JPH09219941A - Rotating electric machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve the compact configuration and the light weight by performing the mutual welding of iron plates at the respectively independent welding points between two neighboring iron plates, and arranging the iron plates on the right and left sides zigzag for the laminating direction when the laminated iron plates are fixed as a unitary body and divided stator iron-core pieces are formed. SOLUTION: For laminated iron plates 31A, every two neighboring plates are welded by laser. The plates are fixed at welding points 33 formed in this way, and the laminated iron plates 31A are made to form a unitary body as a whole. In this way, an L-shaped iron-core piece 31 is constituted. At this time, the welding points 33 are arranged in the alternately deviated pattern on the right and left sides along the laminating direction shown by a broken line D of each iron plate 31A. That is to say, the iron plates are arranged zigzag for the broken line D. Thus, the thermal distortion caused by welding is prevented, the rod-shaped iron-core piece without the reduction in dimensional accuracy is obtained, the performance is improved and the compact configuration and the light weight are achieved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotating electric machine such as an induction motor or a synchronous machine, and more particularly to a rotating electric machine suitable for a relatively small-capacity general-purpose induction motor.

[0002]

2. Description of the Related Art A rotary electric machine having a relatively small capacity, such as a general-purpose induction motor, has a structure shown in FIG. In FIG. 5, reference numeral 1 denotes a housing, which is also called a frame or a frame, and is formed into a substantially cylindrical shape by casting an iron-based material such as cast iron, and constitutes a casing of the electric motor. Reference numeral 1a denotes a heat radiation fin, which is in the form of a strip extending in the axial direction, is integrally cast with the housing 1, and is radially formed on the outer periphery thereof.

2A and 2B are end brackets, which are also called bearing brackets, in which the bearings 4A and 4B are housed and are fitted to both ends of the housing 1 by spigot fitting.

Reference numeral 3 denotes a stator, and as shown in FIG. 6, a stator core 3A made of a laminated body of annular silicon steel plates (electromagnetic steel plates) having a plurality of slots 3C on the inner peripheral side is used. The stator winding 3B is wound inside the slot 3C of the iron core 3A.

A rotor 5 has a rotary shaft 6, and the rotary shaft 6 is rotatably held by bearings 4A and 4B of the end brackets 2A and 2B so that the rotor 3 can be rotated at a predetermined position in the stator 3. , Is configured to rotate at a position facing the stator 3.

In such a conventional motor, the stator 3 is inserted into the housing 1 in advance and attached to the inner peripheral wall thereof, and then the rotor 5 is inserted into the stator 3.
Then, the bearings 4A and 4B are fitted to the rotating shaft 6, and the end brackets 2A and 2B are fitted to both ends of the housing 1 by spigot fitting, respectively.
(Not shown), it is fixedly attached to the housing 1 and assembled.

The rotating shaft 6 has one end (the right side in the figure) inserted through the bearing 4B of the end bracket 2A and protrudes to the outside to form an output shaft, while the other end (the same, left side) is an end. An external cooling fan 9 (hereinafter, referred to as an external fan) is attached to a portion of the bracket 2A protruding from the bearing 4A.

Reference numeral 10 denotes an end cover, which forms a cover for covering the outer fan 9. And this end cover 10
The opening 10a for taking in outside air with the outside fan 9
(Hereinafter referred to as the ventilation inlet). The opposite side of the opening 10a is formed in an open cylindrical shape or an irregular cylindrical shape, so that a radial gap 10b is formed between the end bracket 2A and the outer diameter portion of the housing 1.
A ventilation outlet consisting of is formed.

Therefore, when the outer fan 9 is rotated by the rotor 5, outside air is sucked in from the ventilation inlet 10a of the end cover 10 and blown out from the gap 10b, whereby the end bracket 2A and the housing 1
And ventilating outside air to the outer surface of the end bracket 2B,
A cooling effect is obtained.

As described above, the rotor 5 is mounted in the housing 1 of the rotating shaft 6 at a position facing the stator 2. The rotor 5 has a secondary conductor bar (not shown) , An end ring 7, and an internal cooling fan 8 (hereinafter referred to as an inner fan) integrally formed with the end ring 7.

The inner fan 8 is composed of a plurality of blades protruding from both end surfaces of the end ring 7 in the axial direction to circulate air inside the electric motor so as to obtain a cooling effect. That is, the air flow generated by the inner fan 8 passes through the rotor 5, the end ring 7, the stator windings 3B, and both end faces of the stator core 3A while being cooled, and is relatively compared with the housing 1. When passing along the inner surfaces of the end brackets 2A and 2B having a low temperature rise, heat can be dissipated.

