Turbocharger bushing and turbocharger

Abstract

Turbocharger bushing (18) with cylindrical shape, wherein at least one recess (26) is formed on an inner peripheral surface of the socket (18) at a position remote from at least one end of the two ends of the socket (18), wherein the at least one recess (26) includes at least one axial recess (26B) extending along an axial direction of the bushing (18), wherein the at least one axial recess (26B) includes a plurality of axial recesses (26B) which are arranged at intervals in a circumferential direction of the bushing (18).

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a turbocharger bushing and a turbocharger. BACKGROUND

[0002] Patent Document 1 discloses a bushing that supports a shaft portion of an opening / closing lever connected to a wastegate valve of a turbocharger while allowing the shaft portion to rotate. The bushing has a groove formed from one end to the other end of the bushing in the axial direction to collect particles that cause adhesion between the shaft portion and the bushing. Citation listPatent literature

[0003] Patent document 1: US 9 546 597 B2, patent document 2: CN 1 06 285 919 A, patent document 3: CN 2 01 062 538 Y, patent document 4: DE 10 2018 217 602 A1, patent document 5: DE 10 2015 101 364 A1, patent document 6: DE 10 2015 114 935 A1. SUMMARYProblems to be solved

[0004] As described above, since the groove formed in the bushing disclosed in Patent Document 1 extends from one end to the other end of the bushing, exhaust gas flowing inside the turbocharger is likely to flow out of the turbocharger through the groove.

[0005] In view of the above, it is an object of at least one embodiment of the present invention to provide a turbocharger bushing and a turbocharger, wherein it is possible to suppress the leakage of exhaust gas while suppressing the adhesion between the bushing and the shaft part. Solutions to the problems

[0006] (1) A turbocharger bushing according to at least one embodiment of the present invention has a cylindrical shape with at least one recess formed on an inner peripheral surface of the bushing at a position remote from at least one end of the both ends of the bushing.

[0007] In the turbocharger bushing (1) described above, particles that cause adhesion between the bushing and the shaft part are collected in the recess, so that adhesion between the bushing and the shaft part can be suppressed. Herein, the term "particles" includes, for example, abrasion powder generated by friction between the bushing and the shaft part and salt crystals generated by evaporation of salt water that has penetrated from outside the turbocharger into a space between the bushing and the shaft part.

[0008] Since particles causing adhesion between the bushing and the shaft part tend to accumulate in the recess on the inner peripheral surface of the bushing due to the centrifugal force caused by the rotation of the shaft part, the adhesion between the bushing and the shaft part can be effectively suppressed compared with the case where the recess is formed on the outer peripheral surface of the shaft part.

[0009] In addition, since the recess is formed away from at least one of the two ends of the bushing, exhaust gas flowing inside the turbocharger housing can be prevented from flowing out through a space between the bushing and the shaft part, compared with the case where the groove is formed from one end to the other end of the bushing as in the configuration of Patent Document 1.

[0010] (2) In some embodiments, in the turbocharger bushing described in (1) above, the at least one recess includes a recess formed at a position away from both ends of the bushing.

[0011] In the turbocharger bushing described in (2) above, since the recess is formed away from both ends of the bushing, exhaust gas flowing inside the turbocharger housing can be effectively prevented from flowing out through a space between the bushing and the shaft part.

[0012] (3) In some embodiments, the at least one recess in the turbocharger bushing described in (1) above includes a recess connected to the other end of the two ends of the bushing.

[0013] With the turbocharger bushing described in (3) above, exhaust gas flowing inside the turbocharger housing can be prevented from flowing out through a space between the bushing and the shaft part, while particles collected in the recess are removed from the other end of the bushing.

[0014] (4) In some embodiments, in the turbocharger bushing described in any one of (1) to (3) above, the at least one recess includes a recess having a central position offset from a central position of the bushing in an axial direction of the bushing.

[0015] In the turbocharger bushing described in (4) above, since the bushing can be arranged so that the center of the recess is closer to the outside of the housing than the central position of the bushing, particles accumulated in the recess can be effectively discharged to the outside of the housing by the pressure difference between the inside and outside of the housing.

