Studies On Processing Technology And Inner Milling Technology Of Crankshaft

With the fast development of automobile industry recently, the native demands of diesel engine and gasoline engine are rising constantly while the quality requirements are continuously heightened. Crankshaft which acts as a power-transfer medium is the key component of diesel engine and gasoline engine and it endures complexity alternating load. The main failure mode is the fatigue fracture in fillets. The quality of crankshaft directly affects the dynamic performance and the service life of engine.The inner milling of crankshaft as an advanced technology is not only applied to the rough machining of the main journal and rod journal, but also used in the machining of the milling fillets and the crank arm side. The inner milling, which is used to forge steel crankshaft in automobile engine, has been adapted to the domestic crankshaft blank production status and used by many engine factories, because of its easy broken chip, large machining redundancy and low requirement of quality roughcast.Along with the development of the computer technology the finite element method (FEM) has been widely applied in many engineering fields. It has also been applied to the designing and developing of automobile engine accessory. FEM brings a lot of convenience to the designers,because it improves the reliability of accessory and shortens the design cycle.This article analyses the processing technology of crankshaft ZJ25, especially the working procedures of drilling the central hole, grinding and strengthening. Some problems in processing have been found out and an evaluation for processing technical level has been made.This article also emphatically studies the technology of the inner milling of crankshaft. By means of comparing the inner milling processing with the other rough machining processing for the crankshaft journal, the inner milling machining principle and machining equipment are studied. Through the force analysis of fillets and rod journal, the stress concentration problem of the journal fillets after the inner milling are found out.Three kinds of fillets with different shape or size for the rod journal of ZJ25 crankshaft have been designed. It establishes three kinds of geometric models for the rod journal, meshing and defining the boundary conditions and applying stress, and solving with the ANSYS software. By analyzing the results, a fillets design scheme with the most suitable inner milling processing technology and the less maximum stress is obtained. It increases the processing quality of inner milling and improves the stress concentration of fillets.