JPH06299994A - Multiblade fan - Google Patents

Abstract

PURPOSE:To provide a multibalde fan capable of reducing the turbulence flow noise which is generated in the in flow at the blade inlet part of a main plate side and at the blade inlet part of a side plate side. CONSTITUTION:A plurality of blades 104 which are mounted so as to be held by a main plate 102 and an annular side plate 103 are provided, and the part of 30-40% of the total blade width in the axial direction is made boundary from the side plate 103 toward the main plate 102, a blade inlet part 107 is divided on the side plate side and the main plate side from the boundary, and the different inlet angle can be set thereby.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-blade fan used for ventilation blowers and air conditioners.

[0002]

2. Description of the Related Art In recent years, in ventilation and air-blowing equipment and air-conditioning equipment used in living and non-living spaces, the number of equipment using a multi-blade fan is increasing, and there is a demand for lower noise.

Conventionally, this type of multi-blade fan has a structure in which an inlet angle and an outlet angle in the axial direction of a blade arranged so as to be sandwiched between a main plate and a side plate of an impeller have one inlet angle and one outlet angle. It was common.

The structure will be described below with reference to FIGS. 14 to 17.
Will be described with reference to. Shaft as shown
A main plate 102 connected to 101, an annular side plate 103,
The cross-sectional shape is the same from the main plate 102 side to the side plate 103 side.
And the entrance angle β ₁And exit angle β₂Are the same
The impeller 105 is configured so that a large number of raids 104 are sandwiched.
ing.

In the above structure, the suction side air 106 is sucked into the blade inlet 107 by applying a driving force to the shaft 101 to rotate the blade 104, the pressure is increased by the blade 104, and the blade outlet 108 is discharged. The liquid is discharged to the discharge port 110 through the scroll 109.

[0006]

In such a conventional multi-blade fan, when used in a low static pressure or large air volume region, the flow of the suction side air 106 from the suction port 111 to the blade 104 is accompanied by bending. Is the main plate 102
From the blade inlet portion 107 in the side plate 103
Does not flow evenly into the main plate 102, and most of the flow does not flow into the main plate 102 side, and part of it flows into the side plate 103 side.
In the blade inlet 107 _a side, the difference of the inflow angle of the side plate side inlet relative velocity W _1-a inlet angle beta ₁ is increased, vortices and Uzuon to the blade rear there is a problem that occurs.

Further, the vortex generated in the blade inlet 107 _a part is redeposited on the negative pressure surface 108 _an, of the blade outlet portion 108 _a of the side plate 103 side, noise is generated by the increase in pressure fluctuation at the time the and a problem that, the turbulence noise behind the suction surface 108 _an, at the blade outlet 108 _a by the eddy flowing out without reattachment a problem to increase.

Further, when the blade inlet angle beta ₁ to match the inflow angle of the side plate side inlet relative velocity W _1-a to prevent the vortex generated at the blade inlet 107 _a,
The difference between the blade inlet angle β _{1 and} the inlet angle of the main plate side inlet relative velocity W _{1 −b} at the blade inlet portion 107 _b, which is the mainstream area, becomes large, and the blade inlet portion 1 in the mainstream area 1
Vortex and Uzuon there has been a problem that occurs in 07 _b.

Further, the blade inlet angle β₁The side plate side
Inflow relative velocity W_1-aMatch the inflow angle of the
Mouth 107_aBlade exit angle β₂
Is smaller, the turning angle in the blade cross section is larger.
The blade inlet portion 107 _aTo blade outlet 1
08_aSeparation phenomenon occurred on the suction surface side while the flow progressed to
The blade outlet portion 108_aAnd vortex and vortex sound in the rear
There was a problem that occurs.

Further, increasing the blade outlet angle beta _2, it is possible to prevent the vortex generated at the rear of the blade outlet 108 _a, the absolute velocity at the blade outlet portion 108 _b of the main flow region is particularly effective work area Since the circumferential component C _{u2 of} is decreased and the work amount is also decreased, it is necessary to increase the rotation speed in order to obtain an equal air flow amount. Therefore, there is a problem that noise is generated due to the increase in the rotation speed.

