JP3215335B2 - Linear electromagnetic microactuator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a linear electromagnetic micro-actuator which is a linear motor driven linearly by an electromagnetic force and which conveys, for example, parts of a micromachine of about several mm.

[0002]

2. Description of the Related Art FIG. 6 shows a principle of operation of a conventionally used hybrid linear pulse motor (hereinafter, linear pulse motor is abbreviated as LPM). In FIG. 6, the mover 1 is composed of a permanent magnet 15, a magnetic pole A around which the coil a is wound, and a magnetic pole B around which the coil b is wound, which are coupled by the permanent magnet 15. First magnetic pole
There is an eleventh and second magnetic pole 12, and a magnetic pole B has a third magnetic pole 13 and a fourth magnetic pole 14. The four magnetic poles 11 to 14 form mover teeth. The direction of winding of the coil a around the first magnetic pole 11 is such that the direction of the current is negative so that when the direction of the current is positive (plus), the magnetic flux of the first magnetic pole 11 is in the same direction as the magnetic flux of the permanent magnet. In the case of (minus), the coil is wound so that the magnetic flux of the permanent magnet is canceled to be zero and the coil a is wound around the second magnetic pole 12 by the coil a wound around the first magnetic pole 11. When the direction of the current is positive, the magnetic flux of the permanent magnet is canceled and the magnetic flux is reduced to zero. The winding of the coil b around the third magnetic pole 13 is such that when the direction of the current is positive, the magnetic flux of the permanent magnet is negated and the magnetic flux becomes zero.
The winding of the coil b is wound in the opposite direction to the winding of the coil b around the third magnetic pole 13, so that when the direction of the current is negative, the magnetic flux of the permanent magnet is canceled and the magnetic flux becomes zero. It is wound.

On the other hand, the stator 2 has stator teeth 21 for forming magnetic flux circuits with the mover teeth. The relative positional relationship between the mover teeth and the stator teeth 21 is as shown in FIG. It is. FIG. 7 is a diagram showing a relative positional relationship between the mover teeth and the stator teeth 21 (corresponding mode in FIG. 7) and a state of energizing the coil. The driving operation is performed by repeating the modes shown in FIGS. 6A to 6D by one pitch (P in FIG. 6) of the stator teeth.

[0004] This will be described in more detail with reference to FIGS.
FIG. 6 shows a stable state in each mode.
In the mode shown in FIG. 6A, a positive current is flowing through the coil a, the magnetic flux density of the first magnetic pole 11 is high, and the magnetic flux density of the second magnetic pole 12 is zero. In FIG. 6 (a), the first magnetic pole 11 is located on the second stator tooth from the left of the stator 2. At this time, the third magnetic pole 13 of the magnetic pole B
The fourth magnetic pole 14 is located at a position where the magnetic flux is equally divided. Next, when the mode of FIG. 6A is switched to the mode of FIG. 6B, that is, when the current of the a coil is cut off and a current in the positive direction is supplied to the b coil, the magnetic flux density of the fourth magnetic pole 14 is increased. Becomes higher, the magnetic flux density of the third magnetic pole 13 becomes zero, and the fourth magnetic pole 14
Moves onto the nearest stator tooth, and becomes the state shown in FIG. 6B, and moves to the right by a quarter pitch. Subsequently, FIG.
When the mode is switched to the mode (c), that is, when the current of the coil b is cut off and a current in the negative direction is supplied to the coil a, the magnetic flux density of the second magnetic pole 12 increases, and the second magnetic pole 12 It moves onto the stator teeth, and the state shown in FIG. Further, FIG.
When the mode is switched to the mode (d), that is, when the current of the coil a is cut off and the current in the negative direction is supplied to the coil b, the magnetic flux density of the third magnetic pole 13 increases, and the third magnetic pole 13 is It moves onto the stator teeth, and the state shown in FIG. Next, when the mode is switched to the mode of FIG. 6A again, that is, when the current of the b coil is cut off and a current in the positive direction is supplied to the a coil,
When the magnetic flux density of the first magnetic pole 11 increases, the first magnetic pole 11 moves on the nearest stator tooth, and in FIG. It is in a state of moving one pitch to the right. In this way, by repeating the mode of FIG. 6A from the mode of FIG. 6A, the mover 1 moves on the stator 2 from left to right.

