Torque Sensor Magnetic Shielding via Conductive Housing
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Solution Overview
Problem
Existing torque sensors in motor vehicles are susceptible to external magnetic interference, particularly in electric vehicles with high-current cables, leading to inaccurate torque measurements.
Innovation Solution
An electromechanical steering system with a torque sensor unit featuring a ring magnet, magnetic yokes, and magnetic flux conductors, surrounded by a magnetically conductive housing and inner casing tube for comprehensive magnetic shielding, protecting the sensor unit from external magnetic fields.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If magnetic shielding is added to the torque sensor unit, then measurement accuracy is improved, but device complexity increases
Solution Approach 1:
The magnetic shielding function is merged with the existing housing structure. The housing is made of magnetically conductive material and forms an integrated shield around the sensor unit, eliminating the need for separate shielding components while providing both structural support and magnetic protection.
Solution Approach 2:
The housing serves multiple functions: it provides mechanical protection for the sensor components, structural support for mounting, and magnetic shielding through its magnetically conductive material. This multi-functionality reduces overall device complexity while maintaining measurement accuracy.
2Object-affected harmful factors
If a complete housing enclosure is used for magnetic shielding, then shielding effectiveness is improved, but ease of manufacture deteriorates
Solution Approach 1:
The housing is divided into multiple segments or components that can be manufactured separately and then assembled. This segmentation allows for easier manufacturing of individual parts while still achieving complete magnetic shielding when assembled together, as each segment contributes to the overall shielded enclosure.
3Object-affected harmful factors
If magnetically conductive material is used for the housing, then magnetic shielding is improved, but weight increases
Solution Approach 1:
The magnetically conductive material is applied selectively to specific areas of the housing where magnetic shielding is most needed, rather than uniformly throughout. This local application provides effective shielding against external magnetic fields while minimizing the overall weight increase of the steering system.
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 magnetic shielding significantly reduces the influence of external magnetic interference, enhancing the accuracy of torque measurements and ensuring reliable operation in electric vehicles.
Implementation Method 1
the second housing and the housing cover are made of a magnetically conductive material for magnetic shielding of the torque sensor unit
Implementation Method 2
at least one magnetic yoke that can be connected to the second partial shaft and is arranged in a magnetic field emanating from the ring magnet
Data Source
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AI summary
The invention relates to a torque sensor unit (1) comprising: - a ring magnet (4) which can be connected to a first partial shaft (2) for conjoint rotation therewith; - at least one magnet yoke (5) which can be connected to a second partial shaft and is arranged in a magnetic field caused by the ring magnet (4); and - at least two magnetic flux conductors (6) which can be connected to the second partial shaft and conduct the magnetic fluxes generated by the at least one magnet yoke (5); - a sensor unit (7) having a first housing (8), which sensor unit detects a change in rotational angle between the partial shafts (2) by measuring the magnetic flux densities generated between the magnetic flux conductors (6); - a second housing (12) which surrounds the ring magnets (4), the at least one magnet yoke (5), the at least two magnetic flux conductors (6) and the sensor unit (7), and has a housing opening (123) which is at least partly closed by a housing cover (13), wherein the second housing (12) and the housing cover (13) are made of a magnetically conductive material for magnetic shielding of the torque sensor unit (1).