JPH0426662Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an oil leakage prevention device provided to prevent lubricating oil for a bearing in a turbocharger housing from leaking to the compressor wheel side. be.

[Conventional technology]

A large amount of lubricating oil flows into the bearing in the center housing of the turbocharger and is used for lubrication and cooling the housing.This oil is transferred from the shaft on the compressor side to the compressor by negative pressure on the back of the compressor wheel. If inhaled into the side, various problems may occur, so
It is necessary to prevent this oil from leaking to the compressor side.

Conventionally, a mechanical seal type or a piston ring type seal has been used as a means for preventing this lubricating oil from leaking, and techniques showing improvements to the mechanical seal type are disclosed in, for example, Japanese Utility Model Application Publication No. 56-129532,
It is disclosed in Japanese Utility Model Application No. 59-137331.

The mechanical seal type oil leakage prevention device described above prevents oil from leaking to the compressor side by placing a carbon seal pressed by a spring in close contact with a thrust collar that is fitted onto the shaft and rotates with it. . Since this carbon seal is in close contact with the thrust collar, which rotates at high speed, it is easy for seizure to occur in this contact area, so an oil film is formed on this part to prevent seizure.

[Problem that the invention attempts to solve]

The mechanical seal system has the advantage of superior sealing performance compared to piston ring seals, but because of its poor transient characteristics, in the past, attempts were made to obtain transient characteristics comparable to those of piston ring seals by weakening the force of the spring pressing the carbon seal or by reducing the contact area between the carbon seal and the thrust collar. Therefore, when the pressure on the compressor side falls below atmospheric pressure or when the internal pressure of the turbocharger rises, the lubricating oil in the turbocharger can overcome the pressing force of the spring and leak from the contact surface between the carbon seal and the thrust collar to the compressor side.

In view of the above points, the present invention aims to provide an oil leakage prevention device that maintains the good sealing properties of the mechanical seal type and also provides transient characteristics comparable to those of the piston ring type seal.

[Means for solving problems]

According to the present invention, the above problem can be solved by using an annular seal that is fitted and supported within the center housing and that is penetrated by the fixed shaft of the compressor wheel so that the wheel is positioned outside the center housing. a retainer, a thrust collar supported by a thrust bearing fixed to the center housing and fitted onto the shaft and rotated therewith; a thrust collar supported by the seal retainer and whose tip is connected to a side surface of the compressor side of the thrust collar; In the oil leakage prevention device for a turbocharger, the turbocharger oil leakage prevention device includes a carbon seal that is biased to come into contact with a carbon seal, and an annular ring concentric with the shaft into which the tip of the carbon seal fits into the side surface of the thrust collar on the carbon seal contact side. By providing an oil leak prevention device for a turbocharger, comprising a groove, and a radial groove communicating with the annular groove and extending from the groove toward the outer periphery of the thrust collar. , will be resolved.

〔Example〕

Embodiments of the present invention will be described with reference to the drawings.

FIG. 4 shows the overall configuration of a turbocharger to which an embodiment of the present invention is applied. In the figure, a bearing portion 3 for pivotally supporting a shaft 2 is formed within a center housing 1, and a compressor housing 4 and a turbine housing 5 are provided on both sides of the center housing 1. The shaft 2 is provided with a compressor wheel 6 at one end and a turbine wheel 7 at the other end, and the compressor wheel 6 is housed in the compressor housing 4 and the turbine wheel 7 is housed in the turbine housing 5, respectively. A floating radial bearing 8 provided between the shaft 2 and the bearing part 3 has an oil hole 9 formed in the radial direction, and is rotatable relative to the shaft 2 and the bearing part 3. The lubricating oil is supplied around the radial bearing 8 through a supply hole (not shown), flows around the shaft 2 through the oil hole 9, is discharged to the outside through the oil drain passage 10, and some of the lubricating oil is supplied to the thrust collar 14 side, which will be described later.

An annular seal retainer 11 is fitted on the compressor wheel 6 side of the center housing 1, and an inverted U-shaped thrust bearing 12 is attached inside the seal retainer 11. The shaft 2 includes these seal retainers 11 and thrust bearings 1.
2, a cylindrical seal ring collar 13 is provided between the shaft 2 and the seal retainer 11, and a cylindrical thrust collar 14 having flanges at both ends is provided between the shaft 2 and the thrust bearing 12. Each is provided. The seal ring collar 13 and the thrust collar 14 are integrally fixed to the shaft 2.

