Gear wheel that is provided with spokes (17) which extend between a rim (16) supporting a gear mesh (15) and a corresponding gear hub (18), whereby free spaces (19) are located between the spokes (17) which extend between the rim (16) and the gear hub (18), characterised in that at least one of said free spaces (19) is filled with a block (20) made of a rigid, incompressible material, whereby between the gear wheel (10) on the one hand and the block (20) on the other hand a viscoelastic material (21) is located.

A coupling device according to an embodiment is a coupling device for connecting a first shaft and a second shaft that includes a primary inner ring member mounted on the first shaft, a primary outer ring member disposed on an outer circumferential side of the primary inner ring member, a primary elastic member for connecting the primary inner ring member and the primary outer ring member, a secondary inner ring member mounted on the second shaft, a secondary outer ring member disposed on an outer circumferential side of the secondary inner ring member, a secondary elastic member for connecting the secondary inner ring member and the secondary outer ring member, and a weight attaching plate interposed between the primary outer ring member and the secondary outer ring member, the weight attaching plate including a weight attaching portion capable of attaching and detaching an additional weight to and from the outer circumferential side of the primary outer ring member and the outer circumferential side of the secondary outer ring member.

A dynamic damper assembly may include a plurality of bodies arranged at predetermined intervals on an outer peripheral surface of a drive shaft, and an elastic body formed to surround each of the bodies and fixing each body to the drive shaft.

A damper (10) includes a housing (11) and a rotor (16) combined with the housing (11) so as to be capable of rotating relative to the housing (11). The damper (10) includes an attenuating medium (90) filled in a rotation area inside the housing (11) wherein the rotor (16) rotates, and added with viscoelasticity by a viscoelasticity treatment; and an enclosure portion (80) provided outside the rotation area of the rotor (16), and communicating with the rotation area.

A vibration absorber for securely fixing to the housing of a gearbox includes an absorber mass having a first group of segments that are rotationally symmetrical to one another with respect to a rotational axis and/or central axis of the gearbox. The segments can be rigidly connected to one another. The vibration absorber can further include connectors that are rigidly connected to two segments each.

A vibration damping device for use with a downhole tool having a tool axis may comprise a device housing mechanically coupled to the downhole tool, wherein the device housing defines a receptacle having a volume and an inner surface; an inertia element movably supported in the receptacle and having a volume, a mass, and a non-zero moment of inertia about the tool axis; wherein the inertia element volume is greater than the receptacle volume and an interstitial volume is defined between the inertia element and the receptacle, and wherein the interstitial volume is occupied by a fluid or an elastomer. The device may include a longitudinal bearing and/or a radial bearing between the inertia element and the receptacle. The device may also include a pressure compensation device in fluid communication with the receptacle and positioned within or an integral part of the device housing.

A torsion absorber is provided for attachment to a cylindrical section of a shaft. The torsion absorber includes a flywheel and at least one tensioner. The at least one tensioner is configured to brace a first segment and a second segment of the flywheel against the cylindrical section of the shaft.

A centrifugal pendulum device for use in a drive train of a vehicle powered by an internal combustion engine includes at least one support flange rotatable about an axis of rotation to which pendulum masses are mounted thereon in a circumferential direction via a bifilar pendulum suspension. The pendulum masses are configured to perform a relative movement with respect to the support flange when a rotational irregularity occurs in the drivetrain under effects of centrifugal force in conjunction with cylindrical rollers which are guided in roller tracks of the support flange. The pendulum masses run in opposite directions to one another and thereby absorb vibrations. The support flange includes roller tracks which are open in a direction of the axis of rotation and all the cylindrical rollers are acted upon by force by a prestressing element radially in the direction of the roller tracks.

A vibration damping device for use with a downhole tool having a tool axis may comprise a device housing mechanically coupled to the downhole tool, wherein the device housing defines a receptacle having a volume and an inner surface; an inertia element movably supported in the receptacle and having a volume, a mass, and a non-zero moment of inertia about the tool axis; wherein the inertia element volume is greater than the receptacle volume and an interstitial volume is defined between the inertia element and the receptacle, and wherein the interstitial volume is occupied by a fluid or an elastomer. The device may include a longitudinal bearing and/or a radial bearing between the inertia element and the receptacle. The device may also include a pressure compensation device in fluid communication with the receptacle and positioned within or an integral part of the device housing.

A vibration damping device for use with a downhole tool having a tool axis may comprise a device housing mechanically coupled to the downhole tool, wherein the device housing defines a receptacle having a volume and an inner surface; an inertia element movably supported in the receptacle and having a volume, a mass, and a non-zero moment of inertia about the tool axis; wherein the inertia element volume is greater than the receptacle volume and an interstitial volume is defined between the inertia element and the receptacle, and wherein the interstitial volume is occupied by a fluid or an elastomer. The device may include a longitudinal bearing and/or a radial bearing between the inertia element and the receptacle. The device may also include a pressure compensation device in fluid communication with the receptacle and positioned within or an integral part of the device housing.