Shift Power Transmission Apparatus of a Tractor and Tractor

A shift power transmission apparatus of a tractor, the apparatus comprising:

• a hydrostatic continuously variable transmission unit that includes a hydraulic pump and a hydraulic motor, and is configured to receive motive power of an engine and output motive power of stepless rotational speed by changing a speed of the received motive power;
• a combined planetary power transmission unit that is configured to receive speed-changed output of the continuously variable transmission unit and motive power of the engine that is not subjected to speed change action by the continuously variable transmission unit, and combine the received speed-changed output and the motive power of the engine, and output combined motive power;
• and
• a shift output unit that includes a plurality of stage clutches and a shift output shaft that supports the plurality of stage clutches in a state of being arranged in a vehicle front-rear direction, the shift output unit being configured to receive the combined motive power from the combined planetary power transmission unit, and divide a speed range of the received combined motive power into a plurality of stages, and output the received combined motive power from the shift output shaft toward a travel apparatus,
• wherein the continuously variable transmission unit is provided in a state where the continuously variable transmission unit is located further toward a vehicle rear side than the engine, the continuously variable transmission unit having a motor shaft and a pump shaft that extend in the vehicle front-rear direction,
• the combined planetary power transmission unit is provided in a state where the combined planetary power transmission unit is located further toward the vehicle rear side than the engine, the combined planetary power transmission unit having a single planetary unit input axis and a single planetary unit output axis, the planetary unit input axis extending in a direction along the vehicle front-rear direction and parallel to the motor shaft and the pump shaft,
• the shift output unit is provided in a state where the shift output unit is located further toward the vehicle rear side than the combined planetary power transmission unit is, the shift output unit having a single shift unit input axis that extends coaxial with the planetary unit output axis,
• the apparatus further comprises a power transmission unit that is configured to transmit the motive power of the engine to the continuously variable transmission unit and the combined planetary power transmission unit, the power transmission unit including a rotary power transmission shaft, a pump transmission unit and a planetary transmission unit, the rotary power transmission shaft being located further toward the vehicle rear side than the engine a state of being interlockingly joined to an output shaft of the engine, the rotary power transmission shaft extending in a direction along the vehicle front-rear direction and parallel to the motor shaft and the pump shaft, the pump transmission unit being configured to input motive power of the rotary power transmission shaft to the pump shaft, and the planetary transmission unit being configured to input motive power of the rotary power transmission shaft to the combined planetary power transmission unit, and
• the continuously variable transmission unit is located at the same position as at least one of the combined planetary power transmission unit and the shift output unit in the vehicle front-rear direction.