DE2147816A1 - Blocker regulator - Google Patents

Description

PafenfanwSIfe 2 H 7 8 1 6

° r. Ing.H. Nogendank

D; pl. ! ng. ! - :. Shark

Dipl. Rhys. VV. Schmitz

β Munich 15, .V ^ artstr. 23

Tel. 5 3β 05 8ό

Bendix WEstinghouse Automotive
Air Brake Company

9ol Cleveland Street

2 ';. C - ". Wl

Elyria, Ohio / USA Attorney File M-1752

Blocking regulator

The invention "relates to a pressure medium-operated Brake system, and in particular a blocking regulator for pressure medium-operated brake systems.

Automatic brake regulation is used in conventional pressure-actuated brake systems and is used to prevent the vehicle wheels from locking under variable conditions, such as the wheel load, the tire-road coefficient of friction, μ, and the vehicle speed, by transferring the control to the adapted to various variables and the braking process is optimized. The wheel deceleration is generally measured by such brake control systems, and at a predetermined deceleration value, G. ,, which is close to the slip state, a signal is generated which is a

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The separate relief valve opens and the brake pressure is reduced at a predetermined speed, which means that the wheel can accelerate again. When the wheel acceleration reaches a predetermined value, G ₂ *, a second signal is generated which closes the relief valve so that the brake pressure begins to build up again until the vehicle wheel has decelerated again to the G ^ value, whereupon the Control cycle repeated. This system is hereinafter referred to as the normal control system.

The known control systems work with acceptable reliability and prevent the wheel from locking over a wide range of operating conditions when an optimal brake pressure is adjusted, but under certain unusual conditions, for example when the roadway is unusually slippery or when a vehicle ψ hits a rough road surface an icy bridge comes up, or under other conditions that the above-mentioned normal control system cannot cope with, a very low actuation pressure is sufficient, the vehicle wheels. close to the locked state, and therefore care should be taken to open the vent valve immediately prior to locking the vehicle wheels and regardless of the occurrence of the G ₁ signal. In addition, the vent valve should be kept in the open position longer

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than is normally the case with the Gp signal would be to reduce the pressure to the extent necessary to deal with the aforementioned exceptional road conditions to achieve sufficient wheel acceleration.

To this end, the invention provides the lock controller described in the claims.

According to the invention, a special control mode is provided for a normal G ../ Gp-BIo cki excitation, which at low wheel speeds and a deceleration value that is below the normal G ^ value, determines an impending locking of the vehicle wheel and then opens the relief valve and then disregarding the normal Gp signal keeps the discharge valve in the open position, until the pressure decayed to such that it is ensured that the vehicle has left the impending lock-up condition again "the inventive lock controller responds particularly in unusual road conditions in such a way to _f that it the relief valve holds in the open position for variable periods of time, which are dependent on the length of time that a vehicle wheel needs to reach the acceleration peak after opening the relief valve. Overall, the lock controller according to the invention is thus able to process operating states which

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the conventional regulators are not up to the task. It will also ensured by the blocking controller according to the invention. That the controller in the event of a failure Is switched off for safety reasons.

Further details of the invention emerge from the following description by way of example in connection with the drawings. Show it:

Figure 1 shows the course of the wheel slip as a function of the tire-road friction coefficient μ, for normal or slippery roads,

FIG. 2 shows a graphic representation of the control behavior of the locking controller according to the invention in comparison with the normal G · ../ Gp ~ 'control,

Figure 3 is a schematic representation of the invention usable logic and control levels,

FIG. 4 shows a schematic representation of a pressure-medium-actuated braking device which can be used according to the invention with a pressure modulator.

In the figures and in particular in FIGS. 1 and 2, 10 a typical ^ slip curve for average dry

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Designated road conditions. If the wheels are about to lock on such a road, for example as a result of emergency braking, a brake regulator reduces and increases the brake pressure at points G ... or Gg on opposite sides of the curve maximum 12, as can be seen in particular from curve 14 in FIG «2 can be seen, if a vehicle wheel, which initially runs at a constant speed, approaches an impending slip condition when the brakes are applied, the pressure medium supply is throttled by the normal control at a deceleration value G ^ and a separate relief valve is opened so that the Vehicle wheel can start moving again. When the vehicle wheel has accelerated to the value G ₂ , the relief valve is closed and pressure begins to build up in the brake actuation device, whereby the vehicle wheel accelerates further up to a maximum value at which a wheel deceleration occurs until the G ^ - Value is reached again, after which the work cycle is repeated until the vehicle is brought to a stop »

