Valve device, turbine, and supercharger

Abstract

This valve device comprises a valve body and a valve rod for rotating the valve body around a valve shaft. The valve body includes: a seat part that includes a seat surface that can be connected to and separated from a communication port made to communicate with a merging flow path and an exhaust flow path, and can open and close the communication port; and a valve umbrella part that protrudes from the seat part toward the merging flow path and is able to divide the merging flow path into two branch flow paths. Hollow parts are formed in the radial direction inside the seat part and the valve umbrella part. The valve rod includes a valve body support part that is accommodated in the hollow part of the valve body and in which an annular slanting section is formed between the valve rod and the valve body in order to support the valve body so that the valve body can slant with respect to the valve body support part. The valve device comprises a support member disposed on the slanting section and configured to be capable of abutting a first surface of the valve body facing the slanting section and a second surface of the valve body support part facing the slanting section.

Description

Valve gear, turbine and supercharger

[0001] The present disclosure relates to a valve device, a turbine including the valve device, and a turbocharger including the turbine.

[0002] Some double-scroll turbine housings are formed with a first branch passage branching from a first scroll passage, a second branch passage branching from a second scroll passage, and a confluence passage where the first branch passage and the second branch passage join and communicates with an exhaust passage through which exhaust gas that has passed through the turbine wheel flows (see Patent Document 1).The double-scroll turbine housing described in Patent Document 1 discloses a valve that can close a communication port provided between the confluence passage and the exhaust passage and has a valve body that can separate the first branch passage and the second branch passage in the confluence passage.

[0003] International Publication No. 2019 / 190662

[0004] When the valve disc is set to an intermediate opening greater than the fully closed position, the valve disc is subjected to a load that pushes the valve disc toward the exhaust flow path and a lateral load due to the pressure difference between the two branch flow paths. Because the direction of the lateral load changes over time, the valve disc may be vibrated laterally (perpendicular to the axial direction). When the valve disc is vibrated laterally, fretting wear may occur at the contact point between the bottom of the valve disc and the disc support portion, which is the portion of the valve stem that supports the valve disc. Furthermore, there is a risk of collision between the portions of the valve disc and the disc support portion that form a radial gap, generating abnormal noise.

[0005] The invention described in Patent Document 1 discloses that a spring element that biases the valve element support portion toward the bottom of the valve element along the axial direction of the valve element suppresses relative movement between the valve element and the valve element support portion. The spring element generates frictional force that acts as a resistance to loads due to lateral forces, but there is a risk that the spring element may inhibit tilting of the valve element relative to the valve element support portion. Furthermore, there is a risk that the spring element will lose its effect of suppressing lateral vibration of the valve element when the spring wears out.

[0006] In view of the above circumstances, at least one embodiment of the present disclosure aims to provide a valve device, a turbine, and a turbocharger that can suppress collision at an inclination margin between a valve body and a valve body support portion that supports the valve body.

[0007] a valve device according to at least one embodiment of the present disclosure, the valve device having two scroll passages for guiding gas to a turbine wheel, the two scroll passages being formed in the same region in the axial direction of the turbine, the valve device being mounted on a turbine housing that rotatably accommodates the turbine wheel, the valve device comprising: a valve element for opening and closing the confluent passage where two branch passages branching from the two scroll passages respectively join, the confluent passage communicating via a communication port with an exhaust passage through which gas that has passed through the turbine wheel flows; and a valve rod for rotating the valve element around a valve axis, the valve element including: a seat portion having a seat surface that is movable toward and away from the communication port and that is capable of opening and closing the communication port; and a valve head portion that protrudes from the seat portion toward the confluent passage and is capable of dividing the two branch passages in the confluent passage, hollow portions are formed radially inwardly of the seat portion and the valve head portion, and the valve rod includes: a valve element support portion accommodated in the hollow portion of the valve element, the valve element support portion having an annular inclination margin formed between the valve element and the valve element for supporting the valve element so that it can incline relative to the valve element support portion, The valve device further includes a support member that is disposed on the inclined margin and configured to be able to abut against a first surface of the valve body facing the inclined margin and a second surface of the valve body support portion facing the inclined margin.

[0008] A turbine according to at least one embodiment of the present disclosure comprises: the valve device; the turbine wheel; and the turbine housing.

[0009] A supercharger according to at least one embodiment of the present disclosure includes the turbine.

[0010] According to at least one embodiment of the present disclosure, there are provided a valve device, a turbine, and a supercharger that can suppress collision at an inclination margin between a valve disc and a valve disc support portion that supports the valve disc.

[0011] FIG. 1 is a schematic configuration diagram of an internal combustion engine system including a turbocharger according to an embodiment of the present disclosure; FIG. 1 is a schematic cross-sectional view schematically showing a cross section perpendicular to the central axis of a turbine wheel of a turbine according to an embodiment of the present disclosure; FIG. 2 is a schematic cross-sectional view schematically showing a cross section along the central axis of a turbine housing in which a valve device according to an embodiment of the present disclosure is mounted, the cross-sectional view being taken along the central axis of the valve device according to an embodiment of the present disclosure; FIG. 3 is a schematic cross-sectional view along the central axis of the valve device according to an embodiment of the present disclosure; FIG. 4 is a schematic cross-sectional view along the central axis of the valve device according to an embodiment of the present disclosure; FIG. 5 is a schematic cross-sectional view along the central axis of the valve device according to an embodiment of the present disclosure; FIG. 6 is an explanatory view illustrating a support member according to an embodiment of the present disclosure and a mounting groove to which the support member is attached; FIG. 7 is an explanatory view illustrating a support member according to an embodiment of the present disclosure and a mounting groove to which the support member is attached; FIG. 8 is an explanatory view illustrating a support member according to an embodiment of the present disclosure and a mounting groove to which the support member is attached; FIG. 9 is a schematic cross-sectional view along the central axis of the valve device according to an embodiment of the present disclosure; 1 is a schematic view of a valve device according to an embodiment of the present disclosure, viewed from one axial side thereof, an explanatory view for explaining a support member and a recess to which the support member is attached in an embodiment of the present disclosure, and an explanatory view for explaining a support member and a recess to which the support member is attached in an embodiment of the present disclosure.

