ROTARY DEVICE

Description

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of International Application No. PCT/JP2024/019381, filed on May 27, 2024, which claims priority to Japanese Patent Application No. 2023-143955 filed on Sep. 5, 2023, the entire contents of which are incorporated herein by reference.

BACKGROUND ART

Technical Field

The present disclosure relates to a rotary device.

A rotary device such as a turbine may include a plurality of vanes that are arranged radially outside an impeller. The plurality of vanes may be fixed to a ring plate. For example, Patent Literature 1 discloses a turbine device including a plurality of guide vanes arranged radially outside a turbine wheel. The guide vanes are fixed to a support ring. The support ring contacts a cylindrical centering surface directed radially inward of a turbine housing.

CITATION LIST

Patent Literature

Patent Literature 1: JP 2022-161035 A

SUMMARY

Technical Problem

For example, a turbine is supplied with high-temperature exhaust gas. The ring plate may undergo thermal deformation due to heat from the exhaust gas. If the ring plate thermally deforms, a gap may be formed between the ring plate and a housing, potentially allowing the exhaust gas to leak through the gap to a back side of the impeller. This leads to a decrease in turbine performance.

The present disclosure aims to provide a rotary device that can reduce gas leakage.

Solution to Problem

A rotary device according to one aspect of the present disclosure includes a shaft, an impeller that is provided at one end of the shaft, a first housing that accommodates the impeller, a second housing that is connected to the first housing and that accommodates a bearing rotatably supporting the shaft, an annular flow path that is formed between the first housing and the second housing and that is positioned radially outside the impeller, a plurality of vanes that are arranged along a circumferential direction in the annular flow path, a ring plate that is arranged between the plurality of vanes and the second housing and that supports the plurality of vanes, the plurality of vanes being fixed to the ring plate, the ring plate including a positioning surface that faces radially inward and that contacts the second housing from a radially outer side, and an elastic body that is arranged between the ring plate and the second housing and that presses the ring plate and the plurality of vanes in an axial direction, the positioning surface being located radially inside the elastic body or being located at the same position as a radially inner end of the elastic body in a radial direction.

The rotary device may include a scroll flow path that is formed in the first housing and that is positioned radially outside the annular flow path, and a radially outer edge of one of the plurality of vanes may be positioned on a line segment connecting a tongue of the scroll flow path and an axis of the impeller when seen in the axial direction.

The ring plate may include one of a protrusion and a groove that engages with the protrusion, and one of the first housing and the second housing may include the other of the protrusion and the groove.

The elastic body may contact the ring plate at a position radially outside of radially inner edges of the plurality of vanes.

Effects

According to the present disclosure, gas leakage can be reduced.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic cross-sectional view of a turbocharger including a turbine according to a first embodiment.

FIG. 2 is a schematic enlarged cross-sectional view of area A in FIG. 1.

FIG. 3 is a schematic cross-sectional view taken along line III-III in FIG. 1.

FIG. 4 is a schematic enlarged cross-sectional view of the turbocharger including a turbine according to a second embodiment.

DESCRIPTION OF EMBODIMENTS

Embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. Specific dimensions, materials, and numerical values described in the embodiments are merely examples for better understanding, and do not limit the present disclosure unless otherwise specified. In this specification and the drawings, duplicate explanations are omitted for elements having substantially the same functions and configurations by assigning the same sign. Furthermore, elements not directly related to the present disclosure are omitted from the figures.

FIG. 1 is a schematic cross-sectional view of a turbocharger 100 including a turbine T1 according to a first embodiment. The turbine T1 according to the present embodiment is applied to the turbocharger 100. In another embodiment, the turbine T1 may be applied to equipment other than the turbocharger 100, or may be a standalone unit. The turbocharger 100 includes a housing 1, a shaft 2, a turbine impeller 3, and a compressor impeller 4.

