JP2001303964A - Turbocharger bearing structure - Google Patents

Abstract

(57) [Problem] To reduce the vibration generated during rotation of a turbine shaft of a turbocharger by reducing the weight of an oil film damper supported from the periphery of a ball bearing of the turbine shaft in a turbine shaft penetration portion of a bearing housing. In addition to reducing the noise, the generation of the noise is also suppressed. In a turbocharger bearing structure in which a turbine housing (1) and a compressor housing (2) are integrally connected via a bearing housing (3), journal bearings (3a) are provided at both ends in the axial direction within a turbine shaft penetration portion of the bearing housing (3). It is made of a heat-resistant synthetic resin material having a substantially cylindrical shape and inserted into the outer diameter of each of the ball bearings 25 and 26 in order to absorb the vibrations of the fitted ball bearings 25 and 26. And an oil film damper 27.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bearing structure of a turbocharger, and more particularly to a bearing structure of a turbocharger in which an oil film damper is interposed in a ball bearing serving as a bearing of a turbine shaft to reduce the vibration thereof. It is about.

[0002]

2. Description of the Related Art A conventional turbocharger bearing structure includes:
As shown in the side sectional view of FIG. 3, the turbine housing 1 and the inside of the compressor housing 2 are integrally connected via a bearing housing 3. In this turbocharger, a turbine wheel 4 in a turbine housing 1 and a compressor wheel 5 in a compressor housing 2 are connected by a turbine shaft 6 rotatably supported by journal bearings in a bearing housing 3. . In the bearing structure of the turbocharger, the turbine wheel 4 is rotated by the exhaust of the engine to rotate the compressor wheel 5 via the turbine shaft 6 to compress the intake air and supply the engine with air.

[0003] The turbine shaft 6 of the turbocharger is
In order to rotate at high speed, it is necessary to lubricate the journal bearing 3a, and a bearing fitting wheel 8 having an oil supply passage 7 in the circumferential direction and the radial direction is incorporated in the turbine shaft penetration portion of the bearing housing 3, and this bearing fitting ring 8 Floating metals 9 and 1 having oil supply holes 11 in the radial direction at both axial ends
0 is rotatably fitted as a journal bearing 3a, and lubricating oil O supplied through an oil supply passage 12 provided in the bearing housing 3 is guided to the inner and outer peripheral surfaces of the floating metals 9, 10.

An oil drain 15 having an uneven surface is provided on the outside of the turbine shaft 6 on which the compressor wheel 5 is mounted in the compressor housing 2.
6, a seal plate 17 whose inner peripheral surface is in contact with the compressor-side sealing 16 is attached to the bearing housing 3 to form an oil seal portion. Further, a thrust bearing 18 provided with a dedicated oil supply passage 19 communicating with the oil supply passage 13 of the bearing housing 3 is disposed between the oil drain 15 and a surface of the thrust bush 14 on the compressor side. Is a positive thrust (thrust in a direction in which the turbine shaft 6 moves toward the compressor) bearing surface, and a surface of the oil drain 15 on the turbine side is an anti-thrust (a direction in which the turbine shaft 6 moves toward the turbine). Of the thrust bearing 18.
Is lubricated by the lubricating oil O coming out of the dedicated oil supply passage 19 of the first embodiment. The lubricating oil O is supplied to the oil drain hole 20 of the bearing housing 3 and the oil drain 21 on the compressor side.
The oil is discharged from the oil discharge port 22 via

In the turbocharger, since the positive thrust acts on the thrust bearing 18 during normal operation,
The positive thrust side of the thrust bearing 18 is the load side, and the opposite thrust side is the non-load side, and the pad surface 1 on the positive thrust side
At the same time as the gap between the thrust bush 14 and the positive thrust bearing surface of the thrust bush 14 decreases, the gap between the pad surface 18b on the anti-thrust side of the thrust bearing 18 and the anti-thrust bearing surface of the oil drain 15 increases. A large amount of oil O flows to the anti-thrust side where the oil supply resistance is low.

[0006]

In the conventional turbocharger bearing structure, in order to increase the load capacity of the thrust bearing 18 with an increase in the supercharging pressure, the amount of lubricating oil required on the load side is increased. Therefore, there is a problem that a large amount of lubricating oil O must be supplied in consideration of the amount of lubricating oil flowing to the non-load side. Therefore, a bearing structure of a turbocharger incorporating a ball bearing capable of reducing the amount of lubricating oil O and reducing the resistance in rotation of the turbine shaft 6 to improve the response. Has been proposed.

