DE102015209929A1 - Impeller housing for an exhaust gas turbocharger with a valve seat ring having a bypass valve and exhaust gas turbocharger and assembly method - Google Patents

Abstract

The invention relates to an impeller housing (10) for an exhaust gas turbocharger for an internal combustion engine, which has a bypass valve (20) with a valve flap (21) and a valve seat (15) having a valve seat ring (30), and with at least one such impeller housing (10) equipped exhaust gas turbocharger (1), and a mounting method for mounting the impeller shell (10) with valve seat ring (30) in the valve seat (15) of the bypass valve (20). Here, the impeller housing (10) is characterized in that the valve seat ring (30) has a deformation region (34) in which the material of the valve seat ring (30) by a subsequent forming process in a deformation region (34) corresponding radial undercut (17) of a Receiving formation (16) of the bypass channel (13) is displaced, whereby the valve seat ring (30) is permanently fixed in the receiving formation (16).

Description

The invention relates to an impeller housing for an exhaust gas turbocharger for an internal combustion engine having a bypass valve with a valve flap and a valve seat having valve seat, as well as equipped with at least one such impeller exhaust gas turbocharger, and a mounting method for mounting the impeller housing with valve seat ring in the valve seat of the bypass valve.

Exhaust gas turbochargers are increasingly used to increase performance in automotive internal combustion engines. This happens more often with the aim of reducing the internal combustion engine with the same or even increased performance in size and weight while reducing consumption and thus the CO ₂ emissions, in view of increasingly stringent legal requirements in this regard. The operating principle is to use the energy contained in the exhaust gas flow to increase the pressure in the intake tract of the engine and thus to better fill the combustion chamber with air-oxygen and thus to be able to convert more fuel, gasoline or diesel, per combustion process, ie to increase the performance of the internal combustion engine.

An exhaust gas turbocharger has for this purpose a turbine arranged in the exhaust gas line of the internal combustion engine with a turbine runner driven by the exhaust gas flow and a compressor arranged in the intake tract with a compressor runner building up the pressure. Turbine impeller and compressor impeller are rotatably secured to the opposite ends of a rotor shaft, which is rotatably mounted in a bearing assembly disposed between the turbine and compressor. Thus, with the aid of the exhaust gas mass flow, the turbine wheel and, in turn, the compressor wheel are driven via the rotor shaft and the exhaust gas energy is thus used to build up pressure in the intake tract.

The operation of an internal combustion engine in a motor vehicle is characterized by dynamic changes of the load and the operating range.

In order to be able to adapt the operating range of the exhaust gas turbocharger to changing operating ranges of the internal combustion engine and thus to ensure a desired response as far as possible without noticeable delays (turbo lag), turbochargers with so-called variable turbine geometries and with bypass valves disclosed in the impeller housings, ie in turbine housings and compressor housing.

A corresponding bypass valve on the turbine side is called a wastegate valve. The wastegate valve connects the exhaust duct upstream of the turbine runner via a wastegate duct to the exhaust duct downstream of the turbine runner and can be opened or closed via a closing device, for example a valve flap interacting with a valve seat.

A corresponding bypass valve on the compressor side is referred to as a diverter valve. The diverter valve connects the fresh air intake duct in the direction of flow in front of the compressor impeller via a thrust air duct with the compressed air duct in the flow direction after the compressor impeller and, like the wastegate valve, can open via a closing device, for example a valve flap cooperating with a valve seat or be closed.

As a closure device for opening and closing of said bypass valves, such as wastegate valves and diverter valves, flap valves are used in a known manner. An example of a conventional impeller shell with such a bypass valve 20 in the prior art is in 1 in a schematic sectional view of a turbine housing 10 using a wastegate valve 20 shown with a crank arm actuator.

