WO2010054884A2

WO2010054884A2 - Shaft unit comprising a sealing device

Info

Publication number: WO2010054884A2
Application number: PCT/EP2009/062363
Authority: WO
Inventors: Ralf Böning; Holger Fäth; Ralph-Maurice KÖMPEL
Original assignee: Continental Automotive Gmbh
Priority date: 2008-11-13
Filing date: 2009-09-24
Publication date: 2010-05-20
Also published as: WO2010054884A3; DE102008057207A1

Abstract

The invention relates to a shaft unit (16) for a turbocharger, said shaft unit (16) having a shaft (18) that is situated in a bearing bush unit (20). The bearing bush unit (20) has a recess (26) at one or both ends (22, 24) for a sealing device (28) that extends in a radial direction, lying against and sealing a respective sealing surface (30).

Description

description

Shaft device with a sealing device

The invention relates to a shaft device with a sealing device, in particular an adjusting shaft device, for example for actuating or adjusting a wastegate device or a variable turbine geometry device (VTG) of a turbocharger.

A turbocharger usually has a turbine and a compressor arranged on a common shaft. The turbine is driven by the exhaust gas mass flow of a connected internal combustion engine. As a result, the turbine drives the compressor again via the common shaft. The compressor can thereby compress fresh air and supply the compressed air to the internal combustion engine.

In turbochargers with a variable turbine geometry, vanes are movably arranged, which are displaceable via an adjustment device, e.g. an adjusting ring, can be adjusted or moved to suitably change the Turbinenguerschnitt. Furthermore, there are also turbochargers with a so-called wastegate device. Here, e.g. one

Part of the exhaust gas mass flow are discharged via a bypass line, wherein the bypass line or the wastegate device is actuated via a flap. In both cases, an adjusting shaft arrangement or device is used to actuate the variable turbine geometry or the flap of the wastegate device.

For the adjustment of a mechanism within a turbocharger, such as a previously described variable turbine geometry Einrichtuddng VTG or a wastegate flap of a wastegate device, an externally actuated shaft or wave device is needed. Since the pressure inside the bearing housing is higher than in the environment, passes through the Bearing point or between the shaft and the bearing bush Rohabgas in the environment.

From the prior art, as disclosed in DE 20 2005 008 606 Ul, a Verstellwellenanordnung for a variable turbine geometry (VTG) and a wastegate device of a turbocharger is known. The adjusting shaft arrangement in this case has a stepped shaft which is connected via a fixing section with a lever of an adjusting device of a variable turbine geometry of a turbocharger. The stepped shaft has two sections of different diameters. The smaller diameter portion is provided with a circumferential groove, with a gasket or piston ring seal disposed in the groove. Furthermore, a corresponding bushing is pushed over the shaft, which is also graduated according to the shaft.

US Pat. No. 6,599,087 likewise discloses an adjusting shaft arrangement. This has in this case a shaft which is connected at its one end with an actuating lever with an actuating pin, for actuating an adjusting ring of a variable turbine geometry (VTG). The shaft is first passed through an opening in a housing wall, before it is connected to the actuating lever. The opening of the housing wall is stepped. The two stages of the opening have two different diameters, with the first stage with the smaller diameter facing outwards and the second stage with the larger diameter facing inwards. In the second stage, a sealing ring made of metal is now provided. The sealing ring has on one side a contact surface, with which it can be pressed sealingly against the wall of the first stage, when the pressure in the housing increases accordingly. As a result, the shaft is sealed to counteract leakage of exhaust gas from the housing. The object of the present invention is now to provide an improved sealing device for a shaft or shaft arrangement of a turbocharger.

This object is achieved by a shaft device having the features of patent claim 1.

Accordingly, according to the invention, a shaft device for a turbocharger is provided, wherein the shaft device has a shaft which is arranged in a bearing bush device, wherein the bearing bush device has a receptacle for at least one sealing device at one or both ends, wherein the sealing device is designed such that it presses in a sealing manner in the radial direction against a corresponding sealing surface or abuts sealingly against it.

The shaft device with the sealing device has the advantage that a very good tightness is achieved without an impact gap as in a piston ring and without a sealing gap as in a sliding sealing ring. Another advantage is that the axial displaceability is maintained.

Advantageous embodiments and modifications of the invention will become apparent from the dependent claims and the description with reference to the drawings.

In one embodiment of the invention, the sealing device has at least one or more flexible sealing elements. The flexible sealing element is, for example, a flexible ring element or sealing ring element, which can abut radially sealingly on an associated sealing surface or sealing surfaces. This has the advantage that no sealing gap results as in a displaceable sealing ring. Of Furthermore, the sealing element can adapt accordingly, for example in the case of a tilting of the shaft.

