Alfred Teves Gmbh

Itt Industries, Inc.

Wolfram Seibert

Norbert Ocvirk

Juan Belart

Juergen Schonlau

Guenter Trach

Jochen Burgdorf

Lutz Weise

Helmut Fennel

Ivica Batistic

Joachim Maas

Hans W Bleckmann

Otto Determann

Horst P Becker

Klaus-Dieter Blum

Guenther Trach

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 brake system provided for automotive vehicles with front wheel drive or with rear wheel drive has a dual-circuit braking pressure generator (1) and diagonally connected wheel brakes. There is provided an auxiliary-pressure-supply system (5) with a hydraulic pump (6) which is switched on during brake application or when there is an excessive traction slip. In the brake slip control phase an auxiliary pressure is built up by an auxiliary pressure control valve (9), in the traction slip control phase an auxiliary pressure is built up by a 2/2-way valve (10). By separating valves (15, 16) the pressure medium path to the non-driven vehicle wheel (HR, HL) is locked in the traction slip control phase and, via inlet valves (EV.sub.3, EV.sub.4), pressure medium is directly fed from the auxiliary-pressure-supply system (5) into the driven wheels (VL, VR). Connected in parallel with the inlet valves (EV.sub.1, EV.sub.2) connecting the braking pressure generator (1) with the wheel brakes (17-20) is one non-return valve (13, 14) each of which can open toward the braking pressure generator (1).

Brake system with control of brake slip and traction slip

A slip-controlled hydraulic brake system which comprises a master cylinder and an auxiliary-pressure supply system is equipped with a travel-responsive switch actuatable by a piston of the master cylinder. An auxiliary-pressure supply system is used for the purpose of pressure delivery during the stop control phase and to safeguard a reserve volume or reserve stroke in the pressure chambers of the master cylinder. To this end, the auxiliary-pressure supply system will be activated and, if need be, check valves will be changed over on attainment of a limit value by virtue of the travel-responsive switch.

Slip-controlled hydraulic brake system

A device for automotive vehicles for both traction control and cruise control is equipped with a common servo motor (13) which, by way of a self-locking gear (14), by way of a switchable friction gear (17) and by way of a linkage (23, 24; 25, 26) acts upon a transmission device interposed into the path of force transmission from an accelerator pedal (1) to the throttle-flap (2) of an internal-combustion engine or to the adjusting lever of the injection pump of a spark-ignition engine. Depending on the switch position of the friction gear (17), the servo motor (13) permits control of either the traction (VR) or the speed (GR). During traction control, a release of the accelerator pedal (1) leads at any time to closing of the throttle-flap (2), while an increase of the pedal force does not have any effect on the position of the throttle-flap. After the activation of cruise control, it is still possible to increase the engine power by further depressing the accelerator pedal (1).

Device for automotive vehicles with traction control and cruise control

A skid-controlled brake system comprising a pedal-operated vacuum booster (3) including a master cylinder (2) connected by way of brake lines (63, 64) to the wheel brakes (31, 32, 33, 34). The system further comprising a hydraulic auxiliary pressure supply system connected, by way of supply lines (24) to the brake circuits and including a hydraulic pump (26). A pressure compensation and pressure fluid reservoir (20) is provided. Wheel sensors (S.sub.1, S.sub.2, S.sub.3, S.sub.4) and electronic switching circuits (44) are provided for detecting the wheel rotating pattern and for generating electric brake pressure control signals to control, for skid control, an electromagnetically operable 3-way/2-position valve inserted into each brake line (63, 64). Control valves (10, 11) are disposed in the piston (6, 7) of the master cylinder (2) opening the pressure fluid passage from the pressure chambers (8, 9) of the master cylinder (2) to the annular chambers (14, 15) formed by circular grooves (54, 55) in the pistons (6, 7) and by the piston bore (65). The control valves (10, 11) are in communication, by way of compensating ports (16, 17) and hydraulic lines (18, 19), with the pressure fluid reservoir (20).

Skid-controlled brake system

A circuit arrangement for controlling the engagement and disengagement of a clutch (8) in the drive connection (2-5) of an automotive vehicle is equipped with transducers (19-22, 51, 52, 53) and with electronic circuits (33) for the logical combination and processing of the signals, and with switching valves (36, 48) which may be fed with the output signals of the circuits (33) and through which the clutch (8) may be operated or locked in the engaged or disengaged position in dependence on driving conditions or rather on measured values characteristic of the driving dynamics and on controlling conditions of the engine.

