WO2013047610A1

WO2013047610A1 - Actuator

Info

Publication number: WO2013047610A1
Application number: PCT/JP2012/074766
Authority: WO
Inventors: 柴田　均; 谷口　繁; 鈴木　浩史
Original assignee: Thk株式会社
Priority date: 2011-09-28
Filing date: 2012-09-26
Publication date: 2013-04-04
Also published as: JPWO2013047610A1; TW201325030A

Abstract

This actuator is provided with: magnet units such that the N-poles and S-poles are disposed alternately facing a first direction respectively at first surfaces and second surfaces that trail each other; and a coil unit having a plurality of c-shaped cores of which the first ends face the first surfaces and the second ends face the second surfaces, and a plurality of coils wound around the plurality of c-shaped cores. The plurality of c-shaped cores are arrayed facing in the first direction, are disposed to one side in a second direction with the magnet units as a baseline, and are disposed far from each other to both sides in a third direction with the magnet units as a baseline.

Description

Actuator

The present invention relates to an actuator.
This application claims priority based on Japanese Patent Application No. 2011-212953 filed in Japan on September 28, 2011, the contents of which are incorporated herein by reference.

Patent Document 1 discloses an ultra-precision positioning linear motor.

FIG. 11 is a perspective view showing a schematic configuration of a conventional linear motor 100. FIG. 12 is a side view of a conventional linear motor 100.
The linear motor 100 has substantially the same configuration as the linear motor disclosed in Patent Document 1. The linear motor 100 includes a plurality of armatures (primary side) having a core 103 and a magnet unit 106 (secondary side) having a permanent magnet.
The core 103 is formed with a local portion (gap) where the upper magnetic pole teeth and the lower magnetic pole teeth face each other. The core 103 is formed such that a portion on the upper magnetic pole tooth side and a portion on the lower magnetic pole tooth side extend in opposite directions in the left-right direction when viewed from the traveling direction of the linear motor 100. An IL 104 is wound around each of the cores 103.

Japanese Patent No. 4089597

The armature (core 103) of the conventional linear motor 100 is not a circular outer shape but a complicated ring shape having many bent portions. For this reason, the magnetic field generated in the armature (core 103) has a problem that magnetic saturation occurs because the magnetic path becomes long.

In the conventional linear motor 100, the magnet unit 106 is inserted into the gap of the armature (gap of the core 103). The magnet part 106 is a both-ends support structure that supports both ends in the longitudinal direction. For this reason, when the magnet part 106 becomes long in the longitudinal direction, the central part of the magnet part 106 is bent by its own weight, so that it is necessary to increase the gap between the armatures (core 103). Therefore, the conventional linear motor 100 has a problem that the nonlinearity of the thrust with respect to the current appears in the magnetic saturation region and the controllability is deteriorated.

Further, in the conventional linear motor 100, there is a problem that a sufficient moving distance cannot be secured if the magnet portion 106 is shortened to prevent bending.

An object of the present invention is to provide an actuator capable of efficient and precise positioning.

In the first embodiment of the actuator according to the present invention, the N pole and the S pole are alternately arranged in the first direction on the first surface and the second surface facing each other, and the first surface The magnet part where the polarity of the surface and the polarity of the second surface are opposite to each other, the first end part is opposed to the first surface with a gap, and the second end part is a gap with respect to the second surface. A plurality of C-shaped cores facing each other and a coil portion having a plurality of coils wound around the plurality of C-shaped cores, the plurality of C-shaped cores being arranged in the first direction, The ring-shaped part of the C-shaped core is arranged on one side with respect to the magnet part in a second direction orthogonal to the first direction and parallel to the first surface and the second surface, and , Orthogonal to the first direction and the first surface and the They are staggered on opposite sides with respect to the said magnet portion in a third direction orthogonal to the second surface.

According to a second embodiment of the actuator according to the present invention, in the first embodiment according to the present invention, the coil corresponds to an annular portion of another adjacent C-shaped core among the annular portions of the C-shaped core. A first coil wound around a first region that does not overlap in the first direction.

A third embodiment of the actuator according to the present invention is the first or second embodiment according to the present invention, wherein the coil is relative to another adjacent C-shaped core among the ring-shaped portions of the C-shaped core. A second coil wound around a second region that does not overlap in the first direction.

In a fourth embodiment of the actuator according to the present invention, in any one of the first to third embodiments according to the present invention, the ring-shaped portion of the C-shaped core has a ring shape.

