Turbine and turbocharger

Abstract

The turbine (T) is provided, comprising: a turbine impeller; a plurality of nozzle vanes (113) positioned on a radially outer side with respect to the turbine impeller, spaced apart from one another in a circumferential direction of the turbine impeller, and each being pivotable about a pivot axis extending along an axial direction of the turbine impeller; a first annular component (cover band ring 101) and a second annular component extending in the circumferential direction and sandwiching the plurality of nozzle vanes (113) from both sides in the axial direction; and at least one groove (121) formed in a surface (surface 101d) opposite the plurality of nozzle vanes (113) in at least one of the first annular component or the second annular component, extending in a direction inclined with respect to the circumferential direction.

Description

Technical field

[0001] The present disclosure relates to a turbine and a turbocharger. The present application claims the effect of the priority of Japanese patent application No. 2023-145938, which was filed on September 8, 2023, and the contents of which are incorporated herein by reference. Technical background

[0002] In a turbine used for a turbocharger or the like, a nozzle vane is sometimes provided to adjust the flow velocity of an exhaust gas. For example, as disclosed in patent literature 1, a plurality of nozzle vanes are placed on a radially outer side with respect to a turbine impeller, spaced apart from one another in a circumferential direction of the turbine impeller. The cross-sectional area of ​​a flow passage formed between adjacent nozzle vanes changes as each nozzle vane pivots. In this way, the flow velocity of the exhaust gas flowing between the adjacent nozzle vanes changes. List of patent literature

[0003] Patent Literature 1: JP 2004-116313 A Summary Technical Problem

[0004] Each nozzle blade is sandwiched between two annular components in one axial direction of the turbine impeller. In some cases, a foreign substance can penetrate the space between the nozzle blade and the annular component. Such ingress can impede the smooth operation of the nozzle blade.

[0005] One of the objectives of the present disclosure is to provide a turbine and a turbocharger capable of removing a foreign substance. Solution to the problem

[0006] To solve the aforementioned problem, a turbine is provided according to the present disclosure, comprising: a turbine impeller; a plurality of nozzle vanes positioned on a radially outer side with respect to the turbine impeller, spaced apart from one another in a circumferential direction of the turbine impeller, and each being pivotable about a pivot axis extending along an axial direction of the turbine impeller; a first annular component and a second annular component extending in the circumferential direction and sandwiching the plurality of nozzle vanes from both sides in the axial direction; and at least one groove formed in a surface opposite the plurality of nozzle vanes in at least one of the first annular component or the second annular component, extending in a direction inclined with respect to the circumferential direction.

[0007] From an axial perspective, at least one groove can extend along an outer edge of a corresponding plurality of nozzle vanes if an opening degree of the corresponding plurality of nozzle vanes is a specific opening degree.

[0008] From an axial perspective, at least one groove can intersect a corresponding plurality of nozzle vanes, regardless of the degree of opening of the corresponding plurality of nozzle vanes.

[0009] At least one groove can extend from an inner circumferential edge to an outer circumferential edge of the surface.

[0010] The turbine can further have a third annular component, which is provided on one side opposite the plurality of nozzle vanes with respect to the second annular component, extends in the circumferential direction, and is designed to be pivotable in conjunction with the plurality of nozzle vanes. The at least one groove can be formed in at least the first annular component.

[0011] The turbine may further have a third annular component, which is provided on one side opposite the plurality of nozzle vanes with respect to the second annular component, extends in the circumferential direction, and is designed to be pivotable in conjunction with the plurality of nozzle vanes. The at least one groove may be provided in at least the second annular component.

[0012] To solve the aforementioned problem, a turbocharger is provided according to the present disclosure, which has the aforementioned turbine. Advantageous effects of the invention

[0013] According to the present disclosure, a foreign substance can be removed. Brief description of the drawings Fig. Figure 1 is a schematic cross-sectional view of a turbocharger according to an embodiment of the present disclosure. Fig. 2 is a view of a first region, which is from Fig. 1 is taken from. Fig. Figure 3 is a view of a drive ring in the exemplary embodiment from the perspective of a bearing housing side. Fig. 4 is a view of a second region, which is from Fig. 1 is taken from. Fig. Figure 5 is a view of a cover band ring in the exemplary embodiment from the bearing housing side. Fig. Figure 6 is a view of a cover band ring in a modification example from the bearing housing side. Description of exemplary implementations

[0014] An embodiment of the present disclosure will now be described with reference to the accompanying drawings.

[0015] Dimensions, materials, and other specific numerical values ​​shown in the exemplary embodiment are merely examples to facilitate understanding and do not limit the present disclosure unless otherwise specified. In this description and the drawings, elements that have essentially the same functions and configurations are designated with the same reference numerals, thus eliminating redundant descriptions of them. Furthermore, representations of elements not directly related to this disclosure have been omitted.

[0016] Fig. Figure 1 is a schematic cross-sectional view of a turbocharger TC according to this embodiment. The following description assumes a direction indicated by the arrow L, which points in Fig. Figure 1 corresponds to the left side of the turbocharger TC. A description is given assuming a direction indicated by the arrow R, which points in Fig. Figure 1 shows the right side of the turbocharger TC. As shown in Fig. As shown in Figure 1, the turbocharger TC has a turbocharger main body 1. The turbocharger main body 1 has a bearing housing 3, a turbine housing 5 and a compressor housing 7.

[0017] The turbine housing 5 is coupled to a left side of the bearing housing 3 by a fastening bolt 9. The compressor housing 7 is coupled to a right side of the bearing housing 3 by a fastening bolt 11. The turbocharger TC has a turbine T and a centrifugal compressor C. The turbine T has the bearing housing 3 and the turbine housing 5. The centrifugal compressor C has the bearing housing 3 and the compressor housing 7.

