EP2250057A1 - Hydraulic system with improved pulsation damping - Google Patents

Hydraulic system with improved pulsation damping

Info

Publication number
EP2250057A1
EP2250057A1 EP09708798A EP09708798A EP2250057A1 EP 2250057 A1 EP2250057 A1 EP 2250057A1 EP 09708798 A EP09708798 A EP 09708798A EP 09708798 A EP09708798 A EP 09708798A EP 2250057 A1 EP2250057 A1 EP 2250057A1
Authority
EP
European Patent Office
Prior art keywords
damping
hydraulic
valve
pressure
pump
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP09708798A
Other languages
German (de)
French (fr)
Inventor
Ronald Kley
Stefan Schmitt
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Continental Teves AG and Co OHG
Original Assignee
Continental Teves AG and 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 and Co OHG filed Critical Continental Teves AG and Co OHG
Publication of EP2250057A1 publication Critical patent/EP2250057A1/en
Withdrawn legal-status Critical Current

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
    • B60T8/00—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force
    • B60T8/32—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration
    • B60T8/34—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
    • B60T8/42—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 having expanding chambers for controlling pressure, i.e. closed systems
    • 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
    • B60T8/40—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 comprising an additional fluid circuit including fluid pressurising means for modifying the pressure of the braking fluid, e.g. including wheel driven pumps for detecting a speed condition, or pumps which are controlled by means independent of the braking system
    • B60T8/4068—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 comprising an additional fluid circuit including fluid pressurising means for modifying the pressure of the braking fluid, e.g. including wheel driven pumps for detecting a speed condition, or pumps which are controlled by means independent of the braking system the additional fluid circuit comprising means for attenuating pressure pulsations
    • 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
    • B60T8/40—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 comprising an additional fluid circuit including fluid pressurising means for modifying the pressure of the braking fluid, e.g. including wheel driven pumps for detecting a speed condition, or pumps which are controlled by means independent of the braking system

