JPH0582092U - Heat dissipation structure for heat-generating electronic components - Google Patents

Abstract

(57) [Summary] [Purpose] The heat generated by the heat-generating electronic components can be radiated well, and the temperature rise inside the case is suppressed. [Structure] The printed wiring board 2 is arranged in the lower case 1B. A heat radiating portion 3 made of a material having good thermal conductivity is provided on the upper surface of the upper case 1A, and the main body 10A of the resistor 10 forming a heat generating electronic component is directly fixed to the inner surface of the heat radiating portion 3. The compression coil springs 12a and 12b made of a conductive material are mounted on the leads 11a and 11b of the resistor 10, and the springs are pressed against the lands 9A and 9B formed on the printed wiring board 2 to form the lands 9A and 9B and the leads. Electrical connection with 11a and 11b is aimed at.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a heat dissipation structure for heat-generating electronic components in small electronic devices and the like.

[0002]

[Prior Art]

 With the high-density mounting of electronic devices, how to handle the heat generated from heat-generating electronic components has become a major issue. In particular, as a heat dissipation structure for heat-generating electronic components such as power transistors and resistors mounted on a printed wiring board housed in the case, conventionally, natural air cooling with the outside air or forced air cooling (heat is generated from the hole opened in the case Emitted to the outside), mounted on a high thermal conductive board (diffuses heat of heat-generating electronic components over the entire board to make it uniform), devises component arrangement on the board (distance heat-sensitive components from heat-generating electronic components, etc.), A heat pipe or heat dissipation fin is attached to the heat generating electronic components (the heat of the components is released to the air in the case), and the surface area of the heat generating electronic components is increased (the heat radiation performance of the components themselves is improved).

[0003]

[Problems to be solved by the device]

 However, if the amount of heat generated by the heat-generating electronic components is too large for the volume of the case, none of the above heat dissipation structures is sufficient, and if the case is increased according to the amount of heat generated, the electronic device itself There was a problem that it led to an increase in size. Further, when a case having a hermetically sealed structure is required for reasons such as electrostatic breakdown and intrusion of dust, there is a problem that the above structure cannot be adopted.

Therefore, the present invention has been made in view of the above-mentioned conventional problems, and an object thereof is to satisfactorily dissipate the heat generated by the heat-generating electronic components to the outside of the case. Another object of the present invention is to provide a heat dissipation structure for heat-generating electronic components that can suppress the temperature rise inside the case, especially in the printed wiring board.

[0005]

In order to achieve this object, a heat dissipation structure for a heat-generating electronic component according to the present invention is the heat dissipation structure for a heat-generating electronic component on a printed wiring board housed in a case. Has a heat-dissipating part which is made of a material having good thermal conductivity and is exposed to the inside and outside of the case, at least a part of which has its main body fixed to the heat-dissipating part. The land portion provided on the printed wiring board is electrically connected by an elastic member made of a conductive material.

[0006]

[Action]

 In the present invention, the heat-dissipating part of the case is directly adhered and fixed to the heat-dissipating part, so that the thermal resistance between the heat-dissipating electronic part and the outside air is greatly reduced, and the heat generated from the heat-dissipating electronic part is directly dissipated to the outside of the case. To do. The elastic member electrically connects the lead and the land portion and reduces the amount of heat transferred from the heat-generating electronic component to the printed wiring board.

[0007]

【Example】

 Hereinafter, the present invention will be described in detail with reference to the embodiments shown in the drawings. FIG. 1 is an exploded perspective view showing an embodiment of a heat dissipation structure for heat-generating electronic components according to the present invention, and FIG. 2 is a sectional view. In these figures, reference numeral 1 denotes a case for accommodating a printed wiring board 2. The case 1 is formed into two parts, that is, a shallow box-type upper case 1A whose lower surface is open and a shallow case whose upper surface is open. It is composed of a box-shaped lower case 1B. The upper case 1A is made of resin, and the heat dissipation portion 3 is provided at the center of the upper surface. The heat radiating portion 3 is made of a material having good thermal conductivity, for example, an aluminum plate, and is integrally formed at the same time as the molding of the upper case 1A by insert molding so that the opening 4 provided at the center of the upper surface of the upper case 1A is formed. It is airtightly closed and the upper surface is exposed to the outside of the case. A fitting convex portion 6a and a fitting concave portion 6b are formed over the entire circumference on the lower end surface of the upper case 1A, that is, the joint surface with the lower case 1B. The lower case 1B is entirely made of resin, and board supporting portions 7a and 7b for supporting the lower surface of the printed wiring board 2 are integrally projectingly provided on the inner bottom surface thereof. Further, on the upper opening end surface of the lower case 1B, a fitting concave portion 8a and a fitting convex portion 8b capable of fitting with the fitting convex portion 6a and the fitting concave portion 6b of the upper case 1A are provided all around. Is formed. The upper case 1A and the lower case 1B are configured to house the printed wiring board 2 and fit each other, and then are integrally coupled by a set screw or the like (not shown). The method of attaching the heat radiating portion 3 is not limited to insert molding, and it is also possible to previously provide an opening in the upper case 1A and attach the heat radiating portion 3 with a set screw or heat staking.

