Motor-Driven Shift Drum Control for Low-Impact Gear Changes
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Solution Overview
Problem
Conventional variable-speed transmissions with electric-motor-driven shift drums experience material wear and unreliable gear changes due to abrupt synchronization and high mechanical loads, particularly in dog ring transmissions, which require quick shift operations to minimize impact and wear.
Innovation Solution
A method for controlling a variable-speed transmission using an electric-motor direct drive for the shift drum, incorporating a brushless DC motor or torque motor with precise control, eliminating the need for gear position sensors and reducing mechanical loads by calculating rotational energies and implementing field-oriented control to optimize torque and power factor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If quick shift operations are performed in dog ring transmissions to minimize impact and wear, then shift speed is improved, but mechanical loads and material wear increase during the shifting process
Solution Approach 1:
The control system performs preliminary actions by detecting the start of a shifting operation and pre-reducing the drive torque before the actual gear engagement occurs. This preparatory torque reduction prevents excessive mechanical loads and material wear during the shifting process while maintaining quick shift speed.
Solution Approach 2:
The system continuously monitors shift operation status and provides feedback to the control unit, which adjusts the drive torque in real-time. This feedback mechanism ensures that torque is reduced during shifting operations and restored after completion, optimizing both shift speed and reducing mechanical wear.
2Object-affected harmful factors
If drive torque is reduced during shifting operations to minimize mechanical loads, then material wear is reduced, but shift performance and reliability may deteriorate
Solution Approach 1:
The control system applies periodic torque adjustment: reducing torque during the shifting operation and restoring it after completion. This periodic action pattern ensures that material wear is minimized during shifting while shift performance and reliability are maintained through proper torque management at different phases of the operation.
Solution Approach 2:
The system dynamically adjusts drive torque based on the real-time status of shifting operations. By making torque variable rather than constant, the system optimizes both material wear reduction during shifting and shift performance through appropriate torque levels at different operational phases.
3Device complexity
If conventional electric motors are used for shift drum actuation, then device complexity is reduced, but precision control and reduction of mechanical loads are compromised
Solution Approach 1:
The control system changes operational parameters by dynamically adjusting drive torque based on shifting operation status. This parameter change enables precise control of the shift drum actuation, improving shift control precision while managing mechanical loads without requiring fundamentally different motor technology.
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
Enables precise, reliable, and low-wear gear changes with reduced impact and pulse loads, minimizing mechanical stress and improving shift performance by preventing overshoots and undershoots through advanced control algorithms.
Implementation Method 1
incorporating a brushless DC motor or torque motor with precise control
Implementation Method 2
implementing field-oriented control to optimize torque and power factor
Data Source
AI summary
Disclosed is a torque-converting or speed-converting variable-speed transmission with at least two gear ratios. Each gear ratios is assigned at least one changeable gear pair. Shifting elements act on sliding sleeves (24) connected to the gear pairs to change these gear pairs. The shifting elements are in engagement with a shift drum (10), which is moveable into defined angular positions and rotatable between these angular positions. The shift drum (10) has an electric-motor direct drive (12), which can rotate it and bring it into the particular defined angular positions. A method used to control such a torque-converting or speed-converting variable-speed transmission is also contemplated.