[0012] Hereinafter, several 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 embodiments or shown in the drawings are merely illustrative examples and are not intended to limit the scope of the present disclosure.

[0013] (Turbocharger) FIG. 1 is a schematic configuration diagram of an internal combustion engine system 1 including a turbocharger 2 according to an embodiment of the present disclosure. A turbine 21 according to the present disclosure can be mounted on a turbocharger 2 for, for example, an automobile, a ship, or an industry (for example, for land-based power generation). In the following embodiments, a turbine 21 mounted on a turbocharger 2 will be described as an example, but the turbine 21 according to the present disclosure is not limited to being mounted on a turbocharger 2. Furthermore, the working fluid of the turbine 21 does not need to be limited to exhaust gas. In other words, the turbine 21 according to the present disclosure may be configured as a standalone turbine 21 or may be configured in combination with a mechanism or device other than the compressor 22 as long as it is capable of converting working fluid energy into mechanical power (for example, rotational force). Furthermore, the use of the turbine 21 does not need to be limited.

[0014] 1, a turbocharger 2 according to some embodiments includes a turbine 21, a compressor 22, and a rotating shaft 23. The turbine 21 includes a turbine wheel 24 attached to one side of the rotating shaft 23, and a turbine housing 3 configured to rotatably house the turbine wheel 24. The compressor 22 includes an impeller 25 attached to the other side of the rotating shaft 23, and a compressor housing 26 configured to rotatably house the impeller 25.

[0015] The turbocharger 2 includes a bearing 27 configured to rotatably support the rotating shaft 23 between the turbine wheel 24 and the impeller 25. The turbocharger 2 may include a bearing housing 28 configured to house the bearing 27.

[0016] The turbine 21 is configured to rotate a turbine wheel 24 using the energy of exhaust gas discharged from the internal combustion engine (engine) 11. The impeller 25 is coaxially connected to the turbine wheel 24 via a rotating shaft 23, and therefore rotates in conjunction with the rotation of the turbine wheel 24. The compressor 22 is configured to rotate the impeller 25 to draw combustion gas (e.g., air) into the compressor 22, compress the combustion gas, and guide the compressed combustion gas to the internal combustion engine 11. The combustion gas guided from the compressor 22 to the internal combustion engine 11 is used for combustion in the internal combustion engine 11. The exhaust gas generated by combustion in the internal combustion engine 11 is guided from the internal combustion engine 11 to the turbine 21, causing the turbine wheel 24 to rotate.

[0017] In the illustrated embodiment, the turbine wheel 24 is configured to guide the exhaust gas introduced from the outside in the radial direction of the turbine wheel 24 along the axial direction of the turbine wheel 24. The impeller 25 is configured to guide the combustion gas introduced along the axial direction of the impeller 25 to the outside in the radial direction of the impeller 25.

[0018] (Turbine Housing) Fig. 2 is a schematic cross-sectional view that schematically shows a cross section perpendicular to the central axis LA of the turbine wheel 24 of the turbine 21 according to an embodiment of the present disclosure. Fig. 3 is a schematic cross-sectional view that schematically shows a cross section of a turbine housing 3 in which a valve device 4 according to an embodiment of the present disclosure is mounted, taken along the central axis LB of the valve device 4. Hereinafter, the direction in which the central axis LA of the turbine wheel 24 extends when the turbine wheel 24 is housed in the turbine housing 3 is defined as the axial direction of the turbine wheel 24 (turbine 21). The direction in which the central axis LB of the valve disc 5 of the valve device 4 extends when the valve device 4 is housed in the turbine housing 3 is defined as the axial direction of the valve disc 5 (valve device 4).

[0019] As shown in Fig. 2, the turbine housing 3 includes a scroll passage forming portion 31 that forms a first scroll passage 311 and a second scroll passage 312. As shown in Fig. 3, the turbine housing 3 also includes a connection passage forming portion 32 that forms a connection passage 320 that includes a first branch passage 321, a second branch passage 322, and a merging passage 323. An exhaust passage 331 through which exhaust gas flows after passing through the first scroll passage 311, the second scroll passage 312, the connection passage 320, and the turbine wheel 24 is formed inside the turbine housing 3. The turbine housing 3 is made of a metal material.

[0020] (First scroll passage, second scroll passage) As shown in Fig. 2 , each of the first scroll passage 311 and the second scroll passage 312 is a passage for introducing exhaust gas into the nozzle passage 34 of the turbine housing 3. The nozzle passage 34 is provided downstream of the first scroll passage 311 and the second scroll passage 312 in the exhaust gas passage through which exhaust gas discharged from the internal combustion engine 11 flows. The nozzle passage 34 is composed of an annular space formed inside the turbine housing 3 and radially outside the turbine wheel 24. Each of the first scroll passage 311 and the second scroll passage 312 is provided radially outside the nozzle passage 34 and is composed of a spiral passage extending in the circumferential direction around the central axis LA.

[0021] The second scroll passage 312 is formed in the same region in the axial direction of the turbine 21 as the first scroll passage 311. Note that "formed in the same region in the axial direction of the turbine 21" means that the scroll shapes of the first scroll passage 311 and the second scroll passage 312 are displayed together in a cross section perpendicular to the central axis LA of the turbine wheel 24, as shown in FIG.

[0022] 2 , the turbine housing 3 is configured so that a first range CR1 of the nozzle flow passage 34, into which exhaust gas flowing through the first scroll flow passage 311 is introduced, and a second range CR2 of the nozzle flow passage 34, into which exhaust gas flowing through the second scroll flow passage 312 is introduced, do not overlap in the circumferential direction about the central axis LA of the turbine wheel 24. In the illustrated embodiment, the second scroll flow passage 312 is provided on the outer circumferential side of the first scroll flow passage 311 (outside in the radial direction of the turbine wheel 24) in a cross section perpendicular to the central axis LA of the turbine wheel 24, and the first scroll flow passage 311 and the second scroll flow passage 312 at least partially overlap in the circumferential direction of the turbine wheel 24. Note that the first scroll flow passage 311 and the second scroll flow passage 312 may also be configured so as not to overlap in the circumferential direction of the turbine wheel 24.

