Study On Lubrication Characteristics Of A New Type Of Sliding Universal Coupling

With the development of technology and industry,the application of various couplings is more and more extensive,it has gradually become an indispensable transmission parts.The coupling is very simple and compact in structure,convenient in manufacturing,and it’s transmission performance is good,the universal coupling makes it possible to transmit the motion and torque between the intersecting shafts.On the basis of inheriting all the advantages of the universal coupling,sliding universal coupling also has the characteristics of transmitting large torque.Based on the motion analysis and force analysis of the various components(input shaft,output shaft,tripod,slider and joint bearing)of tripod sliding universal coupling,the kinematic and dynamic equations of each component of the coupling are obtained,which lays a theoretical foundation for further research.At the same time,according to the research and analysis of the friction and wear parts which are easy to produce in the working process of universal coupling,a new type of sliding universal coupling is proposed which is beneficial to lubrication,and the lubrication characteristics are studied theoretically.Firstly,in the process of kinematic analysis of the coupling,the motion coordinate system and the fixed coordinate system are established on the part of the coupling,the relationship between them is established by the transformation of the direction cosine matrix,and then the relative relation of each component of the coupling is obtained,which shows that the motion characteristics of the coupling are analyzed.In the dynamic analysis of the coupling,according to the inverse problem analysis method of mechanical dynamics theory,using the kinematic equation obtained before,the force and moment of each component are obtained,then the balance equation can beobtained,and the dynamic characteristics of the coupling can be obtained by solving the equation.Secondly,by analyzing the relative motion between the slider and the guide groove,it is understood that the contact surface between them is the main part of the friction and wear,and a new type of sliding universal coupling is proposed.Finally,the lubrication characteristics of the proposed new structure when using lubricating oil and grease are analyzed and calculated.In the analysis of lubrication characteristics when using lubricanting oil and grease,the basic lubrication of the new structure under isothermal elastohydrodynamic lubrication and the influence of various parameter variables on the lubrication are studied.Then the basic lubrication of the new structure under thermal elastohydrodynamic lubrication and the influence of various parameter variables on the lubrication are studied.By analyzing the results of isothermal elastohydrodynamic lubrication and thermoelastic elastohydrodynamic lubrication,in the direction of the length of the contact surface,the film thickness from the inlet area to the outlet area is gradually reduced,and a necking phenomenon appears.In the width direction,the film thickness in the vicinity of the center is larger than the film thickness of both sides.The pressure is mainly distributed in the center of the width,the length of the posterior,in the length direction,a secondary pressure peak appears near the outlet area.The parameters such as the frequency,viscosity,angle of the two shafts,the radius,the viscosity coefficient,the elastic modulus,the load increase,the viscosity coefficient and so on have different effects on the film thickness,pressure and temperature.