Abstract: When a preview sensor acquires undulation information regarding a convex portion of a road surface, an electric actuator expands during a predetermined period of time between that point and a point immediately before the wheel rides on the convex portion, whereby ascending velocity of a sprung member increase. Therefore, when the wheel rides on the convex portion, the sprung member reaches estimated unsprung ascending velocity as a result of the expansion of the electric actuator up to that point. Accordingly, in the case where the wheel rides on the convex portion and an unsprung member is pushed up, a change in the sprung vertical velocity caused by application of the pushing up force to the sprung member is reduced because the sprung member ascends at the estimated unsprung ascending velocity. Therefore, riding quality is improved.

Abstract: A control system for a resilient support mechanism such as a suspension mechanism of a wheeled vehicle including a damper disposed between an unsprung mass member and a sprung mass member of the vehicle, wherein a damping coefficient of the damper is divided into a linear portion and a nonlinear portion, and wherein the nonlinear portion of the damping coefficient is defined as a control input u and applied with a frequency weight Wu(s), while a vertical velocity of the sprung mass member, a relative velocity of the sprung mass member to the unsprung mass member and a vertical acceleration of the sprung mass member are defined as an evaluation output zp and applied with a frequency weight Ws(s).

Abstract: An actuator disposed within a piston rod of a variable-damping force shock absorber has coils mounted at an inner peripheral face of the piston rod, permanent magnets disposed facing a stator, and a cylindrical body supported rotatably about the piston rod axis. The permanent magnets are fixed to a side face of an upper portion of the cylindrical rotating body and an insert hole into which an upper end portion of a shaft is inserted extends through a lower portion of the rotating body. A female thread is formed in the insert hole, and engaged with a male thread formed on an outer peripheral face of the upper end portion of the shaft. A spool is mounted on a lower end portion of the shaft so that, as the rotating body rotates, the spool moves in the direction of the piston rod axis and thereby changes the opening of a communication passage between upper and lower chambers of a cylinder. The piston rod of the variable-damping force shock absorber has a reduced diameter.

Abstract: Shock absorber including a cylinder body and a piston cooperating to two chambers one and the other of which respectively function as high-pressure and low-pressure chambers, a piston rod fixed to the piston, and a damping force control device including (i) a hard valve which permits a flow of a working fluid from the high-pressure chamber toward the low-pressure chamber when a difference between fluid pressures in the high-pressure and low-pressure chambers is larger than a predetermined threshold, (ii) a soft valve which permits the fluid flow from the high-pressure chamber toward the low-pressure chamber when the pressure difference is not larger than the threshold, and (iii) a flow restricting fluid passage disposed in parallel with at least one of the hard and soft valves, and wherein at least one of the hard and soft valves and the soft valve permits a flow of the fluid therethrough during both elongation and contraction of the shock absorber.

Abstract: A suspension system of an automotive vehicle including a spring disposed between an unsprung mass and a sprung mass for resiliently supporting thereon the sprung mass and a damping force generating mechanism arranged in parallel with the spring for absorbing vibration of the sprung mass relative to the unsprung mass, wherein the suspension system is provided with a spring element disposed in series with the damping force generating mechanism between the unsprung and sprung masses and an electrically operated control mechanism for controlling a spring coefficient of the spring element.