WO2017010552A1 - Linear motor magnetic field unit and linear motor - Google Patents

Abstract

A linear motor magnetic field unit 2 is provided with multiple first permanent magnets 22a, 22b having a rectangular shape in planar view and arranged in parallel on a back yoke 21 such that the magnetic poles thereof are reversed from one another and two second permanent magnets 23, 23 that have polygonal shapes in planar view, are identically shaped and the widths of which narrow in the direction of the parallel arrangement, tapering from one side to the other side along a direction that intersects the direction of the parallel arrangement, arranged with the tapering directions thereof inverted from one another on both sides of the parallel arrangement direction of the multiple first permanent magnets 22a, 22b. Via this configuration, a linear motor, etc. capable of reducing detent force, including secondary components, is provided.

Description

Linear motor field and linear motor

The present invention relates to a linear motor field portion and a linear motor including the field portion.

Semiconductor manufacturing apparatuses and liquid crystal display substrate manufacturing apparatuses are required to move a workpiece with high accuracy and low vibration in a plane perpendicular to the direction of gravity. A table on which an object to be processed or a processing tool is placed is moved by a drive source that can be moved individually on orthogonal linear guides. Since this movement requires low vibration and good accuracy, a method of changing the output of a rotary motor used in a general processing machine to a linear motion with a ball screw is not adopted as a drive source. Instead, a linear motor capable of direct translation is used as a drive source.

As a general configuration of a linear motor, a core made of a soft magnetic material including a field part as a mover (or stator) in which a plurality of permanent magnets are arranged so that the polarities are alternately changed, and a plurality of magnetic pole teeth And an armature as a stator (or mover) having a coil wound around the magnetic pole teeth. The field part and the armature are arranged opposite to each other with a predetermined distance therebetween, and an alternating current whose polarity and size are synchronized with the moving distance with respect to the field period of the field part is applied to the coil. Then, a thrust is generated in the moving direction by the attractive repulsive force with the permanent magnet, and the field part (or armature) is linearly moved with respect to the armature (or field part). Various types of linear motors having such a configuration have been proposed. For example, Patent Document 1 describes a linear motor having a field portion as a stator and an armature as a mover.

JP 2006-527576 A

∙ In a linear motor, a detent force unique to the motor is generated. This detent force causes a reduction in thrust of the linear motor and generation of unevenness in thrust. Conventionally, such a problem is dealt with by a skew arrangement in which a certain angle is provided in the arrangement row of magnetic pole teeth.

However, the skew arrangement is effective for removing high-order components of detent force, but there is a limit to removing low-order components. In particular, there is almost no effect in removing the secondary component of the change in the magnetic flux that appears as the end effect of the mover.

The present invention has been made in view of the circumstances as described above, and an object thereof is to provide a linear motor capable of reducing detent force including a secondary component.

The field portion for a linear motor according to the present invention includes a rectangular plate-shaped back yoke and a plurality of first permanent magnets that are rectangular in plan view and are arranged in parallel on the back yoke so that the magnetic poles are in opposite directions. And having a polygonal shape in plan view, the width of the juxtaposed direction is tapered from one side to the other along the direction intersecting the juxtaposed direction, and at both ends of the plurality of first permanent magnets in the juxtaposed direction And two second permanent magnets having the same shape and arranged with the taper directions reversed from each other.

In the present invention, by providing the second permanent magnets at both ends of the first permanent magnet row, the detent force including the secondary component can be reduced.

The linear motor field part according to the present invention is characterized in that the sum of the width dimensions of both ends of the second permanent magnets in the juxtaposed direction is substantially the same as the width dimension of the first permanent magnets in the juxtaposed direction. To do.

In the present invention, the sum of the dimensions of both ends of the second permanent magnets in the juxtaposed direction is substantially the same as the dimension of the first permanent magnets in the juxtaposed direction, so that the characteristics of the linear motor are maintained. Is possible.

In the field part for a linear motor according to the present invention, the width dimension of both ends of the second permanent magnets in the juxtaposition direction is such that the ratio of one to the other is in the range of 10: 1 to 1: 1. .

In the present invention, since the ratio of the dimensions of both ends of the second permanent magnet is in the range of 10: 1 to 1: 1, the detent force including the secondary component can be reduced.

The field part for a linear motor according to the present invention is characterized in that the second permanent magnet has a trapezoidal shape in plan view.

In the present invention, since the second permanent magnet has a trapezoidal shape in plan view, it is possible to easily create the second permanent magnet.

The field part for a linear motor according to the present invention is characterized in that the second permanent magnet has a substantially triangular shape in plan view.

In the present invention, since the second permanent magnet has a substantially triangular shape in plan view, it is possible to reduce the detent force including the secondary component.

