Vehicle Transmission Shifting System Torque Control
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Solution Overview
Problem
Conventional shifting systems for vehicle transmissions suffer from high drag losses and rough engagement between the motor and transmission components, leading to inefficient torque transfer and an uncomfortable driving experience due to vibrations.
Innovation Solution
A shifting system with a clutch and disconnect mechanism that allows selective torque transmission through different gear ratios, utilizing a selectable one-way clutch and a shifting assembly with clutch plates to minimize drag and spin losses, ensuring smooth engagement and decoupling when necessary.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a conventional shifting system is used, then torque transfer is enabled between motor and transmission, but drag losses are high and efficiency is low
Solution Approach 1:
The shifting system is divided into separate functional components: a disconnect mechanism that segments the torque path to allow selective engagement, and a shifting assembly with multiple clutch plates that independently control gear ratio selection. This segmentation enables the system to minimize drag losses by disengaging non-active components while maintaining torque transfer efficiency through precise control of active elements.
Solution Approach 2:
The system employs dynamic engagement and disengagement of clutch plates and disconnect mechanisms to adapt torque transmission paths based on operating conditions. The disconnect can be moved between engaged and disengaged positions, and clutch plates can be selectively activated, allowing the system to optimize efficiency across different driving scenarios by dynamically adjusting which components are active.
2Adaptability or versatility
If a disconnect mechanism is used to enable shifting, then gear ratio changes are possible, but rough engagement occurs causing vibrations
Solution Approach 1:
Multiple clutch plates are introduced as intermediary elements between the input and output members of the transmission. These clutch plates provide a gradual, staged engagement mechanism that mediates the connection during gear ratio changes, allowing torque to be transferred progressively through friction rather than through sudden mechanical impact, thereby eliminating vibrations while maintaining adaptability.
Solution Approach 2:
The system changes the engagement parameter from a binary engaged/disengaged state to a multi-stage engagement process controlled by multiple clutch plates. By progressively engaging clutch plates in sequence, the system transforms the abrupt engagement into a controlled, gradual process that maintains smooth torque transfer across different gear ratios without generating harmful vibrations.
3Object-affected harmful factors
If multiple clutch plates are used for smooth engagement, then vibrations are reduced, but device complexity increases
Solution Approach 1:
The disconnect mechanism and shifting assembly are merged into an integrated system where the disconnect controls the engagement state of the clutch plates. This merging allows the complexity of multiple clutch plates to be managed through a unified control architecture, reducing the operational complexity despite the increased structural complexity of having multiple plates for smooth vibration-free engagement.
Data Source
AI summary
A method of operating a shifting system for a vehicle transmission includes engaging a clutch to operatively couple one of first and second gear ratios to an input member, and moving a disconnect from a first disconnect position where a disconnectable component is disengaged from the disconnect, to a second disconnect position where the disconnectable component is engaged with the disconnect to operatively couple the other of the first and second gear ratios to the input member through a shifting assembly. Engaging the clutch and moving the disconnect are performed such that the clutch is operatively coupled to one of the first and second gear ratios at the same time that the shifting assembly is operatively coupled to the other one of the first and second gear ratios, thus preventing torque from being transmitted through either the first and second gear ratios of the vehicle transmission to park the vehicle.