JP2006237176A - Connection structure of printed circuit board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a connection structure of a printed circuit board which can reduce stress to be applied to a soldered portion between printed circuit boards when force is applied in a direction of separating the printed circuit boards from each other. <P>SOLUTION: The connection structure of a printed circuit board is for connecting a daughter board 1 including a connection piece 11 formed with first connection patterns 30 to a mother board 2 which has a connection hole 21 to insert the connection piece 11, and formed with second connection patterns 31 to be soldered to the first connection patterns 30 in the periphery of the connection hole 21. The connection piece 11 includes a projecting portion 11b which will abut against the periphery of the connection hole 21 on the rear surface side of the mother board 2, when the connection piece 11 is moved in a direction crossing the insertion direction of the connection piece 11 within the connection hole 21 to position the first connection patterns 30 to predetermined places with respect to the second connection patterns 31. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a printed circuit board connection structure for electrically and mechanically connecting a plurality of printed circuit boards.

  Conventionally, a printed circuit board (mother board) on which various integrated circuits and other circuit components are mounted and a printed circuit board (child board) constituting a hybrid integrated circuit (HIC), for example, electrically and mechanically Connecting is done.

  As a connection structure of a printed circuit board for electrically and mechanically connecting such a mother board and a child board, as shown in FIGS. 11A and 11B, one end portion (lower end portion) of the child board 100 is used. A plurality of external terminals 300 protruding from the mother board 200 are inserted into through holes (not shown) of the mother board 200 and soldered by the solder 400 on the back surface side of the mother board 200. As shown in FIG. 11C, a substrate 200 is accommodated in a case 500, and the case 500 is filled with a resin 600.

  On the other hand, as shown in FIG. 12A, a connection piece 102 protruding from one end edge (lower end edge) of the sub board 101 and having a connection pattern 301 formed is inserted into the connection hole 202 of the mother board 201 to connect the connection pattern. 301 is soldered to a connection pattern (not shown) on the back side of the mother board 201, and the child board 101 and the mother board 201 soldered in this way are stored in a case 501 as shown in FIG. And what fills this case 501 with resin 601 is provided.

Furthermore, in addition to the configuration shown in FIG. 12, there is provided one provided with a positioning portion for positioning the sub board on the mother board so that the insertion position of the sub board on the mother board is not shifted (Patent Document 1). .
Japanese Utility Model Publication No. 7-7166 (FIG. 1)

  However, in the conventional printed circuit board connection structure as described above, the daughter board and the mother board are both electrically and mechanically connected by simply soldering in the insertion direction of the daughter board. Therefore, when a force in the pulling direction opposite to the insertion direction is applied to the child board, that is, when a force in the direction to separate the two boards is applied, this force is applied to the soldering part between the child board and the mother board. This causes problems such as peeling of the solder.

  SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and an object of the present invention is to provide a printed circuit that can reduce the stress applied to the soldered portion between the printed circuit boards when a force is applied to pull the printed circuit boards apart. It is to provide a board connection structure.

  In order to solve the above problems, in the printed circuit board connection structure according to claim 1, a first printed circuit board having a connection piece on which a first connection pattern is formed, and a connection hole through which the connection piece is inserted. And a second printed circuit board in which a second connection pattern soldered to the first connection pattern is formed on the peripheral edge of the connection hole, and provided on either the connection piece side or the connection hole side When the first connection pattern is positioned at a predetermined position with respect to the second connection pattern by moving the connection piece provided on the other side of the locking portion and the remaining other in the connection hole in the direction intersecting the insertion direction of the connection piece. It is comprised by the latching means provided with the to-be-latched part latched by the latching | locking part.

  According to the first aspect of the present invention, the first printed circuit board and the second printed circuit board are connected to each other by soldering and are locked to each other by the locking means. When a force is applied in the direction, a part of the force can be received by the locking means to reduce the force applied to the soldering site, thereby reducing the stress applied to the soldering site. be able to.

  In the printed circuit board connection structure of claim 2, in addition to the configuration of claim 1, the locked portion is formed on the connection piece so as to protrude in a direction orthogonal to the insertion direction of the first printed circuit board. The engaging portion is formed by a peripheral portion of a connection hole with which the protruding portion abuts.

  According to invention of Claim 2, the 1st printed circuit board and the 2nd printed circuit board are mutually latched by making the protrusion provided in the connection piece contact the peripheral part of a connection hole. Therefore, the stress applied to the soldering site can be reduced with a simple structure.

