KR20160106600A - Brake system for motor vehicles - Google Patents

Abstract

The present invention relates to a brake system for motor vehicles having a plurality of operating modes, wherein the brake system is operated by the vehicle operator in a "brake-by-wire & And may be directly controlled only by the vehicle operator in the fallback operation mode. According to the present invention, in order to reduce the number of continuously electrically powered valves required for brake pressure control in normal operation, during the reduction of pressure in the "brake-by-wire & 18a and 18b to maintain the pressure at the pressure equalizing connection 49 at the level of the pressure providing device 5 and to allow the pressure reducing volume flow from the pressure equalizing connection 49 to the pressure providing device 5 to be conductable (38, 50, 51) are provided.

Description

BRAKE SYSTEM FOR MOTOR VEHICLES < RTI ID = 0.0 >

The present invention relates to a brake system for motor vehicles according to the preamble of claim 1.

A brake system for one such motor vehicle is known, for example, from DE 10 2011 081 463 A1. Previously known brake systems include a master brake cylinder operated by a brake pedal having two pressure chambers, wheel brakes, an electrically controllable pressure supply device, a pressure modulation valve device with two valves per wheel brake, As well as two additional isolation valves per brake circuit required to decouple the master brake cylinder pressure chambers from the wheel brakes in the " by-wire "operating mode, as well as to the pressure chambers of the master brake cylinder and to the simulator enabling valve And a brake pedal travel simulator that can be switched on and off by the brake pedal. In order to realize the high availability of the brake system even in the fallback mode, the brake system includes a total of 30 valves, and the simulator enabling valve must be implemented as a normally closed state, whereby the electrical power supply of the brake system in the fallback mode In case of a failure of the device, the realization of the increase of the hydraulic pressure in the wheel brakes by the vehicle operator and the switch-off of the brake pedal running simulator are ensured. In the previously known brake system, a large number of valves become a disadvantage, leading to high manufacturing costs for the brake system. Also, a disadvantage is the large number of valves that must be activated for normal on-braking in the "brake-by-wire"

It is therefore an object of the present invention to provide a brake system that can be implemented with reduced valve complexity and at the same time can be manufactured at low cost.

This object is achieved according to the invention by the brake system according to claim 1.

The present invention allows the pressure in the pressure balanced connector of the second pressure chamber to be maintained at the level of the pressure supply device during the reduction of pressure in the " brake-by-wire "mode of operation, Based on the idea that means is provided to pass to the device.

The means is preferably in the form of a normally open 2 < 2 > / 2-way control valve, which is electrically operated, at the hydraulic connection between the pressure balanced connector and the pressure supply device, as well as the connection between the pressure balanced connector and the pressure medium storage container .

According to a preferred embodiment of the present invention, a check valve that opens toward the pressure supply device is inserted into the connection between the pressure equalizing connector and the pressure supply device.

The present invention provides the advantage that an additional separation valve per brake circuit between the master brake cylinder and the discharge valve can be omitted.

Preferably, the second pressure chamber of the master brake cylinder is formed by two sub-pressure chambers arranged in parallel, each of which is bounded by a second piston and hydraulically connected reversibly to each other. Particularly preferably, the first piston can bring a power transmission connection to the second piston, for example a mechanical connection.

According to the space saving embodiment of the present invention, one of the sub-pressure chambers is coaxially connected downstream with respect to the first piston and the first pressure chamber. In this case, the other sub-pressure chambers having the associated second pistons are disposed at a distance from the first pressure chamber. Particularly preferably, the associated second piston is capable of receiving a controlled pressure in the first pressure chamber through the hydraulic connection line.

Preferably, the restoring spring biasing the first piston is disposed outside the first pressure chamber coaxially with respect to the first piston.

According to the development of the invention, the restoring spring is arranged in the hydraulic annular chamber having a connection to the first pressure chamber which is coaxial with respect to the first piston and can be shut off by the first piston. Particularly preferably, the hydraulic connection is provided between the annular chamber and the pressure medium storage container, wherein a parallel circuit of an electrically operated normal time open simulator with a check valve opening towards the annular chamber is connected.

