JP3456144B2 - Rotating electric machine - Google Patents

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, and is suitable for, for example, an AC generator mounted on a passenger car, a truck or the like, or a ship, and rotationally driven by an internal combustion engine.

[0002]

2. Description of the Related Art Quieting of vehicles is advancing and the need for noise reduction of auxiliary machinery is increasing. For example, in a vehicle AC generator that is almost always operating during operation, there is a strong need for low magnetic noise, but it is difficult to solve because it is inconsistent with the tendency of vibration increase due to thinning and lightening for vehicles. That is, it is required to provide a product with low magnetic noise without increasing the mass.

In general, the magnetic sound is radiated as a compression wave of air by magnetically pulsating the air gaps of the stator and the rotor facing each other by vibrating and deforming the stator core and windings, and up to the frame supporting it. It is well known that this is caused by oscillating deformation and radiating as a compressional wave of air. Therefore, it is also well known that the noise level is lowered if the rigidity is improved in preparation for the increase in the mass of the stator which is the generation source.

However, since a light weight is firstly required for vehicles, it is necessary to achieve this without increasing the mass. Then, there is Japanese Utility Model Laid-Open No. 5-50969 as a method of reducing the magnetic noise while preventing an increase in mass. This publication discloses a structure in which the rigidity of an aluminum frame supporting the stator is improved to suppress the magnetic vibration of the stator, which is one of the magnetic sound sources. However, in the above-mentioned configuration, although the rigidity is improved by aluminum which is a light metal, the increase in mass can be suppressed, but the rigidity of the stator which is the vibration source is not directly increased, and the effect is limited.

On the other hand, Japanese Unexamined Patent Publication No. 62-225140 discloses a structure in which magnetic resistance unevenness of a stator core is intentionally formed to disperse vibration frequency components during rotation to reduce magnetic noise. Has been done. In this configuration, although there is no mass increase at all, as described in the above publication,
Since it does not reduce the vibration amplitude, even if the main body itself makes a low magnetic noise when it is mounted on a vehicle, it will excite resonance of surrounding parts, and it will not be possible to achieve a low magnetic noise as a whole. there were.

As described above, the magnetic noise cannot be reliably reduced by restraining the already generated stator vibration with the rigid member or simply changing the timbre. Therefore, it is desired to suppress the vibration before the magnetic vibration occurs in the stator. The magnetic vibration in this stator has a small exciting force, but this may cause the stator core to resonate at its natural frequency and appear significantly. further,
In some cases, vibration from the stator core may be propagated and greatly appear in the extending portion of the stator winding extending from the slot.

An object of the present invention is to provide a rotating electric machine which suppresses the vibration of the stator and has low noise. Another object of the present invention is to suppress the resonance of the stator. Still another object of the present invention is to suppress the vibration of the stator with a relatively simple structure while adopting a structure capable of improving the space factor of the winding in the slot.

[0008]

According to the invention as set forth in claim 1, a rotor fixed to a rotary shaft and having NS magnetic poles alternately arranged at substantially equal pitches in the circumferential direction of rotation, and an outer periphery of the rotor. the rotating electric machine having arranged to face the stator accommodating fixing the stator winding slots of the stator core, the solid
The stator winding extends from both sides of the stator core in the axial direction.
Then , along with the axial direction of the rotating shaft by heat softening treatment
It is characterized in that an extension portion whose hardness gradually increases from the tip to the root is provided .

By changing the hardness of the winding along the axial direction of the rotary shaft in this manner, the hardness of the winding is different at the portions separated along the axial direction. Therefore, the winding itself has a rigidity distribution capable of suppressing the vibration, and vibration of the stator is suppressed. In particular, the difference in hardness of the winding leads to the difference in rigidity with respect to vibration, which suppresses resonance.

