turbocharger

Abstract

Turbocharger, with a turbine (1) for the expansion of a first medium, with a compressor for compressing a second medium using energy obtained in the turbine (1) during the expansion of the first medium, wherein the turbine (1) comprises a turbine casing (3) and a turbine rotor (6), wherein the compressor has a compressor housing and a compressor rotor coupled to the turbine rotor (6) via a shaft (7), wherein the turbine housing (3) and the compressor housing are each connected to a bearing housing (2) arranged between them, in which the shaft (7) is supported, wherein the turbine housing (3) has a turbine inlet housing (4) and accommodates an insert (5) and a nozzle ring (9) with guide vanes (11), characterized in that The nozzle ring (9) is connected to a first cover ring (12) of the same via first fastening means (13) to a flange (14) of the bearing housing (2), wherein several radially outward extending projections (15) are formed on the flange (14) of the bearing housing (2), to which the first cover ring (12) of the nozzle ring (9) is connected, distributed around the circumference, wherein the first fastening means (13) penetrate the projections (15) of the flange (14) of the bearing housing (2) and engage with the first cover ring (12) of the nozzle ring (9).

Description

[0001] The invention relates to a turbocharger.

[0002] A turbocharger consists of a turbine and a compressor. In the turbine, a first medium, usually exhaust gas, is expanded, thereby generating energy. In the compressor, a second medium, usually intake air, is compressed, utilizing the energy generated in the turbine during the expansion of the first medium. The turbine has a turbine housing and a turbine rotor. The compressor has a compressor housing and a compressor rotor. The turbine rotor and compressor rotor are coupled via a shaft, which is supported in a bearing housing. This bearing housing is connected to the turbine housing on one side and to the compressor housing on the other.

[0003] It is also known from practice that the turbine housing of a turbocharger has a turbine inlet housing through which the first medium to be depressurized can be fed to the turbine rotor. The turbine housing accommodates an insert and a nozzle ring. Depressurized first medium can be discharged from the turbine via the insert, which extends radially outwards adjacent to the turbine rotor blades. The nozzle ring, also referred to as a turbine guide vane or guide structure, has guide vanes that are positioned upstream of the turbine rotor in the direction of flow of the first medium, and over which the depressurized first medium is guided upstream of the turbine rotor.

[0004] For example, reference is made to similarly constructed turbochargers, DE 39 41 715 A1, DE 10 2008 017 821 A1, DE 10 2007 057 345 A1, DE 103 37 495 A1, DE 10 2008 005 658 A1 and DE 10 2004 033 884 A1.

[0005] In turbochargers known from practice, the turbine inlet housing is typically connected to the bearing housing via a clamping jaw connection, whereby the nozzle ring is also attached via the clamping jaw connection, namely by clamping a flange of the nozzle ring between flanges or mounting sections of the bearing housing and the turbine inlet housing.

[0006] In turbochargers known from practical experience, the nozzle ring and turbine inlet housing are therefore mounted together or dependently on each other on the bearing housing.

[0007] During operation, the nozzle ring is subject to thermally induced deformation. In turbochargers known from practical experience, this leads to the connection between the nozzle ring, bearing housing, and turbine inlet housing also being subject to deformation, causing wear on this connection and reducing the sealing effect in this area. This is a disadvantage. Therefore, there is a need for a more reliable way to attach the nozzle ring to the turbocharger's bearing housing.

[0008] Based on this, the present invention aims to create a novel turbocharger.

[0009] This problem is solved by a turbocharger according to claim 1. According to the invention, the nozzle ring is connected to a flange of the bearing housing via first fastening means on a first cover ring of the same, wherein several radially outward extending projections are formed on the flange of the bearing housing to which the first cover ring of the nozzle ring is connected, distributed around the circumference, and wherein the first fastening means penetrate the projections of the flange of the bearing housing and engage with the first cover ring of the nozzle ring.

