JP2003339147A - Linear actuator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a linear actuator which can enhance reliability and can easily realize performance improvement. <P>SOLUTION: This linear actuator is equipped with a stator 12; a mover 13 which is provided capably of reciprocation to the stator; a pair of first permanent magnets 14 and 15 which oppose the mover side by side in the direction of reciprocation and have their magnetic poles, arranged orthogonal to the direction of reciprocation and are provided at the stator with the sides of each other magnetic poles reversed; a pair of second permanent magnets 16 and 17 which oppose the mover 13 side by side in the direction of reciprocation and have their magnetic poles arranged orthogonally to the direction of reciprocation, being registered in the direction of reciprocation with the first permanent magnets 14 and 15 in a pair, with the sides of each other's magnetic poles being reversed; and a coil 18 which is provided in the stator 12, and for the first permanent magnets in pair and the second permanent magnets in pair, the magnetic poles opposed to the mover are reversed between the permanent magnets, whose positions are registered in the direction of reciprocation. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a linear actuator, and more particularly to improvement of reliability and performance thereof.

[0002]

2. Description of the Related Art A linear actuator is used as a compressor motor or the like because it can be driven with a small loss by resonating with a spring. Since a compressor using this linear actuator can exhibit excellent performance such as high efficiency, it is expected to be used as a refrigerator, a freezer, or an air conditioner.

As a linear actuator, there is a voice coil motor. This voice coil motor is driven by a force generated in a coil by passing a current through the coil in a magnetic field created by a permanent magnet, and is also called a movable coil type in which a mover including the coil moves.

As another linear actuator,
There is also a structure in which a permanent magnet and a coil are exchanged with respect to the above-mentioned movable coil type, and a movable element including a permanent magnet is called a movable magnet type.

[0005]

By the way, in the above-mentioned movable coil type, since a coil is included in the mover, it is necessary to pass an electric current through the mover. Movement may cause disconnection,
There was a problem of poor reliability.

Further, in the above-mentioned movable magnet type, the weight of the permanent magnet is increased when trying to obtain a high magnetic flux density in order to improve the performance, and as a result, the weight of the mover is increased. Therefore, there is a problem that the performance cannot be improved as desired.

Therefore, it is an object of the present invention to provide a linear actuator which can improve reliability and easily improve performance.

[0008]

In order to achieve the above object, a linear actuator according to claim 1 of the present invention comprises:
A stator, a mover having an iron member at least in part and provided so as to be reciprocable with respect to the stator, and facing the iron member and adjoining each other in the state of being adjacent to each other in the reciprocating direction. A pair of first permanent magnets provided on the stator in a state where the magnetic poles are arranged orthogonally to the direction of movement and the arrangement of the magnetic poles is reversed, and the reciprocating motion is performed with respect to the first pair of permanent magnets. The magnetic poles are aligned in the direction of movement, and the magnetic poles are arranged adjacent to each other in the direction of the reciprocal movement, facing the iron member and orthogonal to the direction of the reciprocal movement, and the arrangement of the magnetic poles is reversed. A second pair of permanent magnets provided on the stator in a state and a coil provided on the stator, wherein the first pair of permanent magnets and the second pair of permanent magnets are Front with permanent magnets that are aligned in the direction of reciprocation It is characterized by that a magnetic pole is opposed to the iron member reversed.

As a result, when the current of the coil on the stator side flows in one direction, for example, the stator, one permanent magnet of the first pair of permanent magnets, the iron member, and the second pair of permanent magnets. Among the permanent magnets of the first pair of permanent magnets in the reciprocating direction, a magnetic flux is formed by one of the permanent magnets and the loop of the stator, and the current of the coil on the stator side is switched to the opposite direction. In the flowing state, magnetic flux is formed by the stator, the other permanent magnet of the second pair of permanent magnets, the iron member, the other permanent magnet of the first pair of permanent magnets, and the loop of the stator. . As a result, when the direction of the current of the coil on the stator side is switched alternately, the side of the stator side that guides the magnetic flux to the iron member in the first pair of permanent magnets and the second pair of permanent magnets of the stator side of the mover is changed. The direction of reciprocation is alternately switched, and the iron member, that is, the mover is reciprocated. Since the coil and the permanent magnet are both provided on the stator side in this manner, it is not necessary to feed power to the mover side, and the moving mover does not cause a disconnection in the feed line to the coil. . Further, even if the weight of the permanent magnet increases when trying to obtain a high magnetic flux density in order to improve the performance, the weight of the mover does not increase. Further, since the mover has no magnet, the work of magnetizing the mover becomes unnecessary. In addition, since the mover is moved by the loop of the magnetic flux described above, a part of the stator on the side opposite to the permanent magnet of the mover may not be arranged as a back yoke.

