U.S. patent application number 11/721344 was filed with the patent office on 2009-09-24 for pumping unit.
Invention is credited to Benjin Luo, Ulrich Mueller, Fevzi Yildirim.
Application Number | 20090238680 11/721344 |
Document ID | / |
Family ID | 35520982 |
Filed Date | 2009-09-24 |
United States Patent
Application |
20090238680 |
Kind Code |
A1 |
Yildirim; Fevzi ; et
al. |
September 24, 2009 |
PUMPING UNIT
Abstract
In the pumping unit disclosed, the friction acting on the
impeller is reduced, and the efficiency is increased by at least
two adjacent indentations of at least one face end of the impeller
and/or of the at least one end wall of the pump chamber communicate
with one another via a respective groove.
Inventors: |
Yildirim; Fevzi; (Gerlingen,
DE) ; Mueller; Ulrich; (Gerlingen, DE) ; Luo;
Benjin; (Korntal, DE) |
Correspondence
Address: |
RONALD E. GREIGG;GREIGG & GREIGG P.L.L.C.
1423 POWHATAN STREET, UNIT ONE
ALEXANDRIA
VA
22314
US
|
Family ID: |
35520982 |
Appl. No.: |
11/721344 |
Filed: |
October 17, 2005 |
PCT Filed: |
October 17, 2005 |
PCT NO: |
PCT/EP05/55314 |
371 Date: |
June 11, 2007 |
Current U.S.
Class: |
415/121.2 |
Current CPC
Class: |
F04D 5/002 20130101;
F04D 29/188 20130101 |
Class at
Publication: |
415/121.2 |
International
Class: |
F04D 29/70 20060101
F04D029/70 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 17, 2004 |
DE |
10 2004 060 904.7 |
Claims
1-10. (canceled)
11. A pumping unit having an impeller disposed in a pump chamber
and drivable to rotate by means of an actuator, the impeller
comprising two face ends, an end wall of the pump chamber
diametrically opposite each free end, a plurality of indentations
providing hydrodynamic support in at least one of the face ends of
the impeller and/or at least one of the end walls of the pump
chamber, and a respective groove providing fluid communication
between at least two adjacent indentations of the at least one face
end and/or of the at least one end wall.
12. The pumping unit as defined by claim 11, wherein the
indentations and/or the grooves are disposed annularly.
13. The pumping unit as defined by claim 11, wherein the
indentations and/or the grooves extend in arclike, split-ringlike,
oblong slot-like or similar form.
14. The pumping unit as defined by claim 11, wherein the
indentations and/or the grooves form a common ring.
15. The pumping unit as defined by claim 11, wherein the
indentations have a greater depth than the grooves.
16. The pumping unit as defined by claim 11, wherein the
indentations each have at least one face that is oblique with
respect to the face ends and/or the end walls for hydrodynamic
support of the impeller.
17. The pumping unit as defined by claim 16, wherein the at least
one oblique face, when the indentations are disposed on the
impeller, is each provided on a trailing end of the indentation
relative to a direction of rotation of the impeller.
18. The pumping unit as defined by claim 16, wherein the at least
one oblique face, when the indentations are disposed on the end
walls of the pump chamber, is each provided on a downstream end of
the indentation.
19. The pumping unit as defined by claim 6, wherein the
indentations each have a lowest point that extends parallel to the
at least one face end and/or end wall.
20. The pumping unit as defined by claim 11, wherein the
indentations of one face end of the impeller are diametrically
opposite the indentations of the other face end of the impeller
mirror-symmetrically relative to a middle face, and the
indentations that are diametrically opposite mirror-symmetrically
are joined together via a pressure equalization conduit.
Description
PRIOR ART
[0001] The invention is based on a pumping unit as generically
defined by the preamble to the main claim. A pumping unit is
already known from European Patent Disclosure EP 1 091 127 A1, with
an impeller which is disposed in a pump chamber and is drivable to
rotate by means of an actuator and has two face ends, diametrically
opposite each of which is a respective end wall of the pump
chamber, and a plurality of indentations for hydrodynamic support
in both face ends of the impeller. A disadvantage is that dirt
particles can collect in the indentations. If the dirt particles
are flushed out of the indentations, they cause increased friction
in the region between the annularly disposed indentations and hence
cause scratches, since the axial gap there between the impeller and
the pump chamber is smaller than the region of the
indentations.
ADVANTAGES OF THE INVENTION
[0002] The pumping unit of the invention having the definitive
characteristics of the body of the main claim has the advantage
over the prior art that in a simple way, an improvement is obtained
such that at least two adjacent indentations of the at least one
face end and/or of the at least one end wall communicate with one
another via a respective groove. In this way, the axial gap in the
region between the indentations is increased in size, so that the
dirt particles cannot cause increased friction and scratches
there.