Over the fluid inlet area 11 of the impeller housing 10 , here a turbine housing, the fluid mass flow FM, in this case an exhaust gas mass flow, enters the impeller housing 10 the exhaust gas turbine. From the impeller housing 10 the exhaust gas mass flow FM is directed to the turbine wheel (not shown) and then passes through the fluid outlet area 12 in the exhaust system (not shown) and through this into the environment. The bypass channel 13 , here a wastegate channel, now connects directly to the fluid inlet area 11 with the fluid exit area 12 , The valve seat 15 of the bypass channel 13 has a separately inserted valve seat ring 30 with a valve seat surface 31 on. The valve seat ring is with respect to the flow direction of the fluid mass flow FM at the bypass channel output 14 arranged. To close the bypass channel 13 becomes a plate-shaped valve flap 21 on the valve seat surface 31 of the valve seat ring 30 hung up. The valve flap 21 is on a crank arm 22 fixed on a crank spindle 23 is mounted and thus to the crank spindle axis of rotation 24 is rotatably mounted. By turning the crank arm 22 around the crank spindle axis of rotation 24 (clockwise in the drawing) the valve flap 21 along the valve flap path, approximately with respect to the valve seat surface 31 vertical direction, on the valve seat ring 30 mounted and the bypass channel 13 , here the wastegate channel, so closed and opened in the opposite direction.

Such bypass valves are in the mass flow FM of the exhaust gas or the intake air of the internal combustion engine and are exposed to fluctuating pressure and temperature conditions. This applies especially to the wastegate valve, which can be exposed to temperatures of up to 1200 ° C. However, even in the area of a recirculating-air valve, the temperature increase of the charge air during compression can cause temperatures of more than 100 ° C.

Furthermore, high demands are placed on the tightness of the bypass valves in the closed state, resulting in a flat, tight resting of the valve flap 21 on the valve seat surface 31 requires and the application requires correspondingly high closing forces. Due to the fluctuating operating temperatures and the associated different thermal expansions in the system, it is advantageous to mount the valve flap 21 on the associated actuating device, for example on the corresponding crank arm 22 to equip with a certain game.

Such or similar designs of bypass valves are also in the documents, for example DE 10 2008 011 416 A1 . DE 10 2010 007 600 A1 and DE 100 20 041 C2 disclosed.

In modern exhaust gas turbochargers for internal combustion engines in motor vehicles, for example, for weight and cost reasons, among other things, aluminum or other light metals, such as magnesium, used as a material for the thermal turbine housing very highly loaded. The problem is that aluminum at high temperatures loses its strength. In particular, in operating points of the exhaust gas turbine with high exhaust gas mass flows, in the full load range, a portion of the exhaust gas is passed over the partially or fully opened wastegate valve past the turbine. This leads to very high temperatures in the region of the wastegate valve, in particular the valve flap and the valve flap seat 15 , This leads to the softening of the aluminum material in these areas. If the wastegate valve is then regulated to a position at which the valve flap 21 just before resting on the valve seat surface 31 is located, it is mainly by the pressure pulsations of the charge change to a "prancing" of the valve flap 21 as part of the game between the valve flap 21 and crank arm 22 , This "dancing" leads to pulsating movements and impacts of the valve flap 21 on the valve seat surface 31 What, without a corresponding valve seat ring 30 inevitably to increased wear to the local deformation of the valve seat 31 can lead. As a result, the wastegate valve would leak and the exhaust gas turbocharger and thus the engine loses power. The speed of the torque buildup of the internal combustion engine is adversely affected.

These relationships apply in principle also for diverter valves, although the problem does not seem so urgent due to the lower temperatures.

For this reason, for example when using a "soft" housing material, for example, a separate valve seat ring 30 as a valve seat 15 at the bypass channel output 14 the respective impeller housing used, which consists of a heat-resistant material higher wear resistance, for example steel.

