JP2000064991A - Air-conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the generation of noise, to improve strength, and to prevent the occurrence of unevenness in a vane mounting angle by a method wherein the maximum value of the chord length of a propeller fan being the electric fan of a heat-exchange part is positioned at the outer peripheral part of the fan and the fan6 outer peripheral part is protruded to the pressure surface side, and the outer peripheral part is moved backward to the negative pressure surface side. SOLUTION: A propeller fan 5 is formed that vanes 2 are disposed at a boss 1. In this case, since an outer peripheral protrusion part 3 protruding from a pressure surface at the tip of the vane 2 has a given curvature, the protrusion part is moved backward to a negative pressure surface after protrusion. The vane shape of a part wherein a fan outer peripheral end formed that it is moved backward to the negative pressure surface side at an outer peripheral part and a fan front edge cross each other is changed in a manner to protrude toward the pressure surface side. Further, a maximum outside diameter part is arranged further near the front edge side than the central part (, for example, 50% of a chord flare) of the vane. The outside diameter D21 is set to a value, for example, 3% or more higher than an outside diameter D23. This constitution increases an air volume without increasing the generation of noise.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an air conditioner such as a room air conditioner or a package air conditioner, and more particularly to a propeller fan used for an outdoor unit and a unit structure.

[0002]

2. Description of the Related Art In recent years, power saving of air conditioners has become an indispensable subject due to problems such as the global environment. In order to achieve power saving, it is necessary to increase the heat exchange capacity for the same electric input. As one element of this capacity increase, it is necessary to increase the amount of radiated air from the outdoor unit especially in the cooling operation or the heating operation. That is, it is necessary to increase the air volume of the blower fan in the outdoor unit.

In general, there are means for increasing the fan speed or increasing the fan outer diameter in order to increase the air volume. However, when the fan speed is increased, the logarithm of the sixth power of the fan speed is increased. And the input also increases in proportion to the cube of the rotation speed. Increasing the fan outer diameter has a problem that, for example, the outdoor unit itself becomes large. For this reason, if a large air volume can be obtained without changing the fan outer diameter, it is possible to increase the air volume by increasing the rotation speed by the lower noise,
It can contribute to the power saving of air conditioners.

[0004] As conventional techniques for reducing the noise of a propeller fan, Japanese Patent Publication No. 6-46039 (Document 1) and Japanese Patent Application Laid-Open No. 6-173895 (Document 2) are known. Further, when a propeller fan is mounted on a unit and the size of the unit is not sufficiently large with respect to the fan, Japanese Patent Laid-Open No. 1-131835 discloses a conventional technique for preventing an increase in noise due to backflow in the propeller fan. (Reference 3) is known.

[0005] Literature 1 discloses a fan provided with a bent portion on the outer periphery of the fan in order to prevent the flow from leaking from the pressure surface to the negative pressure surface at the tip of the fan, causing separation and causing high sound. Patent Document 2 discloses a fan having a thick pressure surface at the outer peripheral end.

[0006]

The prior art described in Document 1 discloses a curl blade having a fan radius greater than or equal to a predetermined fan radius at the outer peripheral end of the fan, which is once protruded to the pressure surface side and retreated to the suction surface side. It is intended to reduce the noise by reducing the local flow velocity of the leakage flow from the surface to the negative pressure surface. However, since the tip curl blade actively generates leakage, the noise can be reduced, but the air volume decreases at the same rotation speed, and as a result, the fan rotation speed must be increased,
The noise reduction effect cannot be achieved with the same air volume. Reference 1
Is M in which the pitch ratio of the blades is continuously increased with the radius of the fan in the tip curl blade. However, factors that increase the pitch ratio are the blade shape radius (r) and the blade attachment angle (Θ). To increase the pitch ratio, either increase the blade shape radius (r) or increase the blade attachment angle (Θ). ) Needs to be smaller. this is,
The larger the fan outer diameter, the less the turning of the inflowing air, and the higher the pressure is not expected. Therefore, no consideration is given to providing a fan having a high peripheral speed and capable of increasing the pressure.

[0007] The dimensionless pitch ratio described in Document 1
Radial optimal distribution of dimensionless projection width (the dimensionless pitch ratio is large where the fan outer diameter is large,
This indicates that the wing is twisted in the rotation direction), and it can be seen that the pressure hardly increases at the outer peripheral portion. This seems to be due to a boundary condition in use that the fan is mounted near the upstream of the engine for cooling, so that radial flow must be expected at the outer peripheral portion of the fan.