The rigidity of the assembly of the iron core and the windings may be different in the front and rear directions in the axial direction by changing the hardness of the windings in the axial direction. In this case, even if a symmetrical vibration excitation force is generated in the front and rear in the axial direction due to the rotation of the magnetic poles facing the stator, it is difficult to transfer the vibration energy such as a tuning fork in the front and rear in the axial direction of the stator. As a result, resonance before and after the axial direction of the stator can be suppressed.

By thus changing the hardness of the extending portion of the winding in the axial direction, the hardness can be suppressed .

Since the hardness changing process may be performed from the end portion side of the extending portion, the hardness changing process can be facilitated.

[0013]

[0014]

[0015]

According to the invention of claim 2 , claim 1
In the above, the winding is uniformly work-hardened by deforming its cross-sectional shape.
Therefore, the hardness of the winding can be increased by a simple process of changing the cross-sectional shape. According to the invention described in claim 3, in claim 1 or 2, wherein the winding is characterized by comprising a continuous line that is inserted into the slot.

According to such a structure, while using a continuous wire which has a relatively simple structure and can be manufactured at low cost as the winding wire, by deforming the cross-sectional shape, the space factor in the slot is improved. While obtaining, it is possible to suppress the vibration by utilizing the work hardening accompanying the deformation of the cross-sectional shape. The deformation of the cross-sectional shape can be performed uniformly in the length direction of the continuous line, and the desired hardness can be obtained uniformly.

According to the invention described in claim 3, claim 1
1 to 3, the winding wire is provided with a plurality of fragment conductors joined to each other at an end portion of an extension portion extending from the slot.

[0019]

For example, by adopting a joining technique involving heating, the fragment conductors can be heated at the ends of a plurality of the fragment conductors at the same time as joining, and at the same time the electrical connection is obtained and the hardness is lowered by the heating. Processing can be added. In addition, you may confirm that the heat-softening process was performed by the presence of the joining part formed with joining of several fragment conductors. By confirming the existence of the joint portion, it is possible to easily and surely confirm visually. Further, the degree of heating and softening may be grasped by the shape such as the melting condition of the joint portion. Therefore, manufacturing control becomes easy.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION [First Embodiment] A 100A class vehicle alternator according to a first embodiment of the present invention will be described with reference to the drawings. In FIG. 1, an automotive alternator 1 has a stator 2 that serves as an armature and a rotor 3 that serves as a field magnet. Then, the stator 2 and the rotor 3
And are supported by the frame 4. Further, the frame 4 is provided with a regulator and a rectifier (not shown) which are connected to the stator 2 and convert AC power into DC.

In the rotor 3, a field iron core 6 having a total of 12 claw-shaped magnetic poles 5 is knurled to a shaft 7. The left end of the shaft 7 in FIG. 1 is a power input end and a pulley is fixed. A field winding 8 is wound around the central boss portion of the field iron core 6. The field winding 8 is connected to a regulator (not shown) via a slip ring 9 and a brush 10. The claw-shaped magnetic poles 5 of the rotor 3 alternately provide north poles and south poles.

The stator 2 has a diameter of about 12 which is obtained by laminating electromagnetic steel plates having a thickness of about 0.5 mm in the axial direction of the rotating shaft by about 30 mm.
It has a stator core 201 of 0 mm, and this stator core 20
1 has 36 slots 202 on its inner circumference. Each of the slots 202 is provided with a copper wire 20 which is a continuous wire that provides a multi-phase stator winding. As shown in FIG. 2, the copper wire 20 has a portion extending from the inside of one slot 202 along the axial direction to the outside.
It is provided so as to be bent in the direction opposite to the extending direction and to be inserted into another slot 202 again. In FIG.
An insulator 204, which is an electrically insulating material, is interposed between the copper wire 20 and the inner wall of the slot 202.
The copper wire 20 is pressed and inserted into the slot 202, and the insulator 204 is sandwiched between the copper wire 20 and the slot 2 of the iron core 201.
It is fixed in 02. Further, the copper wire 20 is made of the fixing material 207.
Thus, it is impregnated and fixed in the slot 202 of the iron core 201 together with the insulator 204. The copper wire 20 has a substantially rectangular cross-section, and the outer periphery thereof is covered with an organic insulating film.