The attachment of the valve seat ring 30 in the valve seat 15 of the respective bypass channel 13 takes place according to the known prior art by means of a press connection by shrink or press or by caulking the valve seat ring 30 surrounding material or by pouring the valve seat ring in the casting process of the housing, see for example DE 10 2010 062 403 A1 ,

Now it comes in the operation of the exhaust gas turbocharger to temporally changing temperature fluctuations and sometimes steep temperature gradient in the valve seat. Not least Due to the different thermal expansion of the valve seat ring made of steel, for example, and of the surrounding material of the valve seat, however, in the case of the abovementioned known fastening types, the valve seat ring may temporarily or even permanently loosen or even loosen. The consequences that result from the loss of power of the exhaust gas turbocharger due to increased leakage up to destruction of the exhaust gas turbocharger.

The task resulting for the person skilled in the art is now to provide an impeller housing for an exhaust gas turbocharger, which, even when mating different materials, a reliable and resistant to high temperatures and temperature fluctuations connection and fixation of a valve seat ring in the respective valve seat of a bypass valve in the respective Impeller housing, and thus increases the reliability of the exhaust gas turbocharger.

Furthermore, this results in the task of specifying an exhaust gas turbocharger, the at reduced total weight has high reliability and long life.

The object is further to provide an assembly method for an impeller housing of the exhaust gas turbocharger according to the invention, with a permanent and reliable fixation of the valve seat ring in the respective valve seat of a bypass valve in the respective impeller housing can be made in a simple and cost-effective manner.

This object is achieved by an impeller housing with the features according to claim 1, an exhaust gas turbocharger according to the independent device claim and a mounting method for mounting the valve seat ring according to the independent method claim. Advantageous embodiments and developments, which can be used individually or in combination with each other, are the subject of the dependent claims.

The impeller housing according to the invention for an exhaust gas turbocharger of an internal combustion engine consists of a light metal material and has a bypass channel which can be closed by a valve flap. The bypass channel has a valve seat on which is equipped with a valve seat ring. The valve seat ring has a valve seat surface on the side which faces the valve flap of the bypass valve and is arranged in a receiving formation at the bypass channel outlet in which it extends axially from the valve seat surface, ie in the direction of the bypass valve. Channel centerline, extending into the bypass channel.

Here, the impeller housing is characterized in that the valve seat ring in a spaced from the valve seat surface in the axial direction region, a deformation region which extends over a deformation ring height, ie over a certain axial portion of the overall ring height, and in which the material the valve seat ring is displaced by a subsequent forming process in a radial undercut corresponding to the deformation region of the receiving formation of the bypass channel, whereby the valve seat ring is permanently fixed in the receiving molding.

In this case, the ring height characterizes the axial extension of the valve seat ring or a certain portion thereof in the direction of the annular central axis. Thus, the overall ring height characterizes the axial extent of the valve seat ring as a whole, that is, starting from the valve seat surface in the axial direction to the opposite end of the valve seat ring and the deformation ring height, the axial extent of the deformation region as part of the overall ring height.

A radial undercut of the receiving recess is characterized in that the receiving recess from a given viewing point on the central axis of the recess and above the valve seat surface in a farther away from the viewing point section with respect to the central axis has a greater radial extent than in a closer lying at the viewing point Section. At the same time, the center axis of the receiving recess provides the joining direction in which the valve seat ring can / must be inserted into the receiving recess.

By subsequent deformation, ie after insertion of the valve seat ring in its intended position in the receiving recess, and the displacement of the material of the valve seat ring in the deformation region corresponding radial undercut thus a positive connection between the valve seat ring and receiving recess is made and the valve seat ring fixed in this position and permanently secured against falling out or pulling in reverse joining direction.

Corresponding embodiments of the object according to the invention provide that the impeller housing is a turbine housing and the associated bypass channel is a wastegate channel of the exhaust gas turbocharger or that the impeller housing is a compressor housing and the associated bypass channel is a thrust air duct of the exhaust gas turbocharger.

This has the advantage that the turbine housing and / or the compressor housing of an exhaust gas turbocharger can be performed as needed according to the impeller housing according to the invention and so the weight can be reduced as needed with increased reliability.

