Vibration Sensor With Segmented Converter And Air Gap

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Solution Overview

Problem

Existing vibration sensors with converter devices using excitation coils and bolts or magnets suffer from limited magnetic force due to stray fields and are not suitable for high-temperature applications.

Innovation Solution

A vibration sensor design featuring a two-part converter device with a permanent magnet and coil core, an air gap, and a magnetic yoke to enhance driving force, while minimizing stray fields, and using heat-treated materials for high-temperature stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If a conventional coil core is used in the converter device, then the structure is simple, but the driving force is limited due to stray fields

Engineering Contradiction:
Improvedriving forceVSAvoidconverter device structure
Core Design Contradiction:
ForceVSDevice complexity

Solution Approach 1:

The converter device is divided into two separate parts: a permanent magnet unit and a coil core unit, connected through an air gap. This segmentation allows the permanent magnet to provide a strong static magnetic field while the coil generates dynamic magnetic forces, achieving high driving force while managing stray fields through the air gap configuration

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The converter device combines two different magnetic components (permanent magnet and electromagnet/coil core) with complementary characteristics. The permanent magnet provides high remanence and stable magnetic field, while the coil provides controllable dynamic magnetic force, creating a composite magnetic system with superior overall performance

Inventive Principle:
Principle #40Composite materials

2Temperature

If standard materials are used in the vibration sensor, then the manufacturing is easier, but the sensor is not suitable for high temperatures

Engineering Contradiction:
Improveoperating temperature rangeVSAvoidfrequency stability
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

The oscillating element is subjected to heat treatment that changes its physical parameters, specifically reducing internal stresses and stabilizing its dimensional properties. This heat treatment modifies the material's thermal response characteristics, enabling the element to maintain stable resonant frequency across a wide temperature range from -40°C to +150°C

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent addresses thermal expansion effects through heat treatment of the oscillating element, which stabilizes the material's dimensional properties. The heat treatment process modifies the material's thermal response, reducing thermal hysteresis and ensuring that dimensional changes due to temperature variations do not significantly affect the resonant frequency

Inventive Principle:
Principle #37Thermal expansion

3Object-generated harmful factors

If a conventional converter device is used, then the structure is compact, but stray fields are generated inside and outside the sensor

Engineering Contradiction:
Improvestray fieldsVSAvoiddriving force
Core Design Contradiction:
Object-generated harmful factorsVSForce

Solution Approach 1:

The harmful stray fields are effectively 'taken out' or isolated by introducing an air gap between the permanent magnet and coil core. This air gap acts as a magnetic insulator that contains the magnetic flux within the converter device, preventing stray fields from extending outside the sensor while maintaining the strong magnetic interaction needed for high driving force

Inventive Principle:
Principle #2Taking out (Extraction)

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 achieves a higher driving force and reduced stray fields, making the vibration sensor suitable for high-temperature operations with improved frequency stability and minimized thermal hysteresis.

Implementation Method 1

the permanent magnet and the excitation coil being arranged to interact in such a way that an oscillation of the permanent magnet induces a current flow in the excitation coil and/or a magnetic field inducing current flow in the excitation coil causes a vibration of the permanent magnet

Methodology Applied
Scientific EffectElectromagnetic interaction: Lorentz Force

Implementation Method 2

an oscillation of the permanent magnet induces a current flow in the excitation coil and/or a magnetic field inducing current flow in the excitation coil causes a vibration of the permanent magnet

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP2209110B1Vibration sensor
Publication Date: 2013.09.25 VEGA GRIESHABER GMBH & CO
  • EP2209110B1 patent drawingFigure 1~2
  • EP2209110B1 patent drawingFigure 3~4

AI summary

Vibration sensor (1) with a support element that can be set into vibration, a transducer device (3) having an excitation coil (2) for setting the support element (5) into vibration and/or for picking up a vibration of the support element (5), a bolt mounted in the excitation coil (2), a vibration element (6) and/or a support element (5) designed as a vibration element for transmitting the vibrations from the support element (5) into a surrounding space and/or from a surrounding space to the support element (5).According to the invention, the bolt is formed in two parts with a permanent magnet (7) and a coil core (8) connected to the excitation coil (2), wherein an air gap (9) arranged between the permanent magnet (7) and the coil core (8) lies in the region of the axial extent of the excitation coil (2), furthermore the permanent magnet (7) is connected to the support element (5) for the transmission of the vibrations, and the excitation coil (2) and the permanent magnet (7) are arranged to interact in such a way that an oscillation of the permanent magnet (7) is induced and/or a current flow in the excitation coil (2) inducing a magnetic field causes an oscillation of the permanent magnet (7).