Magnet Arrangement Flat Field Plateau Assembly Tolerance
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Solution Overview
Problem
Conventional magnet arrangements for angular magnetic sensors are sensitive to assembly tolerances, leading to errors in measured angles, and often result in small magnetic fields that reduce sensed signals.
Innovation Solution
A magnet arrangement comprising a pill-shaped first magnet and a ring-shaped second magnet, both magnetized in the same direction, are designed to create a flat magnetic field plateau with zero slope and curvature at the sensor position, reducing sensitivity to assembly tolerances while maintaining a strong magnetic field.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional magnet arrangements are used, then the device is simple to manufacture, but the sensor becomes sensitive to assembly tolerances causing measurement errors
Solution Approach 1:
The magnet arrangement is divided into multiple magnet portions (first magnet portion, second magnet portion, third magnet portion) with different geometries and magnetization directions. Each portion contributes differently to the magnetic field, creating a composite field that compensates for position deviations and reduces sensitivity to assembly tolerances.
Solution Approach 2:
Different regions of the magnet arrangement have different magnetic properties. The first magnet portion has diametrical magnetization, the second has axial magnetization, and the third has diametrical magnetization perpendicular to the first. This local variation in magnetic quality creates a balanced field that is less sensitive to assembly variations.
2Measurement precision
If optimized magnet arrangements are used to reduce sensitivity to assembly tolerances, then measurement precision improves, but the magnetic field strength decreases
Solution Approach 1:
Multiple magnet portions with different magnetization directions are combined in a single arrangement. The first magnet portion generates radial field components, the second generates axial field components, and the third generates tangential field components. Their combined effect produces a strong, balanced magnetic field that is both intense and insensitive to assembly tolerances.
Solution Approach 2:
The magnet arrangement uses a composite configuration of different magnet types and orientations rather than a single uniform magnet. This composite structure creates a magnetic field with multiple components that reinforce each other, maintaining high field strength while reducing sensitivity to position 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
The design effectively mitigates the influence of assembly tolerances and maintains a large magnetic field, providing robust and accurate angle measurements.
Implementation Method 1
A magnet arrangement comprises a first magnet portion, a second magnet portion and a third magnet portion... The magnet arrangement is designed such that an axial component of a magnetic field generated by the magnet arrangement... has a zero first derivative and a zero second derivative with respect to the axial position at an axial position of the sensor element
Data Source
AI summary
Magnet arrangements, sensor devices and corresponding methods are provided comprising a first magnet portion and a second magnet portion. The first magnet portion is spaced apart from the second magnet portion, and the second magnet portion comprises a bore. In a corresponding sensor device, a sensor element may be provided at a position between the first and second magnet portions.