Universal Joint Yoke Mounting Assembly Axial Retention
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Solution Overview
Problem
Existing mounting assemblies for drive shafts in universal joints suffer from non-homogeneous load distribution and premature fatigue wear due to the deformation of circumferential or helical fins, which compromises the mechanical strength and durability of the assembly.
Innovation Solution
A mounting assembly featuring a clamp bolt with a threaded and non-threaded cylindrical stem, where the non-threaded portion expands to increase the sleeve's outer dimensions, providing axial retention of the drive shaft and distributing pressure evenly, while a third cylindrical portion enhances the bolt's seat in the yoke, preventing fatigue wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If circumferential or helical fins are deformed to retain the driving shaft, then axial movement is prevented, but load distribution becomes non-homogeneous and fatigue wear increases
Solution Approach 1:
The bolt stem is segmented into three distinct cylindrical portions: a first threaded portion for fastening, a second non-threaded portion with intermediate diameter for sleeve expansion, and a third non-threaded portion with larger diameter for yoke support. This segmentation allows each portion to perform its specific function optimally, preventing both fatigue wear in the yoke and non-homogeneous loading on the shaft.
Solution Approach 2:
Different portions of the bolt stem have different diameters and functions: the first portion threads into the yoke, the second portion expands the sleeve to create uniform radial pressure on the shaft, and the third portion provides a large-bearing surface seat in the yoke. This local differentiation of properties ensures homogeneous load distribution and prevents fatigue wear at critical locations.
2Reliability
If the sleeve covers the whole bolt stem to retain the shaft, then axial movement is prevented, but the sleeve undergoes premature fatigue wear due to insufficient mechanical strength
Solution Approach 1:
The bolt stem is divided into functional segments where the third cylindrical portion with larger diameter serves as a dedicated support seat in the yoke, bearing the mechanical load and preventing fatigue wear of the sleeve. The sleeve only needs to cover the critical retention portion, not the entire stem, reducing its exposure to fatigue conditions.
Solution Approach 2:
The third cylindrical portion of the bolt stem acts as an intermediary bearing surface between the yoke and the sleeve. It provides a robust mechanical seat that distributes loads away from the sleeve material, preventing premature fatigue wear while maintaining axial retention functionality.
3Ease of manufacture
If the bolt stem is uniformly threaded along its length, then fastening is simplified, but the sleeve cannot be properly expanded to increase outer dimensions for axial blocking
Solution Approach 1:
The bolt stem is segmented with the middle portion being non-threaded with an intermediate diameter, allowing the sleeve to be inserted and expanded over this section. The expansion of the sleeve over the non-threaded portion creates the necessary increase in outer dimensions to axially block and retain the driving shaft, while the threaded portions at the ends provide fastening capability.
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 ensures a consistent and durable clamping force, preventing axial movement of the drive shaft and reducing material fatigue, thereby improving the assembly's effectiveness and longevity.
Implementation Method 1
the non-threaded portion expands to increase the sleeve's outer dimensions
Implementation Method 2
the sleeve exerts a pressure on the surface of said driving shaft preventing it from being axially moved
Data Source
AI summary
A mounting assembly for a universal joint that includes a yoke with wings between which a driving shaft is provided. The wings have respective holes. A bolt having a head and a stem is transversely to the wings. A sleeve receives the stem of the bolt so that, in an assembled position, the sleeve exerts a pressure on a surface of the driving shaft preventing its axial movement, wherein the stem has at least a first, threaded end portion, a second, non-threaded adjacent portion, and a third portion. The diameter of the second portion is slightly larger than an inner diameter of the sleeve. The third portion has a diameter slightly larger than the second portion. When the bolt is inserted into the sleeve, the sleeve expands resulting in an increase of its outer dimensions against the surface of the driving shaft blocking it axially in position as it is pressed against the yoke. The third portion of the bolt is received in one of the holes, thereby seating the bolt with respect to the yoke.