JP6820161B2 - Variable nozzle vane and variable capacity turbocharger - Google Patents

Description

The present disclosure relates to variable nozzle vanes and variable displacement turbochargers.

The variable capacity turbocharger enhances the supercharging effect by changing the flow velocity and pressure of the exhaust gas to the turbine blades by adjusting the flow of exhaust gas from the scroll flow path in the turbine housing to the turbine rotor with a variable nozzle vane. It is a thing.

In recent years, improvement of the response of the engine in the low speed range has been emphasized due to the tightening of exhaust gas regulations, and it is desired to improve the response of the turbocharger. When the engine is accelerated, the rotation speed of the turbine rotor increases by reducing the opening degree of the variable nozzle vane and increasing the exhaust gas pressure. When the opening degree of the nozzle vane is small, the loss of the leakage flow (hereinafter referred to as the clearance flow) from the clearance between the end face of the nozzle vane and the flow path wall is large and the efficiency is low, so that the increase in the rotation speed becomes slow. It ends up.

On the other hand, if the clearance between the end face of the nozzle vane and the flow path wall is reduced, the efficiency of the turbocharger can be improved, but if the clearance is made too small, the nozzle vane and the flow path wall may come into contact with each other due to thermal deformation. If the nozzle vane and the flow path wall come into contact with each other due to thermal deformation, wear may occur due to the operation of the nozzle vane. It may also affect the operability of the nozzle vanes. Therefore, there is a limit to reducing the clearance between the nozzle vane and the flow path wall.

Patent Document 1 discloses a configuration of a variable nozzle vane for the purpose of suppressing a clearance flow. Both ends of the variable nozzle vane described in Patent Document 1 are formed thicker than the central portion, and recesses are provided on the end faces of both ends. Patent Document 1 describes that the labyrinth sealing effect of the concave portion provided on the end face of the nozzle vane improves the sealing property against the clearance flow.

JP-A-11-229815

As described above, Patent Document 1 describes that a recess is provided on the end face of the variable nozzle vane in order to suppress the clearance flow in the variable nozzle vane. However, as for the specific shape of the recess, only the cross-sectional shape along the blade thickness direction is disclosed, and the overall shape of the recess for effectively suppressing the clearance flow is not disclosed.

The present invention has been made in view of the above-mentioned conventional problems, and an object of the present invention is to provide a variable nozzle vane capable of effectively suppressing a clearance flow and a variable capacity turbocharger including the same. That is.

(1) The variable nozzle vane according to at least one embodiment of the present invention is a variable nozzle vane of a variable displacement turbocharger, and the variable displacement turbocharger includes a turbine rotor and a scroll flow path on the outer peripheral side of the turbine rotor. The exhaust gas flow path forming portion includes an exhaust gas flow path forming portion for forming an exhaust gas flow path for guiding exhaust gas from the scroll flow path to the turbine rotor, and the exhaust gas flow path forming portion is the turbine rotor. The variable nozzle vane includes a one side wall portion provided on one side of the variable nozzle vane and the other side wall portion provided on the other side in the axial direction of the variable nozzle vane, and the variable nozzle vane is rotatably provided in the exhaust gas flow path. A recess is formed on at least one of the one side end surface and the other side end surface, including one side end surface facing the one side wall portion and the other side end surface facing the other side wall portion, along the camber line. The size of the recess in the camber direction is larger than the size of the recess in the camber orthogonal direction orthogonal to the camber direction.

According to the variable nozzle vane described in (1) above, the clearance flowing through the gap between the end face (at least one of one side end face and the other side end face) provided with the recess in the variable nozzle vane and the wall surface facing the end face. A part of the flow becomes a circulating flow (vortex) in the gap, and the flow rate of the clearance flow passing through the gap can be reduced. Therefore, the turbine efficiency can be improved.

Further, since the size of the recess in the camber direction is larger than the size of the recess in the direction orthogonal to the camber, the clearance flow passing through the gap from the pressure surface side to the negative pressure surface side is effectively spread over a wide range along the camber line. It can be suppressed.

(2) In some embodiments, in the variable nozzle vane according to (1) above, the recess extends between the front edge and the trailing edge so as not to reach each of the leading and trailing edges. Exists.

According to the variable nozzle vane described in (2) above, the clearance flow is enhanced by strengthening the action of forming the circulation flow in the gap as compared with the case where the recess is provided so as to reach the front edge or the trailing edge. The flow rate can be effectively reduced.

(3) In some embodiments, in the variable nozzle vane according to (2) above, the distance between the recess and the trailing edge is larger than the spacing between the recess and the front edge.

According to the variable nozzle vane described in (3) above, the effect of suppressing the clearance flow described above can be obtained without excessively reducing the wall thickness on the trailing edge side of the variable nozzle vane. That is, the turbine efficiency can be effectively improved while suppressing the occurrence of damage to the trailing edge side portion of the variable nozzle vane.

