JPH1150854A - Supercharger bearing support device for exhaust gas turbine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively cool a bearing stand by leading seal air inside the bearing stand, and coupling a bearing fitting case and the bearing stand with a plurality of ribs in a bearing support device formed by fitting the bearing supporting a rotor to a bearing fitting case coupled with the bearing stand. SOLUTION: In an exhaust gas turbine supercharger used for a diesel engine, a bearing fitting case 7 is integrally formed with a bearing stand 1, and a bearing supporting a rotor is fitted to the bearing fitting case 7. The bearing fitting case 7 is integrally coupled with the bearing stand 1 with ribs 19a to 19c so as to be integrated as a casting. A seal air escaping tube is fitted to the upper portion of the bearing stand 1, an air path connecting a inside space 23 and the seal air escaping tube is formed at a place corresponding to the seal air escaping tube of the bearing stand 1. Seal air is led to the inside space 23, and the inner wall face of the bearing stand 1 is cooled by the seal air so that the temperature rise of the bearing stand 1 is suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bearing support device for an exhaust gas turbocharger used in a diesel engine.

[0002]

2. Description of the Related Art FIGS. 5 to 7 show an example of a radial turbine type exhaust gas turbocharger (hereinafter referred to as a "supercharger") used in a large diesel engine. FIG. sectional view taken along, 6 B ₁ -B ₁ line sectional view of FIG. 5, FIG. 7 is a B ₂ -B ₂ sectional view taken along line of FIG.

5 to 7, reference numeral 4 denotes a turbine wheel, reference numeral 12 denotes an impeller of a compressor, and reference numeral 21 denotes a rotor connecting the turbine wheel 4 and the impeller 12. Reference numeral 2 denotes a gas casing on the turbine side, 31 denotes a compressor casing, and 1 denotes a bearing stand. The bearing stand 1 has front and rear ends thereof connected to the gas casing 2 and the compressor casing 31, respectively.

Reference numerals 6a and 6b denote bearings for supporting the rotor 21 at two positions near the turbine wheel 4 and near the impeller 12. Reference numerals 7, 7 denote bearing mounting cases to which the bearings 6a, 6b are mounted. As shown in FIGS.
It is integrally connected to the bearing base 1.

[0005] Reference numeral 15 denotes a cooling water chamber formed inside the bearing base 1, and as shown in Fig. 6, bearings 6a and 6b are provided.
Cooling water 17 for cooling the portion flows. 3
Is a heat transfer buffer chamber formed in the bearing base 1 at a position near the turbine wheel 4, and 23 is an internal space of the bearing base 1.
Reference numeral 25 denotes an exhaust gas passage formed in the gas casing 2, reference numeral 22 denotes a nozzle (stationary blade), reference numeral 18 denotes a seal gas passage provided on the back of the turbine wheel 4, and reference numeral 18a denotes a back of the impeller 12. Seal gas passage.

During operation of the supercharger, high-temperature exhaust gas from a diesel engine (not shown) flows through the exhaust gas passage 25 of the gas casing 2 and enters the nozzle 22 as shown by an arrow in FIG. The nozzle 22 is ejected from the nozzle 22 toward the turbine wheel 4. By rotating the nozzle 22, it performs expansion work and is discharged to an exhaust pipe. The rotation of the turbine wheel 4 is transmitted to an impeller 12 via a rotor 21. The impeller 12 compresses air taken in from the outside and sends the compressed air to an engine via an air cooler (not shown).

In the above-described radial turbine type turbocharger, a gas casing 2 through which high-temperature and high-pressure exhaust gas flows and a bearing base 1 supporting the bearings 6a and 6b via bearing mounting cases 7, 7 are provided. Since they are tightened by bolts and are in contact with each other, heat from the gas casing 2 heated by the exhaust gas is transmitted to the bearing stand 1. This heat is transmitted to the bearing mounting cases 7, 7 integrally fixed to the bearing base 1, and further transmitted through the bearing mounting cases 7, 7.
a, 6b to heat the bearings 6a, 6b.

