JP3632745B2 - Air conditioner - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an air conditioner using a turbo fan as a blower.
[0002]
[Prior art]
Conventionally, turbofans have been widely used as blowers for air conditioners. Recently, however, there has been a strong demand for higher performance, higher efficiency, and lower noise. For example, Japanese Patent Laid-Open No. 7-4389 Discloses a method for improving the performance by improving the blade shape.
[0003]
The shape of this conventional turbofan is shown in FIG. In this turbofan, as shown in the enlarged view of FIG. 25, the blade 23 has an inflection point 13 in the vicinity of the blade trailing edge 9 in a cross section perpendicular to the motor rotation axis. Up to the point 13, the airfoil is formed in the fan rotation direction 6, and the inflection point 13 to the blade trailing edge 9 have a substantially vertical shape in the fan rotation direction 6. For this reason, the exit angle β2 of the blade is increased, and the discharge pressure can be increased.
[0004]
[Problems to be solved by the invention]
However, in order to reduce the size and increase the efficiency, in the above-described configuration, the air flow separation 27 occurs on the suction surface 11 side of the blade trailing edge 9 particularly in the small flow rate region as shown in FIG. It had the problem of not being right.
[0005]
In view of the above problems, the object of the present invention is to maintain or increase the outlet angle on the pressure surface side necessary for maintaining or increasing the discharge pressure of the turbofan, and to reduce the air flow on the suction surface side. An object of the present invention is to provide a high-efficiency, low-noise air conditioner by suppressing the occurrence of separation to improve the performance and efficiency of a turbofan in the sense of reducing motor input.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, the air conditioner according to the present invention is characterized by what is stated in the respective claims, and in particular, the air according to the invention according to claim 1 as an independent claim. The air conditioner is an air conditioner that includes a blower that sucks and discharges air, and a heat exchanger that is disposed on the suction side or discharge side of the blower and that cools or heats the air. A disc-shaped boss provided with a hole for mounting the motor rotation shaft on the center axis, a hub disposed in contact with the outer peripheral edge of the boss, and in the circumferential direction about the motor rotation shaft on the surface of the hub An impeller comprising a plurality of disposed blades and a shroud disposed on the side facing the hub across the blade, and a motor for rotating the impeller by fixing a motor rotation shaft to the boss. Configured turbo In the air conditioner using the above, in each blade cross section perpendicular to the motor rotation axis of the turbofan, the suction surface where the outlet angle on the pressure surface side of the front surface on the rotation direction side of the blade is the blade surface on the back surface It is characterized by having a shape larger than the side exit angle. In addition, the airfoil according to claim 2 and claim 4 dependent on claim 1 means that the blade shape is formed by a curve whose cross-sectional shape is convex toward the rotation direction of the fan.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of a turbofan used in an air conditioner according to the present invention will be described below with reference to FIGS.
[0008]
FIG. 1 is a partially broken plan view of a turbofan of an air conditioner according to a first embodiment of the present invention, and FIG. 2 is a longitudinal sectional view. The turbofan includes a disk-shaped boss 2 provided with a hole for mounting a motor rotation shaft on a central axis, a hub 3 disposed in contact with an outer peripheral edge of the boss 2, and the motor on the surface of the hub 3. An impeller comprising a plurality of blades 4 disposed in the circumferential direction around the rotation axis, and a shroud 5 disposed on the side facing the hub 3 across the blades 4, and a motor on the boss 2 The motor 7 is configured to fix the rotating shaft 8 and rotate the impeller, and is driven to rotate in the rotation direction 6 indicated by an arrow in FIG.
