JPH04346278A - Magnetostriction/electrostriction converting element and converter - Google Patents

Abstract

PURPOSE:To provide a small-sized and simple structure magnetostriction/ electrostriction conversion element which has no limit on a service frequency band and a converter employing the conversion element. CONSTITUTION:There is formed a magnetostriction element 3, which expands and constracts integrally with an electrostriction element 2, on this electrostriction element 2 in order to exhibit combined effect of electrostrictive effect and magnetostrictive effect, thus forming a magnetostriction/ electrostriction converting element 1. An input means is installed in one of the electrostriction element 2 or the magnetostriction element 3 whereas an output means is installed in the other element, thus fabricating a voltage/current converter or a current/voltage converter.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetostrictive-electrostrictive mutual conversion element that can be used in voltage-controllable variable inductances, current transformers, modulators, filters, stress sensors capable of outputting both voltage and current, and the like.

0002

BACKGROUND OF THE INVENTION Conventionally, it has been common to use a wire-wound transformer or an active element to perform voltage-to-current conversion. However, the wire-wound transformer has a limited frequency band due to large high-frequency loss, and the use of the active element not only complicates the circuit but also requires a power source to drive it. An object of the present invention is to provide an epoch-making element that can solve the above conventional problems by integrating a magnetostrictive element and an electrostrictive element.

0004

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a structure that is integrated with an electrostrictive element on an electrostrictive element so as to exhibit a mutual effect of an electrostrictive effect and a magnetostrictive effect. A magnetostrictive element that expands and contracts is formed to obtain a magnetostrictive-electrostrictive mutual conversion element that is a passive element. Further, a voltage-current conversion device is constituted by the magnetostrictive-electrostrictive mutual conversion element, input means for supplying an input signal to the electrostrictive element, and output means for extracting an output signal from the magnetostrictive element. Furthermore, a current-voltage conversion device is constituted by the magnetostrictive-electrostrictive mutual conversion element, input means for supplying an input signal to the magnetostrictive element, and output means for taking out an output signal from the electrostrictive element. The magnetostrictive-electrostrictive mutual conversion element, a first output means for taking out an output signal from the electrostrictive element, and a second output means for taking out an output signal from the magnetostrictive element, the electrostrictive element having: A mechanical-electric conversion device is configured by providing a displacement applying section to which mechanical displacement is applied from the outside.

[0005]

[Operation] In the magnetostrictive-electrostrictive mutual conversion element of the present invention, when strain is generated in the electrostrictive element, the magnetostrictive element expands and contracts integrally with the electrostrictive element, and its magnetic properties change. On the contrary,
When strain is generated in the magnetostrictive element, the electrostrictive element expands and contracts together with the magnetostrictive element, and the electrical characteristics of the electrostrictive element change. That is, as a result of the electrostrictive element and the magnetostrictive element expanding and contracting together, the electrostrictive effect and the magnetostrictive effect mutually influence each other. Therefore, it is possible to give an input to one of the electrostrictive element or the magnetostrictive element and extract an output from the other according to the level of the input, and to generate distortion by applying mechanical displacement to the electrostrictive element, Various applications are possible, such as being able to extract voltage and current signals corresponding to this displacement from each of the electrostrictive element and the magnetostrictive element. Moreover, the structure is extremely simple and compact.

Further, the voltage-current converter and current-voltage converter of the present invention apply an input signal to an electrostrictive element or a magnetostrictive element and extract an output signal from the magnetostrictive element or electrostrictive element, so that There is no frequency band limit, and there is no need for complex input and output circuits such as active elements.

Furthermore, the electromechanical conversion device of the present invention includes:
When external displacement is applied to an electrostrictive element, a voltage output signal whose level changes according to the displacement can be extracted from the electrostrictive element, and a current output signal can be extracted from the magnetostrictive element. It is possible to adhere to a member to be measured, detect the stress generated in the member to be measured, and output the detection signal in both voltage and current.

[0008]

[Embodiment] First, a first embodiment of the magnetostrictive-electrostrictive mutual conversion element according to the present invention will be described. FIG. 1 shows an example of a magnetostrictive-electrostrictive mutual conversion element 1, in which Fe78Si is placed on the upper surface of an electrostrictive element 2 made of a thin plate-like PZT (lead zirconate titanate).
A magnetostrictive element 3 made of an amorphous magnetic film (magnetostrictive constant 15×10 −6 ) is formed by high-frequency sputtering using a target material having a composition of 10B12 (magnetostrictive constant 40×10 −6 ). In this way, the electrostrictive element 2 and the magnetostrictive element 3 are integrally coupled, and therefore, the electrostrictive element 2 and the magnetostrictive element 3 expand and contract integrally in the plane direction 5.

