JPS6026524Y2 - rotating electric machine - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a cooling structure for a rotor of a rotating electric machine, and particularly relates to a structure in which a part for sealing a refrigerant liquid is provided in a part of the rotor core to perform evaporative cooling.

Conventionally, the rotor of a rotating electric machine is generally cooled by air cooling using a fan provided on the rotor or a blower provided externally.

In order to increase the cooling effect, structures such as providing axial ventilation holes in the rotor core and providing radial tact in the rotor core are also adopted, but these structures reduce the wind pressure and loss inside the ventilation holes and ducts. Because of the large size, the required cooling air could not circulate and the desired effect could not be obtained.

On the other hand, recently, devices that apply the heat pipe principle to rotating electric machines have begun to appear.

As is already well known, a heat pipe is a method in which a refrigerant liquid is sealed inside the pipe and one end of the pipe is placed at a heat source that requires cooling.
The other side has a cooling section.The principle of operation is that the heat from the heat generating section is conducted into the pipe, and the contained refrigerant liquid absorbs this heat, evaporates, and moves to the cooling section where the pressure is lower. It is cooled down in the cooling section and returned to liquid form.

This liquid moves to the heat generating part by capillary action through a wick provided in the pipe and evaporates again.

By repeating this operation, the heat in the heat generating section is transferred to the cooling section due to a change in the state of the liquid, and the heat is dissipated.

Figure 1 shows a conventional technology in which such a heat pipe is applied to a rotating electric machine.The shaft 1 is a hollow shaft, and an appropriate amount of cooling medium 8 is sealed in this hollow part. .

The shaft 1 is provided with a rotor core 2, a rotor coil 3, and fins 4 that constitute a cooling section of the heat pipe hollow shaft.

This fin 4 is provided so as to be in contact with the outside air.

Reference numerals 5 and 6 indicate bearings, and reference numeral 7 represents the stator, which is composed of a stator yoke, stator magnetic poles, stator coils, end brackets, and the like.

The main heat sources of the rotor are iron loss generated in the rotor core 2 and copper loss generated in the rotor coil 3.

When the hollow shaft 1 rotates, the refrigerant liquid 8 is pressed against the inner wall of the hollow shaft 1 by centrifugal force, absorbs heat transferred from the rotor core 2, and evaporates.

At this time, the heat of vaporization is absorbed.

Then, this vapor moves through the space of the hollow shaft to the fin side where the pressure is lower, heat is radiated by the fins 4, and the vapor returns to liquid.

Then, due to centrifugal force, the liquid returns to the heat absorbing part even without the wick and evaporates again.

This action is repeated to exhaust the heat from the rotor to the outside of the machine.

Therefore, in order to increase the cooling effect with this structure, one of the main factors is to reduce the resistance to heat conducted from the heat generating part to the hollow shaft and its movement.

Therefore, it is necessary to increase the contact area between the hollow shaft and the rotor core, and also to increase the inner diameter of the hollow shaft to increase the contact area with the refrigerant liquid, and the thermal resistance between the rotor core and the refrigerant liquid. To reduce this, the hollow shaft wall thickness must be thin.

Of course, it is also important to improve the heat dissipation effect of the cooling fins.

However, if the shaft is made hollow to form a heat pipe, the inner diameter can only be increased within an allowable range in terms of strength.

Furthermore, since the rotor core is much larger than the shaft diameter, the resistance when heat is conducted to the shaft is also large.

Furthermore, the contact area between the rotor core and the shaft is also small, which hinders the cooling effect.

In addition, for medium-sized rotating electric machines and above, there are few cases in which the rotor core is laminated directly on the rotating shaft to increase the strength of the rotor.
A spider 9 is provided between the shaft 1 and the rotor core 2, as partially shown in Figures 2a and b, or a spider shaft with a spider configuration as shown in Figures 3a and b. 10 is usually used.

In such a case, the distance between the rotor core 2 and the shaft 1 or the Spigoo shaft 10 increases, the contact resistance increases, and the thermal resistance between the rotor core, which is the heat source, and the refrigerant liquid becomes large. increases, and the cooling effect decreases significantly.

