U.S. patent application number 12/093419 was filed with the patent office on 2011-07-07 for fluid pump.
This patent application is currently assigned to PIERBURG GMBH. Invention is credited to Albert Genster.
Application Number | 20110164995 12/093419 |
Document ID | / |
Family ID | 37667636 |
Filed Date | 2011-07-07 |
United States Patent
Application |
20110164995 |
Kind Code |
A1 |
Genster; Albert |
July 7, 2011 |
FLUID PUMP
Abstract
There is proposed an embodiment of an electric fluid pump of a
semi-axial design wherein support ribs (31) are arranged between a
radially outer pump housing portion (32) and a first, radially
inner motor housing portion (8) that radially surrounds the
electric motor (1), wherein the radially outer pump housing portion
(32) is formed integrally with the first motor housing portion (8)
and the support ribs (31). In this manner, as compared to
previously known embodiments, small wall thicknesses of the pump
housing can be realized because the support ribs will offer
sufficient strength. Thus, the number of component parts and the
weight can be reduced.
Inventors: |
Genster; Albert; (Neuss,
DE) |
Assignee: |
PIERBURG GMBH
Neuss
DE
|
Family ID: |
37667636 |
Appl. No.: |
12/093419 |
Filed: |
October 10, 2006 |
PCT Filed: |
October 10, 2006 |
PCT NO: |
PCT/EP2006/009761 |
371 Date: |
May 12, 2008 |
Current U.S.
Class: |
417/363 ;
417/410.1 |
Current CPC
Class: |
F04D 13/0606 20130101;
F04D 29/548 20130101; F04D 29/528 20130101; F04D 3/00 20130101 |
Class at
Publication: |
417/363 ;
417/410.1 |
International
Class: |
F04B 35/00 20060101
F04B035/00; F04B 35/04 20060101 F04B035/04 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 10, 2005 |
DE |
102005054026.0 |
Claims
1. A fluid pump for internal combustion engines, comprising: an
electric motor including a rotor arranged in a motor housing, and a
stator, wherein the rotor is arranged at least on a drive shaft for
common rotation therewith; an impeller fastened to the drive shaft;
at least one guide wheel arranged downstream of the impeller in a
flow direction of fluid to be conveyed; and a pump housing
surrounding the motor housing, the impeller and the guide wheel,
wherein the pump housing is provided with a pressure socket and an
intake socket arranged opposite the pump housing on axial ends, and
support ribs are arranged between a radially outer pump housing
portion and a first, radially inner motor housing portion that
radially surrounds the electric motor, wherein said radially outer
pump housing portion is formed integrally with said motor housing
portion and the support ribs, wherein the support ribs are shaped
so that the support ribs serve as a guide wheel of the fluid pump,
and the support ribs have a width so that an electric contact
element is guidable from an electronics unit to a stator winding
via a bore formed in one or a plurality of the support ribs.
2. The fluid pump for internal combustion engines according to
claim 1, wherein that the radially outer pump housing portion is of
a cylindrical shape.
3. The fluid pump for internal combustion engines according to
claim 1, wherein that a suction-side pump housing portion flaring
in the flow direction is formed integrally with a housing portion
of a valve arranged upstream thereof.
4. The fluid pump for internal combustion engines according to
claim 1, characterized in that the first motor housing portion is
arranged to delimit the electric motor on the suction side.
5. The fluid pump for internal combustion engines according to
claim 2, wherein a suction-side pump housing portion flaring in the
flow direction is formed integrally with a housing portion of a
valve arranged upstream thereof.
6. The fluid pump for internal combustion engines according to
claim 2, characterized in that the first motor housing portion is
arranged to delimit the electric motor on the suction side.
7. The fluid pump for internal combustion engines according to
claim 3, characterized in that the first motor housing portion is
arranged to delimit the electric motor on the suction side.
Description
[0001] This is a National Phase Application in the United States of
International Patent Application No. PCT/EP2006/009761 filed Oct.
