JP2001218398A - Rotor for permanent magnet-type motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rotor, for a permanent magnet-type motor, in which the motor characteristic is improved by effectively using a permanent magnet which is buried in a rotor core. SOLUTION: The rotor 9 for the permanent magnet-type motor is formed with slots 66 formed in the axial direction, to correspond to respective magnetic poles at the inside ot the nearly cylindrical rotor core 63 and that permanent magnets MG are buried in the respective slots. The permanent magnets are magnetized in the magnetic orientation, in which the magnetic flux of each part is concentrated at one focus P2. Edge parts on the surface side of the rotor core of the permanent magnets are directed nearly to the focus.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotor of a permanent magnet type motor used for driving a compressor mounted on, for example, an air conditioner or a refrigerator.

[0002]

2. Description of the Related Art A conventional rotor of this type of permanent magnet type motor has a rotor core formed by laminating rotor iron plates made of electromagnetic steel plates, as disclosed in, for example, Japanese Patent Application Laid-Open No. 8-331783. It is constructed by embedding a permanent magnet in the device. In this case, the rotor has a substantially coaxial cylindrical shape with the substantially cylindrical stator, has, for example, four magnetic poles facing the inner peripheral surface of the stator, and freely rotates around an axis. It is configured as follows.

In this rotor core, two arc-shaped slots for embedding permanent magnets projecting inward from the inner circumference are formed per pole, in this case, two layers in the radial direction, and permanent magnets of the same shape are embedded in the slots. Is done. The rotor rotates when a magnetic pole attracts or repels a rotating magnetic field generated by a winding wound on a stator.

FIG. 19 is a plan view of a rotor 100 of a conventional permanent magnet type motor as disclosed in the above publication. FIG. 19 shows only の み of the rotor, and in this case, the slot 10
1 is formed in one layer. In this figure, slot 1
01 is formed in the axial direction corresponding to the four magnetic poles of the rotor 100. As described above, the slot 101 has a circular arc shape in which the inner peripheral edge 101A of the rotor core 102 is convex, and the outer peripheral side has a substantially linear shape.

[0005] With such a shape, the rotor core 1
02 can maximize the cross-sectional area of the slot 101,
Accordingly, the size of the permanent magnet MG inserted into the slot 101 can be increased. The permanent magnet MG is configured by, for example, inserting a ferrite material into the slot 101 and then magnetizing the magnet. By increasing the size, the magnet torque is increased.

In this case, the magnetization of the permanent magnet MG is magnetically oriented such that the magnetic flux is concentrated at a point outside the slot 101 as a focal point P2 as shown by a broken line and an arrow in FIG.

[0007]

However, since the shape and the magnetic orientation of the permanent magnet MG have not been specified in the prior art, the rotor core 102 shown in FIG.
Of the permanent magnet MG (hatched M
G1) protruded from the outermost magnetic flux in some cases.

As described above, when the relationship between the magnetic orientation and the permanent magnet MG is such that the permanent magnet MG protrudes from the magnetic flux concentrated at the focal point P2, the portion of the MG1 becomes ineffective and does not contribute to the motor performance at all. was there.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional technical problem, and a permanent magnet type in which a permanent magnet embedded in a rotor core is effectively used to improve motor characteristics. It is an object to provide a rotor for a motor.

[0010]

The rotor of the permanent magnet type motor according to the present invention has axially formed slots corresponding to respective magnetic poles inside a substantially cylindrical rotor core. Each permanent magnet is embedded, the permanent magnet is magnetized in a magnetic orientation where the magnetic flux of each part is concentrated at one focal point, and the edge of the permanent magnet on the rotor core surface side is It is characterized by being substantially directed to the focal point.

In the rotor of the permanent magnet type motor according to the second aspect of the present invention, the slot and the inner peripheral side edge of the rotor core of the permanent magnet inserted into the slot are convex on the inner peripheral side of the rotor core. It is characterized by having an arc shape.

According to the present invention, slots are formed in the substantially cylindrical rotor core in the axial direction corresponding to the respective magnetic poles,
In a rotor of a permanent magnet type motor in which a permanent magnet is embedded in each slot, the permanent magnet is magnetized in a magnetic orientation in which the magnetic flux of each part is concentrated at one focal point, and a rotor core of the permanent magnet is used. Since the front edge is substantially directed to the focal point, an ineffective portion of the permanent magnet that does not contribute to motor performance is eliminated, and the motor performance can be improved by effectively using the magnetic flux of the permanent magnet. .

