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WO1997028031A1 - Slip-controlled hydraulic brake system with charge pump - Google Patents

Slip-controlled hydraulic brake system with charge pump Download PDF

Info

Publication number
WO1997028031A1
WO1997028031A1 PCT/EP1997/000285 EP9700285W WO9728031A1 WO 1997028031 A1 WO1997028031 A1 WO 1997028031A1 EP 9700285 W EP9700285 W EP 9700285W WO 9728031 A1 WO9728031 A1 WO 9728031A1
Authority
WO
WIPO (PCT)
Prior art keywords
valve
connection
pressure
brake
charge pump
Prior art date
Application number
PCT/EP1997/000285
Other languages
German (de)
French (fr)
Inventor
Helmut Steffes
Original Assignee
Itt Manufacturing Enterprises, Inc.
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 Manufacturing Enterprises, Inc. filed Critical Itt Manufacturing Enterprises, Inc.
Priority to JP9527275A priority Critical patent/JP2000503933A/en
Priority to EP97901582A priority patent/EP0874748A1/en
Publication of WO1997028031A1 publication Critical patent/WO1997028031A1/en

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
    • B60T8/00—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force
    • B60T8/32—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration
    • B60T8/34—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration having a fluid pressure regulator responsive to a speed condition
    • B60T8/48—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration having a fluid pressure regulator responsive to a speed condition connecting the brake actuator to an alternative or additional source of fluid pressure, e.g. traction control systems
    • B60T8/4809—Traction control, stability control, using both the wheel brakes and other automatic braking systems
    • B60T8/4827—Traction control, stability control, using both the wheel brakes and other automatic braking systems in hydraulic brake systems
    • B60T8/4863—Traction control, stability control, using both the wheel brakes and other automatic braking systems in hydraulic brake systems closed systems
    • B60T8/4872—Traction control, stability control, using both the wheel brakes and other automatic braking systems in hydraulic brake systems closed systems pump-back systems
    • B60T8/4881—Traction control, stability control, using both the wheel brakes and other automatic braking systems in hydraulic brake systems closed systems pump-back systems having priming means
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
    • B60T8/00—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force
    • B60T8/32—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration
    • B60T8/34—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration having a fluid pressure regulator responsive to a speed condition
    • B60T8/341—Systems characterised by their valves

