Fixed blade device and supercharger

Abstract

This fixed blade device comprises a fixed blade unit and a disc spring. The fixed blade unit comprises: a plurality of fixed blade parts arranged at intervals in the circumferential direction of a supercharger in an exhaust gas flow passage for guiding an exhaust gas flowing through a scroll flow passage formed in a turbine housing to a turbine impeller housed in the turbine housing; and an annular plate part that supports the plurality of fixed blade parts and that includes a first surface which forms a flow passage surface on a hub side of the exhaust gas flow passage. The disc spring comprises: an inner diameter-side end part that abuts a bearing housing; an outer diameter-side end part that abuts a second surface of the plate part on the side opposite the first surface; and a first bent part that is bent, between the inner diameter-side end part and the outer diameter-side end part, more toward the bearing housing side in the axial direction of the supercharger progressing toward the outside in the radial direction of the supercharger.

Description

Fixed-wing equipment and superchargers

[0001] The present disclosure relates to a fixed-capacity type turbocharger and a fixed-wing device mounted on the turbocharger.

[0002] The turbocharger includes a nozzle mechanism that rectifies the flow of exhaust gas supplied from the scroll passage to the turbine impeller. The nozzle mechanism includes a nozzle plate and a plurality of blades supported by the nozzle plate. The blades are so-called nozzle vanes. If the turbocharger is a fixed displacement type, the plurality of blades are fixed to the nozzle plate and do not rotate.

[0003] The turbocharger includes a disc spring that biases the nozzle mechanism. For example, the disc spring of the turbocharger disclosed in Patent Document 1 biases the nozzle plate toward the turbine housing, and the plurality of vanes are pressed against the turbine housing. A nozzle mechanism including the plurality of vanes and the nozzle plate is an example of a fixed vane device.

[0004] Patent No. 5861287

[0005] If the disc spring is thermally deformed due to the temperature of the exhaust gas, the biasing force of the disc spring may decrease, which may cause the fixed wing device to become misaligned.

[0006] An object of the present disclosure is to provide a fixed wing device and a supercharger in which the amount of thermal deformation of the disc spring that biases the fixed wing unit is reduced.

[0007] a first bend portion that bends toward the bearing housing in the axial direction of the turbocharger as it moves radially outward from the turbocharger; and a first bend portion that bends toward the bearing housing in the axial direction of the turbocharger as it moves radially outward from the turbocharger. The fixed vane unit includes: a plurality of fixed vane sections that are arranged at intervals in the circumferential direction of the turbocharger in an exhaust gas flow path that guides exhaust gas flowing through a scroll flow path formed in the turbine housing to a turbine impeller housed in the turbine housing; and an annular plate section that supports the plurality of fixed vane sections, the plate section including a first surface that forms a flow path surface on the hub side of the exhaust gas flow path. The disc spring includes: an inner diameter side end that abuts against the bearing housing; an outer diameter side end that abuts against a second surface of the plate section opposite to the first surface; and a first bend portion that bends toward the bearing housing in the axial direction of the turbocharger as it moves radially outward from the turbocharger between the inner diameter side end and the outer diameter side end.

[0008] A turbocharger according to at least one embodiment of the present disclosure includes the above-mentioned fixed wing device; the turbine housing; the turbine impeller housed in the turbine housing; a rotor connected to the turbine impeller; a bearing that rotatably supports the rotor; and the bearing housing that houses the bearing.

[0009] According to the present disclosure, it is possible to provide a fixed wing device and a turbocharger in which the amount of thermal deformation of the disc spring that biases the fixed wing unit is reduced.

[0010] FIG. 5 is a schematic diagram of a supercharger according to one embodiment. FIG. 6 is a schematic partially enlarged diagram of a supercharger according to one embodiment. FIG. 7 is a partially enlarged diagram of FIG. 2. FIG. 8 is a schematic comparison diagram of a disc spring of an example and a disc spring of a comparative example. FIG. 9 is a schematic comparison diagram of analysis results. FIG. 10 is an explanatory diagram of "STEP" indicated by the horizontal axis of each graph in FIG. 5. FIG. 11 is a schematic diagram of a plate part according to one embodiment.

