JP5861287B2 - Turbocharger - Google Patents

Description

  The present invention relates to a turbocharger.

Conventionally, a turbocharger is sometimes mounted on a vehicle to improve fuel efficiency and output.
As shown in Patent Document 1, this turbocharger includes a turbine and a compressor. The turbine collects the energy contained in the exhaust gas as rotational power, and the recovered rotational power is used for the internal combustion engine. The supplied air is compressed.

  By the way, the turbine and the compressor include an impeller that is driven to rotate inside. In the turbocharger as described above, a plurality of blade bodies that rectify fluid in a turbine or a compressor may be arranged around the impeller.

JP 2008-215083 A JP 2009-144546 A

  Although the performance of the turbine and the compressor is improved by arranging the wing bodies as described above around the impeller, when the wing bodies are installed, as shown in Patent Document 2, on the back side of the nozzle plate on which the wing bodies are installed. A gap may be formed, and a leakage flow path that bypasses the upstream side and the downstream side of the wing body may be formed.

In recent years, a turbocharger using fixed wings fixed without rotating as the above-described wing body has been proposed, and there is a concern that the amount of leakage particularly in the leakage flow path increases in such a turbocharger.
This is so that the nozzle plate can be pressed against the housing so that the gap between the fixed wing and the housing is minimized, and a large flow path is formed when the nozzle plate moves. This is because there is a possibility of being.

When such a leakage channel is formed, a leakage flow that flows through the leakage channel occurs. This leakage flow may cause an increase in pressure loss and may result in blow-by gas flowing through the seal ring into an unintended region.
That is, when a leakage flow path is formed and a leakage flow is generated, it causes a decrease in performance due to an increase in pressure loss and an increase in blow-by gas.

  The present invention has been made in view of the above-described problems, and in a turbocharger in which fixed blades are arranged around an impeller, the leakage flow that bypasses the upstream side to the downstream side without passing through the fixed blades is reduced. With the goal.

  The present invention adopts the following configuration as means for solving the above-described problems.

  According to a first aspect of the present invention, there is provided a housing for accommodating an impeller in an impeller accommodating space communicating with a scroll flow path and accommodating a shaft connected to the impeller from an axial direction, and a plurality of fixed blades fixedly arranged around the impeller And a nozzle plate that is installed on the surface side facing the axial direction and is movable in the axial direction, and a pressing means that presses the nozzle plate toward the stationary blade side, and the nozzle A turbocharger having a leakage flow path connecting the scroll flow path and the impeller accommodating space on the back surface side of the plate, wherein an inlet portion for positioning the nozzle plate and the housing in the radial direction of the impeller is leaked. The configuration of having the inside of the flow path is adopted.

  According to a second invention, in the first invention, the housing includes an impeller housing that houses the impeller and a shaft housing that houses the shaft, and the nozzle plate and the shaft portion serve as the spigot portion. A configuration is adopted in which a first spigot part for positioning the housing is provided.

  According to a third aspect of the present invention, the second aspect of the present invention further includes a second spigot portion that positions the nozzle plate and the impeller housing as the spigot portion.

  According to a fourth aspect of the present invention, in the first to third aspects of the present invention, the inlay portion is arranged on the upstream side of the flow in the leakage flow path with respect to the pressing means.

  According to a fifth invention, in any one of the first to fourth inventions, the material of the nozzle plate and the impeller housing, or the clearance in the impeller portion that positions the nozzle plate and the impeller housing is A configuration is adopted in which the clearance in the inlay portion is set to be ensured.

