Automatic Transmission Shift Arm Neutral Return Control
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Solution Overview
Problem
Existing automatic transmission devices face issues where rapid consecutive gear changes can result in poor engagement between the shift arm and shift cam, leading to incomplete gear changes due to misalignment of the start position, especially when the shift rod length is adjusted or the sensor position is deviated.
Innovation Solution
The automatic transmission device incorporates a shift actuator control system that adjusts the driving force of the shift actuator to be zero or smaller than the urging force of the spring after a gear change, ensuring the shift arm returns to the neutral position with certainty before initiating the next gear change, thereby ensuring consistent engagement with the shift cam.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the shift actuator is controlled to return to the start position after gear change, then the gear change operation is completed, but the shift arm may not return to the neutral position accurately when start position is deviated, leading to poor engagement with the shift cam
Solution Approach 1:
The control device makes the driving force zero or smaller than the urging force before the shift actuator reaches the start position, allowing the shift arm to preliminarily return to the neutral position under the spring's urging force. This preliminary action ensures accurate engagement with the shift cam's protrusion before the next gear change operation begins.
Solution Approach 2:
The control device monitors the position of the shift actuator and dynamically adjusts the driving force based on the detected position. When the shift actuator approaches the start position, the control device reduces the driving force to ensure the shift arm returns to the neutral position, creating a feedback control mechanism that compensates for position deviations.
2Ease of operation
If another gear change instruction is accepted during gear change operation, then the rider's input response is improved, but the shift arm may not be in the neutral position, causing failed engagement with the shift cam
Solution Approach 1:
The control device ensures the shift arm returns to the neutral position by making the driving force zero or smaller than the urging force before the shift actuator reaches the start position. This preliminary return action ensures the shift arm is properly positioned and engaged with the shift cam's protrusion before executing the next gear change operation, even when multiple instructions are received in quick succession.
Solution Approach 2:
The control device dynamically adjusts the driving force of the shift actuator based on real-time position feedback. When a new gear change instruction is received during operation, the control device modulates the driving force to ensure the shift arm completes its return to neutral and engages properly with the shift cam before initiating the next gear change, adapting the control strategy to the current operational state.
3Adaptability or versatility
If the shift actuator start position is deviated due to installation or maintenance variations, then the device becomes more adaptable to different conditions, but the shift arm cannot return to the correct neutral position, causing engagement failure
Solution Approach 1:
The control device makes the driving force zero or smaller than the urging force before the shift actuator reaches the preset start position, allowing the shift arm to preliminarily return to the neutral position under the spring's urging force. This preliminary action compensates for position deviations caused by installation or maintenance variations, ensuring the shift arm engages accurately with the shift cam's protrusion regardless of the actual start position.
Solution Approach 2:
The control device uses position feedback from the shift actuator to dynamically adjust the driving force. When position deviations occur due to installation or maintenance variations, the control device detects the actual position and adjusts the driving force accordingly, ensuring the shift arm returns to the correct neutral position and engages properly with the shift cam, thereby compensating for manufacturing and installation tolerances.
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
This solution ensures reliable and quick gear changes by ensuring the shift arm returns to the neutral position accurately, allowing for certain engagement with the shift cam, even with deviations in the start position or shift rod length, thereby improving the efficiency and reliability of gear changes.
Implementation Method 1
an urging member configured to urge the shift arm toward the neutral position
Data Source
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AI summary
In an automatic transmission device 40, in the case where after a first gear change instruction is output from a shift switch 8, a second gear change instruction is output by the time a shift arm 425 returns to a neutral position after moving from the neutral position to a gear position change position, a shift actuator control section 140 controls a shift actuator 72 such that a driving force of the shift actuator 72 becomes zero, after change of gear position based on the first gear change instruction is finished, and thus returns the shift arm 425 to the neutral position by the urging force of the spring 430; and then controls the shift actuator 72 such that the shift arm 425 is moved from the neutral position to the gear position change position, and thus performs change of gear position based on the second gear change instruction.