DE2050328C3 - Arrangement of an anti-skid device for vehicle wheels, in particular for road vehicles - Google Patents

Description

the first control signal and after holding time (T ₁ ) chen by the second - switched control signal - formed by the wheel decelerator.

2. Arrangement according to claim 2, characterized in that when the time of the damping of the wheel deceleration sensor (16a) is running, the brake pressure control valve device (13 ″) causes a brake pressure reduction in the second by the control signal emitted by the _{wheel deceleration sensor (16a) before the end of the certain holding time (T 1)} Switch position is switchable.

3. Arrangement according to claim 1 or 2, characterized in that each vehicle wheel has a speed comparison device 15 ", 15 b, 15 c, 15 d), a wheel deceleration sensor (16", 16b, 16c, Ud) and a brake pressure control valve device (13u, 13b, 13c, 13d) assigned «u where the wheel speed signal is assigned to the corresponding wheel trains, electronic device known per se (3e ,, 36, 3c, 3d) and the vehicle speed signal is assigned to all wheels, also per se known electronic device (5 for deriving one of the vehicle speed

corresponding reference signal from the wheel speed of all wheels, formed w, approx.

^^ _the ßremsdrucksteuerven- ^ in the sense of a reduction of the _veru rsacht. But since the not directly

^ _{and therefore theS} em mostly not always

™ ^ ^g ^ is _{running up} , such anti-skid analogs are reported ^

45

50

55 (OSί 19
digkert

“^^ to stabilize, that is, to 'fc _{as a result of the between}

_{d de} f _Tatsäc hlichen Fahrzeugge- ^ eüig deviations occurring is the use of Radverzoge- "Jerlich which delay the reference value in the absence _'e f of the wheel assembly are korrigiebekannten a sliding _{of the} genus ^ Verzögerungsf the driven gears associated with" a SeTwird from the speed- _{"from eleite} th reference signal when _{b <J timmten} delay this fiB ,! _An-other known anti-skid device of the genus ^ b to affect the course of the subsequently

submitted ^^ | ^

To flüssen (OS "JJ" ³ ) 'Correction of the reference variable analogous to Fahr-J ^ SuSgS ^, it is necessary that ^ e deceleration transmitter used is very weakly damped, ie very slightly

are responsive. However, such delay donors are particularly complicated and therefore very kost- 'Α

etae

the braking force of rotation deceleration signals, the supported by a speed difference signal.

With this arrangement, the delay signal - b experiences a delay similar to attenuation (FR-PS 15 92 594, DT-OS 16 55 454).

A complex signal generator is also required with this arrangement of an anti-skid device.

The invention is based on the object of avoiding this disadvantage and an arrangement of a To create anti-skid device of the type mentioned, which is relatively easier to use and thus cheaper electronic means one that corresponds exactly to the respective circumstances Control of the brake pressure in terms of a reduction in slip guaranteed.

This object is achieved according to the invention by the combination of the features:

a) the wheel deceleration sensor (16 a) has - like " known for itself - a strong attenuation on;

b) the valve device (13 a) is first activated by the first control signal and after the hold time (2 \) through the second - from the wheel deceleration »5 Encoder formed - control signal switched.

It is advantageous if the dependent on the damping of the wheel decelerator when the expires Time before the end of the certain holding time, the brake pressure control valve device by the wheel decelerator output control signal in the second switching position causing a brake pressure reduction is switchable.

To adjust the brake pressure on each individual wheel according to the conditions prevailing on it control and thereby simplify the entire anti-skid system of the vehicle is also according to the invention provided that each vehicle wheel has a speed comparison device, a wheel decelerator and a brake pressure control valve device is assigned, wherein the wheel speed signal by a known electronic device assigned to the corresponding wheel and the vehicle speed signal through a signal common to all wheels, also known per se electronic device for deriving a reference signal corresponding to the vehicle speed is formed from the wheel speed of all wheels.