The present invention has been made in view of the above points, and in order to eliminate the drawbacks of the above-mentioned conventional technology and improve the cooling effect, a plurality of refrigerant liquid-filled parts are provided in a part of the rotor core, and the rotation This is to effectively radiate the heat of the child to the outside of the rotating machine.

Hereinafter, one embodiment of the present invention will be described with reference to FIG.

When punching the rotor core, a plurality of axial holes 11 are formed in the rotor core 2 by laminating each punched board one by one on the shaft 1. .

Next, relatively thin metal pipes 12 with refrigerant liquid 8 sealed therein are inserted into each of the holes 11 and fixed to the rotor core 2 by an appropriate method.

Alternatively, the metal pipe 12 may be set in advance, and the core blanks may be stacked using this as a guide.

It goes without saying that the insertion length of these metal pipes 12 is preferably longer in order to increase the contact area with the rotor core 2.

At the same time, it is important that these metal pipes 12 and the rotor core 2 are in close contact with each other, and if necessary, adhesive resin or the like may be applied to the minute space between the axial hole 11 of the rotor core and the metal pipe 12. Fill by vacuum injection or other method.

Further, the other end of the metal pipe 12 that is not inserted into the axial hole 11 is provided with a necessary length so that a fin 4 for cooling can be provided.

The cooling fins 4 are formed into an annular shape as shown in FIG. 5, and are provided so as to connect a plurality of all-metal pipes 12.

In order to obtain the necessary cooling area, the cooling fins 4 are usually made of, for example, a large number of thin-walled metal disks. In such a case, as shown in FIGS. A base 13 may be provided so as to connect the two, and the fins 4 may be attached to this.

With such a configuration, the heat generated by the rotor core 2, rotor coil 3, etc. is transferred to the refrigerant that is pressed against the inner wall of the metal pipe 12 by centrifugal force, with the diameter of each part being the shortest distance. When the temperature reaches the boiling point, the liquid absorbs the heat of vaporization.

This steam then moves to the cooling side, radiates heat from the cooling fins that are in contact with the outside air, and condenses repeatedly.
Dissipates rotor heat.

In this way, by providing the metal pipe 12 that acts as a heat pipe in a part of the rotor core 2 that is the heat source, heat conduction from the heat source to the refrigerant liquid is extremely good, and the contact with the rotor core is extremely good. The area can also be greatly increased.

In addition, the cooling area of this portion can be maximized by the cooling fins provided to connect the respective pipes, so that the heat dissipation effect is good and the cooling efficiency is further improved.

It can also be applied to medium-sized rotating electric machines in which the rotor core is fixed to the shaft via a spider without any loss in performance.

Note that in order to cool the stator coils and the cooling fins, it is best to blow air into the machine as is normally done.

Of course, the effect will be further improved if used in combination with a conventional hollow rotary shaft heat pipe.

As described above, according to the present invention, the cooling effect of the rotor is greatly increased, so that it can greatly contribute to reducing the size and weight of rotating electric machines.

[Brief explanation of drawings]

Figure 1 is a sectional view of the upper half of a conventional rotating electrical machine that uses heat pipe action, Figures 2a and b, and Figure 3a. b is a cross-sectional view and a side view showing the vicinity of the conventional shaft, respectively;
Fig. 4 is a sectional view of the upper half of an embodiment of the present invention, Fig. 5 is a sectional view taken along the line ■-■, and Figs. 6a and b are longitudinal sectional views of main parts of different embodiments. FIG. 1... shaft, 2... rotor core, 3...
...Rotor coil, 4...Cooling fin, 5
...Bearing, 6...Bearing, 7...
・Representative code indicating rotor, 8...Refrigerant liquid, 9
... Spider, 10 ... Spider shaft, 11 ... Rotor core axial hole, 12 ...
. . . Metal pipe, 13 . . . Base to which the cooling fins 4 are attached.

Claims (1)

[Scope of utility model registration request] It has a rotor consisting of a rotating shaft supported by a bearing, a rotor core, a rotor coil, etc., and a plurality of axial holes are provided approximately in the middle of the rotor core, and the rotor is inserted into the rotor core so as to fit tightly into the hole. A feature is that a plurality of metal pipes are inserted, one end of these pipes protrudes from the rotor core, fins are provided in this part to connect these pipes, and an appropriate amount of refrigerant liquid is inserted into these pipes. A rotating electric machine.