JP2012211577A - Centrifugal blower and air conditioner with the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a centrifugal blower capable of suppressing reduction of fan efficiency caused by a leak flow.SOLUTION: A bell mouth 25 has a bell mouth body 22, a belt 26 wound around an outer circumferential surface 22s of the bell mouth body 22 along the circumferential direction, and a belt-shaped member 28 including a plurality of walls 27 connected to the belt 26. The plurality of walls 27 is arranged at predetermined interval along the circumferential direction of the outer circumferential surface 22s. Each of the walls 27 is erected from at least one of the outer circumferential surface 26s of the belt 26 and the outer circumferential surface 22s of the bell mouth body 22, and is extended along the outer circumferential surface 22s of the bell mouth body 22 from the front F in the axial direction toward the rear R so as to be substantially parallel in the axial direction and in the radial direction of the bell mouth 25.

Description

  The present invention relates to a centrifugal blower and an air conditioner including the same.

  Conventionally, for example, a centrifugal blower is used as a blower of an indoor unit of an air conditioner. In this centrifugal blower, when the fan motor is driven and the impeller rotates, air is sucked into the housing of the indoor unit from the suction port of the indoor unit. The sucked air is guided by the bell mouth to the air inlet of the shroud. Hereinafter, the air flow guided to the air suction port by the bell mouth is referred to as a main flow.

  This mainstream air is sent to the outside in the radial direction by a plurality of blades arranged in the circumferential direction between the hub and the shroud, and most of the air is blown into the room through the blowout port of the indoor unit. The part circulates toward the bell mouth through the space between the outer peripheral surface of the shroud and the housing in the indoor unit, and joins the main stream again through the gap between the bell mouth and the shroud. Hereinafter, the air flow that circulates as described above and merges with the main flow through the gap is referred to as a leakage flow (circulation flow). When a leakage flow in which a part of the main flow branches is generated in this way, the amount of air blown into the room is reduced by that amount, so that the fan efficiency is lowered.

  For example, Patent Literature 1 discloses a centrifugal blower in which a large number of grooves are provided on the outer surface of a bell mouth (fan guide) in order to suppress a decrease in fan efficiency. In this centrifugal blower, the leakage flow that circulates toward the bell mouth through the space between the outer peripheral surface of the shroud and the casing is introduced into the gap between the bell mouth and the shroud through the groove (Patent Document). 1 paragraph numbers 0024 and 0052, see FIGS. 5 and 6). Patent Document 1 describes that since the leakage flow is guided by the groove as described above and becomes a stable flow, it is possible to suppress a decrease in the blowing performance due to the fluctuation of the leakage flow.

JP 2001-3899 A

  By the way, in the centrifugal blower described in Patent Document 1, it is considered that a part of the air in the leakage flow needs to enter the inside of the groove in order for the leakage flow to be guided by the groove to become a stable flow.

  However, since the air flowing around the groove at a high speed easily passes through the vicinity of the groove rather than entering the groove, the effect of guiding the air through the groove is not necessarily sufficient. Therefore, further improvement in fan efficiency is desired in the centrifugal fan.

  Then, this invention is made | formed in view of this point, The place made into the objective is providing the centrifugal air blower which can suppress the fall of the fan efficiency resulting from a leak flow.

  (1) The centrifugal blower of the present invention includes an impeller (23) and a bell mouth (25). The impeller (23) is arranged on the inner surface of the shroud (19) along the circumferential direction of the air suction port (19a), and a shroud (19) having a circular air suction port (19a). A plurality of blades (21). The impeller (23) is fixed to the rotating shaft (13) of the fan motor (11). The bell mouth (25) is disposed in front of the shroud (19) in the axial direction (F) of the rotating shaft (13).

  The bell mouth (25) has a bell mouth main body (22) and a belt-like member (28). The bell mouth body (22) is located at a position where the inner diameter and the outer diameter become smaller from the front (F) in the axial direction toward the rear (R), and at the rear (R) in the axial direction than this part. And a portion inserted into the shroud (19) in a state where a predetermined gap is provided between the peripheral edge (19e) of the air suction port (19a). The belt-shaped member (28) includes a belt portion (26) wound around the outer peripheral surface (22s) of the bell mouth main body (22) along the circumferential direction, and a plurality of wall portions connected to the belt portion (26). Includes (27).

  The plurality of wall portions (27) are arranged at a predetermined interval along the circumferential direction of the outer peripheral surface (22s). Each wall portion (27) stands from at least one of the outer peripheral surface (26s) of the belt portion (26) and the outer peripheral surface (22s) of the bell mouth main body (22). Each of the wall portions (27) extends from the front (F) to the rear (R) in the axial direction so as to be substantially parallel to the axial direction and the radial direction of the bell mouth (25). ) Along the outer peripheral surface (22s).

  In this configuration, since the bell mouth (25) has a plurality of wall portions (27), the wall portion (27) serves as a leakage flow resistance, and the amount of leakage flow can be reduced. Moreover, since the direction of the leakage flow can be made closer to the direction of the main flow, it is possible to suppress the main flow from being disturbed when the leakage flow joins the main flow. Thereby, the fall of fan efficiency can be suppressed. In addition, a noise reduction effect can be expected.

