JP2013008726A - Printed board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a printed board with a new structure, which can continuously solder a plurality of land rows separated from each other by drag soldering.SOLUTION: In a printed board 10, a plurality of land portions 14 arranged in through holes 12 into which lead portions 20 of mounted components 16a and 16b are inserted are aligned, and the land portions 14 and the lead portions 20 are soldered to each other by drag soldering. A first land row 22a constituted by a group of the plurality of aligned land portions and a second land row 22b are disposed separating from each other. An intermediate dummy land portion 26 is installed to extend between an end on the terminal side of the first land row 22a and an end on the start side of the second land row 22b.

Description

  The present invention relates to a printed circuit board in which a lead portion of a mounted component is inserted and soldered to a land portion provided in a through hole.

  Conventionally, in a printed circuit board in which printed wiring is formed on the surface of an insulating substrate, a plurality of land portions provided with through holes are arranged in an aligned manner, while relays and connectors mounted on the printed circuit board in these through holes are provided. The lead part of the mounting component and the printed wiring are connected via solder by inserting and soldering the lead part of the mounting part.

  By the way, in such a printed circuit board, in order to efficiently solder the lead part and the land part of the mounting component, the heating iron part of the soldering device is moved continuously in the through hole alignment direction. It has been proposed to perform soldering by so-called pull soldering, in which lead portions are soldered to a plurality of land portions. For example, those described in Japanese Patent Application Laid-Open No. 2005-294480 (Patent Document 1). According to such pull soldering, continuous soldering to a plurality of land portions is possible, so that the work time is shorter than the so-called robot soldering in which soldering is performed by a soldering device for each land portion. Can be greatly shortened.

  However, on a printed circuit board, for example, a plurality of land rows including a plurality of land portions are often formed for each mounted component, and the plurality of land rows are often provided apart from each other. In this case, even when multiple lands and lead parts are continuously soldered by pull soldering, after continuous heating by moving the heating iron part on one land row Then, once the heating iron part is pulled up on the printed circuit board from the end of the soldering end of the land row, the heating iron is moved to the end of the soldering start side of the other land row. It is necessary to place the heating iron part on the printed circuit board again. As a result, movement and control of the heating iron are complicated, and there are cases where the workability of soldering by drag soldering cannot be sufficiently improved.

  In particular, when the heating iron part is pulled up from the printed circuit board after soldering of one land row, the excess solder stored in the heating iron part falls on the printed circuit board and remains in a ball shape. In some cases, so-called solder balls are formed, and the solder balls may cause damage or failure of the printed circuit board or other mounted components.

  Furthermore, once the heating iron is lifted onto the printed circuit board, when starting soldering with another land row by drawing solder, problems such as insufficient solder supply may occur. With the lifting and lowering operations of the iron part, it has become very difficult to stabilize the solder supply amount and the heating state of the heating iron part.

JP 2005-294480 A

  The present invention has been made in the background of the above-mentioned circumstances, and the solution is to print a novel structure capable of continuously soldering a plurality of land rows separated from each other by pull soldering. It is to provide a substrate.

  In the first aspect of the present invention, a plurality of land portions provided in the through holes are arranged and arranged, and a lead portion of a mounting component is inserted into the through holes of the plurality of land portions, and the land portions In the printed circuit board in which the lead portions are soldered by pull soldering, a first land row composed of a group of the plurality of arranged land portions, and another group of the arranged plurality of land portions. The second land row composed of the first land row and the end point side of the first land row in the draw solder, and the start point side of the second land row in the draw solder An intermediate dummy land portion extending between the end portion and the end portion is provided.

  In the printed circuit board having the structure according to this embodiment, an intermediate dummy land portion extending between the end point side end portion of the first land row and the start point side end portion of the second land row is provided. When the soldering is performed and the heating iron part is moved from the first land row to the second land row, the heating iron portion can be slid and moved on the intermediate dummy land portion. Therefore, it is not necessary to once lift the heating iron part onto the printed circuit board and move it to the second land row, so that the soldering workability by drawing solder can be improved.

