JP6098233B2 - Variable capacity turbocharger - Google Patents

Description

The present invention relates to a variable capacity turbocharger.

  In recent years, various developments have been made on variable nozzle units equipped in variable capacity turbochargers, and the applicant of the present application has already developed and applied for variable nozzle units (Patent Documents 1 to 3, etc.). reference). The specific configuration of the variable nozzle unit according to the prior art is as follows.

  A first base ring is disposed concentrically with the turbine impeller in the turbine housing, and the second base ring is located at a position spaced apart from the first base ring in the axial direction of the turbine impeller. It is provided integrally with the base ring. A plurality of variable nozzles are arranged at equal intervals in the circumferential direction so as to surround the turbine impeller between the opposing surface of the first base ring and the opposing surface of the second base ring. Can be rotated in an opening / closing direction (opening direction and closing direction) around an axis parallel to the axis of the turbine impeller within a set rotation range (predetermined rotation range). Furthermore, a link mechanism for rotating the plurality of variable nozzles synchronously in the opening / closing direction within the rotation range is disposed in the link chamber formed on the opposite side of the opposing surface of the first base ring. ing. Here, when the plurality of variable nozzles are rotated in synchronization with the opening direction, the flow area (throat area) of the exhaust gas supplied to the turbine impeller side increases and the plurality of variable nozzles are synchronized in the closing direction. Then, the exhaust gas passage area is reduced when it is rotated.

JP 2010-65591 A JP 2009-243431 A JP 2009-243300 A

  By the way, when a variable capacity supercharger is used in a supercharged engine system, the following two characteristics (performance) are required in order to improve the fuel efficiency of the engine of the supercharged engine system. That is, the first characteristic is an increase in turbine efficiency in a low flow rate region where the engine speed is low and the exhaust gas flow rate is small (turbine efficiency in the engine low rotation region), and the second characteristic is engine rotation. This is an increase in the turbine capacity (turbine capacity in the high engine speed range) in a large flow rate region where the number is high and the exhaust gas flow rate is large.

  However, increasing the turbine efficiency in the low flow rate region and increasing the turbine capacity in the large flow rate region are in a trade-off relationship, and it has been difficult to make the two characteristics compatible.

The present invention aims at solving the aforementioned problems.

  The inventor of the present application has repeated trial and error in order to solve the above-described problems, and has found new knowledge, and has completed the present invention based on the knowledge. Before explaining the features of the present invention, the process until finding new knowledge will be described.

  A variable capacity supercharger 200 according to the conventional example shown in FIGS. 9A and 9B and a variable capacity supercharger 300 according to the invention example shown in FIGS. 10A and 10B were prototyped. Here, in the variable capacity supercharger 200 according to the conventional example, the trailing edge of each variable nozzle is the inner edge of the opposing surface of the first base ring and the second edge during rotation of each variable nozzle in the opening / closing direction. It does not protrude from the inner edge of the opposing surface of the base ring. Further, in the variable capacity supercharger 200 according to the invention example, when each variable nozzle is rotated in the opening direction to the rotation end on the opening side of the rotation range, the trailing edge of each variable nozzle is the first. 2 It protrudes radially inward with respect to the inner edge of the opposing surface of the base ring. Here, in FIGS. 9B and 10B, the variable nozzle indicated by the solid line is located at the rotation end on the open side of the rotation range, and the variable nozzle indicated by the phantom line is the rotation range. It is located at the rotation end of the closed side.

  Then, a performance test is performed on the variable capacity supercharger 200 according to the conventional example and the variable capacity supercharger 300 according to the invention example, and as a result, the relationship between the flow rate (flow rate of the test gas) and the turbine efficiency is summarized. As shown in FIG.