As described later, the turbine impeller 3 and the compressor impeller 4 rotate integrally with the shaft 2. Accordingly, an axis of the turbine impeller 3 and an axis of the compressor impeller 4 are identical to an axis of the shaft 2. As such, in the present disclosure, an axial direction, a radial direction, and a circumferential direction of the shaft 2, the turbine impeller 3, and the compressor impeller 4 may simply be referred to as the “axial direction,” the “radial direction,” and the “circumferential direction,”respectively, unless otherwise indicated. Furthermore, in the present disclosure, the axes of the shaft 2, the turbine impeller 3, and the compressor impeller 4 may simply be referred to as the “axis” unless otherwise indicated.

The housing 1 includes a bearing housing (second housing) 5, a turbine housing (first housing) 6, and a compressor housing 7. In the axial direction, one end of the bearing housing 5 is connected to the turbine housing 6 by a fastener such as a G-coupling. In the axial direction, the other end of the bearing housing 5 is connected to the compressor housing 7 by a fastener such as bolts.

The bearing housing 5 includes a bearing hole 51. The bearing hole 51 extends in the axial direction in the bearing housing 5. The bearing hole 51 accommodates a bearing B. The bearing B rotatably supports the shaft 2. In the present embodiment, a pair of rolling bearings is used as the bearing B. In another embodiment, other radial bearings, such as a full-floating bearing or a semi-floating bearing, may be used as the bearing B.

The turbine impeller 3 is provided at a first end of the shaft 2 in the axial direction. The turbine impeller 3 rotates integrally with the shaft 2. The turbine housing 6 accommodates the turbine impeller 3 in a rotatable manner.

The compressor impeller 4 is provided at a second end that is opposite to the first end of the shaft 2 in the axial direction. The compressor impeller 4 rotates integrally with the shaft 2. The compressor housing 7 accommodates the compressor impeller 4 in a rotatable manner.

The compressor housing 7 includes an inlet 71 at an end opposite to the bearing housing 5 in the axial direction. The inlet 71 is connected to an air cleaner (not shown).

The bearing housing 5 and the compressor housing 7 includes a diffuser flow path 72 therebetween. The diffuser flow path 72 has an annular shape. The diffuser flow path 72 is positioned radially outside the compressor impeller 4. The diffuser flow path 72 is fluidly connected to the inlet 71 via the compressor impeller 4.

The compressor housing 7 includes a compressor scroll flow path 73. The compressor scroll flow path 73 is positioned radially outside the diffuser flow path 72. The compressor scroll flow path 73 is connected to the diffuser flow path 72. Furthermore, the compressor scroll flow path 73 is fluidly connected to an intake port of an engine (not shown).

As the compressor impeller 4 rotates, air is sucked into the compressor housing 7 through the inlet 71. The air is accelerated and pressurized by centrifugal force while passing through the compressor impeller 4. The air is further pressurized while passing through the diffuser flow path 72 and the compressor scroll flow path 73. The pressurized air flows out from an outlet opening (not shown), and is directed to the intake port of the engine. In the turbocharger 100, a part including the compressor impeller 4 and the compressor housing 7 functions as a centrifugal compressor C.

The turbine housing 6 includes an outlet 61 at an end opposite to the bearing housing 5 in the axial direction. The outlet 61 is connected to an exhaust gas purifier (not shown).

The bearing housing 5 and the turbine housing 6 includes a connecting flow path (annular flow path) 62 therebetween. The connecting flow path 62 has an annular shape. The connecting flow path 62 is positioned radially outside the turbine impeller 3. The connecting flow path 62 is fluidly connected to the outlet 61 via the turbine impeller 3. A plurality of vanes V are arranged in the connecting flow path 62. The plurality of vanes V are arranged along the circumferential direction in an area radially outside the turbine impeller 3. The vanes V will be described in detail later.

The turbine housing 6 includes a turbine scroll flow path 63. The turbine scroll flow path 63 is positioned radially outside the connecting flow path 62. The turbine scroll flow path 63 is connected to the connecting flow path 62. Furthermore, the turbine scroll flow path 63 is fluidly connected to a gas inlet opening (not shown). The gas inlet opening receives exhaust gas discharged from an exhaust manifold of an engine (not shown).