[0018] A bearing bore 3a is formed in the bearing housing 3. The bearing bore 3a extends through the bearing housing 3 in a left-right direction of the turbocharger TC. A bearing 13 is positioned in the bearing bore 3a. Fig. Figure 1 shows a semi-floating bearing as an example of bearing 13. However, bearing 13 can be a different type of bearing, such as a fully floating bearing or a rolling bearing. Bearing 13 axially supports a shaft 15 in a rotatable manner. A turbine impeller 17 is provided at a left end section of the shaft 15. The turbine impeller 17 is housed in the turbine casing 5 to allow rotation. A compressor impeller 19 is provided at a right end section of the shaft 15. The compressor impeller 19 is housed in the compressor casing 7 to allow rotation. The turbine impeller 17 and the compressor impeller 19 rotate integrally with the shaft 15.

[0019] The axial direction, radial direction, and circumferential direction of the turbocharger TC are hereinafter also referred to simply as an "axial direction," a "radial direction," and a "circumferential direction," respectively. The axial direction of the turbocharger TC corresponds to an axial direction of the shaft 15, an axial direction of the turbine impeller 17, and an axial direction of the compressor impeller 19. The radial direction of the turbocharger TC corresponds to a radial direction of the shaft 15, a radial direction of the turbine impeller 17, and a radial direction of the compressor impeller 19. The circumferential direction of the turbocharger TC corresponds to a circumferential direction of the shaft 15, a circumferential direction of the turbine impeller 17, and a circumferential direction of the compressor impeller 19.

[0020] An intake port 21 is formed in the compressor housing 7. The intake port 21 opens on the right side of the turbocharger TC. The intake port 21 is connected to an air filter (not shown). A diffuser flow passage 23 is formed between the bearing housing 3 and the compressor housing 7. The diffuser flow passage 23 increases the air pressure. The diffuser flow passage 23 extends circumferentially and is annular in shape. The diffuser flow passage 23 communicates with the intake port 21 on a radially inner side via a space in which the compressor impeller 19 is located.

[0021] A compressor screw flow passage 25 is formed in the compressor housing 7. The compressor screw flow passage 25 extends circumferentially and is annular in shape. The compressor screw flow passage 25 is located, for example, on a radially outer side with respect to the compressor impeller 19. The compressor screw flow passage 25 is connected to an intake port of a machine (not shown) and the diffuser flow passage 23.

[0022] When the compressor impeller 19 rotates, air is drawn into the compressor housing 7 from the intake port 21. The drawn-in air is pressurized and accelerated as it flows through the blades of the compressor impeller 19. The pressure of the pressurized and accelerated air is increased in the diffuser flow passage 23 and the compressor screw flow passage 25. The pressurized air flows out of a discharge port (not shown) and is directed to the intake port of the machine.

[0023] An outlet port 27 is formed in the turbine housing 5. The outlet port 27 opens on the left side of the turbocharger TC. The outlet port 27 is connected to an exhaust gas cleaning device (not shown). A free space 29 is formed between the bearing housing 3 and the turbine housing 5. A flow passage 31, through which exhaust gas flows, is formed in the free space 29. The flow passage 31 extends circumferentially and is annular in shape.

[0024] A turbine screw flow passage 33 is formed in the turbine housing 5. The turbine screw flow passage 33 is located, for example, on the radially outer side with respect to the turbine runner 17. The flow passage 31 is located between the turbine runner 17 and the turbine screw flow passage 33. The flow passage 31 allows the turbine screw flow passage 33 and the outlet port 27 to communicate with each other via a space in which the turbine runner 17 is located.

[0025] The turbine screw flow passage 33 is connected to a gas inlet port (not shown). Exhaust gas discharged from an exhaust gas distributor in the machine (not shown) is routed to the gas inlet port. The exhaust gas, having been routed from the gas inlet port to the turbine screw flow passage 33, is then directed to the outlet port 27 via the flow passage 31 and the blades of the turbine runner 17. The exhaust gas flowing to the outlet port 27 causes the turbine runner 17 to rotate.

[0026] The rotational force of the turbine impeller 17 is transmitted to the compressor impeller 19 via the shaft 15. As described above, the air pressure is increased by the rotational force of the compressor impeller 19, and the air is directed to the machine's intake port.

[0027] If the flow rate of the exhaust gas introduced into the turbine housing 5 decreases, the rotational speed of the turbine impeller 17 also decreases. If the rotational speed of the turbine impeller 17 decreases, the rotational speed of the compressor impeller 19 also decreases. If the rotational speed of the compressor impeller 19 decreases, it may not be possible to sufficiently increase the pressure of the air supplied to the machine's intake port.

[0028] A variable capacity mechanism 100 is provided in the free space 29 of the turbine housing 5. The variable capacity mechanism 100 changes the flow cross-sectional area of ​​the flow passage 31 depending on the exhaust gas flow rate. For example, the variable capacity mechanism 100 reduces the flow cross-sectional area of ​​the flow passage 31 when the machine speed is low and the exhaust gas flow rate is small.

[0029] When the cross-sectional area of ​​the flow passage 31 decreases, the flow velocity of the exhaust gas passing through the flow passage 31 increases compared to a case where the cross-sectional area of ​​the flow passage 31 is large. As the exhaust gas flow velocity increases, the rotational speed of the turbine impeller 17 increases. As the rotational speed of the turbine impeller 17 increases, so does the rotational speed of the compressor impeller 19. With the increased rotational speed of the compressor impeller 19, the pressure of the air supplied to the machine's intake port can be sufficiently increased. In this way, the variable capacity mechanism 100 can increase the rotational speeds of the turbine impeller 17 and the compressor impeller 19 when the exhaust gas flow rate is low.

