JPH08200283A - Cross-flow fan and air conditioner provided with it - Google Patents

Abstract

PURPOSE: To reduce a rotational sound of low frequency according to rotation by tilting an individual blade at a prescribed angle in the same direction relating to an axial direction parallel line from one end disk leading to the other end disk of a plurality of the support disks, also arranging the blade by a random pitch in the peripheral direction. CONSTITUTION: A cross-flow fan 1 of an air conditioner has blades 2... which are a single sheet blade inserted through each support disk 3 from one end to the other end of a plurality of the support disks 3 arranged with an almost equal space in an axial direction of the fan. Each blade 2 is uniformly formed with a tilt, so-called skew, of advancing a drive side (motor 5 side) rather than a driven side (shaft 4 side) by a prescribed amount in a rotational direction U. The blade 2 is formed in a sectional shape bent to be tilted forward to a side of the rotational direction U, to arrange the many blades 2 in a peripheral direction aside the periphery of the support disk 3 by random pitches P1 , P2 , P3 , P4 ...P34 . This random degree δ (maximum pitch/minimum pitch) is selected to a prescribed value in a 1.2 to 1.5 range.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cross-flow fan and an air conditioner equipped with the same, and particularly to reduce the rotational noise of the blade body and the turbulent noise caused by the flow due to the blade arrangement (phase) in the axial direction. , A rotary primary sound related to the blade pitch, and a secondary rotary sound due to the position of the heat exchanger, which is convenient and has a low noise level and good audibility, can be obtained, and the size of the air conditioner can be reduced or reduced. The present invention relates to a once-through fan having a structure that contributes to resource and energy saving, and an air conditioner including the same.

[0002]

2. Description of the Related Art In a conventional cross-flow fan, as a method of reducing the rotation noise, for example, as described in Japanese Utility Model Laid-Open No. 4-79991, the chord length or blade pitch of the blades is intentionally set in the blade row direction (circumferential direction). A structure in which a plurality of impellers are connected randomly is known. Also, for example, the actual exploitation 52
As described in Japanese Patent No. 13232312, it has been known that the blade is a single blade extending from the left end to the right end of the supporting disk and is inclined at a predetermined angle with respect to the axial direction, and the blade row has an equal pitch. The blade cross section is curved in the rotational direction with the same curvature from the inner peripheral side to the outer peripheral side of the blade row. In an air conditioner using this type of cross-flow fan, the heat exchanger is arranged as far as possible from the cross-flow fan in order to prevent noise from being generated due to the influence of the heat exchanger.

[0003]

In the former case of the above-mentioned prior art, in the case where the chord length of the blade is random, it is necessary to increase the ability by providing a blade having a longer chord length for the shorter chord length. However, there was a problem that the outer diameter of the fan would be correspondingly large.

FIG. 11 is a front view of a conventional cross-flow fan, FIG. 12 is a sectional view taken along the line BB of FIG. 11, and FIG.
FIG. 8 is a vertical cross-sectional view of a conventional air conditioner including the cross-flow fan of FIG. The cross-flow fan 31 shown in FIG. 11 has blades 3 perpendicular to the disk.
Small impeller 3 with a small width (axial length) supporting 2
One air blower is configured by connecting a plurality of 1a. As shown in FIG. 12, in the case where the blade pitch in the blade row direction is random, the phase of the blades 32 is abruptly deviated at the connecting portion, that is, the supporting disk 33, and is related to the number of small impellers 31a connected. Low-frequency rotating noise is generated. Also, regarding the flow of wind, there is a problem in that interference occurs due to the difference in speed between the left and right sides of the connecting portion, the fluid noise increases, and the air volume decreases.

A large number of combinations can be considered for randomizing the pitches P ₀₁ , P ₀₂ , ... In the blade row direction, and depending on the degree of randomness (here, the maximum pitch / minimum pitch ratio will be referred to), There was a lack of awareness about the problem that the rotating sound was unintentionally high. In addition to this, if a blade 32 with a small capacity (a part with a small string or a narrow pitch) comes to the suction side and at the same time a blade 32 with a small capacity also comes to the discharge side, the air volume decreases, which is the opposite of this. In some cases, the air volume will increase. Therefore, there is a problem in that the amount of ventilation is changed and vibrations are generated, and at the same time, a rotation sound that is an integral multiple of the vibration frequency (or rotation speed) of the blade body is generated.

