CA1248161A - Method and device for controlling the distribution of brake force - Google Patents
Method and device for controlling the distribution of brake forceInfo
- Publication number
- CA1248161A CA1248161A CA000448208A CA448208A CA1248161A CA 1248161 A CA1248161 A CA 1248161A CA 000448208 A CA000448208 A CA 000448208A CA 448208 A CA448208 A CA 448208A CA 1248161 A CA1248161 A CA 1248161A
- Authority
- CA
- Canada
- Prior art keywords
- brake
- pressure
- axle
- rear axle
- control
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 238000000034 method Methods 0.000 title abstract description 3
- 238000000429 assembly Methods 0.000 claims description 10
- 230000000712 assembly Effects 0.000 claims description 10
- 239000012530 fluid Substances 0.000 claims description 2
- 230000003068 static effect Effects 0.000 abstract description 5
- 230000003247 decreasing effect Effects 0.000 abstract description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- 230000004913 activation Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 230000006978 adaptation Effects 0.000 description 1
- 230000032683 aging Effects 0.000 description 1
- 230000000903 blocking effect Effects 0.000 description 1
- 238000011109 contamination Methods 0.000 description 1
- 230000002950 deficient Effects 0.000 description 1
- 230000003111 delayed effect Effects 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 230000018109 developmental process Effects 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
- B60T8/00—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force
- B60T8/26—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force characterised by producing differential braking between front and rear wheels
- B60T8/266—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force characterised by producing differential braking between front and rear wheels using valves or actuators with external control means
- B60T8/268—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force characterised by producing differential braking between front and rear wheels using valves or actuators with external control means using the valves of an ABS, ASR or ESP system
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
- B60T8/00—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force
- B60T8/17—Using electrical or electronic regulation means to control braking
- B60T8/176—Brake regulation specially adapted to prevent excessive wheel slip during vehicle deceleration, e.g. ABS
- B60T8/1766—Proportioning of brake forces according to vehicle axle loads, e.g. front to rear of vehicle
Landscapes
- Engineering & Computer Science (AREA)
- Transportation (AREA)
- Mechanical Engineering (AREA)
- Regulating Braking Force (AREA)
- Hydraulic Control Valves For Brake Systems (AREA)
Abstract
Abstract SUMMARY
A Method and a Device for Controlling the Distribution of Brake Force according to DBP... (Patent Application P 33 01 948.7) With a view to controlling the distribution of brake force onto the front and rear axles of an automotive vehicle in response to the momentarily prevailing static and dynamic axle load distribution, the wheel rotational behaviour (? ) on the front axle (VA) and on the rear axle (HA) and the translational deceleration (-b) of the vehicle or variables proportional to said measured values are determined by way of sensors. After the said signals having been electronically processed and combined, the share of the brake pressure (PHA) fed to the rear axle in response to the front wheel brake pressure (PVA) is so controlled that the brake slip at the rear axle (HA) corresponds to the brake slip at the front axle (VA) or is slightly less than the front wheel brake pressure. In the event that nontheless a locking tendency of the rear wheels occurs, e.g. as a result of rapidly changing road conditions, the brake pressure at the rear axis is reduced with the aid of another quick-acting electromagnetically operated valve (6,16) and is maintained constant at the low value until the front wheel pressure has decreased.
Fig. 1.
A Method and a Device for Controlling the Distribution of Brake Force according to DBP... (Patent Application P 33 01 948.7) With a view to controlling the distribution of brake force onto the front and rear axles of an automotive vehicle in response to the momentarily prevailing static and dynamic axle load distribution, the wheel rotational behaviour (? ) on the front axle (VA) and on the rear axle (HA) and the translational deceleration (-b) of the vehicle or variables proportional to said measured values are determined by way of sensors. After the said signals having been electronically processed and combined, the share of the brake pressure (PHA) fed to the rear axle in response to the front wheel brake pressure (PVA) is so controlled that the brake slip at the rear axle (HA) corresponds to the brake slip at the front axle (VA) or is slightly less than the front wheel brake pressure. In the event that nontheless a locking tendency of the rear wheels occurs, e.g. as a result of rapidly changing road conditions, the brake pressure at the rear axis is reduced with the aid of another quick-acting electromagnetically operated valve (6,16) and is maintained constant at the low value until the front wheel pressure has decreased.
Fig. 1.
Description
~8~
The present inven-tion is concerned with a method and a device for controlling the braXe force distribution to the front axle and to the rear axle of an automotive vehicle in response to the static and dynamic axle load distribution and/or other measured variables derived from the braking behaviour, wherein electric signals corresponding to the wheel behaviour at the front axle and at the rear axle and to the translational deceleration of the vehicle are generated, electronically combined and processed.
The brake slip on the front and rear wheels and the measured values proportional to the brake slip, respectively, are deter-mined from the signals generated therefrom, and the brake slip of the rear wheels is limited with the aid of a control to the value of the brake slip on the front wheels or to a va~ue slightly therebelow. This invention is a development of that disclosed in our copending Canadian Application 445,780.