Here, the copper wire 20 providing the winding of the present embodiment is formed by flattening almost all of the electric soft copper having a cross-sectional area of about 2 mm ² into a rectangular cross section. Work-hardened one is used. The winding wire extends from both axial end surfaces of the iron core 201 as extension portions 205 and 206. These parts are also called coil ends. The extending portions 205 and 206 are annularly arranged on both end surfaces of the iron core 201.

Then, the extension portion 205 on the pulley side is heat-softened. This heat-softening treatment is performed on the axial end portion of the extension portion 205 of the copper wire 20 partially on the coating or after breaking the coating, whereby the heating-treated portion is partially removed as shown in FIG. Is generated. FIG. 4 shows an example of the hardness distribution of the extended portion. The work hardening remaining on the axial end of the extending portion 205 is removed by the heat treatment. Therefore, the hardness of the tip of the extended portion 205 is the lowest compared to before the heating when the entire copper wire is hardened. The influence of the heat treatment becomes smaller as it approaches the slot along the axial direction, and the hardness increases before the heat treatment. Therefore, the extending portion 205 from the pulley-side slot of the copper wire 20 is softer as it is closer to the end side, that is, the heat treatment portion, and is harder as it is closer to the slot. In addition, it can be said that the extension of the copper wire 20 from the slot is such that the pulley-side extension 205 is soft and the non-pulley-side extension 206 is hard.

As described above, the stator 2 has low vibration rigidity on the pulley side and high vibration rigidity on the side opposite to the pulley, and the vibration phases before and after that are different. Therefore, the effect of restraining vibration displacement mutually, that is, damping The effect can be obtained. Therefore, magnetic noise can be reduced. In addition, since the hardness of the extension of the copper wire 20 from the slot is changed, the propagation of vibration from the stator core 201 to the extension of the copper wire 20 can be attenuated. Therefore, the magnetic noise due to the vibration of the extension of the copper wire 20 from the slot 202 can be reduced.

Further, in the above structure, since the copper wire 20 is preformed and heat-softened, the degree of change in hardness can be made larger than in the case of using a normal round wire. Therefore, a higher vibration damping effect can be obtained, and the magnetic noise can be further reduced. Further, since the work hardening treatment and the heat softening treatment for giving the hardness change as described above are performed, it is possible to perform a special and expensive treatment such as changing the material composition of the winding along the axial direction,
The hardness can be changed very easily. Furthermore, since the heating and softening may be performed from the end side of the extending portion 205, the processing is easy.

Since the copper wire 20 can be freely subjected to work hardening treatment, the copper wire 20 can be uniformly made to have a desired hardness. In addition, the copper wire 20 may be purchased after being preliminarily subjected to the rectangular molding process and used. However, even in this case, it is important that the copper wire 20 is not softened by heating by annealing and has hardness by work hardening.

The effect of the above configuration is shown in FIG.
When the stator 2 of the 100 A class generator of the first embodiment and the stator of the conventional generator are hit by the same vibrator with the same exciting force, the amplitude ratio of the resonance vibration thereof is confirmed. It is possible to obtain a large vibration damping effect of being reduced to 1/6 or less. Further, FIG. 6 shows characteristics of magnetic noise with respect to the rotation speed of the generator when the stator of this embodiment is mounted on the generator. As is clear from this figure, it can be confirmed that the magnetic noise generated in the generator of this embodiment is reduced as compared with the conventional one. It should be noted that in the low rotation range per 1500 rpm (generally, the pulley ratio of the generator is about 2.5, the range is about 1000 to 4000 rpm for the generator) from the idle rotation of the engine, which is considered to be a magnetic noise, over the entire range. A remarkable magnetic noise reduction effect of about 5 to 7 dB was obtained. Although not shown in the figure, the same remarkable effect was obtained with generators of other output classes.

