Fillet Rolling Strength And Numerical Simulation Of The Automotive Air Compressor Crankshaft

Automotive piston type air compressor as the main air brake pressure generating device,its quality determines the stability of the automotive brake directly. Crankshaft as one of the keycomponents of piston type compressor, bears huge cyclical load transmitted by connecting rodand inertia force caused by reciprocating and rotational movement in each of the compressorduty cycle. These alternating loads act on the entire crankshaft make it generate bending,torsion and complex alternating stresses, result in fatigue crack, especially at the transition filletof the crankshaft main journals and the rod diameter. The study showed that the fillet rollingtechnology was the most effective way to improve the crankshaft fatigue strength, it can notonly reduce the crankshaft surface roughness, improve the hardness, can also stitch feed marksand other surface defects which caused by cutting, so that stress concentration was reduced,productivity was enhanced and the final cost was reduced. Fillet rolling have no obvious effectsfor steel crankshaft, but for nodular graphite cast iron crankshaft, it can improve the crankstrength greatly, and the cost of nodular graphite cast iron crankshaft is only2/3comparing withsteel crankshaft. Therefore, considering the economical efficiency and reliability, it is a goodchoice to use nodular graphite cast iron crankshaft with fillet rolling instead of steel crankshaft.While the crankshaft rolling technologies and key equipments have been dominated by foreigncompanies, to study the key technologies on crankshaft fillet rolling and develop the relatedequipment have greatly significance in practical applications. This article has done thefollowing research on rolling process for strengthen air compressor crankshaft：(1) An analysis was made firstly on crankshaft fillet rolling mechanism and rolling processfrom the stress and damage situation of the air compressor crankshaft.(2) A modal of compressor crank manufactured by Dongfeng Pumps Co.Ltd was builtusing3D software (Pro/E) and virtual prototyping technology, and on the platform of ADAMSthe kinematics analysis was conducted, so kinetic characteristic of each part of compressorcrank-connecting rod mechanism, and forces exerted on crankshaft journal and crankpin wareobtained, the result can provide a reliable basis for follow-up crankshaft fatigue strengthanalysis.(3) A numerical simulation of the rolling process for crankshaft rolling model wasconducted in DEFORM software, so we can research stress and displacement in the rollingprocess of dangerous parts, and influence of the rolling parameters (number of rolling circle,rolling speed, roller radius)on residual stress.(4) Using UG(NX-NASTRAN) software, a finite element analysis of crankshaft modalwas conducted, so the stress and displacement situation of crank journal at loading conditionsware researched. It can be expected that the automotive air compressor will have very badly need，high-effect roll extrusion equipment can be designed and made in our country may bring aboutvery high economic value. What did in this thesis may provide the certain rationale for theentire rolling process optimization and research on rolling devices.