The invention relates to a hydraulic pump wherein a barrel is in sliding connection with a shaft and is driven in rotation by the shaft. A housing is formed in the barrel, the shaft sliding in the housing while projecting from the front face of the barrel. The housing and the shaft defining between them a balancing chamber, the balancing chamber being connected to a delivery aperture in such a way that fluid in the balancing chamber exerts a compressive force on the barrel which tends to press the barrel against a port plate.

A pump device (1) is provided comprising: a shaft (2), rotor means (3a, 3b) fixed to said shaft (2) in rotational direction, said rotor means (3a, 3b) having pressure chambers (5a, 5b) the volume of which varying during a rotation of said rotor means (3a, 3b), port plate means (15a, 15b) having a through going opening (16a, 16b) for each of said pressure chambers (5a, 5b) and being connected to said rotor means (3a, 3b) in rotational direction, and valve plate means (17a, 17b) cooperating with said port plate means (15a, 15b). It is intended to pressurize a high volume of fluid, in particular water, within a limited space. To this end said rotor means (3a, 3b) comprise a first rotor (3a) and at least a second rotor (3b), both rotors being fixed to said shaft (2) in rotational direction, said first rotor (3a) having at least a first pressure chamber (5a) and said second rotor (3b) having at least a second pressure chamber (5b), said port plate means (15a, 15b) having a first port plate (15a) and at least a second port plate (15b), said first port plate (15a) having a through going opening (16a) for said first pressure chamber (5a) and being connected to said first rotor (3a) in rotational direction, said second port plate (15b) having a through going opening (16b) for said second pressure chamber (5b) and being connected to said second rotor (3b) in rotational direction, said valve plate means (17a, 17b) having a first valve plate (17a) and at least a second valve plate (17b), said first valve plate (17a) cooperating with said first port plate (15a), and said second valve plate (17b) cooperating with said second port plate (15b), wherein at least one of said first rotor (3a) and said second rotor (3b) comprises force generating means (19) pressing said second port plate (15b) against said second valve plate (17b) even in absence of hydraulic pressure in said second pressure chamber (5b).

A pump device (1) is provided comprising: a shaft (2), rotor means (3a, 3b) fixed to said shaft (2) in rotational direction, said rotor means (3a, 3b) having pressure chambers (5a, 5b) the volume of which varying during a rotation of said rotor means (3a, 3b), port plate means (15a, 15b) having a through going opening (16a, 16b) for each of said pressure chambers (5a, 5b) and being connected to said rotor means (3a, 3b) in rotational direction, and valve plate means (17a, 17b) cooperating with said port plate means (15a, 15b). It is intended to pressurize a high volume of fluid, in particular water, within a limited space. To this end said rotor means (3a, 3b) comprise a first rotor (3a) and at least a second rotor (3b), both rotors being fixed to said shaft (2) in rotational direction, said first rotor (3a) having at least a first pressure chamber (5a) and said second rotor (3b) having at least a second pressure chamber (5b), said port plate means (15a, 15b) having a first port plate (15a) and at least a second port plate (15b), said first port plate (15a) having a through going opening (16a) for said first pressure chamber (5a) and being connected to said first rotor (3a) in rotational direction, said second port plate (15b) having a through going opening (16b) for said second pressure chamber (5b) and being connected to said second rotor (3b) in rotational direction, said valve plate means (17a, 17b) having a first valve plate (17a) and at least a second valve plate (17b), said first valve plate (17a) cooperating with said first port plate (15a), and said second valve plate (17b) cooperating with said second port plate (15b), wherein at least one of said first rotor (3a) and said second rotor (3b) comprises force generating means (19) pressing said second port plate (15b) against said second valve plate (17b) even in absence of hydraulic pressure in said second pressure chamber (5b).

A control plate, for alternatingly fluidically connecting hydrostatic operating chambers, in particular of an oblique axis type axial piston machine, with pressure medium connections, includes a first end face, a second end face, at least a first recess, a first kidney-like control opening, and at least one through-recess. The first face extends transversely to a rotation axis. The second face faces away from the first face. The first recess is bounded in the first end face by the first control opening, and at least partially forms the at least one through recess, which extends toward the second end face from the first end face at an end portion of the first control opening, and which is arranged in or counter to a rotation direction of the rotation axis. An oblique axis construction type axial piston machine includes such a control plate.

A cylinder block for use in an integrated drive generator has a shaft portion with a relatively small outer diameter and a cylindrical body portion having a larger outer diameter than the shaft portion, and said cylindrical body portion formed with a plurality of piston chambers, said cylindrical body portion extending from a first end to a second end, said second end being provided with cylindrical ports leading into said piston chambers and said cylindrical ports having a third end and a fourth end wherein a ratio of a first distance from said first end to said fourth end to a second distance from said first end to said second end being between 0.91 and 0.93. A generator and a method are also described.

A hydraulic drive device includes a running surface having a pair of arcuate kidney ports formed thereon. The running surface also includes a plurality of pressure gradient grooves formed on the running surface, each pressure gradient groove having a proximal end adjacent to a respective one of the ends of one of the kidney ports and a distal end. The distal end of one of the pressure gradient grooves associated with one kidney port may overlap the distal end of a pressure gradient groove associated with the other kidney port. The distal end of at least one of the pressure gradient grooves is located outside the circumference of a pitch circle that passes through the center of each kidney port. The distal end of at least one of the other pressure gradient grooves is located inside the pitch circle circumference.

A rotary type valve plate compressor may include a shaft, a housing through which the shaft passes, a plurality of cylinders mounted in the housing, a piston received in the cylinder and to be moved forward and rearward in response to rotational operation of a swash plate, and a rotary type valve plate to receive a rotational force of the shaft and to open and close a refrigerant passage hole through which refrigerant passes, based on a phase of the piston.

An inlet baffle chamber (40) is provided in the port cover (26) of a piston pump. The inlet baffle chamber (26) fluidly connects a compressed piston chamber to an adjacent lower pressure piston chamber while the lower pressure piston chamber is in the suction cycle and separately receiving fluid from an inlet manifold (38) of the port cover (26). Instead of de-compressing high pressure fluid directly to pump's inlet (36) as in prior art pumps, the inlet baffle chamber (40) directs fluid to the next piston that is already in the suction cycle.

A hydraulic machine includes a first member (1) having a first structure (2) for a hydraulic medium opening in a first interface surface (3) and a second member having a second structure for the hydraulic medium opening in a second interface surface is described, the first interface surface (3) being in contact with the second interface surface, wherein at least one of the members (1) is provided with a support element (6) surrounding the member (1). Such a machine should have a good efficiency. To this end the support element (6) has a strength varying in circumferential direction around the member (1) and/or in thickness direction in a middle region of the member (1).

The present disclosure relates to a sealing assembly for a hydraulic piston pump/motor. The sealing assembly comprises a cylinder block, a fluid distribution member, and a sealing member disposed between the cylinder block and the fluid distribution member. The sealing member encloses and seals a fluidic connection between the cylinder block and the fluid distribution member. The present disclosure further relates to a hydraulic piston pump/motor comprising said sealing assembly.