WO2012017037A2

WO2012017037A2 - Brake system for motor vehicles

Info

Publication number: WO2012017037A2
Application number: PCT/EP2011/063446
Authority: WO
Inventors: Marco Besier; Steffen Linkenbach; Stefan A. Drumm; Lothar Schiel; Ronald Bayer; Johann Jungbecker
Original assignee: Continental Teves Ag & Co. Ohg
Priority date: 2010-08-05
Filing date: 2011-08-04
Publication date: 2012-02-09
Also published as: DE102011080312A1; WO2012017037A3

Abstract

The invention relates to a brake system for motor vehicles having a plurality of operating modes, which brake system can be actuated both by the vehicle driver and also independently from the vehicle driver in a preferentially used "brake-by-wire" operating mode, and can be actuated only directly by the vehicle driver in a fall-back operating mode, having a pedal decoupling unit (2) and having an electrohydraulic pressure generating device (5). To permit an uninterrupted pressure build-up by the pressure generating device (5), it is provided according to the invention that the pressure generating device (5) comprises a double-acting piston-cylinder arrangement (30).

Description

Brake system for vehicles

The present invention relates to a brake system for motor vehicles, which is controllable in a "brake-by-wire" mode both by the driver and independently of the driver, preferably operated in the "brake-by-wire" mode and in at least one return ^¬ fall mode can be operated in the only operation by the driver is possible, with a) a brake pedal for actuating a pedal decoupling unit with a housing, two consecutively ^¬ parent pistons, which limit two pressure chambers in the housing, to the operation of the brake system by the driver an actuating force (pedal force) is exercised from ^¬ and are positioned at unoperated brake pedal of return ^¬ spring in a starting position, b) the pressure chambers associated, under atmospheric pressure pressure fluid reservoir, c) a displacement detection device, the actuating travel of the brake pedal or a m it detects the brake pedal connected piston, d) an electronic control unit that the Actuating path processed, e) a pedal feel simulator, which gives the driver the usual Bremsspedalge ^¬ feeling in the "brake-by-wire" mode, f) a pressure modulation unit per wheel brake has an inlet valve and an outlet valve for setting radin ^¬ individual brake pressures consisting of a Bremssys ^¬ temdruck be derived g) with release valves for separating the pressure chambers from the pressure modulation unit, and h) a ^¬ at the pressure modulation unit and the pressure with ^¬ telvorratsbehälter connected electro-hydraulic pressure supply device, which emits a braking system pressure to the pressure modulation unit and ih to compensate rer volume balance from the pressure fluid reservoir pressure medium nachsaugt.

Such a brake system is known from DE 196 26 926 B4 be ^¬ known. As a serious disadvantage of the previously known

Brake system is felt the fact that while the pressure supply device sucks pressure medium, no brake system pressure can be delivered to the pressure modulation unit.

It is therefore an object of the present invention to provide a

Brake system of the type mentioned in order to ver ^¬ mend that continuous delivery of brake system ^¬ pressure by the pressure supply device possible is not interrupted by a Nachsaugprozess possibly becoming necessary during the delivery of pressure.

This object is achieved by the technical features specified in Hauptan ^¬ award. A method for operating the brake system according to the invention is listed in the independent claim 14.

Advantageous developments of the subject invention are specified in the dependent claims.

The present invention is further illustrated in the following descrip ^¬ advertising in connection with accompanying diagrammatic drawings in four embodiments.

Show it:

Fig. 1 is a hydraulic circuit diagram of a first embodiment of an exporting ^¬ approximately Bremsanla ^¬ ge, a second embodiment of the present invention a brake system fiction, modern ^¬ in Fig. 1 corresponding schematic representation,

Fig. 3 shows a third embodiment of a brake system according to Inventive ^¬ in Fig. 1 or Fig. 2 corresponding schematic representation,

Fig. 4 shows a fourth embodiment of a brake system according to Inventive ^¬ in Fig. 1, Fig. 2 or Fig. 3 corresponding schematic illustration.