Further, there is a problem that interference noise (NZ sound) is generated by the passage of the impeller 105 at the tongue portion 112, which is the closest portion between the impeller 105 and the scroll 109.

[0012] The present invention is intended to solve the above problems, to reduce eddy and Uzuon generated in the blade inlet 107 _a or the blade inlet 107 _b and the first object.

The second purpose is, for the most part, the blade inlet section 1.
07 flow with the bending of the suction-side air 106 flowing into the _b uniformly was flowing to the blade inlet 107 is to increase the effective working vane width.

A third object of the bladed outlet 108 _a from the blade inlet 107 _a, the by peeling phenomenon occurs at the negative pressure surface side of the middle of the flow proceeds blade outlet 1
It is to reduce vortices and vortex sounds at 08 _a and behind.

A fourth object is to prevent the decrease of the work amount due to the decrease of the circumferential direction component C _u2 of the absolute velocity at the blade outlet portion 108 _b which is the main flow region when the blade outlet angle β ₂ is increased, and to suppress the rotation speed. It is to prevent the noise from rising with the rise.

A fifth object is that the impeller 105 has the tongue 112.
The purpose is to reduce the interference noise (NZ sound) that occurs when passing through.

[0017]

According to the multi-blade fan of the present invention, a first means for achieving the above-mentioned first object comprises a plurality of blades mounted so as to be sandwiched by a main plate and an annular side plate, A portion of 30 to 40% of the total blade width in the axial direction from the side plate to the main plate is defined as a boundary, and the blade inlet portion is divided on the side plate side and the main plate side from the boundary to have different inlet angles. .

A second means for achieving the first object is a structure in which a continuous portion in which different inlet angles are continuously connected is arranged at the boundary of the blade inlet portion.

A third means for achieving the first, second, third and fourth objects is to arrange an intermediate side plate for separating and fixing the blade on the main plate side and the side plate side at the boundary,
At the blade outlet, the main plate side and the side plate side have different outlet angles.

The fourth means for achieving the first, second, third and fourth objects is such that the outer and inner diameters of the impeller are increased from the main plate of the impeller to the side plates. To do.

The fifth means for achieving the first, second, third and fourth objects is an extension bending in which the end of the intermediate side plate on the blade inlet side is extended and bent toward the side plate. It has a structure in which parts are arranged.

Also, the first, second, third, fourth and fifth
A sixth means for achieving the object of is that, in the blades on the main plate side and the side plate side separated by the intermediate side plate, the arrangement of the blades on one side is shifted by a half pitch with respect to the arrangement of the blades on the other side. It is arranged.

Also, the first, second, third, fourth and fifth
A seventh means for achieving the above object is to arrange the blades on the main plate side and the side plate side separated by the intermediate side plate by changing the number of blades on one side to the number of blades on the other side. It will be configured.

Also, the first, second, third, fourth and fifth
The eighth means for achieving the above-mentioned object is configured such that the blades on the main plate side and the side plate side separated by the intermediate side plate are arranged so as to be inclined in the circumferential direction.

[0025]

According to the present invention, in the blade inlet portion divided by the constitution of the above-mentioned first means, the blade inlet angles can be set which respectively match the inflow relative velocity on the side plate side and the inflow relative velocity on the main plate side from the division boundary, It is possible to prevent the generation of vortices and vortex sounds at the blade entrance.

In addition to the function of the first means, the second means makes it possible to reduce the turbulence of the inflow of air generated in the vicinity of the division boundary due to the continuous portion arranged at the division boundary.

In addition to the function of the first means, the blade outlet angles of the side plate side and the main plate side from the intermediate side plate can be set differently by the configuration of the third means. Therefore, the blade outlet angle can be appropriately set. The separation phenomenon that occurs on the suction surface side during the flow from the inlet to the blade outlet and the rotation speed at the required air volume due to the decrease in work when the outlet angle is set large over the entire blade width to prevent separation Can be prevented.

