JP2019167939A - Air blower and indoor unit of air conditioner - Google Patents

Abstract

To provide an air blower having an impeller preventing a sink mark.SOLUTION: An air blower is provided with an impeller. The impeller comprises a main plate including a boss part fixed to a revolving shaft of a motor and several through-holes enclosing the boss part, a shroud oppositely arranged against the main plate and several blades formed integral with the main plate by synthetic resin between the main plate and the shroud, having inside part communicated with the through-holes and including a recess concave from the main plate side to the shroud side. The blades have a twisted shape in an axial direction of the revolving shaft from the main plate side to the shroud side, and in an area from a front edge to a rear edge, an area from the front edge to the thickest part where at least a thickness becomes thickest is inclined from a positive pressure surface to a negative pressure surface as it goes from the main plate side to the shroud side, and a thickness of the thickest part is set to a range from 15% to 25% of a chord length from the front edge part to the rear edge part at an interface plane with the main plate.SELECTED DRAWING: Figure 8

Description

  Embodiments described herein relate generally to an indoor unit of a blower and an air conditioner.

  The ceiling-embedded indoor unit that is suspended from the back of the ceiling is equipped with a blower that blows air that has been heat-exchanged by a heat exchanger into the room. An impeller used for this type of blower includes a main plate connected to a rotating shaft of a motor, a ring-shaped shroud facing the main plate, and a plurality of blades interposed between the main plate and the shroud. As prepared.

  In a conventional impeller, a main plate and a blade are integrally formed by injection molding, and the blade is formed in a hollow shape opened toward the main plate in order to reduce the weight of the impeller.

JP 2005-155510 A

  The conventional impeller may not satisfy the dimensional tolerance of the outer shape when sink marks occur on the blade surface during injection molding. In this case, the blower equipped with the impeller and the indoor unit of the air conditioner equipped with the blower may not satisfy the expected performance.

  The objective of this invention is obtaining the air blower provided with the impeller which suppressed sink marks.

  According to the embodiment, the blower includes an impeller. The impeller includes a main plate having a boss portion attached to a rotating shaft of a motor and a plurality of through holes surrounding the boss portion, a shroud disposed to face the main plate, and the main plate and the shroud. And a plurality of blades that are formed integrally with the main plate with a synthetic resin therebetween and that communicate with the through-holes and that include recesses that are recessed from the main plate side to the shroud side.

  The blade has a shape twisted in the axial direction of the rotating shaft from the main plate side to the shroud side, and has a thickness that is at least maximum from the front edge portion in a region from the front edge portion to the rear edge portion. The region up to the thickest part is inclined from the pressure surface to the suction surface as it goes from the main plate side to the shroud side, and the thickness of the thickest portion is the front edge portion at the boundary surface with the main plate To 15% of the chord length from the rear edge to the rear edge.

FIG. 1 is a perspective view of a ceiling-embedded indoor unit used in an air conditioner. FIG. 2 is a cross-sectional view of a ceiling-embedded indoor unit. FIG. 3 is a perspective view of the impeller. FIG. 4 is a side view of the impeller. FIG. 5 is a bottom view of the impeller. FIG. 6 is a top view of the impeller. FIG. 7 is a side view of the blade. 8 is a bottom view taken along line F8-F8 in FIG. 9 is a cross-sectional view taken along line F9-F9 in FIG. FIG. 10A is a schematic diagram showing a blade in which the distance from the leading edge portion to the thickest portion is set to 15% to 30% of the chord length in the embodiment. FIG. 10B is a schematic diagram showing a blade in which the distance from the leading edge portion to the thickest portion is set to 14% or less of the chord length with respect to the proportionality 3. FIG. 10C is a schematic diagram showing a blade in which the distance from the leading edge portion to the thickest portion is set to 31% or more of the chord length with respect to the proportionality 4.

  Hereinafter, embodiments will be described with reference to the drawings.

  FIG. 1 is a perspective view of a ceiling-embedded indoor unit 1 used in an air conditioner, and FIG. 2 is a cross-sectional view of the indoor unit 1.

