turbocharger

Abstract

Turbocharger (TC) with: a radial bearing support (50) which has a bearing hole (3b); a radial bearing (13) which is provided in the bearing hole (3b); a shaft (15) which is inserted into the radial bearing (13); a wheel (19) which is provided on the shaft (15); a thrust bearing (63) into which the shaft (15) is inserted, wherein the thrust bearing (63) is arranged between the radial bearing support (50) and the impeller (19); a support section (65) which is provided on the shaft (15) and is arranged between the radial bearing (13) and the thrust bearing (63); an oil chamber (80) which is formed below the radial bearing support (50) and the thrust bearing (63); an oil outlet (110) which is connected to the oil chamber (80) and is open to an outside; an oil drainage path (50d) formed in the radial bearing support (50), wherein one end of the oil drainage path (50d) in the radial bearing support (50) is open at least on one of a surface facing the shear bearing (63) and a surface facing the support section (65), wherein another end of the oil drainage path (50d) is open on a bottom surface of the radial bearing support (50), wherein an entire projection surface (S1) of the oil drainage path (50d), projected along a central axis (O) thereto to the oil outlet (110), is contained within the oil outlet (110); and an oil drainage space (120) which is provided between the thrust bearing (63) and the impeller (19) and is connected to the oil chamber (80).

Description

Technical area

[0001] The present invention relates to a turbocharger. State of the art

[0002] JP 5 807 436 B2 discloses a turbocharger comprising a radial bearing and a thrust bearing in a bearing housing. A shaft is inserted into the radial bearing and the thrust bearing. The radial bearing rotatably supports the shaft. The radial bearing absorbs the radial load from the shaft. The thrust bearing absorbs the axial load from the shaft.

[0003] The bearing housing has a lubricant path, an oil drainage path, an oil chamber, and an outlet. The lubricant path supplies lubricant to the radial and thrust bearings. The oil drainage path directs a portion of the lubricant after lubricating the radial and thrust bearings to the oil chamber. The outlet allows the lubricant in the oil chamber to drain out of the bearing housing.

[0004] DE 11 2019 006 976 T5 (state of the art according to Section 3 (2) of the Patent Act) relates to a turbocharger whose oil drainage bore is at least partially directed toward an outlet. DE 10 2014 217 053 A1, DE 11 2017 001 796 T5, and DE 3 531 313 C2 disclose further prior art. SummaryTechnical problem

[0005] In JP 5 807 436 B2, a wall surface forming the oil chamber of the bearing housing is located on an extension of the oil drainage path. The lubricant passing through the oil drainage path moves along the extension of the oil drainage path and encounters the wall surface forming the oil chamber. When the lubricant encounters the wall surface, the flow of the lubricant discharged from the outlet is disrupted. In such a case where the flow of the lubricant is disrupted, it is difficult for the lubricant in the oil chamber to be discharged from the outlet, and the lubricant is likely to remain in the oil chamber. If the lubricant is likely to remain, the lubricant may escape from the bearing housing to a turbine side or a compressor side.

[0006] The present invention aims and has the object of providing a turbocharger which can reduce leakage of lubricant. Solution to the problem

[0007] The above object is achieved by a turbocharger according to claim 1.

[0008] A further advantageous embodiment is disclosed in subclaim 2. Effects of the invention

[0009] According to the present invention, leakage of lubricant can be reduced. Brief description of the drawings Fig. 1 is a schematic sectional view of a turbocharger. Fig. 2 is a first extract of an area that is Fig. 1 is enclosed by dashed lines. Fig. 3 is a second extract of the area shown in Fig. 1 is enclosed by the dashed lines. Description of the embodiments

[0010] Embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Specific dimensions, materials, and numerical values ​​described in the embodiments are merely examples for better understanding and do not limit the present invention unless otherwise stated. In this description and the drawings, duplicate explanations for elements having substantially the same functions and configurations are omitted by assigning the same reference numerals. Furthermore, elements not directly related to the present invention are omitted from the figures.

