JP2003235232A - Linear actuator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a linear actuator in which the reliability can be enhanced and the performance can be enhanced easily. <P>SOLUTION: The linear actuator comprises a stator 12, a mover 13 having iron pieces 32 provided reciprocally with respect to the stator 12, permanent magnets 14 provided in the stator 12 while facing the iron pieces 32, and a coil 15 provided in the stator 12 wherein the iron pieces 32 and thereby the mover 13 is reciprocated by moving a magnetic flux passing through the iron pieces 32 by means of the coil 15 on the stator 12 side where the direction of current varies and the permanent magnets 14. <P>COPYRIGHT: (C)2003,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 piece that is reciprocally provided with respect to the stator, a permanent magnet provided on the stator in a state of facing the iron piece, and a coil provided on the stator. It is characterized by having and.

Thus, the iron piece is provided on the mover, the permanent magnet is provided on the stator in a state of facing the iron piece, and the coil is provided on the stator, so that the permanent magnet and the permanent magnet on the side of the stator are changed. By moving the magnetic flux passing through the iron piece with the magnet, the iron piece, that is, the mover is reciprocated. Since the coil and the permanent magnet are both provided on the stator in this manner, it is not necessary to supply power to the mover side, and the moving mover does not cause a break in the power supply line to the coil. At the same time, the weight of the mover does not increase even if the weight of the permanent magnet increases when trying to obtain a high magnetic flux density in order to improve the performance. Further, since the mover has no magnet, it is not necessary to magnetize the mover.

A linear actuator according to a second aspect of the present invention is the linear actuator according to the first aspect, wherein the permanent magnet is provided on the stator in a state where magnetic poles are arranged along the reciprocating direction. A pair of magnetic pole members are provided on both sides of the permanent magnet in the reciprocating direction.

As a result, when the direction of the electric current of the coil on the stator side is alternately changed, the iron piece through the magnetic pole members arranged on both sides of the permanent magnet having the magnetic poles arranged along the reciprocating direction of the mover. The magnetic flux introduction side is alternately changed, and the iron piece, that is, the mover is reciprocated.

According to a third aspect of the present invention, in the linear actuator according to the second aspect, the set of the permanent magnet and the pair of magnetic pole members is provided only on one side of the iron piece. It has a feature.

As described above, since the set of the permanent magnet and the pair of magnetic pole members is provided only on one side of the iron piece,
The weight can be reduced as a whole.

According to a fourth aspect of the present invention, in the linear actuator according to the third aspect, the iron piece has a cylindrical shape, and the set of the permanent magnet and the pair of magnetic pole members is with respect to the iron piece. It is characterized in that it is provided only on the outer side in the radial direction.

As described above, since the set of the permanent magnet and the pair of magnetic pole members is provided only on the outer side in the radial direction with respect to the iron piece, the radius of the iron piece, that is, the mover can be reduced. The weight can be reduced.

According to a fifth aspect of the present invention, in the linear actuator according to the third aspect, the iron piece has a cylindrical shape, and the set of the permanent magnet and the pair of magnetic pole members is with respect to the iron piece. It is characterized in that it is provided only on the inner side in the radial direction.

As described above, since the set of the permanent magnet and the pair of magnetic pole members is provided only on the inner side in the radial direction with respect to the iron piece, the radius of the permanent magnet and the pair of magnetic pole members can be reduced, and the weight of these members can be reduced. As a result, the overall weight can be reduced.

According to a sixth aspect of the present invention, in the linear actuator according to the second aspect, the set of the permanent magnet and the pair of magnetic pole members is provided on both sides via the iron piece. I am trying.

As described above, since the set of the permanent magnet and the pair of magnetic pole members is provided on both sides through the iron piece, a stronger magnetomotive force due to the magnetic field and current of the permanent magnet can be obtained.

A linear actuator according to a seventh aspect of the present invention is the linear actuator according to any one of the first to fifth aspects, wherein the stator has magnetic poles facing the iron piece on the opposite side to the permanent magnet. It is characterized in that the members are integrally molded.

As described above, since the magnetic pole member facing the iron piece on the side opposite to the permanent magnet is integrally formed with the stator,
There is no need to manufacture these separately or join them later.

According to an eighth aspect of the present invention, in the linear actuator according to any one of the first to seventh aspects, the mover is formed by insert molding of synthetic resin having the iron piece as a nest. It is characterized by being a thing.

As described above, since the mover is formed by insert molding of the synthetic resin having the iron piece as a nest, the mover including the iron piece can be formed easily and lightweight.

According to a ninth aspect of the present invention, in the linear actuator according to any one of the first to eighth aspects, the mover is supported by the stator via a ball bush. I am trying.

As described above, since the mover is supported by the stator through the ball bush, the mover can be accurately reciprocated.

According to a tenth aspect of the present invention, in the linear actuator according to any one of the first to ninth aspects, the stator is provided with a plurality of the permanent magnets in the reciprocating direction. The mover is provided with a plurality of the iron pieces in the reciprocating direction.

As described above, the stator is provided with a plurality of permanent magnets in the reciprocating direction, and the mover is provided with a plurality of iron pieces in the reciprocating direction. Thrust can be generated.

According to an eleventh aspect of the present invention, in the linear actuator according to any one of the first to tenth aspects, the stator is made of a sintered member.

As described above, since the stator is made of a sintered member, it is possible to reduce costs, improve performance (reduction of iron loss), and improve mechanical strength.

