JP2005098267A - Supercharger - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a supercharger capable of easy installation to an engine. <P>SOLUTION: The supercharger 1 includes a turbine 2 including a turbine impeller 12 driven by exhaust gas flow of the engine which is not indicated, a compressor 3 driven by the turbine 2 and pressure-feeding air to the engine, and a casing 4 provided between the turbine and compressor 3 and supporting the turbine 2 and the compressor 3. The casing 4 is provided with a cooling air chamber 21 with adjoining the turbine 2. A cooling air passage 22 connected to the compressor 3 and having part of air pressure-fed by the compressor 13 fed therein is connected to the cooling air chamber 21. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an exhaust turbocharger.

An exhaust turbocharger is mounted on an engine such as a ship, a car, or a generator, for example, and forcibly supplies air into the combustion chamber of the engine to improve combustion efficiency and This is intended to improve output.
An exhaust turbo-type supercharger (hereinafter referred to as “supercharger”) includes a turbine driven by an exhaust gas flow of an engine, a compressor driven by the turbine to pump outside air to the engine, and the turbine and the compressor. And a supporting casing.
The turbine has a turbine impeller that rotates by receiving an exhaust gas flow, and the compressor has a compressor impeller that pumps outside air by being driven to rotate. The turbine impeller and the compressor impeller are connected to each other through a rotating shaft so as to be coaxial and restrict relative rotation. The rotating shaft is supported by the casing via a bearing, and is allowed to rotate about its axis.
That is, when the turbine impeller rotates, the compressor impeller also rotates around the rotation axis, and external air is pumped by the compressor.
Here, lubricating oil is supplied to the bearing through a lubricating system from a lubricating oil reservoir or the like to prevent seizure.

  The turbine impeller has a substantially disk shape, and is provided so as to be concentric with respect to the rotation axis and restricted from rotating about the axis. In the turbine impeller, a plurality of blades extending in the radial direction from the center of rotation are provided on the surface facing the side opposite to the compressor (the surface facing the side opposite to the casing) along the circumferential direction. The turbine impeller is supplied with an exhaust gas flow from the outside in the radial direction, and the exhaust gas flow applied to the blades and contributing to the rotation of the turbine impeller is discharged in the axial direction from the surface side where the blades are provided. It has become.

  Here, outside air is pumped from the compressor to the space between the casing and the turbine impeller through the seal air passage. Thus, the outside air (seal air) is pumped into the space between the casing and the turbine impeller, so that the internal pressure of this space becomes a positive pressure. This prevents the exhaust gas from flowing into the casing from the turbine, and pushes back the turbine impeller that receives the thrust force from the exhaust gas flow toward the compressor, thereby reducing the thrust load applied to the bearing. Yes.

Here, when the engine speed is low, the turbine rotation speed is low, and the amount of outside air pumped into the engine by the compressor is small, the outside air in the compressor is sucked by the intake air of the engine. In some cases, the internal pressure becomes negative.
In this case, the exhaust gas in the turbine flows into the casing through the seal air passage, and the lubricating oil supplied to the bearing is sucked into the casing.
Therefore, a vacuum breaker is provided in the seal air passage to open the seal air passage to the outside of the casing when the internal pressure on the compressor side becomes a negative pressure and keep the internal pressure of the seal air passage at a positive pressure.
A turbocharger having such a configuration is described in, for example, Patent Document 1 described later.

JP 2002-70569 A (paragraphs [0002] to [0004] and FIG. 1)

However, since the turbocharger drives the turbine by the exhaust gas flow, heat is transferred from the turbine in contact with the high-temperature exhaust gas flow (about 500 ° C.) to the casing, and the bearing provided in the casing or the bearing of this bearing A member that is vulnerable to heat, such as a lubrication system that performs lubrication, is heated.
If these heat-sensitive members such as bearings and lubrication systems are overheated, problems such as seizure of the rotating shaft and the bearings will occur. Conventionally, a water chamber is provided in the casing, and this has been done from the outside of the casing. By supplying cooling water into the water chamber, the casing was cooled, and the heat-sensitive member provided in the casing was protected.
However, when such a water cooling structure is adopted, it is necessary to provide the casing with pipes such as a water supply pipe for supplying cooling water and a drain pipe for discharging used water, and ancillary equipment. There is. For this reason, the supercharger adopting such a water cooling structure takes time to install.

  This invention is made | formed in view of such a situation, Comprising: It aims at providing the supercharger which can be easily installed with respect to an engine.