[0011] Fig. 1 is a schematic sectional view of a turbocharger TC. The following is a direction shown in Fig. 1 is indicated by an arrow L, as a left side of the turbocharger TC. A direction that is Fig. 1 indicated by an arrow R is explained as a right side of the turbocharger TC. As shown in Fig. As shown in Figure 1, the turbocharger TC includes a turbocharger body 1. The turbocharger body 1 includes a bearing housing 3, a turbine housing 5, and a compressor housing 7. The turbine housing 5 is connected to the left side of the bearing housing 3 by a fastening mechanism 9. The compressor housing 7 is connected to the right side of the bearing housing 3 by fastening bolts 11.

[0012] A projection 3a is provided on an outer surface of the bearing housing 3. The projection 3a is provided on a side closer to the turbine housing 5. The projection 3a protrudes in a radial direction of the bearing housing 3. A projection 5a is provided on an outer surface of the turbine housing 5. The projection 5a is provided on a side closer to the bearing housing 3. The projection 5a protrudes in a radial direction of the turbine housing 5. The bearing housing 3 and the turbine housing 5 are fastened to each other by the fastening mechanism 9. The fastening mechanism 9 includes, for example, a G-type coupling. The fastening mechanism 9 clamps the projections 3a, 5a.

[0013] A bearing hole 3b is formed in the bearing housing 3. The bearing hole 3b passes through in the left / right direction of the turbocharger TC. A radial bearing 13 is arranged in the bearing hole 3b. Fig. 1, a semi-floating bearing is shown as an example of the radial bearing 13. However, the radial bearing 13 may be any other radial bearing, such as a fully floating bearing or a rolling bearing. A shaft 15 is fitted into the radial bearing 13. The radial bearing 13 rotatably supports the shaft 15. A turbine impeller 17 is provided at the left end of the shaft 15. The turbine impeller 17 is rotatably received in the turbine housing 5. A compressor impeller (runner) 19 is provided at the right end of the shaft 15. The compressor impeller 19 is rotatably received in the compressor housing 7.

[0014] An inlet 21 is formed in the compressor housing 7. The inlet 21 is open to the right side of the turbocharger TC. The inlet 21 is connected to an air cleaner (not shown). A diffuser flow path 23 is formed through opposing surfaces of the bearing housing 3 and the compressor housing 7. The diffuser flow path 23 pressurizes air. The diffuser flow path 23 is formed in a circular ring shape. The diffuser flow path 23 is connected to the inlet 21 through the compressor impeller 19 at an inner part in a radial direction of the shaft 15.

[0015] The compressor housing 7 is provided with a compressor scroll flow path 25. The compressor scroll flow path 25 is formed in a circular ring shape. The compressor scroll flow path 25 is located, for example, outside the diffuser flow path 23 in the radial direction of the shaft 15. The compressor scroll flow path 25 is connected to an engine intake (not shown) and the diffuser flow path 23. As the compressor impeller 19 rotates, air is drawn from the inlet 21 into the compressor housing 7. The intake air is pressurized and accelerated by the blades of the compressor impeller 19 as it travels. The pressurized and accelerated air is further pressurized in the diffuser flow path 23 and the compressor scroll flow path 25. The pressurized air is directed to the engine intake.

[0016] An outlet 27 is formed in the turbine housing 5. The outlet 27 is open to the left side of the turbocharger TC. The outlet 27 is connected to an exhaust gas purifier (not shown). A connecting path 29 and a turbine scroll flow path 31 are formed in the turbine housing 5. The turbine scroll flow path 31 is formed in a circular ring shape. The turbine scroll flow path 31 is located, for example, outside the connecting path 29 in the radial direction of the shaft 15. The turbine scroll flow path 31 is connected to a gas inlet (not shown). Exhaust gas discharged from an engine exhaust manifold (not shown) is guided to the gas inlet. The connecting path 29 connects the turbine scroll flow path 31 to the outlet 2 through the turbine runner 17.The exhaust gas, which is guided from the gas inlet to the turbine scroll flow path 31, is guided through the connecting path 29 and the turbine runner 17 to the outlet 27. The exhaust gas, which is guided to the outlet 27, rotates the turbine runner 17 as it passes therethrough.

