JP2003189578A - Movable magnet type electromagnetic actuator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain an electromagnetic actuator in which an increase in thickness as a whole is suppressed while a sufficient thrust is assured and a size can be reduced. <P>SOLUTION: The magnet movable type electromagnetic actuator comprises an inner yoke 10a for forming an inside pole teeth 11A, an outer yoke 10b for forming an outside pole teeth 12A, a yoke 10A having a space 13A between the yokes 10a and 10b, an annular exciting coil 14 housed in the space 13A and surrounding the periphery of the yoke 10a, and a permanent magnet 15 magnetized at N-poles and S-poles in the radial direction and arranged so as to be freely displacable in the axial direction of the yoke 10A. <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 movable magnet type electromagnetic actuator.

[0002]

2. Description of the Related Art Conventionally, as a reciprocating device for electromagnetically moving an object, an electromagnetic wave is applied to a movable iron core connected to an output shaft by applying a voltage to an exciting coil and by its magnetic force. Solenoid (electromagnetic actuator)
Is known. Although this electromagnetic solenoid has a simple structure, it has a problem that it is difficult to improve the electrical response because the iron core is included inside the exciting coil. It is necessary to apply a large voltage to the coil.

In order to solve this problem, the inventor of the present invention has proposed an electromagnetic actuator having an improved electric response by using a permanent magnet in place of the movable iron core (Japanese Patent Application No. 2000-217304). . In this electromagnetic actuator, the response is enhanced by utilizing the magnetism of the permanent magnet and the electromagnetic field generated from the exciting coil when energized, without applying a large voltage at the time of starting unlike the electromagnetic solenoid. In such an electromagnetic actuator, if it is necessary to secure a stronger thrust while securing a high electrical response, increase the number of turns of the exciting coil or increase the permanent magnet to increase the magnetic force. However, this may be a major obstacle in the case of this type in which further miniaturization is required, since the actuator as a whole may become thick.

[0004]

SUMMARY OF THE INVENTION The problem to be solved by the present invention is to provide an electromagnetic actuator capable of suppressing the increase in the thickness as a whole and achieving a miniaturization while securing a sufficient thrust. Especially.

[0005]

In order to solve the above-mentioned problems, a movable magnet type electromagnetic actuator of the present invention comprises a columnar inner yoke portion forming inner pole teeth and an inner yoke portion outside the inner yoke portion. At least one yoke having an outer yoke portion that surrounds at least a part of the outer periphery of the outer yoke and forms outer pole teeth, and a space portion between these yoke portions; and is housed in the space portion of the yoke. An annular exciting coil surrounding the inner yoke portion; having a shape and a size that can be arranged between the inner yoke and the outer yoke, and having an N pole and an S pole magnetized in the radial direction. A permanent magnet disposed between the outer pole tooth and the inner pole tooth so as to be displaceable in the axial direction of the yoke.

The electromagnetic actuator having the above structure is
The yoke is composed of a cylindrical inner yoke portion forming inner pole teeth, a cylindrical outer yoke portion concentrically located around the inner yoke portion to form outer pole teeth, and a space between these yoke portions. And a ring-shaped space located at, and the excitation coil is disposed in the space,
Since the permanent magnet magnetized in the radial direction is arranged concentrically between the outer pole teeth and the inner pole teeth of the yoke so as to be displaceable in the axial direction of the yoke, By changing the permanent magnet, the permanent magnet can be efficiently driven in its axial direction, and since the exciting coil is positioned in the moving direction of the permanent magnet, the number of turns of the exciting coil is increased to increase the outer diameter. Or, even if the outer diameter of the permanent magnet is increased to some extent, the thickness of the entire actuator becomes larger than that of the conventional one in which the exciting coil is arranged at a position facing the outer peripheral surface of the permanent magnet. Therefore, it is possible to reduce the size of the electromagnetic actuator as a whole while securing a sufficient thrust.

