Method for welding a circuit conductor and a terminal element of a control device

Abstract

Method for welding a circuit conductor (22) and a component consisting of a plurality of connection elements (11) of the same electronic component (10, 10', 10", 10A, 10B, 10C, 10D, 10E, 10F) of a control device by melting and joining using a welding arc (9) from a first electrode (4) of a micromini TIG welder (1), wherein the method comprises: - Applying at least two of the majority of connection elements (11) of the same electronic component (10, 10', 10", 10A, 10B, 10C, 10D, 10E, 10F), including one of the majority of connection elements (11) to be welded and another of the majority of connection elements (11) that is influenced by a flying welding arc (9), to an identical potential by sandwiching the at least two of the majority of connection elements (11) of the same electronic component (10, 10', 10", 10A, 10B, 10C, 10D, 10E, 10F) of the control device together in a ground-clamp clamping device (5, 6, 30) which serves as a second electrode; and - Arc welding of one of the majority of the connection elements (11) to be welded of the same electronic component (10, 10', 10", 10A, 10B, 10C, 10D, 10E, 10F) and of the circuit conductor to be welded (22) while the one of the majority of the connection elements (11) to be welded of the same electronic component (10, 10', 10", 10A, 10B, 10C, 10D, 10E, 10F) and of the circuit conductor to be welded (22) are grounded.

Description

Background of the invention

[0001] The invention relates to a method for welding a circuit conductor and a terminal element of a control device having a plurality of terminal elements by melting and joining by a welding arc.

[0002] US patent application US 2008 / 0 102 716 A1 (corresponding to Japanese patent application JP 2008-110 357 A) discloses a welding method for welding a terminal of an FET (field-effect transistor) and a bus bar, which is a circuit conductor used in an EPS (electric power steering) control unit, by resistance welding. That is, generally, the FET in the EPS control unit is soldered to a glass epoxy substrate (glass epoxy board), or the FET is soldered to a metal substrate (metal board). Furthermore, generally, a protrusion is provided on the terminal of the FET, and the FET is connected to the bus bar, etc., by resistance welding. In arc welding, excessive current flows during welding, and the excessive current may damage the electronic component. Consequently, arc welding is rarely used.

[0003] DE 44 32 191 C1 describes a method for welding component terminals to the contacts of a printed circuit board and an assembly manufactured using this method. To contact the high-current connection elements of a component, in particular a relay, with connecting conductors of an insulating carrier, the flat plugs of the component are welded in the form of connecting tabs to bent connecting lugs of the connecting conductors embedded in a carrier, e.g., a printed circuit board. To protect the nearby plastic from damage caused by the welding energy, the end sections of the connecting lugs and the connecting tabs are provided with a toothed contour so that the individual teeth are welded one after the other. This allows the teeth to quickly reach the melting phase without the adjacent plastic being melted by heat conduction during the short welding time.

[0004] DE 22 43 890 A shows a device for producing heat- and vibration-resistant, electrically conductive welded joints on connecting wires of electronic components, in particular on diodes and transistors for automotive electronics, wherein the connecting wires included in the welded joint are fixed during the welding process and the area surrounding the welded joint is shielded from the welding arc during the welding process.

[0005] DE 22 13 388 C3 discloses a method for producing heat- and vibration-resistant, electrically conductive connections on connecting wires of electronic components, in particular on diodes and transistors for automotive electronics, wherein a welding process is used. Summary of the invention

[0006] To fix other high-current components of the EPS control unit, etc., a micro TIG spot welder (micro mini TIG welder) is often used. However, when welding the FET terminals and circuit leads, the arc may fly to the area between the terminals, causing damage to the component due to a voltage exceeding the withstand voltage or a peak current (overcurrent). Therefore, the conventional method makes it difficult to use the micro TIG spot welder on a small, vehicle-mounted control device.

[0007] It is therefore an object of the present invention to provide a method for welding a terminal element of an electronic component and a circuit conductor, which is developed to solve the above-mentioned problem and to weld the terminal element of the electronic component, such as an FET, and the circuit conductor, such as the bus bar, by a micro-mini TIG welder to prevent damage to the electronic component and to weld conveniently and reliably at a low cost.

[0008] This object is achieved by the features of claims 1 and 2. The subclaims disclose preferred developments of the invention.

[0009] A method of the technical background of the present invention relates to welding a circuit conductor and a plurality of terminals of an electronic component of a control device by melting and joining them using a welding arc from a first electrode of a micro mini TIG welder, and comprises: using the electronic component having the spaced-apart orspaced-apart terminal elements; and arc welding, while only one of the plurality of terminal elements of the electronic component of the control device to be welded and the circuit conductor to be welded are sandwiched by a ground clamp jig serving as a second electrode, so that one of the plurality of terminal elements of the electronic component of the control device to be welded and the circuit conductor to be welded are grounded.

