JP3679673B2 - Permanent magnet motor rotor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a rotor of a permanent magnet type motor used for driving a compressor or the like mounted in, for example, an air conditioner or a refrigerator.
[0002]
[Prior art]
A conventional rotor of this type of permanent magnet type motor has a permanent magnet embedded in a rotor core formed by laminating rotor iron plates made of electromagnetic steel plates as disclosed in, for example, Japanese Patent Laid-Open No. 8-331784. It consists of In this case, the rotor has a cylindrical shape substantially coaxial with the substantially cylindrical stator, has, for example, four magnetic poles facing the inner peripheral surface of the stator, and freely rotates around the axis. It is configured as follows.
[0003]
In this rotor core, a circular arc-shaped permanent magnet embedding slot convex on the inner peripheral side is formed per layer in this case in two layers in the radial direction, and the same shape permanent magnet is embedded in this slot. The rotor rotates when a magnetic pole is attracted or repelled by a rotating magnetic field generated by a winding mounted on the stator.
[0004]
FIG. 19 is a plan view of a rotor 100 of a conventional permanent magnet type motor as described in the above publication. FIG. 19 shows only a quarter of the rotor, and in this case, one slot 101 is formed. In this figure, the slot 101 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 edge 101A on the inner peripheral side of the rotor core 102 is convex, and the outer peripheral side has a substantially linear shape.
[0005]
By adopting such a shape, the cross-sectional area of the slot 101 in the rotor core 102 can be enlarged to the maximum, and thereby the permanent magnet MG inserted into the slot 101 can be enlarged. The permanent magnet MG is configured, for example, by magnetizing after inserting a ferrite material into the slot 101, and the magnet torque is increased by increasing the size in this way.
[0006]
In this case, the permanent magnet MG was magnetized so that the magnetic flux was concentrated with one point outside the slot 101 as the focal point P2, as indicated by the broken line and the arrow in the figure.
[0007]
[Problems to be solved by the invention]
However, since the shape and magnetic orientation of the permanent magnet MG have not been defined conventionally, the edge (indicated by hatching MG1) of the permanent magnet MG located on the surface side of the rotor core 102 is the outermost side as shown in FIG. Sometimes protruded from the magnetic flux.
[0008]
As described above, when the relationship between the magnetic orientation and the permanent magnet MG is in a state where the permanent magnet MG protrudes from the magnetic flux concentrated at the focal point P2, the portion of the MG1 becomes invalid and does not contribute to the motor performance at all. .
[0009]
The present invention has been made to solve the above-described conventional technical problems, and is a rotation of a permanent magnet type motor in which motor characteristics are improved by effectively using a permanent magnet embedded in a rotor core. The purpose is to provide children.
[0010]
[Means for Solving the Problems]
The rotor of the permanent magnet type motor according to the present invention is formed by forming slots in the axial direction corresponding to the magnetic poles in a substantially cylindrical rotor core, and embedding permanent magnets in the slots. The permanent magnet is magnetized in a magnetic orientation in which the magnetic flux of each part concentrates on one focal point, and the edge of the permanent magnet on the rotor core surface side is substantially directed to the focal point. It is characterized by.
[0011]
In the rotor of the permanent magnet type motor of the invention of claim 2, the slot and the inner peripheral side edge of the rotor core of the permanent magnet inserted into the slot are arc-shaped so as to protrude toward the inner peripheral side of the rotor core. It is characterized by presenting.
[0012]
According to the present invention, a rotor of a permanent magnet type motor in which a slot is formed in the axial direction corresponding to each magnetic pole inside a substantially cylindrical rotor core, and a permanent magnet is embedded in each slot. In this case, 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 substantially directed to the focal point. The ineffective portion that does not contribute to the performance is eliminated, and the motor performance can be improved by effectively using the magnetic flux of the permanent magnet.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 shows a longitudinal side view of a hermetic compressor C as an embodiment to which the present invention is applied. In this figure, 1 is an airtight container, and in this container, the frame bodies 2 and 3 which consist of two parts, the compression element 4 arrange | positioned above this frame bodies 2 and 3, and the lower side are arrange | positioned. A motor (permanent magnet type motor; electric element) 5 is accommodated. The compression element 4 and the motor 5 are assembled together to form a compression main body 17, and the main body 17 is elastically attached to the inner wall of the hermetic container 1 via the support device 6.
