EP0205814A1 - Fuel injection pump - Google Patents

Fuel injection pump Download PDF

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Publication number
EP0205814A1
EP0205814A1 EP86105601A EP86105601A EP0205814A1 EP 0205814 A1 EP0205814 A1 EP 0205814A1 EP 86105601 A EP86105601 A EP 86105601A EP 86105601 A EP86105601 A EP 86105601A EP 0205814 A1 EP0205814 A1 EP 0205814A1
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EP
European Patent Office
Prior art keywords
pump
fuel injection
injection pump
expansion sleeve
piston
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
EP86105601A
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German (de)
French (fr)
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EP0205814B1 (en
Inventor
Wilfried Ing.(grad.) Böhringer
Franz Eheim
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Robert Bosch GmbH
Original Assignee
Robert Bosch GmbH
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Publication of EP0205814A1 publication Critical patent/EP0205814A1/en
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Publication of EP0205814B1 publication Critical patent/EP0205814B1/en
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Classifications

    • 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
    • F02M41/00—Fuel-injection apparatus with two or more injectors fed from a common pressure-source sequentially by means of a distributor
    • F02M41/08—Fuel-injection apparatus with two or more injectors fed from a common pressure-source sequentially by means of a distributor the distributor and pumping elements being combined
    • F02M41/10—Fuel-injection apparatus with two or more injectors fed from a common pressure-source sequentially by means of a distributor the distributor and pumping elements being combined pump pistons acting as the distributor
    • F02M41/12—Fuel-injection apparatus with two or more injectors fed from a common pressure-source sequentially by means of a distributor the distributor and pumping elements being combined pump pistons acting as the distributor the pistons rotating to act as the distributor
    • 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
    • F02M55/00—Fuel-injection apparatus characterised by their fuel conduits or their venting means; Arrangements of conduits between fuel tank and pump F02M37/00
    • F02M55/007—Venting means
    • 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
    • F02M59/48—Assembling; Disassembling; Replacing
    • F02M59/485—Means for fixing delivery valve casing and barrel to each other or to pump casing

