WO2018189931A1 - Centrifugal fan, moulding die, and fluid feeding device - Google Patents

Abstract

This centrifugal fan (10) includes a front-side blade (21A) and a rear-side blade (21B). The shortest distance from any position on the top of a negative pressure surface of the front-side blade (2lA) to a positive pressure surface of the rear-side blade (21B) is referred to as the inter-blade distance. The position of the top of the negative pressure surface of the front-side blade (21A) in a maximum thickness portion is referred to as the maximum thickness position (P2). A range between the maximum thickness position (P2) and a front edge part (26) is referred to as an inner diameter-side negative pressure surface (24A). A range between the maximum thickness position (P2) and a rear edge part (27) is referred to as an outer diameter-side negative pressure surface (24B). The length from the front edge part to the rear edge part of the negative pressure surface of the front-side blade (21A) is referred to as the negative pressure surface length. The inter-blade distance at the inner diameter-side negative pressure surface is longer than that at the maximum thickness position. The inter-blade distance in a range in the outer diameter-side negative pressure surface between the maximum thickness position, and a position away from the maximum thickness position by a length equal to or greater than half of the negative pressure surface length, is substantially constant. Accordingly, separation of the flow from the blades is inhibited, and an improvement in performance and a reduction in noise can be achieved.

Description

Centrifugal fan, molding die and fluid feeder

This specification relates to a centrifugal fan, a molding die, and a fluid feeder. This application claims priority based on Japanese Patent Application No. 2017-0777580, which is a Japanese patent application filed on April 10, 2017. All the descriptions described in the Japanese patent application are incorporated herein by reference.

A plurality of blade bodies (wings) having the same size and the same shape may be arranged linearly or circularly at equal intervals and in the same posture. An aspect in which the plurality of blades are configured in this manner is called a blade row. There are two types of blade rows: a reduction blade row and a speed-up blade row.

Referring to FIG. 34, the deceleration blade row is for decelerating the flow and increasing the pressure, and is adopted for a compressor, a fan, a pump, and the like. In the reduction blade row shown in FIG. 34, a plurality of blades are arranged with a spacing D therebetween. Due to the expansion of the flow path, the speed is reduced from the speed WA to the speed WB, and the kinetic energy is effectively recovered as pressure (pressure increasing action). When the turning angle is θ and the angle formed by the blade row with respect to the normal of the flow is λ, in the pressure increasing action of the speed reducing blade row, for example, WA> WB and λ> θ / 2.

Referring to FIG. 35, on the other hand, the speed increasing cascade is for increasing the flow and lowering the pressure, and is adopted for a turbine, a windmill and the like. In the speed increasing cascade shown in FIG. 35, the speed is increased from the speed WA to the speed WB. In the speed increasing operation of the speed increasing cascade, for example, WA <WB and λ <θ / 2. In these blade rows, when the relationship of the following equation (1) is established and the pressure loss does not substantially occur, the pressure change amount is expressed by the following equation (2).
WB / WA = cosλ / cos (θ−λ) (1)
P2−P1 = ρ (WA ² −WB ² ) / 2 Formula (2)
As disclosed in the following Patent Documents 1 and 2, a centrifugal fan is known. A centrifugal fan generally becomes a speed reducing cascade due to its operating principle. Specifically, in the centrifugal fan, a plurality of blades are provided in a circle at regular intervals. Along with the rotation of the fan, a flow flows in from the vicinity of the rotation center, and a flow flows out from the outer periphery of the fan. The length in the circumferential direction increases proportionally as the distance from the center of rotation increases (the diameter increases). A flow path formed between adjacent blades (that is, between blades) gradually increases from the center of the fan toward the outside in the radial direction.

When the flow path is enlarged, the flow velocity of the flow flowing through the flow path is reduced in inverse proportion to the expansion of the flow path (the law of conservation of mass). Accordingly, the plurality of blades in the centrifugal fan generally form a speed reducing blade row. Conventionally used blades for centrifugal fans include arc blades, flat blades, airfoils, and the like. Centrifugal fans using these general blades as blade rows are reduced blade rows for the above reasons.

