Sealing structure of turbocharger

Abstract

A sealing structure for a turbocharger according to the present invention is provided with: a rotating member including a rotating shaft of the turbocharger and a rotating impeller provided on one end side of the rotating shaft; a stationary member including a housing for accommodating the rotating member; a bearing that rotatably supports the rotating shaft; and a sealing member provided in a sealing gap formed between the rotating member and the stationary member and communicating a first space for accommodating the rotating impeller and a second space for accommodating the bearing. The stationary member includes a stationary-side inner peripheral surface defining the seal gap and a stationary-side end surface extending in the radial direction of the rotating shaft from an edge on the second space side on the stationary-side inner peripheral surface, and the stationary-side end surface includes an inclined surface provided within a predetermined circumferential range below the axis of the rotating shaft. The second space is inclined toward the second space in the axial direction of the rotating shaft as the second space is inclined downward from the edge of the stationary side inner peripheral surface on the second space side.

Description

Technical Field

[0001] This invention relates to a sealing structure for a turbocharger. Background Technology

[0002] A turbocharger comprises: a rotor (rotating body) including a rotating shaft, a turbine impeller mounted on one side of the rotating shaft, and a compressor impeller mounted on the other side of the rotating shaft; a bearing that rotatably supports the portion between the turbine impeller and the compressor impeller on the rotating shaft; and a housing (stationary part) for housing the rotor and bearing. Since the bearings of a turbocharger support the high-speed rotating shaft, they are prone to generating high temperatures, and there is a risk of sintering when insufficient lubrication is present. Therefore, lubricating oil is supplied to the bearings for lubrication or cooling. To prevent leakage of lubricating oil supplied to the bearings to the compressor side or turbine side, some turbochargers include sealing rings that seal between the outer surface of the rotating body such as the rotor and the inner surface of the stationary part such as the housing (for example, see Patent Document 1).

[0003] Previous technical documents Patent documents Patent Document 1: Japanese Patent Application Publication No. 2008-232124 Summary of the Invention

[0004] The technical problem to be solved by the invention In turbochargers equipped with sealing mechanisms using sealing rings, there is a risk of lubricant leakage. Specifically, lubricant accumulates in the space between the outer surface of the rotating body on which the sealing ring is installed and the inner surface of the stationary part, posing a risk that the lubricant accumulated in the space may leak through the sealing ring into a space on the opposite side.

[0005] In view of the above, at least one embodiment of the present invention aims to provide a sealing structure for a turbocharger capable of suppressing lubricating oil leakage.

[0006] means for solving technical problems At least one embodiment of the present invention relates to a turbocharger sealing structure comprising: The rotating component includes at least the rotating shaft of the turbocharger and a rotating impeller disposed at one end of the rotating shaft; A stationary component, including at least a housing for accommodating the rotating component; Bearings, which rotatably support the rotating shaft; and A sealing component is disposed in a sealing gap formed between the rotating component and the stationary component, and the sealing gap connects a first space for accommodating the rotating impeller and a second space for accommodating the bearing. The rotating component includes at least a rotating outer peripheral surface for defining the sealing gap. The stationary component includes a stationary side inner peripheral surface for defining the sealing gap and a stationary side end surface extending radially from the edge of the second spatial side on the stationary side inner peripheral surface along the rotation axis. The stationary side end face includes an inclined surface disposed within a predetermined circumferential range below the axis of the rotation axis, and inclined towards the second spatial side in the axial direction of the rotation axis as the edge of the second spatial side of the stationary side inner circumferential surface moves downward.

[0007] Invention Effects According to at least one embodiment of the present invention, a sealing structure for a turbocharger capable of suppressing lubricating oil leakage is provided. Attached Figure Description

[0008] Figure 1 It is a schematic cross-sectional view showing a section taken along the axis of a turbocharger having a sealing structure according to one embodiment of the turbocharger.

[0009] Figure 2 It is a schematic cross-sectional view showing a section taken along the axis of the sealing structure of a turbocharger according to one embodiment.

[0010] Figure 3 This is a schematic diagram showing the state of the sealing structure of a turbocharger according to one embodiment, as viewed from the second space side.

