Wheel Speed Sensor Layout for Stronger Magnetic Flux Detection
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Solution Overview
Problem
Existing wheel speed sensors face challenges in accurately detecting wheel speed due to minimal changes in magnetic flux density away from the outer edge of the rotor, limiting their detection accuracy.
Innovation Solution
A wheel speed sensor is positioned closer to the center line of a ring-shaped rotor with alternating magnetic poles, using multiple magnetic field detectors held by an attachment member that optimizes their placement between the rotor's outer and inner peripheral lines, ensuring larger changes in magnetic flux density are detected.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the detection elements are positioned at the outer edge portion of the rotor, then the structure is simplified, but the magnetic flux density changes minimally resulting in poor detection accuracy
Solution Approach 1:
The patent applies local quality by positioning detection elements at specific radial locations where magnetic flux density changes are maximized. The holding portion is designed to hold detection elements at an intermediate radial position rather than uniformly at the outer edge, creating localized optimal detection zones where the magnetic field variation is sufficient for accurate speed detection.
Solution Approach 2:
The patent changes the radial position parameter of the detection elements from the outer edge portion to an intermediate position between the outer and inner peripheral lines. This parameter change optimizes the magnetic flux density variation detected by the elements, thereby improving wheel speed detection accuracy without significantly complicating the overall structure.
2Measurement precision
If the detection elements are positioned away from the outer edge of the rotor, then larger magnetic flux density changes are detected, but the structural simplicity is reduced
Solution Approach 1:
The holding portion serves multiple functions: it holds the detection elements in place, positions them at the optimal radial location for detecting magnetic flux density changes, and integrates with the attachment member to secure the entire sensor assembly. This multi-functionality improves detection accuracy while maintaining manufacturing simplicity through a single integrated component.
3Reliability
If multiple magnetic field detectors are used at optimized positions, then detection accuracy is improved, but the device complexity increases
Solution Approach 1:
The patent merges multiple detection elements and the holding structure into a single integrated holding portion. This combination allows multiple magnetic field detectors to be positioned at optimized locations while maintaining a compact, unified structure that does not significantly increase overall device complexity. The integrated design improves reliability through multiple detection points while keeping the assembly manageable.
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 enhances the accuracy of wheel speed detection by capturing larger fluctuations in magnetic flux density, improving the sensor's performance and reliability.
Implementation Method 1
a plurality of detection elements that detect fluctuations in magnetic fields caused by the rotation of a rotor that rotates with a wheel and convert this fluctuation into an electric signal
Data Source
AI summary
A wheel speed sensor includes a plurality of magnetic field detectors configured to output detection signals that correspond to magnetic field fluctuation caused by a rotation of a rotor; and an attachment member that includes an attachment portion that is to be attached to a vehicle and a holding portion that is configured to hold the plurality of magnetic field detectors, and that, in a state in which the attachment portion is attached to the vehicle, when viewed along a center axial direction of the rotor, holds the plurality of magnetic field detectors at a position that is closer to a center line, which passes centrally between an outer peripheral line that depicts the outer periphery of the rotor and an inner peripheral line that depicts the inner periphery of the rotor, than to the outer peripheral line and the inner peripheral line.