EP0857129A1 - Procede pour faire fonctionner un servofrein pneumatique - Google Patents

Procede pour faire fonctionner un servofrein pneumatique

Info

Publication number
EP0857129A1
EP0857129A1 EP96938123A EP96938123A EP0857129A1 EP 0857129 A1 EP0857129 A1 EP 0857129A1 EP 96938123 A EP96938123 A EP 96938123A EP 96938123 A EP96938123 A EP 96938123A EP 0857129 A1 EP0857129 A1 EP 0857129A1
Authority
EP
European Patent Office
Prior art keywords
sealing seat
time interval
electromagnet
opening
actuation
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.)
Withdrawn
Application number
EP96938123A
Other languages
German (de)
English (en)
Inventor
Alfred Eckert
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.)
ITT Automotive Europe GmbH
Continental Teves AG and Co oHG
Original Assignee
ITT Automotive Europe GmbH
Alfred Teves GmbH
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 ITT Automotive Europe GmbH, Alfred Teves GmbH filed Critical ITT Automotive Europe GmbH
Publication of EP0857129A1 publication Critical patent/EP0857129A1/fr
Withdrawn legal-status Critical Current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
    • 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
    • B60T13/72—Electrical control in fluid-pressure brake systems in vacuum systems or vacuum booster units

