JP5754210B2 - Centrifugal blower and air conditioner equipped with the same - Google Patents

Description

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

  Conventionally, a centrifugal blower such as a turbo fan has been used as a blower of an air conditioner. This centrifugal blower includes an impeller fixed to a rotation shaft of a fan motor and a bell mouth. The impeller includes a shroud having an air suction end that opens in a circular shape, and a plurality of blades arranged on the inner surface of the shroud along the circumferential direction of the shroud and fixed to the shroud. The bell mouth has an air outflow end portion that opens in a circular shape, and the air outflow end portion is inserted into the opening of the air intake end portion with a predetermined gap between the air outflow end portion and the air intake end portion of the shroud. ing.

  In such a centrifugal blower, when the impeller rotates, air is guided in the axial direction along the bell mouth and guided to the shroud, and flows out from the impeller radially outward through the blades. Most of the air that flows out is blown out from the air outlet provided in the case of the air conditioner, but some of the air circulates inside the case and reaches the gap between the shroud and the bell mouth. Then, it flows again into the shroud from this gap. As a result, the re-inflowing air flow (leakage flow) interferes with the air flow (main flow) guided in the axial direction along the bell mouth and guided to the shroud, and noise is likely to occur.

  Therefore, Patent Literature 1 proposes a centrifugal blower in which a cylindrical airflow resistance portion is provided so as to surround the air suction end portion of the shroud and the air outflow end portion of the bell mouth from the outside. In this centrifugal blower, the amount of leakage flow is reduced by the airflow resistance portion and the leakage flow is rectified, so that noise is reduced.

JP 2010-209909 A

  By the way, since the airflow resistance part in the centrifugal blower described in Patent Document 1 has a three-dimensional cylindrical shape, the airflow resistance part is bulky during transportation and storage, leading to an increase in transportation cost and an increase in storage space. And the problem of these transportation costs and storage space leads to the cost increase of a centrifugal blower as a result.

  Therefore, the present invention has been made in view of such a point, and the object of the present invention is to provide a centrifugal blower that can reduce noise caused by leakage flow, and that can suppress an increase in transportation cost and storage space, and the centrifugal blower. The object is to provide an air conditioner equipped.

(1) The centrifugal blower of the present invention includes an impeller (17), a bell mouth (6), and an airflow resistance unit (20). The impeller (17) is arranged on the inner surface of the shroud (15) along the circumferential direction of the shroud (15), the shroud (15) having an air suction end (15a) opening in a circular shape, A plurality of blades (16) fixed to the shroud (15). The bell mouth (6) has an air outflow end (6c) that opens in a circular shape. The air outflow end (6c) is inserted into the opening of the air suction end (15a) in a state where a predetermined gap is provided between the air outflow end (6c) and the air suction end (15a). The airflow resistance portion (20) is disposed so as to surround the air suction end portion (15a) and the air outflow end portion (6c) from the outside, and a plurality of holes are provided over substantially the whole. The airflow resistance portion (20) includes a rectangular sheet-like porous body (21) having a first side (21a) and a second side (21b) facing each other, and the first side (21a) and the second side ( 21b) is arranged in a state of being rounded into a cylindrical shape so as to be connected to each other, and the first side (21a) and the second side (21b) are not bonded .

  In this configuration, the airflow resistance portion (20) provided with a plurality of holes over substantially the entire portion is provided so as to surround the air suction end portion (15a) and the air outflow end portion (6c) from the outside. Noise caused by (circulation flow) can be reduced.

  In addition, the airflow resistance portion (20) includes a rectangular sheet-like porous body (21) having a first side (21a) and a second side (21b) facing each other, the first side (21a) and the second side ( 21b) are arranged in a state of being rounded into a cylindrical shape so as to be connected to each other. That is, the sheet-like porous body (21) becomes a three-dimensional cylindrical shape only when it is rounded so that the first side (21a) and the second side (21b) are connected to each other. The front has a planar shape. Therefore, since the sheet-like porous body (21) is not bulky during transportation or storage, an increase in transportation cost and storage space can be suppressed.