The inventive arrangement of an anti-skid device is based on the knowledge that heavily damped electronic deceleration and acceleration sensors are structurally simpler and therefore much cheaper than weakly damped sensors, the strong damping leading to a strongly delayed output of the corresponding -b- or +6 signal but does not affect the instantaneous fall of the signal. Under heavily damped deceleration and acceleration sensors are to be understood in principle sensors whose damping is set so that there is a speed bounce on the controlled wheel, which is 1.5 to 3.5 kim / h greater than with conventional encoders, which in the Usually show a speed drop of 1.5 to 3 km / h . The drop in speed occurs in the time from exceeding the response wave to the delivery of the signal. Ultimately, however , the decisive factor is a damping value that prohibits the use of the encoder in the known anti-skid device arrangements of the type, which are subject to high requirements in terms of operational safety and the utilization of the braking force of the wheels in all operating states.

The use of such heavily damped deceleration and acceleration sensors in such arrangements of anti-skid devices is made possible according to the invention in that the brake pressure is first applied without delay as a function of a J _v signal emitted by the speed comparison device (ISo) and only after a signal from the damping of the sensor and Time dependent on the respective wheel speed is controlled by a - b-signal emitted by the encoder. This eliminates the disadvantageous effect of the strong damping and, on the other hand, stabilizes the anti-skid device arrangement in the area of the brake pressure reduction even with a relatively low response threshold of the speed comparison device. The latter has the advantage that after initiating braking, the increase in brake pressure is interrupted when a relatively small slip is reached, whereby z. B. the compressed air consumption in compressed air braking systems is lower. The brake pressure curve following the interruption of the increase in brake pressure according to the invention ensures good utilization of the braking force absorption capacity of the wheel as a function of the respective road condition and a soft brake pressure regulation.

Through the use of heavily damped wheel accelerators can be both a response of the sender in the braking phase, in the high wheel decelerations occur, as well as an incorrect response of the encoder caused by vibrations on the wheel be avoided. In addition, the number of poles of the generators can be reduced or it can simple signal generators with a small number of teeth can be used.

The use of decelerators to control the brake pressure in the last brake pressure reduction range also offers the possibility of maintaining a residual pressure when the - b signal drops, without impairing the anti-skid function of the facility.

Since the renewed rise in pressure is made dependent on the instantaneous fall of the + b signal, which is not influenced by the strong damping, and not on the fall of the <d _v signal, which usually differs in time from the actual fall below the critical slip, the arrangement according to the invention is a Anti-skid device stable even when the bike starts up again.

Another advantage is that the inventive arrangement of the anti-skid device in the event of failure the speed comparison device or the deceleration and acceleration sensor the encoder or the speed comparison device (15 α) remains functional to a limited extent, so that the entire arrangement does not fail completely.

In the following an embodiment of the invention is sewn with reference to the drawing explained. It shows

F i g. 1 is a schematic block diagram of an anti-skid system, which consists of four inventive arrangements of anti-skid devices

5 6

a common device for generating a chip supplied by the converters 3a, 3b, 3c, 3d

corresponding to the vehicle speed reference is present, so that only the speed of the

signals, each faster and therefore less prone to sliding

F i g. 2 a logic circuit for the arrangement of the wheel is decisive for the formation of the vehicle's anti-skid device according to FIG. 1, symbolic 5-speed analog reference voltage. shown in the table, The response threshold of the speed

F i g. 3 a time-pressure-speeds-Dia- equaling device 15 a is chosen so low that the

gram for the arrangement of the anti-skid device device 15 a already sends a control signal A _v

measured the Fig. 1 and 2. Achievement of a relatively very small difference

As can be seen from FIG. 1 of the drawing, the slide protection system shown relates between the vehicle speed entich to a four-way reference voltage and that of the wheel-wheel vehicle, each wheel emitting a voltage corresponding to the invention, according to the arrangement of an anti-skid device la, the generator 2a, the converter 3a, the differential Ib, lc, is assigned ID in the following, the renzierglied Sa, the damping members 7a, 8a and the right front wheel FW associated assembly 15, the trigger 9 a, 10 a to form an electronic cycling Ia described in more detail. The deceleration and acceleration sensors 16 a of the ordered arrangements Ib, lc, Id assigned to the remaining wheels are designed to be identically strong and therefore relatively sluggish. and when a threshold is reached, display the sliding threshold

The anti-skid device la has the wheel deceleration and one restart Order a wheel acceleration which is driven by the vehicle wheel and indicates the wheel acceleration

nerator 2 a for generating electromagnetic control signal - b or + b with one of the damping

Impulses, the frequency of which is a measure of the exercise and the respective wheel speed.

speed of the wheel, it also emits a frequency-gigen deceleration. The -b- or + b-

Voltage converter 3 a, which converts these pulses into signals are also the logic circuit 12 a

converts proportional voltage, one fed to the 35.

