EP1834089B1 - Piston pump, particularly a high-pressure fuel pump for an internal combustion engine - Google Patents

Piston pump, particularly a high-pressure fuel pump for an internal combustion engine Download PDF

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Publication number
EP1834089B1
EP1834089B1 EP05797277A EP05797277A EP1834089B1 EP 1834089 B1 EP1834089 B1 EP 1834089B1 EP 05797277 A EP05797277 A EP 05797277A EP 05797277 A EP05797277 A EP 05797277A EP 1834089 B1 EP1834089 B1 EP 1834089B1
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EP
European Patent Office
Prior art keywords
piston
piston pump
pump
working space
sleeve part
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EP05797277A
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German (de)
French (fr)
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EP1834089A1 (en
Inventor
Heinz Siegel
Thomas Jakisch
Siamend Flo
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Robert Bosch GmbH
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Robert Bosch GmbH
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Publication of EP1834089A1 publication Critical patent/EP1834089A1/en
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B1/00—Multi-cylinder machines or pumps characterised by number or arrangement of cylinders
    • F04B1/04—Multi-cylinder machines or pumps characterised by number or arrangement of cylinders having cylinders in star- or fan-arrangement
    • F04B1/0404—Details or component parts
    • F04B1/0408—Pistons

Definitions

  • the invention relates to a piston pump, in particular a fuel pump high-pressure pump for an internal combustion engine, with a housing and with a piston which defines a working space and has a pointing away from the working space paragraph.
  • a piston pump of the type mentioned is from the DE 101 34 066 A1 known.
  • the piston can be offset by an eccentric shaft in a reciprocating motion.
  • the piston has a region with a larger diameter and a region with a smaller diameter, wherein the region of larger diameter is in the installed position adjacent to the working space.
  • the piston is guided in the known pump with the larger diameter region directly in the housing and inserted with this area ahead of the working space forth in the housing.
  • the opening through which the piston is inserted into the housing is closed by a quantity control valve after insertion of the piston.
  • Object of the present invention is to provide a piston pump of the type mentioned in such a way that it can be made faster and easier.
  • the piston can be introduced with the working space end in front of the housing, the piston can be inserted through the same opening in which it is later performed in operation in the housing. An additional opening for the assembly of the piston can thus be omitted.
  • This increases the freedom in the design of the piston pump, reduces the cost of the housing, and reduces assembly costs. After insertion of the piston into the housing and before assembly of the piston pump, for example on an internal combustion engine, falling out is still reliably prevented by the stop element.
  • the pump can therefore be supplied in preassembled state to the manufacturer of the internal combustion engine. This simplifies storage, transport and integration into the internal combustion engine.
  • the shoulder is formed by an annular step on the piston.
  • a stepped piston can be easily and inexpensively manufactured.
  • the proposed annular step on the piston still has the advantage that in this area, the piston pump can build a total of smaller, which further facilitates their installation in the engine.
  • the annular step delimits a compensation chamber which is fluidically separated from the working chamber and which is connected to a region of an inlet-side volume control valve remote from the working chamber.
  • a pressure damper is arranged between the equalization chamber and the quantity control valve in such a piston pump. Due to the presence of the compensation chamber of the pressure damper can build smaller, which contributes to a total reduction of the dimensions of the piston pump according to the invention. Due to the compensation volume provided in the compensation room In addition, pressure peaks, which can occur in the event of failure of the pressure damper, are reduced. As a result, the inlet side parts of the piston pump and also a low pressure system connected to the inlet of the piston pump can be designed for maximum pressures, which also contributes to simplification and cost reduction.
  • the hydraulically effective area of the annular step is approximately half the size of the hydraulically effective area of the piston projecting into the working space. "About half the size” includes a range of 40-60% of the hydraulic effective area of the piston projecting into the working space.
  • the stop element comprises a sleeve part which is coaxial to the piston and has a radially inner region on which the stop is formed.
  • a sleeve part can be produced inexpensively, for example, as a sheet metal part.
  • the stop element may comprise a sleeve part which is coaxial with the piston and which has an axially extending fastening section on a radially outer region, on which the sleeve part is connected to the housing, preferably pressed in and / or welded.
  • the attachment of the stop element is moved to the housing in a radially comparatively far outboard area, which is at most far away from the piston and the piston seal.
  • the risk of damage to these sensitive parts during assembly or manufacture of the piston pump according to the invention is thus reduced. This is especially true for attachment of the stop element to the housing by a weld, in the production of which welding spatter can occur and In addition, there may be a delay of lying in the vicinity of the weld components.
  • a particularly advantageous embodiment of the piston pump according to the invention is characterized in that it comprises a housing-fixed piston seal, which rests against a lateral surface of the piston and a conveying region separated from a drive region, and that the piston seal is held by a holding portion of the stop element.
  • the stop element thus has a dual function, namely it additionally holds the piston seal.
  • the circumference to be sealed is also reduced, which directly translates into reduced leakage from the fuel to a drive region and vice versa (the drive region is usually at least one with lubricant) partly filled or contaminated area).
  • the stop element may comprise a first sleeve part on which the stopper is present, and a second sleeve part which holds the piston seal. These can be produced with little effort.
  • the holding section comprises a receiving chamber, in which the piston seal is received, and which is formed between the first sleeve part and the second sleeve part.
  • a receiving chamber allows a simple and safe and beyond a protected mounting of the piston seal.
  • a simple joining method for the two sleeve parts is that they are pressed together. In contrast to a welded connection, a delay of the stop element is also avoided.
  • the two sleeve parts and the piston seal form a preassembled module.
  • This pre-assembled assembly is postponed after insertion of the piston in the guide opening of the housing on the piston as a whole, whereby assembly time is saved.
  • the piston spring can be placed and then attached to the end remote from the working space of the piston, a spring plate, for example by a press connection.
  • the piston can be pressed with its working space end against the opposite boundary wall of the working space without the risk of damage, for example, a quantity control valve.
