JP2003250256A - Linear actuator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a linear actuator by which reliability can be improved and performance can be easily improved. <P>SOLUTION: The actuator includes a stator 12; an iron piece 32; a mover 13 provided on the stator 12 in a reciprocative manner; a pair of permanent magnets 14, 15 which face the iron piece 32 in a mutually adjoined state in the reciprocating direction, of which the magnetic poles line up intersecting at right angles in the reciprocating direction, and which are provided at the side of the stator 12 with the line of each other's magnetic poles reversed; and a coil 16 provided on the stator 12, wherein the iron piece 32 or the mover 13 is reciprocated by moving a magnetic flux passing through the iron piece 32, with the coil 16 and the permanent magnets 14, 15 in which a direction of a current of the side of the stator 12 changes. <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 and a mover having an iron piece that is provided so as to reciprocate with respect to the stator; and a stator that opposes the iron piece while being adjacent to each other in the reciprocating direction and is orthogonal to the reciprocating direction. And a pair of permanent magnets provided on the stator in a state where the magnetic poles are arranged side by side and the arrangement of the magnetic poles is reversed, and a coil provided on the stator.

Thus, the iron piece is provided on the mover, the coil is provided on the stator, and the magnetic poles are arranged adjacent to each other in the reciprocating direction of the mover so as to face the iron piece and be orthogonal to the reciprocating direction. Since a pair of permanent magnets are arranged on the stator in a state where the magnetic poles are arranged in reverse, when the direction of the current of the coil on the stator side changes alternately, the magnetic flux in the pair of permanent magnets changes. Will pass through alternately,
The side that guides the magnetic flux with respect to the iron piece is alternately changed by the pair of permanent magnets, and 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.

A linear actuator according to a second aspect of the present invention is the linear actuator according to the first aspect, characterized in that the pair of permanent magnets are provided only on one side of the iron piece.

As described above, since the pair of permanent magnets are provided only on one side of the iron piece, the weight can be reduced as a whole.

According to a third aspect of the present invention, in the linear actuator according to the first or second aspect, the stator is integrally formed with a magnetic pole member facing the iron piece on the opposite side of the permanent magnet. It is characterized by

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

A linear actuator according to a fourth aspect of the present invention relates to the linear actuator according to the first aspect, characterized in that the pair of permanent magnets is provided on both sides via the iron piece.

As described above, since the pair of permanent magnets is provided on both sides through 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 a fifth aspect of the present invention, in the linear actuator according to any one of the first to fourth aspects, the iron piece has a cylindrical shape, and the coil is radially outward of the iron piece. It is characterized by being provided.

As described above, since the coil is provided outside the iron piece in the radial direction, 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 a sixth aspect of the present invention, in the linear actuator according to any one of the first to fourth aspects, the iron piece has a cylindrical shape, and the coil is radially inward of the iron piece. It is provided, The linear actuator as described in any one of Claim 1 thru | or 4 characterized by the above-mentioned.

As described above, since the coil is provided inside the iron piece in the radial direction, the weight of the coil can be reduced and the overall weight can be reduced.

A linear actuator according to a seventh aspect of the present invention is the linear actuator according to any one of the first to sixth aspects, wherein 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 lightly.

The linear actuator according to claim 8 of the present invention is the linear actuator according to any one of claims 1 to 7, characterized in that the mover is supported by the stator via a ball bush. I am trying.

Thus, since the mover is supported by the stator via the ball bush, the mover can be accurately reciprocated.

A linear actuator according to a ninth aspect of the present invention is the linear actuator according to any one of the first to eighth aspects, wherein a plurality of sets of the pair of permanent magnets are provided in the stator in the reciprocating direction. The movable element is provided with a plurality of the iron pieces in the reciprocating direction.

As described above, the stator is provided with a plurality of pairs of permanent magnets in the reciprocating direction, and the mover is provided with a plurality of iron pieces in the reciprocating direction.
It is possible to generate a larger thrust on the mover.

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 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.

[0028]

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.

The linear actuator 11 of the first embodiment
Is a yoke (stator) 12, a mover 13 reciprocally provided on the yoke 12, a pair of permanent magnets 14 and 15 fixed to the yoke 12, and a coil 16 fixed to the yoke 12. Is equipped with.

