JP2010096119A - Bearing device for turbocharger - Google Patents

Abstract

Provided is a bearing device for a turbocharger capable of ensuring lubrication of a piston ring type seal and suppressing oil leakage to a compressor side.
A pair of rolling bearings 4 and 5 that rotatably support a rotating shaft having a turbine side impeller and a compressor side impeller at both ends, the rolling bearings 4 and 5 are held, and engine oil is held in these bearings. A turbocharger including a housing 11 having a first oil supply path P1 that guides the gas and a piston ring-type seal 12 that seals a radial clearance between the vicinity of the turbine-side end 10g of the housing 11 and the rotary shaft 1. In the bearing apparatus for use, a second oil supply path P <b> 2 that diverts from the first oil supply path P <b> 1 and guides engine oil to the seal 12 is formed in the housing 11.
[Selection] Figure 1

Description

  The present invention relates to a bearing device that supports a rotating shaft of a turbocharger (supercharger) mounted on a vehicle such as an automobile.

A turbocharger is a device that rotates a turbine by exhaust gas from an engine, drives a compressor by the rotation, and compresses air for intake to the engine. The rotating shaft of such a turbocharger is rotatably supported by a rolling bearing. However, since the rotational speed is very large (for example, 200,000 times per minute), oil lubrication of the rolling bearing is necessary. In view of this, there has been proposed a bearing device in which an oil supply path is provided in a housing that holds a rolling bearing, and engine oil is supplied to the rolling bearing (see, for example, Patent Documents 1 and 2).
On the other hand, a piston ring type seal is provided to seal the radial gap between the vicinity of the turbine side end of the housing and the rotating shaft so that the exhaust gas does not enter the housing. This seal is lubricated by the engine oil adhering to the rotating shaft being scattered by centrifugal force.

JP 2002-54449 A JP 2002-54451 A

However, it is somewhat inferior to rely on the lubrication of the seals for oil supply by splashing. Therefore, sticking of the seal may occur. On the other hand, there is a case where the oil supply is excessive for the rolling bearing. In this case, the engine oil leaks to the compressor side and is mixed with intake air.
SUMMARY OF THE INVENTION In view of such conventional problems, an object of the present invention is to provide a turbocharger bearing device capable of ensuring the lubrication of a piston ring type seal and suppressing oil leakage to the compressor side. And

  A turbocharger bearing device according to the present invention includes a pair of rolling bearings rotatably supporting a rotating shaft having a turbine-side impeller and a compressor-side impeller at both ends, and holds the rolling bearing, and engine oil is supplied to them. A housing having a first oil supply passage for guiding, and a piston ring type seal that seals a radial clearance between the vicinity of the turbine side end of the housing and the rotating shaft, and the housing includes the first oil A second oil supply path is formed which diverts from the supply path and guides engine oil to the seal.

  In the turbocharger bearing device configured as described above, the second oil supply passage is provided, so that the engine oil branched from the first oil supply passage is reliably guided to the seal. Further, by providing the second oil supply path, the flow rate of engine oil guided from the first oil supply path to the rolling bearing is reduced.

  According to the turbocharger bearing device of the present invention, by providing the second oil supply path, the piston ring type seal can be reliably lubricated and oil leakage to the compressor side can be suppressed. be able to.

  FIG. 1 is a cross-sectional view of a turbocharger bearing device according to an embodiment of the present invention. In the figure, a turbine side impeller 2 and a compressor side impeller 3 are attached to both ends of the rotary shaft 1, respectively. The turbine side impeller 2 is rotated by exhaust gas from the engine, and the compressor side impeller 3 compresses the air for intake to the engine by the rotation. The rotating shaft 1 is rotatably attached to a substantially cylindrical inner housing 6 by a pair of rolling bearings (angular ball bearings) 4 and 5. Preloads due to the elastic force of the compression springs 7 are applied to the outer rings of the rolling bearings 4 and 5 in the axial direction via the sleeves 8 and 9, respectively.

  The inner housing 6 is held by an outer housing 10, and both form a housing 11 that holds the rolling bearings 4 and 5. The outer housing 10 is formed with an oil supply path (details will be described later) for guiding engine oil as lubricating oil, a discharge outlet 1b for discharging, and a jacket 10a for passing cooling water.

  Further, in order to seal a radial gap between the vicinity of the turbine side end 10 g of the outer housing 10 and the rotating shaft 1, a piston ring type seal 12 is provided in a circumferential groove 1 a formed on the outer periphery of the rotating shaft 1. It is installed. The seal 12 has, for example, a shape in which one portion of the ring is cut, and the outer diameter in a free state is slightly larger than the inner diameter of the turbine side end portion 10 g of the outer housing 10. Further, the inner diameter of the seal 12 in a state of being mounted as shown in FIG.

FIG. 2 is an enlarged cross-sectional view of a part of FIG. FIG. 3 is a cross-sectional view further enlarging the III part of FIG. In each figure, the arrow indicates the direction in which engine oil flows.
In FIG. 2, the outer housing 10 is formed with a first oil supply path P <b> 1 that guides engine oil to the rolling bearings 4 and 5. The first oil supply path P1 communicates with the introduction hole 10b formed in the radial direction, the lower end of the introduction hole 10b, the lateral hole 10c extending in the axial direction, the communication with the lateral hole 10c, and in the radial direction. The vertical hole 10d is formed.

  Further, the outer housing 10 is formed with a second oil supply path P2 that diverts from the first oil supply path P1 and guides engine oil to the seal 12. The second oil supply path P2 communicates with a narrow horizontal hole 10e communicating with the axially left end (turbine side) end of the horizontal hole 10c of the first oil supply path P1, and with an end of the horizontal hole 10e. It is constituted by a radial vertical hole 10f reaching the vicinity.

  By providing the second oil supply path P2 as described above, the engine oil is reliably guided to the seal 12. In FIG. 3, the seal 12 has the inner and outer diameter dimensions as described above, so that it sticks to the inner peripheral surface of the turbine side end 10g of the outer housing 10, and between the bottom surface and the wall surface of the peripheral groove 1a. Has a space to draw engine oil. Therefore, the engine oil enters as shown by the arrow, and oil lubrication is realized between the stationary seal 12 and the rotating shaft 1 rotating at high speed. Thereby, lubrication of the piston ring type seal 12 can be ensured.

  Further, by providing the second oil supply path P2 as described above, the flow rate of the engine oil guided from the first oil supply path P1 to the rolling bearings 4 and 5 decreases. Therefore, oil leakage to the compressor side can be suppressed.

It is sectional drawing of the bearing apparatus for turbochargers which concerns on one Embodiment of this invention. It is sectional drawing to which a part of FIG. 1 was expanded. It is sectional drawing which expanded further the III section of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Rotating shaft 2 Turbine side impeller 3 Compressor side impeller 4,5 Rolling bearing 6 Inner housing 10 Outer housing 11 Housing 12 Seal P1 First oil supply path P2 Second oil supply path

Claims (1)

A pair of rolling bearings rotatably supporting a rotating shaft having a turbine side impeller and a compressor side impeller at both ends;
A housing having a first oil supply path for holding the rolling bearing and guiding engine oil to the rolling bearing;
A piston ring type seal that seals a radial gap between the vicinity of the turbine side end of the housing and the rotating shaft;
2. A turbocharger bearing device according to claim 1, wherein a second oil supply path is formed in the housing for diverting from the first oil supply path to guide engine oil to the seal.

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