JP2016127642A - Rotary electric machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make suppression of deformation of a rotor core accompanied in injection molding of bond magnets compatible with suppression of increase of magnetic flux leakage and suppression of increase in the number of charging gates.SOLUTION: A rotary electric machine comprises a rotor (11) including a plurality of magnets (100) and a rotor core (101), and a stator (12) into which the rotor (11) is inserted. The magnet (100) is a bond magnet filled in a magnet slot (S100) that is a hole axially penetrating the rotor core (101), and includes a center part (21) which protrudes radially outside of the rotor (11), and two side parts (31 and 31) which symmetrically extend from the radial inside of the center part (21) while being separated from each other. On a cross section, the magnet (100) is surrounded by the rotor core (101), a width d1 of the center part (21) in a circumferential direction is greater than a width d2 of the side part (31) in a radial direction, and the side parts (31) of the magnets (100) neighboring to each other are separated by a boundary part (111) that is a part of the rotor core (101), at a distance shorter than or equal to d2.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a rotating electrical machine.

  Conventionally, in a process of manufacturing a rotor of a rotating electric machine such as an electric motor or a generator, a molten resin containing magnetic powder is injected into a magnet slot formed in the rotor core and solidified (that is, injection molding). It is known to fill a magnet slot of a rotor core with a bond magnet (for example, Patent Document 1).

JP 2014-57392 A

  A rotary electric machine according to Patent Document 1 includes a rotor having a rotor core in which a plurality of magnet slots are formed, and a stator through which the rotor is inserted, and each of the plurality of magnet slots is formed on both side wall portions by a pair of bridge portions. And a pair of outer slot portions that open from the pair of bridge portions to the outer edge of the rotor core, and the inner slot portion and the pair of outer slot portions are filled with bond magnets. The purpose is to suppress the deformation of the rotor core due to the injection molding of the bond magnet, but since there is a pair of bridge parts, the leakage of magnetic flux increases and the gate for filling the bond magnet is inside There is a problem that the number of slots and the number of outer slots need to be increased.

  The present invention has been made in view of such a point, and the object thereof is to suppress the deformation of the rotor core accompanying the injection molding of the bond magnet, to suppress the increase in magnetic flux leakage, and to suppress the increase in the number of filling gates. An object of the present invention is to provide a rotating electrical machine capable of achieving both of the above.

  A first invention includes a rotor (11) having a plurality of magnets (100) and a rotor core (101), and a stator (12) through which the rotor (11) is inserted, and the magnet (100) A bond magnet filled in a magnet slot (S100) which is a hole penetrating the rotor core (101) in the axial direction, and a center portion (21) protruding outward in the radial direction of the rotor (11); , And two side portions (31, 31) extending in a symmetrical shape from the inside in the radial direction of the center portion (21), and in the cross section, the periphery of the magnet (100) is the rotor core ( 101), a width d1 along the circumferential direction of the center portion (21) is larger than a width d2 along the radial direction of the side portion (31), and the adjacent magnets (100) are adjacent to each other. The side portions (31) are boundary portions that are part of the rotor core (101). By 111) is a rotating electric machine, characterized in that are separated by a distance of the d2 below. The fact that the side portions (31, 31) extend in a symmetrical shape means that the side portions (31, 31) extend in a symmetrical shape with respect to the diameter of the rotor passing through the center portion.

  In the first invention, the boundary portion (111) functions to pull the portion of the rotor core (101) located outside the magnet slot (S100) in the direction of the central axis during the injection molding of the bonded magnet.

  According to a second aspect of the present invention, in the first aspect of the invention, the d1 is at least twice as large as the d2.

  In the second aspect of the invention, the thickness of the center portion (21) is increased to increase the magnetoresistance of this portion.

  According to a third aspect of the present invention, in the first or second aspect of the invention, the boundary portion (111) is located at a substantially equal distance from the center portions (21) of the adjacent magnets (100). It is. The approximately equal distance is not an equal distance in a mathematically strict sense, but means that a distance deviation or error that does not impede practically in the production and operation of a rotating electrical machine is allowed. ing.

  In the third invention, adjacent magnets (100, 100) have a line-symmetric shape with the boundary (111) as the axis of symmetry.