The latter through-flow blower of the above-mentioned prior art is a single blade extending from the left end to the right end of the supporting disk, but with respect to the same blade, there is a phase shift in the axial direction (stepwise generally small blades. (Each vehicle has the same phase), but because the blade rows have the same pitch and the dimensions between blades are all the same, the interference between the blades and fixed casing and the flow form between the blades are the same. However, there is a problem that the generation of the rotating primary sound due to the number of blades cannot be sufficiently eliminated.

The former and latter blades 32 have a substantially crescent shape in which the inner peripheral side and the outer peripheral side are symmetrical, with a bulge side and a concave side each having a circular curvature from the inner peripheral side to the outer peripheral side of the blade row. It was made of a resin or a metal plate of the same thickness bent in the rotational direction with concentric curvature. Therefore, as shown in FIG. 13, when it is attempted to arrange the heat exchanger 33 close to the cross-flow fan 31 in order to make the air conditioner compact, the blade tips sensitively affect the inflow of wind and the heat exchange is performed. Due to the difference in the flow velocity distribution in the vicinity of the fin 33a of the vessel 33 and the pipe 33b, the fluctuation of the inflow situation into the rotatively moving blade 32 becomes severe, and there is a problem that a rotational secondary sound is generated from the blade 32 portion. , There was a lack of consideration to prevent this.

The present invention has been made in order to solve the above-mentioned problems of the prior art, and the first object thereof is to reduce the discontinuous fluid noise near the supporting disk of the blade and to reduce the air flow fluctuation. This reduces the low-frequency rotation noise that accompanies the rotation of the impeller, and mainly reduces the rotational primary sound related to the number of blades with high frequency. It is to provide a low-flow once-through fan with good hearing and low noise. A second object of the present invention is to reduce the secondary noise generated in the downstream of the heat exchanger mainly by using the cross-flow fan to reduce the noise and compact the product. Accordingly, it is to provide an air conditioner that can contribute to resource saving or energy saving.

[0009]

In order to achieve the above-mentioned first object, the structure of the first invention relating to the cross-flow fan of the present invention is the outer circumference of a plurality of supporting discs arranged in the axial direction at predetermined intervals. In a cross-flow fan in which a large number of blades are arranged in the circumferential direction closer to each other, the individual blades are arranged with respect to an axial parallel line extending from a disc at one end of the plurality of supporting discs to a disc at the other end. And inclining in the same direction at a predetermined angle, the multiple wings are
It is arranged at a random pitch in the circumferential direction. More specifically, each blade has a tip end on the outer peripheral side in the cross-sectional shape of the blade inclined in the rotational direction with a curvature slightly larger than the curvature inside thereof.

Further, in order to achieve the above first object,
The structure of the second invention relating to the cross-flow fan of the present invention is such that a plurality of integrally-formed small impellers each having a plurality of blades arranged in the circumferential direction are axially connected to one surface near the outer circumference of the supporting disk. In the cross-flow fan, the plurality of blades are arranged at a predetermined angle with respect to an axial parallel line extending from a disc at one end of the plurality of support discs to a disc at the other end through the support discs. It is straight and inclined in the same direction. And many wings
The blades are arranged at random pitches in the circumferential direction, and a large number of blades are obtained by inclining the outer circumferential end of the blades in the cross-sectional shape in the rotational direction with a curvature slightly stronger than the inner curvature.

The inclination of the blade with respect to the parallel line in the axial direction can be achieved by performing it for each impeller even if a plurality of impellers are connected. In the first and second aspects of the invention, the blade inclination angle (skew
Angle) of 1 to 4.5 degrees, and the arrangement of the blades in the circumferential direction is a random degree (maximum pitch / minimum pitch) of 1.2 to 1.5.
It can be achieved highly effectively by setting to.

The cross-flow fan can be easily manufactured by twisting the impeller after the work of inserting the blade into the supporting disk and fixing the blade by caulking or welding the supporting disk.
Alternatively, in the case of a plural-connection type fan made of resin, it can be easily manufactured by making the blade-to-blade forming die a slight rotary slide type.

In order to achieve the above second object,
The structure of the air conditioner according to the present invention uses one of the cross-flow fans described above, and has a cross-sectional structure that surrounds the cross-flow fan by having at least two bent portions on the inlet opening side of the cross-flow fan. A cross fin pipe type heat exchanger is provided, and a suction opening is provided at a position corresponding to the heat exchanger in the casing.

[0014]

The function of each of the above technical means is as follows.
That is, the blade is inclined from the left end to the right end of the supporting disk by a predetermined angle with respect to the parallel line in the axial direction with a single blade, and in the case of a plurality of connected impellers, each impeller is By tilting the blades by a predetermined angle and arranging them linearly through the supporting discs, there is no stepped phase deviation of the blades for each supporting disc portion, and smooth rotation can be obtained. Therefore, a smooth flow with little change in flow velocity and turbulence at the supporting disk is obtained, and low-frequency vibration (rotation speed per second and its integral multiple frequency) accompanying rotation of the blade body and its rotation are obtained. You can eliminate the sound.