[0008] The noise reduction technique described in Document 2 is intended to reduce the noise by reducing the local flow velocity of the leakage flow flowing out of the blade tip by projecting the thickness distribution of the blade at the outer peripheral end of the fan to the pressure surface side. is there. However, no means is described for compensating for the noise reduction effect and the reduction of the fan air volume. In addition, it is a means to solve the problem of stress concentration due to sink at the blade tip at the time of forming, and variation in aerodynamic performance due to change in blade mounting angle, which occurs due to changing the blade tip thickness distribution at the outer peripheral end with a large chord length. They were not mentioned.

In the noise reduction technology of Document 3, the propeller fan is hardly mounted on the unit with low noise and optimal boundary conditions. For example, an electric appliance storage box is arranged on the upper part of the fan, and a compressor cover is arranged on the side. Is done. In this case, since the suction space is narrow in the outer peripheral portion of the fan, the static pressure drops rapidly, and a backflow from the discharge side occurs, which is sucked into the propeller fan and the noise often increases greatly. The above-mentioned reduction technology is based on the assumption that one of the causes is that the upstream flow fluctuates due to backflow.In order to prevent this fluctuation, the purpose is to install a guide piece in a part where the unit bottom bottom fluctuates greatly and stabilize the flow. It was done.
However, although it is said that it is effective to install one end of the guide piece toward the outer peripheral end of the propeller fan, the backflow in the high-density mounting unit extends not only to the outer peripheral end of the fan but also to the front edge side. In such a case, there is a problem that the guide piece position disclosed in the above reduction technique has no effect.

[0010] An object of the present invention is to provide a propeller fan, which has a problem in a propeller fan in which a large noise reduction is performed by reducing a local flow velocity of a leakage flow at an outer peripheral end of the fan. It is an object of the present invention to provide an air conditioner in which noise is reduced by reducing the effects, improving the strength of the outer peripheral end of the fan, and dispersing the blade mounting angle when molding the fan. Another object of the present invention is to provide an air conditioner with a high air volume and a low power consumption by preventing noise from increasing when mounted on a unit even if the fan is a quiet propeller fan alone.

[0011]

In order to achieve the above object, an air conditioner according to the present invention comprises an air conditioner having a propeller fan as a blower of a heat exchange section for exchanging heat between refrigerant and air. In the machine, the maximum value of the chord length of the propeller fan is located substantially on the outer periphery of the fan,
In a fan formed so that a portion near the outer periphery of the fan protrudes toward the pressure surface side and retreats toward the suction surface side at the outer peripheral portion, the outer diameter dimension of the leading edge side from the center of the blade at the outer peripheral edge of the fan is the outer diameter of the leading edge or trailing edge. It is formed so as to be larger than the size, and the portion near the fan outer periphery that protrudes toward the pressure surface side near the outer periphery of the fan and retreats toward the negative pressure surface side at the outer periphery portion has a blade shape at the intersection of the fan outer edge and the fan front edge. It is formed so as to protrude toward the surface or to increase the blade thickness of the portion toward the pressure surface.

[0012] Further, the above object is to provide a heat exchanger unit for exchanging heat between refrigerant and air, wherein the unit is provided between a heat exchanger and a propeller fan in a unit of an air conditioner having a propeller fan as a blower. The inner air passage section is formed to be long in the frontage direction of the air passage section, one end is fixed to the air passage wall surface side, and the other end side is upstream of the fan from the fixed position and the lowermost end of the fan outer peripheral end. This is achieved by installing a guide piece that is raised above the point.

A further object of the present invention is to dispose a heat exchanger on the suction side of the propeller fan and an electric equipment storage box for storing electric equipment on the upper part of the propeller fan. In an outdoor unit of an air conditioner in which a radiating fin for radiating electric components is disposed on an end side, a mouth ring which is disposed on a side where the radiating fin is disposed and is paired with a propeller fan substantially below the radiating fin. A part of it is projected in the direction of the rotation axis of the propeller fan,
Alternatively, this is achieved by providing a flow deflector that protrudes in the axial direction of the propeller fan in a part of the mouth ring.

Further, the above object is achieved by an air conditioner equipped with at least two or more of the first, second and third aspects.

[0015]

FIG. 1 is a block diagram showing an embodiment of the present invention.
This will be described with reference to FIG. A first embodiment will be described with reference to FIGS.

FIG. 1 is a side view of a propeller fan according to an embodiment of the present invention. a, FIG. b, FIG. c, FIG. d is a sectional view taken along each arrow in FIG. FIG. 2 is a graph of air volume and noise characteristics with respect to the number of rotations, comparing the propeller fan of the present embodiment with the conventional art.

