The subject invention is directed toward the art of electronic component housings and, more particularly, to electronic air bag control housings having electromagnetic shielding metal walls provided with a moisture repellant coating. The invention is especially well suited for use with electronic air bag control devices and will be described with particular reference thereto; however, the invention is capable of a broader application and can be used for a variety of purposes in many environments.
Cast aluminum housings provided with threaded sheet metal covers have been used in the past including use in connection with air bag control devices. One disadvantage of cast aluminum housings, however, is that they offer almost no protection from moisture intrusion. For that reason, the electronics contained within the cast aluminum housings must be protected from moisture using any suitable means such as by immersion of the electronic components in an appropriate moisture repellent liquid.
Housings formed in accordance with the above prior art teachings have many drawbacks including poor electromagnetic shielding. In addition, after the printed circuit boards or other electronic components are immersed in the moisture repellent coating, repair of the electronics becomes impossible. Moreover, following the immersion step, there remains the possibility of the unwanted presence of moisture on the printed circuit board remains.
There is, therefore, the need for an electronic components housing of the type described above that is less sensitive to moisture and provides good electromagnetic shielding while also enabling repair of the electronics as necessary.
The subject invention provides an electronic components housing which provides good electromagnetic shielding, electronic component repair friendliness, and an improved moisture sensitivity. The subject housing includes a pair of bent and interconnected sheet metal elements, which are extrusion-coated at least on one side or surface thereof with a plastic covering. A bent sheet metal housing is employed according to the invention, which is subsequently extrusion-coated on one or both sides with a plastic moisture repellent covering. As a beneficial result, the housing is made water-tight. Preferably, the bent and interconnected sheet metal elements are substantially non-flexible. In that regard, any suitable substantially rigid load supporting sheet metal can be used. By means of extrusion coating the sheet metal components with plastic, it is possible to realize a wide range of functional elements in the housing including retention rails for impervious surfaces.
The housing according to the preferred embodiment of the invention is further advantageous in that the most favorable material and/or the most favorable material combination(s) is/are employed for use in the electromagnetic shielding. Preferably, a selectively insertable plug is used in combination with the housing to realize an absolutely water-tight effect. Accordingly, pre-emersion of the printed circuit board into a suitable water repellent liquid is not required. This results in the cost benefit of a reduction in the manufacturing efforts and steps required to construct the housing.
In accordance with a further aspect of the invention, ventilation of the housing is provided using a ventilation membrane.
In accordance with a yet further aspect of the invention, occluded air volume is minimized by suitably shaping the plastic material extruded onto the sheet metal component.
Still a further aspect of the invention is that subsequent repair of the electronic components within the housing remains available.
A primary object of the invention is the provision of an electronic component housing of the type described which includes one or more substantially non-flexible bent and interconnected sheet metal elements which are extrusion-coated on at least one side with a moisture repellent covering of a plastic material.
Yet another object of the invention is the provision of an electronic component housing which enables a printed circuit board or the like to be contained therein in a water-tight state without the need for pre-emersion of the printed circuit board in a water repellent liquid.
Still other advantages and benefits of the invention will become apparent to those of skilled in the art upon a reading and understanding of the following detailed description.