In this ball bearing type bearing structure, for example, ball bearings for supporting the turbine shaft are incorporated into the through-hole of the turbine shaft of the bearing housing on the turbine side and the compressor side, respectively. Further, with these ball bearings alone, low vibration occurs in the through-hole of the turbine shaft of the bearing housing, and in order to suppress this vibration, the periphery of these ball bearings is held down by an oil film damper.

However, the conventional oil film damper is
Since it is made of a metal material such as stainless steel, the oil film damper does not move unless the turbine shaft rotates and vibrates to some extent due to its own weight. There was a problem that it was not demonstrated.

In addition, in this metal oil film damper, the weight of the metal oil film damper remains submerged in the turbine shaft penetrating portion, so that the rotation range in which the original damping function is exhibited after the rotation of the turbine shaft is limited. There was a problem that was.

The present invention has been made to solve such a problem. That is, an object of the present invention is to reduce the vibration generated when the turbine shaft of a turbocharger rotates by reducing the weight of an oil film damper supported from around the ball bearing of the turbine shaft in the turbine shaft penetration portion of the bearing housing. It is another object of the present invention to provide a turbocharger bearing structure capable of suppressing generation of noise.

[0011]

According to the present invention, there is provided a bearing structure for a turbocharger in which a turbine housing (1) and a compressor housing (2) are integrally connected via a bearing housing (3). (3) ball bearings (25, 26) fitted as journal bearings (3a) at both axial ends of the turbine shaft penetration portion;
An oil film damper (27) made of a heat-resistant synthetic resin material having a substantially cylindrical shape and inserted into the outer diameter of each ball bearing (25, 26) to absorb the vibration of (5, 26); The present invention provides a turbocharger bearing structure comprising:

The oil film damper (27) can be made of a thermosetting synthetic resin material. Alternatively, wood can be used instead of such a heat-resistant synthetic resin material.

According to the configuration of the present invention, the turbine shaft (6) is supported by the ball bearings (25, 26) incorporated respectively on the turbine side and the compressor side in the turbine shaft penetration portion. The amount of lubricating oil (O) supplied can be greatly reduced as compared with the structure. Further, by reducing the resistance in the rotation of the turbine shaft (6), the response of the bearing can be improved. These ball bearings (25, 2
6) is suppressed by the oil film damper (27), so that it is possible to suppress the low vibration generated in the turbine shaft penetrating portion.

In particular, in the present invention, the oil film damper (27) is made of a heat-resistant synthetic resin material and is lighter than a conventional metal film. It is easy to float and move. Therefore, the lightened oil film damper (27) has a ball bearing (25, 26).
Since the damping effect between the bearing and the bearing housing (3) can be enhanced, low vibration and low noise of the turbocharger can be realized.

Further, in order to maintain the axial position of the ball bearings (25, 26), an elastic member (31) can be interposed between the two ball bearings (25, 26).

The elastic member (31) prevents the ball bearings (25, 26) from moving in the direction of the turbine shaft (6), and suppresses the generation of vibration of the ball bearings (25, 26). Therefore, the ball bearings (25, 2) of the oil film damper (27) described above
Combined with the damping effect between 6) and the bearing housing (3), it is possible to further reduce the vibration and noise of the turbocharger.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings. In the drawings, common members are denoted by the same reference numerals, and redundant description is omitted. FIG.
1 is a side sectional view showing a bearing structure of a turbocharger of the present invention. FIG. 2 is an enlarged sectional view showing the oil film damper. The bearing structure of the turbocharger of the present invention is shown in FIG.
In the same manner as shown in FIG. 1, the turbine housing 1 and the compressor housing 2 are integrally connected via a bearing housing 3.
And a compressor wheel 5 in the compressor housing 2 connected by a turbine shaft 6 rotatably supported by a journal bearing (3a) in the bearing housing 3.

