U.S. patent application number 10/933485 was filed with the patent office on 2006-01-12 for high-speed impeller.
Invention is credited to Johann Kramer, Martin Schlegl, Erwin Schmidt, Holger Stark, Siegfried Sumser.
Application Number | 20060008354 10/933485 |
Document ID | / |
Family ID | 34129698 |
Filed Date | 2006-01-12 |
United States Patent
Application |
20060008354 |
Kind Code |
A1 |
Kramer; Johann ; et
al. |
January 12, 2006 |
High-speed impeller
Abstract
The invention relates to a high-speed impeller for delivering
gaseous or liquid media, for example as a compressor wheel for an
exhaust-gas turbocharger. The high-speed impeller has a reinforcing
core structure and an outer functional section. The invention is
distinguished by the fact that reinforcing sleeves are pushed
concentrically over one another for producing the core structure,
in which case the length of the respective reinforcing sleeves
varies. Furthermore, the functional section is cast onto the core
structure.
Inventors: |
Kramer; Johann; (Leonberg,
DE) ; Schlegl; Martin; (Rudersberg, DE) ;
Schmidt; Erwin; (Baltmannsweiler, DE) ; Stark;
Holger; (Tettnang, DE) ; Sumser; Siegfried;
(Stuttgart, DE) |
Correspondence
Address: |
CROWELL & MORING LLP;INTELLECTUAL PROPERTY GROUP
P.O. BOX 14300
WASHINGTON
DC
20044-4300
US
|
Family ID: |
34129698 |
Appl. No.: |
10/933485 |
Filed: |
September 3, 2004 |
Current U.S.
Class: |
416/244R |
Current CPC
Class: |
F04D 29/284 20130101;
F01D 5/048 20130101 |
Class at
Publication: |
416/244.00R |
International
Class: |
D02G 3/02 20060101
D02G003/02 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 5, 2003 |
DE |
10341415.0 |
Claims
1. A high-speed impeller for delivering gaseous or liquid media,
having a reinforcing core structure and an outer functional
section, wherein a plurality of reinforcing sleeves are pushed
concentrically over one another for producing the core structure,
in which case a length of each of the respective reinforcing
sleeves varies, and the functional section is cast onto the core
structure.
2. The high-speed impeller as claimed in claim 1, wherein the
length of each of the respective reinforcing sleeves is reduced
with increasing outside diameter.
3. A high-speed impeller for delivering gaseous or liquid media,
having a reinforcing core structure and an outer functional
section, wherein a plurality of reinforcing sleeves with in each
case inner bores having the same diameter are concentrically
aligned on a common axis, the outside diameters of the reinforcing
sleeves vary for reproducing a predetermined cross-sectional
geometry of the core structure, and the functional section is cast
onto the core structure.
4. The high-speed impeller as claimed in claim 3, wherein the
reinforcing sleeves with the aligned inner bores are concentrically
pushed onto a center reinforcing sleeve whose outer diameter
corresponds to the diameter of the inner bores of the same
kind.
5. The high-speed impeller as claimed in claim 1, wherein the
reinforcing sleeves comprise a fiber-reinforced material.
6. The high-speed impeller as claimed in claim 3, wherein the
reinforcing sleeves comprise a fiber-reinforced material.
7. The high-speed impeller as claimed in claim 5, wherein the
reinforcing sleeves have a long-fiber-reinforced wound body.
8. The high-speed impeller as claimed in claim 6, wherein the
reinforcing sleeves have a long-fiber-reinforced wound body.
9. The high-speed impeller as claimed in claim 1, wherein the
reinforcing sleeves consist of a metal-matrix composite material
reinforced with short fibers.
10. The high-speed impeller as claimed in claim 3, wherein the
reinforcing sleeves consist of a metal-matrix composite material
reinforced with short fibers.
11. The high-speed impeller as claimed in claim 1, wherein the
reinforcing sleeves consist of a metal-infiltrated porous
ceramic.