[0017] The rotational force of the turbine impeller 17 is transmitted via the shaft 15 to the compressor impeller 19. As the compressor impeller 19 rotates, the air is pressurized, as described above. As such, the air is directed to the engine intake.

[0018] Fig. 2 is a first extract of an area that is Fig. 1 is enclosed by dashed lines. As in Fig. As shown in Figure 2, the bearing housing 3 has a radial bearing support 50. A bearing hole 3b is formed in the radial bearing support 50. A radial bearing 13 is provided within the radial bearing support 50 (bearing hole 3b). The radial bearing support 50 accommodates the radial bearing 13. The radial bearing support 50 holds the radial bearing 13.

[0019] The radial bearing support 50 has a recess 50a at the end closer to the compressor impeller 19. The recess 50a is located closer to the compressor impeller 19 with respect to the radial bearing 13. The recess 50a has a substantially circular ring shape. A central axis of the recess 50a is substantially equal to a central axis of the bearing hole 3b. The inner diameter of the recess 50a is larger than the inner diameter of the bearing hole 3b.

[0020] A pin hole 50b is formed in the radial bearing support 50. The pin hole 50b is formed vertically lower than the radial bearing 13. The pin hole 50b passes through the radial bearing support 50 in the radial direction of the shaft 15 (hereinafter referred to simply as the radial direction). The pin hole 50b extends, for example, vertically downward. A positioning pin 50c is press-fitted into the pin hole 50b. An insertion hole 13a is formed in the radial bearing 13 at a position radially facing the pin hole 50b. One end of the positioning pin 50c is inserted into the insertion hole 13a. The positioning pin 50c limits movements of the radial bearing 13 in the rotational direction and in the axial direction of the shaft 15 (hereinafter referred to simply as the axial direction).

[0021] Bearing surfaces 13b, which receive a radial load from the shaft 15, are formed on the inner surface of the radial bearing 13. In this embodiment, two bearing surfaces 13b, which are axially spaced from each other, are provided in the radial bearing 13. The inner diameters of the two bearing surfaces 13b are substantially equal to each other. The inner diameters of the two bearing surfaces 13b are substantially constant.

[0022] The shaft 15 has large-diameter portions 15a and a small-diameter portion 15b. The large-diameter portions 15a are arranged at positions facing the bearing surface 13b of the radial bearing 13 in the radial direction. In this embodiment, the shaft 15 has two large-diameter portions 15a that are axially spaced from each other because the radial bearing 13 has the two bearing surfaces 13b that are axially spaced from each other. The two large-diameter portions 15a have a substantially cylindrical shape. The outer diameters of the two large-diameter portions 15a are substantially equal to each other. The outer diameters of the two large-diameter portions 15a are slightly smaller than the inner diameters of the two bearing surfaces 13b. The outer diameters of the two large-diameter portions 15a are substantially constant.

[0023] The small-diameter portion 15b is arranged closer to the compressor impeller 19 with respect to the two large-diameter portions 15a. The small-diameter portion 15b has a substantially cylindrical shape. An outer diameter of the small-diameter portion 15b is substantially constant. The outer diameter of the small-diameter portion 15b is smaller than that of the large-diameter portion 15a. Accordingly, a step is formed between the large-diameter portion 15a and the small-diameter portion 15b.

[0024] The bearing housing 3 is provided with a turbine-side thrust ring 61, a compressor-side thrust ring (thrust bearing) 63, and a thrust collar (support portion) 65. The turbine-side thrust ring 61, the compressor-side thrust ring 63, and the thrust collar 65 are arranged between the radial bearing support 50 and the compressor impeller 19. The turbine-side thrust ring 61, the compressor-side thrust ring 63, and the thrust collar 65 are arranged closer to the compressor impeller 19 with respect to the radial bearing 13. However, the turbine-side thrust ring 61, the compressor-side thrust ring 63, and the thrust collar 65 may be arranged closer to the turbine impeller 17 with respect to the radial bearing 13 (see Fig. 1). The shaft 15 is inserted into the turbine-side thrust ring 61, the compressor-side thrust ring 63, and the thrust collar 65.

