Dynamics of Starting of Vibrating Machines with Unbalanced Vibroexciters on Solid Body with Flat Vibrations

Abstract

Expressions for vibration moments (additional dynamic loading caused by the vibrations of bearing body) during the passage of resonant zone by vibration machines with the flat vibrations of bearing body both with one arbitrarily located vibration exciter and with two self-synchronization vibration exciters for the different modes of starting are got in an analytical form. Possibilities of improvement of process of running approach of vibration machines with unbalanced vibration exciters are demonstrated by using of methods of the "double" (in case of one vibration exciter) and "separate" starting of electric motors (in case of two vibration exciters). It is shown that the first method is based on using of semislow vibrations arising in the resonant zone. The necessary condition of the successful using of this method is motion on the rotor of exciter in the moment of the repeated including of engine of rotary-type vibration moment. The conditions when the separate starting is effective are shown. Conclusions and practical recommendations that allow to facilitate starting of vibration machines with an unbalanced drive are pointed.

Equations of motion of vibration machines with a translational motion of platforms and a vibration exciter in the form of a passive auto-balancer

“…The new technique is based on the same Sommerfeld effect as the techniques in papers [5][6][7]. Only, instead of a low-power motor, one uses small forces of viscous resistance to the relative motion of loads.…”

“…The disadvantage of the given method is the low efficiency coefficient of the system «compressed air -wind wheel -platform». Paper [7] describes a technique in which pendulums are mounted on the low-power electric motors' shafts. The pendulums' motion is synchronized over time and they get stuck at the resonance frequency of platform oscillations.…”

“…The simplest and most reliable ways to excite the resonance oscillations of platforms and rotors are based on the Sommerfeld effect [4][5][6][7][8][9][10][11][12][13][14][15][16]. One of these techniques is based on using a ball, a roller, or a pendulum auto-balancer in the form of a vibration exciter [8,11,12].…”

Studying the load jam modes within the framework of a flat model of the rotor with an auto­balancer

“…[1][2][3][4][5][6][7][8][9][10][11][12][13], are used for balancing high-rotational rotors at operation. The same devices with a single or more loads can be used in vibration machines in order to excite vibrations [14][15][16][17][18].…”

“…-load jams (caused by the Sommerfeld effect) [5][6][7][8][9][10][11][12][13][14][15][16]; -parametric and other oscillations of loads [17,18].…”