Variable nozzle device and variable geometry turbocharger

Abstract

Provided is a variable nozzle device for a variable geometry turbocharger, said variable nozzle device comprising a drive ring pressing part that is provided to a first vane lever and that is configured to change the distance between an inner peripheral surface of a drive ring and the rotation axis line of the first vane lever by pressing and displacing the drive ring in the radial direction of the drive ring when the first vane lever rotates.

Description

[Technical field]

[0001] The present disclosure relates to a variable nozzle device and a variable geometry turbocharger. [Background technology]

[0002] Patent Document 1 discloses a variable nozzle device for a variable geometry turbocharger (VG turbocharger), which is configured to adjust the flow path area of ​​an exhaust gas flow path for directing exhaust gas from a turbine scroll flow path to a turbine wheel by changing the blade angle of a variable nozzle vane.

[0003] A typical variable geometry turbocharger employs a link mechanism for transmitting the driving force of an electric actuator to the variable nozzle vanes, which are spaced apart in the circumferential direction, in order to simultaneously open and close the variable nozzle vanes. To achieve a smaller and lighter turbocharger, it is desirable for the contact force of each part of the link mechanism to be smaller. However, because the turbocharger turbine is used in a high-temperature environment, it is necessary to ensure a distance between the high-temperature parts in the link mechanism and the actuator, and the increase in friction parts tends to increase the driving force required for the actuator. The increase in the driving force required for the actuator causes the actuator to become larger, so measures are needed. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2019 / 090018 Summary of the Invention [Problem to be solved by the invention]

[0005] A typical variable nozzle device in a variable geometry turbocharger includes a first annular member that rotatably supports a variable nozzle vane, a second annular member that forms an exhaust gas flow passage between the first annular member and the second annular member, a vane lever that is provided on the opposite side of the first annular member from the exhaust gas flow passage and connects to the shaft of the variable nozzle vane, and a drive ring that engages with the vane lever and is configured to rotate the vane lever around the rotation axis of the variable nozzle vane.

[0006] In such a variable nozzle device, as shown in FIG. 21, when a driving force for rotating the drive ring is transmitted to the drive ring (position A on the drive ring in the example shown in the figure), the drive ring is displaced by the driving force. As a result, the inner circumferential surface of the drive ring comes into contact with the first annular member at a position (position B in the example shown in the figure) on the opposite side of the center of the drive ring to the direction in which the drive ring is displaced, and presses the contact portion, increasing the frictional force between the drive ring and the first annular member. In this case, the driving force required for the actuator to rotate the drive ring increases, which may lead to an increase in the size of the actuator. Patent Document 1 does not disclose any knowledge for solving such a problem.

[0007] In view of the above circumstances, at least one embodiment of the present disclosure aims to provide a variable nozzle device capable of suppressing an increase in the driving force for rotating a drive ring, and a variable geometry turbocharger including the same. [Means for solving the problem]

[0008] In order to achieve the above object, a variable nozzle device according to at least one embodiment of the present disclosure includes: A variable nozzle device for a variable geometry turbocharger, comprising: A first annular member; a second annular member provided opposite to the first annular member and defining, between the first annular member and the second annular member, an exhaust gas passage for guiding exhaust gas from a scroll passage formed on an outer circumferential side of a turbine wheel of the turbocharger to the turbine wheel; A rotatable variable nozzle vane provided in the exhaust gas flow passage; A first vane lever connected to a shaft portion of the variable nozzle vane; a drive ring configured to engage with the first vane lever and rotate the first vane lever about a rotation axis of the shaft portion; a drive ring pressing portion provided on the first vane lever and configured to change a distance between an inner peripheral surface of the drive ring and a rotation axis of the first vane lever by pressing and displacing the drive ring in a radial direction of the drive ring when the first vane lever rotates; Equipped with.

[0009] In order to achieve the above object, a variable geometry turbocharger according to at least one embodiment of the present disclosure includes: The variable nozzle device, The turbine wheel; a casing that houses the turbine wheel; Equipped with. Effect of the Invention

[0010] According to at least one embodiment of the present disclosure, there is provided a variable nozzle device capable of suppressing an increase in the driving force for rotating a drive ring, and a variable geometry turbocharger including the same. [Brief description of the drawings]

[0011] [Figure 1] 1 is a schematic cross-sectional view showing a part of a cross section along a rotation axis of a variable geometry turbocharger according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a view of the variable nozzle device as viewed from the bearing casing side (compressor side) along the axial direction of the turbine wheel. [Figure 3A] FIG. 3 is a diagram showing a part of the example of the variable nozzle device shown in FIGS. 1 and 2, as viewed from the opposite side to the exhaust gas flow passage in the axial direction of the drive ring. [Figure 3B]1 is a diagram showing a portion of a cross section taken along the axial direction of a drive ring in a variable nozzle device. [Figure 4] 4 is an axial view showing a schematic diagram of the positional relationship between each part of the vane lever and a part of the inner peripheral surface of the drive ring (the surface of the drive ring that abuts against the lifting pin) when the drive ring is not lifted by the lifting pin. FIG. [Figure 5A] 3 is a diagram showing a part of another example of the variable nozzle device shown in FIGS. 1 and 2, as viewed from the opposite side to the exhaust gas flow passage in the axial direction of the drive ring. FIG. [Figure 5B] 1 is a diagram showing a portion of a cross section taken along the axial direction of a drive ring in a variable nozzle device. [Figure 6] 11A and 11B are diagrams illustrating examples of the shapes of the lifting pins and the protrusions in a cross section perpendicular to the axial direction of the drive ring. [Figure 7] 13 is a diagram showing another example of the shape of the lifting pin and the protrusion in a cross section perpendicular to the axial direction of the drive ring. FIG. [Figure 8] 13 is a diagram showing yet another example of the shapes of the lifting pins and the protrusions in a cross section perpendicular to the axial direction of the drive ring. FIG. [Figure 9] 13 is a diagram showing yet another example of the shapes of the lifting pins and the protrusions in a cross section perpendicular to the axial direction of the drive ring. FIG. [Figure 10A] 3 is a diagram showing a part of still another example of the variable nozzle device shown in FIGS. 1 and 2, as viewed from the opposite side to the exhaust gas flow passage in the axial direction of the drive ring. FIG. [Figure 10B] 1 is a diagram showing a portion of a cross section taken along the axial direction of a drive ring in a variable nozzle device. [Figure 11] 13 is a diagram showing the relationship between the opening degree of the variable nozzle vanes and the drive torque required of the actuator to rotate the drive ring in a case where a lift pin is not provided in the variable nozzle device. FIG. [Figure 12] FIG. 13 is a diagram showing an example of a preferred arrangement of lifting pins in the circumferential direction of the drive ring. [Figure 13] 1 is an axial view showing a schematic diagram of the positional relationship between each part of the first pin-type vane lever and the inner peripheral surface of the drive ring (the surface of the drive ring that abuts against the lifting pin) when the drive ring is not lifted by the lifting pin. [Figure 14] 1 is an axial view showing a schematic diagram of the positional relationship between each part of the second pin-type vane lever and the inner peripheral surface of the drive ring (the surface of the drive ring that abuts against the lifting pin) when the drive ring is not lifted by the lifting pin. FIG. [Figure 15] FIG. 13 is a diagram showing another example of a preferable arrangement of lifting pins in the circumferential direction of the drive ring. [Figure 16] 1 is an axial view showing the positional relationship between each part of the third pin-type vane lever and the inner peripheral surface of the drive ring (the surface of the drive ring that abuts against the lifting pin) when the drive ring is not lifted by the lifting pin. FIG. [Figure 17] FIG. 11 is a view showing a variable nozzle device according to another embodiment, as viewed from the bearing casing side (compressor side) along the axial direction of the turbine wheel. [Figure 18] FIG. 11 is a view showing a variable nozzle device according to another embodiment, as viewed from the bearing casing side (compressor side) along the axial direction of the turbine wheel. [Figure 19] FIG. 10C is a cross-sectional view showing a modified example of the variable nozzle device shown in FIG. 10B. [Figure 20] 13 is a diagram showing another example of the configuration of a pin-equipped vane lever, showing a part of a variable nozzle device viewed from the opposite side to the exhaust gas flow passage in the axial direction of the drive ring. FIG. [Figure 21] 6A and 6B are diagrams for explaining the frictional force between the inner circumferential surface of the drive ring and the first annular member when the drive ring is driven. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, some embodiments of the present disclosure will be described with reference to the accompanying drawings. However, the dimensions, materials, shapes, relative arrangements, etc. of components described as the embodiments or shown in the drawings are merely illustrative examples and are not intended to limit the scope of the invention. For example, expressions expressing relative or absolute configuration, such as "in a certain direction," "along a certain direction," "parallel," "orthogonal," "center," "concentric," or "coaxial," not only strictly express such a configuration, but also express a state in which there is a relative displacement with a tolerance or an angle or distance to the extent that the same function is obtained. For example, expressions indicating that things are in an equal state, such as "identical," "equal," and "homogeneous," not only indicate a state of strict equality, but also indicate a state in which there is a tolerance or a difference to the extent that the same function is obtained. For example, expressions describing shapes such as a rectangular shape or a cylindrical shape do not only refer to rectangular shapes, cylindrical shapes, etc. in the strict geometric sense, but also refer to shapes that include uneven portions, chamfered portions, etc., to the extent that the same effect is obtained. On the other hand, the expressions "comprise," "include," "have," "includes," or "have" of one element are not exclusive expressions excluding the presence of other elements.

