KR101855610B1 - Labyrinth seal, centrifugal compressor, and supercharger - Google Patents

Abstract

The labyrinth seal used in the centrifugal compressor includes a bladed wheel in which the fluid flows in the radial direction and a stop member formed on the back side of the bladed wheel. The labyrinth seal may include a plurality of first convex portions each formed along the circumferential direction at a plurality of radial positions on the back surface of the vane wheel and a plurality of second convex portions formed between the first convex portions and the second convex portion, And a plurality of second convex portions formed along the circumferential direction on the member. A flow path on a labyrinth path including a plurality of minimum clearance portions formed between the first convex portion and the second convex portion is formed between the back surface of the vane wheel and the stop member along the radial direction. Wherein the stop member is located on the upstream side of the minimum clearance portion in the flow direction of the leakage flow passing through the minimum clearance portion formed between the first convex portion and the second convex portion, The backside of the car is located.

Description

[0001] LABORRINTH SEAL, CENTRIFUGAL COMPRESSOR, AND SUPERCHARGER [0002]

The present disclosure relates to a labyrinth seal extending in the radial direction of a centrifugal compressor, and to a centrifugal compressor and a supercharger having the labyrinth seal.

Generally, the centrifugal compressor of the supercharger is configured to pressurize the air introduced into the centrifugal compressor by the impeller. The high-temperature and high-pressure combustion gas generated by the combustion is passed through the turbine of the supercharger to rotate the shaft connected to the turbine to drive the centrifugal compressor formed at the other end of the shaft .

In such a centrifugal compressor, a labyrinth seal may be formed between a rotating member including a bladed wheel and a stationary member including a bearing casing. For example, Patent Document 1 describes a labyrinth seal disposed on an impeller rear wall of a centrifugal compressor of an exhaust turbine turbocharger. In this configuration, the leakage flow of the compressed fluid compressed when passing through the impeller through the back side of the impeller is suppressed.

Typically, the labyrinth seal has a configuration in which a narrowed region and a fluid expansion region are alternately formed. Thereby, the leakage amount of the fluid from the centrifugal compressor can be suppressed. In addition, since the fluid leaking from the labyrinth seal gradually decreases in pressure, the pressure on the back surface of the vane car can be lowered. In the supercharger equipped with the centrifugal compressor, there is a case where a thrust acting from the turbine side toward the compressor side acts by the hydraulic force acting on the turbine of the turbocharger. In this case, lowering the pressure on the vane car rear surface maintains the thrust balance appropriately .

Japanese Patent Application Laid-Open No. 11-247618

However, in the labyrinth seal as described above, the temperature of the leakage flow rises due to the fluid friction in the narrowed flow path, and the amount of heat transferred to the blade lane increases. The wing car is a component that acts by high centrifugal stress due to rotation. When the temperature rises due to the amount of heat, the possibility of creep rupture increases. For this reason, there is a demand for a labyrinth seal having a high sealing property and a small heat transfer capability as a wing lid.

Regarding this point, in the labyrinth seal of Patent Document 1, a swirl chamber is formed on the downstream side of the throttle point (narrowed region), and a part of the fluid passing through the throttle point is swirled in the swirl chamber To join the remaining fluids. Thus, heat input to the blade side is suppressed to some extent.

However, since the pressure ratio tends to increase from the viewpoint of improving the efficiency of the centrifugal compressor, it is desired to further suppress the heat input to the blade side.

In view of the above-described circumstances, at least one embodiment of the present invention provides a labyrinth seal capable of reducing the amount of heat input into a blade from a fluid passing through the labyrinth seal, and a centrifugal compressor and a supercharger having the same. .

(1) A labyrinth seal according to at least one embodiment of the present invention,

A labyrinth seal for use in a centrifugal compressor comprising a bladed wheel in which a fluid flows in a radial direction and a stop member formed on a back side of the bladed wheel,

A plurality of first convex portions formed along the circumferential direction at a plurality of radial positions on the back surface of the vane car,

And a plurality of second convex portions formed along the circumferential direction on the stop member so that the front end portion enters between the adjacent first convex portions,

A flow path on a labyrinth path including a plurality of minimum clearance portions formed between the first convex portion and the second convex portion is formed between the rear surface of the vane wheel and the stop member along the radial direction,

Wherein the stop member is located on the upstream side of the minimum clearance portion in the flow direction of the leakage flow passing through the minimum clearance portion formed between the first convex portion and the second convex portion, And the rear surface of the vehicle is positioned.

