EP3721066A1

EP3721066A1 - Wastegate assembly for a turbocharger

Info

Publication number: EP3721066A1
Application number: EP18819016.9A
Authority: EP
Inventors: Christian RÖMER; Christian Kirschner; Markus Pflüger; Maximilian Hoffmann
Original assignee: ElringKlinger AG; Vitesco Technologies GmbH
Current assignee: ElringKlinger AG; Vitesco Technologies GmbH
Priority date: 2017-12-05
Filing date: 2018-12-04
Publication date: 2020-10-14
Also published as: CN111566327A; US20200291850A1; WO2019110581A1; DE102017128830A1

Abstract

The invention relates to a wastegate assembly for a turbocharger having a turbine casing. The wastegate assembly has a wastegate flap (5a), a wastegate flap lever (5c), a wastegate spindle (5b) and a bearing bush (7) for the wastegate spindle (5c). In addition, the wastegate assembly has a sealing unit (11, 17) formed from a soft-material volume sealing ring (11) and a diaphragm spring (17) that contacts the volume sealing ring (11).

Description

Description / Description

Wastegate arrangement for an exhaust gas turbocharger

The invention relates to a Wastegateanordnung for a gas turbocharger from.

An exhaust gas turbocharger usually has a turbine housing, a compressor housing and a bearing housing arranged between the turbine housing and the compressor housing. In the turbine housing mounted on a shaft turbine wheel is provided, which is driven by the exhaust gas flow of a Brennkraftma machine. The rotational movement of the shaft is carried on a likewise mounted on the shaft compressor wheel, which is arranged in the compressor housing. The Wel le is rotatably mounted in the bearing housing.

In order to be able to operate such an exhaust gas turbocharger both at high engine speeds and at low engine speeds meaningful, it requires a regulation of the binengehäuse in the turbine flowing exhaust gas mass flow.

It is known to perform such a control of the housing flowing into the turbine exhaust gas mass flow using a Wastegateanordnung. This wastegate arrangement has inter alia a wastegate flap closing a wastegate channel, a wastegate spindle and a wastegate flap lever. The wastegate flap lever is part of a Linkagesystems, which further includes a rule Stan ge and an actuator. This Linkagesystem allowed ei ne adjustment of the wastegate flap such that it is closed in front of small exhaust gas mass flows and is open in the presence of large exhaust gas mass flows. Consequently, in the presence of small exhaust gas mass flows of the entire exhaust gas mass flow is supplied to the turbine wheel and drives it. In the presence of large exhaust gas mass flows is part of the Exhaust gas mass flow past the turbine wheel passes through the wastegate channel and thus bypasses the turbine wheel.

From DE 10 2009 030 520 Al a control flap assembly of an exhaust gas turbocharger is known. This control flap assembly comprises a flap plate, a binengehäuse by means of a bushing in the door guided flap shaft and a sealing device for sealing the flap shaft to at least one Dichtstel le. The flap shaft is connected via an outer flap lever with a control rod of a drive and an inner flap lever with the flap plate. The Dichtein direction has at least one resilient sealing lip which presses under bias on the sealing point.

From DE 20 2011 109 832 Ul an actuator for an exhaust gas flow control of an exhaust gas turbocharger be known, which may be a Wastegateanordnung. This Wastegateanordnung has a ge in a bushing led wastegate spindle, which is connected to a Spindelstellele element. In the transition region between the Wastega tespindel and the spindle adjusting element a metal ring is provided as a seal, which has resilient properties. This sheet metal ring is plate-shaped and has a central opening, an inner ring portion and an outer Ringbe rich, wherein the inner ring portion rich with the outer ring is connected by a central ring portion. The inner and outer ring portion are flat and lie in the mirror axis perpendicular, in the axial direction staggered planes, while the middle Ringbe rich in section along the axis obliquely to the other two annular areas.

The Wastegatespindel a Wastegateanordnung is - as stated before standing - usually in a bearing bush gela siege, which is pressed into the turbine housing. Since during operation of the exhaust gas turbocharger the wastegate spindle heats up faster than the bearing bushing, the wastegate spindle can get stuck inside the bearing bush. To this To avoid jamming, the thermal expansion of the wastegate spindle can be compensated by a larger diameter of the bearing bush compared to the diameter of the wastegate spindle. Due to the resulting gap dimension can escape during operation of the exhaust gas turbocharger part of the exhaust gas mass flow undesirably from the turbine housing through a leak between the bearing bush and the wastegate spindle in the environment of the exhaust gas turbocharger.

