JP5574841B2 - Turbofan and air conditioner using the same - Google Patents

Description

  The present invention relates to a turbo fan suitable for application to an air conditioner and an air conditioner using the same.

  Conventionally, a turbo fan that does not require a fan case has been used in a ceiling-embedded air conditioner, a floor-standing air conditioner, or the like. In general, a turbofan is provided with a main plate provided with a hub for fixing a rotating shaft at the center, a shroud that forms a fluid flow path disposed opposite to the main plate, and the shroud and the main plate. A plurality of blades provided, and a fluid such as air is sucked from the axial direction into a fluid flow path formed by a shroud through a bell mouth provided on the suction side, and the plurality of blades are It is configured to blow in the radial direction.

  In such a ceiling-embedded air conditioner using a turbo fan, a heat exchanger is disposed on the outer peripheral side of the turbo fan so as to surround the turbo fan, and the air blown from the turbo fan is heated or cooled by the heat exchanger. After that, it blows out into the room. However, in a turbo fan, generally, the flow rate of the blown air blown from the shroud side of the blade is slow, and the wind speed distribution tends to be non-uniform, and the passing wind speed is slow in the lower part of the heat exchanger, causing pressure loss. As a result, the blast power increases, the heat exchanger performance is lower than the unit performance when the unit is mounted, and the aerodynamic noise when passing through the heat exchanger increases.

  Further, in the turbofan, as the blowing width (width in the height direction of the blade) increases, the flow tends to separate on the inner surface of the shroud, and aerodynamic noise tends to increase. Further, after blowing out from the turbo fan, the air flow that circulates along the back surface of the bell mouth and is recirculated from the gap between the bell mouth and the shroud to the shroud inner surface side of the fluid flow path is generated on the shroud inner surface. On the other hand, since it does not serve the original role of supplying blown air to the heat exchanger, it causes unnecessary power consumption and generation of abnormal noise (NZ sound).

  Therefore, in order to equalize the wind speed distribution in the blade height direction at the fan outlet and reduce operating noise, an air flow is formed on the back surface of the shroud from the center of the shroud to the outer periphery along the back surface of the shroud during fan operation. There has been provided a turbofan having a structure provided with a protrusion or a recess (for example, a rib-shaped protrusion) and an air conditioner using the turbofan (see Patent Document 1). In addition, a partition plate is provided between the main plate and the shroud, and the turbo fan is configured in two upper and lower stages to provide a uniform wind speed distribution and reduce noise (see, for example, Patent Document 2).

Japanese Patent No. 4017003 JP 2007-162467 A

  In Patent Document 1, the rib-like protrusions or recesses provided on the back surface of the shroud cause a flow along the back surface of the shroud to induce blowing air and increase the recirculation flow. Is suppressed, the operation noise is reduced, and the wind speed distribution in the blade height direction at the fan outlet is made uniform. However, it is considered that it is difficult to sufficiently control and suppress the recirculation flow and the separation on the inner surface of the shroud only by the protrusions or the recesses. In particular, it has never been desirable to increase the recirculation flow because it leads to unnecessary power consumption and generation of abnormal noise.

  In addition, the one disclosed in Patent Document 2 has a two-stage upper and lower configuration so that the wind speed distribution has two peaks, and the wind speed distribution is made uniform. Since a partition plate is provided between the two parts, it is difficult to form a turbofan with two parts, a shroud, a main plate, and a blade. This increases the number of parts and the number of assembly steps, resulting in an increase in weight. In addition, the manufacturing cost is inevitably high.

  The present invention has been made in view of such circumstances, and is a turbofan capable of suppressing noise separation and uniform wind speed distribution by suppressing separation on the inner surface of the shroud while reducing recirculation flow. And it aims at providing the air conditioner using the same.

