Rotation Direction Detection Using Multi-Element Magnetic Sensor
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional proximity detectors for ferromagnetic objects can detect rotation speed but not the direction of rotation, leading to incomplete information in rotational monitoring applications.
Innovation Solution
A rotation detector system that includes a magnetic field sensor and detector circuits generating output signals with rising and falling edges, where the output protocol circuit produces signals indicative of both the speed and direction of rotation using pulse patterns or pulse counts differing by direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional proximity detectors are used to detect rotation speed, then the speed of rotation can be detected, but the direction of rotation cannot be determined
Solution Approach 1:
The magnetic field sensor is divided into multiple sensing elements arranged in a specific pattern around the rotation axis. Each sensing element detects magnetic field changes at different positions, and by comparing the timing and phase of signals from different elements, the system can determine both rotation speed and direction. This segmentation of the sensing function enables extraction of directional information that was previously unavailable.
Solution Approach 2:
The patent transitions from detecting only the magnitude of magnetic field changes (one-dimensional) to detecting both magnitude and phase/timing relationships across multiple sensor elements (multi-dimensional). By adding the spatial dimension of multiple sensor positions and analyzing the temporal relationships between their outputs, the system recovers directional information without sacrificing speed measurement capability.
2Loss of information
If multiple detector circuits are used to detect both speed and direction, then comprehensive rotational data is provided, but device complexity increases
Solution Approach 1:
The magnetic field sensor serves multiple functions simultaneously: it detects rotation speed through frequency analysis of the magnetic field signal and determines rotation direction through phase comparison across sensor elements. This multi-functionality is achieved within a single integrated sensor assembly, avoiding the need for separate speed and direction detection systems, thereby reducing overall device complexity while providing comprehensive rotational data.
Solution Approach 2:
The patent combines speed detection and direction detection functions into a unified detection system using a single magnetic field sensor with multiple sensing elements. The output signals from all elements are processed together through a single protocol circuit that simultaneously extracts both speed and direction information, merging what would traditionally require separate detection systems into one integrated solution.
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 system effectively communicates the speed and direction of rotation of ferromagnetic objects, enhancing monitoring capabilities by providing comprehensive rotational data.
Implementation Method 1
the magnetic field associated with the ferromagnetic is detected by a magnetic field-to-voltage transducer (also referred to herein as a magnetic field sensing element), such as a Hall effect element
Implementation Method 2
the magnetic field associated with the ferromagnetic is detected by a magnetic field-to-voltage transducer (also referred to herein as a magnetic field sensing element), such as a Hall effect element or a magnetoresistance element
Data Source
Figure 1
Figure 2
Figure 3
AI summary
An apparatus and a method provide an output signal indicative of a speed of rotation and a direction of rotation of a ferromagnetic object capable of rotating. A variety of signal formats of the output signal are described.