VARIABLE DAMPING FORCE DAMPER

摘要

Provided is a solenoid-type variable damping force damper that improves the strength of the piston and prevents wire break in the electromagnetic coil. A piston includes a piston main body, an expansion-side valve plate, a contraction-side valve plate, an electromagnetic coil, and a bolt. The piston main body is an integrally formed component made of a ferromagnetic material, and includes a hollow cylindrical outer yoke that is in slidable contact with an inner peripheral surface of a cylinder, a columnar inner yoke having an outer peripheral surface opposing an inner peripheral surface of the outer yoke via first and second gaps, and a connection member connecting the outer yoke and the inner yoke with each other at an axially middle position of the piston and separating the first and second gaps from each other. The electromagnetic coil is fitted in the second gap of the piston main body.

主权项

1. A variable damping force damper comprising:
a hollow cylinder containing hydraulic oil sealed therein; a columnar piston configured to reciprocate in the cylinder and separate an interior of the cylinder into a rod-side oil chamber and a piston-side oil chamber; and a piston rod having the piston at an end thereof, wherein the piston comprises: an inner yoke made of a ferromagnetic material, the inner yoke being secured to the piston rod and having an outer peripheral surface coaxial with the cylinder; an outer yoke made of a ferromagnetic material, the outer yoke having an inner peripheral surface coaxial with the outer peripheral surface of the inner yoke and opposing the outer peripheral surface of the inner yoke via a predetermined gap; an electromagnetic coil disposed in the gap; a communication oil passage having an opening in at least one of axial ends and connecting the rod-side oil chamber and the piston-side oil chamber with each other; and a valve plate configured to have elasticity and close the opening of the communication oil passage, the valve plate being made of a ferromagnetic material and attracted in a closing direction by a magnetic force of the electromagnetic coil, wherein the inner yoke and the outer yoke are connected with each other by a metallic connection member at a position different from that of the electromagnetic coil in an axial direction, and wherein an amount of magnetic flux flowing through the metallic connection member is smaller than an amount of magnetic flux flowing through the valve plate.