Hitachi Automotive Systems, Ltd.

Hitachi Astemo Ltd.

Mikio Yamashita

Fumiyuki Yamaoka

Atsushi Maeda

Masaru Kouyama

Shunsuke Mori

Takamasa Kotani

Ryo Shinata

Kunio Takiguchi

Makoto Nishimura

Takao Nakadate

Yohei Katayama

Kosuke Kadokura

Kazuya Matsuda

Kentaro Yamada

Kenji Noda

Naofumi Harada

Daisuke Tanabe

Kengo Hase

Reiji Nakagawa

Daiki Miyazawa

Toru Hosokawa

Atsufumi Ishimoto

This shock absorber has a first damping force characteristic that is exhibited when a piston speed is from a low-speed region to a high-speed region while a relative position of a piston with respect to a cylinder is in a first range during a low frequency, a second damping force characteristic greater than the first damping force characteristic is exhibited when the piston speed is from the low-speed region to the high-speed region while the relative position is in a second range different from the first range during a low frequency, and a difference in damping force characteristic between during the first range and during the second range is smaller than a difference between the first damping force characteristic and the second damping force characteristic during a high frequency. A second passage is provided with a variable orifice mechanism with a changeable orifice area based on relative position.

Shock absorber

This shock absorber includes a first damping force generation mechanism () provided in a passage () of a piston (), a second damping force generation mechanism () provided in a piston rod (), and a fluid storage mechanism () provided in the piston rod (). The fluid storage mechanism () includes a flexible disc () which deforms before the second damping force generation mechanism () opens, and a plate-shaped biasing member () which has a hole portion () between an inner circumferential end portion and an outer circumferential end portion, and in which the inner circumferential end portion is formed so that the piston rod () can be inserted therein.

This shock absorber includes a first damping force generation mechanism provided in a passage of a piston, and a second damping force generation mechanism provided in a piston rod. The second damping force generation mechanism includes a valve seat member, a sub-valve provided in the valve seat member, and a cap member covering one end side of the second damping force generation mechanism and at least a part of an outer circumference of the valve seat member. A communication passage is formed on one end side of the cap member. A biasing member provided so that one end surface side is in contact with an outer circumferential side of the cap member with respect to the communication passage, and a bendable flexible disc provided so that the other end surface side of the biasing member is in contact therewith.

A damping force adjustable shock absorber including a compression-side ultra low speed valve that allows passage of an oil liquid from a lower cylinder chamber to an upper cylinder chamber. The compression-side ultra low speed valve is provided in a third passage and arranged in parallel to an extension-side ultra low speed valve. Thus, when a piston is performing a compression stroke and a piston speed falls within an ultra low speed range, oil liquid in the upper cylinder chamber can be expanded, resulting in a differential pressure between the upper cylinder chamber side and the lower cylinder chamber side of the compression-side ultra low speed valve (fifth 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, enabling generation of a damping force having a valve characteristic achieved by the ultra low speed valve.

Damping force adjustable shock absorber

A damping force adjustable shock absorber includes a flow path (an oil passage of a piston) in which a flow of hydraulic fluid is generated due to a movement of a piston rod, and a damping force adjustment valve provided in the flow path and configured to be subjected to an adjustment of an opening/closing operation by a solenoid. A frequency adaptive mechanism is provided in the flow path in series with the damping force adjustment valve. The frequency adaptive mechanism is configured to reduce a damping force for a high-frequency vibration. The frequency adaptive mechanism includes a second valve mechanism (a compression-side damping force generation valve and an extension-side damping force generation valve) configured to apply a resistance force to a flow of the hydraulic fluid from an upstream-side chamber (an upper-portion chamber or a lower-portion chamber) to a downstream-side chamber (the lower-portion chamber or the upper-portion chamber).

A first damping force generation mechanism provided in a first passage formed in a piston to generate a damping force, and a second damping force generation mechanism provided in an annular valve seat member disposed in one of chambers and provided in a second passage in parallel with the first passage to generate a damping force, in which the second damping force generation mechanism includes a first sub-valve provided on one side of the second passage formed in the valve seat member and a second sub-valve (provided on the other side thereof, and a bottomed cylindrical cap member having an outer cylindrical part and a bottom part, and the cap member includes an inner cylindrical part into which the piston rod is able to be inserted formed on an inner circumferential side of the bottom part and houses at least a part of the second damping force generation mechanism.

A valve seat member is provided in a cap member. A first sub valve is provided in another side chamber. A second sub valve is provided in a cap chamber formed between a bottom portion of the cap member and the valve seat member. In a second passage, an orifice is disposed on an upstream side or a downstream side from the first sub valve in flow by which the first sub valve is opened. In a region in which a piston speed is low, a valve of a second damping force generating mechanism is opened in a state in which a valve of a first damping force generating mechanism is closed. In a speed region in which the piston speed is higher than in another region, the valve of the first damping force generating mechanism and the valve of the second damping force generating mechanism are both opened.