  • a fuel system carries in FIG. 1 overall, the reference numeral 10. It comprises a fuel tank 12, from which a prefeed pump 14 conveys the fuel to a piston pump designed as a high-pressure fuel pump 16. This compresses the fuel to a very high pressure and conveys it to a fuel rail 18, to which a plurality of injectors 20 are connected. These inject the fuel directly into their associated combustion chambers 22 a.
  • the piston pump 16 is mechanically driven by the internal combustion engine, as indicated by the connection 24. To control the Flow rate of the piston pump 16 includes this inlet side a quantity control valve 26th
  • the piston pump 16 is in FIG. 2 It is shown in more detail in detail: Thereafter, it comprises a total of approximately cylindrical housing 28, which in FIG. 2 is closed at the top by a cover 30. Under the lid, as will be explained below, an in FIG. 2 invisible pressure damper arranged.
  • a stepped bore 32 is introduced into the housing 28, into which a piston bushing 34 is inserted. In the latter, in turn, a piston 36 is guided axially displaceable with very little play.
  • the piston 36 and the in FIG. 2 Upper end of the stepped bore 32 define a working space 38, in which the fuel from the side of the housing 28 arranged quantity control valve 26 passes through an inlet 40 during a suction stroke. During a compression stroke of the piston 36, the fuel is expelled from the working space 38 via an outlet 42 to the fuel rail 18.
  • the piston 36 is formed as a stepped piston with a working space 38 toward the area 44 of larger diameter and a remote from the working space 38 area 46 with a smaller diameter. Between the two regions 44 and 46 of the piston 36, an annular step 48 is provided through which a shoulder is formed, which will be discussed in more detail below. Typical diameters for the regions 44 and 46 are 9 and 6 mm, respectively. How out FIG. 2 it can be seen, the housing 28 is inserted with a connecting piece 50 in a receiving opening 52 in an engine block 54 of the internal combustion engine. That of the work space 38 remote end of the piston 36 cooperates with an eccentric portion 56 of the drive shaft 24 together.
  • FIG. 3 Assembly 58, shown in greater detail, is mounted to housing 28, which includes a stop member 60 and a piston seal 62.
  • the stop element 60 in turn consists of a first sleeve part 64 and a second sleeve part 66. Both sleeve parts 64 and 66 and the piston seal 62 are arranged coaxially with the piston 36.
  • the piston seal 62 rests in the installed position on the lateral surface of the piston 36 and separates a fuel-side delivery region 68 from a motor oil-side drive region 70 (cf. FIG. 2 ).
  • the first sleeve part 64 comprises a radially inner and tubular axially extending inner portion 72, a radially extending central portion 74, which is integrally formed on the working space 38 and the conveying area 68 towards the end of the inner portion 72, and a radially outwardly to the central portion 74 formed outer portion 76 which extends in the axial direction to the drive portion 70 through.
  • the second sleeve part 66 comprises an annular and radially inner inner portion 78, a radially outwardly formed on the inner portion 78 central portion 80 which extends in the axial direction of the working space 38 and the conveying region 68 and an integrally formed on the central portion 80 outer portion 82, which extends radially outward.
  • the outer diameter of the central portion 80 of the second sleeve portion 66 and the inner diameter of the inner portion 72 of the first sleeve portion 64 are at least partially coordinated so that the inner portion 78 and the central portion 80 of the second sleeve portion 66 are held by a press fit within the first sleeve portion 64.
  • a short, radially inwardly directed turn 84 is present at the free end of the inner portion 72 of the first sleeve portion 64 facing away from the working space 38 and from the conveying area 68.
  • This bend 84 together with a portion of the inner portion 72 of the first sleeve portion 64 and the inner portion 78 of the second sleeve portion 66, forms a retainer portion for the piston seal 62 in the form of an annular receiving chamber 86.
  • the assembly 58 is pushed onto the region 46 of the piston 36 after the assembly of the piston 36.
  • the outside of the outer portion 76 of the first sleeve part 64 is then pressed in 88 and welded to the connection piece 50 of the housing 28.
  • a piston spring 90 is mounted, the diameter of which is selected so that it is supported axially at one end to the inner portion 72 of the first sleeve portion 64 adjacent region of the central portion 74.
  • the portion of the inner portion 72 adjacent to the central portion 74 has a slightly increased diameter, by which the piston spring 90 is centered without its free mobility being restricted by the inner portion 72 as a whole.
  • the shoulder 48 Since the outer diameter of the portion 44 of the piston 36 is greater than the inner diameter of the inner portion 78 of the second sleeve member 66, the shoulder 48, as long as the piston pump 16 is not yet inserted into the receiving opening 52, in abutment against the inner portion 78 of the second sleeve member 66th This thus forms a stop for the shoulder 48 of the piston 36 and prevents the piston 36 from falling out of the fully assembled piston pump 16, as long as it is not yet attached to the engine block 54 of the internal combustion engine. It is understood that after installation of the piston pump 16 in the receiving opening 52 in the engine block 54, a contact between the stopper 78 and the shoulder 48 is excluded, as in FIG. 2 shown.
  • FIG. 2 It is also apparent that the piston 36, the second sleeve part 66, and the central portion 74 of the first sleeve member 64, and the housing 28, a compensation chamber 94 is limited, via a channel 96 with the pressure damper (reference numeral 98 in the FIGS. 4 and 5 ) connected is. With the pressure damper 98 is further connected via a channel 100 remote from the working space 38 portion of the quantity control valve.
  • the function of the compensation chamber 94 results from the FIGS. 4 and 5 : During a suction stroke ( FIG. 4 ) The piston 36 moves in the direction of arrow 102. Through the combined intake and quantity control valve 26, fuel flows from the pressure damper 98 and from the compensation chamber 94 via the channel 96 into the working space 38 Pressure damper 98 connected via a channel 104 to the outlet of the feed pump 14.
  • the inlet / quantity control valve 26 is opened during the compression stroke, whereby high-pressure fuel flows out of the working space 38 in accordance with the arrows 110.
  • a resulting pressure pulsation is reduced on the one hand by the pressure damper 98, on the other hand, the outflowing fuel volume is also absorbed by the volume of the expansion chamber 94 which increases during a compression stroke.
  • the corresponding stroke volume in the compensation chamber 94 is determined by the area of the shoulder 48 between the two regions 44 and 46 of the piston 36. It is in FIG. 5 indicated by a dotted line 112 and is approximately 40-60% of the stroke volume in the working space 38 (reference numeral 114 in FIG. 4 ).
  • the filling of the working space 38 is supported during the suction stroke by the decreasing volume of the compensation chamber 94. This leads to an improvement of the dynamics and also of the efficiency of the piston pump 10.

Description

Stand der TechnikState of the art

Die Erfindung betrifft eine Kolbenpumpe, insbesondere eine Kraftstoffpumpe-Hochdruckpumpe für eine Brennkraftmaschine, mit einem Gehäuse und mit einem Kolben, der einen Arbeitsraum begrenzt und einen vom Arbeitsraum weg weisenden Absatz aufweist.The invention relates to a piston pump, in particular a fuel pump high-pressure pump for an internal combustion engine, with a housing and with a piston which defines a working space and has a pointing away from the working space paragraph.

