GB954773A - Improvements relating to the assembly and disassembly of parts having an interference fit between them - Google Patents

Abstract

954,773. Assembling force fits. SULZER FRERES S.A. March 21, 1963 [May 18, 1962], No. 11339/63. Heading B3U. A method of assembling a cylindrically bored part on to a cylindrical member with an interference fit using an auxiliary conical element extending from and axially aligned with one end of the member, the element diameter adjacent the member being equal to that of the member comprises, sliding the part on to the smaller end of the element, applying pressurized fluid to at least one passage in the part which opens on to the bore surface, moving the part along the element and on to the member and releasing the pressure. The parts may be removed by carrying out the reverse procedure. A conical element extension 10, having a taper 1: 1250 is connected e.g. by screwing to one end of a camshaft 1 and parts 2 e.g. cams, gears having internal annular recesses and fluid connections 6 are positioned thereon, pressurized fluid e.g. oil is supplied via the connections to expand the parts which are successively slid along and positioned on the camshaft at which point the pressure is released and the connections removed. A resilient or plastic spacer member 11 or a cylindrical spacer having a diameter equal to that of the cam-shaft 1 may be positioned between the element 10 and cam-shaft. Alternatively the cam-shaft may be produced with an integral conical extension to facilitate assembly. The element may have a constant or variable taper. In a modification an externally conical hollow element 20 is secured to the end of the cam-shaft, a part 2 is slid on to the cone which is expanded by the hydraulic pressure admitted via a connection 24 into the cavity 22 until its external diameter is equal to that of the front end of the element and the cam-shaft, the part 2 is then expanded as before and slid on to the shaft. Alternatively the element is expanded by filling the cavity 22 with a plastic composition or a number of small balls which are compressed, or by making the cavity conical and inserting a tapered member therein or by heating via a heating coil inserted therein. Screw-on or hydraulic means may be applied to move the parts on to the shaft. Dis-assembly is achieved by reversing the process. The method may be used to assemble cams on to heavy diesel engine cam-shafts.