Variable nozzle device and variable geometry turbocharger

Abstract

This variable nozzle device for a variable-capacity-type turbocharger comprises: a first annular member; a second annular member which forms an exhaust gas flow channel between the first annular member and the second annular member; a plurality of variable nozzle vanes which are turnable; a spacer member disposed in the exhaust gas flow channel such that spacing between the first annular member and the second annular member is maintained; and a fixed vane which is fixed at a position between the spacer member and a downstream-side variable nozzle vane in the exhaust gas flow channel.

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. This variable nozzle device includes a pair of annular members that form an exhaust gas passage for guiding exhaust gas from a scroll passage of a turbine to a turbine wheel, a plurality of variable nozzle vanes provided in the exhaust gas passage, and a spacer member for maintaining the gap between the pair of annular members. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] U.S. Pat. No. 1,035,8935 Summary of the Invention [Problem to be solved by the invention]

[0004] As a result of careful investigation by the inventors of the present application, it was found that when a spacer member is placed between multiple variable nozzle vanes in a variable nozzle device of a variable geometry turbocharger, negative vane torque, i.e., aerodynamic torque in the direction of closing the variable nozzle vane, is generated in the variable nozzle vane downstream of the spacer member at a certain nozzle opening.

[0005] Fig. 9 shows a wake W generated from a support pin 015 serving as a spacer member, and this wake W reduces the static pressure on the pressure surface of the adjacent variable nozzle vane 016D downstream of the support pin 015 in the circumferential direction among the multiple variable nozzle vanes 016 (see the upper side of Fig. 10). As a result, in the variable nozzle vane 016D downstream of the support pin 015, the torque in the direction of opening the variable nozzle vane 016D is reduced, and the overall aerodynamic torque based on the static pressure on the pressure surface (see the upper side of Fig. 10) and the static pressure on the suction pressure surface (see the lower side of Fig. 10) becomes negative. Fig. 11 shows that the aerodynamic torque of the variable nozzle vane 016D downstream of the support pin becomes 0 or less within a certain blade angle range.

[0006] If these variable nozzle vanes 016D are closed due to negative aerodynamic torque in the event of actuator failure, this is undesirable for the engine as it can accelerate the flow and cause an increase in turbine speed and engine overboost.

[0007] In view of the above circumstances, an object of at least one embodiment of the present disclosure is to provide a variable nozzle device capable of reducing the effect of wake generated from a spacer member, 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 plurality of rotatable variable nozzle vanes provided in the exhaust gas flow passage at intervals in a circumferential direction of the first annular member; a spacer member provided in the exhaust gas flow passage so as to maintain a gap between the first annular member and the second annular member; A downstream side of the flow of the exhaust gas along the circumferential direction in the exhaust gas flow passage is defined as a downstream side in the circumferential direction, and the variable nozzle vane adjacent to the downstream side of the spacer member in the circumferential direction among the plurality of variable nozzle vanes is defined as a downstream variable nozzle vane. A fixed vane is fixed to a position between the spacer member and the downstream variable nozzle vane in the exhaust gas flow passage, 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 reducing the effect of wake caused by a spacer member, 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] 2 is a schematic cross-sectional view showing an example of an AA cross section (cross section perpendicular to the axial direction) in the variable nozzle device shown in FIG. [Diagram 3] 3 is a schematic cross-sectional view showing an example of a cross section BB of the variable nozzle device shown in FIG. 2. [Figure 4] 3 is a schematic cross-sectional view showing another example of the cross section BB of the variable nozzle device shown in FIG. 2. [Diagram 5] 3 is a schematic cross-sectional view showing still another example of the cross section BB of the variable nozzle device shown in FIG. 2. [Figure 6] 3 is a schematic cross-sectional view showing still another example of the cross section BB of the variable nozzle device shown in FIG. 2. [Figure 7] FIG. 11 is a schematic cross-sectional view for explaining a modified example of the variable nozzle device. [Figure 8A] 13A and 13B are diagrams illustrating another example of a cross-sectional shape of a spacer member. [Figure 8B] 13 is a diagram showing yet another example of a cross-sectional shape of a spacer member. FIG. [Figure 9] FIG. 2 is a diagram showing the Mach number inside the turbine of a turbocharger, illustrating wake generation from a support pin, which is a cylindrical spacer member. [Figure 10] FIG. 11 is a diagram showing static pressure distribution on the pressure surface and the suction surface of the variable nozzle vane adjacent to the downstream side of the support pin. [Figure 11] 13 is a diagram showing the relationship between the torque around the rotation axis of each variable nozzle vane and the blade angle for the variable nozzle vane adjacent to the downstream side of the support pin and the other variable nozzle vanes among a plurality of variable nozzle vanes. FIG. 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) 1 is a schematic cross-sectional view showing a part of a cross section of a variable geometry turbocharger 100 according to one embodiment, taken along a rotation axis O. 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 arranged 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) The variable nozzle device 8 comprises a first annular member 12 (nozzle mount), a second annular member 14 (nozzle plate), a plurality of support pins 15, a plurality of variable nozzle vanes 16, a plurality of lever plates 18, a drive ring 20 and a plurality of fixed vanes 22.