  In the printed circuit board connection structure according to claim 3, in addition to the configuration of claim 1, the locked portion includes a plurality of protrusions protruding from the inner surface of the connection hole, and the locking portion is connected It consists of a hole formed in a piece and into which a plurality of protrusions are respectively inserted.

  According to the invention of claim 3, the first printed circuit board and the second printed circuit board are inserted by inserting a plurality of protrusions projecting from the inner surface of the connection hole into the hole provided in the connection piece. Since the first printed circuit board and the second printed circuit board are engaged with each other, the number of engagement portions between the first printed circuit board and the second printed circuit board can be increased, whereby the stress applied to the soldering portion can be further reduced.

  In the printed circuit board connection structure according to claim 4, in addition to the configuration of any one of claims 1 to 3, the first printed circuit board connection piece is provided with a first dummy connection pattern, A second dummy connection pattern to be soldered to the first dummy connection pattern is provided at a peripheral portion of the connection hole of the second printed circuit board.

  According to the invention of claim 4, by soldering the dummy connection patterns provided on both printed circuit boards, the total area of the soldering part can be increased, whereby the stress applied to the soldering part is increased. Can be reduced.

  In the printed circuit board connection structure according to claim 5, in addition to the structure according to any one of claims 1 to 4, the solder used for soldering is lead-free solder which does not contain lead as a component. And

  According to the invention of claim 5, since lead-free solder is used, it is possible to comply with European RoHS directives and lead-free products such as the Japanese Home Appliance Recycling Law.

  In the printed circuit board connection structure of claim 6, in addition to the structure of any one of claims 1 to 5, both printed circuit boards are housed in a case, and the case is filled with resin. Features.

  According to invention of Claim 6, since both printed circuit boards are covered with resin, insulation, heat dissipation, and waterproofing can be improved.

  In the present invention, since the first printed circuit board and the second printed circuit board are connected by soldering and are locked to each other by the locking means, a force is applied in the direction of separating the two printed circuit boards. When this is done, there is an effect that a part of such force is received by the locking means, and the stress applied to the soldering site can be reduced.

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

(Embodiment 1)
As shown in FIGS. 1A and 1B, the printed circuit board connection structure of the present embodiment includes a first printed circuit board (hereinafter, referred to as a first printed circuit board having a connection piece 11 formed with a first connection pattern 30). The second connection pattern 31 having a connection hole 21 through which the connection piece 11 is inserted and a second connection pattern 31 to be soldered to the first connection pattern 30 is formed at the peripheral edge of the connection hole 21. The first connection pattern 30 is a connection structure for connecting to two printed circuit boards (hereinafter referred to as mother boards) 2, and the connection piece 11 is moved in the connection hole 21 in a direction crossing the insertion direction of the connection piece 11. Is provided on the connection piece 11 on the back surface side of the mother board 2 when it is positioned at a predetermined position with respect to the second connection pattern 31.

  The sub board 1 is, for example, a printed circuit board constituting a hybrid integrated circuit (HIC). As shown in FIG. 2A, a pair of connections is made to one end edge (lower end edge) of the insulating board 10 of the sub board 1. The piece 11 is protruded integrally. The connecting piece 11 is formed in a substantially L shape, and is connected to a connecting portion 11a protruding from one end edge of the insulating substrate 10 in one end direction (downward direction) that is an insertion direction of the sub board 1 into the mother board 2. A protrusion 11b that protrudes from 11a in a direction orthogonal to the protruding direction of the connecting portion 11a (that is, a direction orthogonal to the insertion direction to the mother board 2) is integrally provided. Moreover, the 1st connection pattern 30 is formed in both surfaces of the connection piece 11 (refer FIG.1 (b)). Furthermore, the distance D1 (see FIG. 2B) between the protrusion 11b of the connection piece 11 and one end edge of the insulating substrate 10 is set to be larger than the thickness of the mother substrate 2.

  The mother board 2 is a printed circuit board on which various integrated circuits and other circuit components are mounted. As shown in FIG. 3A, the insulating board 20 of the mother board 2 has a long length that penetrates the front and back. Rectangular connection holes 21 are respectively formed corresponding to the connection pieces 11 of the child board 1. The connection hole 21 is formed to a size that allows the connection piece 11 to be inserted, and the length dimension D2 in the short direction (see FIG. 3B) is particularly equal to the thickness of the child board 1. It has become. Further, as shown in FIG. 3A, the second connection pattern 31 that is soldered to the first connection pattern 30 is provided on the peripheral portion of the connection hole 21 on the back surface side (lower surface side) of the insulating substrate 20. Is formed.

