JP2019148224A - Exhaust turbosupercharger - Google Patents

Abstract

To accurately form a turbine scroll chamber while securing the easiness of the attachment of a turbine blade, in an exhaust turbosupercharger in which a turbine housing and a bearing housing are integrated with each other.SOLUTION: A turbine housing 4 and a bearing housing 6 are manufactured as an integrated product by aluminum-forging. A shroud 7a of the turbine housing 4 is regulated even by an end face of a shroud piece 32 being a different member different from the turbine housing 4. An external peripheral part of a turbine blade 1 intrudes into a shroud part 7a, however, since the shroud piece 32 is of a post-attachment type, the turbine blade 1 can be attached without trouble. The shroud piece 32 and an exhaust outlet port 8 have a fitting part 34 located on the turbine blade 1 side, and a screw part 35 located behind the fitting part. The screw part 35 functions as a male screw at the shroud piece 32, and functions as a female screw at the exhaust outlet port 8.SELECTED DRAWING: Figure 6

Description

  The present invention relates to an exhaust turbocharger used for an internal combustion engine.

  In the exhaust turbocharger, the turbine housing in which the turbine blades are arranged is exposed to high-temperature exhaust gas. For this reason, the turbine housing is often made of special steel, but there is a problem of increased weight and cost. Therefore, in order to ensure heat resistance while reducing the weight, it has been proposed that the turbine housing be made of a light alloy such as aluminum and provided with a cooling water jacket to be water-cooled, and an example thereof is disclosed in Patent Document 1. ing.

  The exhaust turbocharger includes a turbine housing in which turbine blades are disposed, a compressor housing in which compressor blades are disposed, and a bearing housing (center housing) that is positioned between the two and rotatably holds a rotating shaft. However, in Patent Document 1, these three housings are integrally cast with aluminum to form a cooling water jacket in each housing.

International Publication No. WO2014 / 103570

  In the turbine housing, a turbine scroll chamber through which exhaust gas flows is formed outside the turbine blades, and an exhaust outlet hole opened in the direction of the rotation axis of the turbine blades is formed. The inflowing exhaust gas flows in the circumferential direction along the turbine scroll chamber and flows out to the exhaust outlet hole while driving the turbine blades.

  Therefore, the turbine blade has a substantially trapezoidal shape when viewed from the direction orthogonal to the rotation axis, and a shroud that is a connecting portion between the turbine scroll chamber and the exhaust outlet hole is provided outside the outer peripheral portion of the turbine blade. A small gap is formed between the turbine blade and the shroud portion to avoid interference between the turbine blade and the shroud portion. Precisely, the outer periphery of the turbine blade enters the shroud portion of the turbine housing, and interference between the turbine blade and the shroud portion is caused between the portion of the shroud portion of the turbine housing close to the exhaust outlet hole and the turbine blade. There is a slight gap to avoid (setting the gap between the turbine blade and the shroud to an appropriate value is very important for ensuring the performance of the exhaust turbocharger).

  Accordingly, the inner diameter (minimum diameter) of the shroud portion of the turbine housing is smaller than the outer diameter (maximum diameter) of the turbine blade. Due to such characteristics, conventionally, the turbine housing and the bearing housing are configured as separate members, and a turbine scroll chamber is formed between the turbine blades and the bearing housing. In assembling the exhaust turbocharger, After the turbine blades are set, the turbine housing and the bearing housing are fixed.

  On the other hand, in Patent Document 1, the inner diameter (minimum diameter) of the shroud portion of the turbine housing is smaller than the outer diameter (maximum diameter) of the turbine blade. However, when the turbine housing and the bearing housing are integrated, the turbine blade is replaced with the turbine housing. It cannot be fitted in and cannot be manufactured.

  In this regard, it can be said that a shroud piece having a larger diameter (or the same diameter) than the outer diameter of the turbine blade is attached to the exhaust outlet hole of the turbine housing, and the shroud portion of the turbine housing is configured by the shroud piece.

  The present invention has been made on the basis of such knowledge, and by using the shroud piece, it is possible to integrate the turbine housing and the bearing housing. It is intended to improve the dimensional accuracy of the exhaust gas passage.

The exhaust turbocharger of the present invention is
“A turbine housing in which turbine blades are rotatably arranged and a bearing housing that holds a rotating shaft fixed to the turbine blades are integrated.
In the turbine housing, a turbine scroll chamber for driving the turbine blades with exhaust gas is formed so as to surround the turbine blades, and an exhaust outlet hole through which the exhaust gas driving the turbine blades is discharged Is open toward the axial direction of the rotating shaft,
Furthermore, a cylindrical shroud piece is mounted in the exhaust outlet hole in a state in which the tip surface thereof faces the outer peripheral portion of the turbine blade. ''
It is the basic composition.

