JP2018125458A - Printed wiring board - Google Patents

Abstract

The present invention provides a printed wiring board that can sufficiently reduce stress applied to solder joints that connect a sub-board to a main board. A printed wiring board 1 includes a main board 2, a sub board 3, and a reinforcing board 4. The main substrate 2 has a front surface 2a, a back surface 2b, a main slit 20, and a main electrode 20a. The sub-substrate 3 has a front surface 3a, a back surface 3b, and a sub-electrode 3c. The reinforcing board 4 is supported by the main board 2. Reinforcement board 4 includes a notch 40 . The cutout 40 has a first side 40a, a second side 40b, and a bottom 40c. The upper part of the sub-board 3 is in contact with the bottom part 40c of the notch 40. The lower part of the sub-board 3 is inserted into the main slit 20. The main electrode 20a is connected to the sub-electrode 3c by a solder joint. [Selection diagram] Figure 3

Description

  The present invention relates to a printed wiring board, and particularly to a printed wiring board including a main board and a sub board.

  Conventionally, a printed wiring board in which a sub-board is inserted into a slit provided in a main board is used. The electrodes on the main board are connected to the electrodes on the sub board by solder joints. Such a printed wiring board is described in, for example, Japanese Patent Application Laid-Open No. 2008-171849 (Patent Document 1). The printed wiring board described in this publication is provided with a reinforcing plate for assisting the self-supporting of the sub-board.

JP 2008-171849 A

  In the printed wiring board described in the above publication, the reinforcing plate is engaged with the lower portion of the sub-board. Therefore, when vibration is applied to the printed wiring board, there is a problem in that the stress applied to the solder joint portion connecting the main board and the sub board by the reinforcing board cannot be sufficiently reduced.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a printed wiring board capable of sufficiently reducing the stress applied to the solder joint portion connecting the sub board to the main board.

  The printed wiring board of the present invention includes a main board, a sub board, and a reinforcing board. The main substrate has a front surface, a back surface, a slit penetrating from the front surface to the back surface, and a first electrode provided on the back surface. The sub-board has a front surface, a back surface, and a second electrode provided on the front surface. The reinforcing substrate is supported on the main substrate. The reinforcing substrate includes a notch. The notch has first and second side surfaces sandwiching the front surface and the back surface of the sub-board, and a bottom portion connecting the first and second side surfaces. The upper part of the sub-board is in contact with the bottom of the notch. The lower part of the sub-board is inserted into the slit. The first electrode is connected to the second electrode by a solder joint.

  According to the printed wiring board of the present invention, the reinforcing substrate includes a notch having first and second side surfaces sandwiching the front surface and the back surface of the sub substrate, and a bottom portion connecting the first and second side surfaces. For this reason, when a vibration is applied to the printed wiring board, it is possible to reduce the vibration in the direction of sandwiching the front surface and the back surface of the sub-board by the first and second side surfaces. And since the upper part of a sub board | substrate is contact | abutting to the bottom part of a notch, it can support to the upper part of a sub board | substrate by a bottom part. Thereby, the stress applied to the solder joint that connects the second electrode of the sub-board to the first electrode of the main board can be sufficiently reduced.

It is a perspective view which shows roughly the structure of the printed wiring board in Embodiment 1 of this invention. It is a front view which shows roughly the structure of the printed wiring board in Embodiment 1 of this invention. It is a disassembled perspective view which shows roughly the structure of the printed wiring board in Embodiment 1 of this invention. It is a side view which shows roughly the structure of the printed wiring board in Embodiment 1 of this invention. It is a schematic sectional drawing for demonstrating the manufacturing method of the printed wiring board in Embodiment 1 of this invention. It is a side view which shows roughly the structure of the printed wiring board in the modification of Embodiment 1 of this invention. It is a side view which shows roughly the structure of another printed wiring board in the modification of Embodiment 1 of this invention. It is a perspective view which shows roughly the structure of the printed wiring board in Embodiment 2 of this invention. It is a disassembled perspective view which shows schematically the structure of the printed wiring board in Embodiment 2 of this invention. It is a perspective view which shows roughly the structure of the printed wiring board in the modification of Embodiment 2 of this invention. It is a top view which shows roughly the structure of the printed wiring board in the modification of Embodiment 2 of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
Embodiment 1 FIG.
With reference to FIGS. 1-4, the structure of the printed wiring board 1 in Embodiment 1 of this invention is demonstrated. The printed wiring board 1 of the present embodiment is a three-dimensional printed wiring board. FIG. 1 is a perspective view showing a printed wiring board 1 of the present embodiment. FIG. 2 is a front view showing the printed wiring board 1 of the present embodiment. FIG. 3 is an exploded perspective view showing the printed wiring board 1 of the present embodiment. FIG. 4 is a side view showing the printed wiring board 1 of the present embodiment. In FIG. 2 to FIG. 4, electronic components are not shown for convenience of explanation. 3 and 4, the solder joint is not shown for convenience of explanation.

