JPS6044497B2 - Turbo charger compressor side shaft sealing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a turbocharger, and particularly to an improvement of a compressor side shaft sealing device.

Some conventional turbochargers have a carburetor for gasoline engines installed upstream of the compressor.
In this case, oil is likely to leak from the shaft of the compressor due to the large negative pressure generated downstream of the throttle valve of the carburetor. In order to prevent this oil leakage, a complete contact type carbon seal ring is used. However, this type of contact seal has problems such as large mechanical friction loss at the contact area, which significantly reduces the performance of the turbocharger, and the sealing material wears out and loses its sealing properties during long-term operation. . Also, when using a turbocharger in combination with a diesel engine or a gasoline engine with an electronic fuel injection valve,
The influence of the throttle part as mentioned above is small, and at most the friction loss of the compressor wheel causes about -1007
Since only a negative pressure of about TUnHg is generated, a non-contact type shaft sealing device using a piston ring is generally used.

FIG. 1 is a sectional view showing a conventional compressor side shaft sealing device as seen in Japanese Patent Application Laid-Open No. 54-147315. The turbine shaft 1 is held by a radial bearing 3 provided inside a center housing 2, and its narrow diameter portion on the right side passes through a thrust collar 6 and enters a compressor wheel chamber 5, where a compressor wheel 4 is attached. ing.
Since the thrust collar 6 is fastened together with the turbine shaft 1, the turbine shaft 1, the thrust collar 6, and the compressor wheel 4 rotate together. The thrust collar is connected to the back plate 7 via the piston ring 10.
A thrust groove 11 is formed between a large diameter disk 17 formed in the middle part of the thrust collar 6 and the large diameter part at the left end, into which the thrust bearing 8 is fitted. That is, the thrust bearing 8 and the thrust collar 6 suppress the horizontal movement of the turbine shaft 1. A seal plate 16 is attached to the thrust collar 6 by inserting a hole 20 into the seal plate 16. The upper part of the seal plate 16 forms a flange 19 and comes into contact with the right side of the thrust bearing 8. A partition plate 21 is formed. Further, this seal plate 16 is brought into close contact with the thrust bearing 8 by a plate-shaped thrust spring plate 22 to form an oil chamber 18, and has the function of introducing oil that has lubricated the thrust bearing 8 into the drain boat 13. There is. Also, oil chamber 1
8 The lubricating oil that overflowed outside is also drained from the drain port 12 to the drain boat 1.
It is discharged at 3. Note that the thrust spring plate 22 presses the thrust bearing 8 against the center housing 2 to counter the thrust load and prevents the thrust bearing 8 from moving. Second
The figure is a sectional view taken along the line AA in FIG. 1, and FIG. 3 is a sectional view taken along the line BB in FIG.

The thrust bearing 8 is positioned in the center housing 2 by a pair of knock pins 14, and a notch 15 is provided below the knock pin 14 for inserting the thrust collar 6 therein. As described above, the seal plate 16 surrounds the disk 17 of the thrust collar 6 to form an oil chamber 18, and has a partition plate 21 protruding from the notch 15. As shown in FIG. 3, the knock pin 14 and the seal plate 16 are engaged with the center housing 2 together with the thrust bearing 8, thereby fixing the position of the seal plate 16.

In the conventional compressor shaft sealing device configured as described above, the oil that lubricates the thrust bearing 8 comes into contact with the rotating shaft of the thrust collar 6, receives centrifugal force, and is discharged radially.

In particular, at a high speed of 150,000 revolutions per minute, the turbine shaft 1
When it is rotating, it reaches a very high speed of 150 to 200 m/s. In addition, as shown in FIG. 2, a gap b is necessarily created between the notch 15 of the thrust bearing 8 and the partition plate 21 during assembly, and the hole 20 provided in the seal plate 16 is Oil with energy first enters the chamber on the right side of the seal plate 16, and when the compressor blade chamber 5 is depressurized, some of the oil passes through the piston ring 10 and leaks into the compressor blade chamber 5. This caused the problem of doing so. In particular, the size of the oil chamber 18 that surrounds the disk 17 of the thrust collar 6 is limited by the pair of dowel pins 14 installed to determine the position of the seal plate 16.
In this state, the oil chamber 18 is filled with oil and the seal plate 16
A large amount of oil overflows from between the flange 19 and the thrust bearing 8, resulting in an increase in the amount of oil entering the compressor blade chamber 5. An object of the present invention is to provide a compressor-side shaft sealing device for a turbocharger that has a simple structure and does not cause oil leakage even during high-speed operation. The present invention is constructed using a seal plate that surrounds the end surface of the bearing on the compressor side and has a bent portion that contacts the outer circumferential surface of the thrust bearing. FIG. 4 is a sectional view of essential parts of a compressor-side shaft sealing device according to an embodiment of the present invention, in which the same parts as in FIG. 1 are given the same reference numerals.

In this case, the seal plate 16 is brought into close contact with the surface of the thrust bearing 8 facing the back plate 7, and the bent part 23 is formed in its extension to bring it into close contact with the outer peripheral surface of the thrust bearing 8. The tip of the bent portion 23 is tightly fitted into a guide groove 24 formed on the surface of the center housing 2 except for a portion thereof. Further, at the lower end of the seal plate 16, a partition plate 21 protruding from the notch 15 of the thrust bearing 8 extends into the drain boat 13 so as to surround the notch 15 more than in the case of FIG.
Therefore, the oil in the oil chamber 18 is guided by the partition plate 21 and easily flows out to the drain boat 13, and the oil leaking into the compressor blade chamber 5 through the gap 9 where the piston ring 10 is present is significantly reduced. decreases to Figure 5 is C of Figure 4.
-C'' sectional view, a pair of knock pins 14a and 14b are driven into the center housing as shown in Figure 3 to position the seal plate 16 and prevent it from rotating.The compressor side shaft of this embodiment The sealing device is formed so that the seal plate 16 covers the disk 17 and the thrust bearing 8 and is fitted into the guide groove 24 provided on the surface of the center housing 2. can be well guided.
Therefore, the effect that oil leaking into the compressor blade chamber 5 through the gap between the turbine shaft 1 and the back plate 7 can be significantly reduced is obtained. FIG. 6 is a sectional view of a main part of a compressor-side shaft sealing device according to another embodiment of the present invention, in which the same parts as in FIG. 4 are given the same reference numerals.