And in the above basic configuration,
“A threaded portion for screwing the shroud piece into the shroud piece and the exhaust outlet hole and a fitting portion that fits closely at a portion located closer to the turbine blade than the threaded portion are formed. doing"
The structure is added.

  If the shroud piece is press-fit, galling may occur due to slanting. However, in the present invention, since the shroud piece is screwed, it can be accurately attached to the concentric state with the exhaust outlet hole. .

  In the press-fitting type, if the dimensional difference between the outer diameter of the shroud piece and the inner diameter of the exhaust outlet hole is small, the friction is reduced and the mounting strength is reduced. If the difference is large, there is a problem that the shroud piece cannot be press-fitted. For this reason, it is necessary to strictly manage the dimensional accuracy between the outer diameter of the shroud piece and the inner diameter of the exhaust outlet hole. Since the screwing torque can be adjusted arbitrarily, it can be easily attached to a predetermined strength without strictly managing the dimensional accuracy. Therefore, it is possible to reduce the time and effort of managing the manufacturing process and the assembly process.

  Further, since the shroud piece can be easily removed, the shroud piece and the turbine blade can be easily replaced. Alternatively, each exhaust turbocharger can be assembled while being trimmed so that the distance from the turbine blade is appropriate, which can further contribute to accuracy improvement.

It is a figure which shows the housing which concerns on embodiment, (A) is a perspective view, (B) is a bottom view. (A) is a top view of a housing, (B) is a front view. (A) is a right side view, and (B) is a left side view. It is the whole longitudinal front view. It is a principal part enlarged view of FIG. (A) is a longitudinal front view of the state where the shroud piece is separated, and (B) is another example.

(1). Outline Next, an embodiment of the present invention will be described with reference to the drawings. First, an outline will be described with reference to FIGS. In the present embodiment, front / rear, left / right, and upper / lower terms are used to clarify the direction, but the longitudinal direction of the rotation axis is the left / right direction, and the cylinder head H (FIG. (B) or FIG. The direction perpendicular to the exhaust side of A) is defined as the front-rear direction, and the direction facing the cylinder head is the front. The vertical direction is the vertical direction. As a precaution, the directions are clearly shown in FIGS.

  As shown in FIG. 4, the exhaust turbocharger includes a turbine blade 1 having a twisted blade and a compressor blade 2, both of which are fixed to one end and the other end of the horizontal rotation shaft 3. Has been. The exhaust turbocharger has a turbine housing 4 and a compressor housing 5 and a bearing housing (bearing housing) 6 positioned between the two. The turbine housing 4 and the bearing housing 6 are made of aluminum. It is integrally manufactured as a casting product. The compressor housing 5 is an aluminum die-cast product or cast product.

  In the turbine housing 4, a turbine scroll chamber 7 is formed so as to surround the turbine blade 1, and an exhaust outlet hole 8 opened in the direction of the rotational axis of the turbine blade 1 is formed. The turbine scroll chamber 7 has a spiral shape in which the distance from the rotational axis of the turbine blade 1 gradually decreases from the start end to the end, and an inlet opening toward the cylinder head H at the start end (upper end). A passage 9 (see FIG. 4) communicates.

  Accordingly, the turbine housing 4 has a circular portion 4a in which the turbine scroll chamber 7 is formed and an inlet cylinder portion 4b in which the inlet passage 9 is formed, and protrudes on the opposite side to the bearing housing 6. The side projecting portion 4c is formed in a state of being integrally connected to the circular portion 4a and the inlet tube portion 4b. At the rear end of the inlet cylinder portion 4b, an inlet side flange 4d is formed which is fixed to the cylinder head (or a collection portion of the exhaust manifold) with bolts.

  Further, as shown in FIG. 4 (see also FIG. 1B), a wastegate passage 10 branched from the entrance passage 9 opens toward the opposite side of the bearing housing 6, and the wastegate passage 10 and the exhaust gas are exhausted. The outlet hole 8 communicates with the inside of the side protruding portion 4c. For this reason, the side overhang | projection part 4c has a long form up and down.

