JP6637227B2 - Turbocharger oil leakage control structure - Google Patents

Description

  The present invention relates to a turbocharger oil leakage suppressing structure.

  FIG. 3 shows a peripheral structure of a turbine wheel 1 in a general turbocharger. A rotating shaft 2 of the turbine wheel 1 is rotated by a boss 4 in a bearing housing 3 via a radial bearing 5 (floating metal). The turbine wheel 1 is movably supported, and is driven to rotate by exhaust gas 6 introduced from the tangential direction.

  Lubricating oil 8 is supplied to the radial bearing 5 via an oil path 7 in the bearing housing 3. Lubricating oil 8 discharged from a gap between the radial bearing 5 and the rotating shaft 2 is Before leaking toward the turbine wheel 1 or the compressor wheel (not shown), the centrifugal force of the rotating shaft 2 causes the oil to be blown off by the oil discharge port 9 and returned to the oil pan.

  However, if the amount of lubrication increases significantly when the turbo rotation speed is low and the centrifugal force is weak, the oil drainage to the oil discharge port 9 becomes insufficient, and the oil is discharged to the turbine wheel 1 or a compressor wheel (not shown). Since the oil leakage may occur, the rotary shaft 2 outside the radial bearing 5 is provided with an oil seal 10 for blocking the lubricating oil 8 leaking from the radial bearing 5.

  The oil seal 10 engages with a groove 11 formed on the rotating shaft 2 side to be fitted therein. However, the oil seal 10 itself is fixed by a resilient force to expand its diameter. It is adapted to be fitted inside the hole 12 on the housing 3 side and fixed.

  On the other hand, between the oil seal 10 and the radial bearing 5, an oil cut chamber 13 having a space around the rotary shaft 2 is provided, and the rotary shaft 2 in the oil cut chamber 13 has The lubricating oil 8 reaching the slinger 14 flows to the outer peripheral side by centrifugal force and scatters on the wall surface of the oil cut chamber 13. That is, the situation where the lubricating oil 8 flows over the slinger 14 against the centrifugal force and flows again toward the inner peripheral side does not occur, so that the oil is surely cut off here.

  As prior art document information related to this type of turbocharger oil leakage suppressing structure, there is the following Patent Document 1 and the like.

JP 2001-289052 A

  However, as shown in the enlarged view of FIG. 4, when the lubricating oil 8 collectively leaks from the radial bearing 5, the lubricating oil 8 comes into contact with the slinger 14 so that the end face 4 a of the boss portion 4 is tensioned by surface tension. The lubricating oil 8 scattered upward while co-rotating and scattered upward reaches the oil seal 10 along the wall surface of the oil cut chamber 13 and passes through the notch of the oil seal 10 to generate a turbine blade due to a pressure difference. There is a possibility that white smoke may be generated by being sucked out to the vehicle 1 side.

  That is, a resin lip seal that can completely seal the lubricating oil 8 cannot be used for the oil seal 10 of the rotating shaft 2 of the turbine wheel 1 that rotates at high speed. An oil seal 10 composed of a ring is used, and it is difficult for such an oil seal 10 to completely seal the lubricating oil 8.

  Since this type of turbocharger is designed to be as compact as possible from the viewpoint of improving the mountability on a vehicle, the gap between the end face 4a of the boss portion 4 and the slinger 14 is more than necessary. There is a situation that a large space cannot be secured.

  SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide a turbocharger oil leakage suppressing structure capable of significantly suppressing a situation in which lubricating oil from a radial bearing leaks to a turbine wheel.

According to the present invention, a rotating shaft of a turbine wheel is rotatably supported by a boss in a bearing housing via a radial bearing, and lubricating oil is supplied to the radial bearing via an oil path in the bearing housing. With such a configuration, an oil seal for blocking lubricating oil leaking from the radial bearing is provided on a rotating shaft outside the radial bearing,
An oil leakage suppression structure for a turbocharger, wherein an oil cut chamber having a space around a rotation shaft is provided between the oil seal and the radial bearing, and a flange-shaped slinger is provided on a rotation shaft in the oil cut chamber,
An end surface of the boss portion facing the slinger in the axial direction of the rotation shaft is tapered so as to be separated from the slinger side toward an outer peripheral side of the end surface,
Even when the lubricating oil leaked from the radial bearing comes into contact with the slinger and starts to rotate together with the lubricating oil sticking to the end surface of the boss portion by the surface tension, the lubricating oil may be applied to the end surface of the boss portion. It is characterized in that it is configured so that it is harder to co-rotate away from the slinger side toward the outer peripheral side.

In this case, when the lubricating oil that has leaked from the radial bearing collectively comes into contact with the slinger, the lubricating oil starts rotating together with the lubricating oil stuck to the end face of the boss portion by surface tension. As it moves toward the outer peripheral side of the end face of the boss portion, it becomes difficult to cause co-rotation as it separates from the slinger side, so that the lubricating oil does not lift upward on the way to the outer peripheral side of the end face of the boss portion and flows down by gravity. Even if part of the lubricating oil splatters upwards, the lubricating oil will splatter in the direction away from the slinger side. The situation of reaching the oil seal is avoided.

In the present invention, the end face of the boss may have a linear taper shape, or the end face of the boss may have a parabolic taper shape. The co-rotation gradually becomes difficult to occur at a constant rate toward the outer peripheral side of the end face, but in the case of a parabolic taper shape, a tendency is set such that the co-rotation hardly occurs near the outer circumference of the end face of the boss portion. You.

