JP2848027B2 - Structure of oil seal for turbocharger - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oil seal for a turbocharger for preventing a lubricant supplied to a bearing supporting the drive shaft from leaking out of the housing in a housing of the drive shaft of the turbocharger. Related to the structure.

[0002]

2. Description of the Related Art Since the drive shaft of a turbocharger rotates at a high speed, bearings of a type requiring lubricating oil are generally used for radial and axial positioning of the shaft. Normally, engine oil is used as the lubricating oil, and it is necessary to return the lubricating oil to the oil pan without leaking out of the drive shaft housing by oil seals provided on the compressor side and the turbine side in the drive shaft housing. .

[0003] In particular, the oil seal on the compressor side
When the throttle valve is suddenly opened, the response of the compressor wheel may be delayed, resulting in a negative pressure in the intake passage. If the sealing performance cannot be guaranteed against the negative pressure, the consumption of engine oil increases. In addition, the leaked lubricating oil is supplied into the cylinder, causing abnormal combustion of the engine and generation of white smoke.

A structure of such an oil seal is shown in FIG. 2 in Japanese Utility Model Laid-Open No. 60-116035. FIG. 1 shows the compressor side of the turbocharger, where 1 is a compressor wheel and 2 is a drive shaft.

[0005] The drive shaft 2 is positioned by a radial bearing 3 and a thrust bearing 4. Both bearings 3, 4 require lubricating oil,
As this lubricating oil, engine oil is supplied to the surfaces of the bearings 3 and 4 through a passage 5 a provided in the housing 5.

[0006] The structure of the oil seal shown in the figure is that a first groove (right side in the figure) and a second groove (left side in the figure) and a ring-shaped protrusion therebetween are provided between the step portion of the drive shaft 2 and the compressor wheel 1. 6a is provided, and a housing 5 is provided.
Is fixed to a deflector 8 sandwiched by a hollow insert 7 and a thrust bearing 4.
The first seal ring 9 fitted in the groove abuts, the second seal ring 10 fitted in the second groove abuts on the compressor side end of the insert 7, and the vertical inner surface of this end and the The vertical surface of the ring-shaped protrusion 6 a is opposed to the vertical surface with a small gap 11. This gap 1
1 forms a labyrinth seal for preventing leakage by applying a radially outward centrifugal force to the oil flowing into the gap 11 because the ring-shaped projection 6a rotates together with the drive shaft 2.

With such a structure, each bearing 3,
Of the oil that has lubricated the surface of 4, the oil sealed with the first seal ring 9 is returned to the oil pan through a discharge port 8a provided below the deflector 8, passes through the first seal ring 9, and Of the insert 7 is returned to the oil pan through a discharge port (not shown) provided below the internal space 7a of the insert 7. What further passes through the labyrinth seal is sealed by the second seal ring 10.

[0008]

In the above-described prior art, the first and second seal rings have an opening for allowing the collar to be inserted into the groove of the collar, and the outflow of oil through the opening is performed. Due to its presence, it is not possible to obtain very high sealing performance.

Accordingly, in order to make the leakage of oil out of the housing of the drive shaft negligible, the above-mentioned labyrinth seal functions sufficiently and the amount of oil reaching the second seal ring must be considerably reduced. Must. The labyrinth seal assures good sealing performance if the aforementioned clearance dimensions are properly formed, but the drive shaft has a slight axial play to allow rotation, and this play causes As the drive shaft moves in the axial direction, the size of the clearance of the labyrinth seal becomes inappropriate, and the amount of oil passing through the labyrinth seal increases,
As a result, the amount of oil leaking out of the housing through the second seal ring increases.

Accordingly, an object of the present invention is to provide an oil seal structure for a turbocharger using a labyrinth seal capable of obtaining good sealing performance even if the drive shaft moves in the axial direction due to play.

