Working vehicle

1. A working vehicle comprising:

an engine mounted on a traveling machine body;

a hydraulic continuously variable transmission configured to shift driving force from the engine;

a transmission case incorporating the hydraulic continuously variable transmission; and

rear traveling units disposed on both left and right sides of the transmission case via rear axle cases,

wherein the transmission case is divided into three sections of a front case, an intermediate case, and a rear case,

wherein the rear axle cases on the left and right sides are attached to both left and right sides of the rear case,

wherein the intermediate case, coupling the front case to the rear case, is coupled to left and right vehicle body frames forming the traveling machine body, and

wherein end portions of the left and right vehicle body frames are coupled to both left and right side faces of the intermediate case by an upper vehicle body coupling shaft member and a lower vehicle body coupling shaft member.

2. The working vehicle according to claim 1 , wherein the intermediate case and the rear case are made of cast iron and the front case is made of die-cast aluminum.

3. The working vehicle according to claim 1 ,

wherein an input shaft that receives driving force from the engine and an input transmission shaft that receives driving force from the input shaft extend from the front case to the intermediate case, while being in parallel with each other, and

wherein the hydraulic continuously variable transmission is disposed in the front case via the input transmission shaft.

4. The working vehicle according to claim 3 , wherein a forward/backward traveling switching mechanism configured to switch an output from the hydraulic continuously variable transmission between normal and reverse rotation directions is disposed in the intermediate case.

5. The working vehicle according to claim 3 , wherein the hydraulic continuously variable transmission is attached on an inner surface side of a front lid member that is detachably attached to close an opening on a front surface of the front case.

6. The working vehicle according to claim 5 ,

wherein a traveling transmission gear mechanism configured to achieve multistage transmission of an output from the forward/backward traveling switching mechanism is further disposed in the front case, and

wherein the hydraulic continuously variable transmission is disposed at a higher position than the traveling transmission gear mechanism in the front case.

7. The working vehicle according to claim 1 ,

wherein a lubricant oil pump driven by the driving force from the engine is disposed in the transmission case, and

wherein hydraulic oil in the transmission case is supplied by the lubricant oil pump to an internal mechanism in the transmission case for lubrication.

8. The working vehicle according to claim 7 ,

wherein a front chamber, an intermediate chamber, and a rear chamber are formed in the transmission case, and

wherein the lubricant oil pump is supported by an intermediate supporting plate attached to a front surface side of a rear partitioning wall partitioning between the intermediate chamber and the rear chamber.

9. The working vehicle according to claim 1 ,

wherein a differential mechanism configured to transmit shifted driving force from the transmission case to the left and right rear traveling units is disposed in the transmission case, and

wherein a parking brake configured to maintain a braking state of the differential mechanism is disposed in the transmission case, separately from left and right brake mechanisms configured to put a brake on the rear traveling units.

10. The working vehicle according to claim 9 ,

wherein a front chamber, an intermediate chamber, and a rear chamber are formed in the transmission case,

wherein the parking brake is positioned on the intermediate chamber side,

wherein the differential mechanism is positioned on the rear chamber side,

wherein an intermediate supporting plate is detachably fastened to a front surface side of a rear partitioning wall partitioning between the intermediate chamber and the rear chamber, and

wherein the parking brake is supported by the intermediate supporting plate.

11. The working vehicle according to claim 9 , wherein a vehicle speed synchronized output is transmitted from a driving force transmission system for the parking brake to a PTO shaft extending rearward from the transmission case.