JP2014207051A - Current auxiliary member and large current substrate using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a current auxiliary member having high heat dissipation and capable of flowing a large current therethrough.SOLUTION: A current auxiliary member 10 containing a conductive material is electrically connected to a wiring pattern of a printed board 20 by soldering. This auxiliary member includes: a plate-shaped trunk part 1 which is arranged along a first surface intersecting with the main surface of the printed board and in contact with the printed board; and two lead parts 2a, 2b extending toward the same direction from the substantial height center between both ends of the trunk part to the main surface, respectively. Then, notches 7a, 7b are formed at both upper corner parts of the trunk part 1.

Description

  The present invention relates to a current auxiliary member mounted on a printed circuit board, and more particularly to a current auxiliary member capable of passing a large current.

  Conventionally, the wiring pattern on the printed circuit board is generally about 55 μm including the plating thickness. There is a copper foil pattern with a thickness of about 200 μm capable of passing a large current, but it is rarely used because of its very high cost. Therefore, as a current assisting member that assists the wiring pattern in order to pass a large current, a member in which a metal conductor such as a sheet metal is soldered and connected to a printed board as described in Patent Document 1, for example, is used. .

  Furthermore, there is also a method of wiring a wire harness on a printed circuit board without using a metal conductor such as a sheet metal as a current auxiliary member. The wire harness is a bundle of a plurality of electric wires and covered with an insulator having high friction resistance, and has a connection terminal at the tip.

JP 2010-062249 A

  By the way, when a thick copper foil pattern with a pattern thickness of about 200 μm, a metal core substrate with a metal sandwiched between substrates, and the like are used in a large current circuit, the lead of a substrate mounted component such as a semiconductor element or a relay and the through hole of the substrate are soldered. However, due to the large heat capacity of the thick copper foil pattern, the temperature of the lead and the through hole hardly rises to the solder melting temperature, and the soldering of the through hole portion is poor in soldering by flow soldering. Therefore, manual soldering correction was required. Further, since an advanced wiring pattern etching technique is required, it has been a cause of high cost.

  On the other hand, as described in Patent Document 1, when a metal conductor such as a sheet metal is soldered and connected to a printed circuit board, current concentrates with the lowermost portion of the body portion of the metal conductor as the shortest path. Therefore, heat conduction to the entire metal conductor is deteriorated, and there is a problem that a large current cannot be passed.

  In addition, when using a method of wiring a wire harness on a printed circuit board without using a metal conductor such as a sheet metal as a current auxiliary member, additional work such as tightening the wire harness to the terminal block and holding the wiring is required. There was a problem of poor production efficiency. Furthermore, since the wire harness is covered with an insulating film, there is a problem that heat dissipation becomes low.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a current auxiliary member that has high heat dissipation and can carry a large current.

  In order to achieve the above object, a current auxiliary member according to the present invention is a current auxiliary member that is electrically connected to a wiring pattern of a printed circuit board by soldering and includes a conductive material, and intersects the main surface of the printed circuit board. A plate-like body portion arranged along the first surface and in contact with the printed circuit board, and extending from the approximate height center of both ends of the body portion toward the main surface of the body portion in the same direction. And two lead portions.

  According to the present invention, since the two lead portions extend from approximately the center of the height at both ends of the body portion, the heat generated during energization is concentrated at the center of the body portion, and the heat is distributed to the entire top and bottom of the body portion. Since it is transmitted efficiently, a current assisting member having high heat dissipation and capable of supplying a large current is realized.

  In particular, the two lead portions extend from the body portion in the same direction with respect to the main surface so that the wind blows from the direction in which the lead portion extends toward the main surface of the current auxiliary member. When configured, the wind that flows on the printed circuit board and hits the body portion flows along the body portion and hits each lead portion, and the heat dissipation from the lead portion can be improved by this wind.