The exhaust gas turbocharger according to the invention for an internal combustion engine is characterized in that it comprises at least one impeller housing according to one of claims 1 to 10. Accordingly, at least the turbine housing or the compressor housing or even the turbine housing and the compressor housing of the exhaust gas turbocharger according to the invention each consist of a light metal material and each have a closable with a valve flap bypass channel with a valve seat ring according to the above-described embodiment.

This has the advantage that for the turbine housing and / or the compressor housing a lighter weight light metal material can be used to save weight and yet no increased wear of the valve seat has to be taken into account.

The assembly method according to the invention for an impeller housing of an exhaust gas turbocharger according to the above description is characterized by the following method steps.

First, a valve seat ring is provided which has a valve seat surface and a spaced from the valve seat surface in the axial direction deformation region.

Simultaneously with the aforementioned step, the provision of an impeller housing made of a light metal material for an exhaust gas turbocharger, with a bypass channel having a receiving recess for the valve seat ring with a radial undercut in a corresponding to the deformation region of the valve seat ring area at the bypass channel output, respectively.

Following this, the insertion and positioning of the valve seat ring in the axial direction, ie with the central axis of the valve seat ring in the direction of the central axis of the Aufnahmeausformung, takes place in the Aufnahmeausformung the bypass channel output.

Finally, the permanent fixing of the valve seat ring takes place in the receiving formation of the bypass channel output by displacement of material of the valve seat ring in the said deformation region in the radial direction in the said corresponding radial undercut of Aufnahmeausformung.

The assembly method described is applicable to all previously and subsequently described embodiments of the exhaust gas turbocharger.

This method has the further advantage that it is easy to carry out and inexpensive and still ensures a secure and permanent fixation of the valve seat ring in the impeller housing.

Further embodiments of the invention are explained in more detail below with reference to the illustrations in the drawing.

Show it:

1 a simplified sectional view of an impeller housing with a bypass valve and an inserted valve seat ring, according to the prior art;

2 an enlarged view of the detail X from 1 showing a sectional view of the valve flap seat of an embodiment of the impeller housing according to the invention.

3 another enlarged view of the detail X from 1 showing a sectional view of the valve flap seat of another embodiment of the impeller housing according to the invention.

4 a further enlarged sectional view of a valve flap seat of an embodiment of the impeller housing according to the invention.

5A) a further enlarged sectional view of a valve flap seat of an embodiment of the impeller housing according to the invention with a material thickening in the deformation region, before the material displacement in the undercut of the Aufnahmeausformung.

5B) the sectional view of the 5A) after the material displacement in the undercut of the receiving formation.

6 a simplified representation of an exhaust gas turbocharger according to the invention.

7 a sectional view through the valve seat and a forming tool immediately prior to the forming process to displace the deformation region of the valve seat ring in the radial undercut of the Aufnahmeausformung.

8th a flow diagram of the individual process steps of the assembly process of the impeller housing.

Function and designation same parts are designated in the figures with the same reference numerals.

The 1 serves to explain the prior art and has already been described above in this context.

In the enlarged sectional view of the detail X of the impeller housing is the valve seat 15 an embodiment of an impeller housing according to the invention shown. You can see a section of the impeller housing 10 with a receiving formation 16 with a valve seat ring received therein 30 , The valve seat ring 30 indicates on the valve flap (not shown, see 1 ) facing side a valve seat surface 31 on. Starting from the valve seat surface 31 extends the valve seat ring 30 in the axial direction, ie in the direction of the ring axis A, over its total ring height HG, from the bypass channel output 14 forth in the Aufnahmeausformung 16 in the bypass channel 13 , At the lower end sits the valve seat ring 30 on one in the receiving formation 16 provided axial stop 35 on, causing it in the axial direction in the receiving formation 16 is positioned.

