JP4448064B2 - Turbine housing - Google Patents

Description

  The present invention relates to a turbine housing, and more particularly, to a turbine housing of a turbocharger including an inner housing and an outer housing that covers the inner housing.

  As a turbine housing of the turbocharger, a cast housing is generally used. On the other hand, a turbine housing made of sheet metal has also been proposed in, for example, Patent Document 1, in which an inner housing and an outer housing made of sheet metal are formed by appropriately processing a metal plate, and the inner housing has a gap. It is the structure covered with an outer housing. In this turbine housing, the inner housing is formed in two parts and fitted together, and one end of the inner housing on the exhaust gas outlet side is slidably supported in the turbine axial direction, thereby directly It provides relief when the receiving inner housing is thermally expanded to relieve stress on the inner housing.

JP 2002-004871 A

  However, in the turbine housing described in Patent Document 1, exhaust gas may flow into the gap between the outer housing and the inner housing from the fitting portion of the inner housing (see FIGS. 1 and 4 of Patent Document 1). The exhaust gas leaks to the downstream side of the turbine through the slide support portion without passing through the turbine wheel due to the end portion of the inner housing being slidably supported. There is. In this case, a part of the exhaust gas is discarded without performing any work, and there is a problem that the turbine efficiency is lowered.

  Therefore, an object of the present invention is to provide a turbine housing capable of preventing a decrease in turbine efficiency by using exhaust gas without waste.

  In order to achieve the above object, a turbine housing according to the present invention includes a shroud member for surrounding a shroud portion of a turbine wheel in a turbine housing including an inner housing and an outer housing covering the inner housing, A gap is formed by the shroud member and the outlet side end portion of the outer housing, the outlet side end portion of the inner housing is inserted into the gap, and the gap is closed with respect to the outlet side of the turbine wheel. The turbine wheel is opened upstream of the turbine wheel.

  In this turbine housing, the gap formed by the shroud member and the outlet side end portion of the outer housing is closed with respect to the outlet side of the turbine wheel, so that leakage of exhaust gas from the gap to the outlet side of the turbine wheel is prevented. Is done. Further, since the gap is opened to the upstream side of the turbine wheel, the exhaust gas existing in the gap flows to the upstream side of the turbine wheel and is used for driving the turbine wheel. As a result, a decrease in turbine efficiency can be prevented.

  It is preferable that an outlet side end portion of the inner housing is slidably inserted into the gap. Thereby, the exit side edge part of an inner side housing is supported so that a slide is possible.

  Further, a fitting portion is provided in which the inner housing and the outer housing are slidably fitted to each other at their outlet side end portions, and the outer side of the inner housing and the outer housing are arranged at the outlet side end portion of the inner housing. It is preferable that a thick portion that protrudes toward the housing and slidably contacts the outer housing is provided. Thereby, even if the inner housing is thermally deformed by the heat of the exhaust gas, the thick portion slides, so that it is possible to appropriately relieve stress. In addition, since the inner housing has a thick portion that contacts the outer housing, the rigidity of the inner housing can be improved at the thick portion, and the fitting accuracy between the thick housing and the outer housing can be improved. The machining allowance for increasing the height can be secured in the inner housing.

  Further, the shroud member is preferably made of a pipe material. Thereby, a shroud member can be produced cheaply and easily by press working or the like.

  Furthermore, it is preferable that the inner housing and the outer housing are made of sheet metal. Thus, the inner housing and the outer housing are relatively easily and inexpensively manufactured.

  Alternatively, it is preferable that the inner housing is made of cast metal and the outer housing is made of sheet metal. Thereby, the freedom degree of design of an inner side housing can be improved. Further, the outer housing can be manufactured relatively easily and inexpensively. Since the inner housing is made of casting, for example, the thickness can be appropriately set for each part as necessary, and the thickness can be partially increased.

  Another turbine housing according to the present invention is a turbine housing including an inner housing and an outer housing covering the inner housing, wherein the inner housing is made of cast metal and the outer housing is made of sheet metal. And Thereby, it becomes possible to improve the design freedom of the inner housing. Further, as described above, the outer housing can be manufactured relatively easily and inexpensively. Since the inner housing is made of casting, for example, the thickness can be appropriately set for each part as necessary, and the thickness can be partially increased.

  In the other turbine housing according to the present invention, a fitting portion is provided in which the inner housing and the outer housing are slidably fitted to each other. In the fitting portion, the inner housing is connected to the outer housing side. It is preferable that a thick portion that protrudes into the outer housing and slidably contacts the outer housing is provided. Thereby, even if the inner housing is thermally deformed by the heat of the exhaust gas, the thick portion slides, so that it is possible to appropriately relieve stress. In addition, since the inner housing has a thick portion that contacts the outer housing, the rigidity of the inner housing can be improved at the thick portion, and the fitting accuracy between the thick housing and the outer housing can be improved. The machining allowance for increasing the height can be secured in the inner housing. As a result, the sealing performance of the fitting portion can be improved, the exhaust gas can be prevented from leaking, and the turbine efficiency can be prevented from being lowered.

