WO2021254569A1 - Servofrein ayant une liaison pneumatique définie - Google Patents

Servofrein ayant une liaison pneumatique définie Download PDF

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Publication number
WO2021254569A1
WO2021254569A1 PCT/DE2021/200077 DE2021200077W WO2021254569A1 WO 2021254569 A1 WO2021254569 A1 WO 2021254569A1 DE 2021200077 W DE2021200077 W DE 2021200077W WO 2021254569 A1 WO2021254569 A1 WO 2021254569A1
Authority
WO
WIPO (PCT)
Prior art keywords
brake booster
pneumatic brake
insert part
booster
control housing
Prior art date
Application number
PCT/DE2021/200077
Other languages
German (de)
English (en)
Inventor
Jürgen Faller
Ralf Jakobi
Original Assignee
Continental Teves Ag & Co. Ohg
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 Continental Teves Ag & Co. Ohg filed Critical Continental Teves Ag & Co. Ohg
Publication of WO2021254569A1 publication Critical patent/WO2021254569A1/fr

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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
    • B60T13/24—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
    • B60T13/573—Vacuum systems indirect, i.e. vacuum booster units characterised by reaction devices

Definitions

  • the invention relates to a pneumatic brake booster for motor vehicles.
  • Pneumatic brake boosters for brake systems in vehicles are known and widely used. For installation in a vehicle, these are usually provided as a subassembly or component of a braking device which, in addition to the brake booster, also includes a main brake cylinder coupled to it with a pressure medium tank and, if necessary, further add-on components.
  • Brake boosters cause operating noises during operation.
  • the main reasons for this are mechanical contacts between moving components and air currents and the associated turbulence.
  • a significant proportion of the noise generated by a pneumatic brake booster occurs during and after what is known as a reverse run after the end of a braking process.
  • a compressed return spring drives the axially movable components of the brake booster back to their non-actuated starting position as far as they will go.
  • a known solution for reducing such return noises is to reduce the return speed of the moving mechanical components. This reduces both the turbulence due to the air currents and the intensity of the attack.
  • the return speed is always a compromise between a fast response time with a rather low inertia and a particularly low-noise behavior of the brake booster with a rather higher inertia.
  • the return speed cannot be set as small as desired, and it is also not possible to define a single defined return speed for all applications.
  • the return speeds aimed at for the respective application can vary greatly. There is therefore a constant desire to be able to set the return speed as precisely and reproducibly as possible to a desired value.
  • the task is therefore to offer a pneumatic brake booster in which the return speed can be set in a particularly precise, cost-effective and reliably reproducible manner.
  • FIG. 1 shows a greatly simplified schematic diagram of a generic brake booster in three different operating states.
  • FIG. 2 shows a control housing of a known embodiment in axial section.
  • FIG. 3 spatial exploded view of an insert part with a known control housing according to FIG.
  • Fig. 4 Flow course in a known control housing according to Fig. 2.
  • FIG. 5 a spatial partial view of an embodiment of a control housing according to the invention and an enlarged detailed view in the area of the constriction.
  • FIG. 6 Flow course in a control housing according to Fig. 5.
  • 7 shows an enlarged view of a first embodiment of the constriction in axial section.
  • FIG. 8 shows an enlarged view of a second embodiment of the constriction in axial section.
  • FIG. 1 shows, in a greatly simplified manner, the functional principle of a pneumatic brake booster 1 in an unactuated starting position (a), in a forward run during a braking process (b) and a return after a braking process (c).
  • a generic brake booster 1 has a thin-walled booster housing 2. an axially movable partition 16, sealed off from booster housing 2, separates a vacuum chamber 3 from a working chamber 4 therein.
  • a valve arrangement 5 controls pneumatic connections between vacuum chamber 3 and working chamber 4 between working chamber 4 and the surrounding atmosphere. Both the valve arrangements 5 and the corresponding channels for the aforementioned pneumatic connections are arranged in a named control housing 12, which is firmly connected to the partition 16 and is mounted so as to be displaceable along the central axis A relative to the booster housing 2. a) In a non-actuated starting position, the air is evacuated from both the negative pressure chamber 3 and the working chamber 4, so that the same negative pressure is present therein.
  • valve arrangement 5 can be actuated either directly by the driver via an actuating member 17 in actuating direction B or indirectly and even completely independently of the driver via an electromagnetic switching device not shown here, for example.
  • the valve arrangements 5 release a pneumatic connection between the ambient atmosphere and the working chamber 4 and at the same time block the pneumatic connection between the negative pressure chamber 3 and working chamber 4.
  • An air stream 19 flows into the working chamber 4, as a result of which there is a differential pressure on the intermediate wall 16 arises.
  • the differential pressure drives the partition 16 together with the control housing 12 in the direction of the vacuum chamber 3.
  • a push rod 18 coupled to the control housing 12 transmits the increased force to a downstream master cylinder, not shown here.
  • control housing 12 in axial section.
  • the control housing 12 is designed, in particular on its outer contour, to be essentially rotationally symmetrical about the central axis A in order to simplify the seal with respect to the amplifier housing 2 and the partition 16.
  • the control housing 12 which has a complex internal shape, is made of plastic, preferably in an injection molding process, and is therefore only wear-resistant to a limited extent.
