WO2025229725A1 - Turbine and turbo device - Google Patents

Abstract

This turbine comprises: a turbine wheel; a turbine housing that rotatably accommodates the turbine wheel and defines an annular nozzle flow path on an outer peripheral side of the turbine wheel; a plurality of long nozzle vanes that are provided offset in a circumferential direction so as not to overlap in a radial direction in the nozzle flow path; and a short nozzle vane that is provided between two long nozzle vanes which are adjacent to each other in the circumferential direction among the plurality of long nozzle vanes, and in which the length of a straight line connecting a front edge and a rear edge of the short nozzle vane is shorter than that of the long nozzle vane. The short nozzle vane is provided on a front-edge circumscribed circle that passes through the front edge of each of the two long nozzle vanes which are adjacent to each other in the circumferential direction.

Description

Turbines and turbo equipment

The present disclosure relates to a turbine and a turbo device including the turbine.

Patent Document 1 discloses a turbine equipped with low solidity nozzle vanes, in which the trailing edge inscribed circumference of each nozzle vane located upstream of the turbine wheel is made longer than the chord length of the nozzle vane, in order to achieve high turbine efficiency in the face of engine exhaust pulsation.

Japanese Patent Application Laid-Open No. 2018-123802

In the low solidity nozzle vanes described in Patent Document 1, the nozzle vane blades are short, so there is a risk that they may not be able to fully perform one of their functions, which is to change the direction of upstream flow. For this reason, it is necessary to have the fluid flow into the nozzle flow passage at an angle similar to the inlet angle of the turbine wheel. In this case, it is necessary to design a scroll flow passage that increases the circumferential component of the flow compared to turbines with normal nozzle vanes, but there is a risk that losses will increase because the scroll cross-sectional area needs to be smaller.

In light of the above circumstances, at least one embodiment of the present disclosure aims to provide a turbine that can achieve high turbine efficiency in response to engine exhaust pulsation, and a turbo device equipped with such a turbine.

A turbine according to at least one embodiment of the present disclosure comprises:
A turbine wheel;
a turbine housing configured to rotatably accommodate the turbine wheel and defining an annular nozzle flow path on an outer circumferential side of the turbine wheel;
a plurality of long nozzle vanes provided in the nozzle flow passage so as to be offset in a circumferential direction so as not to overlap in a radial direction;
at least one short nozzle vane is provided between two of the plurality of long nozzle vanes that are adjacent in the circumferential direction, and the length of a straight line connecting a leading edge and a trailing edge of the short nozzle vane is shorter than that of the long nozzle vane,
The at least one short nozzle vane is
The nozzle vanes are provided on a leading edge circumscribing circle passing through the leading edges of the two circumferentially adjacent long nozzle vanes.

A turbo device according to at least one embodiment of the present disclosure includes:
The turbine is provided.

At least one embodiment of the present disclosure provides a turbine that can achieve high turbine efficiency in response to engine exhaust pulsations, and a turbo device equipped with the turbine.

1 is a schematic cross-sectional view of a turbocharger including a turbine according to an embodiment of the present disclosure; 1 is a schematic diagram illustrating a turbine according to an embodiment of the present disclosure viewed from one axial side; 1 is a schematic diagram illustrating a turbine according to an embodiment of the present disclosure viewed from one axial side; 1 is a schematic diagram illustrating a turbine according to an embodiment of the present disclosure viewed from one axial side; 1 is a schematic diagram illustrating a turbine according to an embodiment of the present disclosure viewed from one axial side; 1 is a schematic diagram illustrating a turbine according to an embodiment of the present disclosure viewed from one axial side; 1 is a schematic cross-sectional view of a turbine according to an embodiment of the present disclosure, taken along the circumferential direction in the vicinity of a short blade nozzle vane. FIG.

Several embodiments of the present disclosure will be described below 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 disclosure and are merely illustrative examples.

(Turbines, turbo devices)
Fig. 1 is a schematic cross-sectional view of a turbocharger 10 including a turbine 1 according to one embodiment of the present disclosure. Figs. 2 to 6 are each a front view of the turbine 1 according to one embodiment of the present disclosure, viewed along the axial direction. The symbol N in Figs. 2 to 6 indicates the rotation direction of a turbine wheel 2. A turbocharger 10 (turbo device) according to some embodiments includes a radial turbine 1 (turbine), as shown in Fig. 1. As shown in Fig. 1, the radial turbine 1 includes a turbine wheel 2 that rotates about an axis RA, a turbine housing 3 configured to rotatably house the turbine wheel 2, and a plurality of elongated nozzle vanes 4.

Hereinafter, the direction in which the axis RA of the turbine wheel 2 extends is defined as the axial direction of the turbine wheel 2 (turbine 1), the direction perpendicular to the axis RA is defined as the radial direction of the turbine wheel 2 (turbine 1), and the circumferential direction around the axis RA is defined as the circumferential direction of the turbine wheel 2 (turbine 1). Hereinafter, the axial direction, radial direction, and circumferential direction of the turbine wheel 2 (turbine 1) may be simply referred to as the axial direction, radial direction, and circumferential direction.