(4) In some embodiments, in the variable nozzle vane according to any one of (1) to (3) above, the concave portion increases in width in the camber orthogonal direction toward the trailing edge side. Includes a front edge side portion to be connected to the front edge side portion and a trailing edge side portion in which the width of the recess in the direction orthogonal to the camber decreases toward the trailing edge side.

According to the variable nozzle vane described in (4) above, by appropriately changing the width of the recess in the variable nozzle vane in the camber direction, the effect of suppressing the clearance flow described above while ensuring the wall thickness of the peripheral edge of the recess. Can be obtained. That is, the turbine efficiency can be effectively improved while suppressing the occurrence of damage to the peripheral edge of the recess.

(5) In some embodiments, in the variable nozzle vane according to any one of (1) to (4) above, the recess is provided on the bottom surface and on the pressure surface side with respect to the camber line. The side surface on the pressure surface side and the side surface on the negative pressure surface side provided on the negative pressure surface side with respect to the camber line are included.

According to the variable nozzle vane described in (5) above, a part of the clearance flow flowing through the gap between the end surface and the wall surface provided with the recess in the variable nozzle vane is a part of each of the pressure surface side side surface and the negative pressure surface side side surface. Circulating flows can be formed in the vicinity to effectively reduce the flow rate of the clearance flow.

(6) In some embodiments, in the variable nozzle vane according to (5) above, the pressure surface side surface is curved along the pressure surface, and the negative pressure surface side surface is on the negative pressure surface. It is curved along.

According to the variable nozzle vane described in (6) above, it is possible to obtain the effect of suppressing the clearance flow described above while ensuring the wall thickness of the peripheral edge of the recess in the variable nozzle vane. That is, the turbine efficiency can be effectively improved while suppressing the occurrence of damage to the peripheral edge of the recess.

(7) In some embodiments, in the variable nozzle vane according to (5) or (6) above, the angle between the bottom surface and the side surface on the pressure surface side is 90 degrees or less.

According to the variable nozzle vane described in (7) above, the effect of forming a circulating flow near the pressure surface side side surface is enhanced as compared with the case where the angle formed by the bottom surface and the pressure surface side side surface is larger than 90 degrees. , The flow rate of the clearance flow can be effectively reduced. If the angle is 90 degrees, it is advantageous from the viewpoint of ease of manufacture, and if the angle is less than 90 degrees, it is advantageous from the viewpoint of forming a circulating flow in the vicinity of the side surface on the pressure surface side.

(8) In some embodiments, in the variable nozzle vane according to any one of (5) to (7) above, the angle between the bottom surface and the side surface on the negative pressure surface side is 90 degrees or less.

According to the variable nozzle vane described in (8) above, the effect of forming a circulating flow near the side surface on the negative pressure surface is enhanced as compared with the case where the angle formed by the bottom surface and the side surface on the negative pressure surface side is larger than 90 degrees. , The flow rate of the clearance flow can be effectively reduced. If the angle is 90 degrees, it is advantageous from the viewpoint of ease of manufacture, and if the angle is less than 90 degrees, it is advantageous from the viewpoint of forming a circulating flow in the vicinity of the side surface on the negative pressure surface side.

(9) In some embodiments, in the variable nozzle vane according to (5) or (6) above, the bottom surface has a downward slope from the pressure surface side side surface to the negative pressure surface side side surface.

According to the variable nozzle vane described in (9) above, the clearance flow flowing into the recess of the variable nozzle vane flows toward the negative pressure surface side along the bottom surface having a downward slope, but the height of the side surface on the negative pressure surface side is the pressure surface side. Since it is higher than the height of the side surface, it is difficult for it to flow out smoothly from the recess.

(10) In some embodiments, in the variable nozzle vane according to any one of (1) to (9) above, the recess has a cross section orthogonal to the camber direction, and the blade height of the variable nozzle vane is formed. A cross section in which the ratio D / H of the depth D of the recess to H satisfies 0.1 <D / H <0.2 is included.

According to the variable nozzle vane described in (10) above, the action of forming a circulating flow in the gap can be strengthened, and the flow rate of the clearance flow can be effectively reduced. Thereby, the turbine efficiency can be effectively improved.

(11) In some embodiments, in the variable nozzle vane according to any one of (1) to (10) above, the recess has a cross section orthogonal to the camber direction with respect to the width W of the recess. It includes a cross section in which the ratio D / W of the depth D of the recess satisfies 0.1 <D / W <0.35.

According to the variable nozzle vane described in (11) above, the action of forming a circulating flow in the gap can be strengthened, and the flow rate of the clearance flow can be effectively reduced. Thereby, the turbine efficiency can be effectively improved.

(12) In some embodiments, in the variable nozzle vane according to any one of (1) to (11) above, the variable nozzle vane is one piece on one of the one side wall portion and the other side wall portion. Of the one side wall portion and the other side wall portion, the wall portion that cantileverly supports the variable nozzle vane is referred to as a support wall portion, and the wall portion that does not cantileverly support the variable nozzle vane is referred to as a non-support wall portion. Of the one side end face and the other side end face, the end face facing the support wall portion is referred to as a support wall side end face, and the end face facing the non-support wall portion is referred to as a non-support wall side end face. Has the recess.

