Steering System Rotation Sensor Magnetic Interference Compensation
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Solution Overview
Problem
Conventional rotary sensors in motor vehicle steering systems face challenges in ensuring high reliability and accuracy under specific operating conditions, particularly due to external magnetic interference fields.
Innovation Solution
The proposed steering system incorporates an anti-twist device with ferromagnetic material on the steering shafts and flux guides with specific area ratios between collecting and compensator sections, which helps in deflecting and compensating external magnetic interference fluxes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional rotary sensors are used in steering systems, then the basic rotation detection function is provided, but the measurement accuracy deteriorates due to external magnetic interference fields
Solution Approach 1:
The patent introduces flux conductors as intermediary components that guide and filter magnetic flux from the sensor element to the stator elements. These flux conductors act as mediators that selectively transmit the measuring flux while blocking external magnetic interference fields, thereby protecting the measurement system from harmful external magnetic factors without requiring direct shielding of the sensor element itself
Solution Approach 2:
The patent converts the harmful external magnetic interference flux into a useful compensation signal. By allowing the interference flux to couple into the compensator section of the flux conductor, the system measures and compensates for the interference effect, transforming the harmful external field into a correctable parameter that improves measurement accuracy through active compensation
2Reliability
If flux conductors with compensator sections are added to counteract interference, then measurement robustness improves, but device complexity increases
Solution Approach 1:
The patent merges the interference compensation function into the existing flux conductor structure by adding compensator sections to the flux conductors that are already present in the sensor assembly. Instead of introducing separate compensation devices, the compensator sections are integrated into the flux conductors, combining the flux guidance and interference compensation functions into a single unified structure
Solution Approach 2:
The flux conductors are designed to perform multiple functions simultaneously: guiding the magnetic flux from the sensor element to the stator elements, filtering out external magnetic interference, and providing compensation for remaining interference effects. This multi-functionality reduces the need for separate dedicated components for each function, thereby limiting the increase in overall device complexity
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
This configuration significantly improves the accuracy and robustness of steering input detection, enhancing the operational reliability of the motor vehicle steering system by effectively mitigating the impact of external magnetic interference.
Implementation Method 1
The magnetic element is designed such that it couples a magnetic flux into the stator elements that depends on the relative angular orientation
Implementation Method 2
The sensor element, for example, comprises a Hall or magnetoresistive (GMR) sensor element, in which the magnetic flux introduced via the flux conductors is converted into an electrical signal
Implementation Method 3
an anti-twist device arranged on the upper steering shaft is engaged with an anti-twist device arranged on the lower steering shaft to limit twisting of the torsion bar in itself, wherein the anti-twist device comprises a ferromagnetic material
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
The present invention relates to a steering system (1) for a motor vehicle with a rotation sensor (4), comprising a magnetic element (41) attached to a steering shaft (10) rotatable with it about an axis (L) and two stator elements (42a,b) arranged coaxially relative to the steering shaft (10) and spaced axially apart from each other, which are operatively connected to at least one sensor element (6) via two flux conductors (5a,b), wherein each flux conductor (5a,b) has a collecting section (51a,b), a connecting section (53a,b) and a compensator section (52a,b), wherein the collecting section (51a,b) is connected to a stator element (42a,b) and is connected to the compensator section (52a,b) via a connecting section (53a,b), and wherein the sensor element (6) is arranged between the two flux conductors (5a,b).To enable improved and more robust detection of steering inputs, the invention proposes that the compensator section (52a,b) has a compensator area that is less than or equal to a collecting area of the collecting section (51a,b).