GB2293867A - Hydraulic braking systems of the brake-by-wire type - Google Patents

Hydraulic braking systems of the brake-by-wire type Download PDF

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Publication number
GB2293867A
GB2293867A GB9520530A GB9520530A GB2293867A GB 2293867 A GB2293867 A GB 2293867A GB 9520530 A GB9520530 A GB 9520530A GB 9520530 A GB9520530 A GB 9520530A GB 2293867 A GB2293867 A GB 2293867A
Authority
GB
United Kingdom
Prior art keywords
braking system
actuator
brake
pump
demand
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.)
Granted
Application number
GB9520530A
Other versions
GB9520530D0 (en
GB2293867B (en
Inventor
Robert Alan Anderson
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
ZF International UK Ltd
Original Assignee
Lucas Industries Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Lucas Industries Ltd filed Critical Lucas Industries Ltd
Publication of GB9520530D0 publication Critical patent/GB9520530D0/en
Publication of GB2293867A publication Critical patent/GB2293867A/en
Application granted granted Critical
Publication of GB2293867B publication Critical patent/GB2293867B/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

Links

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
    • B60T8/32—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration
    • B60T8/34—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration having a fluid pressure regulator responsive to a speed condition
    • B60T8/36—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration having a fluid pressure regulator responsive to a speed condition including a pilot valve responding to an electromagnetic force
    • B60T8/3615—Electromagnetic valves specially adapted for anti-lock brake and traction control systems
    • B60T8/3655—Continuously controlled electromagnetic valves
    • B60T8/366—Valve details
    • B60T8/367—Seat valves, e.g. poppet valves
    • 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
    • B60T13/00—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems
    • B60T13/10—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems with fluid assistance, drive, or release
    • B60T13/66—Electrical control in fluid-pressure brake systems
    • B60T13/68—Electrical control in fluid-pressure brake systems by electrically-controlled valves
    • B60T13/686—Electrical control in fluid-pressure brake systems by electrically-controlled valves in hydraulic systems or parts thereof
    • 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
    • B60T13/00—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems
    • B60T13/74—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems with electrical assistance or drive
    • B60T13/745—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems with electrical assistance or drive acting on a hydraulic system, e.g. a master cylinder
    • 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
    • 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
    • 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
    • B60T8/32—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration
    • B60T8/34—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration having a fluid pressure regulator responsive to a speed condition
    • B60T8/40—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration having a fluid pressure regulator responsive to a speed condition comprising an additional fluid circuit including fluid pressurising means for modifying the pressure of the braking fluid, e.g. including wheel driven pumps for detecting a speed condition, or pumps which are controlled by means independent of the braking system
    • B60T8/404—Control of the pump unit
    • B60T8/4059—Control of the pump unit involving the rate of delivery