Sensors are provided for measuring the rotational behavlour of the wheels and the translational deceleration/ the output signals of which sensors are combined with Eirmly wired or pro-gramme-controllecl electronic circuits, e.g. a microprocessor, and processed. The brake pressure is controlled with the aid of modulators, e.g. electromagnetically operated control valves.
~' *
1~4~
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The present inven-tion is concerned with a method and a device for controlling the braXe force distribution to the front axle and to the rear axle of an automotive vehicle in response to the static and dynamic axle load distribution and/or other measured variables derived from the braking behaviour, wherein electric signals corresponding to the wheel behaviour at the front axle and at the rear axle and to the translational deceleration of the vehicle are generated, electronically combined and processed.
The brake slip on the front and rear wheels and the measured values proportional to the brake slip, respectively, are deter-mined from the signals generated therefrom, and the brake slip of the rear wheels is limited with the aid of a control to the value of the brake slip on the front wheels or to a va~ue slightly therebelow. This invention is a development of that disclosed in our copending Canadian Application 445,780.
Sensors are provided for measuring the rotational behavlour of the wheels and the translational deceleration/ the output signals of which sensors are combined with Eirmly wired or pro-gramme-controllecl electronic circuits, e.g. a microprocessor, and processed. The brake pressure is controlled with the aid of modulators, e.g. electromagnetically operated control valves.
~' *
1~4~
.
2 - --A brake force distributor is already known in the art in ~hich the static axle load distribution with the vehicle at standstill i5 measured by sensors and the measured data fed into a micro-computer which under consideration of the said measured values and of the measured pressure controls the brake force distrlbution pursuant to a memorlzed mathematical expression in the front and rear axle circuit (European patent application EP~Al 062Z46).
It iB a oisadvantage of such a brake force distributor that the value of adherence between road and wheel at the rear and front axles actually prevailing at the time of the braking operation and depending on numerous parametPrs, cannot exert an influence on the brake force distribution. For this reason, it i5 imperative for the brake, in order to safely avoid the dangerous overbraklng of the rear axle, to oe so designed that in the ma~ority of cases, the rear axle wlll cuntribute little to the braking operation.
Moreover, lt has proved to bP disadvantageous that the actual values in practice considerably differ from the numerically calculated should-be values. The brake characteristics assumed to be constant in the layout of ~he braking force distribution and the memorized mathematical expressian, in practice, are subject to substantial changes, e.g. as a result of manufacturing tolerances in the coefficient of friction, aging, contamination, changes in the spring constant in operation, defective adjustment, heavy temperature changes etc~ ~11 this might result in that the actual characteristic of the brake force distribution considerably differes from the precalculated values.
ThP brake force distributors commonly used nowadays are limited to an invariaoly adjusted pressure-responsive contrnl. Load-responsive or decelearation~responsive brake force regulators are likewise known in a great number of variants. For the afore-going reasons, even when maklng great assembly and adjustment ~z~
~ - 3 -efforts, a satisfactory adaptation can be attained with these prior art devices, at best, in one of the two extreme "unloaded/
loaded" conditions so that, in a multiplicity of operating con-ditions, the exploitation of the adherence value at the front and rear axles, that is theoretically possible, will not be attained.
It is, therefore, an object of the invention to overcome the afore-mentioned disadvantages involved with the prior art systems and to improve the brake force distribution in auto-motive vehicles such that both in the extreme "unloaded/loaded"conditions and in every braking operation of the vehicle, the brake force distribution will be adapted in close approximation to the actual static and dynamic axle load distribution thereby attaining an optimum brake function, i.e. road stability, short stopping distance and a uniform load on the two axles. More-over, high importance has been attached to meeting the require ments of comparatively low effort in the manufacture and assem-bly of the brake system.
The invention provides a pumpless hydraulic fluid pressure distributor control for automotive vehicles having a hydraulic brake system with two front brake assemblies and two rear brake assemblies hydraulically connected to a tandem master cylinder pressure source, said control comprising: sensors for gener-ating electric signals proportional to wheel rotation character-istics at a front axle and at a rear axle of the vehicle; an electronic circuit for combining, processing and evaluating the sensor signals for generating control signals therefrom; at least one control valve slip modulator connected between said pressure source and said rear brake assemblies for controlling the brake pressure at the rear axle in response to said control signals; and, at least one control valve lock modulator oper-~' .
129L81~L
- 3a -atively coupled between said pressure source and said rear bra]ce assemblies to decrease the pressure at the rear axle in response to electric signals indicative of a tendency to lock said rear brake assemblies; whereby said slip modulator is normally closed and opens in response to said control signals thereby ensuring that said rear axle is braked at a rate not greater than said front axle by braking said rear axle following in time braking of said front axle, and said lock modulator ensures that said rear axle is not locked.