[0014]
The motor 5 includes a stator 8 having a stator winding 7 therein, a rotor 9 disposed inside the stator 8, and a bearing 10 of the frame body 2 that is inserted into the center of the rotor 9. The rotary shaft 11 is supported by the rotary shaft 11.
[0015]
The compression element 4 includes a cylinder 12, a piston 14 that is fitted in the crank pin 13 of the rotary shaft 11 and reciprocally slides in the cylinder 12, a valve seat 15 provided on an end surface of the cylinder 12, and the valve seat 15 And a cylinder head 16 attached to the cylinder 12 via the cylinder. The cylinder head 16 is fixed to the cylinder 12 by bolts 18.
[0016]
An ester-based oil is enclosed in the sealed container 1 as a lubricating oil. Further, the hermetic compressor C constitutes a refrigeration cycle of a refrigerator (not shown). As a refrigerant to be used, for example, an HFC refrigerant such as R-134a is filled. Then, the piston 14 of the compression element 4 is reciprocated by the rotational drive of the rotor 7 of the motor 5, and the operation of sucking, compressing and discharging the refrigerant is performed.
[0017]
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 the frame 3 and the support device 6. And the rotor 9 supported inside the stator 8 so as to be rotatable about the rotating shaft 11.
[0018]
First, FIGS. 2 to 5 show the stator 8. As shown in FIG. 6, the stator 8 includes a stator core 22 formed by laminating a plurality of substantially rectangular donut-shaped stator iron plates (magnetic steel plates such as silicon steel plates) 21, and a rotating magnetic field applied to the rotor 9. The stator winding (driving coil) 7 to be provided and insulators (insulating materials) 23 and 24 interposed between the stator winding 7 and the stator core 22 are provided.
[0019]
Six tooth portions 26 are provided on the inner periphery of the stator core 22, and six slot portions 27 opened inwardly and vertically are formed between the tooth portions 26. A distal end portion 26 </ b> A that is widened along the outer surface of the rotor 9 is formed at the distal end of the rotor 26. Then, by winding the stator winding 7 directly on each tooth portion 26... Via the insulators 23, 24 using the space of the slot portion 27, the stator 8 can be wound by a so-called concentrated direct winding method. A magnetic pole is formed to constitute a stator 8 with four poles and six slots.
[0020]
In this case, a plurality of stator iron plates 21 are stacked, and are fixed to each other at the crimping portions 31... Positioned at the four corners of each stator iron plate 21. Then, the stator core 22 is comprised by welding the center part of the outer four sides 22A, 22B, 22C, and 22D where the end faces of the stator iron plates 21 are located to each other (welding points are indicated by Y). ing.
[0021]
Thus, since the center part of the end surface of each stator iron plate 21 ... which comprises the outer four sides 22A-22D of the stator iron core 22 was welded (Y) to each other, each stator iron plate 21 ... was welded during welding. The applied heat is evenly diffused in the direction of the four corners of the stator iron plate 21... To prevent distortion of the stator iron plate 21... (Stator core 22) caused by heat during welding. Is possible.
[0022]
In addition, the stator core 22 is caulked by the caulking portions 31... At the four corners, and the centers of the four sides 22A to 22D located therebetween are welded and fixed. It is efficiently integrated and the strength of the stator core 22 itself is improved.
[0023]
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 close contact with the outer surface of the tooth portion 26. The comb-like engaging portions 33... 34 shown in FIG. 8 and FIG. 9 to be fitted are formed in six places, and the comb-like engaging portions 33. 34... On one end side of each of the outer annular portions 36 and 37, and on the inner side thereof, an inner annular portion 38 positioned on the outer side in the axial direction of the distal end portion 26 A of each tooth portion 26. 39 are integrally formed with each other.
