DE2757911A1 - BLOCK PROTECTION CONTROL DEVICE - Google Patents

Description

The invention is based on an anti-lock control device according to the preamble of the main claim. Such Control device is known (DT-OS 2 610 585) · With this known device, the shortest possible braking distance should be achieved can be achieved. However, the driving stability is not sufficient for all vehicle and driving conditions.

The variety of types of commercial vehicles sometimes requires vehicle-specific ones Control loop arrangements. In this case, however, only those arrangements are permissible in which the vehicle is also in extreme road and driving conditions with the shortest possible braking distance, stable and controllable by the driver remain.

Critical driving situations often only occur in certain vehicle and driving conditions. A coordinated one The control loop arrangement is therefore only optimal for this one state.

For example, an empty utility vehicle with a short wheelbase is critical in terms of driving stability. A closed loop arrangement j with the rear axle with common brake pressure control according to the lowest coefficient of road friction would be regulated, i.e. after select low, would therefore be optimal for this empty vehicle state. When the vehicle is loaded on the other hand, if the rear axle has the higher axle load, the select-low control would, however, not allow one long braking distance given. Individual wheel control with individual brake pressure control of the rear axle would be used here represent the optimal control loop arrangement.

Advantages of the invention

The anti-lock control device with the characterizing features of the main claim has the advantage that an optimal controller performance in all vehicle and

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Driving conditions is achieved. Compared to known solutions, better braking of the vehicle is achieved.

drawing

Several exemplary embodiments of the invention are shown in the drawing and in the description below explained in more detail. The figures show: FIG. 1 a switchover logic that can be controlled by the control signal, FIG. 2 a table for the logic states according to FIG. 1, FIG. 3 an advantageous extension of the switching logic according to FIG. 1, 4 shows the logical effects of the switching logic according to FIGS. 1 and 3 and FIGS. 5 to 11 vehicle and driving states, where the switching logic is effective.

description

1 shows a vehicle wheel 1 with a sensor 1 'and a vehicle wheel 2 with a sensor 2'. Each wheel 1 and 2 is assigned an input amplifier 3 'or 4 ¹ and a single wheel control channel 3 or 4 and a common comparator 5.

The individual wheel control channels 3 and 4 supply magnet control signals 6 and 7 to output stages 8 and 9 for controlling Solenoid valves 10 and 11. Before the output stages 8 and 9, two AND gates 12 and 13 are arranged, and the comparator two AND gates 14 and 15 are connected downstream. Between these and the AND gates 12 and 13 are further AND gates 16 and 17, and two OR gates 18 and 19 are provided downstream of these. A control signal carries the Reference number 20.

Mode of action

The wheel speed signals of the wheels 1, 2 supplied by the sensors I ¹ and 2 ¹ , for which the switching is to be effective, are processed in the input amplifiers 3 ¹ and 4 'and fed to a comparator 5 upstream of the respective individual wheel control channel 3 or 4 that by comparison

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selects the lowest of the wheel speeds involved and thus enables "low" detection in the simplest possible way. The output signal of the comparator 5 log 1 or log 0 can be freely assigned to the respective low channel. In the embodiment for example at log 1 the speed of bike 1 is the lower and thus this is the low channel, at log 0 the speed of bike 2 is the lower and thus the speed of bike 2 is the low channel.

The table in Fig. 2 is now only

I) with control signal 20 log 0, the solenoid control signals 6, starting from the individual wheel control channels 3> 4, to the associated output stages 8, 9 to control the solenoid valves 10, 11 separately. In this case, the desired individual wheel control with individual brake pressure control is effective.

The AND-like linkage of the magnet control signals 6 and 7 with control signal 20 gives the passage here of AND gates 12, 13 by negating control signal 20 log 0 for magnet control signals 6, 7 free and at the same time blocks the access of the comparator 5 via the AND gates 14, 15.

