Foot brake module of an electro-pneumatic braking system of a motor vehicle

Description

[0001] The invention relates to a foot brake module of an electropneumatic brake system of a motor vehicle with at least two pneumatic brake circuits, which can be actuated by means of a brake pedal and which has a pneumatic part with a pneumatic brake control valve and an electrical part with at least one electrical switch and at least one electronic displacement sensor.

[0002] In an electropneumatic braking system of a motor vehicle, the brake pressure levels in the two brake circuits can be controlled either electronically or pneumatically. Typically, the brake pressures are controlled electronically during normal operation and only switch to pneumatic control when a malfunction occurs in the electronic brake control system.

[0003] In a pneumatic brake control valve, a brake control pressure is set from a supply pressure applied on the input side depending on the travel of a tappet connected to the brake pedal of the motor vehicle, which brake control pressure is introduced as pilot pressure into a pneumatic relay valve of the relevant brake circuit and is converted there into a brake pressure effective in the associated wheel brake cylinders.

[0004] The aforementioned electrical switch operates electromechanically and is connected to the plunger of the foot brake module via a cam or other component. When the brake pedal is depressed, the switch is activated after a certain amount of free travel has been overcome, thereby detecting the beginning of a braking process and activating the electronic control of the brake pressures when the vehicle's electrical system or ignition is switched off. Furthermore, the position of the plunger when the switch is actuated is also used as a reference position for the aforementioned electronic travel sensor.

[0005] The electronic travel sensor is typically contactless and is influenced inductively or magnetically by a ferromagnetic or permanent-magnetic signal transmitter, which is directly or indirectly attached to the tappet. The travel sensor serves as a brake value transmitter and measures the braking travel of the tappet, which is then transmitted, for example, in the form of a pulse-width-modulated signal to an electronic control unit of the electronic brake control system. The electronic control unit feeds a corresponding control current into an electromagnetic relay valve of the relevant brake circuit, where it is converted into brake pressure effective in the associated wheel brake cylinders.

[0006] Compared to pneumatic control of the brake pressures, electronic control of the brake pressures has the advantage of a faster response to a changed actuation position of the brake pedal and a more precise dosage of the brake pressures or the effective braking forces.

[0007] WABCO Standard GmbH publication no. 815_268, entitled "EBS - Electronically Controlled Braking System in the O 580 Coach," describes the design and operation of an electropneumatic braking system and a foot brake module of the WABCO 480 002 xxx 0 series. The foot brake module, referred to there as a brake signal transmitter, comprises a pneumatic section with two pneumatic brake control valves and an electrical section with an electrical switch and two electronic displacement sensors. The brake control valves and the displacement sensors are each assigned to a different one of the two brake circuits. The travel signals from the displacement sensors are transmitted as pulse-width modulated signals to a central module of the electronic brake control unit.

[0008] WABCO Standard GmbH's publication no. 815 020 208 3, entitled "EBS3 - Electronic Braking System," describes the design and operation of several embodiments of an electropneumatic braking system and a foot brake module of the WABCO 480 003 xxx 0 series. The foot brake module, referred to there as a brake signal transmitter, comprises a pneumatic section with two pneumatic brake control valves and an electrical section with an electrical switch and two electronic displacement sensors. The brake control valves and the displacement sensors are each assigned to a different one of the two brake circuits. The travel signals from the displacement sensors are transmitted as pulse-width modulated signals to a central module of the electronic brake control unit.

[0009] In DE 10 2014 010 815 A1, the applicant describes a foot brake module, referred to therein as an electropneumatic control valve, comprising two pneumatic brake control valves, an electrical switch, and an electronic displacement sensor. The switch and the displacement sensor are arranged in an electronics housing that is attached to the side of the foot brake module housing. The switch can be actuated by a pressure plate attached to the plunger via a pivoting angle lever. The displacement sensor is influenced by a signal transmitter that is longitudinally displaceable between the foot brake module housing and the electronics housing and is attached to the pressure plate. Evaluation electronics, in which the sensor signal from the displacement sensor is converted into a pulse-width modulated signal, are arranged directly adjacent to the switch and the displacement sensor in the electronics housing.

[0010] To date, the displacement sensors have been so-called AMR sensors (AMR effect = anisotropic magnetoresistive effect), which do not sense the change in the field strength of a magnetic field but rather the change in the direction of a magnetic field, and whose evaluation electronics, as in the previously described foot brake module, are arranged separately near the sensors.

