VARIABLE TURBINE AND/OR COMPRESSOR GEOMETRY FOR AN EXHAUST GAS TURBOCHARGER

Abstract

At least one of a variable turbine geometry and a variable compressor geometry for an exhaust gas turbocharger may include a housing including a first housing wall and a blade bearing ring having at least one guide blade rotatably mounted thereon. A control lever may be included for adjusting the at least one guide blade between a closing position and an opening position. An actuating shaft may be connected to the control lever in a rotationally fixed manner along a rotation axis. The actuating shaft may be rotatably mounted on the housing via a passage opening disposed in the first housing wall. The actuating shaft may directly support itself on the first housing wall in the passage opening.

Claims

1. At least one of a variable turbine geometry and a variable compressor geometry for an exhaust gas turbocharger, comprising: a housing including a first housing wall, a blade bearing ring including at least one guide blade rotatably mounted thereon, a control lever for adjusting the at least one guide blade between a closing position and an opening position, an actuating shaft connected to the control lever in a rotationally fixed manner along a rotation axis, the actuating shaft rotatably mounted on the housing via a passage opening disposed in the first housing wall, and wherein the actuating shaft directly supports itself on the first housing wall in the passage opening.

2. The at least one of the variable turbine geometry and the variable compressor geometry according to claim 1, further comprising a protective coating disposed on a wall section of the first housing wall delimiting the passage opening.

3. The at least one of the variable turbine geometry and the variable compressor geometry according to claim 2, wherein the protective coating contains at least one of carbon and nitrogen.

4. The at least one of the variable turbine geometry and the variable compressor geometry according to claim 1, wherein: the housing further includes a second housing wall disposed opposite the first housing wall, the second housing wall together with the first housing wall at least partly delimiting a housing interior, wherein the second housing wall includes a recess disposed axially aligned with the passage opening in the first housing wall with respect to the rotation axis, and the actuating shaft includes an axial end section arranged in the recess directly supported on the second housing wall of the housing.

5. The at least one of the variable turbine geometry and the variable compressor geometry according to claim 1, wherein the housing further includes a second housing wall having an inner surface facing towards a housing interior, the inner surface of the second housing wall include a protective coating disposed in a region of a recess mounting the actuating shaft opposite of the passage opening.

6. The at least one of the variable turbine geometry and the variable compressor geometry according to claim 4, wherein the recess is configured as an axial stop for stopping the actuating shaft in a movement along a centre longitudinal axis of the actuating shaft in a direction towards the second housing wall of the housing.

7. The at least one of the variable turbine geometry and the variable compressor geometry according to claim 1, wherein the control lever is fixed to the actuating shaft via at least one of a clamping connection, a screw connection and a press connection.

8. The at least one of the variable turbine geometry and the variable compressor geometry according to claim 1, wherein the housing further includes a second housing wall which together with the first housing wall at least partially defines a housing interior, and further including a spring-elastic element arranged between the second housing wall at one end and the control lever at another end for preloading the control lever towards the first housing wall.

9. The at least one of the variable turbine geometry and the variable compressor geometry according to claim 8, wherein the spring-elastic element includes a coil spring, arranged coaxially to a centre longitudinal axis of the actuating shaft and spirally wraps the actuating shaft radially on an outside of the actuating shaft.

10. The at least one of the variable turbine geometry and the variable compressor geometry according to claim 1, further comprising a bearing disc arranged between control lever and a second housing wall of the housing disposed opposite the first housing wall, the bearing disc configured to seal a housing interior defined at least partly by the first housing wall and the second housing wall against a surrounding environment of the housing.

11. The at least one of the variable turbine geometry and the variable compressor geometry according to claim 4, wherein: the recess of the second housing wall further includes a passage opening, the passage opening of the recess including a first opening diameter in a first axial section facing the housing interior, wherein the first axial section extends into a second axial section of the passage opening of the recess in a direction away from the housing interior, the second axial section including a second opening diameter that is smaller than the first opening diameter, the actuating shaft is received in the first axial section, and a preload element disposed in the second axial section for preloading the actuating shaft against the first housing wall, wherein the preload element is arranged between a face end of the actuating shaft facing the second housing wall and a housing wall of at least one of a compressor housing and a turbine housing, the at least one of the compressor housing and the turbine housing mountable against a side of the second housing wall facing away from the housing interior.

