JP6200350B2 - Radial turbine or mixed flow turbine - Google Patents

Description

  The present disclosure relates to radial turbines or mixed flow turbines.

  In the fields of turbochargers mounted on automobile engines, expansion turbines used in power generation engines, and small gas turbines, the turbine rotation speed and turbine output can be made variable, or high response to engine output changes. In order to demonstrate the performance, a radial turbine and a mixed flow turbine having a variable mechanism capable of adjusting the flow rate of exhaust gas introduced into the turbine are known.

  For example, Patent Document 1 discloses a variable capacity turbocharger in which a variable mechanism including a variable nozzle is provided in a nozzle portion of a turbine housing. The variable nozzle includes a plurality of nozzle blades arranged in the circumferential direction in the nozzle portion of the turbine housing, and an actuator that rotates the plurality of nozzle blades.

  Further, in Patent Document 2, a so-called twin scroll turbocharger having two scroll passages through which exhaust gas flows includes a flow rate adjusting mechanism for adjusting the flow rate of exhaust gas flowing through the two scroll passages as the variable mechanism. A turbocharger is disclosed. In this type of twin-scroll turbocharger, exhaust gas corresponding to the design flow rate flows through both scroll channels at the maximum flow rate, exhaust gas flows only from one scroll channel at the minimum flow rate, and the other scroll channel flows into the other scroll channel. Do not flow exhaust gas. At the intermediate flow rate, exhaust gas corresponding to the design flow rate is caused to flow through one scroll flow path, and the flow rate of the exhaust gas flowing through the other scroll flow path is adjusted.

  Further, in Patent Document 3, in a turbocharger having a configuration in which exhaust gas can be introduced from a nozzle hole provided in the shroud portion in addition to the nozzle portion, a nozzle hole provided in the shroud portion as the variable mechanism. There is disclosed a supercharger provided with a flow rate adjusting mechanism for adjusting the flow rate of exhaust gas flowing through the engine.

JP 2000-154728 A JP 2009-281197 A JP 2007-23893 A

  However, in the variable capacity turbocharger disclosed in Patent Document 1 described above, it is necessary to ensure a large gap between the nozzle blade and the inner wall surface of the housing in order to cope with thermal deformation due to the influence of high-temperature exhaust gas. . Therefore, there is a problem that the turbine efficiency decreases due to the exhaust gas leaking from the gap. In addition, since a movable member called a variable nozzle is used for a nozzle portion through which high-temperature exhaust gas flows, there is a problem that there is a higher risk of troubles such as breakage than when a fixed member is used.

  Further, in the turbocharger disclosed in Patent Document 2 described above, the nozzle outlets of the two scroll passages are adjacent to each other in the turbine axial direction, so that one nozzle having a high pressure at the minimum flow rate or intermediate flow rate. There is a problem that a reverse flow phenomenon occurs in which the exhaust gas flows from the outlet to the other nozzle outlet having a low pressure, thereby causing a pressure loss and lowering the turbine efficiency.

  Further, in the turbocharger disclosed in Patent Document 3 described above, particularly when exhaust gas does not flow from the nozzle hole provided in the shroud portion, pressure loss is generated by this nozzle hole, resulting in a decrease in turbine efficiency. Then there is a problem.

  At least one embodiment of the present invention has been made in view of the conventional problems as described above, and the object thereof is low risk of occurrence of trouble such as breakage and high turbine efficiency in a wide flow range. It is an object to provide a radial turbine or a mixed flow turbine that exhibits the following.

A radial turbine or mixed flow turbine according to at least one embodiment of the present invention includes:
(1)
A casing including a turbine housing in which a spiral or annular scroll space through which exhaust gas flows is formed;
A rotating shaft that is rotatably accommodated in the casing, a hub that is fixed to the rotating shaft and configured to continuously decrease in radius toward the distal end side, and radially from the peripheral surface of the hub A plurality of blades provided in a protruding manner, and a turbine blade comprising:
A dividing wall that forms two scroll channels, a shroud-side scroll channel and a hub-side scroll channel, by dividing the scroll space formed around the turbine rotor blade inlet of the turbine blade in the turbine axial direction. And comprising
Between the shroud side scroll passage and the turbine blade inlet, a nozzle inlet facing the shroud side scroll passage is provided, and the exhaust gas flowing through the shroud side scroll passage is guided to the turbine blade inlet. A plurality of shroud side nozzle flow paths are formed in the circumferential direction,
Between the hub side scroll flow path and the turbine blade inlet, a nozzle inlet facing the hub side scroll flow path is provided, and the exhaust gas flowing through the hub side scroll flow path is guided to the turbine blade inlet. A plurality of hub side nozzle flow paths for the circumferential direction are formed,
Each of the nozzle outlets of the plurality of shroud-side nozzle passages and the nozzle outlets of the plurality of hub-side nozzle passages is radially opposed to the turbine rotor blade inlet, and has the same axis in the turbine axial direction. An annular nozzle outlet is configured by being alternately arranged in the circumferential direction at the direction position.

  According to the radial turbine or the mixed flow turbine described in (1) above, each of the nozzle outlets of the plurality of shroud side nozzle channels and the nozzle outlets of the plurality of hub side nozzle channels is connected to the turbine blade inlet. The annular nozzle outlets are configured by opposing each other in the radial direction and alternately adjacent in the circumferential direction at the same axial position in the turbine axial direction. For this reason, compared with what the nozzle exit of two scroll flow paths as disclosed by patent document 2 adjoins in the turbine axial direction, the other nozzle exit where pressure is low from one nozzle outlet where pressure is high The backflow phenomenon in which the exhaust gas flows to the outside is suppressed. Thereby, the fall of the turbine efficiency accompanying generation | occurrence | production of a pressure loss can be prevented.

  Further, according to the radial turbine or the mixed flow turbine described in the above (1), unlike the variable capacity turbine provided with the variable nozzle as disclosed in Patent Document 1, no movable member is provided in the nozzle portion. For this reason, the problem of the turbine efficiency fall by the leakage flow from the clearance gap between a movable member and a wall surface does not arise. In addition, since no movable member is provided in the nozzle portion through which high-speed and high-temperature exhaust gas flows, the risk of breakage and the like is low, and structural reliability is high.

  (2) In some embodiments, in the radial turbine or the mixed flow turbine of (1), the flow rate of the exhaust gas flowing through at least one of the shroud-side scroll flow path and the hub-side scroll flow path can be adjusted. A flow rate adjusting mechanism is further provided.

  According to the radial turbine or the mixed flow turbine described in (2) above, the flow rate of the exhaust gas flowing through at least one of the shroud-side scroll passage and the hub-side scroll passage can be adjusted by the flow rate adjusting mechanism. For example, the flow rate adjustment mechanism can control the exhaust gas corresponding to the design flow rate to flow in both scroll passages at the maximum flow rate. Further, it is possible to control the exhaust gas to flow only from one scroll flow path at the minimum flow rate. Further, at the intermediate flow rate, it is possible to control the exhaust gas corresponding to the design flow rate to flow through one scroll flow path and adjust the flow rate of the exhaust gas flowing through the other scroll flow path. Therefore, by providing such a flow rate adjusting mechanism, a variable mechanism capable of realizing high turbine efficiency in a wide flow range from the minimum flow rate to the maximum flow rate can be configured.

  (3) In some embodiments, in the radial turbine or the mixed flow turbine according to the above (1) and (2), the shroud side nozzle flow path is in a direction orthogonal to the turbine axial direction in meridional view. Along the turbine blade inlet (4a). The hub side nozzle flow path is formed so as to extend incline with respect to the turbine axial direction so as to extend along the direction from the turbine rotor blade inlet toward the turbine rotor blade outlet in the meridian view.

  According to the radial turbine or mixed flow turbine of (3) above, the flow of the exhaust gas flowing out from the shroud-side nozzle flow path is changed to a radial flow substantially perpendicular to the turbine axial direction, as in the conventional radial turbine. I can do it. Therefore, the turning angle of the exhaust gas flow is made smaller than in the case where the flow of the exhaust gas flowing through the shroud side nozzle flow path flows along the direction inclined with respect to the turbine shaft so as to go from the shroud side to the hub side. I can do it. Thereby, a pressure loss can be suppressed and the fall of turbine efficiency can be prevented. In addition, the flow angle of the exhaust gas flowing out from the hub side nozzle flow path can be made smaller than the conventional radial turbine, so the pressure loss is further suppressed and the turbine efficiency is prevented from being lowered. I can do it.

(4) In some embodiments, in the radial turbine or the mixed flow turbine according to (3), the partition wall extends in a direction orthogonal to the turbine axial direction and divides the scroll space. And a hub-side contact portion that extends from the inner peripheral portion of the divided portion toward the hub side and contacts the hub side wall surface of the casing. The hub side wall surface of the casing as viewed from the meridian plane is in the direction of the turbine axis so that the radial distance between the hub side wall surface and the rotating shaft decreases from the nozzle inlet to the nozzle outlet of the hub side nozzle channel. And inclined to extend. The hub side nozzle flow path includes at least a hub side space defined by a groove formed on the hub side contact surface of the hub side contact portion and a hub side wall surface.
The radial turbine or the mixed flow turbine further includes a plurality of shroud side nozzle blades formed at intervals in the circumferential direction between the inner peripheral portion of the divided portion and the shroud side wall surface of the casing. The shroud-side nozzle flow path is configured to include a shroud-side space defined by the inner peripheral portion of the divided portion, two shroud-side nozzle blades adjacent in the circumferential direction, and the shroud side wall surface of the casing. .

  According to the radial turbine or mixed flow turbine of (4) above, the hub side nozzle flow path is a hub side space defined by a groove formed on the hub side contact surface of the hub side contact portion and the hub side wall surface. At least. For this reason, the hub side nozzle flow path can be formed by a groove portion that can be easily processed without forming a through hole in the dividing wall. When a through-hole is formed in the dividing wall, it is necessary to manufacture by complicated casting or the like, but if it is a groove having an opening on the contact surface, it can be manufactured by casting with a relatively simple core. . Even when high surface processing accuracy is required, it can be easily processed by an end mill.

  Further, according to the radial turbine or the mixed flow turbine of (4), the plurality of shroud side nozzle blades formed at intervals in the circumferential direction between the inner peripheral portion of the divided portion and the shroud side wall surface of the casing. Further prepare. The shroud-side nozzle flow path is configured to include a shroud-side space defined by the inner peripheral portion of the divided portion, two shroud-side nozzle blades adjacent in the circumferential direction, and the shroud side wall surface of the casing. . For this reason, the flow of exhaust gas flowing out from the shroud-side scroll flow path can be guided in the circumferential direction by the pressure surface and the suction surface of the two shroud-side nozzle blades adjacent in the circumferential direction, and the turbine efficiency can be further improved. It can be further enhanced.

  (5) In some embodiments, in the radial turbine or the mixed flow turbine according to (4), the shroud side nozzle blade has an opening in a cross section on the hub side connected to the divided portion and a rear end portion. A groove-shaped or through-hole-shaped hollow portion is formed. The hub-side nozzle flow path is configured by a hub-side space and a hollow portion communicating with the hub-side space in a cross section on the hub side.

  According to the radial turbine or mixed flow turbine of (5) above, the hub side nozzle flow path is constituted by the hub side space and the groove-shaped or through-hole-shaped hollow portion formed inside the shroud-side nozzle blade. The For this reason, the exhaust gas flowing through the shroud-side nozzle flow path including the shroud-side space formed by two shroud-side nozzle blades adjacent in the circumferential direction, and the groove shape or the through-hole shape formed inside the shroud-side nozzle blade The exhaust gas flowing through the hub-side nozzle flow path including the hollow portion flows without interfering with each other to the respective nozzle outlets. Thereby, the pressure loss of exhaust gas can be suppressed and turbine efficiency can be improved further.

  (6) In some embodiments, in the radial turbine or mixed flow turbine of (4) and (5) above, the circumferential width of the nozzle outlet of the hub side nozzle flow path is the nozzle outlet of the shroud side nozzle flow path. It is formed to be smaller than the circumferential width.

  According to the radial turbine or the mixed flow turbine of (6) above, for example, the exhaust gas corresponding to the design flow rate flows from both nozzle flow paths at the maximum flow rate, and the hub side nozzle flow having a small circumferential width at the nozzle outlet at the minimum flow rate. The exhaust gas is allowed to flow only from the passage, and at the intermediate flow rate, the exhaust gas corresponding to the design flow rate is caused to flow through the hub side nozzle flow path, and the flow rate of the exhaust gas flowing through the shroud side nozzle flow path having a large circumferential width at the nozzle outlet is adjusted. Thus, it is possible to configure a variable mechanism that realizes high turbine efficiency in a wide flow range from the minimum flow rate to the maximum flow rate.

  (7) In some embodiments, in the radial turbine or the mixed flow turbine according to the above (4) to (6), the nozzle inlet of the hub side nozzle flow path is the meridional view of the nozzle inlet (34A). When the maximum width of the opening is represented by WA and the maximum width of the opening along the circumferential direction is represented by WC, WA <WC.

  According to the radial turbine or mixed flow turbine of (7) above, the length of the casing in the turbine axial direction is shortened by making the nozzle inlet of the hub-side nozzle passage longer in the circumferential direction than in the meridian plane direction. I can do it. Thereby, the shape of a casing can be made compact.

  (8) In some embodiments, in the radial turbine or the mixed flow turbine according to (5), the shroud-side nozzle blade includes a pressure surface oriented on the outer circumferential side in a cross-sectional view perpendicular to the turbine axis, and It has a wing-shaped outer surface shape having two peripheral surfaces of a suction surface oriented on the inner peripheral side. Then, in a cross-sectional view perpendicular to the turbine axis, it intersects with the suction surface rear end of the adjacent shroud nozzle blade and is orthogonal to the downstream end surface defined by the pressure surface rear end and the suction surface rear end of the nozzle outlet. The nozzle outlet of the hub side nozzle flow path is configured such that the imaginary line extending in the direction to pass passes between the pressure surface rear end and the suction surface rear end.

According to the radial turbine or mixed flow turbine of (8) above, for example, even when exhaust gas flows only from the hub side nozzle flow path at the minimum flow rate, the exhaust gas flowing out from the hub side nozzle flow path is The flow of the exhaust gas flows through the annular flow path along the circumferential direction without being largely hindered by the negative pressure surface of the adjacent shroud side nozzle blade. For this reason, the exhaust gas flowing out from the hub side nozzle flow path flows without interruption in the circumferential direction, and flows into the turbine rotor blade inlet from the entire annular flow path.
At the maximum flow rate, the exhaust gas flows out from the area where the nozzle outlets of both the hub side nozzle flow path and the shroud side nozzle flow path are combined. Here, it is preferable that the throat widths of the nozzle outlets of the two nozzle channels are designed so that the flow rates of the exhaust gas flowing out from the hub side nozzle channel and the shroud side nozzle channel are equal at the maximum flow rate. . The exhaust gas outflow direction differs between the hub side nozzle flow path and the shroud side nozzle flow path. However, the exhaust gas flowing out from the shroud-side nozzle passage is restricted in the outflow direction by the negative pressure surface of the adjacent shroud-side nozzle blade, and flows along the negative pressure surface. Therefore, the exhaust gas flowing out from the two nozzle flow paths merges as one large exhaust gas flow without greatly disturbing the flow, and flows into the moving blade from the entire annular flow path at the moving blade inlet.
At the intermediate flow rate, the flow rate of the exhaust gas flowing out from the nozzle outlet of the shroud side nozzle flow path is slower than at the maximum flow rate described above. However, the flow width of the shroud-side nozzle flow path is narrowed by the flow of exhaust gas flowing out from the hub-side nozzle flow path, thereby accelerating the flow velocity of the exhaust gas flowing out from the shroud-side nozzle flow path. The exhaust gas flowing out from the two nozzle flow paths merges as one large exhaust gas flow without greatly disturbing the flow, and moves while having an intermediate flow angle between the minimum flow rate and the maximum flow rate. It flows into the turbine rotor blade inlet from the entire annular flow path at the blade inlet.

  As described above, in the radial turbine or the mixed flow turbine of the above (8), the exhaust gas flows from the entire annular flow path of the moving blade inlet toward the turbine moving blade inlet in a wide flow rate range from the minimum flow rate to the maximum flow rate. I can do it. Moreover, since the flow angle also changes continuously according to the change in flow rate, the control performance is the same as when the flow direction of the exhaust gas is controlled by the variable nozzle. For this reason, according to the radial turbine or the mixed flow turbine of the present embodiment, a variable mechanism that realizes high turbine efficiency can be configured in a wide flow rate range from the minimum flow rate to the maximum flow rate.

  (9) In some embodiments, in the radial turbine or the mixed flow turbine according to (5), the shroud-side nozzle blade includes a pressure surface oriented on the outer circumferential side in a cross-sectional view perpendicular to the turbine axis, and It has a wing-shaped outer surface shape having two peripheral surfaces of a suction surface oriented on the inner peripheral side. And in a cross-sectional view perpendicular to the turbine axis, it intersects the suction surface rear end of the adjacent shroud nozzle blade, and the pressure surface rear end of the nozzle outlet and the nozzle inner surface on the suction surface rear end side of the hollow portion The nozzle outlet of the hub side nozzle flow path is configured so that a virtual line extending in a direction orthogonal to the downstream end surface defined as a line connecting the shortest distance passes between the rear end of the pressure surface and the rear end of the negative pressure surface Is done.

  According to the radial turbine or mixed flow turbine of (9) above, the flow velocity component in the vertical direction is given to the downstream end face of the nozzle outlet with respect to the flow of the exhaust gas flowing out from the nozzle outlet of the hub side nozzle flow path. I can do it. Therefore, for example, at the intermediate flow rate at which the exhaust gas flows out from the nozzle outlets of both the hub side nozzle flow path and the shroud side nozzle flow path, two nozzles are used rather than the radial turbine or the mixed flow turbine of (8) described above. Mixing of the exhaust gas flowing out from the outlet is promoted. Thereby, the uniformity of a flow improves and the pressure loss at the time of flowing into a moving blade can be reduced.

