JPS6114912B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a method for electrically and liquid-tightly connecting the continuous ends of liquid-cooled stator windings in a rotating electric machine.

[Background of the invention]

In so-called direct cooling rotating electric machines where the conductor of the stator winding is made up of a plurality of stacked hollow conductor strands and water passes through them, the ends of the winding conductor are brazed with an intermediate bonding body. The connecting ends of the windings and the intermediate bonding body are brazed and assembled with a suitable brazing gap between them, and the brazing material is melted and bonded by heating from the outside. However, even if we say that the brazing material gap is appropriate, when these parts are combined, the brazing gap will be distorted depending on the dimensional accuracy of each conductor strand and the machining accuracy of the brazing surface of the intermediate joint. A gap larger than the brazing gap is created, or the conductor ends cannot be integrated into the intermediate connection. This problem can be solved if each conductor strand is processed with high dimensional accuracy, but processing a large number of conductor strands with high dimensional accuracy is extremely disadvantageous in terms of cost.

FIG. 2 shows a winding end portion of a rotating electric machine in which a winding conductor is formed by stacking a plurality of such hollow conductor wires in many layers. FIG. 3 is an enlarged view of the brazed joint of FIG. 2;

An intermediate coupling body 9 is provided at an end of a stator winding 6 that protrudes from a stator core 5 of a rotating electrical machine, spanning upper and lower windings 7 and 8. The intermediate coupling body 9 itself is made of a conductive material to electrically connect the upper and lower windings, and is equipped with a cooling water supply/discharge device (not shown) consisting of a pump, a cooler, etc. A flow pipe 10 is provided which is connected to the main body. An intermediate bonding body 9 made of a conductive material and upper and lower winding conductors 11 and 1 each made of a plurality of hollow conductor wires.
2, it is of course necessary to have a good electrical connection, and what is more important is to ensure that even the slightest leakage does not occur at the joint between the two.

As is well known, once a generator or the like is put into operation, the next periodic inspection will be several years later, and the generator will continue to operate during that time. Therefore, even if there is a slight leakage or smearing of the cooling liquid, surrounding dust will adhere to that part and become a current conductor, adversely affecting electrical insulation and eventually leading to major accidents such as short circuits.

In this way, careful attention must be paid to leaks in the cooling channels inside the machine. Therefore,
This type of winding requires very high reliability.
As a result of this detailed experiment conducted to improve reliability, the following findings were discovered.

That is, the upper and lower winding conductors 11, 12, which are made up of a plurality of hollow conductive wires 13, and the intermediate joint body 9 are joined by brazing, but when these parts are combined, there are problems with dimensional accuracy as described above. In addition, the upper and lower windings 7 and 8 are respectively accommodated in the winding grooves 14 of the stator core 5, and have winding conductors 11 and 12 formed by bending in the radial direction at the ends of the windings.
There is a problem in that it is very difficult to insert and assemble into the intermediate joining body 9, which has a small brazing gap on both the upper and lower sides. In other words, when the ends of the winding conductors 11 and 12 are housed in the winding groove 14, they are shifted in the axial direction, radial direction, and circumferential direction, and it is difficult to align them with the intermediate coupling body 9. This is difficult unless the winding wire 6, which is up to 10 meters long, is manufactured with high dimensional accuracy. It is possible to use special jigs and tools to align the conductors at the ends of the windings. However, this is done on a narrow machine and requires a lot of man-hours. Further, in order to easily insert and incorporate such a plurality of winding conductors 11 and 12 into the intermediate joint 9, the following can be considered. That is, the dimensions of the brazing surface of the intermediate joint 9 are increased in advance, and the conductors 11 and 12 are
is inserted, and a third
It is possible to correct irregular conductors by hammering in a metal piece 15 as shown in the figure. However, in this case, the placement braze may become wrinkled or the placement of the placement braze may shift, making it impossible to maintain the appropriate brazing gap necessary for brazing, resulting in an incomplete brazed connection. I get used to it.