The polarization direction P of the electrostrictive element 2 is set upward or downward. Therefore, when a voltage is applied to this electrostrictive element 2 in its polarization direction P, it expands in that direction, while shrinkage occurs in the plane direction 5 of the electrostrictive element 2, and when a voltage is applied in a direction opposite to the polarization direction P, , while shrinkage occurs in that direction, elongation occurs in the in-plane direction 5 of the electrostrictive element 2. On the other hand, when a magnetic field is applied to the magnetostrictive element 3, the magnetostrictive element 3 extends in the direction of the magnetic flux according to the magnetic flux density. Even if the magnetic flux is reversed, the magnetostrictive element 3 does not contract, but still expands according to the magnetic flux density.

FIG. 2 shows a second structure of the magnetostrictive-electrostrictive mutual conversion element 1.
In this embodiment, an electrostrictive element 2 has a polarization direction P along a longitudinal direction 7, and a magnetostrictive element 3 is formed on the upper surface of the electrostrictive element 2. The electrostrictive element 2 has a large number of polarization unit regions 8 divided in the longitudinal direction 7, and adjacent regions 8 have polarization directions P opposite to each other. Therefore, when a voltage is applied to each region 8 of this electrostrictive element 2 in the polarization direction P, the electrostrictive element 2 extends in the longitudinal direction 7, and when a voltage is applied in the opposite direction to the polarization direction P, the longitudinal direction 7 Shrinks to

In the magnetostrictive-electrostrictive mutual conversion element 1 shown in FIGS. 1 and 2 above, when strain is generated in the electrostrictive element 2,
The magnetostrictive element 3 expands and contracts integrally with the electrostrictive element 2, and its magnetic properties change. On the contrary, when strain is generated in the magnetostrictive element 3, the electrostrictive element 2 expands and contracts integrally with the magnetostrictive element 3, and the electrical characteristics of the electrostrictive element 2 change. In other words,
As a result of the electrostrictive element 2 and the magnetostrictive element 3 expanding and contracting integrally, a mutual effect in which the electrostrictive effect and the magnetostrictive effect mutually influence each other is obtained.

Therefore, for example, as shown in FIG. 3, which shows how the magnetostrictive-electrostrictive mutual conversion element 1 of FIG. 1 is used, the electrostrictive element 2
An electrode film 6 is formed on the lower surface of the magnetostrictive element 3, and lead wires 11 and 12 are connected to the magnetostrictive element 3 and the electrode film 6.
An excitation coil 20 is arranged around the outer periphery of the magnetostrictive-electrostrictive mutual conversion element 1 so as to surround the lead wires 11 and 12.
When the electrostrictive element 2 is expanded or contracted by applying an input voltage to the electrostrictive element 2 through the , the magnetostrictive element 3 also expands or contracts integrally with the electrostrictive element 2, thereby increasing or decreasing the magnetic permeability of the magnetostrictive element 3. As the inductance of the coil 20 changes,
An output corresponding to the input voltage can be extracted from this coil 20. This can be used in a voltage-current converter to be described later.

On the contrary, when the magnetostrictive element 3 is expanded by supplying an input current to the coil 20 in FIG. Since the voltage across the strain element 2 changes, an output corresponding to the input current can be taken out from the lead wires 11 and 12. This can be used in a current-voltage converter to be described later.

Furthermore, for example, by fixing the electrostrictive element 2 to a member that causes mechanical displacement, the electrostrictive element 2
It is also possible to apply a mechanical displacement to and extract a voltage signal and a current signal corresponding to this displacement from each of the electrostrictive element 2 and the magnetostrictive element 3. This can be used in a stress sensor that can output both voltage and current, which will be described later.