The invention is based on the consideration that by measuring the wheel and vehicle velocities and the time-responsive changes in the said measured variables, respectively, by processing the said measured values to form a control signal in an electronic circuit, e.g. in a microprocessor, and by using simple control valves as pressure modulators, a brake force distributor can be realized which, under consideration of the conditions actually prevailing at the .~
1~481l61 !
time of the brake operation, inclusive of the road conditions, condition of the brake system, static and dynamic axle load distribution etc., in almost ideal manner distributes the brake force onto the front and rear wheels thereby, above all, attaining a short stopping distance, a low locking risk and, hence, a high road stability and a uniform load of the braking system. Owing to the fact that only in exceptional cases, the pressure on the rear axle is required to be decreased, also the relatively rare driving situations caused e.g. by rapidly changing road conditions, will be taken into account. FOI~ in such situations, after attaining an initially proper wheel cylinder pressure and a constantly maintained braking pressure, a wheel blocking on the rear axle could subsequently occur. As opposed to brake slip control systems, in the brake force distrihutor sf the present invention, no renewed brake pressure build-up will occur withln a braking operation; and in contrast to brake slip control systems,no external eneryy supply, for rehuilding the brake pressure, as a rule, is required. In the light of the required manufacturing efforts for the brake system and the operational safety thereof, this will be of a special importance.
Further advantages and applicabilities of the invention will oecome obvious from the following description nf details and of embodiments of this invention.
., In the drawings:
.., ' Fig. 1 is a schematically~simplified block diagram of an embodiment of the brake force distributar according to the invention for a double-circuit brake system having a diagnnal oraking force split-op;
lZ4~3161 Flg. Z is the diagram of the time-responsive curve of pressure when using the brake force distributor Df the invention;
F~g. 3 is, alike the illustration of Fig. 1, a form of embodiment of a double-circuit brake system with respectively one brake circuit for the front axle and ~or the rear axle.
In the douole~circuit brake system according to Fig. 1, the brake circuitsare diagonally split. In a standard construction-type tandem master cylinder 1 as symbolically shown, nn which as symbolized oy the arrow - trake force F is exerted vla a pedal, the lefthand front wheel VRl End the righthand rear wheel HRr are connected to a brake circuit Z. The second brake circuit 3 will act upon the t~o other wheels VRr and HRl.
In the illustrated form of embodiment of the invention, the pressure modulatQrs are quick-acting, two-way, two-position valves 4,5,6. ~hile the two front wheels are directly connected to the associated braking circuit 2 and 3, respectively, of the tandem master cylinDer 1; a pressure build-up on the rear wheels will be possiblE only after the two control valves 4,5 being energizeo.
Activation of these valves is effected via an electronic control 7, to which measured variables generated with the aid of sensors 8,9 and ~0 are fed via signal lines ~', 9~, 10~ in the form of elecbric signals and which, by a logic combination, will compute the required cuntrol signal and will control the brake pressure modulators. Control 7 may contain e~g. a microprocessor for processing the sensor signals and for generating the control signals.
~ . ., . . , . . ~ . . ... .
In the form of embodiment as described here,- by sensor ~, an average value cv~R of the wheel speed at the front axle i9 determined; by sensor 10, an average value ~vHR of the wheel speeds at the rear axle is determined; and by sensor 9, the transla$ory deceleration -b of the vehicle during the braking operation, or measured values proportional to the wheel speeds and the deceleration, respectively, are determined. If the vehicle ls already equipped with an electronic sensor for the speedometer the same may, at the sa~e time, be used for generating the measured variable ~VR
The pressure curve PHA on the rear axle generated with the aid Df the modulators and control valves 4757 respectively7 and the brake pressure cur~e P~Q on the front axle on which PHA i9 dependent, i9 illustrated by FigO 2. In that example of embodiment, control 7 will generate - laterally delayed over the rise in the front axle pressure PVA - activation pulses for control valves 4,5, with the pressure rise PHA required for an ideal pressure distribution, being adjusted at the rear wheel3 by pulsating or clock controlled reswitching of valves 4,5 from the (shown) clnsing position into the through-flow position.
Moreover, in accordance with the invention, another two-way, two position valve 6 i9 provided for decreasing the rear wheel pressure.
6y hydraulically connecting the two rear wheel circuits via a line having two series connected and oppositeIy directed non-return valves 11,12, a single two-way, two-position valve 6 will be sufficient for the pressure decrease in the two rear wheel circuits. The illustration of Fig. 1 conveys that via the electrical connection o~ the electronic control 7 leading to the operating magnet of valve 6, the normally closed two-way, two-position valve 6 for the pressure decrease can be reswitched into the through-flow position whereupon both rear wheel circuits via the non-return ,"i - 7 - ~
valves 11,1Z are connected to the pressure cDmpensating unit 13 being part of the brake system.
As sho~n in Fig. Z, the pressure, as soon as a locking tendency is indicated, is stepwise reduced to a lower value at which the brake slip at the rear axle corresponds to the brake slip at the front axle or lags beh1nd the same. The pressure decrease starts at a time t after control 7 having detected a locking tendency at the rear wheels at the time to by comparing the wheel deceleration at the rear axle with the vehicle deceleration.
