JP2010028930A - Solder joint structure and power supply apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a solder joint structure which sucks molten solder up to a predetermined height. <P>SOLUTION: A good heat collection portion provided at the distal end 23a of the leg terminal 23 of a connection member (bus bar 20A) which is jointed to a substrate by flow soldering collects heat of molten solder in a solder tank well. A heat conduction limiting section (through-holes 23b) provided at positions between the good heat collection portion and the component mounting portion (a large capacity portion) 21 at such a height as the solder is sucked up limits heat conduction from the good heat collection portion to the component mounting portion 21. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a solder connection structure in which a connection member made of a sheet metal or the like used in a location where a large current flows in a switching power supply apparatus or the like is soldered to a substrate. The present invention also relates to a power supply device provided with this solder connection structure.

  Conventionally, in a solder connection structure of a terminal to a printed circuit board, if the soldered portion of the terminal to be soldered to the printed circuit board is formed wide to pass a large current, a fuse connected to the upper end side of the terminal A large thermal stress (thermal stress) is applied to the soldered portion due to heat such as self-heating of electronic parts such as relays and relays, and solder cracks are likely to occur in the soldered portion.

  Thus, for example, in the terminal holding structure disclosed in Patent Document 1 below, the soldering portion of the terminal is divided into two parts to form a pair of soldering portions, and each connection is made at a position facing the pair of soldering portions of the substrate. Each of the holes was formed, and a pair of round terminal insertion holes were formed at positions facing the pair of soldered portions of the land portion. Further, a constricted portion is formed around the land portion between the pair of terminal insertion holes of the land portion.

  According to this structure, it is possible to alleviate solder stress due to heat acting on the soldering portion, and reliably prevent the occurrence of solder cracks.

JP 2002-270263 A

  However, with regard to such a solder connection structure, there is a problem that the melted solder does not suck up to a predetermined height in addition to the problem due to the solder stress. For example, in a connection member such as a bus bar made of sheet metal and carrying a large current, a large-volume portion such as a current supply line or a component mounting portion may be provided continuously to a leg terminal soldered to the substrate. is there. In such a case, the heat of the melted solder in the solder bath may escape from the leg terminal immersed in the solder bath to the large volume portion. As a result, the temperature of the leg terminal does not rise to an appropriate height, and thus the molten solder may not be sucked up to a predetermined height. On the other hand, the structure in which the soldering portion of the terminal is divided into two parts cannot solve the problem.

  The present invention has been made in view of the above, and an object of the present invention is to provide a solder connection structure capable of sucking molten solder to a predetermined height and a power supply device including the solder connection structure.

  In order to solve the above-described problems and achieve the object, the solder connection structure of the present invention is made of a substrate on which a wiring pattern and a through hole are formed, and a material that is mounted on the substrate and has excellent conductivity. A large capacity portion that allows current and a leg terminal that is inserted into the through hole and soldered, and a connecting member that forms at least a part of the current supply line, and the leg terminal of the connecting member is: Heat conduction that suppresses heat conduction to a position where the solder between the good heat collection part and the large volume part should be sucked up is a good heat collection part that collects heat well at the tip immersed in the solder bath A suppression unit is provided.

  The power supply device of the present invention includes an input side circuit to which an input voltage is applied, an output side circuit for supplying an output voltage to a load, and a transformer connected between the input side circuit and the output side circuit. In a power supply device in which a circuit includes an output diode that rectifies a voltage induced in a secondary winding of a transformer, and an output inductor and an output capacitor that smooth the rectified voltage, a wiring pattern and a through hole are formed. Board, mounted on the board, made of material with excellent electrical conductivity, mounted with output diode and component mounting part allowing large current and leg terminal inserted into through hole and soldered A connecting member constituting at least a part of a current supply line between the output diode and the output capacitor, and the leg terminal of the connecting member has a tip portion immersed in the solder bath heated. It is a good heat collecting part that collects well, and a heat conduction suppressing part that suppresses heat conduction is provided at a height where the solder between the good heat collecting part and the component mounting part should be sucked up. Features.

