Turbocharger seal structure

Abstract

To provide a seal structure of a supercharger which can suppress the leakage of a lubricant.SOLUTION: A seal structure of a supercharger comprises: a rotating member including a rotating shaft of the supercharger and a rotating wheel provided at one end side of the rotating shaft; a stationary member including a housing for accommodating the rotating member; a bearing for rotatably supporting the rotating shaft; and a seal member formed between the rotating member and the stationary member, and provided in a seal clearance which makes a first space in which the rotating wheel is accommodated and a second space in which the bearing is accommodated communicate with each other. The stationary member includes a stationary-side internal peripheral face for defining the seal clearance, and a stationary-side end face extending in a radial direction of the rotating shaft from an edge of the second space side at the stationary-side internal peripheral face. The stationary end face includes a slope formed in a range in a prescribed peripheral direction at a lower side lower than an axial line of the rotating shaft, and inclined to the second space side in an axial line direction of the rotating shaft as progressing downward from the edge of the second space side of the stationary internal peripheral face.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to a seal structure for a turbocharger. [Background technology]

[0002] A turbocharger includes a rotor (rotating body) including a rotating shaft, a turbine impeller attached to one side of the rotating shaft, and a compressor impeller attached to the other side of the rotating shaft; bearings that rotatably support the rotating shaft between the turbine impeller and the compressor impeller; and a casing (stationary body) that houses the rotor and the bearings. Because the bearings of a turbocharger support the rotating shaft, which rotates at high speed, they are prone to become hot, and insufficient lubrication can lead to seizure. For this reason, the bearings are lubricated and cooled by supplying lubricating oil to the bearings. Some turbochargers include a seal ring that seals between the outer surface of a rotating body such as a rotor and the inner surface of a stationary body such as a casing to prevent leakage of lubricating oil supplied to the bearings to the compressor side or turbine side (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-232124 Summary of the Invention [Problem to be solved by the invention]

[0004] In a turbocharger equipped with a sealing mechanism using a seal ring, there is a risk of lubricating oil leakage. Specifically, lubricating oil may accumulate in the space between the outer surface of the rotating body to which the seal ring is attached and the inner surface of the stationary body, and the lubricating oil accumulated in the space may leak into the space on the opposite side of the seal ring.

[0005] In view of the above circumstances, at least one embodiment of the present invention has an object to provide a seal structure for a turbocharger that can suppress leakage of lubricating oil. [Means for solving the problem]

[0006] A seal structure for a turbocharger according to at least one embodiment of the present invention comprises: A seal structure for a turbocharger, a rotating member including at least a rotating shaft of the turbocharger and a rotating wheel provided on one end side of the rotating shaft; a stationary member including at least a housing that accommodates the rotating member; a bearing that rotatably supports the rotary shaft; a seal gap formed between the rotating member and the stationary member, the seal gap communicating a first space in which the rotating wheel is accommodated and a second space in which the bearing is accommodated; and a seal member provided in the seal gap, the rotating member includes at least a rotating outer peripheral surface that defines the seal gap, the stationary member includes a stationary-side inner circumferential surface that defines the seal gap, and a stationary-side end surface that extends from an edge of the stationary-side inner circumferential surface on the second space side along a radial direction of the rotation shaft, The stationary side end face includes a slope provided in a predetermined circumferential range below the axis of the rotating shaft, and includes a slope that inclines toward the second space in the axial direction of the rotating shaft as it extends downward from the edge of the stationary side inner surface on the second space side. [Effects of the Invention]

[0007] According to at least one embodiment of the present invention, there is provided a seal structure for a turbocharger that can suppress leakage of lubricating oil. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a schematic cross-sectional view showing a cross section along an axis of a supercharger including a seal structure for a supercharger according to one embodiment. [Figure 2]1 is a schematic cross-sectional view showing a cross section along an axis of a seal structure for a supercharger according to one embodiment. [Figure 3] 3 is a schematic view showing a state in which the seal structure of the turbocharger according to one embodiment is viewed from the second space side. FIG. [Figure 4] FIG. 1 is a schematic diagram illustrating a state in which the vicinity of a slope in a seal structure for a turbocharger according to one embodiment is viewed from above. [Figure 5] 1 is a schematic cross-sectional view showing a cross section along an axis of a seal structure for a supercharger according to one embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] 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 components described as embodiments or shown in the drawings are merely illustrative examples and are not intended to limit the scope of the present invention.

