JP7187140B2 - Tangential fan and air conditioner - Google Patents

Description

The present invention relates to a tangential fan and an air conditioner.

A tangential fan is known as a fan used for an indoor unit of an air conditioner. Unlike axial fans and centrifugal fans, tangential fans are long in the width direction (rotational axis direction) and have a shape in which a plurality of impellers are connected. Each impeller has a plurality of blades arranged in the circumferential direction, and due to interference between each blade and the surroundings, nNZ noise (n: order, N: number of revolutions (frequency), Z: number of blades ) and other peculiar sounds occur.

Since the tangential fan is long in the width direction, if the same frequency sound is generated by rotation, the peak sound that the user feels more uncomfortable will be generated due to amplification, interference, resonance, etc.
In order to suppress the generation of these noises, taking countermeasures by changing the configuration of the tangential fan is being considered.
For example, Patent Literature 1 discloses that arcuate blades are arranged at random pitches in the circumferential direction, and impellers are shifted in the circumferential direction by 1 to 4°.
Further, Patent Document 2 discloses that arc blades are arranged at random pitches in the circumferential direction, and at least one phase difference in the impeller is made different from the other phase differences.
Further, Patent Document 3 discloses that the impellers are alternately shifted and connected.
Further, Patent Document 4 discloses that the displacement of the impeller is represented by the number of blades and the number of impellers.

Japanese Patent No. 2770677 Japanese Patent No. 3460350 Japanese Patent No. 3564462 Japanese Patent No. 4831707

However, in the inventions disclosed in Patent Documents 1 to 4, the deviation of the impeller is within one interval of the blades. There is a problem that the blades at the same position are lined up at intervals. If the blades are arranged at regular intervals in the same position, the frequency of the sound generated by the tangential fan will not be completely out of phase, making it difficult to effectively suppress the noise.
Therefore, in order to complicate the misalignment of the impellers, for example, it is conceivable to prepare different impellers, that is, each impeller with blades arranged at different random pitches, but in this case, the number of parts increases, management and There is a problem that the manufacturing cost increases.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a tangential fan and an air conditioner constructed with one type of impeller and capable of suppressing noise.

In order to solve the above problems, the tangential fan and air conditioner of the present invention employ the following means.
A tangential fan according to a first aspect of the present invention includes a plurality of impellers each having a cylindrical outer shape formed by annularly arranging a plurality of blades around a rotation axis, and connecting a plurality of impellers in the direction of the rotation axis. In the tangential fan that blows out the fluid introduced into the outside, the blades are arranged on the impeller at a random pitch, and the value obtained by dividing 360 ° by the total number of the blades is a virtual average pitch angle, and each of the blades The wheels have the same arrangement of the blades, and the adjacent impellers are within the virtual average pitch angle that is an integral multiple of the virtual average pitch angle and 10 to 50% of the virtual average pitch angle. It is an angle obtained by adding up the shift and the shift, and is connected with a chain shift angle that is an angle that is larger than the virtual average pitch angle.

According to this aspect, a plurality of impellers having a cylindrical outer shape formed by annularly arranging a plurality of blades around the rotation axis are connected in the direction of the rotation axis, and the rotation of the impellers blows out the fluid introduced inside. In a tangential fan, blades are arranged on impellers at random pitches, each impeller has the same blade arrangement, and adjacent impellers are 360° divided by the total number of blades. Since the blades are connected with a chain-ring shift angle larger than the average pitch angle, the arrangement of the blades becomes complicated in the direction of the rotation axis, and almost all the blade positions are different.
As a result, the timing of the blades passing through the same position is different for each impeller, so the frequency of the sound generated by the blades is shifted, and the frequency of the sound generated by the tangential fan becomes complicated. Since the impellers are arranged unevenly, the phases of the generated frequencies are shifted, so that discrete frequency noise having a peak at a single frequency can be suppressed.
In addition, it is possible to make the period of the sound source irregular, and to exhibit the effect of the random pitch that the nNZ sound can be dispersed into a plurality of low peaks.
In addition, since each impeller has the same arrangement of blades, the configuration can be realized with one type of impeller, and the number of parts is not increased, and the management cost and manufacturing cost are not increased.