The brake system illustrated in FIG. 1 consists essentially of Chen assigned from an operable by an actuating or brake pedal 1 hydraulic pedal decoupling unit 2, too ^¬ together acting with the hydraulic pedal decoupling unit 2 pedal feeling simulator 3, one of the hydraulic pedal decoupling unit 2 pressure with ^¬ telvorratsbehälter 4, an electrically controllable pressure supply device 5, an electrically controllable pressure modulator 20, the inlet and outlet valves 6a-6d, 7a-7d comprises and at whose ^{Ausgangsanschlüs ¬} se wheel brakes 8, 9, 10, 11 are connected to a motor vehicle, not shown, and an electronic control unit 12, the processing of sensor signals and the control of the electrically controllable components is used. In the 'brake-by-wire "operating mode ^¬ the input terminals of the intake valves 6a-6d by means of system pressure lines 13a, 13b is supplied with a pressure which is referred to as a system pressure, said pressure sensors 22, 23 for detecting the in the system pressure lines 13a, 13b prevailing pressures are provided. The system pressure lines 13a, 13b form components of a first and a two ^¬ th brake circuit, which are designated by the reference I or II, wherein, for example, to the first brake ^¬ circle I, the front axle associated wheel brakes 8, 9 and the second brake circuit II the wheel brakes 10, 11 associated with a rear axle of the motor vehicle are connected. Return lines 14a, 14b, which are connected to the output ^¬ connections of the exhaust valves 7a-7d, connect the exhaust valves 7a-7d with the non-pressurized

Pressure medium reservoir 4 (open system).

Continues to be seen from Fig. 1, the hydraulic pedal decoupling unit 2, which can be regarded as a ^¬ Actuate the supply unit of the brake system according to the invention, in a (brake master) housing 21, two hydraulic pistons 15, 16 arranged one behind the other delimiting the hydraulic pressure chambers 17, 18 which, together with the pistons 15, 16, form a dual-circuit master cylinder or a tandem master cylinder. The pressure chambers 17, 18 are on the one hand via trained in the piston 15, 16 radial bores with the pressure medium ^¬ reservoir 4 in connection, these holes are shut off by a relative movement of the piston 17, 18 in the housing 21, and on the other hand with the above-mentioned system pressure lines 13a, 13b are connected to the input ports of the aforementioned pressure modulation or intake valves 6a-6d. In the hydraulic system pressure lines 13 a, 13 b are each a separating valve 24 a, 24 b is inserted ^¬ , which are designed as electrically actuated, preferably normally open (SO-) 2/2-way valves. A pressure sensor 25 connected to the pressure chamber 18 detects the pressure built up in the pressure chamber 18 by displacing the second piston 16. In addition, the pressure chambers 17, 18 take unspecified return springs, which bias the pistons 15, 16 against the actuation direction. A coupled to the brake pedal 1 piston rod 26 acts together with the first (master cylinder) piston 15, wherein the actuation path of the brake pedal 1 and the coupled to the Bremspe ^¬ dal piston 15 is detected by a preferably redundantly designed displacement sensor 19.

In addition, it can be seen from the diagrammatic illustration of the brake system according to the invention that the previously mentioned pedal feel simulator device 3 is designed hydraulically and essentially consists of a simulator chamber 27, a simulator spring chamber 28 with simulator spring 69 and a simulator piston 29 separating the two chambers 27, 28. The simulator chamber 27 is connected to the first pressure chamber 17 of the tandem master cylinder 2, while the Simulatorfederkammer 28 under Intermediate circuit of an electrically operable simulator release valve 41 is connected to the above-mentioned pressure ^¬ medium reservoir 4. A the

Simulator release valve 41 parallel return valve ^¬ 44 is connected to the Simulatorfederkammer 28 and allows independent of the switching state of the Simulatorfreigabeventils 41 and regardless of a Dros ^¬ selwirkung the hydraulic simulator Abströmverbindungen a largely unthrottled inflow of the pressure medium in the Simulatorfederkammer 28th

