The present device includes a mass body, a centrifugal element and a plurality of conversion mechanisms. The mass body is disposed to be rotatable with the rotor and be rotatable relative to the rotor. The centrifugal element is disposed to receive a centrifugal force to be generated by rotation of at least one of the rotor and the mass body. Each of the plurality of conversion mechanisms is configured to convert the centrifugal force into a circumferential force when a relative displacement is produced between the rotor and the mass body in a rotational direction. The circumferential force is directed to reduce the relative displacement. The respective plurality of conversion mechanisms are disposed at intervals in a circumferential direction.

A damper device according to one embodiment, for example, includes: a rotating member that is rotatable about a rotational axis, the rotating member including a base portion that is plate-like and support portions that is attached to the base portion and extends in an axial direction of the rotational center; and a plurality of weight members disposed partially overlapping each other in the axial direction, the weight members being provided with tracks in respective overlapped parts of the weight members, the tracks guiding the support portion to be swingable with respect to the rotating member, wherein the support portion is shared in the tracks provided in the weight members.

The present device includes an inertia ring, a plurality of centrifugal elements, a plurality of cam mechanisms and a plurality of restriction mechanisms. The inertia ring is disposed to be rotatable with a hub flange and be rotatable relatively to the hub flange. Each centrifugal element is disposed to receive a centrifugal force generated by rotation of the hub flange and the inertia ring. When a relative displacement is produced between the hub flange and the inertia ring in a rotational direction while the centrifugal force is acting on each centrifugal element, each cam mechanism converts the centrifugal force into a circumferential force directed to reduce the relative displacement. Each restriction mechanism allows actuation of each centrifugal element by each cam mechanism, and restricts radial movement of each centrifugal element.

A torsional vibration damper in which a vibration damping performance is enhanced without increasing a manufacturing cost. A torsional vibration damper damps torsional vibrations by a relative rotation between a rotary member and an inertia body. Hardness of the contact surface of any one of the inertia body and a rolling mass is harder than the contact surface of the other one. Smoothness of the contact surface of any one of the inertia body and the rolling mass is smoother than the contact surface of the other one.

A torsional vibration damper that can be arranged in a fluid coupling to downsize a powertrain is provided. The torsional vibration damper has a mass body held in a rotary member in such a manner to be oscillated by torque pulse of the rotary member. The rotary member is arranged in an internal space of a fluid coupling in which a pump impeller, a turbine runner and a predetermined stationary member are held in a casing. A planetary unit that performs a differential action among three rotary elements is arranged in the casing. In the planetary unit, a first rotary element is connected to the stationary member, a second rotary element is connected to the rotary member, and a third rotary element is connected to the turbine runner.

A damper device includes a damper device body, an output shaft and a dynamic vibration absorber. The damper device body includes an input member and an output member. The input member and the output member are coupled to be rotatable relative to each other. The output shaft outputs a torque transmitted to it from the damper device body. The dynamic vibration absorber is attached to the output shaft.

A torsional vibration damper having an improved attenuation performance of low frequency vibration. The torsional vibration damper comprises a rotary member rotated by torque, an inertia body rotated relatively on an outer radial side of the rotary member due to torque pulse, and a rolling member coupled to the rotary member and the inertia body. The rotary member includes support sections that are provided on its outer radial side, and by which the rolling member is restricted in a rotating direction of the rotary member and is engaged movably in a radial direction of the rotary member. The inertia body includes: a pair of mass sections respectively projecting toward both sides in an axial direction; and a pair of raceway surfaces on which the rolling member rolls. A center of curvature of each raceway surface is deviated from a rotational center of the rotary member.

A bumper clip having rubber or elastomeric bumpers for use with a pendulum assembly for attachment to the crankshaft of an internal combustion engine is disclosed. The bumper clip is has particular application for use with pendulum carriers that are formed from stamped steel. By using the stamped steel carrier, more room is created to provide a more robust bumper. The pendulum carrier bumper clip can be either two separate, L-shaped clips or a single U-shaped clip. If the pendulum carrier bumper clip includes two separate clips, each clip includes a bumper surface to which the bumper is attached and an attachment leg for attachment of the clip to the pendulum carrier and to the crankshaft by a fastener such as a bolt. The bumper surface has a channel through which the pendulum carrier passes, thus dividing the bumper surface into two surfaces. A bumper is attached to each surface.

A pump system may include a pump, a driveshaft, driving equipment, and a vibration dampening assembly configured to reduce pump-imposed high frequency/low amplitude and low frequency/high amplitude torsional vibrations. The pump may have an input shaft connected to the driveshaft. The driving equipment may include an output shaft having an output flange connected to the driveshaft. The driving equipment may be configured to rotate the driveshaft to rotate the input shaft of the pump therewith. The vibration dampening assembly may include one or more flywheels operably connected to the input shaft and configured to rotate therewith.

An image forming apparatus includes: a plurality of stations and a plurality of stays arranged along a first direction; and a first board support member supporting a first electric board. Each of the plurality of stations includes: a rotation shaft extending in a second direction intersecting the first direction; and a photosensitive member and a flywheel provided to the rotation shaft. The first board support member is attached to two of the plurality of stays so as to bridge a gap between the two stays, and provided, in the second direction, on a first side opposite to a second side of the flywheel on which the photosensitive member is provided. The first board support member overlaps with the flywheel of at least one of the plurality of stations when viewed from a viewpoint along the second direction.