[0010] The connection of the nozzle ring to the bearing housing flange via the first fastening elements, which engage the flange projections, allows for reliable attachment of the nozzle ring to the bearing housing. Stresses, especially tangential stresses, in the bearing housing flange are reduced, particularly because the flange projections can deform more quickly and thus more uniformly along with the nozzle ring due to temperature changes.

[0011] Preferably, the first fastening means extend axially from the bearing housing towards the turbine housing, through the projections of the bearing housing flange, and into the first cover ring of the nozzle ring. This allows for a particularly advantageous mounting of the nozzle ring to the bearing housing.

[0012] According to a further development of the invention, the nozzle ring is connected to a flange of the insert via a second cover ring of the same and to a flange of the insert itself. These second fastening means penetrate the flange of the insert and engage with the second cover ring of the nozzle ring, preferably such that the second fastening means extend axially from the turbine housing towards the bearing housing, through the flange of the insert, and into the second cover ring of the nozzle ring. These features allow for a particularly advantageous mounting of the insert on the nozzle ring.

[0013] According to a further development of the invention, the turbine inlet housing is attached to the bearing housing independently of the nozzle ring via separate fastening means. This is preferred to ensure a good sealing effect of the connection between the turbine inlet housing and the bearing housing and thus to prevent undesirable leakage of the first medium, which is to be expanded in the turbine, into the environment.

[0014] Preferred embodiments of the invention are described in the dependent claims and the following description. Exemplary embodiments of the invention are explained in more detail with reference to the drawing, without being limited thereto. The drawing shows: Fig. 1: a partial cross-section in axial direction through a turbocharger according to the invention in the area of ​​a turbine and a bearing housing; Fig. 2: a perspective view of the arrangement of Fig. 1 with an insert piece shown only partially, as well as a turbine inlet housing shown only partially; Fig. 3: the arrangement of Fig. 2 with nozzle ring also only partially shown.

[0015] The invention relates to a turbocharger. A turbocharger has a turbine for expanding a first medium, in particular the exhaust gas of an internal combustion engine. Furthermore, a turbocharger has a compressor for compressing a second medium, in particular charge air, using energy recovered in the turbine during the expansion of the first medium. The turbine has a turbine housing and a turbine rotor. The compressor has a compressor housing and a compressor rotor. The compressor rotor is coupled to the turbine rotor via a shaft, which is supported in a bearing housing. The bearing housing is positioned between the turbine housing and the compressor housing and is connected to both. This basic design of a turbocharger is familiar to those skilled in the art.

[0016] Fig. 1, Fig. 2 to Fig. Figure 3 shows different views of a section of a turbocharger in the area of ​​a turbine 1 and a bearing housing 2. The turbine 1 comprises a turbine housing 3 and a turbine rotor 6. A compressor of the turbocharger (not shown) has a compressor housing and a compressor rotor, the turbine rotor 6 being coupled to the compressor rotor (not shown) via a shaft 7, which is rotatably mounted in the bearing housing 2. The turbine 1 of the turbocharger is designed as a radial turbine. For the purposes of this invention, radial turbines also include so-called mixed-flow turbines, in which the gas flows in a radial direction, but not only exactly perpendicular to the shaft 7, but at an angle to the shaft 7.

[0017] The turbine housing 3 comprises a turbine inlet housing 4, which in the illustrated embodiment is double-walled and forms a cooling channel 10 for cooling the turbine inlet housing 4. The first medium to be depressurized, preferably hot exhaust gas, can be supplied to the turbine rotor 6 via the turbine inlet housing 4.

[0018] The turbine housing 3 accommodates an insert 5 and a nozzle ring 9. The nozzle ring 9 has guide vanes 11, which serve to guide the flow of the first medium to be depressurized upstream of the turbine rotor 6. The turbine rotor 6 is bladed with rotor blades 8, which are therefore positioned downstream of the guide vanes 11 of the nozzle ring 9 when viewed in the direction of exhaust gas flow. Downstream of the nozzle ring 9, the insert 5, radially adjacent to the rotor blades 8 of the turbine rotor 6, defines the flow channel for the first medium, whereby the depressurized first medium can be discharged from the turbine 1 via the insert 5.

