Torque transmission device

A torque transmission device comprising:

• end joints each comprising a shaft shape and configured to transmit torque from one side to an other side;
• serrated portions each formed on an outer circumferential surface of a corresponding one of the end joints at an end of the end joint;
• a cylindrical member fitted to a region of each of the serrated portions at an inner circumferential surface of the cylindrical member;
• connection members each comprising a cylindrical shape and connecting a corresponding one of the end joints to the cylindrical member, each of the connection members comprising:
• a larger diameter portion fitted to an outer circumferential surface of the cylindrical member at an end of the cylindrical member;
• and
• a smaller diameter portion fitted to a corresponding one of the serrated portions, the smaller diameter portion comprising an end surface comprising at least one hollow portion, the hollow portion being constituted by a hollow formed in the end surface in an axial direction, the hollow portion allowing a clearance to communicate with an exterior of the connection member, the clearance being provided between the serrated portion and the smaller diameter portion;
• lock members each disposed at a position adjacent to the serrated portion in a corresponding one of the end joints so as to abut and lock the end surface of the smaller diameter portion of a corresponding one of the connection members.