Description

1 IMPROVEMENTS IN HYDRAULIC BRAKING SYSTEMS OF THE BRAKE-BY-WIRE TYPE WI
2293 v & This invention relates to hydraulic braking systems of the brake-by-wire type of the kind in which an electrical signal from a pedal-operated transducer is adapted to operate a solenoid- operated actuator in turn to control the supply of hydraulic fluid to a wheel brake.
Normally in known hydraulic systems of the kind set forth the magnitude of the brake applying pressure is determined by operation of the actuator itself which controls communication between a pressure source and a reservoir for fluid, normally closing a return passageway to a reservoir when the brake is applied. In such a system a complex arrangement of control valves is required in order to maintain the pressure of the brakeapplying fluid at a desired operational level.
According to our invention in an hydraulic braking system of the brake-bywire type of the kind set forth the actuator is adapted to act as a pressure relief valve to return to a lower pressure reservoir any in excess of a desired pressure for a given brake application.
The actuator may comprise a proportional solenoid -operated valve responsive to a demand signal to control communication in an open-centre manner between the high pressure source, the brake and the lower pressure reservoir.
When the high pressure source comprises a motor driven hydraulic pump, and the speed and therefore the output, of the pump are controlled in accordance with 2 demand, the actuator acts to reduce the pressure by relieving it to the reservoir, should the pressure exceed the required value for a given demand.
Preferably the speed of the motor and the output of the pump are determined by demand modified or adjusted so as to be compensated for dynamic changes in the vehicle such as weight transfer or operating gradient.
optionally when there is no demand, the motor driving the pump is adapted to turn over gently.
In one particular construction the signal generated by displacement of the pedal is fed to an electronic control unit which emits energising current to operate both the actuator and the electric motor for driving the pump so that the actuator and the motor are operated in synchronism.
A solenoid- operated armature of the actuator may operate a cut-off valve comprising a valve head which is adapted to be urged against a seating surrounding an opening in a housing against a force in a return spring, the opening being connected to the high pressure source, and an exhaust port in the housing being connected to a return line to the reservoir.
Preferably the valve member comprises a ball for engagement with seating which may be of complementary part-spherical outline.
One embodiment of our invention is illustrated in the single Figure of the accompanying drawings which illustrates a layout of an hydraulic braking system of the brake-by-wire type.
3 In the braking system illustrated in the drawings a pedal 1 is adapted to operate a pair of travel transducers 2 and 3 arranged In tandem. In a modification the travel transducers can be replaced by force sensors. The output from the transducer 2 is fed into an electronic control unit 4, and the output from the travel transducer 3 is fed into an electronic control unit 5.
The travel transducer 2 and the electronic control unit 4 are incorporated into a first braking circuit for applying a brake 6 on the front right wheel 7 of a vehicle and a brake 8 on the rear left wheel 9 of the vehicle. Similarly the travel transducer 3 and the electronic control unit 5 are incorporated into a second circuit for operating a brake 10 on the front left wheel 11 of the vehicle and a brake 12 on the rear right wheel 13 of the vehicle.
Each braking circuit includes a low pressure reservoir 14 from which a pump 15 is adapted to draw fluid through one-way inlet valves 16 and pump it directly to the respective brakes 6, 8 and 10, 12 through one-way outlet valves 17. The pump 15 is adapted to be driven by an electric motor 18 which is powered by a battery supply 19 under the control of the respective electronic control unit 4 or 5.
An actuator 20 is installed between each brake 6 and 8 and a return line 21 to the reservoir 14, and between each brake 10 and 12 and a return line 22 to the respective reservoir 14.
Each actuator comprises a proportional sol enoid- operated valve. Each solenoid -operated valve comprises a housing 23 in which is incorporated a 4 armature 24 and a solenoid coil (not shown). The armature 24 movable in the housing 23 upon energisation of the coil is adapted to control operation of a variable pressure relief valve 25, movement of the armature being proportional to the magnitude of the energising current. As illustrated the relief valve 25 comprises a valve member 26 of thimblelike outline into which the armature 24 extends and the valve member 26 is mounted in a bore 28 in an extension 29 of the housing with a working clearance. Normally the valve member 26 is held, at its open end, against a stop face 27 by the force in a compression return spring 30. In this position a ball 31 carried by the closed end of the valve member 26 is spaced from a seating 32 surrounding an axial passage 33 in the housing extension 29 and which is connected to the respective brake. The return line 21 to the reservoir 14 is connected to a chamber 34 between the valve member 26 and the adjacent end of the bore 28 through a radial passage 35 in the wall of the extension 29.
In the inoperative, brakes-off, position illustrated in the drawings the ball 31 is spaced from the seating 32, which may be of complementary partspherical outline, so that free, unrestricted, communication is provided between the brake and its respective reservoir 14.
When the pedal 1 is actuated to operate the braking system each electronic control unit 4, 5 energises its respective motor 15 and energises the coils of each of the four actuators 20. The armatures 24 move forward to close the relief valves 25 so that the brakes are applied by the application of pressure from the pumps and through the outlet valves 17.
The speed of the motor 15 and the outputs from the pump are normally determined by demand modified or adjusted so as to be compensated for dynamic changes in the vehicle such as weight transfer or operating gradient. However, should the pressure applied to a brake exceed that required to achieve a desired level of braking, then the electronic control unit for that brake reduces the energising current which allows the respective relief valve to open and relieve excess pressure directly to the respective reservoir 14.
Each actuator therefore operates in an open-centre manner.
At the termination of a braking cycle when the pedal is released so that driver's braking demand ceases, the motor 18 stops and the variable pressure relief valves 25 open to release the braking pressure to the reservoirs 14.
6

Claims (10)