[0011] Figure 4 This is a schematic diagram showing the state near the inclined surface in the sealing structure of a turbocharger according to one embodiment, viewed from above.

[0012] Figure 5 It is a schematic cross-sectional view showing a section taken along the axis of the sealing structure of a turbocharger according to one embodiment. Detailed Implementation

[0013] Hereinafter, several embodiments of the present invention will be described with reference to the accompanying drawings. However, the dimensions, materials, shapes, relative arrangements, etc., of the constituent components described in the embodiments or shown in the drawings are not intended to limit the scope of the present invention, but are merely illustrative examples.

[0014] (Turbocharger) Figure 1This is a schematic cross-sectional view showing a section taken along the axis of a turbocharger having a sealing structure according to one embodiment of the turbocharger. Turbocharger 1 as shown... Figure 1 As shown, it includes: a rotating shaft 11; a turbine impeller 12A disposed at one end of the rotating shaft 11; a compressor impeller 12B disposed at the other end of the rotating shaft 11; a bearing 13 for rotatably supporting the rotating shaft 11; and a housing 14 for accommodating the rotating shaft 11, the turbine impeller 12A, the compressor impeller 12B, and the bearing 13.

[0015] The bearing 13 is supported by the housing 14. The rotating shaft 11 is supported by the bearing 13 between the turbine impeller 12A and the compressor impeller 12B, and can rotate about the axis LA of the rotating shaft 11.

[0016] Hereinafter, the direction in which the axis LA of the rotating shaft 11 extends is defined as the axial direction of the rotating shaft 11 (turbocharger 1), and the direction orthogonal to the axis LA is defined as the radial direction of the rotating shaft 11 (turbocharger 1). In the axial direction of the rotating shaft 11 (turbocharger 1), the side of the turbine impeller 12A relative to the compressor impeller 12B is designated as the turbine side, and the side of the compressor impeller 12B relative to the turbine impeller 12A is designated as the compressor side.

[0017] The turbine impeller 12A is configured to rotate using energy from exhaust gas from the engine that is guided to the turbine impeller 12A. The compressor impeller 12B rotates in conjunction with the rotation of the rotating shaft 11 and the turbine impeller 12A. The turbocharger 1 is configured to compress gas (e.g., air) guided to the compressor impeller 12B by the rotation of the compressor impeller 12B, thereby increasing the density of the gas and delivering it to its supply destination (e.g., the aforementioned engine).

[0018] (Sealing structure of turbocharger) Figure 2 It is a schematic cross-sectional view showing a section taken along the axis of the sealing structure of a turbocharger according to one embodiment. Figure 2 The text is a jumbled collection of characters and phrases, seemingly from different sources and lacking coherent sentences. A direct translation wouldn't be meaningful. Figure 1 The area enclosed by a double-dotted line. Figure 3 This is a schematic diagram showing the state of the sealing structure of a turbocharger according to one embodiment, as viewed from the second space side. Figure 4 This is a schematic diagram showing the state near the inclined surface in the sealing structure of a turbocharger according to one embodiment, viewed from above. The sealing structure 2 of the turbocharger according to several embodiments is a sealing structure provided on the turbocharger 1 to suppress leakage of lubricating oil in the turbocharger 1. The sealing structure 2 of the turbocharger is as follows... Figure 1 and Figure 2As shown, it includes: a rotating component 3; a stationary component 4 that houses the rotating component 3; a sealing component 5 disposed in a sealing gap 20 formed between the rotating component 3 and the stationary component 4; and the aforementioned bearing 13.

[0019] (Rotating parts and stationary parts) The rotating component 3 is configured to rotate when driving the turbocharger 1. The rotating component 3 includes at least a rotating impeller 12 disposed on the rotating shaft 11 and at one end of the rotating shaft 11. The stationary component 4 is configured to remain stationary (not rotate) even when the rotating component 3 rotates while driving the turbocharger 1. The stationary component 4 includes at least a housing 14.

[0020] The stationary component 4 (housing 14) is used to accommodate the rotating component 3 and the bearing 13. Inside the stationary component 4 (housing 14), the aforementioned sealing gap 20, a first space 21 for accommodating the rotating impeller 12, and a second space 22 for accommodating the bearing 13 are formed. The sealing gap 20 is located axially along the rotating shaft 11, between the first space 21 and the second space 22, and connects the first space 21 and the second space 22.

