Static induction machine

Abstract

The present invention provides a stationary induction device in which, when using aluminum wire as the winding, the ends of the winding and the external terminals are connected without the need for welding, brazing, soldering, aluminum crimping, or tough wires. [Solution] A stationary induction device 1 having an iron core and at least one winding, wherein the winding 20 has copper conductor portions 31 at both ends, and an aluminum conductor portion 32 between the pair of copper conductor portions 31, and a cold pressure welding boundary portion 35 is formed by joining the copper conductor portion 31 and the aluminum conductor portion 32 by cold pressure welding.

Description

Technical Field

[0001] The present invention relates to a static induction device.

Background Art

[0002] A static induction device such as a transformer or a reactor includes an iron core and at least one winding. Copper wires have been widely used for windings since early times, but aluminum wires may also be used in some cases. While aluminum has the disadvantage that its electrical conductivity is lower than that of copper (approximately 60% of that of copper), it has the advantages of being less expensive and lighter than copper.

[0003] Conventionally, when an aluminum wire is used as a winding, after the aluminum wire is wound around an insulating cylindrical portion that is formed into a cylindrical shape with an electrical insulator and has an iron core inserted therethrough, the aluminum wire is drawn outward from the insulating cylindrical portion, and the drawn end portion of the aluminum wire is connected to a copper lead wire connected to an external terminal. An external terminal is a terminal for electrically connecting a winding to an external electric wire. In such a connection, the end portion of the aluminum wire serving as the winding and the copper lead wire have been connected by soldering or brazing, or connected using a crimp terminal. However, since this connection is a connection between dissimilar metals, aluminum and copper, the difference in coefficient of thermal expansion causes loosening in the connection portion, which results in the problem that electrical contact degrades and electrical resistance increases.

[0004] To solve this problem, a known technique involves interposing a ToughLead wire between the end of the aluminum winding wire and the copper lead wire connected to the external terminal. The ToughLead wire is a wire formed by joining a short aluminum wire and a short copper wire by cold pressure welding. At the cold pressure welding joint, copper atoms and aluminum atoms are integrated by metallic bonding. The aluminum wire side of the ToughLead wire is connected to the end of the aluminum winding wire by welding or crimp terminals, and the copper wire side of the ToughLead wire is connected to the copper lead wire using crimp terminals. By interposing the ToughLead wire in this way, the parts that would normally be connected by soldering or brazing, or by crimp terminals, become connections between the same type of metal, thus solving the above problem caused by differences in thermal expansion coefficients.

[0005] However, when welding the aluminum wire side of a Toughleed wire to the end of the aluminum wire winding, welding aluminum is difficult and requires a high level of skill from the worker. In addition, welding requires qualifications, not just for aluminum, which limits the number of people who can perform the work. Furthermore, preparing for the work, such as taking measures to protect against high-temperature spatter, is time-consuming and laborious.

[0006] Furthermore, when connecting the aluminum wire side of a Toughlead wire to the end of the wound aluminum wire using a crimp terminal, a special crimp terminal is required, resulting in high costs. This is because aluminum has the property of gradually relaxing stress over time when external force is applied, causing the crimping force of a general crimp terminal to decrease over time. In addition, aluminum is very prone to oxidation, requiring a special crimp terminal filled with a material that prevents contact with air. [Overview of the project] [Problems that the invention aims to solve]

[0007] Therefore, in view of the above circumstances, the present invention aims to provide a stationary induction device that, when using aluminum wire as the winding, can connect the end of the winding to the external terminal without using welding, brazing, soldering, aluminum crimping, or tough wire. [Means for solving the problem]

[0008] To solve the above problems, the stationary induction device according to the present invention is "A stationary induction device having an iron core and at least one winding, The winding has copper conductors at both ends, and an aluminum conductor between the pair of copper conductors. The copper conductor portion is directly connected to an external terminal for connecting to an external wire. The copper conductor portion and the aluminum conductor portion at the boundary , by cold pressure welding ru Joining Formed So Furthermore, it has a cold-pressure welded boundary where copper atoms and aluminum atoms are integrated by metallic bonding. "That is the case."