[Second Embodiment] Next, a second embodiment will be described with reference to FIGS. In the present embodiment, the stator winding is provided by using a plurality of fragment conductors 203 shown in FIG. 9 and joining them together. The fragment conductor 203 is formed by molding a copper wire having a circular cross section into a rectangular cross section, and by this molding, the entire fragment conductor 203 is work-hardened. Moreover, the molded piece conductor 203
The cross sectional shape of is a shape along the slot cross section. By inserting the conductor 203 into the slot as described later to form a winding, the space factor of the winding in the slot is improved.

The fragment conductor 203 has two straight portions 203A.
And a U-shaped portion 203B connecting them. And
As shown in FIGS. 7 and 8, the fragment conductor 203 has a straight line portion 20.
3A are aligned in the radial direction in the slot 202 and inserted into the slot 202. At this time, the iron core 20
The U-shaped portions 203B are arranged at one end of the one. on the other hand,
Straight part 2 extending outward from the other end of the iron core 201
By bending the tip end of 03A and joining the end to the end of another fragment conductor 203 as shown in FIG. 7, a stator winding can be formed as a whole.

In FIG. 7, among the plurality of fragment conductors 203, the conductor 2031 and the conductor 2032 are welded at the melting point 2051. By this welding, heat softening treatment is performed and electrical connection is made. Similarly, melting point 2052,
At 2053, ..., all the fragment conductors 203 are welded at their end portions, heat-softened, and electrically connected. As described above, since the heating and the softening treatment are performed at the same time as the electrical connection by the welding, there is an effect that it is simple and the number of steps is small.

As shown in FIG. 7, one straight portion 203A of a fragment conductor 203 extends from the outer layer of the slot 202 in the circumferential direction. The other straight portion 203A of the fragment conductor 203 extends from the inner layer of the slot 202 in the opposite circumferential direction. And the straight part 2 of the outer layer
The end portion of 03A is the linear portion 2 of the inner layer of the other fragment conductor 203.
It is joined to the end of 03A. As a result, the ends of the linear portions 203A of each of the plurality of fragment conductors 203 are joined to each other in the circumferentially extending directions opposite to each other. Therefore, all the extending portions of the winding are spaced apart from each other in the circumferential direction and the radial direction.

On the other hand, as shown in FIG. 8, a U-shaped portion 203B
Also extends from the slot 202 and another slot 2
02 has been inserted. Therefore, all the U-shaped portions 203B as the extending portions of the winding are separated from each other. In the above-described embodiment, since the fragment conductor 203 is welded and connected only at the end of the linear portion 203A, the fragment conductor 203 is softened by the heat for welding and the hardness is changed. Exhibits high vibration damping effect.

Further, as described above, the extension portion softened by welding is arranged at one end of the stator core 201, and the extension portion in which work hardening is maintained is arranged at the other end. Therefore, the hardness is changed in the axial direction of the iron core 201, and a high vibration damping effect is obtained. Moreover, as shown in FIG. 9, the fragment conductor 20 that is work-hardened by molding is used.
In the U-shaped portion 203B of No. 3, work hardening is further applied by the bending work for forming the U-shape. Therefore, the hardness change can be set larger. Therefore, the vibration can be further damped.

Further, according to the above embodiment, the iron core 201
When the coil and the winding are regarded as a cylindrical shape as a whole, so to speak, portions having substantially the same hardness are arranged and arranged in an annular shape. Therefore, the hardness distribution can be obtained in the axial direction as a whole of the stator 2, and a high vibration damping effect can be obtained. In addition, as shown in FIG.
By visually observing 1, 2052, 2053, ..., it is possible to easily confirm whether the heating and softening and the electrical connection have been reliably performed, and moreover, the degree thereof can be grasped by the melting condition. Therefore, manufacturing control becomes easy.

[Other Embodiments] Next, other embodiments will be described. In the first embodiment described above,
In the copper wire 20 provided as the winding, the end on the pulley side is heat-treated, but the opposite end may be used. In addition, in the first and second embodiments, damage to the film coated on the copper wire 20 or the fragment conductor 203 is avoided by heating one end of the stator at a relatively low temperature and forcibly cooling the other. be able to.

