Abstract: A brake piston comprising a) an open end; b) a closed end; c) a piston cylindrical wall comprising a polymeric material which extends from the closed end to the open end; d) a core member comprising a metallic material located within the cylindrical wall which extends between the closed end and the open end without extending completely to the open end; and wherein the core member structurally reinforces the brake piston. The brake piston may find particular use in a disc brake assembly. The core member may be particularly useful for structurally reinforcing the brake piston when receiving and transferring a brake apply force.

Abstract: A vacuum brake booster includes a housing in which a piston is accommodated, the piston being supported by a cylindrical body sealingly passing through an opening in the bottom and having a key that engages with the return element of the cylindrical recess. A damping element separates the front of the key from the rear of the base supporting the piston and the bead of the membrane.

Abstract: A vehicle brake booster includes a brake input member configured to receive a braking input force and a booster housing divided into a first chamber adjacent the brake input member and a second chamber remote from the brake input member. A poppet valve includes a poppet valve body and a poppet seal, the poppet valve operable to maintain separation between pressure and vacuum during assisted braking and further being operable to enable evacuation of the air from the first chamber through one or more side ports of the poppet valve body upon release of the braking input force and completion of the assisted braking A restrictor element provides a predetermined release speed for the booster. The one or more side ports define a total flow resistance of the poppet valve body which is less than an effective total flow resistance of the poppet valve body set by the restrictor element.

Abstract: A vacuum brake booster includes a movable wall forming a vacuum chamber and a variable pressure chamber in a housing and a valve body connected to the movable wall. A valve mechanism having a vacuum valve for establishing or interrupting the communication between both chambers corresponding to the movement of a plunger and having an air valve for establishing or interrupting the communication between the variable pressure chamber and atmosphere are disposed in an axial hole of the valve body. Atmosphere after the air valve passed flows into the variable pressure chamber through an axial passage and a radial passage formed in the valve body. The axial passage is constituted by a cylindrical inner passage formed at the outer circumference of the plunger by an arc-like flow regulating wall and an arc-like inner circumferential wall portion and an outer passage formed at the outer circumference of the inner passage.

Abstract: The invention relates to a travel limiting element in a brake booster device for a motor vehicle brake system, comprising a pair of longitudinal legs which are connected together via at least one transverse leg, wherein the travel limiting element can be brought into contact with a stop of the brake booster device. In favor of a simple design and cost-effective production, the travel limiting element comprises two dimensionally stable reinforcement braces which extend along the longitudinal legs, and the transverse leg is made of a damping material which surrounds the two longitudinal legs at least in sections.

Abstract: The invention relates to a brake booster with a short actuating travel, in which booster the three-way valve has a moving valve seat borne by a sleeve (54). The movement of this sleeve is controlled by the piston. The invention provides a device that comprises a face (100) that is inclined with respect to the axis of the sleeve in order to allow the sleeve (54) to move gradually.

Abstract: A method for determining whether a panic braking maneuver has been initiated in a vehicle with a brake pedal includes the steps of receiving brake pedal travel data, receiving brake pedal force data, determining a rate of change of acceleration of the brake pedal from the brake pedal travel data, determining a rate of change of acceleration of force applied to the brake pedal from the brake pedal force data, comparing the rate of change of acceleration of the brake pedal with a first predetermined value and a third predetermined value, and comparing the rate of change of acceleration of force applied to the brake pedal with a second predetermined value and a fourth predetermined value.

Abstract: The present invention provides a vacuum booster, which is constructed such that an area with which a cylinder communicates with a port communicating with a reservoir and being open to the cylinder is reduced at high temperature, so that a sufficient reaction force can be transmitted from a piston of a master cylinder to a valve mechanism at an initial stage of the braking operation, thus preventing vibration or noise from being generated in the valve mechanism. At high temperature, stop position, at which backward movement of the piston of the master cylinder is limited by an output member while a valve piston is at a non-operating position, is shifted forwards by a stop position shifting means, thus reducing the area with which the cylinder communicates with the port communicating with the reservoir and being open to the cylinder.