Next, the results of actually measuring the magnetostrictive effect as a change in magnetic permeability with respect to applied voltage using the magnetostrictive-electrostrictive mutual conversion element of the present invention will be described. Figure 4 shows the equipment used for the actual measurements. In FIG. 4, the magnetostrictive and electrostrictive mutual conversion element 1 and lead wires 11 and 12 are the same as those shown in FIG. The excitation coil 20 is arranged near both ends of the magnetostrictive-electrostrictive mutual conversion element 1 in the longitudinal direction 7 . The electrostrictive element 2 and the magnetostrictive element 3 of the magnetostrictive-electrostrictive mutual conversion element 1 are made of the same material and manufactured by the same method as explained in FIG. 1, and the electrode film 6 is made of gold. The electrostrictive element 2 has a length of 15 mm, a width of 8 mm, and a thickness of 0.6 mm, and the magnetostrictive element 3 has a length of 9 mm, a width of 8 mm, and a thickness of 1 μm. Further, the electrode film 6 has a length of 9 mm and a width of 8 mm.

A voltage is applied to the electrostrictive element 2 from a DC variable voltage source 13 via lead wires 11 and 12, and an AC current is supplied to the excitation coil 20 from an AC power source 14. Furthermore, an 8-shaped detection coil 15 is formed on the upper surface of the magnetostrictive element 3, and a detector 16 for detecting voltage changes is connected to this detection coil 15.

In the actual measurement, while a voltage in the range of -400V to +400V is applied to the electrostrictive element 2 from the DC variable voltage source 13, a voltage of 10 millielsteds is applied from the AC power supply 14 to the excitation coil 20. (mO
With the strength of e), 1MHz, 2MHz, 5MHz,
A magnetic field with a frequency of 10 MHz was applied to the magnetostrictive element 3. In this state, the voltage change occurring in the detection coil 15 was detected by the detector 16, and the relative magnetic permeability μ was calculated from this detected voltage value. The results are shown in FIG. In addition, the above 10
The amount of magnetostriction in the magnetostrictive element 3 caused by the AC magnetic field of mOe is negligible compared to the amount of expansion and contraction of the magnetostrictive element 3 caused by the electrostriction of the electrostrictive element 2. From Figure 5,
It was confirmed that at any frequency, the relative magnetic permeability μ increases or decreases depending on the magnitude of the applied voltage. Note that the vertical axis on the right side of FIG. 5 indicates a value normalized by setting the inductance to 1 when the relative magnetic permeability μ is 100.

Next, a method of wiring to the electrostrictive element 2 in the magnetostrictive-electrostrictive mutual conversion element 1 will be explained. FIG. 6 shows a wiring method to the electrostrictive element 2 in the magnetostrictive-electrostrictive mutual conversion element 1 of FIG. Also used as
A first lead wire 11 is connected to the upper surface of this magnetostrictive element 3. A gold electrode film 6 is formed on the lower surface of the electrostrictive element 2 by sputtering. A magnetostrictive element may be formed in place of this electrode film 6 and used as an electrode. A second lead wire 12 is connected to the electrode film 6 constituting the other electrode, and input to or output from the electrostrictive element 2 is performed via the lead wires 11 and 12. In this wiring method, both electrodes 3
, 6 and lead wires 11, 12 constitute input means or output means.

For example, when a voltage is input to the electrostrictive element 2 from the lead wires 11 and 12 through the electrodes 3 and 6, the thickness of the electrostrictive element 2 changes depending on the level of the applied voltage, and the thickness changes accordingly. It expands and contracts in the plane direction 5.

FIG. 7 shows a wiring method to the electrostrictive element 2 in the magnetostrictive-electrostrictive mutual conversion element 1 of FIG.
), first and second electrodes 22 and 23 arranged in a comb shape are formed on the upper surface of the electrostrictive element 2. These electrodes 22 and 23, as shown in FIG. 7(b),
They are alternately located at the boundaries of the polarization unit regions 8 of the electrostrictive element 2. The first lead wire 11 is led out from the first electrode 22 in FIG. 7A, and the second lead wire 12 is led out from the second electrode 23, and these lead wires 11, 12 and both electrodes 22, Input to or output from the electrostrictive element 2 is performed via 23 (input means or output means).

For example, when a voltage is input to the electrostrictive element 2 through the lead wires 11, 12 and both electrodes 22, 23, when the first electrode 22 is positive and the second electrode 23 is negative, the voltage shown in FIG. Since a voltage is applied in the polarization direction P of the electrostrictive element 2 in (b), the electrostrictive element 2 extends in the longitudinal direction 7. Conversely, when the first electrode 22 is negative and the second electrode 23 is positive, a voltage is applied in the opposite direction to the polarization direction P of the electrostrictive element 2, so the electrostrictive element 2 contracts in the longitudinal direction 7. .

