Design And Research Of High-precision Combined Boring Machine For Machining Crankshaft And Camshaft Bores In Cylinder Block

X6170Z Diesel is a new medium-speed diesel engine manufactured by Weifang Diesel Engine Works. It is manufactured by the technology introduced from Co.MAN (Germany). Some advanced technologies of 1990s are employed in manufacturing the engine. 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 X6170Z 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 X6170Z Diesel cylinder block. The machine can meet the demand of mass production of X6170Z Diesel. The design method is valuable for the designing of similar machine tools.