Power transmission system of hydraulically driven working vehicle

A power transmission system of a hydraulically driven working vehicle, comprising:

• a prime mover supported by a vehicle frame, the prime mover including a prime mover output shaft projecting in the fore-and-aft horizontal direction of the vehicle;
• a pump housing;
• a hydraulic pump disposed in the pump housing, the hydraulic pump including a pump shaft projecting from the pump housing in the fore-and-aft horizontal direction of the vehicle so as to be drivingly connected to the prime mover output shaft;
• a first hydraulic motor disposed outside the pump housing so as to be fluidly connected to the hydraulic pump;
• a first transaxle supported by one of front and rear portions of the vehicle frame, the first transaxle including a first transaxle housing, a pair of first axles disposed in the first transaxle housing so as to be driven by the first hydraulic motor, and a first differential gear unit disposed in the first transaxle housing so as to be drivingly interposed between the first hydraulic motor and the pair of first axles;
• a first power take off shaft (a first PTO shaft);
• and
• a working power train extracting a part of power transmitted from the prime mover output shaft to the pump shaft and transmitting the extracted power to the first PTO shaft, wherein the working power train includes a belt transmission, and wherein the belt transmission includes a drive shaft projecting in the fore-and-aft horizontal direction of the vehicle, and a belt interposed between the drive shaft and the pump shaft.