U.S. patent application number 10/682900 was filed with the patent office on 2004-07-15 for high-pressure pump, in particular for a common-rail injection system.
This patent application is currently assigned to CRT COMMON RAIL TECHNOLOGIES AG. Invention is credited to Ganser, Marco, Kolb, Roland, Schwarz, Volker, Spinnler, Fritz.
Application Number | 20040136837 10/682900 |
Document ID | / |
Family ID | 32034716 |
Filed Date | 2004-07-15 |
United States Patent
Application |
20040136837 |
Kind Code |
A1 |
Ganser, Marco ; et
al. |
July 15, 2004 |
High-pressure pump, in particular for a common-rail injection
system
Abstract
A high-pressure pump having a plurality of individual feed pumps
is described, the feed pumps being designed as modular pump units
and being able to be lined up next to one another via their
housings, which are provided with fluid-connecting channels. At
least one line module being provided which can be coupled at least
on one side to a housing of a modular pump unit and in which the
fluid-connecting channels of the respectively adjacent housings
form intake and discharge channels which, on the one hand, lead on
further and/or, on the other hand, lead outward.
Inventors: |
Ganser, Marco; (Zurich,
CH) ; Kolb, Roland; (Regensdorf, CH) ;
Schwarz, Volker; (Zell, CH) ; Spinnler, Fritz;
(Mellingen, CH) |
Correspondence
Address: |
OBLON, SPIVAK, MCCLELLAND, MAIER & NEUSTADT, P.C.
1940 DUKE STREET
ALEXANDRIA
VA
22314
US
|
Assignee: |
CRT COMMON RAIL TECHNOLOGIES
AG
NEUHAUSEN AM RHEINFALL
CH
|
Family ID: |
32034716 |
Appl. No.: |
10/682900 |
Filed: |
October 14, 2003 |
Current U.S.
Class: |
417/273 ;
417/539 |
Current CPC
Class: |
F02M 63/0225 20130101;
F04B 1/0538 20130101; F02M 63/0001 20130101; F04B 23/06 20130101;
F02M 59/06 20130101; F02M 59/08 20130101 |
Class at
Publication: |
417/273 ;
417/539 |
International
Class: |
F04B 001/04 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 14, 2002 |
CH |
2002 1702/02 |
Claims
1. A high-pressure pump, in particular for a common-rail injection
system for internal combustion engines, having a plurality of feed
pumps which each comprises at least one plunger guided in a bore
leading into a feed space, and are driven via a common drive shaft
having eccentric sections assigned to the respective plungers, and
each feed space is connected via a pressure-controlled inlet valve
to a low-pressure supply line and via a pressure-controlled outlet
valve to a high-pressure output line, wherein the individual feed
pumps are designed as modular pump units and can be lined up next
to one another via their housings, which are provided with
fluid-connecting channels, and wherein at least one line module is
provided which can be coupled at least on one side to a housing of
a modular unit and in which the fluid-connecting channels of the
respectively adjacent housings form intake and discharge channels
which, on the one hand, lead on further and/or, on the other hand,
lead outward.
2. The high-pressure pump as claimed in claim 1, wherein the
plunger bore accommodating the plunger and the feed space are
formed in a high-pressure part screwed to the housing.
3. The high-pressure pump as claimed in claim 1 or 2, wherein each
modular pump unit in each case comprises at least two plungers
which lie diametrically opposite each other and are actuated by the
same eccentric section together with an associated feed space and
common housing.
4. The high-pressure pump as claimed in claim 1, wherein each
plunger is guided in the housing via a cup tappet and is
prestressed against the associated eccentric section by means of a
restoring spring.
5. The high-pressure pump as claimed claim 1, wherein the drive
shaft is mounted at least in the outer end walls of the housings
which are placed on the end side of a row of modules.
6. The high-pressure pump as claimed in claim 5, wherein, instead
of the drive shaft being mounted at both ends in a respective
housing end wall, it is mounted at one end in a line module forming
one end of the housing and is mounted at the other end in a housing
end wall.