  As shown in FIGS. 1 and 2, the printed wiring board 1 of the present embodiment mainly includes a main board 2, a sub board 3, a reinforcing board 4, and a solder joint portion 5. Electronic components such as an electrolytic capacitor 10, a chip capacitor 11, a chip resistor 12, a transformer 13, and a power semiconductor 14 are mounted on the main substrate 2 and the sub substrate 3 by soldering. The power semiconductor 14 may be equipped with a heat sink (heat radiator).

  Each of the main board 2, the sub board 3, and the reinforcing board 4 is made of a general printed wiring board material. Specifically, the main substrate 2 is a laminated body using, for example, a glass nonwoven fabric in which a core of a base material is impregnated with a flame retardant epoxy resin, and a glass cloth and an epoxy resin prepreg on the surface for the purpose of reinforcing the strength. It is comprised from CEM-3 (Composite epoxy material-3) which is a board.

  As shown in FIG. 2 and FIG. 3, the main substrate 2 includes a front surface 2a, a back surface 2b, a main slit (slit) 20, a main electrode (first electrode) 20a, a reinforcing slit 21, and a main reinforcing electrode. 21a. Electronic components such as the electrolytic capacitor 10 are mounted on the surface 2 a of the main substrate 2.

  The main slit 20 and the reinforcing slit 21 are provided so as to penetrate from the front surface 2a to the back surface 2b, respectively. In the present embodiment, a plurality of reinforcing slits 21 are provided. Specifically, two reinforcing slits 21 are provided. The two reinforcing slits 21 are arranged so as to intersect the main slit 20. In the present embodiment, the two reinforcing slits 21 are arranged so as to be orthogonal to the main slit 20. The main slit 20 and the reinforcing slit 21 may be provided by pressing with a mold.

  A main electrode 20a and a main reinforcing electrode 21a are provided on the back surface 2b of the main substrate 2, respectively. In the present embodiment, a plurality of main electrodes 20a and a plurality of main reinforcing electrodes 21a are provided on the back surface 2b. The plurality of main electrodes 20a and the plurality of main reinforcing electrodes 21a are arranged in the longitudinal direction of the main slit 20 at regular intervals. The plurality of main electrodes 20a and the plurality of main reinforcing electrodes 21a are arranged so as to be connected to the main slit 20, respectively. The plurality of main electrodes 20 a and the plurality of main reinforcing electrodes 21 a are respectively disposed in the short direction of the main slit 20 with the main slit 20 interposed therebetween.

  The sub board 3 is supported by the main board 2 so as to rise from the surface 2 a of the main board 2. The sub-substrate 3 includes a front surface 3a, a back surface 3b, a sub-electrode (second electrode) 3c, a concave portion 30, a main body portion 31, and a support portion 32. Electronic components such as an electrolytic capacitor 10, a chip capacitor 11, a chip resistor 12, a transformer 13, and a power semiconductor 14 are mounted on the front surface 3 a of the sub-substrate 3.

  A sub electrode 3 c is provided on the front surface 3 a of the sub substrate 3. Although not shown, the sub-electrode 3 c is also provided on the back surface 3 b of the sub-substrate 3. In the present embodiment, a plurality of sub-electrodes 3c are provided on both the front surface 3a and the back surface 3b.

