COMPRESSOR AND SUPERCHARGER

Abstract

 An object of the present invention is to provide a compressor and a turbocharger whereby it is possible to suppress breakage of a bolt fastening a frame adjacent to a scroll-chamber frame and the scroll-chamber frame effectively and to join the frames stably. A compressor 10 includes: an impeller 14 for compressing air; an air-guide cylinder 16 for housing the impeller 14 and guiding the air; a scroll-chamber frame 20 disposed adjacent to the air-guide cylinder16, the scroll-chamber frame 20 forming a scroll chamber 18 for guiding the air having passed through the air-guide cylinder 16 to outside; a frame (22, 40) disposed adjacent to the scroll-chamber frame 20; a bolt (25, 48) for fastening the scroll-chamber frame 20 and the frame (22, 40); and a spacer 28 disposed between a head portion (26, 52) of the bolt (25, 48) and the scroll-chamber frame 20.

Description

TECHNICAL FIELD

[0001] The present invention relates to a compressor and a turbocharger used for an internal combustion engine.

BACKGROUND ART

[0002] A conventionally-used turbocharger for compressing air to be supplied to an internal combustion engine is equipped with a compressor including an impeller for compressing air, an air-guide cylinder for housing the impeller and guiding the air, and a scroll-chamber frame disposed adjacent to the air-guide cylinder, the scroll-chamber frame forming a scroll chamber for guiding the air having passed through the air-guide cylinder to outside.

[0003] The turbocharger described in Patent Document 1 includes a shock-absorbing partition wall disposed between a diffuser of a compressor and a head tank storing lubricant oil for lubricating a journal bearing so as to prevent the head tank from breaking apart to bring about oil leakage when a part of the impeller bursts and scatters outwardly.

Citation List

Patent Literature

[0004] Patent Document 1: JP2001-132465A

SUMMARY

Problems to be Solved

[0005] If an impeller breaks apart in a compressor constituting a part of a turbocharger, an impeller fragment may fly off outwardly in the radial direction of the impeller, and may hit the air-guide cylinder and a frame around the air-guide cylinder, for instance. If the impeller fragment hits the air-guide cylinder or a frame around the air-guide cylinder, for instance, there is a risk of generation of tensile stress in a bolt for fastening a scroll-chamber frame adjacent to the air-guide cylinder and a frame adjacent to the scroll-chamber frame, which may break the bolt.

[0006] In this regard, although Patent Document 1 describes a configuration for preventing breakage of a lubricant-oil head tank upon scatter of an impeller described above, it does not disclose breakage of the bolt due to scatter of the impeller or a solution thereto.

[0007] An object of some embodiments of the present invention is to provide a compressor and a turbocharger whereby it is possible to suppress breakage of a bolt that fastens a frame adjacent to a scroll-chamber frame and the scroll-chamber frame effectively, and to achieve a stable joint state between the frames.

Solution to the Problems

[0008] 

(1) A compressor according to some embodiments of the present invention comprises: an impeller for compressing air; an air-guide cylinder for housing the impeller and guiding the air; a scroll-chamber frame disposed adjacent to the air-guide cylinder, the scroll-chamber frame forming a scroll chamber for guiding the air having passed through the air-guide cylinder to outside; a first frame disposed adjacent to the scroll-chamber frame; a first bolt for fastening the scroll-chamber frame and the first frame; and a spacer disposed between a head portion of the first bolt and the scroll-chamber frame.
If an impeller breaks apart in a compressor, an impeller fragment may fly off outwardly in the radial direction of the impeller, and hit the air-guide cylinder or a frame around the air-guide cylinder, for instance. If the impeller fragment hits the air-guide cylinder or the frame around the air-guide cylinder, for instance, there is a risk of generation of tensile stress in the first bolt for fastening a scroll-chamber frame adjacent to the air-guide cylinder and the first frame adjacent to the scroll-chamber frame, which may break the first bolt.
In this regard, with the compressor according to the above (1), since the spacer is disposed between the head portion of the first bolt and the scroll-chamber frame, it is possible to fasten the scroll-chamber frame and the first frame using the first bolt with a shank portion having a large length (shank length) as compared to a case where the spacer is not provided. Thus, as compared to a case where the spacer is not provided, it is possible to secure a large amount of extension to which the first bolt can extend without breaking when tensile load in the axial direction is applied to the first bolt. In this way, even if tensile stress caused by breakage of the impeller is generated on the first bolt fastening the scroll-chamber frame and the first frame as described above, it is possible to suppress breakage of the first bolt effectively. Specifically, it is possible to achieve a stable joint state between the scroll-chamber frame and the first frame.
Further, to produce the compressor described in the above (1), it is only required to add a spacer and replace the first bolt for an existing compressor, and it is unnecessary to renew the entire configuration. That is, the compressor according to the above (1) has another merit from the perspective of manufacturability.
Further, "the first frame" of the compressor described in (1) is intended to include at least a silencer frame or a bearing frame described in the following detailed description. Still further, in a case where the first bolt is a stud bolt in the compressor described in the above (1), the head portion of the first bolt refers to a nut used for the stud bolt.