FIG. 1 shows the main parts of this embodiment, in which the thrust collar 14 of the seal retainer 11 is shown.
A carbon seal 15 is housed in a recess formed on the side surface facing the carbon seal 1.
5 has a rear end connected to a spring 17 via a spring receiver 16.
The tip 1 of the thrust collar 14 is pushed toward the side of the thrust collar 14.
5a is in contact with the side surface of the thrust collar 14. On the other hand, on the thrust collar 14 side, as shown in FIG. 2, an annular groove 18 concentric with the shaft 2 is provided in the part where the carbon seal 15 contacts.
The tip 15a of the carbon seal fits into this annular groove 18. Thrust color 14
Furthermore, several grooves 19 are provided which communicate with the annular groove 28 and extend radially from the annular groove 18 toward the outer periphery of the thrust collar 14 .

Note that the above-mentioned radial grooves 19 may be linear grooves as shown in FIG. 3 instead of being curved grooves as shown in FIG. 2.

In this embodiment configured as described above, when the shaft 2 to which the turbine wheel 7 and compressor wheel 6 are fixed rotates, the seal ring collar 13 and thrust collar 14 fixed to this shaft 2 also rotate. . On the other hand, the carbon seal 15 supported within the seal retainer 11
is pressed against the thrust collar 14 side by the spring 17, and its tip 15a is pressed against the thrust collar 1.
4 into the annular groove 18, and these tip portions 15a
A labyrinth is formed in which the clearance between the groove 18 and the groove 18 is maintained at a minimum gap that allows only oil particles to be present. By keeping the clearance to a minimum, the viscosity of the oil between the tip 15a and the annular groove 18 increases, and in addition, the viscosity of the oil increases further due to the pressing force of the spring, which prevents labyrinth during shaft rotation. The sealing effect is significantly improved and the leakage of lubricating oil to the compressor side is thus prevented. The oil that has entered the annular groove 18 is removed by the radial concave grooves 1 toward the outer periphery.
9 and reaches the oil drain passage 10 via the vicinity of the thrust collar 14.

Further, since the tip 15a is urged toward the annular groove 18 by the spring 17, even if the shaft 2 is displaced in the axial direction, the tip 15a is pressed against the annular groove 18, and the gap between the tip 15a and the annular groove 18 is reduced. It is always kept at a minimum, and the sealing effect of the labyrinth can always be maximized.

As a result, oil is less likely to enter the contact area between the carbon seal 15 and the thrust collar 14, and oil leakage to the compressor side can be prevented.

FIG. 5 shows a second embodiment of the present invention.

In this embodiment, a groove 1 is formed on the tip surface of the carbon seal 15.
5b, and insert the tip pieces 15 on both sides of this groove 15b.
c, 15c is the annular groove 18 on the thrust collar 14 side
(See Figures 2 and 3).

In this way, a groove 1 is formed on the tip surface of the carbon seal 15.
By providing 5b, the surface pressure of the tip surface of the carbon seal 15 against the annular groove 18 becomes large, thereby further improving the oil sealing effect.

[Effect of idea]

As described above, in the present invention, an annular groove is provided on the abutment surface of the carbon seal and the thrust collar, and concave grooves are further provided radially from this annular groove, so the labyrinth effect between the carbon seal and the annular groove creates a compressor. Oil leakage to the sides is effectively prevented, and the oil in the annular groove is sent out to the outside of the thrust collar through the radial grooves due to the centrifugal force of the thrust collar, making the leakage prevention effect even better. becomes.

Furthermore, by improving the sealing performance as described above, the force of the spring that presses the carbon seal can be weakened, and the contact area between the carbon seal and the thrust collar can also be reduced, thus achieving the same transient performance as a piston ring type seal. It becomes something that can be obtained.

[Brief explanation of drawings]

Fig. 1 is a longitudinal cross-sectional view of the main part of the embodiment of the present invention, Fig. 2 is a front view of the thrust collar in the above embodiment, Fig. 3 is a front view showing a modification of the above thrust collar, and Fig. 4 is a front view of the thrust collar in the above embodiment. FIG. 5 is an enlarged sectional view showing a main part of another embodiment of the present invention. 1... Center housing, 2... Shaft,
6... Compressor wheel, 11... Seal retainer, 12... Thrust bearing, 14...
Thrust color, 15...Carbon seal, 15
b... Groove, 15c... Tip piece, 18... Annular groove,
19...Radial concave groove.

Claims (1)

[Scope of utility model registration request] an annular seal retainer that is fitted and supported within the center housing and through which the shaft to which the compressor wheel is fixed is positioned so that the wheel is located outside the center housing; and a thrust bearing that is fixed to the center housing. a carbon seal supported by the seal retainer and urged such that its tip abuts against a side surface of the thrust collar on the compressor side; In the oil leakage prevention device for a turbocharger, an annular groove is provided on the side surface of the thrust collar on the carbon seal contacting side, which is concentric with the shaft into which the tip of the carbon seal is fitted, and further communicates with the annular groove. An oil leak prevention device for a turbocharger, characterized in that a radial groove is provided extending from the groove toward the outer periphery of the thrust collar.