An example of the relationship between the brazing gap and the adhesion rate of the brazed part is shown in Figure 4, and as can be seen from this figure,
If the brazing gap is too smaller or larger than the appropriate brazing gap range g, the adhesion rate will drop significantly. If the adhesion rate decreases, minute voids or large unbonded areas will occur on the brazed surface, and water will leak through these areas. Furthermore, the electrical connection is not sufficient, leading to a thermal rise in temperature, which has an adverse effect on the insulation in that area.

[Purpose of the invention]

The present invention has been made in view of this, and its object is to provide a liquid-cooled stator winding end in a rotating electric machine that can be brazed with good reliability without requiring a complicated structure or special equipment. Provides a connection method.

[Summary of the invention]

In order to achieve this object, the present invention includes driving a metal plate coated with a brazing material between at least one side of the connecting end of the stator winding conductor to be connected and the conductive intermediate bonding body. It is characterized by bonding and fixing these by melting the brazing material.

[Embodiments of the invention]

Hereinafter, the present invention will be explained in detail based on illustrated embodiments. FIG. 1 shows a brazed joint at the end of a liquid-cooled stator winding similar to FIG. 3 for explaining an embodiment of the present invention.

Since the ends of the conductors 11 and 12 of the upper and lower windings 7 and 8 each consisting of a plurality of hollow conductor strands 13 are electrically and liquid-tightly connected using the connecting intermediate connector 9 as described above. However, in this embodiment, the dimension in the direction of stacking the hollow conductor strands of the connection hole part, that is, the brazing surface part of the intermediate coupling body 9 is set in advance to be larger than the dimension in the same direction of the upper and lower winding conductors 11 and 12, The ends of the conductors 11 and 12 are inserted into the connection holes of the intermediate coupling body 9, and one side of the gap between the conductors 11 and 12 and the intermediate coupling body 9 in the stacking direction of the hollow conductor strands is The other three sides excepted and the hollow conductor strand 13
With a braze interposed between each row, the metal plate 17 to be soldered is driven into one side where the braze is not interposed, and assembling these together, each hollow conductor element of the upper and lower winding conductors 11 and 12 is inserted. Correct the irregularity of line 13. Thereafter, this joint portion is heated from the outside to melt the brazing material of the plate to be placed and the plate to be soldered, thereby bonding and fixing them together.

As shown in FIG. 5, the brazed metal plate 17 is made by covering both sides of a metal plate 18 with a brazing material 19 to form an integral piece, and various manufacturing methods are conceivable. For example, conditions necessary for bonding on the surface of the metal plate 18 (components, flowability, wettability, etc.)
A method of placing a brazing filler metal 19 with a thickness of several microns to several millimeters and rolling it into a single piece, and dotting a thin plate of the brazing filler metal 19 on the metal plate 18 (by punching, welding, etc.). How to integrate 18 layers of metal plate and 1 brazing material during metallurgy
A method of forming nine layers can be considered.

Incidentally, when the brazing material is heated and melted, it may be inserted from the outside, and when it is inserted in this way, a fillet (brazing edge) is formed at the end of the brazing surface of the intermediate joint 9, Furthermore, it has been confirmed through experiments that the reliability of the joint can be improved.

In addition, in this embodiment, the metal plate 17 to be soldered is
Among the gaps between the intermediate bonding body 17 and the conductors 11 and 12, in the conductor wire stacking direction where large errors are likely to occur (in this direction, errors increase because processing errors of a large number of conductor wires are accumulated). Although it is used only on one side, it can also be used on another side adjacent to this one side, that is, one side perpendicular to the direction in which the conductor strands are laminated, or even on all sides. Of course, the soldering process on the side where the metal plate to be soldered is driven is omitted.