[0030]

BEST MODE FOR CARRYING OUT THE INVENTION A linear actuator according to a first embodiment of the present invention will be described below with reference to FIGS.

Linear actuator 11 of the first embodiment
Is a yoke (stator) 12, a movable element 13 reciprocally provided on the yoke 12, a permanent magnet 14 fixed to the yoke 12, and a coil 15 fixed to the yoke 12.
It has and.

The yoke 12 has a cylindrical outer cylindrical portion 17
And a thin plate ring-shaped bottom plate portion 18 provided on one end side in the axial direction of the outer cylindrical portion 17, and a ring projecting to the same side as the outer cylindrical portion 17 in the inner portion of the bottom plate portion 18 along the axial direction. And a cylindrical inner magnetic pole (magnetic pole member) 19 provided coaxially with the outer cylindrical portion 17 on the connecting portion 20.

The yoke 12 having the outer cylindrical portion 17, the bottom plate portion 18, the connecting portion 20, and the inner magnetic pole 19 is integrally formed by sintering with a sintered material which is a common magnetic material.

The coil 15 has a ring shape, and is fixed coaxially with the yoke 12 inside the corner of the boundary between the bottom plate portion 18 and the outer cylindrical portion 17 of the yoke 12.

The permanent magnet 14 is a thin plate ring having both magnetic poles, that is, an N pole 14a and an S pole 14b arranged in the axial direction, and is made of a ferrite magnet. On both sides of the permanent magnet 14 in the axial direction, projecting portions 21 that project in a substantially cylindrical shape in the axial direction are formed on the inner diameter side and have an L-shaped annular outer magnetic pole (magnetic pole member) 2.
2 and the outer magnetic pole (magnetic pole member) 23 are arranged so that the projecting portions 21 thereof project in opposite directions. The pair of outer magnetic poles 22 and 23 are also made of a sintered material. The permanent magnet 14 and the pair of outer magnetic poles 22, 23 are placed outside the yoke 12 in such a state that both sides of the permanent magnet 14 in the arrangement direction of the magnetic poles 14a, 14b are sandwiched by the annular outer magnetic poles 22, 23. By being press-fitted inside the cylindrical portion 17, the permanent magnet 14 and the pair of outer magnetic poles 22, 23 are fixed coaxially with the yoke 12 on the outer diameter side of the yoke 12.

In this fixed state, the permanent magnet 14 is the N pole 14
The a is arranged on the bottom plate portion 18 side, and one outer magnetic pole 22 is adjacent to the coil 15 in the axial direction. Further, in this fixed state, the permanent magnet 14 and the pair of outer magnetic poles 22 and 23 as a whole have the yoke 12
It is arranged coaxially with the outer cylindrical inner magnetic pole 19 and is aligned with the inner magnetic pole 19 in position and length in the axial direction. The gap portion 25 will be formed.

A bush 27 is provided on the inner peripheral side of the inner magnetic pole 19 of the yoke 12 so as to move the shaft 26 in the axial direction.
The ball bush 28 supported by
Fixed coaxially at. The mover 13 is fixed to a shaft 26 movably held by the bush 27. Then, the shaft 26 and the mover 13 reciprocate integrally with the bush 27 fixed to the yoke 12 along the axial direction.

The mover 13 has a substantially disk-shaped base portion 30 fixed to the shaft 26, and a cylindrical portion 31 provided so as to enter the annular gap portion 25 while being fixed to the shaft 26 by the base portion 30. And this cylindrical part 31
And an iron piece 32 as a cylindrical movable magnetic pole fixed to the opposite side of the base portion 30 with the same coaxial diameter. As a result, the iron piece 32 of the mover 13 is arranged coaxially within the annular gap portion 25, but the iron piece 32 is arranged so that its central position in the axial direction is substantially aligned with the central position in the axial direction of the permanent magnet 14. Has been done.

The mover 13 has a base portion 30 and a cylindrical portion 31.
Are made of synthetic resin such as engineering plastic which is a non-magnetic material, and the iron piece 32 is made of a magnetic material that is not magnetized and is made of a sintered material. The mover 13 is formed by insert molding of synthetic resin having the iron piece 32 as a nest.

As a result of the above, the mover 13 has the iron piece 32 and is supported by the yoke 12 so as to be capable of reciprocating along the axial direction (the left-right direction in each drawing), and the permanent magnet. 14 is fixed to the yoke 12 in a state of facing the outer diameter side of the iron piece 32 of the mover 13, and in a state of arranging the magnetic poles 14a and 14b along the reciprocating direction of the mover 13. Then, a pair of outer magnetic poles 22 and 23 are provided on both sides of the permanent magnet 14 in the reciprocating direction of the mover 13, and the yoke 12 includes
This means that the iron piece 32 is integrally formed with the inner magnetic pole 19 facing the opposite side of the permanent magnet 14. Furthermore, the set of the permanent magnet 14 and the pair of outer magnetic poles 22 and 23 is
It is provided only on one side with respect to the iron piece 32, and specifically, is provided only on the outer side in the radial direction with respect to the cylindrical iron piece 32.

