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US 4,732,001 AGranted
Hydraulic booster with boost-pressure responsive valve
AssigneeAlfred Teves GmbH
InventorJuan Belart
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AssigneeAlfred Teves GmbH
InventorJuan Belart
Estimating the term…
A braking pressure generator (1,21) for a vehicular hydraulic brake system, wherein a booster piston (15) which is slidable by hydraulic pressure is displaceable in the actuating direction. The booster piston (15) is arranged as a stepped piston with a smaller-diameter portion (16) close to the pedal. The booster piston (15) includes a blind-end bore remote from the pedal in which a master cylinder piston (43) is sealedly guided, wherein the smaller-diameter portion (16) of the booster piston (15) confines an annular chamber (18) diminishing upon brake application. A valve (30) is connected to the annular chamber (18) controllable by the pressure in the pressure chamber (14) of the hydraulic power booster. The valve closes a connection between the annular chamber (18) and an unpressurized supply reservoir (9). A direct connection can be established between the annular chamber (18) and the working chamber (22) by way of the valve (30) and by circumventing a sealing collar.
A braking pressure generator for a hydraulic brake system for automotive vehicles, wherein a booster piston is slidably arranged in a housing and is displaceable in the actuating direction by hydraulic auxiliary pressure, wherein the booster piston is provided as a stepped piston with a smaller - diameter portion close to one end of the housing adapted to be located adjacent a brake pedal, wherein the piston includes a blind-end bore remote from the one end of the housing, wherein a master cylinder piston is sealedly guided in the blind-end bore and forms a working chamber therewith, wherein the smaller - diameter portion of the booster piston confines an annular chamber diminishing upon brake application, wherein a valve which is located in the housing and which is controllable by the pressure in a pressure chamber of the hydraulic power booster is connected to the annular chamber, said valve being operable for closing a connection between the annular chamber and an unpressurized supply reservoir, wherein a direct connection is established between the annular chamber and the working chamber by way of the valve and by circumventing a sealing collar, and wherein a closing element normally sitting close to a valve seat of the valve in the connection between the working chamber and the annular chamber is switched into an operating position of the valve gate by the pressure prevailing in the pressure chamber and by pressure from the master cylinder.
A braking pressure generator for a hydraulic brake system for automotive vehicles, wherein a booster piston is slidably arranged in a housing and is displaceable in the actuating direction by hydraulic auxiliary pressure, wherein the booster piston is provided as a stepped piston with a smaller - diameter portion close to one end of the housing adapted to be located adjacent a brake pedal, wherein the piston includes a blind-end bore remote from the one end of the housing, wherein a master cylinder piston is sealedly guided in the blind-end bore and forms a working chamber therewith, wherein the smaller - diameter portion of the booster piston confines an annular chamber diminishing upon brake application, wherein a valve which is located in the housing and which is controllable by the pressure in a pressure chamber of the hydraulic power booster is connected to the annular chamber, said valve being operable for closing a connection between the annular chamber and an unpressurized supply reservoir, wherein a direct connection is established between the annular chamber and the working chamber by way of the valve and by circumventing a sealing collar, and wherein the valve includes a closing element which is disposed in a piston element displaceable by the pressure from the master cylinder and which is preloaded by a spring against a matching valve seat provided at the piston element.
A braking pressure generator for a hydraulic brake system for automotive vehicles, wherein a booster piston is slidably arranged in a housing and is displaceable in the actuating direction by hydraulic auxiliary pressure, wherein the booster piston is provided as a stepped piston with a smaller - diameter portion close to one end of the housing adapted to be located adjacent a brake pedal, wherein the piston includes a blind-end bore remote from the one end of the housing, wherein a master cylinder piston is sealedly guided in the blind-end bore and forms a working chamber therewith, wherein the smaller - diameter portion of the booster piston confines an annular chamber diminishing upon brake application, wherein a valve which is located in the housing and which is controllable by the pressure in a pressure chamber of the hydraulic power booster is connected to the annular chamber, said valve being operable for closing a connection between the annular chamber and an unpressurized supply reservoir, wherein a direct connection is established between the annular chamber and the working chamber by way of the valve and by circumventing a sealing collar, and wherein the valve includes an annular piston which is displaceably arranged coaxially to a piston and a piston element therein, which annular piston is designed as a closing element and normally kept at a distance to the piston element by a shoulder of the piston.