  The child board 1 and the mother board 2 are connected as follows. First, the connection piece 11 of the daughter board 1 is inserted into the connection hole 21 of the mother board 2 from the front surface side (upper surface side) of the mother board 2. Thereafter, the connection piece 11 is moved in the connection hole 21 in a direction orthogonal to the insertion direction of the connection piece 11, thereby positioning the first connection pattern 30 at a predetermined position corresponding to the second connection pattern 31. At the same time, the protrusion 11b of the connection piece 11 is brought into contact with the peripheral edge of the connection hole 21 on the back surface side of the mother board 2 as shown in FIGS. By moving the child substrate 1 in this way, a part of the mother substrate 2 is disposed between one end edge of the insulating substrate 10 of the child substrate 1 and the protrusion 11 b of the connection piece 11. In this state, the first connection pattern 30 and the second connection pattern 31 are soldered on the back surface side of the mother board 2 so that the child board 1 and the mother board 2 are electrically and mechanically connected. Thereby, the connection structure of the printed circuit board of the present embodiment is obtained.

  According to the printed circuit board connection structure of the present embodiment obtained as described above, as shown in FIG. 1B, the protrusion 11 b of the connection piece 11 is a peripheral portion of the connection hole 21 on the back surface side of the mother board 2. Therefore, the child board 1 and the mother board 2 are connected by soldering and locked together. That is, the child board 1 and the mother board 2 are each provided with a latched part made up of the protrusion 11 b of the connection piece 11 and a latching part made up of the peripheral edge of the connection hole 21 on the back surface side of the mother board 2. They are locked together by means.

  Therefore, the force in the pulling direction opposite to the insertion direction (downward direction in FIG. 1 (a)) (upward direction in FIG. 1 (a)) of the child board 1, that is, the direction in which both the boards 1 and 2 are pulled apart. When a force is applied, a part of the force is received by the locking means, and the soldered portions of the connection patterns 30 and 31 (in other words, the solder connecting the connection patterns 30 and 31). Therefore, it is possible to reduce the stress applied to the soldering portion, thereby reducing the stress applied to the soldering site and suppressing the occurrence of problems such as solder peeling.

  Further, as shown in FIG. 4, the two substrates 1 and 2 connected in this way are accommodated in a box-like case 5 whose upper surface is opened, and the case 5 is filled with, for example, an insulating resin 6. Alternatively, by covering both the substrates 1 and 2 with the resin in this manner, the insulation, heat dissipation, and waterproofness of both the substrates 1 and 2 can be improved. In addition, as this resin 6, what is suitable according to a condition can be used.

  By the way, in this embodiment, in order to comply with the European RoHS Directive (Restriction of the use of certain hazardous substances in electrical and electronic equipment directive) and lead-free products such as the Japanese Home Appliance Recycling Law, Lead-free solder that does not contain lead (lead-free solder) is used, thereby providing a printed circuit board connection structure that complies with the RoHS Directive and the Home Appliance Recycling Law.

  Examples of the lead-free solder as described above include SnAgCu, SnCu, SnBi, and SnZn. Here, the SnAgCu system is excellent in heat fatigue resistance and creep characteristics, and the SnZn system has the merit that the melting temperature is close to that of the SnPb system (that is, leaded solder) that has been conventionally used. It is expensive. On the other hand, the SnCu system and SnBi system are low in cost, but the SnCu system has a problem in creep characteristics and the SnBi system has a problem in brittleness.

  However, according to the printed circuit board connection structure of the present embodiment, the stress applied to the soldering portion can be reduced, so that it can be used without any problem even if it is SnCu-based or SnBi-based. Can be achieved. The same applies to the following second to sixth embodiments.

(Embodiment 2)
In addition to the first and second connection patterns, the printed circuit board connection structure of this embodiment is merely mechanically connected by soldering, that is, it is electrically connected to other electronic components and integrated circuits. It is characterized in that a dummy connection pattern (hereinafter referred to as a dummy pattern) that does not have a general connection is provided. In addition, about the structure similar to the said Embodiment 1, the same code | symbol is attached | subjected and description is abbreviate | omitted.

