Kyb Corporation

Kayaba Industry Company, Ltd.

Kayaba Kogyo Kabushiki Kaisha

Tatsuya Masamura

Takashi Teraoka

Kenji Kitamura

Ryosuke Kamakura

Ken Mizumukai

Kazutaka Inamitsu

Futoshi Yoshida

Koji Takase

A suspension device includes an actuator device provided with an extensible/contractible actuator body interposed between a sprung member and an unsprung member of a vehicle, a pump that supplies fluid to the actuator body to extend or contract the actuator body, and a controller that controls a rotation number of the pump. The controller has a road surface state index obtainment unit that obtains a road surface state index and a target rotation number determination unit that determines a target rotation number of the pump on the basis of the road surface state index.

Suspension device and suspension control unit

A suspension device includes: a damper that has an extension-side chamber and a contraction-side chamber; an extension-side passage connected to the extension-side chamber; a contraction-side passage connected to the contraction-side chamber; a switching device that connects one of the extension-side passage and the contraction-side passage to the supply passage and connecting the other of the extension-side passage and the contraction-side passage to the discharge passage selectively; an extension-side damping element provided in the extension-side passage; a contraction-side damping element provided in the contraction-side passage; a control valve capable of adjusting a pressure in the supply passage; an intake check valve provided midway in the intake passage; and a supply-side check valve provided in the supply passage between the control valve and the pump.

Suspension device

Shock absorber including a suction passage allowing flow only from a reservoir towards a pressure side chamber, a rectifying passage allowing flow only from the pressure side chamber towards an expansion side chamber, and a damping force variable valve allowing flow only from the expansion side chamber towards the reservoir. A large pressure-side pressure chamber communicating with the pressure side chamber, and an outer peripheral expansion-side pressure chamber communicating with the expansion side chamber sandwich a free piston slidably moving within a bottom housing forming a pressure chamber. Because a pressure-side pressure-receiving area of the free piston is larger than an expansion-side pressure-receiving area in a contraction operation in which a piston moves downward, the free piston can move downward even in a uniflow-type shock absorber in which pressure in the expansion side and pressure side chambers become equal whereby damping force can be reduced during an input of high-frequency vibration.

Shock absorber

A shock absorber includes a suction passage permitting flow only from a reservoir toward a compression-side chamber, a rectification passage permitting flow only from the compression-side chamber toward an extension-side chamber, and a variable valve permitting flow only from the extension-side chamber toward the reservoir. A large chamber as a compression-side pressure chamber communicating with the compression-side chamber and an outer periphery chamber as an extension-side pressure chamber communicating with the extension-side chamber are partitioned in the shock absorber by a free piston that moves slidably within a bottom member serving as a housing. A compression-side pressure-receiving area of the free piston is larger than an extension-side pressure-receiving area. Therefore, even in the uniflow shock absorber with the extension-side chamber and the compression-side chamber at equal pressures during the contraction operation, the damping force is reduced under conditions in which high frequency is input since the free piston moves downward.

A shock absorber includes; a free piston that partitions the compression chamber into an expansion-side compression chamber and a contraction-side compression chamber; an expansion-side flow passage that connects the expansion-side chamber with the expansion-side compression chamber; a contraction-side flow passage that connects the contraction-side chamber with the contraction-side compression chamber; an expansion-side bypass valve provided in the expansion-side flow passage to admit only a flow directed from the expansion-side chamber to the expansion-side compression chamber and generate resistance; a contraction-side bypass valve provided in parallel with the expansion-side bypass valve to admit only a flow directed from the expansion-side compression chamber to the expansion-side chamber and generate resistance; an expansion-side elastic stopper configured to stop the free piston at an expansion-side stroke end; and a contraction-side elastic stopper configured to stop the free piston at a contraction-side stroke end.

A shock absorber includes at least one of an expansion-side sensitive unit and a contraction-side sensitive unit. The expansion-side sensitive unit has an expansion-side actuating chamber that communicates with an expansion-side chamber and a contraction-side chamber, an expansion-side free piston that partitions the expansion-side actuating chamber into a first expansion-side pressure chamber and a second expansion-side pressure chamber, and an expansion-side spring element configured to bias the expansion-side free piston to compress the first expansion-side pressure chamber. The contraction-side sensitive unit has a contraction-side actuating chamber that communicates with a contraction-side chamber and a reservoir, a contraction-side free piston that partitions the contraction-side actuating chamber into a first contraction-side pressure chamber and a second contraction-side pressure chamber, and a contraction-side spring element configured to bias the contraction-side free piston to compress the first contraction-side pressure chamber.

A shock absorber includes a suction passage allowing flow only from a reservoir towards a pressure side chamber, a rectifying passage allowing flow only from the pressure side chamber towards an expansion side chamber, and a damping force variable valve allowing flow only from the expansion side chamber towards the reservoir. Large, and small and outer peripheral chambers in a bottom housing sandwich a free piston. The small chamber communicates the outer peripheral chamber with the expansion side chamber. The large chamber communicates with the pressure side chamber through first and second valves. During a contraction in which a piston moves downward, even in a uniflow-type shock absorber in which pressure in the expansion side chamber and the pressure side chamber become equal, the free piston can move downward due to a difference in pressure-receiving areas. Even if a stretching speed reaches a high range, the first and second valves are opened, and damping force is reduced.

