JPH07170693A - Rotor of rotating electric machine - Google Patents

Abstract

PURPOSE:To provide a rotor for a rotating electric machine, whose cooling effect by a rotor fan is sufficient and which can suppress a temperature rise sufficiently including the temperature rise of a stator-coil end. CONSTITUTION:The edge of an end ring 6 is formed in a concave curved surface 6A, and the thickness in the direction of a shaft 1 of the end ring 6 is set in such a way that its outside-diameter side is thinner than its inside-diameter side. Thereby, the flow of a cooling air as indicated by an arrow (b) is obtained by a fan 4. As a result, the cooling capability around the base part 9E of a stator-coil end 9 is enhanced, and a temperature rise can be suppressed sufficiently. In addition, since a starting current can be suppressed, a starting characteristic can be enhanced.

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 rotating electric machine having an internal cooling fan blade at an end ring portion of a squirrel-cage winding, and more particularly to a rotating machine having a squirrel-cage winding by die casting. The present invention relates to a rotor of a rotary electric machine suitable for a child.

[0002]

2. Description of the Related Art Conventionally, a squirrel-cage induction motor has been mainly used as a general-purpose motor. FIG. 6 shows a conventional example of a rotating electric machine composed of a squirrel-cage induction motor. In the figure, 5 is a housing, and a stator 7 is fitted and fixed to the inside by press-fitting or the like. The end brackets 3 are attached to both ends of the housing 5.
A and 3B are fitted and fixed by bolts or the like.

Bearings 2A and 2B are provided on the respective end brackets 3A and 3B, and the rotary shaft 1 is supported by these bearings 2A and 2B. An iron core of the rotor 8 is fixed near the center of the rotating shaft 1 by fitting or the like, and a magnetic path is formed together with the iron core of the stator 7. Although not shown, the rotor 8 is provided with a cage winding integrally with the end ring 6 by die casting or the like.

Therefore, when a predetermined alternating current is supplied to the stator coil 9 provided on the stator 7, a rotating magnetic field is created, and an alternating secondary current flows through the cage winding of the rotor 8, Torque is generated and the rotary shaft 1 rotates.

FIG. 7 also shows an example of a conventional rotary electric machine in which the cross-sectional area of the end ring 6 is smaller than that of the conventional example of FIG. This conventional example is shown by enlarging only one end portion of the stator 7 and the other parts are the same as the conventional example of FIG.

By the way, when these rotary electric machines are operated, heat is generated from the stator coil 9, the stator 7, the rotor 8 and the like due to various losses, and the temperature rises. Therefore, in these conventional examples, a rotor fan (blade) 4 is provided on an end ring 6 of a squirrel cage winding (not shown) provided on the rotor 8 to form a fan for internal cooling. Then, when the rotor 8 rotates, the rotor fan 4
The air between the two is pushed out in the outer peripheral direction by the centrifugal force, whereby the air is circulated around the end portion 9 of the stator coil to promote heat dissipation and to cool it.

[0007]

The above-mentioned prior art does not take into consideration the improvement of the cooling efficiency by the rotor fan, and especially the cooling of the end portion of the stator coil is insufficient, and the temperature rise in this portion. There was a problem with. That is, in the conventional rotating electric machine, as shown in FIG. 6, the end ring 6 has a constant thickness in the rotation axis direction, and as a result, the air inside flows mainly as shown by the arrow a, It is difficult for the cooling air to flow in the vicinity 9E of the root of the stator coil end 9, and the temperature rise cannot be suppressed sufficiently.

An object of the present invention is to provide a rotor of a rotary electric machine in which a cooling effect of a rotor fan is enhanced and a temperature rise of a stator coil end can be suppressed sufficiently. .

[0009]

To achieve this object, according to the present invention, the cross-sectional shape of the end ring portion of the squirrel cage winding is made to rotate on the outer diameter side relative to the thickness dimension in the rotation axis direction on the inner diameter side. The axial thickness is reduced.

