JPH1118367A - Motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a motor capable of miniaturization and cost reduction while the motor is effectively cooled. SOLUTION: This motor is equipped with a frame 1, a main shaft 2 which is rotatably installed in the frame 1, a rotor 3 which surrounds the main shaft 2 and is collectively fixed to it, and a stator 3 which surrounds the rotor 3. Circulation flow channels for circulating cooling fluid in terminal spaces 11, 12, by connecting the two spaces 11, 12 which are formed in both ends of the stator 4 and the rotor 3 in the axial direction are formed. At least one of the circulating flow channels is formed as a shaft hole 20 of the main shaft 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure for improving a motor cooling method.

[0002]

2. Description of the Related Art Due to the structure of a motor, heat generated by a core and a coil of a stator, which is fixed outside, is easily released. However, the rotor core, which is a rotating body, is supported by bearings in air having poor heat conductivity in the frame. For this reason, even when cooling water exists around the frame as in an underwater motor, the heat generated by the rotor is difficult to escape to the outside, and the rotor may generate more heat than expected, leading to coil damage.

FIG. 3 shows a motor that efficiently discharges heat from a motor rotor to the outside. This is because the main shaft 2 is located in the space inside the cylindrical frame 1.
And a rotor 3 surrounding the main shaft and integrally attached to the main shaft, and a stator 4 surrounding the rotor 3.

[0004] Inside the frame 1, end spaces (core chambers) 11 and 12 are formed on both sides in the axial direction, and a rotor ventilation passage 6 is formed between the main shaft 2 and the rotor 3. Is formed, and a frame ventilation passage 8 is formed inside the ridge 7. The main shaft 2 is integrally provided with a fan 5 for circulating gas inside the two end spaces via the ventilation passages (circulation passages) 6 and 8.

Further, plate-like fins 10 protruding outward are formed on an end ring 9 constituting an end surface of the rotor 3, thereby reducing an area for heat exchange between the rotor 3 and flowing gas. It increases the cooling efficiency.

In this motor, the cooling air discharged in the outer peripheral direction by the fan 5 with the rotation of the rotor 3 is led to the frame ventilation passage 8, where it is cooled by the cooling water outside the frame 1, and It is introduced into the lower core chamber 11 while descending as shown by the arrow 3.
The cooled air is further sucked by the fan 5 to
It is guided to a rotor ventilation passage 6 formed between the main shaft 2 and the rotor core 3, where it rises as indicated by an arrow while taking heat generated in the rotor core 3, reaches the upper core chamber 12, and receives a fan. Return to suction port 5.

[0007]

In the conventional motor as described above, as shown in FIG. 4, the gas introduced into the rotor ventilation passage 6 by suction of the fan 5 from the lower core chamber 11 is supplied to the rotor ventilation passage. 6 is bent to the outer peripheral side by the action of the heat radiation fins 10 of the rotor core 3 provided near the entrance of the rotor core 6. Therefore, the amount of the rotor cooling air guided to the rotor ventilation passage 6 is insufficient, and the rotor core 3 is not sufficiently cooled, so that the temperature may rise more than expected.

Further, the main shaft must be formed in a special shape to provide the rotor ventilation passage, or a large number of axial holes must be provided in the vicinity of the main shaft of the rotor, so that the machining cost is increased and the radial dimension is increased. As a result, the motor becomes large as a whole. Further, a fan must be provided above the rotor, and a space for the fan must be ensured, which has also been an obstacle to downsizing and cost reduction of the motor.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has as its object to provide a motor that can achieve downsizing and cost reduction while efficiently cooling the motor.

[0010]

According to a first aspect of the present invention, there is provided a frame, a main shaft rotatably provided in the frame, a rotor integrally surrounding the main shaft, and a rotor. A motor having a surrounding stator and a circulation flow path for communicating two end spaces formed at both axial end portions of the stator and the rotor and circulating a cooling fluid through these end spaces. At least one of the circulation channels is formed as a shaft hole of the main shaft.

Thus, a shaft hole is generally formed in the main shaft along the axis thereof, and the shaft hole is used as a part of a circulation passage of air or other fluid as a cooling fluid. Need not be provided, and the entire motor can be reduced in diameter accordingly. Of course, it is necessary to supplement the rigidity by making the main shaft hollow, but the rate of increasing the diameter is small. Usually, the other of the circulation flow path is formed between the stator and the frame, and radiates heat to the outside by heat dissipation and heat dissipation from the frame.

The invention according to claim 2 is characterized in that the one circulation flow path has a centrifugal flow path extending radially from the shaft hole in one of the end spaces. Motor. Thus, the cooling fluid is caused to flow in the main shaft and circulates in the end space by utilizing the fluid transfer action generated by the centrifugal force accompanying the rotation of the motor.

According to a third aspect of the present invention, there is provided the motor according to the second aspect, wherein a fin is formed on the end face of the rotor, and the centrifugal flow path is open toward the fin. Thus, the fluid can be efficiently circulated by utilizing the suction effect of the fins of the rotor.