  According to this invention, the good heat collection part provided at the tip of the leg terminal of the connection member collects the heat of the molten solder in the solder bath well. In addition, the heat conduction suppression unit provided at a height at which the solder between the good heat collection unit and the component mounting unit (large volume unit) should be sucked up from the good heat collection unit to the component mounting unit (large volume) The heat conduction toward the part) is suppressed.

  According to the present invention, the good heat collecting part collects the heat of the melted solder well, and the heat conduction suppressing part suppresses the conduction of heat to the component mounting part (large volume part). In addition, the temperature is raised and the temperature is higher than that of the conventional one. Thereby, after melt | dissolving the solder in a solder tank adheres to the front-end | tip part of a leg part terminal, there exists an effect of sucking up quickly to the position of the appropriate height which should be sucked up from there.

  Embodiments of a solder connection structure and a power supply device according to the present invention will be described below in detail with reference to the drawings. Note that although a switching power supply device will be described as an example of an embodiment of the power supply device, the present invention is not limited to this embodiment.

Embodiment 1 FIG.
FIG. 1 is a circuit diagram of a switching power supply as an embodiment of a power supply according to the present invention. In FIG. 1, a switching power supply apparatus 100 includes a transformer 3 that electrically insulates an input side (primary side) and an output side (secondary side), an input side circuit 4 connected to the input side of the transformer 3, The output side circuit 5 is cut off on the output side of the transformer 3. An AC power supply 1 is applied to the input terminal 2 of the input side circuit 4. The transformer 3, the input side circuit 4, and the output side circuit 5 transmit power from the input terminal 2 to the output terminal 6.

  The input side circuit 4 includes a filter circuit for noise removal, an input circuit 8 including an inrush current prevention circuit, an input side rectifier circuit 10 formed by bridge-connecting a plurality of rectifier diodes 9A to 9D, and an input voltage. The booster circuit 11 outputs a higher DC voltage and the half-bridge inverter circuit 14 including a pair of switch elements 12A and 12B and a pair of capacitors 13A and 13B.

  The output side circuit 5 includes output diodes 15 and 16 that rectify a voltage induced in the secondary winding of the transformer 3, a smoothing output inductor 17, and output capacitors 18 and 19. The output diode 15 includes N diode elements 15 </ b> A to 15 </ b> N connected in parallel, and all of these anodes are connected to one end (dot side terminal) of the secondary winding of the transformer 3. The other output diode 16 is composed of N diode elements 16A to 16N connected in parallel, and the anodes thereof are all connected to the other end (non-dot side terminal) of the secondary winding of the transformer 3. ing. The number of the diode elements 15A to 15N and 16A to 16N may be one or more, and may be appropriately determined in consideration of the secondary side current and the like. One end of the output inductor 17 is connected to the center tap of the output side winding of the transformer 3. As described above, the output diodes 15 and 16 and the output inductor 17 are directly connected to the secondary winding of the transformer 3.

  As the output diodes 15 and 16, a plurality of diode elements 15A to 15N and 16A to 16N are used in parallel without using a large-capacity single diode element. Although it is difficult to obtain one general-purpose diode element, it is more economical to connect a plurality of standardized and mass-produced general-purpose diode diode elements 15A to 15N and 16A to 16N in parallel. This is because it is advantageous in terms of high-density mounting.

  The cathodes of the output diodes 15 and 16 and the other end of the output inductor 17 are connected to a pair of output terminals 6, and a plurality of output capacitors 18 and 19 are connected between the output terminals 6. In the circuit diagram shown in FIG. 1, an output capacitor 18 disposed on the same side as the output diode 15 and an output capacitor 19 disposed on the same side as the output diode 16 correspond to the arrangement structure of the output side circuit 5. Is provided. One output capacitor 18 is composed of N parallel-connected capacitor elements 18A to 18N, and the other output capacitor 19 is composed of N parallel-connected capacitor elements 19A to 19N.