The valve seat ring 30 has one of the valve seat surface 31 in the axial direction spaced deformation region 34 on, which extends over a deformation ring height HV and in which the material of the valve seat ring 30 by a subsequent forming process in a deformation area 34 corresponding radial undercut 17 the Aufnahmeausformung the bypass channel is displaced. This is the valve seat ring 30 permanently in the receiving formation 16 fixed and can not be removed without destruction. The distance of the deformation area 34 of the valve seat is to be chosen so that the seal with the valve flap 21 provided valve seat surface 31 by displacing the valve seat ring material into the radial undercut 17 the Aufnahmeausformung 16 required deformation of the deformation area 34 no influence on the flatness and position of the valve seat surface 31 ,

For exact, concentric positioning and additional sealing between the valve seat ring 30 and receiving molding 16 it is advantageous if the outer contour of the valve seat ring 30 with the corresponding inner contour of the Aufnahmeausformung 16 create a fit with the least possible play or even a press fit. This fit can over the entire ring height HG or even over only a part of the total ring height HG, one below as fit range 33 designated, over a fitting ring height HP extending portion, be provided.

The valve seat ring 30 points in the example of the 2 a constant ring thickness DR. In further embodiments, the valve seat ring 30 However, in different axial sections have quite different ring thicknesses. For example, it may be provided that in the fit range 33 a matching fit ring thickness DP is provided.

So shows 3 another example of the execution of the valve seat ring 30 an impeller housing according to the invention 10 , The in 3 illustrated valve seat ring 30 points away from the valve seat surface 31 in the axial direction, first of all, a fitting region extending over a specific fitting ring height HP 33 with a certain fit ring thickness DP. In addition to the fit range, the valve seat ring 30 a forming area 32 on, in the axial direction to the fit range 33 connects, extends axially over a forming ring height HU and has a forming ring thickness DU. In this example, the deformation range is still 34 at the lower end of the forming area 32 and thus at the bottom of the valve seat ring 30 arranged.

In further variations of this design example, the deformation range 34 extend at least over part of its deformation ring height HV within the forming ring height HU and can, however, even into the fit range 33 over rich.

This embodiment has the advantage that the ring thickness DR in the different areas can be adapted to the respective requirements. So can in the fit range 33 a larger fit-ring thickness DP can be chosen to be in case of a press fit 36 , as in 3 indicated to ensure greater dimensional stability of the valve seat ring. In the forming area 32 On the other hand, a smaller forming ring thickness DU can be helpful for a gentler forming and material displacement within the forming area 32 positioned deformation area 34 to ensure a lower forming effort.

In particular, the embodiment of the 3 characterized in that the valve seat ring 30 in his pass range 33 has a cylindrical outer contour which is a press fit 36 with the corresponding inner contour of the Aufnahmeausformung 16 of the bypass channel 13 having.

In addition, the in 3 illustrated valve seat ring 30 characterized by the further embodiment feature that the radial outer contour of the valve seat ring in the transition between the fit range 33 and the transformation area 32 , tapered stepwise and with a corresponding tapering of the receiving formation 16 of the bypass channel 13 as an axial stop 35 for defined axial positioning of the valve seat ring 30 in the impeller housing 10 interacts.

In addition, a shows in 4 shown another example of the execution of the valve seat ring 30 an impeller housing according to the invention 10 , a valve seat ring 30 who is the one who 3 However, in contrast to this, the deformation range comes close 34 not at the lower end of the forming area 32 is arranged centrally in it. Furthermore, in the transition between the pass range 33 and the transformation area 32 trained rejuvenation here not stepped but cone-shaped. This has the advantage of effecting additional centering of the valve seat ring during assembly. In addition, in both of the above-mentioned forms of rejuvenation an additional stage in the Aufnahmeausformung 16 not required for axial positioning.

The embodiments shown above show that, as required, a wide range of variation of the different Dimensions and dimensions of the valve seat ring 30 and the corresponding receiving formation 16 given is. However, embodiments have proved to be advantageous, which are characterized in that the fit ring height HP to the forming ring height HU is in a ratio of 1/10 to 11/1. Furthermore, regardless of this, a ratio of fitting ring thickness DP to forming ring thickness DU is positive from 1/1 to 20/1, and independently of this, the fitting ring thickness DP can advantageously be chosen to be smaller or equal to the fitting diameter. Ring height HP. On the other hand, it is advantageous for the deformation ring height HV if it is smaller than the sum of the deformation ring height HU and half the fitting ring height HP.

