Abstract: An electromagnetic valve for controlling a passage for a flow of fluid or for a difference in the pressures between an inlet (48;56) and an outlet (56;48), comprises a body (10;16;46) on which is arranged a solenoid coil (22), a bore (26) in which is slideably mounted valve member (30) progressively displaceable in response to actuation of the solenoid coil (22) between a first position and a second position. The valve member (30) and the body (46) comprises cooperating valve surfaces (54;62) defining the passage. One valve surface (62) has in axial section a variable profile so that the area of the passage, in a radial section is a predetermined function of the intensity of the current applied to the solenoid coil (22).

Abstract: The invention relates to a rotary hydraulic distributor comprising a primary rotary element (3) coupled to an actuating device and connected for rotation with a valve rotor, a secondary rotary element (5) coupled to a driven device and connected for rotation with a valve stator, the valve stator and the valve rotor mutually cooperating to control a double acting servomotor of the driven device, a limited relative angular displacement being permitted between primary and secondary elements (3, 5) on either side from a central rest position, and a reaction mechanism being provided in order to bias the primary element (3) toward the central rest position. According to the invention, the reaction mechanism consists of a pair of independent substantially U-shaped pistons (7) able to tilt within respectively one bore (12) of a pair of bores symmetrically provided in secondary element (5), the legs (15) of U-shaped pistons (7) engaging and biasing opposite radial ends (4) of primary rotary element (3).

Abstract: The hydraulic system for a servo steering of a motor vehicle, incorporates a main valve mechanism producing the assistance pressure (Pa) applied to a hydraulic assistance device (12) and including a pair of parallel fluid circuits between a source (14) of pressurized fluid and a reservoir (16), each fluid circuit comprising at least two restrictions (1,2,1',2') capable of being modulated by a rotor mechanism (10) cooperating with a stator mechanism (11), the junction point of the restrictions of each circuit being connected to a respective chamber of the hydraulic assistance device (12) and a secondary valve mechanism producing the reaction pressure (Pr) applied to the steering wheel shaft and including a second pair of parallel fluid circuits between a source (24) of pressurized fluid and a reservoir (16), each of the fluid circuits comprising at least two restrictions (3,4,3',4') capable of being modulated by the rotor mechanism (10) cooperating with stator means, the rotor mechanism (11) cooperating with t

Abstract: The relief valve issued for controlling the pressure of a hydraulic fluid within a first duct 30 opening into a bore 14,16 provided in a body 10, a communication between the first duct 30 and a second duct 34 connecting a primary hydraulic circuit under pressure to the bore 14,16 being provided in rest position of a valve member when the pressure within the first duct 30 is lower than a threshold determined by the preload of resilient mechanism urging the valve member in rest position, the communication being interrupted when the pressure in the first duct 30 sensibly reaches the threshold. An increase of the pressure in the first duct beyond the threshold results in providing a communication between the first duct 30 and a third duct 38 connected to a low pressure circuit.

Abstract: The present invention relates to a tandem rotary master-cylinder for a vehicle brake circuit comprising a body (10;102) in which a first vane (20;114) is mounted for rotation in response to rotation of an input shaft (12;100) in order to generate pressure in a first working chamber (18;126) formed in the body (10;102) and delimited in part by the first vane (20;114).According to the invention the master-cylinder further comprises a second vane (30;120) rotatably mounted in the body (10;102) and delimiting with the first vane (20;114) the first working chamber (18;126) the second vane being rotatable in response to rotation of the first vane (20;114) to generate pressure in a second working chamber (62;128).A rotary master-cylinder with braking assistance is also described.

Abstract: A hydraulic pressure generator comprises a body in which is formed a bore, at least one piston mounted slidably in the bore, an annular sealing mechanism located in the bore, and the piston being slidable from a rest position during operation of the generator to cooperate with the sealing mechanism and divide the bore into a working chamber connectable by an output passage to a hydraulic actuator. A refill passage is connected to a source of hydraulic fluid. The output passage is formed in part between a first surface fixed in the bore and a second surface formed on a member mounted in the bore.

Abstract: Recirculating ball mechanism comprising a body (10), an actuator shaft (16) rotatably mounted within the body (10) and turnable in response to rotation of an input shaft (12), an output piston (18) slidably mounted in the body (10), a bore (22) within the output piston (18) in which is received an end (26) of the actuator shaft (16), the bore (22) having an internal threaded surface (24), the end (26) of the actuator shaft (16) being formed with a threaded surface (28), a series of balls (30) located between the two threaded surfaces (24, 28) so as to operatively connect the actuator shaft (16) to the output piston whereby a given rotation of the actuator shaft (16) produces an associated displacement of the output piston (18) in the body (10), and mechanism (42, 44) for recirculating the balls (30) to a point of origin in the thread (28) formed on the actuator shaft (16) characterized in that the thread (28) comprises at least one closed loop (40) extending around the circumference of the actuator shaft (16)

Abstract: A shock absorber comprises a tubular working cylinder (12) to be mounted on a suspended part of a vehicle, with a piston rod assembly (26) received slidably in the working cylinder (12) having an end (28) to be mounted on a fixed part of the vehicle. The piston rod assembly (26) has at its free end a piston member (40) cooperating with the working cylinder (12) to divide the interior thereof into an upper (52) and a lower working chamber (50), with a valve mechanism in the piston member (40) to permit controlled two-way flow between the upper and lower working chambers (52, 50). A mass (58) is mounted in the shock absorber and displaceable in response to a predetermined acceleration of the shock absorber from a first position in which the mass closes a passage (56, 54, 90) between the working chamber (52) and a reservoir (50; 22), and a second position in which the passage (56, 54, 90) is open.

Abstract: Variable ratio steering mechanism comprising a body in which is rotatably mounted an input shaft, a drive shaft having a longitudinal axis, and coupled to the input shaft so as to be rotatable therewith, an output member slidably mounted in the body, a screw mechanism connecting the drive shaft and the output member so that rotation of the drive shaft produces a corresponding displacement of the output member in the body, characterized in that the drive shaft is axially slidable with respect to the input shaft, the steering mechanism further comprising a displacement mechanism to selectively displace the drive shaft axially with respect to the input shaft, the displacement mechanism comprising a screw connection between the drive member mounted in the body.