[0010] (Turbocharger) Fig. 1 is a schematic cross-sectional view showing a cross section along the axis of a turbocharger including a seal structure for a turbocharger according to one embodiment. As shown in Fig. 1, the turbocharger 1 includes a rotating shaft 11, a turbine wheel 12A provided on one end of the rotating shaft 11, a compressor wheel 12B provided on the other end of the rotating shaft 11, a bearing 13 that rotatably supports the rotating shaft 11, and a housing 14 that accommodates the rotating shaft 11, the turbine wheel 12A, the compressor wheel 12B, and the bearing 13.

[0011] The bearing 13 is supported by a housing 14. The rotating shaft 11 is supported by the bearing 13 between the turbine wheel 12A and the compressor wheel 12B, and is thereby rotatable about the axis line LA of the rotating shaft 11.

[0012] Hereinafter, the direction in which the axis line LA of the rotating shaft 11 extends is defined as the axial direction of the rotating shaft 11 (turbocharger 1), and the direction perpendicular to the axis line 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 where the turbine wheel 12A is located relative to the compressor wheel 12B is defined as the turbine side, and the side where the compressor wheel 12B is located relative to the turbine wheel 12A is defined as the compressor side.

[0013] The turbine wheel 12A is configured to rotate by the energy of exhaust gas discharged from the engine and guided to the turbine wheel 12A. The compressor wheel 12B rotates together with the rotary shaft 11 in conjunction with the rotation of the turbine wheel 12A. The turbocharger 1 is configured to compress gas (e.g., air) guided to the compressor wheel 12B by the rotation of the compressor wheel 12B, increase the density of the gas, and send the gas to a supply destination (e.g., the engine).

[0014] (Turbocharger seal structure) Fig. 2 is a schematic cross-sectional view showing a cross section along the axis of a seal structure for a turbocharger according to one embodiment. Fig. 2 shows an area surrounded by a two-dot chain line in Fig. 1. Fig. 3 is a schematic view showing the seal structure for a turbocharger according to one embodiment as viewed from the second space side. Fig. 4 is a schematic view showing the vicinity of a slope in the seal structure for a turbocharger according to one embodiment as viewed from above. A seal structure 2 for a turbocharger according to some embodiments is a seal structure provided in a turbocharger 1 to suppress leakage of lubricating oil in the turbocharger 1. As shown in Figs. 1 and 2, the seal structure 2 for a turbocharger includes a rotating member 3, a stationary member 4 that houses the rotating member 3, a seal member 5 provided in a seal gap 20 formed between the rotating member 3 and the stationary member 4, and the bearing 13 described above.

[0015] (Rotating parts, stationary parts) The rotating member 3 is configured to rotate when the turbocharger 1 is driven. The rotating member 3 includes at least a rotating shaft 11 and a rotating wheel 12 provided on one end side of the rotating shaft 11. The stationary member 4 is configured to remain stationary (do not rotate) even when the rotating member 3 rotates when the turbocharger 1 is driven. The stationary member 4 includes at least a housing 14.

[0016] The stationary member 4 (housing 14) accommodates the rotating member 3 and the bearing 13. Inside the stationary member 4 (housing 14), the above-mentioned seal gap 20, a first space 21 in which the rotating wheel 12 is accommodated, and a second space 22 in which the bearing 13 is accommodated are formed. The seal gap 20 is provided between the first space 21 and the second space 22 in the axial direction of the rotating shaft 11, and connects the first space 21 and the second space 22.

[0017] The rotating member 3 has a rotating-side outer peripheral surface 31 that defines the seal gap 20. The stationary member 4 has a stationary-side inner peripheral surface 41 that defines the seal gap 20. The stationary-side inner peripheral surface 41 is provided further outward in the radial direction of the rotating shaft 11 than the rotating-side outer peripheral surface 31, and faces the rotating-side outer peripheral surface 31 across the annular seal gap 20.