[0013] (Variable Geometry Turbocharger) FIG. 1 is a schematic cross-sectional view showing a part of a cross section along a rotation axis O of a variable geometry turbocharger 100 according to one embodiment. Hereinafter, the variable geometry turbocharger 100 will be simply referred to as turbocharger 100.

[0014] The turbocharger 100 includes a turbine wheel 2 arranged coaxially with a compressor (not shown), a turbine casing 4 that houses the turbine wheel 2, a bearing casing 6 that houses a bearing (not shown) that rotatably supports the turbine wheel 2, and a variable nozzle device 8 provided between the turbine casing 4 and the bearing casing 6.

[0015] A scroll passage 10 is formed on the outer periphery of the turbine wheel 2 in the turbine casing 4, and exhaust gas from an engine (not shown) passes through the scroll passage 10 and is then supplied to the turbine wheel 2 via a variable nozzle device 8.

[0016] (Variable nozzle device) FIG. 2 is a view of the variable nozzle device 8 as viewed from the bearing casing 6 side (compressor side) along the axial direction of the turbine wheel 2. As shown in FIG. 1 or 2, the variable nozzle device 8 includes a first annular member 12 (nozzle mount), a second annular member 14 (nozzle plate), a plurality of variable nozzle vanes 16, a plurality of vane levers 18, and a drive ring 20.

[0017] For example, as shown in FIG. 1, the first annular member 12 is an annular plate provided on the outer periphery of the turbine wheel 2 centered on the rotation axis O of the turbine wheel 2, and rotatably supports a plurality of variable nozzle vanes 16. The first annular member 12 is provided with a plurality of support holes 30 (through holes) penetrating the first annular member 12 in the axial direction at intervals in the circumferential direction of the first annular member 12. The plurality of support holes 30 are provided in one-to-one correspondence with the plurality of variable nozzle vanes 16, and each of the support holes 30 rotatably supports the shaft portion 16a (shaft) of the corresponding variable nozzle vane 16. The first annular member 12 is fixed to at least one of the turbine casing 4 and the bearing casing 6. The first annular member 12 includes a protruding portion 13 protruding in the axial direction of the first annular member 12 from a surface 12a on the opposite side to the exhaust gas passage 24. The protrusion 13 is located on the inner circumferential side of the drive ring 20 , and an outer surface 13 a of the protrusion 13 in the radial direction of the first annular member 12 faces an inner circumferential surface 20 a of the drive ring 20 .

[0018] The second annular member 14 is an annular plate provided on the outer circumferential side of the turbine wheel 2 centered on the rotation axis O of the turbine wheel 2, and is provided opposite the first annular member 12. Between the second annular member 14 and the first annular member 12, an annular exhaust gas passage 24 for guiding exhaust gas from the scroll passage 10 to the turbine wheel 2 is formed. The first annular member 12 and the second annular member are connected by a plurality of support pins (not shown).

[0019] The multiple variable nozzle vanes 16 are disposed at intervals in the circumferential direction of the first annular member 12 in the exhaust gas flow passage 24 between the first annular member 12 and the second annular member 14, and are rotatably supported in multiple support holes 30 in the first annular member 12. The variable nozzle device 8 is configured to adjust the flow passage area of ​​the exhaust gas flow passage 24 by changing the blade angle of the multiple variable nozzle vanes 16.

[0020] As shown in FIG. 1 or FIG. 2, the vane levers 18 are provided at intervals in the circumferential direction of the drive ring 20 on the opposite side of the exhaust gas flow passage 24 across the first annular member 12. The vane levers 18 are provided in one-to-one correspondence with the variable nozzle vanes 16. Each of the vane levers 18 includes a lever body 18a and an engaging protrusion 18b. The lever body 18a is connected to the shaft 16a of the corresponding variable nozzle vane 16 at one end side of the lever body 18a and extends along the radial direction. The engaging protrusion 18b protrudes from the lever body 18a toward the first annular member 12 in the axial direction of the drive ring 20 on the outer side in the radial direction of the drive ring 20 than the shaft 16a of the corresponding variable nozzle vane 16, and engages with a notch 22a of the drive ring 20, which will be described later.

[0021] The drive ring 20 is an annular plate provided around the rotation axis O of the turbine wheel 2, and is disposed between the first annular member 12 and the vane levers 18 in the axial direction of the turbine wheel 2. The drive ring 20 is configured to engage with each of the vane levers 18 and rotate each of the vane levers 18 around the rotation axis C of the shaft portion 16a of the corresponding variable nozzle vane 16. In the illustrated example, the outer peripheral edge portion 22 of the drive ring 20 is provided with a plurality of cutout portions 22a spaced apart in the circumferential direction of the drive ring 20, and the cutout portions 22a are formed in one-to-one correspondence with the plurality of engaging protrusions 18b. The engaging protrusions 18b of the vane levers 18 are disposed inside the corresponding cutout portions 22a and engage with the cutout portions 22a.

[0022] When the drive ring 20 rotates, the engaging protrusion 18b engaging with the notch 22a moves in the rotational direction of the drive ring 20, causing the vane lever 18 to rotate around the rotation axis C of the shaft portion 16a of the variable nozzle vane 16. A pin 23 (see FIG. 2) is provided on one surface of the drive ring 20 in the axial direction of the drive ring 20 (the surface of the drive ring 20 opposite the exhaust gas flow path 24 in the illustrated example) as a driving force receiving portion for receiving a driving force for rotating the drive ring 20 from an actuator (not shown). The pin 23 protrudes in the axial direction from the one surface of the drive ring 20 in the axial direction toward the opposite side to the exhaust gas flow path 24.

[0023] In this variable nozzle device 8, the drive ring 20 is rotationally driven by a driving force transmitted to the pin 23 from an actuator (not shown) included in the variable geometry turbocharger 100 via a link mechanism (not shown). When the drive ring 20 rotates, each of the multiple vane levers 18 engaged with the drive ring 20 rotates the shaft portion 16a of the corresponding variable nozzle vane 16, and as a result, the multiple variable nozzle vanes 16 rotate simultaneously and the blade angles of the multiple variable nozzle vanes 16 change uniformly. In this way, the blade angles of the multiple variable nozzle vanes 16 are simultaneously adjusted to a common blade angle by the drive ring 20.

[0024] Fig. 3A is a diagram showing a portion of a variable nozzle device 8A, which is an example of the variable nozzle device 8 shown in Fig. 1 and Fig. 2, as viewed from the opposite side to the exhaust gas flow path 24 in the axial direction of the drive ring 20. Fig. 3B is a diagram showing a portion of a cross section of the variable nozzle device 8A taken along the axial direction of the drive ring 20.

