A vibration absorber which, in addition to a main mass which is fixed thereto and moved along a curved trajectory by a driving mechanism, comprises a substantially smaller variably adjustable rotating flywheel mass which is moved together with the main mass along the trajectory thereof, enabling the adjustment of the frequency of the absorber. The rotating flywheel mass is driven by a novel belt device independently of the driving mechanism. A rotating vibration absorber which, along with the main mass and the rotating flywheel mass, comprises its own damping unit, such as an eddy-current damping unit.

A vibration absorber which, in addition to a main mass which is fixed thereto and moved along a curved trajectory by a driving mechanism, comprises a substantially smaller variably adjustable rotating flywheel mass which is moved together with the main mass along the trajectory thereof, enabling the adjustment of the frequency of the absorber. The rotating flywheel mass is driven by a novel belt device independently of the driving mechanism. A rotating vibration absorber which, along with the main mass and the rotating flywheel mass, comprises its own damping unit, such as an eddy-current damping unit.

A vehicle powertrain variable vibration absorber assembly can be equipped in a hybrid electric vehicle (HEV). The vehicle powertrain variable vibration absorber assembly includes a rotary device, a drive-ratio assembly, and a spring. The rotary device, in an example, is a motor-generator unit (MGU). The drive-ratio assembly, in an example, is a planetary gear assembly. The drive-ratio assembly receives rotational drive input from the rotary device, and transmits rotational drive output to a powertrain component. The spring, in an example, is a variable stiffness spring. The spring is connected to the drive-ratio assembly and is connected to a grounded component. During use, the vehicle powertrain variable vibration absorber assembly absorbs different frequencies of vibration brought about by a vehicle engine amid different operating modes. The operating modes can involve cylinder deactivation technologies.

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.

A vibration suppression device that suppresses vibration of an operation unit in a mechanical system having a natural vibration mode including the operation unit, an actuator unit that operates the operation unit, and an elastic body that couples the operation unit and the actuator unit, the vibration suppression device including a generation means for generating a drive signal for driving the actuator unit, an estimation means for estimating a measurement amount related to the mechanical system, a correction means for correcting the drive signal generated by the generation means on the basis of the measurement amount estimated by the estimation means, and a change means for changing a gain used by the estimation means so that an influence of an increase in a modeling error becomes small in a period in which the modeling error of the mechanical system increases.

A vibration suppression device that suppresses vibration of an operation unit in a mechanical system having a natural vibration mode including the operation unit, an actuator unit that operates the operation unit, and an elastic body that couples the operation unit and the actuator unit, the vibration suppression device including a generation means for generating a drive signal for driving the actuator unit, an estimation means for estimating a measurement amount related to the mechanical system, a correction means for correcting the drive signal generated by the generation means on the basis of the measurement amount estimated by the estimation means, and a change means for changing a gain used by the estimation means so that an influence of an increase in a modeling error becomes small in a period in which the modeling error of the mechanical system increases.

A rotary damper assembly comprises a housing extending along a center axis. The housing includes an upper portion and a lower portion. The lower portion defines a fluid chamber. The upper portion defines a compartment in communication with the fluid chamber. The magnetic field generator includes a magnetic core located between the upper portion and the lower portion. The magnetic core extends along the center axis between the upper portion and the lower portion. At least one coil extends about the magnetic core. A shaft extends along the center axis through the upper portion and the magnetic core and into the fluid chamber to facilitate magnetorheological fluid flow from the compartment to the fluid chamber. The magnetic field generator includes an insert, containing a permanent magnetic material, for generating a permanent magnetic field to change viscosity of the magnetorheological fluid.

A rotary damper assembly comprises a housing extending along a center axis. The housing includes an upper portion and a lower portion. The lower portion defines a fluid chamber. The upper portion defines a compartment in communication with the fluid chamber. The magnetic field generator includes a magnetic core located between the upper portion and the lower portion. The magnetic core extends along the center axis between the upper portion and the lower portion. At least one coil extends about the magnetic core. A shaft extends along the center axis through the upper portion and the magnetic core and into the fluid chamber to facilitate magnetorheological fluid flow from the compartment to the fluid chamber. The magnetic field generator includes an insert, containing a permanent magnetic material, for generating a permanent magnetic field to change viscosity of the magnetorheological fluid.