In order to solve the above problems, the turbo fan of the present invention and the air conditioner using the same employ the following means.
That is, a turbofan according to the present invention includes a main plate provided with a hub for fixing a rotation shaft at the center, a shroud that forms a fluid flow path disposed opposite to the main plate, and the shroud and the main plate. In the turbofan including a plurality of blades disposed between the slits, a shroud surface between the plurality of blades of the shroud is provided with a slit-like through portion from the center side toward the outer peripheral side. , Chi lifting the inclination angle with respect to the shroud surface toward the back side from the inner surface side of the shroud to the penetrating portion, the louvers blown in the radial direction of the back side is provided to attract the air flow from the inner surface of the shroud It is characterized by.

According to the present invention, a slit-shaped through portion extending from the center side to the outer peripheral side is provided on the shroud surface between the plurality of blades of the shroud, and the through portion is formed with respect to the shroud surface from the inner surface side to the back surface side of the shroud. Chi lifting angle of inclination Te, because it attracts the airflow from the inner surface of the shroud louvers blown in the radial direction of the back side is provided, louvers are provided in the through portion of the shroud is an axial flow fan manner By taking a role and suctioning the flow along the inner surface of the shroud to increase the air flow, separation of the flow on the inner surface of the shroud can be suppressed. In addition, as a result of the axial flow fan action of the louver, a part of the air flow is blown out in the radial direction through centrifugal force, and as a result, the air flow along the inner surface of the shroud increases and the blades are shunted from the shroud side. The amount of blowing air can be increased, and the wind speed distribution in the blowing width direction can be made uniform. As a result, in the turbo fan, noise can be reduced by suppressing separation on the inner surface of the shroud and the wind speed distribution of the blown air can be made uniform, and at the same time, the recirculation flow can be suppressed by the blown air in the radial direction from the louver. Therefore, it is possible to reduce the recirculation flow and to suppress unnecessary power consumption and generation of abnormal noise (NZ sound).

  Furthermore, the turbofan of the present invention is characterized in that in the above turbofan, the louver is provided integrally with the shroud in the slit-like through portion.

  According to the present invention, since the louver is provided integrally with the shroud in the slit-like through portion, the slit-like through portion and the louver can be integrally formed on the shroud surface simultaneously when the shroud is formed. As a result, an increase in the number of parts and assembly man-hours can be suppressed, and an increase in weight and an increase in cost due to noise reduction and wind speed distribution improvement measures can be eliminated.

  Furthermore, the turbo fan of the present invention is the turbo fan according to any one of the above-mentioned turbo fans, wherein the louver has an inclination angle such that the upstream end in the rotational direction of the louver enters the inner surface side of the shroud, and the downstream end in the rotational direction is the shroud. It is set as the angle of the magnitude | size projected on the back surface side.

  According to the present invention, the inclination angle of the louver is such that the upstream end in the rotational direction of the louver enters the inner surface side of the shroud and the downstream end in the rotational direction protrudes to the back side of the shroud. Therefore, the flow along the shroud inner surface is surely attracted to the through portion by the rotation direction upstream end entering the shroud inner surface side of the louver, and the flow is radially directed by the rotation direction downstream end protruding to the shroud back surface side. Can be blown out. Therefore, the air flow along the inner surface of the shroud can be increased, the separation of the flow on the inner surface side of the shroud can be surely suppressed, the amount of blowing air from the shroud side can be increased, and the wind speed distribution in the blowing width direction can be made uniform. be able to.

  Furthermore, the turbo fan of the present invention is characterized in that, in any one of the above-described turbo fans, the inclination angle of the louver is largest on the outer peripheral end side and gradually decreases toward the center side.

  According to the present invention, since the inclination angle of the louver is the largest on the outer peripheral end side and gradually decreased toward the center side, by increasing the inclination angle on the outer peripheral end side where the circumferential speed becomes faster, The flow along the inner surface of the shroud can be efficiently attracted to the penetrating portion, and blown out in the radial direction by centrifugal action from the rear surface side of the shroud. Therefore, it is possible to maximize the effects of suppressing the peeling by the louver and uniforming the wind speed distribution, and facilitate the integral molding with the shroud.