Definitions

  • the invention relates to a hydraulic unit with improved pulsation damping comprising a receiving body with electrohydraulic valves, with at least one hydraulic pump, and with channels for connecting the pump with at least one hydraulic consumer, wherein due to pressure medium delivery by the pump and / or as a result of pressure fluid removal by the consumer a pulsation situation is given, and that at least one damping unit is provided, which has a plurality of Pulsationsdämpfungsstoff, in particular damping chamber, Elasto emotions, aperture.
  • Such a hydraulic unit for use in a motor vehicle brake system is known for example from DE 10 2005 028 562 Al, and characterized in that the Pulsationsdämpfungsffen are designed differently. Although the task is solved in principle by this measure, the pulsation behavior is still capable of improvement.
  • the noise insulation in the interior of modern motor vehicles is optimized in such a way that, for example, haptic feedback - such as in particular brake pedal vibration - emerges particularly negatively, and is objected to.
  • ABS control interventions often take place at a driver-side brake pressure of, for example, 100 bar and more and require a return promotion in the direction of actuation unit THZ.
  • Other interventions for example the hydraulic actuation for parking brake functions, requires an accelerated filling of brake calipers with a comparatively high volume intake, that is to say a high volume flow at a comparatively low pressure level.
  • the design of the motor vehicle brake system with respect to the volume flow rate is basically such that the delivery capacity of the pump after the maximum volume flow promotion required to cover particularly safety-critical control actions, such.
  • ESP driving stability control intervention
  • ARP anti-rollover protection
  • These interventions are based in principle on an autonomous system intervention, without being able to resort to any support or prefilling by the driver.
  • These boundary conditions require a comparatively large-sized displacement volume (large piston diameter, large displacement stroke). This dimensioning has a negative effect on a pulsation evaluation and in the noise behavior, in particular if comparatively small delivery volumes are in demand.
  • multi-circuit pumps mainly have a jointly bundled drive train, so that all pistons are constantly taken in pump operation, even if no flow is requested in any of the pump circuits.
  • a delivery volume is withdrawn by the consumer in only one of two pump circuits, and if no delivery volume (zero delivery) is withdrawn from the other pump circuit, a negative pressure formation (cavitation) due to "suction-throttled" operation occurs in the pump circuit with zero delivery at least in one part of the intake path Because the suction path of the pump is constantly closed, the negative pressure can release dissolved gas components, which leads to undesirable compressibility in the brake system.
  • the invention is based on the object to further develop generic hydraulic units such that a uniform and cost-effective problem solution is offered for the very differently stored problems, and a comfort reduction due to pulsation effect is not given.
  • the object is solved by the features of independent claim 1.
  • the invention is associated with the particular advantage that a situational adapted, automatic adaptation of the physical properties and effects of the damping unit to the respective existing pulsation characteristic is made possible.
  • an automatic adaptation of the damping unit takes place to an impressed pulsation characteristic, no fixed operating point of the damping unit is defined.
  • the pulsation reduction is improved because the effect of the attenuation measure is adaptive to an extended one Operating range is extended. This allows an increased range of action covering both high pressure applications at low flow rates and high flow volumes at low pressure.
  • FIG. 5 shows parts of a hydraulic unit with a damping unit enlarged, in section, according to a first embodiment
  • Fig. 6 pressure-time curves taken at a damping unit and at a consumer in a hydraulic unit according to the invention
  • Fig. 7 Pressure-time curves taken at a damping chamber and at a consumer in a conventional hydraulic unit.
  • a hydraulic unit HCU with a receiving body 1 for electro-hydraulic valves 2,3 and a pump 4, in particular reciprocating pump, which is arranged between an actuating unit THZ (master cylinder with container) and wheel brakes B (consumer).
  • the hydraulic unit HCU allows in particular a pressure modulation.
  • the pump 4 is driven by an electric motor.
  • a variable speed motor M is used, so that the delivery rate is adjustable.
  • a suction path of the pump 4 comprises a suction valve 5, which is either differential pressure controlled or electromagnetically controlled.
  • the suction path with the aid of a non-illustrated, normally closed, switching valve is designed switchable so that either from the operating unit THZ, or from a low-pressure accumulator, not shown - which is in principle connected to an outlet of a wheel B - can be sucked.
  • the electro-hydraulic valve 2 is designed as a normally open disconnect valve, so that in the closed state switching a driver-independent operation is enabled, and in the open state, a conventional brake operation can take place.
  • the still visible electrohydraulic valve 3 is designed in principle as normally open inlet valve for the wheel B.
  • a pressure valve 6 and an adaptively adjustable damping unit 7 is arranged with a plurality of damping means.
  • a damping chamber 8 and a, the damping chamber 8 downstream, aperture unit provided.
  • the aperture unit includes a fixed aperture 9 and a switchable aperture 10.
  • the aperture 9 has a large, comparatively wide aperture with reduced glare, while the aperture 10 is a small, relatively narrow aperture having high glare.
  • the adaptive adaptation of the damping unit 7 takes place by switching.
  • This switching function is shown symbolically in the embodiment by a differential pressure controlled check valve 11, which is arranged parallel to the aperture 10 in a bypass 12, and closes the bypass 12 in the home position.
  • Pulsation characteristic customizable, damping unit 7 allows automatic adjustment of the damping unit 7 to the respective pulsation conditions.
  • at least two different switching states are to be distinguished from each other.
  • the valve body 13 lifts from its valve seat 14, so that the pulsating volume flow passes directly to the damping chamber 8 directly through the aperture 9 with large aperture.
  • the biasing force on the valve body 13 is predetermined so that, for example, comparatively high pulsation effect triggers the switching process.
  • the damping cascade formed comprises only the effect of the damping chamber 8 in combination with the effect of the aperture 9 with a large passage opening.
  • Damping unit 7 is that it can be easily integrated with the necessary components into a modular designed large series, which allows a variably designed, adaptive pulsation damping based on different, modular equipped embodiments, without significant modification effort, for example, to the electro-hydraulic valves 2,3, to cause the receiving body 1, an electronic control or other components. Because components of the damping unit 7 can be easily added as needed, in the sense of a kit or omitted.
  • the apertures of the two apertures 9, 10 are preferably dimensioned differently large. For example, these generally have a comparatively small diameter of a few tenths of a millimeter.
  • a preferred gradation of the apertures is for example in a range of about 0.2 mm to 0.5 mm (each up to +/- 0.25 mm deviation). Consequently, the aperture is the Aperture 10 dimensioned compared to the aperture of the aperture 9 only about half as large.
  • the physical effects of the damping unit 7 are basically as follows.
  • the hydraulic pressure medium DM although incompressible in principle, slightly elastic at least in the high pressure area (elasticity of the pressure medium).
  • Another additional elasticity E is symbolically given by separate damping means.
  • the diaphragms 9, 10 with their respective diaphragm opening are dimensioned with regard to certain pulsation characteristics such that a certain dynamic pressure can be built up in the damping chamber 8, so that the damping chamber 8 provides elasticity due to the pressure fluid volume stored therein.
  • FIG. 6 The mechanism of a particularly successful extinction or reduction can be seen particularly well from FIG. 6.
  • Background is a cascaded, turn-off dimming of a damping chamber 8 with about 100 mm pressure medium volume.
  • the right-hand diagram in FIG. 6 illustrates a strongly smoothed wheel pressure curve p_VR with a respectively considerable increase in the damping chamber pressure p D in relation to the wheel pressure p VR. This suggests a greatly inflated dynamic pressure, which causes the explained phase shift. As a result, the wheel pressure waveform shows substantially no nonuniformity.
  • a damping system according to Fig. 7 is not based on the invention, but only on a cascaded blend of an elastomeric membrane 15 with about 60 Shore hardness (without use of a damping chamber).
  • the right-hand diagram of FIG. 7 shows a non-uniform staircase-shaped wheel pressure profile p VR, wherein the damping chamber pressure p_D drops in places down to the wheel pressure p VR. This documents a - largely unsatisfactory - damping function of the damping unit used.
  • FIG. 4 illustrates the respectively available elasticity E.
  • a kink K in the volume characteristic graphically illustrates that the elasticity and thus the glare is reduced by the described switching operation under high system pressure, so that the volume absorption in the damping chamber 8 is also reduced.
  • the elasticity (slope of the characteristic curve) in a first section is for example about 6 mm / bar and in a second section about 0.5 mm 3 / bar.
  • the bypass 12 is provided with the check valve 11, which limits the maximum generated dynamic pressure.
  • the opening pressure from the check valve 11 can preferably be selected the lower, the more elastic the tuning of the overall system (tuning of the damping chamber 8, diaphragms 9, 10 and elasticity / pressure medium) is formed.
  • an elastic membrane 15 is arranged in the damping chamber 8, which separates the fluid-filled damping chamber 8 from a pneumatic chamber 16.
  • the pneumatic space 16 may, according to one embodiment, be separated from the ambient atmosphere U by a closure 17. Alternatively, a pressure equalization between the pneumatic chamber 16 and the ambient atmosphere U.
  • the two apertures 9,10 and the check valve 11 are formed as a separate handle assembly, and inserted starting from a receiving bore of the damping chamber 8 in a stepped bore 18 from the pressure channel.
  • the valve seat 14 has a specifically provided notch 19, whose cross section corresponds to the diaphragm opening.
  • a diaphragm 9 may be provided in the middle of a base 21 of a housing 22 relative to the valve seat 14 (FIG. 1).
  • a channel or slot shaped aperture (notch 19)
  • the expanded aperture is created by lifting valve body 13 away from valve seat 14 (Fig. 5).
  • This design is characterized by the fact that the cross section of the aperture 9 can be set even variable depending on the applied pressure difference, while according to FIG. 2, a fixed value is always defined. In other words, it is quite possible to make either the diaphragm 9 or the diaphragm 10 variable.
  • the switching logic can be implemented differently by, for example, as in Fig. 1, the aperture 10 is turned off, because a check valve 11 opens the bypass 12, or the aperture 10 is opened in the sense of a switching diaphragm pressure dependent (Fig. 2).
  • the damping unit 7 may have self-cleaning properties by flushing fine orifices during operation during phases of higher pressures / drive speeds. Should dirt particles clog any apertures completely during low pressure phases, the pressure in the damping chamber 8 will automatically increase and the check valve 11 will open. Thus, an overload of the pump 4 is prevented, the safe function is further ensured, and the fine aperture 9 is cleaned during phases of high pressure (self-healing behavior).
  • FIG. 5 shows a further, modified embodiment of the invention.
  • a plurality of metallic elastomer bodies 23 are in the damping chamber 8 added.
  • the Elasto stresses 23 may be designed, for example, as a hermetically sealed, compressible barometer.
  • the Elasto stresses 23 serve to influence and produce the desired elasticity E. Another advantage is that relatively little volume of brake fluid must be filled into the receiving body by the volume absorption, and that at the same time a defined elasticity is provided.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Transportation (AREA)
  • Mechanical Engineering (AREA)
  • Valves And Accessory Devices For Braking Systems (AREA)
  • Regulating Braking Force (AREA)
  • Fluid-Pressure Circuits (AREA)

Abstract

The invention relates to a hydraulic system HCU comprising a receiving body (1) with electrohydraulic valves (2, 3) with at least one hydraulic pump (4), and with channels for connecting the pump (4) to at least one hydraulic load, wherein as a result of the delivery of a pressure medium by the pump (4) and/or as a result of pressure medium being withdrawn by the load a pulsation situation arises, and at least one damping unit (7) is provided, which comprises a plurality of pulsation damping means such as, in particular, a damping chamber (8), and orifice (9, 10). The object of the invention is to refine generic hydraulic systems such that a uniform and cost-effective solution is provided for very different operating situations and a decrease in comfort as a result of the pulsation effect is prevented. The object is achieved in that the damping unit (7) comprises at least one switching means for adjusting the action of said damping unit (7) to a varied pulsation situation by connecting or disconnecting one or more damping means.

