JP2000078781A - Stator core for electric machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a stator core for an electric machine whose cooling effect by a refrigerant gas has been improved. SOLUTION: A stator core 1 uses ventilating ducts formed by using mainly duct pieces 2 which are formed by arranging duct piece segments 3 in a zigzag manner compared with a conventional art. The duct piece segments 3 made of a thin steel plate material is formed into a strip of a flat plate having the same width with an interval (d), and fixed to iron cores 42 arranged in such a way as to face the ventilating ducts by welding. As a result, the duct piece segments 3 have the longitudinal dimension almost equivalent to the one obtained by dividing into three the linear distance (L) from the inlet part up to outlet part of a refrigerant gas in the ventilating ducts.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stator core of an electric machine having a ventilation duct for ventilation cooling, and more particularly to an improved structure for improving a cooling effect by a refrigerant gas.

[0002]

2. Description of the Related Art There are two types of electric machines: rotary electric machines and linear electric machines. Among the rotary electric machines, those having a cylindrical rotor and those having a salient pole type rotor are widely known. However, a stator core of a conventional electric machine will be described as a typical example of a turbine generator which is a large-capacity machine having a cylindrical rotor. First, an outline of a structure mainly related to cooling of a general rotating electric machine having a cylindrical rotor will be described with reference to FIG.
Here, FIG. 4 is a longitudinal sectional view schematically showing a main part of a rotary electric machine of a general example.

In FIG. 4, reference numeral 9 denotes a cylindrical rotor 8;
Stator 7, casing 6, axial fans 69, 69
And a cooling device (not shown). A gap 91 is interposed between the outer peripheral surface of the cylindrical rotor 8 and the inner peripheral surface of the stator 7. The cylindrical rotor 8 has a rotating shaft portion 81, a rotor core portion 82 integrally formed with the rotating shaft portion 81, and having a circular outer diameter concentric with the rotating shaft portion 81, and corresponding to a two-pole machine. A pair of rotor windings 5 and 5 and holders 83 and 83
And is rotatably supported via a bearing (not shown).

In the rotating electric machine 9, each rotor winding 5 is
It is configured by using a plurality of saddle-shaped coils formed by winding a rectangular copper wire, which is a conductor having a rectangular cross section. Each saddle-shaped coil is loaded in a plurality of coil slots (not shown) formed along the circumferential direction of the outer periphery of the rotor core portion 82 in a concentric arrangement relationship with each other. A large number of ventilation holes 88 are formed in a portion of the rotor winding 5 housed in the coil slot of each saddle-shaped coil and distributed in the axial direction of the rotating shaft portion 81. The pair of rotor windings 5, 5 having the above-described structure is
Are basically symmetrical with respect to a central axis XX (shown by a dashed line in FIG. 4). The ends 89, 89, which are parts that are arranged so as to protrude from both ends of the rotor core portion 82 because they are not housed in the coil slots of the rotor winding 5, have cylindrical holders 83.
The outer peripheral side of the cylindrical rotor 8 is held, and is held so as not to be deformed by a strong centrifugal force generated when the cylindrical rotor 8 rotates.

Each axial fan 69 is provided to circulate a coolant gas (for example, air or hydrogen gas) 99 for cooling the cylindrical rotor 8 and the stator 7 in the rotating electric machine 9. In the case of, as shown in the figure, the rotor winding 5 is disposed at each of the outer positions in the axial length direction of the rotating shaft portion 81 at both ends 89 of the rotor winding 5. As is well known, the stator 7 is formed by laminating a large number of thin-plated iron core plates, and has a circular inner diameter concentric with the rotating shaft portion 81.
1 and a stator winding 72 mounted in a plurality of coil slots (not shown) formed in the stator core 71. A plurality of ventilation ducts 73 for passing the refrigerant gas 99 are formed in the stacking direction of the core plates of the stator core 71.