Converter 3a in operative connection via diode 4a. The logic circuit 12a is in accordance with FIG. 2

standing signal converter 5 for generating a from a first timing element 17 with dynamic input

Reference voltage that went to the vehicle speed 18,19, a second timer 20 with two

at maximum permissible deceleration of the vehicle dynamic inputs 21, 22 and a third as

is analogous, a differentiating element 6 a to the differential 30 signal delay element formed timing element 23.

decorate the voltage output by the converter 3 a, an input signal is at the inputs 18 and 21

Attenuators 7a and 8a for the differentiating- only at the transition from 0 to 1 and at the input

member 6 a, a trigger 9 a for releasing a gear 19 and 22 only when changing from 1 to 0

—Ft signal becomes ineffective when one of the value —b is reached . The timers 17 and 20 supply so long

speaking wheel deceleration, a trigger 10 a 35 an output signal until its hold time Z ₁ or Z ₂

for issuing a +6 signal when one has expired or at its inputs 19 or 22

an input signal becomes effective for the wheel acceleration corresponding to the value + b. The timer 23

and one, for example, as a differential trigger delivers a value compared to the input signal

formed comparator 11 α for comparing the delayed by a certain delay time T ₁

Signal converter 5 and from converter 3 a 40 output signal until the input signal is deleted,

These voltages, which are generated by the speed comparison device via a logic circuit Das

12 a with a brake pressure control valve 13 a in active 15 a output ^ signal is the input 18 of the

connected. first timing element 17 and the input of the third

The generator 2 a, the converter 3 a, which is fed to the four timing element 23 The wheel deceleration arrangements of anti-skid devices la, Ib, 45 and wheel acceleration sensor 16a output - b-Ic, Id common signal converter 5 and the Ver signal is at the input 21 of the second time equalizer 11a form an electronic speed member 20 and the negated input of an AND-keitsvergleichseinrichtung 15a, which is one of the driving - Tores 24 on. The +6 signal is fed to the input 19 generating speed corresponding reference variable derived from the wheel of the first timing element 17 and the input 22 of the speed with a second timing element 20 equals and when a certain difference is reached OR gate 25 and via an AND gate 26, at whose between the two variables (response threshold) a negated input emits the control signal output by the timing element 23, which is the output signal of the logic circuit 12a, an OR gate 27 is supplied. 55 leads The output signal of the timer 20 becomes

The signal converter 5 is supplied to the OR gates 25 and 27 in a known manner

principally from a resistor-capacitor circuit The anti-skid device la has in its

device (ÄC element) and emits an output signal, order a brake valve designed as a directional control valve

its initial value from the value of the signal pressure control valve 13, which is shown in FIG. 2 in a Mnformer 5 pending input signal depends 60 from a compressed air tank 31 to a

and its further course of the discharge curve of the brake cylinder 32 acting on the right front wheel FR

The condenser roughly corresponds to The course of the leading line 33,34,35 is arranged Dem The output signal can be input in a known manner. Brake pressure control valve 13 is a brake valve 36

be provided that the signal voltage of the vehicle upstream two solenoid valves 37, 37 'are used speed at maximum permissible deceleration 65 for switching the brake pressure control valve 13 into a

of the vehicle is analogue With the help of the four diodes of the three switch positions shown below. 4a, Ab, Ac, Ad it is achieved that at the signal- If both solenoid valves 37,37 'are de-energized, only the highest of the four is then the brake pressure control valve 13 in a converter 5

a switching position causing a brake pressure increase in which, if the brake valve 36 is open, the Brake cylinder 32 is connected to the compressed air tank 31. If both solenoid valves 37, 37 'are excited, the brake pressure control valve 13 is then in a position which causes the brake pressure to be kept constant Switching position in which the brake cylinder 32 both from the atmosphere and from the compressed air tank 31 is separated. If the solenoid valve 37 is energized, but the solenoid valve 37 'is de-energized, so is then the brake pressure control valve 13 in a brake pressure reduction causing Switching position in which the brake cylinder 32 is connected to the atmosphere. The solenoid valves 37 and 37 'are controlled by the signals emitted by the OR gate 25 and the AND gate 24, respectively.

