Shroud

Abstract

To provide a shroud capable of suppressing leakage flow while allowing an outer peripheral end part of a blade to work.SOLUTION: A shroud to which a fan body is attached, includes a plurality of ribs extending along exhaust air from blades of a fan body and arrayed in a circumferential direction, where an intermediate ring extending in the circumferential direction is attached to the intermediate part of the blade in a radial direction, an opening through which the exhaust air passes is formed between adjacent ribs, the ribs and the openings are arranged at positions axially opposite the blades. The intermediate ring extending in the circumferential direction is attached to the intermediate part of the blade in the radial direction, and the ribs and the openings are arranged at positions axially opposite the outer peripheral wing of the blade provided radially outward of the intermediate ring.SELECTED DRAWING: Figure 3A

Description

Technical Field

[0001] The present invention relates to a shroud to which a fan body is attached.

Background Art

[0002] There is known a technique of providing a ring on the outermost periphery of the blades of a fan body and suppressing leakage flow by a labyrinth structure formed on the outer peripheral side of the ring (see, for example, Patent Document 1).

[0003] On the other hand, Patent Document 2 discloses a fan in which an intermediate ring is provided at an intermediate portion of the blades. According to such a fan, work (exhaust air) can be performed up to the outer peripheral blades (outer peripheral ends) of the blades located on the outer peripheral side of the intermediate ring.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, the technique using the labyrinth structure disclosed in Patent Document 1 cannot be directly applied to a fan that can perform work up to the outer peripheral ends of the blades, as disclosed in Patent Document 2, for example.

[0006] The present invention has been made to solve the above problems, and an object thereof is to provide a shroud that can suppress leakage flow while performing work up to the outer peripheral ends of the blades.

Means for Solving the Problems

[0007] To solve the above problems, one aspect of the present invention is A shroud to which a fan body is attached, extends along the exhaust air flow by the blades of the fan body and includes a plurality of ribs arranged in the circumferential direction, An intermediate ring extending in the circumferential direction is attached to the middle part of the blade in the radial direction, An opening through which the exhaust air passes is provided between the adjacent ribs, The ribs and the openings are arranged at positions axially opposed to the blades, providing a shroud.

Advantages of the Invention

[0008] According to this invention, while causing work to be done on the outer peripheral blades, leakage flow can be suppressed.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 3A

Figure 3B

Figure 4

Figure 4A

Figure 5

Figure 6

Figure 7

Figure 8

Best Mode for Carrying Out the Invention

[0010] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0011] FIG. 1 is a perspective view of a fan device to which the shroud of this embodiment is applied, viewed from the exhaust side, FIG. 2 is a perspective view of the fan device to which the shroud of this embodiment is applied, viewed from the intake side, FIG. 3 is a partially enlarged view of FIG. 1, FIG. 3A is a perspective view of the vicinity of the rib of the fan device, viewed from the exhaust side, FIG. 3B is a perspective view of the shroud, viewed from the exhaust side, FIG. 4 is a partially enlarged view of FIG. 2, FIG. 4A is a view showing the shroud in FIG. 4, FIG. 5 is a perspective view of the fan member, viewed from the exhaust side, and FIG. 6 is a perspective view of the fan member, viewed from the intake side.

[0012] As shown in FIGS. 1 and 2, the fan device 1 includes a fan main body having a motor M and a fan member 10 driven by the motor M around a rotation axis, and a shroud 20 to which the fan main body is attached.

[0013] In the present disclosure, the axial direction corresponds to the direction of the rotation axis of the fan member 10, the circumferential direction corresponds to the direction around the rotation axis of the fan member 10, and the radial direction corresponds to the direction orthogonal to the rotation axis of the fan member 10, respectively.

[0014] A central portion 20A (FIG. 1) to which the motor M is attached is provided at the central portion of the shroud 20, and an outer peripheral portion 20B (FIGS. 1 and 2) forming a substantially rectangular outer shape of the shroud 20 is provided on the outer peripheral side of the central portion 20A. A ring-shaped opening 30 (FIG. 2) is formed in the gap between the central portion 20A and the outer peripheral portion 20B, and the fan member 10 is accommodated in the opening 30. The central portion 20A is supported by a bridging portion 20C (FIGS. 1 and 2) extending from the outer peripheral portion 20B.