Definitions

  • the invention relates to a method for operating a pneumatic brake booster for motor vehicles with an amplifier housing, the interior of which is divided by a movable wall into a first chamber (vacuum chamber) and a second chamber (working chamber), and with a control housing in which a on the movable wall acting pneumatic pressure difference controlling control valve is arranged, which has a first sealing seat, the opening of which allows ventilation of the working chamber, a second sealing seat, the opening of which enables a connection between the two chambers, and an elastic valve body which interacts with the two sealing seats
  • the first sealing seat can be actuated on the one hand by an actuating rod and on the other hand independently of the actuating rod by an electromagnet.
  • a pneumatic brake booster with electromagnetic auxiliary control is known from DE 44 05 092 Cl, in which the first sealing seat is formed on a cylindrical sleeve which is connected to the armature of an electromagnet arranged in the control housing.
  • a valve piston which is in force-transmitting connection with the actuating rod, is provided, on which the armature is supported axially and can thus be carried along by the valve piston during driver actuation.
  • the first sealing seat lifts off the valve body, so that the atmosphere can flow into the working chamber.
  • the control valve has a third sealing seat, which can be actuated by means of an electromagnet and which functionally replaces the second sealing seat when operated externally.
  • the control valve is actuated by the electromagnet against the direction of actuation by the driver, so that the valve body is moved away from the first sealing seat formed on the valve piston by moving the third sealing seat.
  • a first solution to the problem on which the invention is based is that the first sealing seat is moved at maximum speed in a first time interval in the actuating direction of the electromagnet until a maximum opening gap is created between the first sealing seat and the valve body, in a second Time interval the controlled position of the first sealing seat is kept constant, after which the first sealing seat is moved in a third time interval at maximum speed against the direction of actuation of the electromagnet in the sense of reducing the opening gap and the position of the first sealing seat controlled in the third time interval at the end of the braking initiated independently of the actuating rod is kept constant.
  • a second solution which is particularly suitable for pneumatic brake boosters, the control valves of which have an electromagnetically displaceable third sealing seat, which is actuated against the direction of actuation by the driver, consists in the fact that the third sealing seat coincides with the actuating direction of the electromagnet in a first time interval maximum speed is moved until an opening gap is formed between the first sealing seat and the valve body, the controlled position of the third sealing seat is kept constant in a second time interval, after which the third sealing seat in a third time interval at maximum speed against the actuation direction of the electromagnet in the Moving in order to reduce the opening gap and the position of the third sealing seat which was activated in the third time interval until the end of the braking independent of the actuating rod tant is kept.
  • the invention therefore consists in the use of position control of active, analog controllable brake boosters for the targeted representation of the on / off function. This ensures that the set position of the sealing seat is set to a pressure build-up position with a maximum gradient at the start of the function. After a certain time, which the brake system needs to build up the maximum pressure, a target position is specified which corresponds to a functional range lying between the pressure maintenance and the pressure build-up phase.
  • the manner in which the position control (sliding mode control) is described the required current value is very small (optimal), whereby no pressure build-up due to interference is possible.
  • FIG. 1 shows a first embodiment of an externally actuated brake force booster in longitudinal section; partially broken away, in the inactive standby position;
  • FIG. 2 shows a second embodiment of an externally actuated brake booster in the externally actuated position
  • FIG. 3 shows a diagrammatic representation of an external actuation of the brake booster shown in FIGS. 1 and 2, in particular the time profiles of the actuation path s h of the first and third sealing seats - FIG. 3a, of the pressure build-up in a master brake cylinder downstream of the brake boosters (FIG. 3b) and of the current supplied to the electromagnets of the brake booster (FIG. 3c).
  • the axially movable wall 2 consists of a sheet metal membrane plate 8 and an attached flexible membrane 18, which, not shown, forms a rolling membrane as a seal between the outer circumference of the membrane plate 8 and the booster housing 1.
  • the braking force is transmitted via a rubber-elastic reaction disk 6, which rests on the end face to a front part 17 of the control housing 5, and a pressure rod 14 having a head flange 23, to an actuating piston of a master brake cylinder (not shown) of the brake system, which is attached to the vacuum-side booster half.
  • an approximately radially extending channel 24 is finally formed in the control housing 5.
  • the first sealing seat 15 is formed at the end of a cylindrical sleeve 32 which is in force-transmitting connection with the armature 27 of an electromagnet 20, the coil 26 of which is arranged immovably in the control housing 5.
  • a valve piston 9 is provided which bears against the armature 31 under the pretension of a compression spring 13 which is supported on the sleeve 32.
  • the return movement of the valve piston 9 at the end of a braking operation is limited by a cross member 11, that in the release position of the vacuum brake booster shown in the drawing rests against a stop 19 formed in the booster housing 1.
  • the electromagnet 20 of the brake booster shown in FIG. 1 is acted upon by maximum current at the start of an external actuation (time T 0 ) and is thus actuated such that the first sealing seat 15 is in a first time interval T Q -TL at maximum speed away from the valve body 10 until there is an opening gap between it and the valve body 10 which, when the second sealing seat 16 is closed, causes the atmosphere to flow rapidly into the working chamber 3 and thus a sudden increase in the hydraulic pressure
  • a second time interval T x -T 2 subsequent to the first time interval To-Tl the current supplied to the electromagnet 20 is kept constant at the maximum level (T-max), so that the input in the first time interval T Q -T J
  • T-max the maximum level
  • the current supplied to the electromagnet 20 is reduced to a value I h , so that the first sealing seat 15 moves in the direction of the valve body 10 at maximum speed, ie in the sense of a reduction the distance between the sealing seat 15 and valve body 10 takes place.
  • the third time interval T2-T 3 is followed by a fourth time interval T 3 -T 4 , in which there is no movement of the first sealing seat 15 with respect to the valve body 10, so that the opening gap set in the third time interval T 2 -T 3 remains unchanged.
  • the hydraulic pressure controlled in the master brake cylinder remains constant during the third and fourth time interval until the actuating force applied by the driver is removed or the external braking process is terminated at time T 4 .
  • a fifth time interval T 4 -T 5 the current supplied to the electromagnet 20 is reduced to zero, so that the first sealing seat 15 moves under the action of the compression spring 13 towards the valve body 10 at maximum speed or into its rest position , which is determined by the mechanical stop of the armature 27 on the valve piston 9.
  • the hydraulic pressure in the master brake cylinder 2 is reduced to zero.
  • the control valve 12 of the brake booster shown in FIG. 2 consists of a first sealing seat 28 formed on the valve piston 9 connected to the actuating rod 7, a second sealing seat 29 formed in the control housing 5, and a third sealing seat 30 arranged radially between the two sealing seats 28, 29 and an annular valve body 31, which cooperates with the sealing seats 28, 29 and 30 and is guided in a guide part 32 arranged in a sealed manner in the control housing 5, which valve valve 33 supports the sealing seats 28, 29, 30 by means of a valve spring 33 which is supported on the guide part 32 is biased.
  • an electromagnet 34 is provided, which is preferably arranged in a housing 35 which is fixedly connected to the valve piston 9 and accordingly together with the valve piston 9 in the control housing 5 is displaceable.
  • Magnet 34 consists of a coil 36 arranged inside the housing 35 and an axially displaceable cylindrical armature 37 which is partially guided in a closure part 38 closing the housing 35 and on which a force transmission sleeve 39 is supported which supports the third sealing seat mentioned above 30 wears.
  • a compression spring 40 is arranged between the valve piston 9 and the force transmission sleeve 39, which holds the armature 37 in its starting position, in which the third sealing seat 30 is arranged axially offset with respect to the first sealing seat 28 formed on the valve piston 9.
  • the closing part 38 which is guided in the control housing 5, bears against the previously mentioned reaction disk 6 with the interposition of a transmission disk 41 and enables the input force introduced on the actuating rod 7 to be transmitted to the reaction disk 6.
  • the electromagnet 34 of the brake force booster shown in FIG. 2 is acted upon by maximum current at the start of external actuation (time T 0 ) and is thus actuated in such a way that the third sealing seat 30 in the first time interval T Q -TL is moved at maximum speed towards the valve body 31 until it comes to rest on it and bridges the function of the second sealing seat 29 mentioned above.
  • the third sealing seat 30 moves further, it is first pressed into the material of the valve body 31 in the direction of actuation of the electromagnet 34, ie against the direction of actuation of the brake booster, and then displaces it away from the first sealing seat 28, so that between the valve body 31 and the
  • the current supplied to the electromagnet 34 is kept constant at the maximum level (Imax), so that the position of the third sealing seat 30 controlled in the first time interval T Q -T X and thus the size of the opening gap or the distance of the first sealing seat 28 from the valve body 31 cannot be changed and the pressure in the master brake cylinder is kept at a constant level.
  • a third time interval T 2 -T 3 the current supplied to the electromagnet 34 is reduced to a value I h , so that a movement of the third sealing seat 30 at maximum speed against the direction of actuation of the electromagnet 34, ie in the sense of a reduction of the opening gap between the valve body 31 and the first sealing seat 28 takes place.
  • the third time interval T 2 -T 3 is followed by a fourth time interval T 3 -T4, in which there is no movement of the third sealing seat 31 with respect to the first sealing seat 28, so that the
  • a fifth time interval T 4 -T 5 the current supplied to the electromagnet 34 is reduced to zero so that the third sealing seat 30 moves under the action of the compression spring 40 into its rest position at maximum speed, which is achieved by the mechanical stop of the Anchor 37 is determined on the closure part 38.
  • the pneumatic pressure compensation between the two chambers 3, 4 or the return movement of the movable wall 2 is initiated by opening the second sealing seat 29, the hydraulic pressure in the master brake cylinder 2 is reduced to zero.
  • the times T Q to T 5 delimiting the individual time intervals can be determined as a function of threshold values of a displacement sensor (not shown) that detects the movement of the movable wall 2 or a pressure sensor (also not shown) with which the hydraulic pressure prevailing in or behind the master brake cylinder is sensed.

