DE2347878A1 - BRAKE BLOCKING PROTECTION CONTROL SYSTEM FOR VEHICLES, IN PARTICULAR MOTOR VEHICLES - Google Patents

Description

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_χ 1 BERLIN 1 »V. BolivaraHee B \ Tel. 8044205

W / Vh-2982 9/20/73

General Motors Corporation, Detroit, Mich., V.St.A.

Anti-lock control system for vehicles, in particular motor vehicles

The invention relates to a brake lock protective control system for vehicles, especially motor vehicles, "in which a pressure proportional to the speed of the braked wheel is formed, and the brakes to control the wheel- · The slip is alternately ventilated and reapplied in one cycle will.

For the absorption of the braking torque by the Friction between the tire and the road surface gives it a favorable value of the wheel slip. The receptivity for the braking torque decreases when the wheel slip increases.

409819/0668

OWQINAL INSPECTED

In order to achieve effective braking, the braking is carried out in a release cycle that is adapted to the operating conditions and reapplying the brakes made by the one to large deceleration of the braked wheel, which could lead to an increase in wheel slip, is prevented.

In order to obtain the most favorable wheel slip, control systems are known in which the brake pressure is at a substantial Increasing the wheel slip is lowered in order to accelerate the braked wheel to reduce the wheel slip allow during which the brake pressure is kept constant and a certain braking torque until the end of the acceleration of the wheel is exercised, whereupon the brake pressure is increased again to decelerate the wheel again. This cycle is if necessary repeated several times in order to brake under the most favorable possible friction conditions between the tire and the road surface perform.

For example, in such control systems it is known from US Pat. No. 3,441,320 to add a rotating inertial weight use to sense positive and negative wheel accelerations and adjust control valves, which in turn have differential f control the pressures on a brake pressure modulator so that the release, hold and reapplication of the Vehicle braking takes place.

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• In US-PS 3554 612 there is an electronic. Control system used that compares a wheel acceleration signal with a variable reference signal and a brake pressure modulator controls, which lowers the brake pressure, then keeps it constant and then increases it again by one To obtain braking in optimal conditions.

The invention is based on the object of designing an anti-lock control system based on this principle exclusively hydraulic and thus avoiding inertial weights or electronic components, a controller of an automatically shifting gearbox being used as a sensor for the speed and acceleration of the braked wheel.

This object is achieved according to the invention in that a wheel driven at the speed of the braked wheel Regulator the pressure proportional to this speed and a flow rate proportional to the wheel acceleration or the wheel deceleration causes a memory when accelerating the braked wheel via a valve with fluid of the wheel speed proportional pressure is charged and when the braked wheel is decelerated, the liquid via a throttle point with a to a predetermined threshold value of the throttle

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-to provide limited maximum flow rate, and when the braked wheel is decelerated with a value corresponding to a higher flow rate, a pressure difference between the pressure proportional to the speed of the braked wheel and the accumulator pressure actuates a control device which, depending on the size of this pressure difference, actuates the alternating ventilation and reapplication of the brakes in the cycle.

In one embodiment of the invention it is provided that the controller, when the braked wheel accelerates, leashes fluid flow in one direction with one of the ! Acceleration of the braked wheel proportional to the flow rate and when decelerating the braked wheel, a flow of fluid in the opposite direction with one of the decelerations of the braked wheel proportional flow rate

supplies that the valve through which the accumulator is charged is a check valve, and that on the one at the throttle point Occurring pressure difference between the wheel speed proportional pressure and the storage pressure responsive control device is a control valve that controls a brake pressure modulator, and the threshold value of the throttle point is selected so that the maximum flow restriction is that of a maximum permissible deceleration of the braked wheel does not exceed the corresponding value without risk of locking.

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According to a further feature of the invention is

provided that when the wheel accelerates above a specified

benenes Wert devices ä & B disconnect the connection between the control valve and the brake pressure modulator and keep the latter in the current operating state. For this purpose, it is provided according to a further feature of the invention that the separation of the connection between the control valve and the brake pressure modulator and the holding of the latter in the current operating state are carried out by a holding valve, which is triggered by a valve that senses the acceleration of the braked wheel when it is exceeded a specified value of the acceleration is actuated »*

It is further provided that the control valve has surfaces on a valve slide which are opposite to one another are acted upon by the accumulator pressure or the wheel speed proportional pressure, and one of the difference between these Press proportional movement of the valve slide changes the control pressure supplied to the brake pressure modulator.

In another embodiment of the invention it is provided that a brake valve can be actuated alternately in order to transfer pressure fluid from a pump to a brake -one braked wheel to direct and one on the difference between

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the pressure proportional to the wheel speed and the accumulator pressure responsive control valve between the brake valve and the The brake is on and when the pressure difference is activated, the connection between the brake valve and the brake is interrupted j and the latter relieved. In a further development of this tax

j system it is provided that the controller is activated when the braked wheel a fluid flow in one direction with an acceleration of the braked wheel proportional Flow rate and with the deceleration of the braked wheel a flow of liquid in the opposite direction a flow rate proportional to the deceleration of the braked wheel provides that the valve through which the accumulator is charged is a check valve, and that parallel to the Throttle point designed for a maximum flow rate Thermostatic valve is arranged, which opens when the temperature of the liquid is below a predetermined value. Finally, in such a control system for a motor vehicle with a SaS Ρφηρβ as the pressure fluid source and with a self-shifting change-speed gearbox that produces a pressure when the idle speed and the forward drive are switched on supplies, whereby the controller synchronizes with the wheels about the change

transmission is driven and the brake valve can be operated arbitrarily and the pressure of the pump to apply the brakes

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modulated, it is provided that a cycle valve is provided, which the memory via the valve controlling its charging for a predetermined time after switching to idle or a forward gear, the reverse drive is switched off

indicating pressure, and then the memory and the i

j valve controlling its charging to the valve proportional to the wheel speed Pressure is connected.

In both embodiments according to the invention can use the anti-lock control system within the housing of the automatically shifting gearbox.

Exemplary embodiments of the invention are shown in the drawings. Show in the drawings

Fig. 1 is a schematic representation of a preferred embodiment of a brake lock control system for a motor vehicle according to the invention,
Fig. 2 is a diagram in which the braking and the

Tire torque is shown over wheel slip,

Fig. 3 is a graph in which the speed and the brake pressure are plotted against time,

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Fig. 4 is a graph in which the wheel acceleration or delay plotted against time, is

Fig. 5 is a schematic representation of a modified one Embodiment of an anti-lock control system according to the invention.

According to Fig. 1, the rear wheels 10 and 12 are one

■ motor vehicle in the usual way with the output shaft of a "

■ automatically shifting change gear 14 connected. The self ^ b actively shifting change gear 14 contains a regulator, which is driven nron of the output shaft in a line 16 pressure fluid with a pressure proportional to the mean speed of the rear riders. For this purpose he is called Two-stage regulator designed with an almost linear dependency between the .wheel speed and the regulator pressure.