In the first aspect described above, the chain ring shift angle may be larger than twice the virtual average pitch angle.

According to this aspect, since the chain ring shift angle is larger than twice the value of the virtual average pitch angle, the arrangement of the blades becomes complicated without having periodicity, and the positions of the blades are almost all different. can do.

An air conditioner according to a second aspect of the present invention is an air conditioner that includes an indoor unit and an outdoor unit, and includes the above-described tangential fan in the indoor unit.

According to the present invention, since the impellers are connected with a chain-ring shift angle larger than the virtual average pitch angle, the timing of the blades passing through the same position can be varied.

1 is a perspective view showing a configuration example of an air conditioner according to an embodiment of the present invention; FIG. 1 is a front view showing a tangential fan according to one embodiment of the present invention; FIG. 1 is an exploded perspective view showing a tangential fan according to one embodiment of the present invention; FIG. FIG. 5 is a front view showing a pitch interval when there is no deviation of a tangential fan as a reference example; 5 is a graph showing frequency characteristics of sound when there is no displacement of a tangential fan as a reference example. FIG. 5 is a front view showing a pitch interval of a tangential fan as a reference example when the deviation is within one pitch; FIG. 5 is a graph showing the frequency characteristics of sound in the case of a deviation within one pitch of a tangential fan as a reference example; FIG. FIG. 4 is a representative front view showing the pitch interval of the tangential fan according to one embodiment of the present invention; 5 is a graph showing frequency characteristics of sound of a tangential fan according to one embodiment of the present invention;

An embodiment of a tangential fan and an air conditioner according to the present invention will be described below with reference to the drawings.
An embodiment of the present invention will be described below with reference to FIGS. 1 to 9. FIG.
FIG. 1 shows a configuration example of an air conditioner according to this embodiment.
As shown in FIG. 1, an air conditioner 1 for air conditioning (cooling, heating, and dehumidifying) an indoor space or the like is an apparatus having an outdoor unit 10 and an indoor unit 20 as main components. The outdoor unit 10 and the indoor unit 20 are connected by a refrigerant pipe 50 to form a closed circuit refrigerant flow path. The outdoor unit 10 and the indoor unit 20 are also connected by power supply and control wires (not shown).
Reference numeral 51 in the figure denotes a remote controller for operation, which sets various operating states of the air conditioner 1 .

The outdoor unit 10 includes a substantially rectangular parallelepiped housing 11, which includes a compressor 12 for compressing the refrigerant, an outdoor heat exchanger 13 for exchanging heat between the refrigerant and outdoor air, and an outdoor fan 14 for promoting heat exchange between the refrigerant in the outdoor heat exchanger 13 and the outdoor air. A four-way valve, an electronic expansion valve, a control unit, and the like (not shown) are also arranged inside the housing 11 .
The outdoor heat exchanger 13 is a heat exchanger that functions as a condenser during cooling operation and as an evaporator during heating operation by operating a four-way valve to switch the circulation direction of the refrigerant.

The indoor unit 20 includes a housing 21 having a laterally long substantially rectangular parallelepiped shape. The housing 21 includes a base body 22, a front cover 23 attached to the base body 22 so as to cover the front portion of the base body 22 from the top, bottom, left, and right, and the front when the housing is installed on a wall. It is generally constituted by an attached front panel 24 .

The indoor unit 20 includes an intake grille (intake port) 25 provided on a front cover 23 for taking in pre-air-conditioned air (hereinafter referred to as "fresh air") from the room, and fresh air taken in from the intake grille 25. An indoor heat exchanger 26 provided for cooling or heating the air, and the air heat-exchanged by the indoor heat exchanger 26 (hereinafter referred to as "conditioned air") provided on the front panel 24 for returning to the room A tangential fan 28 is provided as a main component for taking in fresh air from the air outlet 27 and the intake grille 25 and for blowing conditioned air from the air outlet 27 into the room.

