DE102006036311A1 - Braking force generator for a hydraulic vehicle braking system comprises a pedal counter force simulation unit having a simulator piston which is displaced in a cylinder bore of a housing along a bore longitudinal axis - Google Patents

Abstract

Braking force generator (10) comprises a pedal counter force simulation unit having a simulator piston (26) which is displaced in a cylinder bore of a housing (12) along a bore longitudinal axis. Three cylinder bores are arranged next to each other in the housing. An independent claim is also included for a hydraulic vehicle braking system with the above generator. Preferred Features: One cylinder bore with a first piston arrangement (22) and another cylinder bore with a second piston arrangement (24) are arranged next to each other.

Description

The The present invention relates to a braking force generator for a hydraulic Motor vehicle brake system with a housing, two piston arrangements, wherein a first piston assembly in a first cylinder bore of the housing along a first bore longitudinal axis is displaceably received and wherein a second piston assembly in a second cylinder bore along a second bore longitudinal axis is displaceably received, a counter-pedal force simulation device and a force input member which can be coupled to a brake pedal or is coupled, wherein upon movement of the force input element the pedal counter-force simulation device is actuated and in accordance with the Movement of the force input member, the first and the second piston assembly are relocatable.

Such a braking force generator is for example from the document DE 37 15 209 A1 known. This includes a tandem master cylinder arrangement in which the two piston assemblies act in the adjacent cylinder bores which are hydraulically coupled together. During braking, a pedal actuating force is exerted on the first piston via a brake pedal, via which the brake pressure is then generated in the hydraulic brake system. In other words, in a braking system equipped with this braking force generator, the hydraulic brake pressure necessary for applying the wheel brake to the vehicle is generated purely mechanically with the brake cylinder arrangement alone.

adversely affects such a directly coupled braking system, that the driver through his operation action on the brake pedal in any case the hydraulic pressure at the wheel brakes affected. As long as this supports the braking situation, this is not a problem. Once the driver but based on the actual Brake situation reacts incorrectly, for example, by too much or too little brake pressure einsteuert, the braking behavior, in particular the braking distance, as well as the directional stability of the vehicle will be deteriorated, which in the worst case can lead to an accident.

One Another disadvantage of this arrangement is that the two Piston assemblies in the corresponding cylinder bores hydraulically with each other are coupled. This results in the problem that in case of malfunction, especially in the case of a leakage in the immediate vicinity of one Brake pedal operation Moving piston assembly, no reliable control of this downstream Piston arrangement and the hydraulic vehicle brake system is more possible.

Furthermore, it is off DE 103 11 060 B4 a braking force generator with a tandem piston assembly with two in a common housing bore successively recorded piston assemblies known. The two piston arrangements define two pressure chambers in the housing, which are in fluid communication with the hydraulic brake circuit. A displacement of the piston assemblies is carried out in normal operation via an additional servo pressure circuit. This means that an actuation of the brake pedal is detected and actuated in accordance with the pedal actuation of the servo pressure circuit and, accordingly, the series-connected piston assemblies are displaced to build up a hydraulic pressure. However, the pedal actuation force actually applied to the brake pedal "fizzle out" in such a normal mode of operation However, to provide the driver with a familiar pedaling sensation, a counter pedal force simulator is provided which is also connected in series with the tandem piston assembly so that an in However, these relatively large dimensions of the braking force generator counteract the prevailing tendency in modern motor vehicle endeavor, according to which the components used should occupy as little space as possible to make the passenger compartment as large as possible and to the variety of other components in the engine compartment compact to accommodate.

It It is therefore an object of the present invention to provide a braking force generator the type described at the beginning with greatly reduced external dimensions provide.

These Task is characterized by a braking force generator of the beginning Sort of solved, wherein it is further provided that the pedal counter-force Simualtionseinrichtung having a simulator piston in a third cylinder bore of the housing displaceable along a third bore longitudinal axis is included, wherein the first, second and third cylinder bore in the case are arranged side by side.

According to the invention - in contrast to the arrangement according to DE 103 11 060 B4 - The two piston assemblies arranged in separate cylinder bores.

These cylinder bores are next to each other. In addition, the pedal counter-force simulation device is arranged with its associated cylinder bore adjacent to the two cylinder bores receiving the first and second piston assembly. Overall, an extremely compact structure of a piston assembly results despite their compact and space-saving design with regard to the braking effect meets the same requirements, such as the arrangement according to document DE 103 11 060 B4 , The essential advantage of the invention is that the housing containing the three cylinder bores can be made considerably shorter in the direction of the bore longitudinal axes than in the prior art, where the pedal counter-force simulation device is arranged in the axial direction in series with the piston assemblies.

