JP2014143881A - Linear motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a linear motor in which a use amount of a magnet does not increase even if total length of a moving distance is long and achieves high speed operation with low power by reducing hysteresis loss.SOLUTION: In a linear motor, a needle includes two armature cores and a magnet in rectangular plate shapes, in which a moving direction is set to be a longitudinal direction, inside a coil in a vertical posture. Projections are arranged in parallel along the longitudinal direction on faces confronted with a plate-like part of the stator of the armature core. The two armature cores sandwich the magnet, and the projection of one armature core and the projection of the other armature core are fixed to be arranged in a staggered manner. The magnet is magnetized in a direction toward the other armature core from the one armature core.

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 parts are opposed to each other with the moving range of the mover therebetween and are magnetically coupled, and a rectangular parallelepiped tooth portion is formed on one of the two plate-like parts on the mutually opposing surfaces. The tooth part of the first part and the tooth part of the other plate-like part are arranged side by side in the movement direction so that at least a part does not face each other. The rectangular plate-shaped magnet and the two armature cores are arranged in a vertical posture, and each of the surfaces of the armature core that faces the plate-like portion is provided with protrusions along the longitudinal direction. The magnet is disposed between the two armature cores, and one of the armature cores And the projection and the projecting portion of the other of the armature core have a staggered, wherein said magnet are magnetized in the opposite direction of the two armature core.

  According to the present invention, the change in the magnetic pole of the tooth portion during operation of the linear motor is only a change from the residual value to the N pole (S pole) or from the N pole (S pole) to the residual value, thereby reducing the hysteresis loss. It becomes possible to operate at high speed with low power.

  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 projecting portion facing the plate-like portion is a substantially parallelogram, the detent force is reduced and the stator and the movable member are reduced as in the case where the plurality of armature cores are skewed. It is possible to reduce thrust unevenness due to a difference in relative positions of the children.

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

  In this invention, it becomes possible to reduce detent force by having the protrusion part from which the length of the moving direction of a needle | mover differs.

  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 length of the moving distance is long, and the armature core has a long portion and a short portion in the opposing direction of the plate-like portion. Since the magnetic poles of the stator teeth change 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 with low power is possible. It becomes.

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. It is explanatory drawing which shows the thrust generation principle of a linear motor. 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 XI-XI line of FIG. It is sectional drawing by the XII-XII line | wire of FIG. It is explanatory drawing which shows the thrust generation principle of a linear motor. 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. 6 is a perspective view showing a mover of a linear motor according to Embodiment 3. FIG. 6 is a plan view showing 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. FIG. 2A shows the armature core 12. FIG. 2B shows the armature core 13. FIG. 2C shows the permanent magnet 14. As shown in FIG. 1, the armature core 12 has a rectangular plate shape whose longitudinal direction is the moving direction of the mover 1. A rectangular parallelepiped protrusion 12a (protrusion) is formed on the upper and lower surfaces of the armature core 12 in the longitudinal direction. A recess 12b is formed between two adjacent protrusions 12a. In the example shown in FIG. 2A, five protrusions 12a are formed on each of the upper surface and the lower surface. The protrusion 12a on the upper surface and the protrusion 12a on the lower surface are formed at positions facing each other. Similarly to the armature core 12, the armature core 13 has a rectangular plate shape in which the moving direction of the mover 1 is the longitudinal direction. A rectangular parallelepiped protrusion 13a (protrusion) is formed on the upper and lower surfaces of the armature core 13 in the longitudinal direction. A recess 13b is formed between two adjacent protrusions 13a. In the example shown in FIG. 2B, four protrusions 13a are formed on each of the upper surface and the lower surface. The protrusion 13a on the upper surface and the protrusion 13a on the lower surface are formed at positions facing each other. The numbers of the protrusions 12a and the protrusions 13a are merely examples, and are not limited to those shown in FIGS. 2A and 2B. It suffices if there is at least one pair of protrusions 12a and recesses 12b on the upper and lower surfaces of the armature core 12, respectively. Similarly, it is sufficient that the armature core 13 has at least one pair of protrusions 13a and recesses 13b on the upper and lower surfaces, respectively. By combining such an armature core 12, the armature core 13, and the magnet 14 and winding a coil 11 wire around the armature core 12, it is possible to form a mover having a minimum size. 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 so that their centers coincide with each other, the protrusion 12a and the recess 13b and the recess 12b and the protrusion 13a overlap each other (staggered arrangement). Thus, the protrusions 12a and 13a are formed. As shown in FIG. 2C, the permanent magnet 14 has a rectangular plate shape in which the moving direction of the mover 1 is the longitudinal direction. 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 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. The armature core 12, the armature core 13, and the permanent magnet 14 are arranged in a vertical posture inside the coil 11. The longitudinal directions of the armature core 12, the armature core 13, and the permanent magnet 14 are set to be the moving direction of the mover 1. The coil 11 is wound around the wide surfaces of the armature cores 12 and 13. The permanent magnet 14 is disposed between the armature core 12 and the armature core 13. As shown in FIG. 2C, the magnet 14 is magnetized in the direction from one side of the wide surface to the other, so that it is magnetized in the opposite direction of the armature cores 12 and 13. 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.

