U.S. patent application number 09/739544 was filed with the patent office on 2001-06-21 for pump for conveying fuel in an internal combustion engine.
This patent application is currently assigned to Hydraulik-Ring GmbH. Invention is credited to Naumann, Ralf, Palesch, Edwin, Sluka, Gerold.
Application Number | 20010004441 09/739544 |
Document ID | / |
Family ID | 7933481 |
Filed Date | 2001-06-21 |
United States Patent
Application |
20010004441 |
Kind Code |
A1 |
Palesch, Edwin ; et
al. |
June 21, 2001 |
Pump for conveying fuel in an internal combustion engine
Abstract
A pump for conveying a liquid has a housing and a shaft
rotatably supported in the housing. An eccentric drive is arranged
in the housing. At least one drive element is provided and is
configured to be driven by the eccentric drive. The shaft is
configured to adjust the eccentricity of the eccentric drive. The
drive element is configured to be adjusted according to the
eccentricity of the eccentric drive by a translatory movement in a
direction transverse to the shaft.
Inventors: |
Palesch, Edwin; (Lenningen,
DE) ; Sluka, Gerold; (Neckartailfingen, DE) ;
Naumann, Ralf; (Crimmitschau, DE) |
Correspondence
Address: |
GUDRUN E. HUCKETT
PATENT AGENT
P.O. BOX 3187
ALBUQUERQUE
NM
87190-3187
US
|
Assignee: |
Hydraulik-Ring GmbH
Limbach-Oberfrohna
DE
|
Family ID: |
7933481 |
Appl. No.: |
09/739544 |
Filed: |
December 18, 2000 |
Current U.S.
Class: |
417/221 |
Current CPC
Class: |
Y10T 74/2112 20150115;
F04B 9/045 20130101; F04B 1/07 20130101; Y10T 74/18056 20150115;
F04B 1/0413 20130101; F04B 49/125 20130101 |
Class at
Publication: |
417/221 |
International
Class: |
F04B 001/06 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 20, 1999 |
DE |
199 61 558.6 |
Claims
What is claimed is:
1. A pump for conveying a liquid, said pump comprising: a housing
(1); a shaft (2) rotatably supported in said housing (1); an
eccentric drive (8, 11) arranged in said housing (1); at least one
drive element (13) configured to be driven by said eccentric drive
(8, 1 1); said shaft (2) configured to adjust an eccentricity of
said eccentric drive (8, 11); wherein said drive element (13) is
configured to be adjusted according to the eccentricity of said
eccentric drive (8, 11) by a translatory movement in a direction
transverse to said shaft (2).
2. The pump according to claim 1, wherein said eccentric drive (8,
11) comprises an inner eccentric (8) and an external eccentric (11)
supported on said inner eccentric (8).
3. The pump according to claim 2, wherein said inner eccentric (8)
is a monolithic part of said shaft (32).
4. The pump according to claim 2, wherein said drive element (13)
is supported on said external eccentric (11).
5. The pump according to claim 4, wherein said drive element (13)
surrounds said external eccentric (11).
6. The pump according to claim 5, wherein said external eccentric
(11) surrounds said inner eccentric (8).
7. The pump according to claim 1, wherein said drive element (13)
has at least one contact surface (15-17) configured to contact at
least one piston (14).
8. The pump according to claim 1, wherein said drive element (13)
is supported on said housing (1) to prevent rotation of said drive
element (13) with said shaft (2).
9. The pump according to claim 8, wherein said drive element (13)
has a first coupling member (21) and is connected to said housing
(1) with said first coupling member (21).
10. The pump according to claim 9, wherein said first coupling
member (21) is penetrated by said shaft (2).
11. The pump according to claim 9, wherein said first coupling
member (21) is configured to be moveable by a translatory movement
in a direction transverse in a plane positioned transversely to
said shaft (2).
12. The pump according to claim 9, wherein said housing (1) has at
least one guide (25, 26) and wherein said first coupling member
(21) has at least one counter guide part (23, 24), wherein said at
least one counter guide part (23, 24) is guided in said at least
one guide (25, 26) of said housing (1).
13. The pump according to claim 12, wherein said first coupling
member (21) is radially guided relative to said shaft (2).
