Torque Limiting Differential Shear Pins
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Solution Overview
Problem
Vehicle axles fail due to excessive torque when differential is locked, leading to potential damage to axle components and the differential itself, as existing designs do not effectively manage high torque without compromising axle integrity.
Innovation Solution
A selectively lockable differential with torque-sensitive pins and a collar system that shears before the axle fails, allowing the differential to revert to open mode and prevent further damage, featuring a collar with collar teeth and torque-sensitive pins that engage and disengage gear lugs to manage torque.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the differential is fully locked to transmit 100% of torque on the ring gear, then torque transmission capability is improved, but the axle shaft may fail due to excessive torque
Solution Approach 1:
The torque sensitive pins act as intermediary components between the locking collar and the case, designed to fail at a predetermined torque threshold. These pins transmit torque from the locking collar to the case while protecting the axle shaft by shearing before the axle can fail, thus serving as a protective mediator in the torque transmission path
Solution Approach 2:
The torque sensitive pins are designed as sacrificial, disposable components with lower strength than the axle shaft. When excessive torque is applied, these pins shear off intentionally, allowing the locking collar to disengage and preventing more expensive and critical components like the axle shaft from failing. The pins are replaceable and their failure is an intended protective mechanism
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 solution effectively limits torque to prevent axle failure and subsequent damage, ensuring the vehicle remains operational by shearing the torque-sensitive pins before the axle shaft fails, thus preserving axle integrity and preventing collateral damage.
Implementation Method 1
a plurality of torque sensitive pins... The torque sensitive pins may be positioned to couple the locking collar to the case... Before the locking collar is able to rotate with the case, the torque sensitive pins may shear
Data Source
AI summary
A selectively lockable differential, comprising a plurality of torque sensitive pins, an outer housing, a first side gear comprising first gear teeth, a second side gear comprising second gear teeth, a pinion shaft, two pinion gears rotationally coupled to the pinion shaft, each pinion gear comprising pinion gear teeth coupled to the first gear teeth and the second gear teeth, and a collar comprising collar teeth for selectively engaging the gear lugs of the first side gear, the torque sensitive pins operatively coupling the collar to the outer housing.