(2) In some embodiments, in the compressor described in the above (1), the spacer is formed in a sleeve shape and disposed so as to surround a shank portion of the first bolt. An inside diameter of the spacer is smaller than a head diameter of the first bolt.
With the compressor described in the above (2), it is possible to support the head portion of the first bolt uniformly with the spacer having a sleeve shape disposed so as to surround the shank portion of the first bolt, which makes it possible to suppress breakage of the first bolt effectively even if tensile stress is generated on the first bolt due to breakage of the impeller as described above. Thus, it is possible to achieve a stable joint state between the scroll-chamber frame and the first frame adjacent to the scroll chamber.

(3) In some embodiments, in the compressor described in the above (1) or (2), a dimension of the spacer in an axial direction of the first bolt is larger than a dimension of the spacer in a radial direction of the first bolt.
As in the compressor described in the above (3), using the spacer configured suitable to increase the length of the shank portion of the first bolt makes it possible to easily secure a large amount of extension to which the first bolt can extend without breaking when tensile load in the axial direction is applied to the first bolt.
In this way, even if tensile stress caused by breakage of the impeller is generated on the first bolt fastening the scroll-chamber frame and the first frame as described above, it is possible to suppress breakage of the first bolt effectively. Thus, it is possible to achieve a stable joint state between the scroll-chamber frame and the first frame adjacent to the scroll-chamber frame.

(4) In some embodiments, the above compressor described in any one of the above (1) to (3) further comprises a silencer for reducing noise generated by the compressor, and the first frame is a frame of the silencer.
With the compressor described in the above (4), even if tensile stress caused by breakage of the impeller is generated on the first bolt fastening the scroll-chamber frame and the frame of the silencer, it is possible to suppress breakage of the first bolt effectively. As a result, it is possible to suppress detachment of the silencer from the compressor effectively.

(5) In some embodiments, the above compressor described in any one of the above (1) to (4) further comprises a second frame disposed adjacent to the scroll-chamber frame; a second bolt for fastening the scroll-chamber frame and the second frame; and a clamp configured to nip the scroll-chamber frame and the second frame.
If an impeller breaks apart in a compressor, an impeller fragment may fly apart outwardly in the radial direction of the impeller, and hit the air-guide cylinder or the scroll-chamber frame. If the impeller fragment hits the air-guide cylinder or the scroll-chamber frame, there is a risk of generation of tensile stress in the second bolt for fastening the scroll-chamber frame and the second frame adjacent to the scroll-chamber frame, which may break the second bolt.
In this regard, according to the compressor described in the above (5), with the clamp configured to nip the scroll-chamber frame and the second frame, it is possible to suppress generation of tensile stress in the second bolt and to suppress breakage of the second bolt effectively. Thus, it is possible to achieve a stable joint state between the scroll-chamber frame and the second frame adjacent to the scroll-chamber frame.
Further, "the second frame" of the compressor described in the above (5) is intended to include at least a silencer frame or a bearing frame described in the detailed description below.