  (10) In some embodiments, in the radial turbine or the mixed flow turbine according to (4) to (9), the blades are positioned on the upstream side and the downstream side in the meridional view. A rear edge, an outer edge located radially outward, and an inner edge located radially inward and secured to the peripheral surface of the hub. When the radial distance of the first intersection of the inner edge and the leading edge is represented by RH, and the radial distance of the second intersection of the outer edge and the leading edge is represented by RS, RH <RS, and the shape line of the leading edge is A convex shape is formed toward the upstream side. And the shape line of the rear-end part of a shroud side nozzle blade is formed in concave shape facing a front edge in meridional view.

  The main component of the velocity component of the exhaust gas flowing out from the hub-side nozzle flow channel is the circumferential component, but in the meridional view, it also has a radial component and an axial component, and flows in an inclined manner with respect to the turbine shaft. Flow into the turbine rotor blade inlet. However, in a radial turbine in which the leading edge of the blade has a certain radial distance, the turning angle of the exhaust gas flow in the meridional plane increases, causing separation of the exhaust gas flow on the peripheral surface of the hub, and pressure loss. Will occur.

  According to the radial turbine or mixed flow turbine of (10) above, the leading edge of the blade on the hub side is formed so as to be inclined so that the radial distance becomes shorter toward the hub side. In addition, the shape line of the rear end portion of the shroud-side nozzle blade where the nozzle outlet of the hub-side nozzle passage opens is formed in a concave shape facing the front edge in the meridian view. For this reason, the turning angle of the flow of the exhaust gas flowing out from the hub side nozzle passage in the meridional view can be reduced, and the pressure loss due to the flow angle change can be reduced.

  (11) In some embodiments, in the radial turbine or the mixed flow turbine according to (10), the nozzle outlet of the hub-side nozzle passage has a throat width of the nozzle outlet closer to the hub than the shroud. Is formed to be wide.

  In a turbine in which the flow rate of exhaust gas to be introduced fluctuates, high turbine efficiency is required in a region where the theoretical speed ratio (U / C0) is low when the flow rate is small, and in a region where the theoretical speed ratio (U / C0) is high when the flow rate is large. High turbine efficiency is required. Here, U: peripheral speed at the moving blade inlet, C0: theoretical speed.

  According to the radial turbine or mixed flow turbine of (11) above, the shape line of the leading edge of the blade is formed convex toward the upstream side. Further, the shape line of the rear end portion of the shroud side nozzle blade is formed in a concave shape facing the front edge in the meridian view. Therefore, the leading edge of the blade has a large function of the hub-side impulse turbine inclined with respect to the turbine shaft, and a function of the shroud-side reaction turbine that is substantially parallel to the turbine shaft and substantially constant in radius. Will have a large part. Therefore, by forming the throat width at the nozzle outlet of the hub side nozzle flow path wider than the throat width at the shroud side, the area where the theoretical speed ratio (U / C0) is low at a small flow rate. A lot of exhaust gas can be made to flow at a small flow angle to the hub side of the leading edge where the function of the impulse turbine that exhibits high turbine efficiency is large. Further, a large flow angle allows a large flow angle of exhaust gas to flow into the shroud side of the leading edge 4a, which has a large function of a reaction turbine that exhibits high turbine efficiency in a region where the theoretical speed ratio (U / C0) is high at a large flow rate. I can do it. As a result, the turbine efficiency can be improved in a wide flow range from a small flow rate to a large flow rate.

  (12) In some embodiments, in the radial turbine or the mixed flow turbine according to (4) to (9), the blades have a leading edge located on the upstream side, a trailing edge located on the downstream side, and a radius. An outer edge located on the outer side in the direction and an inner edge located on the inner side in the radial direction and fixed to the peripheral surface of the hub. The leading edge has a shape line consisting of a certain radial distance. The hub is formed so that the tangential direction at the outer peripheral edge of the peripheral surface of the hub is inclined by 5 to 30 ° on the back side of the hub of the turbine rotor blade with respect to the direction orthogonal to the turbine axis in the meridian view. The The hub side wall surface of the casing is in the turbine axial direction so that the radial distance between the hub side wall surface and the rotation shaft becomes shorter from the nozzle inlet to the nozzle outlet of the hub-side nozzle channel in the meridian view. Inclined and extended.

  The main component of the velocity component of the exhaust gas flowing out from the hub-side nozzle flow channel is the circumferential component, but in the meridional view, it also has a radial component and an axial component, and flows with an inclination to the turbine shaft. Flow into the wing. However, in the radial turbine in which the tangential direction at the outer peripheral edge of the peripheral surface of the hub extends in the radial direction, the turning angle of the exhaust gas flow in the meridian view is increased, and the exhaust gas flow is separated from the hub peripheral surface. And pressure loss occurs.

  According to the radial turbine or mixed flow turbine of (12) above, the hub has a tangential direction at the outer peripheral edge of the peripheral surface of the hub with respect to the direction perpendicular to the turbine axis. Are inclined at 5 to 30 °. For this reason, the turning angle of the flow of the exhaust gas flowing out from the hub side nozzle passage in the meridional view can be reduced, and the pressure loss due to the flow angle change can be reduced.

  (13) In some embodiments, in the radial turbine or the mixed flow turbine according to the above (4) to (12), the nozzle outlet of the shroud side nozzle passage is larger than the nozzle outlet of the hub side nozzle passage. It has a road area. The flow rate adjusting mechanism includes a shroud side scroll channel or a flow rate adjustment valve capable of adjusting the channel area of the shroud side exhaust pipe that introduces exhaust gas into the shroud side scroll channel.

According to the radial turbine or mixed flow turbine of (13) above, it is not the flow path area of the hub side scroll flow path or the flow area of the hub side exhaust pipe that introduces exhaust gas into the hub side scroll flow path, but the shroud side. The flow path area of the scroll flow path or the flow path area of the shroud side exhaust pipe that introduces exhaust gas into the shroud side scroll flow path is adjusted. For this reason, since only one flow rate adjusting valve is required as compared with the case where the flow channel areas of both scroll flow channels are adjusted, the structure and control of the flow rate adjusting mechanism can be simplified.
In addition, the nozzle outlet of the shroud side nozzle flow path has a larger flow area than the nozzles of the hub side nozzle flow path, and the shroud side nozzle flow path has more exhaust gas than the hub side nozzle flow path. Can be shed. And the flow volume adjustment mechanism of this embodiment is comprised so that the flow volume of the exhaust gas which flows through this shroud side nozzle flow path may be adjusted. For this reason, compared with the case where the flow volume of the exhaust gas which flows through a hub side nozzle flow path is adjusted, flow volume adjustment can be performed in a wider range.

  (14) In some embodiments, in the radial turbine or the mixed flow turbine according to (4) to (13), the dividing wall includes a dividing portion and a hub-side contact portion formed integrally with the dividing portion. It consists of. This dividing wall is formed of a member separate from the turbine housing. The shroud side nozzle blade is constituted by a separate member from the dividing wall and the turbine housing. The turbine housing is composed of a hub side housing part located on the hub side in the meridian view and a shroud side housing part located on the shroud side in the meridional view, which is a separate member from the hub side housing part.

  According to the radial turbine or mixed flow turbine of (14) above, the dividing wall, the shroud side nozzle blades, and the turbine housing are each composed of separate members. Further, the turbine housing includes a hub side housing part and a shroud side housing part which are formed of separate members. For this reason, the radial turbine or mixed flow turbine of this embodiment can be manufactured by assembling and integrating these members in the turbine axial direction, which is excellent in manufacturability.

  (15) In some embodiments, in the radial turbine or the mixed flow turbine according to (14), the dividing wall and the shroud side housing portion are formed symmetrically with respect to the turbine axis.

  According to the radial turbine or mixed flow turbine of (15) above, the dividing wall and the shroud side housing portion are formed symmetrically with respect to the turbine axis. For this reason, when the dividing wall and the shroud side housing part are assembled and integrated in the turbine axial direction, the step of positioning the circumferential direction position can be omitted, and the assemblability is excellent.

  (16) In some embodiments, in the radial turbine or mixed flow turbine according to (14) and (15) above, the hub side wall surface of the casing is formed of a member separate from the turbine housing. It consists of the wall surface of the back plate for preventing the exhaust gas from leaking along the back surface.

  According to the radial turbine or the mixed flow turbine of (16) above, the hub side wall surface of the casing described above is composed of the wall surface of the back plate made of a member different from the turbine housing. For this reason, the radial turbine or mixed flow turbine of this embodiment can be manufactured by assembling and integrating the back plate with the turbine housing and the like in the turbine axial direction.

  (17) In some embodiments, in the radial turbine or the mixed flow turbine according to the above (14) and (15), the casing is an elastic member supported by a hub-side housing portion that is formed of a member different from the turbine housing. A deformable first plate member is included. The first plate member is inclined with respect to the turbine axial direction so that the radial distance between the hub side wall surface and the rotating shaft is shortened from the nozzle inlet of the hub side nozzle flow path toward the nozzle outlet in the meridian plane view. There is an inclined surface, and this inclined surface constitutes the hub side wall surface of the casing. And the hub side contact part of a division wall is comprised so that it may contact | abut with the inclined surface of this 1st plate member.

  According to the radial turbine or mixed flow turbine of (17) above, the hub-side contact portion of the dividing wall contacts the inclined surface of the first plate member that can be elastically deformed. For this reason, when the dividing wall comprised of a member different from the turbine housing is thermally deformed by the high-temperature exhaust gas, the first plate member is elastically deformed to absorb the heat deformation. Therefore, even if the dividing wall and the shroud side nozzle blades are configured by a member different from the turbine housing, a gap or the like does not occur in the hub side nozzle flow path due to thermal deformation.

  (18) In some embodiments, in the radial turbine or the mixed flow turbine according to (17), the casing further includes an elastically deformable second plate member fixed to the shroud side housing portion. The second plate member has a side surface constituting at least a part of a shroud side wall surface extending along a direction orthogonal to the turbine axis in meridional view. The shroud side nozzle blade is configured to abut against the side surface of the second plate member and be supported by the side surface and the dividing wall.

  According to the radial turbine or the mixed flow turbine of the above (18), the shroud side nozzle blade is supported between the second plate member and the dividing wall in a state of being in contact with the elastically deformable second plate member. For this reason, when the partition wall and shroud side nozzle blades, which are configured separately from the turbine housing, are thermally deformed by high-temperature exhaust gas, the second plate member is elastically deformed to absorb the heat deformation. I can do it. Therefore, even if the dividing wall and the shroud side nozzle blades are configured by a member different from the turbine housing, a gap or the like does not occur in the hub side nozzle flow path due to thermal deformation.

  (19) In some embodiments, in the radial turbine or the mixed flow turbine according to the above (1) to (3), a plurality of casing shrouds formed at intervals in the circumferential direction on the inner peripheral portion of the dividing wall A plurality of shroud-side nozzle portions that come into contact with the side wall surface, and a plurality of hub-side nozzle portions that are formed in the inner peripheral portion of the dividing wall at intervals in the circumferential direction and that come into contact with the hub side wall surface of the casing. . The shroud-side nozzle portion is a hub-side groove having an inlet facing the hub-side scroll flow path and an outlet facing the turbine rotor blade inlet, which communicates from the radially outer end to the inner end on the hub side inside the shroud-side nozzle portion. Part. The hub side nozzle portion has a shroud side groove having an inlet facing the shroud side scroll flow path and an outlet facing the turbine rotor blade inlet inside the hub side nozzle portion, leading from the radially outer end to the inner end on the shroud side. Part. The shroud side nozzle flow path is formed by a shroud side wall surface of the casing and two side wall surfaces and a bottom wall surface facing each other in the circumferential direction in the shroud side groove portion of the hub side nozzle portion. The hub side nozzle flow path is formed by a hub side wall surface of the casing and two side wall surfaces and a bottom wall surface facing each other in the circumferential direction in the hub side groove portion of the shroud side nozzle portion. The nozzle outlet of the shroud side nozzle flow path is the outlet of the shroud side groove, and the nozzle outlet of the hub side nozzle flow path is the outlet of the hub side groove. Each of the outlets of the plurality of shroud side grooves and the outlets of the plurality of hub side grooves is opposed to the turbine blade inlet in the radial direction, and alternately in the circumferential direction at the same axial position in the turbine axial direction. An annular nozzle outlet is configured by being arranged adjacent to each other.

  (20) In some embodiments, in the radial turbine or the mixed flow turbine according to (1) to (3), the dividing wall extends in a direction orthogonal to the turbine axial direction and divides the scroll space. It consists of a plate-shaped divided portion and a hub-side abutting portion that extends from the inner peripheral portion of the divided portion toward the hub side and abuts against the hub side wall surface of the casing. The radial turbine or the mixed flow turbine further includes a plurality of shroud side nozzle blades formed at intervals in the circumferential direction between the inner peripheral portion of the divided portion and the shroud side wall surface of the casing. The shroud side nozzle blade has a leading edge shape that extends from the inner peripheral portion of the divided portion to the shroud side along the turbine axial direction and is formed substantially parallel to the turbine axial direction in the meridian view. In the cross-sectional view in the direction orthogonal to the turbine axis, the outer surface has a blade shape having two peripheral surfaces, a pressure surface oriented on the outer peripheral side and a negative pressure surface oriented on the inner peripheral side. The nozzle inlet of the hub side nozzle flow path is formed on the outer peripheral end surface located on the outer peripheral side of the hub side contact portion when the hub side contact portion is viewed from the turbine axial direction. The outer peripheral end surface extends substantially in parallel with the nozzle outlet in the meridian view, or the radial distance between the hub side wall surface and the rotation shaft extends from the nozzle inlet of the hub side nozzle channel toward the nozzle outlet. It extends in a direction substantially orthogonal to the hub side wall surface of the casing extending so as to be short, or is formed so as to extend along the radial direction. The hub side nozzle flow path has a through hole formed inside the dividing wall, or a hub side space formed in a groove shape when the dividing wall is viewed from the hub side, and a shroud side nozzle communicating with the hub side space. A through hole formed inside the blade, or a hollow portion formed in a groove shape when the shroud side nozzle blade is viewed from the hub side. The nozzle outlet of the hub side nozzle flow path is formed substantially parallel to the turbine axis direction in the meridional view at the inner peripheral end of the shroud side nozzle blade when the shroud side nozzle blade is viewed from the turbine axis direction. In addition, it is formed between two rear ends formed at the rear end portion of the shroud-side nozzle blade in a cross-sectional view in a direction perpendicular to the turbine axis. The shroud-side nozzle flow path includes a shroud-side space defined by an inner peripheral portion of the divided portion, two shroud-side nozzle blades adjacent in the circumferential direction, and a shroud side wall surface of the casing. The nozzle outlet of the shroud-side nozzle flow path is an area excluding the nozzle outlet of the hub-side nozzle flow path in a circumferential area where two rear ends of the shroud-side nozzle blades are present in a cross-sectional view perpendicular to the turbine axis. Formed.

  (21) In some embodiments, in the radial turbine or the mixed flow turbine according to the above (1) to (3), the dividing wall extends in a direction perpendicular to the turbine axial direction and divides the scroll space. It consists of a plate-shaped divided portion and a hub-side abutting portion that extends from the inner peripheral portion of the divided portion toward the hub side and abuts against the hub side wall surface of the casing. The radial turbine or the mixed flow turbine further includes a plurality of shroud side nozzle blades formed at intervals in the circumferential direction between the inner peripheral portion of the divided portion and the shroud side wall surface of the casing. The shroud side nozzle blade has a leading edge shape that extends from the inner peripheral portion of the divided portion to the shroud side along the turbine axial direction and is formed substantially parallel to the turbine axial direction in the meridian view. In the cross-sectional view in the direction orthogonal to the turbine axis, the outer surface has a blade shape having two peripheral surfaces, a pressure surface oriented on the outer peripheral side and a negative pressure surface oriented on the inner peripheral side. The nozzle inlet of the hub side nozzle flow path is formed on the outer peripheral end surface located on the outer peripheral side of the hub side contact portion when the hub side contact portion is viewed from the turbine axial direction. When viewed from the top, it extends approximately parallel to the nozzle outlet, or extends from the nozzle inlet of the hub side nozzle flow path to the nozzle outlet so that the radial distance between the hub side wall surface and the rotation shaft becomes shorter. It extends in a direction substantially perpendicular to the hub side wall surface of the casing, or is formed so as to extend along the radial direction. The hub side nozzle flow path has a through hole formed inside the dividing wall, or a hub side space formed in a groove shape when the dividing wall is viewed from the hub side, and a shroud side nozzle communicating with the hub side space. A hollow portion is included when the through-hole shape formed inside the blade or the shroud-side nozzle blade is viewed from the hub side and formed into a groove shape. The nozzle outlet of the hub side nozzle flow path is a turbine rotor blade formed in a convex shape in the meridian view at the inner peripheral end of the shroud side nozzle blade when the shroud side nozzle blade is viewed from the turbine axial direction. It is formed in a concave shape having a substantially constant separation distance with respect to the leading edge of the blade, and in a cross-sectional view in a direction orthogonal to the turbine axis, between the two rear ends formed at the rear end portion of the shroud side nozzle blade Formed.

  (22) In some embodiments, in the radial turbine or the mixed flow turbine according to the above (1) to (3), the dividing wall extends in a direction perpendicular to the turbine axial direction and divides the scroll space. It consists of a plate-shaped divided portion and a hub-side abutting portion that extends from the inner peripheral portion of the divided portion toward the hub side and abuts against the hub side wall surface of the casing. The radial turbine or the mixed flow turbine further includes a plurality of shroud side nozzle blades formed at intervals in the circumferential direction between the inner peripheral portion of the divided portion and the shroud side wall surface of the casing. The shroud side nozzle blade has a leading edge shape that extends from the divided portion to the shroud side along the turbine axis direction in the meridian view and is formed substantially parallel to the turbine axis direction. In a cross-sectional view in a direction perpendicular to the outer surface, it has a wing-shaped outer surface shape having two peripheral surfaces: a pressure surface oriented on the outer peripheral side and a negative pressure surface oriented on the inner peripheral side. The nozzle inlet of the hub side nozzle flow path is formed on the outer peripheral end surface located on the outer periphery of the hub side abutting portion when the hub side abutting portion is viewed from the turbine axial direction. When viewed from the top, it extends approximately parallel to the nozzle outlet, or extends from the nozzle inlet of the hub side nozzle flow path to the nozzle outlet so that the radial distance between the hub side wall surface and the rotation shaft becomes shorter. It extends in a direction substantially perpendicular to the hub side wall surface of the casing, or is formed so as to extend along the radial direction. The hub side nozzle flow path includes a hub side space formed in the shape of a through hole formed inside the hub side contact portion or a groove shape when the hub side contact portion is viewed from the hub side. The nozzle outlet of the hub side nozzle channel opens to the side surface portion on the shroud side of the divided portion. A concave portion is formed on the pressure surface of the shroud-side nozzle blade to guide the exhaust gas flowing out from the nozzle outlet to the turbine rotor blade inlet.