14. The pump according to claim 12, wherein said housing (1) has
two of said guides (25, 26) positioned diametrically opposite one
another, wherein said first coupling member (21) has two of said
counter guide parts (23, 24), wherein each one of said guides (25,
26) receives one of said counter guide parts (23, 24).
15. The pump according to claim 12, wherein said first coupling
member (21) comprises at least one guide (32, 33) and wherein said
drive element (13) comprises at least one counter guide element
(34, 35), wherein said at least one counter guide part (34, 35) is
guided in said at least one guide (32, 33) of said first coupling
member (21).
16. The pump according to claim 15, wherein said drive element (13)
is radially guided relative to said shaft (2).
17. The pump according to claim 15, wherein said first coupling
member (21) has two of said guides (32, 33) positioned
diametrically opposite one another, wherein said drive element (13)
has two of said counter guide parts (34, 35), and wherein each one
of said guides (32, 33) receives one of said counter guide parts
(34, 35).
18. The pump according to claim 15, wherein said at least one guide
(32, 33) of said first coupling member (21) extends perpendicularly
to said at least one guide (32, 33) of said housing (1).
19. The pump according to claim 9, further comprising an adjusting
device (7) coupled to said eccentric drive (8, 11) .
20. The pump according to claim 19, wherein said adjusting device
(7) comprises at least one adjusting element (4) fixedly connected
to said shaft (2).
21. The pump according to claim 20, wherein said adjusting element
(4) is configured to be hydraulically adjusted.
22. The pump according to claim 20, wherein said adjusting device
(7) comprises a rotor (4) and a stator (6), wherein said at least
one adjusting element is said rotor (4).
23. The pump according to claim 19, wherein said eccentric drive
(8, 11) has a second coupling member (36) and is coupled with said
second coupling member (36) to said adjusting device (7).
24. The pump according to claim 23, wherein said second coupling
member (36) is configured to be radially adjusted relative to said
shaft (2).
25. The pump according to claim 24, wherein said second coupling
member (36) has at least two guides (37, 38; 41, 42) angularly
spaced from one another, wherein said external eccentric (11) and
said stator (6) have counter guide parts (39, 40; 43, 44), and
wherein said counter guide parts (39, 40; 43, 44) are guided in
said at least two guides (37, 38; 41, 42) of said second coupling
member (21).
26. The pump according to claim 25, wherein said at least two
guides (37, 38; 41, 42) of said second coupling member (26) are
positioned at a right angle to one another.
27. The pump according to claim 25, wherein said at least two
guides (37, 38; 41, 42) of said second coupling member (36) are
arranged in pairs and positioned diametrically opposite one
another.
28. The pump according to claim 23, wherein said second coupling
member (36) is penetrated by said shaft (2).
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The invention relates to a pump, in particular, for pumping
fuel in an internal combustion engine of a motor vehicle, the pump
comprising a housing in which a shaft is rotatably supported.
[0003] 2. Description of the Related Art
[0004] Conveying pumps are known which continuously convey fuel, in
particular, diesel fuel, from a tank into a reservoir. The
cylinders of the internal combustion engine are connected to the
reservoir by solenoid valves. The greater portion of the fuel is
returned from the reservoir into the tank by means of pressure
limiting valves because only a small portion of the continuously
conveyed fuel is required for the internal combustion process in
the cylinders. The continuous return of the fuel results in
unsatisfactory efficiency. As a result of the continuous conveying
and return action, a great heat development is also observed.
Accordingly, it is not possible to employ a plastic material for
such a pump; it is necessary to employ metal which is more
expensive.
