JP2000240590A - Multiblade forward fan - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a centrifugal multiblade forward fan of reduced noise used for the cooling of electronic equipment and the like, ventilation, air conditioning, pneumatic conveying and the like. SOLUTION: This fun comprises blades approximately radially disposed at constant intervals in the circumferential direction between a disc-shaped main board and an annular side board while longitudinally narrowed, and a casing capable of pivotting an impeller inside and blowing out the wind in the circumferential direction. The main blades 1a and the intermediate blades 1b are alternately disposed, the inner diameters of the main blades 1a and the intermediate blades 1b are gradually increased from the main board side toward the side board side, a blade outlet angle is β2 is over 100 deg., a point of inflection position blade angle β4 is below 70 deg., and a ratio of a main blade inner diameter D1 and a blade outer diameter D2 at the main board side is below 0.7. On this occasion, the number of intermediate blades between main blades are different from the adjacent one in the circumferential direction, further the blade inner diameters of the adjacent blades including the main blades and the intermediate blades are different in the circumferential direction, and a forward inducer with respect to the rotating direction, is attached to an axial front edge at the inner peripheral side of the blade.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a centrifugal multi-blade fan, and more particularly to a multi-blade forward fan. Such a fan is used for cooling electronic equipment, or for ventilation, air conditioning, pneumatic transportation, and the like.

[0002]

2. Description of the Related Art Japanese Unexamined Patent Publication No. Hei 8-284886 discloses that as the ratio between the inner and outer diameters of an impeller increases, the circumferential velocity V increases and the inflow angle α
It is described that when the pressure increases, the flow of the fluid in the flow path between the blades separates from the blade surface and noise is generated. For this reason,
In this publication, a centrifugal fan with blades discloses a disk, an annular plate disposed parallel and coaxial to the disk, and a circumferentially spaced interval between the disks. A plurality of wings radially arranged at a distance are provided, and the inner peripheral edge of the annular plate is positioned radially outward from the radially inner end of the wing.

[0003] Japanese Patent Application Laid-Open No. Hei 9-166098 has an impeller having a large number of radially oriented blades which are arranged at intervals in the circumferential direction. The blades have an outer peripheral portion and an inner peripheral portion of the impeller. Describes a multi-blade radial fan curved in the direction of rotation of the impeller.

A multi-blade blower fan is disclosed in
Japanese Patent Application Laid-Open No. 5-321891 discloses an example in which an intermediate blade is disposed in Japanese Patent Application Laid-Open No. 1-19691.

[0005]

In any of the conventional impellers, the impeller has a two-dimensional shape, and the side plate-side impeller has a smaller inner / outer diameter ratio D ₄ / D ₂ of 0.6 or less, so that the suction area S of the impeller is small. _{4 (= (π / 4)} D 4 2) is small.

[0006] A conventional multi-blade forward fan has an inner diameter D _{1 of} the blade.
Since the ratio (D ₁ / D ₂ ) between the diameter and the outer diameter D ₂ is small, if the number of blades is increased, the blade interval (blade pitch) on the inner circumferential side of the blade is narrow, and the effective flow path in the circumferential direction (rotation direction). Since the width is small and air is difficult to flow in, noise is generated by disturbance on the back side of the leading edge of the blade, and the disturbance is the product (Z ₁ × N) of the number of blades Z ₁ on the inner circumferential side of the blade and the rotation speed N (Hz). This method has a disadvantage in that an outstanding sound pressure (rotating sound) is generated and the noise is loud.

Further, in the conventional multi-blade forward fan, since the blades have a two-dimensional shape, the flow at the blade leading edge when viewed in the axial direction is as follows.
Because the inflow and the axial vane angle greatly differ,
Turbulence occurred on the back side of the leading edge of the blade.

Further, since the inner / outer diameter ratio D ₄ / D _{2 of the} side plate-side blades is small at 0.6 or less, the suction area S _{4 of the} impeller is small, and it is difficult to increase the air volume of the fan.

The present invention has been made to solve the above problems, and has a large suction area so that air can easily flow in.
It is another object of the present invention to provide a multi-blade forward fan with low noise.

