Abstract: Hydraulic motor drive apparatus having a cubic capacity selector (16) which has at least two positions, control means for controlling the selector, which means comprise a hydraulic control chamber (18) suitable for being fed with fluid via a control duct (20), and first opposing return means (17). The apparatus further comprises a brake system having a brake release chamber (38) and second opposing return means (39). The control duct (20) is suitable for being connected to the brake release chamber (38), and the first return means (17) are suitable for returning the cubic capacity selector to its large cubic capacity first position when the pressure in said chamber becomes lower than a first threshold pressure, whereas the second return means (39) return the brake means (36) to their braking position when the pressure in the brake release chamber becomes lower than a second threshold pressure, which is itself lower than said first threshold pressure.

Abstract: A replenishing device for a closed circuit comprising at least one hydraulic motor and at least two main pipes which are connected to the pump to provide respectively the feed and the discharge for the motor. The device comprises a replenishing selector suitable for putting the main pipe that is at the lower pressure in communication with a valve which itself communicates with an atmospheric pressure reservoir. The replenishing selector and the valve are united in the same replenishing valve unit having an inlet suitable for being connected to the main pipe that is at the lower pressure, and an outlet which communicates continuously with the atmospheric pressure reservoir. The valve is suitable for causing the inlet to communicate with the outlet when the pressure in said main pipe reaches a given pressure threshold.

Abstract: The tapping circuit forms part of a main fluid circuit which comprises a hydraulic motor having a preferred operating direction and at least two main pipes suitable for communicating with the cylinder block of the motor and constituting respectively, in said preferred operating direction, a feed main pipe and a discharge main pipe. The tapping circuit comprises a single tapping and removal valve connected continuously via a tapping pipe to that one of said main pipes which, in the preferred direction, serves for discharge purposes. This valve serves to replenish the fluid so as to cool it and/or to flush the internal space of the casing of the motor.

Abstract: A hydraulic circuit for the hydrostatic transmission of a vehicle, said hydraulic circuit comprising at least one hydraulic motor, two main ducts, a parking brake having brake means, brake release control means suitable for feeding the brake release chamber from a first brake release fluid source, and means for connecting said chamber to a unpressurized reservoir. The circuit has a single short-circuit and selection valve having two main ports connected to respective ones of the two main ducts, and two selection ports connected respectively to the brake release chamber and to the brake release duct, and control means for controlling said valve, which control means are suitable for causing the valve to take up a first configuration in which the main ports are mutually isolated while the selection ports are interconnected, and for causing it to take up a second configuration in which the main ports are interconnected while the selection ports are mutually isolated.

Abstract: A braking system for braking a rotor relative to a stator, the braking system comprising braking means respectively secured to the rotor and to the stator, a brake piston, return means for returning the piston to its braking position, a braking chamber, and a brake release chamber, which chambers are interconnected via a link duct serving to generate a flow of fluid in an assisted braking situation in which the braking chamber is connected to a fluid feed duct, while the brake release chamber is connected to a fluid return duct. The link duct is equipped with means for limiting the flow of the fluid at least in the direction going from the brake release chamber to the braking chamber.

Abstract: A valve device (10) for at least one hydraulic motor suitable for driving a mass of large inertia. The device includes first and second ducts (12, 14) serving to be connected to respective ones of the two main ducts (feed or discharge) of the motor, and an auxiliary duct (15) connected, for example, to a booster duct. The device can have two configurations, depending on which of the main ducts has the higher pressure, in which configurations the main duct at high pressure is isolated, while the main duct at low pressure is connected to the auxiliary duct. The device includes time delay means (36, 46, 38, 48) suitable for limiting the speed of transition between one and the other of the first and second configurations when the difference between the pressures in the first and second main ducts (12, 14) changes sign.

Abstract: A drive device incorporating a hydraulic motor and a planetary reduction gear. The motor includes a housing in which radial pistons are disposed. The device includes a coupling between the output of the motor and the input of the reduction gear, the reduction gear including a housing in which a planetary reduction gear system is disposed having an output provided for driving in rotation. The housing of the motor and the housing of the reduction gear form distinct enclosures and the device allows circulation of fluid between these housings and for controlling this circulation by limiting this circulation in at least one direction of circulation between the housing of the motor and the housing of the reduction gear.