[0016] (5) In some embodiments, in the turbocharger bushing described in (4) above, the at least one recess includes a recess group consisting of a plurality of recesses, and wherein a central position of the recess group is offset from the central position of the bushing in the axial direction of the bushing.

[0017] In the turbocharger bushing described in (5) above, since the bushing can be arranged so that the central position of the recess group is closer to the outside of the housing than the central position of the bushing, particles accumulated in the recess group can be effectively discharged to the outside of the housing by the pressure difference between the inside and outside of the housing.

[0018] (6) In some embodiments, the at least one recess in the turbocharger bushing described in any one of (1) to (5) above includes at least one circumferential recess extending along a circumferential direction of the bushing.

[0019] In the turbocharger bushing described in (6) above, compared with the case where the recess extends along the axial direction, exhaust gas flowing inside the turbocharger housing can be effectively prevented from flowing out through a space between the bushing and the shaft part.

[0020] (7) In some embodiments, in the turbocharger bushing described in (6) above, the at least one circumferential recess includes an annularly shaped recess.

[0021] With the turbocharger bushing described in (7) above, exhaust gas flowing inside the turbocharger housing can be effectively prevented from flowing out through a space between the bushing and the shaft part, compared with the case where the recess extends along the axial direction.

[0022] (8) In some embodiments, the at least one circumferential recess in the turbocharger bushing described in (6) or (7) above includes a plurality of circumferential recesses arranged at intervals in an axial direction of the bushing.

[0023] In the turbocharger bushing described in (8) above, since the plurality of recesses in the circumferential direction forms a labyrinth structure between the bushing and the shaft part, leakage of exhaust gas flowing inside the turbocharger housing through a space between the bushing and the shaft part can be effectively prevented.

[0024] (9) In one embodiment of the present invention, the at least one recess in the turbocharger bushing described in any one of the above items (1) to (5) includes at least one axial recess extending along an axial direction of the bushing.

[0025] In the turbocharger bushing described in (9) above, during the rotation of the shaft part, particles that cause adhesion to the outer peripheral surface of the shaft part can be scraped into the axial recess. Accordingly, it is possible to effectively suppress adhesion between the bushing and the shaft part.

[0026] (10) In one embodiment of the present invention, the at least one axial recess in the turbocharger bushing described in (9) above includes a plurality of axial recesses arranged at intervals in a circumferential direction of the bushing.

[0027] In the turbocharger bushing described in (10) above, during the rotation of the shaft part, particles that cause adhesion to the outer peripheral surface of the shaft part can be scraped into the plurality of axial recesses. Accordingly, it is possible to effectively suppress adhesion between the bushing and the shaft part.

[0028] (11) In some embodiments, the at least one recess in the turbocharger bushing described in any one of (1) to (5) above includes a spiral recess formed in a spiral around an axis of the bushing.

[0029] In the turbocharger bushing described in (11) above, the spiral recess provides both the exhaust gas outflow suppression effect of the labyrinth structure and the adhesion suppression effect between the bushing and the shaft part by scraping particles.

[0030] (12) In some embodiments, the at least one recess in the turbocharger bushing described in any one of the above items (1) to (5) includes a plurality of recesses each offset from each other in an axial direction of the bushing and a circumferential direction of the bushing.

[0031] In the turbocharger bushing described in (12) above, since the recesses are offset from each other in both the axial direction and the circumferential direction, exhaust gas flowing inside the turbocharger housing can be effectively prevented from flowing out through a space between the bushing and the shaft part, and particles causing adhesion to the outer peripheral surface of the shaft part can be scraped into the recesses to effectively suppress adhesion between the bushing and the shaft part.

[0032] (13) A turbocharger according to at least one embodiment of the present invention comprises: a housing having a flow channel for an exhaust gas formed inside the housing; a shaft part extending from the inside to the outside of the housing; and a bushing fixed to the housing and supporting the shaft part while allowing the shaft part to rotate. The bushing is the bushing described in any one of (1) to (12) above.

