In one embodiment, a method for cooling an engine damper, including converting a gas to a liquid, and cooling an engine damper by passing the liquid through a tube portion located between fan air flow and the engine damper.

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.

A power transmission device includes an inertia ring, a plate, a plurality of first bolts, a torque transmission member, and a plurality of second bolts. The inertia ring has an annular shape. The inertia ring includes a plurality of through holes. The plurality of through holes are disposed at intervals in a circumferential direction. The plate is disposed on a first side with respect to the inertia ring in an axial direction. The plurality of first bolts are screwed into the plurality of through holes from the first side to fasten the plate to the inertia ring. The torque transmission member is disposed on a second side with respect to the inertia ring in the axial direction. The plurality of second bolts are screwed into the plurality of through holes from the second side to fasten the torque transmission member to the inertia ring.

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 tool called a spinner is interposed between a rotary driver and a flexible shaft that is being rotated and moved axially when a duct or chimney is being cleaned by a whip head at the end of the shaft. A tubular shape collar has a home position on the body of the spinner. Grasping and holding the collar at its home position, while the driver rotates, helps steady the driver as the body moves within the collar. To dampen oscillation of the shaft, the collar is moved lengthwise from the body, and along the shaft to a working position where it is held manually. The collar is retained on the body by frictional means. A user can overcome the retaining force and, without using a second tool, slide the collar off the body and along the shaft to the working position, while the spinner is rotating or stationary.

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.

A damper for a torque converter is disclosed. The damper includes an outer spring and an inner spring coaxial with the outer spring; and a retaining plate to retain the outer spring and the inner spring. The retaining plate includes an upper spring guide, a lower spring guide, an outer spring support, and an inner spring support, wherein the upper spring guide extends substantially around an outer periphery of the retaining plate, the lower spring guide extends around an inner periphery of the retaining plate, the outer spring support directly contacts axial ends of the outer spring and the inner spring, and the inner spring support directly contacts the axial ends of the outer spring and the inner spring.

A magnetically-coupled torque assist apparatus includes a movable (rotor) magnet configured to rotate about a rotor magnet axis extending through the rotor magnet, and a stationary (stator) magnet. The rotor magnet and the stator magnet have a gap therebetween. There is an equilibrium state position (ESP) of the rotor magnet where forces acting on the rotor magnet are balanced such that the rotor magnet is stationary about the rotor magnet axis. And when the rotor magnet is rotated from the equilibrium state position (ESP) to an elastically stressed state position (SSP), magnetic fields of the rotor magnet and the stator magnet generate a resultant magnetic force on the movable magnet that biases the movable magnet towards the equilibrium state position. In some embodiments, the stator and rotor magnets are configured to create a Halbach-effect magnetic field bloom, which contributes to the magnetic forces.

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.