JPH09163682A - Rotor cooling structure of motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently cool the rotor of a high speed motor which exceeds 3,600 r.p.m., and prevent generation of thermal distortion of a rotor. SOLUTION: A rotor core part 13 is covered with a rotor can 17, maintaining a specific gap 27. Fluid channels 19, 21 are formed inside a rotor shaft 14. Apertures 20, 22 of the fluid channels 19, 21 are formed in the positions corresponding to the gap 27. From one end of the rotor shaft 14, cooling solution is injected in the fluid channels 19, 21, and made to flow through the part between the rotor core part 13 and the rotor can 17. Thereby the rotor core part 13 is cooled, and the cooling solution can be discharged from the other end of the rotor shaft 14.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotor cooling structure for an electric motor, and particularly to 3,600 r. p. m. The present invention relates to a cooling structure for cooling a rotor of a high-speed electric motor that exceeds the limit.

[0002]

2. Description of the Related Art In an electric motor, the temperature of the stator and rotor rises because a current flows through the windings of the stator and rotor. That is, when a current flows, Joule heat proportional to the square of the strength of the current and the resistance of the winding is generated in the stator and the rotor. As a result, the electric power supplied to the electric motor is consumed as Joule heat, which reduces the efficiency of the electric motor and causes the distortion of the rotor due to thermal stress. In particular, in the sealed motor casing, the temperature rise causing these harmful effects is severe. Therefore, in a high-speed electric motor that rotates a rotor at a high speed, how to cool the rotor becomes a problem.

Therefore, in the conventional electric motor, the heat generated in the rotor is transferred to the motor casing through the internal atmosphere of the motor casing by utilizing the fact that the atmosphere in the motor casing is agitated by the rotation of the rotor. The transferred heat is released from the motor casing to the outside.

Further, in recent years, there has been proposed a cooling structure in which an impeller is provided on the rotor so that the internal atmosphere of the motor casing can be more strongly agitated and the cooling rate is improved.

[0005]

However, in the conventional structure in which the rotor is cooled through the internal atmosphere of the motor casing, gas having poor thermal conductivity is used as a carrier medium for heat generated from the rotor. Therefore, there is room for further improving the cooling effect of the rotor.

Therefore, the object of the present invention is 3,600.
r. p. m. To provide a rotor cooling structure for an electric motor, which can efficiently cool the rotor of a high-speed electric motor exceeding the above range, prevent thermal distortion of the rotor, improve the efficiency of the electric motor, and further downsize the electric motor itself. is there.

[0007]

In order to solve the above problems, in the present invention, the rotor core is covered with a rotor can with a predetermined gap, a fluid passage is provided inside the rotor shaft, and a position corresponding to the gap is provided. (EN) Provided is a rotor cooling structure for an electric motor, which is provided with a passage opening portion. According to the rotor cooling structure of the electric motor of the present invention, the cooling liquid is injected into the fluid passage from one end of the rotor shaft to flow between the rotor and the can to cool the rotor, and the cooling liquid is supplied from the other end of the rotor shaft. It can be configured to be ejectable.

Further, in the present invention, an auxiliary impeller for pumping the cooling liquid can be provided in the gap between the rotor core and the rotor can.

The auxiliary impeller provided in the opening of the fluid passage provided in the rotor shaft and in the gap between the rotor core and the rotor can smoothly flows the cooling liquid into the gap between the rotor core and the rotor can. It is sufficient that the number and the shape are not limited.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a rotor cooling structure for an electric motor according to the present invention will be described in detail with reference to the drawings.

FIG. 1 is a sectional view of a vertical induction motor which is an embodiment of the rotor cooling structure of the present invention. First, the overall configuration of this water-cooled induction motor will be briefly described. The induction motor includes a stator 11 having a stator winding 12 that forms a rotating magnetic field by passing an electric current, and a rotor bar (not shown) that rotates by the rotating magnetic field formed by the stator winding 12. A rotor core 13 and an upper bearing 15 and a lower bearing 16 that support the rotor core 13 and are provided on the inner wall of the motor casing 10.
And a rotor shaft 14 whose both ends are rotatably supported by the inside of the motor casing 10.

Next, the rotor cooling structure of the electric motor of the present invention will be specifically described. Cooling of the rotor is performed, for example, by injecting a cooling liquid such as water from the lower end of the rotor shaft 14.

That is, the induction motor is provided with a rotor can 17 that covers the entire rotor core 13 with a predetermined gap 27. As a result, it is not necessary to flow the cooling liquid for cooling the rotor in the gap between the rotor and the stator,
Further, there is no fear that the cooling liquid will leak into the electric motor. An injection fluid passage 19 for injecting the cooling liquid is provided below the rotor shaft 14, and an injection opening for injecting the cooling liquid into the gap 27 between the rotor core 13 and the rotor can 17. 20 are provided. Further, above the rotor shaft 14, a discharge opening 22 for discharging the cooling liquid from the gap 27 between the rotor core portion 13 and the rotor can 14 is provided, and the discharge opening 2 is provided.
A discharge fluid passage 21 is provided which is connected to No. 2 and discharges the cooling liquid that has cooled the rotor core 13 to the outside of the electric motor.