Preferably, the brake pedal travel simulator is integrated into the first piston.

Preferably, both electrically operated suction valves and also electrically operated discharge valves are in the form of normally open 2 < 2 > / 2-way control valves. This results in a particularly small number of valves powered for normal open braking in the " brake-by-wire "operating mode.

Alternatively, the electrically operated intake valves are preferably in the form of normally closed 2 < 2 > directional control valves by electrical boosting of the closing force.

A check valve, which is closed toward the pressure supply device, is preferably disposed in each of the hydraulic connections between the pressure supply device and the suction valves.

The hydraulic connection is preferably provided between the first pressure chamber of the master brake cylinder and the chamber of the pressure medium storage container, wherein a normally closed discharge valve is operated which is electrically operated.

It is also preferred that a hydraulic connection with an electrically operated valve is provided, by means of which the pressure supply device is reversibly connected to the first pressure chamber. The valve is particularly preferably implemented as a normally closed condition. The hydraulic connections are:

제 1 압력 챔버와 압력 매체 저장 컨테이너 사이의 유압식 접속부와 압력 공급 디바이스 사이에, 또는

Between the hydraulic connection between the first pressure chamber and the pressure medium storage container and the pressure supply device, or

제 1 압력 챔버에 가역적으로 접속된 환형 챔버와 압력 매체 저장 컨테이너 사이의 유압식 접속부와 압력 공급 디바이스 사이에 특히 바람직하게 배치된다.

And is particularly preferably disposed between the pressure supply device and the hydraulic connection between the annular chamber and the pressure medium storage container reversibly connected to the first pressure chamber.

The electrically controllable pressure supply device is preferably in the form of a single circuit electrohydraulic actuator.

Preferably, the actuator of the pressure supply device is formed by an electric motor as well as a cylinder-piston device operatively connected behind the electric motor, wherein the piston is driven by an electric motor, One sensor is provided.

Further preferred embodiments of the invention will be apparent from the following detailed description, taken in conjunction with the dependent claims and the drawings.

In the drawing:
1 is a hydraulic circuit diagram of a first embodiment of a brake system according to the present invention.
2 is a hydraulic circuit diagram of a second embodiment of the brake system according to the present invention.

The brake system shown in Fig. 1 includes a hydraulic operation unit 1 operated by an operation or brake pedal not shown, a pressure medium storage container (not shown) associated with the hydraulic operation unit 1 together with an electric level warning device 3 2, a brake pedal running simulator 4, an electrically controllable pressure supply device 5 and an electrically controllable pressure changing or suction and discharge valves 6a-6d, 7a- 7d which are connected to the wheel brakes 8, 9, 10, 11 of the motor vehicle which are not shown. In this case, the check valves 57b and 57d, which are closed toward the master brake cylinder 1, are connected to the discharge valves 7b and 7d of the wheel brakes 9 and 11, which are associated with the front axle of the vehicle, 7d are in parallel and the discharge valves 7a-7d are in the form of normally open (NO) analog operated 2/2-way control valves. In the illustrated exemplary embodiment, the input ports of the input valves 6a-6d, shown as normally open (NO) analog actuated 2/2-way control valves, are connected by system pressure lines, (12a, 12b). The components 6a-6d, 7a-7d, 12a, 12b, 57b, 57d described above can be combined to form an electrohydraulic module and thus form a pressure modulation unit not shown in detail.