The indoor heat exchanger 26 and the tangential fan 28 are supported by the base body 22 inside the housing 21 .
Reference numeral 29 in the drawing denotes a filter, which is provided to remove impurities such as dust and dirt contained in the fresh air that passes through the intake grille 25 and is led to the indoor heat exchanger 26 . The air outlet 27 is provided with a louver and a flap (not shown) in order to adjust the blowing direction of the conditioned air.
The indoor heat exchanger 26 is a heat exchanger that functions as an evaporator during cooling operation and as a condenser during heating operation, depending on the circulation direction of the refrigerant.

In the indoor unit 20 having the configuration described above, the tangential fan 28 driven by a motor is rotatably supported by the base body 22 forming the housing 21 of the indoor unit 20 . The tangential fan 28 is arranged in an air flow path formed in the base body 22 so as to connect between the intake grille 25 and the air outlet 27 .

FIG. 2 is a front view showing a tangential fan provided in the indoor unit of this embodiment.
FIG. 3 is an exploded perspective view of part of the tangential fan provided in the indoor unit of this embodiment.

As shown in FIGS. 2 and 3, the tangential fan 28 of the present embodiment has, for example, 35 (plurality of blades) blades (blades) 31 annularly arranged around the rotation axis CL to form a tubular blade. A plurality of wheels 30 are connected in the direction of the rotation axis CL through intervening plates 32, and the rotation of the wheels 30 blows out the fluid introduced inside.

The blades 31 of one impeller 30 are arranged at random pitches in which pitches between adjacent blades 31 are unequal. In this embodiment, the impellers 30 are all identical, that is, the blades 31 of each impeller 30 are all arranged at the same random pitch.
Here, the average angle of the pitch interval of each blade 31 is a value obtained by dividing 360° by the total number of blades 31 (35 in the case of the representative of this embodiment) (360°/35=10.3°). , which is assumed to be the virtual average pitch angle.

Next, the relationship between the connection angle of each impeller 30 in the tangential fan 28 and the noise generated will be described.
FIG. 4 is a front view showing a pitch interval when there is no displacement of a tangential fan as a reference example.
FIG. 4 shows the arrangement and spacing of some of the blades 31 in the four impellers 30, 30a, 30b, 30c and 30d. Each impeller 30 rotates, and each blade 31 moves from top to bottom in the drawing.
In the case of FIG. 4, the impellers 30 with random pitch are not shifted in the moving direction (circumferential direction) of the blades 31, and the blades 31 adjacent to each other via the intervening plates 32 between the impellers 30 are all in the same position. are placed.
In this case, the blades 31 passing through the reference position represented by the dashed line all pass at the same timing as represented by the thick line.
In the following description, when the impellers 30 are to be distinguished, one of a to d is added to the end of the reference numerals, and when the impellers 30 are not to be distinguished, a to d are omitted.

FIG. 5 is a graph showing frequency characteristics of sound when there is no deviation of the tangential fan as a reference example.
In FIG. 5, the vertical axis indicates the sound pressure level (noise level at each frequency) Lp, and the horizontal axis indicates the sound frequency Hz.
The tangential fan 28 is elongated in the width direction, and the blades 31 are arranged in a ring. Therefore, due to interference with the surroundings, a peculiar sound such as an nNZ sound having a peak at a single frequency is generated (N: tangential fan). number of rotations of the xential fan 28, Z: number of blades 31, n: order).
As shown in the graph, when there is no deviation between the impellers 30, nNZ noise is generated even with a random pitch.