In Fig. 1, 18 denotes a slip curve for an extremely slippery road surface, and in this case the vehicle wheel can be set at a deceleration value which is smaller than Gj and is referred to below as G _Q (see FIG

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the solid line 19 in Pig. 2) Ms rapidly decelerate to the blocked state without ever _{having passed through the G 1} delay value, and thus the normal control cannot prevent the blocking. According to the invention, to overcome these difficulties, not only one, but two operating parameters of the vehicle wheel are determined, neither of which depends on the G ... Special control mode is referred to, during which the relief valve is opened earlier and kept in the open state longer than would be optimal with a normal dry road in the event of a slip state.

The first measured operating parameter is the wheel deceleration at the mentioned & ₀ value, which, as FIG. 2 shows, is considerably lower than the G ₁ value. The second operating parameter determined is the wheel speed, and if the vehicle wheel has slowed down to a predetermined minimum speed, which is reached shortly before locking, _{i.e. to around 8 km / h, and the G Q} deceleration value is reached at the same time, there is a state before, in which the special control mode begins according to the invention. Then the relief valve is opened, and as shown in curve 19

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of 2 is seen, the vehicle starts after a short time delay increases to accelerate and reaches a G ₂ ~ ^{Who 'fc' is} represented by the dashed horizontal line twentieth However, if the relief valve were to be closed at this point, an impermissibly high pressure could remain trapped in the brake actuation device, and as soon as the pressure was built up again after closing the relief valve, the vehicle wheels would in all probability go into the fully locked state immediately, which means a risk of skidding for the vehicle.

If the lock controller has therefore switched to the special control mode after the occurrence of the combined Cr _o / wheel speed signal, the normal Gp-Si-S ¹¹⁸ I can accordingly be suppressed or delayed so that it does not affect the relief valve according to a further feature of the invention preferably until the vehicle wheel, an acceleration peak has been reached, as indicated by the point _Q _ G_ in FIGS. 1 and 2 is shown, but the delay time could also have a fixed predetermined period of time. At the end of the delay time, a signal is generated that closes the relief valve and triggers the pressure build-up, while the control cycle continues

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repeats like the wheel speed "up to the predetermined speed close to locking
falls and at the same time the G "-y delay value is reached
will.

In Pig.4 a pressure medium brake actuation device 21 is shown which contains a membrane 22 which is attached to its im
In the sense of the figure, the upper side delimits a pressure chamber 24 together with a pressure plate 23, the membrane cooperating on its opposite side with a conventional spring-loaded thrust plate 26. A modulation valve is arranged on the pressure plate 23 of the brake actuation device and has three variable relief cross-sections
contains, each of which corresponds to the particular signal given after the relief valve is closed at point Gp ⁱⁿ
Is generated depending on the remaining wheel acceleration, can be opened selectively,

If the wheel acceleration is up to G., but not
lasts up to the higher value G ₅ (see Fig. 2), the same relief cross-section is opened again that was already opened during the previous control cycle. If, however, the vehicle _{wheel accelerates beyond the higher value G 1} -, the next smaller relief cross-section is opened when the subsequent Gp signal occurs, and

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if the vehicle wheel does not have the G 1 acceleration value reached, a signal is generated that opens the next larger relief cross-section »

In short, if the pressure supplied to the brake actuation device by a brake actuation valve via the supply channel and the inlet 28, 30 applies the brakes so strongly that a slip is imminent, ie the vehicle _{wheel slows down to the G 1} value, a feed solenoid 32 is switched on, which moves a control valve 34 from the switching position shown in the figures into an upper switching position, in which a vent channel 36 is closed and the supply pressure reaches the upper side of a diaphragm valve 38, whereby the valve, which is acted upon by a spring 40 at the same time, is moved adjusted down and shut off the inlet 30, whereupon the supply pressure only reaches the pressure chamber via a throttle opening 41. A solenoid 42 is first switched on by the G ₁ signal, which moves a valve member 44 from an upper switching position, in which it closes a ventilation duct 46, to a lower switching position, in which it closes a supply duct 48, whereupon a relief valve 52 in the closing direction acting pressure is vented in a chamber 50 via the channel 46 to the atmosphere, so that the valve 52 against the force of the spring 54 duroh the over a large