Further, by randomly arranging the blades in the circumferential direction (blade pitch), it is possible to eliminate the periodicity of blade movement and to disperse high-frequency rotation noise related to the number of blades, and also between blades. Due to the difference in size, the generation frequency of the fluid sound is dispersed to make it easier to hear, and the noise level can be lowered. Furthermore, the tip of the blade section (outer side of the blade row)
By arranging a small amount of
It softens the start of sudden entry into the wing from the inflow end of the sing, and reduces the generation of rotational secondary sound, mainly accompanying rotational primary sound, and at the same time improves the strength of the wing.

In addition to the above-mentioned operation, the air conditioner using the cross-flow fan according to the present invention has a non-uniform velocity distribution in the wake of the heat exchanger arranged in the vicinity of the cross-flow fan. The change in inflow can be reduced, and in particular, the secondary sound due to the interference between the blade and the heat exchanger can be reduced. Therefore, the audibility of noise can be improved and the noise level (overall value) can be reduced. As an air conditioner structure, the heat exchanger is arranged in close proximity so as to surround the once-through fan and can be configured compactly, and since it can have a large heat transfer area, the heat exchange capacity is improved, The amount can be saved as resources and energy (power).

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, each embodiment of the present invention will be described with reference to FIGS.
It will be specifically described with reference to. [Embodiment 1-1] First, FIG. 1 is a front view of a cross-flow fan according to an embodiment of the first invention, FIG. 2 is a sectional view of the impeller of FIG. , FIG. 1 and FIG.
6 is a vertical cross-sectional view of an air conditioner including the cross-flow fan shown in FIG.

The blades 2 shown in FIGS. 1 and 2 extend from one end to the other end of a plurality of supporting discs 3 arranged at substantially equal intervals in the axial direction of the cross-flow fan 1, that is, from the left end to the right end in FIG. One blade penetrates each supporting disk 3. Each blade 2 is evenly arranged on the drive side (motor 5) rather than the driven side (shaft 4 side).
(Side) is moved by a predetermined amount in the direction U of rotation, a so-called inclination,
It forms a skew. The blade 2 has a cross section in which a material having the same thickness is plastically worked into a circular arc on the side in the direction of rotation U indicated by an arrow and is bent and bent forward. As for the amount of the predetermined inclination angle, the inclination angle θ of the blade with respect to the parallel line is assumed to be 1 ° to 4.5 ° in the development view (assuming the parallel line to the axial direction, the axial parallel line is the base, and the axial direction is the axial direction). It is set to a predetermined value within the range of the tan angle with the plane development distance shifted along the outermost periphery, and this type of fan corresponds to about 1.5 pitch to about 6.0 pitch). is there.

Further, a large number of blades 2 are arranged at a random pitch P ₁ , P ₂ , P ₃ , P ₄ , ... P ₃₄ in the circumferential direction near the outer circumference of the supporting disk 3, and the randomness δ (maximum pitch / The minimum pitch) is selected to be a predetermined value within the range of 1.2 to 1.5 so that there is no portion where the pitch arrangement order is the same as much as possible. Reference numeral 6 denotes a front casing, which is slightly separated from the cross-flow fan 1 and surrounds the periphery by about 10% as shown in FIG. 3, and the end delayed in the rotational direction U is formed as a front edge 6a for the inlet.
A narrow parallel distance is formed with the outer periphery of the cross-flow fan 1 in the axial direction, and the end that is early in the other rotation direction U is used as an outlet tongue portion 6b, and the distance with the cross-flow fan 1 is made larger than the front edge 6a. There is. The back side thereof also serves as the first dew tray 6c.

Further, 7 is a rear casing, which is slightly separated from the cross-flow fan 1 with a position shifted by about 180 ° from the front edge 6a as a winding start point 7a, and is gently swirled around the cross-flow fan 1 in the rotational direction U. The winding end 7b is formed by gradually winding away the extra 90 °. The leading edge 6a and the winding start point 7
The inlet opening 9 is defined between a and a, and the outlet opening 10 is defined between the tongue 6b and the winding end 7b. The front casing 6 functions as a pressure partition between the inlet opening 9 and the outlet opening 10, and the rear casing 7 separates the flow from the outside air to improve the blowing efficiency and also serves as a guide for the flow direction. To fulfill.

