Guide vane and turbocharger with variable geometry

Abstract

Guide vane (11) of a variable geometry turbocharger (1), comprising: a guide vane body (31) rotatably arranged in an exhaust gas passage (16) defined between a casing surface (41) and a hub surface (43); and a flange section (50) which is provided on at least one of a shell-side end face (51) or a hub-side end face (52) of the guide vane body (31) and is formed around a center of rotation (C) of the guide vane body (31), wherein the flange section (50) is designed such that it satisfies the following expression (i) or (ii): R1 < R2 R4 < R3 where R1 is the shortest distance from the center of rotation (C) to an outer edge (58) of the flange section (50) on the trailing edge side and on a suction surface (33) of the guide vane (11), R2 is the shortest distance from the center of rotation (C) to the outer edge of the flange section (50) on the leading edge side and on the suction surface (33) of the guide vane (11), R3 is the shortest distance from the center of rotation (C) to the outer edge of the flange section (50) on the leading edge side and on a pressure surface (32) of the guide vane (11), and R4 is the shortest distance from the center of rotation (C) to the outer edge of the flange section (50) on the trailing edge side and on the pressure surface (32) of the guide vane (11).

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a guide vane for a variable geometry turbocharger and such a turbocharger having such a guide vane. BACKGROUND

[0002] In recent years, various variable geometry turbochargers have been developed that can change the flow characteristics of exhaust gas by adjusting the guide vane opening to improve fuel efficiency. One configuration of such a variable geometry turbocharger is disclosed in patent document WO 2006 / 032827 A1.

[0003] Further prior art can be found in document JP S63-159 673 A, which discloses a guide vane, in document DE 10 2012 101 974 A1, which discloses a turbine for an exhaust gas turbocharger, in document DE 10 2008 059 615 A1, which discloses a variable turbine geometry and in document JP 2013-155 640 A, which discloses a variable stator vane mechanism. PRESENTATION OF THE INVENTION

[0004] A guide vane of a variable geometry turbocharger is rotatably disposed within an exhaust passage defined between a shroud surface and a hub surface, with gaps on both sides of the guide vane between each side and the shroud surface or the hub surface. Furthermore, the guide vane is supported by a rotating shaft on at least one of the sides of the shroud surface or the hub surface and is configured to change the guide vane opening degree by rotating about the rotating shaft.

[0005] When the output power of the variable geometry turbocharger is low, the opening degree of the guide vane is small, and the exhaust gas flow into the gaps on both sides of the guide vane, as described above, has a relatively large influence on the performance of the variable geometry turbocharger.

[0006] In this regard, the conventional guide vane disclosed in Patent Document 1 has a flange portion at the end of the guide vane on the rotating shaft side, and the exhaust gas flow into the gap on one side where the rotating shaft and the flange portion are present is poorer than the exhaust gas flow into the gap on the other side. Therefore, the performance of the variable geometry turbocharger may decrease at low power. However, Patent Document 1 does not disclose any findings on improving the exhaust gas flow into the gap around the rotating shaft among the gaps on both sides of the guide vane.

[0007] In view of the above, it is an object of at least one embodiment of the present disclosure to provide a guide vane that can improve exhaust flow around the guide vane in a variable geometry turbocharger.

[0008] The present invention is defined by the guide vane according to claim 1 and the turbocharger according to claim 8.

[0009] (1) A guide vane according to at least one embodiment of the present invention is a guide vane of a variable geometry turbocharger, comprising: a guide vane body rotatably disposed in an exhaust passage defined between a shroud surface and a hub surface; and a flange portion provided on at least one of a shroud-side end surface or a hub-side end surface of the guide vane body and formed around a rotation center of the guide vane body. The flange portion is formed to satisfy the following expression (i) or (ii): R1 <R2 R4 <R3 where R1 is the shortest distance from the rotation center to an outer edge of the flange portion on the trailing edge side and on a suction surface of the guide vane, R2 is the shortest distance from the rotation center to the outer edge of the flange portion on the leading edge side and on the suction surface of the guide vane, R3 is the shortest distance from the rotation center to the outer edge of the flange portion on the leading edge side and on a pressure surface of the guide vane, and R4 is the shortest distance from the rotation center to the outer edge of the flange portion on the trailing edge side and on the pressure surface of the guide vane.

