WO1999022974A2 - Housing part for a pneumatic brake booster - Google Patents
Housing part for a pneumatic brake booster Download PDFInfo
- Publication number
- WO1999022974A2 WO1999022974A2 PCT/EP1998/006935 EP9806935W WO9922974A2 WO 1999022974 A2 WO1999022974 A2 WO 1999022974A2 EP 9806935 W EP9806935 W EP 9806935W WO 9922974 A2 WO9922974 A2 WO 9922974A2
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- WIPO (PCT)
- Prior art keywords
- section
- housing
- brake cylinder
- body wall
- housing according
- Prior art date
Links
- 238000007789 sealing Methods 0.000 claims abstract description 12
- 230000000694 effects Effects 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 239000012080 ambient air Substances 0.000 description 1
- 238000004873 anchoring Methods 0.000 description 1
- 239000011324 bead Substances 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 238000004049 embossing Methods 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 239000007769 metal material Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000009423 ventilation Methods 0.000 description 1
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
- B60T13/567—Vacuum systems indirect, i.e. vacuum booster units characterised by constructional features of the casing or by its strengthening or mounting arrangements
Definitions
- the invention relates to a housing part for a pneumatic brake booster with the features of the preamble of claim 1.
- Such a housing part is known for example from DE-OS 28 45 794.
- the housing of the brake booster is made of thin sheet metal for weight reasons. Because this material thickness is not sufficient to reliably transfer braking reaction forces that occur during operation to a body wall, additional connecting bolts are provided. The connecting bolts are used for power transmission and thus at least partially replace the function of a housing with a thick wall.
- pneumatic brake boosters deform due to the pressure difference between the ambient pressure and the negative pressure in a vacuum chamber delimited by a movable wall. It has now been shown that the operational behavior of brake boosters with particularly thin-walled housings, that is to say with housing wall thicknesses of a few tenths of a millimeter, for example below 0.8 mm, is unsatisfactory both without but in particular also with connecting bolts.
- the loading of brake boosters with thin sheet metal material causes a deformation in the area of the attachment points of the master brake cylinder or in the area of the body wall the housing of the brake booster is attached.
- stiffening disks in the area of the anchoring point, with which the housing is locally reinforced. Both the manufacture and installation of these stiffening washers is, however, prohibited for reasons of cost.
- the embossing of beads in the housing part leads to an expensive, not rotationally symmetrical tool contour and therefore also to high costs.
- the object of the present invention is therefore to provide a housing made of thin sheet metal for a brake booster which can withstand the forces occurring during operation under all circumstances and, in particular under the pressure load caused by the ambient pressure, has no tendency to vent the vacuum chamber.
- the housing should also be easy to manufacture. This object is achieved with the characterizing features of claim 1 in that the contact surface (2) is spring-loaded completely or with at least one section (10) of the master brake cylinder and / or the body wall.
- the contact surface on the master brake cylinder to be fastened or the body wall is correctly positioned in any case.
- the solution to the problem is that the contact surface is in the fully assembled state under an elastic biasing force, which leads in particular to an increased sealing effect in the axial direction.
- FIG. 1 side view of a housing part in section and on a smaller scale
- FIG. 2 housing part fastened to a master brake cylinder flange on the scale as in FIG. 1;
- Fig. 3 partially cut-away side view of a known, conventional brake booster housing with a master cylinder attached.
- Fig. 1 shows a shell-shaped first housing part 1 for a brake booster.
- a housing for a brake booster consists of two housing parts which are arranged opposite one another and have at least one movable wall in their interior, so that each housing part 1, together with the movable wall, delimits at least one pneumatic valve.
- One of the two chambers, the so-called vacuum chamber, is permanently under vacuum in relation to the outside environment (and the pressure pu there).
- the housing part 1 has at least one contact surface 2 for attachment to a flange 3 of a master brake cylinder 4 or a body wall.
- the contact surface 2 is delimited by an opening 5, which serves for the passage of an actuating element, for example a control housing, and which is optionally guided in the radial direction on an annular collar 6.
- an actuating element for example a control housing
- the course of the cut in FIGS. 1 and 2 was chosen such that the fastening screws 7, 8 of the master brake cylinder 4 are visible.
