Experimental Study On The Application Of Surface Coating Technology In Cam-tappet

Cam-tappet is one of the basic components of the engine valve mechanism, undertake according to the working cycle of the cylinder and ignition sequence requirements open or close of each cylinder, exhaust valve, to ensure that the engine scavenging process to achieve the best important task. Cam-tappet friction pair is one of three friction pairs of the engine, the complex condition and friction wear conditions in a large extent determines the service life of the engine. With engine power density increasing, the cam tappet friction pair in contact stress, lack of lubrication, strong vibration, etc. the complex conditions, the friction pair surface friction and wear problems has become an important task to ensure the service life of the engine.This paper to armored vehicles for the high power density of engine cam tappet friction vice as the research object, on the basis of analysis of the working principle of engine valve mechanism, focuses on the analysis of the cam tappet friction vice failure mechanism, on the working cycle of contact stress is analyzed in theory. Through the gas distribution mechanism of single mass dynamic model analysis, obtain the valve displacement, velocity and acceleration factors movement deformation considering gas distribution mechanism of elastic, quite column between the contact force and contact stress changes with the rotation angle of the cam of the cam is obtained. This is based on further for cam tappet friction pair tribological analysis, clearly improved the tribological properties of surface structure design elements.Attempts by surface coating technology to strengthen and improve cam-tappet friction pair surface tribological performance is the core content. Respectively take WC-12 Co coating preparation and Ni Cr-Cr₃C₂ coating preparation process of cam tappet friction pair specimen surface coating processing, in order to and solve the problem of friction pair surface wear resistance and antifriction. In accordance with the requirements of the "four factors three levels orthogonal experiment" made nine groups of specimens, to try to get the microstructure observation, material properties analysis based, confirmed the supersonic flame spraying method for preparing WC-12 Co wear-resistant coating, using laser cladding method of preparation Ni Cr-Cr₃C₂ reduced the effective application of the friction coatings. Further, the cam tappet analysis and simulation as the basis, of the cam tappet friction pair tribological experiments to test design, and the use of MRH-3 high speed ring block wear test machine of cam tappet wear process wear test. The contrast test of the coefficient of friction of the surface of the coating layer and non coating surface friction deputy of the actual conditions. Experiments show that the use of WC-12 Co preparation of wear resistant coating than the Ni Cr-Cr₃C₂ reduced friction coating technology produced by the friction surface of the specimen can effectively reduce friction coefficient, and enhance the wear resistance of the surface, and to improve cam tappet friction pair of service life to obvious application effect.