As a result of intensive studies, the inventors of the present invention have found that when one of the causes of heat input to the blade of a conventional labyrinth seal is that a fluid having a high flow velocity passing through the minimum clearance portion collides against the wall surface of the stationary member side, And that the fluid in the vicinity of the wall surface of the stationary member having a relatively high total temperature as viewed from the wing car side is conveyed to the wing car side.

The construction of the above (1) is based on this finding by the present inventors, and is characterized in that the stop member is located on the upstream side of the minimum clearance portion in the flow direction of the leakage flow passing through the minimum clearance portion, And the rear surface of the vane car is positioned on the downstream side. Therefore, the fluid accelerated when passing through the minimum clearance portion flows along the back side of the impeller after colliding against the back side of the impeller, not on the stationary member side. Therefore, it is possible to suppress the situation that the fluid in the vicinity of the wall surface of the stationary member having a relatively high relative temperature from the wing car side is conveyed to the blade side with the fluid having the high flow velocity passing through the minimum clearance portion. Therefore, the amount of heat input into the blades from the fluid passing through the labyrinth seal can be reduced, and the temperature rise of the blades can be suppressed.

(2) In some embodiments, in the configuration (1), the labyrinth seal is configured to seal the leakage flow directed radially inward between the back surface of the vane wheel and the stop member And the minimum clearance portion is formed between a tip of the first convex portion or a radially inward surface of the first convex portion and the second convex portion.

According to the structure (2), it is possible to realize a flow toward the rear side of the impeller of the fluid on the downstream side of the minimum clearance portion in the labyrinth seal for sealing the leakage flow toward the radially inward side. Thereby, the amount of heat input into the blade of the fluid passing through the labyrinth seal can be reduced, and the temperature rise of the blade wheel can be suppressed.

(3) In one embodiment, in the configuration of (2), a seal end is formed at the tip of the second convex portion, and the minimum clearance portion is formed in the radially inner surface of the first convex portion, And between the seal end of the second convex portion.

According to the structure (3), since the seal end is formed in the second convex portion on the stationary member side, it is possible to prevent the flow of fluid passing through the minimum clearance portion on the downstream side of the minimum clearance portion, Wall) is remote. Therefore, it is possible to effectively suppress the situation in which the fluid is conveyed to the blade side with a fluid having a high flow velocity passing through the minimum clearance portion. Therefore, the amount of heat input into the blades from the fluid passing through the labyrinth seal can be effectively reduced, and the temperature rise of the blades can be further suppressed.

(4) In one embodiment, in the configuration (3), the radially inner surface of the first convex portion forms a sealing surface extending along the axial direction of the centrifugal compressor, 2 convex portion is formed so as to protrude from the stationary member toward the rear side and the radially outer side of the vane car.

According to the structure (4), since the clearance width direction of the minimum clearance portion is along the radial direction, the clearance width of the minimum clearance portion is not affected well even if the blades are shifted in the axial direction. Therefore, it is possible to suppress the deterioration of the seal performance due to the displacement of the axial position of the impeller.

(5) In another embodiment, in the structure of (2), a seal end is formed at the tip of the first convex portion, and the minimum clearance portion is formed at a position between the seal end of the first convex portion and the second convex portion And is formed between the radially outer surfaces.

According to the configuration (5), the fluid that has passed through the minimum clearance portion formed between the seal end of the first convex portion on the blade side and the surface on the radially outer side of the second convex portion of the stop member can be directed toward the blade side have. Thereby, the amount of heat input into the blade of the fluid passing through the labyrinth seal can be reduced, and the temperature rise of the blade wheel can be suppressed.

(6) In one embodiment, in the configuration of (5), a seal end is formed at the tip end of the first convex portion, and the minimum clearance portion is formed at a position between the seal end of the first convex portion and the second convex portion And is formed between the radially outer surfaces.

According to the configuration of (6), since the clearance width direction of the minimum clearance portion is along the radial direction, the clearance width of the minimum clearance portion is not affected even if the blades are shifted in the axial direction. Therefore, it is possible to suppress the deterioration of the seal performance due to the displacement of the axial position of the impeller.

(7) A centrifugal compressor according to at least one embodiment of the present invention,

A wing car in which the fluid flows in the radial direction,

A stationary member formed on the back side of the vane car,

And a labyrinth seal according to any one of (1) to (6), which is formed between the back surface of the vane wheel and the stop member.

According to the structure (7), the amount of heat input into the vane lane from the fluid passing through the labyrinth seal can be reduced, and the temperature rise of the vane wheel can be suppressed. Therefore, it is possible to suppress the deterioration of the creep life due to the high temperature of the impeller, and it is possible to realize the high pressure of the centrifugal compressor.