  Further, since the heating iron part can be placed on the intermediate dummy land part and moved along the intermediate dummy land part, excess solder is absorbed by the intermediate dummy land part, The heating temperature and the required amount of solder can be maintained stably, and problems such as the formation of solder bridges on the end point side of the first land row and the lack of solder on the start point side of the second land row can occur. This can advantageously be prevented.

  In addition, when the first land row and the second land row are moved, it is not necessary to pull up the heating iron on the printed circuit board. Occurrence of problems such as breakage can be prevented.

  In addition, the intermediate dummy land portion only needs to extend between the end point side end portion of the first land row and the start point side end portion of the second land row, and those extending linearly between them, Any of those that extend by bending or bending is included.

  According to a second aspect of the present invention, in the one described in the first aspect, the first land row and the second land row are in a straight line spaced apart from each other in the alignment direction of the plurality of land portions. While being arranged in alignment, the intermediate dummy land portion extending in the alignment direction is provided between the first land row and the second land row.

  According to this aspect, the intermediate dummy land portion provided between the first land row and the second land row arranged in alignment on a straight line extends linearly in the alignment direction. Therefore, the first land row and the second land row can be soldered continuously only by moving the heating iron part during the draw soldering along a straight line. Stabilization and efficiency improvement.

  According to a third aspect of the present invention, in the one described in the first or second aspect, an end of the intermediate dummy land portion on the first land row side is in an extending direction of the intermediate dummy land portion. The extended land portions extending on both sides in the intersecting direction are provided to be connected.

  According to this aspect, the extended land portion of the intermediate dummy land portion is provided adjacent to the end portion on the end point side of the first land row where surplus solder is likely to be a problem. Therefore, when the soldering of the first land row is completed, the heating iron portion can be moved to the intermediate dummy land portion, and the surplus solder can be quickly absorbed by the extended land portion. In particular, since the extended land portion extends across the extending direction of the intermediate dummy land portion, that is, the moving direction of the heating iron portion, the extended land portion is heated by contacting the heating iron portion. It will be. Thereby, the excess solder that has contacted the extended land portion is maintained at a relatively high temperature, and the excess solder can be quickly absorbed by the extended land portion.

  According to a fourth aspect of the present invention, in the device according to any one of the first to third aspects, the land portion and the lead portion are soldered by the pull solder using lead-free solder. Is.

  According to this aspect, the first land row and the second land row can be continuously soldered by sliding on the intermediate dummy land portion without lifting the heating iron portion from the printed circuit board. The heating state and solder supply state of the ironing part can be stabilized. Therefore, even when lead-free solder having a high melting point is used, the first land row and the second land row can be continuously soldered by pull solder in a stable state.

  According to the present invention, since the intermediate dummy land portion extending between the end point side end portion of the first land row and the start point side end portion of the second land row is provided, the intermediate land portion is interposed via the intermediate dummy land portion. Further, it is possible to continuously perform soldering by pulling solder from the end point side end portion of the first land row to the end point side end portion of the second land row, and the workability of soldering can be improved. Further, since the heating iron can be placed on the intermediate dummy land portion and moved along the intermediate dummy land portion, the necessary amount of solder is absorbed while absorbing excess solder into the intermediate dummy land portion. It can be stably maintained, and troubles such as formation of a solder bridge between each land row and the intermediate dummy land can be advantageously prevented.

The principal part expansion disassembled perspective view which shows the surface side of the printed circuit board as one Embodiment of this invention. The principal part enlarged plan view which shows the back surface side of the printed circuit board shown in FIG. The enlarged plan view which shows an example of the land part which comprises the printed circuit board which concerns on this invention. 1 shows an example of a dummy land portion constituting a printed circuit board according to the present invention, wherein (a) is an enlarged plan view of a dummy land portion on one end side in the land alignment direction, and (b) is a dummy land portion on the other end side in the land alignment direction. FIG. The enlarged plan view which shows an example of the intermediate dummy land part which comprises the printed circuit board which concerns on this invention. FIG. 4 is an enlarged cross-sectional view showing a state of pull soldering using a land portion and an intermediate dummy land portion that constitute a printed circuit board according to the present invention, and is a view corresponding to the VI-VI cross-sectional view of FIG. 2. It is an expanded sectional view which shows the mode of the pull solder using the land part which comprises the printed circuit board which concerns on this invention, Comprising: The figure corresponded in VII-VII sectional drawing of FIG. The enlarged plan view which shows another example of the intermediate | middle dummy land part which comprises the printed circuit board which concerns on this invention.