Japanese Patent No. 5469635 JP 2005-016315 A

The flow velocity of the flow that flows between the blades of the centrifugal fan decreases as the flow goes radially outward. The kinetic energy of the flow decreases in proportion to the square of the decrease in flow velocity. When the kinetic energy of the flow is lost with respect to the negative pressure acting on the blade body, the flow is separated from the blade body, so that the performance as the blade body is lowered and noise is increased. Many of the conventional blades used in centrifugal fans have a shape and size mainly intended to overcome high-pressure loss, and as a result, they tend to cause flow separation and increased noise. It was.

The present specification relates to a centrifugal fan capable of improving performance and reducing noise by suppressing separation of a flow from a blade body, a molding die used for manufacturing the centrifugal fan, and the centrifugal fan. Disclosed is a fluid feeder.

The centrifugal fan according to the first aspect of the present disclosure includes a plurality of blade bodies that have a front edge portion into which air flows and a rear edge portion from which air flows out, and are provided at intervals from each other in the circumferential direction. Each of the plurality of blade bodies extends between the front edge portion and the rear edge portion, and has a positive pressure surface positioned on the rotation direction side of the blade body, and the rotation direction of the blade body. A blade surface composed of a suction surface positioned on the opposite side is formed, and the plurality of blade bodies are opposed to the front blade body and the front blade body with the space therebetween and in a rotational direction with respect to the front blade body The shortest distance from any location on the suction surface of the front blade body to the pressure surface of the rear blade body is defined as the inter-blade distance at the above location. The front blade body is the maximum thickness of the front blade body. A position on the suction surface in the maximum thickness portion is defined as a maximum thickness position, and the maximum thickness position of the suction surface of the front blade body and the front edge portion. Is defined as the inner diameter side suction surface, the range between the maximum thickness position and the rear edge of the suction surface of the front blade body is defined as the outer diameter side suction surface, Supposing that the length from the leading edge portion to the trailing edge portion on the suction surface of the front blade body is defined as the suction surface length, the distance between the blades on the inner diameter side suction surface is the blade at the maximum thickness position. The distance between the blades in the range between the maximum thickness position of the outer diameter-side suction surface and a position separated from the maximum thickness position by at least half of the suction surface length. The distance is substantially constant.

The centrifugal fan according to the second aspect of the present disclosure includes a plurality of blade bodies that have a front edge portion into which air flows and a rear edge portion from which air flows out, and are provided at intervals from each other in the circumferential direction. Each of the plurality of blade bodies extends between the front edge portion and the rear edge portion, and has a positive pressure surface positioned on the rotation direction side of the blade body, and the rotation direction of the blade body. A blade surface composed of a suction surface located on the opposite side is formed, and each of the plurality of blade bodies is located on the radially outer side of the inner diameter side blade portion including the front edge portion and the inner diameter side blade portion, An outer diameter side blade portion including the rear edge portion, and the inner diameter side blade portion is a maximum thickness portion defining the maximum thickness of the inner diameter side blade portion, the front edge portion, and the The blade thickness gradually increases from the leading edge side toward the radially outer side. An enlarged portion and a reduced portion that is located radially outward from the maximum thickness portion and gradually decreases in blade thickness from the maximum thickness portion side toward the radial outer side, and the inner diameter blade portion Both the suction surface and the pressure surface of the inner diameter blade portion have a surface shape that curves convexly toward the opposite side of the rotation direction, and the curvature of the suction surface of the inner diameter blade portion is Larger than the curvature of the pressure surface of the inner diameter blade portion, the outer diameter blade portion includes a plate-like portion extending from the rear edge side to the radially inner side with substantially the same blade thickness, The curvature of the suction surface of the portion and the curvature of the pressure surface of the plate-like portion are both smaller than the curvature of the suction surface of the inner diameter blade portion.

In the centrifugal fan, the positive pressure surface of the inner diameter side blade portion and the positive pressure surface of the outer diameter side blade portion are tangent to each other, and the negative pressure surface of the inner diameter side blade portion and the negative pressure surface of the outer diameter side blade portion And may be tangent to each other.

In the centrifugal fan, the maximum thickness of the outer diameter side blade portion is smaller than the maximum thickness of the inner diameter side blade portion, and the warpage of the outer diameter side blade portion is smaller than the warpage of the inner diameter side blade portion. Also good.

