JPH0523593U - Electronic circuit module - Google Patents

Abstract

(57) [Abstract] [Purpose] An electronic circuit module that uses indirect cooling that does not directly blow cooling air to electronic circuit components, has high cooling efficiency, and is capable of equalizing thermal stress of electronic circuit components. [Structure] For two skins 2 made of a rectangular metal thin plate, an inlet 9 for cooling air 8 is provided on one side of the skin 2.
Further, the outlet portion 10 for the cooling air 8 is provided on the side opposite to the one side.
And a spacer 3 is attached so as to be sandwiched between the skin 2 and the peripheral portion of the skin 2, and inside the duct 7 surrounded by the skin 2 and the spacer 3 near the inlet portion 9. The outlet part 1
A cylindrical cooling fin 11 that becomes dense near 0
By disposing, the heat exchange efficiency between the columnar cooling fin 11 and the cooling air 8 can be improved as the temperature of the cooling air 8 rises. [Effect] The thermal stress of the electronic circuit component 5 can be equalized,
Further, it is possible to realize an electronic circuit module having an efficient heat dissipation structure that does not increase the frictional resistance when the cooling air 8 flows in the duct 7 more than necessary.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 This invention relates to an improvement of an electronic circuit module, and is characterized by its cooling structure.

[0002]

[Prior Art]

 The most common method for cooling electronic circuit components has been to blow cooling air directly onto the electronic circuit components. However, as functions in the field of electronic devices have become more and more decentralized in recent years, there is a growing desire to install electronic devices themselves even in locations with relatively poor environmental conditions. In other words, electronic devices are not always installed in a room in which temperature, humidity, dust, etc. are controlled as in the conventional case. In such a case, the method of directly blowing the cooling air to the electronic circuit component is not preferable in terms of reliability of the electronic device. This is because dust floating in the cooling air adheres to electronic circuit parts, which may corrode or cause dielectric breakdown.

By the way, in an electronic device mounted on an aircraft, an indirect cooling electronic circuit module is often used in order to prevent deterioration of reliability due to dust as described above. FIG. 3 is a typical example thereof, and is an external view of an electronic circuit module which is generally called a heat desiccator module and which has an excellent effect of heat dissipation while being cooled by cooling. 4 is a diagram showing a cross section AA in FIG. 3, and FIG. 5 is a diagram showing a cross section BB in FIG. In the figure, 1 is a cooling fin formed by corrugating a metal having good heat conductivity such as aluminum alloy, 2 is a skin of a rectangular thin metal plate brazed or adhered to both sides of the cooling fin 1, and 3 is a spacer. The cooling fin 1 is arranged between two skins, and is joined to the skin 2 by brazing or adhesion. Reference numeral 4 denotes a printed wiring board, one surface of which is bonded to the skin 2, and the other surface of which is mounted an electronic circuit component 5 and a connector plug 6. Cooling air 8 flows in a duct 7 surrounded by the cooling fins 1, skins 2 and spacers 3, and the cooling air 8 flows in from an inlet portion 9 of the duct and flows out from an outlet portion 10 of the duct. Here, the heat generated from the electronic circuit component 5 is guided to the cooling fin 1 via the printed wiring board 4 and the skin 2 by heat conduction, and is radiated to the cooling air 8 flowing in the duct 7. . That is, the electronic circuit module 5 is an indirect cooling electronic circuit module in which the cooling air 8 is not directly blown, and as described above, it is widely used in electronic equipment mounted on aircraft where reliability is important. It is what

[0004]

[Problems to be solved by the device]

 The conventional electronic circuit module as described above has the following problems. That is, the heat stress applied to the electronic circuit component 5 is not uniform and the heat stress is small in the one arranged near the inlet portion 9, while the one arranged near the outlet portion 10 receives a large heat stress. become. This is because the temperature of the cooling air 8 gradually rises due to the heat generated from the electronic circuit component 5, so that when the cooling air 8 flows through the duct 7, the temperature becomes higher toward the downstream side. In order to improve the heat transfer characteristics of the cooling fins 1, the pitch of the cooling fins 1 (P in FIG. 3) should be made fine and the heat radiation area should be increased, but this makes the heat stress uniform. It is not possible. Moreover, if the pitch of the cooling fins 1 is made fine as described above, the frictional resistance when the cooling air 8 flows in the duct 7 increases, and a large load is imposed on the blower device for supplying the cooling air 8 to the electronic circuit module. You will be forced.