As also shown in the figures, the hydraulic operating unit 1 of the exemplary brake system is formed in the electro-hydraulic control and regulation unit 31, and is connected to the dual circuit master brake cylinder (not shown) along with the pistons 15, 16a, And hydraulic pistons 15, 16a, 16b that bound hydraulic chambers or pressure chambers 17, 18a, 18b forming the hydraulic chambers 17, 18a, 18b. In this case, the first piston 15 is also referred to as the primary piston and the pressure chamber 17 associated with the piston is referred to as the primary pressure chamber while the secondary (sub) pressure chambers 18a, 18b And the second pistons 16a and 16b for binding one primary pressure chamber 17 are referred to as secondary pistons. (Secondary) sub-pressure chambers 18a, 18b are disposed adjacent to each other (e.g., in parallel) with associated secondary pistons 16a, 16b in the illustrated embodiments. (Secondary) sub pressure chambers 18a, 18b receive restoration springs 19a, 19b that position secondary pistons 16a, 16b in the initial position when the master brake cylinder is not actuated. A restoring spring 25 provided for the same purpose and biasing the primary piston 15 is connected to the primary pressure chamber 17 in the hydraulic annular chamber 24 connected to the primary pressure chamber 17 when the master brake cylinder 1 is not operated, And is disposed coaxially with respect to the head piston (15). The restoring spring 25 supported on a stop not shown in detail in the electrohydraulic control and regulation unit 31 may also be arranged in the primary pressure chamber 17 as well. The hydraulic annular chamber 24 is connected to the pressure medium storage container 2 by a pressure medium line 46 into which a normally open NO 2 2 directional control valve or simulator valve 47 is inserted.

The pressure chambers 17 and 18a and 18b are connected to the pressure medium storage container 2 by means of pressure medium lines 46 and 33 where they are connected to the electrohydraulic control and regulation unit 31 Can be blocked by the relative displacement of the pistons 15 and 16a, 16b.

(Secondary) sub-pressure chambers 18a and 18b are hydraulically connected to each other, wherein the connection can be blocked by the relative displacement of the pistons 16a and 16b.

The first piston 15 and the second piston 16a, 16b are arranged such that the first piston 15 can bring about a power transmission (mechanical) connection to the second pistons 16a, 16b.

The first pressure chamber 17 is also reversibly connected to the pressure medium storage container 2 by a pressure medium line 58 together with the discharge valve 20 which is normally closed at the time of normal operation. Therefore, the pressure chamber 17 can also be connected to the pressure medium storage container 2 by opening the discharge valves 20, thereby allowing the pressure chamber 17 to be "released" Can be connected.

On the other hand, the secondary sub pressure chambers 18a and 18b are connected to the discharge valves 7a and 7b or 7c and 7d by hydraulic lines 22a (brake circuit I), 22b (brake circuit II) And is connected to the brakes 8-11.

A pressure sensor 56 connected to the annular chamber 24 detects an increase in pressure in the annular chamber 24 due to displacement of the first piston 15. The piston rod 23 couples the unshown pivoting movement of the brake pedal to bring about the operation of the pedal relative to the translational displacement of the first (primary) piston 15, And is detected by a displacement sensor 30 which is implemented redundantly. As a result, the corresponding piston travel signal is a measure of the brake pedal operating angle. This indicates the brake driver's brake request.

The electronic control and regulation unit 39 is used for the operation of all of the above electrically operated components.

In addition, the brake pedal running simulator 4 described above is operated hydraulically and essentially comprises a simulator chamber 26 connected to the hydraulic annular chamber 24, a simulator spring chamber 27 for receiving the elastomeric simulator spring 29, It is also evident from the graphical representation of the exemplary brake system that it is essentially constituted by a simulator piston 28 separating the two chambers 26, 27 from each other. A sealing ring 55, shown only schematically, is used to seal the simulator piston 28.

In this case, the simulator action may be turned on by activating the simulator valve 47. The backflow prevention valve 21 disposed in parallel with the simulator valves 47 and 25 is configured to substantially prevent the pressure medium from the pressure medium storage container 2 to the annular chamber 24 substantially independently of the switching state of the simulator valve 47 Resulting in an unimpeded return flow.