[0005] To move in the opposite direction, the mode switching may be reversed. In addition to the hybrid type, the LPM includes a permanent magnet type LPM using a movable element as a permanent magnet, but the basic operation principle is the same. Typically,
The LPM is an actuator whose teeth face each other on the gap surface between the mover 1 and the stator 2 and is a direct drive synchronous motor, and thus has the following features.

(1) Open loop control is possible. (2) The speed is proportional to the frequency applied to the coil. (3) Move by the distance of the product of the given number of pulses and the step pitch.

[0007]

When the LPM having the above-described operation principle and features is miniaturized and used as a microactuator, the following problems occur. (1) It is difficult to form teeth, especially with high precision. (2) Since a strong magnetic attraction force is generated between the mover teeth and the stator teeth in the vertical direction, a mechanism that supports the mover and the stator, for example, a rail is provided on the stator side, It is necessary to attach wheels to the sides and use linear bearings. Without the support mechanism, the stator and the mover come into close contact with each other due to the suction force, and the mover cannot be moved.

(3) Since a support mechanism is required, only one-dimensional linear drive can be performed. The present invention solves the above-described problems, does not require machining of the tooth shape, does not generate a strong vertical suction force between the mover and the stator, and therefore has a special support. It is an object to provide a linear electromagnetic microactuator that can move a mover two-dimensionally without requiring a mechanism.

[0009]

According to the present invention, a plurality of planar coils arranged one-dimensionally or two-dimensionally and an insulator provided on the surface thereof are provided. A linear electromagnetic microactuator comprising a stator made of layers and a mover made of a magnetic material, wherein the mover does not have a support mechanism, and does not excite a planar coil immediately below the center of the mover. The movable element is moved on the insulator by one-phase excitation of one or a plurality of planar coils located on the side of moving the movable element with respect to the planar coil.

In this case, since the planar coil immediately below the mover is not excited, no strong vertical attraction is generated between the mover and the stator. On the other hand, since the planar coil in the direction in which the mover is moved is excited, the leading end in the moving direction of the mover made of a magnetic material is attracted to the magnetic pole formed on the surface of the excited stator planar coil. Since the thrust for moving the mover is mainly used, and the suction force for sucking the mover toward the stator is small, the mover can be easily moved. In addition, when the shape of the planar coil and the mover is square or circular, the mover can be moved two-dimensionally.

It is effective that the movable element made of a magnetic material has a boat-like shape with a flat bottom surface and an open end. By doing so, the thrust for moving the mover is increased and the ripple of the thrust is reduced as compared with the case where the mover is simply a plate, a box, or a block. Further, when the mover is a permanent magnet, the thrust for moving the mover increases. However, the suction force to the stator side also increases.

Furthermore, it is effective to use a low friction material for the insulator layer or to provide a layer made of a low friction material on the surface of the insulator layer. In this way, even if the same suction force acts, the frictional force generated when the mover moves on the insulator layer of the stator can be reduced.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A linear electromagnetic microactuator according to the present invention comprises a stator comprising a plurality of planar coils arranged one-dimensionally or two-dimensionally and an insulator layer provided on the surface thereof; It is composed of a mover made of a magnetic material or a permanent magnet, and the exciting coil does not flow through the planar coil directly below the mover, but the exciting coil flows through the exciting coil to move the planar coil. The suction force between the mover and the mover is mainly used as the thrust of the mover,
It is based on reducing the suction force to the stator side.

