JP2571683Y2 - Transformer for resistance welding - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resistance welding transformer used, for example, in a resistance welding machine.
The present invention relates to a joint structure of a connection conductor forming a terminal plate or a loop portion having two or more turns connected to an end of a secondary coil as a terminal.

[0002]

2. Description of the Related Art FIG. 1 shows the internal structure of a conventional type of transformer used in a portable spot welder. FIG. 2 shows a cross section of the laminated structure of the primary coil and the secondary coil. FIG. 3 shows a connection structure of a two-turn loop portion of a conventional secondary coil. FIG. 4 is a plan view of FIG.

In the drawings, a secondary coil 2 used in this type of transformer 1 includes a connecting conductor 3 between two coil ends 2A and 2B each having a conductive member bent into a substantially U-shape. Are connected to form a two-turn coil loop circuit. A cooling water passage 4 is formed inside each of the split coil pieces 2A and 2B, and the cooling water passage 4 communicates with a cooling water passage 5 opened inside the connection conductor 3 to start the secondary coil. The cooling water is supplied from either the port 6 or the port 7 of the coil end and the cooling water flowing in the secondary coil to prevent the temperature of the secondary coil 2 from rising.

A primary coil 8 in which a band-shaped member is wound is stacked inside and outside the secondary coil 2 with an insulator S disposed. An iron core 9 is inserted into a coil conductor in which a primary coil and a secondary coil are stacked. Terminal plates 11 and 12 are connected to the start end and the end end of the secondary coil 2, respectively. The core 9 and the entire coil are covered with a transformer cover 10 except for the terminal plates 11 and 12. Conventionally, when a winding loop of two turns or more of the secondary coil is formed on the terminal side of the transformer, the U-shaped split coil piece 2A and the split coil piece 2B are located between the terminal sides. The connecting conductor 3 is arranged and connected by brazing, soldering or arc welding. In the above case, an example of a structure in which a connection conductor is connected to two split coil pieces and wound around a two-turn coil has been described. However, in the case of a one-turn coil, the connection conductor 3 is not required, and the terminal plate is not required. Only 11 and 12 will be connected.

[0005]

Conventionally, the connecting conductor 3 or each terminal plate 11 is attached to each end of the split coil pieces 2A and 2B.
In the case of joining the joints 12, a fitting groove is formed on the connection conductor and each terminal plate side to combine the coil ends in an uneven shape, and the coil ends are inserted into the fitting grooves to join the joint portions. However, conventionally, the fitting joint portion is rectangular in cross section, so that only small diameter end mills can be used to machine a square groove, so it is necessary to reduce the amount of cutting and reciprocate multiple times. In addition to the time required for processing, it is difficult to obtain a uniform joint gap, especially in the case of joint shapes of rectangular bodies. Problems such as water leakage from the joints occur. Therefore, the secondary coil soldering operation requires a skilled technique and a large number of man-hours for machining the groove of the joint, resulting in an increase in cost.

[0006]

The present invention employs the following technical means as an improvement to solve the above-mentioned problem. In other words, for resistance welding, an insulating material is arranged on a water-cooled secondary coil, a primary coil is stacked, an iron core is arranged on a coil conductor formed by stacking, and each terminal plate is connected to the secondary coil. In the transformer, the cross-sectional shape of the joint part which is connected by fitting the terminal plate and each end of the secondary coil in an uneven shape forms a straight line in which two opposite sides of a quadrilateral are substantially parallel, The main feature is that the remaining two sides are arcs whose diameter is the distance between the straight lines, or that the length of the straight lines is almost zero, that is, circular or similar. Still another is to connect a connecting conductor to a plurality of split coil pieces bent into a substantially U-shape to form at least two coil pieces.
An insulating material is arranged on a water-cooled secondary coil having a winding loop portion having a turn of not less than a turn, and a primary coil is stacked. An iron core is arranged on a coil conductor formed by the stacking. In the resistance welding transformer in which a terminal plate is connected to each of the start end and the end end, the connection conductor and each terminal plate are connected to each end of the split coil piece in an uneven manner. The cross-sectional shape of the joint portion is such that two opposing sides of the quadrilateral form a straight line substantially parallel to each other, and the remaining two sides are arcs whose diameter is the distance between the straight lines, or the length of the straight line is substantially The main feature is that it is zero, that is, circular or similar.