II) With control signal 20 log 1, on the other hand, the AND gates 12, 13 enable the magnet control signals to penetrate separately 6, 7 blocked and if there is a low detection log 1 via the AND gates 14, 16 and the OR link 18, 19 the parallel control of the output stages 8, 9 from the magnet control signal 6 released.

III) With control signal log 1 and low detection log 0 becomes on the other hand, via the AND gates 15, 17, the parallel control of the output stages 8, 9 by the magnet control signal 7 released.

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For the sake of clarity, only one solenoid valve 10 or 11 is shown in the logic of FIG. 1. In Usually, however, two solenoid valves and one inlet and one outlet valve are assigned to each control circuit.

In the case of a 2-solenoid valve control, the combination logic which is exactly the same as in FIG. 1 is required for the inlet and outlet solenoid valves. The functionality here is also exactly the same.

FIG. 3 shows a further development of the type according to FIG. 1. Here a control signal 20 ′ is passed on to a timing element 21 and a clock generator 22. A tap 23 for the low signal detection, like the clock generator 22, is placed in front of the solenoid valves 10 'and 11' via two AND switches 2H and 25 and two OR switches 26 and 27, the two solenoid valves 10 'and 11' only inlet -Magnetic valves for wheel 1 or 2 are.

In this embodiment, the fact is taken into account that when switching from select-low to single wheel control especially on asymmetrical lanes the sudden pressure increase of the non-low channel is just as sudden Increases the yaw moment, which must be compensated for by quickly required steering compensation. Here however, the driver is often overwhelmed and critical driving situations also arise.

Therefore, for the first pressure build-up of the Non-low channel only allowed a significantly reduced pressure increase immediately after the switchover.

The trailing edge of the control signal 20 'from log 1 to log 0, which causes the switchover, simultaneously sets a timing element 21 that enables a clock generator 22 for a certain time, which only generates a pulsed and thus flat pressure build-up to the pressure level of the non-low Channel.

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The clock generator 22 acts only on the inlet solenoid valve 10 'or 11'.

4 shows the effectiveness in a brake pressure diagram this advantageous measure. It is on the ordinate the brake pressure and the time t plotted on the abscissa. Curve a shows the brake pressure curve, which up to Time of switchover tu as a common brake pressure control with regulation according to select low for the relevant Wheels is valid.

From time tu, however, there is a delayed build-up of brake pressure according to curve b to the transferable brake pressure level c of the non-low channel. Would the proposed action are not effective, the pressure increase would take place immediately after the switchover according to curve d.

5 shows a limit switch 30 as a transmitter circuit on an actuating linkage 31 of an automatically load-dependent Braking device 32.

As shown in the example already mentioned at the outset, it is advantageous to use an empty vehicle in which, for example the rear axle has the lower axle load, to be regulated according to select low to ensure sufficient driving stability to achieve. On the other hand, when the vehicle is loaded, the high rear axle load means that individual wheel control can be achieved a short braking distance is mandatory.

By coupling the transmitter circuit (travel switch 30) to a load-sensing braking device 32 for generating of a control signal, by switching between the empty and loaded driving conditions, the optimal Control loop arrangement are assigned.

With steel-sprung axles, the encoder circuit can consist of a simple travel switch 30, as shown. which detects the current vehicle condition via the spring deflection.

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In the case of air-sprung axles, the encoder circuit can be switched off consist of a pressure switch that detects the respective load status via the bellows pressure.

A changeover of the control circuit arrangement is also desirable depending on the load in vehicles with trailing axles, which are designed as lifting axles, raised when the vehicle is empty and extended when the vehicle is loaded will. Such a vehicle 33 with a lifting axle 3 ^ is shown in FIG 6 shown.

With the lifting axle 34 raised and thus the vehicle 33 empty a control behavior of the rear axle after select low is urgent because for this vehicle when combined with a trailer through a large overhang S (rear axle to the trailer coupling) with a different control behavior, for example Independent wheel control, no sufficient cornering forces can be provided. First a regulation the rear axle after select low ensures the necessary cornering force for this vehicle in this driving state. When the vehicle is loaded, on the other hand, additional cornering force is applied by the extended lifting axle, so that in this vehicle with this driving condition the rear axle to achieve a short braking distance can be regulated according to individual wheel criteria.

