JP2015183561A - turbine housing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To successfully join and fix an inside housing and an outside housing to each other, in a turbine housing having double-pipe structure.SOLUTION: A turbine housing 10 comprises an inside housing 12 and an outside housing 14. The inside housing 12 is made of a cast, is formed integrally and seamlessly by casting and comprises: a scroll part 21 which constitutes a spiral exhaust gas flow passage; and an outlet pipe part 22 which is a substantially tubular portion and is provided in a protruding condition along a turbine rotation center axial line C from the scroll part 21, and constitutes an outlet of an exhaust gas. The outside housing 14 is formed from a sheet metal and provided so as to cover the scroll part 21. The outside housing 14 abuts on a surface 25 at a side opposite to a side at which the outlet pipe part 22 is provided, of the inside housing 12, abutment parts between the outside housing 14 and the inside housing 12 are formed into a substantially-annular shape with the turbine rotation center axial line C as a center, and the abutment parts are welded together at a plurality of divided points S 11 ... with respect to a circumferential direction with the turbine rotation center axial line C as a center.

Description

  The present invention relates to a turbine housing of a turbocharger.

  As a conventional turbine housing, one having a so-called double pipe structure is known (for example, see Japanese Patent Application Laid-Open No. 2007-2791). According to such a structure, heat absorption in the turbine housing is suppressed, so that the exhaust gas is discharged from the turbine housing while being maintained at a high temperature, thereby enabling early activation of the catalyst at the cold start of the internal combustion engine. It is done.

JP 2007-2791 A

  In such a double-pipe turbine housing, the inner housing is required to have high heat resistance and shape accuracy. For this reason, it is preferable to use a cast product (cast iron, cast steel, etc .: a relatively expensive austenitic material) as the inner housing. On the other hand, the outer housing is preferably made of a sheet metal (particularly a relatively inexpensive ferritic stainless steel sheet) from the viewpoint of mountability and cost. Thereby, good productivity and good catalyst warm-up performance are compatible.

  However, in the configuration as described above, a difference in thermal expansion occurs between the inner housing that is in direct contact with the exhaust gas and the outer housing that covers the inner housing from the outside. In particular, as described above, when the material is different between the inner housing and the outer housing, the difference in the amount of thermal expansion as described above becomes noticeable due to the difference in the thermal expansion coefficient associated therewith. For this reason, in the turbine housing of a double pipe structure, it becomes a subject to join and fix an inner housing and an outer housing satisfactorily. The present invention has been made in view of the circumstances exemplified above.

  In order to cope with the above-described problem, the invention described in claim 1 is described as follows: “A scroll portion constituting a spiral exhaust gas flow path, and a substantially circular tube projecting from the scroll portion along the turbine rotation center axis. And an outlet pipe portion that constitutes an exhaust gas outlet, and is integrally formed by casting seamlessly and integrally, and is formed of a sheet metal, and the scroll portion is An outer housing provided so as to cover, the outer housing being in contact with a surface of the inner housing opposite to the side on which the outlet pipe portion is provided, the outer housing, the inner housing, The abutting portion is formed in a substantially annular shape around the turbine rotation center axis, and the abutting portion is divided in a circumferential direction around the turbine rotation center axis. It is characterized in that it is welded at several plants.

  In the turbine housing according to the first aspect, the contact portion between the inner housing and the outer housing is formed in a substantially annular shape. Such abutting portions are welded at a plurality of divided locations in the circumferential direction. That is, in the contact portion, the welded portion and the non-welded portion are alternately formed in the circumferential direction.

  According to such a configuration, even if a temperature difference occurs between the inner housing that is in direct contact with the exhaust gas and the outer housing that covers the inner housing from the outside, the above-described non-welded portion is provided, so that thermal expansion is achieved. The stress caused by the difference in amount is relieved well. Therefore, according to the present invention, the inner housing and the outer housing can be satisfactorily joined and fixed.

  According to a second aspect of the present invention, in the first aspect of the invention, the inner housing is a wall portion of the scroll portion provided on the center housing side, and is a plane having the turbine rotation center axis as a normal line. An inner annular wall portion having a substantially annular surface parallel to the inner annular wall portion, and a fitting tube which is a substantially circular tubular portion protruding from the inner annular wall portion toward the center housing along the turbine rotation center axis And the outer housing includes an outer annular wall portion that is a substantially annular wall portion joined to the inner annular wall portion, and the outer annular wall portion along the turbine rotation center axis. A flange-supporting tube portion that is formed in a substantially circular tubular shape protruding on the center housing side so that the fitting tube portion is fitted inside, and protrudes outward from the flange support tube portion. Established The center housing and includes a bondable-formed flange portion, and the outer annular wall and the flange support tube portion and the flange portion is characterized in that it is formed integrally without seam Te.