[0021] The rotating component 3 has a rotating-side outer peripheral surface 31 for defining the sealing gap 20. The stationary component 4 has a stationary-side inner peripheral surface 41 for defining the sealing gap 20. The stationary-side inner peripheral surface 41 is located radially outward of the rotating axis 11, which is closer to the rotating-side outer peripheral surface 31 than the rotating-side outer peripheral surface 31, and is opposed to the rotating-side outer peripheral surface 31 across the sealing gap 20 which is formed in an annular shape.

[0022] stationary component 4, such as Figure 2 As shown, a stationary end face 43 extends radially outward from the edge 42 on the second space 22 side of the stationary inner peripheral surface 41 along the rotation axis 11. The rotating component 3 is as follows... Figure 2 As shown, it can have a rotating side end face 33 that extends radially toward the inner side of the rotation axis 11 from the edge 32 of the second space 22 side on the outer peripheral surface 31 of the rotating side.

[0023] (Sealing components) The sealing component 5 is configured to seal between the stationary inner circumferential surface 41 and the rotating outer circumferential surface 31. In the illustrated embodiment, the sealing component (sealing ring) 5 is as follows: Figure 2 As shown, it is configured in a state where it is compressed between the stationary inner circumferential surface 41 and the rotating outer circumferential surface 31, with its outer circumferential surface abutting against the stationary inner circumferential surface 41 and its inner circumferential surface abutting against the rotating outer circumferential surface 31. Furthermore, as... Figure 1 and Figure 2As shown, an annular groove extending circumferentially along the rotation axis 11 for fitting a portion of the sealing member 5 may also be provided on at least one of the stationary side inner circumferential surface 41 or the rotating side outer circumferential surface 31.

[0024] (Lubricating oil system) The turbocharger 1 is configured to allow lubricating oil to flow into the bearing 13 or into the second space 22 that houses the bearing 13. Figure 1 In the illustrated embodiment, the housing 14 has a lubricating oil inlet 23 for introducing lubricating oil into its interior, a lubricating oil supply path 24 for introducing lubricating oil from the lubricating oil inlet 23 into the bearing 13, and a lubricating oil outlet 25 for discharging lubricating oil to the exterior of the housing 14. The lubricating oil supply path 24 is defined by the inner wall surface of the housing 14 and serves to connect the lubricating oil inlet 23 with the second space 22. The lubricating oil outlet 25 is located lower than the second space 22 and communicates with the lower part of the second space 22.

[0025] Lubricating oil introduced into the interior of housing 14 via lubricating oil inlet 23 is guided to bearing 13 through lubricating oil supply path 24. Most of the lubricating oil guided to bearing 13 flows downward in second space 22 and is discharged to the outside of housing 14 via lubricating oil outlet 25. Sometimes a portion of the lubricating oil guided to bearing 13 flows into sealing gap 20.

[0026] The sealing structure 2 of the turbocharger 1 according to several embodiments includes the aforementioned rotating component 3, the aforementioned stationary component 4, the aforementioned bearing 13, and a sealing component 5 disposed in the aforementioned sealing gap 20. The stationary component 4 includes the aforementioned stationary side inner peripheral surface 41 and the aforementioned stationary side end surface 43. The stationary side end surface 43 is as follows: Figure 2 and Figure 3 As shown, it includes an inclined surface 6 disposed within a defined circumferential range CR that is located lower than the axis LA of the rotation axis 11. The inclined surface 6 is inclined toward the second space 22 side in the axial direction of the rotation axis 11 (the direction in which the axis LA of the rotation axis 11 extends) as the edge 42 of the second space 22 side of the inner circumferential surface 41 on the stationary side moves downward.

