公开(公告)号：US20220316547A1

公开(公告)日：2022-10-06

申请号：US17615928

申请日：2020-05-26

Applicant: Hitachi Astemo, Ltd.

Inventor： Tomohiko IIDA ,  Kosuke KADOKURA ,  Kento MONJI ,  Shunsuke MORI

IPC: F16F9/46 ,  F16F9/18 ,  F16F9/34

Abstract: When a damping force adjustable shock absorber operates in a soft mode, a piston is performing a compression stroke, and a piston speed falls within an ultra low speed range, communication between an upper cylinder chamber and a reservoir is interrupted by an ultra low speed valve provided in a pilot passage. The interruption of communication enables expansion of an oil liquid in the upper cylinder chamber when the piston is performing the compression stroke and the piston speed falls within the ultra low speed range. A differential pressure is generated between an upper cylinder chamber side and a lower cylinder chamber side of a compression-side ultra low speed valve. As a result, when the piston speed falls within the ultra low speed range, the compression-side ultra low speed valve is opened, and a damping force having a valve characteristic achieved by the ultra low speed valve can be generated.