JP2014057443A - Magnet embedded rotor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magnet embedded rotor capable of suppressing demagnetization and deterioration of magnet force at the slot end part (corner) by adequately filling a bond magnet in a rotor core slot.SOLUTION: A slot (33) to be filled with a bond magnet is formed in a rotor core (30). A lower end plate (40) for covering a lower end part of the rotor core (30) is disposed at the lower end part of the rotor core (30) in the rotation axis direction. In the lower end plate (40), a recess (45) for opening into the slot (33) is formed at a place corresponding at least partially to the slot (33). Consequently, a part of the bond magnet is also filled in the recess (45) of the lower end plate (40), when filling in (ejecting) a bond magnet.

Description

  The present invention relates to a magnet-embedded rotor, and in particular, relates to one in which a bonded magnet is injected and filled into a slot of a rotor core by injection molding.

  Conventionally, in an interior permanent magnet motor, a plurality of slots are provided in the rotor core, and magnets are embedded in these slots to embed magnets in these slots, and magnets are attached to the rotor surface to attach the magnet to the surface of the rotor. Like a child, it prevents scattering of the magnet at high rotation.

  For manufacturing such a magnet-embedded rotor, conventionally, there is a technique of filling each slot of the rotor core with a bond magnet (thermoplastic resin mixed magnet) by injection molding. In this technique, for example, in Patent Document 1, after a rotor core is mounted in a lower rotor core housing portion of a molding die, a bond magnet is injected (injected) from an upper mold inlet (gate), and each slot of the rotor core is injected. A structure in which a bonded magnet is filled is adopted.

JP 2003-47212 A

  However, in the above-described conventional technique, when the rotor core is mounted in the lower rotor core housing portion of the molding die, the lower end surface of the rotor core only comes into surface contact with the upper end surface of the lower rotor core housing portion. For this reason, as shown in FIG. 8, there is a possibility of insufficient filling A of the bond magnet (98) at the lower end of the slot (97) surrounded by the rotor core (95) and the lower mold (96). In particular, since the vicinity of the outer peripheral end of the lower end portion of the slot (97) is formed at the corner portion, there is a high possibility that the bonding magnet (98) will be insufficiently filled near the outer peripheral end of the lower end portion.

  On the other hand, the corner near the outer peripheral edge of the lower end of the slot (97) is easy to demagnetize, so it is necessary to sufficiently fill the bond magnet to increase permeance, but the lower end of the slot (97) Insufficient filling of the bond magnet (98) in the vicinity of the outer peripheral edge of the part causes a decrease in magnetic force, which is not preferable.

  In view of this, the object of the present invention is to sufficiently stabilize the torque characteristics and the like by sufficiently filling the slot with a bonded magnet to suppress demagnetization at the slot end of the bonded magnet and to suppress a decrease in magnetic force. An object is to provide a magnet embedded rotor that can be secured.

  A magnet-embedded rotor according to a first aspect of the present application is a magnet-embedded rotor in which a bond magnet is injected into a slot (33) formed in a rotor core (30) of a rotary electric machine, the rotor core End plates (40), (71), (81), (91) for closing the end portions are disposed on at least one of both end portions in the rotation axis direction of (30), and the end plates (40), In (71), (81), and (91), recesses (45), (74), and (84) that open to the slot (33) are formed at locations corresponding to at least part of the slot (33). In addition, a part of the bonded magnet is injected into the recesses (45), (74), (84) of the end plates (40), (71), (81), (91). Features.

  In the first invention, the bond magnet injected into the slot of the rotor core at the time of injection molding of the bond magnet is further injected into the recess of the end plate from the end surface in the rotation axis direction of the slot. Therefore, even if the bond magnet is insufficiently filled in the recess of the end plate, the bond magnet is sufficiently filled in the slot, particularly the end of the slot where the demagnetization is likely to occur. Insufficient filling of the bonded magnet does not occur at the end (corner). Therefore, demagnetization and magnetic force decrease at the end of the slot can be effectively suppressed, and stability such as torque characteristics of the magnet-embedded electric motor can be ensured as expected.

  According to a second aspect of the present invention, in the magnet-embedded rotor according to the first aspect, the recess (45) of the end plate (40) opens in the same shape as the end face shape of the slot (33). It is characterized by.

