JP6789878B2 - Rotating machine - Google Patents

Description

An embodiment of the present invention relates to a rotary electric machine having a rotor in which a plurality of rotor bars are arranged in an annular shape at intervals from each other and the ends of the rotor bars are short-circuited with each other by a conductive short-circuit ring.

The rotor of an induction machine, which is a type of rotary electric machine, has a plurality of rotor bars arranged in a ring shape on a columnar iron core along the axial direction at intervals from each other, and the ends of these rotor bars are made conductive. They are short-circuited to each other by a short-circuit ring. In order to prevent the short-circuit ring from expanding due to centrifugal force during operation, a holding ring is integrally fitted and attached to the short-circuit ring.

Due to its structure, the holding ring in the rotor of such an induction machine has a small cooling surface area (heat dissipation area) and is easily heated during operation of the induction machine. Since the heated holding ring has a 0.2% decrease in yield strength, in order to prevent it, it was necessary to form it in a large shape in order to increase the heat capacity, or to use a material having high heat resistance.

Special opening and closing No. 6-153471

As described above, the holding ring of the induction machine is easily heated during operation, and there is a problem that the strength is lowered due to the temperature rise.

An object of the present invention is to provide a rotary electric machine which prevents a decrease in strength by securing a ventilation path for a holding ring and suppressing an increase in temperature thereof.

The rotary electric machine according to the embodiment of the present invention has a columnar shape, and a plurality of rotor bars along the axial direction thereof are arranged in an annular shape at intervals from each other, and the ends of these rotor bars are conductive short-circuit rings. A rotary electric machine having rotors short-circuited to each other by means of a short-circuited ring having an annular main body connected to each rotor bar and a portion near the inner circumference of the main body at the shaft end of the rotor. It has a tubular portion that extends in the direction, and a holding ring is fitted and attached to the outer periphery of the tubular portion, and the holding ring is attached to the tubular portion near the main body of the short-circuit ring. A ventilation path is formed, and the end face of the main body of the short-circuit ring and the end face of the holding ring facing the end face of the main body are arcs due to the potential difference between the short-circuit ring and the holding ring. The ventilation passages are opposed to each other at intervals that can prevent the occurrence, and are characterized in that the ventilation passages are through holes leading from the inner circumference of the tubular portion to the gap having the distance .

According to the above configuration, since the ventilation path to the holding ring is secured, the holding ring can be effectively cooled, and the strength decrease due to the high temperature can be prevented.

It is an overall block diagram of the rotary electric machine which concerns on one Embodiment of this invention. It is a perspective view which shows the shaft end portion of the rotor shown in FIG. It is sectional drawing which shows the main part structure of the part shown in FIG. It is sectional drawing which shows the main part structure in the other embodiment of this invention. It is sectional drawing which shows the main part structure in still another Embodiment of this invention. It is a left side view of FIG.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 shows the overall configuration of the rotary electric machine according to this embodiment. The rotary electric machine 11 houses a main body portion having a rotor 12 and a stator 13 in a frame 15. An air chamber 16 for cooling is integrally formed on the upper part of the frame 15. A large number of ventilation pipes 17 for heat exchange are provided in the air chamber 16, and outside air flows through these ventilation pipes 17 through ventilation covers 18 and 19 connected to the left and right sides of the air chamber 16 as shown.

That is, an external fan 21 coaxial with the rotating shaft 121 of the rotor 12 is provided in the ventilation cover 18 on the intake side on the left side of the drawing, and outside air is taken in from the intake port provided in the intake cover 22. Air is blown to a large number of ventilation pipes 17 in the air chamber 16 through the ventilation cover 18. The air that has passed through the ventilation pipe 17 passes through the ventilation cover 19 on the right side of the drawing, and is exhausted to the outside from the exhaust port provided in the ventilation cover 19, showing a so-called fully enclosed fan-shaped cooling structure.

However, the characteristic portion in the embodiment of the present invention lies in the structure of the rotor 12 portions as described below, and the present invention is not limited to the rotary electric machine adopting the above-mentioned fully enclosed fan-shaped cooling structure. Of course, it can also be applied to rotary electric machines that use a cooling structure other than a closed fan shape.

The rotor 12 has a rotor core 122 having a columnar shape and integrally formed with a rotating shaft 121, and a plurality of rotor bars 25 along the axial direction thereof are arranged in an annular shape at predetermined intervals. In FIG. 1, only the end portion of the rotor bar 25 is shown. The stator 13 has a stator core 131 forming a cylindrical shape and a stator winding 26. The inner peripheral surface of the stator core 131 faces the outer peripheral surface of the rotor core 122 at a distance. In FIG. 1, only the end portion of the stator winding 26 is shown.

Internal fans 28 are provided on the left and right portions of the rotating shaft 121 of the rotor 12 in the frame 15, and the air in the frame 15 is ventilated along the axial direction of the rotor 12 (not shown). Blow through the road towards its center. The air blown toward the center is passed into the air chamber 16 through ventilation ducts (not shown) formed along the radial directions of the rotor core 122 and the stator core 131 in several axial directions. It flows. A baffle plate 161 is provided in the air chamber 16, and the air flowing from the stator core 131 into the air chamber 16 is distributed to the left and right as shown by arrows, and along the inner surfaces of the left and right walls shown in the air chamber 16. And lowers to form a circulation path back into the frame 15.