(2) In the centrifugal blower, the sheet-like porous body (21) has a third side (21c) connecting ends of the first side (21a) and the second side (21b), A plurality of first engaging portions arranged along the third side (21c), and the bell mouth (6) has a plurality of second engaging portions arranged along the circumferential direction; the sheet-like porous body (21), by engaging said second engaging portion corresponding to the first engaging portion, wherein for the bell mouth (6) Ru removably secured.

  (3) In the centrifugal blower, each first engagement portion is an engagement protrusion (51) protruding outward from the third side (21c), and each second engagement portion corresponds to the corresponding engagement The engagement hole (53) into which the protrusion (51) is inserted is preferable.

  Since the bell mouth usually has a three-dimensionally curved shape, a plurality of engaging protrusions (51) are formed on the sheet-like porous body (21) rather than providing a plurality of engaging protrusions (51) on the bell mouth. It is easier to form the engaging protrusion (51). On the other hand, the bell mouth only needs to be formed with a plurality of engagement holes (53) into which the engagement protrusions (51) are inserted. Thereby, productivity of a centrifugal blower improves.

  (4) In the centrifugal blower, the material constituting the sheet-like porous body (21) is preferably softer than the material constituting the bell mouth (6).

  In this configuration, since the material constituting the sheet-like porous body (21) is softer than the material constituting the bell mouth (6), the sheet-like porous body (21) is easily rolled into a desired cylindrical shape. Can do. Thereby, workability when fixing the sheet-like porous body (21) to the inner surface of the bell mouth (6) is improved.

  (5) The air conditioner of the present invention includes the centrifugal blower.

  As described above, according to the present invention, it is possible to reduce noise due to leakage flow, and to suppress an increase in transportation cost and storage space.

It is sectional drawing which shows the ceiling embedded type air conditioner provided with the centrifugal blower which concerns on one Embodiment of this invention. It is a bottom view which shows the said air conditioner. It is a side view which shows the sheet-like porous body for forming the airflow resistance part of the said centrifugal blower. It is a perspective view which shows the state before attaching the said sheet-like porous body to the bell mouth of the said centrifugal blower. It is a perspective view which shows the state which attached the said sheet-like porous body to the bell mouth of the said centrifugal blower. It is sectional drawing which shows the state which the engagement protrusion of the said sheet-like porous body engaged with the engagement hole of the said bellmouth. It is an expanded sectional view which shows the flow of the air in the said centrifugal blower. It is sectional drawing which shows the modification of the air conditioner provided with the said centrifugal blower. It is an expanded sectional view which shows the flow of the air in the centrifugal blower in the air conditioner of a modification.

  Hereinafter, a centrifugal blower 11 according to an embodiment of the present invention and an air conditioner 1 including the centrifugal blower 11 will be described in detail with reference to the drawings.

<Overall structure of air conditioner>
As shown in FIG. 1, the air conditioner 1 is a ceiling-embedded indoor unit, and is a flat panel type indoor unit in which a grill is not provided on the lower surface panel 4 constituting the lower surface. The air conditioner 1 includes a box-shaped case 2, a centrifugal blower 11, a fan motor 13, and a heat exchanger 12.

  The case 2 is embedded in the ceiling 3 so that the lower surface panel 4 forms substantially the same plane as the ceiling 3. As shown in FIG. 2, the lower panel 4 has a rectangular shape. The lower surface panel 4 has four air outlets 9 that are elongated along the periphery thereof, and an air inlet 41 that opens in a rectangular ring shape inside the air outlets 9.

  The lower panel 4 has a flat panel portion 42 at the center thereof. The flat panel portion 42 has a flat bottom surface, and is not formed with a grill as shown in a modified example shown in FIG. Therefore, the flat panel portion 42 does not function as an air inlet. The peripheral edge of the flat panel portion 42 constitutes the inner peripheral edge of the air suction port 41. Above the lower panel 4, a filter 45 is disposed along the upper surface of the lower panel 4 so as to cover at least the air suction port 41.

  The fan motor 13 is attached to the approximate center of the top plate 2 a of the case 2. The fan motor 13 has a rotating shaft 13a extending downward. The centrifugal blower 11 is disposed above the lower panel 4 and the filter 45. The heat exchanger 12 is provided in the case 2 so as to surround the outside of the centrifugal blower 11, and is located inside the four air outlets 9 and outside the air inlet 41 in a bottom view. The heat exchanger 12 is placed on the upper surface of the drain pan 18.