  (23) In some embodiments, in the radial turbine or the mixed flow turbine of (22), a concave guide groove is formed on the wall surface at the upstream end of the recess in a cross-sectional view in a direction orthogonal to the turbine shaft. ing.

  (24) In some embodiments, in the radial turbine or the mixed flow turbine according to (23), the concave guide groove is downstream from the cross section on the hub side of the shroud-side nozzle blade toward the side portion on the shroud side. The depth of the groove is continuously reduced while moving to.

  According to at least one embodiment of the present invention, it is possible to provide a radial turbine or a mixed flow turbine that has a low risk of causing troubles such as breakage and exhibits high turbine efficiency in a wide flow rate range.

1 is a schematic meridional view for explaining a basic configuration of a radial turbine or a mixed flow turbine according to a first embodiment of the present invention. It is a schematic meridional view for explaining the structure of a radial turbine or a mixed flow turbine according to the first embodiment of the present invention. It is an enlarged view of the a part (nozzle part) in FIG. It is a schematic arrow view of the AA direction in FIG. It is the schematic perspective view which showed the nozzle part of the radial turbine or mixed flow turbine corresponding to 1st Embodiment of this invention. It is the schematic perspective view which showed the nozzle part of the radial turbine or mixed flow turbine corresponding to 1st Embodiment of this invention. It is the schematic perspective view which showed the nozzle part of the radial turbine or mixed flow turbine corresponding to 1st Embodiment of this invention, Comprising: It is the figure which showed the shape corresponding to the code | symbol AH of FIG. It is a figure for demonstrating the flow of the exhaust gas which flows out out of a shroud side nozzle flow path and a hub side nozzle flow path. It is the schematic perspective view which showed the nozzle part of the radial turbine or mixed flow turbine concerning the modification of 1st Embodiment of this invention. It is a schematic meridional view for demonstrating the radial turbine or mixed flow turbine concerning 2nd Embodiment of this invention. It is a schematic arrow view of the BB direction in FIG. It is a schematic arrow view of the AA direction in FIG. FIG. 9 is a schematic arrow view in the BB direction in FIG. 8, illustrating a modification of the shroud side nozzle blade. It is a figure for demonstrating the shape of the nozzle exit of the hub side nozzle flow path in the radial turbine or mixed flow turbine concerning 3rd Embodiment of this invention. It is a figure for demonstrating the flow of the exhaust gas which flows out out of a shroud side nozzle flow path and a hub side nozzle flow path in the radial turbine or mixed flow turbine concerning 3rd Embodiment of this invention. It is a figure for demonstrating the shape of the nozzle exit of the hub side nozzle flow path in the radial turbine or mixed flow turbine concerning 3rd-2 embodiment of this invention. It is a figure for demonstrating the flow of the exhaust gas which flows out out of a shroud side nozzle flow path and a hub side nozzle flow path in the radial turbine or mixed flow turbine concerning 3-2 embodiment of this invention. It is a schematic meridional view for demonstrating the radial turbine or mixed flow turbine concerning 4th Embodiment of this invention. It is a schematic arrow view of the BB direction in FIG. It is a schematic arrow view of the AA direction in FIG. It is an enlarged view of the nozzle part in FIG. It is a schematic meridional view for demonstrating the radial turbine or mixed flow turbine concerning 5th Embodiment of this invention. It is a schematic arrow view of the BB direction in FIG. It is an enlarged view of the wing periphery in FIG. It is a figure for demonstrating the shape of a blade front edge. It is a schematic arrow view of the AA direction in FIG. 20 concerning one Embodiment. It is a schematic arrow line view of the AA direction in FIG. 20 concerning other embodiment. It is the schematic perspective view which showed the nozzle part of the radial turbine or mixed flow turbine concerning 5th Embodiment of this invention. It is a schematic meridional view for demonstrating the radial turbine or mixed flow turbine concerning 6th Embodiment of this invention. It is an enlarged view of the wing periphery in FIG. It is a schematic meridional view for demonstrating the radial turbine or mixed flow turbine concerning 7th Embodiment of this invention. It is a schematic arrow view of the BB direction in FIG. It is a schematic arrow view of the AA direction in FIG. It is a schematic meridional view for demonstrating the radial turbine or mixed flow turbine concerning 8th Embodiment of this invention. FIG. 32 is a schematic arrow view in the BB direction in FIG. 31. It is a schematic arrow view of the AA direction in FIG. It is a schematic meridian view for demonstrating the radial turbine or mixed flow turbine concerning 9th Embodiment of this invention. It is a schematic arrow view of the BB direction in FIG. It is a schematic arrow view of the AA direction in FIG. It is a schematic meridian view for demonstrating the radial turbine or mixed flow turbine concerning 9th-2 embodiment of this invention. It is a schematic arrow view of the BB direction in FIG. It is a schematic arrow view of the AA direction in FIG. It is a schematic meridian view for demonstrating the radial turbine or mixed flow turbine concerning 10th Embodiment of this invention. It is a schematic meridional view for demonstrating the radial turbine or mixed flow turbine concerning 11th Embodiment of this invention.

Hereinafter, embodiments of the present invention will be described in more detail based on the drawings.
However, the scope of the present invention is not limited to the following embodiments. The dimensions, materials, shapes, relative arrangements, and the like of the component parts described in the following embodiments are not merely intended to limit the scope of the present invention, but are merely illustrative examples.

<First Embodiment>
FIG. 1 is a schematic meridional view for explaining a basic configuration of a radial turbine or a mixed flow turbine according to the first embodiment of the present invention. FIG. 2 is a schematic meridional view for explaining the structure of the radial turbine or the mixed flow turbine according to the first embodiment of the present invention. FIG. 3 is an enlarged view of a portion (nozzle portion) in FIG. 4 is a schematic arrow view showing an AA cross section in FIG. 2.
As shown in FIG. 2, the radial turbine or mixed flow turbine 1 a according to the first embodiment includes a turbine rotor blade 5, a casing 8, a dividing wall 10, and a flow rate adjusting mechanism 20.

  The turbine rotor blade 5 is provided so as to protrude in a radial direction from a rotating shaft 2 rotatably accommodated in a casing 8, a hub 3 fixed to one end side of the rotating shaft 2, and a peripheral surface 3 a of the hub 3. And a plurality of wings 4 formed. The hub 3 has a back surface 3b extending in a direction orthogonal to the turbine axis CL extending in the turbine axis direction, and a tip surface 3c parallel to the back surface 3b, and has a continuous radius toward the tip surface 3c. It is formed in a conical shape (decision cone shape) that decreases.

  As shown in FIG. 2, the casing 8 includes a turbine housing 6 having a spiral or annular scroll space formed around the turbine rotor blade 5 therein. The turbine housing 6 of the present embodiment is configured by connecting a hub side housing portion 6A and a shroud side housing portion 6B, which are respectively formed of different members, in the turbine axial direction. In the illustrated embodiment, the hub-side housing portion 6A is coupled to a bearing housing 7A that houses a bearing (not shown) that rotatably supports the rotating shaft 2. The shroud side housing portion 6B includes a scroll wall surface 16b and a shroud portion 16 on the shroud side of the scroll space.

  The dividing wall 10 extends in a direction orthogonal to the turbine axis CL, and includes a dividing portion 10A that divides the scroll space in the turbine axis direction, and a hub side abutting portion 10B formed on the inner peripheral portion of the dividing portion 10A. Become. The divided portion 10A has an annular plate shape in which a circular opening is formed at the center of a circular plate member. The hub-side contact portion 10B is a member that extends along the turbine axis CL from the inner peripheral portion of the divided portion 10A toward the hub side. Then, the spiral or annular scroll space is divided in the turbine axial direction by the dividing portion 10A, so that the shroud-side scroll flow path 12 located on the shroud side and the hub side located on the hub side in the turbine housing 6. Two scroll channels of the scroll channel 14 are formed. The arrows e1 and e2 in FIG. 2 indicate the flow of exhaust gas flowing from the shroud side scroll passage 12 and the hub side scroll passage 14 into the shroud side nozzle passage 32 and the hub side nozzle passage 34, which will be described later, on the meridian plane. Shows direction.

  In FIG. 1, reference numeral 9 denotes a nozzle portion. The nozzle portion 9 is an annular space formed between the outlet portions of the shroud side scroll channel 12 and the hub side scroll channel 14 and the front edge 4 a of the blade 4. In the embodiment shown in FIG. 2, the nozzle portion 9 is defined by the shroud side wall surface 16a of the shroud portion 16 and the hub side wall surface 18a of the hub side wall portion 18 of the hub side housing portion 6A. Both the shroud side wall surface 16a and the hub side wall surface 18a extend in a direction orthogonal to the turbine axis CL. The hub side wall portion 18 has substantially the same position in the turbine axial direction as the back surface 3b of the hub 3. As shown in FIG. 2, the hub side contact portion 10B and the hub side contact surface 10Bc are in contact with the hub side wall surface 18a.

  As schematically shown in FIG. 1, a plurality of shroud-side nozzle channels 32 are formed between the outlet portion of the shroud-side scroll channel 12 and the turbine blade inlet 4a. The plurality of shroud side nozzle channels 32 are arranged at equal intervals in the circumferential direction. The shroud side nozzle flow path 32 has a nozzle inlet 32 </ b> A that faces the shroud side scroll flow path 12. The exhaust gas flowing through the shroud-side scroll passage 12 is taken from the nozzle inlet 32A and guided to the turbine rotor blade inlet 4a.

  Further, as schematically shown in FIG. 1, a plurality of hub side nozzle flow paths 34 are formed between the outlet portion of the hub side scroll flow path 14 and the turbine blade inlet 4a. The plurality of hub side nozzle channels 34 are arranged at equal intervals in the circumferential direction. The hub side nozzle flow path 34 has a nozzle inlet 34 </ b> A that faces the hub side scroll flow path 14. The exhaust gas flowing through the hub-side scroll passage 14 is taken from the nozzle inlet 34A and guided to the turbine rotor blade inlet 4a.

  In the radial turbine or the mixed flow turbine 1a according to at least one embodiment of the present invention, as shown in FIG. 4, the nozzle outlets 32B of the plurality of shroud-side nozzle channels 32 and the plurality of hub-side nozzle channels 34 are arranged. Each of the nozzle outlets 34B is disposed to face the turbine rotor blade inlet 4a in the radial direction. As schematically shown in FIG. 3, each of the nozzle outlets 32 </ b> B of the plurality of shroud-side nozzle channels 32 and the nozzle outlets 34 </ b> B of the plurality of hub-side nozzle channels 34 is at the same axial position in the turbine axial direction. The annular nozzle outlet portion 30 is configured by being alternately arranged adjacent to each other in the circumferential direction.

  Each of the shroud-side nozzle flow path 32 and the hub-side nozzle flow path 34 is a nozzle-like throttle configured such that the flow area of the nozzle outlets 32B and 34B is smaller than the flow area of the nozzle inlets 32A and 34A. It is a flow path. As a result, the exhaust gas passing through the shroud-side nozzle passage 32 and the hub-side nozzle passage 34 is accelerated and guided to the turbine rotor blade inlet 4a.

  As the cross-sectional shapes of the nozzle inlets 32A and 32B of the shroud-side nozzle channel 32 and the hub-side nozzle channel 34, various shapes such as an ellipse, an ellipse, a rectangle, and a trapezoid can be adopted. The cross-sectional shapes of the nozzle outlets 32B and 34B are not particularly limited, but the nozzle outlets 32B and 34B may be formed over substantially the entire width of the nozzle portion 9 in the turbine axial direction. That is, the nozzle outlets 32 </ b> B and 34 </ b> B may be formed over the entire height of the leading edge 4 a of the blade 4.

  According to the radial turbine or the mixed flow turbine 1a of the present embodiment configured as described above, as described above, the nozzle outlets 32B of the plurality of shroud-side nozzle channels 32 and the nozzle outlets of the plurality of hub-side nozzle channels 34. Each of 34B is alternately arrange | positioned in the circumferential direction in the same axial direction position in a turbine axial direction. That is, the nozzle outlets 32B and 34B of these two nozzle channels are not adjacent in the turbine axial direction. For this reason, compared with what the nozzle exit of two scroll flow paths as disclosed by patent document 2 adjoins in the turbine axial direction, the other nozzle exit where pressure is low from one nozzle outlet where pressure is high The backflow phenomenon in which the exhaust gas flows to the outside is suppressed. Thereby, the fall of the turbine efficiency accompanying generation | occurrence | production of a pressure loss can be prevented.

  Also, according to the radial turbine or mixed flow turbine 1a of the present embodiment, unlike the variable capacity turbine provided with a variable nozzle as disclosed in Patent Document 1, a movable member such as a variable nozzle is provided in the nozzle portion 9. I can't. For this reason, the problem of the prior art that turbine efficiency falls by exhaust gas leaking and flowing from the clearance gap between a movable member and a wall surface does not arise. In addition, since no movable member is provided in the nozzle portion 9 through which high-speed and high-temperature exhaust gas flows, the risk of damage and the like is low, and structural reliability is high.

  In some embodiments, as shown in FIG. 1, the radial turbine or the mixed flow turbine 1 a adjusts the flow rate of the exhaust gas flowing through at least one of the shroud side scroll passage 12 and the hub side scroll passage 14. A possible flow rate adjusting mechanism 20 is further provided.

  In the illustrated embodiment, the shroud-side exhaust gas in which exhaust gas discharged from the engine (not shown) branches from the exhaust pipe 21 and the exhaust pipe 21 in the shroud-side scroll flow path 12 and the hub-side scroll flow path 14 described above. It is configured to be supplied through the pipe 23 and the hub side exhaust pipe 25. The shroud side exhaust pipe 23 that supplies exhaust gas to the shroud side scroll flow path 12 is provided with a shroud side flow rate adjustment valve 22 that can adjust the flow area of the shroud side exhaust pipe 23. A hub side flow rate adjusting valve 24 capable of adjusting the flow area of the hub side exhaust pipe 25 is disposed in the hub side exhaust pipe 25 that supplies exhaust gas to the hub side scroll flow path 14. The flow rate of the exhaust gas flowing through the shroud-side scroll passage 12 and the hub-side scroll passage 14 can be adjusted by adjusting the valve openings of the shroud-side flow adjustment valve 22 and the hub-side flow adjustment valve 24. It has become.

  In other words, in the illustrated embodiment, the above-described flow rate adjustment mechanism 20 includes a shroud side flow rate adjustment valve 22 and a hub side flow rate adjustment valve 24.

  Although not shown, the shroud-side flow rate adjusting valve 22 and the hub-side flow rate adjusting valve 24 are arranged not in the shroud-side exhaust pipe 23 and the hub-side exhaust pipe 25 but in the internal space of the shroud-side scroll channel 12 and the hub-side scroll channel 14. You may arrange in. The flow volume of the exhaust gas flowing through the shroud-side scroll passage 12 and the hub-side scroll passage 14 is adjusted by adjusting the passage areas of the shroud-side scroll passage 12 and the hub-side scroll passage 14. May be.

  According to the radial turbine or the mixed flow turbine 1a of such an embodiment, the flow rate adjusting mechanism 20 adjusts the flow rate of the exhaust gas flowing through at least one of the shroud side scroll channel 12 and the hub side scroll channel 14. I can do it. For example, the flow rate adjusting mechanism 20 can control the exhaust gas corresponding to the design flow rate to flow in both scroll passages at the maximum flow rate. Further, the exhaust gas can be controlled to flow only through one of the scroll channels at the minimum flow rate. Further, at the intermediate flow rate, it is possible to control the exhaust gas corresponding to the design flow rate to flow through one scroll flow path and adjust the flow rate of the exhaust gas flowing through the other scroll flow path. Therefore, by providing such a flow rate adjusting mechanism 20, a variable mechanism capable of realizing high turbine efficiency in a wide flow rate range from the minimum flow rate to the maximum flow rate can be configured.

Although not particularly limited, the flow passage area of the nozzle outlet 32B of the shroud-side nozzle flow passage 32 and the flow passage area of the nozzle outlet 34B of the hub-side nozzle flow passage 34 may be different from each other. . In the embodiment shown in FIG. 5A, the circumferential width (nozzle pitch P2) of the nozzle outlet 34B of the hub side nozzle flow path 34 is larger than the circumferential width (nozzle pitch P1) of the nozzle outlet 32B of the shroud side nozzle flow path 32. Is also formed small. The nozzle outlet 32B of the above-described shroud-side nozzle passage 32 is configured to have a larger passage area than the nozzle outlet 34B of the hub-side nozzle passage 34.
In this way, the flow passage area of the nozzle outlet 32B of the shroud-side nozzle flow passage 32 and the flow passage area of the nozzle outlet 34B of the hub-side nozzle flow passage 34 are formed to be different from each other, so that the shroud-side nozzle flow passage is formed. Nozzle characteristics can be made different between the nozzle 32 and the hub side nozzle passage 34. Therefore, for example, at an intermediate flow rate, turbine efficiency can be improved by appropriately controlling whether the exhaust gas flows through the shroud-side nozzle passage 32 or the hub-side nozzle passage 34. Further, for example, the exhaust gas flow rate can be adjusted in a wider flow range by configuring the exhaust gas to flow only through the nozzle flow channel having the smaller flow channel area at the nozzle outlet at the minimum flow rate.