Reference numeral 11 is an internal vortex generated by the flow passing through the blade portion, 12 is a free vortex that can be formed in the backflow of the leading edge 6a, and 13 is a cross-fin pipe type heat exchanger,
At the inlet opening 9, the cross section thereof is bent at three places, and the cross-flow fan 1 is disposed so as to surround it. Reference numeral 16 denotes an outer box, and 16a denotes suction openings on the front surface, the upper surface, and the upper rear surface, which are provided at positions corresponding to the front surface of the heat exchanger 13. 1
Reference numeral 7 is a pipe for transporting the refrigerant, 18 is an engaging portion for installation, 19 is an installation plate, and 20 is a second dew tray.

The cross-flow fan 1 constructed as described above is rotated between the casings 6 and 7 to generate an internal vortex 11 in the impeller near the front casing 6 by centrifugal force, and the wind is generated. It is sucked from the wide inlet opening 9 of the ventilation passage, penetrates the inside of the impeller, and has an internal vortex 11 at a center of about 90 °.
It is deflected as described above and discharged from the outlet opening 10 having a narrow width of the ventilation passage.

Here, when the blade 2 moves near the front casing 6, the flow velocity between the front casing 6 and the blade 2 moves toward the inlet opening 9 faster than that of the blade 2, and between the blades. Flows in a situation where the flow is stagnant and the relative velocity with the blades 2 is equal to zero, and as soon as the blades 2 reach the leading edge 6a, they rapidly flow into the impeller from between the blades. Conventionally, a rapid inflow from the leading edge 6a that occurs at the same time as this flow change, and a free vortex 12 generated from the leading edge 6a interferes with the blade 2 when flowing into the blade 2 and causes a rotating primary sound and a high-frequency turbulent sound. Was occurring.

However, in the structure of this cross-flow fan, since the blades 2 extend from the left end to the right end of the supporting disk 3 and all the blades are inclined in the same direction at a predetermined angle with respect to the parallel lines in the axial direction, The blade phase shift for 6a goes from the left end to the right end,
The steps are performed continuously little by little, and there is no phase difference between the blades 2 on the left and right with the support disk 3 as a boundary. Therefore, the left and right velocities are substantially the same, interference is eliminated, and the inflow to the blade 2 can be made smooth over the entire width. For this reason, the fluctuation of the flow is reduced as well as the reduction of the primary sound of rotation, and the low-frequency vibration of the rotation of the blade body (a frequency that is an integral multiple of the number of rotations per second) and the high-frequency waves that have been generated due to the conventional interference. Fluid noise (frequency higher than the primary rotation sound) can also be reduced.

Actually, as shown in FIG. 3 having a cooling capacity of 2.5 kW, the cross-fin pipe type heat exchanger 13 is formed by bending the cross section at three points to increase the heat transfer area. Using an air conditioner prototype that is compactly arranged to surround the cross-flow fan 1, an outer diameter of 90 mm, axial length of 634 mm, number of blades of 34, uniform pitch blade, cross-flow double arc blade made of resin The fan 1 was incorporated and operated at 1242 rpm, and noise analysis was performed at a 10 Hz pitch.

FIG. 7 shows the cross-flow fan 1 of the embodiment of FIG.
It is a diagram of the noise analysis result which shows the effect of what made the blade 2 the continuous skew. FIG. 7 shows the frequency (Hz) on the horizontal axis and the sound pressure level (dB) on the vertical axis, showing the data of the continuous skew fan of this embodiment with a broken line and the data of the conventional stepwise phase fan with a solid line. Is.

As shown in FIG. 7, this embodiment is compared with a conventional multi-connection fan made of resin (see FIG. 11) having a stepwise phase of half pitch of blades 32 for each supporting disk. When the blade 2 has a continuous inclination angle θ of 2.6 °, an integral multiple of low frequency 1N related to the rotation speed N per second as the blade body
(20.7Hz) ~ 20N (414Hz) rotating sound is 3
dB to 9 dB can be reduced, and the rotating primary sound 1NZ (704H
As for z), what was 30 dB was 6 dB up to 24 dB.
B could be reduced, and the noise over-all value was 42 dB from 41 dB to 1 dB. Also, the effect of increasing the air volume by 4% was confirmed. Comparing the actual effects with the same air volume, it is possible to reduce the over-all value by 2 dB.

Although not shown, the inclination angle θ is 1
If it is less than °, the effect cannot be confirmed, and the tilt angle θ is 4.
If it exceeds 5 °, there will be a part where the outer diameter is small at the strained part where the plastic working of the blade is impossible (for example, the part where the blade cross-section inclination is excessive or insufficient) and the part where the supporting disc is removed, and the rotating primary sound 1NZ It was found that the air volume decreased as the temperature increased.

