CN101609131A - Magnetostrictive material, high magnetic permeability material and quartz tuning fork composite magnetic sensor - Google Patents

Abstract

The invention discloses a composite magnetic sensor of a magnetostrictive material, a high magnetic permeability material and a quartz tuning fork. The PZT piezoelectric micro-displacement device is fixed on the inside of the vertical arm of the "L"-shaped base; the bracket is fixed on the magnetostrictive material block, and the magnetostrictive material block is fixed on the transverse arm of the "L"-shaped base; on the bracket A magnetic material sheet is provided, and one of the vibrating arms of the quartz tuning fork is provided with a magnetic material sheet on a plane close to the side of the bracket. The magnetic material sheet on the bracket and the magnetic material sheet on the vibrating arm are parallel to each other in planes, face to face, and match in size. The beneficial technical effect of the invention is that it provides a composite structure magnetic sensor with higher magnetoelectric conversion coefficient and relatively higher sensitivity.

Description

Magnetostrictive material, high magnetic permeability material and quartz tuning fork composite magnetic sensor

technical field

The invention relates to a magnetic sensing technology, in particular to a composite magnetic sensor of a magnetostrictive material, a high magnetic permeability material and a quartz tuning fork.

Background technique

At the end of the last century, people began to study the composite laminated structure of magnetostrictive materials and piezoelectric materials. This composite structure does not require power excitation and is small in size. It is a very potential magnetic measuring device. For example, US patent 20010028245A1 proposes a magnetoelectric composite structure combining magnetostrictive materials and ferroelectric materials, and also studies a composite structure using piezoelectric resistance materials and magnetostrictive materials, giving the structure two piezoelectric resistances. A constant current is input to the terminal. Due to the deformation of the piezoelectric material in the magnetic field, the resistance of the composite piezoelectric resistance material is changed. By observing and comparing the output voltage of the piezoelectric resistance material, the size of the external magnetic field can be estimated. US patent 20020135364A1 proposes a measurement method for a magneto-impedance sensor. The sensor generates a bias magnetic field when it is energized, and at the same time, magnetostriction generates stress. Under different stress and magnetic field conditions, the impedance of the sensing unit changes differently. By measuring the change in impedance, the magnetic field can be measured. However, due to the limitation of the characteristics of magnetostrictive materials and piezoelectric/ferroelectric materials, the corresponding magnetic sensitivity is also low.

The magnetoelectric coefficient of the laminated composite structure of magnetostrictive material and piezoelectric material is proportional to its quality factor, and the quality factor of both magnetostrictive material and piezoelectric material is relatively low (about 100), so it is necessary to improve the quality factor of the composite structure. The figure of merit is an effective way to improve the magnetoelectric conversion coefficient.

Contents of the invention

The invention proposes a magnetostrictive material, a high magnetic permeability material and a quartz tuning fork composite magnetic sensor, which includes: a quartz tuning fork, an "L"-shaped base, a PZT piezoelectric micro-displacement device, a micro-motion stage, a magnetostrictive Material blocks, brackets, and magnetic material sheets; quartz tuning forks are fixed on the micro-motion table, the micro-motion table is fixed on the PZT piezoelectric micro-displacement device, and the PZT piezoelectric micro-displacement device is fixed on the inside of the vertical arm of the "L"-shaped base The bracket is fixed on the magnetostrictive material block, and the magnetostrictive material block is fixed on the transverse arm of the "L"-shaped base; the bracket is provided with a magnetic material sheet, and one of the vibrating arms of the quartz tuning fork is close to the side of the bracket. A magnetic material sheet is arranged on the plane, and the magnetic material sheet on the bracket and the magnetic material sheet on the vibrating arm are parallel to each other in planes, face to face, and match in size.

The beneficial technical effect of the invention is that it provides a composite structure magnetic sensor with higher magnetoelectric conversion coefficient and relatively higher sensitivity.

Description of drawings

Fig. 1, structure of the present invention;

Detailed ways

How can the quality factor of composite structures be improved? The inventor turned his attention to the quartz material: the quartz tuning fork 1 made of quartz material has a very high quality factor, and the quality factor of the sealed quartz tuning fork 1 can reach more than hundreds of thousands, even if the quartz tuning fork 1 exposed in the air , and its quality factor is about 10,000. Therefore, combining the quartz tuning fork 1 with the composite structure of the magnetostrictive material can increase the magnetoelectric coefficient, thereby improving the sensitivity of the magnetic sensor with the composite structure.

Based on the foregoing theoretical analysis, and aiming at specific problems in practical applications, the inventor proposes the structure of the present invention. In addition to introducing the quartz tuning fork 1 into the sensor structure, the present invention also designs the positions and connecting parts between the various components of the sensor very well. Precision, so that the vibration parameters of the quartz tuning fork 1 will automatically change with the change of the external magnetic field. This design further improves the sensitivity of the sensor.

The following explains its principle through its structural characteristics:

The transverse arm of " L " type base 2 links to each other with magnetic material sheet 7 by magnetostrictive material piece 5 and support 6, and the setting position of support 6 and shape, size can be adjusted artificially, and the principle of adjustment is: make on the support 6 The magnetic material sheet 7 is opposite to the magnetic material sheet 7 on the quartz tuning fork 1. This structure makes: when the external magnetic field changes, the magnetostrictive material block 5 drives the bracket 6 to change the distance between the two magnetic material sheets 7, thereby changing the two magnetic materials. The magnitude of the interaction force of the material sheet 7 can significantly change the resonance frequency, amplitude and quality factor of the quartz tuning fork 1 , making the quartz tuning fork 1 more sensitive to changes in the external magnetic field.