  That is, in the present embodiment, as shown in FIG. 6A, in addition to the first connection pattern 30, the first dummy pattern 30 a is formed on the connection piece 11 of the daughter board 1. Furthermore, as shown in FIG. 6B, in addition to the second connection pattern 31, the peripheral edge of the connection hole 21 corresponds to the first dummy pattern 30 a of the daughter board 1 on the back surface side of the mother board 2. A second dummy pattern 31a is formed.

  In this embodiment, the sub board 1 and the mother board 2 are connected as follows. First, the connection piece 11 of the daughter board 1 is inserted into the connection hole 21 of the mother board 2 from the front surface side (upper surface side) of the mother board 2. Thereafter, the connection piece 11 is moved in the connection hole 21 in a direction perpendicular to the insertion direction of the connection piece 11, whereby the first connection pattern 30 and the dummy pattern 30 a are changed to the second connection pattern 31 and the dummy pattern. The projection 11b of the connection piece 11 is placed at a predetermined position corresponding to each of 31a, and the peripheral portion of the connection hole 21 on the back side of the mother board 2 as shown in FIGS. 5 (a) and 5 (b). Make contact. By moving in this way, a part of the mother board 2 is arranged between one end edge of the insulating substrate 10 of the child board 1 and the protrusion 11b of the connection piece 11. In this state, the first connection pattern 30 and the dummy pattern 30a, and the second connection pattern 31 and the dummy pattern 31a are soldered to the back surface side of the mother board 2, respectively. Are electrically and mechanically connected, whereby the printed circuit board connection structure of this embodiment is obtained.

  According to the printed circuit board connection structure of the present embodiment obtained as described above, since the dummy patterns 30a and 31a are provided in addition to the configuration of the first embodiment, the solder between the daughter board 1 and the mother board 2 is provided. The total area of the attachment portion is increased as compared with the case of the first embodiment. Therefore, the force applied to the soldering site is dispersed, and thereby the stress applied to the soldering site can be reduced as compared with the first embodiment.

(Embodiment 3)
In the first embodiment, as described above, the distance D1 (see FIG. 2B) between the protruding portion 11b of the connection piece 11 and one end edge of the insulating substrate 10 is determined based on the thickness of the mother substrate 2. It is set to be larger. As a result, as shown in FIG. 1B, when the child board 1 and the mother board 2 are connected, the protrusions 11b of the connection piece 11 and the insulating board 10 are caused by the expansion and contraction of both the boards 1 and 2. Thus, an excessive force is not applied between the one edge and the soldered portion of the child board 1 and the mother board 2 so as not to have an adverse effect.

  However, when the distance D1 between the protrusion 11b of the connection piece 11 and the one end edge of the insulating substrate 10 is made larger than the thickness of the mother substrate 2 in this way, either the front surface or the back surface of the mother substrate 2 is used. Therefore, only one stress in the forward direction or the reverse direction with respect to the insertion direction of the sub board 1 can be reduced.

  Therefore, in the present embodiment, as the materials for the insulating substrates 10 and 20 of the sub-substrate 1 and the mother substrate 2, materials that have little expansion / contraction, that is, materials that have a low coefficient of linear expansion are used. For example, a glass cloth / glass nonwoven fabric epoxy resin copper clad laminate (NEMA symbol, CEM-3), which is a composite copper clad laminate, and a glass fabric base epoxy resin copper clad laminate (NEMA symbol, FR) having a low linear expansion coefficient. -4) etc. are used. Further, as a material having a lower linear expansion coefficient, there is a ceramic substrate or the like.

  By using the one having a low linear expansion coefficient in this way, it is possible to reduce to the extent that it is not necessary to consider the influence due to expansion / contraction, and as a result, the protrusion 11b of the connection piece 11 and one end of the insulating substrate 10 The distance D <b> 1 between the edges can be about the thickness of the mother board 2.

  That is, according to the printed circuit board connection structure of the present embodiment, the distance D1 is about the thickness of the mother board 2, the protrusion 11b is on the back surface of the mother board 2, and one end edge of the insulating board 10 is on the mother board 2. Since the respective surfaces can be brought into contact with each other, it is possible to reduce both the forward and reverse stresses with respect to the insertion direction of the daughter board 2.

