JP2013194674A - Turbine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a turbine in which turbine efficiency can be improved with a simple configuration.SOLUTION: A turbine (supercharger 1) includes: a plurality of nozzle vanes 50 which are aligned and disposed annular in a flow passage where a fluid is circulated; and a plurality of blade shafts 51 fixed to the plurality of nozzle vanes, respectively, and pivoted freely rotatable to a set of confronted shaft holes provided on a flow passage forming wall part partitioning the flow passage. An angle of the nozzle vanes is made variable within the flow passage with rotation of the blade shafts. Each of the blade shafts includes a through hole 51c penetrating the blade shaft in a rotation axis direction.

Description

  The present invention relates to a turbine having a mechanism for changing a flow rate by nozzle vanes.

  Conventionally, variable capacity turbines have been employed in turbochargers and the like. In such a turbine, for example, as shown in Patent Document 1, a plurality of nozzle vanes arranged in an annular manner in a flow path that guides exhaust gas from a scroll flow path on the turbine side to a turbine impeller are respectively fixed to a blade shaft. Yes. The blade shaft is rotatably supported in a shaft hole formed in the flow path wall surface. And if a nozzle vane changes an angle in a flow path with rotation of a blade axis | shaft, the flow area of a flow path will change and the flow volume of the fluid which distribute | circulates a flow path will be controlled.

  One end of the blade axis located on the turbine housing side is placed in a flow path through which fluid flows. For this reason, differential pressure is generated at both ends of the blade shaft, and the nozzle vane may approach the bearing housing side. Thus, it has been proved that when the nozzle vane approaches the bearing housing side, a gap is formed on the turbine housing side, and the flow of the exhaust gas at the turbine impeller outlet is disturbed. As shown in Patent Document 1, it is known that if the turbulence is large in the exhaust gas flow at the turbine impeller outlet, the efficiency of the turbine decreases.

  Therefore, in Patent Document 1, for example, the nozzle vane is pressed toward the turbine housing with a disc spring or the like to reduce the gap. Moreover, in patent document 2, the communicating path which connects from the turbine impeller exit vicinity to the axial end by the side of a turbine housing among blade blades is provided. Thus, the pressure at the end of the blade shaft on the turbine housing side is set to a pressure lower than the pressure in the exhaust nozzle, and the nozzle vane moves toward the turbine housing due to the pressure difference, and the gap is reduced.

JP 2010-24915 A JP 2009-144546 A

  As described above, according to the configurations of Patent Document 1 and Patent Document 2, the deviation of the nozzle vane toward the bearing housing can be eliminated and the turbine efficiency can be improved. However, the turbine capable of improving the turbine efficiency with a simpler configuration. Development is desired.

  Therefore, an object of the present invention is to provide a turbine capable of improving turbine efficiency with a simple configuration.

  In order to solve the above problems, a turbine according to the present invention includes a plurality of nozzle vanes arranged in an annular arrangement in a flow path through which a fluid flows, and a flow that is fixed to each of the plurality of nozzle vanes and defines the flow path. It has a plurality of blade shafts rotatably supported by a pair of opposed shaft holes provided in the passage forming wall, and the nozzle vane can change the angle in the flow passage as the blade shaft rotates. The blade shaft includes a through hole penetrating in the direction of the rotation axis.

  The turbine includes a turbine shaft provided with a turbine impeller at one end, a bearing housing that rotatably supports the turbine shaft, a turbine housing that is fixed to one end surface of the bearing housing and that houses the turbine impeller, An annular flow path formed in the turbine housing, the scroll flow path positioned radially outward of the turbine shaft relative to the turbine impeller, the turbine housing, and the turbine impeller through the turbine impeller While being connected to a scroll flow path, it is fixed to the discharge port which faces the front of the turbine impeller, and the opposed surface of the turbine housing and the bearing housing, and the communication opening degree of the scroll flow channel and the discharge port is varied. A variable vane mechanism, and the variable vane mechanism includes a pair of The flow path forming wall portion is spaced apart in the facing direction between the turbine housing and the bearing housing, and the plurality of nozzle vanes are arranged in an annular manner in the facing distance between the pair of flow path forming wall portions. The fluid introduced into the scroll flow path passes through the through hole from one end side of the blade shaft located on the turbine housing side to the other end side of the blade shaft located on the bearing housing side. You may be guided.

