U.S. patent application number 12/093433 was filed with the patent office on 2009-05-07 for fluid pump.
This patent application is currently assigned to PIERBURG GMBH. Invention is credited to Albert Genster.
Application Number | 20090116981 12/093433 |
Document ID | / |
Family ID | 37603106 |
Filed Date | 2009-05-07 |
United States Patent
Application |
20090116981 |
Kind Code |
A1 |
Genster; Albert |
May 7, 2009 |
FLUID PUMP
Abstract
The invention relates to an electric fluid pump with a
semi-axial construction, wherein the pump housing (32, 33, 34) has
at least two identical pump housing parts (33, 34). This feature of
the invention reduces the number of different components required
to manufacture the electric fluid pump and thus reduces costs while
achieving a high operating efficiency.
Inventors: |
Genster; Albert; (Neuss,
DE) |
Correspondence
Address: |
GRIFFIN & SZIPL, PC
SUITE PH-1, 2300 NINTH STREET, SOUTH
ARLINGTON
VA
22204
US
|
Assignee: |
PIERBURG GMBH
Neuss
DE
|
Family ID: |
37603106 |
Appl. No.: |
12/093433 |
Filed: |
October 10, 2006 |
PCT Filed: |
October 10, 2006 |
PCT NO: |
PCT/EP2006/009762 |
371 Date: |
May 12, 2008 |
Current U.S.
Class: |
417/410.1 |
Current CPC
Class: |
F04D 13/0606 20130101;
F04D 29/528 20130101; F04D 29/588 20130101; F04D 29/426
20130101 |
Class at
Publication: |
417/410.1 |
International
Class: |
F04B 35/04 20060101
F04B035/04 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 10, 2005 |
DE |
1020050540600 |
Claims
1. A fluid pump for internal combustion engines, comprising: an
electric motor with a rotor arranged in a motor housing and a
stator, wherein the rotor is arranged on a drive shaft at least in
a manner secured against rotation; an impeller fastened on the
drive shaft; at least one set of guide vanes arranged behind the
impeller in a flow direction of fluid to be conveyed; and a pump
housing enclosing the motor housing, the impeller and the guide
vanes, and a pressure port and an intake port are arranged opposite
axial ends of the pump housing, wherein the fluid pump is
configured as a semi-axial pump, and wherein the pump housing
comprises at least two identical pump housing parts, one of which
is a suction-side pump housing part and the other one is a
pressure-side pump housing part, and the identical pump housing
parts each comprise a first cylindrical section serving as an
intake or pressure port, respectively, and that is adjoined by a
flaring section terminating in a second cylindrical section of
larger diameter, and the impeller of the fluid pump is arranged in
the suction-side pump housing part in a transition portion between
the first cylindrical section and the flaring section.
2. The fluid pump for internal combustion engines of claim 1,
wherein the guide vanes are arranged in a cylindrical pump housing
part situated axially between the two identical pump housing parts.
Description
[0001] This is a National Phase Application in the United States of
International Patent Application No. PCT/EP2006/009762 filed Oct.
10, 2006, which claims priority on German Patent Application No. 10
2005 054 060.0, filed Nov. 10, 2005. The entire disclosures of the
above patent applications are hereby incorporated by reference.
FIELD OF THE INVENTION
[0002] The invention is directed to a fluid pump for internal
combustion engines, comprising an electric motor with a rotor
arranged in a motor housing and a stator, the rotor being arranged
on a drive shaft at least in a manner secured against rotation, an
impeller fastened on the drive shaft, at least one set of guide
vanes arranged behind the impeller in the flow direction of the
fluid to be conveyed, and a pump housing enclosing the motor
housing, the impeller and the guide vanes and at which a pressure
port and an intake port are arranged opposite the axial ends.
BACKGROUND OF THE INVENTION
[0003] Fluid pumps for internal combustion engines are used
especially as coolant pumps in the cooling circuit. Whereas, in the
past, a direct coupling with the engine speed existed and the pumps
were driven by belt or chain drives, more recent engines
increasingly use electric variable speed coolant pumps with a can,
so as to realize a modern thermal management. Thus, an excessive
delivery rate can be prevented, so that, for example, the internal
combustion engine can be heated up faster after a cold start. The
delivery rate can be controlled according to the actually required
cooling capacity.