7. The high-pressure pump as claimed in claim 1, wherein a bearing
socket for the drive shaft is formed in each case in line modules
which are arranged between adjacent housings.
8. The high-pressure pump as claimed in claim 7, wherein the
diameter of the bearing socket is at least slightly larger than
double the value of the largest radius of the eccentric sections of
the drive shaft.
9. The high-pressure pump as claimed in claim 1, wherein a
forced-oil supply into the bearings of the drive shaft, of the
rolling rings or sliding shoes and preferably into annular
lubricating channels of the cup tappets is provided via an end
piece fitted onto a housing end wall or line module provided on the
end side.
10. The high-pressure pump as claimed in claim 9, wherein the
forced-oil supply to the bearings takes place via bores in the
drive shaft and to the annular lubricating channels via channels in
the housings and line modules.
11. The high-pressure pump as claimed in claim 1, wherein the
channels, which are provided in the housings of the pump units and
in the line modules, are mutually orientated in the axial direction
of the high-pressure pump and are sealed at the transition points,
are provided for the low-pressure supply and for the high-pressure
removal of diesel oil, for the removal of leakage of a mixture of
diesel oil and lubricating oil, for the forced-oil supply and for
the oil return line.
12. The high-pressure pump as claimed in claim 1, having a
plurality of plungers which are moved to and fro via a common drive
shaft provided with eccentric sections, are guided in each case in
a plunger bore leading into a feed space and are actuated by an
eccentric section counter to the action of a restoring spring ,
wherein an annular collecting space for overflow lubricating oil
and overflow diesel oil is formed on the feed-space side in the
wall of the plunger bore and is connected via channels to a
diesel-oil tank.
13. The high-pressure pump as claimed in claim 1, having a
plurality of plungers which are moved to an fro via a common drive
shaft provided with eccentric sections, are guided in each case in
a plunger bore leading into a feed space and are actuated by an
eccentric section counter to the action of a storing spring in
particular via a cup tappet which is guided in a bore in the
housing, wherein, firstly, an eccentric space through which the
drive shaft passes and, secondly, at least one annular lubricating
channel which surrounds the respective plunger or cup tappet and is
formed in the housing are connected to a lubricating-oil pressure
supply, and wherein an annular spaceconnected to a lubricating-oil
return flow is provided in the region of that section of the
plunger or of the cup tappet which is on the feed-space side.
14. The high-pressure pump as claimed in claim 12 or 13, wherein a
pressure-maintaining valve is arranged in a channel section which
is common to all of the channels conducting a mixture of
lubricating- and diesel-oil leakages.
15. The high-pressure pump as claimed in claim 14, wherein the
pressure-maintaining valve can be set or controlled.
16. The high-pressure pump as claimed in one claim 1, having a
plurality of plungers which are moved to an fro via a common drive
shaft provided with eccentric sections, are guided in each case
through a plunger bore leading into a feed space and are actuated
by an eccentric section counter to the action of a restoring spring
with the interconnection of rolling elements, wherein sliding shoes
which are of two-part design are provided as the rolling
elements.
17. The high-pressure pump as claimed in claim 16, wherein the
sliding-shoe halves which can be screwed to each other have planar
bearing surfaces on the plunger side for the respective plunger or
for a cup tappet assigned to the plunger.
18. The high-pressure pump as claimed in claim 16 or 17, wherein a
sliding bearing or ball bearing is provided between the respective
eccentric section and the associated sliding shoe.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The invention relates to a high-pressure pump for a
common-rail injection system for internal combustion engines.
[0003] 2. Discussion of the Background
[0004] Common-rail injection systems are used in internal
combustion engines, in which, in order to optimize the combustion
power, the fuel is to be present in the combustion chambers of the
individual cylinders in a finely atomized form. For this purpose,
the fuel is compressed in a high-pressure pump and is distributed
to the injectors of the individual cylinders via a rail. Finally,
the process of injecting the fuel into the combustion chambers is
triggered via an electric signal, the fuel, which is under high
pressure, being finely distributed at high speed in the combustion
chambers of the engine via the injection nozzles of the
injectors.
