WO2011104596A2

WO2011104596A2 - Turbocharger and wheel housing thereof

Info

Publication number: WO2011104596A2
Application number: PCT/IB2011/000303
Authority: WO
Inventors: Takahiro Sadamitsu; Tatsuo Iida
Original assignee: Toyota Jidosha Kabushiki Kaisha
Priority date: 2010-02-26
Filing date: 2011-02-07
Publication date: 2011-09-01
Also published as: WO2011104596A3; JP2011179370A

Abstract

A turbine housing 11 of a turbocharger has an exhaust passage 80 formed inside a scroll body 30, and includes a neck portion 35, which forms an end of the exhaust passage 80, as part of the scroll body 30. A reinforcement body 50 formed separately from the scroll body 30 is provided on the inside of the neck portion 35.

Description

TURBOCHARGER AND WHEEL HOUSING THEREOF

FIELD OF THE INVENTION

1. Field of the Invention

[0001] The invention relates to a turbocharger and a wheel housing thereof with a gas passage formed inside a housing main body and with a neck portion, which forms an end of the gas passage, included as part of the main body.

BACKGROUND OF THE INVENTION

[0002] A wheel housing is described in Japanese Patent Application Publication

No. 2008-121470 (JP-A-2008-121470).

[0003] In the meantime, a wheel housing including a neck portion, such as the wheel housing disclosed in Japanese Patent Application Publication No. 2008-121470 (JP-A-2008-121470) is low in the strength of the neck portion. Therefore, the neck portion may be deformed as a result of, for example, vibrations of an internal combustion engine or the like.

SUMMARY OF THE INVENTION

[0004] The invention provides a turbocharger and a wheel housing thereof that can restrain a neck portion from being greatly deformed.

[0005] A first aspect of the invention relates to a wheel housing of a turbocharger. This wheel housing has a gas passage formed inside a housing main body, with a neck portion, which forms an end of the gas passage, included as part of the housing main body. The neck portion is provided, on an inside thereof, with a reinforcement body formed separately from the housing main body.

[0006] In this wheel housing, the neck portion is provided, on the inside thereof, with the reinforcement body formed separately from the housing main body. That is, the neck portion is reinforced from the inside thereof by the reinforcement body. Therefore, the neck portion can be restrained from being greatly deformed.

[0007] In the wheel housing, the reinforcement body may include a joint portion joined to an inner peripheral face of the neck portion, and a rectification portion that rectifies flow of a gas.

[0008] When the flow of exhaust gas flowing into a turbine housing as the wheel housing is inhomogeneous, the exhaust gas suffers a great pressure loss in the gas passage inside the housing. Further, when the flow of intake air flowing out from a compressor housing as the wheel housing is inhomogeneous, the intake air suffers a great pressure loss in an intake passage downstream of the housing. In the aforementioned wheel housing, the reinforcement body is so constructed as to include the rectification portion that rectifies the flow of the gas. Therefore, the flow of the gas flowing into the wheel housing or the flow of the gas flowing out from the wheel housing is rectified, and the pressure loss of the gas can thereby be reduced.

[0009] In the wheel housing, the rectification portion may be in a columnar shape, the joint portion may be in a circular arc shape along an inner periphery of the neck portion on a flow channel cross-section perpendicular to a direction in which the gas flows through the gas passage, and the joint portion may have a chord longer than a width of the rectification portion.

[0010] The reinforcement body may include two circular arc joint portions corresponding to an inner periphery of the neck portion, and a cylindrical rectification portion that connects the two joint portions to each other.

[0011] The reinforcement body may include an annular joint portion joined to the inner peripheral face of the neck portion, and a plurality of rectification portions arranged in a reticular pattern inside the joint portion is joined to the inside of the neck portion.

[0012] In this wheel housing, the reinforcement body is so constructed as to include the columnar rectification portion and the circular arc-like joint portion, and the chord of the joint portion is longer than the width of the rectification portion. Therefore, the area of joint between the neck portion and the joint portion is sufficiently ensured. Accordingly, the joint between the neck portion and the reinforcement body can further be strengthened.

[0013] In the wheel housing, the reinforcement body may be provided as a first reinforcement body and a second reinforcement body, and the neck portion may be provided with the first reinforcement body and the second reinforcement body in such a manner that respective rectification portions of the first reinforcement body and the second reinforcement body intersect with each other when the respective reinforcement bodies are projected onto the flow channel cross-section.

[0014] In this wheel housing, the two reinforcement bodies are provided. Therefore, the effect of rectifying the flow of the gas flowing into the wheel housing or the flow of the gas flowing out from the wheel housing can be made higher than in a case where only one reinforcement body is provided.

[0015] In the wheel housing, the neck portion may be provided with the first reinforcement body and the second reinforcement body in such a manner that the respective rectification portions of the first reinforcement body and the second reinforcement body are perpendicular to each other when the respective reinforcement bodies are projected onto the flow channel cross-section.

[0016] A second aspect of the invention relates to a wheel housing of a turbocharger. This wheel housing has a gas passage formed inside a housing main body, with a neck portion, which forms an end of the gas passage, included as part of the housing main body. The neck portion is provided, on an outside thereof, with a reinforcement body formed separately from the housing main body. The reinforcement body includes a first region joined to an outside of the neck portion, and a second region provided adjacently to the first region in a circumferential direction of the neck portion with a gap between the second region and the neck portion.

[0017] In this wheel housing, the neck portion is provided, on the outside thereof, with the reinforcement body formed separately from the housing main body. That is, the neck portion is reinforced from the outside thereof by the reinforcement body. Therefore, the neck portion can be restrained from being greatly deformed. Further, the reinforcement body is so constructed as to include the region having the gap from the neck portion. Therefore, the degree of heat conduction between the housing main body and the reinforcement body can be reduced.

