EP1202890A1 - Servofrein a depression avec assistance mecanique au freinage d'urgence et amortissement ameliore des bruits - Google Patents

Servofrein a depression avec assistance mecanique au freinage d'urgence et amortissement ameliore des bruits

Info

Publication number
EP1202890A1
EP1202890A1 EP00951491A EP00951491A EP1202890A1 EP 1202890 A1 EP1202890 A1 EP 1202890A1 EP 00951491 A EP00951491 A EP 00951491A EP 00951491 A EP00951491 A EP 00951491A EP 1202890 A1 EP1202890 A1 EP 1202890A1
Authority
EP
European Patent Office
Prior art keywords
armature
input member
permanent magnet
brake booster
vacuum brake
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Withdrawn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
EP00951491A
Other languages
German (de)
English (en)
Inventor
Peter Schlüter
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 EP1202890A1 publication Critical patent/EP1202890A1/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Withdrawn legal-status Critical Current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
    • 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
    • B60T8/321—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 deceleration
    • B60T8/3255—Systems in which the braking action is dependent on brake pedal data
    • B60T8/3275—Systems with a braking assistant function, i.e. automatic full braking initiation in dependence of brake pedal velocity
    • 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
    • B60T13/24—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 the fluid being gaseous
    • B60T13/46—Vacuum systems
    • B60T13/52—Vacuum systems indirect, i.e. vacuum booster units
    • B60T13/57—Vacuum systems indirect, i.e. vacuum booster units characterised by constructional features of control 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
    • B60T17/00—Component parts, details, or accessories of power brake systems not covered by groups B60T8/00, B60T13/00 or B60T15/00, or presenting other characteristic features
    • B60T17/002—Air treatment devices
    • B60T17/008—Silencer devices
    • 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
    • B60T7/00—Brake-action initiating means
    • B60T7/12—Brake-action initiating means for automatic initiation; for initiation not subject to will of driver or passenger

