SU1383115A2 - Tensile force magnetoelastic sensor - Google Patents

Abstract

This invention relates to a technique for measuring forces and pressures. The purpose of the invention is to increase accuracy and sensitivity by eliminating the air gap and ensuring that the characteristic does not depend on the sign of the measured force, as well as to increase the functional capabilities by providing pressure measurement. A rectangular section element 6 made of magnetic elastic material is inserted into the gap of the magnetic circuit 1 of the magneto-optic sensor, and its large sides are fastened to the end ends of the magnetic flux 1. 4 Il. Q S

Description

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The invention relates to a technique for measuring forces and pressures and is an improvement of the invention according to the author. No. 52761I.

The purpose of the invention is to increase accuracy and sensitivity by eliminating the air gap and ensuring the independence of the characteristic from the sign of the measured force, as well as expanding the functional possibilities by providing pressure measurement.

Figures I and 2 show projections of the proposed magnetoelastic tensile force sensor with an annular magnetic circuit; on fig.Z - the converter of efforts and. pressure with a frame magnetic conductor; Fig. 4 is a circuit for replacing the magnetic circuits of the transducers.

The magnetoelastic sensor (ig, 1-3) contains a closed magnetic circuit 1 with bending symmetrical arms 2, on which holes 3 are made. The differentially connected measuring windings 4 are placed in holes 3 and cover the outer and inner parts of the magnetic circuit 2 from the neutral line of the magnetic circuit. The magnetizing winding 55, fed by alternating current, is placed between the arms 2 and covers the magnetic circuit i in thickness. The torus arms 2 are closed between each other by a flexible magnetic core 1 bent as an element 6 made of two rectangular elastic plates 7 interconnected on short sides and arranged perpendicularly to the center line of the magnetic conductor, while the sizes of the plates 7 exceed the dimensions of the transverse magnetic field section 1.

In the circuit of the magnetic circuit (Fig. 4), there is an aggressive resistance of a section of each shoulder outside the neutral line; RM is the magnetic resistance of €; but not inside of the neutral line of the section of each shoulder 2; R is the magnetic resistance of the walls of each half of the element 6, which closes the ends of the shoulders 2 on either side of the neutral line 5 Rg- - mag1-piece air resistance between the ends of the shoulders 2 f w is the magnetomotive force of the magnetizing winding 5.

The sensor works as follows

In the absence of a measurable force P (or pressure), the external and internal

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from the neutral line, the parts of the shoulders 2 have the same magnetic resistances RU R ... Therefore, the components

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The magnetic flux of these sections (along the contours, F and are equal to each other, therefore, at the differential output of the measuring windings 4, the voltage is zero.

When exposed to a measured tensile force P between the ends of the arms 2 (or pressure), the walls of the element 6 are bent to the side of the ends of the arms 2 from each other. In this case, the areas of the arms 2 that are external from the neutral line are compressed, therefore the magnetic resistances R, and the magnetic fluxes of these areas decrease. At the same time, the inner regions of the arms 2 from the neutral line are stretched, and the magnetic resistances Rjij J of these areas decrease, and the magnetic fluxes through them increase. As a result, a voltage appears in the differential output of the measuring windings 4, which is proportional to the measured force (pressure) and due to the difference in magnetic fluxes along the outer and inner parts of the shoulders 2 with magnetic resistances R / ift, RMJ The sensor works in a similar way when subjected to compressive force between the ends of the shoulders 2.

When measuring the pressure, the ends of element 6 are rigidly and tightly connected to the system pipeline (for example, by welding), the pressure in which is necessary to determine. Therefore, the walls of element 6 operate as rectangular membranes with pinched edges, in the central parts of which the ends of the arms 2o are located. In this case, the bending deformations of the central parts of the walls of the element 6 arising from pressure cause bending of the arms 2,

When measuring the force, the ends of element 6 are free and do not hinder the deformations of the central parts of its walls, therefore the length of element 6 can be reduced to the thickness of the ends of the arms 2.

In the proposed miniature of an elastic and tensile force, the magnetic resistance of the walls of the expanding section of the magnetic pipeline 1 is an order of magnitude or more less than the magnetic resistance of the air gap between the ends of the arms 2 (R | ("Rj)" therefore the magnetic flux magnetizing windings 5,

it closes mainly through the steaks of element 6 between the ends of the shoulders 2, and not through the aisle gap, as in the known device. Consequently, ceteris paribus, the magnetic fluxes and sensitivity of the proposed sensor are an order of magnitude and higher than that of the known.

The magnetic flux of the proposed sensor flows through a closed magnesium conductor with little interaction with the electromagnetic fields and the shielding elements of the medium. Therefore, the measurement accuracy of the proposed sensor is an order of magnitude higher than the measurement accuracy of the known.

In addition, during bending, the magnetic resistance of the walls of the element 6 between the ends of the arms 2 does not change, since the components of this resistance on both sides of the neutral line of the element 6 of the magnetic circuit change in the pasHbie side. Therefore, the change in the air gap gap between the ends of the shoulders 2 does not affect the magnitude of the magnetic flux of the magnetizing winding 5, since the magnetic flux

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It is shown along the walls of element 6, and not through the air gap between the ends of the arms 2. Therefore, the proposed sensor has a linear characteristic with symmetrical branches.

Formulas

the invention

Magnetoelastic tensile force sensor according to aut. No. 52761, characterized in that, in order to increase accuracy and sensitivity by eliminating the air gap and ensuring the independence of the characteristic from the sign of the measured force, as well as expanding the functionality by providing pressure measurement, the magnetic conductor is made closed, with one of its parts made in the form of two rectangular elastic plates interconnected on the short sides and arranged perpendicular to the center line of the magnetic circuit, while the dimensions of these plates are larger than 1ayut cross-sectional dimensions of the magnetic circuit.

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Claims (1)

Claim Magnetoelastic tensile force sensor according to ed. St. No. 527611, characterized in that, in order to increase accuracy and sensitivity by eliminating the air gap and ensuring the independence of the characteristic from the sign of the measured force, as well as expanding the functionality by providing pressure measurements, the magnetic pipe is closed, one of its parts made in the form of two rectangular elastic plates connected to each other on short sides and located perpendicular to the midline of the magnet-wire, with the dimensions of these plates exceed p measurements of the cross section of the magnetic circuit. Fig.Z