DE3936180A1 - Traction slip controller for road vehicle with antilock braking - has additional master cylinder acted upon by vacuum in larger cylinder with piston position monitor switch - Google Patents

Abstract

The vehicle has a hydraulic two-wheel braking circuit (10) with a drive motor (11), ABS system (12) and a traction slip controller (13). The braking circuit for one or more driven wheels includes an additional master cylinder (63) whose piston is positioned by a pneumatic or hydraulic cylinder (64) connected by a valve to the auxiliary power source of the braking force amplifier. The piston of this cylinder (64) has a projecting rod with a radial enlargement which at about one-fifth to one-third of max. travel operates a rocker switch (99). An electronic control unit (50) receives signals from electronic wheel-speed sensors (51-54) and a braking light switch (49) to produce control signals for brake pressure control valves (31-34) and a drive motor (47) of return feed pumps (28, 29). ADVANTAGE - Gives faster and more sensitive application in combination with any type of antilock braking system having individual wheel brake pressure control valves.

Description

The invention relates to a drive slip control device (ASR) for an also with an anti-lock braking system (ABS) equipped road vehicle with hydraulic multi-circuit braking system and with the others, in the preamble of Claim 1, generic features.

Such an ASR is known from DE 38 02 132 A1.

This works with the well-known ASR combined with an ABS ABS according to the return conveyor principle, the ASR according to the principle propelled vehicle wheel that tends to spin Delay activation of his wheel brake again. The wheel brakes individually assigned brake pressure control valves, by means of which  Brake pressure build-up, brake pressure maintenance and brake pressure reduction phases are controllable for both the ABS and the ASR exploited analogously. As an auxiliary pressure source for the ASR, the is designed for a vehicle with rear axle drive the return pump of the brake circuit of the driven Vehicle wheels exploited. For feeding the return pump a precharge pump provided the brake fluid from the Feeds the brake device reservoir to the return pump.

One disadvantage of the known ASR is that it is very difficult powerful precharge pump is required, the substantial Installation space required. Another disadvantage is that the ASR - because the limited flow rates per stroke of the usual Return pumps - "slow" responds. Can be disadvantageous also be considered that the ASR has a special design of the ABS, namely as working on the return principle, assumes.

The object of the invention is therefore an ASR of the beginning to improve the type mentioned in that this at nevertheless simple construction a faster - more sensitive - Responsiveness enables and also more universal, d. i.e., in Combination with any type of anti-lock braking system can be used in which the vehicle wheels individually assigned Brake pressure control valves are provided.

This object is achieved by the characterizing Part of claim 1 mentioned features solved.

This is for the brake circuit of the driven vehicle wheels an additional master cylinder is provided, which as Drive element for its piston one according to the structure  Drive element of the brake booster of the braking device Brake system corresponding, pneumatic or hydraulic The drive cylinder has a valve-controlled connection its working chamber (s) to the - hydraulic or pneumatic - Auxiliary power source that also the brake booster of the Brake device supplied, in the sense of a brake pressure build-up for the traction control system can be acted upon.

The resulting benefits are at least the following: the additional master cylinder is including his Drive cylinder in broad analogy to one conventional master cylinder with brake booster very simple and inexpensive to implement because it does not have its own brake valve or other actuators required and overall is much cheaper than a pre-charge pump.

The response behavior of the ASR according to the invention is essential faster - more sensitive - than when using a return pump as an auxiliary pressure source with limited delivery stroke.

The ASR is like an "additional device" to a large number common anti-lock braking systems can be implemented. There is also the fact that if the ASR responds, as the brake circuit of the driven vehicle wheels assigned return pump of the ABS if brake fluid is in brake pressure reduction phases - in the additional master cylinder - feeds back, not must work against pressure, noise problems against one ASR, where the return pump is used as an auxiliary pressure source is significantly lower, so that the ASR according to the invention driving comfort less impaired than the known ASR.  

The for the operation of the additional master cylinder required auxiliary energy can either by means of a Vacuum brake booster similar pneumatic Drive cylinder - using the vacuum on Intake manifold of a naturally aspirated engine - or by means of one on the Pressure level of a power steering or a level control designed hydraulic pressure translator can be obtained.

The ASR according to the invention is also in a simple manner Claim 2 can be used in a vehicle with all-wheel drive.

Due to the features of claims 3 and 4 are different Designs of a pressure supply control valve specified, via which when the ASR brake pressure responds to the Wheel brake (s) of a brake circuit of driven vehicle wheels can be coupled. These designs are with vehicles All-wheel drive can also be used in combination.

Due to the features of claim 5 is a first Operating possibility of the ASR according to the invention provided auxiliary pressure source, which, when using a pneumatic drive cylinder for the additional Master cylinder alternatively by the features of claims 6 and 7 is easy to implement and use a hydraulic drive cylinder according to the features of Claim 8 can be realized.

The operating mode provided according to claim 9 within the scope of ASR provided auxiliary pressure source results in an even faster Response behavior of the traction control system, required but monitoring the position of the piston Additional master cylinder drive cylinder to  ensure that this is always sufficient Brake fluid volume contains and not through leakage can be exhausted.

When using pneumatic drive cylinders for the additional master cylinders are characterized by the features of the claims 10 and 11 alternative implementation options of the ASR specified.

In the principal by the features of claim 12 Design and function according to outlined, by the characteristics of claim 13 specified in more detail and according to the features of claims 14 to 16 in details of alternative realizable, preferred embodiments of the ASR according to the invention this becomes a brake pressure development also in normal braking operation exploited on the rear axle of the vehicle, in that an increased in the partial braking area Rear axle braking force share corresponding braking force distribution is achieved by - with a given actuation force - increased values of the braking deceleration are achievable and the Brake system overall with a better approach to one ideal braking force distribution can be operated than this one to a "stable" fixed brake force distribution designed master cylinder is possible.

Here, in particular, is the embodiment according to claim 16 distinguished by a sensitive response behavior of the ASR.

Further details and features of the invention emerge more specific from the description below Exemplary embodiments with reference to the drawing. Show it:  

Fig. 1 is a hydraulic diagram of a first embodiment of the ASR according to the invention with a pressure supply control valve designed as a solenoid valve and auxiliary pressure source kept permanently at a high output pressure level

FIG. 2 shows a longitudinal section of a single-circuit master cylinder with a pneumatic drive cylinder that can be used in the context of the auxiliary pressure source of the ASR according to FIG. 1

Fig. 3 is a longitudinal sectional view of a frame in the ASR of FIG. 1 can be used single-circuit master cylinder with hydraulic drive cylinder

Fig. 4 shows an embodiment with a pressure-controlled pressure supply control valve of the ASR

Figure 5 is a suitable for a vehicle with all-wheel drive configuration of the ASR.

Fig. 6a shows an embodiment of the ASR according to the invention, which can be used for generating brake pressure in the rear axle brake circuit and

Fig. 6b, a further embodiment with the brake force generating in the normal braking mode-utilized ASR by holding at a high output pressure level of the auxiliary pressure source.

In Fig. 1, to the details of which reference should first be made, a road vehicle is represented by a hydraulic dual-circuit braking system, designated overall by 10 , and a drive motor 11 , which is only indicated schematically, and which is equipped with an anti-lock braking system designated overall by 12 ( ABS) as well as a drive-slip control device (ASR), designated in total by 13 .

For the vehicle it is - initially - assumed that it has a rear axle drive, and that in the context of the brake system 10, the wheel brakes 14 and 16 of the - non-driven - front wheels form a brake circuit I and the wheel brakes 17 and 18 of the - driven - rear wheels are combined to form a brake circuit II.

The two brake circuits I and II are designed as static brake circuits, for the brake pressure supply of which a tandem master cylinder 22 , which can be actuated by means of a brake pedal 19 via a brake booster 21 , is provided, which is known per se, and which has two, each one of the two brake circuits I and II has assigned output pressure spaces, to the pressure outputs 23 and 24 of which the main brake lines 26 and 27 of the front axle brake circuit I and the rear axle brake circuit II are connected, which branch off at the branching points 28 and 29 into the front wheel brakes 14 and 16 and branch the rear wheel brakes 17 and 18 further brake line branches 26 'and 26 "or 27 ' and 27 ".