[0010] According to the present invention, there is provided a method for welding a circuit conductor and a plurality of terminal elements of an electronic component of a control device by melting and joining them using a welding arc from a first electrode of a micro-mini TIG welder, the method comprising the steps of: applying at least two of the plurality of terminal elements of the same electronic component that includes the one of the plurality of terminal elements to be welded and another of the plurality of terminal elements that is affected by a flying of the arc to an identical potential by sandwiching the at least two of the plurality of terminal elements of the same electronic component of the control device with a ground clamp jig serving as a second electrode;and arc welding the one of the plurality of terminal elements of the same electronic component to be welded and the circuit conductor to be welded while the one of the plurality of terminal elements of the same electronic component to be welded and the circuit conductor to be welded are grounded;

[0011] According to another aspect of the invention, there is provided a method for welding a circuit conductor and a plurality of terminals of an electronic component of a control device by melting and joining them using a welding arc from a first electrode of a micro-mini TIG welder, the method comprising the steps of: using the same electronic component having the terminals spaced apart from each other;Applying at least two of the plurality of terminal elements of the same electronic component, which includes the one of the plurality of terminal elements to be welded, and another of the plurality of terminal elements that is affected by a flying arc, to an identical potential by sandwiching the at least two of the plurality of terminal elements of the same electronic component with a ground clamp jig that serves as a second electrode; and arc welding the one of the plurality of terminal elements of the same electronic component to be welded and the circuit conductor to be welded, while the one of the plurality of terminal elements of the same electronic component to be welded and the circuit conductor to be welded are grounded. Short description of the drawings

[0012] Further details, features and advantages of the invention will become apparent from the following description of embodiments with reference to the drawing. It shows: Fig. 1 is an illustrative view showing welding with a micro TIG spot welder according to a first embodiment of the present invention; Fig. 2 is an illustrative view showing welding with a micro TIG spot welder according to a second embodiment of the present invention; Fig. 3 is an illustrative view in which the welding arc is small in the micro TIG spot welder according to the second embodiment of the present invention; Fig. 4 is a perspective view showing an electronic component suitable for the micro TIG spot welder according to the second embodiment; Fig. 5 is a perspective view showing another electronic component suitable for the micro TIG spot welder according to the second embodiment; Fig. 6A is a perspective view showing a control device applied to a micro TIG spot welder according to the third embodiment, Fig. 6B is an enlarged perspective view showing a welding portion of the control device; Fig. 7A is a perspective view illustrating a ground clamp jig used in the micro TIG spot welder according to the third embodiment; Fig. 7B is a perspective view illustrating a state in which the clamps of the ground clamp jig are opened; Fig. 8 is a perspective view showing an electronic component used in the micro TIG spot welder according to the third embodiment; Fig. 9 is a perspective view showing another electronic component used in the micro TIG spot welder according to the third embodiment; Fig. 10 is a perspective view illustrating a variation of a ground clamp jig used in the micro TIG spot welder according to the third embodiment; Fig. 11 is an illustrative view showing welding of another member by the micro TIG spot welder according to the third embodiment; Fig. 12 is a perspective view showing another electronic component used in the micro TIG spot welder according to the third embodiment. Fig. 13 is a perspective view showing still another electronic component used in the micro TIG spot welder according to the third embodiment; Fig. 14 is an illustrative view showing welding by a micro TIG spot welder according to a fourth embodiment of the present invention; Fig. 15A - Fig. 15D are illustrative views showing shapes of connecting elements used in the welding of the third embodiment; and Fig. 16 is an illustrative view showing welding by a micro TIG spot welder according to a fifth embodiment of the present invention. Detailed description of the invention

[0013] The FET is designed for high current. Soldering the FET terminal to the glass-epoxy board requires a dedicated heat sink for the FET and a heat dissipation system on the outside or externally as a cold plate (heat sink). This increases the number of components, inspection man-hours, etc., and thus increases costs. Furthermore, the maximum allowable current of the glass-epoxy board is low. The durability of the solder is a concern.

[0014] If the FET terminal is attached to the metal board by soldering, the board costs are also high. This increases the number of components, inspection man-hours, and so on. Furthermore, a dedicated assembly line is required for mounting on the metal board, which increases costs. Furthermore, the durability of the solder is a concern.

[0015] Furthermore, when the FET terminal and the bus bar are joined by resistance welding, resistance welding is a welding technique in which heat is generated by the resistance of the welded element (object). The bus bar, which serves as the circuit conductor, is a low-resistance metal (pure copper, KFT, etc.). Resistance welding is problematic when the resistance value of the metal is low. If the FET terminal and the bus bar are made of copper, spot welding is also used for welding. Consequently, the strength of the welded part is unstable during resistance welding. Furthermore, the load on the welder becomes large, and the welding process is problematic.

[0016] Furthermore, if a coating made of a different metal is used to increase the resistance value, the electrical resistance of the bonded area also increases after welding. This causes heat generation during use of the FET, which requires a heat dissipation measure.

[0017] Laser beam welding is also an alternative welding method. The FET terminal and bus bar are made of pure copper. These pure copper terminals, such as the FET terminal and bus bar, absorb the laser light (the laser beam) insufficiently and reflect most of the energy. Therefore, it is necessary to increase the absorption rate by applying a coating. In this case, the coating must be carefully controlled. This consequently increases costs.

[0018] Embodiments of the present invention will be explained below with reference to the drawings.

[0019] Fig. 1 is an illustrative view showing welding by a micro TIG spot welder according to a first embodiment of the present invention.

[0020] As in Fig. As shown in Figure 1, the micro TIG spot welder 1 is a micro mini TIG welder. The micro TIG spot welder 1 melts (fuse) a terminal 11 of an FET (field-effect transistor), an electronic component, and a bus bar 22, a circuit conductor used in an electronic control unit 20, such as an EPS (electric power steering system), through a welding arc 9. The micro TIG spot welder 1 includes a welder main body 2, an electrode (first electrode) 4 of a welding torch connected to a negative terminal of the welder main body 2 via a cable 3, and a ground clamp jig 5 connected to a positive terminal of the welder main body 2 via the cable 3 and serving as an electrode (second electrode) to generate an arc discharge between the electrode 4 and the terminal 11 by clamping the terminal 11.This ground clamp jig 5 serving as a second electrode clamp clamps and sandwiches the terminal element 11 of the FET 10 and the bus bar 22 to be welded to ground the terminal element 11 of the FET 10 and the bus bar 22 to be welded during welding.

