JP3302777B2 - Moving magnet type actuator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to control equipment, electronic equipment,
The present invention relates to a movable magnet type actuator for converting electric energy into reciprocating kinetic energy or the like by electromagnetic action in a machine tool or the like.

[0002]

2. Description of the Related Art A movable magnet type reciprocating apparatus having a structure shown in FIG. 6 is conventionally known. In the conventional example of FIG. 6, reference numeral 10 denotes a magnet movable body composed of a rod-shaped permanent magnet magnetized in the axial direction, and has magnetic poles on both end surfaces.
The coils 11A and 11B are respectively wound around the outer peripheral side of the end portion of the magnet movable body 10 in a ring shape, so that the same polarity is generated in adjacent portions. The coil 11
A and 11B are usually mounted on a guide cylinder 12 for guiding the magnet movable body 10 movably in the axial direction. The magnetic flux from each end face of the magnet movable body 10 is linked with the coils 11A and 11B, respectively.

FIG. 7 shows a reference example which has been previously proposed by the present applicant. In the reference example shown in FIG. 7, the magnet movable body 15 has
A, 16B and a bar-shaped soft magnetic body 17 fixed between the permanent magnets 16A, 16B are integrally fixed. The triple coils 18A, 18B, 18C are arranged on the outer peripheral side of the magnet movable body 15. Is wound around the magnet movable body 1
5, the left end of the permanent magnet 16A, the permanent magnet 16A,
The permanent magnet 16B is disposed so as to interlink with the magnetic flux from the same pole opposing end of the permanent magnet 16B and the magnetic pole at the right end of the permanent magnet 16B.
These coils 18A, 18B, 18C are
Connections are made so that currents flow in different directions with the magnetic poles of A and 16B as boundaries (the boundary between magnetic poles does not necessarily have to be at the magnetic pole intermediate position if it is between magnetic poles). Note that the coils 18A, 18B, and 18C are usually
Guide cylinder 1 for movably guiding shaft 5 in the axial direction
9 is attached. The positional relationship between the coils 18A, 18B, 18C and the magnet movable body 15 is such that, at most of the movable positions of the magnet movable body 15, the currents flowing through the coils are opposite to each other with the boundary between the permanent magnet magnetic poles. Set as follows.

In the above-described conventional example and the reference example, the thrust generated in the magnet movable bodies 10 and 15 basically conforms to the thrust given based on Fleming's left hand rule (Fleming's left hand). Is applied to the coil, but here, since the coil is fixed, a thrust as a reaction force of the force acting on the coil is generated in the magnet movable body.) Therefore, what contributes to the thrust is the vertical component (the component orthogonal to the axial direction of the permanent magnet) of the magnetic flux of the permanent magnet that the movable magnet has.

[0005] Then, in the case of one permanent magnet or two permanent magnets of the same pole opposition, analysis was made on the vertical component of the magnetic flux.

FIG. 8 shows the result of a magnetic field analysis of the vertical component of the surface magnetic flux density along the longitudinal side surface of a single permanent magnet.
However, the permanent magnet is a rare earth permanent magnet, with a diameter of 7 mm,
A position having a length of 14 mm and a distance of 0.8 to 1.0 mm from the surface of the permanent magnet was measured.

FIG. 9 shows a case where two permanent magnets are arranged at the same pole opposition, and a soft magnetic material having a length of 2 mm is arranged between the two permanent magnets, the surface magnetic flux along the longitudinal side surfaces of the two permanent magnets. The result of the magnetic field analysis of the vertical component of the density is shown. However, each permanent magnet is a rare earth permanent magnet, 7 mm in diameter and 7 mm in length.
Then, a position 0.8 to 1.0 mm away from the surface of the permanent magnet was measured.

FIG. 10 shows two permanent magnets of the same polarity facing each other, a soft magnetic material having a length of 2 mm disposed between the two permanent magnets, and a soft magnetic material having a length of 2 mm also disposed on the outer end faces of the two permanent magnets. FIG. 9 shows the results of a magnetic field analysis of the vertical component of the surface magnetic flux density along the longitudinal side surfaces of two permanent magnets when the bodies are arranged. However, each permanent magnet is a rare earth permanent magnet, 7 mm in diameter and 7 mm in length, and 0.8 to 1.0 mm from the surface of the permanent magnet.
The distance was measured.

