(19)
(11)EP 3 365 550 B1

(12)EUROPEAN PATENT SPECIFICATION

(45)Mention of the grant of the patent:
11.12.2019 Bulletin 2019/50

(21)Application number: 16781473.0

(22)Date of filing:  14.10.2016
(51)International Patent Classification (IPC): 
F02M 59/10(2006.01)
F02M 59/44(2006.01)
B04B 5/00(2006.01)
F04B 53/20(2006.01)
(86)International application number:
PCT/EP2016/074741
(87)International publication number:
WO 2017/067856 (27.04.2017 Gazette  2017/17)

(54)

HYDRAULIC MACHINE WITH CENTRIFUGAL PARTICLE TRAP

HYDRAULISCHE MASCHINE MIT ZENTRIFUGALPARTIKELABSCHEIDER

MACHINE HYDRAULIQUE AYANT UN PIÈGE CENTRIFUGE À PARTICULES


(84)Designated Contracting States:
AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR

(30)Priority: 20.10.2015 GB 201518508

(43)Date of publication of application:
29.08.2018 Bulletin 2018/35

(73)Proprietor: Delphi Technologies IP Limited
St. Michael (BB)

(72)Inventors:
  • FAIRBAIRN, Matthew
    Longfield Kent DA38JG (GB)
  • GARLAND, Paul F.
    Gillingham Kent ME7 4BQ (GB)

(74)Representative: Delphi France SAS 
c/o Delphi Technologies Campus Saint Christophe Bâtiment Galilée 2 10, avenue de l'Entreprise
95863 Cergy Pontoise Cedex
95863 Cergy Pontoise Cedex (FR)


(56)References cited: : 
WO-A1-2010/127899
DE-U1-202005 020 012
US-A1- 2006 021 826
DE-A1-102005 014 680
JP-A- H07 259 684
  
      
    Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention).


    Description

    TECHNICAL FIELD



    [0001] The present invention relates to a hydraulic machine provided with a particle trap.

    BACKGROUND OF THE INVENTION



    [0002] In fuel injectors, fuel cleanliness is paramount to the successful operation of all fuel injection equipment. Failure to ensure an adequate level of filtration results in deterioration of sensitive parts of the system, including valve seats, guides in the high pressure parts of the pump, drivetrain components and injectors.

    [0003] The sources or abrasive debris are built-in or generated by wear and are in suspension from the fuel in the tank. Respectively, these are traditionally minimised by adequate washing and clean room assembly or designing to minimise wear, and providing paper-type filters as part of the system which are changed according to a maintenance schedule. Document US2006/0021826 discloses an annular filter fixed to a camshaft.

    [0004] Whilst every effort is made to minimise wear of components downstream of the inlet filter, inevitably, some debris is generated over the lifetime of a pump. This is a particular problem to pumps which include the cambox in the filling circuit. In the prior art 'twin filters' having a second paper filter element are currently used in some heavy duty FIE systems. Said twin-filters re-filter fuel after it has passed through the transfer pump, but this is not applied to pumps which fill from the cambox. The debris generated in the pump downstream of the inlet filter causes further wear.

    SUMMARY OF THE INVENTION



    [0005] Accordingly, it is an object of the present invention to resolve the above mentioned problems in providing a hydraulic machine comprising a shaft, rotating about a rotational axis and a fluid circuit for circulation of a fluid around said shaft, the fluid being, in use when the shaft is rotating, radially outwardly centrifuged.

    [0006] The hydraulic machine is further provided with a particle trap fixed to the shaft, said particle trap being arranged in the fluid circuit and being adapted to capture and retain particles flowing in the fluid.

    [0007] Particularly, the particle trap comprises a trap housing fixed to the shaft, said trap housing defining a blind hole open in the fluid circuit and outwardly extending from the opening in the fluid circuit toward a blind end.

    [0008] Also, the particle trap further comprises a retaining member arranged inside the blind hole and defining a lower chamber, between the through opening in the fluid circuit and the retaining member and, an upper chamber between the retaining member and the blind end. The retaining member is provided with an orifice so that, in use particles flowing in the fluid are outwardly centrifuged and enter the lower chamber then pass through the orifice to enter the upper chamber where they are trapped and retained.

    [0009] The retaining member is shaped having a concave side arranged toward the lower chamber and, the concave shape has a pointy tip, the through opening being arranged at said tip.

    [0010] Also, the retaining member protrudes inside the upper chamber therein creating a trap for particles.