In order to solve the above problems, the supercharger of the present invention employs the following means.
That is, the supercharger according to the present invention includes a turbine in which a turbine impeller is rotationally driven by an exhaust gas flow of the engine, a compressor that is driven by the turbine and pumps outside air to the engine, the turbine and the compressor. A turbocharger having a supporting casing, wherein the casing is provided with a cooling air chamber adjacent to the turbine, and the cooling air chamber is connected to the compressor so that the compressor is pumped. A cooling air passage into which a part of the outside air is fed is connected.

In the turbocharger configured as described above, the casing is provided with a cooling air chamber adjacent to the turbine, and a part of the outside air pressure-fed by the compressor passes through the cooling air passage in the cooling air chamber. It is supposed to be sent. Since this outside air is sufficiently cooler than the portion of the casing that receives heat from the turbine, it acts as a refrigerant that cools the area near the cooling air chamber in the casing.
That is, the region of the casing that receives heat from the turbine is cooled by the outside air sent into the cooling air chamber, and overheating of members provided in the casing, such as bearings and lubrication systems, is prevented.
Here, outside air is always sent into the cooling air chamber while the compressor is operating. That is, the casing is always cooled while the supercharger is operating.
Further, since the cooling air chamber is provided in the casing adjacent to the turbine in this way, the heat transfer area due to heat conduction from the side close to the turbine to the other part (part away from the turbine) in the casing is reduced. small. That is, since the heat from the turbine is not easily transmitted to the other member side of the casing, a sufficient cooling effect can be obtained even with air cooling.
Here, a part or the whole of the cooling air passage may be constituted by a pipe line provided outside the casing, but the whole is formed inside the casing so that a new member is not required to be provided outside the casing. It is preferable that it is comprised by the made channel | path.

  The supercharger according to the present invention is the supercharger according to claim 1, wherein the casing is connected to the compressor, and a part of the outside air supplied by the compressor is transferred to the casing and the turbine blades. A seal air passage leading to a space between the vehicle and the vehicle is provided, and at least a part of the seal air passage constitutes the cooling air passage.

In the supercharger configured as described above, the outside air is pressure-fed through the seal air passage from the compressor to the space between the casing and the turbine impeller. That is, seal air is supplied to the space between the casing and the turbine impeller.
And since the cooling air passage and the seal air passage share at least a part, the structure of these passages becomes simple, compared with the case where the cooling air passage and the seal air passage are provided independently, The turbocharger can be easily designed and manufactured.

  The supercharger according to the present invention is the supercharger according to claim 1 or 2, wherein the cooling air chamber is provided with a discharge port leading to a space between the casing and the turbine impeller. It is characterized by.

In the supercharger configured as described above, the outside air supplied into the cooling air chamber is used as a refrigerant and then supplied to the space between the casing and the turbine impeller through the discharge port. That is, the outside air supplied into the cooling air chamber is also used as seal air for preventing the inflow of exhaust gas from the turbine into the casing and reducing the thrust force applied to the turbine impeller.
In the supercharger according to the present invention, since the outside air used for cooling the casing in this way is also used as the seal air, the compressor is compared with the case where the cooling air and the seal air are separately taken out from the compressor. The amount of outside air to be taken out can be reduced.
As a result, the cooling of the casing and the prevention of the inflow of exhaust gas into the casing, while maintaining the performance of the supercharger by preventing the decrease in the amount of the outside air supplied to the engine from the outside air pumped by the compressor Can do.

The supercharger configured in this way cools the casing using a part of the outside air pumped by the compressor as a refrigerant.
For this reason, in the supercharger according to the present invention, pipes and incidental equipment for supplying a coolant such as cooling water from the outside are not required as in the conventional supercharger, so that the supercharger according to the present invention is easily installed in the engine. .
Moreover, since this supercharger does not need to consider the piping arrangement in the installation in an engine, it has a high degree of freedom of the installation form in an engine.

An embodiment of the present invention will be described below with reference to the drawings.
As shown in FIGS. 1 and 2 (enlarged view of FIG. 1), the turbocharger 1 according to the present embodiment is driven by an exhaust gas flow of an engine (not shown), and is driven by the turbine 2. It has a compressor 3 that pumps outside air to the engine, and a casing 4 that is provided between the turbine 2 and the compressor 3 and supports them.
A rotating shaft 6 is inserted into the casing 4 with one end protruding toward the turbine 2 and the other end protruding toward the compressor 3. The rotating shaft 6 is supported by a bearing 7 provided in the casing 4 so as to be rotatable around the axis. The casing 4 is provided with a lubricating oil supply passage 8 for supplying lubricating oil from a lubricating oil reservoir (not shown) to the bearing 7.