  Furthermore, the turbo fan of the present invention is characterized in that, in any of the above turbo fans, the mounting angle of the louver is made larger than the mounting angle of the blade.

  According to the present invention, since the mounting angle of the louver is made larger than the mounting angle of the blade, the air flow along the suction surface side of the blade is swept up by the louver having a large mounting angle, so that the through portion Can be effectively attracted to. Thereby, the flow along the inner surface side of the shroud can be increased, separation of the flow on the inner surface of the shroud can be suppressed, and the wind speed distribution in the blowing width direction can be made uniform. Here, the mounting angle means an angle formed by an inclination angle of the louver and the blade with respect to the radial direction and a tangent to the outer periphery of the shroud, and the louver stands more in the radial direction than the blade.

  Furthermore, the turbo fan of the present invention is characterized in that, in any of the above-described turbo fans, the louver has a wing shape in cross section.

  According to the present invention, since the cross section of the louver has an airfoil shape, wind noise during rotation by the louver itself can be reduced. As a result, further noise reduction can be achieved.

  Furthermore, the turbo fan of the present invention is characterized in that, in any of the above-described turbo fans, the distance between the louver and the blade is uneven between the blades.

  According to the present invention, since the distance between the louver and the blade is uneven among the blades, the flow pattern can be changed between the blades. Accordingly, the NZ sound represented by N / 60 × Z (N: rotation speed, Z: frequency sound of the number of blades) can be reduced, as in the case where the blades are set at unequal pitches.

  Furthermore, the turbo fan of the present invention is characterized in that, in any one of the above-described turbo fans, a sub blade is erected on the back surface of the shroud on the downstream side in the rotation direction of the slit-shaped through portion.

  According to the present invention, since the sub blade is erected on the back surface of the shroud on the downstream side in the rotation direction of the slit-shaped through portion, the radial velocity is further increased by the sub blade against the flow attracted to the through portion by the louver. Ingredients can be given. As a result, the recirculation flow can be suppressed, the flow rate can be further reduced to prevent unnecessary power consumption and noise generation, and the wind speed distribution in the blowing width direction can be made more uniform.

  Furthermore, the turbofan of the present invention is characterized in that in the above turbofan, the sub-blade is integrally raised from the back surface of the shroud.

  According to the present invention, since the sub blade is integrally raised from the rear surface of the shroud, the sub blade is raised from the rear surface of the shroud to the downstream side of the slit-like through portion and the louver when the shroud is formed and integrally molded. be able to. As a result, an increase in the number of parts and assembly man-hours can be suppressed, and cost increase factors in noise reduction and wind speed distribution improvement measures can be eliminated.

  Furthermore, an air conditioner according to the present invention is characterized in that any one of the above-described turbofans is mounted.

  According to the present invention, since any one of the above-described turbofans is mounted, it is possible to reduce fan noise in the air conditioner and to make the wind speed distribution uniform with respect to the heat exchanger, The heat exchange performance in the heat exchanger can be enhanced. Therefore, further reduction in noise and performance of the air conditioner can be achieved.

  Furthermore, in the air conditioner of the present invention, in the above air conditioner, a part of the bell mouth in which an air suction port is formed on the shroud side of the turbofan has a predetermined gap with the inner surface side of the shroud. It is characterized by being overlapped.

  According to the present invention, since a part of the bell mouth in which the air suction port is formed is overlapped with the inner surface side of the shroud through the predetermined gap on the shroud side of the turbofan, A part of the wind is recirculated along the back surface of the bell mouth to the inner surface side of the shroud through the gap between the overlapping portions of the bell mouth and the shroud, and this recirculation flow is applied to the louver provided on the back surface of the shroud and / or It can suppress by the blowing wind which blows off in a radial direction via a subblade. Therefore, it is possible to control the flow rate of the recirculation flow to an appropriate amount and contribute to suppression of separation on the inner surface of the shroud, and at the same time, it is possible to suppress unnecessary power consumption and generation of abnormal noise.