Abstract

L'invention concerne un procédé pour faire fonctionner un servofrein pneumatique à commande électromécanique. Pendant une première période (T0-T1), un siège d'étanchéité (15) d'une soupape de commmande (12), actionné par un électroaimant (20), est déplacé dans le sens d'actionnement de l'électroaimant (20) à une vitesse maximale jusqu'à obtention d'un intervalle d'ouverture maximal entre le siège d'étanchéité (15) et le corps (10) de la soupape de commande (12), ce qui engendre un rapide afflux d'atmosphère dans la chambre de travail (3) du servofrein. Dans une seconde période (T1-T2), la position du siège d'étanchéité (15) ainsi obtenue est maintenue constante. Et enfin pendant une troisième période (T2-T3), le siège d'étanchéité (15) est déplacé à une vitesse maximale dans le sens inverse du sens d'actionnement de l'électroaimant (20) afin de réduire l'intervalle d'ouverture et la position du premier siège d'étanchéité (15) ainsi obtenue est maintenue constante jusqu'à achèvement de l'opération de freinage indépendamment de la barre d'actionnement (7).
EP96938123A 1995-11-08 1996-11-07 Procede pour faire fonctionner un servofrein pneumatique Withdrawn EP0857129A1 (fr)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
DE19541535 1995-11-08
DE1995141535 DE19541535A1 (de) 1995-11-08 1995-11-08 Verfahren zum Betrieb eines pneumatischen Bremskraftverstärkers
PCT/EP1996/004859 WO1997017240A1 (fr) 1995-11-08 1996-11-07 Procede pour faire fonctionner un servofrein pneumatique