A fifth embodiment of the actuator according to the present invention is the actuator according to any one of the first to fourth embodiments according to the present invention, wherein the cross-sectional shape of the ring-shaped portion of the C-shaped core is the first end portion. It is the same shape over the two ends.

A sixth embodiment of the actuator according to the present invention is the encoder according to any one of the first to fifth embodiments according to the present invention, further comprising an encoder that detects a relative position between the magnet portion and the coil portion. Is disposed in proximity to the thrust generation location by the magnet portion and the coil portion.

According to the actuator of the present invention, a large driving force can be obtained by suppressing magnetic saturation, so that efficient and precise positioning can be performed.

It is a perspective view showing a schematic structure of a linear motor concerning an embodiment of the present invention. It is a principal part perspective view of a linear motor. It is a front view (partial sectional view) showing a schematic configuration of a linear motor. It is a figure which shows a core. It is sectional drawing which shows schematic structure of a coil part. It is a top view which shows schematic structure of a coil part. It is a side view which shows schematic structure of a coil part. It is a circuit diagram which shows the connection aspect of the outer side coil of each phase of U, V, and W, and an inner side coil. It is a circuit diagram which shows the other connection aspect of the outer side coil of each phase of U, V, and W, and an inner side coil. It is a figure which shows magnetic flux density distribution of the core of a linear motor. (A) shows the case of the supply current 5A, (b) shows the case of the supply current 10A, (c) shows the case of the supply current 20A, and (d) shows the case of the supply current 30A. It is a figure (reference example) which shows the magnetic flux density distribution of a core in case there is no inner side coil (auxiliary coil). (A) shows the case of the supply current 5A, (b) shows the case of the supply current 10A, (c) shows the case of the supply current 20A, and (d) shows the case of the supply current 30A. It is a perspective view which shows schematic structure of the conventional linear motor. It is a side view of the conventional linear motor. It is a figure which shows magnetic flux density distribution of the core of the conventional linear motor. (A) shows the case of the supply current 5A, (b) shows the case of the supply current 10A, (c) shows the case of the supply current 20A, and (d) shows the case of the supply current 30A. It is a perspective view which shows the installation aspect of a linear encoder. It is a front view which shows the installation aspect of a linear encoder.

FIG. 1 is a perspective view showing a schematic configuration of a linear motor 1 according to an embodiment of the present invention.
FIG. 2 is a perspective view of a main part of the linear motor 1 with the table 20 removed.
FIG. 3A is a front view (partially sectional view) showing a schematic configuration of the linear motor 1. FIG. 3B is a diagram showing the U-phase core 61.

The traveling direction of the table 20 is the X direction (first direction), orthogonal to the X direction, the direction parallel to the top surface of the table 20 is the Y direction (third direction), and the direction perpendicular to the top surface of the table 20 is the Z direction (first direction). Bidirectional).
In each figure, the direction indicated by each arrow on the coordinate axis is referred to as a + direction, and the direction opposite to each arrow is referred to as a − direction.

In the following, in order to describe the characteristics of the linear motor 1, it will be described in comparison with the conventional linear motor 100 as appropriate (see FIGS. 11 and 12).

The linear motor (actuator) 1 is a magnetic attractive force cancel type. The linear motor 1 includes a base 10 that is elongated in one direction (X direction) and a table 20 that is slidable with respect to the base 10.
A pair of linear guides 50 is provided between the base 10 and the table 20. For this reason, the table 20 can slide smoothly along the longitudinal direction of the linear guide 50 with respect to the base 10.

The base 10 includes an elongated rectangular bottom wall portion 11 and a pair of side wall portions 12 provided perpendicular to both ends in the width direction (Y direction) of the bottom wall portion 11. The base 10 is made of, for example, a magnetic material such as steel or a nonmagnetic material such as aluminum.
A magnet portion 30 in which a plurality of permanent magnets 33 are arranged in the X direction is disposed at the center of the upper surface of the bottom wall portion 11 of the base 10.
Track rails 51 of the linear guide 50 are arranged along the X direction on the upper surfaces of the side wall portions 12 of the base 10. The two track rails 51 are arranged substantially in parallel. A moving block 52 is attached to each track rail 51.

