Axle Shift Collar Positioning for Towing and Limp-Home Modes
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Solution Overview
Problem
Existing axle assemblies with electric motor modules lack a reliable mechanism to securely position the shift collar in desired gear ratios, particularly during towing or limp home modes, leading to potential unintended gear engagement and inefficiencies.
Innovation Solution
A positioning mechanism is installed in place of the actuator to hold the shift collar in a desired position, utilizing a mounting plate and shaft that engage with the cam's mounting feature, ensuring secure positioning and preventing unwanted shifts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an actuator is used to move the shift collar, then the shift mechanism can be actuated, but the mechanism lacks reliability in maintaining desired gear ratios during towing or limp home modes
Solution Approach 1:
The positioning mechanism is segmented into distinct functional components: a mounting plate for attachment, a shaft for engagement with the cam, and a locking feature for securing the shift collar. This segmentation allows each component to perform its specific function reliably while keeping the overall mechanism simple and maintainable.
Solution Approach 2:
The positioning mechanism acts as an intermediary device between the actuator and the shift collar. It provides a reliable intermediate stage that secures the shift collar in the desired position, ensuring gear ratio maintenance during towing or limp home modes without requiring complex active control systems.
2Ease of manufacture
If the shift collar is left unsecured, then the mechanism remains simple, but unintended gear engagement occurs leading to inefficiencies
Solution Approach 1:
The positioning mechanism is designed to be self-securing through its locking feature that automatically engages with the cam at the desired position. Once the shift collar is moved to the neutral position, the locking feature passively maintains this position without requiring continuous active control or additional energy input, thus preventing unintended gear engagement and reducing energy loss.
3Stability of the object's composition
If a positioning mechanism is added to secure the shift collar, then gear position stability is improved, but the device complexity increases
Solution Approach 1:
The positioning mechanism applies local quality by concentrating the stabilization function at the specific location where the shift collar engages with the cam. The locking feature is positioned precisely to engage with the cam's mounting feature, providing stable gear position maintenance only where needed, rather than complicating the entire shift mechanism.
Solution Approach 2:
The positioning mechanism performs preliminary action by pre-positioning and pre-locking the shift collar in the desired neutral position before any unintended gear engagement can occur. The locking feature is designed to engage automatically when the shift collar reaches the desired position, ensuring stability is established in advance.
Data Source
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AI summary
A method of controlling an axle assembly. The method may include removing an actuator that is adapted to actuate a shift collar from a housing of the axle assembly, installing a positioning mechanism in place of the actuator, and securing the positioning mechanism to the housing of the axle assembly.