12. The high-speed impeller as claimed in claim 3, wherein the
reinforcing sleeves consist of a metal-infiltrated porous
ceramic.
13. The high-speed impeller as claimed in claim 1, wherein the
reinforcing sleeves consist of a spray-compacted metal
material.
14. The high-speed impeller as claimed in claim 3, wherein the
reinforcing sleeves consist of a spray-compacted metal
material.
15. The high-speed impeller as claimed in claim 1, wherein the
reinforcing sleeves consist of a high strength wrought alloy.
16. The high-speed impeller as claimed in claim 3, wherein the
reinforcing sleeves consist of a high strength wrought alloy.
17. The high-speed impeller as claimed in claim 1, wherein the
high-speed impeller is a compressor wheel or a turbine wheel of an
exhaust-gas turbocharger.
18. The high-speed impeller as claimed in claim 3, wherein the
high-speed impeller is a compressor wheel or a turbine wheel of an
exhaust-gas turbocharger.
19. A method of forming a high speed impeller for delivering
gaseous or liquid media, comprising the steps of: arranging a
plurality of concentric reinforcing sleeves over one another to
produce a core structure, wherein a length of each of the
respective reinforcing sleeves varies; and casting a functional
section onto the core structure.
20. A method of forming a high speed impeller for delivering
gaseous or liquid media, comprising the steps of concentrically
aligning on a common axis the inner bores of a plurality of
reinforcing sleeves, wherein the inner bores of each of the
reinforcing sleeves have the same diameter, and the outside
diameters of the reinforcing sleeves vary, such that a core
structure of a predetermined cross-sectional geometry is produced;
and casting a functional section onto the core structure.
Description
[0001] This application claims the priority of 103 41 415.0, filed
Sep. 5, 2003, the disclosure of which is expressly incorporated by
reference herein.
BACKGROUND AND SUMMARY OF THE INVENTION
[0002] The invention relates to a high-speed impeller for
delivering gaseous or liquid media.
[0003] DE 101 63 951 C1 describes a rotor disk which is made of a
metal and has local fiber reinforcements. In this case, the fiber
reinforcements consist of metal matrix composites (MMC). These
inner MMC rings are pressed into the circumference of the rotor
disk by means of a radial press fit.
[0004] A rotor consisting of a composite material is described in
WO 02/01311 A1, various rings of fiber-reinforced wound bodies
being slipped concentrically over one another and thus forming a
flat cylindrical rotor disk.
[0005] Said examples show methods of reinforcing an impeller
subjected to high centrifugal loading. However, the arrangements
described have the disadvantage that complex impeller structures
cannot be reproduced or the fiber reinforcements are not fully
integrated in the impeller.
[0006] An object of the invention includes providing a high-speed
impeller which has an integrated reinforcement in a complex
cross-sectional contour.
[0007] A solution of this object includes a high-speed impeller in
which a reinforcing core structure is surrounded by an outer
functional section, and reinforcing sleeves are pushed
concentrically over one another for producing the core structure.
In this case, "pushed concentrically over one another" refers to
the fact that the outside diameter of an inner reinforcing sleeve
equals an inside diameter of an outer reinforcing sleeve to the
extent that the outer reinforcing sleeve can be pushed with little
play over the inner reinforcing sleeve.
[0008] In this case, the length of the respective reinforcing
sleeve varies in such a way that it can approximately reproduce a
predetermined cross-sectional geometry of the core contour.
[0009] Due to such a construction of the core structure, a
reinforcement of the impeller can be produced which, in deviation
from the cylindrical structure of the reinforcements which are
mentioned in the prior art, is designed, for example, in hyperbolic
shape or in a rising exponential manner. The reinforcement is
therefore not only settled in a narrow cylindrical region, but it
can also be adapted along a complex cross-sectional structure of
the high-speed impeller.
[0010] In many cases, the cross-sectional geometry of the
high-speed impeller narrows with increasing diameter, for which
reason it is expedient that, in a development of the invention, the
length of the reinforcing sleeves is reduced with increasing
outside diameter.
