WO2013098301A1 - High-pressure fuel pump for a fuel injection system - Google Patents

High-pressure fuel pump for a fuel injection system Download PDF

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Publication number
WO2013098301A1
WO2013098301A1 PCT/EP2012/076918 EP2012076918W WO2013098301A1 WO 2013098301 A1 WO2013098301 A1 WO 2013098301A1 EP 2012076918 W EP2012076918 W EP 2012076918W WO 2013098301 A1 WO2013098301 A1 WO 2013098301A1
Authority
WO
WIPO (PCT)
Prior art keywords
hollow cylinder
seal
pressure fuel
pump
pump piston
Prior art date
Application number
PCT/EP2012/076918
Other languages
German (de)
French (fr)
Inventor
Markus Schetter
Original Assignee
Robert Bosch Gmbh
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 Robert Bosch Gmbh filed Critical Robert Bosch Gmbh
Priority to EP12818522.0A priority Critical patent/EP2798210B1/en
Priority to CN201280062345.9A priority patent/CN104024635B/en
Publication of WO2013098301A1 publication Critical patent/WO2013098301A1/en
Priority to IN3227DEN2014 priority patent/IN2014DN03227A/en

Links

Classifications

    • 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
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M59/00—Pumps specially adapted for fuel-injection and not provided for in groups F02M39/00 -F02M57/00, e.g. rotary cylinder-block type of pumps
    • F02M59/02—Pumps specially adapted for fuel-injection and not provided for in groups F02M39/00 -F02M57/00, e.g. rotary cylinder-block type of pumps of reciprocating-piston or reciprocating-cylinder type
    • F02M59/10—Pumps specially adapted for fuel-injection and not provided for in groups F02M39/00 -F02M57/00, e.g. rotary cylinder-block type of pumps of reciprocating-piston or reciprocating-cylinder type characterised by the piston-drive
    • F02M59/102—Mechanical drive, e.g. tappets or cams
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M59/00—Pumps specially adapted for fuel-injection and not provided for in groups F02M39/00 -F02M57/00, e.g. rotary cylinder-block type of pumps
    • F02M59/44—Details, components parts, or accessories not provided for in, or of interest apart from, the apparatus of groups F02M59/02 - F02M59/42; Pumps having transducers, e.g. to measure displacement of pump rack or piston
    • F02M59/442—Details, components parts, or accessories not provided for in, or of interest apart from, the apparatus of groups F02M59/02 - F02M59/42; Pumps having transducers, e.g. to measure displacement of pump rack or piston means preventing fuel leakage around pump plunger, e.g. fluid barriers
    • 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
    • F04B1/0426—Arrangements for pressing the pistons against the actuated cam; Arrangements for connecting the pistons to the actuated cam
    • 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
    • F04B1/0443—Draining of the housing; Arrangements for handling leaked fluids