[0033] In the turbocharger (13) described above, since the bushing described in any one of the above items (1) to (12) is included, it is possible to suppress the exhaust gas leakage while suppressing the adhesion between the bushing and the shaft part.

[0034] (14) In some embodiments, in the turbocharger described in (13) above, the at least one recess includes a recess having a central position that is closer to the outside of the housing than a central position of the bushing in an axial direction of the bushing.

[0035] In the turbocharger (14) described above, since the inner peripheral surface of the bushing has the recess with the central position closer to the outside of the housing than the central position of the bushing, particles accumulated in the recess can be easily discharged to the outside of the housing.

[0036] (15) In some embodiments, in the turbocharger described in (14) above, the at least one recess includes a recess group consisting of a plurality of recesses, and a central position of the recess group is closer to the outside of the housing than the central position of the sleeve in the axial direction of the sleeve.

[0037] In the turbocharger (15) described above, since the central position of the recess group is closer to the outside of the housing than the central position of the bushing, particles accumulated in the recess group can be easily discharged to the outside of the housing. Beneficial effects

[0038] At least one embodiment of the present invention provides a turbocharger bushing and a turbocharger, wherein it is possible to suppress exhaust gas leakage while suppressing adhesion between the bushing and the shaft part. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic block diagram showing a configuration of a turbocharger 100 according to an embodiment. Fig. 2 is a vertical cross-sectional view of a drive part of a Fig. 1 shown wastegate valve 8. Fig. 3 is a cross-sectional view taken along line AA in Fig. 2. Fig. 4 is a schematic cross-sectional view of a bushing 18 according to an embodiment, taken along the axial direction. Fig. 5 is a schematic cross-sectional view of a bushing 18 according to another embodiment, taken along the axial direction. Fig. 6 is a schematic cross-sectional view of a bushing 18 according to another embodiment, taken along the axial direction. Fig. 7 is a schematic cross-sectional view of a bushing 18 according to another embodiment, taken in the axial direction. Fig. 8 is a schematic cross-sectional view of a bushing 18 according to another embodiment, taken in the axial direction. Fig. 9 is a schematic cross-sectional view of a bushing 18 according to another embodiment, taken in the axial direction. Fig. 10 is a schematic cross-sectional view of a bushing 18 according to another embodiment, taken in the axial direction. Fig. 11 is a schematic cross-sectional view of a bushing 18 according to another embodiment, taken in the axial direction. Fig. 12 is a schematic cross-sectional view of a bushing 18 according to another embodiment, taken in the axial direction. Fig. 13 is a cross-sectional view showing a partial configuration of a turbocharger 200 according to an embodiment. Detailed description

[0039] Embodiments of the present invention will now be described in detail with reference to the accompanying drawings. However, unless specifically indicated, dimensions, materials, shapes, relative positions, and the like of components described in the embodiments are intended to be interpreted as illustrative only and are not intended to limit the scope of the present invention.

[0040] For example, the expression of a relative or absolute arrangement such as "in one direction", "along one direction", "parallel", "orthogonal", "centered", "concentric" and "coaxial" should not be understood to indicate only the arrangement in the strict sense of the word, but also to include a state in which the arrangement is relatively shifted by a tolerance or by an angle or a distance, whereby it is possible to achieve the same function.

[0041] For example, an expression of a same state such as "same," "equal," and "uniform" should not be understood to indicate only the state in which the characteristic is strictly the same, but also to include a state in which there is a tolerance or difference with which the same function can still be achieved.

[0042] Furthermore, for example, an expression such as “rectangular shape” or “cylindrical shape” should not only be understood as the geometrically strict shape, but also includes a shape with unevenness or bevelled corners within the range in which the same effect can be achieved.

[0043] On the other hand, expressions such as “comprise”, “include”, “have”, “contain” and “form” should not be understood as excluding other components.

[0044] Fig. 1 is a schematic block diagram showing a configuration of a turbocharger 100 according to an embodiment. As shown in Fig. 1, the turbocharger 100 includes a turbine 2 configured to be rotated by exhaust gas from an engine (not shown), a compressor 4 configured to be driven by the turbine 2 to compress intake air of the engine, and a wastegate valve 8 for opening and closing a bypass passage 6 bypassing the turbine 2.

