JPH1013044A - Electronic part case - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent electronic parts from being short-circuited due to water drops generated by dew formation in an electronic part case for housing electronic parts inside the case. SOLUTION: Heat-insulation layers 16 and 18 are formed on the inner surface of an electronic part case 10 for housing electronic parts 22, 24, and 26 excluding its one portion. A part where the heat-insulation layers 16 and 18 are not provided becomes a part 20 with a higher thermal conductivity between the outside and the inside of the case 10 than in the other parts. When temperature around the case 10 decreases, the temperature of the part 20 with a high thermal conductivity decreases most rapidly on the inner surface of the case. Therefore, this part forms dew first, the amount of saturation steam decreases inside the case, and no dew is formed on the other parts, especially electronic parts. Also, dews formed at the part 20 with a high thermal conductivity drip, are drained from a drain hose 28 provided directly below to the outside of the case, thus preventing the electronic parts from being wetting by dewdrops.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic component case for storing electronic components and protecting the electronic components from dust, water, heat, and the like, and more particularly, to the structure thereof.

[0002]

2. Description of the Related Art Electronic components used in outdoor equipment are housed in a substantially hermetically sealed case in order to protect them from dust and water. For example, Japanese Unexamined Patent Publication
Japanese Patent Application Laid-Open No. 245542 discloses a technique in which a power supply unit such as an inverter used for an electric vehicle is disposed in a substantially sealed case.

[0003]

As in the apparatus disclosed in the above publication, dew condensation occurs in a substantially sealed case when the surrounding environment changes, that is, when the surrounding temperature drops rapidly. When water drops generated by the condensation fall on the electronic components housed in the case, there is a problem that the electronic components are short-circuited and damaged. It is also conceivable that dew may be directly formed on the electronic component. In this case, a short circuit occurs.

In order to solve this problem, it is conceivable to completely seal the case. However, in this case, it is difficult to completely seal a portion of the case in which a lead from an electronic component is guided to the outside. In this case, an increase in cost cannot be avoided. In addition, it is conceivable to completely cover the electronic component with silicon grease or the like so as not to be short-circuited even if water droplets are applied. However, in this case as well, the cost and weight increase.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and provides an electronic component case having a simple configuration and capable of preventing occurrence of a short circuit of electronic components due to dew condensation in the case. The purpose is to do.

[0006]

In order to achieve the above-mentioned object, an electronic component case according to the present invention has a high thermal conductivity portion having a higher thermal conductivity between the outer surface of the case and the inner surface of the case than other portions. The high thermal conductivity portion is provided at a position where the dewed water droplet does not directly drop on the electronic component when dew condensation occurs here.

[0007] The present invention has the above configuration,
The temperature of the inner wall surface of the case becomes the lowest in the high thermal conductivity portion, for example, when the ambient temperature is rapidly reduced. Therefore, the water vapor inside the case is condensed on the high thermal conductivity portion. If dew condensation occurs in the high thermal conductivity portion, the amount of saturated water vapor in the case decreases, so that dew condensation on other portions, for example, directly on electronic components is prevented. And even if the dew formed in the high thermal conductivity portion becomes a water droplet, it is located at a position where it does not directly drop on the electronic component, so that a short circuit of the electronic component can be prevented.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments (hereinafter, referred to as embodiments) of an electronic component case according to the present invention will be described below with reference to the drawings.

FIG. 1 shows an electronic component case 1 according to the present embodiment.
0 embodiments are shown. The electronic component case 10 includes a lower case 12 and an upper case 14, and the upper case 14 serves as a lid of the lower case 12 to substantially seal the inside of the case. This closed state is not a completely closed state for preventing air from flowing outside and inside the case 10, but a closed state for preventing dust and water from entering from the outside. The lower case 12 has a metal main body 12a, and a heat insulating layer 16 is formed on the entire side surface inside the main body 12a. The upper case 14 has a metal main body 14a, and a heat insulating layer 18 is provided on almost the entire surface except for a part of the main body 14a. The portion where the heat insulating layer 18 is not provided is a portion where the metal of the upper case body 14a is exposed to the inside, so that the heat conductivity of the outside and inside of the case in this portion is higher than other portions. Therefore, the portion of the upper case 14 where the heat insulating layer 18 is not formed becomes the high thermal conductivity portion 20.

In the electronic component case 10, a power device 22, a capacitor 24, and a printed circuit 26, which are electronic components, are housed. In particular, the power device 22 that generates a large amount of heat is provided in contact with the bottom of the case and radiates heat from the bottom of the case. A cooling pipe (not shown) for performing liquid cooling such as water cooling is provided on the bottom surface of the case. A drain hose 28 is attached to the bottom surface of the lower case 12 directly below the high thermal conductivity portion 20.