  Further, in this configuration, a bell having a plurality of wall portions (27) can be obtained by simply winding a belt-like member (28) separate from the bell mouth main body (22) around the outer peripheral surface (22s) of the bell mouth main body (22). A mouse (25) can be easily produced. Therefore, the bell mouth (25) can be molded using various materials such as metal and resin. Further, since the belt-like member (28) is a separate member from the bell mouth main body (22), the bell mouth main body (22) and the belt-like member (28) can also be manufactured using different materials. .

  The effect of improving the fan efficiency will be specifically described as follows. That is, the mainstream air guided to the air suction port (19a) of the shroud (19) by the bell mouth (25) is mainly in the axial direction of the rotating shaft (13) in the vicinity of the air suction port (19a). It flows in the direction along. On the other hand, the leakage flow in the conventional centrifugal blower is affected by the air flow in the rotation direction caused by the rotation of the shroud (19) and is directed to the direction inclined from the axial direction of the rotation shaft (13) to the rotation direction. Flowing. In this way, in the vicinity of the air suction port (19a) where the main flow and the leakage flow merge, the directions of the main flow and the leakage flow are greatly different, so when the leakage flow merges with the main flow, the main flow is disturbed by the leakage flow. As a result, fan efficiency is reduced.

  On the other hand, in the configuration of the present invention, the outer peripheral surface of the bell mouth (25) from the front (F) to the rear (R) in the axial direction so that the wall (27) is substantially parallel to the axial direction and the radial direction ( 22s). That is, the air flow path (29) sandwiched between the adjacent wall portions (27) faces in the direction along the axial direction. The air flow path (29) is a space in which both sides and the bottom are surrounded by the adjacent wall portion (27) and the outer peripheral surface (22s) of the bell mouth (25). The inlet and outlet of the leak flow into the are open and unobstructed. Therefore, since the leakage flow can be reliably guided and circulated in the air flow path (29) between the adjacent wall portions (27), an excellent effect of guiding the leakage flow can be obtained.

  In the course of the leakage flow flowing in the inclined direction reaching the wall (27) and passing through the air flow path (29) between the adjacent wall portions (27), the air flow path (29) corrects the direction of leakage flow in the axial direction. Therefore, compared to the case where the plurality of wall portions (27) are not provided, the resistance that air receives during circulation increases. Thereby, the quantity of the leakage flow branched from the main flow can be reduced. Moreover, in the vicinity of the air suction port (19a), the flow direction of the leakage flow rectified by the air flow path (29) is close to the axial direction, which is the main flow direction. Therefore, when the leakage flow merges with the main flow in the vicinity of the air suction port (19a), the degree of interference of the leakage flow with the main flow is reduced. Therefore, it is possible to suppress a decrease in fan efficiency due to the leakage flow.

  (2) In the centrifugal blower, the bell mouth body (22) includes a first flare portion (221) having an inner diameter and an outer diameter that decrease from the front (F) to the rear (R) in the axial direction; The shroud (19) is located behind the first flare portion (221) in the axial direction (R) and has a predetermined gap between it and the peripheral edge portion (19e) of the air suction port (19a). ) And a second flare portion (222) having an inner diameter and an outer diameter that increase from the front (F) to the rear (R) in the axial direction. The belt-like member (28) is preferably wound around the outer peripheral surface (22s) of the first flare portion (221) along its circumferential direction.

  In this configuration, when the bell mouth (25) has the first flare portion (221) and the second flare portion (222) and has a plurality of wall portions (27), the first flare portion (221) and A bell mouth (25) having a plurality of wall portions (27) only by winding a belt-like member (28) separate from the second flare portion (222) around the outer peripheral surface (22s) of the first flare portion (221). Can be produced.

  Further, when the bell mouth (25) is manufactured by molding means such as injection molding, there are the following advantages. In other words, a conventional bell mouth is manufactured by a molding means such as injection molding using a pair of molds arranged to face each other in the radial direction. However, when the bell mouth (25) has the first flare portion (221) and the second flare portion (222) and has a plurality of wall portions (27), the pair of gold is removed from the molded body after the injection molding. Since the mold cannot be pulled away in the radial direction, the bell mouth (25) cannot be integrally molded using the molding means as described above.

  On the other hand, in this configuration, the belt-like member (28) is separate from the bell mouth main body (22) including the first flare portion (221) and the second flare portion (222). ) Can be produced, for example, by a molding means such as injection molding using a pair of molds arranged opposite to each other in the radial direction.Separately, the belt-shaped member (28) is formed by, for example, injection molding. It can be produced using molding means. Then, the bell mouth (25) can be produced simply by winding the produced belt-like member (28) around the outer peripheral surface (22s) of the first flare portion (221).

  (3) In the centrifugal blower, the material constituting the belt-like member (28) is preferably softer than the material constituting the bell mouth body (22).

  In this configuration, since the material constituting the belt-like member (28) is softer than the material constituting the bell mouth body (22), the belt-like member (28) is the outer peripheral surface of the bell mouth body (22) ( 22s) is easy to fit, and the workability when the belt-like member (28) is wound around the outer peripheral surface (22s) of the bell mouth body (22) is easy.

  (4) In the centrifugal blower, the axial length of each wall portion (27) is larger than the axial length of the belt portion (26), and each wall portion (27) includes the belt portion. A connecting part (271) connected to (26) and standing up from the outer peripheral surface (26s) of the belt part (26), and the front part (F) in the axial direction from the connecting part (271) and the belt part (26). And an extended portion (271) standing up from the outer peripheral surface (22s) of the bell mouth main body (22).