Circuit arrangement for controlling the engagement and disengagement of

An anti-lock hydraulic brake system with a hydraulic brake power booster (3) and two static brake circuits (I, II) is provided. Connected to one brake circuit (I) are the two rear wheels (HR, HL), while to the other the two front wheels (VR, VL) are connected by way of multi-directional control valve (11 to 16) which sever for the braking pressure modulation and/or the slip control. In the event of slip control, controlled dynamic pressure out of an auxiliary-pressure supply system (4, 5) is introduced by way of the brake power booster (3) into the static brake circuits (I, II) through the intermediary of two hydraulically isolated circuits with main valves (31, 32) which are independent of each other. A positioning device (42) for limiting the pedal travel communicates hydraulically with the main valve (31) of the rear wheel brake circuit (I). The main valve (31) controlling the dynamic fluid flow into the rear wheel brake circuit is equipped with an additional pressure monitoring switch (35). In the event of a failure of the front wheel brake circuit (II), the slip control for the rear wheels (HR, HL) remains in operation.

Anti-lock hydraulic brake system

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 brake system comprising a hydraulic braking pressure generator (1) to which are connected the brake wheels (6-9); an auxiliary pressure supply system including a hydraulic pump (10) and an auxiliary pressure control valve (12) causing an auxiliary-pressure proportional to the pedal force (F). Pressure-controlled multidirectional valves (27,28) are provided establishing a connection between either the braking pressure generator or the auxiliary pressure supply system and the wheel brakes (6-9). The pressure-controlled multidirectional valves (27,28) are structurally combined with a switching mechanism (41,42) to signal the operating condition of the brake system, in particular, a pressure breakdown or defective conditions of the valves. A connection is established, via one of the pressure-controlled multidirectional valves (27), between the pedal travel simulator and the braking pressure generator (1). The brake system can be applied to a slip-controlled system.

Brake system for motor vehicles

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

A master cylinder for a vehicle hydraulic brake system having slip control is disclosed including a master cylinder piston in a bore defining a prechamber connected to an auxiliary fluid energy supply and a working chamber. A tube like projection on the master cylinder piston extends through a one-way sleeve seal into the working chamber. Auxiliary fluid is dynamically supplied from the prechamber past the one way sleeve seal into the working chamber and to the wheel brakes during slip control.

Master cylinder, in particular for a brake slip control apparatus fed

A slip-controlled brake system for motor vehicles with four-wheel drive, wherein one axle (VA) is driven permanently, and the second (HA) is driven by a differential-slip-sensitive coupling (6). The system comprises sensors (S1 to S4) for determining the rotational behavior of the wheels, electronic switching circuits (38, 39, 40) and an auxiliary-pressure supply system (18). For the traction slip control action, brake pressure is introduced into the wheel brakes (11, 12) of only one axle, preferably the permanently driven axle (VA), and the traction slip of all wheels (VL, VR, HL, HR) is, however, controlled thereby. The electronic switching circuits (40) are preferably provided such that the traction slip control action will only set in when, at least at one wheel of the axle (HA) which is not connected to the traction slip control system, an increased traction slip occurs.

Slip-controlled brake system for motor vehicles with four-wheel drive

A vehicular hydraulic brake system with anti-locking, wherein there is provided a master cylinder (27) with a power booster (9) connected upstream thereof for the purpose of supplying the brake-actuating members (32, 33, 36 37) with pressure. Valves (34, 35, 38, 39) are provided for the pressure control of the brake-actuating members (32, 33, 36, 37) and wherein a pressure piston (23) of the hydraulic power booster (9) can be acted upon by the pressure of an auxiliary pressure source (1) in the brake's release direction. To structurally simplify the brake system, the present invention provides that a housing chamber (24) which can be acted upon by the pressure of an unpressurized supply reservoir (5) or of the auxiliary pressure source (1), alternatively, is confined by an end face of the pressure piston (23) remote from the pedal.

Vehicular hydraulic brake system with anti-locking

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.

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Pfungstadt, Germany

Wolfram Seibert