The turbine 2 is connected to an exhaust system of the engine and is supplied with at least a part of the exhaust gas flow of the engine, and a turbine that rotates by receiving the exhaust gas flow supplied into the exhaust gas introduction passage 11. And an impeller 12.
The turbine impeller 12 has a substantially disk shape, and is provided with respect to the end of the rotating shaft 6 on the turbine 2 side so as to restrict the rotation around the axis.
On the surface of the turbine impeller 12 facing away from the casing 4, a plurality of blades 12 a extending from the rotation center toward the radially outer side are provided along the circumferential direction.
The turbine impeller 12 is provided in a state where the surface facing the casing 4 is close to the casing 4. As shown in FIG. 2, a concavo-convex portion 12 b made of concavo-convex provided concentrically with the turbine impeller 12 is provided on the outer peripheral edge of the surface facing the casing 4.

The exhaust gas passage 11 is connected to the exhaust system of the engine and is provided so as to surround the radially outer side of the turbine impeller 12. The exhaust passage 11 is provided on the blade 12 a side of the turbine impeller 12 and passes through the turbine impeller 12. And a delivery path 11b that guides the exhaust gas flow outside the system or to an exhaust gas purification device (not shown).
That is, from the supply path 11a, an exhaust gas flow is supplied from the radially outer side to the turbine impeller 12, and the exhaust gas flow supplied to the turbine impeller 12 is discharged to the blade 12a side of the turbine impeller 12. Thus, it flows into the delivery path 11b.

The compressor 3 includes a compressor impeller 16 that sends outside air radially outward by being driven to rotate, and a spiral chamber 17 that surrounds the compressor impeller 16 and compresses the outside air sent by the compressor impeller 16. doing.
The compressor impeller 16 has a substantially disk shape, and is provided with respect to the end of the rotating shaft 6 on the compressor 3 side so as to be restricted from rotating coaxially and around the axis.
On the surface of the compressor impeller 16 facing away from the casing 4, a plurality of blades 16a extending from the center of rotation toward the radially outer side are provided along the circumferential direction.
The compressor impeller 16 is provided in a state where the surface facing the casing 4 is close to the casing 4. As shown in FIG. 2, a concavo-convex portion 16 b made of concavo-convex provided concentrically with the compressor impeller 16 is provided on the outer peripheral edge of the surface facing the casing 4.

As shown in FIG. 3, the casing 4 is provided with a concavo-convex portion 4 a concentrically with the concavo-convex portion 12 b at a portion facing the concavo-convex portion 12 b of the turbine impeller 12. These concavo-convex portions 4 a and 12 b constitute labyrinth fins that seal the space S between the casing 4 and the turbine impeller 12.
Similarly, in the casing 4, an uneven portion 4 b is provided at a portion facing the uneven portion 16 b of the compressor impeller 16 so as to be concentric with the uneven portion 16 b, and the uneven portions 4 b and 16 b are provided in the casing 4. And a labyrinth fin for sealing a space between the compressor impeller 16 and the compressor impeller 16.

As shown in FIGS. 1 and 2, the casing 4 is provided with a cooling air chamber 21 adjacent to the turbine 2. The cooling air chamber 21 is provided over almost the entire region of the turbine 2 facing the turbine impeller 12 as shown in FIGS.
As shown in FIG. 4 (AA arrow cross-sectional view in FIG. 1), the cooling air chamber 21 is connected to the swirl chamber 17 of the compressor 3 and is supplied with a part of the outside air pressure-fed by the compressor 3. A passage 22 is connected.
The cooling air passage 22 is configured by a hole drilled in the casing 4.
Further, the cooling air chamber 21 is provided with a discharge port 23 communicating with the space S between the casing 4 and the turbine impeller 12. Here, the cooling air chamber 21 communicates with the outside of the casing 4 through a flow path (not shown) other than the discharge port 23 at a position spaced from the cooling air passage 21.

  Here, the cooling air passage 22 has a cooling air passage when the pressure on the compressor 3 side (upstream side) is equal to or lower than the pressure on the turbine 2 side (downstream side) so that the internal pressure is always kept at a positive pressure. A vacuum breaker 24 that opens 22 out of the casing 4 is provided.

