WO1989005747A1 - Systemes d'antiblocage de frein pour vehicule - Google Patents

Systemes d'antiblocage de frein pour vehicule Download PDF

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Publication number
WO1989005747A1
WO1989005747A1 PCT/GB1988/001070 GB8801070W WO8905747A1 WO 1989005747 A1 WO1989005747 A1 WO 1989005747A1 GB 8801070 W GB8801070 W GB 8801070W WO 8905747 A1 WO8905747 A1 WO 8905747A1
Authority
WO
WIPO (PCT)
Prior art keywords
chamber
valve
piston
change
braking system
Prior art date
Application number
PCT/GB1988/001070
Other languages
English (en)
Inventor
Alastair John Young
Original Assignee
Automotive Products Plc
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 Automotive Products Plc filed Critical Automotive Products Plc
Publication of WO1989005747A1 publication Critical patent/WO1989005747A1/fr

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
    • B60T8/42—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 having expanding chambers for controlling pressure, i.e. closed systems
    • B60T8/4208—Debooster systems
    • B60T8/4225—Debooster systems having a fluid actuated expansion unit
    • B60T8/4233—Debooster systems having a fluid actuated expansion unit with brake pressure relief by introducing fluid pressure into the expansion unit
    • 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
    • B60T8/88—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 with failure responsive means, i.e. means for detecting and indicating faulty operation of the speed responsive control means
    • B60T8/92—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 with failure responsive means, i.e. means for detecting and indicating faulty operation of the speed responsive control means automatically taking corrective action
    • B60T8/94—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 with failure responsive means, i.e. means for detecting and indicating faulty operation of the speed responsive control means automatically taking corrective action on a fluid pressure regulator

