JP2009261162A - Split stator core - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a split stator core, having less iron loss and higher motor efficiency by forming a stress-relaxing hole at a position considered most effective for reducing the compression stress at a yoke part. <P>SOLUTION: A plurality of split stator cores 10 constitute a stator core assembly which is formed into a circular form, by clamping and assembling from outside along radial direction. A yoke part 14, divided in circumferential direction, is provided to constitute a part of the circle. In an assemble state where both end faces 24 in circumferential direction of the yoke part 14 are press-contacted to end faces 24 in the circumferential direction of an adjoining split stator core, a stress relaxing hole 32 is so formed as to split, in the length direction of region, a high compression stress region in which a higher compression stress can occur than in the other region, in the end part region 30 in circumferential direction of the yoke part 14. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a split stator core, and more particularly to a plurality of split stator cores that constitute an annular assembly stator core by being assembled by being tightened from the outside in the radial direction.

  Conventionally, a permanent magnet type synchronous motor is used as a driving force source for a hybrid vehicle or the like. The stator core constituting the motor is not integrally molded, and a plurality of divided stator cores are arranged in an annular shape, and then an annular fixing member is shrink-fitted or press-fitted from the outer periphery thereof in the radially outer side. An annular assembly stator core is known which is assembled by tightening from the above.

  In such an assembled stator core, compressive stress is generated inside the divided stator core after assembly, which causes problems such as an increase in iron loss and a decrease in motor efficiency due to a decrease in magnetic flux density. For this reason, various proposals have been made to reduce internal stress during assembly of the split stator core.

  For example, Patent Document 1 discloses that a split stator core that is adjacent when a projection is formed on the radially outermost end surface (split surface) of a yoke portion having an arc shape in the split stator core and assembled into an annular stator core. Thus, a gap is formed between the circumferential end surfaces of the yoke portion excluding the protruding portion forming portion in the connecting portion of the divided stator core. As a result, the compressive stress is localized only in the radially outermost peripheral portion of the yoke portion so that the compressive stress is not applied to the main magnetic flux region of the yoke portion, thereby reducing the iron loss and increasing the efficiency of the motor. Yes.

JP 2005-51941 A

  However, in the split stator core of Patent Document 1, the gap formed between the adjacent split stator cores is configured as a space or gap having a low permeability compared to a ferromagnetic material such as iron or iron alloy that is a stator core constituent material. Therefore, the decrease in magnetic flux density due to the fact that this gap is formed across the main magnetic flux region cannot be denied.

  An object of the present invention is to provide a split stator core capable of reducing iron loss and improving motor efficiency by forming stress relaxation holes at positions considered to be most effective for reducing compressive stress in the yoke portion of the split stator core. An object of the present invention is to provide an assembled stator core and a rotating electric machine using the same.

  A split stator core according to an aspect of the present invention is a plurality of split stator cores that are assembled by being tightened from outside in the radial direction to form an annular assembled stator core, and the split stator core forms a part of the ring. In the assembled state in which both end surfaces in the circumferential direction of the yoke portion are pressed against the circumferential end surfaces of the adjacent divided stator cores in the circumferential end region of the yoke portion as compared with other regions. A stress relaxation hole is formed at a position where a high compressive stress region where high compressive stress can be generated is divided in the longitudinal direction of the region.

  The split stator core according to the present invention further includes a teeth portion that protrudes radially inward from the circumferential central portion of the yoke portion so that the coil is disposed on the outer periphery, and is adjacent to each other when a current flows through the coil. A stress relaxation hole may be extended and formed so as to substantially follow a magnetic path formed through one end of the yoke portion in the circumferential direction from one tooth portion to the other tooth portion.

  In the split stator core according to the present invention, the stress relaxation hole may be formed in a slit shape extending in a direction intersecting the longitudinal direction of the high compressive stress region.

  In the split stator core according to the present invention, a plurality of stress relaxation holes may be formed at intervals in the longitudinal direction of the high compressive stress region.

  In the split stator core according to the present invention, the stress relaxation hole may be formed so as to be inclined so that the end portion on the yoke portion center side is positioned radially inward with respect to the end portion on the yoke portion end face side in the circumferential direction. Good.

  Further, the split stator core according to another aspect of the present invention is a plurality of split stator cores constituting an assembly stator core that is tightened and assembled from the outside in the radial direction, and the split stator core is a part of the ring. The yoke portion has a yoke portion that is divided in the circumferential direction so as to form one or more, and one or a plurality of stress relaxation holes are formed in the yoke portion in the circumferential end region and in the central region in the thickness direction along the radial direction of the ring It is characterized by being. In this case, it is preferable that the stress relaxation hole is formed in a slit shape that is inclined so that the end portion on the yoke portion center side is positioned radially inward with respect to the end portion on the yoke portion end face side in the circumferential direction.