  Although not shown here, as a control means for controlling the main circuit, a control circuit for turning on / off the switch element of the booster circuit 11 and a switch element 12A, 12B of the inverter circuit 14 are turned on. , And a control circuit for off control are provided. In the circuit configuration described above, when an AC input voltage from the AC power supply 1 is applied between the input terminals 2, the AC voltage in which the noise component is suppressed and removed by the input circuit 8 is all converted by the input side rectifier circuit 10 in the subsequent stage. Wave rectified. The full-wave rectified voltage is boosted by a booster circuit 11 which is an active filter circuit for suppressing harmonic currents, and is applied to capacitors 13A and 13B constituting the inverter circuit 14. The switching elements 12A and 12B are turned on and off alternately and with a dead time therebetween, whereby the voltage induced in the secondary winding of the transformer 3 is rectified by the output diodes 15 and 16, and this rectification is performed. The output voltage is smoothed by the output inductor 17 and the output capacitors 18 and 19, so that a desired output voltage is obtained between the output terminals 6.

  FIG. 2 is a partial top view showing a state of the output side circuit 5 portion of the switching power supply device 100 of the present embodiment as viewed from above. FIG. 3 is a partial side view showing a state in which the output side circuit 5 portion of the switching power supply device 100 according to the present embodiment is viewed from the side and a state in which the assembly 80 is temporarily attached to the substrate 60. FIG. 4 is a view showing a state in which the assembly 80 is viewed from above and from the side. The substrate 60 has a conductive pattern (not shown) printed on each of the solder surface 60A, which is the lower surface, and the component mounting surface 60B, which is the upper surface, and through holes in which the inner surface is plated are formed at a plurality of appropriate positions of the conductive pattern. Is formed.

  Components constituting the transformer 3 and the output side circuit 5 are mounted on the component mounting surface 60 </ b> B of the substrate 60. A bus bar 20 </ b> A is mounted as a part of the configuration of the output side circuit 5. A current supply line (a portion indicated by a thick line in FIG. 1) through which a large current from the output diodes 15 and 16 to the output capacitors 18 and 19 flows is configured by the bus bar 20A. The bus bar 20A constitutes an assembly 80 with the output diodes 15 and 16 mounted thereon. As shown in FIG. 3, the assembly 80 is soldered to the component mounting surface 60B in the same manner as other components. The assembly 80 is mounted at a position adjacent to the transformer 3 on the component mounting surface 60B. The output inductor 17 is mounted surrounded by the assembly 80. Two output terminals 6 protrude from the end of the substrate 60. Capacitor elements 18A to 18N and 19A to 19N are mounted on a component mounting surface 60B between the assembly 80 and the output terminal 6.

  FIG. 5 is a perspective view of the bus bar 20A of the present embodiment. FIG. 6 is a side view showing details of the leg terminals of the bus bar 20A. The bus bar 20A is made by punching a metal plate material (thickness: 1 mm) having good conductivity, such as copper, by pressing and bending it into a U-shaped cross section. And an elongated connecting portion 22 that connects the two side portions. The two side portions constitute a current supply line that allows a large current and a component mounting portion (large volume portion) 21 on which output diodes 15 and 16 that are electronic components are mounted. Inside each of the two component mounting portions 21, an auxiliary plate 41 having a thickness of 3 mm is overlaid so that a larger current can be handled, and the output diodes 15 and 16 are mounted on the auxiliary plate 41 ( 2 and 4). On the other hand, heat sinks (not shown) are respectively provided outside the two component mounting portions 21. That is, a heat sink (not shown) is provided on the outer side with a copper plate having a thickness of 1 mm, and an auxiliary plate 41 having a thickness of 3 mm is provided on the inner side.

  FIG. 7 is a side view showing details of leg terminals of a conventional bus bar 20Z shown for comparison. The leg terminal 29 of the conventional bus bar 20Z is divided into three protrusions, and these three protrusions are respectively inserted into the three through holes 61 provided in the substrate 60 and soldered. The inner surface of the through hole 61 is plated as described above.

  5 and 6, the leg terminal 23 of the bus bar 20A of the present embodiment is conventionally divided into three protrusions, as clearly shown in comparison with that of FIG. It is a large protrusion. With this configuration, the distal end portion 23a of the leg terminal 23 is a good heat collecting portion that collects the heat of the melted solder with the surface area enlarged compared to the conventional one. The large leg terminal 23 is inserted into a slit-like through hole 61 formed in the substrate 60 so as not to contact the periphery, and is soldered. The inner surface of the through hole 61 is plated as described above.

