JP2003269363A - Tangential fan impeller and air conditioner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tangential fan impeller which effectively reduces discrete frequency noise, and to provide an air conditioner using this tangential fan impeller. <P>SOLUTION: (1) Respective blades 31 are collected into even number groups having mutually the equal number of sheets, and adopt the constitution having a pitch difference angle ε becoming β=α+ε and γ=α-ε when a virtual average pitch angle is set to α, a pitch angle between the respective blades in adjacent one group among the respective groups is set to β, and a pitch angle between the respective blades in the other group is set to γ. (2) Respective blocks are dislocated by an angle γ in the shaft direction, and are adjacently joined, and are dislocated by an angle δ for minimizing synthetic sound pressure of an NZr component wave of the respective blocks to form an arrangement fan. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a tangential fan impeller suitable for use in, for example, an indoor unit of an air conditioner, and an air conditioner equipped with this tangential fan impeller.

[0002]

2. Description of the Related Art FIG. 5 shows an example of an air conditioner equipped with a conventional tangential fan impeller of this type. In addition,
FIG. 1 is a vertical sectional view showing an indoor unit of a conventional air conditioner. In the indoor unit shown in the figure, a box-shaped housing (hereinafter referred to as a casing 3) is formed by combining a front panel 2 with a base 1. The front panel 2 has air suction ports 4, 5 and 6 formed on the front and upper surfaces thereof.

In the casing 3, a plate fin tube type indoor heat exchanger 7 and a tangential fan impeller 8 which is a cross flow fan are arranged. The tangential fan impeller 8 has a configuration in which a plurality of blades are annularly arranged to form a cylinder, and the cylinder is reinforced at a plurality of positions in the axial direction (direction perpendicular to the plane of the drawing) by interstitial plates perpendicular to the axial line. It is provided and is disposed in the air passage case 1A inside the casing 3. The blades are arranged at equal pitch angular intervals with respect to the axis.

The indoor heat exchanger 7 has a structure in which a plurality of plate fins are arranged in parallel, side plates are arranged on both sides of the plate fins, and a tube through which a refrigerant flows is arranged between the side plates and the plurality of plate fins. I am doing it.
The indoor heat exchanger 7 is arranged so as to surround the tangential fan impeller 8 on the air intake side when the tangential fan impeller 8 rotates in the direction indicated by the arrow a in the figure. ing. The indoor heat exchanger 7 is divided into three parts, that is, a first stage part 7a, a second stage part 7b, and a third stage part 7c. On the other hand, front panel 2
The air outlet 2a is provided with a wind direction changing device 9 that changes the blowing directions of cold air and warm air.

The tangential fan impeller 8 is also provided.
A nose 1a and a stabilizer 1b are provided integrally with the base 1 on the air intake side. The stabilizer 1b also serves as a drain guide for receiving drain (condensate) generated in the indoor heat exchanger 7, and is parallel to the outer peripheral surface of the tangential fan impeller 8 with a predetermined gap. It is almost flat.

When the tangential fan impeller 8 rotates in the direction indicated by the arrow a, the ambient air causes the front panel 2 to move.
Is sucked from the air suction port 4 on the front surface and the air suction ports 5 and 6 on the upper surface, and is sent to the first to third stage portions 7a to 7c of the indoor heat exchanger 7. Then, the air is heat-exchanged in the first to third stage portions 7a to 7c of the indoor heat exchanger 7, and the obtained cool air or warm air K is driven by the tangential fan impeller 8 to draw in the suction side described above. Becomes a flow in the direction shown by the arrow in the drawing across the tangential fan impeller 8 and is then blown from the air outlet 2a. At this time, the blowing direction of the cold air or the warm air K is changed by the wind direction changing device 9.

[0007]

The air conditioner having the conventional tangential fan impeller 8 described above has the following problems. That is, when the number of each of the blades is Zr and the number of rotations of the tangential fan impeller 8 is N rotations per second, the periphery thereof is
This is a problem that pure tone noise is generated due to the regular pressure fluctuations because the pressure fluctuations occur NZr times per second regularly.