[0009]
FIG. 3 is an enlarged view of the blade trailing edge 9, an intersection of the pressure surface 10 of the blade 4 and the outer periphery 1 of the turbofan (hereinafter referred to as “the trailing edge on the pressure surface 10 side”), and the motor rotation shaft. 8 is an angle formed by the straight line 25a orthogonal to the straight line 24a at the trailing edge of the pressure surface 10 side and the pressure surface 10 at the trailing edge of the pressure surface 10 side (hereinafter referred to as "the pressure surface 10 side"). Β2a, the intersection of the suction surface 11 of the blade 4 and the turbo fan outer periphery 1 (hereinafter referred to as “rear edge of the suction surface 11 side”) and the center of the motor rotating shaft 8 are connected. An angle formed by a straight line 25b perpendicular to the trailing edge of the suction surface 11 side and the suction surface 11 at the trailing edge of the suction surface 11 side (hereinafter, referred to as “exit angle on the suction surface 11 side”). Let β2b. At this time, in a cross section obtained by cutting the blade 4 along a plane perpendicular to the motor rotating shaft 8, the outlet angle β2a on the pressure surface 10 side is larger than the outlet angle β2b on the negative pressure surface 11 side as shown in FIG. Blade 4 shape was adopted.
[0010]
In this embodiment, by making the outlet angle β2b on the negative pressure surface 11 side smaller than the outlet angle β2a on the pressure surface 10 side, air flow separation 27 on the negative pressure surface 11 side is less likely to occur, and the efficiency can be improved. . On the other hand, since the outlet angle β2a on the pressure surface 10 side can be larger than the outlet angle β2b of the negative pressure surface 11, the discharge pressure at the fan outlet can be increased.
[0011]
4 is a longitudinal sectional view of an indoor unit of an air conditioner equipped with the turbo fan 29 shown in FIG. The illustrated indoor unit includes a box-shaped cabinet 28 with one side open, a turbo fan 29 fixed to the opening of the cabinet 28, and a heat exchanger 30 disposed around the outlet of the turbo fan 29. Has been. A bell mouth 31 is disposed at the inlet of the impeller, and a suction grill 33 having a filter 32 is mounted below the bell mouth 31. A panel 34 having an air outlet 35 is disposed on the downstream side of the heat exchanger 30.
[0012]
In the indoor unit configured as described above, air passes from the room through the suction grill 33 and the filter 32 and is sucked into the turbo fan 29 while being rectified by the bell mouth 31. The air discharged from the turbo fan 29 is cooled or heated by the heat exchanger 30 and blown out into the room through the air outlet 35 of the panel 34.
[0013]
FIG. 5 is an enlarged cross-sectional view taken along the line BB of part A of FIG. 4 which is a blower outlet of the turbo fan. As shown in FIG. 5, the outlet angle β2a on the pressure surface 10 side is larger than the outlet angle β2b on the negative pressure surface 11 side.
[0014]
The indoor unit of the air conditioner of the present invention can keep power consumption low because the efficiency of the turbo fan 29 is high, and can keep the fan rotation speed for producing the same air volume low because the discharge pressure is large.
[0015]
Although the present embodiment shows an example in which the turbo fan 29 is applied to an indoor unit of an air conditioner installed on an indoor ceiling, it can also be applied to an outdoor unit. In addition, although the heat exchanger 30 is provided on the discharge side, the heat exchanger 30 may be provided on the suction side.
[0016]
FIG. 6 is a partially cutaway plan view of a turbofan 29 of an air conditioner according to a second embodiment of the present invention, and FIG. 7 is an enlarged view of the blade trailing edge 9. The difference from the first embodiment is that the shape of the pressure surface 10 has an inflection point 13 in the vicinity of the blade trailing edge 9 on the cross section perpendicular to the motor rotating shaft 8, and the inflection point from the blade leading edge. Up to 13, the shape of the pressure surface 10 forms an airfoil toward the fan rotation direction 6, and from the inflection point 13 to the blade trailing edge 9, a concave curve or a vertical curve toward the fan rotation direction 6 It is the point comprised so that it may become. On the other hand, the shape on the negative pressure surface 11 side forms an airfoil toward the fan rotation direction 6 over the entire length of the blade 12. In the second embodiment, the loss due to the air flow separation 27 on the suction surface side can be suppressed in the same manner as in the first embodiment, and the outlet angle β2a on the pressure surface 10 side can be increased to almost vertical. Therefore, a turbo fan having a higher discharge pressure at the fan outlet can be obtained as compared with the first embodiment, the fan rotation speed of the air conditioner can be further reduced, and the blowing sound can be reduced.