1, the above-described electrohydraulic pressure supply device 5 is essentially constituted by an electromechanical drive unit 35 as well as a hydraulic cylinder piston device 34, for example, The mechanical drive unit is formed by an electric motor having a mechanical gearbox connected downstream to convert the rotational motion of the electric motor to the translational displacement of the hydraulic piston 36 so that hydraulic pressure is transmitted to the hydraulic cylinder piston device 34 In the pressure chamber 37 of FIG. The electromechanical drive unit 35 is energized by an electric energy storage device not shown. In order to enable the appropriate adjustment of the current delivered to the electric motor 35, sensors for detecting characteristic operating parameters of the electric motor 35, in particular current sensors 40 for its phase currents, are provided . In a further example, a rotor piston sensor, which is used to detect a rotor piston of an electric motor and is shown only schematically, is referred to as 41. In addition, a temperature sensor 42 may also be used to detect the temperature of the motor windings. The piston travel is preferably detected indirectly by using the rotation angle of the electric motor 35 in this case. This is particularly advantageous when an electronically rectified electric motor is used with conventional proprietary rotor position sensing. The pressure sensor provided at 45 is used for detecting the system pressure or the hydraulic pressure produced by the electrohydraulic pressure supply device 5. [

The system pressure line 54 is connected to the pressure chamber 37 of the hydraulic piston cylinder device 34 and the pressure chamber 37 is connected by the respective line segments 54a and 54b to the system pressure line segments 12a, 12b. The check valves 51a and 51b opened toward the wheel brakes 8 and 9 or 10 and 11 are inserted into the respective line segments 54a and 54b, respectively. The reverse suction of the pressure medium from the pressure medium storage container 2 to the pressure chamber 37 is caused by the pressure medium delivery line 44, which has a flow cross section which is largely selected to minimize the adsorption resistances. A check valve 43 that is closed toward the pressure medium storage container 2 and inserted into the pressure medium delivery line 44 enables the mentioned reverse aspiration of the pressure medium into the pressure chamber 37.

The pressure in the pressure balanced connector 49 of the second pressure chambers 18a and 18b (at the pressure balance line 33) is lower than the pressure at the pressure supply device 5 (during the pressure decrease in the "break- And the line segment 50 is connected to the pressure of the electrohydraulic pressure supply device 5 so that an increase of the pressure volume flow from the pressure balance connector 49 is passed to the pressure supply device 5. [ The pressure balance connector 49 in which the chamber 37 or the pressure medium transfer line 44 described above and the check valve 51c opened toward the pressure chamber 37 of the electrohydraulic pressure supply device 5 are inserted, (Or pressure medium line 33). Normally open, bi-directional control valve 38, preferably analogically regulated, is disposed in the pressure medium line 33 between the pressure balanced connector 49 and the pressure medium storage container 2 for the same purpose.

A normally closed (NC) 2/2-way switching valve 52 is inserted in the line segment 53 between the pressure medium delivery line 44 and the pressure medium line 58 described above.

For normal braking in the " brake-by-wire "mode of operation, only valves 38, 20 and 47 are activated, i.e., powered. Thus, the exemplary embodiment provides the advantage that the number of valves powered for normal braking in the "brake-by-wire" mode of operation is reduced.

Figure 2 shows a hydraulic circuit diagram of a second embodiment of a brake system, in particular according to the invention, which is space-saving. The same reference numerals are used in the components of the second exemplary embodiment, corresponding to those in FIG. In the second exemplary embodiment, the above-described brake pedal running simulator 4 is disposed in the primary piston 150, particularly in its central region.

The normally closed (NC) 2/2-way switching valve 52 is inserted into the line segment 53 between the pressure medium transfer line 44 and the above-described pressure medium line 46 in accordance with the example. This is an alternative arrangement of a line segment 53 having a switching valve 52 which may also be implemented in a corresponding braking system, in contrast to the exemplary embodiment of Fig. Thus, in the corresponding braking system, which is different from the second exemplary embodiment, the line segment 53 with the switching valve 52 also includes a pressure medium line 58 and a pressure medium delivery line 44 (as in Figure 1) As shown in FIG.