The pressure provided by the regulator in line 16 will in future be referred to as Pg. The automatically shifting change gear 14 also contains a pump that is connected to the input shaft of the gearbox is connected, and in a line 18 a pressure P} delivers.

The brake system contains the usual wheel brakes 20 and 22 on the rear wheels 10 and 12, as well as on the ones not illustrated front wheels of the vehicle. A common main

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brake cylinder 24 with brake booster is via a line 26, a brake pressure modulator 28 and a line 30 with the wheel brakes 20 and 22 connected for the rear wheels. Another line 32 connects the master cylinder 24 to the front wheel brakes.

The brake lock protection control system according to FIG. 1 contains a memory 80, the fluid with that of the wheel speed proportional pressure stores, a throttle valve. 128, flows off via the liquid stored in the memory when the braked wheel decelerates, with a maximum The flow rate that corresponds to a maximum wheel deceleration without the risk of locking, the anti-lock control system also contains a control valve 100, the valve slide is linear to the difference between the speed-dependent Pressure and the accumulator pressure moves and thus the control pressure to the brake pressure modulator 28, to a holding valve 194, which the Separates brake pressure modulator 28 from control valve 100 in order to maintain the prevailing status in the brake cycle, and to an acceleration valve 160 which closes the holding valve 194 while the wheel is accelerating and opens while the wheel is decelerating.

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I ■ ■ -ίο -. ,

"I.

i j

Brake pressure modulator 28 ι

The brake pressure modulator 28 contains a valve chamber 38 in a housing 36, to which the line 26 is connected is, and an outlet chamber 40 to which the line 30 is connected is. A valve member 42 is located in the valve chamber 38 j

and by the force of a spring 44 closes the outlet chamber j

40 from. In the housing 36 is sealed displaceably provided a <bar 46, which forms a movable "wall of the outlet chamber! 40th A collar 48 on the rod 46 abuts against a cup 50, which is provided with a flange on which a spring 56 presses so that the cup and the rod 46 are pressed into the left end position shown in Fig. 1, in this the valve chamber 38 is connected to the outlet chamber 40, so that there is a free connection between the master cylinder 24 and the wheel brakes 20 and 22 The spring 56 is selected to be so strong that it prevents movement of the rod 46 by the braking pressure acting on it in the outlet chamber 40. The collar 48 on the rod 46 also rests against a bushing 54 which is connected to a cup 58 The cup 58 supports a diaphragm 60 which delimits a chamber 62. "In the chamber 62, a brake modulator control pressure Pc acts on the diaphragm 60, which via the sleeve 54 ^. the rod 46 in the left end position according to Fig. 1 regardless of the force of the spring

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56 presses. An annular piston lies against the flange of the cup 50 66, which delimits a chamber 68 in the housing 36. The chamber

j 68 is connected to the pump of the gearbox via line 18. Due to the pump pressure, one is countered to the right

j the force of the spring 56 directed force exerted so that

the rod 46 moves in response to changes in the brake modulator control pressure Pc in the chamber 62. The brake modulator control pressure falls Pc in the chamber 62, the rod 46 is opened by the combined action of a spring acting on the cup 58 ! 72 and the brake pressure in the outlet chamber 40 is moved to the right, so that the spring 44, the valve member 42 for interruption ι

the connection between the master cylinder 24 and the Hin- j terradbremsen 20 and 22 switches. Another decrease in the Brake modulator control pressure Pc causes the rod 46 to move further to the right and thus a reduction in the brake pressure in the outlet chamber 40 and * qer line 30 to the Reduce brake pressure on the rear brakes 20 and 22. A subsequent increase in the brake modulator device pressure Pc moves the rod 46 to the left to increase the pressure in the outlet chamber 40 and further to lift the valve member 42, in order to restore the free connection between the brake master cylinder 24 and the rear wheel brakes 20 and 22. It is

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This creates a conventional brake pressure modulator that can override the driver's influence on the brake pedal, the brake pressure at the wheel brakes being a function of the chamber 62 is supplied to the brake modulator control pressure.

Memory 80 and throttle point 128

The memory 80 has a housing 82 with a bore 84. In the housing 82, a membrane 86 is fixed with its edge, so that it forms a storage chamber 88 in the housing. The middle part of the membrane 86 is through a Piston 90 supported, which is loaded to the right in Fig. 1 by a spring 92 of a predetermined spring rate. The from The pressure Pg, which is dependent on the wheel speed, is transferred to the chamber 88 via line 16, the acceleration valve to be described below 16O, a line 96 and a check valve 98 supplied. The speed-dependent pressure Pg moves the diaphragm 86 of the memory 80 to the left in order to store a volume of liquid with the speed-dependent pressure. There is one almost linear displacement of the diaphragm 86 proportional to the wheel speed, since the speed-dependent pressure Pg itself almost a is a linear function of wheel speed. The speed of the membrane 86 and the flow rate in the reservoir is therefore proportional to the wheel acceleration. In the same way, the speed of the membrane 86 and the flow rate at

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Emptying the memory of the wheel deceleration proportionally. ; The throttle point 128 represents a Umfeeh ^ ung the return j impact valve 98 and allows the outflow of the liquid {from the memory 80 during the deceleration of the braked wheel " The outflow of the liquid from the storage chamber 88 takes place

via the throttle point 128 to the line 96 and via a back!

check valve 130 to line 16, which leads to the controller. The j

The size of the throttle point 128 is selected so that the maximum flow rate corresponds to a wheel deceleration of 1.5 g. This j delay is somewhat greater than that, based on experience, with
The greatest possible braking of a vehicle that occurs with the highest coefficient of friction between the tires and the roadway without excessive wheel slip, i.e. under operating conditions,

where the best possible absorption of the braking torque is given j

ι is. If the rear wheels are delayed to such an extent that

the liquid flowing off from the reservoir 80 is less than
the maximum flow rate of the throttle point is 128, so
the accumulator pressure Pu falls synchronously with the speed-dependent one
Pressure Pg.If the rear wheels are decelerated so much,
that a quantity of liquid would have to flow out of the storage tank,
which is greater than the maximum flow rate of the throttle point 128, then the throttling which then occurs causes a
slower decrease of the accumulator pressure Pu compared to the speed4

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dependent pressure Pg. In the case of excessive braking torque, the accumulator pressure Pu therefore becomes a gradually decreasing reference pressure for initiating an optimal braking process. the Pressure difference between the storage pressure Pu and the pressure in the line 96, which is referred to below as Pk, corresponds the speed difference between the optimal wheel speed and the actual wheel speed. This pressure difference actuates the control valve 100.