[0013]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a vertical sectional side view of a hermetic compressor C as an embodiment to which the present invention is applied. In this figure, reference numeral 1 denotes a closed container, in which two frames 2 and 3, a compression element 4 disposed on the upper side of the frames 2 and 3, and a lower portion are disposed. A motor (permanent magnet type motor; electric element) 5 is housed. The compression element 4 and the motor 5 are assembled together to form a compression main body 17, which is elastically attached to the inner wall of the closed casing 1 via the support device 6.

The motor 5 includes a stator 8 having a stator winding 7 therein, and a rotor 9 disposed inside the stator 8.
And the bearing 10 of the frame 2 inserted into the center of the rotor 9
And the rotating shaft 11 which is supported by the shaft.

The compression element 4 includes a cylinder 12, a piston 14 fitted in a crank pin 13 of a rotary shaft 11 in the cylinder 12 and reciprocally sliding, a valve seat 15 provided on an end face of the cylinder 12, Cylinder 1 via valve seat 15
2 and a cylinder head 16 attached to the cylinder head 2. The cylinder head 16 is fixed to the cylinder 12 by bolts 18.

An ester oil is sealed in the closed container 1 as a lubricating oil. The hermetic compressor C forms a refrigeration cycle of a refrigerator (not shown), and is filled with an HFC refrigerant such as R-134a, for example. Then, the rotation of the rotor 7 of the motor 5 causes the piston 14 of the compression element 4 to slide back and forth, thereby performing an operation of sucking, compressing, and discharging the refrigerant.

Next, the motor 2 will be described in detail. The motor 2, which is an electric element of the hermetic compressor C, is a so-called magnetic pole concentrated winding type DC brushless motor, and the stator 8 fixed to the inner wall of the hermetic container 1 via a frame 3 and a supporting device 6. And the rotor 9 rotatably supported inside the stator 8 about the rotation shaft 11.

First, FIGS. 2 to 5 show the stator 8. As shown in FIG. 6, the stator 8 has a stator core 22 formed by laminating a plurality of substantially rectangular donut-shaped stator iron plates (electromagnetic steel plates such as silicon steel plates) 21, and a rotating magnetic field to the rotor 9. The stator winding (drive coil) for providing
7, and insulators (insulating materials) 23 and 24 provided between the stator winding 7 and the stator core 22.

Six teeth 26 are provided on the inner periphery of the stator core 22. Six slots 27 are formed between the teeth 26 inwardly and vertically. A tip 26A is formed at the tip of the tooth 26 so as to extend along the outer surface of the rotor 9. Then, the stator winding 7 is directly wound around each tooth 26 through the insulators 23 and 24 by utilizing the space of the slot 27 so that the stator 8 is formed by a so-called concentrated series winding method.
To form a stator 8 having four poles and six slots.

In this case, a plurality of stator iron plates 21 are stacked and caulked and fixed to each other at caulking portions 31 located at the four corners of each stator iron plate 21. afterwards,
The outer four sides 22 on which the end faces of the stator iron plates 21 are located
The stator core 22 is formed by welding central portions of A, 22B, 22C, and 22D to each other (welding portions are indicated by Y).

Thus, the outer four sides 2 of the stator core 22 are
2A to 22D are mutually welded (Y) to the center of the end face of each of the stator iron plates 21..., And the heat applied to each of the stator iron plates 21. The stator iron plate 21 which is generated by heat during welding because it is uniformly diffused in the part direction (stator iron core 22)
Can be prevented beforehand.

Further, the stator core 22 is formed by caulking portions 3 at four corners.
.. And the center of the four sides 22A to 22D located therebetween is fixed by welding, so that the stator iron plates 21 are efficiently integrated, and the stator iron cores 22 are formed. The strength of itself is also improved.

Next, each of the insulators 23 and 24 is molded from PBT (polybutylene terephthalate; hard synthetic resin), enters into the slot portion 27 of the stator core 22, and comes into contact with the outer surface of the tooth portion 26. The comb-shaped engaging portions 33 shown in FIGS.
.. Are formed at six places, and outer end portions 36 and 37 are provided at one end of each of the comb-like engaging portions 33. Inner annular portions 38, 39 located axially outside the tip portions 26A of the teeth 26 of the stator core 22 are integrally formed.