WO 2013/0173 055 A1 discloses a shaft sealing system for a turbocharger. In this WellenabdichtSystem a spring-loaded, self-centering, complementary pair of opposing sealing surfaces is used to seal a leakage gap between the shaft and a bearing bush. These sealing surfaces are compressed by the force of the spring to achieve the desired seal.

From DE 10 2008 057 207 Al a shaft device ei Nes turbocharger is known, wherein the shaft means comprises a shaft which is arranged in a bearing bush means, wherein the bearing bush means at one or both ends of a receptacle for a sealing device has, which is in radial direction sealingly applied to a respective sealing surface.

The object of the invention is to provide a Wastegateanord- tion, in which the escape of a portion of the exhaust gas mass flow through the leakage gap between the bearing bush and the wastegate spindle is avoided in the environment.

This object is achieved by a Wastegateanordnung with the features specified in claim 1. Advantageous developments and developments of the invention are set forth in the dependent claims. A wastegate assembly according to the invention comprises a waste gate flap, a wastegate flap lever, a wastegate pin, and a wastegate spindle bearing bushing. Furthermore, it contains a sealing unit which is formed by a Volu mendichtring made of soft material and a ring with the volume density contacted plate spring.

The bearing bush preferably has a Verbreiterungsab section, in which the volume sealing ring is inserted.

The volume sealing ring consists of soft material, preferably graphite or mica, in which one or more carrier layers, such as steel strips, are layered. The diaphragm spring is made of high temperature Materi al, for example, for temperatures above 300 ° C, preferably, temperatures above 500 ° C, resistant, preferably made of steels with a Ni content of 6.0-13.0%, a Cr content of 13-21%, a C content below 2% and a Mn content below 2%, or made of materials having a Ni content of over 50%, a Cr content of 17-22%, a Ti content of 0.5-2 , 0% and an Al content of over 0.5%. These materials are characterized by the fact that the mechanical properties and the thermal resistance are still sufficient for the spring function of the diaphragm spring at high temperatures.

Advantageously, the widening portion of the bearing bush in which the wastegate flap lever end facing the bearing bush is arranged. The diaphragm spring is between tween the volume seal made of soft material and the wastegate lever positioned. The diaphragm spring seals between the wastegate flap lever and the volume sealing ring made of soft material and replaces the wear that occurs over the service life of this sealing system.

The volume sealing ring made of soft material is in an advantageous Wei se in the widening portion of the bearing bush is pressed to achieve the desired sealing effect. This Pressing the volume sealing ring in the Verbreiterungsab section takes place in the axial direction, ie in the direction of the longitudinal axis of the wastegate spindle. By this pressing in the axial direction is due to a strong plasticization of the material of the volume seal a high force in radia ler direction exerted both on the bearing bush and on the wastegate spindle. This creates between the Wastegate spindle and the bearing bush a radial preload voltage, which is maintained during operation of the exhaust gas turbocharger and enhances the sealing effect of the volume seal made of soft material.

The invention will be explained by way of example with reference to the figures. It shows

FIG. 1 shows a perspective sketch to illustrate the structure of an exhaust gas turbocharger equipped with a wastegate arrangement,

Figure 2 is a sectional view for illustrating a

Wastegate arrangement

3 is a sectional view illustrating the leak path between the wastegate spindle and its La gerbüchse,

FIG. 4 is a sectional view illustrating a first embodiment of the invention;

Figure 5 is an enlarged view of a portion of the sectional view shown in Figure 4 and

Figure 6 is a sectional view for illustrating a

second embodiment of the invention.