Eine Kolbenpumpe der eingangs genannten Art ist aus der DE 101 34 066 A1 bekannt. In dieser wird eine Einzylinder-Kolbenpumpe beschrieben, deren Kolben von einer Exzenterwelle in eine Hin- und Herbewegung versetzt werden kann. Der Kolben weist einen Bereich mit größerem und einen Bereich mit kleinerem Durchmesser auf, wobei der Bereich mit größerem Durchmesser in Einbaulage zum Arbeitsraum benachbart ist. Der Kolben ist bei der bekannten Pumpe mit dem Bereich größeren Durchmessers unmittelbar im Gehäuse geführt und mit diesem Bereich voraus vom Arbeitsraum her in das Gehäuse eingesetzt. Die Öffnung, über die der Kolben in das Gehäuse eingesetzt wird, wird nach dem Einsetzen des Kolbens durch ein Mengensteuerventil verschlossen.
Nach dem Einsetzen des Kolbens in das Gehäuse wird auf das vom Arbeitsraum abgewandte Ende des Kolbens eine Kolbenfeder aufgeschoben und anschließend an diesem Ende ein Federteller befestigt, an dem sich die Kolbenfeder abstützen kann. Zur Befestigung des Federtellers ist in den Kolben eine Nut eingebracht, in den ein Sprengring eingreift, an dem sich der Federteller wiederum abstützt.A piston pump of the type mentioned is from the DE 101 34 066 A1 known. In this a single-cylinder piston pump is described, the piston can be offset by an eccentric shaft in a reciprocating motion. The piston has a region with a larger diameter and a region with a smaller diameter, wherein the region of larger diameter is in the installed position adjacent to the working space. The piston is guided in the known pump with the larger diameter region directly in the housing and inserted with this area ahead of the working space forth in the housing. The opening through which the piston is inserted into the housing is closed by a quantity control valve after insertion of the piston.
After insertion of the piston in the housing is on the side facing away from the working space end of the piston a Pushed piston spring and then attached to this end a spring plate on which the piston spring can be supported. To fasten the spring plate, a groove is introduced into the piston, in which a snap ring engages, on which the spring plate is supported again.

Aufgabe der vorliegenden Erfindung ist es, eine Kolbenpumpe der eingangs genannten Art so weiterzubilden, dass sie schneller und einfacher hergestellt werden kann.Object of the present invention is to provide a piston pump of the type mentioned in such a way that it can be made faster and easier.

Diese Aufgabe wird bei einer Kolbenpumpe der eingangs genannten Art dadurch gelöst, dass der Kolben mit dem arbeitsraumseitigen Ende voran in das Gehäuse eingeführt und am Gehäuse ein Anschlagelement befestigt ist, welches einen Anschlag aufweist, der wenigstens zeitweise mit dem Absatz zusammenarbeitet.This object is achieved in a piston pump of the type mentioned above in that the piston with the working space end first inserted into the housing and the housing a stop element is attached, which has a stop which cooperates at least temporarily with the paragraph.

Vorteile der ErfindungAdvantages of the invention

Dadurch, dass der Kolben mit dem arbeitsraumseitigen Ende voran in das Gehäuse eingeführt werden kann, kann der Kolben durch die gleich Öffnung eingeführt werden, in der er später im Betrieb im Gehäuse geführt ist. Eine zusätzliche Öffnung für die Montage des Kolbens kann somit entfallen. Dies erhöht die Freiheiten bei der Auslegung der Kolbenpumpe, verringert die Herstellungskosten des Gehäuses, und verringert den Montageaufwand. Nach dem Einführen des Kolbens in das Gehäuse und vor der Montage der Kolbenpumpe beispielsweise an einer Brennkraftmaschine wird dennoch ein Herausfallen zuversichtlich durch das Anschlagelement verhindert. Die Pumpe kann daher in vormontiertem Zustand an der Hersteller der Brennkraftmaschine geliefert werden. Dies vereinfacht Lagerung, Transport und die Integration in die Brennkraftmaschine.Characterized in that the piston can be introduced with the working space end in front of the housing, the piston can be inserted through the same opening in which it is later performed in operation in the housing. An additional opening for the assembly of the piston can thus be omitted. This increases the freedom in the design of the piston pump, reduces the cost of the housing, and reduces assembly costs. After insertion of the piston into the housing and before assembly of the piston pump, for example on an internal combustion engine, falling out is still reliably prevented by the stop element. The pump can therefore be supplied in preassembled state to the manufacturer of the internal combustion engine. This simplifies storage, transport and integration into the internal combustion engine.

Bei einer vorteilhaften Weiterbildung der erfindungsgemäßen Kolbenpumpe ist der Absatz durch eine ringförmige Stufe am Kolben gebildet. Ein solcher Stufenkolben kann einfach und preiswert hergestellt werden. Ferner hat die vorgeschlagene ringförmige Stufe am Kolben noch den Vorteil, dass in diesem Bereich die Kolbenpumpe insgesamt kleiner bauen kann, was deren Einbau in die Brennkraftmaschine nochmals erleichtert.In an advantageous development of the piston pump according to the invention, the shoulder is formed by an annular step on the piston. Such a stepped piston can be easily and inexpensively manufactured. Furthermore, the proposed annular step on the piston still has the advantage that in this area, the piston pump can build a total of smaller, which further facilitates their installation in the engine.

In Weiterbildung hierzu wird vorgeschlagen, dass die ringförmige Stufe einen vom Arbeitsraum fluidisch getrennten Ausgleichsraum begrenzt, der mit einem vom Arbeitsraum abgelegenen Bereich eines einlassseitigen Mengensteuerventils verbunden ist. Beim Betrieb eines solchen einlassseitigen Mengensteuerventils kann es während eines Förderhubs des Kolbens zu erheblichen Druckpulsationen im Bereich des Einlasses der Kolbenpumpe kommen. Durch die ringförmige Stufe und den Ausgleichsraum wird während eines Förderhubs ein zusätzliches sich im Verlauf des Förderhubs vergrößerndes Ausgleichsvolumen geschaffen, welches für die Dämpfung derartiger Druckpulsationen zur Verfügung steht. Darüber hinaus wird bei einer solchen Kolbenpumpe im Betrieb die Druckdifferenz zwischen Ausgleichsraum und Arbeitsraum reduziert, was Leckagen durch einen Führungsspalt des Kolbens hindurch vermindert und so den Wirkungsgrad der Kolbenpumpe erhöht.In a further development, it is proposed that the annular step delimits a compensation chamber which is fluidically separated from the working chamber and which is connected to a region of an inlet-side volume control valve remote from the working chamber. During the operation of such an inlet-side quantity control valve, during a delivery stroke of the piston considerable pressure pulsations may occur in the region of the inlet of the piston pump. Through the annular step and the compensation chamber, an additional compensation volume which increases in the course of the delivery stroke is created during a delivery stroke, which is available for the damping of such pressure pulsations. Moreover, in such a piston pump during operation, the pressure difference between the expansion chamber and the working space is reduced, which reduces leakage through a guide gap of the piston and thus increases the efficiency of the piston pump.