  As shown in FIGS. 1 and 2, the indoor unit 1 includes a main body 1a installed on the back of the ceiling and a decorative panel 2 attached to the lower end of the main body 1a as main elements. The main body 1a is inserted from an indoor side into an opening a provided in the ceiling c, and is suspended from a beam behind the ceiling via a plurality of suspension bolts (not shown).

  The main body 1a is a box-shaped element opened downward, and the blower 3 is disposed in the central portion inside the main body 1a. The blower 3 includes an impeller 5 driven by a motor 4. As the impeller 5, a so-called turbo fan that sucks air from the axial direction and discharges it in the circumferential direction is used. Since the upper end of the impeller 5 is covered with the top plate 1b of the main body 1a, the lower end of the impeller 5 is on the suction side.

  A heat exchanger 6 is disposed around the impeller 5 on the blowout side of the impeller 5. A drain pan 7 that receives drain water is disposed under the heat exchanger 6. A bell mouth 8 is attached to the inside of the drain pan 7. The bell mouth 8 constitutes a suction port 9 that faces the suction side of the impeller 5.

  The decorative panel 2 covers the lower end of the main body 1a from the room. The decorative panel 2 is exposed indoors from the lower surface of the ceiling c, and covers and hides the gap between the outer peripheral surface of the main body 1a and the opening a of the ceiling c.

  As shown in FIG. 1, the decorative panel 2 includes a suction grill 10 and a panel body 11. The suction grill 10 is provided at the center of the decorative panel 2 so as to face the suction port 9.

  The panel body 11 of the decorative panel 2 is formed in a square frame shape having four sides surrounding the suction grille 10, and is connected to the lower end of the body 1a. Furthermore, the panel main body 11 has four outlets 12. The air outlet 12 is an element that blows out the air heat-exchanged by the heat exchanger 6 in four directions of the decorative panel 2, and is provided on each of the four sides of the panel body 11.

  Flaps 13 are provided at the air outlets 12 of the panel body 11 to change the air blowing direction. The flap 13 is rotatably supported by the panel body 11.

  The air outlet 12 is closed by the flap 13 in a state where the operation of the air conditioner is stopped. When the air conditioner starts operation, the flap 13 rotates to a desired angle inside the air outlet 12, and the air outlet 12 is opened. Further, the blower 3 is driven, and the indoor air is sucked into the impeller 5 from the suction grill 10 through the suction port 9. The air sucked into the impeller 5 is discharged toward the heat exchanger 6 and heat exchanged with the refrigerant in the process of passing through the heat exchanger 6. The heat-exchanged air is guided from the air outlet 12 to the flap 13 and blown out into the room.

  The impeller 5 is a molded product obtained by injecting and injecting a heat-melted synthetic resin material into a mold and cooling and solidifying the material, and includes a main plate 21, a shroud 22, and a plurality of blades 23. Yes.

  As shown in FIGS. 3 to 6, the main plate 21 includes a support portion 21a formed in a disk shape. The support portion 21a supports the plurality of blades 23 concentrically. A boss portion 21b is provided at the center of the support portion 21a. The boss portion 21 b is attached to the rotating shaft 4 a of the motor 4. A plurality of through holes 21c are provided on the concentric circle of the support portion 21a so as to surround the boss portion 21b. The main plate 21 is injection-molded integrally with a plurality of blades 23.

  As shown in FIGS. 3 to 5, the shroud 22 is arranged to face the main plate 21 and covers the plurality of blades 23. The shroud 22 is formed in a ring shape and is inclined along the radial direction. The shroud 22 is joined to a protrusion 23g provided on the opposite side of the main plate 21 of the plurality of blades 23 by, for example, ultrasonic welding.

  The blade 23 is shown in FIGS. 3 to 9 and blows the air heat-exchanged by the heat exchanger 6 into the room. As shown in FIGS. 3 to 5, the blades 23 are interposed between the main plate 21 and the shroud 22 and are arranged at intervals in the circumferential direction of the impeller 5.

