CN111648998A

CN111648998A - Blade structure of centrifugal blower

Info

Publication number: CN111648998A
Application number: CN201910641193.1A
Authority: CN
Inventors: 上田和成; 日置达也
Original assignee: Sinko Kogyo Co ltd
Current assignee: Sinko Kogyo Co ltd
Priority date: 2019-03-04
Filing date: 2019-07-16
Publication date: 2020-09-11
Anticipated expiration: 2039-07-16
Also published as: CN111648998B; JP2020143580A; JP7217176B2

Abstract

The invention provides a blade structure of a centrifugal blower capable of obtaining blowing efficiency and noise reduction effect. The centrifugal blower is provided with a plurality of blades erected between a back plate and a shroud arranged at a predetermined interval from the back plate, wherein the vicinity of front edge portions of the blades on the back plate side and the shroud side in the rotation direction of the blades is a twisted shape which is curved in the outer circumferential direction in the vicinity of the back plate and the shroud of the blades, the subsequent portions of the blades connected to the twisted shape are the same cylindrical plane, the edge of the front edge portion is shaped into a curved shape in which the central portion is recessed, and the central portion of the blades in the width direction is also the same cylindrical plane from the front edge portion to the subsequent portions.

Description

Blade structure of centrifugal blower

Technical Field

The present invention relates to a vane structure of a centrifugal blower used for an air conditioner and the like.

Background

A conventional centrifugal blower such as a sirocco fan or a centrifugal fan (japanese: プラグファン) has a structure in which a suction portion of an impeller having a plurality of blades standing between a shroud on an air suction side and a back plate on a motor side is combined with a fan suction port, and air is blown by rotating the impeller by the rotation of the motor.

As shown in patent document 1, the centrifugal fan is often used for blowing air for an air conditioner, and a conventional common centrifugal fan is illustrated in fig. 1 to 4.

As shown in fig. 2, the impeller d of fig. 1 includes a shroud a, blades b, and a back plate c, and a suction portion e is combined with a fan suction port g. The motor shaft h is fastened to a 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 blades b have a shape shown in fig. 3 to 4, and a shape in which a part of a cylinder as shown in fig. 1 and 3 is cut out as a whole, and are disposed between the shroud a and the back plate c so as to be inclined from the suction portion e (see fig. 1) toward the discharge portion f on the outer periphery. In fig. 3, the lower side is a straight line b1 along the back plate c, the upper side is a shape along the inner surface of the shield a, the vicinity of the right suction portion e in fig. 3 is a bulging shape b2, and a horizontal edge b3 is provided in connection therewith, and the front edge that cuts off the wind is a straight line b4, and the rear edge is also a straight line b5 in the vertical direction.

The sectional view of the vane B in fig. 3 along the sectional lines a-a ', B-B ', C-C ' is fig. 4.

As described above, in fig. 4, the blade B has the same cross section along the respective sectional lines a-a ', B-B ', and C-C ', and the same blade cross-sectional shape is a continuous blade shape in the width direction of the blade, and is easy to manufacture.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2013-96378

Disclosure of Invention

Problems to be solved by the invention

The present invention has been made in view of the above-described problems, and it is an object of the present invention to provide a vane structure of a centrifugal blower in which an improvement in air blowing efficiency can be expected even when the shape of the vanes in the vertical width direction is changed, and air blowing efficiency and a noise reduction effect can be obtained by changing the shape of the vanes in the vertical width direction.

Means for solving the problems

In order to solve the above-described problems, the invention according to claim 1 is a 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, wherein vicinities of leading edge portions of the blades on a back plate side and a shroud side in a blade rotation direction are twisted shapes which are curved in an outer circumferential direction in vicinities of the back plate and the shroud of the blades, subsequent portions of the blades connected to the twisted shapes are on the same cylindrical plane, and a shape of an edge of the leading edge portion is a curved shape in which a central portion is recessed.

The invention according to claim 2 is a centrifugal blower blade structure characterized in that the central portion of the blade in the width direction is the same cylindrical plane from the leading edge portion to the trailing portion.

The invention according to claim 3 is the centrifugal blower blade structure according to

claim

1 or 2, wherein a vicinity of a connection portion between the leading edge portion of the blade and the back plate extends in a gentle slope.

