3D Hall Shift Fork Position Detection Under Play and Wear
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Solution Overview
Problem
Conventional linear sensors are inadequate for accurately measuring the position of pivoting shift forks in transmissions due to mechanical play and wear, leading to measurement errors and signal noise, especially when the signal generator rotates relative to the receiver.
Innovation Solution
A 3D Hall sensor apparatus is used, with a magnet as the signal generator attached to the actuating element, allowing for precise spatial measurement of linear, rotational, and pivoting movements, eliminating the need for direct targeting of the magnetic field and reducing installation costs by allowing flexible cabling and reduced sensor count.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a linear sensor is used to measure the position of a shift fork, then the measurement can be performed with a simple sensor structure, but measurement errors occur due to mechanical play and wear between the actuating element and shift fork
Solution Approach 1:
The patent replaces the mechanical contact-based linear sensor system with a magnetic field-based sensing system. A magnet is attached to the actuating element (piston rod or shifting piston), and a Hall sensor detects the magnetic field position. This substitution eliminates mechanical play and wear issues because the magnetic field detection does not require physical contact between the sensor and the moving part, thereby maintaining measurement precision while avoiding the drawbacks of mechanical systems.
Solution Approach 2:
The patent introduces a magnet as an intermediary between the actuating element and the Hall sensor. The magnet creates a magnetic field that serves as the medium for position detection, allowing the Hall sensor to detect the position of the actuating element indirectly through the magnetic field rather than through direct mechanical contact. This intermediary approach resolves the contradiction by enabling accurate measurement without mechanical contact.
2Measurement precision
If the signal generator is provided on the actuating element, then the position can be sensed directly, but mechanical play and wear between the actuating element and shift fork cause signal noise and measurement errors
Solution Approach 1:
The patent replaces the mechanical coupling system with a magnetic field-based system. The magnet attached to the actuating element generates a magnetic field that is detected by the Hall sensor, eliminating the need for mechanical contact between the actuating element and the sensor. This substitution ensures that mechanical play and wear do not affect signal stability, as the magnetic field detection is independent of mechanical tolerances and wear.
Solution Approach 2:
The patent changes the detection parameter from mechanical position (requiring direct contact) to magnetic field position (detectable through field interaction). By using the Hall sensor to detect the magnetic field generated by the magnet on the actuating element, the system can determine the position parameter without relying on mechanical contact, thereby maintaining signal stability despite mechanical play and wear.
3Device complexity
If a linear sensor is used for pivoting shift fork movement, then the sensor can be installed with simple structure, but the sensor cannot accurately track the nonlinear pivoting movement of the shift fork
Solution Approach 1:
The patent replaces the mechanical linear sensor system with a magnetic field-based Hall sensor system. The magnet attached to the actuating element moves with the pivoting motion, and the Hall sensor detects the changing magnetic field position. This substitution allows the system to accurately track nonlinear pivoting movements without requiring complex mechanical sensor installations, as the magnetic field naturally follows the motion path of the actuating element.
Solution Approach 2:
The patent transitions from one-dimensional linear measurement to three-dimensional magnetic field detection. The Hall sensor can detect the magnet's position in multiple dimensions (x, y, z coordinates) by sensing the magnetic field vector components. This dimensional expansion enables accurate measurement of pivoting movements that have both linear and angular components, which cannot be captured by simple linear sensors.
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 3D Hall sensor system provides improved accuracy and reliability in measuring shift fork positions, compensating for mechanical changes and wear, and reducing signal noise, ensuring precise detection of shift positions even under disruptive influences, while minimizing installation space and costs.
Implementation Method 1
The invention relates to a device having a Hall sensor apparatus for sensing the position of a shift fork in a transmission
Data Source
AI summary
In a device for sensing the position of a shift fork in a transmission, the shift fork is connected to a piston rod of a shifting piston which is guided axially in a shifting cylinder. The shift fork engages an axially slidable sliding sleeve, which slides on a transmission shaft, to engage or disengage a transmission stage. A magnet functioning as a signal generator is arranged on an actuating element, such as the switching piston, piston rod or shift fork. A 3D Hall sensor positionally fixed relative to the magnet functions as a signal receiver, sensing a magnetic field generated by the magnet. An electronic control unit connected to the 3D hall sensor determines the position of the shift fork from the relative positions of the magnet and 3D Hall sensor and transmits the position as a signal, taking into account linear, rotational, and/or pivoting movements of the actuating element.