JP5300325B2 - Linear motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a linear motor which improves acceleration performance by reducing weight of a magnet fixing member of a mover. <P>SOLUTION: The linear motor includes a stator comprising an armature generating a moving magnetic field by energization, and the mover which is oppositely arranged apart by a prescribed distance from the stator and moves on the stator by the moving magnetic field. The mover includes a plate-shaped multipolar field magnetic pole which arranges at least 3 pieces of an odd number of rectangular parallelepiped main pole permanent magnets magnetized in a vertical direction to the stator and a rectangular parallelepiped sub-pole permanent magnets to run magnetic flux by being magnetized in a moving direction of the mover alternately along the moving direction by Halbach array and a non-magnetic holder which holds sides and moving direction ends of the plate-shaped multipolar field magnetic pole. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a moving magnet type linear motor that is provided in an industrial machine such as a machine tool or a semiconductor manufacturing apparatus and is used for axial feed and conveyance.

  Conventionally, a Halbach magnet array having a plurality of main magnetic pole permanent magnets magnetized in the direction of the generated magnetic field, a sub magnetic pole permanent magnet disposed between the main magnetic pole permanent magnets, and a back yoke for fixing the permanent magnet is provided. In the periodic magnetic field generator, the back yoke is provided with a concavo-convex portion, a main magnetic pole permanent magnet is disposed in the concave portion, a sub magnetic pole permanent magnet is disposed in the convex portion, and at least two sub magnetic pole permanent magnets are disposed, There is a periodic magnetic field generator in which the height of the sub magnetic pole permanent magnet in the magnetic field generation direction is lower than the height of the main magnetic pole permanent magnet (see, for example, Patent Document 1).

  Further, conventionally, several pole main pole magnets magnetized so as to alternately form NS magnetic poles in the radial direction, and several pole magnets that allow magnetic flux to flow from both sides in the circumferential direction of the main pole magnet, There is a rotor of a rotating electrical machine including a heat conductive metal heat radiating member in which the main magnetic pole magnet and the yoke magnet are fixed in close contact (for example, see Patent Document 2).

JP 2007-110822 A JP 2004-350427 A

  However, according to the conventional technique described in Patent Document 1, an uneven portion is provided on the back yoke, a main magnetic pole permanent magnet is disposed in the concave portion, and a sub magnetic pole permanent magnet is disposed and bonded to the convex portion. Therefore, there is a problem that the back yoke as the magnet fixing member increases the weight of the mover and the acceleration performance of the mover is lowered.

  Further, according to the conventional technique described in Patent Document 2, the permanent magnet is enclosed and fixed in a resin hub. For this reason, there is a problem that the hub as the magnet fixing member increases the weight of the rotor and the acceleration performance of the rotor decreases.

  The present invention has been made in view of the above, and an object of the present invention is to obtain a linear motor in which acceleration performance is improved by reducing the weight of a magnet fixing member of a mover.

In order to solve the above-described problems and achieve the object, the present invention includes a stator composed of an armature that generates a moving magnetic field when energized, and a fixed distance from the stator that is disposed opposite to the stator. In the linear motor comprising a mover that moves on the stator, the mover is magnetized in a moving direction of the mover and a rectangular parallelepiped main magnetic pole permanent magnet that is magnetized in a direction perpendicular to the stator. A rectangular parallelepiped permanent magnet permanent magnet that circulates the magnetic flux, and a Halbach array that alternately arranges along the moving direction, and at least three or more odd-numbered flat plate-like multipolar field magnetic poles, A non-magnetic holder that holds the side surface of the flat plate-shaped multipolar field magnetic pole and the end surface in the moving direction, and the flat plate-shaped multipole field magnetic pole has a plurality of penetrating holes extending between the end surfaces in the moving direction. A hole is formed and the non-magnetic The rudder is formed with respective holes opposed to the plurality of through holes, and the end of the fastening rod 43 that protrudes from the end surface in the moving direction through the through hole of the multi-pole field magnetic pole The magnetic holder is fitted into a hole .