In the present invention, the outer yoke portion and the permanent magnet may each be in the shape of a cylinder having a circular or polygonal cross section. In this case, the electromagnetic actuator is provided with the outer yoke portion. A cover attached to the tip of the casing to form a casing together with the yoke, a magnet chamber formed in the casing, a magnet holder movably disposed in the magnet chamber and holding the permanent magnet, It is arranged in the center of the magnet chamber so as to be movable back and forth in the axial direction of the casing, the base end side is connected to the magnet holder, and the tip side penetrates the cover and is output to the outside of the casing. And a shaft of the same. Also, a pair of the above-mentioned yokes, a cylindrical sleeve that forms a casing by connecting these yokes in a direction in which their inner and outer pole teeth face each other, and a magnet chamber formed inside the casing, A magnet holder movably arranged in the magnet chamber for holding the permanent magnet, and a magnet holder arranged at the center of the magnet chamber so as to be movable back and forth in the axial direction of the casing.
It is also possible to have an output shaft that is coupled to the magnet holder and that extends through the pair of yokes and is led out of the casing.

Further, according to the present invention, the outer yoke portion and the permanent magnet may each have an incomplete cylindrical shape in which a part of the side surface is opened. In this case, the outer yoke portion is formed. A linear guide mechanism including a rail and a slide member that moves on the rail may be installed in the open portion of the side surface of the, and the permanent magnet may be attached to the slide member.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows in principle the structure of a first magnet movable electromagnetic actuator according to the present invention. The first electromagnetic actuator 1A has inner pole teeth 1
A cylindrical inner yoke portion 10a forming 1 and a cylindrical outer yoke portion 10b that is integrally connected to the inner yoke portion 10a and is concentrically located around the inner yoke portion 10a to form the outer pole teeth 12. Both of these yoke parts 10
a yoke 10 having an annular space 13 located between a and 10b, and an annular exciting coil 14 housed in the space 13 of the yoke 10 and surrounding the inner yoke 10a. Outer pole teeth 1 in the yoke 10
2 and the yoke 1 concentrically at a position between the inner pole tooth 2 and the inner pole tooth 11.
It is arranged so that it can be displaced in the direction of the axis of 0, and the N pole and S
Cylindrical permanent magnet 15 whose poles are magnetized in the radial direction
And have.

The inner yoke portion 10a and the outer yoke portion 10b are longer than the length (width) of the exciting coil 14 in the axial direction, and even when the exciting coil 14 is housed in the space 13, it projects in the distal direction. There is. Then, the protruding portions are the inner pole teeth 11 and the outer pole teeth 1 respectively.
Make up 2. These inner and outer pole teeth 11, 12
The gap between them is formed larger than the wall thickness of the permanent magnet 15. Therefore, when the permanent magnet 15 approaches the moving end on the side of the exciting coil 14, the permanent magnet 15 causes the inner and outer pole teeth 1 in the space portion 13 of the yoke 10 to move.
The outer peripheral surface of the inner pole tooth 11 and the inner peripheral surface of the permanent magnet 15, and the inner peripheral surface of the outer pole tooth 12 and the outer peripheral surface of the permanent magnet. The surfaces will face each other.

In the first electromagnetic actuator 1A, as shown in FIG. 1, the permanent magnet 15 is magnetized in the radial direction so that the outer peripheral surface side thereof has an S pole and the inner peripheral surface side thereof has an N pole. . In this state, the exciting coil 14
When energized in the direction indicated by the symbol in FIG. 1, the inner pole tooth 11 of the yoke 10 becomes the N pole and the outer pole tooth 1 by the direction of the current.
2 becomes the south pole. Therefore, the N pole generated in the inner pole tooth 11 and the N pole on the inner peripheral surface side of the permanent magnet 15 facing the N pole.
A repulsive force acts between the pole and the S pole generated on the outer pole teeth 12 and the S pole on the outer peripheral surface side of the permanent magnet 15 facing the pole. Then, a large thrust is generated in the permanent magnet 15 in a direction (direction of an arrow in FIG. 1) to escape from the space between the inner and outer pole teeth 11 and 12, whereby the permanent magnet 15 is driven.