(Embodiment 4)
As shown in FIGS. 7A and 7B, the printed circuit board connection structure of the present embodiment includes a connection board 71 having a connection piece 71 on which a first connection pattern 90 is formed. A connection structure for connecting to a mother board 8 having a connection hole 81 to be inserted and having a second connection pattern 91 soldered to the first connection pattern 90 at the peripheral edge of the connection hole 81. Are projected on the inner surface of the connection hole 81, and the connection piece 71 is moved in the connection hole 81 in a direction intersecting the insertion direction of the connection piece 71 to move the first connection pattern 90 to the second position. When the connection pattern 91 is positioned at a predetermined position, the connection piece 71 is provided with holes 72 into which the plurality of projections 82 are inserted.

  The sub board 7 is a printed circuit board constituting, for example, a hybrid integrated circuit (HIC). As shown in FIG. 8A, the sub board 7 has a pair of long ends on one end edge (lower end edge) of the insulating board 70. A connecting piece 71 having a rectangular shape is integrally projected with its short direction as a protruding direction from the insulating substrate 70. The connection piece 71 is formed with a plurality of (three in the present embodiment) rectangular hole portions 72 penetrating the front and back in the longitudinal direction, and the peripheral edge portion of each hole 72 on one surface side of the connection piece 71. In addition, a first connection pattern 90 is formed. Here, the hole 72 is formed in such a size that a gap is generated between the hole portion 72 and the protrusion portion 82 when the protrusion portion 82 is inserted.

  The mother board 8 is a printed circuit board on which various integrated circuits and other circuit components are mounted. As shown in FIG. 8B, the insulating board 80 of the mother board 8 has a long length penetrating the front and back. Rectangular connection holes 81 are formed corresponding to the connection pieces 71 of the child substrate 7 respectively. The connection hole 81 is formed so that the length dimension in the longitudinal direction is substantially the same as the length dimension in the longitudinal direction of the connection piece 11, and the length dimension in the lateral direction is at least 2 of the thickness of the sub-board 1. It is formed to be more than double. In addition, the connection hole 81 has a plurality of (three in the present embodiment) protrusions 82 on the inner surface on one end side in the short-side direction, and corresponds to the hole 72 of the daughter board 7 in the longitudinal direction of the connection hole 81. The hole shape is a so-called comb-tooth shape. The projecting dimension of the projecting portion 82 is set to about the thickness of the sub-board 7, so that the front end portion of each projecting portion 82 and the inner side surface on the other end side in the short side direction of the connection hole 81. A space 83 for inserting the connection piece 71 through the connection hole 81 is secured in between. Then, the first connection pattern 90 is soldered to the peripheral edge (that is, the side on which the protrusion 82 protrudes) of the connection hole 81 on the back surface side of the insulating substrate 80. Two connection patterns 91 are formed.

  The child board 7 and the mother board 8 are connected as follows. First, the connection piece 71 of the daughter board 7 is inserted into the space 83 of the connection hole 81 of the mother board 8 from the front surface side (upper surface side) of the mother board 8. Thereafter, the connection piece 71 is moved in the connection hole 81 in a direction orthogonal to the insertion direction of the connection piece 71 (in this embodiment, toward one end in the short direction of the connection hole 81). Then, as shown in FIGS. 7A and 7B, the first connection pattern 90 is positioned at a predetermined position corresponding to the second connection pattern 91, and each protrusion 82 is placed in each hole 72. The rear surface of the protrusion 82 is brought into contact with the inner surface of the hole 72 by being inserted. In this state, by soldering the first connection pattern 90 and the second connection pattern 91 on the back side of the mother board 8, the child board 7 and the mother board 8 are electrically and mechanically connected, Thereby, the connection structure of the printed circuit board of this embodiment is obtained.

  According to the printed circuit board connection structure of the present embodiment obtained as described above, as shown in FIGS. 7A and 7B, the back surface side of the protrusion 82 of the connection hole 81 is the hole 72 of the connection piece 71. Therefore, the child board 7 and the mother board 8 are connected to each other by soldering and locked to each other. That is, the child board 7 and the mother board 8 are provided by a locking means including a locked portion formed by the protruding portion 82 of the connection hole 81 and a locking portion formed by the peripheral edge portion of the hole 72 of the connection piece 71. They are locked together.

