Differential Side Gear Unloading via Annular Engaging Member

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Locking differentials experience disc noise or chatter due to the disc pack in the unlocked mode, which is undesirable and needs to be addressed to reduce or eliminate this issue.

Innovation Solution

An annular engaging member is configured to unload the disc pack from the side gear while the differential is in the unlocked mode, using a Belleville washer-like structure that keeps the bell-end disc pack unloaded until axial force overcomes its resistance, preventing inadvertent clutching and associated noise.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the disc pack is engaged with the side gear in unlocked mode, then the differential allows free rotation, but disc noise (chatter) is generated

Engineering Contradiction:
Improvefree rotation capabilityVSAvoiddisc noise
Core Design Contradiction:
Ease of operationVSObject-generated harmful factors

Solution Approach 1:

A Belleville washer is introduced as an intermediary component between the disc pack and side gear. This washer acts as a mediator that separates the direct contact between these components, allowing the disc pack to remain unloaded during unlocked operation while still enabling free rotation. The washer's spring properties provide the necessary isolation to eliminate chatter noise.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the mechanical state parameter of the disc pack from engaged to unloaded during unlocked mode. By using the Belleville washer to maintain a gap or reduced contact between the disc pack and side gear, the system transitions the disc pack from a loaded state (causing noise) to an unloaded state (quiet operation) while preserving rotational freedom.

Inventive Principle:
Principle #35Parameter changes

2Object-generated harmful factors

If the disc pack is unloaded from the side gear, then disc noise is reduced, but the differential may not engage properly under load

Engineering Contradiction:
Improvedisc noiseVSAvoidengagement reliability
Core Design Contradiction:
Object-generated harmful factorsVSReliability

Solution Approach 1:

The system dynamically transitions between two states: during unlocked operation, the Belleville washer keeps the disc pack unloaded for quiet operation; when locking is required, the axial force overcomes the washer's spring resistance and engages the disc pack with the side gear. This dynamic state change ensures both quiet operation and reliable engagement as needed.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The Belleville washer is pre-configured to resist engagement between the disc pack and side gear during normal operation, preventing inadvertent clutching and noise. This preliminary counter-action is designed to be overcome only when sufficient axial force is applied during intentional locking, ensuring proper engagement reliability when required.

Inventive Principle:
Principle #9Preliminary anti-action

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 effectively reduces or eliminates disc noise (chatter) from the bell-end disc pack during the unlocked mode by ensuring the disc pack remains unloaded until necessary, enhancing operational quietness and preventing slip-stick issues.

Implementation Method 1

a Belleville washer-like structure that keeps the bell-end disc pack unloaded until axial force overcomes its resistance

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP2435729B1Locking differential side gear to friction disc unloading
Publication Date: 2014.05.07 EATON CORP
  • EP2435729B1 patent drawingFigure 1
  • EP2435729B1 patent drawingFigure 2~4

AI summary

A differential (10) is provided that includes a case (12), a cam side gear (18) disposed proximate a first end (14) of the case (12), and a side gear (20) disposed proximate a second end (16) of the case (12). The side gears (18, 20) have respective hubs (34, 36). The differential (10) further includes a first clutch pack (40) disposed around the hub (36) of the side gear (20). The differential (10) further includes an annular engaging member (62) disposed between the side gear (20) and the case (12).