[0009] The stationary induction device according to the present invention, in addition to the above configuration, "The winding consists of a coil portion wound around an insulating cylindrical portion formed in a cylindrical shape from an electrical insulator through which the iron core is inserted, and lead wires extending axially from each end of the coil portion." The aforementioned The cold pressure welding boundary is located in the coil portion, or in the internal lead wire, which is the portion of the lead wire that lies on the circumferential surface of the insulating cylinder portion. dea ru.

[0010] Reference example The stationary guidance equipment will be configured as follows: "The winding consists of a coil portion wound around an insulating cylindrical portion formed in a cylindrical shape from an electrical insulator through which the iron core is inserted, and lead wires extending axially from each end of the coil portion." The cold pressure welding boundary, which is the boundary between the cold-welded copper conductor portion and the aluminum conductor portion, may be located on an external lead wire that is a portion of the lead wire extending outward from an end of the insulating cylinder portion.

[0011] In addition to the above configuration, the static induction device according to the present invention may: comprise a copper tap wire cold-welded to the aluminum conductor portion between the pair of copper conductor portions. Furthermore, the stationary induction device according to the present invention, in addition to the above configuration, The tap wire is inserted into the middle of the aluminum conductor, and the cold pressure welding boundary portion, which is the boundary with the aluminum conductor, is formed at each end of the tap wire. Furthermore, the stationary induction device according to the present invention may be configured as follows: "The tap wires are inserted in pairs into the middle of the aluminum conductor portion." Each of the aforementioned tap wires has a cold-pressure welded boundary portion at only one of its ends, which is the boundary with the aluminum conductor portion, while the other end is a free end. The free ends of each of the pair of tap wires are drawn outward from the end of the insulating cylinder and are electrically connected to each other. Effects of the Invention

[0012] According to the present invention, when an aluminum wire is used as a winding, a static induction device capable of connecting an end of the winding to an external terminal without using a connection portion formed by welding, brazing, or soldering, an aluminum crimp portion, or a Tuffride wire can be provided. Brief Description of the Drawings

[0013] [Figure 1] It is a schematic diagram of a configuration of a static induction device according to a first embodiment of the present invention. [Figure 2] It is a schematic diagram of a configuration of a static induction device according to a second embodiment of the present invention. [Figure 3] It is a schematic diagram of a configuration of a static induction device according to a third embodiment of the present invention. [Figure 4] It is a schematic diagram of a configuration of a static induction device according to a fourth embodiment of the present invention. [Figure 5] It is a schematic diagram of a configuration of a static induction device according to a fifth embodiment of the present invention. [Figure 6] It is a schematic diagram of a configuration of a static induction device as a reference example. [Figure 7]It is an explanatory diagram of means for connecting a copper conductor portion having a larger cross-sectional area than a conventional copper winding to a connector having the same specifications as those of a conventional static induction device.

Mode for Carrying Out the Invention

[0014] Hereinafter, static induction devices 1 to which are embodiments of the present invention 5, and reference example of stationary induction equipment 6 will be specifically described with reference to the drawings.

[0015] First, the static induction device 1 according to the first embodiment will be described with reference to FIG. 1. The static induction device 1 includes an iron core 10, an insulating cylindrical portion 15, and at least one winding 20. The insulating cylindrical portion 15 is formed in a cylindrical shape from an electrical insulator, and the iron core 10 is inserted through the insulating cylindrical portion 15. The winding 20 is wound around and held by the insulating cylindrical portion 15.

[0016] In the single winding 20, both end portions are copper conductor portions 31 respectively, and an aluminum conductor portion 32 is provided between a pair of copper conductor portions 31 (the copper conductor portions 31 on both end portions). The copper conductor portion 31 and the aluminum conductor portion 32 are joined by cold pressure welding. A boundary between the copper conductor portion 31 and the aluminum conductor portion 32 joined by cold pressure welding is a cold pressure welding boundary portion 35.

[0017] Cold pressure welding is a technique for forming metallic bonding by bringing ends of metal materials into contact with each other and applying pressure. On an end surface of a metal material, electrons bonding metal atoms have no bonding partner, so the end surface is in an unstable state (activated state), and therefore easily bonds with oxygen in the air to easily form an oxide film. By bringing the end surfaces of the metal materials into contact with each other, compressing them and causing plastic deformation, the layer having the oxide film is stretched to generate a new surface. By bringing metal atoms present on the new surface closer to each other to a distance of 1 angstrom or less, even dissimilar metals can be metallically bonded to each other.

