Abstract: A brake system, including four hydraulically actuatable wheel brakes. Each wheel brake is assigned in each case one outlet valve which is closed when electrically deenergized. Each wheel brake is assigned in each case one inlet valve which is open when electrically deenergized. The brake system furthermore includes a simulator which is actuatable by a brake pedal, wherein two pressure provision devices are provided for actively building up pressure in the wheel brakes, two brake circuits are hydraulically formed, wherein, in each brake circuit, in each case one pressure provision device is hydraulically connected to two wheel brakes, and wherein two separate on-board electrical systems are provided, and wherein each pressure provision device is fed in each case by one of the two on-board electrical systems.

Abstract: A control device of a bicycle hydraulic brake, comprising a cylinder, a tank, a piston slidably mounted in the cylinder to move between at least one first rest position in which the cylinder and the tank are in fluid communication and at least one second position in which the piston interrupts the fluid communication between the cylinder and the tank, a stop device that acts directly or indirectly on the piston. The cylinder and the tank are filled with hydraulic fluid and the stop device can take up a storage and transportation configuration in which it arranges the piston in said at least one second position.

Abstract: A hydraulic unit for generating brake pressure for a hydraulic brake system, comprising a housing which is produced from a cast blank, wherein the cast blank has at least one receiving cavity which is provided for machining to form a receiving profile for sealingly receiving a connecting piece, which is connected to a fluid container and can be plugged into the receiving profile along a plug-in axis, wherein the housing comprises at least one piston bore for receiving at least one piston, which is driven along a piston bore axis into the cast blank.

Abstract: A hydraulic device is basically provided with a cylinder housing and a reservoir. The cylinder housing includes a cylinder bore. The reservoir is configured to be in fluid communication with the cylinder bore. The reservoir includes a reservoir tank and a lid slidably attached to the reservoir tank.

Abstract: A brake apparatus for a vehicle may including: a cylinder including a supply flow path to supply working fluid of a reservoir and a hydraulic chamber connected to the supply flow path; a piston movably installed in the cylinder, and connected to a brake pedal; an elastic member installed in the hydraulic chamber so as to elastically support the piston; a sealing member installed on the outer surface of the piston so as to be in contact with the inner surface of the hydraulic chamber; and a communication flow path formed on the inner surface of the cylinder along the longitudinal direction of the cylinder, and guiding the working fluid of the hydraulic chamber to the opposite side of the moving direction of the piston, when the piston is moved.

Abstract: A brake-actuating device for a vehicle brake system comprises a fluid reservoir and a master cylinder arrangement. The fluid reservoir has an outlet connection, and the master cylinder arrangement has an inlet connection. The outlet connection of the fluid reservoir and the inlet connection of the master cylinder arrangement, in the connected-together state, define at least one axially overlapping connection region through which a fluid channel for the feed of fluid from the fluid reservoir into the master cylinder arrangement extends. Furthermore, the brake-actuating device comprises a sealing element, which is arranged in the connection region and seals off the latter to the outside, and a filter element for filtering the fluid to be fed to the master cylinder arrangement. The sealing element holds the filter element in a predetermined position in the fluid channel.

Abstract: A cylinder apparatus for a brake may include: a piston configured to reciprocate in a cylinder body; a rod coaxially coupled to the piston; a stopper disposed in the cylinder body with the rod penetrated and inserted into the stopper; and an elastic member disposed between the piston and the stopper and configured to elastically support the piston in a direction away from the stopper. The piston and the rod may be integrally formed by injection molding.

Abstract: A brake system for actuating a pair of front wheel brakes and a pair of second wheel brakes. The brake system includes a reservoir and a brake pedal unit having a housing with first and second pistons slidably disposed in the housing. The first and second pistons are operable during a manual push-through mode by actuation of a brake pedal connected to the brake pedal unit. The first and second pistons are movable to generate brake actuating pressure at first and second outputs for actuating the pair of front wheel brakes and the pair of rear wheel brakes. A first source of pressurized fluid actuates the pair of front wheel brakes and the pair of rear wheel brakes during a non-failure normal braking event. A first electronic control unit controls the first source of pressurized fluid. A second source of pressurized fluid is hydraulically connected to the brake pedal unit and actuates the brake pedal unit to cause movement of the first and second pistons for generating pressure at the first and second outputs.