  That is, the variable capacity supercharger 300 according to the invention example maintains the same turbine efficiency as that of the variable capacity supercharger 200 according to the conventional example in the small flow rate range, and the variable capacity according to the conventional example in the large flow rate range. It has been found that the flow rate can be increased as compared with the type supercharger 200. That is, when the inventors of the present application rotate each variable nozzle in the opening direction to the opening side rotation end side (near the opening side rotation end) of the rotation range, the trailing edge of each variable nozzle is the second. When projecting inward in the radial direction with respect to the inner edge of the opposing surface of the base ring, increase the exhaust gas flow rate in the large flow rate region while maintaining sufficient turbine efficiency in the small flow rate region. I was able to find out that I could do it. This is considered to be because the position of the throat (apparent throat) was displaced upstream in the gas flow direction, and the throat area (apparent throat area) was increased in the large flow rate region. Further, when each variable nozzle is rotated in the opening direction to the opening end on the opening side of the rotation range, the rear edge of each variable nozzle protrudes radially inward with respect to the inner edge of the opposing surface of the first base ring. It is considered that the same phenomenon occurs even when it is configured to do so.

An aspect of the present invention is a variable capacity supercharger that supercharges air supplied to the engine side using energy of exhaust gas from an engine, and is a first one disposed in a turbine housing. A base ring, a second base ring provided at a position opposed to the first base ring in the axial direction of the turbine impeller, an opposing surface of the first base ring, and an opposing surface of the second base ring Are arranged along the circumferential direction so as to surround the turbine housing, and are capable of rotating in the opening and closing directions (opening direction and closing direction) within a set rotation range (predetermined rotation range). An annular housing recess for housing at least the inner peripheral side portion of the second base ring on the inlet side of the turbine impeller inside the turbine housing. An annular gap is formed between the outer surface and the inner peripheral surface of the second base ring of the concave of the bottle housing, the rear edge of each variable nozzle, each variable nozzle opening side of the turning range When it is turned in the opening direction to the turning end side, it protrudes radially inward with respect to the inner edge of the opposing surface of the second base ring.

  In the specification and claims of the present application, “arranged” means not only directly disposed but also indirectly disposed through another member. In addition, the term “provided” means that it is indirectly provided through another member in addition to being directly provided. Further, the “rear edge” refers to a downstream end in the exhaust gas flow direction.

According to the aspect of the present invention, when the variable capacity supercharger is in operation, when the engine speed is low and the flow rate of the exhaust gas is in the low flow rate range, the link mechanism is operated and the plurality of variable By rotating the nozzle synchronously in the closing direction, the gas flow passage area (throat area) of the exhaust gas supplied to the turbine impeller side is reduced, the flow velocity of the exhaust gas is increased, and the turbine impeller Ensure sufficient work load. On the other hand, when the engine speed is high and the flow rate of the exhaust gas is in the large flow rate range, the plurality of variable nozzles are rotated in synchronization with the opening direction while operating the link mechanism. The gas passage area of the exhaust gas supplied to the impeller side is increased, and a large amount of exhaust gas is supplied to the turbine impeller side. Thus, the turbine impeller can generate the rotational force sufficiently and stably regardless of the flow rate of the exhaust gas (normal operation of the variable displacement supercharger).

When each variable nozzle is rotated in the opening direction to the rotation end on the opening side of the rotation range, the rear edge of each variable nozzle protrudes radially inward with respect to the inner edge of the opposing surface of the second base ring. Therefore, when the above-described new knowledge is applied, the flow rate of the exhaust gas in the large flow rate region is maintained while maintaining sufficient turbine efficiency in the small flow rate region during operation of the variable capacity turbocharger. (A characteristic action of the variable capacity supercharger).

  According to the present invention, the exhaust gas flow rate can be increased in the large flow rate region while maintaining sufficient turbine efficiency in the small flow rate region during the operation of the variable capacity supercharger. Thus, the fuel efficiency of the engine can be sufficiently improved by satisfying both the improvement of the turbine efficiency and the increase of the turbine capacity in the large flow rate range.

FIG. 1 is an enlarged view of an arrow I in FIG. FIG. 2 is an enlarged cross-sectional view taken along the line II-II in FIG. FIG. 3 is an enlarged view of the arrow III in FIG. FIG. 4 is a view showing most of the variable nozzle unit according to the embodiment of the present invention. FIG. 5A is a view showing a nozzle ring in the variable nozzle unit according to the embodiment of the present invention, and FIG. 5B is a cross-sectional view taken along the line VB-VB in FIG. 6A is a view showing a support ring in the variable nozzle unit according to the embodiment of the present invention, and FIG. 6B is a cross-sectional view taken along line VIB-VIB in FIG. 6A. FIG. 7 is a front sectional view of the variable capacity supercharger according to the embodiment of the present invention. FIG. 8 is a diagram for explaining a characteristic part of another embodiment of the present invention, and corresponds to FIG. FIG. 9A is a schematic partial cross-sectional view of a variable capacity supercharger according to a conventional example, and FIG. 9B is a cross-sectional view taken along line IXB-IXB in FIG. 9A. FIG. 10A is a schematic partial cross-sectional view of the variable capacity supercharger according to the invention example, and FIG. 10B is a cross-sectional view taken along line XB-XB in FIG. FIG. 11 is a diagram showing the results of performance tests for the variable capacity supercharger according to the conventional example and the variable capacity supercharger according to the invention example.