The first secondary sub pressure chamber 180a bounded by the first secondary piston 160a in the second exemplary embodiment is preferably parallel to the second secondary sub pressure chamber 180b (For example, separated from the primary pressure chamber 170, the secondary piston 160b and the secondary sub-pressure chamber 180b) to the hydraulic control and regulating unit 31 so that the first secondary piston 160a Is subjected to a controlled pressure in the first (primary) pressure chamber 170, the second exemplary embodiment is different from the first exemplary embodiment. Primary pressure chamber 170 is bounded by primary piston 150 and second secondary piston 160b (as well as control and regulation unit 31). The primary pressure chamber 170 is also connected to the hydraulic pressure chamber bounded by the first secondary piston 160a and the control and adjustment unit 31, not shown in detail, by a hydraulic connection line not shown in detail.

The second secondary sub pressure chamber 180b is coaxially and downstream connected to the primary piston 150 such that upon failure of pressure controlled in the primary pressure chamber 170, It is possible to transmit the mechanical power to the main body 160b. The mechanical power transmission from the primary piston 150 to the first secondary piston 160a is not possible due to the discrete arrangement.

The intake valves 106a-106d are in the form of normally closed (NC) analog-tuned 2/2-way control valves in the case of the second exemplary embodiment. These valves may also be used in the first exemplary embodiment as well.

During normal braking in the " brake-by-wire "mode of operation, valves 38,20, 47 and 106a-106d are actuated, i.

Separately, numerous modifications of the invention may be suggested without departing from the scope of the invention. As an example, the feasibility of implementing wheel modulation valves so that these valves are operated in multiplex mode is also anticipated. In this case, only one normally-normally open (NO) analog-tuned 2/2-way control valve is associated with each wheel brake 8-11. A simple (non-pulse) pump or a reversible pump may be used as the pressure supply device 5. In addition, effective wheel individual multiplexing by omitting the check valves 57b, 57d at the discharge valves 7b, 7d can also be selectively implemented for reducing the pressure by the pressure supply device.

The operation of the braking system according to the present invention can be achieved by the teachings of the present patent application, in both the preferred "break-by-wire" mode of operation and also in the so called fallback mode, by those skilled in the art I do not explain it in detail because it is clear to you.

Claims (14)

Both by the driver of the vehicle and also independently of the driver of the vehicle, can be operated in the " brake-by-wire "mode of operation and operate normally in the" A brake system for motor vehicles capable of being operated in at least one fallback mode capable of only operation by the driver of the vehicle,
The brake system includes:

The hydraulic wheel brakes 8, 9, 10, 11,

A brake pedal for actuating a master brake cylinder (1), wherein the wheel brakes (8, 9, 10, 11) can receive the pressure of the brake pedal in the fallback mode, At least one first piston (18a, 18b, 180a, 180b) that is bound to the first pressure chambers (17, 170) as well as the second pressure chambers (15; 150) and a second piston (16a, 16b; 160a, 160b)

A pressure medium storage container 2 that can be connected to the second pressure chamber at atmospheric pressure by a pressure balance connector 49,

A progress detection device (30) for detecting the progress of the operation of the first piston (15)

Brake pedal feel "to the driver of the vehicle in the" brake-by-wire "mode of operation and to the master brake cylinder 1, to the simulator piston 28, Connected to a simulator chamber 26 which receives the volume of displaced pressure from the master brake cylinder in the " wire "operating mode, as well as to a simulator spring chamber 27 which receives the simulator spring 29, (4),

An electrically controllable pressure supply device (5) for actuating the wheel brakes (8, 9, 10, 11)

Electrically operated suction valves 6a-6d, 106a-106d for each wheel brake, and electrically operated discharge valves 7a-7d, in particular for setting the wheel individual brake pressures, and