Here, FIG. 10 shows a plan view of one of the insulators 23. FIG. On the outer surface of the outer annular portion 36 of the insulator 23, a plurality of engaging portions 41 whose tips are expanded are integrally formed at predetermined intervals so as to protrude. , The comb-shaped engaging portion 33.
A plurality of cutouts 42 cut from the end face on the opposite side are formed.

As shown in FIG. 12, a substantially T-shaped engaging portion 43 is integrally formed on the outer surface of the outer annular portion 36 so as to protrude outward. Protrusions 44, 44 erected on the opposite side to the comb-shaped engaging portion 33 are formed integrally. Both ends of the engaging portion 43 are slightly bent toward the outer annular portion 36, so that both sides of the engaging portion 43 have insertion portions 47 each formed of a substantially circular curved surface with a part of the outside cutout. , 47 are formed (FIG. 12). Further, the outer annular portion 3 near the engaging portion 43
From 6, a pressing projection 46 is integrally formed.

The outer annular portion 37 of the other insulator 24
A plurality of holding portions 51 extending in the horizontal direction are integrally formed on the outer surface of the device. A plurality of rows (two rows in the embodiment) of the holding portions 51 are spaced from each other in the width direction of the outer annular portion 37.
The outer annular portion 37 is formed so as to be shifted in the radial direction so as not to overlap in the width direction of the outer annular portion 37.
Thereby, when the insulator 24 is molded, there is no problem even when the mold is pulled out in the extending direction of the comb-shaped engaging portions 34. Further, the outer annular portion 37
Also, a plurality of notches 52 cut from the end face opposite to the comb-like engaging portions 34 are formed.

Such insulators 23 and 24 are
The stator core 22 is fitted from both ends in the axial direction.
At this time, the comb-shaped engaging portions 3 of the insulators 23 and 24
, 34 ... enter the respective slot portions 27 ... of the stator core 22 and engage with the teeth 26 ... outer surfaces.

Here, each of the comb-like engaging portions 33 of the insulator 23 is tapered so that the tip thereof becomes thin, and the insulators 23 and 24 are connected from both ends of the stator core 22 to the stator core 22. In the fitted state, the comb-shaped engaging portions 33 of the insulator 23 enter the opposing comb-shaped engaging portions 34 of the other insulator 24 from the tip thereof, as shown in FIG. Duplicate.

The overlap margin (overlap dimension) ranges from a state in which the comb-like engaging portion 33 enters the comb-like engaging portion 34 shallowly as shown in FIG. 8 to a state in which the comb-like engaging portion 33 enters deeply as shown in FIG. Is acceptable. Therefore, when the number of stacked stator iron plates 21 is large, that is, in the case of a model having a large stack thickness of the stator core 22, the overlap margin is reduced as shown in FIG.
When the number of laminations of 1... Is small, that is, the stator core 2
In the case of a model with a small stack thickness of 2, the overlap margin increases as shown in FIG. That is, the insulators 23 and 24 are configured so that they can be used for the stator cores 22 having various thicknesses, and are extremely versatile. Further, the comb-shaped engaging portion 33 of the insulator 23 has a tapered shape, so that the insulator 24 can be smoothly inserted into the comb-shaped engaging portion 34.

After fitting the insulators 23 and 24 to the stator core 22 in this way, as described above, each tooth 26.
The stator winding 7 is directly wound by utilizing the space of the slot portion 27 to constitute the concentrated pole-wound four-pole six-slot stator 8.

In this case, the stator windings 7 wound around the opposing teeth 26, 26 have one phase, and the stator 8 has the three-phase stator windings 7 wound thereon. Therefore, the stator windings 7 wound around the opposed tooth portions 26, 26 are connected to each other by a crossover wire 53 on the insulator 24 side, and further, the stator windings 7 of each phase are connected on the insulator 23 side. Thus, a three-phase neutral point is formed.

The crossover wires 53 of each phase are drawn out of the notch 52 of the insulator 24 as shown in FIG. 5 to be along the outer surface of the outer annular portion 37, and as shown in FIG. It is drawn around with 51. Since the crossovers 53 are held in a separated state by these holding portions 51 (FIG. 3), short-circuit failure due to contact of the crossovers 53 of each phase is prevented beforehand. .

