JP3750479B2 - Vibration type linear actuator - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a vibration type linear actuator.
[0002]
[Prior art]
As a vibration type linear actuator, as shown in FIG. 11A, a movable element 1 composed of a permanent magnet 11 and a yoke 12, a stator 2 composed of a stator 20 and windings 21 and 21, and a resonance spring system. In this type of conventional vibration type linear actuator, the permanent magnet 11 is magnetized in the direction perpendicular to the surface facing the stator 2. Further, with respect to the stator 2 which is U-shaped and configured with two poles, the permanent magnet 11 of the mover 1 has a magnetic pole on the surface facing the stator 2 having one pole in the center and different poles on both sides in the vibration direction. It has been arranged. FIG. 11B shows the magnetic flux passing through the magnetic circuit.
[0003]
[Problems to be solved by the invention]
In this case, the thrust characteristics are almost flat with respect to the displacement of the mover. However, since the magnetization direction is perpendicular to the stator facing surface, the magnetic flux tends to enter perpendicular to the stator. There is a problem that the suction force acts so much that the thrust in the vibration direction cannot be taken too much. Incidentally, P1 in FIG. 4 indicates the thrust characteristic in the above conventional example.
[0004]
The present invention was invented in view of the above-described problems of the conventional example, and an object of the present invention is to provide a vibration type linear actuator capable of ensuring a sufficiently large thrust.
[0005]
[Means for Solving the Problems]
Accordingly, the present invention is a linear actuator that includes a mover composed of a permanent magnet and a yoke, a stator composed of a stator and a winding, and a resonance spring system, and causes the mover to reciprocate. The mover includes a permanent magnet facing one of the two poles at both ends of the U-shaped stator and a permanent magnet facing the other pole, and is arranged in the vibration direction and magnetized in the vibration direction. The two permanent magnets are characterized in that the opposing surfaces have the same polarity.
[0006]
At this time, it is preferable that the center of the thickness of the permanent magnet in the magnetization direction is opposite to the center of the stator pole.
[0007]
The thickness in the magnetization direction of the permanent magnet may be narrower or wider than the pole width of the opposing stator, but the thickness in the magnetization direction of the permanent magnet is narrower on the opposite side of the stator than the pole width of the opposing stator, It may be wider on the stator side, or may be wider on the side opposite to the stator than the pole width of the opposing stator and narrower on the stator side.
[0008]
The height of the permanent magnet is preferably substantially the same as the height of the yoke. At this time, the yoke may be separated by the permanent magnet.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an example of an embodiment of the present invention will be described in detail with reference to the drawings. FIGS. 2 and 3 show a vibration type linear actuator used as a driving source for a reciprocating electric shaver, and 1a and 1b in the figure are movable. Each of them is composed of a yoke (back yoke) 12 made of a magnetic material, a permanent magnet 11 bonded and fixed to the yoke 12, and a skeleton member 10 for integrating them.
[0010]
The stator 2 is a permanent magnet in which a coil bobbin 23 as an insulator is attached to two magnetic poles of a U-shaped yoke 21 in which a sintered body of magnetic material and an iron plate of magnetic material are laminated, and a winding 22 is applied thereon. It is formed as a magnet and is fixed to the chassis 4.
[0011]
The stator 2 is fixed by fixing the upper end portion of the connecting plate 5 to the chassis 4 by the support plate 40 and fixing the lower end portion of the connecting plate 5 to the movers 1a and 1b by the support plate 41. The mover 1a, 1b is connected to the chassis 4, and at this time, the stator 2 is connected by a connecting plate 5 made of a spring material (plate spring) that can be displaced only in the reciprocating direction of the mover 1a, 1b. It faces the permanent magnet 11 provided on the movers 1a and 1b with a predetermined gap therebetween.
[0012]
Further, a pair of spring members 30 and 30 made of compression coil springs are arranged in the reciprocating direction of the movers 1a and 1b between the spring receiver 14 of the mover 1a and the spring receiver 15 on the inner surface of the mover 1b. The The spring materials 30 and 30 function as the resonance spring system 3 of the mover 1 (1a and 1b).
[0013]
In the linear actuator configured as described above, the permanent magnets 11 and 11 provided on the movers 1a and 1b are driven in the reciprocating direction by alternating the direction of the current flowing through the winding 22 of the stator 2. . In addition, since the arrangement of the magnetic poles of the permanent magnet 11 provided on the mover 1a and the arrangement of the magnetic poles of the permanent magnet 11 provided on the mover 1b are reversed, the two movers 1a and 1b are reciprocatingly different in phase by 180 °. I do. At this time, the spring members 30 and 30 are compressed and expanded, and both the movers 1a and 1b operate as a spring vibration system.