  Further, in the other turbine housing according to the present invention, the inner housing defines a bypass passage for bypassing exhaust gas from the upstream side to the downstream side of the turbine wheel, and the outlet portion of the bypass passage and the inner side Preferably, the outlet side end portion of the housing is provided side by side, and the outlet side end portion of the inner housing extends at least downstream from the outlet portion of the bypass passage. This prevents the bypassed exhaust gas flow from interfering with the exhaust gas flow after rotating the turbine wheel.

  According to the present invention, an excellent effect is exhibited that exhaust gas can be used without waste and deterioration of turbine efficiency can be prevented.

  Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings. In addition, the turbine housing which concerns on the following embodiment is applied to the radial type turbine of the turbocharger for vehicles.

  The external view of the turbine housing 1 of 1st embodiment is shown in FIGS. 1 is a side view of the turbine housing 1, FIG. 2 is a front view thereof, and FIG. 3 is a rear view thereof. FIG. 1 shows the flow of exhaust gas with white arrows. Exhaust gas from an engine (not shown) enters the turbine housing 1 from the lower inlet 70 in the figure, turns at a right angle in the turbine housing 1, and exits the turbine housing 1 from the outlet 80 along the turbine axial direction. To be discharged. An inlet side flange portion 30 is provided in the vicinity of the inlet 70, and the inlet side flange portion 30 is used for connection to an exhaust pipe or an exhaust manifold (not shown) on the engine side. An outlet side flange portion 40 is provided in the vicinity of the outlet 80, and the outlet side flange portion 40 is used for connection to an exhaust pipe (not shown) on the downstream side. A center flange 50 used for connection with the center housing 5 (see FIG. 5) is also provided.

  Cross-sectional views of the turbine housing 1 are shown in FIGS. 4 and 5. 4 is a cross-sectional view taken along line AA in FIG. 1, in other words, a cross-sectional view cut along a plane orthogonal to the turbine axis L. FIG. FIG. 5 is a cross-sectional view taken along the line BB in FIG. 2, in other words, a cross-sectional view cut along a plane including the turbine axis L.

  As understood from these drawings, the turbine housing 1 has a so-called double-shell structure including an inner housing 10 and an outer housing 20 made of sheet metal that can be press-molded together. The inner housing 10 substantially defines an exhaust gas flow path inside the housing, and the outer housing 20 covers the inner housing 10 through the gap G, protects the inner housing 10 and simultaneously insulates it, and the turbine housing 1. It is an outer shell or structure that also plays a role of increasing rigidity. The exhaust gas flow path defined by the inner housing 10 is, in order from the upstream side, an inlet 70, a run-up chamber S1, a scroll chamber S2, a turbine wheel chamber S3, an outlet chamber S4, and an outlet 80. A turbine wheel chamber S3 is formed radially inward, and the turbine wheel 1a is rotatably accommodated in the turbine wheel chamber S3. The gap G between the inner housing 10 and the outer housing 20 has heat resistance, corrosion resistance, and flexibility such as SUS mesh and ceramic wool in order to maintain the gap and maintain the shape of the inner housing 10 and heat insulation. The filling member can be disposed in whole or in part.

  As shown in FIG. 5, the center flange portion 50 of the turbine housing 1 is connected and fixed to one end of the center housing 5. For this fixing, a fastener 51 having a U-shaped cross section and a ring shape as shown in the figure is used. A compressor housing (not shown) is connected and fixed to the other end of the center housing 5, and a compressor wheel coaxially connected to the turbine wheel 1 a by the turbine shaft 5 a is accommodated in the compressor housing.

  The inner housing 10 is divided and formed from two members, a first inner housing member 11 and a second inner housing member 12, and is manufactured by fitting each other and fixing them by welding or the like over the entire circumference. The Specifically, the first inner housing member 11 and the second inner housing member 12 are formed so as to divide the inner housing 10 into two parts on a plane orthogonal to the turbine axis L. The division position along the turbine axis L is in the vicinity of the outermost diameter position of the scroll chamber S2, and is a position where the run-up chamber S1 and the scroll chamber S2 are divided in half. The first inner housing member 11 is positioned closer to the front end side in the turbine axial direction than the second inner housing member 12. The first inner housing member 11 and the second inner housing member 12 are each made of sheet metal produced by press-molding a metal plate material. This makes it relatively easy and inexpensive to manufacture. The thickness of the metal plate material is, for example, 0.4 mm to 2.0 mm, and a material that is thinner than the metal plate material forming the outer housing 20 is used. As the metal plate material of the inner housing 10, a material excellent in corrosion resistance and heat resistance is adopted, and stainless steel, for example, is used. The inner housing according to the present invention is not limited to such a configuration, size, material and the like. The inner housing may be divided in different ways.