A conductive foil 9 forming an electric circuit is printed on the upper surface of the printed wiring board 2, and various electronic parts such as a resistor 10 forming a heat-generating electronic part, a capacitor, a transistor and a diode (not shown). Is mounted on the supporting portions 7a and 7b of the lower case 1B and is fixed by a set screw (not shown). The resistor 10 is composed of a rectangular parallelepiped main body 10A and inverted L-shaped leads 11a and 11b respectively provided on both end faces of the main body 10A. The leads 11a, 11b are located above the printed wiring board 2 and spaced apart from the board, while being closely attached to the inner surface and fixed by spot welding, screwing, bonding, brazing, or the like. Compression coil springs 12a and 12b made of a highly conductive metal material are attached to the vertical portions extending below the leads 11a and 11b, and these compression coil springs 12a and 12b are When the printed wiring board 2 is housed and arranged in the lower case 1B, the resistor 10 is arranged on the inner surface of the heat dissipation portion 3, and when the upper and lower cases 1A and 1B are integrally coupled, the lower end is compressed and the printed wiring board is The lands 9A and 9B of the conductive foil 9 formed on the substrate 2 are pressed against each other with sufficient contact resistance, thereby connecting the resistor 10 to the electric circuit of the printed wiring board 2. When assembling the case 1, the upper case 1A to which the resistor 10 is attached is placed upside down, the compression coil springs 12a and 12b are attached to the leads 11a and 11b, and then the lower case containing the printed wiring board 2 is housed. 1B is turned upside down and fitted into the upper case 1A, and then both cases 1A and 1B are fastened and fixed with set screws.

Thus, in the heat dissipation structure for the heat-generating electronic component having such a configuration, the resistor 10 which is the heat-generating electronic component is directly fixed to the inner surface of the heat dissipation portion 3 provided on the upper surface of the upper case 1A. Therefore, the thermal resistance between the resistor 10 and the outside air is significantly reduced, and the heat generated by the resistor 10 can be radiated favorably to the outside of the case 1. Further, in the present invention, the leads 11a, 11b are not directly connected and fixed to the lands 9A, 9B but are electrically connected via the compression coil springs 12a, 12b. The amount of heat transferred to the printed wiring board 2 via the leads 11a and 11b can be greatly reduced, and the temperature rise of the board can be prevented.

FIG. 3 is a sectional view showing another embodiment of the present invention. In this embodiment, the entire upper case 1A is formed by pressing an aluminum plate to form a heat dissipation portion, and a leaf spring formed by bending a substantially U-shaped metal material having good conductivity instead of the compression coil spring. 15a and 15b are interposed between the land portions 9A and 9B and the lower ends of the leads 11a and 11b, and the other structures are the same as those in the above-described embodiment. The leaf springs 15a and 15b are soldered and fixed to the lands 9A and 9B in advance, and are elastically deformed by the lower ends of the leads 11a and 11b when the upper case 1A is mounted on the lower case 1B and assembled. As a result, sufficient contact resistance is generated between the leads 11a and 11b, and the reliability of connection is secured. Even with such a configuration, the same effect as that of the above embodiment can be obtained.

4 (a) to 4 (c) show still another embodiment of the present invention. (A) The figure shows an example in which the leaf springs 15a, 15b bent and formed in a substantially J shape are spot-welded to the leads 11a, 11b so as to elastically contact the lands, (b) The figure shows a heat-generating electronic component. As an example, the present invention is applied to a power transistor 20 having three leads 11a, and an example in which a compression coil spring 12a is attached to each lead as in the embodiment shown in FIGS. 1 and 2, (c) is a diagram. A lead insertion hole 21 is formed in the center of the land portion 9A so as to penetrate the printed wiring board 2, the lower end portion of the lead 11a is inserted into this hole 21, and the land portion 9A and the lead 11a are electrically charged by a compression coil spring 12a. An example in which they are physically connected is shown.

[0012]

[Effect of the device]

 As described above, according to the heat dissipation structure of the heat-generating electronic component of the present invention, at least a part of the case is provided with the heat dissipation part exposed to the inside and outside by the material having good heat conductivity, and the heat dissipation part is provided on the inner surface thereof. Since the electronic components are directly fixed and the leads of the heat-generating electronic components and the lands of the printed wiring board are electrically connected by the elastic member made of a conductive material, the heat-generating electronic components are not connected to the outside air. It is possible to significantly reduce the thermal resistance of the and significantly improve the heat dissipation effect, and also to greatly reduce the amount of heat transferred to the printed wiring board. As a result, it is possible to suppress the temperature rise in the case, and thereby prevent the heat resistance temperature of other components mounted on the printed wiring board from being exceeded. In addition, since the case has a simple structure and can be manufactured and provided at low cost, and the case can have a closed structure, electrostatic breakdown, dust intrusion, and the like can be prevented.

[Brief description of drawings]

FIG. 1 is an exploded perspective view showing an embodiment of a heat dissipation structure for heat-generating electronic components according to the present invention.

FIG. 2 is a sectional view of the same structure.

FIG. 3 is a cross-sectional view showing another embodiment of the present invention.

4 (a) to 4 (c) are a perspective view, a perspective view and a cross-sectional view of a main part, showing still another embodiment of the present invention.

[Explanation of symbols]

 1 Case 1A Upper Case 1B Lower Case 2 Printed Wiring Board 3 Heat Dissipation Parts 9A, 9B Land Part 10 Resistors 11a, 11b Leads 12a, 12b Compression Coil Springs

Front page continuation (72) Kozo Uga, 1-4, Fujimi-cho, Gyoda-shi, Saitama Prefecture, within Jeco Co., Ltd.

Claims (1)

[Scope of utility model registration request] 1. A heat dissipation structure for a heat-generating electronic component on a printed wiring board housed in a case, wherein at least a part of the case has a heat dissipation part exposed to the inside and outside of the case, The main body of the heat-generating electronic component is fixed to the heat radiating portion, and the lead of the heat-generating electronic component and the land portion provided on the printed wiring board are electrically connected by an elastic member made of a conductive material. A heat dissipation structure for heat-generating electronic components.