Next, the flow path of the refrigerant gas 99 of the casing 6 will be described. In the rotating electric machine 9, the casing 6 is circumscribed to the outer peripheral surface of the stator core 71 so that a total of 4
The partition plates 61 and 62 are arranged as shown in the drawing at an interval in the stacking direction of the core plates of the stator core 71. A plurality of cylindrical communication ducts 63 are arranged to connect the end-side partition plate 61 and the inner partition plate 62.
Respective spaces separated by the partition plate 61 and the partition plate 62 are exhaust ducts 64, 64, and the partition plates 6 on both sides.
The space delimited by 2 is a central air supply duct 65. At both ends of the casing 6, intake ducts 66, 66 are provided corresponding to the respective axial fans 69. The cooling device includes a well-known cooler that removes heat from the refrigerant gas 99 that has become high temperature by cooling the cylindrical rotor 8 and the stator 7.

[0007] Since the rotary electric machine 9 of the general example is configured as described above, the flow of each refrigerant gas 99 pressurized by each axial fan 69 firstly causes the holder 83 to be disposed. There are three major branches near where you are.
That is, the refrigerant gas flow 99A flowing directly from both ends to the gap 91 through the outer peripheral portion of each holding member 83, and the central air supply via the communication duct 63 after cooling each of both ends of the stator winding 72. A refrigerant gas flow 99B flowing into the duct 65 and a refrigerant gas flow 99C flowing into the cylindrical rotor 8 from each of the spaces between the outer peripheral surface of each of the rotating shaft portions 81 and the holder 83.

[0008] The refrigerant gas flow 99C reaches the end of the rotor core 82 while cooling the end 89 of the rotor winding 5, and most of the refrigerant gas flow 99C is coiled from this end. After flowing into the slot, the rotor winding 5 and the rotor core 8
After the cooling of the cooling water 2, the gas flows into the gap 91 sequentially from the ventilation holes 88. The refrigerant gas flow 99B flows through the ventilation duct 73 communicating with the central air supply duct 65, and the stator core 71
Further, the cooling air flows into the gap 91 from the central portion in the thickness direction of the stator core 71 while cooling the stator winding 72. In this way, each of the refrigerant gases 99 merged in the gap 91
Is a ventilation duct 7 communicating with the exhaust ducts 64, 64.
3 and reaches the exhaust ducts 64 while cooling the stator core 71 and the stator winding 72.

The refrigerant gas 99 that has reached the exhaust ducts 64 has a relatively high temperature because it has cooled the cylindrical rotor 8 and the stator 7.
The heat flows into a cooler via an exhaust wind tunnel (not shown) (provided by the cooling device) to remove heat. The refrigerant gas 99 whose heat has been removed by the cooler and has returned to a low temperature again flows into the axial fan 69 via an intake wind tunnel (not shown) (provided by the cooling device). That is, the rotating electric machine 9 of the general example circulates the refrigerant gas 99 through a cooler provided in the cooling device,
A relatively stable operating temperature state has been obtained,
Stator winding 72 excluding the portion loaded in the coil slot
The stator core 71 is cooled by the refrigerant gas 99 flowing through the ventilation duct 73.

Next, a stator core of a conventional electric machine will be described with reference to FIGS. In the description given with reference to FIGS. 5 and 6, the same parts as those of the rotary electric machine 9 of the general example shown in FIG. 4 are denoted by the same reference numerals, and the description thereof will be omitted. Here, FIG. 5 is a partial cross-sectional view showing a stator core of a conventional electric machine at a portion corresponding to a portion Q in FIG. 4, and FIG. 6 is a view showing a main part of the stator core shown in FIG. FIG. 6 is a view taken along the arrow JJ in FIG. 5.

5 and 6, reference numeral 71A denotes a plurality of core blocks 41, a plurality of ventilation ducts 73, a cylindrical core support beam 45, core pressing portions 46, 46, and a plurality of core fastening portions. 49 of the prior art. In this case, the core plate 42 used for the stator core 71A corresponds to the stator core 71A which is large because it is used for a large-capacity turbine generator, and the utilization of the material is reduced. In order to improve it, it is formed as a well-known fan-shaped iron core plate. That is, the iron core plate 42 is formed into a fan shape as shown in FIG. 6 by using a magnetic thin plate material such as a silicon steel plate as a material and processing it by a press method.