In this way, the air in the frame 15 is allowed to flow into the air chamber 16 through the rotor 12 and the stator 13, and is brought into contact with the outer surfaces of a large number of ventilation pipes 17 in the air chamber 16 to exchange heat, and again in the frame 15. By returning to, the heat generated from the rotor 12 and the stator 13 is effectively ventilated and cooled during operation.

As described above, the rotor 12 has a columnar rotor core 122, and a plurality of rotor bars 25 along the axial direction thereof are arranged in an annular shape at predetermined intervals, and their ends are arranged in an annular shape in FIG. As shown by, it protrudes from the end face of the rotor core 122. The ends of these plurality of rotor bars 25 are arranged in an annular shape and are short-circuited with each other by a conductive short-circuit ring. Hereinafter, the structure of the short-circuit ring will be described with reference to FIGS. 2 and 3.

FIG. 2 shows an end short-circuit structure of a plurality of rotor bars 25, and FIG. 3 shows a cross-sectional structure of a portion to which one rotor bar 25, which is a main part thereof, is connected. As shown in FIG. 2, a plurality of rotor bars 25 are arranged in an annular shape at predetermined intervals, and each end of the rotor bars 25 is connected to a short-circuit ring 31 made of a conductive material and short-circuited with each other. ..

As shown in FIG. 3, the short-circuit ring 31 has an annular main body portion 311 connected to each rotor bar 25, and a portion of the main body portion 311 near the inner circumference (lower surface in the drawing) on the left side (rotation shown in FIG. 1). It has a tubular portion 312 extending in the axial end direction of the child 12. Further, a holding ring 32 is fitted and attached to the outer circumference of the tubular portion 312. As the holding ring 32, for example, a stainless steel material having high mechanical strength is used.

The end surface 311a of the main body 311 of the short-circuit ring 31 and the end surface 32a of the holding ring 32 facing the end surface 311a of the main body 311 are configured to face each other with a predetermined distance g. The predetermined interval g is an interval (about several millimeters) that can prevent arc generation due to a potential difference between the short-circuit ring 31 and the holding ring 32 during operation. Further, the tubular portion 312 of the short-circuit ring 31 is provided with a through hole 35 that penetrates from the inner circumference to the outer peripheral surface and leads to a gap having an interval g. The through hole 35 functions as a ventilation path leading to a portion (gap having a gap g) of the holding ring 32 near the main body portion 311 of the short-circuit ring 31.

In the above configuration, when the rotary electric machine is operated, heat is generated in the rotor 12 and the stator 13 as the electricity is applied. In particular, since a large current flows at the time of startup, the generated heat is also large. In response to this generated heat, the rotation of the external fan 21 and the internal fan 28 directly connected to the rotating shaft 121 causes the outside air to flow through the ventilation pipe 17 in the air chamber 16 and the air in the frame 15 to be between the air chamber 16 and the air chamber 16. The rotor 12 and the stator 13 are cooled by circulating the rotor 12 and the stator 13.

Also at the end of the rotor bar 25, the air from the internal fan 28 shown in FIG. 1 is blown from the axial end direction of the rotor, so that air flows from the left side to the right side in the drawing of FIG. 3, and the short circuit ring 31 A part of the air in the inner peripheral portion of the air passes through the through hole 35 by centrifugal force and flows into a gap having a distance g between the end surface 311a of the main body 311 and the end surface 32a of the holding ring 32. Therefore, in the holding ring 32, in addition to the left surface and the upper surface shown in the drawing, air flows through the end surface 32a facing the main body portion 311 of the short-circuit ring 31, so that a large heat dissipation area can be secured as compared with the conventional case, and the temperature rises thereof. Can be suppressed.

That is, in the conventional structure, since there is no distance g between the main body portion 311 of the short-circuit ring 31 and the end surface 32a of the holding ring 32, the holding ring 32 cannot secure a sufficient heat dissipation area, and the through through the distance g. Since there was no hole 35, the cooling effect due to ventilation could not be expected. Further, since the above-mentioned interval g is not provided, the short-circuit ring 31 and the holding ring 32 face each other with a minute gap, so that an arc may be partially generated due to the potential difference between them, which may cause damage. In addition, heat generated by the arc is also added, and the holding ring 32 is remarkably heated.

On the other hand, in this embodiment, as described above, the distance g (several millimeters) between the end face 311a of the main body 311 of the short-circuit ring 31 and the end face 32a of the holding ring 32 can prevent the arc generation due to the potential difference between them. Since they face each other while maintaining a gap having a degree), an arc is not generated during this period, damage due to the arc can be prevented, and heating due to the generation of the arc can be prevented. Further, since the tubular portion 312 of the short-circuit ring 31 is provided with the through hole 35 leading to the gap having the interval g as a ventilation path, the end surface 32a of the holding ring 32 can be effectively ventilated and cooled, and the heat dissipation area can be increased. Along with the increase, heating of the holding ring 32 can be suppressed.

