Universal Joint Retaining Member Using Polymeric Injection
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Solution Overview
Problem
Conventional universal joints face issues with dimensional variations leading to interference or excess clearance between bearing cups and snap rings, resulting in mechanical deformation, noise, or vibration, and require trial and error in assembly to achieve rotational balance.
Innovation Solution
A universal joint design featuring a spider and bifurcated yokes with apertures and circumferential grooves, where molten polymeric resin is injected to form a retaining member that couples bearing cups to the yokes, providing a secure and balanced assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If planar snap rings are used to retain bearing cups, then the bearing cups can be secured to the yoke, but dimensional variations cause interference or excess clearance leading to mechanical deformation, noise, or vibration
Solution Approach 1:
The invention changes the retention mechanism from rigid mechanical snap rings to a polymeric material that can adapt its parameters (shape, size) to match the groove geometry. The polymeric material is molded to substantially match the groove configuration, allowing it to conform to dimensional variations and eliminate clearance-induced noise and vibration while maintaining secure retention.
Solution Approach 2:
The polymeric retention member acts as an intermediary between the groove and the bearing cup. Instead of using a rigid snap ring that directly contacts both surfaces, the polymeric material fills the groove and provides a compliant interface that accommodates dimensional variations, thereby preventing the harmful effects of interference or excess clearance.
2Manufacturing precision
If multiple snap rings with different thicknesses are provided for assembly, then rotational balance can be achieved, but the assembly process requires trial and error increasing time and complexity
Solution Approach 1:
The single polymeric retention member serves multiple functions: it retains the bearing cup, provides rotational balance, and eliminates the need for multiple variants. By molding the polymeric material to substantially match the groove configuration, it inherently provides the correct thickness and shape for proper retention and balance, eliminating the need for multiple snap ring options.
Solution Approach 2:
The polymeric retention member is designed to self-adjust to the correct position and orientation through its molded geometry that substantially matches the groove configuration. During assembly, the material naturally conforms to the groove, providing automatic alignment and retention without requiring trial and error selection by the assembler.
3Reliability
If traditional snap ring retention methods are used, then bearing cups can be retained, but the number of components and manufacturing cost increase
Solution Approach 1:
The invention merges the retention function with the groove structure itself. Instead of using a separate snap ring component that sits in the groove, the polymeric retention member is molded to substantially match the groove configuration, effectively combining the groove and retention functions into a single integrated solution that reduces component count while maintaining reliable retention.
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 reduces the number of components and manufacturing costs, ensures proper alignment and balance, and simplifies the assembly process by automating the retention of bearing cups, thereby minimizing noise and vibration.
Implementation Method 1
Molten polymeric resin is injected into a groove formed in each of the arms. The groove is positioned adjacent to an associate bearing cup. The molten resin is allowed to cool to form a retaining member coupling each bearing cup to its associated arm.
Implementation Method 2
The molten resin is allowed to cool to form a retaining member coupling each bearing cup to its associated arm.
Data Source
AI summary
A universal joint includes a spider, first and second yokes drivingly interconnected by the spider, a plurality of bearing cups and a plurality of retaining members. The first yoke includes spaced apart arms with apertures extending through each arm. The apertures are coaxially aligned with one another and include a circumferential groove spaced apart from an edge of the arm. Each bearing cup is positioned within one of the apertures and in receipt of one of the trunnions. A portion of each bearing cup is positioned in communication with a corresponding groove. Each retaining member is operable to complement the size and shape of the corresponding groove, bearing cup and aperture such that each retaining member couples one of the bearing cups to its associated arm.