The exhaust gas is directed from the gas inlet opening to the turbine scroll flow path 63, and further directed through the connecting flow path 62 and the turbine impeller 3 to the outlet 61. As the exhaust gas passes through the turbine impeller 3, the turbine impeller 3 is rotated. Rotational force of the turbine impeller 3 is transmitted to the compressor impeller 4 via the shaft 2. As the compressor impeller 4 rotates, air is pressurized as described above. As such, the pressurized air is directed to the intake port of the engine. In the turbocharger 100, a part including the turbine impeller 3 and the turbine housing 6 functions as the turbine T1.

Next, the vanes V will be described.

FIG. 2 is a schematic enlarged cross-sectional view of area A in FIG. 1. The turbine T1 includes a ring plate 52. Furthermore, in the present embodiment, the ring plate 52 includes a first ring plate 53 and a second ring plate 54. The turbine T1 also includes an elastic body 55. The bearing housing 5 includes an accommodation groove 56 for accommodating the first ring plate 53, the second ring plate 54, and the elastic body 55. The accommodation groove 56 has a substantially annular shape.

In the present embodiment, the plurality of vanes V are supported by the first ring plate 53. The first ring plate 53 is arranged between the plurality of vanes V and the bearing housing 5 in the axial direction. In other words, the first ring plate 53 is arranged between the connecting flow path 62 and the bearing housing 5 in the axial direction. The first ring plate 53 defines a part of the connecting flow path 62. The first ring plate 53 has an annular shape around the axis.

The vanes V are fixed to an end face 53a of the first ring plate 53. The end face 53a faces the connecting flow path 62 in the axial direction. In other words, the vanes V do not move or rotate relative to the first ring plate 53. In the present disclosure, the vane V may also be referred to as a fixed vane. For example, the vanes V may be monolithically formed with the first ring plate 53. Alternatively, the vanes V may be formed separately from the first ring plate 53 and connected to the first ring plate 53 by welding, bolts, or the like.

FIG. 3 is a schematic cross-sectional view taken along line III-III in FIG. 1. FIG. 3 shows a cross-sectional view seen in the axial direction. For better understanding, only the turbine housing 6, the first ring plate 53, and the vanes V are shown in FIG. 3. In the present embodiment, the first ring plate 53 includes a protrusion 57. For example, the protrusion 57 protrudes radially outward from an outer peripheral surface 53b of the first ring plate 53. In the present embodiment, the turbine housing 6 includes a groove 64. The protrusion 57 is inserted into the groove 64. The engagement between the protrusion 57 and the groove 64 prevents rotation of the first ring plate 53 relative to the turbine housing 6, and positions the first ring plate 53 and the plurality of vanes V in the circumferential direction. In another embodiment, the turbine housing 6 may include a protrusion, and the first ring plate 53 may include a groove engaging with the protrusion.

The turbine housing 6 includes a tongue 65. In the present disclosure, the “tongue” refers to a circumferential end of a wall that partitions the turbine scroll flow path 63 and the connecting flow path 62 in the radial direction. In the present embodiment, a leading edge (radially outer edge) LE of one of the plurality of vanes V, namely vane Vb, is positioned on a line segment LS connecting the tongue 65 and the axis X. In the present disclosure, the leading edge LE refers to an upstream end of the vane V. In the present embodiment, the remaining vanes V are arranged circumferentially evenly with respect to the vane Vb. In the present disclosure, the vane Vb may also be referred to as a reference vane.

Returning to FIG. 2, the second ring plate 54 is arranged between the first ring plate 53 and the bearing housing 5. In the present disclosure, the second ring plate 54 may also be referred to as a “heat shield plate.” The second ring plate 54 has an annular shape around the axis. For example, the second ring plate 54 is configured to contact an inner peripheral surface 53c and an end surface 53d of the first ring plate 53. The end surface 53d is positioned opposite to the end surface 53a that supports the vanes V.