  As shown in FIGS. 6 to 9, the blade 23 has a wing shape and includes a recess 23 f that is recessed from the main plate 21 side to the shroud 22 side. The recess 23 f communicates with a through hole 21 c provided in the support portion 21 a of the main plate 21. The recess 23f is a portion where a mold for injection molding is inserted, and corresponds to so-called meat removal (meat stealing). With the configuration described later, the blade 23 can set the depth L2 of the recess 23f to 80% or more of the height (full length) L3, as shown in FIGS. That is, the blade 23 can sufficiently provide meat theft.

  As shown in FIG. 8, the blade 23 has a region B from the front edge portion 23a to the thickest portion 23c having the maximum thickness L1 in the region A from the front edge portion 23a to the rear edge portion 23b of the impeller 5. The pressure surface 23d is inclined from the positive pressure surface 23d toward the shroud 22 side from the main plate 21 side. The positive pressure surface 23 d of the blade 23 is a surface of the blade 23 located on the outer peripheral side of the impeller 5. The negative pressure surface 23 e of the blade 23 is a surface of the blade 23 located on the inner peripheral side of the impeller 5.

  With such a configuration, the blade 23 has a shape twisted in the axial direction of the four rotation shafts 4a of the motor from the main plate 21 side to the shroud 22 side. Specifically, a region C from the front edge 23a to the rear edge 23b in the portion in contact with the main plate 21 and a region D in the portion in contact with the shroud 22 from the front edge 23a to the rear edge 23b 4 intersecting when viewed from the axial direction of the rotating shaft 4a.

  Here, in the blade 23, as shown in FIG. 8, the thickness L1max of the thickest portion 23c is 15% to 25% of the chord length L4 from the front edge portion 23a to the rear edge portion 23b at the boundary surface with the main plate 21. Is set in the range. Further, in the blade 23, the distance L5 from the front edge portion 23a to the thickest portion 23c is set in the range of 15% to 30% of the chord length L4.

  In the present embodiment, the blade 23 formed integrally with the main plate 21 is inclined from the positive pressure surface 23d to the negative pressure surface 23e. In the blade 23, the thickness L1max of the thickest portion 23c is set in the range of 15% to 25% of the chord length L4 from the front edge portion 23a to the rear edge portion 23b on the boundary surface with the main plate 21.

  With such a configuration, the blower 3 including the impeller 5 and the indoor unit 1 of the air conditioner including the blower 3 can satisfy the expected performance. The expected performance is the amount of air blown by the impeller 5 when a predetermined power is supplied to the motor 4, the upper limit value of noise and vibration of the impeller 5 when the motor 4 is rotated at a predetermined rotation speed, and This relates to the reference value of the external appearance of the impeller 5. Specific description will be given with reference to Table 1.

  Table 1 shows the ratio of the thickness L1max of the thickest part and the chord length L4 from the front edge part to the rear edge part regarding the performance of the blade. Regarding performance, the best is indicated by ◎, the good is indicated by ○, the acceptable is indicated by △, and the impossible is indicated by ×.

  As shown in Table 1, the blade 23 of the present embodiment has a thickness L1max of the thickest portion 23c set in the range of 15% to 25% of the chord length L4. The recess 23f does not penetrate the positive pressure surface 23d or the negative pressure surface 23e. As a result, the blade 23 can satisfy the designed outer shape without exposing the recess 23f to the outside, and can achieve the expected performance.

  The blade 23 is provided with a recess 23f corresponding to so-called meat removal (meat stealing), so that the difference between the relatively thin portion and the thick portion is reduced. Sinking can be suppressed without setting a long time. In particular, the blade 23 has a sufficient thickness in consideration of being molded integrally with the main plate 21. However, by providing the recess 23f that can be sufficiently thinned, a relatively thin portion and a thick portion. And the difference can be made small. Accordingly, the blade 23 can satisfy the dimensional tolerance of the outer shape without increasing the tact required for manufacturing, that is, without setting the pressure holding time during injection molding to a long time. As a result, the blade 23 can satisfy the expected performance while ensuring productivity.