[0015] As shown in FIGS. 3 to 4A, the shroud 20 includes a plurality of ribs 21 that extend along the exhaust air from the blades 12 of the fan member 10 and are arranged in the circumferential direction. Further, an opening 25 (FIGS. 3 and 4A) through which the exhaust air passes is formed between adjacent ribs 21. This opening 25 constitutes the outer peripheral end portion of the ring-shaped opening 30. The radially outer end of the opening 25 is formed on the shroud 20 and is defined by the outer peripheral side wall surface 23 that extends in the circumferential direction.

[0016] The radially inner tip portions of the ribs 21 are connected to each other by a ring-shaped connecting portion 22 that extends in the circumferential direction. Thereby, the strength of the ribs 21 can be ensured.

[0017] As shown in FIGS. 3 to 4A, the ribs 21 and the opening 25 are arranged at positions axially opposed to the outer peripheral wing 12a provided radially outside the intermediate ring 13.

[0018] As shown in FIGS. 5 and 6, the fan member 10 has a boss portion 11 attached to a rotor (not shown) of the motor M, and a plurality (seven in this embodiment) of blades 12 extending radially outward from the boss portion 11. Further, an intermediate ring 13 extending in the circumferential direction is attached to the intermediate portion of the blade 12 in the radial direction. By connecting the plurality of blades 12 to each other by the intermediate ring 13, the vibration of the blades 12 is suppressed.

[0019] On the blade 12, an outer peripheral wing 12a that protrudes radially outward from the intermediate ring 13 is provided radially outside the intermediate ring 13. Further, the above-described outer peripheral side wall surface 23 is provided on the radially outer side of the outer peripheral wing 12a. The outer peripheral side wall surface 23 is located at a position overlapping the radially leading end portion of the outer peripheral wing 12a in the axial direction. Note that a tapered wall surface 23a connected to the outer peripheral side wall surface 23 is formed on the intake side of the outer peripheral side wall surface 23 in the shroud 20.

[0020] Next, the function of the rib 21 will be described.

[0021] FIG. 7 is a perspective view showing the positional relationship between the rib and the outer peripheral wing, and FIG. 8 is a cross-sectional view of the vicinity of the outer peripheral wing in a plane passing through the rotation axis of the fan member and the rib.

[0022] As shown in FIGS. 7 and 8, a gap (tip clearance) is formed between the radially outer end of the outer peripheral wing 12a and the outer peripheral side wall surface 23. For this reason, a leakage flow in the direction indicated by arrow 53 in FIG. 8 occurs. However, according to the present embodiment, not only the exhaust air 51 (FIG. 8) generated by the blade 12 radially inside the intermediate ring 13 but also the exhaust air 52 (FIG. 8) generated by the outer peripheral wing 12a and passing through the opening 25 occurs. Therefore, the leakage flow can be suppressed by the exhaust air 52 in the direction opposite to the direction of the leakage flow indicated by arrow 53.

[0023] Also, in the present embodiment, since the rib 21 is extended in the axial direction (the left-right direction in FIG. 8) which is the direction of the exhaust air 52 and the opening 25 is formed between adjacent ribs 21, the exhaust efficiency can be maintained without being inhibited by the rib 21. Note that the exhaust efficiency can be maximized by inclining the extending direction of the rib 21 from the axial direction in accordance with the direction of the exhaust air 52 generated by the blade angle of attack of the outer peripheral wing 12a.

[0024] Also, the rib 21 has an effect of blocking the leakage flow. That is, while the angle of the exhaust air 52 generated by the outer peripheral wing 12a is constant, the leakage flow is generated such that the air flow from all directions enters between the radially outer end of the outer peripheral wing 12a and the outer peripheral side wall surface 23. For this reason, the rib 21 provided in accordance with the angle of the exhaust air 52 exhibits a function of inhibiting only the leakage flow without reducing the air volume of the exhaust air 52. That is, the rib 21 can suppress the leakage flow without reducing the air volume due to the outer peripheral end portion of the blade 12. Further, this brings an effect of suppressing the pressure fluctuation of the shroud ring (near the bell mouth) and can reduce the noise level.