The turbine housing 3 defines an annular nozzle flow path 31 on the outer periphery of the turbine wheel 2. As shown in Figures 2 to 6, each of the multiple long nozzle vanes 4 has a leading edge 41, a trailing edge 42, a pressure surface 43, and a suction surface 44. Each of the pressure surface 43 and suction surface 44 is a blade surface extending from the leading edge 41 to the trailing edge 42. The pressure surface 43 is located upstream of the suction surface 44 in the direction of rotation N. As shown in Figures 2 to 6, each of the multiple long nozzle vanes 4 is offset circumferentially in the nozzle flow path 31 so as not to overlap radially. In other words, a circumferential gap is formed between the leading edge 41 of one of the long nozzle vanes 4 and the trailing edge 42 of the other of two circumferentially adjacent long nozzle vanes 4.

In the embodiment shown in FIG. 1, the turbine wheel 2 includes a truncated cone-shaped turbine hub 21 provided on one axial side of the rotating shaft 11, and a plurality of turbine rotor blades 22 provided at intervals in the circumferential direction on the peripheral surface of the turbine hub 21. The rotating shaft 11 is rotatably supported by journal bearings 13A and 13B housed in a bearing housing 12. A truncated cone-shaped compressor hub 141 is provided on the other axial side of the rotating shaft 11. A plurality of compressor rotor blades 142 are provided at intervals in the circumferential direction on the peripheral surface of the compressor hub 141. The compressor impeller 14 is composed of the compressor hub 141 and the compressor rotor blades 142. The compressor impeller 14 is housed in a compressor housing 15 in a state where it can rotate about the axis RA.

In the embodiment shown in FIG. 1, in addition to the nozzle flow path 31 described above, the interior of the turbine housing 3 is formed with a scroll flow path 32 through which exhaust gas introduced from outside the turbine housing 3 flows, and an outlet flow path 33 for directing the exhaust gas that has driven the turbine wheel 2 to the outside of the turbine housing 3. The scroll flow path 32 is a spiral flow path formed on the outer periphery of the nozzle flow path 31. The outlet flow path 33 is a tubular flow path extending along the axial direction. The exhaust gas that has flowed through the scroll flow path 32 flows radially inward through the nozzle flow path 31 and flows into the turbine wheel 2, causing it to rotate. The exhaust gas that has driven the turbine wheel 2 to rotate then flows axially through the outlet flow path 33 and is discharged to the outside of the turbine housing 3.

(long nozzle vane)
In the embodiment shown in FIG. 1 , the above-described plurality of long nozzle vanes 4 are configured as variable nozzle vanes rotatably attached to the turbine housing 3. The variable nozzle vanes are rotatably supported between a nozzle mount 6 and a nozzle plate 7, which are arranged facing each other with a nozzle flow path 31 in between. The variable nozzle vanes are configured to rotate when a driving force from an actuator 16 is transmitted via a variable mechanism 17. The nozzle mount 6 and the nozzle plate 7 are each annular plate-shaped members having an opening in the center, and have flow path surfaces that form the nozzle flow path 31. The nozzle mount 6 and the nozzle plate 7 are connected by a nozzle support 8. In the embodiment shown in FIG. 1 , the turbine 1 includes the nozzle mount 6, the nozzle plate 7, and the nozzle support 8.

The multiple long nozzle vanes 4 described above may also be configured as fixed nozzle vanes that are non-rotatably attached to the turbine housing 3. Fixed nozzle vanes are fixed non-rotatably to at least one of the nozzle mount 6 and the flow path surface of the nozzle plate 7 that define the nozzle flow path 31. When the long nozzle vanes 4 are configured as fixed nozzle vanes, there is no need for components for rotating the long nozzle vanes 4, such as the actuator 16 and variable mechanism 17 shown in Figure 1. Furthermore, when a flow path surface that forms the nozzle flow path 31 is provided in the turbine housing 3, the nozzle plate 7 is not required.

2, each of the multiple long nozzle vanes 4 of the turbine 1 according to some embodiments is a low solidity nozzle vane configured to satisfy the relationship Lvf < Lcf/Nvf, where Lvf is the length of the straight line connecting the leading edge 41 and trailing edge 42 of the long nozzle vane 4 (vane length), Lcf is the perimeter of the trailing edge inscribed circle C1 passing through the trailing edge 42 of each of the multiple long nozzle vanes 4, and Nvf is the number of multiple long nozzle vanes 4. In other words, adjacent long nozzle vanes 4 of each of the multiple long nozzle vanes 4 do not overlap in the circumferential direction, and an inter-long nozzle vane throat is formed between the leading edge 41 of one nozzle vane 4 of a pair of adjacent nozzle vanes 4A, 4B and the trailing edge 42 of the nozzle vane 4 on the other side. Here, the inter-long nozzle vane throat refers to the portion forming the smallest width between adjacent long nozzle vanes in the circumferential direction. The throat th refers to the part that forms the smallest width between adjacent nozzle vanes in the circumferential direction, without distinguishing between long nozzle vanes 4 and short nozzle vanes 5.