[0018] Conventionally, when using aluminum for the winding 20 of a static induction device, it was common knowledge among those skilled in the art to use aluminum wire for the entire winding 20. Contrary to this common knowledge, this embodiment has a configuration in which a single winding 20 has a cold-press-welded aluminum conductor section 32 and a copper conductor section 31, and one of its features is that both ends of the winding 20 are made of copper conductor section 31.

[0019] A single winding 20 can be considered as being divided into a coil portion 22, which is the part wound around the insulating cylinder portion 15, and lead wires that extend axially from both ends of the coil portion 22 along the insulating cylinder portion 15. Furthermore, of the lead wires, the portion that lies on the circumferential surface of the insulating cylinder portion 15 is designated as the internal lead wire 21a, and the portion that extends outward from the end of the insulating cylinder portion 15 is designated as the external lead wire 21b.

[0020] The stationary induction device 1 is an example in which the cold pressure welding boundary 35 is located in the coil section 22. Figure 1(a) shows the beginning of the winding 20, showing the case where the winding 20 is drawn in from the outside of the core 10 from above and then wound from the top to the bottom of the core 10. Figure 1(b) shows the end of the winding 20, showing the case where the winding 20 is wound from the bottom to the top of the core 10 and then pulled out to the outside of the core 10 from above.

[0021] In Figure 1(a), only the one-way winding portion is shown, where the winding 20 is drawn in from the outside and above of the core 10 and then wound from the top to the bottom of the core 10. The subsequent winding is not shown. Similarly, in Figure 1(b), only the portion where the winding 20 is pulled out from the outside and above of the core 10 after the one-way winding from the bottom to the top of the core 10 is shown, and the preceding winding is not shown.

[0022] As for the static induction device 1, there are cases where the winding 20 is pulled in from outside the iron core 10, wound from the top to the bottom of the iron core 10, and then wound from the bottom to the top of the iron core 10 in one round trip winding before being pulled out to the outside of the iron core 10, or cases where the winding 20 is pulled in from outside the iron core 10, wound multiple round trip windings before being pulled out to the outside of the iron core 10. Also, in Figures 1(a) and (b), the case where both the starting external lead wire 21b and the ending external lead wire 21b extend upward from the insulating cylinder portion 15 is illustrated, but there are also cases where both extend downward, or where one extends upward and the other extends downward.

[0023] Here, "vertical direction" refers to the direction parallel to the axial direction of the iron core 10. Depending on the orientation in which the static induction equipment is actually used, the "vertical direction" in this document may differ from the "vertical direction" in the real world.

[0024] In the cold pressure welded boundary 35 of the stationary induction device 1, the connected aluminum conductor 32 and copper conductor 31 have approximately the same diameter or width. By positioning the cold pressure welded boundary 35 in the coil section 22, even when a single winding 20 is wound in multiple layers around the insulating cylinder section 15, or when multiple windings 20, such as primary and secondary windings, are wound in staggered positions around the same insulating cylinder section 15, there is an advantage that the area near the boundary between the aluminum conductor 32 and the copper conductor 31 does not bulge or become bulky. If the aluminum conductor 32 and the copper conductor 31 were connected in the coil section 22 by welding, brazing, or soldering, bulging would occur at the connection point due to the overlap of the conductors and the presence of connecting metals or solder. Therefore, when a single winding 20 is wound in multiple layers around the iron core 10, or when multiple windings 20 are wound on the same iron core 10, the bulge at the connection point becomes an obstacle to the winding process, and the finished winding also looks unsightly.

[0025] Similarly, if the aluminum conductor section 32 and the copper conductor section 31 were connected in the coil section 22 using crimp terminals, the connection point would bulge. Therefore, when winding a single winding 20 in multiple layers around the insulating cylinder section 15, or when winding multiple windings 20 in the same insulating cylinder section 15, the bulge at the connection point would hinder the winding process and result in an unsightly appearance of the finished product.

