JP2009250112A - Impeller of centrifugal blower - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce noise by separation of an air current, by utilizing a weight-reduction structure of a blade part of a centrifugal blower. <P>SOLUTION: This invention is an impeller of the centrifugal blower of forming a blade in a hollow shape for solving such the problem. The noise is absorbed and reduced by generating a Helmholtz type resonance phenomenon by arranging a large number of small holes penetrating through a hollow part in the respective blade on the positive pressure surface side or the negative pressure surface side or both these surface sides of the respective blades. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a blade structure of an impeller of a centrifugal blower.

  In general, centrifugal fans such as turbofans have a large problem of noise, and reduction of noise is a problem. Therefore, as a noise reduction technique for such a centrifugal blower, for example, the blade (blade) is a thick blade, that is, an airfoil blade, to reduce the separation of the airflow around the blade and to reduce the noise as much as possible. (See Patent Document 1).

  However, the thick blade has a problem that the weight increases, the driving load increases, and the material cost increases.

  In view of this, a structure in which such a thick wing blade is formed in a hollow shape to reduce weight and cost has been proposed (see Patent Document 2).

JP 2002-339897 A JP 2005-155510 A

  However, even with an airfoil wing such as the former and a light airfoil wing such as the latter, it is not possible to completely eliminate the air separation itself, and the problem of noise reduction remains.

  The present invention has been made to solve such problems, and in the impeller of a centrifugal blower in which the blades are hollow, each of the blades on the pressure surface side or suction surface side, or on both surfaces thereof. An object of the present invention is to provide an impeller of a centrifugal blower with high silent performance that generates Helmholtz-type resonance and absorbs and reduces noise by providing a large number of small holes penetrating through the hollow portion in the blade. It is.

  In order to achieve the above object, the present invention comprises the following problem solving means.

(1) First problem-solving means The first problem-solving means is a centrifugal blower impeller in which each blade of a plurality of blades is hollow. A large number of small holes penetrating the hollow portion are provided.

  Separation is likely to occur on the suction surface side of the blade, and generally the noise on the suction surface side is higher than that on the pressure surface side. Therefore, a large number of small holes that penetrate the hollow portion in the blade are provided on the suction surface side of the blade to effectively absorb such high noise.

  That is, in an impeller of a centrifugal blower in which each blade of a plurality of blades is hollow, if a large number of small holes that penetrate the hollow portion in each blade are provided on the suction surface side of each blade, Noise generated on the suction side of each blade enters each small hole, and Helmholtz resonance is generated by the air layer inside the blade, and the noise at the same frequency as the resonance frequency is absorbed, making the fan noise effective. Reduced to

(2) Second problem-solving means This second problem-solving means is an impeller of a centrifugal blower in which each blade of a plurality of blades is hollow. A large number of small holes penetrating the hollow portion are provided.

  Even on the pressure surface side of the blade, separation may occur and noise may be generated. Therefore, a large number of small holes that penetrate the hollow portion in the blade are provided on the pressure surface side of the blade to effectively absorb such noise.

  That is, in an impeller of a centrifugal blower in which each blade of a plurality of blades is hollow, if a large number of small holes that penetrate the hollow portion in each blade are provided on the pressure surface side of each blade, Noise generated on the pressure surface side of each blade enters each small hole, the Helmholtz resonance is generated by the air layer inside the blade, and the noise of the same frequency as the resonance frequency is absorbed, and the fan noise is effective Reduced to

(3) Third Problem Solving Means This third problem solving means is provided in the impeller of a centrifugal blower in which each blade of a plurality of blades is hollow, on the pressure surface side and the suction surface side of each blade. Each is provided with a large number of small holes penetrating through the hollow portion in each blade.

  Separation occurs and noise is generated not only on the suction side of the blade but also on the pressure side. Therefore, a large number of small holes penetrating the hollow portion in the blade are provided on each of the pressure surface side and the suction surface side of the blade to effectively absorb such noise.

  That is, in the impeller of a centrifugal blower in which each blade of a plurality of blades is hollow, a plurality of small holes that penetrate the hollow portion in each blade are provided on each of the suction surface side and the pressure surface side of each blade. The noise generated on the suction side and the pressure side of each blade enters each small hole, and the Helmholtz resonance is generated by the air layer in the hollow inside the blade, which is the same as the resonance frequency. Frequency noise is absorbed and fan noise is effectively reduced.

