JPH0571358A - Bearing device of turbocharger - Google Patents

Abstract

PURPOSE:To reduce the generation of noise by forming a treble oil film between outer and inner bearings and between the inner bearing and a shaft. CONSTITUTION:A bearing device has a bearing housing 11b and a shaft 13 is rotatably supported through a support means. The support means has a cylindrical outer bearing 26 and a plurality of cylindrical bearings 31 located inside the outer bearing. Oil films are formed in a gap between a bearing housing 11b and the outer bearing 26 and a gap between the inner bearing 31 and the shaft 13 by means of an oil feed hole 26a, an oil feed hole and an oil feed passage 29. The generation of vibration in a radial direction is reduced and the generation of noise is reduced by means of the treble oil film.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a turbocharger bearing device.

[0002]

2. Description of the Related Art As a conventional technology of a bearing device for a turbocharger, there is one disclosed in, for example, Japanese Patent Laid-Open No. 56-138423.

This prior art will be described with reference to FIG. 8. A bearing housing 71 of a turbocharger rotatably supports a shaft 73 via a radial bearing 72, and also two radial bearings 72.
An intermediate sleeve 74 is arranged between the two. Lubricating oil is supplied to each radial bearing 72 from an oil supply source (not shown) through an oil supply passage 75 formed in the bearing housing 71.

Accordingly, oil is pumped into a gap of several tens of microns formed between the radial bearing 72 and the shaft 73 rotating at a high speed, and an oil film is formed in this gap, so that the shaft 73 is a radial bearing. It rotates in a floating form on 72. At this time, the radial bearing 7
2 is dragged by the rotation of the shaft 73 through the oil film, and rotates around at a rotational speed of 20 to 30% of the rotational speed of the shaft. An oil film is also formed in the gap between the bearing housing 71 and the radial bearing 72.

As a result, the relative speed of the sliding surface between the radial bearing 72 and the shaft 73 decreases, and the whirling of the shaft 73 is suppressed by the damper effect of the oil film. It is possible to stably take charge of rotation without burning even during rotation.

[0006]

However, the vibration damping effect of the shaft 71 is not sufficient only with the oil film formed on the inner and outer peripheral surfaces of the radial bearing as described above. Therefore, in a passenger car turbocharger that requires quietness, the rotational vibration of the shaft 73 is transmitted to the bearing housing 71 via the radial bearing 72, and the rotational vibration of the radial bearing 72 itself is transmitted to the bearing housing 71. Has occurred, which is a problem.

Therefore, in the present invention, the technical problem is to reduce the noise of the turbocharger.

[0008]

[Constitution of the invention]

[0009]

The technical means of the present invention taken to solve the above-mentioned technical problems of the present invention include a housing and a shaft rotatably supported by the housing via a supporting means. , A thrust bush which is disposed on the shaft and which forms a housing portion, a thrust bearing which is fixed to the housing and which engages with the housing portion, and which is formed inside the housing, and which is formed in the housing, is configured to apply oil to the bearing means and the thrust bearing. In a turbocharger having an oil supply passage for supplying and a turbine rotor and a compressor rotor fixed to both ends of the shaft, the support means has an outer peripheral surface engaging with the housing through an oil film, and the housing and the rotation preventing member. At least one outer bearing that cannot be rotated relative to each other, and the outer peripheral surface is the inner peripheral surface of the outer bearing. The inner bearing is engaged with an oil film, and the inner peripheral surface is composed of a shaft and at least one inner bearing engaged with the oil film. Through holes are formed in the outer bearing and the inner bearing in the radial direction. That's what I did.

[0010]

According to the above-mentioned technical means of the present invention, the thrust bearing is arranged in the accommodating portion formed by the thrust bush, and the oil is supplied thereto to form the oil film. Axial vibration is suppressed. The shaft is supported by double outer and inner bearings, and radial vibrations are suppressed by the oil film formed between the housing and the outer bearing, the outer bearing and the inner bearing, and the inner bearing and the shaft. .. Especially, since the outer bearing cannot rotate relative to the housing, it does not give extra rotational vibration to the housing. Therefore, the axial and radial vibrations of the shaft are suppressed, so that the noise of the turbocharger can be reduced.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments embodying the technical means of the present invention will be described below with reference to the accompanying drawings.

