Steering Shaft Universal Joint Bearing for Higher Preload Load
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing universal joint designs for motor vehicle steering shafts face challenges in achieving high rigidity and permissible bearing load due to complex high-precision machining requirements and limited axial length for rolling element raceways, which restricts the extension of pins and increases manufacturing effort.
Innovation Solution
A universal joint design featuring a pot-shaped outer sleeve and an integrally attached inner sleeve with a convex contact area on the pin, allowing for a larger axial width of the rolling element raceway and increased permissible bearing load, while also enabling elastic prestressing and improved power transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the journal is extended in the axial direction to increase the rolling element raceway width, then the permissible bearing load increases, but the insertion of the universal joint into the joint yoke becomes difficult or impossible
Solution Approach 1:
The journal is divided into two functional segments: a basic journal portion that fits within the joint yoke and maintains ease of insertion, and an extended journal portion that protrudes axially to provide additional rolling element raceway width. This segmentation allows the journal to simultaneously achieve high permissible bearing load through the extended raceway area while maintaining compatibility with the joint yoke dimensions for proper installation.
2Reliability
If high-precision machining of the journal is performed to achieve play-free running and high rigidity, then the bearing performance improves, but the manufacturing complexity and effort increase
Solution Approach 1:
An intermediary element, specifically a pressing member or adjustment mechanism, is introduced to apply axial preload to the journal bearing. This intermediary allows the bearing to be preloaded in a controlled manner after assembly, achieving play-free running and high rigidity without requiring extremely tight manufacturing tolerances on the journal itself, thereby reducing manufacturing complexity while maintaining bearing performance.
3Stability of the object's composition
If the convex end face of the journal is used for elastic preload, then the rigidity of the joint arrangement increases, but the axial area available for the rolling element raceway is shortened
Solution Approach 1:
The journal surface is segmented into distinct functional zones: a convex end face portion dedicated to elastic preload contact that provides joint rigidity, and an extended axial portion that serves as the rolling element raceway. This spatial segmentation of functions allows the convex end face to provide preload without encroaching on the rolling element raceway width, as the raceway extends along the axial length of the extended journal portion.
Solution Approach 2:
The solution transitions from using the limited axial width of a standard journal for both preload and raceway functions to utilizing the extended axial dimension of a longer journal. By increasing the axial length of the journal, there is sufficient space to accommodate both the convex preload face at one end and the rolling element raceway along the extended portion, effectively resolving the spatial conflict through dimensional expansion.
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 design enhances the universal joint's rigidity and bearing capacity by increasing the axial width of the rolling element raceway, reducing manufacturing complexity, and allowing for better radial support and power transmission with a more efficient contact area configuration.
Implementation Method 1
rolling elements which can roll are arranged between the pin and the outer bushing
Implementation Method 2
Through elastic deformation of the outer cup base outward in the axial direction of the journal axis, the outer bush permanently exerts an elastic preload force on the pair of journals
Data Source
Figure 1~4
Figure 5~8
Figure 9~11
AI summary
The present invention relates to a universal joint (5) for a steering shaft (23, 25) of a motor vehicle, comprising a crosspiece (55) having two pairs of journals (56) arranged at right angles to one another and two joint yokes (51, 3) which can be connected to the steering shaft (23, 25) and have in each case two arms (52, 54) opposite one another, in each of which arms a journal (56) is mounted so as to be rotatable about a journal axis (Z) in a journal bearing (6), which has a pot-shaped outer sleeve (61) fixed in the arm (52, 54), which outer sleeve has an outer pot base (611) opposite the end face of the journal (56), wherein rollable rolling elements (63) are arranged between the pin (56) and the outer sleeve (61), and wherein a convexly projecting contact region (58, 64) is arranged on the end face of a journal (56), which contact region contacts the outer pot base (611). According to the invention, in order to provide a joint assembly that allows a greater bearing load during preloaded bearing of a crosspiece (55), an inner sleeve (62) is fixed on the journal (56), wherein the rolling elements (63) are arranged between the inner sleeve (62) and the outer sleeve (61) and the contact region (58, 64) projects axially on the end face relative to the inner sleeve (62).