JP2014147276A - Linear motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a linear motor in which the used amount of a magnet does not increase even when the total length of a movement distance is long, and which can be operated at high speed with low power by reducing hysteresis loss.SOLUTION: In a linear motor, a movable element 1 includes rectangular plate shape permanent magnet 14 and two armature cores 12, 13 which are long along the movement direction of the movable element 1 in a vertical posture inside a coil 11. A plurality of protrusions 12a, 13a are protrudingly installed in zigzag on one surface and the other surface along the longer direction in the armature cores 12, 13. The permanent magnet 14 is arranged between the two armature cores 12, 13. The two armature cores 12, 13 are arranged so that the protrusion 12a (13a) of one armature core 12 (13) and the protrusion 13a (12a) of the other armature core 13 (12) are arranged in zigzag. The permanent magnet 14 is magnetized in the opposing direction of the two armature cores 12, 13.

Description

  The present invention relates to a linear motor formed by combining a stator and a mover having a drive coil.

  For example, in the field of manufacturing semiconductor manufacturing devices and liquid crystal display devices, there is a feeding device that can linearly move an object to be processed such as a large-area substrate at a high speed and accurately position the object at an appropriate moving position. is necessary. This type of feeding device is generally realized by converting the rotational motion of a motor as a drive source into a linear motion by a motion conversion mechanism such as a ball screw mechanism, but since a motion conversion mechanism is interposed, There is a limit to increasing the moving speed. There is also a problem that positioning accuracy is insufficient due to the presence of mechanical errors in the motion conversion mechanism.

  In order to cope with this problem, in recent years, a feeding device using a linear motor capable of directly taking out a linear motion output as a drive source has been used. The linear motor includes a linear stator and a mover that moves along the stator. In the above-described feeding device, a moving coil type linear motor (a moving coil type linear motor) in which a large number of plate-like permanent magnets are arranged in parallel at regular intervals to constitute a stator, and an armature having magnetic pole teeth and energizing coils is used as a mover. For example, Patent Document 1) is used.

JP-A-3-139160

In a moving coil type linear motor, since magnets are arranged on the stator, the amount of magnets to be used increases as the total length of the linear motor increases (the moving distance of the mover increases). In recent years, with the increase in the price of rare earths, an increase in the amount of magnets used has caused an increase in cost.
Further, when the linear motor operates, a hysteresis loss occurs due to a change in the magnetic poles of the teeth provided on the stator. Therefore, more electric power is required to operate the linear motor at high speed.

  The present invention has been made in view of the circumstances as described above, and is a linear motor that does not increase the amount of use of a magnet even when the total moving distance is long. An object of the present invention is to provide a linear motor that can operate.

  The linear motor according to the present invention is a linear motor including a stator and a mover having a coil. The stator has two plate-like portions that are long in the moving direction of the mover, and the two plate-like parts are used. The portions are provided so as to be magnetically coupled with the moving range of the mover in between, and a plurality of tooth portions are provided on one plate on each of the mutually opposing surfaces of the two plate-like portions. The toothed portion of the plate-shaped portion and the toothed portion of the other plate-shaped portion are arranged in parallel in the moving direction, and the mover is a rectangular plate that is long along the moving direction inside the coil. The magnets and the two armature cores are arranged in a vertical posture, and each of the surfaces facing the plate-like portion of each armature core has a plurality of protrusions that are magnetically coupled to the tooth portions, Protrusively arranged in a zigzag arrangement on one surface and the other surface along the longitudinal direction, Is arranged between the two armature cores, and the two armature cores are arranged so that the projections of one armature core and the projections of the other armature core are in a staggered arrangement. The magnet is magnetized in the opposite direction of the two armature cores.

  In the present invention, since the magnet is used only for the mover, the usage amount of the permanent magnet does not increase even if the total movement distance is long. Further, on each of the surfaces facing the stator of the two armature cores, a plurality of protrusions that are magnetically coupled to the teeth are arranged in a staggered manner on one surface and the other surface along the longitudinal direction. The magnets are arranged between the two armature cores, and the projections of one armature core and the projections of the other armature core are arranged in a staggered manner. Since the two armature cores are arranged and the magnet is magnetized in the opposite direction of the two armature cores, the change in the magnetic pole of the tooth portion during the operation of the linear motor is almost from the residual value to the N pole (S pole). Or there is only a change from the N pole (S pole) to the residual value. Therefore, hysteresis loss can be reduced, and high-speed operation with low power is possible.

  The linear motor according to the present invention is characterized in that the tooth portion has a groove at a substantially central portion in the longitudinal direction.

  In the present invention, by having the groove at the substantially central portion in the longitudinal direction of the tooth portion, it is possible to reduce a region where the S pole and the N pole overlap in the central portion of the tooth portion.

  The linear motor according to the present invention is characterized in that a surface of the protruding portion facing the plate-like portion is a substantially parallelogram.

  In the present invention, since the surface of the protruding portion facing the plate-like portion is a substantially parallelogram, the detent force is reduced, and uneven thrust due to the difference in the relative positions of the stator and the mover can be reduced. It becomes possible.

  The linear motor according to the present invention is characterized in that the protrusion includes a protrusion having a length different from that of the other protrusion in the moving direction.

  In the present invention, the detent force can be reduced by having the protrusions having different lengths in the moving direction of the mover.

  The linear motor according to the present invention is characterized in that the short side section of the tooth portion is inclined with respect to the moving direction of the mover.

  In the present invention, the short side of the cross section of the tooth portion is inclined with respect to the moving direction of the mover. That is, since the tooth portions are arranged in a skew manner, the detent force is reduced, and it becomes possible to reduce the thrust unevenness due to the difference in the relative positions of the stator and the mover.

  The linear motor according to the present invention is characterized in that the inclined direction of the short side of the cross section is reversed between the tooth portion of the one plate-like portion and the tooth portion of the other plate-like portion.