FIG. 1 is a perspective view showing an outline of a linear electromagnetic microactuator according to the present invention. The linear electromagnetic microactuator shown in FIG. 1 is provided on a plurality of substantially square planar coils 41, such as thin-film coils, which are arranged two-dimensionally in a plane, and on a planar coil (not shown). Stator 4 made of insulating layer
And an approximately square iron of the same size as the planar coil 41, which is disposed on the planar coil (3) 44 of the stator 4;
A movable element (magnetic element movable element in the figure) 3 made of a magnetic material such as permalloy or silicon steel is used.

When moving the mover 3 in the direction A,
Electric power is supplied to the planar coil (1) 42 immediately adjacent to the moving direction side of the mover to excite it to form a magnetic pole. The mover 3 is attracted by the magnetic pole and moves on the insulator layer toward the plane coil (1) 42. In this case, since a current is not supplied to the planar coil (3) 44 immediately below the mover 3, a strong suction force for attracting the mover 3 to the stator 4 does not work, so that a large force that hinders the movement of the mover 3 is obtained. No frictional force occurs. The mover 3 is a planar coil (1) 42
When the plane coil (1) 42 is reached, the energization of the plane coil (1) 42 is stopped, and the energization is performed by energizing the plane coil (2) 43 to form a magnetic pole having the same polarity as that of the plane coil (1) 42. The child 3 moves to the plane coil (2) 43 side. By repeating this operation, the mover 3 can be moved to a predetermined position. The movement in the direction A has been described above, but the movement in the directions B, C, and D can be similarly performed.

In FIG. 1, the planar coil 41 and the mover 3
Has been described as having the same size, but the mover 3 may be larger than the plane coil 41. When the mover 3 is enlarged, the suction force for sucking the mover 3 toward the stator 4 can be further reduced. In order to move the mover 3 two-dimensionally, the shape of the mover 3 is desirably a square or a circle. This is not the case when moving one-dimensionally.

Incidentally, as the mover, a permanent magnet can be used in addition to the above-mentioned magnetic material. In this case, it is necessary to match the excitation polarity of the plane coil 41 to the direction in which the plane coil 41 attracts the permanent magnet. Examples will be described below. [First Embodiment] FIG. 2 shows that the size of the magnetic movable element 3 having a rectangular side cross section in the moving direction is three times the size of the planar coil 41, and the movable element 3 has a moving-direction-side tip (see FIG. 2). Then, the top end of the mover, hereinafter abbreviated as the top end)
(1) Magnetic flux distribution, thrust characteristics and attractive force characteristics when an exciting current is passed through 42, (a) is a magnetic flux distribution diagram, (b)
Is a characteristic diagram showing a thrust for moving the mover 3 (hereinafter, a thrust for moving the mover is abbreviated as a thrust),
(c) is a characteristic diagram showing the thrust when the exciting planar coil is sequentially switched in accordance with the movement of the mover.
(E) shows a suction force corresponding to (c), which shows a suction force (hereinafter, the suction force for sucking the mover 3 toward the stator). It is a characteristic diagram.

The horizontal axis in (b) to (e) indicates the position of the tip 31 of the mover 3, and the solid lines in (b) and (d) indicate when the exciting current flows through the planar coil (1) 42. The dotted line corresponds to the case where an exciting current is applied to the planar coil (2) 43. (a) corresponds to the vicinity of the right end of the solid line in (b) and (d), and corresponds to the bottom of the valley in (c) and (e).

In FIG. 2A, the direction of the exciting current is shown in the direction in which the upper surface becomes the S pole, but exactly the same result can be obtained by flowing in the opposite direction. The thrust characteristic shown in FIG. 2 (b) shows that when the planar coil (1) 42 is excited, the tip 31 of the mover is located at the center of the planar coil (1) 42 where the magnetic flux is concentrated. When reaching, it shows the maximum value, decreases almost symmetrically before and after that, and at the boundary with the adjacent planar coil, it does not decrease to zero due to the existence of leakage magnetic flux, and is slightly less than 20% of the maximum value. When an exciting current of the same polarity is applied to the plane coil (2) 43, the thrust characteristic as shown by the dotted line is shown, and the shape is the same as that of the thick line, except that it is shifted by one plane coil. Therefore, the tip 31 is a flat coil
(1) When the boundary between the plane coil (2) 43 and the plane coil (2) 43 is reached, the exciting current of the plane coil (1) 42 is cut off, and the plane coil (2) 43
Then, the thrust when the mover 3 moves by one-phase excitation moves from the solid line to the dotted line by the method of passing an exciting current of the same polarity to the above. In this manner, when the exciting current is sequentially switched when the tip 31 reaches the boundary of the planar coil, a continuous thrust characteristic as shown in FIG. 2C is exhibited.