In the turbocharger bearing device 10 of the first embodiment of the present invention shown in FIGS. 1 to 4, the housing 1 is used.
1 comprises a turbine housing 11a, a bearing housing 11b and a compressor housing 11c. A shaft 13 is rotatably supported by the bearing housing 11b via a support means 12, and a turbine rotor 14 is fixed to one end of the shaft 13 in the turbine housing by welding or the like. Further, a compressor rotor 17 is fixedly installed by a nut 18 at the other end of the shaft shaft 13 in the compressor housing 11c with thrust bushes 15, 16 interposed therebetween. The turbine housing 11a and the bearing housing 11b
With the coupling 19, the bearing housing 1
1b and the compressor housing 11c are integrally fixed by a bolt 20.

A heat insulator 21 is provided between the rear surface of the turbine rotor 14 and the bearing housing 11b.
And an oil leakage prevention mechanism 22 is formed in the vicinity of a fixed portion between the shaft 13 and the turbine rotor 14.

Similarly, an oil leakage prevention mechanism 23 is formed on the back surface of the compressor rotor 17. In FIG. 2, the housing 2 is provided between the thrust bushes 15 and 16.
4 is formed, and a part of the bearing housing 11b is formed.
The inner peripheral portion of the thrust bearing 25 fixed to the above is engaged in the accommodating portion 24 with a slight gap in the axial direction. It should be noted that the thrust bearing 25 is supplied with oil from an oil supply passage 29a formed in the bearing housing 11b.

In the bearing means 12, the outer peripheral surface of the cylindrical outer bearing 26 is the bearing housing 1
It is inserted with a slight gap from the inner wall surface of the housing portion 27 formed in 1b, and the rotation preventing member 28 shown in FIG. 3 prevents relative rotation with the bearing housing 11b, and the movement thereof in the axial direction. It is regulated. A plurality of oil supply holes (through holes) 26a are formed in the radial direction on the upper side of the outer bearing 26, and communicate with the oil supply passage 29 described above. The rotation preventing member 28 may be arranged at any position in the axial direction of the outer bearing 26. On the other hand, an oil drain hole (through hole) 26b is bored in the lower side of the outer bearing 26 in the radial direction, and the oil drain hole 3 is formed in the bearing housing 11b.
It communicates with 0.

Similarly, a plurality of cylindrical inner bearings 31 are inserted inside the outer bearing 26, and the inner peripheral surface of the outer bearing 26 and the inner bearing 3 are inserted.
There is a slight gap between the outer peripheral surface of No. 1 and the outer peripheral surface of No. 1. Figure 4
As shown in FIG. 5, the inner bearing 31 also penetrates in the radial direction and communicates with the oil supply hole 26a.
Although a is formed, this oil supply hole 31a completely penetrates the inner bearing in the radial direction, not halfway. Further, a half-moon shaped groove 26c is formed in the connecting portion of the oil supply hole 26a.

The shaft 13 is inserted in the inner peripheral surface of the inner bearing 31 with a slight gap.
In addition, the movement restriction of the inner bearing 31 in the axial direction is as follows.
It is performed by the thrust bush 15, the snap ring 32, and the step portion of the shaft 13.

The operation of the first embodiment of the present invention having the above construction will be described below.

An exhaust pipe of an engine (not shown) is connected to the turbine housing 11a, and when the exhaust gas flows into the interior, the turbine rotor is rotated by the energy of the exhaust gas, and the compressor rotor 17 is rotationally driven via the shaft 13. To do. Then, the fresh air (air) flowing into the compressor housing 11c is supercharged to the engine.

With the operation of the engine, oil is constantly fed under pressure from an oil source (not shown) to the oil supply passage 29, and is supplied to the vicinity of the thrust bearing 25 and the support means 12 to form and hold an oil film on each part. There is.

That is, first, in the vicinity of the thrust bearing 25, between the illustrated left side surface of the thrust bush 15 and the illustrated right side surface of the thrust bearing 25, and between the illustrated right side surface of the thrust bush 16 and the illustrated left side surface of the thrust bearing 25. An oil film is formed and held between them. Therefore,
When the shaft 13 rotates at a high speed, it vibrates in the axial and radial directions, respectively, but the axial vibration of the shaft 13 is reduced by the squeeze film effect (damper effect of oil) of the oil film, and the vibration is transmitted to the bearing housing 11b. The amount is kept to a very low level.

