JP4794330B2 - Transformer and manufacturing method thereof - Google Patents

Description

  The present invention relates to a transformer in which a cooling channel for suppressing heat generation caused by energization is formed of a copper pipe, and a method for manufacturing the transformer.

  The industrial welding machine is configured to perform a predetermined welding operation by attaching an actuator for operating a welding transformer and a welding tip to the tip of a robot arm. A welding robot is desired to be light in weight from the viewpoint of speeding up and improving productivity.

  For example, in the welding transformer described in Patent Document 1, a cooling passage is formed in the secondary winding in order to suppress heat generation due to current application. In order to configure this cooling passage, a secondary winding is formed by casting a pipe for a cooling flow path in a cast material. As the casting material, aluminum is used for weight reduction. The material of the pipe is familiar with the same kind of aluminum as the cast material. However, when the cooling medium is water, a copper pipe having higher corrosion resistance than aluminum is used.

By the way, electric corrosion to the doorway and the boundary portion between the aluminum cast material of the copper pipe is feared to occur, technology patents to prevent electrolytic corrosion by connecting the copper collar on the end of the copper pipe It is disclosed in Document 2 .

  Patent Document 2 relates to a welding gun, in which a copper pipe as a cooling medium passage is spirally arranged in an aluminum motor housing, and a copper collar member is connected to an inlet / outlet of the copper pipe. ing. Copper conduits and copper collars are cast in aluminum. A copper collar is fixed to the inlet and outlet of the copper pipe by brazing before casting. The copper collar has a predetermined thickness.

  The welding gun described in Patent Document 2 is suitable because the housing is efficiently cooled by the cooling channel and can be reduced in size.

JP 2002-343914 A JP 2002-346755 A

  In the transformer in the welding gun described in Patent Document 1, the copper collar is fixed by brazing before the copper pipe is cast into the housing. In general, the melting point of the brazing material is lower than the aluminum melting temperature, and the brazing material may melt during casting, and the yield is not necessarily high. If the brazing filler metal melts during casting of aluminum, the copper collar and copper pipe partly peel and the connection strength with the external hose that supplies coolant decreases, or moisture enters the peeled part and corrodes. There is a concern that will occur.

  The present invention has been made in consideration of such problems, and is a transformer having a secondary winding formed by joining a copper collar to the end of a copper pipe by brazing and casting with an aluminum casting material. An object of the present invention is to provide a transformer and a method for manufacturing the transformer that can prevent melting of the brazing material during the casting process.

  A transformer according to the present invention includes a primary winding formed by winding a conducting wire, a cooling flow path body including a copper pipe and a copper collar as a joint brazed to an end of the copper pipe, and at least the cooling A copper pipe of a flow path body, an aluminum secondary winding in which a brazed portion of the copper pipe is cast, and a core made of a laminated steel plate combined with the primary winding and the secondary winding A coating layer containing at least one of aluminum oxide and zirconium silicate is formed on at least the surface of the brazing part and the copper pipe.

  In the transformer manufacturing method according to the present invention, a cooling channel body is formed by brazing a copper collar as a joint to an end portion of a copper pipe, and at least the brazing portion and the surface of the copper pipe have aluminum oxide and Forming a coating layer containing at least one of zirconium silicate, casting a copper pipe of the cooling channel body and a brazed portion of the copper pipe into aluminum to form a secondary winding, and winding a conductive wire; A transformer is obtained by combining the formed primary winding and the secondary winding with a core made of laminated steel sheets.

  According to the transformer and the method for manufacturing the same according to the present invention, the coating agent becomes a protective film by casting a coating agent having a melting point higher than the aluminum melting temperature on the surfaces of the brazed copper pipe and the copper collar. It is possible to prevent the brazing material from being melted during the process.

  Therefore, the copper collar does not peel from the copper pipe, and the connection strength with the external hose that supplies the coolant is sufficiently high. Further, there is no possibility that moisture enters the peeling portion and corrosion occurs.

  Furthermore, by providing the copper collar, it is possible to prevent electrolytic corrosion from occurring at the connection portion with the external hose that supplies the coolant.

