Process Analysis Of Cylinder Block Assembly Of Pre-assembly For WD618 Diesel Engine

WD618 Diesel is a new high-speed diesel engine manufactured by Weichai Power Company Limited. It is manufactured by the technology introduced from Co.STEYR (Austria). Some advanced technologies of 1990s are employed in manufacturing the engine. Type of its inline six-cylinder, water-cooled, four-stroke. The diesel engine on one of the key pieces of the overall size of the cylinder: Length 969 mm, 372.5 mm wide, 419 mm high and 260 Kg heavy rough, the average thickness 7 mm, Material for HT250, is a typical thin-walled, complex structures, and high-strength castings. WD618 series diesel engine in the WD615 series on the basis of the same use of advanced technology from abroad in China's high-speed diesel engines for heavy trucks, construction machinery, such as the use of generators. The machine has access to reliable, economic and technical indicators excellent, low emissions, starting fast, simple operation and easy maintenance, and other advantages. As a key process, the machining of crankshaft and camshaft bores in cylinder block is a choke point in producing for a long time. It is necessary to design a new combined machine tool, which can be used specially in boring the crankshaft bores and camshaft bores, in order to improve the boring precision and increase productivity. In this paper, the design of a high precision combined boring machine for cylinder block assembly (include cylinder block, crankcase, main bearing cover etc.) of model WD618 Diesel is introduced. There are five difficulties in designing: lack of rigidity in multi-layer walls manufacturing tool, low oriented precision of oriented system, too much vibration in machining process, low rigidity and movement precision of main axis parts and low movement precision of power moving parts. The designs of boring process, boring mould, boring bar, boring tool and precision boring head are analyzed and researched, and the five problems above are solved. A set of design method and some experiences are obtained by theoretically analyzing and practically designing, manufacturing and using of this boring machine. In the design, the adopting broaching process is employed instead of push boring, and the deformation of boring rod is reduced while the machining precision is ensured at the same time. The new combined boring machine tool has been used in production. It can meet or exceed the requirement of manufacturing WD618 Diesel cylinder block. The machine can meet the demand of mass production of WD618 Diesel. The design method is valuable for the designing of similar machine tools. Key Words: Diesel ,Cylinder Block Pre-assembly,Process Analysis...