  In addition, a plurality of through holes 23 b are formed between the tip portion 23 a and the component mounting portion (large volume portion) 21 as a heat conduction suppressing portion that suppresses heat conduction. The plurality of through holes 23 b are formed in a staggered manner along the opening of the through hole 61 of the substrate 60. That is, the through holes 23b are formed in alignment so as to be orthogonal to the direction in which heat is transmitted from the distal end portion 23a toward the component mounting portion 21. The position where the through hole 23b is formed (precisely, the lower end position of the through hole 23b) is an appropriate height position at which the solder should be sucked up (in this embodiment, the height position of the component mounting surface 60B). It is. The plurality of through holes 23b suppress the conduction of heat from the tip portion 23a toward the component mounting portion 21.

  The flow soldering process will be described. First, an assembly 80 in which the auxiliary plate 41 and the output diodes 15 and 16 are assembled to the bus bar 20A is inserted into the slit-like through hole 61 formed in the substrate 60 as described above. Temporarily installed. Next, the board 60 on which the assembly 80 is temporarily mounted has a solder tank for storing molten solder, a jet forming part for forming a jet rising from the liquid level of the molten solder stored in the solder tank, and the board 60. It is loaded into a flow soldering apparatus (not shown) provided with a transport unit that moves the substrate 60 in one direction at a height at which the jet reaches the lower surface of the substrate. At that time, flux is applied to the solder surface 60A of the substrate 60, the substrate 60 is heated in a preheating process, and then the substrate 60 is moved in the horizontal conveyance direction while the solder surface 60A of the substrate 60 is brought into contact with the solder jet.

  Then, the solder contacts and adheres to the leg terminal 23 protruding downward from the solder surface 60A of the substrate 60 and the pad of the through hole 61 exposed to the solder surface 60A. At this time, since the tip 23a of the leg terminal 23 of the present embodiment has a surface area enlarged as described above to be a good heat collecting part, it absorbs the heat of the molten solder well and quickly becomes high temperature. In addition, since the heat absorbed by the tip 23a is blocked by the through hole 23b and does not escape to the component mounting portion (large volume portion) 21 side, the temperature from the tip 23a to the through hole 23b is very high. It becomes. Thereby, the melted solder in the solder tank adheres to the tip portion 23a, and is quickly sucked up from there to the position of the through hole 23b of an appropriate height that should be sucked up.

  As described above, in the present embodiment, the good heat collection portion provided at the tip portion 23a of the leg terminal 23 of the bus bar 20A collects the heat of the molten solder in the solder bath well. In addition, the heat conduction suppressing portion (through hole 23b) provided at a height at which the solder between the good heat collecting portion and the component mounting portion (large volume portion) 21 should be sucked is provided from the good heat collecting portion. The conduction of heat toward the component mounting portion 21 is suppressed. For this reason, the good heat collecting unit quickly raises the temperature and becomes higher than the conventional one. As a result, the molten solder in the solder tank adheres to the tip end portion 23a of the leg terminal 23 and then quickly sucks up to a position of an appropriate height that should be sucked up.

  In addition, you may provide an area expansion shape in the good heat collection part in order to expand a surface area positively. This area-enlarged shape is, for example, a plurality of irregularities or a plurality of holes provided on the surface of the leg terminal 23.

Embodiment 2. FIG.
FIG. 8 is a perspective view of a bus bar showing another embodiment of the solder connection structure according to the present invention. FIG. 9 is a side view showing details of the leg terminals of the bus bar of the present embodiment. In the bus bar 20B of the present embodiment, a plurality of slit-like long holes 23c extending in the solder sucking direction are formed in the good heat collecting portion formed at the tip portion 23a of the leg terminal 23. Due to the action of the capillary phenomenon, the melted solder is sucked up more quickly along the long hole 23c. The plurality of long holes 23c also functions to further increase the surface area of the good heat collecting portion.

  A plurality of through-holes 23 b are formed between the distal end portion 23 a of the leg terminal 23 and the component mounting portion (large volume portion) 21 as a heat conduction suppressing portion that suppresses heat conduction. The through holes 23b are formed to be aligned so as to be orthogonal to the direction in which heat is transmitted from the distal end portion 23a toward the component mounting portion 21. The position where the through hole 23b is formed is an appropriate height position where the solder should be sucked up, as in the first embodiment. The plurality of through holes 23b suppress the conduction of heat from the tip portion 23a toward the component mounting portion 21.

