Water Spray-Resistant, Ventilated Housing Structure

Abstract

To protect electronic components located within a housing structure, or casing, which contains ventilation openings, against corrosion due to intrusion of water, for example being sprayed thereon upon cleaning of the area on which the structure is mounted, the housing is formed with an attachment surface having ventilation ducts formed therein which are generally Y-shaped having two branch ducts terminating at the outside of the housing in spaced position, and forming an angle with respect to each other, for example terminating at essentially right angled housing edges, and a third trunk duct connected to the interior of the housing, and branching off from the two branch ducts, so that water sprayed against the housing may run through the branch ducts, without impingement on a back wall, and ventilation is provided by additional movement of air through the trunk of the Y-shaped duct; the ducts are preferably mounted with respect to the housing in such a manner that any liquid which might accumulate within the housing structure, due to condensation, can drain off, that is, can flow out through one of the branch ducts by gravity. The present invention relates to a housing structure which is so constructed that it contains ventilating openings, and yet is resistant to intrusion by water, or other liquids which may be sprayed against the housing structure, or in the immediate vicinity, and more particularly to a housing structure for electronic apparatus, especially for electronic apparatus to be used in automotive vehicles. Electronic apparatus used in automotive vehicles is frequently mounted in the engine compartment; the apparatus is thus subjected to the rough environmental conditions of the motor vehicle itself. Frequently it is located at a position where it is accessible for testing or servicing, thus at a position which is not well protected. The electronic components within the housing may include various electronic elements such as semiconductors, capacitors, resistors, integrated circuits, and other electronic elements which are mounted on organic or inorganic carrier substrates, such as XXXP circuit boards, epoxy-glass fiber substrates or carriers, ceramic substrates, or the like. It is important that water and high atmospheric humidity be excluded from the interior of the housing, in order to prevent corrosion and to retain the high insulation resistances of the electronic elements as well as of the carrier plates themselves. Hermetically sealing the housing is one solution which, however, is expensive, leads to cooling difficulties, and is, in general, commercially not suitable. Ventilating the housing prevents establishment within the housing of peculiar climatic conditions within the housing itself. It has previously been proposed to include electronic apparatus in housings which are formed with ventilating ducts so constructed that they form a tortuous, or labyrinth path from the outside into the housing. Spray water used to clean surrounding areas may, however, penetrate into such apparatus through the ventilating path, even if the duct itself has various turns or changes of directions, particularly if a stream of water directly impinges on the ventilating duct. It is particularly difficult to prevent penetration of water into the housing if pressure of a water spray or stream directed against the housing or surrounding area is high, or if the spray time is comparatively long. This condition may obtain, for example, when pressure-cleaning the engine compartment of a motor vehicle. It is an object of the present invention to provide a housing structure for electronic apparatus, and an electronic apparatus, in general, which is so constructed that water will not penetrate thereinto even if a stream of water is directed against the ventilating opening itself. Briefly, the ventilating duct is so constructed that, in the projection of the back side of the housing, it is essentially Y-shaped, with the two branches of the Y terminating at the edges of the housing to form a through-duct; the trunk of the Y is connected to the interior of the housing, that is, to an internal ventilating duct; the two branches of the Y terminate at different sides of the housing. The structure of the present invention, therefore, provides a through-duct for water which is directed against the ventilating opening of the housing, to prevent reflection, or ricochet effects of streams of water directed against any one of the ventilating openings, the trunk of the Y branching off at the direction which is preferably so located that any water penetrating therein will, automatically, drain off. In accordance with a feature of the invention, the branch ducts terminating at the edges of the housing have approximately the same size, or diameter, or diametrical area. The housing is so located on the branch ducts that they terminate at the lowest point of the housing, to provide for drainage of water by gravity. Additionally, and in accordance with a preferred feature, the trunk duct leading to the interior of the housing is formed with a constriction, that is, tapers, in funnel form, to a constricted point and then extends to an opening which is perpendicular to the direction of the trunk duct, the trunk duct enlarging, again, to enhance the funnel effect. The opening leading into the interior of the housing, preferably, is curved, for example formed as a circular segment.

Patent Drawings (1 sheets)

Sheet 1