JPH0746795A - Rotory electric equipment - Google Patents

Abstract

PURPOSE:To provide a rotary electric equipment which has a coil end of its stator coil cooled well without decreasing an amount of cooled air or increasing the size. CONSTITUTION:Cooled air coming out of a fan 6 passes through a blow-out path P formed between an inner end face of a housing 12 and a coil end 34R of a stator coil and then is blown out through a cooling window 'w' which is made in an outer wall of the housing 12. An end face of the coil end 34R which faces the blow-out path P has a staged part (a recess) 340 in the axis direction. Due to this structure, a contact area (radiation area) of the stator coil which is brought into contact with cooled air can be increased, with the reduction in a cross-sectional area of the blow-out path P being minimized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cooling structure for a rotating electric machine.

[0002]

2. Description of the Related Art Japanese Patent Application Laid-Open No. 4-249 filed by the present applicant
JP-A-39 discloses a cooling structure in which centrifugal fans are provided at both ends of a rotor core, and cooling air blown from the centrifugal fans flows into a cooling window opened in a peripheral wall of a housing while cooling the coil ends of the stator coil. By lowering the temperature of the coil end, the air passage for cooling air is installed in parallel with the blowing direction of the centrifugal fan.

[0003]

However, as in the prior art described above, it is necessary to form a large number of the above-mentioned air ducts in the coil end of the stator coil in the direction parallel to the blow-out direction of the centrifugal fan. Line work becomes complicated. In addition, providing the above-mentioned many air ducts at the coil ends means that the windings of each coil extend so as to surround these air ducts, which increases the wire length of the stator coil and the copper loss of the stator coil. .

Further, since the axial dimension of the coil end of the stator coil is increased, there is a disadvantage that the flow passage cross-sectional area of the blowing flow passage between the end face of the coil end and the inner end face of the housing is reduced, and the cooling air flow rate is increased. There is a concern that the temperature may decrease and cooling in other parts may deteriorate. Of course, although there is an increase in the cooling air volume through the air passage, the fluid pressure loss of the air passage having a complicated shape inside the coil end is large, and it is not possible to compensate for the decrease in the cooling air volume of the blowout passage. It is necessary to increase the housing size in order to secure the required cooling air volume.

The present invention has been made in view of the above problems, and an object thereof is to provide a rotary electric machine capable of excellently cooling the coil end of a stator coil while avoiding a decrease in cooling air volume and an increase in body size. I am trying.

[0006]

A rotating electric machine according to the present invention includes a housing having a cooling window opened in a peripheral wall, a stator coil wound around a stator core fixed to the housing, and a stator core. A rotor core that is rotatably held in the housing, and a fan that is located on the inner peripheral side of the cooling window and is fixed to the end surface of the rotor core and blows out at least part of the cooling air in the centrifugal direction. In at least a part of the rotary electric machine that blows out from the fan, passes through the blowout flow passage between the inner end surface of the housing and the coil end of the stator coil, and flows into the cooling window, the rotary electric machine facing the blowout flow passage The end surface of the coil end of the stator coil has a step in the axial direction.

[0007]

The cooling air discharged from the fan (at least a part of the cooling air) passes through the blow-out passage between the inner end surface of the housing and the coil end of the stator coil, and from the cooling window opened in the peripheral wall of the housing. Blown out. The end surface of the coil end of the stator coil facing the blowout flow path is
It has a step in the axial direction.

With this arrangement, the contact area (heat dissipation area) of the stator coil which comes into contact with the cooling air can be increased while minimizing the reduction of the cross-sectional area of the blow-out passage. Also,
It is possible to avoid an increase in the wire length of the stator coil and an increase in resistance loss as compared with the above-described conventional technique, and it is possible to realize the securing of the cooling air volume without increasing the size.

Further, unlike the above-mentioned prior art, it is not necessary to form a complicated-shaped air passage at the coil end, so that the stator coil forming process becomes relatively easy.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A vehicle alternator according to an embodiment of the present invention will be described with reference to FIG. First, the basic configuration of this generator will be outlined. A frame (housing in the present invention) 1 composed of a front frame 11 and a rear frame 12 is fastened by a plurality of fastening bolts 13. The frame 1 rotatably supports a rotary shaft 2, and the rotary shaft 2 is a Lundell type. The field core (rotor core in the present invention) 31 is fixed, and the field core 31
A field coil (rotor coil) 32 is wound around. The field core 31 and the field coil 32 form a rotor. An armature core (stator core in the present invention) 33 is fixed to the inner peripheral surface of the frame 1 so as to surround the field core 31.
An armature coil (stator coil in the present invention) 34 is wound around the armature core 33. The armature core 33 and the armature coil 34 form a stator.