  Furthermore, the air conditioner of the present invention is characterized in that, in any of the air conditioners described above, a heat exchanger is disposed on the outer peripheral side of the turbofan so as to surround the turbofan.

  According to the present invention, since the heat exchanger is disposed on the outer peripheral side of the turbo fan so as to surround the turbo fan, the wind speed distribution in the portion of the heat exchanger facing the shroud side of the turbo fan in particular is obtained. It is possible to improve the heat exchange performance by making uniform use of the entire area of the heat exchanger. Therefore, it is possible to suppress the performance deterioration when the heat exchanger is mounted and to improve the performance of the air conditioner.

According to the turbofan of the present invention, are we provided in the through portion of the shroud, louvers blowing from the inner side of the shroud in the radial direction of attract airflow back surface side, responsible for axial fan role, the shroud by increasing the air flow by sucking the flow along the inner surface, Ki out to suppress flow separation at the shroud inner surface, also part of the air through the through portion by axial fan action of louvers As a result of the flow being blown out in the radial direction by centrifugal force, combined with the increase in the air flow along the inner surface of the shroud, the amount of blown air from the shroud side of the blade can be increased, and the air velocity distribution in the blowing width direction can be made uniform Therefore, it is possible to reduce the noise in the turbo fan and make the wind speed distribution uniform, and at the same time, by suppressing the recirculation flow with the blowing air from the louver in the radial direction. Reducing the recycle stream, it can be suppressed the occurrence of wasteful power consumption and noise (NZ sound).

  According to the air conditioner of the present invention, it is possible to reduce fan noise in the air conditioner and to improve the heat exchange performance in the heat exchanger by making the wind speed distribution uniform with respect to the heat exchanger. Therefore, further reduction in noise and performance of the air conditioner can be achieved.

1 is a perspective view of an air conditioner to which a turbofan according to a first embodiment of the present invention is applied. It is a longitudinal cross-sectional view of the indoor unit of the air conditioner shown in FIG. It is the top view which looked at the turbo fan applied to the indoor unit shown in FIG. 2 from the shroud side. It is an AA cross-section equivalent figure (A) in FIG. 3, a BB cross-section equivalent figure (B), and a CC cross-section equivalent figure (C). It is a wind speed distribution map of the blowing air of the turbo fan shown in FIG. It is an AA cross section equivalent figure in Drawing 3 of a turbofan concerning a 2nd embodiment of the present invention. It is the top view seen from the shroud side of the turbofan which concerns on 3rd Embodiment of this invention. It is the top view seen from the shroud side of the turbofan which concerns on 4th Embodiment of this invention. FIG. 9 is a cross-sectional view taken along the line DD in FIG. 8.

Embodiments according to the present invention will be described below with reference to the drawings.
[First Embodiment]
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. 1 to 5.
FIG. 1 is a perspective view of a ceiling-embedded air conditioner to which a turbofan according to the first embodiment of the present invention is applied, and FIG. 2 is a longitudinal sectional view thereof. Here, an example of a ceiling-embedded air conditioner 1 in which one indoor unit 3 is connected to the outdoor unit 2 is shown.

  The ceiling-embedded air conditioner 1 is used in which an indoor unit 3 is suspended from an indoor ceiling and connected to an outdoor unit 2 installed outdoors via a refrigerant pipe 4 and an electrical wiring 5. It is. The outdoor unit 2 is provided with devices such as a refrigerant compressor 6, an outdoor heat exchanger 7, an outdoor fan 8, a control box 9, and a four-way switching valve (not shown). The outdoor unit 2 constitutes a refrigeration cycle together with an indoor heat exchanger 17 (described later) provided on the indoor unit 3 side, and has a function of adjusting the refrigerant supplied to the indoor unit 3.

