Hst and transmission device

An HST comprising:

• a pump shaft;
• a pump main body supported by the pump shaft in a manner relatively non-rotatable around an axial line with respect to the pump shaft;
• a pump-side swash plate defining a capacity of the pump main body;
• a pump-side swash plate holder supporting a rear surface of the pump-side swash plate;
• a motor shaft;
• a motor main body supported by the motor shaft in a manner relatively non-rotatable around an axial line with respect to the motor shaft;
• a motor-side swash plate defining a capacity of the motor main body;
• a motor-side swash plate holder supporting a rear surface of the motor-side swash plate;
• a center section on which the pump main body and the motor main body directly or indirectly abut in a slidable manner around the respective axial lines and which is formed with oil paths fluidly connecting the pump main body and the motor main body;
• and
• a main plate and a sub-plate hold or support the center section, the pump-side swash plate holder and the motor-side swash plate holder in a sandwiched manner by inner surfaces of the main plate and the sub-plate that face each other, wherein
• the main plate is provided with an extended region that extends farther outward in a planar direction of the main plate than an installation space of the center section, the pump-side swash plate holder and the motor-side swash plate holder, and than the sub-plate as viewed along a direction in which the main plate and the sub-plate face each other.