[0018] As shown in Fig. 2, the stationary member 4 has a stationary-side end face 43 that extends from an edge 42 of the stationary-side inner peripheral surface 41 on the second space 22 side toward the outside in the radial direction of the rotating shaft 11. The rotating member 3 may have a rotating-side end face 33 that extends from an edge 32 of the rotating-side outer peripheral surface 31 on the second space 22 side toward the inside in the radial direction of the rotating shaft 11.

[0019] (Sealing material) The seal member 5 is configured to seal between the stationary-side inner peripheral surface 41 and the rotating-side outer peripheral surface 31. In the illustrated embodiment, as shown in Fig. 2, the seal member (seal ring) 5 is disposed in a compressed state between the stationary-side inner peripheral surface 41 and the rotating-side outer peripheral surface 31, with its outer peripheral surface abutting against the stationary-side inner peripheral surface 41 and its inner peripheral surface abutting against the rotating-side outer peripheral surface 31. As shown in Figs. 1 and 2, at least one of the stationary-side inner peripheral surface 41 and the rotating-side outer peripheral surface 31 may be provided with an annular groove extending along the circumferential direction of the rotating shaft 11, into which a portion of the seal member 5 is fitted.

[0020] (lubricating oil system) The turbocharger 1 is configured so that lubricating oil flows into the bearing 13 and the second space 22 in which the bearing 13 is housed. In the embodiment shown in Fig. 1, the housing 14 is formed with a lubricating oil inlet 23 for introducing the lubricating oil into the interior thereof, a lubricating oil supply passage 24 for guiding the lubricating oil from the lubricating oil inlet 23 to the bearing 13, and a lubricating oil outlet 25 for discharging the lubricating oil to the outside of the housing 14. The lubricating oil supply passage 24 is formed with a flow path defined by the inner wall surface of the housing 14, which connects the lubricating oil inlet 23 and the second space 22. The lubricating oil outlet 25 is provided below the second space 22 and communicates with a lower part of the second space 22.

[0021] The lubricating oil introduced into the housing 14 through the lubricating oil inlet 23 is guided to the bearing 13 through the lubricating oil supply passage 24. Most of the lubricating oil guided to the bearing 13 flows downward in the second space 22 and is discharged to the outside of the housing 14 through the lubricating oil outlet 25. Some of the lubricating oil guided to the bearing 13 may flow into the seal gap 20.

[0022] A seal structure 2 of a turbocharger 1 according to some embodiments includes the above-described rotating member 3, the above-described stationary member 4, the above-described bearing 13, and the above-described seal member 5 provided in the seal gap 20. The stationary member 4 includes the above-described stationary-side inner circumferential surface 41 and the above-described stationary-side end face 43. As shown in FIGS. 2 and 3 , the stationary-side end face 43 includes a slope 6 provided in a predetermined circumferential range CR below the axis LA of the rotating shaft 11. The slope 6 is inclined toward the second space 22 in the axial direction of the rotating shaft 11 (the direction in which the axis LA of the rotating shaft 11 extends) as it extends downward from an edge 42 of the stationary-side inner circumferential surface 41 on the second space 22 side.

[0023] As shown in FIGS. 2 to 4 , the stationary-side end face 43 further includes a flat surface 43A provided in a region other than the region where the slope 6 is formed. The flat surface 43A extends radially outward from an edge 42 of the stationary-side inner circumferential surface 41 on the second space 22 side along the radial direction of the rotating shaft 11. As shown in FIG. 4 , of the edge 42 of the stationary-side inner circumferential surface 41 on the second space 22 side, a slope-side edge 42A (an upper edge of the slope 6) that is continuous with the slope 6 has a concave curved shape that is recessed toward the first space 21 in the axial direction of the rotating shaft 11 more than a flat-side edge 42B (an inner circumferential edge of the flat surface 43A that is continuous with the stationary-side inner circumferential surface 41) that is continuous with the flat surface 43A. The slope 6 has a lower edge 44 that is continuous with the flat surface 43A. As shown in FIG. 3 , the lower edge 44 has a convex curved shape that faces downward when viewed from the second space 22 side in the axial direction of the rotating shaft 11.

