Housing for electrical equipment

Abstract

To provide a housing for electrical equipment in which condensation is suppressed over a long period of time, and in which the degree of freedom in the placement of the electrical equipment is high, and the manufacturing cost can be reduced.SOLUTION: The housing for electrical equipment having an installation unit in which the electrical equipment can be installed includes a housing unit having the installation unit on the inner surface and a molded body provided in contact with the inner surface of the housing unit, having a thermal conductivity at 25°C of 0.3 W / m K or higher and 1.0 W / m K or lower, and being placed at least opposite the installation unit.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a housing for an electrical device.

Background Art

[0002] Conventionally, in a housing for an electrical device mounted on a vehicle or the like, electrical devices such as power semiconductors and power modules are housed inside the housing portion.

[0003] Due to the heat generation of the electrical devices housed inside the housing portion, the temperature inside the housing for the electrical device rises. When the electrical device is cooled by the low-temperature outside air in this state, condensation occurs on the inner surface of the housing portion. The greater the temperature difference between the inside and the outside of the housing for the electrical device, the easier it is for condensation to occur. Also, when the airtightness of the housing for the electrical device is high, the air pressure inside the housing for the electrical device increases as the temperature rises, so the dew point temperature rises and condensation is likely to occur. And when the water droplets generated by condensation adhere to the electrical device, it may cause leakage or corrosion, and the electrical device may malfunction. Therefore, it is required to suppress condensation occurring inside the housing for the electrical device.

[0004] For example, Patent Document 1 describes an electrical device including an electronic component, a control board for controlling the electronic component, a capacitor connected to the electronic component, a discharge resistor for discharging the charge stored in the capacitor, and a box-shaped housing for housing these electronic components, control board, capacitor, and discharge resistor. In the electrical device of Patent Document 1, the upper portion of the housing above the control board is defined as the upper housing portion, and the discharge resistor is provided in contact with the inner surface of the upper housing portion. In Patent Document 1, by keeping the inner surface of the upper housing portion warm by the heat generation of the discharge resistor, the temperature difference between the inner surface of the housing and the inside of the housing is suppressed, and the occurrence of condensation on the inner surface of the housing is suppressed.

[0005] In addition, Patent Document 2 describes a dew condensation prevention heat retention mechanism for a device having an electric circuit including a device housing metal frame that constantly retains heat of an electric device, a heating element that warms in contact with the device housing metal frame, temperature detection means for detecting the temperature of the device housing metal frame, control means for controlling the temperature of the heating element from the temperature detection means, an electric circuit part through which heat is transmitted in contact with the device housing metal frame, an electric circuit board through which heat is transmitted in contact with the electric circuit part, an operation switch that operates the electric circuit part under the control of the control means, and a device housing exterior part that protects the device housing metal frame. In Patent Document 2, a heater, which is a heating element, is used to retain heat of the housing, suppress the temperature difference between the inner surface of the housing and the inside of the housing, and suppress the occurrence of dew condensation on the inner surface of the housing.

[0006] In addition, Patent Document 3 describes an electric connection box installed in a device, the electric connection box having a heat insulation layer provided in a portion of the inner wall of the electric connection box that becomes the upper part when the device is installed. In Patent Document 3, the heat insulation layer on the inner wall of the connection box suppresses the decrease in the surface temperature of the inner wall of the connection box and suppresses the occurrence of dew condensation.

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0008] However, in Patent Document 1, by providing a discharge resistor in contact with the inner surface of the upper part of the housing, it is possible to suppress water droplets generated by dew condensation from falling and adhering to a control board located below the inner surface of the upper part of the housing. However, since it is necessary to provide a discharge resistor in the upper part of the housing, there are many design restrictions such as the arrangement of each electrical component and circuit board.

[0009] In Patent Document 2, a heater, which is a heating element, is used to suppress the occurrence of dew condensation. Since the heater is expensive, there is room for improvement in terms of the recent demand for reducing manufacturing costs.

[0010] In Patent Document 3, a foam heat insulation layer is provided in a portion that becomes the upper part when installed on equipment on the inner wall of an electrical connection box to suppress the occurrence of dew condensation. The foam and fibrous heat insulation layers have pores. Therefore, once dew condensation occurs, the porous heat insulation layer has a problem of retaining moisture in the pores and causing further dew condensation.

[0011] In this way, in Patent Documents 1 to 3, there has been a problem that the occurrence of dew condensation cannot be suppressed over a long period, the degree of freedom in arranging electrical equipment is low, and manufacturing costs cannot be reduced.