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 16 has a ring shape and is coaxially fixed to the inside of a corner of the boundary between the bottom plate portion 18 and the outer cylindrical portion 17 of the yoke 12.

The permanent magnets 14 and 15 are cylindrical ferrite ring magnets having the same diameter and the same length.
They are arranged so as to be adjacent to each other in the axial direction. 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. Specifically, one permanent magnet 14 has an N pole 14a arranged on the outer diameter side and an S pole 14b arranged on the inner diameter side, and the other permanent magnet 15 has an N pole 15a on the inner diameter side and an S pole 15b on the inner diameter side. It is located on the outer diameter side. Outer magnetic poles made of an annular sintered material having an L-shaped cross section, on the outer sides of these permanent magnets 14 and 15 in the radial direction, formed with a projecting portion 21 that projects in a substantially cylindrical shape in the axial direction on the inner diameter side ( The magnetic pole member) 22 has permanent magnets 14, 1 on its inner diameter side.
5 is provided to hold. The outer magnetic pole 22 holding the permanent magnets 14 and 15 is press-fitted inside the outer cylindrical portion 17 of the yoke 12 on the outer diameter side thereof, so that the permanent magnets 14 and 15 and the outer magnetic pole 22 are It is fixed coaxially with the yoke 12.

In this fixed state, the permanent magnets 14 and 15 are
The permanent magnet 14 is arranged at an intermediate position in the radial direction of the yoke 12, one permanent magnet 14 is arranged on the bottom plate portion 18 side, the other permanent magnet 15 is arranged on the opposite side to the bottom plate portion 18, and the outer magnetic pole 22 is coiled. 16 are adjacent to each other in the axial direction. In this fixed state, the permanent magnet 14,
The reference numeral 15 is arranged coaxially with the cylindrical inner magnetic pole 19 of the yoke 12 as a whole, and is also arranged so that the cylindrical inner magnetic pole 19 of the yoke 12 as a whole is aligned with the axial position and length. Therefore, an annular gap portion 25 is formed between the inner magnetic pole piece 19 and the inner magnetic pole piece 19.

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 pair of movers 13 is provided. The permanent magnets 14 and 15 are movable elements 1 with respect to each other.
The three magnetic poles are arranged adjacent to each other in the direction of reciprocal movement, facing the outer diameter side of the iron piece 32 and perpendicular to the direction of the reciprocal movement, and are fixed to the yoke 12 with their magnetic poles reversed. Will be done. The outer magnetic pole 22 is provided on the outer diameter side of the mover 13, and the yoke 12 is integrally formed with the inner magnetic pole 19 facing the iron piece 32 on the side opposite to the permanent magnets 14 and 15. become. Further, the pair of permanent magnets 14 and 15 are provided only on one side of the iron piece 32, and specifically, only on the outer side in the radial direction with respect to the cylindrical iron piece 32. Further, the coil 16 has a cylindrical iron piece 32 and a pair of permanent magnets 14,
It is provided radially outside of 15.

In the linear actuator 11 having the above structure, when an alternating current (sinusoidal wave current, rectangular wave current) is passed through the coil 16, a current flows in a predetermined direction through the coil 16, which is indicated by a chain double-dashed line in FIG. As described above, the magnetic flux is guided from the S pole 15b to the N pole 15a side by the permanent magnet 15, so that the outer cylindrical portion 17 of the yoke 12, the outer magnetic pole 22,
The permanent magnet 15, the iron piece 32 of the mover 13, the inner magnetic pole 19 of the yoke 12, the connecting portion 20, the bottom plate portion 18, the outer cylindrical portion 1
7 to form a magnetic flux loop, and as a result,
The mover 13 moves in this direction when a force F is applied to the mover 13 toward the permanent magnet 15. On the other hand, in a state where 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.
By being guided to the N pole 14a side from b, the yoke 12
The outer cylindrical portion 17, the bottom plate portion 18, the connecting portion 20, the inner magnetic pole 19, the iron piece 32 of the mover 13, the permanent magnet 14, the outer magnetic pole 22, and the outer cylindrical portion 17 form a magnetic flux loop in this order. As a result, the mover 13 has the opposite permanent magnet 1
The force F is applied in the direction of moving to the 4 side 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 linear actuator 11 of the first embodiment described above, the mover 13 is provided with the iron piece 32, the coil 16 is provided on the yoke 12, and the mover 13 is adjacent in the reciprocating direction. In a state of facing the iron piece 32 and arranging the magnetic poles orthogonal to the direction of reciprocal movement, and arranging the magnetic poles in the opposite direction, the pair of permanent magnets 14,
Since 15 is provided in the yoke 12, when the direction of the current of the coil 16 on the yoke 12 side is alternately changed, the magnetic flux alternately passes through the pair of permanent magnets 14 and 15, and the magnetic flux is transmitted to the iron piece 32. The pair of permanent magnets 1 on the side that guides
Alternately, the iron pieces 32, that is, the mover 13 is reciprocated. As a result, the mover 13 can be reciprocated with a simple structure.

