JPH10248211A - Rotary electric machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rotary electric machine which can be improved in energy density due to the temperature of a winding at the center of a stator core which becomes lower due to an increased overall heat transfer coefficient from the winding at the center of the stator core to a cooling gas from the conventional value and has a small machine size. SOLUTION: A plate-like heat pipe 26 is arranged in a single or a plurality of steps between a slot bottom-side winding 3a and a slot opening-side winding 3b of the end of a winding and the end section protruded from the end face of a stator core 2 is tilted or formed in a bent section. Therefore, the overall heat transfer coefficient from the heat radiating section at the end section of the heat pipe 26 is removed, because a cooling gas smoothly flows without coming into contact with the internal surface of the pipe 26 and hardly forms a stagnated part. In addition, the heat radiating area of the end of the pipe 26 increases.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotating electric machine.

[0002]

2. Description of the Related Art FIG. 11 is a cross-sectional view of an open-type rotary electric machine showing a conventional example, in which (a) is a cross-sectional view of the entire rotary electric machine, (b) is a cross-sectional view of a stator with a heat pipe inserted, and (c) is a cross-sectional view. FIG. 3D is a diagram showing the winding temperature distribution of the average of the inner and outer circumferences of the stator, and FIG.

In the figure, a stator core 2 is provided in a stator frame 1, and a stator winding 3 is accommodated in a slot in the stator core 2. It is formed by a side winding 3a and a slot opening side winding 3b. At both ends of the stator core 2, a holding plate 4 to be bound via an outer space piece 5.
There is a rotor core 6 containing a rotor conductor 7 on the inner peripheral side. A rotating shaft 9 is fitted on the inner periphery of the rotor core 6, and the rotating shaft 9 is
Supported by The bearing brackets 8 provided at both ends of the stator frame 1 have an inlet 11 and an outlet 12. A windbreak plate 13 provided on a bearing bracket 8 is provided in the machine, and a rotor conductor end fin 14 is provided on an axial extension of the rotor conductor 7. A wedge 15 for holding the stator winding 3 on the stator core 2
There is a plate-shaped heat pipe 16 between the slot bottom winding 3a and the slot opening winding 3b.

Generally, in a plate-shaped heat pipe, a refrigerant sealed in a hollow portion boils at a high temperature portion and condenses at a low temperature portion, and a gaseous phase and a liquid phase vibrate actively in the axial direction of the hollow portion. Heat transport is performed with a small temperature difference from the heat receiving portion, which is a high temperature portion, to the heat radiating portion, which is a low temperature portion. The heat receiving portion needs to be high enough to cause the refrigerant to boil sufficiently, and the heat radiating portion needs to have a sufficient heat transfer rate and heat transfer area for releasing the transported heat. The hollow space is arranged so as to make a U-turn at each end, and a plurality of hollow spaces exist in the width direction of the heat pipe, and both ends are sealed.

A ventilation system for a rotating electric machine configured as described above will be described with reference to FIG. In FIG. 11, arrows indicate the flow of the cooling gas. The ventilation of the cooling gas in the machine is caused by the pressure increasing effect of the rotor conductor end fins 14. The cooling gas sucked into the machine from the intake port 11 of the bearing bracket 8 passes near the end of the rotor conductor 7 and travels from the end of the stator winding 3 to the exhaust port 12. On the other hand, in such a rotating electric machine,
Iron loss in stator core 6 and stator core 2, stator winding 3,
Thermal loss such as copper loss occurs in the rotor conductor 7 and friction loss occurs in the bearing 10.

A part of the loss generated in the stator core 2 is radiated to the cooling gas from the core end and the inner and outer surfaces of the stator core 2. Further, part of the loss generated in the stator winding 3 is also radiated to the cooling gas from the winding end protruding from the end face of the stator core 2. Most of the remaining loss generated in the stator core 2 and the stator winding 3 is generated by the plate-shaped heat pipe 6.
The heat is transferred to the end protruding through the fin.

