Steering Torque Sensor Magnet Radial Positioning
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Solution Overview
Problem
Magnet-based torque measurement systems in steering systems face precision issues due to increased shaft rigidity, resulting in smaller magnetic field changes and less precise signal output.
Innovation Solution
A sensor device with a magnet arranged inside a magnet holder at a radial distance from the shaft, allowing for a larger radial distance and significant magnetic field change detection, enhancing signal quality or reducing installation space while maintaining signal quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the shaft rigidity is increased, then the structural strength is improved, but the torque measurement precision deteriorates due to smaller magnetic field changes
Solution Approach 1:
The magnet is positioned inside the magnet holder at a radial distance from the shaft, utilizing the radial dimension to maximize the magnetic field change path. This dimensional arrangement allows the magnet to traverse a larger arc length during shaft torsion, generating stronger magnetic field variations that can be detected even when shaft rigidity is high and torsion angles are small.
Solution Approach 2:
The invention changes the positional parameter of the magnet from the conventional outside arrangement to an inside arrangement within the magnet holder. This parameter change increases the radial distance between the magnet and the shaft, thereby amplifying the magnetic field change detection capability while maintaining compatibility with high-rigidity shafts.
2Ease of manufacture
If the magnet is arranged on the outside of the magnet holder, then the design is simplified, but the signal quality deteriorates due to smaller magnetic field changes
Solution Approach 1:
By repositioning the magnet inside the magnet holder rather than on the outside, the invention utilizes the internal radial space to create a longer magnetic field change path. This dimensional reconfiguration increases the arc length traversed by the magnet during shaft rotation, thereby enhancing signal quality without significantly complicating the manufacturing process.
3Measurement precision
If the radial distance between magnet and shaft is increased, then the magnetic field change detection is improved, but the installation space requirement increases
Solution Approach 1:
The magnet is nested inside the magnet holder, utilizing the internal cavity space of the holder structure. This nesting arrangement allows the magnet to be positioned at an optimal radial distance from the shaft for maximum signal detection, while the overall external dimensions of the magnet holder remain compact, thus not increasing the installation space footprint.
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
Achieves a signal improvement of up to 50% or reduces installation space with the same signal quality, providing a more accurate torque measurement.
Implementation Method 1
a magnet arranged non-rotatably on a shaft of the steering system and a magnetic field sensor which is arranged on a second section of the shaft relative to the magnet... a change in the magnetic field emanating from the magnet is detected by the sensor
Data Source
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AI summary
A sensor device for measuring torque in vehicle steering systems comprises a magnet that is arranged in a rotationally fixed manner on a shaft, and a magnetic field sensor. The magnet is mounted on a magnet holder that is to be connected to the shaft. The magnet holder has a receiving zone located at a radial distance from the shaft, and the magnet is arranged on the internal side of the receiving zone which faces the shaft.