[0024] The lubricating oil that has flowed into the seal gap 20 accumulates in the lower part of the seal gap 20. At least a part of the lubricating oil that accumulates in the lower part of the seal gap 20 flows down along the slope 6 and is discharged into the second space 22.

[0025] According to the above configuration, the slope 6 provided in the predetermined circumferential range CR below the axis LA of the rotating shaft 11 on the stationary side end face 43 allows the lubricating oil to be discharged from the lower part of the seal gap 20, thereby preventing the lubricating oil from accumulating in the lower part of the seal gap 20. By preventing the lubricating oil from accumulating in the lower part of the seal gap 20, the seal structure 2 for the turbocharger can prevent the lubricating oil from leaking beyond the seal member 5 provided in the seal gap 20 to the first space 21 side (the side where the rotating wheel 12 is located).

[0026] In some embodiments, as shown in Fig. 1, the seal structure 2A(2) of the turbocharger is intended to suppress leakage of lubricating oil from the second space 22 to the first space 21A(21) in which the turbine wheel 12A is housed. The rotating wheel 12 of the seal structure 2A of the turbocharger is made up of the turbine wheel 12A described above. As shown in Fig. 1, the first space 21A, which is the space in which the turbine wheel 12A is housed, and the seal gap 20A(20) are provided closer to the turbine in the axial direction of the rotating shaft 11 than the second space 22 in which the bearing 13 is housed.

[0027] The rotating-side outer peripheral surface 31A (31) may be, for example, the outer peripheral surface of a boss portion protruding from the back surface of the turbine wheel 12A as shown in Fig. 1. The stationary-side inner peripheral surface 41A (41) may be the inner wall surface of the housing 14 facing the outer peripheral surface of the boss portion of the turbine wheel 12A across the seal gap 20A.

[0028] In some embodiments, as shown in Fig. 1, the seal structure 2B(2) of the turbocharger is intended to suppress leakage of lubricating oil from the second space 22 to the first space 21B(21) in which the compressor wheel 12B is housed. The rotating wheel 12 of the seal structure 2B of the turbocharger is made up of the compressor wheel 12B described above. As shown in Fig. 1, the first space 21B(21), which is the space in which the compressor wheel 12B is housed, and the seal gap 20B(20) are provided on the compressor side in the axial direction of the rotating shaft 11 relative to the second space 22 in which the bearing 13 is housed.

[0029] The rotating-side outer peripheral surface 31B (31) may be, for example, the outer peripheral surface of an annular sleeve 15 included in the turbocharger 1 as shown in FIG. 1. The sleeve 15 is attached to the rotating shaft 11 between the compressor wheel 12B (rotating wheel 12) and the bearing 13 in the axial direction of the rotating shaft 11 so as to cover the outer periphery of the rotating shaft 11. The rotating member 3 may further include the sleeve 15. The stationary-side inner peripheral surface 41B (41) may be an inner wall surface of the housing 14 that faces the outer peripheral surface of the sleeve 15 across the seal gap 20B. Furthermore, the rotating-side outer peripheral surface 31 may be the outer peripheral surface of the rotating shaft 11.

[0030] The turbocharger 1 may include both the turbocharger seal structures 2A and 2B. That is, the end face of the stationary-side inner circumferential surface 41A continuing to the compressor side and the end face of the stationary-side inner circumferential surface 41B continuing to the turbine side may each be the stationary-side end face 43 including the slope 6 described above.

[0031] 3, the slope 6 is formed to include a position P1 vertically below the axis LA of the rotating shaft 11. In this case, one end 61 of the circumferential range CR of the slope 6 is provided on one side in the horizontal direction with respect to the axis LA of the rotating shaft 11. The other end 62 of the circumferential range CR of the slope 6 is provided on the opposite side (the other side) from the one end 61 in the horizontal direction with respect to the axis LA of the rotating shaft 11.

