JP4313378B2 - Embedded magnet type rotating electric machine - Google Patents

Description

  The present invention relates to an interior magnet type rotating electrical machine.

  2. Description of the Related Art Conventionally, an embedded magnet type rotating electrical machine (motor) includes a rotor in which a plurality of housing holes that extend in the axial direction and extend in the radial direction are formed in a circumferential direction in a rotor core and a magnet is disposed in each housing hole. In some cases, the rotor is rotatably accommodated inside the stator.

And as such an embedded magnet type rotating electrical machine, the rotor core has some configuration such as opening the radial inner side of the accommodation hole in the rotor core and configuring the rotating shaft fitted in the rotor core with a nonmagnetic material. There is one that magnetically separates it from the rotating shaft, thereby reducing the leakage magnetic flux on the radially inner side of the magnet and increasing the effective magnetic flux (see, for example, Patent Document 1).
JP 2004-173491 A

  However, in the above-described embedded magnet type rotating electrical machine (see Patent Document 1), since the radial inner side of the accommodation hole is open, the rigidity of the rotor core is weak and the rotating shaft is made of a nonmagnetic material. There are various problems such as the need for

  Therefore, the inner side in the radial direction of the magnet is formed by forming an extending portion extending radially outward from the circumferential end of the magnet at the radially inner end of the receiving hole without opening the radial inner side of the receiving hole in the rotor core. A configuration in which the magnetic flux of the leakage magnetic flux in the case is lengthened to reduce the leakage magnetic flux is conceivable. However, in this case, the leakage magnetic flux cannot be sufficiently reduced, and there is still a problem with respect to the reduction of the leakage magnetic flux. Note that this reduces the effective magnetic flux (relative to the stator) in the rotor of the embedded magnet type rotating electrical machine, which in turn causes the motor efficiency to be lowered.

  The present invention has been made to solve the above problems, and an object of the present invention is to provide an embedded magnet type rotating electrical machine capable of reducing leakage magnetic flux and increasing effective magnetic flux.

According to the first aspect of the present invention, the embedding includes a rotor core having a plurality of receiving holes extending in the circumferential direction and penetrating in the axial direction, and having a magnet disposed in the receiving hole. A magnet-type rotating electrical machine, wherein a radially inner end portion of the housing hole extends outward from the circumferential end portion of the magnet so as to have a radial width from the circumferential end thereof, and A guide extending portion extending radially outward from the radially inner end portion is formed, and an outer extending portion extending radially outward from both ends in the circumferential direction is formed at the radially outer end portion of the receiving hole . .

According to this configuration, the radially inner end of the accommodation hole in which the magnet is disposed extends from the circumferential end to the outer side in the circumferential direction so as to have a width in the radial direction, and the magnet Since a guide extending portion extending outward in the radial direction from the radially inner end portion of the magnet is formed, the magnetic path of the leakage magnetic flux on the radially inner side of the magnet becomes longer, and the magnetic flux is at least the radially outer end of the guide extending portion. To the outside in the radial direction. Therefore, the leakage flux is reduced and the effective flux is increased.

  According to a second aspect of the present invention, in the interior magnet type rotating electric machine according to the first aspect, the radially outer inner wall of the guide extension portion is closer to the outer side in the circumferential direction than the circumferential end portion of the magnet. It has a curved surface that faces radially outward.

  According to the same configuration, the radially outer inner wall of the guide extension portion has a curved surface that goes radially outward from the circumferential end of the magnet toward the circumferential outer side, so that the magnetic flux follows the curved surface. It is smoothly guided radially outward.

