Power transmission apparatus

A power transmission apparatus including a transmission, a case that accommodates the transmission, a counter drive gear to which power from the transmission is transmitted, a counter driven gear that meshes with the counter drive gear, and a drive pinion gear that is disposed and spaced apart in an axial direction from the counter driven gear and that rotates together with the counter driven gear, the power transmission apparatus comprising:

• a brake including a brake drum fixed to the case, a brake hub disposed inside of the brake drum and coupled to any rotational element of the transmission, a first friction engagement plate fitted to the brake hub, a second friction engagement plate fitted to the brake drum, a piston that is disposed inside of the brake drum and that presses and engages the first and second friction engagement plates by friction, and an engagement oil chamber defined inside of the brake drum and the piston and to which hydraulic oil is supplied,
• wherein the brake drum is fixed to the case so that a drum portion of the brake drum is disposed between the counter driven gear and the drive pinion gear in the axial direction,
• wherein the drum portion has an inner radial surface in which the second friction engagement plate is fitted and an outer radial surface opposite the inner radial surface, and
• wherein an axial end of the outer radial surface is adjacent to a tooth tip of the drive pinion gear and the axial end of the outer radial surface is disposed closer to an axis center of the counter driven gear and the drive pinion gear than an outer radial surface of the tooth tip.