FIG. 1 is a side view of a propeller fan used in an outdoor unit of a room air conditioner. In the propeller fan shown in FIG. 1, a plurality of blades 2 are arranged on a boss 1. When the wing 2 rotates, air is sucked in from the right side in the figure and is blown out to the left side. That is, the visible surface of the upper wing 2 is a pressure surface, the visible surface of the lower wing 2 is a negative pressure surface, and the right side in the figure is the leading edge of the wing 2 and the left side is the trailing edge of the wing 2. As will be described later with reference to FIGS. 3, 4, and 5, in an outdoor unit employing this propeller fan, a mouth ring 14 is provided on the outer periphery of the fan, a heat exchanger 11 is provided upstream, a fan motor 13 and an electrical component 1 are provided.
5, compressor 22, refrigeration cycle parts, etc. are installed.

Outer peripheral projection 3 projecting from the pressure surface at the tip of blade 2
Since it has a curvature as will be described later, it does not appear on the drawing but retreats to a negative pressure surface after protruding. Outer diameter ΦD2 shown
1, ΦD22, ΦD23, ΦD24 are formed so that the fan maximum outer diameter, the leading edge side outer diameter, the trailing edge side outer diameter, and further, the portion near the fan outer periphery protrudes to the pressure surface side, and the outer periphery portion recedes to the negative pressure surface side. The blade shape at the intersection of the fan outer peripheral edge and the fan leading edge is changed so as to protrude toward the pressure surface side. Or, it shows the minimum diameter that changes from the conventional blade shape in the case where the blade thickness of the portion is increased on the pressure surface side. FIG. a,
FIG. b, FIG. c, FIG. d shows a sectional view taken along each arrow. FIG. 1 is a cross section of the trailing edge of the fan. The shape of the outer peripheral protruding portion 3 can be seen from a. The outer diameter ΦD23 is set to 100%. Fig. 1 is a cross-sectional view of the maximum outer diameter portion of the fan. Shown in b. The maximum outer diameter portion is on the leading edge side of the center of the blade near the outer periphery of the fan (at 50% of the chord length), and its outer diameter ΦD21 is 3% or more larger than the outer diameter ΦD23 on the trailing edge side. The basis is that a 3% change in the fan outer diameter increases the airflow by about 10% at the same rotation speed (when the airflow is increased by increasing the rotation speed, the sound volume increases by about 3dB),
Since the sound is increased by at most 0.8 dB, an increase in the outer diameter has an effect of about 2 Db.

FIG. c shows a sectional view taken along the front edge side arrow. The leading edge side outer diameter ΦD22 is also smaller than the maximum outer diameter.
In the leading edge portion of the wing 2 and in the vicinity of the projecting portion 3, a thick leading edge projecting portion 4 is formed on the pressure surface side. In the figure, the leading edge protruding portion 4 has a larger blade thickness, but may have a shape that protrudes toward the pressure surface with a substantially uniform blade thickness like the outer peripheral protruding portion. FIG. d shows the shape of the leading edge protruding portion 4 for easy understanding. The leading edge protruding portion 4 is not the entire radial direction of the wing 2 (to prevent deformation at the time of molding), and is approximately 7
Provide at 0% or more. The basis is that the main sound source of the propeller fan is represented by a radius of about 80% or more of the outer diameter of the fan having a high peripheral speed, so that it is sufficient to take low-noise measures from the vicinity thereof to the outer peripheral portion. As described above, the maximum outer diameter is at the leading edge side from the center of the wing, and by reducing the outer diameter at the leading edge, the influence of the leading edge, which is the main sound source (the peripheral speed of the leading edge is assumed to be the same as before), is avoided. However, while the outer diameter is increased in the middle of the blade, the fan's original characteristic, that is, the air volume is proportional to the cube of the outer diameter, while the noise is only proportional to the logarithm of the outer diameter to the sixth power, is low. Providing a protruding portion at the leading edge prevents noise from coming off at the outer peripheral portion of the leading edge, thereby achieving an effect of reducing noise.

FIG. 2 shows a conventional fan (a fan having a protruding portion at the outer peripheral end of the fan, but having a constant outer diameter of the fan and not having a protruding portion at the front edge) and the air flow rate with respect to the rotation speed of the fan of the present embodiment. Shows noise characteristics. The figure shows that the fan of the present embodiment has a good result that the air volume increases by 7% and the sound hardly increases at the same rotation speed.