Description

Hydraulikaggregat mit verbesserter PulsationsdämpfungHydraulic unit with improved pulsation damping
Die Erfindung betrifft ein Hydraulikaggregat mit verbesserter Pulsationsdämpfung umfassend einen Aufnahmekörper mit elektrohydraulischen Ventilen, mit wenigstens einer hydraulischen Pumpe, und mit Kanälen zur Verbindung der Pumpe mit wenigstens einem hydraulischen Verbraucher, wobei infolge Druckmittelförderung durch die Pumpe und/oder infolge Druckmittelentnahme durch den Verbraucher eine Pulsationssituation gegeben ist, und dass wenigstens eine Dämpfungseinheit vorgesehen ist, welche mehrere Pulsationsdämpfungsmittel, wie insbesondere Dämpfungskammer, Elastokörper, Blende aufweist.The invention relates to a hydraulic unit with improved pulsation damping comprising a receiving body with electrohydraulic valves, with at least one hydraulic pump, and with channels for connecting the pump with at least one hydraulic consumer, wherein due to pressure medium delivery by the pump and / or as a result of pressure fluid removal by the consumer a pulsation situation is given, and that at least one damping unit is provided, which has a plurality of Pulsationsdämpfungsmittel, in particular damping chamber, Elastokörper, aperture.
Ein derartiges Hydraulikaggregat zum Einsatz in einer Kraftfahrzeugbremsanlage ist beispielsweise aus der DE 10 2005 028 562 Al bekannt, und dadurch gekennzeichnet, dass die Pulsationsdämpfungsmittel unterschiedlich ausgebildet sind. Obwohl durch diese Maßnahme die gestellte Aufgabe prinzipiell gelöst wird, ist das Pulsationsverhalten weiterhin verbesserungsfähig. Beispielsweise ist die Geräuschdämmung im Innenraum moderner Kraftfahrzeuge derart optimiert, dass beispielsweise haptische Rückmeldungen - wie insbesondere Bremspedalvibration - besonders negativ hervortritt, und beanstandet wird.Such a hydraulic unit for use in a motor vehicle brake system is known for example from DE 10 2005 028 562 Al, and characterized in that the Pulsationsdämpfungsmittel are designed differently. Although the task is solved in principle by this measure, the pulsation behavior is still capable of improvement. For example, the noise insulation in the interior of modern motor vehicles is optimized in such a way that, for example, haptic feedback - such as in particular brake pedal vibration - emerges particularly negatively, and is objected to.
Grundsätzlich bekannte Pulsationsdämpfungsmaßnahmen leiden unter dem Nachteil, dass diese nur punktuell zufriedenstellend arbeiten . ABS-Regeleingriffe finden oftmals bei einem fahrerseitig eingesteuerten Bremsdruck von beispielsweise 100 bar und mehr statt und erfordern eine Rückförderung in Richtung Betätigungseinheit THZ. Andere Eingriffe, beispielsweise die hydraulische Betätigung für Parkbremsfunktionen, erfordert eine beschleunigte Befüllung von Bremssätteln mit vergleichsweise hoher Volumenaufnahme, also hohem Volumenstrom bei vergleichsweise geringem Druckniveau.Basically known Pulsationsdämpfungsmaßnahmen suffer from the disadvantage that they work only selectively satisfactory. ABS control interventions often take place at a driver-side brake pressure of, for example, 100 bar and more and require a return promotion in the direction of actuation unit THZ. Other interventions, for example the hydraulic actuation for parking brake functions, requires an accelerated filling of brake calipers with a comparatively high volume intake, that is to say a high volume flow at a comparatively low pressure level.
Andererseits wird eine optimierte Dosierbarkeit bei möglichst hohem NVH-Komfort (Noise-Vibration-Harshness) für Assistenzfunktionen nachgefragt, die folglich vergleichsweise flache Druckanstiegs- und/oder Druckabbaugradienten erfordern, damit möglichst hoher Komfort geboten wird.On the other hand, optimized metering with the highest possible NVH comfort (noise vibration harshness) for assistance functions is demanded, which consequently require comparatively shallow pressure increase and / or pressure reduction gradients, so that the highest possible level of comfort is provided.
Die Auslegung der Kraftfahrzeugbremsanlage in Hinblick auf die Volumenstromförderleistung erfolgt grundsätzlich derart, dass die Förderkapazität der Pumpe nach der maximal erforderlichen Volumenstromförderung zur Abdeckung besonders sicherheitskritischer Regelungseingriffe, wie z. B. Fahrstabilitätsregeleingriffe (ESP) , Anti-Rollover-Protection (ARP) oder ähnliches dimensioniert wird. Diese Eingriffe beruhen prinzipiell auf einem autonomen Systemeingriff, ohne auf irgendwelche Unterstützung oder Vorfüllung durch den Fahrzeugführer zurück greifen zu können. Diese Randbedingungen erfordern ein vergleichsweise groß dimensioniertes Verdrängungsvolumen (großer Kolbendurchmesser, großer Verdrängungshub) . Diese Dimensionierung wirkt sich bei einer Pulsationsbewertung und im Geräuschverhalten negativ aus, insbesondere wenn vergleichsweise kleine Fördervolumina nachgefragt werden. Weiterhin verfügen mehrkreisige Pumpen vorwiegend über einen gemeinsam gebündelten Antriebsstrang, so dass im Pumpenbetrieb ständig alle Kolben mitgenommen werden, selbst wenn in irgendeinem der Pumpenkreise kein Förderstrom angefordert wird.The design of the motor vehicle brake system with respect to the volume flow rate is basically such that the delivery capacity of the pump after the maximum volume flow promotion required to cover particularly safety-critical control actions, such. B. driving stability control intervention (ESP), anti-rollover protection (ARP) or the like dimensioned. These interventions are based in principle on an autonomous system intervention, without being able to resort to any support or prefilling by the driver. These boundary conditions require a comparatively large-sized displacement volume (large piston diameter, large displacement stroke). This dimensioning has a negative effect on a pulsation evaluation and in the noise behavior, in particular if comparatively small delivery volumes are in demand. Furthermore, multi-circuit pumps mainly have a jointly bundled drive train, so that all pistons are constantly taken in pump operation, even if no flow is requested in any of the pump circuits.
Wenn beispielsweise in nur einem von zwei Pumpenkreisen durch den Verbraucher ein Fördervolumen entnommen wird, und wenn dem anderen Pumpenkreis keinerlei Fördervolumen (Nullförderung) entnommen wird, entsteht im Pumpenkreis mit Nullförderung zumindest in einem Teil vom Saugpfad eine Unterdruckbildung (Kavitation) infolge „sauggedrosseltem" Betrieb. Denn der Saugpfad der Pumpe ist fortwährend verschlossen. Durch den Unterdruck können gelöste Gasanteile frei werden, was zu unerwünschten Kompressiblitäten im Bremssystem führt.If, for example, a delivery volume is withdrawn by the consumer in only one of two pump circuits, and if no delivery volume (zero delivery) is withdrawn from the other pump circuit, a negative pressure formation (cavitation) due to "suction-throttled" operation occurs in the pump circuit with zero delivery at least in one part of the intake path Because the suction path of the pump is constantly closed, the negative pressure can release dissolved gas components, which leads to undesirable compressibility in the brake system.