Abstract: A vacuum booster which moderates a retraction speed of a valve seat member to restrain a contact noise between a key member retracting in a unitary manner with the valve seat member and a flange surface of a plunger. The vacuum booster includes a noise restriction device.

Abstract: A pneumatic brake booster for a motor vehicle, comprising a piston (22) mounted between a control rod (24) actuated by a brake pedal and a push rod (34) actuating a piston of a brake master cylinder. Structure for increasing brake boosting during an emergency braking, comprising a cylindrical sleeve (46) mounted in an axially sliding and sealed manner inside the piston (22). The sleeve being retained in the rest position by locking arrangement (58) and released to push away the shutter (56) of a three-way valve and increase the supply of atmospheric air to the booster when the control rod (24) is moved at a speed that is greater than a predetermined value.

Abstract: A negative pressure type booster includes a power piston, a slide valve, and a holding mechanism, among others, and assists a driver during emergency braking. The holding mechanism is adapted to hold the slide valve at a predetermined frontward position, and includes a latch member that is mounted to the power piston in such a manner as to be linearly movable in a radial direction, and a garter spring for biasing the latch member radially inward. The latch member has a hook that can be engaged with and disengaged from a hook provided on the slide valve. When a plunger moves frontward relative to the power piston by a quantity greater than a predetermined value, a push slope provided on the plunger pushes a passive slope provided on the latch member radially outward, whereby the hook of the latch member is disengaged from the hook of the slide valve.

Abstract: In a negative pressure type booster, an atmospheric valve seat is formed on an annular disk of an input member, which disk extends radially outward. The annular disk and an annular diaphragm located frontward of the annular disk and mounted to the input member define an annular atmospheric chamber. The atmospheric chamber communicates with the atmosphere via an air hole formed in the annular disk. The diaphragm is supported from the front by a power piston. The diaphragm is a flexible member. Inner and outer circumferential portions of the flexible member are formed into respective rolling portions for allowing frontward/rearward movement of the input member by means of curviform deformation. An atmospheric control valve portion, which is seated on and separated from the atmospheric valve seat, and a vacuum control valve portion, which is seated on and separated from a vacuum valve seat formed on the power piston, are axially separated.

Abstract: In a negative pressure boosting device of the present invention, upon depression of a pedal at a normal speed, an input shaft 11 and a valve plunger 10 move forward to close a vacuum valve 15 and open an atmospheric valve 16 and a power piston 5, a valve body 4, and an output shaft 24 move forward. In the initial stage of operation, hooks 27c and 31a are not engaged with each other so that a cylindrical member 27 does not move forward, thereby shortening the stroke of the input shaft 11 as compared to a conventional one. Upon rapid depression of the pedal, a press face 10a presses a pressed face 27e so as to deform an engaging arm portion 27b, thereby disengaging the hooks 27c and 31a from each other. The cylindrical member 27 is moved backward by a spring 30 to push a vacuum valve portion 12b so that the atmospheric valve portion 12a is spaced apart from the atmospheric valve seat 14 more rapidly than that of the service braking, thereby increasing the jumping amount and thus rapidly intensifying the output.

Abstract: Vacuum brake booster for motor vehicles comprising a booster housing whose interior is subdivided by a movable wall into a vacuum chamber and a working chamber, a control valve that controls a pressure difference acting upon the movable wall and is accommodated in a control housing that carries the movable wall, said control valve being composed of two concentrically arranged sealing seats and an elastically deformable valve member, wherein the control housing includes a cavity through which a cross member extends and delimits the axial movability of a valve piston relative to the control housing, and the cross member includes at least one projection made of an elastic material in the area where the cross member rests against the booster housing. At least one projection made of an elastic material is provided in the area of points of abutment between the control housing and the cross member.