When the exciting coil 14 is energized in the reverse direction, the N and S magnetic poles generated on the inner and outer pole teeth 11 and 12 of the yoke 10 have an opposite relationship to the above-mentioned case, so that the permanent magnet is used. The direction of the thrust generated in 15 also becomes the opposite direction (right in FIG. 1), and the permanent magnet 15 moves in the direction of entering the space between the inner and outer pole teeth 11, 12.

When the exciting coil 14 is not energized, the permanent magnet 15 becomes the S pole from the N pole of the permanent magnet 15 through the magnetic path from the inner pole tooth 11 to the outer pole tooth 12 of the yoke 10. Due to the action of the reaching magnetic flux, the magnetic flux is basically attracted to the yoke 10 side and stops at the moving end on the yoke 10 side.

The first electromagnetic actuator 1A having the above-mentioned structure is provided with the inner yoke portion 10a of the yoke 10.
Space portion 13 located between the outer yoke portion 10b and the outer yoke portion 10b
An exciting coil 14 is provided inside, and a permanent magnet 15 is arranged concentrically at a position between the outer pole tooth 12 and the inner pole tooth 11 of the yoke 10 so as to be displaceable in the axial direction of the yoke 10. Since the exciting coil 14 is positioned on the moving direction of the permanent magnet by providing the exciting coil 14, the number of turns of the exciting coil 14 is increased to increase the outer diameter,
Alternatively, even if the outer diameter of the permanent magnet 15 is increased to some extent,
It is possible to suppress an increase in the thickness of the entire actuator as compared with the conventional one in which the exciting coil is arranged at a position facing the outer peripheral surface of the permanent magnet.
It is possible to reduce the size of the entire electromagnetic actuator while securing a sufficient thrust. Further, since the inner yoke portion 10a and the outer yoke portion 10b forming the inner and outer pole teeth 11 and 12 are integrally formed as the yoke 10, the number of parts as a whole can be reduced.

In the first electromagnetic actuator 1A, since the magnetic path of the yoke 10 as a whole is formed between the inner and outer pole teeth 11 and 12, the both pole teeth 11 and 12 are formed.
The thrust force and magnetic attraction force of the permanent magnet 15 may be adjusted by adjusting the length and thickness of 12 or the magnetic characteristics of the yoke 10 itself.

Further, the first electromagnetic actuator 1A
In the above, the inner yoke portion 10a and the outer yoke portion 10b of the yoke 10 have a cylindrical shape and a cylindrical shape, respectively, and the magnet 15 has a cylindrical shape. However, as shown in FIG.
In the yoke 10A, the inner yoke portion 10Aa may have a quadrangular prism shape, the outer yoke portion 10Ab may have a quadrangular tubular shape, and the magnet 15A may have a quadrangular tubular shape. The inner yoke portion 10Aa does not necessarily have to be a quadrangular prism shape, and may have an arbitrary polygonal column shape, and further, the cylindrical outer yoke portion 10Aa.
A prismatic shape may be used for b, on the other hand, the outer yoke portion 10Aa may not have a rectangular cross-section, but may have a polygonal cross-section. The inner yoke portion 10Aa may be of a tubular shape having various polygonal cross sections. In this case, the magnet 15
The shape of is adapted to the shape of either of the yoke portions 10Aa and 10Ab.

FIG. 3 shows in principle the structure of a second movable magnet type electromagnetic actuator according to the present invention. The second electromagnetic actuator 1B includes an inner yoke portion 20a forming inner pole teeth 21, an outer yoke portion 20b integrally connected to the inner yoke portion 20a to form outer pole teeth 22, and both yoke portions 20a, 20b. It has one yoke 20 having a space 23, an exciting coil 24 housed in the space 23, and a permanent magnet 25, and has the above-mentioned first electromagnetic actuator 1A and an inner pole. The tooth 21 has a different configuration.

