JP2005253123A - Magnetostriction actuator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a magnetostriction actuator capable of enhancing reliability while eliminating oscillation in output displacement and response lag. <P>SOLUTION: The magnetostriction actuator 10 comprises a super-magnetostriction rod 16 provided with a super-magnetostriction member and having one end secured to a fixed yoke 14, a drive coil 18 arranged to surround the outer circumference of the super-magnetostriction rod 16, and a section 24 arranged on the free end side of the super-magnetostriction rod 16 and transmitting axial elongation/contraction of the super-magnetostriction rod 16. The transmitting section 24 is secured to the free end of the super-magnetostriction rod 16. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a magnetostrictive actuator using a magnetostrictive member.

  Conventionally, a magnetostrictive actuator using a magnetostrictive member is widely known as an actuator capable of obtaining a large output displacement with a high response speed.

  For example, a conventionally known magnetostrictive actuator 1 shown in FIG. 11 includes a cylindrical casing 2 in which a magnetic field coil 4 to which an electrical signal from a signal supply unit 3 is input, A drive rod 5 made of a magnetostrictive material and driven in the axial direction by the magnetic field coil 4 and an actuator rod 6 for transmitting the displacement of the drive rod 5 to the outside are accommodated. The actuator rod 6 is urged toward the drive rod 5 by an elastic body 7 contracted between the casing 2 and slides following the displacement of the drive rod 5.

  By the way, in such a conventional magnetostrictive actuator, the response speed of the drive rod 5 made of a giant magnetostrictive material is fast, so that the elastic deformation of the elastic body 7 cannot follow the displacement of the drive rod 5, and the response speed of the actuator rod 6 There is a problem that the output displacement of the actuator rod 6 causes ringing vibration.

  Therefore, in the magnetostrictive actuator 1, an electric signal having a rise time equal to or greater than the natural period of the actuator rod 6 is supplied to the magnetic field coil 4 and the drive rod 5 is controlled so as to suppress the vibration of the output displacement of the actuator rod 6. I have to.

JP 2002-171774 A

  However, the magnetostrictive actuator 1 complicates the control of the drive rod 5 and requires a predetermined rise time, so that there is a limit to the speed of response time of output displacement.

  In addition, when the actuator rod 6 cannot follow the displacement of the drive rod 5, the drive rod 5 and the actuator 6 collide in the axial direction, resulting in fatigue of the drive rod 5 and the actuator rod 6 and a decrease in reliability. There was also a problem of end.

  The present invention has been made to solve such problems, and provides a magnetostrictive actuator that can eliminate vibration of output displacement and response delay, and can improve reliability. Objective.

  As a result of intensive studies, the inventors of the present invention have found a magnetostrictive actuator that can eliminate output displacement vibration and response delay, and can improve reliability.

  That is, the above-described object can be achieved by the following present invention.

  (1) A substantially rod-shaped magnetostrictive rod having a magnetostrictive member, one end of which is fixed to a fixed member, a drive coil disposed so as to surround the outer periphery of the magnetostrictive rod, and a free end of the magnetostrictive rod And a transmission part for transmitting the expansion and contraction in the axial direction of the magnetostrictive rod to the outside, and the transmission part is fixed to a free end of the magnetostrictive rod. Magnetostrictive actuator.

  (2) The magnetostrictive actuator according to (1), wherein the transmission unit is fixed via a connecting member for connecting the transmission unit and a free end of the magnetostrictive rod.

  (3) The magnetostrictive actuator according to (1) or (2), wherein the transmission section is detachable from a free end of the magnetostrictive rod.

  (4) The transmission unit includes a movable yoke made of a magnetic member, and the fixed end of the magnetostrictive rod is fixed to a fixed yoke made of a magnetic member. The magnetostrictive actuator in any one of thru | or (3).

  (5) The movable yoke or the fixed yoke in the transmission portion has a substantially columnar pedestal having substantially the same axial diameter as the magnetostrictive rod, and the pedestal and the magnetostrictive rod end are radially outward. The magnetostrictive actuator according to (4), wherein the magnetostrictive actuator is fixed to an end portion of the magnetostrictive rod by a fastening member for fastening from the side.

  (6) The magnetostrictive actuator according to any one of (1) to (5), further comprising a preload spring for applying a preload in the axial direction of the magnetostrictive rod.

  (7) The magnetostrictive actuator according to any one of (1) to (6), wherein the magnetostrictive member is a giant magnetostrictive member made of a giant magnetostrictive element.

  According to the magnetostrictive actuator of the present invention, it is possible to eliminate output displacement vibration and response delay, and to improve the reliability.