  As shown in FIG. 4, the inner housing 10 is provided with a tongue-like tongue T so that the exhaust gas flows smoothly from the running chamber S1 to the scroll chamber S2. As shown in FIG. 6, the tongue T is formed by joining the convex flat tongue portions 13 and 14 formed on the first and second inner housing members 11 and 12 at the joint surfaces 13 a and 14 a. It is fixed by welding or the like. The run-up room S1 is a space from the entrance 70 to the downstream end of the tongue T. Positioning portions that are adapted to each other are provided at the base end positions of the tongue portions 13 and 14. Only the positioning part of one tongue part 13 is shown by 13b in FIG. Positioning of the first inner housing member 11 and the second inner housing member 12 in the rotational direction is achieved by fitting or fitting the positioning portions to each other when the first inner housing member 11 and the second inner housing member 12 are fitted. Can be easily and accurately performed. In the inner housing 10, a bypass hole 17 for exhaust bypass is provided in the run-up chamber S1.

  On the other hand, the outer housing 20 is divided and formed from two members, a first outer housing member 21 and a second outer housing member 22, like the inner housing 10. It is produced by fixing with. The first outer housing member 21 and the second outer housing member 22 are formed so as to divide the outer housing 20 in two on a plane orthogonal to the turbine axis L, and the dividing position along the turbine axis L is the inner housing. 10 is the same. The first outer housing member 21 and the second outer housing member 22 are each made of sheet metal produced by press-molding a metal plate material. This makes it relatively easy and inexpensive to manufacture. The thickness of the metal plate material is thicker than that of the inner housing 10 and is, for example, 1.5 mm to 3.0 mm. As the metal plate material of the outer housing 20, a material excellent in corrosion resistance and heat resistance is adopted, and for example, austenitic stainless steel or ferritic stainless steel is used. The outer housing according to the present invention is not limited to such a configuration, size, material, and the like. However, since the outer housing 20 is an outer shell of the turbine housing 1, it is required to have a certain level of strength and rigidity.

  The outer housing 20 includes an inlet side end portion 23 (see FIG. 7), an outlet side end portion 24, and a bypass hole 25. The bypass hole 25 is aligned with the bypass hole 17 of the inner housing 10 and is used for exhaust bypass. The bypass holes 25 together with the bypass holes 17 define a bypass passage P for bypassing the exhaust gas from the upstream side to the downstream side of the turbine wheel 1a. The bypass hole 25 is opened and closed from the outlet 80 side by a waste gate valve (not shown) (see FIG. 3).

  As shown in FIG. 4 and FIG. 7, the inlet side flange portion 30 is manufactured by pressing a thick (5 to 15 mm) metal plate material, for example. Here, the inlet side end portion 23 of the outer housing 20 is inserted into the inlet side flange portion 30 and fixed by welding or the like. The inlet side flange portion 30 is provided with a step portion 31 for positioning the inlet side end portion 23 of the outer housing 20.

  On the other hand, the inlet-side end 15 of the inner housing 10 is simply slidably fitted inside the inlet-side end 23 of the outer housing 20, whereby the inner housing 10 and the outer housing 20 are fitted together. The thermal deformation difference is absorbed. That is, during the turbine operation, the inner housing 10 directly receives the heat of the exhaust gas and becomes a high temperature. Therefore, the inner housing 10 has a larger thermal expansion amount than the outer housing 20. The difference in thermal expansion at this time is absorbed by the sliding movement of the inlet side end portion 15 of the inner housing 10 with respect to the inlet side end portion 23 of the outer housing 20, and the shape of the flow path in the inner housing 10 is maintained, and the inner housing 10 is maintained. To reduce the stress acting on the surface. In other words, this slide portion is a relief for the inner housing 10 for absorbing the difference in thermal expansion. Such a slide portion is also provided on the outlet side, which will be described later. In the turbine housing 1, the inner housing 10 is slidably supported at two locations, the inlet side and the outlet side. When viewed microscopically, the slide portion has a gap at the boundary between the members, and a small amount of exhaust gas passes through the gap. This point will be described in detail later. The gap on the inlet side is exaggerated in FIG. 7 and is indicated by G4. This gap G4 communicates with the main gap G. The gap G4 is, for example, 0.1 mm to 0.25 mm.

  On the other hand, as shown in FIG. 5, the inner housing 10 and the outer housing 20 are connected and fixed to the center flange portion 50 by welding or the like. The inner housing 10 is connected and fixed to the inner end surface 52 of the center flange portion 50, and the outer housing 20 is connected and fixed to a step portion 53 formed in the center flange portion 50.

  On the outlet side of the turbine housing 1, an outlet side flange portion 40 is attached to the outlet side end portion 24 of the outer housing 20 via an outlet pipe 41. The outlet side end portion 24 of the outer housing 20 has a cylindrical shape as a whole, and is formed in a crank shape so that the end portion 24a is reduced in diameter, and one end portion of the outlet pipe 41 is fitted outside the end portion 24a. And fixed by welding or the like. The other end portion of the outlet pipe 41 is bent at a right angle by pressing or the like, and a flat ring-shaped outlet flange portion 40 is fixed thereto by welding or the like. The outlet side flange portion 40 can be produced by cutting or casting a pipe material. The outlet chamber 41 and the outlet 80 are formed by the outlet pipe 41 and the outlet-side flange portion 40.