That is, the inner yoke portion 20a is formed to have substantially the same length as the axial direction of the exciting coil 24, and when the exciting coil 24 is housed in the space portion 23, the outer pole portion 20a is formed. Unlike the tooth 22, it does not protrude from the exciting coil 24, and the tip of the inner yoke portion 20a constitutes the inner pole tooth 21. Therefore, when the permanent magnet 25 approaches the vicinity of the moving end on the side of the exciting coil 24,
A part of the permanent magnet 25 is accommodated in the hollow formed by the outer pole teeth 22 of the outer yoke portion 20b, and one of the inner peripheral surface of the outer pole teeth 22 and the outer peripheral surface of the permanent magnet 25 becomes one. The parts will face each other. The second electromagnetic actuator 1B is substantially the same as the above-described first electromagnetic actuator 1A except for the inner yoke portion 20a and the inner pole teeth 21, and the description thereof will be omitted.

The second electromagnetic actuator 1B having the above structure can obtain basically the same actions and effects as those of the first electromagnetic actuator 1A. In this case, since the inner pole teeth 21 do not protrude from the exciting coil 24,
Although the thrust force is smaller than that of the actuator 1A, the structure of the yoke 20 is relatively simple and the molding is easy, and
The degree of freedom of the support structure of the permanent magnet 25 can be increased.

In the second electromagnetic actuator 1B, the inner yoke portion 20a and the outer yoke portion 20b of the yoke 20 have a cylindrical shape and a cylindrical shape, respectively, and the magnet 25 has a cylindrical shape. To make the magnet 25 adapt to the shape of either of the yoke portions 20a and 20b by making it into a square pole or other prismatic shape, or the outer yoke portion 20b having a tubular shape with various polygonal cross-sections, Same as the case.

4 and 5 show in principle the structure of a third magnet movable electromagnetic actuator according to the present invention. The third electromagnetic actuator 1C includes a square columnar inner yoke portion 30a forming inner pole teeth 31, an outer yoke portion 30b forming outer pole teeth 32, and a space portion 33 between the two yoke portions 30a and 30b. A single yoke 30, a magnetizing coil 34 housed in the space 33 and surrounding the inner yoke portion 30a, and a permanent magnet 35 magnetized in the radial direction.

The outer yoke portion 30b is formed in a tubular shape having an incomplete quadrangular cross section (a U-shaped cross section) with a part of the side surface opened. Then, at the opening, the rail 36
A linear guide mechanism having a slide member 37 that moves on the rail 36 is installed. In the third electromagnetic actuator 1C, in the linear guide mechanism, a concave groove portion 37a that slidably rides on the rail 36 is provided in the central portion on the lower surface side of the slide member 37, and the rail 36 is provided.
Grooves 38, 38 are formed on the opposite surfaces of both side surfaces of the groove and the groove walls of the concave groove portion 37a of the slide member 37, respectively.
A steel ball 39 is rotatably disposed in the shaft 38.

Similar to the outer yoke portion, the magnet 35 is formed in a tubular shape having an incomplete quadrangular cross section (a U-shaped cross section) with a part of the side surface opened, and the open portion thereof is the slide member 37. Is fixed to the upper surface side of.

The third electromagnetic actuator 1C having the above-described structure can basically obtain the same operation and effect as the first electromagnetic actuator 1A, but since the magnet 35 is guided by the linear guide mechanism, When the exciting coil 34 is energized, smoother movement is possible.

In the third electromagnetic actuator 1C, the inner yoke portion 30a has a quadrangular prism shape, and the outer yoke portion 30b and the magnet 35 have a cylindrical shape with an incomplete quadrangular cross section with a part of the side surface open. The inner yoke portion may have a columnar shape or another prismatic shape, and the outer yoke portion 30b and the magnet 35 have a cylindrical shape with various incomplete polygonal cross sections or circular cross sections as long as part of the side surface is open. Good.