[0017]
In the present embodiment, an example in which the shape of the pressure surface 10 forms an airfoil from the blade leading edge to the inflection point 13 toward the fan rotation direction 6 is shown.
[0018]
FIG. 8 is a partially cutaway plan view of a turbofan 29 of an air conditioner according to a third embodiment of the present invention, and FIG. 9 is an enlarged view of the blade trailing edge 9. The difference from the second embodiment is that the blade trailing edge portion 9 is branched into two, a pressure surface side blade trailing edge 15 and a suction surface side blade trailing edge 16. Since the shape of the pressure surface 10 and the suction surface 11 is the same as that of the second embodiment, the blowing performance of the turbo fan 29 is the same as that of the second embodiment, but the flesh pressure at the blade trailing edge 9 is reduced. This has the advantage that the material can be reduced.
[0019]
Comparing the turbo fan 29 of FIG. 8 with the conventional turbo fan 29 shown in FIG. 24, the discharge pressure is about the same, and the efficiency is improved by about 3 to 5% in the use range of the air conditioner. When this turbo fan is mounted on the indoor unit of the air conditioner shown in FIG. 4, the power consumption of the indoor unit can be reduced by about 3 to 5%.
[0020]
FIG. 10 is a partially cutaway plan view of a turbofan 29 of an air conditioner according to a fourth embodiment of the present invention, and FIG. 11 is an enlarged view of the blade trailing edge 9. This embodiment is different from the third embodiment in that a through hole 19 is provided from the pressure surface 10 side toward the intermediate portion 17 in the pressure surface side blade trailing edge 15. In the first to third embodiments, since the distance between the pressure surface 10 and the suction surface 11 is separated at the blade trailing edge 9, for example, in the third embodiment, the pressure surface side blade trailing edge 15 as shown in FIG. Further, due to the pressure difference between the suction surface side blade trailing edge 16 and the intermediate portion 17, a vortex 26 is generated from the tips of the pressure surface side blade trailing edge 15 and the suction surface side blade trailing edge 16, which causes turbulent noise. It is possible. On the other hand, in the fourth embodiment, air flows into the intermediate portion 17 from the pressure surface side blade trailing edge 15 through the through hole 19, whereby the pressure of the intermediate portion 17 can be increased. Therefore, the pressure difference between the pressure surface side blade trailing edge 15 and the suction surface side blade trailing edge 16 and the intermediate portion 17 is reduced, and as shown in FIG. 13, the pressure surface side blade trailing edge 15 and the suction surface side. Generation of large vortices at the blade trailing edge 16 can be suppressed, the discharge pressure and efficiency can be increased, turbulence noise can be reduced, and a highly efficient and low noise air conditioner can be provided.
[0021]
FIG. 14 is a partially broken plan view of a turbofan 29 of an air conditioner according to a fifth embodiment of the present invention, FIG. 15 is a longitudinal sectional view, and FIGS. 8 is an enlarged view of a blade trailing edge portion 9 at an AA cross section, a BB cross section, and a CC cross section perpendicular to FIG. This embodiment is different from the first to fourth embodiments in that the pressure surface side outlet angle β2a of the blade trailing edge portion 9 is formed in a blade shape that differs depending on the height. That is, on the CC cross section shown in FIG. 18, the outlet angle β2a on the pressure surface 10 side is a conventional shape smaller than the outlet angle β2b on the negative pressure surface 11 side, but heads from the hub 3 side to the shroud 5 side. As the cross-sectional shape continuously changes, the outlet angle β2a on the pressure surface side 10 gradually increases. Therefore, in the fifth embodiment, the effect of increasing the discharge pressure increases from the hub 3 side toward the shroud 5 side. As a result, the pressure distribution in the height direction at the fan outlet 21 can be improved, and the shroud 5 side is improved. The air flow separation 27 is suppressed, and the velocity distribution between the hub 3 and the shroud 5 of the blown air is made uniform. That is, efficiency and discharge pressure can be improved, and the maximum speed at the outlet can be kept small, so that fluid noise can be reduced.