Furthermore, it has been shown to be positive when the valve seat ring 30 consists of a material whose strength value to the corresponding strength value of the light metal material of the impeller housing 10 in a ratio is less than or equal to 6/1.

In 5A) and B) is another example of the embodiment of the valve seat ring 30 an impeller housing according to the invention 10 shown. In this example, the valve seat ring 30 in the deformation area 34 a material thickening 37 on. 5A) shows this material thickening 37 even before the material displacement in the undercut 17 , So in the original state of the valve seat ring 30 in which the material thickening 37 on the inner contour of the valve seat ring 30 is arranged. Based on the arrangement on the inner contour of the valve seat ring 30 becomes the material thickening 37 by the forming process in the undercut 17 the Aufnahmeausformung 16 displaced so that the valve seat ring 30 in the assembled and fixed state has an inner contour with a cylindrical shape, with an inner diameter also substantially constant in the deformation region, as in 5B) can be seen.

6 shows an exhaust gas turbocharger according to the invention, which is essentially a turbine housing 10a with a turbine wheel 9a , a bearing housing 8th and a compressor housing 10b with a compressor impeller 9b having. In the turbine housing 10a is a wastegate channel 13a with a wastegate valve 20a arranged. In the compressor housing 10b is a recirculating air duct 13b with a diverter valve 20b arranged. In the bearing housing 8th the turbocharger rotor is mounted, the compressor impeller and the turbine impeller via a common rotor shaft 8a united. In this embodiment, the turbine housing according to the impeller housing according to the invention 10 executed. The detail X engages the region of the valve flap seat of the wastegate valve 20a out and corresponds to one of the previously described embodiments of the valve seat according to the 2 to 5 ,

7 shows a simplified sectional view through a valve flap seat of an impeller housing according to the invention 10 with inserted valve seat ring according to 5A) even before the deformation of the deformation area provided with a material thickening 34 , Inserted in the valve seat ring 30 is a device for forming the deformation area 34 , here a simplified shown rolling tool 40 , The roller burnishing tool 40 consists essentially of a tool shank 41 , a sleeve-shaped Umformkugelführung rotatably mounted therein about the tool axis AW 42 with incorporated therein spheres 43 and one inside the forming ball guide 42 arranged Abrolldorn 44 , Upon rotation of the forming ball guide 42 around the tool axis AW, the forming balls 43 taken along and roll on the displacement cone 45 of the unwinding mandrel 44 from. By axial displacement of the unwinding mandrel 44 in the Umformkugelführung 42 down, with simultaneous rotation of the Umformkugelführung 42 around the tool axis AW, by means of the displacer cone 45 the forming balls 43 successively moved radially outward and displace the material of the valve seat ring 30 , as it were in a rolling process, radially outward. By appropriate axial positioning of the Umformkugelführung 42 and thus the forming balls 43 relative to the valve seat ring 30 the material becomes the material thickening of the deformation area 34 radially outward into the radial undercut 17 the Aufnahmeausformung 16 repressed.

8th shows the sequence of the assembly method according to the invention for an impeller housing according to the invention. In step B1, the provision of the valve seat ring takes place. Parallel to this, the provision of the impeller housing in step B2 can take place. Subsequently, in step E, the valve seat ring is inserted into the receiving formation of the impeller shell. Depending on the dimensional design while a press fit between valve seat ring and Aufnahmeausformung is generated. In the subsequent step F, the permanent fixing of the valve seat ring takes place in the receiving formation of the bypass channel outlet by displacement of material of the valve seat ring in the said deformation region in the radial direction in the said corresponding radial undercut of Aufnahmeausformung.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102008011416 A1 [0012]
• DE 102010007600 A1 [0012]
• DE 10020041 C2 [0012]
• DE 102010062403 A1 [0016]

Claims (12)