12. The at least one of the variable turbine geometry and the variable compressor geometry according to claim 11, wherein the preload element is configured as a stamp element and includes a stamp shaft arranged in the second axial section of the passage opening of the recess, the stamp shaft connected to a stamp section disposed away from the actuating shaft with respect to the stamp shaft, wherein the stamp section is received in a second recess arranged complementary to the stamp section, the second recess disposed on the side of the second housing wall facing away from the housing interior and defining at least part of the passage opening of the recess.

13. An exhaust gas turbocharger, comprising: at least one of a variable turbine geometry and a variable compressor geometry, the at least one of the variable turbine geometry and the variable compressor geometry including: a housing including a first housing wall and a second housing wall, the first housing wall together with the second housing wall at least partially defining a housing interior; a blade bearing ring including at least one guide blade rotatably mounted thereon; a control lever for adjusting the at least one guide blade between a closing position and an opening position; and an actuating shaft connected rotationally fixed to the control lever and being rotatable along a rotation axis, wherein the actuating shaft is rotatably mounted on the housing via a passage opening disposed in the first housing wall and a recess disposed in the second housing wall, the second housing wall disposed opposite the first housing wall with respect to the rotation axis, wherein the actuating shaft is directly mounted on the first housing wall in the passage opening.

14. The exhaust gas turbocharger according to claim 13, further comprising a protective coating disposed on a wall section of the first housing wall bordering the passage opening.

15. The exhaust gas turbocharger according to claim 13, wherein the recess is arranged axially aligned with the passage opening, and wherein the actuating shaft includes an axial end section arranged in the recess directly supported on the second housing wall.

16. The exhaust gas turbocharger according to claim 13, wherein the recess defines an axial stop for stopping the actuating shaft in an axial movement along a centre longitudinal axis of the actuating shaft in a direction towards the second housing wall.

17. The exhaust gas turbocharger according to claim 13, wherein the control lever is fixed to the shaft via at least one of a clamping connection, a screw connection and a press connection.

18. The exhaust gas turbocharger according to claim 13, further comprising a spring-elastic element arranged between the second housing wall and the control lever, the spring-elastic element configured to preload the control lever towards the first housing wall.

19. The exhaust gas turbocharger according to claim 18, wherein the spring-elastic element includes a coil spring arranged coaxially to a centre longitudinal axis of the actuating shaft.

20. The exhaust gas turbocharger according to claim 13, wherein the second housing wall on an inner surface facing towards the housing interior includes a protective coating disposed in a region of the recess.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0024] It shows, in each case schematically,

[0025] FIG. 1 an example of a variable turbine and/or compressor geometry according to the invention in a longitudinal section,

[0026] FIG. 2 a first variant of the example of FIG. 1,

[0027] FIG. 3 a second variant of the example of FIG. 1,

[0028] FIG. 4 a detail representation of the control lever of the FIGS. 1 to 3, which is fastened to the actuating shaft by means of a screw connection,

[0029] FIG. 5 a further detail representation of the control lever of the FIGS. 1 to 3, which is fastened to the actuating shaft by means of a clamping connection.