[0005] For conveying the fuel it is also known to provide a vacuum
throttle. Check valves ensure that a sufficient amount of fuel is
always available for the combustion process. The check valves or
their springs have however tolerances so that different amounts of
fuel will enter the cylinders. As a result of the variable degree
of filling, high pulsations occur which result in a strong noise
development. Also, the mechanical loading of the motor cylinders
and their pistons is very high. In order to maintain a relatively
small amount of fuel in circulation, proportional solenoid valves
are adjusted to a middle position so that only a portion of the
fuel is conveyed. As a result of tolerances of the springs of the
proportional solenoid valves, different amounts of fuel are present
in the piston chamber. During the vacuum process vapor bubbles are
formed in the piston chamber which are quickly compressed upon
return of the piston. However, since fuel cannot be compressed, the
piston is thus greatly slowed down so that this results in high
mechanical loading. By means of the proportional solenoid valves,
it is possible to supply per time unit the same amount of fuel,
respectively. However, since the amount of fuel for the internal
combustion process depends on the engine speed (rpm) of the motor,
the proportional solenoid valves must be controlled in a
complicated fashion as a function of the rpm of the motor.
SUMMARY OF THE INVENTION
[0006] It is an object of the present invention to configure the
pump of the aforementioned kind such that it has a good efficiency
and conveys reliably the amount of fuel required for the internal
combustion process.
[0007] In accordance with the present invention, this is achieved
in that the eccentricity of an eccentric drive can be adjusted by
means of the shaft, wherein the eccentric drive is provided for
driving at least one drive element which is adjustable according to
the adjusted eccentricity by a translatory movement in a plane
positioned transverse to the shaft.
[0008] In the pump according to the invention, the drive element is
driven by means of the eccentric drive. Depending on the
eccentricity of the eccentric drive, the drive element is moved or
adjusted by a translatory movement to varying degrees in a plane
positioned transversely to the shaft. With this measure, it is, for
example, possible to adjust in a continuous manner the stroke of a
piston from zero to a maximum value by means of the drive element,
for example, in order to convey a corresponding amount of fuel into
the internal combustion chamber of the motor cylinder. Since the
eccentric drive is coupled with the shaft, the eccentricity can be
adjusted in a simple way as a function of the rpm of the internal
combustion engine. The eccentric drive makes possible a compact
configuration of the pump. It is suitable especially for common
rail systems.
BRIEF DESCRIPTION OF THE DRAWING
[0009] In the drawing:
[0010] FIG. 1 shows in a side view and in a simplified illustration
the pump according to the present invention;
[0011] FIG. 2a shows in a simplified and schematic illustration a
first position of a drive element of the pump according to the
invention for actuating pistons;
[0012] FIG. 2b shows in a simplified and schematic illustration a
second position of the drive element of the pump according to the
invention for actuating pistons;
[0013] FIG. 2c shows in a simplified and schematic illustration a
third position of the drive element of the pump according to the
invention for actuating pistons;
[0014] FIG. 2d shows in a simplified and schematic illustration a
fourth position of the drive element of the pump according to the
invention for actuating pistons;
[0015] FIG. 3a shows in a simplified and schematic illustration a
first position of a coupling member of the pump according to the
invention;
[0016] FIG. 3b shows in a simplified and schematic illustration a
second position of the coupling member of the pump according to the
invention;
[0017] FIG. 3c shows in a simplified and schematic illustration a
third position of the coupling member of the pump according to the
invention;
[0018] FIG. 4 is a plan view onto the pump according to the
invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0019] The pump according to the invention is preferably employed
in common rail systems as they are used in motor vehicles for
conveying fuel, in particular, diesel fuel. By changing the stroke
of the piston, the amount of fuel to be injected can be varied.
[0020] The pump can also be used in other areas, for example, in
the field of high-pressure technology, water jet cutting
technology, high pressure hydroforming, clamping technology,
machine tools and the like.
[0021] The pump has a housing 1 (FIG. 1) which is penetrated by a
rotatably driven shaft 2. In the vicinity of the bottom 3 of the
housing 1, a rotor 4 is fixedly mounted on the shaft 2. It
comprises at least two blades 5 which are positioned diametrically
opposite one another and extend radially. The rotor 4 is surrounded
by a stator 6 which is supported on the shaft 2 so as to be
rotatable relative to the rotor 4. The stator 6 is penetrated by
the shaft 2 and has two chambers which are separated from one
another by a transverse stay into which a rotor blade 5 extends,
respectively. The rotor 4 with the stator 6 form an adjusting
device of the "Schwenkflugel" type (variable geometry or variable
swap type) which is known and is therefore not explained in detail
in this connection. The stator interior is divided by the
transverse stay into two chambers into which the rotor blades 5
project. Each rotor blade 5 divides the stator chamber into two
portions. Hydraulic medium is supplied via the shaft 2 in a manner
known in the art to each chamber portion, receptively, of the two
chambers. In this way, a relative rotation between the rotor 4 as
the adjusting element and the stator 6 can be performed.