Definitions

  • the invention relates to a fuel injection pump according to the preamble of the main claim.
  • a fuel injection pump of this type DE-OS 24 50 5211
  • a pressure valve is arranged above the pump work chamber coaxially with the pump piston. so that a seal is created.
  • This known fuel injection pump has a disproportionately large, harmful space, the pump working space itself being able to be vented only by loosening the cap or via one of the pressure lines leading to the engine cylinders.
  • the fuel injection pump must be vented when it is started up or when the fuel tank has been pumped empty.
  • a large harmful space is disadvantageous primarily because the fuel is compressed at the high injection pressures due to its compressibility, and control errors result for the quantity control in accordance with the harmful space.
  • a harmful space can lead to the formation of cavities during the suction stroke with gas or air inclusions, which entail the risk of cavitation and / or errors when starting the spray.
  • the fuel injection pump according to the invention with the characterizing features of the main claim has the advantage that the expansion sleeve is sealingly clamped between the part receiving the pump piston and the stopper, whereby the central opening of the stopper is filled by the venting plug so that no harmful space is created here .
  • several pressure valves are provided here, each of which is arranged in front of the pressure lines after the distributor control by the pump piston.
  • the venting of the pump work space can advantageously be carried out very simply in the embodiment according to the invention by unscrewing the vent plug, when screwing it in, the plug, which is advantageously bolt-shaped, is immersed directly in the fuel located in the central plug opening after venting.
  • the stopper consists in two parts of an external threaded ring and a threaded bushing coaxially soldered into its stepped inner bore, which receives the venting stopper, the expansion sleeve being supported on the axial annular surface formed by the step.
  • This configuration has advantages in terms of manufacturing technology in particular, since the two-part design allows the axial ring surface, which also serves as a seal, to be machined well before the threaded bushing is soldered in. In this way, the end face of the expansion sleeve faces a well-machined support surface, as required for the high-pressure seal.
  • the distance from the pump piston to the internal thread of the threaded bushing is smaller than the ring surface according to a further embodiment of the invention.
  • the contact surface between the external threaded ring and the threaded bushing used for the soldering can be relatively small for sufficient durability and tightness.
  • the outwardly facing end face of the threaded bushing can advantageously serve as an axial sealing face of an annular seal clamped in by the head of the vent plug. This sealing surface can also be machined here before the two parts are soldered.
  • the bore receiving the pump piston is arranged in a cylinder sleeve, the expansion sleeve being tensioned by the stopper on the end face of the cylinder sleeve facing it.
  • the expansion sleeve advantageously forms part of the pump working space limitation while advantageously saving additional sealing points.
  • the front ends of the expansion sleeve have at least one bevel forming a cutting edge, in order to thereby achieve the highest possible Hertzian pressures at the sealing points and thus a better seal.
  • This seal can be improved by choosing different materials and / or different remuneration.
  • FIG. 1 shows a partial longitudinal section through a distributor injection pump
  • FIG. 2 shows a section from FIG. 1 on an enlarged scale.
  • a cylinder liner 2 is arranged, in the inner bore 3 of which a pump and distributor piston 4 operates.
  • the pump and distributor piston 4 is set in a reciprocating and at the same time rotating movement by a cam drive 5, including one with the pumping piston rotatably connected cam disc 6 is used, which runs on rollers 7 of a roller ring 8.
  • the rotary movement is generated by a drive shaft 9 which is also mounted in the pump housing 1 and which is coupled to the pump and distributor piston 4 via a dog clutch 10.
  • a control slide 11 On the shaft of the pump and distributor piston 4, a control slide 11 is arranged axially displaceable, the axial position of which is determined by a control lever 12 of a speed controller, not shown.
  • a relief channel 12 of a pump work chamber 13 is opened sooner or later, depending on the axial position of the control slide 11, so that the fuel quantity dependent on the axial position of the control slide 11 and delivered to the opening of the relief channel 12 is injected.
  • the pump working space 13 is delimited by the end face 17 of the pumping and distributing piston 4, by the wall of the bore 3 of the bushing 2 and by a screw connection 18, which is shown on an enlarged scale in FIG.
  • the suction channel 20 is additionally controlled by a solenoid valve 21.
  • the injection pump shown works as follows: During the suction stroke of the pump and distributor piston 4 caused by the cam drive 5, fuel is conveyed through the suction channel 20 from the interior of the housing serving as suction chamber 22 via a longitudinal groove 19 into the pump working chamber 13. The suction chamber 22 is under a slight positive pressure for this. As soon as the movement of the pump and distributor piston 4 is then reversed, fuel is pumped from the pump working space 13 via the central bore 14 to the distributor bore 15 and from there via one of the pressure channels 16 to the internal combustion engine.
  • the screw connection 18, as can be seen in FIG. 2, consists of a stopper 23 which consists of two parts, namely an external threaded ring 24 and a threaded bush 25 soldered into it.
  • a vent plug 26 is screwed into the threaded bushing 25, which takes up almost the entire inner bore of the threaded bushing 25 and presses with its head 27 an annular seal 28 onto the outwardly facing end face of the threaded bushing 25.
  • the threaded bushing 25 has a step 29 with which it connects to a step 30 the inner bore of the ring 24 abuts.
  • This ring surface 30 also serves as a support for an expansion sleeve 31, which is supported on the other hand on the cylinder liner 2.
  • the cylinder liner 2 is in turn secured by a ring 32, which is supported on the housing 1, against axial displacement in the direction of the pump piston drive.
  • a seal 33 is also arranged between the outer threaded ring 24 and the housing 1.
  • the pump working space is metallically sealed from the outside by this screw connection 18, by the expansion sleeve 31 being connected to the cylinder bushing 2 and the soldered-in threaded bushing 25 being connected to this inwards.
  • the vent plug 26 also delimits the pump work space 13 with its lower end face 34. In order to achieve high Hertzian pressures on the end sealing surfaces of the expansion sleeve 31, these end faces are each chamfered to form a cutting edge.
  • the vent plug 26 is unscrewed from the threaded bush 25, so that the space that is freed up can be filled with fuel. Then the bolt-shaped sealing plug 26 is immersed in this fuel and screwed into the threaded bushing 25, so that no air or gases remain in the pump working space 13.
  • the thread overlap is longer than the partially soldered contact section between the external threaded ring 24 and the threaded bush 25.

Abstract

Kraftstoffeinspritzpumpe für Brennkraftmaschinen, die mindestens einen Pumpenarbeitsraum (13) aufweist, der einerseits durch die Stirnfläche (17) des Pumpenkolbens (4) und die Wand (3) der Zylinderbuchse (2) und andererseits durch eine Verschlußverschraubung (18) begrenzt ist, wobei die Verschlußverschraubung aus einem einen Verschlußstopfen (26) aufnehmenden Stopfen (23) besteht, durch den eine Dehnhülse (31) auf die Zylinderbuchse (2) spannbar ist und wobei vorzugsweise der Stopfen (23) aus einem Außengewindering (24) und eine in diesen eingelötete Innengewindebuchse (25) besteht.Fuel injection pump for internal combustion engines, which has at least one pump work chamber (13) which is limited on the one hand by the end face (17) of the pump piston (4) and the wall (3) of the cylinder liner (2) and on the other hand by a screw connection (18), the Closure fitting consists of a stopper (23) receiving a stopper (26) through which an expansion sleeve (31) can be tensioned onto the cylinder liner (2) and preferably the stopper (23) consists of an external threaded ring (24) and an internal threaded bushing soldered into it (25) exists.