  In the second invention, since the opening shape of the concave portion of the end plate is the same shape as the end face shape of the slot, at the time of injection (injection) of the bonded magnet, the central portion or corner portion of the end portion of the slot in the rotation axis direction is used. The bond magnet is reliably injected, and insufficient filling of the bond magnet at the end portion (corner portion) where the slot is easily demagnetized is effectively suppressed.

  Further, according to a third aspect of the present invention, in the magnet-embedded rotor according to the first aspect, the recess (74) of the end plate (71) opens only in the central portion (33b) of the slot (33). It is characterized by that.

  In addition, according to a fourth aspect of the present invention, in the magnet-embedded rotor according to the first aspect, the recess (84) of the end plate opens only at both ends (33a) of the slot (33). Features.

  In the third and fourth inventions, since the volume of the concave portion of the end plate is small, there is insufficient filling of the bond magnet at the end portion (corner) where the slot is likely to be demagnetized while limiting the required amount of the bond magnet. Effectively suppressed.

  According to a fifth aspect of the present invention, in the magnet-embedded rotor according to any one of the first, third, and fourth aspects, the end plates (71) and (81) are two sheets having through holes. Of the two end plates (70), (80), one of the two end plates (70), (80) being shifted by a predetermined angle with respect to the other so that the recesses (74), (84) It is formed.

  In the fifth invention, since the recess is formed by using two end plates having the same shape and having through holes, the configuration of the end plate can be simplified as compared with the case of creating an end plate having a recess. This end plate can be made at low cost.

  As described above, according to the first invention of the present application, during the injection molding of the bond magnet, the bond magnet is also injected into the recess of the end plate from the slot end face. Even if insufficient filling occurs, the slot can be sufficiently filled with bonded magnets, so that demagnetization and magnetic force drop at the end (corner) where the slot is likely to be demagnetized can be effectively suppressed and the magnet embedded. Stability such as torque characteristics of embedded motors can be ensured as expected.

  According to the second invention, since the shape of the recess of the end plate is the same as the shape of the end surface of the slot, it is possible to effectively suppress insufficient filling of the bond magnet at the end of the slot where the demagnetization is easy. Is possible.

  Further, according to the third and fourth inventions, since the volume of the concave portion formed in the end plate is limited to a small amount, the bond at the end portion where the demagnetization of the slot is easy while limiting the required amount of the bond magnet to a small amount. Insufficient magnet filling can be effectively suppressed.

  In addition, in the fifth invention, since the concave portion is formed by using two end plates having the same shape and having through holes, the end plate of the end plate is compared with the case where one end plate having the concave portion is formed. The configuration can be simplified and this end plate can be produced at low cost.

FIG. 1 is a cross-sectional view showing a configuration of an embedded magnet motor having an embedded magnet rotor according to a first embodiment of the present invention. FIG. 2 is an exploded perspective view of the magnet-embedded rotor. FIG. 3 is a cross-sectional view for explaining a state in which the bonded magnet is filled into the magnet slot and the concave portion of the lower end plate of the embedded magnet rotor. FIG. 4 is an exploded perspective view of the magnet-embedded rotor according to the second embodiment. FIG. 5 is a cross-sectional view for explaining a state in which the bonded magnet is filled into the magnet slot and the concave portion of the lower end plate of the embedded magnet rotor. FIG. 6 is an exploded perspective view of the magnet-embedded rotor according to the third embodiment. FIG. 7 is an exploded perspective view of the magnet-embedded rotor according to the fourth embodiment. FIG. 8 is a cross-sectional view for explaining a state of filling a bonded magnet into a slot of a conventional embedded magnet rotor.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The following embodiments are essentially preferable examples, and are not intended to limit the scope of the present invention, its application, or its use.

(First embodiment)
FIG. 1 shows a cross-sectional configuration of an embedded magnet motor having an embedded magnet rotor according to a first embodiment of the present invention.

  In the figure, an embedded magnet motor (1) includes a stator (2), an embedded magnet rotor (3), and a rotating shaft (4).

