JPH0583903A - Cooling device for electric rotary machine - Google Patents

Abstract

PURPOSE:To miniaturize a device and reduce noises without lowering a cooling effect. CONSTITUTION:The axial length size of a baffle plate 29 is set to a size approximately the same as the axial length size of a stator core 23 and the baffle plate 29 is disposed facing to the stator core 23, and width size in the circumferential direction of each end plate 30 is set to a size approximately the same as the diametral size of the stator core 23, thus inhibiting the temperature rise of a winding while suppressing air quantity.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cooling device for a rotating electric machine equipped with a cooling fan.

[0002]

2. Description of the Related Art Some rotating electric machines, such as electric motors, have a structure in which a stator and windings are forcibly cooled by a cooling fan. An example thereof is shown in FIGS. 12 to 14. On the inner surface of the stator frame 1, a stator core 3 having windings 2 is provided.
Is stuck. A rotary shaft 6 having a rotor core 5 is inserted and supported by brackets 4, 4 fixed to both ends of the fixed frame 1 via bearings 7, 7.

A pair of cooling devices 8, 8 are arranged outside the stator frame 1, which will be described below. The baffle plate 9 is attached along the outer surface of the stator frame 1 via both end plates 10 and 10 in a state of being separated from the outer surface. An air guide path 11 is formed inside the air guide plate 9 and both end plates 10, 10. A fan mounting cylinder portion 12 is formed on the baffle plate 9, and a cooling fan 13 is mounted in the mounting cylinder portion 12.

In the above structure, when the cooling fan 13 is operated, cooling air passes through the air guide passage 11 as shown by the arrow and exits from the opening 11a. As a result, the stator core 3 and the winding 2 are air-cooled.

[0005]

By the way, in an electric motor, it is important to effectively cool it with a minimum necessary flow rate. In order to improve the cooling efficiency, it is necessary to consider various factors. Assuming that the ventilation cross-sectional area of the air guide passage 11 is A, the air volume Q and the flow velocity v are inversely proportional to the ventilation cross-sectional area A as shown in the equation (1). v = Q / A (1) Further, the relationship between the wind speed v and the heat transfer coefficient α is expressed by the equation (2).

[0006]

[Equation 1] k is a proportional constant and n is a positive exponent. Stator frame 1
The relationship between the surface temperature increase width T and the above α is given by equation (3), where B is the heat transfer area and q is the amount of heat radiated from the inside of the machine. T = q / (αB) (3) Summarizing the above, equation (4) is obtained.

[0007]

[Equation 2] As will be understood from this, in order to reduce the temperature increase width T, the heat transfer area and the wind speed may be increased.

The wind speed is determined by the relationship between the pressure-air volume characteristic of the fan and the flow passage. FIG. 15 shows the relationship between the pressure-air volume characteristics of the cooling fan and the ventilation resistance and the operating air volume. P-Q characteristic line F and each ventilation resistance curve Ra of the air passage (ventilation resistance: large),
The air volume value at each intersection with Rb (ventilation resistance: medium) and Rc (ventilation resistance: small) is the operating air volume. As the flow passage area is smaller, the ventilation resistance increases and the air volume decreases, and as the flow passage area is larger, the ventilation resistance decreases and the air volume increases. FIG. 16 shows the relationship between the air volume and the winding temperature.

However, in the above-mentioned conventional structure, in order to lower the winding temperature, the idea of securing the air volume is taken. Therefore, the air guide path is enlarged, and as a result, the air guide plate is also axially arranged. However, the size of the cooling device becomes large as a whole, and the fan noise cannot be ignored. Therefore, an object of the present invention is to provide a cooling device for a rotary electric machine that can reduce the size of the device and reduce noise without reducing the cooling effect.

[0010]

A cooling device for a rotary electric machine according to the present invention comprises a wind guide plate arranged along the outer surface of a stator frame and ends arranged on both axial ends of the wind guide plate. An air guide path is formed by a plate, and a forced cooling air is supplied to this air guide path by a cooling fan to cool the stator and windings. In this case, the axial length of the air guide plate is fixed. The air guide plate is set so as to be approximately equal to the axial length of the child core, and the air guide plate is arranged corresponding to the stator core, and the width of each end plate in the circumferential direction is the diameter of the stator core. It has a feature that it is set almost equal to.

