JP2018148760A - Linear motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a linear motor in which the influence of a magnetic attraction force acting between a stator and a mover is sufficiently reduced. SOLUTION: A linear motor in which a coil wound around a core 20 is arranged on a mover 12, and a first permanent magnet 18 for driving a mover facing the stator 10 is arranged on the stator 10. In the stator, the second permanent magnet 24, which is a permanent magnet different from the first permanent magnet, is arranged, and on the mover, the third permanent magnet 26, which is another permanent magnet, is used as the second permanent magnet. They are arranged so as to face each other and generate a magnetic repulsive force with the second permanent magnet. The magnetic repulsive force cancels at least a part of the magnetic attractive force generated between the first permanent magnet and the core. [Selection diagram] Fig. 1

Description

  The present invention relates to a linear motor including a permanent magnet in one of a stator and a mover and a coil in the other.

  In the linear motor in which one of the coil wound around the core and the permanent magnet is arranged in the stator and the other is arranged in the mover, the influence of the magnetic attractive force between the stator and the mover is a problem. For example, in the linear motor described in the following patent document, an attempt is made to eliminate the influence of the magnetic attraction force by applying a magnetic attraction force in opposite directions to the mover.

JP2015-130754A

However, in the linear motor described in the above-mentioned patent document, although the magnetic attraction force in the opposite direction is offset to some extent with respect to the mover, each of the two portions of the stator facing each other with the mover interposed therebetween The magnetic attraction force still acts, and the linear motor described in the above patent document is not necessarily sufficient in terms of eliminating the influence of the magnetic attraction force.
The present invention has been made from such a viewpoint, and an object of the present invention is to provide a linear motor in which the influence of the magnetic attractive force acting between the stator and the mover is sufficiently reduced.

In order to solve the above problems, the linear motor of the present invention is
A stator that extends in one direction and in which one of a coil wound around a core and a permanent magnet is arranged;
A linear motor comprising: a mover that moves in the one direction along the stator and has the other of the coil and the permanent magnet disposed so as to face the one of the coil and the permanent magnet. Because
When the permanent magnet is a first permanent magnet, a second permanent magnet, which is a permanent magnet different from the first permanent magnet, is arranged in the one direction on the stator, and the movable element has the first permanent magnet. A third permanent magnet, which is a permanent magnet different from the one permanent magnet, is disposed so as to face the second permanent magnet and generate a magnetic repulsive force with the second permanent magnet.

  According to the linear motor of the present invention, the magnetic attraction force generated between the first permanent magnet and the core and the second permanent magnet and the third permanent magnet are generated between the stator and the mover. Since the magnetic repulsive force (repulsive force) acts, it is possible to reduce the influence of the magnetic attractive force. That is, the rigidity of the linear motor itself and the apparatus in which the linear motor is employed can be reduced.

It is a perspective view which shows the linear motor of an Example. It is sectional drawing which shows the cross section of the linear motor of an Example typically. It is a conceptual diagram for demonstrating the effect | action of the linear motor of an Example.

  Hereinafter, as a mode for carrying out the present invention, a linear motor as an example will be described in detail with reference to the drawings. In addition, the linear motor of this invention can be implemented with the various form which gave various change and improvement based on the knowledge of those skilled in the art besides the following Example.

[A] Configuration of Linear Motor of Example As shown in FIG. 1, the linear motor of the example includes a stator 10 extending in one direction, and a mover 12 movable in one direction along the stator 10. It is comprised including. Incidentally, in the figure, one direction, that is, the moving direction of the mover 12 is indicated by a white arrow.

  The stator 10 has a groove shape (channel shape) having a pair of facing portions 14 facing each other with a gap therebetween and a connecting portion 16 that connects the facing portions 14 at a lower portion. In other words, the cross-sectional shape is a U-shape that opens upward. The mover 12 is configured to move between a pair of opposed portions 14. That is, this linear motor is a so-called T-type linear motor.

Referring to FIG. 2 (a) schematically showing the cross section of IIA in FIG. 1 and FIG. 2 (b) schematically showing the cross section of IIB, A plurality of first permanent magnets 18, each of which is a permanent magnet for driving the mover 12, are arranged in one direction. The mover 12 is provided with three cores 20 each made of a laminate of electromagnetic steel plates and three coils 22 wound around the cores 20 so as to face the first permanent magnets 18. ing.