  A fourth invention is the rotary electric machine according to any one of the first to third inventions, wherein the bond magnet is filled from a filling gate located on the center portion (21).

  In the fourth aspect of the invention, the position of the filling gate is located in the central portion of the magnet slot (S100) in the cross section.

  According to 1st invention, the magnet (100) is provided with the center part (21) and the side part (31), the boundary part (111) exists between adjacent magnets (100), and Since d1> d2, it is possible to achieve both suppression of deformation of the rotor core (101) accompanying the injection molding of the bonded magnet, suppression of increase in magnetic flux leakage, and suppression of increase in the number of filling gates.

  According to the second invention, since d1 is twice or more than d2, the demagnetization resistance is improved.

  According to the third aspect of the invention, the magnetic pole arrangement can be balanced in the entire rotor core (101).

  According to the fourth invention, the bonded magnet can be uniformly filled in the magnet slot (S100).

It is a typical longitudinal cross-sectional view for demonstrating the structural example of the compressor provided with the rotary electric machine. It is a typical cross-sectional view for demonstrating the structural example of a rotary electric machine. It is a typical cross-sectional view for demonstrating the structural example of a rotor. It is a typical cross-sectional view for demonstrating the structure of the rotor of a comparative example. It is a typical longitudinal cross-sectional view for demonstrating the structural example of a shaping die. It is a typical top view for demonstrating the lower mold | type of a shaping die. FIG. 10 is a schematic cross-sectional view for explaining a first variation of the rotor. It is a typical cross-sectional view for explaining a modification 2 of the rotor. FIG. 10 is a schematic cross-sectional view for explaining a third modification of the rotor.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The following description of the preferred embodiments is merely exemplary in nature and is not intended to limit the invention, its application, or its use. In the following drawings, components having substantially the same function are denoted by the same reference numerals for the sake of brevity.

<Embodiment>
(Compressor)
FIG. 1 shows a configuration example of a compressor (1) including a rotating electric machine (10) according to an embodiment of the present invention. The compressor (1) is used for an air conditioner (not shown), for example, and is installed in an outdoor unit (not shown) of the air conditioner. The compressor (1) includes a drive shaft (20), a compression mechanism (30), and a casing (40) in addition to the rotating electric machine (10). The rotating electrical machine (10) includes a rotor (11) and a stator (12) through which the rotor (11) is inserted. In this example, the rotating electric machine (10) constitutes an electric motor (more specifically, an embedded magnet type motor). The rotating electrical machine (10) is accommodated in the casing (40) and used to drive the compression mechanism (30) via the drive shaft (20). The compression mechanism (30) may be a scroll-type compression mechanism or a rotary-type compression mechanism, or may be another compression mechanism.

(Rotating electrical machine)
FIG. 2 shows a cross section of the rotating electrical machine (10). In the following description, “axial direction” is the direction of the axis (O) of the drive shaft (20), and “radial direction” is the direction orthogonal to the axial direction of the drive shaft (20). Yes, “circumferential direction” means the direction around the axis (O), and “outer side” means the side farther from the axis (O). "Is the side closer to the axis (O). The “longitudinal section” is a section along the axial direction, and the “cross section” is a section orthogonal to the axial direction. The rotating electric machine (10) includes a rotor (11) and a stator (12).

[Stator]
The stator (12) includes a cylindrical stator core (201) and a coil (202).

<Stator core>
The stator core (201) is a laminated core formed by punching an electromagnetic steel plate by press working to produce a laminated plate, and laminating a plurality of laminated plates in the axial direction. The stator core (201) includes a back yoke part (211), a plurality (six in this example) of tooth parts (212, 212,...), And a plurality (six in this example) of brim parts (213, 213,...). And. The back yoke portion (211) is formed on the outer peripheral portion of the stator core (201) and is formed in an annular shape. The outer periphery of the back yoke portion (211) is fixed to the inner surface of the casing (40). The teeth part (212) is formed in a rectangular parallelepiped shape extending in the radial direction from the inner peripheral surface of the back yoke part (211). Between the teeth portions (212, 212,...), Coil slots (214, 214,...) For accommodating the coils (202) are formed. The brim portion (213) is continuously formed on the inner peripheral side of the teeth portion (212). The brim portion (213) is configured to have a larger width (length in the circumferential direction) than the tooth portion (212), and the inner circumferential surface is formed into a cylindrical surface. The cylindrical surface of the brim portion (213) faces the outer peripheral surface (cylindrical surface) of the rotor (11) with a predetermined distance (air gap (G)).