[0030] The following describes details of the variable capacity mechanism 100.

[0031] The variable capacity mechanism 100 has a cover band ring 101, a nozzle ring 103, a retaining element 105, a drive ring 107, a transmission element 109, a connecting plate 111, a plurality of nozzle vanes 113, a drive mechanism 115, and an actuator 117. The cover band ring 101 and the nozzle ring 103 correspond to examples of a first annular component and a second annular component, respectively, which sandwich-like surround the plurality of nozzle vanes 113 from both sides in the axial direction.

[0032] The cover band ring 101 is positioned on one side of the free space 29 that is farther away from the bearing housing 3. The nozzle ring 103 is positioned on the other side of the free space 29 that is closer to the bearing housing 3. The cover band ring 101 is positioned to be opposite the nozzle ring 103 in the axial direction. The cover band ring 101 is positioned to be spaced apart from the nozzle ring 103 in the axial direction. The flow passage 31 is formed between the cover band ring 101 and the nozzle ring 103.

[0033] The cover band ring 101 has an annular shape extending in the circumferential direction. The cover band ring 101 is positioned coaxially with the turbine impeller 17. The cover band ring 101 has a main body section 101a, which has the shape of a thin, plate-like ring. The nozzle ring 103 also has an annular shape extending in the circumferential direction. The nozzle ring 103 is positioned coaxially with the turbine impeller 17. The nozzle ring 103 has a main body section 103a, which has the shape of a thin, plate-like ring.

[0034] The outer diameter of the main body section 103a of the nozzle ring 103 is approximately equal to the outer diameter of the main body section 101a of the cover band ring 101. However, the outer diameter of the main body section 103a of the nozzle ring 103 can be larger or smaller than the outer diameter of the main body section 101a of the cover band ring 101. The inner diameter of the main body section 103a of the nozzle ring 103 is larger than the inner diameter of the main body section 101a of the cover band ring 101. However, the inner diameter of the main body section 103a of the nozzle ring 103 can be equal to or smaller than the inner diameter of the main body section 101a of the cover band ring 101.

[0035] Fig. 2 is a view of a first region R1, which is from Fig. 1 is taken from. As in Fig. As shown in Figure 2, a plurality of pin-type holes 101b are formed in the main body section 101a of the cover band ring 101. Each pin-type hole 101b passes through the main body section 101a in the axial direction. The plurality of pin-type holes 101b are designed to be spaced apart from one another in the circumferential direction. For example, the plurality of pin-type holes 101b are formed at equal intervals in the circumferential direction. However, the plurality of pin-type holes 101b can also be formed at unequal intervals in the circumferential direction.

[0036] A plurality of pinholes 103b are formed in the main body section 103a of the nozzle ring 103. Each pinhole 103b passes through the main body section 103a in the axial direction. The plurality of pinholes 103b are designed to be spaced apart from one another in the circumferential direction. For example, the plurality of pinholes 103b are formed at equal intervals in the circumferential direction. However, the plurality of pinholes 103b can also be formed at unequal intervals in the circumferential direction.

[0037] The number of pin shaft holes 101b corresponds to the number of pin shaft holes 103b. Each pin shaft hole 101b is axially opposite each pin shaft hole 103b. That is, each pin shaft hole 101b is coaxial with each pin shaft hole 103b. A coupling pin 119 is inserted into the pin shaft hole 101b and the pin shaft hole 103b. The cover band ring 101 is coupled to the nozzle ring 103 by the coupling pin 119. The distance between the cover band ring 101 and the nozzle ring 103 is kept constant by the coupling pin 119.

[0038] The retaining component 105 is positioned between the nozzle ring 103 and the bearing housing 3. The retaining component 105 is coupled to the nozzle ring 103 by the coupling pin 119. In the example of Fig. In Figure 2, the retaining element 105 has two ring-shaped thin plates joined together. However, the retaining element 105 can have a single ring-shaped thin plate or it can have three or more ring-shaped thin plates joined together.

[0039] An outer circumferential edge of the retaining element 105 is sandwiched between the turbine housing 5 and the bearing housing 3. The retaining element 105 is held non-rotatably between the turbine housing 5 and the bearing housing 3. The retaining element 105 non-rotatably holds the cover band ring 101 and the nozzle ring 103. The drive ring 107 is positioned between the nozzle ring 103 and the bearing housing 3. The retaining element 105 holds the drive ring 107 in place, allowing it to rotate relatively freely.

[0040] The drive ring 107 has an annular shape extending in the circumferential direction. The drive ring 107 is positioned coaxially with the turbine impeller 17. The drive ring 107 is positioned on one side opposite the plurality of nozzle vanes 113 with respect to the nozzle ring 103. The drive ring 107 is designed to be pivotable in conjunction with the plurality of nozzle vanes 113, as will be described later. The drive ring 107 corresponds to an example of a third annular component that is positioned on one side opposite the plurality of nozzle vanes 113 with respect to the second annular component.

[0041] Fig. Figure 3 is a view of the drive ring 107 from the side of the bearing housing 3. As in Fig. As shown in Figure 3, the drive ring 107 has a main body section 107a, which is in the form of a thin, plate-like ring. An inner circumferential surface of the main body section 107a engages with an engagement claw 105a of the retaining element 105, so that the main body section 107a is held in place to be pivotable relative to the retaining element 105. A plurality of transmission element engagement sections 107b and a connecting plate engagement section 107c are formed in the main body section 107a.