[0032] According to the above configuration, by forming the slope 6 so as to include a position P1 vertically below the axis LA of the rotating shaft 11, the lubricating oil can be directly discharged from a lower region 20C (see FIG. 3 ) including the position P1 vertically below the axis LA of the rotating shaft 11 of the seal gap 20, which is the portion where the lubricating oil accumulates in the seal gap 20, to the slope 6. Therefore, the slope 6 including the vertically below position P1 can more effectively discharge the lubricating oil from the lower part of the seal gap 20 to the slope 6 than a slope 6 that does not include the vertically below position P1.

[0033] In some embodiments, as shown in FIG. 3, the slope 6 inclines in the circumferential direction from both ends 61, 62 in the circumferential range CR toward the vertically downward position P1.

[0034] According to the above configuration, by providing the slope 6 with a circumferential inclination from both ends 61, 62 in the circumferential range CR toward the vertically downward position P1, the lubricating oil guided from the seal gap 20 to the slope 6 can flow toward the vertically downward position P1. This causes the lubricating oil to collect near the vertically downward position P1 of the slope 6, and promotes the movement of the lubricating oil along the inclination of the slope 6 due to its own weight, thereby improving the efficiency with which the lubricating oil is discharged via the slope 6.

[0035] 2, in a cross section taken along the axis of the rotating shaft 11, the inclination angle of the slope 6 with respect to an imaginary plane formed by extending the flat surface 43A is defined as θ. In some embodiments, the slope 6 is configured so that the inclination angle θ increases from both ends 61, 62 in the circumferential range CR toward a position P1 vertically below. In this case, the lubricating oil guided from the seal gap 20 to the slope 6 can flow toward the position P1 vertically below, and the lubricating oil can be collected near the position P1 vertically below the slope 6.

[0036] 2, in a cross section taken along the axis of the rotating shaft 11, the length from the upper edge (slope side edge 42A) of the slope 6 to the lower edge 44 is defined as the slope length L. In some embodiments, the above-described slope 6 is configured so that the slope length L increases from both ends 61, 62 in the circumferential range CR toward a position P1 vertically below. In this case, the lubricating oil guided from the seal gap 20 to the slope 6 can flow toward the position P1 vertically below, and the lubricating oil can be collected near the position P1 vertically below the slope 6.

[0037] If the circumferential range CR of the slope 6 is made too small, the effect of discharging the lubricating oil from the seal gap 20 via the slope 6 will be reduced. On the other hand, if the circumferential range CR of the slope 6 is made too large, an excess slope 6 will be formed in the circumferential range CR, causing the lubricating oil to fall by gravity without passing through the slope 6.

[0038] The circumferential range CR of the slope 6 described above is preferably set in the range of 60° to 120°. In this case, by setting the circumferential range CR of the slope 6 in the range of 60° to 120°, the effect of discharging lubricating oil from the seal gap 20 via the slope 6 can be improved compared to when the circumferential range CR of the slope 6 is set to less than 60°. Furthermore, by setting the circumferential range CR of the slope 6 in the range of 60° to 120°, the formation of an excess slope 6 can be suppressed compared to when the circumferential range CR of the slope 6 is set to more than 120°, and the work required to form the slope 6 can be shortened.

[0039] It is more preferable that the circumferential range CR of the slope 6 described above is set to a range of 85° or more and 95° or less. In this case, by setting the circumferential range CR of the slope 6 to a range of 85° or more and 95° or less, it is possible to effectively prevent the formation of an excess slope 6 while suppressing a decrease in the effect of discharging lubricating oil from the seal gap 20 via the slope 6.

[0040] In some embodiments, as shown in Figure 2, at a position P1 vertically below the axis LA of the rotating shaft 11, the edge 42 (slope side edge 42A) on the stationary side inner surface 41 facing the second space 22 is located closer to the first space 21 than the edge 32 on the rotating side outer surface 31 facing the second space 22.

[0041] According to the above configuration, the shape of the seal gap 20 makes it difficult for the lubricating oil that flows down the rotating side end face 33 to enter the seal gap 20, which prevents the lubricating oil from flowing into the seal gap 20 and ultimately prevents the lubricating oil from accumulating at the bottom of the seal gap 20.

