JP6345355B1 - Linear motor - Google Patents

Abstract

A pair of movers (2) having a core (21) having a plurality of tooth portions (23) and a winding (24) wound around the tooth portions (23), and a magnetic body ( 31) and a stator (301) in which permanent magnets (32) are alternately arranged, and the pair of movers (2) are arranged to face each other with the stator (301) interposed therebetween, and the pair of movers A gap G is provided between the stator (2) and the stator (301), and the pair of movable elements (2) are arranged in plane symmetry via the stator (301), or One of the pair of movers (2) with an axis extending through the centroid of the cross section of the stator (301) perpendicular to the moving direction of the mover (2) and extending in the moving direction of the pair of movers (2) as a rotation axis Is arranged so as to overlap the other centroid when the centroid is rotated 180 degrees, and the permanent magnet (32) is a pair of movers Is magnetized in the traveling direction of the two), magnetized surface of the adjacent permanent magnets (32) are oppositely arranged with a predetermined interval such that identical poles face each other.

Description

  TECHNICAL FIELD The present invention relates to a linear motor used for table feeding or cargo transportation of an industrial machine.

  2. Description of the Related Art Conventionally, there is a demand for speeding up and high-precision positioning for an actuator of a machine tool table feed or a transport machine. In order to meet this demand, linear motors are increasingly used for actuators of machines such as machine tools and semiconductor manufacturing apparatuses. In addition, linear motors are direct-driven, enabling higher speeds, higher accelerations, and higher-accuracy positioning than drive systems that convert rotational motion into linear motion, such as a combination of a rotary servo motor and ball screw. It is.

  In order to increase the speed and acceleration of the linear motor, it is necessary to reduce the weight and increase the thrust of the linear motor, and Patent Document 1 proposes a linear motor that is reduced in weight and increased in thrust. .

JP 2013-176269 A

  However, in the linear motor disclosed in Patent Document 1, the pair of stators arranged opposite to each other with the mover interposed therebetween is different in position along the traveling direction, and the teeth of the mover do not face each other. On the magnetic pole surface, the operating point of the permanent magnet decreases due to magnetic saturation, or magnetic flux leaks, so that the magnetic flux cannot be effectively used. Further, there is a problem in that a phase difference occurs in the induced voltage generated in the windings of the same phase due to the difference in the positions of the pair of opposing stators, and the induced voltage is reduced and the loss is increased.

  The present invention has been made in view of the above, and an object of the present invention is to obtain a linear motor in which thrust characteristics are improved by effectively using magnetic flux generated from a stator and increasing an induced voltage.

  In order to solve the above-described problems and achieve the object, the present invention is constituted by a pair of movers having a core having a plurality of tooth portions and a winding wound around the tooth portions, and a laminated structure. A magnetic body and a permanent magnet are provided with a stator in which the pair of movers are alternately arranged in the traveling direction. The pair of movers are arranged to face each other with the stator interposed therebetween, and a gap is provided between the pair of movers and the stator. In the pair of movers, one and the other of the pair of movers are arranged in plane symmetry via the stator, or pass through the centroid of the cross section of the stator perpendicular to the traveling direction of the pair of movers. When the centroid of the pair of movers is rotated 180 degrees with the axis extending in the traveling direction of the pair of movers as the rotation axis, the centroids of the pair of movers are arranged so as to overlap with each other. . The permanent magnets are magnetized in the traveling direction of the pair of movers, and the magnetized surfaces of the adjacent permanent magnets are arranged to face each other with a certain interval so that the same poles face each other.

  The linear motor according to the present invention has the effect that the magnetic flux generated from the stator can be effectively used and the induced voltage can be increased to improve the thrust characteristics.