[0004] Such a pump is known, for example, from MTZ No. 11, vol.
2005 (p. 872-877). This electric coolant pump comprises an EC motor
as the drive unit and has a pump head with an axial inlet and a
tangential outlet. The components and especially the housing parts
used therein are rather large for the power input of the pump,
since a relatively large drive motor has to be used.
[0005] Thus, US 2002/0106290 A1 discloses an electric fluid pump of
semi-axial construction, whereby, with the same power input to the
electric motor, the electric motor can be made smaller to obtain
higher speeds, so that the same delivery rate can be obtained with
a more compact structure. It comprises a completely enclosed
electromotor with a guide vanes provided at the outer side thereof.
However, behind the guide vanes, seen in the flow direction,
obstacles are formed that hinder the establishing of the electric
contacting to the electronic unit.
[0006] On the impeller side, the entire motor is sealed with
gaskets from the environment. It is at least debatable whether such
a sealing at the rotating parts is sufficient.
[0007] The pump housing is bipartite and has various steps and
through holes for electric contacting. Depending on the desired
maximum delivery rate, different electric motors and housings must
be designed. Likely, a completely irrotational flow is not achieved
due to the rather short guide vanes. Further, the pressure loss due
to the passages of the electric contacts is rather high so that the
gain in the power input of the electric motor is partly thwarted by
the pressure losses occurring.
[0008] Due to the relative arrangement of the housings, the same
have to be manufactured with high production accuracy, they have to
be reconfigured for higher delivery rates and have to be mounted in
a troublesome manner. No provisions are made to prevent errors upon
mounting.
[0009] In addition, radial and axial pumps are known from EP 0 566
087 A1 and DE 202 01 183 U1, wherein the suction and pressure ports
are made from identical housing parts. However, these cause high
pressure losses and thus a low efficiency.
[0010] Therefore, it is an object of the invention to configure
especially the pump housing such that production flaws can be
compensated, a reduced number of different components is obtained
and assembly errors are minimized, while at the same time a high
efficiency of the pump is to be achieved.
SUMMARY OF THE INVENTION
[0011] This object is achieved with the characterizing part of the
main claim. Thereby, the number of different components and thus
the costs are reduced, while a high efficiency is to be realized.
Moreover, the connection with a suction-side and a pressure-side
pump housing part is simple to make, and little loss occurs. Thus,
intake and pressure ports can be integrated in these parts.
Further, these are the largest and therefore most expensive parts
in the production. Notably, tooling costs are saved. Assembly
errors caused by confusing the mounting direction are excluded. The
shape of the individual ports facilitates the connection to the
axially adjacent housing parts and provides for a steady low-loss
transition when the flow is deflected. Mounting into a cooling
system is readily realized because of the axial position of the
suction port with respect to the pressure port in the cooling
system. The package size, given a certain motor size to be used, is
minimized. Further, no long inflow channel exists and a good
efficiency is achieved due to the semi-axial blading. No additional
space for the impeller is required. Thus, only a small mounting
space is required. High production accuracies are not required.
[0012] In a particular embodiment, the set of guide vanes is
arranged in a cylindrical pump housing part arranged axially
between the two identical pump housing parts. This simplifies the
shape and thus the production of the identical pump housing parts,
since no direct abutment of the inner surfaces at the necessary
guide vanes is required. Thus, the production accuracy can be
reduced.
[0013] Accordingly, a fluid pump is provided which has a small
number of different components, is adapted to be mounted in a
simple manner and with little probability of error, and, due to the
identical construction of the pump housing parts, reduces tooling
and production costs especially with small quantities.
[0014] An embodiment of the invention is illustrated in the drawing
and will be detailed hereinafter.
BRIEF SUMMARY OF THE DRAWING
[0015] The FIGURE is a side elevational sectional view of a fluid
pump according to the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0016] The fluid pump illustrated in the FIGURE, which is
particularly suited as a coolant pump in internal combustion
engines, is driven by an electronically commuted electric motor 1,
formed by a stator 2 and a rotor 4 arranged on a drive shaft 3. The
axial end of the drive shaft 3 is provided with an impeller 5 that
is realized in a semi-axial construction and by whose rotation the
fluid to be conveyed, especially a coolant, is conveyed
substantially axially from an intake port 6 through the fluid pump
to a pressure port 7.
