Gearbox Hub Mechanism for Seamless Torque Direction Shifting
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Solution Overview
Problem
Conventional manual automotive gearboxes interrupt vehicle acceleration during gear changes due to the need to remove engine torque, which is undesirable in high-performance applications like sports cars, where continuous drive power is essential.
Innovation Solution
A gearbox design featuring a mainshaft assembly with drive gears and hubs that can selectively connect and disconnect based on torque direction, using engagement means and biasing forces to ensure rapid drive transmission without interrupting power, allowing gear changes without torque interruption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional manual gearbox uses a friction clutch to interrupt drive during gear changes, then the gear ratio can be changed, but vehicle acceleration is interrupted and performance is reduced
Solution Approach 1:
The patent implements continuous drive transmission during gear changes by eliminating the need for clutch interruption. The system maintains torque flow from the engine through the gearbox continuously, allowing gear ratio changes without interrupting the useful action of vehicle propulsion. This resolves the contradiction by keeping productivity (acceleration) high while still enabling adaptability (gear changes).
Solution Approach 2:
The patent introduces an intermediary mechanism - a hub with engagement means that can selectively couple with drive gears - to facilitate gear changes without requiring complete drive interruption. This intermediary allows smooth transition between gears while maintaining continuous torque transmission, thus preserving vehicle acceleration during gear changes.
2Ease of operation
If drive torque is removed from the engine to allow gear disengagement, then the sliding ring system can engage and disengage, but the rate of vehicle acceleration is reduced
Solution Approach 1:
The system maintains continuous torque transmission while enabling gear disengagement through the hub mechanism. The hub can selectively couple or decouple from drive gears without requiring complete torque removal from the engine, thus maintaining acceleration while facilitating gear changes.
Solution Approach 2:
The patent employs dynamic engagement means that can rapidly transition between engaged and disengaged states. The hub and engagement means are designed to dynamically respond to gear change commands, allowing quick gear disengagement without prolonged torque interruption, thereby maintaining high acceleration rates.
3Adaptability or versatility
If a friction clutch is used to interrupt drive power during gear changes, then gear selection can be changed, but continuous drive power is lost which is undesirable in high-performance applications
Solution Approach 1:
The patent eliminates the need for clutch-based drive interruption by implementing a hub mechanism that can change gear selections while maintaining continuous torque flow. This ensures continuous drive power is preserved during gear changes, which is critical for high-performance applications.
Solution Approach 2:
The patent extracts the clutch from the gear changing mechanism, separating the functions of torque transmission and gear selection. By removing the clutch from the gear change process, the system can change gears without interrupting drive power, thus preserving continuous power transmission while maintaining gear selection capability.
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
Enables seamless gear changes without reducing vehicle acceleration by maintaining drive power during gear shifts, improving performance in high-performance vehicles by ensuring continuous power transmission.
Implementation Method 1
the connection means including connection elements having a deployed position in which they prevent relative movement between the hub and the mainshaft and a withdrawn position in which such relative movement is allowed; in which, upon connection of both first and second hub by their respective engagement means to each corresponding drive gear, the drive connection means operates to connect one of the hubs to the mainshaft when torque is applied to the mainshaft through the hub and to connect the other one of the hubs to the mainshaft when torque is applied to the hub through the mainshaft
Data Source
AI summary
A mainshaft assembly for a gearbox includes a mainshaft (44) and drive gears (31, 36) carried for rotation about the mainshaft. First and second hubs (50, 50′) are associated with respective drive gears, each hub being operable to selectively couple or uncouple with the drive gear causing it to rotate with the hub or with respect to the hub. A drive connection mechanism (42, 64, 66) associated with each hub selectively connects the hub to the mainshaft. Upon connection of the hubs to the drive gears, the drive connection operates to connect one or other of the hubs to the mainshaft when torque is applied to the mainshaft in a first direction or an opposite direction. This enables a gear ratio to be selected by reversing the torque being handled by the gearbox.