JP5510190B2 - Flat cable connection structure - Google Patents

Description

The present invention relates to a connecting structure of a flat cable used for connection between a plurality of printed circuit boards.

  A wire harness and a connector are used for connection between a plurality of substrates in an in-vehicle inverter. In recent years, in-vehicle devices are required to be highly reliable, low cost, small and light, and reduction in substrate size is indispensable for miniaturization.

  In the connection using the connector, since the mounting area to the printed circuit board is widened, it may be difficult to reduce the board size. In connection using a wire harness, since a plurality of wire harnesses are connected manually, it is difficult to reduce the number of man-hours. Therefore, wire harness-less and connector-less connection technologies have been demanded.

  In order to solve the problem, a connection structure has been devised in which flat cables are arranged and electrically connected between a plurality of printed boards. For example, in Patent Document 1, as shown in FIG. 6, in order to provide a collective substrate 23 in which at least two printed circuit board portions 20 and 21 are integrated by a discard plate portion 22, a flexible cable 24 is provided. The two slits 25 are formed at a predetermined interval, and the intermediate portion of the flexible cable 24 is disposed along the back side of the discard plate portion 22 through the two slits 25, and then the flexible cable 24. A cable connection method between the printed circuit board parts 20 and 21 is devised in which both the connection terminals 26 are connected to the electrode pads 27 of the printed circuit board parts 20 and 21 and the discard board part 22 is cut off.

  In Patent Document 1, when the plurality of printed circuit board portions 20 and 21 are connected to each other with the flexible cable 24, the connection terminals 26 of the flexible cable 24 can be easily aligned with the electrode pads 27 on the printed circuit board portions 20 and 21. It is said that.

  In Patent Document 2, as shown in FIG. 7, the covering portion 32 on the distal end side of the terminal portion 31 of the flexible flat cable 30 is left, and the square hole 34 formed in the vicinity of the land 35 of the printed circuit board 33 to be connected is used. It has been proposed to align the terminal portion 31 of the flexible flat cable 30 and the land 35 of the printed circuit board 33 by inserting the remaining covering portion 32.

JP-A-8-162757 JP 2005-252016 A

  In the connection structure disclosed in Patent Document 1, when the flexible cable 24 is aligned, the flexible cable 24 is provided on the collective substrate 23 formed by integrating the printed circuit board portions 20 and 21 and the discard plate portion 22. The step of passing through the two slits 25 is essential. At this time, since the flexible cable 24 is positioned in a state of being bent through the slit 25, the flexible cable 24 is bent in the vicinity of the connection terminal 26, and the electrode pads 27 of the printed circuit board portions 20 and 21 are thus bent. The connection terminal 26 is in a floating state. Particularly, since it is necessary to consider the length of the flexible cable 24 connected to the collective substrate 23 by an amount corresponding to the thickness of the collective substrate 23 and the width of the slit 25, the flexible cable 24 is not optimal in length. There is a possibility that the bending of the cable 24 becomes remarkable. When the flexible cable 24 is curved, there is a problem that when the connection terminal 26 and the electrode pad 27 are connected by solder or the like, the connection is difficult and the connection is insufficient.

  Further, in the connection structure shown in Patent Document 2, the flexible flat cable 30 is inclined with respect to the printed circuit board 33 in order to insert the covering portion 32 into the square hole 34 positioned in the longitudinal direction, and the terminal portion 31 and the land There is a possibility that a gap may be generated between In particular, when the flexible flat cable 30 is bent due to the curl in the winding process when the flexible flat cable 30 is formed and the curve remains, the initial bending of the flexible flat cable 30 is performed in this structure. Can not be suppressed. Therefore, the terminal part 31 floats with respect to the land 35 of the printed circuit board 33, and when connecting the terminal part 31 and the land 35 similarly to patent document 1, it is difficult to connect and the connection becomes insufficient. There is.

  Further, in order to easily connect a plurality of printed boards together with a flat cable, reflow soldering is desirable, and there is a strong demand for providing a structure that suppresses the bending of the flat cable.

Therefore, the object of the present invention is to solve the problems of the prior art, facilitate the alignment of the connection terminal to the electrode on the printed circuit board, and near the connection terminal of the flat cable connected between the plurality of printed circuit boards. it is possible to reduce poor connection due to deformation is to provide a connecting structure of a flat cable.

