JPS6440734A - Vibration preventive device - Google Patents

Abstract

PURPOSE:To enhance the durability by providing elastic wall parts facing a plurality of small liquid chambers, which are expanded and contracted with displacement between an inner and an outer cylinder and put in communication through a restriction passage, bending these elastic wall parts in the direction of expansion and contraction of the small liquid chambers, and thereby preventing generation of great defoliating force. CONSTITUTION:An inner cylinder 30 and an outer cylinder 32 are arranged coaxially, and an intermediate cylinder 34 is fixed inside this outer cylinder 32 through an elastic member with small wall thickness 36. Between this and the inner cylinder 30 a cylindrical elastic member 38 is set over, and small liquid chambers 40, 42 are filled with the liquid and in communication with the periphery of the intermediate cylinder 34 through a ring-shaped recess. The periphery of this recess is shut by the outer cylinder 32 to become a restriction passage 44, and serves as a moving path when either of the small liquid chambers 40, 42 has an increased pressure. A stopper 46 protruding to the small liquid chambers 40, 42 is fixed at the periphery of the inner cylinder 30 covered with a small wall thickness part as extension of the above-mentioned elastic member 38, to perform restriction of the amount of motion when the inner 30 and outer 32 cylinders make relative movement. Thus no major stresses are concentrated on the elastic members constituting liquid chamber even at the time of relative movement between the inner and outer cylinders to ensure that the elastic members are installed certainly and the durability enhanced.