[0010] In the above configuration (1), since R1 is smaller than R2, the exhaust gas flowing from the upstream side of the suction surface and passing near the rotation center easily flows into the gap between the shroud surface or the boss surface and the guide vane where the rotating shaft is located, downstream of the flange portion 50, making it possible to improve the exhaust gas flow around the rotation center. Since R4 is smaller than R3, the exhaust gas flowing into the gap from the suction surface side can smoothly flow out into the exhaust passage on the pressure surface side downstream of the flange portion 50. Since the exhaust gas flow around the flange portion of the guide vane or rotating shaft can be improved, the low-power performance of the variable geometry turbocharger can be improved.

[0011] (2) In some embodiments, in the above configuration (1), the flange portion may include an exhaust passage-side flange surface facing the exhaust passage, and the exhaust passage-side flange surface may include an edge portion formed in a convex arc shape protruding into the exhaust passage.

[0012] With the configuration in which the edge portion of the exhaust passage-side flange surface of the flange portion is formed into a convex arc shape protruding into the exhaust passage, as in the above (2), it is possible to effectively prevent the exhaust gas flowing along the exhaust passage-side flange surface and then into the gap on the rotating shaft side of the guide vane from being separated when passing through the edge portion of the passage-side flange surface. Thus, the generation of turbulence and swirl caused by the separation can be suppressed, so that the exhaust gas flow through the gap can be improved and the low-power performance of the variable geometry turbocharger can be improved.

[0013] (3) In some embodiments in the above configuration (1) or (2), the flange portion may be formed on the hub-side end surface of the vane body.

[0014] With the above configuration (3), it is possible to achieve the effect described in (1) or (2) above in the guide vane having the flange portion on the hub-side end surface of the guide vane body.

[0015] (4) In some embodiments in the above configuration (1) or (2), the flange portion may be formed on the shroud-side end surface of the vane body.

[0016] With the above configuration (4), it is possible to achieve the effect described in (1) or (2) above in the guide vane having the flange portion on the shroud-side end surface of the guide vane body.

[0017] (5) In some embodiments in the above configuration (1) or (2), the flange portion may be formed on the hub-side end surface and the shroud-side end surface of the vane body.

[0018] With the above configuration (5), it is possible to achieve the effect described in (1) or (2) above in the guide vane having the flange portion on the hub-side end surface and the shroud-side end surface of the guide vane body.

[0019] (6) In some embodiments, in any of the above configurations (1) to (5), the flange portion may satisfy the following expression (iii). R3 <R2

[0020] With the above configuration (6), it is possible to efficiently distribute the exhaust gas around the flange portion, for example, when the variable geometry turbocharger is operated with a large difference between the flow rate of the exhaust gas flowing into the suction surface and the flow rate of the exhaust gas flowing into the pressure surface.

[0021] (7) In some embodiments, in any of the above configurations (1) to (5), the flange portion may satisfy the following expression (iv). R2 <R3

[0022] With the above configuration (7), it is possible to efficiently distribute the exhaust gas around the flange portion, for example, when the variable geometry turbocharger is operated with a large difference between the flow rate of the exhaust gas flowing into the suction surface and the flow rate of the exhaust gas flowing into the pressure surface.