In a configuration in which the variable nozzle vane is cantilevered and supported by the support wall portion, the clearance flow of the gap between the wall surface of the non-support wall portion and the end surface of the variable nozzle vane on the non-support wall side tends to be a problem. Therefore, by providing the above-mentioned recess on the non-supporting wall side end face, a part of the clearance flow flowing through the gap between the non-supporting wall side end face and the wall surface of the non-supporting wall portion becomes a circulating flow in the gap. The flow rate of the clearance flow passing through the gap can be reduced. Therefore, the turbine efficiency can be improved.

Further, since the size of the recess in the camber direction is larger than the size of the recess in the direction orthogonal to the camber, the clearance flow passing through the gap from the pressure surface side to the negative pressure surface side is effectively spread over a wide range along the camber line. It can be suppressed.

(13) In some embodiments, in the variable nozzle vane according to (12) above, the end portion of the variable nozzle vane on the non-supporting wall side becomes thicker as it approaches the non-supporting wall side. Includes a tapered portion formed so as to.

According to the variable nozzle vane described in (13) above, as compared with the case where the variable nozzle vane is not provided with the tapered portion, by providing the tapered portion, the end face on the non-supporting wall side and the wall surface of the non-supporting wall portion are formed. The flow path length of the gap can be lengthened. Therefore, the pressure gradient between the pressure surface side and the negative pressure surface side in the gap becomes small, and the flow rate of the clearance flow can be reduced.

(14) In some embodiments, in the variable nozzle vane according to (13) above, the negative pressure surface of the tapered portion is directed in the blade height direction so that the blade thickness increases as it approaches the non-supporting wall portion side. Includes an inclined tapered surface.

According to the variable nozzle vane described in (14) above, the tapered surface of the negative pressure surface of the tapered portion makes it difficult for the flow from the throat portion of the nozzle to be attracted to the wall surface of the non-supporting wall portion. Therefore, as compared with the case where the tapered portion is not provided, the loss due to mixing (collision) between the flow from the throat portion and the clearance flow flowing through the gap can be reduced.

(15) In some embodiments, in the variable nozzle vane according to (14) above, the pressure surface of the tapered portion is formed parallel to the blade height direction.

According to the variable nozzle vane described in (15) above, it is possible to reduce the loss due to the mixing of the flow from the throat portion and the clearance flow while suppressing the deterioration of the aerodynamic performance of the variable nozzle vane.

(16) In some embodiments, in the variable nozzle vanes according to (13) to (14) above, the pressure surface of the tapered portion is such that the blade thickness increases as the pressure surface approaches the non-supporting wall portion side. Includes a tapered surface that is inclined with respect to the height direction.

According to the variable nozzle vane described in (16) above, the flow of the gap between the end surface on the non-supporting wall side and the wall surface of the non-supporting wall portion is compared with the case where the pressure surface of the tapered portion is not provided with the tapered surface. The road length can be lengthened. Therefore, the pressure gradient between the pressure surface side and the negative pressure surface side in the gap becomes small, and the flow rate of the clearance flow can be reduced.

(17) In some embodiments, in the variable nozzle vanes according to (13) to (16) above, the tapered portion is provided on the non-supporting wall side from a position of 80% of the blade height H of the nozzle vanes. Be done.

If the blade thickness is increased over a wide range in the blade height direction, the aerodynamic performance of the variable nozzle vane will be significantly reduced. Therefore, by providing a tapered portion in the range described in (17) above, the deterioration of the aerodynamic performance is suppressed. , The flow rate of the clearance flow can be reduced.

(18) In some embodiments, in the variable nozzle vanes according to (13) to (17) above, the ratio T2 of the maximum blade thickness T2 of the non-support wall side end surface to the maximum blade thickness T1 of the support wall side end surface. / T1 satisfies 1.5 <T2 / T1 <2.5.

According to the variable nozzle vane described in (18) above, the flow path length of the gap between the end surface on the non-supporting wall side and the wall surface of the non-supporting wall portion is significantly expanded as compared with the case where the tapered portion is not provided. Therefore, the pressure gradient between the pressure surface side and the negative pressure surface side in the gap becomes small, and the flow rate of the clearance flow can be effectively reduced.

(19) In some embodiments, in the variable nozzle vanes according to (1) to (18) above, the variable nozzle vanes are variable nozzle vanes of a variable displacement turbocharger for automobiles.

According to the variable nozzle vane described in (19) above, the clearance flow of the variable nozzle vane in the variable displacement turbocharger for automobiles can be effectively suppressed.

(20) The variable displacement turbocharger according to at least one embodiment of the present invention includes a turbine rotor, a scroll flow path forming portion that forms a scroll flow path on the outer peripheral side of the turbine rotor, and the turbine from the scroll flow path. An exhaust gas flow path forming portion for forming an exhaust gas flow path for guiding the exhaust gas to the rotor, and a variable nozzle vane according to any one of (1) to (19) above are provided.