[0025] In some embodiments, as shown in, for example, FIG. 3A and FIG. 3B, the vane levers 18 of the variable nozzle device 8A include a vane lever 18 provided with a lifting pin 25 (drive ring pressing portion) that can abut against the drive ring 20. Hereinafter, the vane lever 18 provided with the lifting pin 25 will be referred to as a pinned vane lever 18A. The lifting pin 25 protrudes in the axial direction of the drive ring 20 from a surface 18c on the drive ring 20 side of the lever body portion 18a of the pinned vane lever 18A, and is configured to lift the drive ring 20 by the rotation of the pinned vane lever 18A. In the configuration shown in FIG. 3A and FIG. 3B, the lifting pin 25 abuts against an inner peripheral surface 20a of the drive ring 20 in the radial direction of the drive ring 20, and is configured to lift the drive ring 20 to the outside in the radial direction of the drive ring 20 via the inner peripheral surface 20a of the drive ring 20 by the rotation of the pinned vane lever 18A. In this specification, "lifting the drive ring 20" means pressing and displacing the drive ring 20 in the radial direction of the drive ring 20, thereby moving the inner surface 20a of the drive ring 20 away from the rotation axis C of the vane lever 18A.

[0026] The lifting effect of the lifting pins 25 on the drive ring 20 will be described below with reference to FIG. Figure 4 is an axial view showing a schematic diagram of the positional relationship between each part of the vane lever 18 and a part of the inner surface 20a of the drive ring 20 (the surface of the drive ring 20 that abuts against the lifting pin 25) when the drive ring 20 is not lifted by the lifting pin 25.

[0027] As shown in Figure 4, if the position on the outer circumferential surface 25a of the lifting pin 25 farthest from the rotation axis C of the pinned vane lever 18A is P1, the distance between position P1 and the rotation axis C of the pinned vane lever 18A is r1, and the distance between the inner circumferential surface 20a of the drive ring 20 and the rotation axis C of the pinned vane lever 18A when the drive ring 20 is not lifted by the lifting pin 25 is r0, the lifting pin 25 is positioned so that r1>r0 is satisfied. In Figure 4, the trajectory of position P1 when the pinned vane lever 18A is rotated around the rotation axis C of the pinned vane lever 18A is shown by a dotted circle, and the drive ring 20 is lifted by the lifting pin 25 when the above-mentioned trajectory of the lifting pin 25 exceeds the position of the inner surface 20a of the drive ring 20 when the drive ring 20 is not lifted by the lifting pin 25 to the radial outside of the shaft portion 16a (when the angle of the pinned vane lever 18A is within the range of angle θ in Figure 4).

[0028] In this way, when the pinned vane lever 18A rotates, the lifting pin 25 presses and displaces the drive ring 20 in the radial direction of the drive ring 20, thereby changing the distance between the inner circumferential surface 20a of the drive ring 20 and the rotation axis C of the pinned vane lever 18A. Therefore, the distance between the inner circumferential surface 20a of the drive ring 20 and the rotation axis C of the pinned vane lever 18A changes between r0 and r1 depending on the opening degree of the variable nozzle vane 16.

[0029] Therefore, by arranging the lifting pin 25 so that the distance between the inner circumferential surface 20a of the drive ring 20 and the rotation axis C of the pinned vane lever 18A becomes large at the nozzle opening degree where the driving force for rotating the drive ring 20 is likely to be large, it is possible to reduce the frictional force between the inner circumferential surface 20a of the drive ring and the first annular member 12 at the nozzle opening degree with a simple configuration. This makes it possible to suppress an increase in the driving force for rotating the drive ring 20 and suppress an increase in the size of the actuator for rotating the drive ring 20.

[0030] In addition, because the lifting pins 25 press the inner peripheral surface 20a of the drive ring 20 in the radial direction of the drive ring 20 to lift the drive ring 20, there is no need to provide structures such as the convex portions 26 and concave portions 32 described below, which is advantageous in terms of strength compared to variable nozzle devices 8B and 8C described below. In addition, the contact area between the drive ring 20 and the lifting pins 25 can be made wider, which is advantageous in terms of wear resistance.

[0031] Figure 5A is a diagram showing a part of a variable nozzle device 8B, which is another example of the variable nozzle device 8 shown in Figures 1 and 2, viewed from the opposite side to exhaust gas flow path 24 in the axial direction of drive ring 20. Figure 5B is a diagram showing a part of a cross section of variable nozzle device 8B taken along the axial direction. In variable nozzle device 8B shown in Figures 5A and 5B, reference symbols that are common to the components shown in Figures 3A and 3B indicate the same components as those shown in Figures 3A and 3B unless otherwise specified, and descriptions thereof will be omitted.

[0032] 5A and 5B, the drive ring 20 includes a protrusion 26 that protrudes in the axial direction of the drive ring 20 from a surface 20c of the drive ring 20 facing the pinned vane lever (the surface opposite the exhaust gas flow path 24) at a position outside the lifting pin 25 in the radial direction of the drive ring 20. The lifting pin 25 abuts against the protrusion 26 in the radial direction of the drive ring 20, and is configured to lift the drive ring 20 outward in the radial direction of the drive ring 20 via the protrusion 26 when the pinned vane lever 18A rotates.

[0033] Therefore, by arranging the lifting pin 25 so that the distance between the inner circumferential surface 20a of the drive ring 20 and the rotation axis C of the pinned vane lever 18A becomes large at the nozzle opening degree where the driving force for rotating the drive ring 20 is likely to be large, it is possible to reduce the frictional force between the inner circumferential surface 20a of the drive ring and the first annular member 12 at that nozzle opening degree with a simple configuration. This makes it possible to suppress an increase in the driving force for rotating the drive ring 20 with a simple configuration and to suppress an increase in the size of the actuator for rotating the drive ring 20.

[0034] Furthermore, since the convex portion 26 can be formed radially outward of the drive ring 20 rather than the inner surface 20a of the drive ring 20, the rotation radius of the lifting pin 25 (the distance between the lifting pin 25 and the rotation axis C) can be made larger than in the above-mentioned variable nozzle device 8A, and the frictional force between the drive ring 20 and the first annular member 12 can be reduced over a wide range in the circumferential direction of the drive ring 20.

[0035] 5A, in a cross section perpendicular to the axial direction of drive ring 20, lifting pin 25 is formed in a circular shape, and protrusion 26 is formed in a quadrangular shape (rectangular in the illustrated example). In addition, in a cross section perpendicular to the axial direction, the length of protrusion 26 in a direction perpendicular to the radial direction of drive ring 20 is greater than the width of protrusion 26 in the radial direction of drive ring 20, and is greater than the diameter of lifting pin 25. However, the shapes of lifting pin 25 and protrusion 26 are not limited thereto, and may be a quadrangular, polygonal, or sector shape, or may include a circular arc, in a cross section perpendicular to the axial direction of drive ring 20, as shown in FIGS. 6 to 9.

[0036] In the example shown in FIG. 6, in a cross section perpendicular to the axial direction of the drive ring 20, the lifting pin 25 is formed in a circular shape, and the radially inner surface 26a of the protrusion 26 of the drive ring 20 is formed by a concave curve 28. In addition, in a cross section perpendicular to the axial direction of the drive ring 20, the concave curve 28 is an arc, and the radius of curvature of the concave curve 28 is larger than the radius of curvature of the outer circumferential surface 25a of the lifting pin 25. In addition, in a cross section perpendicular to the axial direction of the drive ring 20, the length of the protrusion 26 in a direction perpendicular to the radial direction of the drive ring 20 is longer than the width of the protrusion 26 in the radial direction of the drive ring 20, and is larger than the diameter of the lifting pin 25. In this way, by forming the radially inner surface 26a of the protrusion 26 of the drive ring 20 by the concave curve 28, the frictional force between the drive ring 20 and the first annular member 12 can be reduced over a wide range in the circumferential direction of the drive ring 20, compared to the case where the surface 26a is formed by a flat surface.

[0037] In the example shown in FIG. 7, in a cross section perpendicular to the axial direction of the drive ring 20, the lifting pin 25 is formed in a polygonal shape (a regular octagon in the illustrated example), and the protrusion 26 is formed in a quadrangular shape (rectangle). In addition, the inner surface 26a of the protrusion 26 in the radial direction of the drive ring 20 is formed by a flat surface. In addition, in a cross section perpendicular to the axial direction of the drive ring 20, the length of the protrusion 26 in the direction perpendicular to the radial direction of the drive ring 20 is larger than the width of the protrusion 26 in the radial direction of the drive ring 20, and is larger than the width of the lifting pin 25 in the direction perpendicular to the radial direction of the drive ring 20. According to the configuration shown in FIG. 7, the lifting effect of lifting the protrusion 26 by the lifting pin 25 can be obtained over a wide range in the circumferential direction.