[0005] A high-pressure pump of the type specified at the beginning
which is suitable for common-rail injection systems for diesel
engines is disclosed in EP-A-0 881 380. High-pressure pumps of this
type which, as a rule, have a plurality of piston/cylinder feed
elements make it possible to achieve high feed pressures with the
required operational reliability, these main pumps having to be
adapted in their design in a specific manner to the particular
intended use, i.e. having to be constructed especially in each
case.
[0006] Also known are high-performance diesel engines which are
provided with a classical injection system, each cylinder in this
system being assigned a pump feed element. A plurality of injection
pumps is therefore generally necessary for high-performance diesel
engines with a high number of cylinders. For example, in the case
of a V-16 cylinder engine, two in-line injection pumps each having
eight pump feed elements one behind another are arranged between
the two cylinder banks. If an engine of this type is to be provided
with a common-rail diesel injection system, a high-pressure pump
which is specially adapted in terms of power and in terms of
overall size and to the given spatial conditions is required for
this.
[0007] U.S. Pat. No. 4,184,817 discloses a multicylinder
high-pressure plunger pump, the plunger being sealed by means of
two spaced apart lip seals. The seal on the feed-space side is
lubricated by means of diesel oil and is intended at the same time
to ensure that diesel oil does not pass into a space placed between
these two lip seals and on the eccentric-drive side. An annular
chamber which is connected via channels to a diesel induction
chamber is furthermore connected upstream of this lip seal. The
lower, second lip seal, i.e. the one placed on the eccentric-drive
side, is used for sealing off the plunger against the lubricating
oil present in the eccentric drive. Labyrinth-like elements are
provided between the two lip seals and trap small, remaining
overflow amounts of diesel and lubricating oil in the space which
is placed between the two lip seals and is connected via a bore to
the surroundings.
SUMMARY OF THE INVENTION
[0008] The object of the present invention is, especially, to
provide a high-pressure pump which ensures high feed pressures,
which can be realized in a particularly economic manner, and high
operational reliability and can be adapted individually and without
any problems to the requirements present in the individual case and
also satisfies the exacting requirements placed on the service
life.
[0009] This object is achieved essentially by a high-pressure pump
having the features according to patent claim 1.
[0010] The modular manner of constructing the pump units and the
combination options with specially designed line modules enable
high-pressure pumps to be realized without any problems and in a
space-saving manner, it being possible for said pumps to be adapted
in the best possible manner to the requirements present in each
case as a function of the particular combination of modules. Using
this combination of modules and by appropriate design of the
channels, optimum guides can also be achieved for the low-pressure
supply and the high-pressure removal of fuel, in particular diesel
oil, for the removal of leakages and for lubricating-oil supplies
and oil return lines.
[0011] Each modular pump unit preferably in each case comprises at
least two plungers which lie diametrically opposite each other and
are actuated by the same eccentric section, together with an
associated feed space and common housing, the feed space and
plunger bore preferably being formed in a high-pressure part which
can be screwed to the housing.
[0012] The line module or the plurality of line modules which may
be present can be largely freely arranged within the overall
construction of the particular high-pressure pump, with the result
that, for example in the individual case, the connecting points can
be positioned in an optimum position.
[0013] According to one preferred embodiment, line modules can
simultaneously be configured with a bearing for the drive shaft,
specifically either if a line module of this type is arranged
between pump modules or if a line module of this type forms the end
of a high-pressure pump constructed from individual modules.
[0014] According to the invention, a high-pressure pump, which is
of modular construction particularly in the described manner, can
be provided with a plurality of plungers which are moved to and fro
via a common drive shaft provided with eccentric sections, are
guided in each case in the plunger bore leading into a feed space
and are actuated by an eccentric section counter to the action of a
restoring spring in particular via a cup tappet guided in a bore in
the housing, in which case, firstly, an eccentric space through
which the drive shaft passes and, secondly, at least one annular
lubricating channel which surrounds the respective plunger or cup
tappet and is formed in the housing are connected to a
lubricating-oil pressure supply, and an annular space which is
connected to a lubricating-oil return flow is provided in the
region of that section of the plunger or cup tappet which is on the
feed-space side, and in which case, furthermore, an annular
collecting space for overflow lubricating oil and overflow diesel
oil is formed on the feed-space side in the wall of the plunger
bore and is connected via channels to a diesel-oil tank, in
particular.