[0018] In the wheel housing, the neck portion may have a circular cross-sectional contour on a face perpendicular to a direction in which a gas flows through the gas passage, and the reinforcement body may be in a polygonal cross-sectional shape with the outside of the neck portion being an inscribed circle of the polygonal cross-sectional shape, on a plane perpendicular to the direction in which the gas flows through the gas passage.

[0019] A third aspect of the invention relates to a wheel housing of a turbocharger. This wheel housing has a gas passage formed inside a housing main body, with a neck portion, which forms an end of the gas passage, included as part of the housing main body. The neck portion is provided, on an outside thereof, with a flange formed separately from the housing main body and having an exhaust pipe and an intake pipe connected thereto, and a reinforcement body formed separately from the housing main body and located opposite the exhaust pipe or the intake pipe with respect to the flange. The flange and the reinforcement body have a gap formed therebetween.

[0020] In this wheel housing, the neck portion is provided, on the outside thereof, with the reinforcement body formed separately from the housing main body. That is, the neck portion is reinforced from the outside thereof by the reinforcement body. Therefore, the neck portion can be restrained from being greatly deformed. Further, the gap is provided between the flange and the reinforcement body. Therefore, the degree of heat conduction between the flange and the reinforcement body can be reduced.

[0021] In the wheel housing, the reinforcement body may include a first region joined to the outside of the neck portion, and a second region having a gap from the neck portion.

[0022] In the wheel housing, the reinforcement body is so constructed as to include the region joined to the outside of the neck portion and the region having the gap from the neck portion. Therefore, the degree of heat conduction between the housing main body and the reinforcement body can be reduced.

[0023] In the wheel housing, the reinforcement body may include a plurality of the first regions and a plurality of the second regions, and the first regions and the second regions may be alternately provided in a circumferential direction.

[0024] In this wheel housing, the reinforcement body is alternately provided with the first regions and the second regions in the circumferential direction. Therefore, when heat is conducted between the housing main body and the reinforcement body, the distribution of heat in each of the housing main body and the reinforcement body can be restrained from being greatly biased.

[0025] In the wheel housing, the reinforcement body may have a structure equipped with a plurality of mountain-shaped portions each including a region A where the gap formed between the reinforcement body and the neck portion gradually increases toward one side in a circumferential direction, and a region B where the gap formed between the reinforcement body and the neck portion gradually decreases from an end of the region A toward the one side in the circumferential direction, with adjacent ones of the plurality of the mountain-shaped portions, which are arranged in the circumferential direction, joined to each other respectively, and the adjacent ones of the mountain-shaped portions may be joined to each other in a region equivalent to the second region of the reinforcement body.

[0026] In this wheel housing, the reinforcement body having the structure in which the adjacent ones of the plurality of the mountain-shaped portions arranged in the circumferential direction are joined to each other respectively That is, the reinforcement body is continuous in the circumferential direction. Therefore, the troublesomeness in the operation of mounting the reinforcement body on the housing main body can be reduced in comparison with a case where a plurality of discontinuous reinforcement bodies are provided.

[0027] In the wheel housing, the housing main body and the reinforcement body may be joined to each other through brazing.

[0028] In this wheel housing, the housing main body and the reinforcement body are joined to each other through brazing. Therefore, the strains of the housing main body and the reinforcement body resulting from the heat generated during welding can be reduced in comparison with a case where the housing main body and the reinforcement body themselves are fused to each other.

[0029] In the wheel housing, the housing main body may be equipped with a sheet metal scroll body including a scroll-shaped region and the neck portion, and a base body including a flange portion joined to the scroll body, and the gas passage may be formed between the scroll body and the base body.

[0030] In this wheel housing, the scroll body is provided as a sheet metal scroll body. Therefore, the wheel housing can be reduced in weight and thermal capacity. Further, although the strength of the neck portion is lower in strength than in the case of a cast scroll body, the neck portion is reinforced by the reinforcement body and can therefore be restrained from being deformed.

[0031] A turbine housing of the turbocharger may be constructed as the aforementioned wheel housing.

[0032] The turbine housing may include, as the neck portion, an inlet-side neck portion provided on an exhaust gas inlet side and an outlet-side neck portion provided on an exhaust gas outlet side, and the reinforcement body may be provided on the inlet-side neck portion and not on the outlet-side neck portion.

[0033] The inlet-side neck portion constitutes part of the region forming the scroll passage in the turbine housing. That is, the shape of the inlet-side neck portion is more strictly restricted than the shape of the outlet-side neck portion. It is therefore difficult to adopt a structure with high strength. In the aforementioned invention, this inlet-side neck portion is provided with the reinforcement body. Therefore, the inlet-side neck portion can be more reliably restrained from being deformed.

[0034] A compressor housing of the turbocharger may be constructed as the wheel housing.

[0035] The compressor housing may include, as the neck portion, an inlet-side neck portion provided on an intake air inlet side and an outlet-side neck portion provided on an intake air outlet side, and the reinforcement body may be provided on the outlet-side neck portion and not on the inlet-side neck portion.

[0036] The outlet-side neck portion constitutes part of the region forming the scroll passage in the compressor housing. That is, the shape of the outlet-side neck portion is more strictly restricted than the shape of the inlet-side neck portion. It is therefore difficult to adopt a structure with high strength. In the aforementioned invention, this outlet-side neck portion is provided with the reinforcement body. Therefore, the outlet-side neck portion can be more reliably restrained from being deformed.

[0037] A turbocharger may include the wheel housing.