According to the variable capacity turbocharger according to the above (20), since the variable nozzle vane according to any one of the above (1) to (19) is provided, the clearance flow is effectively suppressed and the turbine efficiency is high. Can be realized.

According to at least one embodiment of the present invention, there is provided a variable nozzle vane capable of effectively suppressing a clearance flow and a variable displacement turbocharger including the variable nozzle vane.

It is the schematic sectional drawing along the rotation axis of the variable capacity type turbocharger 100 which concerns on one Embodiment of this invention. It is a perspective view which shows the schematic structure of the variable nozzle vane 2 (2A) which concerns on one Embodiment. It is a perspective view which shows the schematic structure of the variable nozzle vane 2 (2A) which concerns on one Embodiment. It is a figure which shows the schematic cross section of the variable nozzle vane 2 (2A) (the cross section orthogonal to the camber direction along the camber line of the end surface 32 on the non-support wall side). It is a partially enlarged view of the schematic cross section of the variable nozzle vane 2 (2A) (the cross section orthogonal to the camber direction along the camber line of the end face 32 on the non-support wall side). It is a partially enlarged view of the schematic cross section of the variable nozzle vane 2 (2A) (the cross section orthogonal to the camber direction along the camber line of the end face 32 on the non-support wall side). It is a figure which shows the relationship between the ratio D / W of the depth D of the recess 34 with respect to the width W of the recess 34, and the turbine efficiency. FIG. 2 is a perspective view of the variable nozzle vane 2 (2A) in FIG. 2 as viewed from another direction. It is a figure which shows the relationship between the flow FD from a throat part and a clearance flow FE in a variable nozzle vane which is not provided with a taper part. It is a figure which shows the relationship between the flow FD from a throat part and a clearance flow FE in a variable nozzle vane 2 (2A) provided with a tapered part. It is a perspective view which shows the schematic structure of the variable nozzle vane 2 (2B) which concerns on one Embodiment. It is a figure which shows the schematic cross section of the variable nozzle vane 2 (2B). It is a figure which shows the schematic cross section of the variable nozzle vane 2 which concerns on another embodiment.

Hereinafter, some embodiments of the present invention will be described with reference to the accompanying drawings. However, the dimensions, materials, shapes, relative arrangements, etc. of the components described as embodiments or shown in the drawings are not intended to limit the scope of the present invention to this, but are merely explanatory examples. Absent.
For example, expressions that represent relative or absolute arrangements such as "in a certain direction", "along a certain direction", "parallel", "orthogonal", "center", "concentric" or "coaxial" are exact. Not only does it represent such an arrangement, but it also represents a state of relative displacement with tolerances or angles and distances to the extent that the same function can be obtained.
For example, expressions such as "same", "equal", and "homogeneous" that indicate that things are in the same state not only represent exactly the same state, but also have tolerances or differences to the extent that the same function can be obtained. It shall also represent the state of existence.
For example, an expression representing a shape such as a quadrangular shape or a cylindrical shape not only represents a shape such as a quadrangular shape or a cylindrical shape in a geometrically strict sense, but also an uneven portion or chamfering within a range in which the same effect can be obtained. The shape including the part and the like shall also be represented.
On the other hand, the expressions "equipped", "equipped", "equipped", "included", or "have" one component are not exclusive expressions that exclude the existence of other components.

FIG. 1 is a schematic cross-sectional view of the variable displacement turbocharger 100 according to the embodiment of the present invention along the rotation axis. The variable capacity turbocharger 100 is, for example, a turbocharger for automobiles.

As shown in FIG. 1, the variable displacement turbocharger 100 includes a turbine rotor 4, a scroll flow path forming portion 8 that forms a scroll flow path 6 on the outer peripheral side of the turbine rotor 4, and a scroll flow path 6 to a turbine rotor 4 It includes an exhaust gas flow path forming portion 12 for forming an exhaust gas flow path 10 for guiding the exhaust gas to the turbocharger, and a variable nozzle vane 2 provided in the exhaust gas flow path 10.

The scroll flow path forming portion 8 is composed of a turbine housing 14 that houses the turbine rotor 4.

The exhaust gas flow path forming portion 12 is provided in parallel with the support wall portion 16 that cantileverly supports the variable nozzle vane 2 and the support wall portion 16 that faces the support wall portion 16 and does not cantilever support the variable nozzle vane 2. Includes wall portion 18.

The support wall portion 16 is provided on the side opposite to the scroll flow path 6 (bearing housing 20 side) with respect to the variable nozzle vane 2 in the axial direction of the turbine rotor 4, and extends along the radial direction to the outer peripheral side of the turbine rotor 4. It is composed of an annular plate (nozzle mount). The support wall portion 16 is formed with a through hole 22 penetrating in the thickness direction, and rotatably supports the shaft 24 of the variable nozzle vane 2 inserted through the through hole 22. The variable nozzle vane 2 is configured to rotate by transmitting a driving force from an actuator (not shown) to the shaft 24.