If the long nozzle vane 4 is a variable nozzle vane, the above-mentioned condition Lvf < Lcf/Nvf is satisfied when the variable nozzle vane is fully closed.

(Short nozzle vane)
As shown in Figures 2 to 6, the turbine 1 according to some embodiments further includes at least one short nozzle vane 5 provided between two circumferentially adjacent long nozzle vanes 4A, 4B among the plurality of long nozzle vanes 4 described above. As shown in Figures 2 to 6, the short nozzle vane 5 has a leading edge 51, a trailing edge 52, a pressure surface 53, and a suction surface 54. Each of the pressure surface 53 and the suction surface 54 is a blade surface extending from the leading edge 51 to the trailing edge 52. The pressure surface 53 is located upstream of the suction surface 54 in the direction of rotation N. In the short nozzle vane 5, the length of the straight line connecting the leading edge 51 and the trailing edge 52 (chord length Lvs, see Figure 2) is shorter than the chord length of the long nozzle vane 4.

The above-mentioned short nozzle vane 5 is located on a leading edge circumscribing circle C2 that passes through the leading edges 41 of the two circumferentially adjacent long nozzle vanes 4A, 4B. Because the short nozzle vane 5 has a shorter chord length than the long nozzle vane 4, the trailing edge 52 is located radially outward of the trailing edge inscribing circle C1.

At least one short nozzle vane 5, located between two circumferentially adjacent long nozzle vanes 4A, 4B, has a throat formed between its pressure surface 53 and the trailing edge 42 of the long nozzle vane 4A located upstream in the rotational direction N.

In the illustrated embodiment, the above-mentioned short nozzle vanes 5 are configured as fixed nozzle vanes that are non-rotatably attached to the turbine housing 3. For example, the fixed nozzle vanes are fixed non-rotatably to at least one of the flow path surfaces of the nozzle mount 6 and the nozzle plate 7 that define the nozzle flow path 31. Furthermore, if the turbine housing 3 has a flow path surface that defines the nozzle flow path 31, the fixed nozzle vanes may be fixed non-rotatably to the flow path surface of the turbine housing 3.

Upstream of the nozzle flow path 31 where the short nozzle vanes 5 are provided, the short nozzle vanes 5 can guide the flow of fluid flowing in from the scroll flow path 32. Furthermore, downstream of the nozzle flow path 31 where the short nozzle vanes 5 are not provided, the blade-to-blade distance between the two nozzle vanes (long nozzle vanes 4A, 4B) can be increased, allowing the long nozzle vanes 4 to function as low solidity nozzle vanes.

Specifically, downstream of the nozzle flow path 31, the pulsating flow can vary the outlet outlet angle of the nozzle flow path 31. As a result, when the flow rate fluctuations due to pulsation are high, the flow becomes more radial. Furthermore, when the flow rate fluctuations due to pulsation are low, the circumferential component increases, reducing the fluctuation in the relative inflow angle to the turbine wheel 2. Therefore, the above-mentioned turbine 1 can achieve high turbine efficiency in response to engine exhaust pulsation.

As shown in FIG. 2, the turbine 1 according to some embodiments is configured so that the leading edge 51 of at least one short nozzle vane 5 described above is located at the same radial position as the leading edge 41 of the long nozzle vane 4. In other words, the leading edge 51 of the short nozzle vane 5 is located on the leading edge circumscribing circle C2. In this case, the short nozzle vane 5 can guide the fluid flow upstream of the nozzle flow path 31.

As shown in FIG. 3, the turbine 1 according to some embodiments is configured so that the leading edge 51 of at least one of the above-mentioned short nozzle vanes 5 is located radially outward of the leading edge 41 of the long nozzle vane 4. In this case, the short nozzle vane 5 can guide the fluid flow upstream of the nozzle flow path 31. Furthermore, by positioning the leading edge 51 of the short nozzle vane 5 radially outward of the leading edge 41 of the long nozzle vane 4, the chord length of the short nozzle vane 5 can be increased, allowing the short nozzle vane 5 to guide the fluid flow over a relatively wide area of the nozzle flow path 31.

As shown in FIG. 2, the turbine 1 according to some embodiments is configured to satisfy the relationship 2 × (Nvs/Nvf) × Lvs < Lcf/Nvf, where Lvs is the length (chord length) of the straight line connecting the leading edge 51 and trailing edge 52 of the short nozzle vane 5, Lcf is the perimeter of the trailing edge inscribed circle C1 passing through the trailing edge 42 of each of the multiple long nozzle vanes 4, Nvs is the number of at least one short nozzle vane 5, and Nvf is the number of multiple long nozzle vanes 4.

