Automatic Transmission Control Device Preload Shift
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Solution Overview
Problem
Existing automatic transmission control devices experience prolonged shift transmission times and increased vibrations due to delayed torque balance detection and temporally-deviated clutch and shift disengagement operations, leading to reduced mileage and operability, especially during acceleration or deceleration.
Innovation Solution
A control device for automatic transmission that applies a preload to the synchromesh mechanism upon shift request detection, followed by a higher shift load to gradually release coupling, reducing torsional vibrations and shortening shift change time by controlling the preload and shift loads through a preload control unit and shift control unit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the shift disengagement operation starts immediately at the time of releasing the automatic clutch, then the shift transmission time is shortened, but torsional vibration occurs in the rotary shafts due to increased meshing force of the gear pairs
Solution Approach 1:
The patent applies a preliminary action by performing a clutch release operation before the shift disengagement operation. The control device releases the automatic clutch to reduce torque transmission to a predetermined level before initiating the shift disengagement of the synchromesh mechanism. This preliminary clutch release reduces the meshing force between gear pairs, preventing torsional vibrations while enabling timely shift transmission. The clutch release stroke is controlled to achieve the desired torque reduction without completing the full release, creating optimal conditions for subsequent shift operation.
2Object-affected harmful factors
If the starting time of shift disengagement is set based on torque balance timing, then torsional vibration is suppressed, but the shift transmission time is prolonged due to late torque balance
Solution Approach 1:
Instead of waiting for torque balance to occur naturally (which delays the shift operation), the patent performs a preliminary clutch release action to proactively reduce the torque transmission level before shift disengagement is needed. This preliminary action creates the favorable torque condition in advance, allowing the shift operation to start at the optimal time without waiting for natural torque balance, thus preventing vibrations while maintaining rapid shift transmission.
Solution Approach 2:
The control device uses feedback by monitoring the clutch release stroke amount to determine when to initiate the shift disengagement operation. The control unit detects when the clutch release stroke reaches a predetermined value, indicating that torque transmission has been reduced to the appropriate level. This feedback mechanism enables precise timing control, ensuring shift disengagement starts at the optimal moment when meshing force is sufficiently reduced, preventing vibrations while minimizing shift transmission time.
3Object-affected harmful factors
If the clutch release operation and shift disengagement operation are performed with temporal deviation, then vibration is reduced, but the shift transmission time is prolonged
Solution Approach 1:
The patent implements a structured preliminary action sequence where the clutch release operation is initiated first and progressed to a predetermined stroke amount before the shift disengagement operation begins. This controlled temporal sequence ensures that the clutch release prepares the system by reducing torque transmission, creating optimal conditions for the subsequent shift operation. The predetermined stroke amount serves as a trigger point, ensuring the preliminary action is completed just in time to enable immediate shift disengagement without unnecessary delay.
Data Source
AI summary
There is provided a control device for an automatic transmission configured to automatically shift a transmission of a driving force of a motor in response to a driving state. The automatic transmission includes a synchromesh mechanism configured to couple gear pairs and a rotary shaft to transmit the driving force of the motor to the gear pairs and a switching apparatus configured to switch a coupling state of the gear pairs and the rotary shaft. A preload control unit is configured to operate the switching apparatus to apply a preload to the synchromesh mechanism when a shift transmission request is detected. A shift control unit is configured to operate the switching apparatus to apply a shift load greater than the preload to the synchromesh mechanism after the preload is applied to the synchromesh mechanism.