Since the armature cores 12 and 13 have 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.

  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, a lower plate portion 22, 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 flat soft magnetic metal plate and 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.

  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 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 excavating grooves on both sides of the portion to be the tooth portion while leaving the portion to be the tooth portion of the U-shaped soft magnetic steel sheet. In this case, the cost of the stator 2 can be reduced as compared with the case where the tooth portion is fixed by welding or the like by welding or screwing.

  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 can be efficiently flowed to the stator. If the length is shortened, the mover 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 portions 21a and the tooth portions 22a are alternately arranged (staggered arrangement) in the moving direction of the mover. The surfaces of the tooth portion 21a and the tooth portion 22a that face the movable element 1 do not face each other, but part of the surfaces may face each other. This is because thrust is generated even in such a case. However, when the entire surface is opposed, no thrust is generated in the mover 1.

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 the coil 11 of FIG. 6, a black circle in the circle indicates that a current flows from the back of the paper to the front. X in the circle indicates that current flows from the front to the back of the page. When energized in the direction indicated by the coil 11 in FIG. 6, when the mover 1 is outside the stator 2 (the energized mover is a single unit), the coil 11 causes the armature cores 12, 13 to have S on the upper side. The N pole is excited on the pole and 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 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. 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, the south pole is excited in the protrusion 13a of the armature core 13 on the right side of FIG. 7A (the back side in FIG. 6). The N pole is excited on the back side of the tooth portion 21a immediately above the magnetic pole. Normally, the N pole is excited in the lower projection 13a of the armature core 13, but there is no tooth portion 22a immediately below the lower projection 13a of the armature core 13, and the closest tooth portion is shown in FIG. 8A. Since it becomes the tooth part 22a, the state of excitation changes and it becomes the following flows. The lines of magnetic force pass through the magnet 14 sandwiched between the armature core 13 and the armature core 12 and flow into the armature core 12. As shown in FIG. 8A, the armature core 12 flows into the lower tooth portion 22a from the lower protrusion portion 12a. 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 flow from the lower protrusion 13a of the armature core 13 to the tooth 22a, but flow from the lower protrusion 12a of the armature core 12 to the lower tooth 22a. It will flow.

  7A and 8A, the lines of magnetic force lines shown in FIG. 6 are the fourth tooth portion 21a from the left side of the drawing in FIG. 6, the second uppermost protrusion portion 13a from the left side of the armature core 13, the magnet 14 (not shown in FIG. 6), the electric machine The child core 12 has a third lower projection 12a from the left and a fifth tooth 22a from the left. Here, the magnetic field lines passing through the second upper protrusion 13a and the magnet 14 from the left are not only the third lower protrusion 12a from the left of the armature core 12, but the left of the armature core 12, as shown in FIG. To the second lower projection 12a and the fourth tooth 22a from the left. The flow of magnetic field lines shown in FIG. 6 is also generated in the other portions.