A Development of the invention provides that the first, second and third bore longitudinal axis essentially parallel to each other. This allows the in the individual cylinder bores guided piston assemblies and the simulation piston displaced in substantially the same direction so that when pressed no tilting or tilting moments can occur.

Regarding the arrangements of the individual bore longitudinal axes to each other there different according to the invention Options. A first variant of the invention provides that the first, second and third bore longitudinal axis lying essentially in one plane. It can be provided that the first cylinder bore with the first piston assembly and the second cylinder bore adjacent to the second piston assembly are arranged and that the third cylinder bore with the simulator piston arranged next to the pair of cylinder bores for the piston assemblies is. In this embodiment are the first and second cylinder bore, which the piston assembly record for brake pressure generation, in the immediate spatial Close to each other arranged and the pedal counter-force simulation device next to this bore pair formed from first and second cylinder bore. Alternatively, it may be provided that the third cylinder bore with the simulator piston between the first cylinder bore with the first piston assembly and the second cylinder bore with the second piston assembly is arranged. This variant can be configured in particular so that the force input element of the Bremskrafterzeugers in axial alignment with the bore longitudinal axis the third cylinder bore is displaced so that over the Force input element in the braking force generator initiated operating force acting on the center of the simulator piston. This can be a Occurrence of shear forces and tilting moments further suppressed become.

alternative to an arrangement of the individual bore longitudinal axes in one and the same Level can These are also in different levels. An advantageous embodiment The invention provides in this context that the first, second and third bore longitudinal axis in an axis orthogonal section looks at the corners of a triangle, preferably an isosceles triangle, in particular one form equilateral triangle. In other words, the intersections lie the bore longitudinal axes with the achsorthogonal plane all on a circle. In the Arrangement in which they form the corners of an equilateral triangle, let yourself a braking force generator with the smallest possible dimensions in the direction transverse to the bore longitudinal axes to reach.

As will be explained in detail below and at the outset according to the prior art DE 103 11 060 B4 has been explained, it is possible that in a normal operating situation, only the pedal counter-force simulation device is actuated by the brake pedal. In an emergency operating situation, however, each of the piston arrangements must also be accessible by the brake pedal actuation. In order to be able to achieve this in the inventive arrangement of the cylinder bores in the housing, a development of the invention provides that with the force input member a guided in the housing actuating piston is connected, wherein the actuating piston has an actuating end face which is cut by each of the piston longitudinal axes. In other words, the actuating force introduced into the braking force generator via the force input element is transmitted to the actuating piston. This transmits then over its end face the force in the normal operation case on the pedal counter-force simulation device and in case of emergency on the piston assemblies for the mechanical generation of a braking force. The actuating piston may be formed as a separate component or integral with the force input member.

Further can be provided that the actuating piston dimensioned so is that he is in an achsorthogonal projection screen him facing end faces the first and second piston assembly and the simulator piston encloses. Thereby is guaranteed that the actuating piston indeed all three pistons, namely the simulator piston and the two piston assemblies for brake pressure generation, reliable in emergency situations actuate can.

In order to determine the degree of brake pedal actuation, a sensor may be mounted directly on the brake pedal, which can detect the deflection of the brake pedal, the pedal travel to be laid back and / or the operating speed of the brake pedal. Alternatively, however, may also be provided a position detection device for detecting the current operating position of the force input element. In this context, an embodiment variant of the invention provides that the position detection device a mounted on the actuating piston movable component and arranged on the housing stationary component. For example, the movable component may be a permanent magnet and the stationary component may be a Hall sensor.

Around in emergency operation a reliable activity the pedal counter-force simulation device and to allow the piston arrangements provides a development of the invention that the first piston assembly and the second piston assembly and the simulator piston, respectively one to the actuating piston have in the direction of the respective bore longitudinal axis protruding piston plunger, wherein the actuating piston in the case of operation at least on the piston plunger of the Simulator piston attacks to this in the third cylinder bore to move.

As already executed, is in normal operation only an operation of the simulator piston he wishes. The piston assemblies for brake pressure generation are otherwise actuated, for example, by a servo pressure circuit described in more detail below. Therefore, in normal operation, a power transmission from the actuating piston to avoid the piston arrangements. To achieve this, see a development of the invention that in a starting position the piston plunger of Simulator piston with its end face on the actuating piston is present and that a clearance between the piston tappets the is provided first and second piston assembly and the actuating piston. The clearance is chosen that even at a delayed Response of the servo pressure circuit in normal operation no contacting the Piston plunger through the actuating piston occurs.

Regarding sees the design of the pedal counter-force simulation device an embodiment variant the invention that the simulator piston with a simulation spring on the actuating piston too tense. The simulation spring contributes to the "synthetically" generated pedal drag. Likewise, but also in addition or alternatively a fluidic system in the pedal backlash simulator be provided, for example, a hydraulic or pneumatic system with a throttle.