Incidentally, as a technique relating to this kind of prior art, for example, JP-A-61-251440 can be cited.

By the way, in such a rotary electric machine, miniaturization and weight reduction have always been a major proposition, but the miniaturization of the rotary electric machine tends to deteriorate the characteristics, and particularly the output and the stall torque (maximum torque). ) Tends to decrease. However, in order to prevent these decreases, if the number of windings of the stator coil (armature coil) is increased and the magnetic flux density is increased, there is a problem that iron loss increases and power factor and efficiency deteriorate. It was

In general, in order to make a rotary electric machine small,
It is effective to reduce the size of the stator, but in this case, in order to reduce the outer diameter of the stator and output the same torque, the magnetomotive force must be maintained at the same value. That is, it is necessary to configure the rotating electric machine without changing the magnetic load. In other words, it is important to keep the amount of magnetic flux per unit area of the stator (hereinafter referred to as magnetic flux density) constant without reducing the amount of magnetic flux generated in the stator.

However, in this state, the amount of magnetic flux remains the same as it was before miniaturization, and only the stator becomes smaller, resulting in an increase in magnetic flux density, which in turn causes magnetic flux saturation, resulting in deterioration of the characteristics of the rotating electric machine. Resulting in. Therefore,
Even if the stator becomes smaller, the magnetic flux density does not saturate,
In order to configure without changing the magnetic loading, it is necessary to secure the area of each magnetic path portion of the stator to be equal to that before the miniaturization. As a result, the slot area of the stator is reduced, so that the stator winding 3B is inserted in the slot.
Can no longer be stored.

In the prior art, this is the stator winding 3B.
Are inserted into the slots 3C one by one from the opening grooves, so that the stator windings 3 are not inserted in the slots 3C.
Since the arrangement of B becomes irregular, the storage volume of the coil is not comparable to the slot volume, and the volume ratio (hereinafter referred to as space factor) remains in the 60% range, and the coil storage is limited. Because there is.

Therefore, in order to improve the space factor, there has been conventionally known a split iron core type rotary electric machine in which a stator iron core is divided to improve the coil storability. This split-core-type rotating electric machine uses a stator iron core divided into a predetermined number and sequentially assembles these into a preformed stator winding to assemble the stator. Since it is not necessary to insert the coils one by one into the slots of the child iron core and perform winding, it is possible to fill the coils with no gaps in the slots, and as a result, a sufficient space factor improvement can be obtained. The size can be reduced.

By the way, in the method using such a split core type stator, it is difficult to assemble by simply stacking iron plates of a predetermined shape. Therefore, after stacking the iron plates, the whole is fixed and integrated, and the split fixing is performed. I set it as a child iron core piece and try to combine them.

In order to fix and integrate the laminated iron cores, in the prior art, after the iron cores are laminated, the outer peripheral surface of the laminated body is continuously welded.

[0020]

In the above-mentioned prior art, no consideration was given to maintaining the dimensional accuracy of the split stator core pieces, and there was the problem of performance degradation as described below.
That is, in the split core type stator, since a predetermined number of split stator core pieces are assembled by being joined in a ring shape, if the dimensional accuracy of each core piece is insufficient, a gap may occur in the joint portion, As a whole, a large reduction in dimensional accuracy is brought about.

However, in the prior art, since the laminated outer peripheral surfaces of the laminated cores are continuously welded and fixed to each other, distortion during welding occurs on the inner and outer peripheries of the iron cores, and the split stator core pieces after integration are formed. Bending or bending in the axial direction will be induced in the core, and as a result, when the core pieces are joined in an annular shape, a gap is created in the joint due to the distortion, and the dimensional accuracy of the stator core inner diameter is reduced. Then, there arises a problem that the exciting current of the rotating electric machine is increased, and vibration and noise are generated due to the imbalance of the air gap, so that the performance of the rotating electric machine is deteriorated.

It is an object of the present invention to provide a rotary electric machine in which the performance improvement and the size and weight reduction can be sufficiently obtained by using the split core type stator.

[0023]

SUMMARY OF THE INVENTION The above object is to provide a split iron core type rotating electric machine in which the formation of split stator core pieces by fixing and integrating the laminated iron plates is obtained by welding the iron plates to each other on the iron plate stacking surface. , The welding of the iron plates is formed by independent welding points between the two adjacent iron plates, and the welding points are arranged in a staggered pattern on the left and right with respect to the laminating direction of the laminated iron plates. To be achieved.

