Research On Spinning Forming For Shell Of Silicone-oil Damper On Automotive

Spinning,as a typical continuous plastic forming technique,has become an important development direction due to its advantages of hydrostatic forming(no impact,vibration and environmental hazards),high product precision,good process flexibility,easy mechanization and automation,material saving,which is an advanced manufacturing technology to achieve thin-walled rotational parts with cutting less.The shell of damper is a kind of double cylinder parts with flange.Compared with the traditional method such as forging,casting and welding,the whole spinning process greatly reduces the working procedure,and with good adaptability of process,high utilization of material.In the forming,the flow line of material is integrity,the direction of fiber organization is reasonable distribution,and with uniform forming,good balance of static and dynamic.The final surface of part with cold hardened layer and the strength is improved.Relying on “The research and industrialization of key technologies of ‘Light weight-High precision-Net forming' in automobile poly-wedge hub” in Jiangsu Province(BA2016047),and based on the analysis of the development and research status of pulleys/shell spinning in domestic and foreign.The article taking shell of silicone-oil damper as the research object,the spinning process of the double cylindrical pulley/shell was studied.For the analysis of spinning process of the double-cylindrical pulley/shell,the deformation process is divided into three stages:thickening of shovel spinning,spinning flange,and tooth spinning(or machining).Based on the software platform of Simufact,the finite element model which conforms to the actual technology of double cylindrical parts was established,the metal flow and process parameters of shovel spinning and spinning flanging was analyzed.Which to reveal the mechanism of forming and obtained a common spinning process of double cylindrical partsThe material in the deformation zone has the displacement toward the axial,radial and tangential directions due to the compressive stress with unuiform distribution during shovel spinning processing.With the decrease of the radius of the inner cylinder,the material of the tangential gradually moves along the axis and radial directions and therefore the inner cylinder exhibits an effect of increase in the axial length and the radial thickness.Fewer material concentrates at the bottom of the innercylinder during shovel spinning processing at the later stage of forming,and the metal at the bottom is easier to subjected to the compressive stress from the metal in the weakly deformed zone,which results to the difficulty of radial thickness and the formation of an inner groove at the fillet on the inside of the barrel wall.The greater the distance is,the more obvious the thickening effect and the lack of material is.It is easy to make some problems like lack of material on the top for the outer cylinder formed by conventional spinning flanging,due to the thinning of transition zone of the outer cylinder.For the processing of expand-spinning flanging,some other problems may occurred including burr and flashing in the transition zone of the outer cylinder,larger forming load for the effect of thickening.It can be controlled by regulating feed mode and initial position of the spinning wheel,so as to ensure the uniform distribution of the material and improve the film condition,to avoid the occurrence of forming defects.Through the numerical simulation,kinds of forming defects were forecasted and analyzed,The spinning experiment of shovel spinning and spinning flanging were tested on the spinning machine of CDC-60,and the results show that the effective height and the effective thickness can reach to 35 mm and 6.9mm,which are over 15 times and 3 times of the thickness of the shovel spinning respectively.For conventional spinning flanging and expand-spinning flanging,after repeated adjustment of the feed mode,the qualified outer cylinder were obtained.Both of them are suitable for the forming of the outer cylinder,in which the thickening effect of the expand-spinning is more adaptable to the part structure.The corresponding solution was put forward for the analysis of the defects and the quality evaluation during the spinning process,the qualified pulley are obtained and the forming is stable and reliable.The research results promote the application of finite element numerical simulation technology in the field of pulley spinning forming,enrich the theory of pulley spinning forming,which has a certain guiding significance and application value on the pulley.