Abstract: Hydraulic device such as a motor or a pump comprising a first assembly of parts (1C) including a housing part, and a second assembly of parts (1D) fixed to said first assembly. Said assemblies present respectively a first and a second contact face (1C?,1D?), which are stressed towards each other and placed in mutual contact by means (15) exerting axial stress. One at least of the first and second contact faces has a rough friction surface. Because of the latter, high torque can be transmitted between the two assemblies. Production process for such a hydraulic device.

Abstract: The present invention relates to a hydraulic apparatus comprising a hydraulic machine comprising a machine shaft having a proximal end and a distal end, adapted to drive a cylinder block, a clutch comprising a clutch shaft having a proximal end and a distal end, and engaging means for selectively engaging said clutch shaft with said machine shaft, said engaging means comprising a plurality of friction discs linked to the distal end of the clutch shaft and a plurality of friction discs linked to the proximal end of the machine shaft, said discs being disposed radially around said machine shaft, characterized in that the distal end of said clutch shaft is bell-shaped so as to surround the proximal end of said machine shaft, said bell shape defining an inner space where the proximal end of the machine shaft and the friction discs linked to the clutch shaft are located.

Abstract: Hydraulic transmission circuit with N hydraulic motors, wherein each motor comprises N sub-motors, all N2 sub-motors having the same cylinder displacement. The circuit comprises one common feed duct, adapted for receiving fluid under pressure, and to which one feed sub-motor of each motor is connected; one common exhaust duct, adapted for ejecting exhaust fluid, and to which one exhaust sub-motor of each motor is connected; N serial ducts, each serial duct connecting a feed, first sub-motor to an exhaust, N-th sub-motor via N?2 interposed sub-motors, these N connected sub-motors respectively belonging to the N motors. This circuit allows tight synchronization of the N hydraulic motors.

Abstract: A method for manufacturing radial pistons for a hydraulic motor by machining cylindrical transverse holes at regular intervals in a bar, and, in order to form two adjacent pistons, cutting up the bar on a transverse cutting-up plane passing through one of said holes so that a first portion of said hole forms a cradle-shaped recess in the base of the first one of the two adjacent pistons and so that another portion of said hole forms a cradle-shaped recess in the top of the second one of the two adjacent pistons.

Abstract: The present invention relates to a hydraulic circuit including: a high pressure line (HP) and a low pressure line (BP), the pressure in said high pressure line (HP) being greater than the pressure in said low pressure line (BP), a hydraulic machine (2) having two ports (21, 22) designed to be connected to said high pressure (HP) and low pressure (BP) lines, a first of said ports (21) being a hydraulic fluid intake port and the second (22) of said ports being a hydraulic fluid discharge port, said circuit being characterized in that it includes sequential connection means (4, 5, 8, 9), designed to connect said ports (21, 22) of said hydraulic machine (2) to said high (HP) and low (BP) pressure lines.

Abstract: The present invention relates to a hydraulic circuit including: a variable displacement pump, a booster pump, a pump control controlling the displacement of the variable displacement pump, supplied by the booster pump via pressure control means, the pump control including a double-acting cylinder including a first chamber and a second chamber, wherein the first chamber is connected to said booster pump via a first setting line including pressure reducing means, the second chamber is connected to said booster pump via a second setting line including a proportional pressure reducer, such that control of the proportional pressure reducer controls the displacement of the variable displacement pump.

Abstract: A hydraulic transmission circuit comprising three or four coupled hydraulic elementary motors, each elementary motor having a first and a second secondary enclosure. The circuit includes four distribution valves for which the respective outlet channels may be selectively connected to two main conduits for supplying fluid to and discharging fluid from the circuit. The outlet channels of the first and second valves are connected to at least one of the first secondary enclosures; those of the third and fourth valves are connected to at least one of the second secondary enclosures. Each of the elementary motors has a first secondary enclosure connected to a single valve from among the first or second valve and a second secondary enclosure connected to a single valve from among the third or fourth valve. The valve pairs thereby connected to said elementary motors respectively, are all distinct, two by two.

Abstract: A hydraulic circuit including: at least one primary motor comprising at least first and second distinct sub-motors, the first sub-motor having a first main orifice, and the second sub-motor having a second main orifice; and at least one secondary motor; in which circuit said first main orifice of the primary motor(s) is connected to a first main orifice of the secondary motor(s) via a first series duct, and the second main orifice of the primary motor(s) is connected to a second main orifice of the secondary motor(s) via a second series duct. This configuration of circuit makes coupling possible between the primary motor(s) and the secondary motor(s).

Abstract: A hydrostatic transmission including a main pump, two main ducts serving respectfully as feed and as discharge for first and second hydraulic motors that serve to drive disposed one after the other. A bypass valve can take up a reduced-speed position in which the feed main orifices are connected to the discharge main duct, and an increased-speed position in which one of the motors is bypassed, the feed main orifice of the motor being connected to the discharge main duct via a bypass link, while the other main orifices continue to have their respective links. The apparatus further includes a constriction suitable for being activated to restrict the flow of fluid through the bypass link.