A shock absorbing device includes a cylinder. A partition wall member is inserted into the cylinder to be free to slide and partitions an interior of the cylinder into two operating chambers. A passage connects the two operating chambers. A free piston is inserted into a pressure chamber to be free to slide and partitions the pressure chamber into one chamber that communicates with one operating chamber via a one side flow passage and another chamber that communicates with the other operating chamber via another side flow passage. A spring element generates a biasing force for suppressing displacement of the free piston relative to the pressure chamber. One or both of a bypass flow passage that connects the other chamber and the one operating chamber and a bypass flow passage that connects the one chamber and the other operating chamber is provided. A relief valve is provided in the bypass flow passage.

Shock absorbing device

A shock absorber interposed in parallel with a suspension spring between a vehicle wheel and a vehicle body of a vehicle comprises a main piston () partitioning a cylinder () into a first operating chamber (R) and a second operating chamber (R), and connected to a piston rod (). The first operating chamber (R) and the second operating chamber (R) are connected by a laminated leaf valve (V, V) under a first flow resistance. A passage () connects one of the pressure chambers (RA, RB) partitioned by a free piston () and the first operating chamber (R) under a second flow resistance. A passage () connects the other of the pressure chambers (RA, RB) and the second operating chamber (R) under a third flow resistance. The shock absorber displays stable damping force characteristics as a result of a spring (S) supporting the free piston () in a predetermined neutral position.

Provided is a hydraulic shock absorber enabling an increase in a variable range of both damping forces produced in an extension stroke and a compression stroke thereof. A cylinder () filled with hydraulic oil is divided into first and second oil chambers () and () by a piston (), and a main valve () is disposed in a main passage () of the piston (). An extension side pilot chamber () urging a spool () in a valve-closing direction at pilot pressure introduced thereinto through a first orifice () in the extension stroke and a compression-side pilot chamber () urging the spool () in the valve-closing direction at pilot pressure introduced thereinto through a second orifice () in the compression stroke are formed at a back face of the spool () of the main valve. Also, the shock absorber comprises a pressure-receiving portion for receiving high pressure in the extension stroke and urging the spool () in a valve-opening direction against the pilot pressure and a pressure-receiving portion for receiving high pressure in the compression stroke and urging the spool () in the valve-opening direction against the pilot pressure. In addition, the shock absorber comprises an extension-side poppet valve () for regulating the pilot pressure in the extension stroke, a compression-side poppet valve () for regulating the pilot pressure in the compression stroke, and a solenoid () for urging to reduce initial loads of springs () of the extension-side and compression-side poppet valves () and () by passing current therethrough.

Hydraulic shock absorber

A damping force control device () for a shock absorber (Dn) interposed between a sprung member (Bn) and an unsprung member (Wn) of a vehicle (A) comprises a damping force varying mechanism () which supplements a minimum damping force (Fdn) that can be generated by the shock absorber (Dn) with a variable damping force (Fcn). The device () comprises a control portion () which calculates a deviation (&#x3b5;n) between a damping force target value (Fsn) and the minimum damping force (Fdn) (S), and open-loop controls the damping force varying mechanism () using a variable damping force (Fcn) calculated on the basis of the deviation (&#x3b5;n) such that the damping force generated by the shock absorber (Dn) coincide with the damping force target value (Fsn) (S-S), thereby optimizing damping force control of the shock absorber (Dn), which has a non-linear damping characteristic.

Control device and method for shock absorber

In a damping force generator for a hydraulic damper, the valve is protected from pressure rise in the damper and its durability is thereby enhanced. The damping force characteristics can be vary in stepwise fashion by providing a main leaf valve and a sub-leaf valve which closes an opening A formed in the main leaf valve and the approximate mid-point of the main leaf valve is supported by a plurality of intermediate seat surfaces from the side of a port The outer circumference of a main leaf valve is supported by an outer circumferential seat surface and the outer circumference of a sub-leaf valve extends outwards to the vicinity of a part where the outer circumference of the main leaf valve and the outer circumferential seat surface overlap.

Damping force generator

A suspension apparatus with a pair of hydraulic dampers 1 disposed on left and right sides of a vehicle, an upper end side of which is connected to a vehicle body side and a lower end side is connected to an axle side, and a pressure regulating cylinder 2 communicating with piston side oil chambers a of the pair of hydraulic dampers 1. The pressure regulating cylinder 2 has a free piston 26 slidably disposed within a cylinder body 24 and defining a front side chamber h and a back side chamber i within the cylinder body 24. The free piston 26 is slidably encased in a cylinder member and has a partitioning member 27 for defining a closed chamber j and an open chamber k communicating with a front side chamber h on the inner peripheral side of the free piston 26. The partitioning member 27 has a damping valve 4 which communicates between the closed chamber j and the open chamber k, and has a proximal end connected to an extreme end of a rod body 29 elastically supported on the cylinder body 24. The front side chamber h communicates with a piston side oil chamber a of one hydraulic damper 1. The closed chamber j communicates with a piston side oil chamber a of the other hydraulic damper 1 through a through-hole 29b bored in an axial central part of the rod body 29.

Suspension apparatus

The posture of a vehicle is controlled using a specific variable damping force damper without the necessity of changing over the variable damping force damper frequently and at a high rate and without using a vehicle height sensor. A variable damping force damper U having at least two change-over modes including a mode in which the compression side damping force is soft when the extension side damping force is hard and another mode in which the compression side damping force is hard when the extension side damping force is soft is interposed between a vehicle body D and a wheel E. The variable damping force damper U is changed over by means of an acceleration sensor J mounted on the vehicle body D and a controller M including an integrator P for converting a signal from the acceleration sensor J into a velocity signal and a calculation processing circuit Q for outputting a changing over signal to the variable damping force damper U in accordance with the velocity signal from the integrator P.

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Gifu, Japan

Tatsuya Masamura