[0038] In the example shown in Figure 8, in a cross section perpendicular to the axial direction of the drive ring 20, the lifting pin 25 is formed in a circular shape, and the radial inner surface 26a of the drive ring 20 at the convex portion 26 is formed in a concave shape (a shape formed by connecting multiple straight lines along a circular arc).

[0039] 9, in a cross section perpendicular to the axial direction of the drive ring 20, the lifting pin 25 is formed in a semicircle (fan shape), and the protrusion 26 is formed in a quadrangle (rectangle in the illustrated example). Furthermore, the inner surface 26a of the protrusion 26 in the radial direction of the drive ring 20 is formed by a flat surface. In a cross section perpendicular to the axial direction of the drive ring 20, the lifting pin 25 is disposed so that the arc constituting the semicircle abuts against the inner surface 26a of the protrusion 26 in the radial direction of the drive ring 20.

[0040] As in some of the examples above, when, in a cross section perpendicular to the axial direction of the drive ring 20, the radially inner surface 26a of the drive ring 20 at the convex portion 26 is formed by a concave curve (e.g., a circular arc) or a plane, and the lifting pin 25 is formed by a polygon or the like, the range in which the lifting effect of the lifting pin 25 to lift the convex portion 26 can be set arbitrarily.

[0041] Figure 10A is a diagram showing a part of a variable nozzle device 8C, which is yet another example of the variable nozzle device 8 shown in Figures 1 and 2, viewed from the opposite side to exhaust gas flow path 24 in the axial direction of drive ring 20. Figure 10B is a diagram showing a part of a cross section of variable nozzle device 8C taken along the axial direction of drive ring 20. In variable nozzle device 8C shown in Figures 10A and 10B, reference numerals that are common to the components shown in Figures 3A and 3B indicate the same components as those shown in Figures 3A and 3B unless otherwise specified, and descriptions thereof will be omitted.

[0042] In Fig. 10A and Fig. 10B, the surface 20c of the drive ring 20 on the pinned vane lever 18A side (the surface of the drive ring 20 opposite to the exhaust gas flow path 24) includes a recess 32. The tip 25b of the lifting pin 25 is located inside the recess 32. The lifting pin 25 abuts against a surface 32a1 of the inner surface 32a of the recess 32 facing the radial inside of the drive ring 20, and is configured to lift the drive ring 20 via the surface 32a1 of the recess 32 by the rotation of the pinned vane lever 18A. In the illustrated example, in a cross section perpendicular to the axial direction of the drive ring 20, the recess 32 is formed in a fan shape, and the lifting pin 25 is formed in a circular shape. In addition, in a cross section perpendicular to the axial direction of the drive ring 20, the length of the arc constituting the surface 32a1 is greater than the diameter of the lifting pin 25 and greater than the width of the recess 32 in the radial direction of the drive ring 20.

[0043] In the nozzle device 8C as well, by arranging the lifting pin 25 so that the distance between the inner circumferential surface 20a of the drive ring 20 and the rotation axis C of the pinned vane lever 18A becomes large at the nozzle opening degree where the driving force for rotating the drive ring 20 tends to be large, it is possible to reduce the frictional force between the inner circumferential surface 20a of the drive ring and the first annular member 12 at the nozzle opening degree with a simple configuration. This makes it possible to suppress an increase in the driving force for rotating the drive ring 20 with a simple configuration and to suppress an increase in the size of the actuator for rotating the drive ring 20.

[0044] Furthermore, since the recesses 32 can be formed radially outward of the inner circumferential surface 20a of the drive ring 20, the rotation radius of the lifting pins 25 (the distance between the lifting pins 25 and the rotation axis C) can be made larger than in the variable nozzle device 8A, and the frictional force between the drive ring 20 and the first annular member 12 can be reduced over a wide range in the circumferential direction of the drive ring 20. Furthermore, since the contact range between the lifting pins 25 and the drive ring 20 can be made wider than in the variable nozzle device 8B, this is advantageous in terms of wear resistance.

[0045] Here, a preferred arrangement of the pinned vane lever 18A in the variable nozzle device 8 (8A to 8C) will be described.

[0046] 11 is a diagram showing the relationship between the opening degree of the variable nozzle vane 16 and the drive torque required of the actuator to rotate the drive ring 20 in the case where the lifting pins 25 are not provided in the variable nozzle device 8. Hereinafter, the opening degree of the variable nozzle vane 16 will be simply referred to as the nozzle opening degree.

[0047] As shown in FIG. 11, the driving torque of the actuator in the process of changing the nozzle opening from fully open (maximum) to fully closed (minimum) tends to be greater than the driving torque of the actuator in the process of changing the nozzle opening from fully closed to fully open.

[0048] The reason why the above-mentioned relationship between the nozzle opening and the drive torque is obtained will be described below. In a typical variable nozzle device, a torque is applied to the variable nozzle vane in a direction to open the variable nozzle vane (the direction of the arrow d0 in FIG. 2) due to the fluid force of the exhaust gas flowing in from the scroll passage. Therefore, when the variable nozzle vane is rotated in a closing direction (when the drive ring 20 is rotated in the direction of the arrow d1 in FIG. 2), it is necessary to change the nozzle opening against the torque in the direction of the arrow d0 due to the fluid force of the exhaust gas. Therefore, it is considered that the drive torque required for the actuator is larger than that required for changing the nozzle opening in an opening direction. Therefore, it is desirable to reduce the drive torque required for the actuator when rotating the variable nozzle vane in a closing direction from the viewpoint of miniaturization of the actuator, etc.

[0049] Therefore, for example, as shown in FIG. 12, if the position where the drive ring 20 receives the force to rotate the drive ring 20 (the position of the pin 23) is defined as the 0 degree position in the circumferential direction of the drive ring 20, and the rotation direction d1 of the drive ring 20 for rotating the variable nozzle vane 16 in the closing direction is defined as the positive direction of the position in the circumferential direction of the drive ring 20, then it is desirable that the variable nozzle device 8 be provided with a lifting pin 25 of the pinned vane lever 18A within a range of 180 degrees to 360 degrees (more preferably within a range of 225 degrees to 315 degrees) in the circumferential direction of the drive ring 20.

[0050] This suppresses the increase in friction between the inner surface 20a of the drive ring 20 and the first annular member 12 that occurs when the variable nozzle vane 16 is rotated in the closing direction, and suppresses the increase in the driving torque required for the actuator.

[0051] 11, in the conventional variable nozzle device, it can be seen that the drive torque required of the actuator is particularly large at an opening degree near full open (for example, region S1 where the nozzle opening degree is 65% to 95%) and an opening degree near full closed (for example, region S2 where the nozzle opening degree is 0% to 30%) in the process of changing the nozzle opening degree from full open to full closed. For this reason, it is desirable to determine the arrangement of the pin-type vane lever 18A so as to reduce the drive torque required of the actuator for each of the opening degrees near full open (the above region S1) and the opening degrees near full closed (the above region S2) in the process of changing the nozzle opening degree from full open to full closed.

[0052] Also, as shown in FIG. 12, in the process of changing the nozzle opening of the variable nozzle device 8 from fully open (maximum) to fully closed (minimum), if the direction of the driving force that the pin 23 of the drive ring 20 receives from an actuator (not shown) at an opening close to fully open is F1, and the direction of the driving force that the pin 23 of the drive ring 20 receives from an actuator (not shown) at an opening close to fully closed is F2, then as the drive ring 20 rotates, the position of the pin 23 changes from the position of the pin 23 shown by the solid line to the position of the pin 23 shown by the dashed line, and therefore directions F1 and F2 are different directions.

[0053] 12, the multiple vane levers 18 of the variable nozzle device 8 are provided with lifting pins 25 of first pinned vane levers 18A1 (two first pinned vane levers 18A1 in the illustrated example) described below within a range of 180 degrees to 270 degrees in the circumferential direction of the drive ring 20 in order to reduce the drive torque of the actuator at an opening degree near full open in the process of changing the nozzle opening degree of the variable nozzle device 8 from full open to full closed. Also, the variable nozzle device 8 is provided with lifting pins 25 of second pinned vane levers 18A2 (two second pinned vane levers 18A2 in the illustrated example) described below within a range of 270 degrees to 360 degrees in the circumferential direction of the drive ring 20 in order to reduce the drive torque of the actuator at an opening degree near full closed in the process of changing the nozzle opening degree of the variable nozzle device 8 from full closed to full open.

