JP2001140888A - Bearing device and turbocharger having the same - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To reduce the generation of air bubbles in an oil film damper, and to sequentially replace new lubricating oil with lubricating oil by generating a flow in a predetermined direction. To provide a bearing device and a turbocharger having a high damper effect. SOLUTION: A radial bearing 2a for supporting a rotating shaft 1 is provided.
2b, a bearing bush 3 provided with bearings 2a and 2b on the inner peripheral surface, and a housing 4, and lubricating oil is supplied to a gap 5 between the outer peripheral surface of the bearing bush 3 and the inner peripheral surface of the housing 4. In the bearing device having the lubricating oil supply ports 7a and 7b, the outer peripheral grooves 9a and 9b are formed on the outer peripheral surface of the bearing bush at positions corresponding to the supply ports 7a and 7b.
Oil passages 10a, 10b communicating with the sliding surfaces of the bearings 2a, 2b
b, and seals 12a and 12b for preventing leakage of lubricating oil are provided at positions on the shaft end side of the supply ports 7a and 7b.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bearing device used for a high-speed rotating machine or the like and a turbocharger having the same.

[0002]

2. Description of the Related Art An oil film damper bearing device is known as a bearing device for improving the rotational stability of a high-speed rotating machine such as a turbocharger. The oil film damper bearing reduces the amount of vibration of the shaft by dispersing the energy of the vibration of the rotating shaft through the oil film damper on the outer peripheral side of the bearing, and is thus effective in stabilizing the rotation of the shaft.

An oil film damper bearing device used in a small high-speed rotating machine is disclosed in, for example, JP-A-9-24.
As described in JP-A No. 2554, there is a type in which two bearings are integrated to form a bearing bush, and one oil film damper is formed on the outer peripheral side. The lubricating oil supply port is located at a position corresponding to the two bearings, an outer peripheral groove is formed in the bearing bush, and several oil passage holes are provided radially from the bottom of the outer peripheral groove. A part of the supplied lubricating oil is supplied to the bearing sliding surface, and the rest is supplied to the oil film damper. The lubricating oil flows in the oil film damper toward the shaft end and leaks and is discharged as it is. It flows through the inside in the axial center direction, and is discharged from an oil hole penetrating both the bearing bush and the housing.

[0004]

In the bearing device constructed as described above, cavitation is easily generated in the oil film damper due to the vibration of the bearing bush. When bubbles are generated by cavitation, the viscosity of the lubricating oil may be reduced and the effect of the damper may be reduced. However, no consideration has been given to such a case.

SUMMARY OF THE INVENTION An object of the present invention is to reduce the generation of bubbles in an oil film damper, and to replace a new lubricating oil with a lubricating oil in which bubbles are generated by giving the lubricating oil a flow in a predetermined direction. And to provide a bearing device having a high damper effect. Another object of the present invention is to provide a turbocharger which has a high damper effect by providing the above bearing device, and which does not cause white smoke of exhaust gas or adversely affect the environment. is there.

[0006]

In order to achieve the above object, a bearing device according to the present invention comprises a rotating shaft,
A radial bearing that supports the rotary shaft, a bearing bush provided with the radial bearing on the inner peripheral surface, and a housing that houses the bearing bush; In a bearing device having a lubricating oil supply port provided on a housing side for supplying lubricating oil to a gap between the bearing bushes and using the gap as an oil film damper, an outer periphery of a bearing bush at a position opposite to the lubricating oil supply port An outer peripheral groove is formed on the surface, an oil passage hole communicating with the sliding surface of the radial bearing is provided in the outer peripheral groove, and a seal for preventing leakage of lubricating oil is provided at a position on the shaft end side of the lubricating oil supply port, An oil hole that penetrates both the bearing bush and the housing is provided to give lubricating oil flow in the oil hole direction.

More specifically, the seal is a ring-shaped elastic seal. In order to achieve the above object, another aspect of the bearing device according to the present invention includes a rotating shaft, a radial bearing that supports the rotating shaft, a bearing bush provided with the radial bearing on an inner peripheral surface, A housing in which the bearing bush is accommodated, and a lubricating oil supply port provided on the housing side for supplying lubricating oil to a gap between an outer peripheral surface of the bearing bush and an inner peripheral surface of the housing, In the bearing device using the gap as an oil film damper, the central portion of the inner peripheral surface of the bearing bush sandwiched between the radial bearings is made larger in diameter than the inner diameter of the radial bearing, so that the rotation shaft and the central portion of the bearing bush are The interval is made larger than the radial bearing portion, and an outer peripheral groove is formed on the outer peripheral surface of the bearing bush at a position facing the lubricating oil supply port. An oil passage hole communicating with the moving surface is provided, a seal is provided at a position on the shaft end side of the lubricating oil supply port to prevent leakage of lubricating oil, and an oil hole penetrating both the bearing bush and the housing is provided at the center of the bearing bush. The lubricating oil is provided in the portion and the housing to give the lubricating oil a flow in the oil hole direction.