In the present invention, the circumferential arrangement of the blades 2 is
Randomness δ (maximum pitch / minimum pitch) 1.2 to
Since it is characterized in that the blades are arranged at a predetermined pitch in the range of 1.5, there is no periodicity in the passage of the blade 2 with respect to the front edge 6a of the front casing 6, and the rotating primary sound 1NZ relating to the number of blades is obtained. The blade pitch can be reduced and the blade pitches P ₁ , P ₂ , P ₃ , P ₄ , ... P can be reduced.
_{Since the 34} dimensions are different and dispersed, the fluid sound can be dispersed in a wide frequency band, and the sound pressure level can be made low to make it easy to hear.

According to the experiment, the air conditioner prototype shown in FIG. 3 was used as described above, and the outer diameter was 90 mm and the axial length was 634.
mm, the number of blades is 34, the inclination angle θ of the blades 15 is 2.6 °, and a resin cross-flow fan with a double circular arc blade in cross section is incorporated, and 12 per minute
It was performed at 42 rotations, and noise analysis was performed at a 10 Hz pitch. As a result, the randomness δ of the blade arrangement is 1.43.
The ones were the best. FIG. 8 is a diagram of a noise analysis result showing an effect of the cross-flow fan of the embodiment of FIG. 1 in which a double-arc blade has a random pitch. FIG. 8 shows the frequency (Hz) on the horizontal axis and the sound pressure level (dB) on the vertical axis, and shows the data of the random pitch blade fan with a solid line and the data of the equal pitch blade fan with a broken line.

As shown by the solid line in FIG. 8, the rotational primary sound 1NZ related to the number of blades has 24 blades with a uniform pitch.
It was reduced by 19 dB to 5 dB compared to dB, and the secondary secondary sound 2NZ was reduced from 26 dB to 20 with the decrease in the primary sound.
A 6 dB reduction in dB was obtained. The over-the-noise value of 41dB was changed from 41dB to 39.5dB,
The air volume is almost unchanged, and the fluctuation is small.
A reduction effect of 5 dB was confirmed. In this case, the high frequency fluid sound of 900 Hz or higher was slightly increased due to the influence of a narrow portion between the wings due to the randomization, but according to the actual hearing feeling, the effect of making the remaining rotational sound secondary sound 2NZ less noticeable. I was able to confirm that

Although not shown in the figure, when the randomness δ is less than 1.2, the effect of reducing the rotating noise is compared with that in the blade array having a uniform pitch, and the noise is overwhelmed. -The effect is less than 0.5 dB in terms of the Rule value. Randomness δ is 1.
When the number exceeds 5, the low-frequency rotating primary sound 1NZ of the vane body begins to be generated, and the secondary sound 2NZ also appears due to the influence of the heat exchanger wake. On the other hand, since there is a narrow part between the wings, a sound with a higher frequency is emitted from the vicinity of the secondary sound 2NZ, and due to the wide part between the wings, low-frequency vibration is generated in the blade body itself. It was confirmed that the over-all value of noise was higher than that of the blades with the same pitch. Even if the best randomness δ is 1.43, the rotating secondary sound 2NZ still remains in the spectrum as a peak, but this is due to the heat exchanger 13
However, it can be solved by the blade shape described later.

[Embodiment 1-2] FIG. 4 is an enlarged cross-sectional view of a blade of a cross-flow fan according to another embodiment of the first invention, FIG.
(A) is a velocity triangle for explaining the inflow situation in the portion where the draft resistance to the blade in FIG. 4 is small, and FIG. 5 (b) is the velocity triangle for explaining the inflow situation in the portion where the draft resistance to the blade in FIG. 4 is large. Speed triangle, FIG. 9 shows the flow-through fan of the embodiment of FIG.
It is a diagram of the noise analysis result which shows the effect which added the blade tip bending increase.

FIG. 4 shows an embodiment in which the blade tip of the once-through fan shown in FIG. 1 is improved. The broken line shows the conventional shape,
The solid line shows the shape of this embodiment. The blade 14 shown in FIG. 4 is an example in which the cross section is made of aluminum or a steel plate and has the same thickness, and the tip of the outer peripheral side, which is about 10% of the blade length along the curvature, has most of the inside curvature. It has a curvature Rb that is slightly stronger in the direction of rotation than Ra,
An angle formed by a tangent line of a center line OP connecting the tip thickness midpoint P of the blade 14 through the center O of the impeller and a tangent line of the tip thickness midpoint P of the blade 14,
That is, the outer peripheral inlet angle Bb1 is about 1 compared to the conventional Ba1.
It is made to be too small by 0 °.

