JPH0645370U - Mounting structure of printed wiring board - Google Patents

Abstract

(57) [Summary] (Modified) [Purpose] In a printed wiring board mounting structure in which a metal base wiring board is provided on the printed wiring board so that the main surfaces are substantially orthogonal to each other, the addition to the metal base wiring board is performed. Eliminates the risk of damage to the solder material of the fixing means due to pressure, inclination of the metal base wiring board, dropout of mounted parts on the metal base wiring board, high density mounting structure, large mechanical strength, An object is to obtain a mounting structure of a printed wiring board which is easy to manufacture and has high reliability. [Structure] A metal base wiring board is formed in an L-shape or a U-shape, and the protrusion of the metal base wiring board is inserted into the hole of the printed wiring board. Mainly, they are fixed by soldering, and the melting point of the solder material for fixing the components on the metal base wiring board is higher than the melting point of the solder material for fixing the metal base wiring board. Characterize.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a printed wiring board mounting structure, and more particularly to a printed wiring board mounting structure suitable for high-density mounting in which a metal base wiring board is provided on the printed wiring board so that the main surfaces are substantially orthogonal to each other.

[0002]

[Prior art]

 2. Description of the Related Art In the construction of electronic devices and the like, a mounting structure in which various parts are mounted on a printed wiring board is widely known. As the printed wiring board, a wiring board in which copper foil is formed on both sides or one side (2) of an insulating base such as a glass / epoxy copper clad laminate or a paper / phenol copper clad laminate Is widely used. On the other hand, in the mounting of chip parts, etc., metal-based wiring boards such as aluminum-based copper-clad boards with excellent heat dissipation have also been put into practical use.

In order to realize high-density mounting using these wiring boards, metal-based wiring boards are arranged on the printed wiring board such that their main surfaces are orthogonal to each other, and Electronic equipment is used that has a printed wiring board mounting structure in which parts are mounted.

FIG. 1 is a structural diagram of a conventional example, 1 is a metal base wiring board, 2 is a printed wiring board, 3 is a component such as an electronic component, 4 is a conductor portion such as a copper foil formed in 1, Reference numeral 5 is an insulating layer formed in 1, 6 is a protrusion of 1, and 7 is an insertion hole of the printed wiring board 2 into which the protrusion 6 is inserted.

FIG. 2 is a combined perspective view of the metal base wiring board 1 and the printed wiring board 2 of FIG. 1, and the same reference numerals indicate the same parts. (Similarly in the following, the same symbols represent the same parts.) In addition, in FIG. 2, the parts mounted on the main surfaces of the metal base wiring board 1 and the printed wiring board 2 and the wiring patterns, etc. Is omitted in the illustration.

FIG. 3 is an enlarged side view of FIG. Reference numeral 8 is a metal base such as aluminum of the metal base wiring board 1, 9 is a solder material for fixing the component 3 such as an electronic component to the conductor portion 4 of 1 and 10 is the conductor portion 4 of the protrusion 6 of 1. And a solder material for fixing the conductor portion 11 of the printed wiring board 2 and a resist 12.

As shown in FIGS. 1, 2 and 3, in the conventional structure, the printed wiring board 2 on which predetermined components are mounted, the metal base wiring board 1 and the main surfaces thereof are substantially orthogonal to each other. As shown in FIG. 2, the protrusion 6 provided on one side is inserted into the insertion hole 7 provided at 2, and the conductor portion 4 and the conductor portion 3 are electrically connected between the conductor portion 4 and the conductor portion 11 with the solder material 10. , Mechanically bonded mounting structure was constructed.

In such a conventional structure, the compressive force applied to the solder material 10 as the fulcrum B (FIG. 3) and the pressurization in the Y direction (FIG. 2) do not pose a problem, but in the X direction (FIG. 2). Pressurization of f (FIG. 3) causes stress on the fixed portion of the solder material 10 as a lever force due to the fulcrum A (FIG. 3), and the solder joint is easily damaged.

Further, after the component 3 is fixed to the conductor portion 4 of the metal-based wiring board 1 with a solder material 9 of a normal Sn / Pb eutectic solder system (melting point of about 180 ° C.) in advance, 1 is set in the insertion hole 7 of the printed wiring board 2, and the portion of the solder material 10 is soldered together with the pattern surface in the solder bath.

At this time, in the conventional structure, the Sn / Pb eutectic solder system having a melting point of about 180 ° C. is usually used for the solder material 9 and the solder material 10. Since the metal base wiring board 1 has good heat conduction during the welding step in the solder bath, the solder material 9 is easily remelted and may drop off when the weight of the component 3 is large.

[0011]

[Problems to be solved by the device]

 In a printed wiring board mounting structure in which metal base wiring boards are provided on the printed wiring board so that their main surfaces are substantially orthogonal to each other, in the mounting direction of the surface direction to the metal base wiring board, the fixing means is used. The solder material is easily damaged, the mounting of the metal base wiring board is easy to tilt when the processing accuracy of the metal base wiring board insertion hole of the printed wiring board is rough, and the metal base wiring board The problem is that when soldering to a printed wiring board, the solder material on the metal-based wiring board is remelted and parts are likely to fall off.

