U.S. patent application number 12/093405 was filed with the patent office on 2009-06-18 for fluid pump.
This patent application is currently assigned to PIERBURG GmbH. Invention is credited to Albert Genster.
Application Number | 20090155100 12/093405 |
Document ID | / |
Family ID | 37663301 |
Filed Date | 2009-06-18 |
United States Patent
Application |
20090155100 |
Kind Code |
A1 |
Genster; Albert |
June 18, 2009 |
FLUID PUMP
Abstract
The invention relates to an electric fluid pump with a
semi-axial construction, in which a motor housing part (9),
situated at the pressure end, has a conduction device (42). The
conduction device (42) allows an almost completely irrotational
flow to be achieved so that the kinetic energy of the tangential
component of the flow velocity is converted into pressure energy
with negligible friction losses. This feature of the invention
increases the efficiency of the fluid pump. The dimensions of the
electric motor can therefore be reduced while maintaining the same
delivery quantity.
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: |
37663301 |
Appl. No.: |
12/093405 |
Filed: |
October 10, 2006 |
PCT Filed: |
October 10, 2006 |
PCT NO: |
PCT/EP2006/009763 |
371 Date: |
May 12, 2008 |
Current U.S.
Class: |
417/410.1 |
Current CPC
Class: |
F04D 13/0626 20130101;
F04D 29/548 20130101; F04D 1/04 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 |
10 2005 054.027.9 |
Claims
1. A fluid pump for internal combustion engines, comprising. an
electric motor having 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, wherein a pressure port and an intake port are arranged at
opposite axial ends of the pump housing; wherein a pressure-side
motor housing part of the motor housing includes a conduction
device.
2. The fluid pump for internal combustion engines of claim 1,
wherein the conduction device is formed by recirculation vanes
manufactured integrally with the pressure-side motor housing part
and formed on the surface thereof.
3. The fluid pump for internal combustion engines of claim 1,
wherein the pressure-side motor housing part is tapered in the flow
direction and is enclosed by a correspondingly formed pressure-side
pump housing part.
4. The fluid pump for internal combustion engines of claim 1,
wherein the pressure-side pump-housing part is formed with grooves
into which radial ends of the recirculation vanes extend.
5. The fluid pump for internal combustion engines of claim 4,
wherein the pressure-side motor housing part is adapted to slide
into a receiving opening of an axially adjoining motor housing part
by slipping the pressure-side pump housing part onto the
pressure-side motor housing part, with interposition of a gasket,
wherein the pressure-side motor housing part is fixed by fastening
the pressure-side pump housing part at a pump housing part situated
radially outward with respect to the axially adjoining motor
housing part.
6. The fluid pump for internal combustion engines of claim 1,
wherein the pressure-side pump-housing part has a flange by which
the fluid pump fastens to an internal combustion engine.
7. The fluid pump for internal combustion engines of claim 1,
wherein a plurality of fluid pumps are connected in series via a
flange connection, wherein the flanges are formed at the
pressure-side pump housing part of the first pump and a
suction-side pump housing part of a downstream pump.
8. The fluid pump for internal combustion engines of claim 2,
wherein the pressure-side motor housing part is tapered in the flow
direction and is enclosed by a correspondingly formed pressure-side
pump housing part.
9. The fluid pump for internal combustion engines of claim 2,
wherein the pressure-side pump-housing part is formed with grooves
into which radial ends of the recirculation vanes extend.
10. The fluid pump for internal combustion engines of claim 3,
wherein the pressure-side pump-housing part is formed with grooves
into which radial ends of the recirculation vanes extend.
11. The fluid pump for internal combustion engines of claim 9,
wherein the pressure-side motor housing part is adapted to slide
into a receiving opening of an axially adjoining motor housing part
by slipping the pressure-side pump housing part onto the
pressure-side motor housing part, with interposition of a gasket,
wherein the pressure-side motor housing part is fixed by fastening
the pressure-side pump housing part at a pump housing part situated
radially outward with respect to the axially adjoining motor
housing part.
12. The fluid pump for internal combustion engines of claim 10,
wherein the pressure-side motor housing part is adapted to slide
into a receiving opening of an axially adjoining motor housing part
by slipping the pressure-side pump housing part onto the
pressure-side motor housing part, with interposition of a gasket,
wherein the pressure-side motor housing part is fixed by fastening
the pressure-side pump housing part at a pump housing part situated
radially outward with respect to the axially adjoining motor
housing part.
