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.

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.

Pulley assembly (111) comprising a hollow shaft (112) with an axis X, the hollow shaft (112) being suitable for being mounted on a shaft of a rotating electrical machine, the hollow shaft comprising at least one thread or tapping (132, 133) and a collar (113) extending radially outwards, wherein said hollow shaft also includes: a nut (128, 129) screwed on the hollow shaft via the thread or tapping; a spring (126) mounted about a portion of the nut; at least one ball bearing (122, 123) tightly fitted to the hollow shaft; a pulley (130), tightly fitted to said at least one bearing, about the spring, the nut and the hollow shaft. The nut (128, 129) includes a radial shoulder (131) mounted between the spring (126, 127) and the ball bearing (122, 123), the spring being held axially between the collar (113) and the radial shoulder (131).

Provided is an actuator that has a simple configuration and can stably achieve high output. This actuator has: a movable body provided with a cylindrical magnet section alternately having N-pole faces and S-pole faces on a peripheral surface thereof along the circumferential direction; a fixed body provided with pole tooth surfaces disposed facing the peripheral surface a magnet section and a coil that excites the pole tooth sections; and a spring material holds the movable body to the fixed body in a freely movable manner. The spring material is fixed to at least one of the movable body and the fixed body via a joint section. The joint section has a fixing part for fixing and end section of the spring material, and a stress relaxation part that is disposed in proximity to the fixing part and relaxes stress generated during deformation of the spring material.

A torsional vibration damper that a torsional vibration damper having a planetary gear unit, and a manufacturing method of the torsional vibration damper for limiting damages on gears of the planetary gear unit due to dimension errors. In the planetary gear unit, at least one of a sun gear, a ring gear, and a set of planetary gears is/are formed by a press forming method. The gear formed by the press forming method is engaged with the remaining gears in such a manner that a thinner portion of each tooth is individually engaged with a thicker portion of the adjacent teeth of the remaining gears.

There is provided a translational inerter assembly for damping movement of a flight control surface of an aircraft with a support structure. The translational inerter assembly includes a press fit element rotatably disposed within the flight control surface. The translational inerter assembly further includes an inertia element disposed in the press fit element. The translational inerter assembly further includes a torsion bar coupled to the inertia element and to the support structure of the aircraft, such that when the flight control surface rotates, the inertia element translates, and movement of the flight control surface is dampened.

In an aspect, an isolator is provided for isolating a device driven by an engine via an endless drive member. The isolator includes a shaft adapter that is connectable with a shaft of the device and that defines an isolator axis, a rotary drive member that is engageable with the endless drive member, a first isolation spring arrangement that includes a first torsion spring, and that is positioned to transfer torque between the shaft adapter and an intermediate drive member, and a second isolation spring arrangement that is positioned to transfer torque between the intermediate member and the rotary drive member.

A torsional vibration damper whose vibration damping performance will not be reduced in a high speed range. In the torsional vibration damper, a planetary gear is oscillated within a first oscillating range when a torsional torque is smaller than a reference torque, and within a second oscillating range when the torsional torque is greater than the reference torque. Each backlash between the pinion gear and at least one of a sun gear and a ring gear within the second oscillating range is individually wider than each backlash between the pinion gear and the sun gear and each backlash between the pinion gear and the ring gear within the first oscillating range.

An isolator comprising a shaft, a pulley journalled to the shaft, a first torsion spring engaged between the shaft and the pulley, a second torsion spring engaged between the shaft and the pulley, the first torsion spring and the second torsion spring wound in opposite directions, the first torsion spring engaged to transmit a first torque in a first direction from the pulley to the shaft, the second torsion spring having a passive engagement with the pulley during transmission of the first torque, and the second torsion spring engaged to transmit a second torque in a second direction from the shaft to the pulley, the first torsion spring having a passive engagement with the pulley during transmission of the second torque.