(8) The supercharger according to at least one embodiment of the present invention,

A compressor for compressing the intake air into the internal combustion engine and including a centrifugal compressor described in (7) above;

And a turbine driven by the exhaust gas of the internal combustion engine and configured to drive the compressor.

According to the structure (8), by reducing the amount of heat input into the blades from the fluid passing through the labyrinth seal, the high pressure of the centrifugal compressor can be realized and the performance of the supercharger can be improved.

According to at least one embodiment of the present invention, it is possible to reduce the amount of heat input into the blades from the fluid passing through the labyrinth seal, thereby suppressing the temperature rise of the blades. Therefore, it is possible to suppress the deterioration of the creep life due to the high temperature of the impeller.

1 is a cross-sectional view showing an entire configuration of a supercharger according to an embodiment.
FIG. 2A is a longitudinal sectional view showing a labyrinth seal according to an embodiment, which is a rear periphery of a wing car. FIG.
Fig. 2B is a plan view of the vane wheel shown in Fig. 2A as viewed from the back (A direction).
3 is a schematic cross-sectional view of a wing car and a stationary member, showing a labyrinth seal according to one embodiment.
4 is an enlarged cross-sectional view of the labyrinth seal shown in Fig.
5 is an enlarged cross-sectional view of a labyrinth seal according to another embodiment.
6 is a view showing the distribution of velocity in the meridional plane among the flow analysis results in the labyrinth seal.
Fig. 7 is a view showing the relative temperature distribution in the results of the flow analysis in the labyrinth seal. Fig.

Hereinafter, some embodiments of the present invention will be described with reference to the accompanying drawings. However, the dimensions, materials, shapes, relative arrangements and the like of the constituent parts described in the embodiments or shown in the drawings are not intended to limit the scope of the present invention but are merely illustrative examples.

First, referring to Fig. 1, a turbocharger 1 to which a labyrinth seal 10 according to the present embodiment is applied will be described. Fig. In the figure, specifically, the labyrinth seal 10 is applied to the centrifugal compressor 3 of the turbocharger 1. Further, the application of the labyrinth seal 10 is not limited to the illustrated centrifugal compressor 3, but may be applied to other types of centrifugal compressors.

1 is a cross-sectional view (vertical cross-sectional view) showing an overall configuration of a supercharger 1 according to one embodiment, and shows an exhaust turbine supercharger for a ship as an example.

As shown in the figure, a turbocharger 1 (hereinafter referred to as a turbine) configured to be driven by an exhaust gas from an internal combustion engine (for example, a marine diesel engine) , And a centrifugal compressor (3) driven by the turbine (2) and configured to compress the intake air supplied to the internal combustion engine.

As a specific configuration example, a bearing stand 4 is formed between the turbine 2 and the centrifugal compressor 3. [ The turbine casing 21 of the turbine 2, the bearing stand 4 and the compressor casing 31 of the centrifugal compressor 3 are integrally constituted by connecting means such as fastening members (e.g., bolts). The thrust bearing 41 and the radial bearings 42 and 43 are accommodated in the bearing base 4. The thrust bearing 41 and the radial bearings 42 and 43 support the rotor 5 so as to freely rotate. The rotor 5 is connected to the rotor 24 of the turbine 2 at one end and connected to the blades 32 of the centrifugal compressor 3 at the other end.

The turbine 2 is configured to be driven by the exhaust gas of an internal combustion engine (not shown) to drive the centrifugal compressor 3. Specifically, the turbine 2 includes a rotor 5 (actually one end side of the rotor 5), a plurality of rotor blades 24 formed in the outer periphery of the rotor 5, And a turbine casing 21 formed on an outer peripheral side of the turbine casing. The inlet passage 27 and the axial passage 28 and the outlet passage 29 through which the exhaust gas flows are formed in order in the flow direction of the exhaust gas by the stop member including the turbine casing 21 . The axial passage 28 is located between the inlet passage 27 and the outlet passage 29 and extends along the rotational axis O of the rotor 5. A rotor 24 is formed in the axial passage. A turbine nozzle (stator blade) 25 is formed at the inlet side of the rotor 24.

In this turbine 2, the exhaust gas from the internal combustion engine is introduced from the inlet passage 27 and the rotor 5 connected to the rotor 24 is rotated by the exhaust gas flowing through the axial passage 28 have. The exhaust gas that has passed through the rotor 24 passes through the outlet passage 29 and is discharged.