[0011] US2018001879A1 relates to an electronic braking system for a braking system of a commercial vehicle, comprising a brake value transmitter which has at least one sensor for detecting positions of a brake pedal actuated by the driver of the commercial vehicle and at least one valve which can be mechanically actuated via the brake pedal.

[0012] US2002046616A1 discloses a method for generating kick-down signals for an automatic shifting device by means of an accelerator pedal device having at least one pedal element which is to be moved in at least one pivot point and adjusted by means of at least one movement sensor element.

[0013] DE102014013756B3 relates to an electrical equipment of a vehicle with an at least partially electric braking and steering device comprising an electric or electro-mechanical steering device with or without a continuous mechanical connection between a steering wheel and a steering gear as well as with an electronic steering control device and an electric steering actuator.

[0014] DE102007035326A1 discloses a braking device, in particular an electrically operated braking device for motor vehicles, comprising a brake pedal sensor for detecting a braking request exerted on a brake pedal and a control unit connected to the brake pedal sensor, wherein at least two brake pedal sensors are provided, each of which is assigned to a control unit, and the control units are connected to one another via a data connection.

[0015] Based on the described embodiments of the known foot brake modules, the object of the present invention was to provide a foot brake module of an electropneumatic brake system of the type mentioned at the outset, which is constructed in a way that is as low-wear, simple, cost-effective and space-saving as possible without limiting the operational reliability of the brake system.

[0016] This object is achieved by a foot brake module having the features of claim 1. Advantageous further developments of this foot brake module are defined in the dependent claims.

[0017] Accordingly, the invention relates to a foot brake module of an electropneumatic brake system of a motor vehicle with at least two pneumatic brake circuits, which can be actuated by means of a brake pedal and which has a pneumatic part with a pneumatic brake control valve and an electrical part with at least one electrical switch and at least one electronic displacement sensor.

[0018] To solve the problem, this foot brake module is provided with an electrical switch that operates without contact and with two travel sensors, each of which has a separate power supply and is connected to different electronic control units.

[0019] The contactless design of the switch means it is largely wear-free and therefore has a long service life. Due to their separate power supplies and connection to different electronic control units, the travel sensors can be operated independently of one another, and their sensor signals can be evaluated independently of one another. This has the advantage that the two travel sensors can be used redundantly. If one of the two travel sensors fails, the sensor data from the other travel sensor is available to control the relay valves of one or more of a vehicle's brake circuits. Furthermore, thanks to the separate power supplies and separate evaluation of the sensor signals from the two travel sensors, one of the two brake control valves can be dispensed with without reducing the operational reliability of the vehicle's braking system.Finally, the use of two control units further improves the operational reliability of the braking system.

[0020] The aforementioned switch of the foot brake module is preferably magnetic field-sensitive and can be designed either as a reed switch or as a Hall sensor, each of which is assigned a single, shared permanent magnet, attached directly or indirectly to a plunger connected to the brake pedal, as a signal transmitter. In a reed switch, contact blades made of a nickel-iron alloy are fused into a glass tube. These contact blades are activated by a variable magnetic field, namely, they are brought into contact with one another or separated from one another. A Hall sensor utilizes the so-called Hall effect, in which the so-called Hall voltage occurs in a current-carrying conductor located in a stationary magnetic field, perpendicular to the current flow and the direction of the magnetic field. In a variable magnetic field, the Hall voltage changes accordingly.The variable magnetic field is created when the brake pedal is actuated by the magnetic field of the single, common permanent magnet attached to the tappet, which passes the respective sensor.

[0021] Furthermore, it can be provided that the aforementioned switch and the two position sensors can be actuated by means of a single, shared permanent magnet attached to the plunger. This allows the manufacturing costs of the foot brake module to be reduced.

[0022] The at least one of the two displacement sensors is also preferably designed as a Hall sensor, to which a single common permanent magnet, which is attached directly or indirectly to a tappet in actuating connection with the brake pedal, is assigned as a signal transmitter.

[0023] To achieve trouble-free operation and compact dimensions, another embodiment of the invention can provide for a dedicated evaluation electronics unit to be arranged on a sensor chip of the displacement sensor, in which the measured value of the respective displacement sensor can be converted into a digital data transmission signal. This data transmission signal can be, for example, a pulse-width modulated signal, but other data transmission forms are also possible.