[0015] A refinement of a high-pressure pump in such a way results,
firstly, in a desired increase in the service life and, secondly,
in the fact that virtually no diesel oil passes into that space of
the eccentric drive which is filled with lubricating oil, and,
conversely, that also virtually no lubricating oil mixes with the
diesel oil, which mixture would sooner or later pass via the
injection nozzles into the combustion chambers of the engine and
would have a negative effect on the exhaust-gas emission of the
engine.
[0016] The separation of diesel oil and lubricating oil is obtained
in a simple manner and not prone to faults.
[0017] A further aspect which is essential for the invention and
can be used in general in high-pressure pumps of this type resides
in the fact that, instead of rolling rings which are conventionally
provided between an eccentric drive and the plunger or cup tappet
thereof which is to be actuated, use is made of sliding shoes of
two-part design. This configuration of rolling elements in the form
of two-part sliding shoes results especially in making installation
easier and also permits installation of rolling elements of this
type even if this is no longer possible using conventional rolling
rings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] Further particularly advantageous refinements of the
invention and features which are significant to the invention are
specified in the dependent claims and will also be explained in the
following description of exemplary embodiments with reference to
the drawings, in which:
[0019] FIG. 1 shows a schematic illustration of a pump unit with a
common rail, the pump unit being illustrated in accordance with a
section along the line I-I of FIG. 2,
[0020] FIG. 2 shows an axial longitudinal section through a
high-pressure pump which is of modular construction according to
the invention,
[0021] FIG. 3 shows an illustration of part of a high-pressure pump
according to the invention with a centrally arranged line module
(partially illustrated) and assigned diesel-oil tank and
lubricating-oil tank,
[0022] FIG. 4 shows a schematic sectional illustration of a pump
unit corresponding to a section along the line V-V of FIG. 2 in
order to explain the profile of the low-pressure diesel intake
line,
[0023] FIG. 5 shows an embodiment of a high-pressure pump according
to the invention that is extended in comparison to the
high-pressure pump shown in FIG. 2,
[0024] FIG. 6 shows an illustration of a refinement of a
high-pressure pump according to the invention that is reduced in
comparison to the embodiment according to FIG. 2, and
[0025] FIG. 7 shows a schematic illustration of a pump unit with
rolling elements which are designed in the form of sliding
shoes.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0026] FIG. 1 shows, in the form of a schematic illustration, a
pump unit 2 (illustrated in section) of a high-pressure pump which
is constructed from pump units of this type and from line modules 1
which have yet to be explained in detail, for a common-rail
injection system for internal combustion engines. The storage
volume 6' of a common rail 6 that is fed via a high-pressure output
line 26 is respectively connected in a known manner via
high-pressure connecting lines 4 to injectors 5.
[0027] The pump unit 2, which is shown in cross section, comprises
two plunger units which are arranged diametrically opposite each
other and are in each case formed by a plunger 14 which is guided
in a reciprocating manner in a bore 37 and is assigned a cup tappet
36 which is guided in the housing 22. The plunger 14 with its cup
tappet 36 is prestressed against an eccentric drive 10, 11 via a
restoring spring 50. The plunger bore 37 leads into a feed space 18
which is connected via a pressure-controlled inlet valve 25 to a
low-pressure supply line 24 and via a pressure-controlled outlet
valve 27 to the high-pressure output line 26. The low-pressure
supply line 24 is connected to a diesel-oil tank 33 having
ventilating means 57, specifically via an intake line 23 which
leads to a low-pressure pre-feed pump 21. A flow-regulating element
3 is arranged in the low-pressure supply line 24 for diesel
oil.
