Turbocharger sealing structure

Abstract

The objective is to provide a turbocharger sealing structure that can suppress exhaust gas leakage. [Solution] A seal structure for a turbocharger comprising: a drive shaft extending from the outside to the inside of an exhaust pipe; a bearing provided around the drive shaft; and an arm provided inside the exhaust pipe, connected to the drive shaft, and rotating together with the drive shaft, wherein the first surface of the bearing faces the second surface of the arm, and when the arm moves toward the bearing, the second surface contacts the first surface, and the first surface has either a curved surface or a tapered shape, and the second surface has either a curved surface or a tapered shape.

Description

Technical Field

[0001] The present invention relates to a seal structure of a turbocharger.

Background Art

[0002] The turbocharger is provided with vanes and a waste gate valve (WGV). Techniques for sealing an arm driven by the vanes have been developed (for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the exhaust system, considering thermal expansion, a clearance may be provided between components. There is a risk that exhaust may flow out through the clearance. Therefore, an object is to provide a seal structure of a turbocharger capable of suppressing the outflow of exhaust.

Means for Solving the Problems

[0005] The above object can be achieved by a seal structure of a turbocharger including a drive shaft extending from the outside to the inside of an exhaust pipe, a bearing provided around the drive shaft, and an arm provided in the exhaust pipe, connected to the drive shaft, and rotating together with the drive shaft, wherein a first surface of the bearing faces a second surface of the arm, and when the arm moves toward the bearing, the second surface contacts the first surface, and the first surface has one of a curved surface or a tapered shape, and the second surface has the one of the curved surface or the tapered shape.

Effects of the Invention

[0006] This provides a turbocharger sealing structure that can suppress exhaust gas leakage. [Brief explanation of the drawing]

[0007] [Figure 1] Figure 1 is a schematic diagram illustrating a seal structure according to the first embodiment. [Figure 2] Figure 2 illustrates a seal structure related to a comparative example. [Figure 3] Figure 3(a) is a schematic diagram illustrating a seal structure according to the second embodiment. Figure 3(b) is a schematic diagram illustrating a seal structure according to the third embodiment. [Modes for carrying out the invention]

[0008] <First Embodiment> The seal structure of a turbocharger according to the first embodiment will be described below with reference to the drawings. Figure 1 is a schematic diagram illustrating a seal structure 100 according to the first embodiment. The seal structure 100 is mounted on a vehicle and applied to a turbocharger. The seal structure 100 includes a rod 10, a link 12, a pin 14 (drive shaft), a bush 16 (bearing), an arm 18, and a valve 20. The -X and +X directions in Figure 1 represent the direction in which the pin 14 extends.

[0009] The area -X from the wall 11 of the exhaust pipe is the outside of the exhaust pipe. The area +X from the wall 11 is the inside of the exhaust pipe. The arm 18 and valve 20 are located inside the exhaust pipe. The rod 10 and link 12 are located outside the exhaust pipe. The pressure outside the exhaust pipe is approximately equal to atmospheric pressure. The pressure inside the exhaust pipe can be higher than atmospheric pressure.

[0010] A rod 10 is attached to one end of a link 12. A pin 14 is attached to the other end of the link 12. A bush 16 is, for example, cylindrical, with the pin 14 inside. The pin 14 is surrounded by the bush 16. The bush 16 is inserted into the wall 11 of the exhaust pipe. The pin 14 and bush 16 extend from the outside to the inside of the exhaust pipe.

[0011] Pin 14 extends from link 12 to arm 18. The -X end of pin 14 is connected to link 12, and the +X end is connected to arm 18. Valve 20 is the valve body of WGV and is connected to arm 18.

[0012] The arm 18 includes part 40 and part 42. Part 42 protrudes from part 40 on the -X side and is connected to pin 14. A valve 20 is mounted on part 40. Parts 40 and 42 are a single unit and are made of a metal such as stainless steel.

[0013] The dashed line in Figure 1 is a hypothetical line segment representing axis A. Pin 14 rotates around axis A. When a force is applied to rod 10, the force is also applied to pin 14 through link 12, causing pin 14 to rotate. Arm 18 rotates with pin 14. Since valve 20 is connected to arm 18, it rotates with arm 18. This causes WGV to open and close.

[0014] High-temperature exhaust gas flows through the vehicle's exhaust system. This can cause parts to expand due to thermal expansion. To account for this thermal expansion, clearances are provided between the parts. As shown in Figure 1, there is a gap 22 (clearance) between the outer surface of the pin 14 and the inner surface of the bush 16. There is also a gap 24 (clearance) between the +X end face of the bush 16 and the -X end face of the arm 18.