  The turbine impeller penetrates from the front side facing the discharge port to a back side opposite to the front side and facing one end surface of the bearing housing, and the scroll through the through hole of the blade shaft. You may provide the communicating hole which discharges the fluid guide | induced to the said bearing housing side from the flow path to the said front side from the said back side.

  According to the present invention, the turbine efficiency can be improved with a simple configuration.

It is a schematic sectional drawing of a supercharger. It is a rear view of a support ring. It is a figure which shows the state by which the drive ring was supported by the support ring. It is the elements on larger scale of FIG. It is the elements on larger scale of FIG. It is explanatory drawing for demonstrating a modification.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The dimensions, materials, and other specific numerical values shown in the embodiments are merely examples for facilitating the understanding of the invention, and do not limit the present invention unless otherwise specified. In the present specification and drawings, elements having substantially the same function and configuration are denoted by the same reference numerals, and redundant description is omitted, and elements not directly related to the present invention are not illustrated. To do.

  In this embodiment, a turbine applied to a supercharger that supercharges air supplied to the engine by the energy of exhaust gas discharged from the engine will be described. The present invention can be applied to various turbines such as a gas turbine, a steam turbine, and a wind power generator. Here, the configuration of the supercharger will be described first, and then the configuration specific to the turbine of the present embodiment will be specifically described. However, in the supercharger, the turbine and the compressor are integrated, and it is difficult to strictly separate the turbine component and the compressor component, so a turbocharger is taken as an example of a turbine.

  FIG. 1 is a schematic sectional view of the supercharger 1. In the following description, the arrow F direction shown in the figure is the front side of the supercharger 1, and the arrow R direction is the rear side of the supercharger 1. As shown in FIG. 1, the supercharger 1 includes a bearing housing 2, a turbine housing 4 fixed to a front end surface of the bearing housing 2 with a fastening bolt 3, and a fastening bolt 5 on the rear side of the bearing housing 2. And a compressor housing 6 to be fixed.

  The bearing housing 2 is formed with a bearing hole 2a penetrating in the front-rear direction of the supercharger 1, and a turbine shaft 7 is rotatably supported by the bearing hole 2a via a bearing. A turbine impeller 8 is integrally connected to one end of the turbine shaft 7, and the turbine impeller 8 is rotatably accommodated in the turbine housing 4. A compressor impeller 9 is integrally connected to the rear end portion of the turbine shaft 7, and the compressor impeller 9 is rotatably accommodated in the compressor housing 6.

  The compressor housing 6 is formed with an air inlet 10 that opens to the rear side of the supercharger 1 and is connected to an air cleaner (not shown). Further, in a state where the bearing housing 2 and the compressor housing 6 are connected by the fastening bolt 5, a diffuser flow path 11 that compresses and pressurizes air is formed by the facing surfaces of both the housings 2 and 6. The diffuser passage 11 is formed in an annular shape from the radially inner side to the outer side of the turbine shaft 7 (compressor impeller 9), and communicates with the intake port 10 via the compressor impeller 9 on the radially inner side. ing.

  Further, the compressor housing 6 is provided with an annular compressor scroll passage 12 positioned on the radially outer side of the turbine shaft 7 (compressor impeller 9) with respect to the diffuser passage 11. The compressor scroll passage 12 communicates with an intake port of an engine (not shown) and also communicates with the diffuser passage 11. Therefore, when the compressor impeller 9 rotates, fluid is sucked into the compressor housing 6 from the intake port 10, and the sucked fluid is boosted in the diffuser flow path 11 and the compressor scroll flow path 12 to be sucked into the engine intake port. Will be led to.

