Alfred Teves Gmbh

Guenter Trach

Wolfram Seibert

Norbert Ocvirk

Juergen Schonlau

Juan Belart

Otto Determann

Horst P Becker

A hydraulic brake system for automotive vehicles with a master brake cylinder (1) connected to an unpressurized reservoir and with a brake line (13, 14) connected to a working chamber (4, 5) of the master brake cylinder and leading to pressure control valves of a brake slip control device (40). The pressure control valves are followed by at least one wheel brake (18, 19) with the working chamber (4, 5) of the master brake cylinder (1) being connectable to a pressure medium source (29) upon the start of the brake slip control device. To ensure that in brake systems of different vehicle types, the wheel brakes of which have clearances differing in size, the same master brake cylinder can be used without the master brake cylinder having an undesired long pedal travel and thus a great overall length. This is achieved in that, upon the onset of the application of the brake pedal (3), a pressure medium amount coordinated with the clearance of the brakes can be suppled from the pressure medium source (29) to the brake cylinders of the wheel brakes (18, 19).

Hydraulic brake system for automotive vehicles

A hydraulic brake system is described including a tandem master cylinder whose working chambers are connected by separate brake lines to pressure control valves of a brake slip control apparatus, having the wheel brakes connected downstream of the control valves. A pump unit including a pump communicates with the brake lines through pressure lines and non-return valves. Upon activation of the brake slip control apparatus, the drive of the pump is activated whereupon the pump feeds pressure fluid by way of the non-return valves into the brake line and the working chamber of the master cylinder. The fluid is under a pressure which is in excess of the maximum braking pressure attainable by actuation of the tandem master cylinder. For the purpose of pressure control, the tandem master cylinder includes central valves designed as control valves, by virtue of which the pressure in the working chambers is kept at the pressure level predetermined by an actuating force at the brake pedal.

A hydraulic brake system comprising a pedal-operated brake booster (5), which is connected with the master cylinder (3) and includes an auxiliary pressure supply system (13), a booster piston (4), and a booster chamber (7) wherein an auxiliary pressure is established which is proportional to the foot pressure (F). The hydraulic brake system is provided with wheel brakes (14,15,16,17) connected to the master cylinder (3), a filling stage cylinder (18) is provided which displaceably houses a two-stage piston (20). A pressure chamber (21) is arranged in front of the large stage (83) of the two-stage piston (20) and a filling chamber (22) is arranged in front of the small stage (84) of the two-stage piston (20). In this arrangement, the filling chamber (22) communicates with one of the working chambers (26) of the master cylinder (3) and/or a brake line (28) by way of a pressure line (25). The booster piston (4) plunges into an annular chamber ( 65) arranged between the master cylinder (3) and the brake booster (5). The annular chamber (65) communicates with the pressure chamber( 21) of the filling stage cylinder (18), on the one hand, and with the supply reservoir (55), on the other hand. Connected into the pressure medium path (24,80) from the annular chamber (65) to the supply reservoir (55), to this end, is a valve (79) operable by the pressure in the booster chamber (7). In one of its positions, the valve (79) blocks the pressure medium passage towards the supply reservoir (55). Thus, upon the braking operation, the valve (79) permits the pressure medium to flow from the annular chamber (65) into the pressure chamber (21) of the filling stage cylinder (18) and in its other position the valve (79) connecting the annular chamber (65) with the supply reservoir (55).

Hydraulic brake system

A braking pressure generator consists of a hydraulic brake booster (2) actuatable by a brake pedal (16) and of a master brake cylinder (1) whose master cylinder piston (19) is actuatable by a booster piston (14) pressurizable with an auxiliary hydraulic pressure. The booster piston (14) is guided sealedly and axially displaceably in the bore of an annular secondary cylinder piston (41) which, with a front face (52), confines the booster chamber (13) and which, with its stepped surface area (51), confines a secondary cylinder chamber (44) communicating with a pressure chamber (22) of the master brake cylinder (1) via a pressure line (46). In the brake actuating direction, the secondary cylinder piston (41) is supported at a stop ring (48) of a connecting rod (20) between the booster piston (14) and the master cylinder piston (19). In case of an auxilary-pressure-assisted brake application the secondary cylinder piston (41) supplies pressure medium into the pressure chamber (22), thus a smaller actuating travel resulting at the brake pedal (16). If the auxiliary pressure is lacking upon a brake application, the secondary cylinder piston (41) will remain in its rest position and a sufficient braking action will be achievable by means of the master cylinder piston (19) smaller surface actuated alone.

Braking pressure generator for an automotive vehicle's hydraulic brake

An auxiliary-energy-supplied brake slip control system of a vehicular hydraulic brake system with a brake-pedal-operable master cylinder arrangement (12) and with auxiliary energy supply into the working chamber (16) of the master cylinder. The master cylinder piston (23) portion facing the working chamber (16) is enclosed by a sleeve (58) which is longitudinally displaceable with respect to the master cylinder piston (23) and the master cylinder bore (63). The master cylinder piston (23) having radially extending projections or a collar (66) which, in the brake release phase, rests at the working-chamber-side front face of the sleeve (58) and moves the same back into its initial position. The booster-side front face of the sleeve (58) confines an annular space or a chamber (69) provided in the master cylinder housing and communicates with the booster chamber (21) by way of a pressure line (64). Thus in case of a defective hydraulic brake booster (11) the sleeve (58) remains in its initial position and only the cross-sectional surface of the master cylinder piston (23) being effective, which provides abrupt change in ratio.

Auxiliary-energy-supplied brake slip control system of a vehicular

A hydraulic brake system with slip control comprising a master cylinder (2) pressurizable by a hydraulic power booster (1). A booster sleeve (52) is provided which annularly encloses the booster piston (4), and which is slidably accommodated in the booster housing. The sleeve's end face directed towards the pressure chamber (10) of the booster (1) is applied by the pressure in the pressure chamber (10), while an annular chamber (59) filled with pressure medium and connected to a brake circuit (32) is constituted between the booster sleeve (52) with its head portion (61) and the bore (60) in the booster housing. The booster sleeve (52) is coupled to the booster piston (4) by way of a circlip (53) such that, on movement of the booster piston (4) in the direction of brake actuation, the booster sleeve (52) and the booster piston (4) will displace uniformly. On failure of the booster (1) and displacement of the booster piston (4) exclusively by way of the brake pedal (8), the booster sleeve (52) will remain in its initial position which brings about an abrupt change in ratio.

Hydraulic brake system with slip control

For attaining an abrupt change in ratio, in a slip-controlled brake system for automotive vehicles, the chamber (11) of a fast-fill cylinder (4) is connected to a plunger chamber (41) of the braking pressure generator (1) which is acted upon by the booster piston (40), while the pressure line (7) leading from the plunger chamber (41) to the fast-fill cylinder (4) contains a pressure-controlled directional control valve (8) governing a pressure-fluid conduit to the pressure-supply reservoir (31). The annular chamber (50) of the fast-fill cylinder (4) is connected by way of a return line (55) to the pressure-supply reservoir (31) and with the prechamber (18) of the master cylinder (15) by way of a pressure line (56), while a pressure-controlled two-way/two-position directional control valve (9) with a non-return valve connected in parallel thereto is arranged in the return line (55). Upon failure of the auxiliary-energy supply system (2), the stepped piston (12), the valve (8) and the piston (51) of the intermediate member (39) remain in their inactive position so that the pressure build-up in the brake circuits (36, 37) is affected through the pistons (32, 33) exclusively.

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Offenbach, Germany

Guenter Trach