Transmission apparatus

A transmission apparatus comprising:

• an electrically-controlled hydrostatic transmission that changes rotary power of an engine steplessly and outputs the changed power, the hydrostatic transmission outputting predetermined rotary power at least in an uncontrolled state;
• a planetary gear mechanism that combines the rotary power of the engine and rotary power output from the hydrostatic transmission and outputs resultant power to a drive wheel, the planetary gear mechanism including a ring gear;
• and
• a controller that brings the hydrostatic transmission into an uncontrolled state when the hydrostatic transmission is abnormal, wherein
• the hydrostatic transmission includes:
• an HST pump that is driven by the rotary power of the engine and discharges hydraulic oil, and an HST motor that outputs rotary power by the hydraulic oil from the HST pump;
• a swash plate capable of increasing a discharge oil amount of the HST pump by increasing a tilt angle;
• and
• an electrically-controlled tilt angle adjustment mechanism capable of adjusting the tilt angle of the swash plate, wherein
• the tilt angle adjustment mechanism tilts the swash plate to a maximum tilt angle in a non-energized state, and
• the controller is configured to bring the hydrostatic transmission into an uncontrolled state, the controller brings the tilt angle adjustment mechanism into the non-energized state.

A transmission apparatus comprising:

• a hydrostatic transmission that changes rotary power of an engine steplessly and outputs the changed power;
• a planetary gear mechanism includes a sun gear, a carrier supporting a planetary gear and a ring gear, the sun gear receives rotary power output from the hydrostatic transmission;
• an input-side power transmission mechanism include a first input-side clutch mechanism and a second input-side clutch mechanism, the first input-side clutch mechanism that allows the power transmission from the rotary power of the engine to the ring gear of the planetary gear mechanism to engage and release, the second input-side clutch mechanism that allows the power transmission from the rotary power of the engine to the carrier of the planetary gear mechanism to engage and release;
• an output-side power transmission mechanism include a first output-side clutch mechanism and a second output-side clutch mechanism, the first output-side clutch mechanism that allows the power transmission from the ring gear of the planetary gear mechanism to a drive wheel to engage and release, the second output-side clutch mechanism that allows the power transmission from the carrier of the planetary gear mechanism to the drive wheel to engage and release;
• and
• a controller is configured to transmit the power from the engine to the drive wheel by engaging the second input-side clutch mechanism and the second output-side clutch mechanism and by releasing the first input-side clutch mechanism and the first output-side clutch mechanism when the hydrostatic transmission is abnormal.