[0022] In the area adjacent to the adjusting device 7, the shaft 2
is provided with an inner eccentric 8 which is advantageously
formed as a unitary (monolithic) part of the shaft 2. The inner
eccentric 8 is arranged relative to the shaft 2 such that the
eccentric 8 and the shaft 2 have a common tangent at one location 9
(FIG. 3a).
[0023] An external eccentric 11 is seated on the inner eccentric 8
with interposition of a bearing 10 (FIG. 1). The external eccentric
11 advantageously has the same axial length as the inner eccentric
8. The external eccentric 11 is surrounded with interposition of a
bearing 12 by a drive element 13 (FIGS. 1 and 2). In FIG. 2, the
drive element 13 (slotted link or connecting link) is illustrated
as a circular ring in order to simplify the drawing. As is
illustrated in FIG. 4, the drive element 13 has substantially a
triangular contour. According to the number of the pistons 14 to be
actuated, the drive element 13 is provided at its circumference
with planar surfaces 15 to 17 (FIG. 4) against which the pistons 14
rest. In the illustrated embodiment, the drive element 13 is
provided with three such surfaces 15 to 17, with a piston 14
resting against each surface 15-17, respectively. In FIG. 4, only
one piston 14 is illustrated in order to simplify the drawing. The
planar surfaces 15 to 17 are connected to one another by curved
surfaces 18 to 20 which are positioned on a common circular arc or
cylinder mantle.
[0024] The drive element 13 is guided by means of at least one
coupling member 21 in the housing 1. As illustrated in an exemplary
fashion in FIG. 4, the coupling member 21 has an annular part 22
which is seated external to the inner eccentric 8 on the shaft 2
and from which two arms 23, 24 project radially diametrically. The
arms 23-24 are counter guide parts that engage the guides 25 and 26
provided on the housing. As illustrated in FIG. 4, the arms 23, 24
of the coupling member 21 have parallel extending longitudinal
sides 27, 28; 29, 30 which extend in the radial direction and with
which they are guided in the radial direction on counter surfaces
of the guides 25, 26 on the housing 1. The guides 25, 26 are
arranged such and the arms 23, 24 have such a length that the arms
23, 24 are securely guided on the guides 25, 26 in any displacement
position of the coupling member 21. In order for the coupling
member 21 to be moved in the longitudinal direction of the arms 23,
24 relative to the shaft 2, the annular part 22 of the coupling
member 21 is provided with a corresponding slotted hole 31. Its
width matches the diameter of the shaft 2.
[0025] As illustrated in FIG. 2a, the arms 23, 24 can also be of a
fork-shaped design so that they surround the guides 25, 26 provided
on the housing 1.
[0026] The coupling member 21 is provided with guides 32, 33 (FIG.
2) which also extend diametrically relative to one another and have
an angular spacing of 90.degree. to the guides 25, 26. The guides
32, 33 are provided for guiding the counter guide parts 34, 35
which are provided on the drive element 13. The guides 25, 26 and
32, 33 can be positioned in a common radial plane of the shaft 2
but also in radial planes of the shaft 2 that are axially spaced
from one another. As a result of guiding of the drive element 13 in
the coupling member 21, which, in turn, is guided in the housing 1,
it is ensured that the drive element 13 does not perform a
rotational movement upon rotation of the shaft 2 but is moved by a
translatory movement transverse to the shaft 2. This will be
explained in more detail with the aid of FIGS. 2a to 2c.
