JPS5915606A - Variable displacement type radial turbine device - Google Patents

Abstract

PURPOSE:To improve sealing quality of an exhaust pipe flange part, by air- tightly fitting a supporting cylinder of a control rod, which adjusts sectional area of a scroll shaped passage in a radial turbine, to be extended through a turbine housing and an exhaust pipe flange. CONSTITUTION:A cylindrical bush and a control rod 7 transversely located in the axial direction of a scroll shaped passage 5 are provided to a terimal part 5A of the passage 5 in a turbine housing 1, and the rod 7 is displaced then opening area of the terminal part 5A is changed. The bush 6 is extended through a flange part 12A of an exhaust pipe 12 and the housing 1, and air-tightly fitted. The flange part 12A is formed to size and shape in a level containing a penetrative location of the bush 6, and area of a joint part between the housing 1 and the flange part 12A is increased to fully ensure sealing quality. While internal diameters of an outlet passage part 11 and the exhaust pipe 12 are increased, and exhaust resistance and a pressure drop are reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a variable displacement radial turbine device that rotates in such a way that the capacity of the turbine can be changed in accordance with the overall operating conditions.

For example, in radial turbines used in turbochargers for automobile internal combustion engines, which vary the flow rate of gas flowing into the turbine over a wide operating range, good turbine efficiency can be achieved at all times. It's difficult and therefore also. It is designed to achieve maximum efficiency under certain conditions (design point), but if we take the example of a turbocharger, in an operating range that deviates significantly from the design point, there will be excess or deficiency in boost pressure. Therefore, it was necessary to provide some kind of boost pressure control means in consideration of the turbine capacity.

In response, the present applicant has proposed a complete variable displacement radial turbine device that can maintain good turbine efficiency over a wide operating range and control boost pressure by making the turbine capacity or flow characteristics variable. are doing(
Patent Application No. 56-91526, etc.].

To explain this, as shown in FIG. 1, the turbine housing 1 includes an introduction passage 3 whose cross-sectional area gradually decreases from the exhaust inlet to the throat 2.

A scroll-shaped passage 5 surrounding the turbine wheel 4 following this introduction passage 3? Also provided with a scroll-like passage 5
The open space facing the outer periphery of the turbine wheel 4 is formed so as to gradually shrink until it reaches the inside (tongue) of the throat 2. In this device, the space at the end of the scroll-shaped passage 5 is Seven control rods are supported via cylindrical bushings 6 so as to cross in the axial direction of part SAi.
The opening area of the tail portion 5A is changed by the displacement.

A notch 8 is formed at the tip of the control rod 7 in accordance with the cross-sectional shape of the one-passage floor tail portion 5A, and the rod 7 is rotated to adjust the actual opening area of the tail portion 5A.

Generally, the capacity of a turbine is the cross-sectional area A of the throat 2.

It is expressed as a ratio to the distance R from the center of the turbine shaft to the center of gravity of the throat cross section, and the larger the value of A/R, the higher the capacity.
Although it is a large flow type, as the opening area becomes smaller, the flow rate of the gas recirculated around the turbine wheel 4 decreases, and the flow rate to the turbine wheel 4 increases accordingly. Virtually A/R due to movement
The same effect as changing k is produced.

Therefore, as a means for fully rotating the control door, for example, the second
By providing a diaphragm device @10 as shown in the figure and controlling the rotation th of the control rod 7 based on the controlled negative pressure such as the differential pressure between the engine suction negative pressure and the exhaust pressure, a relatively wide range of operation can be achieved. This makes it possible to maintain high turbine efficiency over the entire range and control boost pressure to an appropriate value.

Note that instead of forming the notch 8, the control rod 7' (f
- 1 passage floor tail part 5A supported so as to be displaceable in the axial direction;
There is also one in which the opening area changes depending on how much the rod 7 enters.

Incidentally, in such a variable displacement radial turbine device, the control rod 7 and the cylindrical bushing 6 that fully supports the control rod 7 are placed from the exhaust outlet side of the turbine housing 1 and in close proximity to the outlet passage portion 11 (FIG. 1). Because it will be a structure that will be installed in the position.