By effectively cooling the holding ring 32 in this way, it is possible to prevent a decrease in strength due to an increase in temperature. Further, by forming a gap having a gap g between the holding ring 32 and the short-circuit ring 31, it is possible to reduce the heat and current flowing from the short-circuit ring 31 to the holding ring 32.

The larger the number of through holes 35 that function as ventilation passages, the greater the ventilation effect, but in relation to the mechanical strength, one for every 10 degrees for an inscribed angle of 360 degrees, or 118 rotor bars. In this case, it may be provided at a ratio of about 1 to 3 rotor bars. FIG. 4 shows an embodiment in which the length of the tubular portion 312 of the short-circuit ring 31 in the axial direction is large. In this case, the holding ring 32 fitted to the outer circumference of the tubular portion 312 also has a large axial length. Therefore, the holding ring 32 is provided with a ventilation hole 37 penetrating in the radial direction in a portion of the short-circuit ring 31 near the main body portion 311. On the other hand, the tubular portion 312 of the short-circuit ring 31 is provided with a through hole 35 that penetrates from the inner peripheral surface to the outer peripheral surface near the main body portion 311 and leads to the ventilation hole 37. That is, the tubular portion 312 of the short-circuit ring 31 is formed with a through hole 35 leading to the portion (vent hole 37) of the holding ring 32 near the main body portion 311 of the short-circuit ring 31, which functions as a ventilation path.

Even with this configuration, the air from the inner peripheral side of the tubular portion 312 of the short-circuit ring 31 has a through hole 35 in the ventilation hole 37 provided in the portion of the holding ring 32 near the main body portion 311 of the short-circuit ring 31. Since it flows through, it can be effectively ventilated and cooled, and it is possible to prevent a decrease in strength due to an increase in the temperature of the holding ring 32.

In the embodiment of FIGS. 5 and 6, the holding ring 32 has a shaft on the outer peripheral surface of the tubular portion 312 of the short-circuit ring 31 as a ventilation path leading to a portion (end surface 32a) of the short-circuit ring 31 near the main body portion 311. A ventilation groove 38 formed along the direction is provided. The ventilation groove 38 leads to a gap having a gap g between the end surface 311a of the main body portion 311 of the short-circuit ring 31 and the end surface 32a of the holding ring 32, and effectively ventilates and cools the space between them.

Further, a ventilation groove 39 formed along the axial direction thereof may be provided on the inner peripheral surface of the holding ring 32 facing the ventilation groove 38. The ventilation groove 39 also leads to a gap having a gap g between the end surface 311a of the main body portion 311 of the short-circuit ring 31 and the end surface 32a of the holding ring 32, and effectively ventilates and cools the space between them.

Further, these ventilation grooves 38 and 39 may be provided with only one of them, and in any case, air is blown from the left side of the tubular portion 312 and the holding ring 32 by the internal fan 28 shown in FIG. By flowing air through a gap having a gap g between the end surface 311a of the main body 311 of the short-circuit ring 31 and the end surface 32a of the holding ring 32, ventilation cooling can be effectively performed between them, and the strength of the holding ring 32 decreases due to the temperature rise. Can be prevented.

As described above, in each embodiment of the present invention, at least one of the holding ring 32 and the tubular portion 312 of the short-circuit ring 31 has a ventilation path (penetrating) leading to the portion of the holding ring 32 near the main body portion 311 of the short-circuit ring 31. Since the holes 35 and the ventilation grooves 38 and 39) are formed, the holding ring 32 can be effectively ventilated and cooled, the temperature rise of the holding ring during operation can be suppressed, and the strength decrease due to heating can be prevented.

Although some embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other embodiments, and various omissions, replacements, and changes can be made without departing from the gist of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are also included in the scope of the invention described in the claims and the equivalent scope thereof.

11 ... Rotor 12 ... Rotor 13 ... Stator 15 ... Frame 16 ... Air chamber 25 ... Rotor bar 31 ... Short-circuit ring 311 ... Main body 312 ... Cylindrical part 32 ... Holding ring 35, 38, 39 ... Ventilation path g ... Predetermined Interval

Claims (1)

A rotation having a columnar structure in which a plurality of rotor bars along the axial direction are arranged in an annular shape at intervals from each other, and the ends of these rotor bars are short-circuited with each other by a conductive short-circuit ring. It ’s an electric machine,
The short-circuit ring has an annular main body portion connected to each rotor bar, and a tubular portion in which a portion closer to the inner circumference of the main body portion extends in the axial end direction of the rotor.
A holding ring is fitted and attached to the outer circumference of this tubular portion.
A ventilation path leading to a portion of the holding ring near the main body of the short-circuit ring is formed in the tubular portion .
The end face of the main body of the short-circuit ring and the end face of the holding ring facing the end face of the main body face each other at intervals that can prevent arc generation due to a potential difference between the short-circuit ring and the holding ring.
The rotary electric machine is characterized in that the ventilation passage is a through hole leading from the inner circumference of the tubular portion to a gap having the interval .

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