Abstract:
The present invention provides an assembly for protecting automotive electronics. The assembly includes a circuit board, a cover, and a metal housing. The metal housing is disposed over and around the circuit board. The cover and metal housing are crimped together to create a seal that protects the circuit board inside the metal housing and attaches the cover to the metal housing.

Description:
BACKGROUND 
     1. Field of the Invention 
     The present invention generally relates to an assembly for protecting electronic components. 
     2. Description of Related Art 
     Powertrain control modules are currently packaged in diverse mechanical configurations. Such mechanical configurations often involve expensive custom die cast and stamp metal covers bonded to other custom polymeric or metal parts to protect the electronic assembly. Powertrain control modules must be designed to operate in harsh, under hood environmental conditions. Yet the high volume required to fulfill an automotive application also requires a cost effective design. The current cost of a typical aluminum die cast housing may represent a significant cost of the overall module. In addition, stamped metal and die cast covers are susceptible to gaps between the top and bottom covers increasing susceptibility to environmental conditions and electromagnetic interference. Further, plastic configurations may offer no electromagnetic interference protection at all. 
     In view of the above, it is apparent that there exists a need for an improved assembly for protecting electronic components. 
     SUMMARY 
     In satisfying the above need, as well as, overcoming the enumerated drawbacks and other limitations of the related art, the present invention provides an assembly for protecting automotive electronics. The assembly includes a circuit board, a cover, and a metal housing. The metal housing is disposed over and around the circuit board. The cover and metal housing are crimped together to create a seal that protects the circuit board inside the metal housing and attaches the cover to the metal housing. 
     In another aspect of the present invention, the metal housing may be a deep drawn metal housing, or alternatively a rolled metal sheet joined at two ends to create a seam that is welded or soldered. In addition, the metal housing may be coated with an anti-corrosive material. To provide thermal dissipation and support the circuit board, a surface in the form of a groove or trough extending inward from the metal housing towards the circuit board. 
     In another aspect of the present invention, the cover may include an electrical connector providing electrical communication with the circuit board from outside the assembly. Further, the electrical connector may be molded into the cover thereby providing improved sealing between the cover and the connector. 
     In another aspect of the present invention, the crimped region attaching the cover to the metal housing extends along the entire perimeter or along substantially the entire perimeter between the metal housing and the cover. The enlarged region includes a portion of the metal housing and a portion of the cover crimped together forming mating surfaces on the metal housing and the flange, thereby attaching the metal housing to the cover. 
     Further objects, features and advantages of this invention will become readily apparent to persons skilled in the art after a review of the following description, with reference to the drawings and claims that are appended to and form a part of this specification. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a top view of an assembly for protecting electronic components in accordance with the principles of the present invention; 
         FIG. 2  is an assembly utilizing a rolled metal sheet to form a housing for protecting electronic components in accordance with the principles of the present invention; 
         FIG. 3  is a sectional side view of the assembly with the metal housing having portions to support the circuit board and aid in thermal dissipation; 
         FIGS. 4A and 4B  are a sectional side view of the crimped region illustrating a rolled crimp in accordance with the principles of the present invention; 
         FIGS. 5A–D  are a sectional side view of the crimped region where the cover is folded over the flange; 
         FIGS. 6A and 6B  are a sectional side view of the crimped region where both the cover and flange are folded over and crimped; and 
         FIG. 7  is a sectional side view of the crimped region where the flange is folded over the cover and the flange and cover are crimped. 
     
    
    