Definitions

  • the invention relates to a high-pressure fuel pump designed in particular as a plug-in pump for a fuel injection system for injecting fuel into the combustion chamber of an internal combustion engine having the features of the preamble of claim 1.
  • a high-pressure fuel pump designed as a plug-in pump for an internal combustion engine is disclosed, for example, in the published patent application DE 10 2008 002 195 A1. It comprises a piston which is accommodated in a hollow cylinder and has one end which projects beyond the hollow cylinder and can be displaced into a reciprocating movement by a compression spring against a radial projection of a drive shaft rotating about an axis in the hollow cylinder.
  • the hollow cylinder superior end of the piston and the hollow cylinder are liquid-tightly connected by a bellows and a from Bellows, the hollow cylinder and the pump piston enclosed annular space is connected to a leakage line, the leakage line opens directly into the annulus.
  • Bellows seals of the aforementioned type are among the contactless sealing method. They have the disadvantage that a defect leads to the immediate failure of the internal combustion engine.
  • contacting sealing methods such as rod seals and metallic seals are known, which have a leakage-resistant Form th ring gap. By tightening the exhaust gas, such leakage is no longer acceptable.
  • the present invention is therefore based on the object, a high-pressure fuel pump, in particular plug-in pump to specify, via which a permanently secure media separation is ensured.
  • the proposed high-pressure fuel pump, in particular plug-in pump, for a fuel injection system for injecting fuel into the combustion chamber of an internal combustion engine comprises a liftable pump piston whose first end is guided in a hollow cylinder and whose second end is supported indirectly via a cup-shaped component on a cam or eccentric shaft. Furthermore, the high-pressure pump comprises a preferably designed as a bellows seal, which is attached to form an annular space on the one hand on the pump piston and on the other hand on the hollow cylinder. According to the invention, a guide gap formed between the pump piston and the hollow cylinder is designed as an annular gap seal for sealing the annular space.
  • the guide gap opens into an annular groove formed in the hollow cylinder, which is connected to a leakage line for returning a leakage amount.
  • both a contactless and a contacting sealing method are used.
  • the combination of both sealing methods thus ensures a particularly secure media separation.
  • the internal combustion engine can continue to operate, since a seal is still ensured via the annular gap seal.
  • a further formed between the pump piston and the hollow cylinder and opening into the annular groove guide gap is designed as an annular gap seal.
  • the further guide gap is separated from the first guide gap via the annular groove formed in the hollow cylinder. This ensures that a leakage quantity flowing over the further guide gap into the annular groove is dissipated via the leakage line connected thereto and does not pass into the annular space enclosed by the preferably designed as a bellows seal. In this way, pressure pulsations in the annulus are avoided and consequently the annulus enclosing seal relieved.
  • the required lengths and l 2 of the two executed as annular gap seals guide column can be determined by simulation. Preferably, the length l 2 of the further guide gap is greater than the length of the first guide gap selected.
  • the seal is preferably designed as a bellows attached to an outer peripheral surface of the pump piston. In this way, the volume of the enclosed by the seal annulus is minimized. Further preferably, the attachment of the seal on the pump piston by means of a crimp ring.
  • the crimp ring allows a gas-tight connection of the seal to the pump piston. Alternatively or additionally, further fastening means may be provided.
  • the seal which is preferably designed as a bellows, is fastened to an outer peripheral surface of the hollow cylinder.
  • the fastening takes place again by means of a crimp ring, in order at the same time to effect a gas-tight connection.
  • the collar is attached radially inwardly to the hollow cylinder and extends the annular gap seal designed as a guide gap between the pump piston and the hollow cylinder.
  • the preferably designed as a bellows seal comes to lie in this way close to the pump piston, whereby the volume of the enclosed seal of the annular space on is minimized.
  • direct contact of the individual folds of the seal, which is preferably designed as a bellows, with the pump piston should be avoided in order to increase the service life of the seal.
  • the length of the preferably designed as a bellows seal is therefore to be chosen such that the opening angle of the individual folds during a stroke of the pump piston is as small as possible.
  • the seal is made of a resistant material, in particular of a plastic, such as polytetrafluoroethylene.
  • FIG. 1 shows a longitudinal section through a designed as a plug-in pump according to the invention high-pressure fuel pump
  • FIG. 2 shows a detail of FIG. 1 in the region of the guide of the pump piston
  • Fig. 3 shows a detail of Fig. 1 in the region of the attachment of the bellows seal on the hollow cylinder and
  • Fig. 4 is a perspective view of the bellows seal.
  • the plug-in pump shown in FIG. 1 comprises a pump piston 1, whose first end 1.1 is received in a hollow cylinder 2 of a cylinder head and whose second end 1.2 is supported indirectly via a cup-shaped component 3 on a camshaft 4.
  • the second end 1.2 forms a piston foot 17 on soft a spring plate 16 is placed for receiving a spring 15.
  • the spring force of the spring 15 holds the cup-shaped component 3 and the pump piston 1 in contact with the camshaft 4.
  • the spring 15 and the cup-shaped component 3 surround the hollow cylinder. 2
  • the pump piston 1 and the hollow cylinder 2 are connected to seal a guide gap 7, 10 via a seal 5 designed as a bellows.
  • the seal 5 is fastened on the one hand to an outer peripheral surface 11 of the pump piston 1 and on the other hand to an outer peripheral surface 13 of a collar 14 attached to the hollow cylinder 2.
  • the fastening takes place by means of crimp rings 12 which effect a gas-tight connection of the seal 5 to the pump piston 1 and the hollow cylinder 2.
  • the seal 5 designed as a bellows surrounds an annular space 6, in which the guide gap 7 opens.
  • the guide gap 7 terminates at an annular groove 8 formed in the hollow cylinder 2, which is connected to a leakage line 9 for the return of a leakage amount emerging via the further guide gap 10. This ensures that the leakage quantity does not get into the annular space 6 and causes pressure pulsations which would stress the seal 5.
  • the lengths and l 2 are chosen such that ⁇ l 2 .
  • the optimal lengths, which ensure a sufficient seal for media separation, can be found out by simulation.
  • the section of Fig. 3 shows the attachment of the bellows formed as a seal 5 on the collar 14 of the hollow cylinder 2 by means of a crimp ring 12.
  • At the seal 5 are for receiving the crimp rings 12 at both ends of collar portions 18 are formed (see Fig. 4), which allow application of the crimp ring 12.
  • the collar portions 18 further allow a flat application of the seal 5 on the outer peripheral surface 11 of the pump piston 1 and the outer peripheral surface 13 of the attached to the hollow cylinder 2 collar 14.
  • the position of the collar portions 18 is selected such that the convolutions of the bellows at a distance with respect to the pump piston 1 are held.
  • the volume of the annular space 6 is reduced to a minimum, in order to minimize the unwanted circulation volume at the same time.
  • the seal 5 can also be realized by a differently designed membrane seal.

