The analysis of puncheon periodic vibrations of the ultrasonic sewing machines

The article deals with the research of periodic vibrations of the sewing machine's puncheon for ultrasonic welding of materials. The dynamic model of the puncheon drive mechanism is analysed, taking into account elastic-dissipative characteristics of springs that are disposed between a puncheon holder and a machine casing, a puncheon holder and an output link of leverage mechanism of the drive mechanism. Welding materials are represented as an elastic-dissipative element and a unilateral constraint element. With the use of the periodized harmonic method, the analytical solution of the nonlinear differential equation of the mathematical model of puncheon vibrations was found. The proposed analytic dependencies can be used for the research of the system's amplitude-frequency characteristics and the selection of design requirements of the driving mechanism, taking into account the standard conditions of an ultrasonic sewing machine.