As described above, since the coil 16 is provided on the yoke 12 rather than on the side of the mover 13, it is not necessary to feed power to the side of the mover 13, and the moving mover 13 disconnects the feed line to the coil 16. It will not be caused. Therefore, it is possible to improve reliability for continuous operation and the like.

Further, since the permanent magnets 14 and 15 are also provided on the yoke 12 rather than on the side of the mover 13, when the high magnetic flux density is obtained in order to improve the performance, the permanent magnet 1
Even if the weights of 4 and 15 increase, the weight of the mover 13 does not increase. Therefore, performance improvement (thrust increase)
Can be easily achieved. 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.

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 the accuracy of the coaxial concentricity of the linear actuator 11 is improved. You can As a result, the bearing or ball bush 28
It is possible to reduce the burden on the engine and extend its life.

Further, since the pair of permanent magnets 14 and 15 are provided only on one side of the iron piece 32, the weight can be reduced as a whole.

Moreover, since the coil 16 is provided outside the cylindrical iron piece 32 and the pair of permanent magnets 14 and 15 in the radial direction, the radius of the iron piece 32, that is, the mover 13, can be reduced, and therefore, In particular, 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 magnets 14 and 15 is integrally formed with the yoke 12, they are not separately manufactured or joined later. . 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 easily and lightweight formed.

Further, the mover 13 is a 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, it is possible to reduce costs, improve performance (reduce iron loss), and improve mechanical strength. 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.

Further, as the permanent magnets 14 and 15, other than the above-mentioned ferrite magnets, it is also possible to use rare earth materials such as neodymium and samarium cobalt, or plastic magnets, but ferrite magnets are used. 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.

Further, in order to improve the performance such as the displacement characteristic, the inner magnetic pole 19 and the outer magnetic pole 22 may be chamfered or the like.

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

Further, 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.

Further, in addition to the outer side, permanent magnets 36 and 37 made of cylindrical ferrite ring magnets having the same diameter and the same length are provided side by side on the inner side so as to be adjacent to each other in the axial direction. ing. Here, the permanent magnets 36 and 37 are also of radial anisotropy in which magnetic poles are arranged in a direction orthogonal to the axial direction, and the arrangement of the magnetic poles is reversed. Specifically, one permanent magnet 36 is
The N pole 36a is arranged on the outer diameter side and the S pole 36b is arranged on the inner diameter side. In the other permanent magnet 37, the N pole 37a is arranged on the inner diameter side.
The pole 37b is arranged on the outer diameter side. These permanent magnets 3
6, 37 are arranged in the axial direction and are press-fitted to the outside of the inner cylindrical portion 35 of the yoke 12 so that the yoke 12
It is fixed coaxially to.

In this fixed state, one permanent magnet 36 is arranged on the bottom plate portion 18 side, and the other permanent magnet 37 is arranged on the opposite side to the bottom plate portion 18. Further, in this fixed state, the permanent magnets 36 and 37 are arranged inside the permanent magnets 14 and 15 as a whole so as to be coaxial therewith, and moreover, the permanent magnet 36 is the outer side permanent magnet 14 and the permanent magnet 37. Aligns with the outer permanent magnet 15 in axial position and length, respectively. Then, the pair of permanent magnets 14 and 15
The annular gap 25 is formed between the pair of permanent magnets 36 and 37.