The non-support wall portion 18 is provided on the scroll flow path 6 side (opposite side to the bearing housing 20) with respect to the variable nozzle vane 2 in the axial direction of the turbine rotor 4, and extends along the radial direction to the outer peripheral side of the turbine rotor 4. It is composed of existing annular plates (nozzle plates).

Next, the configuration of the variable nozzle vane 2 will be described with reference to FIGS. 2, 3 and 4. 2 and 3 are perspective views showing a schematic configuration of the variable nozzle vane 2 (2A) according to the embodiment. FIG. 4 is a diagram showing a schematic cross section of the variable nozzle vane 2 (2A).

As shown in at least one of FIGS. 2, 3 and 4, the variable nozzle vane 2 has a pressure surface 26 (back surface), a negative pressure surface 28 (ventral surface), and a wall surface 17 (exhaust gas flow path 10) of the support wall portion 16. The support wall side end surface 30 facing the wall surface facing the exhaust gas flow path) and the non-support wall side end surface 32 facing the wall surface 19 (wall surface facing the exhaust gas flow path 10) of the non-support wall portion 18 are included. Further, a recess 34 is formed in the end surface 32 on the non-support wall side.

In such a configuration, as shown in FIG. 5, a part of the clearance flow flowing through the gap C between the non-supporting wall side end surface 32 of the variable nozzle vane 2 and the wall surface 19 of the non-supporting wall portion 18 circulates in the gap C. It becomes a flow (vortex FA to FC), and the flow rate of the clearance flow passing through the gap C can be reduced. Therefore, the turbine efficiency can be improved.

Further, as shown in FIG. 3, the dimension A1 of the recess 34 in the camber direction along the camber line CL of the non-supporting wall side end surface 32 is larger than the dimension A2 of the recess 34 in the camber orthogonal direction orthogonal to the camber direction. Therefore, the clearance flow passing through the gap C from the pressure surface 26 side to the negative pressure surface 28 side can be effectively suppressed over a wide range along the camber line CL.

In one embodiment, as shown in FIGS. 2 and 3, the recess 34 extends between the leading edge LE and the trailing edge TE so as not to reach each of the leading edge LE and the trailing edge TE.

According to such a configuration, as compared with the case where the recess 34 is provided so as to reach the front edge LE or the trailing edge TE, the action of forming the circulation flow in the gap C is strengthened, and the flow rate of the clearance flow is increased. It can be effectively reduced.

In one embodiment, as shown in FIG. 3, the distance d1 between the recess 34 and the trailing edge TE is larger than the spacing d2 between the recess 34 and the front edge LE.

According to such a configuration, the effect of suppressing the clearance flow described above can be obtained without excessively reducing the wall thickness t on the trailing edge TE side of the variable nozzle vane 2. That is, the turbine efficiency can be effectively improved while suppressing the occurrence of damage to the portion of the variable nozzle vane 2 on the trailing edge TE side.

In one embodiment, as shown in FIG. 3, the recess 34 is connected to the front edge side portion 36 and the front edge side portion 36 in which the width W of the recess 34 in the direction orthogonal to the camber increases toward the trailing edge TE side. It includes a trailing edge side portion 38 in which the width W of the recess 34 in the direction orthogonal to the camber decreases toward the edge side.

According to such a configuration, by appropriately changing the width W of the recess 34 in the camber direction, it is possible to obtain the effect of suppressing the clearance flow described above while ensuring the wall thickness d of the peripheral edge portion 40 of the recess 34. .. That is, the turbine efficiency can be effectively improved while suppressing the occurrence of damage to the peripheral edge portion 40 of the recess 34.

In one embodiment, for example, as shown in FIGS. 2 and 4, the recess 34 is provided with respect to the bottom surface 42, the pressure surface side side surface 44 provided on the pressure surface 26 side with respect to the camber line CL, and the camber line CL. Includes a negative pressure surface side side surface 46 provided on the negative pressure surface 28 side.

According to such a configuration, as shown in FIG. 5, a part of the clearance flow flowing through the gap C between the non-supporting wall side end surface 32 and the wall surface 19 of the non-supporting wall portion 18 is negative on the pressure surface side side surface 44. Circulating flows FA and FC can be formed in the vicinity of each of the pressure surface side side surfaces 46, respectively, to effectively reduce the flow rate of the clearance flow.

In one embodiment, for example, as shown in FIG. 2, the pressure surface side side surface 44 is curved along the pressure surface 26, and the negative pressure surface side side surface 46 is curved along the negative pressure surface 28.

According to such a configuration, it is possible to obtain the effect of suppressing the clearance flow described above while ensuring the wall thickness d (see FIG. 3) of the peripheral edge portion 40 of the recess 34. That is, the turbine efficiency can be effectively improved while suppressing the occurrence of damage to the peripheral edge portion 40 of the recess 34.

In one embodiment, for example, as shown in FIG. 6, the angle θp formed by the bottom surface 42 and the pressure surface side side surface 44 is 90 degrees or less.