[0010]

[Function] An end ring having a cross-sectional shape in which the thickness dimension in the rotation axis direction on the outer diameter side is smaller than the thickness dimension in the rotation axis direction on the inner diameter side allows the air flow from the rotor fan to flow near the root of the stator coil end. Work to guide. As a result, the stator coil, including the root portion of the end thereof, is sufficiently exposed to the cooling air, so that the temperature rise can be surely suppressed.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The rotor of a rotary electric machine according to the present invention will be described in detail below with reference to the illustrated embodiments. FIG. 1 is an embodiment of the present invention, which is an enlarged view of only one end of a stator 7 of a squirrel cage induction motor, and the other end is also similarly configured. In FIG. 1, 6A represents a concave curved surface formed on the end face of the end ring 6 in the direction along the rotation axis 1. That is, in this embodiment, the thickness of the end ring 6 in the rotation axis direction on the outer diameter side is smaller than the thickness of the end ring 6 on the inner diameter side in the rotation axis direction.
A concave curved surface 6A is formed on the end surface of the end ring 6.

Therefore, according to the embodiment of FIG. 1, when the rotor 8 rotates and the centrifugal force acts on the air by the rotor fan 4, the centrifugal force causes all the air to flow in the direction indicated by the arrow a. The air flow to be introduced is guided along the concave curved surface 6A formed on this end face, and is also directed in the direction indicated by the arrow b.

As a result, according to this embodiment,
The cooling air is allowed to sufficiently flow to the root portion 9E of the stator coil end 9 and the vicinity of the root portion 9E, so that the stator coil end 9 is cooled substantially uniformly as a whole. Since the temperature rise is made uniform, the average temperature rise can be sufficiently suppressed.

Further, according to this embodiment, the concave curved surface 6A formed on the end surface of the end ring 6 widens the flow path of the air generated by the rotor fan 4, and further, the shape of this flow path is changed. , It has a function of smoothing according to the flow of air, so that the flow resistance of air is reduced, and as a result, the efficiency of air blow by the rotor fan 4 is improved, the air flow rate is increased, and more effective cooling is performed. The effect can be obtained.

However, if the cooling effect is the same on the other side, the size of the blades of the rotor fan 4 can be suppressed, and the windage loss can be reduced.

Next, another embodiment of the present invention will be described below. First, in FIG. 2, the end surface of the end ring 6 is
This is an example of a case where the inclined surface 6B is formed by an inclined straight line. Next, FIG. 3 shows an embodiment in which the end face is also formed with a stepped surface 6C formed by a combination of a plurality of straight lines. Further, FIG. 4 shows an embodiment in which the end face is also formed by a combination surface 6D formed by a combination of a curved line and a straight line.
Furthermore, FIG. 5 shows an embodiment in which the end face is formed by a combined surface 6D which is a combination of a curved line and a straight line. In each of the embodiments of FIGS. 2 to 5, the cross-sectional shape of the end ring 6 is, in any case, the thickness of the end ring 6 in the rotation axis direction on the outer diameter side with respect to the thickness of the inner diameter side in the rotation axis direction. It can be seen that the dimensions are made smaller.

Therefore, in any of the embodiments shown in FIGS. 2 to 5, the cooling airflow shown by the arrow b can be obtained, and as a result, the root portion 9E of the stator coil end 9 can be obtained.
Further, since the cooling air flows sufficiently, the stator coil end 9 is cooled substantially uniformly as a whole, the temperature rise is made uniform, and the average temperature rise is sufficiently suppressed. be able to.

In these embodiments, since the flow of the cooling air to the stator coil end 9 is controlled by changing the cross-sectional shape of the end ring 6, it is only necessary to change the cross-sectional shape of the end ring 6. The cooling characteristics can be arbitrarily changed, and therefore, it is possible to easily cope with various types and specifications of rotary electric machines at low cost.

By the way, in the rotating electric machine having such a squirrel-cage winding, the electric current is concentrated on the outer diameter side of the rotor end ring 6 at the time of starting. On the other hand, according to the above-described embodiment, in any case, the cross-sectional shape of the end ring 6 is such that the thickness dimension in the rotation axis direction on the outer diameter side is smaller than the thickness dimension in the rotation axis direction on the inner diameter side of the end ring 6. Made in.

