JPH0447387Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an oil seal structure for an exhaust turbocharger.

[Conventional technology]

Normally, the rotating shaft of an exhaust turbocharger uses an oil-lubricated bearing, and therefore an oil seal is required to prevent oil flowing out from the bearing from flowing out to the exhaust turbine wheel side. In order to achieve such an oil seal, a piston ring is usually fitted onto the turbine rotating shaft and the piston ring provides an oil seal, as described in, for example, Japanese Utility Model Application Publication No. 49-39735. . In addition, as described in the above publication, a seal ring is fitted onto the turbine rotating shaft, and a labyrinth structure is formed on the turbine rotating shaft on both sides of the seal ring, and this labyrinth structure allows the oil to be kept away from the seal ring. Seal structures are known.

[Problem that the invention attempts to solve]

However, when piston rings are used, there is a problem in that oil leaks from gaps between the split ends of the piston rings or from gaps around the piston rings. When oil leaks in this way, not only does oil consumption increase, but also the oil is exhausted into the exhaust passage, causing a problem of deterioration of exhaust emissions.

Furthermore, even in the case of a labyrinth structure, if the rotational speed of the turbine rotating shaft decreases, the force that moves oil away from the seal ring weakens, causing oil to leak to the exhaust turbine wheel side via the seal ring, causing a similar problem.

[Means for solving problems]

In order to solve the above problems, according to the present invention, a ring is fitted on the turbine rotating shaft on the back side of the turbine wheel, and an annular disk-shaped elastic heat insulating plate is arranged on the back side of the turbine wheel, and the outer peripheral edge of the heat insulating plate is is supported by the housing, and a ring-shaped sealing member is fixed to the inner peripheral edge of the heat insulating plate, and a spring member is inserted between the heat insulating plate and the housing to press the sealing member onto the side wall surface of the ring.

〔Example〕

Referring to the drawing, 1 is an exhaust turbocharger, 2 is a turbine housing, 3 is an exhaust scroll chamber, 4 is an exhaust outlet, 5 is a center housing, and 6 is rotatable by the center housing 5 via an oil-lubricated floating bearing 7. 8 is a turbine wheel supported by a turbine rotating shaft;
9 indicates a turbine blade, and 10 indicates a shroud. The turbine rotating shaft 6 has a large diameter part 6a, a middle diameter part 6b, and a diameter part 6a whose diameter gradually decreases as the distance from the turbine wheel 8 increases, on the back surface of the turbine wheel 8.
It has a small diameter portion 6c, and a floating bearing 7 is attached to the small diameter portion 6c. A wear-resistant ring 11 with a short cross-section is fitted onto the intermediate diameter portion 6b, and this ring 11 is attached to the stepped portion 6d between the intermediate diameter portion 6b and the large diameter portion 6a.
is brought into contact with.

On the other hand, on the back surface of the turbine wheel 8, an annular disk-shaped resilient heat insulating plate 12 is arranged.
The outer peripheral edge of the heat insulating plate 12 is fixedly supported together with the shroud 10 between the housings 2 and 5.
A ring-shaped sealing member 13 made of ceramic such as SiCN ₄ is fixed on the inner peripheral edge of the ring 2 . In addition, a plurality of grooves 14 are formed on the inner circumferential wall surface of the center housing 5 facing the inner circumferential edge of the heat insulating plate 12.
are bored, and spring members 15 are inserted between the grooves 14 and the inner peripheral edge of the heat insulating plate 12, respectively. It is preferable to use a coil spring made of ceramic with high heat resistance as the spring member 15. The sealing member 13 is arranged facing the side wall surface of the ring 11,
The spring force of the spring member 15 presses the ring 11 onto the side wall surface.

Exhaust gas discharged from an internal combustion engine (not shown) is guided into the exhaust scroll chamber 3, and then this exhaust gas flows out at high speed from the exhaust outlet 4 and imparts rotational force to the turbine wheel 8 before exiting the exhaust gas outlet. It is discharged from 16. As a result, the turbine rotating shaft 6 is rotated around the axis 17 at high speed. On the other hand, oil is constantly supplied to the floating bearing 7 from an oil supply passage (not shown), and a portion of the oil flowing out from the floating bearing 7 is contained in the oil chamber 18 formed between the heat insulating plate 12 and the center housing 5. flows into. The oil chamber 18 is therefore filled with oil.

By the way, as mentioned above, the heat insulating plate 12 is made of an elastic material, and the sealing member 13 can be pressed onto the side wall surface of the ring 11 by the spring force of the heat insulating plate 12 itself. In the embodiment shown in the drawings, the seal member 13 is brought into pressure contact with the side wall surface of the ring 11 by the spring force of the spring member 15 in addition to the spring force of the heat insulating plate 12 itself. Therefore, the space between the seal member 13 and the ring 11 is completely sealed, and thus the oil in the oil chamber 18 can be completely prevented from flowing out to the turbine wheel 8 side.

[Effect of idea]

By bringing the seal member attached to the heat insulating plate into pressure contact with the ring attached to the rotating shaft, it is possible to completely prevent oil from flowing out to the turbine wheel side.

[Brief explanation of the drawing]

The figure is a side sectional view of the vicinity of the turbine wheel of the exhaust turbocharger. 2... Turbine housing, 5... Center housing, 6... Turbine rotating shaft, 8... Turbine wheel, 11... Ring, 12... Heat insulating plate,
13... Seal member, 15... Spring member.

Claims (1)

[Scope of utility model registration request] A ring is fitted onto the turbine rotating shaft on the back side of the turbine wheel, and an annular disc-shaped elastic heat insulating plate is arranged on the back side of the turbine wheel, and the outer peripheral edge of the heat insulating plate is supported by the housing, and the inner peripheral edge of the heat insulating plate is supported by the housing. An oil seal structure for an exhaust turbocharger, wherein a ring-shaped seal member is fixed to the ring, and a spring member is inserted between the heat insulating plate and the housing to press the seal member against the side wall surface of the ring.