  In the turbine housing according to claim 2, the inner annular wall portion in the inner housing and the outer annular wall portion in the outer housing are in contact with each other, and the fitting tube portion in the inner housing is inside the flange supporting tube portion in the outer housing. Mated. In this state, the substantially annular contact portion between the inner annular wall portion and the outer annular wall portion is welded at a plurality of locations divided in the circumferential direction. Further, the flange portion in the outer housing is joined to the center housing.

  According to such a configuration, the joining and fixing of the inner housing and the outer housing, and the connection between the turbine housing and the center housing are favorably performed with a simple structure.

1 is a cross-sectional view illustrating a schematic configuration of a turbine housing according to an embodiment of the present invention. Sectional drawing which expanded a part of FIG. FIG. 2 is an external view of the turbine housing illustrated in FIG. 1. The external view which shows the structure of the turbine housing which concerns on one modification.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, an embodiment of the invention will be described with reference to the drawings. In addition, since a modification will prevent understanding of description of one consistent embodiment, if it is inserted during the description of the said embodiment, it is described collectively at the end.

<Configuration>
With reference to FIGS. 1 to 3, the turbine housing 10 of the present embodiment includes an inner housing 12 and an outer housing 14. The inner housing 12 is made of austenitic cast iron or cast steel having high heat resistance, and is integrally formed by casting. The outer housing 14 is provided so as to cover the inner housing 12 from the outside.

  The turbine housing 10 is hermetically connected to a center housing 16 (see FIG. 2) that rotatably supports a turbine wheel (not shown). Specifically, the turbine housing 10 is joined to a center flange 17 provided in the center housing 16 and is joined by a fastener 18 that is a so-called “V band”.

  The inner housing 12 made of a casting has a scroll part 21, an outlet pipe part 22, an inner annular wall part 23, and a fitting pipe part 24. The scroll part 21 is formed in a substantially annular shape (ring) so as to constitute a spiral exhaust gas flow path. The outlet pipe portion 22 is a substantially circular tubular portion that constitutes an exhaust gas outlet in the inner housing 12, and extends from the scroll portion 21 in the axial direction (a direction parallel to the turbine rotation center axis C) along the center housing 16. It protrudes toward the opposite side. Here, the “turbine rotation center axis C” is a straight line passing through the spiral center of the scroll portion 21 and is provided coaxially with the rotation center axis of the turbine wheel (not shown).

  The inner annular wall portion 23 is a wall portion of the scroll portion 21 provided on the center housing 16 side, and is formed in a substantially flat plate shape (disk shape) perpendicular to the turbine rotation center axis C. The fitting tube portion 24 is a substantially circular tubular portion, and projects from the inner edge portion of the inner annular wall portion 23 toward the center housing 16 side along the axial direction. Around the fitting tube portion 24, an annular surface 25, which is a surface of a substantially annular inner annular wall portion 23, parallel to a plane whose normal is the turbine rotation center axis C, is provided.

  The outer housing 14 is provided so as to cover almost the entire inner housing 12 including the scroll portion 21 from the outside. In the present embodiment, the outer housing 14 has a first cover 41 and a second cover 42. That is, in the present embodiment, the outer housing 14 is divided into the first cover 41 and the second cover 42 at positions corresponding to the inner housing 12 in the axial direction. An inlet flange 43 is provided on the outer housing 14 on the inlet side of the exhaust gas in the turbine housing 10.

  The main body portion of the first cover 41 and the portion constituting the downstream side in the exhaust gas flow direction from the inlet flange 43 includes an outer annular wall portion 411, an inner tube covering portion 412, and a flange support tube portion 413. And a flange portion 414. The first cover 41 having such a configuration is integrally formed by seamlessly performing a process such as bending on a relatively inexpensive ferritic stainless steel sheet metal. The second cover 42 is also formed of a sheet metal made of ferritic stainless steel.

  The outer annular wall portion 411 is a substantially annular wall portion in the first cover 41, and is disposed in parallel with the inner annular wall portion 23 so as to be joined to the inner annular wall portion 23. Specifically, the outer annular wall portion 411 has a substantially flat plate shape (disc shape) perpendicular to the turbine rotation center axis C, and has an outer diameter larger than that of the inner annular wall portion 23.

  The inner pipe covering portion 412 is provided outside the inner housing 12 constituting the inner pipe in the turbine housing 10 having a double pipe structure so as to cover the inner housing 12 with a gap therebetween. Specifically, the inner tube covering portion 412 is bent along the annular outer surface of the scroll portion 21 while extending outward from the outer edge portion of the outer annular wall portion 411.