Abstract: The present invention relates to a subassembly for forming a hydraulic motor after assembly onto an assembly including a shaft, said subassembly including a cover forming a housing element, a multilobe cam, a cylinder block opposite the cam, pistons guided so as to slide radially within the respective cylinders of the cylinder block and bearing on the lobes of the cam, and a valve intended to apply pressurized fluid to said pistons in series, wherein said subassembly includes means for temporarily attaching the cylinder block to the cover and means for accessing an element of the valve through the cover in order to enable, during installation, the angular positioning of said element with respect to the shaft, followed by the attachment thereof to the shaft. The present invention also relates to a method for assembling such a hydrobase.

Abstract: A piston for a hydraulic motor including a body having a guiding and sealing surface, a base, and a top, which top is providing with a cradle-shaped recess. The base is provided with an additional cradle-shaped recess whose concave surface faces in the direction in which the concave surface of the recess in the top faces.

Abstract: An hydraulic transmission device (10,110) comprising an hydraulic motor (16, 18), an hydraulic pump (20), a fluid accumulator (22). The device has an accumulator-driven mode, an energy-recovery mode, a pump-driven mode. In the pump-driven mode, the pump supplies the motor with fluid drawn from an unpressurized reservoir; and in the energy-recovery mode, the motor is supplied by the pump drawing fluid from said reservoir. An assembly (1) comprising a device (10,110) as defined above, a shaft (11, 13), and a mass (12, 14) mounted eccentrically on the shaft.

Abstract: A circuit having at least one hydraulic motor, two main ducts for feeding or discharging the at least one motor, a low-pressure fluid source, and a high-pressure accumulator forming a high-pressure fluid source. The circuit is suitable for operating in an energy recovery mode in which the feed main duct is connected to the low-pressure fluid source and the discharge main duct is connected to the high-pressure accumulator, and in an energy delivery mode in which the connections are inverted. The low-pressure fluid source has a high-flow-rate booster pump suitable for delivering a flow-rate of fluid that is sufficient to feed fluid to the at least one hydraulic motor while the motor is at maximum speed in energy recovery mode, and an adjustable pressure limiter suitable for being controlled so as to cause the pressure of the fluid at the outlet of the low-pressure fluid source to vary.

Abstract: A hydraulic circuit having a brake pipe suitable for being connected to a pressurized fluid source or to a pressure-free reservoir, i.e. to a reservoir without excess pressure, via a proportional pressure reducer controlled by an electronic control unit (ECU). The circuit includes link solenoid-valve means suitable for connecting the proportional pressure reducer to the reservoir or, via a calibrated pressure reducer, to the pressurized fluid source.

Abstract: A hydraulic valve having firstly a feed port, a low-pressure link port, and a high-pressure link port, which ports are respectively connected to the feed and discharge ducts of a hydraulic motor, to a low-pressure fluid source, and to a high-pressure accumulator, and secondly an auxiliary port. The valve has a slide that can take up a neutral position for connecting together the feed, discharge, and auxiliary ports, an energy recovery position for connecting together respectively the feed and low-pressure ports, and the discharge and high pressure ports, and an energy delivery position for connecting together respectively the feed and high-pressure ports, and the discharge and low-pressure ports. The slide is caused to move from its neutral position to its other positions by control signals and the auxiliary port can be connected to a reservoir or to a clutch fluid source for clutching or declutching the motor.

Abstract: A piston including a body having a guiding and sealing surface, a base, and a top, which top is provided with a cradle-shaped recess in which a journal-bearing lining is retained by stop surfaces formed on the edges of the recess. The stop surfaces are formed by deforming the edges of the recess towards the inside thereof.

Abstract: A piston for a hydraulic motor including a body having a guiding and sealing surface, a base, and a top, which top is providing with a cradle-shaped recess. The base is provided with an additional cradle-shaped recess whose concave surface faces in the direction in which the concave surface of the recess in the top faces.

Abstract: A valve including a valve body having an inlet port and an outlet port, a valve stem, a valve seat, an opening control chamber for the valve stem, which chamber, by being fed with fluid, urges the valve stem to move towards the open position of the valve, a return spring of opposing effect, and a piston suitable for sliding in the body so as to urge contact to be established between the valve stem and the seat. The valve seat is formed on the piston, which piston is provided with a bore in which the valve stem is in its closure movement, the fluid flows out via a constriction from a damping chamber.

Abstract: A hydraulic mechanism including a cylinder block having radial pistons and mounted to rotate in a stationary casing, and a distribution cover that forms a portion of the casing that has feed and discharge ducts that extend between an outside face and inside of face of the cover. The internal distributor has distribution ducts that are selectively connected to the feed and discharge ducts that open out into a distribution face that is perpendicular to the axis of rotation and that is disposed against the communication face of the cylinder block so as to cause the distribution ducts to communicate with the cylinder ducts. In a zone defined radially outwards by end-wall portions of the cylinders, a transverse face of the cylinder block is provided with an axial setback in which at least a portion of the distributor is disposed.

Abstract: A motor having two series of distribution ducts each having two groups of ducts. The displacement selector is able to occupy a large displacement position in which the first groups of distribution ducts of the first series are connected to a main duct while the second groups are connected to the other main duct, and a small displacement configuration in which the first group of distribution ducts of the first series is connected to a main duct, the second group of distribution ducts of the first series is connected to the other main duct and a bypass connection exists between the first and the second group of distribution ducts of the second series. The device has a restriction in order, in the small displacement configuration, to restrict this bypass connection.