  In particular, the turbine housing 1 of the first embodiment includes a shroud member 60 for surrounding the shroud portion 1d of the turbine wheel 1a. The shroud member 60 is formed in a cylindrical shape, and its upstream portion 60a is flared so as to follow the shroud curve of the shroud portion 1d of the turbine wheel 1a, and its downstream end portion 60b is the end portion of the outer housing 20. It fits inside 24a and is fixed by welding or the like over the entire circumference. As a result, the shroud member 60 has a center on the turbine axis L and is arranged coaxially with the cylindrical outlet side end 24 of the outer housing 20.

  In particular, in the first embodiment, the shroud member 60 is made of a tube material, and can be easily and inexpensively manufactured by bending the tube material by press working. The clearance (chip clearance) between the shroud portion 1d of the turbine wheel 1a and the shroud member 60 is important because it affects the turbine efficiency. Therefore, in order to maintain this chip clearance with high accuracy, the surface of the shroud member 60 facing the shroud portion 1d is finished with high accuracy by machining. However, if accuracy can be obtained only by bending, machining may be omitted. The thickness of the pipe material forming the shroud member 60 is larger than the inner housing 10 in consideration of machining allowance when machining is performed (for example, about 1.5 mm to 3.0 mm), and the inner housing when machining is not performed. Thicker than 10 or equivalent. In addition, when the thickness of the shroud member 60 is increased, the rigidity thereof is increased and thermal deformation during operation is suppressed. Since the high-temperature exhaust gas passes inside the shroud member 60, the shroud member 60 is made of a material having excellent heat resistance and corrosion resistance. The shroud member 60 forms a turbine wheel chamber S3.

  When the shroud member 60 is assembled to the outer housing 20 in this manner, a ring-shaped gap G0 is formed between the outer housing 20 and the shroud member 60. The gap G0 is closed with respect to the outlet side of the turbine wheel 1a, that is, the outlet chamber S4 and the outlet 80 by the fixing portion, that is, the closing portion between the outlet side end portion 60b of the shroud member 60 and the end portion 24a of the outer housing 20, and the other side. The upstream side of the turbine wheel 1a, that is, the scroll chamber S2, is opened. The outlet side end portion 16 of the inner housing 10 is inserted into the gap G0. The outlet side end portion 16 of the inner housing 10 is formed to project from the scroll chamber forming portion 11a of the first inner housing member 11 toward the outlet side, and is formed in a cylindrical shape as a whole, and is formed on the outer peripheral surface of the shroud member 60. It is set as the curved shape which follows. And the tip part is inserted in gap G0. In this insertion portion, the outlet side end portion 16 is slidable, that is, the inner peripheral surface of the outlet side end portion 16 is slidable with respect to the outer peripheral surface of the shroud member 60, and the outer peripheral surface of the outlet side end portion 16 is outside. The housing 20 is slidable with respect to the inner peripheral surface of the outlet side end portion 24.

  In this way, the outlet side end portion 16 of the inner housing 10 is supported so as to be slidable in the turbine axis L direction, and a slide support portion that absorbs a thermal deformation difference between the inner housing 10 and the outer housing 20 is also formed on the turbine outlet side. Will be. Even in this slide support portion, there is a gap at the boundary between the members when viewed microscopically. As exaggeratedly shown in FIG. 8, this gap is a gap G1 between the outlet side end portion 16 and the outer housing 20, and a gap G3 between the outlet side end portion 16 and the shroud member 60. The gaps G1 and G3 are, for example, 0.1 mm to 0.25 mm. There is a relatively large gap G2 between the outlet side end portion 16 and the closing portion, and the movement of the outlet side end portion 16 is sufficiently allowed by this gap G2. In the first embodiment, the outlet side end 16 in the vicinity of the scroll chamber forming portion 11a is overlapped with the shroud member 60, and a gap communicating with the gap G3 is formed at these boundary portions. Hereinafter, these are collectively referred to as a gap G3.

  Eventually, as shown in FIG. 8, a U-turn-shaped flow path is formed by the gaps G1, G2, and G3, and this flow path is upstream of the main gap G between the inner housing 10 and the outer housing 20. The end is connected in communication and the downstream end is connected in communication with the scroll chamber S2 immediately before the leading edge portion 1c of the turbine wheel 1a.

  Next, the operation and effect of the turbine housing 1 of the first embodiment will be described in detail.

  During operation of the turbocharger, exhaust gas from the engine enters the turbine housing 1 through the inlet 70, passes through the run-up chamber S1 and the scroll chamber S2, and enters the turbine wheel chamber S3, where the turbine wheel 1a is rotationally driven. To do. Then, it discharges | emits from the exit 80 through exit chamber S4. The compressor wheel is rotationally driven by the rotational drive of the turbine wheel 1a, and air is supercharged to the engine.