When the above conditional expression 2 x (Nvs/Nvf) x Lvs < Lcf/Nvf is satisfied, the chord length Lvs of the short nozzle vanes 5 becomes optimal, and the short nozzle vanes 5 can optimally perform their functions of guiding the fluid flow and varying the outlet outlet angle of the nozzle flow path 31 using pulsating flow. This allows for higher turbine efficiency in response to engine exhaust pulsations. Note that when the long nozzle vanes 4 are variable nozzle vanes, the above conditional expression 2 x (Nvs/Nvf) x Lvs < Lcf/Nvf is satisfied when the variable nozzle vanes are fully closed.

In some embodiments of the turbine 1, as shown in Figures 2 to 5, the at least one short nozzle vane 5 includes a plurality of short nozzle vanes 5 spaced apart in the circumferential direction. The plurality of short nozzle vanes 5 are each provided between two circumferentially adjacent long nozzle vanes 4A, 4B. In this case, the structure of the turbine 1 can be simplified compared to when a plurality of short nozzle vanes 5 are provided between two circumferentially adjacent long nozzle vanes 4A, 4B.

In some embodiments of the turbine 1, as shown in FIG. 6, the at least one short nozzle vane 5 includes a plurality of short nozzle vanes 5 spaced apart in the circumferential direction. The plurality of short nozzle vanes 5 includes two or more (two in the illustrated example) short nozzle vanes 5 provided between each pair of circumferentially adjacent long nozzle vanes 4A, 4B. In this case, by increasing the number of short nozzle vanes 5 provided between each pair of circumferentially adjacent long nozzle vanes 4A, 4B, the fluid flow can be guided by the plurality of short nozzle vanes 5 upstream of the nozzle flow path 31.

In some embodiments of the turbine 1, as shown in FIG. 2, the at least one short nozzle vane 5 described above is provided at a circumferential position including the midpoint CP of the arc between the leading edges 41, 41 of the leading edge circumscribing circle C2 that passes through the leading edges 41 of two circumferentially adjacent long nozzle vanes 4A, 4B. By providing the short nozzle vane 5 at a circumferential position that includes the midpoint CP, the length of the throat formed between the pressure surface 53 of the short nozzle vane 5 and the trailing edge 42 of the long nozzle vane 4A located upstream in the rotational direction N can be made appropriate.

4 and 5, for reference, short nozzle vanes 5 arranged at circumferential positions including the middle CP are indicated by two-dot chain lines. In some embodiments of the turbine 1, as shown in FIG. 4, at least one of the above-mentioned short nozzle vanes 5 is arranged upstream of the above-mentioned middle CP in the rotational direction N of the turbine wheel 2. The pressure surface 53 of the short nozzle vane 5 has a larger angle change than the suction surface 54, and therefore has a greater effect on the outlet flow angle. By arranging the short nozzle vane 5 upstream of the middle CP in the rotational direction N, it is possible to increase the fluctuation in the outlet outlet flow angle of the nozzle flow path 31 due to the pulsating flow.

In some embodiments of the turbine 1, as shown in FIG. 5, at least one of the short nozzle vanes 5 described above is located downstream of the intermediate CP described above in the direction of rotation N of the turbine wheel 2. The pressure surface 53 of the short nozzle vane 5 has a greater angle change than the suction surface 54, and therefore has a greater effect on the outlet angle. By locating the short nozzle vane 5 downstream of the intermediate CP in the direction of rotation N, it is possible to reduce fluctuations in the outlet outlet angle of the nozzle flow path 31 due to pulsating flow.

Figure 7 is a schematic cross-sectional view along the circumferential direction near a short-bladed nozzle vane 5 of a turbine 1 according to an embodiment of the present disclosure. In some embodiments of the turbine 1, as shown in Figure 7, the nozzle mount 6 (plate-shaped member) described above includes an annular plate portion 61 having a flow path surface 62 facing the nozzle flow path 31 and a back surface 63 spaced apart from the nozzle flow path 31 in the axial direction of the turbine wheel 2 relative to the flow path surface 62. The short nozzle vane 5 described above includes at least a blade surface forming portion 55 that forms the blade surfaces (pressure surface 53, suction surface 54) facing the nozzle flow path 31, and an insertion portion 56 that passes through a through-hole 64 formed in the flow path surface 62 of the nozzle mount 6, and is formed by plastically processing a metal plate.

In the illustrated embodiment, the blade surface forming portion 55 has a side portion that forms the pressure surface 53, a side portion that forms the negative pressure surface 54, and a side portion 551 that connects these side portions and abuts the flow path surface of the nozzle plate 7. The side portion 551 extends in a direction that intersects with the axial direction (orthogonal in the illustrated example).