BRIEF DESCRIPTION OF THE DRAWINGS

[0038] The foregoing and further features and advantages of the invention will become apparent from the following description of example embodiments of the invention with reference to the accompanying drawings, wherein like numerals are used to represent like elements and wherein:

FIG. 1 is a schematic view schematically showing a structure of an entire turbocharger as to a first embodiment realized by embodying a turbocharger of the invention;

FIG. 2 is a perspective view showing a perspective structure of a turbine housing according to the first embodiment of the invention;

FIG 3 is a perspective view showing an exploded perspective structure of the turbine housing according to the first embodiment of the invention;

FIG 4 is a cross-sectional view showing a cross-sectional structure of the turbine housing according to the first embodiment of the invention along a line IV- IV of FIG. 2;

FIG. 5 is a cross-sectional view showing a cross-sectional structure of the turbine housing according to the first embodiment of the invention along a line V-V of FIG. 2;

FIG 6 is a cross-sectional view showing a cross-sectional structure of the turbine housing according to the first embodiment of the invention along a line VI-VI of FIG. 5; FIG. 7 is a lateral view showing a lateral structure around a neck portion of a turbine housing as to a second embodiment realized by embodying a turbocharger of the invention;

FIG. 8 is a cross-sectional view showing a cross-sectional structure of the turbine housing according to the second embodiment of the invention along a line VIII- VIII of FIG. 7;

FIG. 9 is a cross-sectional view showing a cross-sectional structure of a B-portion of the turbine housing according to the second embodiment of the invention shown in FIG. 8 on an enlarged scale;

FIG. 10 is a cross-sectional view showing a cross-sectional structure corresponding to the cross-sectional structure of FIG. 6 as to a first modification example of the turbine housing of the invention; and

FIG. 11 is a cross-sectional view showing a cross- sectional structure corresponding to the cross-sectional structure of FIG. 8 as to a second modification example of the turbine housing of the invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0039] (First Embodiment) The first embodiment of the invention will be described with reference to FIGS. 1 to 6. It should be noted that this embodiment of the invention shows an example in which the invention is embodied as a turbine housing of a turbocharger for an internal combustion engine.

[0040] As shown in FIG. 1 , a turbocharger 1 is provided with a turbine wheel 21 that rotates with the aid of the energy of exhaust gas, a compressor wheel 22 that compresses intake air as the wheel 21 rotates, a rotor shaft 23 that connects these wheels to each other, a turbine housing 11 that accommodates the turbine wheel 21, a compressor housing 12 that accommodates the compressor wheel 22, and a center housing 13 that accommodates the rotor shaft 23. An exhaust pipe 91 and an intake pipe 92 are connected to the turbine housing 11 and the compressor housing 12 respectively.

[0041] In the turbocharger 1 , the turbine wheel 21 and the compressor wheel 22 are connected to the rotor shaft 23 respectively. Therefore, these three elements rotate integrally. Further, the turbine housing 11 and the compressor housing 12 are connected to the center housing 13.

[0042] In a turbine housing 11 , an exhaust passage 80 for causing an exhaust gas from an exhaust pipe 91 upstream of the turbine housing 11 to flow to the exhaust pipe 91 downstream of the turbine housing 11 is formed. The exhaust passage 80 is formed of an accommodation chamber 42A in which a turbine wheel 21 is accommodated, a scroll passage 81 that supplies an exhaust gas from the upstream exhaust pipe. 91 to the accommodation chamber 42A, and an outlet passage 82 that delivers an exhaust gas from the turbine wheel 21 to the downstream exhaust pipe 91.

[0043] The structure of the turbine housing 11 will be described with reference to FIGS. 2 to 4. As shown in FIG. 2, the turbine housing 11 includes a scroll body 30 and a base body 40 as a housing main body, an inlet flange 71 to which the exhaust pipe upstream of the turbine housing 11 is connected, and an outlet flange 72 to which the exhaust pipe downstream of the turbine housing 11 is connected. The housing main body is constructed by combining the scroll body 30 equipped with a scroll portion 31 and the base body 40 equipped with a flange portion 43 with each other. A press-molded sheet metal scroll body is employed as the scroll body 30. A cast base body, a cast inlet flange, and a cast outlet flange are employed as the base body 40, the inlet flange 71 , and the outlet flange 72 respectively.

[0044] As shown in FIG. 3, the scroll body 30 includes the disk-shaped scroll portion 31 , and a neck portion 35 forming an inlet of the scroll body 30. The scroll portion 31 is provided with a passage portion 32 composed of a peripheral wall extending in a circumferential direction and a top wall extending in a radial direction to form the scroll passage 81 , a first joint portion 34 joined to a cylinder portion 41 of the base body 40, and a second joint portion 33 joined to the flange portion 43 of the base body 40.

[0045] An inlet flange 71 is joined to the outside of the neck portion 35. Two reinforcement bodies 50 formed separately from the scroll body 30 are joined to the inside of the neck portion 35. Each of the reinforcement bodies 50 includes two circular arc-like joint portions 51 corresponding to an inner periphery of the neck portion 35 of the scroll body 30, and a cylindrical rectification portion 52 that connects these two joint portions 51 to each other.

[0046] The base body 40 is provided with the circular flange portion 43 for connecting a center housing 13 (see FIG. 1) and the turbine housing 11 to each other, the cylinder portion 41 to which the joint portion 33 of the scroll body 30 and an outlet flange 72 are fitted, and an accommodation portion 42 in which the turbine wheel 21 is accommodated. The accommodation portion 42 is provided in such a manner as to connect the cylinder portion 41 and the flange portion 43 to each other. The accommodation portion 42 is provided with a communication passage 42B through which the scroll passage 81 and the accommodation chamber 42A communicate with each other.

[0047] The longitudinal cross-sectional structure of the turbine housing 11 will be described with reference to FIG. 4. It should be noted that FIG. 4 shows a cross-sectional structure of the turbine housing 11 along a line IV-IV of FIG. 2. Further, alternate long and short dash lines P in FIG. 4 indicate centerlines of the turbine housing 11 and the turbine wheel 21. The respective elements of the turbine housing 11 are combined with one another as will be described below.