Excitation of the armature cores 12 and 13 by energizing the coil 11 has been described with reference to FIGS. 6, 7A, and 8A. 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. 7B is a cross-sectional view taken along the line VII-VII in FIG. 6, similarly to FIG. 7A. 8B is a cross-sectional view taken along the line VIII-VIII in FIG. 6, similarly to FIG. 8A. FIG. 9 is an explanatory diagram showing the principle of thrust generation of a linear motor. As shown in FIGS. 7B and 8B, the magnet 14 is magnetized in the direction of the arrow. In this case, the arrow is magnetized so that the end point is N-pole and the start point is S-pole. Therefore, in FIG. 7B, the left armature core 12 is excited to the N pole, and the right armature core 13 is excited to the S pole. The same applies to FIG. 8B. In FIG. 9, the armature core 12 on the front side of the paper is excited to the N pole, and the armature core 13 on the back side of the paper is excited to the S pole. Considering the magnetic poles of the tooth portions 21a and 22a, as for the upper tooth portion 21a, the back side of the paper in FIG. 9 is excited to the N pole and the front side of the paper is not excited. As for the lower tooth portion 22a, the front side of the paper is excited to the S pole, and the back side of the paper is not excited (see FIGS. 7B and 8B). 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 right side of the drawing.
In FIG. 7, there is no tooth portion 22 a facing the protruding portion 13 a shown in the cross section, but the tooth portion 22 a facing the protruding portion 12 a located behind (in the direction of the back of the paper surface) the protruding portion 13 a should be visible. . Further, in FIG. 8, there is no tooth portion 21a facing the protruding portion 12a shown in the cross section, but the tooth portion 21a facing the protruding portion 13a located behind (in the rear surface direction of the paper) from the protruding portion 12a should be visible. . However, the description of the above description is omitted so as not to hinder understanding.

  FIG. 10 is an explanatory diagram showing the principle of thrust generation of the linear motor according to the first embodiment. FIG. 10 is a diagram showing a state where the mover 1 has moved to the right side from the state of FIG. 11 is a cross-sectional view taken along line XI-XI in FIG. 12 is a cross-sectional view taken along line XII-XII in FIG. FIG. 10 is a view when seen from the opening side of the stator 2. The left side of each of FIGS. 11 and 12 shows the front side of the page of FIG. In FIG. 10, 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 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. 10, how the mover 1 and the stator 2 are excited is integrated with the mover 1 and the stator 2 as in the case of FIG. 6. It is necessary to consider in the magnetic circuit.

  In FIG. 10, 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. 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. 11 and 12, the south pole is excited in the lower protrusion 13a of the armature core 13 on the right side of FIG. 11A (the back side in FIG. 10). An N pole is excited on the back side of the tooth portion 22a, which is directly below the magnetic pole. Normally, the N pole is excited in the upper protrusion 13a of the armature core 13, but there is no tooth portion 21a directly above the upper protrusion 13a of the armature core 13, and the closest tooth is the tooth shown in FIG. 12A. Since it becomes the part 21a, the state of excitation changes and it becomes the following flows. The lines of magnetic force pass through the magnet 14 sandwiched between the armature core 13 and the armature core 12 and flow into the armature core 12. As shown in FIG. 12A, the armature core 12 flows from the upper protrusion 12a to the upper tooth portion 21a. 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 lines of magnetic force do not flow from the upper protruding portion 13a of the armature core 13 to the tooth portion 21a, but flow through a path that flows from the upper protruding portion 12a of the armature core 12 to the upper tooth portion 21a. Become.

  11A and 12A, the lines of magnetic force lines shown in FIG. 10 are the fifth tooth portion 22a from the left in FIG. 10, the second lower protrusion 13a from the armature core 13, the magnet 14 (not shown in FIG. 10), the electric machine The protrusion 12a at the second upper part from the left of the child core 12 and the fourth tooth part 21a from the left. Here, the lines of magnetic force passing through the second lower protrusion 13a and the magnet 14 from the left are not only the second upper protrusion 12a from the left of the armature core 12, but the left of the armature core 12, as shown in FIG. To the third upper protrusion portion 12a and the fifth tooth portion 21a from the left. The flow of magnetic lines of force shown in FIG.