[0054] Figure 13 is an axial view showing a schematic diagram of the positional relationship between each part of the first pin-type vane lever 18A1 and the inner surface 20a of the drive ring 20 (the surface of the drive ring 20 that abuts against the lifting pin 25) when the drive ring 20 is not lifted by the lifting pin 25.

[0055] In the configuration shown in Figure 13, if the position on the outer circumferential surface 25a of the lifting pin 25 that is farthest from the rotation axis C of the first pinned vane lever 18A1 is defined as P1, the distance between position P1 and the rotation axis C of the first pinned vane lever 18A1 is defined as r1, and the distance between the inner circumferential surface 20a of the drive ring 20 (the surface of the drive ring 20 that abuts against the lifting pin 25) when the drive ring 20 is not lifted by the lifting pin 25 is defined as r0, the lifting pin 25 is positioned so that r1>r0 is satisfied. In Figure 13, the trajectory of position P1 when the first pinned vane lever 18A1 is rotated around the rotation axis C of the first pinned vane lever 18A1 is shown by a dotted circle, and the drive ring 20 is lifted radially outward by the lifting pin 25 when the above-mentioned trajectory of the lifting pin 25 exceeds the position of the inner surface 20a of the drive ring 20 when the drive ring 20 is not lifted by the lifting pin 25.

[0056] 13 is disposed at a position shifted in the direction d1 from the center of the width direction of the first pinned vane lever 18A1 (the position of the dashed line in FIG. 13). As a result, when the nozzle opening degree is near full opening (for example, within the range of 65% to 95%), the difference (r1-r0) between the distance r1 and the distance r0 is maximized, and the lifting effect of the lifting pin 25 on the drive ring 20 is maximized. In other words, the distance r between the inner peripheral surface 20a of the drive ring 20 and the rotation axis C of the first pinned vane lever 18A1 is maximized when the nozzle opening degree is within the range of 65% to 95%. The width direction of the first pinned vane lever 18A1 is a direction perpendicular to each of the rotation axis C of the first pinned vane lever 18A1 and the longitudinal direction of the first pinned vane lever 18A1 (the direction along the dashed line in FIG. 13).

[0057] 13, in the process of changing the nozzle opening in the closing direction, it is possible to effectively reduce the frictional force between the inner circumferential surface 20a of the drive ring 20 and the first annular member 12 at a nozzle opening close to full open (65% to 95%) where the driving force for rotating the drive ring 20 tends to be large. This makes it possible to suppress an increase in the driving force for rotating the drive ring 20 and suppress an increase in the size of the actuator.

[0058] Figure 14 is an axial view showing a schematic diagram of the positional relationship between each part of the second pin-type vane lever 18A2 and the inner surface 20a of the drive ring 20 (the surface of the drive ring 20 that abuts against the lifting pin 25) when the drive ring 20 is not lifted by the lifting pin 25.

[0059] In the configuration shown in Figure 14, if the position on the outer circumferential surface 25a of the lifting pin 25 that is farthest from the rotation axis C of the second pinned vane lever 18A2 is P1, the distance between position P1 and the rotation axis C of the second pinned vane lever 18A2 is r1, and the distance between the inner circumferential surface 20a of the drive ring 20 (the surface of the drive ring 20 that abuts against the lifting pin 25) when the drive ring 20 is not lifted by the lifting pin 25 and the rotation axis C of the second pinned vane lever 18A2 is r0, the lifting pin 25 is positioned so that r1>r0 is satisfied. In Figure 14, the trajectory of position P1 when the second pinned vane lever 18A2 is rotated around the rotation axis C of the second pinned vane lever 18A2 is shown by a dotted circle, and the drive ring 20 is lifted by the lifting pin 25 when the above-mentioned trajectory of the lifting pin 25 exceeds the position of the inner surface 20a of the drive ring 20 radially outward when the drive ring 20 is not lifted by the lifting pin 25.

[0060] The lifting pin 25 shown in Fig. 14 is disposed at a position shifted from the center in the width direction of the second pin vane lever 18A2 (the position of the dashed line in Fig. 14) in the opposite direction to the first direction d1 in the circumferential direction of the drive ring 20. As a result, when the nozzle opening degree is close to the fully closed opening degree (for example, within the range of 0% to 30%), the difference (r1-r0) between the distance r1 and the distance r0 is maximized, and the lifting effect of the drive ring 20 by the lifting pin 25 is maximized. In other words, the distance r between the inner peripheral surface 20a of the drive ring 20 and the rotation axis C of the second pin vane lever 18A2 is maximized when the nozzle opening degree is within the range of 0% to 30%. The width direction of the second pinned vane lever 18A2 is a direction perpendicular to both the rotation axis C of the second pinned vane lever 18A2 and the longitudinal direction of the second pinned vane lever 18A2 (the direction along the dashed line in FIG. 14).

[0061] 14, in the process of changing the nozzle opening in the closing direction, it is possible to effectively reduce the frictional force between the drive ring 20 and the first annular member 12 at a nozzle opening close to the fully closed state (0% to 30%) where the torque for rotating the drive ring 20 tends to become large. This makes it possible to suppress an increase in the drive torque required of the actuator for driving the drive ring 20, and to suppress an increase in the size of the actuator.

[0062] In some embodiments, the arrangement of the pin-equipped vane lever 18A may be determined so as to reduce the drive torque required of the actuator for an intermediate opening degree close to fully closed in the process of changing the nozzle opening degree of the variable nozzle device 8 from fully closed to fully open (for example, region S3 in FIG. 11 where the nozzle opening degree is 10% to 70%). At an intermediate opening degree close to fully closed in the process of changing the nozzle opening degree from fully closed to fully open, a drive force for rotating the drive ring 20 acts from the actuator to the pin 23 in the direction of arrow F3 shown in FIG.

[0063] In this case, as shown in Fig. 15, the multiple vane levers 18 of the variable nozzle device 8 may be provided with a lifting pin 25 of a third pinned vane lever 18A3 described below within a range of 90 degrees to 180 degrees in the circumferential direction of the drive ring 20. In the example shown in Fig. 15, the multiple vane levers 18 of the variable nozzle device 8 are provided with two third pinned vane levers 18A3 within a range of 90 degrees to 180 degrees in the circumferential direction of the drive ring 20.

[0064] Figure 16 is an axial view showing the positional relationship between each part of the third pin-type vane lever 18A3 and the inner surface 20a of the drive ring 20 (the surface of the drive ring 20 that abuts against the lifting pin 25) when the drive ring 20 is not lifted by the lifting pin 25.

[0065] As shown in Figure 16, if the position on the outer circumferential surface 25a of the lifting pin 25 that is farthest from the rotation axis C of the third pinned vane lever 18A3 is defined as P1, the distance between position P1 and the rotation axis C of the third pinned vane lever 18A3 is defined as r1, and the distance between the inner circumferential surface 20a of the drive ring 20 (the surface of the drive ring 20 that abuts against the lifting pin 25) when the drive ring 20 is not lifted by the lifting pin 25 is defined as r0, the lifting pin 25 is positioned so that r1>r0 is satisfied. In Figure 16, the trajectory of position P1 when the third pinned vane lever 18A3 is rotated around the rotation axis C of the third pinned vane lever 18A3 is shown by a dotted circle, and the drive ring 20 is lifted by the lifting pin 25 when the above-mentioned trajectory of the lifting pin 25 exceeds the position of the inner surface 20a of the drive ring 20 radially outward when the drive ring 20 is not lifted by the lifting pin 25.

[0066] The lifting pin 25 shown in Fig. 16 is disposed at a position shifted in the circumferential direction of the drive ring 20 from the center in the width direction of the third pin vane lever 18A3 (the position of the dashed line in Fig. 16) in the opposite direction to the direction d1. In the third pin vane lever 18A3, when the nozzle opening is an intermediate opening degree close to fully closed (for example, a nozzle opening degree within a range of 20% to 50%), the difference (r1-r0) between the distance r1 and the distance r0 is maximized, and the lifting effect of the drive ring 20 by the lifting pin 25 is maximized. In other words, the distance r between the inner peripheral surface 20a of the drive ring 20 and the rotation axis C of the third pin vane lever 18A3 is maximized when the nozzle opening degree is within a range of 20% to 50%. The width direction of the third pin vane lever 18A3 is a direction perpendicular to both the rotation axis C of the third pin vane lever 18A3 and the longitudinal direction of the third pin vane lever 18A3 (the direction along the dashed line in FIG. 16).

