Rotation Angle Detection Stabilizing Magnet-Sensor Distance

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Solution Overview

Problem

Existing rotation angle detection techniques using magnetic sensors face accuracy issues when the rotating body both rotates and moves along its axis, as changes in distance between the sensor and magnet affect signal output, leading to decreased detection accuracy.

Innovation Solution

A rotation angle detection device comprising a support body, a rotating body with a rotation axis, a magnet, a magnetic sensor, and a position detection unit that ensures the rotating body is at a predetermined distance from the sensor, allowing accurate determination of the rotation angle from the sensor's output signal.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the rotating body moves in the rotation axis direction, then the versatility of the detection system is improved, but the measurement precision of the rotation angle deteriorates

Engineering Contradiction:

Improvecapability to detect rotation angle while rotating body moves along rotation axisVSAvoidrotation angle detection accuracy

Core Design Contradiction:

Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent replaces mechanical distance fixation mechanisms with a magnetic field-based detection system. A magnet is attached to the rotating body and a magnetic sensor is positioned at a predetermined distance to detect rotation angle through magnetic field changes, eliminating the need for mechanical constraints while maintaining measurement precision despite axial movement

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent utilizes changes in magnetic field parameters (strength and direction) as the magnet rotates, allowing the magnetic sensor to detect rotation angle through these parameter variations. This enables accurate rotation detection regardless of the rotating body's position along the rotation axis, as long as the magnet-sensor distance remains predetermined

Inventive Principle:

Principle #35Parameter changes

2Adaptability or versatility

If the distance between the magnetic sensor and the magnet changes, then the adaptability to different positions is improved, but the measurement precision of the rotation angle deteriorates

Engineering Contradiction:

Improveability to operate at different sensor-magnet distancesVSAvoidrotation angle detection accuracy

Core Design Contradiction:

Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent establishes the magnetic sensor at a predetermined distance from the magnet before rotation detection begins. This preliminary positioning ensures optimal magnetic field interaction and accurate rotation angle measurement, preventing distance-related precision degradation while maintaining system adaptability

Inventive Principle:

Principle #10Preliminary action

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 configuration enhances the accuracy of rotation angle detection by stabilizing the distance between the magnet and sensor, effectively mitigating the impact of distance variations and ensuring precise angle determination.

Implementation Method 1

a magnetic sensor attached to the other of the support body and the rotating body and facing the magnet in the rotation axis direction, and that detects a rotation angle of the rotating body with respect to the support body on the basis of an output signal of the magnetic sensor

Methodology Applied

Scientific EffectMagnetic field: Magnetic Field

Data Source

PatentEP2511663B1Rotation angle detection device, rotation angle detection method, and part mounting apparatus

Publication Date: 2015.06.03 YAMAHA MOTOR CO LTD

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AI summary

A rotation angle detection device of the present invention includes: a support body; a rotating body that can rotate with respect to the support body about a rotation axis and move in a rotation axis direction; a rotation angle detection unit that has a magnet attached to either of the support body and the rotating body, and a magnetic sensor attached to the other of the support body and the rotating body and facing the magnet in the rotation axis direction, and that detects a rotation angle of the rotating body on the basis of an output signal of the magnetic sensor; and a position detection unit that detects that the rotating body is positioned at a detection position in which a distance between the magnet and the magnetic sensor in the rotation axis direction becomes a predetermined detection distance. The rotation angle detection unit reads the output signal of the magnetic sensor and determines the rotation angle of the rotating body with respect to the support body from the output signal when the position detection unit detects that the rotating body is positioned at the detection position.