  In this configuration, the connection part (271) of each wall part (27) is directly connected to the belt part (26), while the extension part (272) is not directly connected to the belt part (26). Accordingly, the axial length of the belt portion (26) can be reduced, and the rigidity of the belt portion (26) can be reduced. Therefore, for example, when transporting a large number of belt-like members (28), the degree of freedom to change the shape of each belt-like member (28) according to its packing form so that these belt-like members (28) are not bulky. Will increase. Thereby, transportation cost can be reduced. Further, since the rigidity of the belt portion (26) is small, the belt portion (26) can be easily fitted to the outer peripheral surface (22s) of the first flare portion (221). Therefore, workability when the belt-like member (28) is wound around the outer peripheral surface (22s) of the first flare portion (221) is improved.

  Further, in this configuration, the connection part (271) of each wall part (27) is directly connected to the belt part (26), while the extension part (272) is not directly connected to the belt part (26). Therefore, it becomes easier to fit the extension part (272) of each wall part (27) to the outer peripheral surface (22s) of the first flare part (221). Therefore, workability when the belt-like member (28) is attached to the outer peripheral surface (22s) of the first flare portion (221) is further improved.

  (5) In the centrifugal blower, the standing height from the outer peripheral surface (22s) of the bell mouth main body (22) at the front end (27f) of each wall portion (27) is as follows. It is preferable that the height is higher than the standing height from the outer peripheral surface (22s) of the bell mouth main body (22) at the rear (R) end (27r) of (27).

  In this configuration, each wall portion (27) can catch a large amount of leakage flow at the rear end portion where the standing height is large and guide it to the air flow path (29), while the standing height is At the front end portion with a small length, contact with the peripheral edge portion of the air intake port of the shroud can be suppressed.

  (6) In the centrifugal fan, the height of each wall portion (27) from the outer peripheral surface (22s) of the bell mouth main body (22) is from the rear (R) end portion (27r) to the front (F It is preferable that it gradually increases toward the end portion (27f).

  In this configuration, since the standing height of each wall portion changes smoothly, the air flow in the air flow path becomes smoother.

  (7) In the centrifugal fan, the rear (R) end (27r) of each wall (27) has a front height (F) from the outer peripheral surface (22s) of the bell mouth body (22). ) Is an inclined surface that gradually decreases from the rear (R), and the peripheral edge portion (19e) of the air suction port (19a) is an inclined surface that faces the inclined surface of the wall portion (27). Is preferred.

  In this configuration, the rear (R) end portion (27r) of each wall portion (27) and the peripheral edge portion (19e) of the air suction port (19a) are the inclined surfaces facing each other. Each wall part (27) can be extended to the vicinity of a shroud (19), and it can suppress that it mutually contacts at the time of rotation.

  (8) In the centrifugal blower, the axially rear (R) end (27r) of each wall portion (27) is opposite to the axially forward (F) end of the shroud (19). It is preferable that it is located in the position which opposes to a radial direction, or its vicinity.

  In this configuration, the axially rearward (R) end (27r) of each wall (27) is radially opposed to the axially forward (F) end of the shroud (19). Therefore, the leakage flow can be guided to the air suction port (19a) of the shroud (19) or to the vicinity of the air suction port (19a). Thereby, the fall of the fan efficiency resulting from a leak flow can further be suppressed.

  (9) In the centrifugal blower, the axially rear (R) end of each wall (27) is more forward than the axially forward (F) end of the shroud (19) (F ).

  In this configuration, the axially rearward (R) end of each wall (27) is positioned forward (F) relative to the axially forward (F) end of the shroud (19). Therefore, it can prevent that each wall part (27) contacts a shroud (19).

  (10) Since the air conditioner of the present invention includes the centrifugal blower, it is possible to suppress a decrease in fan efficiency due to leakage flow.

  As described above, according to the present invention, it is possible to suppress a decrease in fan efficiency due to leakage flow.

It is sectional drawing which shows the indoor unit provided with the centrifugal blower which concerns on one Embodiment of this invention. It is a bottom view which shows the positional relationship of the impeller in the said indoor unit, a heat exchanger, and a blower outlet. It is a perspective view which shows the impeller of the said centrifugal blower. It is a side view which shows the bell mouth of the said centrifugal blower. It is a top view which shows the bell mouth of the said centrifugal blower. It is a perspective view which shows the belt-shaped member of the said bellmouth. It is the side view to which a part of FIG. 4 was expanded. It is sectional drawing to which some centrifugal fans were expanded. It is sectional drawing which showed the positional relationship of the shroud of the said impeller, and the said bellmouth. The method for molding the bell mouth body of the bell mouth is shown, (A) is a side view showing a state where the molding die is closed before or during molding, and (B) is after molding. It is a side view which shows the state which the metal mold | die for shaping | molding opened. The method for molding the bell mouth body of the bell mouth is shown, (A) is a plan view showing a state where the molding die is closed before or during molding, and (B) is after molding. It is a top view which shows the state which the metal mold | die for shaping | molding opened.

  Hereinafter, a centrifugal blower 51 and an air conditioner 31 including the centrifugal blower 51 according to an embodiment of the present invention will be described with reference to the drawings.

<Overall structure of air conditioner>
As shown in FIG. 1, the air conditioner 31 according to the present embodiment is a ceiling-embedded cassette indoor unit. The air conditioner 31 includes a substantially rectangular parallelepiped housing 33 embedded in an opening provided in the ceiling, and a decorative panel 47 attached to the lower portion of the housing 33. The decorative panel 47 is slightly larger in plan view than the housing 33 and is exposed to the room in a state of covering the opening of the ceiling. The decorative panel 47 has a rectangular suction grill 39 provided in the center thereof, and four elongated rectangular outlets 37 provided along each side of the suction grill 39.