Definitions

  • the invention relates to vacuum brake booster of the type mentioned in the preamble of claim 1.
  • Such a vacuum brake booster is known from the unpublished DE 298 19 224 UI.
  • Vacuum brake boosters as such have been known for a long time and are in use millions of times to support the actuation forces of a hydraulic vehicle brake system and thereby to keep them at a pleasantly low level for the driver of a vehicle.
  • Vacuum brake boosters have recently been increasingly equipped with a so-called brake assistant.
  • This term is usually understood to mean a system which can provide a driver with increased braking power in the event of emergency braking with essentially the same actuation force.
  • Systems of this type have been developed because studies have shown that the majority of vehicle users do not step on the brake pedal as hard as is necessary to achieve maximum braking power during emergency braking. The vehicle's stopping distance is therefore longer than necessary.
  • Systems of this type that are already in production use an electromagnetically actuated brake booster in conjunction with a device that can determine the actuation speed of the brake pedal.
  • this device determines an actuation speed that is above a predetermined threshold value, it is assumed that there is an emergency braking situation and the brake booster is fully controlled by means of the electromagnetic actuation device, ie it provides its highest possible amplification power.
  • Brake boosters with electromagnetic actuation options are too expensive for motor vehicles in the lower and medium price range, which is why solutions have been developed that provide a brake assistant function without an electromagnetically actuated control valve (see DE 298 19 224 UI mentioned above).
  • the brake assist function is implemented in these solutions by pulling an armature, which is rigidly coupled to a valve seat, which controls the supply of atmospheric pressure into the brake booster (atmospheric sealing seat), after a defined switch-on threshold has been reached, and is pulled into contact with a permanent magnet then keeps said valve seat open until the driver releases the armature from the permanent magnet again by a fixed return stroke of the brake pedal.
  • the invention has for its object to provide a vacuum brake booster of the type mentioned, ie with a brake assy that can be switched on and off without electromagnetic help. stent function to provide, in which these unwanted impact noises no longer appear or at least no longer disturbing.
  • a permanent magnet and an armature interacting with it are arranged in the housing of the control valve.
  • the armature is on the one hand rigidly coupled to the input member of the brake booster or the control valve and on the other hand to the first valve seat (atmospheric sealing seat).
  • the armature which can be moved back and forth relative to the permanent magnet, is resiliently biased in the opposite direction of actuation and held in the starting position of the control valve at a first distance from the permanent magnet, preferably by the resilient bias against the direction of actuation.
  • the armature can be less than a predetermined second distance from the permanent magnet, which is smaller than the first distance.
  • Valve seat fully open (brake assistant function), so that the brake booster builds up the highest possible pressure difference between its vacuum chamber and its working chamber, ie the brake booster provides its maximum boosting power.
  • the return stroke movement of the input member or components of the control valve that are operatively connected to the input member after the armature has been released is cushioned before the input member has completed its maximum return stroke relative to the control valve housing. This cushioning or damping of the return stroke movement is achieved in the present invention with the same spring that biases the armature against the direction of actuation.
  • this armature return spring is coupled to the input member such that the latter only runs onto the spring after the armature has been released from the permanent magnet, ie after the brake assistant function has been switched off, and specifically before the input member has completed its return stroke.
  • the spring is supported on a housing-fixed component and prevents the return movement of the
  • the energy introduced into the input member after the brake assist function has been switched off is at least partially absorbed by the aforementioned spring, so that a metallic hard stop of the input member or components connected to it on the return stroke-limiting parts of the control valve housing is avoided.
  • a transmission piston rigidly coupled to the input member is provided in the region of its end facing away from the input member with an annular groove which has a defined axial extent.
  • annular groove In this annular groove, an annular disc is axially displaceably guided, on which the end of the armature return spring facing away from the armature is supported.
  • the annular groove is positioned and its axial extent is dimensioned such that the annular disc can only come into contact with the edge of the annular groove remote from the input member after the armature has been released from the permanent magnet, ie only after the brake assistant function has been switched off.
  • the last-mentioned embodiment is preferably developed in such a way that the annular disk is pressed against a cover of the control valve housing by the armature return spring when it is not in contact with the edge of the annular groove which is distant from the input member - that is to say in the vast majority of all operating states.
  • the cover represents the above-mentioned housing-fixed component on which the spring is supported.
  • the ring disk on the side that comes into contact with the edge of the ring groove after the brake assist function has been switched off is preferably provided with a shock-absorbing elastomer layer. With this elastomer layer, the washer is supported on the housing-fixed component in the other operating states.
  • said second distance is determined by the size of the resilient bias acting on the armature. If the resilient bias acting on the armature is small, this means that the second distance mentioned is relatively large, i.e. the threshold that must be exceeded to trigger the brake assist function is relatively low. The reverse is true if the resilient bias acting on the armature is large.
  • the first valve seat of the control valve which controls the ventilation of the working chamber, is in
  • first valve seat can also be actuated directly by the input member.
  • the first valve seat is preferably formed on an extension, in particular sleeve-shaped, rigidly connected to the armature. In this way, every movement of the armature is transmitted to the first valve seat without play.
  • a bolt rigidly coupled to the input member preferably extends into a recess in the extension in which the bolt has a play in the direction of displacement of the input member that is less than the maximum possible Actuation stroke of the input member is.
  • the bolt rigidly coupled to the input member can be used during the return movement of the input member, i.e. when releasing the brake, if necessary, detach the extension rigidly connected to the armature from the permanent magnet, i.e. switch off the brake assist function.