In the case of the vehicle 33, the control signal can be sent directly to an actuating switch for the lifting axle 34 or to an additionally mounted limit switch.

Extensive driving tests have shown that a single-driving, i.e. unsaddled, tractor unit in a row the short wheelbase and the low rear axle load on asymmetrical lanes by the driver only with one Rear axle control is controllable according to select low. In the case of a semi-mounted and loaded tractor-trailer, however Set an impermissibly long braking distance with the same control behavior and on the same lane. There is only one here Individual wheel control justifiable. The control signal can be

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be generated with a transmitter circuit according to FIG. 5 or also on the electrical plug-in unit of the Trailer-towing vehicle cable connection must be attached.

In Fig. 7 with the reference number 35 is a tractor connector and with the reference number 36 a trailer connector is shown. There is also a switch contact 37 and a switch tongue 38 and a control signal 39 are shown. The switching contact 37 on the electrical plug-in unit is more solo-driving when the trailer plug-in connection 36 is not inserted Tractor, closed, so that the control signal 39 log 1 is controlled; with a saddled trailer is dagen the switching contact 37 is open and the state log therefore applies

In Fig. 8 is a wagon train, each with an ABS device 42 and 43 provided on each individual vehicle 40 and 4l. In this design, a warning signal 44 of the trailer for the purpose of switching is except on a warning device of the towing vehicle is also performed on the ABS device 42 of the towing vehicle. The ABS devices 42 and 43 are electronic Switching elements equipped.

In the case of a coupled trailer 41 without ABS or a faulty ABS function in the trailer, the physical Conditions of the regulated and non-regulated wheel during braking processes, sometimes considerable, accumulating Adze forces, which when cornering, for example, partly also via the cornering force of the rear axle of the towing vehicle 40 must be supported.

To compensate for the different decelerations of the individual vehicles towing vehicle and trailer as the cause to achieve the drawbar forces is in this case a reduction in the braking effect of the towing vehicle 40 by regulating the rear axle according to select low is desired. In the case of a solo towing vehicle or a combination of trains with an intact trailer ABS function to achieve a short braking distance, the towing vehicle

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lower axle have a single wheel control behavior.

The control signal required to identify the respective vehicle position can be generated when a trailer is connected be carried out without ABS as in FIG. In the ABS device shown in FIG. 8 installed 43 in the trailer 41, however, the warning signal 44 for the warning device 45, which the driver the faulty trailer ABS function indicates tapped as a control signal.

The control signal, which is to cause the switch to select low, can of course also be directly dependent on the drawbar force be controlled.

9 shows a switching contact 46 on the towing vehicle or trailer coupling device 47. This switching contact 46 recognizes accruing drawbar forces via a spring arrangement 48, and when a set point is reached Threshold value, this causes the control behavior to be switched.

Completely different causes make a switchover of the front axle according to the control behavior select low in the braking phase necessary. As already shown in the explanation of FIG. 3 and FIG. 4, a suddenly becomes effective increasing yaw moment makes considerable demands on the driver's ability to react. Especially when carried out in a panic When braking on asymmetrical lanes, the driver is often overwhelmed and has to deal with a lane offset his vehicle also poses a danger to oncoming traffic.

A select-low control effective at the start of braking on the Front axle, which is described according to the first control cycle or according to a time criterion in FIG. 3 and FIG Switches over to independent wheel control, gives the driver the necessary time, if the vehicle is on the right track to apply the necessary steering angle for yaw moment compensation.

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909826/04

The driving situation is similar with a large steering angle. A large steering angle is required when a large Yaw moment must be compensated or extreme cornering or evasive maneuvers are carried out. The large steering angle is also a measure of the fact that high cornering forces are applied have to. In many cases, these can only be provided by a control according to select low.