  The air conditioner 31 includes a centrifugal blower (turbo fan) 51, a fan motor 11, a heat exchanger 43, a drain pan 45, an air filter 41, and the like in a housing 33. Centrifugal blower 51 includes an impeller 23 and a bell mouth 25. The fan motor 11 is fixed to the approximate center of the top plate of the housing 33. The rotation shaft 13 of the fan motor 11 extends downward.

  As shown in FIGS. 1 and 2, the heat exchanger 43 has a flat shape with a small thickness. The heat exchanger 43 is disposed so as to surround the periphery of the impeller 23 in a state where it rises upward from a dish-shaped drain pan 45 extending along the lower end portion thereof. The drain pan 45 stores water droplets generated in the heat exchanger 43. The stored water is discharged through a drainage path (not shown).

  The air filter 41 has a size that covers the inlet of the bell mouth 25, and is provided along the suction grill 39 between the bell mouth 25 and the suction grill 39. The air filter 41 captures dust in the air when the air sucked into the housing 33 from the suction grill 39 passes through the air filter 41.

  As shown in FIGS. 1 to 3, the impeller 23 includes a hub 15, a shroud 19, and a plurality of blades 21. The hub 15 is fixed to the lower end portion of the rotating shaft 13 of the fan motor 11. The hub 15 has a circular shape centered on the rotation shaft 13 in plan view.

  The shroud 19 is disposed to face the front F in the axial direction A of the rotary shaft 13 with respect to the hub 15. The shroud 19 has an air suction port 19 a that opens in a circle around the rotation shaft 13. The outer diameter of the shroud 19 increases from the front F toward the rear R.

  The plurality of blades 21 are arranged between the hub 15 and the shroud 19 at a predetermined interval along the circumferential direction of the air suction port 19a. The front F end of each blade 21 is joined to the inner surface of the shroud 19. The rear R end of each blade 21 is joined to the hub 15. Each blade 21 is a backward blade that is inclined in the direction opposite to the rotation direction (backward) with respect to the radial direction of the hub 15.

<Bellmouth structure>
As shown in FIG. 1, the bell mouth 25 is disposed to face the front F in the axial direction A with respect to the shroud 19. As shown in FIGS. 4 and 5, the bell mouth 25 includes a bell mouth main body 22, a belt-like member 28, and a flange portion 24. The flange portion 24 is a portion projecting radially outward from the peripheral edge of the front F of the bell mouth main body 22.

  The bell mouth main body 22 includes a first flare portion 221 and a second flare portion 222. The first flare portion 221 is a portion where the inner diameter and the outer diameter become smaller from the front F in the axial direction A toward the rear R. The second flare portion 222 is a portion that is located rearward R in the axial direction A than the first flare portion 221, and has an inner diameter and an outer diameter that increase from the front F in the axial direction A toward the rear R.

  The bell mouth main body 22 has a through hole 25a penetrating in the front-rear direction. The outer peripheral surface 22 s of the bell mouth main body 22 has a curved shape in which the outer diameter decreases from the front F toward the rear R in the region of the first flare portion 221, and the outer diameter in the region of the second flare portion 222. It has a curved shape that increases from the front F toward the rear R.

  As shown in FIG. 1, the second flare portion 222, which is a part of the rear R of the bell mouth main body 22, is provided with a predetermined gap between the air inlet 19 a and the peripheral edge 19 e of the air inlet 19 a. Is inserted into the shroud 19. Thereby, the bell mouth 25 can guide the air sucked from the front F toward the rear R through the through hole 25 a to the air suction port 19 a of the shroud 19.

  As shown in FIG. 6, the belt-like member 28 has a belt portion 26 that is long in one direction and a plurality of wall portions 27. The belt portion 26 has a thin plate shape having a substantially constant width and a substantially constant thickness. The belt portion 26 is wound around the outer peripheral surface 22s of the bell mouth main body 22 along the circumferential direction. In the present embodiment, the belt portion 26 is wound around the outer peripheral surface 22s of the first flare portion 221 along the circumferential direction.

  The plurality of wall portions 27 are arranged at substantially equal intervals along the longitudinal direction of the belt portion 26. The length of each wall portion 27 in the axial direction A is larger than the length of the belt portion 26 in the axial direction A (the width of the belt portion 26). The belt portion 26 is located at a position adjacent to the rear R connecting portion 271 in each wall portion 27. The connection part 271 of each wall part 27 is directly connected to the belt part 26, whereby the belt part 26 and the plurality of wall parts 27 are integrated. The extension part 272 of the front part F of each wall part 27 is not directly connected to the belt part 26 but extends to the front part F while being curved from the edge of the front part F of the belt part 26.

  As shown in FIGS. 4, 5, and 7, in a state where the belt-like member 28 is fixed to the outer peripheral surface 22 s of the bell mouth main body 22, the plurality of wall portions 27 are arranged around the outer peripheral surface 22 s of the bell mouth main body 22. They are arranged at predetermined intervals along the direction. Each wall portion 27 extends along the outer peripheral surface 22s from the front F toward the rear R so as to be substantially parallel to the axial direction A and substantially parallel to the radial direction of the bell mouth 25.