  • the exact shape of the recess in the extension is unimportant, the only thing that is decisive is that the bolt or another part rigidly connected to the input member comes into positive engagement with the extension during the return movement.
  • the input member is preferably resiliently biased against the actuation direction.
  • this resilient bias returns the input member to the starting position.
  • this resilient bias of the input member during its return movement to the starting position is also used to detach the armature from the permanent magnet, for example by means of the aforementioned latch, which engages in a recess in the extension coupled to the armature.
  • this return stroke movement is preferably damped by an elastomer element which is located between the armature and the stop surface is arranged, towards which the armature moves during its return stroke movement.
  • the elastomer element is an O-ring.
  • the permanent magnet is guided displaceably in the control valve housing and is preferably also resiliently biased against a stop against the direction of actuation.
  • Such an embodiment has the advantage that when the armature has fallen below the predetermined second distance to the permanent magnet as part of a rapid actuation of the brake booster and has consequently been pulled into contact with the permanent magnet, and that exerted on the input member Actuating force is further increased, this actuating force is not transmitted from the input member via the armature and permanent magnet unit to the control valve housing and from there to a master cylinder connected downstream of the vacuum brake booster, but rather that an increased actuating force exerted on the input member is transmitted directly from the input member to the downstream master cylinder becomes.
  • the magnet device in particular the armature, the permanent magnet and the latter receiving components, can therefore be made less stable. If, for all conceivable actuation cases, it is to be avoided that the magnet device gets into a force-transmitting state, then the permanent magnet must be displaceable in the actuation direction relative to the control valve housing by a distance which is greater than the maximum possible actuation stroke of the input member minus the mentioned first distance. In order to prevent the presence of a stop for the permanent magnet due to manufacturing tolerances, the contact surface of the permanent magnet being skewed with respect to the contact surface of the armature, which can possibly lead to tilting and, as a result, possibly jamming of the armature and / or the permanent magnet.
  • the stop for the permanent magnet and / or the contact surface formed on the permanent magnet (or its holder) and interacting with the abovementioned stop is convex. Furthermore, there is radial play between the permanent magnet or its holder and the control valve housing. In this way, the permanent magnet can always align correctly with the armature. Alternatively, the armature itself can be designed so that its contact surface is allowed a certain pivot to compensate for the misalignment mentioned.
  • the permanent magnet can be resiliently pretensioned against the stop in any way, it is preferred to use an overall annular spring element having a plurality of resilient circular ring segments for pretensioning the permanent magnet against the direction of actuation.
  • an overall annular spring element having a plurality of resilient circular ring segments for pretensioning the permanent magnet against the direction of actuation.
  • Such a spring element has a very small axial length and therefore reduces the overall length of the control valve equipped with a magnetic device according to the invention.
  • the armature consists of a base and an associated magnetic plate facing the permanent magnet.
  • the magnetic plate need be made of a material that is attracted to the permanent magnet, while the base of the armature can be made of non-magnetic material, for example of a plastic. If the armature is hollow cylindrical, then the magnetic plate is preferably ring-shaped.
  • Fig. 1 shows a longitudinal section through the one of interest here
  • FIG. 2 the view according to FIG. 1 in an actuation position in which the so-called brake assistant function is switched on, and
  • Fig. 3 shows the view of FIG. 1 immediately after switching off the brake assist function.
  • a brake booster 10 is shown with a housing 14 formed from sheet metal shells 12, the interior of which is divided by a movable wall 16 into a vacuum chamber 18 and a working chamber 20.
  • the vacuum chamber 18 is in constant operation with the brake booster 10 in connection with a vacuum source, for example with the intake tract of an internal combustion engine or with a vacuum pump.
  • a control valve 22 with a housing 24 is provided to selectively either establish a connection between the working chamber 20 and the vacuum chamber 18 so that the working chamber 20 can be evacuated, or a connection between the evacuated working chamber 20 and the ambient atmosphere, i.e. to produce the ambient pressure.
  • the movable wall 16 is coupled to the control valve housing 24 in a force-transmitting manner.
  • the brake booster 10 is actuated by means of a rod-shaped input member 26 which is resiliently biased into its initial position and which projects into the control valve housing 24 along an axis A and is fastened with its one spherical end 28 in a transmission piston 30. > ) > _. oo ⁇ o ft
  • DJ oi 3 "g ⁇ -s • -1 3 co t ⁇ ⁇ ⁇ v ⁇ H 1 3 3 • tl P- t tn P- tr t ⁇ in o DJ 3 3 d DJ 3 ⁇ - ⁇ 1 3 UI H- CL P 1 t rt o P- O - ⁇ P 1 DJ ⁇ 1 3 1 ⁇ 3 1 ⁇ CL ⁇ tn DJ: 3 P "1 1) DJ rt 1 3 ⁇ 1 1 1 o 1 tl 1
  • DJ 3 ⁇ 00 3 ⁇ ⁇ cn ⁇ v ⁇ d 3 tr cn J> v ⁇ ⁇ > p- 3 H) DJ - ⁇ ⁇ 00 ⁇ - ⁇ i ⁇ ⁇ cn ⁇ ⁇ lh ⁇ tn tl DJ CL ⁇ cn CL: « ⁇ o ⁇ N ⁇ ⁇ ⁇ 3 DJ 3 * ⁇ d: CL tr CL rt tl H rt CL 3 CL C / jn rt iQ ⁇ ⁇ P * 3 d ⁇ cn cn 3 rt W 3 ⁇ tr ⁇ 1 * 1 ⁇ ⁇ ⁇
  • the bolt 32 protrudes through a recess 70 of the sleeve-shaped extension 62.
  • the bolt 32 has a play in the direction of the axis A that is smaller than the maximum possible stroke of the bolt 32 in the channel 34.
  • the displacement of the armature 38 has the effect that the first valve seat 64 formed on the hollow cylindrical extension 62 is lifted off the valve sealing member 66, as a result of which ambient air passes through a channel 72 surrounding the inlet member 26 and past the open valve seat 64 through the channel formed in the control valve housing 24 34 can get into the working chamber 20.
  • a pressure difference then arises on the movable wall 16 and the resulting force is transmitted from the movable wall 16 to the control valve housing 24, which outputs this force by means of a force output tappet 74 to a master cylinder (not shown here).
  • the first valve seat 64 of the control valve 22 is thus opened more or less depending on the displacement of the input member 26 relative to the control valve housing 24, which results in a correspondingly increasing support force of the brake booster 10, which results from the pressure difference acting on the movable wall 16.
  • normal service braking which is referred to here as normal braking
  • the input member 26 and thus also the armature 38 are displaced relatively little in the actuation direction.
  • the spring 42 is designed so that the armature 38 from it ⁇ _o to to
  • the axial extent s of the annular groove 46 is selected such that the right edge of the annular groove 46 does not limit the actuation stroke of the transmission piston 30 during normal braking.