  The stator (2) includes a cylindrical stator core (10) and a coil (11). The stator core (10) is formed by punching an electromagnetic steel plate by press working to create a laminated plate, and the plurality of laminated plates are arranged in the axial direction of the rotating shaft (4) (the direction of the axis O of the rotating shaft (4), hereinafter A plurality of (13 in the figure) teeth portions (13) having a rectangular parallelepiped shape extending toward the rotation axis center 0, and a laminated core laminated in an axial direction); And a brim portion (14) formed on the inner peripheral side of each tooth portion (13). And the said coil (11) is wound by the concentrated winding system on the outer periphery of each said teeth part (13). The flange portion (14) has an inner peripheral surface formed in a cylindrical surface, and this cylindrical surface is opposed to the outer peripheral surface of the magnet-embedded rotor (3) with a predetermined air gap (G).

  The magnet-embedded rotor (3) includes a cylindrical rotor core (30) in which the rotation shaft (4) is disposed at the center, and four arc-shaped rotors embedded in the rotor core (30). A quadrupole structure including a magnet (31). A specific configuration of the magnet-embedded rotor (3) is shown in FIG.

  FIG. 2 is an exploded perspective view of the magnet-embedded rotor (3). In the magnet-embedded rotor (3) in the figure, the rotor core (30) is formed by superposing a plurality of electromagnetic steel plates (30a) made of disk-shaped thin steel plates. Each of the electromagnetic steel plates (30a) has a shaft hole (32) of the rotating shaft (4) formed at the center, and four arc-shaped magnet slots (33) at the edge portion of the electromagnetic steel plates (30a). ) Are formed so as to penetrate through the top and bottom of the substrate. Each magnet slot (33) has a shape in which both arc-shaped end portions (33a) are positioned on the outer peripheral side of the rotor core (30) and an arc-shaped center portion (33b) is close to the rotating shaft (4). Each magnet slot (33) is injected (injected) with a bonded magnet (thermoplastic resin mixed magnet) into each magnet slot (33), as will be described later. A similar arc-shaped magnet (31) is embedded.

  A lower end plate (40) that covers the lower end surface of the rotor core (30) is located below the rotor core (30). The lower end plate (40) is formed with a shaft hole (42) of the rotating shaft (4) at the center and four edges at the edge, like the electromagnetic steel plates (30a) of the rotor core (30). An arcuate recess (45) is formed. Each concave portion (45) is close to both end portions (45a) located on the outer peripheral side of the lower end plate (40) and the shaft hole (42), similarly to the magnet slot (33) of the electromagnetic steel plate (30a). And the positions of both end portions (45a) and the central portion (45b) are the end portions (33a) and the central portion (33a) of the magnet slot (33) of the electromagnetic steel sheet (30a). Opposite to 33b), an opening is formed in the same shape as the lower end opening shape of the magnet slot (33) of the rotor core ((30)).

  On the other hand, an upper end plate (50) covering the upper end surface of the rotor core (30) is positioned above the rotor core (30) in the axial direction. As with the lower end plate (40), the upper end plate (50) is also formed with a shaft hole (52) of the rotating shaft (4) in the center, but injection of the bond magnet at the time of injection molding of the bond magnet As the holes, four arc-shaped through holes (53) having the same shape as the upper end opening shape of the magnet slot (33) of the rotor core (30) are formed at the edge.

  The lower end plate (40) and the upper end plate (50) are each formed thicker than the thickness of each electromagnetic steel plate (30a) of the rotor core (30), and are preferably integrally formed by die casting with a nonmagnetic material such as aluminum. Is done.

  The rotor core (30), the lower end plate (40), and the upper end plate (50) are pin insertion holes (60) into which caulking pins (not shown) for caulking these three members from the axial direction are inserted. Are formed on the edge at equal intervals.

  In the present embodiment, the four arc-shaped magnets (31) are formed by injection molding of a bonded magnet. At the time of this injection molding, the upper end plate (50), the rotor core (30), and the lower end plate (40) are positioned in this order from the top, and after the caulking pins are inserted into the respective pin insertion holes (60), the whole is caulked, A bonded magnet is injected (injected) from the gate of the molding die into the magnet slot (33) of the rotor core (30) through the through hole (53) of the upper end plate (50), and the arc-shaped magnet (31) is injection molded. Is done.