ADVANTAGEOUS EFFECTS OF INVENTION

In the centrifugal blower blade structure according to claim 1, the inlet angle of the blade is continuously reduced from the center of the blade in the width direction to the back plate and the shroud by the twisted shape of the leading edge portion of the blade, so that the inflow state of the airflow at the leading edge portion of the blade is improved, and turbulence generated by collision between the blade and the airflow is suppressed, and turbulence in the entire flow path is also suppressed, thereby achieving high efficiency and low noise.

Further, according to the centrifugal blower blade structure of claim 2, in addition to the effect of claim 1, the central portion in the blade width direction can be extended in parallel in a cylindrical shape in the width direction of the blade, whereby the twisted shape portion of the blade effective for high efficiency and low noise can be maintained, and the blade width can be varied, whereby the centrifugal blower blades having the same impeller diameter and different air volumes can be manufactured very easily while maintaining efficiency.

Further, according to the centrifugal blower blade structure of claim 3, in addition to the effect of

claim

1 or 2, the vicinity of the connection portion between the front edge portion of the blade and the back plate is extended in a gentle slope shape, whereby the inflow state of the airflow in the back plate vicinity portion of the front edge of the blade can be further improved, and further high efficiency and noise reduction can be achieved.

Drawings

Fig. 1 is a perspective view illustrating an impeller structure of a conventional centrifugal blower.

Fig. 2 is a side view of a conventional centrifugal blower unit mounted on an air conditioner.

Fig. 3 is a side view of the conventional blade unit shown in fig. 1.

Fig. 4 is a cross-sectional view of the blade of fig. 3 taken along the cut-off line.

Fig. 5 is a perspective view illustrating the impeller structure of the centrifugal blower according to example 1 of the present invention.

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

Fig. 7 is a sectional view of the blade of embodiment 1 in fig. 6 along each sectional line.

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

Fig. 9 is a perspective view illustrating the impeller structure of the centrifugal blower according to example 2 of the present invention.

Fig. 10 is a side view of the blade of embodiment 2 in fig. 9.

Description of the reference numerals

1. A back plate; 2. a shield; 3. a blade; 31. the underside of the blade; 312. a back-panel-side front edge portion vicinity (Y1); 313. a back plate side gentle slope portion (X1); 32. a blade leading edge portion; 321. a curved portion (X2); 33. the upper side of the blade; 331. a shroud-side leading edge vicinity (Y2); 332. a convex-shaped portion; 34. a blade trailing edge portion; 4. an impeller; 5. a suction portion; 6. a discharge unit; 7. suction inlet of fan

Detailed Description

An embodiment of a blade structure of a centrifugal blower according to the present invention will be described with reference to the drawings, embodiment 1 will be described with reference to fig. 5 to 8, and embodiment 2 will be described with reference to fig. 9 and 10.

[ example 1]

In the description of preferred embodiment 1 of the blade structure of the centrifugal blower according to the present invention, the impeller 4 of the centrifugal blower of fig. 5 is disposed in the blower chamber in the air conditioning equipment in the configuration shown in fig. 2, similarly to the conventional one.

First, the description will be made starting from the blade 3 incorporated in the impeller 4 of embodiment 1 in fig. 5, and the impeller 4 is combined with the fan suction port 7.

The blades 3 of the impeller 4 are disposed between the back plate 1 and the shroud 2 at equal intervals in an inclined manner from the suction portion 5 toward the discharge portion 6 on the outer periphery.

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

The blade leading edge portion 32 that cuts open the air has a bent portion 321(X2), the bent portion 321(X2) has a slightly inwardly concave curve, and the gentle slope portion 313(X1) is provided in the vicinity of the blade leading edge portion 32 of the blade 3 and the back plate suction portion 5 of the back plate 1 and extends forward. The gentle slope portion 31(X1) can suppress turbulence generated by the blade and the airflow, and can suppress turbulence in the entire flow path, thereby achieving high efficiency and low noise. Likewise, the curved portion 321(X2) is also shaped to suppress air turbulence. Further, although the blade trailing edge portion 34 of the present embodiment is a straight line in the vertical direction, other shapes are also possible.