  As described above, in the present embodiment, since the slit-like long hole 23c is formed in the good heat collecting portion formed at the distal end portion 23a of the leg terminal 23, the molten solder is formed in the long hole 23c. Suck up more quickly along. A predetermined effect can be obtained as long as at least one slit-like long hole 23c is formed.

Embodiment 3 FIG.
FIG. 10 is a perspective view of a bus bar showing still another embodiment of the solder connection structure according to the present invention. FIG. 11 is a side view showing details of the leg terminals of the bus bar of the present embodiment. In bus bar 20 </ b> C of the present embodiment, the heat conduction suppressing portion is configured by two elongated holes 23 d extending along the boundary between tip portion 23 a and component mounting portion (large volume portion) 21. Other configurations are the same as those of the first embodiment.

  In the present embodiment, since the heat conduction suppressing portion is configured by the long hole 23d extending along the boundary between the tip portion 23a and the component mounting portion 21, heat conduction is further suppressed, and the leg portion Since the portion of the terminal 23 up to the height where the solder should be sucked up rises in temperature faster and becomes higher in temperature, the molten solder in the solder bath is quickly sucked up to the height where the solder should be sucked up. The two long holes 23d may be formed as one continuous long hole.

Embodiment 4 FIG.
FIG. 12 is a perspective view of a bus bar showing still another embodiment of the solder connection structure according to the present invention. FIG. 13 is a side view showing details of the leg terminals of the bus bar of the present embodiment. In the bus bar 20D of the present embodiment, one elongated and small leg terminal 24 is provided. In the present embodiment, the leg terminals are elongated, thereby reducing the volume and reducing the heat capacity so as to reach a high temperature quickly.

  A slit-like long hole 24c is formed at the distal end portion 24a of the leg terminal 24 to quickly suck up molten solder by the action of capillary action. Further, a through hole 24 b is formed as a heat conduction suppressing portion that suppresses heat conduction between the tip portion 24 a and the component mounting portion (large volume portion) 21. Other configurations are the same as those of the first embodiment.

  In addition, since the leg terminal 24 of the present embodiment is elongated and small, it does not have a predetermined strength for fixing the bus bar 20D to the substrate. Therefore, in order to put the bus bar 20D of the present embodiment into practical use, another fixing structure (not shown) is required.

Embodiment 5 FIG.
FIG. 14 is a side view showing details of leg terminals of a bus bar showing still another embodiment of the solder connection structure according to the present invention. In the leg terminal of the bus bar 20E of the present embodiment, in addition to the leg terminal of the first embodiment, the extended heat collecting section 25 that is cut after completion of soldering to the tip 23a constituting the good heat collecting section. Is provided. The extended heat collecting unit 25 is provided to increase the surface area for the purpose of well collecting the heat of the solder. The extended heat collection unit 25 is cut by a line indicated by a broken line in FIG. 14 after the soldering is completed.

  In the present embodiment, since the extended heat collection part 25 that is cut after completion of soldering is provided at the tip part 23a constituting the good heat collection part, the surface area of the part immersed in the solder bath is further expanded, The temperature rises faster and becomes hotter.

Embodiment 6 FIG.
FIG. 15 is a side view corresponding to a portion A of FIG. 4 showing details of the leg terminals of the bus bar showing still another embodiment of the solder connection structure according to the present invention. In the bus bar of the present embodiment, as in the first embodiment, the component mounting portion (large volume portion) 21 has an auxiliary plate 41 that expands the current supply line. In the present embodiment, the lower corner portion of the surface of the auxiliary plate 41 that faces the component mounting portion 21 is cut at approximately 45 degrees and is subjected to C1.5 chamfering so as to bypass the heat conduction path. A shape 41a is formed. Other configurations are the same as those of the first embodiment.

  In the present embodiment, when the heat of the distal end portion 23a of the leg terminal 23 is thermally conducted to the component mounting portion 21, the path is detoured by the chamfered shape 41a, so that the heat is not easily transmitted and the heat conduction is regulated. Is done. Thereby, the temperature of the leg terminal of the bus bar rises faster and becomes higher. The configuration of the present embodiment may be combined with the configurations of Embodiments 1 to 5.

