JP2009236068A - Supercharger - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a supercharger enabling to generate great supporting force with high efficiency while reducing bearing loss and maintaining clean environment. <P>SOLUTION: In a bearing housing 32, a static pressure air shaft 40 is provided for supporting a driving shaft 31 rotatably around an axis O in no contact. On the sides of disc back faces 11a, 21a of a turbine impeller 11 and a compressor impeller 21, a first partition plate 60 and a second partition plate 70 are provided, respectively, for partitioning the bearing housing 32 with the driving shaft 31 being inserted therethrough. Between each of the disc back faces 11a, 21a and each of the partition plates 60, 71, labyrinth seals 61, 71 are provided, respectively, for preventing the entry of high pressure fluid from the turbine impeller 11 and the compressor impeller 21 into the bearing housing 32. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a supercharger in which a bearing for supporting a drive shaft is provided in a bearing housing located between a turbine housing and a compressor housing.

  As is well known, in a turbocharger, a radial turbine and a compressor are arranged on the same rotating shaft, a turbine impeller in the radial turbine and a compressor impeller in the compressor are connected by a drive shaft, and the turbine impeller is connected to an exhaust gas or the like. Is configured such that the compressor impeller rotates through the drive shaft and the air or the like is compressed (see, for example, Patent Document 1).

In the above supercharger, a bearing (bearing) for supporting the drive shaft is provided in a bearing housing that is disposed between the radial turbine and the compressor and accommodates the drive shaft. Lubricating oil bearings (for example, see Patent Document 2) that employ oil as a lubricating medium for rotation and air bearings (for example, see Patent Document 3) that employ air are generally known.
JP 2006-125588 A JP 2006-837779 A JP-A-62-17321

By the way, the conventional turbocharger as described above has the following problems.
That is, in the case of the bearing using the lubricating oil, there is a problem that the rotational efficiency is poor because the bearing loss due to the viscosity of the lubricating oil itself is large. Also. There is a risk that the lubricating oil may leak from the periphery of the drive shaft to the compressor, etc., and the oil component may be mixed in the compressed air, and impurities deposited from the lubricating oil may adhere to the bearing portion and reduce the rotational performance. was there.

  In addition, when an air bearing is used, high-pressure air is supplied to the drive shaft to support it in a non-contact manner, so that extra energy is required to increase the support force and support the drive shaft reliably. . Further, dust from the exhaust gas that rotates the radial turbine may enter the bearing portion and adversely affect the rotational performance of the bearing.

  SUMMARY OF THE INVENTION The present invention has been made in view of such a problem. A bearing capable of reducing bearing loss and maintaining a clean environment of the bearing portion and generating a large supporting force with high efficiency is provided. An object is to provide a supercharger equipped.

In order to solve the above problems, the present invention proposes the following means.
That is, the turbocharger according to the present invention is provided with a turbine housing and a compressor housing on both sides of a bearing housing therebetween, and a drive shaft that rotates about an axis is inserted into each of the housings. In a turbocharger in which a turbine impeller is provided on the drive shaft in the turbine housing and a compressor impeller is provided on the drive shaft in the compressor housing, the drive shaft is rotatable around the axis in the bearing housing. A non-contact hydrostatic air bearing is provided; a partition plate for partitioning each housing while the drive shaft is inserted is disposed on the back side of the disk of each impeller; Between the partition plate, Bin'inpera and high pressure fluid of the compressor impeller is characterized in that the seal that prevents from entering into the bearing housing.

According to the turbocharger having such a feature, the non-contact state can be maintained and the drive shaft can be reliably supported by using a hydrostatic air bearing without using lubricating oil. As a result, it is possible to reduce bearing loss and maintain a clean environment.
Here, the support force of the drive shaft by the hydrostatic air bearing is such that the pressure difference between the pressure of the atmosphere in which the hydrostatic air bearing is disposed and the high pressure air supplied to the hydrostatic air bearing is significant. Become. That is, when the pressure around the hydrostatic air bearing is high, the supporting force of the drive shaft by the high pressure air is impaired.
On the other hand, in the turbocharger of the present invention, by providing a pressure difference between the bearing housing in which the hydrostatic air bearing is disposed by the seal, the turbine housing, and the compressor housing, the periphery of the hydrostatic air bearing is provided. Therefore, it is possible to efficiently support the drive shaft without impairing the supporting force of the hydrostatic air bearing by the high-pressure air.
Furthermore, since the seal prevents dust from entering by exhaust gas in the turbine housing, the inside of the bearing housing can be maintained in a clean environment.