[0023] At least one embodiment of the present disclosure provides a guide vane that can improve exhaust flow around the guide vane in a variable geometry turbocharger. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a cross-sectional view of a variable geometry turbocharger turbine including a vane according to a first embodiment of the present disclosure. Fig. 2 is a cross-sectional view along the line II-II in Fig. 1. Fig. 3 is a perspective view showing the shape of the guide vane according to an embodiment, wherein the suction surface is shown as viewed from the rotating shaft side and the leading edge side. Fig. 4 is a perspective view for describing the shape of the guide vane according to an embodiment, showing the state viewed from the guide vane shaft. Fig. 5 is a diagram showing the shape of the guide vane according to an embodiment; (A) is a view from the leading edge side, and (B) is a view from the suction surface side. Fig. 6 is a contour diagram showing the magnitude of entropy on the pressure surface side of the guide vane; (A) shows the guide vane according to an embodiment, and (B) shows the conventional guide vane as a comparison example. Fig. 7 is a contour diagram showing the pressure around the guide vane; (A) shows the guide vane according to an embodiment, and (B) shows the conventional guide vane as a comparative example. Fig. 8 is a contour diagram showing the streamlines around the guide vane; (A) shows the guide vane according to an embodiment, and (B) shows the conventional guide vane as a comparative example. Fig. 9 is a perspective view showing an example of the shape of the guide vane according to another embodiment. Fig. 10 is a perspective view showing an example of the shape of the guide vane according to another embodiment. Fig. 11 is a perspective view showing an example of the shape of the guide vane according to another embodiment. DETAILED DESCRIPTION

[0024] Embodiments of the present invention will now be described in detail with reference to the accompanying drawings. However, the scope of the present invention is not limited to the following embodiments. The dimensions, materials, shapes, relative positions, and the like of components described in the embodiments are intended to be illustrative only and not to limit the scope of the present invention.

[0025] First, a schematic configuration of a variable geometry turbocharger to which a guide vane according to an embodiment of the present disclosure is applied will be described.

[0026] Fig. 1 is a cross-sectional view of a variable geometry turbocharger turbine including a vane according to a first embodiment of the present disclosure. Fig. 2 is a cross-sectional view along the line II-II in Fig. 1.

[0027] As in Fig. 1, a turbine 2 of a variable geometry turbocharger 1 includes a turbine housing 3 having a spiral turbine scroll 4, a turbine wheel 5 rotatably disposed on the radially inner side of the turbine housing 3, and a variable vane mechanism 6 for controlling the flow passage area of ​​the exhaust gas G flowing from the turbine housing 4 to the turbine wheel 5.

[0028] The turbine wheel 5 includes a hub 23 rotatably supported in a bearing housing 7, and a plurality of blades 25 (turbine blades) arranged on the outer periphery of the hub 23 at intervals in the circumferential direction.

[0029] The variable vane mechanism 6 includes a vane 10, a vane mount 13 fixed to the bearing housing 7, and a vane plate 14 arranged to oppose the vane mount 13 at a distance.

[0030] In this disclosure, a separating portion including the vane plate 14 and the turbine casing 3 surrounding the turbine wheel 5 is referred to as a shroud, the surface of the vane plate 14 facing the vane mount 13 is referred to as a shroud surface 41, and the surface of the vane mount 13 facing the vane plate 14 is referred to as a hub surface 43.

[0031] The guide device 10 has a plurality of guide vanes 11 arranged to surround the turbine wheel 5 and a guide vane shaft 12 attached to each guide vane 11. Each guide vane shaft 12 is rotatably supported by the guide vane mount 13. Each guide vane shaft 12 is connected to an actuator (not shown) via a linkage mechanism 15. Each guide vane shaft 12 is rotated by the torque provided by the actuator. As each guide vane shaft 12 rotates, the guide vane 11 also rotates.

[0032] As in Fig. 2, an exhaust passage 16 is formed between adjacent guide vanes 11, 11, through which the exhaust gas G that has passed through the turbine housing 4 flows. Through the exhaust passage 16, a side of the turbine housing 4 on the outer peripheral side has a high pressure due to the exhaust gas G, and a side of the turbine wheel 5 on the inner peripheral side has a low pressure. The exhaust gas G that has passed through the turbine housing 4 flows into the exhaust passage 16 at a certain flow angle. At this time, the pressure at a pressure surface 32 (described later) of the guide vane 11 facing the flow is increased, while the pressure at a suction surface 33 (described later) is low.