[0009]

As described above, the thrust generated on the magnet movable body basically conforms to the thrust given based on Fleming's left hand rule.
Although it is desired that the perpendicular component of the magnetic flux of the permanent magnet interlinking with the coil be large (a component orthogonal to the axial direction of the permanent magnet), the perpendicular component of the surface magnetic flux density is, as shown in FIG. That is, it was found that the vertical component was smaller than that in the case where the two permanent magnets of FIGS. For this reason, in the configuration of the conventional example shown in FIG. 6, there is a limit in improving the thrust. For example, the magnet movable body 10 has a diameter of 7 mm and a length of 1 mm.
It is composed of a 4 mm rare earth permanent magnet, and has two coils 11A,
11B so that the same polarity is generated in adjacent portions of both coils 1B.
When a total of 5 W of power is input to 1A and 11B (117
The thrust F1 generated when a current of mA was applied) was 165 (gf) as shown in the table below.

On the other hand, in the reference example of FIG. 7, a magnet movable body 15 in which a soft magnetic body 17 is arranged between two permanent magnets 16A and 16B of the same polarity is used, and the vertical component of the magnetic flux density is shown in FIG.
As shown in FIG. 8, the magnetic flux emitted from the magnetic poles of the permanent magnets 16A and 16B facing each other is a single permanent magnet (see FIG. 8).
It is possible to improve the thrust. For example, in the reference example of FIG.
6, two rare earth permanent magnets having a length of 7 mm and a length of 7 mm are used (the performance of the rare earth permanent magnets is assumed to be the same as that of the conventional example), and a soft magnetic material having a length of 2 mm is arranged between the two. Coil 18A, 18 made to have the same power consumption as the example
When a total of 5 W of power is input to B and 18C (117 m
The thrust F2 generated when the current of A was applied was 215 (gf) as shown in the following table. However, in the case of the reference example of FIG. 7, when focusing on the magnetic flux emitted from the outer end surfaces of the permanent magnets 16A and 16B, the vertical component of the magnetic flux tends to be slightly smaller.

[0011] Table With yoke Without yoke Conventional example 190 gf 165 gf Reference example 250 gf 215 gf The present invention 275 gf 235 gf

In the conventional example shown in FIG. 6 and the reference example shown in FIG. 7, if the cylindrical yoke 20 made of a soft magnetic material is arranged outside the coil as indicated by a virtual line, the vertical component of the magnetic flux density of the permanent magnet increases. Therefore, the thrust increases.

The present invention has been made in view of the above points, and
Provided is a movable magnet type actuator that improves thrust and efficiency by using a magnet movable body in which pieces of permanent magnets are arranged in the same polarity and facing each other, and by effectively utilizing magnetic flux generated by each magnetic pole of the permanent magnet. The purpose is to:

[0014]

In order to achieve the above object, a movable magnet type actuator according to the present invention is provided with an intermediate magnetic body between at least two permanent magnets having the same polarity and opposed to each other. An end magnetic body is provided on the outer end surface of the permanent magnet to form a magnet movable body, and the magnet movable body is movably provided inside at least three coils , and is located at an intermediate position among the at least three coils. Thing at the end position
Wider than that of the permanent magnet from the opposite end of the same pole
The arrangement is to interlink with the magnetic flux of
The arrangement is to link with the magnetic flux from the end poles of the permanent magnet.
In addition, the coils are connected such that currents flow in different directions from the magnetic poles of the permanent magnets as boundaries.

A magnetic circuit for increasing a magnetic flux component in a direction perpendicular to the magnetization direction of the permanent magnet may be provided by providing a magnetic yoke on the outer periphery of the coil.

Further, the permanent magnet, the intermediate magnetic body and the end magnetic body may be integrated with a non-magnetic holder to constitute the movable magnet body.

Further, there is a case where an output extracting pin is provided on the magnet movable body.