According to such a configuration, as compared with the case where the angle θp is larger than 90 degrees, the effect of forming the circulating flow FA in the vicinity of the pressure surface side side surface 44 in FIG. 5 is enhanced, and the flow rate of the clearance flow is effectively reduced. can do. If the angle θp is 90 degrees, it is advantageous from the viewpoint of ease of manufacturing, and if the angle θp is less than 90 degrees, it is advantageous from the viewpoint of forming a circulating flow FA in the vicinity of the pressure surface side side surface 44. ..

In one embodiment, for example, as shown in FIG. 6, the angle θs formed by the bottom surface 42 and the negative pressure surface side side surface 46 is 90 degrees or less.

According to such a configuration, as compared with the case where the angle θs is larger than 90 degrees, the effect of forming the circulating flow FC in the vicinity of the negative pressure surface side side surface 46 in FIG. 5 is enhanced, and the flow rate of the clearance flow is effectively reduced. can do. If the angle θs is 90 degrees, it is advantageous from the viewpoint of ease of manufacturing, and if the angle θs is less than 90 degrees, it is advantageous from the viewpoint of forming a circulating flow FC in the vicinity of the negative pressure surface side side surface 46. ..

In one embodiment, for example, as shown in FIG. 4, the recess 34 has a cross section orthogonal to the camber direction, and the ratio D / W of the depth D of the recess 34 to the width W of the recess 34 is 0.1 <D / W. Includes a cross section that satisfies <0.35.

According to such a configuration, the action of forming a circulating flow in the gap C can be strengthened, and the flow rate of the clearance flow can be effectively reduced. Thereby, as shown in FIG. 7, the turbine efficiency can be effectively improved.

In one embodiment, for example, as shown in FIG. 3, the recess 34 has a cross section orthogonal to the camber direction, and the ratio D / H of the depth D of the recess 34 to the blade height H of the variable nozzle vane 2 is 0.1 <. Includes a cross section that satisfies D / H <0.2.

According to such a configuration, the action of forming a circulating flow in the gap C can be strengthened, and the flow rate of the clearance flow can be effectively reduced. Thereby, the turbine efficiency can be effectively improved.

FIG. 8 is a perspective view of the variable nozzle vane 2 (2A) in FIG. 2 as viewed from another direction.
In one embodiment, for example, as shown in FIGS. 4 and 8, the variable nozzle vane 2 (2A) includes a blade thickness constant portion 48 provided along the blade height direction (direction of the rotation axis of the variable nozzle vane 2). It includes a tapered portion 50 provided on the non-supporting wall portion 18 side with respect to the blade thickness constant portion. The tapered portion 50 is provided at the end portion 52 on the non-supporting wall portion 18 side of the variable nozzle vane 2 (2A), and is formed so that the blade thickness T increases as it approaches the non-supporting wall portion 18 side.

According to such a configuration, as compared with the case where the variable nozzle vane is not provided with the tapered portion 50 (see FIG. 9), by providing the tapered portion 50, as shown in FIG. 10, the non-supporting wall side end surface 32 The flow path length Lp of the gap C between the surface and the non-supporting wall portion 18 can be lengthened. Therefore, the pressure gradient between the pressure surface 26 side and the negative pressure surface 28 side in the gap C becomes small, and the flow rate of the clearance flow can be reduced.

In one embodiment, as shown in FIG. 4, the tapered portion 50 is provided on the non-supporting wall portion 18 side of the variable nozzle vane 2 (2A) from the position P1 at 80% of the blade height H. If the blade thickness is increased over a wide range in the blade height direction, the aerodynamic performance of the variable nozzle vane will be significantly reduced. Therefore, by providing the tapered portion 50 in the above range, the clearance flow can be suppressed while suppressing the deterioration of the aerodynamic performance. The flow rate can be reduced.

In one embodiment, as shown in FIGS. 4 and 8, the negative pressure surface 28 of the tapered portion 50 is inclined with respect to the blade height direction so that the blade thickness T increases as it approaches the non-supporting wall portion 18 side. Includes tapered surface 54.

According to this configuration, as shown in FIG. 10, the tapered surface 54 of the negative pressure surface 28 of the tapered portion 50 causes the flow FD from the throat portion (not shown) of the nozzle to the wall surface 19 of the non-supporting wall portion 18. It becomes difficult to be attracted. Therefore, as compared with the case where the tapered portion 50 is not provided (see FIG. 9), the loss due to mixing (collision) between the flow FD and the clearance flow FE flowing through the gap C can be reduced. ..

In one embodiment, as shown in FIGS. 4 and 8, the pressure surface 26 of the tapered portion 50 is formed parallel to the blade height direction from the support wall side end surface 30 to the non-support wall side end surface 32. ..

According to such a configuration, it is possible to reduce the loss due to the mixing (collision) of the flow FD and the clearance flow FE while suppressing the deterioration of the aerodynamic performance of the variable nozzle vane 2 (2A).