[0011]

In order to achieve the above-mentioned object, a structure of an oil seal for a turbocharger according to the present invention comprises an elastic member provided on one of a drive shaft side of the turbocharger and a housing side of the drive shaft. And a ring member having a ring-shaped projection extending toward the other while being held by the elastic member and a ring-shaped projection extending toward the other. It has a ring-shaped side surface perpendicular to each other and surfaces facing each other, and is fixed to the other of the drive shaft side or the housing side so that each surface and the ring-shaped side surface form a gap of a predetermined dimension. And two collar members.

[0012]

According to the structure described above, a clearance appropriately provided between the ring-shaped both side surfaces of the ring member and the surface of each of the collar members opposing the ring member forms a labyrinth seal. Is held on the drive shaft side or the housing side by the frictional force of the elastic member, is immovable in the radial direction, and is movable in the axial direction, so that when the drive shaft moves in the axial direction due to play, The ring member slides freely in the axial direction with respect to the member held by the filling oil, so that the gap formed between the ring member and the collar member can always be maintained at a predetermined size, thereby achieving good sealing performance. It is possible to guarantee.

[0013]

FIG. 1 shows an embodiment of the structure of an oil seal for a turbocharger according to the present invention. This figure is a sectional view on the compressor side like FIG. 2 showing a conventional example, and the same members as those in FIG. 2 are indicated by the same reference numerals.

The insert 7 'fixed to the housing 5 of this embodiment has a surface facing the drive shaft 2 in the internal space.
Ring-shaped elastic member 1 such as rubber O-ring
2 is inserted into the groove 7'b. Outside the groove, oil after lubricating the bearings 3 and 4 is stored and returned to an oil pan from a discharge port (not shown) provided at a lower portion. Oil chamber 7'c is provided, and the oil chamber 7'c is closed by a spacer 13 for preventing backflow of the oil flowing into the oil chamber 7'c. Further, the compressor side end has a shape in which it comes into contact with a seal ring 10 inserted into a collar member 6 'fixed to the drive shaft 2 as in the conventional case, and the outside thereof has the interior space as in the conventional case. An annular passage 7'a for returning the oil to the oil pan is formed.

A ring member 14 having a ring-shaped projection 14a extending in the direction of the drive shaft 2 is provided in contact with the elastic member 12 inserted into the groove 7'b of the insert 7 '.
The collar member 6 'having a surface opposed to the both sides of the ring-shaped projection 14a perpendicular to the axis of the drive shaft 2 has a predetermined surface. It is fixed to the drive shaft 2 so as to form dimensional gaps 11a and 11b. The collar member 6 'is provided with a compressor side part 6'a to enable this assembly.
And a turbine-side portion 6'b.

The thrust bearing 4 has a ring shape with a part omitted, so that it can be inserted into the groove of the turbine-side portion 6'b of the collar member 6 '. The outer part of the C-shaft ring 1 is provided with the insert 7 in the housing 5.
5, the insert 7 and the housing 5
And is sandwiched by.

As described above, the drive shaft 2 is axially held by the turbine-side portion 6'b of the collar member 6 fixed to the drive shaft 2 and the thrust bearing 4 fixed to the housing 5 in the axial direction. Is positioned.

The oil seal having such a structure is provided with an oil supply passage (not shown) provided in the housing 5 as in the prior art.
After lubricating the bearings 3 and 4 with the lubricating oil supplied thereto, centrifugal force is applied by the turbine-side portion 6 ′ b of the collar member 6 ′ that rotates together with the drive shaft 2, so that the insert 7 ′ and the spacer 13 The oil reaches the oil chamber 7'c through the gap therebetween, and is returned to the oil pan from a discharge port provided at a lower portion thereof.

A part of the lubricating oil flows into a gap 11b of a predetermined size provided between the ring member 14 and the turbine-side portion 6'b of the collar member 6 '. This gap 11b serves as the above-mentioned labyrinth seal, and performs good sealing because it is immovable in the radial direction with respect to the insert 7 fixed to the housing 5 by frictional force.

