Shift Position Detection Device for Two-Speed Transmission
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Solution Overview
Problem
Existing shift position detection devices for mechanical two-speed manual transmissions, particularly standstill transmissions, face challenges in reliably and clearly detecting shift positions during gear changes while driving, leading to potential errors in electrohydraulic speed synchronization.
Innovation Solution
A shift position detection device with two sensors interacting with three shift ramps, where only one sensor changes its state at a time, allowing for clear monitoring of shift states and positions through a specific stroke range, and an electronic control device determines the correct sequence of sensor states to prevent errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If two sensors are used to detect shift positions in a mechanical two-speed manual transmission, then the reliability of shift position detection is improved, but the device complexity increases
Solution Approach 1:
The detection function is segmented between two sensors (S1, S2) that independently monitor different aspects of shift position. Each sensor detects specific shift ramp positions, and their combined signals provide comprehensive shift state information, improving reliability through distributed detection while maintaining manageable complexity
Solution Approach 2:
The system implements feedback through the electronic control device that continuously monitors the states of both sensors and uses this information to verify shift positions and detect errors. The feedback mechanism compares expected sensor states with actual states, enabling reliable detection while managing complexity through intelligent signal processing
2Measurement precision
If three shift ramps are arranged along the stroke range of the shift element, then the measurement precision of shift positions is improved, but the device complexity increases
Solution Approach 1:
Each shift ramp (first, second, and third) is positioned at a specific location along the stroke range to detect particular shift states. The ramps have different axial positions and interact with sensors at different times during the shift stroke, providing localized detection points that collectively deliver precise overall measurement without requiring a complex unified structure
Solution Approach 2:
The shift ramps are arranged in the axial dimension along the stroke range of the shift element. This spatial arrangement in one dimension allows the system to encode multiple shift position information points, achieving precise measurement of shift progression without adding complexity in other dimensions
3Measurement precision
If the sensors are arranged to interact with multiple shift ramps over the stroke range, then the detection accuracy is improved, but the ease of manufacture decreases
Solution Approach 1:
The shift ramps are pre-positioned at specific axial locations along the shift element stroke range during manufacturing. This preliminary arrangement ensures that as the shift element moves through its stroke, the sensors automatically encounter the ramps in the correct sequence at the correct positions, achieving accurate detection without requiring complex post-assembly adjustments
Data Source
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AI summary
The invention relates to a shift position detection device (60) for detecting the shift positions of a mechanical two-speed transmission, in particular a standstill transmission, wherein the transmission has shift positions for a first shift stage (G1), for a second shift stage (G2), and for a neutral position (N) of the transmission, which constitutes an idle position. The shift position detection device (60) has two sensors (S1, S2) which interact with several shift ramps (61, 62, 63) that are longitudinally movable relative to the sensors (S1, S2), wherein in the neutral position (N) of the transmission both sensors (S1, S2) are actuated, and during a stroke movement of a shift element of the transmission provided for switching the shift positions, only one of the two sensors (S1, S2) changes its switching state.