  On the other hand, the exhaust gas flows into the gap G from the gap G4 shown in FIG. As indicated by the arrows in FIG. 8, the exhaust gas reaches the outlet-side gap G0 and returns to the upstream side of the turbine wheel 1a through the gaps G1, G2, and G3 in order. Since the gap G0 is closed to the outlet side of the turbine wheel 1a, the exhaust gas flowing into the gap G can pass through the turbine wheel 1a (between the outer peripheral surface of the shroud portion 1d and the inner peripheral surface of the shroud member 60). Without leaking to the exit chamber S4 side. On the other hand, since this gap G0 is opened upstream of the turbine wheel 1a, all the exhaust gas flowing into the gap G is used for driving the turbine wheel 1a. Eventually, all the exhaust gas flowing into the gap G can be recovered and used for driving the turbine wheel 1a without being wasted, so that it is possible to prevent a decrease in turbine efficiency.

  Moreover, since the shroud member 60 of the first embodiment is manufactured by appropriately processing a pipe material, it can be easily and inexpensively manufactured. However, the shroud member referred to in the present invention includes those other than the pipe material, and may be, for example, a cast product. The shroud member 60 is fixed only at the outlet side end portion 60b, and the upstream side end portion on the opposite side can be thermally expanded and contracted. Thereby, the thermal stress of the shroud member 60 can also be relieved. Further, since the shroud member 60 has an axially symmetric cylindrical shape, thermal deformation also becomes axially symmetric, that is, only expands or contracts the diameter. Therefore, it is possible to maintain the tip clearance well over the entire circumference. Further, since the shroud member 60 is a separate member from the inner housing 10, even if the inner housing 10 deteriorates due to repeated thermal deformation or the like, the influence does not reach the shroud member 60 and does not affect the chip clearance. . Accordingly, it is possible to avoid the deterioration of the turbine performance due to the deterioration of the inner housing 10.

  As described above, the outlet side end portion 16 of the inner housing 10 inserted into the gap G0 is movable. Therefore, even if the inner housing 10 expands due to heat from the exhaust gas, the outlet side end portion of the inner housing 10 is expanded. When the portion 16 moves (that is, escapes), stress on the inner housing 10 is relieved, and deterioration of the turbine housing 1 is suppressed. That is, if the outlet end 16 is fixed and restrained to the outer housing 20 or the like, the turbine housing 1 will be deteriorated earlier due to the stress when the inner housing 10 is thermally expanded. Further, since the outlet side end portion 16 of the inner housing 10 moves in the turbine axis L direction to buffer the thermal expansion and contraction of the inner housing 10, the radial extension of the inner housing 10 is suppressed. Even if the inner housing 10 protrudes radially inward, the strong shroud member 60 exists around the turbine wheel 1a and protects the turbine wheel 1a. Is reliably prevented.

  Similarly, since the slide support portion for the inner housing 10 is also provided on the inlet side of the turbine housing 1, the stress during the thermal expansion of the inner housing 10 is relieved by the extension of the inner housing 10 toward the running chamber, and the turbine Deterioration of the housing 1 is suppressed.

  Further, the turbine housing 1 has a double shell structure as described above. Therefore, the thickness of the housing (in the case of the first embodiment, the total thickness of the inner housing 10 and the outer housing 20) can be reduced as compared with the case where the turbine housing is an integral cast product. Moreover, the heat insulation effect is exhibited by the gap G, and heat dissipation from the inside to the outside of the inner housing 10 is suppressed. Therefore, heat is suppressed from being removed from the exhaust gas in the turbine housing 1, and higher temperature exhaust gas is discharged from the turbine housing 1. When there is an exhaust purification catalyst on the downstream side of the turbine housing 1, it is possible to contribute to early activation of the catalyst after engine cold start. In addition, since the thickness of the housing is reduced, the supercharger can be reduced in weight, which leads to improved fuel efficiency. When the gap G between the inner housing 10 and the outer housing 20 is filled with a member such as ceramic wool, deformation of the inner housing 10 can be suppressed at the same time as filling the space, and further, exhaust gas to the gap G can be suppressed. Inflow can also be suppressed, and degradation of turbine performance is suppressed even under relatively severe use conditions (such as when the exhaust gas temperature is high).

  As mentioned above, although the turbine housing which concerns on this invention was demonstrated based on 1st embodiment, this invention is not limited to this. For example, in the first embodiment, the shroud member 60 and the outer housing 20 are directly fixed to form the closed portion of the gap G0, but various structures of the closed portion can be considered. Another member (for example, the outlet pipe 41) may be interposed between the shroud member 60 and the outer housing 20, and these three members may be fixed together to form a closing portion. Further, a buffer member (for example, SUS mesh or ceramic wool (catalyst mat)) for improving the slide may be interposed in the slide portion on the outlet side and / or the inlet side of the turbine housing. The inner housing and the outer housing may be divided and formed on the side of the running chamber and the side of the scroll chamber. Alternatively, the first inner housing member 11 and the second inner housing member 12 may be integrally formed. The turbine housing according to the present invention can also be applied to other turbine types such as a mixed flow turbine and a variable capacity turbine.