3 is a perspective view showing a current auxiliary member according to Embodiment 1. FIG. It is a front view shown in the state where the same current auxiliary member was mounted on the substrate. It is a top view shown in the state where the same current auxiliary member was mounted on the substrate. It is a side view shown in the state where the same current auxiliary member was mounted on the substrate. It is a figure which shows the electric current auxiliary member before stamping from a metal plate. It is explanatory drawing for demonstrating the thermal radiation effect | action of the current auxiliary member by Embodiment 1, (a) is a front view, (b) is a side view. It is a figure which shows the wind which flows around the electric current auxiliary member by Embodiment 1. FIG. It is the sectional view on the AA line of FIG. 1b. It is a figure which shows the electric current auxiliary member by Embodiment 1 in the state mounted in the board | substrate arrange | positioned at a perpendicular direction. It is a figure which shows the example of arrangement | positioning on the board | substrate of the electric current auxiliary member by Embodiment 1. FIG. It is a front view shown in the state which mounted the current auxiliary member by Embodiment 2 on the board | substrate. It is a figure which shows the current auxiliary member by a prior art, (a) is a front view, (b) is a side view. It is explanatory drawing for demonstrating the thermal radiation effect | action of the current auxiliary member by a prior art. It is a figure which shows the electric current auxiliary member by a prior art mounted in the board | substrate arrange | positioned at the perpendicular direction, (a) is a case where the main surface of an electric current auxiliary member is parallel with respect to the ground, (b) is perpendicular | vertical. Shows the case.

Embodiment 1 FIG.
1a to 1d are a perspective view, a front view, a top view, and a side view, respectively, showing a current assisting member according to Embodiment 1 of the present invention, and FIGS.
As shown in FIG. 1a, the current auxiliary member 10 according to the present embodiment includes a plate-shaped body portion 1 and two lead portions 2a and 2b. The current auxiliary member 10 is made of a conductive material such as a metal conductor. For example, pure copper, brass, aluminum or the like is used as the metal conductor. As will be described later, the length of the lead portions 2a and 2b is preferably set to a length that sufficiently heats the lead portions 2a and 2b during soldering.

  As shown in FIGS. 1b and 1c, the body portion 1 of the current assisting member 10 is in contact with the printed circuit board 20 disposed in the xy plane on the lowermost surface, and is perpendicular to or intersects the main surface. It is arranged along the surface. The perpendicular plane or the intersecting plane is the first plane of the claims, and is the xz plane in the drawing.

  The lead portions 2a and 2b extend from the body portion 1 toward the printed circuit board 20, and are bent in the middle of the lead portions 2a and 2b, and the shoulder portions 4a and 4b on the body portion 1 side and the leg portions 3a on the printed circuit board 20 side. 3b. As shown in FIG. 1, the lead portions 2 a and 2 b are drawn from both ends (+ x end, −x end) of the body portion 1 in the same direction (−y direction) with respect to the main surface of the body portion 1. . As shown in FIG. 1d, the legs 3a and 3b are inserted perpendicularly to the through holes 6a and 6b of the printed circuit board 20, soldered, and electrically connected to a wiring pattern (not shown) of the printed circuit board 20. The On the other hand, the shoulder portions 4a and 4b are connected to the body portion 1 by connecting portions 5a and 5b. Each of the connecting portions 5a and 5b is located at the approximate height center of the body portion 1, that is, approximately the center in the z direction. The approximate center in the z direction where the connecting portions 5a and 5b are located is indicated by a one-dot chain line in FIGS. 1a and 1b.

  Cutout portions 7a and 7b having the same width as the lead portions 2a and 2b are formed at the upper right corner and the upper left corner of the body portion 1. The notches 7a and 7b are formed in the manufacturing process as described below, and are not necessarily formed.

  Here, an exemplary size of the current auxiliary member 10 when the wiring pattern on the printed circuit board 20 is about 55 μm including the plating thickness will be described. The current auxiliary member 10 has a width of about 30 mm, a height of about 10 mm, and a thickness of about 3 mm. The width, height, and thickness of the current auxiliary member 10 are the lengths in the x, z, and y directions of FIG. About the magnitude | size of a width | variety and height, the code | symbol w and h are attached | subjected and shown in FIG. 2 demonstrated below.