[0011] A further aspect of the invention constitutes a high-speed
impeller which, claim 3. Such a high-speed impeller, like
previously mentioned the high-speed impeller, has a reinforcing
core structure which is surrounded by an outer functional section.
However, this embodiment of the high-speed impeller is
distinguished by the fact that, in order to produce the core
structure, a plurality of reinforcing sleeves with in each case
inner bores having the same diameter are aligned in such a way that
the inner bores are aligned congruently. The expression
"congruently" in this case refers to the fact that the inner bores
are concentrically aligned on a common axis in such a way that a
shaft can be pushed with little play through the aligned
arrangement of the inner bores. However, the outside diameter of
the aligned reinforcing sleeves varies in order to reproduce a
predetermined cross-sectional geometry of the core structure. The
functional section of the high-speed impeller is likewise cast onto
the core structure.
[0012] By the arrangement of the reinforcing sleeves being
modified, the high-speed impeller according to this latter
embodiment achieves the same advantages as are also described by
the arrangement of the high-speed impeller as in the
first-described embodiment.
[0013] As described, the aligned arrangement of the reinforcing
sleeves having the congruently superimposed inner bores can be
pushed onto a shaft; however, it can also be pushed onto a
reinforcing sleeve of the same kind. In this way, additional radial
and axial strengthening is achieved.
[0014] In an advantageous development of the invention, the
reinforcing sleeves are produced from a fiberreinforced material.
Any form of fiber-reinforced materials by means of which a marked
increase in the tensile strength and thus a marked increase in the
strength of the high-speed impeller is achieved is suitable in this
case. In a further development, the reinforcing sleeves comprise
long-fiber-reinforced wound bodies. Such wound bodies may either
already be infiltrated with a metal before the integral casting of
the functional section, or they may be infiltrated with the metal
of the functional section during the integral acasting of the
functional section.
[0015] Furthermore, the reinforcing sleeves may consist of a
metal-matrix composite material reinforced with short fibers.
Furthermore, a porous ceramic infiltrated by metal may be used for
the reinforcing sleeves. An increase in the tensile strength and in
the modulus of elasticity is also achieved by such reinforcing
sleeves.
[0016] It may also be expedient to produce the reinforcing sleeves
from non-fiber-reinforced, high-strength metal materials, for
example from spray-compacted metal materials or from high-strength
wrought alloys. As a rule, such materials can be produced more
cost-effectively than fiber-reinforced materials and are used when
there is little latitude in terms of the cost of the component.
[0017] The use of the high-speed impeller according to the
invention is in particular especially expedient in exhaust-gas
turbochargers, in this case equally as a compressor wheel or a
turbine wheel. The impellers may also be used in an expedient
manner as gas turbine wheels or as water pump wheels.
[0018] Other objects, advantages and novel features of the present
invention will become apparent from the following detailed
description of the invention when considered in conjunction with
the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] FIG. 1 shows a graphic illustration of a compressor impeller
of an exhaust-gas turbocharger,
[0020] FIG. 2 shows a schematic illustration of a core structure
with reinforcing sleeves pushed over one another in accordance with
an exemplary embodiment of the present invention.
[0021] FIG. 3 shows a schematic illustration of a core structure
with aligned reinforcing sleeves having a constant inside diameter,
the aligned arrangement being pushed concentrically onto a
reinforcing sleeve of the same kind,
[0022] FIG. 4 shows a schematic illustration of a core structure
with aligned reinforcing sleeves which each have an identical
inside diameter,
[0023] FIG. 5 shows a schematic illustration of a core structure
with aligned reinforcing sleeves which each have an identical
inside diameter.
DETAILED DESCRIPTION
[0024] A schematic illustration of a high-speed impeller in the
form of a compressor wheel 2 for an exhaust-gas turbocharger is
shown in FIG. 1. This compressor wheel 2 has a functional section 6
which comprises, for example, compressor blades 7. Furthermore, the
compressor wheel 2 comprises a core structure 4 which, starting
from a concentric region around a bore 9 in the center of the
compressor wheel 2, runs outward with increasing diameter and is
designed as a support structure of the compressor blades 7.
