U.S. patent application number 14/060212 was filed with the patent office on 2014-07-03 for guide blade arrangement for an exhaust gas turbocharger.
This patent application is currently assigned to Bosch Mahle Turbo Systems GmbH & Co. KG. The applicant listed for this patent is Bosch Mahle Turbo Systems GmbH & Co. KG. Invention is credited to Dirk Naunheim.
Application Number | 20140186171 14/060212 |
Document ID | / |
Family ID | 50437058 |
Filed Date | 2014-07-03 |
United States Patent
Application |
20140186171 |
Kind Code |
A1 |
Naunheim; Dirk |
July 3, 2014 |
GUIDE BLADE ARRANGEMENT FOR AN EXHAUST GAS TURBOCHARGER
Abstract
A guide blade arrangement for an exhaust gas turbocharger may
include guide blades rotatably mounted on a guide blade carrier
ring via a respective blade bearing pin. A cover disc may be spaced
from the guide blade carrier ring, wherein the guide blades may be
arranged between the cover disc and the guide blade carrier ring.
The cover disc may include a ceramic material, and the ceramic
material may have a higher thermal conductivity in relation to at
least one of the guide blade carrier ring, the guide blades, and
the respective blade bearing pin.
Inventors: |
Naunheim; Dirk; (Stuttgart,
DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Bosch Mahle Turbo Systems GmbH & Co. KG |
Stuttgart |
|
DE |
|
|
Assignee: |
Bosch Mahle Turbo Systems GmbH
& Co. KG
Stuttgart
DE
|
Family ID: |
50437058 |
Appl. No.: |
14/060212 |
Filed: |
October 22, 2013 |
Current U.S.
Class: |
415/208.1 |
Current CPC
Class: |
F01D 17/165 20130101;
F02B 37/24 20130101; F05D 2300/50211 20130101; F05D 2220/40
20130101; F05D 2300/2283 20130101; F05D 2300/2261 20130101; F05D
2300/5024 20130101; F01D 9/02 20130101 |
Class at
Publication: |
415/208.1 |
International
Class: |
F01D 9/02 20060101
F01D009/02 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 23, 2012 |
DE |
102012219355.3 |
Claims
1. A guide blade arrangement for an exhaust gas turbocharger,
comprising: guide blades rotatably mounted on a guide blade carrier
ring via a respective blade bearing pin, a cover disc that is
spaced from the guide blade carrier ring, wherein the guide blades
are arranged between the cover disc and the guide blade carrier
ring, wherein the cover disc includes a ceramic material, and
wherein the ceramic material has a higher thermal conductivity in
relation to at least one of the guide blade carrier ring, the guide
blades, and the respective blade bearing pin.
2. The guide blade arrangement according to claim 1, wherein the
ceramic material has a thermal conductivity of at least 120
W/mK.
3. The guide blade arrangement according to claim 1, wherein the
ceramic material is one of silicon nitride and silicon carbide.
4. The guide blade arrangement according to claim 1, wherein at
least one of the guide blade carrier ring, the guide blades, and
the blade bearing pins are produced from a metal which has a lower
thermal conductivity than the thermal conductivity of the ceramic
material.
5. The guide blade arrangement according to claim 4, wherein the
metal has a maximum thermal conductivity of 20 W/mK.
6. The guide blade arrangement according to claim 4, wherein the
metal is a steel.
7. The guide blade arrangement according to claim 1, wherein the
cover disc is formed entirely of the ceramic material.
8. The guide blade arrangement according to claim 1, further
comprising at least one spacer element, which is arranged coaxially
to the blade bearing pin and holds the guide blade carrier ring
spaced from the cover disc.
9. An exhaust gas turbocharger for a motor vehicle, comprising: a
guide blade arrangement including: guide blades rotatably mounted
on a guide blade carrier ring via a respective blade bearing pin, a
cover disc that is spaced from the guide blade carrier ring,
wherein the guide blades are arranged between the cover disc and
the guide blade carrier ring, wherein the cover disc includes a
ceramic material, the ceramic material having a higher thermal
conductivity in relation to at least one of the guide blade carrier
ring, the guide blades, and the respective blade bearing pin, a
turbine housing with a housing wall facing the guide blade
arrangement, on which the cover disc of the guide blade arrangement
is arranged, a bearing housing and a spring element supporting
itself on the bearing housing, wherein in the axial direction a
pressure force is exerted on at least one spacer element via the
guide blade carrier ring, said spacer element configured to push
the cover disc against the turbine housing for axial fixing.
10. (canceled)
11. The guide blade arrangement according to claim 2, wherein the
ceramic material is one of silicon nitride and silicon carbide.