FIG. 11 is a perspective view showing a schematic configuration of the variable nozzle vane 2 (2B) according to the embodiment. FIG. 12 is a diagram showing a schematic cross section of the variable nozzle vane 2 (2B). Hereinafter, among the configurations of the variable nozzle vanes 2 (2B), the differences from the configurations of the variable nozzle vanes 2 (2A) will be described.
In one embodiment, as shown in FIGS. 11 and 12, the pressure surface 26 of the tapered portion 50 is inclined with respect to the blade height direction so that the blade thickness T increases as it approaches the non-supporting wall portion 18 side. Includes tapered surface 56.

The present invention is not limited to the above-described embodiment, and includes a modified form of the above-described embodiment and a combination of these embodiments as appropriate.

For example, in one embodiment, as shown in FIG. 13, the bottom surface 42 of the recess 34 may have a downward slope from the pressure surface side side surface 44 to the negative pressure surface side side surface 46. That is, the bottom surface 42 of the recess 34 may be inclined so that the distance d3 of the non-supporting wall portion 18 from the wall surface 19 increases from the pressure surface side side surface 44 toward the negative pressure surface side side surface 46.

Further, for example, in some of the above-described forms, the configuration in which the recess 34 is provided in the non-support wall side end surface 32 is exemplified, but the recess is provided in at least one of the support wall side end surface 30 and the non-support wall side end surface 32. It suffices if it is done. However, in the form in which the variable nozzle vane 2 is cantilevered and supported by the support wall portion 16, the clearance flow of the gap C between the wall surface 19 of the non-support wall portion 18 and the non-support wall side end surface 32 of the variable nozzle vane 2 tends to be a problem. Therefore, it is desirable to provide the recess 34 described above on the end surface 32 on the non-support wall side.

Further, in some of the above-described embodiments, the variable nozzle vane 2 is cantilevered and supported by the support wall portion 16 of the exhaust gas flow path forming portion 12, but the variable nozzle vane is both held by the exhaust gas flow path forming portion. It may be supported. Also in this case, a recess is formed on at least one end surface of the variable nozzle vane, and the dimension of the recess in the camber direction along the camber line is made larger than the dimension of the recess in the camber orthogonal direction orthogonal to the camber direction. Clearance flow can be effectively suppressed.

2 Variable nozzle vane 4 Turbine rotor 6 Scroll flow path 8 Scroll flow path forming part 10 Exhaust gas flow path 12 Exhaust gas flow path forming part 14 Turbine housing 16 Support wall part 17 Wall surface 18 Non-support wall part 19 Wall surface 20 Bearing housing 22 Through hole 24 Shaft 26 Pressure surface 28 Negative pressure surface 30 Support wall side end surface 32 Non-support wall side end surface 34 Recess 36 Front edge side part 38 Edge side part 40 Peripheral part 42 Bottom surface 44 Pressure surface side side surface 46 Negative pressure surface side side surface 48 Blade thickness constant part 50 Tapered part 52 End 54 Tapered surface 56 Tapered surface 100 Variable capacity turbocharger

Claims (17)