    [0011] In an embodiment, the shaft is a composite camshaft comprising a cylindrical shaft over which is fixedly engaged a cam member. The particle trap is arranged in said cam member, the blind hole extending in the cam member and opening in the inner cylindrical face of the cam member.

    [0012] Particularly, the retaining member is fixed inside said blind hole.

    [0013] In an alternative, the retaining member is snapped in the hole.

    [0014] More precisely, in a specific application, the machine is a fuel pump provided with a cam box having a housing defining an internal volume in which rotates, in use, the composite camshaft actuating a pumping unit.

    [0015] In this pump application, the particle trap is a hole drilled in the cam member.

    BRIEF DESCRIPTION OF THE DRAWINGS



    [0016] The present invention is now described by way of example with reference to the accompanying drawings in which:

    Figure 1 is an axial section of a high pressure fuel pump provided with a particle trap.

    Figure 2 is a magnified section of the particle trap of figure 1.


    DESCRIPTION OF THE PREFERRED EMBODIMENTS



    [0017] The invention is now described in reference to a high pressure fuel pump 10 represented on figure 1 adapted to be arranged on an internal combustion engine in order to deliver high pressure fuel to fuel injectors not represented.

    [0018] The fuel pump 10 is of a cambox type and it comprises a housing 12 defining an internal volume V wherein is arranged a camshaft 14 rotating about a rotational axis A1 between bearings 16 and, a pumping unit 18 operating about a pumping axis A2 perpendicular to the rotational axis A1. The camshaft 14 is of the type known by the skilled person as a composite camshaft comprising a cylindrical shaft 15 over which is fixedly engaged a cam member 20 having an outer profiled face 22 and an inner cylindrical face 24 engaged over the shaft 15 and fixed onto it.

    [0019] The pumping unit 18 comprises a pumping head 26 having a housing 28 provided with an axial A2 bore 30 wherein is slidably arranged a plunger 32 protruding outside the pumping head housing 28 and extending toward an end provided with a cam follower 34 permanently in contact with the outer profiled face 22 of the cam. A spring 36 arranged around the plunger 32 is compressed between the head housing 28 and a spring seat 38 fixed to the plunger 32, the spring 36 generating a force permanently biasing the cam follower 34 onto the cam member 20. As it is well known, the bore 30 further defines between a blind end of the bore and an extremity of the plunger a compression chamber 40 having an inlet 42 for low pressure fuel to enter and an outlet 44 for high pressure fuel to exit.

    [0020] In use, fuel F at low pressure circulating in the internal volume V ensures lubrication of the camshaft 14 rotating between the bearings 16 and of the cam follower 34 cooperating with the cam member 20. In a lower portion LV of the internal volume V, the circulation circuit 46 within which flows said low pressure fuel F comprises a space S comprised between the end of the camshaft 14 and the housing 12, said space S being represented on the left of figure 1, the circuit 46 further comprises a first conduit 48 axially A1 drilled inside the camshaft 14, opening in said space S and extending toward an end defining a T-junction 50 wherefrom depart radial channels 52, two being represented on the figure but more could be arranged, opening in grooves 54 provided on the peripheral cylindrical face of the cylindrical shaft 15. As visible on the figure, the grooves 54 extend in the axial direction A1 below the cam member 20, the right end of the groove 54, as per the arbitrary orientation of the figure, is closed while the left extremity extends beyond the cam member 20 and enables fluid communication with an upper portion UV of the internal volume V, said fluid communication being ensured through a clearance laterally comprised between the cam member 20 and the housing 12.

    [0021] The fuel circulation circuit 46 further comprises particle traps 56, two being represented on the figure, although only one or more than two could be arranged. Said particle trap 56, visible on figure 1 and detailed on figure 2, comprises a blind hole 58 drilled in the cam member 20 and opening in the inner cylindrical face 24. As visible on figure 1, although not being mandatory for operation, the blind hole 58 is drilled at an angle of approximately 45° relative to the axes A1 or A2 in order to enable the manufacturing operation and passage of the drill. The cam member 20 is arranged on the shaft 15 so the bling hole 58 opens in a groove 54 of the circulation circuit 46. Inside the blind hole 58 is arranged a retaining member 60 so that the internal space of the blind hole is divided in a lower chamber LC, extending between the opening of the blind hole 58 in the groove 54 and the retaining member 60 and, an upper chamber UC between the retaining member 60 and the blind end of the hole 58.