The field part for a linear motor according to the present invention is characterized in that the two second permanent magnets are arranged so as to be symmetrical with respect to each other in plan view with a predetermined point of the back yoke as a center.

In the present invention, since the two second permanent magnets are arranged so as to be point-symmetric, the characteristics of the linear motor can be maintained.

A linear motor according to the present invention includes an armature having a rectangular plate-shaped substrate portion and a plurality of magnetic pole teeth wound with coils arranged in parallel to the substrate portion, and the linear motor field described above. It comprises a part.

In the present invention, the detent force including the secondary component can be reduced.

The armature of the linear motor according to the present invention includes auxiliary teeth that are provided at intervals from the magnetic pole teeth at the end in the parallel arrangement direction of the substrate portions and do not wind the coil. The tip portion is larger than the root portion, and the auxiliary teeth and the magnetic pole teeth adjacent to the auxiliary teeth are directly facing in the juxtaposed direction.

In the present invention, since the auxiliary teeth are flush with the magnetic pole teeth, the magnetic flux can be allowed to flow between the stator and the magnetic pole teeth.

The linear motor according to the present invention is characterized in that the armature is a stator and the linear motor field part is a mover.

In the present invention, the detent force including the secondary component can be reduced.

It is a perspective view which shows one structural example of a linear motor. It is a perspective view which shows the structure of the stator except a coil. It is a perspective view which shows the structure of a needle | mover. It is a top view which shows the structure of a needle | mover. It is a side view of a linear motor. It is a graph which shows the detent force of a linear motor. It is explanatory drawing which shows another structure of the stator except a coil.

Hereinafter, embodiments will be described in detail with reference to the drawings. FIG. 1 is a perspective view showing a configuration example of the linear motor 100. The linear motor 100 includes a stator 1 that is long in one direction and has a rectangular parallelepiped shape, and a mover 2 that faces a part of the stator 1 with a slight gap therebetween. In the mover 2, permanent magnets (first permanent magnets) 22 a and 22 b and a permanent magnet (second permanent magnet) 23 are arranged in parallel on a rectangular plate-like back yoke 21. The mover 2 is configured to move in the longitudinal direction of the stator 1 (the arrow direction in FIG. 1 or the reverse direction of the arrow). In the linear motor 100 of the present embodiment, the armature is the stator 1 and the field part is the mover 2.

FIG. 2 is a perspective view showing the configuration of the stator 1 excluding the coil 14. The stator 1 includes magnetic pole tooth parts 11 and 12 and an auxiliary pole tooth part 13. The magnetic pole tooth part 11 includes a rectangular plate-like substrate portion 11a and two rectangular plate-like tooth portions 11b that rise vertically from the substrate portion 11a and are separated from each other by a predetermined distance. The magnetic pole tooth part 11 has a shape in which two L-shaped parts are connected in a side view. The magnetic pole tooth part 12 includes two rectangular plate-like tooth portions 12b that rise vertically from both ends of the rectangular plate-like substrate portion 12a. The magnetic pole tooth part 12 is U-shaped in a side view. The tooth part 11b and the tooth part 12b have substantially the same shape.

The auxiliary pole tooth part 13 includes a rectangular plate (cuboid) auxiliary pole tooth portion 13b that rises vertically from one end of a rectangular plate-like substrate portion 13a. The auxiliary pole tooth part 13 is L-shaped in a side view. The supplementary tooth portion 13b has substantially the same shape as the tooth portion 11b and the tooth portion 12b.

The stator 1 is configured as follows. Eight magnetic pole tooth parts 11 are arranged side by side so that adjacent tooth portions 11b are equally spaced. The magnetic pole tooth part 12 is coupled to one end in the longitudinal direction of the coupled portion, that is, the side where the substrate portion 11a protrudes in the moving direction of the mover 2 so that the tooth portion 12b is parallel to the tooth portion 11b.

Furthermore, the stator 1 is configured by fixing the complementary pole tooth parts 13 at both ends in the length direction and coupling the tooth portions 11b and 12b. The tooth portions 11 b and 12 b and the supplemental pole tooth portion 13 b are arranged in parallel at predetermined intervals along the longitudinal direction of the stator 1, with the tip surfaces in the height direction being flush. Furthermore, a conducting wire is wound around each of the tooth portions 11b and 12b to form coils 14 and 14 corresponding to the respective portions. The thickness of the conducting wire which comprises each coil 14, and the frequency | count of winding are the same. The tooth portions 11b and 12b function as magnetic pole teeth by allowing current to flow through the wound coils 14 and 14, respectively. The magnetic pole tooth parts 11 and 12 and the auxiliary pole tooth part 13 which comprise the stator 1 are formed with a non-oriented electrical steel plate, for example. By having the auxiliary pole teeth 13b that do not wind the conducting wire (not form a coil) on both ends of the stator 1, the mover 2 (permanent magnets 22a and 22b of the mover 2 is not accompanied by a reduction in thrust). ) Can be increased to a region not facing the tooth portion 11b (12b) of the stator 1. This is because the magnetic flux due to the end effect is absorbed and the pullback (force opposite to the thrust) is reduced, so that the thrust is not reduced.