[0048] The outlet flange 72 is fitted to the outside of a tip end portion 41 C of the cylinder portion 41 of the base body 40. An outer peripheral face 41 A of the tip end portion 41 C and an inner peripheral face 72 A of the outlet flange 72 are joined to each other through brazing.

[0049] The first joint portion 34 of the scroll body 30 is fitted to the outside of a base end portion 41 B of the cylinder portion 41 of the base body 40. The outer peripheral face 41 A of the base end portion 41B and an inner peripheral face 31A of the first joint portion 34 are joined to each other through brazing.

[0050] A top face 42C of the accommodation portion 42 of the base body 40 and the inner peripheral face 31A of the scroll portion 31 of the scroll body 30 are in contact with each other such that there is no gap formed between the top face 42C and the inner peripheral face radially outward of the top face 42C.

[0051] The second joint portion 33 of the scroll body 30 is fitted to the outside of the flange portion 43 of the base body 40. An outer peripheral face 43B of the flange portion 43 and an inner peripheral face 31 A of the second joint portion 33 are joined to each other through brazing.

[0052] A passage for exhaust gas is formed in the turbine housing 11 as will be described below. The scroll passage 81 is formed between the scroll portion 31 on one hand and the accommodation portion 42 and the flange portion 43 on the other hand. Further, an outlet passage 82 is formed in the cylinder portion 41. The scroll passage 81 communicates with an inlet of the accommodation chamber 42A via a communication passage 42B. The outlet passage 82 communicates with an outlet of the accommodation chamber 42A.

[0053] FIG. 5 shows a cross-sectional structure of the turbine housing 11 along a line V-V of FIG. 4. Further, a point P in FIG. 5 indicates centerlines of the turbine housing 11 and the turbine wheel 21. Further, an arrow RA in FIG. 5 indicates a direction of rotation of the turbine wheel 21.

[0054] The inlet flange 71 is fitted to the outside of an inlet-side joint portion 36 of the neck portion 35. An outer peripheral face 36B of the inlet-side joint portion 36 and an inner peripheral face 71 A of the inlet flange 71 are joined to each other through brazing.

[0055] Exhaust gas flows in the turbine housing 11 as will be described below. As indicated by an arrow GA, the exhaust gas in the exhaust pipe 91 upstream of the turbine housing 11 flows into the scroll passage 81 via an opening portion of the neck portion 35. It should be noted that there is turbulence in the flow of the exhaust gas from the exhaust pipe 91. Further, when the exhaust gas in the exhaust pipe 91 flows into the scroll passage 81, there may be formed a swirl swirling in the circumferential direction of the neck portion 35. This swirl does not form the flow of the exhaust gas for rotating the turbine wheel, and hence causes a decrease in supercharging efficiency.

[0056] In the turbine housing 11 , the flow of the exhaust gas that has flowed into the scroll passage 81 is rectified through a rectification action of the reinforcement bodies 50 provided on the neck portion 35. Therefore, the turbulence or swirl of the exhaust gas flowing through the scroll passage 81 is weakened in comparison with a case where the reinforcement bodies 50 are not provided.

[0057] As indicated by an arrow GB, the exhaust gas that has flowed into the inlet of the scroll passage 81 flows through the passage 81 around the accommodation portion 42 in the circumferential direction, and flows into the accommodation chamber 42A via the communication passage 42B in the process.

[0058] As indicated by an arrow GC, the exhaust gas that has flowed into the accommodation chamber 42 A hits a blade of the turbine wheel 21 and is delivered to the outlet passage 82 as the wheel 21 rotates. The exhaust gas that has been delivered to the outlet passage 82 then flows into the exhaust pipe 91 downstream of the turbine housing 11 through the passage 82.

[0059] FIG. 6 shows a cross-sectional structure of the neck portion 35 along a line VI-VI of FIG. 5. The outer peripheral face 5 IB of the joint portion 51 of each of the reinforcement bodies 50 is joined to the inner peripheral face 35A of the neck portion 35. The two joint portions 51 of each of the reinforcement bodies 50 are joined to the neck portion 35, and each of the reinforcement bodies 50 is thereby fixed to the neck portion 35. The rectification portions 52 of the reinforcement bodies 50 are so provided as to pass through a center C of the neck portion 35. The two joint portions 51 of each of the reinforcement bodies 50 are so provided as to face each other across the center C in the radial direction of the neck portion 35.

[0060] The respective reinforcement bodies 50 are joined to the neck portion 35 such that the respective rectification portions 52 intersect with each other and are in contact with each other when the respective reinforcement bodies 50 are projected onto a flow channel cross-section along the radial direction of the neck portion 35. On the flow channel cross-section onto which the respective reinforcement bodies 50 are projected, the scroll passage 81 is divided into four zones by the rectification portions 52 of the respective reinforcement bodies 50. In this case, since the angle formed by one of the rectification portions 52 with the other rectification portion 52 is set to 90°, the aforementioned four zones are identical in size.

[0061] According to this embodiment of the invention, the following effects are achieved. (1) In this embodiment of the invention, the reinforcement bodies 50 formed separately from the scroll body 30 are provided on the inside of the neck portion 35. That is, the neck portion 35 is reinforced from the inside thereof by the reinforcement bodies 50. Therefore, the neck portion 35 can be restrained from being greatly deformed.

[0062] (2) In this embodiment of the invention, the sheet metal scroll body is employed as the scroll body 30. Thus, the scroll body 30 is reduced in thickness in comparison with a case where a cast scroll body is employed. Therefore, the turbocharger 1 can be reduced in weight, and the turbine housing 11 can be reduced in thermal capacity. Further, the neck portion 35 is lower in strength than a cast neck portion due to the reduction in thickness, but since the reinforcement bodies 50 are provided on the neck portion 35, the neck portion 35 can be restrained from being deformed while achieving a reduction in weight and a reduction in thermal capacity as described above.

