To provide a vibration insulating device easy in initial design and having no risk of surging.
The vibration insulating device is provided by arranging a coil spring 13 and a steel ball 15 in a space S in a rubber spring 12 by interposing the cylindrical rubber spring 12 between flanges 11 and 11 fixed to a vibration restraining structure. When absorbing vibration by the expansion by the rubber spring and the coil spring, the respective steel balls repeat contact and microvibration between mutual ones by vibration caused by its expansion, and vibrational energy is dissipated as heat energy by its friction, and a damping effect is exhibited. At this time. the steel balls contact with both a coil spring surface and a rubber spring inner surface, and exhibit the damping effect even by its friction. Thus, a loss factor in a natural frequency of a system is increased by an element except for a spring element, and the resonance peak in the natural frequency of the system is also minimized. Since the coil spring is brought into a state of being embedded in a filling layer of the steel balls, a risk of the surging of the coil spring is reduced.
IIDA KAZUYOSHI
KAYANO HARUO
Higashio Masahiro
Takayoshi Tagawa