Form-Locking Shift Element Torque Detection via Magnetic Sensor
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Solution Overview
Problem
Form-locking shift elements in transmissions face challenges in accurately determining their operating conditions, leading to inefficient gear changes, drag torques, and prolonged shift times due to issues like tooth-on-tooth positions and flank clamping, which affect ride comfort and shift quality.
Innovation Solution
A method for determining the operating condition of form-locking shift elements using parameterizable threshold values and sensor monitoring to detect sufficient overlap between shift-element halves, allowing for precise torque transmission and efficient engagement, thereby reducing unnecessary actuation measures and improving shift quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If form-locking shift elements are used to eliminate drag torques, then transmission efficiency is improved, but accurate determination of operating condition becomes difficult leading to prolonged shift times
Solution Approach 1:
The patent replaces mechanical position detection methods with a magnetic field-based sensor system. A magnetic sensor detects the position of a ferromagnetic component on the shift element by monitoring changes in magnetic field strength, enabling non-contact, precise determination of the shift element's operating condition without mechanical wear or complexity.
Solution Approach 2:
The patent introduces a ferromagnetic component as an intermediary between the shift element and the magnetic sensor. This intermediary carries magnetic identifiers that encode position information, allowing the sensor to indirectly detect the shift element's state through magnetic field variations without direct mechanical contact.
2Device complexity
If simple software-based evaluation of actuating current is used, then control complexity is reduced, but measurement precision of operating condition deteriorates
Solution Approach 1:
The patent replaces electrical current evaluation with a magnetic field-based detection system. The magnetic sensor directly measures the position of the shift element through magnetic field strength variations, providing precise operating condition detection without requiring complex software analysis of actuating currents.
3Reliability
If complete engagement is required before torque transmission, then reliability is improved, but shift times are prolonged due to unnecessary actuation measures
Solution Approach 1:
The patent enables preliminary torque transmission by detecting when the shift element has reached a sufficient engagement position using magnetic field detection. The control unit can authorize torque transmission before complete engagement is achieved, as the magnetic sensor provides real-time position feedback that confirms adequate overlap between shift element halves, eliminating unnecessary waiting time.
Solution Approach 2:
The patent implements a feedback mechanism where the magnetic sensor continuously monitors the position of the shift element and provides real-time information to the control unit. This feedback loop allows the control unit to make informed decisions about when to authorize torque transmission based on actual engagement status, optimizing the balance between reliability and shift speed.
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 method enables high-quality actuation of form-locking shift elements within short shift times, reducing drag torques and improving overall transmission efficiency by accurately determining the engaged or disengaged states, thus enhancing gear change operations and ride comfort.
Implementation Method 1
A current position of the shift-element half is monitored with a sensor
Data Source
AI summary
A form-locking shift element may include a first shift-element half and a second shift-element half which are engageable with each other by moving at least the first shift-element half. A method for determining an operating condition of the form-locking shift element may include monitoring a position of the first shift-element half with a sensor, and, when a value of a signal generated by the sensor is greater than an applicable value and when the first shift-element half is actuated and displaced towards an engaged operating condition, determining that the shift element is sufficiently engaged to transmit a torque at the form-locking shift element. The applicable value corresponds to a defined overlap between the first and second shift-element halves that is less than an overlap when the first shift-element half is in the engaged operating condition.