CN111648998A - Blade structure of centrifugal blower - Google Patents

Abstract

The present invention provides a blade structure of a centrifugal blower capable of obtaining blowing efficiency and noise reduction effect. In this centrifugal blower, a plurality of vanes are erected between a back plate and a shroud arranged at a predetermined interval from the back plate, wherein the vanes have leading edges in the rotational direction of the vanes on the back plate side and the shroud side. The vicinity of the torsion shape is a twisted shape that is curved in the outer circumferential direction in the vicinity of the backrest plate and the shroud of the blade, the subsequent part of the blade connected to the twisted shape is the same cylindrical plane, and the leading edge of the blade is in the same cylindrical plane. The shape of the edge is a curved shape in which the center portion is recessed, and the center portion in the width direction of the blade is also the same cylindrical plane from the leading edge portion to the subsequent portion.

Description

Blade structure of centrifugal blower

technical field

The present invention relates to a blade structure of a centrifugal blower used in an air conditioner or the like.

Background technique

Centrifugal blowers such as conventional multi-blade fans and centrifugal fans (Japanese: プラグファン) are composed of a combination of a suction part of an impeller with a plurality of blades erected between a shroud on the air suction side and a back plate on the motor side and a fan suction port. The structure uses the rotation of the motor to rotate the impeller to blow air.

The centrifugal blower is often used for blowing air of an air-conditioning apparatus, etc., as shown in Patent Document 1, and a conventional conventional centrifugal blower is illustrated in FIGS. 1 to 4 .

As shown in FIG. 2 , it is a structure in which the suction part e of the impeller d including the shroud a, the vane b, and the back plate c in FIG. 1 is combined with the fan suction port g. The motor shaft h is fastened to the back plate c of the impeller d by a hub or the like (fastening joint) j, and the impeller d is rotated by the rotation of the motor i.

Here, the shape of the blade b is the shape shown in FIGS. 3 to 4 , and the whole is a shape in which a part of the column as shown in FIG. 1 and FIG. 3 is cut away. It is arrange|positioned so that it may incline toward the discharge part f of the outer periphery from the suction part e (refer FIG. 1). In FIG. 3 , the lower side is the straight line b1 along the back plate c, the upper side is the shape along the inner surface of the shroud a, and the vicinity of the suction part e on the right side in FIG. 3 is the bulging shape b2. The horizontal edge b3 is connected to each other, the front edge which cuts off the wind is the straight line b4, and the rear edge is also the straight line b5 in the vertical direction.

The sectional view of the blade b in Fig. 3 along the sectional lines AA', BB', CC' is Fig. 4 .

In this way, in FIG. 4 , the cross-sections of the blade b along the cutting lines AA', BB', and CC' have the same shape, and the same blade cross-sectional shape is continuous in the width direction of the blade. The blade shape is easy to manufacture, but the airflow turbulence is generated in the flow path between the blade leading edge and the blade, which reduces the blowing efficiency of the fan and generates noise due to wind noise.

prior art literature

Patent Literature

Patent Document 1: Japanese Patent Laid-Open No. 2013-96378

SUMMARY OF THE INVENTION

Invention to solve problem

The present invention has been made in view of the above-mentioned problems, and, in view of the fact that it is expected to improve the blowing efficiency even if the shape of the upper and lower width directions of the blades is changed, it is intended to provide a method by making the upper and lower width directions of the blades The blade structure of the centrifugal blower can be obtained by changing the shape of the centrifugal blower to obtain the blowing efficiency and noise reduction effect.

solution to the problem

In order to solve the above-mentioned problems, the invention of claim 1 is a centrifugal blower in which a plurality of blades are erected between a back plate and a shroud arranged at a predetermined interval from the back plate, wherein the The vicinity of the front edge portion in the rotation direction of the blade on the back plate side and the shroud side of the blade has a twisted shape, and the torsion shape is curved in the outer peripheral direction in the vicinity of the back plate and the shroud of the blade. The subsequent parts connected in the twisted shape are the same cylindrical plane, and the shape of the edge of the front edge part is a curved shape with a concave central part.

The invention of claim 2 is a blade structure for a centrifugal blower, characterized in that the central part in the width direction of the blade is the same cylindrical plane from the leading edge part to the subsequent part.

In addition to the blade structure of the centrifugal blower according to claim 1 or 2, the invention of claim 3 is characterized in that the vicinity of the connecting portion between the front edge portion and the back plate of the blade extends in a gentle slope.

effect of invention

With the blade structure of the centrifugal blower of claim 1, the torsional shape of the leading edge of the blade is used to continuously reduce the inlet angle of the blade from the center in the width direction of the blade to the back plate and the shroud, so that the airflow at the leading edge of the blade is reduced. The inflow state of the air flow is improved, and not only the turbulent flow caused by the collision between the blades and the airflow can be suppressed, but also the turbulent flow of the entire flow path can be suppressed, and high efficiency and low noise can be achieved.