[0017] The electric motor 1 is arranged in a motor housing formed
by a first, suction-side motor housing part 8 and a second,
pressure-side motor housing part 9. The drive shaft 3, on which the
impeller 5 is arranged, is passed through the suction-side motor
housing part 8. For this purpose, the suction-side motor housing
part 8 has a bore 10 with a first bearing 11 being arranged therein
for supporting the drive shaft 3. Behind the first bearing 11, seen
from the suction side, an ceramic axial sliding bearing 12 as well
as a rubber sleeve 13 and a spacer 14 are situated. This assembly
allows to achieve a sufficiently vibration-damped support of the
impeller side of the drive shaft 3 of the electric motor 1. The
spacer serves to widen the distance between the first bearing 11
and a second bearing 15, whereby an angular error caused when
making the bore 10 for receiving the bearings can be compensated
better.
[0018] Further, behind the spacer 14, a rotor pack 16 is arranged
on the shaft, comprising axially extending slits for receiving
magnets 17 corresponding with a stator coil 18 in a manner known
per se. The rotor 4 is delimited axially and radially by an
enclosure 19. The stator coil 18 is wound on an insulating body 20
and axially delimits a stator pack 21 in a manner known per se. To
close the magnetic circuit, this stator pack 21 is positively
connected with a magnetic yoke 22. This magnetic yoke 22 rests
against an abutment 23 formed on an inner surface of the first
suction-side motor housing part 8.
[0019] The rotor 4 is separated from the stator 2 by a can 24
resting on the suction side of the pump in a corresponding
receiving opening 25 of the suction-side motor housing part 8, and
whose opposite axial end is arranged, in turn, in a corresponding
receiving opening 26 of the pressure-side motor housing part 9. The
stator 2 with its sensitive coil 18 is thus situated in a dry space
separated by the two motor housing parts 8 and 9 and the can
24.
[0020] Provided at the pressure-side end of the can 24 is a closure
member 27 in which the second bearing 15 is arranged to support the
drive shaft 3. This closure member 27 is secured axially by the
pressure-side motor housing part 9, which, with the interposition
of a gasket 28, is arranged in a receiving opening 29 of the
suction-side motor housing part 8.
[0021] The stator coil 18 is contacted, via a bore 30, in the
radial direction through the pressure-side motor housing part 9. To
prevent flow losses caused by such additional built-in means, this
bore is made through supporting ribs 31, as known in prior art,
which ribs are required to provide a pump housing with sufficient
strength and for mounting the same. For this purpose, the
supporting ribs 31 are sufficiently wide and are shaped similar to
an airfoil, so that no constriction of the cross section is formed.
Thus, an electric contact element, not illustrated, can be passed
through the bore 30 to an electronic unit (also not illustrated)
for controlling the motor 1.
[0022] In the embodiment illustrated, the supporting ribs 31 are
formed such that they simultaneously serve as the guide vanes, so
that no additional guide vanes is needed immediately behind the
impeller 5. This allows for a simple manufacturing of the
suction-side motor housing 8 as one piece, with the supporting ribs
and a cylindrical radially outer pump housing part 32. This pump
housing part 32 encloses the radially inner motor housing part 8,
as well as the entire electric motor 1.
[0023] On the downstream and the upstream side of the housing part
8, 31, 32, two respective identical pump housing parts 33, 34 are
fastened by a screw connection, with a gasket 50 interposed
therebetween. The suction-side pump-housing part 33, flaring in the
direction of flow, comprises the intake port 6 configured as a
cylindrical section 35, as well as an adjoining flaring section 46.
The semi-axial impeller 5 of the fluid pump is arranged in the
transition 37 between the first section 35 and the second section
36. In the present embodiment, the flaring section 36 is adjoined
by another short cylindrical section 38 of larger diameter to
achieve a smooth transition to the cylindrical pump housing part
32.
[0024] Corresponding sections tapering in the direction of flow and
cylindrical sections are also provided at the pressure-side pump
housing part 34, the same reference numerals being used because of
the identity of the parts.