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Ventilation channel 56 attacking brake chamber pressure raised and thereby the brake chamber pressure can be vented to the atmosphere via a vent channel 58. The pressure will thus reduced via the channels 56, 58 and at the same time supplied to the pressure chamber 24 via the throttle opening 41, and there the cross section of the ventilation duct 56 is greater than that of the Throttle opening 41 is, the pressure in the chamber 24 falls with it a predetermined speed until the vehicle wheels have reached the Gp acceleration value, whereupon the Solenoid 42 is switched off so that the control valve 44 returns to the switching position shown in Figure 4 and that As a result, the relief valve is in the closed position,

so that the pressure build-up in the chamber 24 starts again.

As long as the blocking controller works in normal operation and the If the wheel acceleration does not exceed a predetermined upper value, the feed solenoid 32 remains switched on and the diaphragm valve 38 is held in the closed position. Should the vehicle wheel move after the relief valve is closed do not accelerate to the G, value, as shown by point 16 in Fig. 2, a signal is generated by the Logic circuit is generated that causes the blocking controller to use the next larger relief cross-section at the beginning of the next control cycle to open · If, under the conditions mentioned, the vehicle wheel returns to the G value

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delayed, both the solenoid 42 and the second solenoid 60 are turned on which actuates a valve 62, which is lowered from the switching position shown in Pig. 4 and thereby a ventilation duct 66 with a chamber 64 connects and at the same time separates this chamber from a duct 67 leading into the pressure chamber 24, whereby the second membrane relief valve 70 by the pressure in one Vent channel 68 can move small flow cross-section into the open position. Therefore, if the two solenoids are switched on, the pressure in the pressure chamber 24 is both through the ventilation channel 56 large flow area as well as reduced through the vent channel 68 small flow area to the atmosphere, both Vent channels together form a relief cross-section that is larger than that which was during the previous one Control cycle was open.

If the special control mode of the lock controller according to the invention controls the brake actuation device in the manner described above, the road surface is such that a vehicle _{wheel will most likely not reach the G 4} acceleration value, and therefore the next larger relief cross section is opened at the beginning of the control cycle following an initial cycle, which is represented by both vent channels 56,58, ie the

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maximum relief cross-section, and this process is repeated as long as the lock controller is in special control mode, the logic and control circuits that are required to control the variable relief cross-sections depending on the G ^ - and Gr acceleration value, not for understanding the invention are absolutely necessary and in the subsequent casually loading W wrote "

With reference to Pig 3, if a vehicle wheel hits a road surface on which it slows down to near locking speed when the brake is applied, this fact is detected by a wheel speed counter 78 and transmitted to a wheel speed comparator 80 which produces a positive output when that of The signal received by the counter indicates a state that is close to the wheel lock speed, i.e. about 8 km / h. This wheel speed signal is fed to one input of an AND gate 82, the other input of _{which is supplied by a G 0} comparator 84 which is responsive to a G _Q signal, a differentiator 86 being used to generate this signal, which is connected to the output of the Counter 78 is connected and constructed in such a way that it generates an output voltage proportional to the wheel acceleration ₅ . So there is a GQ signal and an 8 km / h signal at the inputs

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of the corresponding comparators are pending, "the output signals of which bring the two inputs of the AND gate 82 into the positive state and the AND gate outputs a signal to the switching input of a flip-flop 90 and to one input of an OR gate 88, which with its output at the switching input of a second flip-flop 92 is applied »If both flip-flops are switched, their outputs are positive, the output signal of the flip-flop 92 is fed to the input of a control output stage 93, which responds to this signal as whether it would have received a signal representing wheel deceleration at the above mentioned G ₁ value.

If the vehicle wheel was not exposed to the severe operating conditions that lead to the simultaneous occurrence of the Gß / wheel speed signals just described, but the braking force was nevertheless too great for the existing conditions, so that slipping is imminent, a G ₁ comparator 95 triggers the Normal regulation of the braking process off when the vehicle _{wheel slows down to the normal G 1} value · As can be seen, the input of the G ₁ comparator 95 is on. connected to the output of the differentiator 86, and if the output signal of the differentiator 86 _{exceeds the reference value of the G 1} -! Comparator, a signal is generated at the output of the Gj comparator that the switching input

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of the aforementioned flip-flop 92 via one input of an AND gate 96 (the second input of which is normally positive, as will be explained below) and the second input of the OR gate 88 is supplied. 3) The slip-flop 92 is thus switched on either by a combined & _Q / 8 ifcm / h signal, ie by an apparent GK signal, or by an actual G signal, the response behavior being the Tax issuing level is identical in both cases.