[0026] In contrast, in this embodiment, since the aluminum conductor portion 32 and the copper conductor portion 31 are cold-press-welded, no bulging occurs at the cold-pressure-welded boundary portion 35. Therefore, when a single winding 20 is wound in multiple layers around the insulating cylinder portion 15, or when multiple windings 20 are wound on top of the same insulating cylinder portion 15, even if the winding 20 is wound further on top of the cold-pressure-welded boundary portion 35, the cold-pressure-welded boundary portion 35 does not hinder the winding work of the winding 20, and the outer surface of the coil portion 22 is free of large irregularities when wound, resulting in a good appearance.

[0027] The static induction device 2 of the second embodiment will be described with reference to Figure 2. The static induction device 2 differs from the static induction device 1 of the first embodiment in the position of the cold pressure welding boundary portion 35, but the other components are the same as those of the static induction device 1. Components similar to those of the static induction device 1 are denoted by the same reference numerals, and detailed explanations are omitted.

[0028] In the static induction device 2, the cold pressure welding boundary portion 35 is located on the circumferential surface of the insulating cylinder portion 15, similar to the static induction device 1. However, while the cold pressure welding boundary portion 35 was located on the coil portion 22 in the static induction device 1, in the static induction device 2, the cold pressure welding boundary portion 35 is located on the internal lead wire 21a.

[0029] Figure 2(a) illustrates the starting point of the winding 20. After the winding 20 is drawn onto the circumferential surface of the insulating cylinder 15 from the outside and above, the cold pressure welding boundary 35 is located on the internal lead wire 21a, which is the portion of the winding 20 that extends in a straight line, up to the position where winding begins near the bottom of the insulating cylinder 15. Figure 2(b) illustrates the ending point of the winding 20. From the position where winding of the winding 20 is completed in the coil portion 22 near the bottom of the insulating cylinder 15, until the winding 20 is drawn out to the outside and above of the insulating cylinder 15, the cold pressure welding boundary 35 is located on the internal lead wire 21a, which is the portion of the lead wire that extends in a straight line, and which is on the circumferential surface of the insulating cylinder 15.

[0030] In Figure 2(a), only the portion where the winding 20 is drawn in from the upper outside of the insulating cylinder 15 at the start of winding and wound near the lower part of the insulating cylinder 15 is shown, and the subsequent winding is not illustrated. Similarly, in Figure 2(b), only the portion where the winding 20 is drawn out from the upper outside of the insulating cylinder 15 after being wound near the lower part of the insulating cylinder 15 at the end of winding is shown, and the preceding winding is not illustrated.

[0031] As for the static induction device 2, the state is a combination of Figure 2(a) and Figure 2(b), that is, the winding 20 may be single-layer wound at the lower part of the insulating cylinder 15 and then pulled out upward to the outside of the insulating cylinder 15, or the winding 20 may be multi-layer wound at the lower part of the insulating cylinder 15 and then pulled out upward to the outside of the insulating cylinder 15. Also, Figures 2(a) and (b) illustrate the case where both the starting external lead wire 21b and the ending external lead wire 21b extend upward, but there may also be cases where both extend downward, or where one extends upward and the other extends downward.

[0032] Similar to the static induction device 1, the static induction device 2 also has an aluminum conductor portion 32 and a copper conductor portion 31 joined on the circumferential surface of the insulating cylinder portion 15. However, since the joining of the two is by cold pressure welding, no bulging occurs at the cold pressure welding boundary portion 35. Therefore, when a single winding 20 is wound in multiple layers on the insulating cylinder portion 15, or when multiple windings 20 are wound on the same insulating cylinder portion 15, even if the winding 20 is wound on top of the cold pressure welding boundary portion 35, the cold pressure welding boundary portion 35 does not hinder the winding work, and the outer surface of the coil portion 22 is free of large irregularities when wound, resulting in a good appearance.

[0033] The static induction device 3 of the third embodiment will be described with reference to Figure 3. The static induction device 3 differs from the static induction device 1 of the first embodiment in that it has a tap lead wire 49, and is equivalent to the static induction device 1 with the tap lead wire 49 added. The other components are the same as those of the static induction device 1. Components similar to those of the static induction devices 1 and 2 are denoted by the same reference numerals, and detailed explanations are omitted. Note that Figure 3 shows only the beginning or end side of the winding 20.