In a further embodiment according to the invention, the flexible ring element is made of metal, for example, or has this at least on. In this case, the ring element can be additionally coated, for example, in the region of its outer circumference, inner circumference, its front side and / or rear side, for example with a sealing material, such as e.g. Rubber, hard rubber, ceramic fibers, etc. The flexibility of a sealing element or ring element made of metal is achieved in that the wall thickness is correspondingly low, so that the sealing element is bendable and further by an open mold.

According to a further embodiment of the invention, the flexible ring element is for example of a graphite sealing cord or graphite sealing cords or has these. Furthermore, the flexible ring element may also consist of or comprise ceramic fibers, for example.

In principle, however, it is also possible to use any other material or combination of materials, which is flexible or flexible, which is suitably temperature-resistant or heat-resistant and has a sealing effect.

In another embodiment of the invention, the ring element is, for example accordion-shaped or wavy, so that it can be compressed, for example. In a further embodiment of the invention, the ring element may be formed curved outwards and / or inwards. Furthermore, the ring element may, for example, have a compact or solid cross-section, e.g. a round, oval and / or square cross-section.

According to a further embodiment of the invention, the ring element on its outer circumference and / or inner circumference have or form a flat support or linear support or form a flat support on one circumference and a line-shaped support on the other circumference. The ring element lies with the flat or linear support sealingly against the associated sealing surface. In addition, the sealing element or ring element can also rest with the rear side on the bearing device or in the receptacle, for example in a sealing manner. As a result, an additional sealing point can be provided. However, the sealing element or ring element can also be spaced with its rear side from the bottom of the receptacle.

In a further embodiment, optionally, for example, two sealing elements or ring elements can be provided in a receptacle, wherein the additional sealing element can form an additional safeguard for the sealing of the shaft.

According to another embodiment, a turbocharger with a shaft device is provided, in which the shaft of the shaft device acts as an adjusting shaft, which can be coupled, for example, with a turbine geometry device or with its adjusting ring for adjusting the blades of the VTG. Furthermore, the shaft or adjusting shaft can also be designed to be coupled to a wastegate device for adjusting or actuating a wastegate flap. The shaft device according to the invention has the advantage that, with a relatively small structure, the shaft device or adjusting shaft device can be sealed very well and leakage of exhaust gas from the turbocharger can be prevented.

The invention will be explained in more detail with reference to the Ausführungsbeispie- Ie given in the schematic figures of the drawings. Show it:

Fig. 1 is a sectional view through a turbocharger housing with a shaft and a sealing device according to a first embodiment of the invention; and

Fig. 2 is a sectional view through a turbocharger housing with a shaft and a sealing device according to a second embodiment of the invention.

In the figures, components are provided with the same reference numbers, which relate to the same or similar component, unless otherwise specified.

In Fig. 1, a part of a housing 10 of a turbocharger is shown. The housing 10 is in this case, for example, a bearing housing 12 with an opening 14 in the housing wall, through which a shaft device is guided. The invention is not limited to a bearing housing 12, but can in principle be applied to any housing in which a shaft is passed and a seal of the shaft or of the housing is to be provided to the outside.

The shaft device 16 is formed in the examples shown in FIGS. 1 and 2 as part of an adjusting device of a wastegate device (not shown) or a variable turbine geometry device (not shown) of the turbocharger. In this case, for example, a flap of a connected or coupled wastegate device can be actuated or opened and closed via the shaft device 16, or the blades of a connected or coupled variable turbine geometry device can be appropriately adjusted.

Such embodiments for a variable turbine geometry device VTG and a wastegate device are well known in the prior art and are therefore not described in detail. The same applies to the operation of these facilities. Examples of this are, for example, in the previously mentioned documents DE 20 2005 008 606 Ul and US Pat. No. 6,599,087. The invention is not limited to this example of the variable turbine geometry device and the wastegate device, as well as their operation. The invention can in principle be applied to any such device in which a shaft or shaft device is used.

The shaft device 16, as shown in Fig. 1, has a shaft 18 which is guided in a bearing bushing means 20. The shaft device 16 is arranged in a wall, for example, a bearing housing 12 of a turbocharger. In this case, the bearing bushing device 20 is disposed in an opening 14 of the housing wall to guide the shaft 18 through the wall.

In this case, the bearing bushing device 20 has at one or both ends 22, 24 a receptacle 26 for a sealing element 28 which bears sealingly against the respective sealing surface 30 in the radial direction so as to form or provide a sealing device 32. The respective receptacle 26 can in this case, as shown in Fig. 1, e.g. in the form of a depression at the end 22, 24 of the bearing bush means 20 may be formed.