<coil>
The coil (202) is wound around the tooth portion (212) by a so-called concentrated winding method. That is, the coil (202) is wound for each tooth portion (212), and the wound coil (202) is accommodated in the coil slot (214). Thereby, an electromagnet is formed in each of the tooth portions (212, 212,...). The coil winding method is not limited to the concentrated winding method, and may be a distributed winding method.

[Rotor]
Next, the rotor (11) will be described with reference to FIG. The rotor (11) has a rotor core (101) formed in a columnar shape and a plurality of (in this example, four) magnets (100, 100,...).

<Rotor core>
The rotor core (101) is formed by punching an electromagnetic steel plate by press working to produce a laminated plate, and laminating a plurality of laminated plates in the axial direction. A shaft hole (S110) is formed in the center of the rotor core (101). The drive shaft (20) is fixed to the shaft hole (S110) by shrink fitting or the like. The rotor core (101) is formed with a plurality of (four in this example) magnet slots (S100, S100,...).

-Magnet slot-
The magnet slots (S100, S100,...) Are formed in the rotor core (101) at a predetermined pitch (90 ° pitch in this example) around the axis (O). The magnet slot (S100) penetrates the rotor core (101) in the axial direction and is surrounded by the rotor core (101). In this example, the cross-sectional shape of the magnet slot (S100) is a shape in which L-shaped corner portions having the same length protrude outward.

-Magnet-
Each of the magnet slots (S100, S100,...) Is filled with a bond magnet to form a magnet (100, 100,...). The bond magnet is made of a molten resin containing magnetic powder (for example, powder of neodymium iron boron magnet or ferrite magnet). This bond magnet is injected into the magnet slot (S100, S100, ...) and solidified. Magnets (100, 100,...) Are formed by performing (that is, injection molding).

  The shape of the magnets (100, 100,...) Is the same as that of the magnet slots (S100, S100,...), And L-shaped corners having the same length of both legs protrude outward. Here, the corner portion is the center portion (21), and the two leg portions extending at right angles are the side portions (31). The arrangement shape of the magnets (100, 100,...) In the rotor core (101) is such that the center portion (21) protrudes outward in the radial direction, and both side portions (31, 31) are the center portion (21). Of the rotor core (101) passing through the center of the center portion (21) and extending straightly in a symmetrical shape with the diameter of the rotor core (101) passing through the center of the center portion (21). Both side portions (31, 31) have substantially the same length and substantially the same width.

  The width d1 along the circumferential direction of the center portion (21) is larger than the width d2 along the radial direction of the side portion (31) and is at least twice as large as d2.

-Boundary part-
The boundary portion (111) exists between the adjacent side portions (31, 31) of the two adjacent magnets (100, 100) and is a part of the rotor core (101). The boundary portion (111) is a portion of the rotor core (101) closer to the axial center (0) than the magnet slot (S100, S100,...) And radially outward from the magnet slot (S100, S100,...). The part is connected. The width of the boundary portion (111) (the distance between the two side portions (31, 31)) is smaller than d2.

[Molding mold]
Next, with reference to FIG. 5 and FIG. 6, the molding die (50) used in the injection molding of the bond magnet will be described. The molding die (50) is composed of an upper die (51) and a lower die (52). 5 corresponds to a cross section taken along line VV in FIG.

<Upper mold>
As shown in FIG. 5, the upper mold (51) has an inlet (501), a spool runner (502), and a plurality of gates (503, 503,...). Molten resin is poured into the inlet (501). The spool runner (502) supplies the molten resin injected into the injection port (501) to the gate (503, 503,...). The gates (503, 503,...) Inject the molten resin supplied from the spool runner (502). Further, the gates (503, 503,...) Are respectively located immediately above the portions corresponding to the center portions (21, 21,...) Of the magnet slots (S100, S100,...) Of the rotor core (101). In this example, four gates (503, 503,...) Respectively corresponding to the four magnet slots (S100, S100,...) Are provided.