A Development of the invention provides in connection with the pedal counter-force simulation device before that provided in the third cylinder bore a separating piston That is with a biasing spring towards the simulator piston is biased against a stop, with the simulation spring is supported on the separating piston, wherein the separating piston a completed by the simulator piston simulation chamber separated from a security chamber. The use of such Separating piston with a safety chamber offers the advantage that the pedal counter-force simulation device in emergency operation, in essentially the entire pedal force for actuating the Utilized piston arrangements should be, fast and reliable can be disabled. This will also be discussed in the following Detail received.

As already indicated several times, sees a preferred embodiment the invention that the first and second piston assembly by means a hydraulic servo pressure circuit is effectively displaced by braking. In accordance with the over the position detecting device is detected pedal operation the servo pressure circuit is controlled, which then the first and second Displaced piston assembly according to braking effect. It is again pointed out that in normal operation, in which the servo pressure circuit works properly, one power transmission from the brake pedal over the force input member and the actuating piston on the piston assemblies not happened. In this case, only the simulator piston the pedal counter-force simulation device displaced.

A Further development of the invention provides that the servo pressure circuit having a separate pressure source. The servo pressure circuit can beside the separate pressure source also a pressure accumulator and a controllable Valve assembly include to improve the response and to balance pressure peaks.

alternative to use a separate pressure source according to the invention but also be provided that the servo pressure circuit with the pressure source of a Hydraulic brake control system is hydraulically connected. there it can be, for example, an anti-lock system, an anti-slip regulation or the like.

Also according to the invention be provided that the first piston assembly with the first cylinder bore a first brake pressure chamber and the second piston assembly with the second cylinder bore includes a second brake pressure chamber, wherein in the first and second brake pressure chamber as a result of a displacement of first and second piston assemblies transferable to the hydraulic brake system Hydraulic pressure is built up.

Furthermore, a further development of the invention provides that the first and second piston arrangements are each biased into a braking effectless starting position. In this context, the braking behavior can be improved be that each piston assembly is associated with a pressure relief valve, which interrupts a connection between the respective pressure chamber and a pressure-relieved reservoir at a displacement of the respective piston assembly from a bremswirkungslosen initial position in the brake effective Auslenkstellung and return from the effective braking deflection position in the starting position with the respective pressure chamber the pressure-relieved reservoir connects. As a result, the pressure in the Radbremseinheiten is degraded faster after completion of the braking process.

Regarding the operation of the braking force generator according to the invention in the above-mentioned several times Normal operating situation in which the servo pressure circuit is working properly and a displacement of the first and second piston assemblies via the Servo pressure circuit is possible and an emergency operation situation in which the servo pressure circuit due leaks or a defect in the pressure source is not working properly, the following should be done. According to the invention is this provided in a preferred embodiment, that in a normal operating situation with functioning servo pressure circuit the first and second piston assembly in accordance with the pedal operation under Use of the servo pressure from the servo pressure circuit can be displaced with braking effect are. With regard to the control of the pedal counterforce simulation device will be in one execution with safety chamber in normal operating situation while operating Servodruckkreis the safety chamber with servo pressure from the servo pressure circuit applied. As a result, a displacement of the separating piston is prevented.

As already mentioned, is in an emergency operating situation when not working properly Servodruckkreis after passing through clearance the first and second Piston arrangement over the actuating piston relocated. Regarding the safety chamber is in the emergency operation situation provided that these are connected to the pressure-neutral reservoir becomes. As a result, the separating piston shifts in consequence of a pedal operation in Essentially without resistance, so the simulation spring, which is supported on the separating piston, as it were mitwandert and not compressed. In the result results also no simulation power, the addition of the driver to additionally deriving from the pressure chambers in the context of braking force generation Overcome counterforce would have to be.

The The invention further relates to a brake force generator of the above executed type described Motor vehicle brake system.

in the Below, the invention will be described by way of example with reference to the accompanying Figures explained. Show it:

1 a schematic overview of a braking force generator according to the invention, as it is integrated in a hydraulic motor vehicle brake system;

2 an enlarged schematic representation of the brake force generator according to the invention 1 ;

3 a second embodiment of the braking force generator according to the invention in one 2 corresponding representation;

4 the in 3 illustrated braking force generator, as he in a too 1 alternatively executed brake power is integrated;

5 a third embodiment of the braking force generator according to the invention in detail;

6 the braking force generator according to 5 , integrated in the motor vehicle brake system according to 4 ;

7 a perspective view of a fourth embodiment of the braking force generator according to the invention and

8th a schematic representation of the arrangement of the first and second piston assembly and simulator piston in the embodiment according to 7 ,

In 1 and 2 an inventive braking force generator is shown schematically and generally with 10 designated, wherein the braking force generator in 1 integrated in a motor vehicle brake system and in 2 is shown in an enlarged schematic representation.