  Next, the structural shapes of the shroud side nozzle flow path 32 and the hub side nozzle flow path 34 in the present embodiment will be described. 5A and 5B are schematic perspective views showing a nozzle portion of a radial turbine or a mixed flow turbine corresponding to the first embodiment of the present invention. FIG. 5A shows an embodiment in which the nozzle pitch P1 of the shroud-side nozzle passage 32 and the nozzle pitch P2 of the hub-side nozzle passage 34 are different, and corresponds to FIG. FIG. 5B shows an embodiment in which the nozzle pitch P1 of the shroud side nozzle flow path 32 and the nozzle pitch P2 of the hub side nozzle flow path 34 are the same. Here, the nozzle pitch is defined as the circumferential distance of the nozzle outlet. FIG. 5C is a schematic perspective view showing a nozzle portion of the radial turbine or mixed flow turbine of FIG. 5B and shows shapes corresponding to reference signs A to H of FIG.

  As shown in FIGS. 5A and 5B, the radial turbine or mixed flow turbine 1a of the present embodiment is spaced in the circumferential direction between the inner peripheral portion of the divided portion 10A and the shroud side wall surface 16a of the casing 8. A plurality of shroud side nozzle blades 17 to be formed are provided. The shroud side nozzle blade 17 extends from the inner peripheral portion of the divided portion 10A to the shroud side along the turbine axis CL. The shroud side nozzle blade 17 is connected to the inner peripheral portion of the divided portion 10A at the hub side cross section (side surface portion) 17c, and is connected to the shroud side wall surface 16a at the shroud side surface portion 17d. The shroud side nozzle blade 17 has a leading edge shape and a trailing edge shape formed substantially parallel to the turbine axis CL in the meridional view. Further, as shown in FIG. 4, the shroud-side nozzle blade 17 includes a pressure surface 17S1 oriented on the outer peripheral side and a negative pressure surface 17S2 oriented on the inner peripheral side in a cross-sectional view perpendicular to the turbine axis CL. It has a wing-shaped outer surface shape having two peripheral surfaces. Further, the front end portion 17A is inclined in the circumferential direction so as to be located upstream of the rear end portion 17B in the rotation direction R of the rotary shaft 2.

  The shroud-side nozzle flow path 32 includes an inner peripheral portion of the divided portion 10A, a pressure surface 17S1 of one shroud-side nozzle blade 17 adjacent in the circumferential direction, and a negative pressure surface 17S2 of the other shroud-side nozzle blade 17; The shroud side space 17s is defined by the shroud side wall surface 16a of the casing 8 (see FIGS. 5A and 5B).

  Further, in the radial turbine or the mixed flow turbine 1a of the present embodiment, as shown in FIGS. 5A and 5B, the groove portion 10Bd is formed on the hub side contact surface 10Bc (see FIG. 2) of the hub side contact portion 10B. Has been. A hub-side space 19s is defined by the groove 10Bd and the hub side wall surface 18a. Further, inside the shroud-side nozzle blade 17, a hub-side cross section 17c (see FIG. 2) connected to the inner peripheral portion of the divided portion 10A and a hollow portion 17h having an opening at the rear end portion 17B are formed. The hollow portion 17h is formed in a through-hole shape formed inside the shroud-side nozzle blade 17 or in a groove shape when the shroud-side nozzle blade 17 is viewed from the hub side.

  As shown in FIGS. 5A and 5B, the hub-side nozzle flow path 34 includes the hub-side space 19s and the hollow portion 17h that communicates with the hub-side space 19s.

  The nozzle inlet 34A of the hub side nozzle flow path 34 is formed on the outer peripheral end face 10Ba located on the outer peripheral side of the hub side contact portion 10B when the hub side contact portion 10B is viewed from the turbine axial direction. As shown in FIG. 2, the outer peripheral end face 10Ba extends substantially in parallel to the nozzle outlet 34B opened at the rear end 17B of the shroud-side nozzle blade 17 in the meridian view.

  The nozzle outlet 34B of the hub side nozzle flow path 34 is formed at the inner peripheral end (rear end portion 17B) of the shroud side nozzle blade 17 when the shroud side nozzle blade 17 is viewed from the turbine axial direction. The nozzle outlet 34B of the hub side nozzle flow path 34 is formed substantially parallel to the turbine axial direction in meridional view. Further, as shown in FIG. 4, it is defined inside two rear ends 17 a and 17 b formed in the rear end portion 17 </ b> B of the shroud-side nozzle blade 17 in a cross-sectional view in a direction orthogonal to the turbine axis. In the illustrated embodiment, the two rear ends 17a and 17b are formed at positions separated from the turbine axis CL by a distance R1 in the radial direction in a cross-sectional view in a direction orthogonal to the turbine axis. An annular channel 33 that is continuous in the circumferential direction is formed between the two rear ends 17 a and 17 b and the outer peripheral edge 3 d of the hub 3.

FIG. 6 is a schematic arrow view showing the AA cross section in FIG. 2 and is a view for explaining the flow of exhaust gas flowing out from the shroud side nozzle flow path and the hub side nozzle flow path.
6 indicates the flow direction of the flow f1 of the exhaust gas flowing out from the nozzle outlet 32B of the shroud side nozzle flow path 32 to the annular flow path 33. Reference numeral f <b> 2 indicates the flow of exhaust gas flowing out from the nozzle outlet 34 </ b> B of the hub side nozzle flow path 34 to the annular flow path 33.

  In the radial turbine or mixed flow turbine 1a of this embodiment, as shown in FIG. 6, the nozzle outlets 32B of the plurality of shroud-side nozzle channels 32 formed alternately adjacent to each other in the circumferential direction, and the plurality of hub sides By exhaust gas flowing out from the nozzle outlet 34B of the nozzle flow path 34, the exhaust gas flows without interruption in the circumferential direction of the annular flow path 33 and is guided to the turbine blade inlet 4a.

FIG. 7 is a schematic perspective view showing a nozzle portion of a radial turbine or a mixed flow turbine according to a modification of the first embodiment of the present invention.
The radial turbine or mixed flow turbine 1a of the present embodiment extends from the inner peripheral portion of the dividing wall 10 to the hub side and abuts against the hub side wall surface 18a, as compared with the embodiment shown in FIGS. 5A and 5B. The shape of the portion 19C (hub side contact portion 10B in FIGS. 5A and 5B) and the portion 17C (FIGS. 5A and 5B) that extends from the inner peripheral portion of the dividing wall 10 to the shroud side and contacts the shroud side wall surface 16a. The shape of the shroud side nozzle blade 17) is greatly different.

  That is, as shown in FIG. 7, the radial turbine or mixed flow turbine 1 a of the present embodiment has a shroud side wall surface 16 a of the casing 8 formed in plural at intervals in the circumferential direction on the inner peripheral portion of the dividing wall 10. A plurality of shroud-side nozzle portions 17C that come into contact with each other, and a plurality of hub-side nozzle portions 19C that come into contact with the hub side wall surface 18a of the casing 8 and that are formed at intervals in the circumferential direction on the inner peripheral portion of the dividing wall 10. It has. The shroud-side nozzle portion 17C is connected to the inside of the shroud-side nozzle portion 17C on the hub side from the radially outer end to the inner end, and an inlet facing the hub-side scroll passage 14 and an outlet facing the turbine blade inlet 4a. The hub side groove part 17g which has this. The hub-side nozzle portion 19C has an inlet facing the shroud-side scroll passage 12 and an outlet facing the turbine rotor blade inlet 4a on the shroud side from the radially outer end to the inner end inside the hub-side nozzle portion 19C. It has a shroud side groove 19g having The shroud side nozzle flow path 32 is formed by the shroud side wall surface 16a of the casing 8 and the two side wall surfaces 19Sa, 19Sb and the bottom wall surface 19Sc facing each other in the circumferential direction in the shroud side groove portion 19g of the hub side nozzle portion 19C. The hub side nozzle flow path 34 is formed by the hub side wall surface 18a of the casing 8 and the two side wall surfaces 17Sa, 17Sb and the bottom wall surface 17Sc facing each other in the circumferential direction in the hub side groove portion 17g of the shroud side nozzle portion 17C. The nozzle outlet 32B of the shroud side nozzle flow path 32 is composed of the outlet of the shroud side groove 19g. Further, the nozzle outlet 34B of the hub side nozzle flow path 34 is an outlet of the hub side groove portion 17g. Each of the outlets of the plurality of shroud side grooves 19g and the outlets of the plurality of hub side grooves 17g is opposed to the turbine blade inlet 4a in the radial direction, and is circumferential in the same axial position in the turbine axial direction. An annular nozzle outlet portion 30 is configured by being arranged alternately adjacent to each other.

  Thus, the radial turbine or mixed flow turbine 1a according to one embodiment of the present invention may have a shape as shown in FIG.

Second Embodiment
Next, a radial turbine or mixed flow turbine 1b according to a second embodiment of the present invention will be described with reference to FIGS. FIG. 8 is a schematic meridional view for explaining a radial turbine or a mixed flow turbine according to the second embodiment of the present invention. FIG. 9 is a schematic arrow view showing a BB cross section in FIG. 8.
Note that the radial turbine or mixed flow turbine of the present embodiment has basically the same configuration as that of the first embodiment described above. Accordingly, the same components are denoted by the same reference numerals, and detailed description thereof is omitted.

  In the radial turbine or mixed flow turbine 1b according to the second embodiment, as shown in FIG. 8, the turbine housing 6 described above has an integrated structure in which the hub side housing portion 6A and the shroud side housing portion 6B are made of the same member. Have. The dividing wall 10 is also configured as an integrated structure made of the same member as the turbine housing 6. Further, the hub side housing portion 6A according to the second embodiment does not have the hub side wall portion 18 described above, and a back plate 7B which is a member constituting the casing 8 is disposed instead. And the hub side wall surface 18a of the casing 8 mentioned above is comprised from the wall surface of the backplate 7B. The wall surface of the back plate 7B has a short radial distance between the hub side wall surface 18a and the rotary shaft 2 from the nozzle inlet 34A to the nozzle outlet 34B of the hub side nozzle channel 34, as shown in FIG. Inclined with respect to the turbine axis CL.

  A through hole 10Bh is formed in the hub side contact portion 10B of the dividing wall 10. The hub-side space 19s described above is formed by the through hole 10Bh. This through-hole 10Bh penetrates from the outer peripheral end surface 10Ba located on the outer peripheral side of the hub side contact portion 10B to the inner peripheral portion of the divided portion 10A when the hub side contact portion 10B is viewed from the turbine axial direction. Is formed. In the illustrated embodiment, the outer peripheral end face 10Ba extends in a direction substantially orthogonal to the hub side wall face 18a in meridional view. Although not shown, the outer peripheral end face 10Ba may be configured to extend along a radial direction substantially orthogonal to the turbine axis CL in meridional view.

  Further, in the radial turbine or the mixed flow turbine 1b according to the present embodiment, as shown in FIG. 8, the dividing portion 10A of the dividing wall 10 is formed at substantially the same position as the back surface 3b of the hub 3 in the turbine axial direction. Yes. The shroud-side nozzle flow path 32 extends toward the turbine rotor blade inlet 4a along a direction orthogonal to the turbine axis CL when viewed from the meridian plane. The hub side nozzle flow path 34 is formed so as to extend incline with respect to the turbine axial direction so as to extend along the direction from the turbine rotor blade inlet 4a toward the turbine rotor blade outlet 4b in the meridian view.

  According to the radial turbine or the mixed flow turbine 1b of such an embodiment, the flow e1 on the meridian plane of the exhaust gas flowing out from the shroud-side nozzle flow path 32 is made to the turbine axis CL, as in the conventional radial turbine. A substantially orthogonal radial flow can be achieved. Therefore, compared with the case where the flow of the exhaust gas flowing through the shroud side nozzle passage 32 flows along the direction inclined with respect to the turbine shaft so as to go from the shroud side to the hub side, the turning angle of the exhaust gas flow is made smaller. I can do it. As a result, pressure loss can be suppressed, and reduction in turbine efficiency can be prevented.

  Further, the turning angle of the flow e2 of the exhaust gas flowing out from the hub side nozzle flow path 34 on the meridian surface can be made smaller than that of the conventional radial turbine. For this reason, it is possible to further suppress the pressure loss and prevent the turbine efficiency from being lowered.

  Further, as described above, in the radial turbine or the mixed flow turbine 1 b according to the present embodiment, the hub side wall surface 18 a of the casing 8 is formed by the wall surface of the back plate 7 </ b> B formed of a member different from the turbine housing 6. For this reason, the radial turbine or the mixed flow turbine 1b according to the present embodiment can be manufactured by assembling and integrating the back plate 7B together with the turbine housing 6 and the like in the turbine axial direction.

  Further, in the radial turbine or the mixed flow turbine 1b according to the present embodiment, as shown in FIGS. 8 and 9, the nozzle inlet 34A of the hub side nozzle flow path 34 has an opening in the meridional view of the nozzle inlet 34A. When the maximum width is expressed as WA and the maximum width in the circumferential direction is expressed as WC, WA <WC. In other words, the nozzle inlet 34A of the present embodiment is formed such that the maximum width of the opening is longer in the circumferential direction than in the meridian plane direction (the direction along the outer peripheral end face 10Ba in the meridian plane view). The nozzle inlet 34A in the illustrated embodiment is formed in an elliptical shape having a long axis (length WC) in the circumferential direction and a short axis (length WA ') in the turbine axis direction, as shown in FIG. Has been.

  According to the radial turbine or the mixed flow turbine 1b of such an embodiment, the nozzle inlet 34A of the hub side nozzle flow path 34 is longer in the circumferential direction than the meridional surface direction, so that The length can be shortened. Thereby, the shape of the casing 8 can be made compact.

FIG. 10 is a schematic arrow view showing an AA cross section in FIG. 8.
In the radial turbine or mixed flow turbine 1b of some embodiments, as shown in FIG. 10, the nozzle outlet 32B of the above-described shroud-side nozzle passage 32 is larger than the nozzle outlet 34B of the hub-side nozzle passage 34. It has a channel area. The flow rate adjusting mechanism 20 described above is a flow rate adjusting valve that can adjust the flow area of the shroud side scroll flow path 12 or the flow area of the shroud side exhaust pipe 23 that introduces exhaust gas into the shroud side scroll flow path 12. It consists of a flow control valve that can adjust

  In the embodiment shown in FIG. 8, the flow rate adjustment valve (the shroud side flow rate adjustment valve 22) is arranged only in the shroud side exhaust pipe 23, and the flow rate adjustment valve is not arranged in the hub side exhaust pipe 25. For this reason, compared with the case where the flow path areas of both scroll flow paths are adjusted, only one flow rate adjusting valve is required, and the structure and control of the flow rate adjusting mechanism 20 can be simplified.

In addition, the nozzle outlet 32B of the shroud-side nozzle passage 32 of the present embodiment has a larger passage area than the nozzle outlet 34B of the hub-side nozzle passage 34, and the shroud-side nozzle passage 32 is the hub. More exhaust gas can flow than the side nozzle flow path 34. The flow rate adjusting mechanism 20 of the present embodiment is configured to adjust the flow rate of the exhaust gas flowing through the shroud side nozzle passage 32.
Therefore, for example, at the maximum flow rate, the shroud-side flow rate adjustment valve 22 can be fully opened, and the exhaust gas corresponding to the design flow rate can be controlled to flow from both nozzle flow paths 32 and 34. Further, at the minimum flow rate, the shroud-side flow rate adjustment valve 22 is fully closed, and the exhaust gas can be controlled to flow only from the hub-side nozzle channel 34 having a small channel area at the nozzle outlet. At the intermediate flow rate, the shroud-side flow rate adjustment valve 22 is controlled to an intermediate opening, exhaust gas corresponding to the design flow rate is caused to flow through the hub-side nozzle flow channel 34, and the shroud-side nozzle flow channel 32 having a large flow area at the nozzle outlet. It is possible to control to adjust the flow rate of the exhaust gas flowing through the. Thereby, the variable mechanism which implement | achieves high turbine efficiency in the wide flow range from the minimum flow to the maximum flow can be configured.

  FIG. 11 is a schematic arrow view in the BB direction in FIG. 8 and is a view showing a modification of the shroud side nozzle blade. The shroud side nozzle blade 17 shown in FIG. 11 corresponds to the pyramidal shroud side nozzle portion 17C having no blade head shown in FIG. In the radial turbine or mixed flow turbine 1b of the present embodiment, the shroud-side nozzle blade 17 having such a shape can also be employed.

<Third Embodiment>
Next, based on FIG.12 and FIG.13, the radial turbine or mixed flow turbine concerning 3rd Embodiment of this invention is demonstrated. FIG. 12 is a view for explaining the shape of the nozzle outlet of the hub side nozzle flow path in the radial turbine or the mixed flow turbine according to the third embodiment of the present invention. FIG. 13 is a diagram for explaining the flow of exhaust gas flowing out from the shroud side nozzle flow path and the hub side nozzle flow path in the radial turbine or the mixed flow turbine according to the third embodiment of the present invention.
The radial turbine or mixed flow turbine of the present embodiment has basically the same configuration as that of the above-described embodiment. Accordingly, the same components are denoted by the same reference numerals, and detailed description thereof is omitted.

  As shown in FIG. 12, the shroud side nozzle blade 17 of the radial turbine or the mixed flow turbine of the present embodiment has a suction surface rear end of the adjacent shroud side nozzle blade 17 ′ in a cross-sectional view perpendicular to the turbine axis. Virtually extending in a direction perpendicular to the downstream end surface 34Ba defined by the pressure surface rear end 17a and the negative pressure surface rear end 17b of the nozzle outlet 34B of the hub side nozzle flow path 34 of the shroud side nozzle blade 17 and intersecting with 17b. The nozzle outlet 34B of the hub side nozzle flow path 34 of the shroud side nozzle blade 17 is configured so that the line IL1 passes between the pressure surface rear end 17a and the suction surface rear end 17b of the shroud side nozzle blade 17.

  Here, the intersection of the virtual line IL1 and the downstream end face 34Ba is not limited to the center of the downstream end face 34Ba. The intersection of virtual line IL1 and downstream end surface 34Ba should just be comprised in the position between the pressure surface rear end 17a of the shroud side nozzle blade 17 and the suction surface rear end 17b.