<Lower mold>
The lower mold (52) is made of a nonmagnetic member. Moreover, the lower mold | type (52) has the recessed part formed in circular shape. As shown in FIG. 6, a plurality of (four in this example) permanent magnets (504, 504,...) And an arc shape are formed on the inner periphery of the recess of the lower mold (52). A plurality (four in this example) of pole pieces (505, 505,...) Are provided. Further, a plurality (four in this example) of contact members (506, 506,...) Formed in an arc shape are provided on the inner periphery of the permanent magnets (504, 504,...). And the rotor core housing part for housing the rotor core (101) by the bottom surface of the recess of the lower mold (52), the inner circumferential surface of the pole piece (505, 505, ...) and the inner circumferential surface of the contact member (506, 506, ...) (500) is configured.

"permanent magnet"
The permanent magnet (504) is magnetized in the circumferential direction so that one end in the circumferential direction of the permanent magnet (504) is an N pole and the other end in the circumferential direction is an S pole. The permanent magnets (504, 504,...) Are fixed to the inner peripheral surface of the concave portion of the lower mold (52) at a predetermined pitch (90 ° pitch in this example) so that the N poles and the S poles face each other. Has been.

《Pole Peace》
The pole piece (505) is made of a magnetic material (for example, iron). Further, the pole pieces (505, 505,...) Are fixed to the inner peripheral surface of the concave portion of the lower mold (52) so as to be disposed between the permanent magnets (504, 504,...). The rotor core (101) is configured so that the inner peripheral surface of the pole piece (505, 505,...) Faces the outer peripheral surface of the rotor core (101) accommodated in the rotor core accommodating portion (500) with a predetermined gap (air gap) therebetween. It is formed in a cylindrical surface shape having a radius of curvature larger than the radius of.

《Contact member》
The contact member (506) is made of a nonmagnetic material (for example, stainless steel). Further, the contact members (506, 506,...) Are respectively fixed to the inner peripheral surfaces of the permanent magnets (504, 504,...).

[Rotor manufacturing process]
Next, the manufacturing process of the rotor (11) using the molding die (50) will be described.

<Set process>
First, the inner peripheral surface of the pole piece (505, 505,...) Is opposed to the outer peripheral surface of the rotor core (101) (more specifically, the magnetic pole portion of the rotor (11)) with a predetermined distance therebetween, and contact is made. The lower core (52) accommodates the rotor core so that the inner peripheral surface of the member (506, 506,...) Is closest to the portion corresponding to the center (21) of the magnet slot (S100, S100,...) Of the rotor core (101). The rotor core (101) is accommodated in the part (500). Note that one opening end portion in the axial direction of the rotor core (101) is closed by the bottom surface of the rotor core housing portion (500). Next, the gates (503, 503,...) Are respectively opposed to the other opening end in the axial direction of the portion corresponding to the center portion (21) of the magnet slot (S100, S100,...) Of the rotor core (101). The upper mold (51) and the lower mold (52) are overlapped.

<Injection process>
Next, molten resin to be a bonded magnet is injected into the injection port (501) of the upper mold (51) by an injection unit (not shown). The molten resin injected into the inlet (501) is injected from the gate (503, 503,...) Through the spool runner (502) to the magnet slots (S100, S100,...) Of the rotor core (101).

  When filling of the molten resin into the magnet slots (S100, S100,...) Of the rotor core (101) is completed, the molten resin is solidified. In this way, magnets (100, 100,...) Are formed. Further, magnetic field orientation and magnetization of the magnets (100, 100,...) Are performed by magnetic fluxes that pass from the permanent magnets (504, 504,...) Through the pole pieces (505, 505,...) To the bond magnets of the rotor core (101). At this time, different poles are formed on the side surfaces (31, 31) on both sides of the center portion (21) on the radially outer surface of each magnet (100). That is, when the outer surface of one side part (31) of one magnet (100) becomes an N pole, the outer surface of the other side part (31) becomes an S pole.

