Exhaust-gas turbocharger and method for producing a flow housing of an exhaust-gas turbocharger

Abstract

An exhaust-gas turbocharger (1) having a turbine housing (2) which has a turbine spiral (16); and a compressor housing (3) which has a compressor spiral (17). An internal flow-guiding spiral surface (18 or 19 respectively) of the turbine spiral (16) and/or of the compressor spiral (17) is machined in a material-removing process.

Claims

1. An exhaust-gas turbocharger (1) having a one-piece turbine housing (2) which has a turbine spiral (16) defining an internal flow-guiding spiral surface (18); and a one-piece compressor housing (3) which has a compressor spiral (17) defining an internal flow-guiding spiral surface (19), wherein at least a part of the internal flow-guiding spiral surface (18) of the turbine spiral (16) and/or the internal flow-guiding spiral surface (19) of the compressor spiral (17) is machined in a material-removing process.

2. The exhaust-gas turbocharger as claimed in claim 1, wherein the internal flow-guiding spiral surface (18, 19) is machined in a material-removing process in the final circumferential quarter (20) of the turbine spiral (16) and/or of the compressor spiral (17) in the tongue region (22).

3. The exhaust-gas turbocharger as claimed in claim 1, wherein at least a part of the internal flow-guiding spiral surface (18, 19) of the turbine spiral (16) and/or of the compressor spiral (17) is machined by milling.

4. The exhaust-gas turbocharger as claimed in claim 3, wherein the internal flow-guiding spiral surface (18, 19) of the turbine spiral (16) and/or of the compressor spiral (17) is machined by milling in the final circumferential quarter (20) in the tongue region (22).

5. The exhaust-gas turbocharger as claimed in claim 1, wherein at least a part of the internal flow-guiding spiral surface (18, 19) of the turbine spiral (16) and/or of the compressor spiral (17) is machined by interpolation turning.

6. The exhaust-gas turbocharger as claimed in claim 5, wherein the internal flow-guiding spiral surface (18, 19) is machined by interpolation turning in the final circumferential quarter (20) of the turbine spiral (16) and/or of the compressor spiral (17) in the tongue region (22).

7. The exhaust-gas turbocharger as claimed in claim 1, wherein the cross-sectional width at at least a part of the internal flow-guiding spiral surface (18, 19) of the turbine spiral (16) and/or of the compressor spiral (17) is enlarged no further proceeding from the turbine wheel inlet or diffuser outlet respectively.

8. A method for producing a one-piece flow housing (2; 3) of an exhaust-gas turbocharger (1), having the following method steps: casting the one-piece flow housing (2; 3); and machining at least a part of the internal flow-guiding spiral surface (18, 19) of the one-piece flow housing (2; 3) in a material-removing process.

9. The method as claimed in claim 8, wherein the internal flow-guiding spiral surface (18, 19) is machined in a material-removing process in the final circumferential quarter (20) of the turbine spiral (16) and/or of the compressor spiral (17) in the tongue region (22).

10. The method as claimed in claim 8, wherein the turbine spiral (16) and/or the compressor spiral (17) are, in the final circumferential quarter (20), designed such that the cross-sectional width is enlarged no further proceeding from the turbine wheel inlet or diffuser outlet respectively.

11. The method as claimed in claim 8, wherein lateral connection radii (R.sub.1; R.sub.2) of the tongue (22) are of enlarged form at the end (21) of the tongue.

12. The method as claimed in claim 8, wherein the tongue (22) is at least partially thickened in the final circumferential quarter (20).

13. The method as claimed in claim 8, wherein the milling machining is performed by means of a disk milling cutter.

14. The method as claimed in claim 8, wherein the flow housing is a turbine housing (2) and/or a compressor housing (3).

15. The exhaust-gas turbocharger as claimed in claim 1, wherein the internal flow-guiding spiral surface (18, 19) is machined in a material-removing process in the final circumferential quarter (20) of the turbine spiral (16) and/or of the compressor spiral (17) at the end (21) of the tongue.

16. The exhaust-gas turbocharger as claimed in claim 3, wherein the internal flow-guiding spiral surface (18, 19) of the turbine spiral (16) and/or of the compressor spiral (17) is machined by milling in the final circumferential quarter (20) at the end (21) of the tongue.

17. The exhaust-gas turbocharger as claimed in claim 5, wherein the internal flow-guiding spiral surface (18, 19) is machined by interpolation turning in the final circumferential quarter (20) of the turbine spiral (16) and/or of the compressor spiral (17) at the end (21) of the tongue.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

(1) Further details, advantages and features of the present invention emerge from the following description of exemplary embodiments with reference to the drawing, in which:

(2) FIG. 1 shows a perspective sectional illustration of one possible embodiment of an exhaust-gas turbocharger according to the invention;

(3) FIG. 2 shows one possible embodiment of a flow housing according to the invention of the exhaust-gas turbocharger, said flow housing being a turbine housing in the example illustrated;

(4) FIG. 3 shows a sectional illustration through an embodiment of a turbine housing according to the invention;

(5) FIG. 4 shows a sectional illustration, corresponding to FIG. 3, of a further embodiment of the turbine housing according to the invention; and FIG. 5 shows graphs illustrating tolerance ranges for the tongue spacing without milling (casting) and with milling machining

DETAILED DESCRIPTION OF THE INVENTION

(6) FIG. 1 illustrates an exhaust-gas turbocharger 1 according to the invention which has a turbine housing 2 and a compressor housing 3.