  The assembled stator core according to the present invention is assembled by arranging any of the above-mentioned divided stator cores in an annular shape and tightening them from the radially outer side by an annular fixing member arranged on the outer periphery thereof.

  Furthermore, a rotating electrical machine according to the present invention includes the assembly stator core, and a rotor that is disposed in the assembly stator core so as to be rotatable around a rotation axis, and a plurality of permanent magnets are fixed to an outer peripheral portion. is there.

  According to the divided stator core, the assembled stator core, and the rotating electric machine according to the present invention, the high compressive stress region in which the compressive stress higher than the other regions can be generated in the circumferential end region of the yoke portion in the assembled state is related to the longitudinal direction of the region. The stress relaxation hole is formed in the position to be divided (in other words, the circumferential end region and the thickness direction central region along the annular diameter direction), so that the compression stress in the divided stator core is most effectively reduced. As a result, it is possible to reduce the iron loss and increase the efficiency of the rotating electrical machine.

  Embodiments according to the present invention will be described below in detail with reference to the accompanying drawings. The following embodiments can be applied to a motor generator (rotary electric machine) mounted on a hybrid vehicle, but electric vehicles such as fuel cell vehicles and electric vehicles other than hybrid vehicles, industrial devices, air conditioning devices, and the like The present invention can also be applied to rotating electrical machines mounted on various devices. In the following description, specific shapes, materials, numerical values, directions, and the like are examples for facilitating understanding of the present invention, and can be appropriately changed according to the use, purpose, specification, and the like. .

  FIG. 1 is a plan view showing a main part of a motor (rotary electricity) 1 configured using a divided stator core 10 according to an embodiment of the present invention. The motor 1 has an assembly stator core 12 having an annular shape. The assembled stator core 12 includes a plurality of divided stator cores 10 arranged in an annular shape.

  The split stator core 10 is made of a magnetic material such as iron or an iron alloy, and is assembled with a yoke portion 14 that forms a part of an annulus when assembled, and a radially inner side from the central portion of the inner surface of the yoke portion 14. And a teeth portion 16 projecting from the teeth. A slit-like stress relaxation hole 32 is formed in the circumferential end region of the yoke portion 14, which will be described in detail later.

  The distal end surface 18 on the radially inner side of the tooth portion 16 is formed as an arcuate surface that curves in a concave shape. On the outer periphery of the tooth portion 16, a coil (not shown) formed by winding an armature conductor before being assembled as the assembled stator core 12 is disposed. Rather than arranging or winding the coil on the tooth portion 16 of each divided stator core 10 in the state of the assembled stator core 12, it is better to arrange or wind the coil on the tooth portion 16 of the divided stator core 10 that is in a separated state. The arrangement | positioning etc. can be performed easily.

  First, as shown in FIG. 2, the plurality of split stator cores 10 are arranged in an annular shape with the circumferential end surfaces of the split stator cores 10 in contact with each other. Then, as shown in FIG. 3, a cylindrical internal mold 7 having an outer peripheral surface shape substantially along the tip surface 18 of the tooth portion 16 of each divided stator core 10 is inserted and disposed on the inside thereof. Then, an annular or cylindrical fixing member 20 is attached to the outer periphery of each divided stator core 10 arranged in an annular shape by a method such as shrink fitting or press fitting. Thereby, each divided stator core 10 is pressed radially inward, and is tightened so that the front end surface 18 of each tooth portion 16 is in pressure contact with the outer peripheral surface of the internal mold 7, whereby the assembled stator core 12 is assembled. It is done. After assembly, the internal mold 7 is removed.

  Referring to FIG. 1 again, a cylindrical rotor 2 is disposed inside the assembled stator core 12. The rotor 2 is made of a magnetic material such as iron or iron alloy, and has a rotor core 3 formed by laminating a plurality of electromagnetic steel plates, and a plurality of permanent magnets 4 fixed to the outer periphery of the rotor core 3. ing. The rotor 2 is supported so as to be rotatable around a rotating shaft 5 that is coaxial with the annular central shaft 6 of the assembled stator core 12 and protrudes from the rotor end surface. As a result, in the motor 1, the rotor 2 is rotated by the magnetic flux generated between the rotor 2 and the assembled stator core 12 when a current is supplied from the power source to the coils of each divided stator core 10 via the inverter or the like. .

  FIG. 1 illustrates an SPM (Surface Permanent Magnet) in which the permanent magnet 4 is exposed and fixed on the outer peripheral surface of the rotor core 3. However, the present invention is not limited to this, and the permanent magnet is disposed in the vicinity of the outer periphery of the rotor core 3. May be an IPM (Interior Permanent Magnet) in which is embedded.