[0017] 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. A plurality of support holes 30 (through holes) penetrating the first annular member 12 in the axial direction are formed in the first annular member 12 at intervals in the circumferential direction, and each of the support holes 30 rotatably supports a shaft portion 16a of the variable nozzle vane 16.

[0018] Hereinafter, unless otherwise specified, "axial direction" means the axial direction of the first annular member 12, "radial direction" means the radial direction of the first annular member 12, and "circumferential direction" means the circumferential direction of the first annular member 12, unless otherwise specified. The axial direction of the first annular member 12 coincides with the axial direction of the turbine wheel 2, the axial direction of the second annular member 14, and the axial direction of the drive ring 20. The radial direction of the first annular member 12 coincides with the radial direction of the turbine wheel 2, the radial direction of the second annular member 14, and the radial direction of the drive ring 20. The circumferential direction of the first annular member 12 coincides with the circumferential direction of the turbine wheel 2, the circumferential direction of the second annular member 14, and the circumferential direction of the drive ring 20.

[0019] 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.

[0020] The multiple support pins 15 are provided at intervals in the circumferential direction in the exhaust gas flow passage 24 between the first annular member 12 and the second annular member 14. Each of the multiple support pins 15 is fixed to at least one of the first annular member 12 and the second annular member 14. Each of the multiple support pins 15 functions as a spacer member for maintaining the distance between the first annular member 12 and the second annular member 14. The multiple support pins 15 may have the same shape and the same dimensions, and hereinafter, the description of the support pins 15 refers to each of the support pins 15 unless otherwise specified.

[0021] The multiple variable nozzle vanes 16 are arranged at intervals in the circumferential direction in the exhaust gas passage 24 between the first annular member 12 and the second annular member 14. Each of the variable nozzle vanes 16 is rotatably supported in a support hole 30 in the first annular member 12. The variable nozzle device 8 is configured to adjust the flow area of ​​the exhaust gas passage 24 by changing the blade angle of the multiple variable nozzle vanes 16. The multiple variable nozzle vanes 16 may have the same shape and the same dimensions, and hereinafter, the description of the variable nozzle vanes 16 will be a description of each of the variable nozzle vanes 16 unless otherwise specified.

[0022] In the variable nozzle device 8, the drive ring 20 is rotationally driven by a driving force transmitted from an actuator (not shown). When the drive ring 20 rotates, the lever plate 18 engaged with the drive ring 20 rotates the shaft portion 16a of the variable nozzle vane 16, and as a result, the variable nozzle vane 16 rotates and the blade angle of the variable nozzle vane 16 changes.

[0023] FIG. 2 is a schematic cross-sectional view showing an example of an AA cross section (cross section perpendicular to the axial direction) of the variable nozzle device 8 shown in FIG.

[0024] 2, the multiple support pins 15 are made up of three support pins 15, which are arranged at 120 degree intervals in the circumferential direction. Each of the support pins 15 is located outside the rotation center C of each of the variable nozzle vanes 16 in the radial direction.

[0025] Here, as shown in Figure 2, if the downstream side of the exhaust gas flow along the circumferential direction in the exhaust gas passage 24 (the downstream side in the rotational direction r of the turbine wheel 2) is defined as the downstream side in the circumferential direction, and the variable nozzle vane 16 among the multiple variable nozzle vanes 16 adjacent to the downstream side of the support pin 15 in the circumferential direction is defined as the downstream variable nozzle vane 16D, the fixed vane 22 is fixed at a position between the support pin 15 and the downstream variable nozzle vane 16D in the exhaust gas passage 24.

[0026] 2, the multiple fixed vanes 22 are composed of three fixed vanes 22 and are arranged at 120 degree intervals in the circumferential direction. The multiple fixed vanes 22 are fixed to positions between the support pins 15 and the downstream variable nozzle vane 16D in the exhaust gas passage 24 so as to correspond to the multiple support pins 15, respectively. The multiple fixed vanes 22 may have the same shape, the same dimensions, and the same blade angle, and hereinafter, the description of the fixed vanes 22 will be a description of each of the fixed vanes 22 unless otherwise specified.

