JP7244193B2 - Casting core for water-cooled turbine housing of exhaust turbocharger - Google Patents

Description

The present invention relates to a casting core for a water-cooled turbine housing of an exhaust turbocharger.

In an exhaust turbocharger, a turbine housing in which turbine blades are arranged is exposed to high-temperature exhaust gas. Therefore, in order to suppress heat damage to the turbine housing, it has been proposed to provide a cooling water jacket in the turbine housing to make it water-cooled. If the turbine housing is provided with a cooling water jacket as in Patent Document 1, the turbine housing can be made of aluminum to reduce the weight of the turbine housing, which can contribute to an improvement in fuel efficiency.

JP 2018-173058 A

Now, the housing that makes up the exhaust turbocharger is manufactured by casting because it has a hollow inside. will be formed using the child.

In this case, since the outlet-side cooling water jacket that covers the exhaust gas outlet has a substantially cylindrical portion, in manufacturing the core for this outlet-side cooling water jacket, molding that relatively moves in the axial direction of the core is required. A mold is used for manufacturing, and in this case, when removing the mold, the pair of molds are separated from each other, and then the core is pushed out from one of the molds with an ejector pin.

However, since the groove width of the outlet-side cooling water jacket is not large, the thickness of the cylindrical portion of the core must be considerably thin. A collapse phenomenon was observed. Since the shape of the core appears as the shape of the outlet-side cooling water jacket, if part of the core is crushed, part of the outlet-side cooling water jacket becomes distorted, which adversely affects the flow of cooling water. or the wall thickness may deviate from the allowable range of the design, causing a problem in terms of strength.

The present invention has been made against the background of such a situation, and by improving the core, it is possible to manufacture a water-cooled turbine housing with high yield and high precision, and the turbine housing as a product is also improved. This is intended to improve cooling efficiency and increase rigidity.

The present invention relates to a core, and the core is
When casting a turbine housing configured such that it has an exhaust gas outlet opening in the direction of the rotation axis of the turbine blade, and an outlet-side cooling water jacket is formed in a meat portion surrounding the exhaust gas outlet. is intended to use
"It is manufactured using a mold that moves relative to the axial direction,
At least one of the inner peripheral surface and the outer peripheral surface is provided with reinforcing ribs for increasing the contact area of the ejector pins when they are molded by the mold and then ejected axially from one of the molds by the ejector pins. , are formed in a large number spaced apart in the circumferential direction.”
It has the characteristics of

When reinforcing ribs are formed on the outer peripheral surface of the core as in the present invention , the reinforcing ribs on the outer periphery appear as grooves in the outlet cooling water jacket of the turbine housing . Ribs appear on the inner circumference of the gas outlet or on the outer circumference of the turbine housing.

When the core is manufactured using the molding die and then ejected using the ejector pin, by providing the core with reinforcing ribs as in the present invention , the contact between the core and the ejector pin is reduced. The contact area is increased, and even if the core is thin, it can be pushed out without causing a crushing phenomenon. Therefore, the core can be manufactured with high precision, which contributes to improving the precision of the turbine housing as a product, and also contributes to cost reduction by increasing the yield.

Furthermore, since the reinforcement rib appears as a concave groove in the outlet-side cooling water jacket of the turbine housing , the turbine housing can increase the capacity of the outlet-side cooling water jacket to improve the cooling efficiency. In addition, since a group of ribs is formed on the inner peripheral surface of the exhaust gas outlet or the outer peripheral surface of the turbine housing by making the wall thickness equal, the reinforcing effect of the ribs contributes to the improvement of the rigidity of the turbine housing.

It is a figure which shows the housing which concerns on embodiment, and is the figure seen from the discharge direction of exhaust gas, and the other side. FIG. 2 is a sectional view taken along the line II-II in FIG. 1; FIG. 2 is a sectional view taken along line III-III in FIG. 1; FIG. 3 is a sectional view taken along line IV-IV of FIG. 2; It is a perspective view of a core. It is a figure which shows the molding state of a core, (A) is the figure seen from the die-cutting direction, (B) is a BB sectional view of (A).

(1). Turbine Housing Structure Next, an embodiment of the present invention will be described with reference to the drawings. First, the turbine housing will be described with reference to FIGS. 1-4.

An exhaust turbocharger has a turbine housing with turbine blades, a compressor housing with compressor blades, and a bearing housing (center housing) that holds a rotating shaft. 1 is integrated with the bearing housing 2 as shown in FIGS. 2 and 3, the oil drain hole 3 can be seen in the lower part of the bearing housing 2. As shown in FIG. Note that the compressor housing is fixed to the bearing housing 2 .