Embodiment of the present invention
An embodiment of the present invention will be described with reference to FIGS. As shown in the drawing, “R” is the right direction and “L” is the left direction.

  As shown in FIG. 7, the variable displacement supercharger 1 according to the embodiment of the present invention supercharges (compresses) the air supplied to the engine using the energy of the exhaust gas from the engine (not shown). ) The specific configuration of the variable capacity supercharger 1 is as follows.

  The variable capacity supercharger 1 includes a bearing housing 3, and a radial bearing 5 and a pair of thrust bearings 7 are provided in the bearing housing 3. In addition, a rotor shaft (turbine shaft) 9 extending in the left-right direction is rotatably provided in the plurality of bearings 5, 7. In other words, the rotor shaft 9 is provided in the bearing housing 3. , 7 are rotatably provided.

  A compressor housing 11 is provided on the right side of the bearing housing 3, and a compressor impeller 13 for compressing air using centrifugal force is disposed in the compressor housing 11 (in other words, the rotor shaft 9 Is provided to be rotatable around C. The compressor impeller 13 includes a compressor wheel (compressor disk) 15 integrally connected to the right end of the rotor shaft 9 and a plurality of compressor blades provided on the outer peripheral surface of the compressor wheel 15 at equal intervals in the circumferential direction. 17.

  An air introduction port 19 for introducing air is formed on the inlet side of the compressor impeller 13 in the compressor housing 11 (upstream side in the air flow direction). The air introduction port 19 is an air cleaner that purifies the air. (Not shown) can be connected. Further, an annular diffuser passage 21 that pressurizes compressed air is formed on the outlet side of the compressor impeller 13 between the bearing housing 3 and the compressor housing 11 (downstream side in the air flow direction). Further, a spiral compressor scroll passage 23 is formed inside the compressor housing 11, and the compressor scroll passage 23 communicates with the diffuser passage 21. An air discharge port 25 for discharging compressed air is formed at an appropriate position of the compressor housing 11, and this air discharge port 25 communicates with the compressor scroll passage 23, and Can be connected to an intake manifold (not shown).

  As shown in FIGS. 3 and 7, a turbine housing 27 is provided on the left side of the bearing housing 3, and a rotational force (rotational torque) is generated in the turbine housing 27 using the pressure energy of the exhaust gas. The turbine impeller 29 for generating the engine shaft is provided so as to be rotatable around an axis C (the axis of the turbine impeller 29, in other words, the axis of the rotor shaft 9). The turbine impeller 29 includes a turbine wheel (turbine disk) 31 provided integrally with the left end portion of the rotor shaft 9 and a plurality of turbines provided on the outer peripheral surface of the turbine wheel 31 at equal intervals in the circumferential direction. And a blade 33. Here, tip edges 33 a of the plurality of turbine blades 33 are covered with a shroud wall 27 s of the turbine housing 27.

  A gas introduction port 35 for introducing exhaust gas is formed at an appropriate position of the turbine housing 27, and this gas introduction port 35 can be connected to an exhaust manifold (not shown) of the engine. Further, a spiral turbine scroll passage 37 is formed on the inlet side of the turbine impeller 29 inside the turbine housing 27 (upstream side in the flow direction of the exhaust gas). It communicates with the inlet 35. Furthermore, a gas discharge port 39 for discharging exhaust gas is formed on the outlet side of the turbine impeller 29 in the turbine housing 27 (downstream side in the flow direction of the exhaust gas). It can be connected to an exhaust gas purification device (not shown) for purifying gas.