Description

Stand der TechnikState of the art

Die Erfindung geht aus von einer Kraftstoffeinspritzpumpe nach der Gattung des Hauptanspruchs. Bei einer bekannten Kraftstoffeinspritzpumpe dieser Art (DE-OS 24 50 521) ist achsgleich mit dem Pumpenkolben ein Druckventil oberhalb des Pumpenarbeitsraumes angeordnet, dessen Schließfeder innerhalb einer topfförmige.. Dehnhülse angeordnet ist, die durch eine als Verschlußverschraubung dienende Kappe auf einen Ventilträger gespannt ist, so daß ein Dichtverbund entsteht. Diese bekannte Kraftstoffeinspritzpumpe weist einen unverhältnismäßig großen schädlichen Raum auf, wobei der Pumpenarbeitsraum selbst nur durch Lockern der Kappe oder über eine der zu den Motorzylindern führenden Druckleitungen entlüftbar ist. Bekanntlich muß eine Kraftstoffeinspritzpumpe bei Inbetriebnahme oder auch, wenn der Kraftstofftank einmal leergepumpt worden war, entlüftet werden. Ein großer schädlicher Raum ist vor allem deshalb nachteilig, weil der Kraftstoff bei den hohen Einspritzdrücken auf Grund seiner Kompressibilität zusammengepreßt wird, wobei sich für die Mengensteuerung entsprechend dem schädlichen Raum Steuerfehler ergeben. Außerdem kann ein schädlicher Raum zu Hohlraumbildung während des Saughubes führen mit Gas- oder Lufteinschlüssen, die die Gefahr einer Kavitation und/oder Fehler beim Spritzbeginn mit sich bringen.The invention relates to a fuel injection pump according to the preamble of the main claim. In a known fuel injection pump of this type (DE-OS 24 50 521), a pressure valve is arranged above the pump work chamber coaxially with the pump piston. so that a seal is created. This known fuel injection pump has a disproportionately large, harmful space, the pump working space itself being able to be vented only by loosening the cap or via one of the pressure lines leading to the engine cylinders. As is well known, one must The fuel injection pump must be vented when it is started up or when the fuel tank has been pumped empty. A large harmful space is disadvantageous primarily because the fuel is compressed at the high injection pressures due to its compressibility, and control errors result for the quantity control in accordance with the harmful space. In addition, a harmful space can lead to the formation of cavities during the suction stroke with gas or air inclusions, which entail the risk of cavitation and / or errors when starting the spray.

Vorteile der ErfindungAdvantages of the invention

Die erfindungsgemäße Kraftstoffeinspritzpumpe mit den kennzeichnenden Merkmalen des Hauptanspruchs hat demgegenüber den Vorteil, daß die Dehnhülse dichtend zwischen dem den Pumpenkolben aufnehmenden Teil und dem Stopfen dichtend eingespannt ist, wobei durch den Entlüftungsstopfen die zentrale Öffnung des Stopfens so ausgefüllt wird, daß hier kein schädlicher Raum entsteht. Im Gegensatz zu der oben genannten bekannten Kraftstoffeinspritzpumpe sind hier mehrere Druckventile vorgesehen, die jeweils nach der Verteilersteuerung durch den Pumpenkolben vor den Druckleitungen angeordnet sind. Die Entlüftung des Pumpenarbeitsraumes kann vorteilhafterweise bei der erfindungsgemäßen Ausführung sehr einfach durch Herausschrauben des Entlüftungsstopfens erfolgen, bei dessen Hereinschrauben der vorteilhafterweise bolzenförmig ausgeführte Stopfen direkt in den nach Entlüften in der zentralen Stopfenöffnung befindlichen Kraftstoff taucht.The fuel injection pump according to the invention with the characterizing features of the main claim has the advantage that the expansion sleeve is sealingly clamped between the part receiving the pump piston and the stopper, whereby the central opening of the stopper is filled by the venting plug so that no harmful space is created here . In contrast to the known fuel injection pump mentioned above, several pressure valves are provided here, each of which is arranged in front of the pressure lines after the distributor control by the pump piston. The venting of the pump work space can advantageously be carried out very simply in the embodiment according to the invention by unscrewing the vent plug, when screwing it in, the plug, which is advantageously bolt-shaped, is immersed directly in the fuel located in the central plug opening after venting.

