CN112696261A

CN112696261A - Turbocharger structure and middle shell thereof

Info

Publication number: CN112696261A
Application number: CN202110023905.0A
Authority: CN
Inventors: 陈伟; 陆瑶; 崔伟
Original assignee: Wuxi Cummins Turbo Technologies Co Ltd
Current assignee: Wuxi Cummins Turbo Technologies Co Ltd
Priority date: 2021-01-08
Filing date: 2021-01-08
Publication date: 2021-04-23

Abstract

The invention provides a turbocharger structure and a middle shell thereof, wherein the turbocharger structure comprises: the turbine shaft bearing comprises an intermediate shell, a turbine shaft arranged in the intermediate shell and a bearing arranged between the intermediate shell and the turbine shaft, wherein the intermediate shell is provided with a turbine end shaft hole used for accommodating the turbine shaft at a turbine end, a bearing seat used for accommodating the bearing at the inner part, and a cavity is arranged between the turbine end shaft hole and the bearing seat, and the cavity forms a dome area at one side close to the turbine end shaft hole; the middle shell is further provided with an annular groove structure formed by extending towards the inside of the middle shell along the vortex end shaft hole in the dome area, and a gap is formed between the groove structure and the bearing seat. In the application, the groove structure is arranged on the middle shell of the turbocharger, so that the temperature of the vortex end sealing system and the temperature of the bearing system can be balanced, and the durability and the sealing performance of the turbocharger can be enhanced with low cost.

Description

Turbocharger structure and middle shell thereof

Technical Field

The invention belongs to the field of turbomachinery of internal combustion engines, and particularly relates to a turbocharger structure and a middle shell thereof.

Background

This section is intended to provide a background or context to the embodiments of the invention that are recited in the claims. The description herein is not admitted to be prior art by inclusion in this section.

Turbochargers are used to extract energy from the exhaust gas of an engine exhaust manifold and provide the energy to the engine intake manifold, increasing the output of an internal combustion engine.

The conventional turbocharger comprises a turbine shell, a turbine wheel, a turbine shaft, an intermediate shell (bearing shell), a compressor wheel, a compressor shell and other parts, wherein a bearing system (a turbine end bearing and a pressure end bearing) for rotatably supporting the turbine shaft is arranged inside the intermediate shell of the turbocharger, and a sealing system for preventing oil and gas from leaking between the turbine and the intermediate shell is formed at a turbine end of the turbine compressor.

Since the turbine shell is directly connected to the engine exhaust manifold, high temperatures are transmitted from the turbine end to the entire turbocharger. Based on this, when the temperature near the bearing system and the vortex end sealing system of the turbocharger exceeds the acceptable limit value, the bearing system and the vortex end sealing system can be failed, and the durability and the sealing performance of the turbocharger are affected.

Disclosure of Invention

In view of the problems in the prior art, a turbocharger structure and an intermediate housing thereof are provided, by which the above problems can be solved.

The present invention provides the following.

In a first aspect, a turbocharger arrangement is provided, comprising: the turbine shaft is arranged in the middle shell, and the bearing is arranged between the middle shell and the turbine shaft; the middle shell is provided with a turbine end shaft hole for accommodating a turbine shaft at the turbine end, a bearing seat for accommodating a bearing is arranged in the middle shell, a cavity is arranged between the turbine end shaft hole and the bearing seat, and a dome area is formed at one side of the cavity close to the turbine end shaft hole; the middle shell is further provided with an annular groove structure formed by extending towards the inside of the middle shell along the vortex end shaft hole in the dome area, and a gap is formed between the groove structure and the bearing seat.

According to an embodiment of the application, the groove structure and/or the inner side surface of the turbine-end shaft hole and the outer side surface of the turbine shaft are provided with a labyrinth structure which is matched with each other.

According to an embodiment of the application, one or more turbine end seal ring grooves on the turbine shaft and the seal rings mounted on the turbine end seal ring grooves are covered by a groove structure of the intermediate shell.

According to an embodiment of the present application, one or more scroll end seal ring grooves on the turbine shaft and a seal ring mounted on the scroll end seal ring grooves are covered by an inside surface of a scroll end shaft hole of the middle casing.

According to an embodiment of the application, an oil slinging groove structure is formed on the turbine shaft and is located in a gap between the groove structure and the bearing seat.