10, 11 </ b> A, and 12 </ b> A, the excitation of the armature cores 12 and 13 by energizing the coil 11 has been described. Next, the armature by the magnets 14 sandwiched between the armature cores 12 and 13. The principles of excitation of the cores 12 and 13 and the thrust generation principle of the linear motor will be described. 11B is a cross-sectional view taken along line XI-XI in FIG. 10 as in FIG. 11A. 12B is a cross-sectional view taken along the line XII-XII of FIG. 10 similarly to FIG. 12A. FIG. 13 is an explanatory diagram showing the principle of thrust generation of a linear motor. As shown in FIGS. 11B and 12B, the magnet 14 is magnetized in the direction of the arrow. In this case, the arrow is magnetized so that the end point is N-pole and the start point is S-pole. Therefore, in FIG. 11B, the left armature core 12 is excited to the N pole, and the right armature core 13 is excited to the S pole. The same applies to FIG. 12B. In FIG. 13, the armature core 12 on the front side of the paper is excited to the N pole, and the armature core 13 on the back side of the paper is excited to the S pole. Considering the magnetic poles of the tooth portions 21a and 22a, as for the upper tooth portion 21a, the front side of the paper in FIG. 13 is excited to the S pole and the back side of the paper is not excited. As for the lower tooth portion 22a, the back side of the paper is excited to the N pole, and the front side of the paper is not excited (see FIGS. 11B and 12B). 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 right side of the drawing. When the mover 1 moves to the right side, the same state as that shown in FIGS. 6 to 9 is obtained. By repeating the same operation in this manner, the mover 1 moves continuously.
In FIG. 11, there is no tooth portion 21 a that faces the protruding portion 13 a shown in the cross section, but the tooth portion 21 a that faces the protruding portion 12 a located behind (in the rear surface direction of the paper) the protruding portion 13 a should be visible. . In addition, in FIG. 12, there is no tooth portion 22a facing the protruding portion 12a shown in cross section, but the tooth portion 22a facing the protruding portion 13a located behind (in the direction of the back of the paper surface) from the protruding portion 12a should be visible. . However, the description of the above description is omitted so as not to hinder understanding.

  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 FIG. 7A, FIG. 8A, FIG. 11A, and FIG. 12A, the protrusion 12a of the armature core 12 on the front side (left side of the paper) is excited to the N pole at the upper and lower portions. The upper and lower protrusions 13a of the armature core 13 on the right side of the drawing are excited to the S pole or not excited.

  Next, the tooth portions 21a and 22a will be considered. As shown in FIGS. 7A and 12A, the back side of the tooth portion 21a is excited to the N pole or not excited. The front side is excited to the S pole or not excited. As shown in FIGS. 8A and 11A, the back side of the tooth portion 22a is excited to the N pole or not excited. The front side of the tooth portion 22a is excited to the S pole or not excited. In FIG. 7A and the like, the tooth portions 21a and 22a are not excited, or even if they are excited, a very weak state is indicated by zero. Further, in the tooth portions 21a and 22a, the left side (near side) and the right side (back side) are described, but the excitation states are not completely separated in the middle, and the tooth portions 21a and 22a. In the central part, it becomes the S pole or the N pole. There is a so-called overlap portion.

  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.

  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. 14 is a graph showing a normal hysteresis curve of iron. FIG. 15 is a graph showing hysteresis curves of the armature core and teeth 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 from comparison between FIG. 14 and FIG. 15, the area of the portion surrounded by the hysteresis curve in the present embodiment shown in FIG. 15 is larger 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 permanent magnets are used only for the mover 1, the amount of permanent magnets used does not increase even if the total movement distance is long. Further, the mover 1 has two rectangular plate-like armature cores 12 and 13 arranged in a vertical posture with a rectangular plate-like permanent magnet 14 interposed therebetween, and the armature cores 12 and 13 have tooth portions 21a and 22a. Protruding portions 12a and 13a are juxtaposed along the longitudinal direction on each of the opposing surfaces. 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 a staggered manner. As a result, the magnetic poles of the tooth portions 21a and 22a of the stator 2 change only from the residual value to the N or S pole, and from the N or S pole to the residual value, thereby reducing hysteresis loss and enabling high speed operation with low power. It becomes possible.