- the arrangement according to the invention also in a brake booster with stiffening bolts (Tie rod) is applicable. It is only conceivable, for example, that a tie rod is provided in each case at a location of a fastening screw 7, 8 and extends through the interior of the housing in the axial direction.
- the contact surface 2 acts resiliently on the counter surface of the brake booster 4 or the body wall.
- the contact surface 2 has a first section 9 and a second section 10, the first section 9 being arranged parallel to the flange 3 and at right angles to an axis 12 even before the master brake cylinder 4 is fastened.
- the second section 10 stands for an axially resilient action on the master brake cylinder 4 or for an axially resilient action on the body wall to be fastened in the axial direction. It can also be seen that the two sections 9, 10 adjoin one another in the radial direction and, like the entire housing part 1 (with the exception of the bulge 11), are designed to be rotationally symmetrical to the axis 12.
- the second section 10 is cranked in relation to the first section 9 in such a way that the edge 13 which projects furthest in the axial direction is axially aligned with the collar 6.
- the angular connection of section 10 to collar 6 results in an increased spring rate.
- the deflection of the section 10 in the assembled state results in improved guidance and sealing of the actuation supply member on the collar 6, because the same is pressed closer to the circumference of the actuator.
- the second section 10 is bent at an obtuse angle () to the first section 9.
- Fig. 2 shows the housing part 1 with an attached, only partially drawn master brake cylinder 4.
- the section through the housing part 1 was chosen so that the fastening screws 7, 8 are visible.
- the two sections 9, 10 lie flat on the housing part 1 after fastening the master brake cylinder 4, so that the second section 10, at least in the area of its edge 13, resiliently acts on a counter surface 14 in the axial direction.
- a sealing element 15, for example in the manner of an O-ring is basically provided between the two contact surfaces, which is only indicated schematically in the drawing. It is essential that at least the most axially projecting edge 13 of the second section 10 rests axially resiliently against the master brake cylinder or the body wall, optionally with the interposition of the sealing element 15.
- Fig. 3 shows a generally known, partially cut brake booster with two housing parts master brake cylinder 4 attached to it, the inner parts of the brake booster and the master brake cylinder, which are not of interest, being omitted for clarity. Accordingly, the features of the invention are not provided.
- the vacuum chamber 21 delimited by the housing part 20 and the movable wall (not shown) is evacuated by means of the vacuum connection 22 and therefore there is a lower pressure inside than the ambient pressure pu.
- the acting pressure difference which is also effective in the gap area of the contact surface 23, the contact surface 23 collapses, in particular in the area of the sealing element 24, so that this has no sealing contact with the counter-sealing surface 25 of the flange 26.
- the collapse of the housing part 20 under the effect of the pressure difference leads to a reduction in the contact pressure of the sealing element 24 and, as a result, to a deteriorated sealing effect.
- the invention is particularly suitable for use in motor vehicle brake boosters with a housing made of thin sheet material, that is to say with wall thicknesses below approximately 0.8 mm.
- the invention is not limited to this, since multiple modifications of the invention in brake boosters with thicker sheet material are conceivable without departing from the basic idea of the invention.
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- Engineering & Computer Science (AREA)
- Transportation (AREA)
- Mechanical Engineering (AREA)
- Braking Systems And Boosters (AREA)
Abstract
Description
Gehäuseteil für einen pneumatischen BremskraftverstärkerHousing part for a pneumatic brake booster
Die Erfindung betrifft einen Gehäuseteil für einen pneumatischen Bremskraftverstärker mit den Merkmalen des Oberbegriffs des Patentanspruches 1.The invention relates to a housing part for a pneumatic brake booster with the features of the preamble of claim 1.