As shown in FIGS. 2 and 3, the turbine housing 1 includes a turbine chamber 4 in which turbine blades are rotatably arranged, a turbine scroll chamber 5 communicating with the turbine scroll chamber 5 from the outer peripheral side, and turbine blades communicating with the turbine chamber 4 . and an exhaust gas outlet 6 opening in the direction of the rotation axis O of the. The exhaust gas outlet 6 has a larger outer diameter than the turbine chamber 4 . An exhaust system member such as a catalyst case is connected to the exhaust gas outlet 6 .

The turbine housing 1 of this embodiment is of a top winding type in which the exhaust gas flows into the scroll chamber 5 from below, rotates upward, and is discharged from the exhaust gas outlet 6 . In FIGS. 2 and 3, only the upper portion of the turbine scroll chamber 5 is shown, but this is because FIGS. 5 is formed over substantially the entire circumference while reducing the cross-sectional area from the start end to the end end. The start end of the turbine scroll chamber 5 is located generally below the turbine chamber 4, and communicates with the start end of the exhaust gas introduction passage 7, only the inlet of which is shown in FIGS.

Therefore, the turbine housing 1 has a main body 8 having a turbine chamber 4, a turbine scroll chamber 5, and an exhaust gas outlet 6, and an exhaust gas introduction cylindrical portion 9 having an exhaust gas introduction passage 7 formed therein. An upper flange 10 for fixing to the cylinder head is formed at the tip of the exhaust gas introduction tube portion 9 . The exhaust gas introduction tube portion 9 is tilted backward so as to approach the cylinder head as it goes downward.

As shown in FIGS. 1 to 3, a waste gate passage 11 communicating with the exhaust gas introduction passage 7 and the exhaust gas outlet 6 is formed in the upper portion of the main body 8 . The exit of the wastegate passage 11 is opened and closed by a wastegate valve (not shown). Therefore, the main body 8 is provided with a shaft supporting hole 12 into which the rotating shaft of the waste gate valve is fitted.

(2) Cooling Means As shown in FIGS. 2 and 3, inside the turbine housing 1, there are an inside jacket 13 positioned on the side of the bearing housing 2 as a jacket through which cooling water passes, and an inside jacket 13 positioned on the side of the exhaust gas outlet 6. A positioned outside jacket 14 is formed.

The inside jacket 13 is formed so as to generally surround the turbine scroll chamber 5 from the outer peripheral side and the bearing housing 2 side, and the tip thereof extends to the tip surface of the exhaust gas introduction tube portion 9 . On the other hand, the outside jacket 14 has a first portion 14a surrounding the turbine chamber 4, a second portion 14b surrounding the exhaust gas outlet 6, and a third portion 14c passing through the exhaust gas introduction tubular portion 9, The tip of the third portion 14c is opened to the tip surface of the exhaust gas introduction tubular portion 9, similarly to the inside jacket 13. As shown in FIG.

The inside jacket 13 and the outside jacket 14 are completely communicated at their lower and upper ends, but it is possible to communicate at a portion between the upper and lower ends. As shown in FIG. 1, the upper end of the main body 8 is formed with an outlet boss portion 15 that opens the cooling water outlet port upward, while the lower end portion of the exhaust gas introduction cylinder portion 9 is formed with a An inlet boss portion 16 is formed to open the cooling water inlet port downward.

The second portion 14b of the outside jacket 14 corresponds to the outlet side cooling water jacket described in the claims, and as shown in FIG. A large number of long grooves 17 are intermittently formed at appropriate intervals in the circumferential direction. Further, the width of the second portion 14b is reduced from a portion continuous with the first portion 14a toward the tip.

The concave groove 17 is formed on the inner peripheral surface and the outer peripheral surface of the second portion 14b, and when the extended lines of the arcuate surfaces are connected, they form a perfect circle. Since the grooves 17 are formed on the inner peripheral surface of the second portion 14b and the thickness of the inner wall of the second portion 14b is made the same, the inner peripheral surface of the exhaust gas outlet 6 has corresponding grooves 17. An inwardly directed rib 18 is formed. Outward ribs corresponding to the concave grooves 17 may be formed on the outer peripheral surface of the cylindrical portion forming the exhaust gas outlet 6 .

2 is a cross-sectional view of a portion where the bearing housing 2 and the groove 17 do not exist, and FIG. 3 is a cross-sectional view of a portion where the bearing housing 2 and the groove 17 are present. 3 is larger than 2, the presence of the groove 17 can be understood.

