An exhaust-gas turbocharger (1) with a bearing housing (2), a shaft (3) mounted in the bearing housing (2), a compressor wheel (5) arranged on the shaft (3) and a turbine wheel (4) arranged on the shaft (3), a housing component (7) which surrounds the compressor wheel (5) or the turbine wheel (4), and a sealing ring (14) between the bearing housing (2) and the housing component (7), wherein the sealing ring (14) is, in order to impart its sealing action, compressed in a direction perpendicular to the shaft (3).

The invention relates to an exhaust-gas turbocharger according to the preamble of claim1and to a method for the assembly of an exhaust-gas turbocharger.

FIG. 4shows an exhaust-gas turbocharger100according to the prior art. A section through the entire exhaust-gas turbocharger100is illustrated on the left-hand side. The right-hand illustration shows a detail. The housing of the already-known exhaust-gas turbocharger100is composed of a bearing housing102in which a shaft103is mounted. On one side, the bearing housing102is closed off by a compressor housing108. On the other side of the bearing housing102, there is situated a turbine housing107. The detail illustration shows the connection between the bearing housing102and the turbine housing107. The turbine housing107is normally fixedly connected to the bearing housing102by means of a screw connection126. A sealing ring114is situated between the two housing components. The sealing ring is of V-shaped form. The V-shaped form opens in a direction perpendicular to the shaft103. In already-known turbochargers100, an axially sealing shaped sealing ring (for example the sealing ring114) or alternatively a half-bead seal is used for sealing the connecting point between the turbine housing107and the bearing housing103. Since both variants are constructed axially, screw forces of the screw connection126are also required to compress the seal. The action of the seals is based on their linear pressure, which is highly dependent on the number, size and tightening torque of the screw connections126. Owing to packaging requirements and the provision of tool access for the screwdrivers during assembly, a compromise is usually reached between assemblability and sealing action.

It is therefore an object of the present invention to specify an exhaust-gas turbocharger as per the preamble of claim1, the housing components of which are sealed off with respect to one another in as effective a manner as possible, wherein the exhaust-gas turbocharger should be inexpensive to produce and assemble. It is also an object to specify a corresponding method for assembling the exhaust-gas turbocharger.

This object is achieved in each case by the features of the independent claims. The dependent claims relate to preferred refinements of the invention.

According to the invention, the sealing ring is no longer compressed axially. It is in fact provided according to the invention that the sealing ring, in order to impart sealing action, is compressed in a direction perpendicular to the shaft, that is to say in a radial direction. According to the invention, said arrangement is used for a sealing ring between the bearing housing and a housing component. The housing component may be either the turbine housing or the compressor housing. It is crucial that the sealing ring is formed and arranged such that the corresponding deformation for producing the sealing action at the sealing ring has already been generated before the axial screw connection is established.

As a result of the radial arrangement, or radial compression of the sealing ring, according to the invention, influence is no longer exerted on the screw forces of the screw connection for connecting the bearing housing to the housing component. The screw forces can thus be used entirely for the bracing of the bearing housing to the housing component. Since the sealing ring, to impart its sealing action, no longer requires screw forces which were required in the prior art in order to generate an adequately high linear pressure on the sealing ring, it is possible for some screws to be omitted and/or to be arranged such that the screws are distributed non-uniformly, in order to ensure easier accessibility during the assembly process. The assembly time is also reduced in this way. Since the sealing ring according to the invention is pushed on, centered at the inside or at the outside, before the bearing housing and the housing component are fitted together, captive installation is automatically also ensured such that assembly and process capability are optimized.

As a result of the use of the sealing ring according to the invention, there is no longer a compromise between sealing action and assemblability, and any requirement can be individually designed for in an optimum manner.

It is expedient for the sealing ring to be arranged between the bearing housing and the turbine housing, and thus prevent an escape of exhaust gas. It is however also provided for the sealing ring to be used between the bearing housing and compressor housing.

In the method according to the invention, it is important that the sealing ring is deformed in a radial direction by the pushing-together of bearing housing and housing component. Only thereafter is the screw connection of the housing established.

A first exemplary embodiment of an exhaust-gas turbocharger1will be described below on the basis ofFIGS. 1 and 2.FIG. 3shows a detail of the exhaust-gas turbocharger1according to a second exemplary embodiment.