[0063] (3) When the flow of the exhaust gas flowing into the turbine housing 11 is inhomogeneous, the exhaust gas suffers a great pressure loss in the exhaust passage 80 inside the housing 11. Further, when the exhaust gas in the exhaust pipe 91 flows into the scroll passage 81 , there may be formed a swirl swirling in the circumferential direction on the neck portion 35. In this embodiment of the invention, the rectification portions 52 that rectify the flow of exhaust gas are provided on the inside of the neck portion 53. Therefore, the flow of the exhaust gas flowing into the turbine housing 11 is rectified. Thus, the pressure loss of the exhaust gas can be reduced, and the supercharging efficiency can be restrained from decreasing as a result of a swirl.

[0064] (4) In this embodiment of the invention, the rectification portions 52 assume a columnar shape, and the joint portions 51 assume a circular arc-like shape along the inner periphery of the neck portion 35 on a flow channel cross-section perpendicular to a direction in which the exhaust gas in the exhaust passage 80 flows. Besides, the joint portions 51 have chords longer than the width of the rectification portions 52. Therefore, a sufficient joint area is ensured between the neck portion 35 and each of the joint portions 51. Accordingly, the joint between the neck portion 35 and the reinforcement bodies 50 can further be strengthened.

[0065] (5) In this embodiment of the invention, the neck portion 35 is provided with the two reinforcement bodies 50 in such a manner that the respective rectification portions 52 intersect with each other when the reinforcement bodies 50 are projected onto the flow channel cross-section. Thus, the act of rectifying the flow of the gas flowing into the wheel housing or the flow of the gas flowing out from the wheel housing can be improved in comparison with a case where only one reinforcement body is provided.

[0066] (6) In this embodiment of the invention, the scroll body 30 and each of the reinforcement bodies 50 are joined to each other through brazing. Therefore, the strains of the scroll body 30 and the reinforcement bodies 50 resulting from the heat during welding can be reduced in comparison with a case where the scroll body 30 and each of the reinforcement bodies 50 themselves are fused to each other.

[0067] (7) In this embodiment of the invention, the turbine housing 11 is equipped with the scroll body 30 including the scroll-shaped region and the neck portion 35, and the base body 40 including the flange portion 43 joined to the scroll body 30. The exhaust passage 80 is formed between the scroll body 30 and the base body 40. The sheet metal scroll body is provided as the scroll body 30. Therefore, the turbine housing 11 can be reduced in weight and thermal capacity.

[0068] (8) The turbine housing 11 includes the inlet-side neck portion 35 provided on the exhaust gas inlet side as the neck portion 35, and the cylinder portion 41 as the outlet-side neck portion provided on the exhaust gas outlet side. The inlet-side neck portion 35 forms part of the region forming the scroll passage 81 in the turbine housing 11. That is, the shape of the inlet-side neck portion 35 is more strictly restricted than the shape of the outlet-side cylinder portion 41. It is therefore difficult to adopt a structure with high strength. In this embodiment of the invention, this inlet-side neck portion 35 is provided with the reinforcement bodies 50. Therefore, the inlet-side neck portion 35 can be more reliably restrained from being deformed. Further, only the former of the inlet-side neck portion 35 and the outlet-side neck portion is provided with the reinforcement bodies 50. Therefore, the turbine housing 11 can be reduced in weight in comparison with a case where both the neck portions are provided with the reinforcement bodies 50.

[0069] (Second Embodiment) The second embodiment of the invention will be described with reference to FIGS. 7 to 9. In the foregoing first embodiment of the invention, the reinforcement bodies 50 are joined to the inside of the neck portion 35 of the scroll body 30 to restrain the neck portion 35 from being deformed. On the other hand, in this embodiment of the invention, a reinforcement body 60 is joined to the outside of the neck portion 35 of the scroll body 30 to restrain the neck portion 35 from being deformed. It should be noted that the turbocharger 1 according to this embodiment of the invention adopts a construction common to the first embodiment of the invention except the aforementioned change, and that common components are denoted by the same reference symbols respectively and will not be described below.

[0070] As shown in FIG. 7, the reinforcement body 60 formed separately from the scroll body 30 is provided on an outer peripheral face 35B of the neck portion 35. The reinforcement body 60 is joined to the neck portion 35, with a clearance S formed between the reinforcement body 60 and a lateral face of the inlet flange 71.

[0071] FIG. 8 shows a cross-sectional structure of the neck portion 35 along a line VIII- VIII of FIG. 7. The reinforcement body 60 has a structure in which adjacent ones of a plurality of mountain-shaped portions 61 arranged in the circumferential direction are joined to each other respectively. Joint portions 62 (see FIG. 9) as regions where adjacent ones of the mountain-shaped portions 61 are joined to each other respectively and the vicinities thereof are joined to the neck portion 35 and hence fixed to the outside of the neck portion 35. Thus, the outer peripheral face 35B of the neck portion 35 is entirely surrounded by the reinforcement body 60 in the circumferential direction. Further, there are gaps 64 formed between an inner peripheral face 60A in regions other than the joint portions 62 of the mountain-shaped portions 61 and the outer peripheral face 35B of the neck portion 35.

[0072] FIG. 9 shows an enlarged structure of the mountain-shaped portions 61 (an enlarged structure of a region B of FIG. 8). A first inclined portion 61 A of one of the mountain-shaped portions 61 and a second inclined portion 6 IB of another one of the mountain-shaped portions 61 located opposite that mountain-shaped portion 61 in a direction RA are linked with each other to form a corresponding one of the joint portions 62. Further, a second inclined portion 61 B of one of the mountain-shaped portions 61 and a first inclined portion 61 A of another one of the mountain-shaped portions 61 located on the same side as that mountain-shaped portion 61 in the direction RA are linked with each other to form a corresponding one of the joint portions 62. The inner peripheral face 60A of each of the joint portions 62 and the outer peripheral face 35B of the neck portion 35 are joined to each other through brazing.