In the supercharger according to the present invention, the seal is a labyrinth seal.
Thereby, a pressure difference can be reliably and easily provided between the bearing housing, the turbine housing, and the compressor housing. Furthermore, since the non-contact state between the disk and each partition plate in each impeller can be maintained, the occurrence of rotation loss can be prevented.

  Furthermore, in the turbocharger according to the present invention, the hydrostatic air bearing includes a radial bearing that supports a radial direction of the drive shaft, and a thrust bearing that supports a thrust direction of the drive shaft, and the thrust bearing includes: A disk-shaped thrust collar that rotates together with the drive shaft is disposed opposite to the axial direction, and has injection holes that inject high-pressure air on both sides in the axial direction toward the thrust collar. Yes.

  As a result, the drive shaft can be stably supported in the radial direction and the thrust direction, and the position of the drive shaft in the axial direction can be securely fixed to realize non-contact support in the axial direction.

  According to the turbocharger according to the present invention, by adopting the hydrostatic air bearing, it is possible to maintain a clean environment while reducing bearing loss, and in the bearing housing, the turbine housing, and the compressor housing. By providing a pressure difference between them, the drive shaft can be supported efficiently and reliably without impairing the supporting force by the high-pressure air supplied to the hydrostatic air bearing.

Hereinafter, an embodiment of a supercharger according to the present invention will be described with reference to the drawings.
1 is a side sectional view showing the overall configuration of a turbocharger according to an embodiment of the present invention, FIG. 2 is an enlarged view of the vicinity of a hydrostatic air bearing in FIG. 1, and FIG. 3 is a view of the vicinity of the rear surface of a turbine impeller in FIG. FIG. 4 is an enlarged view of the vicinity of the back surface of the compressor impeller in FIG.

    As shown in FIG. 1, the supercharger 1 includes a radial turbine 10, a compressor 20, and a bearing portion 30, and a turbine impeller 11 provided in the radial turbine 10 and a compressor impeller 21 provided in the compressor 20 Are fixed to a drive shaft 31 that passes through the radial turbine 10, the compressor 20, and the bearing portion 30, and are rotated about the axis O.

  The turbine impeller 11 and the compressor impeller 21 are provided with a plurality of turbine blades 13 or compressor blades 23 around an axis O. The turbine impeller 11 rotates by receiving torque when exhaust gas blown from the outer peripheral side flows between adjacent turbine blades 13 and escapes in the direction of the axis O. The compressor impeller 21 is configured to compress the outside air flowing from the direction of the axis O to the outer peripheral side where the compressor blades 23 are erected by being driven to rotate.

The radial turbine 10 accommodates a turbine housing 12 in which a turbine impeller 11 and the like are accommodated, the compressor 20 accommodates a compressor housing 22 in which a compressor impeller 21 and the like are accommodated, and the bearing portion 30 accommodates a hydrostatic air bearing 40 and the like which will be described later. The turbine housing 12, the bearing housing 32, and the compressor housing 22 are sequentially connected to each other so that the radial turbine 10, the compressor 20, and the bearing portion 30 are fixedly integrated. Yes.
A first partition plate 60 that partitions the inside of the turbine housing 12 and the bearing housing 32 while the drive shaft 31 is inserted is provided on the disk rear surface 11 a side of the turbine impeller 11. Similarly, a second partition plate 70 that partitions the inside of the compressor housing 22 and the bearing housing 32 while the drive shaft 31 is inserted is provided on the disk rear surface 21 a side of the compressor impeller 21.

  In the bearing portion 30, the drive shaft 31 is disposed such that its axis is concentric with the rotation shafts of the turbine impeller 11 and the compressor impeller 21, that is, on the axis O, and the turbine impeller 11 is disposed at one end of the drive shaft 31. The compressor impeller 21 is integrally coupled to the other end portion via a nut 24.

The compressor housing 22 is formed with an intake port 22 a disposed coaxially with the drive shaft 31, that is, on the axis O, and outside air is sucked from the intake port 22 a by the rotation of the compressor impeller 21. Accordingly, since compressed air is present at the fluid outlet C of the compressor blade 23, the pressure at the fluid outlet C is high.
The compressor housing 22 has a discharge channel (not shown) protruding from the outer peripheral side. This discharge flow path is connected to an air supply port of the internal combustion engine, and guides the pressurized air to the internal combustion engine.