[0018]

The basic structure of the movable magnet type actuator according to the present invention will be described with reference to the schematic diagram of FIG. In FIG. 5, the magnet movable body 3 is composed of two columnar permanent magnets 5 arranged in the same pole opposition.
A, 5B, a columnar intermediate soft magnetic body 6A fixed between these permanent magnets 5A, 5B, and permanent magnets 5A, 5B.
As shown in FIG. 10, not only the permanent magnets 5A, 5B but also the permanent magnets 5A, 5B are integrated with the permanent magnets 5A, 5B.
B has a structure in which a vertical component (a component perpendicular to the axial direction of the permanent magnet) of the magnetic flux density at the outer end portion is large. This is presumably because the presence of the end magnetic bodies 6B and 6C makes it easier for the magnetic flux emitted from the outer end face of the permanent magnet to bend in the vertical direction. The triple coils 2A, 2B, and 2C are wound so as to go around the outer peripheral side of the movable magnet 3, and the left end of the permanent magnet 5A constituting the movable magnet 3, the opposite end of the permanent magnets 5A and 5B, And the magnetic flux from the rightmost magnetic pole of the permanent magnet 5B. These coils 2
A, 2B, and 2C are connected so that current flows in different directions with the boundary between the magnetic poles of the permanent magnets 5A and 5B (the boundary between the magnetic poles is not necessarily at the magnetic pole intermediate position if the magnetic pole is between the magnetic poles). May be.). Although illustration is omitted,
The coils 2A, 2B, 2C are usually mounted on guide cylinders for guiding the magnet movable body 3 movably in the axial direction.
The positional relationship between the coils 2A, 2B, 2C and the magnet movable body 3 is such that at most of the movable positions of the magnet movable body 3, the currents flowing through the respective coils are opposite to each other with the boundary between the permanent magnet magnetic poles. Set as follows.

The structure of the magnet movable body 3 in FIG.
As shown in FIG. 2, two permanent magnets are made to face each other with the same polarity, an intermediate soft magnetic material is arranged between the permanent magnets, and an end soft magnetic material is arranged on the outer end surfaces of the permanent magnets on both sides. In the case of FIG. 10, the vertical component of the surface magnetic flux density in the region corresponding to the position of the end soft magnetic material is somewhat superior to that of FIG. 9 without the end soft magnetic material (in the case of only one permanent magnet). Of course, it is superior to that of FIG. 8).

As described above, the two permanent magnets 5A and 5B are made to oppose each other with the same polarity, and the intermediate soft magnetic body 6A is placed between the permanent magnets.
End soft magnetic bodies 6B, 6 are provided on the outer end faces of the permanent magnets 5A, 5B.
The magnet movable body 3 provided with C can further increase the magnetic flux component perpendicular to the longitudinal direction of the magnet movable body 3 that can contribute to the thrust based on Fleming's left-hand rule, and has three coils 2
Since A, 2B, and 2C effectively interlink with the magnetic flux of all the magnetic poles of the permanent magnet, by applying a current to the three coils 2A, 2B, and 2C alternately to generate a magnetic field of opposite polarity,
A large thrust that cannot be reached in the conventional example of FIG. 6 can be generated, and a thrust that exceeds the thrust of the reference example of FIG. 7 can be generated. When the current of each coil is reversed, the direction of the thrust of the magnet movable body 3 is also reversed. When an alternating current is passed, it works as a vibrator that repeats oscillation at a constant cycle.

In the case of FIG. 5 according to the present invention, for example, a rare earth permanent magnet having a diameter of 7 mm and a length of 7 mm is used as the magnet movable body 3.
Using a single piece (the performance of the rare earth permanent magnet is assumed to be the same as the conventional example), and a middle soft magnetic body with a length of 2 mm between them, and a soft magnetic body with a length of 2 mm on the outer end face of each permanent magnet The three coils 2A and 2A which are arranged so as to have the same power consumption as the conventional example in FIG. 6 and the reference example in FIG.
When a total of 5 W of electric power is input to B and 2C (117 mA
The thrust F3 generated when the current of (1) was applied was 235 (gf) as shown in the table above. This is 165 of the conventional example.
The thrust is 1.42 times as large as (gf) and 1.1 times as large as 215 (gf) in the reference example, indicating that the configuration of the present invention is effective for improving the thrust. Therefore, it is possible to obtain a movable magnet type actuator that can generate a large thrust with a small size and a small current.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a movable magnet type actuator according to the present invention will be described below with reference to the drawings.