Definitions

  • the present invention is based on a slip-controlled hydraulic brake system according to the preamble of claim 1.
  • brake systems are known, for example, from DE 42 32 311 Cl and from DE 43 29 139 Cl. In both cases, these are brake systems which are suitable both for brake slip control and for automatic brake actuation.
  • During a brake slip control they operate according to the return feed principle.
  • the two return pumps of the anti-lock control are used as pressure sources for the automatic activation of the wheel brakes.
  • precharge cylinders designed in the manner of single-circuit master cylinders are provided, the trailing chambers of which are connected to a pressure outlet of the pedal-operated master cylinder.
  • the pressure outputs of the precharge cylinders can be connected to the brake line of each brake circuit and to the suction side of its return pump by means of a control valve arrangement.
  • the pressure outputs of the return pumps are shut off against the pressure outputs of the precharge cylinders and the latter on the suction sides of the by switching the control valve arrangement Return pumps connected.
  • the precharge cylinders are both actuated by a common charge pump, which acts on the piston surfaces of the precharge cylinder with their delivery pressure.
  • the suction side of the charge pump is connected to the reservoir.
  • a seat valve is closed by the pressure of the charge pump, which blocks the connection from the pedal-operated master cylinder to the wheel brakes.
  • the precharge cylinders of the two publications differ in that DE 42 32 311 Cl has two separate precharge cylinders, each with a drive pressure chamber, the drive pressure chambers being connected to the charge pump via a common pressure line, while in DE 43 29 139 the Both precharge cylinders have a common, centrally arranged drive pressure chamber, which is connected to the pressure side of the charge pump. As a result, the corresponding pistons of this precharging device move apart as soon as the charge pump builds up pressure.
  • the object of the present invention is to provide a brake system according to the preamble of claim 1 when using a common pump for precharging the return pumps, in which two separate static brake circuits are retained in accordance with the statutory provisions and are inexpensive while maintaining closed circuits static brake circuits there is the possibility of pre-charging.
  • the principle of the present invention is to arrange the charge pump above the master cylinder and to block the connection between the master cylinder and the reservoir by means of a hydraulically operated switching valve.
  • the switching valve has two active surfaces: the delivery pressure of the charge pump acts directly on the first active surface in the closing direction and, after overcoming a non-return valve on the part of the follow-up connection of the master cylinder, in the opening direction on the second active surface.
  • the pressure acting in the closing direction is always greater than the pressure acting in the opening direction and reduced by the admission pressure of the check valve, as long as the isolating valve in the brake line remains closed.
  • the isolating valve When an active braking is ended, the isolating valve is opened so that the brake pressure propagates through the unactuated master cylinder to the switching valve and opens it.
  • An electronic control logic and electrical lines to the switching valve are therefore not required.
  • Such an arrangement of the charge pump above the master cylinder is not limited to brake systems in which precharging is required in both brake circuits, but can also be used for brake systems in which only the return pump of a brake circuit needs to be precharged .
  • the return pump is optimized for achieving high delivery pressures and can therefore only deliver a comparatively small volume flow.
  • the charge pump delivers a maximum volume flow at low pressures. This is particularly important when initiating an automatic braking process if the air clearances of the wheel brakes in question must first be overcome. This applies to both self-priming and non-self-priming return pumps.
  • FIG. 1 shows a brake system according to the invention with a hydraulically actuated switching valve, only the trailing space of the first brake circuit being precharged
  • FIG. 2 shows a constructive solution for a hydraulically operated switching valve according to FIG. 1.
  • the brake line 3 runs from the master cylinder 1 via an electromagnetically actuated, normally open isolating valve 4 and is divided into two brake branches 5 and 6.
  • the brake branch 5 leads via the electromagnetic actuated, normally open inlet valve 7 to the wheel brake 8, while the brake branch 6 leads via a likewise normally open, electromagnetically operated inlet valve 9 to the wheel brake 10.
  • a return line 12 or 14 leads from each of the two wheel brakes 8 and 10 to a low-pressure accumulator 15.
  • the return lines 12 and 14 are each provided with an outlet valve 11 and 13, respectively, which are electromagnetically operated, normally closed 2/2 Directional valves are designed.
  • the low-pressure accumulator 15 is connected to the suction side of a return pump 17 via a suction line 16, which will be referred to later as the second suction line connected.
  • the first suction line 18 of the return pump 17 is connected to the brake line 3 between the master cylinder 1 and the isolation valve 4.
  • the first suction line is provided with a changeover valve 19, which is an electromagnetically actuated, normally closed 2/2-way valve.
  • the return pump 17 is connected with its pressure side via a pressure line 20 to the brake line 3 between the separating valve 4 on the one hand and the inlet valves 7 and 9 on the other hand.
  • the return pump 17 is designed to be self-priming, but has a pre-charging device above the master cylinder 1.
  • the connection between the reservoir 22 and the wheel brakes is interrupted by the pressure chambers of the master cylinder 1.
  • the master cylinder pressure on the suction side of the return pump is available when the changeover valve 19 is actuated, so that preloading is not necessary.
  • the brake pedal 21 is not actuated, the connection between the reservoir 22 and the brake line 3 is opened through the master cylinder 1.
  • the master cylinder 1 has two container connections 23 and 24, which are assigned to two master cylinder connections 25 and 26 of the storage container.
  • a switching valve 27 is inserted, a pressure-free, hydraulically operated 2/2-way valve.
  • the connecting line between the switching valve 27 and the follow-up connection 23 is connected to the pressure side of a charge pump 28 via a check valve 31, which has a pre-pressure of approximately 1 bar.
  • the suction side of the charge pump 28 is on the reservoir 22 connected. This arrangement means that the charge pump 28 and the switching valve 27 are connected in parallel.
  • the switching valve 27 is acted upon by the delivery pressure of the charge pump 28 in the closing direction, while the pressure at the follow-up connection 23 acts in the opening direction of the switching valve 27.
  • the pressure at the follow-up connection 23 is always lower than that on the pressure side of the charge pump 28 during active braking with the isolating valve 4 closed, which keeps the brake pressure in the wheel brakes 8 and 10, so that the switching valve is closed in such cases.
  • the effective area in the opening direction is chosen to be smaller than that in the closing direction, as will be explained later with reference to FIG. 2.
  • the delivery pressure of the charge pump 28 passes through the master cylinder 1, the brake line 3 and the first suction line 18 directly to the suction side of the return pump 17.
  • the check valve 4 is connected in a known manner in parallel with a check valve 29, through which the precharge pressure directly into the wheel brakes 8 and 10 arrives, even if the isolating valve is closed for the purpose of automatic braking.
  • the air play of the brakes can be quickly overcome.
  • the pressure in the wheel brakes increases to the precharge pressure. A further pressure build-up can then only take place with the help of the return pump.
  • a pressure limiting valve 30 is arranged parallel to the switching valve 27 and has an opening pressure of approximately 10 bar, at which the pressure side of the charge pump 28 is connected to the reservoir 22.
  • this pressure limiting valve 30 can also be replaced by one parallel to the charge pump.
  • the brake system shown is preloaded via the overrun space of the first brake circuit. The inflow of pressure medium fills the first brake circuit I, but also displaces the intermediate piston of the master cylinder 1. In this way, the second brake circuit II is also charged with the boost pressure.
  • FIG. 2a shows a constructive solution for a hydraulically actuated switching valve 27 according to FIG. 1.
  • the arrangement according to FIG. 2a has two parallel housing bores 41 and 42 in a housing 40.
  • the pressure limiting valve 30 is accommodated in the narrower bore 41, which has a pre-pressure of approximately 10 bar, while the switching valve 27 with an integrated check valve 31 is built into the housing bore 42 of larger diameter.
  • a vertical bore 43 running perpendicular to the two housing bores 41 and 42 connects the two inlets of the check valve 31 and the pressure limiting valve 30 to the pressure side of the charge pump 28.
  • the switching valve 27 has a piston 44, one end face 45 of which is exposed to the delivery pressure of the charge pump 28.
  • the other end of the piston 45 has a step 46, which is biased by a compression spring 47 to the pressure side of the loading pump 28.
  • An extension 48 of smaller diameter carries a sealing ring 49 as a valve closing member, which cooperates with a valve seat 50 designed as a conical taper of the housing bore 42.
  • the end of the extension 48 projects into a narrower section 51 of the bore 42 and has notches 52 on its circumference, which even with axial guidance of the extension 48, a volume flow along this extension is permitted.
  • the piston 44 is axially pierced and accommodates the check valve 31 centrally in its interior, which allows a pressure medium flow from the pressure side of the charge pump 28.
  • a pressure medium outlet 53 is created, which is connected to the wake up port 23.
  • a further connecting bore from the housing bore 42 at the outlet of the pressure relief valve 30 along to the container connection 25 of the storage container 22.
  • the housing bores 41 and 42 are shown to the right in relation to the atmosphere locked up.
  • an elastic sleeve 54 is inserted into the housing bore 41, which is held sealingly in the housing 40 by means of a pressed-in ball 55.
  • the housing bore 42 is closed by means of a cover 56 which is caulked to the housing 40 in a pressure-tight manner.
  • the cover 56 has axial extensions which form a stop for the piston 44 which is fixed to the housing.
  • the arrangement according to FIG. 2a works as follows: the charge pump 28 is switched on during active braking. The delivery pressure moves the piston 44 to the left until the sealing ring 49 comes into contact with the valve seat 50 and the switching valve 27 closes. From a bar overpressure on the part of the charge pump 28, the pressure medium flows via the check valve 31 to the follow-up connection 23 of the master cylinder. If the full delivery volume of the charge pump is not within the brake system recorded, this flows through the pressure regression valve 30 from 10 bar overpressure into the storage container 22. At the end of active braking, the return pump 17 feeds the pressure medium volume of the brake circuit I back into the master cylinder 1.

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

Abstract

For pre-charging the self-priming return pumps (17) in a slip-controlled brake system, e.g. at low temperatures, the following arrangement is proposed: a charge pump (28) fitted between the reservoir (22) and master cylinder (1) pumps fluid via a return valve into a feed connection (23) of the master cylinder (1); the fluid reaches the inlet side of the return pumps (17) by reversing an electromagnetic reversing valve (19) and an electromagnetic divider valve (4). For normal braking, a connection is provided between the reservoir (22) and master cylinder (1) and has an on-off valve (27). The on-off valve (27) is hydraulically operated and is subjected to the pumping pressure of the charge pump (28) in the closure direction and to the pressure on the reservoir connection (23) in the opening direction.