Ein derartiger Gehäuseteil ist beispielsweise aus der DE-OS 28 45 794 bekannt. Das Gehäuse des Bremskraftverstärkers besteht aus Gewichtsgründen aus dünnem Blech. Weil diese Materialdicke nicht ausreicht, um im Betrieb auftretende Brems- reaktionskräfte zuverlässig auf eine Karosseriewand zu übertragen, sind zusätzlich Verbindungsbolzen vorgesehen. Die Verbindungsbolzen dienen der Kraftübertragung und substituieren damit zumindest teilweise die Funktion eines Gehäuse mit dicker Wandstärke.Such a housing part is known for example from DE-OS 28 45 794. The housing of the brake booster is made of thin sheet metal for weight reasons. Because this material thickness is not sufficient to reliably transfer braking reaction forces that occur during operation to a body wall, additional connecting bolts are provided. The connecting bolts are used for power transmission and thus at least partially replace the function of a housing with a thick wall.
Generell verformen sich pneumatische Bremskraftverstärker infolge der Druckdifferenz zwischen dem Umgebungsdruck und dem Unterdruck in einer, durch eine bewegliche Wand begrenzten Vakuumkammer. Es hat sich nun gezeigt, daß das Betriebsverhalten von Bremskraftverstärkern mit besonders dünnwandigen Gehäusen, das heißt mit Gehäusewandstärken von wenigen Zehntelmillimetern beispielsweise unterhalb von 0,8 mm sowohl ohne, aber insbesondere auch mit Verbindungsbolzen nicht zufriedenstellend ist. Die Beanspruchung von Bremskraftverstärkern mit dünnem Blechwerkstoff bewirkt eine Verformung im Bereich der Befestigungsstellen des Hauptbremszylinders oder im Bereich der Karosseriewand, an der das Gehäuse des Bremskraftverstärkers befestigt ist. Diese Verformung führt dazu, daß die Anlage zwischen dem Bremskraftverstärker und dem zugeordneten Hauptbremszylinder oder der Karosseriewand entlastet wird, so daß sich zwischen den aneinander befestigten Bauteilen infolge einer Spaltstelle eine Undichtigkeit ergibt, durch die beispielsweise der Umgebungsluftdruck (pu) in die Vakuumkammer eindringen kann. Es besteht deshalb die Gefahr einer ungewollten Belüftung der Vakuumkammer.In general, pneumatic brake boosters deform due to the pressure difference between the ambient pressure and the negative pressure in a vacuum chamber delimited by a movable wall. It has now been shown that the operational behavior of brake boosters with particularly thin-walled housings, that is to say with housing wall thicknesses of a few tenths of a millimeter, for example below 0.8 mm, is unsatisfactory both without but in particular also with connecting bolts. The loading of brake boosters with thin sheet metal material causes a deformation in the area of the attachment points of the master brake cylinder or in the area of the body wall the housing of the brake booster is attached. This deformation leads to the fact that the system between the brake booster and the associated master brake cylinder or the body wall is relieved, so that there is a leak between the attached components as a result of a gap, through which, for example, the ambient air pressure (pu) can penetrate into the vacuum chamber. There is therefore a risk of unwanted ventilation of the vacuum chamber.
Zwar ist es bekannt, im Bereich der Verankerungsstelle sog. Versteifungsscheiben einzusetzen, mit denen das Gehäuse örtlich verstärkt wird. Sowohl Herstellung als auch Einbau dieser Versteifungsscheiben verbietet sich allerdings aus Kostengründen. Das Einprägen von Sicken in den Gehäuseteil führt zu einer teuren, weil nicht rotationssymmetrischen Werkzeugkontur und deshalb ebenfalls zu hohen Kosten.It is known to use so-called stiffening disks in the area of the anchoring point, with which the housing is locally reinforced. Both the manufacture and installation of these stiffening washers is, however, prohibited for reasons of cost. The embossing of beads in the housing part leads to an expensive, not rotationally symmetrical tool contour and therefore also to high costs.
Aufgabe der vorliegenden Erfindung ist es daher, ein aus dünnem Blech bestehendes Gehäuse für einen Bremskraftverstärker bereitzustellen, welches unter allen Umständen den im Betrieb auftretenden Kräften widersteht und insbesondere unter der Druckbeanspruchung durch den Umgebungsdruck keine Tendenzen zum Belüften der Vakuumkammer aufweist. Das Gehäuse soll ferner einfach herstellbar sein. Diese Aufgabe wird mit den kennzeichnenden Merkmalen des Patentanspruches 1 dadurch gelöst, daß die Anlagefläche (2) vollständig oder mit wenigstens einem Abschnitt (10) den Hauptbremszylinder und / oder die Karosseriewand federnd beaufschlagt.The object of the present invention is therefore to provide a housing made of thin sheet metal for a brake booster which can withstand the forces occurring during operation under all circumstances and, in particular under the pressure load caused by the ambient pressure, has no tendency to vent the vacuum chamber. The housing should also be easy to manufacture. This object is achieved with the characterizing features of claim 1 in that the contact surface (2) is spring-loaded completely or with at least one section (10) of the master brake cylinder and / or the body wall.