The thickness of the iron plate that constitutes the stator of the rotating electric machine is generally about 0.5 mm, which is quite thin. After this iron plate is punched and formed into a predetermined shape, it is laminated to form a stator core. . The strain generated in the laminated iron core is due to the influence of heat during welding,
The welding method should be devised so that the influence of this heat is minimized.

Therefore, if the welding points are arranged in a zigzag manner in the laminating direction, the welding points do not overlap on the same straight line in the laminating direction. Can be suppressed.

Further, at this time, by controlling the welding output, the laminated iron plates can be firmly joined to each other with an appropriate welding strength, and thus a solid split stator core piece free from welding distortion can be obtained. it can.

[0027]

BEST MODE FOR CARRYING OUT THE INVENTION A rotating electric machine according to the present invention will be described in detail below with reference to embodiments. One embodiment of the present invention is an induction motor, but the overall configuration is the same as the conventional induction motor described in FIG. 5, and different points are as follows.
Since only the stator core 3A has a split core shape, the configuration of the stator core 3A will be mainly described below.

FIG. 2 shows a stator core 3A according to an embodiment of the present invention. As shown, the stator core 3A is composed of an L-shaped core piece 31 and a rod-shaped core piece 32. A plurality of L-shaped iron core pieces 31 are sequentially arranged in an annular shape and combined after being formed in a shape divided into types, while a rod-shaped iron core piece 32 is formed into a shape of the L-shaped iron core piece 31. The stator core 3A is configured by inserting the slots into the notches on the inner circumference of the slot space substantially outward from the central axis O of the stator core 3A and combining them.

First, as shown in FIG. 3 (a), the L-shaped core piece 31 has a back portion 31a having a proper width in the circumferential direction and one end surface portion of the back portion 31a, that is, the right end surface portion in the figure. The tooth portion 31b protruding in the central axis O direction of the stator core 3A, the notch portion 31c forming the space portion for the slot provided on the left side of the tooth portion 31b, and the space portion cutting portion The notch 31c is formed in a shape having a toothed portion 31b and a notched portion 31d having substantially the same width as the toothed portion 31b on the left side thereof. Is not parallel to the straight line indicated by the chain line extending toward the central axis O of, but is inclined by a predetermined angle θ.

Next, as shown in FIG. 3 (b), the rod-shaped core piece 32 has a root portion 32a at one end and a tooth portion 32b at the other end, and the tip end of the tooth portion 32b. The rod-shaped iron core is formed in a rod shape having a tongue piece 32c that forms a slot opening, and when the root portion 32a is radially inserted into the notch 31d in the inner periphery of the slot space portion of the L-shaped iron core piece 31. A slot 3C for housing the stator coil is defined between the tooth portion 32b of the piece 32 and the tooth portion 31b of the L-shaped iron core piece 31.

Therefore, the back portion 31a of each L-shaped iron core piece 31
The dimension in the circumferential direction is such that when the rod-shaped core piece 32 is inserted and engaged, the tooth portion 31b adjacent thereto forms a space portion of the slot 3C having a predetermined dimension. .

The L-shaped iron core piece 31 and the rod-shaped iron core piece 32 are each made of an iron plate which is punched out from a silicon steel plate into a plane shape as shown in FIG. It is welded and fixed, and is integrally formed, thereby forming a split stator core piece.

FIG. 1 shows an L-shaped iron core piece 31 according to an embodiment of the present invention. In the drawing, 31A is a laminated iron plate and 33 is a welding point. And this FIG.
As is apparent from the above, in this embodiment, the laminated iron plates 31A are sequentially laser-welded by two adjacent sheets, and the welding points 33 formed thereby are fixed to each other as shown in the figure. As a result, the laminated iron plates 31A
The whole is integrated and the L-shaped core piece 31 is configured.

At this time, however, these welding points 33
Is not arranged on the same straight line along the stacking direction indicated by the broken line D of each iron plate 31A as shown in the figure, but is arranged alternately left and right with respect to the stacking direction D, that is,
They are arranged in a zigzag pattern in the stacking direction D.

Although not shown, the same applies to the rod-shaped core piece 32, and the laminated iron plates constituting the bar-shaped core piece 32 are sequentially laser-welded to each other by two adjacent sheets. To be integrated with each other. At this time, the welding points are also arranged in a zigzag pattern in the stacking direction.