For the ABS 12 , in the special embodiment shown, an implementation according to the so-called return principle is required, according to which, in the brake pressure reduction phases of the anti-lock control, a front wheel brake 14 or 16 and / or a rear wheel brake 17 or 18, respectively, which is subject to the regulation drained brake fluid is pumped back by means of a return pump 28 assigned to the front axle brake circuit I or a return pump 29 assigned to the rear axle brake circuit II into the output pressure space of the tandem master cylinder 22 assigned to the front axle brake circuit I or the rear axle brake circuit II.

As part of the ABS 12 , the front wheel brakes 14 and 16 and the rear wheel brakes 17 and 18 are individually assigned brake pressure control valves 31 and 32 or 33 and 34 , which are designed as solenoid valves and which, in the special embodiment shown, are 3/3-way Valves are formed.

The - in the non-energized state of their control magnets 36 - basic position 0 of these brake pressure control valves 31 to 34 is a flow position in which the (the) wheel brake cylinder 14 'and / or 16 ' of the front brakes 14 and 16 and the wheel brake cylinders 17 'and / or 18 'of the rear wheel brakes 17 and 18 communicating with the branch point 28 and 29 of the main brake line 26 and 27 of the front and rear axle brake circuit I or II communicating and thus to the pressure output 23 or 24 of the tandem master cylinder 22 are connected.

This basic position 0 of the brake pressure control valves 31 to 34 is both the normal, that is, braking operation not subject to an anti-lock control - and a brake operation subject to an anti-lock control - brake pressure reconstruction phases of the anti-lock control - in each case on the wheel brake 14 and / or 16 or 17 and / or 18 subjected to the control.

By excitation of the control magnets 36 with a control current defined current of z. B. 3 A, the brake pressure control valves 31 to 34 , individually, several or together in a first excited position I can be switched, the same as part of the anti-lock control brake pressure holding phases on the respectively connected wheel brakes 14 and / or 16 or 17 and / or 18 is assigned.

By energizing the control magnets 36 of the brake pressure control valves with a control current defined, higher amperage, for. B. a current of 6 A, the brake pressure control valves 31 to 34 , individually, several or together in an alternate to the excited position I alternate position II are switchable, the brake pressure reduction phases on the respective wheel brake 14 and / or 16th or 17 and / or 18 is assigned. In this brake pressure reduction position of the respective brake pressure control valve, the front wheel brake 14 and / or 16 or rear wheel brake 17 , which can be connected via this to the main brake line 26 or 27 of the front axle brake circuit I or the rear axle brake circuit II or can be locked against it and / or 18 connected to a return line 36 of the front axle brake circuit I or a return line 37 of the rear axle brake circuit II, but at the same time against the respective branch 26 'or 26 "of the main brake line 26 of the front axle brake circuit I or the brake line branch 27 ' or 27 ″ of the main brake line 27 of the rear axle brake circuit II blocked.

The return pump 28 of the front axle brake circuit I and the return pump 29 of the rear axle brake circuit II are connected to these return lines 36 and 37 via an input check valve 38 and 39, respectively, which in the brake pressure reduction phases of the anti-lock control Brake fluid drained from a wheel brake subject to the control via its respective output check valves 41 and 42 into the main brake line 26 of the front axle brake circuit I or the main brake line 27 of the rear axle brake circuit II and thus into the output pressure spaces of the tandem assigned to these brake circuits I and II - Feed back the main cylinder 22 .

To the return lines 36 and 37 , a low-pressure buffer store 43 or 44 , usually designed as a piston-spring accumulator, is connected, which can "quickly" absorb brake fluid drained from a wheel brake of the respective brake circuit, which can then be removed by means of the return pump (n ) 28 and / or 29 is successively pumped back into the tandem master cylinder 22 . The buffer stores 43 and 44 enable rapid brake pressure reduction in the connected wheel brakes 14 and 16 or 17 and 18 and the use of return pumps 28 and 29 , which are designed as piston pumps, with a relatively small stroke volume, which is about 1/10 of the Recording volume of the respective memory 43 or 44 is.

The return pumps, which are usually designed as free-piston pumps, have, as only shown schematically, a common eccentric drive, which in turn can be driven by means of an electric motor 47 .

To the brake pressure control valves 31 to 34 each individually connected check valves 48 , which by relatively higher pressure in the respective wheel brake cylinder 14 'and 16 ' or 17 'and 18 ' of the front axle brake circuit I or the rear axle brake circuit II than in each assigned output pressure chamber of the tandem master cylinder 22 in the opening direction are provided for the purpose of being able to lower the brake pressure even if one or more of the brake pressure control valves 31 to 34 should "hang" in its blocking position I due to malfunction.

The ABS 12 , which has been explained on the basis of its hydraulic and electrohydraulic components, can be assumed to be known in terms of its structure and function, the control signals from an electronic control unit 50 being required for the control-appropriate control of the brake pressure control valves 31 to 34 and the drive motor 47 of the return pumps 28 and 29 from processing carried out according to known criteria from the information about the dynamic behavior of the vehicle wheels - wheel circumference speed and acceleration - containing output signals to the vehicle wheels of individually assigned electronic wheel speed sensors 51 to 54 and the brake light switch 49 of the brake system 10 .

An explanation of the electronic control unit 50 that goes into the details of the control and circuitry is therefore not considered necessary.

For the traction control system (ASR) 13 it is presupposed that it works according to the principle known per se, to retard a propelled vehicle wheel that tends to spin by activating its wheel brake (s) 17 and / or 18 to the extent that its traction slip is kept within a value range which is compatible both with good driving stability and with good acceleration of propulsion, the dynamic state of the driven vehicle wheels in turn being recorded from processing of the output signals of the wheel speed sensors based on known criteria.

The ASR 13 comprises an auxiliary pressure source, designated overall by 56 , which is activated when the traction-slip control responds in order to generate a pressure which can be coupled into the brake circuit II of the driven vehicle wheels as brake pressure and which is at the required - high - pressure level at a pressure outlet 57 the auxiliary pressure source 56 is provided, and a pressure supply control valve 58 , via which the output pressure of the auxiliary pressure source 56 can be coupled into the brake circuit II of the driven vehicle wheels.

In the special embodiment shown in FIG. 1, the pressure supply control valve is designed as a 3/3-way solenoid valve, the basic position 0 of which is its flow position, in which the pressure output 24 of the tandem assigned to the brake circuit II of the driven vehicle wheels. Master cylinder 22 is connected via a flow path 59 of the pressure supply control valve 58 to the section 27 ′ ″ of the main brake line 27 of the rear axle brake circuit II which leads to the branching point 29 of the rear axle brake circuit II, this section 27 ′ ″ of the main brake line 27 of the rear axle -Brake circuit II, however, is blocked against the pressure outlet 57 of the auxiliary pressure source 56 . This basic position 0 of the pressure supply control valve 58 is assigned to the normal as well as to the braking operation subject to an anti-lock control.

By energizing the control magnet 61 of the pressure supply control valve 58 with a control current defined, relatively low current of z. B. 3 A, the pressure supply control valve 58 is controllable in a first excited position I, a blocking position in which both the rear axle brake circuit II associated pressure outlet 24 of the tandem master cylinder 22 and the pressure outlet 57 of the auxiliary pressure source 56 against that of the Pressure supply control valve 58 to the branch point 29 of the rear axle brake circuit II leading section 27 '″ of the main brake line 27 of the rear axle brake circuit II are blocked.

By excitation of the control magnet 61 of the pressure supply control valve 59 with a control current defined, higher control current of z. B. 6 A, the pressure supply control valve 58 is controllable in a second excited position II, in which the pressure outlet 57 of the auxiliary pressure source 56 via a second flow path 62 of the pressure supply control valve 58 to the branching point 29 of the rear axle brake circuit II Section 27 '″ of the main brake line 27 connected, this section 27 ' ″, however, is blocked off from the main brake line 27 of the rear axle brake circuit II leading to the pressure supply control valve 58 .