  Next, a second embodiment of the present invention will be described based on FIG. In the turbine housing 101 of the second embodiment, as compared with the turbine housing 1 of the first embodiment, the inner housing 110 is made of cast metal instead of sheet metal, and a thick portion 118 is provided at the outlet end portion 116 thereof. It is different in point. Differences will be mainly described below, and common points are denoted by the same reference numerals in the drawings, and description thereof will be omitted. The appearance of the turbine housing 101 of the second embodiment is substantially the same as that of the first embodiment (see FIGS. 1 to 3). FIG. 9 is a cross-sectional view corresponding to the line BB in FIG.

  The inner housing 110 in the turbine housing 101 of the second embodiment is made of a casting and is manufactured as one piece. In the gap G0 between the outer housing 20 and the shroud member 60, a thick portion 118 formed at the distal end portion of the outlet side end portion 116 of the inner housing 110 is slidably inserted. The outlet side end portion 116 of the inner housing 110 is formed to protrude from the scroll chamber forming portion 111a of the inner housing 110 toward the outlet side, and is formed in a substantially cylindrical shape as a whole, and is formed on the outer peripheral surface of the shroud member 60. It is set as the curved shape which follows.

  The inner housing 110 and the outer housing 20 are slidably fitted to each other at their outlet side end portions 116 and 24 to form a fitting portion. The outlet side end portion 116 of the inner housing 110 is provided with a thick portion 118 that protrudes to the outer housing 20 side, that is, radially outward, and slidably contacts the outer housing 20. The outer peripheral surface of the thick portion 118 is preferably machined to have a predetermined fit tolerance with the abutment surface 26 of the outlet side end 24 of the outer housing 20. In other words, the thick portion 118 is provided to ensure a machining allowance for such machining. Thereby, the fitting state of the fitting portion is optimized, and the fitting accuracy can be increased. The advantage of the thick portion 118 will be described in detail later.

  In the turbine housing 101, since the inner housing 110 is manufactured by casting, the degree of freedom in designing the inner housing 110 can be increased. First, the inner housing 110 can be made substantially thin. The inner housing 110 of the second embodiment has substantially the same thickness as the outer housing 20, but the present invention is not limited to this, and the inner housing 110 may be thinner than the outer housing 20. Further, the inner housing 110 can be partially thinned or partially thickened, and the thickness can be changed so that the inner housing 110 has a necessary strength depending on each part. For this reason, both strength securing and weight reduction can be achieved. When the inner housing 110 is thin, it can be made, for example, about 2.0 mm or thinner. By using a thin inner housing, the heat of the exhaust gas is suppressed from being taken away by the inner housing 110, which is advantageous for warming up the catalyst. Furthermore, the degree of freedom of shape of the inner housing 110 is also increased. For example, the inner housing can be easily formed into a so-called twin scroll shape. Furthermore, it is possible to easily form a shape for a variable nozzle (VN) type turbocharger. Furthermore, it is suitable for a small turbocharger because it can easily produce a tightly bent shape or a complicated shape.

  As the material of the cast inner housing 110, cast iron, heat-resistant cast steel, or the like can be selected in view of the temperature of the exhaust gas. good.

  In the turbine housing according to the first and second embodiments, since the outer housing is arranged so as to cover the inner housing, regardless of whether the inner housing is made of sheet metal or casting, Even if the turbine wheel housed in the turbine housing breaks and the broken pieces break through the inner housing, it is possible to prevent the outer housing from scattering to the outside.

  By the way, as mentioned in the background art section, as a turbine housing of a turbocharger, an integral and single casting turbine housing is generally used. On the other hand, a turbine housing including a sheet metal inner housing and a sheet metal outer housing as in the first embodiment is suitable for the purpose of reducing the weight and reducing the heat capacity. On the other hand, as in the second embodiment, it is understood that the turbine housing in which the outer housing is made of sheet metal and the inner housing is made of casting is preferable in view of the advantages of the casting inner housing as described above. . Accordingly, an invention relating to a turbine housing provided with such a cast inner housing and a sheet metal outer housing (hereinafter, the invention will be referred to as the second invention, and the invention relating to the above-described embodiment will be referred to as the first invention). Will be described based on the embodiment. The embodiment of the second invention described below is different from the embodiment of the first invention in that the shroud member 60 is not provided. The same components as those of the first embodiment are designated by the same reference numerals in the drawing and description thereof is omitted. In any of the following embodiments, the appearance of the turbine housing is the same as that of the first embodiment (see FIGS. 1 to 3).