[0007]

In the rotating electric machine having such a structure, the slot bottom winding 3a and the slot opening winding 3
The plate-shaped heat pipes 16 inserted into the space between b and projecting from the end of the iron core 2 are arranged in the circumferential direction. on the other hand,
At the end of the stator winding 3, the slot bottom winding 3 at the end of the winding
a and the cooling gas (arrow Aa) passing between the slot opening side winding 3b collides against the inner diameter side of the plate-shaped heat pipe 16 as shown in FIG. 11C, and does not flow smoothly (flow of arrow Aa). 3.) The stagnation region 16a is formed, and the heat transfer coefficient from the heat radiating portion at the end of the heat pipe 16 is not so high. Therefore, the heat transfer rate of the heat pipe 16 with respect to the cooling gas is reduced, the temperature rise value of the rotating electric machine winding 3 is increased, and the machine size is increased in order to suppress insulation and the like below the allowable temperature rise value. There was a problem.

In the present invention, what is called a plate-shaped heat pipe is a plate-shaped heat pipe which is turned in the axial direction a plurality of times without a wick and is sealed in a refrigerant in which both ends are sealed. This is a heat pipe that carries out heat transport by vibrating in a vertical direction. This heat pipe has the number of turns (the number of pairs of the heat receiving portion and the heat radiating portion that appear from end to end of the hollow portion. For example, receiving and discharging, that is, 1 if both ends are the heat receiving portion and the heat radiating portion; The larger the number, the higher the value is 2, the higher the value is 2.5 for receiving-discharging-receiving-discharging-receiving), the better the heat conductivity of the heat pipe. However, the pitch of the plurality of hollow spaces existing in the width direction of the plate-shaped heat pipe 16 has a manufacturing limit, and the number of hollow spaces in the width direction depends on the winding width (circumferential length). There was a limit, a large thermal conductivity could not be obtained, and the machine could not be sufficiently downsized.
An object of the present invention is to provide a rotating electric machine capable of reducing a temperature rise value and reducing a machine size.

[0009]

According to a first aspect of the present invention, one end of a plate-like heat pipe is protruded from an end of a stator core, and a portion between a slot bottom side winding and a slot opening side winding at the winding end is provided. One end of the plate-shaped heat pipe is inclined so that the cooling gas passing through the heat pipe can smoothly escape. By inclining one end of the plate-shaped heat pipe in this way, it is possible to smoothly flow without colliding with the inner side of the plate-shaped heat pipe, and it is difficult to form a stagnation area. Get higher. Therefore, the heat transfer coefficient from the center winding in the stator core to the cooling gas increases, and the temperature of the stator winding decreases. Further, since the end of the plate-shaped heat pipe is bent in a U-shape near the end of the winding end, the heat radiation area at the end of the heat pipe increases.

According to the second to sixth aspects of the present invention, a plurality of heat pipes are arranged between the slot bottom side winding and the slot opening side winding, and a curved portion or an end protrudes from the end of the stator core. Therefore, the heat radiation area increases and the temperature of the stator winding decreases.
In addition, since the heat radiation area is 1 and less than the heat reception area, the heat reception becomes large, the temperature rise of the heat pipe itself becomes large, the heat pipe characteristics are improved, and the cooling of the heat generating part (stator core or stator winding) is performed. improves. Furthermore, since heat pipe lengths are not formed in a variety of lengths in the sense of standardization in manufacturing, achieving this by bending straight lines so that they can be used in low-temperature conditions or other temperature characteristics. Can be.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view showing a first embodiment of the present invention. In FIG. 1, a stator core 2 containing a stator winding 3 is shown.
A plate-like heat pipe 26 having one end inclined is disposed between the slot bottom winding 3a and the slot opening winding 3b, and the inclined portion protrudes from the stator core 2 end face. It is the same as the stator core 2 end face. This inclined portion allows the cooling gas to smoothly pass between the slot bottom winding 3a and the slot opening winding 3b at the wire end.

By inclining the protruding end of the heat pipe, the following effects are obtained. Generally, assuming that the amount of heat generated by the entire rotating electric machine is q, the amount of heat transfer through the heat pipe is q1, and the amount of heat transfer from other than the heat pipe is q2, q = q1 + q2. K is the heat transfer coefficient in the heat transfer path to the gas, and K is the heat transfer coefficient in the heat transfer path from the windings other than the heat pipe to the cooling gas.
2. If the heat radiation area to each cooling gas is A1, A2, and the temperature difference δT between the winding temperature and the cooling air is Equation (1).

Q = (K1 · A1 + K2 · A2) δT (1) Further, the heat transfer rate K1 in the heat transfer path through the heat pipe is represented by the heat conductivity λ1 of the winding portion including the insulation, Assuming that the thickness is l1, its cross-sectional area is a1, the heat conductivity of the heat pipe is λ2, its length is l2, its cross-sectional area is a2, and the heat transfer coefficient from the heat pipe surface to the cooling gas is α3, There is a relationship (2).

