JP6754658B2 - How to manufacture a turbine for an exhaust turbocharger - Google Patents

Description

The present invention relates to a manufacturing method of the turbine to be used in an exhaust turbocharger provided in an internal combustion engine such as automobile.

The exhaust turbocharger rotates a compressor by a turbine driven by exhaust gas, and the turbine and the compressor are connected by a rotating shaft. As a means for fixing the turbine and the rotating shaft, a type in which one end of the rotating shaft is forcibly fitted into a hole formed in the turbine is generally used. However, in Patent Document 1, the turbine is bolted or bolted to the rotating shaft. A structure that appears to be fastened with nuts is disclosed. On the other hand, in the conventional forced fitting method, the turbine has a bag hole opened only at one end, and one end of the rotating shaft is forcibly fitted into the bag hole.

Special Publication No. 58-49691

Patent Document 1 is presumed to be a screwing method, but the screwing method may cause a problem that it takes time to assemble and may cause looseness. On the other hand, the forced fitting method has an advantage that it can be assembled in a short time and does not loosen, and therefore, the forced fitting method is generalized.

Now, the rotational torque of the turbine is controlled by the waistgate valve, and in order to improve the responsiveness of the control (that is, the responsiveness of supercharging), it is preferable that the inertial force of the turbine rotation is as small as possible, and for that purpose. , The turbine should be as light as possible. In addition, since the turbine is exposed to exhaust gas and becomes hot, heat dissipation should be as good as possible.

However, regardless of whether it is a screw type or a forced fitting method, it cannot be said that the conventional type is considered for weight reduction and heat dissipation, and it can be said that there is still room for improvement.

The present invention has been made to improve such a situation.

The present invention relates to a method for manufacturing a turbine used for an exhaust turbocharger, and the turbine is manufactured in a state where center holes opened at both ends thereof are formed, and one end of a rotating shaft is provided in a used state. Is forcibly fitted into the center hole.
Wherein after manufacturing the main hole casting or die-casting an intermediate product of the blocked up by one of the lid, is characterized in that to open at both ends the center hole by removing the lid.

The turbine of the present invention is a system in which the rotating shafts are forcibly fitted, and since the center holes are opened at both ends, the weight of the turbine can be reduced and the rotational inertia force can be reduced. Therefore, the responsiveness of supercharging control of the waistgate valve can be improved. Therefore, when applied to automobiles, drivability can be improved.

Further, since the center hole is opened toward the exhaust gas discharge direction, the heat dissipation area of the turbine can be increased as compared with the conventional case, and as a result, the heat dissipation property can be improved and the durability can be improved. Further, when the rotating shaft is forcibly fitted, if air accumulates inside the turbine, this acts as a reaction force on the rotating shaft. However, in the present invention, the air does not accumulate inside the turbine, so the rotating shaft is forcibly fitted. You can do it well.

By the way, since the turbine has a complicated shape, it is often cast using a special alloy. In this casting, in order to maintain high quality, it is required that the metal hot water flows evenly into the empty space of the mold. However, in the present invention, by pouring the metal hot water into the mold from the lid portion, the metal hot water can be poured into each part of the empty space of the mold at the same speed, so that problems such as casting defects do not occur. , High quality can be ensured.

Then, when the lid is removed from the intermediate product, the central hole opens at both ends, so that the above-mentioned effect can be enjoyed. Therefore, according to the present invention , it is possible to easily manufacture a turbine having excellent quality and weight reduction.

(A) is a vertical sectional front view of a main part of an exhaust turbocharger using a turbine manufactured according to the embodiment , (B) is a side view of the turbine, and (C) is a front view of the turbine. (A) is a front view of the separated longitudinal section of the turbine housing and the rotating shaft, and (B) and (C) are views showing intermediate products in the turbine manufacturing process.

Next, an embodiment of the present invention will be described with reference to the drawings. In the present embodiment, the front-back / left-right wording is used to clarify the direction, and the longitudinal direction of the rotation axis is the left-right direction and the horizontal direction orthogonal to the longitudinal direction is the front-back direction.

As shown in FIGS. 1 (A) and 2 (A), the exhaust turbocharger includes a blade-type turbine 1, and one end of a rotating shaft 2 is fixed to the turbine 1 by forced fitting. ing. A compressor is fixed to the other end of the rotating shaft 2, but this is omitted.

The turbine 1 is arranged in the turbine chamber 4 formed in the turbine housing 3, while the rotating shaft 2 is rotatably held by the bearing portion 6 formed in the intermediate housing 5 via the floating metal 7. ing. In the present embodiment, the turbine housing 3 and the intermediate housing 5 are integrally manufactured by casting aluminum. At the end of the intermediate housing 5 opposite to the turbine housing 3, the compressor housing 8 shown only partially in FIG. 1 (A) is fitted through a C-shaped stopper ring 9 so as not to be pulled out.

