Segmented Magnet Design for Rotation Angle Sensor
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Solution Overview
Problem
Existing rotation angle sensors with cylindrical magnets face challenges in increasing the magnetic field strength while minimizing angle errors due to misalignment between the magnet and sensor, without causing excessive proximity issues that could lead to damage.
Innovation Solution
A rotation angle sensor design featuring a magnet with a plate-shaped portion and a ring-shaped portion, where the plate-shaped portion does not have a hollow axis and the ring-shaped portion does, allowing for increased magnetic field strength and reduced angle errors without excessive distance reduction between the magnet and sensor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the magnet size is increased to enhance magnetic field strength, then the magnetic field strength improves, but the distance between the magnet and sensor becomes excessively small, risking contact and damage
Solution Approach 1:
The magnet is divided into two distinct portions: a plate-shaped portion that generates the magnetic field and a ring-shaped portion that provides structural support and maintains spacing. This segmentation allows the magnetic field-generating portion to be optimized for strength while the ring portion ensures adequate distance from the sensor, preventing contact damage.
2Strength
If the magnet and sensor are positioned closer to increase magnetic field strength, then the magnetic field strength improves, but angle errors due to misalignment increase
Solution Approach 1:
By separating the magnet into plate-shaped and ring-shaped portions, the design allows the plate-shaped portion to be positioned optimally for strong magnetic field generation while the ring-shaped portion maintains a stable, spaced relationship with the sensor. This reduces the impact of misalignment on angle detection precision.
3Ease of manufacture
If a cylindrical magnet configuration is used to simplify structure, then manufacturing ease improves, but magnetic field strength and angle error performance deteriorate
Solution Approach 1:
The magnet is segmented into a plate-shaped portion for optimal magnetic field generation and a ring-shaped portion for structural support and spacing. This segmented configuration outperforms simple cylindrical designs in magnetic field strength and angle error performance while remaining manufacturable through standard processes.
Solution Approach 2:
Different portions of the magnet are given different functions: the plate-shaped portion is optimized for magnetic field generation with appropriate thickness and material properties, while the ring-shaped portion is optimized for maintaining spacing and structural integrity. This local optimization of properties in different regions achieves superior overall performance.
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 enhances the magnetic field strength and reduces angle errors resulting from misalignment, maintaining a safe distance to prevent sensor-magnet contact, outperforming cylindrical and ring-shaped magnet configurations.
Implementation Method 1
a magnetic sensor that faces the end face of the magnet and detects a magnetic field produced by the magnet
Data Source
AI summary
A rotation angle sensor includes a magnet that rotates about a rotation axis. The magnet has an end face perpendicular to the rotation axis and has a magnetization in a direction perpendicular to the rotation axis. The rotation angle sensor further includes a magnetic sensor that faces the end face of the magnet and detects a magnetic field produced by the magnet. The magnet includes a plate-shaped portion including the end face, and a ring-shaped portion that is located on a side of the plate-shaped portion farther from the end face and coupled to the plate-shaped portion. The plate-shaped portion does not include any hollow through which the rotation axis passes, whereas the ring-shaped portion includes a hollow through which the rotation axis passes.