  Embodiments of the present invention will be described below with reference to the drawings.

  First, the principal part of the printed circuit board 10 as 1st embodiment of this invention is shown by FIG. 1 and FIG. 2 from the surface side and the back surface side. The printed board 10 is obtained by forming a printed wiring (not shown) on a substantially rectangular flat board surface made of a known insulating material. A plurality of through-holes 12 arranged in alignment along the side edge are formed through the side edge of the printed circuit board 10. Land portions 14 made of a conductor such as copper foil are integrally formed on the inner peripheral surface of each through-hole 12 and on the opening peripheral portion on the front surface side and the back surface side of the printed circuit board 10. Electrically connected. FIG. 1 shows the front surface land portion 14a constituting the land portion 14, while FIG. 2 shows the back surface land portion 14b constituting the land portion 14.

  The mounting components 16 a and 16 b such as connectors mounted on the printed circuit board 10 have a plurality of lead portions 20 that are fixed to the resin pedestal 18, and the leading ends of these lead portions 20 are the surface of the printed circuit board 10. The resin pedestal 18 is placed on the printed circuit board 10 in a state of being inserted into the through hole 12 from the side and protruding to the back surface side of the printed circuit board 10. The plurality of lead portions 20 and the land portions 14 are pulled and soldered from the back surface side of the printed circuit board 10 so that the mounting components 16 a and 16 b are mounted on the printed circuit board 10.

  As shown in FIG. 2, the first land row 22a through which the lead part 20 of the mounting component 16a is inserted and the lead part 20 of the mounting component 16b are provided on the back side of the printed circuit board 10 to be soldered by pull soldering. The second land rows 22b to be inserted are arranged on a straight line apart from each other in the alignment direction of the land portions 14. Each land row 22a, 22b is constituted by a plurality of land portions 14 provided in the through hole 12 and arranged in groups.

  In the alignment direction of the first land row 22a and the second land row 22b, the dummy land portions 24a and 24b are adjacent to the back surface land portion 14b outside the alignment direction of the back surface land portions 14b located on both ends. Each is provided. An intermediate dummy land portion 26 extending in the alignment direction is provided between the first land row 22a and the second land row 22b in the alignment direction of the first land row 22a and the second land row 22b. . In addition, the circumference | surroundings of each back surface land part 14b, the dummy land parts 24a and 24b, and the intermediate dummy land part 26 are coat | covered with the well-known solder resist layer 28. FIG.

  FIG. 3 shows an enlarged plan view of the back surface land portion 14b. The back surface land portion 14b has a substantially rectangular outer shape in plan view, and extends to both sides in a direction (vertical direction in FIG. 3) orthogonal to the alignment direction (left and right direction in FIG. 3) of the back surface land portion 14b. A pair of extended land portions 30a and 30b are connected to each other. The extended land portions 30a and 30b extend with a substantially constant width, and have a substantially rectangular outer shape in plan view.

  Narrowed portions 32a and 32b are provided at the connecting portion of the back surface land portion 14b and the extended land portions 30a and 30b. The narrowed portions 32a and 32b are gradually reduced in length in the alignment direction of the back surface land portion 14b (left and right direction in FIG. 3) outward in the extending direction of the extended land portions 30a and 30b. The minimum length dimension: L2 is set to be larger than the outer diameter of the through hole 12: L1. The extended land portions 30a and 30b extend outward while maintaining the minimum length dimension L2 of the narrowed portions 32a and 32b. The length dimension L3 from the outer edge of the through hole 12 to the extended end portions of the extended land portions 30a and 30b is set to be equal to or greater than the outer dimension of the through hole 12: L1.

  Next, FIGS. 4A and 4B are enlarged plan views of the dummy land portions 24a and 24b. The dummy land portions 24a and 24b have a substantially rectangular outer shape in plan view, like the back surface land portion 14b. Since the dummy land portions 24a and 24b are not connected to the lead portion 20 of the mounted component, the through hole 12 is not provided. In addition, the dummy land portions 24a and 24b include a pair of extended land portions 34a extending to both sides in a direction (vertical direction in FIG. 4) orthogonal to the horizontal direction in FIG. 4 which is the alignment direction of the back surface land portion 14b. 34b is connected and provided.