  Further, in a state where the bearing housing 2 and the turbine housing 4 are connected by the fastening bolt 3, a gap 14 is formed between the facing surfaces of both the housings 2 and 4. The gap 14 is a portion in which a variable flow path x in which a later-described nozzle vane 50 is arranged to flow a fluid is formed, and is formed in an annular shape from the radially inner side to the outer side of the turbine shaft 7 (turbine impeller 8). ing.

  In the turbine housing 4, an annular turbine scroll passage 15 (scroll passage) is formed that is positioned radially outward of the turbine shaft 7 relative to the turbine impeller 8. The turbine housing 4 has a discharge port 13 that communicates with the turbine scroll passage 15 via the turbine impeller 8 and faces the front of the turbine impeller 8 and is connected to an exhaust gas purification device (not shown). Yes.

  The turbine scroll passage 15 communicates with a gas inlet (not shown) through which exhaust gas discharged from the engine is guided, and also communicates with the gap 14. Therefore, the exhaust gas led from the gas inlet to the turbine scroll passage 15 is led to the discharge port 13 via the variable passage x and the turbine impeller 8, and the turbine impeller 8 is rotated in the flow process. Become. Then, the rotational force of the turbine impeller 8 is transmitted to the compressor impeller 9 via the turbine shaft 7, and the fluid is boosted by the rotational force of the compressor impeller 9 as described above, and the intake port of the engine Will be led to.

  At this time, if the flow rate of the exhaust gas guided to the turbine housing 4 changes, the rotation amounts of the turbine impeller 8 and the compressor impeller 9 change, and the pressurized fluid cannot be stably guided to the engine intake port. End up. Therefore, a variable stator vane mechanism 20 is provided in the gap 14 of the turbine housing 4 so as to be fixed to the facing surface of the turbine housing 4 and the bearing housing 2 and to vary the opening degree of communication between the turbine scroll passage 15 and the discharge port 13. It has been.

  The variable stationary blade mechanism 20 changes the flow rate of the exhaust gas guided to the turbine impeller 8 according to the flow rate of the exhaust gas. Specifically, the variable stationary blade mechanism 20 increases the flow rate of the exhaust gas guided to the turbine impeller 8 by reducing the opening of the variable flow path x when the engine speed is low and the flow rate of the exhaust gas is small. In addition, the turbine impeller 8 can be rotated even with a small flow rate. Below, the structure of the variable stationary blade mechanism 20 is demonstrated.

  As shown in FIG. 1, the variable stationary blade mechanism 20 includes a shroud ring 21 provided on the turbine housing 4 side and a nozzle ring 22 provided on the bearing housing 2 side so as to face the shroud ring 21. . The shroud ring 21 and the nozzle ring 22 form a pair of flow path forming walls that define a flow path through which exhaust gas flows. That is, the flow path forming wall portion is spaced apart in the facing direction of the turbine housing 4 and the bearing housing 2.

  Exhaust gas is guided between the pair of flow path forming wall portions. The shroud ring 21 has a thin plate ring-shaped main body 21a and a protruding portion 21b protruding from the inner peripheral edge of the main body 21a toward the discharge port 13, and the main body 21a has a thickness direction (turbine shaft). 7 are formed at equal intervals in the circumferential direction.

  Further, the nozzle ring 22 includes a thin plate ring-shaped main body 22a having the same diameter as the main body 21a of the shroud ring 21, and is opposed to the shroud ring 21 while maintaining a predetermined distance. In the nozzle ring 22, a plurality of connection pins 24 (three in the present embodiment, only one shown in FIG. 1) are rotatably inserted near the outer periphery of the main body 22 a, and the shroud is connected by the connection pins 24. The spacing between the ring 21 and the ring 21 is kept constant.

  A plurality of shaft holes 25 penetrating in the thickness direction (the axial direction of the turbine shaft 7) are formed in the main body 22 a of the nozzle ring 22 at equal intervals in the circumferential direction, and the shaft formed in the shroud ring 21. The hole 23 and the shaft hole 25 formed in the nozzle ring 22 are disposed to face each other. One end of the connecting pin 24 protrudes to the rear side of the nozzle ring 22, and the support ring 30 is fixed to the rear side of the nozzle ring 22 by caulking the protruding portion.