[0045] Fig. 2 is a vertical cross-sectional view of a drive part of the Fig. 1 shown wastegate valve 8. Fig. 3 is a cross-sectional view taken along the line AA in Fig. 2 was recorded.

[0046] As in at least one of the Fig. 1 and Fig. As shown in Figure 3, the bypass passage 6 branches off from an exhaust passage 12 connecting an exhaust inlet 10 of the turbocharger 100 to the turbine 2, and is configured so that exhaust gas discharged from the exhaust passage 12 bypasses the turbine and is guided to the downstream side of the turbine 2. The bypass passage 6 is formed in a housing 24 of the turbocharger 100.

[0047] As in at least one of the Fig. 2 and Fig. 3, the wastegate valve 8 includes a valve body 14 disposed in the bypass passage 6, an opening / closing lever 16 connected to the valve body 14 and configured to move the valve body 14 to open or close the bypass passage 6, and a bushing 18. In the illustrated embodiments, the opening / closing lever 16 is L-shaped and configured such that when a shaft part 20 on the base side rotates about an axis 20a, an operating part 22 (connected to the valve body 14) on the tip side rotates the valve body 14 about the axis 20a to open or close the bypass passage 6.

[0048] As in Fig. 2, the bushing 18 is cylindrically shaped. The bushing 18 is secured to the housing 24 by fitting an outer peripheral surface 18a of the bushing 18 into a through hole 24a of the housing 24. In the illustrated embodiment, the bushing 18 extends outwardly from the inside of the housing 24, penetrating the housing 24.

[0049] The shaft part 20 extends from the inside to the outside of the housing 24 to penetrate the housing 24. The shaft part 20 is inserted into the bushing 18, and an inner peripheral surface 18b of the bushing 18 is configured to support the shaft part 20 of the opening / closing lever 16 while allowing the shaft part 20 to rotate.

[0050] Next, with reference to the Fig. 4 to 12, configuration examples of the socket 18 according to some embodiments are described. Fig. The embodiments shown in Figures 4 to 12 differ in the shape of the inner peripheral surface 18b of the bushing 18. Hereinafter, the axial direction of the bushing 18 is simply referred to as the “axial direction,” and the circumferential direction of the bushing 18 is simply referred to as the “circumferential direction.”

[0051] In some embodiments, for example as in Fig. 4 to 12, at least one recess 26 is formed on the inner peripheral surface 18b of the bushing 18 at a position remote from at least one end (18c and / or 18d) of the two ends 18c, 18d of the bushing 18.

[0052] In this configuration, particles that cause adhesion between the bushing 18 and the shaft part 20 are collected in the recess 26, so that adhesion between the bushing 18 and the shaft part 20 can be suppressed. The term "particles" here includes, for example, abrasion powder generated by friction between the bushing 18 and the shaft part 20, salt crystals generated by evaporation of salt water that has entered a space between the bushing 18 and the shaft part 20 from outside the turbocharger 100, and other particles and combinations of these particles.

[0053] In particular, since hot exhaust gas flows inside the housing 24, no lubricant is used between the bushing 18 and the shaft part 20, and the abrasion powder is likely to be generated. Therefore, by trapping the abrasion powder in the recess 26 to hold the abrasion powder, it is possible to effectively suppress the adhesion between the bushing 18 and the shaft part 20. When the turbocharger is an automotive turbocharger, adhesion between the bushing and the shaft part is likely, particularly due to the salt crystals, but the turbocharger 100 can effectively suppress the adhesion between the bushing and the shaft part caused by the salt crystals.

[0054] In addition, since particles causing adhesion between the bushing 18 and the shaft part 20 tend to accumulate in the recess 26 on the inner peripheral surface 18b of the bushing 18 due to the centrifugal force caused by the rotation of the shaft part 20, the adhesion between the bushing 18 and the shaft part 20 can be effectively suppressed compared to the case where the recess is formed on the outer peripheral surface of the shaft part 20.