[0042] 5 is a schematic cross-sectional view showing a cross section along the axis of a seal structure for a turbocharger according to one embodiment. FIG. 5 illustrates the area surrounded by the two-dot chain line in FIG. 1. In some embodiments, as shown in FIG. 5, the stationary-side end surface 43 includes the slope 6 and a flat surface 43B provided in an area other than the area where the slope 6 is formed. The flat surface 43B is continuous with a lower edge 44 of the slope 6 and extends radially outward from an edge 42 of the stationary-side inner circumferential surface 41 on the second space 22 side along the radial direction of the rotating shaft 11. Below the axis LA of the rotating shaft 11, the flat surface 43B is located closer to the first space 21 than the edge 32 of the rotating-side outer circumferential surface 31 on the second space 22 side. In this case, the shape of the seal gap 20 makes it difficult for the lubricating oil that flows down the rotating side end face 33 to enter the seal gap 20, so the inflow of the lubricating oil into the seal gap 20 can be suppressed, and the accumulation of the lubricating oil at the bottom of the seal gap 20 can be suppressed.

[0043] In this specification, expressions expressing relative or absolute arrangement such as "in a certain direction," "along a certain direction," "parallel," "orthogonal," "center," "concentric," or "coaxial" not only express such an arrangement strictly, but also express a state in which there is a relative displacement with a tolerance or an angle or distance to the extent that the same function is obtained. For example, expressions such as "identical," "equal," and "homogeneous" that indicate that something is in an equal state not only indicate a state of strict equality, but also indicate a state in which there is a tolerance or a difference to the extent that the same function is obtained. Furthermore, in this specification, expressions representing shapes such as a rectangular shape or a cylindrical shape not only represent rectangular shapes or cylindrical shapes in the strict geometric sense, but also represent shapes including uneven portions, chamfered portions, etc., to the extent that the same effect can be obtained. Furthermore, in this specification, the expressions "comprise," "include," or "have" a component are not exclusive expressions that exclude the presence of other components.

[0044] The present disclosure is not limited to the above-described embodiments, but also includes modifications to the above-described embodiments and appropriate combinations of these modifications.

[0045] The contents of the above-described embodiments can be understood, for example, as follows.

[0046] 1) A seal structure (2) for a turbocharger according to at least one embodiment of the present disclosure is A seal structure for a turbocharger (1), a rotating member (3) including at least a rotating shaft (11) of the turbocharger (1) and a rotating wheel (12) provided on one end side of the rotating shaft (11); a stationary member (4) including at least a housing (14) for accommodating the rotating member (3); a bearing (13) that rotatably supports the rotary shaft (11); a seal gap (20) formed between the rotating member (3) and the stationary member (4), the seal gap (20) communicating between a first space (21) in which the rotating wheel (12) is housed and a second space (22) in which the bearing (13) is housed; and a seal member (5) provided in the seal gap (20), The rotating member (3) includes at least a rotating outer peripheral surface (31) that defines the seal gap (20), the stationary member (4) includes a stationary-side inner circumferential surface (41) that defines the seal gap (20), and a stationary-side end surface (43) that extends from an edge (42) of the stationary-side inner circumferential surface (41) on the second space (22) side along the radial direction of the rotating shaft (11), The stationary side end face (43) includes a slope (6) provided in a predetermined circumferential range (CR) below the axis (LA) of the rotating shaft (11), and includes a slope (6) that inclines toward the second space (22) in the axial direction of the rotating shaft (11) as it extends downward from the edge (42) of the stationary side inner surface (41) on the second space (22) side.

[0047] According to the configuration of 1) above, the slope (6) provided in the predetermined circumferential range (CR) below the axis (LA) of the rotating shaft (11) on the stationary side end face (43) allows the lubricating oil to be discharged from the lower part of the seal gap (20), thereby making it possible to prevent the lubricating oil from accumulating in the lower part of the seal gap (20). The seal structure (2) for the turbocharger described in 1) above prevents the lubricating oil from accumulating in the lower part of the seal gap (20), thereby making it possible to prevent the lubricating oil from leaking beyond the seal member (5) provided in the seal gap (20) to the first space (21) side (the side where the rotating wheel 12 is located).

[0048] 2) In some embodiments, the seal structure (2) of the turbocharger described in 1) above, The slope (6) is formed so as to include a position (P1) vertically below the axis (LA) of the rotating shaft (11).