Der Erfindung liegt die Aufgabe zu Grunde, gattungsgemäße Hydraulikaggregate derart weiter zu entwickeln, dass für die sehr unterschiedlich gelagerten Probleme eine einheitliche und kostengünstige Problemlösung angeboten wird, und eine Komfortminderung infolge Pulsationswirkung nicht gegeben ist.The invention is based on the object to further develop generic hydraulic units such that a uniform and cost-effective problem solution is offered for the very differently stored problems, and a comfort reduction due to pulsation effect is not given.
Die Aufgabe wird durch die Merkmale vom unabhängigen Patentanspruch 1 gelöst. Die Erfindung ist mit dem besonderen Vorteil verknüpft, dass eine situativ angepasste, automatische Adaption von den physikalischen Eigenschaften und Wirkungen der Dämpfungseinheit an die jeweils bestehende Pulsationscharakteristik ermöglicht wird. Indem also eine selbsttätige Anpassung der Dämpfungseinheit an eine aufgeprägte Pulsationscharakteristik erfolgt, ist kein fester Arbeitspunkt der Dämpfungseinheit definiert. Als Ergebnis wird die Pulsationsminderung verbessert, weil die Wirkung der Dämpfungsmaßnahme adaptiv auf einen erweiterten Betriebsbereich erstreckt wird. Dadurch wird ein vergrößerter Wirkungsbereich ermöglicht, der sowohl Hochdruckanwendungen bei geringen Fördervolumina, als auch hohe Fördervolumina bei niedrigem Druck abdeckt.The object is solved by the features of independent claim 1. The invention is associated with the particular advantage that a situational adapted, automatic adaptation of the physical properties and effects of the damping unit to the respective existing pulsation characteristic is made possible. Thus, by an automatic adaptation of the damping unit takes place to an impressed pulsation characteristic, no fixed operating point of the damping unit is defined. As a result, the pulsation reduction is improved because the effect of the attenuation measure is adaptive to an extended one Operating range is extended. This allows an increased range of action covering both high pressure applications at low flow rates and high flow volumes at low pressure.
Weitere Einzelheiten der Erfindung gehen aus Unteransprüchen im Zusammenhang mit der Beschreibung anhand der Zeichnung hervor. In der Zeichnung zeigt:Further details of the invention will become apparent from dependent claims in connection with the description with reference to the drawings. In the drawing shows:
Fig. 1: Teilweise ein prinzipieller Schaltplan eines Hydraulikkreises einer Kraftfahrzeugbremsanlage mit schaltbarer Dämpfungseinheit,1: partially a schematic diagram of a hydraulic circuit of a motor vehicle brake system with switchable damping unit,
Fig. 2: schematisch, vergrößert sowie teilweise konstruktive Einzelheiten einer abgewandelten Dämpfungseinheit,2 shows schematically, enlarged and partially constructive details of a modified damping unit,
Fig. 3: schematisierter Schaltplan vergleichbar Fig. 1,3: schematic circuit diagram comparable to FIG. 1,
Fig. 4: schematisierte Kennlinie zur Verdeutlichung der adaptiv angepassten Dämpfungswirkung einer Dämpfungseinheit,4 is a schematic characteristic curve to illustrate the adaptively adjusted damping effect of a damping unit,
Fig. 5: Teile von einem Hydraulikaggregat mit einer Dämpfungseinheit vergrößert, im Schnitt, gemäß einer ersten Ausführungsform,5 shows parts of a hydraulic unit with a damping unit enlarged, in section, according to a first embodiment,
Fig. 6: Druck-Zeit-Verläufe genommen an einer Dämpfungseinheit und an einem Verbraucher bei einem erfindungsgemäßen Hydraulikaggregat, undFig. 6: pressure-time curves taken at a damping unit and at a consumer in a hydraulic unit according to the invention, and
Fig. 7: Druck-Zeit-Verläufe genommen an einer Dämpfungskammer und an einem Verbraucher bei einem konventionellen Hydraulikaggregat . Nachstehend wird im Einzelnen auf die Fig. 1 eingegangen. Diese verdeutlicht schematisch sowie teilweise ein Hydraulikaggregat HCU mit einem Aufnahmekörper 1 für elektrohydraulische Ventile 2,3 und eine Pumpe 4, insbesondere Hubkolbenpumpe, die zwischen einer Betätigungseinheit THZ (Hauptzylinder mit Behälter) und Radbremsen B (Verbraucher) angeordnet ist. Das Hydraulikaggregat HCU ermöglicht insbesondere eine Druckmodulation. Die Pumpe 4 ist elektromotorisch angetrieben. Bevorzugt findet ein drehzahlvariierbarer Motor M Verwendung, so dass die Förderleistung regulierbar ist. Ein Saugpfad der Pumpe 4 umfasst ein Saugventil 5, das entweder differenzdruckgesteuert oder elektromagnetisch gesteuert ist. Weiterhin ist der Saugpfad mit Hilfe von einem nicht dargestellten, stromlos geschlossenen, Umschaltventil derart umschaltbar gestaltet, dass entweder aus der Betätigungseinheit THZ, oder aus einem nicht gezeigten Niederdruckspeicher - welcher grundsätzlich an einen Auslass einer Radbremse B angeschlossen ist - angesaugt werden kann. Weiterhin ist das elektrohydraulische Ventil 2 als stromlos offenes Trennventil ausgelegt, so dass im geschlossenen Schaltzustand eine fahrerunabhängige Betätigung ermöglicht ist, und im offenen Zustand eine konventionelle Bremsbetätigung erfolgen kann. Das weiterhin ersichtliche elektrohydraulische Ventil 3 ist prinzipiell als stromlos offenes Einlassventil für die Radbremse B ausgelegt.Fig. 7: Pressure-time curves taken at a damping chamber and at a consumer in a conventional hydraulic unit. The following will be discussed in detail on the Fig. 1. This illustrates schematically and partially a hydraulic unit HCU with a receiving body 1 for electro-hydraulic valves 2,3 and a pump 4, in particular reciprocating pump, which is arranged between an actuating unit THZ (master cylinder with container) and wheel brakes B (consumer). The hydraulic unit HCU allows in particular a pressure modulation. The pump 4 is driven by an electric motor. Preferably, a variable speed motor M is used, so that the delivery rate is adjustable. A suction path of the pump 4 comprises a suction valve 5, which is either differential pressure controlled or electromagnetically controlled. Furthermore, the suction path with the aid of a non-illustrated, normally closed, switching valve is designed switchable so that either from the operating unit THZ, or from a low-pressure accumulator, not shown - which is in principle connected to an outlet of a wheel B - can be sucked. Furthermore, the electro-hydraulic valve 2 is designed as a normally open disconnect valve, so that in the closed state switching a driver-independent operation is enabled, and in the open state, a conventional brake operation can take place. The still visible electrohydraulic valve 3 is designed in principle as normally open inlet valve for the wheel B.