  According to the above-described oil leakage suppressing structure of the turbocharger of the present invention, even if the lubricating oil that has leaked from the radial bearing has come into contact with the slinger and co-rotates while being stuck to the end surface of the boss portion by surface tension, The tapered shape on the end face of the boss can significantly suppress the lubricating oil from splashing upwards, and even if some of the lubricating oil splashes upwards, it does so in the direction away from the slinger side. Therefore, it is possible to prevent a situation in which the lubricating oil reaches the oil seal by contacting the wall surface of the oil cut chamber, and the lubricating oil leaks to the turbine wheel due to a pressure difference through the notch of the oil seal. Various excellent effects can be achieved, such as the occurrence of white smoke can be prevented by suppressing the occurrence of white smoke.

It is a sectional view showing an example of an embodiment of the present invention. It is sectional drawing which shows another form example of this invention. It is sectional drawing which shows the peripheral structure of the turbine wheel of a general turbocharger. FIG. 4 is an enlarged sectional view showing a main part of FIG. 3.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 shows an example of an embodiment of the present invention, and the portions denoted by the same reference numerals as those in FIGS. 3 and 4 represent the same components.

  As shown in FIG. 1, the present embodiment is directed to a turbocharger having substantially the same configuration as that of FIG. 4 described above, and a rotating shaft 2 of a turbine wheel 1 is radially formed by a boss 4 in a bearing housing 3. An oil seal 10 is provided on the rotating shaft 2 outside the radial bearing 5 so as to be rotatable via a bearing 5, and a space around the rotating shaft 2 is provided between the oil seal 10 and the radial bearing 5. An oil cutting chamber 13 is provided, and a flange-shaped slinger 14 is provided on the rotating shaft 2 in the oil cutting chamber 13, but faces the slinger 14 in the axial direction of the rotating shaft 2. The end face 4a of the boss portion 4 is tapered so as to be separated from the slinger 14 side toward the outer peripheral side of the end face 4a, In the example being illustrated in this exemplifies the case denoted by the tapered shape as a linear taper.

In this case, when the lubricating oil 8 leaked from the radial bearing 5 collectively comes into contact with the slinger 14, the lubricating oil 8 rotates together with the end face 4a of the boss portion 4 while being stuck to the surface 4a by surface tension. However, as the lubricating oil 8 moves away from the slinger 14 as the lubricating oil 8 moves toward the outer peripheral side of the end surface 4a of the boss portion 4, it becomes difficult for co-rotation to occur. As a result, the lubricating oil 8 is not lifted upward and flows down due to gravity. Even if a part of the lubricating oil 8 scatters upward, the lubricating oil 8 scatters in a direction away from the slinger 14 side. Therefore, a situation in which the lubricating oil 8 reaches the oil seal 10 along the wall surface of the oil cut chamber 13 is avoided.

  Therefore, according to the above embodiment, even if the lubricating oil 8 leaked from the radial bearing 5 collectively comes into contact with the slinger 14 and rotates together with the end face 4a of the boss 4 by the surface tension, the boss 4 Due to the tapered shape of the end face 4a of the lubricating oil 4, the lubricating oil 8 can be prevented from spattering upward, and even if a part of the lubricating oil 8 spatters upward, the lubricating oil 8 is separated from the slinger 14 side. The lubricating oil 8 can be prevented from reaching the oil seal 10 along the wall surface of the oil cut chamber 13, and can be lubricated by a pressure difference through the notch of the oil seal 10. The situation in which the oil 8 leaks to the turbine wheel 1 can be significantly suppressed, and the generation of white smoke can be prevented.

Further, in the embodiment described above, the example in which the end face 4a of the boss portion 4 has a linear tapered shape is described. However, as shown in FIG. The end face 4a may have a parabolic taper shape. In the case of a linear taper shape, it is difficult for the end face 4a to gradually rotate together with the end face 4a of the boss portion 4 toward the outer peripheral side of the end face 4a. for would so that trend suddenly rotate together around the periphery is unlikely to occur in the end surface 4a of the boss portion 4 is set.

  The oil leakage suppressing structure of the turbocharger of the present invention is not limited to the above-described embodiment, and it is needless to say that various changes can be made without departing from the gist of the present invention.

DESCRIPTION OF SYMBOLS 1 Turbine wheel 2 Rotating shaft 3 Bearing housing 4 Boss part 4a End face 5 Radial bearing 8 Lubricating oil 10 Oil seal 13 Oil cutting chamber 14 Slinger

Claims (3)

The rotating shaft of the turbine wheel is rotatably supported by a boss in a bearing housing via a radial bearing, and lubricating oil is supplied to the radial bearing via an oil path in the bearing housing. An oil seal for blocking lubricating oil leaking from the radial bearing is provided on a rotating shaft outside the radial bearing,
An oil leakage suppression structure for a turbocharger, wherein an oil cut chamber having a space around a rotation shaft is provided between the oil seal and the radial bearing, and a flange-shaped slinger is provided on a rotation shaft in the oil cut chamber,
An end surface of the boss portion facing the slinger in the axial direction of the rotation shaft is tapered so as to be separated from the slinger side toward an outer peripheral side of the end surface,
Even when the lubricating oil leaked from the radial bearing comes into contact with the slinger and starts to rotate together with the lubricating oil sticking to the end surface of the boss portion by the surface tension, the lubricating oil may be applied to the end surface of the boss portion. An oil leakage suppressing structure for a turbocharger, characterized in that it is configured to be separated from a slinger side as it moves toward an outer peripheral side so that co-rotation hardly occurs .   The turbocharger oil leakage suppressing structure according to claim 1, wherein a linear tapered shape is provided on an end surface of the boss portion.   The structure for suppressing oil leakage of a turbocharger according to claim 1, wherein a parabolic taper shape is provided on an end surface of the boss portion.

Images