Description
[0001] This is a National Phase Application in the United States of
International Patent Application No. PCT/EP2006/009763 filed Oct.
10, 2006, which claims priority on German Patent Application No. 10
2005 054.027.9, filed Nov. 11, 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. 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.
[0006] 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.
[0007] 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] DE 202 01 183 U1 discloses an axial pump with an electric
motor enclosed by a housing part having straight supporting ribs
intended to serve as a guide vanes. Due to their straight design,
the pressure loss is very high. In addition, it is most probable
that an irrotational flow is not achieved with this structure.
[0009] It is therefore an object of the invention to achieve an
irrotational outflow with pressure losses as small as possible and
to thereby increase the efficiency while reducing the package size.
Further, various maximum delivery rates are to be achieved, while
using the same housing parts.
SUMMARY OF THE INVENTION
[0010] This object is achieved by providing a pressure-side motor
housing part with a conduction device. This conduction device
allows to obtain an almost completely irrotational flow so that the
kinetic energy of the tangential component of the flow velocity is
converted into pressure energy with low friction losses. This
increases the efficiency of the fluid pump. Thus, in order to
obtain an unaltered delivery rate, it is also possible to reduce
the overall size of the electric motor.
[0011] In a further developed embodiment, the conduction device is
formed by recirculation vanes manufactured integrally with the
pressure-side motor housing part and formed on the surface thereof,
so that no additional components are required and an irrotational
flow with little loss of energy is guaranteed. The recirculation
vanes serve to convert the tangential flow component into an axial
flow component without any significant pressure losses. The
efficiency is increased and the number of components is
reduced.
[0012] Preferably, the pressure-side motor housing part is tapered
in the flow direction and surrounded by a correspondingly shaped
pressure-side pump housing part. Thus, the radial ends of the
recirculation vanes are delimited by the pump housing, so that it
is reliably prevented that the vanes are flown over.
[0013] It is advantageous to form grooves in the pressure-side pump
housing part, the radial ends of the recirculation vanes extending
into these grooves. This again reduces the flow resistance by
preventing an overflowing of the vanes and defines the position of
the motor housing part with respect to the pump housing part, so
that, in turn, assembly errors are avoided, since the grooves serve
as guiding grooves upon assembly.
[0014] In a further developed embodiment, the pressure-side motor
housing part is adapted to be slid into a receiving opening of an
axially adjoining motor housing part by slipping the pressure-side
pump housing part onto the pressure-side motor housing part, with
interposition of a gasket, wherein the pressure-side motor housing
part is fixed by fastening the pressure-side pump housing part at a
pump housing part situated radially outward with respect to the
axially adjoining motor housing part. Accordingly, no fastening
elements have to be used to fasten the pressure-side motor housing
part. The fastening of the pump housing part alone guarantees for a
tight fastening of the motor housing, so that the assembly effort
is reduced.
[0015] Preferably, the pressure-side pump housing part has a flange
via which the fluid pump can be fastened to an internal combustion
engine. Due to the simplicity of the pump housing parts, the
pressure port can be made integrally with the flange, so that the
fluid pump can be flange-mounted directly on a motor housing, for
example, without additional intermediate lines.
[0016] It is particularly advantageous if a plurality of fluid
pumps are connected in series via a flange connection, the flanges
being formed at the pressure-side pump housing part of the first
pump and a suction-side pump housing part of a downstream pump. It
is possible to provide a series connection without additional
components, allowing to realize a higher required maximum volume
flow. This becomes possible especially because of the irrotational
flow in the outlet port caused by the conduction device. Thus, it
is possible, in a restricted package space, to achieve a different
delivery flow with different motor sizes, without any redesigning
and without changing the components. Thereby, costs can be
reduced.
[0017] Thus, a fluid pump is provided that supplies an irrotational
flow at the outlet and operates with negligible pressure losses by
friction and the like. This increases the efficiency, since a large
part of the kinetic energy is actually converted into pressure
energy. A series connection allows to obtain various delivery rates
with the same components in a compact space.
[0018] An embodiment of the invention is illustrated in the drawing
and will be detailed hereinafter.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] The FIGURE is a side elevational sectional view of a fluid
pump according to the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0020] 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.
[0021] 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.
[0022] 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.
[0023] 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.
[0024] 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.
[0025] 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.
[0026] 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.
[0027] 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.
[0028] 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.
[0029] 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.
[0030] 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.
[0031] 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.
[0032] 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.
[0033] 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.
[0034] 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.
[0035] 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.
[0036] 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.
[0037] 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.
* * * * *