  The wastegate passage 10 is opened and closed by a wastegate valve (not shown). A valve shaft hole 11 into which a valve shaft for driving the waste gate valve is fitted is formed in the upper end portion of the side projecting portion 4c so as to penetrate vertically. Therefore, the upper part of the inside of the side projecting portion 4c is a waste gate space 12 that allows the waste gate valve to rotate. The wastegate valve is driven by a diaphragm actuator that is fixed to the compressor housing 5 via a bracket.

  An outlet flange 13 is formed on the side projecting portion 4c of the turbine housing 4, and although not shown, a catalyst case is fixed to the outlet flange 13 (an exhaust pipe may be fixed).

  As shown in FIG. 4, the compressor housing 5 is formed with an intake inlet 14 and a compressor scroll chamber 15 located outside the compressor blades 2. The intake air pressurized in the compressor scroll chamber 15 is exhausted. The gas is discharged from the outlet 16 to the intake system. The compressor housing 5 is connected to the bearing housing 6 by bolts 18 via a C-shaped or split ring 17. For this reason, a flange 6 a is formed at the end of the bearing housing 6.

  The bearing housing 6 is formed with a bearing portion 20 that rotatably holds the rotating shaft 3 via a floating metal 19. The bearing housing 6 is formed with an oil supply hole 21 opened upward and an oil discharge hole 22 opened downward. Since the seal structure of the rotating shaft 3 is not related to the present invention, the description thereof is omitted.

  One end of the rotating shaft 3 is formed in a large diameter portion 3 a, and the large diameter portion 3 a is press-fitted into the turbine blade 1. Further, a sealing material 23 (see FIGS. 5 and 6) that is in sliding contact with the bearing portion of the turbine housing 4 is attached to the large diameter portion 3a.

  A cooling water jacket through which cooling water flows is formed in the turbine housing 4. The cooling water jacket includes an inside jacket 25 located on the bearing housing 6 side and an outside jacket 26 located on the exhaust outlet hole 8 side, and both are separated from each other by a center partition wall 27. . The outside jacket 26 has an inner annular portion 26a that surrounds the exhaust outlet hole 8, and the waist gate space 12 is located above the inner annular portion 26a. Therefore, the circumference of the wastegate space 12 is surrounded by the outside jacket 26.

  As shown in FIG. 4, the inside jacket 25 and the outside jacket 26 communicate with each other at the lower end, and cooling water is directed toward the inside jacket 25 and the outside jacket 26 at the lower end of the circular portion 4 a in the turbine housing 4. Is formed so as to open downward. A hose is connected to the inlet port 28 via a joint pipe 29.

  The inside jacket 25 and the outside jacket 26 communicate with each other also at the upper end. Therefore, an outlet port 30 for discharging the cooling water of the inside jacket 25 and the outside jacket 26 is formed upward at the upper end portion of the inlet cylinder portion 4 b in the turbine housing 4. A hose is connected to the outlet port 30 via a joint pipe 31.

  The turbine housing 4 is separated into a left and a right by an inside jacket 25 and an outside jacket 26, but an inner portion and an outer portion separated by the inside jacket 25 and the outside jacket 26 have a plurality of unillustrated portions. Connected by ribs.

(2). Shroud piece The turbine blade 1 has a configuration in which a plurality of blades are provided in the shaft portion. When the turbine blade 1 is formed in a trapezoidal shape in front view, the exhaust gas is driven by the exhaust gas, and the exhaust gas is discharged from the exhaust outlet In order to efficiently drive the turbine blade 1 with exhaust gas, the outer peripheral portion of the turbine blade 1 is a shroud (inner peripheral) portion 7 a of the turbine scroll chamber 7. It must be in a state of being entangled. On the other hand, in the structure in which the turbine housing 4 and the bearing housing 6 are integrated, the turbine blade 1 must be fitted from the portion of the exhaust outlet hole 8.

  Therefore, a shroud piece 32 having an outer diameter larger than the outer diameter of the turbine blade 1 is prepared as a separate member from the turbine housing 4, and the turbine blade 1 is inserted into the exhaust outlet hole 8 and then the shroud piece 32 is attached. Thus, a shroud portion 7a having a predetermined distance from the turbine blade 1 is formed (strictly speaking, the exhaust outlet hole 8 is also composed of the shroud piece 32). The compressor blade 2 is fixed to the other end portion of the rotary shaft 3 with a nut 33.

