Load acting on concrete crusher is actually the inertia force and inertia moment generated by movable vertebrae and vibrator, which is a cyclical dynamic load, therefore, it is inevitable to cause crusher vibration. Vibration forms of concrete crusher are vertical circular vibration, horizontal vibration, pendulum vibration, as well as extraneous vibration which is caused by intense shock and vibration, among which, horizontal circular vibration is principal oscillation, and other vibration forms are relatively small, so we here mainly talk about vibration isolation system of horizontal circular vibration.
Body of concrete crusher is located on the isolation system; if set shear elastic stiffness of vibration isolation system as K, total mass of material in concrete crushing machine as M, inertial force of concrete crusher in any horizontal direction as Fc, then the spring mass system of concrete crushing machine can be shown in the figure below.
If ignore damping, vibration of crushers in x direction can be calculated by:
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The first part is self-vibration of inherent frequency Wn, AA is free vibration amplitude, A2 is initial phase of crushing motion. The second part is the forced vibration of inertial force w. As damping always exist in actual vibration system, so with time going on, free vibration part of the primary crusher will decay. If Wn=w, the amplitude will be infinitely great, this phenomenon is known as resonance. When choosing vibration isolation system, inherent frequency Wn must be away from the inertia force frequency w, to avoid resonance. As shear elastic stiffness of rubber spring is smaller and affordable to multi-direction loads with large damp, it has good effect on absorbing shock and high frequency vibration and reducing noise, therefore, it is ideal to adopt rubber spring as vibration element of concrete crushing machine.