Control valve 100

The control valve 100 contains a valve slide 102 in a bore 104 of the housing 82. A control collar 106 of the valve slide 102 forms a wall of the storage chamber and is normally against a stop surface 108 of the Housing 82 held by a spring 110. In this position of the valve slide 102 sets a control collar 112 of the valve slide the connection between an inlet port 114 of the control valve 100 and the line 118, which carries the pressure P1, and establishes the connection to a line 120. The den Line 96 carrying pressure Pk is connected via an opening 124 at the right end of the valve slide. The valve slide 102 is therefore normally pressure-balanced, since the pressures Pk and Pu of equal magnitude act on its two ends. However, it is moved to the left end position by the spring 110

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Fig. 1 pressed. If the pressure difference between the If Pu and Pk press the preload j given by the spring 110 of approximately 0.14 kg / cm, the valve slide 102 moves proportional to the pressure difference between the pressures Pg or Pk and Pu to the right. This movement of the valve spool 102 represents the differential of the flow rate from the accumulator when the wheel decelerates. A clockwise movement of the valve slide 102 as a function of a wheel deceleration of a value which is above that corresponding to the threshold value of the throttle point 128 The pressure P1 is shut off by closing the opening 114 by the control collar 116. At the same time, the brake modulator control pressure Pc is released from the chamber 62 of the braking time modulator 28 through the holding valve 194, the line 120 and the control valve 100 are directed to an outlet opening 131, which via a further to be described Memory 140 relieved at a relief opening 132. The outflow of pressure fluid from the chamber 62 is in the Brake cycle the phase of brake release initiated.

The throttle point 128 works with a flow rate corresponding to the Aaslagewert of 1.5g, since the clockwise movement of the valve slide 102 against the force of the spring 110 limits the accumulator pressure Pu, whereby a control of the outflow is limited to the specified flow rate by the throttle point.

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Memory 140

The memory 140 has a housing 1 $ 2 with a bore 144, in which sealed a. Piston 146 slashed ^ i is. Of the Piston is pressed into the right position shown in FIG. 1 by a spring 148 and is moved to the left when oil Via the outlet opening 131 of the control valve 100, it enters the chamber 150, as mentioned, from the chamber 62 of the brake pressure modulator 28 flows off at the beginning of the brake release. The liquid exits the chamber 150 via a throttle point via the relief opening 132 ″, so daxs a controlled Lowering of the brake modulator control pressure Pc in the chamber 62 of the brake pressure modulator 28 occurs. Lowering the pressure Pc in chamber 62 allows valve member 42 to disconnect between rear brakes 20 and 22 and the master brake cylinder 24 and the subsequent lowering of the pressure at these brakes when the rod 46 is in the Outlet chamber 40 acting brake pressure is moved further to the right. Is the brake pressure lowered enough to reduce the braking torque lower that it is caused by the friction between the tires and the roadway can be recorded, the speed-dependent begins DruckPg to rise ^ whereby the memory 80 is recharged.

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Accelerator valve 160

The accumulator 80 is charged with the pressure Pg | via the acceleration valve 160, which has a housing 162 with | having a bore 164. In the bore 164 is sealed: a valve slide 166, which is pushed into the left end position against a stop 170 by a spring 168 j (Fig. 1). In this position, a control collar 172 blocks the connection between an inlet opening 174 and an outlet opening 176 to the line 96 carrying the pressure Pk, so that the speed-dependent pressure Pg is shut off. A second StHuerbund 180 of the valve slide 166 blocks the connection of the pressure P1 from an inlet opening 182 to an outlet opening 184 and releases the connection of the outlet opening 184 to a relief opening 185. Through the line 96 is the pressure Pk is passed through an inlet opening 188 to the right-hand side of the valve slide 166 in order to increase the force of the spring 168 Against this force, the movement of the valve slide 166 to the right takes place by the one acting on the left side speed-dependent pressure Pg. If the speed-dependent pressure Pg increases during acceleration of the braked wheel, so the pressure Pk and the force of the spring 168 is overcome, so that the valve slide 166 moves to the right. the Inlet opening 174 thereby becomes with outlet opening 176

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connected, so that liquid with the speed-dependent pressure j

i Pg flows through the check valve 98 to the storage chamber 88, that is, the storage device is recharged with speed-dependent pressure Pg. At the same time, the relief opening 185 I is shut off and the inlet pressure leading to the liquid is

Opening 182 connected to the outlet opening 184. The simultaneous Feed of the speed-dependent pressure Pg to the storage chamber 88 via the check valve 98 and to the right-hand side of the valve slide 102 via the opening 124 results in a pressure equalization at the valve slide 102 of the control valve 100, so that

link e

this is moved into the / end position according to FIG. This takes place again the connection between the inlet opening 114 and the outlet opening 118 of the control valve, so that the pressure Pl reaches line 120 again. The spring 110 returns the valve slide 102 to the left end position according to FIG. 1 shortly before the speed-dependent pressure Pg reaches the accumulator pressure Pu used as reference pressure again «

Holding valve

The holding valve 194 has a housing 196 with a bore 198 in which a valve slide 202 is arranged in a sealed, displaceable manner. The V _e ntilschieber 202 1 is in the left end position .gemiss Fig. Biased by a spring 204. In this position, an opening 206 with the control valve 100 is through

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the line 120 is connected and establishes a connection via an opening 208 to a line 210 to chamber 62 of the brake pressure modulator 28. The outlet opening 184 of the acceleration valve 160 is connected to an inlet port 212 on the left side of the valve slide 202 of the holding valve, see above that when the valve slide 166 of the accelerator valve 160 is in its right position during charging of the reservoir 80 liquid with the pressure Pl via di & opening 182 is passed to the left side of the valve slide 202, which is thereby moved to the right and the connection interrupts between the chamber 62 of the brake pressure modulator 28 and the control valve 100. The pressure Pc in chamber 62 of the brake pressure modulator 28 is thereby kept constant at the currently prevailing value, whereby the holding phase the braking cycle is initiated, which lasts until the end of the wheel acceleration.

The holding valve remains in the right position to reduce the pressure Pc in the chamber 62 of the brake pressure modulator amx to keep constant as long as the speed-dependent pressure Pg rises. When the pressure Pg stops rising, the spring 168 moves the valve slide 166 of the accelerator valve to the left, as a result of which the pressure P1 on the left side of the valve slide 202 is relieved via the relief opening 185

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j will. The spring 204 can then the valve slide 202 of the holding

'Move the valve to the left in order to control the fluid with the pressure Pl

; via the control valve 100 and the holding valve 194 for movement ! of the rod 46 to the left, whereby the valve member i 42 is opened and the connection between the main brake cylinder 24 and the rear wheel brakes 20 and 22 is restored

; is provided. This renewed supply of the pressure Pl to the Chamber 62 of the brake pressure modulator increases the brake pressure in a controlled manner by means of one provided in line 18 Throttle point 220.