Erfindungsgemäß ergibt sich eine in jedem Fall korrekte Anlage der Anlagefläche an dem zu befestigenden Hauptbremszylinder oder der Karosseriewand. Im Prinzip besteht die Lösung der Aufgabe also darin, daß die Anlagefläche im vollständig montierten Zustand unter einer elastischen Vorspannkraft steht, welche insbesondere zu einer erhöhten Dichtwirkung in axialer Richtung führt.According to the invention, the contact surface on the master brake cylinder to be fastened or the body wall is correctly positioned in any case. In principle, the solution to the problem is that the contact surface is in the fully assembled state under an elastic biasing force, which leads in particular to an increased sealing effect in the axial direction.
Weitere Einzelheiten des Ausführungsbeispiels gehen aus Unteransprüchen im Zusammenhang mit der Zeichnung und der Beschreibung hervor.Further details of the exemplary embodiment emerge from subclaims in connection with the drawing and the description.
Das Ausführungsbeispiel der Erfindung wird nachstehend anhand der Zeichnung im einzelnen erläutert. In der Zeichnung zeigt:The embodiment of the invention is explained below with reference to the drawing. The drawing shows:
Fig. 1 Seitenansicht eines Gehäuseteils im Schnitt sowie in kleinerem Maßstab;Fig. 1 side view of a housing part in section and on a smaller scale;
Fig. 2 an einem Hauptbremszylinderflansch befestigter Gehäuseteil in dem Maßstab wie in Fig. 1; Fig. 3 teilweise aufgeschnittene Seitenansicht eines bekannten, konventionellen Bremskraftverstärkergehäuse mit daran befestigtem Hauptbremszylinder.FIG. 2 housing part fastened to a master brake cylinder flange on the scale as in FIG. 1; Fig. 3 partially cut-away side view of a known, conventional brake booster housing with a master cylinder attached.
Fig. 1 zeigt ein schalenförmiges erstes Gehäuseteil 1 für einen Bremskraftverstärker. Üblicherweise besteht ein Gehäuse für einen Bremskraftverstärker aus zwei Gehäuseteilen, die gegenüberliegend angeordnet sind und in ihrem Inneren mindestens eine bewegliche Wand aufweisen, so daß jeder Gehäuseteil 1 zusammen mit der beweglichen Wand mindestens eine pneumatische Kaiτimer begrenzt. Eine der beiden Kammern, die sogenannte Vakuumkammer steht permanent in Relation zu der Außenumgebung (und dem dortigen Druck pu) unter Unterdruck. Hinsichtlich der detaillierten Funktion des Bremskraftverstärkers wird auf den eingangs genannten Stand der Technik verwiesen. Der Gehäuseteil 1 weist schließlich mindestens eine Anlagefläche 2 zur Befestigung an einem Flansch 3 eines Hauptbremszylinders 4 oder einer Karosseriewand auf. Nach radial innen wird die Anlagefläche 2 von einer Öffnung 5 begrenzt, die dem Durchtritt eines Betätigungsglieds, beispielsweise eines Steuergehäuses, dient und welches ggf. in radialer Richtung an einem ringförmigen Kragen 6 geführt ist. Insgesamt wurde der Schnittverlauf in den Fig. 1 und 2 derart gewählt, daß die Befestigungsschrauben 7,8 des Hauptbremszylinders 4 sichtbar sind. Es versteht sich, daß die erfindungsgemäße Anordnung auch bei einem Bremskraftverstärker mit Versteifungsbolzen (Zuganker) anwendbar ist. Nur beispielsweise ist es denkbar, daß jeweils ein Zuganker an einer Stelle einer Befestigungsschraube 7,8 vorgesehen ist und das Innere des Gehäuse in axialer Richtung durchgreift. Erfindungsgemäß beaufschlagt die Anlagefläche 2 die Gegenfläche des Brems- kraftverstärkers 4 oder die Karosseriewand federnd.Fig. 1 shows a shell-shaped first housing part 1 for a brake booster. Usually, a housing for a brake booster consists of two housing parts which are arranged opposite one another and have at least one movable wall in their interior, so that each housing part 1, together with the movable wall, delimits at least one pneumatic valve. One of the two chambers, the so-called vacuum chamber, is permanently under vacuum in relation to the outside environment (and the pressure pu there). With