Universal Joint Bearing Clinching for Stable Press-Fit Assembly
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Solution Overview
Problem
Dimensional variations in the through-hole of the yoke or bearing in cross joints lead to unreliable clinching, potential looseness, and noise due to manufacturing errors and thermal expansion differences, affecting the fail-safe function in steering systems.
Innovation Solution
A manufacturing method and apparatus for a universal joint that involves temporarily assembling a bearing by press-fitting it to a first position in the yoke's through-hole and then clinching to press-fit it deeper to a second position, ensuring a stable press-fit with a distance of 0.05 mm or more, using separate shafts and a switching mechanism to facilitate this process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If clinching is performed at a constant amount to fix the bearing in the through-hole, then the manufacturing process is simple, but the clinching cannot be reliably performed due to dimensional variations in the through-hole or bearing, causing looseness
Solution Approach 1:
The bearing is temporarily assembled to a first position in the through-hole before clinching, establishing a preliminary position that ensures proper alignment and prevents looseness. This preliminary action allows the clinching to be performed reliably on top of the already-positioned bearing rather than attempting to position and clinch simultaneously.
2Reliability
If the bearing is press-fitted with negative clearance to prevent falling off, then the fail-safe function is achieved, but the clearance may decrease due to manufacturing errors and thermal expansion differences, causing the clinched portion and bearing to contact and generate noise
Solution Approach 1:
The bearing is temporarily assembled to a first position that provides preliminary support and prevents falling off, achieving the fail-safe function before clinching. This preliminary positioning ensures that the bearing is already supported by the clinched portion after clinching, preventing contact between the clinched portion and bearing that would generate noise.
3Reliability
If the bearing is press-fitted deeply into the through-hole to ensure stable contact, then the reliability of clinching is improved, but the manufacturing process becomes more complex requiring multiple shafts and switching mechanisms
Solution Approach 1:
The press-fitting process is segmented into two distinct stages: first, temporary assembly to a first position using a first shaft; second, final press-fitting to a second position using a second shaft after clinching. This segmentation allows each shaft to be optimized for its specific function, with the switching mechanism coordinating between them, making the complex process more controllable and reliable.
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
Enhances the reliability of the clinching process, reduces looseness and noise, and maintains the fail-safe function by ensuring consistent contact between the clinched portion and the bearing, even with different metal materials and thermal expansion variations.
Implementation Method 1
press-fitting the bearing to a first position in the through-hole of a yoke
Implementation Method 2
clinch a portion of the yoke around the through-hole
Implementation Method 3
press the bearing deeper into the through-hole with a clinched portion formed by the clinching
Data Source
Figure 1~2
Figure 3
Figure 4~5
AI summary
A method of manufacturing a universal joint includes: temporarily assembling a bearing (140), which supports a shaft portion (132a) of a joint spider (130) such that the shaft portion (132a) is rotatable, with respect to a through-hole (112a) and the shaft portion (132a) by press-fitting the bearing (140) to a first position (P1) in the through-hole (112a) of a yoke (110; 210); and clinching, after the bearing (140) is temporarily assembled, a portion of the yoke (110; 210) around the through-hole (112a), and pressing the bearing (140) deeper into the through-hole (112a) with a clinched portion (119) formed by the clinching to press-fit the bearing (140) to a second position (P2) located deeper than the first position (P1) in the through-hole (112a).