In the linear actuator 11 having the above-described structure, when an alternating current (sine wave current, rectangular wave current) is passed through the coil 15, the current flows in a predetermined direction through the coil 15, which is indicated by a chain double-dashed line in FIG. As described above, the magnetic flux is guided from the S pole 14b to the N pole 14a side by the permanent magnet 14, so that the outer cylindrical portion 17 of the yoke 12, the outer magnetic pole 23,
Permanent magnet 14, outer magnetic pole 22, iron piece 3 of mover 13
2, the inner magnetic pole 19 of the yoke 12, the connecting portion 20, the bottom plate portion 18, and the outer cylindrical portion 17 form a magnetic flux loop in this order. As a result, the mover 12 moves in the direction of moving to the outer magnetic pole 22 side. A force F is applied to move in this direction.
On the other hand, in a state in which a current flows in the coil 15 in a direction opposite to the predetermined direction, as shown by the chain double-dashed line in FIG.
By being guided from the S pole 14b to the N pole 14a side by the permanent magnet 14, the outer cylindrical portion 17, the bottom plate portion 18, and
Connecting part 20, inner magnetic pole 19, iron piece 3 of mover 13
2, outer magnetic pole 23, permanent magnet 14, outer magnetic pole 2
2, a magnetic flux loop is formed in the order of the outer cylindrical portion 17, and as a result, the mover 12 moves in this direction due to the force F applied in the opposite direction to the outer magnetic pole 23 side.

By alternately changing the direction of the current flow to the coil 15 due to the alternating current, the above operation is repeated and the mover 13 reciprocates in the axial direction with respect to the yoke 12.

According to the linear actuator 11 of the first embodiment described above, the iron piece 32 is provided on the mover 13, and the permanent magnet 14 is provided so as to face the iron piece 32.
Is provided on the yoke 12, and the coil 15 is provided on the yoke 12 so that the direction of the current on the yoke 12 side is changed.
By moving the magnetic flux passing through the iron piece 32 with the permanent magnet 14, the iron piece 32, that is, the mover 13 is reciprocated.

As described above, since the coil 15 is provided on the yoke 12 instead of on the mover 13 side, it is not necessary to feed power to the mover 13 side, and the moving mover 13 disconnects the feed line to the coil 15. It will not be caused. Therefore, it is possible to improve reliability for continuous operation and the like.

Further, since the permanent magnet 14 is also provided on the yoke 12 side, not on the mover 13 side, even if the weight of the permanent magnet 14 is increased in order to obtain a high magnetic flux density in order to improve the performance. Therefore, the weight of the mover 13 does not increase. Therefore, it is possible to easily improve the performance (increase the thrust). In addition, in order to improve the magnetic flux density of the gap portion 25, the size of the magnet may be enlarged in the radial direction without affecting the gap portion 25 (the gap portion 25 does not expand), and the performance can be improved and the design is free. The degree improves. Moreover, since the permanent magnet 14 is eliminated in the gap portion 25, the gap portion 25 faces the iron cores,
The magnetic path length is shortened, the electromagnet magnetomotive force can be reduced, and the efficiency is increased. In addition, since the permanent magnet 14 is used, the linearity of the magnetic path is good.

In addition, since the mover 13 does not have a magnet, it is not necessary to magnetize the mover 13, and the iron piece 32 does not have an attractive force when the mover 13 is manufactured. The integral molding of 13 becomes easy. Therefore,
Manufacturing is facilitated and cost can be reduced.
Moreover, when the mover 13 is manufactured by insert molding of synthetic resin with the iron piece 32 as a nest, since the mover 13 does not have a magnet, post-processing is possible, and in addition, since the gap 25 also has no magnet. Post-processing is possible, and the accuracy of coaxial concentricity of the linear actuator 11 can be improved. As a result, the load on the bearing, that is, the ball bush 28 can be reduced, and the life of the bearing can be extended.

Specifically, when the current direction of the coil 15 on the yoke 12 side is alternately changed, both sides of the permanent magnet 14 in which the magnetic poles 14a and 14b are arranged along the reciprocating direction of the mover 13. Outer magnetic poles 22, 23 arranged in
The magnetic flux introduction side to the iron piece 32 through the outer magnetic pole 2
2 and 23 are changed alternately, and as a result, the iron piece 3
2, that is, the mover 13 is reciprocated. Therefore, the mover 13 can be reciprocated with a simple structure, the manufacturing is facilitated, and the cost can be further reduced.

Further, since the set of the permanent magnet 14 and the pair of outer magnetic poles 22 and 23 is provided only on one side of the iron piece 32, the weight can be reduced as a whole.

Moreover, since the permanent magnet 14 and the pair of outer magnetic poles 22 and 23 are provided only on the outer side in the radial direction with respect to the cylindrical iron piece 32, the radius of the iron piece 32, that is, the mover 13 is reduced. Therefore, the weight of the mover 13 can be reduced.

Further, since the inner magnetic pole 19 facing the iron piece 32 on the side opposite to the permanent magnet 14 is integrally formed with the yoke 12, they are not separately manufactured or joined together. Therefore, manufacturing becomes easier.

In addition, since the mover 13 is formed by insert molding of synthetic resin having the iron piece 32 as a nest, the mover 13 including the iron piece 32 can be formed easily and lightweight.

Further, the mover 13 is provided with the ball bush 28.
Since it is supported by the yoke 12 via the
Can be accurately reciprocated.

In addition, since the yoke 12 is made of a sintered material, the cost and performance (reduction of iron loss) can be improved, and the mechanical strength can be improved. The same effect can be obtained by forming the yoke 12 with a dust core.

The base portion 30 and the cylindrical portion 31 of the mover 13 may be formed of aluminum die-cast or non-magnetic stainless steel instead of synthetic resin as long as they are non-magnetic materials. In this case, there is an advantage that rigidity can be improved. is there. However, it is more preferable to use a synthetic resin in terms of weight reduction.

