JPH0714695U - Heat dissipation structure for electronic devices - Google Patents

Abstract

(57) [Abstract] [Purpose] To obtain a heat dissipation structure for an electronic device or the like that has a sufficient heat dissipation area and does not require a work space for a tool such as a screw driver to be provided on a printed circuit board. [Structure] A heat radiating plate 5 made of a metal plate having good thermal conductivity is installed on a fixed substrate such as a printed circuit board C.
In a heat dissipation structure of an electronic device or the like for cooling the power device 3 by contacting the surface of the power device 3, the heat dissipation plate 5 having a top wall 5b is formed, and the power device 3 is contacted with the inner surface of the side wall 5a of the heat dissipation plate 5, The base end portion 8b of the holding metal fitting 8 for pressing the tip end portion 8a against the surface of the power device 3 through the release portion 9 formed at the boundary portion between the side wall 5a and the top wall 5b of the heat dissipation plate 5 is attached to the top wall 5b. A heat dissipation structure for electronic devices etc.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a cooling structure for a power device incorporated in electronic equipment, and more particularly to a heat dissipation structure for a power device mounted on a fixed substrate such as a printed substrate.

[0002]

[Prior art]

Generally, electronic devices have built-in power devices such as power transistors, FET devices, and diodes, but these power devices are usually mounted on a printed circuit board together with various circuit devices. Therefore, conventionally, heat dissipation plates A ₁ and A ₂ as shown in FIG. 3 or 4 are used to prevent the temperature rise of the power devices B ₁ and B ₂ . That is, in FIG. 3, a strip-shaped heat sink A ₁ is installed facing the power device B ₁ mounted on the printed circuit board C, and a fixing screw D is attached to the surface of the heat sink A ₁ made of a metal plate having good thermal conductivity. _The power device B ₁ is brought into close contact with the spring material restraining tool E fixed at ₁ , and the anchor a which is integrally molded with the heat dissipation plate A ₁ is fixed to the ground conductor (not shown) of the printed circuit board C. . Further, FIG. 4 is directly fixed to the heat radiating tip b of the power device B ₂ in the same manner on the surface of the heat radiating plate A ₂ using the fixing screws D _2, grounding conductor of the anchor a for the heat radiating plate A ₂ PCB C It is an example of being fixed and connected to (not shown).

[0003]

[Problems to be solved by the device]

However, since the holding metal E and the fixing screws D ₁ and D ₂ do not contribute to the cooling of the power devices B ₁ and B ₂ , the heat dissipation area of these conventional heat dissipation structures is substantially the same as that of the heat dissipation plates A ₁ and A ₂ . The surface area is too small to sufficiently cool the power devices B ₁ and B ₂ with the small heat sinks A ₁ and A ₂ , and the temperature of the power devices B ₁ and B ₂ rises above the rating, which easily causes a failure.

In the above-described heat dissipation structure, a tool such as a screw driver is inserted from a direction parallel to the surface of the heat dissipation plates A ₁ and A ₂ of the printed circuit board C, and the fixing screws D ₁ and D ₂ are tightened. However, there is a problem in that the mounting density of the circuit elements on the surface of the printed board C is lowered by securing the insertion space for the screw driver or the like.

In view of the problems of the conventional heat dissipation structure as described above, an object of the present invention is to secure a work space for a tool such as a screw driver, which has a sufficient heat dissipation area, on a printed circuit board. This is to obtain a heat dissipation structure for unnecessary electronic devices.

[0006]

[Means for Solving the Problems]

 In order to achieve this object, the present invention installs a heat sink made of a metal plate with good thermal conductivity on a fixed substrate such as a printed circuit board, and cools the power device by contacting the surface of the heat sink. In a heat dissipation structure for electronic equipment, etc., the heat dissipation plate having a ceiling wall is molded, and the power device is brought into contact with the inner surface of the side wall of the heat dissipation plate to form an opening portion formed at the boundary between the sidewall of the heat dissipation plate and the ceiling wall. It is proposed to screw the base end portion of the holding metal fitting through which the tip end portion is pressed against the surface of the power device to the ceiling wall.