The braking force generator 10 includes a housing 12 , in the three cylinder bores 14 . 16 and 18 are incorporated. The cylinder bore 18 is stepped and has a shoulder acting as a stop 20 on. The cylinder bore 14 takes a first piston assembly 22 on, in the direction of a bore longitudinal axis A within the cylinder bore 14 is relocatable. The cylinder bore 16 takes a second piston assembly 24 in the direction of the bore longitudinal axis B displaced. In the third stepped cylinder bore 18 is a simulator piston 26 a pedal counter force simulation device 52 taken, which is also guided in the direction of the bore longitudinal axis C displaced.

In the first and second cylinder bore 14 and 16 is a cross pin 28 and 30 mounted in a longitudinal recess of the piston assemblies 22 and 24 is guided, as by its non-hatched middle area in 2 shown. The first piston arrangement 22 is via a return spring 32 in contact with the cross section 28 in the in 2 biased starting position shown. Likewise, the second piston assembly 24 via a return spring 34 in contact with the cross section 30 in the in 2 biased starting position shown.

The piston assembly 22 is at her in 4 left end area with a seal 36 provided and thus closes a pressure chamber 38 with the cylinder bore 14 one. Likewise, the piston assembly 24 with a corresponding seal 40 provided and closes a pressure chamber 42 one.

In these in 2 left end portions of the piston assemblies 22 and 24 are valve elements 44 and 46 provided, which have a valve plate and a valve stem. In the in 2 shown starting position are the valve elements 44 and 46 in the open position, thus providing a fluidic connection between the pressure chamber 38 and 42 and a pressure-relieved reservoir line 48 and 50 , The two pressure chambers 38 and 42 are over fluid lines 53 and 55 connected to the hydraulic brake circuit as in 1 shown. The reservoir lines 48 and 50 On the other hand, they run to a pressure-free fluid reservoir 54 ,

Each of the piston arrangements 22 and 24 is with a piston plunger 56 and 58 Mistake. The two piston plungers 56 and 58 stick in 2 to the right from the cylinder borings 14 and 16 out. They are about seals 60 and 62 sealing in a housing wall 64 guided. Furthermore, the piston arrangements 22 and 24 Sealing flanges with corresponding seals 66 and 68 on. The sealing flanges 66 . 68 close with the housing wall 64 Servo pressure chambers 70 and 72 with, via servo pressure lines 74 and 76 with a servo pressure circuit 80 are coupled (see 1 ).

Also the simulator piston 26 is about a seal 82 fluid-tight in the cylinder guide 18 guided. He is by a return spring 84 against a circlip 86 biased. The return spring 84 is supported by a separating piston 88 from the sealing in the larger diameter portion of the stepped cylinder bore 18 is guided. The separating piston 88 is via a return spring 90 against the shoulder 20 biased. The separating piston 88 has in its central area a simulator piston 26 facing rubber-elastic damping cushion 92 which, where appropriate, an impact of the in 2 to the left protruding ram approach of the simulator piston 26 attenuates. The return spring 90 relies on her in 2 left end to the housing 12 from. The from the simulator piston 26 and the separating piston 88 enclosed simulation chamber 94 is via a fluid line 96 via a fluidic damping system that has a throttle 98 and a check valve 100 has, with the reservoir 54 connected. Also the simulator piston 26 has an in 2 to the right from the stepped cylinder bore 18 projecting valve lifter 102 on.

In the housing is also an actuating piston 104 led, which is a force input element 106 receives. The force input element 106 is with a brake pedal 108 coupled. The actuating piston 104 indicates his in 2 lower end of a permanently installed permanent magnet 110 on, with a permanently installed on the housing Hall sensor 112 cooperates for position detection.

A movement of the actuating piston 104 in the case 12 in 2 to the right is over a circlip 114 limited, which determines the initial position shown. The actuating piston 104 gets over the simulator piston 26 and the cooperating with this return spring 84 to the circlip 114 created, while doing the simulator piston 26 also in contact with the circlip 86 located.

