Tubular oil filter comprising two pressure injection molded plastic shells is provided with metal-bushed bolt holes during hot pressure welding of shells, which remain proud following fixation

摘要

The filter unit main body (1) is largely tubular with a filter inside. Flanges (3) of the unit are fastened with bolts, their holes (4, 5) passing through the body. An independent claim is included for the corresponding method of making an oil filter by pressure injection molding of the shells. The filter is then fastened inside one of them. Bonding surfaces of the shells are then heated and melted, bringing them together, forming the tubular body. The metal tubes are press-fitted into the bolt holes. The filter body is pressed to fasten it onto the guide tubes, leaving guide tube ends projecting. Preferred features: Metal guide tubes are inserted and fastened in the bores (4, 5) of the flange region, to guide and support the bolts.