[0055] In addition, since the recess 26 is formed away from at least one of the two ends 18c, 18d of the sleeve 18, exhaust gas flowing inside the housing 24 of the turbocharger 100 can be prevented from flowing out through a space between the sleeve 18 and the shaft part 20, compared with the case where the groove is formed from one end to the other end of the sleeve 18 as in the configuration of Patent Document 1.

[0056] In some embodiments, for example as in the Fig. As shown in Figures 4 to 12, the hardness of the bushing 18 is higher than the hardness of the shaft portion 20. In this case, the materials of the bushing 18 and the shaft portion 20 are not limited. For example, the material of the bushing 18 may be a sintered austenitic stainless steel, and the material of the shaft portion 20 may be a heat-resistant cast steel such as SCH21.

[0057] As described above, when the hardness of the bushing 18 is higher than the hardness of the shaft part 20, the abrasion of the inner peripheral surface 18b of the bushing 18 due to the friction between the bushing 18 and the shaft part 20 can be suppressed, compared with the case where the hardness of the shaft part 20 is higher than the hardness of the bushing 18. In this case, the effect of collecting particles that cause adhesion between the bushing 18 and the shaft part 20 in the recess 26, which prevents the recess 26 on the inner peripheral surface 18b of the bushing 18 from deforming and becoming shallower due to abrasion, can be maintained for a long time.

[0058] In some embodiments, for example as in the Fig. 4 to 8 and 10 to 12, the at least one recess 26 on the inner peripheral surface 18b of the bushing 18 includes a recess 26 formed at a position remote from the two ends 18c, 18d of the bushing 18.

[0059] With this configuration, since the recess 26 is formed away from both ends 18c, 18d of the sleeve 18, exhaust gas flowing inside the housing 24 of the turbocharger 100 can be effectively prevented from flowing out through a space between the sleeve 18 and the shaft part 20.

[0060] Furthermore, as for example in Fig. 4 and Fig. 5, since the main areas X and Y in which the bushing 18 receives the torque T from the shaft part 20 are both ends of the bushing 18, if the recess 26 is formed away from both ends 18c, 18d, the above-mentioned effect of the recess 26 can be achieved while securing the area of ​​the inner peripheral surface 18b of the bushing 18 that contributes to supporting the shaft part 20.

[0061] Furthermore, according to the inventors' findings, the abrasion powder tends to accumulate near the axial central position M of the bushing 18. Therefore, if the recess 26 is formed away from the two ends 18c, 18d of the bushing 18, the abrasion powder can be effectively trapped in the recess 26. In particular, if the recess 26 is formed in a region including the axial central position M, it is possible to effectively suppress adhesion between the bushing 18 and the shaft part 20 due to the abrasion powder.

[0062] In some embodiments, for example as in Fig. 9, the at least one recess 26 on the inner peripheral surface 18b of the bushing 18 includes a recess 26 that is remote from one end 18c and adjacent to the other end 18d of the two ends 18c, 18d of the bushing 18. In the exemplary embodiment shown in Fig. 9, the recess 26 adjoins the end 18d of the two ends 18c, 18d of the bushing 18, which is arranged outside the housing 24.

[0063] With this configuration, exhaust gas flowing within the housing 24 of the turbocharger 100 can be prevented from flowing out through a space between the sleeve 18 and the shaft part 20, while particulates collected in the recess 26 are removed from the other end of the sleeve 18.

[0064] In some embodiments, for example as in Fig. 5, Fig. 7, Fig. 9 and Fig. 12, the at least one recess 26 on the inner peripheral surface 18b of the bushing 18 includes a recess 26 having the central position m that is axially offset from the central position M of the bushing 18. In the illustrated embodiment, the at least one recess 26 includes a recess 26 having the central position m that is closer to the outside of the housing 24 than the central position M of the bushing 18 in the axial direction.

[0065] Since the pressure inside the housing 24 of the turbocharger 100 is higher than the pressure outside the housing 24, particles accumulated in the recess 26 can be effectively discharged to the outside of the housing 24 by the pressure difference between the inside and outside of the housing 24 when the central position m of the recess 26 is closer to the outside of the housing 24 than the central position M of the bushing 18.