  A magnetostrictive actuator according to the present invention comprises a magnetostrictive member having a substantially rod-like magnetostrictive rod having one end fixed to a fixed member, a drive coil disposed so as to surround the outer periphery of the magnetostrictive rod, and the free magnetostrictive rod. A transmission portion disposed on the end side for transmitting the expansion and contraction in the axial direction of the magnetostrictive rod to the outside, and the transmission portion is fixed to a free end of the magnetostrictive rod. This solves the above-mentioned problems.

  Hereinafter, a magnetostrictive actuator according to an embodiment of the present invention will be described in detail with reference to the drawings.

  As shown in FIGS. 1 to 3, a magnetostrictive actuator 10 according to an embodiment of the present invention includes a fixed yoke 14 made of a magnetic member housed and fixed in a substantially cylindrical casing 12, and the fixed yoke 14. A substantially rod-shaped giant magnetostrictive rod 16 having a giant magnetostrictive member, one end of which is fixed to the actuator, a drive coil 18 disposed so as to surround the outer periphery of the giant magnetostrictive rod 16, and the freedom of the giant magnetostrictive rod 16 And a transmission portion 24 including a movable yoke 20 and a transmission rod 22 disposed on the end side.

  The fixed yoke 14 is formed of a substantially disk-shaped magnetic member, and a substantially columnar pedestal 14 </ b> A having a shaft diameter substantially the same as that of the giant magnetostrictive rod 16 is provided at the center thereof. In addition, a circular groove 14B is formed around the pedestal 14A, and two screw holes 14C are formed from the circular groove 14B toward the radially outer side of the fixed yoke 14. The fixed yoke 14 is arranged so that the pedestal 14A is substantially coaxial with the giant magnetostrictive rod 16, and fixed to the giant magnetostrictive rod 16 by a fastening member 26 for fastening the ends of the pedestal 14A and the giant magnetostrictive rod 16 from the outside in the radial direction. Has been.

  As shown in FIG. 3, the fastening member 26 is partially accommodated in the circular groove 14 </ b> B, and two claw members 28 disposed at substantially opposed positions, and two screwed into the screw holes 14 </ b> C. A screw 30 is used. The fastening member 26 tightens two screws 30 from the radially outer side of the fixed yoke 14 toward the circular groove 14B, and sandwiches the giant magnetostrictive rod 16 from the radially outer side with the two claw members 28. Is fixed to the giant magnetostrictive rod 16. The fixed yoke 14 can be attached to and detached from the giant magnetostrictive rod 16 by adjusting the screw 30 of the fastening member 26.

  The giant magnetostrictive rod 16 is made of a giant magnetostrictive element. Here, the “super magnetostrictive element” means a magnetostrictive element made of a powder sintered alloy or a single crystal alloy containing a rare earth element and / or a specific transition metal as a main component (for example, terbium, dysprosium, iron, etc.). It has the property of causing large displacement (expansion and contraction) when a magnetic field is applied from the outside.

  The drive coil 18 can expand and contract the giant magnetostrictive rod 16 in the axial direction by applying a predetermined magnetic field in the axial direction of the giant magnetostrictive rod 16.

  The transmission unit 24 includes a movable yoke 20 having substantially the same shape as the fixed yoke 14 and a transmission rod 22 disposed on the upper part of the movable yoke 20, and the movable yoke 20 and the transmission rod 22 are connected to the movable yoke 20. It is connected and fixed by a female screw formed on the top and a male screw formed on the lower end of the transmission rod 22.

  The movable yoke 20 is fixed to the free end of the giant magnetostrictive rod 16 by a fastening member 26 and adjusts the screw 30 of the fastening member 26 with respect to the giant magnetostrictive rod 16 in the same manner as the fixed yoke 14 described above. It is removable. A preload spring 32 for applying a preload in the axial direction of the giant magnetostrictive rod 16 is contracted between the movable yoke 20 and the casing 12.

  The upper end of the transmission rod 22 protrudes outside the casing 12 and has a structure capable of transmitting the expansion and contraction in the axial direction of the giant magnetostrictive rod 16 to the outside.

  Next, the operation of the magnetostrictive actuator 10 will be described.

  When a predetermined signal is input to the drive coil 18, an axial magnetic field is applied to the giant magnetostrictive rod 16 in accordance with this signal. The giant magnetostrictive rod 16 to which a magnetic field is applied expands and contracts (displaces) in the axial direction due to the magnetostrictive effect, and the expansion and contraction is transmitted to the outside as an output displacement via the transmission unit 24.

