Flywheel device for prime mover

A flywheel device for a prime mover, disposed between an output shaft of the prime mover and a driven shaft driven by the output shaft, for transmitting torque of the prime mover to the driven shaft, while reducing torque variation and torsional vibrations, comprising:

• a first rotary mass member provided on the output shaft;
• a second rotary mass member connected to the driven shaft;
• a spring mechanism connected between said first rotary mass member and said second rotary mass member, for damping torsional vibrations of the output shaft;
• and
• a damping mechanism disposed inward of said spring mechanism in a radial direction of the output shaft, and connected between said first rotary mass member and said second rotary mass member, for generating rotational resistance between said first rotary mass member and said second rotary mass member,
• wherein said damping mechanism includes:
• a cam member provided such that said cam member is movable in an axial direction along an axis of the output shaft;
• a holding member disposed in a manner opposed to said cam member in the axial direction;
• first and second friction members disposed between said cam member and said holding member, such that said first and second friction members are connected to said first rotary mass member and said second rotary mass member, respectively, and engaged with each other;
• a spring member urging said cam member toward said first and second friction members to thereby cause frictional forces to be generated between said first and second friction members due to pressing of said first and second friction member by said cam member;
• and
• a weight member held between said cam member and said holding member, such that as the rotational speed of the prime mover rises, said weight member causes said cam member to be moved in a direction away from said first and second friction members against the urging force of said spring member, to thereby reduce the frictional forces, wherein
• said first rotary mass member and said holding member have bolt insertion holes formed therethrough at respective locations corresponding to each other, and are mounted on the output shaft using common bolts inserted though the insertion holes.