FIG. 1 shows a perspective sketch for the illustration of the structure of an exhaust gas turbocharger equipped with a wastegate arrangement. This exhaust gas turbocharger has a Turbine housing 1, a compressor housing 2 and arranged between the turbine housing and the compressor housing bearing housing 3. The turbine housing 1 is connected to the exhaust manifold 1a of an internal combustion engine via which a hot exhaust gas mass flow of the internal combustion engine is supplied to the turbine wheel arranged in the turbine housing. The turbine wheel is driven by this hot exhaust gas mass flow or rotated. As a result, the shaft of the exhaust gas turbocharger, not shown, on which the door is arranged binenrad, is rotated. This rotation of the shaft of the exhaust gas turbocharger is transmitted to the housing 2 in the Verdichterge and also mounted on the shaft of Abgastur boladers attached compressor wheel. This rotation of the compressor wheel compresses fresh air supplied to the compressor. This compressed fresh air is supplied to the internal combustion engine to increase their performance. The shaft of the exhaust gas turbocharger is rotatably mounted in the bearing housing 3.

Furthermore, in the figure 1 shows a Wastegateanordnung 5 ge shows. This is arranged in the turbine housing 1 and has a wastegate flap 5a that can be actuated via a wastegate flap lever 5c and a wastegate spindle 5b and that is designed to open and close a wastegate channel. Be the operation or control of the wastegate flap using an actuator 6, which is connected via an actuating element 6a with the wastegate lever 5c.

As already stated above, the Wastegatespindel 5 b using a bearing bush in the turbine housing ge outsourced, this bearing bush is pressed, for example, in the turbine nengehäuse. This is illustrated below with reference to Figure 2, which shows a sectional view Ver Veraulaulung a Wastegateanordnung. The wastegate arrangement shown in FIG. 2 has a wastegate flap 5a, which is connected to the wastegate flap lever 5c of a linkage system 14 via a wastegate spindle 5b. Furthermore, one does not belong to this linkagesystem Wastegate handlebar shown in detail, via which the wastegate flap lever 5c is connected to an actuator also not shown in detail. The wastegate spindle 5b is connected in its lower end region in FIG. 2 to the wastegate flap 5a and in its upper end region to the wastegate lever 5c. The Wastegatespindel 5 b is guided in the bearing bush 7, which is pressed into the turbine housing 1 a.

Since - as also stated above - due to the occurring during operation of the exhaust gas turbocharger faster heating the Wastegatespindel 5b compared to La gerbüchse 7, the diameter of the bearing bush is larger compared to the diameter of the wastegate spindle, there is in most operating conditions of the exhaust gas turbocharger a leak path 9 between the Wastegatespindel 5 b and the bearing bushing. 7

This is shown in Figure 3, which has a sectional view illustrating the leak path 9 between the Wastega tespindel 5 b and the bearing bush 7 to the object. From this sectional view it can be seen that this leak path 9 extends over the entire length of the bearing bushing 7. He is in his lower end with a flow direction behind the turbine arranged exhaust chamber 10 in connec tion. Exhaust gas enters the leakage path 9 from this exhaust gas space 10, passes through it and is discharged in the upper end region of the bearing bush 7 through a gap between the bearing bush 7 and the wastegate flap lever 5c to the environment 8 in an undesired manner.

To prevent this, according to the present invention, a seal is used, which is ge of a volume sealing ring and contacted with the volume sealing ring plate spring forms. A volume sealing ring is understood to be a seal for high-temperature applications, which has a sealing ring which is encircling a ring axis in a direction of rotation and has the opposite high temperature. temperatures, for example, temperatures above 300 ° C, preferably, temperatures above 500 ° C, is formed resistant. This volume sealing ring is made of soft material, preferably graphite or mica, in which preferably one or more thin support layers, for example, fabric layers, preferably steel strips or steel foils, are incorporated, which upon insertion of the volume seal at its sealing point together with the graphite or Glim mer be pressed.

FIG. 4 is a sectional view illustrating a first embodiment of the invention. Also in this embodiment, the Wastegatespindel 5 b in egg ner pressed into the turbine housing 1 bearing bushing 7 leads GE. This bearing bushing 7 has in its in Figure 4 obe ren end portion of a Wastegatespindel 5b surrounding Ver broadening section 7a. In this Verbreiterungsab section 7a, a volume sealing ring made of soft material 11 is set, which is preferably be made of graphite or mica be, in which one or more carrier layers, for example, thin steel strips are layered. This volume sealing ring 11 is used during assembly of Wastegateanord- tion in Figure 4 from above in the axial direction in the United breiterungsabschnitt 7 a of the bearing bush 7. After this pressing a disc spring 17 is placed from above in the axial direction of the volumetric seal 11 and used to bias the volume seal 11 in the axial and ra dialer direction. It is exerted by the compression of the volume sealing ring 11 in the axial direction due to a strong plasticization of the material of the volume sealing ring 11, a high force in the radial direction 16 on both the La gerbüchse 7 and 5b on the wastegate spindle. This creates a radial bias between the bearing bushing 7 and the wastegate spindle 5b, which is maintained over the operating life of the Wastegateanordnung.

