Power transmission device

A power transmission device, comprising:

• an inertia ring having an annular shape, the inertia ring including a plurality of through holes extending through the inertia ring and disposed at intervals in a circumferential direction;
• a plate disposed on a first side with respect to the inertia ring in an axial direction;
• a plurality of first bolts screwed into the plurality of through holes from the first side to fasten the plate to the inertia ring;
• a torque transmission member to which a torque is transmitted from the inertia ring, the torque transmission member disposed on a second side with respect to the inertia ring in the axial direction;
• a plurality of second bolts screwed into the plurality of through holes from the second side to fasten the torque transmission member to the inertia ring, with each of the second bolts being screwed into a through hole into which one of the first bolts is screwed from the first side;
• and
• a knock pin configured to position the torque transmission member with respect to the inertia ring, wherein
• the plurality of through holes include first and second through holes,
• each first through hole includes a female threaded portion provided on an entirety thereof in the axial direction,
• each second through hole includes a first hole portion and a second hole portion, the first hole portion disposed on the first side in the axial direction, the first hole portion including a female threaded portion, the second hole portion disposed on the second side in the axial direction, the second hole portion including no female threaded portion,
• each first bolt is screwed into either one of the first through holes from the first side or the first hole portion of one of the second through holes from the first side,
• each second bolt is screwed into one of the first through holes from the second side, and
• the knock pin is inserted into the second hole portion of one of the second through holes from the second side, with one of the first bolts being screwed into the first hole portion of the same second through hole from the first side.