Vibration damping device and power transmission device

Abstract

A vibration damping device is equipped with a mass body disposed spaced apart from a rotational center axis of a rotary shaft by a certain distance, and a rolling bearing that rotatably supports the mass body with respect to the rotary shaft and holds a support posture of the mass body with respect to the rotational center axis of the rotary shaft constant.

1 . A vibration damping device comprising:
 a mass body disposed spaced apart from a center axis of a rotary shaft by a certain distance; and   support portion that rotatably supports the mass body with respect to the rotary shaft and holds a posture of the mass body with respect to the center axis of the rotary shaft constant so that an inertial force of the mass body in a translational direction other than a direction of the rotation acts on the rotary shaft, wherein   the support portion is constituted by a bearing provided between the rotary shaft and the mass body,   the bearing is constituted by a plurality of rolling members each of which is rollably supported on an outer periphery side of the rotary shaft and rollably engaged with the mass body, and   the plurality of the rolling members is a plurality of rows of radial ball bearings.   
     
     
         2 . A vibration damping device comprising:
 a mass body disposed spaced apart from a center axis of a rotary shaft by a certain distance; and   support portion that rotatably supports the mass body with respect to the rotary shaft and holds a posture of the mass body with respect to the center axis of the rotary shaft constant so that an inertial force of the mass body in a translational direction other than a direction of the rotation acts on the rotary shaft, wherein   the support portion is constituted by a slide bearing provided between the rotary shaft and the mass body, and the bearing has a cylindrical slide bearing face that surrounds the rotary shaft in parallel to the center axis of the rotary shaft.   
     
     
         3 . The vibration damping device according to  claim 1 , wherein the mass body is annularly formed so as to surround the rotary shaft. 
     
     
         4 . The vibration damping device according to  claim 2 , wherein the mass body is annularly formed so as to surround the rotary shaft. 
     
     
         5 . The vibration damping device according to  claim 3 , wherein the support portion retains the mass body in such a state that the mass body has the same center axis as the rotary shaft. 
     
     
         6 . The vibration damping device according to  claim 4 , wherein the support portion retains the mass body in such a state that the mass body has the same center axis as the rotary shaft. 
     
     
         7 . The vibration damping device according to  claim 1 , wherein the mass body has a center of gravity on the center axis of the rotary shaft. 
     
     
         8 . The vibration damping device according to  claim 2 , wherein the mass body has a center of gravity on the center axis of the rotary shaft. 
     
     
         9 . The vibration damping device according to  claim 1 , wherein the mass body has a center of gravity off the center axis of the rotary shaft. 
     
     
         10 . The vibration damping device according to  claim 2 , wherein the mass body has a center of gravity off the center axis of the rotary shaft. 
     
     
         11 . A power transmission device comprising:
 the vibration damping device according to  claim 1 ;   a case;   a driving-side gear shaft which functions as the rotary shaft and is rotatably supported in the case, and into which a rotational power is input;   a driven-side gear shaft which is accommodated in the case, meshes with the driving-side gear shaft, and rotates in a decelerative manner; and   an output shaft rotationally driven by the driven-side gear shaft.   
     
     
         12 . A power transmission device comprising:
 the vibration damping device according to  claim 2 ;   a case;   a driving-side gear shaft which functions as the rotary shaft and is rotatably supported in the case, and into which a rotational power is input;   a driven-side gear shaft which is accommodated in the case, meshes with the driving-side gear shaft, and rotates in a decelerative manner; and   an output shaft rotationally driven by the driven-side gear shaft.