[0021] A main body of the FET 10 is formed of a source (not shown), a drain (not shown), a gate (not shown), etc. On the main body of the FET 10, three terminals for the source, drain, and gate protrude upward from a rear side of the main body of the FET 10 and extend in series. The terminals 11 are separated from each other by a distance that prevents the welding arc 9 from leaking to the other terminals 11 that are not being welded.

[0022] The electronic or electrical control unit 20 includes a case body 21 made of synthetic resin and a plurality of bus bars (circuit conductors) 22 which form a circuit pattern on the case body 21 and which are formed by molding to protrude upward.

[0023] Next, a welding between the terminal element 11 of the FET 10 and the bus bar 22 of the electrical or electronic control unit 20 by a welding method using the micro TIG spot welder 1 will be explained.

[0024] As in Fig. As shown in Figure 1, a large FET 10 is used to reduce the influence of the welding arc 9 generated by the first electrode 4 of the micro TIG spot welder 1. In the large FET 10, the terminal elements are separated from each other to prevent the welding arc 9 from leaking to the other terminal elements 11 that are not being welded.

[0025] The FET 10 is inserted from the bottom of the housing body 21 of the electronic control unit 20. One of the terminals 11 of the FET 10 to be welded is subsequently mounted so that one of the terminals 11 abuts the bus bar 22 to be welded and protrudes from the housing body 21.

[0026] Subsequently, an end portion of the terminal 11 of the FET 10 to be welded and a welding portion of an end portion of the bus bar 22 to be welded are melted and connected, while only a base end portion of the terminal 11 of the FET 10 to be welded and a base end portion of the bus bar 22 to be welded are sandwiched by the ground clamp jig 5 to be grounded. In this arc welding, the welding condition suitable for the terminal 11 and the bus bar 22 constituting the welded object (product) is selected. For example, the welding condition is such that a distance between the electrode 4 and the welding portion of the welded object is possibly shortened and the size of the welding arc 9 is reduced by reducing the welding current.Furthermore, since a rise time is provided to gradually increase the welding current, the welding current does not rise abruptly at the start of welding. This makes it possible to prevent the welding arc 9 from flying to the peripheral terminal elements 11, etc., due to a sudden flight of the welding arc 9, and to prevent the joint strength and electrical capacity of the joint area from becoming insufficient due to the generation of a shrinkage cavity.

[0027] After TIG welding is completed, the ground clamp 5 is removed, completing the welding process. This completes the fusion bonding and diffusion bonding of the element, which consists of a single metal material. This makes it possible to create a joint with low electrical resistance and high strength.

[0028] The terminals 11 of the large FET 10 are therefore spaced apart from each other to prevent the welding arc 9 from leaking to the other terminals 11 that are not being welded. For example, when the terminal 11 for the gate is being welded, only one of the terminals 11 to be welded and the bus bar 22 adjacent to one of the terminals 11 are sandwiched by the ground clamp jig 5 to be grounded. Thus, the welding arc 9 does not fly to the terminals 11 for the drain and the source. The leakage of the welding arc 9 does not reach the inside of the FET 10. Consequently, it is possible to prevent the generation of a large voltage difference between the gate and the drain or the source and the damage to an insulating layer in the FET 10.In addition, it is also possible to prevent damage to the FET 10 due to the voltage difference between the other terminal elements if the terminal elements 11 for the drain and the source are welded.

[0029] Furthermore, in a case where the other components of the electronic control unit 20 are assembled by the micro TIG spot welder 1, it is possible to perform the welding between the terminal 11 of the FET 10 and the bus bar 22 by the same micro TIG spot welder 1. Thus, it is possible to reduce the solder, equipment, jig and tooling, operation and control man-hours, etc., thereby reducing costs. Furthermore, it is possible to achieve a large production volume (mass production).

[0030] Fig. 2 is an illustrative view showing welding by a micro TIG spot welder according to a second embodiment of the present invention. Fig. Figure 3 is an illustrative view when a welding arc is small in the micro spot welder.

[0031] This micro TIG spot welder 1' includes a ground clamp fixture 6, which brings all three terminal elements of the FET (the electronic component) 10 to an identical potential (an identical electrical voltage) by clamping all three terminal elements of the FET 10' and which also serves as a second electrode. The micro TIG spot welder 1' is essentially identical in most aspects to the welder of Fig. 1, as shown by the use of the same reference numerals.

[0032] Next, the welding between the terminal 11 of the FET 10' and the bus bar 22 of the electronic control unit 20 by the welding method using the micro TIG spot welder 1' will be explained below.

[0033] The micro TIG spot welder 1' uses the ground clamp jig 6, which connects all terminals 11 of the FET 10' to the same potential, and a small FET 10' in which a distance between the terminals 11 and 11 is small.

[0034] As in Fig. As shown in Figure 2, the FET 10' is inserted from the bottom of the housing unit 21 of the electronic control unit 20. The terminal element 11 of the FET 10' to be welded, which protrudes from the housing unit 21, is attached in contact with the busbar 22 to be welded.