[0024] According to a first embodiment of the described foot brake module according to the invention, it is provided that, in addition to an electrical switch, two electronic travel sensors and a pneumatic brake control valve are present, and that the sensor signals of the two electronic travel sensors can be used, after their evaluation, in the respectively assigned control unit for controlling at least one pneumatic brake circuit.

[0025] During the aforementioned evaluation of the sensor signals from the two travel sensors, it is possible to determine two travel values ​​from these sensor signals. Using these two travel values, the accuracy of the travel value intended for brake pressure adjustment is improved by calculating an arithmetic mean. This averaged travel value is then used to control the relay valves of one or more brake circuits of a vehicle.

[0026] The control of one or both of a vehicle's brake circuits can be switched to pneumatic control via the existing single brake control valve if the two electronic position sensors are defective or deliver implausible values. This means that if the electronic controls of both brake circuits fail, the pneumatic control is activated, allowing the vehicle in question to be safely braked via this brake circuit and its pneumatic control using the existing brake control valve. By omitting the previously used second pneumatic brake control valve, material and manufacturing costs are saved, and the dimensions of the foot brake module are reduced due to the reduced height of the housing.

[0027] According to a second embodiment of the described foot brake module not according to the invention, it is provided that, in addition to an electrical switch, only one electronic travel sensor and only one pneumatic brake control valve are present, and that the sensor signals of the only one travel sensor can be used, after their evaluation in the associated control unit, to control at least one pneumatic brake circuit.

[0028] If the electronic control for one or more brake circuits fails, the pneumatic control is activated, allowing the affected vehicle to be safely braked using the single existing brake control valve. By omitting a second electronic travel sensor and a second pneumatic brake control valve compared to conventional foot-operated brake modules, material and manufacturing costs are saved, and the dimensions of the foot-operated brake module are reduced due to the reduced height of the housing.

[0029] The invention is explained in more detail below with reference to three exemplary embodiments shown in the accompanying drawing. Fig. 1 a first embodiment of a foot brake module according to the invention in a schematic view, Fig. 2 a second embodiment of a foot brake module not according to the invention in a schematic view, and Fig. 3 a known foot brake module in a schematic view.

[0030] In Fig. 3 A schematic view of a foot brake module 2 of an electropneumatic braking system for a vehicle with at least two pneumatic brake circuits, known for example from the aforementioned WABCO publication no. 815 020 208 3, is shown. The foot brake module 2 has a pneumatic part with two pneumatic brake control valves 16, 20 and an electrical part with an electrical switch 10 and two electronic displacement sensors 12, 14, which are arranged in a common housing 4. The two brake control valves 16, 20 can be actuated by a brake pedal (not shown) via a tappet 6 against the restoring force of a compression spring 8 designed as a helical spring.

[0031] The first brake control valve 16 has, on the inlet side, a pneumatic connection p1 provided with a first filter element 18 for a supply pressure line of the first brake circuit, and on the outlet side, a pneumatic connection p4 for a brake control line of the first brake circuit. Furthermore, a vent line 24 connected to the output side of the first brake control valve 16 leads to a pneumatic vent outlet p3, which is connected to the environment via a silencer 26. The second brake control valve 20 has, on the inlet side, a pneumatic connection p2 provided with a second filter element 22 for a supply pressure line of the second brake circuit, and on the outlet side, a pneumatic connection p5 for a brake control line of the second brake circuit. Furthermore, the vent line 24, which is also connected to the output side of the second brake control valve 20, leads to the pneumatic vent outlet p3.

[0032] With increasing depression of the brake pedal, which causes a displacement of the tappet 6 in the direction of the two brake control valves 16, 20 (in Fig. 3 downwards), an increasingly high brake control pressure is set at the output-side pneumatic connections p4, p5 by means of the two brake control valves 16, 20. These brake control pressures are converted into the brake pressure effective in the wheel brake cylinders of the respective brake circuit during the pneumatic control of the brake pressures in a pneumatic relay valve 80, 81 of each of the two brake circuits. The line connections from the two output-side pneumatic connections p4, p5 of the foot brake module 2 to the respectively assigned relay valves 80, 81 are not shown separately for the sake of clarity, but are known per se to those skilled in the art.