In 2 you finally realize that the two piston tappets 56 and 58 in the in 2 shown starting position at a distance of a clearance s to a Stirnflä surface 116 of the actuating piston 104 are arranged. By contrast, lies the end face of the piston plunger 102 of the simulator piston 126 in contact with the face 116 of the actuating piston 104 ,

In 1 you can see that the servo pressure circuit 80 one about a motor 118 driven pump 120 having. This promotes hydraulic fluid from the reservoir 54 in a fluid line 122 , The fluid line 122 contains a branch with a pressure relief valve 124 , The servo pressure circuit 80 also has a pressure accumulator 126 on, by driving a two-way valve 128 with pressurized fluid from the pump 120 can be loaded. For controlling the two-way valve 128 is a pressure sensor 130 provided with an electronic control unit 132 is coupled. Furthermore, with the electronic control unit 132 another two-way valve 134 for supplying servo pressure fluid via the conduit 76 to the servo pressure chambers 70 and 72 intended. Another two-way valve 136 is for pressure relief of the fluid line 76 via the electronic control unit 132 controllable.

The hydraulic brake system that over the pressure lines 53 and 55 coming from the pressure chambers 38 and 40 can be loaded with pressurized fluid as a result of a brake operation comprises a Radschlupfriegeleinrichtung 138 equipped with wheel brake units 140 . 142 . 144 and 146 works together effectively. The two pressure lines 53 and 55 are each with pressure sensors 148 and 150 Mistake.

How to be both in 1 as well as in 2 detects, is the braking force generator 10 formed relatively compact according to the invention. This is achieved by the cylinder bores 14 . 16 and 18 in the case 12 are arranged side by side and that their longitudinal axes A, B and C are substantially parallel to each other.

During normal operation, ie when the servo pressure circuit is working correctly, the brake pedal is activated 108 actuated. Then the force input element becomes 106 in a corresponding manner in the housing 12 shifted into it. This becomes with the shifting permanent magnet 110 over the position sensor 112 recorded and sent to the electronic control unit 132 reported. The electronic control unit 132 accordingly controls the servo pressure circuit 80 at. This means that via the two-way valve 134 and the fluid line 76 Pressurized fluid in the servo pressure chambers 70 and 72 is directed. Then the piston plumbing becomes 22 and 24 in the cylinder bores 14 and 16 in 2 shifted to the left. As a result of this shift, the valve elements lift 44 and 46 from the cross pins 28 and 30 off and close. Then there is a pressure build-up in the pressure chambers 38 and 42 , The pressurized brake fluid passes over the fluid lines 53 and 55 in the usual way via a wheel slip control device 138 to the wheel brake units 140 . 142 . 144 and 146 passed, so that there is a braking effect.

You return to 2 , it should be noted that the displacement of the actuating piston 104 due to the pedal operation only on the simulator piston 26 is transmitted. By loading the servo pressure chambers 70 and 72 with servo pressure fluid, as described above, the two piston assemblies 22 and 24 in 2 shifted to the left. The gap s is therefore substantially maintained. At the brake pedal 108 the driver only feels that of the pedal simulation device 52 originating simulated pedal drag. It should be noted that the servo pressure via the fluid line 76 also in one of the separating piston 88 with the housing 12 enclosed security chamber 152 is directed. Due to the relatively high servo pressure, the separating piston remains 88 Therefore, in spite of the force acting on the pedal operation in position on the stop 20 , The simulation spring 84 is due to the displacement of the simulator piston 26 however compressed. Further, in the simulation chamber 94 contained hydraulic fluid via the fluid line 96 through the throttle 98 in the fluid reservoir 54 pressed. The resulting resistances are on the pedal 108 as an opposing force noticeable.

When the brake pedal is released 108 the actuating piston moves 104 due to the spring bias of the return spring 84 in his in 2 shown starting position back. This backward movement is again via the position sensor 112 and the moving permanent magnet 110 recorded and sent to the electronic control unit 132 reported. This reduces according to the servo pressure to the braking effect on the wheel brake 140 to 146 to reduce.

In an emergency operating situation in which the servo pressure circuit 80 not working properly, for example because the pump 120 or whose control has failed, the piston arrangements 22 and 24 for lack of servo printing, can not be moved over the servo pressure circuit. To be able to decelerate the vehicle nevertheless, the piston arrangements 22 and 24 after passing through the clearance s mechanically via the actuating piston 104 be relocated. Due to the fact that a servo pressure support is omitted, the safety chamber remains 152 pressure-free, so that the separating piston 88 contrary to the relatively low restoring force of the return spring 90 in 2 can shift to the left. When a pedal operation is therefore the simulator piston 26 in 2 moved to the left, with the relatively stiff simulation spring 84 remains largely uncompressed. On the other hand gives the separating piston 88 in 2 to the left. A shift of the simulator piston 26 therefore initially takes place without resistance until the clearance s is closed. Then the face goes down 116 to the facing these faces of the piston plunger 56 and 58 at. As a result of a further shift, the piston arrangements 22 and 24 in 2 directly shifted mechanically by the pedal operation to the left, whereupon results in a mechanically generated braking effect.

