Designs And Researches Of A Muti-Functional Cam Transmission Test Rig

Cam mechanism is widely used in automatic machinery, apparatus and mechatronics control equipment. Specifically in the valve train system of motor engines, cam transmission is superior to control motion precisely. However, the cam-follower is a typical high-pair contact and easy to be worn. Thus the quality of lubricating conditions directly affects the service life of cam mechanism. Friction and lubrication fields have made great progress, which confirmed that the lubrication of cam-follower is a complex transient elastic hydrodynamic lubrication (EHL) in theory and many numerical calculates of lubricant film thickness for real cams have been made, but the observation and measurement of film thickness via tests are few. This thesis mainly aims at designing and establishing a multi-functional cam transmission test rig to deeply study key technic issues of measuring cam’s lubricant film thickness.With the theory of elastic hydrodynamic lubrication, the lubricating film of cam-follower was helpfully discussed. Compared some mature test methods of film thickness, analyzed advantages and disadvantages of existing cam lubricating film thickness test equipment using optical-interferometry. By analyzing the measurement principle of optical-interferometry and cam-follower’s motion characteristics, a novel test rig was designed, which could detect cam’s profile law and observe cam EHL film. Further more, the strength of test rig camshaft and glass disc were checked. A virtual prototype was established in ADAMS for kinematics simulation. The results have shown that this test rig runs stably. According to LAGRANGIAN solving method, the dynamic model of the test rig was build up. Thus, the non-linear dynamic equation was solved via finite element method. How different spring stiffness and motor speed effect lubrication entrainment speed and contact force was also probed to provide a reference for spring preload force selection and motor speed adjustment in cam elastic hydrodynamic lubrication tests.