A linear actuator according to a second aspect of the present invention is the linear actuator according to the first aspect, wherein the set of the first pair of permanent magnets and the second pair of permanent magnets is positioned in the reciprocating direction. The feature is that a plurality of sets are provided together.

As described above, since a plurality of sets of the first pair of permanent magnets and the second pair of permanent magnets are provided so as to be aligned in the reciprocating direction of the mover, a stronger permanent magnet is provided. The magnetomotive force due to the magnetic field and the current can be obtained.

According to a third aspect of the present invention, in the linear actuator according to the first or second aspect, the pair of the first pair of permanent magnets and the second pair of permanent magnets is in the reciprocating direction. A plurality of sets are provided adjacent to each other, and the iron member is characterized in that a plurality of convex portions protruding in the direction of the permanent magnet are provided adjacent to each other in the reciprocating direction.

As described above, a plurality of sets of the first pair of permanent magnets and the second pair of permanent magnets are provided adjacent to each other in the reciprocating direction of the mover. Since the member is provided with a plurality of convex portions that are adjacent to each other in the reciprocating direction of the mover and project toward the permanent magnet, the stroke is reduced, but the thrust can be increased in proportion to the number of teeth. .

According to a fourth aspect of the present invention, in the linear actuator according to any one of the first to third aspects, the stator is made of laminated steel plates laminated in the reciprocating direction. I am trying.

As described above, since the stator is made of laminated steel plates laminated in the reciprocating direction of the mover, the eddy current loss can be reduced as compared with the case where the stator is machined from a solid material. Therefore, the hysteresis loss can be reduced as compared with the case of being formed by sintering or a dust core. In addition, especially when the size of the stator is increased, the manufacturing becomes easier as compared with the cutting and sintering from the solid material.

[0016]

DETAILED DESCRIPTION OF THE INVENTION A linear actuator according to a first embodiment of the present invention will be described below with reference to FIGS.

The linear actuator 11 of the first embodiment
Is a yoke (stator) 12, a mover 13 reciprocally provided inside the yoke 12, and a pair of permanent magnets (first pair of permanent magnets) 1 fixed to the yoke 12.
4 and 15, a pair of permanent magnets (second pair of permanent magnets) 16 and 17 fixed to the yoke 12, and two coils 18 fixed to the yoke 12.

The yoke 12 has a rectangular tube shape as a whole by forming a through hole 21 at the center position thereof. The through hole 21 has a shape in which the inner peripheral surface of the cylinder is cut in two places in parallel with the axis of the cylindrical face at predetermined intervals, and the two cylindrical face portions 22 facing each other in a separated state and the respective cylindrical face portions 22. A flat surface portion 23 extending outward from both end edge portions along a direction connecting the cylindrical surface portions 22 to each other, and an orthogonal edge to the flat surface portion 23 from an end edge portion on the opposite side to each cylindrical surface portion 22 of each flat surface portion 23. A flat surface portion 24 extending outward,
It has a planar inner surface portion 25 that extends in the direction connecting the cylindrical surface portions 22 and connects the corresponding ones of the respective planar portions 24. Here, the two cylindrical surface portions 22
Have the same diameter, the same length, and the same width, and are arranged coaxially.
Further, the flat surface portion 23, the flat surface portion 24, and the inner surface portion 25 are respectively formed with concave portions 30 that are recessed in the radial direction on both sides in the circumferential direction of each cylindrical surface portion 22.

The yoke 12 has the two cylindrical surface portions 22, the four flat surface portions 23, and the four flat surface portions 24.
And a two-sided inner surface portion 25, a thin steel plate is punched by a press to form a base member 27.
A plurality of laminated steel sheets 7 are laminated in the through direction of the through hole 21 while being aligned and joined together. Also,
The yoke 12 is not provided with a back yoke extending inward of the mover 13.

In the yoke 12, the inner surface portions 25 and the outer surface portions 26 which are parallel to the inner surface portions 25 and are in close proximity to each other.
A portion between and is a coil winding portion 28, and as a result, such a coil winding portion 28 is provided in two places in parallel with each other. The coils 18 are wound around the coil winding portion 28 over the entire width of the inner surface portion 25, and as a result, each coil 18 is fixed to the yoke 12 in a ring shape.

The permanent magnets 14 and 15 are made of ferrite magnets having the same diameter, the same length, and the same width, which are formed by cutting a cylinder in two places at a predetermined interval in parallel with each other, and are coaxial with each other. They are arranged in a state where they are aligned in the circumferential direction and are adjacent to each other in the axial direction, and are joined and fixed to one cylindrical surface portion 22. Here, the permanent magnets 14 and 15 are of radial anisotropy in which magnetic poles are arranged in a direction orthogonal to the axial direction, and the arrangement of magnetic poles is reversed. In particular,
The permanent magnet 14 on one side in the penetrating direction of the through hole 21 is
The N pole 14a is arranged on the outer diameter side, and the S pole 14b is arranged on the inner diameter side.
The pole 15b is arranged on the outer diameter side. The permanent magnet 1
The yokes 12 are provided on both sides in the direction orthogonal to the arrangement direction of 4, 15
The concave portion 30 is arranged.