[0025] The turbine-side thrust ring 61 is closer to the turbine wheel 17 (see Fig. 1) is arranged in the recess 50a. The turbine-side thrust ring 61 has a substantially circular ring shape. The turbine-side thrust ring 61 is fixed to the bearing housing 3 (radial bearing support 50). The turbine-side thrust ring 61 is held non-rotatably by the radial bearing support 50. The large-diameter portion 15a of the shaft 15 is inserted into the turbine-side thrust ring 61. An inner diameter of the turbine-side thrust ring 61 is larger than the outer diameter of the large-diameter portion 15a. Furthermore, an outer diameter of the turbine-side thrust ring 61 is smaller than the inner diameter of the recess 50a. The compressor-side thrust ring 63 is located closer to the compressor impeller 19 with respect to the recess 50a. The compressor-side thrust ring 63 is arranged adjacent to the radial bearing support 50. The compressor-side thrust ring 63 essentially has a circular ring shape.The compressor-side thrust ring 63 is fixed to the bearing housing 3 (radial bearing support 50). The compressor-side thrust ring 63 is held non-rotatably by the radial bearing support 50. The small-diameter portion 15b of the shaft 15 is inserted into the compressor-side thrust ring 63. An inner diameter of the compressor-side thrust ring 63 is larger than the outer diameter of the small-diameter portion 15b. Furthermore, an outer diameter of the compressor-side thrust ring 63 is larger than the outer diameter of the turbine-side thrust ring 61 (the inner diameter of the recess 50a).

[0026] A groove 63a and a path 63b are formed in the compressor-side thrust ring 63. The groove 63a is formed in the compressor-side thrust ring 63 on a surface closer to the turbine impeller 17 (see Fig. 1). The path 63b is located radially inside the groove 63a. The path 63b has an output end 63c in the compressor-side thrust ring 63, which is open on the surface closer to the turbine impeller 17. The path 63b is connected at one end to an inner surface of the groove 63a and at the other end to the output end 63c.

[0027] In the recess 50a, the thrust collar 65 is located closer to the compressor impeller 19. The thrust collar 65 is located between the turbine-side thrust ring 61 (radial bearing 13) and the compressor-side thrust ring 63. The thrust collar 65 has a substantially circular ring shape. An inner diameter of the thrust collar 65 is substantially equal to or slightly larger than the outer diameter of the small-diameter portion 15b. An outer diameter of the thrust collar 65 is smaller than the inner diameter of the recess 50a. The thrust collar 65 is provided adjacent to the step formed between the large-diameter portion 15a and the small-diameter portion 15b of the shaft 15. However, the thrust collar 65 is not an essential component. For example, instead of the thrust collar 65, a portion of the shaft 15 may be formed to resemble an outer shape of the thrust collar 65.In that case, the part of the shaft 15 functions as the “support section” in the same way as the thrust collar 65.

[0028] The thrust collar 65 is, for example, press-fitted onto the small-diameter portion 15b. Accordingly, the thrust collar 65 rotates integrally with the shaft 15. Furthermore, the thrust collar 65 moves integrally with the shaft 15 in the axial direction.

[0029] An oil path 3c, a vertical supply path 3d, and a horizontal supply path 3e are formed in the bearing housing 3. A lubricant is supplied to the oil path 3c from outside the bearing housing 3. The oil path 3c is connected to the vertical supply path 3d and the horizontal supply path 3e.

[0030] The vertical supply path 3d is connected to the oil path 3c at one end and to the bearing hole 3b at the other end. The lubricant is supplied from the oil path 3c to the vertical supply path 3d. The vertical supply path 3d supplies the lubricant to the bearing hole 3b.