regard to the detailed function of the brake booster, reference is made to the prior art mentioned at the beginning. Finally, the housing part 1 has at least one contact surface 2 for attachment to a flange 3 of a master brake cylinder 4 or a body wall. Radially inward, the contact surface 2 is delimited by an opening 5, which serves for the passage of an actuating element, for example a control housing, and which is optionally guided in the radial direction on an annular collar 6. Overall, the course of the cut in FIGS. 1 and 2 was chosen such that the fastening screws 7, 8 of the master brake cylinder 4 are visible. It is understood that the arrangement according to the invention also in a brake booster with stiffening bolts (Tie rod) is applicable. It is only conceivable, for example, that a tie rod is provided in each case at a location of a fastening screw 7, 8 and extends through the interior of the housing in the axial direction. According to the invention, the contact surface 2 acts resiliently on the counter surface of the brake booster 4 or the body wall.
Der Fig. 1 ist nun zu entnehmen, daß die Anlagefläche 2 einen ersten Abschnitt 9 und einen zweiten Abschnitt 10 aufweist, wobei der erste Abschnitt 9 bereits vor der Befestigung des Hauptbremszylinders 4 parallel zu dem Flansch 3 sowie rechtwinklig zu einer Achse 12 angeordnet ist. Der zweite Abschnitt 10 steht für eine axial federnde Beaufschlagung des Hauptbremszylinders 4 oder aber für eine axial federnde Beaufschlagung der zu befestigenden Karosseriewand in axialer Richtung vor. Es ist ferner ersichtlich, daß die beiden Abschnitte 9,10 in radialer Richtung aneinander anschließen, und wie der gesamte Gehäuseteil 1 (mit Ausnahme der Ausbuchtung 11) rotationssymmetrisch zu der Achse 12 ausgeführt sind. Weiterhin ist der zweite Abschnitt 10 in Relation zu dem ersten Abschnitt 9 derart abgekröpft, daß der in axialer Richtung am weitesten vorstehende Rand 13 axial mit dem Kragen 6 fluchtet. Durch die winklige Anbindung des Abschnittes 10 an den Kragen 6 ergibt sich eine erhöhte Federrate. Ferner ergibt sich durch das einfedern des Abschnittes 10 im montierten Zustand eine verbesserte Führung und Abdichtung des genannten Betäti- gungsglieds an dem Kragen 6, weil derselbe näher an den Umfang des Betätigungsglieds gedrückt wird. Es erfolgt also gleichzeitig eine Verbesserung der Abdichtung in axialer Richtung wie auch in radialer Richtung am Umfang des Steuergehäuses. Grundsätzlich ist der zweite Abschnitt 10 in stumpfem Winkel ( ) zu dem ersten Abschnitt 9 abgekröpft.1 that the contact surface 2 has a first section 9 and a second section 10, the first section 9 being arranged parallel to the flange 3 and at right angles to an axis 12 even before the master brake cylinder 4 is fastened. The second section 10 stands for an axially resilient action on the master brake cylinder 4 or for an axially resilient action on the body wall to be fastened in the axial direction. It can also be seen that the two sections 9, 10 adjoin one another in the radial direction and, like the entire housing part 1 (with the exception of the bulge 11), are designed to be rotationally symmetrical to the axis 12. Furthermore, the second section 10 is cranked in relation to the first section 9 in such a way that the edge 13 which projects furthest in the axial direction is axially aligned with the collar 6. The angular connection of section 10 to collar 6 results in an increased spring rate. Furthermore, the deflection of the section 10 in the assembled state results in improved guidance and sealing of the actuation supply member on the collar 6, because the same is pressed closer to the circumference of the actuator. At the same time there is an improvement in the sealing in the axial direction as well as in the radial direction on the circumference of the control housing. Basically, the second section 10 is bent at an obtuse angle () to the first section 9.