Definitions

  • the present invention relates to vehicle antilock braking systems and in particular such systems in which reduction or reapplication of braking effort during an antilock cycle is effected by means of a power fluid source.
  • a vehicle antilock braking system comprises a master cylinder which will produce a source of fluid under pressure upon brake actuation, said master cylinder being connected to a brake circuit including a brake actuator associated with one of the wheels of the vehicle, said brake actuator being connected to the master cylinder via a displacement valve, said displacement valve including a piston, movement of said piston being controlled by means of a power fluid source via an antilock control valve, so that when the brake is applied fluid in the brake actuator may be displaced into the displacement valve to reduce the braking effort should deceleration of the wheel associated with that brake actuator rise above a level at which locking of the wheel is liable to occur, characterised in that a change-over valve is provided to apply master cylinder pressure to the piston to prevent displacement of the fluid from the brake actuator to the displacement valve should the ' power fluid source fail.
  • the brake pressure when the brake is applied the brake pressure will also be applied to the displacement valve and will act on one end of the piston thereof. It is consequently necessary to apply an opposing force to the piston in order to prevent movement thereof during normal braking.
  • This may be achieved by applying the power fluid to the piston so that it will apply a force thereto in the opposite direction to the brake pressure.
  • Means must however be provided to prevent movement of the piston or displacement of fluid from the brake actuator to the displacement valve in case of failure of the power fluid source. This is achieved by said change-over valve, which exposes the piston of the displacement valve to brake pressure in the opposite direction.
  • the antilock control valve will also control movement of the displacement valve to reapply pressure to the brake actuator and thus the braking effort, when the conditions under which a wheel is liable to lock cease to prevail.
  • Figure 1 is a diagrammatic illustration of a vehicle antilock braking system in accordance with the present invent ion ;
  • Figure 2 is a diagrammatic illustration of a modification to the system illustrated in figure 1;
  • Figure 3 is diagrammatic illustration of a further modification to the system illustrated in figure 1.
  • Figure 1 illustrates a dual circuit braking system controlled by a servo assisted master cylinder 11.
  • the master cylinder 11 is of conventional design, having a control plunger 12 which, upon movement of the brake pedal 13, v/ill cause a pair of pistons 14 and 15 to move within cylinder 16 and expel fluid under pressure from the cylinder 16 via a pair of outlets 17 and 18. Fluid is introduced into the chamber 16 from reservoir 19 via inlets cylinder 16 via a pair of outlets 17 and 18. Fluid is introduced into the chamber 16 from reservoir 19 via inlets 20 and 21.
  • the control plunger 12 is slidingly mounted within an axial bore of a servo piston 25 which acts against the end of piston 14.
  • a circumferential groove 26 in the external surface 33 of piston 25 provides a chamber which is connected to a pressure fluid accumulator 27.
  • a circumferential groove 28 is provided ⁇ plunger 12 and bores 29, 30 and 31 are provided in the servo piston 25 between the internal surface 32 and external surface 33, the internal surface 32 and end face 34, and the internal surface 32 and end face 35, respectively.
  • the end of cylinder 16 adjacent face 34 of piston 25 is closed to define a chamber 36.
  • a further chamber 37 is defined adjacent the end 35 of piston 25 this chamber 37 surrounding the piston 14 and being connected to the reservoir 19 via an outlet 38.
  • the groove 28 and bores 29, 30 and 31 are positioned such that when the brake is not applied, bore 29 will be closed by the plunger 12 while bores 30 and 31 will be interconnected by groove 28, so that the chamber 36 is connected via chamber 37 and outlet 38 to the reservoir 19.
  • communication between groove 28 and bore 31 is closed and bore 29 is interconnected with bore 30 so that pressurised fluid from accumulator 27 may be introduced into the chamber 36 and will act against the end of piston 25 to reinforce the force applied to pistons 14 and 15 by the plunger 12.
  • fluid from chamber 36 is permitted to drain back to the reservoir 19 via bore 30, groove 28, bore 31, chamber 27 and outlet 38.
  • the fluid pressure accumulator 27 is provided, with fluid under pressure by means of an electric pump 40 via non-return valve 41.
  • the electric pump 40 is controlled by pressure switch 43, to maintain the accumulator 27 at the required pressure.
  • a pressure release valve 42 is provided to ensure that the accumulator 27 is not over pressurised, should switch 43 fail to switch off the electric pump 40.
  • the outlets 17 and 18 from the master cylinder 11 are connected to separate braking circuits, each circuit being split to control two brake actuators 50 (only one shown), typically one brake actuator 50 in each circuit being associated with one of the front wheels of the vehicle and the other brake actuator 50 in each circuit being associated with the diagonally opposite rear wheel.
  • the two circuits of the system and the two splits of each circuit are identical in arrangement and operation and only one split of one circuit is described in detail below and illustrated in the drawings.
  • the outlet 17 of master cylinder 11 is connected via a displacement valve 51 to the brake actuator 50.