Abstract

The invention relates to a high-pressure fuel pump, in particular a plug-in pump, for a fuel injection system for injecting fuel into the combustion chamber of an internal combustion engine, comprising a pump piston (1) which can carry out a stroke movement and the first end (1.1) of which is guided in a hollow cylinder (2) and the second end (1.2) is indirectly supported on a camshaft or eccentric shaft (4) via a cup-shaped component (3). The high-pressure fuel pump further comprises a seal (5) which is preferably designed as a bellows and which is fixed to the pump piston (1) at one end and to the hollow cylinder (2) at the other end, thereby forming an annular space (6). According to the invention, a guide gap (7) which is formed between the pump piston (1) and the hollow cylinder (2) is designed as an annular gap seal in order to seal the annular space (6). Furthermore, the guide gap (7) opens into an annular groove (8) which is formed in the hollow cylinder (2) and which is connected to a leakage line (9) in order to recirculate a leakage quantity.

Description

Beschreibung  description
Titel title
Kraftstoffhochdruckpumpe für ein Kraftstoffe! nspritzsystem  High-pressure fuel pump for a fuel! nspritzsystem
Die Erfindung betrifft eine insbesondere als Steckpumpe ausgestaltete Kraftstoffhochdruckpumpe für ein Kraftstoffeinspritzsystem zum Einspritzen von Kraftstoff in den Brennraum einer Brennkraftmaschine mit den Merkmalen des Oberbegriffs des Anspruchs 1. The invention relates to a high-pressure fuel pump designed in particular as a plug-in pump for a fuel injection system for injecting fuel into the combustion chamber of an internal combustion engine having the features of the preamble of claim 1.
Stand der Technik State of the art
Eine als Steckpumpe ausgeführte Kraftstoffhochdruckpumpe für eine Verbrennungskraftmaschine geht beispielsweise aus der Offenlegungsschrift DE 10 2008 002 195 A1 hervor. Sie umfasst einen in einem Hohlzylinder aufgenommenen Kolben mit einem Ende, das den Hohlzylinder überragt und durch eine Druckfeder an einen radialen Vorsprung einer um eine Achse rotierenden Antriebswelle in dem Hohlzylinder in eine hin- und hergehende Bewegung versetzbar ist. Zur Trennung der Medien Kraftstoff und Schmieröl, wobei insbesondere das Eindringen von Kraftstoff in den ölbeaufschlagten Innenraum der Verbrennungskraftmaschine verhindert werden soll, wird in dieser Druckschrift vorgeschlagen, das das den Hohlzylinder überragende Ende des Kolbens und der Hohlzylinder durch einen Faltenbalg flüssigkeitsdicht verbunden sind und ein vom Faltenbalg, dem Hohlzylinder und dem Pumpenkolben umschlossener Ringraum an eine Leckageleitung angeschlossen ist, wobei die Leckageleitung unmittelbar in den Ringraum mündet. A high-pressure fuel pump designed as a plug-in pump for an internal combustion engine is disclosed, for example, in the published patent application DE 10 2008 002 195 A1. It comprises a piston which is accommodated in a hollow cylinder and has one end which projects beyond the hollow cylinder and can be displaced into a reciprocating movement by a compression spring against a radial projection of a drive shaft rotating about an axis in the hollow cylinder. For the separation of the media fuel and lubricating oil, in particular the penetration of fuel in the ölbeaufschlagten interior of the internal combustion engine is to be prevented, is proposed in this document that the hollow cylinder superior end of the piston and the hollow cylinder are liquid-tightly connected by a bellows and a from Bellows, the hollow cylinder and the pump piston enclosed annular space is connected to a leakage line, the leakage line opens directly into the annulus.
Faltenbalg-Dichtungen der vorstehend genannten Art gehören zu den berührlosen Dichtverfahren. Sie weisen den Nachteil auf, dass ein Defekt zum sofortigen Ausfall der Verbrennungskraftmaschine führt. Bellows seals of the aforementioned type are among the contactless sealing method. They have the disadvantage that a defect leads to the immediate failure of the internal combustion engine.