[0025] For the sake of clarity, only a cross section of the core
structure is shown in FIGS. 2 to 5. The illustration of the
functional section 6 having the compressor blades 7 is dispensed
with.
[0026] Shown in FIG. 2 is a core structure 4 which is produced from
a plurality of reinforcing sleeves 8 which are pushed over one
another concentrically. For the sake of clarity, only two
reinforcing sleeves 8 are provided with the corresponding reference
numerals, corresponding designations being provided with the same
reference numerals.
[0027] The reinforcing sleeves 8 have an outside diameter 12 and an
inside diameter 14. In this case, the outside diameter 12 of each
reinforcing sleeve 8 is configured in such a way that it
corresponds to the inside diameter 14 of the following reinforcing
sleeve 8 to the extent that the two reinforcing sleeves 8 can be
pushed over one another with little play (cf. FIG. 2, right-hand
side). In this case, in the example according to FIG. 2, the
reinforcing sleeves 8 become shorter from the inside outward; that
is to say the length 10 of the reinforcing sleeves 8 decreases from
the inside outward. If need be, for reproducing the cross section
of the core structure 4, a wall thickness 13 may also vary from one
reinforcing sleeve 8 to the next reinforcing sleeve 8.
[0028] The result of such a type of construction is shown
schematically in FIG. 2 on the left-hand side. Indicated by the
dot-dash line, the cross-sectional geometry of the reinforcing
structure 4 runs outward in a similar manner to an exponential
curve until it reaches a maximum value in order to then fall away
again roughly in a hyperbolic shape in the direction of a center
axis 16. In this case, a plan view of the core structure 4 is
depicted in the top part of the lefthand sketch in FIG. 2, and a
section through the core structure 4 is shown in the bottom part of
the sketch.
[0029] The core structure 4 from FIG. 3 differs from the core
structure 4 in FIG. 2 in that reinforcing sleeves 20 which each
have an inner bore 22 of identical diameter are provided. The
reinforcing sleeves 20 are aligned in such a way that the inner
bores 22 are congruently superimposed, a reinforcing sleeve 26 of
the same kind being shown in such a way that its outside diameter
28 can be pushed with little play into the inner bores 22 of the
reinforcing sleeves 20. The reinforcing sleeves 20 are therefore
aligned on the reinforcing sleeve 26 of the same kind. According to
the example from FIG. 3, the reinforcing sleeves 20 likewise have a
different length 10. By means of this measure, the predetermined
cross-sectional geometry of the core structure 4, which is shown by
the dot-dash line in FIG. 3 in the sketch on the left-hand side,
can be filled as fully as possible.
[0030] An aligned arrangement of various sleeves 20, with in each
case a constant inner bore 22, is shown in the example in FIG. 4,
which is similar to the example from FIG. 3. The difference from
FIG. 3 consists in the fact that a reinforcing sleeve 26 of the
same kind, onto which the aligned arrangement of the reinforcing
sleeves 20 is pushed, is not used here. The aligned arrangement of
reinforcing sleeves 20 in FIG. 4 can be soldered, adhesively bonded
or stitched, for example, depending on which materials are used for
the reinforcing sleeves 20. The aligned arrangement of reinforcing
sleeves 20 can then be pulled onto a shaft.
[0031] An aligned arrangement of reinforcing sleeves 20, similar to
the example from FIG. 4, is likewise shown in FIG. 5. This involves
a simplified form, since the reinforcing sleeves 20 essentially
have the same length. As can be seen in the sketch on the left-hand
side of FIG. 5, the cross-sectional geometry of the reinforcing
structure 4 is not filled to the optimum extent, as occurs, for
example, by means of the exemplary embodiment in FIG. 4. However,
such a simpler, cost-effective type of construction may be
advantageous for simple compressor wheels which are not subjected
to very high loading.