The permanent magnets 16 and 17 are made of ferrite magnets having the same diameter, the same length and the same width, which are formed by cutting the inner peripheral surface of the cylinder at two places at predetermined intervals in parallel to the axis thereof. The other cylindrical surface portions 22 are arranged coaxially with each other and aligned in the circumferential direction so as to be adjacent to each other in the axial direction.
Further, the permanent magnets 14 and 15 are spaced apart from each other on the opposite side in the circumferential direction, and are joined and fixed by aligning the positions of the through holes 21 in the axial direction. Here, these permanent magnets 16 and 17
Is a radial anisotropic type in which magnetic poles are arranged in a direction orthogonal to the axial direction, and the arrangement of magnetic poles is reversed. Specifically, in the permanent magnet 16 on one side in the penetrating direction of the through hole 21, the N pole 16a is arranged on the inner diameter side and the S pole 16b is arranged on the outer diameter side, and the permanent magnet 17 on the other side is the N pole. 17a is arranged on the outer diameter side and S pole 17b is arranged on the inner diameter side. The concave portions 30 of the yoke 12 are arranged on both sides in the direction orthogonal to the arrangement direction of the permanent magnets 16 and 17.

As described above, the pair of permanent magnets 14 and 15 and the pair of permanent magnets 16 and 17 are permanent magnets positioned in the penetrating direction of the through hole 21 and are located on the inner diameter side, that is, the mover 1.
The magnetic poles on the 3 side are reversed. That is, the permanent magnets 14 and 16 that are positioned in the penetrating direction of the through hole 21 have magnetic poles on the inner diameter side that are opposite to each other, and the permanent magnet 15 and the permanent magnet 17 that are positioned in the penetrating direction of the through hole 21 are also mutually opposite. The magnetic poles on the inner diameter side are reversed.

The mover 13 has a cylindrical shape with a through hole 31 formed at the center, and its outer diameter is slightly smaller than the inner diameters of the permanent magnets 14-17. The mover 13 is inserted inside the cylindrical surface portion 22 of the yoke 12, that is, on the inner diameter side of the permanent magnets 14 to 17 so as to be coaxial therewith while facing them, so that the through hole 21 penetrates the yoke 12. It is provided so as to be reciprocally movable in any direction. Here, the length of the mover 13 in the axial direction is shorter than the length of the through hole 21 of the yoke 12 in the penetrating direction.

The mover 13 is formed by punching a thin steel plate with a press to form an annular base member 32 having a through hole 31 inside, and a plurality of the base members 32 are formed in the through direction of the through hole 31. It is composed of laminated steel plates that are laminated and joined while aligning their positions. As a result, the mover 13 is entirely made of an iron member.

In the linear actuator 11 having the above structure, an alternating current (sine wave current, rectangular wave current) is synchronously passed through the coils 18 on both sides. Here, the coils 18 on both sides
In this case, a current flowing in the opposite direction along the penetrating direction of the through hole 21 flows through the portion closer to the mover 13 than the respective coil winding portions 28.

When no current is applied to the coils 18 on both sides, the yoke 12 and the permanent magnet 1 are made to move by the pair of permanent magnets 14 and 15 as shown by the chain double-dashed line in FIG.
5, a magnetic flux is formed by a loop connecting the mover 13, the permanent magnet 14, and the yoke 12 in this order, and the yoke 12, the permanent magnet 1 is formed by the pair of permanent magnets 16 and 17.
6, a magnetic flux is formed by a loop connecting the movable element 13, the permanent magnet 17, and the yoke 12 in this order. At this time, the mover 13 is stopped.