  In the present invention, the positional relationship between both ends in the longitudinal direction is reversed between the tooth portion of one plate-like portion and the tooth portion of the other plate-like portion. That is, since the direction in which the tooth portion is inclined is different between one and the other of the plate-like portions, it is possible to suppress the twisting that occurs when the mover is inclined to the left and right with respect to the moving direction.

  In the present invention, since the magnet is used only for the mover, the amount of use of the magnet does not increase even if the total moving distance is long, and the protrusion of one armature core and the protrusion of the other armature core Since the two armature cores are arranged so that the parts are in a staggered arrangement, the magnetic pole of the stator changes only from the residual value to the N or S pole, and from the N or S pole to the residual value, Hysteresis loss is reduced and high speed operation is possible with low power.

1 is a partially broken perspective view showing an example of a schematic configuration of a linear motor according to Embodiment 1. FIG. It is a perspective view which shows an example of the shape of the armature core and permanent magnet of the linear motor which concerns on Embodiment 1. FIG. 3 is a perspective view illustrating an example of a mover of the linear motor according to Embodiment 1. FIG. 1 is a front view illustrating an example of a schematic configuration of a linear motor according to a first embodiment. 1 is a side view illustrating an example of a schematic configuration of a linear motor according to a first embodiment. 3 is an explanatory diagram illustrating a principle of thrust generation of the linear motor according to Embodiment 1. FIG. It is sectional drawing by the VII-VII line of FIG. It is sectional drawing by the VIII-VIII line of FIG. 3 is an explanatory diagram illustrating a principle of thrust generation of the linear motor according to Embodiment 1. FIG. It is sectional drawing by the XX line of FIG. It is sectional drawing by the XI-XI line of FIG. 3 is an explanatory diagram illustrating a principle of thrust generation of the linear motor according to Embodiment 1. FIG. It is sectional drawing by the XIII-XIII line | wire of FIG. It is sectional drawing by the XIV-XIV line | wire of FIG. 3 is an explanatory diagram illustrating a principle of thrust generation of the linear motor according to Embodiment 1. FIG. It is sectional drawing by the XVI-XVI line | wire of FIG. It is sectional drawing by the XVII-XVII line of FIG. It is the graph which showed the normal hysteresis curve of iron. 4 is a graph showing hysteresis curves of armature cores and teeth in the linear motor according to the first embodiment. 6 is a front view showing a configuration of a stator of a linear motor according to Embodiment 2. FIG. FIG. 6 is a perspective view illustrating a configuration of a mover of a linear motor according to a third embodiment. 6 is a plan view showing a configuration of a mover of a linear motor according to Embodiment 3. FIG. FIG. 6 is a cross-sectional view illustrating a configuration of a stator of a linear motor according to a fourth embodiment. FIG. 10 is a cross-sectional view illustrating a configuration of a stator of a linear motor according to a fifth embodiment.

Hereinafter, the present invention will be specifically described with reference to the drawings showing embodiments thereof.
Embodiment 1
FIG. 1 is a partially broken perspective view showing an example of a schematic configuration of the linear motor according to the first embodiment. The linear motor according to the present embodiment includes a mover 1 and a stator 2. The mover 1 includes a coil 11, armature cores 12 and 13, and a permanent magnet (magnet) 14.

FIG. 2 is a perspective view showing an example of the shapes of the armature cores 12 and 13 and the permanent magnet 14 of the linear motor according to the first embodiment. Each of the armature cores 12 and 13 and the permanent magnet 14 is shown in a vertical posture. Here, the vertical posture refers to a posture in which a wide surface of a plate-like object is standing so as to be a side surface. FIG. 2A shows the armature core 12. FIG. 2B shows the armature core 13. FIG. 2C shows the permanent magnet 14. The armature core 12 has a rectangular parallelepiped shape, and a rectangular parallelepiped protrusion 12 a is formed on the upper surface and the lower surface in the longitudinal direction, which are surfaces facing the stator 2. A recess 12b is formed between two adjacent protrusions 12a. The upper protrusion 12a and the lower protrusion 12a are formed so as not to face each other. A recess 12b is formed on the lower surface of the upper surface facing the protruding portion 12a. A concave portion 12b is formed on the upper surface of the lower surface facing the protruding portion 12a. In the armature core 12 shown in FIG. 2A, five protrusions 12a are formed on the upper surface and four protrusions 12a are formed on the lower surface. As shown in FIG. 2B, the armature core 13 is an inversion of the armature core 12. A rectangular parallelepiped protrusion 13a is formed on the upper surface and the lower surface in the longitudinal direction, which are surfaces facing the stator 2. A recess 13b is formed between two adjacent protrusions 13a. The protrusion 13a on the upper surface and the protrusion 13a on the lower surface are formed so as not to face each other. A recess 13b is formed at a position facing the protrusion 13a on the upper surface. In the armature core 13 shown in FIG. 2B, four protrusions 13a are formed on the upper surface and five protrusions 13a on the lower surface. The armature core 12 and the armature core 13 have substantially the same length and width. The armature core 12 and the armature core 13 have substantially the same depth. When the armature core 12 and the armature core 13 are overlapped with each other so that their centers coincide with each other, the protrusion 12a and the recess 13b and the protrusion 12b and the protrusion 13a overlap each other. 12a and 13a are formed. As shown in FIG. 2C, the permanent magnet 14 has a rectangular parallelepiped shape. Magnetized in the front side direction from the back side of the paper. The lateral dimension of the permanent magnet 14 is substantially the same as that of the armature core 12 and the armature core 13. The vertical dimension of the permanent magnet 14 is substantially the same as the distance between the bottom surface of the upper surface recess 12 b and the bottom surface of the lower surface recess 12 b formed in the armature core 12.
The number of the protrusions 12a and 13a described above is an example, and is not limited thereto. If at least one protrusion 12a, 13a is provided on each of the upper surface (lower surface) of the armature core 12 and the lower surface (upper surface) of the armature core 13, the operation is theoretically possible.