10, 2006, which claims priority on German Patent Application No. 10
2005 054 026.0, filed Nov. 10, 2005. The entire disclosures of the
above patent applications are hereby incorporated by reference.
FIELD OF THE INVENTION
[0002] The invention relates to a fluid pump for internal
combustion engines, comprising an electric motor including a rotor
arranged in a motor housing, and a stator, the rotor being arranged
at least on a drive shaft for common rotation therewith, an
impeller fastened to the drive shaft, at least one guide wheel
arranged downstream of the impeller in the flow direction of the
fluid to be conveyed, and a pump housing surrounding the motor
housing, the impeller and the guide wheel, with a pressure socket
and an intake socket being arranged opposite the pump housing on
the axial ends, support ribs arranged between a radially outer pump
housing portion and a first radially inner motor housing portion
radially surrounding the electric motor, the radially outer pump
housing portion being formed integrally with the motor housing
portion and the support ribs.
BACKGROUND OF THE INVENTION
[0003] Fluid pumps for internal combustion engines are used
particularly as coolant pumps in a cooling circuit. While, in the
past, there existed a direct coupling to the rotational speed of
the engine and the pumps were driven with the aid of belt and chain
drives, more-recent engines are increasingly equipped with
rotational-speed-controlled coolant pumps comprising a slit tube so
as to render possible a modern heat management. Thus, excessive
conveying performance can be prevented, thus allowing e.g. for
faster warm-up of the internal combustion engine after cold
starting. The delivery volume can be controlled corresponding to
the actually required cooling performance.
[0004] A pump of the above type is known e.g. from MTZ No. 11, Vol.
2005 (pp. 872-877). The electric coolant pump is provided with an
EC motor as a drive aggregate and comprises a pump head with axial
inlet and tangential outlet. However, the components and
particularly the housing portions used in the pump are very large
in view of the power intake of the pump, thus requiring the use of
a relatively large drive motor.
[0005] Thus, disclosed in US 2002/0106290 A1 is an electric fluid
pump of a semi-axial design wherein the electric motor, although
having the same power intake, can be smaller-sized while reaching
higher rotational speeds, thus making it possible to reach the same
delivery volumes although using a pump of a smaller size. The motor
is a fully encased electric motor with a guide wheel arranged on
its outside. However, downstream of the guide wheel when seen in
the flow direction, obstacles exist which make it difficult to
effect the passage of the electric contacts to the electronics
unit. On the side of the impeller, the whole motor is sealed
towards the environment by sealing means. It is at least debatable
in how far such a sealing means will be sufficiently effective on
rotating components.
[0006] The pump housing is of a two-part design and comprises
various stepped portions and through holes for electric contacts.
Depending on the desired maximum delivery quantity, it will be
necessary to design different electric motors and housings. Due to
the relatively short guide vanes, it appears unlikely that a
complete elimination of twist can be obtained. Further, the
pressure loss caused by the passage of the electric contracts is
relatively high so that the gain with respect to the power intake
of the electric motor will be partly thwarted by the pressure
losses occurring.
[0007] From FR 2 222 885, there is known a semi-axial pump
comprising a multi-part housing of which the central portion
surrounds the electric motor and serves a one-part motor and pump
housing, wherein the pump housing is connected to the motor housing
via support ribs. Downstream of these housing portions in flow
direction, the electric contacts are guided to the outside via
additional tubes.
[0008] Known from DE 202 01 183 U1 is an axial pump which likewise
comprises a one-pieced motor and pump housing portion. Electric
contacts leading to the outside are not disclosed.
[0009] In both of the above pumps, the support ribs are of a linear
shape and thus do not serve as a guide wheel for reducing the
occurring twist. Instead, high pressure losses will occur because
the energy of the tangential component of the flow is nearly
completely converted to frictional losses.
[0010] Thus, it is an object of the invention, while keeping the
delivery volume on the same amount, to reduce the size of the pump
and thus also of the electric motor and to avoid pressure losses,
i.e. to increase the efficiency of the pump. Further, the weight of
the pump and the number of its component parts shall be
reduced.