[0073] Each of the mountain-shaped portions 61 is composed of the first inclined portions 61 A that distances itself from the neck portion 35 in one circumferential direction RA, and the second inclined portion 61 B that approaches the neck portion 35 in the direction RA from an end of the inclined portion 61 A on the side of the direction RA.

[0074] That is, the first inclined portion 61 A is inclined with respect to the neck portion 35 such that a distance TX between the inner peripheral face 60 A of the first inclined portion 61 A and the outer peripheral face 35B of the neck portion 35 gradually increases in the direction RA. Further, the second inclined portion 61B is inclined with respect to the neck portion 35 such that the distance TX between the inner peripheral face 60A of the second inclined portion 61B and the outer peripheral face 35B of the neck portion 35 gradually decreases in the direction RA.

[0075] Accordingly, the distance TX between the inner peripheral face 60 A of each of the mountain-shaped portions 61 and the outer peripheral face 35B of the neck portion 35 is minimized at a bottom point 61 D in the vicinity of a center of a corresponding one of the joint portions 62, and is maximized at a top point 61 C as a center between two adjacent bottom points 61 D. [0076] According to this embodiment of the invention, the following effects are achieved in addition to the effect (1) of the first embodiment of the invention, namely, the effect of restraining the neck portion from being greatly deformed and the effects (6) to (8) of the first embodiment of the invention.

[0077] (9) In this embodiment of the invention, the reinforcement body 60 formed separately from the scroll body 30 is provided on the outside of the neck portion 35. The reinforcement body 60 includes the joint portions 62 joined to the outside of the neck portion 35, and the regions provided adjacently to the joint portions 62 in the circumferential direction of the neck portion 35 respectively and having the gaps 64 from the neck portion 35. The neck portion 35 is reinforced from the outside thereof by the reinforcement body 60 and hence can be restrained from being greatly deformed. Further, the reinforcement body 60 is so constructed as to include the regions having the gaps 64 from the neck portion 35. Therefore, the degree of heat conduction between the housing main body and the reinforcement body 60 can be reduced. Accordingly, the amount of heat of the exhaust gas that has not hit the turbine wheel 21 yet, namely, the energy for rotating the turbine wheel 21 can be retrained from decreasing. Further, the reinforcement body 60 is alternately provided with the joint portions 62 and the regions having the gaps 64 in the circumferential direction. Therefore, when heat is conducted between the scroll body 30 and the reinforcement body 60, the distribution of heat in each of the scroll body 30 and the reinforcement body 60 can be restrained from being greatly biased. The clearance S is formed between the inlet flange 71 and the reinforcement body 60. Therefore, the degree of heat conduction between the inlet flange 71 and the reinforcement body 60 can be reduced. Further, the reinforcement body 60 is provided on the outside. Therefore, the joining operation can be performed more easily than in a case where the reinforcement body 60 is provided on the inside.

[0078] (10) In this embodiment of the invention, the reinforcement body 60 is equipped with the mountain-shaped portions 61 each including the . first inclined portion 61 A with the gap 64 from the neck portion 35 gradually increasing toward one side in the circumferential direction, and the second inclined portion 61 B with the gap 64 from the neck portion 35 gradually decreasing toward one side in the circumferential direction from the end of the first inclined portion 61 A. Adjacent ones of the plurality of the mountain-shaped portions 61 arranged in the circumferential direction are structured to be linked with each other respectively. That is, the reinforcement body 60 is continuous in the circumferential direction. Therefore, the troublesomeness of the operation for mounting the reinforcement body 60 on the housing main body can be reduced in comparison with a case where a plurality of discontinuous reinforcement bodies are provided.

[0079] (11) In this embodiment of the invention, the reinforcement body 60 includes the plurality of the joint portions 62 that are alternately provided in the circumferential direction. Therefore, the joint portions 62 are arranged at a plurality of locations along the circumference of the neck portion 35. That is, the entire neck portion 35 can be reinforced in comparison with a case where the neck portion 35 is joined only at one location.

[0080] (12) In this embodiment of the invention, the reinforcement body 60 is wound around the neck portion 35 along the entire circumference thereof. Therefore, the neck portion 35 can be more preferably restrained from being deformed than in a case where the reinforcement body 60 is provided on the neck portion 35 only along part of the circumference thereof.

[0081] (Other Embodiments) It should be noted that the mode of implementing the invention is not limited to the foregoing respective embodiments of the invention. For example, the invention can also be implemented in modified modes that will be described below. Further, the following respective modification examples are applied not only to the foregoing respective embodiments of the invention, but it is also possible to combine the different modification examples with one another to implement them.

[0082] In the foregoing first embodiment of the invention, each of the reinforcement bodies 50 adopts the construction including the two circular arc-like joint portions 51 corresponding to the inner periphery of the neck portion 35, and the rectification portion 52 that connects the two joint portions 51 to each other. However, the reinforcement bodies are not limited to this construction. For example, as shown in FIG. 10, a reinforcement body 53 including an annular joint portion 54 joined to the inner peripheral face of the neck portion 35 and a plurality of rectification portions 55 arranged in a reticular pattern inside the joint portion 54 can also be joined to the inside of the neck portion 35.

[0083] In the foregoing first embodiment of the invention, the respective reinforcement bodies 50 are joined to the neck portion 35 such that the respective rectification portions 52 extend perpendicularly to each other when the respective reinforcement bodies 0 are projected onto the flow channel cross-section along the radial direction of the neck portion 35. However, it is also possible to join the respective reinforcement bodies 50 to the neck portion 35 such that the rectification portions 52 form an angle other than 90° therebetween when the respective reinforcement bodies 50 are projected onto the flow channel cross-section.