  Hereinafter, a transformer and a method for manufacturing the same according to the present invention will be described with reference to FIGS. The transformer 10 (see FIG. 1) according to the present embodiment is used for, for example, voltage conversion for a spot welding welding gun, and is provided at the tip of the robot arm together with the welding gun.

  As shown in FIGS. 1 and 2, the transformer 10 according to the present embodiment includes a transformer main body 12 and a semiconductor stack 13 provided on the top of the transformer main body 12. Hereinafter, in order to specify the direction, the arrow A1 direction in FIGS. 1 and 3 is specified as the right, and the arrow A2 direction is specified as the left.

  The transformer body 12 includes cut cores 14a and 14b made of laminated steel plates, primary windings 16a and 16b obtained by winding a conducting wire many times, and secondary dielectrics generated by the magnetic force generated by the primary windings 16a and 16b. A winding 18, a pair of input terminals 20 connected to the ends of the primary windings 16 a and 16 b, and a support base 21 are included. The primary windings 16a and 16b and the secondary winding 18 are supported by the support base 21 via the cut cores 14a and 14b.

  Each of the cut cores 14a and 14b has a rectangular frame shape in plan view by attaching two substantially “U” -shaped laminated steel plates in plan view (not shown). The secondary winding 18 is a two-turn coil, and includes a first turn portion 18a, a second turn portion 18b, and a horizontal portion 18c that connects the first turn portion 18a and the second turn portion 18b. Have The right side portions of the first turn portion 18a and the second turn portion 18b are inserted through holes in the square frame of the cut core 14a, and the left side portions are inserted through holes in the square frame of the cut core 14b. Details of the secondary winding 18 will be described later.

  The primary windings 16a and 16b are formed in advance by a predetermined winding machine, and after being combined with the secondary winding 18, are fixed with a predetermined band with the cut cores 14a and 14b interposed therebetween. The primary winding 16a is assembled along the front and back surfaces of the first turn portion 18a of the secondary winding 18, and the primary winding 16b is assembled along the front and back surfaces of the second turn portion 18b. One end portions of the primary winding 16a and the primary winding 16b are connected to the input terminal 20, and the other end portions are connected to each other.

  The semiconductor stack 13 includes four thin semiconductors 22a, 22b, 22c and 22d, cooling fins 24a, 24b, 24c, 24d and 24f sandwiching these semiconductors, and blocks 26a, 26b which connect these cooling fins. 26c. Cooling flow paths 28 are provided in communication with the cooling fins 24a to 24f and the blocks 26a to 26c, respectively. One end on the inlet side of the cooling channel 28 is an inlet port 30a that opens to the side surface of the cooling fin 24a, and the other end on the outlet side is an outlet port 30b that opens to the side surface of the cooling fin 24f. In this semiconductor stack 13, the semiconductors 22a to 22d can be cooled by circulating cooling water in the cooling flow path 28 from the inlet port 30a toward the outlet port 30b.

  As shown in FIG. 3, the secondary winding 18 is a two-turn coil formed by aluminum casting, and has a first turn portion 18a, a second turn portion 18b, and an upper horizontal portion 18c. . The secondary winding 18 is made of an aluminum material itself. The secondary winding 18 is a larger and stronger member than the primary windings 16 a and 16 b and the cut cores 14 a and 14 b, and serves as a base structure of the transformer main body 12. A cooling channel body 60 for circulating cooling water is cast into the secondary winding 18.

  The surface of the secondary winding 18 is subjected to electroless nickel plating, and moisture adheres to a portion where a copper member (for example, the semiconductor stack 13, the cooling fin 24, and the negative electrode) is brought into contact with the surface due to condensation. Even if this is not the case, electrolytic corrosion or the like does not occur.

  The first turn portion 18a includes a square hole 40a through which a part of the cut cores 14a and 14b is inserted at the center, and is a substantially rectangular flat shape in a side view (see FIG. 1). It is chamfered in an arc shape. A thin slit 42a is provided from the upper part of the square hole 40a toward the upper surface of the first turn part 18a, and the first turn part 18a has a substantially C-shape opening upward.