Conventionally, in order to prevent the bearings 6a, 6b from overheating, heat transmitted from the gas casing 2 to the bearing mounting cases 7, 7 via the bearing base 1 is conventionally used.
As shown in FIG. 6, the heat transfer area is reduced by reducing the heat conduction area by the heat transfer buffer chamber 3 provided inside the cooling water chamber 15, and the cooling water chamber 15 is provided inside the bearing base 1. The cooling water 17 flows and circulates to cool the bearing base 1 and the bearing mounting cases 7, 7, thereby reducing the amount of heat transmitted to the bearings 6a, 6b.

[0009]

As described above, in the conventional turbocharger, the amount of heat transmitted to the bearings 6a and 6b is reduced to prevent the bearings 6a and 6b from being overheated. 1 is provided with a cooling water chamber 15 through which the cooling water 17 flows.
The structure becomes complicated, and the production cost is increased due to an increase in the number of steps in casting and the like. Further, in such a conventional apparatus, it is necessary to provide a pipe for supplying the cooling water 17 to the cooling water chamber 15, and the structure is further complicated by an increase in the number of pipes, and leakage of cooling hydrogen is reduced. It is easy to occur, it takes time for maintenance, and further increases the cost.

An object of the present invention is to reduce the amount of heat transmitted from a bearing stand to a bearing via a bearing mounting case in an exhaust gas turbocharger without providing cooling means by cooling water, and to provide a simple structure. An object of the present invention is to provide a low-cost bearing support device that does not require man-hours for maintenance.

[0011]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and its gist is to connect a bearing mounting case to a bearing stand provided between a turbine casing and a compressor casing. An exhaust gas turbine supercharger having a bearing for supporting a rotor for coupling a turbine wheel and an impeller of a compressor mounted on the bearing mounting case. A bearing support device for an exhaust gas turbine turbocharger, wherein a mounting case and a bearing base are connected by a plurality of ribs.

According to the above means, the seal air is guided to the inner space of the bearing stand, and the inner wall surface of the bearing stand is cooled by the seal air, whereby the temperature rise of the bearing stand is suppressed. Since the rib is connected to the bearing mounting case by a rib with a small cross-sectional area, the heat conduction area of the rib that serves as a heat transfer path from the bearing base to the bearing mounting case is reduced, and the amount of heat transfer to the bearing mounting case and bearing is reduced. Is done. This eliminates the need for cooling with cooling water as in the prior art, and eliminates the need for a cooling water chamber and cooling water supply piping.
The temperature of the bearing can be kept low.

In addition to the above-mentioned means, it is also a preferred embodiment of the present invention that an annular radiation blocking plate is mounted on the surface of the bearing stand facing the turbine wheel. According to this structure, the radiation blocking plate blocks the radiant heat from the high-temperature turbine wheel, and the bearing box can be prevented from being heated by the radiant heat.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIGS.
The embodiment will be described in detail. FIG. 1 shows an embodiment of the present invention.
Exhaust gas turbine supercharger for diesel engine according to form
Sectional view and figure along the rotor axis of the turbocharger
2 is an enlarged view of a main part of this, FIG. 3 is A in FIG. ₁-A₁Line cross section
FIG. 4 is a diagram of FIG._Two-A_TwoIt is a line sectional view.

1 to 4, reference numeral 4 denotes a turbine wheel, 12 denotes an impeller of a compressor, and 21 denotes a rotor for connecting the turbine wheel 4 and the impeller 12. Reference numeral 2 denotes a gas casing on the turbine side, reference numeral 31 denotes a compressor casing, and reference numeral 1 denotes a bearing stand formed of a cast product. . 25 is an exhaust gas passage formed in the gas casing 2, 22 is a nozzle (stationary vane), 1
Reference numeral 8 denotes a seal gas passage provided on the back of the turbine wheel 4, and reference numeral 18a denotes a seal gas passage provided on the back of the impeller 12. The above configuration is the same as the conventional supercharger shown in FIGS.