As the permanent magnet 14, other than the above-mentioned ferrite magnet, it is also possible to use a rare earth material such as neodymium or samarium cobalt, or a plastic magnet, but a ferrite magnet is used. It is more preferable from the viewpoint of cost reduction.

In addition to the ball bush, the bearing of the mover 13 may be an air bearing (gas bearing), a sliding bearing, or the like. However, it is more preferable to use the ball bush 28 because the mover 13 can reciprocate more accurately.

Further, this linear actuator 11
Is generally used by incorporating a spring in the movable part or by resonating 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.

Furthermore, in order to improve the performance such as displacement characteristics, the inner magnetic pole 19 and the outer magnetic poles 22 and 23 may be chamfered or the like.

In addition to the sintered material, the inner magnetic pole 19, the outer magnetic poles 22 and 23, and the iron piece 32 may have a laminated structure of electric iron plates for reducing iron loss during high-speed operation.

Further, the outer magnetic poles 22 and 23 may be in the shape of a short cylinder having no protrusion as shown by the solid line in FIG. 4, or the protrusion 21 as shown by the broken line in FIG.
May be provided on both the inner diameter side and the outer shape side. In addition, as shown in FIG. 4, the mover 14 may not be supported on the yoke 12 by the ball bush 28 or the like.

Next, a linear actuator according to a second embodiment of the present invention will be described below with reference to FIG. The same parts as those in the first embodiment are designated by the same reference numerals, and the description thereof will be omitted.

Linear actuator 11 of the second embodiment
In place of the connecting portion 20 and the inner magnetic pole 19, the inner cylindrical portion 35 coaxial with the outer cylindrical portion 17 is integrally provided inside the yoke 12 in the radial direction. A ring-shaped coil 36 is fixed not only on the outer side but also on the inner side inside the corner portion of the boundary between the bottom plate portion 18 of the yoke 12 and the inner cylindrical portion 35 so as to be coaxial with the yoke 12.

Further, in addition to the outer side, on the inner side as well, there are a permanent magnet 37 composed of a thin plate ring-shaped ferrite magnet or the like in which both magnetic poles, that is, the N pole 37a and the S pole 37b are arranged in the axial direction, and the outer diameter side. Has a L-shaped cross section in which an axially projecting portion 38 is formed, and a pair of annular burners are arranged on both sides of the permanent magnet 37 in the axial direction so that the projecting portions 38 project in opposite directions. An inner magnetic pole (magnetic pole member) 39 and an inner magnetic pole (magnetic pole member) 40 made of a binder are provided. These permanent magnets 37
And the pair of inner magnetic poles 39 and 40 are formed by the permanent magnet 37.
In a state where both sides of the magnetic poles 37a and 37b in the arrangement direction are sandwiched by annular inner magnetic poles 39 and 40,
It is coaxially fixed to the yoke 12 by being press-fitted to the outside of the inner cylindrical portion 35 of the yoke 12.

In this fixed state, the permanent magnet 37 is the S pole 37.
b is disposed on the bottom plate portion 18 side, and one inner magnetic pole 39 is in a state of being adjacent to the coil 36 in the axial direction. Further, in this fixed state, the permanent magnet 37 and the pair of inner magnetic poles 39, 40 as a whole are
4 and a pair of outer magnetic poles 22 and 23 are arranged coaxially therewith, and the permanent magnet 37 is the outer permanent magnet 14, the inner magnetic pole 39 is the outer magnetic pole 22, and the inner magnetic pole 40 is the outer magnetic pole. 23 and the coil 36 also match the axial position and length with the outer coil 15, respectively. Then, an annular gap portion 25 is formed between the permanent magnet 37 and the pair of inner magnetic poles 39, 40 and the permanent magnet 14 and the pair of outer magnetic poles 22, 23.

Then, the bush 26 is provided on the inner peripheral side of the inner cylindrical portion 35 of the yoke 12 so that the shaft 26 can move in the axial direction.
The ball bush 28 supported by 7 is the bush 2
It is fixed coaxially at 7. Ball bush 28
The mover 13 fixed to the shaft 26 of the
4 and a pair of outer magnetic poles 22 and 23, and the permanent magnet 3
7 and a pair of inner magnetic poles 39, 40 in the annular gap 25, the iron piece 32 as a cylindrical movable magnetic pole.
Are arranged similarly to the first embodiment.

The linear actuator 11 of the second embodiment described above can also achieve the same effect as that of the first embodiment, and on top of that, the permanent magnet 14 and the pair of outer magnetic poles 22 and 23, and the permanent magnet 37. Since the pair of inner magnetic poles 39 and 40 is provided on both sides with the iron piece 32 interposed therebetween, a stronger magnetic field of the permanent magnet and a magnetomotive force due to the current can be obtained.

Next, a linear actuator according to a third embodiment of the present invention will be described below with reference to FIG. The same parts as those in the first embodiment are designated by the same reference numerals, and the description thereof will be omitted.

Linear actuator 11 of the third embodiment
In place of the connecting portion 20 and the inner magnetic pole 19, the inner cylindrical portion 44 coaxial with the outer cylindrical portion 17 is integrally provided inside the yoke 12 in the radial direction.