Landscapes

  • Engineering & Computer Science (AREA)
  • Transportation (AREA)
  • Mechanical Engineering (AREA)
  • Braking Systems And Boosters (AREA)

Abstract

Selon l'invention, un induit (38) placé sur le corps de soupape de commande d'un servofrein à dépression (24) coopère avec un aimant permanent (40) et est accouplé de manière rigide d'une part avec l'organe d'entrée (26) dans le sens d'actionnement et d'autre part avec le premier siège de soupape (64). Un ressort (42) sollicite l'induit (38) à l'encontre du sens d'actionnement et le maintient dans la position initiale de la soupape de commande (22), à une première distance de l'aimant permanent (40). Lorsque l'induit (38) s'approche de l'aimant permanent (40), il est attiré par ce dernier et vient en contact avec lui, s'il se trouve à une distance inférieure à une deuxième distance prédéterminée, elle-même inférieure à la première, à l'encontre de la force exercée par le ressort (42) sur l'induit (38), l'accouplement rigide de l'induit et de l'organe d'entrée (26) dans le sens d'actionnement étant alors supprimé. Afin d'amortir les bruits indésirables produits lorsque l'induit vient en contact avec l'aimant permanent, le ressort (42) sollicitant l'induit (38) à l'encontre du sens d'actionnement est accouplé mécaniquement avec l'organe d'entrée de façon à amortir le mouvement de rappel effectué par l'organe d'entrée (26) lorsque l'induit (38) se sépare de l'aimant permanent (40), avant que l'organe d'entrée (26) n'ait effectué sa course de rappel maximale par rapport au corps de soupape de commande (24).
EP00951491A 1999-08-12 2000-08-09 Servofrein a depression avec assistance mecanique au freinage d'urgence et amortissement ameliore des bruits Withdrawn EP1202890A1 (fr)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
DE19938040A DE19938040C1 (de) 1999-08-12 1999-08-12 Unterdruckbremskraftverstärker mit mechanischer Notbremshilfe und verbesserter Geräuschdämpfung
DE19938040 1999-08-12
PCT/EP2000/007747 WO2001012484A1 (fr) 1999-08-12 2000-08-09 Servofrein a depression avec assistance mecanique au freinage d'urgence et amortissement ameliore des bruits