  The main body portion 31 projects from the support portion 32 in the longitudinal direction of the sub-board 3. That is, the main body portion 31 protrudes from the support portion 32 on both sides on one side and the other side of the sub-board 3. A step is formed by the main body portion 31 and the support portion 32. The main body 31 protrudes on both sides of the main slit 20 in the longitudinal direction of the main slit 20. Electronic parts such as an electrolytic capacitor 10, a chip capacitor 11, a chip resistor 12, a transformer 13, and a power semiconductor 14 are mounted on the main body 31.

  The support portion 32 is provided so as to protrude downward from the main body portion 31 at the lower portion of the sub-board 3. The plurality of sub-electrodes 3 c are provided on the support portion 32. The plurality of sub-electrodes 3 c are arranged at equal intervals in the longitudinal direction of the sub-substrate 3.

  The support portion 32 is inserted into the main slit 20. Each of the plurality of sub-electrodes 3c is disposed at a position corresponding to each of the plurality of main electrodes 20a. Each of the plurality of main electrodes 20a is connected to each of the plurality of sub-electrodes 3c by solder joints 5. The main board 2 and the sub board 3 are electrically connected by soldering the plurality of main electrodes 20a to the plurality of sub electrodes 3c.

  The lower surfaces of the one end portion and the other end portion of the main body portion 31 projecting from the support portion 32 on both sides on one side and the other side of the sub substrate 3 are in contact with the surface 2 a of the main substrate 2. The lower surfaces of the one end and the other end of the main body 31 constitute a contact portion 33. When the contact portion 33 contacts the surface 2a of the main substrate 2, the insertion depth of the support portion 32 into the main slit 20 is determined.

  In the present embodiment, the upper portion of the sub-board 3 includes a recess 30. The recess 30 is configured to be recessed from the upper end to the lower end of the sub-board 3. The recess 30 has a bottom surface 30a and two side surfaces 30b. The side surface 30b is configured to rise from both ends of the bottom surface 30a. The concave portion 30 is disposed on the inner side of the one end portion and the other end portion of the sub substrate 3. That is, the upper surface of the sub substrate 3 is provided on both sides of the recess 30 in the longitudinal direction of the sub substrate 3. The reinforcing substrate 4 is fitted into the recess 30. In the present embodiment, two recesses 30 are provided. The two concave portions 30 are provided on one side and the other side of the sub-substrate 3 respectively.

  The recess 30 is disposed immediately above the support portion 32. That is, the recesses 30 are not disposed at both ends of the main body 31 protruding from the support portion 32 on both sides of the sub-board 3 on one side and the other side. Therefore, the reinforcing substrate 4 can hold the sub substrate 3 toward the main substrate 2 in the region directly above the support portion 32 inserted into the main slit 20. As a result, the sub-board 3 can be firmly held on the main board 2 by the reinforcing board 4.

  The reinforcing substrate 4 is supported by the main substrate 2. The reinforcing substrate 4 has a first surface 4a, a second surface 4b, a reinforcing electrode 4c, and a notch 40. The reinforcing electrode 4 c is provided at the lower part of the reinforcing substrate 4. The reinforcing electrode 4c is provided on both the first surface 4a of the reinforcing substrate 4 and the second surface 4b opposite to the first surface 4a. In the present embodiment, a plurality of reinforcing electrodes 4c are provided on each of the first surface 4a and the second surface 4b. Specifically, the plurality of reinforcing electrodes 4c are provided on each of the first surface 4a and the second surface 4b. Each of the plurality of reinforcing electrodes 4 c is connected to each of the plurality of main reinforcing electrodes 21 a by solder joints 5.

  The notch 40 has a first side surface 40a, a second side surface 40b, and a bottom (deep portion) 40c. The first side surface 40a and the second side surface 40b are arranged to face each other. The first side surface 40 a and the second side surface 40 b are configured so as to sandwich the front surface 3 a and the back surface 3 b of the sub substrate 3. The bottom portion 40c is configured to connect the first side surface 40a and the second side surface 40b. The notch 40 is formed from the lower surface to the upper surface of the reinforcing substrate 4. The reinforcing substrate 4 is configured in a substantially U shape. The concave portion 30 of the sub-substrate 3 is fitted into the bottom portion 40c. Specifically, the bottom 40 c of the notch 40 is placed on the bottom surface 30 a of the recess 30. Further, the first surface 4 a and the second surface 4 b of the reinforcing substrate 4 are in contact with the two side surfaces 30 b of the recess 30.