SUMMARY OF THE INVENTION
[0011] The above object is achieved in that the support ribs have a
shape making them suitable for use as a guide wheel of the fluid
pump, and have a width allowing an electric contact element to be
guided from an electronics unit to a stator winding via a bore
formed in one or a plurality of the support ribs. In this manner,
the support ribs will take over the additional function of
converting the tangential flow component into an axial flow
component without causing higher pressure losses. The efficiency is
increased and the number of component parts is reduced. By the fact
that the electric contacts are passed through the ribs, the flow
resistance is reduced and the efficiency of the pump is increased
because of the absence of internal component parts in the flow
path. In comparison to known embodiments, it is possible to reduce
the wall thickness of the pump housing because the support ribs
will offer sufficient strength. The number of component parts and
the weight are reduced.
[0012] According to a further embodiment, the radially outer
portion of the pump housing is of a cylindrical shape so that the
connection to a suction-side pump housing portion and a
pressure-side pump housing portion can be easily established and
only slight losses will occur.
[0013] According to a particular embodiment, a suction-side pump
housing portion, flaring in the flow direction, is formed
integrally with a housing portion of a valve arranged upstream
thereof. Thus, it is rendered possible to realize a modular design
comprising upstream bypass or thermostat valves, again allowing for
a reduction of the number of component parts and the weight.
[0014] Preferably, the first portion of the motor housing is
arranged to delimit the electric motor on the suction side.
Nonetheless, production--e.g. by aluminum pressure die casting--can
be performed at low costs, again allowing for a reduced number of
component parts, keeping the risk of corrosion low and reducing the
danger of faults in assembly.
[0015] Thus, there is provided a fluid pump which has a small
number of component parts and a low weight, is easily assembled and
is less susceptible to flow losses and thus has a higher efficiency
as compared to known pumps.
[0016] An embodiment of a fluid pump of the invention is
illustrated in the drawing and will be described hereunder.
BRIEF DESCRIPTION OF THE DRAWING
[0017] The FIGURE shows a sectional lateral view of a fluid pump of
the invention.
DETAILED DESCRIPTION OF THE INVENTION
[0018] The fluid pump shown in the FIGURE, which is useful
particularly as a coolant pump in internal combustion engines, is
driven by an electronically commutated electric motor 1 comprising
a stator 2 and a rotor 4 arranged on a drive shaft 3. Arranged on
the axial end of drive shaft 3 is an impeller 5 which is of a
semi-axial design and which by its rotation will convey the
to-be-conveyed fluid, particularly a coolant, from a suction socket
6 substantially axially through the fluid pump to a pressure socket
7.
[0019] The electric motor 1 is accommodated in a motor housing
consisting of a first motor housing portion 8 on the suction side
and a second motor housing portion 9 on the pressure side.
Extending through the suction-side motor housing portion 8 is the
drive shaft 3 having the impeller 5 arranged thereon. For this
purpose, the suction-side motor housing portion 8 is formed with a
bore 10 having arranged therein a first bearing 11 for support of
drive shaft 3. Behind the first bearing 11 when viewed from the
suction side, a ceramic axial slide bearing 12 as well as a rubber
sleeve 13 and a spacer 14 are arranged. By means of this
configuration, a sufficiently vibration-damped support of the
impeller side of drive shaft 3 of electric motor 1 is obtained. The
spacer serves for extending the distance between the first bearing
11 and a second bearing 15, allowing a better compensation for an
angle error when forming the bore 10 for accommodating the
bearings. Again downstream of spacer 14, a rotor plate pack 16 is
arranged on the shaft, which pack is formed with axial slits for
accommodating magnets 17 which cooperate with a stator coil 18 in a
known manner. The rotor 4 is axially and radially delimited by a
capsule 19. The stator coil 18 is wound onto an insulating body 20
and delimits a stator plate pack 21 in a known manner. For closing
the magnetic circuit, the stator plate pack 21 is connected in a
form-closed manner to a magnetic-yoke 22. The magnetic-yoke 22 is
arranged to bear against an abutment portion 23 formed on an inner
face of the first, suction-side motor housing portion 8.