On the other hand, the suction force characteristic shown in FIG.
If the planar coil (1) 42 is energized, the tip 31
From the small value in the state of FIG. 2A, as the tip 31 moves to the upper part of the planar coil (1) 42, it slightly increases and reaches the upper part of the planar coil (2) 43. And increase sharply. When an exciting current of the same polarity is applied to the planar coil (2) 43, the attractive force characteristic shown by the dotted line is exhibited. Therefore, when the tip 31 reaches the boundary between the planar coil (1) 42 and the planar coil (2) 43, the exciting current of the planar coil (1) 42 is cut off, and the exciting current of the same polarity is applied to the planar coil (2) 43. With the method of passing a current, the attraction force when the mover 3 moves by one-phase excitation moves from the solid line to the dotted line. In this way, when the exciting current is sequentially switched when the tip 31 reaches the boundary of the planar coil, a continuous attractive force characteristic as shown in FIG. It does not increase rapidly.

The mover 3 of this linear electromagnetic microactuator is supported by an insulator layer 45 covering the surfaces of a plurality of planar coils, but the attraction generated when the mover 3 is driven is very small. Therefore, if measures are taken to reduce surface friction, no special support mechanism as in the prior art is required. For example, a flat coil is composed of a thin-film coil, and an insulator layer (e.g., a polyimide layer) formed on the surface of the coil to insulate the coil conductor is only flattened. To fulfill. If a layer of a low friction material such as diamond-like carbon, molybdenum disulfide, boron nitride, or fluororesin is formed on the surface of the insulator layer, or if a low friction material is used as the insulator layer, friction due to suction force is generated. The power can be further reduced. This frictional force reducing effect is similarly effective in the following embodiments.

Although the block-like movable element 3 is shown in the figure, similar characteristics can be obtained with a box-shaped movable element or a box-type without an upper lid. Further, in the above example, the method of switching the plane coil to be energized one by one has been described.
Ripple of thrust can be reduced by energizing the two coils of the plane coil immediately before the movement direction and the next plane coil at the same time or overlapping for a time when the tip is near the boundary of the plane coil. . That is, F _v1 in FIG. 2C can be doubled.
This ripple reduction effect is similarly effective in the following embodiments.

[Second Embodiment] In this embodiment, the movable element in the first embodiment is a boat-shaped magnetic movable element having a flat bottom surface.
It is three times the size of 41. FIG. 3 shows a magnetic flux distribution, a thrust characteristic, and an attractive force characteristic in a case where the plane coil through which the exciting current flows is the plane coil (1) 42 immediately before the tip 52 of the bottom surface on the moving direction side of the mover 5, As in the case of FIG. 2, (a) is a magnetic flux distribution diagram, (b) is a thrust characteristic diagram for moving the mover 5, and (c) is an excitation plane coil that
Thrust characteristic diagram when switching sequentially according to the movement of
(d) is a suction force characteristic diagram for sucking the mover 5 toward the stator,
(e) is an attraction force characteristic diagram corresponding to (c).

The horizontal axis in (b) to (e) indicates the position of the tip 52 on the bottom surface of the mover 5, and the solid line in (b) and (d) indicates that the exciting current has flowed through the planar coil (1) 42. In this case, the dotted line corresponds to the case where an exciting current is passed through the planar coil (2) 43.
The equivalent of condition (a) is that in (b) and (d)
It corresponds to the vicinity of the right end of the solid line, and corresponds to the bottom of the valley in (c) and (e).