  As shown in FIGS. 2 and 4, the first side surface 40 a of the notch 40 is in contact with the front surface 3 a of the sub-board 3. The second side surface 40 b of the notch 40 is in contact with the back surface 3 b of the sub substrate 3. The upper part of the sub-board 3 is in contact with the bottom 40c of the notch 40. The upper part of the sub-board 3 is above the center in the height direction of the sub-board 3. The lower part of the sub-board 3 is inserted into the main slit 20. Specifically, a support portion 32 provided at the lower portion of the sub-board 3 is inserted into the main slit 20.

  In the present embodiment, the reinforcing substrate 4 includes a first reinforcing substrate 41 and a second reinforcing substrate 42. The 1st reinforcement board | substrate 41 and the 2nd reinforcement board | substrate 42 are comprised similarly. The first reinforcing substrate 41 is disposed on one side of the sub substrate 3 in the longitudinal direction. The second reinforcing substrate 42 is disposed on the other side in the longitudinal direction of the sub-substrate 3.

Next, with reference to FIG. 5, the manufacturing method of the printed wiring board of this Embodiment is demonstrated.
As shown in FIG. 5, the main electrode 20a, the main reinforcing electrode 21a, the sub electrode 3c, and the reinforcing electrode 4c are inserted into the main slit 20 and the reinforcing slit 21 with the support portion 32 and the reinforcing substrate 4 inserted vertically. Are soldered together.

  The support portion 32 of the sub board 3 is inserted into the main slit 20 of the main board 2. At this time, the contact depth 33 of the sub-board 3 comes into contact with the surface 2a of the main board 2 so that the insertion depth of the sub-board 3 into the main slit 20 is determined. The reinforcing substrate 4 is inserted into the reinforcing slit 21 while fitting the recess 30 of the sub-substrate 3 into the notch 40. At this time, the insertion depth of the reinforcing substrate 4 into the reinforcing slit 21 is determined by the depth of the notch 40 that contacts the upper portion of the sub-substrate 3.

  For example, the main electrode 20a, the main reinforcing electrode 21a, the sub electrode 3c, and the reinforcing electrode 4c are soldered together by a flow soldering method in which they are immersed in a molten solder jet and soldered. Thereby, the main electrode 20a and the main reinforcing electrode 21a and the sub electrode 3c and the reinforcing electrode 4c are soldered and fixed.

  Specifically, the molten solder 6 stored in the solder bath 200 is transmitted from the flow soldering nozzle 201 by the driving force of the motor 202 being transmitted to the propeller 204 via the motor shaft 203 and rotating the propeller 204. Jet upward. The back surface 2b of the main board 2 is disposed above the flow soldering nozzle 201. The back surface 2b of the main board 2 is immersed in the jet solder. Thereby, the main electrode 20a and the main reinforcement electrode 21a, the sub electrode 3c, and the reinforcement electrode 4c are soldered, respectively.

  In the method for manufacturing the printed wiring board 1 of the present embodiment, the sub board 3 and the reinforcing board 4 are inserted into the main board 2 after the sub board 3 and the reinforcing board 4 are inserted into the main slit 20 and the reinforcing slit 21 of the main board 2. Are joined. For this reason, the inclination of the sub board | substrate 3 and the reinforcement board | substrate 4 can be suppressed. Moreover, the joining process can be reduced.

Next, the effect of the printed wiring board 1 of this Embodiment is demonstrated.
According to the printed wiring board 1 of the present embodiment, when vibration is applied to the printed wiring board 1, the front surface 3 a and the back surface 3 b of the sub-board 3 are connected by the first side surface 40 a and the second side surface 40 b of the notch 40. Vibration in the sandwiching direction can be reduced. Since the upper portion of the sub substrate 3 is in contact with the bottom portion 40c of the notch 40, the bottom portion 40c can support the upper portion of the sub substrate 3. Thereby, the stress concerning the solder joint part 5 which connects the sub electrode 3c of the sub board | substrate 3 to the main electrode 20a of the main board | substrate 2 can fully be reduced.