  An annular heat shield plate 41 that shields heat from the turbine impeller 29 side is provided on the left side surface of the bearing housing 3, and the outer peripheral edge (outer periphery) of the left side surface of the bearing housing 3 and the heat shield plate 41 is provided. An annular urging member 43 such as a disc spring or a wave washer is provided between the two ends.

  The variable displacement turbocharger 1 is equipped with a variable nozzle unit 45 that varies the flow area (throat area) of exhaust gas supplied to the turbine impeller 29 side. Details of the configuration of the variable nozzle unit 45 are as follows. It becomes as follows.

  As shown in FIGS. 1, 3 to 5 (a) and 5 (b), a first nozzle ring 47 as a first base ring is disposed concentrically with the turbine impeller 29 in the turbine housing 27. In the first nozzle ring 47, a plurality of support holes 49 are formed at equal intervals in the circumferential direction. The inner peripheral edge (inner peripheral end) of the first nozzle ring 47 is fitted to the outer peripheral edge (step on the outer peripheral edge) of the heat shield plate 41.

  A plurality of guide claws 51 are integrally formed radially at intervals in the circumferential direction on the outer side in the radial direction of the support hole 49 on the right side surface of the first nozzle ring 47. A guide groove 53 having a U-shaped cross section is provided on the radially outer side. Further, on the inner peripheral edge (inner peripheral surface side) of the right side surface of the first nozzle ring 47, an annular connecting convex portion 55 protruding rightward (one side in the axial direction) is a base portion of the plurality of guide claws 51. Are connected to each other.

  As shown in FIGS. 1 to 4, a plurality of second nozzle rings 57 as second base rings are arranged in the circumferential direction at positions facing the first nozzle ring 47 in the left-right direction (the axial direction). The first nozzle ring 47 is provided integrally and concentrically via (three or more) connecting pins 59. Here, the plurality of connecting pins 59 have a function of setting an interval between the opposing surface (left side surface) 47 f of the first nozzle ring 47 and the opposing surface (right side surface) 57 f of the second nozzle ring 57.

  As shown in FIGS. 1 to 3, a plurality of variable nozzles 61 are arranged between the opposed surface 47 f of the first nozzle ring 47 and the opposed surface 57 f of the second nozzle ring 57 so as to surround the turbine impeller 29. The variable nozzles 61 are arranged in the opening / closing direction (opening direction) around an axis parallel to the axis C of the turbine impeller 29 within a set rotation range (predetermined rotation range). And the closing direction). Further, a nozzle shaft 63 is integrally formed on the right side surface (one side surface in the axial direction) of each variable nozzle 61, and each nozzle shaft 63 is inserted into the corresponding support hole 49 of the first nozzle ring 47. It is rotatably supported. Here, in FIG. 2, the variable nozzle 61 indicated by the solid line is positioned at the opening end of the rotation range, and the variable nozzle 61 indicated by the phantom line is the rotation end on the closing side of the rotation range. Is located. Each variable nozzle 61 has one nozzle shaft 63, but another nozzle shaft (not shown) is integrally formed on the left side surface (the other side surface in the axial direction) of each variable nozzle 61. Each of the different nozzle shafts may be rotatably supported in another support hole (not shown) of the second nozzle ring 57.

  An annular link chamber 65 is defined on the right side of the first nozzle ring 47 (on the side opposite to the facing surface 47f). A link mechanism 67 for rotating the plurality of variable nozzles 61 in the opening / closing direction is disposed in the link chamber 65, and the link mechanism 67 is a nozzle of the plurality of variable nozzles 61. The shaft 63 is linked and connected. The specific configuration of the link mechanism 67 is as follows.