[0042] The transmission element engagement section 107b is a section of the main body section 107a that is cut out from the inner circumferential surface of the main body section 107a towards the radially outer side. Multiple transmission element engagement sections 107b are formed at equal intervals in the circumferential direction of the main body section 107a. The transmission element engagement section 107b engages with an engagement end 109a of the transmission element 109.

[0043] The connecting plate engagement section 107c is a section of the main body section 107a that is cut out from the inner circumferential surface of the main body section 107a towards the radially outer side. There is one connecting plate engagement section 107c. The connecting plate engagement section 107c is formed between two transmission element engagement sections 107b that are adjacent to each other in the circumferential direction. The connecting plate engagement section 107c engages with an engagement end 111a of the connecting plate 111.

[0044] An insertion hole 109b is formed in the transmission element 109. The insertion hole 109b is formed on one side opposite the engagement end 109a in the transmission element 109. As shown in Fig. 3 and Fig. As shown in Figure 4, which will be referred to later, a blade shaft 113a of the nozzle vane 113 is inserted into the insertion hole 109b. The transmission element 109 is riveted in a state in which the blade shaft 113a of the nozzle vane 113 is inserted into the insertion hole 109b. The transmission element 109 and the nozzle vane 113 pivot integrally with the blade shaft 113a.

[0045] An insertion hole 111b is formed in the connecting plate 111. The insertion hole 111b is formed on one side opposite the engagement end 111a in the connecting plate 111. As shown in Fig. 2 and Fig. As shown in Figure 3, a pivot shaft RA of the drive mechanism 115 is inserted into the insertion hole 111b. The connecting plate 111 is riveted in such a way that the pivot shaft RA of the drive mechanism 115 is inserted into the insertion hole 111b. The connecting plate 111 pivots integrally with the pivot shaft RA of the drive mechanism 115. However, the pivot shaft RA of the drive mechanism 115 can also be welded into the insertion hole 111b of the connecting plate 111.

[0046] Fig. 4 is a view of a second region R2, which is from Fig. 1 is taken from. As in Fig. As shown in Figure 4, a plurality of blade shaft holes 101c are formed in the main body section 101a of the cover band ring 101. Each blade shaft hole 101c is formed on a radially inner side with respect to the pin shaft hole 101b in the main body section 101a. Each blade shaft hole 101c passes through the main body section 101a in the axial direction. The plurality of blade shaft holes 101c are designed to be spaced apart from one another in the circumferential direction. Specifically, the plurality of blade shaft holes 101c are formed at equal intervals in the circumferential direction.

[0047] A plurality of blade shaft holes 103c are formed in the main body section 103a of the nozzle ring 103. Each blade shaft hole 103c is formed on the radially inner side with respect to the pin shaft hole 103b in the main body section 103a. Each blade shaft hole 103c passes through the main body section 103a in the axial direction. The plurality of blade shaft holes 103c are designed to be spaced apart from one another in the circumferential direction. Specifically, the plurality of blade shaft holes 103c are formed at equal intervals in the circumferential direction.

[0048] The number of blade shaft holes 103c corresponds to the number of blade shaft holes 101c. Each blade shaft hole 103c is axially opposite each blade shaft hole 101c. That is, each blade shaft hole 103c is coaxial with each blade shaft hole 101c. The blade shaft 113a projects axially from each of the surfaces on both sides of each nozzle blade 113. Each blade shaft 113a is inserted into each of the blade shaft holes 101c and 103c. Each blade shaft 113a is rotatably supported axially by each of the blade shaft holes 101c and 103c.

[0049] The multiple nozzle vanes 113 are positioned in the flow passage 31 to be spaced apart from one another in the circumferential direction. That is, the multiple nozzle vanes 113 are positioned on the radially outer side with respect to the turbine impeller 17 to be spaced apart from one another in the circumferential direction. Specifically, the multiple nozzle vanes 113 are positioned at equal intervals in the circumferential direction. Each nozzle vane 113 is designed to pivot integrally with the blade shaft 113a about a central axis of the blade shaft 113a. That is, each nozzle vane 113 is designed to pivot about a pivot axis that extends along the axial direction of the turbine impeller 17.

[0050] As in Fig. As shown in Figure 1, the actuator 117 is located outside the turbine housing 5, the bearing housing 3, and the compressor housing 7. The actuator 117 is, for example, a solenoid. The actuator 117 is coupled to the drive mechanism 115. The drive mechanism 115 converts a linear movement of the actuator 117 into a rotary movement of the slewing shaft RA.

[0051] When the actuator 117 is driven, the pivot shaft RA of the drive mechanism 115 rotates. As the pivot shaft RA rotates, the connecting plate 111 pivots about a central axis of the pivot shaft RA, moving integrally with the pivot shaft RA. As the connecting plate 111 pivots, the connecting plate engagement section 107c is pressed circumferentially along the connecting plate 111, and the drive ring 107 pivots about a central axis of the drive ring 107. As the drive ring 107 pivots, the transmission element 109 is pressed circumferentially through the transmission element engagement section 107b and pivots about a central axis of the insertion hole 109b. When the transmission element 109 pivots, the blade shaft 113a rotates integrally with the transmission element 109. When the blade shaft 113a rotates, the nozzle vane 113 pivots integrally with the blade shaft 113a.

[0052] When each nozzle vane 113 pivots, the distance between two nozzle vanes 113 that are adjacent to each other in the circumferential direction changes. When the distance between the two nozzle vanes 113 that are adjacent to each other in the circumferential direction changes, the cross-sectional area of ​​the flow passage 31 changes. When the cross-sectional area of ​​the flow passage 31 changes, the flow velocity of the exhaust gas flowing through the flow passage 31 changes.