  As shown in FIGS. 10 and 11, the turbine housing 201 according to the first embodiment of the second invention has a so-called double-shell structure including a cast inner housing 210 and a sheet metal outer housing 20. Yes. In the inner housing 210 and the outer housing 20, the outlet side end portions 216 and 24 are fitted to each other, and the inlet side end portions 215 and 23 are also fitted to each other. The inner housing 210 is fitted to the center flange portion 50 at the center fitting portion 219, and eventually, the turbine housing 201 has three fitting portions (an inlet side fitting portion α, an outlet side fitting portion β, and A center side fitting portion γ) is formed. In order to absorb a difference in thermal expansion of the inner housing 210 relative to the outer housing 20 and reduce thermal stress on the inner housing 210, at least one of these three fitting portions can be slid. The portions that are not slidable are fixed to each other by welding or the like. In the case of the first embodiment of the second invention, the inlet side fitting portion α and the center side fitting portion γ are slidable, and the remaining fitting portion (outlet side fitting portion β) is fixed. The remaining fitting parts may be slidable. It is preferable that a gap in the diameter direction of the fitting portion is set to 0.25 mm or less at a place where sliding is possible. As the shroud member is omitted, the inner surface of the inner housing 210 surrounding the shroud portion of the turbine wheel (not shown) is machined. With the turbine housing 201 according to the first embodiment of the second invention, the above-described effects of the cast inner housing 210 can be exhibited.

  Next, the turbine housing which concerns on 2nd embodiment of 2nd invention is demonstrated based on FIG.12 and FIG.13. As shown in the figure, in the turbine housing 301, the inner housing 310 is formed in a twin scroll shape, and a partition wall 310P that partitions the scroll chamber is formed integrally with the inner housing 310. The three fitting portions α, β, and γ are all slidably fitted, and in particular, the inlet-side fitting portion α and the outlet-side fitting portion β are provided with thick portions 320, 318 on the inner housing 310. Is provided. The thick portions 320 and 318 are the same as those in the second embodiment (see FIG. 9) of the first invention, and the outer housing 20 is provided at the distal end portions of the inlet side end portion α and the outlet side end portion β. It protrudes to the side. The outer peripheral surfaces of the thick portions 320 and 318 are slidably brought into contact with the inner peripheral surfaces of the inlet side end portion 23 and the outlet side end portion 24 of the outer housing 20, respectively. The outer peripheral surfaces of the thick portions 320 and 318 are preferably machined to have a predetermined fit tolerance with the inner peripheral surfaces of the inlet side end 23 and the outlet side end 24 of the outer housing 20. In the center side fitting portion γ, a center fitting portion 319 similar to the above is provided in the inner housing 310. An insulator 55 that partitions a part of the exhaust gas passage is supported by the center flange portion 50 and provided in the opening inside the center side fitting portion γ.

  According to these thick portions 320 and 318, the sealing performance at the inlet side fitting portion α and the outlet side fitting portion β can be improved, and passage of exhaust gas can be prevented. That is, first, the machining allowance for machining can be sufficiently secured by the thick portions 320 and 318, and the fitting accuracy between the outer peripheral surface of the thick portions 320 and 318 and the inner peripheral surface on the contact side is not varied. High accuracy can be maintained. Further, the thick portions 320 and 318 can improve the rigidity of the inlet side end portion 315 and the outlet side end portion 316 which are free ends, and can suppress vibration during turbine operation. As a result, when the turbine is in operation, it is possible to maintain a suitable fitting state between the inner housing 310 and the outer housing 20, including during the thermal expansion of the inner housing 310, thereby improving the sealing performance of the fitting portion and allowing gas to pass. Can be prevented. In particular, according to the thick portion 318 of the outlet side fitting portion β, it is possible to prevent the exhaust gas from leaking to the outside and contribute to the improvement of turbine efficiency.

  Thus, although it is preferable to provide a thick part in the slidable fitting part, it is not necessarily essential. Also in the second embodiment of the second invention, the thick portion of the inlet side end 315 may be omitted as shown in FIG. 11 for the inlet side end 215 of the first embodiment. Further, as shown in FIG. 14, in the center side fitting portion γ, a thick portion 321 may be provided in the center fitting portion 319 of the inner housing 310 and the thick portion may be omitted from the outlet side fitting portion β.

  As described above, according to the second invention, since the inner housing is castable, its shape has a high degree of freedom. Therefore, in the third embodiment of the second invention described here, a member that is separate from the inner housing in the above-described embodiment is integrated with the inner housing. For example, as shown in FIG. 15, the center flange portion 422 may be formed integrally with the inner housing 410. In this case, since there is no center side fitting part, it is necessary to be able to slide at least one of the inlet side fitting part α and the outlet side fitting part β. Of course, it is preferable to provide a thick portion in the slidable fitting portion.

  Incidentally, as can be understood from FIG. 3, the outlet side end portion of the inner housing and the outlet portion of the bypass passage P are arranged in parallel in the above-described embodiments. When the waste gate valve is opened and the exhaust bypass is performed when the turbocharger is operated, the exhaust gas that has escaped from the bypass passage P interferes with the main exhaust gas after passing through the turbine wheel, thereby reducing turbine efficiency. It may cause. Therefore, a configuration for preventing such interference is employed in the following fourth embodiment of the second invention.