  The indoor unit 3 includes a cabinet 10 whose lower portion is opened, and a substantially rectangular ceiling panel 11 attached to a lower portion of the cabinet 10. A bell mouth 13 that forms an air inlet 12 and a drain pan 14 are installed in a lower part of the cabinet 10, and an air passage 15 is formed by a part of the drain pan 14. In addition, a turbo fan 17 that is rotationally driven by a fan motor 16 is installed at a central portion of the top plate of the cabinet 10, and indoor heat that is bent into a quadrangular shape so as to surround the outer periphery of the turbo fan 17. The exchanger 18 is fixedly installed on the top plate side via a bracket (not shown).

  As a result, the room air is introduced into the cabinet 10 via the bell mouth 13 forming the air suction port 12 to the turbo fan 17, and the air boosted by the turbo fan 17 and blown in the radial direction is supplied to the outer periphery of the cabinet 10. An air flow passage 19 is formed through the indoor heat exchanger 18 disposed so as to surround the air flow path 15 to the air passage 15 formed by the inner surface of the cabinet 10 and the outer peripheral surface of the drain pan 14.

  Further, the rectangular ceiling panel 11 is provided with a rectangular air outlet 20 for blowing conditioned air along the four sides thereof so as to communicate with the air passage 15 and sucks room air into the central portion. An opening 21 is provided. A suction grill 23 provided with an air filter 22 and the like is provided in the opening 21 so as to be movable up and down via a wire 24 and the like, as shown in FIG. Each air outlet 20 is provided with an air direction adjusting louver 25 for adjusting the direction of the conditioned air blown from the outlet 20 so as to be individually swingable.

  The turbo fan 17 forms a main plate 27 provided with a hub 26 for fixing the rotating shaft 16A of the fan motor 16 at the center, and a fluid flow path 28 disposed opposite to the main plate 27. The shroud 29 and a plurality of blades 30 disposed between the shroud 29 and the main plate 27. The turbofan 17 is arranged so that the shroud 29 side is opposed to the air inlet 12 of the bell mouth 13, and a part of the bell mouth 13 is overlapped with the inner periphery of the shroud 29, during which the air blown from the turbofan 17 A recirculation path 31 is formed to circulate a part along the back surface of the bell mouth 13 to the inner surface 29 </ b> A side of the shroud 29 from the gap between the overlapping portions of the bell mouth 13 and the shroud 29.

  In the present embodiment, in the turbo fan 17 having such a configuration, as shown in FIGS. 3 and 4, a plurality of slit-like shapes extending from the center side to the outer peripheral side are formed on the shroud surface between the plurality of blades 30 of the shroud 29. A through portion 32 is provided, and each of the through portions 32 is provided with a louver 33 having an inclination angle θ with respect to the shroud surface from the inner surface side to the rear surface side of the shroud 29.

  The louver 33 is formed integrally with the shroud 29 so as to be cut and raised from the shroud 29. The inclination angle θ of the louver 33 is such that the upstream end 33A in the rotational direction of the louver 33 is at the shroud 29 as shown in FIG. The angle is such that the downstream end 33B in the rotation direction protrudes toward the back surface 29B side of the shroud 29. In addition, the inclination angle θ is maximized on the outer peripheral end side of the louver 33, is gradually decreased from the outer peripheral side toward the central side, and is flush with the shroud surface at the central end.

Further, the louver 33 has a louver mounting angle α defined by an angle formed by the inclination angle of the louver 33 with respect to the radial direction and a tangent to the outer periphery of the shroud 29, and α> β with respect to a similar mounting angle β of the blade 30. As is apparent from FIG. 3, the louver 33 is provided in a state of standing in the radial direction rather than the blade 30.
The turbofan 17 is made of a resin material, and is manufactured by integrally molding the main plate 27 and the blade 30 and ultrasonically welding a shroud 29 molded separately from the main plate 27 and the blade 30. is there.