  Each wall portion 27 is erected (erected) from the outer peripheral surface 26 s of the belt portion 26 and the outer peripheral surface 22 s of the bell mouth main body 22. Specifically, as shown in FIG. 7, the connection part 271 of each wall part 27 stands from the outer peripheral surface 26 s of the belt part 26, and the extension part 272 further forward F is a bell mouth main body. 22 stands up from the outer peripheral surface 22s (the outer peripheral surface 22s of the first flare portion 221).

  The belt-like member 28 is fixed to the bell mouth main body 22 by joining the inner surface of the belt portion 26 to the outer peripheral surface 22 s of the bell mouth main body 22. Although the extension part 272 of each wall 27 does not necessarily have to be joined to the outer peripheral surface 22s of the bell mouth main body 22, in order to suppress flapping of each wall 27 during rotation of the impeller 23, the bell mouth main body It is preferable to be joined to the outer peripheral surface 22 s of 22.

  As a method of joining the belt-shaped member 28 to the bell mouth main body 22, when the belt-shaped member 28 and the bell mouth main body 22 are formed of synthetic resin, welding such as ultrasonic welding, bonding with an adhesive, screwing Examples of the method include joining by protrusions and engagement between protrusions and grooves (holes). When the belt-like member 28 and the bell mouth body 22 are made of metal, in addition to the above-described methods, for example, welding, brazing Examples of the method include appending.

  The material constituting the belt portion 26 is preferably softer than the material constituting the bell mouth body 22. The bell mouth main body 22 is required to be hard to be deformed during use and to maintain a predetermined shape. On the other hand, the belt portion 26 is fixed to the bell mouth main body 22, so that a material softer than the bell mouth main body 22 is used. Can be used. When the material of the belt portion 26 is softer than the material of the bell mouth main body 22, the belt portion 26 can easily fit the outer peripheral surface 22 s of the bell mouth main body 22, and the belt portion 26 can be attached to the outer peripheral surface of the bell mouth main body 22. This makes it easier to work around 22s.

  Moreover, it is preferable that the material which comprises each wall part 27 is softer than the material which comprises the bellmouth main body 22. FIG. Thereby, each wall part 27 becomes easy to fit to the outer peripheral surface 22s of the bellmouth main body 22. FIG. More preferably, the material constituting each wall portion 27 is the same material as the belt portion 26 in that it can be integrally formed with the belt portion 26.

  Specifically, for example, a hard synthetic resin such as acrylonitrile-butadiene-styrene copolymer (ABS) is used as the material of the bell mouth body 22, and a soft synthetic resin such as polypropylene is used as the material of the belt-shaped member 28. be able to. Alternatively, a metal can be used as the material of the bell mouth body 22 and a synthetic resin can be used as the material of the belt-like member 28.

  As shown in FIG. 7, the bell mouth 25 has a plurality of air flow paths 29 surrounded on three sides by adjacent wall portions 27, 27 and outer peripheral surfaces 22s, 26s. The air flow path 29 faces in the direction along the axial direction A. The air flow path 29 is surrounded on both sides and bottom by the adjacent wall portion 27 and the outer peripheral surfaces 22s and 26s of the bell mouth 25. The inlet and the outlet of the leakage flow into the air flow path 29 are Is open and unobstructed. Accordingly, the leakage flow is reliably guided to the inlet of the air flow path 29 between the wall portions 27 and guided in the air flow path 29 from the front F toward the rear R.

  A rear R end (rear end) 27r of each wall 27 is located at a position facing the end of the front F of the shroud 19 in the axial direction A in the radial direction or in the vicinity thereof. The rear end portion 27r of each wall portion 27 may be positioned in front F of the front F end portion of the shroud 19 in the axial direction A.

  As shown in FIGS. 8 and 9, the standing height of each wall portion 27 from the outer peripheral surface 22s (or outer peripheral surface 26s) is from the rear end portion 27r toward the front F end portion (front end portion) 27f. Increasingly. Each wall portion 27 has a standing height Hf at the front end portion 27f larger than a standing height Hr at the rear end portion 27r. The standing height Hr and the standing height Hf are not particularly limited. For example, the standing height Hr is about 1 mm to 10 mm, and the standing height Hf is about 3 mm to 20 mm. it can.

  As shown in FIGS. 7 and 9, the rear end portion 27 r of each wall portion 27 is an inclined surface inclined with respect to the axial direction A. In this inclined surface, the standing height from the outer peripheral surface 22 s gradually decreases from the front F toward the rear R.

  On the other hand, as shown in FIG. 9, the peripheral edge portion 19e of the air suction port 19a is an inclined surface inclined with respect to the axial direction A. The inclined surface of the peripheral edge portion 19e is provided to face the inclined surface of the rear end portion 27r of each wall portion 27. In other words, the tip of the rear end portion 27r of each wall portion 27 is provided at a position (substantially the same height) that substantially faces the tip end of the peripheral edge portion 19e that is the end portion of the front F of the shroud 19 in the radial direction. . Both the inclined surface of the peripheral edge portion 19e and the inclined surface of the end portion 27r of the wall portion 27 are inclined so that the rear R is located on the inner side in the radial direction than the front F. As described above, since the end portions are formed by the inclined surfaces, the rear end portion 27r of each wall portion 27 can be extended to a position facing the peripheral edge portion 19e of the shroud 19 or the vicinity thereof.