According to an embodiment of the present application, a radial thickness S of the groove structure ranges from ═ H to ═ H, and an axial thickness H of the groove structure ranges from ═ H to ·; wherein h is the minimum axial groove width of the turbine end sealing ring groove on the turbine shaft.

According to an embodiment of the application, the cavity in the intermediate shell extends from the dome area in a direction away from the vortex end.

In a second aspect, there is provided an intermediate housing of a turbocharger, the intermediate housing being provided at a turbine end thereof with a turbine end shaft hole for accommodating a turbine shaft, a bearing housing provided in an interior thereof for accommodating a bearing, and a cavity provided between the turbine end shaft hole and the bearing housing, the cavity forming a dome region at a side close to the turbine end shaft hole; the middle shell is further provided with an annular groove structure formed by extending along the vortex end shaft hole in the direction of the bearing seat in the dome area, and a gap is formed between the groove structure and the bearing seat.

According to an embodiment of the application, the inner side surface of the groove structure and/or the turbine-end shaft hole is further provided with a sealing structure for forming a labyrinth sealing structure cooperating with another sealing structure provided on the outer side surface of the turbine shaft.

According to an embodiment of the application, the inner side surface of the groove structure of the intermediate casing is formed with a stepped hole such that the groove structure is configured for covering one or more turbine end seal ring grooves on the turbine shaft and a seal ring mounted on the turbine end seal ring grooves.

According to an embodiment of the present application, an inner side surface of the scroll end shaft hole of the intermediate shell is formed with a stepped hole such that the scroll end shaft hole is configured to cover one or more scroll end seal ring grooves on the turbine shaft and a seal ring mounted on the scroll end seal ring grooves.

According to an embodiment of the present application, a radial thickness S of the groove structure is 0.5 to 1.5H, and an axial thickness H of the groove structure is 0.4 to 1.0H; wherein h is the minimum axial groove width of the turbine end sealing ring groove on the turbine shaft.

The embodiment of the application adopts at least one technical scheme which can achieve the following beneficial effects: in this embodiment, due to the addition of the groove structure, more material is used for bearing heat near the vortex end sealing system, and thus the heat is reduced to be transferred to the vortex end sealing system. And, because the lubricant flowing out of the vortex end bearing flows along the dome area, the contact area between the lubricant and the dome area is increased by introducing the groove structure, the heat transferred to the dome area by the vortex end is favorably taken away by the flowing lubricant, and the temperature of a vortex end sealing system is effectively reduced. Meanwhile, a certain gap is reserved between the groove structure of the middle shell and the bearing seat, so that the high temperature of the vortex end is difficult to be directly transmitted to the bearing seat, and the temperature of the bearing system cannot be obviously increased.

It should be understood that the above description is only an overview of the technical solutions of the present invention, so as to clearly understand the technical means of the present invention, and thus can be implemented according to the content of the description. In order to make the aforementioned and other objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below.

Drawings

The advantages and benefits described herein, as well as other advantages and benefits, will be apparent to those of ordinary skill in the art upon reading the following detailed description of the exemplary embodiments. The drawings are only for purposes of illustrating exemplary embodiments and are not to be construed as limiting the invention. Also, like reference numerals are used to refer to like elements throughout. In the drawings:

FIG. 1 is a cross-sectional view of an exemplary conventional turbocharger;

FIG. 2 is an exemplary cross-sectional view of a turbocharger according to an embodiment of the present invention;

FIG. 3 is an enlarged partial view of the scroll area A of the turbocharger shown in FIG. 2;

FIG. 4 is an exemplary cross-sectional view of a turbocharger center housing according to an embodiment of the present invention.

In the drawings, the same or corresponding reference numerals indicate the same or corresponding parts.

Detailed Description

Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be embodied in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

In the description of the embodiments of the present application, it is to be understood that terms such as "including" or "having" are intended to indicate the presence of the features, numbers, steps, actions, components, parts, or combinations thereof disclosed in the specification, and are not intended to preclude the presence or addition of one or more other features, numbers, steps, actions, components, parts, or combinations thereof.

Unless otherwise stated, "/" indicates an OR meaning, e.g., A/B may indicate A or B; "and/or" herein is merely an association describing an associated object, and means that there may be three relationships, e.g., a and/or B, which may mean: a exists alone, A and B exist simultaneously, and B exists alone.