The present invention has a leak passage on the back side of the nozzle plate opposite to the surface on which the fixed blade is installed, but has an inlay portion for positioning the nozzle plate and the housing inside the leak passage.
The inlay portion is for fitting the nozzle plate and the housing together, and is for positioning by restricting relative movement between the nozzle plate and the housing. In such an inlay portion, the nozzle plate and the housing are not in pressure contact with each other, but are lightly in contact with each other or arranged very close to each other.
For this reason, as in the present invention, when the spigot portion is disposed inside the leak passage, the fluid passing through the leak passage must pass through the spigot portion. That is, according to the present invention, the pressure loss of the leakage flow path increases, and it becomes difficult for the fluid to pass through the leakage flow path.
Therefore, according to the present invention, in the turbocharger in which the fixed blades are arranged around the impeller, it is possible to reduce the leakage flow that bypasses the upstream side to the downstream side without passing through the fixed blades.

In recent years, a fixed blade type that can suppress the formation of a gap between the fixed blade and the flow path wall even during operation by fixing the fixed blade to the nozzle plate and allowing the nozzle plate to move to the fixed blade side. A turbocharger has been proposed.
According to such a turbocharger, it is necessary to provide a gap around the nozzle plate in order to enable the nozzle plate to move, and this increases the leakage flow path. The present invention can reduce the amount of fluid leakage in the leakage flow path, and is particularly suitable for a fixed-wing turbocharger in which a nozzle plate is movable.

It is sectional drawing which shows schematic structure of the turbocharger in one Embodiment of this invention. It is a principal part enlarged view of FIG.

  Hereinafter, an embodiment of a turbocharger according to the present invention will be described with reference to the drawings. In the following drawings, the scale of each member is appropriately changed in order to make each member a recognizable size.

FIG. 1 is a cross-sectional view showing a schematic configuration of a turbocharger S1 of the present embodiment.
The turbocharger S1 of this embodiment is mounted on an automobile, recovers energy contained in exhaust gas exhausted from the engine of the automobile as rotational power, and supplies air supplied to the engine using the rotational power. Compress.
And turbocharger S1 of this embodiment is provided with the turbine 1, the nozzle mechanism 2, the compressor 3, and the axial part 4, as shown in FIG.

  The turbine 1 recovers energy contained in exhaust gas as rotational power, and includes a turbine housing 1a (impeller housing) and a turbine impeller 1b (impeller).

The turbine housing 1a is a hollow member that forms the outer shape of the turbine 1, and a scroll flow path 1a1, an impeller accommodating space 1a2, and a connection flow path 1a3 are provided therein.
The scroll flow path 1a1 is a flow path for taking in the exhaust gas exhausted from the engine into the turbocharger S1, and is provided surrounding the turbine impeller 1b around the rotating shaft of the turbine impeller 1b.
The impeller accommodating space 1a2 is an area for accommodating the turbine impeller 1b, and is provided in the center portion of the turbine housing 1a when viewed from the rotation axis direction of the turbine impeller 1b. As shown in FIG. 1, the turbine housing 1a is provided with an exhaust port 1a4 for discharging exhaust gas, and the impeller accommodating space 1a2 is connected to the exhaust port 1a4.
The connection flow path 1a3 is a flow path provided between the scroll flow path 1a1 and the impeller accommodating space 1a2. As shown in FIG. 1, the connection flow path 1a3 is provided between an inner wall surface of the turbine housing 1a and a nozzle plate 2a (described later) provided in the nozzle mechanism 2, and is a nozzle fixed to the nozzle plate 2a. This is a flow path in which the blade 2b (fixed blade) is disposed.

  The turbine impeller 1b is a radial impeller that is housed in the impeller housing space 1a2 as described above, and is rotationally driven by the exhaust gas that is supplied from the scroll passage 1a1 through the connection passage 1a3.

  The nozzle mechanism 2 rectifies the exhaust gas supplied from the scroll flow path 1a1 to the turbine impeller 1b in the connection flow path 1a3, and includes a nozzle plate 2a and a plurality of nozzle blades 2b.