This - excited - functional position II of the pressure supply control valve 58 is assigned to the brake pressure build-up operation of the traction control system.

To explain a typical control game of a drive-slip control achievable with the drive-slip control device 13 , for the realization of which the brake pressure control valves 33 and 34 assigned to the driven vehicle wheels and the wheel speed sensors 51 to 54 of the ABS 12 are also used assumed that the left rear wheel tends to spin, which z. B. on the basis of the output signals of the wheel speed sensors 53 and 54 assigned to the driven rear wheels, it can be seen that the wheel peripheral speed of the left rear wheel is significantly greater than that of the right rear wheel and / or a value determined by time differentiation of the output signal of the wheel speed sensor 51 assigned to the left rear wheel the wheel circumference acceleration corresponds to an "unphysically" excessive value and / or can be recognized from a comparison of the wheel circumference speeds of the driven rear wheels with those of the non-driven front wheels.

With the onset of such a spinning tendency, expediently before a pressurization of the brake 17 of the spinning wheel becomes necessary, that is to say preparatory, the auxiliary pressure source 56 is activated and the pressure supply control valve 58 and the brake pressure control valve 34 of the spinning tendency Rear wheel switched into their locking positions I, while the brake pressure control valve 33 of the rear wheel, which tends to spin, remains in its basic position 0. As a result, the driven vehicle wheel to be subjected to the regulation is “selected” and the traction control system 13 is prepared for the brake intervention, as it were. As soon as this is required, the pressure supply control valve 58 is controlled in its flow position II connecting the pressure outlet 57 of the auxiliary pressure source 56 with the main brake line section 27 ′ ″, in which now the brake pressure control valve 33, which is in its basic position 0, tends to spin Vehicle wheel brake pressure is coupled into its wheel brake 17 . It sounds like the spinning tendency of the left rear wheel, recognizable z. B. the fact that its acceleration decreases, the brake pressure control valve 33 of this wheel brake is switched to its blocking position I, whereby the brake pressure applied to the wheel brake 17 remains at the previously reached value. If this brake pressure is subsequently insufficient to bring the vehicle wheel, which tends to spin, back to a value range of its drive slip that is compatible with stable dynamic behavior, the brake pressure control valve 33 is switched back to its basic position 0 in order to further increase the brake pressure. If the spinning tendency then subsides again, the brake pressure control valve 33 is switched into its blocking position I again and, if the brake pressure coupled into the wheel brake 17 of the rear wheel which tends to spin, is sufficient to decelerate this rear wheel sufficiently, the brake pressure control valve 33 finally switched to its energized position II, its pressure reduction position, in which now, in analogy to a brake pressure reduction phase of the anti-lock control, the means provided for this purpose - buffer store 44 and return pump 29 of the rear axle brake circuit II for realizing the drive slip. Control brake pressure reduction phase to be exploited.

It is understood that a vehicle wheel driven on the other required drive slip control cycle and / or one common traction control system on both driven Vehicle wheels can be controlled in an analog manner.

The control signals required for the drive slip control for the activation of the auxiliary pressure source 56 , the control-appropriate control of the pressure supply control valve 58 and the brake pressure control valves 33 and 34 of the brake circuit II of the driven vehicle wheels are also based on criteria known per se processing of the output signals of the wheel speed sensors 51 to 54 is generated by the electronic control unit 50 , the configuration of which is necessary in this regard and which is suitable for realizing the drive slip control function, making it possible for the person skilled in the art of electronic circuit technology, with knowledge of the purpose, to use the usual means available to him is, so that the explanation of electronic circuitry details of the electronic control unit 50 does not appear to be necessary.

In the special exemplary embodiment shown in FIG. 1, the auxiliary pressure source 56 comprises, as a brake pressure generating element, a "single-circuit" master cylinder 63 , which is shown in its basic structure according to FIG. 2, to the details of which reference is also made, and which is operated by means of a pneumatic Drive cylinder 64 is actuated.

The single-circuit master cylinder 63 comprises in a known by itself arrangement and design of a slidable in a bore 66 of its housing 67, pistons, generally designated 68, which comprises two connected by a piston rod 69 with each other, each individually against the housing bore 66 sealed piston flanges 71 and 72 , the axial distance of which determines the axial extent of a trailing space 73 , which is arranged in the radial direction via a longitudinal slot in the piston rod 69 , which is provided with outlet bores 74 and extends through the housing through a longitudinal slot, which extends between the flanges 71 and 72 of the piston 68 stop tube 76 passing therethrough is in communication with the brake fluid reservoir 77 of the master cylinder 22 of the brake system 10 . The one, as shown in FIG. 2, left piston flange 71 of the master cylinder piston 68 forms the axially movable boundary of the master cylinder outlet pressure chamber 78 , which is axially fixed to the housing by the end face 79 of the master cylinder housing 67 . The master cylinder piston 68 is urged 63 corresponding basic position by a braced on this Endstirnewand 79 return spring 81 in its illustrated, the unactuated condition of the master cylinder, that of the output pressure space 78 limiting piston flange is marked on the stop tubes 26 71 by rear contact. This piston flange 71 is provided with a central valve, generally designated 82 , which, in the particular exemplary embodiment shown, is designed as a disk-seat valve, the valve body 83 of which is closed by a valve spring 84 into the closed position which blocks the outlet pressure chamber 78 from the trailing chamber 73 is pushed and held in this closed position by a brake pressure prevailing in the outlet pressure chamber 78 . In the basic position of its piston 68 corresponding to the non-actuated state of the single-circuit master cylinder 63 , this central valve 82 is held in its open position by axial support of a tappet-shaped extension 86 of its valve body 83 on the stop tube 76 , in which the outlet pressure chamber 78 of the single-circuit master cylinder 63 is communicatively connected to its trailing space 73 . This central valve 82 is designed such that after a small initial section of the brake pressure build-up stroke of the master cylinder piston 68 it reaches its blocking position, in which the build-up of brake pressure in the outlet pressure chamber 78 is possible. The single-circuit master cylinder 63 is pressure-tightly attached to the housing of the pneumatic drive cylinder 64 , designated 87 as a whole, which is arranged coaxially with the single-circuit master cylinder 63 , that is to say with the latter, along a common central longitudinal axis 88 . The bore 66 of the master cylinder housing 67 opens into a vacuum chamber 89 of the pneumatic drive cylinder 64 , which is axially movably delimited by a large-area drive piston 91 against a drive chamber 92 of the pneumatic drive cylinder, which can be exposed to the ambient pressure - atmospheric pressure. The - movable - sealing of the drive piston 91 against the housing 87 of the pneumatic drive cylinder 64 mediates a roller membrane 93 , as is known per se from the vacuum brake booster technology.

The drive piston 91 of the pneumatic drive cylinder 64 engages centrally via a plunger 94 axially penetrating its vacuum chamber 89 against the piston flange 72 of the master cylinder piston 68 forming the seal of the trailing chamber 73 of the master cylinder 63 against the vacuum chamber 89 of the pneumatic drive cylinder. The drive piston 91 is further provided with a guide rod 95 extending along the central longitudinal axis 88 , which is displaceably sealed against a central bore 96 of a block-shaped housing part 97 , which in turn is tightly sealed with the boundary of the drive chamber 92 of the pneumatic drive cylinder 64 which is fixed to the housing Part of its housing 87 is connected. In the illustrated basic position of the drive piston 91 and the master cylinder piston 68 , this guide rod 94 protrudes from this block-shaped housing part 97 with a distance of its length corresponding to the maximum displacement path of the drive piston 91 .

To monitor the position of the drive piston 91 , a toggle switch 99 which can be actuated by a radial control rib 98 of the guide rod 95 is provided and which, for. B. generated as a high-level voltage signal pending output signal when the drive piston 91 of the pneumatic drive cylinder 64 and with this the master cylinder piston 68 have experienced an approximately 1/5 to 1/3 of their maximum working or brake pressure build-up corresponding shift.