  As shown in FIG. 2A, the first permanent magnets 18 are arranged so that the polarities are alternately opposite in the arrangement direction, in other words, the N poles and the S poles are alternately arranged. By supplying a three-phase alternating current to the three coils 22, the mover 12 moves in one direction. That is, this linear motor is a three-phase linear motor.

  On the other hand, each of the pair of opposed portions 14 of the stator 10 has two second permanent magnets 24 that are different from the first permanent magnet 18 so as to sandwich the first permanent magnet 18 vertically. Arranged in columns. The movable element 12 is provided with a pair of third permanent magnets 26 so as to face the second permanent magnets 24 so as to sandwich the coil 22 vertically.

  As shown in FIG. 2 (b), the second permanent magnets 24 arranged in the left facing portion 14 are arranged so that the N poles face inward, and conversely, The second permanent magnets 24 arranged in the facing portion 14 are all arranged so that the south pole faces inward. On the other hand, the third permanent magnet 26 facing the second permanent magnet 24 of the opposing portion 14 on the left side, that is, the third permanent magnet 26 disposed on the left side of the mover 12 has the north pole facing outward. The third permanent magnet 26 arranged on the right side of the movable element 12, that is, the third permanent magnet 26 arranged on the right side of the mover 12, faces the S pole outward. Arranged. That is, in the present linear motor, the second permanent magnet 24 and the third permanent magnet 26 are arranged such that the same poles face each other.

  Note that the arrangement pitch of the second permanent magnets 24 in one direction and the arrangement pitch of the first permanent magnets 18 are the same (the pitch indicated by P in the drawing), and the second arrangement in one direction is the second. Each is arranged so that the permanent magnet 24 and the first permanent magnet 18 are located at the same position.

[B] Operation of Linear Motor of Embodiment As a premise for explaining the operation of the linear motor of the embodiment, the operation of a general linear motor will be described. As shown in FIG. 3A, the linear motor of the embodiment is also the same, but in the general linear motor, the core 20 of the mover 12 and the first permanent magnets 18 arranged on the stator 10 are included. A magnetic attractive force (indicated by a white arrow in the figure) acts between the core 20 and the core 20 facing the core. This magnetic attraction force is a force generated even when the coil 22 is not energized.

  In general, in an apparatus in which the linear motor is mounted, the stator is fixedly supported on the base body 30, and the mover 12 is fixedly supported on a moving body 32 that is moved by the linear motor. The moving body 32 is guided by a guide provided on the base body 30 and can move in one direction. Specifically, in FIG. 3A, a pair of rails 34 as guides are laid on the base body 30, and a pair of slides 36 that engage with each of the pair of rails 34 are attached to the moving body 32. Is provided. That is, the moving body 32 is movable with respect to the base body 30 through a guide mechanism including the rail 34 and the slide 36.

  The guide mechanism is relatively strong. For example, when the stator 10 is fixedly supported on the base body 30 at the connecting portion 16 as shown in the drawing, the magnetic attraction force described above is used. Accordingly, it is expected that each of the pair of facing portions 14 is inclined inward as indicated by a two-dot chain line in the drawing. In order to prevent the inclination, for example, as shown by a two-dot chain line in the left part of the figure, a stay 40 is provided for the facing part 14 or in the right part of the figure by a two-dot chain line. As shown, it is necessary to consider increasing the thickness of the facing portion 14 itself. Further, in the assembly of the apparatus, the workability of the assembly becomes poor due to the action of the magnetic attractive force.

  Considering the influence of the magnetic attraction force, the linear motor of the embodiment is provided with the second permanent magnet 24 and the third permanent magnet 26 described above. In the linear motor of the embodiment, a magnetic repulsive force (so-called repulsive force) is generated between the second permanent magnet 24 and the third permanent magnet 26, as indicated by black arrows in FIG. The magnetic repulsive force acts to cancel at least a part of the above-described magnetic attractive force.

  By the action of the magnetic repulsive force, in the linear motor of the embodiment, the rigidity of the stator 10 itself and the structure for the base 30 to fix and support the stator 10 can be made relatively low. It becomes. As a result, it is possible to reduce the size of the linear motor and the size of the device on which the linear motor is mounted, and to facilitate the work of assembling the device.

  In the linear motor of the embodiment, since the arrangement pitch of the second permanent magnets 24 and the arrangement pitch of the first permanent magnets 18 are equal, the magnetic attraction force and the magnetic force according to the position of the mover 12 are set. The fluctuation of the balance with the repulsive force is kept small.