Besonders vorteilhaft ist es, wenn bei einer solchen Kolbenpumpe zwischen Ausgleichsraum und Mengensteuerventil ein Druckdämpfer angeordnet ist. Durch das Vorhandensein des Ausgleichsraums kann der Druckdämpfer kleiner bauen, was insgesamt zu einer Reduzierung der Abmessungen der erfindungsgemäßen Kolbenpumpe beiträgt. Durch das im Ausgleichsraum zur Verfügung gestellte Ausgleichsvolumen werden darüber hinaus Druckspitzen, die im Versagensfall des Druckdämpfers auftreten können, reduziert. In der Folge können die einlassseitigen Teile der Kolbenpumpe und auch ein an den Einlass der Kolbenpumpe angeschlossenes Niederdrucksystem für maximale Drücke ausgelegt werden, was ebenfalls zur Vereinfachung und Kostenreduzierung beiträgt.It is particularly advantageous if a pressure damper is arranged between the equalization chamber and the quantity control valve in such a piston pump. Due to the presence of the compensation chamber of the pressure damper can build smaller, which contributes to a total reduction of the dimensions of the piston pump according to the invention. Due to the compensation volume provided in the compensation room In addition, pressure peaks, which can occur in the event of failure of the pressure damper, are reduced. As a result, the inlet side parts of the piston pump and also a low pressure system connected to the inlet of the piston pump can be designed for maximum pressures, which also contributes to simplification and cost reduction.

Besonders vorteilhaft ist es, wenn die hydraulisch wirksame Fläche der ringförmigen Stufe in etwas halb so groß wie die in den Arbeitsraum ragende hydraulisch wirksame Fläche des Kolbens ist. "In etwa halb so groß" schließt einen Bereich von 40-60% der in den Arbeitsraum ragenden hydraulisch wirksamen Fläche des Kolbens ein.It is particularly advantageous if the hydraulically effective area of the annular step is approximately half the size of the hydraulically effective area of the piston projecting into the working space. "About half the size" includes a range of 40-60% of the hydraulic effective area of the piston projecting into the working space.

Eine weitere Konkretisierung der erfindungsgemäßen Kolbenpumpe sieht vor, dass das Anschlagelement ein zum Kolben koaxiales Hülsenteil mit einem radial innenliegenden Bereich umfasst, an dem der Anschlag ausgebildet ist. Ein solches Hülsenteil kann beispielsweise als Blechformteil preiswert hergestellt werden.A further concretization of the piston pump according to the invention provides that the stop element comprises a sleeve part which is coaxial to the piston and has a radially inner region on which the stop is formed. Such a sleeve part can be produced inexpensively, for example, as a sheet metal part.

Ferner kann das Anschlagelement ein zum Kolben koaxiales Hülsenteil umfassen, welches an einem radial außenliegenden Bereich einen axial verlaufenden Befestigungsabschnitt aufweist, an dem das Hülsenteil mit dem Gehäuse verbunden, vorzugsweise eingepresst und/oder verschweißt ist. Hierdurch wird die Befestigung des Anschlagelements am Gehäuse in einen radial vergleichsweise weit außenliegenden Bereich verlegt, der vom Kolben und der Kolbendichtung maximal weit entfernt ist. Das Risiko einer Beschädigung dieser empfindlichen Teile bei der Montage beziehungsweise Herstellung der erfindungsgemäßen Kolbenpumpe wird somit reduziert. Dies trifft insbesondere für eine Befestigung des Anschlagelements am Gehäuse durch eine Schweißnaht zu, bei deren Herstellung Schweißspritzer auftreten können und bei der es darüber hinaus zu einem Verzug von in der Nähe der Schweißstelle liegenden Bauteilen kommen kann.Furthermore, the stop element may comprise a sleeve part which is coaxial with the piston and which has an axially extending fastening section on a radially outer region, on which the sleeve part is connected to the housing, preferably pressed in and / or welded. As a result, the attachment of the stop element is moved to the housing in a radially comparatively far outboard area, which is at most far away from the piston and the piston seal. The risk of damage to these sensitive parts during assembly or manufacture of the piston pump according to the invention is thus reduced. This is especially true for attachment of the stop element to the housing by a weld, in the production of which welding spatter can occur and In addition, there may be a delay of lying in the vicinity of the weld components.

Diese Vorteile sind dann besonders prägnant, wenn sich eine Kolbenfeder an einem sich radial erstreckenden Abschnitt des Hülsenteils abstützt, der radial einwärts von dem axialen Befestigungsabschnitt angeordnet ist. Darüber hinaus erfüllt ein solches Anschlagelement nun noch eine dritte Funktion, nämlich die Abstützung der Kolbenfeder. Dies reduziert nochmals den Herstellungs- und Montageaufwand und gestattet eine Verringerung der Abmessungen der Kolbenpumpe.These advantages are particularly significant when a piston spring is supported on a radially extending portion of the sleeve member which is disposed radially inwardly of the axial mounting portion. In addition, such a stop element now fulfills a third function, namely the support of the piston spring. This again reduces the manufacturing and assembly costs and allows a reduction in the dimensions of the piston pump.

Eine besonders vorteilhafte Ausgestaltung der erfindungsgemäßen Kolbenpumpe zeichnet sich dadurch aus, dass sie eine gehäusefeste Kolbendichtung umfasst, welche an einer Mantelfläche des Kolbens anliegt und einen Förderbereich von einem Antriebsbereich trennt, und dass die Kolbendichtung von einem Halteabschnitt des Anschlagelementes gehalten wird. Bei dieser Kolbenpumpe hat das Anschlagelement also eine Doppelfunktion, es haltert nämlich zusätzlich die Kolbendichtung. Eine solche Doppelfunktion eines Bauteils der Kolbenpumpe trägt bei Herstellung und Montage zu einer Kostenreduktion bei und gestattet darüber hinaus eine kleinere Bauweise der erfindungsgemäßen Kolbenpumpe.
Wenn die Kolbendichtung bei einem abgestuften Kolben an jenem Kolbenbereich anliegt, der einen kleineren Durchmesser aufweist, wird darüber hinaus der abzudichtende Umfang reduziert, was sich direkt in einer reduzierten Leckage vom Kraftstoff zu einem Antriebsbereich und umgekehrt auswirkt (der Antriebsbereich ist üblicherweise ein mit Schmiermittel wenigstens zum Teil gefüllter bzw. kontaminierter Bereich).A particularly advantageous embodiment of the piston pump according to the invention is characterized in that it comprises a housing-fixed piston seal, which rests against a lateral surface of the piston and a conveying region separated from a drive region, and that the piston seal is held by a holding portion of the stop element. In this piston pump, the stop element thus has a dual function, namely it additionally holds the piston seal. Such a dual function of a component of the piston pump contributes to manufacturing and assembly to a cost reduction and also allows a smaller design of the piston pump according to the invention.
When the piston seal abuts on a piston having a smaller diameter in a stepped piston, the circumference to be sealed is also reduced, which directly translates into reduced leakage from the fuel to a drive region and vice versa (the drive region is usually at least one with lubricant) partly filled or contaminated area).

Das Anschlagelement kann ein erstes Hülsenteil, an dem der Anschlag vorhanden ist, und ein zweites Hülsenteil, welches die Kolbendichtung hält, umfassen. Diese können mit geringem Aufwand hergestellt werden.The stop element may comprise a first sleeve part on which the stopper is present, and a second sleeve part which holds the piston seal. These can be produced with little effort.

