Continuously variable powertrain device for work vehicle and work vehicle including the same

A continuously variable powertrain device, for a work vehicle, to transmit a motive power from an engine to a travel device, the continuously variable powertrain device comprising:

• a hydraulic static transmission to output a continuously shifted motive power while continuously varying a velocity of the motive power received from the engine;
• a planetary transmission to receive the motive power from the engine and the continuously shifted motive power and to output a compound motive power;
• a pressure detector to detect a hydraulic pressure in a closed circuit of the hydraulic static transmission;
• a planetary clutch mechanism to switch a shift level of the planetary transmission;
• and
• a powertrain controller to control actuation of the hydraulic static transmission and the planetary transmission based on a shift command, the powertrain controller being configured or programmed to function as:
• a continuously variable speed controller to generate a shift control signal to control adjustment of a ratio of the hydraulic static transmission;
• a planetary clutch controller to generate a clutch control signal to control switching of the shift level of the planetary transmission;
• and
• a switching timing changer to change, based on the velocity of the motive power transmitted to the travel device and on the hydraulic pressure detected by pressure detector, a switching timing of the shift level to be switched by the planetary clutch controller.