  Next, the flow of air in the centrifugal blower 51 will be described. As shown in FIG. 9, the air of the main flow S guided to the air suction port 19a of the shroud 19 by the bell mouth body 22 of the bell mouth 25 is mainly the rotating shaft 13 of the shroud 19 in the vicinity of the air suction port 19a. In the direction along the axial direction A.

  In the conventional centrifugal blower that does not have the wall 27, the leakage flow M1 is caused by the shroud 19 rotating in the rotation direction K in the vicinity of the air suction port 19a as indicated by the broken arrow M1. The air flows in the direction inclined from the axial direction A to the rotational direction K by being influenced by the air flow to K. Therefore, when this leakage flow M1 merges with the main flow S, the flow of the main flow S is disturbed by the leakage flow M1, resulting in an increase in blowing sound and a decrease in fan efficiency.

  On the other hand, in the centrifugal blower 51 of the present embodiment, the leak flow M is along the air flow path 29 surrounded by the adjacent wall portion 27 and the outer peripheral surface 22s of the bell mouth main body 22 as indicated by the dashed-dotted arrow M. Then, it is guided from the front F to the rear R, and passes through a gap between the rear R end of the bell mouth body 22 and the front F end of the shroud 19. The leakage flow M that has passed through the gap is corrected so that the flow direction approaches the axial direction A in the vicinity of the air suction port 19a as compared with the conventional case. Accordingly, interference when the leakage flow M joins the main flow S is suppressed.

  Next, a method for manufacturing the bell mouth 25 will be described by taking as an example the case where the bell mouth 25 is made of synthetic resin. The belt-like member 28 in the present embodiment is not integrally formed with the bell mouth main body 22 and the flange portion 24 but separately formed. As shown in FIGS. 10A and 10B and FIGS. 11A and 11B, the bell mouth body 22 includes an upper mold 61, a lower mold 62, a right mold 63, and a left mold. 64 is used for injection molding.

  The upper mold 61 has a shape along the shape of the inner peripheral surface of the first flare portion 221 and the upper surface of the flange portion 24. The lower mold 62 has a shape along the shape of the inner peripheral surface of the second flare portion 222. The right mold 63 has a shape along the shape of the outer peripheral surface of the first flare portion 221, the outer peripheral surface of the second flare portion 222, and the lower surface of the flange portion 24. The left mold 64 has a shape along the shape of the outer peripheral surface of the first flare portion 221, the outer peripheral surface of the second flare portion 222, and the lower surface of the flange portion 24. The upper mold 61 and the lower mold 62 are slidable in a direction in which they are separated from each other (vertical direction). The right mold 63 and the left mold 64 are slidable in a direction in which they are separated from each other (left and right direction).

  As shown in FIGS. 10 (A) and 11 (A), when these dies 61 to 64 are in a state of being closest to each other, a space having the same shape as the bell mouth main body 22 is formed in the interior. The molten resin is injected. Thereafter, as shown in FIGS. 10B and 11B, the molds slide in a direction away from each other, and the molded body (bell mouth main body 22 and flange portion 24) is taken out.

  The belt-like member 28 can be molded using a molding means such as injection molding. And the bell mouth 25 is obtained by joining the obtained belt-shaped member 28 to the outer peripheral surface 22s of the bell mouth main body 22 using the joining means mentioned above.

<Outline of Embodiment>
This embodiment is summarized as follows.

  (1) In the present embodiment, since the bell mouth 25 has a plurality of wall portions 27, the wall portion 27 serves as a resistance to leakage flow, and the amount of leakage flow can be reduced. Moreover, since the direction of the leakage flow can be made closer to the direction of the main flow, it is possible to suppress the main flow from being disturbed when the leakage flow joins the main flow. Thereby, the fall of fan efficiency can be suppressed and the noise reduction effect can also be expected.

  Further, in the present embodiment, the bell mouth 25 having the plurality of wall portions 27 can be easily produced simply by wrapping the belt-like member 28 separate from the bell mouth main body 22 around the outer peripheral surface 22 s of the bell mouth main body 22. it can. Therefore, the bell mouth 25 can be molded using various materials such as metal and resin. Further, since the belt-like member 28 is a separate member from the bell mouth main body 22, the bell mouth main body 22 and the belt-like member 28 can be manufactured using different materials.

  (2) In this embodiment, when the bell mouth 25 has the first flare portion 221 and the second flare portion 222 and also has the plurality of wall portions 27, the first flare portion 221 and the second flare portion 222 The bell mouth 25 having a plurality of wall portions 27 can be produced simply by winding a separate belt-like member 28 around the outer peripheral surface 22 s of the first flare portion 221.

  Further, when the bell mouth 25 is manufactured by molding means such as injection molding, there are the following advantages. In other words, a conventional bell mouth is manufactured by a molding means such as injection molding using a pair of molds arranged to face each other in the radial direction. However, in the case where the bell mouth 25 has the first flare portion 221 and the second flare portion 222 and has a plurality of wall portions 27, the bell mouth 25 can be integrally formed using the forming means as described above. Can not.

  On the other hand, in the present embodiment, since the belt-like member 28 is separate from the bell mouth main body 22 including the first flare portion 221 and the second flare portion 222, the bell mouth main body 22 is opposed to these radial directions, for example. The belt-shaped member 28 can be manufactured using a molding means such as injection molding, for example, by using a pair of arranged molds by a molding means such as injection molding. The bell mouth 25 can be manufactured simply by winding the manufactured belt-shaped member 28 around the outer peripheral surface 22s of the first flare portion 221.