Connection piece through which the vacuum chamber 89 of the pneumatic drive cylinder 64 to a vacuum source, for. B. the intake manifold of the vehicle engine 11 can be connected or the drive chamber 92 of the pneumatic drive cylinder 64 can be exposed to atmospheric pressure, are denoted by 101 or 102 .

Furthermore, a function control valve 103 is provided in the context of the auxiliary pressure source 56 , in the alternative function positions 0 and I of which the pneumatic drive cylinder 64 is activated or “switched off”.

In the special embodiment shown in FIG. 1, this function control valve 103 is designed as a 3/2-way solenoid valve, in the basic position 0 of which the vacuum chamber 89 of the pneumatic drive cylinder 64 is connected to the vacuum source, but the drive pressure chamber 92 , which in the embodiment according to Fig. 1 is permanently under atmospheric pressure, is blocked against the vacuum chamber 89 . This basic position 0 of the function control valve 103 is assigned to both the normal braking operation and the traction control operation of the braking system 10 .

In the functional position I assumed when the control magnet 104 of the function control valve 103 is excited, the vacuum chamber 89 and the drive chamber 92 of the pneumatic drive cylinder 64 are communicatively connected to one another, but are blocked off from the vacuum source.

In the exemplary embodiment according to FIG. 1, because of the permanent loading of the drive chamber 92 with the atmospheric pressure and, in principle, also permanent connection of the vacuum chamber 89 of the pneumatic drive cylinder 64 to the vacuum source at the pressure outlet 57 of the auxiliary pressure source 56, a high outlet pressure is always present, which if necessary Drive-slip control by switching the pressure supply control valve 58 into its excited position II can be coupled very quickly into the brake circuit II of the vehicle wheels which can be subjected to the control.

The single-circuit master cylinder 63 in combination with its pneumatic drive cylinder 64 acts here as a high-pressure accumulator, which, however, can be "exhausted" due to inevitable leakage losses, which is reflected in the special design of the auxiliary pressure source 56 , as explained with reference to FIG. 1 . that the master cylinder piston 68 experiences a shift in the sense of a reduction in the volume of the outlet pressure chamber 78 of the single-circuit master cylinder 63 , and with it also the drive piston 91 of the pneumatic drive cylinder 64 . Such a displacement of the pistons 68 and 91 would, if they lasted long enough, lead to a failure of the traction control device 13 . To avoid this, the monitoring switch 99 is provided, which emits a high-level voltage output signal when the radial control rib of the guide rod 95 of the drive piston 91 passes an actuating lever 106 . In the electronic control unit 50, this output signal is subjected to a logical combination with a signal which is characteristic of the activation of the traction control system and with the output signal of the brake light switch 49 , in that when the traction control system is neither activated nor braked is, by the output signal of the monitoring switch 99, the function control valve 103 for a minimum period of time t _s of z. B. 1 s is switched to its excited position I so that, for this period t _s both the drive chamber 92 and the vacuum chamber 89 are under atmospheric pressure, with the result that the return spring 81 of the single-circuit master cylinder 63 whose piston 68 and this also pushes the drive piston 91 back into the basic positions shown in FIG. 2 and thereby a maximum volume of brake fluid can be taken up again by the outlet pressure chamber 78 . This type of switchover of the function control valve 103 thus ensures that a sufficient volume of brake fluid is contained in the single-circuit master cylinder 63 for the feasibility of a traction control system.

Instead of the auxiliary pressure source 56 shown in FIG. 1, the auxiliary pressure source 56 'shown in FIG. 3, to the details of which is now referred to, can also be used in the context of the traction control system 13 according to FIG. 1, which is different from the former differs essentially in that, instead of a pneumatic drive cylinder, a hydraulic drive cylinder 107 is provided for actuating the single-circuit master cylinder 63, which has the same structure in the auxiliary pressure source 56 'as described with reference to FIG. 2, so that with regard to the explanation of the single-circuit Master cylinder 63 can be referred to the description given with reference to FIG. 2.

The hydraulic drive cylinder 107 is designed as a structural unit which can be attached to the single-circuit master cylinder, the drive cylinder 107 in turn being arranged coaxially with respect to the central longitudinal axis 88 of the single-circuit master cylinder 63 .

The drive cylinder 107 includes a slidable in a bore 108 of a cup-shaped cylinder housing portion 109 drive pistons 111, which is sealed against the housing bore 108th The pot-shaped housing part 109 is, as shown, connected on its bottom side to the mounting flange 112 of the single-circuit master cylinder 63 . The bottom 113 of the pot-shaped housing part 109 has a central bore 114 , the diameter of which is slightly smaller than the diameter of the adjoining bore 66 of the master cylinder housing 67 . In this central bore 114 of the housing base 113 , a guide extension 116 of the drive piston 111 of the hydraulic drive cylinder 107 is displaceably mounted - without special sealing measures, as a result of which the drive piston 111 is guided "tilt-proof" overall.

The diameter D of the bore 108 of the drive cylinder housing 109 , in which the drive flange 117 of the drive piston 111 is displaceably guided in a pressure-tight manner, is significantly larger than the diameter d of the master cylinder piston 68 . Through the drive flange 117 of the piston 111 of the drive cylinder 107 , a compensation chamber 118 , which extends between this drive flange 117 and the housing base 113 and is vented to the outside, is delimited in a pressure-tight manner against a drive pressure chamber 119 , the housing-fixed - axial - delimitation of which by a pressure-tight to the Pot-shaped housing part 109 attached end plate 121 is formed, on which the supply connection 122 is arranged, via which the output pressure of a hydraulic pressure supply unit can be coupled into the drive pressure chamber 119 or this can be relaxed towards the reservoir 124 of the pressure supply unit 123 . The movement coupling between the drive piston 111 of the hydraulic drive cylinder 107 and the master cylinder piston 68 is provided by a plunger 126 with convex-dome-shaped ends, which are supported on concave-dome-shaped counter surfaces arranged at the bottom of the conical recesses of the master cylinder piston 68 and the extension 116 of the drive piston 111 , the radius of curvature of which is slightly larger than that of the tappet ends, so that the tappet 126 has a slight radial mobility, which allows a slightly off-axis arrangement of the master cylinder 63 and the drive cylinder 107 to compensate.

The pressure supply unit 123 of the auxiliary pressure source 56 'comprises an electrical - controlled as needed - or permanently driven by the vehicle engine hydraulic pump 127 , depending on the type of other uses of the pressure supply unit 123 , be it as an auxiliary pressure source for a power steering device of the vehicle or a level control of the same , works at an outlet pressure level between 8 and 120 bar.

The function control valve 103 is in turn designed as a 3/2-way solenoid valve, as already explained with reference to the exemplary embodiment according to FIG. 1. In contrast to this, however, the function control valve 103 is actuated in such a way that in its basic position 0 the drive pressure chamber 119 of the hydraulic drive cylinder 107 is relaxed towards the reservoir 124 of the pressure supply unit 123 and the function control valve 103 only when the drive Slip control is switched to its excited position I, in which the output pressure of the hydraulic pump 127 is coupled into the drive pressure chamber 119 of the hydraulic drive cylinder 107 and thereby a brake pressure required for the drive slip control is built up in the output pressure chamber 78 of the single-circuit master cylinder 63 .

The actuation of the pressure supply control valve 58 and the brake pressure control valves 33 and 34 of the driven vehicle wheels is otherwise carried out for the purpose of traction control as explained with reference to the embodiment of FIG. 1. The media separation required in the auxiliary pressure source 56 'according to FIG. 3 between the brake circuit II operated with brake fluid medium and the pressure supply unit 123 operated with hydraulic oil as the working medium is achieved by the between the drive flange 117 of the drive piston 111 and the master cylinder piston 68 of the single-circuit master cylinder 63 arranged - unpressurized - compensation chamber 118 of the hydraulic drive cylinder 107 guaranteed.