Abstract: A pneumatic brake booster for use in a motor vehicle having a feeler (42) mounted to slide on a plunger (32) located at the end of a control rod (22) and pivoting key (62) for axially blocking the movement of the feeler (42) with respect to the plunger (32) during a normal brake application and unblocking the movement during an emergency brake application to reduce the length of a plunger-feeler assembly and thus increase the jump phase of an output force.

Abstract: A pneumatic brake booster for a motor vehicle, of the type in which the movements of a control rod (38) are able to determine the openings and closings of at least one axial intake valve (52) which is inserted between a pressure source subjected to the pressure (Pa) higher than the first pressure (P1) and a rear chamber (18) of the booster, and of at least one axial equalizing valve (50) which is inserted between a front chamber (16) and the rear chamber (18), to actuate a moving partition (14) inserted between the front chamber (16) and the rear chamber (18), characterized in that it comprises a tubular element (76) of which axially offset transverse faces (78, 80) comprise first elements (82, 84) for sealing the axial intake and equalizing valves (50, 52) and that the control rod (38) is able to operate via two concentric springs (40, 122) having different stiffnesses.

Abstract: A base 36A of an output shaft 36 is made up of a rod member 36B, and a holder 43 having a bottom 43A. A stop 42 is formed separately from the holder. The holder has a reduced diameter portion 43B, in which an outer coiled spring 41A and an inner coiled spring 41B are disposed, and a piston 40 is disposed rearward thereof, and an increased diameter portion 43D in which the stop is disposed, and a reaction disc 35 is disposed rearward thereof.

Abstract: During a normal brake operation, a brake reaction from a reaction disc is transmitted to a valve plunger through an outer plunger and an inner plunger. During an emergency brake operation, as a valve plunger is driven forward through a given stroke relative to a valve body, a tubular member retracts relative to the valve body. In a servo balance condition, which is reached subsequently, the valve plunger, retracts by an amount corresponding to the retraction of the tubular member, and the outer plunger abuts against a holder. A brake reaction from the reaction disc is transmitted to the valve plunger only through the inner plunger, allowing a booster ratio to be greater and a jumping quantity to be greater than during a normal brake operation. It is possible to increase an output from a brake booster 1 rapidly in immediate response to a quick depression of a brake pedal.

Abstract: A plunger arrangement (46,56,58) for a braking servomotor that has an actuating piston to provide a force to activate a master cylinder. The plunger arrangement (46,56,58) is located in a bore of a movable wall (14) that separates the interior of the servomotor into a front chamber and rear chamber, The plunger arrangement (46,56,58) is connected to a resiliently returned control rod (38) and slides in bore as a function of an input force to define a braking application. The end of the plunger arrangement (46,56,58) is slidingly fitted so as to bias a reaction disk of the actuating rod and transmit a reaction force to the control rod. The plunger arrangement (46,56,58) includes a unidirectional clutch device (56) comprising a key (60) and a sleeve (58) that are slidably mounted on a plunger (46) such that when the control rod (38) is actuated at a given speed the sleeve (58) is locked in the bore of the movable wall (14), independently of the control rod (38), to maintain a braking application.

Abstract: An improvement of a valve plunger 14 used in a brake booster 1. A valve plunger 14 is made up of a rearwardly disposed body 34, and an engaging member 35 mounted on a front portion of the body 34. When a brake pedal is quickly depressed during an emergency brake operation, the engaging member 35 retracts rearward relative to the body 34, whereby the axial size of the entire valve plunger 14 is reduced, thereby increasing the opening of an atmosphere valve during the emergency brake operation as compared with a normal brake operation, allowing an output of an increased magnitude to be rapidly obtained. Thus, the invention allows an output from the brake booster 1 to be rapidly increased in immediate response to a quick depression of a brake pedal.

