Research On The Pulsating Hydraulic Connection Strength Of Assembled Camshaft

Assembled camshaft manufacturing technology is a novel manufacturing technology that assembles separately processed parts into a camshaft.Compared with the traditional integrated camshaft manufacturing technology,the assembled camshaft manufacturing technology has unique advantages in reducing production costs and diversified product design.Assembled camshafts bear torsional loads during service.Therefore,the research on the connection strength of assembled camshafts is extremely important.The pulsating hydroforming technology can improve the forming performance of the material,make the pipe have a better bulging amount,and make the mandrel have better filling performance.Therefore,studying the connection strength of assembled camshafts under pulsating hydraulic connection technology is of great significance for improving the connection strength of camshafts.(1)Perform a pulsating hydraulic connection test for the new connection structure to obtain a assembled camshaft test piece;then perform a filling test on the test piece to obtain the filling performance of the mandrel under different pulsation(frequency or amplitude)parameters,the influence of parameters on filling performance is obtained(2)Obtaining the constitutive relationship of materials is used to import finite element software for simulation.Perform pulsating hydraulic connection simulation of assembled camshafts with different pulsation parameters(frequency or amplitude),and obtain data on the contact area between the mandrel and the cam connecting surface.The influence of amplitude and pulsation frequency on the contact area of the interface is obtained.Analyze the relationship between the filling performance of the mandrel and the contact area,and finally verify the simulation accuracy(3)Carry out simulation and experiments on the service life of the assembled camshaft to obtain the connection strength of the camshaft test piece.The influence of pulsation amplitude and pulsation frequency on the connection strength of assembled camshafts was obtained.The relationship between the connection strength and the contact area and the filling performance of the mandrel was analyzed.The research results show that:(1)During the connection process,because the gap amount between the outer wall of the mandrel and the cam inner hole profile changes periodically in the circumferential direction before the connection,the minimum gap amount is in the middle of the flat portion,and the maximum gap amount is in the protruding portion.In the process of increasing the hydraulic pressure,the mandrel first contacts the flat part of the cam inner hole profile,and then contacts the protruding part.After the pressure is released,the contact area of the flat contact part decreases sharply,and the reduced contact area of the protruding part is relatively flat.(2)The increase of hydraulic pressure will increase the filling rate of the mandrel,and at the same time the filling rate of the mandrel will increase with the increase of the pulsation parameter,but the increase of the hydraulic pressure has a suppressing effect on the influence of the pulsation parameter on the filling rate.(3)Reasonable selection of loading pressure and pulsation parameters can greatly increase the contact area of the connection surface,but choosing a larger hydraulic pressure will reduce the impact of pulsation parameters on the contact area.The effect of the filling rate on the residual contact area increases with its own value.(4)Higher connection strength can be achieved by using higher loading fluid pressure and pulsation parameters;meanwhile,the filling rate of the mandrel has a certain effect on the connection strength.Increasing the filling rate of the mandrel will also increase the connection strength;the contact area will also affect Connection strength.Increasing the contact area will result in higher connection strength.