    [0022] In an alternative embodiment, the particle trap 56 can be independent from the cam member 20. The trap 56 can comprise its own trap housing provided with the blind hole 58Anyway, it is important for the trap to operate to be arranged so the dense debris particles are subject to centrifuge effect so that they pass into the trap 56.

    [0023] The retaining member 60 has an ogive shape, a dome shape or a conical shape are also possible alternatives, and it is arranged in the blind hole 58 so that the lower chamber LC is concave and the upper chamber UC is convex. The wall of the retaining member is provided with a through orifice 62 arranged at the top of the ogive shape, said orifice 62 creating a permanent fluid communication between the lower LC and the upper UC chambers. In order to maintain the retaining member 60 in position in the blind hole 58, the retaining member 60 is provided on its external face with an annular crown 64 that is complementary engaged in a peripheral annular groove 66 provided on the peripheral face of the blind hole 58. Said engagement ensures the fixation of the retaining member 60 inside the hole 58. Modes of fixation alternative to the snap-in shown on the figures are possible, for instance gluing, brazing, should materials allow such process, are possible. The snap-in shown enables the retaining member 60 to be a plastic moulded part easily deformable to engage it inside the hole 58 until the crown 64 snaps, or clips, in the groove 66. It is desired that the retaining member 60 seals in the blind hole 58 reasonably well to prevent particles from 'leaking' back into the flow path when the pump is stationary.

    [0024] In operation, the camshaft 14 rotates and the fuel flows in the circulation circuit 46 from the space S and inside the first conduit 48 then, the fuel is naturally centrifuged through the radial channels 52 toward the grooves 54. The fuel F may carry undesirable particles P of higher density than the fuel. Said particles P are therefore naturally directed by centrifugal force in the blind hole 58 where the concave face of the retaining member 60 drives said particle toward the orifice 62 enabling the entry of said particle P in the upper chamber UC. Once in there, the particles are trapped and remain permanently inside said convex upper chamber UC.

    [0025] The invention has been disclosed in the context of a high pressure fuel pump but, the particle trap 56 can be successfully implemented in any hydraulic machine wherein a fluid is centrifuged in a flow circuit flows. Furthermore, although the method of filtering debris will require centrifugal motion acting on both the fluid and any particles within that fluid, it is not necessary to have a centrifugal motion to move fluid to the location of the filter. The flow of fluid to the centrifugal filter can be achieved by other methods that create a pressure difference between regions of fluid. For instance the trap 60 could be placed in a drilling between two regions of different pressure, but still relying on centrifugal force to trap particles.

    LIST OF REFERENCES



    [0026] 
    V
    internal volume to the housing
    A1
    rotational axis
    A2
    pumping axis
    S
    space
    LV
    lower portion of the internal volume
    UV
    upperportion of the internal volume
    LC
    lower chamber
    UC
    upper chamber
    F
    fuel
    10
    fuel pump - hydraulic machine
    12
    housing
    14
    camshaft
    15
    cylindrical shaft
    16
    bearings
    18
    pumping unit
    20
    cam member
    22
    outer face
    24
    inner face
    26
    pumping head
    28
    housing of the pumping head
    30
    bore
    32
    plunger
    34
    cam follower
    36
    spring
    38
    spring seat
    40
    compression chamber
    42
    inlet
    44
    outlet
    46
    circulation circuit
    48
    first conduit
    50
    T-junction
    52
    radial channels
    54
    groove
    56
    particle trap
    58
    blind hole
    60
    retaining member
    62
    orifice
    64
    crown
    66
    annular groove.



    Claims

    1. Hydraulic machine (10) comprising a shaft (14, 15) rotating about a rotational axis (A1) and a fluid circuit (46) for circulation of a fluid (F) around said shaft (14, 15), the fluid being, in use when the shaft is rotating, radially outwardly centrifuged,
    characterized in that
    the hydraulic machine (10) is further provided with a particle trap (56) fixed to the shaft (14, 15), said particle trap (56) being arranged in the fluid circuit (46) and being adapted to capture and retain particles (P) flowing in the fluid (F) and wherein,
    the particle trap (56) comprises a trap housing fixed to the shaft (14, 15), said trap housing defining a blind hole (58) open in the fluid circuit (46) and outwardly extending from the opening in the fluid circuit toward a blind end,
    the particle trap (56) further comprising a retaining member (60) arranged inside the blind hole (58) and defining a lower chamber (LC), between the through opening in the fluid circuit and the retaining member (60) and, an upper chamber (UC) between the retaining member (60) and the blind end, the retaining member (60) being provided with an orifice (62) so that, in use particles (P) flowing in the fluid (F) are outwardly centrifuged and enter the lower chamber (LC) then pass through the orifice (62) enter the upper chamber (UC) where they are trapped and retained and wherein,
    the retaining member (60) is shaped having a concave side arranged toward the lower chamber (LC) and,
    wherein said concave shape has a pointy tip, the through opening (62) being arranged at said tip.
     