(4) Fourth Problem Solving Means In the fourth problem solving means, in the configuration of the first, second, or third problem solving means, each small hole has a constant relationship with each other while maintaining a constant pitch. It is characterized by being arranged by.

  In order to generate effective Helmholtz resonance with the hollow part inside the blade, it is important that the pitch between the small holes is constant, and the pitches are arranged at a constant pitch. Effective noise absorption.

(5) Fifth Problem Solving Means In the fifth problem solving means, in the configuration of the first, second, third, or fourth problem solving means, the diameter of each small hole does not exceed 3 mm. It is characterized by a diameter.

  If the diameter of each small hole is 3 mm or more, the noise generated by the hole itself due to the edge of the small hole neck becomes high, and the low noise effect cannot be obtained.

  Therefore, the diameter of each small hole is preferably in a range not exceeding 3 mm.

(6) Sixth problem solving means This sixth problem solving means is for the blower of an indoor unit for an air conditioner in the configuration of the first, second, third, fourth or fifth problem solving means. It is characterized by being configured as an impeller.

  An indoor unit for an air conditioner is required to have a large air volume and quietness.

  Therefore, the centrifugal blower according to each of the above claims is optimal because of its high blowing performance and low noise.

  As a result, according to the present invention, it is possible to achieve both reduction in weight by the hollow blade and effective reduction in noise.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of a centrifugal blower impeller according to the present invention applied to an air conditioner and a centrifugal blower including the same will be described in detail with reference to the accompanying drawings.

(1) Overall Configuration of Air Conditioner First, FIG. 1 is an external perspective view of an air conditioner 1 in which an impeller of a centrifugal blower according to an embodiment of the present invention and a centrifugal blower equipped with the impeller are employed (the ceiling portion is omitted). ). The air conditioner 1 is a ceiling-embedded air conditioner, and includes a casing 2 that houses various components therein, and a decorative panel 3 that is disposed below the casing 2. Specifically, the casing 2 of the air conditioner 1 is inserted and arranged in an opening formed in the ceiling U of the air conditioning room, as shown in FIG. 2 (a schematic side sectional view of the air conditioner 1). Yes. And the decorative panel 3 is arrange | positioned so that it may fit in the opening of the ceiling part U. FIG.

  The casing 2 is a box-like body having a substantially octagonal lower surface in which long sides and short sides are alternately formed in a plan view, and approximately 8 in which long sides and short sides are alternately formed. A square-shaped top plate 21 and side plates 22 extending downward from the peripheral edge of the top plate 21 are provided.

  The decorative panel 3 is a plate-like body having a substantially quadrangular shape in plan view, and is formed so as to correspond to each of the four sides with an air inlet 31 for sucking air in the air-conditioned room at the substantially center thereof. And a plurality (four in this embodiment) of air outlets 32 for blowing air out of the air conditioning chamber. Each side of the decorative panel 3 is arranged so as to correspond to each long side of the top plate 21 of the casing 2.

  The air inlet 31 is a substantially square opening in the present embodiment. On the other hand, the four air outlets 32 are substantially rectangular openings that are elongated in the direction along each side of the decorative panel 3. The air suction port 31 is provided with a suction grill 33 and a filter 34 for removing dust in the air sucked from the air suction port 31. Further, each air outlet 32 is provided with a horizontal flap 35 that can swing around an axis in the longitudinal direction. The horizontal flap 35 is a substantially rectangular blade member that is elongated in the longitudinal direction of each air outlet 32, and rotationally drives shaft support pins provided at both ends in the longitudinal direction by a motor (not shown). Thus, the direction of air blown out from the air outlet 32 toward the air-conditioned room is varied.

  Inside the casing 2, a blower 4 that mainly sucks air in the air-conditioned room into the casing 2 through the air inlet 31 of the decorative panel 3 and blows it out in the outer peripheral direction, and heat disposed so as to surround the outer periphery of the blower 4. An exchanger 6 is arranged.

  The blower 4 is a turbo fan as one of centrifugal blowers targeted by the present invention in the present embodiment, and a fan motor 41 (impeller driving means) provided at the center of the top plate 21 of the casing 2; It has the impeller 42 connected with the shaft 41a (rotating shaft) of the fan motor 41, and rotationally driven. The detailed structure of the impeller 42 will be described later.