  Accordingly, the force in the pulling direction in the direction opposite to the insertion direction (downward direction in FIG. 7A) (upward direction in FIG. 7A) of the child board 7, that is, the direction in which both the boards 7 and 8 are pulled apart. When a force is applied, a part of the force is received by the locking means, and the soldering portions of the connection patterns 90 and 91 (in other words, the solder connecting the connection patterns 90 and 91). Therefore, it is possible to reduce the stress applied to the soldering portion, thereby reducing the stress applied to the soldering site and suppressing the occurrence of problems such as solder peeling. In addition, in the present embodiment, since the child board 7 and the mother board 8 are locked with each other in a state in which the protrusion 82 is inserted into the hole 72, as in the first to third embodiments, the mother board is simply Compared to the case where only the protrusions are brought into contact with the back surface, the sub board 7 and the mother board 8 can be firmly locked, so that a further stress reduction effect can be obtained.

(Embodiment 5)
The printed circuit board connection structure of the present embodiment is similar to the dummy substrate described in the second embodiment as shown in FIGS. 9A to 9C. It is characterized by providing a pattern. In addition, about the structure similar to the said Embodiment 4, the same code | symbol is attached | subjected and description is abbreviate | omitted.

  In other words, in the present embodiment, as shown in FIG. 10A, the first connection pattern 90 is formed on the peripheral edge of the hole 72 on one surface side of the connection piece 71 of the daughter board 7, and FIG. As shown in b), a first dummy pattern 90 a is formed on the peripheral edge of the hole 72 on the other surface side of the connection piece 71. Further, as shown in FIG. 10C, the second connection pattern 91 is formed on the peripheral edge of the connection hole 81 at one end side in the short side direction on the back surface side of the mother board 8, and the tip portions of the respective protrusions 82 are formed. A second dummy pattern 91a corresponding to the first dummy pattern 90a of the daughter board 7 is formed. Here, since the second dummy pattern 91a is soldered to the first dummy pattern 90a formed on the other surface side of the daughter board 7, in the present embodiment, the protrusion 82 of the mother board 8 is formed. As shown in FIG. 9C, the projecting dimension is set to such a size that the tip portion projects to the other surface side of the daughter board 7. Of course, the connecting piece 71 is inserted through the connecting hole 81 between the front end of each protrusion 82 and the inner surface of the connecting hole 81 at the other end in the short direction. A space 83 is secured.

  In this embodiment, the sub board 7 and the mother board 8 are connected as follows. First, the connection piece 71 of the daughter board 7 is inserted into the space 83 of the connection hole 81 of the mother board 8 from the front surface side (upper surface side) of the mother board 8. Thereafter, the connection piece 71 is moved in the connection hole 81 in a direction orthogonal to the insertion direction of the connection piece 71 (in this embodiment, toward one end in the short direction of the connection hole 81). Then, as shown in FIGS. 9A to 9C, the first connection pattern 90 and the dummy pattern 90a are positioned at predetermined positions corresponding to the second connection pattern 91 and the dummy pattern 91a, respectively. The portion 82 is inserted into each hole 72, and the back surface side of the protrusion 82 is brought into contact with the inner surface of the hole 72. In this state, the first connection pattern 90 and the dummy pattern 90a and the second connection pattern 91 and the dummy pattern 91a are soldered on the back surface side of the mother board 8, respectively. Electrically and mechanically connected, whereby the printed circuit board connection structure of this embodiment is obtained.

  According to the printed circuit board connection structure of the present embodiment obtained as described above, since the dummy patterns 90a and 91a are provided in addition to the configuration of the fourth embodiment, the solder between the sub board 7 and the mother board 8 is provided. The total area of the attachment portion is increased as compared with the case of the fourth embodiment. Therefore, the force applied to the soldering site is dispersed, and as a result, the stress applied to the soldering site can be reduced as compared with the fourth embodiment.

(Embodiment 6)
By the way, in the said Embodiment 4, as above-mentioned, when the projection part 82 is penetrated, the hole part 72 is formed in the magnitude | size which is a grade which a clearance gap produces between the projection parts 82. As shown in FIG. As a result, as shown in FIG. 9, when the sub board 7 and the mother board 8 are connected, the expansion and contraction of both the boards 7 and 8 cause a gap between the peripheral edge of the hole 72 and the protrusion 82. An unreasonable force is not applied so that the soldered portions of the child board 7 and the mother board 8 are not adversely affected.

  However, when the hole 72 is formed in such a size that a gap is generated between the protrusion 72 and the hole 72, the hole 72 and the protrusion 82 are either on the front surface side or the back surface side of the mother substrate 8. Therefore, only one of the stresses in the forward direction or the reverse direction with respect to the insertion direction of the sub board 7 can be reduced.