[0011] Several embodiments of the present disclosure will be described below with reference to the accompanying drawings. However, the dimensions, materials, shapes, and relative arrangements of components described as embodiments or shown in the drawings are merely illustrative examples and are not intended to limit the scope of the present disclosure. For example, expressions expressing relative or absolute arrangements, such as "in a certain direction," "along a certain direction," "parallel," "orthogonal," "center," "concentric," or "coaxial," not only strictly express such arrangements, but also express relative displacements with a tolerance or angle or distance to the extent that the same function is achieved. For example, expressions expressing the equality of things, such as "same," "equal," and "homogeneous," not only express strict equality, but also express tolerance or differences to the extent that the same function is achieved. For example, expressions expressing shapes such as a square or cylindrical shape not only express shapes such as a square or cylindrical shape in the strict geometric sense, but also express shapes including concave and convex portions, chamfered portions, etc., to the extent that the same effect is achieved. On the other hand, the expressions "comprise," "include," or "have" one component are not exclusive expressions that exclude the existence of other components. Note that similar components may be assigned the same reference numerals and descriptions thereof may be omitted.

[0012] <Overview of Turbocharger 1> Fig. 1 is a schematic diagram of a turbocharger 1 according to an embodiment of the present disclosure. The turbocharger 1 includes a turbine 2, a compressor 4, and a rotor 8 connected to the turbine 2 and the compressor 4. The turbine 2 is configured to rotate using exhaust gas emitted by an internal combustion engine mounted on, for example, an automobile as a working medium. The compressor 4 is configured to generate compressed air using the rotational force of the turbine 2 obtained via the rotor 8 as a power source. The generated compressed air is sent to the internal combustion engine. The turbine 2 includes a plurality of fixed vane portions 43 for rectifying the exhaust gas flowing toward the turbine impeller 29 (see Fig. 2). The fixed vane portions 43 are so-called fixed vanes (nozzle vanes). The turbocharger 1 shown in Fig. 1 is a fixed displacement type in which the blade angle of the fixed vane portions 43 does not vary.

[0013] In the following description, the direction in which the axis of the rotor 8 extends will be referred to as the "axial direction," and the circumferential and radial directions based on the axis will sometimes be simply referred to as the "circumferential direction" and the "radial direction," respectively. In this example, the axial direction is the horizontal direction. Furthermore, the "radial outer side" is the side away from the axis of the rotor 8, and the "radial inner side" is the side approaching the axis.

[0014] 2 is a partially enlarged view of the turbocharger 1 according to one embodiment of the present disclosure. The turbocharger 1 further includes a bearing 5 that rotatably supports the turbine 2, and a bearing housing 6 that houses the bearing 5. The bearing housing 6 is located on one side of the turbine 2 in the axial direction.

[0015] An oil passage 11 and a cooling water passage 12 are formed inside the bearing housing 6. The cooling water passage 12 is located radially outward of the oil passage 11, and the cooling water flowing through the cooling water passage 12 cools a seal ring 13 (see FIG. 3). The seal ring 13 is interposed between the bearing housing 6 and the rotor 8 and functions to prevent oil supplied from the oil passage 11 to the rotor 8 from leaking from a predetermined space. The cooling prevents deterioration of the seal ring 13 over time (more specifically, a decrease in tension caused by thermal wear), allowing the seal ring 13 to maintain its sealing performance for a long period of time. In this example, the seal ring 13 is located on the other axial side of each of the bearing 5 and the cooling water passage 12.

[0016] 2, the turbine 2 includes a turbine impeller 29 connected to the rotor 8, and a turbine housing 20 that houses the turbine impeller 29. The turbine impeller 29 includes a hub 291 and a plurality of blades 292 arranged circumferentially on the outer surface of the hub 291. The turbine housing 20 is arranged to be aligned with the bearing housing 6 in the axial direction. The turbine housing 20 and the bearing housing 6 may be fixed together by a housing fastener member (not shown). The housing fastener member includes, for example, a plurality of screws extending in the axial direction.