  In this embodiment, the heat exchanger 6 is a cross fin tube type heat exchanger panel formed by being bent so as to surround the outer periphery of the blower 4, and is an outdoor unit (not shown) installed outdoors or the like. Is connected via a refrigerant pipe. The heat exchanger 6 can function as an evaporator during cooling operation and as a condenser during heating operation. Thereby, the heat exchanger 6 performs heat exchange with the air sucked into the casing 2 through the air suction port 31 by the blower 4, and cools the air during the cooling operation and heats the air during the heating operation.

  A drain pan 7 for receiving drain water generated by condensation of moisture in the air in the heat exchanger 6 is disposed below the heat exchanger 6. The drain pan 7 is attached to the lower part of the casing 2. The drain pan 7 includes a suction hole 71 formed so as to communicate with the air suction port 31 of the decorative panel 3, a blowout hole 72 formed so as to correspond to the air outlet 32 of the decorative panel 3, and the heat exchanger 6. And a drain water receiving groove 73 for receiving drain water.

  A bell mouth 5 for guiding the air sucked from the air suction port 31 to the impeller 42 of the blower 4 is disposed in the suction hole 71 of the drain pan 7.

  As described above, in the air conditioner 1, the air inlet 31 of the decorative panel 3 passes through the filter 34, the bell mouth 5, the drain pan 7, the blower 4, and the heat exchanger 6 to the four air outlets 32. An air flow path is formed so that air in the air-conditioned room is sucked and heat-exchanged in the heat exchanger 6 and then blown out into the air-conditioned room.

(2) Structure of Impeller of Centrifugal Blower Next, the structure of the impeller 42 of the centrifugal blower will be specifically described with reference to FIGS. 2, 3, and 4. Here, FIG. 3 is an external perspective view of the impeller 42. 4 is a view in the direction of arrow A in FIG. 3 (illustrated excluding a part of the end ring 45).

  The impeller 42 is mainly arranged in a ring shape on the side opposite to the fan motor 41 of the end plate 43 centering on the shaft 41a and a disc-shaped end plate 43 (main plate) connected to the shaft 41a of the fan motor 41. In addition, a plurality of (seven in this embodiment) blades 44 and an annular end ring 45 (side plate) disposed so as to sandwich the plurality of blades 44 between the end plates 43 in the axial direction. . Here, the rotation direction of the impeller 42 is indicated as R.

  The end plate 43 is a resin member formed at the center thereof so that a substantially conical convex portion 43a protrudes toward the air suction port 31 side. A plurality of (in this embodiment, five) cooling air holes 43b made of long holes formed side by side on the concentric circle of the end plate 43 are formed in the convex portion 43a. Further, a hub cover 46 is fixed to the surface of the end plate 43 on the side opposite to the fan motor 41 so as to cover the plurality of cooling air holes 43b with a predetermined space between the end plate 43 and the end plate 43. The hub cover 46 has a plurality (five in this embodiment) of guide blades 46a provided on the end plate 43 side surface so as to protrude radially. Thereby, a part of the air blown to the outer peripheral side of the impeller 42 is a pressure between the static pressure in the space on the fan motor 41 side of the end plate 43 and the static pressure in the space on the side opposite to the fan motor 41 of the end plate 43. Due to the difference, the fan motor 41 is cooled by passing through the vicinity of the fan motor 41, and then the space inside the impeller 42 again through the cooling air holes 43b of the end plate 43 and the guide blades 46a of the hub cover 46. To be blown out.

  The end ring 45 is a bell-shaped resin member that protrudes toward the air suction port 31 from the outer peripheral portion toward the opening in the central portion.

(3) Structure of Blade Part of Impeller Next, the structure of the blade 44 will be specifically described with reference to FIGS. Here, FIG. 5 is a schematic side view of the blade 44. 6 is a cross-sectional view taken along line BB in FIG. 7 is a cross-sectional view taken along the line CC of FIG.

  In the case of this embodiment, the blade 44 is a resin member molded separately from the above-described end plate 43 and end ring 45, one end of which is fixed to the end plate 43, and the other end to the end ring 45. It is fixed. The blade portion has a blade shape in which the end portion 44a on the end plate 43 side tilts backward from the end portion 44b on the end ring 45 side in a plan view of the impeller 42. In view, these end portions 44a and 44b are formed to intersect each other. That is, the blade portion of the blade 44 has a three-dimensional shape extending in the axial direction while twisting between the end plate 43 and the end ring 45 (hereinafter, this is defined as a three-dimensional blade).