[0025] Moreover, the identical pump housing parts 33, 34 are formed
with grooves 39 into which radial ends 40 of recirculation vanes 41
engage. These recirculation vanes 41 serve as the conducting device
42 by means of which a completely irrotational flow is obtained
behind the pressure port 7. This conducting device 42 is formed on
a surface 43 of the pressure-side motor housing part 9 and becomes
necessary, because the supporting ribs 31 serving as guide vanes
are made rather short and a completely irrotational flow is usually
not achieved in this part of the fluid pump. Moreover, the
pressure-side motor housing part 9 can be made of plastic material,
whereas the suction-side motor housing part should possible be made
of aluminum and is thus more expensive. Such a configuration of the
guide vanes in this portion would require a rather expensive
production method, whereas the conduction device at the plastic
housing part 9 is simple and economic to manufacture.
[0026] The grooves 39 also define the position of the pressure-side
pump housing part 34 with respect to the pressure-side motor
housing part 9. When the pump is assembled and the screws are
tightened to fasten the pressure-side pump housing part 34 to the
cylindrical pump housing part 32, the pressure-side pump housing
part 34, by the recirculation vanes 40, presses the motor housing
part 9 against the motor housing part 8 or into the receiving
openings 29 of the motor housing part 8. Further, the motor housing
part 9 is thereby pressed against the closure member 27 and the can
24, respectively, so that no additional fastening of the two motor
housing parts 8, 9 is required.
[0027] When the pump is running, the rotation of the impeller 5
formed by a plurality of impeller vanes 44 conveys the fluid to be
conveyed, in particular the coolant, through the space between the
pump housing 32, 33, 34 and the motor housing 8 and 9, the fluid
flows past the supporting ribs 31, where a part of the flow
rotation is already removed due to their function as guide vanes,
and it flows on through the conduction device 42 where the still
existing rotation of the flow is removed completely so that the
energy spent is converted as completely as possible into pressure
energy and thus into an axial flow without incurring high friction
losses.
[0028] Behind the impeller 5, a part of the fluid flows through
bores 45 formed in the suction-side motor housing part 8. Another
part of the fluid also flows behind the impeller 5 to the drive
shaft 3, where it flows through between the first bearing 11 and
the drive shaft 3, so that the sliding bearing present is
sufficiently lubricated. Thus, cooling liquid is in the rotor
space, which is conveyed further between the drive shaft 3 and the
second bearing 16, as well as through non-illustrated bores in the
closure member 27 and into a space 46 behind the same. This space
46 is connected with the space behind the same via another bore 47
extending axially through the pressure-side motor housing part 9.
Thus, both a lubrication of the bearings 11, 15 and a possibility
for cooling and discharging possibly existing volumes of air in the
rotor space are obtained.
[0029] This semi-axial pump is especially characterized in that it
can be of a particularly compact structure, since with the same
power input the same delivery rate can be obtained though with a
smaller motor size and an increased speed when compared with known
pumps. This is achieved especially by the extremely reduced
pressure losses in such a design, but also by the semi-axial
construction.
[0030] Moreover, such a pump can be produced very economically,
since fewer differently designed components exist. At the same
time, this reduces the occurrence of possible errors during
assembly. By omitting the additional set of guide vanes and by
integrating the electric contacting in the supporting ribs,
additional components are avoided and pressure losses are reduced.
Thus, on the whole, a higher efficiency is achieved.
[0031] Because of the simplicity of the pump housing parts 33, 34,
it is of course also possible to provide the same with a flange
situated at the pressure port or the intake port, respectively.
This allows both a direct connection to a motor housing and to
connect a plurality of pumps in series to increase the fluid volume
flow conveyed. This becomes possible especially by the fact that
the conduction device 42 creates an irrotational flow so that the
impeller 5 of a downstream pump could be flown to directly without
incurring energy losses. Therefore, when twice the delivery rate of
a pump is required, it is not necessary to build a larger pump with
a corresponding larger motor, but, due to the identity of the
components, one may simply connect the corresponding required
number of pumps in series.
[0032] It is also conceivable, due to the simplicity of the
suction-side pump housing part 33, in particular, to form the same
integrally with valve housing parts so that the pump housing parts
33 could comprise a receptacle for a bypass or an integrated heat
valve. Parts of the housing of an annular slide valve could also be
made integrally with the suction-side pump housing part 33.
[0033] It should be noted that the embodiment illustrated merely is
a possible embodiment of the invention, whose structure may be
altered in several respects without leaving the scope of protection
of the claims.
* * * * *