[0014]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a dry type underwater motor according to an embodiment of the present invention. The same parts as those in the conventional configuration are denoted by the same reference numerals, and description thereof is omitted.

As shown in FIG. 1, a shaft hole 20 is formed in the main shaft 2 along the axis, and the shaft hole 20 is opened at the upper end side and opened to the position corresponding to the fin 10 of the rotor 3 at the lower end side. Extending. At the lower end of the shaft hole 20, a plurality of centrifugal flow paths 21 further extending in the radial direction are formed. The main shaft 2 is supported by a bearing 22 attached to a top plate such that an upper end surface thereof forms a gap with the frame 1.
In the upper core chamber 1, the opening of the shaft hole 20 on the upper surface of the main shaft 2 is provided.
A communication hole 23 communicating with the second hole 2 is formed.

In this embodiment, a frame ventilation path 8 is formed between the stator 4 and the frame 1, but a rotor ventilation path between the rotor 3 and the main shaft 2 is not formed.
Therefore, no ridge is formed on the outer peripheral surface of the main shaft 2 as in the previous embodiment, and the outer diameter of the main shaft 2 and the inner diameter of the rotor 3 are reduced, and the outer diameter of the entire motor is also reduced. it can. Rather, the inner surface of the rotor 3 is brought into close contact with the outer surface of the main shaft to cool the rotor 3 by transferring heat to the main shaft 2. Although the shaft hole 20 is formed as a gas flow path, the influence on the outer diameter of the main shaft is very small.

The operation of the embodiment of the present invention will be described below. When the motor is operated, the centrifugal flow 2
1 is discharged radially outward. Due to the action of the centrifugal fluid machine of the main shaft 2, the centrifugal flow path 21, the lower core chamber 11, the frame flow path 8,
Upper core chamber 12, flow hole 23, shaft hole 20, centrifugal flow path 21
And a gas circulating flow circulating.

This circulating gas is cooled by water or outside air outside the frame 1 in the frame ventilation passage 8, and cools each part in the process of circulating through the upper core chamber 12, the shaft hole 20, and the lower core chamber 11. With such a cooling air circulation system, the main shaft 2 and the rotor core 3 can be efficiently cooled. In this embodiment, since the centrifugal flow path 21 is open toward the rotor fins 10 of the lower core chamber 11, the centrifugal effect of the rotor fins also acts synergistically to increase the amount of cooling air circulation. A higher cooling effect can be obtained.

[0019]

As described above, according to the present invention, since the shaft hole formed in the main shaft is used as a part of the circulation flow path of air or other fluid as a cooling fluid, the rotor core is cooled through the main shaft. In addition, the air in the frame can be circulated to cool the stator coil, and there is no need to provide a reciprocating circulation flow path outside the shaft, so that the entire motor can be reduced in diameter accordingly.

Further, by providing a centrifugal flow path extending in the radial direction from the shaft hole, the fluid generated by the centrifugal force generated by the rotation of the motor is used to efficiently transfer the heat generated by the rotor core with a simple cooling structure. It is possible to reduce the size of the motor by taking away the cooling of the stator coil and to eliminate the fan used conventionally, and to eliminate the special shape of the main shaft and rotor core for providing the rotor ventilation path, It can also contribute to lower prices.

Further, according to the present invention, when the performance of the already completed motor is insufficient, a cooling structure can be additionally formed on the main shaft, and a sufficient cooling effect can be imparted. The present invention is applicable not only to a dry-type underwater motor, but also to a liquid-sealed underwater motor and a land-based motor.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional view illustrating an entire configuration of a submersible motor according to a first embodiment of the present invention.

FIG. 2 is a view as viewed in the direction of arrows AA in FIG. 1;

FIG. 3A is an overall view of a conventional underwater motor, and FIG.

FIG. 4 is a cross-sectional view showing circulation of cooling air inside a lower core chamber in a conventional motor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Frame 2 Main shaft 3 Rotor 4 Stator 8 Frame ventilation path 9 End ring 10 Fin 11 Lower core chamber 12 Upper core chamber 20 Shaft hole 21 Centrifugal flow path 22 Bearing 23 Flow hole 24 Large diameter part 25 Centrifugal flow path 26 Suction flow path

Claims (3)

[Claims] 1. A frame comprising: a frame; a main shaft rotatably provided in the frame; a rotor surrounding the main shaft and integrally mounted; and a stator surrounding the rotor; 2 formed at both ends
In a motor having a circulation flow path that connects two end spaces and circulates a cooling fluid through these end spaces, at least one of the circulation flow paths is formed as a shaft hole of the main shaft. A motor characterized by the following. 2. The motor according to claim 1, wherein the one circulation flow path has a centrifugal flow path extending radially from the shaft hole in one end space. 3. The motor according to claim 2, wherein a fin is formed on the rotor end face, and the centrifugal flow path is open toward the fin.