The control output stage is activated by the signal from a brake switch brought into the operational state, this signal arises when a brake switch 97 is closed, which generates a positive signal that is converted in an inverter 98 into a zero signal at one input of an OR gate 99 is converted, which continues with its exit to several years

»Components described below are connected, among which is the input of an inverter 100, which leads to the control output stage 93, whereby the jam output stage is switched into the operational state when the brake switch is closed when the brake pedal is pressed will.

When an apparent or actual signal arrives at the control output stage, a signal becomes a

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Main exhaust amplifier 101, which is the solenoid 42 "actuated, whereby the brake pressure chamber 24 through the the channel 56 formed middle relief cross-section is vented to the atmosphere, as described above was · The vehicle wheel now begins to accelerate and finally reaches the Gg value (Fig, 2), and if the Brakes are regulated by the normal control, the relief valve is activated at this point as a result of a signal which is generated by the Gp comparator 102, the input of which is connected to the differentiator 86 and its output in the absence of the special control system provided according to the invention directly with the downshift input of the flip-flop 92 would be connected so that the output signal of the flip-flop 92 is cleared and the solenoid 42 as shown in FIG would be de-energized to close the relief valve and via the throttle opening 41 in the brake actuator to trigger a slow build-up of pressure again. However, during special regular operation it is necessary to to keep the relief valve in the open position longer than would be achieved with normal Gg-SiSHaL, and for this purpose the normal Gp signal is suppressed or for one beyond the Gp value of the wheel acceleration length of time is delayed, and although this delay time according to the invention can have a fixed predetermined length, it is preferably variable and depends on the time

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duration from the vehicle wheel to reach the maximum Acceleration required after opening the relief valve, and because the time required to achieve maximum acceleration varies during a braking process under consideration changes according to the road condition, the lock controller according to the invention adapts to the variable above-mentioned Conditions by changing the delay time to the * maximum wheel acceleration instead of a fixed one Time period is related.

The output of the Gp comparator 102 is connected to one input of an AND gate 104, the output of which is connected to one input of a multiple OR gate 106, the output of which leads to the switch-back inputs of the flip-flops 92, 90 Therefore, when the Gp reference value of the wheel acceleration is reached, the G ₂ ~ comparator generates a signal, but if a zero signal is present at the second input of the AND gate 104, as is normally the case in special control mode, as described below is explained, this Gr2 signal has no effect.

If the flip-flop 90 is turned on when the Gq and wheel speed signals occur simultaneously, the positive output signal of the flip-flop 90 is fed to one input of an OR gate 108, the output of which

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signal in turn the shutdown input 109 of a clock timer 110 is supplied, the puncture of which is described below "and of which only explained at this point let that the special control signal in the special control mode turns off the clock, so that he during the Special control mode has no effect.

The output signal of the flip-flop 90 is also fed to one input of an AND gate 112, the other input of which is connected via an inverter 114- to the output of a peak value detector 116, the input of which is connected to the output of the differentiator 86. The peak value detector is constructed in such a way that it only generates a signal at its output when the differentiator emits an output signal which represents an acceleration maximum of the vehicle wheel, ie GL _8x according to FIG. 2. At all other times there is a zero signal at the output of the peak value detector, which is converted into a positive signal in an inverter 114- and fed to the second input of the AND gate 112, so that when the flip-flop 90 is switched on, it is triggered positive signal at the first input of the AND gate 112, the output of the AND gate 112 becomes positive, but this signal is converted into a zero signal by an inverter 118 and fed to the second input of the AND gate 104, at its output

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a zero signal is present, so that the signal fed to the OR gate 106 is also zero, and since the two other inputs of the OR gate are also zero in this state, no signal is fed to the switch-back inputs of the flip-flops 92, 90. In short, as long as the output of the peak value detector 116 is at zero and the flip-flop 90 is switched on by a combined G _Q / 8 km / h wheel speed signal, no signal from the Gp comparator 102 via the AND gate 104 reach the reset input of the flip-flop 92, so that a signal remains at its output and the relief solenoids remain in the switched-on state.