FIG. 6 shows one of the embodiments embodying the first electromagnetic actuator 1A shown in FIG. The fourth electromagnetic actuator 1D includes one yoke 40, an exciting coil 44 formed by winding a winding 44b around a bobbin 44a, and one end of the yoke 40 to mount a casing together with the yoke 40. A cover 46 made of a non-magnetic material, a cylindrical permanent magnet 45 disposed in the casing and having N and S poles magnetized in a radial direction, and a magnet to which the permanent magnet 45 is attached. A holder 47 and a shaft 48 for output, the tip side of which is led out of the casing, are provided.

The yoke 40 has a cylindrical inner yoke portion 40a forming inner pole teeth 41 and outer pole teeth 42 located concentrically around the inner yoke portion 40a.
And an outer yoke portion 40b that forms the above, and a base portion 40c that connects the two yoke portions 40a and 40b at their base end sides and that has a function of an end cover of the casing. An annular space 43 is formed between the yokes 40a and 40b, and the exciting coil 44 is housed in the space 43. Then, the inner yoke portion 40a and the outer yoke portion 40
In b, the portions protruding from the exciting coil 44 in the space 43 are referred to as inner pole teeth 41 and outer pole teeth 42, respectively.

The cover 46 has, at one end side thereof, a hollow portion forming a magnet chamber 49 described later, and the open end side of the hollow portion is fitted to the tip end side of the outer peripheral surface of the outer pole tooth 42. is doing. Therefore, the casing is
6 and the outer yoke portion 40b and the base portion 40c of the yoke 40. Further, the cover 46 is provided with a through hole 46a for leading the tip end side of the shaft 48 from the hollow portion side to the outside of the casing.

The permanent magnet 45 is provided in the casing.
A magnet chamber 49 for movably accommodating a magnet holder 47 to which is attached is formed, and the shaft 48 is arranged at the center of the magnet chamber 49 so as to be movable back and forth in the axial direction of the casing. There is. The magnet holder 47 is
The thrust generated from the permanent magnet 45 is transmitted to the shaft 48 to drive it, and is fixed to the base end side of the shaft 48 so as to be displaced together. Further, the magnet holder 47 is formed in a concave shape so as to cover the tip side of the inner yoke portion 40a, and when the permanent magnet 45 is close to the moving end on the yoke 40 side, It is configured so as not to contact the outer peripheral surface. The permanent magnet 45 is fitted on the outer peripheral surface side of the magnet holder 47.

The fourth electromagnetic actuator 1D having the above structure is used for connecting the tip end side of the shaft 48 to a target object and conveying the target object. With the shaft 48 at the right end as shown in FIG.
4 is energized and a current is applied to the inner and outer pole teeth 41, 42 in a direction in which magnetic poles opposite to the inner and outer magnetic poles of the permanent magnet 45 are generated. A repulsive force is generated between the magnetic pole and the magnetic pole of the permanent magnet 45,
Since a thrust force is generated in the permanent magnet 45 in a direction to escape from the space between the pole teeth 41 and 42, the shaft 48 advances to the left end.

When a current in the opposite direction is passed through the exciting coil with the permanent magnet 45 at the forward end, the bipolar teeth 4
Since magnetic poles opposite to those in the above case are generated in 1, 42,
The permanent magnet 45 is attracted to the yoke 40 side by the mutual magnetic attraction force between the bipolar teeth 41 and 42, whereby the shaft 48 and the permanent magnet 45 quickly retreat to the return end (right end). Depending on the weight of the shaft 48, the permanent magnet 45, the magnet holder 47, the magnetic force of the permanent magnet 45, and the like, even if the excitation coil 44 is de-energized, the permanent magnet 45 may be released.
The return operation of the shaft 48 may be performed only by the magnetic force of.