Non-return valves 14,15 provided in parallel to the pressure build-up valves 4,5 ~ill accelerate the decrease in the brake pressure ~hen releasing the brake.
In a double-circuit hrake split-up in which one circuit acts upon the front axle, while the other circuit acts upon the rear axle, the brake force distributor according to the invention ~ill require a still smaller numoer of components. As sho~n in Fig. 3, respectively nne electromagnetically operated two-way, two-position valve 16 and 17, will be sufficient for the build-up Df the braking pressure at the rear axle and for the pressure reduction released as soon as control 7'~has concluded a locking tendency of the rear wheels from the sensor signals fed to it via signal lines 8',9',10'. The non-return valves 11,12 disposed in the embodiment according to Fig. 1 in the feedline to the pressure reducing valve 6, are eliminated in the embodiment according to Fig. 3.
Fig. 1, moreover, sho~s a difference pressure switch 18 signalizing failure of a brake circuit and a pressure difference caused thereby between the twn brake circuits Z,3, to control 7 via line 19. This will cause a permanent energization of valves 4,5 and a permanent locking of valve 6 in order that upon failure of a brake circuit, at least in the second brake circuit, the full brake pressure can be built up on the front and rear axles~ The track or directional stability ~2~8~6~
. ~
of the vehicle, in that case, will al50 be maintained with a locking of the wheels of the intact diagonal circoit by the non-braked wheels of the failing oraking circuit.
:
1.
:`
: :
I
It iB a oisadvantage of such a brake force distributor that the value of adherence between road and wheel at the rear and front axles actually prevailing at the time of the braking operation and depending on numerous parametPrs, cannot exert an influence on the brake force distribution. For this reason, it i5 imperative for the brake, in order to safely avoid the dangerous overbraklng of the rear axle, to oe so designed that in the ma~ority of cases, the rear axle wlll cuntribute little to the braking operation.
Moreover, lt has proved to bP disadvantageous that the actual values in practice considerably differ from the numerically calculated should-be values. The brake characteristics assumed to be constant in the layout of ~he braking force distribution and the memorized mathematical expressian, in practice, are subject to substantial changes, e.g. as a result of manufacturing tolerances in the coefficient of friction, aging, contamination, changes in the spring constant in operation, defective adjustment, heavy temperature changes etc~ ~11 this might result in that the actual characteristic of the brake force distribution considerably differes from the precalculated values.
ThP brake force distributors commonly used nowadays are limited to an invariaoly adjusted pressure-responsive contrnl. Load-responsive or decelearation~responsive brake force regulators are likewise known in a great number of variants. For the afore-going reasons, even when maklng great assembly and adjustment ~z~
~ - 3 -efforts, a satisfactory adaptation can be attained with these prior art devices, at best, in one of the two extreme "unloaded/
loaded" conditions so that, in a multiplicity of operating con-ditions, the exploitation of the adherence value at the front and rear axles, that is theoretically possible, will not be attained.
It is, therefore, an object of the invention to overcome the afore-mentioned disadvantages involved with the prior art systems and to improve the brake force distribution in auto-motive vehicles such that both in the extreme "unloaded/loaded"conditions and in every braking operation of the vehicle, the brake force distribution will be adapted in close approximation to the actual static and dynamic axle load distribution thereby attaining an optimum brake function, i.e. road stability, short stopping distance and a uniform load on the two axles. More-over, high importance has been attached to meeting the require ments of comparatively low effort in the manufacture and assem-bly of the brake system.
The invention provides a pumpless hydraulic fluid pressure distributor control for automotive vehicles having a hydraulic brake system with two front brake assemblies and two rear brake assemblies hydraulically connected to a tandem master cylinder pressure source, said control comprising: sensors for gener-ating electric signals proportional to wheel rotation character-istics at a front axle and at a rear axle of the vehicle; an electronic circuit for combining, processing and evaluating the sensor signals for generating control signals therefrom; at least one control valve slip modulator connected between said pressure source and said rear brake assemblies for controlling the brake pressure at the rear axle in response to said control signals; and, at least one control valve lock modulator oper-~' .
129L81~L
- 3a -atively coupled between said pressure source and said rear bra]ce assemblies to decrease the pressure at the rear axle in response to electric signals indicative of a tendency to lock said rear brake assemblies; whereby said slip modulator is normally closed and opens in response to said control signals thereby ensuring that said rear axle is braked at a rate not greater than said front axle by braking said rear axle following in time braking of said front axle, and said lock modulator ensures that said rear axle is not locked.