Therefore, according to the embodiment of the present invention, the cross-sectional area on the outer diameter side of the end ring 6 is small, and as a result, the resistance (secondary resistance) value of the squirrel cage winding is increased at the time of starting. As a result, the starting current can be suppressed and the starting torque can be easily increased, and the starting characteristics can be sufficiently improved.

Here, the embodiments other than those described in the claims of the present invention will be listed as follows.

(1) A rotor of a rotary electric machine, wherein an end surface of the end ring is formed by an inclined surface formed by an inclined straight line.

(2) The rotor of a rotating electric machine, wherein the end surface of the end ring is formed by a combined surface composed of a combination of a curved line and a straight line.

(3) The rotor of a rotary electric machine, wherein the end surface of the end ring is formed by a combined surface composed of a combination of inclined straight lines and straight lines.

[0025]

According to the present invention, the cooling air can sufficiently flow to the root portion of the stator coil end and its vicinity, so that the stator coil end can be cooled almost uniformly as a whole. Since the temperature rise is made uniform, the average temperature rise can be sufficiently suppressed. Further, according to the embodiment of the present invention, since the blowing efficiency of the rotor fan can be improved, the air flow rate is increased and a more effective cooling effect can be obtained. On the other hand, if the cooling effect is the same, the size of the blades of the rotor fan 4 can be suppressed, so that the windage loss can be reduced.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view showing a first embodiment of a rotor of a rotary electric machine according to the present invention.

FIG. 2 is a partial cross-sectional view showing a second embodiment of the rotor of the rotary electric machine according to the present invention.

FIG. 3 is a partial sectional view showing a third embodiment of the rotor of the rotary electric machine according to the present invention.

FIG. 4 is a partial sectional view showing a fourth embodiment of the rotor of the rotating electric machine according to the present invention.

FIG. 5 is a partial cross-sectional view showing a fifth embodiment of the rotor of the rotating electric machine according to the present invention.

FIG. 6 is a cross-sectional view showing a conventional example of a rotary electric machine.

FIG. 7 is a partial cross-sectional view showing a conventional example of a rotating electric machine.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 rotating shaft 2A, 2B bearing 3A, 3B end bracket 4 rotor fan 5 housing 6 end ring 6A concave curved surface 6B inclined surface 6C step surface 6D, 6E combination surface 7 stator 8 rotor 9 stator coil end 9E stator coil Root part of the end

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoshitoshi Ishikawa 7-1, 1-1 Narashino Higashi Narashino, Narashino City, Chiba Prefecture Industrial Equipment Division, Hitachi, Ltd. (72) Shoji Senoo 7-1, 1 Higashi Narashino, Narashino City, Chiba Prefecture Issue Hitachi Industrial Co., Ltd. Industrial Equipment Division (72) Inventor Toshimitsu Okuno 7-11 Narashino Higashi Narashino, Chiba Prefecture Hitachi Industrial Co., Ltd. Industrial Equipment Division (72) Inventor Keiichiro Kaichiro 7-1 Higashi Narashino, Narashino City, Chiba Prefecture No. 1 Industrial Equipment Division, Hitachi, Ltd. (72) Inventor Yama-saki Masahide 7-1-1 Higashi Narashino, Narashino City, Chiba Prefecture Inventor, Industrial Equipment Division, Hitachi, Ltd. (72) Akihiro Sekine Narashino, Chiba Prefecture 7-1-1, Narashino, Higashi-shi, Hitachi Industrial Equipment Co., Ltd. Portion

Claims (3)

[Claims] 1. In a rotor of a rotary electric machine having fan-shaped blades on the end ring portion of a squirrel cage winding, the end ring portion of the squirrel cage winding has a cross-sectional shape of which is a thickness dimension in the rotating shaft direction on the inner diameter side. The rotor of the rotating electric machine is characterized in that the thickness dimension in the rotation axis direction on the outer diameter side is smaller than that of the rotor. 2. The rotor of a rotating electric machine according to claim 1, wherein the end ring portion of the end ring portion has a concave curved surface. 3. The rotor of a rotary electric machine according to claim 1, wherein the end face shape of the end ring portion in the rotation axis direction is composed of a plurality of flat surfaces joined by steps.