JPH1084596A - Magnetostriction device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify the structure by decreasing number of coils. SOLUTION: Both ends of a magnetostriction member 1 in opposite directions are retained, an external force is given to at least one end of both the ends or a terminal 42 from which a magnetostriction output is obtained is given thereto. A permanent magnet 2 applies a bias magnetic field Hm in a direction of both ends with respect to the magnetostriction member 1 or applies a bias magnetic field Hm in a direction around a major axis O1 directed in both ends. A coil 3 is coupled with the magnetostriction member 1 in a relation in crossing with the direction of the bias magnetic field Hm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a magnetostrictive device using a magnetostrictive element. The magnetostrictive device according to the present invention can be used for an actuator, a motor, a torque sensor, or the like.

[0002]

2. Description of the Related Art This type of magnetostrictive device applies an axial magnetic field and a circumferential magnetic field to a cylindrical body made of a magnetostrictive material, for example, in a motor or an actuator. Magnetostrictive torsion is generated in a cylindrical body made of a magnetostrictive material by the synthesis of a magnetic field, and the rotor is rotated using the magnetostrictive torsion. An axial magnetic field and a circumferential magnetic field for causing magnetostriction torsion are both generated using a coil as disclosed in, for example, Japanese Patent Application Laid-Open No. Hei 7-23290.

When used as a torque sensor, one of two coils is used as a detection coil in the same structure.

One of the problems of the above-described conventional magnetostrictive device is that it is essential to provide two coils in order to generate a magnetic field in the axial direction and a magnetic field in the circumferential direction, resulting in a complicated structure. It is.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a magnetostrictive device having a reduced number of coils and a simplified structure.

[0006]

To solve the above-mentioned problems, a magnetostrictive device according to the present invention includes at least one magnetostrictive member, a permanent magnet, and a coil. The magnetostrictive member is
Both ends in opposite directions are restricted, and at least one end of the both ends has an end to which an external force is applied or a magnetostrictive displacement is output. The permanent magnet applies, to the magnetostrictive member, a bias magnetic field in a direction of a main axis taken in the direction of the both ends or a bias magnetic field in a direction around the main axis. The coil is coupled to the magnetostrictive member such that a direction of a winding axis intersects a direction of the bias magnetic field.

The operation of the above-described magnetostrictive device will be described separately for a case where it is used as a motor or an actuator and a case where it is used as a torque sensor. First,
When the magnetostrictive member is used as a motor or an actuator, the magnetostrictive member is provided with an end that outputs magnetostrictive displacement at least at one end of both ends that are in opposite directions and is constrained.

When a bias magnetic field is applied to the magnetostrictive member by the permanent magnet in the direction of the main axis taken in the direction of both ends, the coil has a winding axis in the magnetostrictive member.
It is coupled to the magnetostrictive member so as to be in a relationship intersecting with the direction of the bias magnetic field, that is, in a direction around the main axis.

Therefore, when the coil is excited by supplying a periodic current, a unidirectional bias magnetic field generated by the permanent magnet and a circulating magnetic field generated by the coil current are generated in the magnetostrictive member. The combined magnetic field generates a magnetostrictive torsional displacement around the main axis in the magnetostrictive member. The magnetostrictive torsional displacement changes according to the cycle of the current flowing through the coil.

Since the magnetostrictive member is provided with an end for outputting a magnetostrictive torsional displacement at one end taken in the direction of the main shaft, the rotor can be rotated by disposing the rotor at this end. it can.

When a permanent magnet applies a bias magnetic field to the magnetostrictive member in a direction around the main axis, the coil includes:
The winding shaft is coupled to the magnetostrictive member such that the direction of the winding shaft matches the direction of the main shaft. When a periodic current flows through the coil to excite it, a circumferential magnetic field generated by the permanent magnet and an axial magnetic field generated by the coil current are generated in the magnetostrictive member. Due to the combined magnetic field, the magnetostrictive member generates a magnetostrictive torsional displacement around the main axis in accordance with the cycle of the coil current.