The centrifugal compressor 3 is configured to compress intake air into an internal combustion engine (not shown), and includes a rotor 5 (actually the other end of the rotor 5) And a compressor casing 31 formed on the outer circumferential side of the rotor 5 and the blades 32. An air inlet (37) and an outlet scroll (38) are formed by a stop member including a compressor casing (31). Between the air inlet 37 and the outlet scroll 38, the impeller 32 and the diffuser 36 are arranged in this order in the air flow direction (radial direction of the centrifugal compressor 3). The wing car 32 includes a disk-shaped hub 33 fixed to the outer periphery of the rotor 5 and a plurality of vanes (not shown) fixed to the hub 33 and arranged radially with respect to the hub 33 34). A fluid (here, air) flows in the vane wheel 32 in the radial direction. 1 illustrates a single-stage centrifugal compressor, it may also be a multi-stage centrifugal compressor.

In the centrifugal compressor 3, the air introduced from the air inlet 37 is pressurized when it passes through the impeller 32, the diffuser 36, and the outlet scroll 38. Most of the air compressed in the centrifugal compressor (3) is guided to the engine cylinder of the internal combustion engine and performs the operation of pressing down the piston by the combustion / expansion stroke. The high-temperature and high-pressure combustion gas generated here is sent to the turbine 2, and is driven by the turbine 2 to drive the coaxial centrifugal compressor 3.

A lubricant supply passage 44 is formed in the bearing base 4. One end side of the lubricating oil supply passage 44 is connected to a lubricating oil supply portion (for example, an oil tank and an oil pump). The other end side of the lubricating oil supply passage 44 is branched into a plurality of branches and the branched ends are connected to the thrust bearing 41 and the radial bearings 42 and 43, respectively. Lubricating oil is supplied to the thrust bearing 41 and the radial bearings 42, 43 through the lubricating oil supply passage 44, respectively.

In the supercharger 1 having such a construction as described above, a labyrinth seal 10 is formed between the centrifugal compressor 3 and the bearing base 4. Specifically, the labyrinth seal 10 is configured to seal between the bladed wheel 32 and the stationary member 46 of the bearing base 4 facing the bladed wheel 32. As shown in Fig.

This labyrinth seal 10 mainly prevents the air containing the lubricating oil inside the bearing bush 4 from being mixed into the compressed air of the centrifugal compressor 3. [ There may be a case where the mist space in which the lubricant is scattered is filled in the inner space of the bearing base 4. A part of the high-pressure compressed air that has passed through the impeller 32 is supplied to the rear surface of the impeller 32 through the labyrinth seal 10 in order to prevent the mist from being mixed into the compressed air of the centrifugal compressor 3. [ The space between the flow path of the compressed air in the centrifugal compressor 3 and the inner space of the bearing base 4 is sealed.

In the supercharger 1, part of the discharged air from the bladed wheel 32 may go back to the back surface and may leak into the internal space of the bearing base 4 in some cases. In this case, the rear surface of the bladed wheel 32 becomes a high pressure, and the bladed wheel 32, in the direction of the rotation axis O of the rotor 5, A force acts. This high thrust force may lead to enlargement of the thrust bearing 41 and high friction loss. Therefore, also from the viewpoint of the balance of the trust, it is preferable to lower the pressure of the back surface of the vane wheel 32 by the labyrinth seal 10. [

Hereinafter, the labyrinth seal 10 according to the present embodiment will be described in detail with reference to Figs. 2A and 2B to 5. 2A is a longitudinal cross-sectional view of a rear surface of a vane wheel 32 showing a labyrinth seal 10 according to an embodiment. Fig. 2B is a plan view of the vane wheel 32 shown in Fig. 2A when viewed from the back (A direction) 35 side. 3 is a schematic cross-sectional view of a wing car 32 and a stop member 46, showing a labyrinth seal 10 according to one embodiment. 4 and 5 are enlarged cross-sectional views of the labyrinth seal 10 in each embodiment.

As shown in Figs. 2A and 2B to 5, the labyrinth seal 10 according to this embodiment includes a blade 32 in which a fluid (e.g., air) flows in a radial direction, And a stop member 46 formed on the back surface 35 side of the centrifugal compressor. The labyrinth seal 10 seals the space between the back surface 35 of the bladed wheel 32 and the stop member 46 in the radial direction of the centrifugal compressor.

In some embodiments, the labyrinth seal 10 includes a plurality of first convex portions 11 formed on the back surface 35 of the vane wheel 32, and a plurality of second convex portions 11 formed on the stop member 46. [ And includes a convex portion 12. Between the first convex portion 11 and the second convex portion 12, a flow passage 15 in the form of a labyrinth is formed along the radial direction.

The plurality of first convex portions 11 are formed along the circumferential direction at a plurality of radial positions on the back surface 35 of the vane wheel 32. [ For example, as shown in Fig. 2B, a plurality of first convex portions 11 are formed annularly around the rotational axis O of the rotor 5 as a center. That is, a plurality of first convex portions 11 are formed concentrically.

