JP3424450B2 - Method of joining blocks and method of manufacturing coil for rotating electrical machine using the same - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of joining a block body that can be applied to a portion where block-shaped terminals such as a rectangular coil wire end portion through which a large current is passed are vertically and horizontally stacked and collectively joined. In particular, the present invention relates to a joining method suitable for joining ends of a stator coil for a rotating electric machine body used in a turbine generator or a turbine generator.

[0002]

2. Description of the Related Art In rotary electric machines, such as turbine generators, a structure for cooling a coil conductor is adopted as the capacity of the generator alone increases. As a cooling method, a large-capacity generator employs a structure in which the coil conductor is directly cooled. This type of coil conductor
The conductor wire itself has a hollow structure in which cooling holes for supplying a cooling medium are provided. In order to directly supply or discharge the cooling medium to or from the hollow conductor, there is provided a supply / drainage box for electrically energizing the coil conductor and simultaneously supplying and discharging the cooling medium. This liquid supply / drainage box is generally provided at the end of the winding protruding from the iron core of the generator stator for reasons of workability. The supply / drainage box is generally in the shape of a rectangular box.

The connection between the liquid supply / drainage box and the coil conductor is performed by arranging a part of the conductor wire in the liquid supply / drainage box having two open surfaces.
The lid is closed, and finally the liquid supply / drainage box, the lid, and the conductor wire are simultaneously joined by brazing. A part of the conductor wires to be joined is like one in which substantially cubic blocks are vertically and horizontally stacked like the conductor wires 5 in FIG. In this brazing, a brazing material is arranged in advance as shown in FIG. 1 between the conductor wires inside the liquid supply / drainage box, and the whole is heated to melt the brazing material to join them. Further, brazing filler metal of the same type or different types may be supplied from the outside of the liquid supply / drainage box, and brazing may be performed while supplying the brazing filler metal to a portion where the brazing filler metal is insufficient due to gravity flow of the brazing filler metal. Also, brazing is performed while applying a constant load between the lid and the coil during the brazing process.

[0004] Conventionally, phosphorus (P) copper braze which can be brazed in the atmosphere has been used as the brazing material for the brazing. For example, phosphorous copper braze of JIS standard BCuP-1 is used as a brazing material arranged between conductor wires in a thin plate or foil form. The liquidus temperature of this brazing material is 900
° C, solidus temperature is 705 ° C.

[0005]

In the conventional method of arranging and joining a thin plate or foil of a brazing material of a single type between the conductor wires, the following problems have occurred.

When a thin plate or foil of a single type of brazing material is previously arranged above and below the conductor wires for brazing, the temperature of the brazing material becomes higher than the solidus (the temperature at which a liquid phase begins to occur) by heating. The viscosity of the brazing filler metal that has arrived decreases and the gravity of the brazing filler metal itself causes the brazing filler metal to hang down below the conductor wire (below the supply / drainage box). For this reason, the brazing material that penetrates between the conductor wires located on the upper side becomes insufficient, causing defects. In particular, the brazing material in the upper direction (lid side) of the drainage box is insufficient, and many defects are likely to occur in the upper direction. In particular, when the conductor wires of the water supply / drainage box of the rotating machine are joined, corrosion during operation is also added, which causes the exfoliation of the brazing part, which causes insulation deterioration of the coil conductor, causing a major accident of the rotating machine. Becomes a factor.

For a structure in which the cooling medium flows in the center of the conductor wire, the brazing material in the upper direction (lid side) of the drainage box hangs down and the brazing material on the lower side Will increase.
For this reason, this brazing filler metal penetrates into the cooling holes of the coil conductor, and the cooling holes become thin, which causes a decrease in the cooling efficiency of the coil conductor.

An object of the present invention is to ensure that, when a plurality of substantially rectangular parallelepiped-shaped blocks such as the end portions of conductor strands are lined up vertically and horizontally and collectively bonded, the blocks are uniformly and firmly bonded by a sufficient brazing material. To provide a simple joining method.