[0084] In the foregoing first embodiment of the invention, the respective reinforcement bodies 50 are arranged such that the rectification portion 52 of one of the reinforcement bodies 50 and the rectification portion 52 of the other reinforcement body 50 are partially in contact with each other. However, it is also possible to arrange the respective reinforcement bodies 50 such that the rectification portions 52 are out of contact with each other, namely, so as to be spaced apart from each other in the length direction of the exhaust passage 80.

[0085] In the foregoing first embodiment of the invention, each of the reinforcement bodies 50 adopts the construction having the circular arc-like joint portions 51. However, it is also possible to change the shape of the joint portions 51 to an annular shape. It should be noted that one joint portion 51 is provided for each of the reinforcement bodies 50 in this case.

[0086] In the foregoing first embodiment of the invention, the two reinforcement bodies 50 are joined to the neck portion 35. However, it is also possible to dispense with one of the reinforcement bodies 50 and join only the other reinforcement body 50 to the neck portion 35. Further, it is also possible to join, in addition to the aforementioned two reinforcement bodies 50, one or a plurality of reinforcement bodies 50 to the neck portion 35. That is, it is also possible to join a total of three or more reinforcement bodies 50 to the neck portion 35.

[0087] In the foregoing first embodiment of the invention, each of the reinforcement bodies 50 adopts the construction in which the joint portions 51 are provided at both the ends of the rectification portions 52 respectively. However, it is also possible to dispense with the two joint portions 51 and directly join the rectification portions 52 to the inner peripheral face 35 A of the neck portion 35.

[0088] In the foregoing first embodiment of the invention, each of the reinforcement bodies 50 adopts the construction including the joint portions 51 and the rectification portions 52. However, it is also possible to dispense with the rectification portions 52. That is, it is also possible to construct the reinforcement bodies with only the former of a function of reinforcing the neck portion 35 and a function of rectifying exhaust gas. In this case, it is also possible to adopt an annular shape as the shape of the joint portions 51.

[0089] In the foregoing second embodiment of the invention, the reinforcement body 60 adopts the construction in which the plurality of the mountain-shaped portions 61 are arranged in the circumferential direction and adjacent ones of the mountain-shaped portions 61 are connected to each other respectively. However, the reinforcement body is not limited to this construction. For example, as shown in FIG. 11, a pentagonal reinforcement body 65 with the neck portion 35 serving as an inscribed circle can also be employed. In this case, the reinforcement body 65 and the neck portion 35 are joined to each other at joint portions 66 where inner peripheral faces 65 A of respective sides of the reinforcement body 65 are in contact with the neck portion 35. Further, between one region where the reinforcement body 65 and the neck portion 35 are joined to each other and another joined region adjacent thereto, there is formed a gap 67 between each of the inner peripheral faces 65A of the reinforcement body 65 and the outer peripheral face 35B of the neck portion 35. It should be noted that the reinforcement body can also assume a polygonal shape other than the pentagonal shape, with the neck portion 35 serving as an inscribed circle.

[0090] In the foregoing second embodiment of the invention, all the joint portions 62 of the reinforcement body 60 are joined to the neck portion 35. However, it is also possible to make a shift to a construction in which one or some of the joint portions 62 are not joined to the neck portion 35. In the foregoing second embodiment of the invention, the reinforcement body 60 adopts the construction in which the plurality of the mountain-shaped portions 61 identical in circumferential length to one another are arranged in the circumferential direction. However, it is also possible to make a shift to a construction in which mountain-shaped portions 61 different in circumferential length from one another are arranged in the circumferential direction. Mentionable as one example is a construction in which mountain-shaped portions 61 with a relatively long circumferential length and mountain-shaped portions 61 with a relatively short circumferential length are alternately arranged in the circumferential direction.

[0091] In the foregoing second embodiment of the invention, the reinforcement body 60 is provided on the outer peripheral face 35B of the neck portion 35 entirely along the circumferential direction. However, it is also possible to employ a reinforcement body assuming a shape corresponding only to part of the outer peripheral face 35B. Mentionable is one example is an annular discontinuous reinforcement body obtained by notching part of an annular reinforcement body.

[0092] In each of the foregoing embodiments of the invention, the neck portion

35 constituting an inlet region of the scroll passage 81 is provided with the reinforcement bodies 50 or the reinforcement body 60. However, it is also possible to provide the cylinder portion 41 of the base body 40 as a neck portion with the reinforcement bodies 50 or the reinforcement body 60.

[0093] In each of the foregoing embodiments of the invention, the reinforcement bodies 50 or the reinforcement body 60 and the neck portion 35 are joined together through brazing. However, this does not limit the method of joining the reinforcement bodies 50 or the reinforcement body 60 and the neck portion 35 together. For example, it is also possible to adopt a method of joining the reinforcement bodies 50 or the reinforcement body 60 and the neck portion 35 together by melting a base material itself, a method of joining the reinforcement bodies 50 or the reinforcement body 60 and the neck portion 35 together by press fitting or caulking, or a method of joining the reinforcement bodies 50 or the reinforcement body 60 and the neck portion 35 together with the aid of fastening members such as bolts or the like.

[0094] In each of the foregoing embodiments of the invention, the turbine housing 11 adopts the construction in which the scroll body 30, the base body 40, the inlet flange 71, and the outlet flange 72, which are formed separately from one another, are joined to one another. However, the turbine housing 11 is not limited to this construction. For example, at least one of the aforementioned respective structural bodies formed separately from one another can also be formed by being further divided into a plurality of structural bodies. Further, at least two of the aforementioned respective structural bodies can also be constructed as a single structural body.

[0095] In each of the foregoing embodiments of the invention, the sheet metal scroll body is adopted as the scroll body 30. However, it is also possible to replace the scroll body 30 with a cast scroll body or a resinous scroll body. In each of the foregoing embodiments of the invention, the cast base body is adopted as the base body 40. However, it is also possible to replace the base body 40 with a sheet metal base body or a resinous base body.