  In addition, narrowed portions 32a and 32b similar to the case of the back surface land portion 14b are provided at the connecting portions of the dummy land portions 24a and 24b and the extended land portions 34a and 34b, respectively. And the length dimension L4 (left-right direction in FIG. 4) reduced by the narrowed portions 32a and 32b is maintained, and the extended land portions 34a and 34b extend outward, and are substantially rectangular in plan view. It has an outer shape. In the present embodiment, the length dimension L4 of the extended land portions 34a and 34b is set to be substantially the same as the length dimension L2 of the extended land portions 30a and 30b of the back surface land portion 14b.

  As shown in FIG. 4 (a), in the alignment direction of the back surface land portion 14b of the first land row 22a, the back surface land portion at the end (left end in FIG. 2) that is the starting point when soldering by drag solder described later is performed. In the dummy land portion 24a provided adjacent to the outer side of the alignment direction 14b, an extended land portion 34c extending outward in the alignment direction (left side in FIGS. 2 and 4) is provided via the throttle portions 32a and 32b. It is connected. On the other hand, as shown in FIG. 4B, in the alignment direction of the back surface land portion 14b of the second land row 22b, the back surface of the end portion (the right end in FIG. 2) that is the end point when soldering by drag solder described later is performed. In the dummy land portion 24b provided adjacent to the outside of the land portion 14b in the alignment direction, an extended land portion 34c extending outward in the alignment direction (right side in FIGS. 2 and 4) is connected to the throttle portions 32a and 32b. Are connected through. The extended land portions 34c and 34c both maintain the length dimension L4 (vertical direction in FIG. 4) reduced by the narrowed portions 32a and 32b, and are located outward in the alignment direction of the back surface land portion 14b. 4 respectively extend to the left and right sides in FIG. 4 and have a substantially rectangular outer shape in plan view.

  Further, FIG. 5 shows an enlarged plan view of the intermediate dummy land portion 26. The intermediate dummy land portion 26 extends along the alignment direction between the end point side end portion of the first land row 22a in the draw solder and the end point end portion of the second land row 22b in the draw solder. It has an outer shape of a substantially rectangular shape in plan view. Since the intermediate dummy land portion 26 is not connected to the lead portion 20 of the mounted component, the through hole 12 is not provided as in the dummy land portions 24a and 24b. Here, the length dimension L5 of the intermediate dummy land portion 26 can be arbitrarily set. However, preferably, as shown in FIG. 2, in the alignment direction of the back surface land portion 14b, between the adjacent back surface land portions 14b. It is preferable that the same gap dimension: w is left on both sides and the length extends over the entire length between the first land row 22a and the second land row 22b.

  Further, the intermediate dummy land portion 26 has an end portion on the first land row 22a side in a direction (vertical direction in FIG. 5) intersecting with the horizontal direction in FIG. A pair of extended land portions 36a, 36b extending to both sides are provided in a continuous manner. The crossing angle α of the extended land portions 36a and 36b with respect to the alignment direction of the back surface land portion 14b is preferably 30 ° to 150 °, similarly to the extended land portions 30a and 30b provided on the back surface land portion 14b. The angle is more preferably 60 ° to 120 °, and still more preferably 90 ° (orthogonal). When the crossing angle α is 150 ° or more, the surface tension does not sufficiently act on the solder between the end on the first land row 22a side, and a solder bridge is formed without properly dividing the solder. On the other hand, when the crossing angle: α is 30 ° or less, the distance between the end on the first land row 22a side and the intermediate dummy land 26 increases, and the solder falls on the printed circuit board 10. It is because there is a possibility of doing. In the present embodiment, the crossing angle: α of the extending direction of the extended land portions 36a, 36b with respect to the alignment direction of the back surface land portion 14b: α is 90 °, and the solder adhered to the extended land portions 36a, 36b. And a distance from the solder adhering to the end of the first land row 22a on the end point side are appropriately secured.