Embodiment 7 FIG.
FIG. 16 is a side view corresponding to a portion A of FIG. 4 showing details of the leg terminals of the bus bar showing still another embodiment of the solder connection structure according to the present invention. In the bus bar of the present embodiment, a step shape 41b is provided at the lower corner of the surface of the auxiliary plate 41 that faces the component mounting portion (large volume portion) 21 so as to bypass the heat conduction path. The step shape 41b is formed by being milled to a thickness of 1/3 to 1/2 by an end mill, for example. Other configurations are the same as in the sixth embodiment.

  In the present embodiment, when the heat at the tip of the leg terminal 23 is conducted to the component mounting portion 21, the path is detoured by the step shape 41b, so that the heat is not easily transmitted, and the sixth embodiment The same effect can be obtained.

  As described above, the solder connection structure according to the present invention is connected, for example, between an input side circuit to which an input voltage is applied, an output side circuit for supplying an output voltage to a load, and between the input side circuit and the output side circuit. A power supply such as a switching power supply, wherein the output side circuit includes an output diode that rectifies the voltage induced in the secondary winding of the transformer, and an output inductor and an output capacitor that smooth the rectified voltage. Suitable for equipment.

BRIEF DESCRIPTION OF THE DRAWINGS It is a circuit diagram of the switching power supply which is Embodiment 1 of the power supply device concerning this invention. It is a partial top view which shows a mode that the part of the output side circuit of the switching power supply device of Embodiment 1 of the power supply device concerning this invention was seen from upper direction. It is a partial side view which shows a mode that the part of the output side circuit of the switching power supply device of Embodiment 1 was seen from the side, and a mode that the assembly is temporarily attached to a board | substrate. It is a figure which shows a mode that the assembly was seen from upper direction and a side. 3 is a perspective view of a bus bar according to Embodiment 1. FIG. FIG. 3 is a side view showing details of leg terminals of the bus bar of the first embodiment. It is a side view which shows the detail of the leg part terminal of the conventional bus bar for the comparison. 6 is a perspective view of a bus bar according to Embodiment 2. FIG. 6 is a side view showing details of leg terminals of a bus bar according to Embodiment 2. FIG. 10 is a perspective view of a bus bar according to Embodiment 3. FIG. FIG. 10 is a side view showing details of leg terminals of a bus bar according to a third embodiment. 10 is a perspective view of a bus bar according to Embodiment 4. FIG. It is a side view which shows the detail of the leg part terminal of the bus bar of Embodiment 4. It is a side view which shows the detail of the leg terminal of the bus bar of Embodiment 5. FIG. 10 is a side view corresponding to a portion A of FIG. 4 showing details of leg terminals of the bus bar of the sixth embodiment. It is a side view equivalent to the A section of Drawing 4 showing the details of the leg terminal of the bus bar of Embodiment 7.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 AC power supply 2 Input terminal 3 Transformer 4 Input side circuit 5 Output side circuit 6 Output terminal 8 Input circuit 9A, 9C, 9B, 9D Rectifier diode 10 Input side rectifier circuit 11 Booster circuit 12A, 12B Switch element 13A, 13B Capacitor 14 Inverter circuit 15, 16 Output diode 17 Output inductor 18, 19 Output capacitor 20A, 20B, 20C, 20D, 20E Bus bar (connection member)
21 Parts mounting part (large volume part, side part)
22 connection part 23, 24 leg terminal 23a, 24a tip part (good heat collection part)
23b, 24b Through hole (heat conduction suppression part)
23c, 24c long hole 23d long hole (heat conduction suppression part)
29 Leg terminal 41 Auxiliary plate 41a Chamfered shape 41b Stepped shape 60 Substrate 60A Solder surface 60B Component mounting surface 61 Through hole 80 Assembly 100 Switching power supply (power supply device)

Claims (20)