[0028] The plunger bore 37, the feed space 18 and the accommodating
regions for the valves 25 and 27 are formed in a high-pressure part
7 which is screwed to the housing 22.
[0029] The plunger 14 or the cup tappet 36 is driven via a drive
shaft 9, the center of rotation of which is indicated by 63. The
eccentric section acting on the cup tappet 36 bears the reference
number 10. A rolling ring 11 is situated in a conventional manner
between the eccentric section 10 and cup tappet 36, the sliding
bearing 12 or a ball bearing being provided between the rolling
ring 11 and eccentric element 10. The eccentric center is referred
to by the letter E and the maximum eccentricity is indicated by
H/2.
[0030] In the region separating the high-pressure part 7 and the
housing 22, an annular space 34' (which has yet to be explained in
detail) is widened in such a manner that it ensures the passage of
the high-pressure bore 26 in such a manner that should an overflow
occur at the separating point of the high-pressure bore, the
overflow quantity which arises can entirely escape into the space
34'.
[0031] The central-symmetrical design of the pump unit 2 which has
already been discussed is clarified by FIG. 1 and it thus suffices
to describe the upper part of this pump unit, since the same
applies to the lower part of the pump unit. The measures undertaken
for lubrication and for separating lubricating oil and diesel oil
will be explained in detail with reference to the following
figures.
[0032] The axial sectional illustration according to FIG. 2 shows a
high-pressure pump which is constructed in a modular manner in
accordance with the invention and has modular pump units 2 and a
line module 1, which is arranged centrally in this case. All in
all, there is therefore an arrangement of eight plungers which are
combined to form a pump, and this arrangement is advantageous
especially because it permits the construction of a narrow, tall
pump similar to a classical in-line injection pump. This enables a
pump according to the invention to be accommodated without any
problem in a structural space which is already present, for example
between the cylinder banks of a V-engine.
[0033] The lubrications which are effective in the individual pump
units and the means of guiding the lubricating oil, diesel oil and
leakages are explained with reference to the pump unit 2 (which is
illustrated at the left end in FIG. 2) by way of representation for
all of the pump units.
[0034] An annular space 45 arranged above the cup tappet 36 is
connected via a forced-oil line 31, which extends through the
entire construction of the high-pressure pump, to a lubricating-oil
tank 40 (illustrated in FIG. 3), the lubricating oil being supplied
at the required pressure via a feed pump 19. This feed pump 19 is
used to supply the bearings of the drive shaft 9 (eccentric shaft)
in the same manner with lubricating oil, specifically via the axial
lubricating-oil channel 30 and the radial bores 46. Overflow oil
from the bearings of the drive shaft 9 passes into the eccentric
space 58.
[0035] The feed pump 19 can be the lubricating-oil pump of the
engine. In this case, the lubricating-oil tank 40 is at the same
time the engine lubricating-oil tank.
[0036] In the region of movement of the open end of the cup tappet
36, a further annular space 41' is provided which leads via an
axially parallel channel 41 to a channel section 41", which runs
perpendicularly outward thereto in the line module 1. Instead of
the channel 41, openings could also be manufactured in the lower
region of the cup tappet 36. In this case, overflow oil from the
upper side of the cup tappet 36 would pass from the space 41'
through the inner empty space of the cup tappet 36 via the openings
into the eccentric space 58.
[0037] An annular collecting and mixing space 35 is formed on the
inner wall of the plunger bore 37 in the high-pressure part 7 and
is connected via a channel 60 to an annular space 34' which is
connected via a channel 34, formed in the housing 22, to the
channel 34" which is perpendicular thereto, is formed in the line
module 1 and is guided outward. An O-ring seal seals off the
annular space 41' from the annular space 34'.
[0038] The effect achieved by this refinement is that, firstly, the
cup tappet 36 is reliably and satisfactorily lubricated and,
secondly, it is ensured that no lubricating oil can pass into the
annular space 34' and consequently into the feed space 18.