[0066] In some embodiments, for example as in the Fig. 6 to 10, the at least one recess 26 on the inner peripheral surface 18b of the bushing 18 includes a recess group 28 consisting of a plurality of recesses 26. In the embodiments as shown in the Fig. 7 and Fig. 9, the central position N of the recess group 28 is offset in the axial direction from the central position M of the bushing 18 and is closer to the outside of the housing 24 than the central position M of the bushing 18.

[0067] As described above, when the bushing 18 is arranged such that the central position N of the recess group 28 is closer to the outside of the housing 24 than the central position M of the bushing 18, particles accumulated in the recess group 28 can be effectively discharged to the outside by the pressure difference between the inside and outside of the housing 24. In other embodiments, the central position N of the recess group 28 may be closer to the inside of the housing 24 in the axial direction than the central position M of the bushing 18.

[0068] In some embodiments, for example as in Fig. As shown in Figures 4 to 7, the at least one recess 26 on the inner peripheral surface 18b of the bushing 18 includes at least one circumferential recess 26A (circumferential groove) extending along the circumferential direction. In the illustrated embodiments, each circumferential recess 26A is annularly shaped.

[0069] With this configuration, exhaust gas flowing inside the housing 24 of the turbocharger 100 can be effectively prevented from flowing out through a space between the sleeve 18 and the shaft part 20, compared with the case where the recess 26 extends along the axial direction.

[0070] In some embodiments, for example as in Fig. 6 and Fig. 7, the at least one circumferential recess 26A on the inner peripheral surface 18b of the bushing 18 includes a plurality of circumferential recesses 26A arranged at intervals in the axial direction.

[0071] With this configuration, since the plurality of circumferential recesses 26A form a labyrinth structure in the circumferential direction between the sleeve 18 and the shaft part 20, exhaust gas flowing within the housing 24 of the turbocharger 100 can be effectively prevented from flowing out through a space between the sleeve 18 and the shaft part 20.

[0072] In some embodiments, for example as in Fig. As shown in Figures 8 to 10, the at least one recess 26 on the inner peripheral surface 18b of the bushing 18 includes at least one axial recess 26B (axial groove) extending along the axial direction. In the illustrated embodiments, the at least one axial recess 26B includes a plurality of axial recesses 26B spaced circumferentially.

[0073] With this configuration, during rotation of the shaft part 20, particles that cause adhesion to the outer peripheral surface of the shaft part 20 can be scraped into the axial recess 26. Accordingly, it is possible to effectively suppress adhesion between the bushing 18 and the shaft part 20.

[0074] In some embodiments, for example as in Fig. 10, the at least one recess 26 on the inner peripheral surface 18b of the bushing 18 includes a plurality of recesses 26 that are offset from one another in both the axial direction and the circumferential direction.

[0075] With this configuration, since the recesses 26 are offset from each other in both the axial direction and the circumferential direction, exhaust gas flowing inside the housing 24 of the turbocharger 100 can be effectively prevented from flowing out through a space between the bushing 18 and the shaft part 20, and particles that cause adhesion to the outer peripheral surface of the shaft part 20 can be scraped into the recesses 26 to effectively suppress adhesion between the bushing 18 and the shaft part 20.

[0076] In some embodiments, for example as in Fig. 11 and Fig. 12, the at least one recess 26 on the inner peripheral surface 18b of the bushing 18 includes a spiral recess 26C (spiral groove) formed in a spiral around the axis of the bushing 18.

[0077] With this configuration, the spiral recess 26 provides both the exhaust gas outflow suppression effect of the labyrinth structure and the adhesion suppression effect between the bushing 18 and the shaft part 20 by scraping in particles.

[0078] The present invention is not limited to the above-described embodiments, but includes modifications of the above-described embodiments and embodiments consisting of combinations of these embodiments.

[0079] For example, in the embodiments described above, the bushing 18 for rotatably supporting the shaft part 20 of the opening / closing lever 16 of the wastegate valve 8 was described. Fig. 4 to 12 can be used to rotatably support a control crank 39 of a variable geometry turbocharger 200, such as in Fig. 13 and described below.