In Weiterbildung hierzu wird vorgeschlagen, dass der Halteabschnitt eine Aufnahmekammer umfasst, in der die Kolbendichtung aufgenommen ist, und die zwischen dem ersten Hülsenteil und dem zweiten Hülsenteil gebildet ist. Eine solche Aufnahmekammer gestattet eine einfache und sichere und darüber hinaus eine geschützte Halterung der Kolbendichtung.In a further development, it is proposed that the holding section comprises a receiving chamber, in which the piston seal is received, and which is formed between the first sleeve part and the second sleeve part. Such a receiving chamber allows a simple and safe and beyond a protected mounting of the piston seal.

Eine einfache Fügemethode für die beiden Hülsenteile besteht darin, dass sie miteinander verpresst sind. Im Gegensatz zu einer Schweißverbindung wird darüber hinaus ein Verzug des Anschlagelements vermieden.A simple joining method for the two sleeve parts is that they are pressed together. In contrast to a welded connection, a delay of the stop element is also avoided.

Besonders vorteilhaft ist es dabei, wenn die beiden Hülsenteile und die Kolbendichtung eine vormontierte Baugruppe bilden. Diese vormontierte Baugruppe wird nach dem Einsetzen des Kolbens in die Führungsöffnung des Gehäuses auf den Kolben als ganzes aufgeschoben, wodurch Montagezeit gespart wird. Nach dem Aufschieben dieser vormontierten Baugruppe kann die Kolbenfeder aufgesetzt und anschließend am vom Arbeitsraum abgewandten Ende des Kolbens ein Federteller, beispielsweise durch eine Pressverbindung, befestigt werden. Hierzu kann der Kolben mit seinem arbeitsraumseitigen Ende gegen die ihm gegenüberliegende Begrenzungswand des Arbeitsraumes gedrückt werden, ohne dass die Gefahr einer Beschädigung beispielsweise eines Mengensteuerventils besteht.It is particularly advantageous if the two sleeve parts and the piston seal form a preassembled module. This pre-assembled assembly is postponed after insertion of the piston in the guide opening of the housing on the piston as a whole, whereby assembly time is saved. After pushing on this preassembled module, the piston spring can be placed and then attached to the end remote from the working space of the piston, a spring plate, for example by a press connection. For this purpose, the piston can be pressed with its working space end against the opposite boundary wall of the working space without the risk of damage, for example, a quantity control valve.

Zeichnungdrawing

Nachfolgend werden besonders bevorzugte Ausführungsbeispiele der vorliegenden Erfindung unter Bezugnahme auf die beiliegende Zeichnung näher erläutert. In der Zeichnung zeigen:

Figur 1
eine schematische Darstellung eines Kraftstoffsystems einer Brennkraftmaschine mit einer als Kolbenpumpe ausgebildeten Kraftstoff-Hochdruckpumpe;
Figur 2
einen Teilschnitt durch die Kolbenpumpe von Figur 1;
Figur 3
einen Schnitt durch eine Baugruppe der Kolbenpumpe von Figur 1;
Figur 4
eine erste Prinzipdarstellung zur Erläuterung der Funktionsweise der Kolbenpumpe von Figur 1; und
Figur 5
eine zweite Prinzipdarstellung zur Erläuterung der Funktionsweise der Kolbenpumpe von Figur 1.
Hereinafter, particularly preferred embodiments of the present invention will be explained in more detail with reference to the accompanying drawings. In the drawing show:
FIG. 1
a schematic representation of a fuel system of an internal combustion engine with a designed as a piston pump high pressure fuel pump;
FIG. 2
a partial section through the piston pump of FIG. 1 ;
FIG. 3
a section through an assembly of the piston pump of FIG. 1 ;
FIG. 4
a first schematic diagram for explaining the operation of the piston pump of FIG. 1 ; and
FIG. 5
a second schematic diagram for explaining the operation of the piston pump of FIG. 1 ,

Beschreibung der AusführungsbeispieleDescription of the embodiments

Ein Kraftstoffsystem trägt in Figur 1 insgesamt das Bezugszeichen 10. Es umfasst einen Kraftstoffbehälter 12, aus dem eine Vorförderpumpe 14 den Kraftstoff zu einer als Kolbenpumpe ausgebildeten Hochdruck-Kraftstoffpumpe 16 fördert. Diese verdichtet den Kraftstoff auf einen sehr hohen Druck und fördert ihn zu einem Kraftstoffrail 18, an welches mehrere Injektoren 20 angeschlossen sind. Diese spritzen den Kraftstoff direkt in ihnen zugeordnete Brennräume 22 ein. Die Kolbenpumpe 16 wird von der Brennkraftmaschine mechanisch angetrieben, wie durch die Verbindung 24 angedeutet wird. Zur Steuerung der Fördermenge der Kolbenpumpe 16 umfasst diese einlassseitig ein Mengensteuerventil 26.A fuel system carries in FIG. 1 overall, the reference numeral 10. It comprises a fuel tank 12, from which a prefeed pump 14 conveys the fuel to a piston pump designed as a high-pressure fuel pump 16. This compresses the fuel to a very high pressure and conveys it to a fuel rail 18, to which a plurality of injectors 20 are connected. These inject the fuel directly into their associated combustion chambers 22 a. The piston pump 16 is mechanically driven by the internal combustion engine, as indicated by the connection 24. To control the Flow rate of the piston pump 16 includes this inlet side a quantity control valve 26th

Die Kolbenpumpe 16 ist in Figur 2 stärker im Detail dargestellt: Danach umfasst sie ein insgesamt in etwa zylindrisches Gehäuse 28, welches in Figur 2 nach oben hin durch einen Deckel 30 verschlossen ist. Unter dem Deckel ist, wie weiter unten noch erläutert werden wird, ein in Figur 2 nicht sichtbarer Druckdämpfer angeordnet. In Figur 2 von unten her ist in das Gehäuse 28 eine Stufenbohrung 32 eingebracht, in die eine Kolbenbuchse 34 eingesetzt ist. In letzterer ist wiederum ein Kolben 36 mit sehr geringem Spiel axial verschieblich geführt.The piston pump 16 is in FIG. 2 It is shown in more detail in detail: Thereafter, it comprises a total of approximately cylindrical housing 28, which in FIG. 2 is closed at the top by a cover 30. Under the lid, as will be explained below, an in FIG. 2 invisible pressure damper arranged. In FIG. 2 from below, a stepped bore 32 is introduced into the housing 28, into which a piston bushing 34 is inserted. In the latter, in turn, a piston 36 is guided axially displaceable with very little play.