Impeller housing for an exhaust gas turbocharger of an internal combustion engine, wherein the impeller housing consists of a light metal material and having a valve flap closable by-pass channel, said bypass channel has a valve seat which is equipped with a valve seat ring, wherein the valve seat ring on the valve flap side facing a Valve seat surface and is arranged in a receiving formation at the bypass channel output, in which it extends from the valve seat surface in the axial direction in the bypass channel, characterized in that the valve seat ring in a spaced from the valve seat surface in the axial direction a region Deformation has, which extends over a deformation ring height and in which the material of the valve seat ring by a subsequent forming process in a deformation region corresponding to the radial undercut of the receiving formation of the bypass channel is displaced, whereby the valve seat ring is permanently fixed in the Aufnahmeausformung. Impeller housing according to claim 1, characterized in that the impeller housing is a turbine housing and the associated bypass channel is a wastegate channel of an exhaust gas turbocharger or that the impeller housing is a compressor housing and the associated bypass channel is a thrust air passage of the exhaust gas turbocharger. Impeller housing according to one of claims 1 or 2, characterized in that the valve seat ring extends axially over a total annular height and has a fitting region in which the radial outer contour of the valve seat ring has a fit with the corresponding inner contour of the receiving formation, wherein the fitting region axially extends over a fit ring height, at least over a portion of the total ring height and has a fit ring thickness. Impeller housing according to claim 3, characterized in that the valve seat ring next to the fitting region has a forming region which adjoins the fitting region in the axial direction, extends axially over a forming ring height and has a forming ring thickness and wherein the deformation region is at least one Part of its deformation ring height extends within the forming ring height. Impeller housing according to claim 3 or 4, characterized in that the valve seat ring in its fit region has a cylindrical outer contour which has a press fit with the corresponding inner contour of the receiving formation of the bypass channel. Impeller housing according to one of claims 4 or 5, characterized in that the radial outer contour of the valve seat ring in the transition between the fitting region and the transformation region, in particular stepped or conical, tapers and defined with a corresponding taper of the receiving formation of the bypass channel as an axial stop axial positioning of the valve seat ring in the impeller housing cooperates. Impeller housing according to one of claims 4 to 6, characterized in that the fit ring height to the forming ring height is in a ratio of 1/10 to 11/1 and regardless of the fit ring thickness to the forming ring thickness in a ratio of 1 / 1 to 20/1 and regardless of the fit ring thickness is smaller or equal to the fit ring height. Impeller housing according to one of claims 4 to 7, characterized in that the deformation ring height is smaller than the sum of forming ring height and the half fitting ring height. Impeller housing according to claim 8, characterized in that the valve seat ring in the deformation region has a material thickening, which is displaced starting from an arrangement on the inner contour of the valve seat ring in the undercut of Aufnahmeausformung so that the valve seat ring in the assembled state an inner contour with a cylindrical shape, having a substantially constant in the deformation range inside diameter. Impeller housing according to one of claims 1 to 9, characterized in that the valve seat ring consists of a material whose strength value to the corresponding strength value of the light metal material of the impeller housing is in a ratio of less than or equal to 6/1. Exhaust gas turbocharger for an internal combustion engine, characterized in that it comprises at least one impeller housing according to one of claims 2 to 10. Assembly method for an impeller housing of an exhaust gas turbocharger according to one of claims 1 to 10 characterized by the following method steps: - Provision of a valve seat ring having a valve seat surface and a spaced from the valve seat surface in the axial direction deformation region, according to one of claims 1 and 3 to 10; - Providing an impeller housing made of a light metal material for an exhaust gas turbocharger, with a bypass channel, which at the bypass channel output a receiving molding for the valve seat ring with a radial undercut in a corresponding to the deformation region of the valve seat ring region, according to one of claims 1 or 2; - Inserting and positioning the valve seat ring in the axial direction in the Aufnahmeausformung; - Permanent fixation of the valve seat ring in the receiving formation of the bypass channel output by displacement of material of the valve seat ring in said deformation region in the radial direction in the said corresponding radial undercut of the Aufnahmeausformung.

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