Next, when used as an actuator,
An end receiving an external force is provided at one end of the magnetostrictive member in the direction of the main shaft. When the permanent magnet applies a bias magnetic field to the magnetostrictive member in the direction of the main shaft, the coil is coupled to the magnetostrictive member such that the direction of the winding axis coincides with the direction around the main shaft.

When an external force is applied to the end of the magnetostrictive member and a displacement occurs that twists the magnetostrictive member around the main axis, the magnetic permeability of the magnetostrictive member changes. For this reason, the magnetic flux density of the magnetostrictive member changes,
The magnetic flux linked to the coil changes, and a voltage is induced in the coil. From the induced voltage, the applied torque can be detected.

When the permanent magnet applies a bias magnetic field to the magnetostrictive member in a direction around the main axis, the coil is coupled to the magnetostrictive member such that the direction of the winding axis matches the direction of the main axis. . Also in this case, when a torque is applied to the end of the magnetostrictive member and the magnetostrictive member twists around the main axis, the magnetic flux density of the magnetostrictive member changes, and a voltage is induced in the coil. From the induced voltage, the applied external force can be detected.
The arrangement of the magnetostrictive member, the permanent magnet, and the coil may have various modes.

In any case, one of the coils conventionally required two is replaced with a permanent magnet and only one coil is required, so that the structure can be simplified.

Other objects, configurations and effects of the present invention will be described in more detail below with reference to the accompanying drawings.

[0017]

FIG. 1 is an exploded perspective view of a magnetostrictive device according to the present invention, FIG. 2 is a plan view showing the magnetostrictive device shown in FIG. 1 with a part thereof removed, and FIG. It is sectional drawing in the A3-A3 line. The magnetostrictive device shown in the embodiment includes one magnetostrictive member 1, a permanent magnet 2, and a coil 3.

The opposite ends of the magnetostrictive member 1 are constrained, and at least one end of both ends has an end to which an external force is applied or which outputs a magnetostrictive displacement. The illustrated magnetostrictive member 1 is a single cylindrical body, and has a lower yoke 41 and an upper yoke 4 at both ends in the direction of the main axis O1.
2 are provided, and the upper yoke 42 constitutes an end to which an external force is applied or which outputs a magnetostrictive displacement. The lower yoke 41 and the upper yoke 42 are connected to the main shaft O of the magnetostrictive member 1.
1 and abut against both end faces in the direction of 1. Then, it is fastened and fixed by a fastening tool 5, whereby the magnetostrictive member 1
Both ends in opposite directions are restrained by the lower yoke 41 and the upper yoke 42.

Magnetostrictive member 1, permanent magnet 2, and lower yoke 4
The housing 6 is provided outside the housing 1, and the lower yoke 41 is fastened together with the bottom 61 of the housing 6 by the fastening tool 5. Both end surfaces in the axial direction of the magnetostrictive member 1 constitute an uneven surface in which projections 101 and recesses 102 are alternately arranged.
And the lower yoke 41.

The permanent magnet 2 applies a bias magnetic field Hm to the magnetostrictive member 1 in the direction of the main axis O1 taken in the direction of both ends. In the embodiment, the permanent magnet 2 is magnetized so as to generate magnetic poles N and S at both ends in the direction of the main axis O1, and is arranged coaxially inside the magnetostrictive member 1.

The coil 3 is coupled to the magnetostrictive member 1 in such a manner that the direction of the winding axis O2 crosses the direction of the bias magnetic field Hm in the magnetostrictive member 1 substantially at right angles. The magnetostrictive member 1 shown in the embodiment is a single cylindrical body,
Is wound around the cylindrical portion 10 of the magnetostrictive member 1 so as to circulate between the inside and the outside thereof. Therefore, coil 3
The direction of the winding axis O2 coincides with the circumferential direction Hc of the magnetostrictive member 1. The coil 3 is wound inside a concave portion 102 provided on both end surfaces of the magnetostrictive member 1 in the direction of the main axis O1. Thereby, the upper yoke 42 can be brought into contact with the end face of the magnetostrictive member 1 without being affected by the wire diameter of the coil 3.