(6) In some embodiments, in the compressor described in the above (5), the second frame is a bearing frame in which a bearing part for pivotally supporting a rotation shaft of the impeller is disposed.
With the compressor described in the above (6), even if tensile stress caused by breakage of the impeller is generated on the second bolt fastening the scroll-chamber frame and the bearing frame, it is possible to suppress breakage of the second bolt effectively. As a result, it is possible to achieve a stable joint state between the scroll-chamber frame and the bearing frame.

(7) In some embodiments, in the compressor described in the above (6), the scroll-chamber frame includes: a scroll-chamber forming portion forming the scroll chamber; and a flange portion disposed so as to extend outwardly in a radial direction of the impeller from the scroll-chamber forming portion to join the scroll-chamber frame and the bearing frame. The second bolt fastens the flange portion and the bearing frame, and the clamp is configured to nip the flange portion and the bearing frame.
In a configuration such that the bearing frame is joined with the flange portion extending outwardly from the scroll-chamber forming portion in the radial direction of the impeller, it may be difficult to secure a space between the flange portion and the scroll-chamber forming portion, and it may be difficult to provide a spacer between the head portion of the second bolt and the scroll-chamber frame to prevent breakage of the second bolt.
Even in such a case, according to the compressor described in the above (7), with the clamp configured to nip the scroll-chamber frame and the bearing frame, it is possible to suppress generation of tensile stress in the second bolt and to suppress breakage of the second bolt effectively. As a result, it is possible to achieve a stable joint state between the scroll-chamber frame and the bearing frame.

(8) In some embodiments, in the compressor described in the above (7), the clamp includes a pressing bolt which applies a pressing force to the bearing frame from an opposite side from the flange portion of the scroll-chamber frame.
In a configuration such that the bearing frame is joined with the flange portion extending outwardly from the scroll-chamber forming portion in the radial direction of the impeller, it may be difficult to secure a space between the flange portion and the scroll-chamber forming portion, and it may be difficult to provide a spacer between the head portion of the second bolt and the scroll-chamber frame to prevent breakage of the second bolt.
Even in such a case, with the pressing bolt for applying a pressing force to the bearing frame from the opposite side from the flange portion of the scroll-chamber frame as in the compressor described in the above (8), it is possible to suppress generation of tensile stress in the second bolt with a simplified configuration and to suppress breakage of the second bolt effectively. As a result, it is possible to achieve a stable joint state between the scroll-chamber frame and the bearing frame with a simplified configuration.

(9) A turbocharger according to some embodiments of the present invention comprises the compressor according to any one of the above (1) to (8).

[0009] With the turbocharger according to some embodiments of the present invention, it is possible to suppress breakage of the first bolt effectively even if tensile stress is generated due to breakage of the impeller.

[0010] Specifically, it is possible to achieve a stable joint state between the scroll-chamber frame and the first frame.

Advantageous Effects

[0011] According to some embodiments of the present invention, it is possible to suppress breakage of a bolt fastening a frame adjacent to a scroll-chamber frame and the scroll-chamber frame effectively, and to achieve a stable joint state between the frames.

BRIEF DESCRIPTION OF DRAWINGS

[0012] 

FIG. 1 is a schematic diagram illustrating an overall configuration of an internal combustion engine system according to some embodiments.

FIG. 2 is a schematic cross-sectional view of a part of a turbocharger according to some embodiments.

FIG. 3 is a schematic cross sectional view of a bolt for fastening a scroll-chamber frame and a silencer frame and its peripheral structure.

FIG. 4 is a diagram illustrating a state where a scroll-chamber frame is deformed and tensile stress is generated on a bolt fastening the scroll-chamber frame and a bearing frame.

FIG. 5 is a view of a flange portion of the scroll-chamber frame and a flange portion of the bearing frame as seen from direction P in FIG. 2.

FIG. 6 is a schematic cross-sectional view for describing a structure of a clamp according to some embodiments.

DETAILED DESCRIPTION

[0013] Embodiments of the present invention will now be described with reference to the accompanying drawings. It is intended, however, that unless particularly specified, dimensions, materials, shapes, relative positions and the like of components described in the embodiments shall be interpreted as illustrative only and not intended to limit the scope of the present invention unless particularly specified.

[0014] FIG. 1 is a schematic diagram illustrating an overall configuration of an internal combustion engine system 100 according to some embodiments.