[0080] Fig. 13 is a schematic cross-sectional view of a variable geometry turbocharger 200 according to an embodiment of the present invention, taken along the rotational axis of the turbocharger 200.

[0081] As in Fig. As shown in Figure 13, the turbocharger 200 is provided with a cylindrical turbine housing 3, and the turbine housing 3 has a scroll 5 shaped like a spiral. A turbine rotor 7 is arranged in the turbine housing 3.

[0082] A turbine shaft 9, on which the turbine rotor 7 is mounted, is coaxial with a compressor (not shown). The turbine shaft 9 is rotatably mounted in a bearing housing 13 via a bearing 11.

[0083] A variable nozzle mechanism 23, which is a nozzle assembly including nozzles 19 and a nozzle holder 21, is mounted on the side of the bearing housing 13 adjacent to the scroll 5. The nozzles 19 are arranged at intervals around the rotational axis K of the turbine shaft 9. The nozzles 19 are arranged radially within the scroll 5.

[0084] Each nozzle 19 has a nozzle vane 19a and a nozzle shaft 19b. The nozzle shafts 19b are rotatably supported by the nozzle carrier 21 attached to the bearing housing 13. The bearing parts of the nozzle shafts 19b are arranged at equal intervals around the rotation axis K. This variable nozzle mechanism 23 allows the vane angles of the nozzle vanes 19a to be changed.

[0085] The nozzle vanes 19a are arranged between the nozzle carrier 21 and an annular nozzle plate 27, which are connected to the nozzle carrier 21 such that they are opposite the nozzle carrier 21 at a predetermined distance in the turbine axial direction by a nozzle carrier 25. The nozzle plate 27 is attached to the end face of the inner cylinder of the turbine housing 3.

[0086] The nozzle holder 21 has a step 29 in the radial direction, into which a disc-shaped drive ring 31 is rotatably inserted concentrically with the rotation axis K. The drive ring 31 engages with a plurality of circumferentially arranged lever plates 33. One end of the lever plate 33 is fixed to the drive ring 31, and the other end is connected to the end of the nozzle shaft 19b, which projects into the interior of the nozzle holder 21 in the same direction as the rotation axis K.

[0087] The nozzle shafts 19b and the nozzle vane 19a are rotated according to the angle at which the drive ring 31 is rotated about the rotation axis K. In other words, the opening degree of the nozzle 19 can be adjusted by rotating the drive ring 31.

[0088] The variable nozzle mechanism 23 is an assembly that includes the nozzles 19 (19a, 19b), the nozzle carrier 21, the nozzle plate 27, the drive ring 31, and the lever plates 33. Furthermore, an annular storage part 17 is formed in a rear part 15 of the bearing housing 13. A connecting mechanism 35 is arranged in the storage part 17 and penetrates the rear part 15.

[0089] The link mechanism 35 includes an input lever 37 connected at one end to an actuator (not shown) for actuating the variable nozzle mechanism 23, a control crank 39 connected to the other end of the input lever 37 and disposed through the bearing housing 13, and an output lever 41 connected at one end to the control crank 39. The link mechanism 35 is configured to convert the reciprocating motion by the actuator into a rotary motion through the input lever 37, the control crank 39, and the output lever 41 to transmit a rotary force to the variable nozzle mechanism 23 mounted within the bearing housing 13.

[0090] In the Fig. In the embodiment shown in Figure 13, the turbocharger 200 is provided with a cylindrical bushing 18 to support a shaft portion 40 of the control crank 39 while allowing the shaft portion 40 to rotate. In the illustrated embodiment, the bushing 18 extends outward from the inside of the bearing housing 13 so that it penetrates the bearing housing 13. The bushing 18 is fixed to the bearing housing 13 by fitting an outer peripheral surface 18a of the bushing 18 into a through hole 13a of the bearing housing 13.