Description

Schlupfgeregelte hydraulische Bremsanlage mit LadepumpeSlip-controlled hydraulic brake system with charge pump
Die vorliegende Erfindung geht aus von einer schlupfgeregel¬ ten hydraulischen Bremsanlage gemäß dem Oberbegriff des An¬ spruchs 1. Derartige Bremsanlagen sind beispielsweise aus der DE 42 32 311 Cl und aus der DE 43 29 139 Cl bekannt. In bei¬ den FäLlen handelt es sich um Bremsanlagen, die sowohl zur Bremsschlupfregelung als auch zur automatischen Bremsbetäti¬ gung geeignet sind. Während einer Bremsschlupfregelung arbei¬ ten sie nach dem Rückförderprinzip. Zur selbsttätigen Akti¬ vierung der Radbremsen werden als Druckquellen die beiden Rückförderpumpen der Blockierschutzregelung genutzt. Zur Un¬ terstützung des Ansaugens dieser Rückförderpumpen sind in der Art von Einkreishauptzylindern ausgebildete Vorladezylinder vorgesehen, deren Nachlaufräume mit je einem Druckausgang des pedalbetätigten Hauptzylinders verbunden sind. Mittels einer Steuerventilanordnung sind die Druckausgänge der Vorladezy¬ linder an die Bremsleitung je eines Bremskreises und an die Saugseite seiner Rückförderpumpe anschließbar. Bei einer selbsttätigen Aktivierung der Radbremsen (Aktivbremsung) wer¬ den durch Umschaltung der Steuerventilanordnung die Druck¬ ausgänge der Rückförderpumpen gegen die Druckausgänge der Vorladezylinder abgesperrt und letztere an die Saugseiten der Rückförderpumpen angeschlossen. Die Vorladezylinder werden beide von einer gemeinsamen Ladepumpe betätigt, welche mit ihrem Förderdruck Kolbenflächen der Vorladezylinder beauf¬ schlagt. Die Ladepumpe ist mit ihrer Saugseite an den Vor¬ ratsbehälter angeschlossen. Durch den Druck der Ladepumpe wird zunächst, wie bei einem Hauptzylinder, ein Sitzventil geschlossen, welches die Verbindung vom pedalbetätigten Hauptzylinder zu den Radbremsen sperrt. Durch weitere Ver¬ schiebung eines Kolbens wird dann in der Bremsleitung ein Druck aufgebaut, welcher auch an der Saugseite der Rückför¬ derpumpe zur Verfügung steht. Die Vorladezylinder der beiden Druckschriften unterscheiden sich dadurch, daß in der DE 42 32 311 Cl zwei separate Vorladezylinder mit je einem An¬ triebsdruckraum vorhanden sind, wobei die Antriebsdrucfträume über eine gemeinsame Druckleitung mit der Ladepumpe verbunden sind, während in der DE 43 29 139 die beiden Vorladezylinder einen gemeinsamen, mittig angeordneten Antriebsdruckraum auf¬ weisen, welcher an die Druckseite der Ladepumpe angeschlossen ist. Hierdurch bewegen sich die entsprechenden Kolben dieser Vorladeeinrichtung auseinander, sobald die Ladepumpe Druck aufbaut. Derartige Anordnungen haben den Vorteil, daß trotz einer Vorladung aus dem Vorratsbehälter geschlossene stati¬ sche Bremskreise vorliegen, d.h. daß es außer dem Weg über die Zentralventile und Manschettendichtungen des Hauptzylin¬ ders keine Möglichkeit des Druckmittelaustauschs zwischen Vorratsbehälter und statischen Bremskreisen gibt. Die Druck¬ seite der Ladepumpe ist nämlich von den eigentlichen Brems¬ kreisen durch Trennkolben getrennt. Andererseits erfordert dies eine relativ aufwendige Konstruktion der Vorladezylin¬ der, die den Preis einer derartigen Bremsanlage in die Höhe treibt. Daher besteht die Aufgabe der vorliegenden Erfindung darin, bei Verwendung einer gemeinsamen Pumpe zur Vorladung der Rückförderpumpen eine Bremsanlage gemäß dem Oberbegriff des Anspruchs 1 zu schaffen, bei welcher gemäß den gesetzlichen Vorschriften zwei voneinander getrennte statische Bremskreise erhalten bleiben und auf preiswerte Weise unter Erhaltung von geschlossenen statischen Bremskreisen die Möglichkeit zur Vorladung besteht.The present invention is based on a slip-controlled hydraulic brake system according to the preamble of claim 1. Such brake systems are known, for example, from DE 42 32 311 Cl and from DE 43 29 139 Cl. In both cases, these are brake systems which are suitable both for brake slip control and for automatic brake actuation. During a brake slip control, they operate according to the return feed principle. The two return pumps of the anti-lock control are used as pressure sources for the automatic activation of the wheel brakes. In order to support the suction of these return pumps, precharge cylinders designed in the manner of single-circuit master cylinders are provided, the trailing chambers of which are connected to a pressure outlet of the pedal-operated master cylinder. The pressure outputs of the precharge cylinders can be connected to the brake line of each brake circuit and to the suction side of its return pump by means of a control valve arrangement. When the wheel brakes are activated automatically (active braking), the pressure outputs of the return pumps are shut off against the pressure outputs of the precharge cylinders and the latter on the suction sides of the by switching the control valve arrangement Return pumps connected. The precharge cylinders are both actuated by a common charge pump, which acts on the piston surfaces of the precharge cylinder with their delivery pressure. The suction side of the charge pump is connected to the reservoir. As with a master cylinder, a seat valve is closed by the pressure of the charge pump, which blocks the connection from the pedal-operated master cylinder to the wheel brakes. By further displacement of a piston, a pressure is then built up in the brake line, which pressure is also available on the suction side of the return pump. The precharge cylinders of the two publications differ in that DE 42 32 311 Cl has two separate precharge cylinders, each with a drive pressure chamber, the drive pressure chambers being connected to the charge pump via a common pressure line, while in DE 43 29 139 the Both precharge cylinders have a common, centrally arranged drive pressure chamber, which is connected to the pressure side of the charge pump. As a result, the corresponding pistons of this precharging device move apart as soon as the charge pump builds up pressure. Such arrangements have the advantage that there are closed static brake circuits in spite of a pre-charge from the reservoir, ie there is no possibility of exchanging pressure medium between the reservoir and static brake circuits apart from the way through the central valves and sleeve seals of the main cylinder. The pressure side of the charge pump is namely separated from the actual brake circuits by separating pistons. On the other hand, this requires a relatively complex construction of the precharge cylinder, which drives up the price of such a brake system. Therefore, the object of the present invention is to provide a brake system according to the preamble of claim 1 when using a common pump for precharging the return pumps, in which two separate static brake circuits are retained in accordance with the statutory provisions and are inexpensive while maintaining closed circuits static brake circuits there is the possibility of pre-charging.
