Pole Wheel Magnetic Position Sensing With Nested PCB Sensor
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Solution Overview
Problem
Magnetic position sensors for rotary machines, such as electric motors, face challenges due to mechanical sensitivity, high manufacturing costs, complexity, and susceptibility to external influences, while optical systems are expensive and sensitive to soiling.
Innovation Solution
A magnetic position sensing system for rotary machines that incorporates a pole wheel with a circumferential magnetic element and position sensors arranged on a printed circuit board, where the sensors extend into the pole wheel's interior space, reducing external interference and improving accuracy by minimizing the distance between the magnetic field and the sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If optical systems are used for position sensing, then measurement precision is improved, but manufacturing cost and device complexity increase
Solution Approach 1:
The patent replaces optical sensing systems with magnetic sensing systems. The magnetic position sensor uses magnetic field detection instead of optical detection, eliminating the need for complex optical components while achieving accurate rotational position sensing. This substitution reduces manufacturing cost and device complexity while maintaining measurement precision.
2Measurement precision
If optical systems are used for position sensing, then measurement precision is improved, but susceptibility to environmental factors worsens
Solution Approach 1:
The patent replaces optical sensing with magnetic sensing, which is not affected by soiling or optical blockage. Magnetic field detection through the pole wheel provides robust position sensing that is immune to environmental factors that plague optical systems, such as dirt, dust, and contamination.
3Ease of manufacture
If magnetic sensors are used for position sensing, then manufacturing cost is reduced, but susceptibility to external magnetic influences worsens
Solution Approach 1:
The patent extracts the magnetic sensor from the general environment and places it in a protected position within the pole wheel structure. The pole wheel with its circumferential edge creates a controlled magnetic environment that isolates the sensor from external magnetic influences while allowing the sensor to detect the rotational position accurately.
Solution Approach 2:
The magnetic sensor is nested within the pole wheel structure, specifically positioned to extend into the space surrounded by the circumferential edge. This nesting provides physical protection and magnetic shielding, reducing susceptibility to external magnetic fields while maintaining sensing capability.
4Measurement precision
If the position sensor is placed close to the magnetic element, then measurement precision is improved, but susceptibility to external influences worsens
Solution Approach 1:
The position sensor is nested within the pole wheel structure, extending into the space surrounded by the circumferential edge. This nesting arrangement places the sensor close to the magnetic element for high precision while simultaneously providing protection from external influences through the structural enclosure.
Solution Approach 2:
The pole wheel structure acts as an intermediary between the magnetic element and the position sensor, and also as a shield between the sensor and external environmental factors. This intermediate structure enables close proximity sensing while reducing susceptibility to external disturbances.
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 accuracy and robustness of rotational position sensing by reducing external disturbances and maintaining the cost-effectiveness of magnetic systems, while allowing for multiturn and digital interface capabilities.
Implementation Method 1
the first position sensor for sensing a change in a magnetic field, and at least one magnetic element being arranged on the pole wheel
Data Source
AI summary
A rotary machine, in particular electric motor, includes a position sensing means for sensing a rotational position of a pole wheel that is rotatable about an axis of rotation. The pole wheel has a circumferential edge, and the position sensing means has at least one first position sensor for sensing a change in a magnetic field, at least one magnetic element arranged on the pole wheel, and at least one circuit card on which electronic components are arranged. The first position sensor is arranged at least indirectly on the circuit card. The first position sensor extends at least partially into a space of the pole wheel that surrounded by the circumferential edge.