In order to achieve the above object, a bearing device according to another aspect of the present invention comprises a rotating shaft, a radial bearing for supporting the rotating shaft, and a bearing provided with the radial bearing on an inner peripheral surface. A bush and a housing in which the bearing bush is housed, and a lubricating oil supply port provided on the housing side for supplying lubricating oil to a gap between an outer peripheral surface of the bearing bush and an inner peripheral surface of the housing. In the bearing device using the gap as an oil film damper, the inner diameter of the bearing bush is constant, the diameter of the rotation shaft at the center portion sandwiched by the radial bearings is reduced, and the rotation shaft and the center portion of the bearing bush are The interval is made larger than the radial bearing portion, and an outer peripheral groove is formed on the outer peripheral surface of the bearing bush at a position facing the lubricating oil supply port. An oil passage is provided to the sliding surface of the bearing, a seal is provided at a position on the shaft end side of the lubricating oil supply port to prevent leakage of lubricating oil, and the oil hole passing through both the bearing bush and the housing is rotated. It is provided on the bearing bush and the housing corresponding to the small-diameter portion of the shaft to give lubricating oil a flow in the oil hole direction.

In order to achieve the above object, a bearing device according to another aspect of the present invention includes a rotating shaft, a radial bearing for supporting the rotating shaft, and a bearing provided with the radial bearing on an inner peripheral surface. A bush and a housing in which the bearing bush is housed, and a lubricating oil supply port provided on the housing side for supplying lubricating oil to a gap between an outer peripheral surface of the bearing bush and an inner peripheral surface of the housing. In a turbocharger having a bearing device using the gap as an oil film damper, an outer peripheral groove is formed on an outer peripheral surface of a bearing bush at a position corresponding to the lubricating oil supply port, and the outer peripheral groove is provided with the radial bearing. An oil hole communicating with the sliding surface, a seal for preventing leakage of lubricating oil is provided at a position on the shaft end side of the lubricating oil supply port, and the bearing bush and the housing are provided. The oil hole together through the provided are those comprising a bearing means for providing a flow of oil hole direction to the lubricating oil.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view of a turbocharger provided with an oil film damper bearing device according to the present invention, and FIG. 2 is a sectional view taken along line AA of FIG. As shown in FIG. 1, the rotating shaft 1 includes two radial bearings 2a.
And 2b. Although not shown, a turbine blade is attached to the left end of the rotating shaft 1 and a compressor blade is attached to the opposite right end. The radial bearings 2a and 2b are provided at both axial ends of the inner peripheral surface of the cylindrical bearing bush 3. Radial bearings 2a and 2 on the inner peripheral surface of bearing bush 3
The central portion sandwiched between b is larger in diameter than the inner diameters of the radial bearings 2a and 2b, and the interval between the rotating shaft 1 and the bearing bush 3 is larger than that of the radial bearings 2a and 2b. This is to suppress the loss due to the shearing of the lubricating oil in portions other than the radial bearings 2a and 2b.

Therefore, for example, the inner diameter of the bearing bush 3 is constant, and the distance between the rotating shaft and the bearing bush is made larger than that of the bearing part by reducing the diameter of the rotating shaft in the central portion between the bearings 2a and 2b. But they do the same. The outer peripheral surface of the bearing bush 3 is cylindrical, and is housed in a housing 4 also having a cylindrical inner peripheral surface. The left end of the bearing bush 3 is positioned by a retaining ring 20, and the right end is a thrust collar 1 fixed to the rotating shaft 1.
3, the axial movement of the bearing bush 3 is suppressed. The inner diameter of the housing 4 is slightly larger than the outer diameter of the bearing bush 3, and a gap 5 between the inner diameter of the housing 4 and the outer diameter of the bearing bush 3 forms an oil film damper. The housing 4 is provided with an oil passage 6 for guiding lubricating oil pressurized by an oil pump or the like installed outside. This oil passage 6
The housing 4 is connected to lubricating oil supply ports 7a and 7b provided on the inner peripheral surface.

At positions corresponding to the lubricating oil supply ports 7a and 7b on the outer peripheral surface of the bearing bush 3, outer peripheral grooves 9a and 9b are provided.
Are provided, but these outer peripheral grooves 9a and 9b correspond to the positions of the bearings 2a and 2b, respectively. The outer peripheral grooves 9 a and 9 b are provided with radial oil passage holes 10 a (three places in this embodiment) directed toward the inner peripheral surface of the bearing bush 3. Reference numeral 8 denotes an oil hole, and the bearing bush 3 and the housing 4
Are provided at the same position.