[0034] The tap lead wire 49 is made of copper and is connected to the copper conductor section 31 in the coil section 22. This connection can be made by brazing or the like. The tap lead wire 49 is provided to change the number of turns ratio between the primary winding (input winding) and the output windings such as the secondary winding. Therefore, the tap lead wire 49 needs to be connected at a position a certain number of turns away from the end of the winding 20. In this case, the tap lead wire 49 is connected to the copper conductor section 31, which is made of the same metal. Although the static induction device 3 has the disadvantage of having a smaller proportion of the length of the aluminum conductor section 32 in a single winding 20 compared to the static induction device 1 which does not have a tap lead wire 49, it has the advantage of being able to provide the tap lead wire 49 in the same way as conventional transformers.

[0035] Although Figure 3 shows the case where there is one tap lead wire 49, by connecting multiple tap lead wires at positions with different numbers of turns in the copper conductor section 31, the turns ratio can be changed in multiple stages, and the output voltage can be made to differ in multiple stages.

[0036] The fourth embodiment of the static induction device 4 will be described with reference to Figure 4. In static induction devices 1 to 3, the entire length between a pair of copper conductor sections 31 in a single winding 20 was an aluminum conductor section 32. In contrast, static induction device 4 differs in that, in addition to the aluminum conductor section 32, it has a tap wire 41 between the pair of copper conductor sections 31, and the other configurations are the same as those of static induction devices 1 to 3. Also, static induction device 4 is the same as static induction device 3 in that it has a tap lead wire 49. Components the same as those in static induction devices 1 to 3 are denoted by the same reference numerals, and detailed explanations are omitted. Note that Figure 4 shows only the beginning or end side of the winding 20.

[0037] The tap wire 41 is made of copper and is inserted into the middle of the aluminum conductor section 32. Both ends of the tap wire 41 are joined to the aluminum conductor section 32 by cold pressure welding. The tap lead wire 49 is connected to the tap wire 41. This connection can be made by brazing or the like.

[0038] The static induction device 4 has the advantage of being able to increase the ratio of the length of the aluminum conductor section 32 to the length of a single winding 20, because the tap wire 41 for connecting the tap lead wire 49 is provided in the middle of the aluminum conductor section 32, compared to the static induction device 3.

[0039] In Figure 4, a tap wire 41 is inserted in only one location in the aluminum conductor section 32, and consequently, only one tap lead wire 49 is shown. However, by providing multiple tap wires 41 at positions with different turns in the aluminum conductor section 32, and connecting multiple tap lead wires 49 accordingly, the turns ratio can be changed in multiple stages, and the output voltage can be varied in multiple stages.

[0040] The fifth embodiment of the static induction device 5 will be described with reference to Figure 5. In the static induction device 4, the tap lead wire 49 was connected to the tap wire 41, whereas in the static induction device 5, the tap wire 41 acts as the tap lead wire, which is different from the static induction device 4. Components similar to those in the static induction devices 1 to 4 are denoted by the same reference numerals, and detailed explanations are omitted. Note that Figure 5 shows only the beginning or end side of the winding 20.

[0041] In the static induction device 4, both ends of a single tap wire 41 were cold-press-welded to the aluminum conductor section 32. In contrast, in the static induction device 5, a pair of tap wires 41 are inserted at the same position as where a single tap wire 41 was inserted in the static induction device 4. In each tap wire 41, only one end is cold-press-welded to the aluminum conductor section 32, while the other end is a free end. The pair of tap wires 41 are then bent and pulled outward from the end of the insulating cylinder section 15. The pulled-out pair of tap wires 41 are electrically connected by crimping or the like, and function as a single tap lead wire.

[0042] The static induction device 5 has the advantage of being able to increase the ratio of the length of the aluminum conductor portion 32 to the length of a single winding 20, because the tap wire 41, which acts as a tap lead wire, is provided in the middle of the aluminum conductor portion 32, compared to the static induction device 3.

[0043] Furthermore, in static induction device 3, the tap lead wire 49 was brazed to the copper conductor part 31, and in static induction device 4, the tap lead wire 49 was brazed to the tap wire 41, resulting in bulging at the connection point in both cases. In contrast, in static induction device 5, the pair of tap wires 41 that act as tap lead wires are cold-press-welded to the aluminum conductor part 32, which has the advantage of not causing bulging at the connection point.