1. An hydraulic braking system of the brake-by-wire type of the kind set forth in which the actuator is adapted to act as a pressure relief valve to return to a lower pressure reservoir any fluid in excess of a desired pressure for a given brake application.
2. A braking system as claimed in claim 1, in which the actuator comprises a proportional solenoid-operated valve responsive to a demand signal to control communication in an open-centre manner between the high pressure source, the brake and the low pressure reservoir.
3. A braking system as claimed in claim 1 or claim 2, in which the high pressure source comprises a motor driven hydraulic pump, and the speed and output of the pump are controlled in accordance with demand, the actuator acting to reduce the pressure by relieving it to the reservoir, should the pressure exceed the required value for a given demand.
4. A braking system as claimed in claim 3, in which the speed of the motor and the output of the pump are determined by demand modified or adjusted so as to be compensated for dynamic changes in the vehicle.
5. A braking system as claimed in claim 3, in which when there is no demand, the motor driving the pump is adapted to turn over gently.
6. A braking system as claimed in any preceding claim, in which the signal generated by displacement of the pedal is fed to an electronic control unit which emits energising current to operate both the actuator 7 and the electric motor for driving the pump so that the actuator and the motor are operated in synchronism.
7. A braking system as claimed in any preceding claim, in which a solenoid-operated armature of the actuator is adapted to operate a cutoff valve comprising a valve head which is adapted to be urged against a seating surrounding an opening in a housing against a force in a return spring, the opening being connected to the high pressure source, and an exhaust port in the housing being connected to a return line to the reservoir.
8. A braking system as claimed in claim 7, in which the valve member comprises a ball for engagement with seating.
9. A braking system as claimed in claim 8, in which the seating is of part-spherical outline.
10. A braking system substantially as described herein with reference to and as illustrated in the accompanying drawings.
GB9520530A 1994-10-06 1995-10-04 Improvements in hydraulic braking systems of the brake-by-wire type Expired - Fee Related GB2293867B (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB9420192A GB9420192D0 (en) 1994-10-06 1994-10-06 Improvements in hydraulic braking systems of the brake-by-wire type

Publications (3)

Publication Number Publication Date
GB9520530D0 GB9520530D0 (en) 1995-12-13
GB2293867A true GB2293867A (en) 1996-04-10
GB2293867B GB2293867B (en) 1998-08-12

Family

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Family Applications (2)

Application Number Title Priority Date Filing Date
GB9420192A Pending GB9420192D0 (en) 1994-10-06 1994-10-06 Improvements in hydraulic braking systems of the brake-by-wire type
GB9520530A Expired - Fee Related GB2293867B (en) 1994-10-06 1995-10-04 Improvements in hydraulic braking systems of the brake-by-wire type

Family Applications Before (1)

Application Number Title Priority Date Filing Date
GB9420192A Pending GB9420192D0 (en) 1994-10-06 1994-10-06 Improvements in hydraulic braking systems of the brake-by-wire type

Country Status (2)

Country Link
DE (1) DE19537348A1 (en)
GB (2) GB9420192D0 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2321681A (en) * 1997-02-03 1998-08-05 Lucas Ind Plc Electronic braking system for vehicles

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19735018A1 (en) 1997-08-13 1999-02-18 Volkswagen Ag System architecture for realizing functions in a motor vehicle
DE19742920A1 (en) * 1997-09-29 1999-04-01 Itt Mfg Enterprises Inc Procedure for applying defined actuation forces

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1091084A (en) * 1963-12-04 1967-11-15 Butterley Co Ltd Improvements in and relating to hydraulic brake operating or clutch operating systems
GB2116271A (en) * 1982-03-05 1983-09-21 Messier Hispano Sa A circuit for controlling a braking system on a vehicle particularly an aircraft
EP0470858A1 (en) * 1990-08-10 1992-02-12 Honda Giken Kogyo Kabushiki Kaisha Hydraulic braking pressure control system for vehicle
GB2249598A (en) * 1988-01-07 1992-05-13 Honda Motor Co Ltd Apparatus for controlling hydraulic braking pressure for a vehicle

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1091084A (en) * 1963-12-04 1967-11-15 Butterley Co Ltd Improvements in and relating to hydraulic brake operating or clutch operating systems
GB2116271A (en) * 1982-03-05 1983-09-21 Messier Hispano Sa A circuit for controlling a braking system on a vehicle particularly an aircraft
GB2249598A (en) * 1988-01-07 1992-05-13 Honda Motor Co Ltd Apparatus for controlling hydraulic braking pressure for a vehicle
EP0470858A1 (en) * 1990-08-10 1992-02-12 Honda Giken Kogyo Kabushiki Kaisha Hydraulic braking pressure control system for vehicle

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2321681A (en) * 1997-02-03 1998-08-05 Lucas Ind Plc Electronic braking system for vehicles
GB2321681B (en) * 1997-02-03 2000-11-29 Lucas Industries Ltd Electronic braking system for vehicles

Also Published As

Publication number Publication date
GB9520530D0 (en) 1995-12-13
GB2293867B (en) 1998-08-12
DE19537348A1 (en) 1996-04-11
GB9420192D0 (en) 1994-11-23

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Legal Events

Date Code Title Description
732E Amendments to the register in respect of changes of name or changes affecting rights (sect. 32/1977)
732E Amendments to the register in respect of changes of name or changes affecting rights (sect. 32/1977)
PCNP Patent ceased through non-payment of renewal fee

Effective date: 20071004