In order to solve the above-described problems, the present invention includes at least two printed circuit board portions having a plurality of electrode pads, and includes the printed circuit board portions of the collective substrate having a discard plate portion that connects and integrates the printed circuit board portions. , a connecting structure of a flat cable connecting via a flat cable, the flat cable, the conductors disposed in parallel a plurality in the width direction, the plurality of conductors made of film-like covering material having an insulating property And a bent portion formed by bending the covering material on both sides in the width direction of the covering portion so as to protrude downward from a position where the conductor covers the conductor. has, on the assembly substrate is a flat cable fixing slits for inserting the folded portion formed on both sides in the width direction of the flat cable The bent portion is inserted into the flat cable fixing slit so that the flat cable is fixed to the collective substrate, and the connection terminals of the conductors are respectively disposed on the corresponding electrode pads. Is.

The front Symbol aggregate substrate, ablation slit for ablating the discarded plate portion from the assembled board may be formed intermittently.

Before SL and the extending direction of the cut slit and extending direction of the flat cable fixing slits are orthogonal, and said resection slit may be made of a plurality of slits pieces formed in series.

  ADVANTAGE OF THE INVENTION According to this invention, alignment of the connection terminal to the electrode on a printed circuit board can be made easy, and the connection failure accompanying the deformation | transformation of the connection terminal vicinity of the flat cable connected between several printed circuit boards can be reduced. .

FIG. 1 is a perspective view of a flat cable obtained by bending a covering material. FIG. 2 is a plan view of the collective board on which flat cable fixing slits are formed. FIG. 2 (a) shows the collective board before flat cable fixation, and FIG. 2 (b) shows the collective board after flat cable fixation. . 3 is a cross-sectional view taken along the line AA of FIG. 2B, FIG. 3A shows the collective substrate before the flat cable is fixed, and FIG. 3B shows the collective substrate after the flat cable is fixed. 3 (c) shows a state in which the discarded plate portion is cut out from the collective substrate in FIG. 3 (b), and FIG. 3 (d) shows a state in which a notch is provided in the bent portion of the flat cable in FIG. 3 (c). Show. 4B is a cross-sectional view taken along the line BB of FIG. 2B. FIG. 4A shows the collective substrate before the flat cable is fixed, and FIG. 4B shows the collective substrate after the flat cable is fixed. FIG. 5 is a perspective explanatory view of a flat cable according to another embodiment in which a notch is formed in a bent portion. FIG. 6 is an explanatory diagram showing the characteristics of the conventional example (Patent Document 1). FIG. 7 is an explanatory diagram showing the characteristics of the conventional example (Patent Document 2).

  Hereinafter, the configuration of the embodiment of the present invention will be described in detail with reference to FIGS.

Here, FIG. 1 is a perspective view of a flat cable subjected to bending to be covered material, FIG. 2 (a) is a plan view of a collective substrate formed with the flat cable fixing slits, and FIG. 2 (b) FIG. 2 is a plan view of a collective substrate to which the flat cable of FIG. 3 (a), 3 (b), 4 (a), and 4 (b) are cross-sectional views taken along lines AA and BB shown in FIG. 2 (b), respectively. Is a cross section before fixing the flat cable, and (b) is a cross section after fixing.

  First, as shown in FIG. 1, the flat cable 1 includes a conductor 13 formed in a linear shape and arranged in parallel in the width direction (horizontal direction), and a covering that covers (laminates) the plurality of conductors 13 from above and below. Part 14.

  The conductor 13 is made of a rectangular wire plated with Sn, and has connection terminals 2 at both ends. Each of the connection terminals 2 is exposed from the covering portion 14 and is formed side by side in the width direction.

