JP7295433B2 - Magnetostriction measuring device and magnetostriction measuring method - Google Patents

Description

The present invention relates to a magnetostriction measuring device and a magnetostriction measuring method.

In general, magnetic materials exhibit magnetostriction, which is a phenomenon in which the dimensions of a material change as the magnetization of the material changes. The magnetostriction phenomenon of an electromagnetic steel sheet, when the electromagnetic steel sheet is used for the iron core of a transformer that is AC-excited, for example, causes vibration of the iron core, which causes noise emitted from the transformer. For this reason, reduction in magnetostriction is required for the electrical steel sheet. In grain-oriented electrical steel sheets used in transformers, the magnetostriction in the longitudinal direction (rolling direction) of the steel sheet is often taken up and evaluated in consideration of the structure of the iron core. For this reason, it is required to accurately evaluate the magnetostrictive properties of steel sheets in the longitudinal direction, and technical developments have been made to improve the accuracy and applied to measuring devices.

An example of a magnetostriction measuring device is shown in FIG. In this magnetostriction measuring apparatus, one electromagnetic steel sheet sample having a width of 100 mm and a length of 500 mm is arranged so as to pass through an exciting coil, and an alternating magnetic field is applied by the exciting coil. Also, the yoke is used to form a closed magnetic circuit. In FIG. 1, the sample is mechanically fixed by a clamp on the left side of the excitation coil, and the vibration of the sample due to the magnetostrictive phenomenon (magnetostrictive vibration) appears on the right side of the clamp (the side where the excitation coil is arranged). . Further, in this magnetostriction measuring apparatus, magnetostriction vibration measurement is performed using a laser vibrometer capable of differential measurement. Specifically, a small block (reflector) that reflects the laser light is adhered to the position (measurement point) where the sample vibrates due to magnetostriction, and one of the laser beams of the laser vibrometer is irradiated there. In addition, a small block (reflector) that reflects the laser light is installed at a fixed point (reference point) that is not affected by vibration due to magnetostriction, and the other laser light from the laser vibrometer is irradiated there. . Then, the vibration of the sample is measured based on the reflected light from each small block. An example of such technology is disclosed in US Pat.

JP-A-4-5524 JP-A-9-203605

The problem in magnetostriction measurement is how to accurately measure submicron vibrations. Regarding this problem, Patent Document 2 describes one of the problems related to measurement accuracy. The invention according to Patent Document 2 performs magnetostriction measurement by sandwiching a sample between two flat substrates. Patent Document 2 mentions that the friction between the flat substrate and the sample suppresses the change in the length of the sample due to magnetostriction. means to However, Patent Document 2 only mentions that the mass of the flat substrate is determined in relation to the coefficient of friction of the flat substrate in order to deal with this problem, and does not describe a method for positively removing the influence of friction. Not presented.

The present invention has been made in view of the above circumstances, and provides a magnetostriction measuring apparatus and a magnetostriction measuring method capable of reducing measurement errors due to friction between a material whose magnetostrictive characteristics are to be measured and a substrate with which this material is in contact. intended to

In order to achieve the above object, the magnetostriction measuring apparatus of the present invention measures the displacement of the other end of a plate-shaped material placed in an alternating magnetic field and fixed at one end to measure the magnetostrictive characteristics of the plate-shaped material. A magnetostriction measuring device for measuring
A substrate with which the bottom surface of the plate-shaped material is in contact,
The substrate is characterized in that it can vibrate in a magnetostrictive measurement direction.

In the present invention, the substrate with which the plate-like material is in contact can be vibrated. It is possible to remove the effect of friction based on the measured magnetostrictive properties.

Further, in the configuration of the present invention, a control device for controlling vibration of the substrate is provided,
The control device may control the vibration of the substrate so that the direction of vibration of the substrate and the direction of displacement of the plate-shaped material are aligned in the measurement direction.

In this way, by aligning the vibration direction of the substrate and the displacement direction of the plate-shaped material, it becomes easy to organize the relationship between the displacement of the plate-shaped material and the frictional force applied to the plate-shaped material, and the influence of friction is eliminated. easier to do.

Further, in the configuration of the present invention, the control device may control the vibration of the substrate so that the vibration speed of the substrate is faster than the displacement speed of the plate-shaped material in the measurement direction. good.

According to such a configuration, it is possible to stably apply a frictional force in a direction that promotes deformation due to magnetostriction while the substrate is vibrated. Therefore, the data measured with the substrate stationary and frictional force acting in the direction that hinders the deformation of the sample due to magnetostriction and the data measured with the substrate vibrating and the frictional force acting in the direction that promotes deformation of the sample due to magnetostriction It is possible to remove the effect of friction by measuring the data measured by and averaging them.

Further, the magnetostriction measuring method of the present invention is a magnetostriction measuring method for measuring the magnetostrictive characteristics of a plate-like material placed in an alternating magnetic field and having one end fixed by measuring the displacement of the other end of the plate-like material. and
a stationary state measurement step of contacting the bottom surface of the plate-shaped material with a substrate and measuring the magnetostriction characteristics while the substrate is stationary;
a vibration state measuring step of contacting the bottom surface of the plate-shaped material with the substrate and measuring the magnetostrictive characteristics while vibrating the substrate in the magnetostrictive characteristic measurement direction;
A step of averaging the magnetostrictive properties measured in the static state measuring step and the magnetostrictive properties measured in the vibrational state measuring step is included.