1 is a perspective view of a linear motor according to Embodiment 1 of the present invention. Sectional drawing perpendicular | vertical to the advancing direction of the needle | mover of the linear motor which concerns on Embodiment 1. FIG. Sectional drawing perpendicular | vertical to the lamination direction of the linear motor which concerns on Embodiment 1. FIG. The figure which shows the gap magnetic flux density waveform which generate | occur | produces in the one side of the stator of the linear motor which concerns on Embodiment 1. FIG. The figure which shows the result of carrying out the series expansion | deployment of the air gap magnetic flux density waveform of the linear motor which concerns on Embodiment 1. FIG. The figure which shows the relationship between ratio Hm / τp of the permanent magnet width Hm in the advancing direction of the needle | mover of the linear motor which concerns on Embodiment 1, and the space | interval τp of a permanent magnet, and an induced voltage. Sectional drawing perpendicular | vertical to the lamination direction of the linear motor which concerns on Embodiment 2 of this invention 11 shows a relationship between an induced voltage and a ratio W / Hm between a width Hm of a permanent magnet in the moving direction of the mover of the linear motor according to the second embodiment and a dimension W of a ridge of the magnetic material in the moving direction of the mover. Figure Sectional drawing perpendicular | vertical to the lamination direction of the linear motor which concerns on Embodiment 3 of this invention. The figure which looked at the stator of the linear motor which concerns on Embodiment 3 from the space | gap direction Sectional drawing perpendicular | vertical to the lamination direction of the linear motor which concerns on the modification of Embodiment 3. FIG. Sectional drawing perpendicular | vertical to the lamination direction of the linear motor based on Embodiment 4 of this invention The figure which looked at the stator of the linear motor which concerns on Embodiment 4 from the space | gap direction Sectional drawing perpendicular | vertical to the lamination direction of the linear motor based on Embodiment 5 of this invention The figure which looked at the stator of the linear motor which concerns on Embodiment 5 from the space | gap direction

  Below, the linear motor which concerns on embodiment of this invention is demonstrated in detail based on drawing. Note that the present invention is not limited to the embodiments.

Embodiment 1 FIG.
FIG. 1 is a perspective view of a linear motor according to Embodiment 1 of the present invention. FIG. 2 is a cross-sectional view perpendicular to the traveling direction of the mover of the linear motor according to the first embodiment. FIG. 3 is a cross-sectional view perpendicular to the stacking direction of the linear motor according to the first embodiment. In FIG. 1, only some components of the mover 2 and the stator 301 are illustrated in order to facilitate understanding of the configuration. In FIG. 3, hatching of the permanent magnet 32 is omitted for easy viewing of the drawing. As shown in FIGS. 1, 2, and 3, the linear motor 101 according to the first embodiment includes a mover 2 and a stator 301. As shown in FIG. 2, the mover 2 includes a fastening plate 25 to which the mover 2 is fixed, a top plate 41 that supports the fastening plate 25, a slider 42 installed on the top plate 41, and a mover having a W-shaped cross section. It is supported by the yoke 33. Here, the shapes of the fastening plate 25, the top plate 41, the slider 42, and the mover yoke 33 are not limited to the shapes shown in FIG. 2 and can be any shape as long as the mover 2 can be supported. Good. A pair of the movers 2 are arranged so as to face the stator 301 with a gap G having a certain size, and are movable relative to the stator 301 in the traveling direction A.

The mover 2 has a core 21 having a laminated structure made of a magnetic material such as a laminated iron core or yoke of an electromagnetic steel plate. The core 21 includes a core back 22 and tooth portions 23 protruding from the core back 22 along a direction orthogonal to both the traveling direction A and the stacking direction B. Moreover, the needle | mover 2 has the coil | winding 24 wound by the tooth | gear part 23 via the insulating members, such as an insulator which is not shown in figure. The pair of movers 2 is configured such that one of the pair of movers 2 and the other of the pair of movers 2 are plane-symmetrical via the stator 301, that is, one of the pair of movers 2 and the pair of movers 2. The other is disposed at a position that is a mirror image of the stator 3 with respect to the symmetry plane. Alternatively, the pair of movable elements 2 is a pair of movable elements having an axis extending through the centroid O of the cross section of the stator 3 perpendicular to the traveling direction of the pair of movable elements 2 and extending in the traveling direction of the pair of movable elements 2 as a rotation axis. When _one centroid P ₁ of the child 2 is rotated 180 degrees, the other centroid P _{2 of the} pair of movers 2 is disposed so as to overlap. Therefore, in the pair of movers 2 arranged to face each other via the stator 301, the windings 24 wound around the tooth portions 23 at the same position in the traveling direction A are arranged in phase.