In the embodiment, the permanent magnet 2 is configured to apply a bias magnetic field Hm in the direction of the main axis O1 to the magnetostrictive member 1, and the coil 3 is configured such that the direction of the winding axis O2 is equal to the bias magnetic field Hm. , That is, in the direction Hc around the main axis O1 of the magnetostrictive member 1,
Coupled to the magnetostrictive member 1.

Therefore, when a periodic current is applied to the coil 3 to excite it, a unidirectional bias magnetic field Hm by the permanent magnet 2 and a circulating magnetic field Hc generated by the coil current are applied to the magnetostrictive member 1. Due to the combined magnetic field, a magnetostrictive torsional displacement occurs around the main axis O1 in the magnetostrictive member 1 in accordance with the cycle of the coil current.

The magnetostrictive member 1 is provided with an upper yoke 42 for outputting a magnetostrictive torsional displacement at one end side in the direction of the main axis O1. Can be rotated.

Next, when used as a torque sensor, the upper yoke 42 provided at one end of the magnetostrictive member 1 in the direction of the main axis O1 receives an external force. In the embodiment, the permanent magnet 2
As a result, a bias magnetic field Hm in the direction of the main axis O1 is applied to the magnetostrictive member 1, and the coil 3 moves in the direction of the winding axis O2.
The magnetostrictive member 1 is coupled to the magnetostrictive member 1 in such a relationship as to coincide with the direction Hc around the main axis O1.

An upper yoke 4 constituting an end of the magnetostrictive member 1
When an external force is applied to 2 and the magnetostrictive member 1 is twisted around the main axis O1, the magnetic permeability of the magnetostrictive member 1 changes. Therefore, the magnetic flux density of the magnetostrictive member 1 changes, the magnetic flux linked to the coil 3 changes, and a voltage is induced in the coil 3. From the induced voltage, the applied torque can be detected.

According to the above embodiment, one of the coils 3 conventionally required is replaced by the permanent magnet 2 and only one coil 3 needs to be provided, so that the structure can be simplified.

The magnetostrictive member 1 can be composed of a Ni-Fe magnetostrictive material, an RFe magnetostrictive material, or the like. In particular, it is desirable to use an RFe-based magnetostrictive material. In this case, a sensor having an extremely large change in magnetic resistance, a large output voltage, stable temperature characteristics, and the like can be obtained. Both ends of the magnetostrictive member 1 in the direction of the main axis O1 are restrained and pressurized. Pressurized magnetostrictive member 1
Is applied with a prestress F1 (see FIG. 3). This prestress F1 increases the resistance change of the magnetostrictive member 1 and improves the efficiency.

FIG. 4 is a plan view showing another embodiment of the magnetostrictive device according to the present invention, and FIG. 5 is a partial sectional view taken along line A5-A5 in FIG. In the drawings, the same components as those in FIGS. 1 to 3 are denoted by the same reference numerals, and description thereof will be omitted. The feature of this embodiment is that the permanent magnet 2 is cylindrical. According to this structure, the weight can be reduced as compared with the case of the embodiment shown in FIGS. The arrangement, the direction of magnetization, and other configurations of the permanent magnet 2 are the same as those of the embodiment shown in FIGS. 1 to 3, and therefore, have the same functions and effects as those of FIGS. 1 to 3.

FIG. 6 is a partial sectional view showing another embodiment of the magnetostrictive device according to the present invention. In the figure, the same components as those in FIG. The feature of this embodiment is that the coil 3 is wound so as to surround both the magnetostrictive member 1 and the permanent magnet 2. Other configurations are
This is the same as the embodiment shown in FIG. 4, and has the same operation and effect as FIG.

FIG. 7 is a plan view showing another embodiment of the magnetostrictive device according to the present invention, and FIG. 8 is a partial sectional view taken along line A8-A8 in FIG. In the drawings, the same components as those in FIGS. 1 to 3 are denoted by the same reference numerals, and description thereof will be omitted. The feature of this embodiment is that the permanent magnet 2 has a cylindrical shape and is arranged coaxially outside the magnetostrictive member 1. Other configurations are the same as those of the above-described embodiment, and have similar effects.

