JPH0617355Y2 - Heat sink mounting structure for printed wiring board - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial field of application) The present invention relates to a heat sink mounting structure for a printed wiring board.

(Prior Art) As a heat sink mounting structure for a printed wiring board, for example, one shown in FIG. 4 is known. According to this heat sink mounting structure, a rectangular heat sink 100 made of a metal plate having excellent heat transferability such as aluminum is arranged on the printed wiring board 200 in an upright state, and one side portion of the heat sink 100 is disposed. A horizontally bent leg piece 110 is provided at the base end, the fixing leg piece 110 is fixed to the printed wiring board 200 with a screw 300, and a leg piece 120 is provided at the other side base end of the heat dissipation plate 100. This leg piece 120 is inserted into a positioning hole 210 provided in the printed wiring board 200, and a part thereof is projected.

In this way, the transistor 400 mounted on the printed wiring board 200 is fixed to the heat dissipation plate 100 mounted on the printed wiring board 200.
The heat generated from 00 is radiated.

(Problems to be Solved by the Invention) The printed wiring board 200 is mounted on an electronic component such as a transistor 400 and then sent to an automatic soldering device to be soldered while passing through a solder bath. In this case, the heat sink 100 is made of aluminum, and the portion of the leg piece 120 that protrudes from the positioning hole 210 should not have solder, but the burr or the like formed on the leg piece 120 when the heat sink 100 was manufactured. In some cases, the solder may adhere to the scratched portion of the above, and thereafter, the solder piece attached to the scratched portion of the leg piece 120 may peel off due to vibration or the like to cause a short circuit or the like.

Therefore, conventionally, the printed wiring board 200 is sent to an automatic soldering device, and after the soldering is completed, the heat sink 100
Was fixed on the printed wiring board 200.

However, the printed wiring board 20 that has been soldered
When installing the heat sink 100 to 0, the transistor 400
Since this is already soldered, this transistor 40
It is necessary to fix the heat sink 100 to the transistor 400 by hand while paying attention not to remove the solder of 0, and to fix the heat sink 100 to the printed wiring board 200, which is very troublesome and the assembly efficiency is high. Was difficult to improve.

This invention solves the above-mentioned problems of the prior art. The purpose of this invention is that even if the heat sink is fixed before sending the printed wiring board to the automatic soldering device, solder is attached to the legs of the heat sink. It is an object of the present invention to provide a heat sink mounting structure for a printed wiring board, which does not wear and does not have a problem of causing a short circuit or the like and can improve the assembly efficiency.

[Constitution of device]

(Means for Solving the Problems) In order to achieve the above object, in the present invention, a heat dissipation plate having an electronic component mounted and fixed thereon is arranged in a standing state on a printed wiring board, and a lead wire of the electronic component is connected to the printed wiring board. While projecting to the wiring conductor side from the hole provided in the plate, one side base end of the heat dissipation plate is fixed by a fastening means such as a screw, and a leg piece provided on the other side base end of the heat dissipation plate is attached. In a radiator mounting structure for a printed wiring board configured to allow the wiring conductor side to pass over a solder bath in a state where it is inserted into a positioning hole provided in the printed wiring board, solder is applied to the inner wall of the positioning hole. A metal layer that can be attached is provided, and the leg pieces are formed to have a length that does not protrude from the positioning hole.

(Operation) After fixing the heat dissipation plate on the printed wiring board, when the printed wiring board is sent to the automatic soldering device, the solder adheres to the metal layer on the inner wall of the positioning hole to close the positioning hole, and the legs of the heat dissipation plate are closed. Solder does not adhere to the piece.

Embodiment An embodiment of the present invention will be described below with reference to the drawings.

1 to 3 show an embodiment of the present invention,
FIG. 1 is a front view, FIG. 2 is a perspective view, and FIG. 3 is an enlarged sectional view of a main part. In the figure, reference numeral 10 is a heat dissipation plate, and 20 is a printed wiring board.

The heat radiating plate 10 is formed in a square shape by a metal plate such as aluminum having a good heat transfer property, and has a leg piece 11 for fixing which is bent substantially horizontally at the base end of one side part thereof, and the other side. Positioning leg pieces 12 extending vertically are provided at the base ends of the parts. The transistor 40 mounted on the printed wiring board 20 is fixed to the central portion of the heat dissipation plate 10 with a screw 50.