By forming the short nozzle vanes 5 by plastically processing metal plates, the manufacturing costs of the short nozzle vanes 5 can be reduced. Furthermore, the short nozzle vanes 5 include insertion portions 56 that pass through through holes 64 formed in the flow path surface 62 of the nozzle mount 6 (plate-shaped member), making them easy to attach to the nozzle mount 6.

In the illustrated embodiment, the short nozzle vane 5 further includes a biasing portion 57 configured to bias the nozzle mount 6 (plate-shaped member) toward the nozzle flow path 31. The biasing portion 57 is formed by plastically processing a metal plate. By supporting the plate-shaped member 6 with the short nozzle vane 5 including the biasing portion 57 that allows axial deformation, structural errors in the nozzle flow path 31 that occur due to changes in the operating state of the turbomachine 10 can be tolerated, making it possible to reduce the clearance of the long nozzle vane 4 that tends to occur on the turbine housing 3 side of the nozzle flow path 31.

In the illustrated embodiment, the above-mentioned biasing portion 57 comprises a first radial extending portion 571, an axial extending portion 572, and a second radial extending portion 573. The first radial extending portion 571 extends radially outward and is adapted to abut at least a portion thereof against the back surface 63 of the nozzle mount 6 (plate-shaped member). The axial extending portion 572 has one end connected to the radially outer end of the first radial extending portion 571 and extends away from the axial nozzle flow path 31. The second radial extending portion 573 extends radially inward from the other end of the axial extending portion 572 and is adapted to abut at least a portion thereof against the opposing surface 121 of another member (in the illustrated example, the bearing housing 12) that faces the back surface 63 of the nozzle mount 6 (plate-shaped member) across an axial gap. In this case, the biasing portion 57 has a simple structure that can be easily formed by plastic processing a metal plate, and is capable of exerting a biasing force. Note that in some other embodiments, the plate-like member described above may be a nozzle plate 7.

In some embodiments of the turbine 1, each of the plurality of long nozzle vanes 4 described above is a variable nozzle vane that is rotatably mounted relative to the turbine housing 3. When the long nozzle vanes 4 are configured as variable nozzle vanes, the turbine 1 can exhibit high turbine efficiency in response to engine exhaust pulsations.

In some embodiments of the turbine 1, each of the plurality of long nozzle vanes 4 described above is a fixed nozzle vane that is non-rotatable relative to the turbine housing 3. When the long nozzle vanes 4 are configured as fixed nozzle vanes, the turbine 1 can achieve high turbine efficiency in response to engine exhaust pulsations.

As shown in Figure 1, a turbo device (turbocharger 10) according to some embodiments includes the turbine 1 described above. Because the turbine 1 can exhibit high turbine efficiency in response to engine exhaust pulsation, the efficiency of the turbo device (turbocharger 10) can be improved.

In this specification, expressions expressing relative or absolute arrangement such as "in a certain direction,""along a certain direction,""parallel,""orthogonal,""center,""concentric," or "coaxial" not only express such an arrangement strictly, but also express a state in which there is a relative displacement with a tolerance or an angle or distance to the extent that the same function is obtained.
For example, expressions such as "identical,""equal," and "homogeneous" that indicate that something is in an equal state not only indicate a state of strict equality, but also indicate a state in which there is a tolerance or a difference to the extent that the same function is obtained.
Furthermore, in this specification, expressions representing shapes such as a rectangular shape or a cylindrical shape not only represent rectangular shapes or cylindrical shapes in the strict geometric sense, but also represent shapes including uneven portions, chamfered portions, etc., to the extent that the same effect can be obtained.
Furthermore, in this specification, the expressions "comprise,""include," or "have" a component are not exclusive expressions that exclude the presence of other components.

The present disclosure is not limited to the above-described embodiments, but also includes modifications to the above-described embodiments and appropriate combinations of these embodiments.

The contents described in the above-mentioned embodiments can be understood, for example, as follows:

1) A turbine (1) according to at least one embodiment of the present disclosure,
A turbine wheel (2);
a turbine housing (3) configured to rotatably accommodate the turbine wheel (2) and defining an annular nozzle flow path (31) on the outer periphery of the turbine wheel (2);
a plurality of long nozzle vanes (4) provided in the nozzle flow path (31) so as to be offset in the circumferential direction so as not to overlap in the radial direction;
and at least one short nozzle vane (5) that is provided between two of the long nozzle vanes (4A, 4B) adjacent to each other in the circumferential direction and has a length of a straight line (53) connecting a leading edge (51) and a trailing edge (52) that is shorter than that of the long nozzle vane (4),
The at least one short nozzle vane (5)
The nozzle vanes are provided on a leading edge circumscribing circle (C2) passing through the leading edges (41) of the two elongated nozzle vanes (4A, 4B) adjacent to each other in the circumferential direction.