[0019] In the turbocharger according to the invention, the nozzle ring 9 is connected to a first cover ring 12 thereof via first fastening means 13 to a flange 14 of the bearing housing 2, wherein several radially outward extending projections 15 are formed on the flange 14 of the bearing housing 2, to which the first cover ring 12 of the nozzle ring 9 is connected, distributed over the circumference thereof.

[0020] These projections 15 can also be referred to as tabs or rosettes. The first fastening elements 13 penetrate these tab-like or rosette-like projections 15 of the flange 14 of the bearing housing 2 and engage the first cover ring 12 of the nozzle ring 9.

[0021] According to Fig. In the axial direction, the first fastening means 13 extend from the bearing housing 2 towards the turbine housing 3, through the projections 15 of the flange 14 of the bearing housing 2, and into the first cover ring 12 of the nozzle ring 11. The first fastening means 13 are preferably designed as threaded bolts, which have an external thread on those sections extending into the first cover ring 12 of the nozzle ring 9. These external threads engage with corresponding internal threads in threaded bores 16 of the first cover ring 12 of the nozzle ring 9. Opposite sections of these threaded bolts, which project axially from the flange 14 or the projections 15 formed on the flange 14 of the bearing housing 2, also have an external thread. This external thread interacts with corresponding nuts 24 to securely and easily mount the nozzle ring 9 to the bearing housing 2.The nuts 24 are supported on the flange 14 of the bearing housing 2 via sleeves 25. The sections of the threaded bolts that extend through the tab-like or rosette-like projections 15 of the flange 14 of the bearing housing 2 and are arranged between the sections of the threaded bolts carrying the external threads are preferably unthreaded.

[0022] The nozzle ring 9 is connected to a second cover ring 17 opposite the first cover ring 12 via second fastening means 18 to a flange 19 of the insert piece, wherein the second fastening means 18 penetrate the flange 19 of the insert piece 15 and engage with the second cover ring 17 of the nozzle ring 9. The second fastening means 18, which are preferably threaded bolts, extend axially from the turbine housing 3 towards the bearing housing 2 through the flange 19 of the insert piece 5 and into the second cover ring 17 of the nozzle ring 9.

[0023] While the first fastening means 13, which serve to fasten the nozzle ring 9 to the bearing housing 2, extend axially from the bearing housing 2 towards the turbine housing into the first cover ring 12 of the nozzle ring 9, the second fastening means 18 extend rotated by approximately 180° or in the opposite axial direction from the insert 5 or from the turbine housing 3 towards the bearing housing 2 into the second cover ring 17 of the nozzle ring 9.

[0024] As already explained, the second fastening means 18 are again preferably threaded bolts which have external threads on opposing sections, namely a first external thread on the first section, which engages in corresponding threaded bores 20 of the second cover ring 17 of the nozzle ring 9, and further external threads on opposing second sections, which cooperate with a nut 26 to fasten the insert 5 to the nozzle ring 9. These nuts 26 are supported on the flange 19 of the insert 5 via sleeves 27. Between these sections of the threaded bolts bearing the external threads, the sections extending through the flange 19 of the insert 5 are preferably unthreaded.

[0025] The turbine inlet housing 4 of the turbine housing 3 is attached to the bearing housing 2 independently of the nozzle ring 9 and independently of the insert 5, in the illustrated embodiment of the Fig. 1, Fig. 2 to Fig. 3 such that a clamping ring 23 engages adjacent flanges 21, 22 of bearing housing 2 and turbine inlet housing 4.

