JPH11229887A - Gas sealing structure of turbocharger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate the risk of deformation of a plate installed on the edge side of a vane even if the plate thermally expands. SOLUTION: In this gas sealing structure, a clearance is provided between an outer peripheral surface of a ring shaped plate 20 installed on the edge side of a vane 7 and a turbine housing 1, and a step portion 20a is formed on an inner peripheral portion of the plate 20. An outer peripheral surface of a cylinder-like ring 25 made of the same material as the plate 20 is contacted with the turbine housing 1, and an end portion of the ring 25 is fit into the step portion 20a of the plate 20. Thus, the gas sealing portion is comprised of a contact portion 22 between the outer peripheral surface of the ring 25 and the turbine housing 1, and a contact portion 23 between the outer peripheral surface of the ring 25 and the plate 20. Alternatively, a clearance is provided between the outer peripheral surface of the ring shaped plate installed on the edge side of the vane and the turbine housing. The inner peripheral surface of the plate is fit into a step portion which extends to a back plate, which is installed at the back side of the turbine wheel and is made of the same material as the plate, and is formed thereon. Thus, the gas sealing portion is comprised of a connecting portion between the inner peripheral surface of the plate and the back plate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a gas seal structure for a turbocharger.

[0002]

2. Description of the Related Art A turbocharger (turbocharger) is used in an internal combustion engine such as a gasoline engine or a diesel engine of a vehicle in order to increase the output without increasing the cylinder capacity or the like due to supercharging. In this turbocharger, a turbine is rotated by exhaust gas, and the compressor is driven by the turbine to perform supercharging. As such a turbocharger, there is known a VG (with a variable nozzle vane) turbocharger in which a vane at an exhaust gas inlet is made movable and a flow passage area is varied in order to effectively use exhaust gas energy. .

FIG. 3 is a sectional view showing the structure of a conventional VG turbocharger, and FIG. 4 is an enlarged view of a portion A in FIG.

[0004] As shown in FIG.
A turbine shaft 3 is rotatably supported inside the bearing via a bearing 2. A turbine wheel 4 is fixed to one end of the turbine shaft 3, and a compressor wheel 5 is fixed to the other end.
Has been fixed. A large number of vanes 7 are arranged in the exhaust gas inlet 6 in the circumferential direction.
Is rotated by the link mechanism 8 so that the flow area of the exhaust gas inlet 6 can be changed.

[0005] As shown in FIG. 4, a ring-shaped plate 10 supported by a plurality of supports 11 is provided on the end face side of the vane 7. There is a slight gap (clearance) between the plate 10 and the end face of the vane 4, and a support is provided so that the gap can be maintained even if the vane 7 thermally expands due to the temperature of the exhaust gas. 11 is the same material as the vane 7. That is, the vane 7 is moved in the axial direction (left-right direction in the figure) depending on the temperature of the exhaust gas.
When thermally expanded, the support 11 is the same as that of the vane 7.
Also, since the plate 10 moves in the axial direction due to thermal expansion, the gap can be maintained.

Further, the outer peripheral surface of the plate 10 is in contact with the turbine housing 1 (contact portion 12), and the contact portion 12 is used as a gas seal portion, so that the exhaust gas flowing from the exhaust gas inlet 6 leaks. Not to be. A back plate 13 is provided on the back side of the turbine wheel 4.

[0007]

However, in the conventional gas seal structure of the turbocharger, there is a difference in thermal expansion between the plate 10 and the turbine housing 1.
Since the rigidity of the turbine housing 1 is higher than that of the plate 10, the plate 10 may be deformed. This is because the plate 10 and the turbine housing 1 have different materials and different temperature distributions.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a gas seal structure for a turbocharger in which a plate provided on an end face side of a vane is not likely to be deformed even when thermally expanded, in view of the above prior art.

[0009]

Means for Solving the Problems A first method for solving the above problems is described below.
In the gas seal structure of the turbocharger of the present invention, a gap is provided between the outer peripheral surface of the ring-shaped plate provided on the end face side of the vane and the turbine housing, and a step is formed on the inner peripheral portion of the plate. The outer peripheral surface of a cylindrical ring made of the same material as the plate is brought into contact with the turbine housing, and the end of the ring is fitted to the step of the plate, so that the outer peripheral surface of the ring and the turbine housing And a contact portion between the outer peripheral surface of the ring and the plate is a gas seal portion.

In a gas seal structure for a turbocharger according to a second aspect of the present invention, a gap is provided between an outer peripheral surface of a ring-shaped plate provided on an end face side of a vane and a turbine housing, and the inside of the plate is provided. The peripheral portion extends to a back plate of the same material as the plate provided on the back side of the turbine wheel, and is fitted to a step formed on the back plate to form a contact portion between the inner peripheral surface of the plate and the back plate. Is a gas seal portion.

