Universal Joint Yoke with Reduced Wall Thickness
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Solution Overview
Problem
Existing universal joint yokes face challenges in achieving optimal load distribution and longevity due to manufacturing complexities and uneven stress distribution, leading to reduced lifespan.
Innovation Solution
The design incorporates yoke arms with reduced wall thickness in the outer portions relative to the inner portions, featuring recesses that are partially parallel to the axis of rotation, which reduces Hertzian stress and enhances elasticity, allowing for more even load distribution and increased lifespan.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If the wall thickness of yoke arms is uniform throughout, then manufacturing is simpler, but stress distribution is uneven leading to reduced lifespan
Solution Approach 1:
The patent applies local quality by varying the wall thickness of the yoke arms according to the local stress distribution. The outer portions (subject to higher Hertzian stress from bearing loads) have reduced wall thickness, while inner portions maintain greater thickness. This non-uniform thickness distribution optimizes stress absorption and extends the lifespan of the joint yoke without requiring complex manufacturing processes, as the design follows the natural stress flow patterns.
2Reliability
If recesses are added to reduce Hertzian stress, then bearing performance improves, but manufacturing complexity increases
Solution Approach 1:
The patent introduces recesses in the outer portions of the yoke arms to locally modify the stress distribution. These recesses reduce the Hertzian contact stress in the high-loading zones where the bearing loads are transmitted. The recesses are strategically positioned to match the stress concentration areas, improving bearing performance and reliability while maintaining manufacturability through conventional forming processes.
3Strength
If wall thickness is reduced in outer portions, then stress concentration is reduced and elasticity increases, but structural strength may be compromised
Solution Approach 1:
The patent reduces the wall thickness specifically in the outer portions of the yoke arms where Hertzian stress from bearing loads is most concentrated. This local thinning reduces the stress concentration factor and increases local elasticity, allowing the structure to better absorb cyclic loading. The inner portions maintain sufficient thickness to preserve overall structural strength, achieving an optimal balance between stress resistance and structural integrity.
Solution Approach 2:
The reduced wall thickness in outer portions increases the local elasticity and dynamic response of the yoke arms. This allows the structure to flex and absorb bearing loads more effectively, reducing peak stresses during operation. The dynamic flexibility compensates for the reduced material thickness, maintaining adequate strength while reducing stress concentration in the critical outer regions.
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
This design significantly increases the lifespan of the universal joint yokes by reducing stress in the outer portions and increasing load absorption in the inner portions, resulting in improved bearing apparatus performance.
Implementation Method 1
The wall thickness of the yoke arms, in radial direction to the bearing axis in a plane orthogonal to the axis of rotation and through the joint center, is reduced in the outer portion relative to the inner portion... This design significantly increases the lifespan of the universal joint yokes by reducing stress in the outer portions
Data Source
AI summary
A joint yoke (7, 107) for a universal joint (2) has a first yoke arm (11, 111) and a second yoke arm (12, 112). The first and second yoke arms (11, 12) have at least two recesses (33, 33′, 34, 34′). The yoke arms (11, 12, 111, 112) have, radially to the axis of rotation (X), an outer portion (A) and an inner portion (B) adjacent to the outer portion (A). The wall thickness (d1) of the yoke arms (11, 12, 111, 112), in a radial direction to the bearing axis (Y) in a plane orthogonal to the axis of rotation (X) and through the joint center (M), is reduced in the outer portion relative to the inner portion (B).