  According to the radial turbine or the mixed flow turbine of such an embodiment, as shown in FIG. 13A, for example, even when exhaust gas is allowed to flow only from the hub side nozzle flow path 34 at the minimum flow rate. The exhaust gas flowing out from the hub side nozzle flow path 34 passes through the annular flow path 33 along the circumferential direction without being largely hindered by the negative pressure surface 17'S2 of the adjacent shroud side nozzle blade 17 '. It will flow. For this reason, the exhaust gas flowing out from the hub side nozzle flow path 34 flows without being interrupted in the circumferential direction, and flows from the entire annular flow path 33 into the turbine rotor blade inlet 4a.

  At the maximum flow rate, as shown in FIG. 13B, the exhaust gas flows out from the area where the nozzle outlets of both the hub side nozzle flow path 34 and the shroud side nozzle flow path 32 are combined. Preferably, the nozzle outlets 32B and 34B of the two nozzle channels 32 and 34 are preferably set so that the flow rates of the exhaust gas flowing out from the hub side nozzle channel 34 and the shroud side nozzle channel 32 are equal at the maximum flow rate. The throat widths S1 and S2 are preferably designed. Here, as shown in FIG. 13, the throat width is the shortest distance between two opposing surfaces forming the nozzle outlets 32B and 34B of the nozzle flow paths 32 and 34 in a cross-sectional view perpendicular to the turbine axis. Defined. The throat width S1 of the nozzle outlet 32B of the shroud-side nozzle passage 32 is such that the pressure surface rear end 17a of one adjacent shroud-side nozzle blade 17 and the negative pressure surface 17′S2 of the other adjacent shroud-side nozzle blade 17 ′. The shortest distance to connect. In the illustrated embodiment, the throat width S2 of the nozzle outlet 34B of the hub side nozzle flow path 34 is a distance connecting the pressure surface rear end 17a and the suction surface rear end 17b of the shroud side nozzle blade 17.

  As shown in FIG. 13B, the outflow direction of the exhaust gas differs between the hub side nozzle flow path 34 and the shroud side nozzle flow path 32. However, the flow direction of the exhaust gas flowing through the shroud side nozzle flow path 32 is restricted by the negative pressure surface 17'S2 of the adjacent shroud side nozzle blade 17 ', and flows along the negative pressure surface 17'S2. Therefore, the exhaust gas flowing out from the two nozzle flow paths 32 and 34 merges as one large exhaust gas flow without greatly disturbing the flow, and the turbine blade inlet 4a from the entire annular flow path 33 at the rotor blade inlet. Flow into.

  At the intermediate flow rate, as shown in FIG. 13C, the flow rate of the exhaust gas flowing out from the nozzle outlet 32B of the shroud-side nozzle passage 32 is slower than that at the maximum flow rate described above. However, the flow of the exhaust gas flowing out from the hub side nozzle flow path 34 narrows the flow width of the shroud side nozzle flow path 32, thereby accelerating the flow velocity of the exhaust gas flowing out from the shroud side nozzle flow path 32. The exhaust gas flowing out from the two nozzle flow paths 32 and 34 merges as one large exhaust gas flow without greatly disturbing the flow, and has an intermediate flow angle between the minimum flow rate and the maximum flow rate. Then, it flows into the turbine rotor blade inlet 4a from the entire annular flow path 33 at the rotor blade inlet.

  As described above, in the radial turbine or the mixed flow turbine according to the present embodiment, the exhaust gas is discharged from the entire annular flow path 33 of the moving blade inlet toward the turbine moving blade inlet 4a in a wide flow range from the minimum flow rate to the maximum flow rate. It can flow. Moreover, since the flow angle also changes continuously according to the change in flow rate, the control performance is the same as when the flow direction of the exhaust gas is controlled by the variable nozzle. For this reason, according to the radial turbine or the mixed flow turbine of the present embodiment, a variable mechanism that realizes high turbine efficiency can be configured in a wide flow rate range from the minimum flow rate to the maximum flow rate.

<Third Embodiment>
Next, based on FIG.14 and FIG.15, the radial turbine or mixed flow turbine concerning 3rd-2 embodiment of this invention is demonstrated. FIG. 14 is a view for explaining the shape of the nozzle outlet of the hub side nozzle flow path in the radial turbine or the mixed flow turbine according to the third to second embodiments of the present invention. FIG. 15 is a view for explaining the flow of exhaust gas flowing out from the shroud side nozzle flow path and the hub side nozzle flow path in the radial turbine or the mixed flow turbine according to the third to second embodiments of the present invention.
The radial turbine or mixed flow turbine of the present embodiment has basically the same configuration as that of the above-described embodiment. Accordingly, the same components are denoted by the same reference numerals, and detailed description thereof is omitted.

  As shown in FIG. 14, the shroud side nozzle blade 17 of the radial turbine or the mixed flow turbine of the present embodiment has a suction surface rear end of the adjacent shroud side nozzle blade 17 ′ in a cross-sectional view perpendicular to the turbine axis. In a direction orthogonal to the downstream end surface 34Bb defined as a line that intersects the pressure surface rear end 17a of the nozzle outlet 34B and the nozzle inner surface 17S3 on the negative pressure surface rear end 17b side of the hollow portion 17h at the shortest distance. The nozzle outlet 34B of the hub-side nozzle flow path 34 is configured so that the extending virtual line IL2 passes between the pressure surface rear end 17a and the negative pressure surface rear end 17b. 12 and 13, the pressure surface rear end 17a is upstream of the suction surface rear end 17b by a distance X (the rear end portion 17B side of the shroud-side nozzle blade 17). ).

  Here, the intersection of the virtual line IL2 and the downstream end face 34Ba is not limited to the center of the downstream end face 34Bb. The intersection of virtual line IL2 and downstream end surface 34Bb should just be comprised in either position between the pressure surface rear end 17a of the shroud side nozzle blade 17 and the suction surface rear end 17b.

  According to the radial turbine or the mixed flow turbine of such an embodiment, as shown in FIG. 15, the flow of the nozzle outlet 34 </ b> B with respect to the flow of the exhaust gas flowing out from the nozzle outlet 34 </ b> B of the hub side nozzle flow path 34. A flow velocity component in the vertical direction can be applied to the downstream end face 34Ba. For this reason, as shown in FIG. 15C, at the intermediate flow rate at which the exhaust gas flows out from the nozzle outlets 34B and 32B of both the hub side nozzle flow path 34 and the shroud side nozzle flow path 32, the above-described first As compared with the radial turbine or the mixed flow turbine of the third embodiment, the mixing of the exhaust gas flowing out from the two nozzle outlets 34B and 32B is promoted. Thereby, the uniformity of a flow improves and the pressure loss at the time of flowing in into the turbine blade inlet 4a can be reduced.

<Fourth embodiment>
Next, based on FIGS. 16-19, the radial turbine or mixed flow turbine 1c concerning 4th Embodiment of this invention is demonstrated. FIG. 16 is a schematic meridional view for explaining a radial turbine or mixed flow turbine 1 according to a fourth embodiment of the present invention. FIG. 17 is a schematic arrow view in the BB direction in FIG. 16. 18 is a schematic arrow view in the AA direction in FIG. FIG. 19 is an enlarged view of the nozzle portion in FIG.
The radial turbine or mixed flow turbine of the present embodiment has basically the same configuration as that of the above-described embodiment. Accordingly, the same components are denoted by the same reference numerals, and detailed description thereof is omitted.

  As shown in FIGS. 16 to 19, in the radial turbine or the mixed flow turbine 1 c according to the present embodiment, the dividing wall 10 extends in a direction perpendicular to the turbine axial direction as in the above-described embodiment, and scrolls. An annular plate-shaped divided portion 10A that divides the space, and a hub-side contact portion 10B that extends from the inner peripheral portion of the divided portion 10A toward the hub side and contacts the hub side wall surface 18a of the casing 8. . The hub side wall surface 18a of the casing 8 has a radial distance between the hub side wall surface 18a and the rotary shaft 2 that decreases from the nozzle inlet 34A to the nozzle outlet 34B of the hub-side nozzle channel 34 in the meridian view. Inclined with respect to the turbine axis CL.

  On the hub side contact surface 10Bc of the hub side contact portion 10B, a groove portion 10Bd that communicates from the outer end in the radial direction to the inner end is formed. The hub-side nozzle channel 34 described above is configured to include a space (hub-side space 19s) defined by the bottom surface of the groove portion 10Bd and the opposing side surface and the hub side wall surface 18a. That is, in the radial turbine or mixed flow turbine 1c of the present embodiment, unlike the radial turbine or mixed flow turbine 1b of the second embodiment described above, the hub side space 19s is formed from a groove instead of a through hole. Note that the symbol R2 in FIG. 16 indicates the radial distance from the nozzle inlet 34A of the hub-side nozzle passage 34 and the turbine axis CL.

  According to the radial turbine or mixed flow turbine 1c of such an embodiment, unlike the radial turbine or mixed flow turbine 1b of the second embodiment described above, without forming the through hole 10Bh in the dividing wall 10, The hub side nozzle flow path 34 can be formed by the groove 10Bd that is easy to process. When the through-hole 10Bh is formed in the dividing wall 10, it is necessary to manufacture by complicated casting or the like. However, if the groove portion 10Bd has an opening on the contact surface, it is manufactured by casting with a relatively simple core. Is possible. Even when high surface processing accuracy is required, it can be easily processed by an end mill.

  Further, in the radial turbine or mixed flow turbine 1c of the present embodiment, the shroud side surface portion 10Ab (see FIG. 19) and the shroud side wall surface 16a of the casing 8 in the inner peripheral portion of the divided portion 10A, as in the above-described embodiment. And a plurality of shroud side nozzle blades 17 formed at intervals in the circumferential direction. The shroud side nozzle flow path 32 is defined by the shroud side surface portion 10Ab in the inner peripheral portion of the divided portion 10A, the two shroud side nozzle blades 17 and 17 adjacent in the circumferential direction, and the shroud side wall surface 16a of the casing 8. The shroud side space 17s (see FIG. 18) is configured to be included. In addition, a groove-shaped or through-hole-shaped hollow portion 17h having an opening at the hub-side cross section 17c and the rear end portion 17B is formed inside the shroud-side nozzle blade 17 and connected to the divided portion 10A. The hub-side space 19s described above communicates with the through-hole-shaped hollow portion 17h. That is, in the radial turbine or mixed flow turbine 1c of the present embodiment, the hub side nozzle flow path 34 is configured by the hub side space 19s and the hollow portion 17h.

  According to the radial turbine or mixed flow turbine 1c of such an embodiment, the hub-side nozzle is formed by the above-described hub-side space 19s and the groove-shaped or through-hole-shaped hollow portion 17h formed inside the shroud-side nozzle blade 17. A flow path 34 is configured. For this reason, the exhaust gas flowing through the shroud-side nozzle passage 32 including the shroud-side space 17 s formed by the two shroud-side nozzle blades 17, 17 adjacent in the circumferential direction and the inside of the shroud-side nozzle blade 17 are formed. Exhaust gas flowing through the hub-side nozzle flow path 34 including the groove-shaped or through-hole-shaped hollow portion 17 h flows without interfering with each other and flows out into the annular flow path 33. With such a configuration, interference of the exhaust gas flowing through the two nozzle channels can be suppressed, so that pressure loss of the exhaust gas can be suppressed and turbine efficiency can be further improved.

<Fifth Embodiment>
Next, based on FIGS. 20-25, the radial turbine or mixed flow turbine 1d concerning 5th Embodiment of this invention is demonstrated. FIG. 20 is a schematic meridional view for explaining a radial turbine or a mixed flow turbine according to the fifth embodiment of the present invention. 21 is a schematic arrow view in the BB direction in FIG. FIG. 22A is an enlarged view around the wing in FIG. FIG. 22A is a view for explaining the shape of the blade leading edge. FIG. 23 is a schematic arrow view in the AA direction in FIG. 20 according to the embodiment. FIG. 24 is a schematic arrow view in the AA direction in FIG. 20 according to another embodiment. FIG. 25 is a schematic perspective view showing a nozzle portion of a radial turbine or a mixed flow turbine according to the fifth embodiment of the present invention.
The radial turbine or mixed flow turbine of the present embodiment has basically the same configuration as that of the above-described embodiment. Accordingly, the same components are denoted by the same reference numerals, and detailed description thereof is omitted.

  In the radial turbine or mixed flow turbine 1d of the present embodiment, as shown in an enlarged manner in FIGS. 20 to 25, particularly FIG. 22A, the blade 4 has a leading edge 4a located on the upstream side in the meridian view, It has a rear end 4 b located on the downstream side, an outer edge 4 c located on the radially outer side, and an inner edge 4 d located on the radially inner side and fixed to the peripheral surface 3 a of the hub 3. When the radial distance of the first intersection a1 between the inner edge 4d and the front edge 4a is RH, and the radial distance of the second intersection a2 between the outer edge 4c and the front edge 4a is represented by RS, RH <RS. Yes, the shape line of the leading edge 4a is formed in a convex shape toward the upstream side. On the other hand, the shape line of the rear end portion 17B of the shroud-side nozzle blade 17 is formed in a concave shape facing the front edge 4a in the meridian view.

  The shape of the leading edge 4a is shown in FIG. 22B. The leading edge 4a includes a curved portion 4a1 located on the hub side that is curved toward the upstream side, and a straight portion 4a2 located on the shroud side that extends linearly with the displacement point a3 as a boundary. Become. The curved portion 4a1 is formed so that the radial distance gradually decreases from the shroud side toward the hub side. The straight portions 4a2 are formed so that their radial distances are substantially equal. The shape line of the leading edge 4a is formed in a convex shape toward the upstream side, that is, the nozzle portion 9 side as a whole. The distance between the front edge 4a and the rear end portion 17B of the shroud-side nozzle blade 17 is formed substantially constant from the first intersection point a1 to the second intersection point a2 of the front edge 4a.

  The main component of the velocity component of the exhaust gas flowing out from the hub-side nozzle channel 34 is a circumferential component, but in the meridian view, it also has a radial component and an axial component, and is inclined with respect to the turbine shaft. It flows and flows into the turbine blade inlet 4a. However, in the radial turbine in which the leading edge 4a of the blade 4 has a constant radial distance, the turning angle of the exhaust gas flow in the meridional view is increased, and the exhaust gas flow is separated on the peripheral surface 3a of the hub 3 or the like. And pressure loss occurs.

  Therefore, according to the radial turbine or mixed flow turbine 1d of such an embodiment, the front edge 4a on the hub side of the blades 4 is formed so as to be inclined so that the radial distance becomes shorter toward the hub side. Further, the shape line of the rear end portion 17B of the shroud-side nozzle blade 17 where the nozzle outlet 34B of the hub-side nozzle passage 34 opens is formed in a concave shape facing the front edge 4a in the meridian view. For this reason, the turning angle of the flow of the exhaust gas flowing out from the hub side nozzle passage 34 in meridional view can be reduced, and the pressure loss due to the change in the flow angle can be reduced.

Further, in the radial turbine or mixed flow turbine 1d of the present embodiment, as shown in FIG. 23, the throat width S2 of the nozzle outlet 34B of the hub side nozzle passage 34 is changed from the shroud side to the hub side as in the above-described embodiment. You may form in a fixed width until it reaches. Preferably, as shown in FIG. 24, the throat width S2 of the nozzle outlet 34B of the hub side nozzle flow path 34 may be formed so that the throat width S2b on the hub side is wider than the throat width S2a on the shroud side. (S2a <S2b).
23 and 24 are schematic arrow views in the AA direction in FIG. 20, and conceptually display the throat widths S2, S2a, and S2b.

  In a turbine in which the flow rate of exhaust gas to be introduced fluctuates, high turbine efficiency is required in a region where the theoretical speed ratio (U / C0) is low when the flow rate is small, and in a region where the theoretical speed ratio (U / C0) is high when the flow rate is large. High turbine efficiency is required.

  In the radial turbine or mixed flow turbine 1d of the present embodiment, the shape line of the leading edge 4a of the blade 4 is formed in a convex shape toward the upstream side. Further, the shape line of the rear end portion 17B of the shroud-side nozzle blade 17 is formed in a concave shape facing the front edge 4a in the meridian view. For this reason, the leading edge 4a of the blade 4 is substantially parallel to the turbine shaft and has a substantially constant radius with the portion of the hub-side impulse turbine that is inclined with respect to the turbine shaft (reference numeral 4a1 in FIG. 22B). The shroud side reaction turbine has a large function (reference numeral 4a2 in FIG. 22B). Therefore, as shown in FIG. 25, the throat width S2 of the nozzle outlet 34B of the hub side nozzle flow path 34 is formed so that the throat width S2b on the hub side is wider than the throat width S2a on the shroud side (S2a <S2b). ), A portion of the front edge 4a on the hub side (curved portion 4a1) having a large function of an impulse turbine that exhibits high turbine efficiency in a region where the theoretical speed ratio (U / C0) is low at a small flow rate. Exhaust gas can be introduced. Also, a large flow angle causes a large flow angle of exhaust gas to flow into the shroud-side portion 4a2 of the leading edge 4a, which exhibits a high turbine efficiency in a region where the theoretical speed ratio (U / C0) is high at a large flow rate. It can be made. As a result, the turbine efficiency can be improved in a wide flow range from a small flow rate to a large flow rate.

<Sixth Embodiment>
Next, based on FIGS. 26 and 27, a radial turbine or mixed flow turbine 1e according to a sixth embodiment of the present invention will be described. FIG. 26 is a schematic meridional view for explaining a radial turbine or a mixed flow turbine according to the sixth embodiment of the present invention. FIG. 27 is an enlarged view around the wing in FIG.
The radial turbine or mixed flow turbine of the present embodiment has basically the same configuration as that of the above-described embodiment. Accordingly, the same components are denoted by the same reference numerals, and detailed description thereof is omitted.