[0031] The horizontal supply path 3e is connected at one end to the oil path 3c and at the other end to the groove 63a of the compressor-side thrust ring 63. The lubricant is guided from the oil path 3c to the horizontal supply path 3e. The horizontal supply path 3e guides the lubricant to the groove 63a.

[0032] The lubricant supplied to the groove 63a is guided through the path 63b to the outlet end 63c, which is one end of the path 63b. The outlet end 63c is open on the compressor-side thrust ring 63 at a portion axially facing the thrust collar 65.

[0033] The lubricant supplied to the bearing hole 3b lubricates the radial bearing 13. A portion of the lubricant flows between the bearing surface 13b of the radial bearing 13 and the large-diameter portion 15a of the shaft 15. As a result, an oil film is formed between the bearing surface 13b and the large-diameter portion 15a. A radial load from the shaft 15 is supported by the oil film pressure of the lubricant. In other words, in the radial bearing 13, the bearing surface 13b radially facing the large-diameter portion 15a functions as the radial bearing surface that bears the radial load.

[0034] The lubricant that lubricates the radial bearing surfaces moves in the axial direction (in Fig. 2 left-right) inside the radial bearing support 50. The lubricant that is in Fig. 2 moves in the left direction, is guided to an oil chamber 80. The oil chamber 80 is formed below the radial bearing support 50, the turbine-side thrust ring 61, the compressor-side thrust ring 63 and the thrust collar 65. The lubricant, which is in Fig. 2 moves to the right direction, moves in this order to the turbine-side thrust ring 61 and the thrust collar 65. The lubricant that is in Fig. 2 moves in the right direction, lubricates between the turbine-side thrust ring 61 and the thrust collar 65. The lubricant that lubricates between the turbine-side thrust ring 61 and the thrust collar 65 moves in Fig. 2 down and to the right.

[0035] Furthermore, the lubricant supplied to the groove 63a of the compressor-side thrust ring 63 is discharged from the outlet end 63c through the path 63b. The lubricant discharged from the outlet end 63c lubricates between the compressor-side thrust ring 63 and the thrust collar 65. The lubricant lubricating between the compressor-side thrust ring 63 and the thrust collar 65 moves in Fig. 2 downwards and to the right. As such, the thrust collar 65 is supplied with lubricant from both sides in the axial direction. As a result, oil films are formed between the thrust collar 65 and the turbine-side thrust ring 61, and between the thrust collar 65 and the compressor-side thrust ring 63. The axial load from the thrust collar 65 (shaft 15) is supported by an oil film pressure of the lubricant. In other words, in the turbine-side thrust ring 61 and the compressor-side thrust ring 63, the surfaces axially facing the thrust collar 65 function as thrust bearing surfaces that absorb the thrust load.

[0036] An oil slinger 90 is arranged between the thrust collar 65 and the compressor impeller 19. The oil slinger 90 has a substantially cylindrical shape. The small-diameter portion 15b of the shaft 15 is inserted into the oil slinger 90. The oil slinger 90 rotates integrally with the shaft 15. The oil slinger 19 is arranged radially inside the compressor-side thrust ring 63. The oil slinger 90 distributes the lubricant flowing along the shaft 15 radially outward toward the compressor impeller 19.

[0037] On the back of the compressor impeller 19 (left in Fig. 2) A seal plate 100 is arranged. The seal plate 100 is fixed to the bearing housing 3. The seal plate 100 is held non-rotatably by the bearing housing 3. The seal plate 100 has a substantially circular ring shape. The small-diameter portion 15b of the shaft 15 and the oil slinger 90 are inserted into the seal plate 100. The seal plate 100 inhibits leakage of the lubricant distributed by the oil slinger 90 to the compressor impeller 19.