[0023] The exhaust gas discharged from the internal combustion engine 11 and guided to the turbine 21 flows through the first scroll passage 311 or the second scroll passage 312 and is guided to the turbine wheel 24 through the nozzle passage 34. The exhaust gas guided to the turbine wheel 24 is discharged to the outside of the turbine 21 through the exhaust passage 331.

[0024] (First Branch Channel, Second Branch Channel, and Converging Channel) As shown in FIG. 3 , the first branch channel 321 is a channel branching from the first scroll channel 311. One end of the first branch channel 321 is connected to the first scroll channel 311 so that exhaust gas can flow therethrough, and the other end is connected to the converging channel 323 so that exhaust gas can flow therethrough. The second branch channel 322 is a channel branching from the second scroll channel 312. As shown in FIG. 3 , one end of the second branch channel 322 is connected to the second scroll channel 312 so that exhaust gas can flow therethrough, and the other end is connected to the converging channel 323 so that exhaust gas can flow therethrough. The first branch channel 321 and the second branch channel 322 are converged at the converging channel 323. The converging channel 323 is in communication with the exhaust channel 331 via a communication port 332. As a result, each of the first branch flow path 321 and the second branch flow path 322 communicates with the other branch flow path 322 , 321 and the exhaust flow path 331 via the junction flow path 323 so that exhaust gas can flow therethrough.

[0025] 3, the turbine 21 according to some embodiments includes a valve device 4 attached to the turbine housing 3. The valve device 4 includes a valve element 5 for opening and closing the above-described junction flow path 323, and a valve stem 6 for rotating the valve element 5 about a valve axis LC. The valve axis LC is the central axis of the valve stem 6.

[0026] (Valve Disk) The valve disc 5 includes a seat portion 51 and a valve head portion 52. The seat portion 51 includes a seat surface 511 that can approach and separate from the communication port 332, allowing the communication port 332 to be opened and closed. In the illustrated embodiment, the seat portion 51 has an annular disk shape including the seat surface 511 that extends in a direction perpendicular to the central axis LB of the valve disc 5 (valve device 4). The valve head portion 52 protrudes from the seat portion 51 toward the merging flow path 323. The valve head portion 52 is configured to separate two branch flow paths (the first branch flow path 321 and the second branch flow path 322) in the merging flow path 323. The valve head portion 52 has a convex shape that protrudes in a direction away from the seat surface 511 (toward the merging flow path 323) in the extension direction of the central axis LB of the valve disc 5. A hollow portion 53 is formed in the valve disc 5 radially inward of the seat portion 51 and the valve head portion 52.

[0027] The valve device 4 is configured to be able to adjust the aperture of the valve element 5. Specifically, the valve device 4 further includes a rotation drive device including an actuator (not shown) for rotating the valve stem 6 about the valve axis LC. The valve device 4 can adjust the aperture of the valve element 5 to an aperture corresponding to the angular position in the circumferential direction of the valve axis LC by rotating the valve stem 6 and the valve element 5 connected to the valve stem 6 about the valve axis LC. The valve device 4 is configured to be able to adjust the aperture of the valve element 5 to a fully open position, a fully closed position, or at least one intermediate position between the fully open and fully closed positions.

[0028] The second scroll passage 312 is connected to a cylinder different from the cylinder connected to the first scroll passage 311. The phases of exhaust pulsations of the cylinder connected to the first scroll passage 311 and the cylinder connected to the second scroll passage 312 are out of phase with each other. In the extremely low rotation speed range and the low rotation speed range of the internal combustion engine 11, either the first scroll passage 311 or the second scroll passage 312 can guide all of the exhaust gas discharged from the internal combustion engine 11 to the nozzle passage 34, so the opening of the valve element 5 is fully closed. When the opening of the valve element 5 is fully closed, the valve head portion 52 of the valve element 5 blocks the junction passage 323, narrowing the gap between the valve head portion 52 and the junction passage 323, thereby suppressing the SCV flow, i.e., the flow from either the first branch passage 321 or the second branch passage 322 to the other. Furthermore, when the valve element 5 is fully closed, the seat surface 511 of the valve element 5 abuts against the seat abutment surface 324 of the connection-flow-path forming portion 32. The seat abutment surface 324 is a surface that is connected to the communication port 332, extends in a direction perpendicular to the central axis LD of the communication port 332, and faces the exhaust flow path 331. The abutment between the seat surface 511 and the seat abutment surface 324 blocks the space between the junction flow path 323 and the exhaust flow path 331, thereby suppressing a bypass flow (WG flow) in which exhaust gas bypasses the turbine wheel 24 and is introduced from the junction flow path 323 into the exhaust flow path 331.

[0029] In the medium rotation range of the internal combustion engine 11, the flow rate of exhaust gas discharged from the internal combustion engine 11 is higher than in the low rotation range, and it becomes difficult to guide all of the exhaust gas discharged from the internal combustion engine 11 to the nozzle flow path 34 using only either the first scroll passage 311 or the second scroll passage 312. For this reason, the opening degree of the valve element 5 is set to a first intermediate opening degree that is larger than the fully closed position, thereby generating the above-mentioned SCV flow and sending excess exhaust gas from one of the first scroll passage 311 or the second scroll passage 312 to the other.

[0030] In the high rotation speed range of the internal combustion engine 11, even if the SCV flow is increased, it becomes difficult for the first scroll passage 311 and the second scroll passage 312 to guide all of the exhaust gas discharged from the internal combustion engine 11 to the nozzle passage 34. For this reason, the opening of the valve element 5 is set to a second intermediate opening degree larger than the first intermediate opening degree or to full opening, thereby increasing the bypass flow described above and sending excess exhaust gas from the first scroll passage 311 and the second scroll passage 312 to the exhaust passage 331. Note that a small amount of bypass flow may be generated when the opening of the valve element 5 is set to the first intermediate opening degree.