[0053] The variable capacity mechanism 100 changes the distance between the two circumferentially adjacent nozzle vanes 113 by causing the plurality of nozzle vanes 113 to pivot according to the exhaust gas flow rate. In this way, the degree of opening of the nozzle vane 113 changes. As the direction of extension of the nozzle vane 113 approaches the circumferential direction of the turbine impeller 17, the distance between the two circumferentially adjacent nozzle vanes 113 becomes smaller, and the degree of opening of the nozzle vane 113 decreases. In contrast, if an angle formed by the extension direction of the nozzle vane 113 and the circumferential direction of the turbine impeller 17 becomes larger, the distance between the two nozzle vanes 113 that are adjacent to each other in the circumferential direction becomes wider and the opening degree of the nozzle vane 113 becomes greater.

[0054] The opening degree of the nozzle vane 113 is adjustable within a range that has an upper and a lower limit. When the nozzle vane 113 is fully closed, its direction of extension is closest to the circumferential direction of the turbine impeller 17, and the opening degree of the nozzle vane 113 is minimal. Conversely, when the nozzle vane 113 is fully open, the angle formed by the direction of extension of the nozzle vane 113 and the circumferential direction of the turbine impeller 17 is greatest, and the opening degree of the nozzle vane 113 is maximal. As the opening degree of the nozzle vane 113 decreases, the flow passage cross-sectional area of ​​the flow passage 31 decreases.

[0055] For example, the variable capacity mechanism 100 reduces the opening degree of the nozzle vane 113 when the exhaust gas flow rate is low, thereby increasing the exhaust gas flow velocity. In this way, the variable capacity mechanism 100 can increase the rotational speed of the turbine impeller 17 even when the exhaust gas flow rate is low. As a consequence, the variable capacity mechanism 100 can also increase the rotational speed of the compressor impeller 19 even when the exhaust gas flow rate is low.

[0056] As in Fig. As shown in Figure 4, in the variable capacity mechanism 100, the plurality of nozzle vanes 113 are sandwiched together on both sides in the axial direction by the cover band ring 101, which is the first annular component, and the nozzle ring 103, which is the second annular component. A right surface 101d of the cover band ring 101 faces the plurality of nozzle vanes 113. A left surface 103d of the nozzle ring 103 faces the plurality of nozzle vanes 113.

[0057] A gap is provided between surface 101d of the cover ring 101 and the nozzle vane 113. A foreign substance can penetrate this gap. A gap is also provided between surface 103d of the nozzle ring 103 and the nozzle vane 113. A foreign substance can also penetrate this gap. Examples of foreign substances include substances originating from machine oil. A foreign substance that has penetrated the gap between the cover ring 101 or the nozzle ring 103 and the nozzle vane 113 can become a factor that impedes the smooth operation of the nozzle vane 113.

[0058] In this embodiment, a device for removing a foreign substance is applied to at least one of the cover band ring 101 or the nozzle ring 103. An example is described below in which a device for removing a foreign substance is applied to the cover band ring 101. However, as will be described later, a similar device can be applied to the nozzle ring 103.

[0059] Fig. Figure 5 is a view of the cover band ring 101 in this embodiment from the side of the bearing housing 3. Fig. 5 and Fig. Figure 6, which will be referred to later, shows that the position of the pivot axis of the nozzle vane 113 is marked by a point P1. Each nozzle vane 113 is pivotable about point P1. The point P1 corresponding to each nozzle vane 113 is located on a circle that is concentric with the central axis of the turbine impeller 17.

[0060] As described above, the degree of opening of the nozzle vane 113 changes when the nozzle vane 113 pivots. Fig. Figure 5 shows a fully closed state S1, in which the opening degree of the nozzle vane 113 is minimal, a fully open state S2, in which the opening degree of the nozzle vane 113 is maximal, and a specific state S3, in which the opening degree of the nozzle vane 113 is a specific opening degree between the minimum and maximum values. In the example of Fig. 5. The nozzle vane 113 reaches the specific state S3 by pivoting counterclockwise from the fully closed state S1. Furthermore, the nozzle vane 113 reaches the fully open state S2 by pivoting further counterclockwise from the specific state S3.

[0061] The specific opening degree in the specific state S3 is, for example, one of the most frequently used opening degrees of the nozzle vane 113. That is, during operation of the turbocharger TC, the nozzle vane 113 is in the specific state S3 in many situations.

[0062] As in Fig. As shown in Figure 5, a plurality of grooves 121, each extending in a direction inclined with respect to the circumferential direction of the turbine impeller 17, are formed in the surface 101d of the cover ring 101. The plurality of grooves 121 are designed to be spaced apart from one another in the circumferential direction. Specifically, the plurality of grooves 121 are formed at equal intervals in the circumferential direction. Each groove 121 is designed to run close to each nozzle vane 113. One groove 121 is provided for one nozzle vane 113. That is, the number of grooves 121 corresponds to the number of nozzle vanes 113. However, the number of grooves 121 can be less than or greater than the number of nozzle vanes 113. The number of grooves 121 can be one.

[0063] One possible shape of the groove 121 in a cross-section perpendicular to the direction of extension of the groove 121 is, for example, a rectangle. However, the shape of the groove 121 in the cross-section can be other than a rectangle. For example, the shape of the groove 121 in the cross-section can be a polygon, which is different from a rectangle, or it can be a semicircle.

