JP2014180102A - Rotator and permanent magnet motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rotator capable of cooling a corner of a permanent magnet when the rotator is rotated, and a permanent magnet motor using the rotator.SOLUTION: A rotator 1 comprises non-magnetic end plates 20 arranged on both end faces in a rotation axial direction of a columnar rotor iron core 10, and plate-like permanent magnets 40 are respectively embedded in plural magnet embedding holes annularly formed at predetermined intervals near an outer periphery of the rotator iron core 10 and extending in the rotation axial direction so that each of the plural magnet embedding holes serves as a side forming a polygon centering on a rotation shaft of the rotor iron core 10. The end plate 20 comprises: a magnet detachment-prevention part 200 contacting the rotator iron core 10 across centers of the magnet embedding holes faced to the ends in the rotation axial direction of the rotator iron core 10 in a radial direction, and preventing the permanent magnet 40 from being detached from the rotator iron core 10; and a blade part 210 projecting in the rotation axial direction so as to expose corners 400 of the permanent magnets 40 faced to the end face in the rotation axial direction of the rotator iron core 10.

Description

  The present invention relates to a rotor and a permanent magnet electric motor using the rotor.

  2. Description of the Related Art Conventionally, a permanent magnet motor mounted on a compressor or the like includes a stator having a stator winding and a rotor arranged at an interval on the inner diameter side of the stator, and the rotor has an inner part of the rotor core. A permanent magnet is embedded in a magnet embedding hole formed in the above and extending in the direction of the rotation axis. During operation of the permanent magnet motor, when current flows through the stator winding and magnetic flux is generated, an eddy current is generated in the permanent magnet due to the armature reaction generated in the stator winding. The permanent magnet self-heats due to this eddy current and the temperature rises, so that the magnetic flux of the magnet decreases (demagnetization).

  As a rotor that solves the problem that the magnetic flux of the permanent magnet is reduced due to the temperature rise of the permanent magnet, the outer peripheral side surface of the permanent magnet is in close contact with the magnet embedding hole with respect to the rotation center of the rotor. Some peripheral side surfaces have cooling passages through which the refrigerant flows along the magnet embedding holes (see, for example, Patent Document 1). By cooling the permanent magnet by flowing the refrigerant when the rotor rotates in the cooling passage, it is possible to suppress a decrease in the magnetic flux of the permanent magnet. However, in the technique of Patent Document 1, the permanent magnet can be cooled by the cooling passage formed along the magnet embedding hole on the inner peripheral side surface of the permanent magnet. There is a problem that the corner portions of the easy permanent magnets cannot be cooled effectively.

JP 2002-345188 A

  An object of this invention is to provide the rotor which can cool the corner | angular part of a permanent magnet when rotating a rotor, and the permanent magnet electric motor using the rotor in view of the said problem.

  In order to solve the above problems, a rotor of the present invention includes a cylindrical rotor core and non-magnetic end plates disposed on both end surfaces in the rotation axis direction of the rotor core. Plate-like permanent magnets are formed in a plurality of magnet embedded holes extending in the direction of the rotation axis that are annularly formed at predetermined intervals near the outer periphery of the rotor core so as to form polygonal sides centered on the rotation axis. The end plate is in contact with the rotor core so as to straddle the central portion of the magnet embedding hole facing the end surface in the rotation axis direction of the rotor core in the radial direction, and is permanent from the rotor core. A magnet drop-off preventing portion that prevents the magnet from falling off, and a blade portion that protrudes in the rotation axis direction so as to expose a corner portion of the permanent magnet facing the end surface in the rotation axis direction of the rotor core.

  The permanent magnet motor of the present invention includes the above-described rotor and a stator that is arranged to face the outer diameter side of the rotor at a predetermined interval.

