Abstract: A hydraulic motor having radial pistons, and comprising a cam, a cylinder block and a distributor. The cylinders of the cylinder block are connected to communication orifices (32A) situated in a communication face of the cylinder block, while the distributor has a distribution face in which distribution orifices (21A, 23A) are provided that are suitable for communicating with the communication orifices for rotating the motor. The cam is provided with a plurality of lobes (50, 50?), each of which has two ramps (51, 52), each ramp corresponding to a distribution orifice (21A, 23A). The edge of each of at least certain communication orifices (32A) has at least one notch (54A, 54B) suitable for establishing a small section of communication with a distribution orifice. The invention applies in particular to hydraulic motors having radial pistons for which the ratio between the number of cylinders and the number of cam lobes is in the vicinity of 1.

Abstract: The circuit includes a main pump, a hydraulic motor, two main ducts, a selector for connecting the main ducts to the main pump or to a reservoir or for isolating them therefrom, a boost duct, and two pressure limiters disposed between the main ducts. A relief valve device that can take up a retention position and a relief position in which it connects one main duct (14, 16) to a relief enclosure can take up its relief position when, with the selector isolating the main ducts from the main pump and from the reservoir, the difference between the pressure in the main duct to which the control duct is connected and a relief pressure higher than the boost pressure changes sign.

Abstract: A hydraulic motor having radial pistons, and comprising a cam, a distributor, and a cylinder block whose cylinders are connected to communication orifices situated in a communication face of the cylinder block. The distributor has a distribution face in which distribution orifices open out that are suitable for communicating with the communication orifices while the cylinder block and the distributor are turning relative to each other. The cam is provided with a plurality of lobes, each of which has two ramps (50), each of which has a convex portion (51) and a concave portion (52). The edge of each distribution orifice has a leading portion (B1) via which communication between the distribution orifice and the communication orifices opens, and a trailing portion (B2) via which said communication closes.

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 hydraulic motor having radial pistons, and comprising a cam, a distributor, and a cylinder block whose cylinders are connected to communication orifices situated in a communication face of the cylinder block. The distributor has a distribution face in which distribution orifices open out that are suitable for communicating with the communication orifices while the cylinder block and the distributor are turning relative to each other. The cam is provided with a plurality of lobes, each of which has two ramps (50), each of which has a convex portion (51) and a concave portion (52). The edge of each distribution orifice has a leading portion (B1) via which communication between the distribution orifice and the communication orifices opens, and a trailing portion (B2) via which said communication closes.

Abstract: A hydraulic motor having radial pistons, and comprising a cam, a cylinder block and a distributor. The cylinders of the cylinder block are connected to communication orifices (32A) situated in a communication face of the cylinder block, while the distributor has a distribution face in which distribution orifices (21A, 23A) are provided that are suitable for communicating with the communication orifices for rotating the motor. The cam is provided with a plurality of lobes (50, 50?), each of which has two ramps (51, 52), each ramp corresponding to a distribution orifice (21A, 23A). The edge of each of at least certain communication orifices (32A) has at least one notch (54A, 54B) suitable for establishing a small section of communication with a distribution orifice.

Abstract: The circuit includes a main pump, a hydraulic motor, two main ducts, a selector for connecting the main ducts to the main pump or to a reservoir or for isolating them therefrom, a boost duct, and two pressure limiters disposed between the main ducts. A relief valve device that can take up a retention position and a relief position in which it connects one main duct (14, 16) to a relief enclosure can take up its relief position when, with the selector isolating the main ducts from the main pump and from the reservoir, the difference between the pressure in the main duct to which the control duct is connected and a relief pressure higher than the boost pressure changes sign.

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: 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 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 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 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 a pressure-free 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 pressure-free 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 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: 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: 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: A hydraulic motor comprises a fixed case, a reaction member secured to the case, a cylinder block mounted to rotate relative thereto about an axis of rotation, and an internal fluid distributor prevented from rotating about the axis relative to the case. The case has a “distribution cover” portion situated around the have respective first and second housings are formed to received a pin which prevents relative rotation while allowing the distribution cover in an axial direction, thereby preventing the distributor from separating from the cover while the motor is being assembled.

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.

Abstract: A drive mechanism (10, 110) for driving first and second displacement members (12, 14, 112, 114) disposed in tandem. The mechanism includes first and second driven sprockets (16, 18; 116, 118) for respective ones of the displacement members, a hydraulic motor (20; 120), and first and second driving sprockets (22, 24; 122, 124) disposed on the casing of the hydraulic motor so as to be rotated thereby. The mechanism also includes first and second chains (26, 28; 126, 128) disposed in a chain case (30; 130), each chain being engaged on a respective driven sprocket and on a respective driving sprocket. The hydraulic motor (20, 120) is a low-speed high-torque motor, having radial cylinders and a rotary casing. The motor is substantially contained in the chain case (30; 130).