Elastomeric Cross Pin Retainer for Differential Assembly
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Solution Overview
Problem
Existing methods for securing the cross pin in differential assemblies require costly machining operations and time-consuming torquing processes, and do not allow for convenient removal during assembly, increasing manufacturing time and cost.
Innovation Solution
A cross pin retainer made of semi-compliant material that can be positioned in two states: partially-inserted for easy removal and fully-inserted for secure retention, eliminating the need for costly machining and allowing for simpler assembly by elastically deforming to engage with the differential housing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If threaded fasteners or roll-pins are used to secure the cross pin, then the cross pin is retained in the differential housing, but costly machining operations and time-consuming torquing processes are required
Solution Approach 1:
The patent changes the physical state and material properties of the retainer from rigid to elastomeric, allowing it to deform elastically during installation and then maintain retention through elastic recovery. This eliminates the need for threaded fasteners and complex machining operations while ensuring reliable cross pin retention.
Solution Approach 2:
The elastomeric retainer is designed as a simple, inexpensive component that can be easily replaced if needed, eliminating the need for expensive machining operations on the differential housing and cross pin. The retainer itself becomes the sacrificial element rather than requiring permanent modifications to other components.
2Reliability
If threaded fasteners are used to secure the cross pin, then the cross pin is retained, but a costly and time-consuming torquing operation is required
Solution Approach 1:
The patent replaces the mechanical fastening system (threaded fasteners requiring torquing operations) with an elastomeric retention system that uses elastic deformation and recovery. This substitution eliminates the need for torquing tools and operations, significantly reducing assembly time while maintaining reliable retention.
3Reliability
If conventional retention mechanisms are used, then the cross pin is secured, but convenient removal of the cross pin during assembly is not permitted
Solution Approach 1:
The elastomeric retainer provides dynamic retention that adapts to installation and removal needs. During installation, the retainer deforms to allow cross pin insertion, then elastic recovery provides secure retention. During removal, the retainer can be easily deformed again to release the cross pin, providing convenient disassembly while maintaining reliable operation during use.
4Reliability
If snap rings are positioned in grooves to secure the cross pin, then retention is achieved, but costly machining operations are required to form the grooves
Solution Approach 1:
The elastomeric retainer replaces the need for expensive groove machining by using a simple, inexpensive component that can be installed in a standard bore. The retainer itself performs the retention function that would otherwise require precision-machined grooves and snap rings, significantly reducing manufacturing cost.
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 solution reduces manufacturing costs and time by eliminating the need for complex retention mechanisms, enabling faster assembly and disassembly of differential assemblies while maintaining structural integrity.
Implementation Method 1
When located in its partially-inserted position, a portion of the cross pin retainer elastically deforms and snugly engages a retention bore formed in the differential housing
Implementation Method 2
When located in its fully-inserted position, a portion of the cross pin retainer expands to engage a wall in the differential housing to restrict subsequent retraction of the cross pin retainer
Data Source
AI summary
A differential assembly includes a retainer for a cross pin having a bore aligned with a bore formed in a differential housing. The cross pin retainer is positionable at partially-inserted and fully-inserted positions within the cross pin and differential bores. At a first rotational orientation, the cross pin retainer is positionable in its partially-inserted position to temporarily retain the cross pin within the differential housing. At a second rotational orientation, the cross pin retainer is positionable in its fully-inserted position to retain the cross pin within the differential housing. Features of the cross pin retainer cooperate with surfaces formed in the differential housing to allow the cross pin retainer to be fixedly positioned and secured within the differential housing.