According to the present invention, it is possible to measure the magnetostrictive properties in both the state where the substrate is stationary and the state where the substrate is vibrated, and remove the effect of friction based on the magnetostrictive properties measured in both states. becomes.

In the configuration of the present invention, in the vibration state measuring step, the substrate may be vibrated so that the direction of vibration of the substrate and the direction of displacement of the plate-shaped material are aligned in the measurement direction. .

In this way, by aligning the vibration direction of the substrate and the displacement direction of the plate-shaped material, it becomes easy to organize the relationship between the displacement of the plate-shaped material and the frictional force applied to the plate-shaped material, and the influence of friction is eliminated. easier to do.

Further, in the configuration of the present invention, in the vibration state measuring step, the substrate may be vibrated such that the vibration speed of the substrate is faster than the displacement speed of the plate-like material in the measurement direction. good.

According to such a configuration, it is possible to stably apply a frictional force in a direction that promotes deformation due to magnetostriction while the substrate is vibrated. Therefore, the data measured with the substrate stationary and frictional force acting in the direction that hinders the deformation of the sample due to magnetostriction and the data measured with the substrate vibrating and the frictional force acting in the direction that promotes deformation of the sample due to magnetostriction It is possible to remove the effect of friction by measuring the data measured by and averaging them.

According to the present invention, it is possible to reduce measurement errors due to friction between a material whose magnetostrictive characteristics are to be measured and a substrate with which this material is in contact.

It is a figure which shows an example of the conventional magnetostriction measuring device. 1 is a schematic diagram showing a magnetostriction measuring device according to an embodiment of the present invention; FIG. FIG. 4 is a diagram showing a waveform representing vibration of a sample and a waveform representing vibration of a substrate; 4 is a flowchart for explaining a stationary state measurement process; 4 is a flowchart for explaining a vibration state measuring process; It is the schematic which shows the 1st modification of a magnetostriction measuring apparatus equally. It is the schematic which shows the 2nd modification of a magnetostriction measuring apparatus equally.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
The inventors of the present invention considered the effects of friction in order to reduce measurement errors in magnetostriction measurements. First, let's talk about this.

In magnetostriction measurements, magnetostriction manifests itself as a vibration of the sample. Specifically, in the magnetostriction measurement, the expansion and contraction of the sample are repeated periodically. When the sample is placed on the substrate, friction occurs between the sample and the substrate. This friction inhibits the elongation of the sample and makes it smaller than the original elongation amount. Moreover, this friction inhibits the shrinkage of the sample when it shrinks, making the amount of shrinkage smaller than it should be. Therefore, when there is friction, the amplitude of vibration (displacement) due to magnetostriction becomes smaller than the original value. It can be said that the deformation of the sample due to magnetostriction is partly absorbed by the elastic deformation caused by the frictional force.

In general, dynamic friction is called Coulomb friction, and the frictional force generated between an object and the surface on which this object is placed is proportional to the product of the friction coefficient and the normal force due to the mass of the object, and the sliding speed is said to be irrelevant. In conventional schemes, such as that shown in FIG. 1, the substrate with which the sample contacts is always stationary. Therefore, the frictional force always works to inhibit the deformation (displacement) of the sample due to magnetostriction. Therefore, in the present invention, the substrate is moved in the direction in which the magnetostriction is measured to intentionally change the direction of the frictional force. Specifically, during the period in which the sample is stretched by magnetostriction, the substrate moves away from the clamp, that is, in the direction in which the frictional force exerts an elongation strain on the sample, thereby promoting deformation (displacement) of the sample by magnetostriction. On the other hand, during the period in which the sample shrinks due to magnetostriction, the substrate moves toward the clamp, that is, in the direction in which the frictional force exerts shrinkage strain on the sample, thereby promoting the deformation of the sample due to magnetostriction. Such a state is obtained by vibrating the substrate in the direction of magnetostriction measurement.

Deformation of the sample due to frictional force is considered as a kind of elastic deformation. Therefore, the coefficient corresponding to the elastic modulus is a constant value. Also, as mentioned above, the frictional force is not affected by the sliding velocity. From these facts, the amount of displacement generated by hindering deformation due to magnetostriction when the substrate is not moved, and the amount of displacement generated due to the acceleration of deformation due to magnetostriction when the substrate is vibrated The increments have the same absolute value. Therefore, the deformation (displacement) of the sample due to magnetostriction is measured and recorded by matching the phases of the deformation (displacement) of the sample due to magnetostriction when the substrate is fixed and when it is vibrating. However, by averaging these values, the promotion and hindrance of deformation due to friction are offset, and magnetostrictive characteristics free from the influence of friction can be obtained.

FIG. 2 shows a magnetostriction measuring device 10 according to this embodiment. The magnetostriction measuring device 10 includes a substrate 18, a pedestal 20, a yoke 22, a substrate support member 24, a clamp 26, an exciter 28, a reflector 30, an exciting coil 32, a laser vibrometer 40, A vibration sensor 42 , an A/D converter 44 , a computer (controller) 46 , an arbitrary waveform generator 48 , a power amplifier 50 and a drive power supply 52 are provided. Yoke 22 , substrate support member 24 , clamp 26 and vibrator 28 are fixed to base 20 . The magnetostrictive property of a sample (material) 8 to be measured is measured by this magnetostrictive measuring device 10 .