Diese Aufgabe wird gelöst in Verbindung mit den kennzeichnen¬ den Merkmalen des Anspruchs 1. Das Prinzip der vorliegenden Erfindung besteht darin, die Ladepumpe oberhalb des Haupt¬ zylinders anzuordnen und mittels eines hydraulisch betätigten Schaltventils die Verbindung zwischen dem Hauptzylinder und dem Vorratsbehälter zu sperren. Das Schaltventil weist dazu zwei Wirkflächen auf: Der Förderdruck der Ladepumpe wirkt in Schließrichtung direkt auf die erste Wirkfläche ein und nach Überwindung eines Rückschlagventils von seiten des Nachlauf¬ anschlusses des Hauptzylinders in Öffnungsrichtung auf die zweite Wirkfläche. Hierdurch ist bei einer Aktivbremsung der in Schließrichtung wirkende Druck immer größer als der in Öffnungsrichtung wirkende,um den Vordruck des Rückschlagven¬ tils geminderte Druck, solange das Trennventil in der Brems¬ leitung geschlossen bleibt. Bei Beendigung einer Aktivbrem¬ sung wird das Trennventil geöffnet, so daß sich der Brems¬ druck durch den unbetätigten Hauptzylinder zum Schaltventil fortpflanzt und dieses öffnet. Eine elektronische Ansteuerlo- gik und elektrische Leitungen zum Schaltventil werden also nicht benötigt. Eine derartige Anordnung der Ladepumpe oberhalb des Haupt¬ zylinders bleibt dabei nicht auf solche Bremsanlagen be¬ schränkt, bei welchen in beiden Bremskreisen eine Vorladung erforderlich ist, sondern ist auch für solche Bremsanlagen verwendbar, in denen nur die Rückförderpumpe eines Bremskrei¬ ses vorgeladen werden muß.This object is achieved in connection with the characterizing features of claim 1. The principle of the present invention is to arrange the charge pump above the master cylinder and to block the connection between the master cylinder and the reservoir by means of a hydraulically operated switching valve. For this purpose, the switching valve has two active surfaces: the delivery pressure of the charge pump acts directly on the first active surface in the closing direction and, after overcoming a non-return valve on the part of the follow-up connection of the master cylinder, in the opening direction on the second active surface. As a result, in the case of active braking, the pressure acting in the closing direction is always greater than the pressure acting in the opening direction and reduced by the admission pressure of the check valve, as long as the isolating valve in the brake line remains closed. When an active braking is ended, the isolating valve is opened so that the brake pressure propagates through the unactuated master cylinder to the switching valve and opens it. An electronic control logic and electrical lines to the switching valve are therefore not required. Such an arrangement of the charge pump above the master cylinder is not limited to brake systems in which precharging is required in both brake circuits, but can also be used for brake systems in which only the return pump of a brake circuit needs to be precharged .
Beim Druckaufbau aus Null heraus ergänzen sich die besonde¬ ren Eigenschaften der Pumpen in idealer Weise: Die Rückför¬ derpumpe ist optimiert für die Erzielung hoher Förderdrücke und kann daher nur vergleichsweise wenig Volumenstrom lie¬ fern. Die Ladepumpe fördert bei niedrigen Drücken einen maxi¬ malen Volumenstrom. Dies ist besonders wichtig bei der Ein¬ leitung eines automatischen Bremsvorgangs, wenn zunächst die Lüftspiele der betreffenden Radbremsen überwunden werden müs¬ sen. Das gilt sowohl für selbstansaugende als auch für nicht- selbstansaugende Rückförderpumpen.When the pressure builds up from zero, the special properties of the pumps complement each other in an ideal manner: the return pump is optimized for achieving high delivery pressures and can therefore only deliver a comparatively small volume flow. The charge pump delivers a maximum volume flow at low pressures. This is particularly important when initiating an automatic braking process if the air clearances of the wheel brakes in question must first be overcome. This applies to both self-priming and non-self-priming return pumps.
Wenn die Rückförderpumpen selbstansaugend ausgelegt sind, und keine Vorladung erfolgt, so dauert der Druckaufbau im unteren Druckbereich wegen der relativ geringen Volumenförderung die¬ ser Hochdruckpumpen erheblich länger. Ein weiteres Problem bei selbst ansaugenden Pumpen tritt auf, wenn das Druckmittel aufgrund niedriger Temperaturen eine besonders hohe Viskosi¬ tät aufweist, so daß durch den Hauptzylinder hindurch ein hoher Strömungswiderstand zu überwinden ist, für dessen Über¬ windung lediglich der auf dem Flüssigkeitsspiegel des Vor¬ ratsbehälters lastende Atmosphärendruck zur Verfügung steht. Eine nähere Erläuterung des Erfindunsgedankens erfolgt nun anhand der Beschreibung von Zeichnungen in zwei Figuren. Dazu zeigtIf the return pumps are designed to be self-priming and there is no precharging, the pressure build-up in the lower pressure range takes considerably longer because of the relatively low volume delivery of these high-pressure pumps. Another problem with self-priming pumps arises when the pressure medium has a particularly high viscosity due to low temperatures, so that a high flow resistance has to be overcome through the master cylinder, for overcoming it only that on the liquid level of the fluid available atmospheric pressure is available. A more detailed explanation of the idea of the invention will now be given with reference to the description of drawings in two figures. This shows