Then, on the inner side as well as the outer side, a permanent magnet 45 composed of a thin plate ring-shaped ferrite magnet or the like in which both magnetic poles, that is, N pole 45a and S pole 45b are arranged in the axial direction, and a cylindrical shape are provided. None, an inner magnetic pole (magnetic pole member) 46 and an inner magnetic pole (magnetic pole member) 47 made of a pair of sintered materials are provided on both sides of the permanent magnet 45 in the axial direction. The permanent magnet 45 and the pair of inner magnetic poles 46, 47 are sandwiched by the cylindrical inner magnetic poles 46, 47 on both sides in the direction in which the magnetic poles 45a, 45b of the permanent magnet 45 are arranged, and the inner cylindrical portion 44 of the yoke 12 is formed. It is coaxially fixed to the yoke 12 by being press-fitted to the outside of the.

In this fixed state, the permanent magnet 45 has the S pole 45.
b will be arranged on the side of the bottom plate portion 18. Further, in this fixed state, the permanent magnet 45 and the pair of inner magnetic poles 4 are
6, 47 are arranged coaxially with the permanent magnet 14 and the pair of outer magnetic poles 22, 23 as a whole, and the permanent magnet 45 is the permanent magnet 14 on the outer side.
The inner magnetic pole 46 and the outer magnetic pole 47 are aligned with each other in axial position and length, respectively. An annular gap 25 is formed between the permanent magnet 14 and the pair of outer magnetic poles 22 and 23, and the permanent magnet 45 and the pair of inner magnetic poles 46 and 47.

The bush 26 is provided on the inner peripheral side of the inner cylindrical portion 44 of the yoke 12 so that the shaft 26 can move in the axial direction.
The ball bush 28 supported by 7 is the bush 2
It is fixed coaxially at 7. Ball bush 28
The mover 13 fixed to the shaft 26 of the
4 and a pair of outer magnetic poles 22 and 23, and a permanent magnet 4
5 and the pair of inner magnetic poles 46, 47, in the annular gap portion 25, the iron piece 32 as a cylindrical movable magnetic pole.
Are arranged similarly to the first embodiment. In this case, a rare earth magnet is suitable as the inner permanent magnet 45.

The above-described linear actuator 11 of the third embodiment can also achieve the same effect as that of the first embodiment, and on top of that, the permanent magnet 14 and the pair of outer magnetic poles 22 and 23, and the permanent magnet 45. Since a pair of inner magnetic poles 46 and 47 are provided on both sides with the iron piece 32 interposed therebetween, a stronger magnetic field of the permanent magnet and a magnetomotive force due to the current can be obtained.

Next, a linear actuator according to a fourth embodiment of the present invention will be described below with reference to FIG. The same parts as those in the first embodiment are designated by the same reference numerals, and the description thereof will be omitted.

Linear actuator 11 of the fourth embodiment
In place of the connecting portion 20 and the inner magnetic pole 19, the inner cylindrical portion 35 coaxial with the outer cylindrical portion 17 is integrally provided inside the yoke 12 in the radial direction. Then, instead of the outer side, the ring-shaped coil 36 is attached to the inner side of the yoke 1
The yoke 12 is coaxially fixed inside the corner portion of the boundary between the bottom plate portion 18 and the inner cylindrical portion 35.

Also, instead of the outer side, the inner side
Both magnetic poles, that is, the N pole 37a and the S pole 37b are arranged in the axial direction. The permanent magnet 37 is made of a thin plate ring-shaped ferrite magnet and the like, and the protruding portion 38 that protrudes in the axial direction toward the outer diameter side.
And an inner magnetic pole (a magnetic pole member) made of a pair of annular sintered materials, each having an L-shaped cross section and formed so as to project the projecting portions 38 in opposite directions on both sides in the axial direction of the permanent magnet 37. ) 39 and an inner magnetic pole (magnetic pole member) 40. The permanent magnet 37 and the pair of inner magnetic poles 39, 40 are sandwiched between the inner magnetic poles 39, 40 on both sides of the permanent magnet 37 in the direction of the arrangement of the magnetic poles 37a, 37b of the permanent magnet 37. It is coaxially fixed to the yoke 12 by being press-fitted to the outside.

In this fixed state, the permanent magnet 37 is the S pole 37.
b is disposed on the bottom plate portion 18 side, and one inner magnetic pole 39 is in a state of being adjacent to the coil 36 in the axial direction. Then, the annular gap 25 is formed between the permanent magnet 37 and the pair of inner magnetic poles 39, 40 and the outer cylindrical portion 17.

Then, the bush 26 is provided on the inner peripheral side of the inner cylindrical portion 35 of the yoke 12 so that the shaft 26 can move in the axial direction.
The ball bush 28 supported by 7 is the bush 2
It is fixed coaxially at 7. Ball bush 28
The mover 13 fixed to the shaft 26 of the
7 and a pair of inner magnetic poles 39, 40 and outer cylindrical portion 17
An iron piece 32 as a cylindrical movable magnetic pole is arranged in the annular gap portion 25 between the same as in the first embodiment.
As a result, the permanent magnet 37 and the pair of inner magnetic poles 3
The set of 9, 40 is provided only on the inner side in the radial direction with respect to the cylindrical iron piece 32.

The above-described linear actuator 11 of the fourth embodiment can also achieve the same effect as that of the first embodiment, and the permanent magnet 37 and the pair of inner magnetic poles 39 and 40 are arranged on the iron piece 32. Since it is provided only on the inner side in the radial direction, the radii of the permanent magnet 37 and the pair of inner magnetic poles 39, 40 can be reduced, and the weight of these can be reduced, and the overall weight can be reduced.