With the configuration described above, according to the present embodiment, the following operational effects can be obtained.
When the turbo fan 17 is driven by the fan motor 16 and rotated in the N direction (see FIG. 3), the indoor air passes through the air filter 22 from the suction grille 23 as indicated by the white arrow shown in FIG. 3 is further sucked into the fluid flow path 28 of the turbofan 17 from the air suction port 12 of the bell mouth 13. The air flow is pressurized by the blade 30, blown in the radial direction from the outer peripheral end (rear edge) along the height direction of the blade 30, and then heated or cooled by the heat exchanger 18. The air whose temperature has been adjusted by the heat exchanger 18 is blown into the room from the air outlet 20 through the air passage 15 and is used for indoor heating or cooling.

  In the indoor unit 3, the heat exchanger 18 disposed so as to surround the outer periphery of the turbofan 17 may have a uniform air velocity distribution in the height direction to circulate the air flow. The entire area is effectively utilized to improve the heat exchange performance, and the performance of the air conditioner 1 is improved. For this purpose, the wind speed distribution in the direction of the blown-out wind from the turbo fan 17 (the width in the height direction of the blade 30) is made uniform, and in particular, the amount of the blown-out wind blown from the shroud 29 side of the turbo fan 17 is increased. The problem is how to increase the air flow toward the lower part of the heat exchanger 18.

  However, in the turbofan 17 according to the present embodiment, slit-like through portions 32 are provided on the shroud surface between the plurality of blades 30 of the shroud 29 from the center side toward the outer peripheral side. Further, a louver 33 having an inclination angle θ with respect to the shroud surface from the inner surface 29A side to the rear surface 29B side of the shroud 29 is provided. The louver 33 plays a role as an axial flow fan, and as shown in FIG. 5A, the air flow S1 along the inner surface 29A of the shroud 29 is sucked to increase the air flow, so that the shroud inner surface is increased. Flow separation at 29A can be suppressed.

  Further, due to the axial fan action of the louver 33, as shown in FIG. 5A, a part of the air flow S <b> 2 is blown out in the radial direction through the penetrating portion 32, and as a result, the inner surface of the shroud 29. Combined with the increase in the air flow S1 along 29A, the amount of air blown from the shroud 29 side of the blade 30 is increased, and the wind speed distribution in the blowout width direction is made uniform with respect to the conventional example shown in FIG. can do.

  As a result, in the turbofan 17, it is possible to reduce noise and to make the wind speed distribution of the blown air uniform by suppressing separation on the inner surface 29A of the shroud. Moreover, by this, the amount of blowing air to the lower part of the heat exchanger 18 can be increased, the heat exchange performance can be improved, and the performance of the air conditioner 1 can be improved and the noise can be reduced. At the same time, the recirculation flow S3 to the recirculation path 31 between the bell mouth 13 and the shroud 29 is suppressed by the radial blowing air (air flow S2) blown from the louver 33, and the flow rate is reduced. Since it can be controlled to an appropriate amount, wasteful power consumption and generation of abnormal noise such as NZ noise can be suppressed while contributing to suppression of peeling on the inner surface 29A of the shroud 29.

  Further, since the louver 33 is provided by being integrally formed with the shroud 29 in the slit-like through portion 32, the slit-like through portion 32 and the louver 33 are simultaneously integrated with the shroud surface when the shroud 29 is formed. Can be molded. Therefore, an increase in the number of parts and assembly man-hours can be suppressed, and an increase in weight and an increase in cost due to noise reduction and wind speed distribution improvement measures can be eliminated.