[0010]

SUMMARY OF THE INVENTION The present invention is directed to a main blade and an intermediate blade which are longitudinally sandwiched between a disk-shaped main plate and an annular side plate facing the main plate, and which are arranged substantially radially at regular intervals in a circumferential direction. Are alternately arranged, and the inner diameters of the main blade and the intermediate blade become larger from the main plate side to the side plate side and are the same at the side plate. The blade outlet angle β ₂ is 100 ° or more, and the outer peripheral side blade and the inner peripheral side. blade angle beta ₄ is 70 ° position wings curvature inflection at the junction of the blade (the blade inflection point) or less, the ratio of the main plate side blade inner diameter D ₁ and the blade outer diameter D ₂ at the main plate side is 0. 7 An impeller having the following blades is characterized.

The present invention is further characterized by an impeller provided with a forwardly directed inducer in the rotational direction at the axially leading edge on the inner peripheral side of the blade.

The present invention specifically provides the following assistance.

According to the present invention, there is provided a disk-shaped main plate, an annular side plate opposed to the disk-shaped main plate, and substantially radially arranged circumferentially between the disk-shaped main plate and the annular side plate. A plurality of main blades having a blade inner diameter D ₁ , a blade outer diameter D _{2 at} a position, a blade inner diameter D _{4 at} a position inside the side plate, and a blade outer diameter D _{2 at} the position of the main plate are arranged between these main blades. , Blade inner diameter D ₃ , blade inner diameter D at the position of the side plate
₃ impeller and an intermediate blade, and journalled to the impeller, and a casing for blowing in the circumferential direction by introducing air from the side plate, the main blade and the intermediate blade defines an outer circumferential blade portion and the inner peripheral The main blade and the intermediate blade form a three-dimensional shape with the side blade portion, the main blade and the intermediate blade have a blade outlet angle β ₂ , and an angle β ₄ at a boundary between the outer peripheral side blade portion and the inner peripheral side blade portion. The blade has a blade entrance angle β ₁ , the middle blade has a blade entrance angle β ₃ , D ₁ / D ₂ <0.7, D ₁ <D ₃ <D ₄ β ₂ > 100 °, β ₁ <70. °, β ₄ <70 ° Provide a multi-blade forward fan.

[0014] The present invention further intermediate vanes are disposed with different number between adjacent main blades, the blade inlet angle beta ₃ of each intermediate blade provides a countercurrent fan before multiblade which is the same angle .

[0015] The present invention further intermediate vanes, a plurality of sheets arranged with different inner diameter between adjacent main blade, the inlet angle beta ₃ of small intermediate vanes having an inner diameter of the inlet angle of the large intermediate vane inner diameter beta Provides a multi-wing forward fan greater than _three .

The present invention further provides a multi-blade forward fan in which the main blade is provided with a forwardly directed inducer at the axially forward edge on the inner circumferential side of the blade.

The present invention further provides a multi-blade forward fan in which the intermediate blade is provided with a forwardly directed inducer in the rotational direction at an axially leading edge on the inner circumferential side of the blade.

According to the present invention, there is provided a disk-shaped main plate, an annular side plate opposed to the disk-shaped main plate, and substantially radially arranged circumferentially between the disk-shaped main plate and the annular side plate. A plurality of blades having a blade inner diameter D ₁ , a blade outer diameter D _{2 at} a position, and a blade inner diameter D _{4 at} a position inside the side plate, and a circle supporting the impeller and introducing air from the side plate side. The blade includes a casing that blows out in the circumferential direction. The blade has a three-dimensional shape with the outer peripheral blade portion and the inner peripheral blade portion. The blade entrance angle β ₁ , the blade exit angle β ₂ , and the outer peripheral blade portion and the inner peripheral side. It has an angle β ₄ at the boundary with the blade, D ₁ / D ₂ <0.7 β ₂ > 100 °, β ₁ <70 °, β ₄ <70 °, and the axial direction on the inner circumferential side of the blade. Provided is a multi-blade forward fan having a forwardly directed inducer at a leading edge in a rotational direction.

[0019]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a front view of an impeller of a multi-blade forward fan according to the present invention, FIG. 2 is a perspective view of a part of the impeller, and FIG.
FIG. 4 is a cross-sectional view taken along the line II in the direction of the rotation axis. FIG. 4 is a view showing the overall configuration of a multi-blade forward fan according to an embodiment.
FIG. 4 is a diagram showing a casing of a multi-blade forward fan.