  The covering portion 14 is formed of a thin film-like covering material having insulating properties. The covering material is made of a thin resin film excellent in heat resistance and insulation, for example, polyimide. The covering portion 14 is formed wider than the conductor group 15 composed of the plurality of conductors 13 described above, and covers the conductor group 15 at the center in the width direction. The covering portion 14 has bent portions 3 formed by bending a covering material so as to protrude downward from a position where the conductor group 15 of the covering portion 14 is covered on both sides in the width direction. For example, as shown in FIG. 1, the bent portion 3 is formed by being bent at a right angle along a fold line 16 (longitudinal direction of the conductor 13) parallel to the conductor 13. The bent portion 3 is for insertion into the flat cable fixing slit 10 of the collective substrate 4 when the conductor 13 is connected to the collective substrate 4 which is the printed circuit board shown in FIG. By inserting the bent portion 3 into the flat cable fixing slit 10, the flat cable 1 is fixed to the collective substrate 4 and the connection terminal 2 of the conductor 13 is automatically positioned on the electrode pad 7 of the collective substrate 4. It has become so.

  The flat cable in the course of production in which the conductor group 15 is covered with the covering material is flat, but the both sides shown in FIG. 1 are heated and pressed so that both side portions in the width direction of the covering portion 14 are bent downward. Such a bent portion 3 is formed. Note that the length (L) of the bent portion 3 inserted into the flat cable fixing slit 10 is half (D / 2) of the thickness (D) of the aggregate substrate 4 or half (D / 2). ) From the viewpoint of fixing the flat cable 1 and preventing misalignment.

  Next, as shown in FIG. 2A, the collective substrate 4 includes two printed circuit board portions 5 and 6 that are formed apart from each other, and the printed circuit board portion 5 that is formed between the printed circuit board portions 5 and 6. And a discarding plate portion 8 that connects and integrates 6.

  The printed circuit board portions 5 and 6 are connected via the flat cable 1. A plurality of electrode pads 7 for connecting the connection terminals 2 of the flat cable 1 are formed on the upper surfaces of the printed circuit board portions 5 and 6. The electrode pads 7 are formed in a row on the substantially outer peripheral portion of the printed circuit board portions 5 and 6 facing the discard plate portion 8. The same number of electrode pads 7 as the connection terminals 2 are formed so as to correspond one-to-one with the connection terminals 2 on one end side of the flat cable 1.

  Further, a flat cable fixing slit 10 into which the bent portion 3 of the flat cable 1 can be inserted is formed in the printed circuit board portions 5 and 6 facing the discard plate portion 8 and the discard plate portion 8. The flat cable fixing slit 10 is used for positioning the flat cable 1 when the connection terminal 2 of the flat cable 1 is connected to the electrode pad 7, and the bent portion 3 is inserted into the flat cable fixing slit 10. The flat cable 1 is fixed to the collective substrate 4 and the connection terminals 2 of the conductors 13 are automatically arranged on the corresponding electrode pads 7 respectively. Further, two flat cable fixing slits 10 are formed at a predetermined interval. Here, the predetermined interval is the same as the interval between the bent portions 3 of the covering portion 14 and is at least equal to or smaller than the width dimension of the flexible cable 1 and one end of the row of electrode pads 7 arranged on the printed circuit board portions 5 and 6. It is more than the dimension from the other end. The length of the flat cable fixing slit 10 is slightly longer than the length of the covering portion 14 of the flat cable 1. Further, the width of the flat cable fixing slit 10 is formed to be about twice the thickness of the covering portion 14 so that the bent portion 3 of the flat cable 1 can be accommodated. As shown in FIG. 2 (b), the length of the discard plate portion 8, the flat cable fixing slit 10 and the covering portion 14 of the flat cable 1 is stored in the flat cable fixing slit 10. In this case, the connection terminals 2 at both ends of the flat cable 1 and the electrode pads 7 of the printed circuit board portions 5 and 6 are set in advance to have a predetermined length so that they can be automatically aligned.

  In the collective substrate 4 between the discard plate portion 8 and the printed circuit board portions 5 and 6, a cutting slit 9 for making the discard plate portion 8 excisable from the collective substrate 4 is formed. The excision slit 9 is composed of a plurality of slit pieces 17a and 17b formed intermittently in series along the width direction of the printed circuit board portions 5 and 6 (parallel direction of the electrode pads 7). And a plurality of slit pieces 17a, 17b are formed so that the extending directions thereof are orthogonal to each other. In particular, each slit piece 17a, 17b is formed away from the flat cable fixing slit 10 so as not to cross the flat cable fixing slit 10, and is formed by the flat cable fixing slit 10 and the slit pieces 17a, 17b. The shape of the slit plate 8 is maintained by maintaining the surrounded discard plate portion 8.