[0096] In each of the foregoing embodiments of the invention, the invention is applied only to the former of the turbine housing 1 1 and the compressor housing 12. However, the invention can also be applied to the respective housings. Further, the invention can also be applied only to the compressor housing 12.

[0097] While the invention has been described with reference to the example embodiments thereof, it is to be understood that the invention is not limited to the described embodiments or constructions. To the contrary, the invention is intended to cover various modifications and equivalent arrangements. In addition, while the various elements of the disclosed invention are shown in various example combinations and configurations, other combinations and configurations, including more, less or only a single element, are also within the scope of the appended claims.

Claims

CLAIMS:

1. A wheel housing of a turbocharger with a gas passage formed inside a housing main body and with a neck portion, which forms an end of the gas passage, included as part of the housing main body, wherein

the neck portion is provided, on an inside thereof, with a reinforcement body formed separately from the housing main body.

2. The wheel housing according to claim 1 , wherein the reinforcement body includes a joint portion joined to an inner peripheral face of the neck portion, and a rectification portion that rectifies flow of a gas.

3. The wheel housing according to claim 1 , wherein the reinforcement body includes two circular arc joint portions corresponding to an inner periphery of the neck portion, and a cylindrical rectification portion that connects the two joint portions to each other.

4. The wheel housing according to claim 1, wherein the reinforcement body includes an annular joint portion joined to the inner peripheral face of the neck portion, and a plurality of rectification portions arranged in a reticular pattern inside the joint portion is joined to the inside of the neck portion.

5. The wheel housing according to claim 2, wherein the rectification portion is in a columnar shape,

the joint portion is in a circular arc shape along an inner periphery of the neck portion on a flow channel cross-section perpendicular to a direction in which the gas flows through the gas passage, and

the joint portion has a chord longer than a width of the rectification portion.

6. The wheel housing according to claim 5, wherein the reinforcement body is provided as a first reinforcement body and a second reinforcement body, and

the neck portion is provided with the first reinforcement body and the second reinforcement body in such a manner that respective rectification portions of the first reinforcement body and the second reinforcement body intersect with each other when the respective reinforcement bodies are projected onto the flow channel cross-section.

7. The wheel housing according to claim 6, wherein the neck portion is provided with the first reinforcement body and the second reinforcement body in such a manner that the respective rectification portions of the first reinforcement body and the second reinforcement body are perpendicular to each other when the respective reinforcement bodies are projected onto the flow channel cross-section.

8. A wheel housing of a turbocharger with a gas passage formed inside a housing main body and with a neck portion, which forms an end of the gas passage, included as part of the housing main body, wherein

the neck portion is provided, on an outside thereof, with a reinforcement body formed separately from the housing main body, and

the reinforcement body includes a first region joined to an outside of the neck portion, and a second region provided adjacently to the first region in a circumferential direction of the neck portion with a gap between the second region and the neck portion.

9. The wheel housing according to claim 8, wherein the neck portion has a circular cross-sectional contour on a face perpendicular to a direction in which a gas flows through the gas passage, and

the reinforcement body is in a polygonal cross-sectional shape with the outside of the neck portion being an inscribed circle of the polygonal cross-sectional shape, on a plane perpendicular to the direction in which the gas flows through the gas passage.

10. A wheel housing of a turbocharger with a gas passage formed inside a housing main body and with a neck portion, which forms an end of the gas passage, included as part of the housing main body, wherein

the neck portion is provided, on an outside thereof, with a flange formed separately from the housing main body and having an exhaust pipe and an intake pipe connected thereto, and a reinforcement body formed separately from the housing main body and located opposite the exhaust pipe or the intake pipe with respect to the flange, and

the flange and the reinforcement body have a gap formed therebetween.

11. The wheel housing according to claim 10, wherein the reinforcement body includes a first region joined to the outside of the neck portion, and a second region having a gap from the neck portion.

12. The wheel housing according to claim 8 or 11 , wherein the reinforcement body includes a plurality of the first regions and a plurality of the second regions, and

the first regions and the second regions are alternately provided in a circumferential direction.

13. The wheel housing according to claim 8, 11 or 12, wherein the reinforcement body has a structure equipped with a plurality of mountain-shaped portions each including a region A where the gap formed between the reinforcement body and the neck portion gradually increases toward one side in a circumferential direction, and a region B where the gap formed between the reinforcement body and the neck portion gradually decreases from an end of the region A toward the one side in the circumferential direction, with adjacent ones of the plurality of the mountain-shaped portions, which are arranged in the circumferential direction, joined to each other respectively, and

the adjacent ones of the mountain-shaped portions are joined to each other respectively in a region equivalent to the second region of the reinforcement body.

14. The wheel housing according to any one of claims 1 to 13, wherein the housing main body and the reinforcement body are joined to each other through brazing.

15. The wheel housing according to any one of claims 1 to 14, wherein the housing main body is equipped with a sheet metal scroll body including a scroll-shaped region and the neck portion, and a base body including a flange portion joined to the scroll body, and

the gas passage is formed between the scroll body and the base body.

16. A turbine housing of a turbocharger that is constructed as the wheel housing according to any one of claims 1 to 15.

17. The turbine housing according to claim 16 that includes, as the neck portion, an inlet-side neck portion provided on an exhaust gas inlet side and an outlet-side neck portion provided on an exhaust gas outlet side, and

the reinforcement body is provided on the inlet-side neck portion and not on the outlet-side neck portion.

18. A compressor housing of a turbocharger that is constructed as the wheel housing according to any one of claims 1 to 15.

19. The compressor housing according to claim 18 that includes, as the neck portion, an inlet-side neck portion provided on an intake air inlet side and an outlet-side neck portion provided on an intake air outlet side, and

the reinforcement body is provided on the outlet-side neck portion and not on the inlet-side neck portion.

20. A turbocharger including the wheel housing according to any one of claims 1 to

19.