In the first and second embodiments, only one end of the extending portion extending from the stator core 201 of the winding is softened, but both ends of the extending portion are softened. May be. For example, the linear piece conductor 213 shown in FIG. 10 may be used. In this conductor 213, after inserting the straight portion 213A into the slot from one side in the axial direction, the fragment conductors 213 are bent at the other side in the axial direction at a predetermined pitch, and the two fragment conductors 213 are electrically connected by welding or the like accompanied by heating. By doing so, the winding is formed. As a result, both portions of the fragment conductor 213 extending from the slot are hard on the side close to the slot and soft on the axial end side. Therefore, vibration propagation from the stator core to the tip of the conductor can be damped. Therefore, it is possible to reduce the magnetic noise due to the vibration of the extending portion extending from the slot of the winding.

The heat softening treatment may be performed so that the hardness distribution is different from that shown in FIG. For example, a
The hardness of the point may be as low as that of FIG. 4, and the softening treatment may be performed so that the hardness before the heating is maintained at a steep hardness distribution such that the hardness before the heating is maintained near the point b or the point c.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view of a vehicle AC generator that is a first embodiment to which the present invention is applied.

FIG. 2 is a partial perspective view of a stator showing an extending portion of a winding.

3 is a cross-sectional view showing a cross section perpendicular to the axial direction of the stator shown in FIG.

FIG. 4 is a graph showing the hardness distribution in the axial direction of the winding extension portion of the first embodiment.

FIG. 5 is a graph showing the difference between the resonance characteristic of the conventional stator and the resonance characteristic of the stator of the first embodiment.

FIG. 6 is a graph showing magnetic sound characteristics of the stator of the first embodiment in comparison with that of a conventional stator.

FIG. 7 is a perspective view of one side surface in the axial direction of the stator according to the second embodiment.

FIG. 8 is a perspective view of the other axial side surface of the stator according to the second embodiment.

FIG. 9 is a perspective view of a fragment conductor of a stator according to a second embodiment.

FIG. 10 is a perspective view of a fragment conductor of a stator according to another embodiment.

[Explanation of symbols]

1 Vehicle AC generator 2 stator 3 rotor 4 frames 5 claw-shaped magnetic poles 6 field iron core 8 field winding 20 copper wire 201 Stator core 202 slots 203 fragment conductor 204 insulator 205 extension 206 Extension part 213 fragment conductor

Continuation of front page (56) Reference JP-A-8-205441 (JP, A) JP-A-6-209547 (JP, A) JP-A-6-284651 (JP, A) JP-A-8-317582 (JP , A) JP 7-298528 (JP, A) JP 6-209546 (JP, A) JP 5-304748 (JP, A) JP 5-115158 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) H02K 3/20

Claims (4)

(57) [Claims] 1. A rotor fixed to a rotary shaft, in which NS magnetic poles are alternately arranged at substantially equal pitches in the circumferential direction of rotation, and the rotor.
Extending in the rotating electrical machine, the stator winding, the axial surfaces of said stator core having opposed arranged stator accommodating fixing the stator winding slots of the stator core to the outer periphery of the
An extension part where the hardness gradually increases from the tip to the root part along the axial direction of the rotating shaft due to the extrusion and heat softening treatment.
A rotating electric machine characterized by being provided . 2. The stator winding according to claim 1 , wherein the stator winding is uniformly work-hardened by preliminarily deforming its cross-sectional shape and inserted into the slot.
Rotating electric machine, characterized in that there. 3. The method of claim 1 or 2, wherein the stator winding, the rotary electric machine characterized by comprising a continuous line that is inserted into the slot. 4. The method of claim 1 or 2, wherein the stator winding comprises a plurality of pieces conductors to be inserted into said slot, child weld the ends of the fragments conductor
The rotating electric machine is characterized in that the stator winding is formed by and the heating and softening treatment is performed by this welding .