[0031] 4 to 6 are schematic cross-sectional views taken along the central axis LB of the valve device 4 according to an embodiment of the present disclosure. As shown in FIGS. 4 to 6, the valve stem 6 includes a valve element support portion 61 housed in the hollow portion 53 of the valve element 5. The valve element support portion 61 is connected to a valve stem main body 60 having a valve stem LC, and is rotatable together with the valve stem main body 60 about the valve stem LC. The valve element support portion 61 is formed in a cylindrical shape extending along the axial direction of the valve element 5.

[0032] (Slope, First Surface, Second Surface) In order for the valve device 4 to function as a valve that suppresses the SCV flow and the WG flow, the valve element 5 needs to be able to tilt relative to the valve element support portion 61 so that the seat surface 511 can be intimately attached to the seat abutment surface 324 when the valve element 5 is fully closed. The valve element support portion 61 is configured to form a slope 62 between itself and the valve element 5 to support the valve element 5 so that it can tilt relative to the valve element support portion 61. The slope 62 is an annular gap extending in the circumferential direction about the central axis LB of the valve element 5. The valve element 5 has a first surface 54 facing the slope 62. The valve element support portion 61 has a second surface 63 facing the slope 62. The second surface 63 faces the first surface 54 across the slope 62, which is a radial gap.

[0033] As shown in Figures 4 to 6, the valve element 5 includes a center rod portion 55 that extends from a bottom portion 521 facing the hollow portion 53 of the valve head portion 52 toward a direction away from the merging flow path 323 (the lower side in Figures 4 to 6, the side toward which the seat portion 51 is located in the axial direction). The center rod portion 55 extends along the axial direction of the valve element 5 and is adapted to be loosely inserted into the valve element support portion 61. An annular radial gap 62B is formed between an outer peripheral surface 552 of the center rod portion 55 and an inner peripheral surface 613 of the valve element support portion 61.

[0034] 4 to 6, the valve element support portion 61 includes a flange portion 64 that extends radially outward of the valve element 5 further than other portions of the valve element support portion 61. An annular radial gap 62A is formed between an outer peripheral surface 641 of the flange portion 64 and the inner peripheral surfaces 512, 523 of the seat portion 51 and the valve head portion 52.

[0035] (Prevention member) The valve device 4 is provided with an annular prevention member 8 attached to the outer periphery of a protrusion 551 that protrudes from the valve element support portion 61 of the center rod portion 55. The prevention member 8 is fixed by welding, crimping, or the like to a small diameter portion formed on the protrusion 551. By fixing the prevention member 8 to the protrusion 551, movement of the valve element support portion 61 in the axial direction of the valve element 5 is restricted, and the valve element support portion 61 is prevented from coming off the center rod portion 55.

[0036] When the valve disc 5 is set to the first intermediate opening degree, which is greater than the fully closed position, the valve disc 5 is subjected to a load F1 that pushes the valve disc 5 upward toward the exhaust flow path 331, and a load F2 due to a lateral force caused by a pressure difference between the two branch flow paths 321 and 322. The direction of the load F2 due to the lateral force changes over time, and the valve disc 5 may be vibrated laterally (in a direction perpendicular to the axial direction). When the valve disc 5 is vibrated laterally, fretting wear may occur at the contact area between the bottom 521 of the valve disc 5 and the valve disc support portion 61, and the portions of the valve disc 5 and the valve disc support portion 61 that form the radial gaps 62A and 62B may collide with each other, generating abnormal noise.

[0037] (Support Member) As shown in FIGS. 4 to 6 , the above-described valve device 4 includes a support member 7 disposed on the inclined margin 62. The support member 7 is configured to be able to abut against the first surface 54 of the valve element 5, which faces the inclined margin 62, and the second surface 63 of the valve element support portion 61, which faces the inclined margin 62. The term "configured so that the support member 7 can abut against the first surface 54 and the second surface 63" does not necessarily mean that the support member 7 abuts against both the first surface 54 and the second surface 63, but also means that there is a relatively small gap (a gap smaller than the radial gaps 62A, 62B) between the support member 7 and the first surface 54 or the second surface 63, and the support member 7 abuts against both the first surface 54 and the second surface 63 when a load F2 due to a lateral force acts on the support member 7. In this case, the load F2 due to the lateral force can be supported by the support member 7 disposed on the inclined margin 62, effectively suppressing relative movement between the valve element 5 and the valve element support portion 61 in the lateral direction (a direction perpendicular to the axial direction). This makes it possible to suppress collisions between the valve element 5 and the valve element support portion 61 that supports the valve element 5 in radial gaps 62A, 62B such as the inclined margin 62.

[0038] 4 and 6 , the inclined margin 62 in which the support member 7 is disposed corresponds to the radial gap 62A. The first surface 54 corresponds to the inner circumferential surfaces 512, 523 (inner circumferential surface 512 in the illustrated example) of the seat portion 51 or the valve head portion 52, and the second surface 63 corresponds to the outer circumferential surface 641 of the flange portion 64. The load F2 due to the lateral force acts on the seat portion 51 and the valve head portion 52 (particularly the valve head portion 52) of the valve disc 5. Therefore, by disposing the support member 7 between the inner circumferential surfaces 512, 523 of the seat portion 51 or the valve head portion 52, on which the load F2 due to the lateral force acts, and the outer circumferential surface 641 of the flange portion 64, the load F2 due to the lateral force can be quickly supported by the support member 7.

[0039] 5, the inclined margin 62 in which the support member 7 is disposed is the radial gap 62B. The first surface 54 is the outer peripheral surface 552 of the center rod portion 55, and the second surface 63 is the inner peripheral surface 613 of the valve body support portion 61. The support member 7 disposed in the radial gap 62B can be made relatively smaller in size than when the support member 7 is disposed in the radial gap 62A.