  Therefore, in the present embodiment, as in the third embodiment, as the materials for the insulating substrates 70 and 80 of the child substrate 7 and the mother substrate 8, materials that are less expanded and contracted are used. By using a material having a low linear expansion coefficient in this way, it is possible to reduce it to such an extent that it is not necessary to consider the influence of expansion / contraction, and as a result, there is a gap between the hole 72 and the protrusion 82. It becomes possible to make the size almost impossible.

  That is, according to the printed circuit board connection structure of the present embodiment, when the protrusion 82 is inserted through the hole 72, the hole 72 and the protrusion 82 are connected to both the front surface side and the back surface side of the mother board 8. Thus, it is possible to reduce both the forward and reverse stresses relative to the insertion direction of the sub board 7.

(A) is a schematic side view of the principal part of the connection structure of the printed circuit board of Embodiment 1 of this invention, (b) is a schematic back view same as the above. (A) is a schematic side view of a child substrate same as the above, and (b) is a schematic enlarged view of a portion indicated by A in FIG. (A) is a schematic back view of a mother board same as the above, and (b) is a schematic enlarged view of a portion indicated by B in FIG. It is a schematic sectional drawing of the connection structure of a printed circuit board same as the above. (A) is a schematic side view of the principal part of the connection structure of the printed circuit board of Embodiment 2 of this invention, (b) is a schematic back view same as the above. (A) is a schematic side view of a child board same as the above, (b) is a schematic back view of the mother board same as the above. (A) is a schematic side view of the principal part of the connection structure of the printed circuit board of Embodiment 4 of this invention, (b) is a schematic back view same as the above. (A) is a schematic side view of a child board same as the above, (b) is a schematic back view of the mother board same as the above. (A) is one schematic side view of the principal part of the connection structure of the printed circuit board of Embodiment 5 of this invention, (b) is the other schematic side view same as the above, (c), It is a schematic back view same as the above. (A) is one schematic side view of the same child substrate, (b) is the other schematic side view of the child substrate, and (c) is a schematic back view of the mother substrate. is there. (A) is a schematic front view of the principal part of the connection structure of the conventional printed circuit board, (b) is a schematic side view of the principal part same as the above, (c) is a printed circuit board same as the above. It is a schematic sectional drawing of a connection structure. (A) is a schematic perspective view of the principal part of the other conventional connection structure of a printed circuit board, (b) is a schematic sectional drawing of the connection structure of a printed circuit board same as the above.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Sub board | substrate 11 Connection piece 11b Protrusion part 2 Mother board 21 Connection hole 30 1st connection pattern 31 2nd connection pattern

Claims (6)

  A first printed circuit board having a connection piece on which the first connection pattern is formed; a connection hole through which the connection piece is inserted; and soldered to the first connection pattern at the periphery of the connection hole The second printed circuit board on which the connection pattern 2 is formed, the locking portion provided on either the connection piece side or the connection hole side, and the connection piece provided on the other side of the connection piece within the connection hole. And a locking means including a locked portion that is locked to the locking portion when the first connection pattern is moved to a direction intersecting the insertion direction and positioned at a predetermined position with respect to the second connection pattern. A printed circuit board connection structure characterized by being made.   The locked portion is composed of a protruding portion provided on the connection piece so as to protrude in a direction orthogonal to the insertion direction of the first printed circuit board, and the locking portion is a connection with which the protruding portion abuts. The printed circuit board connection structure according to claim 1, comprising a peripheral edge portion of the hole.   The to-be-latched part is composed of a plurality of projecting parts projecting from the inner surface of the connection hole, and the retaining part is formed of a hole part formed in the connecting piece and into which the plurality of projecting parts are respectively inserted. The printed circuit board connection structure according to claim 1.   A first dummy connection pattern is provided on the connection piece of the first printed circuit board, and the second dummy connection pattern is soldered to the peripheral portion of the connection hole of the second printed circuit board. 4. The printed circuit board connection structure according to claim 1, wherein a dummy connection pattern is provided.   5. The printed circuit board connection structure according to claim 1, wherein the solder used for soldering is a lead-free solder which does not contain lead as a component.   6. The printed circuit board connection structure according to claim 1, wherein the two printed circuit boards are housed in a case, and the case is filled with a resin.

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