Fig. 1 eine erfindungsgemäße Bremsanlage mit einem hy¬ draulisch betätigten Schaltventil, wobei nur der Nachlaufraum des ersten Bremskreises vorgeladen wird,1 shows a brake system according to the invention with a hydraulically actuated switching valve, only the trailing space of the first brake circuit being precharged,
Fig. 2 eine konstruktive Lösung für ein hydraulisch betätigtes Schaltventil nach Fig. 1.2 shows a constructive solution for a hydraulically operated switching valve according to FIG. 1.
Die Bremsanlage nach Fig. 1 weist zwei Bremskreise I und II auf, die unterhalb des Hauptzylinders 1 identisch aufgebaut sind. Die folgende Beschreibung des Bremskreises I gilt somit analog für den Bremskreis II. Die Bremsleitung 3 verläuft vom Hauptzylinder 1 her über ein elektromagnetisch betätigtes, stromlos geöffnetes Trennventil 4 und teilt sich in zwei Bremszweige 5 und 6. Der Bremszweig 5 führt über das elektro¬ magnetisch betätigte, stromlos geöffnete Einlaßventil 7 zur Radbremse 8, während der Bremszweig 6 über ein ebenfalls stromlos geöffnetes, elektromagnetisch betätigtes Einlaßven¬ til 9 zur Radbremse 10 führt. Von beiden Radbremsen 8 und 10 führt je eine Rücklaufleitung 12 bzw. 14 zu einem Nieder¬ druckspeicher 15. Die Rücklaufleitungen 12 und 14 sind je¬ weils mit einem Auslaßventil 11 bzw. 13 versehen, welche als elektromagnetisch betätigte, stromlos geschlossene 2/2-Wege- ventile gestaltet sind. Der Niederdruckspeicher 15 ist über eine Saugleitung 16, welche später als die zweite Saugleitung bezeichnet wird, mit der Saugseite einer Rückförderpumpe 17 verbunden. Die erste Saugleitung 18 der Rückförderpumpe 17 steht mit der Bremsleitung 3 zwischen Hauptzylinder 1 und Trennventil 4 in Verbindung. Die erste Saugleitung ist mit einem Umschaltventil 19 versehen, welches ein elektromagne¬ tisch betätigtes, stromlos geschlossenes 2/2-Wegeventil ist. Die Rückförderpumpe 17 ist mit ihrer Druckseite über eine Druckleitung 20 an die Bremsleitung 3 zwischen dem Trennven¬ til 4 einerseits und den Einlaßventilen 7 und 9 andererseits angeschlossen.1 has two brake circuits I and II, which are constructed identically below the master cylinder 1. The following description of the brake circuit I thus applies analogously to the brake circuit II. The brake line 3 runs from the master cylinder 1 via an electromagnetically actuated, normally open isolating valve 4 and is divided into two brake branches 5 and 6. The brake branch 5 leads via the electromagnetic actuated, normally open inlet valve 7 to the wheel brake 8, while the brake branch 6 leads via a likewise normally open, electromagnetically operated inlet valve 9 to the wheel brake 10. A return line 12 or 14 leads from each of the two wheel brakes 8 and 10 to a low-pressure accumulator 15. The return lines 12 and 14 are each provided with an outlet valve 11 and 13, respectively, which are electromagnetically operated, normally closed 2/2 Directional valves are designed. The low-pressure accumulator 15 is connected to the suction side of a return pump 17 via a suction line 16, which will be referred to later as the second suction line connected. The first suction line 18 of the return pump 17 is connected to the brake line 3 between the master cylinder 1 and the isolation valve 4. The first suction line is provided with a changeover valve 19, which is an electromagnetically actuated, normally closed 2/2-way valve. The return pump 17 is connected with its pressure side via a pressure line 20 to the brake line 3 between the separating valve 4 on the one hand and the inlet valves 7 and 9 on the other hand.
Die Rückförderpumpe 17 ist zwar selbstansaugend ausgelegt, besitzt jedoch oberhalb des Hauptzylinders 1 eine Vorladeein¬ richtung. Wenn der Hauptzylinder 1 durch das Bremspedal 21 betätigt wird, ist die Verbindung zwischen dem Vorratsbehäl¬ ter 22 und den Radbremsen durch die Druckkammern des Haupt¬ zylinders 1 unterbrochen. In solchen Fällen steht bei betä¬ tigtem Umschaltventil 19 der Hauptzylinderdruck an der Saug¬ seite der Rückförderpumpe zur Verfügung, so daß eine Vorla¬ dung nicht erforderlich ist. Bei unbetätigtem Bremspedal 21 ist die Verbindung zwischen Vorratsbehälter 22 und Bremslei¬ tung 3 durch den Hauptzylinder 1 hindurch geöffnet. Der Hauptzylinder 1 besitzt zwei Behälteranschlüsse 23 und 24, die zwei Hauptzylinderanschlüssen 25 und 26 des Vorratsbehäl¬ ters zugeordnet sind. Zwischen dem Hauptzylinderanschluß 25 und dem Nachlaufanschluß 23, welche beide zum Brems.kreis I gehören, ist ein Schaltventil 27 eingefügt, ein drucklos ge¬ öffnetes, hydraulisch betätigtes 2/2-Wegeventil. Die Verbin¬ dungsleitung zwischen dem Schaltventil 27 und dem Nachlauf- anschluß 23 ist über ein Rückschlagventil 31, welches einen Vordruck von ca. 1 bar aufweist, mit der Druckseite einer Ladepumpe 28 verbunden. Die Saugseite der Ladepumpe 28 ist an den Vorratsbehälter 22 angeschlossen. Durch diese Anordnung sind die Ladepumpe 28 und das Schaltventil 27 parallel¬ geschaltet. Vom Förderdruck der Ladepumpe 28 wird das Schalt¬ ventil 27 in Schließrichtung beaufschlagt, während der Druck am Nachlaufanschluß 23 in Öffnungsrichtung des Schaltventils 27 wirkt. Durch den Vordruck des Rückschlagventils 31 ist bei einer Aktivbremsung mit geschlossenem Trennventil 4, welches den Bremsdruck in den Radbremsen 8 und 10 vom Hauptzylinder 1 fernhält, der Druck am Nachlaufanschluß23 immer kleiner al der an der Druckseite der Ladepumpe 28, so daß das Schaltven¬ til in solchen Fällen geschlossen wird. Zusätzlich ist die Wirkfläche in Öffnungsrichtung kleiner gewählt als die in Schließrichtung, wie später anhand von Fig. 2 erläutert wird.The return pump 17 is designed to be self-priming, but has a pre-charging device above the master cylinder 1. When the master cylinder 1 is actuated by the brake pedal 21, the connection between the reservoir 22 and the wheel brakes is interrupted by the pressure chambers of the master cylinder 1. In such cases, the master cylinder pressure on the suction side of the return pump is available when the changeover valve 19 is actuated, so that preloading is not necessary. When the brake pedal 21 is not actuated, the connection between the reservoir 22 and