Magnetic Sensor Stacking for Uniform Output
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Solution Overview
Problem
Conventional rotation detection devices face challenges in reducing sensor unit size while ensuring uniform outputs from multiple magnetic sensors, with existing configurations either increasing size or leading to non-uniform outputs due to varying distances from the detection target.
Innovation Solution
The rotation detection device features magnetic sensors aligned in the plate thickness direction with their detection portions facing the axial end face of the detection target member, allowing for uniform output and reduced size, utilizing a housing portion that minimizes size and maintains accurate detection by positioning sensors to detect magnetic fields perpendicularly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of stationary object
If multiple magnetic sensors are stacked in the plate thickness direction to reduce sensor unit size, then the sensor unit size is reduced, but the outputs of the magnetic sensors become non-uniform due to different distances from the detection target member
Solution Approach 1:
The patent places multiple magnetic sensors in a nested configuration where they share a common detection axis. The detection portions are arranged concentrically or in overlapping positions along the thickness direction, allowing compact stacking while maintaining uniform detection distance to the rotating member, thus achieving both size reduction and output uniformity
Solution Approach 2:
The patent designs the sensor arrangement so that all magnetic sensors are positioned at equipotential detection positions relative to the detection target member. By ensuring equal magnetic field exposure through careful positioning and orientation, all sensors produce uniform outputs despite being stacked in the thickness direction
2Manufacturing precision
If multiple magnetic sensors are aligned in the width direction to achieve uniform outputs, then output uniformity is improved, but the sensor unit size increases
Solution Approach 1:
The patent transitions from lateral arrangement (width direction) to vertical stacking (thickness direction) of magnetic sensors. By utilizing the thickness dimension for sensor placement while maintaining uniform detection geometry through proper orientation, the design achieves compact size without sacrificing output uniformity
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 achieves a compact sensor unit with uniform outputs from magnetic sensors, maintaining detection accuracy and versatility by aligning sensors in the plate thickness direction and positioning them to detect magnetic fields perpendicularly, thus enhancing detection precision and reducing manufacturing complexity.
Implementation Method 1
a magnetic detection element to detect a magnetic field from the detection target member
Data Source
AI summary
A rotation detection device includes a sensor unit including plural magnetic sensors and a housing portion covering the magnetic sensors together. The magnetic sensors each include a plate-shaped detection portion including a magnetic detection element to detect a magnetic field from a detection target member and connection terminals extending out of the detection portion. The magnetic sensors are arranged such that the detection portions are aligned in a plate thickness direction thereof. The magnetic detection element is configured to detect a magnetic field in a direction perpendicular to the plate thickness direction. The sensor unit is positioned such that fore-end portions of the detection portions of the magnetic sensors face toward an axial end face of the detection target member, the fore-end portions being end portions located opposite to the side where the connection terminals extend out.