The plurality of second convex portions 12 are formed along the circumferential direction on the stopper member 46 so that the front end portions enter between the adjacent first convex portions 11. [ For example, a plurality of second convex portions 12 are formed annularly around the rotational axis O of the rotor 5 so as to correspond to the plurality of first convex portions 11 shown in Fig. 2B have. That is, the plurality of second convex portions 12 are formed concentrically.

2A and 2B to 5, there is shown a configuration in which one second convex portion 12 is disposed between two neighboring first convex portions 11 in the radial direction, that is, A configuration in which the convex portion 11 and the second convex portion 12 are alternately arranged one by one is illustrated. However, it is sufficient that at least one second convex portion 12 is disposed between two neighboring first convex portions 11, for example, two adjacent first convex portions 11 in the radial direction The two second convex portions 12 may be disposed between the two convex portions 12.

2A and 2B to 5, the rear surface 35 of the vane wheel 32 is formed so as to be perpendicular to the rotational axis O of the rotor 5. In this case, the arranging direction of the plurality of first convex portions 11 in the radial direction and the arranging direction of the plurality of second convex portions 12 in the radial direction are all set to be equal to the rotational axis O of the rotor 5 In the direction orthogonal to the direction of the arrow A. The arrangement direction of the plurality of first convex portions 11 or the plurality of second convex portions 12 may be inclined with respect to a plane perpendicular to the rotation axis O. [ For example, the plurality of first convex portions 11 or the plurality of second convex portions may be inclined in a direction inclined so as to be distant from the inlet side of the vane wheel 32 in the axial direction from the radially outer side toward the inner side Or may be arranged along the same direction.

The inventors of the present invention have made intensive studies to reduce the amount of heat input into the vane wheel 32 from the fluid passing through the flow path 15 in the labyrinth seal 10 having the above configuration. .

The inventors of the present invention performed a flow analysis using a labyrinth seal 50 as a comparative example to calculate a flow velocity distribution and a temperature distribution in the flow path 51 of the labyrinth seal 50.

6 is a view showing the flow velocity distribution in the meridian plane among the flow analysis results in the labyrinth seal 50. Fig. 7 is a view showing the relative temperature distribution among the results of the flow analysis in the labyrinth seal 50. Fig. 6 and 7, the labyrinth seal 50 of the comparative example has the first convex portion 52 on the back side of the vane wheel 32 and the second convex portion 52 of the stop member 46 53 are arranged alternately in the radial direction. The flow path 51 between the first convex portion 52 and the second convex portion 53 is located between the radially outer surface of the first convex portion 52 and the front end portion of the second convex portion 53 A minimum clearance portion 54 is formed.

As shown in Fig. 6, the flow velocity distribution in the flow path 51 has the highest flow velocity at the minimum clearance portion 54. As shown in Fig. On the downstream side of the minimum clearance portion 54, an expansion region 55 formed by the space between the adjacent second convex portions 53 and the front end of the first convex portion 52 is located. In general, the fluid that is inherently fluidized in the minimum clearance portion 54 is rapidly decelerated in the expansion region 55. By repeating this, it is known that the pressure of the fluid gradually decreases. 6, the fluid having a high flow rate that has actually passed through the minimum clearance portion 54 collides against the wall surface 56 on the side of the stop member 46 and is returned to the side of the vane car 32 In the case of the flow path, the flow rate is relatively high.

On the other hand, as shown in Fig. 7, a region where the relative temperature is relatively high in the flow path 51 is present on the side of the stationary member 46. [ This is because the fluid in the vicinity of the stop member 46 has a small flow velocity in the absolute system and a large flow velocity in the rotating coordinate system rotating together with the vane wheel 32, , And the relative temperature increases with respect to the fluid on the side of the rotating wall surface (the back surface side of the vane wheel 32).

6, in the labyrinth seal 50 in the comparative example, a fluid having a high flow velocity that has passed through the minimum clearance portion 54 in the flow path 51 is supplied to the wall surface of the stop member 46 side There is a flow of a relatively intrinsic velocity that collides with the impeller body 56 and returns to the impeller 32 side. Therefore, when a fluid having a high flow rate that has passed through the minimum clearance portion 54 collides against the wall surface 56 on the side of the stop member 46 and flows on the wall surface 56, It is conceivable that the fluid in the vicinity of the wall surface 56 of the high static member 46 is conveyed to the side of the blades 32. The inventors of the present invention have found that this is one of the causes of increase in heat input to the blades 32 in the labyrinth seal 50.