  As shown in FIGS. 1, 3, and 4, the drive ring 69 is inserted into the guide groove 53 of the plurality of guide claws 51 of the first nozzle ring 47 (the axis of the first nozzle ring 47). Center) The guide ring 69 is supported so as to be rotatable in the forward / reverse direction (opening / closing direction) around C, and the drive ring 69 is rotated in the forward / reverse direction by driving of a rotary actuator 71 such as an electric motor or a negative pressure cylinder. To do. Further, the inner periphery of the drive ring 69 is formed with engagement recesses (engagement portions) 73 that are recessed radially outward and the same number as the variable nozzle 61 at equal intervals. Is formed with another engaging recess (another engaging portion) 75 that is recessed outward in the radial direction. Further, a base portion of a synchronous link member (nozzle link member) 77 is integrally connected to the nozzle shaft 63 of each variable nozzle 61, and the distal end portion of each synchronous link member 77 corresponds to a corresponding engagement of the drive ring 69. The engaging recess 73 is engaged. Instead of the drive ring 69 being guided and supported by the guide grooves 53 of the plurality of guide claws 51 of the first nozzle ring 47 so as to be rotatable in the forward and reverse directions, as shown in Patent Literature 2 and Patent Literature 3, The guide ring (not shown) provided on the surface opposite to the facing surface 47f of the one nozzle ring 47 may be guided and supported so as to be rotatable in the forward and reverse directions.

  A drive shaft 79 is provided on the left side portion of the bearing housing 3 via a bush 81 so as to be rotatable around an axis parallel to the axis of the turbine impeller 29, and a right end portion (one end portion) of the drive shaft 79 is provided. ) Is connected to the rotation actuator 71 via the power transmission mechanism 83. Further, the base end portion of the drive link member 85 is integrally connected to the left end portion (the other end portion) of the drive shaft 79, and the tip end portion of the drive link member 85 is connected to another engagement of the drive ring 69. It is engaged with a mating recess (another engaging portion) 75.

  As shown in FIGS. 1, 3, 4, and 6 (a) and 6 (b), the inner peripheral edge of the support ring 87 is formed on the right side surface of the first nozzle ring 47 (the surface opposite to the facing surface 47 f). The support pins 87 are integrally joined by caulking and joining at right end portions (one end portions) of the plurality of connecting pins 59, and have a larger diameter than the outer diameter of the first nozzle ring 47. A plurality of joining pieces 89 for integrally joining to the right side surface of the first nozzle ring 47 are integrally formed on the inner peripheral surface of the support ring 87 so as to protrude radially inward and at intervals in the circumferential direction. Each joint piece 89 is formed with a through hole 91 through which the left end of the connecting pin 59 is inserted. Further, the outer peripheral edge portion of the support ring 87 is attached to the bearing housing 3 in a state of being sandwiched by cooperation with the turbine housing 27. Here, most of the variable nozzle unit 45 is arranged in the turbine housing 27 by attaching the outer peripheral edge of the support ring 87 to the bearing housing 3.

  Subsequently, the characteristic part of the variable displacement supercharger 1 including the characteristic part of the variable nozzle unit 45 will be described.

An annular housing step 93 serving as an annular housing recess for housing the inner peripheral portion of the second nozzle ring 57 is formed on the inlet side of the turbine impeller 29 inside the turbine housing 27. An annular gap 95 is formed between the outer peripheral surface of the accommodation step portion 93 and the inner peripheral surface of the second nozzle ring 57. In addition, a circumferential groove 97 is formed on the outer peripheral surface of the accommodation step portion 93 of the turbine housing 27, and between the peripheral groove 97 of the accommodation step portion 93 of the turbine housing 27 and the inner peripheral surface of the second nozzle ring 57. Are provided with a plurality of seal rings 99 as seal members for suppressing the leakage of exhaust gas from the left side of the second nozzle ring 57 (opposite side of the opposing surface 57f) to the gap 95. In addition, instead of the annular housing step 93 being formed on the inlet side of the turbine impeller 29 inside the turbine housing 27, an annular housing recess (not shown) for housing the entire second nozzle ring 57 is formed. It doesn't matter if you do.

  The rear edge 61t of each variable nozzle 61 rotates the second nozzle ring 57 when the variable nozzle 61 is rotated in the opening direction to the opening side rotation end side (near the opening side rotation end) of the rotation range. It protrudes radially inward with respect to the inner edge 57fe of the opposing surface 57f. Further, the rear edge 61t of each variable nozzle 61 has an inner peripheral edge 93e of the accommodation step portion 93 of the turbine housing 27 when the variable nozzle 61 is rotated in the opening direction to the rotation end on the opening side of the rotation range. (In other words, it is located radially inward from the outer peripheral edge 27se of the shroud wall 27s of the turbine housing 27). In addition, when each variable nozzle 61 is rotated in the opening direction to the rotation end on the opening side of the rotation range, the rear edge 61t of each variable nozzle 61 is from the inner peripheral edge 93e of the accommodation step portion 93 of the turbine housing 27. May also be located radially outward.