[0015] The surface 30 (first surface) of the bush 16 facing the arm 18 is a curved surface that is recessed towards the -X side. The surface 32 (second surface) of the arm 18 facing the bush 16 is a curved surface that is convex towards the -X side. The arm 18 is pushed towards the -X side by the exhaust pressure. Surface 32 of the arm 18 comes into contact with surface 30 of the bush 16.

[0016] (Comparative example) FIG. 2 is a diagram illustrating a seal structure 110 according to a comparative example. A piston ring 15 is provided on a pin 14. A surface 30 of the bush 16 facing the arm 18 and a surface 32 of the arm 18 facing the bush 16 are perpendicular to the axis A. As described above, since there is a gap 22 between the bush 16 and the pin 14, the pin 14 may tilt. The arm 18 tilts together with the pin 14. The surface 32 of the arm 18 is no longer parallel to the surface 30 of the bush 16.

[0017] In the comparative example, when the pin 14 and the arm 18 tilt and the arm 18 moves to the -X side, the surface 32 of the arm 18 and the surface 30 of the bush 16 contact at a point. The surfaces 32 and 30 do not adhere closely, and a gap 24 remains between these surfaces. Therefore, the exhaust gas flows out of the exhaust pipe through the gap 24 and the gap 22.

[0018] According to the first embodiment, as shown in FIG. 1, the surface 30 of the bush 16 and the surface 32 of the arm 18 are curved surfaces. When the arm 18 moves to the -X side, the surface 32 is fitted into the surface 30, and these surfaces adhere closely. Since the surfaces 30 and 32 adhere closely, the gap 24 is blocked. Since the space between the arm 18 and the bush 16 is sealed, the outflow of the exhaust gas can be suppressed.

[0019] The surfaces 30 and 32 are curved surfaces such as spherical surfaces for example. The radius of curvature of the surface 30 may be about the same as the radius of curvature of the surface 32. By engaging the surfaces 30 and 32, the sealing performance is improved. Since components such as a ring for sealing do not need to be added, the cost can be reduced and the assembling property is improved.

[0020] Since the arm 18 is pressed against the -X side, the surface 32 of the arm 18 and the surface 30 of the bush 16 contact, and the arm 18 slides with respect to the bush 16. Processing may be performed to enhance the sliding property and reduce the friction between the surfaces. For example, dimpling or thermal spraying may be performed on the surfaces 30 and 32.

[0021] <Second Embodiment> FIG. 3(a) is a schematic diagram illustrating a seal structure 200 according to the second embodiment. Descriptions of the same configurations as those in the first embodiment are omitted. The surface 30 of the bush 16 and the surface 32 of the arm 18 have a tapered shape and taper towards the -X side.

[0022] According to the second embodiment, when the arm 18 moves to the -X side, the tapered surfaces 30 and 32 come into contact with each other. The sealing performance is improved, and the outflow of exhaust can be suppressed.

[0023] <Third Embodiment> FIG. 3(b) is a schematic diagram illustrating a seal structure 300 according to the third embodiment. Descriptions of the same configurations as those in the first or second embodiment are omitted. The part 42 is a separate component from the part 40 and is attached to the part 40. The part 40 is formed of an alloy such as stainless steel, for example. The part 42 is formed of a copper-based metal, for example.

[0024] According to the third embodiment, since the part 42 is a copper-based material, seizure can be prevented and the sliding property is improved. The surface 32 of the part 42 and the surface 30 of the bush 16 may be curved surfaces or may have a tapered shape. The sealing performance is improved.

[0025] Although the preferred embodiments of the present invention have been described in detail above, the present invention is not limited to such specific embodiments, and various modifications and changes are possible within the scope of the gist of the present invention described in the claims.

Description of Reference Numerals

[0026] 10 Rod, 11 Wall, 12 Link, 14 Pin, 15 Piston Ring, 16 Bush, 18 Arm, 20 Valve, 22, 24 Gap, 30, 32 Surface, 40, 42 Part, 100, 110, 200, 300 Seal Structure

Claims

[Claim 1] A drive shaft that extends from the outside to the inside of the exhaust pipe, A bearing provided around the aforementioned drive shaft, The exhaust pipe is provided with an arm that is connected to the drive shaft and rotates together with the drive shaft, The first surface of the bearing faces the second surface of the arm, When the arm moves toward the bearing, the second surface comes into contact with the first surface. The first surface has either a curved or tapered shape, The second surface is a seal structure for a turbocharger having one of the following shapes: a curved surface or a tapered surface.

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