JPS60170441A - Motor - Google Patents

Abstract

PURPOSE:To substantially uniformly cool a rotor by composing a vent passage of axial and radial vent passages, thereby reducing the sectional area of a magnetic circuit of a rotor core. CONSTITUTION:A shaft 12 is provided at the axial center of a rotor 11, a rotor core 13 is secured to the shaft 12 through core retainers 14, 15 of both sides, and a fan 16 is secured to one end side of the core 13. An axial vent passage 21 is formed at the core 13 at the prescribed gap on the concentrical circle, thereby forming the first vent passage 19. The second vent passage 20 is formed of radial and axial vent passages 29, 26.

Description

[Detailed description of the invention] [Technical field of invention] The present invention relates to electric motors such as induction motors.

[Technical background of the invention and its problems]

In general, induction motors using squirrel-cage rotors are the drive source for general industrial machinery because they do not have maintenance constraints such as commutators and brushes compared to DC motors, and have a simple and robust structure. It is widely used as

In particular, in the electric railway vehicle industry, DC motors are the mainstream main motor for driving vehicles, but with the recent emergence of power electronics, AC variable speed power supplies (WVF inverter main circuit power supplies for vehicles) that can be mounted on vehicles have been developed. As a result, drive systems using the above-mentioned squirrel cage induction motor as the main drive motor are attracting attention because they are easy to maintain and inspect, have excellent power regeneration efficiency, and are highly effective in saving energy.

By the way, some conventional induction motors are constructed as shown in FIG. In this induction motor, when a three-phase current is applied to the stator coil (not shown) to create a rotating magnetic field, current flows through the rotor bar 1 and the rotor 2 starts rotating. Heat is generated in the iron core 3 due to copper loss or iron loss. Therefore, in order to suppress the temperature rise of the rotor par 1 and the rotor core 3 due to the generated heat, an axial ventilation passage 4 is provided in the rotor core 3.
By blowing cooling air through the fan 5, the heat generated in the rotor par 1 and the rotor core 3 is radiated and cooled.

However, the heat generation due to copper loss in the rotor par 1 is greater than that in the rotor core 3, and the temperature gradient in the axial direction is as shown in Figure 2. The reason why a temperature gradient occurs is that the temperature of the cooling air is low on the cooling air intake side of the axial ventilation passage 4 inside the rotor core 3, and it is possible to sufficiently cool the rotor core 3. The heat generated in the rotor 2 is absorbed in the process of flowing through the axial ventilation passage 4, and the temperature of the cooling air also rises slightly on the cooling air discharge side. This is due to the inability to cool the air.

Therefore, a temperature gradient as shown in FIG. 2 is generated in the rotor par 1, and there is a possibility that the temperature rise limit value may be exceeded in some cases. In addition, in the conventional structure of the rotor 2, the position of the axial ventilation passage 4 inside the rotor core 3 is further moved toward the rotor bar 1 due to the relationship between the core presser 6° 7 and the end ring 8 of the rotor rotor par 1. Since it is impossible to get close to the rotor par 1 on the cooling air discharge side, which has a high temperature, there is a drawback that it is not possible to sufficiently cool the rotor par 1 on the cooling air discharge side. In addition, if the number or cross-sectional area of the axial ventilation passages 4 inside the rotor core 3 is increased in order to increase the amount of ventilation in the axial ventilation passages 4 inside the rotor core 3, the magnetic circuit cross-section area of the rotor core 3 becomes smaller. Therefore, problems with characteristics arise.

[Purpose of the invention]

The present invention has been made based on the above-mentioned circumstances, and its object is to provide an electric motor in which the rotor can be cooled approximately evenly without reducing the magnetic circuit cross-sectional area of the rotor core. Our goal is to provide the following.