However, if the blocking controller is not in the special control mode, the flip-flops 90, 92 are automatic switched back by the positive signal generated when the brake switch is opened, this signal denoting Switch-back inputs of the flip-flops via a second input of the OR gate 106 is supplied. If the output of the flip-flop 90 is now at zero, one is Input of AND gate 112 to zero, so that its output signal must also be full, this output signal is converted by the inverter 118 into a positive signal, which is at the lower input of the AND gate 104 pending. Therefore, if the special control mode is not activated

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is switched, the lower input of the AND gate 104 is always positive, and every time a normal Gp signal is present at its other input, a positive signal is generated at the output of the AND gate 104 and the reset input of the flip-flop fed 92 so that the vent ^valve is closed at a ~ ^e S Gg acceleration value as if the lock controller would be constructed without the possibility of special control operation.

In summary, it can be said that, if during of the special control mode, a Gp signal at the output of the Gg comparator 102 is pending, this signal remains as long as the wheel acceleration is at or above the Gg value. However, this signal does not affect the lock controller until the vehicle wheel reaches maximum acceleration whereupon the peak detector 116 has a positive Signal generated that enables the Gp signal to continue to the reset inputs of the flip-flops 92,90 to to close the relief valve and at the same time to set a zero signal at the upper input of the UHD gate 112, thereby ensuring that a positive signal is present at the lower input of AND gate 104, so that the Blocking regulator for the normal regulation, in which he is on the responds to the usual G .. and Gg signals, is prepared, if the tire-road conditions improve in such a way that the special control mode is no longer appropriate

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Regarding the clock timer 110, it can be seen that its normal input 119 connected to the output of & ^ comparator 95 via the lower input of AND gate 96 is. The upper input of the AND gate 96 is connected to the output of the timer 110 via an inverter 120 which has the converts the normal zero output signal of the timer to a positive signal, whereby the AND gate 96 normal-

at

wise is in a switching state / which it _{forwards a signal generated when a G 1} signal occurs to the flip-flop and triggers a brake control process. Should a G .. signal not be present at the normal input 119 of the timer 110 after the last Gj signal has been generated within the switching time of the timer, which can be one second, the output signal of the timer becomes positive and this positive signal becomes a Zero signal at the upper input of the AND gate 96 converted so that the AND gate 96 goes into the non-conductive state, and as soon as this happens, all of the following G .. signals are not only from the flip-flop 92, but also kept away from the input 119 of the timer, so that it continuously generates a positive signal during the braking process in question *

In addition to the fact that the transmission of the G ^ signal is blocked is, as has just been described, a positive signal at the output of the timer is one input of a

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OR gate 128 and also fed to a differentiator 130, which in response to a positive input signal a pulsating output signal is generated which is fed to the OR gate 106 and from there to the downshift inputs the flip-ίΊops 92.90 gets to the signal from the output of the flip-flop 92 to the control output stage 93 delete and thereby cause the relief valve to close. By switching back the flip-flop 90 is ensures that a switch-off signal at input 109 of the Clock timer is cleared, and at the same time the upper input of AND gate 112 is set to zero.

The output of OR gate 128 becomes the downshift input a flip-flop 132, the output of which is connected to one input of an AND gate 134 whose output is connected to the power amplifier 136 for the supply valve. The other input of the AND gate 134 is connected via an inverter 137 to the output of a G, comparator 138, which is only in one exceptionally high value of the wheel acceleration responds before it generates an output signal that has the purpose that To open the feed valve and to allow a rapid pressure build-up of the brake chamber pressure. The output signal of the However, G -, -! Comparators 138 is normally set to zero and becomes a positive signal through an inverter 137

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converted and fed to the upper input of the UKD-ßatters 154, so that AND gate 134 becomes conductive and thereby causes the feed valve to close when the flip-flop 132 is in the on state.

The switch-on input of the flip-flop 132 is at the output of the flip-flop 92, so that, if the flip-flop 92 is so

™ is set that it connects a signal to the control output stage 93, and an opening of the relief valve is effected, at the same time a signal reaches the switching input of the flip-flop 132, which leads to a closing of the feed valve. If the signal in the supply line of the control output stage is ^{canceled in the manner described above by the normal GP-Siß 11} ^, this has no influence on the switched-on state of the flip-flop 132, which remains in the switched-on position and thereby the feed valve

ψ holds closed until a signal arrives at the jerk-hold input of the clock timer 110, whereby the feed valve is opened simultaneously with the closing of the relief valves, so that the braking process now returns to an operating mode in which the control takes place solely through the action of the operator on the brake pedal .