  Note that the magnetization direction of the magnet 14 is from the back side to the front side in FIG. 6 of the stator 2 as shown in FIG. 7B or 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. However, in the linear motor according to the first embodiment, the loop (magnetic flux loop) including the magnetic path passing through the stator 2 main body is in a direction perpendicular to the moving direction of the mover 1. Since it flows, the influence of the end effect can be reduced.

Embodiment 2
FIG. 16 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. 16, the groove 21a1 is formed along a direction perpendicular to the longitudinal direction of the tooth portion 21a, that is, along the short side 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. 16, 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. 17 is a perspective view showing the mover 1 of the linear motor according to the third embodiment. FIG. 18 is a plan view showing 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, the description thereof is omitted.

In Embodiment 3, since the whole structure of the needle | mover 1 is the same as that of Embodiment 1, the difference with Embodiment 1 is mainly demonstrated here.
In the third embodiment, the length of the protrusion 12a1 of the armature core 12 in the moving direction (the left-right direction in FIG. 18) is longer than the other protrusions 12a. Correspondingly, the protrusion 12a1 (not shown) on the opposite side of the protrusion 12a1 (the back side in FIG. 18) is also longer in the moving direction than the other protrusions 12a. The armature core 13 is the same as the armature core 12. The length in the moving direction of the recess 13b1 shown in FIG. 18 is longer than that of the other recess 13b. The length of the recess 13b1 (not shown) on the opposite side of the recess 13b1 in the moving direction is also longer than the other recesses 13b. In addition, although the position of the protrusion part 12a1 and the recessed part 13b1 from which length differs is made into the armature core 12 and the armature core 13 of the longitudinal direction, respectively, it is not restricted to it. The length in the moving direction of any one protrusion of the armature core 12 only needs to be longer than the other protrusions. The length in the moving direction of any one recess of the armature core 13 only needs to be longer than the other recesses. The positions in the movement direction of the protrusion 12a1 and the recess 13b1 do not need to match. Further, the length of the concave portion of the armature core 12 and the length of the protruding portion of the armature core 13 in the moving direction may be changed. Furthermore, the length of the specific protrusion in the moving direction is made longer than the other protrusions, and the length of the specific recess in the moving direction is longer than that of the other concave parts. But it ’s okay.

  In the first embodiment, the armature core 12 has a substantially rectangular shape in plan view. On the other hand, in the third embodiment, the armature core 12 has a substantially parallelogram shape in plan view not including a rectangle as shown in FIG. The projecting portions 12a and 12a1 of the armature core 12 and the recess 12b of the armature core 12 have end faces (surfaces facing the plate-like portions 21 and 22) that are substantially parallelograms that do not include a rectangle. Of the surfaces constituting the protrusions 12a and 12a1, the surface with respect to the moving direction is inclined.

  Like the armature core 12, the armature core 13 has a substantially parallelogram shape that does not include a rectangle in plan view (see FIG. 18). The projecting portions 13a of the armature core 13 and the end surfaces of the recesses 13b and 13b1 of the armature core 13 (surfaces facing the plate-like portions 21 and 22) are substantially parallelograms. Of the surfaces constituting the protrusion 13a, the surface with respect to the moving direction is inclined.

As with the armature cores 12 and 13, the permanent magnet 14 has a substantially parallelogram shape that does not include a rectangle in plan view (see FIG. 18). The lengths in the moving direction (longitudinal direction) of the armature cores 12 and 13 and the permanent magnet 14 are substantially the same. Similar to the first embodiment, the mover 1 has a configuration in which a permanent magnet 14 is disposed between an armature core 12 and an armature core 13, and a coil 11 is wound around them.
Unlike the first embodiment, the protrusions 12a and 13a have a configuration in which the surface with respect to the moving direction is inclined as shown in FIG. The protrusions 12a and 13a are so-called skewed. Such a configuration is a configuration for reducing the detent force.