  Next, a method for connecting the printed circuit board portions 5 and 6 and the flat cable 1 will be described.

  First, a certain amount of cream solder is applied to the electrode pads 7 of the collective substrate 4 shown in FIG. 2 using a metal mask.

  Next, the bent portion 3 of the flat cable 1 shown in FIG. 1 is manually housed in the flat cable fixing slit 10 as shown in FIGS. 2 (b), 3 and 4. At this time, since the flat cable fixing slit 10 does not intersect with the cutting slit 9 and is formed in a simple linear shape, the bent portion 3 can be smoothly accommodated (inserted) in the flat cable fixing slit 10. .

  Accordingly, the connection terminals 2 and the respective printed circuit board portions 5 at both ends of the flat cable 1 are obtained from the relationship between the length of the discard plate portion 8, the shape of the flat cable fixing slit 10, and the shape of the bent portion 3 of the flat cable 1. , 6 can be easily aligned and fixed with the electrode pad 7. That is, by inserting the bent portion 3 into the flat cable fixing slit 10, the flat cable 1 is fixed to the collective substrate 4, and the connection terminals 2 of the conductors 13 are disposed on the corresponding electrode pads 7, respectively. The connection terminal 2 can be easily and accurately positioned on the electrode pads 7 of the fifth and sixth electrodes.

  Next, solder connection is performed by putting the collective substrate 4 and the flat cable 1 aligned and fixed on the collective substrate 4 into a reflow furnace (not shown). Since the bent portion 3 is formed in the flat cable 1, initial deformation such as the flat cable 1 being curved in the longitudinal direction is suppressed, so that connection failure due to deformation in the vicinity of the connection terminal 2 of the flat cable 1 is prevented. Can be reduced. In addition, when the bent portion 3 is inserted into the flat cable fixing slit 10, the flat cable 1 is automatically aligned and fixed, and the reflow solder connection is not displaced due to vibration or the like. A connection state can be obtained. Moreover, since the cream solder applied to the electrode pads 7 is melted and separated into each electrode pad 7 by the surface tension, no short circuit occurs.

  As described above, the two printed circuit board portions 5 and 6 can be easily connected by the flat cable 1 in which the covering portion 14 is bent. Further, after connecting the printed circuit board portions 5 and 6 by the flat cable 1, as shown in FIG. 3C, the collective substrate 4 is cut with a cutting machine or the like in accordance with the cutting slit 9, and the discard plate portion 8 is removed. Resect. Since the cutting slit 9 includes a plurality of slit pieces 17a and 17b formed in series, the discard plate portion 8 can be easily cut only by cutting the collective substrate 4 between the slit pieces 17a and 17b. The cutting machine may be a simple hand tool that cuts the aggregate substrate between two blades. Furthermore, the inter-board connection component 18 formed by connecting the printed circuit board portions 5 and 6 with the flat cable 1 is often assembled to other components such as an in-vehicle device by bending the flat cable 1. For this reason, as shown in FIG.3 (d), the center part of the conductor longitudinal direction of the bending part 3 is excised from the flat cable 1, and the board | substrate connection process is complete | finished.

  In this way, on both sides of the covering portion 14 in the width direction, the covering portion 14 has the bent portions 3 formed by being bent so as to protrude downward from the position where the conductor 13 is covered. The rigidity of the flat cable 1 itself can be increased, and the initial deformation of the flat cable 1 can be corrected. Then, by inserting the bent portion 3 of the flat cable 1 into the flat cable fixing slit 10, the positioning of the connection terminal 2 to the electrode pad 7 on the printed circuit board portions 5, 6 can be facilitated, and a plurality of printed circuit boards The connection failure accompanying the deformation | transformation of the connection terminal 2 vicinity of the flat cable 1 connected between the parts 5 and 6 can be reduced.