[0017] The turbine housing 20 defines a turbine accommodating space 28 that accommodates a turbine impeller 29. Exhaust gas flowing through a scroll passage 22 formed inside the turbine housing 20 is guided to the turbine impeller 29 via an exhaust gas passage 25. Here, the exhaust gas passage 25 is a passage that connects the scroll passage 22 and the turbine accommodating space 28.

[0018] The turbine 2 further includes a fixed wing device 30. The fixed wing device 30 includes a fixed wing unit 40 disposed between the turbine housing 20 and the bearing housing 6, and a disc spring 50 that biases the fixed wing unit 40 toward the turbine housing 20.

[0019] The stator unit 40 includes a plurality of stator blades 43 arranged at intervals in the circumferential direction in the exhaust gas flow path 25, and an annular plate portion 45 that supports the plurality of stator blades 43. Each of the plurality of stator blades 43 is a so-called fixed vane and functions to straighten the exhaust gas. The circumferentially extending plate portion 45 includes a first surface 41 that forms a flow path surface on the hub 291 side of the exhaust gas flow path 25, and a second surface 42 (see FIG. 3 ) opposite the first surface 41. Each of the first surface 41 and the second surface 42 is an annular surface that extends in the circumferential direction.

[0020] As shown in Fig. 2, the disc spring 50 is annular and extends in the circumferential direction, and the axis of the disc spring 50 substantially coincides with the axis of the rotor 8. Fig. 3 shows a cross-sectional view of the upper half of the disc spring 50. As shown in the figure, the disc spring 50 includes an inner diameter side end 58, which is the end on the inside in the radial direction, and an outer diameter side end 59, which is the end on the outside in the radial direction. The inner diameter side end 58 directly abuts against the bearing housing 6 from the other side in the axial direction, and the outer diameter side end 59 directly abuts against the second surface 42 of the plate portion 45 from one side in the axial direction.

[0021] The disc spring 50 further includes a first bent portion 53 located between the outer diameter side end 59 and the inner diameter side end 58. The first bent portion 53 faces the plate portion 45 in the axial direction with a gap S therebetween. The first bent portion 53 bends toward one axial side as it moves radially outward. In other words, the first bent portion 53 bends toward the bearing housing 6 in the axial direction as it moves radially outward. The first bent portion 53 is formed over the entire circumferential length of the disc spring 50.

[0022] The disc spring 50 shown in Fig. 3 is in a deformed state. During the assembly process of the turbocharger 1, which includes the above-described process of fastening the housing fastening member, the outer diameter side end 59 is displaced from the other side to one side in the axial direction, and the disc spring 50 changes from its natural state to an elastically deformed state. That is, the outer diameter side end 59 shown in Fig. 3 biases the second surface 42 of the plate portion 45 to the other side in the axial direction (arrow A1), thereby pressing each of the multiple fixed vane portions 43 against the turbine housing 20.

[0023] According to the above configuration, when the disc spring 50 is thermally deformed such that its radial dimension increases, the bending angle of the first bent portion 53 increases, and the reaction force (restoring force) of the disc spring 50 increases. Therefore, even if the temperature of the disc spring 50 increases due to high-temperature exhaust gas, thermal deformation of the disc spring 50 is suppressed, and a decrease in the biasing force transmitted from the disc spring 50 to the plate portion 45 is suppressed. Furthermore, because the first bent portion 53 bends axially toward the bearing housing 6 as it moves radially outward, the outer diameter side end 59 can abut against the second surface 42 of the plate portion 45 at a position axially distant from the exhaust gas flow path 25. This suppresses a temperature increase of the outer diameter side end 59, further reducing the amount of thermal deformation of the disc spring 50. As described above, a fixed wing device 30 is realized in which the amount of thermal deformation of the disc spring 50 that biases the fixed wing unit 40 is reduced.