[0027] stationary side end face 43 Figures 2-4 As shown, it also includes a flat surface 43A disposed in the region other than the region where the inclined surface 6 is formed. The flat surface 43A extends radially outward from the edge 42 on the second space 22 side of the inner peripheral surface 41 on the stationary side along the rotation axis 11. Figure 4As shown, in the edge 42 on the second space 22 side of the stationary inner circumferential surface 41, the inclined side edge 42A (the upper edge of the inclined surface 6), which is continuous with the inclined surface 6, has a concave curved shape as follows: it is recessed further towards the first space 21 side in the direction of the axis of rotation 11 than the flat surface side edge 42B (the inner circumferential edge of the stationary inner circumferential surface 41 of the flat surface 43A), which is continuous with the flat surface 43A. The inclined surface 6 has a lower edge 44 that is continuous with the flat surface 43A. The lower edge 44 is as follows: Figure 3 As shown, when viewed from the second space 22 side in the direction of the axis of rotation 11, it has a convex curved shape facing downward.

[0028] The lubricating oil flowing into the sealing gap 20 accumulates at the lower part of the sealing gap 20. At least a portion of the lubricating oil accumulated at the lower part of the sealing gap 20 flows down along the inclined surface 6 and is discharged into the second space 22.

[0029] According to the above structure, lubricating oil can be discharged from the lower part of the sealing gap 20 by means of the inclined surface 6 located within a predetermined circumferential range CR below the axis LA of the rotating shaft 11 of the stationary side end face 43, thus preventing lubricating oil from accumulating in the lower part of the sealing gap 20. By preventing lubricating oil from accumulating in the lower part of the sealing gap 20, the sealing structure 2 of the turbocharger can prevent lubricating oil from leaking from the sealing member 5 located in the sealing gap 20 to the first space 21 side (the side where the rotating impeller 12 is located).

[0030] In several implementation methods, such as Figure 1 As shown, the sealing structure 2A (2) of the turbocharger is used to suppress the leakage of lubricating oil from the second space 22 to the first space 21A (21) for housing the turbine impeller 12A. The rotating impeller 12 of the sealing structure 2A of the turbocharger is composed of the turbine impeller 12A described above. Figure 1 As shown, the space for accommodating the turbine impeller 12A, namely the first space 21A or the sealing gap 20A (20), is located on the turbine side axially closer to the rotating shaft 11 than the second space 22 for accommodating the bearing 13.

[0031] Rotational outer peripheral surface 31A (31) for example, Figure 1 As shown, it can be the outer peripheral surface of the boss portion protruding from the back of the turbine impeller 12A. The stationary side inner peripheral surface 41A (41) can be the inner wall surface of the housing 14 that faces the outer peripheral surface of the aforementioned boss portion of the turbine impeller 12A across the sealing gap 20A.

[0032] In several implementation methods, such as Figure 1As shown, the turbocharger's sealing structure 2B (2) is used to suppress the leakage of lubricating oil from the second space 22 to the first space 21B (21) which houses the compressor impeller 12B. The rotating impeller 12 of the turbocharger's sealing structure 2B is composed of the compressor impeller 12B described above. Figure 1 As shown, the space for accommodating the compressor impeller 12B, namely the first space 21B (21) or the sealing gap 20B (20), is located on the compressor side axially above the rotating shaft 11, which is closer to the second space 22 for accommodating the bearing 13.

[0033] Rotational outer peripheral surface 31B (31) for example, Figure 1 As shown, this can be the outer circumferential surface of the annular sleeve 15 of the turbocharger 1. The sleeve 15 is mounted on the rotating shaft 11 between the compressor impeller 12B (rotating impeller 12) and the bearing 13 in the axial direction of the rotating shaft 11, covering the outer circumference of the rotating shaft 11. The rotating component 3 may also include the sleeve 15. The stationary side inner circumferential surface 41B (41) can be the inner wall surface of the housing 14 that faces the outer circumferential surface of the sleeve 15 through the sealing gap 20B. Furthermore, the rotating side outer circumferential surface 31 can also be the outer circumferential surface of the rotating shaft 11.

[0034] Alternatively, the turbocharger 1 may also have both turbocharger sealing structures 2A and 2B. That is, the end face of the stationary side inner circumferential surface 41A that is continuous with the compressor side and the end face of the stationary side inner circumferential surface 41B that is continuous with the turbine side can each be a stationary side end face 43 including the aforementioned inclined surface 6.