The nozzle plate 2a is a disk-shaped plate for installing the nozzle blades 2b, and an opening is provided at the center so that the turbine impeller 1b can be inserted.
The nozzle plate 2a is set to have a larger diameter than the turbine impeller 1b when viewed from the rotational axis direction of the turbine impeller 1b, and the nozzle blade 2b is provided in a region protruding from the turbine impeller 1b.
In the turbocharger S1 of the present embodiment, the nozzle plate 2a is interposed between the turbine impeller 1b and a shaft housing 4a (described later) of the shaft portion 4, so that heat from the turbine 1 to the shaft portion 4 is transferred. It also functions as a heat shield for suppressing transmission.

The nozzle blades 2b rectify the exhaust gas supplied to the turbine impeller 1b in the connection flow path 1a3. When viewed from the direction of the rotation axis of the turbine impeller 1b, the nozzle blades 2b are annularly spaced at equal intervals around the rotation axis. Multiple sequences are arranged.
The nozzle blade 2b forms a gap channel (nozzle) between the adjacent nozzle blades 2b. The exhaust gas is rectified by passing through the gap flow path.

Further, the turbocharger S1 of the present embodiment includes a disc spring 5 that presses the nozzle plate 2a toward the turbine housing 1a and biases it.
The disc spring 5 is inserted between the nozzle plate 2a and the shaft housing 4a, and presses the nozzle blade 2b against the inner wall of the turbine housing 1a by urging the nozzle plate 2a toward the turbine housing 1a. This reduces the gap between the nozzle blade 2b and the turbine housing 1a.

  The compressor 3 compresses air supplied to the engine using the rotational power obtained by the turbine 1, and includes a compressor housing 3a and a compressor impeller 3b.

The compressor housing 3a is a hollow member that forms the outer shape of the compressor 3, and is provided with a scroll flow path 3a1, an impeller accommodating space 3a2, and a connection flow path 3a3.
The scroll flow path 3a1 is a flow path for guiding the air compressed by the compressor impeller 3b to the engine, and is provided surrounding the compressor impeller 3b around the rotation axis of the compressor impeller 3b.
The impeller accommodating space 3a2 is an area for accommodating the compressor impeller 3b, and is provided at the center of the compressor housing 3a when viewed from the rotation axis direction of the compressor impeller 3b. As shown in FIG. 1, the compressor housing 3a is provided with a suction port 3a4 for taking in air, and the impeller accommodating space 3a2 is connected to the suction port 3a4.
The connection flow path 3a3 is a flow path provided between the scroll flow path 3a1 and the impeller accommodating space 3a2.

The compressor impeller 3b is a radial impeller that is housed in the impeller housing space 3a2 as described above, and is rotationally driven by the rotational power transmitted from the turbine impeller 1b via the shaft portion 4.
And the compressor impeller 3b compresses the air taken in from the suction port 3a4, and sends it into the scroll flow path 3a1 through the connection flow path 3a3.

The shaft portion 4 transmits the rotational power recovered by the turbine 1 to the compressor 3, and is disposed between the turbine 1 and the compressor 3.
As shown in FIG. 1, the shaft portion 4 includes a shaft housing 4a and a shaft 4b.

The shaft housing 4a is a hollow member that forms the outer shape of the shaft 4 and has a shaft housing space 4a1 for housing the shaft 4b therein.
The shaft housing 4a is disposed between the turbine housing 1a and the compressor housing 3a, and is fixed to the turbine housing 1a and the compressor housing 3a.
In addition, a flow path for lubricating oil that lubricates and cools the shaft 4b is formed inside the shaft housing 4a, and the shaft housing 4a is connected to the lubricant supply and recovery device (not shown). Has been.

The shaft 4b is housed in the shaft housing space 4a1 of the shaft housing 4a, and is supported by a bearing (not shown).
One end of the shaft 4b is connected to the turbine impeller 1b from the axial direction, and the other end is connected to the compressor impeller 3b. The shaft 4b rotates with the rotation of the turbine impeller 1b and simultaneously rotates the compressor impeller 3b.
In addition, a seal ring 4c for reducing blow-by gas is installed between the shaft 4b and the shaft housing 4a as shown in FIG.