On the other hand, in the support means 12, a third oil film is formed in the gap between the bearing housing 11b and the outer bearing 26, a second oil film is formed in the gap between the outer bearing 26 and the inner bearing 31, and the inner bearing 31 and the shaft 13 are arranged. The first oil films are formed in the gaps between and. Therefore, the radial vibration of the shaft 13 is damped to some extent by the squeeze film effect in the first oil film.
Then, the shaft 1 transmitted to the inner bearing 31
The radial vibration of No. 3 and the rotational vibration of the inner bearing 31 itself, which circulates with the shaft 14, are attenuated by the second oil film,
At the same time, it is also damped by the third oil film. Therefore, the radial vibration of the shaft 13 is sufficiently damped by the triple oil film, and the amount of transmission to the bearing housing 11b is suppressed to a very small level. Also, the outer bearing 2
Since 6 is restricted from rotating relative to the bearing housing 11b, the addition of the outer bearing 26 does not serve as a new vibration source.

Next, a turbocharger bearing device 50 according to a second embodiment of the present invention will be described with reference to FIG. 5. The same components as those of the first embodiment are designated by the same reference numerals as those of the first embodiment. The description is omitted. The operation is also substantially the same as that of the first embodiment, and the description is omitted.

Here, the outer bearing 26 in the first embodiment is divided into two outer bearings 51 and 52, which are respectively engaged with the bearing housing 11b by a rotation preventing member 28 as shown in FIG.

Next, a turbocharger bearing device 60 of a third embodiment of the present invention will be described with reference to FIG. 7. The same components as those of the first embodiment will be designated by the same reference numerals as those of the first embodiment. The description is omitted. The operation is also substantially the same as that of the first embodiment, and the description is omitted.

Here, the two inner bearings 31 in the first embodiment are made into a single inner bearing 61, and a through hole 62 communicating with the oil drain holes 26b, 30 is formed in the central portion in the axial direction thereof. In this case, the snap ring 32 becomes unnecessary.

[0027]

As described above, according to the present invention, the thrust bearing is arranged in the accommodating portion formed by the thrust bush, and the oil is supplied to the thrust bearing to form the oil film. Axial vibration is suppressed. The shaft is supported by double outer and inner bearings, and radial vibrations are suppressed by the triple oil film formed between the housing and outer bearing, the outer bearing and inner bearing, and the inner bearing and shaft. Shaken.
Especially, since the outer bearing cannot rotate relative to the housing, it does not give extra rotational vibration to the housing. Therefore, the axial and radial vibrations of the shaft are sufficiently dampened and the amount of transmission to the bearing housing is suppressed, so that the noise of the turbocharger can be reduced.

[Brief description of drawings]

FIG. 1 is a sectional view of a bearing device for a turbocharger according to a first embodiment of the present invention.

FIG. 2 shows an enlarged cross-sectional view of a main part in FIG.

FIG. 3 is a sectional view taken along line AA in FIG.

FIG. 4 is a sectional view taken along line BB in FIG.

FIG. 5 is an enlarged sectional view of an essential part of a bearing device for a turbocharger according to a second embodiment of the present invention.

FIG. 6 is a sectional view taken along line CC of FIG.

FIG. 7 is an enlarged sectional view of an essential part of a bearing device for a turbocharger according to a third embodiment of the present invention.

FIG. 8 is an enlarged cross-sectional view of a main part of a conventional bearing device for a turbocharger.

[Explanation of symbols]

 10, 50, 60 turbocharger bearing device, 11 housing, 12 bearing means, 13 shaft, 14 turbine rotor, 15, 16 thrust bush, 17 compressor rotor, 24 accommodating portion, 25 thrust bearing, 26, 51, 52 outer Bearings, 26a, 31a Oil supply holes (through holes), 29 Oil supply passages, 31, 61 Inner bearings.

Claims (1)

[Claims] 1. A housing, a shaft rotatably supported by the housing via a bearing, a thrust bush disposed on the shaft and forming a housing, and fixed to the housing. At the same time, a thrust bearing that engages with the accommodating portion, an oil supply path that is formed inside the housing and that supplies oil to the support means and the thrust bearing, and a turbine rotor and a compressor that are fixedly installed at both ends of the shaft, respectively. In a turbocharger having a Tsusa rotor, the support means includes at least one outer bearing whose outer peripheral surface engages with the housing via an oil film and which is non-rotatable relative to the housing via an anti-rotation member. Surface engages with the inner peripheral surface of the outer bearing via an oil film, and the inner peripheral surface forms the shaft. It is composed of at least one of the inner bearing engages through the membrane, bearing device Tabochiyajiya wherein the outer bearing and the through holes respectively radially inner bearing is drilled.