[0024]
Here, the top view of one insulator 23 is shown in FIG. On the outer surface of the outer annular portion 36 of the insulator 23, a plurality of support portions 41 whose tips are spread out are formed integrally with a predetermined interval, and the outer annular portion 36 located in the vicinity thereof is formed on the outer annular portion 36. A plurality of cutout portions 42 are formed by cutting from the end surface opposite to the comb-like engagement portions 33.
[0025]
Further, as shown in FIG. 12, a support portion 43 having a substantially T-shape is integrally formed on the outer surface of the outer annular portion 36 so as to protrude outward. Protrusions 44, 44 erected on the side opposite to the joint portion 33 are integrally formed. Then, both sides of the front end of the support portion 43 are bent slightly toward the outer annular portion 36, whereby an insertion portion 47 composed of a substantially circular curved surface with a part of the outside cut out on both side surfaces of the support portion 43. 47 are formed (FIG. 12). Further, a pressing protrusion 46 is integrally formed so as to protrude from the outer annular portion 36 in the vicinity of the engaging portion 43.
[0026]
A plurality of holding portions 51 extending in the horizontal direction are integrally formed on the outer surface of the outer annular portion 37 of the other insulator 24. Each holding portion 51... Is formed in a plurality of rows (two rows in the embodiment) at intervals in the width direction of the outer annular portion 37, and is arranged so as not to overlap in the width direction of the outer annular portion 37. The annular portion 37 is formed so as to be shifted in the radial direction. Thereby, when the insulator 24 is molded, it is configured not to cause any trouble even when the mold is pulled out in the extending direction of the comb-like engagement portions 34. Further, the outer annular portion 37 is also formed with a plurality of cutout portions 52 cut from the end surface opposite to the comb-like engagement portions 34.
[0027]
Such insulators 23 and 24 are fitted to the stator core 22 from both axial ends thereof. At this time, the comb-like engaging portions 33,..., 34... Of the insulators 23, 24 enter into the respective slot portions 27. Match.
[0028]
Here, each comb-like engaging portion 33... Of the insulator 23 has a tapered shape with a thin tip, and the insulators 23 and 24 are fitted to the stator core 22 from both ends of the stator core 22. In this state, the comb-like engaging portions 33 of the insulator 23 enter into the respective comb-like engaging portions 34 of the other opposing insulator 24 from the tip and overlap as shown in FIG.
[0029]
This overlapping margin (overlapping dimension) is allowed in an arbitrary range from a state where the comb-like engaging portion 33 enters shallowly into the comb-like engaging portion 34 as shown in FIG. 8 to a state where it enters deeply as shown in FIG. The Therefore, when the number of stacked stator iron plates 21... Is large, that is, in the case of a model having a large stack of stator cores 22, the overlapping margin is reduced as shown in FIG. When the number of stacked layers is small, that is, when the thickness of the stator core 22 is small, the overlap margin increases as shown in FIG. That is, the insulators 23 and 24 are configured to be used for the stator cores 22 having various thicknesses, and are extremely versatile. Further, since the comb-like engaging portion 33 of the insulator 23 has a tapered shape, the insulator 24 can be smoothly inserted into the comb-like engaging portion 34.
[0030]
After the insulators 23 and 24 are thus fitted to the stator core 22, the stator winding 7 is directly wound around each tooth portion 26... Using the space of the slot portion 27 as described above. Thus, a concentrated pole-wound four-pole six-slot stator 8 is constructed.
[0031]
In this case, the stator winding 7 wound around the teeth 26 and 26 facing each other is one phase, and the stator 8 is wound with the three-phase stator winding 7. The stator windings 7 wound around the teeth 26, 26 facing each other are connected to each other by a jumper 53 on the insulator 24 side, and further, the stator windings 7 of the respective phases are connected to each other on the insulator 23 side. The neutral point of the phase is constructed.