On the other hand, the wiring method for the magnetostrictive element 3 in the magnetostrictive-electrostrictive mutual conversion element 1 is as follows. Normally, the magnetostrictive element 3 is extremely thin, so it is difficult to utilize magnetostriction in the direction perpendicular to the plane direction 5 (vertical direction in FIG. 1) like the electrostrictive element 2 shown in FIG.
Only the magnetostriction along the plane direction 5 is utilized. This is shown in FIGS. 8 and 9.

In FIG. 8, so as to surround the magnetostrictive element 3,
An excitation coil 20 is arranged around the outer periphery of the magnetostrictive-electrostrictive mutual conversion element 1, and input to or output from the magnetostrictive element 3 is performed via this coil 20 and lead wires 25 and 26 derived from the coil 20. In this wiring method, the coil 20 and the lead wires 25 and 26 constitute input means or output means. For example, when a current is input to the coil 20, a magnetic flux H is generated in the longitudinal direction 7 of the magnetostrictive element 3, and regardless of the reversal of this magnetic flux H, the magnetostrictive element 3 is moved in the longitudinal direction 7 by an amount corresponding to the magnetic flux density. It grows to.

In FIG. 9, a folded conducting wire 29 is formed on the upper surface of the magnetostrictive element 3 via an insulating layer 28, and first and second lead wires 25 and 26 led out from this folded conducting wire 29 are connected to each other via an insulating layer 28. input or output to the magnetostrictive element 3. In this wiring method, the lead wire 11
, 12 and the folded conducting wire 29 constitute input means or output means. For example, when a current is input to the folded conductor 29 via both the lead wires 11 and 12, as shown in FIG.
As shown in FIG. 0, since current flows in opposite directions between the adjacent conducting wires 29, the current flows in the magnetostrictive element 3 in its longitudinal direction 7.
Magnetic fluxes H along opposite directions are generated. As a result, the magnetostrictive element 3 extends in the longitudinal direction 7 by an amount corresponding to the magnetic flux density.

The two wiring methods for the magnetostrictive element 3 shown in FIGS. 8 and 9 can be applied to either of the two wiring methods for the electrostrictive element 2 shown in FIGS. 6 and 7. Figure 11 shows four models that combine these wiring methods.
14 to 14.

FIG. 11 shows a model M1 that combines the electrostrictive element side wiring method of FIG. 6 and the magnetostrictive element side wiring method of FIG. While lead wires 11 and 12 are connected to the formed magnetostrictive element 3 and the electrode film 6 formed on the lower surface, an excitation wire is connected to the outer periphery of the magnetostrictive-electrostrictive mutual conversion element 1 so as to surround the magnetostrictive element 3. A coil 20 is arranged, and this coil 2
Lead wires 25 and 26 are derived from 0. The electrostrictive element 2
side lead wires 11, 12 and magnetostrictive element 3 side lead wire 25
, 26, and output signals from the other, an impedance conversion device is obtained.

FIG. 12 shows a model M2 that combines the wiring method on the electrostrictive element side shown in FIG. 6 and the wiring method on the magnetostrictive element side shown in FIG. While the lead wires 11 and 12 are connected to the formed magnetostrictive element 3 and the electrode film 6 formed on the lower surface, a folded conducting wire 29 is provided to the magnetostrictive element 3, and from this folded conducting wire 29, the lead wires 25, 12 are connected. 26 is derived. After all, if an input signal is supplied from one of the lead wires 11 and 12 on the electrostrictive element 2 side and lead wires 25 and 26 on the magnetostrictive element 3 side, and an output signal is taken out from the other, an impedance conversion device is obtained.

FIG. 13 shows a model M3 that combines the electrostrictive element side wiring method of FIG. 7 and the magnetostrictive element side wiring method of FIG. Lead wires 11,
12, while connecting the magnetostrictive element 3 to the bottom surface of the electrostrictive element 2.
An excitation coil 20 is arranged around the outer periphery of the magnetostrictive-electrostrictive mutual conversion element 1 so as to surround the magnetostrictive element 3, and lead wires 25 and 26 are led out from this coil 20. After all, if an input signal is supplied from one of the lead wires 11 and 12 on the electrostrictive element 2 side and lead wires 25 and 26 on the magnetostrictive element 3 side, and an output signal is taken out from the other, an impedance conversion device is obtained.