The characteristic diagrams (b) to (e) are qualitatively the same as those in the first embodiment, but the characteristics are improved in small points. Specifically, the first as shown in FIG.
The case of the shape corresponding to the second embodiment as shown in FIG. 4B is compared with the case of the shape corresponding to the second embodiment. That is, a movable element composed of a rectangular magnetic block having a side sectional shape of 1 mm × 3 mm corresponding to the first embodiment and a movable element corresponding to the second embodiment having a bottom surface of 3 mm and 45 ° on both sides.
Comparing the case of a boat-type mover consisting of a magnetic plate with a thickness of 0.1 mm, which is opened by 1 mm at a time, the thrust is as shown in Fig. 2 (c).
And the maximum values of thrust (F _p1 and F _p2 ) shown in FIG. 3 (c).
And the minimum value of the thrust (F _v1 and F _v2 ) is F _p2 ≒ 1.05 F _p1, F _v2 11.65 F _v1 , and the boat type mover is larger. (c) Since the rate of increase in the valleys in the figure is large, the ripple characteristics are improved. In terms of suction force, both are very small.

The thrust is larger in the case of the boat type mover because there is a portion that is obliquely projecting.
This is considered to be an effect of shortening the magnetic path length. The box-shaped mover described in the first embodiment and the boat-shaped mover of the second embodiment are effective because the weight of the mover itself with respect to the obtained thrust can be reduced. In the above two embodiments, the mover of the actuator is made of a magnetic material. However, when the article to be conveyed is a magnetic substance, the article can be directly conveyed depending on its shape.

[Third Embodiment] In this embodiment, the mover in the first embodiment is a permanent magnet mover, and the dimensions and the mutual arrangement of the stator and the mover are the same as those of the first embodiment. This is the same as the embodiment. FIGS. 5A and 5B show the magnetic flux distribution, the thrust characteristics and the attraction force characteristics of the permanent magnet mover 6, and FIG. 5A shows the magnetic flux distribution diagram, and FIG. (C) is a thrust characteristic diagram when the exciting plane coil is sequentially switched according to the movement of the mover 6,
(d) is a suction force characteristic diagram for sucking the mover 6 toward the stator,
(e) is a suction force characteristic diagram corresponding to (c).

In the case of the permanent magnet mover 6, the direction of the exciting current is limited because the polarity of the planar coil needs to attract the permanent magnet. In the figure, the lower surface of the permanent magnet is an N pole, and the upper surface is an S pole. Correspondingly, an exciting current is applied to the planar coil (1) 42 so that the upper surface is an S pole. (b) to (e) are the same as in the first embodiment, and a description thereof will be omitted.

The effect of using a permanent magnet as a mover is as follows.
By adding the magnetic flux of the permanent magnet to the magnetic flux of the planar coil, the thrust increases accordingly.
However, the suction force also increases by that amount, but does not reach a value that causes a problem. In this embodiment, the permanent magnets having the magnetic poles on the upper and lower sides are shown, but permanent magnets having the magnetic poles on the left and right are similarly effective.

Further, in the above embodiment, only the permanent magnet is shown as the mover 6, but a yoke made of a magnetic material is mounted on the permanent magnet to reduce the leakage magnetic flux above the permanent magnet and to reduce the thrust. It can be further increased. Furthermore, even when the article to be conveyed is a magnetic substance, the yoke prevents the article from being attracted to the mover, and enables the conveyance of the article made of a magnetic substance.

[0031]

According to the present invention, a stator consisting of a plurality of planar coils arranged one-dimensionally or two-dimensionally and an insulator layer provided on the surface thereof, and a magnetic material or a permanent magnet are used. A linear electromagnetic microactuator is constructed with the mover, and the exciting current does not flow through the plane coil immediately below the mover, but the exciting coil flows through the plane coil on the moving direction side. The suction force with the child is mainly used as the thrust of the mover to reduce the suction force toward the stator.