[0022]
FIG. 19 is a partially broken plan view of a turbo fan 29 of an air conditioner according to a sixth embodiment of the present invention, FIG. 20 is a longitudinal sectional view, and FIGS. 21 to 23 show the motor rotation of FIG. FIG. 6 is an enlarged view of a blade trailing edge portion 9 in an AA cross section, a BB cross section, and a CC cross section perpendicular to the shaft 8. Similar to the fifth embodiment, the shape changes from the hub 3 side toward the shroud 5 side, but the outlet angle β2a on the pressure surface side is constant between the hub 3 and the shroud 5, and the blade pressure surface The inflection point 13 is separated from the blade trailing edge 9 as it goes from the hub side 3 toward the shroud 6 side. That is, the closer to the shroud 5, the higher the effect of increasing the discharge pressure, and the same effect as in the fifth embodiment can be expected.
[0023]
【The invention's effect】
An air conditioner of the present invention includes a turbofan that sucks and discharges air, and a heat exchanger that is disposed on the suction side or discharge side of the turbofan and cools or heats the air. The fan has a shape in which the exit angle on the pressure surface side of the blade is larger than the exit angle on the suction surface side in each blade cross section perpendicular to the motor rotation axis. For this reason, it is possible to increase the discharge pressure by increasing the outlet angle on the pressure surface side, and to suppress the separation of the air flow on the negative pressure surface side, so that the efficiency can be increased.
[0024]
Moreover, the rotation speed for obtaining the same pressure can be kept low. Therefore, an air conditioner with low blowing sound and high efficiency can be obtained, and when mounted on an indoor unit of an air conditioner, the power consumption of the indoor unit of the air conditioner can be reduced by about 3 to 5%.
[Brief description of the drawings]
FIG. 1 is a partially broken plan view of a turbofan in a first embodiment of the present invention.
FIG. 2 is a longitudinal sectional view of a turbofan in the first embodiment of the present invention.
FIG. 3 is an enlarged view of a blade trailing edge portion of the turbofan in the first embodiment of the present invention.
FIG. 4 is a cross-sectional view of an indoor unit of an air conditioner equipped with a turbo fan according to an embodiment of the present invention.
5 is an enlarged view of a blade trailing edge portion in a BB cross section of A portion in FIG. 4. FIG.
FIG. 6 is a partially broken plan view of a turbofan in a second embodiment of the present invention.
FIG. 7 is an enlarged view of a blade trailing edge portion of a turbofan in a second embodiment of the present invention.
FIG. 8 is a partially broken plan view of a turbofan according to a third embodiment of the present invention.
FIG. 9 is an enlarged view of a blade trailing edge portion of a turbofan in a third embodiment of the present invention.
FIG. 10 is a partially broken plan view of a turbofan in a fourth embodiment of the present invention.
FIG. 11 is an enlarged view of a blade trailing edge portion of a turbofan in a fourth embodiment of the present invention.
FIG. 12 is a schematic diagram showing a flow at a blade trailing edge of a turbofan in a third embodiment of the present invention.
FIG. 13 is a schematic diagram showing a flow at a blade trailing edge of a turbofan in a fourth embodiment of the present invention.
FIG. 14 is a partially broken plan view of a turbofan according to a fifth embodiment of the present invention.
FIG. 15 is a longitudinal sectional view of a turbo fan according to a fifth embodiment of the present invention.
16 is an enlarged view of the trailing edge of the blade in the AA cross section in FIG. 15. FIG.
17 is an enlarged view of a blade trailing edge portion in a BB cross section in FIG. 15;
18 is an enlarged view of the trailing edge of the blade in the CC cross section in FIG.