Publications (1)

Publication Number Publication Date
EP0857129A1 true EP0857129A1 (fr) 1998-08-12

Family

ID=7776870

Family Applications (1)

Application Number Title Priority Date Filing Date
EP96938123A Withdrawn EP0857129A1 (fr) 1995-11-08 1996-11-07 Procede pour faire fonctionner un servofrein pneumatique

Country Status (5)

Country Link
EP (1) EP0857129A1 (fr)
JP (1) JPH11514607A (fr)
AU (1) AU7566796A (fr)
DE (1) DE19541535A1 (fr)
WO (1) WO1997017240A1 (fr)

Families Citing this family (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19735035A1 (de) * 1997-08-13 1999-02-18 Itt Mfg Enterprises Inc Unterdruckbremskraftverstärker für Kraftfahrzeuge
DE19748657A1 (de) * 1997-11-04 1999-05-12 Lucas Ind Plc Pneumatischer Bremskraftverstärker mit mechanischer und elektromagnetischer Betätigung
US6318815B1 (en) * 1998-01-31 2001-11-20 Continental Teves Ag & Co., Ohg Braking force boosting device, in particular for automotive vehicles
JP2000079877A (ja) * 1998-06-29 2000-03-21 Aisin Seiki Co Ltd 負圧式倍力装置
DE10151465B4 (de) * 2000-10-19 2008-01-31 Aisin Seiki K.K., Kariya Fahrzeugbewegungssteuervorrichtung
JP2002137726A (ja) * 2000-10-31 2002-05-14 Tokico Ltd ブレーキ倍力装置
US8128179B2 (en) 2002-05-23 2012-03-06 Continental Teves Ag & Co. Ohg Method for operating an actuating unit for motor vehicle brakes
DE10302085A1 (de) * 2002-05-23 2003-12-11 Continental Teves Ag & Co Ohg Verfahren zum Betrieb einer Betätigungseinheit für Kraftfahrzeugbremsen

Family Cites Families (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3705333A1 (de) * 1986-02-20 1987-08-27 Tokico Ltd Bremsvorrichtung fuer kraftfahrzeuge
DE3920766C3 (de) * 1989-06-24 2002-09-19 Continental Teves Ag & Co Ohg Unterdruckbremskraftverstärker für eine schlupfgeregelte Bremsanlage
DE4028290C1 (fr) * 1990-09-06 1992-01-02 Daimler-Benz Aktiengesellschaft, 7000 Stuttgart, De
DE4238333C2 (de) * 1992-11-13 2001-10-11 Continental Teves Ag & Co Ohg Unterdruckbremskraftverstärker
DE4324688A1 (de) * 1993-07-23 1995-01-26 Teves Gmbh Alfred Unterdruckbremskraftverstärker
DE4309850C2 (de) * 1993-03-26 1996-12-12 Lucas Ind Plc Bremskraftverstärkersystem zum Regeln eines Bremsdruckes mit einem Bremskraftverstärker
DE4324205A1 (de) * 1993-07-19 1995-01-26 Teves Gmbh Alfred Bremsanlage für Kraftfahrzeuge
DE4405092C1 (de) * 1994-02-17 1994-12-22 Lucas Ind Plc Pneumatischer Kraftverstärker mit elektromagnetischer Hilfssteuerung, insbesondere für Kraftfahrzeug-Bremsanlagen
DE4410699C2 (de) * 1994-03-28 2001-10-04 Continental Teves Ag & Co Ohg Hydraulische Bremsanlage für Kraftfahrzeuge

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO9717240A1 *

Also Published As

Publication number Publication date
JPH11514607A (ja) 1999-12-14
DE19541535A1 (de) 1997-05-15
WO1997017240A1 (fr) 1997-05-15
AU7566796A (en) 1997-05-29

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