In the embodiment of the present invention, the bearing support device including the bearing stand and the bearing support case of the exhaust gas turbine turbocharger is improved. That is, in FIGS.
Reference numerals 6a and 6b denote bearings for supporting the rotor 21 at two positions near the turbine wheel 4 and near the impeller 12. 2
Reference numeral 3 denotes an internal space formed inside the bearing base 1 and in which lubricating oil and seal air after bearing lubrication flows or is temporarily stored. Reference numerals 8 and 8 denote oil labyrinths for oil sealing provided between the bearing 6a and the turbine wheel 4 and between the bearing 6b and the impeller 12, and 3 denotes a portion of the bearing base 1 near the turbine wheel 4. The formed heat transfer buffer chamber.

Reference numerals 7 and 7 are bearing support cases to which the bearings 6a and 6b are attached. The bearing support cases 7, 7
As shown in FIG. 4, a plurality of (three in this example) ribs 19a, 19b, and 19c are connected to the bearing base 1, and the bearing base 1 and the bearing support cases 7, 7
This constitutes a cast product integrated through 9a, 19b, and 19c. Reference numeral 13 denotes a seal air vent pipe, which is attached to an upper portion of the bearing base 1. As shown in FIG. 3, an air passage 26 connecting the internal space 23 and the seal air release pipe 13 is formed at a position of the bearing base 1 corresponding to the seal air release pipe 13.
Inside the air passage 26, a rib 20 for guiding a seal air to be connected to the rib 19a is formed.

Reference numeral 5 denotes an annular radiation blocking plate fixed to the bearing base 1 with bolts. The radiation blocking plate 5 is attached to a portion of the bearing base 1 corresponding to the back of the turbine wheel 4 so as to block radiant heat from the turbine wheel 4.

During the operation of the supercharger, high-temperature exhaust gas from a diesel engine (not shown) is supplied to the exhaust gas passage 25 of the gas casing 2 as shown by an arrow in FIG.
Flows into the nozzle 22 and is ejected from the nozzle 22 toward the turbine wheel 4. By rotating the nozzle, it performs expansion work and is discharged to the exhaust pipe. The rotation of the turbine wheel 4 is transmitted to an impeller 12 via a rotor 21. The impeller 12 compresses air taken in from the outside and sends the compressed air to an engine via an air cooler (not shown).

During the operation of the supercharger, heat from the gas casing 2 heated by the exhaust gas is transferred to the bearing stand 1.
Is transmitted to This heat is reduced by reducing the heat conduction area by the heat transfer buffer chamber 3 provided inside the bearing base 1.
Heat transfer to bearing support cases 7, 7 and bearings 6a, 6b described below is reduced.

On the other hand, as described above, there are a plurality of bearing mounting cases 7, 7 for supporting the bearings 6a, 6b (3 in this example).
Are connected to the bearing housing 1 by the ribs 19a, 19b, 19c and 20. Therefore, the inside of the bearing stand 1 is provided outside the bearing mounting cases 7, 7 with the ribs 19a, 19b, 1
An internal structure of a double structure in which the bearing base 1 is connected and arranged via 9c and 20 is provided, and the surface area of the inner surface of the bearing base 1 in contact with air increases.

During operation of the supercharger, the lubricating oil passage 1
1 so that the lubricating oil supplied to the bearings 6a and 6b through the oil labyrinth 8 which controls the leakage of the lubricating oil to the outside of the bearing stand does not leak outside. Since the seal air 9 is supplied from the seal air passage 18 to the internal space 23, the internal space of the bearing base 1 is filled with the seal air 9, and the pressure in the internal space of the bearing base 1 increases. However, in this embodiment, since the seal air vent pipe 13 for discharging the seal air 9 to the outside of the bearing base is attached to the bearing base 1,
The pressure rise is reduced. Therefore, a flow of seal air is generated inside the bearing stand.

On the other hand, the amount of heat transmitted from the gas casing 2 moves from the bearing base 1 to the bearing mounting case 7 via the ribs 19a to 19c, and raises the temperature of the inner wall of the bearing base 1. In order to reduce the temperature rise of the wall surface, in this embodiment, as shown in FIG. 2, the sealing air 9 released to the outside is guided to the internal space 23 of the bearing base 1 as cooling air, and Inner wall and seal air 9
The amount of heat flowing into the inner wall of the bearing base 1 is recovered by the flow of sealing air in the internal space 23 by increasing the contact area with the inner space. Therefore, from the gas casing 2 to the bearing stand 1
Is transmitted from the inner wall surface of the bearing base 1 to the seal air 9, and the heat is consumed by increasing the temperature of the seal air 9. The seal air 9 whose temperature has been increased in this way is discharged to the outside of the bearing base 1 through the seal air vent pipe 13. Due to such an action, the transfer of heat from the bearing base 1 to the bearing mounting case 7 is reduced.