Fig. 2 zeigt den Gehäuseteil 1 mit einem daran befestigten, nur teilweise gezeichneten Hauptbremszylinder 4. Wie bereits gesagt, wurde der Schnittverlauf durch das Gehäuseteil 1 so gewählt, daß die Befestigungsschrauben 7,8 sichtbar sind. ie die Zeichnung zeigt, liegen die beiden Abschnitte 9,10 nach der Befestigung des Hauptbremszylinders 4 an dem Gehäuseteil 1 plan an, so daß der zweite Abschnitt 10 zumindest im Bereich seines Randes 13 eine Gegenfläche 14 in axialer Richtung federnd beaufschlagt. Es bleibt ferner darauf hinzuweisen, daß grundsätzlich zwischen den beiden Kontaktflächen ein Dichtungselement 15, beispielsweise nach Art eines O-Ring vorgesehen ist, welches in der Zeichnung lediglich schematisiert angedeutet ist. Wesentlich ist, daß zumindest der am weitesten axial vorstehende Rand 13 des zweiten Abschnitts 10 gegebenenfalls unter Zwischenordnung des Dichtungselementes 15 axial federnd an dem Hauptbremszylinder oder der Karosseriewand anliegt.Fig. 2 shows the housing part 1 with an attached, only partially drawn master brake cylinder 4. As already said, the section through the housing part 1 was chosen so that the fastening screws 7, 8 are visible. ie the drawing shows, the two sections 9, 10 lie flat on the housing part 1 after fastening the master brake cylinder 4, so that the second section 10, at least in the area of its edge 13, resiliently acts on a counter surface 14 in the axial direction. It should also be pointed out that a sealing element 15, for example in the manner of an O-ring, is basically provided between the two contact surfaces, which is only indicated schematically in the drawing. It is essential that at least the most axially projecting edge 13 of the second section 10 rests axially resiliently against the master brake cylinder or the body wall, optionally with the interposition of the sealing element 15.
Fig. 3 zeigt einen grundsätzlich bekannten, zum Teil aufgeschnittenen Bremskraftverstärker aus zwei Gehäuseteilen mit daran befestigtem Hauptbremszylinder 4 wobei die nicht interessierenden innenteile des Bremskraftverstärkers und des Hauptbremszylinders der Klarkeit wegen weggelassen wurden. Entsprechend sind die erfindungsgemäßen Merkmale nicht vorgesehen. Die durch den Gehäuseteil 20 und die nicht dargestellte bewegliche Wand begrenzte Vakuumkammer 21 ist mittels des Vakuumanschlusses 22 evakuiert und es herrscht deshalb in ihrem Inneren ein gegenüber dem Umgebungsdruck pu geringerer Druck. Infolge der wirkenden Druckdifferenz, welche auch in dem Spaltbereich der Anlagefläche 23 wirksam ist, kommt es zu einem Einfallen der Anlagefläche 23 insbesondere im Bereich des Dichtelementes 24, so daß dieses keinen dichtenden Kontakt zu der Gegendichtflache 25 des Flanschs 26 besitzt. In jedem Falle führt das Einfallen des Gehäuseteils 20 unter der Wirkung der Druckdifferenz zu einer Verringerung der Anpreßkraft des Dichtelementes 24 und infolge dessen zu einer verschlechterten Dichtungswirkung.Fig. 3 shows a generally known, partially cut brake booster with two housing parts master brake cylinder 4 attached to it, the inner parts of the brake booster and the master brake cylinder, which are not of interest, being omitted for clarity. Accordingly, the features of the invention are not provided. The vacuum chamber 21 delimited by the housing part 20 and the movable wall (not shown) is evacuated by means of the vacuum connection 22 and therefore there is a lower pressure inside than the ambient pressure pu. As a result of the acting pressure difference, which is also effective in the gap area of the contact surface 23, the contact surface 23 collapses, in particular in the area of the sealing element 24, so that this has no sealing contact with the counter-sealing surface 25 of the flange 26. In any case, the collapse of the housing part 20 under the effect of the pressure difference leads to a reduction in the contact pressure of the sealing element 24 and, as a result, to a deteriorated sealing effect.