[0024] <Verification by Analysis> The results of verifying by analysis the technical advantages obtained by providing the first bent portion 53 in the disc spring 50 will be described with reference to FIGS.

[0025] FIG. 4 is a schematic diagram showing a disc spring 50 according to an embodiment of the present disclosure and a disc spring 99 as a comparative example. This figure shows a cross-sectional view of the upper half of each of the disc springs 50 and 99. The disc springs 50 and 99 are identical in terms of specifications, including spring material, plate thickness, and radial dimension, except that the comparative disc spring 99 does not have a first bent portion 53. FIG. 5 is a comparative diagram schematically showing analytical results of changes in the displacement and biasing force of the disc springs 50 and 99. The vertical axis representing the biasing force has the same scale in the two graphs arranged horizontally at the bottom of FIG. 5 , and the vertical axis representing the displacement has the same scale in the two graphs arranged horizontally at the top. The displacement represents the amount of deformation in the axial direction of the disc springs 50 and 99 (the axial direction coincides with the radial direction relative to the axis of the rotor 8 when the disc springs 50 and 99 are assembled to the turbocharger 1). The top end of the vertical axis showing the amount of displacement is 0, and the downward direction of the vertical axis is the negative direction. On the vertical axis, the smaller the value of the amount of displacement, the larger the amount of displacement of the disc springs 50, 99. Figure 6 is a table summarizing the details of the steps on the horizontal axis of the graph shown in Figure 5.

[0026] As shown in Figures 5 and 6, in the process of switching STEP from "0" to "1," a load simulating the tightening process of the turbocharger 1 is applied to the disc springs 50, 99 in the analysis. The tightening process includes the tightening of the housing fastening members (not shown) described above. The tightening process changes the disc springs 50, 99 from their natural state to a deformed state. When STEP is "1," the biasing force of the disc spring 50 is higher than the biasing force of the disc spring 99, and it can be seen that the disc spring 50 is more suitable than the disc spring 99 for fastening the fixed wing unit 40.

[0027] In the process of switching from STEP "1" to "2", an analysis is performed to release the above-mentioned fastening. This analysis simulates partial disassembly of the turbocharger 1. The reason why the displacement amounts of the disc springs 50, 99 do not return to 0 in STEP "2", which indicates the completion of the release of fastening, is because plastic deformation has occurred. The amounts of plastic deformation are approximately the same between the disc springs 50, 99, and it can be seen that the disc spring 50 is not inferior to the disc spring 99 as a component of the turbocharger 1.

[0028] In the process of switching from STEP "2" to "3", a heat distribution simulating a temperature rise caused by exhaust gas is applied to the disc springs 50, 99 in the analysis. By applying the heat distribution, the analytical thermal deformation amounts of the disc springs 50, 99 are determined. The dimension M1 indicating the thermal deformation amount of the disc spring 50 is less than one-third of the dimension M2 indicating the thermal deformation amount of the disc spring 99, and it has been confirmed that the provision of the first bent portion 53 has a significant effect of suppressing the thermal deformation of the disc spring 50. In other words, it can be seen that the thermal deformation amount of the disc spring 50 while the turbocharger 1 is actually in use is significantly reduced. Note that when STEP "3", the clamping remains released, so the biasing force is 0.

[0029] In the process of switching from STEP "3" to "4," a load simulating the tightening process is again applied in the analysis while the heat distribution is being applied. Because significant thermal deformation has already occurred in the disc spring 99 at the time of STEP "3," the biasing force in STEP "4," where the second tightening is completed, is much smaller than the biasing force in STEP "1." In contrast, in the case of the disc spring 50, although the biasing force in STEP "4" is lower than the biasing force in STEP "1," it is much larger than the biasing force of the disc spring 99 in STEP "1," and it is found that this is suitable for fixing the fixed wing unit 40.

[0030] As described above, it is understood through analysis that the disc spring 50 including the first bent portion 53 can exert a higher biasing force than the disc spring 99 as the comparative example.