[0027] In the example shown in Figure 2, the vane length L1 of the fixed vane 22 is larger than the diameter D of the support pin 15, the leading edge 22LE of the fixed vane 22 is located radially outward from the outer end 15e of the support pin 15 in the radial direction, and the trailing edge 22TE of the fixed vane 22 is located radially inward from the inner end 15i of the support pin 15 in the radial direction.

[0028] Moreover, the vane length L1 of the fixed vane 22 is smaller than the vane length L0 of the variable nozzle vane 16. The vane length L1 of the fixed vane 22 is the distance between the leading edge 22LE and the trailing edge 22TE of the fixed vane 22, and the vane length L0 of the variable nozzle vane 16 is the distance between the leading edge 16LE and the trailing edge 16TE of the variable nozzle vane 16.

[0029] 2, a midpoint M between the leading edge 22LE and the trailing edge 22TE of the fixed vane 22 is located radially outward of the rotation center C of the variable nozzle vane 16. Also, in the cross section shown in Fig. 2, the trailing edge 22TE of the fixed vane 22 is located radially outward of the rotation center C of the variable nozzle vane 16, or at the same position as the rotation center C of the variable nozzle vane in the radial direction.

[0030] If the blade angle of the fixed vane 22 is made too small, depending on the interval between the fixed vane 22 and the downstream variable nozzle vane 16D, the leading edge 16LE of the downstream variable nozzle vane 16D may interfere with the fixed vane 22 when the downstream variable nozzle vane 16D rotates, and if the blade angle of the fixed vane 22 is made too large, there is a risk of wake generation from the fixed vane 22 itself. For this reason, from the viewpoint of suppressing the generation of wake from the fixed vane 22 itself while avoiding interference between the leading edge 16LE of the downstream variable nozzle vane 16D and the fixed vane 22 when the downstream variable nozzle vane 16D rotates, when the blade angle of the downstream variable nozzle vane 16D at full opening (when the opening degree is maximum) is α and the blade angle of the fixed vane 22 is β, it is preferable to satisfy α-45°<β<α+45°, more preferably to satisfy α-30°<β<α+30°, and even more preferably to satisfy α-15°<β<α+15°. The blade angle is the angle that a straight line connecting the leading edge and trailing edge of the blade in question makes with a circumferential tangent at the position of the leading edge.

[0031] The effects achieved by the configuration shown in FIG. 2 will now be described. According to the variable nozzle device 8, by providing the fixed vane 22 at a position between the support pin 15 and the downstream variable nozzle vane 16D, the fixed vane 22 can prevent the wake generated from the support pin 15 from reaching the downstream variable nozzle vane 16D. This reduces the influence of the wake and prevents the direction of the torque acting on the downstream variable nozzle vane 16D from reversing from a direction that opens the downstream variable nozzle vane 16D to a direction that closes the downstream variable nozzle vane 16D. Therefore, in the event of a failure of an actuator (not shown) for rotating the multiple variable nozzle vanes 16, the downstream variable nozzle vane 16D is prevented from closing, and the risk of an excessive increase in the turbine rotation speed (the rotation speed of the turbine wheel 2) or an overboost of the engine (not shown) can be reduced.

[0032] In addition, since the leading edge 22LE of the fixed vane 22 is located radially outward of the outer end 15e of the support pin 15, and the trailing edge 22TE of the fixed vane 22 is located radially inward of the inner end 15i of the support pin 15, the wake generated from the support pin 15 can be effectively prevented from reaching the downstream variable nozzle vane 16D.

[0033] Furthermore, since the vane length L1 of the fixed vane 22 is greater than the diameter D of the support pin 15, the wake generated from the support pin 15 can be effectively prevented from reaching the downstream variable nozzle vane 16D.

[0034] Furthermore, since the vane length L1 of the fixed vane 22 is smaller than the vane length L0 of the variable nozzle vane 16, the fixed vane 22 can prevent the wake generated from the support pin 15 from reaching the downstream variable nozzle vane 16D downstream of the support pin 15, while suppressing an increase in flow resistance in the exhaust gas flow path 24 caused by the fixed vane 22.

[0035] In addition, since the support pin 15 is located radially outward of the rotation center C of the variable nozzle vane 16, the influence of the support pin 15 on the flow of the exhaust gas passage 24 on the turbine wheel 2 is suppressed, and a decrease in turbine efficiency is suppressed, compared to when the support pin 15 is located radially inward of the rotation center C of the variable nozzle vane 16.

[0036] Furthermore, in the above-mentioned AA cross section perpendicular to the axial direction, a midpoint M between the leading edge 22LE and the trailing edge 22TE of the fixed vane 22 is located radially outward of the rotation center C of the variable nozzle vane 16. Therefore, compared to a case in which the above-mentioned midpoint M is located radially inward of the rotation center C of the variable nozzle vane 16, it is possible to suppress the influence of the fixed vane 22 on the flow in the exhaust gas passage 24 on the turbine wheel 2, and suppress a decrease in turbine efficiency.