In the centrifugal fan, the inner diameter blade portion is provided with a through hole extending in a direction parallel to the rotation axis, and the through hole is formed to include the maximum thickness portion, Or you may form one each in the radial direction inner side and radial direction outer side of the said maximum thickness part.

In the centrifugal fan, when the inner peripheral surface forming the through hole in the inner diameter blade portion is viewed from a direction parallel to the rotation axis, the inner peripheral surface has a crescent shape. May be.

In the centrifugal fan, a straight line connecting the leading edge portion and the trailing edge portion is defined as a chord line, a length of the chord line is C, and the chord line extends from the suction surface of the blade body to the chord line. On the other hand, when the length of the perpendicular at the position where the length of the perpendicular drawn down is the maximum is t, and the value of t / C is defined as a warp ratio m, each of the plurality of blade bodies has a warp ratio m of It may be formed to be 0.25 or more.

In the centrifugal fan, the plurality of blade bodies may be configured to form a constant velocity blade row.

The centrifugal fan may be formed of a resin.
The molding die based on the present disclosure is used to mold the centrifugal fan based on the present disclosure.

A fluid feeder based on the present disclosure includes a blower configured by the centrifugal fan based on the present disclosure and a drive motor connected to the centrifugal fan and rotating the plurality of blade bodies.

According to the centrifugal fan having the above-described configuration, the flow path between the blade bodies adjacent to each other in the rotation direction extends with a substantially constant flow path cross-sectional area from the center side of the centrifugal fan toward the radially outer side. The flow velocity of the flow formed between the blade bodies adjacent to each other in the rotation direction can be kept substantially constant even if the flow proceeds from the center side of the centrifugal fan to the radially outer side. Even if the flow travels radially outward, it is possible to suppress a decrease in the flow velocity, and it is also possible to suppress a decrease in the kinetic energy of the flow. This makes it possible to significantly increase the time and distance margins until the kinetic energy of the flow is lost with respect to the negative pressure acting on the blades. It is also possible to suppress the separation of the flow from the blade body. As a result, it is possible to suppress the performance as the blade body from being lowered, and it is possible to greatly reduce the occurrence of noise by suppressing the separation. .

1 is a perspective view showing a centrifugal fan 10 according to Embodiment 1. FIG. 1 is a front view showing a centrifugal fan 10 according to Embodiment 1. FIG. It is a front view which expands and shows the area | region enclosed by the III line | wire in FIG. It is a front view which expands and shows a part of centrifugal fan 10 shown in FIG. It is a front view which shows the centrifugal fan 10A in Embodiment 2. FIG. It is a front view which expands and shows the area | region enclosed by VI line | wire in FIG. It is a front view which expands and shows a part (blade body 21) of the centrifugal fan 10A shown in FIG. It is a perspective view which shows the centrifugal fan 10B in Embodiment 3. FIG. It is a front view which expands and shows a part (blade body 21) of the centrifugal fan 10B shown in FIG. It is a front view which expands and shows a part (blade body 21) of the centrifugal fan 10C in the modification of Embodiment 3. FIG. It is a front view which expands and shows a part (blade body 21) of centrifugal fan 10D in Embodiment 4. FIG. It is a front view which expands and shows a part (blade body 21) of the centrifugal fan 10E in the 1st modification of Embodiment 4. FIG. It is a front view which expands and shows a part (blade body 21) of the centrifugal fan 10F in the 2nd modification of Embodiment 4. FIG. FIG. 10 is a cross-sectional view showing a molding die 110 used at the time of manufacturing the centrifugal fan 10 with respect to the fifth embodiment. FIG. 10 is a cross-sectional view showing a blower 120 using a centrifugal fan 10 with respect to the fifth embodiment. FIG. 16 is a cross-sectional view showing a cross-sectional shape of the blower 120 along the line XVI-XVI in FIG. 15. FIG. 10 is a cross-sectional view showing an air cleaner 140 using a centrifugal fan 10 with respect to the fifth embodiment. It is a front view which expands and shows a part (blade body 21) of the centrifugal fan regarding an experiment example. It is a table | surface which shows the experimental condition and experimental result regarding an experiment example. It is a front view which expands and shows a part (blade body 21) of centrifugal fan 10S1 of Experimental example 1. FIG. It is a front view which expands and shows a part (blade body 21) of centrifugal fan 10S5 of Experimental example 5. FIG. It is a front view which expands and shows a part (blade body 21) of centrifugal fan 10S9 of Experimental example 9. FIG. It is a graph which shows the relationship between curvature ratio m and an air volume as an experimental result regarding an experiment example. It is a graph which shows the relationship between curvature ratio m and noise as an experimental result regarding an experimental example. It is a graph which shows the relationship between curvature ratio m and power consumption as an experimental result regarding an experiment example. It is a graph which shows the relationship between the maximum blade thickness and an air volume as an experimental result regarding an experimental example. It is a graph which shows the relationship between the maximum blade thickness and noise as an experimental result regarding an experimental example. It is a graph which shows the relationship between the maximum blade thickness and power consumption as an experimental result regarding an experimental example. It is a graph which shows the relationship between blade thickness ratio and an air volume as an experimental result regarding an experiment example. It is a graph which shows the relationship between blade thickness ratio and a noise as an experimental result regarding an experimental example. It is a graph which shows the relationship between blade thickness ratio and power consumption as an experimental result regarding an experiment example. It is a front view which expands and shows a part (blade body 21) of centrifugal fan 10S7 based on Experimental example 7. FIG. It is a front view which expands and shows a part (blade body 21) of centrifugal fan 10S7a regarding Experimental example 7. FIG. It is sectional drawing which shows the several blade body comprised so that the speed-reduction blade row | line | column may be made. It is sectional drawing which shows the several blade body comprised so that the speed-increasing blade row | line | column may be made.

