Hitachi Automotive Systems, Ltd.

Hitachi, Ltd.

Hitachi Astemo Ltd.

Tokico, Ltd.

Yohei Katayama

Takashi Nezu

Hiroyuki Yabe

Takao Nakadate

Hiroki Ohara

Ryusuke Hirao

Shunsuke Mori

Shigeo Katayama

Toru Uchino

Yusei Kimura

Hiroyuki Hayama

Hiroyuki Yamaguchi

Shinji Seto

Mikio Yamashita

Fumiyuki Yamaoka

Yuichiro Tanaka

Hideki Hata

Osamu Yuno

Naofumi Harada

Koichi Yamaka

Umi Tanabe

Kosuke Kadokura

Sadatomo Matsumura

Milton Muzvidziwa

Kenji Noda

Osamu Shioume

Hiroyuki Matsumoto

Yoshie Midorikawa

Norio Nakazato

Motohiro Hirao

Satoshi Shimazaki

Teruaki Yamanaka

A piston bolt is formed by divided first and second members, and a first small-diameter portion and a large diameter portion of a common passage are formed in the first member and a second small-diameter portion of the common passage is formed in the second member. This configuration allows the common passage to be processed using a general-purpose method and tool and contributes to reducing the man-hours for the piston bolt.

Shock absorber

The solenoid coil includes a coil having a first end surface and a second end surface on its both ends in an axial direction, a member which is in contact with the first end surface, and has a groove through which the wire material of the coil passes, and an insulating resin formed to coat at least an outer circumferential surface and the second end surface of the coil. The resin with a substantially U-shaped section is continuously coated on at least a part of an inner circumferential surface of the coil via an area from the outer circumferential surface to the second end surface.

Solenoid coil

The present invention provides a shock absorber capable of improving responsiveness during an extension stroke without leading to an increase in an axial length. A shock absorber includes a chamber provided on a one-side end of a pilot valve and disposed in communication with a cylinder upper chamber, a communication passage configured to establish communication between the chamber and a cylinder lower chamber via a compression-side passage, and a check valve configured to permit hydraulic fluid in the communication passage to flow into the cylinder lower chamber during an extension stroke.

A flow of hydraulic oil induced by sliding movement of a piston in a cylinder is controlled by a damping force generating mechanism to generate a damping force. A flow of hydraulic oil from a casing of the damping force generating mechanism toward a reservoir is regulated by a passage groove formed on the bottom of the casing so as to be directed downward in the reservoir. Thus, the hydraulic oil is efficiently supplied to a base valve from the damping force generating mechanism even when the hydraulic oil is sucked from the reservoir into a cylinder lower chamber through a passage in the base valve during the extension stroke of a piston rod. Therefore, it is possible to suppress a sharp reduction in pressure in the lower part of the reservoir and hence possible to suppress the occurrence of aeration and to obtain stable damping force characteristics.

A shock absorber includes a reservoir between a cylinder and an outer tube, in which hydraulic liquid and gas are sealed; a middle tube between the cylinder and the outer tube; a connecting pipe in the lateral wall of the middle tube, which includes a tip end extending toward the outside of the outer tube; an opening in the outer tube, allowing hydraulic liquid to flow from the outside of the outer tube into the reservoir through the outer side of the connecting pipe; and a partition member in the reservoir, which includes a partition wall that configured to regulate hydraulic liquid's upward flow from the opening in the reservoir. The partition member is made of flexible resin or rubber, provided with a fitting hole, and fitted to the connecting pipe with interference with the connecting pipe inserted through the hole.

A shock absorber including a damping force generation mechanism () includes a spring member () having radially extending spring portions () having high spring constants and circumferentially extending spring portions () having low spring constants. The radially extending spring portions and the circumferentially extending spring portions are integrally configured so that biasing forces thereof act dynamically linearly. An annular stepped portion limits strokes of the circumferentially extending spring portions and is provided on a cylindrical wall portion of a pilot body. As a result, within a range of damping force control, only the radially extending spring portions of the spring member are elastically deformed, whereby the durability of the spring member is enhanced, and only biasing forces of the radially extending spring portions of the spring member act on a pilot valve member, and thereby variation in a damping force is reduced so that the performance is improved.

[Object] The present invention provides a suspension control apparatus that allows miniaturization of a solenoid valve. [Solution] When a controller is started up by a power source controller (a power source unit), the controller switches a control current from 0 ampere to a maximum current value I6 at the same time as the startup. After that, the control shifts to normal control. As a result, even if a hysteresis of a damping force characteristic is large relative to the control current, it is possible to promptly move a solenoid valve to a position to be used in the normal control.