  In the present embodiment, the turbine housing 1a, the compressor housing 3a, and the shaft housing 4a constitute the housing of the present invention.

In the turbocharger S1 of the present embodiment, gaps are provided between the nozzle plate 2a and the turbine housing 1a and between the nozzle plate 2a and the shaft housing 4a.
For this reason, in such a turbocharger S1, the nozzle plate 2a is slightly movable in the rotational axis direction of the turbine impeller 1b.

  As described above, when the nozzle plate 2a is movable in the direction of the rotation axis of the turbine impeller 1b, even if each member is deformed by thermal expansion due to a high temperature environment during movement, the biasing force of the disc spring 5 Thus, the nozzle plate 2a can always be urged toward the inner wall surface of the turbine housing 1a. Therefore, the gap (nozzle side clearance) between the nozzle blade 2b and the turbine housing 1a can always be minimized.

However, in order to allow the nozzle plate 2a to move slightly in the direction of the rotation axis of the turbine impeller 1b as described above, the nozzle plate 2a is interposed between the nozzle plate 2a and the turbine housing 1a and between the nozzle plate 2a and the shaft housing 4a. Will be provided with a gap. Therefore, as shown in the enlarged view of FIG. 2, if the side on which the nozzle blades 2b of the nozzle plate 2a are installed is the surface (the surface facing the axial direction of the turbine impeller 1b), the scroll is performed on the back side of the nozzle plate 2a. A leakage flow path R connecting the flow path 1a1 and the impeller accommodating space 1a2 is formed.
When such a leakage flow path R is formed, a part of the exhaust gas is supplied to the turbine impeller 1b without passing through the nozzle blade 2b, so that the gap between the nozzle blade 2b and the turbine housing 1a is minimized. The effect of the limit will not be obtained to the maximum.

In contrast, in the turbocharger S1 of the present embodiment, an inlay portion (hereinafter referred to as a second inlay portion 10) that positions the nozzle plate 2a and the turbine housing 1a in the radial direction of the turbine impeller 1a is a leakage flow path R. Has inside.
The second inlay portion 10 is constituted by a side wall surface 11 of the nozzle plate 2 a and an inner wall surface 12 of the turbine housing 1 a facing the side wall surface 11. The side wall surface 11 and the inner wall surface 12 are provided over the entire circumference of the nozzle plate 2a and the turbine housing 1a with the rotation shaft as a center, as viewed from the rotation shaft direction of the turbine impeller 1b. And the side wall surface 11 and the inner wall surface 12 are opposingly arranged over the perimeter, and the nozzle plate 2a and the turbine housing 1a are positioned correctly. When the nozzle plate 2a and the turbine housing 1a are positioned, the side wall surface 11 and the inner wall surface 12 are not pressed against each other and are placed in light contact or very close to each other.

Further, in the turbocharger S1 of the present embodiment, an inlay portion (hereinafter referred to as a first inlay portion 20) that positions the shaft portion housing 4a and the nozzle plate 2a in the radial direction of the turbine impeller 1a is disposed inside the leakage flow path R. Have.
The first inlay portion 20 includes a side wall surface 21 that faces the inside of the protruding portion 2a1 that protrudes toward the compressor 3 of the nozzle plate 2a, and an inner wall surface 22 of the shaft portion housing 4a that faces the side wall surface 21. Yes. The side wall surface 21 and the inner wall surface 22 are provided over the entire circumference of the nozzle plate 2a and the shaft housing 4a with the rotation shaft as a center when viewed from the rotation shaft direction of the turbine impeller 1b. And the side wall surface 21 and the inner wall surface 22 are opposingly arranged over the perimeter, and the nozzle plate 2a and the axial part housing 4a are positioned correctly. When the nozzle plate 2a and the shaft housing 4a are positioned, the side wall surface 21 and the inner wall surface 22 are not in pressure contact with each other and are placed in light contact or very close to each other.