1 / K1 = 11 · A1 / λ1 / a1 + 12 · A1 / λ2 / a2 + 1 / α3 (2) In the case of this embodiment, the cooling gas is heated by inclining the protruding heat pipe end. Since the flow smoothly flows without colliding with the inner diameter side of the pipe 26 and the stagnation region is hardly formed, the heat transfer coefficient α3 from the heat radiating portion at the end of the heat pipe increases, the heat transmission coefficient K1 increases, and the temperature difference δT decreases. Become. That is, the temperature of the stator windings is reduced by increasing the heat transfer coefficient from the center winding in the stator core to the cooling gas. As a result, the energy density can be increased and the machine size can be reduced.

FIG. 2 is a sectional view showing a second embodiment of the present invention. In the figure, a slot bottom side winding 3a and a slot opening side winding 3b of a stator core 2 containing a stator winding 3 are shown. In between, both curved portions of the plate-shaped heat pipe 26a in which both ends of the pipe are bent in a U-shape are disposed so as to protrude from the end face of the stator core 2. Since the plate-shaped heat pipe 26a is bent in a U-shape near the end of the winding end in this way, the heat radiation area at the end of the plate-shaped heat pipe 26a increases, and A1 in the equation (2) increases, The heat transmittance K1 increases and the temperature difference δT decreases. That is, the temperature of the stator windings is reduced by increasing the heat transfer coefficient from the center winding in the stator core to the cooling gas.

FIG. 3 is a sectional view showing a third embodiment of the present invention. In the figure, a slot bottom side winding 3a and a slot opening side winding 3b of a stator core 2 containing a stator winding 3 are shown. The plate-shaped heat pipe 26 in which both ends of the pipe are inclined
The two inclined portions b are disposed so as to protrude from the end face of the stator core 2. (The projections of the two inclined portions are different from those of the first embodiment.) As described above, by projecting both the inclined portions of the plate-shaped heat pipe 26b from the end surface of the stator core 2, the expression (2) of the first embodiment is obtained. λ2 increases.

FIG. 4 is a sectional view showing a fourth embodiment of the present invention. In the figure, a slot bottom winding 3a and a slot opening winding 3b of a stator core 2 containing a stator winding 3 are shown. In between, the plate-shaped heat pipe 26c bent in a U-shape has a curved portion protruding from one end face of the stator core 2, and both ends of the heat pipe 26c are the same as the end face of the stator core 2 to form the heat pipe 26c. The two windings 3a and 3b are arranged in two stages.

Then, the number of turns increases, the thermal conductivity of the heat pipe increases, λ2 in the equation (2) increases, the heat transmittance K1 increases, and the temperature difference δT decreases. Here, assuming that the heat pipe 26c inside the stator core 2 is a heat receiving area and the heat pipe 26c outside the stator core 2 is a heat radiation area, a U-shaped heat pipe 26c is formed between the windings 3a and 3b in FIG. Since there are two stages, the combination of the heat receiving area and the heat radiating area is as follows.

(Heat receiving area) → (Heat radiation area) → (Heat receiving area), where (receive) is 2 and (discharge) is 1. Then, the ratio of (receive) and (release) of the heat pipe is (receive) 2/3
It can be seen that the (radiation) becomes 1/3 and the heat radiation area is small. On the other hand, when considering heat dissipation from the heat generating portion (stator core or stator winding), the higher the temperature of the heat receiving area is, the higher the heat transfer to the heat radiating area is. High cooling efficiency. For this reason, if the temperature rise of the stator core or the stator winding, which is the heat receiving area, does not reach the heat transport temperature (temporarily called a low temperature state) at which the heat pipe exhibits high efficiency, the heat pipe may be used. Nevertheless, the cooling efficiency is poor and the target temperature cannot be expected to decrease much.

When the present embodiment is used at these low temperatures,
Since the heat radiation area is 1 and small, the heat reception is large, the temperature rise of the heat pipe itself is large, the heat pipe characteristics are improved, and the cooling of the heat generating portion (stator core or stator winding) is improved. Also, since heat pipe lengths are not formed in various lengths in the sense of standardization in manufacturing, it is necessary to achieve that by bending straight lines so that they can be used in low temperature conditions and other temperature characteristics. Can be. Further, the number and length of the bent portions of the pipe and the protruding length from the end face of the stator core 2 can be adjusted depending on the temperature state (high or low temperature) of the heat generating portion.

