Triangular Sensor Arrangement for Rotational Direction Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional rotary sensors face challenges in accurately determining the direction of rotation and require complex calibration and alignment, leading to time-consuming and error-prone installation processes, especially when the two Hall elements have the same distance to the next tooth, resulting in measurement inaccuracies.
Innovation Solution
A sensor arrangement with at least three offset magnetic field sensors, arranged in a triangular configuration, ensures that each projection interacts with the sensors at different times, allowing for the determination of direction of rotation regardless of installation position, eliminating the need for precise alignment and enabling quick assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If two Hall elements are used for speed detection, then the rotational speed can be determined, but the direction of rotation cannot be determined when both Hall elements have the same distance to the next tooth
Solution Approach 1:
The patent divides the detection function into three separate magnetic field sensors instead of using two Hall elements. This segmentation allows each sensor to independently detect magnetic field changes, and by comparing the detection times across three sensors, the system can reliably determine rotation direction without requiring precise alignment, thus resolving the contradiction between measurement precision and reliability
Solution Approach 2:
The patent transitions from a linear arrangement of two sensors to a two-dimensional triangular arrangement of three sensors. This dimensional change ensures that at least one sensor will always have a different distance to the nearest tooth, providing the necessary time offset for direction detection and eliminating the reliability issue when sensors are equidistant
2Measurement precision
If two Hall elements are offset in the direction of rotation, then the direction of rotation can be determined, but complex calibration and alignment are required during installation
Solution Approach 1:
The triangular arrangement of three magnetic field sensors is designed to be self-aligning during installation. The geometry ensures that regardless of the exact mounting position, at least one pair of sensors will have different distances to the nearest tooth, automatically providing the necessary time offset for direction detection without requiring manual calibration or alignment by the installer
Solution Approach 2:
The patent uses an asymmetric triangular configuration of three sensors instead of a symmetric linear arrangement. This asymmetry ensures that the sensors naturally occupy different radial positions relative to the rotating component, guaranteeing that at least one sensor will detect magnetic field changes at a different time, thereby eliminating the need for precise alignment during installation
3Manufacturing precision
If the two Hall elements have the same distance to the flank of the next tooth, then the magnetic field strength at both sensors is the same, but this leads to measurement inaccuracies and requires time-consuming readjustment
Solution Approach 1:
By segmenting the detection function across three magnetic field sensors arranged in a triangle, the patent ensures that not all sensors will simultaneously be equidistant from the nearest tooth. This segmentation eliminates the need for precise alignment to avoid equidistant conditions, as the geometric probability of all three sensors being equidistant is zero, thus eliminating time-consuming readjustment during installation
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 solution ensures accurate measurement of rotational speed and direction of rotation without complex calibration, as the offset sensors always have different distances from the nearest projection, improving measurement accuracy and simplifying the installation process.
Implementation Method 1
Speed sensors equipped with a magnetic field sensor (e.g. Hall sensor) are usually used for non-contact speed detection. A magnet generates a magnetic field in the area of the Hall sensors, which changes when a tooth of the gear wheel is passed.
Implementation Method 2
Speed sensors equipped with a magnetic field sensor (e.g. Hall sensor) are usually used for non-contact speed detection
Data Source
Figure 1A~1B
Figure 2A~2B
Figure 3
AI summary
The invention relates to an arrangement for the non-contact determination of the rotational speed and direction of rotation of a component rotating during operation, in particular a magnetizable shaft. The arrangement comprises a component (7) rotating during operation, which has a circumferential structure on at least one circumferential region consisting of radial projections (S) shaped like webs or teeth and grooves (N) or tooth gaps located between them. The arrangement further comprises a screwable sensor device (1) for determining the rotational speed and direction of rotation of the component (7), having a threaded section (3) for the stationary mounting of the sensor device (1), so that the circumferential structure can be moved past the sensor device, a magnetic field generation device, and a magnetic field detection device.The magnetic field detection device comprises at least three magnetic field sensors (6_1, 6_2, 6_3) that are not aligned along a line, with the distance between the most distant magnetic field sensors being less than or equal to the width (d_N) of the grooves (N) or tooth gaps. This prevents all sensors from simultaneously registering a transition from tooth to tooth gap, and ensures that, regardless of the sensor's rotational position about its longitudinal axis, two sensors can always be identified that are at their maximum distance from each other in the direction of movement of the rotating component. These two sensors are then evaluated to determine the direction of rotation. The sensors are arranged in a plane perpendicular to the radial direction of the rotating component.