In FIG. 1, the multi-blade forward fan is of a centrifugal type and comprises a main blade 1a and an intermediate blade 1b. One or two intermediate blades 1b are arranged between the main blades 1. The multi-blade forward fan rotates in the rotation direction 2 indicated by the arrow. The main blade 1a and the intermediate blade 1b are respectively composed of inner blades 11a and 11b and outer blades 12a and 12b.
b. The inner peripheral side blades 11a and 11b and the outer peripheral side blades 12a and 12b form circular arcs, respectively.
And 12a and 11b and 12b form two continuous arcs. Each was curvatures in different directions, the inner peripheral side blade part 11a, 11b has a radius of curvature _{R 1,} the outer peripheral side blade part 12a, and 12b with a radius of curvature _{R 2.} R ₁ includes an infinite diameter, and R ₁ is greater than R ₂ . The inlet end of the inner blade 11a extends long until the outlet end of the outer blade 12a is located outside the radius line having the intersection with the radius line from the center point of the multi-blade forward fan. .

FIG. 2 is a perspective view showing the main blade 1a and the intermediate blade 1b forming two arcs.

In FIG. 3, the impeller 3 has an annular side plate 5 and a main plate 6, and is sandwiched between these plates so that the blades 1 extend in the circumferential direction.
Are arranged almost radially.

[0024] In Figures 1 and 2, _{D 1} is the main plate side blade inner diameter, _{D 2} is the impeller outer diameter, _{D 3} is the outer peripheral side blade part 1
The main plate side inner diameter of b, D ₄ represents the inner diameter of the inside position of the side plates, beta ₁ vane inlet angle, beta ₂ vane outlet angle, beta intermediate vane inlet angle, beta inner vane portions 11a, 11b and outer vane Represents the continuation point with the parts 12a and 12b, that is, the inflection point blade angle.

In FIG. 3, a hub 12 is screwed to the main plate 6, and an inner diameter point 13 of the blade 1 is an intersection with the main plate 6. The outer diameter point 14 is an intersection with the inner position of the side plate 5, and the main blade 1a has a convex arc inlet shape that is bulged from the inner diameter point 13 to the outer diameter point 14. Intermediate blade 1
The intersection point b forms with the main plate 6 is indicated by 15, and has an arc entrance shape indicated by a dotted line. The hub 12 has a screw hole 16.

The main blade 1b can be formed such that the intersection 13 is located at the root of the hub 12 or at the tip thereof by making the boss 12 smaller and shorter.

As shown in FIG. 4, the multi-blade forward fan surrounds the impeller 3, a motor 10 whose rotary shaft is fitted in a hub 9 at the axial center of the impeller 3, and the periphery of the impeller 3. Casing 7
It is composed of The impeller 3 includes 36 or more annularly arranged blades 1, an annular side plate 5 for fixing the air suction side end in the longitudinal direction of each blade, and each blade 1 together with the side plate 5 facing the side plate 5. And a disk-shaped main plate 6 having a hub 9 at the center. The casing 7 has a large opening at one end on the air intake side, and the other end opposite to the opening surrounds the main plate 6 along the main plate 6. The motor 10 for driving the impeller 3 is attached so as to project outward from the casing 7 in a direction opposite to the impeller 3. The casing 7 has a spiral shape as shown in FIG. 5, and the flow 8 flowing from the opening is driven by the impeller 3 and flows around the impeller 3 from the periphery of the impeller 3 like the flows 8a and 8b. It flows out and exits as 8c from the outlet at the tip.

As shown in FIG. 1, the multi-blade impeller 3 has 36 or more main blades 1a and intermediate blades 1b arranged alternately in the circumferential direction, and both the main blades 1a and the intermediate blades 1b have a main plate 6a. And the side plate 5. The use of the intermediate blades has the characteristic that the area between the circumferential blades at the leading edge on the inner circumferential side of the main blades can be increased, and the air volume of the multi-blade fan is increased.