Publications (1)

Publication Number Publication Date
EP1202890A1 true EP1202890A1 (fr) 2002-05-08

Family

ID=7918043

Family Applications (1)

Application Number Title Priority Date Filing Date
EP00951491A Withdrawn EP1202890A1 (fr) 1999-08-12 2000-08-09 Servofrein a depression avec assistance mecanique au freinage d'urgence et amortissement ameliore des bruits

Country Status (4)

Country Link
US (1) US6520063B2 (fr)
EP (1) EP1202890A1 (fr)
DE (1) DE19938040C1 (fr)
WO (1) WO2001012484A1 (fr)

Families Citing this family (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE10054252B4 (de) 2000-11-02 2006-05-18 Lucas Varity Gmbh Unterdruck-Bremskraftverstärker mit mechanischer Notbremshilfe
US7137082B1 (en) * 2003-03-28 2006-11-14 Magma Design Automation Inc. Reduced architecture processing paths
EP1711385B1 (fr) * 2004-02-02 2009-12-09 Lucas Automotive GmbH Generateur de force de freinage pour un systeme de freinage hydraulique de vehicule
US7481414B2 (en) * 2006-05-05 2009-01-27 Siemens Canada Limited Natural vacuum leak detection device with magnetic damping
FR2938224B1 (fr) * 2008-11-10 2011-10-14 Bosch Gmbh Robert Servomoteur pneumatique d'assistance de freinage d'un vehicule sans a coup pedale.
DE102014220441A1 (de) * 2014-01-16 2015-07-16 Continental Teves Ag & Co. Ohg Bremsanlage für Fahrzeuge
JP2017165181A (ja) 2016-03-15 2017-09-21 ローベルト ボッシュ ゲゼルシャフト ミット ベシュレンクテル ハフツング ブレーキ力の倍力装置
CN112874496A (zh) * 2021-02-26 2021-06-01 高小明 一种汽车制动用真空助力器

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4211849A1 (de) * 1992-04-08 1993-10-14 Lucas Ind Plc Pneumatischer Bremskraftverstärker mit elektromagnetischer Hilfssteuerung, insbesondere für Kraftfahrzeuge
DE19529387A1 (de) * 1995-08-10 1997-02-13 Teves Gmbh Alfred Verfahren zum Betrieb eines pneumatischen Bremskraftverstärkers
JP3456506B2 (ja) * 1995-12-22 2003-10-14 株式会社ボッシュオートモーティブシステム 倍力装置
DE19802846A1 (de) * 1998-01-26 1999-08-05 Lucas Ind Plc Manuell und automatisch betätigbare Bremskraftverstärker/Hauptzylinder-Einheit mit definierter Ruhelage des manuellen Betätigungsgliedes
EP1100705B1 (fr) 1998-08-05 2003-09-03 Lucas Industries Public Limited Company Servofrein a depression avec assistance mecanique au freinage d'urgence
DE19850478C2 (de) 1998-11-02 2003-05-15 Lucas Ind Plc Unterdruckbremskraftverstärker mit magnetloser Notbremshilfe

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO0112484A1 *

Also Published As

Publication number Publication date
WO2001012484A1 (fr) 2001-02-22
DE19938040C1 (de) 2001-01-04
US20020121187A1 (en) 2002-09-05
US6520063B2 (en) 2003-02-18

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