Further, a scroll flow path F is formed in the turbine housing 12. Further, the turbine housing 12 has an exhaust gas introduction path (not shown) protruding outward, and the exhaust gas introduction path is connected to an exhaust port of the internal combustion engine (not shown), and the internal combustion engine discharges. Exhaust gas is introduced into the scroll flow path F. The turbine blades 13 are rotated by the exhaust gas introduced into the scroll flow path F. At this time, the fluid inlet T of the turbine blade 13 becomes high pressure by the exhaust gas.
Further, the turbine housing 12 is formed with an exhaust gas discharge port 12 a arranged coaxially with the drive shaft 31. The exhaust gas discharge port 12a is connected to an exhaust pipe (not shown) or the like, and thereby exhaust gas is discharged to the outside.

  In the bearing housing 32, a hydrostatic air bearing 40 that supports the drive shaft 31 so as to be rotatable around the axis O is provided. Hereinafter, the configuration of the hydrostatic air bearing 40 will be described with reference to FIG.

The hydrostatic air bearing 40 has a bearing bush 41 having a substantially multi-stage cylindrical shape centering on the axis O, and supports the radial direction of the drive shaft 31 on the inner peripheral surface 41 a side of the bearing bush 41. Two radial bearings 42 and 42 are disposed, and a thrust bearing 43 that supports the thrust direction of the drive shaft 31 is disposed at the end portion of the bearing 20 that has a larger diameter than the compressor 20. .
In addition, the space in the bearing housing 32 surrounding the static pressure air bearing 40 is a hollow portion B that is in communication with the outside.

An air supply path 44 is formed inside the bearing bush 41, and the air supply path 44 extends in a direction parallel to the axis O and communicates with an air supply port 32 a opened in the bearing housing 32. An air passage 44a and a sub air supply passage 44b that is connected to the main air supply passage 44a and opens to the end face of the bearing bush 41 on the compressor 20 side are provided.
The bearing bush 41 has an annular groove 45 formed in an annular shape centering on the axis O so as to communicate with the main air supply path 44a and the inner peripheral surface 41a. Four are formed. Of these four annular grooves 45, the two annular grooves 45a, 45a located on the radial turbine 10 side are arranged with their distances close to each other, and the remaining two annular grooves 45b, 45b are radial. The two annular grooves 45a and 42a on the turbine 10 side are separated from each other and are arranged close to each other on the compressor 20 side.

  The radial bearing 42 has a cylindrical shape in which a plurality of injection holes 42 a are formed on the peripheral surface, and is inserted into the drive shaft 31 to correspond to the two annular grooves 45 a and 45 a on the radial turbine 10 side. And the portions corresponding to the two annular grooves 45b, 45b on the compressor 20 side. The radial bearing 42 is fixed in the direction of the axis O by a retaining ring 46 provided on the inner peripheral surface 41 a of the bearing bush 41.

  When high pressure air P is supplied from the outside to the air supply port 32a of the bearing housing 32, the high pressure air P reaches the radial bearing 42 via the main air supply passage 44a and the annular groove 45, and this radial bearing. The high-pressure air P narrowed down by the plurality of injection holes 42 a is sprayed onto the drive shaft 31. Thereby, the inner peripheral surface of the radial bearing 42 and the drive shaft 31 are brought into a non-contact state, and the drive shaft is supported in the radial direction so as to be rotatable around the axis O.

On the other hand, the thrust bearing 43 has an outer disk shape centered on the axis O, and an insertion hole 48 through which the drive shaft 31 is inserted is opened at the center. The outer peripheral edge 49 of the disk is a bearing. The bearing bush 41 is fixedly integrated with the bearing bush 41 by fitting into a fitting hole 41b formed on the end surface of the bush 41 on the compressor 20 side.
In addition, a hollow air supply passage 50 is formed inside the thrust bearing 43, and the hollow air supply passage 50 and the sub air supply passage 44b of the bearing bush 41 are brought into communication with each other. High-pressure air P is supplied to the air supply path 50.

Further, the thrust bearing 43 is formed with a plurality of injection holes 43 a in the circumferential direction that communicate the hollow air supply path 50 and the outside in parallel with the axis O. Further, on both sides of the thrust bearing 43 in the direction of the axis O, a disc-shaped thrust collar 51 fixed to the drive shaft 31 is disposed so as to sandwich the thrust bearing 43 therebetween.
As a result, when the high-pressure air P is supplied to the hollow air supply passage 50 of the thrust bearing 43, the high-pressure air P throttled by the injection holes 43a is sprayed to both thrust collars 51, and the thrust bearing 43 and both thrusts. The collar 51 is not in contact with the drive shaft 31 and is supported in the thrust direction.