Es bleibt abschließend darauf hinzuweisen, daß sich die Erfindung zwar insbesondere zum Einsatz bei Kraftfahrzeug- Bremskraftverstärkern mit Gehäuse aus dünnem Blechmaterial eignet, also bei Wanddicken unterhalb etwa 0,8 mm. Ganz grundsätzlich ist die Erfindung allerdings nicht darauf beschränkt, denn es sind vielfache Abwandlungen der Erfindung bei Bremskraftverstärkern mit dickerem Blechwerkstoff denkbar, ohne den Grundgedanken der Erfindung zu verlassen. In conclusion, it should be pointed out that the invention is particularly suitable for use in motor vehicle brake boosters with a housing made of thin sheet material, that is to say with wall thicknesses below approximately 0.8 mm. In principle, however, the invention is not limited to this, since multiple modifications of the invention in brake boosters with thicker sheet material are conceivable without departing from the basic idea of the invention.
Claims
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| EP98961121A EP1027238A2 (en) | 1997-11-03 | 1998-11-03 | Housing part for a pneumatic brake booster |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19748492.1 | 1997-11-03 | ||
| DE1997148492 DE19748492A1 (en) | 1997-11-03 | 1997-11-03 | Housing part for a pneumatic brake booster |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| WO1999022974A2 true WO1999022974A2 (en) | 1999-05-14 |
| WO1999022974A3 WO1999022974A3 (en) | 1999-07-29 |
| WO1999022974A9 WO1999022974A9 (en) | 1999-09-10 |
Family
ID=7847446
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| PCT/EP1998/006935 WO1999022974A2 (en) | 1997-11-03 | 1998-11-03 | Housing part for a pneumatic brake booster |
Country Status (3)
| Country | Link |
|---|---|
| EP (1) | EP1027238A2 (en) |
| DE (1) | DE19748492A1 (en) |
| WO (1) | WO1999022974A2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6686465B2 (en) | 2000-05-03 | 2004-02-03 | Basf Aktiengesellschaft | Preparation of cyclic lactams |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2481216A1 (en) * | 1980-04-25 | 1981-10-30 | Dba | SERVO-ENGINE ASSEMBLY FOR BRAKE ASSEMBLY WITH FASTENING REINFORCEMENT |
| DE3401402C2 (en) * | 1984-01-17 | 1993-09-30 | Teves Gmbh Alfred | Vacuum brake booster |
| JP3214772B2 (en) * | 1994-01-25 | 2001-10-02 | 日信工業株式会社 | Booster shell reinforcement structure for negative pressure booster |
| DE19528860A1 (en) * | 1995-08-05 | 1997-02-06 | Teves Gmbh Alfred | Pneumatic brake amplifier with plastic moulded casing - has bottom surface with region round screws having outward plastic deformation which corresponds to given force |
| DE29514063U1 (en) * | 1995-09-01 | 1997-01-09 | Lucas Industries P.L.C., Solihull, West Midlands | Brake booster / master cylinder unit with connecting bolts |
-
1997
- 1997-11-03 DE DE1997148492 patent/DE19748492A1/en not_active Withdrawn
-
1998
- 1998-11-03 EP EP98961121A patent/EP1027238A2/en not_active Withdrawn
- 1998-11-03 WO PCT/EP1998/006935 patent/WO1999022974A2/en not_active Application Discontinuation
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6686465B2 (en) | 2000-05-03 | 2004-02-03 | Basf Aktiengesellschaft | Preparation of cyclic lactams |
Also Published As
| Publication number | Publication date |
|---|---|
| WO1999022974A3 (en) | 1999-07-29 |
| EP1027238A2 (en) | 2000-08-16 |
| WO1999022974A9 (en) | 1999-09-10 |
| DE19748492A1 (en) | 1999-07-15 |
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