[0012] An object of the present disclosure is to provide a housing for an electrical device in which the occurrence of dew condensation is suppressed over a long period, the degree of freedom in arranging electrical equipment is high, and manufacturing costs can be reduced.

Means for Solving the Problems

[0013] [1] A housing for an electrical device having an installation portion where an electrical device can be installed, the housing including a housing portion having the installation portion on an inner surface thereof, and a molded body provided in contact with the inner surface of the housing portion, the molded body having a thermal conductivity at 25°C of 0.3 W / m·K or more and 1.0 W / m·K or less and being disposed at least opposite to the installation portion. [2] The molded body according to [1] above, including a resin base material and a plurality of latent heat storage materials dispersed in the resin base material, the melting point of the latent heat storage materials being 40°C or more and 80°C or less. [3] The housing for an electrical device according to [2] above, wherein the plurality of latent heat storage materials are composed of two or more types of latent heat storage materials having different melting points. [4] The housing for an electrical device according to any one of [1] to [3] above, wherein the molded body is not porous.

Effects of the Invention

[0014] According to the present disclosure, it is possible to provide a housing for an electric device in which the occurrence of condensation is suppressed over a long period, the degree of freedom in arranging the electric device is high, and the manufacturing cost can be reduced.

Brief Description of the Drawings

[0015]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Embodiments for Carrying Out the Invention

[0016] Hereinafter, a detailed description will be given based on the embodiments.

[0017] The housings 1 and 2 for electrical equipment according to the embodiments are housings for electrical equipment having an installation portion 41 on which an electrical equipment 40 can be installed, and include a housing portion 10 having the installation portion 41 on its inner surface, and molded bodies 20, 20a, 20b, 20c which are provided in contact with the inner surface 10a of the housing portion 10, have a thermal conductivity at 25°C of 0.3 W / m·K or more and 1.0 W / m·K or less, and are disposed at least opposite to the installation portion 41.

[0018] (First Embodiment) FIG. 1 is a schematic view showing an example of the housing for electrical equipment according to the first embodiment. FIG. 2 is a schematic view showing the state of temperature related to the occurrence of dew condensation in the housing for electrical equipment. FIG. 3 is a schematic view showing a housing for electrical equipment not including the molded bodies constituting the housing for electrical equipment. FIG. 4 is a schematic view showing an example of the molded bodies constituting the housing for electrical equipment.

[0019] As shown in FIGS. 1 and 2, the housing 1 for electrical equipment according to the first embodiment has an installation portion 41 inside on which the electrical equipment 40 can be installed, and includes a housing portion 10 and a molded body 20. The electrical equipment 40 can be installed inside the housing 1 for electrical equipment. The housing 1 for electrical equipment is mounted on, for example, a vehicle or the like.

[0020] The housing portion 10 has the installation portion 41 on its inner surface 10a. The housing portion 10 is the housing of the housing 1 for electrical equipment and is made of, for example, metal. The housing portion 10 is a rectangular parallelepiped as shown in FIG. 1 here.

[0021] The electrical equipment 40 installed on the installation portion 41 is a power module or the like with a large heat generation amount, such as an ECU (Engine Control Unit), a DC-DC converter, or an inverter.

[0022] Further, the housing 1 for electrical equipment includes an opening 30 that communicates the inside and the outside of the housing portion 10. A ventilation filter 31 is provided in the opening 30.

[0023] An installation portion 41 is provided on the inner surface of the housing portion 10. For example, when the electrical device 40 is an ECU, the outer surface side of the wall portion where the installation portion 41 is provided is fixed to the engine room of the vehicle or the like. Therefore, the electrical equipment housing 1 will also tilt according to the tilt of the vehicle.

[0024] The molded body 20 is provided in contact with the inner surface of the housing portion 10. Further, as shown in FIG. 1, the molded body 20 is disposed at least opposite to the installation portion 41. In a state where the electrical device 40 is installed inside the electrical equipment housing 1, the molded body 20 disposed opposite to the electrical device 40 and the installation portion 41 does not contact the electrical device 40.

[0025] By disposing the molded body 20 at least opposite to the installation portion 41, the molded body 20 having heat insulation properties and latent heat storage properties insulates the inner surface 10a of the housing portion 10, stores the heat radiated from the electrical device 40 as latent heat, keeps the inner surface 10a of the housing portion 10 warm, and can efficiently suppress a rapid temperature change of the inner surface 10a of the housing portion 10. Therefore, the occurrence of condensation inside the electrical equipment housing 1 can be suppressed. Furthermore, since the occurrence of condensation can be sufficiently suppressed without separately installing a heating element such as a heater, the degree of freedom in arranging the electrical devices inside the electrical equipment housing 1 can be increased, and the manufacturing cost can be reduced.