In the following description, the horizontal direction in FIG. 2 is defined as the X direction, the vertical direction in FIG. 1). The X direction is the measurement direction. That is, the magnetostriction measuring device 10 measures the magnetostriction characteristics of the sample 8 in the X direction.
2 is a schematic diagram of the magnetostriction measuring apparatus 10, and includes a sample 8, a substrate 18, a pedestal 20, a yoke 22, a substrate supporting member 24, a clamp 26, a vibrator 28, a reflector 30, an exciting coil 32, 4 is a diagram combining a diagram showing the positional relationship between a laser vibrometer 40 and a vibration sensor 42 and a block diagram. FIG. Therefore, the actual positional relationship of the A/D converter 44, computer 46, arbitrary waveform generator, power amplifier 50 and drive power supply 52 does not match the X, Y and Z directions shown in FIG. Moreover, the basic configuration of the magnetostriction measuring device 10 may be appropriately the same as that of the conventional magnetostriction measuring device shown in FIG.

Further, in the present embodiment, the sample 8 is a plate-like plate having a width (length in the Y direction) of 100 mm and a length (length in the X direction) of 500 mm (the length in the Z direction is the length in the X direction (shorter than the length in the direction). That is, the longitudinal direction (rolling direction) of the sample 8 coincides with the measurement direction. In addition, the size of the sample 8 may not be as described above, and the sample 8 may not necessarily have a plate shape.

The substrate 18 is a plate made of a non-conductive material (non-magnetic material). Specifically, for example, a bakelite plate or a glass epoxy plate can be used as the substrate. The substrate 18 has a rectangular plate shape, and the sample 8 is placed on the substrate 18 . That is, the bottom surface of the sample 8 is in contact with the top surface of the substrate 18 . Further, the substrate 18 is supported from below by the substrate support member 24 and the yoke 22 . That is, the substrate 18 rests on the substrate support member 24 and the yoke 22 . Specifically, of the two opposing sides (first side and second side) of the bottom surface of the substrate 18, the bottom surface of the substrate 18 and the substrate support member 24 are in contact with each other near the first side. The bottom surface of the substrate 18 and the yoke 22 are in contact with each other in the vicinity. Here, the first side and the second side are parallel to the Y direction.

The yoke 22 has the same shape as the yoke shown in FIG. 1, and has a substantially rectangular frame shape. In other words, the yoke 22 has four straight portions, and these straight portions are integrated so as to form a square shape when viewed in the Z direction. Moreover, the sample 8 is constructed so as to span between two opposing straight portions of the yoke 22 . A closed magnetic circuit is formed by the yoke 22 and the sample 8 .

The substrate support member 24 has a cross-sectional shape on the XZ plane that tapers upward. Further, the substrate support member 24 has a cross-sectional shape on the YZ plane that tapers upward. In other words, the substrate supporting member 24 is formed so that the contact area with the bottom surface of the substrate 18 is small (so that the substrate 18 is in contact with the substrate 18 substantially at a point). A plurality of substrate support members 24 are arranged side by side in the Y direction.

Further, the substrate 18 is not fixed to the substrate supporting member 24 and the yoke 22, and is slidable (linearly movable) on the substrate supporting member 24 and the yoke 22. As shown in FIG. In other words, the substrate 18 can vibrate relative to the pedestal 20 . Specifically, the substrate 18 can vibrate (linearly move) in the X direction. Moreover, the sample 8 is not fixed to the substrate 18 and is slidable (linearly movable) on the substrate 18 . In other words, the sample 8 can vibrate relative to the substrate 18 . Specifically, the sample 8 can vibrate (linearly move) in the X direction.

In the magnetostriction measuring device 10 of this embodiment, the contact area between the substrate 18 and the substrate supporting member 24 is reduced to reduce the friction between the substrate 18 and the substrate supporting member 24. For example, the contact portion between the substrate 18 and the substrate support member 24 and the contact portion between the substrate 18 and the yoke 22 may be provided with rollers (rotating bodies) to reduce the friction.

The clamps 26 are designed to sandwich and fix the sample 8 . That is, the clamp 26 serves as a fixing member that fixes the sample 8 to the pedestal 20 . The sample 8 is arranged on the substrate 18, and is clamped so that one end 8a in the X direction (the left end in FIG. 2, hereinafter referred to as the first end) is sandwiched between the clamps 26 and fixed. It has become. Here, the first end portion 8a rests on the yoke 22 and is in contact with the yoke 22 outside the clamp 26 (end side (left side in FIG. 2)). The other end 8b of the sample 8 in the X direction (the right end in FIG. 2, hereinafter referred to as the second end) is not fixed by the clamp 26 or the like and is a free end. That is, when the sample 8 expands and contracts due to magnetostriction, frictional force from the substrate 18, etc., the portion fixed to the clamp 26 is used as a fixing point, and the portion closer to the second end 8b than the fixing point is the clamp 26. and relative to the pedestal 20. The second end portion 8b side of the fixing point is a portion of the sample 8 to be measured, and the expansion and contraction of the portion is measured.
The first end 8a of the sample 8 is placed directly on the yoke 22, while the second end 8b is placed on the yoke 22 with the substrate 18 interposed therebetween. However, the first end portion 8a may rest on the yoke 22 via a non-conductive member (non-magnetic member) such as the substrate 18 or a small piece of the same material and thickness as the substrate 18. . Alternatively, the second end portion 8b may be placed directly on the yoke 22 without the substrate 18 interposed therebetween.