The armature cores 12 and 13 may be laminated with a soft magnetic material, for example, a silicon steel plate, or may be made of, for example, SMC (Soft Magnetic Composites) in which magnetic metal powder is hardened. By using such a member, it is possible to suppress eddy current loss, hysteresis loss, and demagnetization of the armature core material.
The permanent magnet 14 is a neodymium magnet mainly composed of neodymium (Nd), iron (Fe), and boron (B). In addition to neodymium magnets, alnico magnets, ferrite magnets, samarium cobalt magnets, and the like may be used.

  FIG. 3 is a perspective view showing an example of the mover 1 of the linear motor according to the first embodiment. A permanent magnet 14 is sandwiched and fixed between the armature core 12 and the armature core 13. The coil 11 is wound around the side surfaces of the armature cores 12 and 13 and the permanent magnet 14. The armature cores 12 and 13 and the permanent magnet 14 are arranged in a vertical posture inside the coil 11. The longitudinal direction of the armature cores 12 and 13 and the permanent magnet 14 is the moving direction of the mover 1. As described above, the protruding portions 12a of the armature core 12 and the protruding portions 13a of the armature core 13 are alternately arranged (staggered arrangement) along the longitudinal direction. In FIG. 3, the permanent magnet 14 is magnetized in the opposing direction of the two armature cores 12 and 13. In the present embodiment, the direction is from the armature core 13 toward the armature core 12. The direction of magnetization may be reversed. In that case, the flow of magnetic lines described below is reversed, and the principle of operation is the same.

Since the armature cores 12 and 13 are formed in a rectangular plate shape and have protrusions 12a and 13a on the upper and lower surfaces in the longitudinal direction, the armature cores 12 and 13 are cut out from the soft magnetic steel plate or punched out from the steel plate. It can manufacture by laminating after that.
Therefore, it is possible to reduce variations in the width dimension of the protrusions 12a and 13a and the recesses 12b and 13b in the moving direction of the mover 1 and to improve the cogging characteristics.

  FIG. 4 is a front view showing an example of a schematic configuration of the linear motor according to the first embodiment. FIG. 5 is a side view showing an example of a schematic configuration of the linear motor according to the first embodiment. In FIG. 5, the coil 11 passes through the front side of the armature core 12 and in the left-right direction on the paper surface, but the description is omitted for convenience of explanation.

  As shown in FIG. 4, the stator 2 has a substantially horizontal U-shaped cross section. As shown in FIG. 1, the stator 2 is elongated in the moving direction of the mover 1. The stator 2 includes an upper plate portion 21 (plate-like portion), a lower plate portion 22 (plate-like portion), and side plate portions 23 that connect the upper plate portion 21 and the lower plate portion 22 to each other. The side plate portion 23 plays a role of magnetically coupling the upper plate portion 21 and the lower plate portion 22. The stator 2 is formed by bending a soft magnetic metal, for example, a flat rolled steel material. Alternatively, each of the upper plate portion 21, the lower plate portion 22, and the side plate portion 23 may be formed as a soft magnetic metal plate and may be formed by welding or screwing. It is not an essential requirement for the stator 2 to be installed in the orientation shown in FIG. It can be used in any orientation that can be installed. Therefore, as shown in FIG. 4, it is not essential that the upper plate portion 21 is on the upper side, the lower plate portion 22 is on the lower side, and the side plate portion 23 is on the left and right sides. Even if the installation direction of the stator 2 is changed from the state shown in FIG. 4, the positional relationship between the stator 2 and the mover 1 does not change. That is, as the installation direction of the stator 2 is changed, the installation direction of the mover 1 is also changed. The armature cores 12 and 13 and the permanent magnets 14 described above are arranged in a vertical position inside the coil 11 when the mover 1 is arranged as shown in FIGS. 1, 3, and 4. Is shown.

  A plurality of tooth portions 21 a having a longitudinal direction orthogonal to the moving direction of the mover 1 are arranged in parallel on the upper plate portion 21 along the moving direction of the mover 1. The tooth part 21a has a substantially rectangular parallelepiped shape. The tooth portion 21 a is provided on a surface facing the lower plate portion 22 of the upper plate portion 21. The tooth portion 21 a protrudes from the upper plate portion 21 toward the lower plate portion 22. Similarly, a plurality of tooth portions 22 a are arranged on the lower plate portion 22 along the moving direction of the mover 1. The tooth part 22a has a substantially rectangular parallelepiped shape. The tooth portion 22 a is provided on a surface facing the upper plate portion 21 of the lower plate portion 22. The tooth portion 22 a protrudes from the lower plate portion 22 toward the upper plate portion 21. The tooth portions 21a and 22a are formed of a soft magnetic metal plate, such as a steel plate, and are fixed to the upper plate portion 21 and the lower plate portion 22 by welding or screwing or the like. Alternatively, the tooth portions 21a and 22a may be formed by digging grooves on both sides of the portions to be the tooth portions 21a and 22a while leaving the portions to be the tooth portions 21a and 22a of the U-shaped soft magnetic steel plate. In this way, the cost of the stator 2 can be reduced as compared with the case where the tooth portions 21a and 22a are fixed by welding or the like by welding or the like.

  As shown in FIGS. 4 and 5, it is desirable that the tooth portion 21 a of the upper plate portion 21 and the tooth portion 22 a of the lower plate portion 22 have the same shape and the same size. The interval between adjacent tooth portions 21a (pitch of the tooth portions 21a) is substantially the same as the width in the arrangement direction of the tooth portions 21a (lateral width in FIG. 5). The same applies to the pitch of the tooth portions 22a. As shown in FIG. 5, the protruding lengths of the tooth portions 21a and 22a (vertical length in FIG. 5) are longer than the pitch of the tooth portions 21a and 22a. The dimensions of the tooth portions 21a, 22a in the left-right direction in FIG. 4 are slightly larger than those obtained by adding the dimensions of the armature cores 12, 13 and the magnet 14 in the left-right direction. In this case, the air gap is virtually shortened by the fringing magnetic flux, and the magnetic flux from the magnet of the mover 1 can be efficiently passed through the stator 2. If shortened, the mover 1 is attracted to the center by the suction force, and the straightness is improved. The lengths may be the same.