The present invention has been made in order to solve the above problems, and an object thereof is to obtain an electronic circuit module that can equalize the thermal stress of electronic circuit components.

[0006]

[Means for Solving the Problems]

 The electronic circuit module according to the present invention has two skins made of rectangular thin metal plates, one side of the skin has an inlet for cooling air, and the other side has an outlet for cooling air. A spacer is attached so that it can be formed and sandwiched by the peripheral portion of the skin, and in the duct surrounded by the skin and the spacer, sparsely near the inlet portion and also at the outlet portion. The columnar cooling fins are arranged so as to be dense near the.

[0007]

[Action]

 In this invention, the cooling fins having a cylindrical shape are sparsely arranged near the inlet of the duct, and the cooling fins are densely arranged near the outlet, so that the cooling fins having the cylindrical shape and the cooling air are increased as the temperature of the cooling air rises. It is possible to improve the heat exchange efficiency with the heat exchange, which makes it possible to equalize the heat stress of the electronic circuit components. Further, since the frictional resistance when the cooling air flows in the duct will not be increased more than necessary, the blower for supplying the cooling air will not be overloaded.

[0008]

【Example】

 Example 1. 1 is an external view showing an embodiment of the present invention, and FIG. 2 is a view showing a cross section CC of FIG. In the figure, 2 to 10 are the same as the conventional electronic circuit module, and therefore the description thereof is omitted. Reference numeral 11 denotes a columnar cooling fin made of a metal having a good thermal conductivity such as an aluminum alloy, and a large number of cooling fins are arranged in the duct 7. The cylindrical cooling fin 11 as described above has recently been attracting attention due to its excellent heat dissipation efficiency. The reason for this is that technical improvements in recent precision casting methods (for example, lost wax casting method). Along with that, it seems that one of the reasons is that it has come to be realized by means of high productivity.

Here, the cylindrical cooling fins 11 are not evenly arranged in the duct 7, but are rough at the upstream side of the flow of the cooling air 8 (that is, near the inlet portion 9) and the downstream flow of the flow ( That is, they are densely arranged near the outlet portion 10). As described above, the cooling air 8 that has flowed in from the inlet 9 of the duct is sequentially warmed by the heat generated from the electronic circuit component 5, and becomes hot near the outlet 10. Therefore, as in the present embodiment, the columnar cooling fins 11 are densely arranged near the outlet 10 to improve the heat transfer characteristic to the cooling air 8. The efficiency will be equalized. Considering only the improvement of cooling efficiency, it suffices to densely arrange the cylindrical cooling fins 11 in the entire area of the duct 7. In this case, the frictional resistance when the cooling air 8 flows in the duct 7 is reduced. It is not a preferable method because it increases more than necessary.

[0010]

[Effect of the device]

 Since the electronic circuit module according to the present invention is configured as described above, it is possible to cool the electronic circuit components more evenly and realize an efficient cooling structure.

[Brief description of drawings]

FIG. 1 is an external view showing an electronic circuit module according to the present invention.

FIG. 2 is a view showing a cross section CC of FIG.

FIG. 3 is an external view showing a conventional electronic circuit module.

FIG. 4 is a diagram showing a cross section AA of FIG. 3;

5 is a diagram showing a cross section BB of FIG. 3. FIG.

[Explanation of symbols]

 1 Cooling Fin 2 Skin 3 Spacer 4 Printed Wiring Board 5 Electronic Circuit Parts 6 Connector Plug 7 Duct 8 Cooling Air 9 Inlet 10 Outlet 11 Cylindrical Cooling Fin

Claims (1)

[Scope of utility model registration request] 1. Two skins made of a rectangular thin metal plate,
One side of the skin has an inlet for cooling air, and
Arranged in the peripheral part of the skin so that the side opposite to the side forms an outlet part for cooling air,
And a spacer provided so as to be sandwiched by the two skins, and provided in a duct surrounded by the two skins and the spacer, and sparsely near the first opening, and Closely arranged cylindrical cooling fins near the second opening, and two printed wirings in which electronic circuit components are mounted on one surface and the other surface is adhered to the skin An electronic circuit module characterized by being composed of a board.