FIG. 3 is a perspective view showing the configuration of the mover 2. FIG. 4 is a plan view showing the configuration of the mover 2. The mover 2 includes a back yoke 21, a plurality of permanent magnets 22 a and 22 b, and two permanent magnets 23. The back yoke 21 has a rectangular plate shape that is long in the moving direction. The back yoke 21 is made of a soft magnetic metal such as rolled steel. The permanent magnets 22a and 22b have a rectangular parallelepiped shape. The permanent magnets 22a and 22b are neodymium magnets, ferrite magnets, samarium cobalt magnets, and the like.

Permanent magnets 22 a and 22 b are arranged side by side so that their longitudinal directions are in a direction intersecting with the longitudinal direction of the back yoke 21. The permanent magnets 22a and 22b are skewed, and the longitudinal direction and the short direction of the back yoke 21 have an angle of about 3 degrees. In the arrangement of the permanent magnets 22a and 22b, the permanent magnets 22a and 22b are alternately arranged like the permanent magnets 22a, 22b, 22a, 22b,. The permanent magnets 22a and 22b are magnets having the same specifications, but are fixed to the back yoke 21 so that the magnetization directions are opposite to each other. The permanent magnet 22a has a magnetization direction that is a normal direction of the fixed surface of the back yoke 21 and is directed toward the fixed surface. The permanent magnet 22b has a direction of magnetization that is normal to the fixed surface of the back yoke 21 and is away from the fixed surface. In addition, since the magnetization directions of the permanent magnets 22a and 22b only need to be opposite to each other, they may be opposite to the above directions.

In the permanent magnet of the present embodiment, the two permanent magnets 23 have a shape obtained by dividing the permanent magnet 22b into two. The two permanent magnets 23 have the same shape. The permanent magnet 23 has a right-angled trapezoidal shape in plan view, and is tapered in the longitudinal direction. When the width in the juxtaposed direction of the permanent magnets 22a and 22b is W0, one width W1 in the juxtaposed direction of the permanent magnet 23 is W1 = 3/4 × W0, and the other width W2 is W2 = 1/4. × W0. That is, the width W1: width W2 is 3: 1. One permanent magnet 23 is provided at each end of the magnet array composed of the permanent magnets 22a and 22b in the juxtaposed direction. The two permanent magnets 23 are arranged so that the wide part and the narrow part are symmetrical to each other. That is, in FIG. 4, the permanent magnet 23 arranged on the right side of the paper surface is wide on the lower side of the paper surface and narrow on the upper side of the paper surface. On the other hand, the permanent magnet 23 arranged on the left side of the paper is narrow on the lower side of the paper and wide on the upper side of the paper. The permanent magnets 22a, 22b and 23 are fixed to the back yoke 21 with an adhesive, for example, an epoxy adhesive. Note that setting the width W1: width W2 to 3: 1 is an example, and the present invention is not limited to this. In another aspect, the ratio of the width W1: W2 is 1,2,3,4,5,6,7,8,9,10, where the ratio of the width W2 is 1. It may be in the range of any two of these numbers. The permanent magnet 23 may have a triangular shape in plan view instead of a trapezoid.

The linear motor 100 is configured by combining the stator 1 and the mover 2 configured as described above. FIG. 5 is a side view of the linear motor 100. The mover 2 faces the stator 1 such that the permanent magnets 22a and 22b face the tip surfaces of the teeth 11b and 12b of the stator 1 through a predetermined gap. Seven pairs of permanent magnets 22a (22b) included in the mover 2 are opposed to six pairs of tooth portions 11b (12b) included in the stator 1. That is, the linear motor 100 has a 7-pole 6-slot configuration. The mover 2 is theoretically configured with two sets of seven permanent magnets 22 a (22 b), but here, one of the permanent magnets 22 b is divided into two permanent magnets 23.

When a three-phase alternating current is applied to the coil 14 of the stator 1 to generate a magnetic field in the tooth portion 11b (12b), the permanent magnets 22a and 22b of the mover 2 sequentially repel magnetic attraction against this magnetic field, thereby moving the mover. 2 performs a linear motion with respect to the stator 1.

Next, the detent force of the linear motor 100 will be described. FIG. 6 is a graph showing the detent force of the linear motor 100. The horizontal axis is electrical angle and the unit is degree. The vertical axis represents the detent force and the unit is N (Newton). In the graph shown in FIG. 6, only the component of the detent force in the movable direction is shown. A positive detent force indicates a case where the detent force works in the moving direction. A negative detent force indicates a case where the detent force acts in the direction opposite to the moving direction.