FIG. 2 is a diagram showing a current auxiliary member before punching from a metal plate.
A dotted line indicates a portion to be punched. As shown in FIG. 2, a plurality of current assisting members 10 are simultaneously formed from one metal plate by punching. Cutouts 7 a and 7 b are formed in the upper right corner and upper left corner of the body portion 1. Lead parts 2 a and 2 b extending from the lowermost part of the body part 1 to the lower side are formed at the lower right corner and the lower left corner of the body part 1. That is, a notch portion of the lower current auxiliary member is formed in a portion of the lead portion that protrudes downward from the lowermost portion of the body portion. Therefore, the widths of the notches 7a and 7b are equal to the widths of the lead portions 2a and 2b. After the punching process, the lead parts 2a and 2b are bent between the leg part 3a (3b) and the shoulder part 4a (4b), and formed into the shape shown in FIG.

  In this manner, by forming the plurality of current auxiliary members 10 from a single metal plate, the metal plate can be used without waste, and the production cost can be reduced. Further, since the current auxiliary member 10 can be created only by a simple process of punching and bending, production efficiency can be improved.

FIG. 3 is an explanatory diagram for explaining the heat dissipation action of the current auxiliary member according to the first embodiment.
In general, when a potential difference occurs in a metal conductor, the current flowing through the metal conductor does not flow uniformly over the entire conductor, but has a characteristic of flowing in a shortest distance. Therefore, Joule heat is also concentrated in the shortest distance. Moreover, the heat generated in the metal conductor is dissipated from the surface of the metal conductor into the air. Therefore, in order to efficiently dissipate heat from the current auxiliary member 10 made of a conductive material, it is preferable to diffuse the generated heat over a wide range of the body portion 1.

  Here, FIG. 9 is a diagram showing a current assisting member according to the prior art. (A) is a front view, (b) is a side view. Moreover, FIG. 10 is explanatory drawing for demonstrating the thermal radiation effect | action of the said current auxiliary member. In the current assisting member according to the prior art, the three lead portions are not drawn out with respect to the body portion. Therefore, as indicated by the thick arrows in the figure, the current flows in a concentrated manner at the lowermost portion of the current auxiliary member serving as the shortest path, and heat generation is concentrated in the lowermost portion. Therefore, heat conduction can be performed only in the upward direction of the body portion, the range in which the generated heat can be diffused is narrowed, and heat dissipation from the body portion is reduced.

  On the other hand, returning to FIG. 3, when the lead portions 2 a and 2 b are pulled out from the body portion 1 as in the current assisting member 10 according to the present embodiment, as shown above, it is indicated by a one-dot chain line in FIG. The path connecting the connecting portions 5a and 5b located at the approximate center (height center) in the z direction is the shortest distance. Therefore, as shown in FIG. 3B, the current flows concentrically at the height center of the body portion 1 with the connecting portion 5a (5b) as the entrance and exit of the current path, and the heat generation is also concentrated in the center.

  Therefore, as shown in FIG. 3A, the heat generated in the body part 1 can be thermally conducted up and down the body part 1. As a result, heat generation can be widely diffused throughout the body portion 1, and heat dissipation from the body portion 1 is improved.

  Here, since the distance from the tip of the leg portions 3a, 3b of the lead portions 2a, 2b to the connecting portions 5a, 5b is sufficiently long, it is difficult to diffuse heat generated in the lead portions 2a, 2b to the body portion 1 when energized. It is also considered that the lead portions 2a and 2b are overheated and the heat dissipation performance is lowered as a whole. Therefore, the heat radiation of the lead portions 2a and 2b will be described next.

FIG. 4 is a diagram showing the wind flowing around the current auxiliary member according to the first embodiment.
A printed circuit board that conducts a large current such that a current auxiliary member is mounted is also equipped with a heat-generating component, such as a power semiconductor element, to which heat radiating fins are attached, and a fan that blows air to cool them is often attached. . Here, as an example, a case where the wind blows in the + y direction as shown in FIG. 4 will be described. The lead portions 2a and 2b are drawn out in the direction of the wind direction. In other words, wind is blown from the direction in which the lead portions 2a and 2b extend toward the main surface of the current auxiliary member 10.

