Stress–strain state of the valve spring in an auto engine during plastic hardening

Improvement of Method and Mechanism for Conical and Paraboloid Springs Hardening

“…The mechanism for contact hardening of conical and paraboloid springs is described by Patent RU 2686435 [9], thus containing the upper and lower liners, a cup to mount the liners in it and between them -to mount the tested spring and a punch with a spherical surface in contact with the spherical surface of the upper liner, while the lower liner is installed with the possibility of rotation about the axis of the cup, and the upper -with the possibility of rotation and movement along the axis of the cup and with the deviation of the axis from the axis of the punch; the upper liner is connected to the punch by means of a shoulder screw with the provision of gaps between the outer surface of the cylindrical part of the screw and the counter surface of the hole in the liner and between the screw head and the counter surface of the liner, while the inner working surface of the cup is made with the diameter equal to the diameter of the compressed conical or paraboloid spring and has a shape that covers the outer surface of the compressed conical or paraboloid spring, respectively, and the upper liner contacts the inner surface of the spring and has a conical shape or that of a paraboloid of revolution, respectively; in this case, the surface of the lower liner is made with an annular groove at the end with a diameter corresponding to the smallest inner diameter of the narrower side of the spring and a depth not less than the height of the spring coil, and the surface of the upper liner at the end has an annular groove corresponding to the largest inner diameter of the wider side of the spring and a depth not less than the height of the spring coil. The lower liner is connected to the lower press cylinder by means of a rod so that to displace the spring from the cup and to remove it from the lower liner.…”

“…The advantage of the proposed device in reference to the well-known one [9] is the ability to strengthen the inner surface of compression springs having a shape of a cone or a paraboloid of revolution in a compressed state, since the greatest effect of increasing the bearing capacity and performance of springs is achieved by strengthening the inner surface of the coils. In this case, the greatest stability is achieved by hardening the springs in a stressed state [7], which is ensured by the use of contact hardening.…”

The Nonlinear Dynamic Calculation of Deformed State of Various Types of Springs.

“…In this case, the some coils of the spring will constantly be subjected to maximum deformation, which will lead to critical fatigue of material. The some researches of stress-strain state of various types of the springs are presented in the works [5][6][7][8][9][10]. Predicted partial destruction of material can be determined by the results of the computer simulation of the spring deformation process in the dynamic mode.…”