[0035] Next, the base end portions of all terminals 11 of the FET 10' and the base end portion of the bus bar 22 to be welded are sandwiched by the ground clamp jig 6 to be grounded, and then an end portion of the terminal 11 to be welded and a welding portion of an end portion of the bus bar 22 are melted (fused) and joined. In this arc welding, the welding condition suitable for the terminal 11 and the bus bar 22 constituting the welded object (product) is selected. For example, the welding condition is such that a distance between the electrode 4 and the welding portion of the welded object is shortened and the size of the welding arc 9 is reduced by reducing the welding current.Furthermore, by providing a rise time to slowly increase the welding current, the welding current does not rise abruptly at the start of welding. This makes it possible to prevent the welding arc 9 from flying to the peripheral terminal elements 11, etc., due to a sudden flight of the welding arc 9, and to prevent the joint strength and electrical capacity of the joint area from becoming insufficient due to the generation of a shrinkage cavity, etc.

[0036] After the TIG welding is finished, the ground clamping device 6 is then removed, whereupon the welding process is completed.

[0037] As in Fig. As shown in Figure 2, arc welding is performed while the base end portions of all terminals 11 of the FET 10' are sandwiched by the ground clamp jig 6 to be grounded. Thus, even if the welding arc 9 flies to the adjacent terminals 11 of the FET 10' that are not being welded, the electricity or current does not enter the FET 10', so the FET 10' is not damaged.

[0038] Even if the size of the welding arc 9 is reduced by reducing the welding current of the micro TIG spot welder 1', as shown in Fig. 3, all the base end portions of the terminals 11 of the FET 10' are sandwiched by the ground clamp jig 6 to be grounded, and arc welding is performed. With this, all the terminals 11 of the FET 10' are provided with the same potential by the ground clamp jig 6. Consequently, it is possible to reduce the load between the terminals 11 of the FET 10'. Therefore, there is no voltage difference between the terminals 11, and it is possible to prevent damage to the FET 10'.

[0039] The Fig. 2 and Fig. However, the second embodiment shown in Figure 3 is applied to the small FET 10', in which the terminals 11 are spaced apart by a relatively small distance, in contrast to the first embodiment. The welding arc 9 of the micro TIG spot welder 1' can fly to the terminals of the FET 10' that are not welded. The welding degree varies at each terminal, and the weld cannot stabilize. As shown in Fig. 4 and Fig. 5, it is therefore advantageous to use the small FET (small electronic component) 10A and 10B in which the terminal elements 11 are spaced apart from each other by a predetermined distance.

[0040] The Fig. The FET 10A shown in Figure 4 comprises two-side terminal elements 11 that are bent upwards to be directed perpendicularly to a top side of the FET 10A, and a central terminal element 11 that is bent downwards to be directed perpendicularly to a bottom side of the FET 10A. This extends the distance between the welding areas of the terminal elements 11 and 11. Fig. The FET 10B shown in FIG. 5 includes both-side terminals 11 bent downward to be perpendicular to a bottom surface of the FET 10B, and a central terminal 11 bent upward to be perpendicular to a top surface of the FET 10B. This widens the distance between the welding portions of the terminals 11.

[0041] By using the small FETs 10A and 10B, in which the spacing between the terminals 11 is widened, it is possible to prevent the welding arc 9 from flying to the other terminals 11 that are not being welded. Thus, it is possible to suppress the influence of the welding arc 9 flying to the other terminals 11 that are not being welded and reliably prevent damage to the interior of the FETs 10A and 10B by reducing the leakage of the welding arc 9. In a case where the spacing between the terminals 11 is widened to prevent the welding arc 9 from leaking to the other terminals 11 that are not being welded, the only terminal 11 to be welded can be clamped to the ground, as in the case of using the large FET 10.

[0042] In this way, each of the terminals 11 of the FETs 10', 10A, and 10B and the bus bar 22 are connected by the micro TIG spot welder 1'. This makes it possible to increase and stabilize the strength of the welding areas of the terminals 11 and the bus bar 22 for fusion bonding and diffusion bonding. Furthermore, it is possible to reduce the number of components. Furthermore, the micro TIG spot welder 1' can be used to attach other components of the electronic control unit 20. If the micro TIG spot welder 1' is used jointly for the connection of the terminal 11 and the bus bar 22 and the connection of the other welding areas, new equipment solely for welding the terminals 11 of each FET 10', 10A, and 10B and the bus bar 22 is not required.Furthermore, it is possible to reduce solder, equipment, fixtures, and tools, as well as operator and control man-hours, thereby lowering costs. Furthermore, mass production is possible.

[0043] Fig. 6A is a perspective view showing an electronic control unit applied to a micro TIG spot welder according to a third embodiment of the present invention. Fig. 6B is an enlarged perspective view showing a welding portion of the electronic control unit. Fig. Figure 7A is a perspective view showing a ground clamp jig used in the micro TIG spot welder. Fig. 7B is a perspective view showing a state where clamps of the ground clamp jig are opened. Fig. 8 is a perspective view showing an electronic component used in the micro TIG spot welder.