[0026] The molded body 20 may be provided on the entire inner surface 10a of the housing portion 10, for example, on the entire inner surface 10a of the housing portion 10 excluding the inner surface of the wall portion provided with the installation portion 41.

[0027] For example, the molded body 20 can be attached in close contact with the inner surface 10a of the housing portion 10 by installing a double-sided adhesive tape or a leaf spring on the inner surface 10a of the housing portion 10.

[0028] Further, the molded body 20 has heat insulation properties and latent heat storage properties, and the thermal conductivity at 25 ° C is 0.3 W / m·K or more and 1.0 W / m·K or less.

[0029] When the thermal conductivity of the molded body 20 is 0.3 W / m·K or more, it has a thermal conductivity equal to or higher than that of the latent heat storage material encapsulated in the molded body 20, efficiently transfers the heat from the electric device 40 such as a heat generating device to the latent heat storage material, and the heat storage efficiency becomes good. Further, the effect of heating the electric device housing 1 with the stored heat can also be obtained. Also, when the thermal conductivity of the molded body 20 is 1.0 W / m·K or less, it has a heat insulating effect on the metal material constituting the housing portion 10. Further, from the above viewpoints, the thermal conductivity of the molded body 20 is preferably lower than the thermal conductivity of the housing portion 10.

[0030] As shown in FIG. 4, the molded body 20 includes a resin base material 21 and a plurality of latent heat storage materials 22 dispersed in the resin base material 21. The melting point of the latent heat storage material 22 is preferably 40° C. or higher and 80° C. or lower. The molded body 20 in which a plurality of latent heat storage materials 22 are dispersed in the resin base material 21 has a high degree of freedom in shape, excellent handleability, and further good heat storage properties.

[0031] Also, inside the electric device housing 1, the temperature rises due to the heat generated during the operation of the electric device 40. When the melting point of the latent heat storage material 22 is equal to or lower than the rising temperature inside the electric device housing 1, latent heat effective for temperature holding can be obtained. Also, since the electric device housing 1 is cooled by the outside air temperature, the melting point of the latent heat storage material 22 is preferably higher than the outside air temperature throughout the year. From such viewpoints, the melting point of the latent heat storage material 22 is preferably 40° C. or higher and 80° C. or lower.

[0032] The resin base material 21 preferably has heat insulating properties on the inner surface 10a of the housing portion 10 made of metal, and further, is composed of a material having a high insulation resistance value, excellent electrical insulation properties, good heat resistance and durability against the heat generation temperature of the electric device. The resin base material 21 includes, for example, polyethylene, polypropylene, silicone, urethane, epoxy, acrylic, olefin, phenol, polyimide, synthetic rubber such as ethylene propylene diene rubber (EPDM), and the like.

[0033] As the latent heat storage material 22 dispersed in the resin base material 21, a microcapsule-type latent heat storage material, a granular solid crystal transition-type latent heat storage material, or a resin material having latent heat storage properties, trans-1,4 polybutadiene, is preferable.

[0034] For example, as the microcapsule-type latent heat storage material 22, microcapsules encapsulating a solid-liquid phase transition latent heat storage material paraffin in a melamine resin shell, and as the granular latent heat storage material, a strong electron correlation compound and the like can be mentioned. Examples of the strong electron correlation compound include vanadium dioxide (VO2) and vanadium oxides doped with tungsten (W), rhenium (Re), ruthenium (Ru), niobium (Nb), tantalum (Ta), etc. in VO2.

[0035] By mixing and molding the latent heat storage material 22 with the resin base material 21, a molded body 20 having good heat insulation and latent heat storage properties can be easily manufactured.

[0036] The molded body 20 is preferably not porous. If the molded body 20 is porous such as a foam or fibrous, the water absorption increases, so the effect of suppressing dew condensation decreases.

[0037] The molded body 20 stores and releases heat by repeating melting and solidification in the latent heat storage material 22. The molded body 20 has latent heat at the melting point of the latent heat storage material 22 and stores or releases high thermal energy. A latent heat storage material 22 with an appropriate melting point is appropriately selected according to the heat generation temperature and heat generation amount of the electric device 40.

[0038] For example, as shown in FIGS. 5 and 6, a molded body 20a in which a latent heat storage material 22a having a melting point lower than that of the latent heat storage material 22 is dispersed in the resin base material 21, or a molded body 20b in which a latent heat storage material 22b having a melting point lower than that of the latent heat storage material 22a is dispersed in the resin base material 21 may be appropriately selected.