The iron core plate 42 has a stator winding (for example,
A coil slot 43 for mounting a stator coil (not shown) constituting the stator winding 72) and a tooth portion 44 which is a portion formed by sandwiching both sides of the coil slot 43 alternately. Further, they are formed at an equal pitch as shown in the figure. These coil slots 43 and teeth 4
Numeral 4 is formed on the inner peripheral surface 7a side of the stator core 71A, which is the gap (for example, the gap 91). In addition, 4
Reference numeral 21 denotes a through hole formed in the iron core plate 42 for mounting a fastening stud 491 described later. The iron core blocks 41 are formed by stacking the iron core plates 42 while arranging them in an annular shape. A ventilation duct 73 is formed between the iron core blocks 41 in the stacking direction of the iron core plates 42.

In the stator core 71A, the duct piece 4 is used in order to maintain the interval d of the ventilation duct 73 in the core plate laminating direction. This duct piece 4
It is formed in a slender flat plate shape having the same width dimension as the interval d using an iron thin plate material, and is fixed to the iron core plate 42 provided facing the ventilation duct 73 by a welding method or the like. The duct pieces 4 are arranged with their lengths along the flow direction of the refrigerant gas 99 and are arranged along the arrangement direction of the coil slots 43 (circumferential direction with respect to the inner peripheral surface 7a) ( See FIG. 6). The core pressing portion 46 is an annular press ring 47 made of a magnetic metal material such as an iron material.
And a press ring 47 made of a non-magnetic metal plate.
And a plurality of fingers 48 fixed to the side surface on the side of the iron core block 41 by a welding method or the like. Further, the iron core fastening portion 49 includes a fastening stud 491 and nuts 492 attached to both ends of the fastening stud 491.
And so on.

The stator core 71A is sequentially laminated with the core plates (including the one to which the duct piece 4 is fixed) 42 arranged in an annular shape on the inner peripheral side of the core support beam 45. Plurality of iron core blocks 4 with ventilation duct 73 interposed
Form one. These iron core blocks 41 with the ventilation duct 73 interposed therebetween are tightened from the outer surfaces of the iron core blocks 41 at both ends via the iron core pressing portions 46 by the iron core tightening portions 49 by a high surface pressure in the laminating direction of the iron core plates 42. Can be
In addition, a through hole (not shown) is formed in the iron core support beam 45 to allow the coolant gas 99 to penetrate and flow. In this case, the iron core blocks 41 disposed at both ends of the iron core plate 42 in the stacking direction are the same as those shown in FIG.
As shown in the figure, the inner diameter of the stator core 71A is gradually and gradually increased toward a portion closer to the end portion of the stator core 71A in the stacking direction of the core plates 42, so that a well-known paragraph portion is formed. Is formed.

Since the stator core 71A of the conventional example is configured as described above, the heat loss generated in the stator core 71A and the heat loss generated in the stator winding in the portion loaded in the coil slot 43 are described. Most of the iron core block 4
1 in the direction in which the iron core plates 42 are stacked,
Is transmitted to the refrigerant gas 99 by forced convection from the end face of the iron core block 41 facing the, and is removed from the stator iron core 71A. Thereby, the stator winding and the stator core 71
A can obtain a relatively stable operating temperature state.

[0016]

In the above-described electric machine using the stator core 71A according to the prior art, a relatively stable operating temperature state can be obtained, but a high-power electric machine will be obtained. Or when trying to obtain a small electric machine with the same output, the following problems emerge. That is, according to the study by the inventors, the value of the local heat transfer coefficient in the direction along the flow direction of the refrigerant gas 99 of the forced convection heat transfer when radiating heat from the end face of the iron core block 41 to the refrigerant gas 99 is: It decreases as it goes downstream of the refrigerant gas 99 (see a graph shown by a dotted line in FIG. 3 described later). This is because the thickness of the known temperature boundary layer of the refrigerant gas 99 formed in contact with the end face of the iron core block 41 increases toward the downstream side of the refrigerant gas 99. This thick layer of the temperature boundary layer is formed, and the average heat transfer coefficient value when transferring heat from the end face of the iron core block 41 to the refrigerant gas 99 is suppressed, so that the electric machine has higher output and further downsizing. Subject to restrictions.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the related art, and has as its object to provide a stator core of an electric machine in which a cooling effect by a refrigerant gas is improved.