FIGS. 3, 4, and 5 show another embodiment of a room air conditioner outdoor unit equipped with the propeller fan of the above embodiment. FIG. 3 is a cross-sectional view of the outdoor unit according to the embodiment, FIG. 4 is a cross-sectional view taken along the line AA of FIG. 3, and FIG. 5 is a cross-sectional view taken along the line BB of FIG. In FIG. 3, boss 1, wing
2, propeller fan 5 consisting of outer peripheral projection 3, leading edge projection 4
Are fixed and supported by the motor 13, the motor support base 12, and the motor support base fixing part 19, and rotate. Propeller fan 5
Has an enlarged mouth ring 14 and a mouth ring 21 on its outer periphery. Downstream, a front grille 7 composed of a curvature grill bar 8 and a straight grill bar 9 is arranged to blow the swirling flow of the fan out of the unit with low pressure loss.

An electric appliance storage box 15 is provided above the propeller fan 5, and a radiation fin for promoting cooling of the electric appliances is provided below the box.
17 are installed. Unit 6, Unit top cover 1
A heat exchanger 13 is also installed in the interior constituted by 0 and the like upstream of the propeller fan 5. In FIG. 4, propeller fan 5
A compressor cover 23 is provided on the left side of the compressor, and a compressor 22, and cycle components (not shown) are mounted therein.
Further, FIGS. 3, 4 and 5 show that the static pressure on the suction side of the propeller fan 5 (the flow path between the heat exchanger 11 and the mouth ring 21) is not sufficient because the flow path around the propeller fan 5 is not sufficient. The guide piece is fixed by a fixing screw 18 in order to prevent the reverse flow from being sucked into the fan again while changing with time and increasing the noise.
As can be seen from FIGS. 3, 4, and 5, one end of the guide piece is fixed to the flow path wall on the inner surface of the unit, and the other end is directed from the outer peripheral projection 3 to the front edge projection 4 of the propeller fan 5. It is installed in. The length in the frontage direction of the guide piece 16 is set to a value of 0.4 to 0.6 of the fan outer diameter. Further, although the guide piece 16 is fixed to the unit bottom surface with a screw 18 in the drawing, it may be formed integrally with the motor support base 12. FIGS. 3, 4 and 5 show a mouth ring in order to prevent the separated flow from the radiating fins 17 from flowing into the fan and generating a blade sound (a sound that is dominant at the frequency of the number of blades × the number of rotations). A deflecting plate 20 which is a part of the circumferential direction of the fin and protrudes below the radiation fins 17 is provided. In the figure, it is fixed as a separate part by the deflection plate fixing screw 24, but it is also possible to integrally mold the outer peripheral portion of the mouth ring 21.

The function and effect of the guide piece 16 will be described. When the propeller fan 5 is mounted in a relatively large unit, the static pressure of each suction unit is uniform, there is no backflow from the mouth ring 21, and a high air volume can be realized very quietly. However, it is better that the size of the unit is small in consideration of the installation space and the like. Therefore, for the propeller fan 5, the static pressure in the unit is locally reduced (particularly in a narrow portion of the flow path) and does not normally occur because the propeller fan 5 attempts to perform its function in a situation where the flow path around the fan is insufficient. Backflow occurs from the stage of unit installation. This backflow does not fit in a part of the outer peripheral portion of the propeller fan 5 as shown in Document 3, but also extends to the leading edge portion. Normally, if the backflow is constant over time, the noise does not increase significantly, but if the backflow reaches the front edge of the fan at a certain time from the outer periphery, the relative inflow speed into the fan changes greatly, Is fluctuated in time and increases. The guide piece 16 prevents the temporal change from the suction of the fan outer circumference to the suction of the leading edge (by fixing the flow) so that the noise does not increase.

Next, the function and effect of the deflection plate 20 will be described. Compressor 22 at one end of the unit and heat exchanger 1 at the other end
1, In a typical unit configuration in which the electrical equipment storage box 15 is further arranged at the top, the heat radiation fins 15 for cooling the electrical equipment are installed on the side opposite to the compressor 22 at the heat exchanger part bent at almost 90 degrees Is done. In addition, in order to maximize the heat radiation characteristics from the direction of air flow to the propeller fan, a heat radiation fin 17 is provided from the unit back to the unit front as shown in FIG. In such a case, the radiation fins 17 impede the flow from the side of the unit, that is, obstruct the inflow flow (see FIG. 4). When the propeller fan 5 rotates, the inflow is small at the portion of the radiating fin 17 that is the longest from the electrical appliance storage box 15 portion, whereas the inflow air is large at the right side of the portion of the longest radiating fin 17. In such a case, the propeller fan 5 is likely to generate a blade sound at a portion where the inflow speed greatly changes with rotation, and the level of the sound may be high enough to control the entire noise. The deflection plate 20 protrudes from the lower part of the heat radiation fin 17 and the outer peripheral portion of the mouth ring 21 so as to change locally and in the rotation direction of the fan so that the flow does not change suddenly. This has the effect of suppressing rapid changes in flow. In the figure, the deflecting plate 20 is a rigid body, but a mesh-like or comb-tooth-like body that can apply resistance to the flow has a further effect.