As shown in FIG. 3, the blade 1 has a three-dimensional shape in which the inner diameters of the main blade 1a and the intermediate blade 1b are different in diameter in the axial direction from the main plate 6 side to the side plate 5 side. the inner diameter of the main blade 1a at position _{D 1,} the inner diameter of the intermediate blade 1b is _{D 3 (D 1 <D 3} ), the main blade 1a in the side plate 5, each vane inner diameter of the intermediate blade 1b is _{D 4 (D} 1 _{<D 3} <
D ₄ ). As a result, the suction area S ₄ of the impeller 3 (=
(π / 4) D ₄ ² ) is increased, and the air volume of the fan is increased.

As shown in FIG. 1, the main blade 1a and the intermediate blade 1b each have a concave arcuate shape when the blade outer peripheral side is viewed from the front in the rotational direction.
The inner peripheral side is a convex arc, and the inner peripheral side and the outer peripheral side are connected smoothly. Main blade 1a, with intermediate vanes 1b, the outlet angle beta ₂ by the arc of the radius of curvature R ₂ at the outer peripheral side
It is formed and the inner peripheral side of the main blade 1a to form a vane inlet angle beta ₁ by the arc of radius of curvature R _1, the intermediate blade inlet angle by an arc of radius of curvature R ₁ at the inner circumferential side of the intermediate blade 1b beta
₃ is formed. The radius of curvature R ₂ and the radius of curvature R ₁ are smoothly connected, the diameter of the junction (blade inflection point) between the radius of curvature R ₂ and the radius of curvature R ₁ is D _4, and the blade angle at D ₄ is the blade entrance angle β. ₄ , the blade angle β ₄ of the present invention is 70 ° or less. Furthermore, the main blade inside diameter D ₁ and the ratio of the blade outer diameter of the main plate side was set to 0.7 or less.

As shown in FIG. 1, the impeller 3 has a blade outlet angle β ₂ of 100 ° or more to increase the work amount.
It faces forward in the direction of rotation. In order to allow air to smoothly flow in at the blade inlet, the respective blade inlet angles β ₁ and β ₃ of the main plate side blade inner diameter D ₁ , the main plate side inner diameter D _{3 of} the intermediate blade 1b, and the side plate side blade inner diameter D ₄ are the air inflow angles. To 70 ° or less. Generally, the relationship between the blade inlet diameter of a centrifugal fan and the air inflow angle is such that the larger the blade inlet diameter, the smaller the air inflow angle becomes, so that β ₁ > β _3.
> Β ₄ is ideal. In this embodiment, as shown in FIG. 1, the blade angle is set to 70 °> β ₁ and 70 °> β ₄ to form the blade. As a result, in the fan of the present embodiment, the turbulence generated on the back side of the blade front edge is greatly reduced, and the rotation noise (the product (Z ₁ ) of the number of inner peripheral blades Z ₁ and the rotational speed N (Hz) is obtained. XN), and the noise of the multi-blade forward fan can be reduced, for example, about 5d compared to the conventional multi-blade forward fan.
B noise can be reduced.

FIG. 6 shows a multi-blade forward fan according to another embodiment of the present invention. The multi-blade impeller 3 is provided with 36 or more main blades 1a and intermediate blades 1b, 1c in the circumferential direction so that the effective flow path width is large on the inner circumferential side of the blade and air can easily flow therein. It is fixed by the side plate 5, and the radial leading edge position of the blade is arranged at different radial positions on the adjacent blade. The blade shape is a concave curved shape on the outer peripheral side and a convex curved shape on the inner peripheral side when viewed from the front in the rotational direction of the blade,
Smoothly joined at the diameter of the diameter D _4, the vane inlet angle beta ₁ of the inner peripheral _side, β _3b, β _3c is not more than 70 ° in accordance with the inflow angle of air.

With the blades shown in FIG. 6, the periodicity of the number of blades is eliminated, and the predominantly generated predominant rotation noise is greatly reduced. As a result, this shape has the effect of reducing the noise of the multi-blade forward fan by about 3 dB.

FIG. 7 shows a multi-blade forward fan according to another embodiment of the present invention, in which the blades on the inner peripheral side are straight to improve manufacturability. Although the blade entrance angles β ₁ and β ₃ on the inner peripheral side are slightly smaller than those in FIG. 1, the flow state on the inner peripheral side of the blade is greatly improved as compared with the conventional multi-blade fan. The turbulence that has occurred is reduced, and the predominant rotation sound is also reduced.

