Automatic Transmission Control Device for Smooth Gear Shifting
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Solution Overview
Problem
Automatic transmissions with mechanical engagement mechanisms face challenges in smoothly switching between unidirectional and bidirectional rotation states, particularly when loads are applied, leading to potential abnormal sounds and vibrations during gear position changes.
Innovation Solution
A control device with a processor and sensors that detect revolution speeds and loads, enabling the mechanical engagement mechanism to switch from a bidirectional rotation preventing state to a unidirectional rotation allowing state through cooperative revolution speed control, reducing loads and improving switching smoothness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the mechanical engagement mechanism is switched from the second state (bidirectional rotation prevented) to the first state (unidirectional rotation allowed) without revolution speed control, then the gear position can be changed quickly, but abnormal sounds and vibrations occur due to load on the mechanism
Solution Approach 1:
The control device performs preliminary revolution speed control before switching the mechanical engagement mechanism from the second state to the first state. By adjusting the drive source revolution speed in advance to reduce load on the engagement mechanism, the switching can be performed smoothly without abnormal sounds or vibrations, while still maintaining efficient gear position changes
2Ease of operation
If the mechanical engagement mechanism is switched from the second state to the first state without load reduction, then the switching operation is simpler and faster, but the reliability of the mechanism decreases due to excessive load
Solution Approach 1:
The control device continuously monitors the load on the mechanical engagement mechanism by detecting revolution speeds of the drive source and input shaft. Based on this feedback information, the control device automatically adjusts the drive source revolution speed to maintain optimal loading conditions during state switching, ensuring both operational simplicity and mechanism reliability
3Object-affected harmful factors
If revolution speed control is performed before switching the mechanical engagement mechanism, then the switching smoothness is improved, but the control system complexity increases
Solution Approach 1:
The control device integrates multiple functions into a single control unit that manages both the drive source revolution speed control and the mechanical engagement mechanism state switching. This multi-functional approach achieves smooth switching without excessive control system complexity, as the same processor coordinates both speed adjustment and engagement 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
The control device ensures smooth switching of the mechanical engagement mechanism, reducing abnormal sounds and vibrations, and enhancing the reliability of gear position changes by managing loads and revolution speeds.
Implementation Method 1
an input shaft (10) to which driving force is input from a drive source (EG) via a torque converter (TC)
Data Source
AI summary
A processor is to determine, based on a first revolution speed of a drive source and a second revolution speed of an input shaft, whether or not a load toward a second direction is applied to a mechanical engagement mechanism having regulation states out of a first state in which at least one of plurality of rotating elements is rotatable only in a first direction opposite to the second direction and a second state in which the at least one of the plurality of rotating elements is not rotatable in both of the first direction and the second direction. The processor is to control the first revolution speed when the load toward the second direction is applied to the mechanical engagement mechanism to reduce the load toward the second direction, and to switch the regulation states from the second state to the first state after the first revolution speed is controlled.