The table 20 is made of a nonmagnetic material such as aluminum and is formed in a rectangular plate shape.
The moving blocks 52 of the linear guide 50 are attached to the four corners on the lower surface side of the table 20, respectively. Each moving block 52 is attached to the two track rails 51 described above. Accordingly, the table 20 is supported by the four sets of linear guides 50 in a state in which the table 20 can linearly move with respect to the base 10.
In addition, a coil portion 40 that functions as a three-phase coil is provided on the lower surface of the table 20. The coil unit 40 is disposed in a region surrounded by the four moving blocks 52 on the lower surface of the table 20.

The magnet unit 30 includes an elongated thin plate-like magnet plate 31, a bottom plate 32 that fixes the magnet plate 31, and a plurality of permanent magnets 33 attached to both surfaces of the magnet plate 31. The permanent magnet 33 is made of, for example, neodymium.
The magnet plate 31 is fixed so as to be orthogonal to the Y direction while being orthogonal to the bottom plate 32 (the bottom wall portion 11 of the base 10). The magnet plate 31 has a longitudinal direction formed along the X direction and a short side direction formed along the Z direction.
The magnet plate 31 is inserted into a part (a gap g described later) of the coil portion 40 disposed on the lower surface of the table 20.

The magnet plate 31 has a first surface 31a and a second surface 31b that are orthogonal to the Y direction and face each other. On the first surface 31a and the second surface 31b of the magnet plate 31, N-pole and S-pole permanent magnets 33 are alternately arranged in the X direction. The polarity of the permanent magnet 33 disposed on the first surface 31 a is opposite to the polarity of the permanent magnet 33 disposed on the second surface 31 b facing away from the permanent magnet 33. That is, on the first surface 31a, from the −X direction to the + X direction (see FIG. 4, from the lower side to the upper side in FIG. 4), the N pole, the S pole, the N pole, the S pole,. The permanent magnets 33 are alternately arranged. On the other hand, permanent magnets 33 of S pole, N pole, S pole, N pole,... Are alternately arranged on the second surface 31b from the −X direction to the + X direction.
The permanent magnets 33 arranged on the first surface 31 a and the second surface 31 b of the magnet plate 31 generate a magnetic field inside the coil unit 40 when entering the gap g of the coil unit 40.

The magnet unit 30 is different from the both-end support structure employed by the magnet unit 106 of the conventional linear motor 100 (see FIG. 11). The magnet unit 30 employs a full support structure in which the entire area of the end surface of the magnet plate 31 in the −Z direction (the lower side in FIG. 3A) is supported by the bottom plate 32. For this reason, as for the magnet part 30, the magnet plate 31 does not bend by own weight.

FIG. 4 is a cross-sectional view (a view showing a cross section perpendicular to the Z direction) showing a schematic configuration of the coil section 40. FIG. 5 is a top view of the coil unit 40. FIG. 6 is a side view of the coil unit 40.

The coil unit 40 is a U, V, W three-phase coil. Each of the three-phase coils has a C-shaped core and a coil wound around the core.
Specifically, the coil unit 40 includes U-phase cores (C-shaped cores) 61, 62, 63, 64, U-phase outer coils (first coils) 66, 68, U-phase inner coils (second coils) 67, 69, V-phase core (C-shaped core) 71, 72, 73, 74, V-phase outer coil (first coil) 76, 78, V-phase inner coil (second coil) 77, 79, W-phase core (C-shaped) Core) 81, 82, 83, 84, W-phase outer coils (first coils) 86, 88, and W-phase inner coils (second coils) 87, 89.

The core and coil of each phase of U, V, and W have the same configuration and the same shape. Therefore, the U phase will be mainly described below. The core shape will be described mainly with respect to the U-phase core 61.

The material of the

U-phase cores

61, 62, 63, 64 is a magnetic material such as silicon steel.
As shown in FIGS. 3A to 6, the

U-phase cores

61, 62, 63, and 64 have the same shape. The

U-phase cores

61, 62, 63, 64 are formed in a C-shaped ring shape and have a gap g that is a gap into which the magnet plate 31 can be inserted. The

U-phase cores

61, 62, 63, 64 have a shape that is sandwiched across the magnet part 30.
The C-shape means an incomplete annular shape having a cut (gap g) in a part of the circumferential direction of a portion (annular portion 61c) formed in an annular shape. The C-shape includes an annular member having a gap g at one place, such as a U-shape or a horseshoe shape. The ring-shaped part 61c is a part excluding the first end part 61a and the second end part 61b that form the gap g.