Die beschriebene Umschaltung im Saugpfad der Pumpe 4 ermöglicht es je nach Schaltzustand, Druckmittel entweder in Richtung Betätigungseinheit THZ oder in Richtung Radbremse B zu fördern. Im Druckpfad der Pumpe 4 ist ein Druckventil 6 und eine adaptiv anpassbare Dämpfungseinheit 7 mit mehreren Dämpfungsmitteln angeordnet. Bei der schematisch verdeutlichten Anordnung ist eine Dämpfungskammer 8 und eine, der Dämpfungskammer 8 nachgeschaltete, Blendeneinheit vorgesehen. Ganz generell umfasst die Blendeneinheit eine fest installierte Blende 9 und eine schaltbare Blende 10. Wie auch sinnbildlich aus Fig. 1 hervorgeht, verfügt die Blende 9 über eine große, vergleichsweise weite Blendenöffnung mit verringerter Blendwirkung, während die Blende 10 eine kleine, vergleichsweise enge Blendenöffnung mit hoher Blendwirkung aufweist. Die adaptive Anpassung der Dämpfungseinheit 7 erfolgt durch Umschaltung. Diese Schaltfunktion ist bei der Ausführungsform sinnbildlich durch ein differenzdruckgesteuertes Rückschlagventil 11 dargestellt, welches parallel zur Blende 10 in einem Bypass 12 angeordnet ist, und den Bypass 12 in Grundstellung verschließt. Durch die beschriebene, adaptiv an die jeweiligeThe described switching in the suction path of the pump 4 makes it possible, depending on the switching state, to convey pressure medium either in the direction of the actuating unit THZ or in the direction of the wheel brake B. In the pressure path of the pump 4, a pressure valve 6 and an adaptively adjustable damping unit 7 is arranged with a plurality of damping means. In the schematically illustrated arrangement, a damping chamber 8 and a, the damping chamber 8 downstream, aperture unit provided. Quite generally, the aperture unit includes a fixed aperture 9 and a switchable aperture 10. As also emblematically apparent from Fig. 1, the aperture 9 has a large, comparatively wide aperture with reduced glare, while the aperture 10 is a small, relatively narrow aperture having high glare. The adaptive adaptation of the damping unit 7 takes place by switching. This switching function is shown symbolically in the embodiment by a differential pressure controlled check valve 11, which is arranged parallel to the aperture 10 in a bypass 12, and closes the bypass 12 in the home position. Through the described, adaptively to the respective
Pulsationscharakteristik anpassbare, Dämpfungseinheit 7 wird eine selbsttätige Anpassung der Dämpfungseinheit 7 an die jeweiligen Pulsationsbedingungen ermöglicht. In diesem Zusammenhang sind zumindest zwei unterschiedliche Schaltzustände voneinander zu unterscheiden.Pulsation characteristic customizable, damping unit 7 allows automatic adjustment of the damping unit 7 to the respective pulsation conditions. In this context, at least two different switching states are to be distinguished from each other.
a) wenn die ausgeübte Druckdifferenz am Rückschlagventil 11 nicht ausreicht, um dieses zu öffnen, ist zunächst stets die vorgeschaltete Blende 10 mit kleiner Blendenöffnung aktiv. Im Anschluss gelangt der Volumenstrom durch die Blende 9 mit großer Blendenöffnung. Für diesen Schaltzustand bewirkt die Dämpfungseinheit 7 eine kaskadierte, mit anderen Worten in Serie geschaltete, Wirkung von Dämpfungskammer 8 sowie der beiden in Serie geschalteten Blenden 9,10 mit unterschiedlich großen Blendenöffnungen. Anschließend verlässt das Druckmittel die Dämpfungseinheit 7 und gelangt in einen Druckkanal vom Druckpfad. b) ab ausreichend großer Druckdifferenz an einem elastatisch vorgespannt beaufschlagten Ventilkörper 13 vom Rückschlagventil 11, hebt der Ventilkörper 13 von seinem Ventilsitz 14 ab, so dass der pulsierende Volumenstrom nach der Dämpfungskammer 8 unmittelbar direkt durch die Blende 9 mit großer Blendenöffnung gelangt. Dabei ist die Vorspannkraft auf den Ventilkörper 13 so vorgegeben, dass beispielsweise vergleichsweise hohe Pulsationswirkung den Umschaltprozess auslöst. Durch diese Schaltmaßnahme umfasst die gebildete Dämpfungskaskade nur die Wirkung der Dämpfungskammer 8 in Kombination mit der Wirkung der Blende 9 mit großer Durchtrittsöffnung .a) if the pressure difference exerted on the check valve 11 is not sufficient to open this, always the upstream aperture 10 is always active with a small aperture. Subsequently, the volume flow passes through the aperture 9 with a large aperture. For this switching state causes the damping unit 7 a cascaded, in other words connected in series, effect of damping chamber 8 and the two connected in series aperture 9.10 with different sized apertures. Subsequently, the pressure medium leaves the damping unit 7 and enters a pressure channel from the pressure path. b) from a sufficiently large pressure difference across an elastically biased acted upon valve body 13 from the check valve 11, the valve body 13 lifts from its valve seat 14, so that the pulsating volume flow passes directly to the damping chamber 8 directly through the aperture 9 with large aperture. In this case, the biasing force on the valve body 13 is predetermined so that, for example, comparatively high pulsation effect triggers the switching process. As a result of this switching measure, the damping cascade formed comprises only the effect of the damping chamber 8 in combination with the effect of the aperture 9 with a large passage opening.
Ein besonderer Vorteil dieser adaptiv wirksamenA particular advantage of this adaptively effective
Dämpfungseinheit 7 ist, dass sie mit den notwendigen Bauteilen einfach in eine modular gestaltete Großserie integrierbar ist, die anhand von unterschiedlichen, modular ausgestatteten Ausführungsformen auf einfachem Wege eine variabel gestaltete, adaptive Pulsationsdämpfung erlaubt, ohne wesentlichen Änderungsaufwand beispielsweise an den elektrohydraulischen Ventilen 2,3, an dem Aufnahmekörper 1, einer elektronischen Regelung oder an anderen Komponenten hervorzurufen. Denn Bauteile der Dämpfungseinheit 7 können einfach, nach Bedarf, im Sinne eines Baukastens hinzugefügt oder weggelassen werden.Damping unit 7 is that it can be easily integrated with the necessary components into a modular designed large series, which allows a variably designed, adaptive pulsation damping based on different, modular equipped embodiments, without significant modification effort, for example, to the electro-hydraulic valves 2,3, to cause the receiving body 1, an electronic control or other components. Because components of the damping unit 7 can be easily added as needed, in the sense of a kit or omitted.
Die Blendenöffnungen der beiden Blenden 9, .10 sind bevorzugt unterschiedlich groß dimensioniert. Beispielsweise verfügen diese ganz generell über einen vergleichsweise kleinen Durchmesser von wenigen Zehntelmillimeter. Eine bevorzugte Stufung der Blendenöffnungen liegt beispielsweise in einem Bereich von etwa 0,2 mm bis 0,5 mm (mit jeweils bis zu +/- 0,25 mm Abweichung) . Folglich ist die Blendenöffnung der Blende 10 im Vergleich zu der Blendenöffnung der Blende 9 nur etwa halb so groß dimensioniert.The apertures of the two apertures 9, 10 are preferably dimensioned differently large. For example, these generally have a comparatively small diameter of a few tenths of a millimeter. A preferred gradation of the apertures is for example in a range of about 0.2 mm to 0.5 mm (each up to +/- 0.25 mm deviation). Consequently, the aperture is the Aperture 10 dimensioned compared to the aperture of the aperture 9 only about half as large.