Abstract: A braking system (S) for braking a rotor (5, 9, 106) relative to a stator (1C, 1′C), said system comprising two series of brake disks (102, 104) secured respectively to the stator and to the rotor and disposed in a disk enclosure (100). The system further comprises a brake piston device (108, 114, 116) urged continuously in the braking direction by resilient return means (118). The piston device is urged in the brake release direction by feeding a brake release chamber (120) with fluid, and it is urged in the braking direction by feeding a braking chamber (124) with fluid. The braking system includes a cooling device for cooling the brake disks (102, 104) by means of fluid flow, which device is provided with a cooling duct (140) branching from the brake release duct (122) which feeds the brake release chamber (120) and communicating with the disk enclosure (100). It is provided with means (148) for limiting the quantity of cooling fluid tapped by the cooling duct (140) from the brake release duct (122).

Abstract: The apparatus comprises two hydraulic motors to which two displacement members in line are respectively coupled. Each of the motors has three main connections, namely one main connection that is common to both of its cylinder capacities, and two main connections, one for each of its two cylinder capacities. The first main connection of the first motor is connected to the fluid feed and the first main connection of the second motor is connected to the fluid return. The two main connections of the motors are interconnected. A selector having at least two positions is connected to the fluid feed, to the fluid return, and to the third main connection of at least one of the motors. For each of the two selector positions, the total cylinder capacity fed by the pump differs.

Abstract: Apparatus for providing drive assistance in a vehicle having a main transmission that is mechanical. The apparatus comprises a hydraulic motor of the type having radial pistons that is powered by a main pump. The pistons can be retracted into their cylinders in a free-wheel configuration of the motor or they can co-operate with the reaction member of the motor when they are in a working configuration. The apparatus comprises means for implementing successive stages of a sequence for causing the motor to pass from its free-wheel configuration to its working configuration. The sequence comprises an initialization stage in which the case of the motor is filled with fluid at a “service” pressure by means of an auxiliary duct and a service duct, and in which the main feed and exhaust ducts of the motor are placed at a filling pressure that is lower than the service pressure.

Abstract: A bearing device (10A) for supporting a wheel and equipped brake including a rotary shaft (5) carrying a rotary plate (9) suitable for supporting a wheel rim, a stationary hub (1C) disposed around the rotary shaft (5), a bearing unit comprising at least one rolling bearing (8A, 8B) supporting the shaft as it rotates relative to the hub, the brake comprising a first series of at least one annular brake disk (28) secured to the hub (1C) and a second series of at least one annular brake disk (30) constrained to rotate with the shaft (5) relative to the hub. The device includes first axial wall element (24) and a second axial wall element.

Abstract: Hydrostatic transmission apparatus for a vehicle having drivable front and rear wheels coupled to front and rear hydraulic motors. A group of motors comprises at least two motors coupled respectively to two wheels situated on either side of the vehicle. The other group of motors comprises at least one motor driving a wheel. The two motors of the first group are dual-capacity motors, each comprising a first elementary motor connected to the pump in parallel with a motor of the second group, and a second elementary motor which is connected in series with said motor of the second group. Two series pipes are thus defined. The apparatus comprises a selection valve connected to the two series pipes and to a port of the pump. This valve can take up a straight-ahead configuration in which the series pipes are isolated from the port of the pump, as well as a left-turn configuration and a right-turn configuration in which the series pipes are connected to said port.

Abstract: A hydraulic motor comprising a cylinder block having at least a first group of radial cylinders, a reaction member mounted to rotate relative to the cylinder block, and an internal fluid distributor having distribution ducts. The motor further comprises a single declutching selector constrained to rotate with the cylinder block about the axis of rotation and provided with a communication duct for each cylinder of the first group of cylinders, the selector being suitable for taking up a first position, in which it is possible to connect the cylinder ducts of said cylinders to the distribution ducts, a second position, in which it is possible to declutch the pistons of the cylinders of the first group by putting the cylinder ducts of said cylinders in communication with a fluid discharge enclosure, and an intermediate transitional position between said first and second positions, and in which said cylinder ducts are connected together via an isolated enclosure.