DETAILED DESCRIPTION

[0030] FIG. 1 shows in a longitudinal section an example of a variable turbine and/or compressor geometry 1 according to the invention. The same comprises a housing 2 delimiting a housing interior 3, which housing 2 comprises a first housing wall 7a and a second housing wall 7b located opposite the first housing 7a. The variable turbine and/or compressor geometry 1 also comprises a blade bearing ring, on which a plurality of guide blades is rotatably mounted (not shown). For adjusting the guide blades between their opening and closing position, the variable turbine and/or compressor geometry comprises an actuating device in the form of an actuating lever 37, which is coupled to the rotatable guide blades for their adjustment between the opening and closing position via an adjusting ring (not shown) that is mounted on the housing. For moving the actuating lever 37, the same is connected to an actuating shaft 5 in a rotationally fixed manner. The variable turbine and/or compressor geometry 1 furthermore comprises a control lever 4 that is connected to the actuating shaft 5 in a rotationally fixed manner, which in turn can be drive-connected to an electric actuator (not shown). The actuating shaft 5 has a centre longitudinal axis M, through the position of which an axial direction A of the actuating shaft 5 is determined. For rotationally fixing the control lever 4 on the actuating shaft 5, a suitably dimensioned break-through 16 can be provided in the control lever 4, which is engaged through by the actuating shaft 5.

[0031] Corresponding to FIG. 4, the control lever 4 can be fixed on the actuating shaft 5 in rotationally fixed manner by means of a screw connection 12. Such a screw connection 12 can comprise a threaded bore 13 provided in the actuating shaft 5, which is aligned with a passage opening 15 provided in the control lever 4. For fixing the control lever 4 on the actuating shaft 5, a threaded screw 14 is used.

[0032] FIG. 5 shows a variant that is alternative to the scenario of FIG. 4 for the rotationally fixed fastening of the control lever 4 on the actuating shaft 5 with the help of a clamping connection. In this case, the control lever 4 can be equipped with two pincer-like end sections 17a, 17b, which in each case partly form a break-through 16 for receiving the actuating shaft 5 and between which a gap-like intermediate space 18 is additionally formed. In the end section 17a, a threaded bore 19a is provided, in the end section 17b a conventional bore aligned with the threaded bore 19a, which is aligned with the threaded bore 19a. By screwing a threaded screw 20 through the bore 19b into the threaded bore 19a, the two end sections 17a, 17b are pressed against one another and in this way pressed against the actuating shaft 5 so that the desired clamping effect is achieved. With the variant of FIG. 5 for both the actuating shaft 5 and also for the break-through 16, a non-rotation symmetrical geometry such as for example the geometry of a polygon in the form of a hexagonexemplarily shown for example in FIG. 5is recommended in the cross section perpendicularly to the centre longitudinal axis M. Alternatively or additionally to the screw respectively clamping connections shown in the FIGS. 4 and 5, fastening the actuating shaft 5 on the control lever 4 by means of pressing is also conceivable, in particular in connection with the non-rotation-symmetrical geometry of actuating shaft 5 and break-through 16 mentioned above. In this case, the screws 14 and 20 can be omitted.

[0033] With conventional variable turbine and/or compressor geometries, the actuating shaft 5 is usually at least partially received in a bearing bushing attached to the blade bearing ring or on the housing 2 and rotatably mounted in the same. As illustrated in FIG. 1, the actuating shaft 5 with the variable turbine and/or compressor geometry 1 according to the invention by contrast is rotatably mounted directly on the housing 2. To this end, the actuating shaft 5 is at least partly received in a passage opening 6, which is formed in the first housing wall 7a of the housing 2. As is further evident from FIG. 1, the actuating shaft 5 supports itself within the passage opening 6 directlyi.e. without using a bearing bushing or a similar component that is connected to the housing 2 in a fixed manneron the first housing wall 7a. In the second housing wall 7b on the inside a recess 10 is provided, which is aligned with the passage opening 6 provided in the first housing wall 7a. The actuating shaft 5 is received in the recess 10 with an axial end section 11 and rotatably mounted in the same. This means that the actuating shaft 5 supports itself not only within the passage opening 6 on the first housing wall 7a, but within the recess 10 also on the second housing wall 7b. In both cases, the actuating shaft 5 supports itself directly on the two housing walls 7a, 7b. Preferably, an inner diameter d.sub.i of the passage opening 6 and of the recess 10 in each case corresponds to a shaft diameter d.sub.v of the actuating shaft 5.