[0020] Rotor 4 is separated from stator 2 by a slit tube 24 which
on the suction side of the pump is arranged to rest in a
corresponding receiving opening 25 of the suction-side motor
housing portion 8 and which has also its opposite axial end
arranged in a corresponding receiving opening 26 of the
pressure-side motor housing portion 9. Thus, the stator 2 with its
sensitive coil 18 is arranged in a dry space which is separated by
the two motor housing portions 8 and 9 and by the slit tube 24.
[0021] Provided on the pressure-side end of the slit tube 24 is a
closure member 27 having arranged therein the second bearing 15 for
supporting the drive shaft 3. Axially, the closure member 27 is
secured by the pressure-side motor housing portion 9 which with an
interposed sealing member 28 is arranged in an accommodating
opening 29 of the suction-side motor housing portion 8.
[0022] The contacting of the stator coil 18 is effected via a bore
30 in a radial direction through the pressure-side motor housing
portion 9. To avoid possible flow losses caused by such additional
inserts as has been known in the state of the art, the bore is
passed through support ribs 31 which are required for sufficient
strength and attachment of a pump housing. For this purpose, the
support ribs 31 have a sufficient width and are arranged in a sort
of airfoil configuration so as to preclude a narrowing of the cross
section. Via this bore 30, it is now possible to guide an electric
contact element, not illustrated, to an electronics unit, also not
illustrated, for the controlling of motor 1.
[0023] In the illustrated embodiment, the support ribs 31 are
formed to the effect that they also serve as a guide wheel, thus
obviating the need for an additional guide wheel directly behind
impeller 5. This makes it possible to produce the suction-side
motor housing portion 8 together with the support ribs and a
cylindrical, radially outer pump housing portion 32 in a simple
manner as one integral unit. The pump housing portion 32 surrounds
the radial inner motor housing portion 8 as well as the complete
electric motor 1.
[0024] On the downstream and the upstream side of the housing
portion 8,31,32, two identical pump housing portions 33,34 are
fastened by a screw connection, each time with an interposed
sealing means 50. The suction-side pump housing portion 33, flaring
in the flow direction, comprises the suction socket 6 configured as
a cylindrical portion 35 with an adjoining flaring portion 36. In
the transition region 37 between the first portion 35 and the
second portion 36, the semi-axial impeller 5 of the fluid pump is
arranged. In the present embodiment, the flaring portion 36 is
adjoined by a further, short cylindrical portion 38 of a larger
diameter to provide for a smooth transition to the cylindrical pump
housing portion 32.
[0025] Also the pressure-side pump housing portion 34 comprises
corresponding portions narrowing in the flow direction, as well as
cylindrical portions; due to the identity of these component parts,
they are provided with the same reference numerals.
[0026] Further, the identical pump housing portions 33,34 are
formed with grooves 39 engaged by radial ends 40 of return vanes
41. These return vanes 41 serve as a post-guidance structure 42
which is effective to generate a completely twist-free flow behind
the pressure socket 7. The post-guidance structure 42 is formed on
a surface 43 of the pressure-side motor housing portion 9 and
becomes necessary because the support ribs 31 serving as a guide
wheel are relatively short and a complete reduction of the twist
will normally not be accomplished in this region of the fluid pump.
Further, the pressure-side motor housing portion 9 can be produced
from plastic while the suction-side motor housing portion should,
if possible, be produced from aluminum and thus is expensive. If
the guide wheel were arranged in this region, this would
necessitate a relatively expensive production process whereas the
manufacture of the post-guidance structure on the plastic housing
portion 9 is simple and inexpensive.
