JPS63245239A - Rotor for induction motor - Google Patents

Abstract

PURPOSE:To lower the temperatures of a leeward core rotor bar, an end ring and a coil end section by mounting a ventilation flue for cooling leewardly to a core hold-down and a core or a shaft. CONSTITUTION:A core 2 and core hold-downs 3, 4 are fitted to a shaft 1, and a hole 3b is bored at the same position as a core air hole 2b in order to pass core cooling air flowed out of the air hole 2b in the core hold-down 3. A ventilation flue 2a passing air in order to cool the leeward is formed to a fitting section with the shaft 1 in the core 2, and a ventilation flue 3a for flowing air flowed out of the ventilation flue 2a in the radial direction is shaped to the core hold-down 3. Since the air hole 2a is positioned where far from the air hole 2b to a rotor-bar 5 heat source, air at a temperature lower than the temperature of cooling air passed through the air hole 2b can be flowed through a leeward rotor bar 5. Accordingly, the temperature rises of the core 2 in the leeward and the rotor bar 5 can be inhibited.

Description

DETAILED DESCRIPTION OF THE INVENTION (Objectives of the Invention) (Industrial Application Field) The present invention relates to an improvement in a cooling structure for a rotor of an induction motor.

(Prior art and its problems) In general, induction motors using squirrel cage rotors are widely used as drive sources for general industrial use. In addition, in recent years, in the electric railway vehicle industry, induction motors (hereinafter referred to as IM) have begun to be used as main motors for driving vehicles due to the development of AC variable speed power supplies that can be mounted on vehicles.

The structure of an induction motor is, for example, published in 180468/1985.
It has been known.

An example of a conventional IM used for driving a vehicle will be briefly described in FIG.
2 are fitted.

The iron core 15 has air holes 15a for cooling the inside of the iron core at several places on the middle circumference of the iron core, and also has a rotor bar 5 and an end ring 6.7 on the outer periphery.

The stator 8 is fitted into the frame 9, and the frame 9
The stator 8 has an air (cooling air) inlet 10 at one end thereof and an air outlet 11 for discharging air at the other end.

The cooling air during the IMm transfer is drawn from the air intake port lO, and the end ring 7 and the iron core press 12. Iron core 15 and stator 8. Iron core pressing 12. The end rings 6 are cooled in this order, and the air is discharged to the outside of the frame 9 through the air outlet 11.

However, this structure has a first-order problem.

Since the cooling air flows from one side, the temperature rise in the leeward iron core and rotor bar increases, as shown in the temperature rise distribution of the conventional rotor in FIG. 4. If the temperature rise of the iron core and rotor bar is to be kept below a certain temperature, it will be restricted by the rotor bar on the leeward side, where the temperature is high.

Therefore, in consideration of the temperature rise of the leeward rotor bar, it was necessary to create an IM with a margin in other parts, and the weight of the motor increased due to the unbalanced balance, which placed restrictions on downsizing.

[Structure of the invention]

(Means for Solving the Problems) The present invention improves the cooling effect of the leeward rotor bar, suppresses the temperature rise to the same level as the windward rotor bar, balances the temperature at both ends of the rotor bar, and increases the entire IM temperature. The present invention provides a double-walled structure that reduces the temperature and eliminates the disadvantages of a unidirectional cooling system.

The present invention can lower the temperature of the leeward side core rotor bar, end ring, and coil end portion by providing a ventilation path for cooling the leeward side in addition to the core cooling air hole in the core stamping and the core or shaft.

(Example) An embodiment of the present invention is shown in Fig. 1 and an iron core with ventilation passages in Fig. 2.
Figure 3 shows the core stock with ventilation channels.

An iron core 2 and iron core pushers 3 and 4 are fitted onto a shaft 1.

A hole 3b is provided in the core press 3 at the same position as the air hole 2b for passing the core cooling air flowing out from the iron core air hole 2b.

Further, the iron core 2 is provided with a ventilation passage 2a for passing air to cool the leeward side at the fitting part with the shaft 1, and the iron core stamping 3 is provided to allow the wind flowing out from the ventilation passage 2a to flow in the radial direction. A ventilation passage 3a is provided.

With this configuration, the air hole 2a is located further away from the rotor bar heat source than the air hole 2b, so the air hole 2a is located further away from the rotor bar heat source than the air hole 2b.
Since the wind having a lower temperature than the cooling air passing through b can be exclusively flowed to the leeward rotor bar, it is possible to suppress the rise in temperature of the leeward iron core and rotor bar.

By lowering the temperature of the rotor bar on the leeward side, the temperature of the entire rotor can be lowered as shown in FIG. 4, resulting in a better condition.

(Other examples) Other embodiments of the invention are shown in FIGS. 5 to 9.

In FIG. 5, the shaft 14 is provided with a ventilation passage 14a, and the iron core press 13 is provided with a ventilation passage 13a for directing the air flowing out from the ventilation passage 14a to the rotor bar 5.

FIG. 6 shows the case of a rotor with spiders. spider 17
A ventilation passage 17a is provided therein.

FIG. 7 shows the spider 17 of FIG.

Figure 8 shows a ventilation passage 18a on the inner diameter side of the iron core 18 from the air hole 2b.
It has been established.

FIG. 9 shows the iron core 18 of FIG.

Further, a heat insulating material 20 may be placed in the ventilation passage 18a. In this case, the dedicated air hole 18a does not necessarily need to be located farther from the rotor bar heat source than the air hole 2b.

〔Effect of the invention〕

By providing fins on the core press, a large amount of dedicated cooling air flows through the leeward side core and rotor bar, thereby suppressing the rise in temperature of the rotor bar, and making it possible to maintain the same temperature as the lower temperature side. Conventionally, the temperature rise of the rotor was limited by the higher rotor bar, but
Since this amount is eliminated, the windward and leeward sides can be balanced, and it is possible to weigh and downsize6.

[Brief Description of the Drawings] Fig. 1 is a sectional view showing one embodiment of the rotor of the present invention;
The figure shows an example of the core of the present invention. Figure 3 shows an example of the core stamping of the present invention. Figure 4 is a graph showing the temperature distribution of the rotor of the present invention and the conventional induction motor. 5 to 9 show other embodiments of the present invention, and FIG. fI5io is a sectional view showing a conventional vl'6 Wt motive. 1...Shaft 2.15.18...Iron core 3
, 4 , 12.13.16.19... Iron core pressing 2a
, 3a, 4a, 13a, 14a, 16a, 17a, 18
aw 19a...Cooling ventilation passage 2b, 3b, 4b, 12a, 13a, 15a
- Air hole 5... Rotor bar 6, 7... End ring 8... Stator 9... Frame 10.
...Air intake port 11...Air outlet port 17...
Spider 20... Insulation agent Patent attorney Nori Chika Ken Yudo Hirofumi Mitsumata Figure 1! Figure 2 Figure 3 Windward A III K Lower 4th Figure 4/4a Figure 5 Figure 6 Figure 18 Figure 10

Claims (1)

[Claims] In the rotor of an induction motor, which has a laminated iron core on the rotor shaft, has a rotor bar on the outer periphery of the iron core, and cylindrical end rings at both ends of the rotor bar, and performs ventilation cooling by taking in cooling air from one side in the longitudinal direction. , having a plurality of cooling holes passing through the iron core in the longitudinal direction, and having a plurality of ventilation holes passing through the iron core in the longitudinal direction at a position on the inner diameter side of the cooling holes,
A rotor for an induction motor characterized by having a structure in which the ventilation hole communicates with a radial opening provided in a core pusher on the leeward side.