Next, regarding the blade shape shown in FIG. 4, the effect of bending the tip will be described with reference to velocity triangles shown in FIGS. 5 (a) and 5 (b). In FIG. 5 (a), U1 is the peripheral velocity of the blade 14, V1 is the absolute inflow velocity of the portion where the ventilation resistance is small and the inflow of wind is fast, and W1 is the relative velocity between the wind and the blade, which is U1 and V1.
The vector sum α1 is the inflow angle of the fast inflow portion, which is the angle formed by W1 and U1. Further, in FIG. 5B, U2 (= U1) is the peripheral velocity of the blade 14, V2 is the absolute inflow velocity of the portion where the ventilation resistance is large and the inflow of the wind is slow, and W2 is the relative velocity between the wind and the blade. The vector sum of U2 and V2, α2 is the inflow angle of the part where the inflow of the wind is slow, and is the angle formed by W2 and U2.

The part where the inflow of wind is fast means the fin 13a on the heat exchanger 13 side (inlet opening 9) shown in FIG.
As shown in the velocity triangle of FIG.
The air inflow angle α1 with respect to the inlet angle Bb1 of the blade 14 is increased by δBa1 as compared with the conventional Ba1 to make it difficult to enter, and the inflow amount is reduced. The part where the flow of air is slow is the wake mainly consisting of the pipe 13b of the heat exchanger, and
As in the velocity triangle of (b), the inflow angle α2 of the wind with respect to the inlet angle Bb1 of the blade 14 is smaller than the conventional Ba1 by δBa2 to make the inlet angle Bb1 closer to the entrance, and to increase the inflow amount. do.

That is, the partial forward inclination of the blade tip is shown in FIG.
The wake velocity a mainly consisting of the fins 13a of the heat exchanger 13 and the wake velocity b mainly consisting of the pipe 13b are averaged,
The amount of inflow to the blades 14 is averaged to reduce pressure fluctuations and turbulence fluctuations when passing through the blades, thereby reducing the occurrence of rotating secondary sound 2NZ due to interference particularly due to the close arrangement of the heat exchanger 13. Further, by averaging, it is possible to obtain the effect of reducing the fluid sound of the wing portion in a wide frequency band in addition to the secondary sound of rotation 2NZ. In addition, the free vortex 12 generated from the front edge 6a of the front casing and the blade 1 due to a sudden inflow.
The effect similar to that in the case of the heat exchanger wake is also obtained with respect to the interference with No. 4, and the effect of reducing the generation of the rotating primary sound 1NZ can be obtained. Further, the partial increase of the forward inclination of the blade 14 can improve the strength of the impeller as well as the blade.

As for the blade shape of the embodiment shown in FIG. 4, the outer diameter is 90 mm and the axial length is 634 m, as described above.
m, the number of blades is 34, the inclination angle θ of the blades 14 is 2.6 °, the randomness δ is 1.43, and the tip of the outer peripheral blade, which is mainly a double circular arc in section, is inclined forward by 13 ° (previous history: 26). From 13 °)
The resin-made once-through fan was installed, the rotation was performed at 1242 rpm, and the noise was analyzed at a 10 Hz pitch. FIG. 9 shows the frequency (Hz) on the horizontal axis and the sound pressure level (dB) on the vertical axis, and shows the data of the equal curvature blade fan with a solid line and the data of the tip bending fan with a broken line.

As a result, as shown by the broken line in FIG. 9, in particular, the peak of the rotating secondary sound 2NZ was 20 dB in comparison with the fan of the previous embodiment of the normal equal curvature blade, whereas The fan with the blade tip bent was able to reduce it by 15 dB to 5 dB, and there was almost no difference from the ambient sound on the spectrum, and the peak disappeared. Further, accompanying the decrease in the secondary rotating sound 2NZ, the primary rotating sound 1NZ also decreased by 2 dB. , The noise over-all value was 39.5 dB instead of 39,5 dB,
It was confirmed that the reduction effect of 2 dB and the audibility were improved.
It should be noted that due to the forward inclination of the blades, the air volume is reduced by 3% at the same number of revolutions, but the fluid noise is also reduced over a wide frequency band other than the rotation noises 2NZ and 1NZ, and when comparing the actual effects with the same air volume, This means that a reduction effect of 1,2 dB in bar-hole value was obtained.