The bearing housing 5 includes a surface 56a facing radially outward. In the present embodiment, the surface 56a has a cylindrical shape. The surface 56a defines the accommodation groove 56 in the radial direction.

An inner circumferential surface 54a of the second ring plate 54 contacts the surface 56a of the bearing housing 5. Specifically, the inner circumferential surface 54a faces radially inward and contacts the surface 56a from a radially outer side. For example, the inner circumferential surface 54a has a cylindrical shape. For example, the surface 56a is press-fitted into the inner circumferential surface 54a. As such, the plurality of vanes V, the first ring plate 53, and the second ring plate 54 are positioned in the radial direction. In the present disclosure, the inner circumferential surface 54a of the second ring plate 54 may also be referred to as a “positioning surface.”

The elastic body 55 is arranged between the second ring plate 54 and the bearing housing 5 in the axial direction. The elastic body 55 presses the ring plate 52 and the plurality of vanes V toward the turbine housing 6 in the axial direction. In the present embodiment, for example, the elastic body 55 is a disc spring. In another embodiment, the elastic body 55 may be other elastic bodies, such as a plurality of coil springs.

The elastic body 55 contacts the ring plate 52 at a position radially outside of trailing edges (radially inner edges) TE of the plurality of vanes V. Specifically, in the present embodiment, an outer peripheral edge of the elastic body 55 contacts the second ring plate 54. Accordingly, a diameter of the outer peripheral edge of the elastic body 55 is larger than a diameter of a circle passing through the trailing edges TE of the plurality of vanes V. In the present embodiment, an inner peripheral edge of the elastic body 55 contacts the bearing housing 5.

The elastic body 55 is positioned radially outside a contact position between the second ring plate 54 and the bearing housing 5, i.e., radially outside the inner surface 54a of the second ring plate 54 and the surface 56a of the bearing housing 5. In other words, the inner surface (positioning surface) 54a of the second ring plate 54 is positioned radially inside the elastic body 55.

As described above, the exhaust gas from the engine flows through the connecting flow path 62. The ring plate 52 is exposed to the exhaust gas. If the exhaust gas reaches high temperature, the ring plate 52 may undergo thermal deformation. Thermal deformation in the radially outer part is greater than that in the radially inner part. Accordingly, if the positioning of the ring plate 52 is done at its radially outer part, a gap is easily formed between the ring plate 52 and the bearing housing 5 or the turbine housing 6. In this case, the exhaust gas easily leaks from the gap into the accommodation groove 56 and further to a back side of the turbine impeller 3. This leads to a decrease in the performance of the turbine T1.

In contrast, in the turbine T1 of the present embodiment, the positioning of the ring plate 52 is done at its radially inner part, specifically at the inner peripheral surface 54a of the second ring plate 54. Accordingly, a gap is less likely to be formed between the ring plate 52 and the bearing housing 5. In this case, leakage of exhaust gas can be reduced.

The turbine T1 of the present embodiment as described above includes the shaft 2, the turbine impeller 3 that is provided at one end of the shaft 2, the turbine housing 6 that accommodates the turbine impeller 3, the bearing housing 5 that is connected to the turbine housing 6 and that accommodates the bearing B rotatably supporting the shaft 2, the connecting flow path 62 that is formed between the turbine housing 6 and the bearing housing 5 and that is positioned radially outside the turbine impeller 3, the plurality of vanes V that are arranged along the circumferential direction in the connecting flow path 62, the ring plate 52 that is arranged between the plurality of vanes V and the bearing housing 5 and that supports the plurality of vanes V, the plurality of vanes V being fixed to the ring plate 52, the ring plate 52 including the positioning surface 54a facing radially inward and contacting the bearing housing 5 from the radially outer side, and the elastic body 55 that is arranged between the ring plate 52 and the bearing housing 5 and that presses the ring plate 52 and the plurality of vanes V in the axial direction, the positioning surface 54a being located radially inside the elastic body 55. As described above, according to such a configuration, the positioning of the ring plate 52 is done by the positioning surface 54a located radially inside the elastic body 55. As such, a gap is less likely to be formed between the ring plate 52 and the bearing housing 5. As a result, leakage of exhaust gas can be reduced.