the brake line 3 is opened through the master cylinder 1. The master cylinder 1 has two container connections 23 and 24, which are assigned to two master cylinder connections 25 and 26 of the storage container. Between the master cylinder connection 25 and the follow-up connection 23, both of which belong to the brake circuit I, a switching valve 27 is inserted, a pressure-free, hydraulically operated 2/2-way valve. The connecting line between the switching valve 27 and the follow-up connection 23 is connected to the pressure side of a charge pump 28 via a check valve 31, which has a pre-pressure of approximately 1 bar. The suction side of the charge pump 28 is on the reservoir 22 connected. This arrangement means that the charge pump 28 and the switching valve 27 are connected in parallel. The switching valve 27 is acted upon by the delivery pressure of the charge pump 28 in the closing direction, while the pressure at the follow-up connection 23 acts in the opening direction of the switching valve 27. Due to the upstream pressure of the check valve 31, the pressure at the follow-up connection 23 is always lower than that on the pressure side of the charge pump 28 during active braking with the isolating valve 4 closed, which keeps the brake pressure in the wheel brakes 8 and 10, so that the switching valve is closed in such cases. In addition, the effective area in the opening direction is chosen to be smaller than that in the closing direction, as will be explained later with reference to FIG. 2.
Auf diese Weise gelangt der Förderdruck der Ladepumpe 28 durch den Hauptzylinder 1, die Bremsleitung 3 und die erste Saugleitung 18 direkt zur Saugseite der Rückförderpumpe 17. Dem Trennventil 4 ist auf bekannte Weise ein Rückschlagventil 29 parallel geschaltet, durch welches der Vorladedruck direkt in die Radbremsen 8 und 10 gelangt, auch wenn das Trennventil zum Zwecke einer automatischen Bremsung geschlossen ist. Da¬ durch kann das Lüftspiel der Bremsen schnell überwunden wer¬ den. Sobald die Bremsen angelegt sind, steigt der Druck in den Radbremsen auf den Vorladedruck. Ein weiterer Druckaufbau kann dann nur mit Hilfe der Rückförderpumpe erfolgen.In this way, the delivery pressure of the charge pump 28 passes through the master cylinder 1, the brake line 3 and the first suction line 18 directly to the suction side of the return pump 17. The check valve 4 is connected in a known manner in parallel with a check valve 29, through which the precharge pressure directly into the wheel brakes 8 and 10 arrives, even if the isolating valve is closed for the purpose of automatic braking. As a result, the air play of the brakes can be quickly overcome. As soon as the brakes are applied, the pressure in the wheel brakes increases to the precharge pressure. A further pressure build-up can then only take place with the help of the return pump.
Parallel zum Schaltventil 27 ist ein Druckbegrenzungsventil 30 angeordnet, welches einen Öffnungsdruck von etwa 10 bar aufweist, bei welchem die Druckseite der Ladepumpe 28 mit dem Vorratsbehälter 22 verbunden wird. Wahlweise kann dieses Druckbegrenzungsventil 30 auch durch eines parallel zur Lade¬ pumpe ersetzt werden. Die dargestellte Bremsanlage wird über den Nachlaufraum des ersten Bremskreises vorgeladen. Durch das Einströmen von Druckmittel wird der erste Bremskreis I befüllt, aber auch der Zwischenkolben des HauptZylinders 1 verschoben. So wird auch der zweite Bremskreis II mit dem Ladedruck beaufschlagt.A pressure limiting valve 30 is arranged parallel to the switching valve 27 and has an opening pressure of approximately 10 bar, at which the pressure side of the charge pump 28 is connected to the reservoir 22. Optionally, this pressure limiting valve 30 can also be replaced by one parallel to the charge pump. The brake system shown is preloaded via the overrun space of the first brake circuit. The inflow of pressure medium fills the first brake circuit I, but also displaces the intermediate piston of the master cylinder 1. In this way, the second brake circuit II is also charged with the boost pressure.
Fig. 2a zeigt eine konstruktive Lösung für ein hydraulisch betätigbares Schaltventil 27 gemäß Fig. 1.FIG. 2a shows a constructive solution for a hydraulically actuated switching valve 27 according to FIG. 1.
Fig. 2b stellt lediglich vergrößert das Ersatzschaltbild für ein solches Schaltventil 27 dar.2b only shows the equivalent circuit diagram for such a switching valve 27 on an enlarged scale.
Die Anordnung nach Fig. 2a weist in einem Gehäuse 40 zwei parallel verlaufende Gehäusebohrungen 41 und 42 auf. In der engeren Bohrung 41 ist das Druckbegrenzungsventil 30 unterge¬ bracht, welches einen Vordruck von etwa lObar aufweist, wäh¬ rend in die Gehäusebohrung 42 größeren Durchmessers das Schaltventil 27 mit integriertem Rückschlagventil 31 einge¬ baut ist. Ein senkrecht zu den beiden Gehäusebohrungen 41 und 42 verlaufende Vebrindungsbohrung 43 verbindet die beiden Eingänge des Rückschlagventils 31 und des Druckbegrenzungs¬ ventils 30 mit der Druckseite der Ladepumpe 28.The arrangement according to FIG. 2a has two parallel housing bores 41 and 42 in a housing 40. The pressure limiting valve 30 is accommodated in the narrower bore 41, which has a pre-pressure of approximately 10 bar, while the switching valve 27 with an integrated check valve 31 is built into the housing bore 42 of larger diameter. A vertical bore 43 running perpendicular to the two housing bores 41 and 42 connects the two inlets of the check valve 31 and the pressure limiting valve 30 to the pressure side of the charge pump 28.