A cover 4 made of aluminum, resin or the like is fixed so as to surround the rear end surface of the rear frame 12, and an electric component chamber S is formed between the rear frame 12 and the cover 4. A rectifying device 41, a brush 42, and a regulator 43 are housed in the electric component room S. When the engine (not shown) belt-drives the rotary shaft 2 through the pulley 21 and energizes the field coil 32 to excite it, the three-phase AC voltage generated in the armature coil 34 is transferred to all three-phases by the rectifier. Wave rectified and output.

A mixed flow fan 5 and a centrifugal fan 6 are fixed to the rotary shaft 2 with a field iron core 31 interposed therebetween. The centrifugal fan 6 constitutes the fan referred to in the present invention. On the peripheral wall of the front frame 11, a large number of cooling windows w ′ are opened so as to surround the mixed flow fan 5 in a line in the circumferential direction, and on the peripheral wall of the rear frame 12, a large number of cooling windows are surrounded by the centrifugal fan 6. The openings w are arranged in a line in the circumferential direction.

The centrifugal component 100 of the wind generated by the mixed flow fan 5 is blown out from the cooling window w'while cooling the coil end 34F on the front side of the stator coil 34, and the axial flow component 101 is each pole of the rotor core 31. To the rear end surface of the rotor core 31 and is deflected in the centrifugal direction by the disk portion of the centrifugal fan 6 and the like, and the coil end 34R on the rear side of the stator coil 34.
Through or through a blow-out passage P described later along the inner peripheral surface and the end surface of the coil end 34R to cool the coil end 34R and be blown out from the cooling window w.

Most of the wind 102 generated by the centrifugal fan 6 is the rear coil end 3 of the stator coil 34.
It is blown out in the centrifugal direction from the cooling window w through the blowout flow path P between the end surface of 4R and the inner end surface of the rear frame 12. The characteristic part of this embodiment will be described below. Figure 1
As shown in, front frame 11 and rear frame 1
2 is fastened by a plurality of (four in this case) fastening bolts 13, and the bottom surface of the nut 14 screwed to the fastening bolts 13 is in contact with the seat surface 12x of the rear frame 12 and the seat surface 1
Press 2x to the front side.

The seat surface 12x is formed in the vicinity of the cooling window w in order to reduce the outer diameter and axial length (hereinafter, referred to as axial length) of the rear frame 12. Therefore, the through hole 12e for fitting the fastening bolt 13 through the rear frame 12 is formed.
The surrounding cylindrical portion has an overhanging portion 12b (see FIG. 3) that overhangs the above-mentioned blowout flow path P, and in the end, the overhanging portion 12b is formed in the blowout flow path P 90 degrees apart in the circumferential direction. become.

In this embodiment, these overhanging portions 12b are
In consideration of the existence of the overhanging portion 12b, as shown in FIG.
In the angular position where is present, the axial length a from the end surface of the rotor core 31 to the end surface of the coil end 34R is conventionally (see FIG. 4).
The axial length b from the end surface of the stator core 33 to the end surface of the coil end 34R is set longer than the axial length a at the angular position where the overhanging portion 12b does not exist.

More specifically, as shown in FIG.
The coil end 34R has a groove portion 340 that extends in the radial direction at an angular position where the protruding portion 12b exists. The circumferential dimension of the groove portion 340 is D and the axial dimension is L. By doing so, the following effects can be obtained. First, the coil end 34R is better than the conventional coil end (see FIG. 4).
Since it can be projected in the axial direction, the coil end 34R
The cooling effect of is improved. Further, since the end surface of the coil end 34R is uneven, the surface area thereof is increased and the cooling effect is improved.

Secondly, nevertheless, since the coil end 34R does not project to the rear side in the axial direction at the angular position where the overhanging portion 12b exists, the coil end 34R does not project.
Does not come into contact with the overhanging portion 12b. Thirdly, the cooling air 102 blown out in the centrifugal direction from the centrifugal fan 6 is blown out in the centrifugal direction and flows into the blowout flow passage P, but the blowout flow passage P is The required width can be provided in the axial direction over the entire circumference, and the cooling air 102 can be blown out smoothly.

In order to provide the above-mentioned unevenness on the coil end 34R, a stator coil provided with such unevenness in advance is fitted into each slot of the stator core 13, or a stator coil not subjected to unevenness treatment is used for the stator core 1.
The coil end 34R may be forcibly deformed after the coil end 34R is fitted into each of the slots. (Modification) In the above-described embodiment, the surface area of the coil end 34R can be increased while ensuring the blowout flow path P, and the temperature of the coil end 34R can be reduced.