  In this embodiment, the end of the blade 44, which is a three-dimensional blade, on the R direction (hereinafter referred to as the front edge) is stepped toward the inner peripheral side of the impeller 42 (this embodiment). In the embodiment, the front edge corner portions 44c and 44c are formed so as to protrude in two steps). The front edge corners 44c and 44c are separated from the negative pressure surface 44f of the blade 44 when the airflow sucked into the impeller 42 through the air suction port 31 and the bell mouth 5 is blown to the outer peripheral side by the blade 44. This contributes to reducing the noise of the blower 4. Here, the negative pressure surface 44f indicates a surface of the blade 44 facing the inner peripheral side of the impeller 42, and is a surface on the opposite side of the negative pressure surface 44f, that is, a surface of the blade 44 facing the outer peripheral side of the impeller 42. Is the pressure surface 44e.

  In the case of the present embodiment, a plurality of trailing edge protrusions 44d having a waveform shape toward the outer peripheral side of the impeller 42 are provided at the end of the blade 44 on the counter-rotating direction side (hereinafter referred to as a trailing edge). , 44d ... are formed. The plurality of trailing edge protrusions 44d, 44d,... Are arranged at the rear of the blade 44 when the airflow sucked into the impeller 42 through the air inlet 31 and the bell mouth 5 is blown out to the outer peripheral side by the blade 44. It has a function of reducing the pressure difference at the boundary between the positive pressure surface 44e and the negative pressure surface 44f at the edge, thereby contributing to reducing the noise of the blower 4.

  The shape and number of the front edge corner portions 44c, 44c and the plurality of rear edge protrusions 44d, 44d,... Are not limited to the shape and number shown in the drawings of the present embodiment. Of course, the front edge portion and the rear edge portion of the blade 44 may have such front edge corner portions 44c, 44c and a plurality of rear edges when there is no need to improve noise performance due to the application. The edge protrusions 44d, 44d, etc. are not necessarily provided.

  Next, a more detailed structure of the blade 44 will be described. That is, in this embodiment, the blade 44 is mounted between the blade body 51 (first surface portion) fixed to the end plate 43 and the end ring 45 and the blade body 51 by being fitted into the blade body 51, for example. It is comprised from the blade lid | cover 61 (2nd surface part) which forms the hollow space S, and, thereby, the very lightweight hollow blade | wing is formed.

  In the present embodiment, the blade body 51 is a plate-like member that mainly forms part of the positive pressure surface 44e and the negative pressure surface 44f of the blade 44 (specifically, the rear edge portion of the negative pressure surface 44f). On the other hand, in this embodiment, the blade lid 61 is mainly composed of a plate-like member that constitutes a part of the negative pressure surface 44f (specifically, a portion excluding the rear edge portion of the negative pressure surface 44f).

  The blade body 51 includes a pressure surface portion 52 that constitutes the pressure surface 44e of the blade 44, a ring side edge portion 53 formed on the end ring 45 side of the pressure surface portion 52, and the pressure surface portion 52. A rear edge side edge portion 54 formed on the rear edge side, a front edge side edge portion 55 formed on the front edge side of the pressure surface portion 52, and a plate side edge portion formed on the end plate 43 side of the pressure surface portion 52. 56.

  The positive pressure surface portion 52 has a plurality (three in the present embodiment) of annular projections 52a, 52a, 52a that protrude toward the blade lid 61 at the substantially central portion thereof.

  The ring-side edge 53 is formed on the ring-side body end 53a extending toward the blade lid 61, and the ring-side edge 63 (described later) of the blade lid 61 formed on the end plate 43 side of the ring-side body end 53a. And a plurality (three in this embodiment) of ring-side abutting portions 53b that abut against each other. The ring-side main body end portion 53a is formed so as to form an end surface from the front edge side to the rear edge side of the blade 44 and to have a stepped shape (in this embodiment, three step portions) with a short distance from the end plate 43. Has been. The ring-side contact portion 53b is formed so as to protrude from the surface of the positive pressure surface portion 52 on the blade lid 61 side toward the blade lid 61 side.

  The trailing edge 54 forms the trailing edge of the pressure surface 44e of the blade 44 and the trailing edge of the suction surface 44f. The trailing edge projections 44d, 44d,. 44d, 44d... Is formed on the front edge side of the blade lid 61 and has a rear edge side contact portion 54a with which a rear edge side edge portion 64 (described later) of the blade lid 61 contacts.

