Rotation Speed Detector Non-Magnetic Gap Vibration
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Solution Overview
Problem
Existing rotation speed detectors can erroneously detect rotation of a rotating body when it vibrates in the rotation direction, due to sudden changes in the magnetic field applied to the power generation element.
Innovation Solution
A rotation speed detector design that includes a non-magnetic base material attached to a rotating body, with first and second magnetic poles of arcuate strip shape and a power generation element configured to face these poles, featuring a non-magnetic gap between the magnetic poles to prevent false detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the first magnetic pole portion and the second magnetic pole portion are arranged adjacent to each other with no gap, then the device structure is simplified and compact, but the magnetic field direction switches suddenly causing erroneous rotation detection during vibration
Solution Approach 1:
A non-magnetic gap is introduced between the first magnetic pole portion and the second magnetic pole portion. This gap acts as an intermediary that prevents direct magnetic field interaction between the two poles, thereby avoiding sudden magnetic field direction switches that cause erroneous detection during vibration.
2Measurement precision
If the magnetic pole portion facing the power generation element is switched from one pole to the other, then rotation speed detection is enabled, but the sudden magnetic field direction switching causes false detection during vibration
Solution Approach 1:
The non-magnetic gap serves as a mediator that allows the magnetic pole switching function for rotation detection while preventing the harmful sudden magnetic field transitions that occur during vibration, thus maintaining detection precision while improving reliability.
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 proposed design effectively reduces the likelihood of erroneous rotation detection even when the attached rotating body vibrates in the rotation direction, by smoothing the magnetic field changes and preventing power generation pulses during minor vibrations.
Implementation Method 1
a power generation element including a magnetic wire configured to cause a large Barkhausen effect, and a pickup coil configured to detect magnetization reversal of the magnetic wire
Data Source
AI summary
A rotation speed detector includes: a base material to be attached to a rotating body; a first magnetic pole having an arcuate strip shape and provided on the base material; a second magnetic pole having an arcuate strip shape and provided on the base material; and a power generation element including a magnetic wire configured to cause a large Barkhausen effect, and a pickup coil. The power generation element is arranged to face the first magnetic pole and the second magnetic pole so that a longitudinal direction of the magnetic wire is provided along a radial direction of the first magnetic pole and the second magnetic pole. A non-magnetic gap is provided between the first magnetic pole and the second magnetic pole.