[0067] 15 and 16, in the process of changing the nozzle opening in the opening direction, it is possible to effectively reduce the frictional force between the drive ring 20 and the first annular member 12 at an intermediate nozzle opening (20% to 50%) close to the fully closed position, where the torque required to rotate the drive ring 20 may become large. This makes it possible to suppress an increase in the drive torque required of the actuator for driving the drive ring 20, and to suppress an increase in the size of the actuator.

[0068] FIG. 17 is a view of a variable nozzle device 8D according to another embodiment, viewed from the bearing casing 6 side (compressor side) along the axial direction of the turbine wheel 2. In some embodiments, as shown in FIG. 17, for example, the variable nozzle device 8D includes a connecting member 40 (drive ring pressing portion) that connects a pair of adjacent vane levers 18B, 18C among the vane levers 18. In the illustrated example, a pin 42 protruding in the axial direction of the drive ring 20 is provided on the surface 18d of each of the vane levers 18B and 18C opposite to the exhaust gas flow path 24, and one end of the connecting member 40 is rotatably connected to the pin 42 provided on the vane lever 18B, and the other end of the connecting member 40 is rotatably connected to the pin 42 provided on the vane lever 18C. A pin 44 protruding in the axial direction of the drive ring 20 is provided on the surface 20b of the drive ring 20 opposite to the exhaust gas flow path 24. The connecting member 40 is located inside the pin 44 in the radial direction of the drive ring 20 and is provided so as to abut against the pin 44 in the radial direction of the drive ring 20.

[0069] In this configuration, the connecting member 40 swings along a circular arc as indicated by an arrow d3 in conjunction with the rotation of the pair of vane levers 18B, 18C, and can lift the drive ring 20.

[0070] Therefore, as shown in FIG. 17, the variable nozzle device 8D is provided with the connecting member 40 (and the pins 42 and 44 of the pair of vane levers 18B, 18C) within a range of 180 degrees to 360 degrees (more preferably within a range of 225 degrees to 315 degrees) in the circumferential direction of the drive ring 20, thereby making it possible to reduce the driving torque of the drive ring 20 when the nozzle opening of the variable nozzle device 8D is changed in the closing direction.

[0071] In the configuration shown in Fig. 17, the pin 42 provided on the vane lever 18B is disposed at a position shifted in the above-mentioned direction d1 in the circumferential direction from the center in the width direction of the vane lever 18B, and the pin 42 provided on the vane lever 18C is disposed at a position shifted in the above-mentioned direction d1 in the circumferential direction of the drive ring 20 from the center in the width direction of the vane lever 18C. In addition, when the nozzle opening degree is an opening degree close to full opening (for example, an opening degree within a range of 65% to 95% corresponding to the region S2 in Fig. 11), the lifting effect of the drive ring 20 by the connecting member 40 is maximized. In other words, the distance between the inner circumferential surface 20a of the drive ring 20 and the rotation axis C of the vane lever 18B is maximized when the nozzle opening degree is within a range of 65% to 95%, and the distance between the inner circumferential surface 20a of the drive ring 20 and the rotation axis C of the vane lever 18C is maximized when the nozzle opening degree is within a range of 65% to 95%. The width direction of vane lever 18B is a direction perpendicular to both the rotation axis of vane lever 18B and the longitudinal direction of vane lever 18B, and the width direction of vane lever 18C is a direction perpendicular to both the rotation axis of vane lever 18C and the longitudinal direction of vane lever 18C.

[0072] 17, by providing the connecting member 40, the position at which the drive ring 20 is pressed in the radial direction of the drive ring 20 can be set to any position in the circumferential direction of the drive ring 20, and the drive ring 20 can be displaced by being pressed in the radial direction of the drive ring 20 at positions away from each of the vane levers 18B, 18C in the circumferential direction of the drive ring 20. Furthermore, by adjusting the position at which the connecting member 40 is provided, the frictional force between the inner circumferential surface 20a of the drive ring 20 and the first annular member 12 at any nozzle opening degree can be reduced.

[0073] FIG. 18 is a view of a variable nozzle device 8E according to another embodiment, viewed from the bearing casing 6 side (compressor side) along the axial direction of the turbine wheel 2.

[0074] In some embodiments, as shown in FIG. 18, for example, the variable nozzle device 8E includes a connecting member 40 (drive ring pressing portion) that connects a pair of adjacent vane levers 18D, 18E among the multiple vane levers 18. In the illustrated example, a pin 42 protruding in the axial direction of the drive ring 20 is provided on the surface 18d of each of the vane levers 18D and 18E opposite to the exhaust gas flow path 24, and one end of the connecting member 40 is rotatably connected to the pin 42 provided on the vane lever 18D, and the other end of the connecting member 40 is rotatably connected to the pin 42 provided on the vane lever 18E. A pin 44 protruding in the axial direction of the drive ring 20 is provided on the surface 20b of the drive ring 20 opposite to the exhaust gas flow path 24. The connecting member 40 is located inside the pin 44 in the radial direction of the drive ring 20 and is provided so as to abut against the pin 44 in the radial direction of the drive ring 20.

[0075] In this configuration, the connecting member 40 swings along a circular arc as indicated by an arrow d4 in conjunction with the rotation of the pair of vane levers 18D, 18E, and can lift the drive ring 20.

[0076] Therefore, as shown in FIG. 18, the variable nozzle device 8E is provided with the connecting member 40 (and the pins 42 and 44 of the pair of vane levers 18D, 18E) within a range of 0 degrees to 180 degrees (more preferably within a range of 45 degrees to 135 degrees) in the circumferential direction of the drive ring 20, thereby making it possible to reduce the driving torque of the drive ring 20 when the nozzle opening of the variable nozzle device is changed in the opening direction (when the drive ring is rotated in direction d2).

[0077] 18, the pin 42 provided on the vane lever 18D is disposed at a position shifted from the center in the width direction of the vane lever 18D in a direction d2 (the rotation direction of the drive ring 20 when the nozzle opening is changed to the open direction) which is a direction opposite to the above-mentioned direction d1 in the circumferential direction of the drive ring 20, and the pin 42 provided on the vane lever 18E is disposed at a position shifted in the above-mentioned direction d2 in the circumferential direction of the drive ring 20 from the center in the width direction of the vane lever 18E. Also, when the nozzle opening is close to the fully closed opening (for example, an opening within a range of 0% to 30% corresponding to the region S1 in FIG. 11), the lifting effect of the drive ring 20 by the connecting member 40 is maximized. In other words, the distance r between the inner peripheral surface 20a of the drive ring 20 and the rotation axis C of the vane lever 18D is maximum when the nozzle opening degree is within a range of 0% to 30%, and the distance r between the inner peripheral surface 20a of the drive ring 20 and the rotation axis C of the vane lever 18E is maximum when the nozzle opening degree is within a range of 0% to 30%. Note that the width direction of the vane lever 18D is a direction perpendicular to both the rotation axis of the vane lever 18D and the longitudinal direction of the vane lever 18D, and the width direction of the vane lever 18E is a direction perpendicular to both the rotation axis of the vane lever 18E and the longitudinal direction of the vane lever 18E.

[0078] 18, by providing the connecting member 40, the position at which the drive ring 20 is pressed in the radial direction of the drive ring 20 can be set to any position in the circumferential direction of the drive ring 20, and the drive ring 20 can be displaced by being pressed in the radial direction of the drive ring 20 at positions away from each of the vane levers 18B, 18C in the circumferential direction of the drive ring 20. Furthermore, by adjusting the position at which the connecting member 40 is provided, the frictional force between the inner circumferential surface 20a of the drive ring 20 and the first annular member 12 at any nozzle opening degree can be reduced.

[0079] The present disclosure is not limited to the above-described embodiments, and includes modifications to the above-described embodiments and appropriate combinations of these modifications.