Abstract: Provided is a master cylinder unit including a communication path that causes a master cylinder and a stroke simulator to communicate with each other. The stroke simulator includes a bottomed tube-shaped simulator piston and a simulator cylinder in which a simulator piston slides. The simulator piston is such that a bottom portion of the simulator cylinder and an opening portion of the simulator piston face each other. The communication path is open over an outer circumferential portion and an inner circumferential portion of the opening portion of the simulator piston, is connected to the bottom portion of the simulator cylinder, and is provided such that the communication path extends upward in a vertical direction from the bottom portion of the simulator cylinder as approaching to a pressure chamber.

Abstract: Disclosed herein is a hydraulic master cylinder body having a bore defined at least in part by a bore wall, wherein the bore wall includes an opening for hydraulic fluid to be passed into the bore, and a piston assembly situated at least substantially in the bore, the assembly having a piston with a piston body and at least one cup seal situated substantially around the piston body, the cup seal situated adjacent to the bore wall so as to be in sealing engagement therewith, and a back-up ring that is situated about the piston body, wherein the back-up ring is positioned to at least partially cover a portion of the cup seal that is adjacent to the bore wall and to prevent at least a portion of the cup seal from contacting the bore wall and the opening for hydraulic fluid during piston actuation.

Abstract: A master cylinder assembly of the type comprises a housing (20) disposed along an axis (A) defining a chamber (22) having a cylindrical shape extending horizontally between an open end and a closed end. A first cylinder (42) and a second cylinder (44) are disposed for sliding movement axially along the axis. Each of the cylinders includes a cylindrical wall (48) defining a cylindrical bore (52). A piston (56) is disposed in each of the cylindrical bores. The cylindrical wall of each cylinder includes a cylinder ramp (70) to define a cylinder ramp shoulder (74). Each piston includes a piston ramp (76) to define a piston ramp shoulder (80). The piston ramp shoulder (80) of each piston and the cylinder ramp shoulder (74) of each cylinder radially engage one another in an assembled position to allow the cylinders (42, 44) and the pistons (56) to abut one another during the sliding movement axially along the axis within the chamber of the housing.

Abstract: A master cylinder includes at least one primary piston and one secondary piston installed in the bore hole of the master cylinder, which pistons are used to create pressure. The primary piston has a body of molded plastic material and is equipped with a functional metallic insert which has the shape of a spherical cap capable of accommodating a push rod.

Abstract: A hybrid patterning apparatus and system for producing thin films on demand from customized patterns is disclosed. The apparatus includes a slot die body integrated with inkjet actuators. The hybrid patterning apparatus may be used in a method of preparing patterned thin film materials.

Abstract: Disclosed is a master cylinder for brake systems including a cylinder body having a bore therein, a first and second piston installed in the bore to move forward and backward, and a first hydraulic pressure chamber and a second hydraulic pressure chamber, the first and second hydraulic pressure chambers being divided from each other in the bore. The master cylinder further includes a pressure regulating channel to connect the first hydraulic pressure chamber to second hydraulic pressure chamber to reduce pressure difference between the first hydraulic pressure chamber and the second hydraulic pressure chamber, and a flow control valve provided in the pressure regulating channel to open and close the pressure regulating channel according to the pressure difference between the first hydraulic pressure chamber and the second hydraulic pressure chamber.

Abstract: A piston unit is disclosed that utilizes an elastic volume to store and release energy with each stroke by varying the hydraulic fluid volumes in and out of the hydraulic unit.

Abstract: A main brake cylinder for a hydraulic vehicle brake system of a motor vehicle is disclosed. The main brake cylinder includes an electric motor that is operated as a generator for decelerating the motor vehicle. For service braking, pressure is applied to a brake circuit by the main brake cylinder and to another brake circuit by a hydraulic pump. In order to reduce a pedal force, a first piston has a smaller piston surface and a second piston only moves if a greater brake fluid volume is required. A preloaded hydraulic accumulator limits an increase in pressure.