  Further, the louver 33 has an inclination angle θ such that the upstream end 33A in the rotational direction of the louver 33 enters the inner surface 29A side of the shroud 29 and the downstream end 33B in the rotational direction protrudes toward the back surface 29B of the shroud 29. The angle is θ. For this reason, the air flow S1 along the shroud inner surface 29A is surely attracted to the penetrating portion 32 by the upstream end 33A in the rotational direction entering the shroud inner surface 29A side of the louver 33 (arrow S4 in FIG. 4A), The flow can be blown out like the air flow S2 in the radial direction by the centrifugal action of the rotation direction downstream end 33B protruding toward the shroud back surface 29B. Therefore, the air flow S1 along the shroud inner surface 29A can be increased, and the separation of the flow on the shroud inner surface 29A side can be reliably suppressed, the amount of blown air from the shroud 29 side can be increased, and the wind speed distribution in the blow width direction Can be made uniform.

  Further, the inclination angle θ of the louver 33 is the largest at the outer peripheral end side and is gradually decreased toward the center side. Therefore, by increasing the inclination angle θ at the outer peripheral end side at which the circumferential speed increases, the shroud is increased. The air flow S1 along the inner surface 29A is efficiently attracted to the penetrating portion 32 (arrow S4 in FIG. 4 (A)), and as shown in FIG. 5 (A), the shroud rear surface 29B is centrifugally actuated in the radial direction. It can blow out like the air flow S2. Accordingly, it is possible to maximize the effects of suppressing the separation by the louver 33 and uniforming the wind speed distribution, and facilitate the integral molding with the shroud 29.

  Furthermore, in this embodiment, the mounting angle α of the louver 33 is larger than the mounting angle β of the blade 30 and α> β, and the mounting angle α is increased for the air flow along the suction surface side of the blade 30. It is possible to effectively attract the penetrating portion 32 (arrow S4 in FIG. 4A) so as to scoop up by the louver 33. For this reason, the air flow S1 along the inner surface 29A side of the shroud 29 can be increased, the separation of the flow on the shroud inner surface 29A can be suppressed, and the wind speed distribution in the blowing width direction can be made uniform.

[Second Embodiment]
Next, a second embodiment of the present invention will be described with reference to FIG.
This embodiment is different from the first embodiment described above in that the louver 33 has an airfoil cross-sectional shape. Since other points are the same as those in the first embodiment, description thereof will be omitted.
In this embodiment, the cross-sectional shape of the louver 33 provided in the penetration part 32 of the shroud 29 is an airfoil shape 33C as shown in FIG.
Thus, by setting the cross-sectional shape of the louver 33 to the airfoil shape 33C, it is possible to reduce wind noise during rotation by the louver 33 itself. For this reason, the noise of the turbo fan 17 can be further reduced.

[Third Embodiment]
Next, a third embodiment of the present invention will be described with reference to FIG.
This embodiment is different from the first and second embodiments described above in that the distance γ between the louver 33 provided between the plurality of blades 30 and each blade 30 is uneven. . Since other points are the same as those in the first and second embodiments, description thereof will be omitted.
In the present embodiment, as shown in FIG. 7, the distance γ between each louver 33 and each blade 30 provided in the penetrating portion 32 of the shroud 29 between the plurality of blades 30 is γ1. ≠ γ2 ≠... ΓN, and the blades 30 are not uniform.

  Thus, by making the distances γ between the louvers 33 and the blades 30 uneven between the blades 30, the flow pattern can be changed for each blade 30. For this reason, the NZ sound represented by N / 60 × Z (N: rotation speed, Z: frequency sound of the number of blades) can be reduced as in the case where the blades 30 are arranged at unequal pitches. The noise can be further reduced.

[Fourth Embodiment]
Next, a fourth embodiment of the present invention will be described with reference to FIGS.
This embodiment is different from the first to third embodiments described above in that a sub blade 34 is provided on the shroud back surface 29B on the downstream side in the rotation direction of the penetrating portion 32. Since other points are the same as those in the first to third embodiments, the description thereof will be omitted.
In this embodiment, as shown in FIGS. 8 and 9, between the plurality of blades 30 of the shroud 29, the shroud back surface 29B is erected in the axial direction on the shroud back surface 29B on the downstream side in the rotational direction. The sub-blade 34 is provided.