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
In the annular gap 25 between the magnets 4, 15 and the permanent magnets 36, 37, the iron piece 32 as a cylindrical movable magnetic pole is first
It is arranged similarly to the 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, a set of a pair of permanent magnets 14 and 15 and a pair of permanent magnets 36 and 37. Are provided on both sides via the iron piece 32, so that a stronger magnetomotive force due to the magnetic field and current of the permanent magnet 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.

Also, instead of the outer side, the inner side
Permanent magnets 45 and 46 made of cylindrical ferrite ring magnets having the same coaxial diameter and length are arranged side by side so as to be adjacent to each other in the axial direction. Here, the permanent magnets 45 and 46 are also 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 one permanent magnet 45, the N pole 45a is arranged on the inner diameter side and the S pole 45b is arranged on the outer diameter side, and in the other permanent magnet 46, the N pole 46a is arranged on the outer diameter side. Are arranged on the inner diameter side. These permanent magnets 4
5, 46 are press-fitted to the outside of the inner cylindrical portion 44 of the yoke 12 while being aligned in the axial direction.
It is fixed coaxially to.

In this fixed state, one permanent magnet 45 is arranged on the bottom plate portion 18 side, and the other permanent magnet 46 is arranged on the opposite side to the bottom plate portion 18. In this fixed state, the permanent magnets 45 and 46 are arranged inside the outer magnetic pole 22 where the permanent magnet is not provided as a whole so as to be coaxial therewith, and moreover, as a whole, they are positioned axially with the outer magnetic pole 22. And the length is adjusted. Then, the outer magnetic pole 22 not provided with the permanent magnet and the pair of permanent magnets 4
An annular gap 25 is formed between the gaps 5 and 46.

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 second embodiment has an iron piece 32 as a cylindrical movable magnetic pole in the annular gap portion 25 between the outer magnetic pole 22 and the permanent magnets 45 and 46 as in the first embodiment. It is arranged. In this case, the permanent magnet 4
Rare earth magnets are suitable as 5, 46.

The linear actuator 11 of the third embodiment described above can also achieve the same effects as those of the first embodiment, and on top of that, the amount of magnets used can be reduced.

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.

The coil 16 has a ring shape, and is fixed coaxially with the yoke 12 inside the corner of the boundary between the bottom plate portion 18 of the yoke 12 and the inner cylindrical portion 35.

Also, instead of the outer side, the inner side
Permanent magnets 36 and 37, which are cylindrical ferrite ring magnets having the same coaxial diameter and the same length, are arranged side by side so as to be adjacent to each other in the axial direction. Here, the permanent magnets 36 and 37 are also of radial anisotropy in which magnetic poles are arranged in a direction orthogonal to the axial direction, and the arrangement of the magnetic poles is reversed. Specifically, one permanent magnet 36 has an N pole 36a arranged on the outer diameter side and an S pole 36b arranged on the inner diameter side, and the other permanent magnet 37 has an N pole 37a on the inner diameter side and an S pole 37b on the inner diameter side. It is located on the outer diameter side. These permanent magnets 3
Inner magnetic poles (magnetic pole members) made of a ring-shaped sintered material having an L-shaped cross section in which radially outer portions 6 and 37 are formed with projecting portions 51 that project toward the outer diameter side in the axial direction in a substantially cylindrical shape. ) 50 is provided so as to hold the permanent magnets 36, 37 on the outer diameter side thereof. Thus, the permanent magnets 36, 3
The inner magnetic pole 50 holding 7 is pressed into the inner cylindrical portion 35 of the yoke 12 on the inner diameter side thereof, so that the permanent magnets 36 and 37 and the inner magnetic pole 50 are pressed.
Are fixed coaxially with the yoke 12.

In this fixed state, one permanent magnet 36 is arranged on the bottom plate portion 18 side, and the other permanent magnet 37 is arranged on the opposite side to the bottom plate portion 18. Then, the pair of permanent magnets 36, 3
An annular gap portion 25 is formed between the outer cylindrical portion 7 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
Annular gap 25 between 6, 37 and outer cylinder 17
Further, the iron piece 32 as a cylindrical movable magnetic pole is arranged in the same manner as in the first embodiment. At this time, the coil 16 is provided radially inward of the cylindrical iron piece 32 and the permanent magnets 36, 37.