Mit Blick auf die Fig. 3 sind die physikalischen Wirkungen der Dämpfungseinheit 7 prinzipiell wie folgt. Zunächst ist das hydraulische Druckmittel DM - obwohl prinzipiell inkompressibel, zumindest im Hochdruckbereich geringfügig elastisch (Elastizität des Druckmittels) . Eine weitere zusätzliche Elastizität E ist sinnbildlich durch gesonderte Dämpfungsmittel gegeben. Weiterhin sind die Blenden 9,10 mit Ihrer jeweiligen Blendenöffnung in Hinblick auf bestimmte Pulsationscharakteristiken so dimensioniert, dass ein bestimmter Staudruck in der Dämpfungskammer 8 aufgebaut werden kann, so dass die Dämpfungskammer 8 durch das darin aufgestaute Druckmittelvolumen Elastizität zur Verfügung stellt. Die Aufgabe der gesamten Dämpfungseinheit 7 besteht nun darin, deren Wirkung genau so abzustimmen, dass sämtliche Elastizitäten E in Verbindung mit dem erzeugten Staudruck eine Phasenverschiebung in Relation zu einer Anregungsfrequenz (diese entspricht einer Drehzahl vom elektromotorischen Antrieb) durch die Pumpe 4 derart verursacht, dass die Phasenverschiebung eine Auslöschung von Pulsationswirkungen oder zumindest eine Minderung von Pulsationswirkungen verursacht. Durch die adaptive Charakteristik der Erfindung wird diese Aufgabe sogar im Bereich geringer Antriebsfrequenzen, beispielsweise bei Komfortfunktionen, erzielt .With regard to FIG. 3, the physical effects of the damping unit 7 are basically as follows. First, the hydraulic pressure medium DM - although incompressible in principle, slightly elastic at least in the high pressure area (elasticity of the pressure medium). Another additional elasticity E is symbolically given by separate damping means. Furthermore, the diaphragms 9, 10 with their respective diaphragm opening are dimensioned with regard to certain pulsation characteristics such that a certain dynamic pressure can be built up in the damping chamber 8, so that the damping chamber 8 provides elasticity due to the pressure fluid volume stored therein. The task of the entire damping unit 7 is now to tune their action exactly so that all elasticities E in conjunction with the generated back pressure a phase shift in relation to an excitation frequency (this corresponds to a speed of the electric motor drive) caused by the pump 4 such that the phase shift causes an extinction of Pulsationswirkungen or at least a reduction of Pulsationswirkungen. Due to the adaptive characteristic of the invention, this object is achieved even in the range of low drive frequencies, for example in comfort functions.
Der Mechanismus einer besonders gelungenen Auslöschung oder Minderung ist besonders gut aus der Fig. 6 zu ersehen. Hintergrund ist eine kaskadierte, abschaltbare Abblendung einer Dämpfungskammer 8 mit etwa 100 mm Druckmittelvolumen. In den beiden Druck-Zeit-Diagrammen stellt die obere Kurve jeweils einen Druck in der Dämpfungskammer 8 p D und die untere Kurve einen Druck in einer Radbremse p_VR dar. Das rechte Diagramm in Fig. 6 verdeutlicht einen stark geglätteten Raddruckverlauf p_VR bei einer jeweils erheblichen Überhöhung des Dämpfungskammerdrucks p D im Verhältnis zum Raddruck p VR. Dies lässt auf einen stark überhöhten Staudruck schließen, welcher die erläuterte Phasenverschiebung verursacht. Im Ergebnis zeigt der Raddruckverlauf im Wesentlichen keine Ungleichförmigkeit .The mechanism of a particularly successful extinction or reduction can be seen particularly well from FIG. 6. Background is a cascaded, turn-off dimming of a damping chamber 8 with about 100 mm pressure medium volume. In the two pressure-time diagrams represents the upper curve The right-hand diagram in FIG. 6 illustrates a strongly smoothed wheel pressure curve p_VR with a respectively considerable increase in the damping chamber pressure p D in relation to the wheel pressure p VR. This suggests a greatly inflated dynamic pressure, which causes the explained phase shift. As a result, the wheel pressure waveform shows substantially no nonuniformity.
Demgegenüber beruht ein Dämpfungssystem nach Fig. 7 nicht auf der Grundlage der Erfindung, sondern lediglich auf einer kaskadierten Beblendung von einer Elastomermembran 15 mit etwa 60 Shore Härte (ohne Verwendung von einer Dämpfungskammer) . Dem rechten Diagramm der Fig. 7 ist ein ungleichförmig- treppenförmiger Raddruckverlauf p VR zu entnehmen, wobei der Dämpfungskammerdruck p_D stellenweise bis auf den Raddruck p VR absinkt. Dies dokumentiert eine - in weiten Teilen unbefriedigende - Dämpfungsfunktion der verwendeten Dämpfungseinheit .In contrast, a damping system according to Fig. 7 is not based on the invention, but only on a cascaded blend of an elastomeric membrane 15 with about 60 Shore hardness (without use of a damping chamber). The right-hand diagram of FIG. 7 shows a non-uniform staircase-shaped wheel pressure profile p VR, wherein the damping chamber pressure p_D drops in places down to the wheel pressure p VR. This documents a - largely unsatisfactory - damping function of the damping unit used.
In dem Diagramm gemäß Fig. 4 ist qualitativ eine Kennlinie einer Volumenaufnahme V in mm3 in Abhängigkeit von dem Druck p in bar bei einer erfindungsgemäßen Dämpfungseinheit 7 abgetragen. Demzufolge verdeutlicht die Fig. 4 die jeweils verfügbare Elastizität E. Ein Knick K in der Volumenkennlinie verdeutlicht anschaulich, dass die Elastizität und damit die Blendwirkung durch den beschriebenen Schaltvorgang unter hohem Systemdruck reduziert ist, so dass auch die Volumenaufnahme in der Dämpfungskammer 8 reduziert ist. Beispielsweise beträgt die Elastizität (Steigung der Kennlinie) in einem ersten Abschnitt beispielsweise etwa 6 mm /bar und in einem zweiten Abschnitt etwa 0,5 mm3/bar. Ganz generell ist es von Vorteil, wenn der maximale Staudruck limitiert ist, da überhöhter Staudruck in der Dämpfungskammer 8 durch hydraulische Rückwirkungen auf Kolben und Antriebsexzenter eine erhöhte Stromaufnahme und erhöhten Verschleiß vom Kurbeltrieb verursacht. Aus diesem Grund ist der Bypass 12 mit dem Rückschlagventil 11 vorgesehen, der den maximal erzeugten Staudruck begrenzt. Der Öffnungsdruck vom Rückschlagventil 11 kann bevorzugt umso geringer gewählt werden, je elastischer die Abstimmung des Gesamtsystems (Abstimmung von Dämpfungskammer 8, Blenden 9,10 und Elastizität/Druckmittel) ausgebildet ist.In the diagram according to FIG. 4, a characteristic of a volume absorption V in mm 3 is plotted qualitatively as a function of the pressure p in bar in a damping unit 7 according to the invention. As a result, FIG. 4 illustrates the respectively available elasticity E. A kink K in the volume characteristic graphically illustrates that the elasticity and thus the glare is reduced by the described switching operation under high system pressure, so that the volume absorption in the damping chamber 8 is also reduced. For example, the elasticity (slope of the characteristic curve) in a first section is for example about 6 mm / bar and in a second section about 0.5 mm 3 / bar. Quite generally, it is advantageous if the maximum back pressure is limited because excessive back pressure in the damping chamber 8 caused by hydraulic reactions to the piston and drive eccentric increased power consumption and increased wear from the crank mechanism. For this reason, the bypass 12 is provided with the check valve 11, which limits the maximum generated dynamic pressure. The opening pressure from the check valve 11 can preferably be selected the lower, the more elastic the tuning of the overall system (tuning of the damping chamber 8, diaphragms 9, 10 and elasticity / pressure medium) is formed.