Then, for example, as shown in FIG. 3, one of the coils 18 (on the left side in FIG. 3) is provided with a movable element 13 thereof.
When a current is flowed to one side in the penetrating direction of the through hole 21 (a direction penetrating from the back side to the front side of the paper surface in FIG. 3), the coil winding portion 28 inside the one direction (downward direction in FIG. 3). ) Generates a magnetomotive force. Then, by the pair of permanent magnets 14 and 15 and the pair of permanent magnets 16 and 17, the yoke 12 and the pair of permanent magnets 1 are provided on the one coil 18 side as shown by the chain double-dashed lines in FIGS. 3 and 4.
The position of the permanent magnet 15 on one side (the back side of the paper in FIG. 3) of the Nos. 4 and 15 and the one of the permanent magnets 15 in the penetrating direction of the through hole 21 of the mover 13 and the pair of permanent magnets 16 and 17. One of the permanent magnets 17 and the yoke 1
A magnetic flux is formed by a loop connecting 2 in this order. At the same time, the coil 18 on the other side (the right side in FIG. 3) is provided in the direction opposite to the penetrating direction of the through hole 21 on the mover 13 side (the direction of penetrating from the front to the back in FIG. 3).
When an electric current is applied so as to flow in the direction, a magnetomotive force is generated in the coil winding portion 28 in one direction (downward in FIG. 3). Then,
As shown by the chain double-dashed line in FIG. 3, a pair of permanent magnets 14, 1
5 and the pair of permanent magnets 16 and 17, the yoke 12 and the pair of permanent magnets 1 also on the other coil 18 side.
One of the permanent magnets 15, 4 and 15 (on the back side of the paper in FIG. 3), the mover 13, and the pair of permanent magnets 16 and 17, one of which is in alignment with the one of the permanent magnets 15 in the penetrating direction. And a magnetic flux is formed by a loop connecting the yoke 12 in this order.

As described above, the mover 13 moves in one direction in the penetrating direction of the through hole 21 (the direction from the front side to the back side of the paper in FIG. 3, the right direction in FIG. 4).

Next, as shown in FIGS. 5 and 6, one of the coils 18 (on the left side in FIG. 5) is attached to the mover 13 thereof.
When a current is applied to the side so as to flow in the direction opposite to the direction of penetration of the through-hole 21 (the direction from the front side to the back side of the paper surface in FIG. 5), the coil winding portion 28 inside the one direction (upward direction in FIG. 5) ) Generates a magnetomotive force. Then, as shown by the two-dot chain line in FIGS. 5 and 6, the pair of permanent magnets 14, 15
And the pair of permanent magnets 16 and 17, the yoke 12 and the pair of permanent magnets 14 and 1 on the one coil 18 side.
5, the other permanent magnet 1 (the front side of the drawing in FIG. 5), the mover 13, and the pair of permanent magnets 16 and 17 in the penetrating direction of the through hole 21 of the other permanent magnet 1
4, the other permanent magnet 16 and the yoke 12 which are aligned with
A magnetic flux will be formed by a loop connecting in this order. At the same time, in the coil 18 on the other side (right side in FIG. 5), one direction in the penetrating direction of the through hole 21 on the side of the mover 13 (direction of penetrating the paper surface from the back to the front in FIG. 5).
When an electric current is passed so as to flow in the direction, a magnetomotive force is generated in one direction (upward in FIG. 5) in the coil winding portion 28 inside thereof. Then, as shown by the chain double-dashed line in FIG. 5, by the pair of permanent magnets 14 and 15 and the pair of permanent magnets 16 and 17, the yoke 12 and the pair of permanent magnets 14 and 15 are provided on the other coil 18 side. The other of the permanent magnets 14 on the other side (the front side of the paper in FIG. 5), the mover 13, and the other of the pair of permanent magnets 16 and 17 that is aligned with the other permanent magnet 14 in the penetrating direction of the through hole 21. A magnetic flux is formed by a loop connecting the permanent magnet 16 and the yoke 12 in this order.

As a result of the above, the mover 13 moves in the direction opposite to the penetrating direction of the through hole 21 (the direction from the back side to the front side of the paper surface in FIG. 5, the left direction in FIG. 6).

The alternating currents alternately change the direction of the current flow to both coils 18, so that the above operation is repeated, and the mover 13 is moved in a predetermined direction in the through hole 21 with respect to the yoke 12. It will reciprocate with the stroke of.

According to the linear actuator 11 of the first embodiment described above, since the coil 18 is provided not on the mover 13 but on the yoke 12, it is not necessary to supply power to the mover 13 side, and the mover moves. 13 is a coil 18
There will be no breakage in the power supply line to the.
Therefore, it is possible to improve reliability for continuous operation and the like.

Further, since the permanent magnets 14 to 17 are also provided on the yoke 12 instead of the mover 13, the permanent magnets 14 to 17 are used when a high magnetic flux density is obtained in order to improve the performance.
Even if the weights of 17 and the coil 18 increase, the weight of the mover 13 does not increase. Therefore, it is possible to easily improve the performance (increase the thrust).

In addition, since the mover 13 does not have a permanent magnet, it is unnecessary to magnetize the mover 13, and
Since the suction force does not act on the mover 13 when the mover 13 is manufactured, the mover 13 is easily manufactured. Therefore, manufacturing is facilitated and cost can be reduced.