  FIG. 2 is a rear view of the support ring 30. As shown in FIGS. 1 and 2, the support ring 30 is formed of a cylindrical member and has a cross-sectional shape obtained by bending a thin plate-like member. The support ring 30 includes an annular flange portion 31, a cylindrical portion 32 erected on the front side from the inner peripheral edge of the flange portion 31, a flat surface portion 33 that is bent radially inward from a front end portion of the cylindrical portion 32, The fastening bolt 3 is fastened in a state where the flange portion 31 is sandwiched between opposing surfaces of the bearing housing 2 and the turbine housing 4 so that the bearing housing 2 and the turbine housing 4 are held in the turbine housing 4.

  The flat portion 33 is provided with three insertion holes 33a through which one end of the connection pin 24 can be inserted at equal intervals in the circumferential direction, and the connection pin 24 is inserted into the insertion hole 33a and caulked. As a result, the support ring 30, the shroud ring 21 and the nozzle ring 22 are integrated.

  In addition, the flat portion 33 is provided with a plurality of concave portions 34 cut out radially outward from the inner peripheral end thereof, and a support piece 35 is provided in the concave portion 34. ing. The support piece 35 includes a support portion 35a that bends rearward from the flat portion 33, and a drop-off prevention portion that is bent outward from the support portion 35a in the radial direction and is spaced apart from the flat portion 33 by a predetermined distance. 35b. The drive ring 40 is rotatably supported by the support piece 35 (see FIG. 3).

  FIG. 3 is a view showing a state in which the drive ring 40 is supported by the support ring 30. As shown in this figure, the drive ring 40 is constituted by an annular thin plate member, and the inner peripheral edge thereof is rotatably supported by the support piece 35 of the support ring 30. The drive ring 40 is formed with a plurality of engagement recesses 41 that are notched radially outward from the inner peripheral end thereof, and the engagement recess 41 has a transmission link 42. One end is engaged. One end of the drive ring 40 on the inner peripheral side is formed with one second engagement recess 43 having the same shape as the engagement recess 41, and the transmission link is connected to the second engagement recess 43. One end of a drive transmission link 44 having the same shape as 42 is engaged.

  A fitting hole 42 a is formed on the other end side of the transmission link 42, and a fitting hole 44 a is formed on the other end side of the driving transmission link 44. As shown in FIG. 1, the blade hole 51 fixed to the nozzle vane 50 is fixed in the fitting hole 42 a, and the fitting hole 44 a of the drive transmission link 44 is fixed to the fitting hole 42 a. One end of the drive shaft 45 is fitted.

  The blade shaft 51 is rotatably supported in the shaft holes 23 and 25 facing each other, and the blade shaft 51 and the nozzle vane 50 are arranged in an annular manner in the facing distance between the pair of flow path forming wall portions. The drive shaft 45 extends to the rear side of the drive ring 40, and a drive lever 46 that is driven by an actuator such as a cylinder (not shown) is integrally connected to the other end.

  Therefore, when the drive lever 46 is driven by the actuator, as shown in FIGS. 1 and 3, the drive shaft 45 rotates, and the drive transmission link 44 swings around the drive shaft 45, and this drive transmission is performed. As the link 44 swings, the drive ring 40 rotates. When the drive ring 40 is rotated in this manner, the transmission link 42 is swung by the rotation of the drive ring 40, and the blade shaft 51 is rotated along with the swing of the transmission link 42. When the blade shaft 51 rotates, the angle of the nozzle vane 50 is varied in the variable flow path x as the blade shaft 51 rotates. Thus, the area of the variable flow path x is variable.

  FIG. 4 is a partially enlarged view of FIG. As shown in FIGS. 4A and 4B, a gap S for allowing thermal deformation is provided between the shroud ring 21 and the turbine housing 4. A seal 60 is provided so that the exhaust gas does not leak from the gap S to the outlet side of the turbine impeller 8.

