategically located to provide torsional support when needed, achieving both smooth collapse and adequate strength.
Solution Approach 2:
The patent creates a composite engagement system combining the plastic slip bush material with hardened guide balls (typically steel). This composite structure leverages the low friction properties of the guide balls while maintaining the torsional strength of the slip bush, achieving both smooth collapse and adequate torsional fracture strength through material combination.
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 effectively reduces sliding friction, allowing smooth collapse and improves torsional fracture strength, thereby enhancing safety factors by converting sliding friction into rolling friction and providing support during torsional loads.
Implementation Method 1
the guide balls reduce sliding frictional force while producing rolling frictional force so that the universal joint can be smoothly collapsed
Data Source
AI summary
Universal joint having slip bush including a tube, a slip bush inserted into the tube, and a shaft inserted into and slidably engaged with the tube via the slip bush. The universal joint further includes: one or more rows of guide holes formed by perforating a circumferential wall of the slip bush, the rows being arranged in the longitudinal direction of the slip bush; one or more guide balls fitted in the guide holes, respectively; and one or more C-type parts longitudinally formed on the circumferential wall of the slip bush. When axial pressure is applied to the universal joint in a state in which rotational torque is applied to the universal joint, the guide balls fitted in the guide holes come into contact with the inner circumferential surface of the tube, thereby reducing sliding frictional force while producing rolling frictional force so that the universal joint can be smoothly collapsed. In addition, the guide balls serve as supports when torsional fracture torque is applied to the slip bush, thereby improving the torsional fracture strength, which in turn improves a safety factor.