[0003] By the provisions recited in the dependent claims,
advantageous refinements of and improvements to the pumping unit
defined by the main claim are possible.
[0004] In an advantageous version, the indentations and grooves are
disposed annularly and extend in arclike, split-ringlike, oblong
slot-like or similar form. The indentations and the grooves are
advantageously disposed on a common ring.
[0005] It is furthermore advantageous if the indentations have a
greater depth than the grooves, since in this way oblique faces can
be embodied that achieve a hydrodynamic support of the
impeller.
[0006] It is especially advantageous that the indentations each
have at least one face that is oblique with respect to the face
ends and/or the end walls, for hydrodynamic support of the
impeller, since in this way the axial position of the impeller is
adjusted such that the two axial gaps between the impeller and the
end walls of the pump chamber are at least nearly the same size. As
a result, the friction acting on the impeller is reduced, and the
efficiency of the pumping unit is increased. The at least one
oblique face, when the indentations are disposed on the impeller,
is each provided on a trailing end of the indentation relative to a
direction of rotation of the impeller, and when the indentations
are disposed on the end walls of the pump chamber, is each provided
on a downstream end of the indentation.
[0007] It is also advantageous if the indentations each have a
lowest point that extends parallel to the at least one face end
and/or end wall.
[0008] It is moreover advantageous if the indentations of one face
end of the impeller are diametrically opposite the indentations of
the other face end of the impeller mirror-symmetrically relative to
a middle face, and the indentations that are diametrically opposite
mirror-symmetrically are joined together via a pressure
equalization conduit. In this way it is attained that the pressure
in the two indentations joined via the pressure equalization
conduit is equalized.
DRAWINGS
[0009] Exemplary embodiments of the invention are shown in
simplified form in the drawings and described in further detail in
the ensuing description.
[0010] FIG. 1, in section, shows a fragmentary view of the pumping
unit of the invention;
[0011] FIG. 2 shows an impeller of the pumping unit;
[0012] FIG. 3 is a sectional view of the impeller taken along the
line III-III in FIG. 2;
[0013] FIG. 4 is a sectional view of the pumping unit taken along
the line indentation-IV in FIG. 1;
[0014] FIG. 5 is a sectional view of the pumping unit taken along
the line V-V in FIG. 1 in a second exemplary embodiment; and
[0015] FIG. 6 is a sectional view with the impeller and with
indentations, disposed in an end wall of the pump chamber, in
accordance with the second exemplary embodiment.
DESCRIPTION OF THE EXEMPLARY EMBODIMENTS
[0016] FIG. 1 shows a pumping unit of the invention.
[0017] The pumping unit of the invention serves to pump a fluid,
such as fuel, from a supply container to an internal combustion
engine, for instance via a pressure line.
[0018] The pumping unit of the invention is embodied as a flow
pump, such as a peripheral pump or lateral channel pump, and has a
pump housing 1 which has a pump part 2 and a motor part 3.
[0019] The pump part 2 has a pump chamber 4, in which an impeller 5
revolves as it rotates about a rotationally symmetrical pump axis
8. The impeller 5 is driven by an actuator 9, provided in the motor
part 3, via a drive shaft 10. The actuator 8 is an electric motor,
for instance, and is disposed in a motor compartment 7 of the motor
part 3.
[0020] A region upstream of the pump chamber 4 is called the intake
side, and a region downstream of the pump chamber 4 is called the
compression side of the unit.
[0021] The pump chamber 4 has a pump chamber inlet 11 and a pump
chamber outlet 12. The pump chamber 4 is defined by two end walls
diametrically opposite one another in the direction of the pump
axis 8, that is, a first end wall 15 and a second end wall 16, the
pump chamber inlet 11 being provided in the first end wall 15 and
the pump chamber outlet 12 being provided in the second end wall
16, and is defined in the radial direction relative to the pump
axis 8 by an annular wall 17.
[0022] The impeller 5 has a plurality of impeller blades 5.1, and a
blade chamber 5.2 is formed between blades. The blade chambers 5.2
are open toward the end walls 15, 16 and are closed radially
outward for instance relative to the pump axis 8 by a ring 5.3,
which is disposed on the radially outer ends of the impeller blades
5.1. However, the blade chambers 5.2 may expressly also be open
radially outward and not have any ring 5.3.
[0023] Annular feed conduits 14 are disposed in the end walls 15,
16, in the radial region of the impeller blades 5.1.
[0024] The first end wall 15 is part of an intake cap 18, for
instance, and the second end wall 16 and the annular wall 17 are
for instance part of a pressure cap 19. An inlet conduit 22 is
provided in the intake cap 18 and discharges into the pump chamber
4 via the pump chamber inlet 11; the fluid pumped by the pumping
unit leaves the pump chamber 4 via the pump chamber outlet 12. The
pump chamber 4 communicates fluidically with the motor compartment
for instance via the pump chamber outlet 12 and an outlet conduit
23 that is provided in the pressure cap 19.