The exciting coil 32 is wound around the outside of the substrate 18 so that the substrate 18 is positioned inside. Also, the excitation coil 32 is wound in a tubular shape with its axis extending in the X direction. The magnetic flux passing through the excitation coil 32 is directed in the X direction. The sample 8 placed on the substrate 18 passes through the exciting coil 32 in the X direction.
It should be noted that the excitation coil 32 only needs to be able to induce magnetostriction in the sample 8 . Specifically, for example, when the sample 8 is placed on the substrate 18 , it is preferable that at least part of the sample 8 (and the substrate 18 ) be positioned inside the exciting coil 32 . Further, the exciting coil 32 may be wound around a cylindrical member (for example, a member made of a non-conductive material (non-magnetic material) such as bakelite) inside which the substrate 18 is arranged. good.

The vibration exciter 28 is capable of vibrating the substrate 18 relative to the pedestal 20 . The vibrator 28 has a vibrating movable portion. This movable portion is coupled to the substrate, so that the substrate 18 can be vibrated in the X direction. The vibration exciter 28 may be, for example, a piezoelectric element or a mechanical vibrator made of giant magnetostrictive material to generate vibration. Further, the vibration exciter 28 may be, for example, one that causes vibration by a force such as a motor or air, as long as it can apply appropriate vibration to the substrate 18 . Also, the vibrator 28 may be one that can generate vibration by combining a plurality of elements such as piezo elements, giant magnetostrictive materials, motors, and air.

The reflector 30 can reflect the laser light from the laser vibrometer 40 . For the reflector 30, for example, a bakelite block (for example, a block of several millimeters cube) to which a reflective tape that reflects the laser beam is attached, or an L-shaped member having a reflective portion that reflects the laser beam can be used. However, the structure is not particularly limited as long as it can reflect laser light.

In the magnetostriction measuring device 10 of the present embodiment, two reflectors 30a and 30b are prepared as the reflectors 30 for reflecting the laser beam from the laser vibrometer 40. FIG. One reflector 30a is fixed to the sample 8 and is displaced according to the expansion and contraction of the sample 8. FIG. Another reflector 30b is independent of the sample 8 and is not displaced even when the sample 8 expands and contracts. In other words, the reflector 30b is directly or indirectly fixed to the pedestal 20 so that even if the sample 8 or substrate 18 is displaced (vibrated) in the X direction, the reflector 30b is not displaced in the X direction. It has become. Reflector 30b may be fixed to yoke 22 or clamp 26, for example.

The laser vibrometer 40 is a laser Doppler vibrometer, which irradiates the reflectors 30a and 30b with laser light and detects reflected light (reflected laser light) from each of the reflectors 30a and 30b. ing. That is, reflected light from the reflectors 30a and 30b is input to the laser vibrometer 40 as a differential signal. Based on this differential signal, the laser vibrometer 40 generates a vibration waveform (magnetostrictive waveform) representing the vibration of the sample 8 and outputs it as an output signal. In other words, the laser vibrometer 40 can measure the vibration of the sample 8 . Here, the vibration of the sample 8 measured by the laser vibrometer 40 (the magnetostrictive waveform generated by the laser vibrometer 40) in a state where an alternating magnetic field is applied by the exciting coil 32 represents the magnetostrictive characteristics of the sample 8. is. That is, the laser vibrometer 40 can measure the magnetostrictive properties of the sample 8 .

The vibration sensor 42 is a sensor that detects vibration of the substrate 18 and is a laser Doppler vibrometer. Further, the substrate 18 is provided with a reflector (substrate-side reflector) that reflects the laser light from the vibration sensor 42 . The vibration sensor 42 irradiates the substrate-side reflector and the reflector 30b with laser light and detects reflected light (reflected laser light) from these reflectors. That is, reflected light from the substrate-side reflector and the reflector 30b is input to the vibration sensor 42 as a differential signal. Based on this differential signal, the vibration sensor 42 generates a vibration waveform (substrate vibration waveform) representing the vibration of the substrate 18 and outputs it as an output signal. In other words, the vibration sensor 42 can measure vibration of the substrate 18 .

The A/D converter 44 is a two-channel analog-to-digital converter. The output signal of the laser vibrometer 40 is input to one channel of the A/D converter 44, and the output signal of the vibration sensor 42 is input to the other channel. Further, the A/D converter 44 can convert the output signal (magnetostrictive waveform) of the laser vibrometer 40 and the output signal (substrate vibration waveform) of the vibration sensor 42 into digital signals and output them. ing.