In addition to the fact that the flip-flop 132 by a signal from Clock timer is switched back, it is also through

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reset a second signal from OR gate 128 which is generated when the brake switch is opened, as described above.

If the normal control has been switched off by the clock timer in the manner just described, for the Case that the vehicle encounters extremely slippery road conditions during the shutdown period, so that a combined Gq / wheel speed signal is generated by the flip-flops 90.92 switched on by this signal regardless of the clock timer, whereby the previous switch-back signal, which occurred due to the actuation of the clock timer was only chopped up by the differentiator 130, so that none Signal at the reset input of the flip-flops is no longer present. By this independent switching on of the flip-flops 90, 92 becomes a signal from the flip-flop 92 to the control output stage 93 through-fc, so that the special control mode is triggered is, and further a signal is output by the flip-flop 90 to the shutdown input 109 of the clock timer 110, so that the positive signal present at its output is canceled and the timer has no influence when the blocking controller works in special control mode (if the brake switch is opened again, a positive signal is sent via the Inverter 98 and OR gates 99,108 to shutdown input 109 of the clock timer to ensure that this is switched off when the brakes are not applied)

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In addition to the temporary switching off of the normal control by the clock timer (but not the special control mode, as has been explained), the switching off of all automatic control modes is made possible by a second timer 140, which is referred to below as the shutdown timer. The output of the switch-off timer 140 is normally at zero and remains at zero as long as a signal fed to its input is cleared within a predetermined relatively long period of time, for example within four seconds. The input of the switch-off timer is connected to the output of the flip-flop 92, so that if the flip-flop 92 transmits a signal to the control output stage that opens the relief valve, this signal also reaches the input of the switch-off timer and triggers a clock pulse. Should this signal for any reason, such as a fault in the controller, not be _{deleted by a G 2} - or ^ m _3x ^- SiS ¹¹³¹ within the cycle time of the switch-off timer, so that the relief valve remains in the open position too long, the The output of the timer is positive and the signal is fed to the OR gate 99 and from there to the switch-back input of the flip-flops 90, 92 and 132 and the switch-off input 109 of the clock timer 110. In addition, a positive signal reaches the input of the inverter 100, which is applied to the control output stage, so that the output signal of the

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Inverter becomes zero and therefore the control output stage does not remains in the "operational state" longer as long as the inverter 100 receives a positive signal either from the shutdown timer or following an opening of the brake switch.

TJm to ensure that the controller is not switched on again by any device that can be influenced by the operator can be, a shutdown memory 142 is provided according to the invention, which is triggered by a positive output signal of the switch-off timer is actuated, and this memory can switch the controller off continuously until it closes can be dismantled at a later point in time in order to determine the exact reason for the operating irregularity »On the other hand the memory can also only use the automatic control for the duration of the particular braking process in which the Operating irregularity occurs, switch off «

The mode of operation of the controller according to the invention should emerge from the above description. If the controller is operating in normal control, a signal supplied by the differentiator 86 at the G ₁ value opens the relief valve, which reduces the brake pressure, while the relief valves are closed when the wheel accelerates at & 2 "* ^{¥ θΓ} ^ «This is made possible by the

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Output signals of the G * and Go comparators reached the act on the switching and switching back inputs of the flip-flop 92. If desired, the relief cross-section can be changed depending on the wheel acceleration remaining after the relief valves have been closed, i.e., if the pressure reduction was too great and consequently the wheel acceleration was too great, a Gc comparator 146 a store signal to a relief stage 148 released, whereby the next smaller relief cross-section is opened at the beginning of the next control cycle; if however the wheel accelerates to the optimum value G. speaks a G * comparator 150, with the result that the same Relief cross-section is kept free as in the last control cycle; if the G, value is not reached (insufficient Relief), the controller ensures that the next largest relief cross-section in the next control cycle is opened «

In the event that a vehicle encounters an unusually slippery section of road before or while the automatic brake control mode is switched on, so that a combined GQ / wheel speed signal is generated, G _{0 will be} at a considerably lower deceleration value than υ. is, the regulator opens the relief valve earlier than in normal control, and there a