FIG. 14 shows a model M4 that combines the electrostrictive element side wiring method of FIG. 7 and the magnetostrictive element side wiring method of FIG. A magnetostrictive element 3 is formed in one half, a folded conducting wire 29 is formed on this magnetostrictive element 3, and comb-shaped electrodes 22, 23 are formed on the electrostrictive element 2. This model M4 corresponds to a structure in which the output side of a SAW filter currently in practical use is configured with an electrostrictive element 2 provided with comb-shaped electrodes 22 and 23. If an input signal is supplied from one of the lead wires 11 and 12 on the electrostrictive element 2 side and the lead wires 25 and 26 on the magnetostrictive element 3 side, and an output signal is taken out from the other, an impedance conversion device is obtained.

In the above models M1 to M4, either conversion from electrostriction to magnetostriction or from magnetostriction to electrostriction is performed, but since the conversion is via mechanical strain, mechanical resonance is used. You can perform the following conversions. Since the magnetostrictive element 3 is extremely thin compared to the electrostrictive element 2, only the mechanical resonance of the electrostrictive element 2 can actually be used.

In other words, in any conversion from electrostriction to magnetostriction or from magnetostriction to electrostriction, the vibration mode of the electrostrictive element 2 at the same period as the period of the AC input signal, that is, the conversion accompanied by the direct vibration mode, There are two types of conversion involving the mechanical resonance mode of the electrostrictive element 2. The former is an impedance conversion operation, and the latter is a complex operation in which input frequency selection is performed in conjunction with impedance conversion. However, even in the direct vibration mode, if the comb-shaped electrodes 25 and 26 are used for the electrostrictive element 2 and the folded conducting wire 29 is used for the magnetostrictive element 3, the SAW that simultaneously performs impedance conversion
You get a filter.

[0032]Moreover, model M1 in FIG. 11 and FIG.
In M2 of No. 2, magnetostrictive elements 3 may be formed on both upper and lower surfaces of the electrostrictive element 2, and input or output may be performed to both magnetostrictive elements 3. In that case, both magnetostrictive elements 3 can also be used as electrodes of the electrostrictive element 2.

[0033] The voltage-current converter or current-voltage converter using the above models M1 to M4 has an input/output direction,
As shown in FIG. 15, it is divided into eight categories A to H according to the vibration mode. The operation of each of classifications A to H will be explained below.

Classification A, B Conversion from electrostriction to magnetostriction, that is, voltage-current conversion is performed using model M1 in FIG. 11 or model M2 in FIG. 12. When an AC input voltage is applied to the electrostrictive element 2 through the lead wires 11 and 12 of the electrostrictive element 2, the electrostrictive element 2 generates electrostriction in the polarization direction by an amount corresponding to the voltage level, and Expands and contracts to 7. Along with this expansion and contraction of the electrostrictive element 2, the magnetostrictive element 3 also expands and contracts in the longitudinal direction 7, and the magnetostrictive element 3
magnetic permeability changes.

On the other hand, whether a direct current is superimposed on the coil 20 of model M1 or the folded conductor 29 of model M2,
Alternatively, a magnetic bias is applied to the magnetostrictive element 3 in advance by applying magnetic flux from a permanent magnet. In this way, the inductance value of the coil 20 or the folded conducting wire 29 changes in accordance with the voltage change due to the change in magnetic permeability of the magnetostrictive element 3 in response to the voltage change in the AC input voltage. Here, since a magnetic bias is applied to the magnetostrictive element 3, the change in magnetic permeability causes a change in magnetic flux within the coil.
Similarly, an electromotive force is generated in the coil 20 or the folded conducting wire 29 in accordance with the above voltage change. A current due to this electromotive force is extracted as a current signal via lead wires 25 and 26. As a result, impedance conversion between voltage input and current output is performed, with the lead wires 11 and 12 of the electrostrictive element 2 serving as voltage input and the lead wires 25 and 26 of the magnetostrictive element 3 serving as current output (classifications A and B).

By the way, the electrostrictive element 2 has a fixed mechanical resonance frequency, and resonance occurs when the resonance frequency in the longitudinal direction 7 matches the frequency of the AC input voltage. Therefore, when this resonant frequency and the input frequency are far apart, only the above-mentioned impedance conversion is performed using the direct vibration mode (class A), but when the resonant frequency and the input frequency are close to each other, the resonant mode It has output selectivity with respect to input frequency, and in addition to its original impedance conversion, it also performs frequency selection operation (
Classification B).