  (3) In the present embodiment, since the material constituting the belt-like member 28 is softer than the material constituting the bell mouth main body 22, the belt-like member 28 can easily fit the outer peripheral surface 22 s of the bell mouth main body 22. Moreover, the workability when the belt-shaped member 28 is wound around the outer peripheral surface 22s of the bell mouth main body 22 is excellent.

  (4) In the present embodiment, the connection portion 271 of each wall portion 27 is directly connected to the belt portion 26, while the extension portion 272 is not directly connected to the belt portion 26, so that the belt portion 26 is correspondingly increased. The axial length of the belt portion 26 can be reduced, and the rigidity of the belt portion 26 can be reduced. Therefore, for example, when a large number of belt-like members 28 are transported, the degree of freedom of changing the shape of each belt-like member 28 according to its packing form is increased so that these belt-like members 28 are not bulky. Thereby, transportation cost can be reduced. Further, since the rigidity of the belt portion 26 is small, it is easy to fit the belt portion 26 to the outer peripheral surface 22s of the first flare portion 221. Therefore, workability when the belt-like member 28 is wound around the outer peripheral surface 22s of the first flare portion 221 is improved.

  In the present embodiment, since the extended portion 272 of each wall portion 27 is not directly connected to the belt portion 26, the extended portion 272 of each wall portion 27 is further fitted to the outer peripheral surface 22 s of the first flare portion 221. It becomes easy to let you. Therefore, workability when attaching the belt-like member 28 to the outer peripheral surface 22s of the first flare portion 221 is further improved.

  (5) In the present embodiment, the standing height from the outer peripheral surface 22s of the bell mouth main body 22 at the front end portion 27f of each wall portion 27 is the height of the bell mouth main body 22 at the rear end portion 27r of each wall portion 27. It is larger than the standing height from the outer peripheral surface 22s. Therefore, each wall portion 27 can catch a large amount of leakage flow at the rear end portion 27r having a large standing height and guide it to the air flow path, while at the front end portion 27f having a small standing height. Can suppress contact with the periphery of the air inlet of the shroud.

  (6) In this embodiment, the standing height of each wall 27 from the outer peripheral surface 22s of the bell mouth main body 22 gradually increases from the rear end 27r toward the front end 27f. That is, since the standing height of each wall portion changes smoothly, the air flow in the air flow path becomes smoother.

  (7) In this embodiment, the rear end portion 27r of each wall portion and the peripheral edge portion 19e of the air suction port 19a are the inclined surfaces facing each other, and therefore each wall portion 27 can be extended to the vicinity of the shroud. And it can suppress that each other contacts at the time of rotation.

  (8) In the present embodiment, the rear end portion 27r of each wall portion 27 is located at a position facing the end portion of the front F of the shroud 19 in the axial direction A in the radial direction or in the vicinity thereof. The leakage flow can be guided to the air inlet 19a of the shroud 19 or to the vicinity of the air inlet 19a. Thereby, the fall of the fan efficiency resulting from a leak flow can further be suppressed.

  (9) In the present embodiment, the rear end portion 27r of each wall portion 27 is positioned forward F rather than the front F end portion of the shroud 19 in the axial direction A. Therefore, each wall portion 27 is connected to the shroud 19. Contact can be prevented.

<Other embodiments>
As mentioned above, although embodiment of this invention was described, this invention is not limited to each said embodiment, A various change, improvement, etc. are possible in the range which does not deviate from the meaning.

  For example, in the above-described embodiment, the case where the bell mouth main body 22 includes the first flare portion 221 and the second flare portion 222 is illustrated, but the present invention is not limited to this. The bell mouth main body 22 does not necessarily have the second flare portion 222.

  Moreover, although the said embodiment illustrated the case where the length of the axial direction A of each wall part 27 was larger than the length of the axial direction A of the belt part 26, it is not limited to this. The length of each wall portion 27 in the axial direction A may be approximately the same as the length of the belt portion 26 in the axial direction A, or may be smaller than the length of the belt portion 26 in the axial direction A. In this case, the entire wall portion 27 is connected to the belt portion 26, and the entire wall portion 27 is erected from the belt portion 26 (the entire wall portion 27 becomes the connection portion 271). The substantially entire outer peripheral surface 22s of the first flare portion 221 is covered.

  Moreover, although the belt part 26 (connection part 271 of each wall part 27) was in the position of the back R in the belt-like member 28 in the said embodiment, it illustrated, but it is not limited to this. The belt portion 26 (the connection portion 271 of each wall portion 27) may be located at the front F position or the center position of the belt-like member 28.

  Moreover, although the case where the material which comprises the belt-shaped member 28 was softer than the material which comprises the bellmouth main body 22 was illustrated in the said embodiment, it is not limited to this. The material constituting the belt-like member 28 may be the same as the material constituting the bell mouth body 22.

  Moreover, in the said embodiment, although the form which increased the said standing height of each wall part gradually from back to front was illustrated, the said standing height was increased stepwise from back to front. May be. Moreover, the said standing height of each wall part may be constant from back to front, and may decrease toward the front from the back.

  Moreover, in the said embodiment, the rear-end part of each wall part is an inclined surface from which the said standing height reduces gradually toward the back from the said front, The said peripheral part of the said air inlet is the said wall part However, the present invention is not limited to this example. The rear end portion of each wall portion may be a surface perpendicular to the axial direction instead of an inclined surface. Similarly, the peripheral edge portion of the air suction port may be a surface perpendicular to the axial direction.