Way of working

Starting the prime mover

When the drive machine starts up, the input, input shaft of the gearbox 14 to the pump, so that a pressure Pl via the line 18 to the chamber 68 of the brake pressure modulator 28 is directed. The piston 66 of the brake pressure modulator is therefore moved to the right and lifts the cup 50 from the collar 48 of the rod 46. At the same time, the pressure Pl through the control valve 100, the line Ü20 and. through the hold valve passed to the chamber 62 of the brake pressure modulator 28. The pressure Pc in the chamber 62 acts on the diaphragm 60, around the rod to hold in their end position on the left in Fig. 1, in which the valve

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member 42 opens the outlet 40 so that a free encryption _(connection between the master cylinder 24 and the rear wheel brakes 20 and 22 is composed,

Accelerating the vehicle

When the vehicle is driven, the controller delivers a pressure Pg that corresponds to the mean speed of the rear wheels and acts in line 16. For wheel accelerations above 0.5 g, which value is due to the preload by the spring of the accelerator valve 160, the pressure Pg is passed through the accelerator valve 160 to the line 96. The pressure Pk prevailing in this corresponds to the pressure Pg and is via the check valve 98 of the storage chamber of the memory 80 supplied. A volume of liquid that the ι mean wheel speed is proportional, is in the memory 80 ι stored with a pressure Pu which is equal to the pressures Pg and Pk! is. The pressure Pg also acts on the right side at the same time

of the valve slide 102 of the control valve 100 to this valve slide To make pressure balanced, so that the spring 110 the valve slide 102 in the left shown in Fig. 1 End position holds. Is the memory 80 through the accelerator valve 160 is charged, the acceleration valve directs pressure P1 to the holding valve 194, whereby a rightward movement of the

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Valve slide 202 of the holding valve is effected. As a result, the chamber 62 of the brake pressure modulator 28 is controlled by the control valve 100 separated. In this case, a pressure: Pc is maintained in the chamber 62, which corresponds to the pressure Pl, the j rod 46 is held in its normal left-hand configuration, j in which the valve member 42 keeps the outlet chamber 40 open.

Wheel deceleration

When the wheel is decelerated, the wheel speed and thus the pressure Pg decrease. The control system is designed so that the threshold value of the flow rate of the throttle point 128, corresponding to a delay of 1.5g, is slightly above the value for a maximum deceleration, which at the highest coefficient of friction is between Tires and road surface can occur when braking the vehicle. In the case of wheel decelerations of less than 1 _f 5g, the liquid flows out of the reservoir 80 via the throttle point 128, so that the pressure Pu in the reservoir falls synchronously with the pressures Pk and Pg. Dek ¹ pressure Pu from the storage chamber 88 and the pressure Pk act on the valve slide 102 of the control valve 100 in opposite directions and cause a pressure equalization, so that the spring 110 hold the valve slide 102 in its left end position according to FIG. 1, in which pressure Pl of the chamber 62 of the brake pressure modulator 28 is fed.

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Wheel deceleration with more than 1.5g

If too strong a brake pressure is applied to the wheel brakes by the master brake cylinder 24, a braking torque is generated that is not absorbed by the friction between the tires and the road surface can be so that an increased wheel slip occurs. This initiates the brake lock protection.

For an explanation of the brake lock control system, reference is made to the diagrams according to FIGS. 2 to 4. 3-n Fig. 2 shows the braking torque and the frictional torque plotted against the wheel slip. If the driver actuates the master cylinder, the brake pressure causes the braking torque to ^{rise from point a 1 in FIG} , in which the wheel speed and the brake pressure are plotted against time. The speed difference between vehicle and wheel, usually called wheel slip, increases with the braking torque and causes an increase in the friction torque by which the vehicle is decelerated, as illustrated in FIG. 4, in which the wheel acceleration or deceleration is plotted over time. Elevated

the brake pressure (Fig. 3) over the point b «, then begins the Difference between the braking torque and the frictional torque to develop and thus between the wheel speed and the vehicle

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speed. If the braking torque is allowed to be unaffected along the dashed line in Fig. 2, the condition of wheel lock or $ 100 wheel slip becomes Schnell.eriges, in which case the vehicle is decelerated by a "significantly smaller friction torque than in the peak of the frictional torque curve is available. This results in a deteriorated braking of the vehicle.

The outflow of the liquid from the reservoir 80 decreases proportionally with the wheel deceleration, since the wheel speed and thus the speed-dependent pressure Pg decrease. If the wheel deceleration exceeds the threshold value corresponding to l _f 5g, the threshold value of the flow rate of the throttle point 128 is reached. This occurs approximately at point b ¹ in the individual curves. The pressure Pg and thus the pressure Pk decrease faster than the outflow from the accumulator takes place, so that the Pu in the memory cannot follow through the outflow via the throttle point 128. The resulting pressure difference between the pressures Pu and Pk also acts on the valve slide 102 of the control valve 100. If this pressure difference between the pressures Pu and Pk exceeds the preload of the spring 110, the valve slide 102 is moved to the right in order to initiate the release of the brakes in the braking cycle. The outflow of the liquid from the through the throttle point 128

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Memory 80 is with decreasing wheel speed and decreasing Pressure Pg is proportional to the maximum achievable wheel deceleration at the highest coefficient of friction between the tire and the road. The speed, with which the pressures Pg and Pk decrease is proportional to the actual wheel deceleration during braking. The movement of the valve slide 102 of the control valve 100 due to the pressure difference Pu-Pk is the integral of the relative Wheel acceleration flow rate so that the displacement of the valve spool 102 is proportional to the relative wheel speed is. The rightward movement of the valve slide 102 takes place at relative speeds between 3.2 and 6.4 km / h and causes a blocking of the connection of the line 18 carrying the pressure P1 from the holding valve 194 and the chamber 62 of the brake pressure modulator 28, while the pressure Pc is relieved via the accumulator 140. Liquid at pressure Pc from chamber 62 of the brake pressure modulator 28 flows through the holding valve 194 and the control valve 100 to the memory 140 and is stored there and relieved in a controlled manner via the throttle point 152, so that there is a controlled decrease in the pressure Pc in the Chamber 62 of the brake pressure modulator M gives rise to the speed is determined, with which the rod 46 is moved to the right to close the outlet chamber 40, wherein at this movement the pressure to the rear brakes 20 and 22 is lowered. This movement of the valve spool 102 of the control

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valve 100 begins at point c ¹ in the individual curves and after an initial delay, the lowering of the brake pressure is ended at point c ".

Lowering the brake pressure allows the braked wheel to accelerate. This starts at point d! and then with a smaller increase at point e ·, after which the wheel accelerates faster. At point e ″, the increasing pressure Pg reaches the threshold value 0.5g of the acceleration valve 160, so that its valve slide 166 is moved to the right and directs the pressure Pg to the line 96. This begins a reloading of the memory 80. The rightward movement of the valve slide 166 also establishes the connection of the line 18 carrying the pressure P1 with the holding valve 194, as a result of which the valve slide 202 is moved to the right and the connection between the chamber 62 of the brake pressure modulator 28 and the control valve 100 and the one currently prevailing in the chamber 62 is interrupted Since the accumulator 80 is charged with fluid of the speed-dependent pressure Pg, the pressure difference between the pressures Pu: and Pk is reduced, so that the spring 110 moves the valve slide 102 of the control valve 100 into the left position, whereby the connection of the line 18 carrying the pressure P1 is restored with the holding valve 194.