Next, a linear actuator according to a fifth embodiment of the present invention will be described below with reference to FIGS. 8 to 11 focusing on parts different from the first embodiment. The same parts as those in the first embodiment are designated by the same reference numerals, and the description thereof will be omitted.

In the fifth embodiment, a plurality of pairs of permanent magnets 14 and a pair of outer magnetic poles 22, 23 are provided in the reciprocating direction of the mover 13, that is, the axial direction, specifically, two pairs. The outer cylindrical portion 17 of the yoke 12 and the two sets of outer magnetic poles 22 and 23 are integrally formed by sintering with a sintered material which is a common magnetic material.

However, the adjacent permanent magnets 14 have different magnetic pole directions. Specifically, in the permanent magnet 14 on the bottom plate portion 18 side, the N pole 14 a is arranged on the bottom plate portion 18 side and the S pole 14 b is arranged on the opposite side to the bottom plate portion 18, and the permanent magnet on the opposite side to the bottom plate portion 18 is arranged. In the magnet 14, the N pole 14a is arranged on the opposite side to the bottom plate portion 18 and S
The pole 14b is arranged on the bottom plate portion 18 side.

The one iron piece 32 is provided so as to face one set of the permanent magnet 14 and the pair of outer magnetic poles 22, 23, and the other iron piece 32 is the other of the permanent magnet 14 and the pair of outer magnetic poles 22, 23. Are provided facing each other.

In addition, the position between the permanent magnet 14 and each pair of outer magnetic poles 22 and 23, that is, on the side opposite to the bottom plate portion 18 of the pair of outer magnetic poles 22 and 23 on the bottom plate portion 18 side. The coil 15 is arranged between the outer magnetic pole 23 and the outer magnetic pole 22 on the bottom plate 18 side of the set of outer magnetic poles 22, 23 on the opposite side of the bottom plate 18.

Further, on the outer diameter side of the inner magnetic pole 19,
An annular groove portion 60 that is recessed by one step is formed at a position between both permanent magnets 14 in the reciprocating direction of the mover 13 and between each pair of outer magnetic poles 22 and 23. In addition, the ball bush 28 has a plurality of bushes 27, specifically, two bushes 27.

In the fifth embodiment, when an alternating current (sine wave current, rectangular wave current) is passed through the coil 16, the coil 16
When a current flows in a predetermined direction, the magnetic flux, as shown by the chain double-dashed line in FIG. The outer magnetic pole 22 on the part 18 side, the permanent magnet 14 on the opposite side of the bottom plate part 18 of the permanent magnets 14 and the bottom plate part 1
8 of the outer magnetic poles 22 and 23 on the opposite side, the outer magnetic pole 23 and the mover 13 on the opposite side to the bottom plate portion 18.
Of the iron plate 32 on the opposite side of the bottom plate portion 18 of the above, the inner magnetic pole 19 of the yoke 12, and the iron piece 3 of the mover 13 on the bottom plate portion 18 side.
2. Outer magnetic pole 23 on the opposite side to bottom plate 18 of the set of outer magnetic poles 22, 23 on the side of bottom plate 18, permanent magnet 14 on the side of bottom plate 18 of both permanent magnets 14, bottom plate 18
Out of the set of outer magnetic poles 22 and 23 on the side, the outer magnetic pole 22 on the side of the bottom plate 18 and the outer cylindrical portion 17 form a magnetic flux loop in this order.
A force is applied in the direction opposite to 8 to move in the opposite direction. On the other hand, when a current flows in the coil 16 in the direction opposite to the predetermined direction, as shown by the chain double-dashed line in FIG.
Of the pair of outer magnetic poles 22 and 23 on the side, the outer magnetic pole 23 on the opposite side to the bottom plate portion 18, the permanent magnet 14 on the bottom plate portion 18 side of both permanent magnets 14, and the set of the outer magnetic poles 22 and 23 on the bottom plate portion 18 side Outer magnetic pole 2 on the bottom plate 18 side of the
2, the iron piece 32 on the bottom plate 18 side of the mover 13, the yoke 12
Of the inner magnetic pole 19, the iron piece 32 on the opposite side of the bottom plate portion 18 of the mover 13, and the outer magnetic poles 22 and 23 on the opposite side of the bottom plate portion 18, the outer magnetic pole 2 on the bottom plate portion 18 side.
2. Out of the permanent magnets 14, the permanent magnet 14 on the opposite side to the bottom plate portion 18 and the outer magnetic pole 2 on the opposite side to the bottom plate portion 18
In the set of 2, 23, the outer magnetic pole 23 and the outer cylindrical portion 17 on the opposite side to the bottom plate portion 18 form a magnetic flux loop in this order, and as a result, the mover 13 moves to the bottom plate portion 18 side. A force is applied in a direction to move in this direction.

By alternately changing the direction of the current flow to the coil 16 due to the alternating current, the above operation is repeated and the mover 13 reciprocates in the axial direction with respect to the yoke 12.

According to the fifth embodiment, the yoke 12 is provided with a plurality of sets of the permanent magnet 14 and the outer magnetic poles 22 and 23 in the reciprocating direction of the mover 13.
Since a plurality of iron pieces 32 are provided in the mover 13 in the reciprocating direction of the mover 13, a larger thrust can be generated in the mover 13.

