Steering Angle Sensor Magnetic Rotor Resolution
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Solution Overview
Problem
Conventional steering angle sensors face limitations in resolution and durability due to manufacturing constraints and wear from soiling, with existing solutions either requiring excessive space or increased actuation forces, and failing to achieve high precision.
Innovation Solution
A compact steering angle sensor design featuring a main rotor and an additional rotor with a gear member, utilizing magnetic field sensors with non-integer transmission ratios and magnet sections of different polarity to achieve high resolution without optical means, allowing for accurate steering wheel angle detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If optical means with code discs are used for scanning rotational angle position, then the sensor can detect steering angle, but the resolution is limited to approximately 1.5° due to manufacturing limits and the means are subject to wear from soiling
Solution Approach 1:
The patent replaces optical code discs with magnetic field sensors and magnet sections. Instead of using optical means that are subject to wear, the invention uses magnetic fields interact between magnet sections on the rotor and corresponding sensors, eliminating the wear problem while achieving higher resolution through the magnetic interaction pattern.
Solution Approach 2:
The patent changes the detection parameter from optical code patterns to magnetic field interactions. By using magnet sections with specific polarities arranged on the rotor and corresponding magnetic sensors, the system achieves higher resolution (0.1°) compared to optical methods while improving reliability since magnetic fields are not affected by soiling or wear.
2Measurement precision
If two additional rotors are used to improve resolution to 0.1°, then measurement precision is improved, but the device requires relatively large space and increases actuation forces
Solution Approach 1:
The patent merges the functions of multiple rotors into a single rotor structure. Instead of requiring two additional rotors as in prior art, the invention uses one rotor equipped with multiple magnet sections that can be scanned by corresponding sensors, achieving the same 0.1° resolution while reducing spatial requirements and actuation forces.
Solution Approach 2:
The patent transitions from a mechanical multiplication approach (multiple rotors) to a magnetic field interaction approach. By arranging magnet sections with different polarities on a single rotor and using corresponding magnetic sensors, the system achieves high resolution through the dimensional arrangement of magnetic poles rather than through mechanical multiplication of rotors.
3Device complexity
If conventional code discs with teeth of different width are used, then the sensor structure is simple, but the resolution can only achieve approximately 1.5° due to manufacturing limits
Solution Approach 1:
The patent replaces mechanical code discs with teeth with a magnetic field-based detection system. Instead of relying on mechanical features that are limited by manufacturing precision, the invention uses magnetic field interactions between magnet sections and sensors, achieving 0.1° resolution while maintaining structural simplicity through the magnetic detection approach.
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 solution provides a compact, high-resolution steering angle sensor resistant to wear, capable of precise angle detection with minimal space requirements, suitable for various installation locations and vehicle functions.
Implementation Method 1
magnetic field sensors with non-integer transmission ratios and magnet sections of different polarity
Data Source
AI summary
A steering angle sensor comprises a main rotor which can be rotated in a rotationally synchronous manner and which can be coupled to a steering column or to a steering wheel. The main rotor can be rotated about the rotational axis of the steering column. The steering angle sensor also comprises at least one additional rotor which can be driven by the main rotor, a first scanning unit which is used to scan the position of the rotational angle of the main rotor, and a second scanning unit which is used to scan the rotational angle of the additional rotor. The additional rotor can be rotated about the rotational axis of the steering column and can drive the additional rotor of at least one transmission element driven by the main rotor. A method for determining the absolute steering angle of a steering wheel is also disclosed.