  In particular, in the radial turbine or the mixed flow turbine 1e of the present embodiment, as shown in an enlarged manner in FIG. 27, the blade 4 includes a front edge 4a located on the upstream side, a rear end 4b located on the downstream side, and a radius. It has an outer edge 4 c located on the outer side in the direction and an inner edge 4 d located on the inner side in the radial direction and fixed to the peripheral surface 3 a of the hub 3. The leading edge 4a has a shape line composed of a certain radial distance. In the hub 3, the tangential direction L1 at the outer peripheral edge 3d of the peripheral surface 3a of the hub 3 is at an angle β (5 to 5) to the back surface 3b side of the hub 3 of the turbine rotor blade 5 with respect to the direction L2 orthogonal to the turbine axis. 30 °). The hub side wall surface 18a of the casing 8 and the hub side wall surface 18a of the hub side nozzle flow path 34 from the nozzle inlet 34A toward the nozzle outlet 34B in the meridian plane view, as in the above-described embodiment. 2 extends in a slanted manner with respect to the turbine axial direction so that the distance in the radial direction with respect to 2 is short.

  In the illustrated embodiment, the leading edge 4a of the blade 4 extends substantially parallel to the turbine axis CL, unlike the above-described fifth embodiment, in meridional view. The shape of the rear end portion 17B of the shroud side nozzle blade 17 is also formed substantially parallel to the turbine axis CL. The separation distance between the leading edge 4a and the rear end portion 17B of the shroud-side nozzle blade 17 is formed substantially constant over the entire height of the blade 4.

  The main component of the velocity component of the exhaust gas flowing out from the hub-side nozzle channel 34 is a circumferential component, but in the meridian view, it also has a radial component and an axial component, and is inclined with respect to the turbine shaft. It flows and flows into the wing 4. However, in the radial turbine in which the tangential direction at the outer peripheral edge 3d of the peripheral surface 3a of the hub 3 extends in the radial direction, the turning angle of the exhaust gas flow in the meridian view is large, and the exhaust gas flow on the hub peripheral surface. Peeling or the like occurs and pressure loss occurs.

  On the other hand, according to the radial turbine or mixed flow turbine 1e of the present embodiment, the hub 3 has a tangential direction L1 at the outer peripheral edge 3d of the peripheral surface 3a of the hub 3 with respect to a direction orthogonal to the turbine axis. The turbine rotor blade 5 is formed to be inclined at an angle β (5 to 30 °) on the back surface 3b side of the hub 3. For this reason, the turning angle of the flow f2 in the meridional view of the exhaust gas flowing out from the hub side nozzle flow path 34 can be reduced, and the pressure loss due to the flow angle change can be reduced.

<Seventh embodiment>
Next, based on FIGS. 28-30, the radial turbine or mixed flow turbine 1f concerning 7th Embodiment of this invention is demonstrated. FIG. 28 is a schematic meridional view for explaining a radial turbine or a mixed flow turbine according to the seventh embodiment of the present invention. FIG. 29 is a schematic arrow view in the BB direction in FIG. 30 is a schematic arrow view in the AA direction in FIG.
The radial turbine or mixed flow turbine of the present embodiment has basically the same configuration as that of the above-described embodiment. Accordingly, the same components are denoted by the same reference numerals, and detailed description thereof is omitted.

As shown in FIGS. 28 to 30, the radial turbine or the mixed flow turbine 1 f of the present embodiment has a dividing wall 10 that extends in a direction perpendicular to the turbine axis CL, and divides the scroll space 10 </ b> A. And a shroud-side contact portion 10 </ b> C that extends from the inner peripheral portion of the divided portion 10 </ b> A toward the shroud side and contacts the shroud side wall surface 16 a of the shroud portion 16 of the casing 8. And the shroud side nozzle flow path 32 includes at least a space defined by the shroud side wall surface 16a of the shroud portion 16 and a groove portion formed on the contact surface of the shroud side contact portion 10C with the shroud side wall surface 16a. Configured.
A plurality of hub side nozzle blades 19 are concentrically arranged between the hub side scroll passage 14 and the turbine rotor blade 5. The hub-side nozzle flow path 34 is formed between two hub-side nozzle blades 19 adjacent in the circumferential direction.

  Even with the radial turbine or the mixed flow turbine 1f of the present embodiment configured as described above, it is possible to obtain the same effects as those of the above-described embodiment.

<Eighth Embodiment>
Next, based on FIGS. 31-33, the radial turbine or mixed flow turbine 1g concerning 8th Embodiment of this invention is demonstrated. FIG. 31 is a schematic meridional view for explaining a radial turbine or a mixed flow turbine according to the eighth embodiment of the present invention. FIG. 32 is a schematic arrow view in the BB direction in FIG. 31. FIG. 33 is a schematic arrow view in the AA direction in FIG. 31.
The radial turbine or mixed flow turbine of the present embodiment has basically the same configuration as that of the above-described embodiment. Accordingly, the same components are denoted by the same reference numerals, and detailed description thereof is omitted.

As schematically shown in FIGS. 31 to 33, particularly FIG. 33, in the radial turbine or mixed flow turbine 1 g of the present embodiment, unlike the above-described embodiment, the nozzle outlet 34 </ b> B of the hub-side nozzle flow path 34. The flow path area is formed larger than the flow path area of the nozzle outlet 32B of the shroud-side nozzle flow path 32.
In other words, the flow area of the nozzle outlets 32B and 34B of the two nozzle flow paths 32 and 34 in this embodiment is opposite to that of the second embodiment described above.

  Further, as shown in FIG. 31, in the radial turbine or the mixed flow turbine 1g of the present embodiment, the flow rate adjusting valve (hub side flow rate adjusting valve 24) is disposed only in the hub side exhaust pipe 25, and the shroud side exhaust pipe 23 is provided. Is not provided with a flow regulating valve. That is, in the present embodiment, the flow rate adjusting mechanism 20 includes the hub side flow rate adjusting valve 24 that can adjust the flow path area of the hub side exhaust pipe 25 that introduces exhaust gas into the hub side scroll flow channel 14.

  According to such an embodiment, the nozzle outlet 34 </ b> B of the hub side nozzle flow path 34 has a larger flow area than the nozzle outlet 32 </ b> B of the shroud side nozzle flow path 32. By adjusting the channel area of the hub-side scroll channel 14 that introduces the flow rate, the flow rate can be adjusted in a wider range.

  Further, for example, as in the above-described embodiment, exhaust gas is allowed to flow only from the shroud side nozzle flow path 32 having a small flow area at the nozzle outlet at the minimum flow rate, and the design flow rate is equivalent from both nozzle flow paths 32 and 34 at the maximum flow rate. The exhaust gas corresponding to the design flow rate is caused to flow through the shroud-side nozzle passage 32 and the flow rate of the exhaust gas flowing through the hub-side nozzle passage 34 having a large passage area at the nozzle outlet is adjusted at the intermediate flow rate. Thus, it is possible to configure a variable mechanism that realizes high turbine efficiency in a wide flow range from the minimum flow rate to the maximum flow rate. In addition, at the time of a large flow rate, the function as an impulse turbine that exhibits high turbine efficiency in a region where the theoretical speed ratio (U / C0) is low as described in the fifth embodiment can be exhibited more remarkably. It is like that.

<Ninth Embodiment>
Next, based on FIGS. 34-36, the radial turbine or mixed flow turbine 1h concerning 9th Embodiment of this invention is demonstrated. FIG. 34 is a schematic meridional view for explaining a radial turbine or a mixed flow turbine according to the ninth embodiment of the present invention. FIG. 35 is a schematic arrow view in the BB direction in FIG. FIG. 36 is a schematic arrow view in the AA direction in FIG.
Note that the radial turbine or mixed flow turbine of the present embodiment has basically the same configuration as the above-described embodiment, particularly the above-described second embodiment. Accordingly, the same components are denoted by the same reference numerals, and detailed description thereof is omitted.

  As shown in FIGS. 34 to 36, the radial turbine or mixed flow turbine 1h according to the present embodiment is located inside the shroud-side nozzle blade 17 with respect to the radial turbine or mixed flow turbine 1b according to the second embodiment described above. The hollow portion 17h is not formed. The hub side nozzle flow path 34 of the present embodiment is configured only by the hub side space 19s formed of the through hole 10Bh formed in the hub side contact portion 10B of the dividing wall 10. In this embodiment, instead of the hollow portion 17h not being formed inside the shroud-side nozzle blade 17, a concave portion 17G is formed on the pressure surface 17S1 of the shroud-side nozzle blade 17. The concave portion 17G has such a shape that a part of the pressure surface 17S1 of the shroud-side nozzle blade 17 is scraped from the downstream side of the front end portion 17A to the rear end portion 17B in a cross-sectional view in a direction orthogonal to the turbine axis. . The recess 17G is configured to guide the exhaust gas flowing out from the nozzle outlet 34B of the hub side nozzle flow path 34 in a direction orthogonal to the front edge 4a of the blade 4.

<Ninth Embodiment>
Next, based on FIGS. 37-39, the radial turbine or mixed flow turbine 1i concerning 9th-2 embodiment of this invention is demonstrated. FIG. 37 is a schematic meridional view for explaining a radial turbine or a mixed flow turbine according to a ninth to second embodiment of the present invention. FIG. 38 is a schematic arrow view in the BB direction in FIG. FIG. 39 is a schematic arrow view in the AA direction in FIG.
Note that the radial turbine or mixed flow turbine of the present embodiment has basically the same configuration as the above-described embodiment, particularly the above-described fourth embodiment. Accordingly, the same components are denoted by the same reference numerals, and detailed description thereof is omitted.

  As shown in FIGS. 37 to 39, the radial turbine or mixed flow turbine 1i of the present embodiment has a hollow portion in the shroud side nozzle blade 17 compared to the radial turbine or mixed flow turbine 1c of the fourth embodiment described above. 17h is not formed. The hub-side nozzle flow path 34 of the present embodiment is configured only by the hub-side space 19s formed by the groove portion 10Bd formed in the hub-side contact surface 10Bc of the hub-side contact portion 10B of the dividing wall 10. In the present embodiment, instead of forming the hollow portion 17h described above inside the shroud-side nozzle blade 17, the recess 17G is formed on the pressure surface 17S1 of the shroud-side nozzle blade 17 as in the ninth embodiment described above. Is formed. The recess 17G is configured to guide the exhaust gas flowing out from the nozzle outlet 34B of the hub side nozzle flow path 34 in a direction orthogonal to the front edge 4a of the blade 4.

  The difference between the present embodiment and the ninth embodiment described above is that, in this embodiment, the hub side space 19s is formed by the groove portion 10Bd formed on the hub side contact surface of the hub side contact portion 10B of the dividing wall 10. On the other hand, in the ninth embodiment, the hub side space 19s is formed by the through hole 10Bh formed in the hub side contact portion 10B of the dividing wall 10.

  That is, in the radial turbine or mixed flow turbine 1h according to the ninth embodiment and the radial turbine or mixed flow turbine 1i according to the ninth embodiment, the dividing wall 10 is orthogonal to the turbine axis CL, as in the above-described embodiment. A ring-plate-shaped divided portion 10A that divides the scroll space, and a hub side that extends from the inner peripheral portion of the divided portion 10A toward the hub side and contacts the hub side wall surface 18a of the casing 8 It consists of contact part 10B. In addition, a plurality of shroud-side nozzle blades 17 are further provided that are formed at intervals in the circumferential direction between the inner peripheral portion of the divided portion 10 </ b> A and the shroud side wall surface 16 a of the casing 8. The shroud-side nozzle blade 17 extends from the inner peripheral portion of the divided portion 10A to the shroud side along the turbine axis CL in the meridian view, and is formed in a leading edge shape that is formed substantially parallel to the turbine axis CL. And has a blade-shaped outer surface shape having two peripheral surfaces of a pressure surface 17S1 oriented on the outer peripheral side and a negative pressure surface 17S2 oriented on the inner peripheral side in a cross-sectional view in a direction orthogonal to the turbine shaft. The nozzle inlet 34A of the hub side nozzle flow path 34 is formed on the outer peripheral end face 10Ba located on the outer periphery of the hub side contact portion 10B when the hub side contact portion 10B is viewed from the turbine axial direction. The outer peripheral end surface 10Ba extends substantially parallel to the nozzle outlet 34B in the meridian view, or rotates with the hub side wall surface 18a from the nozzle inlet 34A of the hub-side nozzle channel 34 toward the nozzle outlet 34B. It extends in a direction substantially orthogonal to the hub side wall surface 18a of the casing 8 extending so as to shorten the radial distance from the shaft 2, or is formed so as to extend along the radial direction. . The hub-side nozzle channel 34 includes a hub-side space 19s formed in a through hole shape formed in the hub-side contact portion 10B or a groove shape when the hub-side contact portion 10B is viewed from the hub side. . The nozzle outlet 34B of the hub side nozzle flow path 34 opens to the side surface portion 10Ab on the shroud side of the divided portion 10A. The pressure surface 17S1 of the shroud-side nozzle blade 17 is formed with a recess 17G for guiding the exhaust gas flowing out from the nozzle outlet 34B of the hub-side nozzle passage 34 to the turbine rotor blade inlet 4a.

  According to such an embodiment, the exhaust gas flowing out from the nozzle outlet 34B of the hub side nozzle flow path 34 is guided to the turbine blade inlet 4a by the recess 17G. For this reason, it is not necessary to form the groove-shaped or hole-shaped hollow portion 17h inside the shroud-side nozzle blade 17, and the productivity is excellent.

  In some embodiments, as shown in FIGS. 36 and 39, the wall surface of the upstream end of the recess 17G (the front end of the shroud-side nozzle blade 17 in the recess 17G) in a cross-sectional view perpendicular to the turbine axis CL. A concave guide groove 17gu is formed on the wall surface of the portion 17A.

  According to such an embodiment, the exhaust gas flowing out from the nozzle outlet 34B of the hub side nozzle flow path 34 flows along the concave guide groove 17gu toward the turbine rotor blade inlet 4a. The exhaust gas flowing out from the nozzle outlet 34B of 34 can be smoothly guided to the turbine blade inlet 4a. In the illustrated embodiment, the cross section of the guide groove 17 gu is formed in a U shape so that the ventilation resistance is reduced.

  In some embodiments, the concave guide groove 17 gu is provided downstream from the hub-side cross section 17 c of the shroud-side nozzle blade 17 toward the shroud-side side portion 17 d, as shown in FIGS. 34 and 37. The depth of the groove is continuously reduced while moving to the side (the rear end portion 17B side of the shroud-side nozzle blade 17).

  According to such an embodiment, the ventilation resistance when the exhaust gas flowing out from the nozzle outlet 34B of the hub side nozzle flow path 34 is guided to the turbine rotor blade inlet 4a can be further reduced. .

<Tenth Embodiment>
Next, based on FIG. 40, the radial turbine or mixed flow turbine 1j concerning 10th Embodiment of this invention is demonstrated. FIG. 40 is a schematic meridional view for explaining a radial turbine or a mixed flow turbine according to the tenth embodiment of the present invention.
The radial turbine or mixed flow turbine of the present embodiment has basically the same configuration as that of the above-described embodiment. Accordingly, the same components are denoted by the same reference numerals, and detailed description thereof is omitted.

  As shown in FIG. 40, in the radial turbine or mixed flow turbine 1j of the present embodiment, the dividing wall 10 described above includes a dividing portion 10A and a hub-side abutting portion 10B formed integrally with the dividing portion 10A. Consists of The dividing wall 10 is formed of a member different from the turbine housing 6. The above-described shroud-side nozzle blade 17 is constituted by a member separate from the dividing wall 10 and the turbine housing 6. The turbine housing 6 is composed of a hub side housing portion 6A located on the hub side in the meridian view and a shroud side housing portion 6B located on the shroud side in the meridian view. The hub side housing portion 6A and the shroud side housing portion 6B are configured as separate members.

  In the illustrated embodiment, the hub-side housing portion 6A is formed with a split convex portion 13 that protrudes toward the scroll space along a direction orthogonal to the turbine axis CL. A step is formed at the tip of the divided convex portion 13, and an abutting surface 13a oriented in the turbine axial direction is formed. And the level | step difference corresponding to this is formed also in the base end part of 10 A of division | segmentation parts, and the abutting surface 10Aa oriented in the turbine axial direction is formed. Then, in a state where the abutting surfaces 10Aa of the divided convex portions 13 and the abutting surfaces 13a of the divided portions 10A are abutted with each other by fastening members such as bolts, the divided portions 10A of the divided wall 10 are attached to the turbine housing 6. Fixed. In addition, a through hole 10Bh is formed in the hub side contact portion 10B of the dividing wall 10 of the illustrated embodiment, and a hub side space 19s is formed by the through hole 10Bh. Note that the groove 10Bd described above may be formed in the hub-side contact portion 10B instead of the through-hole 10Bh, and the hub-side space 19s may be formed by the groove 10Bd.

  A butt surface 6Aa oriented in the turbine axial direction is formed at one end of the hub side housing portion 6A on the shroud side. Correspondingly, an abutting surface 6Ba oriented in the turbine axial direction is also formed at the upper end portion of the shroud side housing portion 6B. The hub-side housing portion 6A and the shroud-side housing portion 6B are fixed by fastening the abutting surface 6Aa and the abutting surface 6Ba together with a fastening member such as a bolt. Thereby, the turbine housing 6 is formed.

  The plurality of shroud side nozzle blades 17 are fixed between the shroud side wall surface 16a of the shroud portion 16 and the shroud side surface portion 10Ab in the inner peripheral portion of the divided portion 10A of the divided wall 10. Further, the above-described hollow portion 17h is formed inside the shroud-side nozzle blade 17, and the hub-side nozzle flow path 34 is configured by the hollow portion 17h and the above-described hub-side space 19s.

  According to the radial turbine or mixed flow turbine 1j of such an embodiment, the dividing wall 10, the shroud side nozzle blades 17, and the turbine housing 6 are each constituted by separate members. The turbine housing 6 includes a hub-side housing portion 6A and a shroud-side housing portion 6B that are made of different members. Then, these members such as the hub side housing portion 6A, the shroud side housing portion 6B, the dividing wall 10, the shroud side nozzle blades 17, and the back plate 7B, which are formed of different members, are assembled and integrated in the turbine axial direction. The radial turbine or mixed flow turbine of this embodiment can be assembled. For this reason, it is excellent in manufacturability.