[0007]

According to the structure of the secondary coil according to the present invention, when the two divided coil pieces are connected by the connecting conductor or when the terminal plate is connected to the secondary coil as in the prior art, the fitting between them is performed. By making the joint shape oval, the gap of the joint part becomes uniform, the rolling around is improved, and a fatal accident due to water leakage from the wound loop part or the incomplete connection part in the terminal board is prevented. In addition to being able to drastically eliminate it, it also facilitates the manufacture of secondary coils, and improves transformer durability and reduces costs.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings. FIG. 5 is a front view of the terminal side of the transformer, showing a connection structure of a winding loop portion connected in a front N-shape between two divided coil pieces constituting a secondary coil via a connection conductor. Is shown. FIG. 6 shows an embodiment of the connecting conductor of the present invention. The primary coil, iron core, transformer cover, and the like are basically the same as the structure of the conventional transformer, and the detailed description is omitted.

The secondary coil 2 of the present invention has a two-
This is an example of the case where a loop circuit is formed in which a conductive member is mechanically bent into a substantially U-shape, and divided coil pieces 2A and 2B are connected in a front N shape via a connection conductor 3 to form a loop. -Formed with a loop portion. The split coil piece 2A and the split coil piece 2B are formed by bending a conductive member into a substantially U-shape as in the prior art, and have a cooling water passage 4 formed therein so that cooling water flows through the water hole. is there. Although not shown in the drawings, the split coil pieces 2A and 2B may have cooling pipes connected to the outer peripheral edge.

The split coil pieces 2A and 2B have only the outer shape of the joint end to which other parts are connected, for example, the cross section forms a straight line in which two opposing sides of a quadrilateral are almost parallel, and the remaining two sides are parallel. Press-forming a circular arc whose diameter is the distance between the straight lines and a non-rectangular cross-sectional shape (hereinafter simply referred to as an oval shape) in which the length of the straight line is almost zero, that is, circular or similar; Alternatively, the outer shape of the entire divided coil piece may be formed into the above-mentioned oval cross section from the beginning.
As in the conventional case, when the cross-sectional shape of the entire secondary coil is rectangular, a thin insulating plate S is usually inserted between the primary coil and the secondary coil, but the insulation creepage distance is not sufficient. In some cases, dielectric breakdown may occur when the edge (corner) of the primary coil and the edge (corner) of the secondary coil that are adjacent to each other are close to each other. However, by forming the outer peripheral edges on both sides of the secondary coil into a semicircular shape, the creepage distance of the insulation between the primary coil and the secondary coil can be lengthened. It is also possible to prevent it.

The connection conductor 3 is made of one conductive member and is located on the terminal side of the split coil piece 2A and the split coil piece 2B, and has an end of one split coil piece 2A and an end of the other split coil piece 2B. And a two-turn loop part which is connected in a front N-shape between the two parts. Connection conductor 3
An oval-shaped fitting groove 15 adapted to the cross-sectional shape of the divided coil piece is cut and formed by an end mill in a portion which is fitted into one end of each of the secondary coil 2A and the secondary coil 2B in an uneven shape. . A cooling water passage 5 is provided inside the connection conductor.
A drill hole is drilled from both sides so that cooling water circulates through the cooling water passage 5 and the cooling water passage 4 of the secondary coil 2.