[0039] Further, as shown in FIG. 7, it is preferable that the plurality of latent heat storage materials are composed of two or more kinds of latent heat storage materials having different melting points. Here, a molded body 20c including three kinds of latent heat storage materials 22, 22a, and 22b having different melting points is shown, but the molded body 20c may include two kinds of latent heat storage materials having different melting points, or may include four kinds of latent heat storage materials having different melting points.

[0040] Next, a mechanism for suppressing dew condensation inside the housing for an electric device will be described with reference to FIGS. 2 and 3.

[0041] The housings 1 and 100 for electric devices are cooled by the low-temperature outside air L1, and the temperature of the inner surface 10a of the housing portion 10 decreases. Further, when the electric device 40 is installed in the installation portion 41 of the housings 1 and 100 for electric devices and the electric device 40 operates, the temperature inside the housing 1 for electric devices rises due to the heat dissipation flow L2 from the electric device 40.

[0042] In the housing 100 for an electric device that does not include the molded body 20, the air heated by the heat dissipation flow L2 from the electric device 40 is likely to be below the dew point, so dew condensation 60 is likely to occur on the inner surface 10a of the housing portion 10. The greater the temperature difference between the temperature of the inner surface 10a of the housing portion 10 and the temperature inside the housings 1 and 100 for electric devices, the more likely dew condensation 60 is to occur on the inner surface 10a of the housing portion 10. The molded body 20 having heat insulation properties and latent heat storage properties has a thermal conductivity within the above numerical range and has low thermal conductivity, and a heat insulation effect can be obtained. Therefore, it is possible to suppress an increase in the temperature difference between the temperature of the inner surface 10a of the housing portion 10 and the inside of the housing 1 for electric devices, so the air inside the housing 1 for electric devices is less likely to be below the dew point, and an effect of suppressing the occurrence of dew condensation 60 generated on the inner surface 10a of the housing portion 10 over a long period can be obtained.

[0043] In addition, the molded body 20 having heat insulation properties and latent heat storage properties stores the heat radiated from the electrical equipment 40 as latent heat, keeps the inner surface 10a of the housing part 10 warm, and suppresses a rapid temperature change of the inner surface 10a of the housing part 10. Therefore, it is possible to suppress an increase in the temperature difference between the temperature of the inner surface 10a of the housing part 10 and the inside of the electrical equipment housing 1, so that the air inside the electrical equipment housing 1 is less likely to drop below the dew point, and the generation of dew condensation 60 occurring on the inner surface 10a of the housing part 10 can be suppressed over a long period of time.

[0044] In addition, the electrical equipment housing 1 preferably includes an opening 30 having a ventilation filter 31 that preferably balances the pressure between the inside air and the outside air. By balancing the pressure between the inside air and the outside air of the electrical equipment housing 1, the dew point temperature drops, and the generation of dew condensation 60 inside the electrical equipment housing 1 can be suppressed. When the difference between the temperature inside the electrical equipment housing 1 and the outside air temperature is small, the ventilation between the inside air and the outside air of the electrical equipment housing 1 becomes insufficient, and dew condensation is likely to occur. When the rise in the internal temperature of the electrical equipment housing 1 is low, the above ventilation becomes insufficient. By providing the molded body 20 having heat insulation properties and latent heat storage properties inside the electrical equipment housing 1, the internal temperature of the electrical equipment housing 1 rises and the ventilation efficiency is increased. Furthermore, due to the heat insulation and heat preservation effects of the inner surface 10a of the housing part 10 described above, the suppression of dew condensation generation inside the electrical equipment housing 1 can be strengthened.

[0045] As described above, according to the electrical equipment housing 1 of the first embodiment, by installing the molded body 20 having the above characteristics facing the installation part where the electrical equipment can be installed inside the housing part 10, the generation of dew condensation inside the housing part 10 can be suppressed over a long period of time. In addition, the generation of dew condensation can be sufficiently suppressed without providing a heating element such as a heater as in the prior art. Therefore, compared with the prior art, the electrical equipment housing 1 can improve the degree of freedom in arranging electronic devices accommodated inside and reduce the manufacturing cost.

[0046] Incidentally, in the above description, as shown in FIG. 1, an example of a housing for an electrical device is described in which the molded body 20 is installed at the upper part of the drawing sheet, and the installation part 41 where the electrical device 40 can be installed is arranged at the lower part of the drawing sheet, that is, in the direction of gravity. However, an arrangement configuration as shown in FIG. 8 may also be used. That is, in the housing 1 for an electrical device shown in FIG. 8, the installation part 41 is arranged on one side wall of the drawing sheet, the molded body 20 is arranged opposite on the other side wall of the drawing sheet, and the molded body 20 is arranged at the upper part of the drawing sheet, that is, above the direction of gravity. The housing 1 for an electrical device with such an arrangement configuration can more efficiently suppress the occurrence of condensation caused by the heat dissipation flow L2 of the electrical device 40.