  As shown in FIGS. 5 and 6, the shroud piece 32 and the exhaust outlet hole 8 are formed in a fitting portion 34 that fits tightly without gap to some extent on the tip side facing the turbine blade 1. A screwing portion 35 is formed at the rear portion. Therefore, the fitting portion 34 is a cylinder in the shroud piece 32 and a hole in the exhaust outlet hole 8. The threaded portion 35 is a male thread in the shroud piece 32 and a female thread in the exhaust outlet hole 8.

  A flange 36 is formed at the rear end of the shroud piece 32, while a stopper surface 37 with which the flange 36 abuts is formed in the exhaust outlet hole 8. The front end of the flange 36 and the stopper surface 37 are formed on a tapered surface having a smaller diameter toward the turbine blade 1, but can also be formed on an end surface orthogonal to the rotational axis. On the rear end surface of the shroud piece 32, a plurality of engagement holes (not shown) for engaging the rotary tool are formed side by side in the circumferential direction.

  The fitting portion 34 is set to have a slightly smaller diameter than the root diameter of the threaded portion 35 (male thread portion) in the shroud piece 32. Therefore, in the shroud piece 32, the fitting portion 34 is stepped with a smaller diameter than the screwing portion 35. The fitting part 34 is formed straight in the example of FIGS. 5 and 6A, and in the example of FIG. 6B, the fitting part 34 has a tapered shape narrowed toward the turbine blade 1 at a slight angle θ. Is formed.

  Thus, since the shroud piece 32 is a screw-in type, there exists an effect described in the effect of invention. In addition, when the shroud piece 32 is configured to be screwed, the male screw of the shroud piece 32 and the female screw of the exhaust outlet hole 8 are screwed together. The fastening force by screwing is such that the follower flank of the male screw contacts the female screw. However, since the follower flank is inclined in a spiral shape, it is possible to generate a higher frictional resistance than a simple press-fitting. Therefore, by screwing with a predetermined torque, it can be firmly fastened without being detached.

  Further, the forward position of the shroud piece 32 is defined by the flange 36 abutting against the stopper portion 37, but the torque required for the flange 36 to abut against the stopper portion 37 is expected, and the torque at which the male screw and the female screw are firmly meshed with each other. By setting to the above, the contact pressure between the male screw of the shroud piece 32 and the female screw of the exhaust outlet hole 8 can ensure a surface pressure necessary to ensure high heat transfer. Thereby, cooling of the shroud piece 32 by cooling water can be ensured.

  When the fitting portion 34 is formed in a tapered shape as shown in FIG. 6 (B), the adhesion of the fitting portion 34 can be strengthened by screwing the shroud piece 32, and the anti-galling can be ensured. Contributes to improved pressure stability.

  In the embodiment, the end of the exhaust outlet hole 8 is located behind the rear end of the shroud piece 32. For this reason, the protruding portion 38 (see FIGS. 4 to 6) surrounded by the inner annular portion 26 a of the outside jacket 26 exists on the shroud piece 32, and the shroud piece 32 is provided by the presence of the protruding portion 38. It is possible to prevent the rear end portion from being exposed to the exhaust gas flowing from the wastegate passage 10. Therefore, there is an advantage that the durability of the shroud piece 32 can be improved.

  The present invention can be embodied in an exhaust turbocharger of an internal combustion engine. Therefore, it can be used industrially.

DESCRIPTION OF SYMBOLS 1 Turbine blade 2 Compressor blade 3 Rotating shaft 4 Turbine housing 4a Circular part 4b Inlet cylinder part 4c Side overhang part 5 Compressor housing 6 Bearing housing 7 Turbine scroll chamber 7a Shroud part 8 Exhaust outlet hole 25 Inside jacket 26 Outside jacket 28 Inlet Port 30 Exit port 32 Shroud piece 34 Fitting part 35 Screw part 36 Flange

Claims (1)

A turbine housing in which turbine blades are rotatably arranged and a bearing housing that holds a rotating shaft fixed to the turbine blades are integrated.
In the turbine housing, a turbine scroll chamber for driving the turbine blades with exhaust gas is formed so as to surround the turbine blades, and an exhaust outlet hole through which the exhaust gas driving the turbine blades is discharged Is open toward the axial direction of the rotating shaft,
Further, a cylindrical shroud piece is attached to the exhaust outlet hole in a state in which a tip surface thereof is opposed to an outer peripheral portion of the turbine blade,
The shroud piece and the exhaust outlet hole are formed with a threaded portion for mounting the shroud piece by screwing, and a fitting portion that fits closely at a portion located closer to the turbine blade than the threaded portion. ing,
Exhaust turbocharger.

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