[0014]
Here, as shown in FIG. 1, in the vibration type linear actuator according to the present invention, a pair of permanent magnets 11 and 11 are disposed in the yoke 12 so as to face the two magnetic poles of the U-shaped stator 18, and adjacent to each other. The matching permanent magnets are magnetized in the amplitude direction so that the opposing surfaces are of the same type. The permanent magnet 11 has the same amount of permanent magnets as the conventional one. The magnetic flux passing through the magnetic circuit is shown in FIG.
[0015]
Compared to the conventional magnetic circuit, the magnetic flux component acting in the direction of increasing the thrust is relatively increased with respect to the magnetic flux component acting in the direction of reducing the thrust, and the thrust is increased, which is the same as the conventional permanent magnetic circuit. A large thrust can be obtained by the amount of magnets.
[0016]
Now, the total permanent magnet amount of the permanent magnet 11 is the same as that of the conventional example, and as shown in FIG. 5, the outer dimensions of the yoke 12 are the same as those of the portion constituted by the yoke 12 and the permanent magnet 11 of the conventional example. When the outer dimensions are the same, the thrust characteristics are indicated by P2 in FIG. Further, in order to obtain a thrust equivalent to that of the conventional example, a permanent magnet amount of about 60% of the conventional permanent magnet amount is sufficient.
[0017]
In addition, as shown in FIG. 6, if the center of the thickness of the permanent magnet 11 in the magnetization direction is opposed to the center of the stator pole, the thrust can be further increased.
[0018]
Further, in the case shown in FIG. 6, the thickness of the permanent magnet 11 in the magnetization direction is made narrower than the pole width of the opposing stator 21, and the thrust characteristic in this case is indicated by P3 in FIG. As the thrust becomes larger than before, the thrust characteristics with respect to the displacement in the vibration direction are almost flat, and there is no variation in the thrust with respect to the displacement in the vibration direction. Thrust can be obtained.
[0019]
In the configuration shown in FIG. 7, the thickness of the permanent magnet 11 in the magnetization direction is wider than the pole width of the opposing stator 21, and the center of the permanent magnet 11 in the magnetization direction is opposed to the center of the stator pole. I am letting. In this case, the thrust characteristic indicated by P4 in FIG. 4 can be obtained. In addition, the thrust characteristic P4 has a large maximum thrust, and the thrust characteristic with respect to the displacement of the mover 1 is tilted. The thrust increases as the displacement of the mover 1 in the vibration direction increases. This force increases the amplitude of the mover 1 in order to counteract the force of the resonance spring 30 that attempts to return the mover 1 to the position where the displacement from the stator 2 pole center as the initial position is zero. Can do.
[0020]
As shown in FIG. 8, the thickness in the magnetization direction of the permanent magnet 11 that opposes the center of the thickness in the magnetization direction and the center of the stator pole is opposite to that of the stator 21 compared to the pole width of the stator 21. The trapezoid is narrow on the side and wide on the stator 21 side. In this case, the thrust characteristic indicated by P5 in FIG. 4 can be obtained, and the inclination of the thrust characteristic with respect to the displacement of the mover 1 becomes gentler than that shown in FIG.
[0021]
As shown in FIG. 9, the thickness in the magnetization direction of the permanent magnet 11 that opposes the center of the thickness in the magnetization direction and the center of the stator pole is opposite to that of the stator 21 compared to the pole width of the stator 21. It is good also as trapezoid shape which becomes wide at the side and becomes narrow at the stator 21 side. In this case, the thrust characteristic is indicated by P6 in FIG. 4, and the thrust can be increased while the thrust characteristic with respect to the displacement of the mover 1 is made flat. Therefore, it has the advantage in what is shown in FIG. 6 and the advantage in what is shown in FIG.
[0022]
In the case shown in FIG. 10, the height of the permanent magnet 11 in which the center of the thickness in the magnetization direction is opposed to the center of the stator pole and the thickness in the magnetization direction is narrower than the pole width of the facing stator 21. Is substantially the same as the height of the yoke 12. The thrust characteristic at this time is indicated by P7 in FIG. Since the magnetic flux short circuit by the yoke 12 at the upper end or the lower end of the permanent magnet 11 can be avoided, the maximum thrust can be obtained when the yoke 12 is integrated. In particular, when the yoke 12 is separated by the permanent magnet 11, the permanent magnet space can be maximized within the yoke 12, so that the maximum thrust can be generated.