[0033] Accordingly, when the brake pedal is released, which causes the tappet 6 to move away from the brake control valves 16, 20 (in Fig. 3 upwards) causes, in the case of a pneumatic control, the brake control pressures at the output-side pneumatic connections p4, p5 are reduced again, which leads to lower brake pressures effective in the assigned wheel brake cylinders in the assigned relay valves 80, 81 of the two brake circuits.

[0034] The foot brake module 2 has several electrical connections e1 to e6, to which external electrical lines 30, 36, 37, 38, 41, 43 are connected. These external electrical lines 30, 36, 37, 38, 41, 43 are connected to a common control unit 70, which, on the one hand, serves to supply power to all electrical components of the foot brake valve 2, but, on the other hand, is also responsible for receiving and evaluating switching signals and sensor signals from the foot brake module 2. Using the aforementioned received information, the common control unit 70 finally serves to electrically control the two aforementioned relay valves 80, 81, which set the required brake pressures at the wheel brake cylinders (not shown) of the vehicle.

[0035] This shows that Fig. 3 The known foot brake module 2 shown has a first electrical input terminal e1 for supplying voltage to two displacement sensors 12, 14 and an electrical switch 10. A first external voltage supply line 30 is connected to this first electrical input terminal e1, which is supplied with a sufficiently high electrical voltage by the common control unit 70. This supplied electrical voltage is supplied via a first internal line branch 31 to an evaluation electronics unit 27 of the first displacement sensor 12 and via a second internal line branch 32 to an evaluation electronics unit 28 of the second displacement sensor 14. Furthermore, a third internal line branch 33 of the voltage supply leads from the first internal line branch 31 to the aforementioned switch 10.The electrical switch 10 in this known foot brake module 2 is electromechanically effective and is actuated by means of a cam 11, shown only schematically, arranged on the tappet 6.

[0036] In addition, the known foot brake module 2 features a second electrical input terminal e2 for the electrical ground potential (GND), to which a second external voltage supply line 38 is connected. This second external voltage supply line 38 is connected to the common control unit 70 and is supplied with the electrical ground potential by the latter. Within the foot brake module 2, a first internal voltage supply line 39 for the ground potential and a second internal voltage supply line 40 for the ground potential are connected to the second electrical input terminal e2 for the electrical ground potential. These connect the evaluation electronics 27, 28 of the two displacement sensors 12, 14 to the ground potential.

[0037] The evaluation electronics 27 of the first travel sensor 12 is connected via an internal first travel signal line 42 to an output connection e5 for the first travel sensor 12 on the foot brake module 2, and the evaluation electronics 28 of the second travel sensor 14 is connected via an internal second travel signal line 44 to an output connection e6 for the second travel sensor 14 on the foot brake module 2. A first external travel signal line 41 and a second external travel signal line 43 are connected to each of these two output connections e5, e6, respectively. The sensor signals from the two travel sensors 12, 14 are sent to the common control unit 70 via these two external travel signal lines 41, 43.

[0038] The switch 10 of the foot brake module 2 has two contact points that can be subjected to electrical voltage, which are connected via a first internal switching signal line 34 to a first switch output terminal e3 and via a second internal switching signal line 35 to a second switch output terminal e4 on the foot brake module 2. A first external switch signal line 36 for the switching signal and a second external switch signal line 37 for the switching signal of the switch 10 are connected to each of these two switch output terminals e3, e4.

[0039] As the circuit diagram of the foot brake module 2 illustrates, an electrical voltage is applied to one of the two switch output terminals e3, e4 depending on the axial position of the plunger 10. This provides the common control unit 70 with information about whether the foot brake module 2 is being actuated by a person using the plunger 6 or not. Accordingly, when the brake pedal and the plunger 6 are actuated, the switch 10 is moved to its second closed position after overcoming a free travel. As a result, the common control unit 70 detects an incipient braking process and, when the vehicle's electrical system or ignition is switched off, the electronic control of the brake pressures is activated. This essentially wakes up the common control unit 70. Furthermore, the setting position of the plunger 6 when the switch 10 is actuated is also used as a reference position for the electronic travel sensors 12, 14.