  The front edge side edge 65 constitutes a portion of the front edge corners 44c and 44c on the pressure surface 52 side, is formed on the rear edge side of the front edge corners 44c and 44c, and the front edge side edge of the blade lid 61 A plurality of first front edge side contact portions 55a with which 65 (described later) contacts, and a plurality of front edge side edge portions 65 of the blade lid 61 that are formed on the rear edge side of the first front edge side contact portion 55a (in the present embodiment, 5) second front edge contact portions 55b. The second front edge side contact portion 55a is formed so as to protrude from the surface of the positive pressure surface portion 52 on the blade lid 61 side toward the blade lid 61 side.

  The plate side edge portion 56 has a plate side main body end portion 56a extending toward the blade lid 61 side, and a slit hole 56b and a positioning hole 56c formed in the plate side main body end portion 56a. The slit hole 56b is a slit-like long hole that is disposed along the surface on the blade body 51 side of the plate-side edge portion 66 (described later) of the blade lid 61 at the approximate center of the plate-side body end portion 56a. The positioning hole 56c is a circular hole arranged on the front edge side of the slit hole 56b.

  The blade lid 61 includes a negative pressure surface portion 62 constituting a part of the negative pressure surface 44f of the blade 44 (specifically, a portion excluding the rear edge portion of the negative pressure surface 44f), and an end ring 45 side of the negative pressure surface portion 62. The formed ring side edge portion 63, the rear edge side edge portion 64 formed on the rear edge side of the suction surface portion 62, the front edge side edge portion 65 formed on the front edge side of the suction surface portion 62, and the suction surface portion 62. And a plate side edge portion 66 formed on the end plate 43 side.

  The negative pressure surface portion 62 has a plurality (three in this embodiment) of fitting protrusions 62a that protrude toward the blade main body 51 at positions corresponding to the annular protrusions 52a formed on the positive pressure surface portion 52 of the blade main body 51. have. Each of the fitting protrusions 62a is fitted in the concave portion at the center of the corresponding annular protrusion 52a, and the surface of the negative pressure surface portion 62 on the blade body 51 side contacts the end of the annular protrusion 52a on the blade lid 61 side. It is inserted until the surface of the positive pressure surface portion 52 on the blade lid 61 side comes into contact with the end portion of the fitting projection 62a on the blade body 51 side.

  The ring side edge portion 63 has a shape along the stepped end surface of the ring side main body end portion 53a, the end surface of the ring side main body end portion 53a on the blade cover 61 side, and the blade cover of the ring side contact portion 53b. It contacts the end surface on the 61 side. Here, the end surface on the end ring 45 side of the ring side main body end portion 53a slightly protrudes toward the end ring 45 side than the end surface on the end ring 45 side of the ring side main body end portion 63a. The ring side edge 53 of the blade body 51 and the ring side edge 63 of the blade lid 61 constitute an end 44b fixed to the end ring 45.

  The trailing edge side edge portion 64 has a shape along the trailing edge side edge portion 54 and is in contact with the end surface of the trailing edge side contact portion 54a on the blade lid 61 side.

  The front edge side edge portion 65 constitutes a portion of the front edge corner portions 44c, 44c on the suction surface portion 62 side, the end surface on the blade lid 61 side of the first front edge side contact portion 55a and the second front edge side contact. It abuts on the end surface of the portion 55b on the blade lid 61 side.

  The plate side edge portion 66 has a shape along the end surface of the ring side main body end portion 53a, and abuts on the end surface on the end ring 45 side of the plate side main body end portion 56a. An engaging claw 66a that can be inserted into the slit hole 56b from the end ring 45 side toward the end plate 43 side is formed at the end of the plate side edge portion 66 on the end plate 43 side. Here, the engaging claw 66a is formed so as not to protrude from the end surface on the end plate 43 side of the plate-side main body end portion 56a in a state of being inserted into the slit hole 56b. The plate side edge 56 of the blade body 51 and the plate side edge 66 of the blade lid 61 constitute an end 44 a that is fixed to the end plate 43.