The linear actuator 11 of the fourth embodiment described above can also achieve the same effect as that of the first embodiment, and on top of that, the coil 16 is more radial than the cylindrical iron piece 32 and the permanent magnets 36, 37. Since it is provided inside, the weight of the coil 16 can be reduced, and the overall weight can be reduced.

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

Linear actuator 11 of the fifth embodiment
On the outer side in addition to the inner side of the yoke 12,
Permanent magnets 14 and 15 composed of cylindrical ferrite ring magnets having the same coaxial diameter and length are arranged side by side so as to be adjacent to each other in the axial direction. Here, the permanent magnets 14 and 15 are also 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, one permanent magnet 14 has an N pole 14a arranged on the outer diameter side and an S pole 14b arranged on the inner diameter side, and the other permanent magnet 15 has an N pole 15a on the inner diameter side and an S pole 15b on the inner diameter side. It is located on the outer diameter side. These permanent magnets 1
4, 15 are press-fitted inside the outer cylindrical portion 17 of the yoke 12 in a state where they are arranged in the axial direction.
It is fixed coaxially to.

In this fixed state, one permanent magnet 14 is arranged on the bottom plate portion 18 side, and the other permanent magnet 15 is arranged on the opposite side to the bottom plate portion 18. Further, in this fixed state, the permanent magnets 14 and 15 are arranged on the outer sides of the permanent magnets 36 and 37 as a whole so as to be coaxial with the permanent magnets 36 and 37. Moreover, the permanent magnet 14 has the inner magnet 36 and the permanent magnet 15 on the inner side. Aligns with the inner permanent magnet 37 in the axial position and length. Then, the pair of permanent magnets 14 and 15
The annular gap 25 is formed between the pair of permanent magnets 36 and 37.

Then, the shaft 2 of the ball bush 28
The mover 13 fixed to 6 has permanent magnets 14 and 15,
In the annular gap portion 25 between the permanent magnets 36 and 37,
The iron piece 32 as a cylindrical movable magnetic pole is arranged in the same manner as in the fourth embodiment.

Also in the linear actuator 11 of the fifth embodiment described above, since the coil 16 is provided inside the cylindrical iron piece 32 and the permanent magnets 36, 37 in the radial direction, the weight of the coil 16 can be reduced, and as a whole. Since the pair of permanent magnets 14 and 15 and the pair of permanent magnets 36 and 37 are provided on both sides via the iron piece 32, the permanent magnet 14 is made stronger. The magnetomotive force due to the magnetic field and current of the magnet can be obtained.

Next, a linear actuator according to a sixth embodiment of the present invention will be described below with reference to FIGS. 9 to 11 focusing on the differences 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 sixth embodiment, the outer magnetic pole 2
Two or more, specifically two, 2 are provided in the reciprocating direction of the mover 13, that is, in the axial direction, and the outer cylindrical portion 17 of the yoke 14 and the two outer magnetic poles 22 are a common magnetic material. It is integrally formed by sintering with a sintered material.

Here, the two outer magnetic poles 22 are each formed with a protrusion 21 on the side facing each other, and the coil 16 is arranged between these two outer magnetic poles 22. The two outer magnetic poles 22 are provided with the above-mentioned pair of permanent magnets 14 and 15, respectively. That is, a plurality of pairs of permanent magnets 14 and 15 are provided in the reciprocating direction of the mover 13, specifically, two pairs.

The permanent magnets 14 and 15 paired with each other.
The magnetic poles of each pair are reversed, and the pairs of the permanent magnets 14 and 15 are also reversed. Specifically, the permanent magnets 14, 1 on the bottom plate 18 side
In the group of No. 5, the permanent magnets 14 on the bottom plate portion 18 side are arranged such that the N pole 14a is arranged on the outer diameter side and the S pole 14b is arranged on the inner diameter side, and the permanent magnet 15 on the opposite side to the bottom plate portion 18 is the N pole. 1
5a is arranged on the inner diameter side and the S pole 15b is arranged on the outer diameter side.
Regarding the set of permanent magnets 14 and 15 on the side opposite to the bottom plate portion 18, the permanent magnet 14 on the bottom plate portion 18 side is the S pole 14
b is arranged on the outer diameter side, the N pole 14a is arranged on the inner diameter side, and in the permanent magnet 15 on the opposite side to the bottom plate portion 18, the S pole 15b is arranged on the inner diameter side and the N pole 15a is arranged on the outer diameter side. .