  In some embodiments, in the radial turbine or the mixed flow turbine 1j, the above-described dividing wall 10 and the shroud side housing portion 6B are formed symmetrically with respect to the turbine axis CL. That is, the dividing wall 10 and the shroud side housing portion 6B are configured as annular members having a symmetrical shape with respect to the central axis. Further, the back plate 7B can also be formed symmetrically with respect to the turbine axis CL. Further, the plurality of shroud side nozzle blades 17 are also configured as one member formed symmetrically with respect to the turbine axis CL by connecting the plurality of shroud side nozzle blades 17 in an annular manner by a ring-shaped member. I can do it.

  According to such an embodiment, when these axially symmetric members such as the dividing wall 10 and the shroud side housing portion 6B are assembled and integrated in the turbine axial direction, they can be assembled without positioning their circumferential positions. I can do it. For this reason, it is excellent in manufacturability.

<Eleventh embodiment>
Next, based on FIG. 41, the radial turbine or mixed flow turbine 1k concerning 10th Embodiment of this invention is demonstrated. FIG. 41 is a schematic meridional view for explaining a radial turbine or a mixed flow turbine according to the tenth embodiment of the present invention.
Note that the radial turbine or mixed flow turbine of the present embodiment has basically the same configuration as that of the above-described tenth embodiment. Accordingly, the same components are denoted by the same reference numerals, and detailed description thereof is omitted.

  As shown in FIG. 41, in the radial turbine or mixed flow turbine 1k of the present embodiment, the casing 8 is elastically deformable supported by the hub side housing portion 6A, which is formed of a member different from the turbine housing 6. A first plate member 42 is included. The first plate member 42 is made of, for example, a sheet metal. The first plate member 42 has a turbine axis line so that a radial distance between the hub side wall surface 18a and the rotary shaft 2 becomes shorter from the nozzle inlet 34A of the hub side nozzle flow path 34 toward the nozzle outlet 34B in the meridian view. It has the inclined surface 42a which inclines with respect to CL, and this inclined surface 42a comprises the hub side wall surface 18a of the casing 8 mentioned above. The hub-side contact surface 10Bc of the hub-side contact portion 10B of the dividing wall 10 is configured to contact the inclined surface 42a (the hub side wall surface 18a of the casing 8) of the first plate member 42.

  According to the radial turbine or the mixed flow turbine 1k of such an embodiment, the hub side contact portion 10B of the dividing wall 10 contacts the inclined surface 42a of the first plate member 42 that can be elastically deformed. For this reason, when the dividing wall 10 formed of a member different from the turbine housing 6 is thermally deformed by the high-temperature exhaust gas, the first plate member 42 is elastically deformed to absorb the heat deformation. . Therefore, even if the dividing wall 10 and the shroud side nozzle blades 17 are configured by a member different from the turbine housing 6, a gap or the like does not occur in the hub side nozzle flow path 34 due to thermal deformation. Further, if the first plate member 42 is formed symmetrically with respect to the turbine axis CL, it is necessary to position the circumferential position when the first plate member 42 is assembled and integrated in the turbine axis direction, as in the tenth embodiment described above. As a result, the assemblability is improved.

  In some embodiments, as shown in FIG. 41, in this radial turbine or mixed flow turbine 1k, the casing 8 further includes an elastically deformable second plate member 44 fixed to the shroud-side housing portion 6B. . The second plate member 44 is made of, for example, a sheet metal. The second plate member 44 has a side surface 44a that constitutes at least a part of the shroud side wall surface 16a that extends along a direction orthogonal to the turbine axis CL when viewed from the meridian plane. The shroud-side nozzle blade 17 is configured to abut against the side surface 44 a of the second plate member 44 and be supported by the side surface 44 a and the dividing wall 10.

  According to such an embodiment, the shroud side nozzle blade 17 is supported between the second plate member 44 and the dividing wall 10 in a state where the shroud side nozzle blade 17 is in contact with the side surface 44 a of the elastically deformable second plate member 44. . For this reason, when the dividing wall 10 and the shroud side nozzle blade 17 constituted by members different from the turbine housing 6 are thermally deformed by the high-temperature exhaust gas, the second plate member 44 is elastically deformed, so that the heat deformation. Can be absorbed. Therefore, even if the dividing wall 10 and the shroud side nozzle blades 17 are configured by a member different from the turbine housing 6, a gap or the like does not occur in the hub side nozzle flow path 34 due to thermal deformation. Further, if the second plate member 44 is formed symmetrically with respect to the turbine axis CL, it is necessary to position the circumferential position when the second plate member 44 is assembled and integrated in the turbine axis direction, as in the tenth embodiment described above. As a result, the assemblability is improved.

  In the above-described embodiment, the second plate member 44 is formed in an L shape having a side surface 44a and an upper surface 44b extending in a direction substantially orthogonal to the side surface 44a in meridional view. The end edge of the side surface 44a is fixed to the shroud portion 16 of the shroud side housing portion 6B, and the end edge of the side surface 44a of the upper surface 44b is fixed to the scroll wall surface 16b of the shroud side housing portion 6B. Thereby, a space 46 is formed between the second plate member 44 and the shroud side housing portion 6B. The space 46 is located between the shroud-side scroll passage 12 and the shroud portion 16 through which high-temperature exhaust gas flows, and prevents heat of the exhaust gas flowing through the shroud-side scroll passage 12 from acting on the shroud portion 16. It functions as a heat insulating space. Therefore, the heat loss of the exhaust gas flowing through the shroud-side scroll flow path 12 due to the heating of the shroud portion 16 and the increase in enthalpy of the blade flow caused by the heat transmitted to the exhaust gas flowing through the blade 4 through the shroud portion 16 are accompanied. Various losses generated by heating the shroud portion 16 such as a decrease in the output of the turbine rotor blade 5 can be reduced. Thereby, the turbine efficiency can be improved.

<Other embodiments>
Further, in the radial turbine or mixed flow turbine of some embodiments, as shown in the above-described drawings, in particular, FIGS. 8 to 11, 26, and 27, the dividing wall 10 is in a direction orthogonal to the turbine axis CL. An annular plate-shaped divided portion 10A that extends and divides the scroll space, and a hub-side contact portion that extends from the inner peripheral portion of the divided portion 10A toward the hub side and contacts the hub side wall surface 18a of the casing 8 10B. This radial turbine or mixed flow turbine further includes a plurality of shroud side nozzle blades 17 formed at intervals in the circumferential direction between the inner peripheral portion of the divided portion 10 </ b> A and the shroud side wall surface 16 a of the casing 8. The shroud-side nozzle blade 17 has a leading edge shape that extends from the inner periphery of the divided portion 10A to the shroud side along the turbine axis CL and is formed substantially parallel to the turbine axis CL when viewed from the meridian plane. And has a blade-shaped outer surface shape having two peripheral surfaces of a pressure surface 17S1 oriented on the outer peripheral side and a negative pressure surface 17S2 oriented on the inner peripheral side in a cross-sectional view in a direction orthogonal to the turbine axis CL. The nozzle inlet 34A of the hub side nozzle flow path 34 is formed on the outer peripheral end face 10Ba located on the outer peripheral side of the hub side contact portion 10B when the hub side contact portion 10B is viewed from the turbine axial direction. The outer peripheral end surface 10Ba extends substantially parallel to the nozzle outlet 34B in the meridian view, or the hub side wall surface 18a and the rotation shaft from the nozzle inlet 34A to the nozzle outlet 34B of the hub side nozzle flow path 34. 2 is formed so as to extend in a direction substantially orthogonal to the hub side wall surface 18a of the casing 8 extending so that the radial distance from the casing 2 becomes short, or to extend along the radial direction. The hub side nozzle flow path 34 has a hub side space 19s formed in a through hole shape formed inside the dividing wall 10B or a groove shape when the dividing wall 10B is viewed from the hub side, and the hub side space 19s. It includes a through-hole shape formed inside the shroud-side nozzle blade 17 that communicates, or a hollow portion 17h that is formed in a groove shape when the shroud-side nozzle blade 17 is viewed from the hub side. The nozzle outlet 34B of the hub-side nozzle flow path 34 is connected to the inner peripheral end (rear end 17B) of the shroud-side nozzle blade 17 when the shroud-side nozzle blade 17 is viewed from the turbine axial direction. It is formed between the two rear ends 17a and 17b formed at the rear end portion 17B of the shroud-side nozzle blade 17 in a cross-sectional view in a direction perpendicular to the turbine axis CL. The The shroud side nozzle flow path 32 includes a shroud side space 17 s defined by the inner peripheral portion of the divided portion 10 </ b> A, two shroud side nozzle blades 17 adjacent in the circumferential direction, and the shroud side wall surface 16 a of the casing 8. The nozzle outlet 32B of the shroud-side nozzle passage 32 has a hub-side nozzle flow in a circumferential region where the two rear ends 17a and 17b of the shroud-side nozzle blade 17 are present in a cross-sectional view in a direction orthogonal to the turbine axis CL. It is formed in a region excluding the nozzle outlet 34B of the passage 34.

  As described above, the radial turbine or the mixed flow turbine according to some embodiments of the present invention may have the shape as described above.

  Moreover, in the radial turbine or mixed flow turbine of some embodiments, as shown in the above-described drawings, particularly FIGS. 20 to 25, the dividing wall 10 extends in a direction perpendicular to the turbine axis CL, and is scrolled. An annular plate-shaped divided portion 10A that divides the space, and a hub-side contact portion 10B that extends from the inner peripheral portion of the divided portion 10A toward the hub side and contacts the hub side wall surface 18a of the casing 8. This radial turbine or mixed flow turbine further includes a plurality of shroud side nozzle blades 17 formed at intervals in the circumferential direction between the inner peripheral portion of the divided portion 10 </ b> A and the shroud side wall surface 16 a of the casing 8. The shroud-side nozzle blade 17 has a leading edge shape that extends from the inner periphery of the divided portion 10A to the shroud side along the turbine axis CL and is formed substantially parallel to the turbine axis CL when viewed from the meridian plane. And has a blade-shaped outer surface shape having two peripheral surfaces of a pressure surface 17S1 oriented on the outer peripheral side and a negative pressure surface 17S2 oriented on the inner peripheral side in a cross-sectional view in a direction orthogonal to the turbine axis CL. The nozzle inlet 34A of the hub side nozzle flow path 34 is formed on the outer peripheral end surface 10Ba located on the outer peripheral side of the hub side contact portion 10B when the hub side contact portion 10B is viewed from the turbine axial direction. The outer peripheral end surface 10Ba extends substantially parallel to the nozzle outlet 34B in the meridian view, or the hub side wall surface 18a and the rotary shaft 2 from the nozzle inlet 34A of the hub side nozzle flow path 34 toward the nozzle outlet 34B. Is formed so as to extend in a direction substantially orthogonal to the hub side wall surface 18a of the casing 8 extending so as to shorten the radial distance thereof, or to extend along the radial direction. The hub side nozzle flow path 34 has a hub side space 19s formed in a through hole shape formed inside the dividing wall 10B or a groove shape when the dividing wall 10B is viewed from the hub side, and the hub side space 19s. It includes a through-hole shape formed inside the shroud-side nozzle blade 17 that communicates, or a hollow portion 17h that is formed in a groove shape when the shroud-side nozzle blade 17 is viewed from the hub side. The nozzle outlet 34B of the hub-side nozzle flow path 34 is located at the inner peripheral end (rear end 17B) of the shroud-side nozzle blade 17 when the shroud-side nozzle blade 17 is viewed from the turbine axial direction in meridional view. The shroud-side nozzle blade is formed in a concave shape having a substantially constant separation distance with respect to the front edge 4a of the blade 4 of the turbine rotor blade 5 formed in a convex shape, and in a cross-sectional view perpendicular to the turbine axis CL. 17 is formed between two rear ends 17a and 17b formed at the rear end 17B.

  As described above, the radial turbine or the mixed flow turbine according to some embodiments of the present invention may have the shape as described above.

  As mentioned above, although the preferable form of this invention was demonstrated, this invention is not limited to said form. For example, the above-described embodiments may be combined, and various modifications can be made without departing from the object of the present invention.

  A radial turbine or mixed flow turbine according to at least one embodiment of the present invention can be suitably used as a radial turbine or mixed flow turbine such as an expansion turbine used in a turbocharger or a power generation engine, and a small gas turbine. .

1, 1a to 1k Radial turbine or mixed flow turbine 2 Rotating shaft 3 Hub 3a Peripheral surface 3b Rear surface 3c Front end surface 3d Outer peripheral edge 4 Blade 4a Front edge (turbine rotor blade inlet)
4a1 Curved portion 4a2 Straight portion 4b Trailing edge (turbine blade exit)
4c Outer edge 4d Inner edge 5 Turbine blade 6 Turbine housing 6A Hub side housing part 6Aa Abutting surface 6B Shroud side housing part 6Ba Abutting surface 7A Bearing housing 7B Back plate 8 Casing 9 Nozzle part 10 Dividing wall 10A Dividing part 10Aa Butting surface 10Ab Shroud side surface portion 10B Hub side abutting portion 10Ba Outer peripheral end surface 10Bc Hub side abutting surface 10Bd Groove portion 10Bh Through hole 10C Shroud side abutting portion 12 Shroud side scroll channel 13 Divided convex portion 13a Abutting surface 14 Hub side scroll channel 16 shroud portion 16a shroud side wall surface 16b scroll wall surface 17 shroud side nozzle blade 17C shroud side nozzle portion 17S1 pressure surface 17S2 negative pressure surface 17S3 nozzle inner surface 17A front end portion 17B rear end portion 17G recess 1 7a Pressure surface rear end 17b Negative pressure surface rear end 17c Cross section 17d on the hub side Side surface portion 17h on the shroud side Hollow portion 17s Shroud side space 17gu Guide groove 17Sa, 17Sb Side wall surface 17Sc Bottom base surface 18 Hub side wall portion 18a Hub side wall surface 19 Hub Side nozzle blade 19C Hub side nozzle portion 19g Shroud side groove portion 19s Hub side space 19Sa, 19sb Side wall surface 19Sc Bottom wall surface 20 Flow rate adjustment mechanism 21 Exhaust pipe 22 Shroud side flow rate adjustment valve 23 Shroud side exhaust pipe 24 Hub side flow rate adjustment valve 25 Hub Side exhaust pipe 30 Nozzle outlet portion 32 Shroud side nozzle flow path 32A Nozzle inlet 32B Nozzle outlet 33 Annular flow path 34 Hub side nozzle flow path 34A Nozzle inlet 34B Nozzle outlets 34Ba, 34Bb Downstream end face 42 First plate member 42a Inclined face 44 First 2 plate member 44a side surface 4 b top 46 space CL turbine axis IL1, IL2 imaginary line P1, P2 nozzle pitch R rotational direction S1, S2, S2a, S2b throat width

Claims (24)