Abstract: A vehicle brake system includes a brake pedal unit (BPU) coupled to a vehicle brake pedal and including an input piston connected to operate a pedal simulator during a normal braking mode, and coupled to actuate a pair of output pistons during a manual push through mode. The output pistons are operable to generate brake actuating pressure at first and second outputs of the BPU. A hydraulic pressure source for supplying fluid at a controlled boost pressure is included. The system further includes a hydraulic control unit (HCU) adapted to be hydraulically connected to the BPU and the hydraulic pressure source, the HCU including a slip control valve arrangement, and a switching base brake valve arrangement for switching the brake system between the normal braking mode wherein boost pressure from the pressure source is supplied to first and second vehicle brakes, and the manual push through mode wherein brake actuating pressure from the BPU is supplied to the first and second vehicle brakes.

Abstract: Provided is a body reservoir assembly whose height can be reduced. In the body reservoir assembly, the reservoir comprises: a recessed portion formed on a bottom surface of the reservoir; and a reservoir side connecting portion formed in the recessed portion and connected to a cylinder portion.

Abstract: The present invention relates to a master cylinder assembly in a brake system and a piston stop. The master cylinder assembly comprises one or more piston assemblies. At least one of the piston assemblies comprises a piston (1), a piston stop (2) and a spring (3), wherein the piston stop (2) snaps into the piston (1), and the spring is retained between the piston (1) and the piston stop (2) and placed outside the piston stop (2). According to the present invention, on a circumferential wall of the piston stop (2) are provided deep slots (4) extending axially and running through the thickness of the circumferential wall, and these deep slots open towards one side of the piston stop where it snaps into the piston (1).

Abstract: A vehicular hydraulic-pressure-generation device wherein a first bush compressively deforms due to pressure from a simulator piston that moves when hydraulic pressure produced when a brake pedal is depressed is transmitted into a cylinder part. Said vehicular hydraulic-pressure-generation device thus creates artificial reaction-force characteristics with respect to the position of the brake pedal. The aforementioned first bush has a third elastic modulus, which is smaller than a second elastic modulus, and is provided in parallel with a first return spring. The compressive deformation of the first bush occurs over a second region that overlaps a first region in which compressive deformation of the return spring primarily occurs. This makes the brake pedal move more smoothly, reducing the feeling of incongruity resulting from a V-shaped singularity in the reaction-force characteristics with respect to brake pedal position.

Abstract: A vehicular hydraulic-pressure-generation device wherein a first bush compressively deforms due to pressure from a simulator piston that moves when hydraulic pressure produced when a brake pedal is depressed is transmitted into a cylinder part. Said vehicular hydraulic-pressure-generation device thus creates artificial reaction-force characteristics with respect to the position of the brake pedal. The aforementioned first bush has a third elastic modulus, which is smaller than a second elastic modulus, and is provided in parallel with a first return spring. The compressive deformation of the first bush occurs over a second region that overlaps a first region in which compressive deformation of the return spring primarily occurs. This makes the brake pedal move more smoothly, reducing the feeling of incongruity resulting from a V-shaped singularity in the reaction-force characteristics with respect to brake pedal position.

Abstract: In order to address a problem with the effectiveness of a brake booster device, provision is made for the latter to be produced in the form of hydraulic servo control. In such an instance, a master cylinder (7-10) of a braking circuit (3-4) is provided with a pressure chamber (19) upstream of the braking circuit. This pressure chamber is then subjected to an injection (28) of hydraulic fluid by a pump (34). The pump is operated (39) according to the braking requirements. The servo control comprises a set of moving gear (54) sensitive to these requirements and that work an injection valve (29-30).