In accordance with this, the movable element 13 is also provided with a plurality of iron pieces 32, specifically, two iron pieces 32 in the reciprocating direction. That is, one iron piece 32 is provided so as to face one set of permanent magnets 14 and 15, and the other iron piece 32 is provided so as to face the other set of permanent magnets 14 and 15.

Further, on the outer diameter side of the inner magnetic pole 19,
Permanent magnets 14, 15 in the reciprocating direction of the mover 13
The annular groove portion 60 that is recessed one step at a position between each pair of
Are formed. In addition, the ball bush 28 has a plurality of bushes 27, specifically, two bushes 27.

In the sixth embodiment, when an alternating current (sine wave current, rectangular wave current) is passed through the coil 16, the coil 16
In the state where a current flows in a predetermined direction, the magnetic flux is generated by the S pole 14 in both permanent magnets 14 as shown by the two-dot chain line in FIG.
By being guided to the N pole 14a side from b, the yoke 12
Outer cylindrical portion 17, outer magnetic pole 22 opposite to the bottom plate portion 18, permanent magnet 14 opposite to the bottom plate portion 18 of both permanent magnets 14, and iron piece 32 opposite to the bottom plate portion 18 of the mover 13. , The inner magnetic pole 19 of the yoke 12, the mover 1
3, an iron piece 32 on the bottom plate portion 18 side, a permanent magnet 14 on the bottom plate portion 18 side of both permanent magnets 14, an outer magnetic pole 22 on the bottom plate portion 18 side, and an outer cylindrical portion 17 form a magnetic flux loop in this order. As a result, the mover 13 has the permanent magnets 14, 15
In the arrangement, a force is applied in the direction of movement to the permanent magnet 14 side, that is, the bottom plate portion 18 to move in this direction. on the other hand,
When a current flows in the coil 16 in a direction opposite to the predetermined direction, the yoke 12 is guided from the S pole 15b to the N pole 15a by both permanent magnets 15 as shown by the chain double-dashed line in FIG. Of the outer cylindrical portion 17, the outer magnetic pole 22 on the bottom plate 18 side, the permanent magnet 15 on the bottom plate 18 side of both permanent magnets 15, the iron piece 32 on the bottom plate 18 side of the mover 13, the inner magnetic pole 19 of the yoke 12, Bottom plate portion 18 of the child 13
On the other hand, a magnetic flux loop is formed in the order of the iron piece 32 on the opposite side, the permanent magnet 15 on the opposite side of the bottom plate portion 18 of the two permanent magnets 15, the outer magnetic pole 22 on the opposite side of the bottom plate portion 18, and the outer cylindrical portion 17. As a result, the mover 13 is moved in this direction by applying a force in the direction in which the permanent magnets 14 and 15 are arranged in the direction of moving to the side opposite to the permanent magnet 15 side, that is, the bottom plate portion 18.

By alternately changing the direction of the current flow to the coil 16 by 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 sixth embodiment as described above, the yoke 12 is provided with a plurality of pairs of permanent magnets 14 and 15 in the reciprocating direction of the mover 13, and the mover 13 has an iron piece 32. Are provided 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 one step is formed at a position between each pair of the permanent magnets 14 and 15 in the reciprocating direction of the mover 13. Therefore, a larger thrust can be generated in the mover 13.

Here, in the sixth embodiment, a plurality of sets of the pair of permanent magnets 14 and 15 and the outer magnetic poles 22 of the first embodiment are provided in the reciprocating direction of the mover 13, and the mover 13 has an iron piece 32. The description has been given by taking the case of providing a plurality of reciprocating motions as an example, but the pair of permanent magnets 1 of the second embodiment.
4, 15, a pair of permanent magnets 36, 37 and an outer magnetic pole 22 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. A plurality of pairs of the permanent magnets 45 and 46 and the outer magnetic poles 22 in the form described above 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. A pair of permanent magnets 3
A plurality of sets of 6, 37 and the inner magnetic pole 50 are provided in the reciprocating direction of the mover 13, and the mover 13 is provided with the iron piece 3
2 are provided in the reciprocating direction, or a plurality of pairs of the permanent magnets 14, 15 and the pair of permanent magnets 36, 37 and the inner magnetic pole 50 of the fifth embodiment are provided in the reciprocating direction of the mover 13. Of course, a plurality of iron pieces 32 may be provided on the mover 13 in the reciprocating direction.