However, if the axial dimension fb between the projecting end surface (convex end surface) of the coil end 34R and the inner end surface of the rear frame 12 is reduced too much, no matter how much the blowing cross-sectional area of the groove 340 increases, Fluid resistance will increase.
This is because the cooling air 102 blown out from the centrifugal fan 6 has a centrifugal component and a circumferential component, and if the axial dimension f-b is reduced, the fluid pressure loss with respect to the circumferential component of the cooling air 102 is large. This is because

Therefore, in this embodiment, both axial lengths a and b are
By setting the ratio a / b of 0.7 to 0.8, both the improvement of the cooling performance of the coil end 34R and the suppression of the reduction of the cooling air flow are achieved. Of course, the above ratio can be appropriately biased depending on the model. (Experiment 1) Next, as a reference of the present embodiment, a result of examining the relationship between the axial length a of the coil end 34R of the stator coil and the stator coil temperature in the conventional alternator (see FIG. 4) will be shown.

However, the outer diameter of the centrifugal fan 6 is φ90.8.
mm, the number of revolutions is 3500 rpm, and the blowing temperature is about 15
The f of the fan is 25.1 mm at 0 ° C. As for the axial length a of the coil end 34R, it can be seen that the temperature of the stator coil decreases as the value of a increases in the range where f-a is secured to some extent. (Experiment 2) Next, in the conventional alternator used in Experiment 1 (see FIG. 4), the axial length a of the coil end was set to 19 m.
FIG. 7 shows the results of experiments performed by changing the rotation speed of the conventional product with m, the comparative product with the axial length a of the conventional product extended to 22 mm, and the product of this embodiment.

However, the axial length a of the product of this embodiment is 19 mm,
The axial length b is 22 mm, L is 3 mm, D is 18 mm, and other conditions are the same as those of the conventional product. From this experimental result,
It can be seen that the cooling effect of the coil end 34R of this embodiment product is the best. (Experiment 3) Next, regarding the product of this example used in Experiment 2,
The axial length b is kept constant and the groove 340 is dug to form a step b-a.
4 shows the relationship between the temperature of the stator coil 34 and the air volume of the cooling air 102 when various values are changed.

When the step b-a was dug 6 mm, the cooling air volume increased by 120 cm ³ / min, and the temperature of the stator coil 34 decreased by about 5 ° C. From this, the step b-a is about 2
It was suitable to be 6 mm, preferably 3 to 5 mm. Incidentally, f, L, and D in this case are the same as above. (Embodiment 2) In the above embodiment, the groove portion 340 is formed straight in the centrifugal direction. Cooling air 1 from centrifugal fan 6
It is formed by tilting in the circumferential direction which is close to the blowing direction of 02. By doing so, the circumferential component of the cooling air 102 blown out from the centrifugal fan 6 is not sharply bent in the centrifugal direction, and the fluid pressure loss can be further reduced.
(Embodiment 3) Another embodiment will be described with reference to FIG.

In this embodiment, the end surface of the coil end 34F on the front side in FIG. 1 is also provided with irregularities in the axial direction. As a result, the coil end 34F periodically has a groove portion 341 extending in the radial direction in the circumferential direction. The effect is essentially the same as that of the first embodiment. Note that, similarly to this embodiment, in the first embodiment, the groove portion 340 may be periodically formed in the circumferential direction regardless of the overhanging portion 12b.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a vehicle AC generator according to an embodiment.

FIG. 2 is a partially enlarged plan view of a rear coil end of the stator coil shown in FIG.

3 is a partially enlarged cross-sectional view of a rear coil end of the stator coil shown in FIG.

FIG. 4 is a partially enlarged sectional view of a rear coil end of a conventional stator coil.

5 is a partially enlarged cross-sectional view of a front coil end of the stator coil shown in FIG.

FIG. 6 is a characteristic diagram showing a relationship between an axial length a and a stator coil temperature.

FIG. 7 is a characteristic diagram showing the relationship between the stator coil temperature and the number of revolutions of the product of this embodiment.

8 is a characteristic diagram showing the relationship between the step b-a, the cooling air flow rate, and the stator coil temperature of the example product of FIG.

[Explanation of symbols]

6 is a centrifugal fan (fan in the present invention), 11 is a front frame (housing), 12 is a rear frame (housing), 31 is a field iron core (rotor core), 33 is an armature iron core (stator core), and 34 is a stator coil. , 34
R is a coil end of the stator coil, w is a cooling window, P is a blowing channel, and 340 is a groove (step).

Claims (1)

[Claims] 1. A housing in which a cooling window is opened in a peripheral wall,
A stator coil wound around a stator core fixed to the housing, a rotor core rotatably held in the housing inside the stator core, and a rotor core located on the inner peripheral side of the cooling window. A fan fixed to an end surface and blowing at least a part of cooling air in a centrifugal direction, at least a part of the cooling air being blown out from the fan and being blown out between an inner end surface of the housing and a coil end of the stator coil. A rotary electric machine that passes through a passage and flows into the cooling window, wherein an end surface of the coil end of the stator coil facing the blowout flow path has a step in an axial direction.