Similarly, an oval fitting groove 17 is formed on the terminal plates 11 and 12 so as to conform to the outer shape of the coil end portion which is in irregular contact with the start end and the end end of the secondary coil. I have. Then, the split coil piece 2A and the split coil piece 2
B is a fitting groove 1 between the connection conductor 3 and each of the terminal plates 11 and 12.
5 and 17, and the entire circumference of the fitting joint is fixed by brazing or the like. In this case, since the joint shape is an oval shape, a uniform joint gap can be easily obtained, and as a result, the rolling around the entire joint portion is improved and a high joint strength can be obtained.

The use form of the resistance welding transformer of the present invention is as follows.
As in the past, this transformer is hung on the ceiling, the spot welding gun is connected with a secondary cable, and a robot or human can freely operate the welding gun to perform welding, or the transformer and the spot welding gun are connected. Welding is performed by holding the robot as a united welding machine. This transformer is also used in a multi-spot welding machine that welds a plurality of locations with one energization.

[0014]

As described above, according to the present invention, at least two turns or more of a winding loop portion are formed by connecting connecting conductors between divided coil pieces in a front N shape. Alternatively, when connecting the output terminal plate to the start and end ends of the secondary coil, respectively, the concave and convex butt joint shape has an oval cross section, so that the connection groove of the connection conductor and the terminal plate is extremely easy to cut. In addition, the joint gap of the concave and convex portions can be made uniform, the perimeter of the roll can be evenly penetrated, and a connection portion with high strength can be obtained. Therefore, it is possible to completely eliminate a conventional fatal defect such as water leakage from an incomplete joint. Thus, the present invention makes it easier to manufacture a secondary coil than conventional ones, and contributes to the improvement of the durability and safety of a resistance welding transformer, and reduces the cost of the transformer by reducing the number of manufacturing steps. Realize.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a structural example of a conventional welding transformer used in a resistance welding machine.

FIG. 2 is an enlarged cross-sectional view of the coil laminated structure taken along the line AA in FIG.

FIG. 3 is a side view showing a structure of a conventional secondary coil.

FIG. 4 is a plan view of a conventional secondary coil.

FIG. 5 is an enlarged front view of a connection conductor connected in a front N shape to a terminal side of a split coil piece constituting a secondary coil according to an embodiment of the present invention.

FIG. 6 is a view showing the structure of the connection conductor of the present invention, wherein FIG. 6A is a front view and FIG. 6B is a side view.

[Explanation of symbols]

 2 Secondary coil 2A Split coil piece 2B Split coil piece 3 Conductive member 4 Cooling water passage 5 Cooling water passage 6 Cooling water passage 8 Primary coil 9 Iron core 11 Terminal plate 12 Terminal plate 15 Fitting groove 17 Fitting groove S Insulator

Claims (2)

(57) [Scope of request for utility model registration] An insulating material is arranged on a water-cooled secondary coil, a primary coil is stacked, an iron core is arranged on a coil conductor formed by the stacking, and each terminal plate is connected to the secondary coil. In the resistance welding transformer, the cross-sectional shape of the joint part which is connected by fitting the terminal plate and each end of the secondary coil into an uneven shape is a straight line in which two opposite sides of a quadrilateral are almost parallel. Wherein the remaining two sides are arcs having a diameter equal to the distance between the straight lines, or the length of the straight lines is substantially zero, that is, circular or similar. vessel. 2. A water-cooled secondary coil in which at least two turns or more are formed by connecting connecting conductors to a plurality of divided coil pieces bent into a substantially U-shape. In a resistance welding transformer in which an object is arranged and a primary coil is stacked, an iron core is arranged on a coil conductor formed by the stacking, and a terminal plate is connected to a start end and an end end of the secondary coil, respectively. The cross-sectional shape of the joint part of the connection conductor and each terminal plate, which is connected to each end of the split coil piece in an uneven manner, is a straight line in which two opposing sides of a quadrilateral are almost parallel. A transformer for resistance welding, wherein the remaining two sides are arcs having a diameter equal to the distance between the straight lines, or the length of the straight lines is substantially zero, that is, circular or similar.