[Summary of the invention]

In order to achieve the above object, the present invention provides a shaft, a rotor core fixed to the shaft, and (b) a snow yider section of the trochanter core provided on the shaft side, through which cooling air is ventilated. a first and a second ventilation passage, the first ventilation passage comprising a first axial ventilation passage formed along the axial direction in the rotor core, and the second ventilation passage comprising a first axial ventilation passage formed along the axial direction of the rotor core; The passage includes a second axial ventilation passage formed in the spider portion along the axial direction and in which only the cooling air discharge side of the first axial ventilation passage is closed, and a passage in the rotor core in the radial direction. A radial ventilation passage is formed along the radial direction and communicates with the closed side of the second axial ventilation passage.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIGS. 3 to 8. Reference numeral 11 in FIGS. 3 and 4 is a rotor of the electric motor according to the present invention, and the rotor 1 is constructed as follows. That is,
A shaft 12 is provided at the axial center, and this shaft 12
In , the rotor core 13 is held down by core holders i4 on both end faces. A fan 16 is fixed to one end surface of the rotor core 13 via is. Further, near the outer periphery of the rotor core 13, a large number of rotor pars 17,
... are arranged at predetermined intervals, and end rings 18, 18 are arranged at both ends of these ports 1.7.

Further, inside the rotor core 13, first and second ventilation passages 19 and 20 are formed for passing cooling air.

That is, a plurality of first axial ventilation passages 21 are formed concentrically at predetermined intervals and pass through the rotor core 13 along the axial direction from one end surface side to the other end surface side thereof. This constitutes the first ventilation passage 20 described above.

The axial center of the rotor core 13 has a square-armed structure.
An outer cylinder 24 is fitted onto the outside with a predetermined gap between the inner cylinder 23 and the outer cylinder 24, and an axial cylinder is arranged along the axial direction in the gap between the inner cylinder 23 and the outer cylinder 24, and partitions this gap at a predetermined interval in the circumferential direction. A second axial ventilation passage 26 is formed between the inner tube 23, the outer tube 24, and the axial partition plate 25. The second axial ventilation passage 26 is closed by a closing plate 21 on the fan 16 side, that is, on the cooling air discharge side of the first axial ventilation passage 21 . Further, in the outer portion of the shaft portion 22 of the rotor core 13, near the end face on the first cooling air discharge side, the second shaft is connected through a through hole 28 formed in the outer cylinder 24. A radial ventilation passage 29 is formed that communicates with the closed side of the directional ventilation passage 26, and a radial ventilation passage 29 is formed so that this radial ventilation passage 29 and the first axial ventilation passage 2 do not communicate with each other. A partition ring 30 for partitioning the cooling air passage 26 and a guide plate 31 for guiding the cooling air from the second axial ventilation passage 26 outward in the radial direction are provided. This radial ventilation passage 29 and the second axial ventilation passage 26 form the second ventilation passage 2.
0 is configured.

Next, the operation of the above configuration will be explained.

FIG. 5 shows the state of the cooling air flowing through the first ventilation passage 19, and the cooling air with a low temperature flows through the rotor core 13.
The first ventilation passage 19 (the first axial ventilation passage 2
)) Inside, the rotor core 13 is cooled. The cooling air whose temperature has increased by absorbing the heat of the rotor core 13 is discharged from the other end of the rotor core 13. The cooling method shown in FIG. 5 is similar to that applied to conventional induction motors, and this cooling method alone cannot sufficiently suppress the temperature rise of the rotor bar 17 on the cooling air discharge side.

6 and 7 show the state of the cooling air flowing through the second ventilation passage 20, and the low temperature cooling air flows from one end side of the spider section 22 to the second axial ventilation passage 26. The second axial ventilation passage 26 is ventilated. At this time, the cooling air flowing through the second axial ventilation passage 26 is
Since the temperature rise in the spike portion 22 is significantly lower than that in the rotor core 13, the temperature rise is small. This cold cooling air with a small temperature rise hits the closed end of the second axial ventilation passage 26, changes direction, and flows through the radial ventilation passage 29 inside the rotor core 13. And the radial ventilation passage 29
The cooling air passing through is sucked up to the outside of the rotor core 13,
The rotor bar 17 on the cooling air discharge side is cooled, and the air is exhausted through the gap between the stator (not shown) and the iron core 13.

