Fiat Societa Per Azioni

Centro Ricerche Fiat S.p.a.

Antonino Bertone

Enrico Rivetti

Giuseppe Amedei

Maurizio Cattaneo

Paolo Vannini

Giulio Dotti

Bruno Roggero

Vincenzo Sarti

A motor vehicle provided with servo-assisted controls for the brakes and steering, has an hydraulic system of the type comprising a volumetric pump the input of which is connected to a reservoir, and first and second distributor devices the first of which is associated with the steering control device and the second of which is associated with the master cylinder for control of the brakes. The said second distributor device is formed in such a way as to function also as a pressure modulating valve.

Motor vehicle hydraulic system

A fluid control device for the selective control of at least one group of three movable members each displaceable between a first working position and a second working position, and each having a rest position intermediate between the first and the second working position includes, for each group of three movable members, a group of three hydraulic control units, each control unit being intended to control a respective movable member, and control means for controlling the feeding of a fluid under pressure coming from a feed source to each of the three feed ducts of each group of three control units.

Combined fluid logic control device

A hydraulic servo-assisted braking system for motor vehicles has a master cylinder controlling two independent braking circuits through respective auxiliary cylinders each having an auxiliary piston with a central bore and an associated servo-piston with a stem which closes the said bore upon displacement of the servo-piston by hydraulic fluid pressure of source circuit, separable from the master cylinder, applied to the servo-piston through a common interception valve which is opened to admit the source pressure to the servo-pistons upon movement of either or both of a pair of pistons in a modulator cylinder subjected to the respective hydraulic pressures in the two brake actuator circuits. Failure of one of the braking circuits allows the other to remain operative, while damage to the servo-cylinders allows braking to remain effective through the master cylinder.

Hydraulic servo-assisted braking system for motor vehicles

A hydraulic actuator for a motor vehicle anti-skid braking system, in which the static and dynamic parts of the hydraulic circuit are separated, the actuator having a solenoid valve operated by electrical signals generated by sensors when associated wheels of the vehicle reach an incipient skid state; upon operation of the solenoid valve during braking, pressure to one side of a balanced piston is removed so that it moves to close a valve which cuts off braking pressure to the brakes. A throttle passage allows pressure build up to take place until equilibrium is established across said balanced piston allowing braking to recommence after a time delay.

Hydraulic actuator for a motor vehicle anti-skid braking system

A hydraulic system for feeding a plurality of independent hydraulic servo-operated devices, such as servo-assisted brakes, clutch and/or servo-operated steering, in which a single pump draws fluid from a common reservoir and fluid pressure is automatically distributed by one or more modulating valves to the or each of the devices requiring power at any one time. The or each modulating valve comprises at least one piston in a cylinder, the piston being displaced by an increase in pressure due to displacement of one or more operating member such as brake or clutch pedal, or steering wheel, this controlling the flow of fluid through an axial passage in the piston by controlling its proximity to a valve shutter element and thereby controlling the fluid pressure in a chamber of the modulating valve, which pressure is fed to a control chamber of at least one distributor associated with a servo actuator of one of the servo operated devices of the system whereby to control the operating pressure applied to this.

Hydraulic system for feeding a plurality of independent hydraulic

A servo-assisted hydrodynamic braking system of the type in which brake pedal pressure is used to control a modulating valve which restricts an output line of a pump thereby increasing the pressure in the output line which is connected to the master cylinder of the braking system in such a way as to apply this increased pressure as a servo-assisting pressure, in which the master cylinder and modulating valve are made as a composite assembly and the pressure within the master cylinder part is used to control the modulating valve so that no direct mechanical interconnection between the brake pedal and the modulating valve is needed.

Hydraulic servo assisted braking system

Servo-assisted hydraulic braking system of the type in which brake pedal pressure is reinforced by a pressure dependent thereon and fed to a master cylinder driving piston by a distributor device which is fed with fluid under pressure from a pressure source and control pressure from control chambers defined by plungers within the master cylinder itself, which plungers are displaced directly or indirectly by the displacement of the driving piston of the master cylinder. The distributor plungers are balanced so that for a given brake pedal pressure they feed through a certain reinforcing pressure and then close off the driving piston chamber from the pressure source, locking in the reinforcing pressure so far applied, so that variations in the pressure generated by the pressure generating device are not fed back to the brake pedal via the driving piston of the master cylinder.

Servo-assisted hydraulic braking system

A power assisted hydraulic steering device in which the hydraulic actuators and the control valves are all contained in a common cylindrical housing surrounding a control shaft connectable to the steerable wheels of the vehicle, the actuator comprises an annular piston formed on the control shaft and housed in a cylinder defined between the control shaft and the sleeve. A control rod linked to the steering column is housed within the control shaft, which is hollow, and carries a valve element which cooperates with interior parts of the hollow control shaft to control fluid pressure applied to one side of the annular piston to cause displacement in one direction, or both sides of the annular piston, which has different areas on opposite sides, to cause displacement in the opposite direction.

Power assisted steering

A hydro-dynamic brake system of the type having a volumetric pump circulating brake fluid to a reservoir, and a modulating valve in the output of the pump acting under the control of the brake pedal to constrict the pipeline thereby increasing the pressure at the output of the pump. This pressure is fed to a distributor controlled by a solenoid valve and also receiving an input directly from a master cylinder which is also controlled by the brake pedal. Each wheel has a speed sensor feeding a processing and control circuit which produces an output signal to a solenoid valve which controls various transfer ports of the distributor. The distributor has a series of cylindrical cavities housing pistons which control valves in passages linking the chambers into which each cavity is separated by its piston. These pistons control the flow of brake fluid to the brake actuators so that upon skidding the brakes are released in a rapid but controlled manner, and likewise reapplication of the brakes after skidding is progressive so that there is no 'snatching' which might lead to a loss of control.

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Sant'Antonino (Vercelli), Italy

Antonino Bertone