Further, a rotating electric body coil is formed in which the end portion of a conductor wire having a hollow portion through which a cooling medium flows is joined without causing leakage of the cooling medium during use and without lowering the cooling efficiency of the coil conductor. It is to provide a manufacturing method.

[0010]

To achieve the above object, according to an aspect of the portion to be bonded according to the present onset Ming two or more rows of blocks is a substantially rectangular parallelepiped shape in the width direction and joined side by side two or more rows in the height direction In the method, a plurality of thin plates made of brazing filler metal having different melting points are arranged in at least a gap in the height direction of the block, the block is heated to melt the brazing filler metal, and the blocks are simultaneously joined. A method for joining block bodies is provided. The blocks to be joined are arranged in the vertical and horizontal directions, a thin plate or foil made of a brazing material is arranged between the blocks, and then the blocks are heated from the outside to melt the brazing material. At this time, when a plurality of brazing filler metals having different melting points are stacked, most of the brazing filler metal having a low liquidus melts and permeates between the conductor wires to generate a bonding force. On the other hand, most of the brazing material having a high liquidus is left as it is, so that the brazing material having a low liquidus is prevented from flowing down to the bottom of the block. Due to their combined action, the blocks can be joined without defects. As a result, when the block is a conductive wire, the electrical resistance of the connection portion is reduced, and energy loss can be reduced. Further, as long as it is a connection portion used for a portion that receives a mechanical force such as vibration or rotation, it is possible to provide a highly reliable joint portion in which the joint portion is not cracked or separated for a long period of time. In the present invention, the term "brazing material" refers to a material other than a so-called brazing material that is commercially available, and at least part of itself melts at the time of heating for bonding, and can bond the materials to be bonded to each other. All are called.

In the present invention, it is preferable that the brazing material having the highest melting point is sandwiched between the brazing materials having a lower melting point than the brazing material in the vertical direction. When multiple thin plates of brazing filler metal with different melting points are stacked and pressure bonded (cladding), the brazing filler metal with the highest melting point is sandwiched from the upper limit direction by the brazing filler metal with the lower melting point Acts as a weir that prevents the brazing material with a low melting point from flowing down. The brazing material having a low melting point spreads to the blocks located above and below the brazing material having a high melting point as a boundary, and the blocks can be reliably joined.

Further, in the above, the difference in melting point between the brazing material having the highest melting point and the brazing material having a lower melting point than the brazing material is 30.
It is more preferable that the temperature is not lower than ° C.

If the difference in melting point is too small, most of the brazing material having a high melting point is also melted when melting the brazing material having a low melting point, and the role of the weir becomes insufficient. If the difference in melting point is 30 ° C. or more, sufficiently strong bonding can be obtained. However, the value of 30 ° C. itself does not have a criticality, and is merely an indication of a preferable range.

In the present invention, it is desirable that the heating temperature for joining is between the liquidus temperature and the solidus temperature of the brazing material having the second lowest melting point after the melting point of the brazing material having the lowest melting point. .

In the present invention, the heating temperature for heating the block body to be joined and melting the brazing filler metal is important.
As a matter of course, if the heating temperature is lower than the solidus line of the brazing filler metal with the lowest melting point (the temperature at which a part of the brazing filler metal begins to melt), joining will not be possible, but on the other hand, the brazing filler metal with the highest melting point If heated above the liquidus of the material (the temperature at which all of the brazing material melts), the above weir-like effect cannot be obtained, and the effect of the present invention cannot be sufficiently obtained. Therefore, in order to obtain the effects of the present invention sufficiently, it is desirable to set the heating temperature as described above.

The liquidus temperature of the brazing material having the highest melting point is 850 ° C. or higher and 1000 ° C. or lower, and the liquidus temperature of the brazing material having the lowest melting point is 640 ° C. or higher and 900 ° C. or lower. Is preferred.

