Power transmission apparatus

A power transmission apparatus comprising:

• a first meshing engagement mechanism that selectively couples a first rotational section and a second rotational section;
• and
• a second meshing engagement mechanism that selectively couples a third rotational section and a fourth rotational section, wherein:
• the first rotational section has a cylindrical shape;
• the second rotational section is disposed concentrically with the first rotational section and has a cylindrical shape having a diameter larger than a diameter of the first rotational section;
• the third rotational section is disposed concentrically with the second rotational section and has a cylindrical shape having a diameter larger than the diameter of the second rotational section;
• the fourth rotational section is disposed concentrically with the third rotational section and has a cylindrical shape having a diameter larger than the diameter of the third rotational section;
• first meshing teeth are provided on one of the first rotational section and the second rotational section;
• second meshing teeth are provided on one of the third rotational section and the fourth rotational section;
• the first meshing engagement mechanism includes a first movable member having a cylindrical shape, the first movable member is provided between the first rotational section and the second rotational section so as to be movable in a direction of a rotational axis of the first rotational section, and the first movable member is provided with third meshing teeth that mesh with the first meshing teeth at a time when the first movable member moves in the direction of the rotational axis,
• the second meshing engagement mechanism includes a second movable member having a cylindrical shape, the second movable member is provided between the third rotational section and the fourth rotational section so as to be movable in the direction of the rotational axis, and the second movable member is provided with fourth meshing teeth that mesh with the second meshing teeth at a time when the second movable member moves in the direction of the rotational axis;
• and
• at least a portion of a first movable region along the direction of the rotational axis and at least a portion of a second movable region along the direction of the rotational axis overlap with each other in a radial direction with respect to the rotational axis, the first movable region being a region where the third meshing teeth are movable due to movement of the first movable member, and the second movable region being a region where the fourth meshing teeth are movable due to movement of the second movable member.