  Moreover, in the said embodiment, when the front-end | tip of the rear-end part of each wall part is provided in the position (substantially the same height) which opposes the front-end | tip of the peripheral part which is the edge part ahead of a shroud in radial direction. However, the present invention is not limited to this. The rear end portion of each wall portion may be provided in front of or behind the front end portion of the shroud.

  Moreover, in the said embodiment, although the case where the centrifugal air blower was used for the ceiling embedded type cassette indoor unit was illustrated, it can be used for other types of indoor units, and for other uses other than the air conditioner. It can also be used.

DESCRIPTION OF SYMBOLS 11 Fan motor 13 Rotating shaft 15 Hub 17 Air suction inlet 19 Shroud 19a Air suction inlet 19e Peripheral edge part of air suction inlet 21 Blade 22 Bell mouth main body 221 First flare portion 222 Second flare portion 23 Impeller 24 Flange portion 25 Bell mouth 25a Through-hole 22s Peripheral surface of bell mouth main body 26 Belt portion 27 Wall portion 27f Front end portion of wall portion 27r Rear end portion of wall portion 28 Belt-like member 29 Air flow path 31 Indoor unit A Axial direction of rotation axis of fan motor F Front R Rear

Claims (10)

A shroud (19) having an air suction port (19a) that opens in a circle, and a plurality of blades (21) arranged on the inner surface of the shroud (19) along the circumferential direction of the air suction port (19a). An impeller (23) fixed to the rotating shaft (13) of the fan motor (11),
A bell mouth (25) disposed forward (F) in the axial direction of the rotating shaft (13) rather than the shroud (19), and
The bell mouth (25)
The portion where the inner diameter and outer diameter become smaller from the front (F) in the axial direction toward the rear (R), and the rear (R) in the axial direction than this portion, the air suction port (19a) A bell mouth body (22) including a portion inserted into the shroud (19) in a state where a predetermined gap is provided between the peripheral edge portion (19e),
A belt-shaped member (28) including a belt portion (26) wound around the outer peripheral surface (22s) of the bell mouth main body (22) in the circumferential direction and a plurality of wall portions (27) connected to the belt portion (26). ), And
The plurality of wall portions (27) are arranged at predetermined intervals along the circumferential direction of the outer peripheral surface (22s), and each wall portion (27) is arranged on the outer peripheral surface (26s) of the belt portion (26). ) And at least one of the outer peripheral surfaces (22s) of the bell mouth body (22), and the front (F) in the axial direction so as to be substantially parallel to the axial direction and the radial direction of the bell mouth (25). A centrifugal blower extending along the outer peripheral surface (22s) of the bell mouth main body (22) from the rear to the rear (R). The bell mouth body (22)
A first flare portion (221) having an inner diameter and an outer diameter that decrease from the front (F) to the rear (R) in the axial direction;
The shroud (R) is located rearward (R) in the axial direction with respect to the first flare portion (221), and a predetermined gap is provided between the peripheral portion (19e) of the air suction port (19a). 19) a second flare portion (222) inserted in the axial direction and having an inner diameter and an outer diameter that increase from the front (F) to the rear (R) in the axial direction,
The centrifugal blower according to claim 1, wherein the belt-like member (28) is wound around an outer peripheral surface (22s) of the first flare portion (221) along a circumferential direction thereof.   The centrifugal blower according to claim 1 or 2, wherein a material constituting the belt-shaped member (28) is softer than a material constituting the bell mouth main body (22). The axial length of each wall portion (27) is larger than the axial length of the belt portion (26),
Each wall portion (27) is connected to the belt portion (26) and rises from the outer peripheral surface (26s) of the belt portion (26), and the connection portion (271) and the belt portion ( 26) and an extension part (272) that is located in front of the axial direction (F) of the bell mouth main body (22) and rises from the outer peripheral surface (22s) of the bell mouth main body (22). The centrifugal blower according to item 1.   The standing height from the outer peripheral surface (22s) of the bell mouth body (22) at the front (F) end (27f) of each wall (27) is the rear (R) of each wall (27). The centrifugal blower according to any one of claims 1 to 4, wherein the centrifugal fan is larger than a standing height from an outer peripheral surface (22s) of the bell mouth main body (22) at an end portion (27r) thereof.   The height of each wall (27) from the outer peripheral surface (22s) of the bell mouth main body (22) is from the rear (R) end (27r) to the front (F) end (27f). The centrifugal blower according to claim 5, wherein the centrifugal blower gradually increases. The rear (R) end (27r) of each wall portion (27) is such that the standing height from the outer peripheral surface (22s) of the bell mouth body (22) is from the front (F) to the rear (R). Is an inclined surface that gradually decreases,
The centrifugal blower according to any one of claims 1 to 6, wherein the peripheral edge portion (19e) of the air suction port (19a) is an inclined surface facing the inclined surface of the wall portion (27).   The axially rearward (R) end of each wall (27) is at or near a position facing the axially forward (F) end of the shroud (19) in the radial direction. The centrifugal blower according to claim 1, wherein the centrifugal blower is located.   The axially rear (R) end of each wall (27) is positioned forward (F) relative to the axially forward (F) end of the shroud (19). Item 8. The centrifugal blower according to Item 7.   The air conditioner provided with the centrifugal blower of any one of Claims 1-9.

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