When the temperature around the electronic component case 10 of the present embodiment decreases, the temperature of the inner wall of the case 10 becomes higher than that of the portion where the heat insulating layers 16 and 18 are provided.
The temperature decreases faster. Although the bottom surface of the lower case 12 is not provided with the heat insulation layers 16 and 18, the heat capacity of the liquid in the cooling pipe is large, and the temperature of this portion is relatively hard to decrease due to the residual heat of the power generator 22. Therefore, the temperature of the inner wall of the high thermal conductivity portion 20 becomes lowest, and dew condensation first occurs in this portion. Therefore,
The occurrence of dew condensation directly on the electronic component is prevented. Then, dew condensation generated in the high thermal conductivity portion 20 drops as water droplets. The water droplets are received by the drain hose 28 and discharged to the outside of the case 10, and do not hit the electronic components.

Further, as shown in FIG. 2, a conical member 30 can be provided in the high thermal conductivity portion 20. 2, the same components as those in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted. The conical member 30 is preferably made of a material having a high thermal conductivity. It is more preferable that the conical member 30 be made of a metal having the same quality as that of the upper case body 14a. The dew condensation generated on the surface of the conical member 30 drips from the top of the conical member 30 into the drain hose 28 and does not reach the electronic components. In addition, since dew condensation occurs on the conical member 30, it is possible to prevent dew condensation directly on the electronic component.

As shown in FIG. 3, a conical member 32 is provided on the high thermal conductivity portion 20 and a chain 34 is formed from the apex of the conical member 32.
Can be arranged so as to hang inside the drain hose 28. 3, the same components as those in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted. The conical member 32 is formed of a member having a high thermal conductivity such as a metal. Dew condensation generated on the surface of the conical member 32 is dripped into the drain hose 28 along the chain 34 from the apex of the conical member 32. Therefore, Case 1
0 is discharged to the outside and does not hit the electronic parts. The material of the chain 34 is not particularly limited. However, if a non-conductive material such as a resin is used, it is possible to prevent the chain 34 from contacting the printed circuit 26 or the like for some reason and causing a short circuit. The chain 34 does not have to have a correct chain shape, and may be a simple linear component as long as water droplets can be guided into the drain hose 28. In addition, since dew condensation occurs on the conical member 32, it is possible to prevent dew condensation from occurring directly on the electronic component.

FIG. 4 shows an embodiment in which a drain hose is not provided with respect to the embodiment shown in FIG. 4, the same components as those in FIG. 1 are denoted by the same reference numerals, and description thereof is omitted. In the present embodiment, the high thermal conductivity portion 20
A water-absorbing member 36 such as a polymer absorbent is disposed immediately below the water-absorbing member, and the water that has condensed and dropped is absorbed here. Therefore, the dropped water does not accumulate on the bottom surface or scatter, and does not splash on the electronic components. In addition, since dew condensation occurs in the high thermal conductivity portion 20, it is possible to prevent dew condensation from occurring directly on the electronic component. Further, it is also preferable to make the water absorbing member 36 replaceable. In this case, even if the water absorbing member does not absorb water due to dirt or the like, the function can be restored by replacing the water absorbing member.

In the above embodiment, it is preferable to form a groove for guiding water to the drain hose 28 on the bottom surface of the lower case 12. In this case, the high thermal conductivity portion 20 may be formed not only immediately above the drain hose 28 but also above the groove.

FIG. 5 shows still another embodiment. 5, the same components as those in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted. The feature of this embodiment is that a high thermal conductivity portion 38 is provided on a part of the side surface of the lower case 12. The high thermal conductivity portion 38 is formed vertically long so that the lower end reaches the bottom surface. Therefore, the water droplets condensed here reach the bottom surface along the side surface, and can be more reliably guided to the drain hose 28, and can be drained to the outside of the case 10. Therefore, water drops do not fall on the electronic components. In addition, since dew condensation occurs in the high thermal conductivity portion 38, it is possible to prevent dew condensation from occurring directly on the electronic component.

In each of the embodiments described above, the heat insulating layers 16 and 18 may be formed by adhering a highly heat-insulating plate member such as a resin containing a large amount of air bubbles to the inner surface of the case 10. Further, a foaming resin is sprayed on the inner surface to form the heat insulating layer 1.
6, 18 may be formed. Further, in each of the above-described embodiments, the heat insulating layer is not provided in a part in order to provide the high thermal conductivity part. However, the high thermal conductivity can also be obtained by making the thickness of the case wall thinner than other parts. A part can be provided. In addition, by forming a part of the case main body with a member having higher thermal conductivity than the surroundings, a high thermal conductivity portion can be formed.

[Brief description of the drawings]

FIG. 1 is a diagram showing a schematic configuration of a preferred embodiment of an electronic component case according to the present invention.

FIG. 2 is a diagram showing another embodiment according to the present invention.

FIG. 3 is a diagram showing still another embodiment according to the present invention.

FIG. 4 is a diagram showing still another embodiment according to the present invention.

FIG. 5 is a view showing still another embodiment according to the present invention.

[Explanation of symbols]

10 electronic component case, 12 lower case, 14 upper case, 16, 18 heat insulation layer, 20, 38 high thermal conductivity part.

Claims (1)

[Claims] An electronic component case accommodating an electronic component therein, wherein the case has a high thermal conductivity portion having a higher thermal conductivity between an outer surface of the case and an inner surface of the case than other portions of the case. The electronic component case, wherein the rate portion is provided at a position where water droplets that have condensed do not directly drop onto the electronic component when condensation occurs here.