As shown in FIG. 6, the blast noise of a tangential fan impeller is generally a wide band frequency noise that is gently distributed in a wide band and a discrete frequency noise (pure tone) having a peak at a single frequency.・ Noise or NZ
Called sound. ) And. Broadband frequency noise is turbulent noise that is mainly caused by turbulence in the wake of the heat exchanger and separation of flow from each blade, and has a wide frequency band.
The sound pressure level is relatively low. On the other hand, the discrete frequency noise is a relatively high frequency noise having a remarkable peak at a frequency (1NZr, 2NZr, 3NZr) that is an integral multiple of the NZr as a fundamental frequency, and is a noise source that is easy to hear. . The level of this discrete frequency noise has a smaller contribution ratio of the flow velocity than that of the broadband frequency noise, and is likely to be remarkable during low air volume operation. Air conditioner
Although it is also used in the bedroom, it is essential to suppress the discrete frequency noise in order to reduce the noise in the low noise mode used at bedtime.

As a means for suppressing this discrete frequency noise, there is a random pitch fan that makes the arrangement of the blades unequal intervals. This is a method of making the period of the sound source irregular by making the array pitch of the blades non-uniform according to a random normal distribution, and dispersing the blade pitch sound into a plurality of low peaks. However, in this case as well, 1NZr, 2NZr, 3N
It is the same that a remarkable peak waveform is generated at each frequency of Zr, the peak level does not decrease as much as expected, and further noise countermeasures are desired.

The present invention has been made in view of the above circumstances, and provides a tangential fan impeller capable of effectively reducing discrete frequency noise and uses the tangential fan impeller. The purpose is to provide the air conditioner that was used.

[0011]

The present invention adopts the following means in order to solve the above problems. That is, the tangential fan impeller according to claim 1 forms a cylinder by annularly arranging a plurality of blades around a rotation axis, and the rotation thereof causes the fluid introduced inside to be blown out to the outside. In the impeller, when the number of blades is an even number, the blades are grouped into an even group having the same number of blades, and when the number of blades is an odd number, one of them is grouped. Except for
Grouped into an even number of groups with the same number of sheets, 3
The virtual average pitch angle obtained by dividing 60 ° by the total number of blades is α, and the pitch angle between blades in one of the adjacent groups is β, and the pitch angle between blades in the other group is β. If γ, β =
It is characterized by having a pitch deviation angle ε such that α + ε and γ = α−ε. According to the tangential fan impeller according to claim 1, when the NZr component sound pressure is obtained by Fourier integration, the waveform component of the group having the pitch angle β is also the waveform component of the group having the pitch angle γ. Also has a pitch shift angle ε with the waveform of the NZr component, a phase difference occurs with the waveform of the NZr component in the time axis direction. Therefore, even if the Fourier integral value of the NZr component is a γ group wave, Even in the case of waves, they cancel each other out and decay.

A tangential fan impeller according to a second aspect is the tangential fan impeller according to the first aspect, wherein the pitch deviation angle ε is 0 <ε ≦.
It is characterized by being 0.1α. According to the tangential fan impeller described in claim 2, the pitch shift angle ε needs to be 0 or more in order to obtain the effect of damping the discrete frequency noise. Further, in order to prevent the ventilation characteristics of the tangential fan impeller from being extremely deteriorated, it is necessary to set the pitch deviation angle ε to 0.1α or less.

The tangential fan impeller according to claim 3 is the tangential fan impeller according to claim 1 or 2, wherein the number of divisions of each group is two. Is characterized by. According to the tangential fan impeller according to the third aspect, it is possible to obtain the most effective attenuation of the discrete frequency noise, though it is simple, as compared with the case where it is divided into three or more.