     DETAILED DESCRIPTION 
     Referring now to  FIG. 1 , an assembly embodying the principles of the present invention is illustrated therein and designated at  10 . The assembly  10  includes a circuit board  12 , a metal housing  14 , and a cover  16 . 
     The cover  14  is disposed about the circuit board  12  to protect electronic components from the environment surrounding the assembly  10 . The cover  16  may include an electrical connector  17  with electrical contacts  18  that provide an electrical connection through the cover  16  to the printed circuit board  12 . The electrical connector  17  may be molded as part of the cover  16  to provide a robust seal therebetween. The metal housing  14  is attached to and seals with the cover  16  in a crimped region  20 . The metal housing  14  may be a deep drawn metal housing, as shown in  FIG. 1 , or alternatively, the metal housing  14  may be a seamed metal housing made of a rolled metal sheet, as shown in  FIG. 2 . If the metal housing  14  is made of the rolled metal sheet, the seam joining the two ends of the sheet may be welded or soldered. In addition, an anti-corrosive coating may be applied to the inner or outer surfaces of the deep drawn or rolled metal housing. 
     Now referring to  FIG. 3 , a sectional side view of the assembly  10  is provided. The circuit board  12  is attached to and extends from the cover  16 . The metal housing  14  is disposed about a portion of the circuit board  12  extending from the cover  16 . Electrical components  32  are mounted on a first surface of the circuit board  12  and a layer of thermal adhesive is disposed therebetween to secure the electrical components  32  and aid in dissipating heat generated by the electrical components  32 . A surface  30  of the metal housing  14  extends inwardly toward the circuit board  12 . The surface  30  provides additional surface area in close proximity to the component to aid in heat dissipation. In addition, the surface  30  may be configured to support the circuit board  12 . In the example shown, a thermal adhesive  34  is disposed between the surface  30  and the circuit board  12  allowing the surface  30  to mechanically support the circuit board  12  and also providing a more efficient thermal path between the electrical components  32  and the metal housing  14 . Although, a thermal adhesive  34  is shown disposed between the surface  30  of the metal housing  14 , the metal housing  14  may directly support the circuit board  12  or alternatively, other elastic materials may be disposed therebetween. 
     Now referring to  FIG. 4A , the crimped region  20  attaching the cover  16  and the metal housing  14  is provided in more detail. Extending from the metal housing  14  a flap  38  extends from the metal housing  14 . The cover  16  has a flange  36  extending from the cover  16  substantially parallel to the flap  38 . A crimped region  20  is formed by rolling the flap  38  together with the flange  36  such that a surface  40  of the flap  38  mates with a surface  42  of the flange  36 , thereby creating a seal and attaching the metal housing  14  to the cover  16  as shown in  FIG. 4B . Further, the flange  36  may be made of a conductive metal and crimped around the entire or substantially the entire perimeter of the metal housing  14 , thereby creating a continuous electromagnetic shield including the metal housing  14  and the cover  16 , around the circuit board  12 . For future repair of the circuit board  12 , the flap  38  and flange  36  may be unrolled or straightened allowing access to the circuit board  12 , then resealed with the old cover or a new cover by rerolling or recrimping the metal housing  14  to the cover  16 . 
     Now referring to  FIG. 5A , another embodiment of the crimped region  20  is provided in accordance with the present invention. The flap  38  may extend beyond the length of the flange  36  as shown in  FIG. 5A . The flap  38  may then be folded over the flange  36  as depicted in  FIG. 5B . As such, the sealed surface area between the flap  38  and the flange  36  increases over the previous rolled embodiment. A crimp  39  is introduced to both the flap  38  and the flange  36  such that a first surface  46  of the flap  38  mates with a first side  48  of the flange  36  and a second surface  52  of the flap  38  mates with a second side  50  of the flange  36 , thereby creating a seal and attaching the metal housing  14  to the cover  16 , as shown in  FIGS. 5C and 5D . 
     Now referring to  FIG. 6A , another embodiment of the crimped region  20  is provided. In this embodiment both the flap  38  and the flange  36  are folded over together and the crimp  39  is created in all four layers (two layers of the flange and two layers of the flap). The crimp  39  creates a controlled bend in the flap  38  and flange  36  such that, a first surface  54  of the flap  38  mates with a first surface  56  of the flange, a second surface  58  of the flange  36  mates with a third surface  60  of the flange  36 , a fourth surface  62  of the flange  36  mates with a second surface  64  of the flap  38 , thereby creating a seal and attaching the metal housing  14  to the connector cover  16 , as depicted in  FIG. 6B . 
     Now referring to  FIG. 7 , another embodiment of the crimped region  20  is provided. In the embodiment shown in  FIG. 7 , both the flange  36  and the flap  38  are folded at a 90° angle. The flap  38  and flange  36  may be folded to extend along the metal housing  14 , although it is contemplated that the flap  38  and flange  36  may also be folded to extend along the cover  16 . A crimp  39  is imparted to the flange  36  and flap  38 . The crimp  39  forms a mating surface  66  on the flap  38  and a mating surface  68  on the flange  36 , thereby forming a seal and attaching the metal housing  14  to the cover  16 . 
     As a person skilled in the art will readily appreciate, the above description is meant as an illustration of implementation of the principles this invention. This description is not intended to limit the scope or application of this invention in that the invention is susceptible to modification, variation and change, without departing from spirit of this invention, as defined in the following claims.