Classifications C and D Conversion from magnetostriction to electrostriction, that is, current-voltage conversion is performed using model M1 in FIG. 11 or model M2 in FIG. When an AC input current is applied to the magnetostrictive element 3 via the lead wires 25 and 26 of the magnetostrictive element 3 and a magnetic field is applied to the magnetostrictive element 3, the magnetostrictive element 3 extends in the magnetic flux direction by an amount corresponding to the magnetic flux density ( positive magnetostriction). This elongation of the magnetostrictive element 3 causes the electrostrictive element 2 to bend as shown in FIG. As the thickness of the electrostrictive element 2 changes due to this bending, the voltage between the electrodes 3 and 6 changes, and this voltage change is extracted from the lead wires 11 and 12. As a result, impedance conversion between current input and voltage output is performed (classifications C and D).

At this time, if the resonance frequency of the electrostrictive element 2 and the input frequency are far apart, only the impedance conversion by the direct vibration mode of the electrostrictive element 2 is performed.
Class C): When the resonant frequency and the input frequency are close to each other, the resonant mode has output selectivity with respect to the input frequency, and in addition to the original impedance conversion, it also performs frequency selection operation. (Category D).

Furthermore, the classifications C and D have the advantage that an output that is a multiplication of the input frequency can be obtained, as will be explained below. That is, as shown in FIG. 17(a), when an AC input current Ia with a constant bias is applied to the coil 20 in FIG. 11 or the folded conductor 29 in FIG.
Since the excitation field appears as an increase or decrease in one direction, the amount of elongation of the magnetostrictive element 3 increases or decreases accordingly, and the electrostrictive element 2 produces a voltage output Va with the same period as the input current, as shown in FIG. 17(b). is obtained.

On the other hand, as shown in FIG. 17(c),
The AC input current Ib without bias is applied to the coil 20.
Alternatively, when applied to the folded conductor 29, the direction of the excitation field is reversed every half cycle, but the magnetostrictive element 3 stretches by an amount corresponding to the magnetic flux density (positive magnetostriction) even when the magnetic field is reversed.
The period of expansion and contraction (vibration period) of the magnetostrictive element 3 and the electrostrictive element 2 is 1/2 of the input current Ib. Therefore, as shown in FIG. 17(d), a voltage output Vb having twice the frequency of the input current Ib is obtained.

Classification E, F Conversion from electrostriction to magnetostriction, that is, voltage-current conversion is performed using model M3 in FIG. 13 or model M4 in FIG. First, a case will be described in which model M3 in FIG. 13 is used. When an AC input voltage is applied to the electrostrictive element 2 from the lead wires 11 and 12 of the electrostrictive element 2 through the comb-shaped electrodes 22 and 23, the electrostrictive element 2 is increased by an amount corresponding to the voltage level.
generates electrostriction in the polarization direction along the longitudinal direction 7, and expands and contracts in the longitudinal direction 7. Due to this expansion and contraction, the electrostrictive element 2 is bent, and the magnetostrictive element 3 is also bent integrally with the electrostrictive element 2, as shown in FIG. As a result, the magnetostrictive element 3 expands and contracts in the longitudinal direction 7, and its magnetic permeability changes. The inductance change due to this change in magnetic permeability is extracted as a current signal from the coil 20 via lead wires 25 and 26. This performs impedance conversion of voltage input and current output (classification E, F)

As described above, the model M4 shown in FIG. 14 corresponds to a structure in which the output side of the SAW filter is composed of an electrostrictive element. Therefore, when an AC input voltage is input to the comb-shaped electrodes 22 and 23 of the electrostrictive element 2, the electrostrictive element 2 expands and contracts in the longitudinal direction 7, and vibrations due to the expansion and contraction are transmitted through the surface layer of the electrostrictive element 2, and the electrostrictive element 2 3 and is taken out from the folded conducting wire 29 of the magnetostrictive element 3 via the lead wires 25 and 26 as an alternating current output current. As a result, an operation is performed in which impedance conversion of voltage input and current output is added to the selection operation of a conventional SAW filter (classifications E and F).