A tangential fan impeller according to a fourth aspect is the tangential fan impeller according to any one of the first to third aspects, wherein each of the blades extends in the direction of the rotation axis. It is characterized in that it is divided into a plurality of blocks and the relative position is shifted by δ between adjacent blocks. According to the tangential fan impeller according to claim 4, when the displacement angle δ is calculated so as to synthesize the sound pressures in the rotation axis direction and give the minimum value of the sum, one of the blocks The waveform component and the waveform component of the other block have approximately approximately opposite phases, and the peaks and troughs of the waveform components of both blocks cancel each other out and attenuate.

The tangential fan impeller according to a fifth aspect is the tangential fan impeller according to the fourth aspect, wherein the relative position deviation δ between the adjacent blocks is 180 ° ±. It is characterized in being in the range of β / 2 °. According to the tangential fan impeller described in claim 5, in each block, the concentration density of the mass of each blade centered on the rotation axis is sparse or dense (group with pitch angle γ). Since it is divided into two groups (group with pitch angle β), a weight imbalance occurs, but by setting the relative position deviation between these blocks to 180 ° ± α / 2 °, it is possible to You will be able to cancel out the imbalance.

An air conditioner according to a sixth aspect of the present invention comprises an indoor unit and an outdoor unit, the indoor unit of the fan except for the fan and the air passage for sending air from the fan. The indoor unit includes an indoor heat exchanger arranged around it, and a stabilizer arranged between the indoor heat exchanger and the fan so as to receive a drain generated in the indoor heat exchanger, and the outdoor unit is an outdoor heat exchanger. An air conditioner comprising: a compressor for sending out a high-temperature and high-pressure gas refrigerant to the indoor heat exchanger; and an outdoor unit control section including various electric circuit elements, wherein the fan serves as the fan. The tangential fan impeller according to any one of 1 to 3 is provided. According to the air conditioner of the sixth aspect, since the tangential fan impeller can effectively reduce the discrete frequency noise, it is possible to significantly reduce annoying operation noise.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of an air conditioner equipped with a tangential fan impeller of the present invention will be described below with reference to the drawings, but the present invention is construed as being limited thereto. Of course not. First, the overall configuration of the air conditioner will be described below with reference to FIG. It should be noted that FIG. 1 is a perspective view showing an indoor unit of the present embodiment and an air conditioner including the indoor unit.

The air conditioner shown in FIG.
0 and the outdoor unit 20. The indoor unit 10 and the outdoor unit 20 are connected to each other by a refrigerant pipe 21 through which a refrigerant conducts, an electric wiring (not shown), or the like. Two refrigerant pipes 21 are provided, and the refrigerant is
On the other hand, from the indoor unit 10 to the outdoor unit 2
0, and on the other hand from the outdoor unit 20 to the indoor unit 10.

The indoor unit 10 has substantially the same structure as that described in the prior art with reference to FIG.
Differences from the conventional one will be described later, and other configurations are the same as those of the indoor unit described in FIG. 5, so description thereof will be omitted here.

The outdoor unit 20 is provided with an outdoor heat exchanger 20b, a propeller fan 20c, a compressor 20f, an outdoor unit controller 20g, etc. in a housing 20a. The outdoor heat exchanger 20b is composed of a refrigerant pipe provided with a large number of plate-shaped fins around it, and is for realizing heat exchange between the refrigerant and the outdoor air. The propeller fan 20c creates a flow of air that escapes from the back surface to the front surface within the housing 20a, so that new air is constantly taken into the housing 20a and the heat exchange efficiency in the outdoor heat exchanger 20b is improved. It is provided for.

The compressor 20f is a low-temperature low-pressure gas refrigerant,
It converts into a high-temperature and high-pressure gas refrigerant and discharges it, and plays the most central role among the components that make up the refrigerant circuit. By the way, the refrigerant circuit is this compressor 20f
In addition to the indoor heat exchanger 7, the outdoor heat exchanger 20b,
A circuit that is roughly configured of a refrigerant pipe 21, an expansion valve, and a four-way valve that defines the flow direction of the refrigerant (both the expansion valve and the four-way valve are not shown), and circulates the refrigerant between the indoor unit 10 and the outdoor unit 20. Is. Outdoor unit controller 20
Reference numeral “g” controls the operation of the propeller fan 20c, the compressor 20f, and other various devices provided in the outdoor unit 20, and is composed of various electric circuit elements.