[0031] <Details of the Disc Spring 50> As shown in FIG. 3 , the disc spring 50 includes an expanded diameter portion 55 that connects the first bent portion 53 and the inner diameter side end portion 58, an extending portion 56 that extends from the first bent portion 53 along the axial direction toward the bearing housing 6, and a second bent portion 54 that bends radially outward from the extending portion 56.

[0032] The expanded diameter portion 55 expands in diameter in the axial direction toward the turbine housing 20 as it extends radially outward. In a cross-sectional view of the disc spring 50, the expanded diameter portion 55 extends linearly radially outward and axially toward the turbine housing 20. The extending portion 56 faces the plate portion 45 in the radial direction with a gap T therebetween. The second bent portion 54 is connected to the end of the extending portion 56 on the bearing housing 6 side.

[0033] The outer diameter side end portion 59 protrudes radially outward from the second bent portion 54. With this configuration, the outer diameter side end portion 59 can abut against the second surface 42 of the plate portion 45 along the axial direction. This prevents the biasing force of the disc spring 50 from diverging in the radial direction, and the disc spring 50 can firmly press the stator vane unit 40 against the turbine housing 20 along the axial direction. This makes it possible to prevent the stator vane unit 40 from shifting out of position.

[0034] In some embodiments, the outer diameter side end 59 may be located on one side in the axial direction relative to the inner diameter side end 58. In other words, the outer diameter side end 59 may be located axially closer to the bearing housing 6 than the inner diameter side end 58. With this configuration, the contact position between the outer diameter side end 59 and the second surface 42 can be further separated in the axial direction from the exhaust gas flow path 25. Therefore, the temperature rise of the outer diameter side end 59 can be further suppressed, and the amount of thermal deformation of the disc spring 50 can be further reduced.

[0035] Furthermore, since the disc spring 50 includes the expanded diameter portion 55, the bearing housing 6 can be moved closer to the turbine housing 20 in the axial direction, thereby reducing design constraints in the axial direction of the bearing housing 6. For example, the cooling water flow path 12 can be moved closer to the seal ring 13 in the axial direction, allowing the seal ring 13 to be cooled more effectively.

[0036] 7 is an enlarged view of the plate portion 45 according to one embodiment of the present disclosure. The second surface 42 of the plate portion 45 has a contact surface 421 against which the outer diameter side end portion 59 of the disc spring 50 contacts, and a connecting surface 422 that connects to the outermost peripheral edge of the contact surface 421. The connecting surface 422 extends radially outward from the contact surface 421. Hereinafter, the outer peripheral surface of the outer diameter side end portion 59 that contacts the contact surface 421 may be referred to as the "outer diameter side contact surface 61."

[0037] The plate portion 45 further has a fitting surface 46 that fits with the outer peripheral surface 6 a of the bearing housing 6. The fitting surface 46 extends from the connecting surface 422 toward one side in the axial direction. In other words, the fitting surface 46 extends from the connecting surface 422 so as to move axially away from the fixed wing portion 43. The fitting surface 46 fits with the outer peripheral surface 6 a of the bearing housing 6 over the entire circumferential length of the plate portion 45.

[0038] The engagement between the outer peripheral surface 6a of the bearing housing 6 and the engagement surface 46 of the plate portion 45 prevents exhaust gas from entering the arrangement space of the outer diameter side end 59 formed between the plate portion 45 and the bearing housing 6. As a more specific example, even if exhaust gas leaks into a small gap between the plate portion 45 and the turbine housing 20 (arrow A2), the exhaust gas can be prevented from flowing to the outer diameter side end 59. This further reduces the temperature rise of the outer diameter side end 59 and the amount of thermal deformation of the disc spring 50.

