Rotation Speed Sensor Magnetic Plate Air Gap Design
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Solution Overview
Problem
Existing rotation speed sensors face challenges in maintaining measurement accuracy while achieving a large air gap, which is desirable for ease of attachment and design flexibility.
Innovation Solution
A rotation speed sensor design incorporating a sensor component with two magnetic sensing elements and a magnet, where a magnetic plate with an opening is positioned between the sensor component and the magnet to enhance magnetic flux density and allow for a larger air gap without compromising accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a small air gap is used between the sensor component and the workpiece, then measurement accuracy is improved, but ease of attachment and design flexibility deteriorate
Solution Approach 1:
A magnetic plate is introduced as an intermediary component between the sensor component and the workpiece. The magnetic plate includes a through-hole that allows magnetic flux to be concentrated toward the magnetic sensing element, enabling the sensor to accurately sense magnetic field changes even when a large air gap is present. This mediator resolves the contradiction by decoupling the attachment distance from the measurement accuracy requirement.
Solution Approach 2:
The invention changes the magnetic circuit parameters by introducing a magnetic plate with specific magnetic permeability and a through-hole structure. This modifies the magnetic flux distribution, concentrating the flux lines through the opening toward the sensing element. The parameter change in magnetic flux density distribution enables accurate measurement despite increased air gap distance.
2Measurement precision
If a small air gap is used between the sensor component and the workpiece, then measurement accuracy is improved, but design flexibility deteriorates
Solution Approach 1:
The magnetic plate serves as a mediator that actively manages magnetic flux distribution. The through-hole in the magnetic plate creates a preferential path for magnetic flux, concentrating it toward the magnetic sensing element. This allows the sensor design to accommodate various air gap sizes without compromising measurement accuracy, thereby improving adaptability to different installation scenarios.
Solution Approach 2:
The magnetic plate introduces local quality variation in the magnetic circuit by creating a concentrated flux path through the through-hole. The magnetic flux density is locally enhanced in the region of the opening, ensuring that the magnetic sensing element receives sufficient magnetic signal even when positioned at a greater distance from the workpiece. This local enhancement enables design flexibility while maintaining measurement precision.
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 design effectively increases the air gap between the sensor and the workpiece, improving measurement accuracy and simplifying attachment while maintaining necessary sensing precision.
Implementation Method 1
a magnetic plate arranged between the second surface of the sensor component and the magnet and made of a magnetic material. The magnetic plate includes an opening formed in a first direction
Implementation Method 2
a magnet arranged in a region closer to the second surface of the sensor component
Implementation Method 3
a first magnetic sensing element arranged between the first surface and the second surface, and a second magnetic sensing element arranged between the first surface and the second surface so as to separate from the first magnetic sensing element
Data Source
AI summary
An air gap of a rotation speed sensor is increased. A rotation speed sensor according to one embodiment includes: a sensor component having magnetic sensing elements; and a magnetic plate that is arranged between the sensor component and a magnet and that is made of a magnetic material. In a first direction that is a direction in which the sensor component, the magnetic plate and the magnet are arranged, the magnetic plate includes an opening that is formed at a position overlapping center of a line connecting respective centers of the magnetic sensing elements.