  According to the present invention, a magnet fixing member such as a back yoke or a hub is unnecessary, and the moving element of the moving magnet type linear motor can be reduced in weight. In addition, since a member such as a hub existing between the mover and the stator is eliminated, the gap between the mover and the stator can be reduced, and the magnetic flux of the permanent magnet of the mover is transferred to the stator coil. It can work effectively. Therefore, it is possible to increase the thrust of the linear motor and improve the acceleration performance.

  Embodiments of a linear motor according to the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

Embodiment 1 FIG.
1 is a perspective view of a moving magnet type linear motor showing a first embodiment of the linear motor according to the present invention, and FIG. 2 is an exploded perspective view showing a mover of the linear motor of the first embodiment. FIG. 3 is a perspective view showing a modification of the mover of the linear motor according to the first embodiment. FIG. 4 is a plan view showing another modification of the mover of the linear motor according to the first embodiment. .

  As shown in FIG. 1, the linear motor 10 includes a stator 30 formed of an armature that generates a moving magnetic field when energized, and a stator 30 that is disposed to face the stator 30 with a predetermined interval therebetween. And a mover 20 that moves on 30.

  A coil (not shown) is mounted on the magnetic teeth (not shown) of the stator 30, and the stator 30 generates a moving magnetic field that moves the mover 20 along the arrangement direction of the magnetic teeth by passing an alternating current through the coil. It has become an armature. The mover 20 is supported by a linear guide (not shown) installed in parallel to the stator 30 and moves on the stator 30.

  As shown in FIG. 2, the mover 20 according to the first embodiment includes seven (at least three or more odd numbers) rectangular parallelepiped permanent magnets 41 and 42 in the moving direction of the mover 20 (the magnetic poles of the stator 30). A multi-pole field magnetic pole 40 having a rectangular flat plate shape as a whole is arranged along the teeth arrangement direction. The arrangement of the permanent magnets of the multipole field magnetic pole 40 includes a main magnetic pole permanent magnet 41 magnetized in a direction perpendicular to the stator 30 and a supplementary magnetic pole permanent magnet 42 magnetized in the moving direction of the mover 20 to circulate the magnetic flux. And a so-called Halbach array in which these are alternately arranged.

  The permanent magnets 41 and 42 are formed with a plurality (two) of through holes 40a in the moving direction. That is, a plurality of through holes 40a penetrating between the movement direction end faces 40c, 40c are formed in the flat plate-like multipole field magnetic pole 40. A round bar-like fastening rod 43 is inserted into each of the through holes 40a, and the permanent magnets 41 and 42 are fixed in a Halbach array. The fastening rod 43 protrudes from both end faces 40c of the multipole field magnetic pole 40 arranged in Halbach.

  The non-magnetic holder 21 on the rectangular flat plate fits and holds the side surface 40b and the moving direction end surface 40c of the rectangular flat plate-like multipole field magnetic pole 40 in a rectangular hole 21a formed in the center. ing. The non-magnetic holder 21 is formed with a hole 22 that faces each of the plurality of through holes 40a of the multipole field magnetic pole 40, and protrudes from the moving direction end face 40c through the through hole 40a of the multipole field magnetic pole 40. The end of the fastening rod 43 is fitted in the hole 22 of the nonmagnetic holder 21.

  The non-magnetic holder 21 has a substantially U-shaped first holder 21b in which a hole 22 into which one end of the fastening rod 43 is fitted and a hole 22 in which the other end of the fastening rod 43 is fitted. The first and second holders 21b and 21c are fastened together with the multipole field magnetic pole 40 by fastening bolts 23 as fastening members.