The joint strength of the brazing material is almost proportional to the melting point of the brazing material. Therefore, it is desirable that the liquidus temperature of the brazing material having the lowest melting point is 640 ° C. or higher. However, if the heating temperature for joining is too high, thermal deformation, thermal strain, etc. of the joining block material become a problem, so the liquidus temperature is preferably 900 ° C. or lower. In the same relationship, the melting point of the brazing material with the highest melting point is 850 ° C or higher, 10
It is preferably 00 ° C or lower.

In the present invention, the blocks are arranged in the height direction 3
When joining in rows or more, the liquidus temperature of the brazing filler metal with the lowest melting point among the brazing filler metals joining the upper block has the lowest melting point among the brazing filler metals joining the blocks below it. It is preferably below the liquidus temperature of the material.

When the blocks are stacked and joined in three or more steps, the molten brazing material in the upper step flows to the block in the bottom. On the other hand, the brazing material in the lower stage does not cause a problem in joining even if it does not flow so much. Therefore,
Liquidus temperature of the brazing material in the lower part, preferably higher have how the liquidus temperature of the brazing material in it than the upper. However, in this case, there is no practical problem even if the difference in liquidus temperature is not so large.

In the block joining method as described above, a plurality of conductor wires having hollow portions for flowing the cooling medium are provided.
A method of arranging in the horizontal and vertical directions and collectively joining using brazing material,
A plurality of hollow coil conductor wires are arranged in the groove of the stator core, and the conductor wires are provided with a liquid supply / drainage box joined to the ends of the conductor wires by heat welding, and the conductor wires are directly cooled. It is applicable to the manufacturing method of the rotating electrical machine coil having the above structure.

As the composition of the brazing material, a composition containing phosphorus (P) and copper (Cu) as main components, and optionally a third element added thereto can be used. As a commercially available brazing filler metal component, the composition of the brazing filler metal with the higher liquidus is P 0.5.
It is possible to use, for example, a Cu content of ˜5 wt% and a balance of Cu, and a material to which another element such as silver (Ag) is added.
As for the composition of the brazing filler metal having a lower liquidus, a commercially available brazing filler metal component having a P content of 4 to 6 wt% and a balance of Cu, and a part of which is added with other elements such as silver (Ag). Can be applied. A lead-tin based soft solder (melting point: about 300 ° C.) such as solder may be used for joining the portions that do not require so much strength.

An important point is the relationship between the melting point of the brazing material used and the heating temperature at the time of joining. Further, in the present invention, a plurality of conductor wires arranged in the liquid supply / drainage box can be independently brazed in each step in the vertical direction by the brazing material having a high liquidus wire. Therefore, there is also an advantage that the quality control of the brazing layer is facilitated.

Even if the brazing material having the highest melting point does not melt at the time of heating for joining, the effect of the present invention can be obtained. In that case, the bonding strength is slightly reduced as compared with the case where the brazing material partially melts, but the effect of preventing the brazing material having a low melting point from flowing down is produced. In that case, it has good wettability with a metal having a low melting point,
And a brazing material that causes some kind of chemical or physical reaction (although it is problematic to call an insoluble material a brazing material)
Is desirable.

[0024]

DETAILED DESCRIPTION OF THE INVENTION

(Embodiment 1) FIG. 1 is a perspective view showing a brazing method of a liquid supply / drainage box and a conductor wire. As shown in FIG. 1, the liquid supply / drainage box 1
Has a box shape with two sides open. The metal fitting 2 for supplying and discharging the cooling medium and the coil connecting piece 3 are fixed in advance to the liquid supply / drainage box 1 by welding. Although the inside of the supply / drainage box is visible in FIG. 1, the cooling medium supply / discharge chamber inside the supply / drainage box is hollow, and cooling water is supplied to each conductor wire from this hollow portion. It

Brazing is performed in the following order.
First, the brazing material 6 is arranged at each step in the vertical direction of each conductor element wire 5. A plurality of conductor wires 5 on which the brazing material is arranged are bundled and arranged in the liquid supply / drainage box 1 having two open sides, and finally the lid 7
To place.

An embodiment in which brazing materials having different liquid phase lines are combined and arranged in the vertical direction between the conductor wires, which is one of the present invention, will be specifically described below.