On the other hand, on the insulator 23 side, a lead wire 54 is connected to the stator winding 7 of each phase.
The lead wires 54 are covered with an insulating material, drawn out from the cutout portions 42 of the outer annular portion 36 of the insulator 23 as shown in FIG. After being finally combined into one by the coating 56, it is connected to the connector 57 at the end.

In this case, each of the lead wires 54... Passes under the holding projection 46 in front of the covering 56, and the combined covering 56 is formed on the stator core 22 side of the engaging portion 43. To pass through the insertion portion 47 and
(See FIG. 2 and FIG. 4) so as to reach the connector 57 (connected to a terminal (not shown) for supplying power). As described above, the engaging portions 41... And the engaging portions 43 that support the lead wires 54. .. Can be held along the outer surface of the outer annular portion 36 of the insulator 23 without attaching a cover or the like.

Reference numeral 58 denotes an insulating tubular member which is inserted between the adjacent stator windings 7 in the slot 27. Then, a connection portion between the wound stator winding 7 and the lead wire 54 is inserted and held in the cylindrical member 58. Reference numeral 59 denotes a neutral wire for mutually connecting the stator windings 7 of the opposed tooth portions 26 of each phase. Then, similarly, it is pulled out from the notch portion 42 and drawn around the lower side of the engaging portion 41, whereby the outer surface of the outer annular portion 36 is formed. Reference numeral 61 denotes a similar tubular member into which the connection portion of the neutral wire 59 is similarly inserted.

Next, the rotor 9 will be described in detail. 6
Reference numeral 3 denotes a rotor iron core of the rotor 9, which is formed, for example, by a magnetic steel sheet having a thickness of 0.3 mm to 0.7 mm as shown in FIG.
A plurality of rotor iron plates 64 punched in a circular shape as described above are laminated, caulked together, and laminated integrally.

Slots 66... Are formed in the rotor core 63 in the axial direction corresponding to the four magnetic poles, and ferrite permanent magnets M are provided in these slots 66.
G is inserted. The rotor core 63 is integrated with a rivet (not shown) in a state where the end face member 67 is put on the end face in the axial direction. The permanent magnet MG is magnetized after being inserted into the slot 66 as described later.
In FIG. 15, reference numeral 68 denotes a hole for inserting the rivet.

Here, the inner peripheral edge 66A of the rotor core 63 of each slot 66... Has an arc shape that is convex on the inner peripheral side, and the outer peripheral side has a substantially linear shape. Shape. With such a shape, the rotor core 6
3 can maximize the cross-sectional area of the slot 66, and thereby the permanent magnet MG inserted into the slot 66
, The magnet torque can be increased.

As shown in FIG. 16, the edge 66B of the slot 66 on the surface side of the rotor core 63 is
And the corner P1 formed by the edge 66B on the front surface side and the edge 66A on the inner peripheral side is 0.1 mm.
It is an arc shape having an extremely small diameter of 4R or less. The corners P1, P1 of the slots 66, 66 of the magnetic poles adjacent to each other are brought into contact with each other on the surface side of the rotor core 63, but by forming the corner P1 into a minute arc shape,
Rotor core 63 interposed between adjacent corners P1, P1
Becomes smaller (in plan view). As a result, the leakage flux generated between the magnetic poles is significantly reduced.

On the other hand, the inner peripheral edge 66A of the slot 66
Also, as it approaches the corner P1, it approaches the edge 66A of the adjacent slot 66, and the edge 66A has a flat portion 69 having a predetermined width formed in a portion continuous with the corner P1. Thereby, the space between the adjacent slots 66, 66 does not narrow at one point, and the strength of the rotor core 63 is maintained at the flat portion 69.

Next, the magnetization of the permanent magnet MG will be described with reference to FIG. As described above, the magnetization of the permanent magnet MG is performed in this state after the ferrite material is inserted into the slot 66 of the rotor core 63.
As shown by a broken line and an arrow in FIG. 17, one point outside the slot 66 is set as a focal point P2 so that magnetic flux is concentrated.

Further, an edge 66B of the slot 66 on the surface of the rotor core 63 is set so as to be substantially directed to the focal point P2 (indicated by L1 in FIG. 17). Thereby, the permanent magnet M
The edge on the surface side of the rotor core 63 of G is also substantially directed to the focal point P2, and there is almost no portion of the edge protruding outward from the magnetic flux (L1) concentrated on the focal point P2. Therefore, the ineffective portion of the permanent magnet MG is minimized, and the magnetic flux is effectively used.
Are significantly improved.

