JPH08275417A - Cooling construction for electric rotary machine - Google Patents

Abstract

PURPOSE: To provide a cooling construction for an electric rotary machine having a high cooling performance, a simple construction and less passage resistance against a cooling gas. CONSTITUTION: This cooling construction for an electric rotary machine comprises a hollow frame 1, an air supply hole 11 for supplying a cooling gas arranged at one side in the axial direction of a frame 1, an exhaust hole 12 for cooling gas provided at the other side of the frame 1, a stator 2 fixed to the inner side of the frame 1, a plurality of slots provided at equal spacings in an outer peripheral direction of the stator 2, a stator coil 22 housed in the slots, an opening 23 for the slot, and a rotor 3 provided oppositely to the stator 2 through an air gap G. A closed portion 6 is provided at the other end portion of the slot having the opening 23, and the opening 23 is provided at the other end portion of the slot where the closed portion 6 is provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cooling structure for a rotary electric machine in which a rotor is gas-cooled.

[0002]

2. Description of the Related Art Conventionally, when a rotating electric machine, in which a rotor and a stator are opposed to each other through a gap, is cooled by forced ventilation inside a motor frame, the basic cooling structure is one side of the rotor in the axial direction. The cooling gas is supplied from the rotor, the cooling gas is passed through the air gap between the rotor and the stator, the slot opening of the stator, or the axially long slot provided on the surface of the rotor. There is also a method in which heat is taken from the surface of the stator and the rotor when the cooling gas passes through the air gap. In addition, a cooling gas supply hole communicating from the outer diameter side to the air gap is provided in the axial center of the stator, and the cooling gas is supplied to the air gap from the supply hole and exhausted to both ends of the stator. Is disclosed (for example, Japanese Utility Model Publication No. 1-71943). Further, it is disclosed that a groove or a screw is formed on the surface of the rotor to increase the surface area of the rotor, and the movement of the cooling gas is promoted by the pump action of the groove or the screw to improve the cooling capacity. (For example, the actual exploitation 63-143032
issue).

[0003]

However, in the basic cooling structure of the prior art, since the air gap of the rotary electric machine is generally narrow, the flow path resistance is large. For example, as shown in FIG. 4, the flow path resistance R for each slot pitch in the circumferential direction of the stator
₀ is represented by R ₀ = k (L / p) where p is the slot pitch, L is the length of the stator, and k is the proportionality constant. Cooling gas flows parallel to the axial direction and the length of the stator is The flow path resistance is proportional to this. When the flow rate of the cooling gas is increased, the pressure loss of the flow path becomes large, and there is a problem that it is necessary to increase the capacity of the cooling gas supply device. Also, when cooling gas is passed through the opening of the slot, the amount of cooling gas that passes through the opening increases, but the amount of cooling gas that passes through the air gap decreases compared to that without the opening, and a significant improvement in cooling capacity is expected. There was a problem that I could not. Further, in the structure in which the cooling gas is supplied from the central portion in the axial direction of the stator to the air gap, the flow path resistance in the axial direction is only about half that of the basic cooling structure, and the structure becomes complicated. There was a problem. In addition, in the structure in which the screw is provided on the surface of the rotor, the average air gap becomes large, the electrical characteristics of the rotating electric machine are deteriorated, and precision processing for forming the screw is required, which increases the number of processing steps. was there. The present invention
It is an object of the present invention to provide a cooling structure for a rotating electric machine, which has a simple structure, a low flow resistance of cooling gas, and a high cooling performance.

[0004]

In order to solve the above problems, the present invention provides a hollow frame, an air supply hole provided on one axial side of the frame for supplying cooling gas, and the other of the frames. Side exhaust holes for cooling gas, a stator fixed inside the frame, a plurality of slots provided at equal intervals in the circumferential direction of the stator, and a stator housed in the slot In a cooling structure for a rotating electric machine comprising a coil, an opening of the slot, and a rotor provided so as to face the stator via an air gap, the other end of the slot provided with the opening. Is provided with a closing part, and an opening is provided at the other end of the slot provided with the closing part.

[0005]

By the above means, the closing portions are provided at the ends of the openings of the adjacent slots on the opposite sides of each other, and the closing portion is provided on one exhaust hole side and the opening portion having no closing portion is provided on the air supply hole side. The cooled cooling gas flows in the circumferential direction of the air gap at the center of the opening, flows into an opening that has a closed portion on the side of the other air supply hole and does not have a closed portion on the side of the exhaust hole, and then from the exhaust hole side. Since the gas is discharged, the flow path resistance is reduced, and the high-speed cooling gas passes through the air gap, so that the heat transfer on the rotor surface can be enhanced.

[0006]