  As shown in FIG. 5, the tooth portion 21 a and the tooth portion 22 a are disposed at substantially the same position with respect to the moving direction of the mover 1. The surfaces of the tooth portion 21a and the tooth portion 22a that face the movable element 1 face each other over substantially the entire surface, but only part of the surfaces may face each other. This is because thrust is generated even in such a case. However, no thrust is generated in the mover 1 if there are no opposing portions.

The width in the arrangement direction of each of the tooth portions 21a and the tooth portions 22a (lateral width in FIG. 5) is the length in the moving direction of the set of the protruding portion 12a of the armature core 12 of the mover 1 and the protruding portion 13a of the armature core 13. It is shorter than (lateral width in FIG. 5).
The width in the arrangement direction of each of the tooth portions 21a and the tooth portions 22a may be the same as or longer than the width in the moving direction of the protrusions 12a and 13a. What is necessary is just to set suitably in consideration of the dimension, thrust characteristic, etc. of a linear motor.

  FIG. 6 is an explanatory diagram illustrating the principle of thrust generation of the linear motor according to the first embodiment. 7 is a cross-sectional view taken along line VII-VII in FIG. 8 is a cross-sectional view taken along line VIII-VIII in FIG. FIG. 6 is a view when viewed from the opening side of the stator 2 (side surface of the linear motor). The left side of each of FIGS. 7 and 8 shows the front side of the page of FIG. In FIG. 6, the coil 11 passes through the front side of the armature core 12 and in the left-right direction on the paper surface, but the description is omitted for convenience of explanation. An alternating current is passed through the coil 11 of the mover 1. In FIG. 6, a black circle in the circle indicates that a current flows from the back of the paper to the front. In FIG. 6, X in the circle indicates that current flows from the front to the back of the page. When energized in the direction shown by the coil 11 in FIG. 6, when the mover 1 is outside the stator 2 (the energized mover 1 is a single unit), the coil 11 causes the armature cores 12 and 13 to be placed on the upper side. The N pole and the S pole are excited on the lower side. However, when the mover 1 is inside the stator 2 that is a soft magnetic material, the excitation of the armature cores 12 and 13 needs to be considered in an integrated magnetic circuit including the mover 1 and the stator 2. is there.

  In FIG. 6, the magnetic poles of the teeth 21 a of the upper plate portion 21 and the magnetic poles of the protrusions 12 a of the armature core 12 are indicated by solid lines. The magnetic poles of the teeth 22a of the lower plate 22 and the magnetic poles of the protrusions 13a of the armature core 13 are indicated by dotted lines. A solid line indicates a phenomenon occurring on the front side of the movable element 1 and the stator 2. A dotted line indicates a phenomenon occurring on the back side of the movable element 1 and the stator 2.

  When the coil 11 is energized in the direction shown in FIGS. 7 and 8, both the armature cores 12 and 13 tend to be excited to the N pole on the upper side and to the S pole on the lower side. However, in the cross section shown in FIG. 7, there are no teeth 21 a and 22 a on the upper side and the lower side of the armature cores 12 and 13. Therefore, there is no flow of magnetic field lines that the entire armature cores 12 and 13 are uniformly excited to the N pole on the upper side and the S pole on the lower side. In the cross section shown in FIG. 8, the lines of magnetic force flow along the path of the armature core 13 → the permanent magnet 14 → the armature core 12. This is because the magnetic field lines try to pass through the path having the smallest magnetic resistance as the magnetic circuit. Air has a larger magnetic resistance than a magnetic material, and the longer the distance, the greater the magnetic resistance. Therefore, the magnetic lines of force do not enter and exit at the projection 12a of the armature core 12 and the projection 13a of the armature core 13 that are not opposed to the tooth portions 21a and 22a. As shown in FIG. 8, magnetic force lines flow from the tooth part 22a to the protruding part 13a of the armature core 13 facing the tooth part 22a, and magnetic lines of force flow from the protruding part 12a of the armature 12 facing the tooth part 21a to the tooth part 21a. It becomes. As a result, the front side (opening side) of the upper tooth portion 21a in FIG. 8 is excited to the S pole, and the back side (side plate portion 23 side) of the lower tooth portion 22a is excited to the N pole. The same applies to the other tooth portions 21a and 22a. In FIG. 7, the tooth portions 21a and 22a visible on the back side of the cross section are not shown. This is in order not to obstruct understanding of the above description. Originally, the tooth portions 21a and 22a facing the protrusions 12a and 13a that are visible on the back side of the cross section in FIG. 7 should be described.

  6, 7, and 8, the excitation of the armature cores 12 and 13 by energizing the coil 11 has been described. Next, the armature by the magnet 14 sandwiched between the armature cores 12 and 13 is described. The principles of excitation of the cores 12 and 13 and the thrust generation principle of the linear motor will be described. FIG. 9 is an explanatory diagram showing the principle of thrust generation of the linear motor according to the first embodiment. 10 is a cross-sectional view taken along line XX of FIG. 11 is a cross-sectional view taken along line XI-XI in FIG. In FIG. 9, the coil 11 passes through the front side of the armature core 12 and in the left-right direction on the paper surface, but the description is omitted for convenience of explanation. As shown in FIGS. 10 and 11, the magnetization direction of the permanent magnet 14 is from the right side to the left side of the drawing (in FIG. 9, from the back side to the front side). Accordingly, the left armature core 13 of the permanent magnet 14 is excited to the N pole, and the right armature core 12 is excited to the S pole. In the cross section shown in FIG. 10, there are no teeth 22 a and 21 a on the lower side of the armature core 12 and the upper side of the armature core 13. Therefore, the armature cores 12 and 13 hardly attract the teeth 22a and 21a. In contrast, in the cross section shown in FIG. 11, the armature core 12 and the tooth portion 21a are sucked. The armature core 13 and the tooth portion 22a are sucked. In FIG. 9, the armature core 12 on the near side is excited to the N pole, and the armature core 13 on the back side is excited to the S pole. Therefore, the armature core 12 on the near side sucks with the upper tooth portion 21a, the armature core 13 on the back side sucks with the lower tooth portion 22a, and the mover 1 moves to the left side of the drawing. In FIG. 10, as in FIG. 7, the tooth portions 21 a and 22 a that are visible on the back side of the cross section are omitted.