  Here, the injected bond magnet is injected not only into the space in the magnet slot (33) of the rotor core (30) but also into the recess (45) of the lower end plate (40). Since the shape of the upper surface opening of the recess (45) of the lower end plate (40) is the same as the shape of the lower end surface of the magnet slot (33) of the rotor core (30), it was injected into each magnet slot (33). Bond magnets are injected from the entire end surface in the rotation axis direction of the magnet slots (33) into the recesses (45) of the end plate (40) following the end surfaces. Since the volume of the injected bonded magnet exceeds the total volume of the magnet slot (33) of the rotor core (30), as shown in FIG. 3, both ends of the recess (45) of the lower end plate (40) are used. Even if the bond magnet is insufficiently filled in the part (45a), the left and right ends (33a) of the magnet slot (33) of the rotor core (30) will not be insufficiently filled with the bond magnet, Filled. In particular, since the shape of each concave portion (45) of the lower end plate (40) is an arc shape, filling of the bonded magnet is stable without being affected by changes in the ambient temperature during injection molding and the temperature of the bonded magnet.

  Therefore, the injection-molded arc-shaped magnet (31) is formed into a shape as designed, and is sufficiently filled with bond magnets at both ends (33a) of the magnet slot (33) that is easy to demagnetize. Demagnetization is suppressed, magnetic force drop is suppressed, and furthermore, the torque characteristics of the magnet-embedded motor (1) are stabilized as desired.

(Second Embodiment)
FIG. 4 is an exploded perspective view of the magnet-embedded rotor (3) according to the second embodiment of the present invention.

  The magnet-embedded rotor (3) shown in the figure is different from the lower end plate (40) in FIG. 2 in the configuration of the lower end plate. In the lower end plate of the figure, the lower end plate (71) is constituted by two end plates (70). Each end plate (70) has a shaft hole (72) of the rotating shaft (4) at the center and four through holes (73). Each of these through holes (73) is formed in a quadrangular shape that opens to face the central portion (33b) of the magnet slot (33) of the rotor core (30). Of these two end plates (70), the lower end plate (70) is rotated with respect to the upper end plate (70) by ½ of the magnetic pole pitch (45 ° in this embodiment). The two end plates (70) are overlapped, and the through hole (73) of the upper end plate (70) is replaced with the flat plate portion of the lower end plate (70) (the portion other than the through hole (73)). Four recesses (74) are formed in the lower end plate (71).

  Since the two end plates (70) are configured such that one of them is rotated by 45 ° to form a recess (74) in the lower end plate (71), a pin is inserted into the edge of each end plate (70). A total of eight holes (60) are formed 45 ° apart. Since other configurations are the same as those of the first embodiment, the same portions are denoted by the same reference numerals and the description thereof is omitted.

  In the present embodiment, at the time of injection molding of the bonded magnet, the bonded magnet is injected (injected) using both ends of each through hole (53) of the upper end plate (50) as gates (g). The injected bonded magnet fills the space in the magnet slot (33) of the rotor core (30) from the both end portions (33a) toward the central portion (33b), and from the central portion (33b), It also flows out into the recess (74) of the lower end plate (71) that opens only in the central portion (33b).

  Therefore, similarly to the first embodiment, the volume of the bonded magnet to be injected exceeds the total volume of the magnet slot (33) of the rotor core (30), and the filling of the magnet slot (33) is insufficient. Since the left and right end portions (33a) are easily filled first, as shown in FIG. 5, it is assumed that the left and right end portions (45a) of the concave portion (74) of the lower end plate (71) are insufficiently filled with bond magnets. However, the left and right ends (33a) of the magnet slot (33) of the rotor core (30) are not filled with the bond magnet, and the bond magnet is sufficiently filled. Accordingly, as in the first embodiment, the injection-molded arc-shaped magnet (31) is formed into a shape as designed, and both left and right ends (33a) of the magnet slot (33) that is easy to demagnetize. The sufficient demagnetization of the bonded magnets suppresses the demagnetization, suppresses the decrease in magnetic force, and further stabilizes the torque characteristics of the magnet-embedded motor (1) as desired. Further, since the lower end plate (71) has the recess (74) in the central portion (33b) serving as the weld line, the magnet slot (33) in the rotor core (30) is not insufficiently filled. Accordingly, insufficient filling does not occur in the magnet central portion (portion located most inside the rotor) where the magnetization rate (orientation rate) generally decreases, and demagnetization can be avoided.