  By forming the multipole field magnetic pole 40 and the nonmagnetic holder 21 as described above, a back yoke or a hub having irregularities for fixing the permanent magnets 41 and 42 becomes unnecessary. In particular, since the surface facing the stator 30 and the back surface of the surface of the multipole field magnetic pole 40 are not covered, the mover 20 is reduced in weight. Further, since the two fastening rods 43 are passed through the multipole field magnetic pole 40, there is an additional effect that rotational vibration of the multipole field magnetic pole 40 having an axis parallel to the fastening rod 43 as a rotation axis is suppressed. .

  In the multipole field magnetic pole 40 shown in FIG. 2, the permanent magnets at both ends are the main magnetic pole permanent magnets 41, but the permanent magnets at both ends may be the complementary magnetic pole permanent magnets 42 as shown in FIG. 3. If the permanent magnets at both ends are the complementary magnetic pole permanent magnets 42, the influence of the magnetic field on the periphery of the mover 20 can be reduced. The material of the fastening rod 43 is preferably a nonmagnetic material such as stainless steel. If a nonmagnetic material is used, the leakage magnetic flux can be reduced and the thrust of the mover 20 can be increased.

  As shown in FIG. 1, in the linear motor 10 of the first embodiment, the length of the stator 30 is longer than the length of the mover 20, but the present invention is not limited to this. The length of the stator 30 may be shorter than the length of the mover 20. Even when the length of the stator 30 is shorter than the length of the mover 20, the mover 20 can be reduced in weight by applying the present invention.

  Further, as shown in FIG. 2, the end portions of the fastening rod 43 protruding from both end faces 40c of the multipole field magnetic pole 40 are fitted in the holes 22 provided in the nonmagnetic holder 21, but in FIG. As shown, the length of the fastening rod 43 is made shorter than the length of the multipole field magnetic pole 40, the hole 45 is left at the end of the multipole field magnetic pole 40, and the pin 25 is installed on the nonmagnetic holder 21 side. The pin 25 may be fitted into the hole 45.

Embodiment 2. FIG.
FIG. 5 is an exploded perspective view showing the mover of the linear motor according to the second embodiment of the present invention. In the mover 20a of the second embodiment, the permanent magnets 41 and 42 are formed with one through-hole 40f having a rectangular cross section in the moving direction. That is, the flat plate-shaped multipole field magnetic pole 40 is formed with one through-hole 40f having a rectangular cross section penetrating between the movement direction end faces 40c, 40c.

  A fastening rod 43a having the same rectangular cross section is inserted into the one through hole 40f, and the permanent magnets 41 and 42 are fixed in a Halbach array. The fastening rod 43a protrudes from both end faces 40c of the multipole field magnetic pole 40 arranged in the Halbach array.

  The non-magnetic holder 21 on the rectangular flat plate fits and holds the side surface 40b and the moving direction end surface 40c of the rectangular flat plate-like multipolar field magnetic pole 40 in a rectangular hole 21a formed in the center. . The nonmagnetic holder 21 is formed with a rectangular hole 22a facing one rectangular through hole 40f of the multipole field magnetic pole 40, and penetrates the through hole 40f of the multipole field magnetic pole 40 to move in the moving direction end face 40c. The end of the fastening bar 43 a having a rectangular cross section protruding from the rectangular hole 22 a of the nonmagnetic holder 21 is fitted into the end.

  The mover 20a according to the second embodiment is a portion other than the one rectangular through hole 40f of the multipolar field magnetic pole 40 described above, one fastening rod 43a having a rectangular cross section, and the rectangular hole 22a of the nonmagnetic holder 21. Is equivalent to the mover 20 of the first embodiment.

  The mover 20a of the second embodiment has an advantage that the number of parts is smaller than that of the mover 20 of the first embodiment. Although one fastening rod 43a is provided, since the cross-sectional shape of the fastening rod 43a is rectangular, the effect of suppressing rotational vibration around the fastening rod 43a is equivalent to that of the mover 20 of the first embodiment.