(4)

[Means for Solving the Problems]

 According to the present invention, a metal base wiring board is formed in an L-shape or a U-shape, and the protruding portion of the metal base wiring board is inserted into the hole of the printed wiring board, and the protruding portion and the print are formed. The means for fixing the wiring board by soldering, the melting point of the solder material for fixing the components on the metal base wiring board, and the melting point of the solder material for fixing the protrusions of the metal base wiring board and the printed wiring board Means for raising the melting point above the melting point, means for making the solder material for fixing parts on the metal base wiring board a eutectic solder system of Ag / Sn and raising the melting point to about 221 ° C. It is characterized by a means for fixing components on a metal-based wiring board by using fixing together. As a result, it is possible to obtain a mounting structure of a printed wiring board with improved packaging density, high mechanical strength, easy manufacture, and high reliability.

[0013]

【Example】

 FIG. 4 is a perspective structural view showing an embodiment of a metal base wiring board used in the present invention. FIG. 5 is a perspective structural view showing an embodiment of the present invention.

The first essential part of the present invention is to have a structure in which the metal base wiring board 1 is bent into an L-shape or a U-shape. That is, as shown in the plan view of the metal base wiring board of FIG. 6, the metal base wiring board is formed in the L-shape of FIG. 6A and the U-shape of FIG. 6B. The L-shaped and U-shaped expressions are used as terms that are symbolically easy to understand, and do not strictly define the angle, length, etc., but rather the metal base on the main surface of the printed wiring board. The wiring board is installed stably in a bent shape.

Therefore, as compared with the conventional structure, the bent sides reinforce each other in both the X direction and the Y direction to increase the mechanical strength and to increase the metal base wiring board 1 and the printed wiring board. The stress on the solder joint with the plate 2 is reduced. Further, even if the insertion hole 7 is large and loose with respect to the protrusion 6, the metal base wiring board 1 does not incline, so that the setting in the soldering process is reliable and the dimensional accuracy is improved. . (5)

Next, the solder joints of the wiring boards 1 and 2 in the embodiment of the present invention shown in FIG. 5 can be illustrated similarly to the side enlarged view of FIG. In the embodiment of the present invention, the solder material 9 is, for example, an Ag / Sn eutectic solder system having a melting point of about 221 ° C., and the Sn / Pb eutectic solder system of the solder material 10 having a melting point of about 180 ° C. On the other hand, by using the solder material 9 having a high melting point, the remelting of the solder material 9 does not occur even in the soldering process of the solder material 10, and there is no risk of the component 3 falling off.

However, when the weight of the component 3 is large, for example, when a power semiconductor element or a large capacitor is used, the solder material 9 is likely to fall off due to softening or the like. FIG. 7 shows an embodiment of a fixing means of the component 3 for solving the problem. The external electrodes and the like of the component 3 and the conductor portion 4 are fixed by the soldering portion 13, and the adhesive 14 such as resin is used. Bonding was also used to increase mechanical strength. In addition, the number and place of fixation can be arbitrarily selected.

In each drawing of the embodiment of the present invention, parts such as mounting of components and wiring patterns are omitted, but it is obvious that modifications, additions, conversions and the like can be made within the scope of the present invention. Is.

[0019]

[Effect of device]

 As described above, a metal-based wiring board has a large mechanical strength as a printed wiring board, does not cause structural defects due to inclination, does not cause damage to the soldering material for fixing, and further Since a highly reliable and easily manufactured high-density mounting structure that does not cause parts to fall off is obtained, it can be used in a variety of devices, including electronic devices, and has great industrial effects.

[Brief description of drawings]

FIG. 1 is a structural diagram of a conventional example. (6)

FIG. 2 is a combined perspective view of a conventional example.

FIG. 3 is an enlarged side view.

FIG. 4 is a perspective view of a metal base wiring board according to an embodiment of the present invention.

FIG. 5 is a perspective structural view of an embodiment of the present invention.

FIG. 6 is a plan layout view of an embodiment of the present invention, in which (a) is an L-shape and (b) is a U-shape.

FIG. 7 is a structural diagram for fixing parts according to an embodiment of the present invention.

[Explanation of symbols]

 1 Metal Base Wiring Board 2 Printed Wiring Board 3 Parts 4 Conductor 5 Insulating Layer 6 Protrusion 7 Insertion Hole 8 Metal Base 9 Solder Material 10 Solder Material 11 Conductor 12 Resist 13 Solder Part 14 Adhesive

Claims (4)

[Scope of utility model registration request] 1. In a printed wiring board mounting structure in which at least components are fixed to a printed wiring board such that main surfaces thereof are substantially orthogonal to each other, the metal base wiring board is L-shaped or U-shaped. A mounting structure for a printed wiring board, which is formed in a square shape, and the projection of the metal base wiring board is inserted into the hole of the printed wiring board, and the projection and the printed wiring board are fixed by soldering. 2. A melting point of a solder material for fixing a component on a metal base wiring board is set higher than a melting point of a solder material for fixing a protrusion of a metal base wiring board and a printed wiring board. Printed wiring board mounting structure. 3. A solder material for fixing a component on a metal base wiring board is a eutectic solder system of Ag / Sn and has a melting point of about 22.
A printed wiring board mounting structure characterized in that the temperature is 1 ° C. 4. A printed wiring board mounting structure in which components are fixed on a metal base wiring board by using a fixing means using a solder material and a fixing means using an adhesive.