With the configuration of 1) above, the short nozzle vanes (5) can guide the flow of fluid. Furthermore, since the short nozzle vanes (5) are not provided downstream of the nozzle flow path, the blade-to-blade distance between the two nozzle vanes (long nozzle vanes 4A, 4B) can be increased, and the outlet outflow angle of the nozzle flow path (31) can be varied by the pulsating flow. As a result, when the flow rate fluctuations due to pulsation are high, the flow becomes more radial. Furthermore, when the flow rate fluctuations due to pulsation are low, the circumferential component increases, reducing the variation in the relative inflow angle to the turbine wheel (2). Therefore, with the configuration of 1) above, high turbine efficiency can be achieved in response to engine exhaust pulsation.

2) In some embodiments, the turbine (1) according to 1) above,
The at least one short nozzle vane (5) is configured such that the leading edge (51) is located at the same position in the radial direction as the leading edge (41) of the long nozzle vane (4).

The configuration described in 2) above allows the short nozzle vane (5) to guide the fluid flow upstream of the nozzle flow path (31).

3) In some embodiments, the turbine (1) according to 1) above,
The at least one short nozzle vane (5) is configured such that the leading edge (51) is positioned radially outward of the leading edge (41) of the long nozzle vane (4).

The configuration of 3) above allows the short nozzle vanes (5) to guide the fluid flow upstream of the nozzle flow path (31). Furthermore, by positioning the leading edge (51) of the short nozzle vanes (5) radially outward of the leading edge (41) of the long nozzle vanes (4), the chord length of the short nozzle vanes (5) can be increased, allowing the short nozzle vanes (5) to guide the fluid flow over a relatively wide area in the nozzle flow path (31).

4) In some embodiments, the turbine (1) according to any one of 1) to 3) above,
The length of the straight line connecting the leading edge (51) and the trailing edge (52) of the short nozzle vane (5) is Lvs,
The perimeter of a trailing edge inscribed circle passing through the trailing edge (42) of each of the plurality of long nozzle vanes (4) is Lcf,
The number of the at least one short nozzle vane (5) is Nvs,
When the number of the plurality of long nozzle vanes (4) is defined as Nvf,
It is configured to satisfy 2×(Nvs/Nvf)×Lvs<Lcf/Nvf.

According to the configuration of 4) above, when the above conditional expression 2 × (Nvs/Nvf) × Lvs < Lcf/Nvf is satisfied, the chord length (Lvs) of the short nozzle vanes (5) becomes optimal, and the short nozzle vanes (5) can optimally perform their functions of guiding the fluid flow and varying the outlet outflow angle of the nozzle flow path (31) using pulsating flow. This allows for higher turbine efficiency in response to engine exhaust pulsation.

5) In some embodiments, the turbine (1) according to any one of 1) to 4) above,
The at least one short nozzle vane (5) includes a plurality of short nozzle vanes (5) spaced apart in the circumferential direction,
The plurality of short nozzle vanes (5) are provided such that one short nozzle vane (5) is provided between each of the two long nozzle vanes (4A, 4B) adjacent to each other in the circumferential direction.

The configuration of 5) above simplifies the structure of the turbine (1) compared to when multiple short nozzle vanes (5) are provided between two circumferentially adjacent long nozzle vanes (4A, 4B).

6) In some embodiments, the turbine (1) according to any one of 1) to 4) above,
The at least one short nozzle vane (5) includes a plurality of short nozzle vanes (5) spaced apart in the circumferential direction,
The plurality of short nozzle vanes (5) are provided such that two or more short nozzle vanes (5) are provided between each of the two long nozzle vanes (4A, 4B) adjacent to each other in the circumferential direction.

According to the configuration of 6) above, by increasing the number of short nozzle vanes (5) provided between two circumferentially adjacent long nozzle vanes (4A, 4B), the flow of fluid can be guided by multiple short nozzle vanes (5) upstream of the nozzle flow path (31).

7) In some embodiments, the turbine (1) according to any one of 1) to 6) above,
The at least one short nozzle vane (5)
The nozzle vanes are provided at a circumferential position including the midpoint (CP) of the arc between the leading edges (41) of a leading edge circumscribing circle (C2) that passes through the leading edges (41) of the two circumferentially adjacent long nozzle vanes (4A, 4B).

According to the configuration of 7) above, by arranging the short nozzle vane (5) at a circumferential position including the middle (CP), the length of the throat (th) formed between the pressure surface (53) of the short nozzle vane (5) and the trailing edge (42) of the long nozzle vane (4A) located upstream in the direction of rotation (N) can be made appropriate.

8) In some embodiments, the turbine (1) according to any one of 1) to 6) above,
The at least one short nozzle vane (5)
The nozzle vanes are provided upstream of the middle of the arc between the leading edges (41) of the leading edge circumscribing circle that passes through the leading edges (41) of the two circumferentially adjacent long nozzle vanes (4A, 4B) in the direction of rotation of the turbine wheel (2).