FIG. 6 shows the state of generation of the blade sound in the unit equipped with the propeller fan 5, the guide piece 16, and the deflecting plate 20 of the present invention and the conventional unit. In the present embodiment, it can be seen that the effect is exhibited up to the first to fifth order of the blade sound, and even higher order components (not shown).

[0026]

According to the present invention, there is a problem in a propeller fan in which noise is reduced by locally reducing the flow velocity of a leakage flow at the outer peripheral portion of the fan. It can solve the problem of blade mounting angle variation at the time of fan molding, and can also provide a power-saving and low-noise air conditioner by preventing the noise of the propeller fan from increasing when the propeller fan is mounted on the unit. .

[Brief description of the drawings]

FIG. 1 is a side view of a propeller fan according to an embodiment of the present invention.

FIG. 2 is a graph of air volume and noise characteristics with respect to the number of rotations, comparing the propeller fan of the present embodiment with a conventional technology.

FIG. 3 is a sectional view of an outdoor unit showing one embodiment of the present invention.

FIG. 4 is a cross-sectional view of the outdoor unit of FIG.

FIG. 5 is a cross-sectional view of the outdoor unit of FIG.

FIG. 6 is a frequency characteristic diagram illustrating a sound pressure level with respect to a frequency when the unit of the embodiment of FIG. 3 is compared with a conventional technology.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Boss, 2 ... Wings, 3 ... Outer peripheral protrusion, 4 ... Leading edge protrusion,
5 ... propeller fan, 6 ... unit, 7 ... front grill,
8: curved grill bar, 9: straight grill bar, 10: unit upper cover, 11: heat exchanger, 12: motor indicator, 1
3 ... Motor, 14 ... Enlarged mouse ring, 15 ... Electric goods storage box, 16 ... Guide piece, 17 ... Heat radiation fin, 18 ... Guide piece fixing screw, 19 ... Motor support base fixing part, 20 ... Deflection plate, 21 ... Mouse Ring, 22: compressor, 23: compressor cover, 24: deflection plate fixing screw.

Continuing on the front page (72) Inventor Shinya Yoshinaga 800, Tomita, Odaimachi, Ohira-machi, Shimotsuga-gun, Tochigi Prefecture Inside the Cooling Division, Hitachi, Ltd. (72) Inventor Hidenori Yokoyama 800, Tomita, Odaira-cho, Shimotsuga-gun, Tochigi Hitachi, Ltd. Within the business department (72) Inventor Motoo Morimoto 800, Tomita, Ohira-cho, Ohira-machi, Shimotsuga-gun, Tochigi Prefecture Within the Refrigeration and Heating Division, Hitachi, Ltd. (72) Inventor Susumu Susumu Hamada 709, Oda-machi, Ohira-cho, Shimotsuga-gun, Tochigi 2 Hitachi Tochigi, Ltd. Inside the electronics (72) Inventor Masami Murayama 709 Tomita, Ohira-cho, Ohira-machi, Shimotsuga-gun, Tochigi Prefecture Inside of Hitachi Tochigi Electronics Co., Ltd. (72) Shoji Takahisa 800 Tomita, Ohira-cho, Shimotsuga-gun, Tochigi Prefecture Internal F-term (reference) 3H033 AA02 AA18 BB02 BB08 BB20 CC01 CC03 CC04 DD03 DD06 DD19 DD23 DD29 DD30 EE05 EE06 EE08 EE11 EE19 3H035 CC01 CC04 CC07

Claims (1)

[Claims] 1. An air conditioner having a propeller fan formed so that an outer peripheral portion of a blade protrudes toward a pressure surface and air recedes to a negative pressure surface side at the outer peripheral portion. A fan outer periphery formed such that the outer diameter dimension of the leading edge side is larger than the outer diameter dimension of the leading edge or the trailing edge, and the outer peripheral portion of the fan protrudes to the pressure surface side and the outer peripheral portion is receded to the negative pressure surface side. An air conditioner with the blade thickness at the intersection of the end and the front edge of the fan protruding toward the pressure surface.