JPH05137296A - Totally enclosed fan-cooled motor - Google Patents

Abstract

PURPOSE:To provide a totally enclosed fan-cooled motor in which a temperature rise of a bearing of the motor is suppressed and whichie small-sized and inexpensive. CONSTITUTION:A totally enclosed fan-cooled motor comprises a stator 2 fixed to a frame 1, a rotor 3 having a shaft 4 and arranged oppositely to the stator 2, brackets 5a, 5b so arranged as to surround the rotor 3 and having bearings 6a, 6b for supporting the rotor 3, and fans 7a, 7b mounted on the shaft 4 at the outside of the brackets 5a, 5b. A vent passage 10 opened at one end at the opposite side to a load is formed at the center of the shaft 4 and communicates at the other end with a through passage 9 formed in a boss of the fan 7b of the load side.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a totally enclosed fan motor, and more particularly to a cooling structure for a rotor of the totally enclosed fan motor.

[0002]

2. Description of the Related Art FIG. 3 is a sectional view of a conventional fully-closed outer fan type electric motor. In the figure, 1 is a frame,
A stator 2 fixed to the frame 1 is composed of an iron core 2a and a coil 2b. Reference numeral 3 is a rotor, 4 is a shaft fitted to the rotor 3, 5a and 5b are brackets, and bearings 6a and 6b are respectively housed therein, and are arranged so as to surround the rotor 3 and the like. 7a and 7b are external fan-shaped fans, which are arranged on the opposite side and the load side.
Reference numeral 8 is a shielding member, and covers 8A and 8B are attached to both sides thereof, and the ventilation holes 8a and 8B are provided in the covers 8A and 8B.
b is provided.

In the conventional fully-enclosed outer fan type electric motor having such a structure, the rotor 3 and the fan 7 are turned on when the power is turned on.
a, 7b, etc. rotate. Then, by the rotation of the fans 7a and 7b, the outside air is sucked in through the ventilation holes 8a of the cover 8A, and the cooling air flows in the direction of the arrow to cool the stator 3, the rotor 7, etc. from the frame 1 and the ventilation holes 8b. Cooling air is sent out through.

[0004]

As described above, in the conventional fully-closed outer fan type electric motor, the outer surface of the electric motor is cooled by the cooling air generated by the rotation of the fans 7a and 7b to cool the rotor 3 and the like. .. However, the cooling efficiency of the rotor 3 and the like is poor, and therefore the heat generated by the rotor 3 is conducted to the shaft 4 to raise the temperature of the bearings 6a and 6b. Particularly, in the grease-filled type bearing, deterioration of the filled grease is promoted to cause burning of the bearing, and the bearing must be replaced in a short period of time. Further, in order to keep the temperature of the bearing low, the electric motor must be large in size, which not only raises the cost but also causes the inconvenience of handling the electric motor.

In order to solve such a problem, for example, as shown in Japanese Patent Laid-Open No. 63-245239, there is a plurality of cooling holes penetrating the iron core in the longitudinal direction, and the iron core is located inside the cooling holes. There are some ventilation holes that penetrate in the longitudinal direction in the part, and this ventilation hole communicates with the radial opening provided in the iron core pusher on the leeward side, but the structure is extremely complicated, so the cost increases Was invited.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a compact and inexpensive fully-closed outer fan type electric motor while suppressing the temperature rise of the bearing of the electric motor. Is.

[0007]

A fully-enclosed fan-type electric motor according to the present invention includes a stator fixed to a frame, a rotor having a shaft and arranged to face the stator, and surrounds these. In a fully-enclosed external fan electric motor having a bracket having a bearing for supporting the rotor and having a fan attached to the shaft on the outside of the bracket, one end is at the center of the shaft on the side opposite to the load side. In addition to providing a ventilation passage opening to the air passage, the other end of this ventilation passage is connected to a through passage provided in the boss portion of the fan on the load side. Further, the inner wall of the ventilation passage is provided with a spiral groove in the direction in which the shaft advances to rotate.

[0008]

The outside air sucked into the electric motor by the rotation of the fan is sent to the ventilation passages provided on the outer circumference of the frame and bracket and the shaft, and the rotor is cooled from the frame and shaft to suppress the temperature rise of the bearing. , Is sent out through a through path or the like. Further, since the spiral groove is provided on the inner wall of the ventilation passage provided on the shaft, the surface area for cooling is increased, and the cooling efficiency can be further improved.