[0033] Next, the guide vane 11 according to an embodiment of the present disclosure will be described in detail.

[0034] Fig. 3 is a perspective view showing the shape of the guide vane according to an embodiment, wherein the suction surface is shown as viewed from the rotating shaft side and the leading edge side. Fig. 4 is a perspective view for describing the shape of the guide vane according to an embodiment, showing the state viewed from the guide vane shaft.

[0035] As in Fig. 3, the guide vane 11 according to at least one embodiment of the present invention is the guide vane 11 of the variable geometry turbocharger 1 and includes a guide vane body 31 rotatably disposed in the exhaust passage 16 defined between the shroud surface 41 and the hub surface 43, and a flange portion 50 provided on at least one of the shroud-side end surface 51 or a hub-side end surface of the guide vane body and formed around the rotation center C of the guide vane body 31.

[0036] The guide vane body 31 has a profile defined by the pressure surface 32, the suction surface 33 opposite the pressure surface 32, the leading edge 34, and the trailing edge 35. The guide vane body 31 is rotatably supported in the chord direction between the leading edge 34 and the trailing edge 35 by the guide vane mount 13 via the guide vane shaft 12, which serves as a rotation shaft, in the direction perpendicular to the chord direction and parallel to the leading edge 34 or the trailing edge 35 (i.e., in the width direction of the guide vane body 31).

[0037] The flange portion 50 is generally provided on the hub-side end surface 52 or the shroud-side end surface 51 of the vane body 31 on the side where the link mechanism 15 or the vane shaft 12 is located, and has a function of a lid for preventing exhaust gas G from flowing into the space where the link mechanism 15 is housed.

[0038] For example in Fig. 4, the flange portion 50 of the present disclosure is shaped to satisfy the following expression (i) or (ii): R1 <R2 R4 <R3 where R1 is the shortest distance from the rotation center C to the outer edge 58 of the flange portion 50 on the trailing edge 35 side and on the suction surface 33 of the guide vane 11 (for example, referred to as the first quadrant), R2 is the shortest distance to the outer edge 58 of the flange portion 50 on the leading edge 34 side and on the suction surface 33 (for example, referred to as the second quadrant), R3 is the shortest distance to the outer edge 58 of the flange portion 50 on the leading edge 34 side and on the pressure surface 32 of the guide vane 11 (for example, referred to as the third quadrant), and R4 is the shortest distance to the outer edge 58 of the flange portion 50 on the trailing edge 35 side and on the pressure surface 32 (for example, referred to as the fourth quadrant).

[0039] In other words, in the present disclosure, the flange portion 50 is formed asymmetrically on the leading edge 34 side and the trailing edge 35 side with respect to a plane perpendicular to the chord direction of the vane body 31 and including the axis of the vane shaft 12 (a plane perpendicular to the chord direction of the vane body 31 and passing through the Y-axis), so that the shortest distance to the outer edge 58 of the flange portion 50 on the trailing edge 35 side is smaller than the shortest distance to the outer edge 58 of the flange portion 50 on the leading edge 34 side.

[0040] The flange portion 50 described above may be configured such that, for example, the connection or boundary between the outer edge 58 of the flange portion 50 and the suction surface 33 or the pressure surface 32 on the side of the trailing edge 35 has a smaller distance from the rotation center C than the connection or boundary between the outer edge 58 of the flange portion 50 and the suction surface 33 or the pressure surface 32 on the side of the leading edge 34 (see, for example, R1, R2 in Fig. 9, R3, R4 in Fig. 10, R1, R2 and R3, R4 in Fig. 11).