In particular the pressure supply device 5, as well as the electronic control and regulation unit 39 for operating the suction valves and in particular the discharge valves,
The pressure in the pressure equalizing connector 49 of the second pressure chambers 18a, 18b, 180a and 180b is reduced to the level of the pressure supply device 5 during the reduction of the pressure in the "brake-by- Characterized in that means (38, 50, 51) are provided for causing a pressure reduction volumetric flow to be maintained at the pressure equalization connector (49) and to be passed from the pressure equalization connector (49) to the pressure supply device Brake system for motor vehicles. The method according to claim 1,
The means is provided at the connection 33 between the pressure equalizing connector 49 and the pressure medium storage container 2 as well as at the hydraulic connection 50 between the pressure equalizing connector 49 and the pressure supply device 5 , The valve is in the form of a normally open 2 < 2 > / 2-way control valve (38) operated electrically. 3. The method of claim 2,
And a check valve (51) opened toward the pressure supply device is inserted into the connection part (50) between the pressure balanced connector and the pressure supply device. 4. The method according to any one of claims 1 to 3,
The second pressure chamber of the master brake cylinder is formed of two sub-pressure chambers (18a, 18b; 180a, 180b) arranged in parallel,
Each of the sub-pressure chambers is bounded by a second piston (16a, 16b; 160a, 160b) which can bring about a power transmission connection to the first piston (15, 150) and reversibly hydraulically connected to each other Characterized in that the brake system for motor vehicles. 5. The method of claim 4,
One of the sub pressure chambers 180b is coaxially connected downstream to the first piston 150 and the first pressure chamber 170 and the other sub pressure chamber 180a is connected to the associated second piston 160a, The first pressure chamber 170 and the second pressure chamber 170,
Characterized in that said associated second piston (160a) is capable of receiving a controlled pressure in said first pressure chamber (170), in particular by means of a hydraulic connection line. 6. The method according to any one of claims 1 to 5,
Wherein the restoring spring (25) for biasing the first piston (15, 150) is disposed outside the first pressure chamber (17, 170) and coaxially with the first piston Brake system for. The method according to claim 6,
The restoring spring (25) for biasing the first piston (15, 150) includes a first pressure chamber (17, 170) coaxially formed on the first piston and capable of being blocked by the first piston Is disposed in a hydraulic annular chamber (25) including a connection portion to a fluid passage
In particular, a hydraulic connection 46 is provided between the annular chamber 24 and the pressure medium storage container 2,
Characterized in that an electrically operated, normally open, simulator valve (47) is connected in parallel with a check valve (21) opened towards the annular chamber (24). 8. The method according to any one of claims 1 to 7,
Wherein the brake pedal travel simulator (4) is integrated within the first piston (150). 9. The method according to any one of claims 1 to 8,
Characterized in that both said electrically actuated intake valves (6a-6d) and also electrically operated discharge valves (7a-7d) are in the form of normally open two-way control valves Brake system for. 9. The method according to any one of claims 1 to 8,
Characterized in that the electrically operated discharge valves (106a-106d) are in the form of normally closed two-way control valves by electrical boosting of the closing force. 11. The method according to any one of claims 1 to 10,
Individual backflow prevention valves 51a and 51b that are closed toward the pressure supply device 5 are provided between the pressure supply device 5 and the hydraulic valves 54a and 54b between the suction valves 6a to 6d and 106a to 106d, , 54b, respectively. ≪ / RTI > 12. The method according to any one of claims 1 to 11,
A hydraulic connection 58 is provided between the first pressure chamber 17, 170 of the master brake cylinder 1 and the chamber of the pressure medium storage container 2 and is a normally closed, 20. The brake system according to claim 1, 13. The method according to any one of claims 1 to 12,
By providing the pressure supply device 5 reversibly connected to the first pressure chamber 17, 170, a hydraulic connection 53 is provided with an electrically actuated, in particular normally closed, valve 52 The brake system comprising: 14. The method according to any one of claims 1 to 13,
Characterized in that the electrically controllable pressure supply device (5) is in the form of a single circuit electrohydraulic actuator (35, 36, 37).

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