Further, 1 is shown in FIG. Recognized that the electrohydraulic raulische pressure supply device 5 is designed as a hydraulic, double-acting cylinder-piston assembly 30, the piston 33 by means of a Kraftübert ragungsstange ^¬ 35 by a schematically indicated electric motor 40 with the interposition of a non- represented rotational translation gear is operable. The electric motor 40 and the rotational-translation gear form a linear actuator, wherein a rotor position sensor serving to detect the rotor position of the electric motor 40, only schematically drawn ^¬ is provided with the reference numeral 39. Other sensors, such as a temperature sensor 49, provide the electronic control unit 12 with state information about the electric motor 40 or the linear actuator. The linear actuator facing the annular surface of the piston 33 defines a first pressure chamber 31, while its pointing in the drawing to the left end face defines a second hydraulic pressure chamber 32. The hydraulically effective cross-sectional area of the first pressure chamber 31 is reduced by the cross-sectional area of the rod 35 which serves to transmit power between the linear actuator 40 and the piston-cylinder arrangement 30 and which dips into the first pressure chamber 31. The first printing Cavities 31 is sealed by a first sealing member 37 thereby to a schematically indicated, leading to the pressure fluid reservoir 4 hydraulic connection 36, which is adapted to seal against a pressure gradient from the ers ^¬ th pressure chamber 31 to the hydraulic connection 36th A second sealing element 38 seals the hydraulic connection 36 with respect to the linear actuator 40. A third sealing element 34 arranged on the piston 33 seals the first pressure chamber 31 with respect to the second pressure chamber 32.

In addition, the two pressure chambers 31, 32 over to

Pressure fluid supply reservoir 4-closing non-return valves 45, 46 with the latter compound, wherein in addition between the first pressure chamber 31 and the pressure fluid supply reservoir 4, an electrically operable, preferably normally offe ^¬ nes is arranged (NO) 2/2-way valve 47th Finally, FIG. 1 reveals that the two pressure chambers 31, 32 are connected to the brake circuits I, II or input ports of the inlet valves 6a by opening electrically actuatable connecting valves 42a, 42b which are inserted in the aforementioned system pressure lines 13a, 13b. 6d are connectable. In this case, each of the additional valves 42a, 42b is connected to the pressure chambers 31, 32 closing check valve 43a, 43b in parallel. The two brake circuits I, II and the system pressure lines are connected via a further hydraulic connection 50, which can be opened or shut off by means of an electrically actuated, preferably normally closed (SG) 2/2-way valve 68. In addition, it should be mentioned that all circular symbols, which are associated with, for example, the line sections 14a, b, the check valves 45, 46, etc., represent the pressure fluid supply reservoir 4 leading hydraulic lines. In the embodiment shown in Fig. 2 second advantageous embodiment of the braking system according to the invention are the wheel brakes 8-11 ^¬ associated pressure modulation intake valves 60a-60d as an electrically operable, normally closed

(SG) 2/2-way switching valves, while the off ^¬ lassventile 70a-70d as analog controllable, normally open

(SO) 2/2-way valves are formed in the

energized switching position to fulfill the function of the wheel brakes 8-11 out opening check valves. The output terminals of the exhaust valves 70a-70d are brake circuit connected to line leading to the pressure medium reservoir 4 line sections 140a, b, in which elekt ^¬ risch operable, normally closed 2/2-way valves 62, 63 are inserted. Before the input terminals of the 2/2-way valves Druckkam ^¬ mers 17, 18 of the master cylinder 2 are connected via the isolation valves 24a, b. The pressure chambers 31, 32 of the electrohydraulic pressure supply device 5 are connected via respective associated, to the pressure chambers 31, 32 towards closing check valves 51, 52 with a line section 53 to which the pressure modulation inlet valves 60a-60d are directly connected.

In the embodiment shown in Fig. 3 advantageous development of the subject invention, the pressure chambers 31, 32 of the electro-hydraulic pressure supply device 5 are assigned on each of the pressure chambers 31, 32 towards closing ^¬ sequent check valves 64, 65 connected to a line section 54 to which on further, to the pressure chambers 31, 32 towards closing check valves 55, 56, the brake circuits I, II are connected. Between the output terminals of the exhaust valves 7a-7d and the pressure fluid reservoir 4, an analog controllable, normally closed ^¬ nes (SG) 2/2-way valve 66, 67 are connected in each case. In the embodiment of the brake system according to the invention shown in FIG. 4, the embodiment of the pressure modulation valves 6a-6d, 7a-7d assigned to the wheel brake 8-11 corresponds to the circuit shown in FIG. 1 and FIG. However, the connection of the pressure spaces 31, 32 of the electro-hydraulic pressure supply device 5 and 30 to the brake circuits I, II is preferably made such that the first pressure chamber 31 via a respective non-return valve 57, 58 which are connected in anti-parallel (with the ers ^¬ th I) or the second brake circuit II is connected. Here, the center of the antiparallel arrangement of the check valves 57, 58 and the first pressure chamber 31 via an electrically actuated, normally open 2/2-way valve 59 to the pressure medium reservoir 4 is connectable. The connection of the second pressure chamber 32 to the two brake circuits I, II via connecting valves 42c, 42d, which in each case one to the brake circuit I or II opening check valve 61a, 61b is connected in parallel. The rest of the hydrauli ^¬ rule circuit corresponds to the embodiment shown in FIG. 1.