  Moreover, in the present embodiment, the recess (74) of the lower end plate (71) opens only in the central portion (33b) of the magnet slot (33) of the rotor core (30), so that the magnet as in the first embodiment. Compared to the case where the entire bottom surface of the slot (33) is opened, the shortage of bonding magnets in the left and right end portions (33a) where the magnet slot (33) is easily demagnetized is reduced with a small bonded magnet capacity. It is possible.

(Third embodiment)
FIG. 6 is an exploded perspective view of a magnet-embedded rotor (3) according to the third embodiment of the present invention.

The magnet-embedded rotor (3) shown in the figure is different from the lower end plate (70) in FIG. 4 in the configuration of the lower end plate. In the lower end plate of the figure, the point that the two end plates (80) constitute the lower end plate (81) and the point that the through holes (83) are formed in each end plate (80) are the above-mentioned second plate. In the same manner as in the embodiment, each of the through holes (83) is formed in a total of eight rectangular shapes that open at the edges facing both ends (33a) of the magnet slots (33) of the rotor core (30). The As in the second embodiment, the lower end plate (80) of the two end plates (80) is rotated by half the magnetic pole pitch with respect to the upper end plate (80) ( In this embodiment, the two end plates (80) are overlapped with each other rotated 90 degrees, and the through hole (83) of the upper end plate (80) is formed into a flat plate of the lower end plate (80). Eight recessed portions (84) are formed in the lower end plate (81) by closing the portion (a portion other than the through hole (83)). Other configurations are the same as those of the second embodiment.

  In the present embodiment, at the time of injection molding of the bonded magnet, the bonded magnet is injected (injected) using the central portion of each through hole (53) of the upper end plate (50) as the gate (g). The injected bonded magnet fills the space in the magnet slot (33) of the rotor core (30) from the central portion (33b) toward both ends (33a), and from both ends (33a), It also flows out into the recess (84) of the lower end plate (81) that opens only at both ends (33a).

  Therefore, as in the second embodiment, the volume of the bonded magnet to be injected exceeds the total volume of the magnet slot (33) of the rotor core (30), and the left and right ends (33a) of the magnet slot (33) ) Is further injected into the concave portion (84) of the lower end plate (81) that opens to both end portions (33a). Even if the filling is insufficient, the right and left ends (33a) of the magnet slot (33) of the rotor core (30) are not filled with the bonded magnet, and the bonded magnet is sufficiently filled. Accordingly, as in the second embodiment, the arc-shaped magnet (31) formed by injection molding is formed into a shape as designed, and the left and right end portions (33a) of the magnet slot (33) that is easy to demagnetize. The sufficient demagnetization of the bonded magnets suppresses the demagnetization, suppresses the decrease in magnetic force, and further stabilizes the torque characteristics of the magnet-embedded motor (1) as desired.

  In addition, in the present embodiment, the concave portion (84) of the lower end plate (81) opens only to the left and right end portions (33a) of the magnet slot (33) of the rotor core (30), as in the first embodiment. Compared to the case where the entire bottom surface of the magnet slot (33) is opened, the shortage of the bonded magnet in the left and right end portions (33a) where the magnet slot (33) is easily demagnetized with a small bonded magnet capacity is eliminated. Is possible.

(Fourth embodiment)
FIG. 7 is an exploded perspective view of a magnet-embedded rotor (3) according to the fourth embodiment of the present invention.

  In the magnet-embedded rotor (3) shown in the figure, a lower end plate (91) is constituted by two end plates (80) and (90), and the upper end plate (80) is the third plate. This is the same configuration as the upper end plate (80) of the embodiment. On the other hand, the lower end plate (90) is composed of a balance weight. This balance weight (90) is used when the rotating shaft (4) is a rotating shaft that drives an eccentric piston, such as a compressor of an air conditioner, and the shaft of the rotating shaft (4) is at the center thereof. In addition to having a hole (92), a semicircular weight portion (93) is formed in the lower half of the figure, and a semicircular space portion (94) is formed on the upper side of the figure leaving an edge. . Then, the upper end plate (80) and the lower end plate (balance weight) (90) are overlapped, and the through-hole (83) positioned at the edge of the upper end plate (80) is balanced weight ( Four recesses (84) are formed in the lower end plate (91) by closing at the edge of 90).