[0027] The coupling member 21 is positioned on one side of the two
eccentrics 8, 11. On the oppositely located side of the eccentrics
8, 11 a further coupling member 36 is provided with which the
external eccentric 11 is coupled with the stator 6. The coupling
member 36 is seated on the shaft 2 and has diametrically oppositely
positioned guides 37, 38 with which counter guide parts 39, 40 of
the external eccentric 11 can be radially guided. The coupling
member 36 is furthermore provided with two diametrically oppositely
positioned guides 41, 42 which have an angular spacing of
90.degree., respectively, relative to the guides 37, 38 and by
which counter guide parts 43, 44 of the stator 6 are radially
guided. The coupling member 36 can be moved in the same way as the
coupling member 21 in a radial plane relative to the shaft 2. In
order to make this displacement movement possible, the coupling
member 36 is provided with a slotted hole (not illustrated) whose
width corresponds to the diameter of the shaft 2.
[0028] By relative movement of the two eccentrics 8 and 11 by means
of the adjusting device 7, the eccentricity of the drive element 13
can be adjusted continuously. The greater the eccentricity, the
greater the stroke of the pistons 14. When moved, the drive element
13 transmits the adjusted eccentricity onto the piston 14. Each
piston 14 is loaded by a pressure spring (not illustrated) in the
direction of contacting (resting against) the drive element 13. The
spring force is only of such magnitude that the piston 14 rests
properly and safely at the planar sides 15 to 17 of the piston
14.
[0029] In order to adjust the two eccentrics 8 and 11 relative to
one another, the hydraulic medium is introduced such into the
adjusting device 7 that the relative rotational position between
the rotor 4 and the stator 6 is changed in the required amount. In
FIGS. 3a to 3c, one of the rotor blades 5 which engages the chamber
45 of the stator 6 is schematically illustrated. In the position
according to FIG. 3a, the rotor blade 5 rests against an end wall
46 of the stator chamber 45. In this case, the external eccentric
11 is rotated relative to the inner eccentric 8 such that the
coupling member 36 has a central position relative to the axis 47
of the shaft 2. When the shaft 2 is driven in rotation, the
coupling member 36 is thus not reciprocated.
[0030] In the position according to FIG. 3b, the stator 6 is
rotated relative to the rotor 4 so that the rotor blade 5 now is in
the central position within the stator chamber 45. With this
relative rotation between the rotor 4 and the stator 6, the
external eccentric 11 is rotated by means of the coupling member 36
relative to the inner eccentric 8 and, in this way, a certain
eccentricity of the eccentric drive is adjusted. As a result of the
relative rotation of the rotor 4 relative to the stator 6, the
coupling member 36 is entrained by a corresponding amount by means
of the counter guide parts 43, 44 of the rotor 4 and the guides 41,
42 of the coupling member 36. When comparing FIGS. 3a and 3b, it
becomes clear that the coupling member 36 is moved in the X
direction by this rotation. When the shaft 2 in this intermediate
position is rotated about its axis 47, the coupling member 36
carries out a reciprocating movement in the X-Y plane as a function
of the eccentric movement of the two eccentrics 8, 11. Since the
drive element 13 is seated on the eccentric 11, the drive element
13 is also reciprocated according to the eccentricity in the X-Y
plane. As a result, the pistons 14 are actuated via the planar
surfaces 15 to 17. Accordingly, they carry out a certain stroke
based on the adjusted eccentricity. Since in the illustrated
embodiment the rotor 4 has been rotated relative to the stator 6 by
90.degree. and the stator chamber 45 extends about an angular range
of 180.degree., half the stroke of the piston 14 is generated in
the position according to FIG. 3b.
[0031] As is illustrated in an exemplary manner in FIG. 3c, it is
also possible to rotate, the stator 6 and the rotor 4 relative to
one another such that the rotor blade 5 will come to rests against
the oppositely positioned end wall 48 of the stator chamber 45. By
means of the coupling member 36 the external eccentric 11 is
adjusted relative to the inner eccentric 8 such that the eccentric
drive has its greatest eccentricity. The coupling member 36 has
been moved the farthest in the X direction. Moreover, the coupling
member 36 has been rotated by the positive-locking connection 41,
42; 43, 44 together with the stator 6. When the shaft 2 in the
position according to FIG. 3c is rotated about its axis 47, the
drive element 13 is moved in the X-Y plane as a result of the large
eccentricity by a correspondingly large amount so that the pistons
14 resting against the planar surfaces 15 to 17 of the drive
element 13 carry out their maximum stroke.