[0040] In the embodiment shown in FIGS. 4 and 5 , the bottom surface 522 of the bottom portion 521 of the valve head portion 52 and the end surface 612 of the axial end portion 611 of the valve element support portion 61 abutting against the bottom surface 522 each have an inclined surface such that the radial distance from the central axis LB increases toward the direction away from the merging flow channel 323 (the lower side in FIGS. 4 to 6 , the side toward which the seat portion 51 is located in the axial direction). These inclined surfaces may be curved surfaces having a predetermined radius of curvature. The valve device 4 has such an inclined surface, which makes it easy to incline the valve element 5 relative to the valve element support portion 61. As shown in FIG. 6 , the bottom surface 522A of the bottom portion 521 of the valve head portion 52 and the end surface 612A of the axial end portion 611 of the valve element support portion 61 abutting against the bottom surface 522A each may have a flat surface extending in a direction perpendicular to the axial direction of the valve element 5.

[0041] (Metal O-ring) Each of Figures 7 to 9 is an explanatory diagram illustrating a support member 7 and an attachment groove to which the support member 7 is attached according to an embodiment of the present disclosure. In some embodiments, as shown in Figures 4 to 9, an attachment groove 41 extending along the circumferential direction is formed in the first surface 54 or the second surface 63. The support member 7 extends along the circumferential direction and is attached to the attachment groove 41. A portion of the support member 7 protrudes outside the attachment groove 41. By attaching the support member 7 to the attachment groove 41, the support member 7 can be supported by the valve body 5 or the valve body support portion 61, thereby improving the ease of assembly of the valve device 4 compared to when the attachment groove 41 is not formed in the first surface 54 or the second surface 63.

[0042] 4 and 6, the mounting groove 41 is an annular groove formed in the outer peripheral surface 641 of the flange portion 64, which is the second surface 63, and extends in the circumferential direction. In the embodiment shown in Fig. 5, the mounting groove 41 is an annular groove formed in the outer peripheral surface 552 of the center rod portion 55, which is the first surface 54, and extends in the circumferential direction. Note that the mounting groove 41 may be formed in the inner peripheral surfaces 512, 523 of the seat portion 51 or the valve head portion 52, or may be formed in the inner peripheral surface 613 of the valve element support portion 61.

[0043] In the embodiment shown in Figures 4 to 9, the support member 7 is an endless annular member (metal O-ring) 71 extending in the circumferential direction. The annular member 71 is made of metal, and has a circular or elliptical cross section along the axial direction of the valve body 5 (transverse cross section of the annular member 71). By making the cross section along the axial direction of the annular member 71 (support member 7) circular or elliptical and making the contact portion with the first surface 54 or the second surface 63 of the support member 7 a line contact, it is possible to reduce malfunctions caused by shape mismatch of the support member 7 with the first surface 54 or the second surface 63, and to prevent the support member 7 from interfering with the tilt of the valve body 5 relative to the valve body support portion 61.

[0044] In the embodiment shown in Figures 4 to 7, the mounting groove 41 is a rectangular groove that, in a cross section along the axial direction of the valve body 5 (transverse cross section of the mounting groove 41), includes a bottom surface 411 that is aligned with the axial direction of the valve body 5, a first groove wall surface 412 that extends radially outward from one axial end of the bottom surface 411 along the radial direction, and a second groove wall surface 413 that extends radially outward from the other axial end of the bottom surface 411 along the radial direction.

[0045] In the embodiment shown in Figures 8 and 9, the mounting groove 41 has a V-shaped cross section (transverse cross section of the mounting groove 41) along the axial direction of the valve disc 5. Specifically, the mounting groove 41 includes a first groove inclined surface 414 whose depth increases toward one side (lower side in the figure) in the axial direction of the valve disc 5, and a second groove inclined surface 415 whose depth increases toward the other side (upper side in the figure) in the axial direction of the valve disc 5. The second groove inclined surface 415 is formed closer to the one side (lower side in the figure) in the axial direction of the valve disc 5 than the first groove inclined surface 414. By making the axial cross section of the mounting groove 41 V-shaped, the insertion of the support member 7 into the mounting groove 41 can be simplified compared to when the cross section is rectangular.

[0046] In the embodiment shown in FIG. 9 , the surface 641 on which the mounting groove 41 is formed includes a tapered surface 641A that slopes such that the inclined margin 62 increases with increasing axial distance from the edge 416 of the mounting groove 41. The inclined margin 62 increases in axial direction, meaning that the tapered surface 641A slopes such that the radial distance from the central axis LB decreases. By providing the tapered surface 641A on the surface 641 on which the mounting groove 41 is formed, the support member 7 can be fitted into the mounting groove 41 by sliding along the tapered surface 641A. This simplifies the insertion of the support member 7 into the mounting groove 41 compared to when the tapered surface 641A is not provided. The tapered surface 641A is formed upstream of the mounting groove 41 in the mounting direction of the support member 7 (lower in the figure).

[0047] (Modification of Support Member) Figure 10 is a schematic cross-sectional view taken along the central axis LB of the valve device 4 according to an embodiment of the present disclosure. Figures 11 and 12 are explanatory views illustrating a support member 7 according to an embodiment of the present disclosure. In the embodiment shown in Figures 10 to 12, the support member 7 described above is an arc-shaped member 72 extending in the circumferential direction from one arc-shaped end 721 to the other arc-shaped end 722. In the embodiment shown in Figure 10, the arc-shaped member 72 has a rectangular cross section (transverse cross section of the arc-shaped member 72) taken along the axial direction of the valve body 5, and is attached to the mounting groove 41.

[0048] 11 , the arc-shaped member 72 has a wrap angle θ (see FIG. 12 , the circumferential angle from one arc end 721 to the other arc end 722) that is less than 360°, and an opening 723 is formed between the one arc end 721 and the other arc end 722. The wrap angle θ of the arc-shaped member 72 is preferably equal to or greater than 330° and less than 360°.

[0049] As shown in Fig. 12, the arc-shaped member 72 may have a wrap angle θ greater than 360°. In the embodiment shown in Fig. 12, the arc-shaped member 72 is a double-wrapped ring whose wrap angle θ satisfies the condition of 720°±10°.