The reflector 30b used by the laser vibrometer 40 to grasp the position of the reference point and the reflector 30b used by the vibration sensor 42 to grasp the position of the reference point are separate bodies. good too. Also, the laser vibrometer 40 and the vibration sensor 42 do not have to measure vibration based on differential signals. In other words, the laser vibrometer 40 or the vibration sensor 42 receives only the reflected light from the reflector 30a or the reflected light from the substrate-side reflector (single input), and based on this input reflected light, Vibration may be measured by That is, in the present embodiment, the reflector 30b is used to calculate the position of the reference point that serves as the reference for measuring the displacement of the sample 8 or the substrate 18. Under the premise that it is fixed, the position of the reference point using the reflector 30b may not be calculated.
Also, the laser vibrometer 40 and the vibration sensor 42 may not measure using the Doppler effect of laser light as long as they can measure the vibration of the sample 8 or the substrate 18 . For example, a laser displacement gauge may be used as a non-contact measuring device that similarly uses laser light. Alternatively, a measuring device using a piezoelectric element, an acceleration sensor, or a strain gauge, or a measuring device using a change in electric capacity depending on the distance between electrodes may be used.

Computer 46 is connected to A/D converter 44 and arbitrary waveform generator 48 . The arbitrary waveform generator 48 is also connected to a power amplifier 50 that supplies power to the excitation coil 32 and a driving power supply 52 that drives the vibrator 28 . The arbitrary waveform generator 48 is a two-channel waveform generator, and can output a signal (waveform) for exciting the excitation coil 32 from one channel, and the power amplifier 50 excites according to this signal. Electric power is supplied to the coil 32 to excite the excitation coil 32 . In addition, the arbitrary waveform generator 48 can output a signal (waveform) for vibrating the vibration exciter 28 from the other channel, and the drive power supply 52 drives the vibration exciter 28 according to this signal. It's becoming That is, the output waveform from one channel of arbitrary waveform generator 48 is applied to excitation coil 32 via power amplifier 50, and the output waveform from the other channel is applied to vibrator 28 via drive power supply 52. It is designed to be given.

The output signal of the laser vibrometer 40 converted by the A/D converter 44 and the output signal of the vibration sensor 42 are input to the computer 46 . The computer 46 controls the signals to be applied to the exciting coil 32 and the vibration exciter 28 based on the output signal of the laser vibrometer 40 and the output signal of the vibration sensor 42 . Specifically, computer 46 sets arbitrary waveform generator 48 so that sample 8 is excited under predetermined conditions. In other words, the computer sets the arbitrary waveform generator 48 so that the sample 8 oscillates under predetermined conditions due to magnetostriction. The computer 46 also sets the arbitrary waveform generator 48 so that the vibration exciter 28 vibrates under predetermined conditions. Then, the arbitrary waveform generator 48 excites the excitation coil 32 via the power amplifier 50 and vibrates the vibrator 28 via the drive power source 52 based on the setting by the computer 46 .

The magnetostriction measuring apparatus 10 generates an alternating magnetic field with an exciting coil 32, magnetostrictively deforms the sample 8 placed in the alternating magnetic field, and measures the magnetostrictive characteristics of the sample 8. FIG. Specifically, the magnetostrictive characteristics are measured in two states, that is, the state in which the substrate 18 on which the sample 8 is placed is stationary and the state in which it is vibrated, and the average of the magnetostrictive characteristics measured in both states is obtained. Acquire magnetostrictive characteristics with reduced (removed) measurement errors due to Specifically, as shown in FIG. 3, the magnetostriction waveform (static magnetostriction waveform a) measured in the state where the substrate 18 is stationary (the substrate vibration waveform becomes the stationary state waveform d), and the substrate 18 is Obtaining a magnetostriction waveform (oscillating magnetostriction waveform b) measured in a vibrating state (state in which the substrate vibration waveform becomes a vibration state waveform e), and obtaining an average of the static magnetostriction waveform a and the vibration magnetostriction waveform b. Obtain an average magnetostrictive waveform c.
Note that the vibration of the sample 8 is basically repeated at half the period (twice the frequency) of the AC magnetic field generated by the exciting coil 32 .

The flow of magnetostriction measurement of the sample 8 by the magnetostriction measuring device 10 will be described below with reference to FIGS.

First, the measurement while the substrate 18 is stopped without vibrating (static state measurement step) will be described with reference to FIG.
First, the computer 46 sets the arbitrary waveform generator 48 to excite the excitation coil 32 so that the sample 8 is excited under predetermined conditions (step S1). Specifically, the computer 46 causes the exciting coil 32 to generate an alternating magnetic field so that the sample 8 periodically expands and contracts (oscillates) in the X direction due to magnetostriction.

Next, the laser vibrometer 40 measures the vibration of the sample 8 vibrating under this alternating magnetic field (step S2). This measurement result is the measurement result of the magnetostrictive characteristics when the substrate 18 is stopped. In the magnetostriction measuring apparatus 10 of the present embodiment, the waveform representing the vibration of the sample 8 when the substrate 18 is stationary (static magnetostriction waveform a (see FIG. 3)) is used to measure the magnetostriction characteristics when the substrate 18 is stationary. Although obtained as a result, the measurement result does not have to be a waveform, as long as it represents the magnetostrictive properties of the sample 8 in that state.