In addition to the function of the first means, the construction of the fourth means makes the suction port diameter larger toward the side plate from the main plate than the conventional fan having the same outer diameter of the blades, so that the suction side air shaft The directional inflow velocity is reduced, and the flow to the main plate side flowing into the blade inlet is alleviated and also flows to the side plate side. Therefore, the effective operating vane width is increased, the efficiency is improved, the number of revolutions at the same air volume can be reduced, and the absolute amount of noise can be reduced.

Further, in addition to the function of the third means by the structure of the fifth means, the flow near the boundary is smoothly welcomed by the extended bent portion, and the turbulence of the flow near the intermediate side plate is prevented and noise is reduced. You can

Further, in addition to the function of the fifth means, the amount of interference sound (NZ sound) with the impeller when passing through the tongue is 2/3 to 1 of that of the conventional structure. It becomes / 2 and can be reduced.

Further, in addition to the function of the fifth means, the structure of the seventh means disperses the generation frequency of the interference sound (NZ sound) with the impeller when passing through the tongue portion to reduce the generation amount. be able to.

In addition to the function of the fifth means, the structure of the eighth means can significantly reduce the amount of interference sound (NZ sound) with the impeller when passing through the tongue. .

[0033]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to FIGS. The same parts as those in the conventional example are designated by the same reference numerals, and detailed description thereof will be omitted.

As shown in the figure, the side plate 10 of the impeller 105 is shown.
3 to 30 to 40% of the total blade width W from the main plate 102
With the region of 1 as the boundary 1 and the blade inlet 107 as the side plate 10
3 side of the split in the blade inlet 107 _a main plate 102 side blade inlet 107 _b, in radial cross-section of A-A of the blade 104, the side plate 103 side of the blade inlet angle beta _1-U and the main plate 102 side blade Entrance angle β
_1-L is arranged.

With the above structure, when the impeller 105 is used in a low static pressure or large air volume region, most of the flow of the suction side air 106 accompanied by the bending is the blade inlet portion 107 _b.
(Hereinafter referred to as “inlet part 107 _b” ) and a part thereof flows into the blade inlet part 107 _a (hereinafter referred to as “inlet part 107 _a” ). At this time, the inflow absolute velocity C _m1-a in the radial direction at the time of inflow, the inlet portion 107 _a towards said inlet portion 107 _b
The inlet angle of the inlet relative velocities W _1-a and W _1-b from the velocity triangle becomes smaller than the inlet 1
07 _a is significantly smaller than the inlet 107 _b . However, since the inlet angles β _{1 -U} and β _{1 -L} can be matched to the respective inlet angles, the inlet portion 1
07 _a can be significantly prevent the occurrence of vortex generated, even be reduced also noise caused by eddy since the inlet portion 107 _b of the vortex generator can also be prevented by setting the appropriate inlet angles.

As described above, according to the multi-blade fan of the first embodiment of the present invention, the blade inlet portion is divided into the side plate side and the main plate side, and different inlets are provided so as to match the inflow relative speeds of the side plate side and the main plate side. By setting the angle, it is possible to significantly prevent the generation of vortices and vortex sounds at the blade entrance.

Next, a second embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIGS. 3 and 4. The same parts as those in the first embodiment are designated by the same reference numerals, and detailed description thereof will be omitted.

As shown in figure, in the blade 104 has a structure which arranged continuous portion 4 connecting the inlet portion 107 _a ends 2 and the inlet portion 107 _b end 3 of the border 1.

With the above structure, the air flow in the vicinity 1 _ab of the boundary 1 flows from the positive pressure surface to the negative pressure surface of the end portion 2 and the end portion 3, which is a concern when there is no continuous portion 4. It is possible to cut off the unnecessary flow 5 to prevent an increase in pressure fluctuation and reduce noise.

