Abstract: Hydrostatic transmission apparatus for a vehicle having a front group of drive members and a rear group of drive members, a pump, a front motor and a rear motor contributing to driving respective ones of the front and rear groups of drive members; a first one of the motors and a second one of the motors connected to the first motor via a series duct also being connected to the main orifices of the pump, thereby constituting a closed transmission circuit; at least one pressure-limiting valve being interposed between the series duct and a low-pressure circuit, and being suitable for connecting the series duct to the low-pressure circuit while being controlled as a function of the high pressure of the pump. The pressure in the series duct is thus effectively limited to a pressure representative of the pressure necessary for driving the vehicle.

Abstract: A hydrostatic transmission apparatus having a main pump, two main ducts that are respectively a feed main duct and a discharge main duct for first and second hydraulic motors serving to drive two drive members of a vehicle that are situated one after the other. At least the first hydraulic motor is a dual motor made up of two elementary motors, a first one of which is connected via a series link to the second hydraulic motor. A link selector can take up a first position in which a series loop including said series link coexists with a direct loop for directly linking at least the second elementary motor to the two respective orifices of the main pump, and a second position in which at least one of said direct and series loops is bypassed by a bypass link having a constriction valve.

Abstract: Hydraulic apparatus for recovering energy, said apparatus comprising a hydraulic motor, and a high-pressure fluid source and a low-pressure fluid source. The apparatus has: an energy consumption mode, in which the fluid is transferred from the high-pressure fluid source to the low-pressure fluid source while driving the motor in rotation; and an energy accumulation mode, in which, by the action of the motor operating as a pump, the fluid is transferred from the low-pressure source to the high-pressure fluid source. The apparatus further comprises a pressure reducer disposed on a duct interconnecting the two fluid sources. In energy accumulation mode, if the level of the low-pressure source is tending to become excessively low, the reducer opens, enabling fluid to reach the low-pressure fluid source via the first duct.

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: 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 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: Hydrostatic transmission apparatus having an elementary motor with a feed enclosure and a discharge enclosure; a displacement selector suitable for taking up a bypass position, in which the feed and discharge enclosures are interconnected via a bypass link; and constriction means for constricting said bypass link.

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 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 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 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: The present invention relates to a hydrostatic transmission closed circuit comprising a fluid tank (50), a hydraulic pump (12; 212), a first engine assembly (20; 220) and a second engine assembly (30, 40; 230), said first and second engine assemblies (30, 40; 230), each comprising at least one hydraulic engine, a booster pump (14; 214), an exchange unit (60; 260), said circuit being characterised in that it also comprises a supplementary boosting line (150; 350) which removes fluid at the outlet of the exchange unit (60; 260) and boosts the hydrostatic transmission circuit at the level of the series line (104; 204).

Abstract: This invention discloses a hydraulic braking system (1) for a vehicle comprising: two pressure supply means (2, 3), two rear braking means (4, 5) and one front braking means (6), said hydraulic system (1) being characterised in that it comprises a rear inlet distributor (12), a front inlet distributor (13), a first brake distributor (10) and a second brake distributor (11), defining a standby configuration, three braking configurations pressurising: a first rear brake, a second rear brake, the two rear brakes and the front brake respectively, pressure for the front axle braking means (6) being applied through the front inlet distributor (13), the first brake distributor (10) and the second brake distributor (11).

Abstract: Hydraulic transmission apparatus including a pressurized fluid source and at least one hydraulic motor fed by said pressurized fluid source. The motor has two motor ducts for feed/discharge, and one casing duct. The motor can be operated in assisted mode, in which it generates torque or in unassisted mode in which it does not generate any torque and its pistons are maintained in the retracted position under the effect of the pressure in the casing duct. The apparatus further includes an accumulator suitable for feeding: the motor ducts during a stage of passing from the unassisted mode to the assisted mode in order to facilitate deployment of the pistons; and the casing duct during a stage of passing from the assisted mode to the unassisted mode in order to facilitate retraction of the pistons. This apparatus thus enables the motor to be positively clutched/declutched quickly.

Abstract: A hydraulic transmission system for a vehicle, the system including: a main pump serving to feed with fluid at least one hydraulic motor for driving a vehicle mover member; an auxiliary pump, the main pump and the auxiliary pump being suitable for being actuated jointly by drive means; and a “bypass” connection between a delivery orifice of the auxiliary pump and an unpressurized reservoir. First constriction means, arranged on the bypass connection, maintain a pump protection pressure in a pump protection portion of the bypass connection; this pressure is applied to the main orifices of the main pump when said pump is actuated but is not delivering, thereby ensuring that the pump is protected.

Abstract: A hydraulic motor device including a hydraulic motor having a cylinder block and a cam that are mounted to move in rotation relative to each other. The motor has a fluid distributor for the cylinders, a portion of which distributor is constrained in rotation with the cam, and a stationary distribution coupling connecting the distributor to a fluid feed and to a fluid discharge. The motor has a through passage disposed along the axis of rotation for the purpose of receiving a transmission shaft segment. The motor can be declutched by radially uncoupling the pistons from the cam, the cylinder block remaining stationary relative to the reference frame of the vehicle, and the cam being constrained in rotation with a transmission shaft segment that is disposed in the through passage. The device may be used in addition to or as a replacement for a mechanical transmission.

Abstract: A hydraulic circuit including a first motor set, and a second motor set for driving vehicle-moving means situated one behind the other. The circuit has first, second, third, and fourth main ducts for feeding the motor sets in parallel. The device includes a selector suitable for taking up a first stable position making the feeding in parallel possible by interconnecting in pairs the feed and discharge main ducts, and for taking up a second stable position in which one of the motor sets is inactive because one of the main ducts is connected to one of main ducts of the other set. Between the stable positions, the selector can take up a temporary position, in which all four main ducts are interconnected. At least while the selector is moving in one direction between its two stable positions, the temporary position is sustained in an intermediate stage during which at least one of the interconnections between the main ducts of the first and second motor sets is constricted.

Abstract: A hydrostatic transmission apparatus having a main pump, two main ducts that are respectively a feed main duct and a discharge main duct for first and second hydraulic motors serving to drive two drive members of a vehicle that are situated one after the other. At least the first hydraulic motor is a dual motor made up of two elementary motors, a first one of which is connected via a series link to the second hydraulic motor. A link selector can take up a first position in which a series loop including said series link coexists with a direct loop for directly linking at least the second elementary motor to the two respective orifices of the main pump, and a second position in which at least one of said direct and series loops is bypassed by a bypass link having a constriction valve.