  Next, the split stator core 10 will be described in detail with reference to FIGS.

  As shown in FIG. 4, the split stator core 10 is formed so that the yoke portion 14 and the teeth portion 16 are substantially T-shaped. The outer circumferential surface 22 on the radially outer side of the yoke portion 14 has an arc shape so as to constitute a part of the outer circumferential surface of the assembly stator core 12 that forms an annular shape. Further, the end surface 24 in the circumferential direction of the yoke portion 14 is formed so as to coincide with a plane including the annular central axis 6 of the assembly stator core 12 forming an annular shape, and the entire surface thereof is assembled when the assembly stator core 12 is assembled. Is in pressure contact with the circumferential end surface 24 of the adjacent divided stator core 10.

  As described above, the tooth portion 16 projecting radially inward from the inner circumferential surface of the yoke portion 14 has the tip surface 18 formed as an arcuate surface, and each side surface 26 in the circumferential direction has an annular central axis 6. It is formed as a taper surface that tapers.

  End regions 30 (hereinafter referred to as “circumferential end regions” as appropriate) of the yoke portion 14 protrude from the base end portion of the tooth portion 16 to both sides in the circumferential direction. Three stress relaxation holes 32 each formed of an elongated rectangular slit are formed in the circumferential end region 30 of the yoke portion 14. These stress relaxation holes 32 are arranged at appropriate intervals along a force direction line, which will be described later, and the circumference of the yoke portion 14 is larger than the end portion 32a on the circumferential end face 24 side of the yoke portion 14 in the circumferential direction. The end portion 32b on the central side in the direction is inclined and formed so as to be located on the radially inner side. Further, as will be described later, in order to suppress the increase in magnetic resistance as much as possible by reducing the cross-sectional area that becomes the magnetic path (that is, the path of the lines of magnetic force) in the end region 30 of the yoke portion 14, The total of the widths w in the short side direction (that is, 3w) is preferably about 1/10 of the radial thickness of the yoke portion 14.

  Here, with reference to FIG. 5 and 6, the position and shape which form the said stress relaxation hole 32 are demonstrated. After the inventors of the present invention assembled the divided stator cores 11 having no stress relaxation holes in an annular shape to form an assembled stator core, the distribution state of the compressive stress in each divided stator core 15 was analyzed based on the stress contour. Then, as shown in FIG. 5, in the yoke portion end region 31, the yoke portion outer peripheral surface 23 is located from the vicinity of the radially inner edge portion 27 of the circumferential end surface 25 toward the yoke portion circumferential center of the yoke portion end region 31. It has been found that there is a substantially oval high compressive stress region 34 in which a compressive stress higher than that in the other regions of the yoke portion 15 is generated in the region extending in the vicinity of. An action direction of the compressive stress in the high compressive stress region 34 is represented by a force direction line 36 that extends through the center of the substantially oval high compressive stress region 34 in the longitudinal direction.

  Based on such knowledge, in the divided stator core 10 of the present embodiment, the high compressive stress region 34 intersects the force direction line 36 at a position where the high compressive stress region 34 is divided at a plurality of locations in the longitudinal direction. Slit-like stress relaxation holes 32 are formed at positions that cross the region 34 at a plurality of locations. Thereby, if there is no stress relaxation hole, the compressive stress can be most effectively reduced or reduced in the end region 30 of the yoke portion 14 where the high compressive stress region 34 can be generated. Reduction and high efficiency of the motor 1 can be achieved.

  Further, as described above, in the stress relaxation hole 32 in the present embodiment, the end portion 32b on the circumferential center side of the yoke portion 14 is radially inward with respect to the circumferential end surface 24 side of the yoke portion 14 in the circumferential direction. Inclined and formed so as to be located in As shown in FIG. 6, the slit-shaped stress relaxation hole 32 is formed so as to be inclined, as shown in FIG. 6. In the assembled stator core 12, a current is passed to the coil disposed on the outer periphery of the tooth portion 16 of the divided stator core 10. Sometimes between two adjacent stator cores 10 so as to be substantially along the magnetic path 38 formed through the circumferential end region 30 of the yoke portion 14 from one tooth portion 16 to the other tooth portion 16. is there. Thereby, the stress relaxation hole 32 including a space having a smaller magnetic permeability than that of the magnetic material is prevented from crossing the magnetic path 38 as much as possible, so that a decrease in magnetic flux density due to the stress relaxation hole 32 can be suppressed, and the motor 1 can contribute to higher efficiency.

  Although the split stator core 10 according to the embodiment of the present invention has been described above, the split stator core according to the present invention is not limited to this, and various modifications and improvements can be made without departing from the technical scope of the present invention. Is possible.