FIG. 6 is a front view showing a pitch interval of a tangential fan as a reference example when the deviation is within one pitch.
The arrangement of some of the blades 31 in the four impellers 30a, 30b, 30c and 30d is represented by horizontal bars and their intervals. Each impeller 30 rotates, and each blade 31 moves from top to bottom in the drawing.
The impeller 30 is connected to other adjacent impellers 30 with a constant gap of a virtual average pitch angle of 10.3° or less. One pitch of the tangential fan 28 can be said to be the interval between the blades 31 represented by the virtual average pitch angle.
In this case, since the blades 31 corresponding to the same position of each impeller 30 are shifted at regular intervals, the blades 31 passing through the reference position represented by the dashed line pass at a constant timing (cycle) as represented by the thick line. do.

FIG. 7 is a graph showing frequency characteristics of sound in a tangential fan as a reference example when the deviation is within one pitch.
In FIG. 7, the vertical axis indicates the sound pressure level (noise level at each frequency) Lp, and the horizontal axis indicates the sound frequency Hz.
As shown in the graph, when the deviation between the impellers 30 is within one pitch, the pitch deviation causes a phase difference with the waveform of the nNZ component in the time axis direction, which cancels each other and attenuates. However, although the sound pressure level of the nNZ sound is lower than when there is no deviation, the peak of the nNZ sound appears.

Therefore, in this embodiment, the displacement between the impellers 30 is set to be larger than one pitch.
FIG. 8 graphically illustrates the pitch interval of a tangential fan according to an embodiment of the present invention (representative view of deviation within 1 pitch+1 pitch).
The arrangement of some of the blades 31 in the four impellers 30a, 30b, 30c and 30d is represented by horizontal bars and their intervals. Each impeller 30 rotates, and each blade 31 moves from top to bottom in the drawing.
Using one impeller 30 as a reference, adjacent impellers 30 are rotated one pitch at a time and connected with a deviation of one pitch or less as in the conventional case. Here, the reason for providing a conventional deviation of less than one pitch is to avoid the fact that the blades 31 of any two impellers 30 may all be arranged at the same position if there is only a deviation of one pitch. is. The deviation within one pitch is 10% to 50% of the virtual average pitch angle in this embodiment.

A link shift angle θ between an impeller 30 and another adjacent impeller 30 is expressed by the following equation (1).
[Number 1]
θ=360°/35×(360°/35)×(0.1 to 0.5) (1)

In formula (1), "360°/35" is a deviation of 1 pitch, that is, a virtual average pitch angle, and "(360°/35) × (0.1 to 0.5)" is a deviation within 1 pitch. .

The impeller 30 is connected to other adjacent impellers 30 with a shift due to the link shift angle θ.
In this case, the blades 31 corresponding to the same position of each impeller 30 are connected at an interval of one pitch or more because each impeller 30 is connected with a chain-ring shift angle θ larger than the virtual average pitch angle. out of alignment. Therefore, the blades 31 passing through the reference position represented by the dashed line are adjacent to the blades 31 represented by the thick line of the impeller 30a, such as the blades 31 represented by the dashed-dotted lines of the impellers 30b, 30c and 30d. , the interval will be random, and it will pass at different times.
Also, as with the blades 31 of the impeller 30d indicated by the thick dashed line, the blades 31 of the distant impeller 30 may pass the reference position first instead of the blades 31 of the adjacent impeller 30.

By connecting the impellers 30 with the chain-ring shift angle θ in this way, when the impellers 30 are compared at the same position as the above-described reference position, the blades 31 are arranged at random pitches in the circumferential direction. , the positions of the blades 31 are all different.
As a result, the timing of the blades 31 passing through the same position is different for each impeller 30, so that the frequency of the generated sound is shifted.

FIG. 9 is a graph showing frequency characteristics of sound of a tangential fan according to one embodiment of the present invention.
In FIG. 9, the vertical axis indicates the sound pressure level (noise level at each frequency) Lp, and the horizontal axis indicates the sound frequency Hz.
As shown in the graph, when the displacement between the impellers 30 is set to a chain-ring displacement angle larger than 1 pitch, the positions of the blades 31 of the adjacent impellers 30 become complicated and pass through the same position. Blade 31 timing is complicated and out of frequency. Therefore, the frequency shifts further than when the shift is within one pitch, the peak of the nNZ sound is lowered, and as a result, noise can be suppressed.