<Removal process>
Next, the upper die (51) and the lower die (52) are separated and bonded from the rotor core housing (500) of the lower die (52) to the rotor (11) (that is, the magnet slots (S100, S100,...)). The rotor core (101) filled with the magnet is removed. In this way, the rotor (11) is manufactured.

[Pressure applied to the rotor core during injection molding]
Next, the pressure applied to the rotor core (101) during the injection molding of the bonded magnet will be described by comparing this embodiment (FIG. 3) and the comparative example (FIG. 4).

  In the rotor (11a) of the comparative example, four magnets (100a, 100a,...) Are shifted by 90 degrees in the circumferential direction, and each magnet (100a) forms one pole. That is, the radially outer surface of each magnet (100a) is a specific pole, and the radially outer surface of the adjacent magnet (100a) is the opposite pole. Such a magnet (100a, 100a,...) Has a central portion extending substantially in the circumferential direction, and both end portions are bent radially outward from the central portion. When this rotor (11a) is manufactured by injection molding, both ends will apply force to the rotor core (101a) in the direction of arrow B due to the pressure of the bond magnet filled in the magnet slot (S100a). The resultant force in the direction of arrow B applied to the rotor core (101a) from the two ends of one magnet slot (S100a) causes the rotor core (101a) portion radially outward of the magnet slot (S100a) to expand radially outward. It becomes power. Further, the central portion of the magnet slot (S100a) also applies a radially outward pressure to the rotor core (101a). Therefore, the rotor (11a) of the comparative example tends to bulge outward during injection molding.

  On the other hand, in this embodiment, the force in the direction of arrow A is applied to the rotor core (101) in the center portion (21) at the time of injection molding, but the boundary portion (111) exists. Swelling of the rotor core (101) in the radial direction due to force is suppressed.

〔effect〕
As described above, in the injection molding of the bonded magnet, the radial direction of the rotor core (101) associated with the injection molding of the bonded magnet due to the presence of the boundary portion (111) in each of the magnet slots (S100, S100,...) Swelling deformation to the outside can be suppressed, and accuracy deterioration of the air gap (G) between the rotor (11) and the stator (12) can be suppressed.

  Further, in the comparative example of FIG. 4, assuming that a boundary portion is formed at the center of the magnet (100a, 100a,...) Aiming at the same bulging suppression effect as in the present embodiment, magnetic flux leakage at this boundary portion. Will occur. Magnetic flux leakage occurs similarly at the boundary portion (111) of this embodiment, but in the comparative example, magnetic flux leakage also occurs at the magnetic pole separation portion (121) that is the boundary portion between two adjacent magnets (100a, 100a). Since this magnetic pole separation part (121) is longer than the boundary part, the magnetic flux leakage degree is large. Therefore, in this embodiment, magnetic flux leakage is reduced as compared with the comparative example.

  Assuming that the boundary portion is formed in the comparative example of FIG. 4 as described above, eight magnet slots (S100a, S100a,...) Are required, but in this embodiment, the magnet slots (S100, S100) are required. ,...) Are four in half, and only four gates are required at the time of injection molding, thereby suppressing an increase in the cost of injection molding.

  Furthermore, in this embodiment, since the width d1 along the circumferential direction of the center portion (21) of each magnet (100) is larger than the width d2 along the radial direction of the side portion (31), the demagnetization resistance is improved. Can be made. In particular, it is preferable that d1 is twice or more than d2, since the effect of improving the demagnetization resistance becomes remarkable.

  Each of the four magnets (100, 100,...) Has a line-symmetric shape with the diameter passing through the center portion (21) as the axis of symmetry, all four have the same shape, and the axis (0) is the center. Since they are arranged in a symmetrical shape rotated by 90 degrees, the magnetic pole arrangement is balanced throughout the rotor core (101).