[0039] In addition to the two channel sections 34" and 41",
channels for the low-pressure supply line 24 (FIG. 1) for diesel
oil and for a high-pressure output line 26" are also formed in the
line module 1. The channel 24" which is assigned to the
low-pressure supply line cannot be seen in the illustration
according FIG. 2, but is illustrated by dashed lines in FIG. 1.
[0040] The lubricating-oil flow which is guided via the channels 31
and conducted to the annular space 45 passes during operation into
the annular space 41' and from there via the channels 41 and 41"
back to the oil tank 40, which may also be the oil sump of an
engine provided with the high-pressure pump.
[0041] Both lubricating-oil leakages, via the extremely small gap
between plunger 14 and plunger bore 37, and diesel-oil leakages can
pass into the annular space 35, so that there is a corresponding
leakage mixture in this annular space 35, said mixture being
removed from the high-pressure pump via the channel 60, the space
34' and the channels 34 and 34". This mixture of overflow diesel
oil and overflow lubricating oil can be conducted back into the
diesel tank 33 shown in FIG. 3. The percentage amount of overflow
lubricating oil in the overflow diesel oil can be kept very small,
preferably smaller than 1% and, in certain places, even only 2%.
The amount of overflow lubricating oil passing into the diesel tank
33 is further diluted therein and then passes into the feed space
18, into the injection system and is finally injected into the
engine combustion chamber. The exhaust-gas quality is not
negatively affected by this small amount of oil in the injected
fuel. The overflow lubricating-oil amount is a priori small because
the gap between the plunger 14 and plunger bore 37 is extremely
small. Furthermore, the viscosity of the diesel oil is
substantially lower than that of lubricating oil and, in addition,
the pressure in the feed space 18 during the feed stroke is up to
1000 times higher than the lubricating-oil pressure. Both facts in
themselves already bring about a dominance of the overflow diesel
oil over the overflow lubricating oil. A further favorable
refinement in order to keep the overflow lubricating-oil amount
very small will be described in greater detail in conjunction with
FIG. 3.
[0042] In the same manner as the high-pressure parts 7 are sealed
off with respect to the housing 22 by high-pressure sealing
elements 8, corresponding high-pressure sealing elements 8' are
also provided between the particular housing 22 and the adjoining
line module 1. Further sealing elements (for example O-rings) are
used as low-pressure seals for the bores 31, 34 and 41. In this
manner, a leakproof, cohesive line system is provided by the bores,
such as 24, 26, 31, 34 and 41, provided in the housing 22, said
system being connected to the corresponding lines or channels 24",
26", 34", 41" in the line modules 1, it being possible for the line
modules 1 to be designed in such a manner that they have pure
lead-through channels and/or also channels leading outward.
Furthermore, the central bearing 59 of the drive shaft 9 is formed
in the line module 1, this bearing being dimensioned in such a
manner and being of such a size that the drive shaft 9 together
with the eccentric sections 10 can be pushed through it for
installation purposes.
[0043] At one end of the high-pressure pump, the end piece 15, in
which pressurized supply channels 30, 31 for the lubricating oil
are provided, is fitted in a sealing manner onto the outer end wall
13 of the housing.
[0044] The illustration according to FIG. 3 shows, in conjunction
with the high-pressure pump which has already been explained with
reference to FIG. 2, the associated diesel-oil tank 33 with feed
pump 21 and associated front pipe and the lubricating-oil tank 40
which is ventilated in a corresponding manner together with the
feed pump 19 and forced-oil line 30. The forced-oil supply with the
bearings of the drive shaft 9 via bores 46 is also indicated in
FIG. 3.
[0045] It is particularly advantageous to arrange a
pressure-maintaining valve 32 in the overflow line 34', which
guides the mixed leakage of diesel oil and smaller amount of
lubricating oil and is connected to the annular collecting and
mixing space 35. This pressure-maintaining valve 32, which is
loaded, for example, by a compression spring, enables a somewhat
increased pressure to be built up upstream of this valve and
therefore also in the annular collecting and mixing space 35. Owing
to this increase in pressure in the space 35, the direction of flow
of the leakage can be affected in such a manner that virtually no
lubricating oil at all can pass into the mixing space 35, this
being an essential requirement in conjunction with the
high-pressure pumps formed in accordance with the invention.