In the turbocharger 1 of the present embodiment, the turbine blades 13 are disposed between the first partition plate 60 and the disk back surface 11 a of the turbine impeller 11 and at the insertion portion of the drive shaft 31 in the first partition plate 60. A seal is provided to prevent the exhaust gas (high-pressure fluid) from the fluid inlet T from entering the hollow portion B in the bearing housing 32.
Specifically, as shown in FIG. 3 in detail, a labyrinth seal 61 is formed on the surface facing the turbine impeller 11 side of the first partition plate 60 by an annular unevenness centered on the axis O, and A similar labyrinth seal 62 is formed at the insertion position of the drive shaft 31 in the one partition plate 60, thereby preventing the passage of gas in the gap between the first partition plate 60 and the disk back surface 11 a of the turbine impeller 11. .

  Further, between the second partition plate 70 and the disk back surface 21a of the compressor impeller 21, the compressed air (high-pressure fluid) at the fluid outlet C of the compressor blades 23 flows into the hollow portion B as shown in detail in FIG. A seal that prevents intrusion, that is, a labyrinth seal 71 is formed, and gas passage in the gap between the second partition plate 70 and the disk rear surface 21a of the compressor impeller 21 is prevented.

Next, operation | movement of the supercharger 1 which consists of said structure is demonstrated.
When the turbine impeller 11 is rotated by the relatively hot exhaust gas of the internal combustion engine, the rotational force is transmitted to the compressor impeller 21 through the drive shaft 31. The compressed air is supplied to the internal combustion engine as the compressor impeller 21 rotates. The rotational speed of the drive shaft 31 is, for example, tens of thousands to several hundred thousand rpm.

Further, in the supercharger 1 of the present embodiment, the high pressure air P is supplied to the air supply port 32a of the bearing housing 32 by the pressure device (not shown) along with the rotation of the turbine impeller 11.
First, as shown in FIG. 2, the high-pressure air P flows into the main air supply path 44a from the air supply port 32a and then spreads over the entire area of the main air supply path 44a, and the two radial bearings 42 are formed from the annular grooves 45a and 45b. And is supplied to the drive shaft 31 through the injection hole 42a. At the same time, the high-pressure air P in the main air supply path 44a reaches the hollow air supply path 50 of the thrust bearing 43 through the sub air supply path 44b and is supplied to the thrust collar 51 through the injection holes 43a.
As a result, the drive shaft 31 is supported in a non-contact manner in the radial direction by forming a fluid film by the high-pressure air P between the radial bearing 42 and the drive shaft 31 in the radial direction. A fluid film is formed between the thrust collar 51 and the high-pressure air P so that the thrust collar 51 is supported without contact.
In this way, the drive shaft 31 is supported by the hydrostatic air bearing 40 while maintaining a non-contact state without using lubricating oil. Therefore, it is possible to reduce bearing loss as compared with the case where lubricating oil is used as the lubricant, and it is possible to maintain a clean environment.

  Here, the supporting force of the drive shaft 31 by the hydrostatic air bearing 40 is supplied to the atmosphere in which the hydrostatic air bearing 40 is disposed, that is, the pressure of the hollow portion B in the bearing housing 32 and the hydrostatic air bearing 40. The pressure difference with the high-pressure air P to be generated becomes so large that it is remarkable. Therefore, when the pressure of the hollow part B where the static pressure air bearing 40 is disposed is high, the supporting force by the high pressure air P is impaired.

In contrast, in the turbocharger 1 of the present embodiment, the labyrinth seal 61 is formed on the surface of the first partition plate 60 on the turbine impeller 11 side, and the labyrinth seal 62 is formed at the insertion portion of the drive shaft 31 in the first partition plate 60. Therefore, the high-pressure exhaust gas at the fluid inlet T of the turbine blade 13 does not reach the hollow portion B, and the pressure difference between the fluid inlet T and the hollow portion B can be maintained.
Furthermore, since the labyrinth seal 71 is also formed on the surface of the second partition plate 70 on the compressor impeller 21 side, the compressed air at the fluid outlet C of the compressor blade 23 does not reach the hollow portion B, and the fluid outlet C And the pressure difference between the hollow portion B can be maintained.
Accordingly, the pressure of the hollow portion B that is in communication with the outside can be suppressed to about atmospheric pressure without being affected by exhaust gas or compressed air, and therefore the drive shaft 31 by the high-pressure air P in the static pressure air bearing 40. The drive shaft 31 can be supported efficiently and reliably without impairing the support force.