Nach einer vorteilhaften Ausgestaltung der Erfindung besteht der Stopfen zweiteilig aus einem Außengewindering und einem in dessen stufenförmige Innenbohrung koaxial eingelöteten, den Entlüftungsstopfen aufnehmenden Gewindebuchse, wobei sich die Dehnhülse an der durch die Stufe gebildeten axialen Ringfläche abstützt. Diese Ausgestaltung hat vor allem fertigungstechnische Vorteile, da durch die zweiteilige Ausführung die axiale Ringfläche, die auch der Dichtung dient, gut bearbeitet werden kann, bevor die Gewindebuchse eingelötet wird. Auf diese Weise liegt der Stirnseite der Dehnhülse eine, wie für die Hochdruckdichtung erforderlich, gut bearbeitete Auflagerfläche gegenüber.According to an advantageous embodiment of the invention, the stopper consists in two parts of an external threaded ring and a threaded bushing coaxially soldered into its stepped inner bore, which receives the venting stopper, the expansion sleeve being supported on the axial annular surface formed by the step. This configuration has advantages in terms of manufacturing technology in particular, since the two-part design allows the axial ring surface, which also serves as a seal, to be machined well before the threaded bushing is soldered in. In this way, the end face of the expansion sleeve faces a well-machined support surface, as required for the high-pressure seal.

Um andererseits für den Entlüftungsstopfen ausreichend Gewindegänge zur Verfügung zu haben, ist nach einer weiteren Ausgestaltung der Erfindung der Abstand vom Pumpenkolben bis zum Innengewinde der Gewindebuchse kleiner als zur Ringfläche. Die für die Lötung dienende Berührungsfläche zwischen Außengewindering und Gewindebuchse kann für eine ausreichende Haltbarkeit und Dichtheit verhältnismäßig klein sein. Vorteilhafterweise kann die nach außen gewendete Stirnfläche der Gewindebuchse als axiale Dichtfläche einer vom Kopf des Entlüftungsstopfens eingespannten Ringdichtung dienen. Auch hier kann diese Dichtfläche vor der Verlötung der beiden Teile bearbeitet werden.On the other hand, in order to have sufficient threads available for the ventilation plug, the distance from the pump piston to the internal thread of the threaded bushing is smaller than the ring surface according to a further embodiment of the invention. The contact surface between the external threaded ring and the threaded bushing used for the soldering can be relatively small for sufficient durability and tightness. The outwardly facing end face of the threaded bushing can advantageously serve as an axial sealing face of an annular seal clamped in by the head of the vent plug. This sealing surface can also be machined here before the two parts are soldered.

Nach einer weiteren Ausgestaltung der Erfindung ist die den Pumpenkolben aufnehmende Bohrung in einer Zylinderbuchse angeordnet, wobei die Dehnhülse durch den Stopfen auf die ihr zugewandte Stirnseite der Zylinderbuchse gespannt ist. Hierdurch bildet vorteilhafterweise die Dehnhülse einen Teil der Pumpenarbeitsraumbegrenzung unter vorteilhafter Einsparung zusätzlicher Dichtstellen.According to a further embodiment of the invention, the bore receiving the pump piston is arranged in a cylinder sleeve, the expansion sleeve being tensioned by the stopper on the end face of the cylinder sleeve facing it. As a result, the expansion sleeve advantageously forms part of the pump working space limitation while advantageously saving additional sealing points.

Die Stirnenden der Dehnhülse weisen nach einer zusätzlichen Ausgestaltung der Erfindung mindestens eine eine Schneide bildende Abschrägung auf, um dadurch möglichst hohe Hertz'sche Pressungen an den Dichtstellen und damit eine bessere Abdichtung zu erzielen. Diese Abdichtung kann durch die Wahl unterschiedlicher Materialien und/oder unterschiedlicher Vergütung verbessert werden.According to an additional embodiment of the invention, the front ends of the expansion sleeve have at least one bevel forming a cutting edge, in order to thereby achieve the highest possible Hertzian pressures at the sealing points and thus a better seal. This seal can be improved by choosing different materials and / or different remuneration.

Weitere Vorteile und vorteilhafte Ausgestaltungen der Erfindung sind der nachfolgenden Beschreibung, der Zeichnung und den Ansprüchen entnehmbar.Further advantages and advantageous embodiments of the invention can be found in the following description, the drawing and the claims.

Zeichnungdrawing

Ein Ausführungsbeispiel des Gegenstandes der Erfindung ist in der Zeichnung dargestellt und wird im folgenden näher beschrieben. Es zeigen: Fig. 1 einen Teillängsschnitt durch eine Verteilereinspritzpumpe und Fig. 2 einen Ausschnitt aus Fig. l in vergrößertem Maßstab.An embodiment of the object of the invention is shown in the drawing and will be described in more detail below. 1 shows a partial longitudinal section through a distributor injection pump, and FIG. 2 shows a section from FIG. 1 on an enlarged scale.

Beschreibung des AusführungsbeispielsDescription of the embodiment

In einem Gehäuse 1 einer Verteilereinspritzpumpe ist eine Zylinderbuchse 2 angeordnet, in dessen Innenbohrung 3 ein Pumpen- und Verteilerkolben 4 arbeitet.In a housing 1 of a distributor injection pump, a cylinder liner 2 is arranged, in the inner bore 3 of which a pump and distributor piston 4 operates.