[0044] Although Figure 5 illustrates the case where a pair of tap wires 41 acting as tap lead wires 49 are inserted in only one location in the aluminum conductor section 32, if multiple pairs of tap wires 41 are inserted in the aluminum conductor section 32 at positions with different turns, the turns ratio can be changed in multiple stages, and the output voltage can be made to differ in multiple stages.

[0045] Reference Examples Not Concerning Embodiments of the Invention The static induction device 6 will be explained using Figure 6. The static induction device 6 differs from the static induction device 1 of the first embodiment in the position of the cold pressure welding boundary portion 35, but the other configurations are the same as those of the static induction device 1. Components with the same configuration as those of the static induction devices 1 to 5 are denoted by the same reference numerals, and detailed explanations are omitted.

[0046] In the static induction device 6, the cold pressure welding boundary 35 is located at the external lead wire 21b. Figure 6(a) shows only the beginning of the winding, and the subsequent windings are omitted. Similarly, Figure 6(b) shows only the end of the winding, and the preceding windings are omitted.

[0047] The static induction device 6 can be a combination of Figure 6(a) and Figure 6(b), meaning that the coil portion 22 of the winding 20 may have one round-trip winding, or it may have multiple round-trip windings. Also, Figures 6(a) and (b) illustrate the case where both the starting external lead wire 21b and the ending external lead wire 21b extend upward, but there may also be cases where both extend downward, or where one extends upward and the other downward.

[0048] In the static induction device 6, since the cold-pressure welding boundary 35 is located on the external lead wire 21b, the proportion of the length of the aluminum conductor portion 32 in a single winding 20 can be increased. Also, because the cold-pressure welding boundary 35 is located on the external lead wire 21b, when forming the lead wires (internal lead wire 21a and external lead wire 21b), the portions that are bent at both ends of the coil portion 22 of the winding 20 are the aluminum conductor portion 32. Since aluminum is softer and easier to bend than copper, it has the advantage of being easier to form lead wires compared to the static induction device 1, which bends the copper conductor portion 31 to form the lead wires.

[0049] As described above, the stationary induction equipment 1 of this embodiment 5, and reference example of stationary induction equipment 6 In this case, both ends of a single winding 20 are copper conductors 31. Therefore, the ends of the winding 20 can be directly connected to external terminals for connecting to external wires. In other words, the ends of the winding 20 and the external terminals can be connected without the need for welding, brazing, soldering, aluminum crimping, or tough wires.

[0050] In static induction devices 1 to 6, a single winding 20 has an aluminum conductor section 32 and a copper conductor section 31. The amount of current flowing through this winding 20 must be the same as if the entire winding were made of copper wire. Since the electrical conductivity of aluminum is lower than that of copper, the cross-sectional area of ​​the aluminum conductor section 32 must be increased in order to achieve the same current. Generally, when cold-press welding dissimilar metal wires, the diameter or width of both metal wires is made the same. Therefore, the winding 20 in static induction devices 1 to 6 has a larger diameter or width compared to a winding that is entirely made of copper wire.

[0051] Consequently, when connecting the copper conductor portion 31, which is the end of the winding 20 of the static induction equipment 1 to 6, with an external terminal and a connector such as a crimp terminal, a larger connector is required than the one used in previous static induction equipment where the entire winding was made of copper wire.

[0052] However, in actual use of static induction equipment, conventional windings are used the above Even if the winding 20 is changed, there is a request to keep the other components of the static induction equipment, including the connectors, the same as the previous specifications.

[0053] To meet such requirements, as shown in Figure 7(a), the cross-sectional area of ​​the copper conductor portion 31 at both ends of the winding 20 of the static induction equipment 1 to 6 is reduced. Specifically, in order to reduce the cross-sectional area of ​​the copper conductor portion 31 (to the same as the cross-sectional area of ​​the aluminum conductor portion 32), the diameter or width of the copper conductor portion 31 (Figure A) is reduced to a diameter or width (Figure B) that corresponds to the cross-sectional area through which a current equivalent to the amount of current flowing through the aluminum conductor portion 32 flows. The diameter or width of the copper conductor portion 31 can be reduced by cutting or crushing the copper wire. Here, if the means shown in Figure 7(a) is adopted for the windings of stationary induction devices 1 to 5, it is an embodiment of the present invention. However, if the means shown in Figure 7(a) is adopted for the winding of stationary induction device 6, it is a reference example and not an embodiment of the present invention.