  FIG. 12 is an explanatory diagram illustrating the principle of thrust generation of the linear motor according to the first embodiment. FIG. 12 is a view showing a state in which the mover 1 has moved to the left side from the state of FIG. 13 is a cross-sectional view taken along line XIII-XIII in FIG. 14 is a cross-sectional view taken along line XIV-XIV in FIG. FIG. 12 is a view when seen from the opening side of the stator 2. The left side of each of FIGS. 13 and 14 shows the front side of the page of FIG. In FIG. 12, the coil 11 passes through the front side of the armature core 12 and in the left-right direction on the paper surface, but the description is omitted for convenience of explanation. The alternating current flowing through the coil 11 of the mover 1 is in the opposite direction to that in FIG. When the coil 11 is energized in the direction shown in FIG. 12, how the mover 1 and the stator 2 are excited is integrated with the mover 1 and the stator 2 as in FIG. It is necessary to consider in the magnetic circuit.

  In FIG. 12, the magnetic poles of the teeth 21 a of the upper plate portion 21 and the magnetic poles of the protrusions 13 a of the armature core 13 are indicated by dotted lines. The magnetic poles of the teeth 22a of the lower plate 22 and the magnetic poles of the protrusions 12a of the armature core 12 are indicated by solid lines. The use of solid and dotted lines is the same as in FIG. The solid line shows the phenomenon occurring on the front side. A dotted line indicates a phenomenon occurring on the back side.

  When the coil 11 is energized in the direction shown in FIGS. 12, 13, and 14, both the armature cores 12 and 13 tend to be excited to the S pole on the upper side and to the N pole on the lower side. However, in the cross section shown in FIG. 13, there are no tooth portions 21 a and 22 a on the upper side and the lower side of the armature cores 12 and 13. Therefore, there is no flow of magnetic field lines that the entire armature cores 12 and 13 are uniformly excited to the S pole on the upper side and the N pole on the lower side. In the cross section shown in FIG. 14, the magnetic lines of force flow along the path of the armature core 13 → the permanent magnet 14 → the armature core 12. This is because the magnetic field lines try to pass through the path with the least magnetic resistance as a magnetic circuit. Air has a larger magnetic resistance than a magnetic material, and the longer the distance, the greater the magnetic resistance. Therefore, the magnetic lines of force do not enter and exit at the projection 12a of the armature core 12 and the projection 13a of the armature core 13 that are not opposed to the tooth portions 21a and 22a. As shown in FIG. 14, a line of magnetic force flows from the tooth part 21a to the protruding part 13a of the armature core 13 facing it, and a line of magnetic force flows from the protruding part 12a of the armature 12 facing the tooth part 22a to the tooth part 22a. It becomes. As a result, the back side (side plate portion 23 side) of the upper tooth portion 21a in FIG. 14 is excited to the N pole, and the front side (opening side) of the lower tooth portion 22a is excited to the S pole. The same applies to the other tooth portions 21a and 22a. In FIG. 13, as in FIG. 7, the tooth portions 21a and 22a that are visible on the back side of the cross section are omitted.

  The excitation of the armature cores 12 and 13 by energizing the coil 11 has been described with reference to FIGS. 12, 13, and 14. Next, the armature by the magnet 14 sandwiched between the armature cores 12 and 13 is described. The principles of excitation of the cores 12 and 13 and the thrust generation principle of the linear motor will be described. FIG. 15 is an explanatory diagram showing the principle of thrust generation of the linear motor according to the first embodiment. 16 is a cross-sectional view taken along line XVI-XVI in FIG. 17 is a cross-sectional view taken along line XVII-XVII in FIG. In FIG. 15, the coil 11 passes through the front side of the armature core 12 and in the left-right direction on the paper surface, but the description is omitted for convenience of explanation. As shown in FIGS. 16 and 17, the magnetization direction of the permanent magnet 14 is from the right side to the left side of the drawing (in FIG. 15, from the back side to the near side). Therefore, the left armature core 12 of the permanent magnet 14 is excited to the N pole, and the right armature core 13 is excited to the S pole. In the cross section shown in FIG. 16, there are no tooth portions 21 a and 22 a on the upper side of the armature core 12 and on the lower side of the armature core 13. For this reason, the armature cores 12 and 13 hardly attract the teeth 21a and 22a. On the other hand, in the cross section shown in FIG. 17, the armature core 12 and the tooth portion 22a are sucked. The armature core 13 and the tooth portion 21a are sucked. In FIG. 15, the armature core 12 on the near side is excited to the N pole, and the armature core 13 on the back side is excited to the S pole. Therefore, the armature core 12 on the near side sucks with the lower tooth portion 22a, the armature core 13 on the back side sucks with the upper tooth portion 21a, and the mover 1 moves to the left side of the drawing. When the mover 1 moves to the left side, the state becomes similar to that shown in FIGS. By repeating the same operation in this manner, the mover 1 moves continuously.

  Here, the combination of the two types of armature cores 12 and 13 and the magnet 14 and the state of excitation by energization in the upper and lower tooth portions 21a and 22a will be considered. First, the excitation of the armature cores 12 and 13 will be considered. As shown in FIGS. 8 and 14, the projection 12a of the armature core 12 on the front side (left side in the drawing) is excited to the N pole or not excited at both the upper and lower portions. The protrusion 13a of the armature core 13 on the back side (right side of the drawing) is excited to the S pole or not excited at the upper and lower portions.

  Next, the tooth portions 21a and 22a will be considered. As shown in FIGS. 8 and 14, the back side of the tooth portion 21a and the tooth portion 22a is excited to the N pole or not excited. The front side of the tooth portion 21a and the tooth portion 22a is excited to the S pole or not excited.