The terms "first", "second", etc. are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first," "second," etc. may explicitly or implicitly include one or more of that feature. In the description of the embodiments of the present application, "a plurality" means two or more unless otherwise specified.

Fig. 1 shows an example of a conventional turbocharger. A conventional turbocharger includes a turbine housing, a turbine wheel, a turbine shaft, an intermediate housing (bearing housing), a compressor wheel, and a compressor housing. Wherein the turbine housing is coupled to an engine exhaust manifold such that engine exhaust gas passes through the turbine wheel to rotate the turbine shaft. The turbine shaft may be a shaft assembly comprising multiple components that may be rotatably supported by a bearing system (a turbine end bearing and a pressure end bearing) disposed inside the intermediate casing such that rotation of the turbine wheel causes rotation of the compressor wheel. Compressor in this application, the compressor wheel delivers compressed gas to the engine intake manifold. Thus, the turbocharger achieves extraction of energy from the exhaust gas of the engine exhaust manifold and supply of energy to the engine intake manifold, improving the output of the internal combustion engine.

In a turbo compressor, a turbine end sealing system is generally formed by a turbine end portion of an intermediate casing, a turbine shaft, a seal ring and the like, and helps prevent lubricant from flowing into a turbine wheel and oil-gas leakage between the turbine wheel and the intermediate casing.

Turbochargers typically operate at high temperatures. Since engine exhaust gas is high temperature gas and the turbine housing is directly connected to the engine exhaust manifold, high temperature is transmitted to the entire turbocharger through the turbine housing. It is understood that bearing systems can cause failure problems such as carbon build-up, wear, etc. when the temperature is too high. The sealing ring of the vortex end sealing system also has certain requirements on temperature, and the sealing ring fails due to overhigh temperature, so that the dynamic sealing function cannot be exerted. Therefore, if the temperature in the vicinity of the bearing system and the scroll seal system of the turbocharger exceeds the acceptable limit, failure of the bearing system and the scroll seal system may occur, thereby affecting the durability and sealing performance of the turbocharger.

The heat energy transferred to the entire turbocharger at the turbine end is determined and the temperature can only be reduced by transferring heat through the design of the turbocharger itself. For the intermediate shell of the non-water-cooling structure, it is generally difficult to balance the temperature between the bearing system and the vortex end sealing system, which is usually the trade-off, thereby limiting the durability or sealing performance of the supercharger to a certain extent.

FIG. 2 illustrates a cross-sectional view of an exemplary turbocharger. Fig. 3 shows a partial enlarged view of the volute region a of the turbocharger in fig. 2.

The following describes the present invention with reference to fig. 2 and 3.

In the example of fig. 3, the present embodiment provides a turbocharger arrangement, in particular a turbine end assembly of a turbocharger, comprising: an intermediate housing 1, a turbine shaft 2 disposed inside the intermediate housing 1, and a turbine end bearing 3 disposed between the intermediate housing 1 and the turbine shaft 2, the turbine end bearing 3 being for rotatably supporting the turbine shaft 2.

The intermediate housing 1 is provided at the turbine end with a turbine end shaft bore 11 for accommodating the turbine shaft 2, which turbine end shaft bore 11 is embodied as an opening of the intermediate housing 1 at the turbine end of the turbine shaft bore. The intermediate housing 1 is provided internally with a bearing housing 12 for accommodating the bearing 3, and a lubricant opening communicating with the lubricant passage in the intermediate housing 1 is also formed in the bearing housing 12. Lubricant can flow out of the lubricant opening to lubricate the bearing 3 and out of the turbocharger from oil return grooves 17 below the center housing 1. The intermediate housing 1 is provided with a cavity 13 between the scroll shaft hole 11 and the bearing housing 12, the cavity 13 communicating with the oil return groove 17, and a dome area 14 formed on a side close to the scroll shaft hole 11. The dome region 14 is a dome-shaped concave surface formed on the side of the cavity 13 of the intermediate shell 1 near the turbine.

The dome region 14 described above can be understood as a cavity wall formed at the left side of the cavity 13 of the intermediate housing 1, like a dome, the dome-shaped concave surface facilitating the flow and cooling of the lubricant due to its structural design conforming to fluid mechanics.