[0041] However, the flange portion 50 may be configured such that the connection or boundary between the outer edge 58 of the flange portion 50 and the suction surface 33 or the pressure surface 32 on the trailing edge 35 side is at a greater distance from the center of rotation C than the connection or boundary between the outer edge 58 of the flange portion 50 and the suction surface 33 or the pressure surface 32 on the leading edge 34 side. In this case, the flange portion 50 may be configured such that, for example, in the axial view of the guide vane shaft 12, the outer edge 58 on the trailing edge 35 side has a smaller inclination to the chord direction than on the leading edge 34 side (see, for example, Fig. 3, Fig. 4 and Fig. 5(B)).

[0042] Such a flange portion 50 may be configured such that the outer edge 58 is continuous with the suction surface 33 and the pressure surface 32 of the vane body 31 in a smooth curve in the axial view of the vane shaft 12. More specifically, the end portions of the outer edge 58 of the flange portion 50 at the suction surface 33 on the leading edge 34 side and the trailing edge 35 side may be configured such that they each continue to the suction surface 33 with a smooth curve that is concave toward the exhaust passage 16 to which the end portion faces. Furthermore, the end portions of the outer edge 58 of the flange portion 50 on the pressure surface 32 on the front edge 34 side and the rear edge 35 side may be designed to continue to the pressure surface 32 with a smooth curve that is concave in the direction of the exhaust passage 16 to which the end portion faces.

[0043] In the above configuration, since R1 is smaller than R2, the exhaust gas G flowing from the upstream of the suction surface 33 and passing near the rotation center C easily flows into the gap 18 between the shroud surface 41 or the boss surface 43 and the guide vane 11 where the guide vane shaft 12 (rotation shaft) is arranged, downstream of the flange portion 50, so that it is possible to improve the exhaust gas flow G around the rotation center C. Since R4 is smaller than R3, the exhaust gas G flowing into the gap 18 from the suction surface 33 side can smoothly flow out into the exhaust passage 16 on the pressure surface 32 side downstream of the flange portion 50. Since the exhaust gas flow G around the flange portion 50 of the guide vane 11 or the guide vane shaft 12 can be improved, the performance of the variable geometry turbocharger 1 (especially the performance of the variable geometry turbocharger 1 at low power) can be improved.

[0044] Fig. 5 is a diagram showing the shape of the guide vane according to an embodiment; (A) is a view from the leading edge side, and (B) is a view from the suction surface side.

[0045] In some embodiments in the above configuration, for example as in Fig. 5(A) and Fig. As shown in Figure 5(B), the flange portion 50 includes an exhaust passage-side flange surface 55 facing the exhaust passage 16. The exhaust passage-side flange surface 55 may include a flange portion 56 formed in a convex arc shape that protrudes into the exhaust passage 16.

[0046] The edge portion 56 is formed in a convex shape without corners (or rounded corners due to a smooth curved surface), compared to the conventional flange portion, which has a cylindrical or conical shape with a ridge or boundary where the peripheral portion and the bottom portion intersect at a predetermined angle. The edge portion 56 is formed such that, for example, as the distance from the rotation center C increases, the distance from the end surface of the vane body 31 on the side where the vane shaft 12 is located (e.g., the hub-side end surface 52 when the vane shaft 12 is arranged on the hub surface 43 side, and the shroud-side end surface 51 when the vane shaft 12 is arranged on the shroud surface 41 side) progressively decreases.

[0047] The edge portion 56 may be formed on at least a portion of the outer edge 58 of the flange portion 50 or as a uniform, curved surface over the entire circumference of the outer edge 58 of the flange portion 50.

[0048] The curvature of the edge portion 56 on the leading edge 34 side of the flange portion 50 may be the same as or different from the curvature of the edge portion 56 on the trailing edge 35 side. Furthermore, the curvature of the edge portion 56 may be uniform on, for example, the leading edge 34 side or the trailing edge 35 side, or may be partially different at each point, and it can be freely adjusted so that the points are smoothly and continuously formed.

[0049] With reference to the Fig. 6, Fig. 7 and Fig. 8, the effect of the flange portion 50 with the above configuration is described.

