TURBINE HOUSING FOR TURBOCHARGER

Abstract: A turbocharger turbine housing (1) includes two segments (1a,1b) which engage in an abutment plane (6) perpendicular to the turbine axis and together define a first groove (7) extending around the inner surface of the housing. A partition plate (8) whose outer edge is slidably received in the first groove (7) and defines a clearance (c) with the base of the groove divides the turbine gas passage (3) into two gas paths (3a,3b). The segments (1a,1b) define an inlet opening to the gas passage and a partition plate receiving member (12) is received in the inlet opening and includes an elongate portion extending across the inlet opening in the abutment plane. The elongate portion has a first major surface directed towards the turbine gas passage (3) and an opposed second major surface. The first major surface defines a second groove (13) which slidably receives an edge of the partition plate which together with the base of the second groove (13) defines a clearance (c). The second major surface is coplanar with the outer surfaces of the segments which define the inlet opening. Spaces (12b) are defined between the partition plate receiving member (12) and the housing adjacent the ends of the elongate portion whereby thermal expansion of the elongate portion may be accommodated without cracks tending to be formed in the housing.

Description: The present invention relates to a turbine housing for a turbocharger in which a gas passage is defined in a turbine wheel chamber to introduce gas to a turbine wheel and more particularly a turbine housing for a turbocharger in which a gas passage is divided into a plurality of gas paths axially of the turbine. It is common in turbocharger technology to divide the gas passage within a turbine housing into a plurality of gas paths so as to utilise the dynamic energy of the flowing gas to improve the turbocharger performance. In some turbochargers of this type, a partition plate or plates which separate the gas passage into a plurality of gas paths are formed integrally with the turbine housing. Figures 1 and 2 are a sectional elevation and a scrap radial sectional view on an enlarged scale on the line II-II in Figure 1, respectively of such a known turbocharger housing. As may be seen the volute or scroll-shaped inner surface of the turbine housing 1 has a partition plate 2 integral with it which divides the gas passage 3 into two gas paths 3a and 3b axially of the turbine wheel 4. Such turbochargers with an integral turbine housing 1 and partition plate 2 have the disadvantage that the inner periphery of the partition plate 2 tends to crack as shown in Figure 1, under the thermal effect exerted on it by the turbine wheel. This is because thermal deformation of the partition plate 2 is constrained by the fact that it is integral with the turbine housing and thermal stresses tend to be concentrated in the partition plate 2. In order to solve this problem a construction has been proposed in which the turbine housing is divided into segments and a partition plate independent of the turbine housing is fitted between the segments. The independent partition plate is not subject to cracking when subjected to high temperatures since it can thermally deform in the radial and circumferential directions. However, circumferential deformation of the partition plate may cause the end face of the partition plate at the gas inlet 1′ of the turbine housing to be displaced with the disadvantageous result that the gases which are intended to flow through their respective gas paths may be mixed. EP 0204509 A1 discloses a turbine housing for a turbocharger which seeks to overcome the disadvantage of the gas flows mixing at the gas inlet. In this construction a partition wall supporting member, which is integral with or welded to the housing, extends across the gas inlet. The partition wall supporting member defines a groove which slidably receives the edge of the partition plate and permits the latter to move under the influence of changing temperatures without the two gas paths coming into communication. By virtue of the fact that the ends of the partition plate supporting member are integral with or welded to the turbine housing, differential expansion of the partition plate supporting member can not readily be accommodated and tends to lead to rupture or cracking of the turbine housing. It is therefore an object of the present invention to provide a turbine housing for a turbocharger in which a partition plate receiving member is provided in an opening defined by the housing to avoid mixing of the gas flows and which is so constructed that a concentration of thermal stresses does not occur and the housing is not liable to cracking by reason of differential expansion of the partition plate receiving member. According to the present invention there is provided a turbine housing for a turbocharger, the housing including two segments which engage in an abutment plane extending substantially perpendicular to the turbine axis and together define a first groove extending around the inner surface of the housing, a partition plate which divides the turbine gas passage into two gas paths and whose outer edge is received in the first groove and defines a clearance with the base of the groove, the segments defining at least one opening which communicates with the turbine gas passage, a partition plate receiving member being received in the said opening and including an elongate portion extending across it substantially in the abutment plane, the said elongate portion having a first major surface directed towards the turbine gas passage and an opposed second major surface, the first major surface defining a second groove which receives an edge of the partition plate which together with the base of the second groove defines a clearance, the second major surface being substantially coplanar with the outer surfaces of the segments which define the said opening, the partition plate receiving member being received in one or more recesses in the periphery of the opening, which communicate with the opening, characterised in that the