JPH06291480A - Electronic circuit module - Google Patents

Abstract

PURPOSE:To increase the cooling efficiency of a higly-heat-generating circuit component and to make an electronic circuit module lightweight. CONSTITUTION:A wick 16 into which a phase-changing fluid is sealed is arranged in a heat sink 3 in which a rectangular hole is made, and a cover 17 is arranged in order to hermetically seal the rectangular hole. A rib 18 is installed in order to prevent the cover 17 from being dented when the rectangular hole sealed hermitically is set to a vacuum state.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic circuit module for electronic equipment mounted on an aircraft or the like, which is characterized by its heat dissipation structure.

[0002]

2. Description of the Related Art The most popular method for cooling electronic circuit components is to blow cooling air directly onto an electronic circuit. However, as the functions of electronic devices have become more and more dispersed in recent years, there is an increasing desire to install the electronic devices themselves in places where environmental conditions are relatively poor. That is, the electronic device is not always installed in a room where temperature, humidity, dust, etc. are restricted as in the past. In such a case, the method of directly blowing the cooling air to the electronic circuit is not preferable in terms of reliability of the electronic device.
This is because dust or the like floating in the cooling air may adhere to the electronic circuit parts, and the adhered parts may corrode or cause dielectric breakdown.

By the way, in electronic equipment mounted on an aircraft, an indirect cooling electronic circuit module is often used in order to prevent deterioration of reliability due to the dust and the like.

Next, a conventional electronic circuit module will be described. FIG. 6 is a front view showing a typical example thereof, and FIG.
It is a figure which shows the cross section CC of FIG. 8 is an external view of an electronic device on which the electronic circuit module shown in FIG. 6 is mounted,
FIG. 9 is a view showing a cross section BB of FIG. In the figure, the electronic circuit module 1 includes a printed wiring board 2, a heat sink 3,
And the IC 4 soldered to the printed wiring board 2;
It is composed of electronic circuit components such as the LSI 5. Here, the heat dissipation plate 3 is made of a metal plate (for example, aluminum alloy) having good thermal conductivity, and is bonded to the back surface of the printed wiring board 2 on which electronic circuit components such as the IC 4 and the LSI 5 are mounted.

A box-shaped chassis 6 for accommodating the electronic circuit module 1 has an opening 7 on the upper surface for removing the electronic circuit module 1. The opening 7 is covered with a cover 8 whose peripheral portion is fixed to the chassis 6 with screws or the like. Opening 7 of the chassis 6
A rectangular ventilation duct 10 is formed by a partition wall 9 on two surfaces that are at right angles to each other and are opposed to each other. Radiating fins 11 are provided inside the ventilation duct 10 and the air duct from the airframe via the external duct 12 The supplied cooling air 13 is designed to flow. Further, on the outer surface of the partition wall 9, there is a U-shaped groove 14 formed so as to form a right angle with the opening portion 7, and the end portion 15 of the electronic circuit module 1 fits into the groove 14. It is inserted from above.

Here, the heat generated from the IC 4 and the LSI 5 is conducted to the printed wiring board 2 and then radiated to the cooling air 13 via the heat radiating plate 3, the partition wall 9 and the heat radiating fin 11. Therefore, the cooling air 13 is not blown directly to the electronic circuit parts of the IC 4 and the LSI 5.

[0007]

In the conventional electronic circuit module 1 as described above, it is necessary to increase the cooling capacity of the heat radiating plate 3 in order to increase the cooling efficiency of the circuit components having high heat generation. For that purpose, the thickness of the heat dissipation plate 3 must be increased. However, there is a limit to the increase in the thickness of the heat dissipation plate 3 depending on the number of electronic circuit modules 1 accommodated in the chassis 6 and the accommodation space of the chassis 6, and the heat dissipation efficiency of the heat dissipation plate 3 is also limited.

Further, the mass of the electronic equipment mounted on the aircraft is controlled in order to obtain the buoyancy of the aircraft, and it is necessary to reduce the weight of all parts constituting the electronic equipment.
Along with this, the electronic circuit module 1 to be mounted on electronic equipment must also be made lightweight.

Further, the electronic equipment mounted on an aircraft must maintain and improve the cooling efficiency of the high heat generating circuit component even under the environment where the acceleration load changes in phase due to the operation of the aircraft.

The present invention has been made in order to solve the above problems, and an object thereof is to obtain an electronic circuit module in which the cooling efficiency of high heat generating circuit components is improved and the weight is reduced.

[0011]

In the electronic circuit module according to the present invention, a rectangular flat hole is provided in a metal heat radiating plate having good thermal conductivity, and a phase-change working fluid is sealed in the hole and a capillary tube is provided. A wick that generates pressure is provided, a cover is provided to seal the rectangular hole, and a rib is provided to prevent the cover from denting when the sealed rectangular hole is vacuumed. The heat radiation plate is provided.

Further, the wick of the heat radiating plate provided with the above means is constituted by a fine metal net which improves the capillary pressure and increases the heat transport amount by the working fluid.

Further, the wick of the heat radiating plate provided with the above means is formed by directly processing a large number of narrow narrow grooves into rectangular holes of the heat radiating plate.

Further, the wick of the heat radiating plate provided with the above means is made of a porous sintered metal which makes the decrease of the capillary pressure minute even when a large acceleration load is applied.