In addition, since the mover 13 is moved by the magnetic flux of the loop as described above, a part of the yoke 12 is arranged as a back yoke on the side opposite to the permanent magnets 14 to 17 of the mover 13, that is, on the inner diameter side. It can be configured not to. Therefore, the space on the side opposite to the permanent magnets 14 to 17 of the mover 13, that is, on the side of the through hole 31 can be effectively used. Specifically, the degree of freedom in designing when disposing a separate cylinder, its piston, or the like in the through hole 31 is significantly increased.

In addition, since the yoke 12 is made of laminated steel plates laminated in the reciprocating direction of the mover 13, the eddy current loss can be reduced as compared with the case where the yoke 12 is carved out from a solid material. On the other hand, the hysteresis loss can be reduced as compared with the case of being formed by sintering. Therefore,
The performance can be improved. Also, especially the yoke 12
In the case of increasing the size, the manufacturing becomes easier as compared with the cutting and sintering from the solid material. Therefore, it is possible to easily cope with the increase in size of the yoke 12 due to the increase in size of the whole.

As the permanent magnets 14 to 17, rare earth magnets such as neodymium and samarium cobalt can be used in addition to the above ferrite magnets, or plastic magnets can be used, but ferrite magnets are used. Is more preferable from the viewpoint of cost reduction.

Further, the linear actuator 11 is
It is common to incorporate a spring into the mover 13 or to resonate the spring together with a spring placed outside.
Of course, it can be used as it is.

Further, the linear actuator 11 can be used as a linear servo actuator capable of controlling the speed and position by providing a sensor for detecting the position, speed and the like and performing closed loop control.

Next, a linear actuator according to a second embodiment of the present invention will be described below with reference to FIGS. 7 and 8.

Linear actuator 51 of the second embodiment
Is a yoke (stator) 52, a mover 53 reciprocally provided inside the yoke 52, and four sets of permanent magnets (first pair of permanent magnets) 5 fixed to the yoke 52.
4, 55, four sets of permanent magnets (second pair of permanent magnets) 56, 57 fixed to the yoke 52, and eight coils 58 fixed to the yoke 52.

The yoke 52 has a cylindrical shape as a whole by forming a through hole 61 at the center thereof. The through-hole 61 has a shape in which the inner peripheral surface of the cylinder is cut at two places in parallel with the axis thereof at predetermined intervals, and has eight cylindrical surface portions 62 arranged at equal intervals in the circumferential direction. . Here, between the cylindrical surface portions 62 that are adjacent to each other in the circumferential direction, there are formed concave portions 63 that are recessed outward in the radial direction. As a result, between the concave portion 63 that are adjacent to each other in the circumferential direction, the cylindrical surface portion 62 is formed. The convex portion 64 having is formed. here,
The eight cylindrical surface portions 62 have the same diameter, the same length, and the same width, and are arranged coaxially. Although not shown in the drawings, the yoke 52 is similar to the first embodiment in that the recesses 63 at the eight locations are provided.
And a laminated steel plate in which a thin plate-shaped steel plate is punched into a shape having a convex portion 64 by a press to form a base member, and a plurality of the base members are joined in the penetrating direction of the through hole 61 while being aligned and stacked. Has become. Also, this yoke 5
2 is not provided with a back yoke having a shape extending inside the mover 53.

In the second embodiment, the coil 58 is wound around each convex portion 64 of the yoke 52 so as to extend alternately in the axial direction and the circumferential direction, and as a result, each coil 5 is wound.
A ring 8 is fixed to the yoke 52.

The permanent magnets 54, 55 are made of ferrite magnets having the same diameter, the same length, and the same width, which are formed by cutting a cylinder in two places at a predetermined interval in parallel with each other, and are coaxial with each other. The positions are aligned in the circumferential direction so as to be adjacent to each other in the axial direction, and are joined and fixed to the common cylindrical surface portion 62. Here, the permanent magnets 54 and 55 are of radial anisotropy in which magnetic poles are arranged in a direction orthogonal to the axial direction, and the arrangement of magnetic poles is reversed. In particular,
The permanent magnet 54 on one side in the penetrating direction of the through hole 61 is
The N pole 54a is arranged on the outer diameter side and the S pole 54b is arranged on the inner diameter side.
The pole 55b is arranged on the outer diameter side. Four pairs of such a pair of permanent magnets 54 and 55 are radially arranged on each of the cylindrical surface portions 32 arranged every other one in the circumferential direction.