[0015] The internal combustion engine system 100 illustrated in FIG. 1 includes an internal combustion engine 2, a turbocharger 4 for pressurizing intake air sucked into the internal combustion engine 2, and a generator 8 driven by a turbine 6 of the turbocharger 4.

[0016] The turbocharger 4 illustrated in FIG. 1 includes a compressor 10 of centrifugal type for pressurizing intake air sucked into the internal combustion engine 2, a turbine 6 coupled to the compressor 10 via a rotation shaft 12 and driven by exhaust gas of the internal combustion engine 2, and a silencer 13 for reducing noise that the compressor 10 generates.

[0017] The turbocharger 4 illustrated in FIG 1 is a supercharger of exhaust-turbine drive type, which is called a turbocharger, in which the compressor 10 is driven by the turbine 6 driven by exhaust gas of the internal combustion engine 2. In another embodiment, the turbocharger 4 may be a supercharger of mechanical drive type, which is called a supercharger, in which the compressor 10 is driven by power extracted from an output shaft of the internal combustion engine 2 via a belt or the like. Further, as the internal combustion engine 2, for instance, a diesel engine or a gasoline engine may be suitably selected.

[0018] Next, the specific configuration of the turbocharger 4 will be described below with reference to FIG. 2.

[0019] FIG. 2 is a schematic cross-sectional view of a part of a turbocharger 4 according to some embodiments.

[0020] The compressor 10 illustrated in FIG 2 includes an impeller 14 for compressing air, an air-guide cylinder 16 housing the impeller 14 and guiding air, a scroll-chamber frame 20, and a bearing frame 40. The impeller 14 includes a hub 15 and a plurality of blades 17 disposed around the hub 15. The scroll-chamber frame 20 is disposed adjacent to the air-guide cylinder 16, and includes a scroll-chamber forming portion 19 which forms a scroll chamber 18 for guiding air that has passed through the air-guide cylinder 16 to outside. The bearing frame 40 includes a bearing portion 44 for pivotably supporting a rotation shaft 12 of the impeller 14.

[0021] The silencer 13 includes a silencer frame 22 disposed adjacent to the scroll-chamber frame 20. With regard to the scroll-chamber frame 20 and the silencer frame 22, a flange portion 23 of the scroll-chamber frame 20 and a flange portion 24 of the silencer frame 22 are fastened to each other by a bolt 25. A spacer 28 (see FIG. 3) is disposed between a head portion 26 of the bolt 25 and the scroll-chamber frame 20.

[0022] With regard to the bearing frame 40 and the scroll-chamber frame 20, a flange portion 46 of the bearing frame 40 and a flange portion 29 of the scroll-chamber frame 20 are fastened to each other by a bolt 48.

[0023] If the impeller 14 breaks apart in the compressor 10 constituting a part of the turbocharger 4 illustrated in FIG 2, an impeller fragment may fly apart outwardly in the radial direction of the impeller 14, and may hit the air-guide cylinder 16, the scroll-chamber frame 20, or the like.

[0024] For instance, if the impeller fragment hits an oblique section 30 of the air-guide cylinder 16, the hit causes an inlet 32 of the air-guide cylinder 16 to move toward the silencer 13 in the direction S of the arrow (see FIG. 3) and hit an outlet 43 of the silencer frame 22. As a result, the flange portion 24 of the silencer frame 22 tries to move away from the flange portion 23 of the scroll-chamber frame 20, which leads to generation of tensile stress on the bolt 25.

[0025] Even if tensile stress is generated on the bolt 25 as described above, the compressor 10 and the turbocharger 4 are configured such that the spacer 28 is disposed between the head portion 26 of the bolt 25 and the scroll-chamber frame 20, which makes it possible to fasten the scroll-chamber frame 20 and the silencer frame 22 using the bolt 25 with a shank portion 31 (see FIG. 3) having a large length (shank length) as compared to a case where the spacer 28 is not provided. Thus, as compared to a case where the spacer 28 is not provided, it is possible to secure a large amount of extension to which the bolt 25 can extend without breaking when receiving tensile load in the axial direction. In this way, even if tensile stress caused by breakage of the impeller 14 is generated on the bolt 25 fastening the scroll-chamber frame 20 and the silencer frame 22, it is possible to suppress breakage of the bolt 25 effectively. As a result, it is possible to join the scroll-chamber frame 20 and the silencer frame 22 stably, and to suppress detachment of the silencer 13 from the turbocharger 4 or the compressor 10 effectively.