The length of the bent portion 23 of the seal plate 16 is less than the thickness of the thrust bearing 8, and the center housing 2 is not provided with a guide groove. Further, a bent portion is also provided at the notch portion 15, and instead of the bent portion, the partition plate 21 shown by the broken line is not provided at this time. FIG. 7 is a sectional view taken along the line DD'' in FIG. 6, and shows that the partition plate 21 is omitted.

Further, in this case, since the seal plate 16 is annular and symmetrical with respect to the turbine shaft 1, there is no problem even if the seal plate 16 rotates as long as the bent portion 23 does not separate from the side surface of the thrust bearing 8. Therefore, in this case, there is no need to drive in a dowel pin to fix the seal plate 16. Note that, as shown in FIG. 6, the back plate 7 is brought close to the disk 17 to prevent the seal plate 16 from separating from the thrust bearing 8. In this way, the thrust spring plate 22 is also unnecessary, and the thrust bearing portion can be made smaller and simpler. The compressor-side shaft sealing device of this embodiment uses a cap-shaped seal plate 16 that covers up to the outer peripheral surface of the disk 17 and the thrust bearing 8, thereby omitting the knock pin 14, the partition plate 21, and the thrust spring plate 22. This provides the effect that the bearing portion can be made smaller and simpler.

8 and 9 are sectional views corresponding to FIG. 7 of a compressor-side shaft sealing device that is a modification of FIG. 6. In FIG. 8, a bent portion 23a is provided on the upper part of the seal plate 16 around the thrust bearing 8, and a notch 1 of the thrust bearing 8 is provided.
A bent portion 23b is provided so as to surround 5.
Even in this case, the oil that has lubricated the thrust bearing 8 can be discharged to the drain boat 11 as well as in the case shown in FIG. 7, but in this case, it is necessary to prevent the seal plate 16 from rotating. Dowel pin 14a, 1
4b to the thrust bearing 8. In the case of FIG. 9, a bent portion 23 is attached with a partition plate 21 so as to cover only the notch 15 of the thrust bearing 8.
It has been established.

In this case, since the position of the seal plate 16 must be fixed, a pair of knock pins 14a and 14b are used. The seal plates 16 shown in FIGS. 8 and 9 have the function of guiding the oil that lubricates the thrust bearing 8 to the drain boat 13, and also function as a simple and inexpensive shaft sealing device on the compressor side. .

In all of the above embodiments of the present invention, the lubricating oil released from the vicinity of the thrust bearing 8 by centrifugal force is transferred to the seal plate 1.
The bent portion 23 of No. 6 effectively collects and discharges the waste.

At this time, the oil accumulated in the oil chamber 18 is combined and discharged. In addition, in the case shown in Fig. 6, since the seal plate 16 is formed symmetrically, there is no need to fix it with a dowel pin, making it even simpler. Even if negative pressure occurs in the compressor blade chamber 5, which has been supplied with a large amount of lubricating oil to the thrust bearing, by surrounding the thrust bearing with a seal plate, the compressor blade chamber 5 The effect is that used lubricating oil can be efficiently discharged without causing oil leakage.

[Brief explanation of drawings]

Figure 1 is a sectional view of a conventional compressor side shaft sealing device, Figure 2
The figure is a sectional view taken along A-N in Figure 1, and Figure 3 is a sectional view taken along B-B'' in Figure 2.
4 is a sectional view of a main part of a compressor side shaft sealing device which is an embodiment of the present invention, FIG. 5 is a sectional view taken along line C-C'' in FIG. 4, and FIG. 7 is a cross-sectional view taken along line DD'' in FIG. 6, and FIGS. 8 and 9 are a sectional view of a compressor-side shaft sealing device which is a modification of FIG. 6. FIG. 7 is a cross-sectional view of the device corresponding to FIG. 7;

Claims (1)

[Scope of Claims] 1(a) A rotating shaft having a turbine wheel at one end and a compressor wheel at the other end; (b) A radial bearing installed in a center housing to rotatably support the rotating shaft. (c) a thrust collar interposed on the outer periphery of the rotating shaft between the radial bearing and the compressor impeller; (d) a thrust collar fitted into the thrust groove of the thrust collar, with one end side facing the side surface of the center housing; (e) a drain port formed in the center housing for discharging lubricating oil supplied to the thrust bearing; (f) the thrust collar; (g) a seal plate having a bent portion that surrounds the outer periphery of the compressor-side disk formed in the compressor side and the compressor-side end surface of the thrust bearing, and is in contact with the outer circumferential surface of the thrust bearing; A compressor side shaft sealing device for a turbocharger, comprising a seal plate separation preventing means for preventing the bent portion from separating from the outer circumferential surface of the thrust bearing. 2. A patent claim in which the bent portion has its tip fitted into a guide groove provided on an end surface of the center housing on the compressor side, and its lower portion forms a partition plate that projects into the drain port. A compressor-side shaft sealing device for a turbocharger according to item 1. 3. The compressor-side shaft sealing device for a turbocharger according to claim 1, wherein the bent portion is an annular portion shorter than the thickness of the thrust bearing.