[0032]
Further, as shown in FIG. 5, the crossover lines 53 of each phase are drawn out from the notch 52 of the insulator 24 and along the outer surface of the outer annular portion 37, and as shown in FIG. Is drawn around. Since each of the connecting wires 53 is held apart by these holding portions 51... (FIG. 3), a short circuit failure due to contact of the connecting wires 53. .
[0033]
On the other hand, on the insulator 23 side, lead wires 54 are connected to the stator windings 7 of the respective phases. The lead wires 54 are covered with an insulating material and drawn out from the notch 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.
[0034]
In this case, each of the lead wires 54... Is passed under the pressing projection 46 before the covering 56, and the covering 56 portion gathered as one loops around the stator core 22 side of the engaging portion 43. It passes through the insertion part 47, is supported by the protrusion 44, and is routed to reach the connector 57 (connected to a terminal (not shown) for supplying power) (FIGS. 2 and 4). As described above, since the support portions 41... For supporting the lead wires 54... And the support portions 43 and the pressing protrusions 46 (which function as a support portion) are formed on the insulator 23 as a pair, The lead wires 54 of the stator winding 7 can be held along the outer surface of the outer annular portion 36 of the insulator 23 without attaching a cover or the like.
[0035]
Reference numeral 58 denotes an insulating cylindrical member which is inserted between the adjacent stator windings 7 in the slot portion 27. A connecting 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 that interconnects the stator windings 7 of the teeth 26 and 26 facing each other. Similarly, it is pulled out from the notch portion 42 and drawn around the lower side of the support portion 41, thereby being along the outer surface of the outer annular portion 36. Reference numeral 61 denotes a similar cylindrical member into which the connecting portion of the neutral wire 59 is similarly inserted.
[0036]
Next, the rotor 9 will be described in detail. 63 is a rotor iron core of the rotor 9, and a plurality of rotor iron plates 64 punched in a circular shape as shown in FIG. 15 from a magnetic steel sheet having a thickness of 0.3 mm to 0.7 mm as shown in FIG. They are caulked together and laminated together.
[0037]
In the rotor core 63, slots 66... Are formed in the axial direction corresponding to the four magnetic poles, and ferrite permanent magnets MG are inserted into the slots 66. And it integrates with the rivet which is not illustrated in the state which covered the end surface member 67 on the end surface of the axial direction of the rotor core 63. As shown in FIG. As will be described later, the permanent magnet MG is magnetized after being inserted into the slot 66. In FIG. 15, reference numeral 68 denotes a hole for inserting the rivet.
[0038]
Here, the inner peripheral edge 66A of the rotor core 63 of each slot 66... Has an arcuate shape that protrudes toward the inner peripheral side, and the outer peripheral side has a substantially linear shape. Has been. By adopting such a shape, the cross-sectional area of the slot 66 in the rotor core 63 can be enlarged to the maximum, thereby increasing the permanent magnet MG inserted into the slot 66 and increasing the magnet torque.
[0039]
Further, as shown in FIG. 16, the edge 66B on the surface side of the rotor core 63 of the slot 66 has a shape substantially along the surface of the rotor core 63. The edge 66B and the inner peripheral side of this surface side The corner portion P1 formed by the edge portion 66A has an arc shape with a minimum diameter of 0.4R 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. The area (plan view) of the rotor core 63 interposed between the corners P1 and P1 is reduced. Thereby, the leakage magnetic flux generated between both magnetic poles is remarkably reduced.
[0040]
On the other hand, the edge 66A on the inner peripheral side of the slot 66 also approaches the edge 66A of the adjacent slot 66 as it approaches the corner P1, but this edge 66A is located at a portion continuous with the corner P1. A flat portion 69 having a predetermined width is formed. As a result, there is no narrowing between adjacent slots 66 and 66 at one point, and the strength of the rotor core 63 is maintained at the flat portion 69.