Der Pumpen- und Verteilerkolben 4 wird durch einen Nockenantrieb 5 in eine hin- und hergehende und gleichzeitig rotierende Bewegung versetzt, wozu eine mit dem Pumpenkolben drehschlüssig verbundene Nockenscheibe 6 dient, die auf Rollen 7 eines Rollenringes 8 abläuft. Die Drehbewegung wird durch eine ebenfalls im Pumpengehäuse 1 gelagerte Antriebswelle 9 erzeugt, die über eine Klauenkupplung 10 mit dem Pump- und Verteilerkolben 4 gekoppelt ist.The pump and distributor piston 4 is set in a reciprocating and at the same time rotating movement by a cam drive 5, including one with the pumping piston rotatably connected cam disc 6 is used, which runs on rollers 7 of a roller ring 8. The rotary movement is generated by a drive shaft 9 which is also mounted in the pump housing 1 and which is coupled to the pump and distributor piston 4 via a dog clutch 10.

Auf dem Schaft des Pump- und Verteilerkolbens 4 ist ein Regelschieber 11 axial verschiebbar angeordnet, dessen axiale Lage über einen Regelhebel 12 eines nicht näher dargestellten Drehzahlreglers bestimmt wird. Durch den Regelschieber 11 wird ein Entlastungskanal 12 eines Pumpenarbeitsraumes 13 je nach axialer Lage des Regelschiebers 11 früher oder später aufgesteuert, so daß jeweils die von der axialen Lage des Regelschiebers 11 abhängende, bis zur Aufsteuerung des Entlastungskanals 12 geförderte Kraftstoffmenge zur Einspritzung gelangt. Von einer im Pumpenkolben verlaufenden zentralen Bohrung 14, von der auch der Entlastungskanal 12 abzweigt, zweigt eine Verteilerbohrung 15 ab, die während einer Umdrehung des Pump- und Verteilerkolbens 4 nacheinander mit in der Buchse 2 und im Gehäuse 1 verlaufenden Druckleitungen 16 verbunden wird, deren Anzahl der Zahl der Zylinder der Brennkraftmaschine entspricht. In diesen Druckleitungen 16 sind nicht näher dargestellt Druckventile angeordnet.On the shaft of the pump and distributor piston 4, a control slide 11 is arranged axially displaceable, the axial position of which is determined by a control lever 12 of a speed controller, not shown. By means of the control slide 11, a relief channel 12 of a pump work chamber 13 is opened sooner or later, depending on the axial position of the control slide 11, so that the fuel quantity dependent on the axial position of the control slide 11 and delivered to the opening of the relief channel 12 is injected. From a central bore 14 running in the pump piston, from which the relief duct 12 also branches off, branches off a distributor bore 15, which is connected in succession to pressure lines 16 running in the bushing 2 and in the housing 1 during one revolution of the pump and distributor piston 4, the pressure lines 16 of the latter Number of cylinders corresponds to the internal combustion engine. Pressure valves, not shown, are arranged in these pressure lines 16.

Der Pumpenarbeitsraum 13 wird durch die Stirnseite 17 des Pump- und Verteilerkolbens 4, durch die Wand der Bohrung 3 der Buchse 2 und durch eine Verschlußverschraubung 18 begrenzt, die in Fig.2 in vergrößertem Maßstab dargestellt ist. In den Pumpenarbeitsraum 13 münden zur Stirnseite 17 hin Längsnuten 19, deren Anzahl der Zahl der Druckleitungen 16 entspricht und die einen in der Buchse 2 und im Gehäuse 1 verlaufenden Saugkanal 20 steuern. Der Saugkanal 20 wird zusätzlich durch ein Magnetventil 21 gesteuert.The pump working space 13 is delimited by the end face 17 of the pumping and distributing piston 4, by the wall of the bore 3 of the bushing 2 and by a screw connection 18, which is shown on an enlarged scale in FIG. In the pump working space 13 open to the end face 17 longitudinal grooves 19, the number of which corresponds to the number of pressure lines 16 and one in the socket 2 and Control housing 1 running suction channel 20. The suction channel 20 is additionally controlled by a solenoid valve 21.