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relatively high residual pressure may have been trapped in the brake pressure chamber ₉ as the last normal G - signal was obtained, will now be locked during the special control mode, the normal G2 "" ^si 6 ^na lf ^for a period of time may have a fixed length of time, but preferably is variable and adapted to the existing operating conditions, as given by the time it takes a vehicle wheel to reach the maximum acceleration after the pressure reduction triggered by the opening of the relief valve, which, as shown in Fig. 2, is considerably later than the wandering In view of the existing and probably constantly fluctuating road conditions, the vehicle wheel will certainly accelerate to such an extent that it will not lock immediately when the pressure is restored following the closing of the pressure valve. The peak detector 116 determines the maximum of the wheel acceleration transmitted by the differentiator 86 and generates a signal that allows the switching through of the already generated Gg signal to the switch-back inputs of the flip-flops 92.90, which leads to the closing of the relief valves, and as long as during the subsequent control cycles the Gg / wheel speed signal is generated, the controller repeats the special control cycle until the vehicle stops or gets onto a better roadway in which

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a wheel speed signal equal to the reference value of the wheel speed comparator 80 is not reached so that the controller returns to normal control mode, as described above »

According to the invention, a clock timer may be further provided which switches off the normal control mode during a single ψ braking operation, when the consecutive G are not produced ₁ signals within the cycle time of the timer, wherein the timer is turned off, if the controller switches over to the special control mode, Further, a second timer can be provided which switches off the entire controller permanently or temporarily if a fault occurs as a result of a serious operating irregularity, as described above.

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Claims (1)

Attorney File M-1752 Claims 1 · Locking regulator for a pressure fluid operated brake system \ - / to regulate the brake actuation "when slipping of the vehicle wheel, with a, first signal level, which at a predetermined value of the linear wheel speed generates a first signal, a second signal stage which a second for a given value of the wheel deceleration Signal generated, a third signal stage, which at a predetermined value of the wheel acceleration a third Signal generated, a timer for generating a timer signal, a pressure reducer to reduce the Fluid pressure in the brake system and one through the third signal actuated the pressure booster to rebuild the fluid pressure in the brake system, characterized by a fourth signal stage (82) for Generation of a fourth signal with simultaneous recording -30- 209816/1025 ' the first and second signals occur, the timer (140) and the pressure reducer being activated by the fourth signal can be switched on. 2 · blocking regulator according to claim 1, characterized by a fifth signal stage (110) for generating a fifth signal at the end of a time segment triggered by a switching stage (90, 108) responsive to the fourth signal w , the pressure booster being able to be switched on by the fifth signal. 3. Locking regulator according to claim 2, characterized by a control stage (116) which is set to the maximum with the pressure reduction triggered by the fourth signal achieved wheel acceleration responds and defines the end of the time segment * 4. Locking regulator according to claim 2, characterized by a second signal stage (95) which, at a predetermined value of the wheel deceleration which is above the first deceleration value, generates a sixth signal by which the timer and the pressure reducer can be switched on, and one to the fourth signal responsive. Locking stage (104) »which prevents the fluid pressure from building up again at the specified value of the wheel acceleration by means of the third signal · 209815/1026 " ³¹ " 5. Locking regulator according to claim 4, characterized by a control stage (116) which is based on the maximum wheel acceleration responds and enables the actuation of the pressure booster by means of the third signal. 6. Locking regulator according to claim 5, characterized by a further locking stage, which in the presence of the responds to the sixth signal and the generation of the timer signal by the timer (140) for a predetermined, prevents the period following the generation of the sixth signal, and a control stage which to the one generated by the timer (140) in the absence of the sixth signal within the predetermined period of time Timer signal responds and switching on the pressure reducer or pressure booster by the sixth or third signal prevented. 7 · Blocking regulator according to claim 6, characterized by a switching stage for the fourth signal responsive to the Switching off the timer (140) and a control stage (H 6) for switching the timer on again, which is based on the maximum responsive to the pressure reduction triggered by the fourth signal following wheel acceleration. 209815/1025 8. lock controller according to claim 6, characterized by a switch actuated by the Power-down timer signal (142) that is constantly a pressure reduction or _e prevents repressurization by the fourth and sixth signal and the third signal. 209815 / 102S