[0037] Furthermore, the trailing edge 22TE of the fixed vane 22 is located at a position outside the rotation center C of the variable nozzle vane 16 in the radial direction of the first annular member 12, or at the same position as the rotation center C of the variable nozzle vane 16 in the radial direction of the first annular member 12. Therefore, the effect of the fixed vane 22 on the flow in the exhaust gas passage 24 on the turbine wheel 2 can be suppressed more effectively than when the trailing edge 22TE of the fixed vane 22 is located radially inside the rotation center C of the variable nozzle vane 16, and a decrease in turbine efficiency can be suppressed.

[0038] FIG. 3 is a schematic cross-sectional view showing an example of the cross section BB of the variable nozzle device 8 shown in FIG. In some embodiments, for example as shown in FIG. 3, the fixed vane 22 may be integrally formed with the first annular member 12 so as to protrude from a surface 12a of the first annular member 12 facing the exhaust gas flow passage 24 (a surface of the first annular member 12 facing the second annular member 14) toward the second annular member 14.

[0039] In the example shown in FIG. 3, one end side of the support pin 15 is inserted into a through hole 36 formed in the first annular member 12 and is fixed to the first annular member 12 by being pressed into the through hole 36 or the like. The other end side of the support pin 15 is inserted into a through hole 38 formed in the second annular member 14 and is fixed to the second annular member 14 by being pressed into the through hole 38 or the like. The support pin 15 includes a cylindrical abutment portion 15a that abuts against the first annular member 12 in the axial direction, a cylindrical abutment portion 15b that abuts against the second annular member 14 in the axial direction, and a cylindrical main body portion 15c that connects the abutment portion 15a and the abutment portion 15b. The diameter of the main body portion 15c is smaller than the diameter of the abutment portion 15a and the diameter of the abutment portion 15b. Moreover, the height H1 of the fixed vane 22 in the axial direction and the height H2 of the variable nozzle vane 16 in the axial direction are each longer than the length H3 of the main body 15c in the axial direction. Note that the diameter D of the support pin 15 shown in Fig. 2 means the diameter of the main body 15c in the example shown in Fig. 3.

[0040] 3, the fixed vanes 22 protruding from the first annular member 12 can prevent the wake generated from the support pin 15 from reaching the downstream variable nozzle vane 16D. In addition, by providing the fixed vanes 22 only on the first annular member 12 out of the first annular member 12 and the second annular member 14, it is easier to control the dimensions in terms of the dimensional accuracy of the fixed vanes 22 than in the configuration shown in Fig. 5, which will be described later.

[0041] Figure 4 is a schematic cross-sectional view showing another example of the cross section BB of the variable nozzle device 8 shown in Figure 2. In the configuration shown in Figure 4, reference symbols common to the configuration shown in Figure 3 indicate the same configuration as the configuration shown in Figure 3 unless otherwise specified, and description thereof will be omitted.

[0042] In some embodiments, for example as shown in FIG. 4, the fixed vane 22 may be integrally formed with the second annular member 14 so as to protrude from a surface 14a of the second annular member 14 facing the exhaust gas flow passage 24 (a surface of the second annular member 14 facing the first annular member 12) toward the first annular member 12.

[0043] 4, the fixed vanes 22 protruding from the second annular member 14 can prevent the wake generated from the support pin 15 from reaching the downstream variable nozzle vane 16D. In addition, by providing the fixed vanes 22 only on the second annular member 14 out of the first annular member 12 and the second annular member 14, it is easier to control the dimensions in terms of the dimensional accuracy of the fixed vanes 22 than in the configuration shown in Fig. 5, which will be described later.

[0044] Figure 5 is a schematic cross-sectional view showing yet another example of the cross section BB of the variable nozzle device 8 shown in Figure 2. In the configuration shown in Figure 5, reference symbols common to the configuration shown in Figure 3 indicate the same configuration as the configuration shown in Figure 3 unless otherwise specified, and description thereof will be omitted.

[0045] In some embodiments, as shown in Fig. 5, for example, the variable nozzle device 8 includes a pair of fixed vanes 22a, 22b provided to face each other in the axial direction. In this case, the fixed vane 22a is provided integrally with the first annular member 12 so as to protrude from a surface 12a of the first annular member 12 on the exhaust gas passage 24 side toward the second annular member 14, and the fixed vane 22b is provided integrally with the second annular member 14 so as to protrude from a surface 14a of the second annular member 14 on the exhaust gas passage 24 side toward the first annular member 12. The sum (H1a+H1b) of the height H1a of the fixed vane 22a in the axial direction and the height H1b of the fixed vane 22b in the axial direction is greater than the length H3 of the main body portion 15c in the axial direction.