Further, the chain ring shift angle may be set to a different value as long as it is larger than one pitch. For example, it may be a value obtained by rotating adjacent impellers 30 not by one pitch but by 30% in the circumferential direction.
With one impeller 30 as a reference, adjacent impellers 30 are rotated by 30% in the circumferential direction, and further connected with a deviation of less than 1 pitch as in the prior art. Here, the deviation within 1 pitch as in the conventional case is to avoid the fact that the blades 31 of any two impellers 30 may be arranged at the same position only at 30% rotation. is. The deviation within one pitch is 10% to 50% of the virtual average pitch angle in this embodiment.

The link shift angle, which is the shift angle of each impeller 30, is represented by the following formula (2) (30% rotation in the circumferential direction + shift within 1 pitch).
[Number 2]
±(360°×0.3)+(360°/35)×(0.1-0.5) (2)

In the formula (2), “360°×0.3” is the 30% rotation angle in the circumferential direction, “360°/35” is the virtual average pitch angle, and “(360°/35)×(0.1 ~0.5)” is a deviation within one pitch.

FIG. 3 shows a schematic diagram of a case where adjacent impellers 30 are rotated by 30% in the circumferential direction and connected with a deviation of one pitch or less.
The impellers 30a, 30b, and 30c have blades 31 arranged at random pitches, and the impellers 30a, 30b, and 30c have the same blade 31 arrangement. When one blade 31a of impeller 30a is selected, 31a arranged at the same position can be selected also in impellers 30b and 30c.
As shown in FIG. 3, when the blade 31a of the impeller 30a is used as a reference, the blade 31a of the adjacent impeller 30b is rotated 30% in the circumferential direction and moved to a position with a deviation of less than one pitch. In this state, the impeller 30a and the impeller 30b are connected. Similarly, with the blades 31a of the impeller 30b as a reference, the blades 31a of the adjacent impeller 30c are rotated 30% in the circumferential direction and moved to a position with a deviation of one pitch or less. and the impeller 30c are connected.

<Modification 1>
In Modification 1, the chain-ring shifting angle is two pitches or more.
In this modification 1, one impeller 30 is used as a reference, and adjacent impellers 30 are rotated or reversely rotated by n times the virtual average pitch angle in the circumferential direction (n = 2, 3, ... 34, n is an integer), and are connected with a deviation of less than one pitch as in the conventional case. The deviation within one pitch is 10 to 50% of the virtual average pitch angle in this embodiment.

A link shift angle, which is the shift angle of each impeller 30, is expressed by the following equation (3).
[Number 3]
±(360°/35)×n+(360°/35)×(0.1 to 0.5) (3)

In equation (3), "360°/35" is the virtual average pitch angle, and "(360°/35)×(0.1 to 0.5)" is the deviation within one pitch. Also, n is an integer from 2 to 34.

By making it possible to select two or more pitches for the chain-ring shift angle and n, an appropriate combination can be set with respect to the type of random pitch and the combination of units on which the impellers 30 are mounted.
In addition, since it is possible to determine the chain shift angle for the frequency of the sound that is desired to be reduced among the generated noise, it is possible to connect the impellers 30 according to the characteristics of the configuration of each impeller 30 and the type of random pitch. can be As for how to connect the impellers 30, that is, how to set each chain-ring shift angle, a test may be conducted to determine a value that can most effectively reduce noise.

<Modification 2>
In Modified Example 2, the link shift angle is set according to the number of blades 31 .
In Modification 2, one impeller 30 is used as a reference, and adjacent impellers 30 are rotated or reversely rotated by n times the virtual average pitch angle in the circumferential direction (n=1, 2, . . . z- 1 and n are integers), and are connected with a deviation of less than 1 pitch as in the conventional case. The deviation within one pitch is 10 to 50% of the virtual average pitch angle in this embodiment.