FIG. 2 is a sectional view taken along the line AA of FIG.
The brazing filler metal of the present invention is arranged above and below a to f between the conductor wires in the liquid supply / drainage box 1. FIG. 3 shows the constitution of the brazing material of the present invention. As shown in FIG. 3, a brazing material 5a having a high liquidus
To center, complexing with three sheets to sandwich the lower brazing material 5b and 5c of liquidus than the brazing material on both surfaces thereof. This is used as a pair of brazing materials, and is arranged above and below each conductor wire to be brazed.

In this example, as a brazing material having a high liquidus centered at the center of the composite brazing material, the liquidus temperature of P is 4 wt% and the balance is Cu, and the solidus temperature is 70 ° C.
A 5 ° C. P-Cu brazing material was used. The thickness of this brazing filler metal is 0.2 mm. As a stacking method, thin plates of brazing filler metals having different melting points or clad materials obtained by joining foils by applying pressure from the vertical direction may be used, or foils of different brazing filler metals may be simply stacked and used. It is better to use a clad material
It is preferable because the handleability is improved.

On the other hand, P is 5 as a brazing material having a low liquidus.
P-Ag-Cu having a liquidus temperature of 815 ° C. and a solidus temperature of 640 ° C., in which wt%, Ag is 13 w%, and the balance is Cu.
A brazing material (corresponding to JIS standard BCup-5) was used.
The brazing material has a thickness of 0.6 mm . The composite brazing material in which the brazing materials having different liquidus temperatures are combined is arranged in each of the vertical steps a to f between the conductor wires. Next, supply it to the drainage box 1
Finally, the lid 7 is placed on the liquid supply / drainage box. In the brazing, the liquid supply / drainage box 1 is heated from the outside by high frequency heating. The maximum heating temperature is the solidus temperature ( 640 ° C) and liquidus temperature (815 ° C) of the brazing filler metal with the lower liquidus temperature.
750 ° C., which is about halfway between the temperature and 750 ° C.). In the heating process, the liquid phase temperature was 815 ° C and the solid phase temperature was 640 ° C (P4.5-5.5wt% -Ag14.5-15.
5 wt% -remaining Cu, JIS standard BCuP-5 equivalent) is partially supplied. As a result of non-destructive inspection of the brazed portion brazed by the above method by X-ray CT, the defects in the brazed portion are reduced to 1/3 of the conventional one. The coil for a rotary electric machine manufactured by this brazing method was applied to an AC generator with an output of 500,000 kW. As a result, for many years, there was no water leakage from the coil joint, and the generator could operate stably.

(Embodiment 2) In this embodiment, as a brazing material having a high liquidus centered in the center of the composite brazing material, the liquidus temperature of P is 2 wt% and the balance is Cu, and the liquidus temperature is 980 ° C.
A P-Cu brazing material having a solidus temperature of 705 ° C. was used. The thickness of this brazing material is 0.1 mm.

On the other hand, P is 5.5 wt% -in the brazing material having a low liquidus which is arranged above and below the brazing material having a high liquidus.
The liquidus temperature of Ag10wt% -the balance Cu is 81
A P-Ag-Cu brazing filler metal having a temperature of 0 ° C. and a solidus temperature of 640 ° C. was used.

Similar to the first embodiment, a brazing material having a high liquidus is centered, and a brazing material having a lower liquidus than the brazing material is laminated in a sandwich form on the upper and lower sides of the brazing material to form three composite brazing alloys. Use as material. These are used as a pair of brazing materials and are arranged above and below each copper body wire. Next, a plurality of conductor wires on which the brazing material is arranged are arranged in the liquid supply / drainage box 1, and finally the lid 7 is arranged. The supply / drainage box 1 is externally heated by high-frequency heating up to 720 ° C. and brazed. In addition, in the process of heating,
Liquid phase temperature of 815 ℃ and solid phase temperature of 640 ℃ from outside
(P4.5-5.5wt% -Ag14.5-15.5wt%
-Remaining Cu, JIS standard BCuP-5 equivalent brazing material was partially supplied. The result is a braze of the supply / drainage box without brazing defects. As a result, a coil for a rotating electric machine was obtained that did not leak even after many years of operation. Output of a coil for a rotary electric machine manufactured by this brazing method is 1 million k
It was applied to a W alternator. As a result, over the years,
There was no water leakage from the coil joint, and the generator could be operated stably.