  • the displacement valve 51 comprises a piston 52 with enlarged diameter central portion 53 which is slidingly sealed within a correspondingly stepped closed cylinder 54, so as to define four fluid tight chambers 55, 56, 57 and 58.
  • Chamber 55 is connected via' an inlet 60 and ball valve 61 to outlet 17
  • a reduced diameter extension 53 of the end 54 of piston 52 extends through the inlet 60 to engage ball valve 61 and keep it open when the piston 52 is hard over to the left, as illustrated in figure 1.
  • a compression spring 65 acts between face 68 defined by the portion 53 of piston 52 and the opposite face of the stepped portion of cylinder 54, to bias the piston 52 towards the ball valve 61.
  • the chamber 56 of displacement valve 51 is selectively connected to the reservoir 19 via chamber 37 and outlet 38 or to the accumulator 27 via groove 26, by means of a proportional flow solenoid control valve 66, so that pressurised fluid may be applied to the face 67 of piston 52 to exert a force on the piston 52 to the right.
  • Chamber 57 of displacement valve 51 is connected to the accumulator 27 via groove 26, so that pressurised fluid may be applied to the face of 69 of piston 52 to exert a force opposing movement of the piston 52 towards the right.
  • Chamber 58 of the displacement valve 51 is selectively connected to inlet 17 or to the reservoir 19, via chamber 37 and outlet 38, by means of a change-over valve 70.
  • the change-over valve 70 has a stepped piston 71 which is slidably located within a correspondingly stepped cylinder 72, the piston 71 being sealed with respect to the cylinder 72 so as to define two fluid tight end chambers 73 and 74 and fluid tight intermediate chamber 75.
  • Chamber 73 of change-over valve 70 is connected via inlet 76 and ball valve 77 to outlet 17 of master cylinder 11.
  • a reduced diameter extension 79 of piston 71 extends through inlet 76 to engage and hold open the ball valve 77, when the piston 71 is hard over to the left.
  • Chamber 73 is connected to chamber 58 of displacement valve 51 and also to the corresponding chamber 58 of the displacement valve 51 controlling the other brake actuator 50 in the brake circuit connected to outlet 17.
  • Spring means 78 acts against the other end of piston 71 to urge the piston 71 towards the ball valve 77.
  • Chamber 75 of change-over valve 70 is connected to the accumulator 27 via groove 26, and chamber 74 is connected to reservoir 19 via chamber 37 and outlet 38.
  • the piston 71 has a longitudinal bore 80 which interconnects chambers 73 and 74.
  • a ball valve 81 is provided in the bore 80, the ball valve 81 closing towards chamber 74.
  • a plunger 82 extends from the end wall of cylinder 72 adjacent chamber 74, so that when the piston 71 moves to the right, the plunger 82 will engage and unseat ball valve 81.
  • the solenoid valve 66 is controlled in known manner to permit pressurised fluid to enter chamber 56 and cause piston 52 to move to the right. This movement will first close ball valve 61, isolating the brake actuator 50 from the master cylinder 11 and then as the volume of chamber 55 increases fluid wrJri flow into the chamber 55 from the brake actuator 50, thus reducing the 'braking effort. The rate at which the piston 52 moves and braking effort is thereby reduced is controlled by the rate at which fluid is allowed to flow into chamber 56 by solenoid valve 66. Reapplication of braking effort is achieved by connecting chamber 56 to reservoir 19 via solenoid valve 66, so that fluid under pressure may flow out of chamber 56 and the piston 51 will be moved back to the left by the pressure of fluid in chamber 57 and the spring 65.
  • each brake actuator 50 will have an independent displacement valve 51 and antilock control valve 66 to give independent antilock control on all four wheels. Only two change-over valves 70 are however required, one for each circuit of the system. Alternatively, the displacement valve 51 may be inserted in the brake circuit before the split so that one displacement valve 51 and antilock control valve 66 may control antilock operation of both brake actuators in each circuit.
  • change-over valve 70 is replaced by a solenoid valve 70' which may be arranged to switch connection of chamber 58 of displacement valve 51 from the reservoir 19 to outlet 17 of master cylinder 11, when pressure in the accumulator 27 has failed.
  • the solenoid valve 70' is controlled by pressure sensing means (not shown) associated with the accumulator 27.
  • the solenoid controlled main power valve 90 selectively connects chambers 75 of each of the change-over valve 70, to the reservoir 19 via chamber 37 and outlet 38 or to the accumulator 27 via groove 26.
  • the main power valve 90 will connect chamber 75 to reservoir 19, so that the piston 71 will be held over to the left by spring 78 and ball valve 77 will be open while ball valve 81 is closed.
  • Brake pressure will consequently be applied to chamber 58 whenever the brakes are applied, thus holding the piston 52 of displacement valve 51 to the left whether pressure is available from accumulator 27 or not. Consequently, any leakage past ball valve 81 will be detected under normal braking. Only upon antilock operation will the main power valve 90 be switched to connect the chamber 75 of the change-over valve 70 to the accumulator 27.
  • piston 71 to .move to the right, closing ball valve 77 and opening ball valve 81 to connect chamber 58 of displacement valve 51 to the reservoir, so that upon application of fluid under pressure to chamber 56 via solenoid valve 66 piston 52 will move to the right to reduce braking effort.
  • the accumulator 27 serves both the servo mechanism of the master cylinder and the antilock braking control valves, separate power sources may be used.
  • a master cylinder without servo assistance or with a vacuum servo assistance may be used.