The operation of the air conditioner having these configurations will be described below separately for each of the heating operation and the cooling operation. First, during the heating operation, the refrigerant made into a high temperature and high pressure gas by the compressor 20f is sent to the indoor heat exchanger 7 of the indoor unit 10 through the refrigerant pipe 21. In the indoor unit 10, heat is applied to the indoor air taken in from the front panel 2 by the tangential fan impeller 8 from the high-temperature and high-pressure gas refrigerant passing through the indoor heat exchanger 7. As a result, warm air is blown out from the air outlet 2a. At the same time, the high-temperature and high-pressure gas refrigerant is condensed and liquefied in the indoor heat exchanger 7,
It becomes a high temperature and high pressure liquid refrigerant.

This high-temperature and high-pressure liquid refrigerant is again supplied to the refrigerant pipe 2.
1 through the outdoor unit 20 in the outdoor heat exchanger 20
sent to b. In the outdoor unit 20, a low-temperature low-pressure liquid refrigerant is passed through an expansion valve (not shown) to become a low-temperature low-pressure liquid refrigerant. The liquid refrigerant takes heat. The low temperature and low pressure liquid refrigerant is
This evaporates and becomes a low-temperature low-pressure gas refrigerant. This is again sent to the compressor 20f, and the above process is repeated.

Next, during the cooling operation, the refrigerant flows in the refrigerant circuit in the opposite direction to the above. That is, the refrigerant made into a high temperature and high pressure gas in the compressor 20f is sent to the outdoor heat exchanger 20b through the refrigerant pipe 21 and gives heat to the outdoor air to be condensed and liquefied to become a high temperature and high pressure liquid refrigerant. The high-temperature high-pressure liquid refrigerant passes through an expansion valve (not shown) to become a low-temperature low-pressure liquid refrigerant, and is sent to the indoor heat exchanger 7 again through the refrigerant pipe 21. Here, the low-temperature low-pressure liquid refrigerant takes heat from the room air to cool the room air, and the refrigerant itself evaporates and becomes a low-temperature low-pressure gas refrigerant. This is the compressor 20 again
Then, the above process is repeated.

These operations are performed by the indoor unit controller 15 and the outdoor unit 20 housed in the indoor unit 10.
The outdoor unit control section 20g housed inside cooperates with each other to perform control.

The following is a characteristic part of this embodiment,
An explanation centered on the tangential fan impeller is shown in FIG.
-The following is performed with reference to FIG. In the following description, a new reference numeral 30 is given to the tangential fan impeller of the present embodiment in order to distinguish it from the conventional tangential fan impeller 8. 2. FIG. 2 is a front view showing the tangential fan impeller 30 provided in the indoor unit 10 of this embodiment.
3A is a sectional view taken along the line AA of FIG.
(B) is a BB sectional view of FIG. Further, FIG. 4 is a graph showing the pitch interval distribution between each blade in a single block, where the horizontal axis is the number of each blade of the tangential fan impeller and the vertical axis is the pitch angle between adjacent blades. Is shown.

As shown in FIGS. 2 and 3, the tangential fan impeller 30 of the present embodiment forms a cylinder by arranging, for example, 35 (plurality) blades 31 in an annular shape around the rotation axis CL. It is an impeller that blows out the fluid introduced inside due to its rotation. Further, each blade 31 of this impeller is divided into a plurality of blocks 33 in the rotation axis CL direction (longitudinal direction) via each interstitial plate 32.

In each of these blocks 33, as shown in FIG. 3, each of the blades 31 except for one of the 35 blades has two equal numbers of 17 blades (even number). Groups 34 and 35. The number of blades 31 of each of these groups 34 and 35 is 360 °, which is the total number of blades 31.
The virtual average pitch angle divided by 5 is α = 10.3 °,
When the pitch angle between the blades 31 in one of the adjacent groups 34 of the groups 34 and 35 is β and the pitch interval between the blades 31 in the other group 35 is γ, β = α + ε and It has a pitch shift angle ε such that γ = α−ε. That is, each blade 31 is divided into two groups, a sparse group 34 having a wider pitch angle β than that of the equal pitch angle and a dense group 35 having a narrower pitch angle γ than that of the equal pitch angle. ing.