[0026] In contrast to such a clamping ring 23, the adjacent flanges 21, 22 of bearing housing 2 and turbine inlet housing 4 can also be connected to each other via a clamping jaw connection and / or screw connections.

[0027] In the turbocharger according to the invention, the nozzle ring 9 is attached to the bearing housing 2 by means of first fastening means 13, which interact on the one hand with the flange 14 of the bearing housing 2 and on the other hand with the first cover ring 12 of the nozzle ring 9, specifically by penetrating the radial projections 15 of the flange 14, which can also be referred to as tabs or rosettes, in the area of ​​the flange 14 of the bearing housing 2. These projections 15 can expand together with the nozzle ring 9, thereby minimizing stresses in the connection between the bearing housing 2 and the nozzle ring 9. The insert 5 is attached to the nozzle ring 9 by means of second fastening means 18. The turbine inlet housing 4 is mounted on the bearing housing 2 independently of this.For assembly, the insert 5 is first mounted on the nozzle ring 9 using the second set of fasteners 18, and then the pre-assembled unit consisting of insert 5 and nozzle ring 9 is attached to the bearing housing 2 using the first set of fasteners 13. Following this, the turbine inlet housing 4 can be mounted on the bearing housing 2. Reference symbol list 1 Turbine 2 bearing housings 3 turbine housings 4 turbine inlet housings 5 insert pieces 6 turbine rotor 7th wave 8 Running blade 9 nozzle ring 10-channel 11 Guide vane 12 Deck ring 13 Fasteners 14 flange 15 lead 16 threaded holes 17 Deck ring 18 Fasteners 19 flange 20 threaded holes 21 Flange 22 flange 23 Fasteners 24 Mother 25 sleeve 26 Mother 27 Sleeve

Claims

Turbocharger, comprising a turbine (1) for expanding a first medium, comprising a compressor for compressing a second medium using energy gained in the turbine (1) during the expansion of the first medium, wherein the turbine (1) comprises a turbine housing (3) and a turbine rotor (6), wherein the compressor comprises a compressor housing and a compressor rotor coupled to the turbine rotor (6) via a shaft (7), wherein the turbine housing (3) and the compressor housing are each connected to a bearing housing (2) arranged between them, in which the shaft (7) is supported, wherein the turbine housing (3) comprises a turbine inlet housing (4) and accommodates an insert (5) and a nozzle ring (9) with guide vanes (11), characterized in that the nozzle ring (9) is connected to a flange (14) of the bearing housing (2) via first fastening means (13) on a first cover ring (12) thereof.wherein several radially outwardly extending projections (15) are formed around the circumference of the flange (14) of the bearing housing (2), to which the first cover ring (12) of the nozzle ring (9) is connected, wherein the first fastening means (13) penetrate the projections (15) of the flange (14) of the bearing housing (2) and engage with the first cover ring (12) of the nozzle ring (9). Turbocharger according to claim 1, characterized in that the first fastening means (13) extend axially from the bearing housing (2) towards the turbine housing (3) through the projections (15) of the flange (14) of the bearing housing (2) into the first cover ring (12) of the nozzle ring (9). Turbocharger according to claim 1 or 2, characterized in that the nozzle ring (9) is connected to a flange (19) of the insert (5) via second fastening means (18) on a second cover ring (17) thereof, wherein the second fastening means (18) penetrate the flange (19) of the insert (5) and engage with the second cover ring (17) of the nozzle ring (9). Turbocharger according to claim 3, characterized in that the second fastening means (18) extend axially from the turbine housing (3) towards the bearing housing (2) through the flange (19) of the insert (5) into the second cover ring (17) of the nozzle ring (9). Turbocharger according to one of claims 1 to 4, characterized in that the turbine inlet housing (4) is attached to the bearing housing (2) independently of the nozzle ring (9) via a separate fastening means (23). Turbocharger according to one of claims 1 to 5, characterized in that the turbine (1) is a radial turbine.

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