4 and 5, the labyrinth seal 10 according to the present embodiment is conceived based on the above-described knowledge by the inventors of the present invention, and further has the following configuration.

A plurality of minimum clearances formed between the first convex portion 11 and the second convex portion 12 are formed between the back surface 35 of the vane wheel 32 and the stop member 46. In this embodiment, And a flow path 15 on the labyrinth containing the part 16 is formed along the radial direction.

In the flow direction of the leakage flow passing through the minimum clearance portion 16 formed between the first convex portion 11 and the second convex portion 12, And the back surface 35 of the vane car 32 is positioned on the downstream side of the minimum clearance portion 16. [

The stop member 46 is located on the upstream side of the minimum clearance portion 16 and the downstream side of the minimum clearance portion 16 is located on the downstream side of the minimum clearance portion 16 in the flow direction of the leakage flow passing through the minimum clearance portion 16. [ The back surface 35 of the vane wheel 32 is positioned. The fluid accelerated at the time of passing through the minimum clearance portion 16 collides against the back surface 35 of the bladed wheel 32 and not the back surface 35 of the bladed wheel 32 ). The fluid in the vicinity of the wall surface of the static member 46 having a relatively high relative temperature from the side of the impeller 32 is conveyed to the side of the impeller 32 accompanied by the fluid having the high flow velocity passing through the minimum clearance portion 16 The situation can be suppressed. Therefore, the amount of heat input from the fluid passing through the labyrinth seal 10 to the vane wheel 32 can be reduced, and the temperature rise of the vane wheel 32 can be suppressed.

In one embodiment, the labyrinth seal 10 is configured to seal radially inward leakage flow between the back 35 of the vane 32 and the stop 46, and the minimum clearance portion 16 may be formed between the tip end of the first convex portion 11 or the inside surface in the radial direction of the first convex portion 11 and the second convex portion 12.

According to the above configuration, in the labyrinth seal 10 for sealing the leakage flow toward the radially inward direction, the flow toward the back surface 35 of the fluid blades 32 on the downstream side of the minimum clearance portion 16 Can be realized. Thereby, the amount of heat input from the fluid passing through the labyrinth seal 10 to the impeller 32 can be reduced, and the temperature rise of the impeller 32 can be suppressed.

Specifically, as shown in Figs. 4 and 5, when the fluid flows from the radially outer side to the inner side in the flow path 15, the inner side in the radial direction of the first convex portion 11 The minimum clearance portion 16 is formed by the front end (end side) of this surface side and the radially outer surface or the front end (end side) of the second convex portion 12. When the fluid flows from the radially outer side to the inner side, the fluid flowing along the radially inner surface of the first convex portion 11 or the radially outer surface of the second convex portion 12 Flows toward the vane wheel 32 side from the stop member 46 side. Therefore, by forming the minimum clearance portion 16 on the flow path that flows from the stationary member 46 side toward the vane wheel 32, the minimum clearance portion 16 is formed on the flow path of the stationary member 46 having a relatively high relative- It is possible to suppress the situation that the fluid in the vicinity of the wall surface is conveyed to the side of the blade 32 accompanied by the fluid having a high flow velocity which has passed through the minimum clearance portion 16.

Further, the labyrinth seal 10 may be configured so that the fluid flows in the flow path 15 from the radially inner side to the outer side. In this case, the radially outer surface of the first convex portion 11 or the front end (end side) of the radially outer surface of the first convex portion 11 and the radially inner surface of the second convex portion 12, (End side), the minimum clearance portion 16 is formed.

Next, the specific configurations of the embodiments shown in Figs. 4 and 5 will be described, respectively.

As shown in Fig. 4, in one embodiment, the seal end 12a is formed at the tip of the second convex portion 12 of the labyrinth seal 10. The minimum clearance portion 16 is formed between the inner surface in the radial direction of the first convex portion 11 and the seal end 12a of the second convex portion 12.

As a specific example, the inner surface in the radial direction of the first convex portion 11 is formed along the axial direction. The radially outer surface of the first convex portion 11 is formed to be inclined with respect to the axial direction. At this time, the radially outward surface of the first convex portion 11 may be inclined in the direction away from the inlet side of the vane roller 32 in the axial direction as it goes inward from the radial direction. The width of the first convex portion 11 in the radial direction is larger at the distal end portion on the side of the stop member 46 than the base portion on the back surface 35 side of the vane wheel 32. [ The first convex portion 11 may be provided with an R portion at a corner portion in the radial direction, or the corner portion may be chamfered in a tapered shape. Thus, in the case of being made of a material such as an aluminum alloy from the viewpoint of weight reduction, durability can be improved.