Further, in this embodiment, a plurality of ribs 1 having a small cross-sectional area
Since the ribs 19a, 19b, 19c, and 20 are connected to the ribs 19a, 19b, 19c, and 20 as heat transfer paths from the bearing base 1 to the bearing mounting cases 7, 7, the heat conduction cross-sectional area is small. Bearing mounting cases 7, 7 and bearing 6
a, the amount of heat transfer to 6b is reduced. By such an operation, the bearings 6a and 6 can be cooled without cooling with cooling water.
The temperature of b can be kept low.

The turbine wheel 4 exposed to the high-temperature exhaust gas also has a high temperature.
Is radiated to the bearing base 1. In this embodiment, the radiation heat is blocked by a radiation blocking plate 5 provided on the back of the turbine wheel 4, and the temperature rise of the bearing housing 1 due to the radiated heat is suppressed. Restrained. Since the radiation shielding plate 5 is cooled by the seal air 9,
The temperature rise itself is suppressed.

[0026]

The present invention is configured as described above.
ADVANTAGE OF THE INVENTION According to this invention, it can suppress the temperature rise of a bearing stand by guide | inducing a seal air to the inside of a bearing stand, and cooling the inner wall of a bearing stand, Furthermore, a bearing stand and a bearing mounting case have a cross-sectional area. Because they are joined by small ribs
The heat conduction area of the rib serving as a heat transfer path from the bearing stand to the bearing mounting case is reduced, and the amount of heat transfer to the bearing mounting case and the bearing is reduced. As a result, the temperature of the bearing can be kept low without requiring cooling with cooling water as in the conventional case, and it is not necessary to provide a cooling water chamber inside the bearing stand as in the conventional case, and The structure of the stand is simplified, and piping for supplying cooling water is not required, so that a low-cost bearing support device with a simple structure can be obtained.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view taken along a rotor axis of an exhaust gas turbine turbocharger for a diesel engine according to an embodiment of the present invention.

FIG. 2 is an enlarged sectional view of a main part (bearing supporting part) of FIG.

FIG. 3 is a sectional view taken along line A ₁ -A _{1 of} FIG. ₁ ;

FIG. 4 is a sectional view taken along line A ₂ -A ₂ of FIG. 1;

FIG. 5 is an equivalent view of FIG. 1 showing a conventional exhaust gas turbine supercharger.

FIG. 6 is a sectional view taken along line B ₁ -B ₁ of FIG. 5;

FIG. 7 is a sectional view taken along line B ₂ -B _{2 in} FIG. 5;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Bearing stand 2 Gas casing 3 Heat transfer buffer room 4 Turbine wheel 5 Radiation blocking plate 6a, 6b Bearing 7 Bearing mounting case 8 Oil labyrinth 9 Seal air 11 Lubricating oil passage 12 Impeller 13 Seal air vent pipe 18, 18a Seal air passage 19a , 19b, 19c Rib 20 Rib 21 Rotor 22 Nozzle 23 Internal space 25 Exhaust gas passage 26 Air passage 31 Compressor casing

Continued on the front page (72) Inventor Yukihiro Iwasa 1-1, Akunouracho, Nagasaki-shi, Nagasaki Shipyard, Mitsubishi Heavy Industries, Ltd.

Claims (1)

[Claims] 1. A bearing mounting case is connected to a bearing stand provided between a turbine casing and a compressor casing,
In the exhaust gas turbine turbocharger, in which a bearing for supporting a rotor that couples a turbine wheel and a compressor impeller is mounted on the bearing mounting case, a seal air is introduced into the bearing base, and the bearing mounting is performed. A bearing support device for an exhaust gas turbine turbocharger, wherein a case and a bearing stand are connected by a plurality of ribs.