Graph 61 shows the detent force when the mover 2 has a conventional configuration. The mover 2 having a conventional configuration refers to the mover 2 in which two permanent magnets 23 are provided as one magnet. A graph 62 shows the detent force when the mover 2 of the present embodiment is used. As shown in FIG. 6, when the mover 2 of the present embodiment is used, the detent force is reduced to about 63% compared to the conventional case.

This embodiment has the following effects. Since the permanent magnets 23 obtained by dividing the permanent magnet 22b constituting the mover 2 into two are arranged symmetrically at both ends of the magnet row, the detent force can be reduced. Moreover, since the permanent magnet 22b which comprises one pole is divided into two and used as the permanent magnet 23, there exists an advantage that the characteristic of the linear motor 100 does not change a lot. Furthermore, since the amount of permanent magnets used for the mover 2 does not vary, there is an advantage that the material cost does not increase.

In the above description, the tooth portion 11b of the magnetic pole tooth part 11, the tooth portion 12b of the magnetic pole tooth part 12, and the auxiliary pole tooth portion 13b of the auxiliary pole tooth part 13 are rectangular plates. A reverse taper shape may be provided at the tip. FIG. 7 is an explanatory diagram showing another configuration of the stator 1 excluding the coil 14. The top tips in the height direction of the tooth portions 11b and 12b have a reverse taper shape that is thicker than the root portions of the substrate portions 11a and 12a, respectively. Similarly, the upper end in the height direction of the auxiliary pole tooth portion 13b has a reverse taper shape that is thicker than the root portion of the substrate portion 13a.

If the upper tips in the height direction of the tooth portions 11b and 12b and the auxiliary pole tooth portion 13b are formed in a reverse taper shape, the transmission efficiency of magnetic flux can be further improved.

In the above embodiment, the armature is the stator 1 and the field part is the mover 2. However, the armature may be the mover and the field part may be the stator.

The present invention is not limited to the embodiments described above, but includes all changes and modifications that do not depart from the technical scope or essence of the present invention defined by the claims. .

DESCRIPTION OF SYMBOLS 100 Linear motor 1 Stator 11 Magnetic pole tooth part 11a Substrate part 11b Teeth part 12 Magnetic pole tooth part 12a Substrate part 12b Teeth part 13 Polarization tooth part 13a Substrate part 13b Supplementary tooth part 14 Coil 2 Movable element 21 Back yoke 22a Permanent magnet 22b Permanent magnet 23 Permanent magnet

Claims (9)

A field section for a linear motor,
A rectangular plate-shaped back yoke;
A plurality of first permanent magnets having a rectangular shape in plan view and arranged in parallel with the back yoke so that the magnetic poles are in opposite directions;
It has a polygonal shape in plan view, the width in the juxtaposed direction is tapered from one side to the other along the direction intersecting the juxtaposed direction, and at both ends in the juxtaposed direction of the plurality of first permanent magnets Two second permanent magnets having the same shape and arranged with the taper directions reversed from each other;
A field section for a linear motor. The field part for a linear motor according to claim 1, wherein the sum of the width dimensions of both ends of the second permanent magnets in the juxtaposed direction is substantially the same as the width dimension of the first permanent magnets in the juxtaposed direction. 3. The linear motor field according to claim 1, wherein a width dimension of both ends of the second permanent magnets in the juxtaposed direction has a ratio of one to the other in a range of 10: 1 to 1: 1. Department. The field part for linear motors according to any one of claims 1 to 3, wherein the second permanent magnet has a trapezoidal shape in plan view. The field part for a linear motor according to claim 1, wherein the second permanent magnet has a substantially triangular shape in plan view. The linear motor according to any one of claims 1 to 5, wherein the two second permanent magnets are arranged so as to be point-symmetric with each other in plan view with a predetermined point of the back yoke as a center. Field magnet part. The armature which has a rectangular-plate-shaped board | substrate part and the some magnetic pole tooth which wound the coil currently arranged in parallel with this board | substrate part, The linear motor as described in any one of Claims 1-6 A linear motor with a field magnet. The armature includes auxiliary teeth that are provided at intervals from the magnetic pole teeth at the end in the parallel arrangement direction of the substrate portions and do not wind a coil.
The auxiliary teeth and magnetic pole teeth have their tip portions larger than the root portions,
The linear motor according to claim 7, wherein the auxiliary teeth and the magnetic pole teeth adjacent to the auxiliary teeth face each other in the juxtaposition direction. The linear motor according to claim 7, wherein the armature is a stator, and the linear motor field portion is a mover.

Images