When the direction of the current is changed at a constant period (an alternating current is passed), the armature cores 12 and 13 and the tooth portions 21a and 22a of the present embodiment do not change the magnetic poles like N ← → S, and the residual value ← → N or residual value ← → S That is, it does not change to the opposite pole like N to S or S to N.
Although the left side (near side) and the right side (back side) are described in the tooth portions 21a and 22a, the excitation state is not completely separated in the middle, and the center of the tooth portions 21a and 22a. In the part, it becomes an S pole or an N pole. There are so-called overlapping portions of the two magnetic poles. The left side and the right side are notations when referring to FIGS. 7, 8, 10, 11, 13, 14, 16 and 17, and the near side and the back side are notations when referring to FIGS. is there.

  Here, the hysteresis loss of the magnetic material is considered. Hysteresis loss is electrical energy lost when a magnetic material is magnetized by alternating current. It is known that the hysteresis loss is proportional to the area of the magnetic material surrounded by the hysteresis loop. Like the linear motor of the present embodiment, the poles excited by the projection 12a of the armature 12, the projection 13a of the armature core 13, and the teeth 21a and 22a are limited and do not change between N and S. By doing so, the area of the hysteresis loop can be reduced and the hysteresis loss can be reduced.

  FIG. 18 is a graph showing a normal hysteresis curve of iron. FIG. 19 is a graph showing hysteresis curves of the armature cores 12 and 13 and the tooth portions 21a and 22a in the linear motor according to the first embodiment. The horizontal axis is the strength of the magnetic field, and the unit is A / m. The vertical axis represents the magnetic flux density, and the unit is T. As is clear by comparing FIG. 18 and FIG. 19, the area of the portion surrounded by the hysteresis curve in the present embodiment shown in FIG. 19 is more than the area of the portion surrounded by the hysteresis curve shown in FIG. small. Therefore, a reduction in hysteresis loss is shown.

  The linear motor according to the first embodiment as described above has the following effects. Since the permanent magnet 14 is used only for the mover 1, the usage amount of the permanent magnet 14 does not increase even if the total length of the moving distance is long. Further, by reversing the armature cores 12 and 13 having the same shape on the mover 1 and alternately arranging them, the magnetic poles of the tooth portions 21a and 22a of the stator 2 are determined to be N poles or S poles, N poles or Since it changes only from the S pole to the residual value, the hysteresis loss is reduced, and high speed operation is possible with low power.

  As shown in FIG. 9 and the like, the magnetization direction of the magnet 14 is from the back side to the near side of the stator 2 in FIG. 9 and the like, but it may be reversed. In that case, the direction of the lines of magnetic force flowing between the armature core 12 and the armature core 13 is reversed. That is, the magnetic lines of force enter from the protrusion 12 a of the armature core 12, pass through the magnet 14, and exit from the protrusion 13 a of the armature core 13. Although the operation described above is changed by reversing the direction of the lines of magnetic force flowing between the armature core 12 and the armature core 13, the operation principle is the same.

  In the first embodiment, all of the mover 1 is sandwiched between the stators 2. However, in the present invention, the armature cores 12 and 13 and the permanent magnets 14 of the mover 1 are the stator 2. The coil 11 may protrude from the stator 2 as long as it is sandwiched between them.

  Next, the improvement of the influence by the end effect will be described. The end effect means that in a linear motor, the influence of magnetic attraction and repulsion generated at both ends of the mover affects the thrust characteristics (cogging characteristics, detent characteristics) of the motor. The end effect occurs because the magnetic flux loop flows in the same direction as the moving direction of the mover. However, in the linear motor according to the first embodiment, the loop (magnetic flux loop) including the magnetic path passing through the stator 2 body flows in a direction perpendicular to the traveling direction. It becomes possible to reduce the influence of the effect.

Embodiment 2
FIG. 20 is a front view showing the configuration of the stator 2 of the linear motor according to the second embodiment. In the second embodiment, each of the tooth portions 21a and 22a has grooves 21a1 and 22a1. As described above, the tooth portions 21a and 22a are mixed with excitation by the coil 11 and excitation by the flow of magnetic lines composed of the stator 2, the armature cores 12 and 13 and the permanent magnet 14 including the tooth portions 21a and 22a. . By these two excitations, an area where the S pole and the N pole overlap is generated near the center in the longitudinal direction of the tooth portions 21a and 22a. Since the excitation of the tooth portions 21a and 22a is weakened by the overlapping region, the overlapping region does not exist or is desirably a narrow region even if it exists. Therefore, in the second embodiment, grooves 21a1 and 22a1 are provided in the tooth portions 21a and 22a, respectively.

  The groove 21a1 is formed in the central portion in the longitudinal direction of the tooth portion 21a. The groove 21a1 is formed so as to be dug in the direction of the plate-like portion 21 from the surface facing the mover 1 of the tooth portion 21a. The groove 21a1 is formed along the direction intersecting the longitudinal direction of the tooth portion 21a. In FIG. 20, the groove 21a1 is formed along a direction perpendicular to the longitudinal direction of the tooth portion 21a, that is, the short direction. The groove 21a1 is a rectangular groove having a rectangular cross section. The depth of the groove 21a1 is shorter than the protruding length of the tooth portion 21a. In FIG. 20, the left and right teeth are connected by a connecting portion 21a2 near the bottom surface of the groove 21a1. However, the left and right sides of the tooth portion 21a may be completely separated by the groove 21a1. On the other hand, it is good also considering the shallow V-groove as the groove | channel 21a1 (22a1) to the extent which divides the surface which opposes the needle | mover 1 of the tooth | gear part 21a (22a) into right and left. In addition, since the groove | channel 22a1 and the connection part 22a2 which are formed in the tooth | gear part 22a are respectively the same as the groove | channel 21a1 and the connection part 21a2 which are formed in the tooth | gear part 21a, description is abbreviate | omitted.

  As described above, in the linear motor according to the second embodiment, in addition to the effects achieved by the linear motor according to the first embodiment, the S pole and the N pole overlap at the center of the tooth portions 21a and 22a by the grooves 21a1 and 22a1. It is possible to reduce the area to be used. Thereby, the excitation state of the tooth portions 21a and 22a is stabilized, and a stable propulsive force can be obtained. It is possible to eliminate overlapping regions by appropriately setting the depth and width of the grooves 21a1 and 22a1.