[0011]

Embodiments of the present invention will be described below in detail with reference to the drawings. Note that, since the present invention has been devised with respect to the gas seal structure of the turbocharger, the gas seal structure will be described in detail here, and other structures will be the same as those of the related art (FIG. 3). Description and illustration are omitted.

<First Embodiment> FIG. 1A is a sectional view showing a gas seal structure of a VG turbocharger according to a first embodiment of the present invention, in which a lower half is omitted, and FIG. It is a perspective view which extracts and reduces and shows the ring of a gas seal structure part.
FIG. 1A is a diagram corresponding to FIG. 4 of the related art. In FIG. 1, the same parts as those in FIG. 4 are denoted by the same reference numerals.

As shown in FIG. 1, a gap 21 is provided between the outer peripheral surface of a ring-shaped plate 20 provided on the end face side of the vane 7 and the turbine housing 1.

A step 2 is provided on the inner periphery of the plate 20.
0a, the outer peripheral surface of the cylindrical ring 25 is brought into contact with the turbine housing 1, and the end of the ring 25 is fitted into the step 20a of the plate 20. Thus, the contact portion 22 between the outer peripheral surface of the ring 25 and the turbine housing 1 and the outer peripheral surface of the ring 25 and the plate 2
The contact portion 23 with 0 is a gas seal portion.

The ring 25 is made of the same material as the plate 20 so as to have the same coefficient of thermal expansion.
The plate 20 is made of the same material as the conventional plate 10 (see FIG. 4). Also, the step 20 of the plate 20
5A, a gap 26 is provided between the end face of the ring 25 and the plate 20.

Therefore, according to the gas seal structure of the turbocharger according to the first embodiment, since the gap 21 is provided between the outer peripheral surface of the plate 20 and the turbine housing 1, the plate 20 and the turbine housing There is no risk that the plate 20 will be deformed due to the difference in thermal expansion from the plate 20.
The exhaust gas is sealed at contact portions (gas seal portions) 22, 23 between the outer peripheral surface of the ring 25 and the turbine housing 1 and the plate 20. Further, since the plate 20 and the ring 25 have the same coefficient of thermal expansion and the rigidity of the ring 25 is smaller than that of the turbine housing 1, the plate 20 is deformed due to a difference in thermal expansion between the plate 20 and the ring 25. There is no fear.

That is, according to the gas seal structure of the turbocharger according to the first embodiment, the deformation of the plate 20 can be avoided with a slight increase in cost by adding one ring 25.

Further, since the gap 26 is provided between the end face of the ring 25 and the plate 20, the ring 25 prevents the plate 20 from moving in the axial direction (the horizontal direction in the drawing) due to the thermal expansion of the support 11. It does not hinder.

<Second Embodiment> FIG. 2 is a sectional view showing a gas seal structure of a VG turbocharger according to a second embodiment of the present invention with a lower half omitted. FIG. 2 is a diagram corresponding to FIG. In FIG. 2, the same parts as those in FIG. 4 are denoted by the same reference numerals.

As shown in FIG. 2, a gap 35 is provided between the outer peripheral surface of the ring-shaped plate 30 provided on the end face side of the vane 7 and the turbine housing 1.

The inner peripheral portion of the plate 30 extends to a back plate 33 provided on the back side of the turbine wheel 4, and a step portion 33 formed on the back plate 33 is formed.
a. This allows the plate 30
A contact portion 31 between the inner peripheral surface of the back plate 33 and the back plate 33 is a gas seal portion.

The back plate 33 is made of the same material as the plate 30 so as to have the same coefficient of thermal expansion. The plate 30 is a conventional plate 10
(See FIG. 4). Further, a gap 34 is provided between the side surface of the plate 30 and the back plate 33 in the step portion 33 a of the back plate 33.

Therefore, according to the gas seal structure of the turbocharger according to the second embodiment, since the gap 35 is provided between the outer peripheral surface of the plate 30 and the turbine housing 1, the plate 30 and the turbine housing There is no risk that the plate 20 will be deformed due to the difference in thermal expansion from the plate 20.
The exhaust gas is sealed at a contact portion (gas seal portion) 31 between the outer peripheral surface of the plate 30 and the back plate 33. The plate 30 and the back plate 33
Have the same coefficient of thermal expansion, and the rigidity of the back plate 33 is smaller than that of the turbine housing 1. Therefore, there is no possibility that the plate 30 is deformed due to the difference in thermal expansion between the plate 30 and the back plate 33.

