Process for manufacturing inner and outer parts for a rotary piston

Abstract

To manufacture inner and outer parts for a rotary piston machine in which said parts have parallel axes and have interengaging helical engaging surfaces having convolutions in numbers differing by one and are operable to perform relative to each other rotating and eccentric revolving movements, the helical engaging surface of at least one of said parts is machined by a cutting tool, which is rotated about an axis which is parallel to and spaced from the axis of the part that is to be machined. To permit an economical machining of said helical engaging surfaces and to achieve a very good surface finish on said engaging surfaces, a tool which is provided with teeth on an end face and on its peripheral surface is used to machine the helical engaging surface of the one part and those teeth which are provided on the peripheral surface of said tool conform as regards their arrangement and the design of their cutting edges to the profile of the helical engaging surface of the other part, that the tool and said one part are subjected to a feed movement relative to each other, which feed movement is composed of a basic feed movement, which corresponds to the relative operating movement of the inner and outer parts, and of a superposed movement, which corresponds to the desired helical shape of the engaging surface to be machined.