[Embodiment 1-3] FIG. 6 is an enlarged sectional view of a blade of a once-through fan according to still another embodiment of the first invention. FIG. 6 shows an embodiment in which the blade shape and blade tip of the cross-flow fan shown in FIG. 1 are improved. The broken line shows the conventional shape, and the solid line shows the shape of this embodiment. The blade 15 shown in FIG. 6 has a substantially crescent-shaped cross section that is often used in resin molded products, and the tip has a curvature R as in the example of FIG.
Bent to b'and the entrance angle on the outer peripheral side is about 10 ° compared to conventional Ba '
It is too small to be Bb '.

Even in the case of a substantially crescent-shaped cross section as shown in FIG. 6, the blade tip is partially bent along the camber line with an extra curvature of Rb 'to form the blade 15 shown in FIG. Similar effects can be obtained.

[Embodiment 2] FIG. 10 is a front view of a cross-flow fan according to an embodiment of the second invention. The cross-flow fan 21 shown in FIG. 10 is a resin-made small impeller 21 in which a large number of blades 22 are arranged in the circumferential direction on one surface of the support disk 23 near the outer circumference.
Regarding a, the tip of the blade 22 on the side opening in the axial direction is inserted into the back groove of the supporting disk 23 of another small impeller 21a, welded by ultrasonic vibration, and a plurality of them are connected to form a horizontally elongated cage shape. It is an impeller. Here, the blades 22 of the individual small impellers 21a have a predetermined inclination angle θ with respect to the parallel lines in the axial direction, and the blades 22 pass through the support disk 23 and the support disk 2 at the left end.
3 to the supporting disc 23 at the right end, the blades are linear and are oriented in the same direction at a predetermined inclination angle θ with respect to the parallel line in the axial direction.

In this embodiment, since the molding can be carried out in units of the small impeller 21a, a small molding die is sufficient. Wings 2
The inclined molding of No. 2 can be performed by slightly moving the mold that enters between the blades 22 while taking it in and out, so that there is an advantage that molding can be performed easily. Further, in terms of performance, the effect of reducing the rotation noise and the fluid noise can be obtained as in the above-mentioned embodiment.
Further, with respect to the blade, the same effects as those of the first embodiment of the invention can be enhanced including randomization of the blade row and reduction of the secondary rotation sound by partially bending the tip of the outer peripheral side forward.

In the embodiment shown in FIG. 10, the blades 22 are arranged in a straight line via the supporting discs 23. However, even if the blades are connected with the supporting discs being deviated in phase from each other, the conventional blades may be connected. In this embodiment, since the blades 22 themselves have an inclination in advance as compared with a connected product in which the blades parallel to the axial direction have a stepwise phase shift, the flow phases are dispersed in the entire impeller. As a result, it is possible to reduce adverse effects around the supporting disk, to smooth the flow, and to reduce low-frequency vibration and its rotating sound accompanying rotation of the blade body.

[0045]

As described in detail above, according to the present invention, the discontinuous fluid noise near the supporting disk of the blade is reduced, the air volume fluctuation is reduced, and the low frequency associated with the rotation of the impeller is reduced. This reduces the rotating sound of the fan, and mainly reduces the rotating primary sound related to the number of blades with a high frequency, and accompanying it reduces the rotating secondary sound related to the number of blades. Can be provided. Further, according to the present invention,
By using the above-mentioned cross-flow fan, the secondary noise generated in the downstream of the heat exchanger is mainly reduced to reduce the noise and the size of the product, thereby saving resources or energy. It is possible to provide an air conditioner that can also contribute.

[Brief description of drawings]

FIG. 1 is a front view of a cross-flow fan according to an embodiment of the first invention.

FIG. 2 is a sectional view of the impeller of FIG. 1 taken along the line AA.

FIG. 3 is a vertical cross-sectional view of an air conditioner including the cross-flow fan shown in FIGS.

FIG. 4 is an enlarged sectional view of a blade of a cross-flow fan according to another embodiment of the first invention.

FIG. 5 is a velocity triangle diagram for explaining an inflow situation into the blade of FIG. 4;

FIG. 6 is an enlarged sectional view of a blade of a cross-flow fan according to still another embodiment of the first invention.

7 is a diagram of noise analysis results showing the effect of the blade having continuous skew in the cross-flow fan of the embodiment of FIG. 1. FIG.

FIG. 8 is a diagram of noise analysis results showing the effect of the cross-flow fan of the embodiment of FIG. 1 having a double-arc blade with a random pitch.

9 is a diagram of noise analysis results showing the effect of adding additional blade tip bending to the once-through fan of the embodiment of FIG.

FIG. 10 is a front view of a cross-flow fan according to an embodiment of the second invention.