[0040] The electronic displacement sensors 12, 14 serve as brake value transmitters and can be assigned to the two brake circuits or to a different one of the two brake circuits. In this known foot brake module 2, the two displacement sensors 12, 14 are designed as contactless AMR sensors (AMR effect = anisotropic magnetoresistive effect) and measure the braking travel of the plunger 6. A permanent magnet 9, which is attached to the plunger 6, serves as the signal transmitter for the two displacement sensors 12, 14. The raw signal from the displacement sensors 12, 14 is converted into a pulse-width modulated signal in the evaluation electronics 27, 28 arranged on a circuit board. This signal is forwarded via the output terminals e5, e6 to the common control unit 70 of an electronic brake control system.From the common control unit 70, corresponding control currents are then introduced into the aforementioned, associated electromagnetic relay valves 80, 81 of the respective brake circuits and converted there into a brake pressure effective in the associated wheel brake cylinders.

[0041] During normal operation, the brake pressures are controlled electronically and only switched to pneumatic control when a malfunction occurs in the electronic brake control system. Disadvantages of this known foot brake module 2 are the electromechanical design of the switch 10, which is subject to mechanical wear; the shared power supply of the travel sensors 12, 14, which leads to the failure of both travel sensors 12, 14 in the event of a malfunction in the control electronics; and the presence of the two brake control valves 16, 20, even though they are not used during normal operation.

[0042] In contrast, the Figur 1 In the illustrated embodiment of the foot brake module 2.1 having the features of the invention, it is provided that the electrical switch 10' there is effective in a contactless manner. In addition, the foot brake module 2.1 according to Fig. 1 two displacement sensors 12', 14', which are supplied with electrical voltage and ground potential independently of one another by a respective assigned separate control unit 71, 72, and whose sensor measured values ​​are each received and evaluated separately by these two control units 71, 72. However, the two control units 71, 72 communicate, among other things, the respectively determined displacement measured values ​​to one another via a communication line 53, calculate arithmetic mean values ​​from these if necessary, and use these to generate control currents for the relay valves 80, 81 connected to the two control units 71, 72, respectively, for adjusting brake pressures in the brake circuits of a vehicle. For this purpose, in this exemplary embodiment, the two control units 71, 72 are each connected to the two relay valves 80, 81 via control lines 84, 85; 86, 87.

[0043] The Fig. 1 The illustrated foot brake module 2.1 according to the invention has a first input terminal e7 for an electrical voltage, which is provided by the first control unit 71 via a first external voltage supply line 50. This electrical voltage passes from the first input terminal e7 via a first internal line branch 60 to the evaluation electronics 27 of the first displacement sensor 12' and via a second internal voltage line branch 61 to the switch 10'.

[0044] To supply the first displacement sensor 12' with the electrical ground potential, an input terminal e8 for the electrical ground potential is provided on the foot brake module 2.1, to which the evaluation electronics 27 is connected via a first internal ground potential line 62. The electrical ground potential is provided via a second external voltage supply line 51 connected to the aforementioned input terminal e8, which is connected to the first control unit 71.

[0045] In addition, the first travel sensor 12' is connected via a first internal travel signal line 64 to a first output connection e9 on the foot brake module 2.1, to which a first external travel signal line 52 is also connected, which is connected to the first control unit 71.

[0046] The foot brake module 2.1 according to Fig. 1 In contrast to the known foot brake module according to Fig. 3 a second input terminal e11 for an electrical voltage, which is provided by the second control unit 72 via a second external voltage supply line 55. This electrical voltage passes from said second input terminal e11 via a third internal line branch 65 to the evaluation electronics 28 of the second displacement sensor 14'.

[0047] To supply the second travel sensor 14' with the ground potential, a second input terminal e12 for the electrical ground potential is provided on the foot brake module 2.1, to which the evaluation electronics 28 of the second travel sensor 14' is connected via a third internal ground potential line 66. The electrical ground potential is provided via a fourth external voltage supply line 56 connected to the aforementioned input terminal e12, which is connected to the second control unit 71.

[0048] Furthermore, the second travel sensor 14' is connected via a second internal travel signal line 67 to a second output terminal e13 on the foot brake module 2.1, to which a second external travel signal line 57 is also connected, which is connected to the second control unit 72. This provides an autonomous electronic control for each of the two brake circuits of a vehicle, significantly reducing the probability of failure of the electronic control for both brake circuits.