  • a separate insert 6 made of sheet steel in the example shown is used - a so-called guide plate.
  • the insert part 6 is inserted in the control housing 11 in a corresponding receiving seat, where it is supported radially and axially against the actuation direction.
  • An air channel 20 leads through the control housing 12 from the valve arrangement 5 to the insert part 6.
  • the insert part 6 has several openings 7 for the air flow to pass between the working chamber 4 and the vacuum chamber 3.
  • FIG. 3 shows the known control housing 12 according to FIG. 2 and the insert part 6 in a three-dimensional exploded view.
  • the radial and axial support of the insert 6 in the control housing 12 is provided by a plurality of support ribs 14 which are profiled complementarily to the outer profile of the insert 6 and which are molded onto the control housing 12 and distributed over the circumference thereof.
  • the insert part 6 has a total of 8 circular openings 7, which are arranged evenly distributed over the circumference
  • FIG. 4 shows the air flow through the known control housing 12 in a return line according to FIG. 1c.
  • a bypass 21 is formed in the area of the curves and diameter transitions between the control housing 12 and the insert part 6.
  • the air flow 19 divides on its way between the working chamber 4 under vacuum chamber 3 in the air duct 20 into a first portion 19 ', which flows through the openings 7 in the insert 6 and a second portion 19 ", which flows through the bypass 21 between the Insert part 6 and the control housing 12 flows.
  • the flow through the bypass 21 thereby significantly influences the air resistance against the air flow 19 very difficult and with a great deal of effort can be precisely adhered to.
  • the interaction between the individual component tolerances and in particular the floating behavior of the control housing 12 when it cools down after the injection molding process allows the width s to vary in the range between 0 and several millimeters.
  • the portion 19 ′′ of the air flow 19 passing through the bypass 21 can even exceed the portion 19 '.
  • precise control of the return speed through air resistance either components have to be reworked in a complex manner or explicitly matching pairings Control housing 12 - insert part 6 with mutually favorable dimensional deviations are selected separately. This increases the assembly effort and the reject rate considerably.
  • FIG 5 shows an embodiment of the control housing 12 according to the invention in the area of the receiving seat for the insert part 6.
  • a circumferential step or a circumferential shoulder 13 offset radially inward is formed in the area of the receiving seat on the control housing 12 according to the invention.
  • On the shoulder 13 a circular cylindrical jacket surface 10 which is concentric to the central axis A is formed.
  • the support ribs 14 are integrally connected to the shoulder 13 axially in the actuating direction B.
  • FIG. 6 shows the air flow through the control housing 12 according to FIG. 5 in a return.
  • the insert part 6 has a radially outwardly facing, circular-cylindrical jacket surface 9.
  • a circular-cylindrical-ring-shaped constriction 8 is formed between the insert-part jacket surface 9 and the control housing jacket surface 10 the control housing 12 are still subject to manufacturing-related dimensional tolerances. Because the constriction 8 is independent of tolerances in the axial direction due to its circular cylindrical design, the remaining tolerances in the radial direction are much easier to control from a manufacturing point of view, so that the deviations from a desired nominal dimension can be kept within an acceptable range.
  • the narrow point 8 can be present as a sealing point or a throttle point.
  • the lateral surfaces 9 and 10 lie completely flat on top of one another, so that no air can pass through the constriction 8 and the entire air flow 19 passes exclusively through the openings 7 in the insert part 6.
  • a circular cylindrical gap with such a shape is formed between the lateral surfaces 9 and 10 narrow gap width that the resulting passage area through the constriction 8 is significantly smaller than the cumulative passage area through the openings 7 in the insert part 6. This state remains very reliably reproducible even without a separately increased production effort.
  • the constriction 8 can preferably be defined and generated as a standardized clearance fit JS11 / cd10 in accordance with ISO 286. This ensures that the maximum passage area for the air flow 19 through the constriction 8 is only a fraction of the passage area through the openings 7 in the insert, which enables the air resistance and thus the return speed to be adjusted with sufficient accuracy. At the same time, it is ensured that the insert 6 does not jam in the control housing 12, thereby simplifying assembly and avoiding tilting or tilting.
  • the support ribs 14 support the insert 6 axially against the direction of actuation B. If, as in the example shown, they end exactly radially inward in the lateral surface 10, they form a reliable support for the insert 6 in the radial direction, so that the surface pressure in the area of the constriction 8 and thus the risk of wear are reduced.
  • paragraph 13 shows the exemplary embodiment of the control housing 12 according to FIGS. 5 and 6 in the area of the constriction 8.
  • paragraph 13 is solidly designed for the benefit of simplified manufacture and increased stability.
  • FIG. 8 shows another embodiment of the control housing 12 according to the invention, in contrast to the embodiment according to FIGS be designed for example in the form of individual pockets in the spaces between the support ribs 14 or as a single circumferential recess or axial groove.
  • an accumulation of material is avoided in an area immediately adjacent to the jacket surface 10, as a result of which a particularly high dimensional accuracy of the jacket surface 10 can be achieved in an injection molding process.
  • the The invention is not limited to the embodiment shown, but also includes further, not shown, but functionally equivalent measures to avoid material accumulation, for example by forming a closed cavity in the wall of the control housing 120 in the vicinity of the lateral surface 10.