The middle shell 1 is further provided with an annular groove structure 15 formed on the dome region 14 and extending towards the inside of the middle shell along the scroll-end shaft hole 11, and a gap is formed between the groove structure 15 and the bearing seat 12. The groove structure 15 is understood to be an annular boss structure, the outer side wall and the dome region of which form an annular groove, and the inner side wall of which extends from the inner side wall of the turbine-end shaft hole 11. Further, the channel structure 15 of the intermediate shell 1 may be integrally cast by a mold.

It will be appreciated that the intermediate casing of a conventional turbocharger is generally not provided with a groove structure 15 as shown in fig. 3 or 3. Although heat transfer can be reduced by providing a heat shield between the turbine and the intermediate casing, heat is still transferred from the connecting flange to the turbine end sealing system where the seal ring is installed through the heat shield, the turbine end side wall of the intermediate casing and the turbine shaft, a gap exists between the bearing seat of the intermediate casing and the turbine end side wall of the intermediate casing for reducing the heat transfer from the turbine end to the bearing seat, and the heat transferred from the turbine end is concentrated on the turbine end side wall of the intermediate casing, thereby further increasing the temperature at the turbine end sealing system.

In the embodiment of the present application, when the turbocharger structure having the groove structure 15 shown in fig. 3 is adopted, firstly, due to the addition of the groove structure 15, the material for receiving heat near the seal ring 4 becomes larger, and the heat transfer to the seal ring 4 is reduced. Secondly, lubricant will flow along the dome region 14 formed at the vortex end of the intermediate shell 1, increasing the contact area between the lubricant and the dome region 14 by introducing the channel structure 15, facilitating the heat transfer from the vortex end to the dome region to be carried away by the flowing lubricant. Therefore, the temperature of the vortex end sealing system is effectively reduced.

Meanwhile, since there is still a certain gap between the groove structure 15 of the middle housing 1 and the bearing seat 18, the high temperature of the vortex end is difficult to be directly transferred to the bearing seat 12, and thus the temperature of the bearing system does not increase significantly.

It will be appreciated that in the embodiments of the present application, heat transfer may still be further reduced by providing a heat shield 5 or other known means of thermal insulation between the turbine and the intermediate casing 1.

In an embodiment of the present application, the inner side surface of the groove structure 15 and/or the turbine-end shaft hole 11 and the outer side surface of the turbine shaft 2 are provided with labyrinth structures which are engaged with each other to realize

In the example of fig. 3, the groove structure 15 and the inner side surface of the turbine end shaft hole 11 and the outer side surface of the turbine shaft 2 may be provided with labyrinth structures that cooperate with each other. The labyrinth seal structure may be constituted by the scroll end shaft hole 11, the stepped hole 14 provided on the inner side surface of the groove structure 15, two scroll end seal ring groove 21 structures on the turbine shaft 2, and the seal rings 4 fitted in the respective scroll end seal ring grooves 21. The stepped hole 14 has a smaller bore diameter than the turbine-end shaft hole 11, and the outer diameter of the seal ring 4 is larger than the bore diameter of the stepped hole 14, so that the seal ring 4 can be fixed to the orifice of the stepped hole. In other examples, the labyrinth seal structure may also be formed entirely on the inside surface of the groove structure 15, i.e. further away from the turbine end than in the position in fig. 3. Alternatively, the stepped hole 14 may be provided on the inner side surface of the turbine-end shaft hole 11, i.e., more toward the turbine end than the position in fig. 3.

Since the inner side surface of the groove structure 15 extends from the inner side surface of the scroll shaft hole 11, the labyrinth structure may be disposed at any suitable position on the inner side surfaces of the groove structure 15 and the scroll shaft hole 11, which is not particularly limited in the present application.

Regarding the number of the turbine end seal ring groove 21 and the seal ring 4 fittingly installed in the turbine end seal ring groove 21 on the turbine shaft 2, the present embodiment is not particularly limited, and may be one or more. It can be understood that the more sealing rings 4, the better the vortex end sealing effect.

In an embodiment of the present application, referring to fig. 3, one or more tip seal ring grooves 21 on the turbine shaft 2 and the seal ring 4 mounted on the tip seal ring groove 21 may be covered by the groove structure 15 of the intermediate casing 1. In other words, by introducing the groove structure 15, the seal ring 4 can be moved away from the high-temperature vortex end to reduce the temperature.