12. The guide blade arrangement according to claim 1, wherein the
guide blade carrier ring, the guide blades, and the blade bearing
pins are produced from metal which has a lower thermal conductivity
than the thermal conductivity of the ceramic material.
13. The guide blade arrangement according to claim 3, wherein at
least one of the guide blade carrier ring, the guide blades, and
the blade bearing pins are produced from metal which has a lower
thermal conductivity than the thermal conductivity of the ceramic
material.
14. The guide blade arrangement according to claim 5, wherein the
metal is steel.
15. The guide blade arrangement according to claim 12, wherein the
metal is steel.
16. The guide blade arrangement according to claim 1, wherein the
cover disc is formed entirely of ceramic material.
17. The turbocharger according to claim 9, wherein the ceramic
material has a thermal conductivity of at least 120 W/mK.
18. The turbocharger according to claim 9, wherein the ceramic
material is one of silicon nitride and silicon carbide.
19. The turbocharger according to claim 9, wherein at least one of
the guide blade carrier ring, the guide blades, and the blade
bearing pins are produced from a metal which has a lower thermal
conductivity than the thermal conductivity of the ceramic
material.
20. The turbocharger according to claim 19, wherein the metal has a
maximum thermal conductivity of 20 W/mK.
21. The turbocharger according to claim 9, wherein the cover disc
is formed entirely of the ceramic material.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority to German Patent
Application No. 10 2012 219 355.3 filed Oct. 23, 2012, which is
hereby incorporated by reference in its entirety.
TECHNICAL FIELD
[0002] The present invention relates to a guide blade arrangement,
in particular for an exhaust gas turbocharger, and to an exhaust
gas turbocharger having such a guide blade arrangement. The
invention furthermore relates to a motor vehicle having such an
exhaust gas turbocharger.
BACKGROUND
[0003] As is known, exhaust gas turbochargers for internal
combustion engines consist of two continuous-flow machines: on the
one hand of a turbine, on the other hand of a compressor. The
turbine utilises the energy contained in the exhaust gas for
driving the compressor, which draws in fresh air and introduces
compressed air into the cylinders of the internal combustion
engine. Because of the usually very high rotational speed range of
the internal combustion engine, regulating the exhaust gas
turbocharger is required so that as constant as possible a charge
pressure in as large as possible a rotational speed range of the
internal combustion engine can be ensured. To this end, solutions
are known according to which a part of the exhaust gas flow is
guided about the turbine by means of a bypass channel. An
energetically more favourable solution however is made possible by
the so-called variable turbine geometry, in which the accumulation
behaviour of the turbine is continuously changed and thus the
entire exhaust gas can be utilised in each case. Such a variable
turbine geometry is realised in the conventional manner by means of
adjustable guide blades, by means of which the desired exhaust gas
flow flowing through an exhaust gas turbocharger can be variably
adjusted.
[0004] For adjusting the guide blades, different adjusting
mechanisms are known. Usually, the guide blades are mounted on a
guide blade carrier ring via a respective blade bearing. Spaced
from the guide blade carrier ring, a cover disc is arranged, so
that the guide blades are arranged between this cover disc and the
guide blade carrier ring. The cover disc can be produced from a
ceramic material.
[0005] DE 10 2008 039 508 A1 describes a charging device of an
exhaust gas turbocharger with a variable turbine geometry. The
charging device comprises a blade bearing ring with guide blades
rotatably mounted thereon. On a side of the guide blades located
opposite the blade bearing ring, an annular disc for covering the
guide blades is provided. The annular disc comprises a
heat-insulating and friction-reducing material.
SUMMARY
[0006] It is an object of the present invention to state an
improved embodiment for a guide blade arrangement.
[0007] This object is solved through the subject of the independent
claims. Preferred embodiments are subject of the dependent
claims.
[0008] The invention is based on the general idea of using a
ceramic material for the cover disc of the guide blade arrangement,
which has a high thermal conductivity. In this way, heat occurring
in the guide blade arrangement can be quickly and effectively
discharged, so that the temperature loading of a turbine housing,
in which the guide blade arrangement according to the invention can
be employed, can be significantly reduced.
[0009] Ceramics with a high thermal conductivity are largely
objects which are shaped from anorganic, fine-grained raw materials
with the addition of water at room temperature and which are dried
thereafter, which in a subsequent burning process above 900.degree.
C. are sintered into hard, durable objects. Ceramic materials can
have a very high thermal conductivity, as a result of which they
are particularly predestined for the use of a cover disc of a guide
blade arrangement of an exhaust gas turbocharger according to the
invention. In addition, ceramic materials are also able to
withstand high temperatures, such as occur in such an exhaust gas
turbocharger, over long periods of time. Ceramic materials or
coatings can be produced cost-effectively and in almost any
embodiment, as a result of which an economical industrial use is
possible.
