A vibration reduction device for reducing a torsional vibration from an engine includes an input rotary part, an output rotary part, a damper part, a dynamic vibration absorbing device, and a hysteresis torque generating part. The torsional vibration is input to the input rotary part. The output rotary part is disposed to be relatively rotatable with respect to the input rotary part. The damper part is disposed between the input rotary part and the output rotary part and attenuates the torsional vibration input to the input rotary part. The dynamic vibration absorbing device is for absorbing the torsional vibration output from the damper part. The hysteresis torque generating part is capable of generating a hysteresis torque when the damper part is in operation.

A damper apparatus includes: an input element; an output element; a first torque transfer path including an intermediate element, a first elastic body, and a second elastic body configured to transfer the torque between the intermediate and the output element; and a second torque transfer path including a third elastic body configured to transfer the torque between the input element and the output element. The intermediate element includes a first plate member including a torque transfer portion arranged so as to extend in a radial direction of the damper apparatus between the first and second elastic bodies and configured to support at least ends of the first and second elastic bodies from a radially outer side, and a second plate member coupled to a mass and including a coupling portion arranged between the first and second elastic bodies and fitted to the torque transfer portion of the first plate member.

First to fourth springs SP11 to SP22, two each of four types of springs, are disposed such that attachment radii r11 to r22, which are the distances from a central axis CA of a damper device to the axes of the respective first to fourth springs SP11 to SP22, are equal. Further, the first to fourth springs SP11 to SP22 are disposed such that the axes thereof are arranged in the same plane. With this arrangement, the four types of springs (first to fourth springs SP11 to SP22) can be compactly arranged, and the axial length of the damper device can be reduced.

A damper device includes a damper device body and a dynamic vibration absorber. The damper device body includes an input member and an output member, which are coupled to be rotatable relatively to each other. The dynamic vibration absorber is attached to the damper device body. The dynamic vibration absorber includes a mass body, a housing and a viscous fluid. The mass body is disposed to be rotatable relatively to the damper device body. The housing accommodates the mass body. The viscous fluid is filled in the housing.

The overall size of a damper device having two transmission paths is reduced. A damper device including an input element to which torque from an engine is transmitted and an output element includes: a first intermediate element; a second intermediate element; a first elastic body disposed between the input element and the first intermediate element; a second elastic body disposed between the first intermediate element and the output element; a third elastic body disposed between the input element and the second intermediate element; a fourth elastic body disposed between the second intermediate element and the output element; and a fifth elastic body disposed between the first intermediate element and the second intermediate element, wherein attachment radii of the first to fourth elastic bodies are equal.

A damper device that includes an input to which torque from an engine is transmitted; an output; a first intermediate element; a second intermediate element; a first transmission member that transmits torque between the input and the first intermediate element; a second transmission member that transmits torque between the first intermediate element and the output; a third transmission member that transmits torque between the input and the second intermediate element; a fourth transmission member that transmits torque between the second intermediate element and the output; and a fifth transmission member that transmits torque between the first intermediate element and the second intermediate element, wherein at least one of the first, second, third, fourth, and fifth transmission members has variable stiffness that tends to increase as a rotation speed of the damper device increases.

A torque fluctuation inhibiting device includes a mass body, a plurality of centrifugal elements, an actuation preventing mechanism and a cam mechanism. The mass body is rotatable with a rotor, and is rotatable relatively to the rotor. Each of the centrifugal elements is disposed to receive a centrifugal force to be generated by rotation of the rotor and the mass body, and is movable in a radial direction. The actuation preventing mechanism restricts at least one of the centrifugal elements from moving outward in the radial direction when the rotor or the mass body is rotated at a predetermined speed or greater. The cam mechanism converts the centrifugal force into a circumferential force with use of actuation of the plurality of centrifugal elements moved in the radial direction by the centrifugal force when a relative displacement is produced between the rotor and the mass body in a rotational direction.

A vibration damping device 20 includes: a crank member 22 that is swingable along with rotation of a driven member 15 to which torque from an engine EG is transferred; and an inertial mass body 23 coupled to the driven member 15 via the crank member 22 and swung about a center of rotation RC in conjunction with the crank member 22 along with rotation of the driven member 15. The vibration damping device 20 is designed such that an effective order q.sub.eff becomes higher as the amplitude of vibration of input torque transferred from the engine EG to the driven member 15 becomes larger.

A vibration damping device is provided with a first coupling shaft and a a second coupling shaft supported by one of a restoring force generation member and an inertial mass body to couple the restoring force generation member and the inertial mass body so that the restoring force generation member and the inertial mass body are rotatable relative to each other; and a guide portion formed in the other of the restoring force generation member and the inertial mass body to guide the second coupling shaft. The second coupling shaft swings about the first coupling shaft while keeping the interaxial distance between the shafts constant, and swings about a virtual axis, the relative position of which with respect to the inertial mass body is determined to be invariable, while keeping the interaxial distance between the virtual axis and the second coupling shaft constant.

A torque fluctuation inhibiting device includes a mass body, a plurality of centrifugal elements, an actuation preventing mechanism and a cam mechanism. The mass body is rotatable with a rotor, and is rotatable relatively to the rotor. Each of the centrifugal elements is disposed to receive a centrifugal force to be generated by rotation of the rotor and the mass body, and is movable in a radial direction. The actuation preventing mechanism restricts at least one of the centrifugal elements from moving outward in the radial direction when the rotor or the mass body is rotated at a predetermined speed or greater. The cam mechanism converts the centrifugal force into a circumferential force with use of actuation of the plurality of centrifugal elements moved in the radial direction by the centrifugal force when a relative displacement is produced between the rotor and the mass body in a rotational direction.