That is, according to the gas seal structure of the turbocharger according to the second embodiment, the deformation of the plate 30 is avoided only by processing the back plate and changing the shape of the plate without adding any new parts. In addition, as compared with the first embodiment, the number of parts is smaller, so that assembling is easier.

Further, since the gap 34 is provided between the side surface of the plate 30 and the back plate 33, the back plate 33 is
It does not prevent 0 from moving in the axial direction (left-right direction in the figure).

[0026]

As described above in detail together with the embodiments of the present invention, the gas seal structure of the turbocharger according to the first aspect of the present invention is provided with the outer peripheral surface of the ring-shaped plate provided on the end face side of the vane. A gap is provided between the plate and the turbine housing, and a step is formed on the inner peripheral portion of the plate. The outer peripheral surface of a cylindrical ring made of the same material as the plate is brought into contact with the turbine housing, and the end of the ring is formed. A gas seal portion, wherein a contact portion between the outer peripheral surface of the ring and the turbine housing and a contact portion between the outer peripheral surface of the ring and the plate are fitted to the step portion of the plate. .

Therefore, according to the gas seal structure of the turbocharger of the first invention, since a gap is provided between the outer peripheral surface of the plate and the turbine housing, a difference in thermal expansion between the plate and the turbine housing is provided. There is no danger that the plate will be deformed by this. The exhaust gas is sealed at a contact portion (gas seal portion) between the outer peripheral surface of the ring and the turbine housing and the plate. Further, since the plate and the ring have the same coefficient of thermal expansion and the ring has a lower rigidity than the turbine housing, there is no possibility that the plate is deformed due to a difference in thermal expansion between the plate and the ring.

That is, according to the gas seal structure of the turbocharger of the first invention, the deformation of the plate can be avoided with a slight increase in cost by adding one ring.

In the gas seal structure for a turbocharger according to a second aspect of the present invention, a gap is provided between the outer peripheral surface of a ring-shaped plate provided on the end face side of the vane and the turbine housing. The peripheral portion extends to a back plate of the same material as the plate provided on the back side of the turbine wheel, and is fitted to a step formed on the back plate to form a contact portion between the inner peripheral surface of the plate and the back plate. Is a gas seal portion.

Therefore, according to the gas seal structure of the turbocharger of the second invention, since a gap is provided between the outer peripheral surface of the plate and the turbine housing, a difference in thermal expansion between the plate and the turbine housing is provided. There is no danger that the plate will be deformed by this. The exhaust gas is sealed at a contact portion (gas seal portion) between the outer peripheral surface of the plate and the back plate. Further, since the plate and the back plate have the same coefficient of thermal expansion, and the back plate is smaller than the turbine housing, there is no possibility that the plate is deformed due to the difference in thermal expansion between the plate and the back plate.

That is, according to the gas seal structure of the turbocharger of the second invention, without adding a new part,
Deformation of the plate can be avoided only by processing the back plate and changing the shape of the plate, and assembling is easier because the number of parts is smaller than in the first invention.

[Brief description of the drawings]

FIG. 1A is a sectional view showing a gas seal structure of a VG turbocharger according to Embodiment 1 of the present invention with a lower half omitted, and FIG. 1B is an extracted ring of the gas seal structure. FIG.

FIG. 2 is a cross-sectional view illustrating a gas seal structure of a VG turbocharger according to a second embodiment of the present invention with a lower half omitted.

FIG. 3 is a cross-sectional view showing a configuration of a conventional VG turbocharger.

FIG. 4 is an enlarged view of a portion A in FIG. 3;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Turbine housing 4 Turbine wheel 11 Vane 20 Plate 20a Step part 21, 26 Gap 22, 23 Contact part (gas seal part) 25 Ring 30 Plate 31 Contact part 33 Back plate 33a Step part 34, 35 Gap

Claims (2)

[Claims] 1. A gap is provided between an outer peripheral surface of a ring-shaped plate provided on an end surface side of a vane and a turbine housing, and a step is formed on an inner peripheral portion of the plate, and the same material as the plate is used. Then, the outer peripheral surface of the cylindrical ring is brought into contact with the turbine housing, and the end of the ring is fitted into the step of the plate, so that the contact portion between the outer peripheral surface of the ring and the turbine housing and the ring A gas seal structure for a turbocharger, wherein a contact portion between an outer peripheral surface and the plate is a gas seal portion. 2. A gap is provided between an outer peripheral surface of a ring-shaped plate provided on an end surface side of a vane and a turbine housing, and an inner peripheral portion of the plate is provided with a plate provided on a back side of a turbine wheel. A turbocharger which extends to a back plate of the same material, is fitted to a step formed on the back plate, and a contact portion between the inner peripheral surface of the plate and the back plate is a gas seal portion. Gas seal structure of machine.