The invention is based on the consideration that by measuring the wheel and vehicle velocities and the time-responsive changes in the said measured variables, respectively, by processing the said measured values to form a control signal in an electronic circuit, e.g. in a microprocessor, and by using simple control valves as pressure modulators, a brake force distributor can be realized which, under consideration of the conditions actually prevailing at the .~
1~481l61 !
time of the brake operation, inclusive of the road conditions, condition of the brake system, static and dynamic axle load distribution etc., in almost ideal manner distributes the brake force onto the front and rear wheels thereby, above all, attaining a short stopping distance, a low locking risk and, hence, a high road stability and a uniform load of the braking system. Owing to the fact that only in exceptional cases, the pressure on the rear axle is required to be decreased, also the relatively rare driving situations caused e.g. by rapidly changing road conditions, will be taken into account. FOI~ in such situations, after attaining an initially proper wheel cylinder pressure and a constantly maintained braking pressure, a wheel blocking on the rear axle could subsequently occur. As opposed to brake slip control systems, in the brake force distrihutor sf the present invention, no renewed brake pressure build-up will occur withln a braking operation; and in contrast to brake slip control systems,no external eneryy supply, for rehuilding the brake pressure, as a rule, is required. In the light of the required manufacturing efforts for the brake system and the operational safety thereof, this will be of a special importance.
Further advantages and applicabilities of the invention will oecome obvious from the following description nf details and of embodiments of this invention.
., In the drawings:
.., ' Fig. 1 is a schematically~simplified block diagram of an embodiment of the brake force distributar according to the invention for a double-circuit brake system having a diagnnal oraking force split-op;
lZ4~3161 Flg. Z is the diagram of the time-responsive curve of pressure when using the brake force distributor Df the invention;
F~g. 3 is, alike the illustration of Fig. 1, a form of embodiment of a double-circuit brake system with respectively one brake circuit for the front axle and ~or the rear axle.
In the douole~circuit brake system according to Fig. 1, the brake circuitsare diagonally split. In a standard construction-type tandem master cylinder 1 as symbolically shown, nn which as symbolized oy the arrow - trake force F is exerted vla a pedal, the lefthand front wheel VRl End the righthand rear wheel HRr are connected to a brake circuit Z. The second brake circuit 3 will act upon the t~o other wheels VRr and HRl.
In the illustrated form of embodiment of the invention, the pressure modulatQrs are quick-acting, two-way, two-position valves 4,5,6. ~hile the two front wheels are directly connected to the associated braking circuit 2 and 3, respectively, of the tandem master cylinDer 1; a pressure build-up on the rear wheels will be possiblE only after the two control valves 4,5 being energizeo.
Activation of these valves is effected via an electronic control 7, to which measured variables generated with the aid of sensors 8,9 and ~0 are fed via signal lines ~', 9~, 10~ in the form of elecbric signals and which, by a logic combination, will compute the required cuntrol signal and will control the brake pressure modulators. Control 7 may contain e~g. a microprocessor for processing the sensor signals and for generating the control signals.
~ . ., . . , . . ~ . . ... .
In the form of embodiment as described here,- by sensor ~, an average value cv~R of the wheel speed at the front axle i9 determined; by sensor 10, an average value ~vHR of the wheel speeds at the rear axle is determined; and by sensor 9, the transla$ory deceleration -b of the vehicle during the braking operation, or measured values proportional to the wheel speeds and the deceleration, respectively, are determined. If the vehicle ls already equipped with an electronic sensor for the speedometer the same may, at the sa~e time, be used for generating the measured variable ~VR
The pressure curve PHA on the rear axle generated with the aid Df the modulators and control valves 4757 respectively7 and the brake pressure cur~e P~Q on the front axle on which PHA i9 dependent, i9 illustrated by FigO 2. In that example of embodiment, control 7 will generate - laterally delayed over the rise in the front axle pressure PVA - activation pulses for control valves 4,5, with the pressure rise PHA required for an ideal pressure distribution, being adjusted at the rear wheel3 by pulsating or clock controlled reswitching of valves 4,5 from the (shown) clnsing position into the through-flow position.
Moreover, in accordance with the invention, another two-way, two position valve 6 i9 provided for decreasing the rear wheel pressure.
6y hydraulically connecting the two rear wheel circuits via a line having two series connected and oppositeIy directed non-return valves 11,12, a single two-way, two-position valve 6 will be sufficient for the pressure decrease in the two rear wheel circuits. The illustration of Fig. 1 conveys that via the electrical connection o~ the electronic control 7 leading to the operating magnet of valve 6, the normally closed two-way, two-position valve 6 for the pressure decrease can be reswitched into the through-flow position whereupon both rear wheel circuits via the non-return ,"i - 7 - ~
valves 11,1Z are connected to the pressure cDmpensating unit 13 being part of the brake system.
As sho~n in Fig. Z, the pressure, as soon as a locking tendency is indicated, is stepwise reduced to a lower value at which the brake slip at the rear axle corresponds to the brake slip at the front axle or lags beh1nd the same. The pressure decrease starts at a time t after control 7 having detected a locking tendency at the rear wheels at the time to by comparing the wheel deceleration at the rear axle with the vehicle deceleration.
Non-return valves 14,15 provided in parallel to the pressure build-up valves 4,5 ~ill accelerate the decrease in the brake pressure ~hen releasing the brake.