FIGS. 1 and 2 show a first embodiment of the present invention. In these figures, reference numeral 1 denotes a cylindrical yoke made of a soft magnetic material, and a triple coil 2A,
2B and 2C are arranged and fixed to the cylindrical yoke 1 with an insulating member such as an insulating resin constituting a guide cylinder 4 for slidably guiding the magnet movable body 3. Magnet movable body 3
Are two columnar rare earth permanent magnets 5A,
5B, a cylindrical intermediate soft magnetic body 6A fixed between the permanent magnets 5A, 5B, and cylindrical end soft magnetic bodies 6B, 6C fixed to the outer end surfaces of the permanent magnets 5A, 5B. And the permanent magnets 5A and 5B and the soft magnetic material 6
A, 6B and 6C are integrated with each other by an adhesive or the like.
The three coils 2A, 2B, 2C are composed of permanent magnets 5A, 5A.
The wires are connected such that currents flow in different directions from the boundary between the magnetic poles of B. That is, the center coil 2B surrounds the ends including the intermediate soft magnetic body 6 and the N poles of the permanent magnets 5A and 5B, and the coils 2A and 2C on both sides surround the permanent magnets 5A and 5B.
, And the direction of the current flowing through the central coil 2B and the coils 2A, 2C on both sides.
(See N and S attached to each coil in FIG. 1). The thickness of the end soft magnetic bodies 6B and 6C is set to about 1/2 to 1 times the thickness of the intermediate soft magnetic body 6A.

In the first embodiment, each of the coils 2A, 2A
Since the cylindrical yoke 1 made of a soft magnetic material is provided on the outer peripheral side of B and 2C, the vertical component of the surface magnetic flux density of the magnet movable body 3 is further increased as compared with the case of FIG. For this reason, the magnetic flux component perpendicular to the longitudinal direction of the magnet movable body 3 that can contribute to the thrust based on Fleming's left-hand rule can be increased, and the triple coils 2A and 2 wound around the magnet movable body 3 in an annular shape.
A larger thrust can be generated by supplying a current in a direction in which magnetic fields of opposite polarities are alternately generated in B and 2C. For example, two rare earth permanent magnets each having a diameter of 7 mm and a length of 7 mm are used as the magnet movable body 3 (the performance of the rare earth permanent magnets is assumed to be the same as the conventional example), and an intermediate soft magnetic body having a length of 2 mm is provided between the two. 6 and three coils 2A, 2B, 2 which are formed so as to have the same power consumption as the conventional example in FIG. 6 and the reference example in FIG.
The thrust F4 generated when a total of 5 W of electric power was input to C (when a current of 117 mA was passed) was 275 (gf) as shown in the above table. This is 1.17 times the 235 (gf) of the soft magnetic material without the cylindrical yoke, and it can be seen that the thrust can be further improved. The direction of thrust F4 is
In the polarity of FIG. 1, the direction in which the magnet movable body 3 moves to the right direction is reversed. If the current of each coil is reversed, the direction of the thrust of the magnet movable body 3 is also reversed. When an alternating current is passed, it works as a vibrator that repeats oscillation at a constant cycle. Ma
The center coil 2B is smaller than the end coils 2A and 2C.
The same pole pair of permanent magnets 5A and 5B
Magnetic flux distribution on the opposite side (more than the magnetic flux at the end,
Area is wide). Also,
The current density is high due to the narrow width of the end coils 2A and 2C.
The magnetic flux distribution on the end side of the permanent magnets 5A and 5B (multiple magnetic flux
Thrust can be generated effectively between
You.

The end soft magnetic material 6B or 6C has
The output take-out pin 7 may be provided integrally as shown by the imaginary line in FIG. 1 so that the thrust can be transmitted to the outside. However, when used as a vibrator for a pager or the like, the pin 7 is unnecessary.

Also, as shown by a virtual line in FIG.
May be fixed to one or both ends of the yoke 1 to restrict the moving range of the magnet movable body 3. in this case,
The magnet movable body 3 stops in a state of being attracted to the soft magnetic material attracting plate 8.