[0039] The dimensional relationship of the disc spring 50 will be described with reference to Fig. 4. In Fig. 4, dimension L1 indicates a first length, which is the shortest length in the radial direction from the inner diameter side end 58 to the first bent portion 53. Dimension L2 indicates a second length, which is the shortest length in the radial direction from the inner diameter side end 58 to the outer diameter side end 59. Dimension L3 indicates a third length, which is the radial dimension of the outer diameter side contact surface 61.

[0040] In some embodiments, the first length is 50% or more and 90% or less of the second length. According to this configuration, by making the first length 90% or less of the second length, the rigidity of the portion of the expanded diameter portion 55 from the first bent portion 53 to the inner diameter side end 58 can be ensured, and deformation of the disc spring 50 due to the reaction force from the bearing housing 6 can be suppressed. Furthermore, by making the first length 50% or more of the second length, the rigidity of the portion of the disc spring 50 from the first bent portion 53 to the outer diameter side end 59 can be ensured, and the amount of thermal deformation of the disc spring 50 can be suppressed. This achieves a disc spring 50 with balanced rigidity overall.

[0041] In some embodiments, according to this configuration, the third length is 0.5% or more and 1.5% or less of the maximum outer diameter of the disc spring 50 (more specifically, the outer diameter of the outer diameter end portion 59). The outer diameter of the outer diameter end portion 59 corresponds to dimension D in FIG. 2. According to this configuration, since the third length is 0.5% or more of the outer diameter of the outer diameter end portion 59, the outer diameter side abutment surface 61 can reliably abut against the abutment surface 421 of the plate portion 45. Furthermore, since the third length is 1.5% or less of the outer diameter, the amount of heat transfer from the plate portion 45 to the outer diameter end portion 59 can be reduced. Therefore, it is possible to reliably bias the disc spring 50 against the plate portion 45 while suppressing a temperature rise in the outer diameter end portion 59.

[0042] <Summary> The contents described in the above-described embodiments can be understood, for example, as follows.

[0043] 1) A fixed vane device (30) according to at least one embodiment of the present disclosure is a fixed vane device comprising: a fixed vane unit (40) arranged between a turbine housing (20) and a bearing housing (6) of a turbocharger (1); and a disc spring (50) that biases the fixed vane unit toward the turbine housing, wherein the fixed vane unit includes: a plurality of fixed vane portions (43) arranged at intervals in the circumferential direction of the turbocharger in an exhaust gas flow path (25) for guiding exhaust gas flowing through a scroll flow path (22) formed in the turbine housing to a turbine impeller (29) accommodated in the turbine housing; and an annular plate portion (45) that supports the plurality of fixed vane portions and includes a first surface (41) that forms a flow path surface on the hub side of the exhaust gas flow path, and the disc spring includes: an inner diameter side end (58) that abuts against the bearing housing; and an outer diameter side end (59) that abuts against a second surface (42) of the plate portion opposite to the first surface. and a first bent portion (53) between the inner diameter side end portion and the outer diameter side end portion, the first bent portion (53) bending toward the bearing housing in the axial direction of the turbocharger as it moves toward the radial outside of the turbocharger.

[0044] According to the configuration 1) above, even if the temperature of the disc spring rises due to high-temperature exhaust gas, the provision of the first bent portion reduces the amount of thermal deformation of the disc spring, thereby suppressing a decrease in the biasing force transmitted from the disc spring to the plate portion. Furthermore, because the first bent portion bends axially toward the bearing housing as it moves radially outward, the outer diameter side end can abut against the second surface of the plate portion at a position axially distant from the exhaust gas flow path. This suppresses a temperature rise at the outer diameter side end, further reducing the amount of thermal deformation of the disc spring. As a result, a fixed vane device is realized in which the amount of thermal deformation of the disc spring that biases the fixed vane unit is reduced.

[0045] 2) In some embodiments, in the fixed wing device according to 1) above, the outer diameter side end portion is located closer to the bearing housing than the inner diameter side end portion in the axial direction.

[0046] According to the configuration 2), the contact position between the outer diameter end and the second surface can be further separated from the exhaust gas flow path in the axial direction, thereby further suppressing the temperature rise at the outer diameter end and further reducing the amount of thermal deformation of the disc spring.