  In addition, flat cable fixing slits 10 for inserting bent portions 3 formed on both sides of the flat cable 1 in the width direction are formed in the aggregate substrate 4, and the bent portions 3 are inserted into the flat cable fixing slits 10. As a result, the flat cable 1 is fixed to the collective substrate 4 and the connection terminals 2 of the conductors 13 are arranged on the corresponding electrode pads 7, so that the bent portion 3 of the flat cable 1 is used for fixing the flat cable. By accommodating in the slit 10, the position of the flat cable 1 can be fixed at the time of connection, the positioning of the connection terminal 2 to the electrode pad 7 on the printed circuit board parts 5, 6 can be facilitated, and a plurality of printed circuit board parts Connection failure due to deformation in the vicinity of the connection terminal 2 of the flat cable 1 connected between 5 and 6 can be reduced.

  Since the collecting substrate 4 is formed with intermittent slits 9 for cutting the discard plate portion 8 from the collective substrate 4, the discard plate portion 8 can be easily cut.

  Further, the extending direction of the cutting slit 9 and the extending direction of the flat cable fixing slit 10 are orthogonal to each other, and the cutting slit 9 is composed of a plurality of slit pieces 17a and 17b formed in series. The flat cable fixing slit 10 and the excision slit 9 can be prevented from crossing, the length of the collective substrate 4 to be cut can be kept short, and the discarded plate portion 8 can be easily excised.

  In the above-described embodiment, the bent portion 3 of the flat cable 1 has the effect of increasing the rigidity of the flat cable 1, but this effect is obtained by bending the flat cable 1 in the vicinity of the connection terminal 2. As long as it can be corrected, the notch 19 is provided at the center in the longitudinal direction of the bent portion 3 as shown in FIG. May be provided. Specifically, of the pair of bent portions 3 formed on both sides of the covering portion 14, the notched portions 19 may be provided in the bent portions 3 on one side or both sides. With such a structure, it is possible to suppress the flat cable 1 from being bent along the longitudinal direction of the conductor 13, and at the time of cutting away the discard plate portion 8 from the collective substrate 4, the discard plate portion 8. The risk of the flat cable 1 itself being cracked or damaged by the stress applied to removing the cable can be reduced.

  Further, when the cutout portion 19 is formed only in the bent portion 3 on one side of the covering portion 14, the flat cable 1 can be prevented from being bent along the conductor longitudinal direction, and the collective substrate 4 When cutting away the discarding plate part 8, the effect of reducing the risk of the flat cable 1 itself being cracked or damaged by the stress applied to removing the discarding plate part 8 can be obtained more effectively.

  Further, the bent portion 3 may include a reinforcing member (not shown) such as a metal wire. By setting it as the bending part 3 which contains a reinforcement member inside, the rigidity for suppressing the curve of the flat cable 1 in the longitudinal direction can be improved.

DESCRIPTION OF SYMBOLS 1 Flat cable 2 Connection terminal 3 Bending part 4 Collected board 5 Printed circuit board part 6 Printed circuit board part 7 Electrode pad 8 Discarding board part 9 Cutting slit 10 Flat cable fixing slit 13 Conductor 14 Covering part 15 Conductor group 16 Plot line 17a Slit piece 17b Slit piece 18 Inter-board connection component 19 Notch

Claims (3)

The printed circuit board unit having a plurality of electrode pads and having at least two flat cables to the printed circuit board portions of the collective substrate having discarded plate portion integrally connected to these printed circuit board unit, connected via a flat cable The connection structure of
The flat cable includes a plurality of conductors arranged in parallel in the width direction and a covering portion made of an insulating film-like covering material that covers the plurality of conductors, and both sides of the covering portion in the width direction. And having a bent portion formed by bending the covering material so as to protrude downward from a position of the covering portion covering the conductor,
In the aggregate substrate, there are formed flat cable fixing slits for inserting bent portions formed on both sides of the flat cable in the width direction, and the bent portions are inserted into the flat cable fixing slits. The flat cable connection structure, wherein the flat cable is fixed to the collective substrate, and the connection terminals of the conductors are respectively disposed on the corresponding electrode pads. The flat cable connection structure according to claim 1 , wherein slits for excision for excising the discard plate portion from the collective substrate are intermittently formed on the collective substrate. The flat cable according to claim 2, wherein an extending direction of the cutting slit and an extending direction of the flat cable fixing slit are orthogonal to each other, and the cutting slit includes a plurality of slit pieces formed in series. Connection structure.

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