Since in an ASR 13 , which is realized with an auxiliary pressure source 56 'according to FIG. 3, the brake pressure required for the drive slip control in the single-circuit master cylinder 63 is built up only with the onset of the drive slip control, and consequently the master cylinder piston 68 and the drive piston 111 in normal braking and also in an anti-lock controlled braking assume their illustrated maximum volume of the master cylinder outlet pressure chamber 78 of the master cylinder 63 or minimum volume of the drive pressure chamber 119 of the hydraulic drive cylinder 107 corresponding monitoring is the relevant Piston positions e.g. B. by means of a to the monitoring switch 99 , as shown in FIGS. 1 and 2 in connection with the auxiliary pressure source 56 , not required and in this respect a simplification compared to the auxiliary pressure source 56 achieved.

Is used this simplification, according to even with the auxiliary pressure source 56 in FIGS. 1 and be exploited 2 when the function control valve 103, as indicated by dashed lines in the lower part of FIG. 2, so that in the normal position 0 of this valve 103, the atmospheric pressure, both in the drive chamber 92 and also into the vacuum chamber 89 of the pneumatic drive cylinder 64 , but this is blocked off from the vacuum source - intake manifold of the vehicle engine 11 - and therefore in the functional position I assumed when the valve 103 is excited, the vacuum chamber 89 communicates with the vacuum source , but this is blocked against the drive chamber 92 of the pneumatic drive cylinder 64 . It is then only necessary to accept a slightly slower response of the traction control system.

Whenever the auxiliary pressure source 56 or 56 'is operated in such a way that brake pressure in the master cylinder 63 is built up only when the traction control system begins, the ASR 13 can also be further simplified in that instead of an electrically controllable pressure supply control valve 58 As shown in FIG. 1, a pressure-controlled pressure supply control valve 128 is provided, for which a special design and insertion into the brake system 10 from its ASR 13 is specified in FIG. 4, to the details of which reference is now made. This pressure supply control valve 128 is designed as a 3/2-way changeover valve, which is forced by a return spring into its normal position, which can be subjected to normal operation or to an anti-lock control, braking position 0, in which the pressure output 24 assigned to the brake circuit II of the driven vehicle wheels Master cylinder 22 of the brake system 10 is communicatively connected to the branch point 29 of the main brake line 27 of this brake circuit II, but this branch point 29 is blocked off against the pressure outlet 57 of the auxiliary pressure source 56 or 56 '.

As soon as sufficient pressure is present at this pressure output 57 - with the onset of the traction control system - the pressure supply control valve 128 - pressure-controlled - is switched to its functional position I assigned to the traction control operation mode, in which the pressure output 57 now Auxiliary pressure source 56 or 56 'communicating with the junction 29 of the main brake line 27 of the rear axle brake circuit II connected, this junction 29 is blocked off against the rear axle brake circuit II associated pressure output 24 of the master cylinder 22 of the brake system 10 .

For safety, the pressure supply control valve 128 is - in addition to the control chamber 131 - by acting on it with the output pressure of the auxiliary pressure source, the switching of the valve 128 into its functional position I is provided with a second control chamber 132 which, when the master cylinder 22 is actuated with the is applied to the pressure output 24 output brake pressure and thereby the pressure supply control valve 128 - in addition to the return spring 129 - "forces" in its normal position 0.

The exemplary embodiment of a traction control system according to the invention shown in FIG. 5, to the details of which is now to be referred to, is intended for a vehicle in which, in contrast to the exemplary embodiments explained above, all have their wheel brakes 14 , 16 , 17 and 18 represented wheels are driven. The auxiliary pressure source 56 ″ here has two pressure outputs 57 ′ and 57 individually assigned to the brake circuits I and II, at which the brake pressure which can be coupled into the brake circuits I and / or II in the drive slip control mode is provided. The master cylinder 63 'provided as the brake pressure generating element of the auxiliary pressure source 56 ' is - accordingly - designed as a two-circuit master cylinder, which can be implemented in tandem or in twin construction, such that the piston, which limits the outlet pressure chambers of this master cylinder 63 ', is movable of a single hydraulic or pneumatic drive cylinder 64 or 107 , as explained with reference to FIGS. 2 and 3, but can be driven in accordance with a greater drive force requirement with an increased design. For the two brake circuits I and II, a pressure supply control valve 58 or 128 is provided, which, as shown in the left part of FIG. 5 for the front axle brake circuit I, as an electrically controllable 3/3-way solenoid valve 58 , or , as shown for the rear axle brake circuit II, can be designed as pressure-controlled valves, as already explained in detail with reference to FIGS. 1 and 4.

It is understood that the illustration selected in FIG. 5 of an electrically controllable pressure supply control valve 58 for the front axle brake circuit I in combination with a pressure-controlled supply control valve 128 for the rear axle brake circuit II is only intended to explain both possibilities In practice, however, pressure supply control valves 58 or 128 of the same type are expediently used in a drive-slip control device 13 for a vehicle with all-wheel drive.

While in the exemplary embodiments of the traction control system according to the invention explained in FIGS. 1 to 5, it was tacitly assumed that the single-circuit master cylinder 63 used for the control is only used for the traction control, this master cylinder 63 is used for the variants to be explained below with reference to FIGS. 6a and 6b are also used in normal braking operation for the build-up of brake pressure on the rear axle brake circuit II, in order in this way to achieve a front axle / rear axle brake force distribution which, compared to that in the entire braking area , including the full braking range designed for stable dynamic deceleration behavior of the vehicle braking force distribution with a fixed distribution ratio, in the partial braking area results in an increased rear axle braking force.

To explain a first variant in this regard, reference is first made to the details of FIG. 6a, which shows a brake system 10 , the structure of which corresponds to that of the brake system 10 according to FIG. 4, a single-circuit master cylinder 63 with a pneumatic drive cylinder 64 being included in the auxiliary pressure source 56 , as explained with reference to FIG. 2, is provided, and wherein for the brake system 10 according to FIG. 6a it is further assumed that the two-circuit master cylinder 22 with a pneumatic brake booster 21 , such as. B. in "Bremsen-Handbuch, Alfred Teves GmbH, 9th edition, 1986, pages 93-101, Bartsch-Verlag, Ottobrunn near Munich", is equipped.

Are in the embodiment according to Fig 6, the vacuum chamber 89 'of the brake booster 21 of the tandem master cylinder 22 of the brake system 10 and the negative pressure chamber 89 of the single-circuit master cylinder 63 via a respective (sub) pressure line 133 and 134, permanently connected to the vacuum source -. Z . B. the intake manifold of the vehicle engine 11 - connected. As the ASR function control valve, a 2/2-way valve solenoid valve 136 is provided, the basic position 0 of which is its blocking position, in which the drive chamber 92 of the pneumatic drive cylinder 64 of the single-circuit master cylinder 63 is blocked against the surrounding atmosphere, and the latter at Excitation of its control magnet 137 with an energized position I assumed by the activation signal emitted by the electronic control unit 50 is its flow position, in which the ambient pressure (atmospheric pressure) is coupled in via the connecting piece 102 into the drive chamber 92 of the pneumatic drive cylinder 64 . As a further function control valve 138 is also a 2/2-way valve solenoid valve is provided, the basic position 0 is its flow position, in which the drive chamber 92 of the pneumatic drive cylinder 64 of the single-circuit master cylinder 63 with the drive chamber 92 ' Brake booster 21 of the two-circuit master cylinder 22 are connected to one another via a control line designated overall by 139 , and its excited position I is its blocking position, in which the drive chambers 92 and 92 'of the pneumatic drive cylinder 64 and the brake booster 21 are blocked off from one another.

This blocking position of the further function control valve 138 and the excited position I - the flow position - of the ASR function control valve 136 are assigned to the traction control operation, which is completely analogous to that of the exemplary embodiments described above.

Associated with the braking operation, both normal and subject to an anti-lock control, is the blocking position 0 of the ASR function control valve 136 and the flow position 0 of the further function control valve 138 , in which the by means of the brake pedal 19 and the - not shown - Brake valve of the brake booster 21 of the tandem master cylinder 22 controlled drive pressure is coupled into both the drive chamber 92 'of the brake booster 21 and the drive chamber 92 of the pneumatic drive cylinder 64 of the single-circuit master cylinder 63 .

