Differential Case Structure for Spider Shaft Retainer Pin Locking

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Solution Overview

Problem

Existing differential assemblies face challenges in securely retaining spider shafts and preventing axial movement of retainer pins, which can lead to instability and potential failure in torque transmission to vehicle traction wheels.

Innovation Solution

The proposed differential assembly includes a rotatable case with a first and second case portion, a spider, and a retainer pin, where the second case portion's outer mounting ring partially overlaps the retainer pin hole to inhibit removal, and weld grooves join the case portions, ensuring secure coupling of the spider shafts and retainer pins.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the retainer pin is used to couple the spider shaft to the case, then the spider shaft is retained, but the retainer pin can axially move or be removed from the retainer pin hole

Engineering Contradiction:

Improveretention of spider shaftVSAvoidaxial position of retainer pin

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The outer mounting ring acts as an intermediary component between the retainer pin and the case. It partially overlaps the retainer pin hole to inhibit axial movement of the retainer pin, while the retainer pin itself couples the spider shaft to the case. This intermediary structure resolves the contradiction by providing lateral constraint without interfering with the primary retention function.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The case is divided into a first case portion and a second case portion, with the outer mounting ring forming part of the second case portion. This segmentation allows the outer mounting ring to specifically address the axial movement issue while the first case portion maintains the primary retention function through the retainer pin hole.

Inventive Principle:

Principle #1Segmentation

2Strength

If the case portions are joined together, then the case structure is formed, but the retainer pin hole alignment and sealing may be compromised

Engineering Contradiction:

Improvecase structureVSAvoidretainer pin hole alignment

Core Design Contradiction:

StrengthVSManufacturing precision

Solution Approach 1:

The retainer pin hole is pre-formed in the first case portion before assembly with the second case portion. The outer mounting ring is then positioned to partially overlap this pre-formed hole, ensuring proper alignment is maintained during the joining process. This preliminary action prevents misalignment issues that would otherwise occur during assembly.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The outer mounting ring is positioned such that it partially overlaps and effectively 'contains' the retainer pin hole opening. This nested arrangement ensures that the hole alignment is maintained while allowing the two case portions to be joined together securely.

Inventive Principle:

Principle #7Nested doll (Nesting)

Data Source

PatentUS11231099B2Axle assembly and differential assembly with spider shaft retention

Publication Date: 2022.01.25 ARVINMERITOR TECHNOLOGY LLC

AI summary

A differential assembly that may be provided with an axle assembly. The differential assembly may have a case that may have a first case portion and a second case portion. The first case portion may have a retainer pin hole that may receive a retainer pin that couples a spider shaft to the first case portion. The second case portion may inhibit removal of the retainer pin from the retainer pin hole.