It is a variable nozzle vane of a variable capacity turbocharger,
The variable displacement turbocharger has a turbine rotor, a scroll flow path forming portion that forms a scroll flow path on the outer peripheral side of the turbine rotor, and an exhaust gas flow path for guiding exhaust gas from the scroll flow path to the turbine rotor. Equipped with an exhaust gas flow path forming part to be formed
The exhaust gas flow path forming portion includes one side wall portion provided on one side of the variable nozzle vane and the other side wall portion provided on the other side in the axial direction of the turbine rotor.
The variable nozzle vane is provided in the exhaust gas flow path and includes one side end surface facing the one side wall portion and the other side end surface facing the other side wall portion.
A clearance flow that flows through at least one of the one side end surface and the other side end surface in a gap between the one side wall portion and the one side end surface, or a gap between the other side wall portion and the other side end surface. A recess is formed to circulate a part
The size of the recess in the camber direction along the camber line is larger than the size of the recess in the camber orthogonal direction orthogonal to the camber direction.
The clearance flow flows in and out from the opening provided in the upper part of the recess, and the one-side end surface and the other-side end surface of the recess are provided so as to prevent the inflow and outflow of the clearance flow.
The variable nozzle vane is cantilevered and supported by either one of the one side wall portion and the other side wall portion.
Of the one side wall portion and the other side wall portion, the wall portion that cantileverly supports the variable nozzle vane is referred to as a support wall portion, and the wall portion that does not cantileverly support the variable nozzle vane is referred to as a non-support wall portion.
Of the one-sided end face and the other-side end face, the end face facing the support wall portion is referred to as a support wall side end face, and the end face facing the non-support wall portion is referred to as a non-support wall side end face.
The non-supporting wall side end face has the recess.
The end of the variable nozzle vane on the non-supporting wall side includes a tapered portion formed so that the blade thickness increases as the blade approaches the non-supporting wall side.
The negative pressure surface of the tapered portion includes a tapered surface inclined with respect to the blade height direction so that the blade thickness increases as the blade approaches the non-supporting wall portion side.
The pressure surface of the tapered portion is a variable nozzle vane formed parallel to the blade height direction. The variable nozzle vane according to claim 1, wherein the recess extends between the front edge and the trailing edge so as not to reach each of the leading edge and the trailing edge. The variable nozzle vane according to claim 2, wherein the distance between the concave portion and the trailing edge is larger than the distance between the concave portion and the front edge. The recess is connected to a front edge side portion in which the width of the recess in the direction orthogonal to the camber increases toward the trailing edge side, and the recess is connected to the front edge side portion and the width of the recess in the direction orthogonal to the camber decreases toward the trailing edge side. The variable nozzle vane according to any one of claims 1 to 3, which includes a trailing edge side portion. 1. The recess includes a bottom surface, a pressure surface side surface provided on the pressure surface side with respect to the camber line, and a negative pressure surface side surface provided on the negative pressure surface side with respect to the camber line. 4. The variable nozzle vane according to any one of 4 to 4. The variable nozzle vane according to claim 5, wherein the pressure surface side surface is curved along the pressure surface, and the negative pressure surface side surface is curved along the negative pressure surface. The variable nozzle vane according to claim 5 or 6, wherein the angle between the bottom surface and the side surface on the pressure surface side is 90 degrees or less. The variable nozzle vane according to any one of claims 5 to 7, wherein the angle formed by the bottom surface and the side surface on the negative pressure surface side is 90 degrees or less. The angle between the bottom surface and the side surface on the pressure surface side is less than 90 degrees.
The variable nozzle vane according to claim 8, wherein the angle between the bottom surface and the side surface on the negative pressure surface side is less than 90 degrees. The variable nozzle vane according to claim 5 or 6, wherein the bottom surface has a downward slope from the side surface on the pressure surface side toward the side surface on the negative pressure surface side. The recess includes a cross section orthogonal to the camber direction in which the ratio D / H of the depth D of the recess to the blade height H of the variable nozzle vane satisfies 0.1 <D / H <0.2. , The variable nozzle vane according to any one of claims 1 to 10. The recess comprises a cross section orthogonal to the camber direction in which the ratio D / W of the depth D of the recess to the width W of the recess satisfies 0.1 <D / W <0.35. The variable nozzle vane according to any one of 1 to 11. The variable nozzle vane according to any one of claims 1 to 12 , wherein the tapered portion is provided on the non-supporting wall side from a position of 80% of the blade height H of the variable nozzle vanes. Any of claims 1 to 13 , wherein the ratio T2 / T1 of the maximum blade thickness T2 of the non-support wall side end surface to the maximum blade thickness T1 of the support wall side end surface satisfies 1.5 <T2 / T1 <2.5. The variable nozzle vane according to item 1. The variable nozzle vane according to any one of claims 1 to 14 , wherein the variable nozzle vane is a variable nozzle vane of a variable capacity turbocharger for automobiles. It is a variable nozzle vane of a variable capacity turbocharger,
The variable displacement turbocharger has a turbine rotor, a scroll flow path forming portion that forms a scroll flow path on the outer peripheral side of the turbine rotor, and an exhaust gas flow path for guiding exhaust gas from the scroll flow path to the turbine rotor. Equipped with an exhaust gas flow path forming part to be formed
The exhaust gas flow path forming portion includes one side wall portion provided on one side of the variable nozzle vane and the other side wall portion provided on the other side in the axial direction of the turbine rotor.
The variable nozzle vane is provided in the exhaust gas flow path and includes one side end surface facing the one side wall portion and the other side end surface facing the other side wall portion.
A recess is formed in at least one of the one end surface and the other end surface.
The size of the recess in the camber direction along the camber line is larger than the size of the recess in the camber orthogonal direction orthogonal to the camber direction.
The bottom surface of the recess is not formed with an opening of a passage for communicating the inside and the outside of the recess.
The variable nozzle vane is cantilevered and supported by either one of the one side wall portion and the other side wall portion.
Of the one side wall portion and the other side wall portion, the wall portion that cantileverly supports the variable nozzle vane is referred to as a support wall portion, and the wall portion that does not cantileverly support the variable nozzle vane is referred to as a non-support wall portion.
Of the one-sided end face and the other-side end face, the end face facing the support wall portion is referred to as a support wall side end face, and the end face facing the non-support wall portion is referred to as a non-support wall side end face.
The non-supporting wall side end face has the recess.
The end of the variable nozzle vane on the non-supporting wall side includes a tapered portion formed so that the blade thickness increases as the blade approaches the non-supporting wall side.
The negative pressure surface of the tapered portion includes a tapered surface inclined with respect to the blade height direction so that the blade thickness increases as the blade approaches the non-supporting wall portion side.
The pressure surface of the tapered portion was formed parallel to the blade height direction.
Variable nozzle vane. A turbine rotor, a scroll flow path forming portion that forms a scroll flow path on the outer peripheral side of the turbine rotor, and an exhaust gas flow path forming portion that forms an exhaust gas flow path for guiding exhaust gas from the scroll flow path to the turbine rotor. , A variable displacement turbocharger comprising the variable nozzle vane according to any one of claims 1 to 16 .

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