  In particular, the impeller 5 having the blades 23 is a so-called turbo fan, and is provided in the blower 3 having a relatively large air volume and a high wind pressure. Therefore, it is very important to use the blade 23 in which sink marks are suppressed.

  Furthermore, the blade 23 can be reduced in volume by providing the recessed part 23f. Thereby, the quantity of the synthetic resin material required for shaping | molding of the impeller 5 can be reduced, and the air blower 3 and air conditioner provided with the impeller 5 can be reduced in weight. As a result, the blower 3 provided with the impeller 5 and the indoor unit 1 of the air conditioner provided with the blower 3 increase the productivity by reducing the cost and provide the rigidity necessary for the installation space such as the ceiling by reducing the weight. Can be relaxed.

  As shown in Table 1, when a blade having a thickness L1max of less than 15% of the chord length L4 is used as shown in Table 1, the front edge on the shroud side protrudes from the front edge on the main plate side by design. End up. For this reason, a recessed part cannot fully be formed to the front-end | tip on a shroud side. That is, it cannot provide sufficient meat removal (meat stealing). As a result, when a blade with a relative proportion of 1 is used, sink marks are likely to occur during injection molding, and it is difficult to satisfy the desired performance. In order to suppress sink marks at the time of injection molding, it is necessary to set a longer pressure holding time at the time of injection molding, and the productivity is significantly reduced.

  As shown in Table 1, as shown in Table 1, when a blade having a thickness L1max exceeding 25% of the chord length L4 is used, the space between adjacent blades is narrowed. Since the ventilation path is formed between the adjacent blades, the air flow rate is reduced. As a result, when the blade of the proportional 2 is used, the blowing efficiency is lowered. Note that, in the blade of the proportional 2, in order to maintain the air flow rate, it is necessary to increase the rotation speed, and the power consumption increases and the noise and vibration increase.

  In the present embodiment, in the blade 23, the distance L5 from the front edge portion 23a to the thickest portion 23c is set in the range of 15% to 30% of the chord length L4 from the front edge portion 23a to the rear edge portion 23b. Yes.

  With such a configuration, the blower 3 including the impeller 5 and the indoor unit 1 of the air conditioner including the blower 3 can satisfy the expected performance. Specifically, this will be described with reference to Table 2 and FIGS. 10A to 10C.

  Table 2 shows the ratio of the distance L5 from the front edge portion to the thickest portion and the chord length L4 from the front edge portion to the rear edge portion regarding the performance of the blade. Regarding performance, the best is indicated by ◎, the good is indicated by ○, the acceptable is indicated by △, and the impossible is indicated by ×.

  In this embodiment, as shown in Table 2 and FIG. 10A, when a blade 23 having a distance L5 of 15% to 30% of the chord length L4 is used, the air flowing in from the front edge portion 23a is quickly returned to the rear edge portion 23b. Can be blown out. That is, when the blade 23 of this embodiment is used, energy loss can be sufficiently suppressed in the air flow R1 along the positive pressure surface 23d and the air flow R2 along the negative pressure surface 23e. Therefore, the air flowing in from the front edge portion 23a can maintain the blowing efficiency and suppress noise. As a result, when the blade 23 of the present embodiment is used, the blower 3 and the indoor unit 1 of the air conditioner including the blower 3 can satisfy the expected performance.

  In contrast 3, as shown in Table 2 and FIG. 10B, when a blade 123 formed integrally with the main plate 121 and having a distance L5 of 14% or less of the chord length L4 is used, the air flowing in from the leading edge 123a The rate of collision with the leading edge 123a increases. That is, after a large loss of energy at the leading edge 123a, an air flow R11 along the positive pressure surface 123d and an air flow R12 along the negative pressure surface 123e are generated. Therefore, the air flowing in from the front edge portion 123a is greatly reduced and blown out from the rear edge portion 123b. As a result, the impeller 105 using the proportionally proportional three blades 123 has a reduced blowing efficiency.