Die dargestellte Einspritzpumpe arbeitet wie folgt: Während des durch den Nockenantrieb 5 bewirkten Saughubes des Pump- und Verteilerkolbens 4 wird durch den Saugkanal 20 aus dem als Saugraum 22 dienenden Innenraum des Gehäuses Kraftstoff über jeweils eine Längsnut 19 in den Pumpenarbeitsraum 13 gefördert. Der Saugraum 22 steht hierfür unter einem geringen Überdruck. Sobald dann die Bewegung des Pump- und Verteilerkolbens 4 umgekehrt wird, wird aus dem Pumpenarabeitsraum 13 Kraftstoff über die zentrale Bohrung 14 zur Verteilerbohrung 15 und von dort über einen der Druckkanäle 16 zur Brennkraftmaschine gefördert. Sobald nach Zurücklegung eines bestimmten Hubes der Entlastungskanal 12 durch den Regelschieber 11 aufgesteuert wird, wird diese unter Hochdruck stattfindende Förderung zur Brennkraftmaschine unterbrochen, indem der noch im Pumpenarbeitsraum 13 befindliche Kraftstoff unter niederem Druck zurück in den Saugraum 22 strömt. Ein Abstellen der Pumpe kann durch Schließen des Saugkanals 20 mittels des Magnetventils 21 erfolgen. Die zur Brennkraftmaschine geförderte Menge wird über den Drehzahlregler geändert, indem der Regelschieber 11 verschoben wird.The injection pump shown works as follows: During the suction stroke of the pump and distributor piston 4 caused by the cam drive 5, fuel is conveyed through the suction channel 20 from the interior of the housing serving as suction chamber 22 via a longitudinal groove 19 into the pump working chamber 13. The suction chamber 22 is under a slight positive pressure for this. As soon as the movement of the pump and distributor piston 4 is then reversed, fuel is pumped from the pump working space 13 via the central bore 14 to the distributor bore 15 and from there via one of the pressure channels 16 to the internal combustion engine. As soon as the relief channel 12 is opened by the regulating slide 11 after a certain stroke has been covered, this delivery to the internal combustion engine, which takes place under high pressure, is interrupted by the fuel, which is still in the pump working chamber 13, flowing back into the suction chamber 22 under low pressure. The pump can be switched off by closing the suction channel 20 by means of the solenoid valve 21. The quantity delivered to the internal combustion engine is changed via the speed controller by moving the control slide 11.

Die Verschlußverschraubung 18 besteht, wie Fig.2 entnehmbar ist, aus einem Stopfen 23, der zweiteilig, nämlich aus einem Außengewindering 24 und einer in diesen eingelöteten Gewindebuchse 25 besteht. In die Gewindebuchse 25 ist ein Entlüftungsstopfen 26 geschraubt, der nahezu die gesamte Innenbohrung der Gewindebuchse 25 einnimmt und mit seinem Kopf 27 eine Ringdichtung 28 auf die nach außen weisende Stirnfläche der Gewindebuchse 25 preßt. Die Gewindebuchse 25 weist eine Stufe 29 auf, mit der sie an eine Stufe 30 der Innenbohrung des Ringes 24 stößt. Diese Ringfläche 30 dient gleichzeitig als Auflager für eine Dehnhülse 31, die sich andererseits an der Zylinderbuchse 2 abstützt. Die Zylinderbuchse 2 wiederum ist durch einen Ring 32, der sich am Gehäuse 1 abstützt, gegen axiales Verschieben in Richtung Pumpenkolbenantrieb gesichert. Zwischen Außengewindering 24 und Gehäuse 1 ist außerdem eine Dichtung 33 angeordnet.The screw connection 18, as can be seen in FIG. 2, consists of a stopper 23 which consists of two parts, namely an external threaded ring 24 and a threaded bush 25 soldered into it. A vent plug 26 is screwed into the threaded bushing 25, which takes up almost the entire inner bore of the threaded bushing 25 and presses with its head 27 an annular seal 28 onto the outwardly facing end face of the threaded bushing 25. The threaded bushing 25 has a step 29 with which it connects to a step 30 the inner bore of the ring 24 abuts. This ring surface 30 also serves as a support for an expansion sleeve 31, which is supported on the other hand on the cylinder liner 2. The cylinder liner 2 is in turn secured by a ring 32, which is supported on the housing 1, against axial displacement in the direction of the pump piston drive. A seal 33 is also arranged between the outer threaded ring 24 and the housing 1.

Der Pumpenarbeitsraum ist nach außen durch diese Verschlußverschraubung 18 metallisch abgedichtet, indem sich an die Zylinderbuchse 2 die Dehnhülse 31 und an diese nach innen die eingelötete Gewindebuchse 25 anschließt. Auch der Entlüftungsstopfen 26 begrenzt mit seiner unteren Stirnseite 34 den Pumpenarbeitsraum 13. Um hohe Hertz'sche Pressungen an den stirnseitigen Dichtflächen der Dehnhülse 31 zu erreichen, sind diese Stirnseiten jeweils eine Schneidkante bildend abgeschrägt.The pump working space is metallically sealed from the outside by this screw connection 18, by the expansion sleeve 31 being connected to the cylinder bushing 2 and the soldered-in threaded bushing 25 being connected to this inwards. The vent plug 26 also delimits the pump work space 13 with its lower end face 34. In order to achieve high Hertzian pressures on the end sealing surfaces of the expansion sleeve 31, these end faces are each chamfered to form a cutting edge.