Alternatively, one or more tip seal ring grooves 21 on the turbine shaft 2 and the seal ring 4 mounted on the tip seal ring grooves 21 may not be covered by the groove structure 15 described above, but still covered by the inside surface of the tip shaft hole 11 of the intermediate shell 1.

In an embodiment of the present application, referring to fig. 3, an oil slinger structure 22 may also be formed on the turbine shaft 2, the oil slinger structure 22 being located in the gap between the groove structure 15 and the bearing housing 12. It will be appreciated that the flow of lubricant within the cavity is further facilitated by the oil slinger structure 22 disposed above the turbine shaft 2, so that heat transferred in the vicinity of the dome region 14 can be carried away by the lubricant, further reducing the heat.

In an embodiment of the present invention, the radial thickness S of the groove structure 15 is 0.5 to 1.5H, and the axial thickness H of the groove structure 15 is 0.4 to 1.0H; where h is the minimum axial groove width of the tip seal ring groove 21 on the turbine shaft 2.

Fig. 4 shows a sectional view of an intermediate housing 1 of an exemplary turbocharger. The following describes the present invention with reference to fig. 4.

In the example of fig. 4, there is provided an intermediate housing 1 of a turbocharger, the intermediate housing 1 being provided at a turbine end thereof with a turbine end shaft hole 11 for accommodating a turbine shaft 2, a bearing housing 12 for accommodating a bearing 3 therein, and a cavity 13 being provided between the turbine end shaft hole 11 and the bearing housing 12, the cavity 13 forming a dome region 14 on a side close to the turbine end shaft hole 11; wherein the middle shell 1 is further provided with an annular groove structure 15 formed on the dome area 14 and extending along the scroll end shaft hole 11 towards the bearing seat 12, and a gap is formed between the groove structure 15 and the bearing seat 12.

When using the intermediate housing 1 shown in fig. 4 with the groove structure 15, firstly, due to the addition of the groove structure 15, the material for receiving heat near the sealing ring 4 is increased, and the heat transfer to the sealing ring is reduced. Secondly, the lubricant will flow along the domed region formed at the volute end of the intermediate shell, facilitating the heat transferred to the domed region by the volute end to be carried away by the flowing lubricant. Therefore, by using the intermediate shell 1, the temperature of the vortex end sealing system can be effectively reduced. Meanwhile, because a certain gap is still left between the groove structure 17 of the middle shell 1 and the bearing seat 18, the high temperature of the vortex end is difficult to be directly transmitted to the bearing seat 12, and therefore, the temperature of the bearing system is not obviously increased.

According to an embodiment of the present application, the groove structure 15 and/or the inner side surface of the turbine-end shaft hole 11 is further provided with a sealing structure for forming a labyrinth sealing structure cooperating with another sealing structure provided on the outer side surface of the turbine shaft 2.

According to an embodiment of the present application, the inner side surface of the groove structure 15 of the intermediate housing 1 is formed with a stepped hole 14, such that the groove structure 15 is configured to cover one or more turbine-end seal ring grooves 21 on the turbine shaft 2 and the seal ring 4 mounted on the turbine-end seal ring grooves 21.

According to an embodiment of the present application, the inner side surface of the scroll end shaft hole 11 of the intermediate housing 1 is formed with a stepped hole 14 such that the scroll end shaft hole 11 is configured to cover one or more scroll end seal ring grooves 21 on the turbine shaft 2 and the seal ring 4 mounted on the scroll end seal ring grooves 21.

According to an embodiment of the present disclosure, the radial thickness S of the groove structure 15 is 0.5 to 1.5H, and the axial thickness H of the groove structure 15 is 0.4 to 1.0H; where h is the minimum axial groove width of the tip seal ring groove 21 on the turbine shaft 2.

According to an embodiment of the application, the cavity in the intermediate shell 1 extends from the dome area 14 in a direction away from the vortex end.

It will be appreciated that other configurations of turbochargers according to embodiments of the present application, such as turbines and the like, are known in the art and will not be described in detail herein.

In the description herein, references to the description of the term "an embodiment," "some embodiments," "an illustrative embodiment," "an example," "a specific example," or "some examples" or the like mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

While the spirit and principles of the invention have been described with reference to several particular embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, nor is the division of aspects, which is for convenience only as the features in such aspects may not be combined to benefit. The invention is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.