According to the invention, the servo-pressure-assisted normal braking operation and the actuation of the piston arrangements can be achieved 22 and 24 perform on the brake pedal in the same way, as in the prior art, just by a considerably compact designed braking force generator, in which the cylinder bores 14 . 16 . 18 lying side by side in a plane with parallel bore longitudinal axes A, B and C are arranged.

The following is to the second Ausfüh according to 3 and 4 To be received. For convenience of description and avoidance of repetition, the same reference numerals as in the description of the first embodiment will be given for equivalent components 1 and 2 used, but with the small letter "a" readjusted.

The embodiment according to 3 of the braking force generator 10a differs from the braking force generator 10 according to 2 only in that the pedal simulation device without separating piston 88 is executed. Rather, the return spring 84a runs longer and rests on the bottom of the 3 non-stepped cylinder bore 18a from.

However, the involvement of the braking force generator differs 10a in the brake system considerably from the embodiment according to 1 , Unlike the embodiment according to 1 in which over the two fluid lines 53 and 55 all four wheel brake units 140 am 146 be supplied with hydraulic fluid and at the a separate pressure source for the servo pressure circuit 80 is provided, via the fluid lines 53a and 55a in the embodiment according to 4 only the two wheel brake units assigned to the front wheels 140a and 142a directly charged with Hydralikfluid, which from the fluid reservoir 54a is removable.

The servo chambers 70a and 72a be from hydraulic pumps 160a and 162a and via an intermediate electromagnetic control valve 164a fed. Furthermore, via the fluid line 96a entering the simulation chamber 194a opens, a counter-force generating device 166a provided, which also has a throttle 98a with the simulation chamber 94a communicated.

One recognizes in 4 that hydraulic fluid from the pumps 160a and 162a via the electromagnetic control valve 164a in the fluid line 168a can be directed. From this fluid line 168a can be controlled by controlling the control valves 170a and 172a the two wheel brake units associated with the rear wheels 144a and 146a feed with hydraulic fluid. It can also be opened by opening the control valves 174a and 176a such as 178a and 180a Servo fluid in the servo pressure lines 74a and 76a initiate or derive from these. The two control valves 182a and 186a serve for pressure relief of the two wheel brake units 144a and 146a ,

A control valve 188a serves for pressure relief of the simulation chamber 94a , A control valve 190a serves to connect between the wheel brake units 144a and 146a to the reservoir 54a provide. A control valve 192a serves the counterforce of the counter-force generating device 166a with the fluid reservoir 54a connect and provide for a pressure relief.

Throughout the system are a plurality of pressure sensors 194a . 196a . 198a and 200a each provided for pressure monitoring and allow control of the brake system in accordance with the detected pressure values. The pressure sensor 194a serves to control a charge of the pressure accumulator 126a , The pressure sensor 196a serves to detect the pressure in the simulator chamber 94a , The pressure sensor 198a serves to detect the pressure for loading the wheel brake units 144a and 146a , which is used as a servo print. The pressure sensor 200a serves to control the valve 190a for the purpose of relieving the wheel brake units 144a and 146a ,

The functioning of the braking force generator 10a according to 4 essentially corresponds to the operation of the braking force generator 10 according to 2 , In an emergency operating situation, however, the simulation chamber 94a over the valve 180a with the fluid reservoir 54a connected, so that a pressure relief can take place. All that remains then is the resistance of the simulation spring 84a be overcome.

Hereinafter, the third embodiment will be described with reference to FIG 5 and 6 explained. Again, only the differences from the previous embodiments will be described, with the same reference numerals, but followed by the lower case letter "b", used for equivalent components.

The braking force generator 10b according to 5 and 6 differs from the braking force generator 10a according to 3 in that the pedal counterforce simulation device 52b in the middle between the two cylinder bores 14b and 16b is arranged, which the piston arrangements 22b and 24b take up. The two piston plungers 56b and 58b are in turn at a distance s from the coming into contact with this end face of the actuating piston 104b arranged, whereas the piston plunger 102b of the simulator piston 26b on the actuating piston 104b is applied. The end faces, with the piston tappets 22b . 24b and 102b cooperate, are in corresponding openings in the actuating piston 104b intended. The three bore longitudinal axes A, B and C are parallel to each other and lie in one plane. The housing 12b is formed in two parts and has at its in 5 right area a housing cover 202b on. In this case cover 202b a central opening is provided in which the actuating piston 104b over his piston shaft 204b guided displaceable along the longitudinal axis C.

The return springs 32b and 34b the piston arrangements 22b and 24b are not in the pressure chambers 38b attached, but in the pressure-neutral area in front of it. They are supported by a diameter step around the housing 12b from. For sealing guidance of the piston plunger 56b and 58b are guide bushes 206b and 208b in the case 12b appropriate.