On the other hand, both the inner and outer surfaces in the radial direction of the second convex portion 12 are inclined with respect to the axial direction, and these surfaces are parallel to each other. At this time, the radially inner side surface and the outer side surface of the second convex portion 12 are inclined in the direction away from the inlet side of the impeller 32 in the axial direction from the radially outer side toward the inner side . Also, the second convex portion 12 may be provided with an R portion at an edge portion in the radial direction, or the edge portion may be chamfered in a tapered shape.

The seal end portion 12a is formed in the second convex portion 12 on the side of the stop member 46. The seal portion 12 is formed on the downstream side of the minimum clearance portion 16, The wall surface of the stop member 46 (the wall surface of the second convex portion 12) is away from the flow of the fluid. Therefore, it is possible to effectively suppress the situation in which the fluid that has passed through the minimum clearance portion 16 and is conveyed with a fluid having a high flow velocity is conveyed to the blade 32 side. Therefore, the amount of heat input from the fluid passing through the labyrinth seal 10 to the impeller 32 can be effectively reduced, and the temperature rise of the impeller 32 can be further suppressed.

In this case, the inner surface in the radial direction of the first convex portion 11 forms a sealing surface extending along the axial direction of the centrifugal compressor (for example, the direction of the rotation axis O shown in Fig. 1). The second convex portion 12 is formed so as to protrude from the stop member 46 toward the outer side in the radial direction on the back surface 35 side of the vane car 32 as well.

According to the above configuration, the clearance width direction of the minimum clearance portion 16 follows the radial direction. Therefore, even if the vane roller 32 deviates in the axial direction, the clearance width of the minimum clearance portion 16 is not affected well . Therefore, it is possible to suppress the deterioration of the seal performance due to the displacement of the vane roller 32 in the axial direction.

As shown in Fig. 7, in another embodiment, a seal end 11a is formed at the tip of the first convex portion 11 of the labyrinth seal 10. The minimum clearance portion 16 is formed between the seal end 11a of the first convex portion 11 and a radially outer surface of the second convex portion 12.

As a specific configuration, the inner surface in the radial direction of the first convex portion 11 and the outer surface in the radial direction of the first convex portion 11 are formed to be inclined with respect to the axial direction. At this time, the inner surface in the radial direction of the first convex portion 11 and the outer surface in the radial direction of the first convex portion 11, as viewed from the radially outer side toward the inner side, Or may be inclined in a direction away from the entrance side of the car 32. The inclination angle of the inner surface in the radial direction of the first convex portion 11 and the outer surface in the radial direction of the first convex portion 11 may be different from each other. In this case, the distal end of the first convex portion 11 on the side of the stop member 46 is wider in the radial direction than the base portion on the rear surface 35 side of the vane wheel 32. [ Further, the first convex portion 11 may be provided with R at a corner portion in the radial direction, or the corner portion may be chamfered in a tapered shape. Thus, in the case of being made of a material such as an aluminum alloy from the viewpoint of weight reduction, durability can be improved.

On the other hand, both the inner and outer surfaces in the radial direction of the second convex portion 12 are formed along the axial direction, and these surfaces are parallel to each other. Also, the second convex portion 12 may be provided with an R portion at an edge portion in the radial direction, or the edge portion may be chamfered in a tapered shape.

The minimum distance between the seal end 11a of the first convex portion 11 on the side of the vane wheel 32 and the radially outer surface of the second convex portion 12 of the stationary member 46 The fluid that has passed through the clearance portion 16 can be directed toward the back surface 35 of the vane wheel 32. [ Thereby, the amount of heat input from the fluid passing through the labyrinth seal 10 to the impeller 32 can be reduced, and the temperature rise of the impeller 32 can be suppressed.

In this case, the seal end 11a is formed at the tip end of the first convex portion 11, and the minimum clearance portion 16 is formed at the seal end 11a of the first convex portion 11 and the second convex portion 11b 12 in the radial direction.

According to the above configuration, the clearance width direction of the minimum clearance portion 16 follows the radial direction. Therefore, even if the vane roller 32 deviates in the axial direction, the clearance width of the minimum clearance portion 16 is not affected well . Therefore, it is possible to suppress the deterioration of the seal performance due to the displacement of the vane roller 32 in the axial direction.

As described above, according to the labyrinth seal 10 according to at least one embodiment of the present invention, the amount of heat input from the fluid passing through the labyrinth seal 10 to the impeller 32 is reduced, 32 can be suppressed. Therefore, it is possible to suppress the deterioration of the creep life due to the high temperature of the vane wheel 32. [

According to the centrifugal compressor according to at least one embodiment of the present invention, the amount of heat input from the fluid passing through the labyrinth seal 10 to the impeller 32 is reduced, and the temperature rise of the impeller 32 is suppressed . Therefore, it is possible to suppress the deterioration of the creep life due to the high temperature of the vane pulley 32, and it is possible to realize the high-pressure spark of the centrifugal compressor.