FIG. 5 is a sectional view showing a fifth embodiment of the present invention. In FIG. 5, a slot bottom side winding 3a and a slot opening side winding 3b of a stator core 2 containing a stator winding 3 are shown. In between, the plate-shaped heat pipe 26d bent in a U-shape has a curved portion protruding from one end face of the stator core 2 and an anti-curved portion protruding from the other end face of the stator core 2 to form a heat pipe 2d.
6d is arranged in two stages between the stator windings 3a and 3b. Then, the heat radiation area at the end of the plate-shaped heat pipe 26d is increased as compared with the fourth embodiment, A1 in the equation (2) is increased, the heat transmittance K1 is increased, and the temperature difference δT is reduced.

FIG. 6 is a sectional view showing a sixth embodiment of the present invention, in which a stator bottom winding 3a and a slot opening side stator winding 3b of a stator core 2 containing a stator winding 3 are arranged. In the meantime, the curved portion of the plate-shaped heat pipe 26h which is bent into an oval shape on the way is protruded from both end surfaces of the stator core 2, and both ends of the heat pipe 26h are abutted in the stator core 2 to form a two-stage heat pipe. It is arranged as a pipe 26h. Then
As compared with the fifth embodiment, the heat radiation area at the end of the plate-shaped heat pipe is increased, A1 in the equation (2) is increased, the heat transmittance K1 is increased, and the temperature difference δT is reduced.

FIG. 7 is a sectional view showing a seventh embodiment of the present invention. In the figure, a slot bottom side winding 3a and a slot opening side winding 3b of a stator core 2 containing a stator winding 3 are shown. In the meantime, one heat pipe is bent into an S-shape, and the bent plate-shaped heat pipe 26g is fixed to the stator core 2 by the S-shaped bent portion.
And is disposed as a three-stage heat pipe between the slot bottom winding 3a and the slot opening winding 3b. Both ends of the heat pipe 26g are flush with both ends of the stator core 2. The heat pipe 26g may be formed by connecting a plurality of U-shaped or S-shaped pipes. By arranging in this manner, the number of turns is increased and the thermal conductivity of the heat pipe is increased as compared with the above-described fourth embodiment.
2 increases, the heat transfer rate K1 increases, and the temperature difference δ
T becomes smaller.

FIG. 8 is a sectional view showing an eighth embodiment of the present invention. In this arrangement, both ends of the bent S-shaped plate-shaped heat pipe 26f are arranged so as to protrude from both end surfaces of the stator core 2 with respect to the seventh embodiment. Then, the number of turns increases as compared with the seventh embodiment, and the heat conductivity of the heat pipe 26f increases,
In Equation (2), λ2 increases, the heat transmittance K1 increases, and the temperature difference δT decreases.

FIG. 9 is a sectional view showing a ninth embodiment of the present invention. This is because a plurality of U-shaped plate-shaped heat pipes 26e of the fourth embodiment have bent portions projecting from both end surfaces of the stator core 2, and both ends of the heat pipe 26e are connected to both end surfaces of the stator core 2. The same and alternately disposed between the slot bottom winding 3a and the slot opening winding 3b, a total of 4
It is assumed that the stage is a heat pipe 26e. As described above, by using the heat pipe 26e having a total of four stages, the heat transfer area of the heat pipe 26e is increased as compared with the fourth embodiment, so that a2 in the equation (2) is increased, and the heat transmission rate K1 is increased. The temperature difference δT becomes smaller.

FIG. 10 is a sectional view showing a tenth embodiment of the present invention. In the ninth embodiment, the bent portions of the heat pipes 26i are projected from the end face of the stator core 2. Then
As compared with the ninth embodiment, the number of turns is increased, the thermal conductivity of the heat pipe 26i is increased, λ2 in the equation (2) is increased, the heat transmittance K1 is increased, and the temperature difference δT is reduced.

[0027]

According to the present invention, since the heat transfer rate from the center winding in the stator core to the cooling gas is larger than in the prior art, the temperature of the center winding in the core becomes lower and the energy density is reduced. It is possible to provide a rotating electric machine having a small machine size.