Abstract: A brake booster for use in a hydraulic braking system having a brake pedal, a master cylinder, and a hydraulic control unit includes a housing, a screw drive arrangement positioned at least partially in the housing, a motor coupled to the housing for actuating the screw drive arrangement, and a piston assembly positioned in the housing. The piston assembly and the housing together at least partially define a first fluid chamber having an opening for providing fluid communication with the master cylinder, and a second fluid chamber having an opening for providing fluid communication with the hydraulic control unit. The screw drive arrangement is movable relative to a piston of the piston assembly between an engaged position, in which the first fluid chamber is isolated from the second fluid chamber, and a disengaged position in which the first fluid chamber is not isolated from the second fluid chamber.

Abstract: A master cylinder having a primary piston and a secondary piston is described. The secondary piston is realized of plastic material; it is composed of a skirt and an end wall. The forward edge of the skirt is equipped with longitudinal slots intended to cooperate with the resupply seal to resupply the secondary pressure chamber and ensure operation in rest position whenever the brake circuit is in ESP mode. Supply occurs from the supply chamber, which is connected to the brake fluid reservoir.

Abstract: Disclosed herein is a master cylinder for a vehicle. The master cylinder includes a housing, a piston, inlet ports and a seal. The housing has therein a liquid pressure chamber to contain oil. The piston reciprocates in the liquid pressure chamber to control the pressure in the liquid pressure chamber. A front end of the piston has a stepped structure. The inlet ports are provided in the housing so that oil is supplied into the liquid pressure chamber through the inlet ports. The seal is seated into a seating depression which is formed in the inner surface of the housing. The seal opens or closes a flow path of the oil depending on whether the seal is brought into contact with the piston. The oil flows into the liquid pressure chamber along the stepped outer surface of the piston through a space defined between the piston and the seal.

Abstract: A vehicle brake device is provided with a master cylinder, a master piston slidably arranged in the master cylinder, an input piston slidably arranged in the master cylinder to be separated from the master piston and defining a separation chamber, an input piston moving amount detecting section for detecting the moving amount of the input piston, a master piston moving amount calculating section for calculating the moving amount of the master piston based on the moving amount of the input piston, and a contact inferring section for inferring the contact of the input piston with the master piston based on the moving amount of the input piston and the moving amount of the master piston.

Abstract: A dual hydraulic controller apparatus comprises a housing, a first master cylinder disposed at the housing, and a second master cylinder disposed at the housing and coupled to the first master cylinder. The first master cylinder includes a first hydraulic chamber and a first piston disposed in the first hydraulic chamber for reciprocal movement therein. The second master cylinder includes a second hydraulic chamber and a second piston disposed in the second hydraulic chamber for reciprocal movement therein. A first operating member is coupled to the first piston for reciprocating the first piston, and a second operating member is coupled to the second piston for reciprocating the second piston.

Abstract: Disclosed herein is a method of determining the brake pedal actuation force exerted by a vehicle driver on an actuating pedal in an electrohydraulic brake system which includes a brake master cylinder and an electromechanically driven booster stage connected upstream of the brake master cylinder. The brake pedal actuation force sought is determined according to the formula FPed,Bet=FBet,Hz?FVerst by evaluating output signals of a pressure sensor which detects the pressure induced in the brake master cylinder, and of an auxiliary force determining device which detects the boost force made available by the booster stage.

Abstract: A master cylinder apparatus A1 includes a master cylinder 1 and a reservoir 3. The master cylinder 1 transduces an input to a brake operator into a brake fluid pressure. The reservoir 3 includes a fluid supply hole 3a that is connected to the master cylinder 1. A base body 10 of the master cylinder 1 includes a first cylinder hole 11a into which a piston is inserted, a reservoir union port 13a to which the fluid supply hole 3a is connected, and a communication hole 13d. The communication hole 13d has one end opening in a bottom surface of the reservoir union port 13a, and the other end opening in an inner circumferential surface of the first cylinder hole 11a. A center axis O3 of the reservoir union port 13a passes through a position being apart from a center axis O1 of the first cylinder hole 11a.

Abstract: A master cylinder includes a bottomed cylindrical cylinder body, a piston formed into a bottomed cylindrical shape by a forging method and slidably disposed in the cylinder body, and a spring assembly including a spring urging the piston toward an opening side of the cylinder body. A length of a spring of the spring assembly is determined by a retainer which can abut against an inner bottom portion of the piston. An annular groove is formed on the outermost side of the inner bottom portion of the piston by the forging method.