Das Schaltventil 27 weist einen Kolben 44 auf, dessen eine Stirnfläche 45 dem Förderdruck der Ladepumpe 28 ausgesetzt ist. Die andere Stirnseite des Kolbens 45 weist eine Stufe 46, welche von einer Druckfeder 47 zur Druckseite der Lade¬ pumpe 28 hin vorgespannt ist. Ein Fortsatz 48 kleineren Durchmessers trägt als Ventilschließglied einen Dichtring 49, welcher mit einem als konische Verjüngung der Gehäusebohrung 42 ausgeführten Ventilsitz 50 zusammenwirkt. Das Ende des Fortsatzes 48 ragt in einen engeren Abschnitt 51 der Bohrung 42 hinein und trägt an seinem Umfang Einkerbungen 52, welche auch bei axialer Führung des Fortsatzes 48 einen Volumenstrom an diesem Fortsatz entlang erlaubt.The switching valve 27 has a piston 44, one end face 45 of which is exposed to the delivery pressure of the charge pump 28. The other end of the piston 45 has a step 46, which is biased by a compression spring 47 to the pressure side of the loading pump 28. An extension 48 of smaller diameter carries a sealing ring 49 as a valve closing member, which cooperates with a valve seat 50 designed as a conical taper of the housing bore 42. The end of the extension 48 projects into a narrower section 51 of the bore 42 and has notches 52 on its circumference, which even with axial guidance of the extension 48, a volume flow along this extension is permitted.
Der Kolben 44 ist axial durchbohrt und nimmt in seinem Inne¬ ren zentral das Rückschlagventil 31 auf, welches von der Druckseite der Ladepumpe 28 her einen Druckmittelstrom er¬ laubt.The piston 44 is axially pierced and accommodates the check valve 31 centrally in its interior, which allows a pressure medium flow from the pressure side of the charge pump 28.
Am Kolbenende des Fortsatzes 48 ist ein Druckmittelauslaß 53 angelegt, welcher mit dem Nachlaufaufanschluß 23 verbunden ist. Seitlich, zwischen der Stufe 46 und dem Ventilsitz 50 verläuft eine weitere Verbindungsbohrung von der Gehäuseboh¬ rung 42 am Ausgang des Druckbegrenzungsventils 30 entlang zum Behälteranschluß 25 des Vorratsbehälters 22. Die Gehäuseboh¬ rungen 41 und 42 sind in der Darstellung nach rechts zur At¬ mosphäre hin verschlossen. Hierzu ist in die Gehäusebohrung 41 eine elastische Hülse 54 eingefügt, welche mittels einer eingepreßten Kugel 55 im Gehäuse 40 dichtend gehalten wird. Die Gehäusebohrung 42 ist mittels eines Deckels 56, welcher mit dem Gehäuse 40 druckdicht verstemmt ist, verschlossen. Der Deckel 56 besitzt axiale Fortsätze, die einen gehäuse¬ festen Anschlag für den Kolben 44 bilden.At the piston end of the extension 48, a pressure medium outlet 53 is created, which is connected to the wake up port 23. To the side, between the step 46 and the valve seat 50, there is a further connecting bore from the housing bore 42 at the outlet of the pressure relief valve 30 along to the container connection 25 of the storage container 22. The housing bores 41 and 42 are shown to the right in relation to the atmosphere locked up. For this purpose, an elastic sleeve 54 is inserted into the housing bore 41, which is held sealingly in the housing 40 by means of a pressed-in ball 55. The housing bore 42 is closed by means of a cover 56 which is caulked to the housing 40 in a pressure-tight manner. The cover 56 has axial extensions which form a stop for the piston 44 which is fixed to the housing.
Die Anordnung gemäß Fig. 2a funktioniert folgendermaßen: Bei einer Aktivbremung wird die Ladepumpe 28 eingeschaltet. Der Förderdruck verschiebt den Kolben 44 nach links, bis sich der Dichtring 49 an den Ventilsitz 50 anlegt und das Schalt¬ ventil 27 schließt. Ab einem bar Überdruck von Seiten der Ladepumpe 28 fließt das Druckmittel über das Rückschlagventil 31 zum Nachlaufanschluß 23 des Hauptzylinders. Wird innerhalb der Bremsanlage nicht das volle Fördervolumen der Ladepumpe aufgenommen, so fließt dieses über das Druckbegrezungsventil 30 ab 10 bar Überdruck in den Vorratsebheälter 22 ab. Am Ende einer Aktivbremsung fördert die Rückförderpumpe 17 das Druck¬ mittelvolumen des Bremskreises I in den Hauptzylinder 1 zu¬ rück. Da die Ladepumpe 28 mittlerweise abgeschaltet worden ist, liegt in der Verbindungsleitung 43, welche den Kolben 44 in Schließrichtung des Schaltventils 25 beaufschlagt, druck¬ los. Das von der Rückförderpumpe 17 über den Hauptzylinder 1 zum Nachlaufanschluß 23 zurückgeförderte Druckmittelvolumen kann jetzt direkt in den Vorratsbehälter 22 zurückfließen. Das an der Druckseite der Ladepumpe eingeschlossene Volumen kann durch die Ladepumpe 28 in den Vorratsbehälter 22 abflie¬ ßen. Es kann aber auch ein zusätzliches Mittel zur Druckenla- stung der Verbindungsleitung 43 vorgesehen werden. Nach Been¬ digung der Aktivbremsung wirkt einerseits die Druckfeder 47 öffnend auf das Schaltbventil 27 ein, andererseits auch der von der Rückförderpumpe 17 am Nachlaufanschluß 23 erzeugte Druck.The arrangement according to FIG. 2a works as follows: the charge pump 28 is switched on during active braking. The delivery pressure moves the piston 44 to the left until the sealing ring 49 comes into contact with the valve seat 50 and the switching valve 27 closes. From a bar overpressure on the part of the charge pump 28, the pressure medium flows via the check valve 31 to the follow-up connection 23 of the master cylinder. If the full delivery volume of the charge pump is not within the brake system recorded, this flows through the pressure regression valve 30 from 10 bar overpressure into the storage container 22. At the end of active braking, the return pump 17 feeds the pressure medium volume of the brake circuit I back into the master cylinder 1. Since the charge pump 28 has meanwhile been switched off, there is no pressure in the connecting line 43 which acts on the piston 44 in the closing direction of the switching valve 25. The pressure medium volume returned by the return pump 17 via the master cylinder 1 to the follow-up connection 23 can now flow back directly into the reservoir 22. The volume enclosed on the pressure side of the charge pump can flow through the charge pump 28 into the reservoir 22. However, an additional means for relieving pressure on the connecting line 43 can also be provided. After the end of the active braking, on the one hand the compression spring 47 has an opening effect on the switching valve 27, and on the other hand also the pressure generated by the return pump 17 at the follow-up connection 23.
Auf diese Weise ist sichergestellt, daß bei einer Aktivbrem¬ sung das Schialteventil 27 zuverlässig schließ, aber auch nach Beendigung dieser Aktivbremsung mit Sicherheit wieder öffnet. In this way, it is ensured that the slide valve 27 closes reliably during an active braking operation, but also opens again with certainty even after this active braking operation has ended.