[0047] 3) In some embodiments, in the fixed wing device described in 1) or 2) above, the disc spring further includes an expanding portion (55) that connects the first bent portion and the inner diameter side end and expands in diameter toward the turbine housing in the axial direction as it moves toward the outside in the radial direction.

[0048] According to the configuration of 3) above, the bearing housing can be moved closer to the turbine housing in the axial direction, which reduces restrictions on the design of the bearing housing in the axial direction. For example, it becomes possible to move the cooling water flow passage formed inside the bearing closer to the seal ring, which is disposed between the bearing housing and the rotor, in the axial direction.

[0049] 4) In some embodiments, in the fixed-wing device described in any one of 1) to 3) above, a first length (dimension L1) in the radial direction from the inner diameter side end to the first bent portion is 50% or more and 90% or less of a second length (dimension L2) in the radial direction from the inner diameter side end to the outer diameter side end.

[0050] According to the configuration of 4) above, by making the first length 90% or less of the second length, the rigidity of the portion of the disc spring from the first bent portion to the inner diameter end can be ensured, and deformation of the disc spring due to reaction force from the bearing housing can be suppressed. Also, by making the first length 50% or more of the second length, the rigidity of the portion of the disc spring from the first bent portion to the outer diameter end can be ensured, and the amount of thermal deformation of the disc spring can be suppressed. This achieves a disc spring with balanced rigidity overall.

[0051] 5) In some embodiments, in the fixed wing device described in any one of 1) to 4) above, the disc spring includes a reduced diameter portion (56) that reduces in diameter from the first bent portion toward the bearing housing along the axial direction, and a second bent portion (54) that bends outward from the reduced diameter portion along the radial direction, and the outer diameter side end portion protrudes from the second bent portion toward the outside in the radial direction.

[0052] According to the configuration of 5) above, the outer diameter side end can abut against the second surface of the plate portion along the axial direction. This prevents the biasing force of the disc spring from diverging in the radial direction, allowing the disc spring to firmly press the stator vane unit against the turbine housing along the axial direction. This makes it possible to prevent the stator vane unit from shifting out of position.

[0053] 6) In some embodiments, in the fixed wing device described in 5) above, the second surface of the plate portion has an abutment surface (421) that abuts against the outer diameter side end of the disc spring, and a connecting surface (422) that extends from the outermost peripheral end of the abutment surface to the outside in the radial direction, and the plate portion further has a mating surface (46) that extends from the connecting surface so as to be away from the fixed wing portion in the axial direction and mates with the outer peripheral surface (6a) of the bearing housing.

[0054] According to the configuration of 6) above, the outer peripheral surface of the bearing housing and the mating surface of the plate portion are fitted together, which prevents exhaust gas from entering the space formed between the plate portion and the bearing housing where the outer diameter side end is located, thereby further reducing the temperature rise at the outer diameter side end and the amount of thermal deformation of the disc spring.

[0055] 7) In some embodiments, the fixed wing device is as described in 6) above, wherein the outer diameter end portion has an outer diameter abutment surface (61) that abuts against the abutment surface, and a third length (dimension L3) of the outer diameter abutment surface in the radial direction is 0.5% or more and 1.5% or less of the outer diameter (dimension D) at the outer diameter end portion.

[0056] According to the configuration of 7) above, since the third length is 0.5% or more of the outer diameter at the outer diameter end, the outer diameter side abutment surface can reliably abut against the abutment surface. Furthermore, since the third length is 1.5% or less of the outer diameter, the amount of heat transfer from the plate portion to the outer diameter side end can be reduced. Therefore, it is possible to reliably bias the disc spring against the plate portion while suppressing a temperature rise at the outer diameter side end.

[0057] 8) A turbocharger (1) according to at least one embodiment of the present disclosure comprises: the fixed wing device (30) described in any one of 1) to 7) above; the turbine housing (20); the turbine impeller (29) housed in the turbine housing; a rotor (8) connected to the turbine impeller; a bearing (5) that rotatably supports the rotor; and the bearing housing (6) that houses the bearing.