[0026] The spacer 28 illustrated in FIG. 3 is formed in a sleeve shape and disposed so as to surround the shank portion 31 of the bolt 25, and the inside diameter d₁ of the spacer 28 is smaller than the diameter d₂ of the head portion 26 of the bolt 25. Thus, it is possible to support the head portion 26 of the bolt 25 uniformly with the spacer 28, which makes it possible to suppress breakage of the bolt 25 effectively if tensile stress is generated on the bolt 25 due to breakage of the impeller 14 as described above.

[0027] Further, the dimension d₃ of the spacer 28 in the axial direction of the bolt 25 illustrated in FIG. 3 is greater than the dimension d₄ of the spacer 28 in the radial direction of the spacer 28. Thus, with the spacer 28 configured suitable to increase the length of the shank portion 31 of the bolt 25, it is possible to easily secure a large amount of extension to which the bolt 25 can extend without breaking when receiving tensile load in the axial direction. In this way, even if tensile stress caused by breakage of the impeller 14 is generated on the bolt 25 fastening the scroll-chamber frame 20 and the silencer frame 22, it is possible to suppress breakage of the bolt 25 effectively.

[0028] In FIG 3, an example in which tensile stress is generated due to breakage of the impeller 14 on the bolt 25 fastening the scroll-chamber frame 20 and the silencer frame 22 is described. On the other hand, tensile stress may be generated due to breakage of the impeller 14 on the bolt 48 fastening the scroll-chamber frame 20 and the bearing frame 40.

[0029] For instance, if the impeller fragment enters a diffuser portion 50 illustrated in FIG. 2 and gets stuck in the diffuser portion 50, the impeller fragment presses the diffuser portion 50 to expand in the axial direction of the impeller 14. As a result, the scroll-chamber frame 20 and the bearing frame receive a force in a direction away from each other, and thus the scroll-chamber frame 20 deforms as illustrated in FIG. 4 and tensile stress is generated on the bolt 48.

[0030] To prevent breakage of the bolt 48 due to the above tensile stress, in some embodiments, the spacer 28 described with reference to FIG 3 may be disposed between the head portion 52 of the bolt 48 and the scroll-chamber frame 20 to make the shank portion 53 of the bolt 48 longer than that illustrated in FIG. 4. However, as illustrated in FIG. 2, the flange portion 29 of the scroll-chamber frame 20 is disposed so as to extend outwardly from the scroll-chamber forming portion 19 in the radial direction of the impeller 14. Thus, it is difficult to secure a space between the flange portion 29 and the scroll-chamber forming portion 19, and it may be difficult to provide a spacer between the head portion 52 of the bolt 48 and the scroll-chamber frame 20 to prevent breakage of the bolt 48.

[0031] In view of this, the turbocharger 4 and the compressor 10 illustrated in FIG. 2 includes a clamp 54 configured to nip the scroll-chamber frame 20 and the bearing frame 40 as illustrated in FIGs. 5 and 6. FIG. 5 is a view of the flange portion 29 of the scroll-chamber frame 20 and the flange portion 46 of the bearing frame 40 as seen from direction P in FIG 2, illustrating the arrangement of the bolt 48 and the clamp 54. FIG. 6 is a schematic cross-sectional view for describing a structure of the clamp 54.

[0032] As described above, using the clamp 54 configured to nip the flange portion 29 of the scroll-chamber frame 20 and the flange portion 46 of the bearing frame 40 makes it possible to suppress generation of tensile stress on the bolt 48 and to suppress breakage of the bolt 48 effectively, even for a configuration such that it is difficult to secure a sufficient space for providing the above described spacer between the flange portion 29 and the scroll-chamber forming portion 19. As a result, it is possible to join the scroll-chamber frame 20 and the bearing frame 40 stably.