[0046] However, in this case, depending on the amount of increase
in pressure, a very small amount of diesel oil can pass from the
annular collecting space 35 into the oil return-flow annular space
41' and therefore into the lubricating-oil tank 40. However, this
amount of diesel oil is so small that the lubricating oil is
thereby only insignificantly diluted, i.e. is virtually not
diluted. In this case, the mixing of the very small amount of
diesel oil with the lubricating oil is not a problem both with
respect to the oiliness and also in terms of combustion.
[0047] Furthermore, the mixing of the diesel oil and lubricating
oil in the annular collecting and mixing space 35 can be affected
by the length "L" of the extremely small gap between the plunger 14
and plunger bore 37. It is particularly favorable if "L" is greater
than 2.times.E=H, i.e. greater than the stroke of the eccentric 10
and therefore of the plunger 14. During a plunger stroke, particles
are moved in the extremely small gap at most by the distance H.
Together with the increase in pressure in the annular space 35,
mixing can be effectively avoided.
[0048] Two measures of increase in pressure and length "L" may also
be taken independently of each other.
[0049] In one variant (not illustrated) the pressure-maintaining
valve 32 can be controlled (for example electrically or
electronically) in order to be able to adapt the increase in
pressure in the annular space 35 to the operating state of the pump
and/or of the engine, in order to obtain a minimal mixing.
[0050] The sectional illustration according to FIG. 4 shows the
position of the channels running axially parallel according to
FIGS. 2 and 3 and, in particular, shows the bore 24" which cannot
be seen in FIG. 2 and which constitutes the low-pressure supply
line for diesel oil.
[0051] FIG. 5 shows a refinement of a modularly constructed
high-pressure pump according to the invention that is expanded in
comparison to the embodiment according to FIG. 2. In this case,
three modular pump units 2 are combined with two line modules 1, so
that in total twelve cylinder/plunger units are in use. In this
refinement, it can be seen that line modules 2 can be formed both
with exclusively continuous channels and also with channels which
are continuous and branch outward. Both line modules 1 can be used
at the same time for the mounting of the drive shaft 9.
[0052] FIG. 6 shows a high-pressure pump which is reduced in
comparison to the embodiment according to FIG. 2 and in which a
total of just four plungers are used, said plungers being provided
with high-pressure parts 7 in a housing 22 in the manner already
explained.
[0053] The line module 1 used here is used, in turn, for mounting
the shaft, but has, on the one hand, channel sections which lead
outward and, on the other hand, continuous channels 31 for the
forced-oil supply of the pump. The housing 22 remains identical to
that according to FIGS. 1 and 2. Since the line module 1 takes on
at the same time the function of an outer end wall of the housing,
it is, by contrast, slightly modified, since not all of the channel
sections can be permeable.
[0054] FIG. 7 shows a sectional illustration of a pump similar to
FIG. 1, but instead of a rolling ring 11 a two-part sliding shoe
47, 47' is used. The two sliding-shoe parts 47, 47' are held
together by means of screws 48. A sliding bearing or a ball bearing
can be provided between the eccentric section 10 and this two-part
sliding shoe 47, 47'. Since the eccentric space 58 is filled with
lubricant, no annoying friction occurs between the flat sides 64 of
the sliding shoe 47, 47' and the cup tappet 36 or a plunger 14
which is optionally directly actuated.
[0055] A substantial advantage of the sliding-shoe arrangement
resides in the fact that the sliding shoes can be fitted without
any problem even if the rolling rings 11 used according to the
figures explained above between the line modules 1 can no longer be
pushed through the bearings 59 which are provided.
[0056] If appropriate, a combination of rolling rings and sliding
shoes may also be used, but preferably all of the rolling rings are
replaced by sliding shoes 47, 47'.
[0057] The present application claims priority to Swiss Patent
Application 2002 1702/02 filed on Oct. 14, 2002, which is
incorporated herein by reference in its entirety.
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