[0038] An oil drainage path 50d is formed in the radial bearing support 50. In the radial bearing support 50, the oil drainage path 50d is opened at one end on at least one of a surface facing the compressor-side thrust ring 63 and a surface facing the thrust collar 65, and at the other end on an outer surface (bottom surface) of the radial bearing support 50. In the present embodiment, the oil drainage path 50d is a through hole passing between the inner surface of the recess 50a and the outer surface (bottom surface) of the radial bearing support 50. Therefore, the lubricant lubricating between the turbine-side thrust ring 61 and the thrust collar 65 is guided to the oil drainage path 50d. Furthermore, the lubricant lubricating between the thrust collar 65 and the compressor-side thrust ring 63 is guided to the oil drainage path 50d. The oil drainage path 50d has a substantially constant inner diameter.The opening of the oil drainage path 50d formed on the outer surface of the radial bearing support 50 is located between the positioning pin 50c (pin hole 50b) and the compressor-side thrust ring 63.

[0039] A part of the lubricant that lubricates the turbine-side thrust ring 61, the compressor-side thrust ring 63 and the thrust collar 65 moves in Fig. 2 and is guided to the oil chamber 80 through the oil drainage path 50d. An oil outlet 110 is formed on a vertically lower side of the oil chamber 80. The oil outlet 110 is connected to the oil chamber 80 and is open to the outside of the bearing housing 3. The lubricant guided to the oil chamber 80 falls under its own weight and is discharged to the outside of the bearing housing 3 through the oil outlet 110.

[0040] Furthermore, a part of the lubricant that lubricates the turbine-side thrust ring 61, the compressor-side thrust ring 63 and the thrust collar 65 moves in Fig. 2 to the right and is led to an oil drainage chamber 120. The oil drainage chamber 120 is defined between the compressor-side thrust ring 63 and the seal plate 100 (compressor impeller 19). The oil drainage chamber 120 is continuous with the oil chamber 80 without the oil drainage path 50d. The lubricant led to the oil drainage chamber 120 is distributed by the oil slinger 90. The oil drainage chamber 120 guides the distributed lubricant through the oil chamber 80 to the oil outlet 110. The oil outlet 110 discharges the guided lubricant to the outside of the bearing housing 3.

[0041] The oil drainage chamber 120 is formed opposite the oil drainage path 50d via the compressor-side thrust ring 63. The oil drainage path 50d has an angle that inclines toward a direction spaced apart from the oil drainage chamber 120 when moving vertically downward. By forming the oil drainage chamber 120 and the oil drainage path 50d separately at different positions, the lubricant passing through the oil drainage chamber 120 and the lubricant passing through the oil drainage path 50d are less likely to mix (combine). As a result, the discharge of lubricant can be improved.

[0042] If a wall surface 80a forming the oil chamber 80 of the bearing housing 3 is located on an extension of the oil drainage path 50d, the lubricant passing through the oil drainage path 50d will collide with the wall surface 80a. In such a case, where the lubricant collides with the wall surface, the flow of lubricant discharged from the oil outlet 110 is disrupted. If the flow of lubricant is disrupted, it is difficult for the lubricant in the oil chamber 80 to be discharged from the oil outlet 110, and the lubricant is likely to remain in the oil chamber 80.

[0043] If the lubricant is likely to remain, the lubricant may escape from the bearing housing 3 to the turbine side or to the compressor side.

[0044] Accordingly, the inclination angle of the oil drainage path 50d with respect to the horizontal plane is adjusted so that the wall surface 80a is not located on the extension of the oil drainage path 50d. As a result, the entire projection area S1 of the oil drainage path 50d, which is projected along a central axis O to the oil outlet 110, is contained within the oil outlet 110. In the oil outlet 110, the projection area S1 is located on a side spaced from the oil drainage space 120 (ie, the left side in Fig. 2). The positioning pin 50c is not located on the extension of the oil drainage path 50d. In other words, the positioning pin 50c is located outside the area on the extension of the oil drainage path 50d.

[0045] This allows the lubricant moving along the central axis O of the oil drainage path 50d to be guided directly to the oil outlet 110. The lubricant moving along the central axis O of the oil drainage path 50d is less likely to impact the wall surface 80a. Accordingly, the discharge of the lubricant at the oil outlet 110 can be improved. As a result, the bearing housing 3 can reduce lubricant leakage.