In this method of connecting conductors, the dimensions of the brazing surface of the intermediate joint are set in advance to be larger than the dimensions of the conductor, without paying close attention to the brazing gap between the conductor and the intermediate joint, which requires high precision. This makes it extremely advantageous in terms of cost, as there is no need to increase dimensional accuracy during conductor manufacturing or to increase dimensional accuracy by processing the conductor to obtain an appropriate brazing gap. Become. On the other hand, when each conductor of the upper and lower windings fixed in the winding groove is composed of a stack of multiple hollow conductor wires, such as at the winding end of a rotating electric machine, each of the conductors of the upper and lower windings is Although it is impossible to install it in line with the intermediate coupling body, according to this embodiment, since the intermediate coupling body is used with ample room for insertion of the conductors of the upper and lower windings,
It can be easily inserted and assembled, and then the upper and lower winding conductors can be modified by hammering in the metal plate to be brazed.
Unnecessary voids in the brazed connection can also be eliminated.
In addition, the soldering material of the plate to be brazed works in the same way when it is placed, but since it is adhered to the metal plate as one piece, it does not work as described above when the metal plate is a separate piece. A highly reliable brazed joint structure with no water leakage, with no wrinkles or misalignment of the solder braze, and always with an appropriate brazing gap and high brazing adhesion rate, is achieved. It was done. Moreover, even though such an excellent brazed connection structure can be obtained, compared to conventional connection methods, it does not require complicated work or high-precision machining, and there is no difference in assembly.

Figure 6 shows another example of the metal plate to be soldered.
The metal plate to be brazed has a tapered shape. Such a tapered metal body 20 is advantageous when firmly implanted between the intermediate bonding body and the conductor at the end of the winding of the above-mentioned rotating electric machine. in this case,
The brazed joint of the intermediate joint is connected to the metal body 20 to be brazed.
Of course, it should have a taper angle corresponding to the taper shape.

In addition, FIG. 7 shows the use of two tapered metal bodies 20 shown in FIG. Since there is no need for additional processing, it is advantageous in terms of cost.

〔Effect of the invention〕

As explained above, according to the connection method of the present invention, after the connection ends of the stator winding conductors to be connected are inserted into the connection holes of the conductive intermediate assembly, Since a metal plate is driven and welded between at least one side of the connection end of the stator winding conductor and the conductive intermediate bonding body, the irregularity of each hollow conductor strand at the connection end of the stator winding conductor is corrected. death,
It is possible to braze the connecting end and the conductive intermediate bonding body while always maintaining an appropriate brazing gap between them, without requiring complicated configurations or special equipment. A highly reliable brazed joint of a liquid-cooled stator winding end in a rotating electrical machine with good electrical and liquid-tight connections with high efficiency can be obtained.

[Brief explanation of the drawing]

Fig. 1 is a perspective view showing a brazed joint at the end of a liquid-cooled stator winding for explaining an embodiment of the present invention, and Fig. 2 is a longitudinal cross-section showing the vicinity of the end of a stator winding of a rotating electric machine. 3 is an enlarged perspective view showing the brazed joint portion at the end of the stator winding in FIG. 2, FIG. 4 is a characteristic diagram showing the relationship between the brazing gap and the brazing adhesion rate, and FIG. 5 is a side view. The figure is a perspective view showing one example of the plate to be brazed used in the present invention, and FIGS. 6 and 7 are perspective views showing other examples of the plate to be brazed used in the present invention. 11, 12... Upper and lower winding conductors, 13... Hollow conductor wire, 17... Metal plate to be brazed, 18... Metal plate, 19...
Brazing metal, 20...Tapered metal plate to be brazed.

Claims (1)

[Claims] 1. Each connection end of a stator winding conductor formed by stacking a plurality of hollow conductor wires is inserted into a connection hole of a conductive intermediate bonding body, and placed between them. Welding is performed to electrically connect and liquid-tightly connect the connecting ends of the stator winding conductor, wherein at least one side of the connecting end of the stator winding conductor and the conductive intermediate 1. A method for connecting ends of a liquid-cooled stator winding in a rotating electric machine, which comprises driving a metal plate coated with a brazing material into a bonded body and welding the metal plate. 2. The method of connecting ends of a liquid-cooled stator winding in a rotating electric machine according to claim 1, wherein the metal plate to which the brazing material is applied is formed in a tapered shape.