Furthermore, according to the blade structure of the centrifugal blower according to claim 2, in addition to the effect of claim 1, by extending the central portion in the width direction of the blade in a columnar shape in parallel with the width direction of the blade, it is possible to maintain the accuracy of the blade. The blade twist-shaped portion is effective for high efficiency and low noise, and the blade width can be changed, thereby making it possible to very easily manufacture a fan having the same impeller diameter and different air volumes while maintaining efficiency.

Furthermore, according to the blade structure of the centrifugal blower of claim 3, in addition to the effects of claim 1 or 2, the blade can be further improved by extending the vicinity of the connecting portion between the leading edge portion of the blade and the back plate in a gentle slope shape. The inflow state of the airflow in the vicinity of the back plate of the leading edge achieves further improvement in efficiency and reduction in noise.

Description of drawings

FIG. 1 is an explanatory perspective view of an impeller structure of a conventional centrifugal blower.

2 is a side view of a state in which a conventional centrifugal blower is assembled in an air conditioner.

FIG. 3 is a side view of the conventional blade in FIG. 1 .

FIG. 4 is a cross-sectional view of the blade of FIG. 3 along a cutting line.

5 is an explanatory perspective view of the impeller structure of the centrifugal blower according to the first embodiment of the present invention.

6 is a side view illustrating a portion of a section line of the blade in the blade unit of Example 1. FIG.

FIG. 7 is a cross-sectional view of the blade of Example 1 in FIG. 6 along each cutting line.

FIG. 8 is an explanatory diagram of the inlet angle α of the blade.

9 is an explanatory perspective view of the impeller structure of the centrifugal blower according to the second embodiment of the present invention.

FIG. 10 is a side view of the blade of Example 2 in FIG. 9 .

Description of reference numerals

1. Back plate; 2. Shroud; 3. Blade; 31. Lower side of blade; 312. Near the front edge of the back plate (Y1); 313. The gentle slope of the back plate side (X1); 32. The leading edge of the blade part; 321, curved part (X2); 33, the upper side of the blade; 331, the vicinity of the front edge of the shroud side (Y2); 332, the convex part; 34, the rear edge part of the blade; 4, the impeller; 5, the suction part ; 6. Discharge part; 7. Fan suction port

Detailed ways

Embodiments of the blade structure of the centrifugal blower of the present invention will be described with reference to the drawings, Embodiment 1 will be described with reference to FIGS. 5 to 8 , and Embodiment 2 will be described with reference to FIGS. 9 and 10 .

[Example 1]

Preferred Embodiment 1 of the blade structure of the centrifugal blower of the present invention will be described. The impeller 4 of the centrifugal blower of FIG. 5 is arranged in the blower chamber in the air conditioner with the same structure as shown in FIG. 2 as in the related art.

First, the vane 3 assembled to the impeller 4 of the first embodiment in FIG. 5 , which is combined with the fan suction port 7 , will be described.

The blades 3 of the impeller 4 are disposed at equal intervals between the back plate 1 and the shroud 2 so as to be inclined from the suction portion 5 toward the outer peripheral discharge portion 6 .

The blade lower side 31 of the blade 3 is shaped along the back plate 1, the blade upper side 33 is shaped along the inner surface of the shroud 2, and the blade upper side 33 has a raised protrusion near the suction part 5 that cuts off the air. Shape portion 332 .

In addition, the leading edge portion 32 of the blade in which the air is cut has a curved portion 321 ( X2 ) having a curve slightly concave inward, and a gently sloped portion 313 ( X1 ) is provided on the leading edge of the blade 3 The part 32 and the vicinity of the back panel suction part 5 of the back panel 1 extend forward. This gentle slope-shaped portion 31 ( X1 ) can suppress not only the turbulent flow due to the vanes and the airflow, but also the turbulent flow of the entire flow path, thereby achieving high efficiency and low noise. Likewise, the curved portion 321 (X2) is also shaped to suppress air turbulence. In addition, although the blade trailing edge portion 34 of the present embodiment is a straight line in the vertical direction, other shapes may be used.

In addition, as shown in FIG. 7 , the vicinity of the leading edge portion 312 in the rotation direction of the blade on the side of the backing plate 1 is a twisted shape Y1 (solid line), and the twisting direction is bent to the outer peripheral outer side in the vicinity of the backing plate 1, that is: AA 'Cross-sectional shape is curved more gently than the central CC' (broken line) cross-sectional shape, and is twisted to the outside of the outer periphery. Similarly, the vicinity of the leading edge portion 331 of the blade 3 in the blade rotation direction on the side of the shroud 2 also has a twisted shape Y2 (solid line), and the twist direction is curved to the outer peripheral outer side in the vicinity of the shroud 2 . When expressed by the numerical values of Example 1, for example, the vertical height of the blade 3 is 140 mm, and in FIG. 7 , the radius of curvature R3 at the leading edge of the CC' cross-sectional shape serving as a reference is set to 313.2 mm , the radius of curvature R1 at the front edge in the AA' cross-sectional shape is 333.2 mm, and the distance a1 is about 4.9 mm. In addition, the curvature radius R2 of the front edge portion in the EE' cross-sectional shape is 318.3 mm, and the distance a2 is about 1.7 mm.