[0009]

EXAMPLES Example 1. FIG. 1 is a configuration explanatory view showing an embodiment of the present invention in cross section. Note that the same or corresponding parts as those of the conventional example described in FIG. In the figure, 9 is a through passage that penetrates the boss portion of the fan 7b on the load side in the radial direction, and 10 is a ventilation passage provided at the center of the shaft 4, one end of which opens to the opposite load side and the other end of which penetrates. It is configured to communicate with the road 9.

In the fully-closed outer fan type electric motor constructed as described above, the fans 7a and 7b rotate as the shaft 4 rotates, and sucks the outside air through the ventilation hole 8a. Then, the sucked outside air is sent to the outer peripheries of the brackets 5a and 5b and the frame 1 and the ventilation passage 10 as indicated by arrows m and n, and the outside air of the arrow m cools the surfaces of the brackets 5a and 5b and the frame 1. Meanwhile, it is sent out through the ventilation hole 8b. On the other hand, the outside air indicated by the arrow n passes from the opening of the ventilation passage 10 corresponding to the tip of the shaft 4 on the anti-load side to the ventilation passage 10
Flows into the through passage 9 while cooling the shaft 4 and the like from the inside of the shaft 4. Then, the outside air sent to the through passage 9 is sent to the outside through the ventilation hole 8b.

The fan 7 is operating while the fully-closed fan motor is being driven.
Since the frame 1 and the shaft 4 are cooled by the outside air sucked by the rotation of a and 7b, the rotor 3 and the bearing 6
The temperature rise of a and 6b can be suppressed.

Example 2. FIG. 2 is a structural explanatory view showing a cross section of another embodiment of the present invention. The same parts as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted. In the figure,
Reference numeral 11 denotes an air passage provided in the central portion of the shaft 4 similarly to the air passage 10 in FIG. 1, and an inner wall thereof is provided with a spiral groove 11a in a direction in which the shaft 4 rotates.

Also in this embodiment configured as described above, the fans 7a, 7b are the same as in the case described in the first embodiment.
The outside air is sucked in by the rotation of and the outside air is sent out while cooling the frame 1, the shaft 4, etc. by the outside air. At this time, the outside air is smoothly sent into the ventilation passage 11 by the spiral groove 11a in the direction in which the shaft 4 rotates. Then, the outside air sent into the ventilation passage 11 is cooled by the spiral groove 11a and has a large surface area.
Can be cooled to further improve the cooling efficiency of the rotor 3 and the like.

The shaft 4 is used in the first and second embodiments.
The description has been given by exemplifying the case where the diameters of the ventilation passages 10 and 11 provided in the above are the same, but the openings of the ventilation passages 10 and 11 are formed so that the opening diameter increases toward the anti-load side. ,
You may comprise so that the flow of external air may be smoothed.

[0015]

As described above, according to the present invention, a ventilation passage having one end open to the anti-load side is provided in the central portion of the shaft, and the other end of the ventilation passage is provided in the boss portion of the load side fan. Since it is communicated with the shaft, it is possible to efficiently cool the rotor and the like by cooling from the inside of the shaft, and suppress an increase in the temperature of the bearing. Further, it is possible to prevent the bearing from being burnt out and to extend the period for replacing the bearing, so that it is possible to obtain a compact and inexpensive totally enclosed fan motor. further,
Since the spiral groove extending in the direction of rotation of the shaft is provided on the inner wall of the ventilation passage, the surface area for cooling is increased, and the outside air can be quickly fed into the ventilation passage, so that the cooling efficiency can be further improved.

[Brief description of drawings]

FIG. 1 is a configuration explanatory view showing a cross section of an embodiment of the present invention.

FIG. 2 is a structural explanatory view showing a cross section of another embodiment of the present invention.

FIG. 3 is a structural explanatory view showing a cross-section of a conventional fully-closed fan-type electric motor.

[Explanation of symbols]

 1 Frame 2 Stator 2a Iron core 2b Coil 3 Rotor 4 Shaft 5a, 5b Bracket 6a, 6b Bearing 7a, 7b Fan 8 Shielding member 8A, 8B Cover 8a, 8b Vent hole 9 Through passage 10, 11 Ventilation passage 11a Spiral groove

Claims (2)

[Claims] 1. A stator fixed to a frame, a rotor having a shaft and arranged to face the stator, and a bearing arranged to surround the rotor and support the rotor. A fully-closed external fan electric motor comprising a bracket provided with the fan and a fan attached to the shaft on the outside of the bracket, wherein the air passage is provided at the central portion of the shaft with one end opening to the anti-load side, and the air passage is provided. The other end of the fan is connected to a through passage provided in the boss portion of the fan on the load side. 2. The fully-enclosed outer fan type electric motor according to claim 1, wherein a spiral groove is formed on an inner wall of the ventilation passage in a direction in which the shaft advances.