FIG. 9 is a plan view showing another embodiment of the magnetostrictive device according to the present invention, and FIG. 10 is a partial sectional view taken along line A10-A10 in FIG. In the figure, the same components as those of the above-described embodiment are denoted by the same reference numerals, and description thereof will be omitted. In this embodiment, the permanent magnet 2 applies a bias magnetic field Hm to the magnetostrictive member 1 in a direction around the main axis O1. The permanent magnet 2 is formed by cutting out a part of the cylindrical magnetostrictive member 1 and fitting the permanent magnet 2 into that part, and forms a cylindrical body together with the magnetostrictive member 1. The permanent magnet 2 is magnetized so that magnetic poles N and S are generated at both ends located in the circumferential direction of the cylindrical body.

The direction of the winding axis O2 is equal to that of the main axis O1.
Are coupled to the magnetostrictive member 1 so as to coincide with the direction of. As a specific means, the embodiment employs a structure in which a coil 3 wound in a solenoid shape is arranged coaxially outside the magnetostrictive member 1. A yoke 43 is arranged outside the cylindrical body to improve the magnetic efficiency with respect to the magnetic flux generated by the current flowing through the coil 3. Both ends of the yoke 43 are in contact with or close to the lower yoke 41 and the upper yoke 42.

When a periodic current is applied to the coil 3 for excitation, the circumferential magnetic field Hm generated by the permanent magnet 2 is applied to the magnetostrictive member 1.
And an axial directional magnetic field Hc generated by the coil current. The combined magnetic field causes the magnetostrictive member 1 to generate a magnetostrictive torsional displacement around the main axis O1 in accordance with the cycle of the coil current.

Next, when used as a torque sensor, the permanent magnet 2 applies a bias magnetic field Hm to the magnetostrictive member 1 in a direction around the main axis O1. The coil 3 is coupled to the magnetostrictive member 1 such that the direction of the winding axis O2 matches the direction of the main axis O1.

When torque is applied to the magnetostrictive member 1,
When a twist occurs around the axis O1, the magnetic flux density of the magnetostrictive member 1 changes, and a voltage is induced in the coil 3. From the induced voltage, the applied external force can be detected.

FIG. 11 is a plan view showing another embodiment of the magnetostrictive device according to the present invention. In the drawings, the same components as those in FIGS. 9 and 10 are denoted by the same reference numerals, and description thereof will be omitted. In this embodiment, a bias magnetic field Hc in a direction around the main axis O1 is applied to the magnetostrictive members 11 and 12 using two permanent magnets 21 and 22. When the permanent magnets 21 and 22 and the magnetostrictive members 11 and 12 are combined with each other,
It is an arc-shaped piece that constitutes one cylindrical body. The permanent magnets 21 and 22 are arranged at positions facing each other in the cylindrical body. The same applies to the magnetostrictive members 21 and 22. The permanent magnets 21 and 21 are magnetized so that magnetic poles N and S are generated at both ends located in the circumferential direction of the cylindrical body, and are arranged so as to generate a bias magnetic field Hm that rotates in one direction.

The direction of the winding axis O2 of the coil 3 is the same as that of the main axis O1.
(See FIG. 10). In the embodiment, as shown in FIGS. 9 and 10, the coil 3 wound in a solenoid shape is arranged coaxially outside the magnetostrictive member 1.

It is apparent that this embodiment also has the same operation and effect as the embodiment shown in FIGS. 9 and 10.

FIG. 12 is a plan view showing another embodiment of the magnetostrictive device according to the present invention. In the figure, the same components as those in FIG. In the embodiment, a large number of permanent magnets 21 to 28 are used, and the magnetostrictive member 1 is used.
A bias magnetic field Hm surrounding the axis O1 in the same direction is applied to 1 to 18. Permanent magnets 21 to 28 and magnetostrictive member 1
When combined with each other, 1 to 18 are arc-shaped pieces that constitute one cylindrical body. Permanent magnets 21 to 28
The magnet is magnetized so as to generate magnetic poles N and S at both ends located in the circumferential direction of the cylindrical body, and is arranged so as to generate a bias magnetic field Hm orbiting in one direction.