In both of the above models M3 and M4, when the resonance frequency of the electrostrictive element 2 and the input frequency are far apart, only the impedance conversion by the direct vibration mode of the electrostrictive element 2 is performed (classification). E) When the resonant frequency and the input frequency are close to each other, the resonant mode has selectivity of the output with respect to the input frequency, and in addition to the inherent impedance conversion,
It also performs frequency selection operations (class F).

Classification G, H Model M3 in FIG. 13 or model M4 in FIG. 14 is used to perform conversion from magnetostriction to electrostriction, that is, current-voltage conversion. The operation is opposite to that explained for the above classifications E and F, and the AC input current supplied from the lead wires 25 and 26 on the magnetostrictive element 3 side is applied to the lead wires 11 and 26 on the electrostrictive element 2 side.
12 as an AC output voltage.

At this time, when the resonance frequency of the electrostrictive element 2 and the input frequency are far apart, only the impedance conversion by the direct vibration mode of the electrostrictive element 2 is performed.
Class G), when the resonant frequency and the input frequency are close to each other, the resonant mode has output selectivity with respect to the input frequency, and in addition to the original impedance conversion, it also performs frequency selection operation. (Class H).

By the way, the magnetostrictive-electrostrictive mutual conversion element 1 of the present invention can be used in addition to the above-mentioned voltage-current or current-voltage conversion device.
It can also be used in stress sensors that can output both voltage and current. In that case, for example, as shown in FIG. 18, the lower surface of the electrostrictive element 2 is made into a displacement adding part 31, and the electrostrictive element 2 is attached to a member 32 that causes mechanical displacement via this adding part 31, such as by bonding. Fix it by some means. As a result, when a mechanical displacement is applied to the electrostrictive element 2 from the member 32, a voltage signal corresponding to this displacement is taken out from the lead wires 11 and 12 of the electrostrictive element 2, and a current corresponding to the displacement is taken out from the lead wires 11 and 12. Signals are taken out from the lead wires 25, 26 of the magnetostrictive element 3. Note that the member 32
A relief groove 33 is provided in the member 32 so that the magnetostrictive element 3 does not come into contact with the member 32 when the electrostrictive element 2 is fixed.

Furthermore, the magnetostrictive-electrostrictive mutual conversion element 1 of the present invention can also be used in an AM modulator shown in FIG. In FIG. 19, the magnetostrictive-electrostrictive mutual conversion element 1 is represented by an equivalent circuit including a capacitor C1 and a variable inductance L1, and functions as a variable inductance that performs a type of voltage-current conversion operation. A capacitor C2 is connected in parallel to the variable inductance L1 to form a parallel resonant circuit 41, and a transistor 42 and a resistor R1 are connected in series to the parallel resonant circuit 41.

An input signal 46 with a frequency fa is supplied between input terminals 44 and 45 connected to both ends of the capacitor C1, and a carrier wave 4 with a frequency fc is supplied to the base of the transistor 42.
7 is supplied. As shown in FIG. 20, C2・L1
If the resonant frequency fo is set higher (or lower) than the carrier frequency fc, L1 changes according to the level of the input signal 46, and as a result, the resonant frequency fo changes due to C2·L1. Due to this change in fo, the impedance of the resonant circuit 41 with respect to the carrier frequency fc changes. In other words, the farther the resonant frequency fo is from the carrier frequency fc, the more the resonance circuit 4 for the carrier frequency fc
The impedance of 1 becomes smaller. When this impedance change is taken out from the output terminal 48 as a voltage change of the resistor R1, a modulation signal 49 AM-modulated by fa
is obtained.

[0049]

[Effects of the Invention] As explained above, the magnetostrictive-electrostrictive mutual conversion element of the present invention can provide an input to either the electrostrictive element or the magnetostrictive element and extract an output from the other according to the level of the input. However, it has a variety of applications, such as applying mechanical displacement to the electrostrictive element to generate strain, and extracting voltage and current signals corresponding to this displacement from the electrostrictive element and magnetostrictive element, respectively. It is possible. Moreover, it has an extremely simple structure, is highly reliable, and is small in size.

Furthermore, the voltage-current converter and current-voltage converter of the present invention apply an input signal to an electrostrictive element or magnetostrictive element and extract an output signal from the magnetostrictive element or electrostrictive element, so that it can be used as a wire-wound transformer. There are no limits on frequency bands, and there is no need for complex input and output circuits such as active elements.