[0010] In particular, by using ceramic materials with high thermal
conductivity, a thermally-induced expansion of individual
components of the guide blade arrangement or of the exhaust gas
turbocharger using the guide blade arrangement can be avoided. This
in turn allows reducing a gap width between the guide blades and
the cover disc in size, since through the use of a cover disc with
high thermal conductivity according to the invention it is ensured
that a heat-induced, undesirable thermal expansion of the guide
blades is avoided, so that no thermally-induced friction effects
between the guide blades and the cover disc (up to a jamming of the
guide blades) can occur.
[0011] Since the cover disc according to the invention thus makes
possible a minimal gap width between the guide blades and the cover
disc, a bypass flow through such a gap which lowers the efficiency
of the guide blade arrangement or of the exhaust gas turbocharger
using this guide blade arrangement can be reduced or even
completely eliminated, which significantly improves the efficiency
of the guide blade arrangement or of the exhaust gas
turbocharger.
[0012] In an advantageous further development of the solution
according to the invention, the ceramic material can have a thermal
conductivity of at least 120 W/mK. By using a ceramic material with
such a high thermal conductivity, (waste) heat can be discharged
out of the guide blade arrangement in a particularly favourable
manner.
[0013] In a particularly preferred embodiment, the ceramic material
can be silicon nitride or silicon carbide. Silicon carbide is a
ceramic compound of silicon and carbon belonging to the group of
carbides. Since silicon carbide has a high mechanical hardness and
on the other hand a very high thermal conductivity (pure silicon
carbide: approx. 350 W/mK, technical silicon carbide: up to 140
W/mK), it is particularly well suited as ceramic material for the
cover disc of the guide blade arrangement according to the
invention.
[0014] Similar is true for silicon nitride, which in addition to
its high strength is also characterized by a very low thermal
expansion coefficient and a small modulus of elasticity. Ceramics
of silicon nitride can be employed at temperatures of up to
approximately 1,300.degree. C. and are therefore particularly well
suited for use in exhaust gas turbochargers.
[0015] In a furthering embodiment, the guide blade carrier ring
or/and the guide blades or/and the blade bearing pins can be
produced of a metal having a lower thermal conductivity than the
thermal conductivity of the ceramic material. In this way, the
cover disc of the ceramic material with high thermal conductivity
according to the invention can be combined with the further
components of the guide blade arrangement such as for example the
guide blade carrier ring, the guide blades and the blade bearing
pin, which are usually produced from a metal.
[0016] In a particularly preferred embodiment, the metal can have a
maximum thermal conductivity of 20 W/mK. Combined with a cover disc
of the ceramic material with high thermal conductivity, which
usually has at least 120 W/mK, heat can be particularly effectively
discharged out of the guide blade arrangement and the turbine
housing of an exhaust gas turbocharger using this guide blade
arrangement.
[0017] In a particularly preferred embodiment, the metal can be a
steel.
[0018] In order to ensure a particularly effective heat transport
through the cover disc of the guide blade arrangement, this can be
completely produced from the ceramic material in a further
embodiment.
[0019] In an embodiment that is alternative or furthering thereto,
the cover disc however can also comprise a cover disc of the
ceramic material. This means that the actual cover disc need not be
formed of the ceramic material with high thermal conductivity
according to the invention. This makes possible a particularly
cost-effective production of the cover disc, which for example can
be produced of a metal, in particular steel, so that the material
system of the cover disc and that of the remaining components of
the guide blade arrangement (guide blade carrier ring etc.) can be
identical. An advantage of such a design of the cover disc consists
in that all substantial components of the guide blade arrangement
are then constructed from the same material system and thus also
have a substantially identical thermal expansion coefficient.
[0020] In order to ensure a mechanically stable construction of the
guide blade arrangement, in particular when used in a turbine
housing of an exhaust gas turbocharger, the guide blade arrangement
in a particularly preferred embodiment can comprise at least one
spacer element, which is arranged coaxially to the blade bearing
pin, holding the guide blade carrier ring spaced from the cover
disc.
[0021] The invention also relates to an exhaust gas turbocharger,
in particular for a motor vehicle, having a guide blade arrangement
with one or a plurality of the features explained above and having
a turbine housing with a housing wall facing the guide blade
arrangement, on which the cover disc of the guide blade arrangement
is arranged. The exhaust gas turbocharger furthermore comprises a
bearing housing and a spring element supporting itself on the
bearing housing, by means of which in the axial direction via the
guide blade carrier ring a pressure force is exerted onto the at
least one spacer element, so that the latter pushes the cover disc
against the turbine housing for the axial fixing.