partition plate receiving member is connected to the segments in a gas tight manner and that spaces are defined between the partition plate receiving member and the segments adjacent the ends of the said elongate portion whereby thermal expansion of the said elongate portion may be accommodated. Thus in accordance with the present invention an expansion space is provided between the partition plate receiving member and the edge of the outlet opening in line with the ends of the elongate portion of the partition plate receiving member, which expansion space permits differential expansion of the elongate portion to be accommodated without tending to crack the turbine housing. The segments are preferably provided with a flange which extends around the said opening, the flange defining one or more recesses which communicate with the said opening and receive the partition plate receiving member which is connected to the segments in a gas-tight manner. In one embodiment the partition receiving member has a lug or extension at each end and is of generally I-shape, the spaces being defined between the lugs and the edge of the opening. In the alternative embodiment the partition plate receiving member comprises an annular portion traversed by the said elongate portion, the spaces being defined between the annular portion and the edge of the opening. The opening may be either the gas inlet opening to the housing or a waste gate outlet opening and it will be appreciated that in fact both types of opening may be provided, both of which are provided with a partition plate receiving member of the type referred to above. The invention also embraces a turbocharger including such a turbine housing. Further features, details and advantages of the present invention will be apparent from the following description of two preferred embodiments which is given with reference to Figures 3 to 8 of the accompanying drawings, in which: Figure 3 is a cross-sectional view of a first preferred embodiment of the present invention; Figure 4 is a sectional view, on an enlarged scale, on the line IV-IV in Figure 3; Figure 5 is an end view, on an enlarged scale, on the line V-V in Figure 3; Figure 6 is a sectional view, on an enlarged scale, on the line VI-VI in Figure 5; Figure 7 is a scrap sectional view of a second preferred embodiment of the present invention; Figure 8 is a scrap end view of the partition plate mounting in the embodiment of Figure 7; and Figures 9 and 10 are diagrammatic perspective views of the partition plate receiving member of Figures 7 and 8 and Figures 3 to 6, respectively. The turbine housing 1 shown in Figures 3 to 6 is divided into two housing segments 1a and 1b axially of the housing 1. The abutting portions of the segments 1a and 1b abut along a plane 6 and define a groove 7 which extends from the gas inlet around the entire inner surface of the scroll or turbine housing. A generally annular partition plate 8 which is independent of the turbine housing 1 divides the gas passage 3 into two separate gas paths 3a and 3b. The outer periphery of the annular partition plate 8 is snugly received in the groove 7 such that a clearance c is defined between the outer periphery of the plate 8 and the base of the groove 7. The abutting peripheries of the segments 1a and 1b are securely connected by welding or the like so that the gas paths 3a and 3b, which communicate with the turbine wheel chamber 9 are completely axially separated. The segments 1a and 1b are flanged at 10 at the opening of the inlet passage for connection to a gas supply pipe and define the gas inlet through which gases are supplied via the gas paths 3a and 3b to the turbine wheel chamber 9 which accommodates a turbine wheel 4. The flanges 10 have recesses on their inner periphery and together define arcuate receiving portions 11 which are diametrically opposed and extend across the abutment plane 6 and receive a respective end of a partition plate receiving member 12. The receiving member 12 has a length sufficient to extend across the gas passage at the gas inlet and has horizontal extensions or lugs 12a at its ends thereof. The receiving member 12 has further a second groove 13 which is formed at its inner or first major surface. The extensions 12a of the receiving member 12 are drive-fitted in an air-tight manner into the receiving portions 11 or securely connected thereto by welding so that the receiving member 12 can not fall out of the flanges 10. The end of the partition plate 8 at the gas inlet, which moves as a result of thermal expansion, is slidably received in the groove 13 on the receiving member 12 and a clearance c is defined between the end face of the partition plate 8 and the base of the groove 13. The partition plate receiving member 12 is embedded or received in the recesses 11 such that the outer or opposed second major surface of the receiving member 12 is coplanar with the outer surface of the flanges 10. Even when the end face of the partition plate 8 at the gas inlet moves it is still accommodated within the groove 13 and thus mixing of the gases flowing through the gas paths 3a and 3b is prevented. The performance of the partition plate 8 is thus ensured. During operation of the turbine, the partition plate 8 is acted on by thermal loads and tends to be thermally deformed. Since the partition plate 8 is independent of the turbine housing 1, thermal deformation in the radial and circumferntial directions within the groove 7 are permitted. As a result, a concentration of thermal stresses is avoided and no cracks are produced in the partition plate 8. Thermal deformation of the partition plate 8 in the circumferential direction and thus movement of the end face of the partition plate 8 at the gas inlet of the turbine housing 1 can be accommodated since the partition plate 8 is slidably received in the groove 13 on the receiving member 12 and can move within the clearance c in the groove 13. In operation of the turbine, the partition plate receiving member 12 is also subjected to high temperatures and tends to be thermally deformed. Thermal deformation of the receiving member 12 in its longitudinal