AsFIG. 1shows, the housing of the exhaust-gas turbocharger1is assembled from three main components. A bearing housing2is situated in the middle. A shaft3is rotatably mounted in said bearing housing2. A turbine housing7and a compressor housing8are flange-mounted on the bearing housing2. Seated on the shaft3on one side is a turbine wheel4. A compressor wheel5is seated on the other side. An inflow duct9for exhaust gas is formed in the turbine housing7. A discharge duct10for compressed air is formed in the compressor housing8.

Exhaust gas that flows in via the inflow duct9drives the turbine wheel4. Connected via the shaft3, the compressor wheel5also rotates with the turbine wheel4. The compressor wheel5sucks in air and discharges the compressed air via the discharge duct10.

The turbine housing7and the compressor housing8are also referred to generally as “housing component”. Below, reference is made in particular to the seal between the housing component and the bearing housing2. Here, the exemplary embodiments show the seal between the turbine housing7and the bearing housing2, because it is at this location in particular that the seal is used advantageously.

FIG. 2shows the flange between the bearing housing2and turbine housing7. For precise assembly, a centering pin12is provided which extends both into the bearing housing2and also into the turbine housing7. A screw connection (not illustrated) between the turbine housing7and the bearing housing2runs parallel to said centering pin12.

In each case one groove is formed in the bearing housing2and in the turbine housing7. Said two grooves are arranged such that, in the assembled state, they form a cavity13. Said cavity13is formed around the full circumference of the shaft3. In the cavity13there is seated a sealing ring14, formed as a V-shaped shaped sealing ring.

For simplicity of the illustration,FIG. 2shows not the entire shaft3but rather only the longitudinal axis15of the shaft3. The V-shape of the sealing ring14opens in a direction parallel to the shaft3or to the longitudinal axis15of the shaft3.

The sealing ring14is squeezed or compressed between a first annular surface16and a second annular surface19. The two annular surfaces16,19are parallel to the shaft3. The first annular surface16is formed on the bearing housing2. The second annular surface19is formed on the turbine housing7. The sealing ring14is deformed between the two annular surfaces16,19, and thus imparts its sealing action, independently of a bracing action generated for example by a screw connection in a longitudinal direction of the shaft3. This can therefore also be referred to as a radial arrangement of the sealing ring14.

The groove for receiving the sealing ring14in the bearing housing2is formed by the first annular surface16. The first annular surface16is delimited on one side by a first wall17which is formed as a small shoulder. On the other side, the first annular surface16is delimited by a second wall18. As a result of this configuration, the sealing ring14can be pushed onto or pre-mounted on the bearing housing2before the bearing housing2and turbine housing7are joined together. The sealing ring14is prevented from falling off by the first wall17.

A bevel20is formed on the second annular surface19. Said bevel20prevents damage to the sealing ring14when the bearing housing2and turbine housing7are pushed together.

A cavity height21is indicated inFIG. 2. The cavity height21is perpendicular to the shaft3. Also shown is a cavity width22and a sealing ring width23. The cavity width22and the sealing ring width23are parallel to the shaft3. The cavity width22is greater than the sealing ring width23. There is thus no deformation of the sealing ring14as a result of compression in an axial direction of the shaft3. In the unmounted state, that is to say before the bearing housing2and the turbine housing7have been pushed together, a height of the sealing ring14is greater than the illustrated cavity height21. The sealing ring14is compressed to the cavity height21, and thus imparts its sealing action, only as a result of the pushing-together of the bearing housing2and turbine housing7.

FIG. 3shows the second exemplary embodiment in detail. Identical or functionally identical components are denoted by the same reference numerals in all of the exemplary embodiments. By contrast to the first exemplary embodiment, the groove in the bearing housing2has a wall24situated opposite the first annular surface16. The width25of the opposite wall24, measured parallel to the shaft3, is significantly smaller than the overall cavity width22. Said design according to the second exemplary embodiment increases the size of the cavity13and thus permits the insertion of a relatively large sealing ring14.

In the method according to the invention for the assembly of the exhaust-gas turbocharger1according to the first or second exemplary embodiment, it is crucial that the sealing ring14is compressed as the bearing housing2and turbine housing7are pressed together. Here, the force exerted on the sealing ring14is in a direction perpendicular to the shaft3. Only after the sealing ring14has been completely deformed is a conventional screw connection, such as is illustrated for example at reference sign126inFIG. 4, established. According to the invention, however, said screw connection has no effect whatsoever on the sealing ring14, and also does not alter the sealing action of the sealing ring14.

In addition to the above written description of the invention, reference is hereby explicitly made to the diagrammatic illustration of the invention inFIGS. 1 to 3for additional disclosure thereof.

LIST OF REFERENCE SIGNS