  In FIG. 1, FIG. 2 and FIG. 3, the core 21 of the mover 2 is composed of a plurality of core backs 22 and tooth portions 23. However, the core 21 may not be divided and may have an integral structure. .

  The stator 301 includes a magnetic body 31 configured by a laminated structure of laminated iron cores or yokes of electromagnetic steel plates, and a permanent magnet 32. The magnetic bodies 31 and the permanent magnets 32 are alternately arranged. The permanent magnet 32 is magnetized in the traveling direction A. The permanent magnets 32 adjacent via the magnetic body 31 are arranged at a certain interval so that the same poles face each other. Here, in the linear motor 101 shown in FIGS. 1, 2, and 3, the number of the tooth portions 23 of the mover 2 is 6, and the magnetic body 31 of the stator 301 that faces the mover 2. Although the number is 7, it may be other than this combination. Further, there is no problem in the characteristics even if the shapes of the movable element 2 and the stator 301 are reversed from the relationship between the movable element and the fixed element.

  Next, the effect of improving the induced voltage will be described using analysis results of electromagnetic field analysis. Here, the permanent magnet constituting the stator is magnetized in the gap direction perpendicular to both the moving direction and the stacking direction of the mover, and the permanent magnet is movable so as to have a different polarity from the adjacent permanent magnet. A linear motor that is bonded to a magnetic body at a constant interval in the traveling direction of the child is used as a comparative example. In the linear motor according to the comparative example, the waveform of the gap magnetic flux density generated in the gap by the stator is a waveform close to a so-called rectangular wave. When a rectangular wave is represented by f (x), the following equation (1) is obtained when series expansion is performed.

  In general, the primary component of the induced voltage that contributes to the thrust of the linear motor is proportional to the primary component of the air gap magnetic flux density. Therefore, in order to improve the motor characteristics, the primary component of the air gap magnetic flux generated from the stator is changed. Need to increase. Although it is possible to increase the primary component of the air gap magnetic flux density by increasing the amount of magnet used, the increase in the amount of magnet used increases the cost. In order to increase the primary component of the magnetic flux density generated from the stator of a linear motor with the same amount of magnet usage and the same total magnetic flux, it is necessary to convert other higher order components into primary components to make a sine wave. Ideal, but difficult in practice. Therefore, in order to improve the primary component of the magnetic flux density generated from the stator, it is necessary to reduce other high-order components and increase the primary components.

  One method of increasing the primary component by reducing the higher order component is to make the air gap density waveform a triangular wave. When a triangular wave is represented by g (x), the following equation (2) is obtained when series expansion is performed, and higher-order components can be reduced and primary components can be increased compared to rectangular waves.

  In order to make the air gap density waveform a triangular wave, it is necessary to make the surface of the air gap G generating a magnetic flux narrow as a mover while maintaining the same amount of magnetic flux.

  Further, in a linear motor in which the mover is not disposed opposite to the stator and the mover is disposed only on one side of the stator, the magnetic flux generated from the stator is a magnetic material. About 2/3 of the width of the permanent magnet in the direction orthogonal to both the moving direction and the stacking direction of the mover is linked to the side where the mover is arranged, but the mover is arranged for about 1/3. Leak to those who are not. Therefore, a linear motor in which the mover is not opposed to the stator is unable to effectively use the magnetic flux.

  In the linear motor 101 according to the first embodiment, since the mover 2 is disposed to face the stator 301, the magnetic flux generated in the gap G from the stator 301 is effectively used on both sides of the stator 301. be able to. FIG. 4 is a diagram showing a gap magnetic flux density waveform generated on one side of the stator of the linear motor according to the first embodiment. In FIG. 4, the linear motor according to the comparative example is normalized so that the maximum value of the gap magnetic flux density waveform is 1.