  In addition, since the stress applied to the solder joint 5 connecting the sub electrode 3c of the sub board 3 to the main electrode 20a of the main board 2 can be sufficiently reduced, large components such as the transformer 13 can be mounted on the sub board 3. It becomes possible. At this time, as the large component such as the transformer 13 mounted on the sub-board 3 is mounted at a position closer to the solder joint 5 between the main board 2 and the sub-board 3, the warp of the sub-board 3 due to vibration can be reduced. it can.

  According to the printed wiring board 1 of the present embodiment, the recess 30 at the top of the sub-board 3 is fitted into the bottom 40c. As a result, the reinforcing substrate 4 is held in the concave portion 30 of the sub-substrate 3, so that the sub-substrate 3 can be firmly held by the reinforcing substrate 4.

  In the present embodiment, the recess 30 is provided on the upper portion of the sub-substrate 3, but the recess 30 may not be provided. Even in this case, the same effect as the effect of the present embodiment can be obtained.

  According to the printed wiring board 1 of the present embodiment, at least one of the transformer 13, the capacitor (the electrolytic capacitor 10 and the chip capacitor 11), and the power semiconductor 14 is mounted on the sub-board 3. For this reason, even when the vibration of the sub-substrate 3 becomes large, the vibration of the sub-substrate 3 can be effectively reduced by the reinforcing substrate 4. In particular, since the transformer 13 is heavy, even if the vibration of the sub-board 3 is particularly increased by mounting the transformer 13 on the sub-board 3, the vibration of the sub-board 3 is effectively reduced by the reinforcing board 4. Can be reduced.

  In this embodiment, an example in which two reinforcing substrates 4 are used is shown, but one or three or more reinforcing substrates 4 may be used. Even in this case, the same effect as the effect of the present embodiment can be obtained.

  Next, various modifications of the present embodiment will be described with reference to FIGS. Note that the various modifications of the present embodiment have the same configuration as that of the present embodiment unless otherwise described, and therefore, the same components are denoted by the same reference numerals and the description thereof is not repeated. . The various modifications of the present embodiment differ from the above-described present embodiment in the shape of the notch 40.

  As shown in FIG. 6, in the first modification of the present embodiment, when the reinforcing substrate 4 is viewed from the direction along both the front surface 2a and the front surface 3a of the main substrate 2, the bottom 40c of the notch 40 is It has an arc shape. Specifically, the bottom 40c is formed in an arc shape that protrudes upward. The corners at both ends of the upper portion of the sub-substrate 3 are in contact with the arc shape of the bottom portion 40c.

  As shown in FIG. 7, in the second modification of the present embodiment, when the reinforcing substrate 4 is viewed from the direction along both the front surface 2a and the front surface 3a of the main substrate 2, the bottom 40c of the notch 40 is It has a triangular shape. Specifically, the bottom 40c is formed so that the width becomes narrower upward. The corners at both ends of the upper portion of the sub-substrate 3 are in contact with the triangular shape of the bottom portion 40c.

  The width of the cutout 40 of the reinforcing substrate 4 and the thickness of the sub-substrate 3 have dimensional tolerances. For this reason, a gap may be formed between the notch 40 of the reinforcing substrate 4 and the sub substrate 3 depending on the dimensional tolerance of the width of the notch 40 of the reinforcing substrate 4 and the thickness of the sub substrate 3. Even in such a case, according to Modification 1 and Modification 2 of the present embodiment, the corners at both ends of the upper portion of the sub-board 3 can be reliably brought into contact with the bottom 40c. For this reason, the sub board | substrate 3 and the reinforcement board | substrate 4 can be reliably fitted by the bottom part 40c.

Embodiment 2. FIG.
In the second embodiment of the present invention, the same components as those of the first embodiment of the present invention described above are provided unless otherwise described. Therefore, the same reference numerals are given to the same elements, and the description thereof is not repeated. .

  With reference to FIG. 8 and FIG. 9, the structure of the printed wiring board 1 in Embodiment 2 of this invention is demonstrated. FIG. 8 is a perspective view showing the printed wiring board 1 of the present embodiment. FIG. 9 is an exploded perspective view showing the printed wiring board 1 of the present embodiment. In FIGS. 8 and 9, electronic components are not shown for convenience of explanation.