FIG. 8 shows a multi-blade forward fan according to another embodiment of the present invention, in which a blade leading edge (inducer) 4a having a forward shape in the rotational direction is provided at an axial tip (side plate side) on the inner circumferential side of the blade. 9 is a front view of an impeller with an inducer, and FIG. 10 is a side view of the impeller with an inducer.
FIG. 11 shows a perspective view of a blade provided with an inducer.

In the multi-blade impeller 3, 36 or more main blades 1a and intermediate blades 1b are alternately arranged in the circumferential direction so that the effective flow path width is large on the inner peripheral side of the blade and air can easily flow in. , Main plate 6
And a side plate 5, a blade having an inducer 4 a attached to the inner peripheral side of the main blade 1 a and an inducer 4 b inserted into the inner peripheral side of the intermediate blade 1 b. The main blade 1 a and the intermediate blade 1 b are alternately arranged. It is in the form of being arranged.

In FIG. 8, for the inducer 4a,
When the axial flow velocity component of air is c, the peripheral speed of the blade is u, and the relative speed of air is w, the inflow angle of air is δ as shown in the figure.
_a next, in a juicer angle of the blade is a [delta] _b, [delta] _a
It is approximately [delta] _b.

As shown in FIG. 9, the impeller of the present invention has a concave arc shape on the outer peripheral side of the blade and a convex blade shape on the inner peripheral side of the blade when viewed from the front in the rotation direction, and both the main blade 1a and the intermediate blade 1b have the blade shape. A forward-facing inducer 4a is provided on the inner peripheral side at the axial end (side plate side). The relationship between the blade entrance angle β ₁ , the intermediate blade entrance angle β ₃ , the inflection point position blade angle β ₄ , and the like when the inner peripheral blade shape is convex is β ₁ <70 ° and β ₄ <70 °. As in the previous embodiment, D ₁ / D ₂ <0.7 and β ₂
> 100 °.

The turbulence at the leading edge of the blade is reduced by the blades of FIGS. 8, 9 and 10, and the predominant rotating noise that has conventionally occurred is greatly reduced. 8, 9, and 10 on the leading edge of the blade
When only the inducer 4a is attached, a noise reduction effect of about 2 dB can be obtained.

[0040]

According to the present invention, an impeller is constructed by alternately arranging main blades and intermediate blades of a multi-blade forward fan, and the inner diameters of the main blade and the intermediate blade fix each blade. It becomes larger from the main plate side to the side plate side and becomes the same at the side plate, the blade exit angle β ₂ is 100 ° or more, and the inflection point position blade angle β ₄
The 70 ° or less, the ratio of the main blade inside diameter D ₁ and the blade outer diameter D ₂ of the main plate side it is possible to reduce noise in those with 0.7 or less.

The number of intermediate blades between the main blades is made different in the circumferential direction, the inner diameters of the main blades and the adjacent blades including the intermediate blades are made different, and further, on the inner peripheral side of the main blades and the intermediate blades. By adopting a form in which a forward-shaped inducer 4a is attached to the axial end (side plate side), noise can be further reduced by about 5 dB as compared with a conventional multi-blade forward fan.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a blade of a multi-blade forward fan according to an embodiment of the present invention.

FIG. 2 is a perspective view showing one embodiment of an impeller.

FIG. 3 is a sectional view taken along line II of FIG. 1;

FIG. 4 is an overall configuration diagram of a multi-blade forward fan.

5 is a view taken in the direction of arrows II-II in FIG. 3;

FIG. 6 is a diagram showing a configuration of a multi-blade forward fan according to another embodiment.

FIG. 7 is a diagram showing a configuration of a multi-blade forward fan according to another embodiment.

FIG. 8 is an enlarged view of an inducer according to another embodiment.

FIG. 9 is a diagram showing a configuration of a multi-blade forward fan according to another embodiment.

FIG. 10 is a sectional view taken along line III-III of FIG. 9;

FIG. 11 is a perspective view showing an embodiment of an impeller having an inducer.