Further, on the outer diameter side of the inner magnetic pole 19, an annular groove portion 60 which is recessed by one step is formed at a position between both permanent magnets 14 in the reciprocating direction of the mover 13, so that the mover 13 is formed. It is possible to generate even greater thrust.

As shown in FIG. 11, the outer magnetic poles 22 and 23 are formed separately from the outer cylindrical portion 17, and the permanent magnet 1 is formed.
It may be press-fitted into the outer cylindrical portion 17 together with 4.

Further, in the fifth embodiment, a plurality of sets of the permanent magnet 14 and the pair of outer magnetic poles 22 and 23 of the first embodiment are provided in the reciprocating direction of the mover 13, and the mover 13 is provided with the iron piece 32. The case where a plurality of magnets are provided in the reciprocating direction has been described as an example. However, the permanent magnets 14, 3 of the second embodiment
7, outer magnetic poles 22 and 23 and inner magnetic pole 39,
A plurality of sets of 40 are provided in the reciprocating direction of the mover 13, and a plurality of iron pieces 32 are provided in the mover 13 in the reciprocating direction, or the pair of permanent magnets 14, 45, the outer magnetic pole 22, of the third embodiment. 23 and a plurality of pairs of inner magnetic poles 46 and 47 are provided in the reciprocating direction of the mover 13, and a plurality of iron pieces 32 are provided in the mover 13 in the reciprocating direction, and the pair of permanent magnets 37 and 37 of the fourth embodiment. Inner magnetic pole 3
It is also possible to provide a plurality of sets of 9, 40 in the reciprocating direction of the mover 13 and a plurality of iron pieces 32 in the mover 13 in the reciprocating direction.

Next, the linear actuator of the sixth embodiment of the present invention will be described below with reference to FIG. 12 focusing on the differences from the fifth embodiment. The same parts as those in the fifth embodiment are designated by the same reference numerals, and the description thereof will be omitted.

In the sixth embodiment, the outer diameter of the outer magnetic poles 22 and 23 is permanent with respect to each set of the permanent magnet 14 and the pair of outer magnetic poles 22 and 23 provided in the reciprocating direction of the mover 13. The diameter is smaller than the outer diameter of the magnet 14, and as a result, the outer magnetic pole 22 and the yoke 1
2 and the outer cylindrical portion 17 of the yoke 12, and the outer cylindrical portion 17 of the yoke 12, respectively.
An annular gap (magnetic gap) serving as a magnetic resistance means that serves as a magnetic resistance to a magnetic flux loop formed by the magnetic force of the permanent magnet 14 on the outer cylindrical portion 17 of the second magnet, the permanent magnet 14, and the pair of outer magnetic poles 22 and 23. ) 50 is formed.

According to the sixth embodiment, the gap between the outer cylindrical portion 17 of the yoke 12, the permanent magnet 14, and the pair of outer magnetic poles 22 and 23 with respect to the magnetic flux loop formed by the magnetic force of the permanent magnet 14 is large. Since 50 is a magnetic resistance, the outer magnetic poles 22,
It is possible to increase the number of magnetic fluxes guided between the 23 and the iron piece 32. Therefore, the magnetic flux generated by the permanent magnet 14 can be effectively used for moving the iron piece 32, that is, the mover 13, and the thrust can be generated in the mover 13 sufficiently and stably.

The gap 50 is defined by the outer magnetic pole 2
An air gap or a non-magnetic spacer may be used because a magnetic gap may be provided between the second and the second cylinders 23 and the outer cylindrical portion 17 of the yoke 12. If a non-magnetic spacer is interposed as a magnetic gap between the outer magnetic poles 22 and 23 and the outer cylindrical portion 17, the outer magnetic poles 22 and 23 are formed by the spacers.
Can be mechanically fixed to. This spacer can be formed of plastic, aluminum, stainless steel, copper, or the like.

[0096]

As described in detail above, the first aspect of the present invention
According to the linear actuator described above, a coil is provided in which the iron piece is provided on the mover, the permanent magnet is provided on the stator so as to face the iron piece, and the coil is provided on the stator to change the direction of current on the stator side. By moving the magnetic flux passing through the iron piece with the permanent magnet, the iron piece, 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. . At the same time, the weight of the mover does not increase even if the weight of the permanent magnet increases when trying to obtain a high magnetic flux density in order to improve the performance. Further, since the mover has no magnet, it is not necessary to magnetize the mover. Therefore, the reliability can be improved, the performance can be easily improved, and the manufacturing can be facilitated to reduce the cost.

According to the linear actuator of the second aspect of the present invention, when the current direction of the coil on the stator side alternates, both sides of the permanent magnet whose magnetic poles are arranged along the reciprocating direction of the mover. The introduction side of the magnetic flux to the iron piece via the magnetic pole member arranged at is alternately changed, and the iron piece, that is, the mover is reciprocated. Therefore,
The mover can be reciprocated with a simple structure, manufacturing is facilitated, and further cost reduction can be achieved.

According to the linear actuator of claim 3 of the present invention, the set of the permanent magnet and the pair of magnetic pole members comprises:
Since it is provided on only one side of the iron piece, the weight can be reduced as a whole.

According to the linear actuator of claim 4 of the present invention, the set of the permanent magnet and the pair of magnetic pole members comprises:
Since it is provided only on the outer side in the radial direction with respect to the iron piece, the radius of the iron piece, that is, the mover can be reduced, so that the weight of the mover can be particularly reduced.