  A slightly projecting terminal block 44a is provided at the left end of the upper surface of the first turn portion 18a. The terminal block 44 a is provided with two screw holes 46 a opened in the left direction in FIG. 1 in parallel, and the terminal 50 a is attached by two screws 48. The connection line of the terminal 50a is connected to a transformer (not shown).

  In the lower part of the surface of the terminal block 44a where the screw hole 46a is provided, an inclined surface 52a is provided that is inclined obliquely downward. An inlet port 60a at one end of the cooling flow path body 60 is opened in the inclined surface 52a.

  The second turn portion 18b has the same shape as that of the first turn portion 18a and is configured to be reversed in the left-right direction, and a detailed description thereof will be omitted. The reference numerals of the respective parts in the second turn part 18b are indicated by adding a subscript “b” in place of the subscript “a” of the reference sign in the first turn part 18a. An outlet port 60b at the other end of the cooling flow path body 60 is opened on the inclined surface 52b of the second turn portion 18b.

  As shown in FIG. 1, the inlet port 60a is connected to the outlet port 30b of the semiconductor stack 13 by the relay hose 100b. The inlet port 30a of the semiconductor stack 13 is connected to the cooling water supply hose 100a. The outlet port 60b is connected to the cooling water drain hose 100c. With such a connection, the cooling water flows in the order of the supply hose 100a, the cooling flow path 28, the relay hose 100b, the cooling flow path body 60, and the drainage hose 100c to cool the semiconductor stack 13 and the transformer main body 12.

  Returning to FIG. 3, the horizontal portion 18 c is a portion that connects the upper right portion of the first turn portion 18 a and the upper left portion of the second turn portion 18 b while being inclined in plan view. The thickness of the horizontal portion 18c is set to be substantially the same as the thickness of the first turn portion 18a and the second turn portion 18b. Two screw holes 54a are provided in the upper right part of the first turn part 18a and in the front part of the horizontal part 18c. Similarly, two screw holes (not shown) are provided in the upper left part of the second turn part 18b and in the back part of the horizontal part 18c. The screw hole 54a is used for fixing the semiconductor stack 13, and a predetermined negative electrode is connected to the screw hole on the back side.

  Next, the cooling flow path body 60 for cooling the secondary winding 18 is demonstrated, referring FIG.4 and FIG.5.

  As shown in FIG. 4, the cooling flow path body 60 includes a copper pipe 62, a copper collar 64 a provided at one end of the copper pipe 62, and a copper collar 64 b provided at the other end. The copper pipe 62 makes one turn around the first turn portion 18a counterclockwise from one end where the copper collar 64a is provided (see FIG. 1), passes through the horizontal portion 18c, and then passes through the second turn portion 18b. To the other end provided with the copper collar 64b (see FIG. 3). The copper pipe 62 is formed in a gently wavy shape so that the path in the secondary winding 18 becomes long from the viewpoint of improving the cooling efficiency.

  The cooling flow path body 60 is cast into the secondary winding 18, one end provided with the copper collar 64a opens into the inclined surface 52a to form the inlet port 60a, and the other provided with the copper collar 64b. The end opens to the inclined surface 52b to form the outlet port 60b.

  As shown in FIG. 5, the copper collar 64a has a short cylindrical shape, and an internal thread 66 is provided on the opening side. The copper collar 64 a has an inner diameter that is substantially equal to the outer diameter of the copper pipe 62, and the insertion-side end portion is brazed while being inserted into one end of the copper pipe 62. The brazing portion 68 is provided over one circumference so as to form a fillet at the contact portion between the insertion side end portion of the copper collar 64 a and the copper pipe 62.

  According to the brazing portion 68, the copper collar 64a can be securely fixed to the copper pipe 62. Although detailed description is omitted, the copper collar 64b at the other end has the same configuration and the same effect.