Embodiments will be described below with reference to the drawings. The same parts and corresponding parts are denoted by the same reference numerals, and redundant description may not be repeated.

[Embodiment 1]
The centrifugal fan 10 according to the first embodiment will be described with reference to FIGS. 1 and 2 are a perspective view and a front view showing the centrifugal fan 10, respectively. Referring to FIGS. 1 and 2, centrifugal fan 10 has a plurality of blade bodies 21. The centrifugal fan 10 has a substantially cylindrical appearance as a whole, and the plurality of blade bodies 21 are arranged on the side surfaces of the substantially cylindrical shape. Centrifugal fan 10 is integrally formed of resin, and rotates in the direction indicated by arrow 103 about virtual rotation shaft 101.

Centrifugal fan 10 sends air taken from the inner periphery side to the outer periphery side by a plurality of rotating blade bodies 21. Centrifugal fan 10 sends out air radially outward from the center of rotation using centrifugal force. Centrifugal fan 10 functions as a sirocco fan, is mounted on household electrical equipment and the like, and can be used at a rotational speed in a low lay nozzle number region.

The centrifugal fan 10 further has outer peripheral frames 12 and 13. The outer peripheral frames 12 and 13 are formed to extend in an annular shape centering on the rotation shaft 101. The outer peripheral frames 12 and 13 are arranged at a distance in the axial direction of the rotating shaft 101. The outer peripheral frame 13 is integrally formed with a boss portion 16 for connecting the centrifugal fan 10 to a drive motor. The boss part 16 is composed of, for example, a rubber part and a metal part, and is integrated with the outer peripheral frame 13 by insert molding.

The plurality of blade bodies 21 are provided at intervals from each other in the circumferential direction around the rotation shaft 101. The plurality of blade bodies 21 are arranged at equal intervals in the circumferential direction around the rotation shaft 101, and are supported by the outer peripheral frame 12 and the outer peripheral frame 13 at both ends in the axial direction of the rotation shaft 101. The blade body 21 is erected on the outer peripheral frame 13 and is formed to extend along the axial direction of the rotary shaft 101 toward the outer peripheral frame 12.

FIG. 3 is an enlarged front view showing a region surrounded by line III in FIG. 2, and FIG. 4 is an enlarged front view showing a part of the centrifugal fan 10 shown in FIG. 3 and 4 show the shape of the blade body 21 when viewed from a direction parallel to the rotating shaft 101 (FIGS. 1 and 2) of the centrifugal fan 10.

As shown in FIGS. 3 and 4, the plurality of blades 21 have the same shape. Each of the plurality of blade bodies 21 is formed to have the same blade cross-sectional shape even when cut at any position in the axial direction of the rotating shaft 101.