  According to the rotor of the present invention and the permanent magnet motor using the rotor, the end plate has a central portion of the magnet embedding hole in which the magnet dropout prevention portion faces the end surface in the rotation axis direction of the rotor core in the radial direction. Abuts against the rotor core so as to straddle so that the permanent magnet does not fall out of the rotor core, and the blade part protrudes in the direction of the rotation axis so that the corner of the permanent magnet facing the end surface of the rotor core in the rotation axis direction is exposed. To do. For this reason, when the rotor is rotated, the air remaining between the blade portions corresponding to each of the adjacent permanent magnets is pushed out to the outside of the rotor core by centrifugal force, and is removed from the inner diameter side of the rotor core. An air flow through the exposed surface of the corner portion of the permanent magnet is generated toward the radial side. As a result, it is possible to cool the corners of the permanent magnet that has become hot due to concentration of eddy currents due to the skin effect.

It is a disassembled perspective view which shows the rotor of this invention. It is an external appearance perspective view which shows the rotor of this invention. It is a top view which shows the permanent magnet electric motor using the rotor of this invention. It is a top view which shows other embodiment of the end plate with which the rotor of this invention was equipped.

  Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIGS. 1 to 4 are views for explaining a permanent magnet motor mounted on a rotor and a compressor using the rotor in the present embodiment. As shown in FIGS. 1 and 2, the rotor 1 includes a rotor core 10, an end plate 20, a rivet 30, and a permanent magnet 40. The rotor core 10 is formed in a cylindrical shape by laminating a plurality of thin magnetic steel plates, and a rotation shaft (not shown) is inserted and fixed at the center thereof. The rotor core 10 includes six rectangular magnet embedding holes 100 formed annularly at predetermined intervals on the outer periphery so as to form hexagonal sides centered on the rotation axis, and the magnet embedding holes. Six circular through-holes 110 formed annularly at predetermined intervals closer to the inner periphery than the insertion holes 100 are provided.

  The magnet embedding hole 100 is a through hole having a side extending in the circumferential direction longer than a side extending in the radial direction of the rotor core 10 and extending in the rotation axis direction, and has six plate-like permanent shapes extending in the rotation axis direction. Magnets 40 are respectively embedded. The six permanent magnets 40 embedded in the magnet embedding hole 100 are arranged so that adjacent magnetic poles are different from each other. The through-hole 110 is a hole extending in the direction of the rotation axis similarly to the magnet embedding hole 100, and the rod-like rivets 30 extending in the direction of the rotation axis are inserted into three of them. The other three through holes 110 are used, for example, when fixing the position of the rotor core 10 to a magnetizing jig (not shown) for magnetizing the rotor core 10.

  The end plate 20 is formed in a ring shape by processing a thin sheet metal made of a non-magnetic material, and is disposed on the upper end surface 120 and the lower end surface 130 which are both end surfaces in the rotation axis direction of the rotor core 10. The end plate 20 disposed on the upper end surface 120 includes a magnet dropout prevention unit 200, a blade unit 210, and a blade coupling unit 220. The magnet drop-off prevention part 200, the blade part 210, and the blade connecting part 220 are each integrally formed in an annular shape extending from the inner diameter side to which the rotating shaft of the rotor core 10 is fixed to the outer diameter side. Are arranged in this order: part 210, magnet dropout prevention part 200, blade part 210, blade connecting part 220, blade part 210,. Note that the end plate 20 disposed on the lower end surface 130 has the same configuration as the end plate 20 disposed on the upper end surface 120, and thus detailed description thereof is omitted.

  The magnet dropout prevention unit 200 rotates so as to straddle the respective central portions 101 of the upper end opening and the lower end opening of the magnet embedding hole 100 facing the upper end surface 120 and the lower end surface 130 in the rotation axis direction of the rotor core 10. The permanent magnet 40 is brought into contact with the core 10 so that the permanent magnet 40 does not fall out from the magnet embedding hole 100 of the rotor core 10 in the direction of the rotation axis. The blade portion 210 rotates the rotor core 10 from both sides of the magnet dropout prevention portion 200 so as to expose the corner portions 400 of the permanent magnet 40 facing the upper end surface 120 and the lower end surface 130 in the rotation axis direction of the rotor core 10. Projects in the axial direction. The blade connecting portion 220 connects the upper ends of the blade portions 210 corresponding to the adjacent permanent magnets 40 to form a space so as to surround the corner portions 400 of the adjacent permanent magnets.