FIG. 3 shows a second embodiment of the present invention. In this figure, a magnet movable body 23 is composed of two columnar rare earth permanent magnets 5A and 5B arranged in the same pole opposition, and these permanent magnets 5A and 5B.
A, a columnar intermediate soft magnetic body 6A arranged between 5A and 5B
And a cylindrical end soft magnetic body 6B, 6C disposed on the outer end face of the permanent magnets 5A, 5B.
4 and integrated by caulking the end of the holder 24 or bonding each member to the holder 24. Also, the end soft magnetic body 6 of the magnet movable body 23
Non-magnetic pins 25 are integrally provided on B and 6C. That is, the non-magnetic pin 25 is fixedly integrated with the center of the flat cylindrical end soft magnetic members 6B and 6C by welding, bonding, or the like. On the other hand, a support plate 28 is fixed to both ends of the cylindrical yoke 1 and the guide cylinder 4 made of a soft magnetic material.
The non-magnetic pin 25 penetrates the center hole 26. Both non-magnetic pins 25 are slidably supported by a center hole 26. The annular permanent magnets 27 are fixed inside the two support plates 28 so as to generate a repulsive force between the outer end faces of the permanent magnets 5A and 5B and the magnetic poles. For example, in FIG. 3, the S pole of the annular permanent magnet 27 faces the S pole on the outer end surfaces of the permanent magnets 5A and 5B. The other configuration is the same as that of the first embodiment.

According to the second embodiment, each coil 2A,
2B, 2C, the magnet movable body 2
Reference numeral 3 denotes a magnet movable body which is returned to an intermediate position in the cylindrical yoke 1 by the repulsive force of the permanent magnets 5A and 5B and the left and right annular permanent magnets 27, and is supplied with a DC current to each of the coils 2A, 2B and 2C. 23 can be driven to one side. When an alternating current is applied, the magnet movable body 23 reciprocates and operates as a vibrator. However, the magnet movable body 23 is displaced to some extent and the repulsive force of the permanent magnets 5A and 5B and the left and right annular permanent magnets 27 is obtained. Return to the intermediate position, the magnet movable body 2
3 can be prevented from colliding with the support plate 28 or the annular permanent magnet 27 and generating an impact sound. In addition, the permanent magnets 5A, 5A
B, since each soft magnetic body 6A, 6B, 6C is housed and integrated in the holder 24, the integration of those parts is assured, the durability is improved, and the life can be extended.

FIG. 4 shows a third embodiment of the present invention. In this figure, the end soft magnetic body 6B of the magnet movable body 23,
6C is integrally provided with a pin (either non-magnetic or magnetic) 25A. That is, the pin 25A is welded to the center of the flat cylindrical end soft magnetic body 6B, 6C, respectively.
It is fixedly integrated by bonding or the like, or is formed integrally with the end soft magnetic body itself. On the other hand, a support plate 28 is fixed to both ends of the soft magnetic material cylindrical yoke 1 and the guide cylinder 4, and the pin 25A passes through a center hole 26 of the support plate 28. Both pins 25A are slidably supported by the center hole 26. A compression spring 29 is disposed between the end soft magnetic bodies 6B and 6C and the inner surface of the support plate 28. The other configuration is the same as that of the second embodiment.

According to the third embodiment, each coil 2A,
2B, 2C, the magnet movable body 2
Numeral 3 indicates that the magnet movable body 23 is driven to one side by applying a DC current to each of the coils 2A, 2B, 2C by returning to an intermediate position in the cylindrical yoke 1 by the elastic force of the left and right compression springs 29. Can be. When an AC current is applied, the magnet movable body 23 reciprocates and operates as a vibrator.
9 is returned to the intermediate position by the elastic force of the magnet movable body 23.
Can be prevented from colliding with the support plate 28 and generating an impact sound.

In each of the above embodiments, the magnet movable body is composed of two permanent magnets of the same polarity, a soft magnetic body in the middle between the two permanent magnets, and soft magnetic bodies at both ends. A magnet movable body may be constituted by at least two or more same-magnet permanent magnets, an intermediate soft magnetic body between the two permanent magnets, and an end soft magnetic body located on the outer end face of the permanent magnet at the end position. , The number of coils can be set to four or more.