As shown in FIG. 10, the coil 3 is coupled to the magnetostrictive member 1 such that the direction of the winding axis O2 coincides with the direction of the main axis O1. In the embodiment, the coil 3 wound in a solenoid shape is arranged coaxially outside the magnetostrictive member 1.

It is apparent that this embodiment also provides the same functions and effects as those of the embodiment shown in FIGS.

FIG. 13 is a plan view showing another embodiment of the magnetostrictive device according to the present invention, and FIG. 14 is a sectional view taken along line A14-A14 of FIG. In the figure, the same components as those in FIG. In the embodiment, a large number of permanent magnets 21 to 28 are used, and the magnetostrictive members 11 to 18 are used.
With respect to the bias magnetic field Hm circling the main axis O1 in the same direction.
Is applied. Permanent magnets 21 to 28 and magnetostrictive members 11 to 1
Numerals 8 are arc-shaped pieces constituting one cylindrical body when combined with each other. The permanent magnets 21 to 28 are magnetized so that magnetic poles N and S are generated at both ends located in the circumferential direction of the cylindrical body, and are arranged in such a manner that a bias magnetic field Hm circulating in one direction is generated.

As shown in FIG. 10, the coil 3 is connected to the cylindrical body so that the direction of the winding axis O2 coincides with the direction of the main axis O1. However, different from the embodiment shown in FIG. 12, the coil 3 is arranged coaxially inside the cylindrical body constituted by the permanent magnets 21 to 28 and the magnetostrictive members 11 to 18. In order to improve the magnetic efficiency with respect to the magnetic flux generated by the current flowing through the coil 3, a yoke 44 is arranged at the axial center of the cylindrical body. Yoke 43
Are in contact with or close to the lower yoke 41 and the upper yoke 42.

It is apparent that this embodiment also has the same operation and effect as those of the embodiment shown in FIGS.

FIG. 15 is a plan view showing another embodiment of the magnetostrictive device according to the present invention. 13 and FIG.
The same components as those described above are denoted by the same reference numerals, and description thereof will be omitted. The permanent magnets 21 to 24 generate a magnetic field Hm1 rotating clockwise and a magnetic field Hm2 rotating counterclockwise around substantially half the circumference of the cylindrical body formed by the combination of the magnetostrictive members 11 and 12.
Specifically, a set of two permanent magnets 21, 22, and 23,
24 is arranged between the two magnetostrictive members 11 and 12. These are, when combined, arc-shaped pieces that constitute one cylindrical body. A set of permanent magnets 21 and 22;
The set of the permanent magnets 23 and 24 is arranged at positions facing each other in the tubular body. The magnetostrictive members 11 and 12 are arranged between them. In the permanent magnets 21 and 22, S
The pole and the S pole face each other, and the N pole and the N pole of the permanent magnets 23 and 24 face each other. Between the set of permanent magnets 21 and 22 and the set of permanent magnets 23 and 24, the magnetostrictive member 1
Opposite poles face each other via 1 and 12.

According to the above configuration, the magnetic field Hm rotating clockwise
1 and a magnetic field Hm2 that rotates counterclockwise. Because the magnitude of magnetostriction does not depend on the direction of the magnetic field,
In this embodiment, the same operation and effect as those of the embodiment shown in FIGS. 13 and 14 can be obtained.

Although the present invention has been described with reference to the preferred embodiments, it will be apparent to those skilled in the art that various modifications can be made to the present invention based on the basic technical concept and scope.
It is obvious.

[0049]

As described above, according to the present invention, it is possible to provide a magnetostrictive device having a reduced number of coils and a simplified structure.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of a magnetostrictive device according to the present invention.

FIG. 2 is a plan view showing a part of the magnetostrictive device shown in FIG.

FIG. 3 is a sectional view taken on line A3-A3 of FIG. 2;

FIG. 4 is a plan view showing another embodiment of the magnetostrictive device according to the present invention.

FIG. 5 is a partial cross-sectional view taken along line A5-A5 in FIG. 4;

FIG. 6 is a partial sectional view showing still another embodiment of the magnetostrictive device according to the present invention.

FIG. 7 is a plan view showing still another embodiment of the magnetostrictive device according to the present invention.