If the continuous portion 4 is formed so that the end portion 2 and the end portion 3 are smoothly continuously formed in the axial direction of the blade 104 with a slight continuous width, a secondary air flow in the continuous portion 4 is generated. The flow 5 is more smoothly welcomed to further reduce noise.

As described above, according to the multi-blade fan of the second embodiment of the present invention, the air flow in the vicinity 1 _ab of the boundary 1 is concerned when the end portion 2 is absent when the continuous portion 4 is not present.
Moreover, it is possible to prevent the generation of noise due to the turbulence of the flow and the increase of the pressure fluctuation in the end portion 3, and it is possible to achieve the noise reduction of the first embodiment or more.

Next, a third embodiment of the present invention will be described with reference to FIGS. The same parts as those in the first embodiment are designated by the same reference numerals, and detailed description thereof will be omitted.

As shown in the figure, the side plate 103 to the main plate 10
2, the blade 104 is completely separated and fixed to the side plate 103 side and the main plate 102 side with a portion of 30 to 40% of the total blade width W as a boundary.

In the above structure, the blade 104 is completely separated into the side plate 103 side and the main plate 102 side by the intermediate side plate 6, so that the inlet angles β ₁ -U and β _{1 -L} and the outlet angle β ₂ -U are set. β _2-L can be set independently. Impeller 105
When using a low static pressure or large air volume, suction side air 1
Most of the flow with the bend 06 flows into the inlet portion 107 _b and a part thereof flows into the inlet portion 107 _a .
The inflow angle at 07 _a is obviously smaller than the inflow angle at the inlet 107 _b . Therefore, by setting the inlet angle β ₁ -U on the side plate 103 side and the inlet angle β ₁ -L on the main plate 102 side to match the respective inflow angles, the inlet portion 107 _a and the inlet portion 107 _b are It is possible to prevent the generation of whirlpools and whirlpool sounds. On the other hand, the blade outlet 108 _a (hereinafter outlet 108 _a), the inlet portion 107 _a the inlet angle beta _1-U is less set the outlet portion 108 so as not blade turning angle is large since _a the By setting the outlet angle β ₂ -U large, it is possible to prevent the separation phenomenon on the blade negative pressure surface. Also the blade outlet portion 108 _b (hereinafter referred to as the outlet portion 108 _b), the inlet angle at the inlet portion 107 b beta
_{Since 1-L} is set larger than the inlet angle β ₁ -U, the outlet angle β _{1 -L} can be set smaller than the outlet angle β ₁ -U even if the turning angle is taken into consideration. Therefore, the total blade width W
In the above, the work amount is increased and the rotational speed can be reduced as compared with the case where the outlet angle is set to the outlet angle β ₁ -U.

As described above, according to the multi-blade fan of the third embodiment of the present invention, the inlet angles β _1-U and β _1-L and the outlet angles β _1-U and β _1-L are set to the inlet angle, By making appropriate settings in consideration of the prevention of the decrease in turning angle and the amount of work, the generation of noise can be prevented and the noise reduction of the second embodiment or more can be achieved.

Next, a fourth embodiment of the present invention will be described with reference to FIGS. 7 and 8. The same parts as those in the first embodiment are designated by the same reference numerals, and detailed description thereof will be omitted.

As shown in the figure, the outer diameter D of the blade is determined by the main plate 102.
From the side to the side plate 103, the size is increased.

In the above structure, the flow of the suction side air 106 accompanied by the bending is accompanied by the increase of the outer diameter D of the blade, and the impeller 1
Since also increases the suction aperture and the suction cross-sectional area of 05 axial inflow velocity of the suction side air 106 is reduced than the conventional impeller, the flow of the main plate 102 side entering the inlet portion 107 _b is relaxed side plates 103 to flow to the side of the inlet 107 _a. Therefore, the effective operating vane width is increased, the efficiency is improved, the number of revolutions at the same air volume can be reduced, and the absolute amount of noise can be reduced.