  Further, the presence of the labyrinth seals 61 and 62 as described above can prevent the dust of the exhaust gas that passes through the turbine housing 12 from entering the hollow portion B. Therefore, the environment around the hydrostatic air bearing 40 is clean. Thus, it is possible to avoid the occurrence of problems in the operation of the hydrostatic air bearing 40.

  Further, since the labyrinth seals 61, 62, 71 are employed as the seals, the seal configuration can be realized with a simple configuration, and the non-contact state between the turbine impeller 11 and the first partition plate 60 and the compressor impeller 21 can be realized. And the second partition plate 70 can be maintained in a non-contact state, and the impellers 11 and 21 can be prevented from slidingly contacting other members. Can be performed.

  Further, the thrust bearing 43 is disposed so as to be sandwiched between the pair of thrust collars 51, and the high pressure air P is jetted to both sides in the direction of the axis O toward the thrust collars 51. The position in the O direction is fixed in a floating state, and stable non-contact support in the axis O direction can be achieved.

  As mentioned above, although preferred embodiment of the supercharger which concerns on this invention was described referring drawings, it cannot be overemphasized that 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 present embodiment, the labyrinth seals 61 and 71 are used as the seal structure between the disk back surfaces 11a and 21a of the impellers 11 and 21 and the partition plates 60 and 70, but the present invention is not limited thereto. However, other seal structures may be employed.
Further, when the labyrinth seals 61 and 71 are employed, not only the case where the annular irregularities are formed only on the partition plates 61 and 71 as shown in FIGS. 3 and 4, but also the back surfaces of the disks of the impellers 11 and 21. 11a and 21a may be provided with similar annular irregularities and arranged so as to mesh with each other to further improve the sealing function.

  In the present embodiment, the thrust bearing 43 is sandwiched between the pair of thrust collars 51. On the contrary, the thrust bearing is connected to the high-pressure air from both axial sides of one thrust collar. It may be configured to inject P. This also enables stable non-contact support in the thrust direction.

1 is a side sectional view showing an overall configuration of a supercharger that is an embodiment of the present invention. FIG. 2 is an enlarged view of the vicinity of a hydrostatic air bearing in FIG. 1. FIG. 2 is an enlarged view of the vicinity of the rear surface of the turbine impeller in FIG. 1. FIG. 2 is an enlarged view of the vicinity of the back surface of the compressor impeller in FIG. 1.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Supercharger 10 Radial turbine 11 Turbine impeller 11a Disc back surface 12 Turbine housing 20 Compressor 21 Compressor impeller 21a Disc back surface 22 Compressor housing 30 Bearing part 31 Drive shaft 32 Bearing housing 40 Hydrostatic air bearing 42 Radial bearing 43 Thrust bearing 43a Injection hole 51 Thrust collar 60 First partition 61 Labyrinth seal 62 Labyrinth seal 70 Second partition 71 Labyrinth seal O Axis

Claims (3)

A turbine housing and a compressor housing are provided on both sides of the bearing housing, and a drive shaft that rotates about an axis is inserted into each of the housings. A turbine impeller is inserted into the drive shaft in the turbine housing. In the turbocharger provided with a compressor impeller on the drive shaft in the compressor housing,
A hydrostatic air bearing is provided in the bearing housing for supporting the drive shaft in a rotatable and non-contact manner around the axis,
A partition plate that divides the inside of each housing while being inserted through the drive shaft is disposed on the disk back side of each impeller, respectively.
A turbocharger characterized in that a seal is provided between the disk and the partition plate to prevent the high-pressure fluid of the turbine impeller and the compressor impeller from entering the bearing housing.   The supercharger according to claim 1, wherein the seal is a labyrinth seal. The hydrostatic air bearing includes a radial bearing that supports a radial direction of the drive shaft, and a thrust bearing that supports a thrust direction of the drive shaft,
The thrust bearing includes a disk-shaped thrust collar that rotates together with the drive shaft, and is disposed so as to face the axial direction, and includes injection holes that inject high-pressure air on both sides in the axial direction toward the thrust collar. The supercharger according to claim 1 or 2, wherein

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