<Structure of centrifugal blower>
The centrifugal blower 11 includes a bell mouth 6, an impeller 17, and an airflow resistance unit 20. The impeller 17 includes a circular hub 14 in a bottom view, a circular shroud 15 in a bottom view, and a plurality of blades 16 arranged therebetween. The centrifugal blower 11 is a turbo fan in which each blade 16 is a backward blade. In the case 2, the fan motor 13, the hub 14, the plurality of blades 16, the shroud 15, and the bell mouth 6 are arranged in this order from the back side (upper side) R to the front side (lower side) F. A lower end portion of the rotation shaft 13 a of the fan motor 13 is fixed to the hub 14.

  The shroud 15 has an air suction end 15a that opens in a circle around the rotation shaft 13a (a straight line passing through the rotation shaft 13a). The shroud 15 has a shape in which the inner diameter increases from the front side F toward the back side R. The plurality of blades 16 are arranged at predetermined intervals along the circumferential direction between the shroud 15 and the hub 14. The upper end of each blade 16 is fixed to the lower surface of the hub 14, and the lower end is fixed to the upper surface of the shroud 15.

  The bell mouth 6 is disposed so as to face the upper surface of the lower panel 4. The bell mouth 6 has a flange portion 6 a fixed to the lower surface panel 4, an air inflow portion 6 b, and an air outflow end portion 6 c located at an end portion on the rear side R. The flange portion 6a projects in a flange shape outward from the air inflow portion 6b in the radial direction. The air inflow portion 6b and the air outflow end portion 6c are opened in a circle around the rotation shaft 13a (a straight line passing through the rotation shaft 13a), and form a guide surface that guides air to the impeller 17. The air inflow portion 6b has a shape in which the inner diameter decreases from the front side F toward the back side R.

  The air outflow end portion 6c of the bell mouth 6 is inserted into the opening of the air suction end portion 15a with a predetermined size in a state where a predetermined gap G is provided between the air outflow end portion 15a of the shroud 15. Thereby, the air sucked into the case 2 from the air suction port 41 flows along the bell mouth 6 to the rear side R, and smoothly flows into the impeller 17 through the air suction end 15 a of the shroud 15.

<Structure of airflow resistance part>
As shown in FIG. 1, the airflow resistance portion 20 has a cylindrical shape, and is disposed so as to surround the air suction end portion 15a and the air outflow end portion 6c from the outside. That is, the airflow resistance unit 20 is disposed so as to surround the gap G from which the leakage flow re-inflows from the outside. The airflow resistance portion 20 is attached to the bell mouth 6 with the end portion (periphery) of the front side F in contact with or close to the inner surface (upper surface) of the flange portion 6 a of the bell mouth 6.

  The airflow resistance portion 20 extends in a cylindrical shape from the inner surface of the flange portion 6 a toward the outer surface (lower surface) of the shroud 15. The end (periphery) on the back surface side R of the airflow resistance unit 20 is in a position close to the outer surface of the shroud 15, and a predetermined gap is formed from the outer surface of the shroud 15 so as not to contact (interfere) with the rotating shroud 15. Are arranged. The outer diameter of the airflow resistance portion 20 is approximately the same as the outer diameter of the peripheral edge portion 15 b on the back side R of the shroud 15.

  The airflow resistance portion 20 has a net-like structure, and a plurality of substantially uniform holes are provided over substantially the whole. The opening size and opening shape of the plurality of holes are not particularly limited. In the airflow resistance portion 20 in the present embodiment, a plurality of rectangular openings are formed by a large number of thin lines arranged vertically and horizontally at predetermined intervals.

  The airflow resistance portion 20 is not integrally formed with the bell mouth 6 but is formed separately from the bell mouth 6. The airflow resistance part 20 is attached to the inner surface of the bell mouth 6 in a state where the sheet-like porous body 21 shown in FIG. 3 is rolled into a cylindrical shape as shown in FIG.