  When a wind blown from the fan or the like toward the body portion 1 toward the + y direction strikes the body portion 1, the wind flows along both the + x direction and the −x direction along the main surface of the body portion 1, and the lead portion 2a. , 2b. Both the wind flowing along the main surface of the body part 1 and the wind blowing in the + y direction toward the body part 1 hit the lead parts 2a and 2b, and heat dissipation from the lead parts 2a and 2b is achieved. Can be improved.

Next, the advantage by taking the length of lead part 2a, 2b, ie, the length from the front-end | tip of leg part 3a, 3b to the connection part 5a, 5b moderately is demonstrated.
As described above, according to the present embodiment, the heat dissipation from the lead portions 2a and 2b is improved. Of the received heat, the amount of heat transmitted to the body portion 1 can be appropriately reduced so that the lead portions 2a and 2b are sufficiently heated. Thereby, the solder rise in the through holes 6a and 6b is improved, and a soldering failure can be prevented.

Next, the vibration resistance and strength of the current auxiliary member 10 will be described.
In the current assisting member according to the prior art (see FIG. 9), the lead portions at both ends are soldered to the printed circuit board. Further, since the vibration resistance is weak only by soldering, the central lead portion is press-fitted into the printed circuit board. In this way, vibration resistance is ensured by being connected to the printed circuit board at three points. When press-fitting the lead portion, a strong force is required, and it is assumed that a jig is required.

FIG. 5 is a cross-sectional view taken along the line AA of FIG. 1b and shows a state where the current auxiliary member 10 is inserted into the through holes 6a and 6b.
The current auxiliary member 10 is in contact with the printed circuit board 20 on the lowermost surface of the body portion 1. As is apparent from FIG. 5, in the first embodiment, the width of the body portion 1 is sufficiently larger than the widths of the lead portions 2a and 2b. Therefore, the current auxiliary member 10 is provided with strong vibration resistance simply by connecting the two lead portions 2a and 2b to the through holes 6a and 6b by soldering without joining the body portion 1 to the printed circuit board 20. be able to. At this time, there is no need to press-fit the lead portion, and no jig is required.

  Hereinafter, in the description of the first embodiment, the + y direction is the vertical direction. “Clockwise” refers to rotation in the yz plane.

FIG. 11 is a diagram showing a current auxiliary member according to the prior art mounted on a substrate arranged in a vertical direction. FIG. 11A shows the case where the main surface of the current auxiliary member is parallel to the ground, and FIG. 11B shows the case where it is vertical.
When the current assisting member 10 is arranged as shown in FIG. 11A, a load is applied in a direction in which the current assisting member 10 is rotated clockwise with the soldering portion as a fulcrum. And there is no other mechanism for supporting the load, and therefore solder cracks are likely to occur.

  Next, consider the case where the current auxiliary member 10 is arranged as shown in FIG. The lead portion at the center in the y direction is only press-fitted, and the force for supporting the current auxiliary member 10 is weak. Then, a load is applied in the direction in which the current auxiliary member 10 is rotated clockwise at the soldering portions at both ends in the y direction. At the soldering position at the upper end (−y end), these two loads are added together, and a force toward the right direction (+ z direction) acts. On the other hand, at the soldering position at the lower end (+ y end), a force toward the left direction (−z direction) acts. Therefore, solder cracks are likely to occur even in the arrangement of FIG.

FIG. 6 is a diagram showing the current assisting member according to Embodiment 1 mounted on a substrate arranged in the vertical direction. The arrangement of the current auxiliary member in FIG. 6 corresponds to the arrangement in FIG.
As shown in FIG. 6, when the current auxiliary member 10 is arranged so that the lead portion 2a (2b) is pulled out in the upward direction (−y direction), the current auxiliary member 10 is placed at the position of the through hole 6a (6b). Although the load of the direction rotated around is added, this load is supported by the drag N of the right direction (+ z direction) added from the printed circuit board 20 to the lower surface of the trunk | drum 1, and, thereby, generation | occurrence | production of a solder crack can be suppressed.