According to the linear actuator of claim 5 of the present invention, the set of the permanent magnet and the pair of magnetic pole members comprises:
Since it is provided only on the inner side in the radial direction with respect to the iron piece, the radii of the permanent magnet and the pair of magnetic pole members can be reduced, and the weight of these can be reduced, and the overall weight can be reduced.

According to the linear actuator of claim 6 of the present invention, the set of the permanent magnet and the pair of magnetic pole members is:
Since it is provided on both sides via the iron piece, it is possible to obtain a stronger magnetomotive force due to the magnetic field and current of the permanent magnet.

According to the linear actuator of claim 7 of the present invention, since the magnetic pole member facing the iron piece on the side opposite to the permanent magnet is integrally molded with the stator, these magnetic pole members can be manufactured separately or later. It will not be joined. Therefore, manufacturing becomes easier.

According to the linear actuator of claim 8 of the present invention, since the mover is formed by insert molding of a synthetic resin containing the iron piece, the mover including the iron piece can be made easy and lightweight. Can be formed.

According to the linear actuator of the ninth aspect of the present invention, since the mover is supported by the stator via the ball bush, the mover can be accurately reciprocated.

According to the linear actuator of the tenth aspect of the present invention, the stator is provided with a plurality of permanent magnets in the reciprocating direction, and the mover is provided with a plurality of iron pieces in the reciprocating direction. Therefore, a larger thrust can be generated in the mover.

According to the linear actuator of the eleventh aspect of the present invention, since the stator is made of a sintered member, cost reduction and performance (reduction of iron loss) can be achieved, and mechanical strength can be improved.

[Brief description of drawings]

FIG. 1 is a side cross-sectional view showing a linear actuator of a first embodiment of the present invention, showing a state of magnetic flux in a state where no current flows in a coil by a chain double-dashed line.

FIG. 2 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 in a state where a current flows in one direction in a coil by a two-dot chain line.

FIG. 3 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 in a state where current flows in the coil in the opposite direction by a two-dot chain line.

FIG. 4 is a side sectional view showing a modified example of the linear actuator of the first embodiment of the present invention.

FIG. 5 is a side sectional view showing a linear actuator according to a second embodiment of the present invention, and shows a state of magnetic flux in a state where current does not flow in the coil by a chain double-dashed line.

FIG. 6 is a side sectional view showing a linear actuator according to a third embodiment of the present invention, and shows a state of magnetic flux in a state where no current flows through the coil by a chain double-dashed line.

FIG. 7 is a side sectional view showing a linear actuator according to a fourth embodiment of the present invention.

FIG. 8 is a side sectional view showing a linear actuator according to a fifth embodiment of the present invention, in which the state of magnetic flux when no current is flowing in the coil is indicated by a chain double-dashed line.

FIG. 9 is a side sectional view showing a linear actuator according to a fifth embodiment of the present invention, showing a state of magnetic flux in a state where current flows in one direction in a coil by a chain double-dashed line.

FIG. 10 is a side sectional view showing a linear actuator according to a fifth embodiment of the present invention, and shows a state of magnetic flux in a state where current flows in the coil in the opposite direction by a two-dot chain line.

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

FIG. 12 is a side sectional view showing a linear actuator according to a sixth embodiment of the present invention, and shows a state of magnetic flux in a state where no current flows through the coil by a chain double-dashed line.

[Explanation of symbols]

11 linear actuator 12 yoke (stator) 13 mover 14, 37, 45 permanent magnets 14a, 37a, 45a N pole (magnetic pole) 14b, 37b, 45b S pole (magnetic pole) 15 coil 19, 39, 40, 46, 47 Inner magnetic pole (magnetic member) 22,23 Outer magnetic pole (magnetic member) 28 Ball bush 32 Iron piece

Claims (11)

[Claims] 1. A stator, a mover provided with an iron piece so as to be capable of reciprocating with respect to the stator, a permanent magnet provided on the stator in a state of facing the iron piece, and the stator. A linear actuator having a coil provided in the. 2. The permanent magnet is provided on the stator with magnetic poles arranged in the reciprocating direction, and a pair of magnetic pole members are provided on both sides of the permanent magnet in the reciprocating direction. The linear actuator according to claim 1, wherein the linear actuator is provided. 3. The linear actuator according to claim 2, wherein the set of the permanent magnet and the pair of magnetic pole members is provided only on one side of the iron piece. 4. The iron piece has a cylindrical shape, and the set of the permanent magnet and the pair of magnetic pole members is provided only outside in the radial direction with respect to the iron piece. Linear actuator. 5. The iron piece has a cylindrical shape, and the set of the permanent magnet and the pair of magnetic pole members is provided only on the inner side in the radial direction with respect to the iron piece. Linear actuator. 6. The linear actuator according to claim 2, wherein the set of the permanent magnet and the pair of magnetic pole members is provided on both sides via the iron piece. 7. The linear member according to claim 1, wherein the stator is integrally formed with a magnetic pole member facing the iron piece on a side opposite to the permanent magnet. Actuator. 8. The linear actuator according to claim 1, wherein the mover is formed by insert molding of synthetic resin having the iron piece as a nest. 9. The linear actuator according to claim 1, wherein the mover is supported by the stator via a ball bush. 10. The stator is provided with a plurality of the permanent magnets in the reciprocating direction, and the mover is provided with a plurality of the iron pieces in the reciprocating direction. The linear actuator according to any one of claims 1 to 9. 11. The linear actuator according to claim 1, wherein the stator is made of a sintered member.