[0094]

As described in detail above, the first aspect of the present invention
According to the described linear actuator, the mover is provided with the iron piece, the coil is provided on the stator, and further, the coil is opposed to the iron piece in the state of being adjacent in the reciprocating direction of the mover and orthogonal to the reciprocating direction. Since the pair of permanent magnets are arranged on the stator side in a state where the magnetic poles are arranged side by side and the arrangement of the magnetic poles is reversed, if the direction of the coil current on the stator side alternates, The magnetic flux alternately passes, and the side of the iron piece that guides the magnetic flux is alternately changed by the pair of permanent magnets, which causes the iron piece, that is, the mover to reciprocate. 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, since the pair of permanent magnets are provided only on one side of the iron piece, the weight can be reduced as a whole.

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

According to the linear actuator of the fourth aspect of the present invention, since the pair of permanent magnets is provided on both sides through the iron piece, the magnetomotive force due to the magnetic field and the current of the stronger permanent magnet is increased. Obtainable.

According to the linear actuator of the fifth aspect of the present invention, since the coil is provided on the outer side in the radial direction of the iron piece, the radius of the iron piece, that is, the mover can be made small, and, in particular, the mover is thus provided. The weight can be reduced.

According to the linear actuator of the sixth aspect of the present invention, since the coil is provided inside the iron piece in the radial direction, the weight of the coil can be reduced and the overall weight can be reduced.

According to the linear actuator of claim 7 of the present invention, since the mover is formed by insert molding of synthetic resin having the iron piece as a nest, the mover including the iron piece can be made easy and lightweight. Can be formed.

According to the linear actuator of claim 8 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 claim 9 of the present invention, the stator is provided with a plurality of pairs of permanent magnets in the reciprocating direction, and the mover is provided with the iron piece. Since a plurality is provided in the direction, a larger thrust can be generated in the mover.

According to the linear actuator of the tenth 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.

FIG. 9 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.

FIG. 10 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 current flows in one direction in a coil by a chain double-dashed line.

FIG. 11 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 current flows in the coil in the opposite direction by a two-dot chain line.

[Explanation of symbols]

11 Linear actuator 12 yoke (stator) 13 mover 14, 15, 36, 37 Permanent magnets 14a, 15a, 36a, 37a N pole (magnetic pole) 14b, 15b, 36b, 37b S pole (magnetic pole) 16 coils 19 Inner magnetic pole (magnetic member) 22 Outer magnetic pole (magnetic member) 28 ball bush 32 iron pieces

Claims (10)

[Claims] 1. A stator, a mover having an iron piece and capable of reciprocating with respect to the stator, facing the iron piece and adjoining each other in the state of being adjacent to each other in the reciprocating direction. A linear actuator including a pair of permanent magnets provided on the stator in a state where the magnetic poles are arranged orthogonally to each other and the arrangement of the magnetic poles is reversed, and a coil provided on the stator. 2. The linear actuator according to claim 1, wherein the pair of permanent magnets are provided only on one side of the iron piece. 3. The linear actuator according to claim 1, wherein the stator is integrally formed with a magnetic pole member facing the iron piece on the opposite side of the permanent magnet. 4. The pair of permanent magnets is provided on both sides with the iron piece interposed therebetween.
The described linear actuator. 5. The linear actuator according to claim 1, wherein the iron piece has a cylindrical shape, and the coil is provided radially outside the iron piece. 6. The linear actuator according to claim 1, wherein the iron piece has a cylindrical shape, and the coil is provided radially inward of the iron piece. 7. 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. 8. The linear actuator according to claim 1, wherein the mover is supported by the stator via a ball bush. 9. The stator is provided with a plurality of sets of the pair of 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 8, characterized in that: 10. The linear actuator according to claim 1, wherein the stator is made of a sintered member.