In a double-circuit hrake split-up in which one circuit acts upon the front axle, while the other circuit acts upon the rear axle, the brake force distributor according to the invention ~ill require a still smaller numoer of components. As sho~n in Fig. 3, respectively nne electromagnetically operated two-way, two-position valve 16 and 17, will be sufficient for the build-up Df the braking pressure at the rear axle and for the pressure reduction released as soon as control 7'~has concluded a locking tendency of the rear wheels from the sensor signals fed to it via signal lines 8',9',10'. The non-return valves 11,12 disposed in the embodiment according to Fig. 1 in the feedline to the pressure reducing valve 6, are eliminated in the embodiment according to Fig. 3.
Fig. 1, moreover, sho~s a difference pressure switch 18 signalizing failure of a brake circuit and a pressure difference caused thereby between the twn brake circuits Z,3, to control 7 via line 19. This will cause a permanent energization of valves 4,5 and a permanent locking of valve 6 in order that upon failure of a brake circuit, at least in the second brake circuit, the full brake pressure can be built up on the front and rear axles~ The track or directional stability ~2~8~6~
. ~
of the vehicle, in that case, will al50 be maintained with a locking of the wheels of the intact diagonal circoit by the non-braked wheels of the failing oraking circuit.
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Claims (3)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A pumpless hydraulic fluid pressure distributor con-trol for automotive vehicles having a hydraulic brake system with two front brake assemblies and two rear brake assemblies hydraulically connected to a tandem master cylinder pressure source, said control comprising:
sensors for generating electric signals proportional to wheel rotation characteristics at a front axle and at a rear axle of the vehicle;
an electronic circuit for combining, processing and evaluating the sensor signals for generating control signals therefrom;
at least one control valve slip modulator connected between said pressure source and said rear brake assemblies for controlling the brake pressure at the rear axle in response to said control signals; and, at least one control valve lock modulator operatively coupled between said pressure source and said rear brake assem-blies to decrease the pressure at the rear axle in response to electric signals indicative of a tendency to lock said rear brake assemblies;
whereby said slip modulator is normally closed and opens in response to said control signals thereby ensuring that said rear axle is braked at a rate not greater than said front axle by braking said rear axle following in time braking of said front axle, and said lock modulator ensures that said rear axle is not locked.
sensors for generating electric signals proportional to wheel rotation characteristics at a front axle and at a rear axle of the vehicle;
an electronic circuit for combining, processing and evaluating the sensor signals for generating control signals therefrom;
at least one control valve slip modulator connected between said pressure source and said rear brake assemblies for controlling the brake pressure at the rear axle in response to said control signals; and, at least one control valve lock modulator operatively coupled between said pressure source and said rear brake assem-blies to decrease the pressure at the rear axle in response to electric signals indicative of a tendency to lock said rear brake assemblies;
whereby said slip modulator is normally closed and opens in response to said control signals thereby ensuring that said rear axle is braked at a rate not greater than said front axle by braking said rear axle following in time braking of said front axle, and said lock modulator ensures that said rear axle is not locked.
2. A control according to claim 1, wherein the or each modulator comprises a quick-acting, electromagnetically operated two-way, two-position valve that, in energized condition, con-nect a rear wheel, and one rear wheel braking cylinder to a pressure compensating unit and that, in de-energized condition, block the passage.