The blade body 21 is located at the end portion on the inner peripheral side of the blade body 21 and is positioned at the front edge portion 26 into which air flows during rotation and the end portion on the outer periphery side of the blade body 21, and air flows out during rotation. And a trailing edge 27. The blade body 21 is formed so as to be inclined in the circumferential direction around the rotation shaft 101 from the front edge portion 26 toward the rear edge portion 27. The blade body 21 is formed to be inclined in the rotation direction of the centrifugal fan 10 from the front edge portion 26 toward the rear edge portion 27.

A blade surface 23 including a pressure surface 25 and a suction surface 24 is formed on the blade body 21. The positive pressure surface 25 extends between the front edge portion 26 and the rear edge portion 27 and is located on the rotational direction side of the blade body 21. The negative pressure surface 24 extends between the front edge portion 26 and the rear edge portion 27, and is located on the opposite side of the blade body 21 in the rotational direction (the back side of the positive pressure surface 25). When the centrifugal fan 10 rotates, a pressure distribution that is relatively large on the positive pressure surface 25 and relatively small on the negative pressure surface 24 is generated as an air flow is generated on the blade surface 23.

The plurality of blade bodies 21 include a front blade body 21A and a rear blade body 21B. The front blade body 21A and the rear blade body 21B have the same shape and size. The rear blade body 21B is opposed to the front blade body 21A with a space therebetween, and is positioned on the opposite side of the rotation direction (arrow 103) with respect to the front blade body 21A.

From an arbitrary location on the negative pressure surface 24 (a portion surrounded by a dotted line 24R in FIG. 4) of the front blade body 21A to a positive pressure surface 25 (a portion surrounded by a dotted line 25R in FIG. 4) of the rear blade body 21B. The shortest distance is defined as the distance between the blades at this arbitrary point. For example, interblade distances L1 to L6 are defined at locations P1 to P6 on the suction surface 24 of the front blade body 21A, respectively.

The front blade body 21A has a maximum thickness portion (a portion indicated by an arrow H) that defines the maximum thickness of the front blade body 21A. The maximum thickness portion means that when a circle having the largest size among the circles inscribed in the suction surface 24 and the pressure surface 25 is drawn between the suction surface 24 and the pressure surface 25, the inscribed circle and the negative surface are negative. An intersection point with the pressure surface 24 and an intersection point between the inscribed circle and the positive pressure surface 25 are defined, and a maximum thickness portion is defined so as to include these two intersection points. The location P2 corresponds to a position on the suction surface 24 in the maximum thickness portion (hereinafter referred to as the maximum thickness position P2).

The range between the maximum thickness position P2 and the front edge portion 26 in the suction surface 24 of the front blade body 21A is defined as the inner diameter side suction surface 24A. A range between the maximum thickness position P2 and the rear edge 27 in the suction surface 24 of the front blade body 21A is defined as an outer diameter-side suction surface 24B. Furthermore, the length from the front edge portion 26 to the rear edge portion 27 in the suction surface 24 of the front blade body 21A (the length of the portion surrounded by the dotted line 24R in FIG. 4) is defined as the suction surface length 24L. The negative pressure surface length 24L is a total value of the length of the inner diameter side negative pressure surface 24A and the outer diameter side negative pressure surface 24B.

In the centrifugal fan 10 of the present embodiment, the interblade distance on the inner diameter side negative pressure surface 24A is configured to be longer than the interblade distance L2 at the maximum thickness position P2. The inter-blade distance L1 at an arbitrary point P1 between the maximum thickness position P2 and the leading edge portion 26 is configured to be longer than the inter-blade distance L2 at the maximum thickness position P2. In this Embodiment, it is comprised so that the distance between blades may become long gradually as it approaches the front-edge part 26 from the largest thickness position P2.

In the outer diameter side negative pressure surface 24B, the inter-blade distance in a range between the maximum thickness position P2 and a position away from the maximum thickness position P2 by more than half of the negative pressure surface length 24L is substantially constant. Configured as follows. “Substantially constant” means that the distance between the blades is at least within a range of ± 25% of the distance L2 between the blades at the maximum thickness position P2, and more preferably the distance between the blades is the maximum thickness position P2. Is included in a range within ± 15% of the inter-blade distance L2, and more preferably, the inter-blade distance is included in a range within ± 10% of the inter-blade distance L2 at the maximum thickness position P2. Means that

In the centrifugal fan 10 of the present embodiment, the inter-blade distance L2 at the maximum thickness position P2, the inter-blade distance L3 at the location P3, and the inter-blade distance L4 at the location P4 are the same value. In the range between the place P4 and the place P5 in the outer diameter side negative pressure surface 24B, the distance between the blades gradually decreases from the place P4 to the place P5. The inter-blade distance L5 at the location P5 and the inter-blade distance L6 at the location P6 are the same value.