As a sealing element 28 may be on one side, e.g. 1, at least one flexible ring element 28 is provided, which seals or presses radially against the respective sealing surface 30. More specifically, when installed, seal member 28 radially seals against shaft 18 and bushing assembly 20 of shaft assembly 16. Optionally, it may additionally rest against the bottom 36 of the receptacle 26, for example with its rear side 34, for example, in a sealing manner (not shown).

The ring element 28 is in this case made of metal or has this. The ring member 28 may for example Metal exist and eg on the front 38 and / or back 34, or only in the region of its inner circumference and / or outer circumference, optionally additionally coated, for example with at least one rubber layer (eg hard rubber, etc.) or other material, preferably for sealing is suitable and has a sufficient temperature resistance or eg in a bearing housing 12 has sufficient heat and heat resistance.

The ring element 28 e.g. made of metal, as shown in Fig. 1, is sufficiently flexible, so that it can press against the sealing surface 30 in the radial direction sealing or against the bearing bushing device 20 and the shaft 18 of the shaft device 16. The flexibility in a Ring element 28 made of metal can be provided by the fact that the metal has a sufficiently small wall thickness, so that it is not rigid but flexible or bendable and can press against the sealing surfaces sealingly. Furthermore, the ring element 28 has an open shape. The ring element 28 may be zigzag-shaped or corrugated, for example, as shown in Fig. 1, wherein it can be clamped between the shaft 18 and the receptacle 26 of the bearing bush means 20 and can be sealingly against the sealing surfaces 30.

As is further shown in FIG. 1 in the first embodiment according to the invention, the bearing bush device 20 also has a receptacle 26 at the other end 24, for example in the form of a depression in which a sealing element 28 is provided. The sealing element 28 also applies in the radial direction to the respective sealing surface 30 sealingly, so as to form a sealing device 32 or provide.

Instead of a ring element 28 made of metal, which seals against the respective sealing surface 30 in the radial direction, it is also possible to provide a ring element 28 made of a different material which has the same effect. So the material Here, for example, have or consist of graphite cords and / or ceramic fibers. The material is in this case according to temperature resistant or heat resistant, for example, in a bearing housing 12 or turbine housing or compressor housing. As shown in Fig. 1, this is

Ring element 28 made of a flexible sealing cord, such as a graphite sealing cord, which can be pressed radially in the receptacle 26. In this case, the ring member 28 is in the radial direction sealingly against the inside of the receptacle 26 of the bearing bush means 20 and sealingly on the outside of the shaft 18. Alternatively, the ring member 28, as shown in Fig. 1, while also with its back 34 on the ground the recording 26 abut, for example, sealingly.

Furthermore, the receptacle 26 can optionally also be provided with a stop or a limit 26, as indicated in FIG. 1 by a dashed line, which can counteract unwanted slipping out of the sealing element 28. The boundary 26 may be formed integrally with the bearing bush means 20 or be attached as a separate part of this.

In a second embodiment according to the invention, a sealing device 32 is provided on only one side of the shaft device 16. In this case, for example, the inner end 22 of the bearing bush means 20 is provided with a receptacle 26 in which at least one sealing element 28 is received. The sealing element 28 here is, for example, a ring element 28 made of metal or hard rubber, which is sufficiently resistant to temperature. The ring element 28 is, as shown in FIG. 2, for example arched outwards and lies in the radial direction with its outer circumference, for example flat, sealingly against the inner side of the bearing bushing device 20 and with its inner circumference, sealingly against the shaft 18 , However, the ring member 28 may also be curved inwardly (not shown). Furthermore, the sealing device 32 instead also be provided on the inside of the housing wall according to the outside of the housing wall or on both sides, as shown in Fig. 1.

In the invention, as described above by way of example with reference to FIGS. 1 and 2, the extensibility or flexibility of the sealing elements or ring elements 28 is utilized to achieve a perfect contact of sealing surfaces, without affecting additional parts, such as springs etc., to resort to.

In contrast, in the prior art described above, the sealing solution once consists of a piston ring solution in which the piston ring is located in a groove on the adjusting shaft. The other sealing solution consists of a displaceable, tightly-tolerated sealing ring, which is applied by the pressure axially to a bushing surface and thus seals.

Due to the flexibility of the ring elements according to the invention, the sealing ring elements can invest radially on a sealing surface. In this case, as described above, a very good tightness is achieved without an impact gap as in a piston ring and without a sealing gap as in a displaceable sealing ring. Another advantage of the invention lies in the adaptation of the seal when tilting the shaft. Furthermore, the axial displaceability remains.

The invention has the advantage that the shaft device can be suitably sealed, for example, with respect to an interior of a bearing housing, in order to counteract or substantially prevent leakage of exhaust gas from the bearing housing interior.