Finally, it should be mentioned that the brake system shown in the drawings can be modular. In the example of FIG. 1, a first module 100 would essentially be the master brake cylinder arrangement 2, the pedal travel sensor 19, the hydraulic pedal feel simulation device 3, the pressure medium reservoir 4, sections of the hydraulic lines 13a, 13b, and optionally an electrically actuated, normally open 2/2-way valve 48 to ^¬ summarize, which is connected between the first pressure chamber 17 and the pressure medium reservoir 4. A second module 200 is formed by the electro-hydraulic actuator 5, while a third module 300 is formed by the electrostatic ^¬ African control and regulating unit, which in the pre- her forthcoming text is denoted by the reference numeral 12. Finally, all electrically actuable valves 6a-6d, 7a-7d, 24a, 24b, 41, 42a, 42b, 47, 48, the return ^¬ check valves 43a, 43b, 44 and all pressure sensors 22, 23, 25 to a fourth module 400th taken together, all modules 100 to 400 are constructed as independently assembled and testable units.

The operation of the brake system according to the invention both in the preferred mode "brake-by-wire" and in the so-called. Fallback mode results for the working in the relevant technical field expert from the disclosure of the present patent application and therefore need not be explained in detail.

Claims

Claims:

1. brake system for motor vehicles, which is controlled in a "brake-by-wire" mode both by the driver and independently of the driver, preferably in the "brake-by-wire" mode is operated and operated in at least one Rückfallbetriebs ^¬ art can be in which only the operation by the driver is possible, with

a) a brake pedal (1) for actuating a pedal decoupling unit (2) with a housing (21), two successively arranged pistons (15, 16) in the housing (21) two pressure chambers (17, 18) limit, on the at Actuation of the brake system by the driver an actuation ^¬ force (pedal force) is exercised and positioned at reset brake springs (1) of return springs in a starting position b) a pressure chambers (17, 18) associated with atmospheric pressure fluid reservoir (4),

c) a position detection device (19) which detects the actuation path of the brake pedal (1) or a piston (15) connected to the brake pedal, d) an electronic control unit

(12), which processes the actuation path,

e) a pedal feel simulator (3) in the "brake-by-wire" mode gives the driver the usual brake pedal feel,

f) a pressure modulation unit (20) which has per wheel ^¬ brake (8, 9, 10, 11) an inlet valve (6a-6d, 60a-60d) and an outlet valve (7a-7d, 70a-70d) for setting wheel-individual brake pressures derived from the brake system pressure become,

g) with separating valves (24a, 24b) for separating the

Pressure chambers (17, 18) of the pressure modulation unit (20), as well

h) a to the pressure modulation unit (20) and the pressure fluid reservoir (4) connected electrohydraulisehen pressure supply device (5), which emits the brake system pressure to the pressure modulation unit (20) and sucks to balance their volume balance from the Druckmittelvorratsbe ^¬ container (4) pressure medium,

characterized in that

the pressure supply device (5) comprises a double-acting piston-cylinder arrangement (30).

Brake system according to claim 1, characterized in that a piston (33) of the piston-cylinder arrangement (30) separates two pressure chambers (31, 32) from each other, where ^¬ at a pressure build-up in the first pressure chamber (31) during a backward movement of the piston ( 33) and in the second pressure chamber (32) during a forward movement of the piston

(33).

Brake system according to claim 2, characterized in that the piston (33) with at least one sealing element

(34) is provided, which separates the two pressure chambers (31, 32) from each other and is adapted to a pressure gradient from the first (31) to the second pressure chamber

(32) and from the second (32) to the first pressure chamber (31) to seal.