[0044] As in Fig. 6A and Fig. 6B, the micro TIG spot welder 1'' includes a ground clamp jig 30 serving as a second electrode that applies three terminals 11 of an FET (an electrical component) 10C to the same potential by clamping all three terminals 11 of the FET 10C. As shown in Fig. 6A and Fig. 8, this ground clamp jig 30 is applied to a small FET, such as an FET 10C, which includes terminals 11 spaced apart from each other. Specifically, terminals 11 on either side of the FET 10C are bent upward. A central terminal 11 of the FET 10C extends in a direction away from the FET 10C (a direction substantially perpendicular to a direction in which the terminals 11 on either side extend) and is bent upward over most of its length. Thus, the spacing between the terminals 11 and 11 is widened. The terminals 11 have a spacing such that the welding arc 9 does not leak to the terminals 11 that are not being welded. The ground clamp jig 30 is applied to the FET 10C configured in this manner.

[0045] As in Fig. 6A and Fig. 6B and Fig. 7A and Fig. As shown in Fig. 7B, the ground clamp jig 30 includes a frame-shaped jig body 31, cylindrical piston rods 33, 33, and 33, a long clamp 34, and short clamps 35 and 35. The jig body 31 is made of metal. The jig body 31 includes a receiving space 32 formed inside the jig body 31 and having a raised step shape corresponding to the arrangement of the terminal members 11. Each of the cylindrical rods 33, 33, and 33 is made of metal. The cylindrical rods 33, 33, and 33 are slidably supported by circular openings 31a, 31a, and 31a, respectively, formed at the base end portion of the ground clamp jig 30. The long clamp 34 is made of metal. The long clamp 34 is attached to one end of the central piston rod 33.The long clamp 34 reciprocates (in the forward and backward directions) in a central receiving area 32a of the receiving space 32 by a compression coil spring 36. Each of the short clamps 35 and 35 is made of metal. The short clamps 35 and 35 are attached to the ends of the piston rods 33 and 33, respectively. The short clamps 35 and 35 reciprocate (in the forward and backward directions) in receiving areas 32b and 32b on either side of the receiving space 32 by the compression coil springs 36.

[0046] The central terminal 11 of the FET 10 is sandwiched without any gap between an inner wall of the central receiving portion 32a of the ground clamp jig 30 and the end portion 34a of the long terminal 34. The mutual terminals 11 and 11 are sandwiched without any gap between the inner walls of the mutual receiving portions 32b and 32b of the ground clamp jig 30 and the end portions 35a of the mutual short terminals 35 and 35. In this case, the terminals 11 of the FET 10C are sandwiched or clamped between the end portions 34a and 35a of the terminals 34 and 35 and the inner walls of the receiving portions 32a and 32b, respectively, in a state where the terminals 34 and 35 are positioned in the reverse direction against the biasing forces of the compression coil springs 36. The ground clamp jig 30 is configured for the FET.Accordingly, when the ground clamp jig 30 is used for the other components, the shape is varied according to the number of terminals and the arrangement of the terminals of the other components.

[0047] In addition, a Fig. 9 can be used as a small FET in which the terminals 11 are spaced apart from each other. In this FET 10D, each of the both-side terminals 11 includes an arm portion 11b that extends away from the FET 10D in a direction with respect to the center terminal 11 (in a direction substantially perpendicular to a direction in which the center terminal 11 extends) and is bent upward in an L-shape at a major part thereof. Moreover, the center terminal 11 is bent upward from a back surface of the FET 10D to be perpendicular to a top surface of the FET 10D. Thus, a distance between the welding portions of the terminals 11 and 11 is widened.The ground clamp jig 30 is used in a direction (a forward and reverse direction) opposite to the direction in which the ground clamp jig 30 sandwiches the terminals 11 of the FET 10C.

[0048] The following explains in detail the welding between the terminal 11 of the FET 10C and the bus bar 22 of the electronic control unit 20 by the welding method using the micro TIG spot welder 1''.

[0049] The 1" micro TIG spot welder uses the ground clamp jig 30, which brings all terminals 11 of the FET 10C to the same potential by clamping all terminals 11 of the FET 10C. Thus, it is possible to use the small FET 10C, which includes terminals 11 spaced from each other by a relatively small distance.

[0050] As in Fig. 6A and Fig. As shown in Figure 6B, the FET 10C is inserted from the bottom of the housing unit 21 of the electronic control unit 20. One of the terminal elements 11 of the FET 10C to be welded is attached adjacent to one of the bus bars 22 that protrudes from the housing body 21 and is to be welded.

[0051] As in Fig. 6B, each of the bus bars 22, 22, and 22 has a width a that is greater than a width b of the corresponding one of the terminal elements 11. Moreover, a wide side surface of each of the terminal elements 11 and a wide side surface of one of the bus bars 22 are clamped so that the wide side surface of each of the terminal elements 11 and the wide side surface of one of the bus bars 22 contact each other. Further, each of the bus bars 22, 22, and 22 is arranged on a surface of one of the terminal elements 11, 11, and 11 that is opposite to the body (a center) of the FET 10C (on the inside with respect to the terminal element 11). The respective shape and arrangement between the bus bars 22 and the terminal elements 11 produce effects described below.

[0052] 1) The long and short clamps 34 and 35, urged by the compression coil springs 36 of the ground clamp jig 30, exert pressure on the large-width busbars 22. Furthermore, the busbars 22 each press the small-width terminals 11 abutting against the busbars 22 against the inner walls of the receiving portions 32a and 32b. Consequently, the long and short clamps 34 and 35 do not directly press the small-width terminals 11 together. The long and short clamps 34 and 35 press the terminals 11 together via the large-width busbars 22. Even if backlash or misalignment of the pressing direction and the pressing force of the long and short clamps 33 and 35 is caused, they are received in the receiving portions 32a and 32b of the mass clamp jig 30, which are integrally formed and have a relatively high strength.This prevents the connecting elements 11 from becoming misaligned or bent during clamping. Consequently, clamping is possible such that each of the connecting elements 11 is positioned at a substantially central position of the lateral width a of one of the busbars 22.