  In the second embodiment of the present invention, the configuration of the reinforcing substrate 4 is mainly different from that in the first embodiment. In the present embodiment, electronic components such as an electrolytic capacitor 10, a chip capacitor 11, a chip resistor 12, a transformer 13, and a power semiconductor 14 are mounted on the reinforcing substrate 4 by soldering.

  The reinforcing slit 21 is disposed so as to intersect the main slit 20 at the center in the longitudinal direction of the main slit 20. The reinforcing substrate 4 is disposed at the center in the longitudinal direction of the sub-substrate 3. Further, the notch 40 of the reinforcing substrate 4 is disposed at the center in the longitudinal direction of the reinforcing substrate 4.

Next, the effect of the printed wiring board 1 of this Embodiment is demonstrated.
According to the printed wiring board 1 of the present embodiment, electronic components such as the electrolytic capacitor 10, the chip capacitor 11, the chip resistor 12, the transformer 13, and the power semiconductor 14 can be mounted on the reinforcing substrate 4. 1 can be further downsized.

  In the present embodiment, since the reinforcing substrate 4 is not provided with the contact portion 33 of the sub-substrate 3, the bottom 40 c of the notch 40 is in contact with the upper portion of the sub-substrate 3 to ensure vibration resistance. Can be improved. The reinforcing substrate 4 may be provided with a contact portion similar to the contact portion 33 of the sub-substrate 3. Even in this case, by adjusting the height of the contact portion of the reinforcing substrate 4 so that the bottom portion 40c of the notch 40 is in contact with the upper portion of the sub-substrate 3, the vibration resistance is improved and the reinforcing substrate 4 is fixed at the contact portion. It can be held on the surface 2 a of the main substrate 2.

  Next, a modification of the present embodiment will be described with reference to FIGS. 10 and 11. In addition, since the modification of this Embodiment is provided with the structure similar to said this Embodiment unless it demonstrates especially, the same code | symbol is attached | subjected about the same element and the description is not repeated. The modification of the present embodiment is different from the above-described embodiment in the number of sub-substrates 3 and reinforcing substrates 4.

  As shown in FIG. 10, the sub board 3 includes a first sub board 3x and a second sub board 3y. The first sub board 3x and the second sub board 3y are arranged in parallel to each other. The reinforcing substrate 4 includes a first reinforcing substrate 41 and a second reinforcing substrate 42. The 1st reinforcement board | substrate 41 and the 2nd reinforcement board | substrate 42 are mutually arrange | positioned in parallel. The first sub-board 3x, the second sub-board 3y, the first reinforcing board 41, and the second reinforcing board 42 have different electrolytic capacitors 10, chip capacitors 11, chip resistors 12, transformers 13, power semiconductors 14 and other electronic components. Is mounted by soldering.

  The notch 40 of the first reinforcing substrate 41 includes a first notch 401 and a second notch 402. The first notch 401 is disposed on the first side in the longitudinal direction of the first reinforcing substrate 41, and the second notch 402 is disposed on the second side in the longitudinal direction of the first reinforcing substrate 41. The first reinforcing substrate 41 extends over the first sub substrate 3x and the second sub substrate 3y. The cutout 40 of the second reinforcing substrate 42 includes a third cutout 403 and a fourth cutout 404. The third notch 403 is disposed on the first side in the longitudinal direction of the second reinforcing substrate 42, and the fourth notch 403 is disposed on the second side in the longitudinal direction of the second reinforcing substrate 42. The second reinforcing substrate 42 extends over the first sub substrate 3x and the second sub substrate 3y.

  The first sub board 3x is inserted into both the first notch 401 of the first reinforcing board 41 and the third notch 403 of the second reinforcing board 42. The second sub board 3y is inserted into both the second notch 402 of the first reinforcing board 41 and the fourth notch 404 of the second reinforcing board 42. One side of each of the first sub board 3x and the second sub board 3y is held by the first reinforcing board 41, and the other side of each of the first sub board 3x and the second sub board 3y is held by the second reinforcing board 42. Has been.

  As shown in FIG. 11, a power semiconductor 14 such as a MOSFET (metal oxide semiconductor field effect transistor) is mounted on the reinforcing substrate 4. A heat sink (heat radiator) 15 is attached to the power semiconductor 14. The power semiconductor 14 and the heat sink 15 are surrounded by the first sub board 3x, the second sub board 3y, the first reinforcing board 41, and the second reinforcing board 42.