[0035] In several implementation methods, such as Figure 3 As shown, the inclined surface 6 is formed at a position P1 that is vertically below the axis LA of the rotation axis 11. In this case, one end 61 of the inclined surface 6 within the circumferential range CR is positioned on one side in the horizontal direction relative to the axis LA of the rotation axis 11. The other end 62 of the inclined surface 6 within the circumferential range CR is positioned on the opposite side (the other side) in the horizontal direction relative to the axis LA of the rotation axis 11.

[0036] According to the above structure, by forming an inclined surface 6 at a position P1 that is vertically below the axis LA of the rotation shaft 11, the portion of the sealing gap 20 where lubricating oil accumulates, namely the lower region 20C including the position P1 that is vertically below the axis LA of the rotation shaft 11 of the sealing gap 20 (see reference), can be freed from the lubricating oil. Figure 3 The lubricating oil is discharged directly into the inclined surface 6. Therefore, compared with the inclined surface 6 excluding the vertically lower position P1, the inclined surface 6 including the vertically lower position P1 can effectively discharge lubricating oil from the lower part of the sealing gap 20 into the inclined surface 6.

[0037] In several implementation methods, such as Figure 3 As shown, the aforementioned inclined plane 6 slopes circumferentially from both ends 61 and 62 within the circumferential range CR toward the aforementioned vertically downward position P1.

[0038] According to the above structure, by providing a circumferential inclination on the inclined surface 6 from both ends 61, 62 within the circumferential range CR toward the vertically downward position P1, lubricating oil guided from the sealing gap 20 to the inclined surface 6 can flow toward the vertically downward position P1. As a result, lubricating oil accumulates near the vertically downward position P1 of the inclined surface 6, thereby promoting movement along the inclination of the inclined surface 6 caused by the weight of the lubricating oil, thus improving the efficiency of lubricating oil discharge via the inclined surface 6.

[0039] like Figure 2 As shown, in a cross-section cut along the axis of rotation 11, the inclination angle of the inclined plane 6 relative to the imaginary surface of the extended flat surface 43A is defined as θ. In several embodiments, the inclined plane 6 is configured such that the inclination angle θ increases as it moves from the two ends 61, 62 within the circumferential range CR toward a vertically downward position P1. In this case, lubricating oil guided from the sealing gap 20 to the inclined plane 6 can flow toward the vertically downward position P1, thereby allowing the lubricating oil to accumulate near the vertically downward position P1 of the inclined plane 6.

[0040] like Figure 2 As shown, in a cross-section taken along the axis of rotation 11, the length from the upper edge (side edge 42A) to the lower edge 44 of the inclined surface 6 is defined as the inclined surface length L. In several embodiments, the inclined surface 6 is configured such that the inclined surface length L increases as it moves from the two ends 61, 62 within the circumferential range CR toward the vertically downward position P1. In this case, lubricating oil guided from the sealing gap 20 to the inclined surface 6 can flow toward the vertically downward position P1, thereby allowing the lubricating oil to accumulate near the vertically downward position P1 of the inclined surface 6.

[0041] If the circumferential range CR of the inclined surface 6 is set too small, the effect of discharging lubricating oil from the sealing gap 20 through the inclined surface 6 will be reduced. Furthermore, if the circumferential range CR of the inclined surface 6 is set too large, excess inclined surface 6 will be formed in the circumferential range CR where lubricating oil falls due to gravity without passing through the inclined surface 6.

[0042] The circumferential range CR of the aforementioned inclined surface 6 is preferably set to a range of 60° or more and 120° or less. In this case, by setting the circumferential range CR of the inclined surface 6 to a range of 60° or more and 120° or less, compared with setting the circumferential range CR of the inclined surface 6 to a range of less than 60°, the effect of discharging lubricating oil from the sealing gap 20 via the inclined surface 6 can be improved. Furthermore, by setting the circumferential range CR of the inclined surface 6 to a range of 60° or more and 120° or less, compared with setting the circumferential range CR of the inclined surface 6 to a range of more than 120°, the formation of excess inclined surface 6 can be suppressed, thereby shortening the formation process of the inclined surface 6.