As shown in fig. 7, the vicinity 312 of the leading edge in the blade rotation direction on the back plate 1 side is a twisted shape Y1 (solid line), and the twisting direction is curved outward in the outer periphery in the vicinity of the back plate 1, that is: the sectional shape of A-A 'is curved more gently than the sectional shape of C-C' (broken line) at the center and twisted outward in the outer periphery. Similarly, the vicinity 331 of the leading edge portion of the blade 3 on the shroud 2 side in the blade rotation direction is also formed in a twisted shape Y2 (solid line), and the twisting direction is curved outward in the outer periphery in the vicinity of the shroud 2. When the numerical values of example 1 are used, for example, the vertical height of the blade 3 is 140mm, and if the radius of curvature R3 at the leading edge portion in the C-C 'sectional shape as a reference is 313.2mm in fig. 7, the radius of curvature R1 at the leading edge portion in the a-a' sectional shape is 333.2mm, and the distance a1 is about 4.9 mm. The radius of curvature R2 at the leading edge portion in the E-E' cross-sectional shape was 318.3mm, and the distance a2 was about 1.7 mm.

The blade entrance angle α is continuously reduced from the center (C-C') of the vertical width of the blade 3 to the back plate 1 and the shroud 2 by the twisted shapes Y1, Y2 of the

vicinities

312, 331 of the leading edge. When the inlet angle α is described with reference to fig. 8, the angle formed by the tangent line indicated by the chain line and the blade inscribed circle R in the central portion of the blade 3 (fig. 8), that is, the inlet angle α 1, is set, but by setting the vicinity of the leading edge portion to the twisted shapes Y1 and Y2, the entire blade leading edge portion (32) having the inlet angle α 2 is close to the inflow angle of air, and therefore, the inflow state of the air flow in the

vicinity

312 and 331 of the leading edge portion of the blade 3 is improved, and not only the turbulence generated by the collision between the blade and the air flow but also the turbulence of the entire flow path can be suppressed, and high efficiency and low noise can be achieved.

[ 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 can be kept as they are, and the blade width (Z) can be easily changed while maintaining high efficiency and low noise. Therefore, the centrifugal fan corresponding to the designed air volume can be designed and manufactured.

Here, embodiment 2 in which the vertical width of the impeller 4' is changed and the blade width is made to correspond to the amount of air blowing will be described with reference to fig. 9 and 10.

Fig. 9 is a perspective view of the impeller 4' of example 2, and as shown in fig. 10, the twisted shapes Y1 and Y2 near the leading edge of the blade 3 are the same as those of example 1, and the blowing efficiency is improved and the noise is reduced as compared with the conventional partially cylindrical blade. That is, when the vertical width of the blade 3 is changed, the vertical width Z of the band-shaped portion (the alternate long and short dash line C-C 'D-D') at the center of the blade 3 is expanded or contracted to expand or contract the entire vertical width Z, and the twisted shapes Y1 and Y2 existing on the back plate 1 side and the shroud 2 side may be maintained as they are.

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

With the above-described configuration, the centrifugal blower blade structure according to each of the embodiments is adopted, and the inlet angle of the blade is continuously reduced from the center portion in the blade width direction to the back plate and the shroud by the twisted shape of the blade leading edge portion, so that the inflow state of the airflow at the blade leading edge portion is improved, and not only the turbulence generated by the collision between the blade and the airflow but also the turbulence of the entire flow path can be suppressed, and high efficiency and low noise can be achieved.

Further, by extending the center portion in the blade width direction in parallel in a cylindrical shape in the width direction of the blade, it is possible to obtain the air blowing efficiency and the noise reduction effect even if the blade width is variable while maintaining the twisted shape portion of the blade effective for the high efficiency and the low noise. This makes it possible to very easily manufacture fans having the same impeller diameter and different air volumes while maintaining efficiency.

Further, since the vicinity of the connection portion between the leading edge portion of the blade and the back plate extends in a gentle slope, the inflow state of the airflow in the vicinity of the back plate of the leading edge of the blade can be further improved, and further high efficiency and noise reduction can be achieved.

It is to be noted that the present invention is not limited to the above-described embodiments, and the present invention is applicable to a blower of an air conditioner in the embodiments, but may be used as a single blower, for example.

Claims

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.