Research On Mechanical Properties Of Equidistant Circular Arc Connection

With the rapid development of modern machinery industry,people’s requirements for mechanical transmission are constantly improving,especially in the service life,connection strength and overall structure of the connection part of the transmission system.The traditional mechanical transmission shaft and hub are mostly connected by keys.There is a sudden change in the shape of the structure,and the existing concentrated stress greatly weakens the connection strength.The contour curve of the equidistant circular arc surface shaft and the hub inner hole is a continuous smooth circular arc curve,without stress concentration points.This obvious advantage is that the traditional key connection can not be realized by optimizing the structure,The popularization and application of equidistant circular arc surface connection will improve the overall performance of mechanical transmission system.This paper analyzes and discusses the parameters that affect the shape of the contour curve of the equidistant circular arc,carries out static calculation of the axis of the equidistant circular arc surface,and studies the changing law of the contact stress and torsional deformation of the equidistant circular arc surface connection under different connection parameters by using the finite element method.The main research contents and conclusions are as follows:(1)This paper analyzes the working principle of equidistant circular arc surface connection,derives the calculation formulas of polar moment of inertia,maximum shear stress on the shaft and contact pressure during connection of equidistant circular arc surface shaft section,and obtains the expression of its torsional stiffness through the torsional model of profile shaft.(2)According to the mathematical model of equidistant circular arc profile curve and UG modeling,it is found that when the nominal diameter is fixed,the more arcs the more complex the profile curve is;The smaller the eccentricity is,the closer the profile curve is to the circle,and the greater the eccentricity can be used for the three arc profile curve.(3)By changing the eccentric distance,torque,friction coefficient of connection surface,fit clearance,connection length,hub wall thickness and other parameters,the variation law of contact stress of three kinds of equidistant circular arc connection is analyzed,and it is found that the contact stress is periodically distributed along the profile curve;The smaller the eccentricity,the greater the torque,and the smaller the connection length,the greater the contact stress;The existence of friction force makes the contact stress decrease greatly;The wall thickness of the hub has little influence on the contact stress;The influence of fit clearance on contact stress is complex;When the nominal diameter is the same,the contact stress of the three arc connection is smaller and the bearing capacity is stronger.(4)In the range of elastic deformation,there is a positive correlation between the stress and strain of the joint surface and the contact stress;The greater the eccentricity,the smaller the torsional deformation of the shaft and the hub;Increasing the wall thickness of the hub reduces the torsional deformation of the hub;When the interference fit is used,the torsional deformation is minimum and the torsional stiffness of the connection system is large;With the same nominal diameter,the torsion deformation of the five arc segment equidistant circular arc surface connection is the minimum.Through the above research,it is of great significance to improve the overall performance of mechanical transmission system and provide theoretical reference for the popularization and application of equidistant circular arc surface connection.