  The connecting portions of the intermediate dummy land portion 26 and the extended land portions 36a and 36b are respectively provided with the narrowed portions 32a and 32b similar to the case of the back surface land portion 14b. And the length dimension L6 (left-right direction in FIG. 5) made small by the aperture | diaphragm | squeeze parts 32a and 32b is maintained, and the extension land parts 36a and 36b are extended outward, and are substantially rectangular in planar view. It has an outer shape. In this embodiment, the length dimension L6 of the extended land portions 36a and 36b is set to be substantially the same as the length dimension L2 of the extended land portions 30a and 30b connected to the back surface land portion 14b. Yes.

  Next, a soldering method using the printed circuit board 10 of this embodiment having such a structure will be described with reference to FIGS. FIG. 6 schematically shows a state where pull soldering is performed in the printed circuit board 10 shown in FIG. 2, and corresponds to a cross-sectional view taken along the line VI-VI in FIG. 2.

  First, prior to soldering, electric power is supplied to a soldering device (not shown), and the heating iron 38 is heated to a degree sufficient to melt the thread-like solder 42 supplied from the solder supply unit 40. The In the present embodiment, lead-free solder is used as the solder 42. Further, when performing the drag soldering, the heating iron part 38 is moved in the moving direction indicated by the arrow S in FIG. 6, that is, from the left side to the right side in FIG. 2, so that the lead part 20 and the land part 14 are moved. It will be soldered continuously. Here, the temperature, moving speed, solder supply amount, etc. of the heating iron part 38 are appropriately set so that the molten solder 42 is appropriately divided between the land parts 14 so that a solder fillet 44 described later is formed satisfactorily. It has been adjusted.

  The heating iron 38 that has been heated is first placed on a dummy land portion 24a provided adjacent to the back surface land portion 14b located at the end of the first land row 22a. The process waits on the dummy land portion 24a until a proper amount of solder 42 supplied from 40 is melted and reaches the end of the heating iron portion 38.

  Thereafter, the land portion arranged in the moving direction is arranged by moving the heating iron portion 38 in the moving direction while supplying an appropriate amount of solder 42 from the solder supplying portion 40 to the heating iron portion 38 and melting it. 14 and the lead portion 20 are sequentially soldered. That is, when the heating iron portion 38 passes over each back surface land portion 14b, the solder 42 melted from the heating iron portion 38 is supplied to the through hole 12, and the through hole 12 is filled with the solder 42. As a result, a solder fillet 44 is formed. Thereby, each land part 14 is soldered to each lead part 20.

  As described above, the heating iron 38 moves in the moving direction from the dummy land 24a on the starting point side, and supplies the solder 42 to each land 14 and passes through the first land row 22a. Thereafter, as shown in FIG. 6, the heating iron 38 is located between the end of the first land row 22a at the end of soldering and the end of the second land row 22b at the starting point. The intermediate dummy land portion 26 is extended. Here, since each land row 22a, 22b and the intermediate dummy land portion 26 are aligned and arranged in a straight line, the moving direction and moving speed of the heating iron portion 38 are continuously maintained in a constant state. Drag soldering is performed. The heating iron portion 38 passes through the second land row 22b through the intermediate dummy land portion 26, and then reaches the dummy land portion 24b on the end point side to complete the drawing soldering. At this time, as in the case of the first land row 22a, the through holes 12 are formed by the solder 42 melted from the heating iron 38 when the heating iron 38 passes over each back surface land 14b. The land portions 14 are filled and soldered to the lead portions 20.

  The heating iron portion 38 that has passed through the second land row 22b is finally placed on a dummy land portion 24b provided adjacent to the back surface land portion 14b located at the end of the second land row 22b. After the soldering is completed, the printed circuit board 10 is pulled up.

  Next, FIG. 7 shows a state of pull soldering in a direction orthogonal to the moving direction of the heating iron 38, and is a view corresponding to the VII-VII sectional view of FIG. As shown in FIG. 7, the heating iron part 38 is provided with a leading end recessed groove 46 through which the lead part 20 can be inserted. Therefore, when the lead soldering is performed, the lead part 20 can pass through the concave groove 46, so that the interference between the lead part 20 and the heating iron part 38 is avoided when the heating iron part 38 is moved. It has become.