Therefore, in the two-way cooling air flow shown in FIGS. 5, 6, and 7, the cooling air intake side of the rotor core 13 is cooled by the conventional two-way cooling air flow. , the iron core part 13 and rotor bar 17 on the cooling air discharge side, which conventionally have a high temperature, have an increased heat dissipation area by providing the second ventilation passage 20, and cooling air with a small temperature rise can be blown directly onto the rotor bar 17. As a result, the cooling effect of the core 13 and the rotor bar 17 on the cooling air discharge side can be enhanced, and the rotor 11 can be cooled without reducing the magnetic circuit cross-sectional area of the rotor core 13. It can be cooled approximately evenly.

As a result, the temperature gradient of the rotor bar 17 becomes as shown in FIG. 8, and it becomes possible to sufficiently suppress the temperature rise of the rotor bar 17 within the limit value.

In addition, by suppressing the temperature rise of the rotor bar 17, ■ preventing the temperature rise of the bearing part, ■ the rotor bar 17
To prevent deformation due to thermal stress of the rotor 11, and to prevent unrestrained vibration of the rotor 11 due to thermal expansion of the rotor 11, and to extend the life of the induction motor by completely improving the reliability of insulators and metal joints. etc. can be done.

It should be noted that the present invention is not limited to the above embodiment, and for example, the ninth embodiment
As shown in the figure, the radial ventilation passage 29 of the second ventilation passage 2θ
may be provided in multiple stages, or one end of the second axial ventilation passage 26 of the second ventilation passage 20 may be closed off to the fan 16 as shown in FIG.

[Effects of the Invention] As explained above, according to the present invention, the shaft, the rotor core fixed to the shaft, the core part provided on the shaft side of the rotor core, and the cooling and a first and second ventilation passage for ventilation, the first and second ventilation passages.
The ventilation passage is composed of a first axial ventilation passage formed along the axial direction of the rotor core, and the second ventilation passage is
formed along the axial direction in the spider portion and the first
a second axial ventilation passage that is closed only on the cooling air discharge side of the axial ventilation passage; and a diameter that is formed in the rotor core along the radial direction and communicates with the closed side of the second axial ventilation passage. Since it is constructed with a directional ventilation passage, excellent effects such as being able to cool the rotor substantially evenly without reducing the magnetic circuit cross-sectional area of the rotor core can be achieved.

[Brief explanation of drawings]

FIG. 1 is a vertical cross-sectional view showing the rotor of a conventional induction motor, FIG. 2 is a diagram showing the temperature gradient of the rotor bar of a conventional induction motor, and FIGS. 3 to 8 show an embodiment of the present invention. 3 is a longitudinal sectional view showing the rotor of the induction motor, FIG. 4 is a cross sectional view, FIG. 5 is a longitudinal sectional view showing the ventilation of the first ventilation passage, and FIG. 2 is a longitudinal sectional view showing the ventilation of the ventilation passage, FIG. 7 is also a cross sectional view, FIG. 8 is a view showing the temperature gradient of the rotor par, and FIGS. 9 and 10 are different embodiments of the present invention. It is a longitudinal cross-sectional view showing an example. 1. Rotor, 12. Shaft, 3. Rotor core, 22. Spider section, 19. 1st ventilation passage, 20. 2nd ventilation passage, 2. No. 1st axial ventilation passage, 26 . . . second axial ventilation passage, 29 . . . radial ventilation passage. Applicant's Representative Patent Attorney Takehiko Suzue Figure 1 Figure 2 Figure 3 Figure 5 Figure 6 Figure 8

Claims (1)

[Claims] a shaft, a rotor core fixed to the shaft,
The rotor core includes a spider section provided on the shaft side, and first and second ventilation passages through which cooling air passes, and the first ventilation passage extends axially toward the rotor core. The second ventilation passage is formed along the axial direction along the side of the slit, and the second ventilation passage is formed along the cooling air passage of the first axial ventilation passage. The second axial ventilation passage is closed only on the discharge side, and the radial ventilation passage is formed along the radial direction of the rotor core and communicates with the closed side of the second axial ventilation passage. An electric motor featuring: