Systems and methods for damping torsional oscillations of downhole systems are described. The systems include a downhole drilling system disposed at an end of the downhole system in operative connection with a drill bit. A damping system is installed on the downhole drilling system, the damping system having at least one damper element configured to dampen at least one HFTO mode. At least one mode-shape tuning element is arranged on the drilling system. The at least one mode-shape tuning element is configured and positioned on the drilling system to modify at least one of a shape of the HFTO mode, a frequency of the HFTO mode, an excitability of the HFTO mode, and a damping efficiency of the at least one damper element.

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 shaft coupling includes a drive hub that is coupled to a drive shaft to rotate integrally with the drive shaft, a driven hub that is coupled to a driven shaft to rotate integrally with the driven shaft, and a rotation transmission portion that transmits rotation between the drive hub and the driven hub. A dynamic vibration absorber is integrally coupled to a section of at least one of the drive hub and the driven hub. The section is an uninvolved section that is not involved in a torsional stiffness of the whole shaft coupling.

In an aspect, an isolation device is provided for a belt and a component shaft in an engine. The device includes a hub, a pulley, an isolation spring and a damping member that is fixed rotationally relative to the hub and is engageable frictionally with the pulley. Torque transmission through the spring below a selected non-zero torque, irrespective of hub load on the pulley, drives a change in radius of the helical coils of the spring that is sufficiently small that the spring avoids pressing the damping member against the pulley. Torque transmission through the spring above the selected non-zero torque, irrespective of hub load on the pulley, drives a change in radius of the helical coils that is sufficiently large that the isolation spring applies a radial force to press the damping member against the pulley so as to generate frictional damping.

In an aspect, a power transfer device, such as a decoupler, is provided for transferring torque between a shaft and a belt. The device includes: a hub configured to couple to the shaft, a pulley rotatably coupled to the hub that includes a power transmitting surface configured to engage the belt, an isolation spring to transfer a rotational load from one of the pulley and the hub to the other of the pulley and the hub, optionally a one-way clutch to permit overrunning of one of the pulley and the hub relative to the other of the pulley and the hub in a first direction, and a damping member positioned to be driven into frictional engagement with a friction surface by a force from the isolation spring acting on the damping member that varies based on the rotational load transferred by the isolation spring.

A torsional vibration damper arrangement for a drive train of a motor vehicle includes a torsional vibration damper having an input flange, a first output flange, a second output flange, a hub, a first connecting element, and a second connecting element. The first output flange is rotatable relative to the input flange about an axis of rotation against a spring device. The first connecting element lies on a first radius relative to the axis of rotation and connects the first output flange, the second output flange, and the hub in rotationally fixed and form-fitting or force-fitting manner for torque transmission to a further component. The second connecting element is disposed at least partially radially inside the hub and connects the hub to the second output flange in a force-fitting or form-fitting manner.

A vibration isolating coupler including a first coupler portion, a second coupler portion including an external surface and an internal surface portion, and a vibration isolating portion extending between the first coupler portion and the second coupler portion. The vibration isolating portion including a first solid annular portion and a second solid annular portion. The vibration isolating portion including a plurality of slots extending from the first solid annular portion toward the second solid annular portion forming a plurality of vibration isolating elements. Each of the plurality of vibration isolating elements is disconnected from adjacent ones of the plurality of vibration isolating elements by a corresponding one of the plurality of slots. The plurality of vibration isolating elements enabling torsional rotation of the first coupler portion relative to the second coupler portion.

A torque converter, including: a cover; an impeller including an impeller shell connected to the cover and at least one impeller blade; a turbine in fluid communication with the impeder and including a turbine shell and at least one turbine blade; stator including at least one stator blade; and a vibration damper including a first cover plate, a second cover plate non-rotatably connected to the first cover plate, an intermediate flange axially disposed between the first cover plate and the second cover plate, at least one spring directly engaged with the first cover plate, the second cover plate, and the intermediate flange, and a resilient element directly engaged with the first cover plate and the intermediate flange and urging the intermediate flange in an axial direction, parallel to an axis of rotation of the torque converter, away from the first cover plate and into contact with the second cover plate.

A filtering pulley for an accessory drive of an internal combustion engine, having a hub suitable for connection to an engine accessory, an annular crown provided with a profile configured to cooperate with a drive belt, a coil spring able to transmit torque between the crown and the hub, a first carrier constrained to a first end of the spring and a second carrier constrained to a second end of the spring. The annular crown is externally coaxial to the hub and supported in a rotationally free manner on the hub, and each of the carriers is rotationally coupled to both the hub and the crown with a limited possibility of relative rotation with respect to each of them.

An actuator arrangement for applying a torque to a shaft of a machine, in particular a reciprocating piston engine, includes: a) at least one actuator device for applying the torque; and b) at least one rotatable seismic mass coupled to the shaft. The at least one actuator device is designed to apply the torque to the shaft between the seismic mass and the shaft. A corresponding method is provided for active damping of torsional vibrations of the shaft having the actuator arrangement.