Abstract: The invention provides a pneumatic servomotor for an assisted braking of a motor vehicle, of the type comprising a unidirectional clutch device, which includes a coaxial sleeve (58), sliding on a plunger (46), and axial-locking means, which are capable of locking said sleeve (58) in an end front axial position, in which it locks the piston (22) independently of the control rod (38), when an input force is applied at a given speed on the control rod (38) integral with the plunger (46), characterised in that the unidirectional clutch device comprises damping means, made of an elastomeric material and interposed between a stop-forming transverse intermediate face (59) of the plunger (46) and an opposite transverse face (76) of the sleeve (58), so as to permit, once the input force is released and when the locking means no longer lock the sleeve (58), the noiseless return of the sleeve (58) to its rear rest position.

Abstract: The invention relates to a pneumatic servomotor for an assisted braking, comprising a rigid casing (1) in which a moving airtight partition wall (2) defines a front chamber (3) and a rear chamber (4), a pneumatic piston (5) travelling with the moving partition wall (2), a plunger (8), housed within the piston (5) and driven by a control rod (7) and controlling the state of a three-way valve (9), force-transmitting means (10, 13, 17, 18, 31), adapted for receiving and transmitting at least one assistance force (Fa), exerted by a front face (51) of the piston (5) when the valve (9) puts the rear chamber (4) under a second pressure (Pa), the plunger (8) including a front section (81) comprising retaining means (18, 31) intended to tie down the front section (81) of the plunger (8) to the pneumatic piston (5).

Abstract: A braking servomotor (10) having a rigid casing (12) with a movable wall (14) location therein to define a front chamber (16) and a rear chamber (18). The movable wall (14) carries a piston (22) that slidably receives an actuating rod (28) for a master cylinder (36). A control rod (28) is sliding located in a bore inside a piston (22) and moved as a function of an input force. The control rod (28) has an end that bears against a plunger (46) that has a finger (52) that biases a reaction disk (32) located at the rear surface of the actuating rod (28) to transmit a reaction force from the actuating rod through the plunger to the control rod. The servomotor (10) is characterised by a unidirectional clutch device (56) that responds to a predetermined speed at which an input force is applied to the control rod (28) to lock the actuating rod in relation to the piston (22), independently, of the reaction disk (32), the plunger (22) and the control rod (28).

Abstract: A tubular member 18 is slidably fitted into a valve body, and is formed with a vacuum valve seat 21. The tubular member 18, a valve plunger 16 and the valve body 3 are maintained in their inoperative positions shown by abutment against a key member 13. A holder 14 is formed with a tapered surface 14a to assist in allowing an elastic deformation of a reaction disc 15. Immediately after the commencement of operation of a valve mechanism 7 as an input shaft 8 is driven forward, the input shaft 8 and the tubular member 18 are maintained in their inoperative positions until a rear end face of a variable pressure passage 28 abuts against the key member 13. The operating stroke of an input shaft 6 can be chosen to be less than the operating stroke of an output shaft 11 while preventing the jumping value from increasing to an excessively high value.

Abstract: A pneumatic brake booster includes a generally cylindrical shaped piston. The piston has a first piston end and a second piston end and defines a chamber at the first piston end and a piston bore at the second piston end separated by an air flow aperture. The piston bore includes a plunger aperture located at the second piston end. A plunger includes a first plunger end and a second plunger end and is movable between first and second positions. The second plunger end is located within the plunger aperture. An air valve has a first valve end and a valve second end and is movable between first and second positions and defines a valve bore for receiving the first plunger end. A collapsing spring is located within the valve bore and is adapted to couple the plunger and the air valve.

Abstract: A first vacuum valve seat 17 is formed on a valve body 3, and a second vacuum valve seat 18 is formed on a tubular member 21 which is slidably mounted on the valve body 3. A lever member 41 is provided between the tubular member 21 and a valve plunger 14, and when the valve plunger 14 strokes through a given stroke or more relative to the valve body 3, the lever member 41 moves angularly to retract the tubular member 21 rearward relative to the valve body 3. When a brake pedal is quickly depressed, the lever member 41 moves angularly to cause an engaging tab 41f to engage an engaging recess 44 formed in the valve body 3, thus retaining the tubular member 21 at a position which is reached as it is retracted rearward relative to the valve body 3. This allows an atmosphere valve 33 to be opened to a greater opening than during a usual operation, allowing an increased output to be obtained rapidly.