Ring grooves 11a and 11b are provided on the outer periphery of the bearing bush 3 on the side closer to the shaft end than the outer peripheral grooves 9a and 9b, and ring-shaped elastic seals 12a and 12b such as O-rings are provided. Installed. If the elastic seals 12a and 12b have a thickness corresponding to the interval of the gap 5, it is not always necessary to provide a ring groove. Further, the cross section does not need to be O-shaped, but may be square or another shape.

Next, the flow of the supplied lubricating oil will be described. In the following description, the lubricating oil flows in the left half of the figure, that is, the area indicated by the suffix a, but the description is omitted in the same manner in the right half of the figure, that is, the area indicated by the suffix b. The lubricating oil pressurized by an external pump (not shown) passes through the oil passage 6 and is supplied into the housing 4 from the lubricating oil supply port 7a. After a part of the supplied lubricating oil fills the outer peripheral groove 9a of the bearing bush 3, it is supplied to the sliding surface of the bearing 2a through the oil passage hole 10. Outer peripheral groove 9a
Has a depth that does not cause resistance, so that the oil pressure in the groove becomes constant. Therefore, the lubricating oil of the same pressure is supplied to the sliding surface of the bearing 2a over the entire circumference. The remaining portion of the supplied lubricating oil is the gap 5 on the shaft end side and the shaft center side with respect to the outer circumferential groove 9a.
Meet. The lubricating oil that has filled the gap 5 on the shaft end side has an elastic seal 12 if the ring groove 11a has no sealing ability.
a, and is discharged to the outside of the housing 4 from an oil discharge port (not shown) located below the figure. The lubricating oil filling the gap 5 on the shaft center side is discharged from the oil hole 8 and further discharged from the oil discharge port (not shown).

The rotating shaft 1 vibrates with rotation, and this vibration is generated by a radial bearing 2 which is a kind of spring damper system.
It is transmitted to the bearing bush 3 through the sliding surfaces a and 2b.
With the vibration of the bearing bush 3, the gap 5 between the bearing bush 3 and the housing 4 changes. When the gap 5 is narrowed, pressure is generated in the lubricating oil due to the squeeze effect, so that it acts as an oil film damper.

In this embodiment, the lubricating oil supplied from the lubricating oil supply ports 7a and 7b passes through the gap 5 and the oil hole 8
From the oil hole 8 or through the oil passage 8 and the sliding surface of the radial bearing. In both cases, since the gap amount is small and the resistance is large, the lubricating oil pressure increases in the outer peripheral grooves 9a and 9b according to the pressure of the external pump. Along with this, the outer peripheral groove 9a even in the gap 5
And 9b are highest and the oil pressure is lowest in the oil hole 8. Cavitation is generated when the lubricating oil pressure is lower than the saturated vapor pressure of the lubricating oil. Thus, by increasing the pressure in advance, the generation of bubbles due to cavitation can be suppressed or the generation of bubbles can be reduced.

Also, due to this pressure gradient, the lubricating oil containing no air bubbles from the external pump gives the lubricating oil a flow in the direction from the outer peripheral grooves 9a and 9b toward the oil hole 8. Outer peripheral groove 9
Since a and 9b are just inside the elastic seals 12a and 12b, this flow can always replace all the lubricating oil in the gap 5 or the oil film damper with a new one.

As described above, according to this embodiment, the generation of bubbles due to cavitation is reduced by increasing the pressure in the oil film damper, and the lubricating oil is given a flow toward the oil hole. This makes it possible to sequentially replace new lubricating oil with lubricating oil in which bubbles are generated, and to provide a bearing device having a high damper effect by an oil film. Further, since the resistance of the entire system is large, the required amount of the lubricating oil supplied to the oil film damper decreases. When the required oil amount decreases, the load on the external oil pump is reduced, which leads to an improvement in fuel efficiency of the entire system. Further, in the related art, the lubricating oil leaked from the gap may travel along the rotating shaft and mix with the process fluid. In particular, in the case of a turbocharger, mixing into the airflow of the turbine may cause white smoke in the exhaust gas or may have a bad influence on the environment. In the turbocharger equipped with the bearing device according to the present invention, the elastic body seal can prevent the leakage of the lubricating oil, so that the adverse effects such as white smoke of the exhaust gas and adversely affecting the environment are eliminated. can do.

[0019]

According to the present invention, the generation of bubbles in the oil film is reduced, and a new lubricating oil is always bubbled by applying a flow toward the oil hole for discharging the lubricating oil. Lubricating oil can be sequentially replaced, and a bearing device having a high damper effect by an oil film can be provided.

Further, by providing this bearing device, it is possible to provide a turbocharger which has a high damper effect and does not cause white smoke in the exhaust gas or adversely affect the environment.