  The flange support tube portion 413 is a substantially circular tubular portion protruding from the inner edge of the outer annular wall portion 411 along the axial direction toward the center housing 16, and the fitting tube portion 24 is fitted inside the flange support tube portion 413. It is formed to be. The flange portion 414 is provided so as to gradually increase in diameter from the distal end portion of the flange support pipe portion 413 toward the outside, and is formed so as to be connectable to the center flange 17.

  Thus, the first cover 41 in the outer housing 14 is in contact with the annular surface 25 (the surface opposite to the side on which the outlet pipe portion 22 is provided) in the inner housing 12. That is, the contact portion S between the inner annular wall portion 23 (annular surface 25) in the inner housing 12 and the outer annular wall portion 411 in the first cover 41 is formed in a substantially annular shape around the turbine rotation center axis C. Yes.

  The contact portion S (see FIGS. 1 and 2) is provided with a plurality of welded portions S11, S12... And a plurality of non-welded portions S20 (see FIG. 3). The welded portion S11 or the like is a portion where the inner annular wall portion 23 in the inner housing 12 and the outer annular wall portion 411 in the first cover 41 are welded by a well-known welding method (for example, spot welding). On the other hand, the non-welded portion S20 is a portion where the inner annular wall portion 23 in the inner housing 12 and the outer annular wall portion 411 in the first cover 41 are not welded. In the contact portion S, the welded portions S11 and the like and the non-welded portions S20 are alternately arranged along the circumferential direction around the turbine rotation center axis C. That is, the inner annular wall portion 23 in the inner housing 12 and the outer annular wall portion 411 in the first cover 41 (outer housing 14) are divided into a plurality of locations in the circumferential direction around the turbine rotation center axis C. Are welded.

  More specifically, in the present embodiment, the contact portion S is provided with welded portions S11, S12, and S13 and a non-welded portion S20. The welded portion S11 is formed in a short arc shape with the position P in FIG. 3 as a midpoint (specifically, the center angle is about 40 degrees with respect to the point C in FIG. 3). Here, the position P described above includes the turbine rotation center axis C with the gas inflow line GL (a straight line passing through the center at the exhaust gas inlet formed at the inlet flange 43 and parallel to the exhaust gas inflow direction G) as a normal line. This is a position where the flat surface and the abutting portion S intersect with each other, and is a position where the abutting portion S reaches the highest temperature due to the inflow of exhaust gas. The welded portions S12 and S13 are formed with substantially the same length as the welded portion S11 in the circumferential direction described above. Moreover, welding part S11, S12, and S13 are arrange | positioned at equal intervals about the above-mentioned circumferential direction.

<Action and effect>
Hereinafter, functions and effects obtained by the configuration of the present embodiment will be described.

  When the high-temperature exhaust gas flows through the turbine housing 10, thermal expansion occurs in the inner housing 12 and the outer housing 14 (particularly, the first cover 41). Such thermal expansion occurs in a radial direction (up and down direction in FIG. 1) around the turbine rotation center axis C and the above-described circumferential direction (see arrows in FIG. 3).

  Here, there is a temperature difference between the inner housing 12 that is in direct contact with the exhaust gas and the first cover 41 that is a member that covers the inner housing 12 from the outside and that does not normally contact the exhaust gas. Occurs. In particular, since the inner housing 12 is a cast product and an austenitic material, and the first cover 41 is made of sheet metal and a ferrite material, the difference in thermal expansion between the two is remarkable with the difference in thermal expansion coefficient. Become.

  In this respect, in the configuration of the present embodiment, a portion where the inner annular wall portion 23 in the inner housing 12 and the outer annular wall portion 411 in the first cover 41 are not restrained is generated in the non-welded portion S20. Thereby, the stress resulting from the difference in the amount of thermal expansion is relieved satisfactorily. Therefore, according to this structure, it becomes possible to join and fix the inner housing 12 and the outer housing 14 (first cover 41) satisfactorily.

  In the configuration of the present embodiment, the center housing 16 and the outer housing 14 are hermetically connected by being fastened by the fastener 18 while the center flange 17 and the flange portion 414 of the outer housing 14 are joined. ing. For this reason, even if the non-welded portion S20 as described above is provided, there is no concern that exhaust gas leaks outside through the non-welded portion S20.