By the twisted shapes Y1 and Y2 of the vicinity of the leading edge portions 312 and 331 , the blade inlet angle α is continuously reduced from the vertical width center portion (CC′) of the blade 3 to the back plate 1 and the shroud 2 . When this inlet angle α is described with reference to FIG. 8 , the angle formed by the tangent line at the center of the vane 3 ( FIG. 8 ) indicated by the dashed-dotted line and the vane inscribed circle R, that is, the inlet angle is α1, but by setting the front The vicinity of the edge is made into twisted shapes Y1 and Y2, and the entire blade leading edge (32) with the inlet angle α2 is close to the inflow angle of the air, so the inflow state of the airflow in the vicinity of the leading edge 312 and 331 of the blade 3 is improved. , not only can suppress the turbulent flow caused by the collision between the blade and the airflow, but also can suppress the turbulent flow of the entire flow path, and can achieve high efficiency and low noise.

[Example 2]

In the present invention, by adjusting the width of the belt at the center of the vertical width of the blade 3 in the impeller 4 of the centrifugal blower, the twisted shapes Y1 and Y2 near the leading edge portion can be kept as they are, and high efficiency and low noise can be maintained. , and the blade width (Z) can be easily changed. Therefore, the centrifugal fan corresponding to the designed air volume can be designed and manufactured.

Here, a second embodiment in which the vertical width of the impeller 4' is changed to have the blade width corresponding to the blowing volume will be described with reference to Figs. 9 and 10 .

9 is a perspective view of the impeller 4 ′ according to the second embodiment. As shown in FIG. 10 , the torsional shapes Y1 and Y2 near the leading edge portion of the blade 3 are the same as those of the first embodiment, and compared with the conventional partially cylindrical blades, The blowing efficiency is improved and the noise is also reduced. That is, when the vertical width of the blade 3 is changed, the vertical width z of the belt-shaped portion (the one-dot chain line CC'DD') in the central part of the blade 3 is expanded and contracted, and the overall vertical width Z can be extended. Alternatively, it may be shortened, and the twisted shapes Y1 and Y2 existing on the back plate 1 side and the shield 2 side may be kept as they are.

In this way, the blade width can be easily changed while maintaining the blade twist shape portion effective for high efficiency and noise reduction, and a fan having the same impeller diameter and different air volumes can be easily formed.

Because of the above structure, the blade structure of the centrifugal blower of each embodiment is adopted, and the blade inlet angle is continuously changed from the center in the blade width direction to the back plate and the shroud by utilizing the twisted shape of the blade leading edge. When the blade is small, the inflow state of the airflow at the leading edge of the blade is improved, and turbulence caused by the collision between the blade and the airflow can be suppressed, and the turbulent flow of the entire flow path can be suppressed, and high efficiency and low noise can be achieved.

In addition, by extending the central portion in the width direction of the blade in a columnar shape in parallel with the width direction of the blade, it is possible to maintain the blade twist shape portion effective for high efficiency and noise reduction, and even if the blade width is variable. The effect of blowing efficiency and noise reduction. Thereby, it is possible to very easily manufacture a fan having the same impeller diameter and different air volumes while maintaining efficiency.

Furthermore, since the vicinity of the connection between the leading edge of the blade and the back plate extends in a gentle slope, it is possible to further improve the inflow state of the airflow in the vicinity of the back plate of the leading edge of the blade, and achieve further higher efficiency and lower noise.

In addition, it goes without saying that the present invention is not limited to the above-described embodiments as long as the characteristics of the present invention are not destroyed. In the embodiments, the embodiment is applied to a blower of an air conditioner, but it can be used as a blower alone, for example.

Claims (3)

1. A blade structure of a centrifugal blower in which a plurality of blades are erected between a back plate and a shroud disposed at a predetermined interval from the back plate,

the blade has a twisted shape in the vicinity of the leading edge in the direction of rotation of the blade on the back plate side and the shroud side, the twisted shape being curved in the peripheral direction in the vicinity of the back plate and the shroud of the blade, the trailing portion of the blade connected to the twisted shape being the same cylindrical plane, and the edge of the leading edge having a curved shape in which the central portion is recessed.

2. The centrifugal blower vane construction of claim 1,

the central part of the blade in the width direction is the same cylindrical plane from the front edge part to the subsequent part.

3. The vane structure of a centrifugal blower according to claim 1 or 2,

the blade has a front edge portion and a back plate, and a portion near a connecting portion between the front edge portion and the back plate extends in a gentle slope.

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