(Modification 1 of rotor core)
As shown in FIG. 7, the cross-sectional shape of the magnet slot (S103, S103,...) And the magnet (103, 103,...) May be a shape in which the ends of two arcs are joined together. In this case, the portion where the ends of the two arcs are joined is the center portion (23), and protrudes outward in the radial direction. The arc part is the two side parts (33, 33), and the diameter of the rotor core (102) passing through the center of the center part (23) from the axis (0) side of the center part (23) is the axis of symmetry. Each extends in a symmetrical shape. The bulge direction of the arc of the side portions (33, 33) is opposite to the bulge direction of the outer periphery of the rotor core (102). The side portions (33, 33) of the adjacent magnets (103, 103) are separated by a boundary portion (113) by a distance equal to or less than the width along the radial direction of the side portion (33). The width along the circumferential direction of the center portion (23) is larger than the width along the radial direction of the side portion (33) and is twice or more.

  The rotating electric machine using the rotor core (102) of the first modification also has the same effect as the rotating electric machine shown in FIG.

(Modification 2 of rotor core)
As shown in FIG. 8, the cross-sectional shapes of the magnet slots (S105, S105,...) And the magnets (105, 105,...) Set the 90 ° angle between the side portions (31, 31) shown in FIG. It may be a shape. In this case, the shape and size of the center portion (25) are the same as those of the rotor core (101) in FIG. The side portions (35, 35) of the adjacent magnets (105, 105) are separated by a boundary portion (115) by a distance equal to or less than the width along the radial direction of the side portion (35). The width along the circumferential direction of the center portion (25) is larger than the width along the radial direction of the side portion (35) and is twice or more.

  The rotating electric machine using the rotor core (104) of the modified example 2 has the same effect as the rotating electric machine shown in FIG.

(Modification 3 of rotor core)
As shown in FIG. 9, the cross-sectional shapes of the magnet slots (S107, S107,...) And the magnets (107, 107,...) Are bent outward in the radial direction while the side portion (31) shown in FIG. May be. In this case, the shape and size of the center portion (27) are the same as those of the rotor core (101) in FIG. The side portions (37, 37) of the adjacent magnets (107, 107) are separated by a boundary portion (117) by a distance equal to or less than the width along the radial direction of the side portion (37). The width along the circumferential direction of the center portion (27) is larger than the width along the radial direction of the side portion (37) and is twice or more.

  The rotating electric machine using the rotor core (106) of the third modification also has the same effect as the rotating electric machine shown in FIG.

<Other embodiments>
The above-described embodiments and modifications are exemplifications of the present invention, and the present invention is not limited to these examples. These examples may be combined with, or partially replaced with, well-known techniques, conventional techniques, and known techniques. Good. Also, modified inventions easily conceived by those skilled in the art are included in the present invention.

  As described above, the rotating electric machine described above is useful as an electric motor used for a compressor.

11 rotor 12 stator 13 rotor 15 rotor 17 rotor 21 center part 23 center part 25 center part 27 center part 31 side part 33 side part 35 side part 37 side part 100 magnet 101 rotor core 102 rotor core 103 magnet 104 rotor core 105 magnet 106 rotor core 107 magnet 111 boundary portion 113 boundary portion 115 boundary portion 117 boundary portion S100 magnet slot S103 magnet slot S105 magnet slot S107 magnet slot

Claims (4)

A rotor (11) having a plurality of magnets (100) and a rotor core (101), and a stator (12) through which the rotor (11) is inserted;
The magnet (100) is a bonded magnet filled in a magnet slot (S100), which is a hole penetrating the rotor core (101) in the axial direction, and protrudes outward in the radial direction of the rotor (11). A center portion (21), and two side portions (31, 31) extending symmetrically apart from each other in the radial direction of the center portion (21),
In the cross section, the periphery of the magnet (100) is surrounded by the rotor core (101),
The width d1 along the circumferential direction of the center portion (21) is larger than the width d2 along the radial direction of the side portion (31),
The side portions (31) of the adjacent magnets (100) are separated by a boundary portion (111) that is a part of the rotor core (101) at a distance of d2 or less. Electric machine.   The dynamoelectric machine according to claim 1, wherein the d1 is at least twice the d2.   The rotating electrical machine according to claim 1 or 2, wherein the boundary portion (111) is located at a substantially equal distance from the center portions (21) of the adjacent magnets (100).   The rotating electrical machine according to any one of claims 1 to 3, wherein the bond magnet is filled from a filling gate located on the center portion (21).

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