Embodiment 3
FIG. 21 is a perspective view showing the configuration of the mover 1 of the linear motor according to the third embodiment. FIG. 22 is a plan view showing the configuration of the mover 1 of the linear motor according to the third embodiment. Since the stator 2 is the same as that of the first embodiment or the second embodiment, the description thereof is omitted.

  In the third embodiment, the length of the protruding portion 12a1 of the armature core 12 in the movable direction (left and right direction in the drawing) is longer than the other protruding portions 12a. Correspondingly, the concave portion 12b1 on the opposite side (back side of the drawing) of the protruding portion 12a1 is also longer in the movable direction than the other concave portions 12b. The armature core 13 is the same as the armature core 12. The length of the recess 13b1 in the movable direction is longer than that of the other recess 13b. The length of the protrusion 13a1 (not shown) on the opposite side of the recess 13b1 in the movable direction is also longer than the other protrusions 13a.

  The protrusions 12a and 12a1 of the armature core 12 and the recesses 12b and 12b1 of the armature core 12 have a parallelogram shape whose end faces are not rectangular. Similarly, the protrusions 13a and 13a1 of the armature core 13 and the recesses 13b and 13b1 of the armature core 13 are also parallelograms whose end faces are not rectangular. Thereby, as shown in FIG. 22, the protrusions 12a, 12a1, 13a, and 13a1 are inclined with respect to the moving direction. A so-called skew arrangement is provided. The configuration as described above is a configuration for reducing the detent force.

  Since the relative permeability of the mover 1 periodically changes in the moving direction, higher-order detent force harmonic components become significant. In general, in the case of phase-independent driving, the fundamental wave and the second-order and fourth-order harmonics are canceled at the time of three-phase synthesis, but the third-order, sixth-order, and ninth-order harmonics strengthen each other. .

  Among the harmonic components, the sixth-order harmonic tends to increase in particular. Therefore, the length in the moving direction of the projection 12a1 of the armature core 12 and the projection 13a1 of the armature core 13 is set to the other projection 12a. 13a is longer by τ / 6 (τ: pole pitch, τ = λ / 2, λ: length corresponding to 360 degrees in electrical angle). As a result, the phase of the detent force generated in the protrusion 12a1 (13a1) and the protrusion 12a (13a) differs by 180 degrees in the sixth harmonic component, so the sixth harmonic component is canceled and reduced. Although the protrusion 12a1 (13a1) is made longer by τ / 6, the same effect can be obtained even if the protrusion 12a1 (13a1) is made shorter than the other protrusion 12a (13a) by τ / 6. That is, it is only necessary to provide an armature core having a length different from that of the other protrusion 12a (13a) by τ / 6.

  Next, the 12th-order or higher harmonic components can be reduced by arranging the protrusions 12a and 12a1 of the armature core 12 and the protrusions 13a and 13a1 of the armature core 13 in a skew arrangement. The skew arrangement is to form the protrusions 12a and 12a1 of the armature core 12 and the protrusions 13a and 13a1 of the armature core 13 with an inclination (angle) with respect to the vertical direction of the moving direction. The skew angle (skew angle) is about 0 to 6 degrees.

  In the above description, the lengths of the protrusions 12a and 12a1 of the armature core 12 and the lengths of the protrusions 13a and 13a1 of the armature core 13 are changed, and the skew arrangement of the protrusions 12a, 12a1, 13a, and 13a1 is changed. went. In such a configuration, the length of the armature core and the skew angle can be changed independently, so that the detent force can be effectively reduced with respect to the main harmonic component. However, the present invention is not limited to this, and only the length of the protrusion 12a1 or the like may be changed without performing the skew arrangement. Further, only the skew arrangement of the protrusions 12a and 13a may be performed without forming the protrusions 12a1 and 13a1.

  As described above, the linear motor according to the third embodiment has the effect of reducing the harmonic component of the detent force in addition to the effects exhibited by the linear motor according to the first and second embodiments.

Embodiment 4
FIG. 23 is a cross-sectional view showing the configuration of the stator 2 of the linear motor according to the fourth embodiment. FIG. 23 is a cross-sectional view of the linear motor stator 2 cut along the moving direction. The tooth portion 21a included in the upper plate portion 21 and the tooth portion 22a included in the lower plate portion 22 are arranged in a skew manner. This will be described using the third tooth portion 21a from the left in FIG. The cross section of the tooth portion 21a is rectangular. A rectangle indicated by a dotted line indicates a case where the tooth portion 21a is not skewed. In FIG. 23, the moving direction of the mover 1 is the left-right direction. When the skew is not arranged, the short side of the tooth portion 21a indicated by the dotted line is parallel to the moving direction of the mover 1. In the case of the skew arrangement, the short cross-sections E1 and E2 are inclined with respect to the moving direction of the mover 1. In FIG. 23, the tooth part 22a has an end face at the tip in the protruding direction. In the second tooth portion 22a from the left in FIG. 23, a rectangle indicated by a dotted line indicates a case where the tooth portion 22a is not skewed. The short side of the end face is parallel to the moving direction of the mover 1 and is not inclined. In the case of the skew arrangement, the short sides E3 and E4 of the end face are inclined with respect to the moving direction of the mover 1. Since the cross section of the tooth portion 22a has the same shape as the end face, the short side of the cross section is similarly inclined with respect to the moving direction of the mover 1.

The mover 1 is the same as that of any one of the first to third embodiments described above, and a description thereof will be omitted. In the fourth embodiment, the tooth portion 21a and the tooth portion 22a of the stator 2 are arranged in a skew so that the protrusion portion 12a (12a1) of the armature core 12 of the mover 1 and the protrusion portion 13a of the armature core 13 ( The detent force can be reduced without skewing 13a1).
Note that the same movable element as that of the above-described third embodiment can be used. The reduction of the detent force is related to the angle formed by the teeth 21 a and 22 a of the stator 2, the projection 12 a (12 a 1) of the armature core 12 of the mover 1, and the projection 13 a (13 a 1) of the armature core 13. . The teeth 21 a and 22 a of the stator 2, the projection 12 a (12 a 1) of the armature core 12 of the mover 1, and the projection 13 a (13 a 1) of the armature core 13 so that the angle formed is an appropriate value. Each may be skewed.