Since the gap between the ring member 14 and the insert 7 'is sealed by the elastic member 12, no oil leaks. As described above, the elastic member 12 cannot be used for a sliding portion because of its high frictional resistance. However, when it is used for an immovable portion as in this embodiment, it is generally known that a good sealing performance is guaranteed. Have been.

When the drive shaft 2 is stopped, the clearance 1 between the ring member 14 and the turbine-side portion 6'b of the collar member 6 'is reduced.
1b, there is an oil spill due to no centrifugal force acting on the oil, but this oil must pass through the relatively long gaps 11a, 11b. The amount flowing out of the gap 11a between the ring member 13 and the ring member 13 is small.

This oil is supplied to the annular passage 7 'provided at the end of the insert 7' on the compressor side as the drive shaft 2 rotates.
a, and is returned to the oil pan by a discharge port provided at a lower portion of the annular passage 7'a, so that the amount reaching the seal ring 10 is further reduced.

As described above, the gap between the ring member 14 and each of the portions 6'a and 6'b of the collar member 6 'is always filled with the oil, so that the drive shaft 2 can be rotated. Due to axial play provided between the thrust bearing 4 and the turbine-side portion 6'b of the collar member 6 ', even if the drive shaft 2 moves in the axial direction, the ring member 1
Since the member 4 is held by the insert 7 'fixed to the housing 5 by the elastic force of the elastic member 12, the ring member 13 is filled with the oil filling the gaps 11a, 11b on both sides of the collar member 6'. And 6'b, sliding in the axial direction, and the gaps 11a, 1 optimally provided to ensure good sealing performance of the labyrinth seal.
The size of 1b is not changed.

Therefore, the labyrinth seal always maintains a good sealing performance, and the amount of oil reaching the seal ring 10 can be made very small because the delay in the compressor passage 1 in the intake passage causes the oil to flow. Even if the pressure becomes negative, the amount can be sufficiently sealed by the seal ring 10 having an abutment, and leakage of oil into the intake passage can be almost completely prevented.

In this embodiment, the ring member 14 is held on the housing 5 side.
Is provided on the drive shaft 2 side, and the ring member 14 is rotated together with the drive shaft 2 by the frictional force, so that each of the collar members 6′a,
It is clear that the same effect can be obtained even if 6'b is fixed to the housing 5 side, and if the material of the elastic member 12 is made of a material having high heat resistance, it can be used as an oil seal structure on the turbine side. .

[0026]

As described above, according to the oil seal structure for a turbocharger of the present invention, the axial movement of the drive shaft caused by the axial play absolutely necessary to enable the rotation of the drive shaft is achieved. Even if it occurs, the dimension of the appropriately provided gap of the labyrinth seal is kept constant without change, and the high sealing performance of the labyrinth seal is always guaranteed, so that oil leakage to the compressor side or turbine side is , Can be almost completely eliminated.

[Brief description of the drawings]

FIG. 1 is a sectional view of a compressor side showing a structure of an oil seal for a turbocharger according to the present invention.

FIG. 2 is a sectional view similar to FIG. 1 showing a conventional example.

[Explanation of symbols]

 2 ... drive shaft 3 ... radial bearing 4 ... thrust bearing 6, 6 '... collar member 7, 7' ... insert 10 ... seal ring 12 ... elastic member 14 ... ring member

Claims (1)

(57) [Claims] At least one of a drive shaft side of a turbocharger and a housing side of the drive shaft is held by a frictional force of an elastic member, and a seal structure therebetween is formed by the elastic member. A ring member having an extending ring-shaped protrusion, and ring-shaped side surfaces perpendicular to the axis of the drive shaft of the ring-shaped protrusion, each having a surface facing each other, the drive shaft side or the housing; The structure of an oil seal for a turbocharger, comprising, on the other side, two collar members each of which is fixed so that each of the surfaces and the ring-shaped side surfaces form a gap having a predetermined size.