JPH07135384A - Printed board with circuit component and fixing method of circuit component - Google Patents

Abstract

PURPOSE:To facilitate fixing of a heat generating circuit component equipped with a heat plate to a printed board, and to provide a printed board mounting reduced number of circuit components. CONSTITUTION:A power transistor 2 and a heat plate 3 are brought into tight contact by means of a screw 4 thus forming a circuit component assembly A. The assembly A is temporarily fixed to a printed board 1 while inserting the screw 4 partially into a through hole 8 of the printed board 1. The printed board 1 is then dipped into a solder bath thus securing the screw 4 and an extra land 10 through a solder 11.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printed circuit board with a circuit component, and more particularly to a printed circuit board with a heat generating circuit component having a heat radiating plate and a method for mounting the circuit component.

[0002]

2. Description of the Related Art Conventionally, various circuit components are mounted on a printed circuit board 1. Particularly, as shown in FIG. 3, a heat generating circuit component 2 such as a power transistor is disposed together with a heat sink 3 and the printed circuit board 1. It was attached to the printed circuit board 1 by sandwiching it with the screw 4 and the nut 5. This power transistor 2
The lead 6 is inserted into the printed circuit board 1 and is electrically connected to the land 7 connected to a circuit component (not shown) on the back surface thereof via solder.

[0003]

Conventionally, in order to attach the power transistor 2 and the heat radiating plate 3 to the printed circuit board 1, a manual work using a jig or the like has been general, and the work efficiency is poor and the productivity cannot be increased. Furthermore, since many parts are used for mounting, the number of parts is large and the cost is high.

[0004]

In order to solve the above problems, the present invention provides a printed circuit board having a through hole, a heat-generating circuit component mounted on the printed circuit board, and a heat dissipation circuit for dissipating the circuit component. And a circuit component assembly in which the plate and the heat sink plate side are assembled together by screws from the circuit component side, and a part of the screw that has been pulled out to the heat sink plate side is inserted into the through hole, Part of is fixed by soldering, and circuit parts are attached by mounting heat generating circuit parts to be mounted on a printed circuit board and a heat radiating plate for radiating the circuit parts with screws to form a circuit part assembly. Then, a part of the screw is inserted into a through hole provided in the printed board, and the screw and the printed board are fixed by soldering.

[0005]

The assembly of the heat-generating circuit component and the heat sink and its mounting on the printed circuit board can be performed in separate steps to facilitate the work, and the number of components required for mounting can be reduced.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below with reference to FIGS. 1 and 2, but the same or corresponding portions as those in the conventional example will be designated by the same reference numerals and detailed description thereof will be omitted.

Before being mounted on the printed circuit board 1, a power transistor 2 which is a heat-generating circuit component and a heat radiating plate 3 which radiates the heat generated by the power transistor 2 are assembled with screws 4 to form a circuit component assembly. Form A.
The heat sink 3 has taps, and the heat sink 3 and screws 4
The power transistor 2 is sandwiched by the head of the power transistor 2 and the power transistor 2 is closely attached.

Further, through holes 8 and 9 into which a part of the screw 4 and the lead 6 of the power transistor 2 are inserted are formed in the printed circuit board 1, respectively, and a waste land 10 is provided around the through hole 8 corresponding to the screw 4. , Lands 7 are formed around the through holes 9 corresponding to the leads 6, respectively. And screw 4
When the circuit component assembly A assembled by, that is, the power transistor 2 and the heat radiating plate 3 are mounted on the printed circuit board 1, the screw 4 and the lead 6 are inserted into the corresponding through holes 8 and 9 and fixed in position. Then, in this state, the printed circuit board of the circuit component assembly A is obtained by dipping in the solder bath and soldering, and by forming the solder 11 between the screw 4 and the discard land 10 and between the lead 6 and the land 7. 1 and the electrical connection between the lead 6 and the land 7 are completed at the same time.

According to the above-described embodiment, the number of working steps is smaller than that of the conventional one, and the number of parts can be reduced. Furthermore, before mounting the printed circuit board 1, the power transistor 2 and the heat sink 3 must be assembled beforehand. Therefore, the work becomes easy, the work efficiency is good, and the productivity is increased.

As a second embodiment of the present invention, as shown in FIG. 2, the power transistor 2 and the heat sink 3 are assembled with the screw 4, but all the screws 4 have screw threads.
Rather than providing 12, the thread 12 is formed only in a portion necessary for assembling the power transistor 2 and the heat sink 3, and a portion not related to fixing, that is, a portion to be inserted into the through hole 8 of the printed circuit board 1. The thread 12 is not formed on the. With the above configuration, in the process of assembling the power transistor 2 and the heat sink 3, only the part where the power transistor 2 and the heat sink 3 are assembled is required to be rotated and assembled, and the part not related to the assembly, that is, the printed board 1 of the screw 4 is assembled. In the portion to be inserted into the through hole 8, it is not necessary to insert the power transistor 2 and the heat radiating plate 3 through the screw 4 without engaging with the screw 4, and the work efficiency is increased accordingly.

The present invention is not limited to the above embodiment, but can be variously modified within the scope of the gist of the present invention. For example, the diameter of the screw 4 and the size of the through hole 8 may be approximately the same, and the screw 4 may be press-fitted into the through hole 8 to be temporarily fixed, or an adhesive may be used to form the printed circuit board 1
You may temporarily stop at. Further, in the above-described embodiment, the discard land 10 is formed around the through hole 8 through which the screw 4 is inserted. You may keep it.

The present invention has been described by taking the power transistor 2 as an example of a heat-generating circuit component, but any component may be used as long as it is a circuit component 2 that requires the heat dissipation plate 3, such as an IC. But it's okay. Further, the shape of the heat dissipation plate 3 may be freely designed according to the amount of heat generated by the circuit component 2.

[0013]

According to the above-described embodiment, the number of parts required for mounting the circuit component on the printed circuit board can be reduced, and the mounting can be performed from the manual work to the mounting using the machine, so that the number of assembling steps can be reduced. Workability is increased,
Cost can be reduced. Further, by assembling the circuit component and the heat sink in a separate process, the circuit component and the heat sink can be adhered well and heat can be efficiently dissipated.

[Brief description of drawings]

FIG. 1 is a sectional view of a first embodiment of the present invention.

FIG. 2 is an enlarged sectional view of a main part of the second embodiment of the present invention.

FIG. 3 is a sectional view of a conventional example.

[Explanation of symbols]

 1 Printed Circuit Board 2 Power Transistor (Circuit Part) 3 Heat Sink 4 Screw 8 Through Hole 10 Discarded Land 11 Solder 12 Screw Thread A Circuit Part Assembly

Claims (3)

[Claims] 1. A printed circuit board having a through hole, a heat-generating circuit component attached to the printed circuit board, and a heat radiating plate for radiating heat of the circuit component are pierced and assembled from the circuit component side to the heat radiating plate side by screws. Circuit part assembly, wherein a part of the screw protruding toward the heat dissipation plate is inserted into the through hole, and the through hole and part of the screw are fixed by soldering. Printed board. 2. The printed circuit board with a circuit component according to claim 1, wherein a screw thread is provided only in a portion of the screw where the heat-generating circuit component and the heat dissipation plate are assembled. 3. A heat-generating circuit component to be mounted on a printed circuit board and a heat radiating plate for radiating the circuit component are assembled by screws to form a circuit component assembly, and a part of the screws is provided on the printed circuit board. A method of mounting a circuit component, wherein the screw and the printed circuit board are fixed by soldering.