Embodiment 5
FIG. 24 is a cross-sectional view showing the configuration of the stator 2 of the linear motor according to the fifth embodiment. It is the cross-sectional view which cut | disconnected the linear motor along the moving direction. The tooth portion 21a of the upper plate portion 21 and the tooth portion 22a of the lower plate portion 22 are arranged in a skew manner. That is, the tooth part 21 a and the tooth part 22 a of the stator 2 are arranged so as to be inclined with respect to the moving direction of the mover 1. The mover 1 is the same as that of any one of the first to fourth embodiments described above, and a description thereof will be omitted.

  In the fifth embodiment, the tooth portion 21a provided in one plate-like portion 21 and the tooth portion 22a provided in the other plate-like portion 22 are reversed in the direction of inclination of the short side. As shown in FIG. 24, the short cross-sections E1 and E2 of the tooth portion 21a and the end face short sides E3 and E4 of the tooth portion 22a are inclined with respect to the moving direction of the mover 1. This is the same as in the fourth embodiment. In the fifth embodiment, the direction of inclination between the tooth portion 21a and the tooth portion 22a is reversed. In other words, the inclination directions of the short cross sections E1 and E2 of the tooth portion 21a and the short cross sections E3 and E4 of the tooth portion 22a are opposite to each other. This is intended to suppress twisting due to the skew arrangement. By arranging the tooth portions 21a and 22a in a skew manner, the thrust generated in the linear motor is generated in a direction inclined by the skew angle from the moving direction, so that the entire mover 1 may be tilted. By reversing the inclination directions of the tooth portion 21a and the tooth portion 22a, the thrust component in the direction (lateral direction) perpendicular to the moving direction generated by the tooth portion 21a and the tooth portion 22a is reversed. Therefore, the thrust components in the lateral direction cancel each other and can be prevented from being twisted.

  As described above, the fifth embodiment provides the following effects in addition to the effects of the linear motor according to the first to fourth embodiments. By arranging the tooth portion 21a and the tooth portion 22a of the stator 2 in a skewed manner, the protrusion 12a (12a1) of the armature core 12 of the mover 1 and the protrusion 13a (13a1) of the armature core 13 are not skewed. This has the effect of reducing the harmonic component of the detent force. In addition, the direction in which the tooth portion 21a and the tooth portion 22a are inclined is reversed, thereby providing an effect of preventing twisting.

  In the fifth embodiment, similarly to the fourth embodiment, the mover 1 in the third embodiment can be used, and the skew angles of the mover 1 and the stator 2 may be determined as appropriate.

Further, in this specification, the stator 2 has a shape in which a portion that becomes a tooth portion protrudes from the plate-like member, but a portion that becomes a tooth in the plate-like member, for example, forms a slit or becomes a tooth portion. The present invention can be implemented even if it is formed in a comb-tooth shape.
Furthermore, in the above description, a single-phase linear motor (unit for a single phase) has been described. However, for example, in the case of configuring a three-phase linear motor, the above-described three movers are connected to the tooth pitch. What is necessary is just to arrange | position on a straight line at intervals only x (n + 1/3) or the pitch of a tooth part x (n + 2/3) (n is an integer). In this case, an integer n may be set in consideration of the length of each movable element in the longitudinal direction.

The technical features (components) described in each embodiment can be combined with each other, and new technical features can be formed by combining them.
The embodiments disclosed herein are illustrative in all respects and should not be considered as restrictive. The scope of the present invention is defined not by the above-mentioned meaning but by the scope of the claims, and is intended to include all modifications within the meaning and scope equivalent to the scope of the claims.

DESCRIPTION OF SYMBOLS 1 Movable element 11 Coil 12 Armature core 12a, 12a1 Protrusion part 12b, 12b1 Concave part 13 Armature core 13a, 13a1 Protrusion part 13b, 13b1 Concave part 14 Permanent magnet (magnet)
2 Stator 21 Upper plate part (plate-like part)
21a tooth part 21a1 groove 21a2 connecting part 22 lower plate part (plate-like part)
22a tooth part 22a1 groove 22a2 connecting part 23 side plate part

Claims (6)

In a linear motor including a stator and a mover having a coil,
The stator has two plate-like portions that are long in the moving direction of the mover, and the two plate-like portions are provided to face each other so as to be magnetically coupled with the moving region of the mover in between. Yes,
On each of the two plate-like portions facing each other, a plurality of tooth portions are arranged in the moving direction so that the tooth portions of one plate-like portion and the tooth portions of the other plate-like portion face each other. And
The mover has a rectangular plate-shaped magnet and two armature cores arranged vertically in the coil, both along the moving direction.
A plurality of protrusions that are magnetically coupled to the tooth portions are arranged in a staggered manner on one surface and the other surface along the longitudinal direction on each surface of each armature core that faces the plate-like portion. Projecting like
The magnet is disposed between the two armature cores;
The two armature cores are arranged so that the protrusions of one armature core and the protrusions of the other armature core are in a staggered arrangement,
The linear motor, wherein the magnet is magnetized in a direction opposite to two armature cores.   The linear motor according to claim 1, wherein the tooth portion has a groove at a substantially central portion in a longitudinal direction. 3. The linear motor according to claim 1, wherein a surface of the protruding portion that faces the plate-like portion is a substantially parallelogram. 4. 4. The linear motor according to claim 1, wherein the protrusion includes a protrusion having a length different from that of the other protrusion in the moving direction. 5. The linear motor according to any one of claims 1 to 4, wherein a short side of the cross section of the tooth portion is inclined with respect to a moving direction of the mover. The linear motor according to claim 5, wherein the inclined direction of the short side of the cross section is reversed between the tooth portion of the one plate-like portion and the tooth portion of the other plate-like portion.

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