FIG. 8 is a partial cross-sectional view taken along line A8-A8 in FIG. 7;

FIG. 9 is a plan view showing still another embodiment of the magnetostrictive device according to the present invention.

FIG. 10 is a partial cross-sectional view taken along line A10-A10 in FIG. 9;

FIG. 11 is a plan view showing still another embodiment of the magnetostrictive device according to the present invention.

FIG. 12 is a plan view showing still another embodiment of the magnetostrictive device according to the present invention.

FIG. 13 is a plan view showing still another embodiment of the magnetostrictive device according to the present invention.

FIG. 14 is a sectional view taken along line A14-A14 of FIG.

FIG. 15 is a plan view showing still another embodiment of the magnetostrictive device according to the present invention.

[Explanation of symbols]

 1, 11-18 magnetostrictive member 2, 21-28 permanent magnet 3 coil

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yoshio Yamamoto 1-1-18-14-201 Higashi Oshima, Hitachinaka City, Ibaraki Prefecture

Claims (17)

[Claims] 1. A magnetostrictive device including at least one magnetostrictive member, a permanent magnet, and a coil, wherein the magnetostrictive member has opposite ends restricted in opposite directions,
At least one end of the both ends is provided with an external force, or has an end that outputs a magnetostrictive displacement, and the permanent magnet has a bias magnetic field in the direction of the both ends with respect to the magnetostrictive member, or A bias magnetic field is applied in a direction around a main axis taken in the directions of the both ends, and the coil has a magnetostriction coupled to the magnetostrictive member in a relationship that a direction of a winding axis intersects a direction of the bias magnetic field. apparatus. 2. The magnetostrictive device according to claim 1, wherein the magnetostrictive member is a single cylindrical body, and the coil is formed between an inner side and an outer side of a cylindrical portion of the magnetostrictive member. A magnetostrictive device that is wound so as to go around between. 3. The magnetostrictive device according to claim 2, wherein the permanent magnet is disposed coaxially with the magnetostrictive member, and is magnetized so as to generate magnetic poles at both ends in the direction of the main axis. Magnetostrictive device. 4. The magnetostrictive device according to claim 3, wherein the permanent magnet is disposed inside the magnetostrictive member. 5. The magnetostrictive device according to claim 3, wherein the permanent magnet is disposed outside the magnetostrictive member. 6. The magnetostrictive device according to claim 1, wherein a pressure is applied to the magnetostrictive member from both ends in the direction of the main shaft. 7. The magnetostrictive device according to claim 1, wherein the magnetostrictive member and the permanent magnet are combined with each other to form one cylindrical body, and the coil is the cylindrical body. Magnetostrictive device arranged coaxially with respect to. 8. The magnetostrictive device according to claim 7, wherein the permanent magnet generates a magnetic field surrounding the cylindrical body in the same direction. 9. The magnetostrictive device according to claim 7, wherein the permanent magnet generates a magnetic field that rotates in a same direction and a magnetic field that rotates in a reverse direction around substantially a half circumference of the cylindrical body. 10. The magnetostrictive device according to claim 7, wherein the permanent magnet is magnetized so that magnetic poles are generated at both ends located in a circumferential direction of the cylindrical body. 11. The magnetostrictive device according to claim 7, wherein the coil is disposed inside the tubular body. 12. The magnetostrictive device according to claim 7, wherein the coil is disposed outside the tubular body. 13. The magnetostrictive device according to claim 1, wherein the coil is supplied with a current from the outside, thereby generating an alternating magnetic field, and the magnetostrictive member generates a magnetostrictive twist corresponding to the alternating magnetic field. The resulting magnetostrictive device. 14. The magnetostrictive device according to claim 13, wherein the magnetostrictive device is used as an actuator. 15. The magnetostrictive device according to claim 13, wherein the magnetostrictive device is used as a motor. 16. The magnetostrictive device according to claim 1, wherein the coil outputs a signal responsive to the twist when the magnetostrictive member is twisted around the main shaft. 17. The magnetostrictive device according to claim 16, wherein the magnetostrictive device is used as a torque sensor.