A substrate on which a wiring pattern and a through hole are formed;
At least a part of the current supply line, which is mounted on the substrate and made of a material having excellent conductivity, has a large volume portion that allows a large current, and a leg terminal that is inserted into the through hole and soldered. And a connecting member constituting
The leg terminal of the connecting member is a good heat collecting portion where the tip immersed in the solder bath collects heat well, and the height between which the solder between the good heat collecting portion and the large volume portion should be sucked up A solder connection structure, characterized in that a heat conduction suppressing portion for suppressing heat conduction is provided at the position of the solder. 2. The solder connection structure according to claim 1, wherein the heat conduction suppression unit is a plurality of through holes that are drilled side by side along a boundary between the good heat collection unit and the large volume unit. The solder connection structure according to claim 2, wherein the plurality of through holes are arranged in a staggered arrangement in a direction orthogonal to a direction in which heat is transmitted. The solder connection structure according to claim 1, wherein the heat conduction suppression unit is at least one elongated hole extending along a boundary between the good heat collection unit and the large volume unit. 5. The solder connection structure according to claim 1, wherein an elongated hole extending in a solder sucking direction is formed in the good heat collection portion. The solder connection structure according to any one of claims 1 to 5, wherein the good heat collection unit is provided with an extended heat collection unit that is cut after completion of soldering. The connection member includes an auxiliary plate that expands a current supply line in the large volume portion,
The solder according to any one of claims 1 to 6, wherein a chamfer is formed at a lower corner portion of the surface of the auxiliary plate facing the large volume portion so as to bypass a heat conduction path. Connection structure. The connection member includes an auxiliary plate that expands a current supply line in the large volume portion,
The step shape is formed in the lower corner | angular part of the surface facing the said large volume part of the said auxiliary | assistant plate so that a heat conduction path may be detoured. Solder connection structure. The solder connection structure according to any one of claims 1 to 8, wherein an area expansion shape for increasing a surface area is formed in the good heat collection part. The solder connection structure according to claim 9, wherein the area-enlarged shape is an unevenness provided on a surface of the leg terminal. An input side circuit to which an input voltage is applied, an output side circuit for supplying an output voltage to the load, and a transformer connected between the input side circuit and the output side circuit, wherein the output side circuit is connected to the transformer In a power supply device having an output diode for rectifying a voltage induced in a secondary winding, and an output inductor and an output capacitor for smoothing the rectified voltage,
A substrate on which a wiring pattern and a through hole are formed;
Mounted on the substrate, made of a material with excellent conductivity, mounted on the output diode and with a component mounting portion that allows a large current and a leg terminal that is inserted into the through hole and soldered, A connection member constituting at least a part of a current supply line between the output diode and the output capacitor;
The leg terminal of the connecting member is a good heat collecting part in which a tip part immersed in a solder bath collects heat well, and a height at which the solder between the good heat collecting part and the component mounting part should be sucked up A power conduction device that suppresses heat conduction is provided at the position of the power supply device. The power supply device according to claim 11, wherein the heat conduction suppression unit is a plurality of through holes that are perforated along a boundary between the good heat collection unit and the component mounting unit. The power supply apparatus according to claim 12, wherein the plurality of through holes are arranged in a staggered arrangement in a direction orthogonal to a direction in which heat is transmitted. The power supply device according to claim 11, wherein the heat conduction suppression unit is at least one elongated hole extending along a boundary between the good heat collection unit and the component mounting unit. The power supply apparatus according to any one of claims 11 to 14, wherein an elongated hole extending in a solder sucking direction is formed in the good heat collection unit. The power supply apparatus according to any one of claims 11 to 15, wherein the good heat collection unit is provided with an extended heat collection unit that is cut after completion of soldering. The connecting member includes an auxiliary plate that expands a current supply line in the component mounting portion, and a chamfer is formed at a lower corner portion of a surface of the auxiliary plate that faces the component mounting portion so as to bypass a heat conduction path. The power supply device according to any one of claims 11 to 16, wherein the power supply device is provided. The connecting member includes an auxiliary plate that expands a current supply line in the component mounting portion, and a step shape is formed in a lower corner portion of the surface of the auxiliary plate facing the component mounting portion so as to bypass the heat conduction path. The power supply device according to any one of claims 11 to 16, wherein the power supply device is provided. The power supply device according to any one of claims 11 to 18, wherein an area expansion shape for increasing a surface area is formed in the good heat collection unit. The power supply device according to claim 19, wherein the area-enlarged shape is an unevenness provided on a surface of the leg terminal.

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