A travel control device is provided with hydraulic pumps of a variable capacity type that are driven by an engine; hydraulic motors that are driven by discharged oil from the hydraulic pumps; traveling devices that are rotation-driven by the hydraulic motors; a travel operation lever that is operated so as to instruct a traveling operation; a first control valve for generating a charged hydraulic pressure by adjusting the discharged oil from a charge pump and a second control valve for generating a capacity control hydraulic pressure in accordance with the operation of the travel operation lever. The first control valve is designed to pressure-adjust and generate a charged hydraulic pressure in accordance with the rotation speed of the engine, and the hydraulic pump is subjected to a variable capacity control process by a capacity control hydraulic pressure that is pressure-adjusted and generated by the second control valve.

A transmission system includes a power take-off for driving an implement and a hydrostatic unit for transmitting power from the engine to the power take-off. The hydrostatic unit includes a first hydraulic power unit having a first connection line and a second connection line, and a second hydraulic power unit having a first connection line and a second connection line. The hydrostatic unit also includes a valve for connecting the first hydraulic power unit and the second hydraulic power unit, the valve being positionable at least in a first position, in a second position and in a neutral position.

A transmission system includes a power take-off for driving an implement and a hydrostatic unit for transmitting power from the engine to the power take-off. The hydrostatic unit includes a first hydraulic power unit having a first connection line and a second connection line, and a second hydraulic power unit having a first connection line and a second connection line. The hydrostatic unit also includes a valve for connecting the first hydraulic power unit and the second hydraulic power unit, the valve being positionable at least in a first position, in a second position and in a neutral position.

A hydrostatic transmission for a working machine having a frame, an engine on the frame, and at least one wheel driven by the hydrostatic transmission is disclosed. The hydrostatic transmission includes a housing, a hydraulic pump, the hydraulic pump driven by an output shaft from the engine, a hydraulic motor for driving an output shaft connected to the at least one wheel, a first fluid line fillable with hydraulic fluid to be maintained under a first pressure, a second fluid line fillable with hydraulic fluid to be maintained under a second pressure, a first check valve for allowing hydraulic fluid to enter the first fluid line, a second check valve for allowing hydraulic fluid to enter the second fluid line, and an entrained air deflector for preventing hydraulic fluid entrained with air from entering the first check valve and the second check valve.

A rotary actuator includes a central housing; an output shaft that extends through the central housing; a vane that is mechanically coupled to the output shaft and divides the central housing into a first chamber and a second chamber; and a flow control mechanism that is moveable within the central housing and including a high pressure port and a low pressure port for communicating hydraulic fluid into and from the first and second chambers. The flow control mechanism is moveable to position the high pressure port and low pressure port relative to the first chamber and the second chamber for communication of the hydraulic fluid, thereby generating a pressure differential across the chambers. The vane rotates within the central housing in response to the pressure differential, and rotation of the vane drives the output shaft. A motor is configured to receive control signals to drive the movement of the flow control mechanism.

A rotary actuator includes a central housing; an output shaft that extends through the central housing; a vane that is mechanically coupled to the output shaft and divides the central housing into a first chamber and a second chamber; and a flow control mechanism that is moveable within the central housing and including a high pressure port and a low pressure port for communicating hydraulic fluid into and from the first and second chambers. The flow control mechanism is moveable to position the high pressure port and low pressure port relative to the first chamber and the second chamber for communication of the hydraulic fluid, thereby generating a pressure differential across the chambers. The vane rotates within the central housing in response to the pressure differential, and rotation of the vane drives the output shaft. A motor is configured to receive control signals to drive the movement of the flow control mechanism.

An example pump includes: (i) a swash block having (a) a first trunnion arm, (b) a second trunnion arm, and (c) a first curved support surface and a second curved support surface disposed on an exterior surface of the swash block; and (ii) a housing comprising (a) a first bore, (b) a second bore, and (c) an internal chamber having a first curved bushing and a second curved bushing, where the swash block is supported within the internal chamber of the housing by the first trunnion arm being positioned in the first bore of the housing, the second trunnion arm being positioned in the second bore of the housing, the first curved support surface being positioned against the first curved bushing of the housing, and the second curved support surface being positioned against the second curved bushing of the housing.

An example pump includes: (i) a swash block having (a) a first trunnion arm, (b) a second trunnion arm, and (c) a first curved support surface and a second curved support surface disposed on an exterior surface of the swash block; and (ii) a housing comprising (a) a first bore, (b) a second bore, and (c) an internal chamber having a first curved bushing and a second curved bushing, where the swash block is supported within the internal chamber of the housing by the first trunnion arm being positioned in the first bore of the housing, the second trunnion arm being positioned in the second bore of the housing, the first curved support surface being positioned against the first curved bushing of the housing, and the second curved support surface being positioned against the second curved bushing of the housing.

A vehicle drive-train with a drive engine, a drive output and a transmission device connected in the power flow between the drive engine and the drive output. The transmission device has at least two transmission units whose transmission ratios can be varied continuously, at least in some ranges, and which are arranged in power-trains running parallel with one another between the drive engine and the drive output. The power-trains can each be functionally connected with a respective axle of the drive output. At least one shifting element is provided by which the power-trains can be functionally connected in the area between the transmission units and the drivable axles. In addition, a method for operating the vehicle drive-train is described, in which the shifting element is actuated as a function of torque to be transmitted via the transmission device between the drive engine and the drive output.

A vehicle drive-train with a drive engine, a drive output and a transmission device connected in the power flow between the drive engine and the drive output. The transmission device has at least two transmission units whose transmission ratios can be varied continuously, at least in some ranges, and which are arranged in power-trains running parallel with one another between the drive engine and the drive output. The power-trains can each be functionally connected with a respective axle of the drive output. At least one shifting element is provided by which the power-trains can be functionally connected in the area between the transmission units and the drivable axles. In addition, a method for operating the vehicle drive-train is described, in which the shifting element is actuated as a function of torque to be transmitted via the transmission device between the drive engine and the drive output.