[0011]

[Function] The axial length of the baffle plate is set to be substantially equal to the axial length of the stator core, and the baffle plate is arranged corresponding to the stator core, and each end plate is arranged. By arranging at both ends of the baffle plate, the cooling air hits the outer surface of the stator frame without spreading in the axial direction, and thereafter, the circumferential width dimension of each end plate is changed to the stator core diameter dimension. Since it is set to be almost equal to, it spreads along the axial direction. As a result, the cooling effect is not reduced, and the axial length of the baffle plate is about the axial length of the stator core, so the overall size is small.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. A laminated stator core 23 having windings 22 is fixed to the inner surface of the stator frame 21. A rotary shaft 26 having a rotor core 25 is inserted and supported by brackets 24, 24 fixed to both ends of the fixed frame 21 via bearings 27, 27.

On the outside of the stator frame 21,
Cooling devices 28, 28 are disposed above and below the cooling device 28, and they have the same structure. Therefore, only the cooling device 28 on the upper side will be described. The baffle plate 29 has a semi-circular plate shape, and its axial length La is set to be substantially equal to the axial (stacking direction) length of the stator core 23. This baffle plate 29
The end plates 3 along the outer surface of the stator frame 21 so as to correspond to the stator core 23 and be spaced apart from the stator frame 21.
It is attached through 0 and 30. Both end plates 30,3
0 is located between both ends of the baffle plate 20 and the outer surface of the stator frame 21, and closes that portion. This baffle plate 29
An air guide passage 31 is formed inside by the both end plates 30, 30.

The circumferential length Lb of the end plates 30, 30 (see FIG. 2)
(See) is set to be substantially equal to the diameter of the stator core 23. The air guide plate 29 has a fan mounting tube portion 32.
Is formed, and the cooling fan 3 is provided in the mounting cylinder portion 32.
3 is attached.

In the above structure, when the cooling fan 33 is operated, the air outside the machine is sucked into the fan mounting tube portion 32, and this air, that is, the cooling air, is discharged to the air guide plate 29 as shown by the arrow. An air guide 3 composed of both end plates 30 and 30
Supplied within 1. At this time, the cooling air flows through the end plates 30 and 3
Since 0 exists, it does not spread in the axial direction and flows in the air guide passage 31 in the circumferential direction (see FIG. 2). And end plate 3
Where there is no 0 or 30, the cooling air blows out from the opening 31a while expanding in the axial direction (see FIG. 5).

Here, the axial length dimension La of the baffle plate 29 is
6 is compared with the reference example for the air flow rate of this embodiment in which the axial length of the stator core 23 is set to be substantially the same as that of the reference example.
Will be described with reference to. As a reference example, consider a case where the axial length of the baffle plate is substantially equal to the axial length of the stator core, but the circumferential length of the end plates is equivalent to the conventional one. In this case, the length of the air passage in the circumferential direction of the air guide passage (the air passage length Lj in FIG.
(Equivalent to) and the friction loss is large. Further, since the outlet passage area is small, the ventilation resistance characteristic a in this reference example is large as shown in FIG.

On the other hand, as in this embodiment, the end plates 30, 30
If the length Lb in the circumferential direction of the
(See FIG. 2) is also short and friction loss is small. Further, since the length Dh (see FIG. 5) of the outlet of the air passage becomes long, the area of the outlet flow passage becomes large and the ventilation resistance characteristic becomes low as shown by b in FIG. At this time, in the reference example and the present example, the air volume is Q in FIG.
As shown by a and Qb, there are more examples.

Further, even if the circumferential length of the end plate remains Lb, if the axial length of the baffle plate is shortened with respect to the axial length of the stator core, the ventilation resistance characteristic is shown in FIG. As shown by, the air volume is high and Qd, and when the axial length of the baffle plate is made longer than the axial length of the stator core, the ventilation resistance characteristics are low and the air volume is Qe as shown in FIG. .. FIG. 7 shows the winding temperature, and the air volume Qc shown in the figure is the air volume when the cooling fan simply blows the cooling air without the air guide plate and the end plate. Table 1 shows the relationship between the above-described dimensional forms and the air volumes Qa, Qd, Qb, Qe, and Qc.