Abstract: A braking system having a master cylinder to which wheel brake circuits (I, II) can be connected, a first piston coupled to a brake pedal, a second piston by means of which the master cylinder is actuated, a third piston actuated by the first piston and connected in a force transmitting fashion to the second piston, a simulation device which gives the driver of the vehicle a pedal sensation, an intermediate space between the second piston and third piston, a pressure generating device which controls the pressure in the intermediate space, a pressure medium reservoir vessel which is under atmospheric pressure and which can be connected hydraulically to the intermediate space, and means for electrically controlling the pressure in the intermediate space.

Abstract: A vehicle hydraulic master brake cylinder assembly (12) having a housing (14) with a cylindrical bore (16) for retaining primary (18) and secondary (20) pistons to define primary (26) and secondary (28) fluid pressure chambers. Primary (42) and secondary (44) reservoir pots are connected with primary (32, 34, 36, 80) and secondary (48, 50) conduits for respectively conveying hydraulic fluid between a fluid reservoir and the primary and secondary chambers. A valve (76) operates by the secondary piston (20) to selectively open and close communication between the primary pot (42) and the primary conduit. Upon closing the valve (76), a primary circuit dead stroke is reduced by allowing initial pressurized fluid to develop and be presented to a primary circuit flow path for the primary conduit (32, 34, 36, 80) prior to the closure of a poppet valve (30) closing communication between the primary pot (42) and the reservoir.

Abstract: In a brake system including a master cylinder and an electrically-driven hydraulic pressure generator with front and rear pistons, when the hydraulic pressure generator cannot be operated and a failure of a first hydraulic system linked to a rear fluid chamber of the generator occurs and makes a first hydraulic system open to the atmosphere, the brake-fluid pressure of a second hydraulic system transmitted from the master cylinder to a wheel cylinder via a front fluid chamber of the generator is used to perform braking. A forward-facing third front cup seal provided at an intermediate portion of the front piston prevents the brake-fluid pressure generated by the master cylinder from leaking out from a front supply port via the rear fluid chamber. At the same time, a stopper prevents the pressure of the front fluid chamber from moving the front piston excessively backward. The braking is accordingly secured by use of the second hydraulic system linked to the front fluid chamber of the motor cylinder.

Abstract: Brake apparatus includes a transmission unit for operatively connecting a brake pedal to a master cylinder, and the transmission unit is a mechanism capable of varying a ratio between an output amount of a push rod connected to a master cylinder and an operation amount of the brake pedal. Further, the transmission unit is constructed in such a manner that, in an initial operation region of the brake pedal, a ratio of the operation amount of the brake pedal to the output amount of the push rod is set to be greater than in another operation region immediately following the initial operation region.

Abstract: A master cylinder having a housing with a bore wherein front and rear pistons are located by return springs to define front and rear chambers. The front and rear chambers are respectively connected by an axial port and a radial port in the housing to a reservoir. Communication of fluid between the bore and reservoir is controlled by a rear center compensation valve that is linked to a front center port compensation valve such that fluid communication between the front and rear chambers and reservoir is controlled by movement of the rear piston in response to an input force with a first and second actuation springs respectively closing the front and rear center port compensation valves to allow simultaneous pressurization of fluid in the front chamber and rear chamber that is supplied to front wheel brakes and rear wheel brakes to effect a brake application.

Abstract: Brake master cylinder (10) for a motor vehicle, of the type which comprises a substantially axial body (12) inside a bore (14) of which is slideably mounted at least one axial piston, of the type in which the bore (14) comprises two seals, front and rear, interposed between the piston and the bore (14), characterized in that it comprises at least one wide groove (66, 68) which is formed in the bore (14) in front of a groove (70, 72) for retaining the front seal, which extends at least in part around the piston, and which communicates with said retaining groove (70, 72) and the hole in the piston, in order to allow resupplies to occur with a high flow rate.