  The magnet dropout prevention unit 200 is formed with a circular insertion hole 201 at a position corresponding to the through hole 110 of the rotor core 10, and the insertion hole 201 fixes the end plate 20 to the stator core 10 through the rivet 30. It is a hole for. Further, the blade connecting portion 220 is formed with a circular vent hole 221 near the inner diameter side of the rotor core 10, and the vent hole 221 is removed from the inner diameter side of the rotor core 10 when the rotor 1 is rotated. It is a hole for passing air toward the radial side. In the air holes 221, the air remaining in the spaces formed by the blade portions 210 and the blade connecting portions 220 corresponding to the adjacent permanent magnets 40 is pushed out of the rotor core 10 by the centrifugal force generated by the rotation of the rotor 1. Air can pass through.

  The procedure for assembling the rotor 1 configured as shown in FIG. 2 will be described with reference to FIG. As shown in FIG. 1, each end has a through hole 110 visible from the upper end surface 120 of the rotor core 10 into which the permanent magnet 40 before magnetization is inserted, and a through hole 110 visible from the lower end surface 130 of the rotor core 10. The insertion hole 201 formed in the magnet dropout prevention part 200 of the plate 20 is aligned. Thereafter, three rivets 30 are respectively inserted from the insertion holes 201 of the end plate 20 disposed on the lower end surface 130 of the rotor core 10, and the rivets 30 are rotated through the through holes 110 of the rotor core 10. The tip portions 300 of the rivets 30 are projected from the insertion holes 201 of the end plate 20 disposed on the upper end surface 120 of the core 10.

  Next, the tip 300 of the rivet 30 is caulked and plastically deformed (collapsed) by repeatedly pressing and rotating the head pin (not shown) of the rivet 30 with a head pin (not shown). In order to rotate and move the head pin of the caulking machine, as shown in FIG. 1, the blade portions 210 protruding in the direction of the rotation axis from both sides of the magnet dropout prevention portion 200 are radially extended so as to spread outward. It is arranged to secure a movable space for the head pin of the caulking machine. As a result, as shown in FIG. 2, the rotor 1 in which the end plate 20 is fixed to the upper end surface 120 and the lower end surface 130 of the rotor core 10 is assembled.

  As shown in FIG. 3, the permanent magnet motor M includes the rotor 1 and the stator 5 described above. The stator 5 includes a stator core 50, an insulator 60, and a stator winding 70. The stator core 50 is formed on a cylinder by laminating a plurality of thin steel plates, and includes an annular back yoke portion 500 and a plurality of teeth portions 510 extending from the back yoke portion 500 to the inner diameter side. An insulator 60 is integrally formed on the stator core 50 by molding, and the stator winding 70 is wound around the tooth portion 510 via the insulator 60. The stator 5 configured as described above is arranged such that the tip surface of the tooth portion 510 faces the outer diameter side of the rotor 1 with a predetermined interval (so-called air gap). Further, the upper end portion and the lower end portion (so-called coil end) in the rotation axis direction of the stator winding 70 are arranged so as to face the end plates 20 fixed to the upper end surface 120 and the lower end surface 130 of the rotor core 10, respectively. ing.

  According to the rotor 1 and the permanent magnet motor M using the rotor 1 according to the embodiment described above, the blade portion 210 of the end plate 20 has the upper end surface 120 and the lower end surface in the rotation axis direction of the rotor core 10. 130 from both sides of the magnet dropout prevention portion 200 for preventing the permanent magnet 40 from falling out of the magnet embedding hole 100 so as to expose the corner portion 400 of the permanent magnet 40 facing 130. It protrudes. Further, the blade portions 210 corresponding to the adjacent permanent magnets 40 are connected to each other by the blade connecting portion 220, and a ventilation hole 221 is formed near the inner diameter side of the rotor core 10 of the blade connecting portion 220.