[0064] In the example of Fig. 5 The groove 121 extends from an inner circumferential edge to an outer circumferential edge of the surface 101d of the cover band ring 101. The groove 121 is continuous with an inner circumferential surface of the cover band ring 101 at the inner circumferential edge of the surface 101d. The groove 121 is continuous with an outer circumferential surface of the cover band ring 101 at the outer circumferential edge of the surface 101d.

[0065] However, it is not required that the groove 121 extend from the inner circumferential edge to the outer circumferential edge of the surface 101d of the cover band ring 101. For example, the groove 121 may extend to the inner circumferential edge of the surface 101d of the cover band ring 101, but it need not extend to the outer circumferential edge of the surface 101d, and it need not be continuous with the outer circumferential surface of the cover band ring 101. For example, the groove 121 may extend to the outer circumferential edge of the surface 101d of the cover band ring 101, but it need not extend to the inner circumferential edge of the surface 101d, and it need not be continuous with the inner circumferential surface of the cover band ring 101.For example, the groove 121 does not have to extend to the inner circumferential edge of the surface 101d and does not have to be continuous with the inner circumferential surface of the cover band ring 101 and does not have to extend to the outer circumferential edge of the surface 101d and does not have to be continuous with the outer circumferential surface of the cover band ring 101.

[0066] In the example of Fig. 5. From the perspective of the axial direction of the turbine impeller 17, the groove 121 extends along an outer edge of the nozzle vane 113 when the opening degree of the nozzle vane 113 is the specific opening degree. That is, in the specific state S3, the groove 121 extends along the outer edge of the nozzle vane 113, from the perspective of the axial direction of the turbine impeller 17. However, it is only required that the groove 121 extends in a direction inclined with respect to the circumferential direction of the turbine impeller 17, and the groove 121 is not to be applied to the example of Fig. 5 limited.

[0067] In the example of Fig. In specific state S3, the groove 121 does not overlap the nozzle vane 113 and runs close to the nozzle vane 113, viewed in the axial direction of the turbine impeller 17. Specifically, in specific state S3, the groove 121 extends along an outer edge corresponding to a side surface on the radially outer side of the nozzle vane 113, viewed in the axial direction of the turbine impeller 17. That is, in specific state S3, the groove 121 is located on the radially outer side with respect to the nozzle vane 113. However, the groove 121 can also extend along an outer edge corresponding to a side surface on the radially inner side of the nozzle vane 113, viewed in the axial direction of the turbine impeller 17. That is, in specific state S3, the groove 121 can be located on the radially inner side with respect to the nozzle vane 113.

[0068] In the example of Fig. In section 5, the entire groove 121 has a curved shape. However, part of the groove 121 may have a straight shape, or the entire groove 121 may have a straight shape. Part of the groove 121 may be bent or curved.

[0069] As described above, in the turbine T at least one groove 121, extending in a direction inclined with respect to the circumferential direction of the turbine impeller 17, is formed in the surface 101d opposite the plurality of nozzle vanes 113 in the shroud ring 101, which is the first annular component. In this way, a foreign substance supplied to the variable capacity mechanism 100 can be guided to the groove 121, and therefore the penetration of the foreign substance into a space between the surface 101d of the shroud ring 101 and the nozzle vane 113 can be suppressed. Furthermore, the variable capacity mechanism 100 can cause the nozzle vane 113 to scrape out and remove the foreign substance that has been guided to the groove 121 by opening and closing the nozzle vane 113.In this way, the penetration of the foreign substance into the space between the surface 101d of the cover band ring 101 and the nozzle vane 113 can be suppressed more effectively.

[0070] In the example of Fig. In specific state S3, the groove 121 does not overlap the nozzle vane 113 and is located on the radially outer side with respect to the nozzle vane 113, viewed in the axial direction of the turbine impeller 17. Therefore, the variable capacity mechanism 100 can cause the nozzle vane 113 to scrape and remove the foreign material that has been led to a radially inner part of the groove 121 with respect to point P1 by causing the nozzle vane 113 to pivot clockwise from specific state S3. The variable capacity mechanism 100 can also cause the nozzle vane 113 to scrape and remove the foreign material that has been led to a radially outer part of the groove 121 with respect to point P1 by causing the nozzle vane 113 to pivot counterclockwise from specific state S3.In this way, the variable capacity mechanism 100 performs a removal process in which the nozzle vane 113 scrapes and removes the foreign material that has been led to the groove 121 by changing the degree of opening of the nozzle vane 113. For example, the variable capacity mechanism 100 can perform the removal process after the turbocharger TC has stopped.

[0071] The foregoing describes an example in which the groove 121 is formed in the cover band ring 101, which is the first annular component. However, the groove 121 can also be formed in the surface 103d opposite the plurality of nozzle vanes 113 in the nozzle ring 103, which is the second annular component. In this case as well, the foreign material that has been introduced into the groove 121 can be scraped out and removed by the nozzle vane 113 by opening and closing the nozzle vane 113. In this way, the penetration of the foreign material into a space between the surface 103d of the nozzle ring 103 and the nozzle vane 113 can be more effectively suppressed. That is to say, it is only required that the groove 121 be formed in the surface opposite the plurality of nozzle vanes 113 in at least one of the cover band ring 101 or the nozzle ring 103.

[0072] The groove 121 can be formed in either the cover band ring 101 or the nozzle ring 103. The groove 121 can also be formed in only one of the cover band ring 101 or the nozzle ring 103.