[0054] Alternatively, to meet the above requirements, as shown in Figure 7(b), the cross-sectional area of ​​the copper conductor portion 31 can remain unchanged, and a short copper wire 51 for connection to an external terminal can be connected to the end of the copper conductor portion 31. The diameter or width of this short copper wire 51 is such that it corresponds to the cross-sectional area through which a current equivalent to the amount of current flowing through the aluminum conductor portion 32 flows (Figure B). The connection between the short copper wire 51 and the copper conductor portion 31 can be made by brazing or the like. Here, in the case where any of the static induction devices 1 to 6 employ the means shown in Figure 7(b) for their windings, this is a reference example and not an embodiment of the present invention.

[0055] Although preferred embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and various improvements and design changes are possible without departing from the spirit of the present invention, as shown below.

[0056] For example, the above example illustrates a case where the position of the cold-pressure welded boundary 35, which is the boundary between the copper conductor portion 31 and the aluminum conductor portion 32, corresponds to the starting and ending portions of the winding. Specifically, in the static induction device 1, the cold-pressure welded boundary 35 is located on the coil portion 22 at both the starting and ending portions. In the static induction device 2, the cold-pressure welded boundary 35 is located on the internal lead wire 21a at both the starting and ending portions. 。

[0057] The stationary induction device is not limited to this configuration, and can have a configuration in which the positions of the cold-pressure welded boundary portion 35 do not correspond at the winding start portion and the winding end portion. For example, the stationary induction device can have a configuration in which the cold-pressure welded boundary portion 35 is located on the coil portion 22 at one of the winding start portion and winding end portions, and on the other, the cold-pressure welded boundary portion 35 is located on the internal lead wire 21a. 。

[0058] Furthermore, in conventional static induction devices, multiple metal wires are wound around an insulating cylinder while aligned, and after being pulled out from both ends of the insulating cylinder, they are electrically connected using crimp terminals or the like, thereby making the multiple metal wires function as a single winding. In the present invention, "a single winding" includes the case in which multiple metal wires function as a single winding in this manner. [Explanation of Symbols]

[0059] 1 Stationary induction equipment 2 Stationary induction equipment 3 Stationary induction equipment 4 Stationary induction equipment 5 Stationary induction equipment 6 Stationary induction equipment 10 Iron Heart 15 Insulating cylinder section 20 windings 21a Internal lead wire (lead wire) 21b External lead wire (lead wire) 22 Coil section 31 Copper conductor section 32 Aluminum conductor section 35 Cold pressure welding boundary 41 Wire for taps 49 Tap lead wire 51 Copper wire

Claims

1. A stationary induction device having an iron core and at least one winding, The winding has copper conductors at both ends, and an aluminum conductor between the pair of copper conductors. The copper conductor portion is directly connected to an external terminal for connecting to an external wire. The boundary between the copper conductor portion and the aluminum conductor portion has a cold pressure bonded boundary portion formed by cold pressure welding, in which copper atoms and aluminum atoms are integrated by metallic bonding, The winding consists of a coil portion wound around an insulating cylinder formed in a cylindrical shape from an electrical insulator through which the iron core is inserted, and lead wires extending from each end of the coil portion in the axial direction of the insulating cylinder. The cold pressure welding boundary is located in the coil portion or in the internal lead wire, which is the portion of the lead wire that lies on the circumferential surface of the insulating cylinder portion. A stationary induction device characterized by the following features.

2. Between the pair of copper conductors, there is a copper tap wire that is cold-press-welded to the aluminum conductor. The stationary induction device according to feature 1.

3. The tapping wire is inserted in the middle of the aluminum conductor, and the cold pressure welding boundary portion, which is the boundary with the aluminum conductor, is formed at each end of the tapping wire. The stationary induction device according to feature 2.

4. The tap wire is inserted in the middle of the aluminum conductor portion, Each of the aforementioned tap wires has a cold-pressure welded boundary portion at only one of its ends, which is the boundary with the aluminum conductor portion, while the other end is a free end. The free ends of each of the pair of tap wires are drawn outward from the end of the insulating cylinder and are electrically connected to each other. The stationary induction device according to feature 2.

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