[0043] The circumferential range CR of the aforementioned inclined surface 6 is further preferably set to a range of 85° or more and 95° or less. In this case, by setting the circumferential range CR of the inclined surface 6 to a range of 85° or more and 95° or less, it is possible to suppress the reduction in the effect of discharging lubricating oil from the sealing gap 20 via the inclined surface 6, and it is possible to effectively suppress the formation of excess inclined surface 6.

[0044] In several implementation methods, such as Figure 2 As shown, at position P1, which is vertically below the axis LA of the rotation axis 11, the edge 42 (sloping edge 42A) on the second space 22 side of the stationary side inner peripheral surface 41 is located closer to the first space 21 side than the edge 32 on the second space 22 side of the rotational side outer peripheral surface 31.

[0045] Based on the above structure, the lubricating oil flowing down along the rotating side end face 33 is difficult to enter the sealing gap 20, thus it can suppress the flow of lubricating oil into the sealing gap 20, and further suppress the accumulation of lubricating oil in the lower part of the sealing gap 20.

[0046] Figure 5 It is a schematic cross-sectional view showing a section taken along the axis of the sealing structure of a turbocharger according to one embodiment. Figure 5 The text is a jumbled collection of characters and phrases, seemingly from different sources and lacking coherent sentences. A direct translation wouldn't be meaningful. Figure 1 The area enclosed by a double-dotted line. In several implementations, such as Figure 5As shown, the stationary end face 43 includes the inclined surface 6 and a flat surface 43B disposed in the area other than the area where the inclined surface 6 is formed. The flat surface 43B is continuous with the lower edge 44 of the inclined surface 6 and extends radially outward from the edge 42 on the second space 22 side of the stationary inner peripheral surface 41 along the rotation axis 11. At a position lower than the axis LA of the rotation axis 11, the flat surface 43B is located closer to the first space 21 side than the edge 32 on the second space 22 side of the rotation outer peripheral surface 31. In this case, the shape is formed such that lubricating oil flowing down along the rotation end face 33 is difficult to enter the sealing gap 20, thus suppressing the flow of lubricating oil into the sealing gap 20, and further suppressing the accumulation of lubricating oil in the lower part of the sealing gap 20.

[0047] In this specification, expressions such as "in a certain direction," "along a certain direction," "parallel," "orthogonal," "center," "concentric," or "coaxial," which indicate relative or absolute configuration, not only refer to such configuration in a strict sense, but also to the state of relative displacement by angle or distance with tolerance or to the extent that the same function can be obtained.

[0048] For example, expressions such as "same," "equal," and "homogeneous" that indicate the same state not only mean the same state in a strict sense, but also indicate the state with differences in tolerance or degree of attainment of the same function.

[0049] Furthermore, in this specification, the description of shapes such as quadrilaterals or cylinders refers not only to shapes such as quadrilaterals or cylinders in a strict geometric sense, but also to shapes such as concave or convex parts or chamfered parts within the range where the same effect can be obtained.

[0050] Furthermore, in this specification, expressions such as "possessing," "including," or "having" a constituent element are not exclusive expressions that exclude the existence of other constituent elements.

[0051] The present invention is not limited to the above-described embodiments, but also includes modifications to the above-described embodiments and appropriate combinations thereof.

[0052] For example, the contents described in the above-mentioned implementation methods are as follows.

[0053] 1) The sealing structure 2 of the turbocharger according to at least one embodiment of the present invention is the sealing structure of the turbocharger 1, which includes: The rotating component 3 includes at least the rotating shaft 11 of the turbocharger 1 and a rotating impeller 12 disposed at one end of the rotating shaft 11; The stationary component 4 includes at least a housing 14 for accommodating the rotating component 3; Bearing 13 rotatably supports the rotating shaft 11; and A sealing component 5 is disposed in a sealing gap 20, which is formed between the rotating component 3 and the stationary component 4, and connects a first space 21 for accommodating the rotating impeller 12 and a second space 22 for accommodating the bearing 13. The rotating component 3 includes at least a rotating outer peripheral surface 31 for defining the sealing gap 20. The stationary component 4 includes a stationary side inner peripheral surface 41 for defining the sealing gap 20 and a stationary side end surface 43 extending radially from the edge 42 on the second space 22 side of the stationary side inner peripheral surface 41 along the rotation axis 11. The stationary end face 43 includes an inclined surface 6, which is disposed within a predetermined circumferential range CR that is lower than the axis LA of the rotation axis 11, and is inclined toward the second space 22 side of the axis of the rotation axis 11 as it moves downward from the edge 42 of the second space 22 side of the stationary inner circumferential surface 41.