FIG. 11 is a front view of a conventional cross-flow fan.

12 is a cross-sectional view taken along the line BB of FIG.

13 is a vertical cross-sectional view of a conventional air conditioner including the cross-flow fan of FIG.

[Explanation of symbols]

1 ... Once-through fan, 2 ... Wing, 3 ... Supporting disc, 4 ... Shaft, 6 ...
Front casing, 7 ... Rear casing, 9 ... Entrance opening, 1
0 ... Exit opening, 13 ... Heat exchanger, 13a ... Fin portion,
13b ... pipe part, 14,15 ... wing.

Claims (13)

[Claims] 1. A cross-flow fan in which a large number of blades are arranged in the circumferential direction near the outer circumference of a plurality of supporting discs arranged at predetermined intervals in the axial direction, wherein each of the individual blades is provided in the plurality of supporting circles. The plate is inclined in the same direction at a predetermined angle with respect to the parallel line in the axial direction from the disc at one end to the disc at the other end, and the multiple blades are arranged at a random pitch in the circumferential direction. A once-through fan featuring. 2. The cross-flow fan according to claim 1, wherein each of the blades has a tip on the outer peripheral side in the cross-sectional shape of the blade inclined in the rotational direction with a curvature slightly stronger than the curvature inside thereof. . 3. A cross-flow fan in which a large number of blades are arranged in the circumferential direction near the outer circumference of a plurality of supporting discs arranged at predetermined intervals in the axial direction, wherein the individual blades are provided in the plurality of supporting circles. The blade is inclined in the same direction at a predetermined angle with respect to the parallel line in the axial direction from the disc at one end to the disc at the other end, and the tip of the blade on the outer peripheral side in the cross-sectional shape is slightly smaller than the inner curvature. A cross-flow fan characterized by being tilted in the direction of rotation with a strong curvature. 4. A cross-flow fan in which a large number of blades are arranged in the circumferential direction near the outer circumference of a plurality of support discs arranged at predetermined intervals in the axial direction, wherein the plurality of blades have a random pitch in the circumferential direction. The cross-flow fan is characterized by arranging in the above, and the tip on the outer peripheral side in the cross-sectional shape of the blade is inclined in the rotation direction with a curvature slightly stronger than the curvature inside thereof. 5. A cross-flow fan in which a plurality of integrally-formed small impellers, each of which has a plurality of blades arranged in the circumferential direction, are axially connected to one surface near the outer circumference of a supporting disk in the cross-flow fan. The blades are those that, through the supporting discs, are inclined linearly and in the same direction at a predetermined angle with respect to the axial parallel line extending from the disc at one end to the disc at the other end of the plurality of supporting discs. A once-through fan characterized by being present. 6. A cross-flow fan comprising a plurality of integrally-formed small impellers, each of which is formed by arranging a number of blades in the circumferential direction, on one surface near the outer circumference of a supporting disk in an axial direction. A cross-flow fan, characterized in that a large number of blades of the impeller are inclined in the same direction at a predetermined angle with respect to the axial direction. 7. The cross-flow fan according to claim 5, wherein the plurality of blades are arranged in a circumferential direction at a random pitch. 8. The blade according to claim 5, wherein a large number of blades are inclined in a rotational direction with a curvature slightly larger than a curvature on the outer peripheral side in a cross-sectional shape of the blade. One-through fan. 9. A large number of blades are arranged at a random pitch in a circumferential direction, and a tip end on an outer peripheral side in a cross-sectional shape of the blade has a curvature slightly larger than a curvature inside thereof in a rotational direction. The cross-flow fan according to claim 5, wherein the cross-flow fan is inclined. 10. The cross-flow fan according to claim 1, wherein each blade has an inclination angle θ of 1 to 4.5 ° with respect to the axial direction of the impeller. 11. A large number of blades have a circumferential randomness δ.
The cross-flow fan according to claim 1, 4, 7, or 9, wherein (maximum pitch / minimum pitch) is set to 1.2 to 1.5. 12. The blade has an inclination angle θ of 1 to 4.5 ° with respect to the axial direction of the impeller and a circumferential randomness δ (maximum pitch / minimum pitch) of 1.2 to 1.5. The cross-flow fan according to any one of claims 1 to 9, characterized in that. 13. The cross-flow fan according to claim 1, wherein the cross-flow fan is provided on the inlet opening side thereof.
A cross fin pipe type heat exchanger having a cross-sectional configuration having at least two bent portions and surrounding the cross-flow fan is disposed, and a suction opening is provided in a casing at a position corresponding to the heat exchanger. And an air conditioner.