In the turbocharger 1 configured as described above, the casing 4 is provided with a cooling air chamber 21 adjacent to the turbine 2, and a part of the outside air pressure-fed by the compressor 3 is provided in the cooling air chamber 21. Are fed through the cooling air passage 22.
Since this outside air is sufficiently cooler than the portion that receives heat from the turbine 2 in the casing 4, it acts as a refrigerant that cools the area in the vicinity of the cooling air chamber 21 in the casing 4.
That is, the region of the casing 4 that receives heat from the turbine 2 is cooled by the outside air sent into the cooling air chamber 21, and overheating of members provided in the casing 4, such as the bearing 7 and the lubrication system, is prevented.
Here, outside air is always sent into the cooling air chamber 21 while the compressor is operating. That is, the casing is always cooled while the supercharger is operating.

  Further, since the casing 4 is provided with the cooling air chamber 21 adjacent to the turbine 2 in this manner, heat from the side close to the turbine 2 to the other part (part away from the turbine 2) in the casing 4. The heat transfer area by conduction is small. That is, since the heat from the turbine 2 is not easily transmitted to the other member side of the casing 4, a sufficient cooling effect can be obtained even with air cooling.

As described above, the supercharger 1 according to the present embodiment is configured to cool the casing 4 using a part of the outside air pumped by the compressor 3 as a refrigerant.
For this reason, since this supercharger 1 does not require piping and incidental equipment for supplying a coolant such as cooling water from the outside, unlike the conventional supercharger, it is easy to install in the engine.
Moreover, since this supercharger 1 does not need to consider the piping arrangement in the installation in an engine, it has a high degree of freedom of the installation form in an engine.

Further, the cooling air chamber 21 is provided with a discharge port 23 communicating with the space S between the casing 4 and the turbine impeller 12, and is supplied from the compressor 3 through the cooling air passage 22 into the cooling air chamber 21. Outside air is discharged from the discharge port 23.
That is, the cooling air passage 22, the cooling air chamber 21, and the discharge port 23 also serve as a seal air passage that guides a part of the outside air supplied by the compressor 3 to the space S between the casing 4 and the turbine impeller 12. The outside air supplied into the cooling air chamber 21 is used as a refrigerant and is then discharged through the discharge port 23 to prevent the inflow of exhaust gas from the turbine 2 into the casing 4 and the turbine impeller 12. It is also used as seal air to reduce the thrust force applied to the.
Thereby, compared with the case where the cooling air channel | path 22 and the seal air channel | path are each provided independently, design and manufacture of the supercharger 1 become easy.

  The cooling air chamber 21 is supplied with outside air having a flow rate higher than that necessary for sealing air. Of the outside air supplied into the cooling air chamber 21, air other than that used as sealing air is discharged out of the casing 4 through a flow path (not shown). That is, the flow rate of the outside air flowing through the cooling air chamber 21 is ensured enough for cooling the casing 4.

Moreover, in this supercharger 1, since the outside air used for cooling the casing 4 is also used as seal air, the compressor 3 is compared with a case where cooling air and seal air are separately taken out from the compressor 3. The amount of outside air to be taken out can be reduced.
Thus, the cooling of the casing 4 and the inflow of exhaust gas into the casing 4 are prevented, and the amount of the outside air supplied to the engine among the outside air pressure-fed by the compressor 3 is prevented from being reduced. Can be maintained.

  Here, in the present embodiment, an example in which the cooling air passage 22 is configured by a hole drilled in the casing 4 is shown. However, the present invention is not limited to this, and a part or the whole of the cooling air passage 22 is formed in the casing. 4 You may be comprised by the pipe line provided outside.

It is the longitudinal cross-sectional view which showed the structure of the supercharger concerning one Embodiment of this invention. It is an enlarged view of FIG. It is a BB arrow sectional view of Drawing 2. It is AA arrow sectional drawing of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Supercharger 2 Turbine 3 Compressor 4 Casing 12 Turbine impeller 21 Cooling air chamber (seal air passage)
22 Cooling air passage (seal air passage)
23 Discharge port (seal air passage)
S space

Claims (3)

A turbocharger having a turbine in which a turbine impeller is rotationally driven by an exhaust gas flow of the engine, a compressor driven by the turbine to pump outside air to the engine, and a casing that supports the turbine and the compressor. Machine,
The casing is provided with a cooling air chamber adjacent to the turbine,
An exhaust turbocharger, wherein a cooling air passage connected to the compressor and into which a part of the outside air pressure-fed by the compressor is sent is connected to the cooling air chamber. The casing is provided with a sealed air passage that is connected to the compressor and guides a part of the outside air supplied by the compressor to a space between the casing and the turbine impeller.
The turbocharger according to claim 1, wherein at least a part of the seal air passage constitutes the cooling air passage. 3. The exhaust turbocharger according to claim 1, wherein the cooling air chamber is provided with a discharge port that leads to a space between the casing and the turbine impeller.

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