  As shown in FIG. 5, a coating layer 70 is formed on the surface of the cooling flow path body 60. The coating layer 70 is formed by applying and heating a coating agent at a stage before casting the cooling flow path body 60 into the secondary winding 18. The coating layer 70 is formed on the entire surface of the cooling flow path body 60 including the brazing portion 68.

  The coating agent is heat resistant, and for example, a coating containing at least one of aluminum oxide and zirconium silicate may be used. Aluminum oxide has a high melting point of 2020 ° C., and has the effect of improving surface strength and thermal shock resistance. Zirconium silicate has a high melting point of 2550 ° C. Zirconium silicate has a high corrosion resistance and does not react with most chemical substances, and can prevent reaction between molten aluminum and silver solder or copper. Although copper has a property of reacting with aluminum, erosion can be prevented by providing a coating layer 70 containing zirconium silicate or the like.

  According to these coating layers 70, even when they are in contact with the molten aluminum, they do not dissolve, so that they become a barrier on the surface of the cooling flow path body 60 and can protect the inside.

  In addition to this, the coating agent may contain, for example, sodium silicate or magnesium oxide. Sodium silicate is used as a surfactant, and can smooth the surface like soap and improve the flow of molten metal to suppress the generation of voids on the surface. Magnesium oxide is used as a thermal conductivity imparting agent and can improve heat dissipation from a copper pipe. In the secondary winding 18, the cooling water is allowed to flow through the cooling flow path body 60 to transmit the heat generated by the heat resistance of the aluminum to the cooling water to be cooled. Although the performance is lowered, the heat transfer characteristics and the cooling characteristics can be improved by providing the coating layer 70 containing magnesium oxide or the like.

  Next, a method for manufacturing the transformer 10 configured as described above will be described with reference to FIG.

  First, in step S1, a predetermined length is cut out from a copper pipe material, and then bent to form a copper pipe 62.

  In step S2, as shown in FIG. 7, after attaching the copper collars 64a and 64b to both ends of the copper pipe 62, the insertion side ends of the copper collars 64a and 64b are brazed over the entire circumference of the surface of the copper pipe 62. To form the brazed portion 68. The brazing material is, for example, silver brazing and has a melting point of about 600 ° C.

  In step S3, the coating agent is thinly and uniformly applied to the entire surface of the copper pipe 62 and the copper collars 64a and 64b. As described above, the coating agent contains at least one of aluminum oxide and zirconium silicate.

  In step S4, the copper pipe 62 and the copper collars 64a and 64b to which the coating agent is applied are heated by a predetermined means to remove excess moisture and the coating layer 70 is formed. Thereby, the cooling flow path body 60 is obtained.

  In step S5, aluminum casting is performed using a casting mold (not shown) having a cavity in the shape of the secondary winding 18. At this time, the cooling flow path body 60 is disposed in the cavity portion of the casting mold and cast into aluminum to form the secondary winding 18. By the way, the molten aluminum is set at about 740 ° C., for example, and is higher in temperature than the melting point of silver brazing (about 600 ° C.) of the brazing part 68, but the brazing part 68 is made of a high melting point material. Since it is covered with the coating layer 70 containing, it has heat resistance, and the brazing part 68 does not melt. Even if a part of the surface of the brazing portion 68 is melted, the brazing material does not flow out because the coating layer 70 covers the shell.

  Furthermore, by providing the coating layer 70, the hot water flow property on the surface of the copper pipe 62 is improved, the casting is performed smoothly and the formation of nests is suppressed.

  Thereafter, after the aluminum is solidified and cooled, the casting mold is removed, and predetermined screw hole processing is performed to obtain the secondary winding 18.

In step S6, the primary winding 16a and the primary winding 16b formed in advance are attached to the secondary winding 18.

In step S7, fixed by sandwiching the band cut core 14a, and 14b to the assembly of the secondary winding 18 and primary winding 16a, 16b. Further, as described above, one end portions of the primary winding 16a and the primary winding 16b are connected to the input terminal 20, and the other end portions are interconnected. Thereafter, the assembly is attached to the support base 21 to obtain the transformer body 12.