So that the switchover does not have a rocking effect on the steering behavior is given, apart from the throttled pressure increase when switching from select low on individual wheel control in the manner described in Fig. 3 and Fig. 4 also a throttled or clocked Pressure drop of the non-low channel when switching from Individual wheel control to select-low control is advantageous.

The logic required for this is implemented similarly to that in FIG. 2, but the clock generator is started from the leading edge controlled by the control signal and acts on the exhaust solenoid valve.

The control signal itself can, as shown in FIG. 10, by means of a simple switching contact 50 on a steering gear 51 can be removed. A cam 52 faces the switching contact 50.

The lateral guide is also severely impaired. ~ " force when a wheel has a large wheel slip over a certain period of time. It may be necessary here be that at least the other wheel of the relevant axle or vehicle side has an optimal cornering force must provide. However, this can only be ensured if this wheel is in a stable state by means of select-low control Slip range is regulated or returned. In this case, the control signal for switching is a slip threshold, which is monitored by a timer to filter out large slip values that are only present for a short time.

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FIG. 11 shows a wheel course in which the control signal only occurs after a certain threshold, despite the slip threshold being reached Time t is effective. The wheel speed V is plotted on the ordinate and time t is plotted on the abscissa. A curve 55 is that of the vehicle speed, a curve 56 that of the wheel 1 regulated according to select low, and a curve that of the other wheel 2. The slip threshold is dashed and bears the reference number 58. Finally, the control signal s is also plotted on the abscissa.

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Claims (12)

December 20, 1977 He / Th Robert Bosch GmbH, Stuttgart Expectations Anti-lock control device for motor vehicles with a control logic that adjusts the brake pressure according to the wheel rotation behavior performs, characterized in that the control behavior of at least two vehicle wheels (1,2) can be changed is and that a single wheel control with individual brake pressure control is automatic for these two vehicle wheels can be switched to a common brake pressure control with control behavior according to select low and vice versa. 2. Anti-lock control device according to claim 1, characterized in that a to switch the control behavior Control signal (20) is used, which can be controlled by a transmitter circuit in critical vehicle and driving conditions. 3. Anti-lock control device according to claim 1 or 2, characterized in that the switching depends on the load takes place, (Fig. 5). 969826/0401 4. Anti-lock control device according to claim 1 or 2 for a vehicle with a lifting axle, characterized in that the changeover depends on the load or on the position of the lifting axle (3 * 0 in the way that at When the vehicle is empty or when the lifting axle is raised, a control behavior is set according to select low (Fig. 6). 5 anti-lock control device according to claim 1 or 2, for a vehicle with a trailer, characterized in that the switchover takes place when a trailer (4l) with or without defective anti-lock device (43) to the towing vehicle (40) coupled, preferably on the rear axle (Fig. 8). 6. Anti-lock control device according to claim 1 or 2 for a tractor-trailer, characterized in that the switching with the semi-trailer unhitched, on at least one rear axle ■ of the tractor. 7 anti-lock control device according to claim 1 or 2, characterized in that the switchover takes place when a high drawbar force is established due to the trailer approaching at least on the wheels of one axle of the towing vehicle (Fig. 9) 8. anti-lock control device according to claim 1 or 2, characterized characterized in that the switchover takes place at a large steering angle on the wheels of an axle, preferably on the steering axle (Fig. 10). 909826/0401 " ³ " 9. anti-lock control device according to claim 1 or 2, characterized in that the switchover at large, over Wheel slip lasting a certain time takes place (Fig. 11). 10. anti-lock control device according to claim 1 or 2, characterized in that for the first pressure build-up of the Non-low channel immediately after the switchover only a significantly reduced pressure increase is permissible (Fig. 3 and 4). 11. Anti-lock control device according to claim 1 to 10, characterized in that immediately after the switchover from select low to single wheel control for the first pressure increase of the non-low channel only a throttled pressure increase is allowed (Fig. 3 and Fig. M). 12. Anti-lock control device according to characterized in that immediately after switching from individual wheel control to select-low, the first pressure reduction of the non-low channel is throttled or clocked (Fig. Ό. 909826/0401