Electrically Operated Valve Position Sensing With Fixed Magnet Gap

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Solution Overview

Problem

Existing electrically operated valves face challenges in accurately detecting the angle of rotation of a rotating body using magnetic sensors arranged radially outward, leading to increased costs, complex support mechanisms, and loss of rotational information when power is turned off.

Innovation Solution

An electrically operated valve design featuring a rotor member, stator member, permanent magnet member, and angle sensor, where the guide member guides the relative movement of the rotor member with respect to the permanent magnet member, maintaining a fixed distance between the magnet and sensor, allowing continuous detection of the angle of rotation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If magnetic sensors are arranged radially outward from the rotating body to detect angle of rotation, then the detection mechanism is simplified, but measurement precision deteriorates when multiple sensors are not used

Engineering Contradiction:
Improvedetection mechanism complexityVSAvoidangle of rotation detection precision
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent replaces the conventional radial magnetic sensor arrangement with a Hall effect sensor that detects changes in magnetic field strength along the axial direction. This substitution eliminates the need for multiple radial sensors while achieving precise angle detection through the relationship between magnetic field changes and rotor position.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The invention changes the detection parameter from radial magnetic field position to axial magnetic field strength variation. By detecting how the magnetic field strength changes along the axial direction as the rotor turns, the system achieves precise angle measurement without requiring multiple radial sensors.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If multiple magnetic sensors are arranged radially outward to improve angle detection precision, then measurement precision improves, but device complexity and cost increase

Engineering Contradiction:
Improveangle of rotation detection precisionVSAvoidsupport mechanism complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces multiple radial magnetic sensors with a single Hall effect sensor positioned axially. This substitution dramatically reduces the number of sensors required while maintaining or improving detection precision through the unique axial magnetic field detection method.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The invention extracts only the essential detection function by using a single Hall sensor that detects axial magnetic field changes. This eliminates the need for multiple radial sensors and their complex support structures, achieving the same measurement precision with fewer components.

Inventive Principle:
Principle #2Taking out (Extraction)

3Device complexity

If magnetic sensors detect angle of rotation based on Hall current variations, then the detection mechanism is simple, but information is lost when power is turned off

Engineering Contradiction:
Improvedetection mechanism simplicityVSAvoidabsolute angle of rotation information
Core Design Contradiction:
Device complexityVSLoss of information

Solution Approach 1:

The patent replaces conventional Hall current-based angle detection with a permanent magnet and Hall effect sensor system that detects axial magnetic field strength. This substitution enables absolute position detection that retains information through power cycles, as the magnetic field configuration directly reflects the rotor's absolute angular position.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The permanent magnet provides a continuous magnetic field that serves as its own reference, eliminating the need for external power or reset mechanisms. The Hall sensor detects the magnetic field configuration directly, providing absolute position information that persists without power.

Inventive Principle:
Principle #25Self-service

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 design enables more accurate detection of the valve body position by ensuring precise calculation of the valve opening degree, reducing costs and complexity, and maintaining accurate angle detection even when power is cycled.

Implementation Method 1

a permanent magnet member (70) which turns together with the rotor member (64)

Methodology Applied
Scientific EffectMagnetic field generation: Magnetism

Implementation Method 2

an angle sensor (80) which is arranged above the permanent magnet (72) included in the permanent magnet member (70) and detects an angle of rotation of the permanent magnet (72)

Methodology Applied
Scientific EffectMagnetic field detection: Hall Effect

Data Source

PatentEP3392538B1Electrically operated valve
Publication Date: 2019.12.25 FUJIKOKI CORP
  • EP3392538B1 patent drawingFigure 1
  • EP3392538B1 patent drawingFigure 2
  • EP3392538B1 patent drawingFigure 3A~3B

AI summary

The invention provides an electrically operated valve which can more accurately detect a position of a valve body. An electrically operated valve is provided with a valve shaft, a valve body, a rotor member which is movable together with the valve shaft in a parallel direction to a first direction, a stator member which applies a turning force to the rotor member, a permanent magnet member which turns together with the rotor member, an angle sensor which detects an angle of rotation of the permanent magnet, and a guide member which guides a relative movement of the rotor member or the valve shaft in relation to the permanent magnet member. A distance between the permanent magnet and the angle sensor is fixed when the permanent magnet member turns.