Landscapes

  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Transportation (AREA)
  • Mechanical Engineering (AREA)
  • Regulating Braking Force (AREA)

Abstract

Un système d'antiblocage de frein pour véhicule comprend un maître-cylindre (11) produisant une source de fluide sous pression lors de l'actionnement du frein. Ledit maître-cylindre (11) est relié à un circuit de frein comprenant un actuateur de frein (50) associé à une des roues du véhicule, ledit actuateur de frein étant relié au maître-cylindre (11) par l'intermédiaire d'une valve de déplacement (51) comportant un piston (52). Le mouvement dudit piston (52) est commandé au moyen d'une source de fluide de puissance (27), par l'intermédiaire d'une valve de commande d'antiblocage (66), de sorte que pendant le freinage du véhicule, lors du déclenchement d'une opération d'antiblocage, le fluide se trouvant dans l'actuateur de frein (50) peut être déplacé jusque dans la valve de déplacement (51) afin de produire un effort de freinage. Une valve de commutation (70) applique la pression du maître-cylindre au piston (52) afin d'empêcher le déplacement de fluide à partir de l'actuateur de frein (50) jusqu'à la valve de déplacement (51), en cas de défaillance de la source de fluide de puissance (27).
PCT/GB1988/001070 1987-12-23 1988-12-05 Systemes d'antiblocage de frein pour vehicule WO1989005747A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB8729946A GB2213888A (en) 1987-12-23 1987-12-23 Vehicle antilock braking system
GB8729946 1987-12-23

Publications (1)

Publication Number Publication Date
WO1989005747A1 true WO1989005747A1 (fr) 1989-06-29

Family

ID=10628911

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/GB1988/001070 WO1989005747A1 (fr) 1987-12-23 1988-12-05 Systemes d'antiblocage de frein pour vehicule

Country Status (2)

Country Link
GB (1) GB2213888A (fr)
WO (1) WO1989005747A1 (fr)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4213621A1 (de) * 1992-04-24 1993-10-28 Teves Gmbh Alfred Blockiergeschützte hydraulische Bremsanlage
US5716111A (en) * 1996-04-22 1998-02-10 General Motors Corporation Rotary actuated braking system
US8162110B2 (en) 2008-06-19 2012-04-24 Thyssenkrupp Elevator Capital Corporation Rope tension equalizer and load monitor

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1512384A (en) * 1974-01-30 1978-06-01 Automotive Prod Co Ltd Fluid pressure braking systems
DE2924484A1 (de) * 1979-06-18 1981-02-12 Teves Gmbh Alfred Druckregelzylinder fuer bremsanlagen
FR2567826A1 (fr) * 1984-07-17 1986-01-24 Honda Motor Co Ltd Dispositif de commande de la pression hydraulique de freinage de vehicules

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3963276A (en) * 1973-08-24 1976-06-15 Kelsey-Hayes Company Skid control system embodying fail safe bypass
GB1567066A (en) * 1976-08-13 1980-05-08 Nissan Motor Anti skid control unit
DE2824482A1 (de) * 1978-06-03 1979-12-13 Bosch Gmbh Robert Hydraulische mehrkreisbremsanlage
US4457563A (en) * 1981-10-13 1984-07-03 Lucas Industries Public Limited Company Anti-skid hydraulic braking systems for vehicles
JPS59216756A (ja) * 1983-05-24 1984-12-06 Akebono Brake Ind Co Ltd 車両用アンチロツク装置
JPS6058460U (ja) * 1983-09-29 1985-04-23 アイシン精機株式会社 車両用アンチスキツド装置のアクチユエ−タ
GB8400991D0 (en) * 1984-01-14 1984-02-15 Lucas Ind Plc Anti-skid hydraulic braking systems

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1512384A (en) * 1974-01-30 1978-06-01 Automotive Prod Co Ltd Fluid pressure braking systems
DE2924484A1 (de) * 1979-06-18 1981-02-12 Teves Gmbh Alfred Druckregelzylinder fuer bremsanlagen
FR2567826A1 (fr) * 1984-07-17 1986-01-24 Honda Motor Co Ltd Dispositif de commande de la pression hydraulique de freinage de vehicules

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4213621A1 (de) * 1992-04-24 1993-10-28 Teves Gmbh Alfred Blockiergeschützte hydraulische Bremsanlage
US5716111A (en) * 1996-04-22 1998-02-10 General Motors Corporation Rotary actuated braking system
US8162110B2 (en) 2008-06-19 2012-04-24 Thyssenkrupp Elevator Capital Corporation Rope tension equalizer and load monitor

Also Published As

Publication number Publication date
GB8729946D0 (en) 1988-02-03
GB2213888A (en) 1989-08-23

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