In this embodiment, since the rotor is cooled from the lower side to the upper side, the cooling liquid injected from the lower end of the rotor shaft 14 can be discharged from the upper end of the rotor shaft 14. The auxiliary impeller 18 is provided at the lower end of the rotor can 17, that is, in the gap 27 to pump the cooling liquid upward.

The connecting member 2 is provided at the upper end and the lower end of the rotor shaft 14 so that the cooling liquid can be easily injected into and discharged from the rotating rotor shaft 14.
Auxiliary pipes 23 and 25 are provided via Nos. 4 and 26 so as not to rotate together with the rotor shaft 14.

Although not shown, the two auxiliary pipes 23 and 25 provided on the rotor shaft 14 are connected to each other through a pressurizing pump, a cooling device or the like to circulate the cooling liquid and efficiently. The rotor core 13 can be cooled.

The operation of the electric motor having the rotor cooling structure having the above structure will be described below.

First, after starting the electric motor, the cooling liquid is injected from the auxiliary pipe 23 into the injection fluid passage 19 of the rotor shaft 14.

Injection fluid passage 19 of rotor shaft 14
The cooling liquid injected into the tank 2 flows into the gap 27 between the rotor core 13 and the rotor can 17 through the injection opening 20, and is pumped by the auxiliary impeller 18 that rotates as the rotor core 13 rotates. As a result, the cooling liquid flows upward in the gap 27 between the rotor 14 and the rotor can 17, and removes heat from the surface of the rotor core portion 13. Since the rotor core 13 can be cooled in this way, the occurrence of thermal strain in the rotor can be prevented. Also,
The outside of the rotor can 17 is cooled by the atmosphere inside the motor casing 10.

The cooling liquid, which has taken away heat, reaches the upper portion of the rotor core portion 13 and is discharged between the rotor core portion 13 and the rotor can 17 through the discharge opening portion 22 and the discharge fluid passage 21.
Flow into Then, it is discharged from the auxiliary pipe 25 to the outside of the electric motor through the discharge fluid passage 21.

In the present embodiment, the cooling liquid is injected so as to flow downward from above the rotor shaft 14, but the cooling liquid is injected so that it flows downward from above the rotor shaft 14. Is also good. Further, although the vertical induction motor has been described as an example in the present embodiment, it is needless to say that the rotor cooling structure of the electric motor of the present invention can be applied to other electric motors.

Although one embodiment of the present invention has been described above, it goes without saying that various improvements and modifications can be made without departing from the spirit of the present invention.

[0023]

As described above, according to the present invention,
The rotor core is covered with a rotor can with a predetermined gap, a fluid passage is provided inside the rotor shaft, and an opening of the fluid passage is provided at a position corresponding to the gap, and cooling liquid is injected into the fluid passage from one end of the rotor shaft. Since the rotor core is cooled by cooling the rotor core by circulating the rotor core portion and the rotor can, the rotor can be efficiently cooled with a simple structure. Therefore, it is possible to prevent the imbalance of the rotor due to the thermal stress, and it is possible to improve the efficiency of the electric motor itself.

Further, since the auxiliary impeller for pumping the cooling liquid is provided in the gap between the rotor core and the rotor can, the cooling liquid can efficiently flow through the gap between the rotor core and the rotor can, and the cooling efficiency can be improved. Can also be improved.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing an embodiment of a rotor cooling structure for an electric motor of the present invention.

[Explanation of symbols]

 10 Motor Casing 11 Stator 12 Stator Winding 13 Rotor Core 14 Rotor Shaft 15 Upper Bearing 16 Lower Bearing 17 Rotor Can 18 Auxiliary Impeller 19 Injecting Fluid Passage 20 Injecting Opening 21 Discharging Fluid Passage 22 Discharging Opening 23 , 25 Auxiliary pipe 24, 26 Coupling member 27 Gap

Claims (2)

[Claims] 1. A rotor core is covered with a rotor can at a predetermined gap, a fluid passage is provided inside the rotor shaft, and an opening of the fluid passage is provided at a position corresponding to the gap, and one end of the rotor shaft is provided. A cooling liquid is injected into the fluid passage to flow through the gap between the rotor core and the rotor can to cool the rotor core, and the cooling liquid can be discharged from the other end of the rotor shaft. A rotor cooling structure for an electric motor. 2. The rotor cooling structure for an electric motor according to claim 1, wherein an auxiliary impeller for pumping the cooling liquid is provided in the gap.