  Therefore, in this embodiment as well, as in the third embodiment, the bonding magnet is insufficiently filled at the left and right ends (33a) of the magnet slot (33) of the rotor core (30) with a small bonded magnet capacity. Suppressing the magnetic demagnetization effect at the left and right ends (33a) of this magnet slot (33) and the effect of reducing the magnetic force decrease, as well as the torque characteristics of the magnet-embedded motor (1) as desired It is possible to stabilize.

  In the present embodiment, the lower end plate (90) of the two end plates (80), (90) of the lower end plate (91) is also used as the balance weight (90). It is possible to reduce the weight of the embedded rotor (3).

(Other embodiments)
The present invention may be configured as follows for each of the above embodiments.

  In the first to fourth embodiments, the four-pole structure embedded magnet rotor (3) has been described as an example. However, the present invention is a six-pole structure or a magnet-embedded structure having more than eight poles. Of course, it can be applied to the rotor.

  The magnet slots (33) of the magnet (31) and the rotor core (30) have one arc shape per magnetic pole, but a configuration in which a plurality of arc shapes are arranged concentrically may be employed. Further, the shape of the magnet slots (33) of these magnets (31) and the rotor core (30) is not limited to an arc shape, but may be a rectangular parallelepiped shape, and in short, the bottom plate (40), (71), The recesses (45), (74), and (84) of (81) and (91) may be formed so as to open in part or all of the lower surface of the magnet slot (33) of the rotor core (30).

  Furthermore, in the first to fourth embodiments, an upper end plate (50) is arranged on the upper side in the axial direction of the rotor core (30), and the upper end plate (50), the rotor core (30), the lower end plate (40), (71), (81) or (91) is fastened with a caulking pin, but the upper end plate (50) is not disposed, the rotor core (30) and the lower end plate (40), (71), (81) or ( 91) may be fastened with a caulking pin.

  As described above, according to the present invention, in an embedded magnet rotor in which a bonded magnet is injected into a slot of a rotor core, an end plate having a recess opened in at least a part of the axial end surface of the slot is provided. Therefore, it is possible to obtain an embedded magnet rotor in which a bond magnet is sufficiently filled in a slot of the rotor core, in particular, an end portion of the slot that is easily demagnetized. Useful.

DESCRIPTION OF SYMBOLS 1 Magnet embedding type motor 2 Stator 3 Magnet embedding type rotor 4 Rotating shaft 30 Rotor core 30a Laminated steel plate 31 Magnet 32 Shaft hole 33 Magnet slot 33a End portion 33b Central portion 40, 71, 81, 91 Lower end plate 42, 52 , 82, 92 Shaft holes 45, 74, 84 Recess 50 Upper end plate 53 Through hole g Gate 60 Pin insertion hole 70, 80 End plate 73, 83 Through hole 90 Balance weight 93 Weight part 94 Space part

Claims (5)

A magnet embedded rotor in which a bond magnet is injected into a slot (33) formed in a rotor core (30) of a rotating electrical machine,
End plates (40), (71), (81), (91) for closing the end portions are disposed on at least one of both end portions in the rotation axis direction of the rotor core (30),
In the end plates (40), (71), (81), (91), recesses (45), (74) that open to the slot (33) at locations corresponding to at least a part of the slot (33). ), (84) is formed,
A part of the bond magnet is injected into the recesses (45), (74), (84) of the end plates (40), (71), (81), (91). Embedded magnet rotor. In the magnet-embedded rotor according to claim 1,
The recessed part (45) of the end plate (40) opens in the same shape as the end face shape of the slot (33). In the magnet-embedded rotor according to claim 1,
The recessed part (74) of the end plate (71) opens only in the central part (33b) of the slot (33). In the magnet-embedded rotor according to claim 1,
The recessed portion (84) of the end plate (81) opens only at both end portions (33a) of the slot (33). In the embedded magnet type rotor according to any one of claims 1, 3, and 4,
The end plates (71) and (81) are composed of two end plates (70) and (80) having through holes,
One of the two end plates (70), (80) is shifted from the other by a predetermined angle and overlapped to form the recesses (74), (84). Rotor.

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