Übereinstimmende Bauelemente sind in Fig. 2 mit übereinstimmenden Bezugsziffern gekennzeichnet. Zusätzlich ist in der Dämpfungskammer 8 eine elastische Membran 15 angeordnet, die die fluidgefüllte Dämpfungskammer 8 von einem pneumatischen Raum 16 trennt. Der pneumatische Raum 16 kann, gemäß einer Ausführungsform, durch einen Verschluß 17 von der Umgebungsatmosphäre U abgetrennt sein. Alternativ dazu erfolgt ein Druckausgleich zwischen dem pneumatischem Raum 16 und der Umgebungsatmosphäre U. Die beiden Blenden 9,10 und das Rückschlagventil 11 sind als gesondert handhabbare Baugruppe ausgebildet, und ausgehend von einer Aufnahmebohrung der Dämpfungskammer 8 in eine abgestufte Bohrung 18 vom Druckkanal eingefügt. Zur Ausbildung der Blende 10 verfügt der Ventilsitz 14 über eine gezielt vorgesehene Kerbe 19, deren Querschnitt der Blendenöffnung entspricht. Um Verstopfung von feinen Bohrungen, insbesondere der Verstopfung der Blendenöffnung vorzubeugen, kann dieser ein Sieb 20 (vgl. Fig. 5) vorgeschaltet sein. Zur Ausbildung kann gegenüber dem Ventilsitz 14 mittig an einem Boden 21 von einem Gehäuse 22 eine Blende 9 vorgesehen sein (Fig. 1) . Alternativ ist - wie in Fig. 5 gezeigt - zwischen Ventilkörper 13 und Ventilsitz 14 eine kanal- oder schlitzförmige Blendenöffnung (Kerbe 19) vorgesehen, und die erweiterte Blendenöffnung wird geschaffen, indem der Ventilkörper 13 vom Ventilsitz 14 abhebt (Fig. 5) . Diese Bauweise zeichnet sich dadurch aus, dass der Querschnitt der Blende 9 in Abhängigkeit von der anliegenden Druckdifferenz sogar variabel eingestellt werden kann, während gemäß Fig. 2 stets ein Festwert definiert ist. Mit anderen Worten ist es durchaus möglich, entweder die Blende 9 oder die Blende 10 variabel zu gestalten.Matching components are identified in Fig. 2 with corresponding reference numerals. In addition, an elastic membrane 15 is arranged in the damping chamber 8, which separates the fluid-filled damping chamber 8 from a pneumatic chamber 16. The pneumatic space 16 may, according to one embodiment, be separated from the ambient atmosphere U by a closure 17. Alternatively, a pressure equalization between the pneumatic chamber 16 and the ambient atmosphere U. The two apertures 9,10 and the check valve 11 are formed as a separate handle assembly, and inserted starting from a receiving bore of the damping chamber 8 in a stepped bore 18 from the pressure channel. To form the diaphragm 10, the valve seat 14 has a specifically provided notch 19, whose cross section corresponds to the diaphragm opening. In order to prevent blockage of fine bores, in particular the obstruction of the aperture, this can be preceded by a sieve 20 (see FIG. For formation, a diaphragm 9 may be provided in the middle of a base 21 of a housing 22 relative to the valve seat 14 (FIG. 1). Alternatively, as shown in Fig. 5, between valve body 13 and valve seat 14, there is provided a channel or slot shaped aperture (notch 19), and the expanded aperture is created by lifting valve body 13 away from valve seat 14 (Fig. 5). This design is characterized by the fact that the cross section of the aperture 9 can be set even variable depending on the applied pressure difference, while according to FIG. 2, a fixed value is always defined. In other words, it is quite possible to make either the diaphragm 9 or the diaphragm 10 variable.
Weiterhin kann die Schaltlogik unterschiedlich umgesetzt werden, indem beispielsweise wie in Fig. 1 die Blende 10 abgeschaltet wird, weil ein Rückschlagventil 11 den Bypass 12 öffnet, oder die Blende 10 wird im Sinne einer Schaltblende druckabhängig geöffnet (Fig. 2) .Furthermore, the switching logic can be implemented differently by, for example, as in Fig. 1, the aperture 10 is turned off, because a check valve 11 opens the bypass 12, or the aperture 10 is opened in the sense of a switching diaphragm pressure dependent (Fig. 2).
Die Dämpfungseinheit 7 kann selbstreinigende Eigenschaften aufweisen, indem feine Blendenbohrungen im Betrieb während Phasen höherer Drücke/Antriebsdrehzahlen freigespült werden. Sollten Schmutzpartikel irgendwelche Blendenöffnungen während Niederdruckphasen vollständig verstopfen, steigt der Druck in der Dämpfungskammer 8 automatisch an, und das Rückschlagventil 11 öffnet. Somit wird eine Überlastung der Pumpe 4 verhindert, die sichere Funktion ist weiterhin sichergestellt, und die feine Blende 9 wird während Phasen hohen Drucks gereinigt (Selbstheilungsverhalten) .The damping unit 7 may have self-cleaning properties by flushing fine orifices during operation during phases of higher pressures / drive speeds. Should dirt particles clog any apertures completely during low pressure phases, the pressure in the damping chamber 8 will automatically increase and the check valve 11 will open. Thus, an overload of the pump 4 is prevented, the safe function is further ensured, and the fine aperture 9 is cleaned during phases of high pressure (self-healing behavior).
Der Fig. 5 ist eine weitere, abgewandelte Ausführungsform der Erfindung zu entnehmen. Um das Volumen-Druckverhalten der Dämpfungskammer 8 nach Bedarf zu modellieren, sind mehrere metallische Elastokörper 23 in der Dämpfungskammer 8 aufgenommen. Die Elastokörper 23 können beispielsweise wie eine hermetisch dicht geschlossene, kompressible Barometerdose ausgeführt sein. Die Elastokörper 23 dienen zur Beeinflussung und Herstellung der gewünschten Elastizität E. Ein weiterer Vorteil besteht darin, dass durch die Volumenaufnahme relativ wenig Bremsflüssigkeitsvolumen in den Aufnahmekörper eingefüllt werden muss, und dass gleichzeitig eine definierte Elastizität vorgesehen ist. FIG. 5 shows a further, modified embodiment of the invention. In order to model the volume-pressure behavior of the damping chamber 8 as required, a plurality of metallic elastomer bodies 23 are in the damping chamber 8 added. The Elastokörper 23 may be designed, for example, as a hermetically sealed, compressible barometer. The Elastokörper 23 serve to influence and produce the desired elasticity E. Another advantage is that relatively little volume of brake fluid must be filled into the receiving body by the volume absorption, and that at the same time a defined elasticity is provided.
Bezugs zeichenlisteReference sign list
1 Aufnahmekörper1 receiving body
2 elektrohydraulisches Ventil2 electrohydraulic valve
3 elektrohydraulisches Ventil3 electrohydraulic valve
4 Pumpe4 pump
5 Saugventil5 suction valve
6 Druckventil6 pressure valve
7 Dämpfungseinheit7 damping unit
8 Dämpfungskammer8 damping chamber
9 Blende9 aperture
10 Blende10 aperture
11 Rückschlagventil11 check valve
12 Bypass12 bypass
13 Ventilkörper13 valve body
14 Ventilsitz14 valve seat
15 Membran15 membrane
16 Raum16 room
17 Verschluss17 closure
18 Bohrung18 hole
19 Kerbe19 notch
20 Sieb20 sieve
21 Boden21 floor
22 Gehäuse22 housing
23 Elastokörper23 elasto body
HCU HydraulikaggregatHCU hydraulic unit
K KnickK kink
M MotorM engine
THZ BetätigungseinheitTHZ actuation unit
B RadbremseB wheel brake
DM Druckmittel E ElastizitätDM pressure medium E elasticity
U Umgebungsatmosphäre p DruckU ambient atmosphere p pressure
V Volumen p_D Dämpfungskammerdruck p VR Radbremsdruck t Zeit V volume p_D damping chamber pressure p VR wheel brake pressure t time

