Torque Sensor Magnetic Shielding and Collector Alignment
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Solution Overview
Problem
Existing torque sensors in power steering systems are affected by external magnetic fields, leading to inaccurate measurements and manufacturing complexities due to collector deformation and gap maintenance issues during assembly.
Innovation Solution
A sensing device design featuring a stator with overlapping teeth and collectors, where a sensor is placed between the collectors to minimize magnetic interference, and a housing with specific protrusions to maintain collector alignment and prevent deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a torque sensor uses a magnetic type structure with a collector disposed outside the stator tooth, then the sensor can measure torque, but the external magnetic field affects the magnetic flux value of the Hall IC, causing inaccurate measurements
Solution Approach 1:
A magnetic shield is introduced as an intermediary component between the external magnetic field source and the Hall IC. This shield redirects the external magnetic field lines away from the sensor core, preventing them from interfering with the magnetic flux measurement. The shield acts as a mediator that protects the sensitive Hall IC from harmful external magnetic fields while allowing the sensor to continue measuring torque accurately.
Solution Approach 2:
The patent utilizes the external magnetic field lines and redirects them through the magnetic shield to flow along a predetermined path that enhances the measurement capability. By strategically designing the shield geometry, the external magnetic field is converted from a harmful interference into a beneficial element that can be directed through the sensor core to improve flux detection, thereby transforming the harmful external field into a useful measurement resource.
2Stability of the object's composition
If two collectors are fixed to a housing during a fusion process, then the collectors are secured in position, but the gap between the outer connector and inner collector changes or the collector height changes, causing performance problems
Solution Approach 1:
Positioning protrusions are provided on the collectors that engage with corresponding positioning recesses in the housing before the fusion process. This preliminary positioning action establishes the correct gap and height dimensions prior to fusion, ensuring that the collectors are pre-aligned to the precise required positions. The fusion process then simply secures the collectors in these pre-established positions, preventing dimensional changes during assembly.
Solution Approach 2:
The patent modifies the physical parameters of the collector structure by adding protrusions with specific geometries that interface with the housing. These protrusions change the positional parameters (gap and height) from variable during fusion to fixed and controlled. By altering the structural parameters of the collector, the manufacturing precision is improved as the protrusions act as mechanical constraints that maintain dimensional accuracy throughout the fusion process.
3Strength
If protrusions on a stator body are fused to couple a stator tooth to the stator body, then the components are joined, but there are multiple fusion points making management difficult and the manufacturing process complicated
Solution Approach 1:
Multiple separate protrusions on the stator body are merged into a single integrated protrusion structure that couples the stator tooth to the stator body. Instead of having multiple discrete fusion points distributed around the stator, the design consolidates the coupling function into one unified fusion zone. This merging reduces the number of fusion operations required, simplifies quality control and inspection, and reduces manufacturing complexity while maintaining the necessary coupling strength through the integrated structure.
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 design effectively reduces external magnetic field interference, maintains collector alignment, and simplifies the manufacturing process by preventing collector separation and deformation, ensuring accurate torque measurements and improved sensor performance.
Implementation Method 1
a change occurs in an output value of the torque sensor, and thus there is a problem in that the degree of torsion of the torsion bar cannot be accurately measured
Data Source
AI summary
Provided in one embodiment is a sensing device comprising a stator including a stator tooth, and a rotor including a magnet, wherein the stator tooth includes a first stator tooth and a second stator tooth arranged in the first stator tooth, the first stator tooth includes a plurality of first teeth, second stator tooth includes a plurality of second teeth, and the first teeth overlap with the second teeth in the radial direction from the center of the stator, the sensing device further comprising a first sensor and a collector arranged between the first stator tooth and the second stator tooth in the radial direction, wherein the collector includes a first collector and a second collector arranged in the first collector, the first sensor is arranged between the ring-shaped first collector and the ring-shaped second collector in the radial direction, the first collector and the second collector respectively include a body arranged to face the first sensor, and an extending part that extends from the body, the extending part includes a protrusion part protruding from one side edge of the extending part in the axial direction, and the protrusion part includes areas that differ in width in the circumferential direction.