[0058] The configuration 8) above provides the same technical advantages as the configuration 1).

[0059] DESCRIPTION OF SYMBOLS 1: Turbocharger 2: Turbine 4: Compressor 5: Bearing 6: Bearing housing 6a: Outer circumferential surface 8: Rotor 11: Oil passage 12: Cooling water passage 13: Seal ring 20: Turbine housing 22: Scroll passage 25: Exhaust gas passage 28: Turbine accommodating space 29: Turbine impeller 30: Fixed vane device 40: Fixed vane unit 41: First surface 42: Second surface 43: Fixed vane portion 45: Plate portion 46: Fitting surface 50: Disc spring 53: First bent portion 54: Second bent portion 55: Expanded diameter portion 56: Extension portion 58: Inner diameter side end portion 59: Outer diameter side end portion 61: Outer diameter side abutment surface 99: Disc spring 291: Hub 292: Blade 421: Contact surface 422: Connection surface L1, L2, L3, M1, M2: Dimensions S, T: Gap

Claims

1. A fixed vane device comprising: a fixed vane unit arranged between a turbine housing and a bearing housing of a turbocharger; and a disc spring that urges the fixed vane unit toward the turbine housing, wherein the fixed vane unit comprises: a plurality of fixed vane sections arranged at intervals in the circumferential direction of the turbocharger in an exhaust gas flow path that guides exhaust gas flowing through a scroll flow path formed in the turbine housing to a turbine impeller housed in the turbine housing; and an annular plate section that supports the plurality of fixed vane sections, the plate section including a first surface that forms a flow path surface on the hub side of the exhaust gas flow path, and the disc spring comprises: an inner diameter side end that abuts against the bearing housing; an outer diameter side end that abuts against a second surface of the plate section opposite to the first surface; and a first bent section that bends between the inner diameter side end and the outer diameter side end so as to bend toward the bearing housing in the axial direction of the turbocharger as it moves radially outward of the turbocharger.

2. The fixed-wing device according to claim 1, wherein the outer diameter side end is located closer to the bearing housing than the inner diameter side end in the axial direction.

3. A fixed-wing device as described in claim 1 or 2, wherein the disc spring further includes an expanding diameter portion that is connected to the first bent portion and the inner diameter side end portion, and that expands in diameter toward the turbine housing in the axial direction as it moves toward the outside in the radial direction.

4. A fixed-wing device as described in claim 1 or 2, wherein a first length in the radial direction from the inner diameter end to the first bent portion is 50% or more and 90% or less of a second length in the radial direction from the inner diameter end to the outer diameter end.

5. A fixed-wing device as described in claim 1 or 2, wherein the disc spring includes an extending portion that extends from the first bent portion along the axial direction toward the bearing housing, and a second bent portion that bends from the extending portion to the outside along the radial direction, and the outer diameter side end portion protrudes from the second bent portion toward the outside in the radial direction.

6. A fixed wing device as described in claim 5, wherein the second surface of the plate portion has an abutment surface that abuts against the outer diameter side end of the disc spring, and a connecting surface that extends from the outermost peripheral end of the abutment surface to the outside in the radial direction, and the plate portion further has a fitting surface that extends from the connecting surface so as to be away from the fixed wing portion in the axial direction and that fits with the outer peripheral surface of the bearing housing.

7. The fixed-wing device according to claim 6, wherein the outer diameter end portion has an outer diameter side abutment surface that abuts against the abutment surface, and a third length in the radial direction of the outer diameter side abutment surface is not less than 0.5% and not more than 1.5% of the outer diameter at the outer diameter side end portion.

8. A turbocharger comprising: a fixed-wing device according to claim 1 or 2; the turbine housing; the turbine impeller housed in the turbine housing; a rotor connected to the turbine impeller; a bearing that rotatably supports the rotor; and the bearing housing that houses the bearing.

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