Abstract: In order to address a problem with the effectiveness of a brake booster device, provision is made for the latter to be produced in the form of hydraulic servo control. In such an instance, a master cylinder (7-10) of a braking circuit (3-4) is provided with a pressure chamber (19) upstream of the braking circuit. This pressure chamber is then subjected to an injection (28) of hydraulic fluid by a pump (34). The pump is operated (39) according to the braking requirements. The servo control comprises a set of moving gear (54) sensitive to these requirements and that work an injection valve (29-30).

Abstract: A hydraulic cylinder for a brake system includes a cylindrical body and a piston. The cylindrical body has a receiving space longitudinally defined therein for movably and sealingly receiving the piston. The receiving space is divided into a first chamber and a second chamber diametrically smaller than the first chamber. The piston has a first portion and a second portion. The first portion and the second portion sealingly and movably abut against the first chamber and the second chamber respectively. In a speed reduction stage the first portion interacts with the first chamber, and in an emergency brake stage the first portion and the second portion interact with the first chamber and the second chamber respectively for providing a greater braking force than in the speed reduction stage.

Abstract: A compliance spring is disposed between the brake pedal and the primary piston of a master cylinder, preferably between the push rod and the primary piston of the master cylinder. Selection of the initial spring compression load of the compliance spring, its permitted spring compression travel and its spring constant, allow for both a simplified and fine adjustment of the brake pedal feel per a brake feel index.

Abstract: Provided are a vehicle braking system and a master cylinder which are capable of providing a good pedal feel. A valve-opening pressure for a pressure-reducing valve of the master cylinder is set higher than a hydraulic pressure which is obtained with a pressing force on a brake pedal being 500 N and lower than a hydraulic pressure obtained at a time when a booster reaches a full-load point in case of failure of the booster so as to be specialized for improving pedal feel. Required performance in case of failure of the booster is realized by a pressure-intensifying unit.

Abstract: The present invention relates to a master cylinder arrangement for a motor vehicle hydraulic brake system comprising a housing, in which two adjacent cylinder bores are provided, two piston arrangements, wherein a first piston arrangement is received in a first of the cylinder bores so as to be displaceable along a first bore longitudinal axis and wherein a second piston arrangement is received in a second of the cylinder bores so as to be displaceable along a second bore longitudinal axis, a force input piston, which is connectable or connected to a brake pedal, wherein in accordance with a movement of the force input piston the first piston arrangement and the second piston arrangement are displaceable, wherein the first piston arrangement with the housing delimits a first pressure chamber, which is fluidically connected to a hydraulic brake system, and wherein the second piston arrangement with the housing delimits a second pressure chamber, which is fluidically connected to the hydraulic brake system.

Abstract: Master cylinder assembly (1) for hydraulic control includes a master cylinder body (2) having a longitudinal bore (3). A piston (6) is arranged in the said bore and includes a seal packing (15) separating two chambers (16, 29) adapted to contain a liquid. The piston also includes a recovery conduit (36) connecting the chambers and by-passes the seal packing, and a valve (38). When the piston is in a rest position, an actuator (54) adjusts the position of the valve between an open position opening the recovery conduit and a closed position closing the recovery conduit.

Abstract: A compliance spring is disposed between the brake pedal and the primary piston of a master cylinder, preferably between the push rod and the primary piston of the master cylinder. Selection of the initial spring compression load of the compliance spring, its permitted spring compression travel and its spring constant, allow for both a simplified and fine adjustment of the brake pedal feel per a brake feel index.

Abstract: A master cylinder including a cylinder body having a tubular shape with a closed end; and a piston having one side slidably inserted into the cylinder body and another side that projects from the cylinder body. The piston and the cylinder body define a pressure chamber for generating hydraulic pressure. The master cylinder also includes a protecting member for covering the side of the piston projects from the cylinder body. The protecting member is adapted to extend and contract, and limit backward movement of the piston.