Therefore, according to this embodiment, since the welding spots are not formed on the same straight line in the stacking direction, heat concentration due to welding does not occur, and as a result, distortion due to heat is minimized. A solid split stator core piece that is suppressed and does not reduce dimensional accuracy due to welding distortion, that is,
The L-shaped core piece 31 and the rod-shaped core piece 32 can be easily obtained.

As a result, the stator core 3A is formed by using the L-shaped core piece 31 and the bar-shaped core piece 32, and the induction motor shown in FIG. The performance improvement and the reduction in size and weight can be sufficiently obtained by using.

Further, at this time, in this embodiment, by controlling the welding output by the laser, the penetration depth of the welding point 33 from the outer peripheral surface of the laminated iron plates is determined by the thickness of the laminated iron plates. The heat generation is suppressed to 2 times or less, and as a result, heat generation due to welding can be minimized and distortion generation can be further suppressed while maintaining the required appropriate welding strength.

By the way, in the above-described embodiment, as is clear from FIG. 1, the welding points 33 are located on the left and right sides in the welding direction D.
The rows are arranged in a staggered manner, but the arrangement may be more than two rows. FIG. 4 shows an example of an embodiment of the present invention in a staggered arrangement of three rows, and this embodiment also provides
Similar to the embodiment of FIG. 1, the performance improvement and the reduction in size and weight can be sufficiently obtained by using the split core type stator.

[0040]

According to the present invention, a solid split stator core piece with good dimensional accuracy can be obtained, so that the advantages of using the split iron core type stator can be fully utilized. The effect can be obtained.

1. It is possible to provide a rigid stator with high dimensional accuracy.

2. By using the above-mentioned stator, it is possible to provide a rotating electric machine that is smaller and lighter than conventional ones.

3. It is possible to provide a low-vibration, low-noise rotating electric machine that is small in size and light in weight, has no reduction in efficiency or power factor, and has good performance.

[Brief description of drawings]

FIG. 1 is a partially enlarged perspective view of a split stator core piece in an embodiment example in which the present invention is applied to an induction motor.

FIG. 2 is a front view of an exploded iron core type stator core according to the embodiment of the present invention.

FIG. 3 is an exploded view of a disassembled iron core type stator core according to an embodiment of the present invention.

FIG. 4 is a partially enlarged perspective view of a split stator core piece in another embodiment example in which the present invention is applied to an induction motor.

FIG. 5 is an explanatory diagram of a conventional example of an induction motor shown as an example of a rotating electric machine.

FIG. 6 is a plan view of a stator core in a conventional example of a rotating electric machine.

[Explanation of symbols]

 1 Housing 3 Stator 3A Stator Iron Core 3B Stator Coil 3C Slot 31 L-shaped Core Piece 31A Laminated Iron Plate 31a Back 31b Teeth 31c Slot Notch 31d Notch 31e, 31f Circumferential End Face 32 Rod-shaped core piece 32a Back part 32b Tooth part 32c Tongue piece 33 Welding point

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Kaoru Ogawa 7-1, 1-1 Higashi Narashino, Narashino City, Chiba Prefecture Hitachi Industrial Co., Ltd. Industrial Equipment Division (72) Inventor Tsuneo Sekine 4-6 Kanda Surugadai, Chiyoda-ku, Tokyo Address Hitachi, Ltd. (72) Inventor Yukio Endo 4-6 Kanda Surugadai, Chiyoda-ku, Tokyo Inside Hitachi, Ltd. (72) Inventor Matsuri 4-6 Kanda Surugadai, Chiyoda-ku, Tokyo Hitachi Ltd. (72) Inventor Izumi Shimizu 4-6 Kanda Surugadai, Chiyoda-ku, Tokyo Hitachi, Ltd. (72) Inventor Takahiro Takeda 7-1 Higashi Narashino, Narashino City, Chiba Hitachi Industrial Co., Ltd.

Claims (2)

[Claims] 1. A split-core-type rotary electric machine in which the formation of split stator core pieces by fixing and integrating laminated iron plates is obtained by welding the iron plates to each other on the iron-plate stacking surface, wherein the welding of the iron plates to each other comprises: A rotary electric machine, wherein the two adjacent iron plates are formed by independent welding points, and the welding points are arranged in a zigzag pattern on the left and right with respect to the laminating direction of the laminated iron plates. 2. The invention according to claim 1, wherein the welding point is formed by laser welding, and the penetration depth of the welding point is 2 times the plate thickness of the laminated iron plates.
A rotating electrical machine characterized by being reduced to less than double.