The above fourth electromagnetic actuator 1D
, The permanent magnet 4 whose magnetic poles are magnetized in the radial direction
5, the shaft 48 and the magnet holder 47 are used.
Since the lateral load acting on the movable part including the permanent magnet 45 and the permanent magnet 45 is small, the bearing 46b supporting the shaft 48 provided in the through hole 46a of the cover 46 may have a simple structure, which reduces the cost and reduces the lateral It can be expected to improve the durability due to the load.

FIG. 7 shows an embodiment in which the first electromagnetic actuator 1A shown in FIG. 1 is embodied and which is different from the above-mentioned fourth electromagnetic actuator. Although the fourth actuator 1D has a configuration including one yoke, the fifth electromagnetic actuator 1E described below is
It has two yokes.

That is, this fifth electromagnetic actuator 1E
Includes a pair of yokes 50A and 50B,
Exciting coils 54A and 54B formed by winding windings 64A and 64B around A and 63B, and the pair of yokes 50A and 50B with their inner and outer pole teeth 51A,
Cylindrical sleeve 56 that forms a part of the casing and that connects 51B, 52A, and 52B in a direction in which they face each other.
A cylindrical permanent magnet 55 disposed in the casing and having N and S poles magnetized in the radial direction, a magnet holder 57 for holding the permanent magnet 55, and a front and rear direction in the axial direction of the casing. An output shaft 58 penetrating the pair of yokes 50A and 50B, which is movably arranged.
And have.

The pair of yokes 50A and 50B are basically the same in shape, and both have inner pole teeth 51A and
A cylindrical inner yoke portion 50Aa forming 51B,
50Ba, outer yoke portions 50Ab and 50Bb that form outer pole teeth 52A and 52B concentrically around the inner yoke portions 50Aa and 50Ba, outer portions 50Aa and 50Ba, and inner yoke portions 50Ab,
It has integrally the base parts 50Ac and 50Bc having the function of the cover of the casing, which connects with 50Bb at the base end side. Each of the yokes 50A, 50B has an annular space 53A, 53B formed at a position between the two yokes, and the exciting coils 54A, 54B are housed in the space 53A, 53B. There is. Of the outer portions 50Aa, 50Ba and the inner yoke portions 50Ab, 50Bb, the space portions 53A, 53
B is the inner pole teeth 51A, 51B and the outer pole teeth 52A, the portions protruding from the exciting coils 54A, 54B.
52B. In addition, each of the above-mentioned yokes 50A and 50B
The inner yoke parts 50Aa, 5A
Through hole 6 that penetrates 0Ba and the base portions 50Ac, 50Bc
1A and 61B are provided through which the shaft 58 is inserted. Further, bearings 62A and 62B for supporting the shaft 58 slidably in the longitudinal direction are attached to the through holes 61A and 61B on the side of the base portions 60A and 60B.

The sleeve 56 has openings at the left and right ends thereof which are 50Ab and 50B of the yokes 50A and 50B.
It is fitted on the tip side of b. Therefore, the casing includes the sleeve 56 and the pair of yokes 50A and 50B.
Outer yoke portions 50Ab, 50Bb and base portion 50A
c, 50 Bc.

The permanent magnet 55 is provided in the casing.
A magnet chamber 59 for movably accommodating a magnet holder 57 attached thereto is formed, and the shaft 58 is arranged in the center of the magnet chamber 59 so as to be movable back and forth in the axial direction of the casing. There is. The magnet holder 57 is formed in such a shape as to cover both tip ends of the inner yoke portions 50Aa and 50Ba, is fixed near the middle of the shaft 58 so as to be displaceable integrally with the shaft 58, and is a permanent magnet. When 55 is close to the moving end on the side of each of the yokes 50A and 50B, it is configured so as to cover the outer peripheral surface on the tip side of the inner yoke portions 50Aa and 50Ba on the moving end side without contact. The permanent magnet 55
Is fixed to the center of the outer peripheral surface side of the magnet holder 57 immovably.