As shown in FIG. 2, the turbine shaft 6 has two ball bearings 25, which are fitted as journal bearings 3a in the turbine shaft through portion of the bearing housing 3 in order to lubricate the journal bearings 3a.
26. In order to absorb the vibrations of the ball bearings 25 and 26, the outer diameter portions of the ball bearings 25 and 26 are covered with an oil film damper 27 made of a substantially cylindrical heat-resistant synthetic resin material. Lubricating oil O supplied through an oil supply passage 28 provided in the bearing housing 3 is guided to the inner and outer peripheral surfaces of the oil film damper 27. This oil film damper 27 is fixed by a damper restraint 29 in the turbine shaft penetration portion.

Outside the turbine shaft 6 on which the compressor wheel 5 is mounted in the compressor housing 2, an oil drain 15 having an uneven surface is provided, and a compressor side sealing 1 is provided on the outer surface of the oil drain 15.
6, a seal plate 17 having an inner peripheral surface in contact with the compressor-side sealing 16 is attached to the bearing housing 3 to form an oil seal portion.

The oil film damper 27 of the present invention is made of a heat-resistant synthetic resin material, for example, a thermosetting synthetic resin material, and uses a lighter material than a conventional metal oil film damper. This is to make the oil film damper 27 easily float in the oil film of the lubricating oil O. Since the weight is reduced in this manner, the movement of the oil film damper 27 can be facilitated.

Further, the oil film damper 27
A groove 27a as shown in the figure is formed on the outer periphery so that an oil film of the lubricating oil O from the oil supply passage 28 is easily formed. By flowing the lubricating oil O into the groove 27a, an oil film of the lubricating oil O is easily formed on the outer periphery of the oil film damper 27. Since the oil film damper 27 is lightweight, the ball bearings 25, 2
The damping effect between the bearing housing 6 and the bearing housing 3 can be enhanced.

The oil film damper 27 of the present invention
The material is not limited to the above-mentioned synthetic resin material as long as it is easy to float and move in the oil film of the lubricating oil O and can form the groove 27a on the outer periphery thereof. Wood can be used as the material of the oil film damper 27 instead of this synthetic resin material. When the lubricating oil O is impregnated with the lubricating oil O, the heat resistance is improved, so that the lumber does not affect the damping effect and the durability does not decrease. Moreover, since the wood has a certain degree of flexibility, an oil film of the lubricating oil O is easily formed even when the groove 27a is not formed on the outer periphery unlike the oil film damper 27 made of a synthetic resin material, so that the damping effect can be enhanced. .

As shown in FIG. 2, the oil film damper 27 has a concave portion 27b for stopping rotation of the damper on the compressor side. 3
0 is fitted. Thereby, it is possible to prevent the oil film damper 27 from rotating carelessly and generating frictional heat.

An elastic member 31 such as a coil spring is interposed between the two ball bearings 25 and 26 in the turbine shaft penetrating portion. This elastic member 31 is for holding the position of the ball bearings 25 and 26 in the axial direction. Each of the ball bearings 25 and 26 has ring-shaped spring receivers 32 and 33 interposed therebetween so that the end of the elastic member 31 does not prevent the rotation of the ball.

The elastic member 31 prevents movement of the ball bearings 25 and 26 in the direction of the turbine shaft 6 and suppresses the generation of vibration of the ball bearings 25 and 26. Therefore, the elastic member 31 is provided with the ball bearings 25, 2 of the oil film damper 27 described above.
Along with the damping effect between the bearing 6 and the bearing housing 3, there is an effect of further reducing vibration and noise of the turbocharger.

In the turbocharger bearing structure thus configured, lubricating oil O is injected from an oil supply hole 34 in the upper part of the turbocharger, and the lubricating oil O passes through an oil supply passage 28 and an oil film damper 27 at the turbine shaft penetrating portion. Flows around. At this time, the lubricating oil O flows into the groove 27a formed on the outer periphery of the oil film damper 27, and forms an oil film of the lubricating oil O. In the oil film of the lubricating oil O, the oil film damper 27 made of a synthetic resin material or wood, which is lighter than a metal one, can easily float and move easily. Therefore, the oil film damper 27 that has become easy to float is provided with the ball bearing 2.
The damping effect between the bearing housings 3 and 5 and 26 is enhanced.

The lubricating oil O flowing through the oil film damper 27 passes through the oil film damper 27 and the turbine shaft 6 and is discharged to the lower portion of the turbocharger. Oil outlet 2 together with the lubricating oil O discharged by the rotation of the compressor side
2 can be drained.