A casing (8) including a turbine housing (6) in which a spiral or annular scroll space through which exhaust gas flows is formed;
A rotating shaft (2) rotatably accommodated in the casing (8), and a hub (3) fixed to the rotating shaft (2) and configured such that the radius continuously decreases toward the distal end side. ), And a plurality of blades (4) provided so as to protrude in the radial direction from the peripheral surface (3a) of the hub, and a turbine blade (5) comprising:
By dividing the scroll space formed around the turbine rotor blade inlet (4a) of the turbine rotor blade (5) in the turbine axial direction, the shroud side scroll channel (12) and the hub side scroll channel (14). And a dividing wall (10) forming two scroll flow paths of
Between the shroud side scroll flow path (12) and the turbine rotor blade inlet (4a), there is a nozzle inlet (32A) facing the shroud side scroll flow path (12). 12) a plurality of shroud-side nozzle channels (32) for guiding the exhaust gas flowing through the turbine rotor blade inlet (4a) are formed in the circumferential direction;
Between the hub side scroll flow path (14) and the turbine rotor blade inlet (4a), there is a nozzle inlet (34A) facing the hub side scroll flow path (14). 14) a plurality of hub side nozzle flow paths (34) for guiding the exhaust gas flowing through the turbine rotor blade inlet (4a) in the circumferential direction are formed;
Each of the nozzle outlets (32B) of the plurality of shroud-side nozzle channels (32) and the nozzle outlets (34B) of the plurality of hub-side nozzle channels (34) are connected to the turbine blade inlet (4a). A radial turbine or a mixed flow turbine, wherein the annular nozzle outlet portions (30) are configured by opposing each other in the radial direction and alternately arranged in the circumferential direction at the same axial position in the turbine axial direction.   The flow rate adjusting mechanism (20) capable of adjusting a flow rate of the exhaust gas flowing through at least one of the shroud side scroll channel (12) and the hub side scroll channel (14). Radial turbine or mixed flow turbine. The shroud side nozzle flow path (32) extends toward the turbine rotor blade inlet (4a) along a direction orthogonal to the turbine axial direction in meridional view,
The hub side nozzle flow path (34) is inclined with respect to the turbine shaft direction so as to be along a direction from the turbine blade inlet (4a) to the turbine blade outlet (4b) in the meridional view. The radial turbine or mixed flow turbine according to claim 1, wherein the radial turbine or the mixed flow turbine is formed to extend. The dividing wall (10) extends in a direction orthogonal to the turbine axis direction, and an annular plate-shaped dividing portion (10A) that divides the scroll space, and a hub from an inner peripheral portion of the dividing portion (10A). A hub side contact portion (10B) extending toward the side and contacting the hub side wall surface (18a) of the casing (8),
The hub side wall surface (18a) of the casing (8) is formed from the nozzle inlet (34A) of the hub side nozzle channel (34) toward the nozzle outlet (34B) in the meridional view. Extending so as to be inclined with respect to the turbine shaft direction so that a radial distance between the side wall surface (18a) and the rotating shaft (2) is shortened,
The hub side nozzle channel (34) includes a groove (10Bd) formed on the hub side contact surface (10Bc) of the hub side contact portion (10B) and the hub side wall surface (18a). At least a defined hub side space (19s);
A plurality of shroud side nozzle blades (17) formed at intervals in the circumferential direction between the inner peripheral portion of the divided portion (10A) and the shroud side wall surface (16a) of the casing (8);
The shroud side nozzle flow path (32) includes an inner peripheral portion of the divided portion (10A), two shroud side nozzle blades (17, 17) adjacent in the circumferential direction, and the shroud of the casing (8). 4. A radial turbine or mixed flow turbine according to claim 3, configured to include a shroud side space (17s) defined by a side wall surface (16a). Inside the shroud-side nozzle blade (17) is a groove-shaped or through-hole-shaped hollow portion having an opening in the hub-side cross section (17c) and rear end portion (17B) connected to the divided portion (10A). (17h) is formed,
The hub side nozzle flow path (34) includes the hub side space (19s) and the hollow portion (17h) communicating with the hub side space (19s) in the hub side cross section (17c). The radial turbine or mixed flow turbine according to claim 4.   The circumferential width (P1) of the nozzle outlet (34B) of the hub side nozzle flow path (34) is smaller than the circumferential width (P2) of the nozzle outlet (32B) of the shroud side nozzle flow path (32). The radial turbine or mixed flow turbine according to claim 4 or 5, wherein the radial turbine or the mixed flow turbine is formed.   The nozzle inlet (34A) of the hub side nozzle flow path (34) is represented by WA as the maximum width of the opening of the nozzle inlet (34A) in the meridional view, and WC as the maximum width of the opening along the circumferential direction. The radial turbine or mixed flow turbine according to any one of claims 4 to 6, wherein WA <WC when The shroud-side nozzle blade (17) has two circumferences of a pressure surface (17S1) oriented to the outer peripheral side and a negative pressure surface (17S2) oriented to the inner peripheral side in a cross-sectional view in a direction orthogonal to the turbine shaft. Having a wing-shaped outer surface shape having a surface;
In a cross-sectional view perpendicular to the turbine axis, it intersects the suction surface rear end (17b) of the adjacent shroud-side nozzle blade (17) and the pressure surface rear end (17a) of the nozzle outlet (34B). And an imaginary line (IL1) extending in a direction orthogonal to the downstream end surface (34Ba) defined by the suction surface rear end (17b) is between the pressure surface rear end (17a) and the suction surface rear end (17b). The radial turbine or mixed flow turbine according to claim 5, wherein the nozzle outlet (34 B) of the hub side nozzle flow path (34) is configured to pass through. The shroud-side nozzle blade (17) has two circumferences of a pressure surface (17S1) oriented to the outer peripheral side and a negative pressure surface (17S2) oriented to the inner peripheral side in a cross-sectional view in a direction orthogonal to the turbine shaft. Having a wing-shaped outer surface shape having a surface;
In a cross-sectional view perpendicular to the turbine axis, it intersects the suction surface rear end (17b) of the adjacent shroud-side nozzle blade (17) and the pressure surface rear end (17a) of the nozzle outlet (34B). And an imaginary line (IL2) extending in a direction perpendicular to the downstream end face (34Bb) defined as a line connecting the hollow part (17h) and the nozzle inner face (17S3) on the negative pressure face rear end (17b) side at the shortest distance However, the nozzle outlet (34B) of the hub side nozzle flow path (34) is configured to pass between the pressure surface rear end (17a) and the suction surface rear end (17b). The radial turbine or mixed flow turbine according to claim 5. In the meridional view, the wing (4)
A leading edge (4a) located upstream;
A trailing edge (4b) located downstream;
An outer edge (4c) located radially outward;
An inner edge (4d) located radially inward and secured to the peripheral surface (3a) of the hub (3),
The radial distance of the first intersection (a1) between the inner edge (4d) and the front edge (4a) is RH, and the second distance (a2) between the outer edge (4c) and the front edge (4a) When the radial distance is represented by RS, RH <RS, and the shape line of the front edge (4a) is formed in a convex shape toward the upstream side,
The shape line of the rear end portion (17B) of the shroud-side nozzle blade (17) is formed in a concave shape facing the front edge (4a) in the meridional view. The radial turbine or mixed flow turbine according to one item.   The nozzle outlet (34B) of the hub side nozzle flow path (34) is formed such that the throat width (S2) of the nozzle outlet (34B) is wider on the hub side than on the shroud side. The radial turbine or mixed flow turbine according to claim 10. The wing (4)
A leading edge (4a) located upstream;
A trailing edge (4b) located downstream;
An outer edge (4c) located radially outward;
An inner edge (4d) located radially inward and secured to the peripheral surface (3a) of the hub (3),
The leading edge (4a) has a shape line of a certain radial distance,
In the meridional view, the hub (3) is configured such that the tangential direction at the outer peripheral edge (3d) of the peripheral surface (3a) of the hub (3) is perpendicular to the turbine shaft. The wing (5) is formed on the back surface (3b) side of the hub (3) with an inclination of 5 to 30 °,
The hub side wall surface (18a) of the casing (8) is formed from the nozzle inlet (34A) of the hub side nozzle channel (34) toward the nozzle outlet (34B) in the meridional view. 10. The radial according to claim 4, wherein the radial extending between the side wall surface (18 a) and the rotating shaft (2) is inclined with respect to the turbine shaft direction so as to be short. Turbine or mixed flow turbine. The nozzle outlet (32B) of the shroud side nozzle channel (32) has a larger channel area than the nozzle outlet (34B) of the hub side nozzle channel (34),
The flow rate adjusting mechanism (20) adjusts the flow path area of the shroud side scroll flow path (12) or the shroud side exhaust pipe (23) for introducing the exhaust gas into the shroud side scroll flow path (12). Radial turbine or mixed flow turbine according to any one of claims 4 to 12, comprising a possible flow regulating valve (22). The dividing wall (10) includes the dividing portion (10A) and the hub-side contact portion (10B) formed integrally with the dividing portion (10A). ) Is composed of a member separate from the turbine housing (6),
The shroud side nozzle blade (17) is composed of a separate member from the dividing wall (10) and the turbine housing (6),
The turbine housing (6) includes a hub side housing part (6A) located on the hub side in the meridional view and a member separate from the hub side housing part (6A), and is located on the shroud side in the meridional view. The radial turbine or mixed flow turbine according to any one of claims 4 to 13, comprising a shroud-side housing portion (6B).   The radial turbine or mixed flow turbine according to claim 14, wherein the dividing wall (10) and the shroud-side housing part (6B) are formed to be axisymmetric with respect to the turbine axis.   The exhaust gas leaks along the back surface (3b) of the turbine rotor blade (5), in which the hub side wall surface (18a) of the casing (8) is formed of a member different from the turbine housing (6). The radial turbine or mixed flow turbine according to claim 14 or 15, comprising a wall surface of a back plate (7B) for preventing the occurrence of the failure. The casing (8) includes a first plate member (42) that is elastically deformable and is supported by the hub side housing portion (6A), which is constituted by a member different from the turbine housing (6).
The first plate member (42) has the hub side wall surface (18a) from the nozzle inlet (34A) of the hub side nozzle flow path (34) toward the nozzle outlet (34B) in the meridional view. And an inclined surface (42a) inclined with respect to the turbine axis direction so that a radial distance between the rotating shaft (2) and the rotating shaft (2) is shortened, and the inclined surface (42a) is the hub of the casing (8). Constituting the side wall surface (18a),
The radial according to claim 14 or 15, wherein the hub side contact portion (10B) of the dividing wall (10) is configured to contact the inclined surface (42a) of the first plate member (42). Turbine or mixed flow turbine. The casing (8) further includes an elastically deformable second plate member (44) fixed to the shroud side housing part (6B),
The second plate member (44) has a side surface (44a) constituting at least a part of the shroud side wall surface (16a) extending in a direction orthogonal to the turbine axis in the meridional view. ,
The shroud-side nozzle blade (17) is configured to abut on a side surface (44a) of the second plate member (42) and be supported by the side surface (44a) and the dividing wall (10). Item 18. A radial turbine or a mixed flow turbine according to Item 17. A plurality of shroud-side nozzle portions (17C) that are in contact with the shroud side wall surface (16a) of the casing (8), and are formed at a plurality of intervals in the circumferential direction on the inner peripheral portion of the dividing wall (10);
A plurality of hub side nozzle portions (19C) that abut on the hub side wall surface (18a) of the casing (8), which are formed at a plurality of intervals in the circumferential direction on the inner peripheral portion of the dividing wall (10). In addition,
The shroud-side nozzle portion (17C) is connected to the inside of the shroud-side nozzle portion (17C) on the hub side from the radially outer end to the inner end and the inlet facing the hub-side scroll channel (14). A hub side groove (17g) having an outlet facing the turbine blade inlet (4a),
The hub side nozzle part (19C) is connected to the inside of the hub side nozzle part (19C) on the shroud side from the radially outer end to the inner end and facing the shroud side scroll flow path (12). A shroud side groove (19g) having an outlet facing the turbine blade inlet (4a),
The shroud side nozzle flow path (32) has two sides facing the circumferential direction in the shroud side wall surface (16a) of the casing (8) and the shroud side groove portion (19g) of the hub side nozzle portion (19). The wall surface (19Sa, 19Sb) and the bottom wall surface (19Sc) are formed,
The hub side nozzle flow path (34) has two sides facing the circumferential direction in the hub side wall surface (18a) of the casing (8) and the hub side groove portion (17g) of the shroud side nozzle portion (17). The wall surface (17Sa, 17Sb) and the bottom wall surface (17Sc) are formed.
The nozzle outlet (32B) of the shroud side nozzle channel (32) is the outlet of the shroud side groove (19g),
The nozzle outlet (34B) of the hub side nozzle channel (34) is the outlet of the hub side groove (17g),
Each of the outlets of the plurality of shroud side grooves (19g) and the outlets of the plurality of hub side grooves (17g) is opposed to the turbine blade inlet (4a) in the radial direction, and is in the turbine axial direction. The radial turbine or mixed flow according to any one of claims 1 to 3, wherein an annular nozzle outlet (30) is configured by being alternately arranged adjacent to each other in the circumferential direction at the same axial direction position. Turbine. The dividing wall (10) extends in a direction orthogonal to the turbine axis direction, and an annular plate-shaped dividing portion (10A) that divides the scroll space, and a hub from an inner peripheral portion of the dividing portion (10A). A hub side contact portion (10B) extending toward the side and contacting the hub side wall surface (18a) of the casing (8),
A plurality of shroud side nozzle blades (17) formed at intervals in the circumferential direction between the inner peripheral portion of the divided portion (10A) and the shroud side wall surface (16a) of the casing (8); The shroud-side nozzle blade (17) extends from the inner peripheral portion of the divided portion (10A) to the shroud side along the turbine axis direction and is substantially parallel to the turbine axis direction in the meridional view. And a pressure surface (17S1) oriented to the outer peripheral side and a negative pressure surface (17S2) oriented to the inner peripheral side in a cross-sectional view perpendicular to the turbine shaft. It has a wing-shaped outer surface shape with a peripheral surface,
The nozzle inlet (34A) of the hub side nozzle channel (34) is located on the outer peripheral side of the hub side contact portion (10B) when the hub side contact portion (10B) is viewed from the turbine axial direction. The outer peripheral end face (10Ba) is formed on the positioned outer peripheral end face (10Ba), and the outer peripheral end face (10Ba) extends substantially parallel to the nozzle outlet (34B) in the meridional view, or the hub side nozzle flow path. The casing of (34) extending from the nozzle inlet (34A) toward the nozzle outlet (34B) so that a radial distance between the hub side wall surface (18a) and the rotating shaft (2) becomes shorter. (8) extending in a direction substantially orthogonal to the hub side wall surface (18a), or extending along a radial direction,
The hub-side nozzle channel (34) is formed in a through-hole shape formed inside the dividing wall (10B), or a hub-side space formed in a groove shape when the dividing wall (10B) is viewed from the hub side. (19s) and a through-hole formed inside the shroud-side nozzle blade (17) communicating with the hub-side space (19s), or the groove on the shroud-side nozzle blade (17) as viewed from the hub side. A hollow portion (17h) formed in a shape,
The nozzle outlet (34B) of the hub side nozzle passage (34) is located at the inner peripheral end of the shroud side nozzle blade (17) when the shroud side nozzle blade (17) is viewed from the turbine axial direction. And formed substantially parallel to the turbine axis direction in the meridional view and formed in the rear end portion (17B) of the shroud-side nozzle blade (17) in a cross-sectional view in a direction orthogonal to the turbine axis. Formed between two trailing edges (17a, 17b)
The shroud side nozzle flow path (32) includes an inner peripheral portion of the divided portion (10A), two shroud side nozzle blades (17, 17) adjacent in the circumferential direction, and the shroud of the casing (8). A shroud side space (17s) defined by the side wall surface (16a),
The nozzle outlet (32B) of the shroud-side nozzle flow path (32) has the two trailing edges (17a, 17b) of the shroud-side nozzle blade (17) in a cross-sectional view perpendicular to the turbine axis. The radial turbine or mixed flow turbine according to any one of claims 1 to 3, wherein the radial turbine region is formed in a region excluding the nozzle outlet (34B) of the hub side nozzle flow path (34). The dividing wall (10) extends in a direction orthogonal to the turbine axis direction, and an annular plate-shaped dividing portion (10A) that divides the scroll space, and a hub from an inner peripheral portion of the dividing portion (10A). A hub side contact portion (10B) extending toward the side and contacting the hub side wall surface (18a) of the casing (8),
A plurality of shroud side nozzle blades (17) formed at intervals in the circumferential direction between the inner peripheral portion of the divided portion (10A) and the shroud side wall surface (16a) of the casing (8); The shroud-side nozzle blade (17) extends from the inner peripheral portion of the divided portion (10A) to the shroud side along the turbine axis direction and is substantially parallel to the turbine axis direction in the meridional view. And a pressure surface (17S1) oriented to the outer peripheral side and a negative pressure surface (17S2) oriented to the inner peripheral side in a cross-sectional view perpendicular to the turbine shaft. It has a wing-shaped outer surface shape with a peripheral surface,
The nozzle inlet (34A) of the hub side nozzle channel (34) is located on the outer peripheral side of the hub side contact portion (10B) when the hub side contact portion (10B) is viewed from the turbine axial direction. The outer peripheral end face (10Ba) is formed on the positioned outer peripheral end face (10Ba), and the outer peripheral end face (10Ba) extends substantially parallel to the nozzle outlet (34B) in the meridional view, or the hub side nozzle flow path. The casing of (34) extending from the nozzle inlet (34A) toward the nozzle outlet (34B) so that a radial distance between the hub side wall surface (18a) and the rotating shaft (2) becomes shorter. (8) extending in a direction substantially orthogonal to the hub side wall surface (18a), or extending along a radial direction,
The hub-side nozzle channel (34) is formed in a through-hole shape formed inside the dividing wall (10B), or a hub-side space formed in a groove shape when the dividing wall (10B) is viewed from the hub side. (19s) and a through-hole formed inside the shroud-side nozzle blade (17) communicating with the hub-side space (19s), or the groove on the shroud-side nozzle blade (17) as viewed from the hub side. A hollow portion (17h) formed in a shape,
The nozzle outlet (34B) of the hub side nozzle flow path (34) is located at the inner peripheral end of the shroud side nozzle blade (17) when the shroud side nozzle blade (17) is viewed from the turbine axial direction. The turbine rotor blade (5) formed in a convex shape in the meridional view is formed in a concave shape having a substantially constant separation distance from the front edge (4a) of the blade (4), and the turbine The cross-sectional view in a direction orthogonal to the axis is formed between two rear edges (17a, 17b) formed at a rear end portion of the shroud-side nozzle blade (17). The radial turbine or mixed flow turbine according to one item. The dividing wall (10) extends in a direction orthogonal to the turbine axis direction, and an annular plate-shaped dividing portion (10A) that divides the scroll space, and a hub from an inner peripheral portion of the dividing portion (10A). A hub side contact portion (10B) extending toward the side and contacting the hub side wall surface (18a) of the casing (8),
A plurality of shroud side nozzle blades (17) formed at intervals in the circumferential direction between the inner peripheral portion of the divided portion (10A) and the shroud side wall surface (16a) of the casing (8); The shroud-side nozzle blade (17) extends from the divided portion (10A) to the shroud side along the turbine axis direction and is substantially parallel to the turbine axis direction in the meridional view. Two peripheral surfaces of a pressure surface (17S1) oriented to the outer peripheral side and a suction surface (17S2) oriented to the inner peripheral side in a cross-sectional view in a direction orthogonal to the turbine shaft. Having a wing-shaped outer surface shape,
The nozzle inlet (34A) of the hub side nozzle channel (34) is located on the outer periphery of the hub side contact portion (10B) when the hub side contact portion (10B) is viewed from the turbine axial direction. The outer peripheral end surface (10Ba) extends substantially parallel to the nozzle outlet (34B) in the meridional view, or the hub side nozzle channel ( 34) The casing (34) extending from the nozzle inlet (34A) to the nozzle outlet (34B) so that a radial distance between the hub side wall surface (18a) and the rotating shaft (2) becomes shorter. 8) extending in a direction substantially perpendicular to the hub side wall surface (18a), or extending along the radial direction,
The hub side nozzle channel (34) has a through-hole shape formed inside the hub side contact portion (10B), or a groove shape when the hub side contact portion (10B) is viewed from the hub side. Including the hub side space (19s) formed,
The nozzle outlet (34B) of the hub side nozzle flow path (34) opens to the shroud side wall surface (10c) of the divided portion (10A), and
A concave portion (17G) for guiding the exhaust gas flowing out from the nozzle outlet to the turbine rotor blade inlet (4a) is formed in the pressure surface (17S1) of the shroud side nozzle blade (17). The radial turbine or mixed flow turbine according to any one of claims 1 to 3.   The radial turbine or mixed flow turbine according to claim 22, wherein a concave guide groove (17gu) is formed in a wall surface at an upstream end of the concave portion (17G) in a cross-sectional view in a direction orthogonal to the turbine shaft. The concave guide groove (17gu) continuously moves from the hub-side cross section (17c) of the shroud-side nozzle blade (17) toward the shroud-side side surface (17d) while continuously moving to the depth of the groove. 24. A radial turbine or mixed flow turbine according to claim 23 configured to be shallow.

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