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The hold valve 194 remains closed during wheel speed

Il

continues to catch up. If the wheel acceleration falls below 0.5g at point f ¹ , which indicates that the wheel speed is approaching the vehicle speed, the spring 168 switches the valve slide 166 to the left and the pressure on the left side of the valve slide 202 of the holding valve 194 is via the Relief opening 185 relieved. The spring 204 then moves the valve slide 202 of the holding valve to the left, so that the pressure Pl at the control valve is fed to the chamber 62 of the brake pressure modulator 28 via the controlling throttle point 220, whereby the rod 46 moves to the left an increase in the brake pressure from point f "and that The rear wheel brakes 20 and 22 are reapplied.

The anti-lock control system then repeats

releasing the brakes, holding the brake pressure and applying the brakes again until the vehicle has come to a standstill or excessive braking by the driver ends.

Fig. 5 shows a modified embodiment of a Brake anti-lock control system according to the invention, in which an arbitrarily actuatable brake valve pressure fluid from controls the pump to the wheel brakes. The anti-lock control system works in the rest of the memory of

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Liquid with a speed-dependent pressure and an outflow with an intermediate circuit of a throttle point in the same way ; like the corresponding parts of the system of the first embodiment

j shape.

A vehicle has rear wheels 310 and 312 which are shown in Usually via a drive shaft and a differential gear from the output shaft of an automatically switching Gearbox 314 are driven. The automatically shifting gearbox 314 has a connection to the output shaft. bound controller, which is driven with the middle speed of the rear wheels and one of the middle speed of the Wheels 310 and 312 proportional pressure in a line 316 promotes. The controller is designed as a two-stage controller, see above that it has an essentially linear relationship between the wheel speed and the regulator pressure. This speed-dependent Pressure in line 316 is hereinafter referred to as Pg. The automatically shifting gearbox 314 has Furthermore, a pump driven by the input shaft of the gearbox, which supplies a pressure P1 in a line 318. Furthermore, the automatically shifting change gearbox 314

a hydraulic switching control circuit, one of which is the output

switching the reverse / displaying pressure provides the following is denoted by Pnr, and which corresponds to the pressure Pl

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This pressure is fed to a line 321 when the
Gearbox is switched from reverse drive to idle or forward drive.

The brake system of the vehicle has conventional wheel brakes 320 and 322, which the rear wheels 310 and 312, respectively
are assigned as well as conventional wheel brakes 324 and 326, the
Front wheels 328 and 330 are assigned. The brake pressure
is supplied to the wheel brakes through a brake valve 334, the

in Fig. 5 in the position for released brakes is drawn.j In this position, the line leading the pressure Pl is automatically with a relief line 338 to the sump of the
switching gearbox 314 connected. The brake valve 334 is operated by a conventional brake pedal 340 by
when depressing the valve spool 336 is moved to the left. This throttles the connection between the line and the relief line 338 and opens a connection between the line 318 and a line 342, which transfers the brake pressure Pb directly to the front wheel brakes 324 and 326 and via a logic circuit to be described later to the rear wheel brakes 320 and 322.

In general, the hydraulic logic circuit for the brakes contains a memory 380 which stores a volume of fluid with the speed-dependent pressure Pg, a Throttle 428, through the liquid from the memory to the

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Regulator flows out during the delay, with a maximum

! Flow rate according to the known maximum wheel flow

! j

■ Delay without risk of blocking is set to a control valve! j 400, which is in linear proportion to the difference between

the accumulator pressure and the speed-dependent pressure and here the supply of the brake pressure Pb to the rear wheel brakes 320 and 322 throttles and the brake pressure from the rear wheel brakes 320 and 322 relieved, a hold valve 494 that disconnects the rear wheel brakes from the control valve 400 when the braking cycle is in the braking pressure holding phase, and an accelerator valve 460 that controls the wheel acceleration senses and the hold valve 494 closes when the wheel accelerates and opens when the wheel is accelerating delayed. The logic circuit also includes a thermostatic valve 544 which controls the throttling members 428 at low operating temperatures bypasses, in which the viscosity of the liquid the flow through the throttle point 426 too strong throttles and also a cycle valve 516, which when switching the gearbox from reverse drive to idle or a forward drive acts on the accumulator, the acceleration valve and the holding valve.

-31-

409819/066 8

-31 accumulator 380, control valve 400 and throttle point 428

The memory 380 has a housing 382 with a bore 384. In the housing 382 is a membrane 386 with her The edge is retained and delimits a storage chamber 388. The middle part of the membrane 386 is supported by a piston 390, which is loaded in its right position according to FIG. 5 by a spring 392 of a predetermined spring rate. liquid with speed-dependent pressure Pg, the chamber 388 of the accumulator 380 via the line 316, the still to be described Accelerator valve 460, a line 396 and a check valve 398 are supplied. The speed-dependent pressure Pg moves the membrane 386 of the accumulator 380 to the left and stores a volume of liquid with a speed-dependent pressure Pg. The membrane 386 carries out an approximately linear displacement proportional to the wheel speed, since the speed-dependent movement Pressure Pg itself is almost a linear function of the mean wheel speed. The speed of the membrane 386 and the The flow rate in the memory 380 is therefore proportional to the wheel acceleration. The movement of the diaphragm is the same 386 and the outflowing flow rate of the wheel deceleration proportional.

The restriction 428 bypasses the check valve 398 and allows the fluid to return from the reservoir 380 to the controller during the deceleration of the wheel. The liquid

. -32- 409819/0668

Speed flows out of chamber 388 to line 396 and via a Check valve 430 to the line 316 carrying the pressure Pg and from there back to the regulator. The throttle point 428 is designed so that its flow rate is limited to a value corresponding to a delay of 1.5g. This The value is somewhat greater than that which, according to experience, is at Braking with the greatest coefficient of friction between the tires and the road surface can be achieved without excessive slip. Delay the vehicle wheels in such a way that the amount of liquid flowing off from the reservoir 380 is less than the maximum flow rate the throttle point 428, the accumulator pressure Pu falls synchronously with the speed-dependent pressure Pg. Delay meanwhile, the vehicle wheels are stronger, so that the amount of liquid flowing out of the reservoir is greater than the maximum If the flow rate of the throttle point 428 is, the accumulator pressure Pu 'falls more slowly than the speed-dependent pressure Pg. In the case of excessive braking torque, the accumulator pressure Pu cannot follow the falling pressure Pg and thus becomes a gradual one decreasing reference pressure, which allows optimal control of the braking process. The pressure difference Pk between the storage pressure Pu and the pressure in the line entspticli the speed difference between the optimal Wheel speed and actual wheel speed; and this pressure difference operates the control valve 400.

