Differential Thrust Washer Locking to Prevent Housing Wear

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Solution Overview

Problem

Conventional thrust washers in differentials experience wear and failure due to high forces and contamination, leading to housing malfunction, as they either rotate relative to the housing or have locking mechanisms that cause stress concentrations and friction increases.

Innovation Solution

A thrust washer design with an annular shape and engagement mechanisms, such as indentations or apertures, that lock to spider arms to prevent rotation relative to the housing, reducing wear by distributing torque forces and allowing debris flow through gaps.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-generated harmful factors

If conventional thrust washers are designed to rotate relative to the housing, then friction is reduced, but wear increases due to contamination and fluid film issues

Engineering Contradiction:
ImprovefrictionVSAvoidwear resistance
Core Design Contradiction:
Object-generated harmful factorsVSReliability

Solution Approach 1:

The thrust washer is divided into multiple segments or pieces that are arranged circumferentially. These segments can move independently relative to each other, allowing them to accommodate housing wear and contamination while maintaining low friction. The segmented design enables the washer to adapt to irregularities in the housing surface without requiring a complete rotation, thus reducing wear while maintaining low friction characteristics.

Inventive Principle:
Principle #1Segmentation

2Reliability

If locking tabs are added to prevent washer rotation, then wear is reduced, but stress concentrations and friction increase causing tab fracture

Engineering Contradiction:
Improvewear resistanceVSAvoidstress resistance
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The invention removes the locking tabs entirely from the thrust washer design. Instead of using tabs that lock the washer to the housing, the design relies on the segmented structure and friction between segments to prevent rotation. This extraction of the locking tab element eliminates the stress concentration points and potential fracture locations while still achieving the goal of preventing washer rotation and reducing wear.

Inventive Principle:
Principle #2Taking out (Extraction)

3Ease of manufacture

If the housing is made from softer material for manufacturability, then ease of manufacture improves, but wear resistance decreases under sliding action

Engineering Contradiction:
ImprovemanufacturabilityVSAvoidwear resistance
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The segmented thrust washer acts as an intermediary element between the softer housing and the spider gear. The multiple segments can adapt to the housing surface and distribute loads more evenly, reducing localized wear on the softer housing material. The segmented structure allows the washer to compensate for the lower wear resistance of the softer housing material while maintaining overall system reliability.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 design effectively prevents washer and housing wear by stabilizing the thrust washer, reducing friction, and facilitating debris removal, thereby enhancing differential longevity and reliability.

Implementation Method 1

configured to engage with the spider to prevent or reduce the thrust washer from rotating relative to the housing

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

engagement mechanisms, such as indentations or apertures, that lock to spider arms to prevent rotation relative to the housing

Methodology Applied
Scientific EffectMechanical Fastening: Mechanical Fastener

Implementation Method 3

allowing debris flow through gaps

Methodology Applied
Scientific EffectGravity-driven flow: Gravitation

Data Source

PatentEP3914830B1Differential and thrust washer therefor
Publication Date: 2025.10.29 TIGERCAT IND
  • EP3914830B1 patent drawingFigure 1A~1D
  • EP3914830B1 patent drawingFigure 2
  • EP3914830B1 patent drawingFigure 3

AI summary

A thrust washer and a differential containing a thrust washer. The differential has a housing, a spider and one or more spider gears. The thrust washer includes a body having an annular shape and a width configured to approximately match with a width of the one or more spider gears. The thrust washer is further configured to engage with the spider to prevent or reduce the thrust washer from rotating relative to the housing when the thrust washer is installed in the differential.