[Brief description of the drawings]

FIGS. 1A and 1B are sectional views showing a first embodiment of the present invention, wherein FIG. 1A is a sectional view of a slot, FIG. 1B is a sectional view of a stator with a heat pipe inserted, and FIG. Temperature distribution map,
(D) is a flow diagram of the cooling seal,

FIG. 2 is a view corresponding to FIG. 1 showing a second embodiment of the present invention,

FIG. 3 is a view corresponding to FIG. 1, showing a third embodiment of the present invention;

FIG. 4 is a view corresponding to FIG. 1, showing a fourth embodiment of the present invention;

FIG. 5 is a view corresponding to FIG. 1, showing a fifth embodiment of the present invention;

FIG. 6 is a view corresponding to FIG. 1, showing a sixth embodiment of the present invention;

FIG. 7 is a view corresponding to FIG. 1, showing a seventh embodiment of the present invention;

FIG. 8 is a view corresponding to FIG. 1, showing an eighth embodiment of the present invention;

FIG. 9 is a view corresponding to FIG. 1, showing a ninth embodiment of the present invention;

FIG. 10 is a diagram corresponding to FIG. 1, showing a tenth embodiment of the present invention;

FIG. 11 is a diagram corresponding to FIG. 1 showing a conventional example.

[Explanation of symbols]

1; stator frame; 2; stator core; 3; stator winding; 3a; slot bottom winding; 3b; slot opening winding; 6; rotor core; 7; rotor conductor; , 16, 26, 26a, 26b, 26c, 26d, 26
e, 26f, 26g, 26h, 26i; Plate heat pipe.

Claims (6)

[Claims] 1. A stator core in which a slot bottom winding and a slot opening winding, which are stator windings, are accommodated in a slot, and a plate-like core inserted between the slot bottom side and the slot opening side winding. In a rotating electric machine having a plate-shaped heat pipe that performs heat transport by enclosing a refrigerant in a hollow portion sealed at both ends by turning a plurality of times in the axial direction and sealing the both ends by axially turning, the wick does not have a wick. A rotating electric machine characterized in that one or both ends of a heat pipe are protruded from an end face of a stator core, and the protruding portion is formed in an inclined or U-shape. 2. A stator core in which a slot bottom side winding and a slot opening side winding which are stator windings are accommodated in a slot, and a plate-shaped core inserted between the slot bottom side and slot opening side windings. In a rotating electric machine having a plate-shaped heat pipe that performs heat transport by enclosing a refrigerant in a hollow portion sealed at both ends by turning a plurality of times in the axial direction and sealing the both ends by axially turning, the wick does not have a wick. The heat pipe is bent in a U-shape and arranged in a plurality of stages between the windings on the slot bottom side and the slot opening side, and the bent portion of the pipe projects from one end surface of the stator core, and the end of the anti-bent portion is the stator core end surface. A rotating electric machine characterized by protruding from the same end face or the stator core end face. 3. A stator core in which a slot bottom side winding and a slot opening side winding, which are stator windings, are housed in a slot, and a plate-shaped core inserted between the slot bottom side and slot opening side windings. In a rotating electric machine having a plate-shaped heat pipe that performs heat transport by enclosing a refrigerant in a hollow portion sealed at both ends by turning a plurality of times in the axial direction and sealing the both ends by axially turning, the wick does not have a wick. The heat pipe is bent into an elliptical shape with a halfway cut, and the ends of the heat pipe are abutted in the stator core to form a two-stage heat pipe between the windings on the slot bottom side and the slot opening side. A rotating electric machine characterized by projecting from both end faces of an iron core. 4. A stator core in which a slot bottom side winding and a slot opening side winding which are stator windings are accommodated in a slot, and a plate-shaped core inserted between the slot bottom side and slot opening side windings. In a rotating electric machine having a plate-shaped heat pipe that performs heat transport by enclosing a refrigerant in a hollow portion sealed at both ends by turning a plurality of times in the axial direction and sealing the both ends by axially turning, the wick does not have a wick. The S-shaped heat pipe is bent into an S-shape, and the S-shape pipe is singly or in combination, and a plurality of stages are arranged between the windings on the slot bottom side and the slot opening side. A rotating electric machine characterized in that one end of the pipe is made to protrude from the end face of the stator core or the end face of the stator core. 5. The rotating electric machine according to claim 4, wherein both ends of said plate-shaped heat pipe project from end faces of a stator core. 6. The heat pipe according to claim 2, wherein a plurality of plate-shaped heat pipes bent in a U-shape are alternately inserted between the windings on the slot bottom side and the slot opening side, and a plurality of stages of heat pipes are provided between both windings. Rotary electric machine.