[0050] (Sealing Member) Figure 13 is a schematic cross-sectional view taken along the central axis LB of the valve device 4 according to an embodiment of the present disclosure. In the embodiment shown in Figure 13, the support member 7 is a sealing member 73. The sealing member 73 is disposed in contact with each of the first surface 54 and the second surface 63, and is configured to be able to expand and contract along the radial direction of the valve body 5. In this case, the sealing member 73 can be deflected when the valve body 5 is tilted relative to the valve body support portion 61, and therefore the sealing member 73 can be prevented from interfering with the tilting of the valve body 5 relative to the valve body support portion 61.

[0051] 13 , the seal member 73 has a U-shape or V-shape in cross section along the axial direction of the valve disc 5, with an opening on one side in the axial direction. The seal member 73 includes a side portion 731 abutting against the first surface 54, a side portion 732 abutting against the second surface 63, and a connecting portion 733 connecting one axial end of the side portion 731 to one axial end of the side portion 732. In this case, when the valve disc 5 is tilted relative to the valve disc support portion 61, the seal member 73 can be deflected relatively greatly in the radial direction of the valve disc 5, thereby effectively preventing the seal member 73 from interfering with the tilt of the valve disc 5 relative to the valve disc support portion 61.

[0052] (Spherical bodies) Figure 14 is a schematic cross-sectional view taken along the central axis LB of the valve device 4 according to an embodiment of the present disclosure. Figures 15 and 16 are each a schematic view of the valve device 4 as viewed from one side in the axial direction. Figures 17 and 18 are explanatory views illustrating the support member 7 and the recess 42 to which the support member 7 is attached according to an embodiment of the present disclosure. In the embodiment shown in Figures 14 to 17, the seal member 73 is a plurality of spherical bodies 74 arranged on the inclined margin 62. The plurality of spherical bodies 74 are arranged at intervals in the circumferential direction of the valve body 5.

[0053] 14 and 15, each of the plurality of spherical bodies 74 is mounted in the above-described mounting groove 41. In the embodiment shown in Figures 14 and 15, a retainer (cage) 75 is mounted in the mounting groove 41 between two spherical bodies 74 arranged adjacent to each other in the circumferential direction, thereby preventing the spherical bodies 74 from shifting in the circumferential direction.

[0054] 16 to 18, a plurality of recesses 42 into which the spherical bodies 74 are attached are formed in the first surface 54 or the second surface 63 (in the illustrated example, the outer peripheral surface 641 of the flange portion 64). The recesses 42 are formed at positions spaced apart in the circumferential direction of the valve body 5. Each of the plurality of spherical bodies 74 is attached to a corresponding recess 42, thereby preventing the spherical bodies 74 from shifting in the circumferential direction.

[0055] By making the support member 7 a spherical body 74 that is mounted in the mounting groove 41 or the recess 42, and making the contact portion of the support member 7 with the first surface 54 or the second surface 63 a point contact, malfunctions caused by shape mismatch of the support member 7 with the first surface 54 or the second surface 63 can be reduced, and the support member 7 can be effectively prevented from interfering with the inclination of the valve body 5 relative to the valve body support portion 61.

[0056] In some embodiments, the recess 42 described above has a longitudinal direction along the axial direction of the valve disc 5, as shown in Figures 17 and 18. The recess 42 is configured to allow the spherical body 74 attached to the recess 42 to roll along the axial direction of the valve disc 5. As shown in Figure 17, when the diameter of the spherical body 74 is defined as D and the axial length of the recess 42 over which the spherical body 74 can roll is defined as L, it is preferable that the axial length L satisfies the condition 1.5 x D ≤ L ≤ 2 x D. By allowing the spherical body 74 to roll along the axial direction of the valve disc 5 within the recess 42, it is possible to effectively prevent the support member 7 from interfering with the inclination of the valve disc 5 relative to the valve disc support portion 61.

[0057] A turbine 21 according to some embodiments includes the above-described valve device 4, the above-described turbine wheel 24, and the above-described turbine housing 3. A turbocharger 2 according to some embodiments includes the above-described turbine 21. The turbine 21 and the turbocharger 2 including the valve device 4 can suppress collision at the inclined margin 62 between the valve disc 5 and the valve disc support portion 61 that supports the valve disc 5, and therefore can suppress the generation of abnormal noise due to the collision.

[0058] In this specification, 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 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 expressing that things are in an equal state, such as "identical," "equal," and "homogeneous," not only express a state in which there is a strict equivalence, but also express a state in which there is a tolerance or a difference to the extent that the same function is obtained. Furthermore, in this specification, expressions expressing shapes such as a rectangular shape or a cylindrical shape not only express shapes such as a rectangular shape or a 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 obtained. Furthermore, in this specification, the expressions "comprise," "include," or "have" a component are not exclusive expressions that exclude the presence of other components.

[0059] The present disclosure is not limited to the above-described embodiment, and includes modifications of the above-described embodiment and appropriate combinations of these modifications. For example, a support member 7 other than the annular member 71 may be disposed in the radial gap 62B.

[0060] The contents of the above-described embodiments can be understood, for example, as follows.

[0061] 1) A valve device (4) according to at least one embodiment of the present disclosure is a valve device (4) having two scroll passages (311, 312) for guiding gas to a turbine wheel (24), the two scroll passages (311, 312) being formed in the same region in the axial direction of a turbine (21), the valve device (4) being mounted on a turbine housing (3) that rotatably accommodates the turbine wheel (24), the valve device (4) comprising: a confluent passage (323) at which two branch passages (321, 322) branching off from the two scroll passages (311, 312), respectively, converge, the confluent passage (323) communicating with an exhaust passage (331) through which gas that has passed through the turbine wheel (24) flows; a valve element (5) for opening and closing the confluent passage (323) that communicates with the exhaust passage (331) through a communication port (332); and a valve rod (6) for rotating the valve element (5) around a valve axis, the valve element (5) comprising: a seat portion (51) including a seat surface (511) that is movable toward and away from the communication port (332) and that is capable of opening and closing the communication port (332); and a valve head portion (52) that protrudes from the seat portion (51) toward the junction flow path (323) and is capable of separating the two branch flow paths (321, 322) in the junction flow path (323), wherein a hollow portion (53) is formed radially inside the seat portion (51) and the valve head portion (52), and the valve stem (6) includes a valve element support portion (61) that is housed in the hollow portion (53) of the valve element (5), and an annular inclination margin (62) is formed between the valve element (5) and the valve element support portion (61) for supporting the valve element (5) so that the valve element (5) can be inclined relative to the valve element support portion (61), and the valve device (4) The valve body further includes a support member (7) that is arranged on the inclined margin (62) and configured to be able to abut against a first surface (54) of the valve body (5) that faces the inclined margin (62) and a second surface (63) of the valve body support portion (61) that faces the inclined margin (62).