The fifth electromagnetic actuator 1E having the above structure is used for transporting the target object by connecting the tip end side (the left end in this embodiment) of the shaft 58 to the target object. As shown in FIG. 7, in the state where the permanent magnet 55 is on the moving end on the side of the yoke 50B located on the right side and the shaft 58 is on the return end side, the yoke 50 located on the left side is located.
When the exciting coil 54A attached to A is energized and a current is applied to the inner and outer pole teeth 51A and 52A in a direction in which a magnetic pole attracting the inner and outer magnetic poles of the permanent magnet 55 is generated, An attractive force is generated between the magnetic poles of the teeth 51A and 52A and the magnetic pole of the permanent magnet 55, while
The excitation coil 54B attached to the yoke 50B located on the right side is energized to generate inner and outer pole teeth 51B and 52
When a current is applied to B in a direction in which magnetic poles opposite to the magnetic poles on the inner peripheral side and the outer peripheral side of the permanent magnet 55 are generated, the bipolar teeth 51
A repulsive force is generated between the magnetic poles generated in B and 52B and the magnetic pole of the permanent magnet 55. As a result, a thrust is generated in the direction in which the permanent magnet 55 moves from the right side yoke 50B side to the left side yoke 50A side, and the shaft 58 advances to the left side end.

When a current in the opposite direction to the above-described case is applied to each of the exciting coils 54A and 54B while the permanent magnet 55 is at the forward end, the pole teeth of each yoke are opposite to the case described above. Since the magnetic poles are generated, the permanent magnet 55 is attracted to the right side yoke 50B side, which causes the shaft 5
8 and the permanent magnet 55 quickly retreat to the return end (right end). Note that, depending on the weight of the shaft 58, the permanent magnet 55, the magnet holder 57, the magnetic force of the permanent magnet, and the like, when the energization of the exciting coils 54A and 54B is released, the permanent magnet 5 is released.
The magnetic force of 5 may move the shaft 58 toward the closest yoke side at the current position.

In the fifth electromagnetic actuator 1E having the above structure, the exciting coil is specially provided as compared with the third electromagnetic actuator 1E described above in which the yoke and the exciting coil are provided on only one side of the casing. It is easy to obtain a large thrust without increasing the number of turns of the coil or increasing the magnetic force of the permanent magnet, and the electrical response is good.

In the above-mentioned fifth electromagnetic actuator 1E, the pair of yokes 50A and 50B having the same shape are used, but the lengths and wall thicknesses of the inner and outer pole teeth are different, and the yokes of the pair of yokes are different. The magnetic attraction force or repulsive force with the permanent magnet 55 may be adjusted between them.

In the above-mentioned fourth and fifth electromagnetic actuators 1D and 1E, the inner yoke portion is made into a square pole or other prismatic shape, the outer yoke portion is made into a tubular shape having various polygonal cross sections, and magnets are used. It is the same as in the case of the first electromagnetic actuator 1A described above that it is desirable to adapt the shape of any one of the yoke portions.

[0043]

According to the electromagnetic actuator of the present invention described in detail above, the yoke is composed of a cylindrical inner yoke portion forming inner pole teeth, and an outer yoke located concentrically around the inner yoke portion. An outer yoke portion forming pole teeth and an annular space portion located between the two yoke portions are provided, an exciting coil is disposed in the space portion, and a permanent magnet is provided on the outer pole teeth of the yoke. Since the exciting coil is positioned between the inner pole tooth and the inner pole tooth so as to be concentrically displaceable in the axial direction of the yoke, the exciting coil is positioned in the moving direction of the permanent magnet. Even if the outer diameter is increased by increasing the number of turns, or the outer diameter of the permanent magnet is increased to some extent, it is possible to prevent the overall thickness of the actuator from increasing. While ensuring also, it is possible to achieve miniaturization of the entire electromagnetic actuator.