[0049] The switch 10' of the foot brake module 2.1 according to Fig. 1 is connected with its output contact via an internal switching signal line 63 to an output terminal e10 for the switch 10'. The switch signal present there is made available to the first control unit 71 and the second control unit 72 via an external switch signal line 68 connected to the output terminal e10. However, due to the existing communication line 53 between the two control units 71, 72, the external switching signal line 63 can also be routed to only one of the two control units 71, 72.

[0050] The switch 10' of the foot brake module 2.1 according to the invention according to Fig. 1 is magnetic field sensitive and can be designed either as a reed switch or as a Hall sensor, to which a permanent magnet 7 attached to the plunger 6 is assigned as a signal generator.

[0051] For the foot brake module 2.1 according to Fig. 1 In addition to the electrical switch 10', the two electronic travel sensors 12', 14', and only the first pneumatic brake control valve 16 are present. The two travel sensors 12', 14' are assigned to both brake circuits and operate redundantly. Thus, should one of these travel sensors 12', 14' fail or deliver an implausible sensor signal, the vehicle's braking system can still be controlled without problems.

[0052] The single brake control valve 16 is assigned to the first brake circuit, but it can also be assigned to both brake circuits of a vehicle.

[0053] In addition, the control of one brake circuit can be switched to pneumatic control via the existing brake control valve 16, provided this is assigned to the brake circuit with the failed electronic control. Otherwise, the vehicle in question can still be safely braked via the other brake circuit and its electronic control.

[0054] If the electronic control units 71, 72 of both brake circuits fail, the pneumatic control of the first brake circuit is activated, so that the vehicle in question can still be safely braked via this brake circuit and its pneumatic control via the existing brake control valve 16. By omitting the second pneumatic brake control valve 20 provided in the prior art, material and manufacturing costs are saved, and the dimensions of the foot brake module 2.1 are reduced due to the reduced height of the housing 4'.

[0055] In the non-inventive foot brake module 2.2 according to Fig. 2 In addition to the electrical switch 10', only the first electronic travel sensor 12' and only the first pneumatic brake control valve 16 are present. This foot brake module 2.2, not according to the invention, is connected to only a single control unit 73 via the explained electrical lines 50, 51, 52, 68, and this third control unit 73 is connected via control lines 88, 89 to associated relay valves 80, 81 of two brake circuits in order to supply them with control currents as needed for adjusting brake pressures.

[0056] The single travel sensor 12' is assigned to both brake circuits of a vehicle, and the brake control valve 16 is assigned to the first brake circuit. If the electronic control of both brake circuits fails, the pneumatic control of the first brake circuit is activated, so that the vehicle in question can still be safely braked via this brake circuit and its pneumatic control via the existing brake control valve 16. By omitting the second electronic travel sensor 14' and the second pneumatic brake control valve 20, material and manufacturing costs are saved, and the dimensions of the foot brake module 2.3 are reduced due to the reduced height of the housing 4'.

[0057] For the foot brake module 2.2 according to Fig. 2It is also provided that the electrical switch 10' and the single travel sensor 12' are actuated contactlessly by means of a single magnet 5, which is attached to the plunger 6. This further reduces the manufacturing costs of the foot brake module 2.2. List of reference symbols (part of the description)