Furthermore, the electromechanical conversion device of the present invention has the following features:
When a displacement is applied to the electrostrictive element from the outside, a voltage output signal whose level changes according to the displacement can be extracted from the electrostrictive element, and a current output signal can be extracted from the magnetostrictive element. Glue it to the part to be measured,
It is possible to realize a stress sensor that detects the stress generated in the member to be measured and outputs the detection signal as both voltage and current.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing a first embodiment of a magnetostrictive-electrostrictive mutual conversion element according to the present invention.

FIG. 2 is a perspective view showing the second embodiment.

FIG. 3 is a perspective view showing an example of a usage mode of the magnetostrictive-electrostrictive mutual conversion element of the present invention.

FIG. 4 is a schematic configuration diagram showing an apparatus used in a test to confirm the effect of the magnetostrictive-electrostrictive mutual conversion element of the present invention.

FIG. 5 is a diagram showing actual measured values from the same test.

FIG. 6 is a perspective view showing an example of a wiring method on the electrostrictive element side of the magnetostrictive-electrostrictive mutual conversion element of the present invention.

[Fig. 7] (a) is a perspective view showing another example of the same wiring method, (b)
) is an enlarged sectional view showing the main part thereof.

FIG. 8 is a perspective view showing an example of a wiring method on the magnetostrictive element side of the magnetostrictive-electrostrictive mutual conversion element of the present invention.

FIG. 9 is a perspective view showing another example of the same wiring method.

10 is a cross-sectional view showing magnetic flux generated in the magnetostrictive-electrostrictive mutual conversion element of FIG. 9. FIG.

FIG. 11 is a perspective view showing a model M1 in which wiring is provided to the magnetostrictive-electrostrictive mutual conversion element of the present invention.

FIG. 12 is a perspective view showing a model M2 in which wiring is provided to the magnetostrictive-electrostrictive mutual conversion element of the present invention.

FIG. 13 is a perspective view showing a model M3 in which wiring is provided to the magnetostrictive-electrostrictive mutual conversion element of the present invention.

FIG. 14 is a perspective view showing a model M4 in which wiring is provided to the magnetostrictive-electrostrictive mutual conversion element of the present invention.

FIG. 15 is a chart categorizing models M1 to M4 according to usage.

FIG. 16 is a side view showing the operation of the magnetostrictive-electrostrictive mutual conversion element of the present invention.

FIG. 17 is a signal waveform diagram showing the input current to the magnetostrictive element and the output voltage from the electrostrictive element of the magnetostrictive-electrostrictive mutual conversion element of the present invention.

FIG. 18 is a perspective view of a stress sensor showing a first embodiment of the electromechanical transducer of the present invention.

FIG. 19 is a circuit diagram showing an example in which the magnetostrictive-electrostrictive mutual conversion element of the present invention is used in an AM modulator.

20 is a diagram showing a waveform of a resonance mode in the AM modulator of FIG. 19. FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1... Magnetostrictive electrostrictive mutual conversion element, 2... Electrostrictive element, 3... Magnetostrictive element, 5... Planar direction, 6... Electrode, 7... Longitudinal direction, 11, 12
...Lead wire on the electrostrictive element side, 20...Coil, 22, 23...
Comb-shaped electrodes, 25, 26...Lead wires on the magnetostrictive element side, 29
...Folded conductor, 32...Displacement adding section, 3, 6, 11, 1
2, 20, 22, 23, 25, 26, 29...input/output means, P...polarization direction.

Claims (4)

[Claims] 1. A magnetostrictive-electrostrictive mutual conversion element, comprising an electrostrictive element and a magnetostrictive element that expands and contracts integrally with the electrostrictive element so as to exhibit a mutual effect of the electrostrictive effect and the magnetostrictive effect. 2. The magnetostrictive-electrostrictive mutual conversion element of claim 1,
A voltage-current converter comprising an input means for supplying an input signal to the electrostrictive element, and an output means for extracting an output signal from the magnetostrictive element. 3. The magnetostrictive-electrostrictive mutual conversion element of claim 1;
A current-voltage conversion device comprising an input means for supplying an input signal to the magnetostrictive element, and an output means for extracting an output signal from the electrostrictive element. 4. The magnetostrictive-electrostrictive mutual conversion element of claim 1;
The electrostrictive element includes a first output means for taking out an output signal from the electrostrictive element, and a second output means for taking out an output signal from the magnetostrictive element, Mechanical-electrical conversion device having a section.