[0034] On a wall section 9 of the first housing wall 7a delimiting the passage opening 6 andalternatively or additionally to thisin the region of the second housing wall 7b delimiting the recess 10, a protective coating 8 can be provided which improves the resistance of the housing 2 to abrasion and wear. The protective coating 8 can be applied onto the wall section 9 and optionally also onto further regions of the housing 2 by means of nitrocarburising and contain carbon and nitrogen. The recess 10, in particular its recess depth t, is dimensioned and designed in the example scenario in such a manner that it acts as axial stop for the actuating shaft 5 for a movement along the centre longitudinal axis towards the second housing wall 7b of the housing 2.

[0035] The FIG. 2 shows a variant of the example of FIG. 1. In order to prevent axial movement of the actuating shaft 5 within the housing 2, brought about for example through axial play of the actuating shaft 5 in the housing 2 due to tolerances, a spring-elastic element 21 is arranged in the housing interior 3, which preloads the control lever 4 and thus also the actuating shaft 5 that is fixed on the control lever 4 in a rotationally fixed manner towards the first housing wall 7a. To this end, the spring-elastic element 21 supports itself on the one end on the second housing wall 7b and on the other end on the control lever 4. As is schematically shown in FIG. 2, the spring-elastic element 21 can be or comprise a coil spring 22, which is arranged coaxially to the centre longitudinal axis M of the actuating shaft and radially wraps the actuating shaft 5 on the outside. In variants of the example, a suitable spiral spring, wave spring or disc spring can also be used instead of a coil spring.

[0036] With a further version of the example of FIG. 1 shown in FIG. 3, the recess 10 provided in the second housing wall 7b is also designed in the form of a passage opening 23. Such a passage opening 23 has a first opening diameter d.sub.1 in a first axial section 24a facing the housing interior 3, which corresponds to the inner diameter d.sub.i of the recess 10 in the example of the FIGS. 1 and 2. The first axial section 24a of the passage opening 23 moving away from the housing interior 3 merges into a second axial section 24b with a second opening diameter d.sub.2, that is smaller than the first opening d.sub.1. The actuating shaft 5 is received in the first axial section 24a. In the second axial section, a preload element 25 is arranged, which for preloading the actuating shaft 5 against the first housing wall 7a supports itself on the one end on a face end 26 of the actuating shaft 5 facing the second housing wall 7b. On the other end, the preload element 25 can support itself on a housing wall 27 of a compressor/turbine housing 29. The compressor/turbine housing 29 abuts the second housing watt 7b on a side 28 of the same facing away from the housing interior 3. In this way, a preload of the actuating shaft 5 towards the first housing wall 7a can be achieved. In addition to this, the preload element 25 following disassembly of the housing 2 from the compressor/turbine housing 29 is particularly easily accessible to a worker.

[0037] The preload element 25, as shown in FIG. 3, can be designed stamp-like and comprise a stamp shaft 30, which is arranged in the second axial section 24b of the passage opening 23. This stamp shaft 30 moving away from the actuating shaft 5 merges into a stamp section 31 which is received in a recess 32 that is complementary to the stamp section 31 and formed on the side 28 of the second housing wall 7b facing away from the housing interior and protrudes over the second housing wall 7b for as long as the compressor/turbine housing 29 is not mounted on the second housing wall 7b.

[0038] For sealing the housing interior 3 against the outer surroundings 33 of the housing 2, a bearing disc 34 acting as sealing element can be provided between control lever 4 and first housing wall 7a in the examples of the FIGS. 1 to 3, which seals an interior space between the actuating shaft 5 and the wall section of the first housing wall 7a of the housing 2 forming the passage opening 6.

[0039] The recess 10, as shown in FIG. 3, is also designed as passage opening 23 so that a receiving groove can be provided in the wall section of the second housing wall 7b delimiting the passage opening 23, in which partly a sealing element 35, for example in the manner of a sealing ring, is received. The sealing element 35 serves for sealing the housing interior 3 against the outer surroundings 33 in the region of the passage opening 33.