Next, the measurement (vibration state measurement step) while the substrate 18 is vibrated will be described with reference to FIG.
First, the computer 46 sets the arbitrary waveform generator 48 to excite the excitation coil 32 so that the sample 8 is excited under predetermined conditions (step S11). Specifically, the computer 46 causes the exciting coil 32 to generate an alternating magnetic field so that the sample 8 periodically expands and contracts (oscillates) in the X direction due to magnetostriction.

Next, the computer 46 sets the arbitrary waveform generator 48 to vibrate the vibration exciter 28 so that the substrate 18 vibrates under predetermined conditions (step S12). Specifically, the computer 46 vibrates the vibration exciter 28 so that the substrate 18 periodically vibrates in the X direction.

Next, the laser vibrometer 40 detects vibration of the sample 8, and the vibration sensor 42 detects vibration of the substrate 18 (step S13). Then, the magnetostrictive waveform representing the vibration of the sample 8 detected by the laser vibrometer 40 and the substrate vibration waveform representing the vibration of the substrate 18 detected by the vibration sensor 42 are transmitted via the A/D converter 44 to the computer 46 . sent to

Next, the computer 46 determines whether or not the magnetostriction measurement conditions are satisfied while the substrate 18 is vibrating, based on the magnetostrictive waveform and the substrate vibration waveform (step S14). Here, the measurement conditions are satisfied when the vibration direction of the substrate 18 and the vibration direction of the sample 8 match in the X direction and the vibration speed of the substrate 18 exceeds the vibration speed of the sample 8 ( If not, it is determined that the measurement conditions are not satisfied (NO in step S14), and the process proceeds to step S15.

In the process of step S15, the computer 46 modifies the waveform applied to the vibration exciter 28 and modifies the vibration mode of the substrate 18 so as to satisfy the measurement conditions. That is, the computer 46 controls the vibration direction of the substrate 18 and the vibration direction of the sample 8 in the X direction so that the vibration speed of the substrate 18 exceeds the vibration speed of the sample 8. change the shape, amplitude, frequency, etc. In other words, the computer 46 provides the vibration exciter 28 with the upper and lower peak positions of the substrate vibration waveform (timing at which the vibration direction switches) to coincide with the upper and lower peak positions of the magnetostrictive waveform (timing at which the vibration direction switches). Correct the waveform. In other words, the computer 46 provides the vibrator 28 with the vibration magnetostrictive waveform b and the vibration state waveform e synchronized so that the vibration magnetostriction waveform b and the vibration state waveform e are in phase. Modify the waveform (see Figure 3). For this purpose, the computer 46 is equipped with software that executes a feedback loop that modifies the waveform applied to the vibration exciter 28 based on the magnetostrictive waveform and the substrate vibration waveform.
In adjusting the relationship between the magnetostrictive waveform and the substrate vibration waveform, the computer 46 does not correct the signal (vibration mode of the substrate 18) given to the vibration exciter 28, but the signal given to the exciting coil 32 (sample 8). ) may be modified, and both the signal applied to the vibration exciter 28 and the signal applied to the excitation coil 32 may be modified.

When the process of step S15 ends, the process returns to step S13. That is, the processes of steps S13 to S15 are repeated until the measurement conditions are satisfied. Then, when the measurement conditions are satisfied (YES in step S14), the process proceeds to step S16.

In the process of step S16, the laser vibrometer 40 measures the vibration of the sample 8 vibrating under the AC magnetic field and in a state satisfying the measurement conditions. The result of this measurement is the result of measurement of the magnetostrictive characteristics while the substrate 18 is vibrating. In the magnetostriction measuring apparatus 10 of the present embodiment, the waveform representing the vibration of the sample 8 when the substrate 18 vibrates (vibration magnetostriction waveform b (see FIG. 3)) is used to measure the magnetostriction characteristics when the substrate 18 vibrates. Although obtained as a result, the measurement result does not have to be a waveform, as long as it represents the magnetostrictive properties of the sample 8 in that state.

As described above, the laser vibrometer 40, the vibration sensor 42, the A/D converter 44, the computer 46, and the arbitrary waveform generator 48 constitute a feedback system. The vibration of the sample 8 and the vibration of the substrate 18 based on the output) are input to the laser vibrometer 40 and the vibration sensor 42, and the vibration of the sample 8 and the vibration of the substrate 18 are in a desired state that satisfies the measurement conditions. As such, computer 46 controls the output from arbitrary waveform generator 48 . In the vibration state measuring process, even after proceeding to the process of step S16, the processes of steps S3 to S15 may be continued to adjust the vibration of the substrate 18 as appropriate.

Either the stationary state measurement process or the vibration state measurement process may be performed first. Further, the above-described steps in the stationary state measurement process and the vibration state measurement process may not be performed in the order as described above, and the order may be changed as appropriate.