[0015]

In the present invention, by providing the wick in which the working fluid is enclosed in the metal flat radiator plate, the cooling efficiency of the high heat generating circuit component can be improved and the weight of the electronic circuit module can be reduced. Further, by improving the capillary pressure of the wick, it is possible to improve the cooling efficiency even when the acceleration load of an aircraft or the like changes.

[0016]

EXAMPLES Example 1. 1A and 1B are views showing an embodiment of an electronic circuit module according to the present invention. FIG. 1A is a front view, FIG. 1B is a rear view of FIG. 1A, and FIG. It is a figure which shows the cross section AA. In the figure, 1 to 5 are equivalent to conventional electronic circuit modules. Further, 16 is a wick arranged in a rectangular hole provided in the heat dissipation plate 3, and a working fluid 19 that causes a phase change due to a temperature change is enclosed in the wick 16 to seal the rectangular hole. The cover 17 is disposed on the. Wick 1 above
In order to prevent dust or the like floating in the air from entering 6, the sealed rectangular hole is placed in a vacuum state, and in this state, the cover 17 is covered by the difference between the internal pressure and the external pressure of the sealed rectangular hole.
The rib 18 is arranged in a closed rectangular hole to prevent dents.

The electronic circuit module according to the present invention can partially improve the cooling efficiency of the heat sink. Therefore, it is possible to improve the cooling efficiency of the high heat generating circuit component by arranging the rectangular hole in the mounting portion of the circuit component without increasing the thickness of the heat dissipation plate to cool the high heat generating circuit component. Is.

Example 2. FIG. 3 is a sectional view of a rectangular hole of the heat dissipation plate 3 in the electronic circuit module using the invention of the first embodiment. In this invention, as the wick, a fine metal net 20 for improving the capillary pressure and increasing the heat transport amount by the working fluid is arranged in the rectangular hole.

The present invention utilizes the capillary pressure generated from the fine metal net 20 to improve the heat transport capacity of the working fluid enclosed in the wick, and directly to the high heat generating circuit components without directly blowing the cooling air. It is possible to improve the cooling efficiency only by cooling.

Example 3. FIG. 4 shows another embodiment of the present invention and is a cross-sectional view of a rectangular hole of the heat dissipation plate 3 in the electronic circuit module. In the present invention, as the wick described above, a large number of narrow grooves 21 having a narrow width are directly processed into the heat dissipation plate 3.

According to the present invention, it is possible to improve the cooling efficiency only by indirect cooling without directly blowing the cooling air to the high heat generating circuit parts, and since the wick for generating the capillary pressure is directly processed on the heat dissipation plate 3, The weight of the electronic circuit module can be reduced.

Example 4. FIG. 5 shows another embodiment of the present invention and is a cross-sectional view of a rectangular hole of the heat dissipation plate 3 in the electronic circuit module. In the present invention, as the wick described above, the porous sintered metal 22 is arranged in a rectangular hole.

According to the present invention, since the capillary pressure generated by the porous sintered metal 22 is high, it is possible to prevent the capillary pressure from decreasing even when an excessive acceleration load is applied, and improve the cooling efficiency of the high heat generating circuit component. Becomes

[0024]

As described above, according to the present invention, it is possible to increase the cooling efficiency of the high heat generating circuit component and reduce the cooling efficiency of the circuit component by the indirect cooling system in which the direct cooling air is not blown. Therefore, the weight of the electronic circuit module can be reduced.

[Brief description of drawings]

FIG. 1 is a front view of an electronic circuit module according to a first embodiment of the present invention.

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

FIG. 3 is a sectional view of a heat dissipation plate showing a second embodiment of the present invention.

FIG. 4 is a sectional view of a heat dissipation plate showing a third embodiment of the present invention.

FIG. 5 is a sectional view of a heat dissipation plate showing Embodiment 4 of the present invention.

FIG. 6 is a front view showing a conventional representative electronic circuit module.

FIG. 7 is a view showing a cross section CC of FIG. 6;

8 is an external view of a device housing in which the electronic circuit module shown in FIG. 6 is mounted.

9 is a view showing a cross section BB of FIG. 8. FIG.

[Explanation of symbols]

 1 Electronic Circuit Module 2 Printed Wiring Board 3 Heat Sink 4 IC 5 LSI 6 Edge 7 Opening 8 Cover 9 Partition 10 Ventilation Duct 11 Radiating Fin 12 External Duct 13 Cooling Air 14 Groove 15 End 16 Wick 17 Cover 18 Rib 19 Operation Fluid 20 Fine metal mesh wick 21 Multiple narrow narrow groove wick 22 Porous sintered metal wick

Claims (4)

[Claims] 1. A heat-dissipating plate in the form of a metal having good heat conductivity and having a rectangular hole, a wick that is evenly arranged in the rectangular hole and generates capillary pressure, and is enclosed in the wick. Due to the difference between the internal pressure and the external pressure when the sealed rectangular hole is placed in a vacuum state, the working fluid that undergoes a phase change due to the temperature change of the wick, the cover arranged to seal the rectangular hole, An electronic circuit module, comprising: a rib arranged in a longitudinal direction to prevent the cover from being dented. 2. The electronic circuit module according to claim 1, wherein the wick is composed of a fine metal mesh. 3. The electronic circuit module according to claim 1, wherein the wick is formed with a large number of narrow narrow grooves directly on the heat sink. 4. The electronic circuit module according to claim 1, wherein the wick is made of porous sintered metal.