[0018]

According to the present invention, there are provided the following objects: 1) A plurality of thin iron core plates having a plurality of coil slots formed therein for mounting stator coils are laminated, and an iron core is provided. Equipped with a ventilation duct that allows refrigerant gas to flow in the stacking direction of the plates, and the ventilation duct is fixed to an electric machine in which the intervals in the core plate stacking direction are maintained by a plurality of duct pieces arranged along the coil slot arrangement direction In the iron core, the duct piece is elongated and flat and arranged along the flow of the refrigerant gas in the length direction, and divides the linear distance from the refrigerant gas inlet to the refrigerant gas outlet of the ventilation duct into a plurality. Formed by a plurality of duct piece pieces having a length dimension to make, these duct piece pieces are arranged in a staggered manner with respect to the flow of the refrigerant gas,
Is achieved by

[0019]

Embodiments of the present invention will be described below in detail with reference to the drawings. In the following description, the same parts as those of the rotary electric machine of the general example shown in FIG. 4 and the stator core of the conventional example shown in FIGS. Omitted. FIG. 1 is a view taken along the line KK in FIG. 2 of a main part of a stator core of an electric machine according to an embodiment of the present invention, and FIG.
FIG. 5 is a partial cross-sectional view showing a stator core of an electric machine according to an example of an embodiment of the present invention at a portion corresponding to a portion Q in FIG. 4. FIG. 3 is an explanatory diagram for explaining a change in a local heat transfer coefficient value of the stator core according to the present invention along the refrigerant gas flow direction in comparison with a conventional example.

In FIGS. 1 and 2, reference numeral 1 designates a configuration in which a ventilation duct 11 is used in place of the ventilation duct 73 with respect to the conventional stator core 71A shown in FIGS.
3 is a stator core according to the present invention. Thus, the ventilation duct 11 is formed mainly using the duct piece 2. The formation position of the ventilation duct 11 with respect to the core plate lamination direction of the stator core 1 and the value of the interval d of the ventilation duct 11 with respect to the core plate lamination direction are the same as the conventional stator core 71A.
Is the same as As a feature of the present invention, the duct piece 2 used in the stator core 1 is formed by arranging a plurality of duct piece pieces 3 in a staggered manner as shown in the figure.

The duct piece 3 is formed into a thin and long flat plate having the same width dimension as the interval d by using an iron thin plate material, like the duct piece 4 according to the conventional example, and faces the ventilation duct 11. It is fixed to the iron core plate 42 provided by a welding method or the like. The difference between the duct piece 3 and the duct piece 4 is that the duct piece 3 extends from the inlet of the refrigerant gas 99 of the ventilation duct 11 (coinciding with the inner peripheral surface 7a of the iron core block 41) to the outlet of the refrigerant gas 99 ( The linear distance L up to the outer peripheral surface 1a of the core block 41 is divided into a plurality of parts (in the case of the stator core 1, divided into three parts). . In addition,
In the case of the stator core 1, in consideration of the fact that the flow of the refrigerant gas 99 is obstructed by the stator coil loaded in the coil slot 43 at the portion behind the coil slot 43, the conventional duct piece is used. 4 is applied.

The stator core 1 of the electric machine according to the embodiment of the present invention shown in FIGS. 1 and 2 has the above-described structure, and therefore flows through the portion of the ventilation duct 11 where the duct piece 2 is arranged. The refrigerant gas 99 is arranged in a staggered pattern.
The flow is disturbed by colliding with the distal end portions (shown by A and B in FIG. 1) of the duct piece 3 after the step. Due to the turbulence generated in the refrigerant gas 99, a part of the temperature boundary layer of the refrigerant gas 99 formed in contact with the end face of the iron core block 41 is separated near the distal ends (A and B) of the duct piece 3. Is done.