  According to the magnetostrictive actuator 10 according to the embodiment of the present invention, a substantially bar-shaped giant magnetostrictive rod 16 having a giant magnetostrictive member and having one end fixed to a fixed yoke (fixed member) 14 and the outer periphery of the giant magnetostrictive rod 16 are provided. A drive coil 18 disposed so as to surround, and a transmission unit 24 disposed on the free end side of the giant magnetostrictive rod 16 for transmitting the axial expansion and contraction of the giant magnetostrictive rod 16 to the outside. In addition, since the transmission unit 24 is fixed to the free end of the giant magnetostrictive rod 16, it is possible to eliminate vibration of output displacement and response delay, and to improve reliability.

  In particular, the movable yoke 20 of the transmission unit 24 includes a substantially columnar pedestal 20A having substantially the same shaft diameter as the giant magnetostrictive rod 16, and the ends of the pedestal 20A and the giant magnetostrictive rod 16 are arranged from the outside in the radial direction. Since it is fixed to the giant magnetostrictive rod 16 by the fastening member 26 for fastening, it is possible to prevent damage to the connecting portion between the transmission portion 24 and the giant magnetostrictive rod 16 in advance.

  That is, since the giant magnetostrictive rod 16 is deformed in a state where the volume is constant, the giant magnetostrictive rod 16 also expands and contracts in the radial direction along with the extension and contraction in the axial direction. Since it is fixed via a fastening member (connecting member) 26 for connecting the ends, the expansion and contraction in the radial direction of the giant magnetostrictive rod 16 does not directly propagate to the transmission unit 24. Therefore, compared with the case where the transmission part 24 and the giant magnetostrictive rod 16 are fixed, the stress applied to the connecting part of the transmission part 24 and the giant magnetostrictive rod 16 is relaxed while allowing the expansion and contraction of the giant magnetostrictive rod 16 in the radial direction. be able to.

  Further, since the transmission unit 24 is detachable from the giant magnetostrictive rod 16, assembly and maintenance of the magnetostrictive actuator 10 are easy.

  Further, the transmission unit 24 has a movable yoke 20 made of a magnetic member fixed to the free end of the giant magnetostrictive rod 16, and the fixed end of the giant magnetostrictive rod 16 is made of a fixed yoke 14 made of a magnetic member. Therefore, the magnetic circuit is configured by the giant magnetostrictive rod 16, the drive coil 18, the fixed yoke 14, and the movable yoke 20, and the magnetic field of the drive coil 18 can be efficiently guided in the axial direction of the giant magnetostrictive rod 16. The output displacement of the magnetostrictive actuator 10 can be increased.

  Further, since the preload spring 32 for applying a preload in the axial direction of the giant magnetostrictive rod 16 is provided, the output displacement of the magnetostrictive actuator 10 can be further increased.

  The magnetostrictive actuator according to the present invention is not limited to the shape and structure of the magnetostrictive actuator 10 according to the present embodiment.

  Therefore, for example, as shown in FIG. 4, if a plurality of (two in this example) screws 30 are provided for one claw member 28, the giant magnetostrictive rod 16 and the fixed yoke 14 are further strengthened. Can be fixed. The movable yoke 20 can have the same structure as the fixed yoke 14, and the same applies to other embodiments described below.

  Further, like the fixed yoke 34 shown in FIG. 5, one of the claw members 28 is integrated with the fixed yoke 34, or both the claw members 28 are fixed to the fixed yoke 34 like the fixed yoke 36 shown in FIG. If the claw portion 36A is formed integrally with 36 and the giant magnetostrictive rod 16 is sandwiched and fixed by the elastic force of the claw portion 36A, the structure can be simplified as compared with the magnetostrictive actuator 10 according to the above embodiment. At the same time, the number of parts can be reduced.

  Further, as shown in FIG. 7, a substantially ring-shaped recess is formed on the outer peripheral surface of the giant magnetostrictive rod 38, and a projection that can be fitted into the recess of the giant magnetostrictive rod 38 on the claw 40 </ b> A of the fixed yoke 40. As compared with the magnetostrictive actuator 10 according to the above embodiment, the structure is simple, the number of parts can be reduced, and the super-magnetostrictive rod 38 can be more firmly fixed in the axial direction.

  Furthermore, as shown in FIG. 8, even if the giant magnetostrictive rod 42 and the fixed yoke 44 are fixed by the male screw formed at the lower end of the giant magnetostrictive rod 42 and the female screw formed at the upper portion of the fixed yoke 44. It is possible to simplify the structure and reduce the number of parts.

  Further, as shown in FIG. 9, a structure in which the fixed yoke 34 is fixed to the supermagnetic rod 16 by a plurality of claw members 48 integrated with the fixed yoke 46 and a connecting member 52 constituted by a ring-shaped member 50. It is good.