The permanent magnets 56 and 57 are made of ferrite magnets having the same diameter, the same length, and the same width, which are formed by cutting the inner peripheral surface of the cylinder at two places at predetermined intervals in parallel to the axis thereof. Common cylindrical surface portions 62 which are coaxial with each other and are aligned in the circumferential direction and are adjacent to each other in the axial direction.
It is fixed to the joint. Here, these permanent magnets 56,
Reference numeral 57 is of radial anisotropy in which magnetic poles are arranged in a direction orthogonal to the axial direction, and the arrangement of magnetic poles is reversed.
Specifically, in the permanent magnet 56 on one side in the penetrating direction of the through hole 61, the N pole 56a is arranged on the inner diameter side, the S pole 56b is arranged on the outer diameter side, and the permanent magnet 57 on the other side is the N pole. 57a
Is arranged on the outer diameter side and the S pole 57b is arranged on the inner diameter side. And four pairs of such a pair of permanent magnets 56 and 67 are provided,
Remaining cylindrical surface portions 32 arranged every other in the circumferential direction
Are arranged in a radial pattern.

As described above, the pair of permanent magnets 54, 55 and the pair of permanent magnets 56, 57 are permanent magnets whose positions are aligned in the penetrating direction of the through hole 61.
The magnetic pole of 3 is reversed. That is, the permanent magnets 54 and the permanent magnets 56, which are positioned in the penetrating direction of the through hole 61, have magnetic poles on the inner diameter side opposite to each other, and the permanent magnets 55 and 57, which are positioned in the penetrating direction of the through hole 61, are also mutually opposite. The magnetic poles on the inner diameter side are reversed.

Here, a pair of permanent magnets 54, 55 and a pair of permanent magnets 56, 5 that are adjacent to each other and are circumferentially separated from each other are provided.
7 is a set, and a plurality of such sets, specifically, four sets are provided by aligning the positions of the through holes 21 in the penetrating direction.

The mover 53 has a cylindrical iron member 72 having a through hole 71 formed in the center thereof, and the iron member 72.
2 has a main portion 73 provided on one side in the axial direction, and the main portion 73 has a large-diameter cylindrical portion 75 that is coaxial with the iron member 72 and has the same diameter and that are adjacent to each other, and the large-diameter cylindrical portion 75. On the opposite side of the iron member 72, a small diameter cylindrical portion 76 having a diameter smaller than that of the iron member 72 and coaxially provided is provided. The iron member 7
2 and the outer diameter of the large-diameter cylindrical portion 75 are slightly smaller than the inner diameters of the permanent magnets 54 to 57. The mover 53 is inside the cylindrical surface portion 62 of the yoke 52, that is, the permanent magnets 54-
By being inserted on the inner diameter side of 57 so as to be coaxial therewith, it is provided so as to be capable of reciprocating in the penetrating direction of the through hole 61 with respect to the yoke 52. Here, the length of the iron member 72 in the axial direction is shorter than the length of the through hole 61 of the yoke 52 in the penetrating direction. Further, a bolt 78 for fixing a shaft or the like passing through the inner diameter side is screwed in the small diameter cylindrical portion 76 in the radial direction.

The main part 73 of the mover 53 is made of a synthetic resin such as engineering plastic which is a non-magnetic material, and the iron member 72 is made of a sintered material. The mover 53 is formed by insert molding of synthetic resin having the iron member 72 as a nest.

According to the linear actuator 51 of the second embodiment described above, the same effect as that of the linear actuator 11 of the first embodiment can be exhibited, and on top of that, the pair of permanent magnets 54, 55 and A pair of permanent magnets 56,
Since a plurality of sets, specifically 57 sets, are distributed, the yoke thickness can be reduced and the weight can be reduced.

Since the thickness of the mover can be reduced and the weight of the movable part can be reduced, the responsiveness is improved.

The same changes and the like as in the first embodiment can be made in the second embodiment.

Next, the linear actuator of the third embodiment of the present invention will be described below with reference to FIG. 9 focusing on the differences from the second embodiment. The same parts as those in the second embodiment are designated by the same reference numerals, and the description thereof will be omitted.

In the third embodiment, the positions of the pair of permanent magnets 54, 55 and the pair of permanent magnets 56, 57 are aligned in the circumferential direction and are adjacent to each other in the penetrating direction of the through hole 61. Another pair of permanent magnets 54 and 55 and a pair of permanent magnets 56 and 57 are provided, respectively. That is, in each pair of permanent magnets 54, 55,
A pair of permanent magnets 54 and 55 are provided so that their positions in the circumferential direction are aligned and are adjacent to each other in the penetrating direction of the through hole 61. A pair of permanent magnets 56 and 57 are provided so as to be adjacent to each other in the penetrating direction of the matching through hole 61.