Although the

U-phase cores

61, 62, 63, and 64 have a bent portion or a straight portion, they are formed in a C-shape that is generally an arc shape.
The

U-phase cores

61, 62, 63, 64 have a substantially uniform cross-sectional shape (a cross-sectional shape perpendicular to the magnetic path (magnetic flux direction)) in any part of the

U-phase cores

61, 62, 63, 64. (Rectangular).

All of the

U-phase cores

61, 62, 63, 64 are arranged with the gap g directed in the −Z direction where the magnet part 30 is arranged. The

U-phase cores

61, 62, 63, 64 are arranged at equal intervals in the X direction in a state parallel to each other in the Y direction. All of the ring-shaped portions (61c) of the

U-phase cores

61, 62, 63, and 64 are arranged toward the + Z direction (the upper side in FIG. 3A) with respect to the magnet portion 30.

Of the

U-phase cores

61, 62, 63, 64, one end surface (first end portion 61 a) that forms the gap g does not contact the first surface 31 a of the magnet plate 31 and has a constant gap. Opposite each other. Of the

U-phase cores

61, 62, 63, 64, the other end surface (second end portion 61 b) that forms the gap g does not contact the second surface 31 b of the magnet plate 31 and has a certain gap. Opposite each other.

When viewed from the X direction (see FIG. 3A), the ring-shaped portion (61c) of the

U-phase core

61, 62, 63, 64 has a center (center of gravity) in the + Y direction or the magnet portion 30 (magnet plate 31). -It is in a position shifted (offset) in the Y direction.
The ring-shaped portions (61c) of the

U-phase cores

61 and 63 are arranged so as to be offset in the + Y direction (the left side in FIG. 3A). The ring-shaped portions (61c) of the

U-phase cores

62 and 64 are arranged so as to be offset in the −Y direction (the right side in FIG. 3A).
The ring-shaped portions (61c) of the

U-phase cores

61 and 63 and the

U-phase cores

62 and 64 are symmetrical with respect to an axis (not shown) in the Z direction passing through the magnet plate 31 of the magnet portion 30. Placed in. The ring-shaped portions (61c) of the

U-phase cores

61, 62, 63, and 64 are alternately arranged in the Y direction with respect to the magnet portion 30, and are arranged in the X direction.

The

U-phase cores

61, 62, 63, and 64 are not complicated ring shapes that the core 103 of the conventional linear motor 100 has (see FIG. 12). The

U-phase cores

61, 62, 63, 64 are formed in a C-shape that is generally arcuate. For this reason, the

U-phase cores

61, 62, 63, 64 have a shorter magnetic path than the core 103 of the conventional linear motor 100.
The cross-sectional shape of the

U-phase cores

61, 62, 63, 64 does not vary greatly depending on the location as in the core 103 of the conventional linear motor 100 (see FIG. 12). The

U-phase cores

61, 62, 63, 64 have a substantially uniform cross-sectional shape at any portion.
The gap g of the

U-phase cores

61, 62, 63, 64 is formed narrower than the gap of the core 103 of the conventional linear motor 100.
Therefore, the

U-phase cores

61, 62, 63, 64 are less likely to be magnetically saturated compared to the core 103 of the conventional linear motor 100.

As shown in FIGS. 3A to 6, the

U-phase cores

61, 62, 63, 64 have coils (U-phase outer coils 66, 64) in the portion farthest from the magnet unit 30 (magnet plate 31) in the Y direction. 68) is wound.
In the

U-phase cores

61 and 63, a U-phase outer coil (coil, first coil) 66 is wound around a portion (region) farthest from the magnet plate 31 in the + Y direction. In the X direction (see FIG. 3A), the U-phase outer side of the annular region (61c) of the

U-phase cores

61 and 63 is not overlapped with the annular region (61c) of the adjacent

U-phase cores

62 and 64. A coil 66 is wound. One U-phase outer coil 66 is wound around the pair of

U-phase cores

61 and 63.
In the

U-phase cores

62 and 64, a U-phase outer coil (coil, first coil) 68 is wound around a portion farthest from the magnet plate 31 in the −Y direction. In the Y direction, the U-phase outer coil 68 is wound on the first region 61d that does not overlap the annular portion (61c) of the adjacent

U-phase cores

61 and 63 among the annular portions (61c) of the

U-phase cores

62 and 64. . One U-phase outer coil 68 is wound around the pair of

U-phase cores

62 and 64.