FIG. 19 is a partially broken plan view of a turbofan according to a sixth embodiment of the present invention.
FIG. 20 is a longitudinal sectional view of a turbofan according to a sixth embodiment of the present invention.
FIG. 21 is an enlarged view of a blade trailing edge portion taken along the line AA in FIG. 20;
22 is an enlarged view of the trailing edge of the blade in the BB cross section in FIG. 20;
FIG. 23 is an enlarged view of the trailing edge of the blade in the CC section in FIG. 20. FIG. 24 is a partially broken plan view of an example of a conventional turbofan.
FIG. 25 is an enlarged view of a blade trailing edge in an example of a conventional turbofan.
FIG. 26 is a schematic diagram showing a flow at a blade trailing edge in an example of a conventional turbofan.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Turbo fan outer periphery 2 ... Boss 3 ... Hub 4 ... Blade 5 ... Shroud 6 ... Direction of rotation 7 ... Motor 8 ... Motor rotating shaft 9 ... Blade rear edge 10 ... Pressure surface 11 ... Negative pressure surface 12 ... Blade 13 ... Inflection Point 14 ... Blade 15 ... Pressure side blade trailing edge 16 ... Negative pressure side blade trailing edge 17 ... Intermediate part 18 ... Blade 19 ... Through hole 20 ... Blade 21 ... Fan outlet 22 ... Blade 23 ... Blade 24a ... Straight line 24b ... Straight line 25a ... Straight line 25b ... Straight line 26 ... Vortex 27 ... Air flow separation 28 ... Cabinet 29 ... Turbo fan 30 ... Heat exchanger 31 ... Bell mouth 32 ... Filter 33 ... Suction grill 34 ... Panel 35 ... Air outlet β2a ... Pressure surface side outlet angle β2b ... Negative pressure surface side outlet angle

Claims (6)

An air conditioner comprising: a blower that sucks and discharges air; and a heat exchanger that is disposed on a suction side or a discharge side of the blower and that cools or heats the air. A disc-shaped boss provided with a hole for mounting the motor rotation shaft, a hub disposed in contact with the outer periphery of the boss, and disposed on the surface of the hub in a circumferential direction around the motor rotation shaft. A turbo comprising a plurality of blades and an impeller made of a shroud disposed on the side facing the hub across the blades, and a motor for fixing the motor rotation shaft to the boss and rotating the impeller In an air conditioner using a fan,
In each blade cross section perpendicular to the motor rotation axis of the turbofan, the outlet angle on the pressure surface side of the front surface on the rotational direction side of the blade is larger than the outlet angle on the suction surface side that is the blade surface on the back surface. An air conditioner characterized by that. 2. The air conditioner according to claim 1, wherein a shape of the pressure surface side of each blade cross section perpendicular to the motor rotation axis of the turbofan is an airfoil. In each blade cross section perpendicular to the motor rotation axis of the turbofan, the shape on the pressure surface side has an inflection point at an arbitrary radius centered on the motor rotation axis, and from the inflection point 2. The air conditioner according to claim 1, wherein the shape of the pressure surface forms a concave curve or a vertical straight line toward the fan rotation direction from the blade trailing edge. In each blade cross section perpendicular to the motor rotation axis of the turbofan, the shape of the pressure surface has an inflection point at an arbitrary radius centered on the motor rotation axis, and the shape of the pressure surface is a blade. 2. The air according to claim 1, wherein an airfoil is formed in a fan rotation direction from a leading edge of the blade toward the inflection point, and a concave curve or a vertical straight line is formed from the inflection point to a trailing edge of the blade. Harmony machine. The blade trailing edge of the turbofan is thinned, and the trailing edge of the blade is divided into two parts that are branched into a pressure surface side and a suction surface side. An air conditioner according to any one of the above. A through hole is provided between an intermediate portion between the blade trailing edge on the pressure surface and the blade trailing edge on the suction surface side and the blade trailing edge on the pressure surface side which are branched into two of the turbofan. Item 6. An air conditioner according to Item 5.

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