    2. Hydraulic machine (10) as claimed in claim 1 wherein the retaining member (60) protrudes inside the upper chamber (UC) therein creating a trap for particles (P).
     
    3. Hydraulic machine (10) as claimed in claim 2 wherein the shaft is a composite camshaft (14) comprising a cylindrical shaft (15) over which is fixedly engaged a cam member (20), the particle trap (56) being arranged in said cam member (20), the blind hole (58) extending in the cam member (20) and opening in the inner cylindrical face (24) of the cam member (20).
     
    4. Hydraulic machine (10) as claimed in claim 3 wherein the retaining member (60) is fixed inside said blind hole (58).
     
    5. Hydraulic machine (10) as claimed in claim 4 wherein the retaining member (60) is snapped in the hole (58).
     
    6. Hydraulic machine (10) as claimed claim 5 wherein the machine is a fuel pump provided with a cam box having a housing (12) defining an internal volume (V) in which rotates, in use, the composite camshaft (14) actuating a pumping unit (18).
     
    7. Hydraulic machine (10) as claimed in claim 6 wherein the particle trap (56) is a hole drilled in the cam member (20).
     


    Ansprüche

    1. Hydraulische Maschine (10), die eine um eine Rotationsachse (A1) rotierende Welle (14, 15) und einem Fluidkreislauf (46) zur Zirkulation eines Fluids (F) um die Welle (14, 15) aufweist, wobei das Fluid, in Verwendung bei rotierender Welle, radial nach außen zentrifugiert wird,
    dadurch gekennzeichnet, dass
    die hydraulische Maschine (10) weiter mit einer an der Welle (14, 15) befestigten Partikelfalle (56) versehen ist, wobei die Partikelfalle (56) in dem Fluidkreislauf (46) angeordnet ist und ausgebildet ist, sich in dem Fluid (F) bewegende Partikel (P) einzufangen und zurückzuhalten, und wobei
    die Partikelfalle (56) ein an der Welle (14, 15) befestigtes Fallengehäuse aufweist, wobei das Fallengehäuse ein Sackloch (58) definiert, das in dem Fluidkreislauf (46) offen ist und sich von der Öffnung in dem Fluidkreislauf nach außen in Richtung eines Sackendes erstreckt,
    wobei die Partikelfalle (56) weiter ein Halteelement (60) aufweist, das in dem Sackloch (58) angeordnet ist und eine untere Kammer (LC) zwischen der Durchlassöffnung in dem Fluidkreislauf und dem Halteelement (60) und eine obere Kammer (UC) zwischen dem Halteelement (60) und dem Sackende definiert, wobei das Halteelement (60) mit einer Öffnung (62) vorgesehen ist, so dass, in Verwendung, sich in dem Fluid (F) bewegende Partikel (P) nach außen zentrifugiert werden und in die untere Kammer (LC) eintreten, dann durch die Öffnung (62) in die obere Kammer (UC) eintreten, wo sie eingefangen und zurückgehalten werden, und wobei
    das Rückhalteelement (60) geformt ist mit einer konkaven Seite angeordnet in Richtung der unteren Kammer (LC), und
    wobei die konkave Form eine spitze Spitze hat, wobei die Durchlassöffnung (62) an der Spitze angeordnet ist.
     
    2. Hydraulische Maschine (10) gemäß Anspruch 1, wobei das Halteelement (60) in die obere Kammer (UC) hineinragt, wodurch eine Falle für Partikel (P) gebildet wird.
     
    3. Hydraulische Maschine (10) gemäß Anspruch 2, wobei die Welle eine zusammengesetzte Nockenwelle (14) ist, die eine zylindrische Welle (15) aufweist, über die ein Nockenelement (20) fest in Eingriff ist, wobei die Partikelfalle (56) in dem Nockenelement (20) angeordnet ist, wobei sich das Sackloch (58) in dem Nockenelement (20) erstreckt und sich in der inneren zylindrischen Fläche (24) des Nockenelements (20) öffnet.
     