Abstract: A master cylinder includes a housing and a first secondary piston disposed in the housing. The first secondary piston cooperates with the housing to define a first secondary chamber which changes volume as the first secondary piston moves in the housing. A second secondary piston is disposed in the housing and cooperates with the housing to define a second secondary chamber which changes volume as the second secondary piston moves in the housing. A stepped primary piston is disposed in the housing. The primary piston cooperates with the housing to define a primary chamber which changes volume as the primary piston moves in the housing. The primary piston defines an abutment surface which can be driven into abutment with the first secondary piston and the second secondary piston to move the first secondary piston and the second secondary piston. A primary piston spring maintains a restorative force on the primary piston when actuated.

Abstract: A reservoir apparatus for a bicycle brake lever device comprises a master cylinder and a fluid reservoir including first and second reservoirs. The master cylinder has a master cylinder chamber dimensioned for receiving a master cylinder piston therein. The first reservoir has a first reservoir chamber in fluid communication with the master cylinder chamber for supplying a hydraulic fluid to the master cylinder chamber. At least a portion of the first reservoir chamber is disposed below a portion of the master cylinder chamber. The second reservoir has a second reservoir chamber in fluid communication with the first reservoir chamber, wherein the second reservoir chamber includes an air entrainment surface. The air entrainment surface is positioned higher than an upper surface of the first reservoir chamber.

Abstract: According to the plunger-typed master cylinder of the invention, because deformation of seal cups fitted in the hydraulic pressure chambers with the pistons (primary piston and floating piston) inserted is minimized, that is, the deformation of the inner flange being in contact with pistons does not substantially affect the outer flange being in contact with hydraulic pressure chambers when the master cylinder is in operation, it is possible to prevent deterioration in the performance of passing or stopping oil due to the deformation of seal cups and durability.

Abstract: A tandem master cylinder (1) with central valves has ball-shaped valve members (25, 40) with leaf springs (26, 41) serving as valve springs. The ball-shaped valve members (25, 40) can be manufactured of a plastic material, coated with an elastomer. The size of the balls is preferably adjusted to the size of the pistons (4, 5) to allow a maximum flow while ensuring at the same time that the piston walls retain a thickness. The leaf springs (26, 41) have a bowl-shaped body (61), which is shaped like a partial sphere. To avoid an entrapment of brake fluid or a vacuum between the balls (25, 40) and the leaf springs (26, 41), respectively, a central hole (62) has been provided in the bowl-shaped body (61). The leaf springs (26, 41) are equipped with a plurality of tongue-shaped extremities (63) extending radially outward with end portions (64) bent toward the axial side on which the valve members (25, 40) are located.

Abstract: A master cylinder includes a cylinder body, a reservoir connection port formed at a surface of the cylinder body and being in communication with a reservoir, a pressure chamber formed inside of the cylinder body, a reservoir fluid passage connecting the reservoir connection port and the pressure chamber, a valve mechanism accommodated within the reservoir connection port and reducing an amount of fluid flowing in the reservoir fluid passage in a case where the reservoir fluid passage is at a high pressure, and a valve body including a small diameter cylindrical portion and a large diameter cylindrical portion, the small diameter cylindrical portion forming a passage by means of which the reservoir and the reservoir fluid passage communicate, the large diameter cylindrical portion having one end connected to the small diameter cylindrical portion and the other end fixed to the reservoir connection port, the valve body accommodating the valve mechanism.

Abstract: A master cylinder includes primary and secondary pistons both slidably mounted in the cylinder bore of a cylinder. A stopper plate is disposed in the cylinder bore behind the secondary piston. A groove having a larger diameter than the piston sliding surfaces is formed in the inner wall of the cylinder bore at its axially intermediate portion. The stopper plate includes a pair of diametrically opposed flanges having an outer diameter larger than the diameter of the piston sliding surfaces and smaller than the diameter of the groove. The flanges are received in the groove and engageable with a shoulder formed at the rear end of the groove, thereby preventing excessive backward movement of the secondary piston. The stopper plate has a dimension perpendicular to the direction in which the flanges extend and smaller than the diameter of the piston sliding surfaces. Thus, the stopper plate can be inserted into the cylinder bore with one of the flanges located ahead of the other.