[0080] In some embodiments, as shown in FIG. 19, for example, in the variable nozzle device 8 (8A to 8C) described above, the lifting pin 25 may be configured as a separate part from the vane lever 18. This is advantageous in terms of workability of the vane lever 8 compared to a case where the lifting pin 25 is formed as a single part together with the vane lever 8. It is also advantageous in that any shape, such as a polygon, can be easily adopted as the cross-sectional shape of the lifting pin 25. The lifting pin 25 may be fixed, for example, by press-fitting into a through hole that passes through the main body 18a of the vane lever 18 in the axial direction of the drive ring 20, or may be fixed to the main body 18a of the vane lever 18 by welding or the like.

[0081] In some embodiments, as shown in Fig. 20, the pinned vane lever 18A may be provided with two lifting pins 25. In the example shown in Fig. 20, the two lifting pins 25 provided on the pinned vane lever 18A are arranged on one side and the other side of the center in the width direction of the pinned vane lever 18A. In this case, for example, the drive ring 20 can be lifted both when the nozzle opening degree is close to full open (for example, within a range of 65% to 95% corresponding to the region S2 in Fig. 11) and when the nozzle opening degree is close to full closed (for example, within a range of 0% to 30% corresponding to the region S1 in Fig. 11).

[0082] The contents described in each of the above embodiments can be understood, for example, as follows.

[0083] (1) A variable nozzle device according to at least one embodiment of the present disclosure, A variable nozzle device (for example, the variable nozzle device 8 (8A to 8E) described above) of a variable geometry turbocharger (for example, the variable geometry turbocharger 100 described above), A first annular member (e.g., the first annular member 12 described above); a second annular member (e.g., the above-mentioned second annular member 14) that is provided opposite to the first annular member and forms, between the first annular member and the second annular member, an exhaust gas passage (e.g., the above-mentioned exhaust gas passage 24) for guiding exhaust gas from a scroll passage (e.g., the above-mentioned scroll passage 10) that is formed on the outer periphery side of a turbine wheel (e.g., the above-mentioned turbine wheel 2) of the turbocharger to the turbine wheel; A rotatable variable nozzle vane (for example, the above-mentioned variable nozzle vane 16) provided in the exhaust gas flow passage; a first vane lever (for example, the above-mentioned pinned vane lever 18A, the first pinned vane lever 18A1, the second pinned vane lever 18A2, the third pinned vane lever 18A3, the vane lever 18B, the vane lever 18C, the vane lever 18D, or the vane lever 18E) connected to a shaft portion of the variable nozzle vane; A drive ring (e.g., the drive ring 20 described above) configured to engage with the first vane lever and rotate the first vane lever around the rotation axis of the shaft portion; a drive ring pressing portion (e.g., the lifting pin 25 or the connecting member 40) provided on the first vane lever and configured to change the distance between the inner peripheral surface of the drive ring and the rotation axis of the first vane lever by pressing and displacing the drive ring in the radial direction of the drive ring when the first vane lever rotates; Equipped with.

[0084] According to the variable nozzle device described in (1) above, when the first vane lever rotates, the drive ring pressing portion presses and displaces the drive ring in the radial direction of the drive ring, thereby changing the distance between the inner circumferential surface of the drive ring and the rotation axis of the first vane lever. Therefore, by arranging the drive ring pressing portion so that the distance between the inner circumferential surface of the drive ring and the rotation axis of the pin-equipped vane lever becomes large at the nozzle opening degree at which the driving force for rotating the drive ring is likely to be large, the frictional force between the inner circumferential surface of the drive ring and the first annular member at the nozzle opening degree can be reduced. This makes it possible to suppress an increase in the driving force for rotating the drive ring and to suppress an increase in the size of the actuator for rotating the drive ring.

[0085] (2) In some embodiments, in the variable nozzle device described in (1) above, The drive ring pressing portion is a pin (for example, the above-mentioned lifting pin 25) that protrudes in the axial direction of the drive ring from a surface of the first vane lever on the drive ring side (for example, the above-mentioned surface 18c).

[0086] According to the variable nozzle device described in (2) above, the effect of (1) above can be obtained with a simple configuration.

[0087] (3) In some embodiments, in the variable nozzle device described in (2) above, the drive ring includes a protrusion (e.g., the protrusion 26 described above) protruding in the axial direction of the drive ring from a surface of the drive ring on the first vane lever side (e.g., the surface 20c described above), the protrusion is located on an outer side of the pin in a radial direction of the drive ring, The pin is configured to press the protrusion in a radial direction of the drive ring when the first vane lever rotates, thereby displacing the drive ring.

[0088] According to the variable nozzle device described in (3) above, the convex portion can be formed radially outward of the drive ring rather than on the inner surface of the drive ring. This allows the rotation radius of the pin to be larger than that of the configuration described in (6) below, and the frictional force between the drive ring and the first annular member can be reduced over a wide range in the circumferential direction of the drive ring.

[0089] (4) In some embodiments, in the variable nozzle device described in (3) above, In a cross section perpendicular to the axial direction of the drive ring, the radially inner surface of the convex portion of the drive ring (eg, the above-mentioned surface 26a) is formed by a concave curve (eg, the above-mentioned concave curve 28).

[0090] According to the variable nozzle device described in (4) above, the frictional force between the drive ring and the first annular member can be reduced over a wide range in the circumferential direction of the drive ring, compared to when the radially inner surface of the drive ring at the convex portion is configured by a flat surface.

[0091] (5) In some embodiments, in the variable nozzle device described in (2) above, The surface of the drive ring facing the first vane lever (e.g., the surface 20c described above) includes a recess (e.g., the recess 32 described above), The tip of the pin is located inside the recess, The pin is configured to displace the drive ring by pressing a surface of the inner surface of the recess that faces radially inward of the drive ring (e.g., the above-mentioned surface 32a1) in the radial direction of the drive ring when the first vane lever rotates.

[0092] According to the variable nozzle device described in (5) above, the recesses can be formed radially outward of the inner peripheral surface of the drive ring, so that the rotation radius of the pin can be made larger than in the configuration described in (6) below, and the frictional force between the drive ring and the first annular member can be reduced over a wide range in the circumferential direction of the drive ring. Also, compared to the configuration described in (3) above, the contact area between the pin and the drive ring can be made wider, which is advantageous in terms of wear resistance.

[0093] (6) In some embodiments, in the variable nozzle device described in (2) above, The pin is configured to displace the drive ring by pressing an inner circumferential surface of the drive ring (for example, the above-mentioned inner circumferential surface 20a) in the radial direction of the drive ring when the first vane lever rotates.

[0094] The variable nozzle device described in (6) above is advantageous in terms of strength since it is not necessary to provide a special structure such as the convex portion of (3) or the concave portion of (5) above at the portion of the drive ring that comes into contact with the pin. Also, it is advantageous in terms of wear resistance since the contact area between the drive ring and the pin can be made wider.

[0095] (7) In some embodiments, in the variable nozzle device according to any one of (2) to (6) above, The pin is a separate part from the first vane lever.

[0096] The variable nozzle device described in (7) above is advantageous in terms of workability of the first vane lever compared to a case where the first vane lever is formed as a single part, and is also advantageous in that it makes it easier to adopt any shape, such as a polygon, for the pin.

[0097] (8) In some embodiments, in the variable nozzle device according to any one of (2) to (7) above, When viewed in the axial direction of the drive ring, the pin is disposed at a position shifted in the circumferential direction of the drive ring from the center in the width direction of the first vane lever.

[0098] According to the variable nozzle device described in (8) above, it is possible to reduce the frictional force between the drive ring and the first annular member when the nozzle opening degree is close to the fully open or fully closed position.

[0099] (9) In some embodiments, in the variable nozzle device described in (1) above, Further provided with a second vane lever (for example, the above-mentioned vane lever 18C) adjacent to the first vane lever (for example, the above-mentioned vane lever 18B), The drive ring pressing portion is a connecting member (for example, the above-mentioned connecting member 40) that connects the first vane lever and the second vane lever, The connecting member is configured to press and displace the drive ring in a radial direction of the drive ring when the first vane lever rotates.

[0100] According to the variable nozzle device described in (9) above, by providing a connecting member, the position where the drive ring is pressed in the radial direction of the drive ring can be set to any position in the circumferential direction of the drive ring, and the drive ring can be displaced by being pressed in the radial direction of the drive ring at a position away from the vane lever in the circumferential direction of the drive ring. Furthermore, by adjusting the position where the connecting member is provided, the frictional force between the inner circumferential surface of the drive ring and the first annular member at any nozzle opening degree can be reduced.