[0058] 2 Foot brake module (prior art) 2.1 Foot brake module (first embodiment according to the invention) 2.2 Foot brake module (second embodiment according to the invention) 2.3 Foot brake module (third embodiment according to the invention) 4, 4' Housing 5 Common permanent magnet 6 Plunger 7 First permanent magnet 8 Compression spring, coil spring 9 Second permanent magnet 10 Electrical switch (known) 10 Electrical switch (according to the invention) 11 Actuating cam on the plunger 12 First electronic travel sensor (known) 12 First electronic travel sensor (according to the invention) 14 Second electronic travel sensor (known) 14 Second electronic travel sensor (according to the invention) 16 First pneumatic brake control valve 18 First filter element 20 Second pneumatic brake control valve 22 Second filter element 24 Vent line 26 Silencer 27First evaluation electronics 28Second evaluation electronics 30First external power supply line (state of the art) 31First internal line branch of thePower supply (state of the art) 32Second internal line branch of the power supply (state of the art) 33Third internal line branch of the power supply (state of the art) 34First internal switch signal line (state of the art) 35Second internal switch signal line (state of the art) 36First switch signal line (state of the art) 37Second switch signal line (state of the art) 38External ground potential line (state of the art) 39First internal ground potential line (state of the art) 40Second internal ground potential line (state of the art) 41First external path signal line (state of the art) 42First internal path signal line (state of the art) 43Second external path signal line (state of the art) 44Second internal path signal line (state of the art) 50First external power supply line 51First external ground potential line 52First external Path signal line 53Communication line 55Second external power supply line 56SecondExternal ground potential line 57 Second external travel signal line 60 First internal line branch of the power supply 61 Second internal line branch of the power supply 62 First internal ground potential line 63 Internal switch signal line 64 First internal travel signal line 65 Third internal line branch of the power supply 66 Second internal ground potential line 67 Second internal travel signal line 68 External switch signal line 70 Common control unit (state of the art) 71 First control unit 72 Second control unit 73 Third control unit 80 Relay valve of a first brake circuit 81 Relay valve of a second brake circuit 84 Control line from control unit 71 to relay valve 80 85 Control line from control unit 71 to relay valve 81 86 Control line from control unit 72 to relay valve 80 87 Control line from control unit 72 to relay valve 81 88Control line from control unit 73 to relay valve 80 89Control line from control unit 73 to relay valve 81 e1Input connection voltagefor switch 10 and displacement sensors 12, 14 e2 Input connection ground potential for both displacement sensors 12, 14 e3 First switch output connection e4 Second switch output connection e5 Output connection for first displacement sensor 12 e6 Output connection for second displacement sensor 14 e7 Input connection voltage for switch and first displacement sensor 12' e8 Input connection ground potential for first displacement sensor 12' e9 Output connection for first displacement sensor 12' e10 Output connection for switch 10' e11 Input connection voltage for second displacement sensor 14' e12 Input connection ground potential for second displacement sensor 14' e13 Output connection for second displacement sensor 14' p1 Connection for supply pressure (first brake circuit) p4 Connection for brake control pressure (first brake circuit) p2 Connection for brake control pressure (second Brake circuit) p3Vent outlet p5Connection for supply pressure (second brake circuit) SDistance (measured with displacement sensor) UElectrical voltage (at displacement sensor)

Claims

1. Foot brake module (2.1, 2.2, 2.3) of an electropneumatic brake system of a motor vehicle, comprising at least two pneumatic brake circuits and a plunger (6), which foot brake module can be actuated by means of a brake pedal and which has a pneumatic portion having a pneumatic brake control valve (16) and an electrical portion having at least one electrical switch (10') and at least one electronic travel sensor (12', 14'), the electrical switch (10') acting in a contactless manner, and the foot brake module (2.1) having two travel sensors (12', 14'), the two travel sensors (12', 14') each having a separate power supply and being connected to different electronic control units (71, 72),characterized in that the switch (10') and the two travel sensors (12', 14') can only be actuated by means of a single, common permanent magnet (5; 7) which is attached to the plunger (6).

2. Foot brake module according to claim 1, characterized in that the switch (10') is sensitive to magnetic fields.

3. Foot brake module according to claim 2, characterized in that the switch (10') is designed as a reed switch, and a single, common permanent magnet (5; 7) attached directly or indirectly to the plunger (6) in actuating connection with the brake pedal is assigned to said switch as a signal generator.

4. Foot brake module according to claim 2, characterized in that the switch (10') is designed as a Hall sensor, and a single, common permanent magnet (5; 7) attached directly or indirectly to the plunger (6) in actuating connection with the brake pedal is assigned to said switch as a signal generator.

5. Foot brake module according to any of claims 1 to 4, characterized in that the at least one travel sensor (12', 14') of the two travel sensors (12', 14') is designed as a Hall sensor, to which a single, common permanent magnet (5; 7) attached directly or indirectly to a plunger (6) in actuating connection with the brake pedal is assigned as a signal generator.

6. Foot brake module according to claim 5, characterized in that, on a sensor chip of the travel sensor (12', 14'), a corresponding evaluation electronics unit (27, 28) is arranged, in which the measured value can be converted into a digital data transmission signal.

7. Foot brake module according to any of claims 1 to 6, characterized in that, in the foot brake module, in addition to an electrical switch (10'), there are two electronic travel sensors (12', 14') and a pneumatic brake control valve (16), and in that, after being evaluated, the sensor signals of the two electronic travel sensors (12', 14') can be used in the respectively assigned control unit (71, 72) to control at least one pneumatic brake circuit.