  In the mover 20a of the second embodiment shown in FIG. 5, the cross-sectional shapes of the fastening rod 43a and the hole 22a are rectangular. However, the cross-sectional shapes of the fastening rod and the hole may be polygonal, gear-shaped, or elliptical. Even if it is such a shape, the same effect as the case of a rectangular cross section can be acquired. In practice, it is better to have a 4 to hexagonal shape. In the octagonal or decagonal shape, the corner becomes an obtuse angle larger than 120 °, and the life until the corner is worn due to rotational vibration and impairs the rotation prevention function is shortened.

  If the hexagonal shape is used, the life until the anti-rotation function is impaired is long like a hexagonal bolt. Moreover, if it is a polygon below a hexagon, the lifetime until it impairs a rotation prevention function is long. Triangular, gear-shaped, or elliptical shapes are difficult to process and increase the processing cost. As described above, the cross-sectional shapes of the fastening rod and the hole are preferably four to hexagonal.

Embodiment 3 FIG.
FIG. 6 is a plan view showing the mover of the linear motor according to the third embodiment of the present invention. In the mover 20 b of the third embodiment, a spacer 46 is disposed between the permanent magnets 41 and 42. The mover 20b of the third embodiment is the same as the mover 20 of the first embodiment except that the spacer 46 is disposed.

  By arranging the spacer 46 between the permanent magnets 41 and 42, demagnetization of the permanent magnets 41 and 42 can be prevented. Further, since the main magnetic pole permanent magnet 41 and the auxiliary magnetic pole permanent magnet 42 having different magnetization directions are arranged apart from each other by the spacer 46, a sudden change in the flow of magnetic flux can be prevented. When the flow of magnetic flux changes abruptly, the magnetic flux density component in the same direction as the magnetization direction of the permanent magnet may decrease and demagnetization may occur, but the mover 20b of the third embodiment has an effect of preventing this. .

  Further, the length L1 of the multipole field magnetic pole 40 is set slightly longer than the length L2 of the hole 21a of the nonmagnetic holder 8 by the spacer 46 arranged on the moving direction end face 40c of the multipole field magnetic pole 40. By setting L1> L2, the tightening force of the multipole field magnetic pole 40 by the nonmagnetic holder 21 can be increased, and the rigidity of the mover 20b can be increased.

  Further, the thickness of each permanent magnet 41, 42 is measured in advance, and the thickness of each spacer 46 is selected or arranged so that the arrangement pitch of the permanent magnets 41, 42 (hereinafter referred to as pole pitch) is constant over the entire length. It is desirable to arrange after processing. In this way, even if the thicknesses of the permanent magnets 41 and 42 have manufacturing errors, the pole pitch can be set to a predetermined value, and thrust pulsation and cogging thrust can be reduced.

Embodiment 4 FIG.
FIG. 7 is an exploded perspective view showing the nonmagnetic holder according to the fourth embodiment of the linear motor according to the present invention. In the nonmagnetic holder 20c of the fourth embodiment, a set pin 27 is provided on the joining surface 21f of the first holder 21b, and a pin hole 28 is provided on the joining surface of the second holder 21c. The second holder 21c is integrally fastened together with the multipole field magnetic pole 40 by the fastening bolt 23 in a state where the set pin 27 is fitted in the pin hole 28.

  By the fitting of the set pin 27 and the pin hole 28, the relative positioning of the first holder 21b and the second holder 21c is accurately performed, and the precise flatness of the mover 20 can be ensured.

  As described above, the linear motor according to the present invention is useful for axial feed and conveyance of industrial machines such as machine tools and semiconductor manufacturing apparatuses.