When the magnetostrictive characteristics are measured in each of the static state measurement process and the vibration state measurement process, a process (average processing) is performed. Specifically, as shown in FIG. 3, the amplitude of the static magnetostrictive waveform a and the amplitude of the oscillating magnetostrictive waveform b are averaged to obtain an average magnetostrictive waveform c from which the effect of friction has been removed.
It is preferable to excite the exciting coil 32 (sample 8) under the same conditions in the stationary state measurement process and the vibration state measurement process. In other words, in the static state measurement process and the vibration state measurement process, as shown in FIG. 3, the sample 8 is vibrated so that the frequencies of the static magnetostrictive waveform a and the oscillating magnetostrictive waveform b match. In other words, the sample 8 is vibrated so that the upper and lower peak positions of the stationary magnetostrictive waveform a (timing at which the vibration direction switches) coincide with the upper and lower peak positions of the oscillating magnetostrictive waveform b (timing at which the vibration direction switches). In other words, the sample 8 is vibrated so that the stationary magnetostrictive waveform a and the oscillating magnetostrictive waveform b are synchronized and the stationary magnetostrictive waveform a and the oscillating magnetostrictive waveform b are in phase.
Note that the averaging process may be performed by averaging the measurement results of the static state measurement process and the measurement results of the vibration state measurement process to obtain magnetostrictive characteristics with reduced measurement errors due to friction. Further, the averaging process may be performed by the computer 46, by the laser vibrometer 40, or by another computer capable of handling the output signal of the laser vibrometer 40. FIG.

As described above, the magnetostriction measuring apparatus 10 of the present embodiment measures the displacement of the other end (second end 8b) of the sample 8 placed in an alternating magnetic field and fixed at one end (first end 8a). A magnetostrictive measuring apparatus for measuring the magnetostrictive properties of a sample 8 by measuring, provided with a substrate 18 with which the bottom surface of the sample 8 is in contact, and the substrate 18 can vibrate in the magnetostrictive property measurement direction. According to such a configuration, the magnetostrictive characteristics are measured in a plurality of states, such as a state in which the substrate 18 is stationary and a state in which the substrate is vibrated. can be removed.

The magnetostriction measuring apparatus 10 also includes a computer 46 that controls the vibration of the substrate 18. The computer 46 controls the vibration of the substrate 18 so that the direction of vibration of the substrate 18 and the direction of displacement of the sample 8 are aligned in the measurement direction. Control. Therefore, the vibration direction of the substrate 18 and the displacement direction of the sample 8 are aligned, it becomes easy to organize the relationship between the displacement of the sample 8 and the frictional force applied to the sample 8, and it becomes easy to remove the influence of the friction. .

The computer 46 also controls the vibration of the substrate 18 so that the vibration speed of the substrate 18 is faster than the displacement speed of the sample 8 in the measurement direction. Therefore, in a state where the substrate 18 is vibrated, it is possible to stably apply a frictional force in a direction that promotes deformation of the sample due to magnetostriction. Therefore, the data measured with the substrate 18 stationary and the frictional force acting in the direction that hinders the deformation of the sample due to magnetostriction, and the data measured with the substrate 18 vibrated and the frictional force acting in the direction that the deformation of the sample due to magnetostriction is promoted. It is possible to measure the data measured under working conditions and average them to remove the effects of friction.

As shown in FIG. 3, the displacement of the sample 8 due to magnetostriction monotonically increases from the minimum displacement point to the maximum displacement point, and monotonously decreases from the maximum displacement point to the minimum displacement point. It is not necessarily the case. That is, depending on the magnetostrictive properties of the sample 8, the direction of displacement may be switched between the point at which the displacement is minimum and the point at which the displacement is maximum. Even in such a case, the computer 46 preferably controls so that the vibration direction of the substrate 18 is also switched each time the displacement direction of the sample 8 is switched.

When the substrate 18 is moved, the speed of the substrate 18 must be set to exceed the displacement speed due to magnetostriction in order to promote the displacement of the sample 8 due to magnetostriction. In particular, when high-precision magnetostriction measurement is required over the entire period of expansion and contraction of the sample 8, it is preferable to ensure that the acceleration of the displacement due to magnetostriction is always generated over the entire period. ), the velocity of the substrate is preferably set to exceed the displacement velocity due to magnetostriction. However, the speed of the substrate does not always have to exceed the displacement speed due to magnetostriction in one cycle. That is, even if there are some points in one cycle where the speed of the substrate is lower than the displacement speed due to magnetostriction, by averaging the measurement results when the substrate is stationary and when the substrate is vibrating, Measurement errors can be reduced. Further, data measured in a state where the speed of the substrate 18 is lower than the displacement speed due to magnetostriction may be excluded and averaged.

Moreover, the measurement of the magnetostrictive property in the state where the substrate 18 is vibrated may be divided into several times. For example, when the direction of vibration of the substrate 18 and the direction of displacement of the sample 8 due to magnetostriction are in the direction away from the clamp 26 (right direction in FIG. 2), the direction of vibration of the substrate 18 and the direction of displacement of the sample 8 due to magnetostriction are , the magnetostrictive characteristics in the direction approaching the clamp 26 (leftward direction in FIG. 2), and the magnetostrictive characteristics may be measured separately, and these may be synthesized to obtain the measurement result in the substrate vibrating state. By dividing the measurement in this way, there is no need to match the switching timing of the displacement direction of the sample 8 due to magnetostriction and the switching timing of the vibration direction of the substrate 18, etc., and the speed of the substrate 18 exceeds the displacement speed due to magnetostriction. Easy to keep in good condition.

