Torsional vibration reducing apparatus

A torsional vibration reducing apparatus that comprises an input member for rotating and connecting to a driving side, an output member having a rotation central line with said input member and for rotating and connecting to a driven side, and an elastic body arranged in a circumferential direction between said input member and said output member;

• and reduces a rotational fluctuation based on an elastic deformation of said elastic body in said circumferential direction at a time of driving of said output member on said driven side by said input member of said driving side:
• wherein one of said input member and said output member comprises guide portions, arc-extending, which is faced to said elastic body from outside and has said rotation central line of said input member and said output member, another of said input member and said output member comprises a center supporting plate and overhang boards extending between said elastic body adjacent to said circumferential direction of said supporting plate and said elastic body, said respective guide portions form an engaging portion extended in diameter inside on both circumferential direction ends, and respective overhang boards form a pressurization section extended in diameter outside on said both circumferential direction ends;
• wherein said torsional vibration reducing apparatus further comprises supporting structures in an axial direction and a radial direction to said input member and/or said output member arranged in circumferential direction ends of said respective elastic bodies, and retainers being movable to said circumferential direction along said guide portions;
• said retainers have bottomed recesses for respectively containing opposite ends to said circumferential direction of said elastic bodies, and said retainers are opposed and arranged to said engaging portions adjacent to said guide portions and pressurization sections adjacent to said overhang boards in pressure receiving sections which are side ends separated from said bottomed recess in said circumferential direction;
• wherein said elastic body comprises a low-rigidity first elastic member, a high-rigidity second elastic member and an intermediate member for connecting said first elastic member and said second elastic member in series with regard to at least one end of said retainers, and said first elastic member, said intermediate member and side ends adjacent to intermediate member of said second elastic member are contained in said bottomed recesses of said corresponding retainers, and said intermediate member is slidably supported to an opposite surface in a radial direction of said bottomed recess of said retainers;
• and
• wherein in said retainers being a pair, said retainer located at an upstream in a torque transmission direction is circumferentially moved, by making contact with said pressurization section adjacent in said circumferential direction, along said guide portion toward said retainer located at a downstream in said torque transmission direction and engaged with said engaging portion adjacent to said guide portion, against a low elastic force based on a serial combination of an elastic modulus of said first elastic member and an elastic modulus of said second elastic member in a transmission torque range lower than a rated use, and against a high elastic force based on said high elastic modulus of said second elastic member alone in a rated transmission torque range.