  A through hole 22 is provided in the main substrate 2. The through hole 22 is arranged at the center of the region surrounded by the first sub-board 3x, the second sub-board 3y, the first reinforcing board 41, and the second reinforcing board 42 when the surface 2a of the main board 2 is viewed from above. Has been.

  According to the modification of the present embodiment, since the sub board 3 includes the first sub board 3x and the second sub board 3y, the solder joints 5 between the main board 2 and the sub board 3 can be dispersed. it can. For this reason, when the vibration is applied to the printed wiring board 1, the stress applied to the solder joint portion 5 can be dispersed. Thereby, the reliability of the solder joint part 5 can be improved.

  The first reinforcing substrate 41 and the second reinforcing substrate 42 extend over the first sub substrate 3x and the second sub substrate 3y, respectively. For this reason, the 1st sub board | substrate 3x and the 2nd sub board | substrate 3y can be hold | maintained firmly.

  The power semiconductor 14 mounted on the reinforcing substrate 4 is disposed inside a region surrounded by the first sub substrate 3x, the second sub substrate 3y, the first reinforcing substrate 41, and the second reinforcing substrate 42. Therefore, it is possible to suppress the heat of the power semiconductor 14 from being transmitted to the electronic component mounted on the main board 2 outside the region.

  Further, since the through hole 22 is provided in the main substrate 2, it is possible to generate an updraft due to heat generated by the power semiconductor 14 in the region. For this reason, wind is taken into the area from the back surface 2 b of the main board 2. The effect of cooling the heat sink 15 by this wind can be improved.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  DESCRIPTION OF SYMBOLS 1 Printed wiring board, 2 main board, 2a surface, 2b back surface, 3 sub board | substrate, 3a front surface, 3b back surface, 3c sub electrode, 3x 1st sub board | substrate, 3y 2nd sub board | substrate, 4 reinforcement board | substrate, 4a 1st surface, 4b Second surface, 4c Reinforcing electrode, 5 Solder joint, 10 Electrolytic capacitor, 11 Chip capacitor, 12 Chip resistor, 13 Transformer, 14 Power semiconductor, 15 Heat sink, 20 Main slit, 20a Main electrode, 21 Reinforcing slit, 21a Main Reinforcing electrode, 22 Through hole, 30 Recessed part, 31 Main body part, 32 Support part, 33 Contact part, 40a First side face, 40b Second side face, 40c Bottom part, 41 First reinforcing board, 42 Second reinforcing board, 200 Solder bath 201 Flow soldering nozzle, 202 motor, 203 motor shaft, 204 prop .

Claims (5)

A main substrate having a front surface, a back surface, a slit penetrating from the front surface to the back surface, and a first electrode provided on the back surface;
A sub-board having a front surface, a back surface, and a second electrode provided on the front surface;
A reinforcing substrate supported by the main substrate,
The reinforcing substrate includes a notch having first and second side surfaces sandwiching the front surface and the back surface of the sub-substrate, and a bottom portion connecting the first and second side surfaces,
The top of the sub-board is in contact with the bottom of the notch,
The lower part of the sub-board is inserted into the slit,
The printed wiring board, wherein the first electrode is connected to the second electrode by a solder joint. The upper part of the sub-board includes a recess that is recessed from the upper end to the lower end of the sub-board,
The printed wiring board according to claim 1, wherein the concave portion is fitted to the bottom portion.   The printed wiring board according to claim 1, wherein when the reinforcing substrate is viewed from a direction along both the front surface and the front surface, the bottom portion has one of an arc shape and a triangular shape. The sub-board includes a first sub-board and a second sub-board,
The reinforcing substrate includes a first reinforcing substrate and a second reinforcing substrate,
The notch of the first reinforcing substrate includes a first notch and a second notch,
The notch of the second reinforcing substrate includes a third notch and a fourth notch,
The first sub-board is inserted into both the first notch and the third notch,
The printed wiring board according to claim 1, wherein the second sub-board is inserted into both the second cutout and the fourth cutout. The printed wiring board according to claim 1, wherein at least one of a transformer, a capacitor, and a power semiconductor is mounted on the sub-board.

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