[0091] The shaft portion 40 of the control crank 39 extends outward from the inside of the bearing housing 13 so as to penetrate the bearing housing 13. The shaft portion 40 is inserted into the bushing 18, and an inner peripheral surface 18b of the bushing 18 is configured to support the shaft portion 40 of the control crank 39 while allowing the shaft portion 40 to rotate.

[0092] If the Fig.4 to 12 is used to rotatably support the shaft portion 40 of the control crank 39, it is possible to suppress the outflow of exhaust gas while suppressing adhesion between the bushing 18 and the shaft portion 40 of the control crank 39. List of reference symbols 2 turbines 3 turbine housings 4 compressors 5 snail 6 Bypass channel 7 Turbine rotor 8 Wastegate valve 9 Turbine shaft 10 Exhaust gas inlet 11 camps 12 exhaust duct 13 Bearing housing 13a Through hole 14 valve body 15 back part 16 opening / closing levers 17 Bearing part 18 socket 18a Outer peripheral surface 18b Inner peripheral surface 18c, 18d Both ends (one end, the other end) 19 Nozzle 19a Nozzle vane 19b Nozzle shaft 20 Shaft part 20a axle 21 Nozzle holder 22 Actuating part 23 Variable nozzle mechanism 24 housings 24a Through hole 25 nozzle carriers 26 recess 26A circumferential recess 26B Axial recess 26C Spiral recess 27 Nozzle plate 28 recess group 29th level 31 Drive ring 33 Lever plate 35 Connecting mechanism 37 Input lever 39 Control crank 40 Shaft part 41 Output lever 100, 200 turbocharger

Claims

[1] Turbocharger bushing (18) with cylindrical shape, wherein at least one recess (26) is formed on an inner peripheral surface of the bushing (18) at a position remote from at least one end of the two ends of the bushing (18), wherein the at least one recess (26) includes at least one axial recess (26B) extending along an axial direction of the bushing (18), wherein the at least one axial recess (26B) includes a plurality of axial recesses (26B) arranged at intervals in a circumferential direction of the bushing (18). [2] The turbocharger bushing (18) of claim 1, wherein the at least one recess (26) includes a recess (26) formed at a position remote from both ends of the bushing (18). [3] The turbocharger bushing (18) of claim 1, wherein the at least one recess (26) includes a recess (26) connected to the other end of the two ends of the bushing (18). [4] Turbocharger bushing (18) according to one of claims 1 to 3, wherein the at least one recess (26) includes a recess (26) having a central (m) position offset from a central position (M) of the bushing (18) in an axial direction of the bushing (18). [5] Turbocharger bushing (18) according to claim 4, wherein the at least one recess (26) includes a recess group (28) consisting of a plurality of recesses (26), and wherein a central position (N) of the recess group (28) is offset from the central position (M) of the bushing (18) in the axial direction of the bushing (18). [6] Turbocharger bushing (18) according to one of claims 1 to 5, wherein the at least one recess (26) includes a plurality of recesses (26) which are each offset from one another in an axial direction of the bushing (18) and a circumferential direction of the bushing (18). [7] Turbocharger (100, 200), comprising: a housing (24) having a flow channel for an exhaust gas formed inside the housing (24); a shaft part (20) extending from the inside to the outside of the housing (24); and a bushing (18) fixed to the housing (24) and supporting the shaft member (20) while allowing the shaft member (20) to rotate, wherein the socket (18) is the socket (18) according to one of claims 1 to 6. [8] The turbocharger (100, 200) of claim 7, wherein the at least one recess (26) includes a recess (26) having a central position (m) that is closer to the outside of the housing (24) than a central position (M) of the bushing (18) in an axial direction of the bushing (18). [9] Turbocharger (100, 200) according to claim 8, wherein the at least one recess (26) includes a recess group (28) consisting of a plurality of recesses (26), and wherein a central position (N) of the recess group (28) is closer to the outside of the housing (24) than the central position (M) of the bushing (18) in the axial direction of the bushing (18). [10] The turbocharger (100, 200) according to claim 7, wherein a central position (m) of each of the plurality of axial recesses (26B) is closer to the outside of the housing (24) than a central position (M) of the bushing (18) in the axial direction of the bushing (18).

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