  As shown in FIG. 4, the air gap magnetic flux density waveform of the linear motor 101 according to the first embodiment indicated by a solid line in the figure is a triangular wave compared to the air gap magnetic flux density waveform of the linear motor according to the comparative example indicated by the broken line in the figure. It becomes a shape close to. FIG. 5 is a diagram showing the result of series expansion of the air gap magnetic flux density waveform of the linear motor according to the first embodiment. FIG. 5 is normalized so that the primary component of the air gap magnetic flux density waveform of the linear motor according to the comparative example is 1. As shown in FIG. 5, the linear motor 101 according to the first embodiment can increase the primary component by 10% or more in comparison with the linear motor according to the comparative example. Therefore, in the linear motor 101 according to the first embodiment in which the mover 2 that is a magnetic body is arranged on both sides of the stator 301, the induced voltage generated when the dimension H in the stacking direction B is the same is compared with the comparative example. It becomes 2.2 times or more of the linear motor concerned. For this reason, the linear motor 101 according to the first embodiment can have the dimension H in the stacking direction B less than or equal to half that of the linear motor according to the comparative example. Can be realized. Furthermore, according to the linear motor 101 according to the first embodiment, the core 21 of the mover 2 is disposed to face the stator 301 via the stator 301, and the mover 2 is connected by the fastening plate 25. Since the magnetic attractive force applied to the core 21 of the child 2 is offset or reduced and the load applied to the slider 42 is reduced, the life of the slider 42 can be extended.

  FIG. 6 is a diagram showing the relationship between the induced voltage and the ratio Hm / τp between the permanent magnet width Hm and the permanent magnet interval τp in the traveling direction of the mover of the linear motor according to the first embodiment. Here, the induced voltage in FIG. 6 is a value normalized by setting the induced voltage of the linear motor according to the comparative example to 1. As shown in FIG. 6, by setting Hm / τp to 0.18 <Hm / τp <0.9, an induced voltage equal to or higher than that of the linear motor according to the comparative example can be obtained. The reason why Hm / τp <0.9 is that when the width Hm of the permanent magnet 32 is increased, the width of the magnetic body 31 in the traveling direction A of the mover 2 is reduced, the magnetic body 31 is magnetically saturated, and the permanent magnet 32. This is because the operating point of is lowered. Further, 0.18 <Hm / τp is set so that if the width Hm of the permanent magnet 32 becomes too narrow, the gap surface on the gap G side of the magnetic body 31 becomes wide, and the rectangular shape is the same as in the linear motor according to the comparative example. This is because a wavy gap magnetic flux density waveform is obtained.

Embodiment 2. FIG.
FIG. 7 is a cross-sectional view perpendicular to the stacking direction of the linear motor according to Embodiment 2 of the present invention. In FIG. 7, hatching of the permanent magnet 32 is omitted for easy viewing of the drawing. In FIG. 7, the same reference numerals are assigned to the same components as those of the linear motor 101 according to the first embodiment. In FIG. 7, the linear motor 104 according to the second embodiment is similar to the linear motor according to the first embodiment in that the magnetic body 31 constituting the stator 303 has a flange 311 that holds the permanent magnet 32. Different from the motor 101. In addition, the dimension in the advancing direction A of the needle | mover 2 of the collar 311 which the magnetic body 31 has is set to W. FIG. A gap 37 is formed between the flanges 311 along the traveling direction A of the mover 2 and there is a gap.

  In the linear motor 101 according to the first embodiment, the positions of the magnetic pole surface located on the gap G side of the magnetic body 31 constituting the stator 301 and the surface on the gap G side of the permanent magnet 32 are the same. Therefore, the permanent magnet 32 is fixed to the magnetic body 31 by a method such as bonding. However, when the bonding strength is low, the permanent magnet 32 may be displaced to the gap G side and fall off. When the permanent magnet 32 is displaced to the gap G side or falls off, the permanent magnet 32 may come into contact with the mover 2, possibly causing damage to the mover 2 or damage to the permanent magnet 32. On the other hand, the linear motor 104 according to the second embodiment prevents the permanent magnet 32 from being displaced and dropped off by forming the flange 311 on the magnetic pole surface on the gap G side of the magnetic body 31 of the stator 303. It becomes possible to do.

