Working vehicle and HST unit

A working vehicle comprising a vehicle frame, a driving power source supported by the vehicle frame, a pair of left and right first and second main driving wheels positioned on a rear side in a vehicle lengthwise direction, a hydrostatic transmission (“HST”), formed by a hydraulic pump main body which is operatively driven by the driving power source and a hydraulic motor main body which is fluidly connected to the hydraulic pump main body through a pair of first and second HST lines, and a differential gear device differentially outputting rotational power from the HST to the pair of main driving wheels, the working vehicle further comprising:

• an axle unit including the differential gear device, an axle case that accommodates the differential gear device, an axle input shaft that is supported by the axle case in a state where its first end extends outward from the axle case so as to input rotational power from the HST, and first and second main output shafts that are differentially driven to each other by the differential gear device and output rotational power toward the first and second main driving wheels;
• an HST unit including the hydraulic pump main body, the hydraulic motor main body, a capacity adjustment mechanism that changes a capacity of at least one of the hydraulic pump main body and the hydraulic motor main body, an HST case that that support the hydraulic pump main body and the hydraulic motor main body, respectively, in a relatively non-rotatable manner with respect thereto, an HST input shaft that is supported by the HST case in a state capable of being operatively coupled to the driving power source, and an HST output shaft that is supported by the HST case in a state where at least its first end is extended outward from the HST case so as to output rotational power of the hydraulic motor main body to the outside, wherein:
• the axle unit is directly or indirectly supported by the vehicle frame so as to be positioned close to the first main driving wheel on a first side in a vehicle width direction in a state where the axle unit is directly or indirectly supported by the vehicle frame, the axle input shaft is supported by the axle case in a rotatable manner around an axis line while extending along the vehicle width direction and having an end extended outward from the axle case, the end being positioned on an opposite side in the vehicle width direction with respect to the first side on which the first main driving wheel is positioned,
• the HST unit is directly or indirectly supported by the vehicle frame so as to be positioned forward of and away from the axle unit in a state where the HST output shaft extends in the vehicle widthwise direction,
• the HST output shaft is supported by the HST case in a rotatable manner around an axis line while having an end extended outward from the HST case, the end being closer to the first side in the vehicle width direction on which the first main driving wheel is positioned,
• the HST output shaft and the axle input shaft are operatively connected to each other through an endless type transmission member,
• the first and second main output shafts are positioned downward of the axle input shaft,
• the first main output shaft has an end, which is on a side closer to the corresponding first main driving wheel, extended outward from the axle case so as to be operatively connected to the first main driving wheel, and
• the second main output shaft is operatively connected to the second main driving wheel through a transmission shaft along the vehicle width direction so as to have a free space between the first and second main driving wheels and above the transmission shaft.