Further, in the iron member, a plurality of annular convex portions 80 projecting in the direction of the permanent magnet, that is, the outer diameter side are adjacent to each other in the penetrating direction of the through hole 61, that is, the reciprocating direction of the mover 53, specifically, in a concrete manner. Are provided in two places. Here, through hole 6
The protrusion 80 on one side in the penetrating direction of the permanent magnet 5 is provided on the same side as the penetrating direction of the through hole 61 in the penetrating direction.
4, 55 and the permanent magnets 56, 57, while guiding the magnetic flux, the projection 80 on the opposite side in the penetrating direction of the through hole 61.
Guides magnetic flux between the permanent magnets 54, 55 and the permanent magnets 56, 57 provided on the same side of the through hole 61 in the penetrating direction.

According to the linear actuator 51 of the third embodiment described above, the same effect as that of the second embodiment can be exhibited, and on top of that, the pair of permanent magnets 54, 5 can be used.
Since a plurality of sets of 5 and a pair of permanent magnets 56 and 57 are provided in the reciprocating direction of the mover 53, a stronger magnetomotive force due to the magnetic field and current of the permanent magnet can be obtained. In addition, since the iron member 72 is provided with a plurality of convex portions 80 that are adjacent to each other in the reciprocating direction of the mover 53 and project toward the permanent magnets 54 to 57, the convex portion 80 is reciprocally moved. The suction force can be efficiently applied to the end surface of the movable element, and as a result, the mover can be driven with a larger force.

The configurations of all the linear actuators 11 described above may be reversed on the central axis side and the outer diameter side. For example, FIGS.
As shown in, the permanent magnets 14 and 15 and the permanent magnets 16 and 17 are arranged on the outer diameter side of the yoke 12 including the coil 18, and can be reciprocated to the outer diameter side of the permanent magnets 14 and 15 and the permanent magnets 16 and 17. The cylindrical mover 13 is provided in the. According to this structure, when the coil 18 has the same size as a whole, the coil 18 becomes smaller, so that the copper loss is reduced, the area for generating the force can be increased, and the efficiency can be improved.

[0059]

As described in detail above, the first aspect of the present invention
According to the linear actuator described, in the state where the current of the coil on the stator side flows in one direction, for example, the stator,
One of the first pair of permanent magnets, the iron member, the second
Of the pair of permanent magnets, one of the first pair of permanent magnets is aligned with one of the first pair of permanent magnets in the reciprocating direction, a magnetic flux is formed by the loop of the stator, and the current of the coil on the side of the stator changes. In the state of being switched and flowing in the opposite direction, the stator, the other permanent magnet of the second pair of permanent magnets, the iron member,
A magnetic flux is formed by the other permanent magnet of the first pair of permanent magnets and the loop of the stator. As a result, when the direction of the current of the coil on the stator side is switched alternately, the side of the stator side that guides the magnetic flux to the iron member in the first pair of permanent magnets and the second pair of permanent magnets of the stator side of the mover is changed. The direction of reciprocation is alternately switched, and the iron member, that is, the mover is reciprocated.

As described above, since the coil and the permanent magnet are both provided on the stator side, it is not necessary to supply power to the mover side, and the moving mover causes a disconnection in the power supply line to the coil. Will disappear. Therefore, reliability can be improved.

Further, even if the weight of the permanent magnet or the coil increases when a high magnetic flux density is obtained in order to improve the performance, the weight of the mover does not increase. Therefore, it is possible to easily improve the performance.

Further, since the mover has no magnet, it is not necessary to magnetize the mover. Therefore, manufacturing is facilitated and cost can be reduced.

In addition, since the mover is moved by the loop of the magnetic flux described above, a part of the stator on the side opposite to the permanent magnet of the mover may not be arranged as a back yoke. Therefore, the space on the opposite side of the permanent magnet of the mover can be effectively used.

According to the linear actuator of the second aspect of the present invention, a plurality of sets of the first pair of permanent magnets and the second pair of permanent magnets are provided with their positions in the reciprocating direction of the mover aligned. Therefore, a stronger magnetomotive force due to the magnetic field and current of the permanent magnet can be obtained.

According to the linear actuator of the third aspect of the present invention, a plurality of sets of the first pair of permanent magnets and the second pair of permanent magnets are adjacent to each other in the reciprocating direction of the mover. In accordance with this, the iron member is provided with a plurality of convex portions that are adjacent to each other in the reciprocating direction of the mover and project in the direction of the permanent magnet. It is possible to obtain a magnetomotive force due to, and it is possible to efficiently apply a suction force to the end surface of the convex portion.

According to the linear actuator of claim 4 of the present invention, the stator is made of laminated steel plates laminated in the reciprocating direction of the mover. As a result, the eddy current loss can be reduced, and the hysteresis loss can be reduced as compared with the case of being formed by sintering. In addition, especially when the size of the stator is increased, the manufacturing becomes easier as compared with the cutting and sintering from the solid material. Therefore, it is possible to improve the performance, and it is possible to easily cope with the increase in size of the stator accompanying the increase in size of the whole.