In the configuration of 8) above, the pressure surface (53) of the short nozzle vane (5) has a larger angle change than the suction surface (54), and therefore has a greater effect on the outlet angle. By locating the short nozzle vane (5) upstream of the middle point (CP) in the direction of rotation (N), it is possible to increase the fluctuation in the outlet outlet angle of the nozzle flow path 31 due to the pulsating flow.

9) In some embodiments, the turbine (1) according to any one of 1) to 6) above,
The at least one short nozzle vane (5)
The nozzle vanes are provided downstream in the direction of rotation of the turbine wheel (2) from the midpoint (CP) of the arc between the leading edges (41) of the leading edge circumscribing circle that passes through the leading edges (41) of the two circumferentially adjacent long nozzle vanes (4A, 4B).

In the configuration of 9) above, the pressure surface (53) of the short nozzle vane (5) has a larger angle change than the suction surface (54), and therefore has a greater effect on the outlet angle. By locating the short nozzle vane (5) downstream of the middle point (CP) in the direction of rotation (N), fluctuations in the outlet outlet angle of the nozzle flow path 31 due to pulsating flow can be reduced.

10) In some embodiments, the turbine (1) according to any one of 1) to 9) above,
a plate-like member (nozzle mount 6) including an annular plate portion (61) having a flow path surface (62) facing the nozzle flow path (31) and a back surface (63) spaced apart from the nozzle flow path (31) in the axial direction of the turbine wheel (2) relative to the flow path surface (62);
The at least one short nozzle vane (5)
a blade surface forming portion (55) that forms blade surfaces (pressure surface 53, negative pressure surface 54) facing the nozzle flow path (31);
and an insertion portion (56) that passes through a through-hole (64) formed in the flow path surface (62) of the plate-like member (6),
It was formed by plastically processing a metal plate.

According to the configuration of 10) above, the short nozzle vane (5) is formed by plastically processing a metal plate, thereby reducing the manufacturing cost of the short nozzle vane (5). Furthermore, the short nozzle vane (5) includes an insertion portion (56) that passes through the through hole (64) formed in the flow path surface (62) of the plate-shaped member (6), making it easy to attach to the plate-shaped member (6).

11) In some embodiments, the turbine (1) according to 10) above,
The at least one short nozzle vane (5)
The apparatus further includes a biasing portion (57) configured to bias the plate-like member (6) toward the nozzle flow path (31).

In the configuration of 11) above, the plate-like member (6) is supported by the short nozzle vane (5) including the biasing portion (57) that allows deformation in the axial direction, thereby allowing for structural errors in the nozzle flow path (31) that occur due to changes in the operating state of the turbomachine (10), thereby making it possible to reduce the clearance of the long nozzle vane (4) that tends to occur on the turbine housing (3) side of the nozzle flow path (31).

12) In some embodiments, the turbine (1) according to 11) above,
The biasing portion (57)
a first radially extending portion (571) extending outward in the radial direction and having at least a portion abutting against the back surface (63) of the plate-shaped member (6);
an axially extending portion (572) having one end connected to the radially outer end of the first radially extending portion (571) and extending away from the nozzle flow path (31) in the axial direction;
and a second radially extending portion (573) that extends radially inward from the other end of the axially extending portion (572) and at least a portion of which abuts against an opposing surface (121) of another member (bearing housing 12) that faces the back surface (63) of the plate-shaped member (6) across an axial gap.

According to the configuration of 12) above, the biasing portion (57) has a simple structure that can be easily formed by plastically processing a metal plate, and is capable of exerting a biasing force.

13) In some embodiments, the turbine (1) according to any one of 1) to 12) above,
Each of the plurality of long nozzle vanes (4) is a variable nozzle vane that is rotatably provided with respect to the turbine housing (3).

According to the configuration of 13) above, when the long nozzle vane (4) is configured as a variable nozzle vane, the turbine (1) can exhibit high turbine efficiency in response to engine exhaust pulsation.

14) In some embodiments, the turbine (1) according to any one of 1) to 12) above,
Each of the plurality of long nozzle vanes (4) is a fixed nozzle vane that is non-rotatable relative to the turbine housing (3).

According to the configuration of 14) above, when the long nozzle vanes (4) are configured as fixed nozzle vanes, the turbine (1) can exhibit high turbine efficiency in response to engine exhaust pulsations.

15) A turbo device (10) according to at least one embodiment of the present disclosure,
The turbine (1) is provided as described in any one of 1) to 14) above.

The configuration of 15) above allows the turbine (1) to exhibit high turbine efficiency in response to engine exhaust pulsations, thereby improving the efficiency of the turbo device (10).