  The sheet-like porous body 21 has a rectangular shape that is long in one direction. The sheet-like porous body 21 includes a first side 21a located at one end in the longitudinal direction, a second side 21b facing the first side 21a in the longitudinal direction, an upper end of the first side 21a, and a second side 21b. And a fourth side 21d connecting the lower end of the first side 21a and the lower end of the second side 21b.

In the state where the sheet-like porous body 21 is attached to the bell mouth 6, as shown in FIG. 4, the sheet-like porous body 21 is rolled into a cylindrical shape so that the first side 21a and the second side 21b are connected. Be placed. Here, "the first side 21a and the second side 21b are connected" means not only the case where the first side 21a and the second side 21b are arranged to face each other, but also as shown in FIG. This includes the case where the first side 21 a and the area in the vicinity thereof and the second side 21 b and the area in the vicinity thereof are arranged so as to overlap in the thickness direction of the sheet-like porous body 21. The first side 21a and the second side 21b are not bonded.

  As shown in FIG. 3, the sheet-like porous body 21 includes a plurality of vertical line portions 21e parallel to the first side 21a and the second side 21b, and a horizontal line portion 21f parallel to the third side 21c and the fourth side 21d. It has further. The plurality of vertical line portions 21e are arranged at substantially equal intervals between the first side 21a and the second side 21b. The horizontal line portion 21f is located between the third side 21c and the fourth side 21d. The plurality of vertical line portions 21e and horizontal line portions 21f have outer diameters larger than the fine lines forming the net-like portions 21g which are portions other than the vertical line portions 21e and the horizontal line portions 21f, and are sheet-like porous. The function of increasing the rigidity of the body 21 is achieved. In addition, when it becomes independent only with the mesh part 21g, the vertical line part 21e and the horizontal line part 21f can also be abbreviate | omitted.

  The sheet-like porous body 21 has a plurality of engaging protrusions (first engaging portions) 51 arranged along the third side 21c. Each engagement protrusion 51 is provided so as to protrude upward from the upper end of the vertical line portion 21e. As shown in FIG. 4, the bell mouth 6 has a plurality of engagement holes (second engagement portions) 53 arranged in a ring shape along the circumferential direction. As shown in FIG. 5, the sheet-like porous body 21 is fixed to the bell mouth 6 by engaging each engagement protrusion 51 with the corresponding engagement hole 53. In addition, each engagement protrusion 51 does not necessarily need to be provided in the upper end position of the vertical line part 21e.

  As shown in FIG. 6, each engaging protrusion 51 has an extending part 51a extending upward from the third side 21c and a locking part 51b connected to the upper end of the extending part 51a. The outer diameter of the extending part 51a is substantially constant in the extending direction. The outer diameter of the latching | locking part 51b becomes small as it goes to an upper end from the lower end connected to the extension part 51a. That is, the locking part 51b has a tapered shape. The outer diameter of the lower end of the locking part 51 b is larger than the outer diameter of the extension part 51 a and larger than the inner diameter of the engagement hole 53.

  Each engaging protrusion 51 is formed with one or a plurality of slits parallel to the vertical direction (extending direction of the extending part 51a), and the extending part 51a and the locking part 51b are formed by the slits. It is divided into divided pieces. The outer diameter of the lower end of the locking portion 51b can be made smaller than the inner diameter of the engagement hole 53 by bending and deforming the plurality of divided pieces in the direction of reducing the gap between the divided pieces. The mating protrusions 51 are inserted into the corresponding engagement holes 53. Then, after the insertion, the plurality of divided pieces return to their original state before being deformed, whereby the respective engagement protrusions 51 are engaged with the corresponding engagement holes 53. By performing the reverse operation, the sheet-like porous body 21 can be removed from the bell mouth 6.

  The material constituting the sheet-like porous body 21 is preferably softer than the material constituting the bell mouth 6. The bell mouth 6 is required to maintain a predetermined shape that is difficult to be deformed during use. On the other hand, the sheet-like porous body 21 is molded and fixed separately from the bell mouth 6, so Also, a soft material can be used. When the material of the sheet-like porous body 21 is softer than the material of the bell mouth 6, the sheet-like porous body 21 can be easily deformed into a cylindrical shape, so that the work for attaching to the bell mouth 6 is facilitated.