In each of the embodiments, the cylindrical yoke 1 and the guide cylinder 4 are used. However, it is also possible to use a rectangular yoke or the like and a guide body, and to use a prismatic magnet movable body. Can also. In these cases as well, each coil may be wound around the outer periphery of the movable magnet.

Further, a structure in which the guide cylinder 4 is omitted and the coils 2A, 2B, 2C are insulated and fixed to the inner peripheral surface of the yoke 1 may be adopted.

Although the embodiments of the present invention have been described above, it is obvious to those skilled in the art that the present invention is not limited to the embodiments and various modifications and changes can be made within the scope of the claims. Would.

[0035]

As described above, according to the movable magnet type actuator of the present invention, a magnetic body is provided by providing a magnetic body between at least two permanent magnets having the same polarity and opposed to each other. Body longitudinal direction (permanent magnet magnetization direction)
At least three coils (middle position) so that the magnetic flux component perpendicular to
Is wider than that at the end position) so that the magnetic flux generated by each magnetic pole of the magnet movable body can be effectively linked with the magnetic flux. The thrust given based on Fleming's left hand rule can be made sufficiently large. For this reason, a small-sized, small-current, large-thrust movable magnet actuator can be realized.

[Brief description of the drawings]

FIG. 1 is a first view of a movable magnet type actuator according to the present invention.
It is a front sectional view showing an example.

FIG. 2 is a side view of the same.

FIG. 3 is a front sectional view showing a second embodiment of the present invention.

FIG. 4 is a front sectional view showing a third embodiment of the present invention.

FIG. 5 is a schematic configuration diagram showing a basic configuration of the present invention.

FIG. 6 is a configuration diagram showing a conventional example.

FIG. 7 is a configuration diagram showing a reference example proposed earlier by the present applicant.

FIG. 8 is a graph showing a vertical component (a component perpendicular to the longitudinal side surface) of a surface magnetic flux density on a longitudinal side surface (a surface parallel to the magnetization direction of the permanent magnet) of a single permanent magnet.

FIG. 9 is a graph showing a vertical component of a surface magnetic flux density on a longitudinal side surface when two permanent magnets are placed in the same pole opposing state via a soft magnetic material.

FIG. 10 is a graph showing the vertical component of the surface magnetic flux density on the longitudinal side surface when two permanent magnets are placed in the same pole opposing state via an intermediate soft magnetic material and end soft magnetic materials are arranged on both sides.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cylindrical yoke 2A, 2B, 2C Coil 3, 23 Magnet movable body 4 Guide cylinder 5A, 5B Permanent magnet 6A Intermediate soft magnetic body 6B, 6C End soft magnetic body 24 Non-magnetic holder 7, 25, 25A Pin

────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shigeo Saito 1-13-1 Nihonbashi, Chuo-ku, Tokyo TDK Corporation (56) References JP-A-1-321854 (JP, A) JP-A Sho56 -1763 (JP, A) Actually open 1979-133316 (JP, U) Actually open 1979-133314 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) H02K 33/16 H01F 7/16

Claims (4)

(57) [Claims] An intermediate magnetic body is provided between at least two permanent magnets of the same polarity facing each other, and an end magnetic body is provided on outer end surfaces of permanent magnets located at both ends to form a magnet movable body. The magnet movable body is movably provided inside at least three coils, and the magnet movable body is provided inside the at least three coils .
The middle position is wider than the end position,
The arrangement is such that the magnetic flux from the opposite end of the permanent magnet is linked.
The end position is from the end magnetic pole of the permanent magnet.
A movable magnet type actuator, wherein each coil is connected so that currents flow in different directions with magnetic poles of each permanent magnet as a boundary. 2. A movable magnet type actuator according to claim 1, wherein a magnetic yoke is provided on an outer peripheral side of said coil to constitute a magnetic circuit for increasing a magnetic flux component in a direction perpendicular to a magnetization direction of said permanent magnet. . 3. The movable magnet type actuator according to claim 1, wherein the permanent magnet, the intermediate magnetic body, and the end magnetic body are integrated by a non-magnetic holder to constitute the movable magnet body. 4. The movable magnet type actuator according to claim 1, wherein said magnet movable body is provided with an output take-out pin.