[C] Modified Example In the linear motor of the above embodiment, the first permanent magnet 18 that is a permanent magnet for driving the mover 12 is arranged on the stator 10, and the core 20 and the coil 22 are arranged on the mover 12. However, the present invention is also applicable to a linear motor in which a core and a coil are arranged in a stator, and permanent magnets for driving are arranged in a mover so as to face the core and the coil.

  The linear motor of the above embodiment is a so-called T-type linear motor in which the stator 10 has a pair of opposed portions 14 and the movable element 12 moves between the opposed portions 14. However, the present invention is not such a linear motor. For example, a permanent magnet for driving a mover, or a core and a coil are arranged in a single row on the stator, so that one side of the mover faces them. In addition, the present invention can also be applied to a motor in which a core and a coil or a permanent magnet for driving a mover are arranged, that is, a so-called F-type linear motor.

  In the linear motor of the above-described embodiment, the second permanent magnets 24 are arranged in two rows so as to sandwich the first permanent magnet 18 in one facing portion 14 of the stator 10. The two third permanent magnets 26 are arranged on the upper and lower sides so as to face the permanent magnet 24. However, the linear motor of the present invention excludes the second permanent magnets 24 in any row, and the removed rows. The two third permanent magnets 26 facing the second permanent magnet 24 may be eliminated. Specifically, in the linear motor of the embodiment, since the connecting portion 16 is disposed on the lower end side of the pair of facing portions 14, the second permanent magnets 24 in the lower row are eliminated, and the lower side Even if the third permanent magnet 26 is eliminated, it is possible to sufficiently suppress the pair of facing portions 14 from inclining to the inside.

  In the linear motor of the above embodiment, the plurality of second permanent magnets 24 are arranged in one direction, but one long second permanent magnet may be arranged. Such an aspect can also be considered as an aspect in which the second permanent magnets are arranged in one direction. In the linear motor of the above embodiment, the third permanent magnets 26 that are relatively long in one direction are disposed. However, a plurality of third permanent magnets that are relatively short are arranged in a line in one direction. Also good.

  DESCRIPTION OF SYMBOLS 10: Stator 12: Movable element 14: Opposing part 16: Connection part 18: 1st permanent magnet 20: Core 22: Coil 24: 2nd permanent magnet 26: 3rd permanent magnet 30: Base | substrate 32: Moving body 34: Rail 36: Slide 40: Stay

Claims (7)

A stator that extends in one direction and in which one of a coil wound around a core and a permanent magnet is arranged;
A linear motor comprising: a mover that moves in the one direction along the stator and has the other of the coil and the permanent magnet disposed so as to face the one of the coil and the permanent magnet. Because
When the permanent magnet is a first permanent magnet, a second permanent magnet, which is a permanent magnet different from the first permanent magnet, is arranged in the one direction on the stator, and the movable element has the first permanent magnet. A third permanent magnet, which is a permanent magnet different from the one permanent magnet, faces the second permanent magnet and is arranged so as to generate a magnetic repulsive force with the second permanent magnet. motor.   The linear motor according to claim 1, wherein the first permanent magnet is arranged on the stator and the coil is disposed on the mover. The stator includes a pair of opposed portions opposed to each other with a space therebetween, and the movable element is configured to move between the pair of opposed portions.
The second permanent magnets are arranged in each of the pair of opposed portions, and a pair of third permanent magnets each functioning as the third permanent magnet are arranged in each of the pair of opposed portions. The linear motor according to claim 1, wherein the linear motor is disposed on the movable element so as to face the second permanent magnet. The second permanent magnets are arranged in two rows with the stator sandwiching the one of the coil and the first permanent magnet,
The third permanent magnet is disposed on the mover so as to sandwich the other of the coil and the first permanent magnet so as to face each row of the second permanent magnet. Item 4. The linear motor according to any one of Items 3.   The pitch of the arrangement of the second permanent magnets and the pitch of the one arrangement of the coils and the first permanent magnets arranged in the stator are made equal in the moving direction of the mover. The linear motor according to any one of claims 1 to 4.   2. The stator according to claim 1, wherein the stator is fixedly supported by a base, and the movable element is guided and supported by a movable body guided in a guide provided on the base and movable in the one direction. The linear motor according to claim 5.   7. The apparatus according to claim 1, wherein at least part of a magnetic attractive force generated between the first permanent magnet and the core is canceled by the magnetic repulsive force. 8. Linear motor.

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