Torque variation absorbing device

A torque variation absorbing device comprising:

• a driving member fixed to a drive shaft and having first and second driving plates which define windows therein and inner and outer rings, said outer ring being clamped between said first and second driving plates, said inner ring being fixed to said first driving plate;
• a driven member arranged coaxially with said driving member and rotatably supported via a bearing by said driving member so as to rotate relative to said driving member around a center of relative rotation between said driving and driven members;
• a driven disk arranged between and supported rotatably relative to said driving member and said driven member;
• and
• a torque limiting mechanism interposed between said driven disk and said driven member, a plurality of substantially identical damping mechanisms arranged on a common circle and interposed between said driving member and said driven disk, and a hysteresis mechanism interposed between said driving member and said driven member, said torque limiting mechanisms being located radially inside said damping mechanisms, each of said damping mechanisms including a coil spring with first and second ends and first and second seat members positioned at said first and second ends of said coil spring, respectively, each of said damping mechanisms being set at said windows defined in said driving plates such that said first and second seat members are in detachable contact with said driving member and such that an angular gap is provided in a circumferential direction of the torque variation absorbing device between at least one of said first and second seat members and said driven disk, said coil spring including a first coil spring portion close to said center of relative rotation and a second coil spring portion displaced from said center of relative rotation, each of said first and second seat member having a convex portion and being capable of inclining around an inclining center defined by a center of curvature of said convex portion, each of said first and second seat members being set at said windows of said driving member with an axis of each of the seat members set at an angle with respect to a line connecting centers of said first and second ends of said coil spring by pre-constructing a portion of said driving member defining an end of each of said windows to incline by said angle with respect to a plane perpendicular to the line connecting the centers of said first and second ends of said coil spring such that said first coil spring portion is set to be compressed more than said second coil spring portion.