  At this time, as shown in the comparative example of FIG. 4B, the exhaust gas flowing through the turbine scroll passage 15 flows into the turbine housing 4 side of the blade shaft W as indicated by the dashed-dotted arrow 61a in the drawing. Then, pressure is applied to the shaft end Wa (indicated by a white arrow 62a). Further, the exhaust gas or the like that has passed through the drainage hole 63 wraps around the shaft end Wb of the blade shaft W on the bearing housing 2 side (indicated by a white arrow 62b).

  Since the pressure applied to the shaft end Wa close to the flow path of the high-pressure exhaust gas is larger than the pressure applied to the shaft end Wb, the blade shaft W and the nozzle vane 50 may approach the bearing housing 2 side. Then, the flow of exhaust gas at the outlet of the turbine impeller 8 is disturbed, and the turbine efficiency is lowered. Here, the turbine efficiency is a ratio obtained by dividing the actual work generated in the turbine shaft 7 by the theoretical work.

  Therefore, in the present embodiment, the blade shaft 51 includes a through hole 51c penetrating in the rotation axis direction, as shown in FIG. The exhaust gas on the side of the shaft end 51a located on the turbine housing 4 side flows out to the side of the shaft end 51b located on the bearing housing 2 side through the through hole 51c, as shown by a dashed line arrow 61b in the drawing. Therefore, the difference in the pressure (indicated by the white arrows 62c and 62d) applied to the shaft ends 51a and 51b of the blade shaft 51 is reduced, and the force with which the blade shaft 51 is pressed to the turbine housing 4 side is suppressed. The gap between the nozzle vane 50 and the flow path forming wall (the shroud ring 21) on the turbine housing 4 side is reduced. Thus, turbine efficiency can be improved.

  And in this embodiment, in addition to forming the through-hole 51c in the said blade axis | shaft 51, the further improvement of turbine efficiency is implement | achieved by devising the structure of the turbine impeller 8 further. Below, the structure of the turbine impeller 8 is demonstrated concretely.

  FIG. 5 is a partially enlarged view of FIG. When the bearing housing 2 and the turbine housing 4 are connected with each other, if the internal spaces of the two are kept highly sealed, they pass through the through-hole 51c of the blade shaft 51 as shown in the comparative example of FIG. Then, a part of the exhaust gas flowing out from the shaft end 51a side to the shaft end 51b side bypasses the rear side of the turbine impeller I and moves to the front side of the turbine impeller I, as indicated by a dashed line arrow 61c in the figure. It may leak into the upstream part 64 of the facing channel.

  Further, as indicated by the dashed-dotted arrow 61d, a part of the exhaust gas guided to the turbine scroll passage 15 flows out from the drain hole 63, bypasses the support ring 30, and passes through the through hole 51c. It merges with the exhaust gas flowing out from the shaft end 51a side to the shaft end 51b side. And it may leak to the upstream part 64 of the flow path which faces the front side of the turbine impeller I.

  In this case, the flow of the exhaust gas flowing from the turbine scroll passage 15 toward the turbine impeller I is disturbed, and the turbine efficiency is lowered. Therefore, the turbine impeller 8 of the present embodiment is provided with a communication hole 8a as shown in FIG.

  The communication hole 8a penetrates from the front side facing the discharge port 13 to the back side opposite to the front side and facing one end surface of the bearing housing 2 and, as shown by a dashed line arrow 61e, The exhaust gas (fluid) guided from the turbine scroll flow path 15 to the bearing housing 2 side through the through-hole 51 c of 51 is discharged from the back side of the turbine impeller 8 to the front side.

  Therefore, in the turbocharger 1 of the present embodiment, the flow rate of the exhaust gas leaking from the rear side of the turbine impeller 8 to the upstream portion 64 of the flow channel facing the front side is reduced, and the exhaust gas that rotates the turbine impeller 8 is reduced. The flow is hardly disturbed, and it is possible to suppress a decrease in turbine efficiency.

