Abstract: A master cylinder including: a primary chamber; a first piston which is provided in the primary chamber, and has one portion that is moved to the outside of the primary chamber by pressing a pedal; a secondary chamber which is provided to be adjacent to the primary chamber; a second piston which is provided in the secondary chamber, and has one portion that protrudes to the outside of the secondary chamber and is provided to be spaced apart from the first piston at a predetermined interval; and a hydraulic line which connects the primary chamber and the secondary chamber, and is connected with a wheel cylinder, in which the first piston is moved by pressing the pedal, and after the first piston is moved at a predetermined interval, the first piston and the second piston come into contact with each other, and are moved together.

Abstract: Provided is a stroke simulator in which the piston operates smoothly without being inhibited from displacement thereof by the negative pressure generated in the closed space, even if the piston is configured to be displaced so as to close the space in which the elastic member is housed, and to elastically deform the elastic member. A stroke simulator, in which a simulator piston presses a first return spring, which is housed in a bottomed cylindrical portion, from an opening portion side of the cylindrical portion, to cause the first return spring to be elastically deform, and to generate a brake reaction force. When the opening portion is closed by the simulator piston, a brake fluid filled in the cylinder portion is taken into the inside of the cylindrical portion via a flow path leading to the inside of the cylindrical portion from a second cylinder.

Abstract: Disclosed is a variable pedal feeling adjustment device. A pedal simulator includes a simulator block formed with an oil hole connected to a master cylinder through a passage and a bore communicating with the oil hole, a damping housing slidably installed in the bore while being restricted in rotation, a first reaction unit provided in the bore and configured to provide reaction force by being pressurized by oil from the master cylinder, and a second reaction unit supported by the damping housing and configured to provide reaction force by being pressurized by the first reaction unit. An auxiliary simulator includes an auxiliary chamber connected to the passage through a connection passage, an auxiliary piston slidably provided in the auxiliary chamber, and an auxiliary spring to elastically support the auxiliary piston. A control valve is installed to the connection passage to control transfer of hydraulic pressure to the auxiliary chamber.

Abstract: The invention relates to a brake control system for motor vehicles and, in particular, to a hydraulic control system. The invention also applies to hybrid braking systems such as those provided in hybrid vehicles (vehicles propelled electrically and propelled using internal combustion engines) comprising a hydraulically operating braking system which comprises a simulator (3) not mechanically coupled to the brake booster piston (42) and an electric braking system using the electric propulsion motor or motors as electric generators.

Abstract: The invention relates to a brake control system for motor vehicles comprising a brake pedal (1), a brake booster (4), a brake master cylinder (5). The system of the invention further comprises a simulator (3) pneumatically coupled to the piston (42) of the brake booster (4). This simulator (3) receives at least one brake command from the brake pedal (1) and in return establishes a pressure difference between the front chamber (40) and the rear chamber (41) of the booster so as to cause the piston (42) to move.

Abstract: A power brake apply system includes a master cylinder having a piston for generating fluid pressure within a braking circuit. A boost valve assembly is mounted adjacent the master cylinder and carries a slidable spool that selectively closes off a normal path of communication between a fluid reservoir and the boost chamber of the master cylinder in response to the manual actuation of the master cylinder's piston as effected through a pressurized braking circuit. After closure of communication between the reservoir and the boost chamber a power fluid supply is opened to the boost chamber to provide power assist in the actuation of the master cylinder's piston.

Abstract: A fluid pressure control device has a sliding member fitted in a housing for switching over the connection and the disconnection between an input port connected to a fluid pressure supply source, an output port connected to a fluid pressure operated device and a release port connected to a reservoir; a reaction chamber for generating a fluid pressure urging the sliding member in a retracting direction; an urging piston operatively connected to the rear end of the sliding member; an input piston operatively connected to an operation member; and a pressure chamber formed between a back surface of the urging piston and a front surface of the input piston; wherein a first pressure receiving area of the sliding member exposed to the reaction chamber is set smaller than a second pressure receiving area of the urging piston exposed to the pressure chamber, and the second pressure receiving area is set smaller than a third pressure receiving area of the input piston exposed to the pressure chamber.

Abstract: A hydraulic booster for slip-controlled brake systems, including a booster piston (1) arranged in a booster housing (11) and confining a booster chamber (4). A braking pressure control valve is provided whose control part (12) is actuatable by a lever mechanism (13) as a function of the piston of the control part (12). An actuating piston (2) is displaceably guided in the booster piston (1) and is positioned by way of a push rod which cooperates with the lever mechanism (13). To provide a hydraulic booster to realize boosting factors of any desired size, both of constructional and strength-minimizing nature, an annular surface (24) is formed the stepped actuating piston (2), on the side of the push rod (22) and is larger than the total area of any opposing annular surfaces, subject to the booster chamber pressure to create a net force acting to oppose the push rod force and allow setting of the boosting factor by adjustment of the area of the annular surface.