Darüber hinaus sind berührende Dichtverfahren, wie beispielsweise Stangendichtungen und metallische Dichtungen bekannt, welche einen leckagebehafte- ten Ringspalt ausbilden. Mit Verschärfung der Abgasgesetzte ist eine solche Leckage nicht mehr hinnehmbar. In addition, contacting sealing methods, such as rod seals and metallic seals are known, which have a leakage-resistant Form th ring gap. By tightening the exhaust gas, such leakage is no longer acceptable.
Ausgehend von dem vorstehend genannten Stand der Technik liegt daher der vorliegenden Erfindung die Aufgabe zugrunde, eine Kraftstoffhochdruckpumpe, insbesondere Steckpumpe, anzugeben, über welche eine dauerhaft sichere Medientrennung gewährleistet ist. Based on the above-mentioned prior art, the present invention is therefore based on the object, a high-pressure fuel pump, in particular plug-in pump to specify, via which a permanently secure media separation is ensured.
Die Aufgabe wird gelöst durch eine Kraftstoffhochdruckpumpe mit den Merkmalen des Anspruchs 1. Vorteilhafte Weiterbildungen der Erfindung sind in den Unteransprüchen angegeben. The object is achieved by a high-pressure fuel pump with the features of claim 1. Advantageous developments of the invention are specified in the dependent claims.
Offenbarung der Erfindung Disclosure of the invention
Die vorgeschlagene Kraftstoffhochdruckpumpe, insbesondere Steckpumpe, für ein Kraftstoffeinspritzsystem zum Einspritzen von Kraftstoff in den Brennraum einer Brennkraftmaschine umfasst einen hubbeweglichen Pumpenkolben, dessen erstes Ende in einem Hohlzylinder geführt und dessen zweites Ende mittelbar über ein tassenförmiges Bauteil an einer Nocken- oder Exzenterwelle abgestützt ist. Ferner umfasst die Hochdruckpumpe eine vorzugsweise als Faltenbalg ausgebildete Dichtung, welche unter Ausbildung eines Ringraums einerseits am Pumpenkolben und andererseits am Hohlzylinder befestigt ist. Erfindungsgemäß ist zur Abdichtung des Ringraums ein zwischen dem Pumpenkolben und dem Hohlzylinder ausgebildeter Führungsspalt als Ringspaltdichtung ausgeführt. Ferner ist vorgesehen, dass der Führungsspalt in eine im Hohlzylinder ausgebildete Ringnut mündet, welche zur Rückführung einer Leckagemenge an eine Leckageleitung angeschlossen ist. Bei der erfindungsgemäßen Hochdruckpumpe gelangen somit sowohl ein berührloses als auch ein berührendes Dichtverfahren zur Anwendung. Die Kombination beider Dichtverfahren gewährleistet somit eine besonders sichere Medientrennung. Zugleich kann bei Ausfall eines Dichtverfahrens, insbesondere des berührlosen Dichtverfahrens mittels Faltenbalg, die Brennkraftmaschine weiter betrieben werden, da eine Dichtung weiterhin über die Ringspaltdichtung gewährleistet ist. Durch die Kombination zweier Dichtverfahren, kann zudem die Belastung der vorzugsweise als Faltenbalg ausgebildeten Dichtung reduziert werden, so dass weniger oft mit einem Ausfall zu rechnen ist. Denn die Ringspaltdichtung entkoppelt die Leckageleitung von dem Ringraum, der von der vorzugsweise als Faltenbalg ausgebildeten Dichtung um- schlössen wird, so dass die Dichtung belastende Druckpulsationen im Ringraum verringert werden. The proposed high-pressure fuel pump, in particular plug-in pump, for a fuel injection system for injecting fuel into the combustion chamber of an internal combustion engine comprises a liftable pump piston whose first end is guided in a hollow cylinder and whose second end is supported indirectly via a cup-shaped component on a cam or eccentric shaft. Furthermore, the high-pressure pump comprises a preferably designed as a bellows seal, which is attached to form an annular space on the one hand on the pump piston and on the other hand on the hollow cylinder. According to the invention, a guide gap formed between the pump piston and the hollow cylinder is designed as an annular gap seal for sealing the annular space. It is further provided that the guide gap opens into an annular groove formed in the hollow cylinder, which is connected to a leakage line for returning a leakage amount. In the case of the high-pressure pump according to the invention, therefore, both a contactless and a contacting sealing method are used. The combination of both sealing methods thus ensures a particularly secure media separation. At the same time, in case of failure of a sealing process, in particular the contactless sealing method by means of bellows, the internal combustion engine can continue to operate, since a seal is still ensured via the annular gap seal. By combining two sealing methods, it is also possible to reduce the load on the seal, which is preferably designed as a bellows, so that failure is less likely to occur. This is because the annular gap seal decouples the leakage line from the annular space, which is surrounded by the seal, which is preferably designed as a bellows. conclude, so that the seal stressful pressure pulsations are reduced in the annulus.