In the turbocharger S1 of this embodiment having such a configuration, when exhaust gas is supplied from the engine to the turbine 1, the exhaust gas is supplied to the turbine impeller 1b via the scroll flow path 1a1 and the connection flow path 1a3. Is done.
When the exhaust gas is supplied to the turbine impeller 1b, the turbine impeller 1b is rotationally driven by the flow of the exhaust gas, whereby the energy contained in the exhaust gas is recovered as rotational power.
The exhaust gas from which energy has been recovered is discharged to the outside of the turbocharger S1 through the exhaust port 1a4.

When the turbine impeller 1b is rotationally driven, rotational power is transmitted to the compressor impeller 3b via the shaft 4b, and thereby the compressor impeller 3b is rotationally driven.
As a result, the air taken in from the suction port 3a4 is compressed by the compressor impeller 3b, and the compressed air is supplied to the engine via the connection flow path 3a3 and the scroll flow path 3a1.

In such a turbocharger S1 of the present embodiment, although the leakage flow path R is provided on the back surface side of the nozzle plate 2a, the first inlay for positioning the nozzle plate 2a and the shaft housing 4a inside the leakage flow path R. Part 20.
Here, the first spigot part 20 is for fitting and positioning the nozzle plate 2a and the shaft part housing 4a, and restricts relative movement between the nozzle plate 2a and the shaft part housing 4a. Position it. In such a first inlay portion 20, the nozzle plate 2a and the shaft portion housing 4a are not pressed against each other, but are placed in light contact or in close proximity.
For this reason, when the 1st spigot part 20 is arrange | positioned inside the leak flow path R like the turbocharger S1 of this embodiment, the exhaust gas which passes the leak flow path R passes through the 1st spigot part 20. Will have to do. That is, according to the turbocharger S1 of the present embodiment, the pressure loss in the leakage flow path R increases, and the exhaust gas hardly passes through the leakage flow path R.
Therefore, according to the turbocharger S1 of the present embodiment, in the turbocharger in which the nozzle blades 2b are arranged around the turbine impeller 1b, the exhaust gas that bypasses from the upstream side to the downstream side without passing through the nozzle blades 2b is reduced. It becomes possible.

In the turbocharger S1 of the present embodiment, the nozzle blade 2b is fixed to the nozzle plate 2a, the nozzle plate 2a can be moved toward the nozzle blade 2b (in the axial direction of the turbine impeller 1a), and the nozzle plate 2a is further moved by a disc spring. By pressing at 5, the fixed-wing turbocharger can suppress the formation of a gap between the nozzle blade 2b and the flow path wall even during operation.
However, in order that the turbocharger S1 of this embodiment can move the nozzle plate 2a, it is necessary to provide a gap around the nozzle plate 2a, and the leakage flow path R is increased accordingly.
On the other hand, since the turbocharger S1 of the present embodiment can reduce the amount of exhaust gas leakage in the leakage flow path R by the first inlay portion 20, as described above, the nozzle blade 2b and the turbine housing 1a. The effect obtained by minimizing the gap between the two can be maximized.

Further, the turbocharger S1 of the present embodiment further includes a second spigot portion 10 that positions the turbine housing 1a and the nozzle plate 2a inside the leakage flow path R.
For this reason, the exhaust gas that passes through the leakage flow path R must pass through the second spigot section 10. Therefore, the pressure loss of the leakage flow path R is further increased, and the exhaust gas is less likely to pass through the leakage flow path R.
Therefore, according to the turbocharger S1 of the present embodiment, it is possible to further reduce the exhaust gas that bypasses the upstream side to the downstream side without passing through the nozzle blade 2b.

  In addition, the 2nd spigot part 10 does not necessarily need to be installed, and can also be abbreviate | omitted when the leak amount of exhaust gas can fully be reduced only by the 1st spigot part 20. FIG.