  Then, the effect | action and effect of embodiment of this invention are demonstrated.

  By causing the exhaust gas introduced from the gas introduction port 35 to flow from the inlet side to the outlet side of the turbine impeller 29 via the turbine scroll flow path 37, the rotational energy (rotational torque) is generated using the pressure energy of the exhaust gas. Thus, the rotor shaft 9 and the compressor impeller 13 can be rotated integrally with the turbine impeller 29. Thereby, the air introduced from the air inlet 19 can be compressed and discharged from the air outlet 25 via the diffuser passage 21 and the compressor scroll passage 23, and the air supplied to the engine is supercharged. (Compressed).

  During operation of the variable displacement turbocharger 1, when the engine speed is low and the exhaust gas flow rate is in the low flow rate range, the drive ring 69 is driven in the reverse direction (closed direction) by the rotation actuator 71 being driven. The plurality of variable nozzles 61 are synchronously rotated in the closing direction (reverse direction) while being rotated to swing the plurality of synchronous link members 77 in the reverse direction. Thereby, the flow area (throat area) of the exhaust gas supplied to the turbine impeller 29 side can be reduced, the flow rate of the exhaust gas can be increased, and the work amount of the turbine impeller 29 can be sufficiently ensured. On the other hand, when the engine speed is high and the flow rate of the exhaust gas is in a large flow rate range, the drive ring 69 is rotated in the forward direction (opening direction) by driving the rotation actuator 71, whereby a plurality of synchronization links are provided. While swinging the member 77 in the forward direction, the plurality of variable nozzles 61 are synchronously rotated in the opening direction (forward direction). Thereby, the flow passage area of the exhaust gas supplied to the turbine impeller 29 side is increased, and a large amount of exhaust gas is supplied to the turbine impeller 29 side. Therefore, the rotational force can be generated sufficiently and stably by the turbine impeller 29 regardless of the flow rate of the exhaust gas (normal operation of the variable displacement supercharger 1).

  When each variable nozzle 61 is rotated in the opening direction to the opening end on the opening side of the rotation range, the rear edge 61t of each variable nozzle 61 has a diameter with respect to the inner edge 57fe of the opposing surface 57f of the second nozzle ring 57. When the above-described new knowledge is applied, while the variable displacement turbocharger 1 is in operation, the exhaust gas is exhausted in the large flow rate region while maintaining sufficient turbine efficiency in the small flow rate region. The flow rate of the gas can be increased (a specific action of the variable capacity supercharger 1).

  Therefore, according to the embodiment of the present invention, it is possible to increase the flow rate of the exhaust gas in the large flow rate region while maintaining sufficient turbine efficiency in the small flow rate region during the operation of the variable capacity supercharger 1. Further, it is possible to achieve both high efficiency of the turbine efficiency in the low flow rate range and high capacity of the turbine capacity in the large flow rate range, and sufficiently improve the fuel consumption of the engine (effect of the variable capacity supercharger 1).

[Other Embodiments of the Present Invention]
Another embodiment of the present invention will be described with reference to FIG. As shown in the drawing, “R” is the right direction and “L” is the left direction.

  As shown in FIG. 8, in another embodiment of the present invention, the variable displacement supercharger 1 (see FIG. 7) is equipped with a variable nozzle unit 101 instead of the variable nozzle unit 45 (see FIG. 1). doing. The variable nozzle unit 101 has the same configuration as that of the variable nozzle unit 45, and only the portion different from the variable nozzle unit 45 in the configuration of the variable nozzle unit 101 and the configuration around it will be described. Of the plurality of constituent elements in the variable nozzle unit 101, those corresponding to the constituent elements in the variable nozzle unit 45 are denoted by the same reference numerals in the drawings.

  A second nozzle ring 103 as a second base ring is disposed at a position facing the first nozzle ring 47 in the left-right direction (the axial direction) via a plurality of connecting pins 59 arranged in the circumferential direction. It is provided integrally and concentrically with the ring 47. The second nozzle ring 103 has a cylindrical shroud portion 105 that covers the leading edges 33 a of the plurality of turbine blades 33.

