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.

The invention relates to a device for supplying ports to a machine section (26) of a hydraulic machine arrangement (40), the device (10) comprising a low-pressure inlet port (12), a leakage inlet (16), a low-pressure chamber (18) having a low-pressure opening (22) for establishing fluid communication with the machine section (26), a high-pressure outlet port (14), and a high-pressure chamber (20) that is in fluid communication with the high-pressure outlet port (14), the high-pressure chamber (20) having a high-pressure opening (24) for establishing fluid communication with the machine section (26), wherein the low-pressure inlet port (12) is in fluid communication with the low-pressure chamber (18), wherein a leakage path (36) extends from the high-pressure chamber (20) through the machine section (26) to the leakage inlet (16), characterized in that the device (10) further comprises a control valve member (28) connecting the leakage inlet (16) to the low-pressure chamber (18), wherein the control valve member (28) transfers to an open state when a pressure in the leakage inlet (16) with respect to a pressure in the low-pressure chamber (18) is higher than a predefined control pressure threshold. The device (10) reduces cavitation in hydraulic machine arrangements (40).

Axial piston machine comprising a drive shaft, a drive mechanism that is connected thereto for conjoint rotation and comprises one or more drive-mechanism pistons, the piston stroke of which can be set by a swash plate, at least one return spring acting on the swash plate and a setting piston supporting on the swash plate, the axial piston machine comprising at least one control or regulating valve or at least one control or regulating unit, characterized in that a setting piston is guided in the connecting plate and a setting lever acts as a coupling member between the setting piston and the swash plate and the setting-piston axis and the setting-lever axis are positioned in a plane E1, in particular in a half plane E1* extending from the drive-shaft axis M.

A hydraulic machine includes a housing interior space and a group of hydrostatic working chambers which are mounted in said housing interior space so as to be rotatable about an axis of rotation and which, as the group rotates, are connectable alternately to a high pressure and to a low pressure of the hydraulic machine and exhibit leakage into the housing interior space. A heat exchanger device is accommodated in the housing interior space. The hydraulic machine may be associated with a hydraulic assembly and a hydraulic axle.

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.

An axial piston machine may include a rotor rotatably mounted in a housing. A plurality of cylinders may be arranged in a ring around the rotor. A plurality of pistons may each be arranged within each of the plurality of cylinders and may be constructed and arranged to selectively translate within the plurality of cylinders. A plurality of inlet openings may be defined in a cylinder head and at least one outlet opening may be defined in the housing. The plurality of cylinders may be in operative communication with the plurality of inlet openings and the at least one outlet opening. An inlet channel may be defined in the cylinder head and may extend to each of the plurality of inlet openings. An outlet channel may be defined in the housing and may be in operative communication with the at least one outlet opening. A bypass channel may be defined in the housing and may extend from the cylinder head into one of the outlet channel or a swashplate space. A bypass valve may be connected to the cylinder head or may be integrated with the cylinder head. The bypass valve may be constructed and arranged to selectively apportion a working medium to the inlet channel and the bypass channel based on a switching position of the bypass valve.

A hydrostatic axial piston machine has a drive shaft penetrating a housing on either side. In this case, the mechanically weaker of the two shaft ends is strengthened by an undercut being eliminated, said undercut defining the minimum diameter of the shaft end and thus of the entire drive shaft. Instead, the strength of the relevant shaft end is increased by a displacement of a circular bearing surface for a rolling bearing radially outwardly and away from the rolling bearing. In this case, the circular bearing surface is displaced below a compression spring which clamps the cylinder drum against a distributor plate. The resulting spacing between the circular bearing surface and the rolling bearing remaining in place is bridged by a sleeve or by a ring. A concave rounded shaft shoulder is simply formed below the sleeve and/or the ring.

An axial piston machine of oblique axis design has a pivot angle that is adjustable via a set piston and a control valve and includes a first valve slide that is linearly movable relative to a first valve axis and is connected at two opposite ends to a first or a second fluid port. The first valve slide has a central region that defines a control point at which the lower of pressures at the first and second fluid ports act. The control point is connected via a fixed first throttle and a second throttle to a housing interior. A second valve slide that is linearly movable relative to a second valve axis is configured to adjust the second throttle. The first valve axis is arranged between the set piston and the control valve or a region of the control valve and is oriented transverse to the adjusting axis.

A cylinder block includes: a plurality of cylinder bores including respective openings formed on a piston insertion end surface of the cylinder block, pistons being inserted in the respective cylinder bores and being configured to reciprocate and slide in the respective cylinder bores when the cylinder block rotates; and a cooling portion, wherein the cooling portion includes a plurality of cooling holes each formed between the adjacent cylinder bores and extending from the piston insertion end surface in an axial direction of the cylinder block.

A control mechanism for a stepless transmission is a control mechanism connected to a manipulation lever in a stepless transmission and disposed outside a housing of the transmission. The control mechanism includes: a) a piston rod connected to the manipulation lever; b) a piston provided on the piston rod coaxially with the piston rod; c) a cylinder case provided with a cylinder adapted to house the piston rod and the piston such that the piston rod and the piston are displaceable in an axial direction, the piston and the cylinder forming a first fluid chamber to be supplied with a hydraulic fluid for withdrawing the piston rod from the cylinder and a second fluid chamber to be supplied with the hydraulic fluid for introducing the piston rod into the cylinder; d) a spring adapted to bias the manipulation lever in a neutral direction coaxially with the piston rod; e) a proportional pressure control valve adapted to selectively supply the hydraulic fluid to the first fluid chamber or the second fluid chamber, the proportional pressure control valves being mounted to the cylinder case; and f) a pivot shaft adapted to support the cylinder case oscillatably with respect to the housing.