  The blade 44 inserts the engaging claws 66 a of the blade lid 61 into the slit holes 56 b of the blade body 51, and then fits the edges 63 to 66 of the blade lid 61 into the edges 53 to 56 of the blade body 51. Assembled by putting in. Thereby, a hollow portion (hollow space) S as shown in FIGS. 6 and 7 is formed between the blade body 51 and the blade lid 61. In addition, since the blade body 51 and the blade lid 61 are molded separately, there are few restrictions on the mold drawing direction when molding, and even a three-dimensional blade such as the blade 44 of this embodiment can be used. It is easy to make the hollow portion S sufficiently large. Thereby, the formation of the hollow member of the blade 44 can be promoted, and the impeller 42 can be reduced as much as possible.

  As described above, peeling is particularly likely to occur on the suction surface side of such a blade 44, and generally the noise on the suction surface side is higher than that on the pressure surface side. Therefore, as shown in FIGS. 6 and 7, in this embodiment, a large number of small holes 70, 70... Penetrating into the space in the hollow portion S are provided on the negative pressure surface 44f side of the blade 44. Such high noise is effectively absorbed.

  As described above, if the suction surface of each blade 44, 44... Is provided with a large number of small holes 70, 70... Penetrating into the hollow portion S in each blade 44, 44. The noise generated on the suction surface 44f side of each blade 44, 44... Enters each small hole 70, 70... And the Helmholtz resonance is caused by the air layer in the hollow portion S inside each blade 44, 44. Occurs, noise having the same frequency as the resonance frequency is absorbed, and the noise of the fan is effectively reduced.

  In this case, it is preferable that the small holes 70, 70... Are arranged in a fixed relationship with a fixed pitch.

  In order to generate an effective Helmholtz resonance with the hollow portion S inside the blade 44, it is important that the pitch between the small holes 70, 70... It exhibits an effective noise absorbing action when it is kept in place.

  Moreover, it is preferable that the diameter of each said small hole 70,70 ... is a diameter of the range which does not exceed 3 mm.

  When the diameter of the small holes 70, 70... Is 3 mm or more, noise generated by the holes themselves due to the edge of the small hole neck becomes high, and a low noise effect cannot be obtained.

  Therefore, the diameter of the small holes 70, 70... Is preferably in a range not exceeding 3 mm.

  In addition to these, in forming the small holes 70, 70..., The depth of the air layer of the hollow portion S, the length of the neck of the hole determined by the plate thickness, the diameter of the hole, The distance between the holes, the ratio of the total area of the holes to the blade surface area of the blade 44, etc. are set so that the Helmholtz resonance absorption mechanism functions most effectively.

(4) Operation | movement of an air conditioning apparatus Next, operation | movement of the air conditioning apparatus 1 comprised as mentioned above is demonstrated.

  Now, when the operation of the air conditioner 1 is started, the fan motor 41 is driven and the impeller 42 of the blower 4 rotates. In addition, as the fan motor 41 is driven, refrigerant is supplied into the heat exchanger 6 from an outdoor unit (not shown). Here, the heat exchanger 6 acts as an evaporator during the cooling operation and as a condenser during the heating operation.

  With the rotation of the impeller 42, the air in the air-conditioned room is sucked from the lower side of the blower 4 through the filter 34 and the bell mouth 5 from the air suction port 31 of the decorative panel 3. The sucked air is blown out to the outer peripheral side by the impeller 42 and reaches the heat exchanger 6. After being cooled or heated in the heat exchanger 6, the sucked air is blown out into the air-conditioned room through the plurality of air outlets 32. The In this way, cooling or heating in the air-conditioned room is performed.

  Here, for example, as shown in FIG. 4, the impeller 42 rotates in the direction of the arrow R, so that centrifugal force acts on the plurality of blades 44. The blade 44 made of hollow blades according to the present embodiment has a blade body 51 fixed to the end plate 43 and the end ring 45, and a part of the suction surface 44f of the blade 44 (specifically, the rear edge portion of the suction surface 44f). Since the blade lid 61 arranged so as to constitute a portion of the blade main body 51 is mounted, the blade lid 61 mounted on the blade body 51 is lifted by the centrifugal force and the blade 44 is deformed. It is possible to prevent. Thereby, troubles, such as a squeak and a wind noise of the impeller 42, are less likely to occur, and the blower performance and noise performance of the blower 4 or the air conditioner 1 as a whole can be improved.

  In addition, the blade lid 61 is arranged so as to constitute a part of the negative pressure surface 44f of the blade 44 so as to prevent the blade lid 61 from being lifted by the centrifugal force. However, since the blade shape holding mechanism described above is provided, deformation of each part of the blade lid 61 toward the blade body 51 side is suppressed, and the shape of the blade 44 is held.