[0050] Fig. 6 is a contour diagram showing the magnitude of entropy on the pressure surface side of the guide vane; (A) shows the guide vane according to an embodiment, and (B) shows the conventional guide vane as a comparative example. Fig. 7 is a contour diagram showing the pressure around the guide vane; (A) shows the guide vane according to an embodiment, and (B) shows the conventional guide vane as a comparative example. Fig. 8 is a contour diagram showing the streamlines around the guide vane; (A) shows the guide vane according to an embodiment, and (B) shows the conventional guide vane as a comparative example.

[0051] First, with reference to the Fig. 6(A) and Fig. 6(B), it can be seen that the entropy of the area P1, which is located on the side of the trailing edge 35 of the guide vane shaft 12 on the pressure surface 32 of the Fig. 6(A) of the present disclosure is lower than the entropy of the region P2 located on the trailing edge 35 side of the vane shaft 12 on the thrust surface 32 of the conventional vane shown as a comparative example in Fig. 6(B). The figure shows how much loss occurs in the exhaust gas flow G. The higher the entropy, the greater the loss. Therefore, from the Fig. 6(A) and Fig. 6(B) that the flow loss of the exhaust gas G can be significantly reduced by employing the guide vane 11 of the present disclosure including the flange portion 50.

[0052] Furthermore, with reference to the Fig. 7(A) and Fig. 7(B), it can be seen that the pressure of the area P3, which is located on the side of the trailing edge 35 of the guide vane shaft 12 on the pressure surface 32 of the Fig. 7(A) of the present disclosure is higher than the pressure of the region P4 located on the trailing edge 35 side of the vane shaft 12 on the thrust surface 32 of the conventional vane shown as a comparative example in Fig. 7(B). Therefore, from the Fig. 7(A) and Fig. 7(B) that the pressure loss of the exhaust gas G passing around the flange portion 50 can be significantly reduced by using the guide vane 11 of the present disclosure including the flange portion 50.

[0053] Furthermore, with reference to the Fig. 8(A) and Fig. 8(B), it can be seen that in the area P6 located on the side of the trailing edge 35 of the vane shaft 12 on the thrust surface 32 of the conventional vane shown as a comparative example in Fig. 8(B), there are few (or almost no) streamlines of the exhaust flow G passing through the region P6, so that the shape of the conventional flange portion causes a separation in the exhaust flow G and deteriorates the flow around the flange portion. In contrast, on the Fig. 8(A), effective streamlines are present indicating the exhaust gas flow G through the area P5 located on the trailing edge 35 side of the vane shaft 12. Therefore, from the Fig. 8(A) and Fig. 8(B) that the flow of the exhaust gas G passing around the flange portion 50 can be significantly improved by employing the guide vane 11 of the present disclosure including the flange portion 50.

[0054] Thus, with the configuration in which the edge portion 56 of the exhaust passage-side flange surface 55 of the flange portion 50 is formed into a convex arc shape that protrudes into the exhaust passage 16, it is possible to effectively prevent the exhaust gas G flowing along the exhaust passage-side flange surface 55 and then into the gap 18 on the guide vane shaft 12 serving as the rotation shaft of the guide vane 11 from being separated when passing through the edge portion 56 of the passage-side flange surface 55. In this way, the generation of turbulence and swirl caused by the separation can be suppressed, so that the exhaust gas flow G through the gap 18 can be improved, and the low-power performance of the variable geometry turbocharger 1 can be improved.

[0055] In some embodiments, in one of the above configurations, for example as in Fig. 5(A) and Fig. 5(B), the flange portion 50 may be formed on the hub-side end surface 52 of the vane body 31.

[0056] With this configuration, it is possible to achieve the effect described in the above-described embodiment in the guide vane 11 having the flange portion 50 on the hub-side end surface 52 of the guide vane body 31.

[0057] Furthermore, in some embodiments in any of the above-mentioned configurations, the flange portion 50 may be formed on the shroud-side end surface 51 of the vane body 31. The effect of disposing the flange portion 50 on the shroud-side end surface 51 on the flow of the exhaust gas G in the exhaust passage 16 is the same as when the flange portion 50 is disposed on the hub-side end surface 52 as described above, and a description is therefore omitted.