Here, the leg piece 11 has a screw hole 1 into which a screw 30 inserted from a fixing hole 22 provided in the printed wiring board 20 is screwed.
1a is provided. The leg pieces 12 are formed to have a length that does not protrude from the positioning holes 21 provided in the printed wiring board 20. In addition, a metal layer 21a of copper, nickel or the like, to which solder can be attached, is attached to the inner wall of the positioning hole 21.
Is formed by a plating means such as chemical plating,
The positioning hole 21 has a through hole structure.

The heat radiating plate 10 is arranged in an upright state on the surface portion of the printed wiring board 20 where the wiring conductors 23 are not provided, and the leg pieces 11 of the heat radiating plate 10 are fixed by the screws 30 inserted into the fixing holes 22. In addition, the leg pieces 12 are inserted into the positioning holes 21 of the printed wiring board 20.
The lead wire 41 of the transistor 40 is inserted into the hole 24 provided in the printed wiring board 20 and protrudes to the side where the wiring conductor 23 is provided.

The printed wiring board 20 to which the heat sink 10 is fixed in this way is sent to an automatic soldering device, where the wiring conductor 23
The side provided with is the lower side and passes over the solder bath, and the lead wire 41 of the transistor 40 and the lead wires of other electronic components are soldered to the wiring conductor 23.

At this time, the solder 60 also adheres to the metal layer 21a on the inner wall of the positioning hole 21, and the bottom of the positioning hole 21 (the opening on the side where the wiring conductor 22 is provided) is closed by the solder 60. . For this reason, solder does not adhere to scratches such as burrs formed on the leg pieces 12 when the heat sink 10 is manufactured. Then, a part of the leg piece 12 is embedded in the solder 60 that closes the positioning hole 21, and is fixed so as not to rattle.

Therefore, the solder pieces attached to the leg pieces 12 will not be peeled off by vibration or the like to cause an accident such as a short circuit.
That is, there is no problem even if the printed wiring board 20 is sent to the automatic soldering device and soldered while the heat sink 10 is fixed. Therefore, the heat radiating plate 10 is fixed while paying attention so that the solder does not come off to the transistor 40 on the printed wiring board 20 that has been soldered by hand, and the heat radiating plate 10 is fixed to the printed wiring board 20. It is not necessary to do anything, and it is possible to significantly improve the efficiency of assembly work.

In the above-described embodiment, the positioning hole 21 has a through-hole structure by using a plating means to form the positioning hole 2
Although the case where the metal layer 21a is formed on the inner wall of No. 1 is shown, the invention is not limited to this. For example, an eyelet metal fitting may be inserted and the metal layer 21a may be formed by this eyelet metal fitting.

[Effect of device]

As described above, according to the present invention, the metal layer to which solder can be attached is provided on the inner wall of the positioning hole of the printed wiring board, and the leg of the heat dissipation plate is formed to have a length that does not protrude from the positioning hole. , As in the conventional method, the heat radiating plate is fixed to the electronic parts on the printed wiring board after soldering, taking care not to remove the solder, and it is troublesome to fix the heat radiating plate to the printed wiring board. Without requiring work, even if the printed wiring board is sent to the automatic soldering device with the heat sink fixed, solder does not adhere to the legs of the heat sink,
Assembling efficiency can be improved without the problem of causing a short circuit.

[Brief description of drawings]

1 to 3 show an embodiment of the present invention,
FIG. 1 is a front view, FIG. 2 is a perspective view, FIG. 3 is an enlarged cross-sectional view of an essential part, and FIG. 4 is a perspective view showing a conventional technique. 10 ... Heat sink 20 ... Printed wiring board 12 ... Leg 21 ... Positioning hole 21a ... Metal layer 30 ... Tightening means (screws) such as screws

Claims (1)

[Scope of utility model registration request] 1. A heat radiating plate, on which electronic components are mounted and fixed, is arranged in an upright state on a printed wiring board, and lead wires of the electronic components are projected from a hole provided in the printed wiring board toward a wiring conductor. A state in which the base end of one side of the heat sink is fixed by tightening means such as a screw, and the leg piece provided on the base end of the other side of the heat sink is inserted into a positioning hole provided in the printed wiring board. In the heat sink mounting structure in the printed wiring board configured to pass the wiring conductor side over the solder bath, a metal layer to which solder can be attached is provided on the inner wall of the positioning hole, and the leg pieces are A heat sink mounting structure for a printed wiring board, characterized in that the heat sink mounting structure is formed so as not to protrude from the positioning hole.