  For this reason, when the rotor 1 is rotated, the air remaining in the space formed by the blade portions 210 and the blade connecting portions 220 corresponding to the adjacent permanent magnets 40 is outside the rotor core 10 by centrifugal force. Extruded. Therefore, as indicated by an arrow a shown in FIG. 2, air is taken in from the vent hole 221 of the blade connecting portion 220 so that an air flow from the inner diameter side to the outer diameter side of the rotor core 10 is generated. it can. Thereby, the corner | angular part 400 of the permanent magnet 40 in which the eddy current concentrated by the skin effect and became high temperature can be cooled. Further, since the air can be blown toward the stator winding 70 disposed so as to face the end plate 20, the stator winding 70 that generates heat when current flows can be effectively cooled. Thus, by cooling the permanent magnet 40 and the stator winding 70, the permanent magnet 40 is reduced in magnet magnetic flux due to self-heating, or the stator winding 70 generates heat, thereby increasing the winding resistance. Thus, it is possible to suppress the motor efficiency from decreasing.

  Next, an end plate 80 according to another embodiment will be described with reference to FIGS. In addition, the same code | symbol is attached | subjected about the same structure as the above-mentioned embodiment, and the description is abbreviate | omitted. As shown in FIG. 1 and FIG. 4, the end plate 80 includes a magnet dropout prevention portion 800 and a blade portion 810. The magnet dropout prevention portion 800 rotates so as to straddle the respective central portions 101 of the upper end opening and the lower end opening of the magnet embedding hole 100 facing the upper end surface 120 and the lower end surface 130 in the rotation axis direction of the rotor core 10. The permanent magnet 40 is brought into contact with the core 10 so that the permanent magnet 40 does not fall out from the magnet embedding hole 100 of the rotor core 10 in the direction of the rotation axis. The blade portion 810 has corner portions of the permanent magnet 40 from both sides of the magnet dropout prevention portion 800 so as to expose the corner portions 400 of the permanent magnet 40 facing the upper end surface 120 and the lower end surface 130 of the rotor core 10 in the rotation axis direction. It is formed by raising a portion facing 400. In the end plate 80, a circular insertion hole 820 is formed at a position corresponding to the through hole 110 of the rotor core 10, closer to the inner diameter side of the rotor core 10 than the magnet dropout prevention portion 800. The rivet 30 passes through and the end plate 80 is fixed to the stator core 10.

  As a result, when the rotor 1 is rotated as in the above-described embodiment, the corner portions 400 of the permanent magnet 40 and the air come into contact with each other. The corner 400 can be cooled. Further, if the blade portion 810 is cut and raised so that wind is generated from the inner diameter side to the outer diameter side of the end plate 80, the stator winding 70 can be cooled. Furthermore, since the shape is simple compared to the end plate 20 of the above-described embodiment, the end plate 80 can be easily processed.

DESCRIPTION OF SYMBOLS 1 Rotor 10 Rotor core 100 Magnet embedding hole 101 Center part 110 Through-hole 120 Upper end surface 130 Lower end surface 20, 80 End plate 200,800 Magnet drop-off prevention part 201,820 Insertion hole 210,810 Blade part 220 Blade connection part 221 Vent 30 Rivet 300 Tip 40 Permanent Magnet 400 Corner 5 Stator 50 Stator Core 500 Back Yoke 510 Teeth 60 Insulator 70 Stator Winding M Permanent Magnet Motor

Claims (4)

A cylindrical rotor core and non-magnetic end plates disposed on both end faces in the rotation axis direction of the rotor core, each side of the polygon centering on the rotation axis of the rotor core A rotor in which plate-like permanent magnets are embedded in a plurality of magnet embedding holes extending in the direction of the rotation axis formed annularly at a predetermined interval near the outer periphery of the rotor core,
The end plate is in contact with the rotor core so as to straddle the central portion of the magnet embedding hole facing the end surface in the rotation axis direction of the rotor core, and the permanent magnet does not fall out of the rotor core. A rotor comprising: a magnet fall-off prevention portion to be made; and a blade portion protruding in the rotation axis direction so as to expose a corner portion of the permanent magnet facing the end surface in the rotation axis direction of the rotor core. .   The rotor according to claim 1, wherein the end plate includes a blade connecting portion that connects the blade portions corresponding to each of the adjacent permanent magnets.   The rotor according to claim 2, wherein the blade connecting portion is formed with a vent hole.   A permanent magnet electric motor comprising: the rotor according to any one of claims 1 to 3; and a stator arranged to face the outer diameter side of the rotor at a predetermined interval.