In the slot of the embodiment, the rotor core 6
3 was flattened on the outer peripheral side, but not limited thereto.
As shown in FIG. 8, the outer peripheral edge 66C may have the same arc shape as the inner peripheral edge. However, the relationship between the magnetic orientation and the edge 66B must be the same as in FIG.

In the embodiment, the present invention is applied to a motor for driving a compressor. However, the present invention is not limited to this, and the present invention is effective for various permanent magnet motors such as a blower driving motor.

[0045]

As described above in detail, according to the present invention, slots are formed in the substantially cylindrical rotor core in the axial direction corresponding to the respective magnetic poles, and each slot has a permanent magnet embedded therein. In the rotor of the permanent magnet type motor formed as described above, the permanent magnet is magnetized in a magnetic orientation in which the magnetic flux of each part is concentrated on one focal point, and the edge of the permanent magnet on the rotor core surface side is focused on the focal point. Since the permanent magnet is substantially oriented, an ineffective portion of the permanent magnet that does not contribute to motor performance is eliminated, and the motor performance can be improved by effectively utilizing the magnetic flux of the permanent magnet.

[Brief description of the drawings]

FIG. 1 is a vertical sectional side view of a hermetic compressor according to an embodiment to which the present invention is applied.

FIG. 2 is a perspective view of a stator of the motor of the hermetic compressor of FIG. 1;

FIG. 3 is a rear perspective view of the stator of FIG. 2;

FIG. 4 is a plan view of a motor of the hermetic compressor of FIG. 1;

FIG. 5 is a rear view of the motor of FIG. 4;

FIG. 6 is a plan view of a stator core of the motor of FIG. 4;

FIG. 7 is a side view of the stator core of FIG. 6;

FIG. 8 is a side view of the insulator of the stator of FIG. 2;

FIG. 9 is a side view of the insulator of the stator of FIG. 2;

FIG. 10 is a plan view of one insulator of FIG. 8;

FIG. 11 is a front view of a supporting portion of the insulator of FIG. 10;

FIG. 12 is a plan view of an engaging portion of the insulator of FIG. 10;

FIG. 13 is a sectional view of an engaging portion of the insulator of FIG. 10;

FIG. 14 is a perspective view of a rotor core of a rotor of the motor of the hermetic compressor of FIG. 1;

FIG. 15 is a plan view of the rotor core of FIG. 14;

FIG. 16 is an enlarged plan view of a half of the rotor core of FIG. 15;

FIG. 17 is a diagram showing a magnetized state of a rotor of a motor of the hermetic compressor of FIG. 1;

FIG. 18 is a view showing another embodiment of the rotor corresponding to FIG. 17;

FIG. 19 is a diagram showing a shape and a magnetized state of a permanent magnet of a conventional rotor.

[Explanation of symbols]

 C Compressor 1 Airtight container 4 Compressor 5 Motor 7 Stator winding 8 Stator 9 Rotor 11 Rotating shaft 63 Rotor core 66 Slot 66A, 66B Edge MG Permanent magnet P2 Focus

 ────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoshihiko Nagase 2-5-5 Keihanhondori, Moriguchi-shi, Osaka Sanyo Electric Co., Ltd. F-term (reference) 5H002 AA05 AB07 AC03 AC06 AE08 5H621 GA01 GA04 GB09 GB10 GB14 HH01 5H622 AA03 CA02 CA13 CB04 CB05 PP03 PP10 PP11 PP14 PP16 QB05

Claims (2)

[Claims] In a rotor of a permanent magnet type motor, a slot is formed in a substantially cylindrical rotor core in an axial direction corresponding to each magnetic pole, and a permanent magnet is embedded in each slot. The permanent magnet is magnetized in a magnetic orientation in which the magnetic flux of each part is concentrated at one focal point, and the edge of the permanent magnet on the rotor core surface side is substantially directed to the focal point. A rotor for a permanent magnet type motor. 2. The rotor core according to claim 1, wherein the inner peripheral edge of the rotor core of the slot and the permanent magnet inserted therein has an arc shape that is convex on the inner peripheral side of the rotor core. Rotor of permanent magnet type motor.