Claims

PatentansprücheClaims
Schlupfgeregelte hydraulische Bremsanlage mit einem pe¬ dalbetätigten Hauptzylinder (1) , der über mindestens eine Bremsleitung (3) mit mindestens einer Radbremse (8,10) in Verbindung steht, mit einem Trennventil (4) in der Bremsleitung, mit einer Rückförderpumpe (17), die über eine Druckleitung (20) an die Bremsleitung (3) zwi¬ schen Trennventil (4) und Radbremse (10) angeschlossen ist und die über eine erste, sperrbare Saugleitung (18) an die Bremsleitung (3) zwischen Hauptzylinder (1) und Trennventil (4) sowie über eine zweite Saugleitung (16) an einen Niederdruckspeicher (15) angeschlossen ist, welcher über eine Rücklaufleitung (12,14) mit der Rad¬ bremse (8,10) verbunden ist, mit einem Einlaßventil (7,9) in der Bremsleitung zwischen dem Anschluß der Druckleitung (20) und der Radbremse (8,10), mit einem Auslaßventil (11,13) in der Rücklaufleitung (12,14), mit einem Vorratsbehälter (22), der oberhalb des Hauptzylin¬ ders (1) angeordnet ist und über mindestens einen Haupt- zylinderanschluß (25,26) mit je einem Nachlaufanschluß (23,24) des Hauptzylinders (1) in Verbindung steht, so¬ wie mit einer Ladepumpe (28), die mit ihrer Saugseite an den Vorratsbehälter (22) angeschlossen ist, dadurch ge¬ kennzeichnet, daß in der Verbindung zwischen Hauptzylin¬ deranschluß (25,26) und zumindest einem Nachlaufanschluß (23,24) ein hydraulisch betätigtes Schaltventil (27) angeordnet ist und eine Ladepumpe (28) über ein Rück schlagventil Druckmittel in diesen den Nachlaufanschluß (23,24) fördert,wobei das Schaltventil eine erste Wirk¬ fläche in Schließrichtung aufweist, welche vom Förder¬ druck der Ladepumpe beaufschlagt ist und eine zweite Wirkfläche in Öffnungsrichtung, die vom Druck am Nach¬ laufanschluß beaufschlagt ist.Slip-controlled hydraulic brake system with a pedal-operated master cylinder (1), which is connected to at least one wheel brake (8, 10) via at least one brake line (3), with a separating valve (4) in the brake line, with a return pump (17) which is connected to the brake line (3) between the isolating valve (4) and the wheel brake (10) via a pressure line (20) and which is connected to the brake line (3) between the master cylinder (1) via a first, lockable suction line (18) and isolating valve (4) and via a second suction line (16) to a low-pressure accumulator (15), which is connected to the wheel brake (8, 10) via a return line (12, 14), with an inlet valve (7, 9) in the brake line between the connection of the pressure line (20) and the wheel brake (8,10), with an outlet valve (11,13) in the return line (12,14), with a reservoir (22), which is above the main cylinder ¬ ders (1) and at least one n master cylinder connection (25, 26) is connected to a follow-up connection (23, 24) of the master cylinder (1), as well as to a charge pump (28), which is connected with its suction side to the reservoir (22), characterized in that in the connection between the main cylinder connection (25, 26) and at least one follow-up connection (23, 24) there is a hydraulically operated switching valve (27) and a charge pump (28) via a rear Impact valve pressure medium in this promotes the follow-up connection (23, 24), the switching valve having a first effective area in the closing direction, which is acted upon by the delivery pressure of the charge pump, and a second effective area in the opening direction, which is acted upon by the pressure at the follow-up connection .
Bremsanlage nach Anspruch 1, dadurch gekennzeichnet, daß die zweite Wirkfläche kleiner ist als die erste.Brake system according to claim 1, characterized in that the second effective area is smaller than the first.
Bremsanlage nach Anspruch 2, dadurch gekennzeichnet, daß das Schaltventil (27) in einem Gehäuse einen an seinem Umfang abgedichteten Kolben (44) aufweist, der mit einer Stirnseite (45) dem Förderdruck der Ladepumpe (28) aus¬ gesetzt ist und an seiner anderen Stirnseite ein Ventil¬ schließglied (49) trägt, welches mit einem gehäusefe¬ sten, ringförmigen Ventilsitz (50) zusammenwirkt und die Berbindung zwischen Nachlaufanschluß (23) und Hauptzy¬ linderanschluß (25) kontrolliert.Brake system according to claim 2, characterized in that the switching valve (27) in a housing has a piston (44) which is sealed on its circumference and which is exposed to the delivery pressure of the charge pump (28) with one end face (45) and on the other A valve closing member (49) carries at the end face, which cooperates with a housing-shaped, annular valve seat (50) and controls the connection between the follow-up connection (23) and the main cylinder connection (25).
Bremsanlage nach Anspruch 3, dadurch gekennzeichnet, daß innerhalb des Kolbens (44) das Rückschlagventil (31) angeordnet ist, daß der Ausgeng des Rückschlagventils (31) durch das Schließglied (49) hindurch verläuft und daß durch den Ventilsitz (50) eine Bohrung geführt ist, die mit dem Nachlaufanschluß (23) in Verbindung steht. Brake system according to Claim 3, characterized in that the check valve (31) is arranged within the piston (44), that the check valve (31) extends through the closing member (49) and that a bore is passed through the valve seat (50) which is connected to the trailing connection (23).
PCT/EP1997/000285 1996-02-03 1997-01-22 Slip-controlled hydraulic brake system with charge pump WO1997028031A1 (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
JP9527275A JP2000503933A (en) 1996-02-03 1997-01-22 Slip control type hydraulic brake device with filling pump
EP97901582A EP0874748A1 (en) 1996-02-03 1997-01-22 Slip-controlled hydraulic brake system with charge pump

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE19603871.5 1996-02-03
DE1996103871 DE19603871A1 (en) 1996-02-03 1996-02-03 Slip-controlled hydraulic brake system with charge pump

Publications (1)

Publication Number Publication Date
WO1997028031A1 true WO1997028031A1 (en) 1997-08-07

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EP (1) EP0874748A1 (en)
JP (1) JP2000503933A (en)
DE (1) DE19603871A1 (en)
WO (1) WO1997028031A1 (en)

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WO1992017357A1 (en) * 1991-04-04 1992-10-15 Alfred Teves Gmbh Motor vehicle braking system with brake slip and drive slip-dependent control of the braking pressure
DE4128091A1 (en) * 1991-08-24 1993-02-25 Teves Gmbh Alfred BRAKE SYSTEM WITH ANTI-BLOCK PROTECTION AND SLIP CONTROL
DE4232311C1 (en) * 1992-09-26 1994-02-24 Bosch Gmbh Robert Hydraulic vehicle brake system with anti-lock device
DE4329139C1 (en) * 1993-08-30 1994-07-28 Daimler Benz Ag Brake pressure control unit for road vehicle with hydraulic multi-circuit brakes
WO1997002166A1 (en) * 1995-07-05 1997-01-23 Itt Automotive Europe Gmbh Antislip control hydraulic braking system with precharging pump

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1997042067A1 (en) * 1996-05-08 1997-11-13 Robert Bosch Gmbh Hydraulic vehicle brake system
GB2350654A (en) * 1999-06-02 2000-12-06 Rover Group A brake modulation arrangement
US6431662B2 (en) 2000-03-01 2002-08-13 Toyota Jidosha Kabushiki Kaisha Vehicle braking pressure source device wherein fluid communication between pressurizing and back-pressure chambers of master cylinder is controlled based on vehicle running state and/or road surface condition
IT202200007445A1 (en) * 2022-04-14 2023-10-14 Brembo Spa Brake fluid reservoir
WO2023199278A1 (en) * 2022-04-14 2023-10-19 Brembo S.P.A. Brake fluid reservoir

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JP2000503933A (en) 2000-04-04
DE19603871A1 (en) 1997-08-07
EP0874748A1 (en) 1998-11-04

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