Drum type transmission

A drum type transmission including a transmission shaft having a plurality of shift gears, a drum member that is rotated about a drum shaft so that a shift operation is performed to a park position, a neutral position, or a transmission position, and a shift operation gear train for transmitting a drive force of an electric motor to the drum shaft, the drum type transmission comprising:

• a park pawl that is engaged with and disengaged from a park gear disposed on the transmission shaft in a relative rotation unavailable manner;
• a park pawl operation member that engages the park pawl with the park gear when the drum member is in the park position and disengages the park pawl from the park gear when the drum member is out of the park position;
• and
• an assist cam that assists a movement of the drum member in a direction in which the park pawl is disengaged from the park gear when the drum member is rotated from the park position toward the transmission position or the neutral position, or in a direction in which the park pawl is engaged with the park gear when the drum member is rotated from the transmission position or the neutral position toward the park position, wherein
• the assist cam is disposed at one end portion of an assist operation shaft which is rotated by power branched from the shift operation gear train.