  Specifically, for example, a hard synthetic resin such as acrylonitrile-butadiene-styrene copolymer (ABS) is used as the material of the bell mouth 6, and a soft synthetic resin such as polypropylene is used as the material of the sheet-like porous body 21. be able to. Moreover, you may form both the bell mouth 6 and the sheet-like porous body 21 with a metal. Further, a metal can be used as the material of the bell mouth 6, and a synthetic resin can be used as the material of the sheet-like porous body 21.

  The sheet-like porous body 21 can be produced by using a joining method such as forming the mesh portion 21g and a portion other than the mesh portion 21g separately and then welding them with heat. Moreover, the sheet-like porous body 21 can also be integrally molded using a molding method such as injection molding.

  Next, the flow of air in the air conditioner 1 will be described with reference to FIG. When current is supplied to the fan motor 13 and the rotating shaft 13a rotates, the impeller 17 rotates accordingly. As a result, air is sucked into the case 2 through the air suction port 41. The sucked air is guided by the bell mouth 6 and flows into the shroud 15, passes between the blades 16, and flows out from the impeller 17 radially outward. The air that has flowed out is subjected to heat exchange in the heat exchanger 12 and then blown out into the room from the air outlet 9. A part of the air that has flowed radially outward from the impeller 17 circulates in the case 2 toward the bell mouth 6 as shown in FIG. 7, and leaks from the gap between the bell mouth 6 and the shroud 15 as a leak flow B. Re-enters 17.

  In the present embodiment, since the airflow resistance portion 20 having a cylindrical shape and provided with a plurality of substantially uniform holes over substantially the whole is disposed on the path of the leakage flow B, the leakage flow B is the gap Passes through the airflow resistance portion 20 before reflowing into the impeller 17. At this time, since the airflow resistance portion 20 becomes the resistance of the leakage flow B, the amount of the leakage flow B can be reduced as compared with the case where the airflow resistance portion 20 is not provided. Moreover, since the airflow resistance section 20 is provided with substantially uniform holes throughout the entire area, the airflow turbulence can be suppressed by rectifying the leakage flow B. As described above, the amount of the leakage flow B is reduced, and the disturbance of the leakage flow B is suppressed, whereby noise can be reduced. In addition, an effect of reducing the input to the motor can be expected, and energy saving can be achieved.

(Modification)
FIG. 8 is a cross-sectional view illustrating a modification of the air conditioner 1 including the centrifugal blower 11. FIG. 9 is an enlarged cross-sectional view showing the flow of air in the centrifugal blower 11 in the air conditioner 1 of this modification. The air conditioner 1 of this modification is different from the air conditioner 1 shown in FIG. 1 in that a grill 5 is provided on the lower panel 4 and that the entire grill 5 functions as an air suction port 41. ing.

  As shown in FIG. 9, in the air conditioner 1 of this modified example, the air suction port 41 is formed in a region facing almost the entire region of the bell mouth 6 as compared to the air conditioner 1 shown in FIG. 1. The resistance when air flows into the case 2 is small, and a relatively stable airflow is obtained. In other words, in the air conditioner 1 shown in FIG. 1, since the air suction port 41 is relatively small and is provided at a position biased toward the peripheral edge, the air suction port 41 flows from the air suction port 41 and flows out from the impeller 17. The air flow tends to be greatly curved and unstable, and accordingly, the disturbance of the leakage flow B tends to increase. As a result, in the air conditioner 1 shown in FIG. 1, the noise tends to be larger than that of the air conditioner 1 of the modification shown in FIG.

  Therefore, the noise reduction effect by providing the airflow resistance unit 20 is more prominent in the air conditioner 1 shown in FIG. 1 than in the air conditioner 1 shown in FIG.

<Outline of Embodiment>
The above embodiment is summarized as follows.

  In the present embodiment, since the airflow resistance portion 20 having a plurality of holes provided over substantially the entire portion is provided so as to surround the air suction end portion 15a and the air outflow end portion 6c from the outside, noise caused by the leakage flow is reduced. Can be reduced.