3. A control as claimed in claim 1, for an automotive vehicle having a hydraulic brake system and a diagonal brake circuit split-up, characterized in that the hydraulic brake circuits of the two rear wheels are connected to a common electromagnetically operated two-way, two-position valve serving as a modulator for the pressure decrease, which will be blocked when de-energized and which will establish a connection with a pressure compensating unit when energized, with a non-return valve being respectively provided in the path to the two-way, two-position valve for decoupling the two hydraulic braking circuits.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19833306611 DE3306611A1 (en) | 1983-02-25 | 1983-02-25 | METHOD AND DEVICE FOR CONTROLLING THE BRAKING DISTRIBUTION |
| DEP3306611.6 | 1983-02-25 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1248161A true CA1248161A (en) | 1989-01-03 |
Family
ID=6191795
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000448208A Expired CA1248161A (en) | 1983-02-25 | 1984-02-24 | Method and device for controlling the distribution of brake force |
Country Status (8)
| Country | Link |
|---|---|
| JP (1) | JPS59192659A (en) |
| BR (1) | BR8400635A (en) |
| CA (1) | CA1248161A (en) |
| DE (1) | DE3306611A1 (en) |
| FR (1) | FR2541642B1 (en) |
| GB (1) | GB2135413B (en) |
| IT (1) | IT1173337B (en) |
| SE (1) | SE456984B (en) |
Families Citing this family (35)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3323402A1 (en) * | 1983-04-07 | 1984-10-18 | Alfred Teves Gmbh, 6000 Frankfurt | BRAKE SYSTEM FOR MOTOR VEHICLES |
| DE3425672C2 (en) * | 1984-07-12 | 1994-07-28 | Teves Gmbh Alfred | Brake system for motor vehicles |
| DE3429156C2 (en) * | 1984-08-08 | 1994-06-23 | Teves Gmbh Alfred | Circuit arrangement for monitoring and controlling an anti-lock brake system |
| DE3434512A1 (en) * | 1984-09-20 | 1986-03-27 | Ingo 4500 Osnabrück Remmert | ELECTRICAL CONTROL DEVICE FOR AN ELECTROMAGNETIC BRAKE OF A VEHICLE TRAILER |
| US4790607A (en) * | 1985-02-19 | 1988-12-13 | Kelsey Hayes Company | Vehicle anti-lock brake system |
| JPS6246751A (en) * | 1985-08-27 | 1987-02-28 | Japan Radio Co Ltd | Brake device for suppressing wheel slip |
| JPH0629007B2 (en) * | 1985-11-19 | 1994-04-20 | 曙ブレーキ工業株式会社 | Vehicle anti-lock system |
| DE3542417C2 (en) * | 1985-11-30 | 1994-11-24 | Teves Gmbh Alfred | Arrangement for an anti-lock brake system |
| DE3602432A1 (en) * | 1986-01-28 | 1987-07-30 | Bosch Gmbh Robert | ANTI-BLOCKING CONTROL SYSTEM |
| DE3745189B4 (en) * | 1986-07-04 | 2005-08-25 | Denso Corp., Kariya | Braking force control for motor vehicle - has sensors coupled to processor controlling braking pressure at wheels independently |
| DE3722107B4 (en) * | 1986-07-04 | 2005-09-08 | Denso Corp., Kariya | Braking force control for motor vehicle - has sensors coupled to processor controlling braking pressure at wheels independently |
| DE3643141A1 (en) * | 1986-12-17 | 1988-07-07 | Teves Gmbh Alfred | BRAKE SYSTEM FOR MOTOR VEHICLES |
| DE3901923A1 (en) * | 1989-01-24 | 1990-09-13 | Bosch Gmbh Robert | ELECTRONICALLY CONTROLLED BRAKE POWER DISTRIBUTOR |
| JPH03159855A (en) * | 1989-11-16 | 1991-07-09 | Aisin Seiki Co Ltd | Anti-skid control device |
| DE4036940A1 (en) * | 1990-02-17 | 1991-08-22 | Bosch Gmbh Robert | BRAKE SYSTEM FOR A VEHICLE |
| DE4015747C2 (en) * | 1990-05-16 | 2000-08-03 | Continental Teves Ag & Co Ohg | Brake system for motor vehicles with electronically controlled brake force distribution and with anti-lock control |
| DE4112388A1 (en) * | 1991-04-16 | 1992-10-22 | Bosch Gmbh Robert | BRAKE PRESSURE CONTROL SYSTEM FOR A VEHICLE |
| DE4128087A1 (en) * | 1991-08-24 | 1993-02-25 | Bosch Gmbh Robert | BRAKE PRESSURE CONTROL SYSTEM FOR A VEHICLE |
| US5236252A (en) * | 1991-12-18 | 1993-08-17 | Alliedsignal Inc. | Method of skid dection without speed sensors |
| DE4203671A1 (en) * | 1992-02-08 | 1993-08-12 | Teves Gmbh Alfred | HYDRAULIC BRAKE SYSTEM WITH SLIP CONTROL |
| DE4224971A1 (en) * | 1992-07-29 | 1994-02-03 | Teves Gmbh Alfred | Method for increasing the functional reliability of a brake system with electronic control of the brake force distribution |
| DE4243668C2 (en) * | 1992-12-23 | 2003-01-23 | Bosch Gmbh Robert | Brake system for a motor vehicle |
| DE4309243C2 (en) * | 1993-03-23 | 2003-07-03 | Continental Teves Ag & Co Ohg | Brake system with electronic control of the brake force distribution |
| JP2895760B2 (en) * | 1994-05-02 | 1999-05-24 | 日本エービーエス株式会社 | Hydraulic pressure control method for anti-skid device for vehicle |