As described above, according to the fourth embodiment of the present invention, the effective operating blade width can be increased by increasing the blade outer diameter D from the main plate 102 side toward the side plate 103 side, and the third embodiment. The above noise reduction can be achieved.

Next, a fifth embodiment of the present invention will be described with reference to FIG. The same parts as those in the first embodiment are designated by the same reference numerals, and detailed description thereof will be omitted.

As shown in the drawing, the end portion 7 of the intermediate side plate 6 on the side of the blade inlet 107 is extended and an extended bent portion 8 is provided which is bent toward the side plate 103 in the axial direction.

In the above-mentioned structure, the flow flowing into the vicinity of the intermediate side plate 6 is smoothly welcomed by the extension bent portion 8, so that there is a turbulence of the flow at the end portion 7 which is feared when the extension bent portion 8 is not provided. It is possible to prevent the generation of vortices.

Thus, according to the fifth embodiment of the present invention,
By providing the extension bent portion 8, it is possible to prevent a vortex at the end portion 7 and to reduce the noise as compared with the third embodiment.

Next, a sixth embodiment of the present invention will be described with reference to FIG.
Will be described with reference to. The same parts as those in the first embodiment are designated by the same reference numerals, and detailed description thereof will be omitted.

As shown in the drawing, the blade 10 separated by the intermediate side plate 6 into the side plate 103 side and the main plate 102 side.
The 4 _U and the blade 104 _L are arranged so that they are displaced from each other by ½ pitch.

In the above-mentioned structure, the impeller 1 is rotating during operation.
When 05 passes through the tongue 112, when the blades 104 _U pass through the closest approach portion 9 at the same time, the blades do not pass the full width at the same time in the closest approach portion 9, and the blade 104 _L is The blades 104 _L do not pass because they are displaced from each other, and similarly, when the blade 104 _L passes through the closest portion 9, the blade 104 _U does not pass. Therefore,
The amount of interference noise (NZ sound) with the blade at the closest portion 9 of the tongue portion 112 is about 2/3 to 1 of that of the conventional one because the simultaneous passing blade length of the tongue portion 112 can be shortened.
It can be reduced to / 2.

As described above, according to the sixth embodiment of the present invention,
By reducing the width of the blade blade when passing through the tongue portion 112, it is possible to reduce the amount of interference noise generated between the impeller 105 and the tongue portion 112, and it is possible to achieve a noise reduction lower than that of the fifth embodiment.

Next, the seventh embodiment of the present invention will be described with reference to FIG.
Will be described with reference to. The same parts as those in the first embodiment are designated by the same reference numerals, and detailed description thereof will be omitted.

As shown in the figure, the number Z _a of the blades 104 _U on the side plate 103 side separated and fixed by the intermediate side plate 6 is Z _a ,
The relationship between the number Z _b of blades 104 _L on the main plate 102 side and the conventional number Z of blades is

[0060]

[Equation 1]

The arrangement is as follows.

In the above structure, the arrangement pitch P _a of the blades 104 _{U on} the side plate 103 side and the arrangement pitch P _b of the blades 104 _L on the main plate side 102 side are respectively constant, but the pitches of the blades 104 _U and 104 _L are the same. Since the pitches are unequal, the length of the simultaneous passing blades when passing through the closest portion 9 of the tongue 112 is not constant, so that the generation frequency of the interference noise with the impeller 105 at the tongue 112 is dispersed and generated. The quantity also decreases.

As described above, according to the seventh embodiment of the present invention,
By disposing the blades differently in number Z _a and Z _b, it is possible to reduce the interference noise (NZ noise) with the impeller at the tongue 112, and it is possible to reduce the noise more than in the fifth embodiment.

Next, FIG. 12 shows the eighth embodiment of the present invention.
The description will be made with reference to FIG. The same parts as those in the first embodiment are designated by the same reference numerals, and detailed description thereof will be omitted.