  In contrast 4, as shown in Table 2 and FIG. 10C, when a blade 223 that is integrally formed with the main plate 221 and has a distance L5 of 31% or more of the chord length L4 is used, the air flowing from the front edge 223a It is largely divided before reaching the edge 223b. In particular, the air flow R21 along the positive pressure surface 223d and the air flow R22 along the negative pressure surface 223e are largely separated after passing through the thickest portion. Therefore, a large wake vortex is generated in the trailing edge 223b due to the air flowing in from the leading edge 223a. As a result, the impeller 205 using the blade 223 of the proportional 4 increases noise due to the wake vortex. .

  In the present embodiment, the blade 23 is a region C from the front edge 23a to the rear edge 23b in the portion in contact with the main plate 21, and a region from the front edge 23a to the rear edge 23b in the portion in contact with the shroud 22. D intersects when viewed from the axial direction of the rotating shaft 4a.

  Thus, even if the blade 23 is twisted relatively large so that the region C and the region D intersect, the thickness L1max of the thickest portion 23c is set in the range of 15% to 25% of the chord length L4. Yes. For this reason, when manufacturing the blade 23, the concave portion 23f does not penetrate the positive pressure surface 23d and the negative pressure surface 23e. As a result, the blade 23 can satisfy the designed outer shape without exposing the recess 23f to the outside, and can achieve the expected performance.

  In the present embodiment, the shroud 22 and the plurality of blades 23 are joined.

  Therefore, the cost and man-hour required for manufacturing the impeller 5 can be reduced. That is, the impeller 5 can be manufactured only by joining two components as a secondary process. The two parts are a shroud 22 and a plurality of blades 23 formed integrally with the main plate 21. As a result, the blower 3 provided with the impeller 5 and the indoor unit 1 of the air conditioner provided with the blower 3 can be manufactured at low cost while improving the productivity.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

DESCRIPTION OF SYMBOLS 1 ... Indoor unit, 2 ... Blower, 3 ... Heat exchanger, 4 ... Motor, 4a ... Rotating shaft, 5 ... Impeller, 21 ... Main plate, 21a ... Supporting part, 21b ... Boss part, 21c ... Through-hole, 22 ... Shroud, 23 ... Blade, 23a ... Front edge, 23b ... Rear edge, 23c ... Thickest part, 23d ... Pressure surface, 23e ... Suction surface, 23f ... Recess, A, B, C, D ... region, L1 ... The thickness of the blade 23, L1max ... the thickness of the thickest part 23c of the blade 23, L2 ... the depth of the recess 23f of the blade 23, L3 ... the height (full length) of the blade 23, L4 ... the rear from the front edge 23a of the blade 23 The chord length to the edge 23b, L5 ... Distance from the front edge 23a of the blade 23 to the thickest part 23c.

Claims (5)

A main plate provided with a boss portion attached to the rotating shaft of the motor, and a plurality of through holes surrounding the boss portion;
A shroud disposed opposite to the main plate;
A blade having a plurality of blades formed integrally with the main plate by a synthetic resin between the main plate and the shroud and including a recess recessed from the main plate to the shroud while communicating with the through hole inside Equipped with a car,
The blade has a shape twisted in the axial direction of the rotating shaft from the main plate side to the shroud side,
Of the region from the leading edge to the trailing edge, the region from the leading edge to at least the thickest portion having the maximum thickness is inclined from the pressure surface to the suction surface as it goes from the main plate side to the shroud side. And
And the air blower by which the thickness of the said thickest part was set to the range of 15% to 25% of the chord length from the said front edge part in the boundary surface with the said main board to the said rear edge part.   The blower according to claim 1, wherein a distance from the leading edge portion to the thickest portion is set in a range of 15% to 30% of the chord length.   A region of the blade in contact with the main plate from the front edge to the rear edge, and a region of the blade in contact with the shroud from the front edge to the rear edge of the rotating shaft The blower according to claim 1, which intersects when viewed from the axial direction.   The blower according to claim 1, wherein the shroud and the plurality of blades are joined. A box-shaped body,
A heat exchanger housed in the body;
The indoor unit of the air conditioner which comprised the air blower as described in any one of Claim 1 thru | or 4 accommodated in the said main body, and ventilates the said heat exchanger.

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