Flux Ring Torque Sensor Axial Magnetic Reading
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Solution Overview
Problem
Existing sensor systems for detecting differential angles caused by torque on a shaft are sensitive to axial tolerances and external interference fields, leading to reduced magnetic flux and signal quality, particularly in motor vehicles with electrically assisted steering systems.
Innovation Solution
The design features flux rings with radially oriented teeth that interlock and collect magnetic information from a magnetic pole wheel, allowing for optimized tolerance behavior and reduced impact of axial movements, along with the use of magnetic yoke plates to enhance magnetic flux and resistance to external interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If axial tolerances are reduced to improve signal quality, then measurement precision improves, but manufacturing precision requirements increase and device complexity increases
Solution Approach 1:
The invention transitions from radial reading (sensitive to axial tolerances) to axial reading at the end surface (insensitive to axial tolerances). The flux rings read magnetic information axially from the end surface of the magnetic pole wheel, changing the reading dimension from radial to axial, thereby eliminating sensitivity to axial position variations.
Solution Approach 2:
The flux rings with radially oriented teeth act as intermediaries that collect and transmit magnetic information from the magnetic pole wheel to the sensors. The teeth are positioned to reliably overlap the magnets radially while reading axially, serving as a mediator that decouples the reading process from axial position variations.
2Measurement precision
If axial tolerances are reduced to improve signal quality, then measurement precision improves, but device complexity increases
Solution Approach 1:
By reading magnetic information axially at the end surface instead of radially, the system becomes insensitive to axial tolerances. The flux rings with radially oriented teeth collect magnetic flux from the end surface of the magnetic pole wheel, and sensors positioned axially read this information, eliminating the need for tight axial tolerance control.
Solution Approach 2:
The flux rings serve as intermediary components that collect magnetic information from the magnetic pole wheel and present it to the sensors in a way that is insensitive to axial position. This intermediary structure simplifies the overall device by eliminating the need for complex tolerance control mechanisms.
3Reliability
If magnetic yoke plates are added to increase magnetic flux and resistance to external interference, then reliability improves, but device complexity increases
Solution Approach 1:
The magnetic yoke plates are integrated with the existing flux rings and magnetic pole wheel structure. The yoke plates are positioned to work in conjunction with the flux rings, combining multiple functions (flux concentration and interference shielding) into a unified structure rather than adding separate components.
Solution Approach 2:
The magnetic yoke plates serve multiple functions: they concentrate magnetic flux to improve signal strength and simultaneously provide shielding against external magnetic interference. This multi-functionality improves reliability without requiring separate components for each function.
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 design improves signal detection quality by minimizing the effect of axial movements and external interference, resulting in a more reliable and robust torque sensor system with enhanced magnetic flux and simplified assembly.
Implementation Method 1
Hall effect-based sensors can detect magnetic field changes that are caused by the angle change or torque
Implementation Method 2
The magnetic circuit of the device is composed of a magnet ring, two flux rings, and one or more Hall elements. Rotating the magnet in the flux rings causes a change in the magnetic field intensity between the flux rings
Data Source
AI summary
The invention relates to a sensor arrangement for detecting a difference angle, comprising at least one magnet field-sensitive sensor element (12), with which the magnetic field information of a magnetic circuit, consisting of a magnetic pole wheel (10) and of ferromagnetic flux rings (14, 16) with teeth (18, 20), can he evaluated. The invention is characterized in that the teeth (18, 20) extend in a radial direction for radially tapping the magnetic field information of the magnetic pole wheel (10).