[0058] With the above configuration in which the flange portion 50 is arranged on the shroud-side end surface 51 of the vane body 31, it is possible to achieve the effect described in the above-described embodiment in the vane 11 having the flange portion 50 on the shroud-side end surface 51 of the vane body 31.

[0059] Fig. 9 is a perspective view showing an example of the shape of the guide vane according to another embodiment. Fig. 10 is a perspective view showing an example of the shape of the guide vane according to another embodiment.

[0060] In some embodiments, in any of the above configurations, for example as shown in the Fig. 9 and Fig. 10, the flange portion 50 may be formed on the hub-side end surface 52 and the shroud-side end surface 51 of the vane body 31.

[0061] In other words, the flange portion 50 may be formed on each side of the vane body 31 in the width direction.

[0062] With the above configuration in which the flange portion 50 is arranged on each side of the vane body 31, it is possible to achieve the effect described in the above-described embodiment in the vane having the flange portion on the hub-side end surface 52 and the shroud-side end surface 51 of the vane body 31.

[0063] In some embodiments, in any of the above configurations, for example as in Fig. 9, the flange portion 50 can satisfy the following expression (iii). R2>R3

[0064] In particular, according to some embodiments, the flange portion 50 may be configured such that the shortest distance R2 to the outer edge 58 of the flange portion 50 on the side of the leading edge 34 and on the suction surface 33 (e.g., the second quadrant) is greater than the shortest distance R3 to the outer edge 58 of the flange portion 50 on the side of the leading edge 34 and on the pressure surface 32 of the guide vane 11 (e.g., the third quadrant).

[0065] In the Fig. 9, the flange portion 50 satisfying the expression (iii) is arranged on both the shell-side end surface 51 and the hub-side end surface 52, but the flange portion 50 satisfying the expression (iii) may be arranged on the shell-side end surface 51 or the hub-side end surface 52.

[0066] Thus, with the configuration in which the shortest distance R2 to the outer edge 58 of the flange portion 50 on the leading edge 34 side and on the suction surface 33 is greater than the shortest distance R3 to the outer edge 58 of the flange portion 50 on the leading edge 34 side and on the pressure surface 32 of the guide vane 11 (R2>R3), it is possible to efficiently distribute the exhaust gas G around the flange portion 50, for example, when the variable geometry turbocharger 1 is operated with a large difference between the flow rate of the exhaust gas G flowing into the suction surface 33 and the flow rate of the exhaust gas G flowing into the pressure surface 32 (for example, when the inflow amount of the exhaust gas G on the suction surface 33 side is greater than the inflow amount of the exhaust gas G on the pressure surface 32 side).

[0067] In some embodiments, in any of the above configurations, for example as shown in the Fig. 10 to 11, the flange portion 50 can satisfy the following expression (iv). R2 <R3

[0068] In particular, according to some embodiments, the flange portion 50 may be configured such that the shortest distance R2 to the outer edge 58 of the flange portion 50 on the side of the leading edge 34 and on the suction surface 33 (e.g., the second quadrant) is smaller than the shortest distance R3 to the outer edge 58 of the flange portion 50 on the side of the leading edge 34 and on the pressure surface 32 of the guide vane 11 (e.g., the third quadrant).

[0069] For example, the flange portion 50, as shown in Fig. 10, both on the casing-side end surface 51 and on the hub-side end surface 52. Alternatively, the flange portion 50, as in the example of Fig.11, may be arranged on the casing-side end surface 51 or the hub-side end surface 52.