For this reason, the mover can move one-dimensionally or two-dimensionally on the insulator layer of the stator, and requires complicated tooth processing and a special support mechanism like the conventional LPM. do not need. Therefore, according to the present invention, there is no need to process the tooth shape, and no strong vertical suction force is generated between the mover and the stator, and therefore, no special support mechanism is required. A linear electromagnetic microactuator capable of moving the mover two-dimensionally can be provided.

[Brief description of the drawings]

FIG. 1 is a perspective view showing the configuration of a first embodiment of a linear electromagnetic microactuator according to the present invention.

FIGS. 2A and 2B show a magnetic flux distribution and characteristics in the first embodiment of the present invention, wherein FIG. 2A is a magnetic flux distribution diagram, FIG. 2B is a diagram showing thrust applied to the mover by one planar coil, and FIG. Is a diagram showing the thrust received by the mover in the continuous drive state,
(D) is a diagram illustrating the attraction force applied to the mover by one planar coil, and (e) is a diagram illustrating the attraction force applied to the mover in a continuous driving state.

3A and 3B show magnetic flux distribution and characteristics in a second embodiment of the present invention, wherein FIG. 3A is a magnetic flux distribution diagram, FIG. 3B is a diagram showing a thrust applied to the mover by one planar coil, and FIG. Is a diagram showing the thrust received by the mover in the continuous drive state,
(D) is a diagram illustrating the attraction force applied to the mover by one planar coil, and (e) is a diagram illustrating the attraction force applied to the mover in a continuous driving state.

4A and 4B show examples of the shape of each mover in the first embodiment and the second embodiment, wherein FIG. 4A is a side view showing an example of the shape of the first embodiment, and FIG. Side sectional view showing a shape example of an embodiment

5A and 5B show a magnetic flux distribution and characteristics in a third embodiment of the present invention, wherein FIG. 5A is a magnetic flux distribution diagram, FIG. 5B is a diagram showing thrust applied to the mover by one planar coil, and FIG. Is a diagram showing the thrust received by the mover in the continuous drive state,
(D) is a diagram illustrating the attraction force applied to the mover by one planar coil, and (e) is a diagram illustrating the attraction force applied to the mover in a continuous driving state.

FIG. 6 is a conceptual diagram showing a configuration and a driving state of a conventional linear electromagnetic microactuator.

FIG. 7 is a diagram showing an energized state when a conventional linear electromagnetic microactuator is driven.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Mover 11 First magnetic pole 12 Second magnetic pole 13 Third magnetic pole 14 Fourth magnetic pole 15 Permanent magnet 2 Stator 21 Stator teeth 3 Magnetic body mover 31 Tip of mover 4 Stator 41 Planar coil 42 Plane coil (1) 43 Plane coil (2) 44 Plane coil (3) 45 Insulator layer 5 Boat-shaped magnetic mover 51 Tip of mover 52 Tip of bottom face 6 Permanent magnet mover 61 Tip of mover Department

Claims (5)

(57) [Claims] 1. A consists of a one-dimensional or two-dimensionally arranged an insulator layer provided in the plurality of planar coils and the surface has a stator, a movable element made of magnetic material, movable Linear electromagnetic type
An microactuator, which does not excite a planar coil immediately below the center of the mover , but excites one or more planar coils on the side in which the mover is moved from the planar coil in a one-phase manner; A linear electromagnetic microactuator characterized by moving a member on an insulator. 2. The linear electromagnetic microactuator according to claim 1, wherein the mover made of a magnetic material has a boat shape with a flat bottom surface. 3. The method according to claim 2, wherein the magnetic material is a permanent magnet.
The linear electromagnetic microactuator according to claim 1 . 4. The linear electromagnetic microactuator according to claim 1, wherein the insulator layer is made of a low friction material. 5. The insulating layer according to claim 1, further comprising a layer made of a low-friction material on a surface thereof.
The linear electromagnetic microactuator according to any one of the above.