(7) The turbine housing 2 has a turbine spiral 16 which is the flow duct which surrounds a turbine wheel 5 which is arranged in the turbine housing 2.

(8) Correspondingly, the compressor housing 3 has a compressor spiral 17 which is the flow duct which surrounds a compressor wheel 7 of the compressor housing 3.

(9) The turbine spiral 16 has an internal spiral surface 18, and the compressor spiral 17 has an internal spiral surface 19, which according to the invention is subjected, for example, to milling machining As explained in the introduction, it is possible according to the invention for either both spiral surfaces 18 and 19 or in each case only one of said spiral surfaces 18 or 19 to be subjected to milling machining, wherein a milled turbine-side internal flow-guiding spiral surface 18 is preferred.

(10) FIG. 1 shows merely an exemplary embodiment of an exhaust-gas turbocharger 1 which may be designed according to the invention. It is self-evident that, in principle, any other conceivable embodiments of such exhaust-gas turbochargers may conceivably be provided so as to be configured according to the invention. Since the further elements of the exhaust-gas turbocharger 1 that are visible in FIG. 1, and which are denoted by the reference numerals 8 to 15, are not required for the explanation of the principles of the present invention, said elements are merely listed in the following list of reference numerals.

(11) FIG. 2 shows one conceivable embodiment of a turbine housing 2 as a representative of a flow housing of an exhaust-gas turbocharger 1. Also with regard to the embodiment of the turbine housing 2 shown in FIG. 2, it is pointed out that this is merely an exemplary embodiment, and any other design of a turbine housing 2 may likewise have the features according to the invention. Furthermore, it is pointed out that the features that are explained below and visible in FIG. 2 also apply in principle to the compressor housing 3 of the exhaust-gas turbocharger 1.

(12) FIG. 2 illustrates again that the turbine housing 2 has a turbine spiral 16 with an internal flow-guiding spiral surface 18, which leads from a housing inlet 8 to the end 21 of a tongue 22. According to the invention, said internal flow-guiding spiral surface 18 is subjected, for example, to milling machining, wherein in particular the final circumferential quarter 20 to the end 21 of the tongue 22 is subjected to milling machining, because said final circumferential quarter 20 has a particularly crucial influence on the increase in efficiency.

(13) As is also shown in FIG. 2, the tongue 22 may, in the region of the end 21 of the tongue, comprise lateral connection radii R.sub.1 and R.sub.2 which are of enlarged form in relation to standard housings. This yields a reduced risk of cracking

(14) Furthermore, it is possible according to the invention for a thickening 24 of the tongue 22 to be provided in the final circumferential quarter 20 for the material-removing machining, in particular in the case of new constructions.

(15) The resulting tongue spacing Z is also plotted in FIG. 2.

(16) Finally, FIG. 2 shows, by means of the arrow PF, that the path of the milling axis is oriented to the profile of the tongue 22 and the A/R profile thereof.

(17) FIG. 3 shows a cross-sectional area, that can be realized for example by means of milling machining, in the final circumferential quarter of 20 of the spiral 16 and/or 17. The A/R profile over the circumference of the spiral continues to correspond to the conventional construction and is controlled only by means of the engagement of the milling cutter. The milling regions in the case of a new construction of said type are indicated by the six points P.

(18) FIG. 4 shows a turbine housing with material removal regions P in the case of an emergency remedy as explained above.

(19) Finally, FIG. 5 shows graphs illustrating tolerance ranges for the tongue section without milling (casting) and with milling machining

(20) Here, the curve K1 shows the tolerance range with milling machining, wherein the tongue spacing is reduced.

(21) The curve K2 shows the tolerance range in the case of milling machining without a reduced tongue spacing, and the curve K3 shows the tolerance range without machining (for example in the case of the casting position tolerances in the case of steel casting). It must also be pointed out that the term HCF configuration is to be understood to mean a configuration which places the emphasis on a high one-time load, that is to say does not focus on load alternation. The abbreviation HCF refers here to High Cycle Fatigue.

(22) The expression A/R profile is to be understood to mean an area profile of a spiral which is characterized as a dimensionless ratio of cross-sectional area at a certain circumferential point and the associated centroid radius.

(23) In addition to the above written description of the invention, reference is hereby explicitly made, for additional disclosure thereof, to the diagrammatic illustration of the invention in FIGS. 1 to 5.

LIST OF REFERENCE SIGNS

(24) 1 Exhaust-gas turbocharger 2 Turbine housing 3 Compressor housing 4 Bearing housing 5 Turbine wheel 6 Shaft 7 Compressor wheel 8 Turbine housing inlet 9 Turbine housing outlet 10 Flap arrangement 11 Flap plate 12 Flap lever/spindle 13 Flap shaft 14 Control rod 15 Actuator 16 Turbine spiral 17 Compressor spiral 18 Internal spiral surface of the turbine housing 2 19 Internal spiral surface of the compressor housing 3 20 Final circumferential quarter 21 End of the tongue 22 Tongue 23 Region of the rectangular shape in the final circumferential quarter 20 24 Thickening