Abstract: A process for producing hermetically sealed filters is disclosed. The process includes the steps of providing thermoplastic base and top filter parts and a section of filtration media, sandwiching the media between sections of the base and top filter parts under a compressive force, applying a rapidly repetitive force to at least one of the filter parts to cause movement between the parts and frictional welding of the parts, maintaining the compressive force after frictional welding to allow the melted portion of the parts to solidify and thereby form a fluid seal at the junction of the filter parts and at the junctions of the filtration media and each of the base and top filter parts. In one embodiment, the junction between the filter parts is the periphery of an automatic transmission filter, and the junction is hermetically sealed. A hermetically sealed automatic transmission filter is also disclosed.

Abstract: An automatic transmission fluid filter is disclosed, comprised of a metal base member, a plastic cover member attached to the base member, enclosing a volume. Filtration material inside the volume is interposed between an inlet and outlet to the filter. A plastic overmold around the periphery of the union of the metal and plastic members hermetically seals the filter except at the inlet and outlet. In a preferred embodiment, the metal base member includes a flanged edge which is secured to a flanged edge of the cover member by the overmold. Slots through the flange of the base member allow plastic of the overmold to flow through, connecting together plastic on both sides of the flange. Also, the base member flange ends curled lip embedded in the plastic of the overmold. Edge sections of the filtration material extend to and between the union of the base and cover members over some sections of the edge of the filter.

Abstract: A filter suitable for press fitting into an assembly for inline filtration is disclosed. The filter includes a base, filtration material supported on the base, and a metal collar surrounding at least a portion of the base with a portion of the metal collar embedded in the base. The leading edge of the collar and anchor tabs on the distal end of the collar are embedded in the base and thus secure the collar to the base. The collar also has a rounded entry corner which provides a smooth entry into the press fit hole when the filter is pressed into place.