[0054] According to the structure described in 1), the inclined surface 6, located within a predetermined circumferential range CR below the axis LA of the rotating shaft 11 on the stationary side end face 43, allows lubricating oil to be discharged from the lower part of the sealing gap 20, thus preventing lubricating oil from accumulating in the lower part of the sealing gap 20. The sealing structure 2 of the turbocharger described in 1) prevents lubricating oil from stagnating in the lower part of the sealing gap 20, thereby preventing leakage of lubricating oil from the sealing member 5 located in the sealing gap 20 to the first space 21 side (the side where the rotating impeller 12 is located).

[0055] 2) In several embodiments, in the sealing structure 2 of the turbocharger described in 1) above, The inclined surface 6 is formed in such a manner that it includes a position P1 that is vertically below the axis LA relative to the rotation axis 11.

[0056] According to the structure in 2) above, by forming the inclined surface 6 with a position P1 that is vertically below the axis LA of the rotation shaft 11, lubricating oil can be directly discharged from the portion of the sealing gap 20 where lubricating oil accumulates, that is, the lower region including the position P1 that is vertically below the axis LA of the rotation shaft 11 of the sealing gap 20, to the inclined surface 6. Therefore, compared with the inclined surface 6 that does not include the vertically below position P1, the inclined surface 6 including the above-mentioned vertically below position P1 can effectively discharge lubricating oil from the lower part of the sealing gap 20 to the inclined surface 6.

[0057] 3) In several embodiments, in the sealing structure 2 of the turbocharger described in 2) above, The inclined plane 6 slopes circumferentially from both ends 61 and 62 within the circumferential range CR toward the vertically downward position P1.

[0058] According to the structure described in 3) above, by providing a circumferential inclination on the inclined surface 6 from both ends 61 and 62 within the circumferential range CR toward the vertically downward position P1, the lubricating oil guided from the sealing gap 20 to the inclined surface 6 can flow toward the vertically downward position P1. Thus, the flow of lubricating oil formed on the inclined surface 6 causes the lubricating oil to accumulate, thereby promoting movement along the inclination of the inclined surface 6 caused by the weight of the lubricating oil, thus improving the efficiency of lubricating oil discharge via the inclined surface 6.

[0059] 4) In several embodiments, in the sealing structure 7 of the turbocharger described in any one of 1) to 3) above, The circumferential range CR of the inclined plane 6 is set to be above 60° and below 120°.

[0060] Assuming that the circumferential range CR of the inclined surface 6 is too small, the effect of discharging lubricating oil through the sealing gap 20 via the inclined surface 6 will be reduced. Furthermore, assuming that the circumferential range CR of the inclined surface 6 is too large, excess inclined surface 6 will form within the circumferential range CR where lubricating oil falls due to gravity without passing through the inclined surface 6. According to the structure described in 4), by setting the circumferential range CR of the inclined surface 6 to a range of 60° or more and 120° or less, compared to setting the circumferential range CR of the inclined surface 6 to less than 60°, the effect of discharging lubricating oil through the sealing gap 20 via the inclined surface 6 can be improved. Furthermore, by setting the circumferential range CR of the inclined surface 6 to a range of 60° or more and 120° or less, compared to setting the circumferential range CR of the inclined surface 6 to a range exceeding 120°, the formation of excess inclined surface 6 can be suppressed, thereby shortening the formation process of the inclined surface 6.

[0061] 5) In several embodiments, in the sealing structure 2 of the turbocharger described in 4) above, The circumferential range CR of the inclined plane 6 is set to be above 85° and below 95°.

[0062] According to the structure in 5) above, by setting the circumferential range CR of the inclined surface 6 to a range of 85° or more and 95° or less, it is possible to suppress the reduction of the effect of discharging lubricating oil from the sealing gap 20 through the inclined surface 6, and to effectively suppress the formation of excess inclined surface 6.

