Power transmission device

A power transmission device comprising:

• a first rotating member configured to be rotated by power transmitted from a prime mover;
• a second rotating member configured to rotate relative to the first rotating member;
• a first engagement member configured to rotate integrally with the second rotating member at all times;
• a second engagement member configured to be pressed toward the first engagement member;
• and
• a moving member configured to
• rotate integrally with the first rotating member at all times,
• be separated from the first engagement member and the second engagement member at an initial position,
• mesh with the second engagement member to cause the second engagement member to rotate integrally with the first rotating member at a first preparation position where the moving member has moved in an axial direction of the first rotating member from the initial position by receiving an external force, and
• cause the second rotating member to rotate integrally with the first rotating member by meshing with the first engagement member and causing the first engagement member to rotate integrally with the first rotating member at a first switching position where the moving member has moved in the axial direction of the first rotating member from the first preparation position by receiving an external force.