A hydraulic drive unit includes: a pump; a pair of supply-discharge lines; a valve block; a sealed tank; a suction line that leads hydraulic oil in the sealed tank to the pump; a connecting line that connects an air vent port of the pump to the suction line; and a gas-liquid separator that separates air and the hydraulic oil flowing through the connecting line from each other. The pump is disposed upward of the valve block and the sealed tank in a vertical direction.

A hydraulic transaxle comprises an axial piston hydraulic pump having a variable displacement, and a transaxle casing incorporating the hydraulic pump. The hydraulic pump includes a movable swash plate and a pair of trunnion shafts. The transaxle casing includes a pair of side walls, and includes a pair of casing holes each of which penetrates each of the side walls between an inside and an outside of the transaxle casing. The pair of trunnion shafts are passed through the respective casing holes. The swash plate is formed with a pair of swash plate holes in the respective side portions facing the respective side walls in the inside of the transaxle casing. Proximal end portions of the respective trunnion shafts are inserted into the respective swash plate holes. A distal end portion of one of the trunnion shafts projects from the corresponding casing hole to the outside of the transaxle casing.

A hydraulic transaxle comprises an axial piston hydraulic pump having a variable displacement, and a transaxle casing incorporating the hydraulic pump. The hydraulic pump includes a movable swash plate and a pair of trunnion shafts. The transaxle casing includes a pair of side walls, and includes a pair of casing holes each of which penetrates each of the side walls between an inside and an outside of the transaxle casing. The pair of trunnion shafts are passed through the respective casing holes. The swash plate is formed with a pair of swash plate holes in the respective side portions facing the respective side walls in the inside of the transaxle casing. Proximal end portions of the respective trunnion shafts are inserted into the respective swash plate holes. A distal end portion of one of the trunnion shafts projects from the corresponding casing hole to the outside of the transaxle casing.

A hydraulic transaxle includes a transaxle casing including an upper transaxle housing and a lower casing, hydrostatic transmission (HST), and an axle. The HST has a hydraulic pump and a hydraulic motor that are fluidly connected to each other. The hydraulic motor has a motor shaft that is drivingly connected to the axle through a reduction gear train that is disposed between the hydraulic pump and the axle. Reduction gear train has a gear shaft supported by the upper transaxle housing via a ball bearing. At least a part of the upper transaxle housing is formed by a gear top cover made of metal and covering the reduction gear train. Ball bearing is supported by the upper transaxle housing and the gear top cover.

A hydraulic transaxle includes a transaxle casing including an upper transaxle housing and a lower casing, hydrostatic transmission (HST), and an axle. The HST has a hydraulic pump and a hydraulic motor that are fluidly connected to each other. The hydraulic motor has a motor shaft that is drivingly connected to the axle through a reduction gear train that is disposed between the hydraulic pump and the axle. Reduction gear train has a gear shaft supported by the upper transaxle housing via a ball bearing. At least a part of the upper transaxle housing is formed by a gear top cover made of metal and covering the reduction gear train. Ball bearing is supported by the upper transaxle housing and the gear top cover.

An automatic transmission assembly for mounting to a power-source includes a torque converter operatively connected to the power-source. The transmission assembly also includes a turbine shaft for receiving power-source torque from the torque converter. The transmission assembly additionally includes a torque transfer system, having a gear-train and a hydraulic pressure operated torque-transmitting device, for receiving the torque from the turbine shaft and selecting an input-to-output speed-ratio of the transmission. The transmission assembly also includes an output member for receiving torque from torque transfer system and outputting the torque to drive a load. The turbine shaft defines a first passage configured to supply hydraulic pressure to the torque-transmitting device and a second passage configured to vent to atmosphere. The turbine shaft additionally defines a third passage fluidly connecting the first passage to the second passage and thereby configured to bleed air from the torque-transmitting device.

An automatic transmission assembly for mounting to a power-source includes a torque converter operatively connected to the power-source. The transmission assembly also includes a turbine shaft for receiving power-source torque from the torque converter. The transmission assembly additionally includes a torque transfer system, having a gear-train and a hydraulic pressure operated torque-transmitting device, for receiving the torque from the turbine shaft and selecting an input-to-output speed-ratio of the transmission. The transmission assembly also includes an output member for receiving torque from torque transfer system and outputting the torque to drive a load. The turbine shaft defines a first passage configured to supply hydraulic pressure to the torque-transmitting device and a second passage configured to vent to atmosphere. The turbine shaft additionally defines a third passage fluidly connecting the first passage to the second passage and thereby configured to bleed air from the torque-transmitting device.

Degasifying apparatus is for eliminating gases, such as ambient air, from fluids, such as oil. The apparatus has at least one permeable membrane (26) that lets the gas to be eliminated from the fluid (22) penetrate through the permeable membrane and retains the liquid moiety of the fluid within the permeable membrane.

Degasifying apparatus is for eliminating gases, such as ambient air, from fluids, such as oil. The apparatus has at least one permeable membrane (26) that lets the gas to be eliminated from the fluid (22) penetrate through the permeable membrane and retains the liquid moiety of the fluid within the permeable membrane.

A hydraulic drive unit includes: a pump; a pair of supply-discharge lines; a valve block; a sealed tank; a suction line that leads hydraulic oil in the sealed tank to the pump; a connecting line that connects an air vent port of the pump to the suction line; and a gas-liquid separator that separates air and the hydraulic oil flowing through the connecting line from each other. The pump is disposed upward of the valve block and the sealed tank in a vertical direction.