Zum Entlüften des Pumpenarbeitsraumes 13 wird der Entlüftungsstopfen 26 aus der Gewindebuchse 25 herausgeschraubt, so daß der freiwerdende Raum mit Kraftstoff auffüllbar ist. Danach wird in diesen Kraftstoff der bolzenförmige Verschlußstopfen 26 eingetaucht und in die Gewindebuchse 25 eingeschraubt, so daß keine Luft oder Gase im Pumpeharbeitsraum 13 verbleiben. Um eine ausreichende Gewindeüberdeckung zwischen Verschlußstopfen 26 und Gewinde der Gewindebuchse 25 zu erzielen und um andererseits die Dehnhülse 31 zur Erzielung einer ausreichenden elastischen Verformbarkeit lang genug zu machen, ist die Gewindeüberdeckung länger als der teilweise gelötete Berührungsabschnitt zwischen Außengewindering 24 und Gewindebuchse 25.To vent the pump work space 13, the vent plug 26 is unscrewed from the threaded bush 25, so that the space that is freed up can be filled with fuel. Then the bolt-shaped sealing plug 26 is immersed in this fuel and screwed into the threaded bushing 25, so that no air or gases remain in the pump working space 13. In order to achieve a sufficient thread overlap between the sealing plug 26 and the thread of the threaded bush 25 and on the other hand to make the expansion sleeve 31 long enough to achieve sufficient elastic deformability, the thread overlap is longer than the partially soldered contact section between the external threaded ring 24 and the threaded bush 25.

Claims (6)

1. Kraftstoffeinspritzpumpe für Brennkraftmaschinen mit mindestens einem Pumpenarbeitsraum, welcher durch die Stirnseite eines Pumpenkolbens, die Innenwand einer den Pumpenkolben aufnehmenden Bohrung und eine mit einem Außengewinde in eine Gewindebohrung des Pumpengehäuses schraubbare, nach außen verschließende und eine Dehnhülse aufnehmende Verschraubung begrenzt ist, dadurch gekennzeichnet, daß die Verschraubung (18) einen das Außengewinde tragenden Stopfen (23) aufweist, in den koaxial ein Entlüftungsstopfen (26, 27) schraubbar ist und mit dem die Dehnhülse (31) den Pumpenarbeitsraum (13) abdichtend stirnseitig auf die den Pumpenkolben (4) aufnehmende Bohrung (3) aufweisende Teil (2) gespannt ist.1. A fuel injection pump for internal combustion engines with at least one pump working space, which is limited by the end face of a pump piston, the inner wall of a bore receiving the pump piston, and a screw connection that can be screwed with an external thread into a threaded bore of the pump housing, closes to the outside, and receives an expansion sleeve, characterized in that that the screw connection (18) has a plug (23) carrying the external thread, into which a vent plug (26, 27) can be screwed coaxially and with which the expansion sleeve (31) seals the pump working chamber (13) on the end face onto the pump piston (4) receiving bore (3) having part (2) is clamped. 2. Kraftstoffeinspritzpumpe nach Anspruch 1, dadurch gekennzeichnet, daß der Stopfen (23) zweiteilig aus einem Außengewindering (24) und einer in dessen stufenförmigen Innenbohrung koaxial eingelöteten und den Entlüftungsstopfen (26, 27) aufnehmenden Gewindebuchse (25) besteht, und daß sich die Dehnhülse (25) an der durch die Stufe gebildeten axialen Ringfläche (30) abstützt.2. Fuel injection pump according to claim 1, characterized in that the plug (23) in two parts from an external threaded ring (24) and one in its stepped inner bore coaxially soldered and the vent plug (26, 27) receiving threaded bush (25), and that the Expansion sleeve (25) is supported on the axial annular surface (30) formed by the step. 3. Kraftstoffeinspritzpumpe nach Anspruch 2 oder 3, dadurch gekennzeichnet, daß der Abstand von dem kolbenführenden Teil (2) bis zum Innengewinde der Gewindebuchse (25) kleiner ist als der zur Ringfläche (30).3. Fuel injection pump according to claim 2 or 3, characterized in that the distance from the piston-guiding part (2) to the internal thread of the threaded bushing (25) is smaller than that to the annular surface (30). 4. Kraftstoffeinspritzpumpe nach Anspruch 2 oder 3, dadurch gekennzeichnet, daß die nach außen gerichtete Stirnfläche der Gewindebuchse (25) als axiale Auflage einer von einem Kopf (27) des Entlüftungsstopfens (26) eingespannten Ringdichtung (28) dient.4. Fuel injection pump according to claim 2 or 3, characterized in that the outwardly directed end face of the threaded bushing (25) serves as an axial support of a ring seal (28) clamped by a head (27) of the vent plug (26). 5. Kraftstoffeinspritzpumpe nach einem der Ansprüche 1 bis 4, dadurch gekennzeichnet, daß die den Pumpenkolben (4) aufnehmende Bohrung (3) in einer Zylinderbuchse (2) angeordnet ist und daß die Dehnhülse (31) durch den Stopfen (23) auf die ihr zugewandte Stirnseite der Zylinderbuchse (2) gespannt ist.5. Fuel injection pump according to one of claims 1 to 4, characterized in that the pump piston (4) receiving bore (3) is arranged in a cylinder liner (2) and that the expansion sleeve (31) through the plug (23) on it facing end of the cylinder liner (2) is tensioned. 6. Kraftstoffeinspritzpumpe nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, daß die Stirnenden der Dehnhülse (31) mindestens eine eine Schneide bildende Abschrägung aufweisen.6. Fuel injection pump according to one of the preceding claims, characterized in that the front ends of the expansion sleeve (31) have at least one bevel forming a cutting edge.
EP86105601A 1985-05-15 1986-04-23 Fuel injection pump Expired EP0205814B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE19853517521 DE3517521A1 (en) 1985-05-15 1985-05-15 FUEL INJECTION PUMP
DE3517521 1985-05-15