    4. Hydraulische Maschine (10) gemäß Anspruch 3, wobei das Halteelement (60) innerhalb des Sacklochs (58) befestigt ist.
     
    5. Hydraulische Maschine (10) gemäß Anspruch 4, wobei das Halteelement (60) in dem Loch (58) eingerastet ist.
     
    6. Hydraulische Maschine (10) gemäß Anspruch 5, wobei die Maschine eine Kraftstoffpumpe ist, die mit einer Nockenbox mit einem Gehäuse (12) vorgesehen ist, das ein Innenvolumen (V) definiert, in dem, in Verwendung, die zusammengesetzte Nockenwelle (14) rotiert, die eine Pumpeneinheit (18) betätigt.
     
    7. Hydraulische Maschine (10) gemäß Anspruch 6, wobei die Partikelfalle (56) ein Loch ist, das in das Nockenelement (20) gebohrt ist.
     


    Revendications

    1. Machine hydraulique (10) comprenant un arbre (14, 15) tournant autour d'un axe de rotation (A1) et un circuit de fluide (46) pour la circulation d'un fluide (F) autour dudit arbre (14, 15), le fluide étant, en utilisation, quand l'arbre est en rotation, centrifugé radialement vers l'extérieur,
    caractérisée en ce que
    la machine hydraulique (10) est dotée en outre d'un piège à particules (56) fixé à l'arbre (14, 15), ledit piège à particules (56) étant agencé dans le circuit de fluide (46) et étant adapté pour capturer et retenir des particules (P) s'écoulant dans le fluide (F), et dans laquelle
    le piège à particules (56) comprend un boîtier de piège fixé à l'arbre (14, 15), ledit boîtier de piège définissant un trou borgne (58) ouvert dans le circuit de fluide (46) et s'étendant vers l'extérieur depuis l'ouverture dans le circuit de fluide en direction d'une extrémité borgne,
    le piège à particules (56) comprenant en outre un élément de retenue (60) agencé à l'intérieur du trou borgne (58) et définissant une chambre inférieure (LC) entre l'ouverture traversante dans le circuit de fluide et l'élément de retenue (60), et une chambre supérieure (UC) entre l'élément de retenue (60) et l'extrémité borgne, l'élément de retenue (60) étant doté d'un orifice (62) de sorte que, en utilisation, des particules (P) s'écoulant dans le fluide (F) sont centrifugées vers l'extérieur et entrent dans la chambre inférieure (LC), puis passent à travers l'orifice (62), entrent dans la chambre supérieure (UC) où elles sont piégées et retenues, et dans laquelle
    l'élément de retenue (60) est formé en ayant un côté concave agencé en direction de la chambre inférieure (LC), et
    dans laquelle ladite forme concave a un embout pointu, l'ouverture traversante (62) étant agencée sur ledit embout.
     
    2. Machine hydraulique (10) selon la revendication 1, dans laquelle l'élément de retenue (60) se projette à l'intérieur de la chambre supérieure (UC), créant à l'intérieur un piège pour des particules (P).
     
    3. Machine hydraulique (10) selon la revendication 2, dans laquelle l'arbre est un arbre à came composite (14) comprenant un arbre cylindrique (15) sur lequel est engagé fixement un élément de came (20), le piège à particules (56) étant agencé dans ledit élément de came (20), le trou borgne (58) s'étendant dans l'élément de came (20) et s'ouvrant dans la face cylindrique intérieure (24) de l'élément de came (20).
     
    4. Machine hydraulique (10) selon la revendication 3, dans laquelle l'élément de retenue (60) est fixé à l'intérieur dudit trou borgne (58).
     
    5. Machine hydraulique (10) selon la revendication 4, dans laquelle l'élément de retenue (60) est enclenché dans le trou (58).
     
    6. Machine hydraulique (10) selon la revendication 5, dans laquelle la machine est une pompe à carburant dotée d'un carter à came ayant un boîtier (12) définissant un volume interne (V) dans lequel, en utilisation, l'arbre à came composite (14) tourne en actionnant une unité de pompage (18).
     
    7. Machine hydraulique (10) selon la revendication 6, dans laquelle le piège à particules (56) est un trou percé dans l'élément de came (20).
     




    Drawing











    Cited references

    REFERENCES CITED IN THE DESCRIPTION



    This list of references cited by the applicant is for the reader's convenience only. It does not form part of the European patent document. Even though great care has been taken in compiling the references, errors or omissions cannot be excluded and the EPO disclaims all liability in this regard.

    Patent documents cited in the description