-33-409819 / 0668

Control valve 40O

The control valve 400 has a valve slide 402, which is sealed and displaceable in a bore 404 of the housing 382 is. A control collar 406 of the valve slide 402 forms a ¥ and the Speioherkammer 388 and is normally against a stop surface 408 of the housing 382 is held in abutment by a spring. In this normal position of the valve slide 402 sets a control collar 412 of the valve slide the connection between the line 342 carrying the brake pressure Pb and an inlet opening 414 of the control valve 400 is free, while a control collar 416 of the valve slide 402 opens an opening 418, so that the brake pressure Pb via a line 420 and hold valve 494, to be described, goes to rear brakes 320 and 322. The pressure Pk in line 396 acts through an opening 424 on the right side of the valve spool 402 on this, so that this is pressure-balanced by the mutually equal pressures Pu and Pk and in the left ^ i End position according to FIG. 5 is held by the spring 410. Ascends the pressure difference between Pu and Pk the preload

the spring 410, which is about 0.14 kg / cm, the valve slide 402 is moved to the right, and accordingly the pressure difference between the pressures Pg or Pk and the reference pressure Pu. This movement of the valve slide 402 stell. · !;

-34-

AO 9 819/0668

'-34- . - _λ

the integral of the relative wheel acceleration flow rate from the memory 380. The movement of the valve slide 402 to the right as a function of the wheel deceleration above the threshold value given by the throttle point 428 causes the brake pressure Pb to be shut off by the control collar 416 between the inlet opening 414 and the opening 418 and opens the connection between the rear wheel brakes 320 and Via the holding valve 494, the line 420 and the control valve 400 to an outlet opening 431, which is in communication with a relief opening 432. The brake pressure on the rear brakes is thus relieved at a predetermined speed via the relief port 432 to in the Bremszyiklus initiate the brake release phase.

The throttle point 428 works with the äuslagegemässen Flow rate, since the valve slide 402 moves so far to the right that a pressure difference between each other opposing pressures Pu and Pk the force of the spring 410 times the face of the valve slide 402 is equal

Accelerator valve 460

ßäs charging of the memory 380 with hydraulic fluid with the pressure Pg takes place through the accelerator valve 460.

-35-

4.0 9819/0668

, The accelerator valve 460 has a housing 462 with a Bore 464 in which a valve slide 466 is arranged in a sealed, displaceable manner. A spring 468 pushes the valve spool 460 in the left end position according to FIG. 5 against a stop 470. In this position, a control collar 472 feeds a connection between an inlet port 474 and an outlet port 476 for the speed-dependent pressure Pg. the Outlet port 476 is connected to line 396. A second control collar 480 of the valve slide 466 blocks the connection from an inlet port 482 to which the line with Pnr pressure is connected to an outlet port 484, which in turn has a connection with a relief opening 485. Through the line 396, the pressure Pk is passed to the right side of the valve slide 466 via an opening 488 and below supports the spring 468, the movement of the valve slide 466 to the right by the on the left side of the valve slide acting speed-dependent pressure J? g opposes. If the speed-dependent pressure Pg increases during the acceleration of the braked wheel, the pressure Pk and the Overcome spring 468, so that the valve slide 466 is moved to the right. As a result, the inlet opening 474 'becomes with it the outlet port 476 is connected to the line 396, which -over the Check valve 398 is connected to the storage chamber 388

-36-

409819/0668

The memory 380 is consequently with the hydraulic fluid of the speed-dependent pressure Pg charged again. At the same time, the relief opening 485 is blocked by the control collar 466 and the inlet port 482 with the outlet port connected so that the pressure Pl is forwarded. The simultaneous Feeding of the pressure »Pg to the storage chamber 388 and of the pressure El on the right side of the valve slide 402 Via the opening 424 there is a pressure equalization on the valve slide 402, so that the latter is in its left position according to FIG 5 is moved by the spring 410. This creates the inlet opening 414 reconnected to the outlet port 418. The bias of the spring 410 sets the valve slide 402 back to the left end position according to FIG. 5 shortly before the speed-dependent pressure Pg reaches the reference pressure Pu again ^

Hold valve 494

The holding valve 494 has a housing 496 with a bore 498 in which a valve slide 502 is arranged in a sealed manner. The valve slide 502 is pressed into the left position according to FIG. 5 by a spring 504. In its left position, an opening 506, which is connected to the control valve 400 via the line 420, is connected to an opening 508, which leads with a line 510 to the rear wheel brakes 420 ^: and 422. The outlet port 484 of the accelerator

-37-

409819/0668

valve 460 is connected to an inlet port 512 on the left side of the "valve slide 502, so that when in the right end position located valve slide 466 of the acceleration valve 460 while the accumulator 380 is being charged, the pressure Pnr is passed on to the inlet opening 482 acts on the left side of the valve slide 502 of the holding valve and moves the valve slide 502 to the right. Through this becomes the connection between the rear brakes 320 and 322 and the control valve 400 interrupted. The brake pressure Pb at the rear wheel brakes 320 and 322 is thereby increased to currently prevailing value kept constant, whereby the holding phase of the braking cycle during the acceleration of the braked wheel is given.

The holding valve remains in its right position as long as the wheel speed and thus the speed-dependent one Increase pressure Pg. When the increase in the speed-dependent pressure Pg ends, the spring 468 of the acceleration valve sets 460 whose valve slide 466 to the left, so that the pressure Pl on the left side of the holding valve 502 via the Relief opening 485 is relieved. The spring 504 can then move the valve spool 502 of the hold valve to the left, releasing the brake pressure Pb through the control valve 400 and hold valve 494 back to rear brakes 320

-39-

409819/0668

and 322, which are thus connected to the brake valve 334. Thereby the brake pressure is applied to the Rear brakes increased and caused the brake reapplication phase of the braking cycle.

Cycle valve 516

The cycle valve 516 includes a housing 518 with a bore 520 in which a sealed slidable Valve slide 522 is arranged. The valve slide 522 is in its right position according to FIG. 5 by a spring 524 burdened. If the valve slide 522 is in the right position, a control collar 526 allows the connection of the

at
Inlet port 528, / dTe is connected to the Pnr pressure line 321, to an outlet port 530, which is connected to the inlet port 474 of the accelerator valve 460 and the check valve 430. A second control collar 532 blocks the connection for the speed-dependent pressure Pg between an opening 534 and an outlet opening 530 .. The pressure Pnr in the line 321 is connected via a throttle 538 to an inlet opening 536 on the right side of the valve slide 522 and loads the Valve slide to the left. In the left position of the valve slide 522, its control collar 526 blocks the connection of the Pnr-

409819/0668

Pressure between the inlet port 528 and the outlet port 530, while the speed-dependent pressure Pg a connection takes place between the inlet port 534 and the outlet port 530.