| DE4417935A1 (en) * | 1994-05-21 | 1995-11-23 | Teves Gmbh Alfred | Circuit arrangement for a brake system with electronic control of the brake force distribution |
| DE4424317C2 (en) * | 1994-07-09 | 2003-11-13 | Bosch Gmbh Robert | Anti-lock control system |
| DE19510746A1 (en) * | 1995-03-24 | 1996-09-26 | Bosch Gmbh Robert | Method and device for controlling the brake system of a vehicle |
| DE19511161A1 (en) * | 1995-03-27 | 1996-10-02 | Bosch Gmbh Robert | Brake system for a motor vehicle |
| DE19511162A1 (en) * | 1995-03-27 | 1996-10-02 | Bosch Gmbh Robert | Brake system for a motor vehicle |
| DE19614908A1 (en) * | 1996-04-16 | 1997-10-23 | Teves Gmbh Alfred | Brake system with electronic brake force distribution |
| DE19651460A1 (en) * | 1996-12-11 | 1998-06-18 | Bosch Gmbh Robert | Method and device for controlling the brake force distribution in a vehicle |
| WO1998039187A1 (en) | 1997-03-04 | 1998-09-11 | Kelsey Hayes Company | Electronic rear brake proportioning system |
| US6241326B1 (en) | 1998-10-28 | 2001-06-05 | Kelsey-Hayes Company | Electronic brake proportioning for a rear wheel anti-lock brake system |
| US7809486B2 (en) | 2005-04-29 | 2010-10-05 | Kelsey-Hayes Company | Pressure boost for vehicle rear brake circuits |
| DE102009046942A1 (en) | 2009-11-20 | 2011-05-26 | Robert Bosch Gmbh | Method for operating a brake system and corresponding control device |
Family Cites Families (17)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1185354A (en) * | 1966-06-15 | 1970-03-25 | North American Rockwell | Fluid Pressure Brake Systems |
| JPS5039232B1 (en) * | 1969-11-12 | 1975-12-15 | ||
| FR2067882A5 (en) * | 1969-11-20 | 1971-08-20 | Dba | |
| US3608978A (en) * | 1970-05-01 | 1971-09-28 | Rockwell Standard Co | Antiskid brake control |
| US3701568A (en) * | 1970-09-30 | 1972-10-31 | Bendix Corp | Adaptive braking system utilizing doppler radar |
| FR2168226B1 (en) * | 1972-01-21 | 1974-05-10 | Dba | |
| FR2201995B1 (en) * | 1972-06-13 | 1976-10-29 | Citroen Sa | |
| ZA738692B (en) * | 1972-12-14 | 1974-09-25 | Kelsey Hayes Co | Four-wheel skid control |
| DE2307623A1 (en) * | 1973-02-16 | 1974-08-29 | Bosch Gmbh Robert | ANTI-LOCK CONTROL SYSTEM FOR PRESSURE-CONTROLLED MOTOR VEHICLE BRAKES |
| DE2433092C2 (en) * | 1974-07-10 | 1986-10-23 | Robert Bosch Gmbh, 7000 Stuttgart | Anti-lock control system for four-wheel vehicles |
| DE2812000A1 (en) * | 1978-03-18 | 1979-09-27 | Bosch Gmbh Robert | ANTI-LOCK CONTROL SYSTEM |
| DE2830809A1 (en) * | 1978-07-13 | 1980-01-31 | Bosch Gmbh Robert | ANTI-BLOCKING CONTROL SYSTEM |
| DE2913424A1 (en) * | 1979-04-04 | 1980-10-16 | Bosch Gmbh Robert | ANTI-BLOCKING DEVICE |
| DE3109372A1 (en) * | 1981-03-12 | 1982-09-30 | Volkswagenwerk Ag, 3180 Wolfsburg | "PUMPLESS HYDRAULIC BRAKE SYSTEM FOR MOTOR VEHICLES" |
| IT1143485B (en) * | 1981-04-03 | 1986-10-22 | Ettore Cordiano | BRAKING SYSTEM FOR VEHICLES WITH BRAKE DISTRIBUTOR CONTROLLED BY ELECTRONIC PROCESSOR |
| DE3136617A1 (en) * | 1981-09-15 | 1983-03-31 | Alfred Teves Gmbh, 6000 Frankfurt | Braking wheel slip control system for the wheel brakes of a vehicle |
| DE3301948A1 (en) * | 1983-01-21 | 1984-07-26 | Alfred Teves Gmbh, 6000 Frankfurt | METHOD AND DEVICE FOR CONTROLLING THE BRAKING DISTRIBUTION |
-
1983
- 1983-02-25 DE DE19833306611 patent/DE3306611A1/en not_active Ceased
-
1984
- 1984-02-10 GB GB08403514A patent/GB2135413B/en not_active Expired
- 1984-02-14 BR BR8400635A patent/BR8400635A/en not_active IP Right Cessation
- 1984-02-17 FR FR8402447A patent/FR2541642B1/en not_active Expired
- 1984-02-22 IT IT19743/84A patent/IT1173337B/en active
- 1984-02-22 SE SE8400965A patent/SE456984B/en not_active IP Right Cessation
- 1984-02-24 JP JP59034126A patent/JPS59192659A/en active Pending
- 1984-02-24 CA CA000448208A patent/CA1248161A/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| DE3306611A1 (en) | 1984-08-30 |
| SE8400965L (en) | 1984-08-26 |
| SE456984B (en) | 1988-11-21 |
| GB2135413B (en) | 1987-02-04 |
| GB8403514D0 (en) | 1984-03-14 |
| GB2135413A (en) | 1984-08-30 |
| SE8400965D0 (en) | 1984-02-22 |
| JPS59192659A (en) | 1984-11-01 |
| FR2541642B1 (en) | 1989-11-17 |
| IT1173337B (en) | 1987-06-24 |
| FR2541642A1 (en) | 1984-08-31 |
| BR8400635A (en) | 1984-10-02 |
| IT8419743A0 (en) | 1984-02-22 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |