A swash-plate type piston pump includes a cylinder block configured to be rotated with rotation of a driving shaft, a plurality of pistons accommodated in a plurality of cylinders provided in the cylinder block, a swash plate configured to reciprocate the piston so that a volume chamber of the cylinder is expanded/contracted with the rotation of the cylinder block, an biasing mechanism configured to bias the swash plate in a direction where a tilting angle is made larger, a control pin configured to drive the swash plate in a direction where the tilting angle is made smaller in accordance with a rise in a load pressure of a pressure chamber, and a discharge channel configured to discharge the load pressure of the pressure chamber.

The present invention relates to a rotary barrel pump (6) comprising two plates: a mobile plate (2) also driven by drive shaft (5) and a variable-inclination plate (7), the two plates (2, 7) being linked to one another by a pivot connection.

A hydraulic transaxle of the present invention includes an axle, a hydraulic static transmission (HST), a center case that has pair of oil passages for circulating the hydraulic oil between the hydraulic pump and the hydraulic motor, and a gear mechanism that transmits an output of the HST to the axle. A case supports the axle and accommodates the HST while also forming an oil reservoir. A hydraulic motor of the HST includes a motor shaft, a cylinder block with a plurality of cylinders fixed to the motor shaft, a plurality of pistons inserted into the cylinders, a fixed swash plate abutted by the plurality of pistons, and a fixed swash plate holder that supports the fixed swash plate with respect to the case. The motor shaft of the hydraulic motor is supported by the center case and the fixed swash plate holder.

A piston pump includes a first biasing mechanism configured to bias a swash plate in accordance with supplied control pressure, a second biasing mechanism configured to bias the swash plate against the first biasing mechanism, and a regulator configured to control the control pressure led to the first biasing mechanism in accordance with discharge pressure of the piston pump, wherein the second biasing mechanism has a pressure chamber to which the discharge pressure is led, and a control piston configured to be biased toward the swash plate by the discharge pressure led to the pressure chamber, and the regulator has a biasing member configured to bias the control piston toward the swash plate, and a control spool configured to be moved in accordance with biasing force of the biasing member, the control spool being configured to adjust fluid pressure.

A piston pump includes a first biasing mechanism configured to bias a swash plate in accordance with supplied control pressure, a second biasing mechanism configured to bias the swash plate against the first biasing mechanism, and a regulator configured to control the control pressure led to the first biasing mechanism in accordance with discharge pressure of the piston pump, wherein the second biasing mechanism has a pressure chamber to which the discharge pressure is led, and a control piston configured to be biased toward the swash plate by the discharge pressure led to the pressure chamber, and the regulator has a biasing member configured to bias the control piston toward the swash plate, and a control spool configured to be moved in accordance with biasing force of the biasing member, the control spool being configured to adjust fluid pressure.

The present invention relates to an electronically controlled valve for a variable displacement pump, a hydraulic pump and a hydraulic pump system with switchable control functions. Multiple control functions of different types of hydraulic pumps can be implemented via one single electronically controlled valve combined with control elements and sensors. The hydraulic pump systems can be easily integrated into the overall application systems for intelligent control.

The present invention relates to an electronically controlled valve for a variable displacement pump, a hydraulic pump and a hydraulic pump system with switchable control functions. Multiple control functions of different types of hydraulic pumps can be implemented via one single electronically controlled valve combined with control elements and sensors. The hydraulic pump systems can be easily integrated into the overall application systems for intelligent control.

A joint for the angularly adjustable drive-connection of a cylinder block and a driveshaft of a hydrostatic bent axis piston unit. The joint has a shank which is rotatable about its longitudinal axis defining a joint axis, on both ends of the shank roller carriers project radially and basically perpendicular to the joint axis. On each roller carrier a roller is provided rotatable around a roller axis. The rollers are secured in axial direction against slipping-off of the roller carriers by means of an embossed area located axially outside of the roller on the respective distal end portion of the roller carrier.

A hydrostatic positive displacement machine has an adjustable swept volume, and has a lifting element, a rotor with positive displacement elements supported on the lifting element, and a hydraulic adjusting device that adjusts the swept volume and includes an adjusting piston that is mounted in or on a cylinder, is movable axially rectilinearly in relation to the cylinder, and is adjacent to a pressurizable adjusting chamber. A bearing gap is formed between a circular-cylindrical bearing surface of the adjusting piston and a circular-cylindrical bearing surface of the cylinder. The adjusting piston is mounted hydrostatically, wherein at least three pressure pockets are distributed uniformly in a row over the circumference of a bearing surface. Pressure fluid flows into each pressure pocket via a fixed throttle, which is assigned only to the respective pressure pocket, and flows out of each pressure pocket via the bearing gap.

A hydraulic rotary machine configured to reduce sliding resistance of a reciprocating piston and to suppress a reduction in volumetric efficiency corresponding to an amount of leakage of hydraulic oil. A piston pump includes a rotor shaft, a cylinder block, a piston head, a piston rod, a retainer, a swash plate, and a tilt regulation mechanism. When the tilt regulation mechanism rocks the swash plate, the amount of discharge from the piston pump is variably changed. The retainer which rotates with both the piston head and the piston rod is supported by a retainer bush provided to the rotor shaft. The retainer sphere section of the retainer and the retainer bush sphere section of the retainer bush have spherical shapes having the same curvature. During the regulation of tilt, the retainer rocks while the retainer bush sphere section is in sliding contact with the retainer bush.