[0032] The types of construction of the reinforcing structure 4
which are shown in FIGS. 2 to 5 involve comparatively complex
arrangements. In practice, it may therefore often be expedient for
reasons of cost for only two _einforcing sleeves 8 to be pushed
concentrically over one another according to the example from FIG.
2. It may also be expedient, for example, in accordance with FIG.
3, for only two reinforcing sleeves 20 to be aligned and for said
reinforcing sleeves 20 to be pulled onto a reinforcing sleeve 26 of
the same kind or for them to be pushed directly onto a shaft (not
shown here). In this case, the existing loading condition at the
compressor wheel 2 and the cost framework are to be taken into
account in each case.
[0033] The materials which are used for producing the reinforcing
sleeves 8 or 20 are likewise adapted to the mechanical stresses
which act on the compressor wheel 2. The production of the
reinforcing sleeves from a fiber-reinforced material has been found
to be expedient.
[0034] A possible example for the production of a reinforcing
sleeve 8 or 20 consists in producing a wound body of long-fiber
material or of spun short-fiber material. In this case, the fibers
are impregnated in a wax, resin or polymer. The impregnated
material hardens after the wound body has been wound up, thereby
resulting in "preforms" of the reinforcing sleeves 8, 20. These
preforms of the reinforcing sleeves 8, 20 can be cut into segments
having the desired lengths 10, in which case these segments,
according to the mode of expression used here, may already be
referred to as reinforcing sleeves 8, 20. These reinforcing sleeves
8, 20 can be attached to one another or pushed over one another,
for example, by adhesive bonding, pressing, stitching, stacking or
hot melting. Thus preliminary fixing already exists and already
represents the cross-sectional geometry of the core structure
4.
[0035] Organic material such as wax or polymer is then melted or
the resin or the polymer or the wax is burnt out of the reinforcing
sleeves 8, 20. The reinforcing sleeves 8, 20, which are thus free
of organic bonding agents, are placed in a casting mold and are
infiltrated during the pouring with the metal melt, which also
subsequently forms the functional section 6. In this case, a
die-casting or a squeeze-casting process is expedient. If
appropriate, the burning-out and the pouring of the metal melt can
also be effected at the same time.
[0036] In another variant of the method of producing the core
structure 4, fiber-reinforced wound bodies, which are inflitrated
with polymers or resins or waxes, are produced in a similar manner
to the preceding example and are assembled to form a core structure
4 similar to FIGS. 2 to 5, the organic material--wax, resin or
polymer--is removed, and the core structure 4 is infiltrated with a
special metal in a corresponding casting process, for example a
die-casting process. The core structure 4 infiltrated in this way
is then encapsulated with the functional section 6 in the precision
casting or in another low-pressure casting process.
[0037] In the casting process described last, it may be expedient
to provide the already pre-infiltrated core structure 4 with an
adhesion layer so that the liquid metal adheres more effectively to
the core structure during the integral casting of the functional
section 6 and thus forms a firm bond.
[0038] In the cases in which the fiber wound body is infiltrated
with liquid metal, it may possibly be expedient to coat the fibers,
so that, on the one hand, a reaction of the infiltration metal with
the fiber is avoided and, on the other hand, better wetting and
better infiltration is ensured.
[0039] For reasons of cost, when less stringent mechanical demands
are made on the compressor wheels 2 or in general on the high-speed
impeller to be produced, the reinforcing sleeves may be produced,
for example, from a wrought alloy, in particular an aluminum
wrought alloy. The use of metal-matrix composites, which if
appropriate are reinforced with short fibers, or the use of
spray-compacted metallic materials may be expedient for the
reinforcing sleeves 8, 20.
[0040] The foregoing disclosure has been set forth merely to
illustrate the invention and is not intended to be limiting. Since
modifications of the disclosed embodiments incorporating the spirit
and substance of the invention may occur to persons skilled in the
art, the invention should be construed to include everything within
the scope of the appended claims and equivalents thereof.
* * * * *