Coils (U-phase inner coils 67 and 69) are wound around the

U-phase cores

61, 62, 63, and 64 in regions (regions) close to the magnet plate 31 in the Y direction.
In the

U-phase cores

61, 63, a U-phase inner coil (coil, second coil) 67 is wound at a portion farthest in the −Y direction from the U-phase outer coil 66. In the X direction (see FIG. 3A), the U-phase inner coil 67 is formed in the second region 61 e that does not overlap the annular portion (61 c) of the adjacent

U-phase cores

62, 64 among the annular portions 61 c of the

U-phase cores

61, 63. Is wound. One U-phase inner coil 67 is wound around the pair of

U-phase cores

61 and 63.
In the

U-phase cores

62 and 64, a U-phase inner coil (coil, second coil) 69 is wound at a position farthest from the U-phase outer coil 68 in the + Y direction. In the X direction, the U-phase inner coil 69 is wound around the second region 61e that does not overlap the annular portion (61c) of the adjacent

U-phase cores

61 and 63 among the annular portions (61c) of the

U-phase cores

62 and 64. . One U-phase inner coil 69 is wound around the pair of

U-phase cores

62 and 64.

The U-phase

inner coils

67 and 69 are closer to the magnet unit 30 than the U-phase

outer coils

66 and 68. When viewed from the X direction (see FIG. 3A), the first region 61d is a region away from the magnet unit 30 among the two regions that do not overlap the adjacent U-phase core in the ring-shaped portion 61c. On the other hand, the second region 61e is a region adjacent to the magnet unit 30 among the two regions that do not overlap the adjacent U-phase core in the annular portion 61c.

The number of coil turns of the U-phase

outer coils

66 and 68 and the U-phase

inner coils

67 and 69 is about half that of the U-phase

outer coils

66 and 68. It is set as follows.

FIG. 7 is a circuit diagram showing a connection mode of the outer and inner coils of each of U, V, and W phases.
A U-phase outer coil 66 and a U-phase inner coil 67 wound around the same core pair (U-phase cores 61 and 63) are connected in series.
The U-phase outer coil 68 and the U-phase inner coil 69 wound around another identical core pair (U-phase cores 62 and 64) are connected in series.
Furthermore, the series connection circuit of the U-phase outer coil 66 and the U-phase inner coil 67 and the series connection circuit of the U-phase outer coil 68 and the U-phase inner coil 69 are connected in series (U-phase series circuit).
A three-phase alternating current is supplied to the U-phase series circuit.

Also in the V phase and the W phase, an outer coil (V phase outer coil 76, W phase outer coil 86) and an inner coil (V) wound around the same core pair (

V phase cores

71 and 73, W phase cores 81 and 83). A phase inner coil 77 and a W phase inner coil 87) are connected in series.
An outer coil (V-phase outer coil 78, W-phase outer coil 88) and inner coil (V-phase inner coil 79, W) wound around another identical core pair (V-

phase cores

72, 74, W-phase cores 82, 84). A phase inner coil 89) is connected in series.
Further, two series connection circuits are connected in series (V phase series circuit, W phase series circuit).
A three-phase alternating current is also supplied to the V-phase series circuit and the W-phase series circuit.

The connection mode of the outer coil and the inner coil of each phase may be as follows.
FIG. 8 is a circuit diagram showing another connection mode of the outer and inner coils of each phase of U, V, and W.
A U-phase outer coil 66 and a U-phase inner coil 67 wound around the same core pair (U-phase cores 61 and 63) are connected in series.
The U-phase outer coil 68 and the U-phase inner coil 69 wound around another identical core pair (U-phase cores 62 and 64) are connected in series.
Furthermore, the series connection circuit of the U-phase outer coil 66 and the U-phase inner coil 67 and the series connection circuit of the U-phase outer coil 68 and the U-phase inner coil 69 are connected in parallel (U-phase parallel circuit).
A three-phase alternating current is supplied to the U-phase parallel circuit.

V phase cores

71 and 73, W phase cores 81 and 83). A phase inner coil 77 and a W phase inner coil 87) are connected in series.
Outer coil (V-phase outer coil 78, W-phase outer coil 88) and inner coil (V-phase inner coil 79, W-phase inner side) wound around the same core pair (V-

phase cores

72, 74, W-phase cores 82, 84) A coil 89) is connected in series.
Further, two series connection circuits are connected in parallel (V phase parallel circuit, W phase parallel circuit).
A three-phase alternating current is also supplied to the V-phase parallel circuit and the W-phase parallel circuit.