Abstract: A servo-assisted master cylinder assembly for a vehicle hydraulic braking system has a tandem master cylinder with primary and secondary pistons operative to pressurise primary and secondary pressure spaces for primary and secondary brake circuits. A servo chamber is defined behind the primary piston, and pressurisation of the servo chamber from a source of pressure fluid is controlled by a valve in response to an input force applied to the primary piston. The valve comprises a spool operated solely by pressure in the primary space and a bias force from servo pressure in a bias chamber and a spring. The secondary piston has a smaller effective area than the primary piston, so that the pistons are in abutment in their retracted positions. To reduce pedal travel, one of the brakes of the primary circuit can be supplied from the servo chamber instead of the primary pressure space.

Abstract: The invention concerns a hydraulic amplifier for a braking system incorporating a body (10, 110), a first component (18, 124) capable of being displaced in the body (10, 110) under the effect of the operation of a brake pedal, between a first position causing a first chamber (16), joined to a braking circuit, to communicate with a low pressure reservoir (44, 138), and isolating this chamber (16) from a high pressure source (32, 130), and a second position isolating the chamber (16) from the low pressure reservoir (44, 138) and causing it to communicate with the high pressure source (32, 130), characterized in that it incorporates a second chamber (12, 112) formed in the body (10, 110), a circuit (42) causing this second chamber (12, 112) to communicate with the low pressure reservoir (44, 138), and a valve means (34, 116) responsive to the pressure of the high pressure source (32, 130) normally closing this circuit under the effect of the pressure of the high pressure source (32, 130).

Abstract: Hydraulic assistance device incorporating a casing provided with a bore in which a first piston is mounted so as to slide, the piston being able to move under the effect of a brake pedal between a first position, isolating a first chamber which is joined to the brakes of the vehicle, from a source of high pressure fluid, and a second position, causing the first chamber to communicate with the high pressure source, the device also incorporating a second chamber formed in the casing, a passage joining the first and second chambers and a valve mechanism in the passage in such a way that the passage is normally closed, under the effect of the pressure in the second chamber, characterized in that the device incorporates a second passage, causing the second chamber to communicate with a low pressure reservoir, and a second valve mechanism in the passage, the valve mechanism being sensitive to the pressures in the first and second chambers in such a way that the passage normally remains closed during the operation o

Abstract: An assistor for reducing stepping force of a clutch pedal, in which a push rod is inserted into an assistor casing freely movably in the axial direction, a casing outside end of the rod is interconnected to a clutch pedal, a casing inside portion of the rod is provided with a piston which divides the casing into first and second chambers, the first chamber intercommunicates with atmosphere, the second chamber intercommunicates freely changeably with atmosphere and a negative pressure source through a change-over valve mechanism, and the piston is interlocked with the change-over valve mechanism through the means of a negative-pressure setting spring so that negative pressure for reducing stepping force can be fed into the second chamber according to a shifted length of the rod.

Abstract: In a master cylinder assembly the pressure spaces in advance of pedal-operated pistons of two separate master cylinders are interconnected by a transfer passage, and each master cylinder incorporates a boost chamber to which hydraulic fluid from a pressure source is admitted to act on the piston and augment the force applied to the piston by the pedal when the master cylinder is operated. Each master cylinder incorporates a control valve having a valve spool which is normally urged by a spring into a retracted position to close a transfer port providing communication between the pressure space and the transfer passage and to close an inlet port to cut-off communication between the pressure source and the boost chamber.

Abstract: The invention provides a power assisted hydraulic control system suitable for actuating clutches and brakes. The system incorporates a master cylinder having a master piston therein defining a control chamber, a hydraulic power assistance unit, and a distributor adapted to connect, by means of a slide valve, the power assistance unit with the hydraulic receiver controlling the brake or clutch unit. The distributor comprises a slide-valve having a plunger one end of which is subjected to the pressure in the control chamber and the other end of which is subjected to the pressure in the receiver.A bypass channel links the control chamber of the master cylinder to the pipeline connecting the operating port of the distributor to the receiver. The bypass channel has a bypass valve controlled by a spring which opens in the event of failure of the power assistance to permit manual operation by the master piston.