Bevorzugt ist ein weiterer zwischen dem Pumpenkolben und dem Hohlzylinder ausgebildeter und in die Ringnut mündender Führungsspalt als Ringspaltdichtung ausgeführt. Der weitere Führungsspalt ist von dem ersten Führungsspalt über die im Hohlzylinder ausgebildete Ringnut getrennt. Dadurch ist sichergestellt, dass eine über den weiteren Führungsspalt in die Ringnut strömende Leckagemenge über die hieran angeschlossene Leckageleitung abgeführt wird und nicht in den von der vorzugsweise als Faltenbalg ausgebildeten Dichtung umschlossenen Ringraum gelangt. Auf diese Weise werden Druckpulsationen im Ringraum vermieden und folglich die den Ringraum umschließende Dichtung entlastet. Die hierzu erforderlichen Längen und l2 der beiden als Ringspaltdichtungen ausgeführten Führungsspalte kann über Simulation bestimmt werden. Vorzugsweise ist die Länge l2 des weiteren Führungsspaltes größer als die Länge des ersten Führungsspaltes gewählt. Preferably, a further formed between the pump piston and the hollow cylinder and opening into the annular groove guide gap is designed as an annular gap seal. The further guide gap is separated from the first guide gap via the annular groove formed in the hollow cylinder. This ensures that a leakage quantity flowing over the further guide gap into the annular groove is dissipated via the leakage line connected thereto and does not pass into the annular space enclosed by the preferably designed as a bellows seal. In this way, pressure pulsations in the annulus are avoided and consequently the annulus enclosing seal relieved. The required lengths and l 2 of the two executed as annular gap seals guide column can be determined by simulation. Preferably, the length l 2 of the further guide gap is greater than the length of the first guide gap selected.
Gemäß einer bevorzugten Ausführungsform der Erfindung ist die vorzugsweise als Faltenbalg ausgeführte Dichtung an einer Außenumfangsfläche des Pumpen- kolbens befestigt. Auf diese Weise wird das Volumen des von der Dichtung umschlossenen Ringraums minimiert. Ferner bevorzugt erfolgt die Befestigung der Dichtung am Pumpenkolben mittels eines Crimprings. Der Crimpring ermöglicht eine gasdichte Anbindung der Dichtung an den Pumpenkolben. Alternativ oder ergänzend können weitere Befestigungsmittel vorgesehen sein. According to a preferred embodiment of the invention, the seal is preferably designed as a bellows attached to an outer peripheral surface of the pump piston. In this way, the volume of the enclosed by the seal annulus is minimized. Further preferably, the attachment of the seal on the pump piston by means of a crimp ring. The crimp ring allows a gas-tight connection of the seal to the pump piston. Alternatively or additionally, further fastening means may be provided.
Des Weiteren wird vorgeschlagen, dass die vorzugsweise als Faltenbalg ausgeführte Dichtung an einer Außenumfangsfläche des Hohlzylinders befestigt ist. Besonders bevorzugt erfolgt die Befestigung wiederum mittels eines Crimprings, um zugleich eine gasdichte Anbindung zu bewirken. Furthermore, it is proposed that the seal, which is preferably designed as a bellows, is fastened to an outer peripheral surface of the hollow cylinder. Particularly preferably, the fastening takes place again by means of a crimp ring, in order at the same time to effect a gas-tight connection.
