Segmented Locking Differential Collar for High Torque

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Solution Overview

Problem

Conventional locking differentials have a limited torque capacity due to restricted axial travel of the locking mechanism, resulting in a low engagement length, which is insufficient for effective traction modification in various operational conditions.

Innovation Solution

The design incorporates a collar-style locking differential with radially outward and inward-extending locking members, segmented to allow minimal axial movement for locking and unlocking, enabling a high engagement length while maintaining a low stroke length, facilitated by an actuator and electromagnetic coil for controlled operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of moving object

If conventional locking mechanisms are used with limited axial travel, then the device complexity is reduced, but the engagement length is insufficient for effective traction modification

Engineering Contradiction:
Improveengagement lengthVSAvoidlocking mechanism complexity
Core Design Contradiction:
Length of moving objectVSDevice complexity

Solution Approach 1:

The locking members are divided into multiple segments with grooves between them, allowing the collar to move through discrete positions. This segmentation enables the locking mechanism to achieve a longer effective engagement length through multiple engagement points while maintaining a compact overall structure with limited axial travel.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The locking members extend radially inward and outward from the collar and side gear respectively, creating engagement in the radial dimension rather than relying solely on axial travel. This dimensional change allows the mechanism to achieve sufficient engagement length without requiring excessive axial stroke.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Ease of manufacture

If the locking members are made as single continuous pieces, then the manufacturing is simpler, but the axial travel required for locking is increased

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidaxial travel
Core Design Contradiction:
Ease of manufactureVSLength of moving object

Solution Approach 1:

The locking members are segmented into discrete sections separated by grooves, which reduces the axial travel required for engagement to merely the thickness of one segment. While this increases manufacturing complexity compared to continuous pieces, it dramatically reduces the stroke length and enables a more compact design.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP2855977B1Low stroke length locking differential with high locking engagement length
Publication Date: 2018.01.10 EATON CORP
  • EP2855977B1 patent drawingFigure 1
  • EP2855977B1 patent drawingFigure 2
  • EP2855977B1 patent drawingFigure 3

AI summary

A differential, comprising a gear case, a side gear, an actuator, and a collar. The gear case comprising a central axis and recesses. The side gear configured to rotate around the central axis. The side gear comprising radially outward-extending locking members comprising side gear segments separated by plural grooves. The actuator surrounding the central axis. The collar configured to translate bi-directionally along the central axis. The collar comprising ears and radially inward-extending locking members comprising collar segments separated by plural grooves. The actuator is configured to move the collar relative to the side gear to move the ears axially in the recesses. When the actuator moves the collar to a locked position, the collar segments are configured to engage the side gear segments. When the actuator moves the collar to an unlocked position, the side gear segments are configured to pass through the grooves of the radially inward-extending locking members.