[0073] For example, the groove 121 is formed in at least the component cover band ring 101 between the components cover band ring 101, which is the first annular component, and nozzle ring 102, which is the second annular component. From the point of view of improving the efficiency of the turbine T, in some cases a gap between the surface 101d of the cover band ring 101 and the nozzle blade 113 is designed to be smaller than a gap between the surface 103d of the nozzle blade 103 and the nozzle blade 113. In these cases, the foreign matter that has penetrated the gap between the surface 101d of the cover band ring 101 and the nozzle blade 113 is more likely to accumulate and less likely to be released compared to the foreign matter that has penetrated the gap between the surface 103d of the nozzle blade 103 and the nozzle blade 113.Therefore, if the groove 121 is formed in at least the cover band ring 101, it is possible to more effectively suppress any hindrance to the smooth operation of the nozzle vane 113 by the foreign substance that has been supplied to the variable capacity mechanism 100.

[0074] For example, the groove 121 is formed in at least the nozzle ring 103 component, specifically in the first annular component and the second annular component. When the groove 121 is formed in the cover ring 101, it increases the flow rate of a leakage flow, which is a flow of exhaust gas escaping through a space between the cover ring 101 and the nozzle vane 113. Similarly, when the groove 121 is formed in the nozzle ring 103, it increases the flow rate of a leakage flow, which is a flow of exhaust gas escaping through a space between the nozzle ring 103 and the nozzle vane 113.

[0075] As described above, from the point of view of improving the efficiency of the turbine T, in some cases the free space between the surface 101d of the cover ring 101 and the nozzle blade 113 is designed to be smaller than the free space between the surface 103d of the nozzle ring 103 and the nozzle blade 113. In these cases, the effect of an increase in the flow rate of the leakage flow of the exhaust gas, caused by the provision of the groove 121 in the nozzle ring 103, on a reduction in the efficiency of the turbine T is less than the effect of an increase in the flow rate of the leakage flow of the exhaust gas, caused by the provision of the groove 121 in the cover ring 101, on a reduction in the efficiency of the turbine T. Therefore, if the groove 112 is formed in at least the nozzle ring 103, a reduction in the efficiency of the turbine T can be suppressed more effectively.

[0076] Specifically, in turbine T, from the axial direction of the turbine impeller 17, the groove 121 extends along the outer edge of the nozzle vane 113 when the opening degree of the nozzle vane 113 is the specific opening degree. In this way, in specific condition S3, a portion of the groove 121 is prevented from being axially opposite the nozzle vane 113. Specifically, in specific condition S3, the groove 121 does not intersect the nozzle vane 113 from the axial direction. Therefore, an increase in the flow rate of the leakage flow, which is the flow of exhaust gas escaping through a space between the shroud ring 101 and the nozzle vane 113, can be suppressed. Thus, a reduction in the efficiency of turbine T can be more effectively suppressed.

[0077] In particular, in the turbine T, the groove 121 extends from the inner circumferential edge to the outer circumferential edge of the surface 101d of the cover ring 101. In this way, the foreign material that has been introduced into the groove 121 can be effectively removed along the groove 121. If, for example, the groove 121 does not extend from the inner circumferential edge to the outer circumferential edge of the surface 101d of the cover ring 101, a step is formed at one end section of the groove 121. In this case, the removal of the foreign material can be hindered by the step at the end section of the groove 121. In contrast, if the groove 121 extends from the inner circumferential edge to the outer circumferential edge of the surface 101d of the cover ring 101, such a step is not formed, and therefore the foreign material can be effectively removed.

[0078] Fig. Figure 6 is a side view of a cover band ring 101A in a modification example, viewed from the side of the bearing housing 3. The modification example is an example in which the cover band ring 101 described above is replaced with the cover band ring 101A in the turbine T. In the modification example, the path of a groove 121A formed in the cover band ring 101A differs from the path of the groove 121 in the example of Fig. 5, as described above.

[0079] As in Fig. As shown in Figure 6, a plurality of grooves 121A, extending in a direction inclined with respect to the circumferential direction of the turbine impeller 17, are formed at equal intervals in the circumferential direction in the surface 101d of the cover band ring 101A, in the same manner as in the example of Fig. 5, as described above. Each groove 121A is designed to run close to each nozzle vane 113. However, the number of grooves 121A is not limited to that of this example.

[0080] In the example of Fig. 6 the groove 121A extends from the inner circumferential edge to the outer circumferential edge of the surface 101d of the cover band ring 101A, in the same way as in the example of Fig. 5, as described above. However, it is not required that the groove 121A extends from the inner circumferential edge to the outer circumferential edge of the surface 101d of the cover band ring 101A.

[0081] In the example of Fig. 6 cuts, unlike the example of Fig. 5, as described above, the groove 121A intersects the nozzle vane 113 regardless of the opening degree of the nozzle vane 113, as viewed in the axial direction of the turbine impeller 17. In each of the fully closed state S1, the fully open state S2, or a state in which the opening degree of the nozzle vane 113 is an opening degree between the minimum and maximum values, the groove 121A intersects the nozzle vane 113, as viewed in the axial direction of the turbine impeller 17. That is to say, as viewed in the axial direction of the turbine impeller 17, the groove 121A intersects the nozzle vane 113 regardless of the opening degree of the nozzle vane 113.

[0082] In the example of Fig. 6. The groove 121A is located in a counterclockwise direction with respect to point P1, which marks the pivot axis of the nozzle vane 113 that intersects the groove 121A, as viewed in the axial direction of the turbine impeller 17. That is, the groove 121A lies, in the axial direction, opposite a radially inner part with respect to point P1 of the nozzle vane 113 that intersects the groove 121A, as viewed in the axial direction of the turbine impeller 17. However, the groove 121A can also be located in a clockwise direction with respect to point P1, which marks the pivot axis of the nozzle vane 113 that intersects the groove 121A, as viewed in the axial direction of the turbine impeller 17. That is, the groove 121A can lie, in the axial direction, opposite a radially outer part with respect to point P1 of the nozzle vane 113. 113 opposite, which intersects the groove 121A, from the perspective in the axial direction of the turbine impeller 17.