According to a third aspect of the present invention, in the embedded magnet type rotating electric machine according to the second aspect, the guide extending portion has a larger radial width toward the outer side in the circumferential direction than the circumferential end portion of the magnet. It was done.
According to this configuration, in addition to the configuration described in claim 2, the guide extension portion has a radial width that increases toward the outer side in the circumferential direction from the circumferential end portion of the magnet. Without causing the projecting portion to protrude radially inward (in other words, while maintaining the radial width of the substantially annular portion radially inward of the rotor core substantially constant), the guide extending portion is widened in the radial width to leak. The magnetic path of magnetic flux can be lengthened. Therefore, while maintaining the rigidity of the rotor core, the leakage magnetic flux is further reduced and the effective magnetic flux is further increased.

  According to a fourth aspect of the present invention, in the embedded magnet type rotating electric machine according to the third aspect, the guide extending portions in the accommodation holes adjacent in the circumferential direction are adjacent to the inner walls facing in the circumferential direction. Have parallel surfaces.

  According to the same configuration, the guide extending portions in the accommodation holes adjacent in the circumferential direction have parallel surfaces between the adjacent inner walls facing each other in the circumferential direction, so that the width of the magnetic path of the leakage magnetic flux extending in the radial direction is increased. It can be made thinner (as viewed from the axial direction). Therefore, the leakage magnetic flux is further reduced and the effective magnetic flux is further increased.

According to a fifth aspect of the present invention, in the embedded magnet type rotating electric machine according to any one of the first to fourth aspects, the guide extension portion extends radially outward to a radial center position of the magnet. .
According to this configuration, since the guide extension portion extends radially outward to the radial center position of the magnet, the magnetic flux is from the radially inner side than the radial center position of the magnet and has no guide extension portion. Then, the magnetic flux going from the radially inner side to the other pole of the magnet is guided to the radially outer side from the radial center position of the magnet.

  ADVANTAGE OF THE INVENTION According to this invention, an embedded magnet type rotary electric machine which can reduce a leakage magnetic flux and can increase an effective magnetic flux can be provided.

Hereinafter, an embodiment of the present invention will be described with reference to FIG. As shown in FIG. 1, an embedded magnet type motor as an embedded magnet type rotating electrical machine includes a stator 1 and a rotor 2.
The stator 1 is formed in a substantially cylindrical shape as a whole, and has a plurality of teeth 4 formed so as to extend from the inner peripheral surface of the cylindrical portion 3 forming the outer shape toward the axial center at equal circumferential intervals. The stator core 5 is provided with a winding 6 (only part of which is shown by a two-dot chain line in FIG. 1) wound around each tooth 4 by concentrated winding via an insulator (not shown). In the present embodiment, twelve teeth 4 are formed.

The rotor 2 includes a rotating shaft 7, a rotor core 8 fixed to the rotating shaft 7, and a magnet 9 disposed in an accommodation hole 8 a formed in the rotor core 8.
More specifically, the rotor core 8 is formed by stacking core sheets in the axial direction, and is formed in a substantially cylindrical shape in which the rotating shaft 7 is press-fitted into a center hole. The rotor core 8 is formed with a plurality of (10 in the present embodiment) accommodation holes 8a extending in the axial direction and extending in the radial direction, and the magnets 9 are accommodated and held in the accommodation holes 8a. . The magnet 9 is formed in a substantially rectangular parallelepiped shape that is magnetized in the short direction (the circumferential direction in a state of being disposed in the accommodation hole 8a) when viewed from the axial direction. And the pole which opposes the circumferential direction by the magnets 9 adjacent to the circumferential direction is made the same, and one magnetic pole (S pole or N pole) is comprised by them.