Claims

1. A turbocharger structure, characterized by comprising:

an intermediate housing (1), a turbine shaft (2) arranged inside the intermediate housing (1), and a bearing (3) arranged between the intermediate housing (1) and the turbine shaft (2);

the middle shell (1) is provided with a turbine end shaft hole (11) used for accommodating the turbine shaft (2) at a turbine end, a bearing seat (12) used for accommodating the bearing (3) is arranged in the middle shell, a cavity (13) is arranged between the turbine end shaft hole (11) and the bearing seat (12), and a dome area (14) is formed on one side, close to the turbine end shaft hole (11), of the cavity (13);

the middle shell (1) is further provided with an annular groove structure (15) formed by extending towards the inside of the middle shell along the vortex end shaft hole (11) on the dome area (14), and a gap is reserved between the groove structure (15) and the bearing seat (12).

2. The turbocharger arrangement according to claim 1, characterized in that the groove arrangement (15) and/or the inner side surface of the turbine-end shaft bore (11) and the outer side surface of the turbine shaft (2) are provided with cooperating labyrinth arrangements.

3. The turbocharger arrangement according to claim 2, characterised in that one or more turbine end sealing ring grooves (21) on the turbine shaft (2) and the sealing rings (4) mounted on the turbine end sealing ring grooves (21) are covered by the groove arrangement (15) of the intermediate housing (1).

4. The turbocharger arrangement according to claim 2, characterized in that one or more scroll end seal ring grooves (21) on the turbine shaft (2) and the seal ring (4) mounted on the scroll end seal ring grooves (21) are covered by the inside surface of the scroll end shaft hole (11) of the intermediate housing (1).

5. The turbocharger arrangement according to claim 1, characterized in that an oil slinger arrangement (22) is formed on the turbine shaft (2), which oil slinger arrangement (22) is located in the gap between the groove arrangement (15) and the bearing housing (12).

6. The turbocharger arrangement as claimed in claim 1, characterized in that the radial wall thickness S of the groove arrangement (15) is 0.5 to 1.5H, and the axial thickness H of the groove arrangement (15) is 0.4 to 1.0H; wherein h is the minimum axial groove width of a vortex end sealing ring groove (21) on the turbine shaft (2).

7. An intermediate housing of a turbocharger, characterized in that the intermediate housing is provided at its turbine end with a turbine end shaft bore (11) for accommodating a turbine shaft (2), in the interior of which a bearing seat (12) for accommodating a bearing (3) is provided, and in that a cavity (13) is provided between the turbine end shaft bore (11) and the bearing seat (12), which cavity (13) forms a dome region (14) on the side close to the turbine end shaft bore (11);

the middle shell is further provided with an annular groove structure (15) formed by extending along the vortex end shaft hole (11) towards the direction of the bearing seat (12) on the dome area (14), and a gap is reserved between the groove structure (15) and the bearing seat (12).

8. An intermediate housing as claimed in claim 7,

the inner side surface of the groove structure (15) and/or the turbine end shaft hole (11) is further provided with a sealing structure which is used for forming a labyrinth sealing structure matched with another sealing structure arranged on the outer side surface of the turbine shaft (2).

9. An intermediate housing as claimed in claim 8,

the inner side surface of the groove structure (15) of the intermediate casing is formed with a stepped hole (14) so that the groove structure (15) is configured to cover one or more scroll end seal ring grooves (21) on the turbine shaft (2) and a seal ring (4) mounted on the scroll end seal ring grooves (21).

10. An intermediate housing as claimed in claim 8,

the inner side surface of the turbine-end shaft hole (11) of the intermediate shell is formed with a stepped hole (14) so that the turbine-end shaft hole (11) is configured to cover one or more turbine-end seal ring grooves (21) on the turbine shaft (2) and a seal ring (4) mounted on the turbine-end seal ring grooves (21).

11. An intermediate shell according to claim 7, wherein the radial wall thickness S of the groove structure (15) is 0.5 to 1.5H, and the axial thickness H of the groove structure (15) is 0.4 to 1.0H; wherein h is the minimum axial groove width of a vortex end sealing ring groove (21) on the turbine shaft (2).