In the linear motor 1 configured as described above, three-phase alternating currents having different phases by 120 degrees are passed through the coils of the U, V, and W phases. As a result, a traveling magnetic field is generated from the coil unit 40. And a thrust generate | occur | produces in the coil part 40 (table 20) by the effect | action of the advancing magnetic field generate | occur | produced in the coil part 40, and the magnetic field generated in the magnet part 30. FIG.

FIG. 9 is a diagram showing the magnetic flux density distribution of the

U-phase cores

61 and 62 of the linear motor 1.
FIG. 10 is a diagram showing the magnetic flux density distribution of the

U-phase cores

61 and 62 when the

inner coils

67 and 69 are not provided as a reference example.
FIG. 13 is a diagram showing the magnetic flux density distribution of the core 103 of the conventional linear motor 100.
9 and 10 are views of the

U-phase cores

61 and 62 viewed from the X direction, and only the

U-phase cores

61 and 62 are shown.
FIG. 13 is a view of the U-phase core 103 as viewed from the X direction, and shows only the U-phase core 103.
9 and 10, the supply current to the coil unit 40 is increased in the order of (a) to (d). (A) shows the supply current 5A, (b) shows the supply current 10A, (c) shows the supply current 20A, and (d) shows the supply current 30A.
Similarly, in FIG. 13, the supply current to the coil section is increased in the order of (a) to (d). (A) shows the case of the supply current 5A, (b) shows the case of the supply current 10A, (c) shows the case of the supply current 20A, and (d) shows the case of the supply current 30A.

As shown in FIG. 9, the

U-phase cores

61 and 62 have a uniform magnetic flux density as a whole, although there are some portions where the magnetic flux density is slightly low in the vicinity of the gap g.
Compared to the magnetic flux density of the core 103 of the conventional linear motor 100 (FIG. 13), the

U-phase cores

61 and 62 have a high magnetic flux density and are not easily magnetically saturated.
In the

U-phase cores

61 and 62, the magnetic flux density is uniform as a whole even when the current value of the supply current is changed.

As shown in FIG. 10, the

U-phase cores

61 and 62 have a high magnetic flux density and are not easily magnetically saturated.

9 is compared with FIG. 10, the magnetic flux density is more uniform in the case of FIG. 9 than the case of FIG. 10 because the U-phase

inner coils

67 and 69 are present, and the magnetic flux density is more uniform. high.

The linear motor 1 according to the embodiment of the present invention has the following features and effects as compared to the conventional linear motor 100.
In the linear motor 1, the magnet plate 31 on which the permanent magnets 33 are arranged is fixed to the bottom plate 32, so that the magnet plate 31 does not bend due to its own weight. For this reason, the gap between the core of each phase and the magnet portion can be reduced. Therefore, the linear motor 1 can effectively use the magnetic flux.
Moreover, in the linear motor 1, there is no restriction | limiting of the movement distance of the table 20 (coil part 40) resulting from the bending of the magnet plate 31. FIG.

In the linear motor 1, the core (annular portion) of each phase has a substantially circular C shape, so that the magnetic path inside the core is shortened. The cross-sectional shape of the core (annular part) of each phase is almost uniform in any part.
Thereby, since the magnetic saturation of the core of each phase is suppressed in the linear motor 1, the propulsive force of the table 20 can be obtained smoothly according to the three-phase alternating current value. Therefore, the controllability of the linear motor 1 is improved compared to the conventional linear motor 100.

The various shapes and combinations of the constituent members shown in the above-described embodiments are merely examples, and various modifications can be made based on design requirements and the like without departing from the gist of the present invention.

FIG. 14A is a perspective view showing an installation mode of the linear encoder. FIG. 14B is a front view showing an installation mode of the linear encoder.
The linear motor 1 includes a linear encoder 90 in order to measure the position, speed, and the like of the table 20 (coil unit 40) in the X direction with respect to the base 10 (magnet unit 30).
The linear encoder 90 includes a linear scale 91 disposed on the base 10 and a detector 92 disposed on the table 20. The linear scale 91 is disposed at the upper end of the magnet plate 31. An upper end plate 35 that is parallel to the XY plane and extends in the X direction is disposed at the upper end of the magnet plate 31. The linear scale 91 is installed on the upper surface of the upper end plate 35. The detector 92 is arranged with respect to the end surface of the table 20 in the X direction via the detector fixture 25.

