An apparatus for damping vibrations includes an inertial mass disposed in a cavity in a rotatable downhole component, the rotatable component configured to be disposed in a borehole in a subsurface formation, such as a resource bearing formation, the inertial mass coupled to a surface of the cavity by a damping fluid and configured to move within the cavity relative to the downhole component. The apparatus also includes a damping fluid disposed in the cavity between the inertial mass and an inner surface of the cavity, where rotational acceleration of the rotatable downhole component causes shear in the damping fluid to dissipate energy from rotational acceleration of the rotatable downhole component and causing the rotational acceleration to be reduced.

A damper device includes a damper unit and a torque limiter unit. The damper unit includes an output plate, an elastic member, first and second input plates. The torque limiter unit includes a pressure plate, first and second side plates. The first side plate has an inner diameter equal to an outer diameter of the output plate. The second side plate has an inner diameter equal to an outer diameter of the first input plate. The pressure plate has an inner diameter equal to an outer diameter of the second input plate. An inner-peripheral surface of the first side plate is not opposed to an outer-peripheral surface of the output plate. An inner-peripheral surface of the second side plate is not opposed to an outer-peripheral surface of the first input plate. An inner-peripheral surface of the pressure plate is not opposed to an outer-peripheral surface of the second input plate.

Provided is a damper device including a first rotary body that is rotated about a rotational axis; a second rotary body that is rotated relative to the first rotary body; an elastic mechanism portion; and a control plate that includes a radially extending portion that abuts against the elastic mechanism portion and an axially extending portion that is partially housed in at least one of the first rotary body and the second rotary body. The control plate is disposed in only one of the first housing space and the second housing space in the axial direction. The device also includes a first sliding portion that generates first sliding torque; and a second sliding portion that generates second sliding torque. The first sliding torque and the second sliding torque are generated when the first rotary body and the second rotary body are rotated relative to each other.

The disclosure provides a drive device including a gear, a bearing, and a motor rotor. The gear includes an installation hole. The bearing is disposed in the installation hole of the gear and includes a rotation hole, a sliding groove, and a drive assembly. The sliding groove communicates with the rotation hole, and the drive assembly is movably disposed in the sliding groove. The motor rotor rotatably passes through the rotation hole of the bearing. The drive assembly is moved to lock the bearing by the rotation of the motor rotor, and the torsion force of the motor rotor is transmitted to the gear through the bearing.

A drivetrain for motor vehicle including an electric motor and a reduction mechanism designed to transmit the driving torque to the wheels of the motor vehicle. The electric motor includes a rotor equipped with a rotor shaft, the rotor shaft being rotationally coupled to a primary shaft of the reduction mechanism. The drivetrain further includes a dynamic absorber in torsion, the dynamic absorber in torsion having a support element, an inertial mass which is mounted with the ability to rotate about an axis X with respect to the support element and elastic members which oppose the relative rotation of the inertial mass with respect to the support element about said axis X.

Various embodiments of the present technology may provide methods and apparatus for a 3D-printed spring. The 3D-printed spring may be formed from a plurality of toroidal elements spaced apart from each other and connected with a plurality of connectors. Each connector connects one toroidal element to a directly adjacent toroidal element.

A lamina emergent torsional (LET) joint that includes an integrated membrane to reduce, or eliminate, certain unwanted motions and/or displacements associated with the operation of the LET joint is disclosed. The membrane-integrated LET joint (i.e., M-LET) can be used as a hinge for a lamina emergent mechanism and/or as a surrogate fold for an origami application to ensure accurate and repeatable transitions from a planar (i.e., lamina) state to a non-planar (i.e., lamina-emergent) state, and vice versa.

A flexible flywheel includes: a shaft fastening portion fixed to an end portion of an engine crankshaft; an annular inertia ring provided around the shaft fastening portion; a plurality of elastic spoke portions that extend in the radial direction between the shaft fastening portion and the inertia ring and connect the shaft fastening portion and the inertia ring to each other, and that absorb vibration acting on the crankshaft by undergoing deflection; and weight portions provided between adjacent elastic spoke portions, side edge-side boundary ends, to which boundaries with the weight portions are connected, are provided on both sides edges of the elastic spoke portion, respectively, when the elastic spoke portions are vibrated, stress concentrates on the side edge-side boundary ends.

A damper device includes a first rotor, a second rotor, a plurality of elastic members and a stopper mechanism. The stopper mechanism includes a plurality of first cutouts, a plurality of second cutouts and a plurality of stop members. A pair of the first and second cutouts is provided on both circumferential sides of each of a plurality of accommodation portions of the second rotor so as to circumferentially extend therefrom. The stop members are fixed to the first rotor. Each stop member is circumferentially movable within the pair of the first and second cutouts. The second rotor includes a first protruding portion circumferentially protruding on one of a pair of pressing surfaces of each accommodation portion. Each of the first cutouts, which is a hole, extends at an end thereof located closer to each accommodation portion toward the first protruding portion.

A damper device includes a first rotor, a second rotor, a plurality of elastic members, and a spring seat. The spring seat includes an end surface support portion and an outer periphery support portion. The end surface support portion includes a recess on a radially middle part thereof. The recess is recessed toward at least one of the elastic members. The end surface support portion supports one end surface of the at least one of the elastic members. The end surface support portion is supported by a pressing surface of a first accommodation portion of the first rotor and a pressing surface of a second accommodation portion of the second rotor. The outer periphery support portion supports part of a radially outer part of the at least one of the elastic members.