Example 3 In this example, a copper foil having a melting point of 1083 ° C. was used as the brazing material having a high liquidus line, which was placed in the center of the composite brazing material. The thickness is 0.2 mm.

On the other hand, as a brazing material having a low liquidus which is disposed above and below the brazing material having a high liquidus, the liquidus temperature of P is 5.0 wt% and the balance Cu is 900 ° C., and the solidus temperature is 6
A P-Cu (corresponding to JIS standard BCuP-1) brazing material at 45 ° C. was used. The thickness of this brazing filler metal is 0.6 mm.

As described above, a brazing material having a lower liquidus than the above brazing material is sandwiched in the center of the brazing material having a high liquidus to form three composite brazing materials. These are used as a pair of brazing materials and are arranged above and below each conductor wire. Next, a plurality of conductor wires on which the brazing material is arranged are arranged in the liquid supply / drainage box, and finally the lid is arranged. This supply / drainage box is heated from the outside by high frequency heating up to a maximum of 820 ° C. and brazed. During the heating process, the liquid phase temperature was 815 ° C and the solid phase temperature was 640 ° C (P4.5 to 5.5) from the outside of the supply / drainage box.
wt% -Ag 14.5 to 15.5 wt% -remaining Cu, JI
Part of the brazing material of S standard BCuP-5) was supplied. The result is a braze of the supply / drainage box without brazing defects. As a result, a coil for a rotating electric machine was obtained that did not leak even after many years of operation. The coil for a rotary electric machine manufactured by this brazing method was applied to an AC generator with an output of 1 million kW. As a result, for many years, there was no water leakage from the coil joint, and the generator could operate stably. Further, it is possible to avoid the worst situation of the generator due to leakage of water.

(Embodiment 4) In Embodiment 4, an embodiment in which brazing materials having different liquidus lines are arranged in the vertical direction between the conductor wires inside the liquid supply / drainage box 1 for brazing will be described. That is,
A brazing material having a high liquidus temperature is arranged on the upper side (lid side) between the conductor wires a to f shown in FIG. 2, and a brazing material having a low liquidus temperature is arranged on the lower side of c to f. Braze. In the present embodiment, the liquidus temperature is 900 on the upper side (cover side) between the conductor wires a to b.
℃ of JIS standard BCuP-1 equivalent, the liquidus temperature of 820 ℃ is equivalent to JIS standard BCuP-5 in the middle of c to d, and below e to f the liquidus temperature of 750 ℃. The JIS standard BCUp-4 equivalent was placed and brazed.

After this is placed in the liquid supply / drainage box 1, a lid 74 is placed and this is heated to a maximum of 780 ° C. by high frequency heating and brazed. In the heating process, the brazing filler metal similar to that of the first embodiment is partially supplied from the outside of the liquid supply / drainage box. The coil for a rotary electric machine manufactured by this brazing method was applied to an AC generator with an output of 1,000,000 kW. As a result, there was no water leakage from the coil joint, and the generator could be operated stably for many years.

[0038]

According to the present invention, blocks can be joined without any defect. As a result, when the block is a conductive wire, the electrical resistance of the connection portion is reduced, and energy loss can be reduced. Further, as long as it is a connection portion used for a portion that receives a mechanical force such as vibration or rotation, it is possible to provide a highly reliable joint portion in which the joint portion is not cracked or separated for a long period of time.

Further, since the defects of the brazing part are reduced and a coil for a rotary electric machine having a highly reliable brazing part can be obtained, the rotary electric machine using this coil can be used even for a long period of time. There is no water leakage from the brazed part. Therefore, it is possible to avoid the electric leakage and stoppage of the generator due to water leakage and the worst situation, and it is possible to perform efficient power generation operation.