[0053] 2) Each of the bus bars 22 has a lateral width a that is larger than the lateral width b of one of the terminal members 22. Consequently, it is possible to reduce the electrical resistance value of each of the bus bars 22 and suppress heat generation in the connection area between each of the bus bars 22 and one of the terminal members 11.

[0054] As another embodiment, the central bus bar 22 may be arranged on a surface of the corresponding terminal element 11 that is opposite to the body (center) of the FET 10C (on the inside with respect to the corresponding terminal element 11). The bilateral bus bars 22 may be arranged on surfaces of the corresponding terminal element 11 (on the outside with respect to the corresponding terminal elements 11) that are opposite to the surfaces of the corresponding terminal elements 11 that are opposite to the body of the FET 10C. In this case, the bilateral bus bars 22 and 22 may be wired from the FET 10C side. The central bus bar 22 may be wired from a direction opposite to the FET 10C side.When the lead wire needs to bypass the center bus bar 22, using this structure, it is possible to simplify the wiring of the center bus bar 22 and significantly shorten the length of the lead wire.

[0055] The base end portions of all terminals 11 of the FET 10C and the base end portions of the bus bars 22 to be welded are then sandwiched between the inner walls of the receiving portions 32a and 32b of the jig body 31 of the ground clamp jig 30 and the end portions 34a and 35a of the clamps 34 and 35 to be grounded, and the end portions of the terminals 11 to be welded and the end portions of the bus bars 22 are melted and joined. In this arc welding, the welding condition appropriate for the terminal 11 and the bus bar 22 constituting the welded object (product) is selected. For example, the welding condition is such that a distance between the electrode 4 and the welding portion of the welded object is possibly shortened and the size of the welding arc 9 is reduced by reducing the welding current.Furthermore, by providing a rise time to slowly increase the welding current, the welding current does not rise abruptly at the start of welding. This makes it possible to prevent the welding arc 9 from flying to the peripheral terminal elements 11, etc., due to a sudden flight of the welding arc 9, and to prevent the joint strength and electrical capacity of the joint area from becoming insufficient due to the generation of a shrinkage cavity, etc.

[0056] After the TIG welding is completed, the ground clamp fixture 30 is removed, whereupon the welding process is completed.

[0057] As in Fig. 6A and Fig. As shown in Fig. 6B, arc welding is performed while the base end portions of all terminals 11 of the FET 10C are sandwiched by the ground clamp jig 30 to be grounded. Thus, even if the welding arc 9 flies to the adjacent terminals 11 of the FET 10' that are not being welded, the electricity does not enter the interior of the FET 10C. Consequently, the FET 10C is not damaged. Moreover, even if the size of the welding arc 9 is reduced by reducing the welding current of the micro TIG spot welder 1'', all terminals of the FET 10C are brought to the same potential by the ground clamp jig 30 when performing arc welding, while the base end portions of all terminals of the FET 10C are sandwiched by the ground clamp jig 30.This makes it possible to reduce the load between the terminals 11 of the FET 10. There is no potential difference between the terminals 11 and 11. Consequently, the FET 10 is not damaged.

[0058] By using the small FET 10C, which includes terminals 11 separated from each other by a large distance, it is possible to prevent the welding arc 9 from flying to the terminals 11 that are not being welded. Thus, it is possible to suppress the influence of the welding arc 9 flying to the other terminals 11 that are not being welded. Furthermore, it is possible to prevent damage, etc., to the interior of the FET 10C by reducing the leakage of the welding arc 9.

[0059] Furthermore, the base end portions of all terminal elements 11 of the FET 10 or the base end portions of the bus bars 22 to be welded can be sandwiched without any clearance between the inner walls of the receiving portions 32a and 32b of the jig body 31 of the ground clamp jig 30 and the end portions 34a, 35a of the terminals 34 and 35. This makes it possible to improve the joining accuracy of TIG welding, increase mass production, and reduce costs.

[0060] In addition, a Fig. The ground clamp jig 30' shown in Figure 10, which has a ground clamp protrusion 37, can be used as the ground clamp jig. The ground clamp jig 30' has the ground clamp protrusion 37, and thus, it is possible to easily establish a connection to the ground wire (ground line). The wiring for each connection of the respective ground wire can be provided at the terminal. Fig. The mass clamping device 30' shown in Figure 10 is not the one shown in Fig. 8, used for the small FET 10, which includes the terminal elements 11 with the large pitch dimensions. However, it is possible to weld the terminal elements 11 of the small FET 10C, etc., by varying the positions of the three chambers 35, 35, and 35 as in the Fig. 7A and Fig. 7B shown ground terminal 30.

[0061] In the third embodiment, the FET is used as an electronic component. As in Fig. However, as shown in Figure 11, the third embodiment is also applicable to a 10" capacitor (other element) or an I / C, etc. In this embodiment, all terminals are clamped. However, it is optional to clamp only one terminal, which may cause a problem with a withstand voltage, etc.