[0023]
【The invention's effect】
As described above, in the first aspect of the present invention, the movable element is composed of the permanent magnet and the yoke, the stator and the stator, and the resonance spring system. in the linear actuator to perform a husband with a permanent magnet opposed to two months of one permanent magnet faces the pole of the other pole of the pole at both ends of the U-shaped stator armature is provided, arranged in the vibration direction s The permanent magnets magnetized in the vibration direction can increase the magnetic flux that acts as a thrust because the opposing surfaces have the same polarity, and obtain a large thrust. Can do.
[0024]
In the invention of claim 2, since the center of the thickness in the magnetization direction of the permanent magnet is opposed to the center of the stator pole, the thrust can be further increased.
[0025]
In the invention of claim 3, since the thickness in the magnetization direction of the permanent magnet is narrower than the pole width of the opposing stator, the thrust characteristic with respect to displacement can be made substantially flat while increasing the thrust. .
[0026]
In the invention of claim 4, since the thickness in the magnetization direction of the permanent magnet is wider than the pole width of the opposing stay, the thrust can be greatly improved, and the thrust characteristic with respect to the displacement can be reduced. It can be tilted so that the thrust increases as it goes to the end, and for this reason, the amplitude can be increased against the spring force for resonance.
[0027]
In the invention of claim 5, the thickness in the magnetization direction of the permanent magnet is narrower on the side opposite to the stator than the pole width of the opposing stator and wider on the stator side. Thus, the inclination of the thrust characteristic with respect to the displacement can be made gentle.
[0028]
In the invention of claim 6, since the thickness in the magnetization direction of the permanent magnet is wider on the opposite side of the stator than the opposing stator and is narrower on the stator side, the thrust characteristics against displacement are made flat. However, a large thrust can be obtained, and the advantages of the invention of claim 3 and the invention of claim 4 can be combined.
[0029]
In the invention of claim 7, since the height of the permanent magnet is substantially the same as the height of the yoke, it is possible to avoid magnetic flux short-circuiting by the yoke at the upper end or the lower end of the permanent magnet. Can be obtained.
[0030]
In the invention of claim 8, since the permanent magnet space can be maximized in the yoke, the maximum thrust can be generated.
[Brief description of the drawings]
FIGS. 1A and 1B show a main part of an example of an embodiment of the present invention, where FIG. 1A is a schematic front view, and FIG. 1B is a magnetic circuit diagram showing a flow of magnetic flux.
FIG. 2 is a perspective view showing the overall configuration of the above.
FIG. 3 is an exploded perspective view of the above.
FIG. 4 is a characteristic diagram showing thrust characteristics.
FIG. 5 is a schematic front view of another example.
FIG. 6 is a schematic front view of still another example.
FIG. 7 is a schematic front view of another example.
FIG. 8 is a schematic front view of still another example.
FIG. 9 is a schematic front view of a different example.
FIG. 10 is a schematic front view of another example.
11A and 11B show a conventional example, in which FIG. 11A is a schematic front view, and FIG. 11B is a magnetic circuit diagram showing the flow of magnetic flux.
[Explanation of symbols]
1 Moment 2 Stator 3 Resonant Spring System 11 Permanent Magnet 12 Yoke 21 Stator 22 Winding

Claims (8)

A linear actuator comprising a mover composed of a permanent magnet and a yoke, a stator composed of a stator and a winding, and a resonance spring system. 2 months of a permanent magnet that faces the permanent magnet and the other pole facing the one pole of the pole with the armature, the two permanent magnets which are magnetized in each vibration direction together aligned in the vibration direction of the Is a vibration type linear actuator characterized in that the opposing surfaces have the same polarity.   2. The vibration type linear actuator according to claim 1, wherein the center of the thickness in the magnetizing direction of the permanent magnet faces the center of the stator pole.   3. The vibration type linear actuator according to claim 1, wherein a thickness of the permanent magnet in the magnetization direction is narrower than a pole width of the opposing stator.   3. The vibration type linear actuator according to claim 1, wherein a thickness of the permanent magnet in the magnetization direction is wider than a pole width of the opposing stay.   3. The vibration type linear actuator according to claim 1, wherein the thickness of the permanent magnet in the magnetization direction is narrower on the side opposite to the stator than the pole width of the opposing stator and wider on the stator side.   3. A vibration type linear actuator according to claim 1, wherein the thickness of the permanent magnet in the magnetizing direction is wider on the side opposite to the stator than the pole width of the opposing stator and narrower on the stator side.   The vibration type linear actuator according to claim 1, wherein the height of the permanent magnet is substantially the same as the height of the yoke.   8. The vibration type linear actuator according to claim 7, wherein the yoke is constituted by being separated by a permanent magnet.

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