  In step S8, the semiconductor stack 13 is attached to the top of the transformer body 12, and the relay hose 100b is attached. Further, when the transformer main body 12 is used, the supply hose 100a and the drainage hose 100c are attached to supply and circulate cooling water to the cooling flow path 28 and the cooling flow path body 60. Thereby, the semiconductor stack 13 and the transformer main body 12 can be cooled.

  As described above, in the transformer 10 and the manufacturing method thereof according to the present embodiment, the coating layer having the melting point higher than the aluminum melting temperature is applied to the surfaces of the brazed copper pipe 62 and the copper collars 64a and 64b. 70 is provided. The coating layer 70 serves as a protective film and can prevent the brazing material from being melted during the casting process.

  Therefore, the copper collars 64a and 64b do not peel from the copper pipe 62, and the connection strength between the relay hose 100b and the drainage hose 100c for supplying the coolant is sufficiently high. Further, there is no possibility that moisture enters the peeling portion and corrosion occurs.

  Furthermore, female threads 66 are formed on the copper collars 64a and 64b, and the cooling water is in direct contact with the aluminum base material to connect the relay hose 100b and the drainage hose 100c to the copper collars 64a and 64b. It is possible to prevent electric corrosion.

  According to the transformer 10 and the manufacturing method thereof according to the present embodiment, since the secondary winding 18 is mainly formed of aluminum, it is lighter than a secondary winding mainly made of copper. In the case of a secondary winding mainly made of copper, casting is difficult compared to aluminum, and in order to form a cooling water flow path, a pure copper plate is drilled to form a water flow path, which is then soldered. Attach. Such processing has a large number of steps, is difficult to process, and the drill is quickly consumed. On the other hand, according to the transformer 10 and the manufacturing method thereof, the cooling flow path body 60 is cast at the time of casting aluminum, so that the number of processes is small, the processing is easy, and the tools and the like are not consumed.

  The transformer and the method for manufacturing the same according to the present invention are not limited to the above-described embodiments, and it is needless to say that various configurations can be adopted without departing from the gist of the present invention.

It is a front view of the transformer concerning this embodiment. It is a side view of the transformer concerning this embodiment. It is a perspective view of a secondary winding. It is a perspective view of a cooling channel body. It is sectional drawing of the opening part of a cooling flow path. It is a flowchart which shows the procedure of the manufacturing method of the trans | transformer which concerns on this Embodiment. It is a disassembled perspective view of a copper pipe and a copper collar.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Transformer 12 ... Transformer main body 13 ... Semiconductor stack 14a, 14b ... Cut core 16a, 16b ... Primary winding 18 ... Secondary winding 18a, 18b ... Turn part 18c ... Horizontal part 60 ... Cooling flow path body 60a ... Inlet Port 60b ... Exit port 62 ... Copper pipes 64a, 64b ... Copper collar 66 ... Female thread 68 ... Brazing part 70 ... Coating layer 100a ... Supply hose 100b ... Relay hose 100c ... Drain hose

Claims (2)

A primary winding formed by winding a conducting wire;
A cooling flow path body including a copper pipe and a copper collar as a joint brazed to an end of the copper pipe;
At least a copper pipe of the cooling channel body and an aluminum secondary winding in which a brazed portion of the copper pipe is cast,
A core made of a laminated steel sheet combined with the primary winding and the secondary winding;
With
A transformer characterized in that a coating layer containing at least one of aluminum oxide and zirconium silicate is formed on the surface of the brazing part and the copper pipe. A cooling channel body is constructed by brazing a copper collar as a joint to the end of the copper pipe,
Forming a coating layer containing at least one of aluminum oxide and zirconium silicate on the surface of the brazing portion and the copper pipe;
At least a copper pipe of the cooling flow path body and a brazed portion of the copper pipe are cast into aluminum to form a secondary winding,
A method for manufacturing a transformer, characterized in that a transformer is obtained by combining a primary winding formed by winding a conducting wire and the secondary winding with a core made of laminated steel sheets.

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