  As shown in FIGS. 16 and 17, in the fourth embodiment, the outlet side end portion 516 of the inner housing 510 extends so as to be positioned at least on the downstream side of the outlet portion P1 of the bypass passage P. That is, the front end 516A of the outlet side end portion 516 is positioned at the downstream side of at least the outlet end position of the bypass passage P indicated by X in FIG. A portion of the outlet side end portion 516 that is located on the downstream side of the position X is defined as an extending portion 516E. From the viewpoint of preventing the interference, it is preferable that the outlet side end portion 516 of the inner housing 510 extends as downstream as possible. In the fourth embodiment of the second invention, the position of the tip 516A of the outlet side end portion 516 is matched with the position of the surface 40A of the outlet side flange portion 40, that is, to the maximum length that does not protrude from the turbine housing. An outlet end 516 of 510 is extended. According to this, the bypass gas that has exited from the outlet portion P1 of the bypass passage P is prevented from flowing back and mixing into the inner housing 510 by the extending portion 516E as a partition wall. The mainstream exhaust gas after passing through the turbine wheel is guided to the outlet 80 by the extending portion 516E without being interfered by the bypass gas, and is discharged to the outside of the turbine housing 501. In particular, according to the configuration of the present embodiment, the outlet side end portion 516 extends to a marginal length that does not protrude from the turbine housing 501, so that at least interference in the turbine housing 501 is reliably prevented. Thereby, the escape of exhaust gas after passing through the turbine wheel 1a is improved, which can contribute to the improvement of turbine efficiency. Note that the length of the extending portion 516E may be determined so that the exhaust gas is preferably supplied to the catalyst on the downstream side of the turbine housing.

  Although the present invention has been described with a certain degree of concreteness, various modifications and changes can be made to the present invention without departing from the spirit and scope of the invention described in the claims. Must be understood. That is, the present invention includes modifications and changes that fall within the scope and spirit of the appended claims and their equivalents.

It is a right view of the turbine housing which concerns on 1st embodiment of this 1st invention. It is a front view of the turbine housing shown in FIG. It is a rear view of the turbine housing shown in FIG. It is sectional drawing along the AA line of FIG. It is sectional drawing along the BB line of FIG. It is sectional drawing along CC line of FIG. 4, and the 2nd inner housing member which is not shown by FIG. 4 is also shown collectively. FIG. 5 is an enlarged view of a portion I1 in FIG. 4. FIG. 6 is an enlarged view of a portion I2 in FIG. 5. FIG. 5 is a cross-sectional view corresponding to a cross section taken along line BB in FIG. 2 of the turbine housing according to the second embodiment of the first invention. It is the BB sectional equivalent view of the turbine housing of 1st embodiment of this 2nd invention of FIG. FIG. 4 is a cross-sectional view corresponding to a DD line in FIG. 3 of the turbine housing according to the first embodiment of the second invention. It is the BB sectional equivalent view of the turbine housing of 2nd embodiment of this 2nd invention of FIG. FIG. 4 is a cross-sectional view corresponding to the line DD in FIG. 3 of the turbine housing according to the second embodiment of the second invention. FIG. 13 is a cross-sectional view corresponding to the line BB in FIG. 2 for describing a modification of the turbine housing illustrated in FIG. 12. It is the BB sectional equivalent view of the turbine housing of 3rd embodiment of this 2nd invention of FIG. It is the BB sectional equivalent view of the turbine housing of 4th embodiment of this 2nd invention of FIG. It is the EE sectional view equivalent figure of the turbine housing of 4th embodiment of this 2nd invention of FIG.

Explanation of symbols

1, 101, 201, 301, 401, 501 Turbine housing 1a Turbine wheel 1b Turbine blade 1c Leading edge portion 1d Shroud portion 10, 110, 210, 310, 410, 510 Inner housing 11 First inner housing member 12 Second inner housing Member 20 outer housing 21 first outer housing member 22 second outer housing member 30, 40, 50 flange portion 60 shroud member

Claims (6)

In a turbine housing comprising an inner housing and an outer housing covering the inner housing,
Providing a shroud member for surrounding the shroud portion of the turbine wheel;
A gap is formed by the shroud member and the outlet side end of the outer housing, and the outlet side end of the inner housing is inserted into the gap,
A turbine housing characterized in that the gap is closed to the outlet side of the turbine wheel and opened to the upstream side of the turbine wheel.   The turbine housing according to claim 1, wherein an outlet side end portion of the inner housing is slidably inserted into the gap. A fitting portion is provided in which the inner housing and the outer housing are slidably fitted to each other at their outlet side end portions,
3. The fitting portion according to claim 1, wherein a thick portion that protrudes toward the outer housing and slidably contacts the outer housing is provided at an outlet side end of the inner housing. The turbine housing as described.   The turbine housing according to claim 1, wherein the shroud member is made of a pipe material.   The turbine housing according to claim 1, wherein the inner housing and the outer housing are made of sheet metal.   The turbine housing according to claim 1, wherein the inner housing is made of cast metal, and the outer housing is made of sheet metal.

Images