[Brief description of drawings]

FIG. 1 is a structure of a joint portion between a liquid supply / drainage box of the present invention and a coil conductor element wire.

FIG. 2 shows a cross section of FIG. 1 showing an embodiment of the invention.

FIG. 3 is a diagram showing a state in which brazing filler metals having different melting points according to the present invention are joined in three layers.

[Explanation of symbols]

1 ... Supply / drainage box, 2 ... Supply / drain metal fittings, 3 ... Connection piece, 4 ... Inside of the supply / drainage box, 5 ... Conductor wires, 6 ... Brazing material, 7 ... Lid.

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Norihiro Watanabe 3-1, 1-1 Saiwaicho, Hitachi, Ibaraki Hitachi Ltd. Hitachi factory (72) Inventor Yuji Iwaki 3-1-1, Saiwaicho, Hitachi, Ibaraki No. 1 Stock company Hitachi Ltd. In Hitachi factory (56) Reference JP-A 52-39555 (JP, A) JP-A 61-169190 (JP, A) JP-A 9-107646 (JP, A) JP-A 9-28062 (JP, A) Actual development Sho-56-145325 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) H02K 3/22 H02K 3/24 H02K 15/04

Claims (7)

(57) [Claims] 1. A method of joining blocks, wherein a plurality of blocks each having a substantially rectangular parallelepiped shape are arranged side by side in a longitudinal direction and a transverse direction, and a thin plate or foil made of a brazing material having a high melting point is formed from the brazing material. A sandwich type composite brazing filler metal sandwiched between low melting point brazing filler metals is arranged between each step of the blocks arranged in the longitudinal direction, and the composite brazing filler metal is a solid phase wire of the low melting point brazing filler metal. A method of joining blocks, wherein the blocks are joined at the same time by heating to a temperature lower than the liquidus temperature of the brazing material having a higher melting point and a higher melting point. 2. The method for joining block bodies according to claim 1, wherein the block is made of a hollow coil conductor wire having a hollow portion for flowing a cooling medium. 3. The composite brazing filler material according to claim 2, wherein the brazing filler metal having a high melting point is made of P-Cu brazing filler metal and the brazing filler metal having a low melting point is made of P-Ag-Cu brazing filler metal. A characteristic method of joining blocks. 4. The block body according to claim 2, wherein the brazing material having a high melting point is made of Cu foil and the brazing material having a low melting point is P-Cu brazing material among the composite brazing materials. How to join. 5. A plurality of block-shaped hollow coil conductor wires are arranged in a vertical direction and a horizontal direction, their ends are brazed to a supply / drainage box, and a cooling medium is placed in the hollow parts of the conductor wires. In the method for manufacturing a rotary electric machine coil having a structure for supplying, a brazing filler metal for brazing the liquid supply / drainage box and the hollow coil conductor element is a thin plate or foil made of a brazing filler metal having a high melting point. Also a sandwich-shaped composite brazing material sandwiched by brazing materials having a low melting point, the composite brazing material is arranged between the stages of the hollow coil conductor wires stacked vertically,
Among the composite brazing filler metals, the melting point is higher than the solid phase wire temperature of the brazing filler metal having a low melting point and is heated to a temperature lower than the liquidus temperature of the brazing filler metal having a high melting point, and a plurality of the hollow coil conductor wires are provided. A method of manufacturing a rotating electric machine coil, comprising jointing the supply / drainage box together. 6. The brazing material having a high melting point in the composite brazing material is made of a P-Cu brazing material, and the brazing material having a low melting point is made of a P-Ag-Cu brazing material in the composite brazing material. A method of manufacturing a rotating electric machine coil, which is characterized. 7. A rotating electric machine according to claim 5, wherein the brazing material having a high melting point is made of Cu foil and the brazing material having a low melting point is P-Cu brazing material among the composite brazing materials. Body coil manufacturing method.