Abstract: The present invention concerns a hydraulic pressure amplifier device comprising a casing (10) having two chambers (12, 14) of different cross-sections which house a staged piston (20) comprising two piston sections (22, 24) with cross-sections respectively el matching the chambers (12, 14), and means (30) for controlling the movement of the piston (20), characterised by the fact that the control means (30) are formed of an electronic control driven by means for estimating the ends-of-stroke of the piston (20) without an end-of-stroke sensor or mechanical stop.

Abstract: The present invention concerns a hydraulic pressure amplifier device comprising a casing (10) having two chambers (12, 14) of different cross-sections which house a staged piston (20) comprising two piston sections (22, 24) with cross-sections respectively el matching the chambers (12, 14), and means (30) for controlling the movement of the piston (20), characterised by the fact that the control means (30) are formed of an electronic control driven by means for estimating the ends-of-stroke of the piston (20) without an end-of-stroke sensor or mechanical stop.

Abstract: An emergency braking device including an actuator (2), a pressurizing circuit (3) supplying the actuator (2) via a control pressure and a discharge circuit (4). The discharge circuit (4) includes restrictors (13, 14) for controlling the pressure and/or flow rate of the supply fluid of the actuator (2) during a discharge of the actuator. The restrictors (13, 14) are configured to define an intermediate pressure between a low pressure level and the control pressure of the actuator (2).

Abstract: The present invention relates to a hydraulic-assistance system for motor vehicles, comprising a primary motor (M) and two hydraulic machines (140; 240, 250) connected by a hydraulic circuit such that when a first hydraulic machine (140) operates as a pump, the second hydraulic machine (240, 250) operates as a motor.

Abstract: The invention relates to an emergency braking device comprising an actuator (2), a pressurizing circuit (3) supplying the actuator (2) via a control pressure and a discharge circuit (4), characterized in that the discharge circuit (4) comprises means (13, 14) for controlling the pressure and/or flow rate of the supply fluid of the actuator (2) during a discharge of the actuator, these control means (13, 14) being configured to define an intermediate pressure between a low pressure level and the control pressure of the actuator (2).

Abstract: The present invention relates to a hydraulic-assistance system for motor vehicles, comprising a primary motor (M) and two hydraulic machines (140; 240, 250) connected by a hydraulic circuit such that when a first hydraulic machine (140) operates as a pump, the second hydraulic machine (240, 250) operates as a motor.

Abstract: A hydraulic circuit. The circuit includes a high pressure line and a low pressure line, the pressure in the high pressure line being greater than the pressure in the low pressure line, a hydraulic machine having two ports designed to be connected to the high pressure and low pressure lines, a first of the ports being a hydraulic fluid intake port and the second of the ports being a hydraulic fluid discharge port The circuit includes a sequential connector designed to connect the ports of the hydraulic machine to the high and low pressure lines.

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 is provided. The system includes 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; and a “bypass” connection between a delivery orifice of the auxiliary pump and an unpressurized reservoir. In addition, a first constriction is arranged on the bypass connection, and configured to 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 hydrostatic transmission apparatus for a vehicle having at least two wheels, the second wheel being steerable, may include a main hydraulic pump, two hydraulic motors driving respective ones of the wheels, detection means for detecting that the second wheel is turned by being steered, a first synchronization duct between the first and second motors, and re-feed means for re-feeding the first synchronization duct, and suitable for acting, while the second motor is being fed by the first motor via the first synchronization duct, and when the second wheel is turned by being steered, to inject fluid into the first synchronization duct while limiting the pressure in said synchronization duct to a pressure less than a re-feed pressure that is significantly less than the high pressure of the pump.

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: 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: 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 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 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 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: The circuit comprises a main hydraulic pump (52), two main ducts (50, 54), a booster pump (56), a hydraulic motor (10; 20) which comprises two elementary motors (11, 12; 21, 22) for driving a first displacement member (1, 2), and a second hydraulic motor (30; 40) for driving a second displacement member (3, 4). The second elementary motor (12) is in parallel with the second main motor (30) while the first elementary motor (11) and the second main motor (20) are connected to a feed or discharge additional duct, e.g. via a series link between them. The booster pump (56) is connected to the additional duct, e.g. an interconnection duct (60; 62) for interconnecting the first elementary motor (11; 21) and the second main motor (30; 40). A replenishing valve (70) is suitable for connecting one of the main ducts to a pressure-free reservoir (51) and the circuit further comprises means (72) for preventing said replenishing link from being established on detecting a condition that reveals a spin situation.