REFERENCE SIGNS LIST 1 turbine 2 turbine wheel 3 turbine housing 4 long nozzle vane 5 short nozzle vane 6 nozzle mount 7 nozzle plate 8 nozzle support 10 turbocharger 11 rotating shaft 12 bearing housing 13A, 13B journal bearing 14 compressor impeller 15 compressor housing 31 nozzle flow passage 32 scroll flow passage 33 outlet flow passage 41, 51 leading edge 42, 52 trailing edge

Claims (15)

A turbine wheel;
a turbine housing configured to rotatably accommodate the turbine wheel and defining an annular nozzle flow path on an outer circumferential side of the turbine wheel;
a plurality of long nozzle vanes provided in the nozzle flow passage so as to be offset in a circumferential direction so as not to overlap in a radial direction;
at least one short nozzle vane is provided between two of the plurality of long nozzle vanes that are adjacent in the circumferential direction, and the length of a straight line connecting a leading edge and a trailing edge of the short nozzle vane is shorter than that of the long nozzle vane,
The at least one short nozzle vane is
provided on a leading edge circumscribing circle passing through the leading edges of each of the two circumferentially adjacent long nozzle vanes,
Turbine. the at least one short nozzle vane is configured such that the leading edge is located at the same position in the radial direction as the leading edge of the long nozzle vane;
The turbine of claim 1 . the at least one short nozzle vane is configured such that the leading edge is positioned radially outward of the leading edge of the long nozzle vane;
The turbine of claim 1 . The length of the straight line connecting the leading edge and the trailing edge of the short nozzle vane is Lvs,
The perimeter of a trailing edge inscribed circle passing through the trailing edge of each of the plurality of long nozzle vanes is Lcf,
Nvs is the number of the at least one short nozzle vane,
When the number of the plurality of long nozzle vanes is defined as Nvf,
Configured to satisfy 2×(Nvs/Nvf)×Lvs<Lcf/Nvf,
A turbine according to any one of claims 1 to 3. the at least one short nozzle vane includes a plurality of short nozzle vanes spaced apart in the circumferential direction,
The plurality of short nozzle vanes are each provided between two of the long nozzle vanes adjacent to each other in the circumferential direction,
A turbine according to any one of claims 1 to 3. the at least one short nozzle vane includes a plurality of short nozzle vanes spaced apart in the circumferential direction,
The plurality of short nozzle vanes are provided such that two or more short nozzle vanes are provided between each of the two long nozzle vanes adjacent to each other in the circumferential direction, and the same number of short nozzle vanes are provided between each of the two long nozzle vanes adjacent to each other in the circumferential direction.
A turbine according to any one of claims 1 to 3. The at least one short nozzle vane is
a leading edge circumscribing circle passing through the leading edges of the two circumferentially adjacent elongated nozzle vanes, the leading edge circumscribing circle being provided at a circumferential position including a midpoint of an arc between the leading edges of the two circumferentially adjacent elongated nozzle vanes;
A turbine according to any one of claims 1 to 3. The at least one short nozzle vane is
the nozzle vanes are provided upstream in a rotation direction of the turbine wheel from a midpoint of an arc between the leading edges of a leading edge circumscribing circle that passes through the leading edges of the two circumferentially adjacent long nozzle vanes,
A turbine according to any one of claims 1 to 3. The at least one short nozzle vane is
a nozzle vane circumferentially adjacent to each other in the direction of rotation of the turbine wheel, the nozzle vane circumferentially adjacent to each other in the direction of rotation of the turbine wheel being disposed downstream of a middle point of an arc between the leading edges of a leading edge circumscribed circle passing through the leading edges of the two long nozzle vanes adjacent to each other in the direction of rotation of the turbine wheel;
A turbine according to any one of claims 1 to 3. a plate-like member including an annular plate portion having a flow path surface facing the nozzle flow path and a back surface spaced apart from the nozzle flow path in the axial direction of the turbine wheel relative to the flow path surface,
The at least one short nozzle vane is
a blade surface forming portion that forms a blade surface facing the nozzle flow path;
an insertion portion that passes through a through hole formed in the flow path surface of the plate-like member,
Formed by plastic processing of metal plate,
A turbine according to any one of claims 1 to 3. The at least one short nozzle vane is
further including a biasing portion configured to bias the plate-shaped member toward the nozzle flow path,
The turbine of claim 10. The biasing portion is
a first radially extending portion that extends outward in the radial direction and has at least a portion that abuts against the back surface of the plate-like member;
an axially extending portion having one end connected to the radially outer end of the first radially extending portion and extending away from the nozzle flow path in the axial direction;
a second radially extending portion that extends radially inward from the other end of the axially extending portion and at least a portion of which abuts against an opposing surface of another member that faces the back surface of the plate-like member across an axial gap,
The turbine of claim 11 . Each of the plurality of long nozzle vanes is a variable nozzle vane that is rotatably provided with respect to the turbine housing.
A turbine according to any one of claims 1 to 3. each of the plurality of long nozzle vanes is a fixed nozzle vane that is non-rotatable with respect to the turbine housing;
A turbine according to any one of claims 1 to 3. A turbo device equipped with the turbine described in any one of claims 1 to 3.