A system for assisting a user in moving a device relative to a structure comprises a magnetorheological (MR) fluid actuator unit including at least one torque source and at least one MR fluid clutch apparatus having an input coupled to the at least one torque source to receive torque from the at least one torque source, the MR fluid clutch apparatus controllable to transmit a variable amount of assistance force via an output thereof. An interface is configured for coupling the output of the at least one MR fluid clutch apparatus to the device or surrounding structure. At least one sensor provides information about a movement of the device. A processor unit for controlling the at least one MR fluid clutch apparatus in exerting the variable amount of assistance force as a function of said information, wherein the system is configured for one of the MR fluid actuator unit and the interface to be coupled to the structure, and for the other of the MR fluid actuator unit and the interface to be coupled to the device for the assistance force from the MR fluid actuator unit to assist in moving the device.

A viscous clutch includes an input member, an output member, a working chamber defined between the input member and the output member, a reservoir to hold a supply of a shear fluid fluidically connected to the working chamber by a fluid circuit, a valve that is electromagnetically actuatable to selectively control a flow of the shear fluid along the fluid circuit, a control coil assembly, and a securing mechanism. The control coil assembly includes a modular center hub removably attached to the input member, an electromagnetic coil and a coil bearing rotatably supporting the electromagnetic coil on the modular center hub. The securing mechanism is removably attached to the input member radially inward of the working chamber and the reservoir, and includes a radially outwardly extending flange.

A viscous clutch includes an input member, an output member, a working chamber defined between the input member and the output member, a reservoir to hold a supply of a shear fluid fluidically connected to the working chamber by a fluid circuit, a valve that is electromagnetically actuatable to selectively control a flow of the shear fluid along the fluid circuit, a control coil assembly, and a securing mechanism. The control coil assembly includes a modular center hub removably attached to the input member, an electromagnetic coil and a coil bearing rotatably supporting the electromagnetic coil on the modular center hub. The securing mechanism is removably attached to the input member radially inward of the working chamber and the reservoir, and includes a radially outwardly extending flange.

An actuator assembly can include a housing, first and second pistons, and spring. The housing can include first and second cylinders disposed about an axis. The first piston and cylinder can define a first chamber in fluid communication with an inlet. The second piston and cylinder can define a second chamber in fluid communication with an outlet. Opposite ends of the spring can be coupled for axial translation with the first and second piston, respectively. The spring can translate the first piston to provide high volume, low pressure fluid to the outlet when a pressure in the first chamber is less than a predetermined pressure. When the pressure in the first chamber is equal to, or greater than, the predetermined pressure and the second piston is translated in the first axial direction, the spring can compress and the second piston can provide low volume, high pressure fluid to the outlet.

A magnetorheological fluid clutch apparatus comprises a stator having at least an annular wall; a first rotor rotatably mounted to the stator, the first rotor having at least one first shear surface; a second rotor rotatably mounted to the stator for rotating about a common axis with the first rotor, the second rotor having at least one second shear surface opposite the at least one first shear surface, the shear surfaces separated by at least one annular space. A magnetorheological (MR) fluid is in an MR fluid chamber including the at least one annular space, the MR fluid configured to generate a variable amount of torque transmission between the rotors when subjected to a magnetic field. An inner magnetic core and an outer magnetic core with an annular cavity therebetween receive the annular wall of the stator, the inner magnetic core and the outer magnetic core connected to at least one of the rotors to rotate therewith so as to be rotatably mounted to the stator. Outer and inner fluid gaps are between the inner magnetic core and the annular wall, and between the outer magnetic core and the annular wall, the outer and inner fluid gaps filled with at least one fluid. At least one coil is supported by the annular wall and actuatable to deliver a magnetic field through the MR fluid, the magnetic field following a path comprising the annular wall, the outer fluid gap, the outer magnetic core, the at least one first shear surface and the at least one second shear surface, the inner magnetic core and the inner fluid gap, wherein one of the rotors is adapted to be coupled to a power input and the other of the rotors is adapted to be connected to an output whereby actuation of the at least one coil results in a variation of torque transmission between the rotors.

A magnetorheological fluid clutch apparatus comprises a stator having at least an annular wall; a first rotor rotatably mounted to the stator, the first rotor having at least one first shear surface; a second rotor rotatably mounted to the stator for rotating about a common axis with the first rotor, the second rotor having at least one second shear surface opposite the at least one first shear surface, the shear surfaces separated by at least one annular space. A magnetorheological (MR) fluid is in an MR fluid chamber including the at least one annular space, the MR fluid configured to generate a variable amount of torque transmission between the rotors when subjected to a magnetic field. An inner magnetic core and an outer magnetic core with an annular cavity therebetween receive the annular wall of the stator, the inner magnetic core and the outer magnetic core connected to at least one of the rotors to rotate therewith so as to be rotatably mounted to the stator. Outer and inner fluid gaps are between the inner magnetic core and the annular wall, and between the outer magnetic core and the annular wall, the outer and inner fluid gaps filled with at least one fluid. At least one coil is supported by the annular wall and actuatable to deliver a magnetic field through the MR fluid, the magnetic field following a path comprising the annular wall, the outer fluid gap, the outer magnetic core, the at least one first shear surface and the at least one second shear surface, the inner magnetic core and the inner fluid gap, wherein one of the rotors is adapted to be coupled to a power input and the other of the rotors is adapted to be connected to an output whereby actuation of the at least one coil results in a variation of torque transmission between the rotors.

A viscous clutch includes an input member, an output member, a working chamber defined between the input member and the output member, a reservoir to hold a supply of a shear fluid fluidically connected to the working chamber by a fluid circuit, a valve that is electromagnetically actuatable to selectively control a flow of the shear fluid along the fluid circuit, a control coil assembly, and a securing mechanism. The control coil assembly includes a modular center hub removably attached to the input member, an electromagnetic coil and a coil bearing rotatably supporting the electromagnetic coil on the modular center hub. The securing mechanism is removably attached to the input member radially inward of the working chamber and the reservoir, and includes a radially outwardly extending flange.

A viscous clutch includes an input member, an output member, a working chamber defined between the input member and the output member, a reservoir to hold a supply of a shear fluid fluidically connected to the working chamber by a fluid circuit, a valve that is electromagnetically actuatable to selectively control a flow of the shear fluid along the fluid circuit, a control coil assembly, and a securing mechanism. The control coil assembly includes a modular center hub removably attached to the input member, an electromagnetic coil and a coil bearing rotatably supporting the electromagnetic coil on the modular center hub. The securing mechanism is removably attached to the input member radially inward of the working chamber and the reservoir, and includes a radially outwardly extending flange.

An actuator assembly including a housing. The housing having an actuator component, an armature, and at least a portion of a sensor disposed therein. The armature is selectively positionable between a first position and a second position. The sensor includes at least one sensing element disposed within the housing adjacent to the armature. The sensing element has a physical property which varies based upon a position of the armature within the housing.

The invention relates to an electrohydraulic actuator comprising a hydraulic piston, a spindle drive for moving the piston along an axis of rotation, wherein the spindle drive comprises a spindle and a nut, and a worm wheel, which is coaxially attached to the nut. Furthermore, an electric motor having a worm, which meshes with the worm wheel, is provided. The nut is radially and axially supported by means of a bearing. In addition, there is a single-armed rotation-prevention mechanism in order to prevent the spindle from rotating. An angle with respect to the axis of rotation is included between a point of action of the worm on the worm wheel and the effective direction of the rotation-prevention mechanism, wherein the angle is selected in such a way that, for a predetermined torque acting on the nut, a radial force acting on the piston is minimized.