Der Kolben 36 und das in Figur 2 obere Ende der Stufenbohrung 32 begrenzen einen Arbeitsraum 38, in den der Kraftstoff vom seitlich am Gehäuse 28 angeordneten Mengensteuerventil 26 während eines Saughubs über einen Einlass 40 gelangt. Während eines Kompressionshubs des Kolbens 36 wird der Kraftstoff aus dem Arbeitsraum 38 über einen Auslass 42 zum Kraftstoffrail 18 hin ausgestoßen.The piston 36 and the in FIG. 2 Upper end of the stepped bore 32 define a working space 38, in which the fuel from the side of the housing 28 arranged quantity control valve 26 passes through an inlet 40 during a suction stroke. During a compression stroke of the piston 36, the fuel is expelled from the working space 38 via an outlet 42 to the fuel rail 18.

Der Kolben 36 ist als Stufenkolben ausgebildet mit einem zum Arbeitsraum 38 hin gewandten Bereich 44 mit größerem Durchmesser und einem vom Arbeitsraum 38 ferngelegenen Bereich 46 mit kleinerem Durchmesser. Zwischen den beiden Bereichen 44 und 46 des Kolbens 36 ist eine ringförmige Stufe 48 vorhanden, durch die ein Absatz gebildet wird, auf den weiter unten noch stärker im Detail eingegangen werden wird. Typische Durchmesser für die Bereiche 44 und 46 sind 9 bzw. 6 mm. Wie aus Figur 2 ersichtlich ist, ist das Gehäuse 28 mit einem Anschlussstutzen 50 in eine Aufnahmeöffnung 52 in einen Motorblock 54 der Brennkraftmaschine eingesetzt. Das vom Arbeitsraum 38 abgewandte Ende des Kolbens 36 arbeitet dabei mit einem Exzenterabschnitt 56 der Antriebswelle 24 zusammen.The piston 36 is formed as a stepped piston with a working space 38 toward the area 44 of larger diameter and a remote from the working space 38 area 46 with a smaller diameter. Between the two regions 44 and 46 of the piston 36, an annular step 48 is provided through which a shoulder is formed, which will be discussed in more detail below. Typical diameters for the regions 44 and 46 are 9 and 6 mm, respectively. How out FIG. 2 it can be seen, the housing 28 is inserted with a connecting piece 50 in a receiving opening 52 in an engine block 54 of the internal combustion engine. That of the work space 38 remote end of the piston 36 cooperates with an eccentric portion 56 of the drive shaft 24 together.

Nach dem Einsetzen des Kolbens 36 in die Führungsöffnung der Kolbenbuchse 34 wird von dem vom Arbeitraum 38 abgewandten Ende des Kolbens 36 her eine in Figur 3 stärker im Detail dargestellte Baugruppe 58 am Gehäuse 28 montiert, die ein Anschlagelement 60 und eine Kolbendichtung 62 umfasst. Das Anschlagelement 60 wiederum besteht aus einem ersten Hülsenteil 64 und einem zweiten Hülsenteil 66. Beide Hülsenteile 64 und 66 sowie die Kolbendichtung 62 sind koaxial zum Kolben 36 angeordnet. Die Kolbendichtung 62 liegt in Einbaulage an der Mantelfläche des Kolbens 36 an und trennt einen kraftstoffseitigen Förderbereich 68 von einem motorölseitigen Antriebsbereich 70 (vergleiche Figur 2).After insertion of the piston 36 in the guide opening of the piston sleeve 34 from the working space 38 facing away from the end of the piston 36 is forth in FIG. 3 Assembly 58, shown in greater detail, is mounted to housing 28, which includes a stop member 60 and a piston seal 62. The stop element 60 in turn consists of a first sleeve part 64 and a second sleeve part 66. Both sleeve parts 64 and 66 and the piston seal 62 are arranged coaxially with the piston 36. The piston seal 62 rests in the installed position on the lateral surface of the piston 36 and separates a fuel-side delivery region 68 from a motor oil-side drive region 70 (cf. FIG. 2 ).

Das erste Hülsenteil 64 umfasst einen radial innenliegenden und sich rohrartig axial erstreckenden Innenabschnitt 72, einen sich radial erstreckenden Mittelabschnitt 74, der an das zum Arbeitsraum 38 bzw. zum Förderbereich 68 hin zeigende Ende des Innenabschnitts 72 angeformt ist, und einen radial außen an den Mittelabschnitt 74 angeformten Außenabschnitt 76, der sich in axialer Richtung zum Antriebsbereich 70 hin erstreckt. Das zweite Hülsenteil 66 umfasst einen ringförmigen und radial innenliegenden Innenabschnitt 78, einen radial außen an den Innenabschnitt 78 angeformten Mittelabschnitt 80, der sich in axialer Richtung zum Arbeitsraum 38 bzw. zum Förderbereich 68 hin erstreckt, und einen an den Mittelabschnitt 80 angeformten Außenabschnitt 82, der sich radial nach außen erstreckt. Der Außendurchmesser des Mittelabschnitts 80 des zweiten Hülsenteils 66 und der Innendurchmesser des Innenabschnitts 72 des ersten Hülsenteils 64 sind zumindest bereichsweise so aufeinander abgestimmt, dass der Innenabschnitt 78 und der Mittelabschnitt 80 des zweiten Hülsenteils 66 durch eine Presspassung innerhalb des ersten Hülsenteils 64 gehalten sind.The first sleeve part 64 comprises a radially inner and tubular axially extending inner portion 72, a radially extending central portion 74, which is integrally formed on the working space 38 and the conveying area 68 towards the end of the inner portion 72, and a radially outwardly to the central portion 74 formed outer portion 76 which extends in the axial direction to the drive portion 70 through. The second sleeve part 66 comprises an annular and radially inner inner portion 78, a radially outwardly formed on the inner portion 78 central portion 80 which extends in the axial direction of the working space 38 and the conveying region 68 and an integrally formed on the central portion 80 outer portion 82, which extends radially outward. The outer diameter of the central portion 80 of the second sleeve portion 66 and the inner diameter of the inner portion 72 of the first sleeve portion 64 are at least partially coordinated so that the inner portion 78 and the central portion 80 of the second sleeve portion 66 are held by a press fit within the first sleeve portion 64.

An dem vom Arbeitsraum 38 bzw. vom Förderbereich 68 abgewandten freien Ende des Innenabschnitts 72 des ersten Hülsenteils 64 ist ein kurzer nach radial einwärts gerichteter Umbug 84 vorhanden. Dieser Umbug 84 bildet zusammen mit einem Bereich des Innenabschnitts 72 des ersten Hülsenteils 64 und dem Innenabschnitt 78 des zweiten Hülsenteils 66 einen Halteabschnitt für die Kolbendichtung 62 in Form einer ringförmigen Aufnahmekammer 86.At the free end of the inner portion 72 of the first sleeve portion 64 facing away from the working space 38 and from the conveying area 68, a short, radially inwardly directed turn 84 is present. This bend 84, together with a portion of the inner portion 72 of the first sleeve portion 64 and the inner portion 78 of the second sleeve portion 66, forms a retainer portion for the piston seal 62 in the form of an annular receiving chamber 86.