If a part of the temperature boundary layer of the refrigerant gas 99 is peeled off, the thickness of the temperature boundary layer at that portion becomes thinner.
As is well known, the local heat transfer coefficient value is increased. Then, the local heat transfer coefficient value once increased by the collision of the refrigerant gas 99 with the front end portion A decreases as it goes downstream of the refrigerant gas 99. Eventually refrigerant gas 99
Collides with the front end portion B, and the local heat transfer coefficient value increases again, but decreases again as it goes downstream of the refrigerant gas 99 (see FIG. 3).

According to the present invention, the inventors of the present invention consider the change in the local heat transfer coefficient value in the direction along the flow direction of the refrigerant gas 99 with respect to the forced convection heat transfer radiating heat from the end face of the iron core block 41 to the refrigerant gas 99. The case of the stator core 1 and the case of the stator core 4 according to the conventional example were studied. FIG. 3 shows a graph for qualitatively explaining the results. In FIG. 3, the horizontal axis indicates the flow position of the refrigerant gas 99 flowing through the ventilation duct 11, and the vertical axis indicates the value of the local heat transfer coefficient when heat is released from the end face of the iron core block 41 to the refrigerant gas 99. The case of the stator core 1 is indicated by a solid line graph, and the case of the stator core 4 is indicated by a dotted line graph. That is, FIG.
In the case of the stator core 1, the average heat transfer coefficient when the heat is radiated from the end face of the iron core block 41 to the refrigerant gas 99 is increased as compared with the conventional example, and the cooling by the refrigerant gas 99 is performed. The effect is improved.

As a result, in a rotating electric machine using the stator core 1, a high output can be obtained with the same physical size, and the physical size can be reduced with the same output. Then, this can be obtained by forming a duct piece using a duct piece piece having a length obtained by dividing the linear distance L from the refrigerant gas inlet portion to the refrigerant gas outlet portion into a plurality of pieces. Hardly increases. Further, the above configuration can be applied not only to a rotary electric machine but also to, for example, a linear machine.

[0026]

In the stator core of the electric machine according to the present invention, the cooling effect of the stator core by the refrigerant gas is improved by adopting the configuration described in the section of the means for solving the above problems. However, in an electric machine using the stator core, high output can be achieved with the same size, and
There is an effect that the physique can be reduced in size with the same output.

[Brief description of the drawings]

FIG. 1 is a sectional view taken along a line KK in FIG. 2 of a main part of a stator core of an electric machine according to an embodiment of the present invention.

2 is a partial cross-sectional view showing a stator core of an electric machine according to an example of an embodiment of the present invention at a portion corresponding to a portion Q in FIG. 4;

FIG. 3 is an explanatory diagram for explaining a change of a local heat transfer coefficient value along a refrigerant gas flow direction of a stator core according to the present invention in comparison with a conventional example.

FIG. 4 is a longitudinal sectional view schematically showing a main part of a rotary electric machine of a general example.

5 is a partial cross-sectional view showing a stator core of a conventional electric machine at a portion corresponding to a portion Q in FIG. 4;

6 is a view J of FIG. 5 showing a main part of the stator core shown in FIG. 5;
-J arrow view

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Stator core 2 Duct piece 3 Duct piece piece 42 Iron plate 99 Refrigerant gas

Claims (1)

[Claims] A plurality of thin iron core plates having a plurality of coil slots formed therein for mounting stator coils are laminated, and a ventilation duct for flowing a refrigerant gas in the lamination direction of the iron core plates is provided. In the stator core of the electric machine, the ventilation duct is provided with a plurality of duct pieces arranged along the coil slot arranging direction and the interval in the core plate laminating direction is maintained. Is formed along the flow of the refrigerant gas, and is formed by a plurality of duct piece pieces having a lengthwise dimension that divides a linear distance from the refrigerant gas inlet to the refrigerant gas outlet of the ventilation duct into a plurality. The duct pieces are arranged in a zigzag pattern with respect to the flow of the refrigerant gas.