Automated Transmission Synchronizer Touch Point Calibration
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Solution Overview
Problem
Automatically shifting transmissions face challenges in increasing shifting speed and reducing noise due to large tolerance bands in transmission components, leading to slow and variable adaptive algorithms that are susceptible to noise factors and require time-intensive recalibration.
Innovation Solution
A method is developed to adapt transmission controls by actuating a shift drum at a constant speed, measuring feedback current, detecting spikes to determine synchronizer touch points, and adjusting the transmission controller to set synchronizer positions accurately, allowing for quick calibration and testing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If adaptive algorithms are used to account for transmission tolerances, then synchronizer touch point positioning is improved, but calibration time increases and variability increases
Solution Approach 1:
The patent replaces complex adaptive software algorithms with a direct electrical measurement approach. By measuring feedback current spikes from the shift drum motor during controlled movement, the system directly determines synchronizer touch points without requiring iterative adaptive routines, thereby reducing calibration time while maintaining positioning accuracy
Solution Approach 2:
The system uses its own existing components (shift drum motor, feedback current measurement capability) to automatically determine touch points. The calibration process leverages the motor's own electrical characteristics during operation to identify synchronizer engagement points, eliminating the need for external calibration equipment or time-intensive procedures
2Measurement precision
If adaptive algorithms are used to account for transmission tolerances, then synchronizer touch point positioning is improved, but algorithm variability increases
Solution Approach 1:
The patent replaces variable adaptive algorithms with a deterministic electrical measurement method. The feedback current spike detection provides consistent, repeatable results based on physical electrical characteristics rather than software-based inference, eliminating algorithmic variability and improving result stability
Solution Approach 2:
The system uses real-time feedback current measurement during shift drum movement to directly detect synchronizer engagement. This closed-loop electrical feedback provides stable and consistent touch point identification by relying on measurable electrical signatures rather than probabilistic algorithmic predictions
3Device complexity
If traditional tolerance stack-up methods are used, then design simplicity is maintained, but shifting speed increases are limited and noise decreases are limited
Solution Approach 1:
The patent changes the approach from using fixed tolerance parameters in design to dynamically determining actual touch points through electrical measurement. This allows the system to achieve precise synchronizer engagement timing without increasing mechanical tolerance requirements, thereby enabling faster shifting while maintaining design simplicity
Solution Approach 2:
The system performs quick calibration to determine exact touch points before normal operation. By pre-establishing accurate touch point positions through feedback current measurement, the transmission can execute faster shifts with precise timing, improving shifting speed without complicating the overall design
4Device complexity
If traditional tolerance stack-up methods are used, then design simplicity is maintained, but transmission noise decreases are limited
Solution Approach 1:
The patent changes from fixed tolerance-based timing to dynamically measured touch point positions. This enables precise control of synchronizer engagement timing, allowing optimization of shift characteristics to minimize noise while keeping the mechanical design simple
Solution Approach 2:
By pre-calibrating exact touch points using feedback current measurement, the system can optimize synchronizer engagement timing to reduce noise. This preliminary action establishes accurate reference points that enable noise-minimizing shift execution without increasing design complexity
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 method enables rapid and accurate calibration of synchronizer locations, improving shifting speed and reducing noise by accounting for transmission tolerances, and can be applied at the end of the assembly line or after extensive use to account for wear.
Implementation Method 1
measuring a feedback current as the motor moves the shift drum
Data Source
AI summary
A method of adapting transmission controls to locate synchronizer touch points in an automated layshaft transmission. This method may include actuating a motor to move a shift drum along a layshaft at an essentially constant speed; measuring a feedback current as the motor moves the shift drum; detecting a first spike in feedback current adjacent to a second spike in feedback current for a gear; determining a shift drum angle for the first spike; and adjusting a transmission controller to set a synchronizer touch point at a shift drum angle adjacent to the first feedback current spike for the gear.