  In addition, the radially inner end of each accommodation hole 8a of the rotor core 8 extends radially outward from the circumferential end of the magnet 9 (short end in the short direction when viewed from the axial direction) and radially inward of the magnet 9. A guide extending portion 8b extending outward in the radial direction from the end portion is formed. Specifically, the guide extension portion 8b is first extended to have a width in the radial direction from both ends in the radial direction of the radially inner end of the accommodation hole 8a, and further, the circumferential direction of the magnet 9 while keeping the width constant. It is set as the curved shape which goes to a radial direction outer side, so that it goes to the circumferential direction outer side from an edge part. The inner wall of the guide extension 8b of the present embodiment on the radially outer side (side closer to the outer periphery of the rotor core 8) is more radially outward from the circumferential end of the magnet 9 in the circumferential direction. A curved surface 8c is formed. Further, the guide extending portion 8 b of the present embodiment extends radially outward to the radial center position X of the magnet 9. In other words, the guide extension 8b extends radially outward from the radially inner end of the magnet 9 by the same length L / 2 that is half the radial length L of the magnet 9.

  In addition, outer extending portions 8e that extend radially outward (to the vicinity of the outer periphery of the rotor core 8) from both ends in the circumferential direction are formed at the radially outer ends of the receiving holes 8a of the rotor core 8 of the present embodiment. ing.

Next, characteristic effects of the above embodiment will be described below.
(1) A guide extending portion 8b that extends outward in the circumferential direction from the circumferential end of the magnet 9 and extends radially outward from the radially inner end of the magnet 9 is formed at the radially inner end of the accommodation hole 8a. Therefore, the magnetic path of the leakage flux on the radially inner side of the magnet 9 becomes longer, and the magnetic flux (see arrow A in the figure) is guided radially outward to the radially outer end of the guide extension 8b. . Therefore, the leakage magnetic flux (magnetic flux heading from the N pole to the S pole immediately on the radially inner side of the magnet 9) is reduced and the effective magnetic flux is increased. As a result, the motor efficiency of the embedded magnet type motor can be increased.

  (2) Since the inner wall of the guide extension 8b on the radially outer side (side closer to the outer periphery of the rotor core 8) has a curved surface 8c that goes radially outward from the circumferential end of the magnet 9 toward the outer side in the circumferential direction. The magnetic flux (see arrow A in the figure) is smoothly guided radially outward along the curved surface 8c.

  (3) Since the guide extension 8b extends radially outward to the radial center position X of the magnet 9, the guide extension 8b is a magnetic flux from the radial inner side of the magnet 9 in the radial direction. If there is no shape, the magnetic flux going from the radially inner side to the other pole of the magnet 9 is guided radially outward from the radial center position X of the magnet 9.

  (4) Since the radially extending end 8e is formed at the radially outer end of the accommodation hole 8a from the both ends in the circumferential direction so as to extend radially outward (to the vicinity of the outer periphery of the rotor core 8). The leakage flux on the outside is reduced and the effective flux is increased.

The above embodiment may be modified as follows.
In the above embodiment, the guide extension 8b extends radially outward from the circumferential end of the magnet 9 to the radially inner end of the receiving hole 8a and more radially from the radially inner end of the magnet 9. If it is formed to extend outward, it may be changed to another shape.

  For example, you may change to the guide extension part 8f shown in FIG. The guide extension 8f has a curved surface 8g whose inner wall on the radially outer side (side closer to the outer periphery of the rotor core 8) is directed radially outward from the circumferential end of the magnet 9 toward the outer side in the circumferential direction. . Moreover, although the guide extension part 8b of the above-mentioned embodiment is assumed to have a constant width, the guide extension part 8f in this example has a width in the radial direction toward the outer side in the circumferential direction from the circumferential end part of the magnet 9. Has been widely used. Specifically, the guide extension 8f is a radial position constant surface 8h in which the radial position (distance from the shaft center) of the inner wall on the radially inner side (side closer to the inner periphery of the rotor core 8) is substantially constant. Thus, the width in the radial direction is increased from the circumferential end of the magnet 9 toward the outer side in the circumferential direction. In this way, the guide extension portion 8f does not protrude radially inward (in other words, the radial extension of the substantially annular portion 8i on the radially inner side of the rotor core 8 is kept substantially constant in the circumferential direction). It is possible to further increase the magnetic path of the leakage magnetic flux by increasing the radial width of the installation portion 8f. Therefore, while maintaining the rigidity of the rotor core 8, the leakage magnetic flux is further reduced and the effective magnetic flux is further increased.