The mode of operation of the arrangement according to the invention according to FIGS. 1 and 2 will be explained below with reference to the diagram according to FIG. 3, where V _{P is} the time profile of the vehicle speed, V _{R is} the time profile of the wheel speed, Vf is the time profile of the pseudo vehicle speed, which is formed by the reference voltage output by the signal converter S, and P _{B is} the time profile of the VR on the right front wheel represents effective brake pressure.

The generator 2a driven by the right front wheel VR continuously supplies pulses, the frequency of which is a measure of the speed of the wheel. The converter 3 a converts these voltage pulses into a voltage corresponding to the wheel speed, which is supplied on the one hand to the comparator 11 ', on the other hand via the diode 4 a to the signal converter 5 and finally also to the differentiating element 6 a. The signal converter 5 supplies a reference voltage that is dependent on the largest of the voltages supplied by the four converters 3 a, 3 b, 3 c, 3d, which represents a reference value analogous to the vehicle speed and the so-called pseudo vehicle speed and is also fed to the comparator 11 α.

The differentiating element 6 a differentiates the signal supplied by the converter 5 and emits an output signal corresponding to the respective deceleration or acceleration of the wheel, which is damped by the strongly damping attenuators 7 a, 8 a and by the trigger 9 a, 10 a when the corresponding sliding or restart threshold is converted into a constant - b or + fc signal.

When the brake is not actuated, the brake pressure control valve 13 is in the switching position shown in FIG. 2. If a braking process is triggered by actuating the brake valve 36, the compressed air tank 31 is connected to the brake cylinder 32 via lines 33, 34, brake pressure control valve 13 and line 35 and a brake pressure increasing according to the curve Pb ₀ -Pb ι is applied in the latter.

It is assumed that when the effective brake pressure P _Bi (time J ₁ ) is reached, the wheel speed V _R has decreased compared to the pseudo vehicle speed Vψ to such an extent that the response threshold of the speed comparison device 15 α is exceeded, so that it emits a ^ v 'signal This response threshold is selected to be so small that the device _{ensures that a J v} signal is output as soon as the critical slip is reached.

The J _v signal is fed to the first timing element 17 on the one hand, and to the third timing element 23 on the other hand, so that both timing elements become effective without delay. The output signal emitted by the timer 17 energizes the solenoid valve 37 via the OR gate 25 and the OR gate 27 via the AND gate 26 into the AND gate 24, the solenoid valve 37 ', so that the brake pressure control valve 13 keeps the brake pressure constant effecting switch position is switched.

After the delay time T ₁ given by the third timing element 23 has elapsed (time < ₂ ), the dy signal present at the timing element 23 becomes effective at the negated input of the AND gate 26, whereby the output signal emitted by this is deleted. This also clears the signals emitted by the OR gate 27 and the AND gate 24. The solenoid valve 37 'is de-energized and the brake pressure control valve 13 is switched to its switching position causing a brake pressure reduction.

It is now assumed that when the brake pressure P _{ß3 is reached} (point in time t ₃ ), a - i> signal emitted by the wheel decelerator 16 a becomes effective on the timing element 20. As a result, the latter emits an output signal which superimposes the output signal of the timing element 17 in the OR gate 25 and causes the solenoid valve 37 to remain energized as long as the - b signal is effective. The - b signal also has the effect that the negated input of the AND gate 24 is also deleted, so that the solenoid valve 37 'remains de-energized.

The brake pressure control valve 13 thus remains in its switching position which brings about a brake pressure reduction _{even after the point in time J 3.} However, what is decisive for the extent of the further reduction in brake pressure is no longer the / ly signal output by the speed comparison device 15 a, but the ft signal output by the wheel deceleration sensor 16 a. If the wheel deceleration has decreased as a result of the brake pressure reduction to such an extent that the - fa signal is deleted (time / ₄ ), then the solenoid valve 37 'is re-energized by the timer 20, while the solenoid valve 37 also remains energized by the timer 20. As a result, the brake pressure control valve 13 is switched back to its switching position which causes the brake pressure to be kept constant.