As the pitch deviation angle ε,
As an angle satisfying 0 <ε ≦ 0.1α, for example, 0.1 ×
10.3 ° = 1.03 ° is adopted. Therefore, the pitch angle β is 10.3 ° + 1.03 ° = 1.
1.33 °, and the pitch angle γ is 10.3
The angle is −1.03 ° = 9.27 °. The pitch angle at the boundary between the groups 34 and 35 is 11.33 ° to 9.27 °, or 9.
It is possible to make a sudden change from 27 ° to 11.33 °, but for example, the transition pitch portion 3 shown in FIG.
It is more preferable to provide 6, 37 at the boundary between both groups 34, 35 from the viewpoint of maintaining the blowing characteristics.

Each transition pitch portion 36, 37 uses vanes 31 located at opposite ends in group 34 and vanes 31 located at opposite ends in group 35 to provide a smooth pitch angle transition between them. This is the part
Only in this portion, the pitch angle between the adjacent vanes 31 gradually changes from 9.27 ° to 11.33 ° or from 11.33 ° to 9.27 °.

As shown in FIGS. 2 and 3, in this tangential fan impeller 30, the relative position of each blade 31 between adjacent blocks 33 is, for example, a combination of NZr component waves of all blocks. The sum is δ = 178 ° with respect to the block displacement angle δ (where δ is the displacement angle between the adjacent blocks 33, and the sum of all blocks of the NZr component waves of each block 33 gives the minimum angle. , This δ
Is preferably selected from the range of 180 ° ± β / 2 °. ) As an example of taking the minimum value in 178
It is staggered. That is, at the position of the group 34 in the one block 33 shown in FIG.
The group 35 in the other block 33 shown in (b) is 1
80-178 = relative positions are determined so that they are adjacent to each other with a deviation of 2 degrees. Such relative positioning is applied between all adjacent blocks 33.

By providing the tangential fan impeller 30 having the configuration described above, the air conditioner of the present embodiment can significantly reduce the discrete frequency noise emitted from the indoor unit 30. ing. That is, the noise (sound pressure) generated by the tangential fan impeller can be obtained by Fourier integration. At that time, in each block 33, the waveform component of the group 34 having the pitch angle β is also the pitch angle. The waveform component of the group 35 having γ also has a phase difference with the NZr component wave in the time axis direction due to the pitch shift angle ε with respect to the NZr component, so in the Fourier integration process for obtaining the sound pressure of the NZr waveform component Both the waves and the γ-group waves are damped by the mountains and valleys canceling each other out.

Further, the sound pressures of all the blocks 33 in the direction of the rotation axis CL are given CL with a block shift angle δ.
When obtained by synthesizing in the direction, since a phase difference having a substantially opposite phase is generated between the waveform component of one block 33 and the waveform component of the other block 33, the peaks and valleys of these waveform components are mutually different. They cancel each other out and become attenuated.

In the tangential fan impeller 30 of the present embodiment described above, each blade 31 is grouped into two groups 34 and 35 having the same number of sheets, and the virtual average pitch angle is set to α, and each group 34, 35. If the pitch angle between the blades in one of the adjacent groups 34 among the 35 is β and the pitch angle between the blades in the other group 35 is γ, the pitch is β = α + ε and γ = α−ε A configuration having a shift angle ε is adopted. According to this configuration, both the waveform components of the group 34 having the pitch angle β and the waveform components of the group 35 having the pitch angle γ are N
The pitch difference angle ε causes a phase difference with the waveform of the NZr component with respect to the waveform of the Zr component, and the Fourier integral value of the NZr waveform component is canceled in both the β group wave and the γ group wave. Since there is such attenuation, it is possible to effectively reduce discrete frequency noise. Therefore, the noise reduction of the indoor unit 10 can be achieved.