  In addition, since many small holes 70, 70... Of the Helmholtz resonance absorption method are provided on the suction surface 44f side of the blade 44, noise due to air separation on the suction surface 44f side of the blade 44 is also effectively reduced. .

(5) Features of the centrifugal fan impeller and the centrifugal fan provided with the centrifugal fan The impeller 42 of the centrifugal fan 4 employed in the air conditioner 1 of the present embodiment and the centrifugal fan 4 provided with There are such features.

  That is, in the impeller 42 of the centrifugal blower 4 of the present embodiment, since the plurality of blades 44 are constituted by the blade body 51 and the blade lid 61 attached to the blade body 51 as described above, the blade 44 is the end. Even a three-dimensional wing that extends in the axial direction while twisting between the plate 43 and the end ring 45 can promote hollowing of the blade 44 and reduce the impeller 42 as much as possible.

  Moreover, since the blade lid 61 is attached to the blade body 51 by fitting, the assembly of the blade 44 is easy.

  Of the blade body 51 and the blade lid 61, the blade body 51 is fixed to the end plate 43, and the blade lid 61 is attached to a part of the negative pressure surface 44f of the blade 44 (specifically, the rear edge portion of the negative pressure surface 44f). (Excluding part) is arranged. In other words, the blade lid 61 is arranged so that the state of being attached to the blade body 51 is maintained even if a centrifugal force due to the rotation of the end plate 43 is applied to the blade lid 61.

  Therefore, it is possible to prevent the blade lid 61 mounted on the blade body 51 from being lifted by the centrifugal force and causing the blade 44 to be deformed, so that problems such as squeaks and wind noise are less likely to occur. In particular, in the blade 44 assembled by fitting the blade lid 61 into the blade body 51 as in this embodiment, there is no problem that the blade lid 61 comes off due to centrifugal force.

  Further, as a result of arranging the blade lid 61 so as to constitute a part of the negative pressure surface 44f of the blade 44 to prevent the blade lid 61 from being lifted by centrifugal force, the blade lid 61 is directed in the direction of the blade body 51 with respect to the blade lid 61. Although a load is applied, since the blade shape holding mechanism is provided, the shape of the blade 44 is held by suppressing the deformation of each part of the blade lid 61 toward the blade body 51 side. As a result, problems such as squeak and wind noise of the blade 44 are further less likely to occur.

  Further, in the impeller of the multiblade centrifugal blower in which the inside of the main body of a large number of blades 44, 44... Is hollow, the blades 44, 44. Since a large number of small holes 70, 70... Penetrating through the hollow portion S in the blades 44, 44... Are provided, noise generated on the negative pressure surface 44f side of the blades 44, 44. 70, 70..., Helmholtz resonance is generated by the air layer of the hollow portion S, and noise having the same frequency as the resonance frequency is absorbed, and noise due to separation on the suction surface 44f side is reliably reduced. Is done.

  As described above, in the centrifugal blower 4 of the present embodiment, the hollowness of the blade 44 is promoted to reduce the weight, the deformation of the blade 44 is suppressed, and defects such as stains and wind noise are less likely to occur. Since the impeller 42 that also absorbs noise due to separation on the negative pressure surface 44f side is provided, the air blowing performance and the silent performance can be improved more effectively.

  In the impeller 42 of the centrifugal blower 4, the plurality of blade main bodies 51, the end plate 43, and the end ring 45 are separate members. Therefore, the blade main body 51 constituting the blade 44, the end plate 43, The end ring 45 can be easily formed.

(Modification 1)
By the way, when the blade 44 is assembled as described above, the large hollow portion S as described above is formed between the blade main body 51 and the blade lid 61, so that the blade main body 51 is directed toward the blade lid 61. When the load is applied, the blade lid 61 tends to deform toward the blade body 51 as it is.

  Therefore, in the blade 44 of the present embodiment, as a countermeasure, a reinforcing structure as shown in FIG. 8 is also adopted as necessary. When a load in the direction of the blade body 51 is applied to the blade lid 61, the blade lid 61 A blade shape holding mechanism is provided for holding the original appropriate shape of the blade 44 by suppressing the deformation of the respective portions to the blade body 51 side.