The special feature of the braking force generator 10b according to 5 lies in the fact that the braking forces on the force input member coaxial with the actuating piston 104b be introduced and that these then coaxial with the simulator piston 26b be transmitted. As a result, lateral forces and tilting moments can be prevented.

The integration of the braking force generator 10b according to 5 in the motor vehicle brake system takes place in the same manner as with reference to 4 for the second embodiment and the local braking force generator 10a described.

7 and 8th show a fourth embodiment of the invention. Again, the same reference numerals are used for equivalent components as in the description of the first three embodiments, but with the lowercase letter "c" readjusted.

In 7 you can see that through the three piston tappets 56c . 58c and 102c Although in the longitudinal direction extending longitudinal axes A, B and C are parallel to each other, but in contrast to the first three embodiments are not in a plane. Rather, the piston tappets 56c . 58c and 102c in the case 12c of the braking force generator 10c arranged so that they, as in 8th shown with their lying on the longitudinal axes A, B, C centers on a virtual circle 210c lie and span a dotted equilateral triangle. As a result, the entire arrangement can be made more compact. In particular, with the piston tappets 56c . 58c and 102c in the various operating situations coming into contact face of the actuating piston (in 7 and 8th not shown) with the smallest possible diameter.

7 shows an extremely compact designed braking force generator 10c whose operation corresponds to the embodiments described above.

Claims (25)