Abstract: A toggle assembly for vehicles or cars comprising a relay cylinder mounted on an end plate including a booster cylinder and an output cylinder, a control chamber arranged in coaxial relation to the relay cylinder, a control valve for controlling a gas by a hydraulic pressure of a master cylinder, said valve being arranged in operable association with the control chamber, and a booster piston disposed in the booster cylinder and in operable association with the controlled gas, wherein said end plate is provided with a shell for said booster cylinder as an integral piece, said shell is integrally provided with a first compressed air passage having its one end being open in the back chamber of the booster cylinder for the booster piston and its other end passing through said end plate and being open at the end of a relay valve body, and a second compressed air passage is provided to extend from a casing for said control chamber, said second passage having its one end in communication with the other open end of s

Abstract: A brake force servo-device, especially for motor vehicles, with a control piston, selectively actuatable preferably by a brake pedal, which cooperates with a connecting valve connected with a pressure medium source and which is operable to displace a flow medium out of its cylinder space for the actuation of the connecting valve; a working piston is thereby actuated by the pressure controlled by the connecting valve, whereby the control piston is constructed as one-piece control piston having an annular step and is sealed off, on the one hand, within the area of its entry into the brake force servo-housing and, on the other, in proximity of its end face which projects into a working pressure space; the control piston thereby abuts at the working piston present in the working pressure space while the connecting valve is actuated by the flow medium displaced by the annular-shaped step of the control piston out of the annular space which is formed between its two bearing places.

Abstract: The invention relates to a hydraulic control, particularly for automobile brake systems having two separate independent brake circuits, in which a master cylinder comprises a first chamber in which pressure is controlled by the driving-in of a master piston under the action of a brake pedal, the first chamber forms a part of a first hydraulic closed system comprising a first brake circuit, the master cylinder also has a second pressure chamber forming part of a second closed system comprising a second brake circuit. The second chamber is adapted to be fed by a source of fluid pressure and the master cylinder is provided with a plunger the opposite faces of which are respectively subjected to the pressures of the two closed systems. The master piston is disposed in the first chamber coaxially with the plunger in such a manner as to permit mechanical intervention in the event of hydraulic failure in the first closed system.

Abstract: A hydraulic brake booster includes a housing 12 with a first chamber 40 and a second chamber 42. An input member 54 extends into the first chamber 40 and is exposed to the second chamber 42. The input member is movable within the first chamber 40 to increase fluid pressure within the second chamber 42 and this fluid pressure operates a control valve 90 to communicate fluid pressure to the first chamber 40. The fluid pressure in the first chamber 40 acts against the input to bias the same toward the second chamber 42. An output member 70 is movable in response to the fluid pressure within the second pressure chamber 42 to actuate braking.

Abstract: The object of the invention is a synchronized hydropneumatic control of clutch and gearbox.In accordance with the invention a hydropneumatic servomotor clutch control has been provided which includes a jack the piston of which is assisted by a pneumatic motor and a master cylinder which feeds the said jack with hydraulic fluid and controls the feed of air to the said motor, characterized in that the control chamber of the said jack is connected to the hydraulic circuit for locking/unlocking the gearbox, the feed to the said circuit being carried out through a valve mounted in the piston. The admission of the hydraulic fluid from the master cylinder having as its effect during a first period the closing of the said valve, thus interrupting the admission of fluid into the said chamber, then the causing of the transfer of the fluid contained in the latter towards the circuit for the gearbox which becomes unlocked in synchronism with the clutch.Application to controls of clutch and gearbox of vehicles.

Abstract: A hydraulic control system for a brake device comprises independent first and second brake circuits, the first circuit communicating with a first chamber pressurized by movement of a master piston actuated by a brake pedal, and the second circuit communicating with a second chamber whose pressure is dependent on that of the first and is developed by an assistance circuit, the second chamber being separated from the assistance circuit by a piston.

Abstract: Disclosed is a hydraulic brake system for vehicles having a separated-type hydraulic fluid pressure amplifier, such as a hydraulic air servo or a hydraulic vacuum servo. This hydraulic brake system includes a brake master cylinder and said fluid pressure amplifier comprises a hydraulic piston and a control piston, which are moved by the pressure of working fluid from said master cylinder, and a power piston which is moved by the air pressure introduced by the action of the control piston. This hydraulic brake system further includes means for resiliently expanding a fluid passage provided in a part of the hydraulic passage between the brake master cylinder and the portion of the hydraulic fluid pressure amplifier in which the working fluid from the master cylinder is applied to said hydraulic piston and said control piston.

Abstract: In a hydraulic brake booster, wherein a body, to which is coupled a master cylinder, is provided with a projecting portion extending outwardly towards the master cylinder; a power piston adapted to operate the piston of the master cylinder extends through the projecting portion to define a working chamber positioned on the side remote from the master cylinder; a pressure chamber, to which is introduced a pressure fluid from a pressure source, is provided in the middle portion of the body; and a first valve which is normally closed for controlling the communication of the pressure chamber with the working chamber and a second valve which is normally open for controlling the communication of the working chamber with a reservoir are operated by means of a valve stem member and an input shaft adapted to operate the valve stem member; the improvement in which a stop slidingly provided within the pressure chamber and adapted to receive pressure from the pressure chamber in the direction opposite to the moving direc