[0025] The pressure cap 19 has a through opening 24. The drive
shaft 10, mechanically coupled with the actuator 9, begins at the
motor compartment 7 and protrudes through the through opening 24 of
the pressure cap 19 into the pump chamber 4.
[0026] The axial width of the pump chamber 4 is greater than the
axial width of the impeller 5, so that one axial gap 20 each
approximately ten to thirty micrometers wide exists between the
impeller 5 and the respective end walls 15, 16. The difference
between the width of the pump chamber 4 and the width of the
impeller 5 is defined as the total axial gap.
[0027] The impeller 5 is slipped for instance onto the drive shaft
10 protruding into the pump chamber 4; for this purpose, the
impeller 5 has an impeller opening 25, into which the drive shaft
10 at least protrudes so as to be connected to the impeller by
positive and/or nonpositive engagement. The impeller 5 is supported
on the drive shaft 10 for instance in such a way that it is movable
axially between the first end wall 15 and the second end wall
16.
[0028] The impeller 5 has a first face end 28, which is oriented
toward the first end wall 15 of the pump chamber 4, and a second
face end 29, which is oriented toward the second end wall 16 of the
pump chamber 4.
[0029] In at least one of the face ends 28, 29 of the impeller 5
and/or at least one of the end walls 15, 16 of the pump chamber 4,
a plurality of indentations 38 are provided, for hydrodynamic
support of the impeller 5. In FIG. 1, the indentations 38 are
disposed for instance on the face ends 28, 29 of impeller 5.
However, in a second exemplary embodiment, they may instead be
provided on the end walls 15, 16 of the pump chamber 4. The
indentations 38 are embodied in such a way that they act like a
hydrodynamic bearing and in this way adjust the axial position of
the impeller 5 between the first end wall 15 and the second end
wall 16 of the pump chamber in such a way that two equal-sized
axial gaps 20 are created between the impeller 5 and the end walls
15, 16. As a result, only slight forces of friction act on the
impeller 5, so that the efficiency of the pumping unit is
improved.
[0030] The pumping unit aspirates fluid, for instance, from a
supply container 32 via an inlet conduit 22, the pump chamber inlet
11, the pump chamber 4, the pump chamber outlet 12, the outlet
conduit 23, and the motor compartment 7 of the motor part of the
pump housing 1, and pumps the fluid, such as fuel, via a pressure
line 33, to an internal combustion engine 34, for instance. In the
pressure line 33, a check valve 35, for instance, is provided in
order to maintain a predetermined pressure in the pressure line 33
after the pumping unit has been shut off.
[0031] FIG. 2 shows an impeller of the pumping unit with
indentations in a first exemplary embodiment of the pumping unit of
the invention.
[0032] In the impeller of FIG. 2, the elements that remain or
function the same as in the pumping unit of FIG. 1 are identified
by the same reference numerals.
[0033] The indentations 38 are provided for instance radially
inside the impeller blades 5.1 of the impeller 5 and are disposed
located on an imaginary circular ring. The ring is provided
centrally, for instance, relative to the pump axis 8. By way of
example, four indentations 38 are distributed uniformly over the
circumference of the ring. However, it is expressly possible for an
arbitrary number of indentations 38 to be provided. The
indentations 38 extend for instance in arclike, split-ringlike,
oblong slot-like or similar form. The indentations 38 each have one
face 39 that is oblique relative to the face ends 28, 29 for the
sake of hydrodynamically supporting the impeller 5. The oblique
face 39 for hydrodynamic support is disposed on a trailing end of
the indentation 38, with respect to a direction of rotation 31 of
the impeller 5. Each of the indentations 38 has a lowest point 40
that extends for instance parallel to the face ends 28, 29. By way
of example, the lowest point 40 of the indentations 38 is adjacent
to two oblique faces 39, one leading and the other trailing. In the
first exemplary embodiment, the leading oblique face 39 has a
shorter length, for instance a shorter arc length, than the oblique
face 39 that is trailing in the direction of rotation. The oblique
face 38 leading in the direction of rotation may also be omitted
and replaced with a steplike shoulder, since it makes no
contribution to the hydrodynamic support.
[0034] According to the invention, at least two adjacent
indentations 38 of the at least one face end 28, 29 and/or of the
at least one end wall 15, 16 communicate with one another via a
respective groove 42. In the first exemplary embodiment, both face
ends 28, 29 of the impeller 5 are provided with indentations 38.
For example, each indentation 38 communicates with the respective
adjacent indentation 38 via a groove 42. The grooves 42 extend for
instance in arclike, ringlike or similar for, so that the
indentations 38 and the grooves 42 together form one common ring.