It is a perspective view which shows Embodiment 1 of the linear motor concerning this invention. FIG. 3 is an exploded perspective view illustrating a mover of the linear motor according to the first embodiment. FIG. 6 is an exploded perspective view showing a modification of the mover of the linear motor according to the first embodiment. FIG. 10 is a plan view illustrating another modification of the mover of the linear motor according to the first embodiment. It is a disassembled perspective view which shows the needle | mover of Embodiment 2 of the linear motor concerning this invention. It is a top view which shows the needle | mover of Embodiment 3 of the linear motor concerning this invention. It is a disassembled perspective view which shows the nonmagnetic holder of Embodiment 4 of the linear motor concerning this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Linear motor 20, 20a, 20b, 20c Movable element 21 Nonmagnetic holder 21a Hole 21b 1st holder 21c 2nd holder 21f Joining surface 22, 22a Hole 23 Fastening bolt 25 Pin 27 Set pin 28 Pin hole 30 Stator 40 Multipole field magnetic pole 40a, 40f Through hole 40b Side surface 40c End face in moving direction 41 Main magnetic pole permanent magnet 42 Complementary magnetic pole permanent magnet 43, 43a Fastening rod 45 Hole 46 Spacer

Claims (6)

A stator composed of an armature that generates a moving magnetic field when energized;
A mover that is disposed opposite to the stator at a predetermined interval and moves on the stator by the moving magnetic field;
In a linear motor comprising
The mover is
A rectangular parallelepiped main magnetic pole permanent magnet magnetized in a direction perpendicular to the stator and a rectangular parallelepiped auxiliary magnetic pole permanent magnet which is magnetized in the moving direction of the mover and circulates a magnetic flux are alternately arranged along the moving direction. By the Halbach array arranged in a flat plate-like multipole field magnetic pole arranged at least an odd number of 3 or more,
A non-magnetic holder for holding the side surface and the moving direction end surface of the flat plate-like multipole field magnetic pole,
Equipped with a,
The flat plate-like multipole field magnetic pole is formed with a plurality of through holes penetrating between the end faces in the moving direction,
The non-magnetic holder is formed with respective holes facing the plurality of through holes,
A linear motor characterized in that an end portion of a fastening rod that penetrates the through hole of the multipole field magnetic pole and protrudes from an end surface in the moving direction is fitted in a hole of the nonmagnetic holder . A stator composed of an armature that generates a moving magnetic field when energized;
A mover that is disposed opposite to the stator at a predetermined interval and moves on the stator by the moving magnetic field;
In a linear motor comprising
The mover is
A rectangular parallelepiped main magnetic pole permanent magnet magnetized in a direction perpendicular to the stator and a rectangular parallelepiped auxiliary magnetic pole permanent magnet which is magnetized in the moving direction of the mover and circulates a magnetic flux are alternately arranged along the moving direction. By the Halbach array arranged in a flat plate-like multipole field magnetic pole arranged at least an odd number of 3 or more,
A non-magnetic holder for holding the side surface and the moving direction end surface of the flat plate-like multipole field magnetic pole,
With
The flat plate-like multipole field magnetic pole is formed with one through-hole having a polygonal or gear-shaped cross section passing between the end faces in the moving direction,
In the non-magnetic holder, a cross-section facing the through hole is formed with the same shape as the through hole,
The end of the fastening rod having a cross-section projecting from the end surface in the moving direction through the through hole of the multipole field magnetic pole is fitted in the hole of the nonmagnetic holder. the characteristics and to Ruri linear motors. 3. The linear motor according to claim 2 , wherein a cross-sectional shape of the through hole of the multipole field magnetic pole, the hole of the nonmagnetic holder, and the fastening rod is a four to hexagonal shape. The non-magnetic holder includes a first holder in which the hole into which one end portion of the fastening rod is fitted, and a second holder in which the hole into which the other end portion of the fastening rod is fitted is formed. The linear motor according to any one of claims 1 to 3 , wherein the first and second holders are fastened together by a fastening member. The linear motor according to any one of claims 1 to 4 , wherein a spacer is provided between the main magnetic pole permanent magnet and the auxiliary magnetic pole permanent magnet. Wherein a moving direction of the length of the multi Kyokukai magnetized poles, the non-magnetic holder, in claim 5, characterized in that the said longer than the moving direction of the length of the hole multi Kyokukai magnetizing magnetic poles are fitted The linear motor described.

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