Torque Sensor Yoke Asymmetry for Flux Uniformity
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Solution Overview
Problem
Conventional torque detecting devices face challenges in accurately detecting torsional torque due to positional deviations of the magnetic sensor, as the magnetic flux density varies significantly between the inside and outside of a bent magnetic body, requiring precise assembly to maintain detection accuracy.
Innovation Solution
The torque detecting device incorporates a magnet and pair of magnetic yokes with radially extending wall portions, where the distance between the inner and outer distal ends of these wall portions is adjusted to ensure consistent magnetic flux density detection, allowing for positional deviations of the magnetic sensor without affecting the measured torque.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the magnetic sensor is disposed at the bent portion to detect magnetic flux density, then the detection position is fixed, but the magnetic flux density varies significantly between inside and outside of the magnetic body causing detection inaccuracy
Solution Approach 1:
The magnetic yoke is designed with an asymmetric cross-sectional shape featuring a radially outward protruding portion. This asymmetric geometry creates a specific magnetic flux distribution pattern where the flux density becomes relatively uniform at a particular radial position, allowing the magnetic sensor to detect consistent values even with positional deviations.
Solution Approach 2:
The invention changes the geometric parameters of the magnetic yoke by adding a radially outward protruding portion with specific dimensions. This parameter modification alters the magnetic flux distribution, creating a region where flux density is relatively uniform, thereby improving detection accuracy and reducing sensitivity to positioning errors.
2Ease of manufacture
If the magnetic sensor position is allowed to deviate, then assembly is easier, but the magnetic flux density detected becomes inconsistent
Solution Approach 1:
By modifying the geometric parameters of the magnetic yoke (adding radial protrusion), the invention creates a broader detection zone with uniform flux density, allowing positional deviations without compromising measurement consistency.
Solution Approach 2:
The asymmetric magnetic yoke design creates an equipotential-like region in terms of magnetic flux density distribution. At the designed radial position, the flux density becomes relatively uniform, meaning that small positional deviations do not result in significant changes in detected values, effectively creating a tolerance zone for assembly variations.
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 ensures that the magnetic flux density is averaged, maintaining detection accuracy even with radial positional deviations of the magnetic sensor, thereby simplifying its arrangement and improving the overall detection of torsional torque.
Implementation Method 1
a magnetic sensor that detects a magnetic flux density between the pair of magnetic yokes
Implementation Method 2
Magnetic force lines have the property of passing through places with high magnetic permeability along a shape of a magnetic body
Implementation Method 3
the magnetic force lines have the property of continuing in a straight line in the magnetic body
Data Source
AI summary
Claw portions opposing a magnet are disposed on inner edges of a first yoke and a second yoke. Wall portions are disposed on outer edges of the first yoke and the second yoke so as to extend in an axial direction. A distal end of the wall portion and another distal end of the other wall portion are spaced apart from each other in the axial direction and disposed to oppose each other. A magnetic sensor is disposed between the distal ends in the axial direction. End faces oblique to the axial direction are disposed on the distal ends and a distance between the distal ends on a radially inner side is made shorter than a distance between the distal ends on a radially outer side.