Abstract: A pneumatic servomotor for providing an assisted braking of a motor vehicle. The servomotor includes a plunger arrangement with a unidirectional clutch device (56). The clutch device (56) has a coaxial sleeve (58) that slides on a plunger (46) and a substantially ring-shaped key (60) with a given clearance around the sleeve (58). The key (60) is driven by a moving piston (22) in response to a predetermined rate of speed being applied to a control rod (38) by an input force. The predetermined rate of speed causes the key (60) to rock and lock the sleeve (58) with respect to the piston (22) independently of the control rod (38). The unidirectional clutch device (56) comprises at least one locking transverse face (76) for engagement with the sleeve (58). The face (76) is axially directed rearwards from a front end of the sleeve (58) to form a stop for a peg (78) located on the key (60) that extends radially towards the sleeve (58) for axial indexing an end locking position for the sleeve (58).

Abstract: An airvalve assembly for a brake booster includes first and second members movable relative to each other to allow the passage of fluid, and a clip. The clip engages one of the first or second members, and has a spring arm which engages the other of the first or second members to normally position the first and second members relative to each other.

Abstract: A pneumatic brake booster includes a generally cylindrical shaped piston. The piston has a first piston end and a second piston end and defines a chamber at the first piston end and a piston bore at the second piston end separated by an air flow aperture. The piston bore includes a plunger aperture located at the second piston end. A plunger includes a first plunger end and a second plunger end and is movable between first and second positions. The second plunger end is located within the plunger aperture. An air valve has a first valve end and a valve second end and is movable between first and second positions and defines a valve bore for receiving the first plunger end. A collapsing spring is located within the valve bore and is adapted to couple the plunger and the air valve.

Abstract: An airvalve assembly for a brake booster includes first and second members movable relative to each other to allow the passage of fluid, and a clip. The clip engages one of the first or second members, and has a spring arm which engages the other of the first or second members to normally position the first and second members relative to each other.

Abstract: The present invention relates to a brake-power transmission device, especially for motor vehicles, including an actuated input member, an output member to exert a boosting force, especially on a main brake cylinder, and a control valve arranged in a control housing to regulate the boosting force. An axially movable pressure piece is provided in the area of a reaction member. The pressure piece is supported on the input member or the control housing, thereby permitting changes to be made in the power transmission ratio. There is a general need to provide a brake-power transmission device that enables increased boosting only when required and that allows for mechanical sensing of the brake actuation speed so that immediate maximum boost force can be exerted when required without any time delay.

Abstract: The present invention provides a control booster which is capable of appropriately detecting a pedal-operated brake operation during an automatic brake operation. For moving a stop key from a position on a side of a rear-side abutment surface (where a reaction force of a switch acting on a switch operating rod and a spring force of a switch spring are balanced) toward an intermediate position, when the stop key is located on a side of the rear-side abutment surface, only a return force of the spring acts on a contact operating element of the switch. On the other hand, when the stop key moves toward the intermediate position, an abutment portion is separated from the contact operating element (that is, the switch operating rod moves in a direction for separation relative to the switch), so that no load is applied to the contact operating element.

Abstract: A vacuum brake booster (10) has a control valve housing (30) for a control valve (28) actuated by a bar shaped input member (34). A guide sleeve (42) is secured to the control valve housing and has a slot (68) aligned with a vent duct (62) in the control valve housing. A sensing plunger (36) is axially slidable in the guide sleeve by the input member, and a transversely extending stop bar (66) is fixed to the sensing plunger. The stop bar extends through the slot of the guide sleeve and into the vent duct. To improve flow through the vent duct, edges of the slot form axial stops for the stop bar, so that the axial extension of the slot defines the maximum stroke of the sensing plunger. Where the stop bar extends into the vent duct, the vent duct is obliquely oriented towards a working chamber (26), and has an axial extension considerably larger than that of the slot.