[0046] According to the configuration shown in FIG. 5, the fixed vanes 22a and 22b protruding from the first annular member 12 and the second annular member 14, respectively, can prevent the wake generated from the support pin 15 from reaching the downstream variable nozzle vane 16D.

[0047] Figure 6 is a schematic cross-sectional view showing yet another example of the cross section BB of the variable nozzle device 8 shown in Figure 2. In the configuration shown in Figure 6, reference symbols common to the configuration shown in Figure 3 indicate the same configuration as the configuration shown in Figure 3 unless otherwise specified, and description thereof will be omitted.

[0048] In some embodiments, for example, as shown in Fig. 6, the support pin 15 may be fixed to only one of the first annular member 12 and the second annular member 14. In the example shown in Fig. 6, one end side of the support pin 15 is inserted into a through hole 36 formed in the first annular member 12 and is fixed to the first annular member 12 by being pressed into the through hole 36 or the like. The other end side of the support pin 15 is not fixed to the second annular member 14. In this case, the second annular member 14 may be supported (fixed) to the turbine housing 4.

[0049] 6, it is possible to reduce distortion of the support pin 15 due to thermal deformation, compared to a case in which the support pin 15 is fixed to both the first annular member 12 and the second annular member 14. As a result, it is possible to reduce the thickness of the support pin 15, and to reduce the size of the wake generated by the support pin 15. Note that the port pin 15 may be fixed only to the second annular member 14 out of the first annular member 12 and the second annular member 14.

[0050] 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.

[0051] For example, in some embodiments, as shown in Fig. 7, the variable nozzle device 8 may not include the above-mentioned fixed vane 22. In the configuration shown in Fig. 7, reference numerals common to the configuration shown in Fig. 3 indicate the same configuration as the configuration shown in Fig. 3 unless otherwise specified, and description thereof will be omitted.

[0052] 7, one end of the support pin 15 is inserted into a through hole 36 formed in the first annular member 12 and is fixed to the first annular member 12 by being pressed into the through hole 36 or the like. The other end of the support pin 15 is not fixed to the second annular member 14. In this case, the second annular member 14 may be supported (fixed) by the turbine housing 4.

[0053] In this way, by fixing the support pin 15 to only one of the first annular member 12 and the second annular member 14, it is possible to reduce distortion of the support pin 15 due to thermal deformation, compared to a case in which the support pin 15 is fixed to both the first annular member 12 and the second annular member 14. As a result, the thickness of the support pin 15 can be reduced, and the size of the wake generated by the support pin 15 can be reduced.

[0054] In addition, in some of the above-described embodiments, a support pin is exemplified as an example of a spacer member provided in the exhaust gas flow passage to maintain the distance between the first annular member and the second annular member, but the shape of the spacer member is not limited to a cylindrical shape like the support pin. If the spacer member has a shape that generates a wake, the influence of the wake on the downstream variable nozzle vane can be reduced by providing the fixed vane according to the present disclosure. For example, in the example shown in FIG. 7, the support pin 15 as a spacer member is fixed to only one of the first annular member 12 and the second annular member 14, so that the thickness of the support pin 15 can be reduced as described above, and therefore the support pin 15 may be shaped like a blade. This makes it possible to reduce the size of the wake generated by the support pin 15. In this case, the blade shape may be, for example, a shape in which the cross-sectional shape perpendicular to the axial direction is along a straight line as shown in FIG. 8A, or a shape curved along a curve as shown in FIG. 8B.

[0055] The contents described in each of the above embodiments can be understood, for example, as follows.

[0056] (1) A variable nozzle device according to at least one embodiment of the present disclosure, A variable nozzle device (such as the variable nozzle device 8 described above) of a variable geometry turbocharger (such as 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 plurality of rotatable variable nozzle vanes (e.g., the above-mentioned plurality of variable nozzle vanes 16) are provided in the exhaust gas flow passage at intervals in the circumferential direction of the first annular member; a spacer member (e.g., the support pin 15 described above) provided in the exhaust gas flow passage so as to maintain a gap between the first annular member and the second annular member; The downstream side of the flow of the exhaust gas along the circumferential direction in the exhaust gas flow passage is defined as the downstream side in the circumferential direction, and the variable nozzle vane adjacent to the downstream side of the spacer member in the circumferential direction among the plurality of variable nozzle vanes is defined as a downstream variable nozzle vane (e.g., the above-mentioned downstream variable nozzle vane 16D). Then, a fixed vane (e.g., the above-mentioned fixed vane 22) fixed to a position between the spacer member and the downstream variable nozzle vane in the exhaust gas flow passage, Equipped with.