[Brief description of drawings]

FIG. 1 is a sectional view showing in principle the configuration of a first movable magnet type electromagnetic actuator according to the present invention.

FIG. 2 is a cross-sectional view showing an embodiment different from FIG.

FIG. 3 is a sectional view showing in principle the configuration of a second movable magnet type electromagnetic actuator according to the present invention.

FIG. 4 is a transverse cross-sectional view showing in principle the configuration of a third movable magnet type electromagnetic actuator according to the present invention.

5 is a cross-sectional view taken along the line AA of FIG.

6 is a cross-sectional view showing a fourth electromagnetic actuator which is an embodiment in which the electromagnetic actuator of FIG. 1 is embodied.

FIG. 7 is a sectional view showing a fifth electromagnetic actuator which is an embodiment different from FIG.

[Explanation of symbols]

1A, 1B, 1C, 1D, 1E Electromagnetic actuator 10, 20, 30, 40, 50A, 50B Yoke 10a, 20a, 30a, 40a, 50Aa, 50Ba
Inner yoke parts 10b, 20b, 30b, 40a, 50Ab, 50Bb
Outer yoke parts 11, 21, 31, 41, 51A, 51B Inner pole teeth 12, 22, 32, 42, 52A, 52B Outer pole teeth 13, 23, 33, 43, 53A, 53B Space portions 14, 24, 34, 44, 54A, 54B Excitation coil 15, 25, 35, 45, 55 Magnet 36 Rail 37 Slide member 46 Case 47, 57 Magnet holder 48, 58 Shaft 49, 59 Magnet chamber 56 Sleeve

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Claims (6)

[Claims] 1. A column-shaped inner yoke portion forming inner pole teeth, and an outer portion formed outside the inner yoke portion so as to surround at least a part of the outer circumference of the inner yoke portion to form outer pole teeth. At least one yoke having a yoke portion and a space portion between the yoke portions; an annular exciting coil housed in the space portion of the yoke and surrounding the inner yoke portion; the inner yoke and the outer yoke. Has a shape and a size that can be arranged between the N pole and the S pole, and the N pole and the S pole are magnetized in the radial direction,
A magnet movable electromagnetic actuator comprising: a permanent magnet disposed between the outer pole tooth and the inner pole tooth so as to be displaceable in the axial direction of the yoke. 2. The electromagnetic actuator according to claim 1, wherein the outer yoke portion and the permanent magnet are respectively
A cylinder with a circular or polygonal cross section. 3. The electromagnetic actuator according to claim 1, wherein the outer yoke portion and the permanent magnet are respectively
Incomplete cylindrical shape with a part of the side surface open. 4. The electromagnetic actuator according to claim 2, wherein the electromagnetic actuator is attached to a tip of the outer yoke portion to form a casing together with the yoke, and a magnet chamber formed in the casing. And a magnet holder movably arranged in the magnet chamber for holding the permanent magnet, and a magnet holder arranged in the center of the magnet chamber so as to be movable back and forth in the axial direction of the casing. An output shaft that is connected to the holder and has an output shaft that extends through the cover at its tip side and is led out of the casing. 5. The electromagnetic actuator according to claim 2, wherein a pair of the yokes and a cylindrical sleeve that forms a casing by connecting the yokes so that their inner and outer pole teeth face each other. A magnet chamber formed inside the casing, a magnet holder movably arranged in the magnet chamber for holding the permanent magnet, and a central portion of the magnet chamber that is movable back and forth in the axial direction of the casing. And an output shaft which is connected to the magnet holder and is led out of the casing through the pair of yokes. 6. The electromagnetic actuator according to claim 3, wherein a linear guide mechanism including a rail and a slide member that moves on the rail is installed at an opening portion of a side surface of the outer yoke portion, and the slide member is provided on the slide member. The one to which the above-mentioned permanent magnet is attached.