  Since the relative permeability of the mover 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 recess 13b1 of the armature core 13 is set to the other armature core 12. The protrusion 12a and the other recess 13b of the armature core 13 are 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 at the protrusion 12a1 and the protrusion 12a differs by 180 degrees in the sixth harmonic component, so the sixth harmonic component is canceled and reduced. In addition, although the protrusion part 12a1 of the armature core 12 was lengthened only by τ / 6, even if the protrusion part 12a1 of the armature core 12 is shorter than the protrusion parts 12a of other armature cores 12 by τ / 6, There is an effect. That is, an armature core having a length different from that of the other protrusions 12a by τ / 6 may be provided.

  Next, the 12th and higher harmonic components can be reduced by arranging the protrusions 12a and 12a1 of the armature core 12 and the protrusion 13a of the armature core 13 in a skewed manner. The skew arrangement is to form the protrusions 12a and 12a1 of the armature core 12 and the protrusion 13a 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 recesses 13b and the recesses 13b1 of the armature core 13 are changed, and the skews of the protrusions 12a, 12a1, and 13a are performed. In such a configuration, the length of the armature core protrusion 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 the recesses 13b1.

  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. 19 is a cross-sectional view showing a configuration of the stator 2 of the linear motor according to the fourth embodiment. FIG. 3 is a cross-sectional view of the linear motor stator 2 cut along the moving direction of the mover 1. 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. 19, 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. 19, 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. 19, 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.

Regarding the mover 1, since the above-described first embodiment is the same as the second embodiment or the third embodiment, the description thereof is 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 12a (12a1) of the armature core 12 of the mover 1 and the protrusion 13a of the armature core 13 are arranged. The detent force can be reduced without skewing.
Note that the same movable element as that of the above-described third embodiment can be used. In order to reduce the detent force, the tooth portions 21a and 22a of the stator 2 and the protrusion 12a (12a1) of the armature core 12 of the mover 1 and the moving direction of the mover 1 of the protrusion 13a of the armature core 13 are set. Angle is involved. Each of the teeth 21a and 22a of the stator 2, the protrusion 12a (12a1) of the armature core 12 of the mover 1, and the protrusion 13a of the armature core 13 is skewed so that the angle formed becomes an appropriate value. You can do it.

Embodiment 5
FIG. 20 is a cross-sectional view showing the configuration of the stator 2 of the linear motor according to the fifth embodiment. FIG. 3 is a cross-sectional view of the linear motor cut along the moving direction of the mover 1. 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 is the same as that in the first embodiment, the second embodiment, or the third embodiment described above, and thus the description thereof is 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. 20, the short cross-sections E1 and E2 of the tooth portion 21a and the short cross-sections E3 and E4 similar to the short end face 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 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, 13 Armature core 12a, 13a Protrusion part (protrusion part)
12b, 13b Recessed portion 14 Permanent magnet (magnet)
2 Stator 21 Upper plate part (plate-like part)
21a tooth part 22 lower plate part (plate-like part)
22a tooth part 23 side plate part 12a1 protrusion part (protrusion part)
13b1 recess

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, the two plate-like portions are opposed to each other with the moving region of the mover in between, and are magnetically coupled,
To each of the two opposing surfaces of the two plate-like portions, a rectangular parallelepiped tooth portion, so that at least a portion of the tooth portion of one plate-like portion and the tooth portion of the other plate-like portion do not face each other, Juxtaposed in the direction of movement,
The mover has a rectangular plate-shaped magnet and two armature cores arranged vertically in the coil, both having the moving direction as a longitudinal direction.
Each of the surfaces of the armature core that faces the plate-like portion has protrusions along the longitudinal direction,
The magnet is disposed between the two armature cores, and the protruding portion of one armature core and the protruding portion of the other armature core are arranged in a staggered manner,
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 projecting portion that faces the plate-like portion is a substantially parallelogram. The linear motor according to any one of claims 1 to 3, wherein the protrusion includes a protrusion having a length different from that of the other protrusion in the moving direction. 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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