Electromagnetic Actuator Hall Sensor Layout Against Inductor Interference
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Solution Overview
Problem
Existing electromagnetic actuator measurement modules, particularly those using Hall effect sensors, are hindered by the strong magnetic field produced by the inductor, leading to reduced detection capacity and reliability.
Innovation Solution
The integration of a magnetic field sensor with a permanent magnet system, where the sensor's direction of sensitivity is perpendicular to the radial plane in which it is positioned, allowing it to operate effectively despite the powerful magnetic field of the inductor, and enabling detection of armature and drive disc parameters such as displacement, rotation, and torque.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a magnetic field sensor (Hall effect sensor) is used to measure armature displacement, then contactless measurement is achieved, but the sensor detection capacity is strongly disturbed by the powerful magnetic field of the inductor
Solution Approach 1:
The patent applies local quality by creating a localized magnetic environment for the sensor that is distinct from the inductor's magnetic field. A magnetic shield is positioned between the inductor and the Hall effect sensor to block or redirect the inductor's magnetic field lines, while allowing the sensor to detect the magnetic field generated by the permanent magnet attached to the armature. This selective shielding preserves sensor detection capacity while protecting it from the disturbing inductor field.
Solution Approach 2:
The patent introduces a magnetic shield as an intermediary element between the inductor and the magnetic field sensor. This shield acts as a mediator that selectively interacts with different magnetic fields: it blocks the strong alternating magnetic field from the inductor while allowing detection of the magnetic field from the permanent magnet on the armature. The shield thus enables the sensor to function reliably without direct exposure to the disturbing magnetic field.
2Measurement precision
If golden contacts are used for mechanical sensor measurement, then direct electrical contact is achieved, but the contacts are excessively sensitive to pollution and deteriorate
Solution Approach 1:
The patent replaces the mechanical contact-based measurement system (golden contacts) with a contactless magnetic field sensing system using a Hall effect sensor. The permanent magnet attached to the armature generates a magnetic field that varies with armature position, which is detected by the Hall effect sensor without any physical contact. This substitution eliminates wear and pollution issues associated with mechanical contacts while maintaining measurement accuracy.
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 the magnetic field sensor is minimally disturbed by the inductor's field, providing reliable and accurate measurements of armature and drive disc parameters, including displacement, speed, and torque, while maintaining operational insensitivity to the inductor's magnetic interference.
Implementation Method 1
The actuator also comprising a measurement module comprising a magnetic field sensor, such as a Hall effect sensor, arranged in a radial plane Pr and defining a direction of sensitivity B to magnetic fields, the measurement module comprising at least one permanent magnet which moves relative to the magnetic field sensor so as to generate a magnetic field detectable by the magnetic field sensor
Implementation Method 2
a magnetic field sensor, such as a Hall effect sensor, arranged in a radial plane Pr and defining a direction of sensitivity B to magnetic fields
Implementation Method 3
when the inductor is supplied with current, the armature is moved, by electromagnetic attraction, towards the inductor against the elastic means
Data Source
Figure 1~2
Figure 3a~3b
Figure 4~5b
AI summary
Electromagnetic actuator comprising at least one inductor (I), an armature (A), a driving disc (D) and an elastic pressurising means, and at least one measuring module comprising a magnetic field sensor (3), such as a Hall effect sensor, arranged in a radial plane Prv and defining a direction of sensitivity B to the magnetic fields, the measuring module (H) comprising at least one permanent magnet (42, 43) which moves relative to the magnetic field sensor (3) so as to generate a magnetic field detectable by the magnetic field sensor (3), characterised in that the sensitivity direction B of the magnetic field sensor (3) is perpendicular to the radial plane Prv wherein the magnetic field sensor (3) is positioned.