[Brief description of the drawings]

FIG. 1 is a sectional view of a turbocharger including an oil film damper bearing device according to the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Rotating shaft 2a, 2b ... Bearing 3 ... Bearing bush 4 ... Housing 5 ... Gap 6 ... Oil passage 7 ... Lubricating oil supply port 8 ... Oil hole 9a, 9b ... Outer peripheral groove 10 ... Oil passage hole 11a, 11b ... Ring Grooves 12a, 12b Elastic seal 13 Thrust collar 20 Stop ring

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Tetsuo Udagawa 2520 Oaza Takaba, Hitachinaka-shi, Ibaraki F-term within the Hitachi, Ltd. Automotive Equipment Group (reference) 3G005 EA04 EA16 FA31 FA33 FA41 FA45 GB39 GB57 GB63 GB67 GB74 3J011 AA07 BA02 KA02 MA03 PA03

Claims (5)

[Claims] 1. A rotary shaft, a radial bearing for supporting the rotary shaft, a bearing bush provided with the radial bearing on an inner peripheral surface, and a housing for accommodating the bearing bush. A bearing device having a lubricating oil supply port provided on the housing side for supplying lubricating oil to a gap between the surface and an inner peripheral surface of the housing, wherein the gap is used as an oil film damper; An outer peripheral groove is formed on the outer peripheral surface of the bearing bush at a position facing the port, an oil passage hole communicating with the sliding surface of the radial bearing is provided in the outer peripheral groove, and a lubricating oil is provided at a position on the shaft end side of the lubricating oil supply port. A bearing device comprising: a seal that prevents leakage of oil; an oil hole that penetrates the bearing bush and the housing; and a flow of lubricating oil in a direction of the oil hole. 2. The bearing device according to claim 1, wherein the seal is a ring-shaped elastic seal. 3. A rotary shaft, a radial bearing for supporting the rotary shaft, a bearing bush provided on the inner peripheral surface of the radial bearing, and a housing for accommodating the bearing bush. A bearing device that has a lubricating oil supply port provided on the housing side to supply lubricating oil to a gap between the surface and the inner peripheral surface of the housing, and uses the gap as an oil film damper; The central portion of the inner peripheral surface sandwiched between the radial bearings is made larger in diameter than the inner diameter of the radial bearing, and the interval between the rotating shaft and the central portion of the bearing bush is made larger than the radial bearing portion. An outer peripheral groove is formed on an outer peripheral surface of the bearing bush at a position opposite to the outer peripheral groove, and an oil passage hole communicating with a sliding surface of the radial bearing is provided in the outer peripheral groove, and a shaft of the lubricating oil supply port is provided. A seal for preventing leakage of lubricating oil is provided at a position on the side, and an oil hole penetrating both the bearing bush and the housing is provided in the central portion of the bearing bush and the housing to give a flow of lubricating oil in the direction of the oil hole. A bearing device. 4. A rotary shaft, a radial bearing for supporting the rotary shaft, a bearing bush provided on the inner peripheral surface of the radial bearing, and a housing for accommodating the bearing bush. A bearing device that has a lubricating oil supply port provided on the housing side to supply lubricating oil to a gap between the surface and the inner peripheral surface of the housing, and uses the gap as an oil film damper; The inner diameter is constant, the diameter of the rotating shaft in the central part sandwiched by the radial bearings is reduced, the distance between the rotating shaft and the central part of the bearing bush is made larger than that of the radial bearing part, and the position of the position facing the lubricating oil supply port is reduced. An outer peripheral groove is formed on the outer peripheral surface of the bearing bush, and an oil passage hole communicating with the sliding surface of the radial bearing is provided in the outer peripheral groove. A seal for preventing leakage of lubricating oil is provided, and an oil hole penetrating both the bearing bush and the housing is provided in the bearing bush and the housing corresponding to the small-diameter portion of the rotary shaft, and a flow of lubricating oil in the oil hole direction is provided. A bearing device characterized by the above-mentioned. 5. A rotary shaft, a radial bearing for supporting the rotary shaft, a bearing bush provided on the inner peripheral surface of the radial bearing, and a housing for accommodating the bearing bush. A turbocharger having a lubricating oil supply port provided on the housing side for supplying lubricating oil to a gap between the surface and an inner peripheral surface of the housing, and a bearing device using the gap as an oil film damper; An outer peripheral groove is formed on the outer peripheral surface of the bearing bush at a position opposite to the lubricating oil supply port; an oil passage hole communicating with a sliding surface of the radial bearing is provided in the outer peripheral groove; A seal device for preventing leakage of lubricating oil is provided at a position, an oil hole penetrating both the bearing bush and the housing is provided, and a lubricating oil is provided in the oil hole direction. Turbocharger, characterized by comprising.