A link shift angle, which is the shift angle of each impeller 30, is expressed by the following equation (4).
[Number 4]
±(360°/z)×(n)+(360°/z)×(0.1 to 0.5) (4)

In the formula (4), z is the number of blades 31 arranged in the impeller 30, "360 ° / z" is the virtual average pitch angle, "(360 ° / z) × (0.1 to 0.5)" is a deviation within one pitch. Also, n is an integer from 1 to (z−1).

By making it possible to select 1 or more pitches for the chain shift angle and n, and by making it possible to select the number of blades 31, it is possible to select the type of random pitch, the combination of units equipped with the impeller 30, and the number of blades. to set the appropriate combination.
In addition, since it is possible to determine the chain shift angle for the frequency of the sound that is desired to be reduced among the generated noise, it is possible to connect the impellers 30 according to the characteristics of the configuration of each impeller 30 and the type of random pitch. can be As for how to connect the impellers 30, that is, how to set each chain-ring shift angle, a test may be conducted to determine a value that can most effectively reduce noise.

As described above, according to the tangential fan and the air conditioner according to the present embodiment, the following effects are achieved.
A tangential fan in which a plurality of impellers 30 having a cylindrical outer shape formed by annularly arranging a plurality of blades 31 around a rotation axis are connected in the direction of the rotation axis, and the fluid introduced inside is blown out by the rotation thereof. 28, the blades 31 are arranged on the impellers 30 at a random pitch, each impeller 30 has the same arrangement of the blades 31, and the adjacent impellers 30 are 360° divided by the total number of blades 31. , the arrangement of the blades 31 becomes complicated in the rotation axis direction and the positions of the blades 31 are almost all different.
As a result, the timing of the blades 31 passing through the same position is different for each impeller 30, so the frequency of the sound generated by the blades 31 is shifted, and the frequency of the sound generated by the tangential fan becomes complicated. When the impellers 30 are arranged unevenly, the phases of the generated frequencies are shifted, so that discrete frequency noise having a peak at a single frequency can be suppressed.
In addition, it is possible to make the period of the sound source irregular, and to exhibit the effect of the random pitch that the nNZ sound can be dispersed into a plurality of low peaks.
In addition, since the arrangement of the blades 31 is the same for each impeller 30, the configuration can be realized with one type of impeller 30, and the number of parts is not increased, and the management cost and manufacturing cost are not increased. .

Further, according to the present embodiment, since the chain ring shift angle is larger than twice the value of the virtual average pitch angle, the arrangement of the blades 31 becomes complicated without periodicity, and the position of the blades 31 is almost All can be in different positions.

An embodiment of the present invention has been described in detail above with reference to the drawings, but the specific configuration is not limited to this embodiment. Although it is provided in the indoor unit 20 of the conditioner 1, it may be provided in other air-operated equipment such as a blower.

1 air conditioner 20 indoor unit 28 tangential fan 30 impeller 31 blade

Claims (3)

A tangential fan in which a plurality of impellers having a cylindrical outer shape with a plurality of blades arranged in a ring around a rotation axis are connected in the direction of the rotation axis, and the fluid introduced inside is blown out by the rotation thereof,
The blades are arranged on the impeller at a random pitch, and the value obtained by dividing 360 ° by the total number of the blades is a virtual average pitch angle,
Each of the impellers has the same arrangement of the blades,
The adjacent impellers have an angle obtained by adding an angle that is an integral multiple of the virtual average pitch angle and a deviation within the virtual average pitch angle that is 10 to 50% of the virtual average pitch angle, and A tangential fan that is connected with a chain-ring shift angle that is larger than the virtual average pitch angle. 2. The tangential fan according to claim 1 , wherein the chain-ring shift angle is larger than twice the virtual average pitch angle. An air conditioner comprising an indoor unit and an outdoor unit,
An air conditioner comprising the tangential fan according to claim 1 or 2 in the indoor unit.

Images