[0027] The grooves 39 are also effective to define the position of
the pressure-side pump housing portion 34 relative to the
pressure-side motor housing portion 9. When, during the assembly of
the pump, the screws are tightened for fastening the pressure-side
pump housing portion 34 to the cylindrical pump housing portion 32,
the pressure-side pump housing portion 34 will press the motor
housing portion 9 via the return vanes 40 against the motor housing
portion 8 and respectively into the accommodating openings 29 of
motor housing portion 8. Further, thereby, the motor housing
portion 9 will be pressed against the closure member 27 and
respectively against the split tube 24 so that no additional
attachment of the two motor housing portions 8,9 will be
required.
[0028] During operation of the pump, the rotation of impeller 5
comprising a plurality of impeller vanes 44 has the effect that the
to-be-conveyed fluid or particularly coolant will be conveyed
through the space between the pump housing 32,33,34 and the motor
housing 8 and 9, and will then be conveyed past the support ribs 31
where--due to their function as a guide wheel--already a part of
the twist will be eliminated from the flow, and will further be
conveyed via the post-guidance structure 42 wherein the flow will
be completely freed of the existing twist, so that the applied
energy can be as largely as possible converted into pressure energy
and thus into an axial flow without occurrence of frictional
losses.
[0029] Behind impeller 5, part of the fluid will flow through bores
45 formed in the suction-side motor housing portion 8. A further
part of the fluid will flow behind impeller 5 all the way to the
drive shaft 3 and, in this region, onward between the first bearing
11 and the drive shaft 3 so that the existing slide bearing will
receive sufficient lubrication. Thus, coolant liquid has reached
the rotor space, which coolant in turn will be passed on--between
drive shaft 3 and second bearing 15 and via non-visible bores of
closure member 27--into a space 46 axially downstream thereof. The
space 46 is connected, via a further bore 47 axially extending
through the pressure-side motor housing portion 9, to the space
arranged therebehind. Thus, what is accomplished is a lubrication
of the bearings 11,15 as well as a possibility for cooling and for
discharge of possible air quantities in the rotor space.
[0030] This semi-axial pump is distinguished particularly by the
possibility to give it a quite small constructional size because,
in comparison to known pumps, it is rendered possible, on the basis
of the same power input, to obtain the same delivery rate with a
reduced motor size and increased rotational speed. This is
accomplished particularly by the extremely reduced pressure losses
in such a construction; also, however, by the semi-axial
design.
[0031] Further, a pump of the above type is very inexpensive in
production because there is involved a reduced number of different
constructional parts. This will in turn reduce possible errors in
the assembly process. Due to the absence of an additional guide
wheel and due to the integration of the electric contacts into the
support ribs, the need for additional constructional parts is
avoided and pressure losses are reduced. Generally, thus, a higher
efficiency is reached.
[0032] Of course, the simple configuration of the pump housing
portions 33,34 offers the possibility to provide them with a flange
arranged on the pressure socket and the suction socket,
respectively. This makes it possible, on the one hand, to establish
a direct connection to the motor housing or, on the other hand, to
switch a plurality of pumps in series so as to increase the
conveyed fluid volume. This is made possible especially by the
twist-free flow effected by the post-guidance structure 42,
allowing the flow to be passed directly to the impeller 5 of a
downstream pump without occurrence of energy losses. Thus, in cases
where twice the usual performance is required, it will not be
necessary to build a larger pump which in turn would have a larger
motor; instead, because of the similarity of the component parts,
it is possible to simply arrange the corresponding required number
of pumps in series.
[0033] Further, because of the simple design particularly of the
suction-side pump housing portion 33, the possibility exists to
produce the latter integrally with valve housing portions so that
the pump housing portion 33 can comprise e.g. a receiving portion
to accommodate a bypass or an integrated thermostat valve. Also
parts of the housing of a sliding cylindrical valve can be produced
integrally with the suction-side pump housing portion 33.
[0034] It is understood that the illustrated exemplary embodiment
represents merely one possible realization of the invention and
that various aspects of the design of this embodiment can be
modified without leaving the protective scope of the claims.
* * * * *