Further, according to the supercharger 1 according to at least one embodiment of the present invention, by reducing the amount of heat input from the fluid passing through the labyrinth seal 10 to the impeller 32, the centrifugal compressor can realize a high- , The performance of the supercharger 1 can be improved.

The present invention is not limited to the above-described embodiment, but includes a form in which a modification is added to the above-described embodiment, and a form in which these forms are appropriately combined.

The labyrinth seal 10 is applied to the centrifugal compressor 3 in the turbocharger 1 but the application of the labyrinth seal 10 is not limited to the centrifugal compressor 3 of the turbocharger, But may be used for other centrifugal compressors.

In the above embodiment, the supercharger 1 has been described as an application of the centrifugal compressor. However, the application of the centrifugal compressor according to the present embodiment is not limited to this.

For example, an expression that represents a relative or absolute arrangement such as "radial", "in either direction", "along any direction", "parallel", "orthogonal", "center", "concentric" Not only strictly indicate such an arrangement but also a state of being displaced relative to an angle or a distance to the extent that the tolerance or the same function is obtained.

For example, expressions indicating that objects such as " same ", " equivalent ", and " homogeneous " are equivalent represent not only strictly equivalent states, but also tolerances, .

For example, the expression indicating a shape such as a square shape or a cylinder shape not only shows a shape such as a square shape or a cylindrical shape in a geometrically strict sense, but also includes a concave portion and a chamfer portion in a range in which the same effect can be obtained And the like.

On the other hand, the expression " comprises, " " including, " or " having " an element is not an exclusive expression excluding the presence of other elements.

1: supercharger
2: Turbine
3: Centrifugal compressor
4: Bearing stand
5: Rotor
10: Labyrinth seal
11: first convex portion
11a, 12a: end of the seal
12: second convex portion
15: Euro
16: Minimum clearance part
21: Turbine casing
24: rotor
31: Compressor casing
32: Wing car
33: Hub
35: back face
41: Thrust bearing
42: Radial bearing
43: Radial bearing
44: Lubricant supply passage
46: stop member
50: labyrinth seal
51: Euro
52: first convex portion
53: second convex portion
54: minimum clearance part
55: Expansion area
56: Wall
O:

Claims (7)

CLAIMS 1. A labyrinth seal used in a centrifugal compressor having a bladed wheel and a stationary member formed on the back side of the bladed wheel,
A plurality of first convex portions each formed along the circumferential direction on the back surface of the vane;
And a plurality of second convex portions formed along the circumferential direction on the stop member so that the front end portion enters between the adjacent first convex portions,
A flow path on a labyrinth having a plurality of minimum clearance portions formed between the first convex portion and the second convex portion is formed between the back surface of the vane wheel and the stop member,
Wherein the stop member is positioned on the upstream side of the minimum clearance portion in the flow direction of the flow passing through the minimum clearance portion formed between the first convex portion and the second convex portion, And the rear surface of the light-
Wherein the labyrinth seal is configured to seal the flow radially inward between the back surface of the vane car and the stop member,
Wherein the minimum clearance portion is formed between a tip end of the first convex portion and the second convex portion or between a tip end of the first convex portion and a tip end of the second convex portion. The method according to claim 1,
And a sealing end is formed at the tip of the second convex portion,
Wherein the minimum clearance portion is formed between the seal end of the first convex portion and the seal end of the second convex portion. 3. The method of claim 2,
Wherein the first convex portion forms a sealing surface extending along the axial direction of the centrifugal compressor,
And the second convex portion is formed so as to protrude from the stationary member toward the outer side in the radial direction as well as the back side of the vane car. The method according to claim 1,
A seal end is formed at the tip of the first convex portion,
Wherein the minimum clearance portion is formed between the seal end of the first convex portion and the second convex portion. 5. The method of claim 4,
The radially outward surface of the second convex portion forms a sealing surface extending along the axial direction of the centrifugal compressor,
Wherein the first convex portion is formed so as to protrude from the back surface of the vane car toward the stationary member side and also to the inside in the radial direction. A wing car in which the fluid flows in the radial direction,
A stationary member formed on the back side of the vane car,
The centrifugal compressor according to any one of claims 1 to 5, further comprising a labyrinth seal formed between the back surface of the vane wheel and the stop member. A centrifugal compressor according to claim 6;
And a turbine driven by the exhaust gas of the internal combustion engine to drive the centrifugal compressor.

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