[0046] In this embodiment, when machining the oil drainage path 50d, a tool is inserted from the oil outlet 110. This allows the inclination angle of the oil drainage path 50d with respect to the horizontal plane to be larger compared to the case where the tool is inserted from an opening on a compressor side of the bearing housing 3.

[0047] If the tool is inserted from the opening on the compressor side of the bearing housing 3 to machine the oil drainage path 50d, the tool and an upper part of the bearing housing 3 interfere with each other. Accordingly, it is difficult to adjust the inclination angle of the oil drainage path 50d with respect to the horizontal plane so that the entire projection area S1 of the oil drainage path 50d is contained within the oil outlet 110.

[0048] In contrast, when the tool is inserted from the oil outlet 110 to machine the oil drainage path 50d, the tool and the upper part of the bearing housing 3 do not interfere with each other. Accordingly, the inclination angle of the oil drainage path 50d with respect to the horizontal plane can be easily adjusted so that the entire projection area S1 of the oil drainage path 50d is contained within the oil outlet 110.

[0049] Fig. 3 is a second extract of the area shown in Fig. 1 is enclosed by the dashed lines. As in Fig. 3, the entire projected area S2 of the opening of the oil drainage path 50d on the outer surface (bottom surface) of the radial bearing support 50, which is projected along the vertical direction to the oil outlet 110, is contained within the oil outlet 110.

[0050] This makes it difficult for the lubricant to hit the wall surface 80a even when it falls vertically downward from the opening of the oil drainage path 50d on the outer surface. This improves the discharge of the lubricant from the oil outlet 110. As a result, the bearing housing 3 can reduce lubricant leakage.

[0051] Although the embodiment of the present invention has been described above with reference to the accompanying drawings, the present invention is not limited thereto. It is apparent that a person skilled in the art can devise various examples of variations or modifications within the scope of the claims, which are also understood to be within the technical scope of the present invention.

[0052] The above embodiment describes an example in which the entire projection area S2 is contained within the oil outlet 110. However, the present invention is not limited thereto, and the entire projection area S2 does not need to be contained within the oil outlet 110. For example, a part of the projection area S2 may overlap with the wall surface 80a. List of reference symbols

[0053] 13: Radial bearing, 15: Shaft, 19: Compressor impeller (wheel), 50: Radial bearing support, 50d: Oil drainage path, 60: Turbine-side thrust ring, 63: Compressor-side thrust ring (thrust bearing), 65: Thrust collar (support section), 80: Oil chamber, 80a: Wall surface, 110: Oil outlet, 120: Oil drainage space, S1: Projection surface, S2: Projection surface, TC: Turbocharger

Claims

[1] Turbocharger (TC) with: a radial bearing support (50) having a bearing hole (3b); a radial bearing (13) provided in the bearing hole (3b); a shaft (15) inserted into the radial bearing (13); an impeller (19) provided on the shaft (15); a thrust bearing (63) into which the shaft (15) is inserted, the thrust bearing (63) being arranged between the radial bearing support (50) and the impeller (19); a support portion (65) provided on the shaft (15) and arranged between the radial bearing (13) and the thrust bearing (63); an oil chamber (80) formed below the radial bearing support (50) and the thrust bearing (63); an oil outlet (110) connected to the oil chamber (80) and open to an outside; an oil drainage path (50d) formed in the radial bearing support (50), wherein one end of the oil drainage path (50d) in the radial bearing support (50) is opened at least on one of a surface facing the thrust bearing (63) and a surface facing the support portion (65), another end of the oil drainage path (50d) is opened on a bottom surface of the radial bearing support (50), wherein an entire projected area (S1) of the oil drainage path (50d) projected along a central axis (O) thereof to the oil outlet (110) is contained within the oil outlet (110); and an oil drainage chamber (120) provided between the thrust bearing (63) and the impeller (19) and connected to the oil chamber (80). [2] The turbocharger (TC) according to claim 1, wherein an entire projected area (S2) of an opening of the oil drainage path (50d) on the bottom surface of the radial bearing support (50) projected along the vertical direction to the oil outlet (110) is contained within the oil outlet (110).

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