Wie bereits oben angedeutet wurde, wird die Baugruppe 58 nach der Montage des Kolbens 36 auf den Bereich 46 des Kolbens 36 aufgeschoben. Die Außenseite des Außenabschnitts 76 des ersten Hülsenteils 64 wird dann in 88 eingepresst und mit dem Anschlussstutzen 50 des Gehäuses 28 verschweißt. Nun wird eine Kolbenfeder 90 montiert, deren Durchmesser so gewählt ist, dass sie sich mit einem Ende axial an dem zum Innenabschnitt 72 des ersten Hülsenteils 64 benachbarten Bereich des Mittelabschnitts 74 abstützt. Der zum Mittelabschnitt 74 benachbarte Bereich des Innenabschnitts 72 weist einen leicht vergrößerten Durchmesser auf, durch den die Kolbenfeder 90 zentriert wird, ohne dass deren freie Beweglichkeit durch den Innenabschnitt 72 insgesamt eingeschränkt wird.As already indicated above, the assembly 58 is pushed onto the region 46 of the piston 36 after the assembly of the piston 36. The outside of the outer portion 76 of the first sleeve part 64 is then pressed in 88 and welded to the connection piece 50 of the housing 28. Now, a piston spring 90 is mounted, the diameter of which is selected so that it is supported axially at one end to the inner portion 72 of the first sleeve portion 64 adjacent region of the central portion 74. The portion of the inner portion 72 adjacent to the central portion 74 has a slightly increased diameter, by which the piston spring 90 is centered without its free mobility being restricted by the inner portion 72 as a whole.

Auf das vom Arbeitsraum 38 bzw. vom Förderbereich 68 abgewandte Ende des Kolbens 36 wird nun ein als Federteller 92 ausgebildetes Stützelement aufgepresst, an dem sich das andere Ende der Kolbenfeder 90 ebenfalls axial abstützt. Beim Aufpressen des Federtellers 92 auf den Kolben 36 stützt sich dieser mit seinem dem Arbeitsraum 38 zugewandten Ende an der den Arbeitsraum 38 begrenzenden Wand des Gehäuses 28 ab. Die Kolbenfeder 90 ist somit zwischen dem Federteller 92 und dem Mittelabschnitt 74 des ersten Hülsenteils 64 gespannt.On the end facing away from the working space 38 and the delivery area 68 of the end of the piston 36 now formed as a spring plate 92 support member is pressed, on which the other end of the piston spring 90 is also axially supported. When pressing the spring plate 92 on the piston 36, this is supported with its the working space 38 facing the end of the working space 38 limiting Wall of the housing 28 from. The piston spring 90 is thus tensioned between the spring plate 92 and the central portion 74 of the first sleeve part 64.

Da der Außendurchmesser des Bereichs 44 des Kolbens 36 größer ist als der Innendurchmesser des Innenabschnitts 78 des zweiten Hülsenteils 66, kommt der Absatz 48, solange die Kolbenpumpe 16 noch nicht in die Aufnahmeöffnung 52 eingesetzt ist, in Anlage an den Innenabschnitt 78 des zweiten Hülsenteils 66. Dieser bildet also einen Anschlag für den Absatz 48 des Kolbens 36 und verhindert, dass der Kolben 36 aus der fertig montierten Kolbenpumpe 16 herausfällt, solange diese noch nicht an den Motorblock 54 der Brennkraftmaschine angebaut ist. Es versteht sich, dass nach dem Einbau der Kolbenpumpe 16 in die Aufnahmeöffnung 52 im Motorblock 54 ein Kontakt zwischen dem Anschlag 78 und dem Absatz 48 ausgeschlossen ist, wie in Figur 2 gezeigt.Since the outer diameter of the portion 44 of the piston 36 is greater than the inner diameter of the inner portion 78 of the second sleeve member 66, the shoulder 48, as long as the piston pump 16 is not yet inserted into the receiving opening 52, in abutment against the inner portion 78 of the second sleeve member 66th This thus forms a stop for the shoulder 48 of the piston 36 and prevents the piston 36 from falling out of the fully assembled piston pump 16, as long as it is not yet attached to the engine block 54 of the internal combustion engine. It is understood that after installation of the piston pump 16 in the receiving opening 52 in the engine block 54, a contact between the stopper 78 and the shoulder 48 is excluded, as in FIG. 2 shown.

Aus Figur 2 geht auch hervor, dass vom Kolben 36, dem zweiten Hülsenteil 66, sowie dem Mittelabschnitt 74 des ersten Hülsenteils 64, und dem Gehäuse 28 ein Ausgleichsraum 94 begrenzt wird, der über einen Kanal 96 mit dem Druckdämpfer (Bezugszeichen 98 in den Figuren 4 und 5) verbunden ist. Mit dem Druckdämpfer 98 ist über einen Kanal 100 ferner ein vom Arbeitsraum 38 abgelegener Bereich des Mengensteuerventils verbunden.Out FIG. 2 It is also apparent that the piston 36, the second sleeve part 66, and the central portion 74 of the first sleeve member 64, and the housing 28, a compensation chamber 94 is limited, via a channel 96 with the pressure damper (reference numeral 98 in the FIGS. 4 and 5 ) connected is. With the pressure damper 98 is further connected via a channel 100 remote from the working space 38 portion of the quantity control valve.

Die Funktion des Ausgleichsraums 94 ergibt sich aus den Figuren 4 und 5: Bei einem Saughub (Figur 4) bewegt sich der Kolben 36 in Richtung des Pfeils 102. Durch das kombinierte Einlass- und Mengensteuerventil 26 strömt Kraftstoff vom Druckdämpfer 98 sowie vom Ausgleichsraum 94 über den Kanal 96 in den Arbeitsraum 38. Hierzu ist der Druckdämpfer 98 über einen Kanal 104 an den Auslass der Vorförderpumpe 14 angeschlossen.The function of the compensation chamber 94 results from the FIGS. 4 and 5 : During a suction stroke ( FIG. 4 ) The piston 36 moves in the direction of arrow 102. Through the combined intake and quantity control valve 26, fuel flows from the pressure damper 98 and from the compensation chamber 94 via the channel 96 into the working space 38 Pressure damper 98 connected via a channel 104 to the outlet of the feed pump 14.

Während eines Kompressionshubs (Figur 5) bewegt sich der Kolben 36 in Richtung des Pfeils 106. Hierdurch wird der im Arbeitsraum 38 eingeschlossene Kraftstoff komprimiert und, bei geschlossenem Einlass-/Mengensteuerventil 26 und geöffnetem Auslassventil 108 über den Auslass 42 zum Kraftstoffrail 18 hin ausgestoßen.During a compression stroke ( FIG. 5 As a result, the fuel trapped in the working space 38 is compressed and, with the intake / quantity control valve 26 closed and the exhaust valve 108 open, discharged via the outlet 42 to the fuel rail 18.