[0063] 6) In several embodiments, in the sealing structure 2 of the turbocharger described in any one of 1) to 5) above, The rotating component 3 also includes a rotating end face 33 extending radially along the rotation axis 11 from the edge 32 on the second space 22 side of the rotating outer peripheral surface 31. At a position P1 perpendicularly below the axis LA relative to the rotation axis 11, the edge 42 on the second space 22 side of the stationary side inner peripheral surface 41 is located closer to the first space 21 side than the edge 32 on the second space 22 side of the rotational side outer peripheral surface 31.

[0064] According to the structure described in 6), at a position P1 vertically below the axis LA of the rotation shaft 11, the edge 42 (i.e., the upper edge of the inclined surface 6) on the inner peripheral surface 41 of the stationary side is located closer to the first space 21 side than the edge 32 on the outer peripheral surface 31 of the rotation side. In this case, the shape is formed such that lubricating oil flowing down along the end face 33 of the rotation side is difficult to enter the sealing gap 20, thus suppressing the flow of lubricating oil into the sealing gap 20, and further suppressing the accumulation of lubricating oil in the lower part of the sealing gap 20.

[0065] Symbol Explanation 1-Turbocharger; 2, 2A, 2B-Sealing structure; 3-Rotating component; 4-Stationary component; 5-Sealing component; 6-Inclined surface; 11-Rotating shaft; 12-Rotating impeller; 12A-Turbine impeller; 12B-Compressor impeller; 13-Bearing; 14-Housing; 15-Sleeve; 20, 20A, 20B-Sealing gap; 20C-Lower region; 21, 21A, 21B-First space; 22-Second space; 23-Lubricating oil inlet; 24 - Lubricating oil supply path, 25- Lubricating oil outlet, 31, 31A, 31B- Rotating side outer peripheral surface, 32- Edge, 33- Rotating side end face, 41, 41A, 41B- Stationary side inner peripheral surface, 42- Edge, 42A- Inclined side edge, 42B- Flat side edge, 43- Stationary side end face, 43A, 43B- Flat surface, 44- Lower edge, 61, 62- End, CR- Circumferential range, LA- Axis, P1- Vertically downward position.

Claims

1. A sealing structure of a turbocharger, comprising: a rotating member including at least a rotating shaft of the turbocharger and a rotating impeller provided on one end side of the rotating shaft; a stationary member including at least a casing for accommodating the rotating member; a bearing rotatably supporting the rotating shaft; and a sealing member provided in a sealing gap formed between the rotating member and the stationary member and communicating a first space for accommodating the rotating impeller and a second space for accommodating the bearing, wherein the rotating member includes at least a rotating-side outer circumferential surface for defining the sealing gap, wherein the stationary member includes a stationary-side inner circumferential surface for defining the sealing gap and a stationary-side end surface extending in a radial direction of the rotating shaft from an edge on the second space side of the stationary-side inner circumferential surface, and wherein the stationary-side end surface includes a slope provided in a prescribed circumferential range below an axis line of the rotating shaft and inclined toward the second space side in the axis line direction of the rotating shaft as it goes downward from the edge on the second space side of the stationary-side inner circumferential surface.

2. The sealing structure of the turbocharger according to claim 1, wherein the slope is formed in a manner including a position vertically below the axis line of the rotating shaft.

3. The sealing structure of the turbocharger according to claim 2, wherein the slope is inclined in a circumferential direction from both ends in the circumferential range toward the position vertically below.

4. The sealing structure of the turbocharger according to any one of claims 1 to 3, wherein a circumferential range of the slope is set to a range of 60° or more and 120° or less.

5. The sealing structure of the turbocharger according to claim 4, wherein the circumferential range of the slope is set to a range of 85° or more and 95° or less.

6. The sealing structure of the turbocharger according to any one of claims 1 to 3, wherein the rotating member further includes a rotating-side end surface extending in a radial direction of the rotating shaft from an edge on the second space side of the rotating-side outer circumferential surface, and wherein the edge on the second space side of the stationary-side inner circumferential surface is located more on the first space side than the edge on the second space side of the rotating-side outer circumferential surface at a position vertically below the axis line of the rotating shaft. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​

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