[0062] The micro TIG spot welder 1" can also be used to attach the other components of the electronic control unit 20. If the micro TIG spot welder 1" is used for welding the terminals 11 of the FET 10C and the bus bar 22 and for welding the other welding areas together, new equipment for welding only the terminals 11 of the FET 10C and the bus bar 22 becomes unnecessary. Furthermore, it is possible to reduce the solder, equipment, jigs and tools, and operating and inspection man-hours, thereby reducing costs and achieving mass production.

[0063] When the terminal element 11 and the bus bar 22 are welded by the micro TIG spot welder 1'', it is further possible to use small FETs (electronic components) 10E and 10F, each comprising terminal elements 11 which are separated from each other as shown in Fig. 12 and Fig. 13 shown, are spaced apart.

[0064] The Fig. The FET 10E shown in Figure 12 comprises two-sided terminal elements 11 that are bent upwards or downwards to be perpendicular to a top or bottom of the FET 10E, and a central terminal element 11 that is not bent and extends straight from the back of the FET 10E. This extends a distance between the welding areas of the terminal elements 11 and 11. The Fig. The FET 10F shown in FIG. 13 includes both-side terminals 11 that are not bent upward to be perpendicular to the top surface of the FET 10F and that extend straight from the back of the FET 10F, and a central terminal 11 that is bent upward or downward to be perpendicular to a top surface or a bottom surface of the FET 10F. This expands a distance between the welding portions of the terminals 11 and 11. Thus, it is possible to expand the distance between the central terminal 11 and the both-side terminals 11 and 11, and to prevent the welding arc 9 from flying to the adjacent terminals 11 during welding.

[0065] Fig. 14 is an illustrative view showing welding by a micro TIG spot welder according to a fourth embodiment of the present invention.

[0066] In order to reduce the size of the welding arc 9 of the micro TIG spot welder 1, the end portion 11a of the terminal member 11 of the large FET 10, which constitutes the welding portion, has a tapered shape in the fourth embodiment, and the end portion 22a of the bus bar 22 has a tapered shape.

[0067] By using the tapered end portion 11a of the terminal element 11 of the large FET 10 and the tapered end portion 22a of the bus bar 22 as the welding portions, it is possible to suppress the spreading (flying) of the welding arc 9. Thus, it is possible to accurately introduce the welding arc 9 and thereby sufficiently weld even with the small arc ball. Consequently, it is possible to suppress the energy of the micro TIG spot welder 1 and thereby further reduce the influence of heat on the other parts. Consequently, it is possible to sufficiently weld even with the small welding arc 9. Thus, it is possible to reduce the size of the welding arc 9 by reducing the welding energy of the micro TIG spot welder 1 in relation to the Fig. 1. Thus, it is possible to suppress the flying of the welding arc 9 to the other terminals 11 that are not being welded, thereby preventing the influence of the flying of the welding arc 9 to the other terminals that are not being welded. Furthermore, it is possible to prevent damage, etc., to the interior of the large FET 10 by reducing the leakage of the welding arc 9.

[0068] Arc welding using the tapered end portions 11a and 22a of the terminal 11 and the bus bar 22 as the welding portions is particularly effective for the small FET 10' and 10A-10F in which the terminals 11 are spaced apart by a small distance. Consequently, when the terminals 11 of the small FET 10' and 10A-10F and the bus bar 22 are welded, it is possible to obtain the identical effects to those of the second and third embodiments. By using the tapered end portions 11a and 22a of the terminal 11 of the small FET 10' and 10A-10F and the bus bar 22, it is possible to suppress the spreading (flying) of the welding arc 9 and to sufficiently weld with the small welding arc 9.Consequently, it is possible to increase the size of the welding arc 9 by reducing the welding energy of the micro TIG spot welder 1 in relation to the micro TIG spot welder of . Fig. 1. Therefore, it is possible to suppress the flying of the welding arc 9 to the other terminals 11 that are not being welded, to prevent the influence of the welding arc on the other terminals 11 that are not being welded, and to securely prevent damage, etc., to the interior of the small FET 10' and 10A-10F by reducing the flying of the welding arc 9 to the other terminals 11.

[0069] The shapes of the end regions 11a and 22a of the connecting elements 11 and the busbar 22 are not limited to the Fig. 14 shown conical shapes. As shown in Fig. 15A, the connecting element 11 or the busbar 22 may be tapered in its entirety up to a tip or upper end region of the connecting element 11 or the busbar 22. As shown in Fig. 5 10B, the end region may have a raised shape. As shown in Fig. 15C, the end portion may have a semicircular (semi-circular) shape. As shown in Fig. As shown in Figure 15D, the entire end portion can be formed thin (have a narrow width). The ends of the end portions 11a and 22a of the terminal member 11 and the bus bar 22 facing the electrode 4 of the micro TIG spot welder 1 are thus cut to have narrow widths, and consequently, the terminal member 11 and the bus bar 22 are welded by the welding arc 9. Since the end portions 11a and 22a have the narrow widths, it is possible to accurately introduce the welding arc 9. Consequently, even with the small arc ball, it is possible to sufficiently weld to suppress the energy of the micro TIG spot welder 1 and further reduce the heat influence on the other parts.