In addition, when measuring the magnetostrictive properties while the substrate 18 is vibrating, the vibration of the substrate 18 and the displacement of the sample 8 may not be synchronized (they may not be of the same frequency). For example, while applying a constant alternating magnetic field to the sample 8, the substrate 18 is randomly vibrated (vibrated without synchronizing with the displacement of the sample 8) so that the vibration direction of the substrate 18 and the displacement direction of the sample 8 are the same. Then, the data at the point where the vibration speed of the substrate 18 exceeds the displacement speed of the sample 8 is extracted, and the data in the state where the frictional force acts in the direction in which the deformation of the sample due to magnetostriction is promoted, such as the vibration magnetostrictive waveform b, is obtained. It may be acquired.

In Coulomb friction, the sliding speed does not affect the magnitude of the frictional force, so if the vibration speed of the substrate 18 exceeds the displacement speed of the sample 8 at the moment magnetostriction is measured, the vibration waveform of the substrate 18 is arbitrary. be able to. For example, in FIG. 3, the substrate vibration waveform (vibration state waveform e) is a triangular wave. good too.

Modifications of the magnetostriction measuring device 10 of the present embodiment are shown in FIGS. 6 and 7. FIG. Here, in the modified examples shown in FIGS. 6 and 7 , the magnetostriction measuring device 10 includes a driving device 60 . The drive device 60 is a device that vibrates the substrate 18 . The driving device 60 includes, for example, a control device 46 that controls vibration of the substrate 18 and a vibration exciter 28 that vibrates the substrate 18 . Here, the controller 46 may control the vibration of the substrate 18 by referring to the actual vibration of the sample 8 and the substrate 18 by means of the feedback loop as described above. The vibration may be controlled without reference to the vibration.

In the first modification shown in FIG. 6, both ends in the X direction of the substrate 18 are supported from below by substrate support members 24 , 24 . Further, the substrate supporting member 24 has a columnar shape with an axis extending in the Y direction, and the outer peripheral surface is in contact with the substrate 18 . That is, the substrate support member 24 has a curved surface that contacts the substrate 18 . A driving device 60 is also connected to the substrate 18 . A driving device 60 vibrates the substrate 18 in the X direction.
The substrate support member 24 may rotate in the circumferential direction around the axis as the substrate 18 moves in the X direction.

In a second variant shown in FIG. 7, the drive 60 is connected to the belt. Further, the driving device 60 can rotate the belt. In a second variant, the samples 8 are placed on the belt. That is, the belt (upper surface of the belt) functions as the substrate 18 . The rotation of the belt causes the substrate 18 to move in the X direction. Specifically, rotation of the belt in a given direction moves the substrate 18 away from the clamps 26 in the X direction, and rotation of the belt in the opposite direction moves the substrate 18 toward the clamps 26 in the X direction. It's like That is, the vibration of the substrate 18 is realized by switching the rotation direction of the belt.
It should be noted that the substrate 18, which is separate from the belt, may be arranged on the belt.

In addition, the embodiment described above is merely an example for carrying out the present invention. Therefore, the present invention is not limited to the above-described embodiments, and modifications such as replacement or deletion of each component can be made without departing from the scope of the present invention.

8 Sample (plate material)
10 magnetostriction measuring device 18 substrate 46 computer (control device)

Claims (6)

A magnetostriction measuring device for measuring the magnetostrictive properties of a plate-like material by measuring the displacement of the other end of the plate-like material placed in an alternating magnetic field and having one end fixed,
A substrate with which the bottom surface of the plate-shaped material is in contact,
A magnetostriction measuring apparatus, wherein the substrate is capable of vibrating in a magnetostrictive measurement direction. A control device for controlling vibration of the substrate,
2. The magnetostriction measurement according to claim 1, wherein the control device controls the vibration of the substrate so that the direction of vibration of the substrate and the direction of displacement of the plate-shaped material are aligned in the measurement direction. Device. 3. The magnetostriction according to claim 2, wherein the control device controls the vibration of the substrate so that the vibration speed of the substrate is faster than the displacement speed of the plate material in the measurement direction. measuring device. A magnetostriction measuring method for measuring the magnetostrictive properties of a plate-shaped material by measuring the displacement of the other end of the plate-shaped material placed in an alternating magnetic field and fixed at one end, comprising:
a stationary state measurement step of contacting the bottom surface of the plate-shaped material with a substrate and measuring the magnetostriction characteristics while the substrate is stationary;
a vibration state measuring step of contacting the bottom surface of the plate-shaped material with the substrate and measuring the magnetostrictive characteristics while vibrating the substrate in the magnetostrictive characteristic measurement direction;
A method for measuring magnetostriction, comprising the step of averaging the magnetostriction characteristics measured in the static state measurement step and the magnetostriction characteristics measured in the vibration state measurement step. 5. The magnetostriction measurement according to claim 4, wherein in the vibration state measuring step, the substrate is vibrated so that the vibration direction of the substrate and the displacement direction of the plate-shaped material are aligned in the measurement direction. Method. 6. The magnetostriction according to claim 5, wherein in the vibration state measuring step, the substrate is vibrated such that the vibration speed of the substrate is faster than the displacement speed of the plate-shaped material in the measurement direction. Measuring method.

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