[0049] According to the above configuration 2), by forming the slope (6) so as to include the position (P1) vertically below the axis (LA) of the rotating shaft (11), the lubricating oil can be directly discharged from a lower region of the seal gap (20) including the position (P1) vertically below the axis (LA) of the rotating shaft (11), which is a portion where the lubricating oil accumulates in the seal gap (20), to the slope (6). Therefore, the slope (6) including the vertically below position (P1) can more effectively discharge the lubricating oil from the lower part of the seal gap (20) to the slope (6) than the slope (6) that does not include the vertically below position (P1).

[0050] 3) In some embodiments, the seal structure (2) of the turbocharger described in 2) above, The slope (6) is inclined in the circumferential direction from both ends (61, 62) of the circumferential range (CR) toward the vertically downward position (P1).

[0051] According to the configuration 3), the slope (6) is inclined in the circumferential direction from both ends (61, 62) in the circumferential range (CR) toward the vertically downward position (P1), thereby allowing the lubricating oil guided from the seal gap (20) to the slope (6) to flow toward the vertically downward position (P1). As a result, the flow of lubricating oil formed on the slope (6) collects the lubricating oil, and promotes the movement of the lubricating oil along the inclination of the slope (6) due to its own weight, thereby improving the efficiency of discharging the lubricating oil through the slope (6).

[0052] 4) In some embodiments, the seal structure (7) for a turbocharger according to any one of 1) to 3) above, The circumferential range (CR) of the slope (6) was set to a range of 60° to 120°.

[0053] If the circumferential range (CR) of the slope (6) is made too small, the effect of discharging the lubricating oil from the seal gap (20) via the slope (6) will be reduced. On the other hand, if the circumferential range (CR) of the slope (6) is made too large, an excess slope (6) will be formed in the circumferential range (CR) such that the lubricating oil will fall by gravity without passing through the slope (6). According to the configuration of 4) above, by setting the circumferential range (CR) of the slope (6) in the range of 60° to 120°, the effect of discharging the lubricating oil from the seal gap (20) via the slope (6) can be improved compared to when the circumferential range (CR) of the slope (6) is set to less than 60°. Furthermore, by setting the circumferential range (CR) of the slope (6) to a range of 60° or more and 120° or less, it is possible to prevent excess slopes (6) from being formed compared to when the circumferential range (CR) of the slope (6) is set to a range exceeding 120°, and the work of forming the slopes (6) can be shortened.

[0054] 5) In some embodiments, the seal structure (2) of the turbocharger described in 4) above, The circumferential range (CR) of the slope (6) is set to a range of 85° to 95°.

[0055] According to the configuration of 5) above, by setting the circumferential range (CR) of the slope (6) within a range of 85° or more and 95° or less, it is possible to effectively prevent the formation of an excess slope (6) while suppressing a decrease in the effect of discharging lubricating oil from the seal gap (20) via the slope (6).

[0056] 6) In some embodiments, the seal structure (2) for a turbocharger according to any one of 1) to 5) above, the rotating member (3) further includes a rotation-side end surface (33) extending from an edge (32) of the rotation-side outer peripheral surface (31) on the second space (22) side along the radial direction of the rotating shaft (11), At a position (P1) vertically below the axis (LA) of the rotating shaft (11), the edge (42) on the stationary side inner surface (41) facing the second space (22) is located closer to the first space (21) than the edge (32) on the rotating side outer surface (31) facing the second space (22).

[0057] According to the configuration of 6) above, at a position P1 vertically below the axis LA of the rotating shaft 11, the edge 42 of the stationary-side inner peripheral surface 41 on the second space 22 side, i.e., the upper edge of the slope 6, is located closer to the first space 21 than the edge 32 of the rotating-side outer peripheral surface 31 on the second space 22 side. In this case, the shape makes it difficult for the lubricating oil flowing down the rotating-side end face 33 to enter the seal gap 20, so that the inflow of the lubricating oil into the seal gap 20 can be suppressed, and as a result, the accumulation of the lubricating oil in the lower part of the seal gap 20 can be suppressed. [Explanation of symbols]