Brake force generator ( 10 ) for a hydraulic motor vehicle brake system with - a housing ( 12 ), - two piston arrangements ( 22 . 24 ), wherein a first piston arrangement ( 22 ) in a first cylinder bore ( 14 ) of the housing ( 12 ) is received displaceably along a first bore longitudinal axis (A) and wherein a second piston arrangement ( 24 ) in a second cylinder bore ( 16 ) is displaceably received along a second bore longitudinal axis (B), - a counterforce force simulation device ( 52 ) - and a force input element ( 106 ) with a brake pedal ( 108 ) is coupled or coupled, wherein upon movement of the force input element ( 106 ) the pedal counter-force simulation device ( 52 ) and wherein in accordance with the movement of the force input member ( 106 ) the first and the second piston arrangement ( 22 . 24 ) are displaceable, characterized in that the counterforce force simulation device ( 52 ) a simulator piston ( 26 ), which in a third cylinder bore ( 18 ) of the housing ( 12 ) along a third bore longitudinal axis (C) is received displaceably, wherein the first, second and third cylinder bore (C) ( 14 . 16 . 18 ) in the housing ( 12 ) are arranged side by side. Brake force generator ( 10 ) according to claim 1, characterized in that the first, second and third bore longitudinal axis (A, B, C) are substantially parallel to each other. Brake force generator ( 10 ) according to claim 2, characterized in that the first, second and third bore longitudinal axis (A, B, C) lie substantially in one plane. Brake force generator ( 10 ) according to claim 3, characterized in that the first cylinder bore ( 14 ) with the first piston arrangement ( 22 ) and the second cylinder bore ( 16 ) with the second piston arrangement ( 24 ) are arranged adjacent to each other and that the third cylinder bore ( 18 ) with the simulator piston ( 26 ) next to the pair of cylinder bores ( 14 . 16 ) is arranged. Brake force generator ( 10b ) according to claim 3, characterized in that the third cylinder bore ( 18b ) with the simulator piston ( 26b ) between the first cylinder bore ( 14b ) with the first piston arrangement ( 22b ) and the second cylinder bore ( 16b ) with the second piston arrangement ( 24b ) is arranged. Brake force generator ( 10 ) according to claim 2, characterized in that the first, second and third bore longitudinal axis (A, B, C) viewed in an axis orthogonal section ( 8th ) form the corners of a triangle, preferably an isosceles triangle, in particular an equilateral triangle. Brake force generator ( 10 ) according to one of the preceding claims, characterized in that with the force input member ( 106 ) in the housing ( 12 ) guided actuating piston ( 104 ), wherein the actuating piston ( 104 ) an actuating end face ( 116 ) cut by each of the piston longitudinal axes (A, B, C). Brake force generator ( 10 ) according to claim 7, characterized in that the actuating piston ( 104 ) is dimensioned such that it faces in an axis-orthogonal projection surface facing the first and second piston arrangement ( 22 . 24 ) and the simulator piston ( 16 ) encloses. Brake force generator ( 10 ) according to one of the preceding claims, characterized by a position detection device ( 110 . 112 ) for detecting the current operating position of the force input element ( 106 ). Brake force generator ( 10 ) according to claim 8 and 9, characterized in that the position detecting means a on the actuating piston ( 104 ) mounted movable component ( 110 ) and one on the housing ( 12 ) arranged stationary component ( 112 ) having. Brake force generator ( 10 ) according to one of claims 7 to 10, characterized in that the first piston arrangement ( 22 ) and the second piston assembly ( 24 ) as well as the simulator piston ( 26 ) each one to the actuating piston ( 104 ) in the direction of the respective bore longitudinal axis (A, B, C) projecting piston plunger ( 56 . 58 . 102 ), wherein the actuating piston ( 104 ) in the actuation case at least on the piston plunger ( 102 ) of the simulator piston ( 26 ) in order to open this in the third cylinder bore ( 18 ) to move. Brake force generator ( 10 ) according to claim 11, characterized in that in an initial position of the piston tappet ( 102 ) of the simulator piston ( 26 ) with its end face on the actuating piston ( 104 ) and that a clearance (s) between the piston tappets ( 56 . 58 ) of the first and second piston assemblies ( 22 . 24 ) and the actuating piston ( 104 ) is provided. Brake force generator ( 10 ) according to one of claims 7 to 12, characterized in that the simulator piston ( 26 ) with a simulation spring ( 84 ) on the actuating piston ( 104 ) is too tense. Brake force generator ( 10 ) according to claim 13, characterized in that in the third cylinder bore ( 18 ) a separating piston ( 88 ) provided with a biasing spring ( 90 ) towards the simulator piston ( 26 ) against a stop ( 20 ) is biased, wherein the simulation spring ( 84 ) on the separating piston ( 88 ) is supported, wherein the separating piston ( 88 ) one of the simulator piston ( 26 ) completed simulation chamber ( 94 ) of a safety chamber ( 152 ) separates. Brake force generator ( 10 ) according to one of the preceding claims, characterized in that the first and second piston arrangements ( 22 . 24 ) by means of a servo pressure circuit ( 80 ) is effective for braking. Brake force generator ( 10 ) according to claim 15, characterized in that the servo pressure circuit ( 80 ) a separate pressure source ( 120 ) having. Brake force generator ( 10 ) according to claim 15, characterized in that the servo pressure circuit ( 80a ) with the pressure source ( 160a . 162a ) of a hydraulic brake control system is hydraulically connectable. Brake force generator ( 10 ) according to one of the preceding claims, characterized in that the first piston arrangement ( 22 ) with the first cylinder bore ( 14 ) a first brake pressure chamber ( 38 ) and the second piston assembly ( 24 ) with the second cylinder bore ( 16 ) a second brake pressure chamber ( 42 ), wherein in the first and second brake pressure chamber ( 38 . 42 ) as a result of a displacement of the first and second piston arrangements ( 22 . 24 ) is constructed in the hydraulic brake system transferable hydraulic pressure. Brake force generator ( 10 ) according to one of the preceding claims, characterized in that the first and second piston arrangements ( 22 . 24 ) are each biased in a bremswirkungslose starting position. Brake force generator ( 10 ) according to claim 19, characterized in that each piston assembly ( 22 . 24 ) a pressure relief valve ( 44 . 46 ) associated with a displacement of the respective piston assembly ( 22 . 24 ) from a bremswirkungslosen initial position in the brake effective deflection position a connection between the respective pressure chamber ( 38 . 42 ) and a depressurized reservoir ( 54 ) interrupts and on return from the effective braking deflection position in the starting position, the respective pressure chamber ( 38 . 42 ) with the pressure-relieved reservoir ( 54 ) connects. Brake force generator ( 10 ) according to any one of claims 15 to 20, characterized in that in a normal operating situation with functioning servo pressure circuit, the first and second piston arrangement ( 22 . 24 ) in accordance with the pedal operation using the servo pressure from the servo pressure circuit ( 80 ) are effectively displaced by braking. Brake force generator ( 10 ) according to claim 14 and 21, characterized in that in the normal operating situation with functioning servo-pressure circuit ( 80 ) the safety chamber ( 152 ) with servo pressure from the servo pressure circuit ( 80 ) can be acted upon. Brake force generator ( 10 ) according to one of claims 15 to 22, characterized in that in an emergency operating situation with not properly functioning servo pressure circuit ( 80 ) the first and second piston assemblies ( 22 . 24 ) via the actuating piston ( 104 ) are relocatable. Brake force generator ( 10 ) according to one of claims 15 to 23, characterized in that in the emergency operating situation with not properly functioning servo pressure circuit ( 80 ) the safety chamber ( 152 ) with the pressure-neutral reservoir ( 52 ) connected is. Hydraulic motor vehicle brake system with a braking force generator ( 10 ) according to one of the preceding claims.