Forming the group of recessed grooves 17 in the second portion 14b of the outside jacket 14 as in the embodiment increases the volume and surface area, so that the cooling performance for the exhaust gas outlet 6 can be improved. In addition, since the group of inward ribs 18 are arranged on the inner peripheral surface of the exhaust gas outlet 6, the turbine housing 1 can be improved in rigidity without increasing its weight. Also, although the exhaust gas outlet 6 is exposed to the exhaust gas and becomes hot, the presence of the inward ribs 18 increases the surface area, thereby promoting heat exchange with the cooling water and improving the cooling performance.

(3) Manufacture of Turbine Housing and Core The turbine housing 1 is a cast product made of aluminum, and the hollow portion is formed by a core. Therefore, in manufacturing the turbine housing 1 of the present embodiment, it is necessary to manufacture a core having the same shape as the inside jacket 13 and a core having the same shape as the outside jacket 14 .

The core 19 for forming the outside jacket 14 is shown in FIG. It has a cylindrical portion 19b corresponding to the second portion 14b and an extension portion 19c corresponding to the third portion 14c of the outside jacket 14, and the ring-shaped portion 19a forms half of the cooling water outlet port. A projection 19d is formed for this purpose.

The cylindrical portion 19b is not continuous over the entire circumference, and a U-shaped side notch 20 is formed at a portion corresponding to the shaft support hole 12 of the turbine housing 1 to reach the ring-shaped portion 19a. there is The portion of the notch 20 is a meat portion of the turbine housing 1, and the shaft support hole 12 is opened in this meat portion by drilling.

In addition, a lower notch 21 cut to the middle height is formed in the portion where the projection 19d is provided. Therefore, at the location of the lower notch 21, the lower portion of the exhaust gas outlet 6 is thickened to maintain high strength.

In the cylindrical portion 19b of the core 19, a large number of reinforcing ribs 22 extending in the axial direction are intermittently formed on the inner peripheral surface and the outer peripheral surface corresponding to the grooves 17 described above. It is As with the concave groove 17, it is set to form a perfect circle when the extension lines of the inner and outer reinforcing ribs 22 are connected.

Core 19 is manufactured using a molding apparatus partially shown in FIG. That is, the molding device is composed of a pair of molding dies (molds) that are in close contact with each other and separate from each other in the axial direction of the tubular portion 19b. 23a, and a cavity portion 23b for molding the tip end surface and the outer peripheral portion of the tubular portion 19b. The core 19 is pushed out by a large number of ejection pins 24 provided on the molding die 23 of FIG.

In the present embodiment, since the group of reinforcing ribs 22 is formed inside and outside the cylindrical portion 19b, the ejector pin 24, even though it is circular, has an outer diameter as large as possible so that it does not protrude from the cylindrical portion 19b. Installation area can be increased. Therefore, the core 19 is pushed while preventing the cylindrical portion 19b from collapsing. As a result, the core 19 can be manufactured with high accuracy and high yield without increasing the thickness of the cylindrical portion 19b as a whole.

By providing the core 19 with the reinforcing ribs 22, the grooves 17 are formed in the second portion 14b of the turbine housing 1. It is already known that the grooves 17 improve the cooling effect and the rigidity. As mentioned above.

Although the embodiments of the present invention have been described above, the present invention can be embodied in various other ways. For example, the shape of the core (in other words, the shape of the outlet-side cooling water jacket) can be embodied in various ways. Also, the turbine housing does not necessarily have to be integrated with the bearing housing.

The present invention can be embodied in a turbine housing for an exhaust gas turbocharger and cores used in its manufacture. Therefore, it can be used industrially.

1 Turbine housing 2 Bearing housing 4 Turbine chamber 5 Turbine scroll chamber 6 Exhaust gas outlet 7 Exhaust gas introduction passage 8 Main body 9 Exhaust gas introduction cylindrical portion 11 Waste gate passage 13 Inside jacket 14 Outside jacket 14b Exit side cooling water Second portion corresponding to jacket 15 Outlet boss 16 Inlet boss 17 Groove 18 Inward rib 19 Core 19a Ring-shaped part 19b Cylindrical part 22 Reinforcing rib 23 Mold (mold)
24 ejection pin

Claims (1)

When casting a turbine housing having an exhaust gas outlet opening in the rotation axis direction of the turbine blade, and an outlet-side cooling water jacket formed in a meat portion surrounding the exhaust gas outlet, the outlet A core used to form a side cooling water jacket,
It is manufactured using a mold that moves relative to the axial direction,
At least one of the inner peripheral surface and the outer peripheral surface is provided with reinforcing ribs for increasing the contact area of the ejector pins when they are molded by the mold and then ejected axially from one of the molds by the ejector pins. , are formed in a large number spaced apart in the circumferential direction,
Casting core for water-cooled turbine housing of exhaust turbocharger.

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