  Further, as shown in FIG. 5A, the turbine impeller 8 includes a central portion 8b in which a turbine shaft hole into which the turbine shaft 7 is inserted is formed, and a plurality of circumferentially arranged outer peripheries of the central portion 8b. It is divided into an impeller portion 8c which is a blade. In the present embodiment, one end of the communication hole 8 a is provided on the front side of the central portion 8 b of the turbine impeller 8.

  With such a configuration, the exhaust gas that has passed through the communication hole 8 a flows downstream of the turbine impeller 8, and thus does not affect the flow of exhaust gas that contributes to the rotation of the turbine impeller 8. Therefore, it is possible to effectively suppress a decrease in turbine efficiency.

  Moreover, like the modification shown in FIG. 6, one end of the front side of the turbine impeller 78 in the communication hole 78a may be provided in the impeller portion 78c instead of the central portion 78b. Even in such a configuration, the flow rate of the exhaust gas leaking from the rear side of the turbine impeller 78 to the upstream portion 64 of the flow channel facing the front side is reduced as compared with the case where the communication hole 78a is not provided. It is possible to suppress a decrease in efficiency.

  In addition, when the airtightness between the bearing housing 2 and the turbine housing 4 is not so high, or the fluid guided to the turbine housing 4 side through the through hole 51c of the blade shaft 51 can be released to the outside. If present, the communication hole does not necessarily have to be formed in the turbine impeller.

  As mentioned above, although preferred embodiment of this invention was described referring an accompanying drawing, it cannot be overemphasized that this invention is not limited to this embodiment. It will be apparent to those skilled in the art that various changes and modifications can be made within the scope of the claims, and these are naturally within the technical scope of the present invention. Is done.

  The present invention can be used for a turbine having a mechanism for changing the flow rate by nozzle vanes.

1 ... Supercharger (turbine)
2 ... Bearing housing 4 ... Turbine housing 7 ... Turbine shafts 8, 78 ... Turbine impellers 8a, 78a ... Communication hole 13 ... Discharge port 15 ... Turbine scroll channel (scroll channel)
20 ... Variable vane mechanism 23, 25 ... Shaft hole 50 ... Nozzle vane 51 ... Blade shaft 51c ... Through hole

Claims (3)

A plurality of nozzle vanes arranged in an annular arrangement in a flow path through which fluid flows, and a pair of opposed shafts fixed to each of the plurality of nozzle vanes and provided on a flow path forming wall that partitions the flow path A turbine having a plurality of blade shafts rotatably supported in holes, wherein the nozzle vane can change an angle in the flow path as the blade shaft rotates;
The blade axis is
A turbine comprising a through hole penetrating in a rotation axis direction. A turbine shaft provided with a turbine impeller at one end;
A bearing housing that rotatably supports the turbine shaft;
A turbine housing fixed to one end surface of the bearing housing and containing the turbine impeller;
An annular flow path formed in the turbine housing, the scroll flow path positioned radially outward of the turbine shaft from the turbine impeller;
A discharge port that is formed in the turbine housing and communicates with the scroll flow path via the turbine impeller, and faces the front of the turbine impeller;
A variable stationary blade mechanism that is fixed to opposed surfaces of the turbine housing and the bearing housing and that varies a communication opening degree between the scroll flow path and the discharge port;
The variable vane mechanism is
The pair of flow path forming wall portions are spaced apart from each other in the facing direction of the turbine housing and the bearing housing, and the plurality of nozzle vanes are annularly disposed in the facing distance between the pair of flow path forming wall portions. Aligned,
The fluid introduced into the scroll channel is guided through the through hole from one end side of the blade shaft located on the turbine housing side to the other end side of the blade shaft located on the bearing housing side. The turbine according to claim 1, wherein The turbine impeller is
The bearing passes from the front side facing the discharge port to the back side opposite to the front side and facing one end surface of the bearing housing, and from the scroll flow path through the through hole of the blade shaft. The turbine according to claim 2, further comprising a communication hole for discharging the fluid guided to the housing side from the back side to the front side.

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