[0025] Note that the intervals between the plurality of ribs 21 may be provided evenly in the circumferential direction, but the ribs 21 can be arranged unevenly in the circumferential direction (see, for example, FIG. 4A). When adopting the uneven arrangement, the frequencies of the noise generated due to the ribs 21 can be dispersed. As a result, the peak value of the noise generated at a specific frequency can be suppressed, and the substantial noise level perceived as the sound quality can be reduced.

[0026] As described above, according to the present embodiment, since the rib 21 extends in the direction of the exhaust air 52 and the opening 25 is formed between the adjacent ribs 21, the leakage flow can be suppressed while causing the work to reach the outer peripheral end portion of the blade 12. Further, by suppressing the leakage flow, low noise can be achieved.

[0027] Regarding the above embodiments of the present invention, the following additional remarks are further disclosed.

[0028] [Appendix 1] A shroud (20) to which the fan body (10, M) is attached, extending along the exhaust air by the blade (12) of the fan body and including a plurality of ribs (21) arranged in the circumferential direction, an intermediate ring (13) extending in the circumferential direction is attached to the intermediate portion of the blade in the radial direction, an opening (25) through which the exhaust air passes is formed between the adjacent ribs, the shroud in which the ribs and the opening are arranged at positions axially opposed to the blade.

[0029] According to the configuration described in Appendix 1, since the ribs extend in the direction of the exhaust air and the opening is formed between the adjacent ribs, the leakage flow can be suppressed without inhibiting the exhaust efficiency by the ribs.

[0030] [Appendix 2] The shroud according to Appendix 1, wherein the ribs and the opening are arranged at positions axially opposed to the outer peripheral wing (12a) of the blade provided radially outside the intermediate ring.

[0031] According to the configuration described in Supplementary Note 2, since the rib and the opening are arranged at positions axially opposed to the outer peripheral wing of the blade, leakage flow can be suppressed without inhibiting the air blowing by the outer peripheral wing.

[0032] [Supplementary Note 3] The shroud according to Supplementary Note 1, wherein an outer peripheral side wall surface (23) extending in the circumferential direction is formed on the radially outer side of the blade at a position overlapping the radially leading end portion of the blade in the axial direction.

[0033] According to the configuration described in Supplementary Note 3, the leakage flow through the gap formed between the radially leading end portion of the blade and the outer peripheral side wall surface can be suppressed by the rib.

[0034] [Supplementary Note 4] The shroud according to Supplementary Note 1, wherein the radially inner tip portions of the plurality of ribs are connected to each other by a ring-shaped connecting portion (22) extending in the circumferential direction.

[0035] According to the configuration described in Supplementary Note 4, the strength of the rib can be ensured by the ring-shaped connecting portion.

[0036] [Supplementary Note 5] The shroud according to Supplementary Note 1, wherein the interval in the circumferential direction of the rib is set unevenly.

[0037] According to the configuration described in Supplementary Note 5, by dispersing the frequency of the generated noise, the peak value of the noise generated at a specific frequency can be suppressed, and the substantial noise level perceived as the auditory sensation can be reduced.

Explanation of Signs

[0038] 10 Fan member 12 Blade 12a Outer peripheral wing 13 Intermediate ring 20 Shroud 21 Rib 22 Connecting portion 23 Outer peripheral side wall surface 25 openings M motor

Claims

1. A shroud to which a fan body is attached, comprising a plurality of ribs that extend along the exhaust air by the blades of the fan body and are arranged in the circumferential direction, an intermediate ring extending in the circumferential direction is attached to the middle part of the blade in the radial direction, an opening through which the exhaust air passes is formed between the ribs adjacent to each other, the shroud in which the ribs and the opening are arranged at positions axially opposed to the blade.

2. The shroud according to claim 1, wherein the ribs and the opening are arranged at positions axially opposed to the outer peripheral blades of the blade provided radially outside the intermediate ring.

3. The shroud according to claim 1, wherein an outer peripheral side wall surface extending in the circumferential direction is formed on the outer side in the radial direction of the blade at a position overlapping the radial tip of the blade in the axial direction.

4. The shroud according to claim 1, wherein the radially inner tips of the plurality of ribs are connected to each other by a ring-shaped connecting portion extending in the circumferential direction.

5. The shroud according to claim 1, wherein the intervals of the ribs in the circumferential direction are set unevenly.

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