  Further, the ridge 311 of the magnetic body 31 also has an effect of improving the induced voltage. FIG. 8 shows the ratio W / Hm between the width Hm of the permanent magnet in the moving direction of the mover of the linear motor according to the second embodiment and the dimension W of the flange of the magnetic material in the moving direction of the mover, and the induced voltage. It is a figure which shows the relationship. The solid line in FIG. 8 indicates the width Hm of the permanent magnet 32 in the traveling direction A of the mover 2 of the linear motor 104 according to the second embodiment and the dimension W of the flange 311 of the magnetic body 31 in the traveling direction A of the mover 2. The relationship between the ratio W / Hm and the induced voltage is shown. 8 indicate the width Hm of the permanent magnet 32 in the traveling direction A of the mover 2 of the linear motor 101 according to the first embodiment, and the dimension W of the magnetic body 31 in the traveling direction A of the mover 2. The relationship between the ratio W / Hm and the induced voltage is shown. As shown in FIG. 8, by setting 0 ≦ W / Hm ≦ 0.15, the induced voltage can be equal to or higher than that of the linear motor 101 according to the first embodiment.

Embodiment 3 FIG.
FIG. 9 is a cross-sectional view perpendicular to the stacking direction of the linear motor according to Embodiment 3 of the present invention. FIG. 10 is a view of the stator of the linear motor according to the third embodiment as viewed from the gap direction. In FIG. 9, hatching of the permanent magnet 32 is omitted for easy viewing of the drawing. 9 and 10, the same reference numerals are assigned to the same components as those of the linear motor 104 according to the second embodiment. 9 and 10, the linear motor 105 according to the third embodiment is implemented in that a through hole 34 is provided in the magnetic body 31 constituting the stator 304 and a mounting base 35 is provided. This is different from the linear motor 104 according to the second embodiment. The mounting base 35 is provided with a screw hole 50, and in the linear motor 105 according to the third embodiment, the magnetic body 31 is fastened to the mounting base 35 using a bolt 60.

  In the linear motor 105 according to the third embodiment, the magnetic body 31 can be fixed to the mounting base 35 with the bolts 60 of the stator 304. Thereby, it is possible to fix the magnetic body 31 constituting the divided stator 304, and to ensure the strength. In particular, when the magnetic body 31 is composed of a laminated steel plate such as an electromagnetic steel plate, it is difficult to ensure the strength by adhesion or caulking. Therefore, the strength of the magnetic body 31 is secured by fixing it to the mounting base 35 with the bolt 60. Securement and fixation are possible at the same time.

  FIG. 11 is a cross-sectional view perpendicular to the stacking direction of the linear motor according to the modification of the third embodiment. In FIG. 11, hatching of the permanent magnet 32 is omitted for easy viewing of the drawing. FIG. 11 shows a state in which two through holes 34 are arranged near the gap G side. By arranging two through holes 34 at a position close to the gap G side, the strength of the magnetic body 31 can be increased. Further, by arranging the through hole 34 on the gap G side, the magnetic flux indicated by the arrow C generated from the tip of the tooth portion 23 of the mover 2 can be shielded by the through hole 34 as shown in FIG. Thus, it is possible to suppress a decrease in thrust characteristics due to a reduction in leakage magnetic flux.

Embodiment 4 FIG.
FIG. 12 is a cross-sectional view perpendicular to the stacking direction of the linear motor according to Embodiment 4 of the present invention. FIG. 13 is a view of the stator of the linear motor according to the fourth embodiment as viewed from the air gap direction. In FIG. 12, hatching of the permanent magnet 32 is omitted for easy viewing of the drawing. 12 and 13, the same reference numerals are assigned to the same components as those of the linear motor 104 according to the second embodiment. As shown in FIGS. 12 and 13, the linear motor 106 according to the fourth embodiment includes a positioning hole 36 in the magnetic body 31 constituting the stator 305 and a mounting base 35. This is different from the linear motor 104 according to the second embodiment. A positioning pin 38 is provided on the mounting base 35.

  When the stator 305 is configured using a plurality of magnetic bodies 31, if the pitch of the magnetic bodies 31 deviates greatly from the design value, a manufacturing error occurs on the stator 305 side, and a large detent force is generated. In the linear motor 106 according to the fourth embodiment, the mounting base 35 is provided with positioning pins 38 to suppress an increase in detent force due to manufacturing errors on the stator 305 side. The magnetic body 31 is provided with a positioning hole 36. In the linear motor 106 according to the fourth embodiment, the magnetic body 31 is positioned in the stator 305 by inserting a positioning pin 38 into the positioning hole 36. As a result, the pitch intervals of the plurality of divided magnetic bodies 31 can be arranged with values close to the design values, and an increase in detent force due to manufacturing variations can be suppressed. Further, the positioning hole 36 can block the magnetic flux generated from the tip of the tooth portion 23 of the mover 2 indicated by the arrow D in FIG. 12, and can suppress the reduction of the thrust due to the leakage magnetic flux. It becomes.