The quartz tuning fork 1 is connected to the inner side of the vertical arm of the "L"-shaped base 2 through the micro-table 4 and the PZT (piezoelectric ceramic) piezoelectric micro-displacement device 3. The PZT piezoelectric micro-displacement device 3 perceives the quartz tuning fork 1 The "mechanical-electrical" conversion part of the magnetic field change into electrical output, due to the change of the external magnetic field, the length of the magnetostrictive material block 5 changes, and the magnetostrictive material block 5 drives the support 6, thereby changing the connection between the support 6 and the quartz tuning fork. The distance between the two magnetic material sheets 7 on 1 changes the force between them, and the resonant frequency, amplitude and quality factor of the quartz tuning fork 1 also change. By detecting the electrical output of the quartz tuning fork 1, it can be measured The change value of resonant frequency, amplitude and quality factor can realize the purpose of sensing.

It should be noted that the relative position of the quartz tuning fork 1 and the "L" type base 2 can have various forms, and the position of the magnetic material sheet 7 on the quartz tuning fork 1 can also have multiple options, and its ultimate purpose is to make The magnetic material sheet 7 on the support 6 is opposite to the magnetic material sheet 7 on the quartz tuning fork 1 (facilitating the application of force), such as: the two vibrating arms of the quartz tuning fork 1 can follow the transverse arm of the "L" type base 2 Secondary arrangement; two vibrating arms can also be arranged side by side along the transverse arm of the "L"-shaped base 2; the quartz tuning fork 1 can also be placed flat, and the "L"-shaped A cantilever is formed on the vertical arm of the base 2; for the relative positions of the aforementioned three kinds of quartz tuning forks 1 and the "L" type base 2, the magnetic material sheet 7 on the quartz tuning fork 1 can be respectively arranged on one of the tuning forks to vibrate The outside of the arm, the side of the "U" shape of the tuning fork on the vibrating arm, and the end face of the vibrating arm can be specifically designed according to the sensor size, shape and other conditions.

Example:

Referring to Fig. 1, taking the setting method in which the two vibrating arms of the quartz tuning fork 1 are arranged sequentially along the transverse arm of the "L"-shaped base 2 as an example, the quartz tuning fork 1 is fixed on the micro-motion table 4, and one end of the micro-motion table 4 is fixed On one side of the PZT piezoelectric micro-displacement device 3, the other side of the PZT piezoelectric micro-displacement device 3 is fixed on the inside of the vertical arm of the "L" type base 2; the bracket 6 is fixed on one end of the magnetostrictive material block 5, and the magnetic The other end of the stretchable material block 5 is fixed on the outer end of the lateral arm of the "L"-shaped base 2; the position where the upper end of the support 6 matches the magnetic material sheet 7 on the tuning fork is provided with a magnetic material sheet 7, and the quartz tuning fork 1 wherein A vibrating arm is provided with a magnetic material sheet 7 on the plane near the side of the support 6, and the magnetic material sheet 7 on the support 6 and the magnetic material sheet 7 on the vibrating arm are parallel in plane, face to face, and match in size.

If the arrangement of the quartz tuning fork 1 in which the two vibrating arms extend along the transverse arm of the "L"-shaped base 2 is used, the difference between it and the structure described in the previous paragraph is that the two vibrating arms of the quartz tuning fork 1 extend "L" The extension direction of the transverse arm of the "type base 2 is juxtaposed. At this time, a vibrating arm can be selected, and a magnetic material sheet 7 is arranged on the side of the "U" surface of the tuning fork on the vibrating arm, and the bracket 6 and the magnetic material are adjusted. The relative position between the stretchable material blocks 5 is such that the magnetic material sheet 7 on the bracket 6 and the magnetic material sheet 7 on the vibrating arm are parallel to each other in planes, face to face, and match in size.

If adopt the arrangement mode that quartz tuning fork 1 lays flat, it differs from the previous two mechanisms in that the magnetic material sheet 7 is arranged on the end (i.e. end face) of any vibrating arm, and the magnetic material sheet 7 faces opposite to each other. The relative position between the bracket 6 and the magnetostrictive material block 5 is adjusted according to the conditions.

Claims (1)

1, a kind of magnetostriction materials, high-permeability material and quartz tuning fork compound magnetic sensor, it is characterized in that: it comprises: quartz tuning-fork (1), " L " type pedestal (2), PZT piezoelectric actuator (3), micropositioner (4), magnetostriction materials piece (5), support (6), magnetic material sheets being (7); Quartz tuning-fork (1) is fixed on the micropositioner (4), and micropositioner (4) is fixed on the PZT piezoelectric actuator (3), and PZT piezoelectric actuator (3) is fixed on the vertical arm inboard of " L " type pedestal (2); Support (6) is fixed on the magnetostriction materials piece (5), and magnetostriction materials piece (5) is fixed on the transverse arm of " L " type pedestal (2); Support (6) is provided with magnetic material sheets being (7), be provided with magnetic material sheets being (7) near the plane of that side of support (6) on the wherein shaker arm of quartz tuning-fork (1), relative, the size match of magnetic material sheets being (7) plane parallel on magnetic material sheets being (7) on the support (6) and the shaker arm and front.

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