  In the above embodiment, the transmission unit 24 is configured by the movable yoke 20 and the transmission rod 22. However, the present invention is not limited to this. For example, the movable yoke 20 and the transmission rod 22 are integrated and transmitted. Further, like the magnetostrictive actuator 60 shown in FIG. 10, the transmission unit may be configured by only the transmission rod 62, and the giant magnetostrictive rod 16 and the transmission rod 62 may be directly fixed.

  When importance is attached to downsizing of the magnetostrictive actuator 10, the fixed yoke 14 and the movable yoke 20 need not be provided. For example, the fixed end of the giant magnetostrictive rod 16 is fixed to the casing 12, and the giant magnetostrictive rod is fixed. The 16 free ends may be fixed to the transmission rod 22.

  Further, when the output displacement of the magnetostrictive actuator 10 is sufficiently obtained, a magnetostrictive rod made of a magnetostrictive member may be applied instead of the super magnetostrictive rod 16, and the preload spring 32 may not be provided.

  That is, a magnetostrictive actuator according to the present invention includes a magnetostrictive member, a substantially rod-shaped magnetostrictive rod having one end fixed to a fixed member, a drive coil disposed so as to surround an outer periphery of the magnetostrictive rod, and the magnetostrictive rod And a transmission portion for transmitting the expansion and contraction in the axial direction of the magnetostrictive rod to the outside, and the transmission portion is fixed to the free end of the magnetostrictive rod. It only has to be.

Schematic side sectional view of a magnetostrictive actuator according to an embodiment of the present invention Schematic sectional view taken along line II-II in FIG. 1 is a partially exploded perspective view around the fixed yoke in FIG. Schematic sectional view showing an example in which two screws are arranged on the claw member in FIG. Schematic side sectional view showing an example in which one of the claw members in FIG. 1 is integrated with a fixed yoke Schematic side sectional view showing an example in which both of the claw members in FIG. 1 are fixed with a fixed yoke Schematic side sectional view showing an example in which a fixed yoke is fixed using a recess formed on the outer peripheral surface of a giant magnetostrictive rod Schematic side sectional view showing an example in which the giant magnetostrictive rod and the fixed yoke are fixed by the male screw of the giant magnetostrictive rod and the female screw of the fixed yoke The partially exploded perspective view which shows the other example of the connection member which concerns on this invention Schematic side sectional view showing an example of direct connection of transmission rod and giant magnetostrictive rod Schematic side sectional view of a conventional magnetostrictive actuator

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 10, 60 ... Magnetostrictive actuator 2, 12 ... Casing 3 ... Signal processing part 4 ... Magnetic field coil 5 ... Drive rod 6 ... Actuator rod 7 ... Elastic body 14, 34, 36, 40, 44, 46, 64 ... Fixed yoke 16, 38, 42 ... Giant magnetostrictive rod 18 ... Driving coil 20 ... Movable yoke 22, 62 ... Transmission rod 24 ... Transmission part 26 ... Fastening member 28, 48 ... Claw member 30 ... Screw 32 ... Preload screw 50 ... Ring-shaped member 52. Connecting member

Claims (7)

  A substantially rod-shaped magnetostrictive rod having a magnetostrictive member, one end of which is fixed to the fixing member, a drive coil disposed so as to surround the outer periphery of the magnetostrictive rod, and a free end of the magnetostrictive rod, A magnetostrictive actuator, wherein the magnetostrictive rod is fixed to a free end of the magnetostrictive rod. In claim 1,
The magnetostrictive actuator, wherein the transmission part is fixed via a connecting member for connecting the transmission part and a free end of the magnetostrictive rod. In claim 1 or 2,
The magnetostrictive actuator, wherein the transmission unit is detachable from a free end of the magnetostrictive rod. In any one of Claims 1 thru | or 3,
The transmission unit includes a movable yoke made of a magnetic member, and a fixed end of the magnetostrictive rod is fixed to a fixed yoke made of a magnetic member. In claim 4,
The movable yoke or the fixed yoke in the transmission portion has a substantially columnar pedestal having substantially the same shaft diameter as the magnetostrictive rod, and fastens the pedestal and the magnetostrictive rod end from the outside in the radial direction. A magnetostrictive actuator, wherein the magnetostrictive rod is fixed to the end of the magnetostrictive rod by a fastening member. In any one of Claims 1 thru | or 5,
A magnetostrictive actuator comprising a preload spring for applying a preload in the axial direction of the magnetostrictive rod. In any one of Claims 1 thru | or 6.
The magnetostrictive member is made of a giant magnetostrictive member made of a giant magnetostrictive element.

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