[0019]

[Table 1]

FIG. 8 shows the change in the air volume when the circumferential length of the end plate is changed. FIG. 9 shows the temperature change of the winding when the circumferential length of the end plate is changed. Further, FIG. 10 shows a change in the air volume when the axial length of the baffle plate is changed, and FIG. 11 shows a temperature change of the winding when the axial length of the baffle plate is changed. Shows.

As can be understood from FIGS. 8 and 9, the air volume decreases as the circumferential length of the end plate increases, but the temperature of the winding decreases as the axial length of the end plate increases. However, when the axial length of the end plate reaches a length (Lb) that is substantially equal to the diameter of the stator core, the length gradually increases. Such characteristics are due to the heat transfer area B and the heat transfer coefficient α in the above-mentioned formula (3), and when the circumferential length of the end plate is changed, the end plate has a circumferential length of the baffle plate. As the length becomes shorter, the amount of cooling air flowing out in the axial direction increases and the heat transfer area increases. The air volume also increases and the winding temperature also decreases. However, if the end plate becomes too short, cooling air will be emitted in the axial direction without following the outer peripheral surface of the stator frame, and eventually the heat transfer area will decrease and the winding temperature will increase. As can be seen from this, when the circumferential length of the end plate is set to a length (Lb) which is substantially equal to the diameter dimension D of the stator core, the cooling effect is highest.

As can be understood from FIGS. 10 and 11, if the axial length of the baffle plate is increased, the ventilation area increases, the ventilation resistance decreases, and the air volume increases. And
Since the heat transfer area also increases, the winding temperature also decreases, but when the axial length of the baffle plate becomes longer than the axial length of the stator core, the winding temperature increases. Therefore, the cooling effect is highest when the axial length of the baffle plate is set to be equal to (La) the axial length of the stator core.

[0023]

As is apparent from the above description, the present invention sets the axial length of the baffle plate to be substantially equal to the axial length of the stator core, and sets the baffle plate to the stator. By arranging in correspondence with the iron core, and by setting the width dimension of each end plate in the circumferential direction to be substantially equal to the diameter dimension of the stator iron core,
The cooling effect can be maintained without increasing the air volume so much, in other words, the cooling effect can be maintained even though the axial length of the baffle plate is shortened. Therefore, the device can be downsized and the cooling fan can be used. It also has an excellent effect that it can contribute to noise reduction without requiring a large one.

[Brief description of drawings]

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

[Fig. 2] Front view in vertical section

FIG. 3 is a perspective view of a main part

FIG. 4 is a top view of essential parts.

FIG. 5 is a side view of the main part.

FIG. 6 is a diagram showing a relationship between air volume and pressure.

FIG. 7 is a diagram showing a relationship between air volume and winding temperature in each case.

FIG. 8 is a diagram showing the relationship between the circumferential length of the end plate and the air volume.

FIG. 9 is a diagram showing the relationship between the circumferential length of the end plate and the winding temperature.

FIG. 10 is a diagram showing the relationship between the axial length of the baffle plate and the air volume.

FIG. 11 is a diagram showing the relationship between the axial length of the baffle plate and the winding temperature.

FIG. 12 is a view corresponding to FIG. 1 showing a conventional example.

FIG. 13 is a view corresponding to FIG.

FIG. 14 is a view corresponding to FIG.

FIG. 15 is a diagram showing a relationship between air volume and pressure.

FIG. 16 is a diagram showing a relationship between air volume and winding temperature.

[Explanation of symbols]

Reference numeral 21 is a stator frame, 22 is a winding wire, 23 is a stator core, 25 is a rotor core, 28 is a cooling device, 29 is an air guide plate, 30 is an end plate, and 31 is an air guide path.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yasushi Ota Yasushi Mie 2121 No. 2 Sayo, Asahi-cho, Mie-gun, Mie Prefecture Toshiba Mie Factory

Claims (1)

[Claims] 1. An air guide path is formed by an air guide plate arranged along an outer surface of a stator frame and end plates arranged on both axial ends of the air guide plate. In a system in which forced cooling air is supplied by a cooling fan to cool the stator and windings, the axial length of the air guide plate is set to be approximately equal to the axial length of the stator core. A lever is provided so as to correspond to the stator core, and the width dimension of each end plate in the circumferential direction is set to be substantially equal to the diameter dimension of the stator core. Cooling system.