Disclosed is a shock absorber including: a cylinder which is filled with a working fluid; a piston which is slidably provided in the cylinder and divides an inside of the cylinder into two chambers; a piston rod which is connected to the piston and extends outside the cylinder; a first passage and a second passage through which the working fluid flows due to movement of the piston; a first damping force generating mechanism which is provided in the first passage and generates a damping force; and a second damping force generating mechanism which is provided in the second passage and generates a damping force. The second damping force generating mechanism includes a sub valve provided on one side of the second passage, and a volume variable mechanism that changes a volume of a volume chamber provided in parallel with the second passage.

A shock absorber includes a first damping force generation mechanism provided in a first passage, and a second damping force generation mechanism provided in a second passage, in which the second damping force generation mechanism includes a first valve seat formed on a case member having a cylindrical part and a bottom part, a disc valve in which a separable part on an outer circumferential side is separably disposed on a first valve seat, and a second valve seat provided on a side of the disc valve opposite to the first valve seat and configured to support the disc valve on a radial inner side of the separable part, and the second passage includes a piston rod passage part formed by cutting out or penetrating the piston rod, and a chamber passage part which allows communication from the piston rod passage part to a case inner chamber.

This shock absorber includes: a friction member including an annular elastic rubber portion and an annular base portion (to which the elastic rubber portion is fixed; and a communication path that decreases a pressure difference between both sides of the friction member. The base portion includes an annular disk portion. The elastic rubber portion includes a minimum inner diameter portion on an inner peripheral side and includes an inner peripheral connection portion connected to an inner peripheral portion of the annular disk portion. A protrusion suppression structure portion that suppresses protruding of an inner peripheral surface formed from the minimum inner diameter portion toward the inner peripheral connection portion is provided at least partially in a circumferential direction between the inner peripheral connection portion and the minimum inner diameter portion of the elastic rubber portion.

A shock absorber includes a seal member that is slidably in contact with a piston rod, a friction member that is formed of an annular elastic rubber section slidably in contact with the piston rod and an annular base section to which the elastic rubber section is fixed, and an communication path that reduces pressure difference between both sides of the friction member in axial direction. The elastic rubber section is provided with a minimum inner diameter section, a first enlarged diameter section, and a second enlarged diameter section. A force is applied to the piston rod by the friction member such that movement in an outward direction of the cylinder becomes difficult and movement in an inward direction of the cylinder becomes easy.

A shock absorber includes a cylinder sealed with a working oil liquid, a piston slidably fitted in the cylinder, a piston rod connected to the piston and extended to the outside of the cylinder, and a plurality of passages through which the working oil liquid flows due to the sliding of pistons therein, and a damping force generating mechanism that is provided in a part of the passages and suppresses the flow of the working oil liquid to generate a damping force. The damping force generating mechanism includes a valve body through which the passage penetrates, an annular seat that projects from the valve body and surrounds the passage, and a disc that can be seated on the seat. A contact width at which the disc and the seat come into contact with each other is different depending on a position in the circumferential direction. As a result, it is possible to obtain a shock absorber capable of suppressing a sudden change in damping force before and after the opening of the disc valve without having a complicated structure.

A suspension apparatus includes a pair of hydraulic cylinders and a valve device provided between an upper chamber and a lower chamber of each of the hydraulic cylinders and configured to establish and block communication between these chambers. The valve device includes a first passage and an extension-side damping force generation mechanism. Hydraulic oil flows out from the upper chamber into the first passage due to movement of a piston in a cylinder of the hydraulic cylinder. The extension-side damping force generation mechanism includes a damping valve and a back-pressure chamber. The damping valve is disposed in the first passage and generates a damping force by restricting a flow of the hydraulic oil generated due to a sliding movement of the piston. The back-pressure chamber applies an inner pressure thereof to the damping valve in a valve-closing direction.

Suspension apparatus

A damper includes a first passage and a second passage in parallel, a first damping force generation mechanism of the first passage, a case member in which a portion of the second passage is formed, an annular disc disposed to face a bottom part in the case member to be able to be bent by a working fluid in the case member, a first chamber communicating with a first cylinder chamber and a second chamber communicating with a second cylinder chamber which are provided by the disc partitioning the inside of the case member, a first through hole provided in the bottom part of the case member to communicate with the second chamber, a bypass passage provided in parallel to the first through hole and configured to allow communication between the first chamber and the second cylinder chamber, and a second damping force generation mechanism provided in the bypass passage.

Damper

[Problem] The present invention provides a damping force adjustable shock absorber capable of reducing manufacturing cost. [Means for Solving] A shock absorberis configured in such a manner that a main valveis disposed below a piston valve, and a sub valvefor variably adjusting a set load of the main valveis provided in a piston caseabove the piston valve, with a first valve bodyof the sub valveslidably sealed to a case memberby a metal seal at only one portion. Due to the configuration, the shock absorbercan ease precision of components of the sub valve, thereby reducing the manufacturing cost.

Growing community of inventors

Zama, Japan

Mikio Yamashita