If the - fe signal is, for example, due to a deterioration in the road conditions before the expiry of the delay time T ₁ , e.g. B. at time point t, ' effective, the deletion of the dei at the negated input of the AND gate 24 causes the immediate de-excitation of the solenoid valve 37' and thus there immediate switching of the brake pressure control valve 1; in its switching position causing a brake pressure reduction. The predetermined by the timer 23! Delay time T ₁ is so dimensioned that the time point at which a -ft signal is effective to be good road conditions delay time shortly after the Ver T _1, in bad road condition as to shortly before the expiry of the delay time T ₁ Liegi

It is now assumed that at Zeil point f _{5 of} the wheel acceleration sensor 16 a during the restart of the wheel emits an -ffe signal that the inputs 19 and 22 of the timers 17 and 17, respectively

509646/14

20 is supplied. Due to the design of these inputs described at the beginning, however, the timing elements 17 and 20 are only deleted when the + b signal drops out again after the wheel has restarted (time / ₇ ). The deletion of the two timing elements 17 and 20 and thus the de-excitation of the two solenoid valves 37, 37 'as well as the subsequent switching of the brake pressure control valve 13 o into a switching position causing a renewed increase in the brake pressure corresponding to the initial position it assumed at time t ₀ thus depends, according to the invention, on the drop of the + b signal and not the J _v signal. The stop characters Z ₁ and Z ₂ are chosen so that they only expire after the fall of the + fe signal. So they are used for

10

Store the - fc signal until it goes through the drop of a + i> signal can be deleted.

The elements shown symbolically in the drawings 1 and 2 are, for example, from the Catalog "Integrated Digital Circuits in TTL" from Texas Instruments, May 1970 edition, known and therefore not described in more detail.

In the arrangement described above, an anti-skid device becomes that of the vehicle

ίο speed corresponding reference value from a; derives the corresponding size of the wheel speed. However, it is possible within the scope of the invention Hch, the reference variable from other variables related to the vehicle speed, wii

z. B. derived from the deceleration of the wheel.

For this purpose 3 sheets of drawings

Claims (1)

Patent claims: 1 Arrangement of an anti-skid device for Families, especially of road vehicles «St thnem from the monitored vehicle wheel Generator that generates a signal proportional to the wheel speed, from which a def flight speed corresponding Siial is derived; with an electronic liquidity comparison device, which compares both signals and if the difference is one exceeds specified value, a first control signal gives up; with an electronic wheel speed signal differentiating wheel deceleration giver, which emits a second control signal as soon as the wheel deceleration has reached a predetermined level Value exceeds; with a venule device, which receives both control signals and operates in such a way that when a control signal is received the brake pressure is kept constant, the brake pressure when the other control signal is added lowered and at the end of a wheel acceleration signal the brake pressure is released, the hold time after the pressure increase depends on a damping of the wheel deceleration encoder, g e k e η η ζ ei c h η e t d u r c h the combination of features: ₁₀ i ~ ™ rf _pr p of road vehicles with a generator driven by the especially l ° ^^ _neupxad, ! Eder wheel speed proportional signal of em the Ka ^ ^ ^ _{vehicle speed} generated , derived; with an elec- «* Jg £? Velocity comparison device, _i l compares and, if the difference exceeds the value, it _{emits gn} ai; with an e ectromic, wind speed signal differentiating wheel of _{the em} ^ _{control signal} i _ab _ Wheel deceleration a predetermined S ^ with a Venülemrichtung that WeJüber ^^ works that Both Meu ^ _{control signals} i _s the brake pressure con- _1S ^ ⁰ JJg _{50 when} the other control ^s ^ fj joins; _{Brake pressure} lowered and at the end ^ | _a ^d _d ^e _ACC igungs _S ignal _S, the braking pressure free-emej> ™ ^a _{said K} onstanthaltezeit after the gtf * ^ · _{eincr DAEM} pfung of Radverzoge _n ^ _G1 eitschutzeinn _C htungen the "/ _when braking and blocking; 'To prevent _{vehicle degrees.} "It is advantageous to use the measure of the _{slip between wheel uftre} border as a criterion for the _{result of the} control threshold ^^ L ^ arrangements, this slip will compare one of the vehicle speed ₄₅