[0057] According to the variable nozzle device described in (1) above, by providing a fixed vane between the spacer member and the downstream variable nozzle vane, the fixed vane can prevent the wake generated from the spacer member from reaching the downstream variable nozzle vane. This reduces the effect of the wake and prevents the direction of the torque acting on the downstream variable nozzle vane from reversing from the open direction to the closed direction. This prevents the variable nozzle vane from closing when, for example, an actuator for rotating the variable nozzle vane fails, and reduces the risk of an excessive increase in turbine rotation speed, engine overboost, and the like.

[0058] (2) In some embodiments, in the variable nozzle device described in (1) above, A leading edge of the fixed vane (for example, the above-mentioned leading edge 22LE) is located radially outward of an outer end of the spacer member (for example, the above-mentioned outer end 15e) in the radial direction of the first annular member.

[0059] According to the variable nozzle device described above in (2), it is possible to effectively prevent the wake generated from the spacer member from reaching the downstream side variable nozzle vane.

[0060] (3) In some embodiments, in the variable nozzle device described in (1) or (2) above, A trailing edge of the fixed vane (for example, the above-mentioned trailing edge 22TE) is located radially inward of an inner end of the spacer member (for example, the above-mentioned inner end 15i) in the radial direction of the first annular member.

[0061] According to the variable nozzle device described above in (3), it is possible to effectively prevent the wake generated from the spacer member from reaching the downstream side variable nozzle vane.

[0062] (4) In some embodiments, in the variable nozzle device according to any one of (1) to (3) above, The spacer member is a cylindrical support pin (such as the support pin 15 described above), The vane length of the fixed vane (eg, the above-mentioned vane length L1) is greater than the diameter of the support pin (eg, the above-mentioned diameter D).

[0063] According to the variable nozzle device described above in (4), it is possible to effectively prevent the wake generated from the spacer member from reaching the downstream variable nozzle vane.

[0064] (5) In some embodiments, in the variable nozzle device according to any one of (1) to (4) above, The vane length of the fixed vane (for example, the above-mentioned vane length L1) is smaller than the vane length of the variable nozzle vane (for example, the above-mentioned vane length L0).

[0065] According to the variable nozzle device described in (5) above, the fixed vanes can prevent the wake generated from the spacer member from reaching the downstream variable nozzle vane downstream of the spacer member, while suppressing an increase in the flow resistance of the exhaust gas flow path caused by the fixed vanes.

[0066] (6) In some embodiments, in the variable nozzle device according to any one of (1) to (5) above, The spacer member is located outside the rotation center (for example, the above-mentioned rotation center C) of the variable nozzle vane in the radial direction of the first annular member.

[0067] According to the variable nozzle device described in (6) above, compared to a case in which the spacer member is positioned radially inward from the rotation center of the variable nozzle vane, the effect of the spacer member on the flow in the exhaust gas passage is suppressed from being exerted on the turbine wheel, and a decrease in turbine efficiency can be suppressed.

[0068] (7) In some embodiments, in the variable nozzle device according to any one of (1) to (6) above, In a cross section perpendicular to the axial direction of the first annular member (e.g., the above-mentioned AA cross section), the midpoint between the leading edge of the fixed vane and the trailing edge of the fixed vane (e.g., the above-mentioned midpoint M) is located outer than the rotation center of the variable nozzle vane (e.g., the above-mentioned rotation center C) in the radial direction of the first annular member.

[0069] According to the variable nozzle device described in (7) above, the influence of the fixed vanes on the flow in the exhaust gas passage on the turbine wheel can be suppressed, compared to when the position of the midpoint is located radially inward from the rotation center of the variable nozzle vane.

[0070] (8) In some embodiments, in the variable nozzle device according to any one of (1) to (7) above, The trailing edge of the fixed vane (e.g., the trailing edge 22TE mentioned above) is located at a position outer than the rotation center of the variable nozzle vane in the radial direction of the first annular member (e.g., the rotation center C mentioned above), or at the same position as the rotation center of the variable nozzle vane in the radial direction of the first annular member.

[0071] According to the variable nozzle device described in (8) above, the influence of the fixed vane on the flow in the exhaust gas passage can be reduced compared to when the trailing edge of the fixed vane is positioned radially inward from the rotation center of the variable nozzle vane.

[0072] (9) In some embodiments, in the variable nozzle device according to any one of (1) to (8) above, the first annular member rotatably supports the variable nozzle vane, The fixed vane is provided so as to protrude from a surface of the first annular member on the exhaust gas passage side (for example, the above-mentioned surface 12a) towards the second annular member.