  Furthermore, when the printed circuit board 20 is arranged as shown in FIG. 6, there is an advantage that the heat radiation from the lead portions 2a and 2b can be improved by using the wind generated by the rising airflow.

FIG. 7 is a diagram illustrating an arrangement example of the current auxiliary member according to the first embodiment on a substrate.
When many electronic components are mounted on a printed circuit board on which the current auxiliary member 10 is mounted or a large current circuit board, for example, the relay 30 or the like generates a high level of radiated noise during switching, and the digital IC 40 or the like generates noise. It is weak in nature. Therefore, when the relay 30 and the digital IC 40 are mounted on the same printed circuit board 20, it is necessary to mount the relay 30 and the digital IC 40 at positions separated from each other in order to prevent malfunction, which is a factor of increasing the size of the circuit board.

  Therefore, as illustrated in FIG. 7, the current auxiliary member 10 made of a conductive material can be disposed as a shield that shields radiation noise propagating between electronic components mounted on the printed circuit board 20. Specifically, the current assisting member 10 is disposed so that the plate-shaped body portion 1 partitions the relay 30 and the digital IC 40. Thereby, the distance between two electronic components can be shortened, and the board | substrate can be reduced in size.

Embodiment 2. FIG.
FIG. 8 is a front view showing the current auxiliary member according to the second embodiment mounted on a substrate.
As shown in FIG. 8, in the current auxiliary member 10 according to the second embodiment, gaps 8 a and 8 b are formed between the lead parts 2 a and 2 b and the body part 1, respectively. Other configurations are the same as those in the first embodiment.

  The gaps 8 a and 8 b extend from the height of the connecting portions 5 a and 5 b shown by the one-dot chain line in FIG. 7, that is, from the height center of the body portion 1 to the main surface of the printed circuit board 20.

  Generally, the metal plate and the printed circuit board 20 expand or contract due to a change in ambient temperature. At this time, if stress is applied to the soldered portion, cracks may occur in the soldered portion in accordance with the thermal stress. In the current auxiliary member 10 according to the second embodiment, thermal stress due to expansion and expansion / contraction of the current auxiliary member 10 and the printed circuit board 20 can be absorbed by the gap portions 8a and 8b, and cracks in the soldering portion can be suppressed.

  Although it is possible to reduce the stress on the soldering part during soldering and to suppress cracks in the soldering part, in that case, the accuracy of the metal plate dimensional tolerance is high with respect to the pitch of the through holes 6a and 6b. And a high-precision processing machine is required.

  In the current auxiliary member 10 according to the second embodiment, since the same effect can be obtained by providing the gap portions 8a and 8b, the dimensional tolerance of the metal plate can be lowered, and the processing machine with low accuracy can be manufactured. .

  1 body part, 2a, 2b lead part, 3a, 3b leg part, 4a, 4b shoulder part, 5a, 5b connecting part, 6a, 6b through hole, 7a, 7b notch part, 8a, 8b gap part, 10 current assist Members, 20 printed circuit boards, 30 relays, 40 digital ICs.

Claims (6)

A current auxiliary member that is electrically connected to the wiring pattern of the printed circuit board by soldering and includes a conductive material,
A plate-like body portion that is disposed along a first surface intersecting with a main surface of the printed circuit board and is in contact with the printed circuit board;
A current assisting member comprising: two lead portions each extending in the same direction with respect to a main surface of the body portion from a substantially height center of both ends of the body portion.   The current assisting member according to claim 1, wherein notches are formed in both upper corners of the body portion.   The current auxiliary member according to claim 1, wherein a gap is formed between each of the two lead portions and the body portion.   The two lead parts each have a leg part inserted perpendicularly to a through hole of the printed circuit board, and a shoulder part connecting the leg part and the body part, respectively. The current auxiliary member according to 1.   A high-current substrate using the current auxiliary member according to claim 1.   The high current substrate according to claim 5, wherein the current auxiliary member is disposed as a shield that shields radiation noise propagating between electronic components.

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