[0058] 1. Turbocharger 2, 2A, 2B seal structure 3 Rotating members 4 Stationary members 5 Sealing material 6. Slope 11 Rotation axis 12 spinning wheels 12A turbine wheel 12B compressor wheel 13 Bearings 14 Housing 15 sleeve 20, 20A, 20B Seal gap 20C lower area 21,21A,21B 1st space 22 Second space 23 Lubricating oil inlet 24 Lubricating oil supply path 25 Lubricating oil outlet 31, 31A, 31B Rotating side outer surface 32 En 33 Rotating side end face 41,41A,41B Stationary side inner surface 42 En 42A Slope side edge 42B Flat side edge Side edge 43 Stationary side end face 43A,43B Flat surface 44 Lower edge 61,62 edge CR Circumferential Range LA axis P1 Vertically downward position

Claims

1. A seal structure for a turbocharger, a rotating member including at least a rotating shaft of the turbocharger and a rotating wheel provided on one end side of the rotating shaft; a stationary member including at least a housing that accommodates the rotating member; a bearing that rotatably supports the rotary shaft; a seal gap formed between the rotating member and the stationary member, the seal gap communicating a first space in which the rotating wheel is accommodated and a second space in which the bearing is accommodated; and a seal member provided in the seal gap, the rotating member includes at least a rotating outer peripheral surface that defines the seal gap, the stationary member includes a stationary-side inner circumferential surface that defines the seal gap, and a stationary-side end surface that extends from a slope-side edge of the stationary-side inner circumferential surface that is on the second space side along a radial direction of the rotation shaft, In the axial direction of the rotating shaft, an axial position of the slope-side edge overlaps with an area where the rotating-side outer peripheral surface is present, the stationary-side end surface includes a slope provided in a predetermined circumferential range below the axis of the rotating shaft, the slope inclining toward the second space in the axial direction of the rotating shaft as it extends downward from the slope-side edge of the stationary-side inner circumferential surface on the second space side, Turbocharger seal structure.

2. A seal structure for a turbocharger, a rotating member including at least a rotating shaft of the turbocharger and a rotating wheel provided on one end side of the rotating shaft; a stationary member including at least a housing that accommodates the rotating member; a bearing that rotatably supports the rotary shaft; a seal gap formed between the rotating member and the stationary member, the seal gap communicating a first space in which the rotating wheel is accommodated and a second space in which the bearing is accommodated; and a seal member provided in the seal gap, the rotating member includes at least a rotating outer peripheral surface that defines the seal gap, the stationary member includes a stationary-side inner circumferential surface that defines the seal gap, and a stationary-side end surface that extends from a slope-side edge of the stationary-side inner circumferential surface that is on the second space side along a radial direction of the rotation shaft, the stationary-side end surface includes a slope that is provided in a predetermined circumferential range below the axis of the rotating shaft, and that slopes downward from the slope-side edge of the stationary-side inner circumferential surface on the second space side toward the second space in the axial direction of the rotating shaft, the stationary end surface further includes a flat surface provided outside the area where the slope is formed, A slope side edge of the stationary-side inner circumferential surface that is continuous with the slope has a concave curved shape that is recessed toward the first space side more than a flat surface side edge that is continuous with the flat surface. Turbocharger seal structure.

3. The slope is formed to include a position vertically below the axis of the rotation shaft. The seal structure for a turbocharger according to claim 1 or 2.

4. The slope inclines in the circumferential direction from both ends of the circumferential range toward the vertically downward position. The seal structure for a turbocharger according to claim 3.

5. The circumferential range of the slope is set to a range of 60° or more and 120° or less. The seal structure for a turbocharger according to claim 1 or 2.

6. The circumferential range of the slope is set to a range of 85° or more and 95° or less. The seal structure for a turbocharger according to claim 5.

7. the rotating member further includes a rotation-side end surface extending from an edge of the rotation-side outer peripheral surface on the second space side along a radial direction of the rotation shaft, At a position vertically below the axis of the rotating shaft, the slope-side edge of the stationary-side inner peripheral surface on the second space side is positioned closer to the first space than the edge of the rotating-side outer peripheral surface on the second space side. The seal structure for a turbocharger according to claim 1 or 2.

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