[0062] According to the configuration of 1) above, the load (F2) due to the lateral force caused by the pressure difference between the two branch flow paths (321, 322) can be supported by the support member (7) arranged on the inclined margin (62), and the relative movement between the valve disc (5) and the valve disc support portion (61) in the lateral direction (direction perpendicular to the axial direction) can be effectively suppressed. This makes it possible to suppress collision in the radial gap, such as the inclined margin (62), between the valve disc (5) and the valve disc support portion (61) that supports the valve disc (5).

[0063] 2) In some embodiments, in the valve device (4) described in 1) above, a mounting groove (41) extending along a circumferential direction is formed in the first surface (54) or the second surface (63), and the support member (7) extends along the circumferential direction and is attached to the mounting groove (41).

[0064] According to the configuration of 2) above, by attaching the support member (7) to the mounting groove (41), the support member (7) can be supported on the valve body (5) or the valve body support portion (61). This improves the ease of assembly of the valve device (4) compared to a case where the mounting groove (41) is not formed on the first surface (54) or the second surface (63).

[0065] 3) In some embodiments, in the valve device (4) described in 2) above, the support member (7) is an annular member (71) extending along the circumferential direction, and the surface (641) on which the mounting groove (41) is formed includes a tapered surface (641A) that is inclined such that the inclination margin (62) increases as the surface becomes more distant from the edge (416) of the mounting groove (41) in the axial direction.

[0066] According to the configuration of 3) above, by providing a tapered surface (641A) on the surface (641) on which the mounting groove (41) is formed, the support member (7) can be attached to the mounting groove (41) by sliding it along the tapered surface (641A), which simplifies the insertion of the support member (7) into the mounting groove (41) compared to when the tapered surface (641A) is not provided.

[0067] 4) In some embodiments, the valve device (4) is as described in 2) or 3) above, wherein the support member (7, 71) has a circular or elliptical cross section along the axial direction.

[0068] According to the configuration of 4) above, by making the cross section of the support member (7, 71) along the axial direction circular or elliptical and making the contact portion with the first surface (54) or the second surface (63) of the support member (7) a line contact, it is possible to reduce malfunctions caused by shape mismatch of the support member (7) with the first surface (54) or the second surface (63), and to prevent the support member (7) from interfering with the inclination of the valve body (5) relative to the valve body support portion (61).

[0069] 5) In some embodiments, in the valve device (4) described in 2) or 3) above, the mounting groove (41) has a V-shaped cross section along the axial direction.

[0070] According to the configuration of 5) above, by making the cross section of the mounting groove (41) along the axial direction V-shaped, the insertion of the support member (7) into the mounting groove (41) can be simplified compared to when the cross section is rectangular.

[0071] 6) In some embodiments, in the valve device (4) described in 1) above, the support member (7) includes a sealing member (73) that is arranged in contact with each of the first surface (54) and the second surface (63) and is configured to be expandable and contractible along the radial direction.

[0072] According to the configuration of 6) above, the seal member (73) can be deflected when the valve body (5) is tilted relative to the valve body support portion (61), and therefore, the seal member (73) can be prevented from interfering with the tilt of the valve body (5) relative to the valve body support portion (61).

[0073] 7) In some embodiments, the valve device (4) described in 6) above, wherein the seal member (73) has a U-shape or V-shape in cross section along the axial direction with an opening on one side in the axial direction.

[0074] According to the configuration of 7) above, when the valve body (5) is tilted relative to the valve body support portion (61), the sealing member (73) can be deflected relatively greatly in the radial direction of the valve body (5), so that it is possible to effectively prevent the sealing member (73) from interfering with the tilt of the valve body (5) relative to the valve body support portion (61).

[0075] 8) In some embodiments, in the valve device (4) described in 1) above, the support member (7) includes a plurality of spherical bodies (74) arranged at intervals in the circumferential direction of the inclined margin (62), and recesses (42) into which the spherical bodies (74) are attached are formed in the first surface (54) or the second surface (63).

[0076] According to the configuration of 8) above, the support member (7) is made into a spherical body (74) mounted in the recess (42), and the contact portion of the support member (7) with the first surface (54) or the second surface (63) is made into a point contact, thereby reducing malfunctions caused by shape mismatch of the support member (7) with the first surface (54) or the second surface (63), and effectively preventing the support member (7) from interfering with the inclination of the valve body (5) with respect to the valve body support portion (61).

[0077] 9) In some embodiments, the valve device (4) described in 8) above, wherein the recess (42) has a longitudinal direction along the axial direction, and the spherical body (74) attached to the recess (42) is configured to be able to roll along the axial direction.

[0078] According to the configuration of 9) above, by allowing the spherical body (74) to roll in the axial direction within the recess (42), it is possible to effectively prevent the support member (7) from interfering with the inclination of the valve body (5) relative to the valve body support portion (61).

[0079] 10) In some embodiments, in the valve device (4) described in any one of 1) to 9) above, the valve body (5) includes a center stem portion (55) extending from a bottom portion (521) of the valve head portion (52) in a direction away from the merging flow path (323), the valve body support portion (61) includes a flange portion (64) extending radially outward, the first surface (54) is an inner peripheral surface (512, 523) of the seat portion (51) or the valve head portion (52), and the second surface (63) is an outer peripheral surface (641) of the flange portion (64).

[0080] According to the configuration of 10), the load (F2) due to the lateral force caused by the pressure difference occurring between the two branch flow paths (321, 322) acts on the seat portion (51) and the valve head portion (52) of the valve disc (5). Therefore, by disposing the support member (7) between the inner peripheral surface (512, 523) of the seat portion (51) or the valve head portion (52) on which the load (F2) due to the lateral force acts and the outer peripheral surface (641) of the flange portion (64), the load (F2) due to the lateral force can be quickly supported by the support member (7).