Due to the cross-sectional design of the master cylinder piston 68 delimiting its outlet pressure chamber 78, the single-circuit master cylinder 63 is designed such that it provides a higher outlet pressure than brake pressure than the master cylinder 22 at the pressure outlet 24 assigned to the rear axle brake circuit II. As a result, the pressure supply control valve 128 is switched to its functional position I during braking, in which the higher output pressure of the single-circuit master cylinder 63 can be coupled into the rear wheel brakes 17 and 18 and thus achieves an increased rear axle braking force component.

The "overbraking" of the rear axle resulting from such a process is "compensated" again by the anti-lock braking system 12 .

In the event that the anti-lock braking system 12 is not functional, which can be recognized by means of the usual test and safety circuits which are provided in the context of the electronic control unit 50 , the latter generates a signal by which the further function control valve 138 is in its blocking position I switched and thus the single-circuit master cylinder 63 switched off, that is, excluded from participation in the brake pressure build-up in the rear axle brake circuit II. In this case, the malfunction of the anti-lock braking system 12 is braked with the brake force distribution, which is predetermined by the dimensioning and design of the master cylinder 22 and is stable throughout the braking range and has dynamic braking behavior.

The variant of drive-slip control device 13 with two 2/2-way solenoid valves 136 and 138 as function control valves, which is explained in this respect with reference to FIG. 6a, is equivalent to the variant shown in broken lines, in which instead of these two function control valves 136 and 138 a designed as a 3/2-way solenoid function control valve 141 is provided, in the basic position 0, the drive chamber 92 'of the brake booster 21 of the tandem master cylinder 22 communicating with the drive chamber 92 of the pneumatic drive cylinder 64 communicating, this (r) against the ambient pressure - atmospheric pressure - are shut off, and in its, the drive stage control mode assigned, excited position I, the atmospheric pressure is coupled into the drive chamber 92 of the pneumatic drive cylinder 64 and this is blocked against the drive chamber 92 'of the brake booster 21 .

Also in the exemplary embodiment shown in FIG. 6b, to the details of which reference is now made, with a single-circuit master cylinder 63 which is involved in braking on the brake pressure build-up in the rear axle brake circuit II, for the purpose of the explanation, this is for the exemplary embodiments provided the single circuit master cylinder 63 according to Fig. 6a presupposed design of the brake booster 21 of the tandem master cylinder 22 and the pneumatic drive cylinder 64. In contrast to this, however, a pressure supply control valve - instead of the pressure-controlled 3/2-way valve, an - electrically controllable - 3/3-way solenoid valve 58 is provided, as also in the embodiment according to FIG. 1.

In a further functional correspondence with this, the auxiliary pressure source 56 is also operated in the embodiment according to FIG. 6b in such a way that the highest possible outlet pressure of the auxiliary pressure source 56 is provided at its pressure outlet 57 as long as there is no braking. For drive slip control, only the pressure supply control valve 58 , which in this respect also fulfills the function of an ASR function control valve, then has to be switched into its energized position II, in which the pressure output 57 of the auxiliary pressure source 56 is connected to that of the pressure supply Control valve 58 to the branch point 29 of the rear axle brake circuit II continuing section 27 '″ of the main brake line of the rear axle brake circuit II is connected.

. Also, in the embodiment of Figure 6b, the vacuum chambers 89 and 89 'of the pneumatic drive cylinder 64 and the brake booster 21 are permanently attached to the vacuum source - connected - at the selected explanatory example, to the inlet connection of the vehicle engine 11.

As part of the auxiliary pressure source 56 connected between a to the driving chamber 92 'connected to the brake booster 21 line section 139' and an output connected to the drive pressure chamber 92 of the pneumatic drive cylinder 64 line portion 139 'is provided as a 2/2-way solenoid valve designed control valve 142, a A total of 139 control line is connected, which is shut off from each other in the illustrated basic position 0 of this control valve 142 and connected to one another in the excited position I of this control valve 142 . As a further control valve 143 of the auxiliary pressure source 56 , a 3/3-way solenoid valve is provided, the basic position 0 of which is a flow position in which the line section 139 ″ of the control line 139 leading from the first-mentioned control valve 142 to the drive chamber 92 of the pneumatic drive cylinder is at atmospheric pressure acted upon and blocked against the vacuum source 11 . The 3/3-way solenoid valve 143 is by energizing its control magnet 144 with a control current of relatively low amperage z. B. 3 A in its excited position I and controllable by excitation of the control magnet 144 with a defined higher current of 6 A in its excited position II. The excited position I is a flow position, in which the pressurized in the basic position 0 with atmospheric pressure line portion 139 "of the control line is blocked 139 against the ambient atmosphere, but connected to the vacuum source 11, in which case a pressure equalization between the drive chamber 92 and The vacuum chamber 89 of the pneumatic drive cylinder 64 takes place, whereby the master cylinder piston 68 of the single-circuit master cylinder 63 reaches its basic position linked to the maximum volume of the outlet pressure chamber 78 of the single-circuit master cylinder 63 .

The energized position II of the 3/3-way solenoid valve 143 is a blocking position, in which said control line section 139 ″ is blocked both against the atmosphere and against the vacuum source 11 . Furthermore, a differential pressure switch 146 is provided which, whenever there are different pressures in the two line sections 139 ′ and 139 ″ of the control line, outputs an output signal through which the 2/2-way solenoid valve 142 is in its excited position I and that 3/3-way solenoid valve 143 can be switched into its energized position II. A triggering of control current pulses, by means of which the 3/3-way solenoid valve is switched into its excited position I - the compensation position - takes place when the brake system 10 is actuated with the response of the brake light switch 49 or by the response of the monitoring switch 99 which As already explained with reference to FIG. 1, a control current pulse for triggering the 3/3-way solenoid valve triggers for a certain period of time, which is long enough for the vacuum compensation to occur between the vacuum chamber 89 and the drive chamber 92 of the pneumatic drive cylinder 64 is.

The drive stage control device 13 according to FIG. 6b, which is explained in terms of its construction, operates in the driving and braking mode of the vehicle as follows:

With the commissioning of the vehicle, that is, as soon as a sufficient negative pressure has developed at the intake manifold of the vehicle engine 11 , this negative pressure prevails - with the brake system 10 not actuated - both in the negative pressure chamber 89 'and in the drive chamber 92 ' of the brake booster 21 and also in the Vacuum chamber 89 of the pneumatic drive cylinder 64 , the drive chamber 92 of which, however, is at atmospheric pressure via the 3/3-way solenoid valve 144 located in its basic position 0. As a result, the single-circuit master cylinder 63 is "pre-tensioned", that is to say that the highest possible outlet pressure is present at the pressure outlet 57 of the auxiliary pressure source 56 , which can be used for traction control by switching the pressure supply or ASR function control valve 58 .

The driver actuates the brake system 10, so the brake light switch 49 is first of all the / 3-way solenoid valve switched 3 144 into its excited position I with the response, in which a pressure balance between the negative pressure chamber 89 and the driving chamber 92 of the pneumatic drive cylinder 64 can take place , whereby the piston 68 of the single-circuit master cylinder 63 is pushed back into its basic position linked to the maximum volume of the outlet pressure chamber 78 as the starting position for a “takeover” of the brake pressure supply in the rear axle brake circuit II. Due to the pressure difference occurring in sections 139 'and 139 ''of the control line 139 as a result of the brake actuation, the differential pressure switch 146 generates an output signal through which, on the one hand, the 2/2-way solenoid valve 142 in its flow position I and, on the other hand, the 3 / 3-way solenoid valve 143 can be switched in its energized position II.