[Explanation of symbols]

1a: Main blade, 1b, 1c: Intermediate blade, 2: Rotation direction,
3 impeller, 4a, 4b inducer, 5 side plate, 6
... main plate, 7 ... casing, 8, 8a, 8b, 8c ... flow, 9 ... hub, 10 ... motor, c ... axial flow velocity component of the air, D 1 _... main plate side impeller inside diameter, D 2 _... impeller outside diameter, D
₃ ... 1b inner diameter on the main plate side, D _3b .
The main plate side inner diameter of _{3c ...} 1c, D 4 ... side plate impeller inside diameter,
D ₇ … inner diameter of casing, R ₁ … radius of curvature of inner peripheral side blade,
R ₂ : outer radius of curvature of blade, u: peripheral speed of blade, w: relative speed of air, β ₁ : blade inlet angle, β ₂ : blade outlet angle, β ₃ , β _3b , β _3c : intermediate blade inlet angle , Β ₄ …
Vane inlet angle, [delta] _{a ...} inflow angle of air, [delta] _{b ...} Inn juicer angle of the blade.

 ──────────────────────────────────────────────────の Continuing from the front page (72) Inventor Takayuki Shin 1st Horiyamashita, Hadano-shi, Kanagawa F-term, General-purpose Computer Division, Hitachi, Ltd. 3H033 AA02 AA11 BB02 BB06 CC01 DD04 DD09 DD12 DD19 DD23 DD27 EE06 EE19

Claims (6)

[Claims] 1. A disk-shaped main plate, an annular side plate opposed to the disk-shaped main plate, and substantially radially arranged in the circumferential direction between the disk-shaped main plate and the annular side plate, at a position of the main plate. A plurality of main blades having a blade inner diameter D ₁ , a blade outer diameter D ₂ , and a blade inner diameter D _{4 at} a position inside the side plate, and are arranged between these main blades, and a blade outer diameter D _{2 at} the position of the main plate, a blade. an inner diameter D _3, the impeller and an intermediate blade vane inner diameter D ₃ at the position of the side plate, and rotatably supports the impeller, and a casing for blowing in the circumferential direction by introducing air from the side plate, the main blade and The intermediate blade has a three-dimensional shape with the outer peripheral blade portion and the inner peripheral blade portion. The main blade and the intermediate blade have a blade outlet angle β ₂ , and a boundary between the outer peripheral blade portion and the inner peripheral blade portion. an angle beta _4, the main blade has a blade inlet angle beta _1, intermediate blades Has a vane inlet angle beta _3, and wherein the _{D 1 / D 2 <0.7,} D 1 <D 3 <D 4 β 2> 100 °, β 1 <70 °, a β ₄ <70 ° Multi-wing forward-looking fan. 2. The method of claim 1, the intermediate blade is disposed with different number between adjacent main blades, the blade inlet angle beta ₃ of each intermediate vane is characterized in that it is the same angle multi Tsubasa forward fan. 3. The method of claim 1, the intermediate blade are plural arranged with different inner diameter between adjacent main blade, the inlet angle beta ₃ of small intermediate blades of inner diameter,
Multiblade anterograde fan being greater than the inlet angle beta ₃ of large intermediate vane inner diameter. 4. The multi-blade forward fan according to claim 1, wherein the main blade is provided with a forwardly directed inducer in the rotational direction at an axially leading edge on the inner peripheral side of the blade. 5. The multi-blade forward fan according to claim 4, wherein the intermediate blade is provided with an inducer that is directed forward in the rotation direction at an axially leading edge on the inner circumferential side of the blade. 6. A disk-shaped main plate, an annular side plate opposed to the disk-shaped main plate, and substantially radially arranged in the circumferential direction between the disk-shaped main plate and the annular side plate, at a position of the main plate. An impeller having a blade inner diameter D ₁ , a blade outer diameter D ₂ , and a plurality of blades having a blade inner diameter D ₄ at an inner position of the side plate; and a shaft supporting the impeller and introducing air from a side plate side in a circumferential direction. The outer blade and the inner blade have a three-dimensional shape. The blade inlet angle β ₁ , the blade outlet angle β ₂ , the outer blade and the inner blade. And the angle β ₄ at the boundary with D ₁ / D ₂ <0.7 β ₂ > 100 °, β ₁ <70 °, β ₄ <70 °, and the axial leading edge on the inner circumferential side of the blade. A multi-blade forward fan characterized by comprising a forwardly directed inducer in the rotation direction.