An annular accommodation step portion 107 as an annular accommodation recess for accommodating the shroud portion 105 of the second nozzle ring 103 is formed on the radially outer side of the turbine impeller 29 inside the turbine housing 27. Further, on the outer circumferential surface of the shroud portion 105 of the second nozzle ring 103, peripheral groove 109 is formed, the outer periphery of the housing stepped portion 107 of the circumferential groove 109 of the shroud portion 105 of the second nozzle ring 103 turbine housing 27 Between the surfaces , a plurality of seal rings 111 are provided as seal members that suppress leakage of exhaust gas from the left side of the second nozzle ring 103 (opposite surface side of the facing surface 103f).

  When each variable nozzle 61 is rotated in the opening direction to the opening end on the opening side of the rotation range, the rear edge 61t of each variable nozzle 61 has a diameter relative to the inner edge 103fe of the opposing surface 103f of the second nozzle ring 103. An annular notch (circumferential groove) 113 is formed on the facing surface 103f side of the second nozzle ring 103 so as to protrude inward in the direction.

  Therefore, since the annular notch 113 is formed on the facing surface 103f side of the second nozzle ring 103, the same operation and effect as the above-mentioned unique operation and effect of the variable displacement supercharger 1 can be achieved. .

  In addition, this invention is not restricted to description of the above-mentioned embodiment, For example, it can implement in a various aspect as follows. That is, when each variable nozzle 61 is rotated in the opening direction to the opening end on the opening side of the rotation range, the rear edge 61t of each variable nozzle 61 is opposed to the opposing surface 57f (103f) of the second nozzle ring 57 (103). ) Of the variable nozzle 61 in place of or instead of projecting radially inward relative to the inner edge 57fe (103fe) of the first nozzle ring 47 in the radial direction. You may protrude inward. Further, the scope of rights encompassed by the present invention is not limited to these embodiments.

DESCRIPTION OF SYMBOLS 1 Variable displacement supercharger 3 Bearing housing 9 Rotor shaft 11 Compressor housing 13 Compressor impeller 27 Turbine housing 29 Turbine impeller 33 Turbine blade 33a Tip edge of turbine blade 45 Variable nozzle unit 47 First nozzle ring (first base ring)
47f Opposing surface of first nozzle ring 47fe Inner edge of opposing surface of first nozzle ring 57 Second nozzle ring (second base ring)
57f Opposing surface of the second nozzle ring 57fe Inner edge of the opposing surface of the second nozzle ring 61 Variable nozzle 61t Rear edge of the variable nozzle 67 Link mechanism 93 Accommodating step (accommodating recess) of the turbine housing
93e Inner peripheral edge of turbine housing housing step 95 Clearance 99 Seal ring (seal member)
101 Variable nozzle unit 103 Second nozzle ring (second base ring)
103f Opposing surface 103fe of the second nozzle ring 103fe Inner edge 105 of the second nozzle ring Shroud portion 113 of the second nozzle ring Notch 200 Variable capacity supercharger 300 according to the conventional example Variable capacity supercharger according to the invention example

Claims (2)

A variable capacity supercharger that supercharges air supplied to the engine side using energy of exhaust gas from the engine,
A first base ring disposed within the turbine housing;
A second base ring provided at a position opposite to the first base ring in the axial direction of the turbine impeller;
Between the opposing surface of the first base ring and the opposing surface of the second base ring, it is disposed along the circumferential direction so as to surround the turbine housing, and rotates in the opening / closing direction within a set rotation range. A plurality of possible variable nozzles,
An annular receiving recess for receiving at least an inner peripheral side portion of the second base ring is formed on the inlet side of the turbine impeller inside the turbine housing, and an outer peripheral surface of the receiving recess and the second base of the turbine housing An annular gap is formed between the inner peripheral surface of the ring,
The trailing edge of each variable nozzle is radially inward with respect to the inner edge of the opposing surface of the second base ring when each variable nozzle is rotated in the opening direction to the opening end on the opening side of the rotation range. A variable capacity turbocharger that protrudes.   2. The variable capacity supercharger according to claim 1, further comprising a seal member that suppresses leakage of exhaust gas from the surface opposite to the facing surface of the second base ring to the gap.

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