  Further, in the configuration of the present embodiment, the flange portion 414 for forming a connection with the center housing 16 is normally a part of the first cover 41 (outer housing 14) that does not directly contact exhaust gas. The first cover 41 is formed integrally with the rest of the first cover 41. For this reason, the degree of temperature rise due to the flow of exhaust gas in the flange portion 414 is lower than that of the inner housing 12. Further, inadvertent temperature rise of the center housing 16 and inadvertent cooling of the turbine housing 10 due to heat transfer between the hot inner housing 12 and the cooled center housing 16 are satisfactorily suppressed. Therefore, according to the present embodiment, the joining and fixing of the inner housing 12 and the outer housing 14 and the connection between the turbine housing 10 and the center housing 16 are favorably performed with a simple structure.

<Modification>
Hereinafter, some typical modifications will be exemplified. In the following description of the modified examples, the same reference numerals as those in the above embodiment can be used for portions having the same configurations and functions as those described in the above embodiment. And about description of this part, the description in the above-mentioned embodiment shall be used suitably in the range which is not technically consistent. Needless to say, the modifications are not limited to those listed below. In addition, a part of the above-described embodiment and all or a part of the plurality of modified examples can be combined appropriately as long as they are technically consistent.

  The present invention is not limited to the specific apparatus configuration (including structure and material) described above. That is, for example, the division structure of the outer housing 14 is not limited to the above specific example. Further, as a material constituting the outer housing 14, a sheet metal made of austenitic stainless steel (for example, SUS304 material or the like: SUS302 material having excellent heat resistance, SUS309S, SUS310S, or the like) may be used. Accordingly, it is possible to impart high heat resistance and shape accuracy to the inner housing 12 while suppressing as much as possible a difference in thermal expansion between the inner housing 12 and the outer housing 14.

  A flange portion for forming a connection with the center housing 16 may be provided in the fitting tube portion 24 in the inner housing 12. Further, the joining / fixing structure between the turbine housing 10 and the center housing 16 can be appropriately changed from the above-described specific example.

  The welded portions S11 and the like may be provided at two or more locations (typically three or more locations: for example, 3 to 5 locations). For example, as shown in FIG. 4, four welded portions (welded portions S11, S12, S13, and S14) may be provided. In the configuration of the modified example shown in FIG. 4, the welds S11, S12, S13, and S14 are arranged at equal intervals in the circumferential direction described above. Note that there is no particular limitation on the welding method, position, and length and interval in the circumferential direction (including whether the intervals are equal or unequal) in the welded portion S11 or the like.

  Other modifications not specifically mentioned are naturally included in the technical scope of the present invention without departing from the essential part of the present invention. In addition, in each element constituting the means for solving the problems of the present invention, elements expressed in terms of function and function are specific configurations disclosed in the above-described embodiments and modifications, and equivalents thereof. In addition to objects, any configuration capable of realizing the action / function is included.

  DESCRIPTION OF SYMBOLS 10 ... Turbine housing, 12 ... Inner housing, 14 ... Outer housing, 16 ... Center housing, 21 ... Scroll part, 23 ... Inner annular wall part, 24 ... Fitting pipe part, 25 ... Annular surface, 41 ... First cover, 42 ... second cover, 411 ... outer annular wall portion, 413 ... flange support tube portion, 414 ... flange portion, C ... turbine rotation center axis, S ... contact portion, S11, S12, S13, S14 ... welded portion, S20 ... non-welded part.

Claims (2)

A scroll portion constituting a spiral exhaust gas flow path, and a substantially tubular portion protruding from the scroll portion along the turbine rotation center axis, and an outlet pipe portion constituting an exhaust gas outlet. An inner housing made of a casting that is seamlessly formed integrally by casting,
An outer housing formed of sheet metal and provided to cover the scroll portion;
With
The outer housing is in contact with a surface of the inner housing opposite to the side where the outlet pipe portion is provided;
The contact portion between the outer housing and the inner housing is formed in a substantially annular shape around the turbine rotation center axis,
The turbine housing according to claim 1, wherein the contact portion is welded at a plurality of divided locations in a circumferential direction around the turbine rotation center axis. The inner housing includes a wall portion of the scroll portion provided on the center housing side, and an inner annular wall portion having a substantially annular surface parallel to a plane whose normal is the turbine rotation center axis. A fitting tube portion that is a substantially circular tubular portion projecting from the inner annular wall portion toward the center housing along the turbine rotation center axis.
The outer housing projects from the outer annular wall portion, which is a substantially annular wall portion joined to the inner annular wall portion, to the center housing side along the turbine rotation center axis. A flange-supporting tube portion formed so as to be fitted inside the fitting tube portion, and projecting outward from the flange-supporting tube portion. The outer annular wall portion, the flange supporting pipe portion, and the flange portion are formed integrally with each other without any joints. Turbine housing.

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