[0032] In the manner disclosed, the eccentricity of the eccentric
drive 8, 11 can be continuously adjusted by means of the adjusting
device 7 so that the stroke of the pistons 14 can be controlled
correspondingly finely and can be adjusted to the desired
requirements.
[0033] Since the drive element 13 in operation is moved back and
forth in the X-Y plane, a moment of friction occurs between the
planar surfaces 15 to 17 of the drive element 13 and the
corresponding contact surfaces of the piston 14 which moment of
friction is exerted by the eccentrics 8, 11 onto the drive element
13. The pistons 14 are moved by their stroke movement only in the
stroke direction while the surfaces 15 to 17 of the drive element
13 carry out displacement movements relative to the pistons 14 when
the drive element 13 moves in a translatory fashion back and forth
in the X-Y plane.
[0034] In order to compensate this moment of friction, the drive
element 13 is supported by the coupling member 21 by means of the
arms 23, 24 on the guides 25, 26 connected to the housing. The
FIGS. 2a to 2d show different positions of the drive element 13 and
of the coupling member 21 when the shaft 2 is rotated about its
axis 47. The drive element 13 and the coupling member 21 connected
thereto are moved in the X-Y plane as a function of the adjusted
eccentricity of the eccentric drive 8, 11 . The guides 25, 26
connected to the housing prevent that the coupling member 21 is
rotated about its axis. The coupling member 21 is only
translatorily moved in the X-Y plane, as can be seen when comparing
FIGS. 2a to 2d. The guiding action is realized via the arms 23, 24
and the guides 25, 26 fastened to the housing as well as via the
guides 32, 33 of the coupling member 21 and the corresponding
counter guide parts 34, 35 of the drive element 13. The
housing-connected guides 25, 26 compensate the moments of friction
which are exerted by the pistons 14 onto the drive element 13 by
their translatory movement.
[0035] Based on the position according to FIG. 2a, the shaft 2 is
rotated in clockwise direction. In accordance with the adjusted
eccentricity, the drive element 13, which is arranged on the
external eccentric 11, is moved translatorily in the X-Y plane to
the left, wherein the drive element 13 is guided with its counter
guide parts 34, 35 by the guides 32, 33 of the coupling member 21.
The coupling member 21, in turn, is guided by its arms 23, 24 in
the guides 25, 26 of the housing 1.
[0036] In the position according to FIG. 2c the shaft 2 has been
rotated by a further 90.degree.. In comparison to the position
according to FIG. 2b, the connecting member 21 has been moved in
the downward direction.
[0037] FIG. 2d shows a position which results when the shaft 2 is
rotated further by 90.degree. in the clockwise direction. Now the
drive element 13 has been moved farthest to the right. The coupling
member 21, in comparison to the position according to FIG. 2c, has
been moved upwardly again.
[0038] The course of movement described with the aid of FIGS. 2a to
2d shows that the coupling member 21 and the drive element 13 are
not rotated but are moved translatorily in the X-Y plane.
[0039] By means of the eccentric drive 8, 11, the stroke of the
piston 14 can be continuously adjusted between zero and a maximum
value. The adjusting device 7 serves as the actuation element with
which the position of the two eccentrics 8, 11 relative to one
another can be adjusted. For this purpose, in the manner described
above, a relative rotation between the stator 6 and the rotor 4 is
carried out. Since the rotor 4 is connected fixedly with the shaft
2 and the external eccentric 11 is coupled by means of the coupling
member 36 with the stator 6, the rotation of the shaft 2 causes the
inner eccentric 8 to be rotated relative to the outer eccentric 11.
In this way, it is possible to adjust finally and continuously the
eccentricity of the eccentric drive 8, 11. According to this
eccentricity, the drive element 13 positioned on the external
eccentric 11 is translatorily moved in a radial plane (X-Y plane)
of the shaft 2 when the shaft 2 is driven in rotation. According to
the eccentricity, the stroke of the pistons 14 resting on the drive
element 13 is adjusted. The pump has a very compact configuration
and is comprised of simple components so that the pump operates
flawlessly over a long period of use.
[0040] While specific embodiments of the invention have been shown
and described in detail to illustrate the inventive principles, it
will be understood that the invention may be embodied otherwise
without departing from such principles.
* * * * *