The indentations 38 and grooves 42, however, remain different at
least in the respect that the depth of the grooves 42 is less than
the depth of the lowest point 40 and of the oblique faces 39 of the
indentations 38 (FIG. 3). The width Bn of the grooves 42, measured
in the radial direction with respect to the pump axis 8, is for
example equal to the width Bv, measured radially with respect to
the pump axis 8, of the indentations 38, but may also be
different.
[0035] The oblique faces 39 of the indentations 38 are formed by
the provision that the pressure equalization conduits of the
indentations 38, beginning from the lowest point 40 of each, to the
adjacent groove 42 decreases, for instance continuously.
[0036] FIG. 3 shows a sectional view of the impeller taken along
the line III-III in FIG. 2.
[0037] In the region of the lowest point 40, the indentations 38
extend for instance approximately parallel to the face ends 28, 29.
After that, viewed counter to the direction of rotation 41, they
extend along a trailing oblique face 39, with a reduction in the
depth, in the direction of a trailing groove 42 in terms of the
direction of rotation 41 and discharge into this groove. Viewed in
the direction of rotation, the depth of the indentation 38
decreases, either via a steplike shoulder 43 shown in dashed lines
or via a leading oblique face 39 and discharges into a leading
groove 42.
[0038] The indentations 38 of one face end 28 of the impeller 5 are
diametrically opposite the indentations 38 of the other face end 29
of the impeller 5, for instance mirror-symmetrically relative to a
middle face 45, and the indentations 38 diametrically opposite one
another mirror-symmetrically communicate with one another via a
pressure equalization conduit 46. In this way, an equally high
pressure builds in both of the indentations 38 that communicate via
the pressure equalization conduit 46. The pressure equalization
conduit 46 discharges into the indentation 38 for instance in each
case in the region of the lowest point 40.
[0039] The fluid located in the axial gap 20 is entrained in the
direction of rotation 41 upon the rotation of the impeller 5 and
has a relative speed oriented counter to the direction of rotation
41 with respect to the impeller 5. The fluid in the axial gap 20
therefore flows through the indentations 38 and the grooves 42
counter to the direction of rotation 41. In the region of the
trailing oblique face 39, the flow cross section narrows in
wedgelike form between the face ends 28, 29 of the impeller 5 and
the end walls 15, 16 of the pump chamber 4, so that an increasingly
higher pressure in the fluid builds up and acts on the respective
face end 28, 29 of the impeller 5 and in this way adjusts the axial
position of the impeller 5 in such a way that axial gaps 20 of
equal size result.
[0040] FIG. 4 is a sectional view of the pumping unit taken along
the line indentation-IV in FIG. 1 and FIG. 5 is a sectional view of
the pumping unit taken along the line V-V in FIG. 1 in a second
exemplary embodiment.
[0041] In the pumping unit of FIG. 4 and FIG. 5, the elements that
remain the same or function the same as in the pumping unit of
FIGS. 1 through 3 are identified by the same reference
numerals.
[0042] The second exemplary embodiment of FIG. 4 differs from the
first exemplary embodiment of FIGS. 1 through 3 in that the
indentations 38 are disposed not on the two face ends 28, 29 of the
impeller 5 but rather on the two end walls 15, 16 of the pump
chamber 4. The pressure equalization conduits 46 are omitted. The
indentations 38, when disposed on the end walls 15, 16 of the pump
chamber 4 in contrast to the disposition on the impeller 5,
experience a flow through them in the direction of rotation of the
impeller 5. The oblique faces 39 for hydrodynamic support should
therefore each be disposed on one downstream end, in terms of the
flow direction in the axial gap 20, of the indentation 38.
[0043] In the second exemplary embodiment, the indentations 38 are
disposed radially inside the feed conduit 14 with respect to the
pump axis 8. In the region of the lowest point 40, the indentations
38 extend for instance at least approximately parallel to the end
walls 15, 16. Downstream, they extend via a rear oblique face 39,
in terms of the flow direction in the axial gap 20, for
hydrodynamic support with a reduction in depth, as far as a
downstream groove 42 and discharge into it. Upstream, the depth of
the indentation 38 decreases, either via a steplike shoulder 43 or
via an upstream oblique face 39 and discharges into a groove 42
located upstream in terms of the flow direction.
[0044] The indentations 38 of the one end wall 15 of the pump
chamber 4 are diametrically opposite the indentations 38 of the
other end wall 16 of the pump chamber 4, for instance
mirror-symmetrically relative to a middle face that is located in
the middle between the end walls 15, 16 and extends parallel to
them.
[0045] FIG. 6 is a sectional view with the impeller and with
indentations, disposed in an end wall of the pump chamber, in
accordance with the second exemplary embodiment.
[0046] In the pumping unit of FIG. 6, the elements that remain the
same or function the same as in the pumping unit of FIGS. 1 through
5 are identified by the same reference numerals.
* * * * *