In the oil film damper 27 of the present invention,
The lubricating oil O can be easily raised during rotation of the turbocharger so that it does not remain submerged in the turbine shaft penetration. Therefore, in the conventional metal oil film damper 27, it is possible to reduce the vibration that easily occurs when the turbocharger rotates.

The present invention is not limited to the above-described embodiment, but includes two ball bearings 25 and 26 in the turbine shaft through portion of the bearing housing 3 to support high-speed rotation of the turbine shaft. Although the embodiment in which the ball bearings are fitted is described, the number of these ball bearings 25 and 26 is not limited to two in the illustrated example, and it is possible to arrange three or more. Therefore, it goes without saying that various changes can be made without departing from the spirit of the present invention.

The material of the oil film damper 27 may be any material that floats in the oil film of the lubricating oil O, is light and easy to move, and has high heat resistance and high abrasion resistance. Lightweight sintered metal or the like can be used, and of course, various changes can be made without departing from the scope of the present invention.

[0031]

As described above, the bearing structure of the turbocharger according to the present invention supports the turbine shaft by the ball bearings respectively incorporated in the turbine side and the compressor side at the penetrating portion of the turbine shaft.
It is possible to reduce the lubricating oil supply amount and reduce the resistance in the rotation of the turbine shaft, thereby improving the response of the bearing. Since these ball bearings are held down by an oil film damper, it is possible to suppress the low vibration generated at the turbine shaft penetration.

In particular, in the present invention, since the oil film damper is made of a synthetic resin material or wood having a lighter heat resistance than conventional metal ones, it easily floats in the oil film of the lubricating oil. Because of the ease of movement, the lightened oil film damper can enhance the damping effect between the ball bearing and the bearing housing.

Further, since the elastic member of the present invention has the function of preventing the movement of both ball bearings in the axial direction of the turbine and suppressing the generation of vibration of these ball bearings, the above-described ball bearing of the oil film damper is provided. In addition to the damping effect between the turbocharger and the bearing housing, there is an excellent effect that the vibration and noise of the turbocharger can be more reliably reduced.

[Brief description of the drawings]

FIG. 1 is a side sectional view showing a bearing structure of a turbocharger of the present invention.

FIG. 2 is an enlarged sectional view showing an oil film damper.

FIG. 3 is a side sectional view showing a conventional thrust bearing structure of a turbocharger.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Turbine housing 2 Compressor housing 3 Bearing housing 3a Journal bearing 4 Turbine wheel 5 Compressor wheel 6 Turbine shaft 15 Oil drain 16 Compressor side sealing 17 Seal plate 20 Oil drain hole 21 Oil drain 22 Oil drain 25 Ball bearing (turbine side) 26 ball bearing (compressor side) 27 oil film damper 27a groove 27b damper anti-rotation recess 28 oil supply path 29 damper restraint 30 damper anti-rotation pin 31 elastic member 32, 33 spring receiver 34 oil supply hole O lubricating oil

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Claims (4)

[Claims] 1. A turbocharger bearing structure in which a turbine housing (1) and a compressor housing (2) are integrally connected via a bearing housing (3), wherein a shaft in a turbine shaft penetration portion of the bearing housing (3) is provided. Ball bearings (25, 26) fitted as journal bearings (3a) at both ends in the direction, and the outside of each ball bearing (25, 26) for absorbing vibration of the ball bearings (25, 26). A bearing structure for a turbocharger, comprising: an oil film damper (27) made of a heat-resistant synthetic resin material having a substantially cylindrical shape inserted into a diameter portion. 2. The oil film damper (27)
The turbocharger bearing structure according to claim 1, wherein the bearing structure is made of a thermosetting synthetic resin material. 3. A turbocharger bearing structure in which a turbine housing (1) and a compressor housing (2) are integrally connected via a bearing housing (3), wherein a shaft in a turbine shaft penetration portion of the bearing housing (3) is provided. Ball bearings (25, 26) fitted as journal bearings (3a) at both ends in the direction, and the outside of each ball bearing (25, 26) for absorbing vibration of the ball bearings (25, 26). A bearing structure for a turbocharger, comprising: an oil film damper (27) made of wood having a substantially cylindrical shape inserted into a diameter portion. 4. An elastic member (31) is interposed between two ball bearings (25, 26) to maintain an axial position of the ball bearings (25, 26). 4. The turbocharger bearing structure according to claim 1, 2 or 3.