[0070] Thus, with the configuration in which the shortest distance R2 to the outer edge 58 of the flange portion 50 on the side of the leading edge 34 and on the suction surface 33 is smaller than the shortest distance R3 to the outer edge 58 of the flange portion 50 on the side of the leading edge 34 and on the pressure surface 32 of the guide vane 11 (R2 <R3), möglich, das Abgas G effizient um den Flanschabschnitt 50 zu verteilen, zum Beispiel, wenn der Turbolader 1 mit variabler Geometrie mit einer großen Differenz zwischen der Strömungsrate des Abgases G, das in die Saugfläche 33 strömt, und der Strömungsrate des Abgases G, das in die Druckfläche 32 strömt, betrieben wird (zum Beispiel, wenn die einströmende Menge des Abgases G auf der Seite der Druckfläche 32 größer ist als die einströmende Menge des Abgases G auf der Seite der Saugfläche 33).

[0071] At least one embodiment of the present disclosure provides the guide vane 11 that can improve the exhaust flow G around the guide vane 11 in the variable geometry turbocharger 1. List of reference symbols 1 variable geometry turbocharger 2 turbines 3 Turbine casing (sheathing) 4 turbine housings 5 Turbine wheel (turbine rotor) 6 Variable vane mechanism 7 bearing housing 10 Guidance device 11 Guide vane 12 guide vane shaft (rotation shaft) 13 Guide vane mounting 14 Guide vane plate 15 Connecting mechanism 16 Exhaust passage 18 gap 23 Hub 25 turbine blades 31 guide vane body 32 printing area 33 suction surface 34 leading edge 35 trailing edge 41 Sheathing area 43 hub surface 50 flange section 51 Sheath-side end face 52 Hub-side end face 55 Exhaust passage side flange surface 56 edge section 58 outer edge L Chord length (guide vane body) G exhaust C Center of rotation

Claims

[1] Guide vane (11) of a variable geometry turbocharger (1), comprising: a vane body (31) rotatably disposed in an exhaust passage (16) defined between a shroud surface (41) and a hub surface (43); and a flange portion (50) provided on at least one of a shroud-side end surface (51) or a hub-side end surface (52) of the vane body (31) and formed around a rotation center (C) of the vane body (31), wherein the flange portion (50) is formed to satisfy the following expression (i) or (ii): R1 <R2 R4 <R3 where R1 is the shortest distance from the rotation center (C) to an outer edge (58) of the flange portion (50) on the trailing edge side and on a suction surface (33) of the guide vane (11), R2 is the shortest distance from the rotation center (C) to the outer edge of the flange portion (50) on the leading edge side and on the suction surface (33) of the guide vane (11), R3 is the shortest distance from the rotation center (C) to the outer edge of the flange portion (50) on the leading edge side and on a pressure surface (32) of the guide vane (11), and R4 is the shortest distance from the rotation center (C) to the outer edge of the flange portion (50) on the trailing edge side and on the pressure surface (32) of the guide vane (11). [2] Guide vane (11) according to claim 1, wherein the flange portion (50) has an exhaust gas passage-side flange surface (55) facing the exhaust gas passage (16), and the exhaust passage-side flange surface (55) has an edge portion (56) formed in a convex arc shape projecting into the exhaust passage (16). [3] Guide vane (11) according to claim 1 or 2, wherein the flange portion (50) is formed on the hub-side end surface (52) of the guide vane body (31). [4] A guide vane (11) according to claim 1 or 2, wherein the flange portion (50) is formed on the shroud-side end surface (51) of the guide vane body (31). [5] A guide vane (11) according to claim 1 or 2, wherein the flange portion (50) is formed on the hub-side end surface (52) and the shroud-side end surface (51) of the guide vane body (31). [6] A guide vane (11) according to any one of claims 1 to 5, wherein the flange portion (50) satisfies the following expression (iii) R3 <R2 [7] A guide vane (11) according to any one of claims 1 to 5, wherein the flange portion (50) satisfies the following expression (iv) R2 <R3 [8] Variable geometry turbocharger (1), comprising: a turbine (2), and a guide vane (11) according to one of claims 1 to 7, wherein the guide vane body (31) is rotatably arranged in an exhaust passage (16) of the turbine (2) which is defined between a shroud surface (41) and a hub surface (43).

Images