As shown in the figure, the blades 104 _U and 104 _L separated by the intermediate side plate 6 are arranged so as to be inclined in the circumferential direction (rotational direction).

In the above structure, since the length of the simultaneous passing blades when passing through the tongue 112 is very small, the amount of interference noise with the impeller 105 at the closest portion 9 of the tongue 112 is large. Can be reduced to

Thus, according to the eighth embodiment of the present invention,
By inclining the blades 104 _U and 104 _L in the circumferential direction, the interference noise of the tongue portion 112 with the impeller 105 can be significantly reduced, and the noise reduction of the fifth embodiment or higher can be achieved.

[0068]

As is apparent from the above embodiments, according to the present invention, among the fluid noises generated from the multi-blade fan, turbulent noises, mainly vortex noises, and blade passing noises at the tongue are reduced. It is possible to provide a multi-blade fan with an effect that can be achieved.

[Brief description of drawings]

FIG. 1 is a side sectional view of a multi-blade fan according to a first embodiment of the present invention.

FIG. 2 is a sectional view of the same main part.

FIG. 3 is a sectional view of an essential part of the second embodiment.

[Fig. 4] Side view of the main part

FIG. 5 is a side sectional view of the third embodiment.

FIG. 6 is a sectional view of the same main part.

FIG. 7 is a side sectional view of the fourth embodiment.

FIG. 8 is a sectional view of the same main part.

FIG. 9 is a side sectional view of the fifth embodiment.

FIG. 10 is a sectional view of the essential parts of the sixth embodiment.

FIG. 11 is a sectional view of the essential parts of the seventh embodiment.

FIG. 12 is a sectional view of an essential part of the eighth embodiment.

FIG. 13 is a side view of the same.

FIG. 14 is a front view of a conventional multi-blade fan.

FIG. 15 is a sectional view of the same side.

FIG. 16 is a sectional view of the main part of the same.

FIG. 17 is a sectional view of the same main part.

[Explanation of symbols]

1 Boundary 4 Continuous part 6 Intermediate side plate 7 End part 8 Extended bent part 102 Main plate 103 Side plate 104 Blade 104 _U blade 104 _L blade 107 Blade inlet part 107 _a Blade inlet part 107 _b Blade inlet part 108 Blade outlet part 108 _a Blade outlet part 108 _b blade outlet

Claims (8)

[Claims] 1. A blade inlet provided with a plurality of blades mounted so as to be sandwiched by a main plate and an annular side plate, with a portion of 30-40% of the total blade width in the axial direction extending from the side plate toward the main plate as a boundary. A multi-blade fan having a different inlet angle by dividing the part into the side plate side and the main plate side from the boundary. 2. The multi-blade fan according to claim 1, further comprising a continuous portion in which different inlet angles are continuously connected at a boundary of the blade inlet portion. 3. The multi-blade fan according to claim 1, further comprising an intermediate side plate for separating and fixing the blade on the main plate side and the side plate side at the boundary, and having different outlet angles on the main plate side and the side plate side at the blade outlet portion. . 4. The multi-blade fan according to claim 3, wherein the outer diameter and the inner diameter of the impeller are increased from the main plate of the impeller toward the side plates. 5. A multi-blade fan according to claim 3, wherein an end portion of the intermediate side plate on the blade inlet side is extended and an extended bent portion is bent toward the side plate. 6. The blades on the main plate side and the side plate side separated by the intermediate side plate are arranged such that the arrangement of the blades on one side is shifted by a half pitch from the arrangement of the blades on the other side. Multi-wing fan. 7. The multi-blade fan according to claim 5, wherein the main plate side blades and side plate side blades separated by the intermediate side plate are arranged such that the number of blades on one side is different from the number of blades on the other side. . 8. The multi-blade fan according to claim 5, wherein the blades on the main plate side and the side plate sides separated by the intermediate side plate are arranged so as to be inclined in the circumferential direction.