In the tangential fan impeller 30 of this embodiment, the pitch deviation angle ε is 0 <ε ≦ 0.1α.
The configuration adopted is According to this configuration, it is possible to achieve both attenuation of discrete frequency noise and maintenance of air blowing characteristics.

Further, the tangential fan impeller 30 of the present embodiment employs a configuration in which the number of divisions of each group 34, 35 is two. According to this configuration, it is possible to most effectively exhibit the effect of reducing discrete frequency noise. Further, as compared with the case where the number of divisions is increased, the design and manufacturing can be facilitated, so that the cost reduction can be achieved.

Further, in the tangential fan impeller 30 of this embodiment, each blade 31 is divided into a plurality of blocks 33 in the direction of the rotation axis CL, and between adjacent blocks 33,
A configuration is adopted in which the relative position of each blade 31 is shifted by δ.
According to this configuration, it is possible to obtain the same effect of reducing the discrete frequency noise even in the rotation axis CL direction of the tangential fan impeller 30. Therefore, further noise reduction can be achieved.

Further, the tangential fan impeller 30 of the present embodiment employs a structure in which the relative position deviation δ between the adjacent blocks 33 is 178 °, that is, δ = 178. According to this configuration, the balance around the rotation axis CL is adjusted, so that the vibration generated when the tangential fan impeller 30 is rotated can be kept within the allowable level.

Further, the air conditioner of the present embodiment adopts a configuration including the tangential fan impeller 30 as its fan. According to this configuration, the tangential fan impeller 30 can effectively reduce the discrete frequency noise, and thus can be a quiet air conditioner in which annoying operation noise is significantly reduced. Although the number of blades 31 is 35 in the present embodiment, the number of blades 31 is not limited to 35, and may be 34 or less, or 36 or more.
Furthermore, the number of rice is not limited to an odd number and may be even number. In the case of this even number of blades, the blades 31 are grouped into an even number group having the same number of blades.

[0040]

According to the tangential fan impeller according to the first aspect of the present invention, the blades are grouped into an even number group having the same number of blades, and 360 ° is divided by the total number of blades. When the average pitch angle is α, the inter-blade pitch angle in one adjacent group in each group is β, and the inter-blade pitch angle in the other group is γ, β = α + ε and γ = A configuration having a pitch deviation angle ε of α-ε is adopted. According to this configuration, both the waveform component of the group having the pitch angle β and the waveform component of the group having the pitch angle γ are NZr.
Due to the pitch shift angle ε with the waveform of the component, a phase difference occurs with the waveform of the NZr component in the time axis direction, and the Fourier integral value of the NZr component cancels each other for both β group wave and γ group wave. Since there is such attenuation, it is possible to effectively reduce discrete frequency noise.

The tangential fan impeller according to claim 2 is the tangential fan impeller according to claim 1, wherein the pitch deviation angle ε is 0 <ε ≦ 0.1.
The configuration that is α is adopted. According to this configuration, it is possible to achieve both attenuation of discrete frequency noise and maintenance of air blowing characteristics.

The tangential fan impeller according to claim 3 is the tangential fan impeller according to claim 1 or 2, wherein the number of divisions of each group is two. It was adopted. According to this configuration, it is possible to most effectively exhibit the effect of reducing discrete frequency noise. Further, as compared with the case where the number of divisions is increased, the design and manufacturing can be facilitated, so that the cost reduction can be achieved.

A tangential fan impeller according to a fourth aspect is the tangential fan impeller according to any one of the first to third aspects, in which each blade is a plurality of blocks in a rotation axis direction. The configuration is such that the relative position of each blade is shifted by δ between adjacent blocks. Here, δ is obtained as the angle at which the amplitude of the composite wave of the NZr components of all blocks in the axial direction is minimized. According to this configuration, it is possible to obtain the same effect of reducing the discrete frequency noise even in the rotation axis direction of the tangential fan impeller.

