KNURLED EYELET ASSEMBLY
Original Publication Date: 1984-Apr-01
Included in the Prior Art Database: 2001-Oct-15
An outward-flared end of a brass eyelet is used to hold an aluminum heatsink baseplate to a plastic housing of an electrical module. Inside the plastic housing an electrical subassembly will be mounted on a ceramic substrate that will be soldered to a copper surface of the aluminum heatsink baseplate of the module. A mounting screw will extend through the brass eyelet and mount the module to a main heatsink with the outside surface of the aluminum heatsink baseplate being in direct contact with this main heatsink. The drawings illustrate the tools utilized in the present invention to perform the outward flaring of the brass eyelet so that the aluminum heatsink baseplate is held to the plastic housing of the module. The aluminum baseplate has a ceramic substrate soldered to a copper portion of an inside surface of the baseplate such that the housing, the baseplate, the eyelet, and the ceramic substrate and its electrical components together form an electrical module. In particular, it is contemplated that this module can be a voltage regulator module for automotive applications. After the assembly of the aluminum baseplate and ceramic substrate to the plastic housing via the brass eyelet, the interior cavity of the housing is filled with a silica jell potting compound to protect the electrical components. This potting compound is typically not strong enough to reliably join the aluminum baseplate to the walls of the plastic housing such that the main function of the flared eyelet is to accomplish the mechanical bonding of the aluminum baseplate to the plastic housing. An important feature is that no soldering of the eyelet to the aluminum baseplate is required, but yet electrical connection between the eyelet and baseplate is still provided by the present technique. Also, the present technique does not require the knurled flared end of the eyelet to extend beyond the outer surface of the aluminum baseplate, thus readily permitting an intimate contact of the outside surface of the baseplate to the surface of the main heatsink to which the module will be attached.