By pressing in the axial direction of the volume mendichtring 11 in the broadening portion 7a of the bearing bushing 7 and the radial bias formed between the bearing bushing 7 and the waste gate spindle 5b, the sealing effect of the volume seal 11 is increased such that in Be drove the exhaust gas turbocharger an undesirable escape of passed through the leak path 9 exhaust We are effectively prevented from reaching the environment.

FIG. 5 shows an enlarged view of a portion of the sectional view shown in FIG. In this enlarged view, the turbine housing 1, the Ver are broader portion 7a of the bearing bush 7, the Wastegatespin del 5b, the plate spring 17, the volumetric seal 11 and the wastegate lever 5c illustrated. Furthermore, in FIG. 5, the force paths 12 and the sealing surfaces 13 are illustrated, resulting in or through the insertion and compression of the volume sealing ring 11 into the extension 7a of the bearing bush. Furthermore, it can be seen from FIG. 5 that the turbine housing 1 has a receiving stage 1b for receiving the widening portion 7a of the bearing bush.

Figure 6 is a sectional view illustrating a second embodiment of the invention. This differs from the first embodiment shown in Figure 4 only in that even in the lower end of the bearing bush 7, a volume sealing ring 11 is vorgese hen. This further volume sealing ring increases the safety that no exhaust gas can be discharged from the exhaust gas chamber 10 via the leak path 9 to the environment 8. Reference sign list

1 turbine housing

la exhaust manifold

lb recording level

2 compressor housing

3 bearing housing

4 turbocharger rotor

5 wastegate arrangement 5a wastegate flap

5b Wastegate spindle

5c wastegate lever

6 actuator

6a Stelleleme

7 bearing bush

7a widening section

8 environment

9 leak path

10 exhaust gas space

11 volume seal

12 power paths

13 sealing surfaces

14 Linkage system

15 axial direction

16 radial direction

17 plate spring

Claims

1 Claims / Patent Claims

First Wastegateanordnung (5) for a turbine housing facing exhaust gas turbocharger, with

a wastegate flap (5a),

a wastegate flap lever (5c),

a wastegate spindle (5b) and

a bearing bush (7) for the wastegate spindle,

characterized in that it comprises a seal (11, 17), which is formed by a volume sealing ring (11) and a with the volume sealing ring (11) contacted plate spring (17).

2. Wastegateanordnung according to claim 1, characterized in that the bearing bush (7) has a widening portion (7 a) and that the volume sealing ring (11) in the United breiterungsabschnitt (7 a) of the bearing bush (7) is inserted.

3. Wastegateanordnung according to claim 1 or 2, characterized in that the volume sealing ring (11) is made of soft material be, in which one or more carrier layers are incorporated.

4. Wastegate arrangement according to one of the preceding Ansprü surface, characterized in that the plate spring (17) consists of a high temperature resistant material.

5. Wastegateanordnung according to any one of claims 2-4, characterized in that the widening portion (7 a) of La gerbüchse (7) in which the wastegate flap lever (5 c) facing th end portion of the bearing bush (7) is arranged and that the plate spring (17) between the volume seal (11) and the wastegate lever (5c) is positioned.

6. Wastegateanordnung according to any one of claims 2-5, characterized in that the volume sealing ring (11) in the United breiterungsabschnitt (7 a) is pressed. 2

7. Wastegate arrangement according to one of the preceding Ansprü surface, characterized in that between the Wastegatespin- del (5 b) and the bearing bush (7) has a radial bias be available.

8. Wastegateanordnung according to any one of claims 2-7, characterized in that the turbine housing (1) has a receiving stage (lb), in which the widening portion (7 a) of the bearing bush (7) is inserted.

9. Wastegateanordnung according to any one of claims 5-8, characterized in that it also in the end of the Wastegateklappenhe- (5c) facing away from the bearing bush (7) has a Vo lumendichtring (11).