[0081] 11) In some embodiments, in the valve device (4) described in any one of 1) to 9) above, the valve body (5) includes a center stem portion (55) extending from the bottom (521) of the valve head portion (52) in a direction away from the merging flow path (323), the first surface (54) is an outer peripheral surface (552) of the center stem portion (55), and the second surface (63) is an inner peripheral surface (613) of the valve body support portion (61).

[0082] According to the configuration of 11) above, the support member (7) arranged between the outer peripheral surface (552) of the center rod portion (55) and the inner peripheral surface (613) of the valve body support portion (61) can be made relatively small in size.

[0083] 12) A turbine (21) according to at least one embodiment of the present disclosure comprises: the valve device (4) described in any one of 1) to 11); the turbine wheel (24); and the turbine housing (3).

[0084] According to the configuration of 12), the turbine (21) equipped with the valve device (4) can suppress collision of the valve element (5) with the valve element support portion (61) supporting the valve element (5) at the inclined margin (62), thereby suppressing the generation of abnormal noise due to the collision.

[0085] 13) A turbocharger (2) according to at least one embodiment of the present disclosure includes the turbine (21) described in 12) above.

[0086] According to the configuration of 13), the turbocharger (2) including the valve device (4) can suppress collision of the valve disc (5) with the valve disc support portion (61) supporting the valve disc (5) at the inclined margin (62), and therefore can suppress the generation of abnormal noise due to the collision.

[0087] REFERENCE SIGNS LIST 1 Internal combustion engine system 2 Turbocharger 3 Turbine housing 4 Valve device 5 Valve disc 6 Valve stem 7 Support member 8 Anti-detachment member 11 Internal combustion engine 21 Turbine 22 Compressor 23 Rotating shaft 24 Turbine wheel 25 Impeller 26 Compressor housing 27 Bearing 28 Bearing housing 31 Scroll passage forming portion 32 Connection passage forming portion 34 Nozzle passage 41 Mounting groove 42 Recess 51 Seat portion 52 Valve head portion 53 Hollow portion 54 First surface 55 Center stem portion 60 Valve stem main body portion 61 Valve disc support portion 62 Inclined margin 62A, 62B Radial gap 63 Second surface 64 Flange portion 71 Annular member 72 Arc-shaped member 73 Seal member 74 Spherical body 311 First scroll passage 312 Second scroll flow path 321 First branch flow path 322 Second branch flow path 323 Merging flow path 331 Exhaust flow path 332 Communication port

Claims

1. A valve device having two scroll passages for guiding gas to a turbine wheel, the two scroll passages being formed in the same region in the axial direction of the turbine, and mounted on a turbine housing that rotatably accommodates the turbine wheel, the valve device comprising: a confluent passage where two branch passages branching from the two scroll passages respectively join, the confluent passage communicating via a communication port with an exhaust passage through which gas that has passed through the turbine wheel flows; a valve element for opening and closing the confluent passage; and a valve rod for rotating the valve element around a valve axis, the valve element including a seat portion that has a seat surface that can be brought into contact with and separated from the communication port and is capable of opening and closing the communication port; and a valve head portion that protrudes from the seat portion toward the confluent passage and is capable of separating the two branch passages in the confluent passage, hollow portions are formed radially inward of the seat portion and the valve head portion, and the valve rod includes: a valve element support portion that is accommodated in the hollow portion of the valve element, the valve element support portion having an annular inclination margin formed between the valve element and the valve element to support the valve element so that it can be tilted relative to the valve element support portion, the valve device The valve device further includes a support member that is disposed on the inclined margin and configured to be able to abut against a first surface of the valve body that faces the inclined margin and a second surface of the valve body support portion that faces the inclined margin.

2. The valve device according to claim 1, wherein a mounting groove extending along a circumferential direction is formed on the first surface or the second surface, and the support member extends along the circumferential direction and is attached to the mounting groove.

3. A valve device as set forth in claim 2, wherein the support member is an annular member extending in the circumferential direction, and the surface on which the mounting groove is formed includes a tapered surface that is inclined so that the inclination margin increases with increasing distance from the edge of the mounting groove in the axial direction.

4. The valve device according to claim 2 or 3, wherein the support member has a circular or elliptical cross section along the axial direction.

5. The valve device according to claim 4, wherein the mounting groove has a V-shaped cross section along the axial direction.

6. The valve device according to claim 1, wherein the support member includes a seal member that is arranged in contact with each of the first surface and the second surface and is configured to be expandable and contractible along the radial direction.

7. The valve device according to claim 6, wherein the seal member has a U-shaped or V-shaped cross section along the axial direction with an opening on one side in the axial direction.

8. The valve device according to claim 1, wherein the support member includes a plurality of spherical bodies arranged at intervals in the circumferential direction of the inclined margin, and the first surface or the second surface is formed with recesses into which the spherical bodies are attached.

9. The valve device according to claim 8, wherein the recess has a longitudinal direction along the axial direction, and the spherical body attached to the recess is configured to be able to roll along the axial direction.

10. A valve device as set forth in any one of claims 1 to 3 and 6 to 9, wherein the valve body includes a center stem portion extending from the bottom of the valve head portion in a direction away from the merging flow path, the valve body support portion includes a flange portion extending radially outward, the first surface is the inner peripheral surface of the seat portion or the valve head portion, and the second surface is the outer peripheral surface of the flange portion.

11. A valve device as set forth in any one of claims 1 to 3 and 6 to 9, wherein the valve body includes a center stem portion extending from the bottom of the valve head portion in a direction away from the merging flow path, the first surface is the outer peripheral surface of the center stem portion, and the second surface is the inner peripheral surface of the valve body support portion.

12. A turbine comprising: the valve device according to any one of claims 1 to 3 and 6 to 9; the turbine wheel; and the turbine housing.

13. A turbocharger comprising the turbine according to claim 12.

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