Locking Differential Sleeve Mechanism for Bevel Gear Load Relief

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Solution Overview

Problem

Locking differentials face issues with excessive torque loads during off-roading, leading to potential gear failure due to high loads on side bevel gears, which can result in immobility of vehicles.

Innovation Solution

A locking differential design that allows free rotation of bevel gears in the unlocked configuration and locks them to the carrier in the locked configuration, using a movable sleeve with external and internal teeth engaging with splines on the carrier to prevent relative movement, thereby reducing the load on the gear teeth.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a locking differential is provided in a motor vehicle to allow different wheel speeds during cornering while maintaining traction, then wheel slip is reduced and handling is improved, but the device complexity increases due to additional mechanical components

Engineering Contradiction:
Improvetraction maintenanceVSAvoidmechanical components
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the locking mechanism and differential function into a single integrated unit. The locking differential assembly merges the differential gear mechanism with a locking mechanism that can lock the differential when slip is detected, eliminating the need for separate differential and locking devices while maintaining both functions.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The locking differential employs dynamic elements including a cam mechanism that automatically adjusts locking intensity based on wheel slip conditions, and a control system that dynamically engages or disengages the locking function according to real-time driving conditions, allowing the device to adapt its behavior rather than remaining static.

Inventive Principle:
Principle #15Dynamics

2Reliability

If a locking mechanism is added to prevent wheel slip during acceleration, then traction is improved, but the ease of operation deteriorates due to automatic engagement without driver control

Engineering Contradiction:
Improvewheel slip preventionVSAvoiddriver control
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The locking differential is designed to automatically detect wheel slip conditions and engage the locking mechanism without driver intervention. Sensors monitor wheel speed differences and automatically activate the locking function when slip is detected, allowing the system to serve itself by making its own operational decisions based on real-time conditions.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system incorporates feedback mechanisms where sensors continuously monitor wheel speed and provide information to the control system. The control system processes this feedback and automatically adjusts the locking mechanism engagement level, creating a closed-loop control system that responds to actual driving conditions rather than requiring open-loop driver commands.

Inventive Principle:
Principle #23Feedback

3Reliability

If the locking mechanism is designed to be always engaged, then maximum traction is maintained, but the loss of energy increases due to restricted wheel speed differentiation

Engineering Contradiction:
ImprovetractionVSAvoidenergy efficiency
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The locking mechanism is designed to be dynamic rather than static, automatically adjusting its engagement level based on real-time wheel slip detection. When no slip is detected, the locking mechanism disengages to allow free wheel speed differentiation for energy efficiency. When slip is detected, the locking mechanism engages to the extent necessary to prevent slip, thereby optimizing the balance between traction and energy consumption.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The locking mechanism operates in periodic cycles of engagement and disengagement based on detected wheel slip conditions. Rather than remaining constantly engaged, the system periodically monitors wheel speeds and engages the locking mechanism only during periods when slip is detected, allowing energy-efficient operation during normal conditions while providing traction assistance when needed.

Inventive Principle:
Principle #19Periodic action

Data Source

PatentEP3679277B1Locking differential
Publication Date: 2023.05.24 ROBERTS ANTHONY DAVID
  • EP3679277B1 patent drawingFigure 1
  • EP3679277B1 patent drawingFigure 2A~2C
  • EP3679277B1 patent drawingFigure 3A~3D

AI summary

The description is directed broadly to a locking differential, comprising; a pair of rotating bevel gears engaged with one another via at least one pinion gear rotatably supported within a carrier; a locking member disposed within the carrier and engagable with each of the bevel gears, the locking member being movable between a locked configuration and an unlocked configuration, such that in the unlocked configuration the locking member allows free rotation of the bevel gears in engagement with the at least one pinion gear to equalise torque between a first bevel gear and a second bevel gear of the pair, and in the locked configuration the locking member locks the first bevel gear to the carrier and locks the second bevel gear to the carrier, simultaneously, to prevent relative movement therebetween.