Dependencies are inferred from the claim text.
Drawings are temporarily unavailable. Open the PDF at USPTO
Master cylinder integrated or hydraulically coupled with booster: part of the system directly actuated by booster pressure
Resilient suspensions of a rigid axle or axle housing for two or
Systems with master cylinder: master cylinder integrated or hydraulically coupled with booster
Vehicle brake control systems or parts thereof
Term ended 24 Jul 2005 (estimated)
USPTO file history isn’t available for this patent, so only indexed dates are shown.
1. Field of the Invention
The present invention relates to a braking pressure generator for a vehicular hydraulic brake system, wherein a booster piston which is slidable by hydraulic auxiliary pressure is displaceable in the actuating direction. The booster piston is designed as a stepped piston with a smaller-diameter portion close to the pedal, and the booster piston includes a blind-end bore in which a master cylinder piston is sealedly guided. The smaller-diameter portion of the booster piston confines an annular chamber diminishing upon brake application. A valve is connected to the annular chamber and is controllable by the pressure in the pressure chamber of the hydraulic power booster, the valve closing a connection between the annular chamber and an unpressurized supply reservoir.
2. Brief Description of the Prior Art
The mode of operation of the brake system according to the present invention is described hereinafter in more detail with reference to the accompanying drawing wherein:
FIG. 1 is a sectional view of the entire brake system and;
FIG. 2 is an enlarged view of the valve of FIG. 1.
Reference numeral 1 in FIG. 1 designates a hydraulic power booster, the construction of which is described in detail in U.S. Pat. No. 4,649,707. Identical parts have been assigned identical reference numerals. The hydraulic power booster 1 can be actuated by a force applied to the brake pedal 2. The hydraulic power booster 1 is connected with an auxiliary pressure source 3 consisting essentially of a pressure accumulator 4 loaded by a pump 6 driven by an electric motor 5. The suction side 7 of the pump 6 communicates by way of a pressure medium filter 8 with an unpressurized supply reservoir 9. Connected to the pressure side 10 of the pressure medium pump 6 is a check valve 11 which prevents a return flow toward the pressure medium pump 6. Connected to the outlet of the check valve is a pressure relief valve 12 which, when the pressure exceeds a specified level, prevents further loading of the pressure accumulator 4 and carries away the volume delivered by the pressure medium pump toward the unpressurized supply reservoir 9.
The hydraulic power booster 1 essentially operates such that when a force is applied to the brake pedal 2, a piston rod 13 connected to the brake pedal 2 is displaced in the actuating direction, which causes a hydraulic pressure to be built up in the pressure chamber 14 of the hydraulic power booster 1 by way of a brake valve which is not shown. The pressure chamber 14 of the hydraulic power booster 1 is limited by a booster piston 15, the booster piston 15 having a portion 16 with a smaller diameter and a portion 17 with a larger diameter. The smaller-diameter portion 16 of the booster piston 15 and the housing confine an annular chamber 18, the volume of which diminishes upon brake application due to two sealing collars 19,20.
Downstream of the hydraulic power booster 1 a tandem master cylinder 21 is connected which comprises a working chamber 22 close to the pedal and a working chamber 23 remote from the pedal. To each working chamber a central valve 24,25 is allocated which upon displacement of the booster piston 15 or a pressure build-up in the working chamber 22 reaches a closing position in which the working chambers 22,23, which are normally in connection with the unpressurized supply reservoir 9, are hydraulically separated from the unpressurized supply reservoir 9. Wheel brakes 26,27,28,29 are connected to the working chambers 22,23 of the tandem master cylinder 21.