An electromagnetic actuator including: an inner axial member; an outer housing member; a stator and a mover configured to have electromagnetic oscillation force exerted between them, each being securely assembled to different one of the members; and plate springs elastically connecting the members at opposite axial sides thereof, wherein the outer housing member includes an outer tubular member and first and second lid members attached to opposite axial openings thereof, and a first axial side of the outer tubular member has a small-diameter constricted section, and the constricted section has axially inner and outer stepped walls, and the axially inner stepped wall positions a first axial side of the stator or the mover assembled to the outer housing member, while the axially outer stepped wall and the first lid member support a periphery of the corresponding plate spring.

An electromagnetic actuator including: an outer housing member wherein outer peripheral edges of lid members are fixed respectively to opposite axial sides of the outer tubular member; an inner axial member elastically-connected to the outer housing member by plate springs at opposite axial sides thereof such that central portions of the plate springs are attached to the inner axial member, while outer peripheral edges of the plate springs are clamped and fixed between the outer tubular member and the respective lid members; a stator and a mover having electromagnetic oscillation force between them securely-assembled to the outer housing member and the inner axial member; and integrally-formed seal rubber and stopper rubber provided at inner faces of the lid members to seal a fixation part to the outer tubular member and to cushion strike of the inner axial member against the lid members, respectively.

An electrically driven actuator includes a vibration damping device; and an electrically driven unit operated by using electricity. The vibration damping device includes a vibration absorbing unit provided between a first support and a second support provided to face the first support, and expanding and contracting by using electricity, a measurement unit that measures vibrations of the second support, and a control unit that electrically controls the vibration absorbing unit to cancel the vibrations of the second support which are measured by the measurement unit. The electrically driven unit includes a housing provided on a fixed side, a shaft movable in an axial direction which is a direction toward a movable side opposite to the fixed side with respect to the housing, and a drive unit provided between the housing and the shaft, and driving the shaft with respect to the housing.

A piston of a magnetorheological fluid shock absorber is provided with a piston core having a small diameter portion mounted on an end portion of the piston rod, an enlarged diameter portion formed continuously in an axial direction with a diameter larger than the small diameter portion and forming a stepped portion, and a large diameter portion formed continuously in the axial direction with a diameter larger than the enlarged diameter portion and having a coil; a ring body surrounding the outer periphery of the piston core and forming a flow passage of the magnetorheological fluid between itself and the large diameter portion; a plate formed annularly and arranged on the outer periphery of the small diameter portion and mounted on one end of the ring body; and a stopper mounted on the small diameter portion and sandwiching the plate between the stopper and the stepped portion.

A multi-dimensional magnetic negative-stiffness mechanism and a multi-dimensional magnetic negative-stiffness vibration isolation system composed thereof are provided. The multi-dimensional damping system is composed of a positive-stiffness mechanism, a multi-dimensional negative-stiffness mechanism, a floating frame, a vibration isolated body, and a mounting base. The positive-stiffness mechanism is a traditional elastic element connected to the vibration isolated body and the mounting base, and provides supporting forces in an X direction, a Y direction, and a Z direction, and a basic vibration isolation function. The multi-dimensional negative-stiffness mechanism is composed of at least two negative-stiffness magnetic groups. Each negative-stiffness magnetic group may provide one-dimensional or two-dimensional negative stiffness. Through a series connection of the at least two negative-stiffness magnetic groups, a two-dimensional or three-dimensional negative-stiffness effect may be implemented to improve the vibration isolation performance of the system in multiple dimensions.

Provided is a sound reduction or vibration damping apparatus that has a new sound control principle where the sound control principle is totally different from a known passive or active sound control apparatus. A sound reduction or vibration damping apparatus 1 includes a mass portion 11, spring portions 12a and 12b placed between the mass portion 11 and a structural member 13, and a control unit 4 for causing the spring constants of the spring portions 12a and 12b to continue changing. The sound reduction or vibration damping apparatus 1 is mounted on the structural member 13 to reduce sound passing through the structural member 13 or sound generated from the structural member, or damp the vibration of the structural member 13.

Rotationally symmetric dampers (FIG. 3A) of a new type for eliminating and avoiding vibrations in machines and installations, particularly wind turbines. The damping occurs by magnetically generated eddy currents. In addition, vibration absorbers, particularly pendulum absorbers (7), are equipped with such magnetic dampers, and to installations, particularly wind turbines, that are exposed to vibratory forces and that comprise such vibration absorbers.

A vibration reduction assembly (200) including: (i) a shaft (240); (ii) a first component (210) positioned along the shaft and having a first face (212) comprising a plurality of magnets (230) positioned to alternate between a magnet having a first magnetic pole (232) at the first face and a magnet having the opposite magnetic pole (234) at the first face; and (iii) a second component (220) positioned along the shaft and having a first face (222) comprising a plurality of ferromagnetic extensions (260), wherein the first face of the first component is separated from the first face of the second component by a gap (280) having an adjustable first distance, and wherein a pair of the plurality of magnets interact via magnetic force with a respective one of the ferromagnetic extensions to reduce vibrations from a drivetrain to a housing portion of the personal care device.

To solve a problem, for example, in which holding a movable mass becomes difficult because the spring characteristics of a rubber constituting a basis are set low in order to set the characteristic value at a low value. In a first dynamic vibration absorber including a movable mass that is coupled to a vibration damping target member via an MRE as a first elastic member having elastic characteristics variable with a magnetic field, and being capable of varying a vibration characteristic value of the movable mass by controlling the magnetic field, the dynamic vibration absorber has a second elastic member different from the MRE, and the vibration damping target member and the movable mass are elastically-coupled to each other via the second elastic member.

The present disclosure provides a single-degree-of-freedom (SDOF) magnetic damping shock absorber based on an eddy current effect, comprising a lower plate, a ring-shaped magnet a, a ring-shaped magnet b, an aluminum cylinder, a bottom copper sheet, a copper sheet, a top copper sheet, a bearing seat, a linear bearing, a bearing end cap, a load, a piston shaft, a stepped shaft, a fixed collar, a coil spring, a lower clamping shaft, and fixing screws. When the shock absorber is working, the ring-shaped magnet a keeps stationary at the lower end and the ring-shaped magnet b reciprocates in the vertical direction. Both magnets are arranged in a mutual attraction manner. Under the action of a time-varying electromagnetic field generated by the relative movement of the ring-shaped magnet b, the copper sheet arranged between the two ring-shaped magnets generates eddy current damping. The movement of the ring-shaped magnet b is inhibited.