Patent ID: 6588554
Filing Date: 2003-07-08
Classification: F16F

Abstract:
A vibration damping apparatus using a magnetic circuit, comprising:a movable member disposed relatively movable along an axial direction in respect to a casing; a movable magnet fixed on said movable member; a stationary magnet fixedly disposed in said casing, and forming a magnetic field to have a negative spring constant in a predetermined range of the displacement amount in the axial direction of said movable member with said movable magnet; an elastic member to force said movable member in a direction to keep a distance away from the bottom wall of said casing, and to set a spring constant obtained by combining a magnetic force of a magnetic field formed by said movable magnet and said stationary magnet and an elastic force, to be substantially zero in a predetermined range of the displacement amount in the axial direction; and a piston which moves by being pressed with said movable member and presses a viscous liquid filled in said casing to create fluid resistance when the displacement amount of said movable member in the axial direction reaches a predetermined value.