Gemäß einer Weiterbildung der Erfindung ist die Außenumfangsfläche, an welcher die vorzugsweise als Faltenbalg ausgebildete Dichtung am Hohlzylinder befestigt ist, an einem an den Hohlzylinder angesetzten Kragen ausgebildet. Vorteilhafterweise ist der Kragen radial innenliegend an den Hohlzylinder angesetzt und verlängert den als Ringspaltdichtung ausgeführten Führungsspalt zwischen dem Pumpenkolben und dem Hohlzylinder. Die vorzugsweise als Faltenbalg ausgebildete Dichtung kommt auf diese Weise nah am Pumpenkolben zu liegen, wodurch das Volumen des von der Dichtung umschlossenen Ringraums weiter minimiert wird. Einen direkten Kontakt der einzelnen Faltungen der vorzugsweise als Faltenbalg ausgebildeten Dichtung mit dem Pumpenkolben gilt es jedoch zu vermeiden, um die Lebensdauer der Dichtung zu erhöhen. Die Länge der vorzugsweise als Faltenbalg ausgebildeten Dichtung ist daher derart zu wählen, dass der Öffnungswinkel der einzelnen Faltungen während einer Hubbewegung des Pumpenkolbens möglichst klein ist. According to one embodiment of the invention, the outer peripheral surface, on which the preferably designed as a bellows seal is attached to the hollow cylinder, formed on a collar attached to the hollow cylinder. Advantageously, the collar is attached radially inwardly to the hollow cylinder and extends the annular gap seal designed as a guide gap between the pump piston and the hollow cylinder. The preferably designed as a bellows seal comes to lie in this way close to the pump piston, whereby the volume of the enclosed seal of the annular space on is minimized. However, direct contact of the individual folds of the seal, which is preferably designed as a bellows, with the pump piston should be avoided in order to increase the service life of the seal. The length of the preferably designed as a bellows seal is therefore to be chosen such that the opening angle of the individual folds during a stroke of the pump piston is as small as possible.
Um die Robustheit und damit die Lebensdauer der vorzugsweise als Faltenbalg ausgebildeten Dichtung zu erhöhen, wird ferner vorgeschlagen, dass die Dichtung aus einem widerstandsfähigen Werkstoff, insbesondere aus einem Kunststoff, wie beispielsweise Polytetrafluorethylen, hergestellt ist. In order to increase the robustness and thus the life of the preferably formed as a bellows seal, it is further proposed that the seal is made of a resistant material, in particular of a plastic, such as polytetrafluoroethylene.
Eine bevorzugte Ausführungsform der Erfindung wird nachfolgend anhand der beigefügten Zeichnungen näher erläutert. Diese zeigen: A preferred embodiment of the invention will be explained in more detail with reference to the accompanying drawings. These show:
Fig. 1 einen Längsschnitt durch eine als Steckpumpe ausgeführte erfindungsgemäße Kraftstoffhochdruckpumpe, 1 shows a longitudinal section through a designed as a plug-in pump according to the invention high-pressure fuel pump,
Fig. 2 einen Ausschnitt der Fig. 1 im Bereich der Führung des Pumpenkolbens, 2 shows a detail of FIG. 1 in the region of the guide of the pump piston,
Fig. 3 einen Ausschnitt der Fig. 1 im Bereich der Befestigung der Faltenbalg- Dichtung am Hohlzylinder und Fig. 3 shows a detail of Fig. 1 in the region of the attachment of the bellows seal on the hollow cylinder and
Fig. 4 eine perspektivische Darstellung der Faltenbalg-Dichtung. Fig. 4 is a perspective view of the bellows seal.
Ausführliche Beschreibung der Zeichnungen Detailed description of the drawings
Die in der Fig. 1 dargestellte Steckpumpe umfasst einen Pumpenkolben 1 , dessen erstes Ende 1.1 in einem Hohlzylinder 2 eines Zylinderkopfes aufgenommen und dessen zweites Ende 1.2 mittelbar über ein tassenförmiges Bauteil 3 an einer Nockenwelle 4 abgestützt ist. Das zweite Ende 1.2 bildet eine Kolbenfuß 17 aus, auf weichen ein Federteller 16 zur Aufnahme einer Feder 15 aufgelegt ist. Die Federkraft der Feder 15 hält das tassenförmige Bauteil 3 und den Pumpenkolben 1 in Anlage mit der Nockenwelle 4. Die Feder 15 und das tassenförmige Bauteil 3 umgeben den Hohlzylinder 2. The plug-in pump shown in FIG. 1 comprises a pump piston 1, whose first end 1.1 is received in a hollow cylinder 2 of a cylinder head and whose second end 1.2 is supported indirectly via a cup-shaped component 3 on a camshaft 4. The second end 1.2 forms a piston foot 17 on soft a spring plate 16 is placed for receiving a spring 15. The spring force of the spring 15 holds the cup-shaped component 3 and the pump piston 1 in contact with the camshaft 4. The spring 15 and the cup-shaped component 3 surround the hollow cylinder. 2