Publications (2)

Publication Number Publication Date
EP0205814A1 true EP0205814A1 (en) 1986-12-30
EP0205814B1 EP0205814B1 (en) 1988-09-28

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Application Number Title Priority Date Filing Date
EP86105601A Expired EP0205814B1 (en) 1985-05-15 1986-04-23 Fuel injection pump

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US (1) US4702680A (en)
EP (1) EP0205814B1 (en)
JP (1) JPS61261652A (en)
DE (2) DE3517521A1 (en)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB9610785D0 (en) * 1996-05-23 1996-07-31 Lucas Ind Plc Radial piston pump
JP3906775B2 (en) * 2001-12-18 2007-04-18 株式会社デンソー Distributed fuel injection pump

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE882157C (en) * 1950-06-18 1953-07-06 Rudolf Dipl-Ing Schenk Venting device on fuel injection pumps
GB2057589A (en) * 1979-09-07 1981-04-01 Bosch Gmbh Robert A Distributor Type Fuel Injection Pump for an Internal Combustion Engine
DE3018791A1 (en) * 1980-05-16 1981-11-26 Robert Bosch Gmbh, 7000 Stuttgart Fuel injection pump for IC engine - has adjustment for max. fuel setting by axial cylinder displacement

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Publication number Priority date Publication date Assignee Title
US1955383A (en) * 1932-12-01 1934-04-17 Hermann John Frederick Injection pump for internal combustion engines
US2593550A (en) * 1946-03-28 1952-04-22 Fodor Nicholas Multiple unit fuel injection pump
US2784040A (en) * 1953-07-15 1957-03-05 Cornelius R Head Retaining devices for pump liners
GB819858A (en) * 1957-04-17 1959-09-09 Bosch Gmbh Robert Improvements in or relating to fuel injection equipment
DE1109955B (en) * 1960-02-24 1961-06-29 Bosch Gmbh Robert Fuel injection pump on an internal combustion engine
CH401334A (en) * 1962-04-24 1965-10-31 Burckhardt Ag Maschf Piston machine for high pressure with device for automatic pressing of the valve head
AT271997B (en) * 1965-12-24 1969-06-25 Bosch Gmbh Robert Method for changing the delivery characteristics of fuel injection pumps and fuel injection pumps for carrying out this method
US3446427A (en) * 1966-07-23 1969-05-27 Leonid Fedorovich Vereschagin High-pressure plunger-type fluid compressors
DE2450521C2 (en) * 1974-10-24 1982-04-22 Robert Bosch Gmbh, 7000 Stuttgart Fuel distributor injection pump for internal combustion engines
DE3136689A1 (en) * 1981-09-16 1983-03-24 Robert Bosch Gmbh, 7000 Stuttgart FUEL INJECTION PUMP FOR INTERNAL COMBUSTION ENGINES

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE882157C (en) * 1950-06-18 1953-07-06 Rudolf Dipl-Ing Schenk Venting device on fuel injection pumps
GB2057589A (en) * 1979-09-07 1981-04-01 Bosch Gmbh Robert A Distributor Type Fuel Injection Pump for an Internal Combustion Engine
DE3018791A1 (en) * 1980-05-16 1981-11-26 Robert Bosch Gmbh, 7000 Stuttgart Fuel injection pump for IC engine - has adjustment for max. fuel setting by axial cylinder displacement

Also Published As

Publication number Publication date
DE3517521A1 (en) 1986-11-20
US4702680A (en) 1987-10-27
DE3660829D1 (en) 1988-11-03
EP0205814B1 (en) 1988-09-28
JPS61261652A (en) 1986-11-19

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