Abstract: A cylinder-capacity selector for a hydraulic motor having at least two active operating cylinder capacities and comprising having at least two main ducts. The selector includes three ports and distribution ducts of the motor to establish selective communication between the main ducts and the cylinders of the motor. When the selector passes between its first and second stable positions, in at least one displacement direction, an intermediate stage exists that is maintained for a lapse of time, during which all three ports are in communication and the section of at least one of the passages between the first and second ports and between the second and third ports of the selector is constricted.

Abstract: This invention relates to a valve device for at least one hydraulic motor adapted to drive a high inertia mass. The device comprises two principal conduits, respectively intended to be connected to the two principal ducts (supply or exhaust) of the motor. It comprises a communication conduit for placing said principal conduits in situation of communication when the fluid pressures in these conduits are substantially equal and for placing said principal conduits in a situation of isolation in which they are isolated from one another when the fluid pressures in these two conduits are different. The device further comprises delaying means adapted to limit the speed of passage between the situation of communication and the situation of isolation. The communication conduit may include a calibrated restriction. Similarly, the delaying means may include calibrated restrictions.

Abstract: A hydraulic motor (1) comprising a casing (2A, 2B) a reaction member having a reaction profile (4), a cylinder block (6), an internal fluid distributor (16) suitable for putting the cylinders (12) of the cylinder block (6) in communication with fluid feed and exhaust ducts, and a braking system which comprises first and second braking elements (42, 44), constrained to rotate respectively with the reaction member (4) and with the cylinder block (6). The braking system further comprises a brake piston (40) suitable for being displaced axially so as to urge the braking elements into braking contact or so as to enable braking to be released. The brake piston is constrained to rotate with the casing about the axis of rotation, and it has a substantially radial active face, a first brake member (42) belonging to the first braking means being integral with said active face.

Abstract: Each drivable axle of the apparatus has two hydraulic motors, one for each side of the vehicle. The apparatus includes two analogous closed transmission circuits, one for each side of the vehicle. The hydraulic motors of the second axle are dual-capacity motors having three main connections. In each closed circuit, the first main connection of the dual-capacity motor and the first main connection of the motor of the first axle are respectively connected continuously to each of the two ports of the pump of the circuit in question, and each circuit further includes a selector having at least two positions and disposed on interconnection ducts between the pump, the second and third main connections of the dual-capacity motor and the second main connection of the motor of the first axle.

Abstract: A hydraulic motor comprising a fixed case, a cam, a cylinder block having radial cylinders, an internal fluid distributor having distribution ducts, a braking device comprising a dog clutch, and a control piston. The motor is a slow motor having two distinct operating cylinder capacities. An annular space is formed in the case around the distributor beside the radial face of the cylinder block adjacent to the distributor, the first series of teeth of the dog clutch and the control piston are disposed in said annular space, the second series of teeth being secured to the radially-extending face of the cylinder block in the vicinity of the radially-outer periphery of said radially-extending face.

Abstract: Pressurized fluid motor comprising a casing, a cylinder block, a cam, an internal fluid distributor and a selector. The bore of the selector has four grooves. Two of them are communication grooves each connected to a main (feed or exhaust) power duct and to a connection duct, the connection ducts being themselves connected to different groups of distribution ducts. The other two grooves of the bore are branch grooves respectively connected to an additional (feed or exhaust) power duct and to a third connection duct. The slide of the selector comprises at least a first selection groove which is adapted to establish communication between the two branch grooves. By modifying only the shape of the slide, and possibly that of the bore of the additional duct, the selector can provide different functions.

Abstract: This invention relates to a hydraulic fluid circuit comprising a reversible hydraulic motor, a braking device, two principal conduits respectively connected to the two principal supply and exhaust ports of the motor, a principal selector adapted to occupy a position of rest and two active positions in order to select the circulation of the fluid between the principal ports of the motor and the principal conduits to which they are connected. The circuit also comprises an intermediate system of selection capable of occupying a first configuration in which the principal selector is maintained in its position of rest and a second configuration in which the principal selector is allowed to leave its position of rest. The control means of the intermediate system of selection are connected to the braking device so that this intermediate system can pass from its first to its second configuration only when the brake is de-activated.