Der Pumpenkolben 1 und der Hohlzylinder 2 sind zur Abdichtung eines Führungsspalts 7, 10 über eine als Faltenbalg ausgebildete Dichtung 5 verbunden. Die Dichtung 5 ist einerseits an einer Außenumfangsfläche 11 des Pumpenkolbens 1 und andererseits an einer Außenumfangsfläche 13 eines an den Hohlzylinder 2 angesetzten Kragens 14 befestigt. Die Befestigung erfolgt mittels Crimp- ringe 12, welche eine gasdichte Anbindung der Dichtung 5 an den Pumpenkol- ben 1 und den Hohlzylinder 2 bewirken. Die als Faltenbalg ausgebildete Dichtung 5 umschließt einen Ringraum 6, in welcher der Führungsspalt 7 mündet. Der Führungspalt 7 endet an einer im Hohlzylinder 2 ausgebildeten Ringnut 8, welche zur Rückführung einer über den weiteren Führungsspalt 10 austretende Leckagemenge an eine Leckageleitung 9 angeschlossen ist. Dadurch ist sicher- gestellt, dass die Leckagemenge nicht in den Ringraum 6 gelangt und Druckpulsationen verursacht, welche die Dichtung 5 belasten würden. The pump piston 1 and the hollow cylinder 2 are connected to seal a guide gap 7, 10 via a seal 5 designed as a bellows. The seal 5 is fastened on the one hand to an outer peripheral surface 11 of the pump piston 1 and on the other hand to an outer peripheral surface 13 of a collar 14 attached to the hollow cylinder 2. The fastening takes place by means of crimp rings 12 which effect a gas-tight connection of the seal 5 to the pump piston 1 and the hollow cylinder 2. The seal 5 designed as a bellows surrounds an annular space 6, in which the guide gap 7 opens. The guide gap 7 terminates at an annular groove 8 formed in the hollow cylinder 2, which is connected to a leakage line 9 for the return of a leakage amount emerging via the further guide gap 10. This ensures that the leakage quantity does not get into the annular space 6 and causes pressure pulsations which would stress the seal 5.
Wie dem Ausschnitt der Fig. 2 zu entnehmen ist, sind die Längen und l2 derart gewählt, dass < l2 ist. Die optimalen Längen, welche eine ausreichende Abdich- tung zur Medientrennung gewährleisten, können über Simulation herausgefunden werden. As can be seen from the section of FIG. 2, the lengths and l 2 are chosen such that <l 2 . The optimal lengths, which ensure a sufficient seal for media separation, can be found out by simulation.
Der Ausschnitt der Fig. 3 zeigt die Befestigung der als Faltenbalg ausgebildeten Dichtung 5 am Kragen 14 des Hohlzylinders 2 mittels eines Crimprings 12. An der Dichtung 5 sind zur Aufnahme der Crimpringe 12 an beiden Enden Bundbereiche 18 ausgebildet (siehe Fig. 4), welche ein Anlegen der Crimpringe 12 ermöglichen. Die Bundbereiche 18 ermöglichen ferner ein flaches Anlegen der Dichtung 5 an der Außenumfangsfläche 11 des Pumpenkolbens 1 sowie der Außenumfangsfläche 13 des am Hohlzylinder 2 angesetzten Kragens 14. Die Lage der Bundbereiche 18 ist dabei derart gewählt, dass die Faltungen des Faltenbalgs auf Abstand in Bezug auf den Pumpenkolben 1 gehalten werden. Zugleich ist das Volumen des Ringraums 6 jedoch auf ein Minimum reduziert, um zugleich das unerwünschte Umpumpvolumen zu minimieren. The section of Fig. 3 shows the attachment of the bellows formed as a seal 5 on the collar 14 of the hollow cylinder 2 by means of a crimp ring 12. At the seal 5 are for receiving the crimp rings 12 at both ends of collar portions 18 are formed (see Fig. 4), which allow application of the crimp ring 12. The collar portions 18 further allow a flat application of the seal 5 on the outer peripheral surface 11 of the pump piston 1 and the outer peripheral surface 13 of the attached to the hollow cylinder 2 collar 14. The position of the collar portions 18 is selected such that the convolutions of the bellows at a distance with respect to the pump piston 1 are held. At the same time, however, the volume of the annular space 6 is reduced to a minimum, in order to minimize the unwanted circulation volume at the same time.
Ergänzend wird darauf hingewiesen, dass anstelle der in den Fig. 1 bis 4 dargestellten Faltenbalg-Dichtung die Dichtung 5 auch durch eine anders gestaltete Membrandichtung realisiert werden kann. In addition, it should be noted that instead of the bellows seal shown in FIGS. 1 to 4, the seal 5 can also be realized by a differently designed membrane seal.