The turbine housing 3 is formed with a turbine-side scroll space 10 communicating with the outer peripheral portion of the turbine chamber 4, and cooling water jackets 11 are formed on both left and right sides of the turbine-side scroll space 10. An oil inlet 12 penetrating in the vertical direction is formed on the upper portion of the bearing portion 6. Further, a hollow oil outlet space 13 is formed below the bearing portion 6. Further, cavities 14 are formed on both the left and right sides of the bearing portion 6, and the cavities 14 communicate with the oil outlet space 13.

A first metal oil seal 15 is fixed to the end of the bearing portion 6 on the side of the compressor housing 8. The cross-sectional display (hatching) of the first oil seal 15 is omitted. Further, the left end portion of the intermediate housing 5 has a large opening, and the retainer ring 16 is fixed to this large-diameter opening, and the second oil seal 15 is between the retainer ring 16 and the first oil seal 15. 17 is intervening. The second oil seal 17 is fixed to the first oil seal 15.

Of the rotating shaft 2, the portion near one end fitted in the through hole (inner peripheral hole) 3a of the turbine housing 3 has a larger diameter than the portion fitted in the floating metal 7, and the large diameter portion has a larger diameter. A plurality of annular grooves 18 are formed, and an oil seal 19 is attached to the annular grooves 18.

The exhaust gas flows into the scroll space 10 on the turbine side from the circumferential direction, performs the work of rotationally driving the turbine 1, and then is discharged in the axial direction. Therefore, the exhaust outlet 20 communicating with the turbine chamber 4 is opened in the turbine housing 3 in the axial direction.

In the present embodiment, since the turbine housing 3 and the intermediate housing 5 are integrated, the rotary shaft 2 and the turbine 1 need to be fitted into the turbine chamber 4 from the exhaust outlet 20 side. Therefore, the outer circumference of the turbine chamber 4 is formed in a straight shape, and the ridge line of the blade 21 constituting the turbine 1 also has a portion parallel to the axis line in the front surface.

The turbine 1 is provided with a straight center hole 22 that opens at one end and the other end, and one end 2a of the rotating shaft 2 is forcibly fitted into the end of the center hole 22 by shrink fitting or the like. It is fixed together. Therefore, the weight of the turbine 1 can be reduced to improve the responsiveness of supercharging control, and the heat dissipation can be improved by increasing the surface area.

Turbine 1 is a cast product using a metal such as alloy steel, and as shown in FIGS. 2 (B) and 2 (C), after casting the intermediate product 24 in a state where the other end is closed by the lid 23. , The lid 23 is cut by cutting to form a product. In this case, in the example of FIG. 2B, the lid 23 is formed in a continuous bottomed tubular shape on the other end surface of the turbine 1, and the lid 23 is removed by milling or lathe processing. Therefore, the other end surface of the turbine 1 is also finished at the same time. On the other hand, in the example shown in FIG. 2C, the lid 23 is formed in a state of a plug having a part thereof inside the turbine 1, and is cut off by a drill 25. Therefore, in FIG. 2C, the lid 23 can be cut and the center hole 22 can be accurately adjusted at the same time.

In any case, since the lid 23 closes the center hole 22, the metal hot water flows evenly into the mold through the portion of the lid 23 during casting. Therefore, the turbine 1 can be manufactured with high accuracy and the quality can be stabilized. That is, since the portion of the lid 23 functions as a distribution port for evenly flowing the metal hot water, the turbine 1 can be manufactured with high accuracy and stability.

In the above embodiment, the turbine housing and the intermediate housing are integrated, but the present invention can also be applied to a type in which the turbine housing and the intermediate housing are separate bodies. Therefore, the blades constituting the turbine 1 can adopt various shapes. Further, although the central hole 22 of the embodiment is a straight hole, it is also possible to form the central hole into a different diameter hole having different inner diameter portions.

The invention of the present application can be actually embodied in an exhaust turbocharger. Therefore, it can be used industrially.

1 Turbine 2 Rotating shaft 3 Turbine housing 4 Turbine chamber 5 Intermediate housing 6 Bearing part 10 Turbine side scroll space 14 Exhaust outlet 22 Center hole 23 Intermediate lid 24 Intermediate

Claims (1)

It is a manufacturing method of the turbine used for the exhaust turbocharger.
The turbine is manufactured in a state of empty center hole which is open at both ends, in the configuration in which one end of the rotating shaft in the use state is forcibly fitted into the center hole,
An intermediate product in which the center hole is closed by one lid is manufactured by casting or die casting, and then the lid is removed to open the center hole at both ends.
How to manufacture a turbine for an exhaust turbocharger .

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