Thermostatic valve 544

The thermostatic valve 544 is responsive to the temperature of the fluid in the antiskid control system and lies parallel to the throttle point 428. Under normal temperature conditions, the thermostatic valve 544 is closed, so that the outflow from the reservoir is controlled by the throttle point 428. When operating in cold weather, the Viscosity of the fluid of the anti-lock control system can be influenced so that the throttle point 428 the braking cycle already initiated when there is no risk of the wheels locking. Under these conditions the thermostatic valve opens 544 to bypass the throttle 428 so that the anti-lock control system is rendered ineffective and the connection between the brake valve and the rear brakes is guaranteed.

-40-

409819/0668

Way of working
Start the engine and apply the brakes

When the engine is started, the input shaft drives of the gearbox 314 the pump, so that in. der, line 318 a pressure Pl arises. Will the brake valve operated by the brake pedal 340, a brake pressure Pb is applied via the line in accordance with the depression of the brake pedal 342 directly to the front wheel brakes 324 and 326 and the rear wheel brakes 320 and 322 through the control valve 400 and the holding valve 494, which are in their normal positions according to FIG. 5.

Switching the gearbox to idling or forward drive ^)

If the gearbox 314 is switched to neutral or forward drive _{by the driver, the pressure Pnr t} prevails in the line 321 and is fed to the acceleration valve 460 via the cycle valve 516, which is in the right position according to FIG. The Pnr pressure acting on the left side of the valve slide 466 dfee acceleration valve 460 shifts the valve slide 466 to the right, whereby the connection with the line 396 is established and the Pnr pressure reaches the storage chamber via the check valve 398 and the

-41- 409819/0668

Membrane 386 moved to the left ". When the valve moved to the right Valve 466 also opens a connection between the inlet port 482 and the outlet port 484 for the Pnr pressure, which is passed to the inlet port 512 of the holding valve 494. This becomes the valve slide 502 of the holding valve moved to the right against the force of spring 504. The Pnr pressure also acts on the right side of the valve slide 522 of the cycle valve via the throttle 538. After a short time, which is determined by the throttle 538, throw the Pnr pressure acting on the right side of the valve slide 522 counteracts a leftward movement of the valve slide 522 the force of the spring 524, whereby the connection to the outlet port 530 for the Pnr pressure is shut off and the outlet port 530 is connected to the inlet opening 534 in order to supply speed-dependent pressure Pg. Assuming that the vehicle has not yet moved, the memory $ 80 is set via the throttle point 428 or, in cold weather, via the thermostat, valve 544 as well as the check valve 430 and the cycle valve 516 to the regulator and to the sump of the gearbox. The spring 468 switches the valve spool 466 of the delay valve 460, whereby the spring 504 the valve spool 502 of the holding valve 494 can switch. The cycle valve 516

-42-

409819/0669

So operates the memory 380, the check valve 398, the check valve 430, the acceleration valve 460 and that Hold valve 494 every ^ time the gearbox is on idle or forward drive is switched.

Vehicle acceleration

If the vehicle is being driven, the regulator of the change gearbox supplies pressure fluid with speed-dependent pressure Pg through line 316 to cycle valve 516 delivered. At wheel accelerations above a threshold value of about 0.5g, which is caused by the preload of the spring 468 of the Acceleration valve 460 is given, the speed-dependent pressure Pg via the acceleration valve 460 of the line 396 forwarded. The pressure Pk is therefore equal to the speed-dependent pressure Pg and passes through the check valve 398 into the chamber 388 of the accumulator 380. An amount of liquid proportional to the mean wheel speed is fed into the accumulator 380 is stored with a pressure Pu which is equal to the pressures Pg and Pk, respectively. At the same time, the speed-dependent pressure Pgauch is applied on the right side of the valve slide 402 of the control valve, so that this is pressure balanced and through the Spring 410 is held in its left position according to FIG.

-43-

4 * 098 19/066

Wheel deceleration

When the wheel decelerates, the wheel speed and thus the speed-dependent pressure Pg decrease. The restriction 428 is designed for a maximum flow rate that corresponds to a threshold value of about 1.5g, and is slightly above the maximum deceleration at the highest coefficient of friction between tires and the roadway can be reached without excessive wheel slip. If the wheel decelerates less than 1.5g, the throttle point controls 428 the outflow of the liquid from the reservoir 380 so that the storage pressure Pu falls synchronously with the pressures Pk and Pg. The pressure Pu acting in the storage chamber 388 and the pressure on The pressure Pk acting on the right side of the valve slide 402 results in compensating forces on the valve slide 402, see above that the spring 410 holds the valve slide 402 in the left position according to FIG. 5, in which the brake pressure Pb to the rear wheel brakes 320 and 322 is directed.

Wheel deceleration with more than 1.5g

If excessive brake pressure from brake valve 354 the rear brakes 320 and 322 is supplied, results. a braking torque that comes from the friction between the tire and the road surface cannot be absorbed, so that excessive wheel slip occurs. In this case a braking cycle is initiated. To explain the anti-lock control system

-44-

reference is made again to FIGS. 2 to 4. If the driver actuates the brake valve 334, the brake pressure causes the braking torque to rise from point a ¹ in FIG. 2. The resulting braking torque causes a decrease in the wheel speed and thus a decrease in the speed-dependent pressure Pg, as shown in FIG. 3. The speed difference between the vehicle and the wheel, usually called wheel slip, increases with the braking torque and causes an increasing tire torque, by means of which the vehicle is decelerated, as shown in FIG. 4. If the brake pressure (FIG. 3) increases above point b ¹ , the development of a substantial difference between the braking torque and the tire torque and thus between the wheel speed and the vehicle speed begins. If an increase in the braking torque is allowed unaffected according to the dashed line in FIG. 2, the wheel quickly approaches the locked state, i.e. 100 # wheel slip, in which the vehicle is decelerated by a tire torque that is significantly less than the maximum possible tire torque. The outflow quantity from the memory 380 with decreasing wheel speed and thus decreasing speed-dependent pressure Pg decreases proportionally to the wheel deceleration. If the wheel deceleration exceeds a value of 1.5 g, which corresponds to the maximum flow rate of the throttle point 428, then the pressures Pg and Pk decrease faster than the pressure Pu

-45-409819 / 0668

in memory (point b ¹ ). The resulting pressure difference between the pressures Pu and Pk acts on the valve slide 402 of the control valve 400. If this pressure difference Pu minus Pk exceeds the preload of the spring 410, the valve slide 402 of the control valve is moved to the right, which in the braking cycle the phase of releasing the Braking is initiated. The amount of liquid flowing out of the reservoir via the throttle point 428 is proportional to the maximum flow rate of the throttle body 428. The rate at which pressures Pg and Pk decrease is proportional to the actual wheel deceleration during braking. The movement of the valve slide 402 of the control valve due to the pressure difference Pu minus Pk is the integral of the relative wheel acceleration flow rate. The displacement of the valve slide 402 is therefore proportional to the relative wheel speed. The right-hand movement of the valve slide 402 of the control valve takes place at a relative speed between 3.2 - 6.4 km / h and causes the brake pressure Pb to be shut off from the rear wheel brakes 320 and 322 and the brake pressure Pb to be relieved to the relief opening 432, thereby venting the rear brakes 320 and 322 is effected. This movement of the valve spool 402 begins at point c ^f in the individual curves and, after an initial delay, the lowering of d «s Br« «pressure» i «point c» is effected.