[0022] The invention furthermore relates to a motor vehicle having
an internal combustion engine and to an exhaust gas turbocharger
with the features explained above which is operationally connected
to this internal combustion engine for increasing its the
power.
[0023] Further important features and advantages of the invention
are obtained from the subclaims, from the drawing and from the
associated FIGURE description by means of the drawing.
[0024] It is to be understood that the features mentioned above and
still to be explained in the following cannot only be used in the
respective combination stated but also in other combinations or by
themselves without leaving the scope of the present invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0025] A preferred exemplary embodiment of the invention is shown
in the drawing and is explained in more detail in the following
description.
DETAILED DESCRIPTION
[0026] In the representation of FIG. 1, a guide blade arrangement
according to the invention is shown and designated 1. The guide
blade arrangement 1 comprises side blades 3 which are rotatably
mounted on a guide blade carrier ring 2 via a respective blade
bearing pin, wherein in the part view of FIG. 1 exemplarily only
one single such guide blade 3 and correspondingly also only one
single associated blade bearing pin is shown. The guide blade
arrangement 1 furthermore comprises a cover disc 4 which is
arranged spaced from the guide blade carrier ring 2, wherein the
guide blades 3 in each case are arranged between the cover disc 4
and the guide blade carrier ring 2. The cover disc 4 comprises a
ceramic material, which in turn has a high thermal conductivity.
The thermal conductivity of the ceramic material can have a thermal
conductivity of at least 120 W/mK, so that waste heat occurring the
blade arrangement, for example when the guide blade arrangement 1
is employed in an exhaust gas turbocharger, can be discharged to
the outside in an effective manner. The ceramic material can be
silicon nitride or silicon carbide. Silicon carbide is a chemical
ceramic compound of silicon and carbon belonging to the group of
the carbides. Since silicon carbide additionally has a high
mechanical hardness and on the other hand a very high thermal
conductivity (pure silicon carbide: approx. 350 W/mK, technical
silicon carbide: up to 140 W/mK), it is particularly well suited as
ceramic material for the cover disc of the guide blade arrangement
according to the invention. Similar is true of silicon nitride,
which in addition to its high strength is also characterized by a
very low thermal expansion coefficient and a low modulus of
elasticity. Ceramics of silicon nitride can be employed at
temperatures of up to approximately 1,300.degree. C. and are
therefore particularly well suited for use in exhaust gas
turbochargers. In principle, however, other ceramic materials with
high thermal conductivity are also possible.
[0027] The guide blade carrier ring 2 can be produced from a metal
or another suitable material, which has a lower thermal
conductivity than the thermal conductivity of the ceramic material.
Similar applies to the guide blades or/and the blade bearing pins.
For example, these components of the guide blade arrangement can be
produced from a metal (e.g. steel), which has a maximum thermal
conductivity of 20 W/mK.
[0028] In a first variant, the cover disc 4 can be designed
entirely of the ceramic material with high thermal conductivity,
which makes possible a particularly effective discharge of heat via
the cover disc 4. Alternatively to this, the cover disc 4 however
can also be formed of another material system with lower thermal
conductivity than the ceramic material with high thermal
conductivity and comprise a covering layer of the ceramic material
with high thermal conductivity. This makes possible a particularly
cost-effective production of the guide blade arrangement 1.
[0029] For example, the cover disc 4 in this case can be produced
from the same material, for example metal or steel, as the further
components of the guide blade arrangement 1, such as for example
the guide blade carrier ring 2 or the guide blades 3. In this case,
all components will then have substantially identical physical
properties. In particular, the thermal expansion coefficient of
cover disc and the remaining components is the same in this
case.
[0030] The guide blade arrangement can comprise at least one spacer
element 5, which is arranged coaxially to the blade bearing pin and
which holds the guide blade carrier ring 2 spaced from the cover
disc 4. The guide blade arrangement 1 can be part of an exhaust gas
turbocharger. Such an exhaust gas turbocharger can comprise a
turbine housing 6, which in FIG. 1 is only partially shown. The
turbine housing 6 can comprise a housing wall 7 facing the guide
blade arrangement 1, on which the cover disc 4 of the guide blade
arrangement 1 is arranged.
[0031] The exhaust gas turbocharger can furthermore comprise a
bearing housing 8 which is likewise only partially shown. On the
bearing housing 8, a spring element 9 can support itself, by means
of which in the axial direction A via the guide blade carrier ring
2 a pressure force (see arrow D) can be exerted on the at least one
spacer element 5, so that the latter pushes the cover disc 4
against the turbine housing 6 for the axial fixing.
[0032] The exhaust gas turbocharger can be employed together with
an internal combustion engine in a motor vehicle, wherein the
exhaust gas turbocharger can be operationally connected to the
internal combustion engine to increase its power.
* * * * *