Brake system according to one of claims 1 to 3, characterized in that the electrohydraulic pressure provision device (5) by the piston-cylinder arrangement (30) and a piston-cylinder arrangement (30) actuated linear actuator (40) is formed, wherein the power transmission between linear actuator (40) and piston-cylinder arrangement (40) by means of a rod (35), which dips into the first pressure chamber (32).

5. Brake system according to one of claims 2 to 4, characterized in that the first pressure chamber (31) by means of a hydraulic connection (36) with the pressure medium reservoir (4) is connectable, wherein the first pressure chamber (32) relative to the hydraulic connection

(36) is sealed by a second sealing element (37), which is adapted to a pressure gradient from the first pressure chamber (31) to the hydraulic connection

(36) seal.

6. Brake system according to claim 5, characterized in that a third sealing element (38) is provided, which separates the hydraulic connection (36) from the linear actuator (40).

7. Brake system according to one of claims 2 to 6, characterized in that the two pressure chambers (31, 32) each have a non-return valve (45, 46) is associated, which allows a suction of the pressure medium from the Druckmit ^¬ telvorratsbehälter (4).

8. Brake system according to one of claims 2 to 7, characterized in that the first pressure chamber (31) via a first Zuschaltventil (42 a) with a first brake ^{circuit ¬} (I) and the second pressure chamber (32) via a two tes Zuschaltventil (42 b) with a second brake circuit (II) is connectable.

9. Brake system according to claim 8, characterized in that a lockable connection (50, 68) between the brake circuits (I, II) is provided.

10. Brake system according to one of claims 2 to 9, characterized in that both the first pressure chamber (31) and the second pressure chamber (32) via a respective associated non-return valve (52, 53) with a Lei ^¬ processing section (13 a, 13 b) is connected to the ^¬ all, the wheel brakes (8, 9, 10, 11) associated intake valves (6a-6d) are connected.

11. Brake system according to one of claims 2 to 10, characterized in that both the first pressure chamber (31) and the second pressure chamber (32) via a respective associated check valve (64, 65) with a Lei ^¬ processing section (54) is connected , to each of which a check valve (55, 56), the two brake circuits (I, II) are connected.

12. Brake system according to one of claims 2 to 11, characterized in that the second pressure chamber (32) via a first Zuschaltventil (42c) with the first brake ^¬ circle (I) and via a second Zuschaltventil (42d) with the second brake circuit ( the first pressure chamber (31) via a combination of anti-parallel connected non-return valves (57, 58) of both brake circuits (I, II) connectable II), currency ^¬ rend is connected.

13. Brake system according to one of claims 1 to 12, characterized in that the travel simulator (3) is hydraulically actuable and has a simulator piston (29), a simulator chamber (27) and one of the

Simulator chamber (27) by the simulator piston (29) separated, a simulator spring (69) receiving

Simulator spring chamber (28), wherein the

Simulator (27) with one of the pressure chambers (17, 18) is in hydraulic communication and the action of the path simulator (3) in the "brake-by-wire" mode by means of a simulator release valve (41) can be switched, which is a compound of

Simulator spring chamber (28) with the pressure fluid reservoir (4) allows.

14. A method for operating the brake system according to at least one of claims 2 to 13, characterized in that at a brake system pressure build-up of a Vor ^¬ downward stroke of the piston (33) of the piston-cylinder assembly (30) and the linear actuator (40), is switched to a reverse stroke as soon as the Druckmit ^¬ tel volume of the second hydraulic pressure chamber (32) is almost completely displaced and that at a brake system pressure build-up of a backward stroke of Kol ^¬ bens (33) of the piston-cylinder assembly (30) and the linear actuator (40), in a forward stroke ^{umgeschal ¬} tet as soon as the pressure ^fluid volume of the first hydraulic pressure chamber (31) is almost completely ver ^¬ urges.

15. A method for operating the brake system according to claim 14, characterized in that the need for a particularly ^¬ high braking system pressure of the backward stroke of the piston (33) of the piston-cylinder assembly (30) and the linear actuator (40) is used to at amount moderately the same Aktuatorkraft by the effective compared to the forward stroke lower surface of the Kol ^¬ ben (33) to generate a higher pressure.