When the nozzle plate 2a and the turbine housing 1a are warmed by the exhaust gas, the nozzle plate 2a, the turbine housing 1a, and the shaft housing 4a may differ depending on the distance from the shaft housing 4a that is generally cooled. A difference in thermal expansion occurs between them.
For this reason, it is necessary to select the materials of the nozzle plate 2a, the turbine housing 1a, and the shaft housing 4a so that the clearance between the second spigot portion 10 and the first spigot portion 20 can be secured by the above-described difference in thermal expansion. .
On the other hand, when the material of the 2nd spigot part 10 and the 1st spigot part 20 cannot be selected, the clearance before a heating is set so that the clearance in the 2nd spigot part 10 and the 1st spigot part 20 can be secured at the time of heating. There is a need to.

Moreover, in this embodiment, the structure in which the spigot part is arrange | positioned in the upstream of the flow in the leak flow path R rather than the disk spring 5 was demonstrated.
Thereby, the supply amount of the exhaust gas to the disc spring 5 can be reduced, and the disc spring 5 can be prevented from being thermally deformed.

  As mentioned above, although preferred embodiment of this invention was described referring drawings, this invention is not limited to the said embodiment. Various shapes, combinations, and the like of the constituent members shown in the above-described embodiments are examples, and various modifications can be made based on design requirements and the like without departing from the gist of the present invention.

For example, in the above-described embodiment, the configuration in which the fixed blades provided on the nozzle plate are arranged in the connection flow path 1a3 of the turbine 1 has been described.
However, the present invention is not limited to this, and a configuration in which fixed blades provided on the nozzle plate are arranged in the connection flow path 3a3 of the compressor 3 can also be adopted.
At this time, if a leakage flow path is generated on the back surface side of the nozzle plate, the spigot portion that aligns the nozzle plate and the shaft housing (impeller housing), and further aligns the nozzle plate and the compressor housing. You may install an inlay part in the said leakage flow path.
Accordingly, it is possible to reduce the amount of air leaking through the leakage flow path on the back surface side of the nozzle plate.

  S1 ... turbocharger, 1 ... turbine, 1a ... turbine housing (impeller housing), 1b ... turbine impeller (impeller), 2 ... nozzle mechanism, 2a ... nozzle plate, 2b ... nozzle blade (blade) ), 3... Compressor, 3a... Compressor housing, 4... Shaft portion, 4a... Shaft portion housing, 5... Disc spring (pressing means), 10. ... First inlay section (inlay section)

Claims (4)

A housing that houses the impeller in the impeller housing space that communicates with the scroll flow path and houses a shaft that is connected to the impeller from the axial direction;
A plurality of fixed blades fixedly arranged around the impeller, and a nozzle plate in which the fixed blades are installed on the surface side facing the axial direction and are movable in the axial direction;
A pressing means for pressing the nozzle plate toward the fixed blade;
Have
A turbocharger having a leakage flow path connecting the scroll flow path and the impeller accommodating space on the back side of the nozzle plate,
Have a spigot portion for positioning and said and said nozzle plate housing in the radial direction of the impeller within said leakage flow path,
The housing includes an impeller housing that houses the impeller, and a shaft housing that houses the shaft;
A turbocharger comprising a first inlay portion for positioning the nozzle plate and the shaft housing as the inlay portion . Examples spigot portion, the turbocharger according to claim 1, further comprising a second spigot portion for positioning and said impeller housing and said nozzle plate. 3. The turbocharger according to claim 1, wherein the first inlay portion is disposed on the upstream side of the flow in the leakage flow path with respect to the pressing means. The material of the nozzle plate and the impeller housing, or the clearance in the spigot portion that positions the nozzle plate and the impeller housing is set such that the clearance in the spigot portion can be secured during heating. the turbocharger according to any one of claims 1-3.

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