Suspension control apparatus

During either of the extension and compression strokes, hydraulic liquid flows from a cylinder upper chamber into a reservoir through an annular passage and a damping force control mechanism, and a damping force is generated by the damping force control mechanism. The check valve is provided with a sub-check valve in parallel thereto, which opens in a very low piston speed region to allow the hydraulic liquid to flow through an orifice passage. These check valves are opened successively as the piston speed increases, thereby generating a sufficiently small damping force in the very low piston speed region during the compression stroke of the piston rod, and obtaining a moderate damping force when the piston speed increases.

Damping force control type shock absorber

A damping force adjustable hydraulic shock absorber, in which response delay of a pressure control valve and self-excited vibration of a valve body can be prevented. A damping force is generated by controlling an oil flow between an annular oil passage () and a reservoir () generated by sliding movement of a piston in a cylinder with use of a back-pressure type main valve () and a pressure control valve (). The damping force is directly generated by the pressure control valve, and valve-opening pressure of the main valve is adjusted by adjusting an inner pressure of a back-pressure chamber. In the pressure control valve, a valve spring is disposed between a valve body and a plunger. A mass of the valve body is sufficiently less than that of the plunger, and a spring stiffness of the valve spring is higher than that of a plunger spring.

Damping force adjustable shock absorber

[Object] The present invention provides a suspension control apparatus that allows miniaturization of a solenoid valve. [Solution] When a controller is started up by a power source controller (a power source unit), the controller switches a control current from 0 ampere to a maximum current value Iat the same time as the startup. After that, the control shifts to normal control. As a result, even if a hysteresis of a damping force characteristic is large relative to the control current, it is possible to promptly move a solenoid valve to a position to be used in the normal control.

A frequency-dependent mechanism provided at the lower end of a piston rod includes a tubular housing displaceable in an inner tube, together with the piston rod as one unit, and further includes a free piston and O-rings. A shutter of a passage area varying mechanism is provided with an axially extending inner hole, orifices, and oil grooves. The opening area between oil holesC and the orificesB is changed according to the rotational position of the shutter. The opening area between oil holesD andE and the oil groovesC andD and the opening area between oil holesF andG and the oil groovesE andF are also variably adjusted according to the rotational position of the shutter.

A fluid pressure shock absorber in which valve opening of the main valve is controlled by an inner pressure of a backpressure chamber. A first piston () and a second piston () coupled to a piston rod () are fitted in a cylinder () such that a piston chamber (C) is defined between the first and second pistons. An extension-side main valve () and a compression-side main valve () are provided in the piston chamber (C). Valve opening of the main valves is controlled by an extension-side backpressure chamber () and a compression-side backpressure chamber (). A compression-side check valve () and an extension-side check valve () are provided at the first piston () and the second piston (). During an extension stroke of the piston rod (), the compression-side check valve () is closed, whereby action of a pressure of a cylinder upper chamber (A) on the compression-side main valve () is prevented. During a compression stroke of the piston rod (), the extension-side check valve () is closed, whereby action of a pressure of a cylinder lower chamber (B) on the extension-side main valve () is prevented. Accordingly, it is possible to generate a stable damping force, and enhance durability of the extension-side main valve () and the compression-side main valve ().

Fluid pressure shock absorber

A first piston and a second piston coupled to a piston rod are fitted in a cylinder, and an intermediate chamber is formed between the first and second pistons. A compression-side check valve and an extension-side check valve are provided at the first piston and the second piston. An extension-side main valve and a compression-side main valve are disposed in the intermediate chamber. A downstream side of a damping force adjusting valve is connected to the intermediate chamber. Inner pressures of an extension-side backpressure chamber and a compression-side backpressure chamber are adjusted by the damping force adjusting valve, whereby valve opening of the extension-side and compression-side main valves is controlled. Hydraulic fluid of the downstream side of the damping force adjusting valve is first sent into the intermediate chamber, and then is sent to a cylinder upper chamber or a cylinder lower chamber. Due to this arrangement, it is possible to prevent a sudden drastic change in a hydraulic fluid pressure and thereby to generate a stable damping force.

Damping force adjustable fluid pressure shock absorber

A piston connected to a piston rod is slidably fitted in a cylinder having a hydraulic fluid sealed therein. First and second poppet valves having different valve opening characteristics are provided in first and second extension main passages, respectively. A pilot control valve is provided in a sub-passage. The control pressure of the pilot control valve is adjusted by a proportional solenoid, thereby controlling damping force. At the same time, the pressure at the upstream side of the pilot control valve is introduced into back-pressure chambers to adjust the valve opening pressures of the first and second poppet valves. Because the first and second poppet valves are sequentially opened or closed, damping force can be controlled stepwisely, and ideal damping force characteristics can be obtained.

Growing community of inventors

Yokohama, Japan

Yohei Katayama