[0047] (Second Embodiment) FIG. 9 is a schematic diagram showing an example of a housing for an electrical device according to the second embodiment.

[0048] In the housing 2 for an electrical device according to the second embodiment, the configuration is basically the same as that of the housing 1 for an electrical device according to the first embodiment, except that the arrangement configuration of the molded body 20 is different. Therefore, here, the different configuration will be mainly described.

[0049] As shown in FIG. 9, the housing 2 for an electrical device includes a plurality of types of molded bodies having different physical properties in at least one of thermal conductivity and melting point. Among the plurality of types of molded bodies, the thermal conductivities are different, the melting points are different, or both the thermal conductivity and the melting point are different. Here, the housing 2 for an electrical device includes a molded body 20 having a higher melting point and a molded body 20a having a lower melting point than the molded body 20, with the melting points being different from each other.

[0050] According to the heat generation amount of the electrical equipment 40 housed in the housing 2 for electrical equipment and the temperature rise inside the housing 2 for electrical equipment in winter and summer, a plurality of types of molded bodies 20, 20a with different melting points are arranged. For example, according to the type of the electrical equipment 40, the heat generation amount of the electrical equipment 40 is different. Compared with power modules with large heat generation amounts such as ECUs, DC-DC converters, and inverters, the heat generation amount of control boards and power supply boards is small. Also, in winter, since the temperature rise inside the housing 2 for electrical equipment is low, the latent heat of the molded body 20a having the low melting point latent heat storage material 22a is utilized, and in summer, since the temperature rise inside the housing 2 for electrical equipment is high, the latent heat of the molded body 20 having the high melting point latent heat storage material 22 is utilized. Thus, throughout the year, by appropriately arranging a plurality of types of molded bodies 20 with different melting points according to the type of the electrical equipment 40 and the like, the molded bodies 20, 20a can efficiently store the heat from the electrical equipment 40. Therefore, the cooling of the internal temperature of the housing 2 for electrical equipment by the low-temperature outside air is delayed, and the occurrence of dew condensation inside the housing part 10 can be efficiently suppressed.

[0051] As described above, according to the housing for electrical equipment of the second embodiment, by arranging a plurality of types of molded bodies having different physical properties of at least one of the thermal conductivity and the melting point according to the internal temperature of the housing for electrical equipment and the heat generation situation of the electrical equipment, the heat from the electrical equipment can be efficiently stored. Therefore, the occurrence of dew condensation in the housing for electrical equipment can be further suppressed.

[0052] Although the embodiments have been described above, the present invention is not limited to the above embodiments, includes all aspects included in the concept of the present disclosure and the scope of the claims, and can be variously modified within the scope of the present disclosure.

Explanation of Reference Numerals

[0053] 1, 2, 100 Housing for electrical equipment 10 Housing part 10a Inner surface of the housing part 20, 20a, 20b, 20c Molded body 21 Resin base material 22, 22a, 22b Latent heat storage material 30 Opening 31 Ventilation filter 40 Electrical equipment 41 Installation part 60 Condensation

Claims

1. A housing for an electrical device having an installation portion where the electrical device can be installed, the housing portion having the installation portion on its inner surface and being made of metal, a molded body provided in contact with the inner surface of the housing portion, having a thermal conductivity at 25°C of 0.3 W / m·K or more and 1.0 W / m·K or less, having a lower thermal conductivity than that of the housing portion, and being disposed opposite to at least the installation portion with a space therebetween and comprising a housing for an electrical device.

2. The housing for an electrical device according to Claim 1, wherein the installation portion is arranged in the direction of gravity.

3. The housing for an electrical device according to Claim 1 or 2, wherein the installation portion is provided at the lower part of the housing portion, and the molded body is provided at the upper part of the housing portion.

4. The housing for an electrical device according to any one of Claims 1 to 3, further comprising an opening having a ventilation filter for balancing the pressure between the inside air and the outside air.

5. The molded body includes a resin base material and a plurality of latent heat storage materials dispersed in the resin base material, and the melting point of the latent heat storage material is 40°C or more and 80°C or less. The housing for an electrical device according to any one of Claims 1 to 4.

6. The housing for an electrical device according to Claim 5, wherein the plurality of latent heat storage materials are composed of two or more kinds of latent heat storage materials having different melting points.

7. The housing for an electrical device according to any one of Claims 1 to 6, wherein the molded body is not porous.

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