  In this example (see FIG. 2), the guide extending portions 8f in the accommodation holes 8a adjacent to each other in the circumferential direction are parallel surfaces 8j in which inner walls facing each other in the circumferential direction are parallel to each other. By doing so, the width of the magnetic path of the leakage magnetic flux extending in the radial direction (the bridge portion 8k between the parallel surfaces 8j) can be made constant (as viewed from the axial direction). Therefore, the leakage magnetic flux is further reduced and the effective magnetic flux is further increased.

  In addition, although the guide extending portion 8b (see FIG. 1) of the above-described embodiment extends radially outward to the radial center position X of the magnet 9, it is not limited to this. As shown in FIG. 2, the magnet 9 may extend radially inward from the radial center position. The guide extending portion 8f of this example has a distal end that is about 1/4 of the radial length L of the magnet 9 (see FIG. 1) (L / 4). Extends radially outward from the portion.

  Further, although the guide extension portions 8b and 8f of the above-described embodiment and the other examples have the curved surfaces 8c and 8g, they are not limited to this, for example, radially outward (side closer to the outer periphery of the rotor core 8). The inner wall of the magnet 9 may first extend outward in the circumferential direction from the circumferential end of the magnet 9, and may be bent substantially at a right angle so as to extend radially outward from the radially inner end of the magnet 9.

  In the above embodiment, the outer extending portion 8e is formed at the radially outer end of the accommodation hole 8a. However, the present invention is not limited to this, and the outer extending portion 8e may have other shapes (for example, The shape may be changed to a shape extending outward in the circumferential direction, or the outer extending portion 8e may not be formed.

  In the above embodiment, the rotor core 8 is formed by laminating the core sheets in the axial direction, but is not limited to this, and is formed by other methods (for example, sintered by sintering magnetic powder) Core).

  -You may change the number of the teeth 4 of the said embodiment, the number of the accommodation holes 8a, the magnet 9, etc. to another number.

The top view of the stator and rotor of an embedded magnet type motor in this Embodiment. The top view of the rotor in another example.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 2 ... Rotor, 8 ... Rotor core, 8a ... Accommodating hole, 8b, 8f ... Guide extension part, 8c, 8g ... Curved surface, 8j ... Parallel surface, 9 ... Magnet, X ... Radial center position.

Claims (5)

An embedded magnet type rotating electrical machine including a rotor core that has a rotor core that penetrates in the axial direction and extends in the circumferential direction and that has a plurality of radially extending receiving holes, the magnet being disposed in the receiving hole,
A radially inner end portion of the receiving hole extends radially outward from the circumferential end portion of the magnet so as to have a radial width from the circumferential end thereof, and more radially than the radially inner end portion of the magnet. A guide extension extending to the outside is formed ,
An embedded magnet type rotating electrical machine characterized in that an outer extending portion extending radially outward from both ends in the circumferential direction is formed at a radially outer end of the accommodation hole . In the interior magnet type rotating electric machine according to claim 1,
The inner wall on the radially outer side of the guide extension portion has a curved surface that goes to the outer side in the radial direction from the circumferential end of the magnet toward the outer side in the circumferential direction. In the interior magnet type rotating electric machine according to claim 2,
An embedded magnet type rotating electrical machine characterized in that the guide extending portion has a radial width wider toward the outer side in the circumferential direction than a circumferential end portion of the magnet. In the embedded magnet type rotating electric machine according to claim 3,
In the embedded magnet type rotating electrical machine, the guide extending portions in the accommodation holes adjacent in the circumferential direction have parallel surfaces of the adjacent inner walls facing each other in the circumferential direction. The interior permanent magnet type rotating electrical machine according to any one of claims 1 to 4,
The guide extension portion extends radially outward to a radial center position of the magnet.

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