This output signal of the differential pressure switch 146 also switches the pressure supply or ASR function control valve 58 into its excited position II, in which the brake pressure is now coupled into the rear axle brake circuit II from the auxiliary pressure source 56 . Due to the interaction of the control valves 142 and 143 and the pressure supply control valve 58 , which is essentially controlled by the differential pressure switch 146 during braking, it is achieved that the same in the drive pressure spaces 92 'and 92 of the brake booster 21 and the pneumatic drive cylinder 64 of the single-circuit master cylinder 63 Drive pressures prevail and, consequently, the output pressure of the single-circuit master cylinder 63 , which is higher in magnitude, is coupled into the rear-axle brake circuit II. A monitoring switch 99 with the function explained with reference to FIG. 2 is advantageous for safety reasons in all of the exemplary embodiments explained with reference to FIGS. 6a and 6b. The output signal of this monitoring switch 99 is sent via an AND gate 145 , with which a driver stage 147 can be controlled, to trigger the signal which controls the 3/3-way solenoid valve 143 in its functional position I, a first, non-negated input 148 of the AND Linking element 145 is supplied, provided that the output signal of the monitoring switch 99 which is characteristic of a minimum displacement of the drive piston 91 is present as a high-level signal.

A second, negated input 149 and a third, also negated input 151 of the AND logic element 145 are the output signal of the brake light switch 49, which is present as a high-level signal during braking, and an output signal of the electronic control unit, also generated as a high-level signal 50 , which delivers this when the traction control system is activated, each supplied individually.

Claims (16)

1. Drive-slip control device (ASR) for a road vehicle also equipped with an anti-lock braking system (ASR) with a hydraulic multi-circuit brake system, which comprises at least one brake circuit assigned to driven vehicle wheels and another brake circuit assigned to non-driven or likewise driven vehicle wheels , Brake pressure control valves provided for the ABS, designed as solenoid valves, which, controlled by output signals from an electronic ABS and ASR control unit, can be switched into brake pressure build-up, brake pressure maintenance and brake pressure reduction positions, for the drive slip. Control are used analogously, which works on the principle of retarding a vehicle wheel that tends to spin by activating its wheel brake, an auxiliary pressure source being provided for the ASR, which is used to activate the traction control via a pressure supply control valve on the or the brake circuit (s) of the Driven vehicle wheels can be connected and a master cylinder which can be actuated via a brake booster is provided as the braking device of the brake system, characterized in that an additional master cylinder ( 63 ) is provided for the at least one brake circuit (II) associated with driven vehicle wheels and serves as a drive element for its piston ( 68 ) a pneumatic or hydraulic drive cylinder ( 64; ) corresponding to the structure of the drive element of the brake booster ( 21 ) of the brake device ( 21, 22 ) of the brake system ( 10 ) . 107 ), which can be acted upon by valve-controlled connection of its working chamber (s) to the auxiliary power source of a brake booster ( 21 ) of the brake device ( 21, 22 ) in the sense of a build-up of brake pressure in the additional master cylinder ( 63 ). 2. Drive-slip control device according to claim 1, characterized in that for a vehicle with all-wheel drive, the additional master cylinder ( 63 ') in tandem or twin design with two, one of the two brake circuits (I and II) assigned Output pressure spaces is formed, and that a pressure supply control valve ( 58 and / or 128 ) is provided for each of the two brake circuits (I and II). 3. Drive-slip control device according to claim 1 or claim 2, characterized in that the pressure supply control valve ( 58 ) provided for each brake circuit (I and / or II) is designed as a 3/3-way solenoid valve, the basic position of which 0 is a flow position in which the pressure output of the braking device ( 21, 22 ) assigned to the brake circuit is connected to the brake line branches ( 27 'and 27 ''or 26 ' and 26 '') leading to the wheel brakes and the auxiliary pressure source ( 56; 56 ') Is blocked against these line branches, which when activated with a control current defined, relatively low current intensity (z. B. 3A) excited position I is a blocking position in which both the master cylinder pressure output ( 23 and / or 24 ) and the auxiliary pressure source ( 56; 56 ') are shut off against the brake circuit (I or II) and the latter when excited with a defined, relatively higher control current (e.g. 6A), second excited position II is a functional position in which the auxiliary pressure source ( 56; 56 ') connected to the brake circuit (II and / or I), but this is blocked against the assigned pressure output ( 23 and / or 24 ) of the master cylinder ( 22 ) of the brake system ( 10 ). 4. Drive-slip control device according to claim 1 or claim 2, characterized in that the respective one brake circuit (I and / or II) associated pressure supply control valve ( 128 ) is designed as a pressure-controlled 3/2-way valve which by the in the master cylinder ( 22 ) generated brake pressure is switched to its functional position 0, in which the master cylinder ( 22 ) is connected to the brake circuit (I or II) and the auxiliary pressure source ( 56; 56 ') is blocked against this, and by the output pressure of additional master cylinder ( 63 ) of the auxiliary pressure source ( 56; 56 ') in its connecting this with the brake circuit (II and / or I) and against the master cylinder ( 22 ) blocking position I is switched. 5. Drive slip control device according to one of the claims 1 to 4, characterized in that the auxiliary pressure source during of normal driving and braking, as well as one Brake control subject to anti-lock control low output pressure level is maintained and with the Insert the traction control system on the Operating state with high output pressure level switched becomes. 6. traction control device according to claim 5 for a vehicle with a pneumatic brake booster, which is permanently connected to a vacuum source of the vehicle, for. B. has the intake manifold of a gasoline engine, connected vacuum chamber and a higher by the pedal actuation of a brake valve, a higher, proportional to the pedal pressure pressure drive chamber, which is the amount between the pressure in the vacuum chamber and the atmospheric pressure, characterized in that the The drive chamber ( 92 ) of the pneumatic drive cylinder ( 64 ) of the additional master cylinder ( 63 ) is permanently under the atmospheric ambient pressure and that a solenoid valve ( 103 ) which can be controlled by output signals from the electronic control unit ( 50 ) is provided, in its associated with normal driving and braking operation Basic position 0, the vacuum chamber ( 89 ) and the drive chamber ( 92 ) are connected to one another and blocked against the vacuum source ( 11 ) and, in the excited position I associated with the drive slip control operation, the vacuum chamber ( 89 ) with the bottom rdruckquelle ( 11 ) connected and blocked against the drive chamber ( 92 ) ( Fig. 2). 7. traction control device according to claim 5 for a vehicle with a pneumatic brake booster, which is permanently connected to a vacuum source of the vehicle, for. B. has the intake manifold of a gasoline engine, connected vacuum chamber and a higher by the pedal actuation of a brake valve, a higher, proportional to the pedal pressure pressure drive chamber, which is the amount between the pressure in the vacuum chamber and the atmospheric pressure, characterized in that the Vacuum chamber ( 89 ) of the pneumatic drive cylinder ( 64 ) of the further master cylinder ( 63 ) is permanently connected to the vacuum source ( 11 ) and that a solenoid valve arrangement which can be controlled by output signals of the electronic control unit ( 50 ) is provided, in the normal driving mode and the braking mode assigned to it Functional position, the vacuum chamber ( 89 ) is connected to the drive chamber ( 92 ) and this is shut off from the atmosphere and in its excited functional position assigned to the traction-slip control mode, the drive chamber ( 92 ) is below the atmospheric Ambient pressure is and is blocked against the vacuum chamber ( 89 ). 8. Drive-slip control device according to claim 5 for a vehicle with a hydraulic brake booster, in which a hydraulic drive cylinder is provided for the brake pressure build-up displacement of the master cylinder piston, which has a drive pressure chamber, in which a via a proportional valve to that exercised by the driver The actuating force proportional to the drive pressure derived from the high output pressure of a pressure supply unit can be coupled in, characterized in that the hydraulic drive cylinder ( 107 ) of the additional master cylinder ( 63 ) has a drive pressure chamber (pressure-tightly delimited by a piston ( 111 ) against a compensation chamber ( 118 ) kept under atmospheric pressure) ( 119 ), in a basic position 0 assigned to normal driving and braking operation, of a solenoid valve ( 103 ) which can be switched over by ASR control signals from the electronic control unit ( 50 ) to the unpressurized reservoir ( 124 ) of the pressure supply - Unit ( 122 ) is relieved and blocked against the pressure outlet of the pressure supply unit ( 123 ), and in the excited position I of the solenoid valve ( 103 ) assigned to the traction-slip control mode, connected to the high-pressure outlet of the pressure supply unit ( 122 ) and against whose reservoir ( 124 ) is shut off ( Fig. 3). 9. traction control device according to one of claims 1 to 4, characterized in that the auxiliary pressure source ( 56; 56 ') is kept permanently at a high output pressure level, wherein in control phases of the traction control system the pressurization of the wheel brake subject to the control (n) by controlling a pressure supply control valve ( 58 ) designed as a solenoid valve and in that a position transmitter ( 99 ) monitoring the position of the piston of the drive cylinder ( 64; 107 ) of the additional master cylinder ( 63 ) is provided, starting from a minimum displacement of the piston ( 91; 111 ) generates an electrical output signal by means of which a relief valve can be controlled for a minimum period of time into an equalization position in which the drive pressure chamber of the drive cylinder ( 64; 107 ), in the case of a pneumatic drive cylinder with the vacuum chamber ( 89 ) connected, in the case of a hydraulic drive cylinder ( 107 ) to the reservoir container ( 124 ) of the pressure supply unit ( 123 ) is relieved. 10. Drive-slip control device according to claim 9 for a vehicle with a pneumatic brake booster, which has a permanently connected to a vacuum source of the vehicle vacuum chamber and a pedal chamber of a brake valve, a higher, proportional to the pedal force pressure drive chamber, the amount between the pressure prevailing in the vacuum chamber and the atmospheric ambient pressure, characterized in that the vacuum chamber ( 89 ) of the drive cylinder ( 64 ) of the additional master cylinder ( 63 ) is permanently connected to the vacuum source ( 11 ) and the drive chamber ( 92 ) is below the atmospheric pressure is maintained and that the pressure equalization takes place by temporarily connecting the vacuum chamber ( 89 ) to the drive chamber ( 92 ). 11. Drive-slip control device according to claim 9 for a vehicle with a pneumatic brake booster, which has a permanent vacuum chamber connected to a vacuum source of the vehicle and a pedal actuation of a brake valve a higher, proportional to the pedal force pressure drive chamber, the amount between the pressure prevailing in the negative pressure chamber and the atmospheric ambient pressure, the negative pressure chamber of the drive cylinder of the additional master cylinder being permanently connected to the negative pressure source and the drive chamber being kept below the atmospheric ambient pressure, characterized in that the temporary pressure equalization occurs by connecting the drive chamber ( 89 ) the vacuum source ( 11 ) is carried out with simultaneous shut-off against the atmospheric pressure. 12. Drive-slip control device according to one of claims 1 to 4 for a vehicle with front axle / rear axle brake circuit division, characterized in that the auxiliary pressure source ( 56; 56 ') of the ASR ( 13 ) in braking operation as a pressure source for the rear axle Brake circuit (II) is used and provides a pressure that is proportional to the pressure provided on the master cylinder ( 22 ) of the brake system ( 10 ) for the rear axle brake circuit (II), but is higher than this. 13. Drive-slip control device according to claim 12 for a vehicle with a pneumatic brake booster, which has a permanent vacuum chamber connected to a vacuum source of the vehicle and a pedal actuation of a brake valve, a higher, proportional to the pedal force pressure drive chamber, the amount between which pressure prevailing in the vacuum chamber and the atmospheric ambient pressure, characterized by the following features:

• a) the vacuum chamber ( 89 ) of the pneumatic drive cylinder ( 64 ) of the additional master cylinder ( 63 ) is permanently connected to the vacuum source ( 11 );
• b) in normal driving and braking operation, the drive chamber ( 92 ) of the pneumatic drive cylinder ( 64 ) of the additional master cylinder ( 63 ) with the drive chamber ( 92 ') of the brake booster ( 21 ) of the master cylinder ( 22 ) of the brake system ( 10 ) and cordoned off from the surrounding atmosphere;
• c) in traction control mode, the drive chamber ( 92 ) of the pneumatic drive cylinder ( 24 ) against the drive chamber ( 92 ') of the brake booster ( 21 ) is blocked and kept under atmospheric pressure.

14. Drive-slip control device according to claim 13, characterized in that a first as a 2/2-way solenoid valve designed ASR control valve ( 138 ) is provided, the basic operation associated with the braking operation 0 its the drive chambers ( 92 'and 92 ) of the brake booster ( 21 ) and the pneumatic drive cylinder ( 64 ) is the flow position connecting one another and its excited position I assigned to the traction-slip control mode is its blocking position and a second ASR control valve ( 136 ), whose basic position 0 assigned to the braking operation is its blocking position and whose excited position I assigned to the traction control operation is a flow position in which the atmospheric ambient pressure is coupled into the drive chamber ( 92 ) of the pneumatic drive cylinder ( 64 ) ( FIG. 6a) . 15. Drive slip control device according to claim 13, characterized in that a 3/2-way solenoid valve designed function control valve ( 141 ) is provided, the normal position of which is associated with normal braking operation 0 is a flow position in which the drive chambers ( 92 'and 92 ) of the brake booster ( 21 ) and the pneumatic drive cylinder ( 64 ) and the pneumatic drive cylinder ( 64 ) are connected to one another, but are sealed off from the atmosphere and whose function position I assigned to the drive slip control mode is a second flow position , in which the atmospheric ambient pressure is coupled into the drive chamber ( 92 ) of the pneumatic drive cylinder ( 64 ), but this is shut off against the drive chamber ( 92 ') of the brake booster ( 21 ) ( Fig. 6a). 16. Drive-slip control device according to claim 12 for a vehicle with a pneumatic brake booster, characterized by the following features:

• a) the vacuum chambers ( 89 'and 89 ) of the brake booster ( 21 ) of the braking device ( 21, 22 ) and the drive cylinder ( 64 ) of the additional master cylinder are permanently connected to the vacuum source ( 11 );
• b) between the drive chamber ( 89 ') of the brake booster ( 21 ) and the drive chamber ( 92 ) of the pneumatic drive cylinder ( 64 ) of the additional master cylinder ( 63 ) is a 2/2-way solenoid valve control valve ( 142 ) connected, the Home position is its blocking position and its energized position I is its flow position which is associated with normal braking operation, this control valve ( 142 ) being switched into its energized position I by the brake output signal of the brake light switch ( 49 );
• c) a 3/3-way solenoid valve ( 143 ) is provided which has a functional position 0 as the basic position, in which the atmospheric ambient pressure is coupled into the drive chamber ( 92 ) of the drive cylinder ( 64 ) of the additional master cylinder ( 63 ), a first excited position I, in which the vacuum source ( 11 ) is connected to the drive chamber ( 92 ) and this is shut off from the atmosphere, and a further excited position II, a blocking position, in which the drive chamber ( 92 ) both against the atmosphere and is also blocked against the vacuum source ( 11 );
• d) the 3/3-way solenoid valve ( 143 ) can be controlled by the output signal of the brake light switch ( 49 ) into its excited position I, in which the vacuum chamber ( 89 ) of the drive cylinder ( 64 ) of the further master cylinder ( 63 ) with the vacuum source ( 11 ) is connected;
• e) a differential pressure switch ( 146 ) is provided which, whenever, the pressures prevailing in the drive chambers ( 89 'and 89 ) of the brake booster ( 21 ) or the drive cylinder ( 64 ) are different, generates an output signal by which 2/2-way solenoid valve ( 142 ) in its energized position I, its flow position, and the 3/3-way solenoid valve ( 143 ) in its energized position II, its blocking position;
• f) a monitoring switch is provided which, when the drive piston ( 91 ) of the pneumatic drive cylinder ( 64 ) has carried out a minimum stroke, but the brake is not actuated and the drive slip control has not responded, generates an output signal through that the 3/3-way solenoid valve ( 143 ) is controlled into its blocking position II for a defined period of time, which is sufficiently dimensioned for pressure compensation in the cylinder chambers ( 89 and 92 ) ( FIG. 6b).