Embodiment 5. FIG.
FIG. 14 is a cross-sectional view perpendicular to the stacking direction of the linear motor according to Embodiment 5 of the present invention. FIG. 15 is a view of the stator of the linear motor according to the fifth embodiment when viewed from the air gap direction. In FIG. 14, hatching of the permanent magnet 32 is omitted for easy viewing of the drawing. 14 and 15, the same reference numerals are assigned to the same components as those of the linear motor 104 according to the second embodiment. As shown in FIGS. 14 and 15, in the linear motor 107 according to the fifth embodiment, the magnetic body 31 of the stator 306 includes a connecting portion 39 connected to the adjacent magnetic body 31 at one place in the stacking direction B. This is different from the linear motor 104 according to the second embodiment.

  The linear motor 107 according to the fifth embodiment has a shape in which the stator 306 is connected in part in the stacking direction B. With such a configuration, the rigidity of the magnetic body 31 can be ensured, the pitch of the magnetic body 31 can be made close to the design value, and an increase in detent force due to manufacturing errors can be reduced. Become.

  Note that the magnetic body 31 illustrated in FIG. 15 includes the connecting portion 39 at one location in the stacking direction B, but the connecting portion 39 may be disposed at intervals in a plurality of locations in the stacking direction B.

  The configuration described in the above embodiment shows an example of the contents of the present invention, and can be combined with another known technique, and can be combined with other configurations without departing from the gist of the present invention. It is also possible to omit or change the part.

2 movers, 21 cores, 22 core backs, 23 teeth, 24 windings, 25 fastening plates, 31 magnetic bodies, 32 permanent magnets, 33 mover yokes, 34 through holes, 35 mounting bases, 36 positioning holes, 37 Gap, 38 Positioning pin, 39 Connecting part, 41 Top plate, 42 Slider, 50 Screw hole, 60 bolt, 101, 104, 105, 106, 107 Linear motor, 301, 303, 304, 305, 306 Stator, 311 .

Claims (6)

A pair of movers having a core having a plurality of teeth and a winding wound around the teeth;
A magnetic body and a permanent magnet configured in a laminated structure are alternately arranged in a traveling direction of the pair of movable elements, and
The pair of movers are arranged to face each other with the stator interposed therebetween, and a gap is provided between the pair of movers and the stator.
The pair of movers includes a cross section of the stator in which one and the other of the pair of movers are arranged in plane symmetry via the stator, or perpendicular to the traveling direction of the pair of movers The other figure of the pair of movers when the one centroid of the pair of movers is rotated 180 degrees with the axis extending through the centroid as extending in the direction of travel of the pair of movers. It is arranged so as to overlap with the heart,
The permanent magnets are magnetized in the traveling direction of the pair of movers, and the magnetized surfaces of the adjacent permanent magnets are arranged to face each other with a certain interval so that the same poles face each other.
The magnetic body has a flange that comes into contact with the permanent magnet from the gap side,
A gap is formed between the flanges along the moving direction of the mover .   The width of the permanent magnet in the traveling direction of the pair of movers is Hm and the interval between the permanent magnets is τp, and 0.18 <Hm / τp <0.9. The linear motor described. 0 ≦ W / Hm ≦ 0.15, where W is the dimension of the flange in the moving direction of the mover and Hm is the width of the permanent magnet in the moving direction of the pair of movers. The linear motor according to claim 1 or 2 . A mounting base for fixing the magnetic body;
The magnetic material, the linear motor according to any one of claims 1 to 3, characterized in that through-holes through which the bolts for fixing to the mount is provided. A mounting base for fixing the magnetic body;
The mounting base includes a positioning pin,
The magnetic material, the linear motor according to any one of claims 1 to 3, characterized in that positioning holes that engages with the positioning pin is formed. The magnetic material, a connecting portion that is connected to the adjacent magnetic material, the linear motor according to claim 1, any one of 5, characterized in that it comprises more than one place in the stacking direction.

Images