-46- _ 409 819/0668

Lowering the brake pressure allows the wheel to accelerate (point d ^r ) and then at a lower speed to point e ¹ , at which the wheel begins to accelerate more rapidly. At point e ″, the speed-dependent pressure Pg, which increases during wheel acceleration, reaches the 0.5 g threshold of the acceleration valve 460, the valve slide 466 of which is switched to the right in order to establish the connection to the line 396, so that the reloading of the memory 380 begins of the valve slide 466 of the accelerator valve 460 opens the connection of the Pnr pressure to the holding valve 494, so that the valve slide 502 of the holding valve 494 is moved to the right and the connection between the rear wheel brushes 320 and 322 and the control valve 400 is interrupted, so that the one on the rear wheel brakes By charging the accumulator 380 with speed-dependent pressure Pg, the pressure difference Pu minus Pk is reduced, so that the spring 410 can move the valve slide 402 of the control valve 400 back into the right position according to FIG. 5 and thus the brake pressure Pb is fed to the holding valve 494. The Hold valve 494 remains closed while wheel speed catches up. If the wheel acceleration falls below 0.5 g at point f ″, which indicates that the wheel speed is approaching the vehicle speed *, then the spring 468 of the acceleration valve 460 switches

• -47-409819 / 0668

its valve slide 466 to the left and the pressure acting on the left side of the valve slide 502 of the holding valve is relieved via the relief opening 485. The spring 504 then pushes the valve slide 502 of the holding valve left, so that the brake pressure Pb from the control valve 400 to the rear wheel brakes and from point f ″ increases Re-application of the rear brakes 320 and 322 causes.

The anti-lock control system repeats the Brake cycle in the same way until the vehicle comes to a standstill or excessive depression of the brake pedal ends by the driver.

409819/0668

Claims (8)

-48 Patent Proverbs: 1. Arm blocker protection control system for vehicles, especially motor vehicles, in which one of the speed of the braked Wheel proportional pressure is formed, and the brakes to control the wheel slip in a cycle alternately ventilated and put on again, thereby It is shown that a controller driven with the speed of the braked wheel (10, 12) controls this speed proportional pressure (Pg in line 16) and a flow rate proportional to the wheel acceleration or the wheel deceleration causes a memory (80) when accelerating the braked wheel via a valve (98) with liquid of the Wheel speed proportional pressure is charged and when decelerating the braked wheel the liquid over a Throttle point (128) with a maximum flow rate limited to a predetermined threshold value of the throttle point flows off, and when the braked wheel is decelerating with a value corresponding to a higher flow rate, a Pressure difference between the speed of the braked wheel proportional pressure (Bg or Pk) and the accumulator pressure (Pu) actuates a control device (100) which depends on the The size of this pressure difference is the alternating ventilation and again applying the brakes in the cycle. -49- 409819/066 8 __ _ _; _ 2. Brake anti-lock control system according to claim 1, characterized in that the controller upon acceleration of the braked wheel a fluid flow in one direction with one of the acceleration of the braked wheel proportional flow rate and with the deceleration of the braked wheel a liquid flow in the opposite Direction with a flow rate proportional to the deceleration of the braked wheel that the valve delivers over that the memory (80) is charged, a check valve (98), and the one at the throttle point (128) Pressure difference between the wheel speed proportional pressure (Pk) and the accumulator pressure (Pu) responsive control device is a control valve (100) that controls a brake pressure modulator (28), and the threshold value of the throttle point (128) is selected so that the maximum flow rate corresponds to the maximum permissible deceleration of the braked wheel without the risk of locking does not exceed the corresponding value. 3. Brake anti-lock control system according to claim 2, characterized in that, when the wheel accelerates above a predetermined value, devices (160, 194) establish the connection separate between the control valve (100) and the brake pressure modulator (28) and the latter in the current operating state keep. -50- 4 0 9 81 970 6 6 8 234787g 4. Brake anti-lock control system according to claim 3, characterized in that the separation of the connection between the control valve (100) and the brake pressure modulator (28) as well as keeping the latter in the current operating state by a holding valve (194) carried out by a. the acceleration of the braked wheel sensing valve (160) when a specified value of the acceleration is exceeded is operated. 5. Anti-lock control system after a of claims 2 to'4, characterized »that the control valve (100) on a valve slide (102) has surfaces which are opposite to one another from the accumulator pressure (Bu) or to which the wheel speed proportional pressure (Pk) are applied, and a movement of the corresponding to the difference between these pressures Valve slide changes the control pressure fed to the brake pressure modulator (28). 6. Brake anti-lock control system according to claim 1, characterized in that a brake valve (334) is optional can be actuated to conduct pressure fluid (Pl) from a pump to a brake of a braked wheel and to the Difference between the wheel speed proportional pressure (Pk) and the accumulator pressure (Pu) responding control valve (400) between the brake valve and the brake and when actuated -51- CO 9819/0668! the pressure difference creates the connection between the brake valve and the brake interrupts and relieves the latter. 7. Brake lock protection control system according to claim 6, characterized in that the controller during acceleration of the braked wheel a flow of liquid in one direction with an amount of cash flow proportional to the acceleration of the braked wheel and with the deceleration of the braked one Wheel a flow of liquid in the opposite direction with a deceleration of the ^ .brremsten wheel proportional The flow rate provides that the valve via which the accumulator (380) is charged is a check valve (398), and that a thermostatic valve (544) is arranged parallel to the throttle point designed for a maximum flow rate, which opens when the temperature of the liquid is below a predetermined value. 8. Brake anti-lock control system according to claim or 7 for a motor vehicle with a pump as the pressure fluid source and with a self-shifting gearbox, which is activated when idling and forward drive supplies a pressure, the controller being driven synchronously with the wheels via the gearbox and the brake valve can be operated arbitrarily and modulates the pressure of the pump for applying the brakes, characterized in that a cycle -52- 40 9 8 1S / 06 6 8_ valve (5l6) is provided, which the memory (380) via the valve (398) controlling its charging for a predetermined Time after switching to idle or a forward gear, a pressure indicating that the reverse drive is switched off and then the accumulator and the valve controlling its charging to the pressure proportional to the wheel speed (Pg) to be connected 9819M6-6S