An automatic transmission includes a mechanical oil pump, an electric oil pump, and a controller. The controller calculates a flow rate of oil necessary for the automatic transmission during the vehicle travels, and drives the electric oil pump when the calculated flow rate of the oil necessary for the automatic transmission is higher than a margin flow rate of the mechanical oil pump generated in a state where a hydraulic pressure necessary for the automatic transmission is ensured.

An automatic transmission includes a mechanical oil pump, an electric oil pump, and a controller. The controller calculates a flow rate of oil necessary for the automatic transmission during the vehicle travels, and drives the electric oil pump when the calculated flow rate of the oil necessary for the automatic transmission is higher than a margin flow rate of the mechanical oil pump generated in a state where a hydraulic pressure necessary for the automatic transmission is ensured.

A transmission device including a body, an input member extending along the body, and having a rotational axis, a gear assembly connected to the input member, having an inner gear, one or more intermediate gears engaged with the inner gear; and an outer gear engaged with one or more intermediate gears, wherein in a first position the gear assembly is configured to rotate at substantially the same rate as the input member and axial movement of at least one component to a second position, in a direction substantially parallel to the axis of rotation, allows the gear assembly to provide to an output member a different output rate relative to the input member, and an actuator movable between a first position at which the gear assembly moves to its first position and a second position at which the gear assembly moves to its second position, the actuator moves under hydraulic pressure.

Provided is a work vehicle capable of attaining a maximum vehicle speed specification value set in advance for each vehicle body even in the case where a device constituting an HST traveling drive system has deteriorated over time. In a wheel loader 1 equipped with an HST traveling drive system, a controller 5 is configured to, in the case where a detection pressure value P is equal to or less than a switching pressure value Ps corresponding to a switching point in the HST motor 42 between a maximum displacement volume qmax and a minimum displacement volume qmin, and a detection vehicle speed value V is less than an upper limit vehicle speed specification value Vmaxs, limit the minimum displacement volume qmin of the HST motor 42 to a first minimum displacement volume value qmin1 less than a minimum displacement volume specification value qmins that is associated with the upper limit vehicle speed specification value Vmaxs.

Provided is a work vehicle capable of attaining a maximum vehicle speed specification value set in advance for each vehicle body even in the case where a device constituting an HST traveling drive system has deteriorated over time. In a wheel loader 1 equipped with an HST traveling drive system, a controller 5 is configured to, in the case where a detection pressure value P is equal to or less than a switching pressure value Ps corresponding to a switching point in the HST motor 42 between a maximum displacement volume qmax and a minimum displacement volume qmin, and a detection vehicle speed value V is less than an upper limit vehicle speed specification value Vmaxs, limit the minimum displacement volume qmin of the HST motor 42 to a first minimum displacement volume value qmin1 less than a minimum displacement volume specification value qmins that is associated with the upper limit vehicle speed specification value Vmaxs.

An automatic transmission includes a mechanical oil pump, an electric oil pump, and a controller. The controller calculates a flow rate of oil necessary for the automatic transmission during the vehicle travels, and drives the electric oil pump when the calculated flow rate of the oil necessary for the automatic transmission is higher than a margin flow rate of the mechanical oil pump generated in a state where a hydraulic pressure necessary for the automatic transmission is ensured.