  As described above, by adopting a configuration in which the sub-blade 34 is erected on the shroud back surface 29B on the downstream side in the rotation direction of the slit-shaped through part 32, the air flow S4 attracted to the through part 32 by the louver 33 Further, the sub-blade 34 can provide a velocity component in the radial direction. As a result, the recirculation flow S3 can be suppressed and the flow rate can be further reduced to suppress wasteful power consumption and generation of abnormal noise, and the wind speed distribution in the blowing width direction can be made more uniform.

  In addition, this invention is not limited to the invention concerning the said embodiment, In the range which does not deviate from the summary, it can change suitably. For example, in the above-described embodiment, an example in which one set of slit-like through portions 32 and louvers 33 is provided between a plurality of blades 30 has been described. However, a plurality of slit-like through portions 32 and louvers 33 are provided between the blades 30. It is good also as a structure provided as a set.

  Further, the air conditioner 1 is not limited to the ceiling-embedded air conditioner 1 shown in FIG. 1, but can be applied to other types of air conditioners such as a floor-mounted air conditioner as well. It is. Furthermore, it goes without saying that the turbo fan 17 can be applied to uses other than the air conditioner.

DESCRIPTION OF SYMBOLS 1 Ceiling embedded type air conditioner 12 Air suction inlet 13 Bell mouth 17 Turbo fan 18 Heat exchanger 26 Hub 27 Main plate 28 Fluid flow path 29 Shroud inner surface 29B Shroud back surface 30 Blade 32 Slit-like penetration part 33 Louver 33A Louver rotation direction upstream end 33B Louver rotation direction downstream end 33C Airfoil shape 34 Sub blade θ Louver inclination angle α Louver attachment angle β Blade attachment angles γ1, γ2 Distance between louver and blade

Claims (12)

A main plate provided with a hub for fixing the rotation shaft at the center, a shroud forming a fluid flow path disposed opposite to the main plate, and a plurality of plates disposed between the shroud and the main plate In a turbofan with a single blade,
The shroud surface between the plurality of blades of the shroud is provided with a slit-like through portion from the center side toward the outer peripheral side, and the through portion is inclined with respect to the shroud surface from the inner surface side to the back surface side of the shroud. Chi lifting angle, turbofan, characterized in that to attract the air flow louvers blown in the radial direction of the back side are provided from the inner surface side of the shroud.   2. The turbo fan according to claim 1, wherein the louver is provided integrally with the shroud in the slit-shaped through portion.   The inclination angle of the louver is such that the upstream end in the rotational direction of the louver enters the inner surface side of the shroud and the downstream end in the rotational direction protrudes to the back side of the shroud. The turbo fan according to claim 1 or 2.   The turbofan according to any one of claims 1 to 3, wherein the inclination angle of the louver is largest at the outer peripheral end side and gradually decreased toward the center side.   The turbofan according to claim 1, wherein an attachment angle of the louver is larger than an attachment angle of the blade.   The turbofan according to any one of claims 1 to 5, wherein the louver has a wing shape in cross section.   The turbo fan according to claim 1, wherein the distance between the louver and the blade is uneven between the blades.   The turbofan according to any one of claims 1 to 7, wherein a sub-blade is erected on the rear surface of the shroud on the downstream side in the rotation direction of the slit-shaped through portion.   The turbo fan according to claim 8, wherein the sub-blade is integrally raised from a back surface of the shroud.   An air conditioner equipped with the turbofan according to any one of claims 1 to 9.   The part of the bell mouth in which the air suction port is formed in the shroud side of the turbofan is overlapped with the inner surface side of the shroud via a predetermined gap. Air conditioner. The air conditioner according to claim 10 or 11, wherein a heat exchanger is disposed on an outer peripheral side of the turbo fan so as to surround the turbo fan.

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