Claims

Patentansprüche claims
1. Hydraulikaggregat (HCU) umfassend einen Aufnahmekörper (1) mit elektrohydraulischen Ventilen (2,3), mit wenigstens einer hydraulischen Pumpe (4), und mit Kanälen zur Verbindung der Pumpe (4) mit wenigstens einem hydraulischen Verbraucher, wobei infolge Druckmittelförderung durch die Pumpe (4) und/oder infolge Druckmittelentnahme durch den Verbraucher eine Pulsationssituation gegeben ist, und dass wenigstens eine Dämpfungseinheit (7) vorgesehen ist, welche mehrere Pulsationsdämpfungsmittel wie insbesondere1. Hydraulic unit (HCU) comprising a receiving body (1) with electro-hydraulic valves (2,3), with at least one hydraulic pump (4), and with channels for connecting the pump (4) with at least one hydraulic consumer, wherein due to pressure medium promotion by the pump (4) and / or as a result of pressure medium removal by the consumer a pulsation situation is given, and that at least one damping unit (7) is provided which several Pulsationsdämpfungsmittel such as in particular
Dämpfungskammer (8), Blende (9,10) aufweist, dadurch gekennzeichnet, dass die Dämpfungseinheit (7) wenigstens ein Schaltmittel aufweist, um die Wirkung dieser Dämpfungseinheit (7) durch Zu- oder Abschaltung von einem oder von mehreren Dämpfungsmitteln, an eine veränderte Pulsationssituation anzupassen.Damping chamber (8), diaphragm (9,10), characterized in that the damping unit (7) has at least one switching means to the effect of this damping unit (7) by switching on or off of one or more damping means to a changed Adjust pulsation situation.
2. Hydraulikaggregat nach Anspruch 1, dadurch gekennzeichnet, dass das Schaltmittel als Ventil und/oder als Schaltblende ausgebildet ist, und dass dem Ventil und/oder der Schaltblende ein Pulsationsdämpfungsmittel parallel geschaltet ist.2. Hydraulic unit according to claim 1, characterized in that the switching means is designed as a valve and / or as a switching diaphragm, and that the valve and / or the switching diaphragm a Pulsationsdämpfungsmittel is connected in parallel.
3. Hydraulikaggregat nach Anspruch 2, dadurch gekennzeichnet, dass das Schaltmittel als elektromagnetisch geschaltetes Ventil ausgebildet ist.3. Hydraulic unit according to claim 2, characterized in that the switching means is designed as an electromagnetically switched valve.
4. Hydraulikaggregat nach Anspruch 2, dadurch gekennzeichnet, dass das Schaltmittel als hydraulisch geschaltetes Ventil ausgebildet ist. 4. Hydraulic unit according to claim 2, characterized in that the switching means is designed as a hydraulically switched valve.
5. Hydraulikaggregat nach Anspruch 3 oder 4, dadurch gekennzeichnet, dass das Ventil als Rückschlagventil (11) ausgebildet ist, dass das Rückschlagventil (11) eine integrierte Blende (9,10) aufweist, und dass das Rückschlagventil (11) einen vorbestimmten Öffnungsdruck aufweist, indem ein Ventilkörper (13) mit einer definierten Vorspannkraft beaufschlagt ist.5. Hydraulic unit according to claim 3 or 4, characterized in that the valve is designed as a check valve (11), that the check valve (11) has an integrated aperture (9,10), and that the check valve (11) has a predetermined opening pressure by a valve body (13) is acted upon by a defined biasing force.
6. Hydraulikaggregat nach Anspruch 2 und 5, dadurch gekennzeichnet, dass das Rückschlagventil (11) im Grundzustand geschlossen ist, und dass der vorbestimmte Öffnungsdruck abgestimmt ist, um das parallel geschaltete Pulsationsdämpfungsmittel zu umgehen oder außer Funktion zu schalten .6. Hydraulic unit according to claim 2 and 5, characterized in that the check valve (11) is closed in the ground state, and that the predetermined opening pressure is adjusted to bypass the parallel-connected Pulsationsdämpfungsmittel or disable function.
7. Hydraulikaggregat nach einem oder mehreren der vorhergehenden Ansprüche, dadurch gekennzeichnet, dass eine Blende (10) als Kanal oder Kerbe (19) in einem Ventilsitz7. Hydraulic unit according to one or more of the preceding claims, characterized in that a diaphragm (10) as a channel or notch (19) in a valve seat
(14) ausgebildet ist.(14) is formed.
8. Hydraulikaggregat nach einem oder mehreren der vorhergehenden Ansprüche, dadurch gekennzeichnet, dass die Dämpfungskammer (8) einen oder mehrere Elastokörper (23) aufnimmt . 8. Hydraulic unit according to one or more of the preceding claims, characterized in that the damping chamber (8) receives one or more Elastokörper (23).
EP09708798A 2008-02-08 2009-02-04 Hydraulic system with improved pulsation damping Withdrawn EP2250057A1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
DE102008008271 2008-02-08
DE102009006980A DE102009006980A1 (en) 2008-02-08 2009-01-30 Hydraulic unit with improved pulsation damping
PCT/EP2009/051277 WO2009098235A1 (en) 2008-02-08 2009-02-04 Hydraulic system with improved pulsation damping

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EP2250057A1 true EP2250057A1 (en) 2010-11-17

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US (1) US8671680B2 (en)
EP (1) EP2250057A1 (en)
KR (1) KR101548401B1 (en)
CN (1) CN101939198B (en)
DE (1) DE102009006980A1 (en)
WO (1) WO2009098235A1 (en)

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KR20100108619A (en) 2010-10-07
US20100319334A1 (en) 2010-12-23
CN101939198A (en) 2011-01-05
WO2009098235A1 (en) 2009-08-13
CN101939198B (en) 2013-11-13
US8671680B2 (en) 2014-03-18
KR101548401B1 (en) 2015-08-28
DE102009006980A1 (en) 2009-08-13

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