Speed Sensitive Damping for Electronic Shifters
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Solution Overview
Problem
Shift-by-wire transmissions in vehicles lack the mechanical damping provided by traditional mechanical shift systems, resulting in a less controlled and potentially overshooting shift lever experience in electronic shifters.
Innovation Solution
A speed-sensitive damping arrangement is integrated into the electronic shifter assembly, utilizing a housing member, shaft member, stacked plates, and high shear damping grease to provide resistance to the shift lever movement proportional to its speed, mimicking the feel of mechanical shift systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a poly-stable electronic shifter is used to retain manipulated positions, then the driver's gear selection preference is improved, but overshoot and lack of damping control occurs
Solution Approach 1:
A damping arrangement with a damping member (viscous fluid or magnetorheological fluid) is introduced as an intermediary between the shift lever and the detent mechanism. This damping member provides speed-sensitive damping that controls overshoot while allowing the poly-stable feature to retain selected positions, thus resolving the contradiction between ease of operation and reliability.
2Device complexity
If shift-by-wire transmission is used to eliminate mechanical cables, then vehicle weight and complexity are reduced, but damping feedback to the driver is lost
Solution Approach 1:
The patent replaces the traditional mechanical cable-based damping system with a modern damping arrangement using viscous fluid or magnetorheological fluid. This substitution maintains the shift-by-wire simplicity while restoring damping feedback through non-mechanical means, thus resolving the contradiction between device complexity and ease of operation.
Solution Approach 2:
The damping characteristic is made variable by using magnetorheological fluid whose viscosity can be changed by applying a magnetic field. This allows the damping parameter to be adjusted dynamically, providing realistic shifting feel in different operating conditions while maintaining the simplicity of shift-by-wire architecture.
3Ease of manufacture
If conventional e-shifter arrangement is used for simplicity, then manufacturing cost is reduced, but damping feedback and shifting quality are compromised
Solution Approach 1:
Instead of making the entire e-shifter system complex, the damping function is localized to a specific damping arrangement within the shifter assembly. This localized approach maintains overall manufacturing simplicity while providing high-quality damping feedback in the critical shifting operation area, resolving the contradiction between ease of manufacture and ease of operation.
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 damping arrangement enhances the control and precision of gear selection by providing proportional resistance, reducing overshoot and offering a smoother shifting experience comparable to mechanical systems.
Implementation Method 1
The damping substance is packed into the internal cavity and about the plurality of stacked plates. The damping arrangement is configured to provide speed sensitive damping to the shift lever such that a resistance to movement of the shift lever provided by the damping arrangement is proportional to a speed of movement of the shift lever.
Implementation Method 2
The damping substance comprises high shear damping grease packed into the cavity about and between each of the stacked plates of the plurality of stacked plates.
Data Source
AI summary
An electronic shifter assembly includes a shift lever and a speed sensitive damping arrangement housed within a base of the assembly. The speed sensitive damping arrangement includes a housing, a shaft coupled to the shift lever, a plurality of stacked plates and a damping substance. The stacked plates are associated with the shaft and a cavity of the housing, where at least one of the stacked plates is keyed to the shaft and at least another one of the stacked plates is keyed to the housing such that rotation of the shaft via the shift lever causes relative movement of the keyed stacked plates. The damping substance is packed into the internal cavity and about the stacked plates such that the damping arrangement provides speed sensitive damping to the shift lever proportional to a speed of movement of the shift lever.