direction can be absorbed since the receiving member 12 has the extensions 12a which together with the side wall of the inlet passage define notches or spaces 12b over at least a major proportion of their length which permit thermal deformation. If the receiving member 12 had no extensions at its ends thereof and were drive-fitted into, or connected by welding to, the flange surface, stresses would be concentrated at the abutment 6 between the segments 1a and 1b due to thermal deformation of the partition plate receiving member 12 and cracks would tend to be produced. According to the present invention, the partition plate receiving member 12 can absorb thermal deformations, as described above, so that even when the partition plate receiving member 12 is thermally deformed, cracking at the abutment 6 between the housing segments 1a and 1b is prevented. The partition plate receiving member 12 has been described as being disposed at the gas inlet to the turbine wheel chamber, but it is to be understood that a partition plate receiving member 12 may also be disposed, as shown in Figure 7, at a waste gate outlet where the partition plate 8 is movable so that a mixing of the gases flowing through the gas paths can be prevented and the performance of the partition plate 8 can be ensured. The partition plate receiving member 12 is disposed at the waste gate outlet 14 in a manner which will be described below with reference to Figure 8. The receiving member 12 comprises an annular portion 15 whose shape corresponds to that of the gas outlet 14 and which is traversed by a diametrical portion which affords a partition plate receiving groove 16 which slidably receives the partition plate 8 which divides the gas passage into gas paths 3a and 3b. These gas paths communicate via substantially semi-circular openings 3a′ and 3b′ with the exterior. The annular portion 15 is drive-fitted into a circular recess at the surface of the waste gate outlet and has two diametrically opposed flats adjacent the ends of the diametrical portion which together with the edge of the recess define notches or spaces 17 which serve to absorb thermal deformations. As an alternative to drive or force fitting the receiving member 12 in the circular recess it may be welded to the waste gate outlet at diametrically opposed notches 18 on the receiving member 12 which are offset from the spaces 17 by 90° so that the receiving member 12 can not fall off. The partition plate receiving member 12 of the type described above permits thermal deformation of the partition plate 8 so that the latter is supported at the waste gate outlet 14 with no stress concentration, whereby the performance of the partition plate 8 is ensured and mixing of the gas flows is reliably prevented.

Claims: 1. A turbine housing (1) for a turbocharger, the housing including two segments (1a, 1b) which engage in an abutment plane (6) extending substantially perpendicular to the turbine axis and together define a first groove (7) extending around the inner surface of the housing, a partition plate (8) which divides the turbine gas passage (3) into two gas paths (3a, 3b) and whose outer edge is received in the first groove (7) and defines a clearance (c) with the base of the groove, the segments (1a, 1b) defining at least one opening which communicates with the turbine gas passage, a partition plate receiving member (12) being received in the said opening and including an elongate portion extending across it substantially in the abutment plane (6), the said elongate portion having a first major surface directed towards the turbine gas passage (3) and an opposed second major surface, the first major surface defining a second groove (13) which receives an edge of the partition plate (8) which together with the base of the second groove (13) defines a clearance (c), the second major surface being substantially coplanar with the outer surfaces of the segments (1a, 1b) which define the said opening, the partition plate receiving member (12) being received in one or more recesses in the periphery of the opening, which communicate with the opening, characterised in that the partition plate receiving member (12) is connected to the segments (1a, 1b) in a gas tight manner and that spaces (12b; 17) are defined between the partition plate receiving member (12) and the segments (1a, 1b) adjacent the ends of the said elongate portion whereby thermal expansion of the said elongate portion may be accommodated. 2. A housing as claimed in claim 1 characterised in that each space (12b; 17) is defined by an arcuate surface of the said opening and a flat surface of the partition plate receiving member. 3. A housing as claimed in claim 1 or claim 2 characterised in that the segments (1a, 1b) are provided with a flange (10) which extends around the said opening, the flange defining the said one or more recesses. 4. A housing as claimed in any one of claims 1 to 3 characterised in that the partition plate receiving member (12) has a lug or extension (12a) at each end and is of generally I-shape, the spaces (12b) being defined between lugs (12a) and the edge of the opening. 5. A housing as claimed in any one of claims 1 to 3, characterised in that the partition plate receiving member (12) comprises an annular portion traversed by the said elongate portion, the spaces (17) being defined between the annular portion and the edge of the opening. 6. A housing as claimed in any one of the preceding claims characterised in that the said opening is the gas inlet opening to the housing. 7. A housing as claimed in any one of the preceding claims characterised in that the said opening is a waste gate outlet opening. 8. A housing as claimed in claim 7 characterised in that there are two openings, one of which is the gas inlet opening to the housing and the other of which is a waste gas outlet opening. 9. A turbocharger characterised by a turbine housing as claimed in any one of the preceding claims.

Inventors: KONDO, NOBUHIRO, TAKAGI, KINSHI
Applicants: ISHIKAWAJIMA-HARIMA  JUKOGYO KABUSHIKI KAISHA
Application year: 1987
Main classification: F01D9
IPC codes: F01D9, F02B39, F01D25