  For example, in the above description, an example in which three stress relaxation holes 32 are formed in the end region 30 of the yoke portion 14 has been described. However, the number of the stress relaxation holes may be two or more than four. Alternatively, there may be only one. In order to make the stress relaxation in the high compressive stress region that can occur in the end region of the yoke part more effective in the case where there is one or a plurality of stress relaxation holes, the center in the longitudinal direction of the high compressive stress region Preferably, one or a plurality of stress relaxation holes are formed in the central region in the region, in other words, in the thickness direction of the yoke portion along the radial direction.

  Further, the stress relaxation hole is not limited to an elongated rectangular shape, and may be, for example, a curved slit shape as shown in FIG.

  Further, when a plurality of stress relaxation holes are formed in the end region of the yoke portion, the stress relaxation holes may be formed to have different sizes such as width and length.

It is a top view which shows the principal part of the motor using the division | segmentation stator core which is one Embodiment of this invention. It is a top view which shows the state which arranged the division | segmentation stator core in the annular | circular shape. It is a top view which shows the state when assembling an assembly stator core. It is an enlarged plan view of a divided stator core. It is a figure which shows the high compressive-stress area | region which generate | occur | produces about the division | segmentation stator core in which the stress relaxation hole is not formed. It is a figure which shows that the stress relaxation hole is formed along the magnetic path which generate | occur | produces between two adjacent division | segmentation stator cores. It is a figure which shows the modification of a stress relaxation hole.

Explanation of symbols

  1 Motor, 2 Rotor, 3 Rotor Core, 4 Permanent Magnet, 5 Rotating Axis, 6 Ring Center Axis, 7 Internal Mold, 10 Split Stator Core, 12 Assembly Stator Core, 14 Yoke Part, 16 Teeth Part, 18 Tip Surface, 20 Fixed Member, 22 outer peripheral surface, 24 circumferential end surface, 26 side surface, 30 end region, 32 stress relaxation hole, 34 high compressive stress region, 36 force direction line, 38 magnetic path.

Claims (9)

A plurality of divided stator cores constituting an assembly stator core that is formed by being tightened and assembled from the outside in the radial direction,
The split stator core has a yoke portion that is divided in the circumferential direction so as to form a part of the ring, and the yoke in an assembled state in which both end surfaces in the circumferential direction of the yoke portion are respectively pressed against the circumferential end surfaces of the adjacent divided stator cores. A split stator core characterized in that stress relaxation holes are formed at positions where a high compressive stress region in which a higher compressive stress than other regions can be generated in a circumferential end region of the portion is divided in the longitudinal direction of the region. The split stator core according to claim 1,
The tooth portion further protrudes radially inward from the inner surface of the central portion in the circumferential direction of the yoke portion and the coil is disposed on the outer periphery, and one of the tooth portions between two adjacent divided stator cores when current flows through the coil A split stator core, wherein stress relaxation holes are formed to extend substantially along a magnetic path formed through one end of the yoke portion in the circumferential direction from the other tooth portion to the other tooth portion. The split stator core according to claim 1 or 2,
The split stator core, wherein the stress relaxation hole is formed in a slit shape extending in a direction intersecting with a longitudinal direction of the high compressive stress region. The split stator core according to any one of claims 1 to 3,
A split stator core, wherein a plurality of stress relaxation holes are formed at intervals in the longitudinal direction of the high compressive stress region. In the split stator core according to any one of claims 1 to 4,
The split stator core is characterized in that the stress relaxation hole is formed so as to be inclined so that the end portion on the yoke portion center side is positioned radially inward with respect to the end portion on the yoke portion end face side in the circumferential direction. A plurality of divided stator cores constituting an assembly stator core that is formed by being tightened and assembled from the outside in the radial direction,
The split stator core has a yoke portion that is divided in the circumferential direction so as to form a part of the ring, and the yoke portion is a circumferential end region in a central region in the thickness direction along the radial direction of the ring. A divided stator core, wherein one or a plurality of stress relaxation holes are formed. The split stator core according to claim 6,
The split stator core is characterized in that the stress relaxation hole is formed in a slit shape that is inclined so that the end portion on the center side of the yoke portion is located radially inward relative to the end portion on the end surface side of the yoke portion in the circumferential direction.   An assembled stator core assembled by arranging the divided stator cores according to any one of claims 1 to 7 in an annular shape and tightening the annular stator members from the outside in a radial direction by an annular fixing member disposed on an outer periphery thereof. An assembled stator core according to claim 8;
A rotor that is rotatably arranged around a rotation axis in an assembly stator core, and a plurality of permanent magnets are fixed to the outer periphery;
A rotating electrical machine.

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