According to the invention, the sealing of the shaft means takes place in the radial direction by one, two or more flexible ring elements as sealing elements. Although the present invention has been described above with reference to the preferred embodiments, it is not limited thereto, but modified in many ways. The embodiments described above can be combined with each other, in particular individual features thereof.

Thus, for example, in the case of a bearing bush with one or two receptacles, in one or both receptacles, at least one, two or more sealing elements, i. be provided flexible ring element. In FIGS. 1 and 2, a ring element is arranged in each receptacle. In principle, however, it is also possible instead of arranging a ring element in at least one receptacle two, three or more ring elements. The ring elements may in this case be made of the same or a different material or material combination. Furthermore, the ring elements may have the same shape or a different shape or dimensioning.

Furthermore, a flexible ring element according to the invention can have, for example on its outer circumference and / or inner circumference, a flat or line-shaped bearing surface or contact surface for surface or linear sealing abutment on the outside of the bearing bushing device or on the inside of the bearing bushing

Wave of the wave device. In addition, a ring member may optionally also be provided with, for example, a sidewall, such as a skirt. is shown in Fig. 1, abut the bottom of the receptacle of the bearing bush means. Furthermore, alternatively, a stop or a limitation may be provided on a receptacle, which may counteract an unwanted slipping out of the ring member.

Furthermore, the ring element can have any desired shape or cross-section, provided that the ring element is suitably flexible and can bear a radial sealing against the inside of the bearing bushing device and against the outside of the shaft of the shaft device. The in Figs. 1 and 2 are merely exemplary and the invention is not limited to these specific embodiments.

Claims

claims

Shaft means (16) of a turbocharger, wherein the shaft means (16) comprises a shaft (18) which is arranged in a bearing bush means (20), wherein the bearing bush means (20) at one or both ends (22, 24) a receptacle (26) for a sealing device (28), which in the radial direction at a respective sealing surface (30) sealingly applies.

2. shaft device according to claim 1, characterized in that the sealing device comprises at least one flexible sealing element (28), wherein the flexible sealing element (28), for example, a flexible ring element (28) or sealing ring element (28).

3. shaft device according to claim 2, characterized in that the flexible ring member (28) consists for example of metal or this, wherein the ring member (28) is optionally additionally coated in at least one or more areas with a sealing material, such as rubber or hard rubber ,

4. shaft device according to at least one of claims 2 to 3, characterized in that the flexible ring element (28) consists for example of a graphite sealing cord or Graphitdichtschnüren or this has.

5. shaft device according to at least one of claims 2 to 4, characterized in that the flexible ring element (28) consists for example of ceramic fibers or has these.

6. shaft device according to at least one of claims 2 to 5, characterized in that the ring element

(28), for example, accordion-shaped or wavy.

7. shaft device according to at least one of claims 2 to 6, characterized in that the ring element (28) is formed outwardly and / or curved inwards.

8. shaft device according to at least one of claims 2 to 7, characterized in that the ring element (28) has a round, oval and / or angular cross-section.

9. shaft device according to at least one of claims 2 to 8, characterized in that the annular element (28) forms with its outer circumference and / or inner circumference a flat or linear support, which is sealingly pressed against the associated sealing surface (30) or can be applied.

10.Welleneinrichtung according to at least one of claims 1 to 9, characterized in that one or both receptacles (26) of the bearing bush means (20) have a delimiting element (40) which an unwanted slipping out of a sealing element (28) or ring element (28 ) counteracts.

11.Welleneinrichtung according to at least one of claims 1 to 10, characterized in that the sealing element (28) or ring element (28) in addition to one side (34) in the axial direction of the bearing bush means (20) or at the bottom of the receptacle (26 ) of the bushing device

(20) rests, for example, sealingly abuts, or is spaced therefrom.

12.Welleneinrichtung according to at least one of claims 1 to 11, characterized in that a plurality of sealing elements (28) or ring elements (28) in a receptacle (26) are providable bar, wherein the sealing elements (28) or ring elements (28) to each other abutment, for example, sealingly abutment, or are spaced from each other.

13. A turbocharger with a shaft device (16) according to any one of claims 1 to 12.

14. Turbocharger according to claim 13, characterized in that the shaft (18) of the shaft device (16) is an adjusting shaft for adjusting blades of a variable turbine geometry device, wherein the adjusting shaft can be coupled for example with an adjusting ring of the variable turbine geometry device.

15. Turbocharger according to at least one of claims 13 to 14, characterized in that the shaft (18) of the shaft means (16) is an adjusting shaft for adjusting a flap of a wastegate device.

16. A turbocharger according to at least one of claims 13 to 15, characterized in that the shaft means (16) in an opening (14) of a wall of a bearing housing (12), turbine housing and / or compressor housing is providable.