In addition, extended land portions 30a and 30b are provided to extend in a direction (left and right direction in FIG. 7) orthogonal to the alignment direction of the back surface land portion 14b. That is, since the extended land portions 30a and 30b are provided on the moving path of the heating iron portion 38 at the time of draw soldering, the leading end surface of the heating iron portion 38 is extended at the time of draw soldering. Land part 30a,
30b. Therefore, the extended land portions 30 a and 30 b are heated by the heating iron portion 38. Here, the extended land portions 30a and 30b extend with a length dimension L3 that is equal to or larger than the outer diameter dimension of the through hole 12, and are sufficient for the entire region of the front end surface of the heating iron portion 38 to abut. The size is assumed. Further, as shown in FIG. 7, the solder 42 is absorbed over substantially the whole of the extended land portions 30a and 30b, and the solder fillet 44 extends and widens compared to the alignment direction shown in FIG. Is formed.

  As shown in FIG. 2, a pair of extended land portions 34a and 34b provided in the dummy land portions 24a and 24b and a pair of extended land portions 36a and 36b provided in the intermediate dummy land portion 26 are also provided. Further, since they are provided so as to extend in a direction orthogonal to the alignment direction of the back surface land portion 14b (the left-right direction in FIG. 7), the tip of the heating iron 38 is also moved when the heating iron 38 is moved. It comes into contact with the surface and is heated.

  In the printed circuit board 10 according to the present embodiment configured as described above, the intermediate dummy land portion 26 extending between the end point side end portion of the first land row 22a and the start point side end portion of the second land row 22b. Therefore, the drawing solder can be continuously performed from the start point side end portion of the first land row 22a to the end point side end portion of the second land row 22b through the intermediate dummy land portion 26. . Therefore, the drawing soldering is temporarily interrupted between the first land row 22a and the second land row 22b, and the heating iron 38 is lifted onto the printed circuit board 10 and moved to the second land row 22b. It becomes unnecessary, and the workability of soldering by drawing solder can be improved.

  Further, since the heating iron portion 38 can be placed on the intermediate dummy land portion 26 and moved along the extending direction of the intermediate dummy land portion 26, excess solder is absorbed by the intermediate dummy land portion 26. However, the heating temperature of the heating iron 38 and the necessary amount of solder can be stably maintained, the formation of a solder bridge on the end point side of the first land row 22a, and the starting point of the second land row 22b. Occurrence of problems such as insufficient solder on the side can be advantageously prevented.

  Further, in the present embodiment, the intermediate dummy land portion 26 is provided between the first land row 22a and the second land row 22b, and these are arranged in a straight line. The first land row 22a and the second land row 22b can be soldered continuously by only a simple operation of moving the heating iron portion 38 linearly along the alignment direction of the land portions 14. It is possible to further stabilize and improve the efficiency of the soldering work.

  Further, in the present embodiment, the extended land portions 36a and 36b of the intermediate dummy land portion 26 are provided adjacent to the end portion on the end point side of the first land row 22a where surplus solder is likely to be a problem. Therefore, when the soldering of the first land row 22a is finished, the heating iron portion 38 is moved to the intermediate dummy land portion 26, and the surplus solder can be quickly absorbed by the extended land portions 36a and 36b. it can. In particular, the extended land portions 36 a and 36 b extend perpendicular to the extending direction of the intermediate dummy land portion 26, that is, the moving direction of the heating iron portion 38. It will be in contact and heated. Thereby, the excess solder that has contacted the extended land portions 36a and 36b is maintained at a relatively high temperature, and the excess solder can be quickly absorbed by the extended land portions 36a and 36b.

  In addition, the heating iron portion 38 is slid on the intermediate dummy land portion 26 without interrupting the pulling soldering operation when moving from the first land row 22a to the second land row 22b, so that the first land row 22a Since it can be continuously soldered from the starting point side end part to the terminal side end part of the second land row 22b, the heating state and the solder supply state of the heating iron part 38 can be stabilized. Accordingly, even when lead-free solder having a high melting point is used, soldering by pull solder can be performed continuously in a stable state from the first land row 22a to the second land row 22b, and the solder viscosity is reduced. It is possible to advantageously prevent the occurrence of problems such as insufficient solder supply.