  That is, protrusions 72, 72,... Are provided at appropriate intervals inside the blade body 51, and the blade lid 61 is supported by these protrusions 72, 72, so that the blade body 51 is not deformed. To be.

  Further, the rear edge portion of the blade lid 61 is configured such that the rear edge side edge portion 64 of the blade lid 61 is brought into contact with the end surface on the blade lid 61 side of the rear edge 54 side contact portion 54a of the blade body 51. It is held so as not to be deformed. Further, the front edge portion of the blade lid 61 is brought closer to the blade body 51 side by bringing the front edge side edge portion of the blade lid 61 into contact with the end surface of the front edge 55 side abutting portion 55a of the blade body 51 on the blade lid 61 side. It is held so as not to deform.

(Modification 2)
In addition to the above configuration, separation may occur on the positive pressure surface 44e side of each blade 44, resulting in noise. In such a case, for example, as shown in FIG. 9, small holes 70, 70... Penetrating into the hollow portion S in the blade 44 are provided on the pressure surface 44 e side of the blade 44. Noise can be effectively absorbed.

  When the small holes 70, 70... Penetrating into the blades 44, 44... Are provided on the positive pressure surfaces 44e, 44e. The noise generated on the pressure surface 44e, 44e ... side of the blades 44, 44 ... enters the small holes 70, 70 ..., and Helmholtz resonance is generated by the air layer of the hollow portion S inside. Noise of the same frequency as the frequency is absorbed, and fan noise is reduced.

(Modification 3)
Further, separation may occur on the negative pressure surface 44f side and the positive pressure surface 44e side of each blade 44, 44. In such a case, for example, as shown in FIG. 10, the hollow portions S in the blades 44, 44... Are similarly formed on the positive pressure surface 44e side and the negative pressure surface 44f side of the blades 44, 44. It is also possible to provide small holes 70, 70... Penetrating inside to effectively absorb such noise.

  In this case, it is more effective if the small holes 70, 70..., 70, 70... On the negative pressure surface 44f side and the positive pressure surface 44e side are provided so as not to face each other. .

BRIEF DESCRIPTION OF THE DRAWINGS It is an external appearance perspective view of the air conditioning apparatus by which the impeller of the centrifugal fan concerning the best embodiment of this invention and the centrifugal fan provided with the same were employ | adopted. It is sectional drawing of the air conditioning apparatus. It is a perspective view of the impeller of the said centrifugal blower. FIG. 4 is a view in the direction of arrow A of the impeller of FIG. 3 (illustrated excluding a part of the end ring). It is a side view of the blade part of the impeller of FIG. It is BB sectional drawing of FIG. It is CC sectional drawing of FIG. It is sectional drawing of the structure which concerns on the modification 1 of a blade part. It is sectional drawing of the structure which concerns on the modification 2 of a blade part. It is sectional drawing of the structure which concerns on the modification 3 of a blade part.

Explanation of symbols

  4 is a centrifugal blower, 41 is a fan motor, 41a is a shaft (rotary shaft), 42 is an impeller, 43 is an end plate (main plate), 44 is a blade (hollow blade), 44e is a positive pressure surface, 44f is a negative pressure surface, 45 Is an end ring (side plate), 51 is a blade body (first surface portion), 61 is a blade lid (second surface portion), 70 is a small hole, and S is a hollow portion.

Claims (6)

  In an impeller of a centrifugal blower in which each blade of a plurality of blades is hollow, a large number of small holes that penetrate the hollow portions in each blade are provided on the suction surface side of each blade. Centrifugal blower impeller.   In an impeller of a centrifugal blower in which each blade of a plurality of blades is hollow, a large number of small holes that penetrate the hollow portions in each blade are provided on the pressure surface side of each blade. Centrifugal blower impeller.   In an impeller of a centrifugal blower in which each blade of a plurality of blades is hollow, a plurality of small holes that penetrate the hollow portion in each blade are provided on each of the pressure surface side and the suction surface side of each blade. An impeller of a centrifugal blower characterized by being   4. The impeller of a centrifugal blower according to claim 1, wherein each of the small holes is arranged in a fixed relation with a fixed pitch.   The impeller of the centrifugal fan according to claim 1, 2, 3, or 4, wherein each small hole has a diameter not exceeding 3 mm.   6. The impeller of a centrifugal blower according to claim 1, wherein the impeller is configured as an impeller for a blower of an indoor unit for an air conditioner.

Images