Landscapes

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

Abstract

L'invention se rapporte à un servofrein pneumatique (1) pour des véhicules à moteur, comprenant : - un boîtier de surpresseur (2), dont l'intérieur présente au moins une chambre à pression négative (3), à laquelle une pression négative peut être appliquée, et au moins une chambre de travail (4), qui peut être reliée à une atmosphère ambiante ; - au moins une liaison pneumatique entre la chambre à pression négative (3) et la chambre de travail (4), laquelle liaison pneumatique peut être commandée au moyen d'un ensemble vanne (5) ; et - au moins une partie d'insert (6) ayant au moins une ouverture axiale (7), à travers laquelle un flux d'air peut s'écouler de la chambre de travail (4) vers la chambre à pression négative (3). Selon l'invention, afin de pouvoir régler la vitesse de retour du servofrein (1) de manière particulièrement précise, économique et fiable et de manière reproductible, il est proposé qu'il y ait un point étroit (8) entre la partie insert (7) et le servofrein (1), lequel point étroit est situé entre une première surface latérale cylindrique circulaire (9) et une seconde surface latérale cylindrique circulaire (10), la première surface latérale cylindrique circulaire (9) étant formée sur la partie d'insert (7).
PCT/DE2021/200077 2020-06-18 2021-06-07 Servofrein ayant une liaison pneumatique définie WO2021254569A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE102020207538.7 2020-06-18
DE102020207538.7A DE102020207538A1 (de) 2020-06-18 2020-06-18 Bremskraftverstärker mit einer definierten pneumatischen Verbindung

Publications (1)

Publication Number Publication Date
WO2021254569A1 true WO2021254569A1 (fr) 2021-12-23

Family

ID=76502642

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/DE2021/200077 WO2021254569A1 (fr) 2020-06-18 2021-06-07 Servofrein ayant une liaison pneumatique définie

Country Status (2)

Country Link
DE (1) DE102020207538A1 (fr)
WO (1) WO2021254569A1 (fr)

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20040046445A1 (en) * 2000-12-14 2004-03-11 Ulysse Verbo Brake booster with high kick-off emergency valve
DE102006005218A1 (de) * 2005-04-15 2006-11-23 Continental Teves Ag & Co. Ohg Bremskraftverstärker
DE102006056674A1 (de) * 2006-11-06 2008-05-08 Continental Teves Ag & Co. Ohg Pneumatischer Bremskraftverstärker
DE102013218642A1 (de) 2012-09-17 2014-03-20 Continental Teves Ag & Co. Ohg Bremskraftverstärker

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102006033534A1 (de) 2006-04-25 2007-10-31 Continental Teves Ag & Co. Ohg Pneumatischer Bremskraftverstärker
DE102010002651A1 (de) 2010-03-08 2011-09-08 Continental Teves Ag & Co. Ohg Pneumatischer Bremskraftverstärker für eine Kraftfahrzeugbremsanlage

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20040046445A1 (en) * 2000-12-14 2004-03-11 Ulysse Verbo Brake booster with high kick-off emergency valve
DE102006005218A1 (de) * 2005-04-15 2006-11-23 Continental Teves Ag & Co. Ohg Bremskraftverstärker
DE102006056674A1 (de) * 2006-11-06 2008-05-08 Continental Teves Ag & Co. Ohg Pneumatischer Bremskraftverstärker
DE102013218642A1 (de) 2012-09-17 2014-03-20 Continental Teves Ag & Co. Ohg Bremskraftverstärker

Also Published As

Publication number Publication date
DE102020207538A1 (de) 2021-12-23

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