There was a problem in that the mounting 7 flange surface of the exhaust pipe 12 connected to the housing 1 became very narrow near the insertion part of the bushing 6, and the sealing performance deteriorated due to this. In addition, for the same reason, it is difficult to fully open the entire inner diameter of the outlet passage section 11 and the exhaust pipe 12.

It is also disadvantageous in terms of low exhaust pressure.

The present invention was made with attention to such problems.
, a cylindrical bush that supports the control rod.

By passing the flange part of the exhaust pipe connected to the turbine housing through the shell and fitting it airtightly into both the seventh rank part and the turbine housing.

The above conventional problems are solved.

The present invention will be explained below based on illustrated embodiments.
Components that are substantially the same as those in the figures or FIG. 2 will be described with the same reference numerals.

In the present invention, as shown in FIG.
However, due to this configuration, the 7-rank portion 1
2A? ]l'' Button 60 must be formed in such a size and shape as to include the penetration portion, and as a result, the housing 1
The area of the joint between the and the seventh rank portion 12A is increased, and therefore sufficient sealing performance is ensured.

In addition, since the cylindrical pusher T+-6 is airtightly fitted into the housing l and the seventh rank part 12A by a method such as tight fitting, it is possible to prevent gas leakage between the above-mentioned parts, and the outlet passage It is possible to increase the inner diameter of the section 11 and the exhaust pipe 12 to the extent that a part of the bushing 6 is exposed on the passage wall as shown in the figure.
Performance can be improved by reducing exhaust resistance or pressure loss when the load is high and the exhaust flow rate is large.

In this embodiment, a part of the control iron door is made small in diameter to reduce the contact area with the bushing 6, thereby reducing the frictional resistance when rotating the Shirorad 7. By introducing air from, for example, a compressor (not shown) into the tubular space 13 created between the rod 7 and the bushing 6, the rod 7 and the bushing 6 can be cooled to reduce the thermal burden. .

FIG. 4 shows another embodiment of the invention, in which a diaphragm device lO
The present invention relates to a variable capacity mechanism in which the rod 7 is connected in series with the control rod 7 to drive the rod 7 in the axial direction, and the flow rate is controlled in accordance with the entry fK of the rod 7 into the scroll-like passage tail portion 5AK. is applied. Since the other points are the same as those in FIG. 3, the same parts are given the same reference numerals and the explanation will be omitted.

As described above, according to the present invention, in the radial turbine device in which the cross-sectional area of the passage at the tail end of the scroll-like passage is adjusted based on the displacement of the control rod in the rotational direction or the axial direction, the control rod is displaceably supported. Since the cylindrical bushing passes through the turbine housing and the plunge part of the exhaust pipe connected to it and is fitted airtight, the joint area between the turbine housing and the exhaust pipe flange is expanded. The sealing performance is improved, and the internal diameter of the exhaust outlet portion of the housing and the exhaust pipe is ensured as large as possible to reduce exhaust resistance.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view of a conventional example, and FIG. 2 is a view taken along arrow B in FIG. FIG. 3 is a longitudinal sectional view of one embodiment of the present invention, and FIG. 4 is a longitudinal sectional view of another embodiment. DESCRIPTION OF SYMBOLS 1... Turbine housing, 4... Turbine wheel, 5... Scroll-shaped m path, sA... Tail part of scroll-shaped passage, 6... Cylindrical bush, 7... Control rod 512. ... Exhaust [, 12A... Flange part of exhaust pipe. Patent applicant Nissan Motor Co., Ltd. Figure 1 Figure 2

Claims (1)

What is claimed is: A control rond located across the tail of a scroll-like passage surrounding a turbine wheel. In the radial turbine device, the radial turbine device is displaceably supported via a cylindrical bushing fitted in a substantially axial direction of the turbine housing, and the entire passage cross-sectional area of the scroll-shaped passage tail portion is adjusted based on the displacement of the control rod. Pass the bushing through the flange of the exhaust pipe that connects to the turbine housing. A variable displacement radial turbine device, characterized in that the flange portion and the turbine housing are fitted in an airtight manner.