[0070] In the above-described embodiments, the ground clamp jig has both the ground (grounding) function and the clamping function. However, the terminal element 11, etc., and the bus bar 22 can be welded by an arc using a micro TIG spot welder 1A, which includes a ground plate 7 serving as a ground clamp and a clamp jig 8 independently of each other, as shown in FIG. Fig.16. In this micro TIG spot welder 1A, the ground plate 7 connected to the welder main body 2 by the cable 3 is made of a conductive material. The ground plate 7 brings all the terminals of the welded components to the same potential. All the terminals 11 of the FET 10 are pressed onto the ground plate 7 from above during welding, so that all the terminals 11 of the FET 10 contact the ground plate 7. Furthermore, the clamping jig 8 does not need to be connected to the welder main body 2. This clamping jig 8 can clamp the terminal and bus bar to be welded. In addition, all the terminals or those that are problematic in terms of withstand voltage, etc., can be clamped.

[0071] The second and third embodiments further employ the FET (electronic component) including terminals spaced apart from each other by varying the protrusion positions of the terminals. However, it is optional to ensure the sufficient spacing between the terminals by using other components (e.g., a pin, a metal substrate (a metal board), etc.) in the FET. In summary:

[0072] A method for welding a circuit conductor and one of a plurality of terminal elements 11 of an electronic component of a control device by melting and joining them using a welding arc 9 from a first electrode 4 of a micro-mini TIG welder 1 is provided, the method comprising the steps of: using the electronic component having the terminal elements 11 spaced apart from each other; and arc welding while only one of the plurality of terminal elements 11 of the electronic component of the control device to be welded and the circuit conductor to be welded are sandwiched by a ground clamp jig 5, 6, 30 serving as a second electrode, so that one of the plurality of terminal elements 11 of the electronic component of the control device to be welded and the circuit conductor to be welded are grounded. List of reference symbols 1 micro TIG spot welder 2 Welder main part 3 cables 4 Electrode 5, 6, 30 Ground clamping device 7 Ground plate 9 Welding arc 10, 10', 10", 10A, 10B, 10C, 10D, 10E, 10F FET 11 Connection element 11a End area of ​​the connecting element 11b Arm area 20 electronic control unit 21 Housing body 22 Busbar 31 Clamping device body 31a Circular openings 32 recording room 32a Central recording area 32b Double-sided recording areas 33 piston rods 34 Long clamp 35 Short clamp 35a End area of ​​the long clamp 35b End area of ​​the short clamp 36 compression coil spring a, b Side width

Claims

[1] Method for welding a circuit conductor (22) and one of a plurality of connection elements (11) of a same electronic component (10, 10', 10", 10A, 10B, 10C, 10D, 10E, 10F) of a control device by melting and joining by means of a welding arc (9) from a first electrode (4) of a micromini TIG welder (1), the method comprising: - Applying at least two of the plurality of connection elements (11) of the same electronic component (10, 10', 10", 10A, 10B, 10C, 10D, 10E, 10F), including one of the plurality of connection elements (11) to be welded and another of the plurality of connection elements (11) that is influenced by a flying welding arc (9), to an identical potential, by sandwiching the at least two of the plurality of connection elements (11) of the same electronic component (10, 10', 10", 10A, 10B, 10C, 10D, 10E, 10F) of the control device by a ground clamping device (5, 6, 30) that serves as a second electrode; and - arc welding one of the plurality of connection elements (11) to be welded of the same electronic component (10, 10', 10", 10A, 10B, 10C, 10D, 10E, 10F) and the circuit conductor (22) to be welded, while the one of the plurality of connection elements (11) to be welded of the same electronic component (10, 10', 10", 10A, 10B, 10C, 10D, 10E, 10F) and the circuit conductor (22) to be welded are grounded. [2] Method for welding a circuit conductor (22) and one of a plurality of connection elements (11) of a same electronic component (10, 10', 10", 10A, 10B, 10C, 10D, 10E, 10F) of a control device by melting and joining by means of a welding arc (9) from a first electrode (4) of a micromini TIG welder (1), the method comprising: - using the same electronic component (10, 10', 10", 10A, 10B, 10C, 10D, 10E, 10F) having the connection elements (11) spaced apart from one another; - applying at least two of the plurality of connection elements (11) of the same electronic component (10, 10', 10", 10A, 10B, 10C, 10D, 10E, 10F), including one of the plurality of connection elements (11) to be welded and another of the plurality of connection elements (11) that is influenced by a flying welding arc (9), to an identical potential, by sandwiching the at least two of the plurality of connection elements (11) of the same electronic component (10, 10', 10", 10A, 10B, 10C, 10D, 10E, 10F) by a ground clamping device (5, 6, 30) that serves as a second electrode; and - arc welding one of the plurality of connection elements (11) to be welded of the same electronic component (10, 10', 10", 10A, 10B, 10C, 10D, 10E, 10F) and the circuit conductor (22) to be welded, while the one of the plurality of connection elements (11) to be welded of the same electronic component (10, 10', 10", 10A, 10B, 10C, 10D, 10E, 10F) and the circuit conductor (22) to be welded are grounded. [3] Method according to claim 2, wherein the ground clamping jig (5, 6, 30) includes clamps (34, 35) which respectively clamp the mutually spaced terminal elements (11), and which respectively sandwich the at least two of the plurality of terminal elements (11) of the same electronic component (10, 10', 10", 10A, 10B, 10C, 10D, 10E, 10F), which comprise one of the plurality of terminal elements (11) to be welded and another of the plurality of terminal elements (11) which is influenced by a flying of the welding arc (9) to connect the at least two of the plurality of terminal elements (11) of the same electronic component (10, 10', 10", 10A, 10B, 10C, 10D, 10E, 10F) to the identical potential.

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