  In the printed circuit board 10 according to the present embodiment, the extended land portions 30a and 30b that extend in a direction orthogonal to the alignment direction with respect to the plurality of aligned rear surface land portions 14b that are soldered by pull soldering. Are connected. Therefore, when the amount of the solder 42 supplied from the heating iron 38 is excessive, the excess solder is quickly absorbed into the extended land portions 30a and 30b and absorbed, and the excess solder is adjacent. Problems such as forming a solder bridge by connecting the back surface land portions 14b and 14b can be avoided. Further, since the extended land portions 30a and 30b are heated by the heating iron portion 38 during the pull soldering, the solder 42 supplied onto the back surface land portion 14b can be maintained at a relatively high temperature. The increase in the viscosity of the solder 42 itself can be prevented or reduced. Therefore, excess solder can be quickly absorbed by the extended land portions 30a, 30b, and the adjacent solder fillets 44, 44 are well divided by the surface tension, effectively preventing the occurrence of problems such as solder bridges. it can.

  As mentioned above, although embodiment of this invention was explained in full detail, this invention is not limited by the specific description, For example, various changes like the following are possible. In addition, in the following description, about the member and site | part similar to the said embodiment, the description is abbreviate | omitted by attaching | subjecting the same code | symbol in a figure.

  In the above embodiment, the first land row 22a and the second land row 22b are aligned on a straight line. However, the land rows are not necessarily aligned on a straight line. For example, as shown in FIG. 8, when the alignment directions of the land rows are on different straight lines, the land rows extend like the intermediate dummy land portions 48 so as to be inclined in the alignment direction. May be provided. Further, an intermediate dummy land portion 50 extending in a curved manner between the land rows may be provided so that the drawing solder is continuously performed between the land rows orthogonal to each other.

  In the above-described embodiment, the extended land portions 36 a and 36 b connected to the intermediate dummy land portion 26 are provided so as to extend on both sides in the direction orthogonal to the alignment direction. For example, the extended land portion may be provided only on one side in the direction orthogonal to the alignment direction.

  In addition, the specific shapes of the back surface land portion 14b, the extended land portions 30a, 30b, 34a, 34b, 34c, 36a, 36b, the dummy land portions 24a, 24b, and the intermediate dummy land portion 26 are limited to those of the above embodiment. Any shape can be adopted as long as the object of the present invention can be achieved. For example, the length dimension L4 of the extended land portions 34a, 34b, and 34c of the dummy land portions 24a and 24b and the length dimension L6 of the extended land portions 36a and 36b of the intermediate dummy land portion 26 are the back surface land portion 14b. The length dimensions of the extended land portions 30a and 30b need not be equal to L2, and can be made smaller or larger in consideration of the empty space of the printed circuit board, the amount of excess solder, and the like. Further, the intersecting angle of the extended land portions 30a, 30b, 34a, 34b with respect to the alignment direction of the back surface land portion 14b can be appropriately changed.

  10: Printed circuit board, 12: Through hole, 14: Land portion, 16a, b: Mounted part, 20: Lead portion, 22a: First land row, 22b: Second land row, 26: Intermediate dummy land portion, 36a, b: Extension land

Claims (4)

A plurality of land portions provided in the through holes are arranged and arranged, and lead portions of the mounting parts are inserted into the through holes of the plurality of land portions, and the land portions and the lead portions are soldered by drawing solder. In the attached printed circuit board,
A first land row composed of a plurality of land portions arranged in a group and a second land row composed of a plurality of land portions arranged in another group are spaced apart from each other. While being
An intermediate dummy land portion extending between an end of the first land row on the end solder side of the draw solder and an end of the second land row on the start point side of the draw solder is provided. Characteristic printed circuit board.   The first land row and the second land row are arranged in a straight line at intervals in the alignment direction of the plurality of land portions, and between the first land row and the second land row. The printed circuit board according to claim 1, wherein the intermediate dummy land portion extending in the alignment direction is provided.   2. An extended land portion extending on both sides in a direction intersecting with an extending direction of the intermediate dummy land portion is connected to an end portion on the first land row side of the intermediate dummy land portion. Or the printed circuit board of 2.   The printed circuit board according to claim 1, wherein the land portion and the lead portion are soldered by the pull solder using lead-free solder.

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