Furthermore, the turbine T1 includes the turbine scroll flow path 63 that is formed in the turbine housing 6 and that is positioned radially outside the connecting flow path 62. The leading edge LE of one of the plurality of vanes V, namely vane Vb, is positioned on the line segment LS that connects the tongue 65 of the turbine scroll flow path 63 and the axis X of the turbine impeller 3 when seen in the axial direction.

Furthermore, in the turbine T1, the ring plate 52 includes the protrusion 57 and the turbine housing 6 includes the groove 64 that engages with the protrusion 57. According to such a configuration, rotation of the ring plate 52 is prevented by a simple structure.

Furthermore, in the turbine T1, the elastic body 55 contacts the ring plate 52 at the position radially outside the trailing edges TE of the plurality of vanes V. According to such a configuration, the vanes V are firmly pressed against the turbine housing 6.

Next, another embodiment will be described.

FIG. 4 is a schematic enlarged cross-sectional view of the turbocharger 100 including a turbine T2 according to a second embodiment. The turbine T2 differs from the turbine T1 of the first embodiment in that the ring plate 52 only includes the first ring plate 53 and does not include the second ring plate 54. Furthermore, the accommodation groove 56 is reduced in both the radial direction and the axial direction. Specifically, the surface 56a of the bearing housing 5 is moved radially outward. For other configurations, the turbine T2 may be the same as the turbine T1.

In the present embodiment, the inner peripheral surface 53c of the first ring plate 53 is used for positioning the plurality of vanes V and the first ring plate 53. Specifically, in the present embodiment, the inner peripheral surface 53c of the first ring plate 53 contacts the surface 56a of the bearing housing 5. The inner peripheral surface 53c faces radially inward and contacts the surface 56a from an radially outer side. For example, the inner peripheral surface 53c has a cylindrical shape. For example, the surface 56a is press-fitted into the inner peripheral surface 53c. As such, the plurality of vanes V and the first ring plate 53 are positioned in the radial direction. In the present disclosure, the inner peripheral surface 53c of the first ring plate 53 may also be referred to as the “positioning surface.”

In the present embodiment, the outer peripheral edge of the elastic body 55 contacts the first ring plate 53. In the present embodiment, the inner peripheral edge of the elastic body 55 contacts the bearing housing 5. In the present embodiment, the inner peripheral edge of the elastic body 55 is spaced apart from the surface 56a of the bearing housing 5.

The turbine T2 as described above has effects similar to those of the turbine T1 according to the first embodiment.

Although the embodiments of the present disclosure have been described above with reference to the accompanying drawings, the present disclosure is not limited thereto. It is obvious that a person skilled in the art can conceive of various examples of variations or modifications within the scope of the claims, which are also understood to belong to the technical scope of the present disclosure.

For example, in the above embodiment, the present invention is applied to the vanes (nozzle vanes) V arranged in the connecting flow path 62 of the turbine T1. In another embodiment, the present invention may be applied to diffuser vanes (not shown) arranged in the diffuser flow path 72 of the centrifugal compressor C.

Furthermore, for example, in the above embodiment, the protrusion 57 extends radially outward from the outer peripheral surface 53b of the first ring plate 53. In another embodiment, the protrusion 57 may extend radially inward from the inner peripheral surface of the first ring plate 53 or the second ring plate 54, and the groove 64 may be provided at a corresponding position on the bearing housing 5.

Furthermore, for example, in the above embodiments, the positioning surfaces 54a and 53c are located radially inside the elastic body 55. For example, in the second embodiment of FIG. 4, the inner peripheral edge of the elastic body 55 may contact the surface 56a of the bearing housing 5, and the positioning surface 53c may be located at the same position as the inner peripheral edge of the elastic body 55 in the radial direction.