[0083] In the example of Fig. 6. The entire groove 121A has a straight shape. However, part of the groove 121A may have a curved shape, or the entire groove 121A may have a curved shape. Part of the groove 121A may be bent or curved.

[0084] As described above, in the modification example, in the same way as in the example of Fig. 5, as described above, at least one groove 121A extending in a direction inclined with respect to the circumferential direction of the turbine impeller 17 is formed in the surface 101d, which faces the plurality of nozzle vanes 113 in the cover band ring 101A, which is the first annular component. In this way, a foreign substance supplied to the variable capacity mechanism 100 can be guided to the groove 121A, and therefore the penetration of the foreign substance into a space between the surface 101d of the cover band ring 101A and the nozzle vane 113 can be suppressed. Furthermore, the variable capacity mechanism 100 can cause the nozzle vane 113 to scrape out and remove the foreign substance that has been guided to the groove 121A by opening and closing the nozzle vane 113. In this way, the penetration of the foreign substance into the space between the surface 101d of the cover band ring 101A and the nozzle vane 113 can be suppressed more effectively.

[0085] In the example of Fig. From the perspective of the axial direction of the turbine impeller 17, the groove 121A cuts into the nozzle vane 113, regardless of the opening degree of the nozzle vane 113. During operation of the turbocharger TC, the variable capacity mechanism 100 determines a target opening degree of the nozzle vane 113 based on various pieces of information and controls the opening degree of the nozzle vane 113 to achieve this target opening degree. In this way, the foreign material that has been introduced into the groove 121A can be scraped out and removed by the nozzle vane 113. Thus, the variable capacity mechanism 100 performs a removal process in which the nozzle vane 113 scrapes out and removes the foreign material that has been introduced into the groove 121A by changing the opening degree of the nozzle vane 113.

[0086] The foregoing describes an example in which the groove 121A is formed in the cover band ring 101A, which is the first annular component.

[0087] However, in the same way as in the example of Fig. 5, as described above, the groove 121A shall be formed in the surface 103d, which is opposite the plurality of nozzle vanes 113 in the nozzle ring 103, which is the second annular component.

[0088] In this modification example, from the perspective of the axial direction of the turbine impeller 17, the groove 121A intersects the nozzle vane 113 regardless of the opening degree of the nozzle vane 113. In this way, a portion of the groove 121A is axially opposite the nozzle vane 113, irrespective of the opening degree of the nozzle vane 113. Therefore, during operation of the turbocharger TC, if the opening degree of the nozzle vane 113 changes, the foreign material that has been directed to the groove 121A can be scraped out and removed by the nozzle vane 113. In this way, the foreign material can be effectively removed during operation of the turbocharger TC.

[0089] Although the embodiment of the present disclosure has been described above with reference to the attached drawings, it is not necessary to state that the present disclosure is not limited to the embodiment described above. It is obvious that a person skilled in the art may arrive at various modifications or alterations within the scope of the claims, and it is naturally understood that these examples also fall within the technical scope of the present disclosure.

[0090] The foregoing example describes how turbine T is mounted on turbocharger TC. However, a device on which turbine T is mounted can be a device other than turbocharger TC. Reference symbol list 17 Turbine wheel 101 Cover band ring (first ring-shaped component) 101A Cover band ring (first ring-shaped component) 101d area 103 Nozzle ring (second ring-shaped component) 103d area 107 Drive ring (third ring-shaped component) 113 nozzle blades 121 Nut 121A Nut T Turbine TC turbocharger QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] JP 2023-145938

[0001] JP 2004-116313 A

[0003]

Claims

[1] Turbine with: a turbine impeller; a plurality of nozzle vanes, which are placed on a radially outer side with respect to the turbine impeller, in order to be spaced apart from each other in a circumferential direction of the turbine impeller, and which are each provided to be pivotable about a pivot axis extending along an axial direction of the turbine impeller; a first ring-shaped component and a second ring-shaped component extending in the circumferential direction and sandwiching the multitude of nozzle vanes from both sides in the axial direction; and at least one groove which is formed in a surface opposite the plurality of nozzle vanes in at least one of the first annular component or the second annular component and extends in a direction which is inclined with respect to the circumferential direction. [2] Turbine according to claim 1, wherein, from an axial view, the at least one groove extends along an outer edge of a corresponding plurality of nozzle vanes, where an opening degree of the corresponding plurality of nozzle vanes is a specific opening degree. [3] Turbine according to claim 1, wherein, from the axial view, the at least one groove intersects a corresponding plurality of nozzle vanes, irrespective of the degree of opening of the corresponding plurality of nozzle vanes. [4] Turbine according to claim 1, wherein the at least one groove extends from an inner circumferential edge to an outer circumferential edge of the surface. [5] Turbine according to claim 1, further comprising a third annular component which is provided on one side opposite to the plurality of nozzle vanes with reference to the second annular component, extends in the circumferential direction and is provided to be pivotable in connection with the plurality of nozzle vanes, wherein the at least one groove is formed in at least the first annular component. [6] Turbine according to claim 1, further comprising a third annular component which is formed on one side opposite to the plurality of nozzle vanes with reference to the second annular component, extends in the circumferential direction and is provided to be pivotable in connection with the plurality of nozzle vanes, wherein the at least one groove is formed in at least the second annular component. [7] Turbocharger with the turbine according to any one of claims 1 to 6.

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