The tangential fan impeller according to a fifth aspect is the tangential fan impeller according to the fourth aspect, wherein the relative position deviation δ between adjacent blocks is 180 ° ±±. It is calculated in the range of β / 2 °. According to this configuration, since the balance around the rotation axis is adjusted, it is possible to keep the vibration generated when the tangential fan impeller rotates at an allowable level or less.

Further, the air conditioner according to a sixth aspect of the invention adopts a configuration including the tangential fan impeller according to any of the first to fifth aspects as a fan thereof. According to this configuration, the tangential fan impeller can effectively reduce the discrete frequency noise, so that it is possible to provide a quiet air conditioner in which annoying operation noise is significantly reduced.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of an air conditioner including a tangential fan impeller of the present invention.

FIG. 2 is a front view showing the tangential fan impeller.

3A and 3B are diagrams showing the same tangential fan impeller, in which FIG. 3A is a sectional view taken along line AA of FIG. 2 and FIG. 3B is a sectional view taken along line BB of FIG.

FIG. 4 is a diagram showing a pitch interval of each blade of the same tangential fan impeller, in which the horizontal axis represents the blade number in the circumferential direction and the vertical axis represents the blade pitch angle.

FIG. 5 is a vertical cross-sectional view of an indoor unit equipped with a conventional tangential fan impeller.

FIG. 6 is a graph showing frequency characteristics of noise generated by the tangential fan impeller, in which the horizontal axis represents frequency and the vertical axis represents noise.

[Explanation of symbols]

1b ... Stabilizer 7: Indoor heat exchanger 10 ... Indoor unit 20: Outdoor unit 20b: outdoor heat exchanger 20f: Compressor 20g: Outdoor unit controller 30 ... tangential fan impeller, fan 31 ... feather 34, 35 ... Group 33 ... Block CL ... rotation axis

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Toshifumi Kudo             2-1-1 Niihama, Arai-cho, Takasago, Hyogo Prefecture             Takasago Laboratory, Mitsubishi Heavy Industries, Ltd. F-term (reference) 3H031 AA03 BA02                 3H035 CC02 CC06                 3L049 BB07 BC01 BD02

Claims (6)

[Claims] 1. A tangential fan impeller in which a plurality of blades are annularly arranged around a rotation axis to form a cylinder, and the rotation thereof blows the fluid introduced into the outside to the outside. When the number of blades is an even number, they are grouped into an even group having the same number of sheets, and when the number of these blades is an odd number, those except one of them have the same number of sheets. The virtual average pitch angle obtained by dividing 360 ° by the total number of the blades is α, the pitch angle between blades in one of the adjacent groups is β, and the pitch angle in the other group is β. A tangential fan impeller having a pitch deviation angle ε such that β = α + ε and γ = α−ε, where γ is the pitch angle between the blades. 2. The tangential fan impeller according to claim 1, wherein the pitch deviation angle ε is 0 <ε ≦ 0.1α. 3. The tangential fan impeller according to claim 1 or 2, wherein the number of divisions of each group is two. 4. The tangential fan impeller according to claim 1, wherein each blade is divided into a plurality of blocks in the rotation axis direction, and the relative position between adjacent blocks. A tangential fan impeller characterized in that is shifted by δ. 5. The tangential fan impeller according to claim 4, wherein the relative position deviation δ between the adjacent blocks is 18
A tangential fan impeller, which is in the range of 0 ° ± β / 2 °. 6. An indoor unit and an outdoor unit are provided, wherein the indoor unit includes a fan and an indoor heat exchanger arranged around the fan except an air passage for sending air from the fan. A stabilizer disposed between the indoor heat exchanger and the fan to receive drainage generated in the indoor heat exchanger, wherein the outdoor unit has an outdoor heat exchanger and a high temperature and high pressure in the indoor heat exchanger. In the air conditioner provided with the compressor which sends out a gas refrigerant, and the outdoor unit control part which consists of various electric circuit elements, The tangential fan blade in any one of Claim 1 to 5 as said fan. An air conditioner characterized by being equipped with a car.