Embodiments of the present invention will be described below with reference to the drawings. 1 is a side sectional view showing an embodiment of the present invention, FIG.
(A), (b), (c) are respectively A- shown in FIG.
FIG. 6 is a front cross-sectional view of a slot portion taken along a cross section A, a cross section BB, and a cross section CC. In the figure, 1 is a hollow cylindrical frame, 11 is an air supply hole provided on one side in the axial direction of the frame 1, and 12 is an exhaust hole provided on the other side. 2 is a cylindrical stator fixed to the inside of the frame 1, 21 is a plurality of slots penetrating in the axial direction at equal intervals in the circumferential direction, 22 is a stator coil housed in the slot 21, and 23 is fixed It is the opening of the slot 21 that opens to the inner circumference of the child 2. Reference numeral 3 denotes a rotor provided inside the stator 2 so as to face each other via an air gap G, 4 denotes a rotating shaft to which the rotor 3 is fixed, and 5 denotes a bracket which supports the frame 1 via a bearing 51. 6 is a resin or the like at the ends of the openings 23 of the adjacent slots 21 opposite to each other, that is, on one side of the openings 23 in the axial direction, and at the ends of the openings 23 that are circumferentially alternating with the adjacent openings 23. A closed part that is filled with and closed with one opening 2
As shown in the upper half of FIG. 1, when the closing portion 6 is provided on the exhaust hole 12 side, the closing portions 6 of the adjacent opening portions 23b.
Is provided on the air supply hole 11 side as shown in the lower half of FIG. That is, as shown in FIGS. 2 (a) and 2 (c), the opening 23b having the closing portion 6 at the end on the air supply hole 11 side is
No closing portion is provided at the end portion on the exhaust hole 12 side, and the opening portion 23b
The adjacent opening portions 23a are provided with the closing portion 6 on the exhaust hole 12 side, and are not provided on the air supply hole 11 side. Therefore, in each of the openings 23, as shown in FIG. 2B, there is no filling in the central portion in the axial direction, and the cooling gas is allowed to pass therethrough.

Next, the flow of the cooling gas having such a structure will be described with reference to FIG. 3 in which the inner circumference of the stator 2 is expanded. When the cooling gas is supplied into the frame 1 from the air supply hole 11, the cooling gas passes through the end surface of the stator 2 and enters the air gap G between the stator 2 and the rotor 3 and moves toward the air supply hole 11 side. It flows in the axial direction from the opening 23a without the closing portion 6. At this time, since the flow path resistance of the entire opening 23 is smaller than the flow path resistance of the entire air gap, the cooling gas flows more in the opening 23 than in the air gap G. However, since there is the closing portion 6 on the exhaust hole 12 side of the opening portion 23a into which the cooling gas flows, the cooling gas flows out from the axial center portion of the opening portion 23a toward the air gap G. Since the opening portion 23b adjacent to the opening portion 23a into which the cooling gas flows has the closing portion 6 on the air supply hole 11 side, the direct air supply hole 11 is provided.
Cooling gas from does not enter. Therefore, the air gap G
The length of the flow path in the circumferential direction is the length between the adjacent openings 23, and is substantially the same as the slot pitch p.
Further, the length of the stator 2 is L, and the axial length of the closing portion 6 is a.
Then, the width of the flow becomes (La). Proportional constant k
Then, the flow path resistance R ₁ flowing in the air gap G in the circumferential direction is expressed by R ₁ = k {p / (La)}. Since the slot pitch p is much smaller than the length L of the stator, the flow path resistance R ₁ when flowing in the circumferential direction through the air gap G flows parallel to the axial direction of the air gap G shown in the conventional example. When compared with the flow path resistance R ₀ = k (L / p), the flow path resistance R ₁ is smaller than the flow path resistance R ₀ because (L / p)> {p / (L−a)}. . Therefore,
The cooling gas flowing out from the opening 23a into the air gap G flows in the circumferential direction with a small flow path resistance, and the adjacent exhaust hole 12
Flow into the opening 23b without the closing portion 6 on the side, and the exhaust hole 1
Emitted from 2. Thus, when the cooling gas flows between the stator 2 and the rotor 3 from the air supply hole 11 side to the exhaust hole 12 side, the cooling gas flowing into one opening flows out through the air gap in the circumferential direction. , Because it flows into the adjacent opening and is discharged from the exhaust hole side, the high-speed cooling gas that flows in the circumferential direction of the air gap increases except for the part with the closed part, and the cooling gas that cleans the rotor surface is It is possible to increase the heat transfer at the rotor surface and improve the cooling effect. Although the above embodiments have been described with respect to the rotary electric machine having the rotor inside the stator, the present invention is also applicable to the rotary electric machine having the rotor outside and the stator inside. Although the rotating electric machine with a cylindrical air gap has been described, the same applies to an axial gap type rotating electric machine in which the stator and the rotor have a planar air gap, or a cone type rotating electric machine with a conical air gap. it can.

[0008]

As described above, according to the present invention, the closing portions are provided at the opposite ends of the openings of the adjacent slots, and the cooling gas flowing into one of the openings has the air gap. Since it flows in the circumferential direction and is discharged from the other opening, high-speed cooling gas passes through the air gap, and heat transfer on the rotor surface can be enhanced. Therefore, the structure is simple, the flow resistance of the cooling gas is small, and the cooling structure of the rotating electric machine that improves the cooling effect can be provided.

[Brief description of drawings]

FIG. 1 is a side sectional view showing an embodiment of the present invention.

FIG. 2 is a front sectional view showing an embodiment of the present invention.

FIG. 3 is an explanatory view showing the flow of cooling gas in the air gap according to the embodiment of the present invention.

FIG. 4 is an explanatory diagram showing a flow of cooling gas in an air gap of a conventional example.

[Explanation of symbols]

1 frame, 11 air supply hole, 12 exhaust hole, 2 stator, 21 slot, 22 stator coil, 23, 23
a, 23b opening part, 3 rotors, 6 closing part G air gap

Claims (1)

[Claims] 1. A hollow frame, an air supply hole provided on one axial side of the frame for supplying a cooling gas, a cooling gas exhaust hole provided on the other side of the frame, and an inner side of the frame. A stator fixed to the stator, a plurality of slots provided at equal intervals in the circumferential direction of the stator, a stator coil housed in the slot, an opening of the slot, and air on the stator. In a cooling structure of a rotating electric machine comprising a rotor provided so as to face each other with a gap, a closing part is provided at the other end of the slot provided with the opening, and a slot of the slot provided with the closing part is provided. A cooling structure for a rotating electric machine, wherein an opening is provided at the other end.