[0007]

【Example】

 Hereinafter, the embodiment of the present invention will be described in detail with reference to FIGS. The illustrated embodiment is an example in which the present invention is applied to an AC power supply adapter of a word processor. Inside the adapter case 1, there are a transformer transformer 2, circuit elements such as a rectifying diode 3 which is one of power devices, a smoothing capacitor 4 and the like. A printed circuit board C for mounting is mounted.

On the surface of the same printed circuit board C, a heat dissipation plate 5 having a gate-shaped cross section that straddles the entire printed circuit board C is fixed by a mounting screw 6. The cross-sectional shape of the heat dissipation plate 5 made of a metal plate having a good thermal conductivity such as aluminum is not limited to the gate shape for the purpose of the present invention, and is an inverted "L" having a side wall 5a and a ceiling wall 5b. It may be formed in the shape of a letter.

In detail, a rectifying diode 3 covered with a protective tube 7 having good thermal conductivity is in contact with the inner surface of the side wall 5a of the heat dissipation plate 5, and the side wall facing the rectifying diode 3 is in contact with the side wall 5a. At the boundary between 5a and the top wall 5b, a release portion 9 into which the tip portion 8a of the restraint fitting 8 can be inserted from above is formed. Further, a fixing hole 10 is formed in the base end portion 8b of the holding metal fitting 8 made of a thin metal plate having a spring property, and a fixing screw 11 is tightened on the surface of the top wall 5b corresponding to the fixing hole 10. A screw hole 12 that can be formed is formed.

Since the heat dissipation structure according to the illustrated embodiment has the above-described structure, when the holding metal fitting 8 is tightened by using the fixing screw 11 from the direction perpendicular to the printed circuit board C, the elasticity of the holding metal fitting 8 causes The rectifying diode 3 is brought into close contact with the inner surface of the heat dissipation plate. In this case, the fixing of the rectifying diode 3 to the heat sink 5 can be completed simply by causing the screw driver to act on the fixing screw 11 from a direction perpendicular to the surface of the printed circuit board C. It is not necessary to secure a working space on the surface of the printed circuit board C for the purpose of tightening, and the mounting density of the printed circuit board C can be improved. Further, when tightening the fixing screw 11, since the fixing work can be performed while visually observing the relationship between the tip 8a of the holding metal fitting 8 and the rectifying diode 3, the protective tube 7 which is also an insulating object may be damaged. Disappear.

Of course, it is needless to say that the radiating plate 5 formed in the inverted “L” -shaped cross section has a wide radiating area, so that the rectifying diode 3 can be surely prevented from overheating.

[0012]

[Effect of device]

 As is clear from the above description, according to the heat dissipation structure of the present invention, not only the heat dissipation plate having a sufficient heat dissipation area can be obtained, but also the work of fixing the holding metal can be performed from the direction perpendicular to the printed board. Since this can be done, the mounting density on the printed circuit board is increased, and this work has the advantage that it can be done while surely observing the tip of the holding metal fitting.

[Brief description of drawings]

FIG. 1 is a top view of an AC adapter to which the present invention is applied, which is shown with a part cut away.

FIG. 2 is an enlarged perspective exploded view of a main part inside the AC adapter. FIG. 6 is a perspective view of a heat dissipation structure according to a third embodiment of the present invention.

FIG. 3 is a perspective view of a conventional heat dissipation structure.

FIG. 4 is a perspective view of another conventional heat dissipation structure.

[Explanation of symbols]

 C Printed circuit board 3 Rectifying diode (power device) 5 Heat sink 5a Side wall 5b Top wall 8 Suppression metal fitting 8a Tip part 8b Base end part 9 Release part 11 Fixing screw

Claims (1)

[Scope of utility model registration request] 1. A heat dissipation structure for an electronic device, etc., in which a heat dissipation plate made of a metal plate having good thermal conductivity is installed on a fixed substrate such as a printed circuit board, and a power device is brought into contact with the surface of the heat dissipation plate for cooling. In, the heat dissipation plate having a ceiling wall is formed, and the power device is brought into contact with the inner surface of the side wall of the heat dissipation plate,
It is characterized in that the base end portion of the restraining metal fitting for pressing the tip end against the surface of the power device through the release portion formed at the boundary between the side wall and the top wall of the heat sink is screwed to the top wall. Heat dissipation structure for electronic devices.