[0073] According to the variable nozzle device described in (9) above, the fixed vanes protruding from the first annular member can prevent the wake generated from the spacer member from reaching the downstream variable nozzle vane. Furthermore, when the fixed vanes are provided only on the first annular member out of the first and second annular members, dimensional control is easier in terms of dimensional accuracy of the fixed vanes than in the configuration described in (11) below.

[0074] (10) In some embodiments, in the variable nozzle device according to any one of (1) to (8) above, the first annular member rotatably supports the variable nozzle vane, The fixed vane is provided so as to protrude from a surface of the second annular member on the exhaust gas passage side (for example, the above-mentioned surface 14a) toward the first annular member.

[0075] According to the variable nozzle device described in (10) above, the fixed vanes protruding from the second annular member can prevent the wake generated from the spacer member from reaching the downstream variable nozzle vane. Furthermore, when the fixed vanes are provided only on the second annular member out of the first and second annular members, dimensional control is easier in terms of dimensional accuracy of the fixed vanes than in the configuration described in (11) below.

[0076] (11) In some embodiments, in the variable nozzle device according to any one of (1) to (10) above, The variable nozzle device includes a pair of the fixed vanes (for example, the pair of fixed vanes 22a, 22b described above) that are provided opposite to each other in the axial direction of the first annular member.

[0077] According to the variable nozzle device described in (11) above, the fixed vanes protruding from each of the first annular member and the second annular member can prevent the wake generated from the spacer member from reaching the downstream variable nozzle vane.

[0078] (12) In some embodiments, in the variable nozzle device according to any one of (1) to (11) above, The spacer member is fixed to only one of the first annular member and the second annular member.

[0079] According to the variable nozzle device described in (12) above, compared to a case in which the spacer member is fixed to both the first annular member and the second annular member, it is possible to reduce distortion of the spacer member due to thermal deformation, which in turn makes it possible to reduce the thickness of the spacer member and the size of the wake generated by the spacer member.

[0080] (13) In some embodiments, in the variable nozzle device according to any one of (1) to (12) above, When the blade angle of the downstream side variable nozzle vane when fully open is taken as α and the blade angle of the fixed vane is taken as β, the relationship α-45°<β<α+45° is satisfied.

[0081] According to the variable nozzle device described in (12) above, it is possible to suppress the generation of wake from the fixed vane itself while avoiding interference between the leading edge of the downstream variable nozzle vane and the fixed vane when the downstream variable nozzle vane rotates.

[0082] (14) A variable nozzle device according to at least one embodiment of the present disclosure, A variable nozzle device (such as the variable nozzle device 8 described above) of a variable geometry turbocharger (such as 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 plurality of rotatable variable nozzle vanes (for example, the above-mentioned plurality of variable nozzle vanes 16) are provided in the exhaust gas passage at intervals in the circumferential direction of the exhaust gas passage; a spacer member (e.g., the support pin 15 described above) provided in the exhaust gas flow passage so as to maintain a gap between the first annular member and the second annular member; Equipped with The spacer member is located radially outward of the rotation center of the variable nozzle vane (e.g., the above-mentioned rotation center C) of the first annular member, is fixed to only one of the first annular member and the second annular member, and has a wing shape.

[0083] According to the variable nozzle device described in (14) above, the effect of the spacer member on the flow in the exhaust gas passage can be suppressed from being exerted on the turbine wheel, compared to a case where the spacer member is located radially inside the rotation center of the variable nozzle vane. Also, compared to a case where the spacer member is fixed to both the first annular member and the second annular member, the distortion of the spacer member during thermal deformation can be reduced. As a result, the thickness of the spacer member can be reduced, and the size of the wake generated by the spacer member can be reduced. Also, since the spacer member has a wing shape, the size of the wake generated by the spacer member can be effectively reduced.

[0084] (15) A variable geometry turbocharger according to at least one embodiment of the present disclosure includes: A variable nozzle device according to any one of (1) to (14) above; The turbine wheel; A casing (e.g., the above-mentioned turbine casing 4) that houses the turbine wheel; Equipped with.

[0085] According to the variable nozzle device described in (15) above, since the variable nozzle device described in any one of (1) to (14) above is provided, the fixed vanes can prevent the wake generated from the spacer member from reaching the downstream variable nozzle vane. This reduces the effect of the wake and prevents the direction of the torque acting on the downstream variable nozzle vane from reversing from the open direction to the closed direction. This prevents the variable nozzle vane from closing when, for example, the actuator for rotating the variable nozzle vane fails, and reduces the risk of an excessive increase in turbine rotation speed, engine overboost, and the like. [Explanation of symbols]