The installation position of the linear encoder 90 substantially coincides with (is close to) the thrust generation location (gap g) of the linear motor 1. Therefore, the relative position of the table 20 (coil part 40) with respect to the base 10 (magnet part 30) can be detected accurately.
If the linear encoder is arranged at a location away from the thrust generation location of the linear motor, a position detection error occurs due to mechanical distortion or the like, causing a control delay. For this reason, the linear motor may vibrate and precise positioning may be difficult.
On the other hand, in the linear motor 1, since the installation position of the linear encoder 90 is substantially matched (close) to the thrust generation location, almost no position detection error occurs. Therefore, the control vibration in the linear motor 1 is suppressed, and the linear motor 1 can be accurately positioned.
Moreover, in the linear motor 1, since the upper end plate 35 is provided in the magnet plate 31, the mechanical rigidity of the magnet part 30 becomes high. Accordingly, mechanical vibrations in the magnet unit 30 and the linear scale 91 are suppressed, and the linear motor 1 can be accurately positioned.

In the embodiment described above, the case where two coils (an outer coil and an inner coil) are provided for one core has been described, but the present invention is not limited to this. It may be the case where only the outer coil is provided for one core, or the case where only the inner coil (auxiliary coil) is provided for one core.

The linear motor 1 is not limited to a three-phase type, and can be applied to a two-phase type, for example.

The number of cores of each phase of the coil unit 40 is not limited to four, and any number of cores can be used.

The cross-sectional shape of the core of each phase of the coil unit 40 is not limited to a rectangle. For example, it may be polygonal, circular or elliptical. The cross-sectional shape of the core may be any shape as long as it is a substantially uniform cross-sectional shape.

DESCRIPTION OF SYMBOLS 1 ... Linear motor (actuator), 30 ... Magnet part, 31a ... First surface, 31b ... Second surface, 33 ... Permanent magnet, 40 ... Coil part, 61, 62, 63, 64 ... U-phase core (C-shaped core) ), 61a ... first end, 61b ... second end, 61c ... annular part, 61d ... first region, 61e ... second region, 66,68 ... U-phase outer coil (coil, first coil), 67 , 69 ... U-phase inner coil (coil, second coil), 71, 72, 73, 74 ... V-phase core (C-shaped core), 76, 78 ... W-phase outer coil (coil, first coil), 77, 79: W-phase inner coil (coil, second coil), 81, 82, 83, 84 ... V-phase core (C-shaped core), 86, 88 ... W-phase outer coil (coil, first coil) Le), 87, 89 ... W-phase inner coil (coil, a second coil), 90 ... linear encoder (encoder)

Claims

N poles and S poles are alternately arranged in the first direction on the first surface and the second surface facing each other, and the polarities of the first surface and the second surface are opposite to each other. A magnet section;
A plurality of C-shaped cores and a plurality of C-shaped cores having a first end opposed to the first surface with a gap and a second end opposed to the second surface with a gap A coil portion having a plurality of coils wound;
With
The plurality of C-shaped cores are arranged toward the first direction,
The ring-shaped part of the C-shaped core is arranged on one side with respect to the magnet part in a second direction orthogonal to the first direction and parallel to the first surface and the second surface, and The actuators are alternately arranged on both sides with respect to the magnet portion in a third direction orthogonal to the first direction and orthogonal to the first surface and the second surface.
The coil is
2. The actuator according to claim 1, further comprising: a first coil wound in a first region that does not overlap in the first direction with respect to an annular portion of another adjacent C-shaped core among the annular portions of the C-shaped core.
The coil is
2. The actuator according to claim 1, comprising a second coil wound in a second region that does not overlap in the first direction with respect to another adjacent C-shaped core of the ring-shaped portion of the C-shaped core.
The actuator according to claim 1, wherein the ring-shaped portion of the C-shaped core is a ring shape.
2. The actuator according to claim 1, wherein a cross-sectional shape of the ring-shaped portion of the C-shaped core is the same shape from the first end portion to the second end portion.
An encoder for detecting a relative position between the magnet part and the coil part;
The actuator according to claim 1, wherein the encoder is disposed in proximity to a thrust generation location by the magnet portion and the coil portion.