[0041]
Next, magnetization of the permanent magnet MG will be described with reference to FIG. As described above, the permanent magnet MG is magnetized in this state after the ferrite material is inserted into the slot 66 of the rotor core 63. At this time, as shown by the broken line and the arrow in FIG. The magnetic orientation is such that the magnetic flux concentrates at one point outside the focal point as the focal point P2.
[0042]
Further, the edge 66B on the surface side of the rotor core 63 of the slot 66 is set so as to be substantially directed to the focal point P2 (indicated by L1 in FIG. 17). As a result, the edge of the permanent magnet MG on the rotor core 63 surface side is also substantially directed to the focal point P2, and there is almost no portion of the edge that protrudes outward from the magnetic flux (L1) concentrated on the focal point P2. Become. Therefore, the ineffective portion of the permanent magnet MG is minimized, the magnetic flux is effectively used, and the characteristics of the motor 5 are remarkably improved.
[0043]
In the slot of the embodiment, the outer peripheral edge of the rotor core 63 is flat. However, the present invention is not limited to this, and the outer peripheral edge 66C has an arc shape similar to that of the inner peripheral as shown in FIG. Also good. However, the relationship between the magnetic orientation and the edge 66B needs to be the same as in FIG.
[0044]
In the embodiments, 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 type motors such as a blower driving motor.
[0045]
【The invention's effect】
As described above in detail, according to the present invention, a slot is formed in the axial direction corresponding to each magnetic pole in the substantially cylindrical rotor core, and a permanent magnet is embedded in each slot. In the rotor of the type motor, the permanent magnet is magnetized in a magnetic orientation in which the magnetic flux of each part concentrates on one focal point, and the edge on the rotor core surface side of the permanent magnet is substantially directed to the focal point. The ineffective portion that does not contribute to the motor performance in the permanent magnet is eliminated, and the motor performance can be improved by effectively using the magnetic flux of the permanent magnet.
[Brief description of the drawings]
FIG. 1 is a longitudinal side view of a hermetic compressor according to an embodiment to which the present invention is applied.
2 is a perspective view of a stator of a motor of the hermetic compressor of FIG. 1. FIG.
FIG. 3 is a rear perspective view of the stator of FIG. 2;
4 is a plan view of a motor of the hermetic compressor of FIG. 1. FIG.
5 is a rear view of the motor shown in FIG. 4. FIG.
6 is a plan view of a stator core of the motor shown in FIG. 4. FIG.
7 is a side view of the stator core shown in FIG. 6. FIG.
FIG. 8 is a side view of the insulator of the stator in FIG. 2;
FIG. 9 is a side view of the insulator insulator of FIG. 2;
10 is a plan view of one insulator of FIG. 8. FIG.
11 is a front view of a support portion of the insulator shown in FIG. 10;
12 is a plan view of a support portion of the insulator shown in FIG.
13 is a cross-sectional view of a support portion of the insulator shown in FIG.
14 is a perspective view of a rotor core of a rotor of a motor of the hermetic compressor shown in FIG. 1. FIG.
15 is a plan view of the rotor core shown in FIG. 14. FIG.
16 is an enlarged plan view of a half of the rotor core of FIG.
17 is a diagram showing a magnetized state of the rotor of the motor of the hermetic compressor of FIG. 1;
18 is a view showing another embodiment of a rotor corresponding to FIG.
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 Compression element 5 Motor 7 Stator winding 8 Stator 9 Rotor 11 Rotating shaft 63 Rotor core 66 Slots 66A, 66B Edge MG Permanent magnet P2 Focus

Claims (2)

In a rotor of a permanent magnet type motor in which a slot is formed in an axial direction corresponding to each magnetic pole in a substantially cylindrical rotor core, 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 on 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 of a permanent magnet type motor. 2. The permanent magnet motor according to claim 1, wherein the slot and the inner peripheral edge of the rotor core of the permanent magnet inserted into the slot have an arcuate shape projecting toward the inner peripheral side of the rotor core. Rotor.

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