Selector Drum Transmission Blocking Adverse Torque Shifts
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Solution Overview
Problem
Existing transmission systems face issues with inappropriate gear shifts during certain torque conditions, leading to engine over-speed or inappropriate upshifts/downshifts, particularly in manually operated gearboxes, due to the inability to prevent pre-selection of multiple gear changes.
Innovation Solution
A transmission system with a selector drum and biasing mechanism that blocks upshifts in negative torque conditions and downshifts in positive torque conditions by using angled blocking features that engage to prevent rotation when adverse torque conditions are present, allowing gear transitions only when torque conditions are reversed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If pre-selection of gear is allowed in manually operated gearbox, then ease of operation is improved, but engine over-speed occurs
Solution Approach 1:
The transmission system applies preliminary anti-action by implementing blocking features that prevent pre-selection of multiple gear changes before the engine is ready. The blocking mechanism proactively stops the selector drum from rotating into positions that would cause inappropriate gear shifts, thereby preventing engine over-speed before it occurs.
Solution Approach 2:
The blocking feature acts as an intermediary between the selector drum and the gear selection mechanism. It mediates the gear selection process by allowing rotation only when torque conditions are favorable, blocking the path when conditions are adverse, thus preventing engine over-speed while maintaining ease of operation.
2Reliability
If blocking features are added to prevent inappropriate gear shifts, then reliability is improved, but device complexity increases
Solution Approach 1:
The blocking feature is merged with the existing selector drum mechanism. The blocking feature integrates with the torque sensing capability already present in the transmission system, combining the gear selection function with the blocking function in a unified structure that prevents inappropriate shifts without adding separate complex control systems.
Solution Approach 2:
The blocking feature operates autonomously based on torque conditions detected within the transmission system. It self-activates when adverse torque conditions are detected and self-deactivates when conditions become favorable, eliminating the need for external control systems or additional complexity in the gear selection process.
3Reliability
If blocking mechanism is implemented, then inappropriate gear shifts are prevented, but ease of operation is reduced
Solution Approach 1:
The blocking mechanism operates automatically based on torque conditions without requiring driver intervention. The system self-regulates the gear selection process by blocking rotations during adverse torque conditions and automatically allowing rotations when conditions become favorable, maintaining ease of operation while preventing inappropriate shifts.
Solution Approach 2:
The blocking feature incorporates feedback from the torque conditions within the transmission system. It continuously monitors torque direction and magnitude, using this feedback to dynamically adjust whether gear selection is blocked or allowed, ensuring reliable operation while maintaining user-friendly control.
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
Prevents inappropriate gear shifts by blocking transitions during adverse torque conditions and allowing smooth transitions when torque conditions are favorable, thereby preventing engine over-speed and ensuring appropriate gear changes.
Implementation Method 1
a biasing mechanism for urging the selector drum towards a rest position along the length of the shaft
Data Source
Figure 1
Figure 2
Figure 3a~3f
AI summary
A transmission having a torque input and a torque output, a plurality of drive members that are selectively engagable for sequentially changing gear ratio between the torque input and the torque output, the transmission also having a shaft provided with at least one shifting feature each of which comprises: a drum having a track at least partially around its outer perimeter and arranged such that torque can be transferred thereto by rotating the shaft, the drum also capable of being moved along the length of the shaft; a biasing mechanism for urging the drum towards a rest position along the length of the shaft; and a drive member selector member provided in operative relation to said track, wherein by rotating the shaft the drive member selector member can be selectively urged into contact with a first said drive member for drivingly engaging therewith in a first torque connection or into contact with a second said drive member for drivingly engaging therewith in a second torque connection, the first and second torque connections being in opposite directions; wherein each respective said shifting feature is configured such that when the drive member selector member thereof is drivingly engaged with a said drive member in either a positive or negative torque condition of the transmission in use, rotation of the shaft is blocked in one direction whereby a blocking condition occurs part way between an initial rotational position of the shaft and a rotational position in which the next sequentially selectable gear ratio would be caused to be engaged if the torque condition of the transmission was reversed.