[0033] The clamp 54 illustrated in FIGs. 5 and 6 includes a pressing bolt 56 that applies a pressing force to the bearing frame 40 from the opposite side from the flange portion 29 of the scroll-chamber frame 20. In this way, even in a case where it is difficult to provide a spacer between the head portion 52 of the bolt 48 and the scroll-chamber frame 20 as described above in order to prevent breakage of the bolt 48, it is possible to suppress generation of tensile stress on the bolt 48 with a simplified configuration, and to suppress breakage of the bolt 48 effectively. As a result, it is possible to join the scroll-chamber frame 20 and the bearing frame 40 stably with a simplified configuration. Further, in another embodiment, a pressing bolt that applies a pressing force to the flange portion 29 of the scroll-chamber frame 20 from the opposite side from the bearing frame 40 may be used.

[0034] In the embodiment described with reference to FIG. 6, the clamp 54 is configured to nip the scroll-chamber frame 20 and the bearing frame 40. In another embodiment, a clamp configured to nip the scroll-chamber frame 20 and the silencer frame 22 may be used. In this way, it is possible to join the scroll-chamber frame 20 and the silencer frame 22 stably.

Description of Reference Numeral

[0035] 

2

Internal combustion engine

4

Turbocharger

6

Turbine

8

Generator

10

Compressor

12

Rotation shaft

13

Silencer

14

Impeller

16

Air-guide cylinder

17

Blade

18

Scroll chamber

19

Scroll-chamber forming portion

20

Scroll-chamber frame

22

Silencer frame

23, 24, 29, 46

Flange portion

25, 48

Bolt

26, 52

Head portion

28

Spacer

30

Oblique section

31

Shank portion

32

Inlet

40

Bearing frame

43

Outlet

44

Bearing portion

50

Diffuser portion

54

Clamp

56

Pressing bolt

100

Internal combustion engine system

d1

Inside diameter

d2

Diameter

d3, d4

Dimension

Claims

1. A compressor comprising:

an impeller for compressing air;

an air-guide cylinder for housing the impeller and guiding the air;

a scroll-chamber frame disposed adjacent to the air-guide cylinder, the scroll-chamber frame forming a scroll chamber for guiding the air having passed through the air-guide cylinder to outside;

a first frame disposed adjacent to the scroll-chamber frame;

a first bolt for fastening the scroll-chamber frame and the first frame; and

a spacer disposed between a head portion of the first bolt and the scroll-chamber frame.

2. The compressor according to claim 1,
wherein the spacer is formed in a sleeve shape and disposed so as to surround a shank portion of the first bolt, and
wherein an inside diameter of the spacer is smaller than a head diameter of the first bolt.

3. The compressor according to claim 1 or 2,
wherein a dimension of the spacer in an axial direction of the first bolt is larger than a dimension of the spacer in a radial direction of the first bolt.

4. The compressor according to any one of claims 1 to 3, further comprising

a silencer for reducing noise generated by the compressor,

wherein the first frame is a frame of the silencer.

5. The compressor according to any one of claims 1 to 4, further comprising:

a second frame disposed adjacent to the scroll-chamber frame;

a second bolt for fastening the scroll-chamber frame and the second frame; and

a clamp configured to nip the scroll-chamber frame and the second frame.

6. The compressor according to claim 5,
wherein the second frame is a bearing frame in which a bearing part for pivotally supporting a rotation shaft of the impeller is disposed.

7. The compressor according to claim 6,
wherein the scroll-chamber frame includes:

a scroll-chamber forming portion forming the scroll chamber; and

a flange portion disposed so as to extend outwardly in a radial direction of the impeller from the scroll-chamber forming portion to join the scroll-chamber frame and the bearing frame,

wherein the second bolt fastens the flange portion and the bearing frame, and
wherein the clamp is configured to nip the flange portion and the bearing frame.

8. The compressor according to claim 7,
wherein the clamp includes a pressing bolt which applies a pressing force to the bearing frame from an opposite side from the flange portion of the scroll-chamber frame.

9. A turbocharger comprising the compressor according to any one of claims 1 to 8.

Drawing