  Moreover, the airflow resistance portion 20 is arranged in a state where a rectangular sheet-like porous body having a first side and a second side facing each other is rounded into a cylindrical shape so that the first side and the second side are connected. It is a thing. That is, the sheet-like porous body has a three-dimensional cylindrical shape only after being rounded so that the first side and the second side are connected, and has a planar shape before being rounded in this way. ing. Therefore, since the said sheet-like porous body is not bulky at the time of transportation or storage, an increase in transportation cost and storage space can be suppressed.

  In the present embodiment, each first engagement portion is an engagement protrusion that protrudes outward from the third side, and each second engagement portion is an engagement hole into which the corresponding engagement protrusion is inserted. is there. Since the bell mouth usually has a three-dimensionally curved shape, it is easier to provide a plurality of engaging protrusions on the sheet-like porous body 21 than to provide a plurality of engaging protrusions on the bell mouth 6. Joint protrusions can be formed. On the other hand, the bell mouth only needs to be formed with a plurality of engagement holes into which the engagement protrusions are inserted.

  Further, in the present embodiment, since the engaging protrusion 51 is engaged with the engaging hole 53, the mounting of the sheet-like porous body 21 on the bell mouth 6 is easy. Furthermore, in this embodiment, for example, during the maintenance such as cleaning the airflow resistance portion 20, the removal work and the reattachment work of the sheet-like porous body 21 are simple.

  In this embodiment, since the material constituting the porous body is softer than the material constituting the bell mouth 6, it can be easily rounded into a desired cylindrical shape, and the porous body is fixed to the inner surface of the bell mouth 6. Excellent workability when.

<Other embodiments>
As mentioned above, although each 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 embodiment, the case where the engagement protrusion 51 provided on the sheet-like porous body 21 is engaged with the engagement hole 53 provided on the bell mouth 6 is exemplified. It can also be attached to the bell mouth 6 by other methods such as fastening or fusing.

  In the said embodiment, although the case where the several hole of the airflow resistance part 20 was substantially uniform was illustrated, all the several holes do not necessarily need to be the same opening dimension. However, it is preferable that the plurality of holes have the same opening size and the same opening shape in terms of more uniformly rectifying the airflow over the entire airflow resistance portion 20.

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

DESCRIPTION OF SYMBOLS 1 Air conditioner 2 Case 6 Bell mouth 6c Air outlet part 11 Centrifugal blower 13 Fan motor 14 Hub 15 Shroud 15a Air suction end 16 Blade 17 Impeller 20 Airflow resistance part 21 Sheet-like porous body 51 Engaging protrusion 53 Engage Hole

Claims (4)

A shroud (15) having an air suction end (15a) opening in a circular shape, and arranged on the inner surface of the shroud (15) along the circumferential direction of the shroud (15), and fixed to the shroud (15) An impeller (17) including a plurality of blades (16);
It has an air outflow end (6c) that opens in a circular shape, and the air outflow end (6c) is provided with a predetermined gap between the air outflow end (6c) and the air intake end (15a) ( A bell mouth (6) inserted into the opening of 15a),
The air suction end portion (15a) and the air outflow end portion (6c) are arranged so as to surround from the outside, and the airflow resistance portion (20) provided with a plurality of holes substantially over the whole, and comprises:
The airflow resistance portion (20) includes a rectangular sheet-like porous body having a first side (21a) and a second side (21b) facing each other, and the first side (21a) and the second side (21b). der and which first side (21a) and the second side and is (21b) arranged in a state that is not adhered in a state rounded into a cylindrical shape as lead is,
The sheet-like porous body has a third side (21c) that connects the end portions of the first side (21a) and the second side (21b), and a plurality of the porous sheets arranged along the third side (21c). Having a first engaging portion,
The bell mouth (6) has a plurality of second engaging portions arranged along the circumferential direction,
The centrifugal blower, wherein the sheet-like porous body is detachably fixed to the bell mouth (6) by engaging each first engaging portion with the corresponding second engaging portion . Each first engagement portion is an engagement protrusion (51) protruding outward from the third side (21c),
The centrifugal blower according to claim 1 , wherein each second engagement portion is an engagement hole (53) into which the corresponding engagement protrusion (51) is inserted. The centrifugal blower according to claim 1 or 2 , wherein a material constituting the sheet-like porous body is softer than a material constituting the bell mouth (6). The air conditioner provided with the centrifugal blower of any one of Claims 1-3 .

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