[0086] 2. Turbine wheel 4. Turbine casing 6 Bearing casing 8 Variable nozzle device 10 Scroll passage 12 First annular member 12a Exhaust gas flow path side 14 Second annular member 14a Exhaust gas flow path side 15 Support pin 15a,15b Contact part 15c Main body 15e outer edge 15i inner edge 16 Variable Nozzle Vane 16a Shaft 16LE leading edge 16TE trailing edge 16D Downstream variable nozzle vane 18 Lever plate 20 Drive Ring 22, 22a, 22b Fixed vane 22LE leading edge 22TE trailing edge 24 Exhaust gas flow path 30 support holes 36,38 Through holes 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 plurality of rotatable variable nozzle vanes provided in the exhaust gas flow passage at intervals in a circumferential direction of the first annular member; a spacer member provided in the exhaust gas flow passage so as to maintain a gap between the first annular member and the second annular member, the spacer member being fixed to at least one of the first annular member and the second annular member and being disposed between a pair of the variable nozzle vanes adjacent to each other in the circumferential direction; A downstream side of the flow of the exhaust gas along the circumferential direction in the exhaust gas flow passage is defined as a downstream side in the circumferential direction, and the variable nozzle vane adjacent to the downstream side of the spacer member in the circumferential direction among the plurality of variable nozzle vanes is defined as a downstream variable nozzle vane. A fixed vane is fixed to a position between the spacer member and the downstream variable nozzle vane in the exhaust gas flow passage, A variable nozzle device comprising:

2. The variable nozzle device according to claim 1 , wherein a leading edge of the fixed vane is located radially outward of an outer end of the spacer member in the radial direction of the first annular member.

3. 3 . The variable nozzle device according to claim 1 , wherein a trailing edge of the fixed vane is located radially inward of an inner end of the spacer member in the radial direction of the first annular member.

4. The spacer member is a cylindrical support pin, The variable nozzle device according to claim 1 , wherein a vane length of the fixed vane is greater than a diameter of the support pin.

5. The variable nozzle device according to claim 1 , wherein a vane length of the fixed vane is smaller than a vane length of the variable nozzle vane.

6. 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 plurality of rotatable variable nozzle vanes provided in the exhaust gas flow passage at intervals in a circumferential direction of the first annular member; a spacer member provided in the exhaust gas flow passage so as to maintain a gap between the first annular member and the second annular member; A downstream side of the flow of the exhaust gas along the circumferential direction in the exhaust gas flow passage is defined as a downstream side in the circumferential direction, and the variable nozzle vane adjacent to the downstream side of the spacer member in the circumferential direction among the plurality of variable nozzle vanes is defined as a downstream variable nozzle vane. A fixed vane is fixed to a position between the spacer member and the downstream variable nozzle vane in the exhaust gas flow passage, Equipped with A variable nozzle device, wherein the spacer member is located outwardly of a rotation center of the variable nozzle vane in a radial direction of the first annular member.

7. 7. The variable nozzle device according to claim 1, wherein in a cross section perpendicular to the axial direction of the first annular member, a midpoint between a leading edge of the fixed vane and a trailing edge of the fixed vane is located outer than a rotation center of the variable nozzle vane in a radial direction of the first annular member.

8. 8. The variable nozzle device according to claim 7, wherein the trailing edge of the fixed vane is located at a position outer than a rotation center of the variable nozzle vane in the radial direction of the first annular member, or at the same position as the rotation center of the variable nozzle vane in the radial direction of the first annular member.

9. The first annular member rotatably supports the variable nozzle vane, The variable nozzle device according to claim 1 , wherein the fixed vane is provided so as to protrude from a surface of the first annular member on a side of the exhaust gas flow passage towards the second annular member.

10. The first annular member rotatably supports the variable nozzle vane, The variable nozzle device according to claim 1 , wherein the fixed vane is provided so as to protrude from a surface of the second annular member on a side of the exhaust gas flow passage towards the first annular member.

11. The variable nozzle device according to claim 1 , further comprising a pair of the fixed vanes disposed opposite each other in an axial direction of the first annular member.

12. The variable nozzle device according to claim 1 , wherein the spacer member is fixed to only one of the first annular member and the second annular member.

13. The variable nozzle device according to any one of claims 1 to 12, wherein, when the blade angle of the downstream variable nozzle vane when fully open is α and the blade angle of the fixed vane is β, α-45°<β<α+45° is satisfied.

14. 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 plurality of rotatable variable nozzle vanes provided in the exhaust gas passage at intervals in a circumferential direction of the exhaust gas passage; a spacer member provided in the exhaust gas flow passage so as to maintain a distance between the first annular member and the second annular member; Equipped with a variable nozzle device, the spacer member being located radially outward of a rotation center of the variable nozzle vane in the first annular member, fixed to only one of the first annular member and the second annular member, and having a vane shape;

15. A variable nozzle device according to any one of claims 1 to 14; The turbine wheel; a casing that houses the turbine wheel; A variable geometry turbocharger.

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