Zur Reduzierung der Fördermenge wird noch während des Kompressionshubs das Einlass-/Mengensteuer-ventil 26 geöffnet, wodurch unter hohem Druck stehender Kraftstoff entsprechend der Pfeile 110 aus dem Arbeitsraum 38 abströmt. Eine hierdurch entstehende Druckpulsation wird zum einen durch den Druckdämpfer 98 reduziert, zum anderen wird das abströmende Kraftstoffvolumen auch durch das sich während eines Kompressionshubs vergrößernde Volumen des Ausgleichsraums 94 aufgenommen. Das entsprechende Hubvolumen im Ausgleichsraum 94 wird dabei durch die Fläche des Absatzes 48 zwischen den beiden Bereichen 44 und 46 des Kolbens 36 bestimmt. Es ist in Figur 5 durch eine strichpunktierte Linie 112 angedeutet und beträgt ungefähr 40-60% des Hubvolumens im Arbeitsraum 38 (Bezugszeichen 114 in Figur 4). Darüber hinaus wird während des Saughubs durch das sich verkleinernde Volumen des Ausgleichsraums 94 das Befüllen des Arbeitsraums 38 unterstützt. Dies führt zu einer Verbesserung der Dynamik und auch des Wirkungsgrads der Kolbenpumpe 10.To reduce the flow rate, the inlet / quantity control valve 26 is opened during the compression stroke, whereby high-pressure fuel flows out of the working space 38 in accordance with the arrows 110. A resulting pressure pulsation is reduced on the one hand by the pressure damper 98, on the other hand, the outflowing fuel volume is also absorbed by the volume of the expansion chamber 94 which increases during a compression stroke. The corresponding stroke volume in the compensation chamber 94 is determined by the area of the shoulder 48 between the two regions 44 and 46 of the piston 36. It is in FIG. 5 indicated by a dotted line 112 and is approximately 40-60% of the stroke volume in the working space 38 (reference numeral 114 in FIG FIG. 4 ). In addition, the filling of the working space 38 is supported during the suction stroke by the decreasing volume of the compensation chamber 94. This leads to an improvement of the dynamics and also of the efficiency of the piston pump 10.

Claims (14)

  1. Piston pump (16), particularly a high-pressure fuel pump for an internal combustion engine, with a casing (28) and with a piston (36) which delimits a working space (38) and has a shoulder (48) pointing away from the working space (38), characterized in that the piston (38) is introduced into the casing (28), with the working-space-side end in front, and the casing (28) has fastened to it an abutment element (60) having an abutment (78) which cooperates at least temporarily with the shoulder (48).
  2. Piston pump (16) according to Claim 1, characterized in that the shoulder is formed by a ring-shaped step (48) on the piston (36).
  3. Piston pump (16) according to Claim 2, characterized in that the ring-shaped step (48) delimits a compensating space (94) which is separated fluidically from the working space (38) and which is connected to a region, remote from the working space (38), of an inlet-side delivery-rate control valve (26).
  4. Piston pump (16) according to Claim 3, characterized in that a pressure damper (98) is arranged between the compensating space (94) and delivery-rate control valve (26).
  5. Piston pump (16) according to one of Claims 2 to 4, characterized in that the hydraulically active face of the ring-shaped step (48) is approximately half as large as the hydraulically active face, projecting into the working space (38), of the piston (36).
  6. Piston pump (16) according to one of the preceding claims, characterized in that the abutment element (60) comprises a sleeve part (66) coaxial to the piston (36) and having a radially inner region on which the abutment (78) is formed.
  7. Piston pump (16) according to one of the preceding claims, characterized in that the abutment element (60) comprises a sleeve part (64) which is coaxial to the piston (36) and which has, on a radially outer region, an axially running fastening portion (76) at which the sleeve part (64) is connected, preferably pressed in and/or welded (88), to the casing (28).
  8. Piston pump (16) according to Claim 7, characterized in that a piston spring (90) is supported on a radially extending portion (74) of the sleeve part (64), the said portion being arranged radially inwards from the axial fastening portion (76).
  9. Piston pump (16) according to one of the preceding claims, characterized in that it comprises a casing-fixed piston seal (62) which bears against a surface area of the piston (36) and which separates a delivery region (68) from a driving region (70), and in that the piston seal (62) is held by a holding portion (86) of the abutment element (60).
  10. Piston pump (16) according to Claim 9, characterized in that the abutment element (60) comprises a first sleeve part (64), which holds the piston seal (62), and a second sleeve part (66), on which the abutment (78) is present.
  11. Piston pump (16) according to Claim 10, characterized in that the holding portion comprises a reception chamber (86) in which the piston seal (62) is received and which is formed between the first sleeve part (64) and the second sleeve part (66).
  12. Piston pump (16) according to either one of Claims 10 and 11, characterized in that the two sleeve parts (64, 66) are pressed together.
  13. Piston pump (16) according to one of Claims 10 to 12, characterized in that the two sleeve parts (64, 66) and the piston seal (62) form a preassembled subunit (58).
  14. Piston pump (16) according to one of the preceding claims, characterized in that a supporting element (92) for a piston spring (90) is pressed on at that end of the piston (36) which is remote from the working space (38), and in that the piston (36) can be supported on a wall of the working space (38) while the supporting element (92) is being pressed on.
EP05797277A 2004-12-28 2005-10-05 Piston pump, particularly a high-pressure fuel pump for an internal combustion engine Active EP1834089B1 (en)

Applications Claiming Priority (2)

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DE102004063075.5A DE102004063075B4 (en) 2004-12-28 2004-12-28 High-pressure fuel pump for an internal combustion engine with a stepped piston and a quantity control valve
PCT/EP2005/055002 WO2006069818A1 (en) 2004-12-28 2005-10-05 Piston pump, particularly a high-pressure fuel pump for an internal combustion engine

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EP1834089A1 EP1834089A1 (en) 2007-09-19
EP1834089B1 true EP1834089B1 (en) 2012-12-12

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EP (1) EP1834089B1 (en)
JP (1) JP4664989B2 (en)
CN (1) CN101094988B (en)
DE (1) DE102004063075B4 (en)
ES (1) ES2395942T3 (en)
WO (1) WO2006069818A1 (en)

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US9709055B2 (en) 2008-04-25 2017-07-18 Hitachi Automotive Systems, Ltd. Mechanism for restraining fuel pressure pulsation and high pressure fuel supply pump of internal combustion engine with such mechanism

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ES2395942T3 (en) 2013-02-18
CN101094988B (en) 2010-09-29
JP2008525713A (en) 2008-07-17
DE102004063075B4 (en) 2015-11-26
CN101094988A (en) 2007-12-26
WO2006069818A1 (en) 2006-07-06
EP1834089A1 (en) 2007-09-19
DE102004063075A1 (en) 2006-07-13

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