[0101] (10) In some embodiments, in the variable nozzle device according to any one of (1) to (9) above, The distance between the inner circumferential surface of the drive ring and the rotation axis of the first vane lever is maximum when the opening degree of the variable nozzle vane is within a range of 65% to 95%.

[0102] According to the variable nozzle device described in (10) above, in the process of changing the nozzle opening in the closing direction, it is possible to effectively reduce the frictional force between the drive ring and the first annular member at the nozzle opening near full open (65% to 95%) where the frictional force between the drive ring and the first annular member tends to be large, thereby suppressing an increase in the driving force for rotating the drive ring and an increase in the size of the actuator for rotating the drive ring.

[0103] (11) In some embodiments, in the variable nozzle device according to any one of (1) to (9) above, The distance between the inner circumferential surface of the drive ring and the rotation axis of the first vane lever is maximum when the opening degree of the variable nozzle vane is within a range of 0% to 30%.

[0104] According to the variable nozzle device described in (11) above, in the process of changing the nozzle opening in the closing direction, the frictional force between the drive ring and the first annular member can be effectively reduced at the nozzle opening near the fully closed position (0% to 30%) where the frictional force between the drive ring and the first annular member tends to be large. This makes it possible to suppress an increase in the driving force for rotating the drive ring and to suppress an increase in the size of the actuator for rotating the drive ring.

[0105] (12) In some embodiments, in the variable nozzle device according to any one of (1) to (11) above, The drive ring includes a force receiving portion (e.g., the above-mentioned pin 23) that receives a force that rotates the drive ring, With respect to the circumferential direction of the drive ring, if the position of the force receiving portion is defined as the 0 degree position in the circumferential direction of the drive ring, and the rotation direction of the drive ring for rotating the variable nozzle vanes in the closing direction is defined as the positive direction of the circumferential position of the drive ring, then the drive ring pressing portion is located within a range of 180 degrees to 360 degrees in the circumferential direction of the drive ring.

[0106] In a typical variable nozzle device, a torque is applied to the variable nozzle vane in a direction to open the variable nozzle vane due to the fluid force of the exhaust gas flowing in from the scroll passage. Therefore, when rotating the variable nozzle vane in a closing direction, it is necessary to change the nozzle opening against the torque due to the fluid force of the exhaust gas, so the torque required to rotate the drive ring is larger than when changing the nozzle opening in an opening direction. Therefore, from the viewpoint of miniaturizing the actuator, it is desirable to reduce the driving force for rotating the drive ring when rotating the variable nozzle vane in a closing direction.

[0107] Therefore, by providing a drive ring pressing portion within a range of 180 degrees to 360 degrees in the circumferential direction of the drive ring as described in (12) above, it is possible to suppress an increase in friction between the inner surface of the drive ring and the first annular member that occurs when the variable nozzle vane is rotated in the closing direction, and to suppress an increase in the driving force for rotating the drive ring.

[0108] (13) A variable geometry turbocharger according to at least one embodiment of the present disclosure (for example, the variable geometry turbocharger 100 described above) A variable nozzle device according to any one of (1) to (12) above (for example, the variable nozzle device 8 (8A to 8E) described above), The turbine wheel; a casing that houses the turbine wheel; Equipped with.

[0109] According to the variable geometry turbocharger described in (13) above, since it is equipped with the variable nozzle device described in any one of (1) to (12) above, it is possible to suppress an increase in the driving force for rotating the drive ring and to suppress an increase in the size of the actuator for rotating the drive ring. [Explanation of symbols]

[0110] 2. Turbine wheel 4. Turbine casing 6 Bearing casing 8(8A~8E) Variable nozzle device 10 Scroll passage 12 First annular member 13 Protrusion 13a Outer surface 14 Second annular member 16 Variable Nozzle Vane 16a Shaft 18 Vane Lever 18 Vane Lever 18A Vane lever with pin 18A1 First pinned vane lever 18A2 Second pinned vane lever 18A3 3rd pinned vane lever 18a Lever body 18b Engagement protrusion 18c Drive ring side 20 Drive Ring 20a Inner surface 20b Opposite side 20c Pinned vane lever side 22 Outer periphery 22a Notch 23 pin 24 Exhaust gas flow path 25 Lifting pin 25a Outer surface 25b Tip 26 Convex 26a Radial inner surface of drive ring 28 concave curve 30 support holes 32 Recess 32a Inside 32a1 Radial inward surface of drive ring 100 Variable Geometry Turbocharger

Claims

1. A variable nozzle device for a variable geometry turbocharger, comprising: A first annular member; a second annular member provided opposite to the first annular member and defining, between the first annular member and the second annular member, an exhaust gas passage for guiding exhaust gas from a scroll passage formed on an outer circumferential side of a turbine wheel of the turbocharger to the turbine wheel; A rotatable variable nozzle vane provided in the exhaust gas flow passage; A first vane lever connected to a shaft portion of the variable nozzle vane; a drive ring configured to engage with the first vane lever and rotate the first vane lever about a rotation axis of the shaft portion; a drive ring pressing portion provided on the first vane lever and configured to change a distance between an inner peripheral surface of the drive ring and a rotation axis of the first vane lever by pressing and displacing the drive ring in a radial direction of the drive ring when the first vane lever rotates; A variable nozzle device comprising:

2. The variable nozzle device according to claim 1 , wherein the drive ring pressing portion is a pin that protrudes in an axial direction of the drive ring from a surface of the first vane lever facing the drive ring.

3. the drive ring includes a protrusion protruding in an axial direction of the drive ring from a surface of the drive ring on a side of the first vane lever, the protrusion is located on an outer side of the pin in a radial direction of the drive ring, The variable nozzle device according to claim 2 , wherein the pin is configured to displace the drive ring by pressing the protrusion in a radial direction of the drive ring when the first vane lever rotates.

4. 4. The variable nozzle device according to claim 3, wherein in a cross section perpendicular to an axial direction of the drive ring, a radially inner surface of the convex portion of the drive ring is defined by a concave curve.

5. The drive ring has a surface on the first vane lever side that includes a recess. The tip of the pin is located inside the recess, 3. The variable nozzle device according to claim 2, wherein the pin is configured to displace the drive ring by pressing an inner surface of the recess that faces radially inward of the drive ring in a radial direction of the drive ring when the first vane lever rotates.

6. 3. The variable nozzle device according to claim 2, wherein the pin is configured to displace the drive ring by pressing an inner circumferential surface of the drive ring in a radial direction of the drive ring when the first vane lever rotates.

7. The variable nozzle device according to claim 2 , wherein the pin is configured as a separate part from the first vane lever.

8. 8. The variable nozzle device according to claim 2, wherein when viewed from the axial direction of the drive ring, the pin is positioned at a position shifted circumferentially of the drive ring from the center of the width of the first vane lever.

9. Further comprising a second vane lever adjacent to the first vane lever, the drive ring pressing portion is a connecting member that connects the first vane lever and the second vane lever, The variable nozzle device according to claim 1 , wherein the connecting member is configured to press and displace the drive ring in a radial direction of the drive ring when the first vane lever rotates.

10. The variable nozzle device according to any one of claims 1 to 9, wherein the distance between the inner surface of the drive ring and the rotation axis of the first vane lever is maximum when the opening degree of the variable nozzle vane is within a range of 65% to 95%.

11. The variable nozzle device according to any one of claims 1 to 9, wherein the distance between the inner surface of the drive ring and the rotation axis of the first vane lever is maximum when the opening degree of the variable nozzle vane is within a range of 0% to 30%.

12. the drive ring includes a force receiving portion that receives a force that rotates the drive ring, The variable nozzle device according to any one of claims 1 to 11, wherein when the position of the force receiving portion is defined as a position of 0 degrees in the circumferential direction of the drive ring, and the rotation direction of the drive ring for rotating the variable nozzle vane in the closing direction is defined as a positive direction of the circumferential position of the drive ring, the drive ring pressing portion is located within a range of 180 degrees to 360 degrees in the circumferential direction of the drive ring.

13. A variable nozzle device according to any one of claims 1 to 12, The turbine wheel; a casing that houses the turbine wheel; A variable geometry turbocharger.

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