Claims

Ansprüche claims
1. Kraftstoffhochdruckpumpe, insbesondere Steckpumpe, für ein Kraftstoffeinspritzsystem zum Einspritzen von Kraftstoff in den Brennraum einer Brennkraftmaschine umfassend einen hubbeweglichen Pumpenkolben (1 ), dessen erstes Ende (1.1) in einem Hohlzylinder (2) geführt und dessen zweites Ende (1.2) mittelbar über ein tassenförmiges Bauteil (3) an einer Nocken- oder Exzenterwelle (4) abgestützt ist, ferner umfassend eine vorzugsweise als Faltenbalg ausgebildete Dichtung (5), welche unter Ausbildung eines Ringraums (6) einerseits am Pumpenkolben (1) und andererseits am Hohlzylinder (2) befestigt ist, 1. high-pressure fuel pump, in particular plug-in pump, for a fuel injection system for injecting fuel into the combustion chamber of an internal combustion engine comprising a liftable pump piston (1) whose first end (1.1) guided in a hollow cylinder (2) and the second end (1.2) indirectly via a cup-shaped component (3) on a cam or eccentric shaft (4) is supported, further comprising a preferably designed as a bellows seal (5), which forms an annular space (6) on the one hand on the pump piston (1) and on the other hand on the hollow cylinder (2) is attached,
dadurch gekennzeichnet, dass zur Abdichtung des Ringraums (6) ein zwischen dem Pumpenkolben (1) und dem Hohlzylinder (2) ausgebildeter Führungsspalt (7) als Ringspaltdichtung ausgeführt ist und der Führungsspalt (7) in eine im Hohlzylinder (2) ausgebildete Ringnut (8) mündet, welche zur Rückführung einer Leckagemenge an eine Leckageleitung (9) angeschlossen ist. characterized in that for sealing the annular space (6) between the pump piston (1) and the hollow cylinder (2) formed guide gap (7) is designed as an annular gap seal and the guide gap (7) formed in a hollow cylinder (2) annular groove (8 ), which is connected to the return of a leakage amount to a leakage line (9).
2. Kraftstoffhochdruckpumpe nach Anspruch 1 , 2. High-pressure fuel pump according to claim 1,
dadurch gekennzeichnet, dass ein weiterer zwischen dem Pumpenkolben (1) und dem Hohlzylinder (2) ausgebildeter und in die Ringnut (8) mündender Führungsspalt (10) als Ringspaltdichtung ausgeführt ist. characterized in that a further formed between the pump piston (1) and the hollow cylinder (2) and in the annular groove (8) opening out guide gap (10) is designed as an annular gap seal.
3. Kraftstoffhochdruckpumpe nach Anspruch 1 oder 2, 3. high-pressure fuel pump according to claim 1 or 2,
dadurch gekennzeichnet, dass die vorzugsweise als Faltenbalg ausgeführte Dichtung (5) an einer Außenumfangsfläche (1 1) des Pumpenkolbens (1) befestigt ist, wobei die Befestigung vorzugsweise mittels eines Crimprings (12) erfolgt. characterized in that the preferably designed as a bellows seal (5) on an outer peripheral surface (1 1) of the pump piston (1) is fixed, wherein the attachment is preferably carried out by means of a crimp ring (12).
4. Kraftstoffhochdruckpumpe nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, dass die vorzugsweise als Faltenbalg ausgeführte Dichtung (5) an einer Außenumfangsfläche (13) des Hohlzylinders (2) befestigt ist, wobei die Befestigung vorzugsweise mittels eines Crimprings (12) erfolgt. 4. High-pressure fuel pump according to one of the preceding claims, characterized in that the preferably designed as a bellows seal (5) on an outer peripheral surface (13) of the hollow cylinder (2) is fixed, wherein the fastening preferably by means of a crimp ring (12).
5. Kraftstoffhochdruckpumpe nach Anspruch 4, 5. high-pressure fuel pump according to claim 4,
dadurch gekennzeichnet, dass die Außenumfangsfläche (13) an einem an den Hohlzylinder (2) angesetzten Kragen (14) ausgebildet ist. characterized in that the outer peripheral surface (13) is formed on a collar (14) attached to the hollow cylinder (2).
6. Kraftstoffhochdruckpumpe nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, dass die vorzugsweise als Faltenbalg ausgebildete Dichtung (5) aus einem widerstandsfähigen Werkstoff, insbesondere aus einem Kunststoff, wie beispielsweise Polytetrafluorethylen, hergestellt ist. 6. High-pressure fuel pump according to one of the preceding claims, characterized in that the preferably designed as a bellows seal (5) made of a resistant material, in particular of a plastic, such as polytetrafluoroethylene, is produced.
PCT/EP2012/076918 2011-12-27 2012-12-27 High-pressure fuel pump for a fuel injection system WO2013098301A1 (en)

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EP12818522.0A EP2798210B1 (en) 2011-12-27 2012-12-27 High-pressure fuel pump for a fuel injection system
CN201280062345.9A CN104024635B (en) 2011-12-27 2012-12-27 The high pressure fuel pump of fuel injection system
IN3227DEN2014 IN2014DN03227A (en) 2011-12-27 2014-04-22

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DE102011089967A DE102011089967A1 (en) 2011-12-27 2011-12-27 High-pressure fuel pump for a fuel injection system

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EP2798210A1 (en) 2014-11-05
CN104024635B (en) 2016-09-07
DE102011089967A1 (en) 2013-06-27
EP2798210B1 (en) 2017-05-24
IN2014DN03227A (en) 2015-05-22

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