[Brief description of drawings]

FIG. 1 is a front sectional view showing a linear actuator according to a first embodiment of the present invention.

FIG. 2 is a side cross-sectional view showing the linear actuator according to the first embodiment of the present invention, and shows a state of magnetic flux when a current does not flow in the coil by a chain double-dashed line.

FIG. 3 is a front cross-sectional view showing the linear actuator of the first embodiment of the present invention, showing a state of magnetic flux when a current flows through the coil in one direction by a chain double-dashed line.

FIG. 4 is a side cross-sectional view showing the linear actuator of the first embodiment of the present invention, showing a state of magnetic flux when a current flows in one direction in a coil by a chain double-dashed line.

FIG. 5 is a front cross-sectional view showing the linear actuator of the first embodiment of the present invention, in which the state of magnetic flux when a current flows in the coil in the opposite direction is indicated by a chain double-dashed line.

FIG. 6 is a side sectional view showing the linear actuator according to the first embodiment of the present invention, and shows a state of magnetic flux when a current flows in the coil in the opposite direction by a chain double-dashed line.

FIG. 7 is a front sectional view showing a linear actuator of a second embodiment of the present invention.

FIG. 8 is a cross-sectional view taken along line XX shown in FIG. 7 showing a linear actuator according to a second embodiment of the present invention.

FIG. 9 is a sectional view taken along line XX shown in FIG. 7 showing a linear actuator according to a third embodiment of the present invention.

FIG. 10 is a front cross-sectional view showing a modified example of the linear actuator of the first embodiment of the present invention.

FIG. 11 is a side sectional view showing a modified example of the linear actuator of the first embodiment of the present invention.

[Explanation of symbols]

11 Linear actuator 12 yoke (stator) 13 mover 14,15 Permanent magnets (first pair of permanent magnets) 14a, 15a, 16a, 17a N pole (magnetic pole) 14b, 15b, 16b, 17b S pole (magnetic pole) 16,17 Permanent magnets (second pair of permanent magnets) 18 coils 51 Linear actuator 52 Yoke (stator) 53 mover 54, 55 permanent magnets (first pair of permanent magnets) 54a, 55a, 56a, 57a N pole (magnetic pole) 54b, 55b, 56b, 57b S pole (magnetic pole) 56,57 permanent magnets (second pair of permanent magnets) 58 coils 72 Iron member 80 convex

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Toshio Miki             100, Takegahana Town, Ise City, Mie Prefecture             Ise Manufacturing Co., Ltd. (72) Inventor Yutaka Maeda             100, Takegahana Town, Ise City, Mie Prefecture             Ise Manufacturing Co., Ltd. (72) Inventor Takashi Fukunaga             100, Takegahana Town, Ise City, Mie Prefecture             Ise Manufacturing Co., Ltd. (72) Inventor Kozo Furuya             100, Takegahana Town, Ise City, Mie Prefecture             Ise Manufacturing Co., Ltd. (72) Inventor Toshiya Sugimoto             100, Takegahana Town, Ise City, Mie Prefecture             Ise Manufacturing Co., Ltd. F term (reference) 5H633 BB07 GG02 GG04 HH02 HH07                       HH08 HH09 HH10 HH15 HH16                       HH18

Claims (4)

[Claims] 1. A stator, a mover having at least a part of an iron member and capable of reciprocating with respect to the stator, wherein the iron member is adjacent to each other in the reciprocating direction. A first pair of permanent magnets provided on the stator in a state where the magnetic poles are arranged to face each other and are orthogonal to the direction of the reciprocating movement, and the arrangement of the magnetic poles is opposite to each other; The magnetic poles are aligned in the reciprocating direction with respect to the magnet, and the magnetic poles are arranged so as to face the iron member and be adjacent to each other in the reciprocating direction and orthogonal to the reciprocating direction. A first pair of permanent magnets and a second pair of permanent magnets, the second pair of permanent magnets provided on the stator in a state where the arrangement is reversed, and the coil provided on the stator. The permanent magnet is aligned in the reciprocating direction Linear actuator, characterized in that in permanent magnet to each other are reversed magnetic poles to be opposite to the iron member. 2. A plurality of sets of the first pair of permanent magnets and the second pair of permanent magnets are provided with their positions in the reciprocating direction aligned. Linear actuator. 3. A plurality of sets of the first pair of permanent magnets and the second pair of permanent magnets are provided adjacent to each other in the reciprocating direction, and the iron member is provided with the permanent set. The linear actuator according to claim 1 or 2, wherein a plurality of convex portions projecting in the direction of the magnet are provided adjacent to each other in the reciprocating direction. 4. The stator is made of laminated steel plates laminated in the reciprocating direction.
The linear actuator according to any one of 1.