For example, the suction surface length 24L is 28.3 mm, the inter-blade distance (L2 to L4) at the maximum thickness position P2 and the places P3 and P4 is 3.6 mm, and the inter-blade distance at the places P5 and P6. The distance (L5, L6) is 3.4 mm. The distance between the blades in the range between the maximum thickness position P2 and the position away from the maximum thickness position P2 by the length of 21.4 mm toward the rear edge 27 is substantially constant.

(Function and effect)
When the centrifugal fan 10 is rotated, an air flow that flows in from the front edge portion 26, passes through the blade surface 23, and flows out from the rear edge portion 27 is generated as indicated by an arrow 102 in FIG. 1. Centrifugal fan 10 of the present embodiment includes a plurality of blade bodies 21 that satisfy the inter-blade distance as described above. The flow path between the blade bodies 21 adjacent to each other in the rotation direction is formed to extend with a substantially constant flow path cross-sectional area from the center side of the centrifugal fan 10 toward the radially outer side. Even if the flow proceeds from the central side of the centrifugal fan 10 to the outside in the radial direction, the flow velocity of the flow flowing between the blade bodies 21 adjacent to each other in the rotation direction can always be substantially constant.

The plurality of blade bodies 21 in the present embodiment constitute a constant velocity blade row different from the speed reduction blade row and the speed increasing blade row. Even if the flow travels radially outward, it is possible to suppress a decrease in the flow velocity, and it is also possible to suppress a decrease in the kinetic energy of the flow. This makes it possible to significantly increase the time and distance margins until the kinetic energy of the flow is lost with respect to the negative pressure acting on the blade body 21. It is also possible to suppress the flow from separating from the blade body 21, and as a result, it is possible to suppress the performance as the blade body 21 from being lowered, and it is possible to greatly reduce the occurrence of noise by suppressing the separation. It becomes.

[Embodiment 2]
A centrifugal fan 10A according to the second embodiment will be described with reference to FIGS. FIG. 5 is a front view showing the centrifugal fan 10A. 6 is an enlarged front view showing a region surrounded by the VI line in FIG. 5, and FIG. 7 is an enlarged view of a part (blade body 21) of the centrifugal fan 10A shown in FIG. It is a front view.

As shown in FIG. 5, the centrifugal fan 10A according to the second embodiment also has a substantially cylindrical appearance as a whole, similarly to the centrifugal fan 10 according to the first embodiment (FIG. 2). It is arrange | positioned at the substantially cylindrical side surface. Centrifugal fan 10 </ b> A is integrally formed of resin and rotates in a direction indicated by arrow 103 about virtual rotation shaft 101. Centrifugal fan 10 in the first embodiment and centrifugal fan 10A in the second embodiment are different in the following points.

6 and 7, each of the plurality of blade bodies 21 has an inner diameter side blade portion 21M including a front edge portion 26 and an outer diameter side blade portion 21N including a rear edge portion 27. The outer diameter side blade portion 21N is located on the radially outer side of the inner diameter side blade portion 21M. The inner diameter side blade portion 21M of the present embodiment is a portion of the blade body 21 surrounded by the front edge portion 26 and the points P10 to P12.

The inner diameter blade portion 21M includes a maximum thickness portion 21Ma, an enlarged portion 21Mb, and a reduced portion 21Mc. The maximum thickness portion 21Ma is a portion that defines the maximum thickness h2 in the inner diameter side blade portion 21M. The maximum thickness h2 is, for example, 3.6 mm. A point P11 indicates a position on the suction surface 24 in the maximum thickness portion 21Ma.

The enlarged portion 21Mb is a portion that is located closer to the front edge portion 26 than the maximum thickness portion 21Ma of the inner diameter side blade portion 21M. The enlarged portion 21Mb is located between the front edge portion 26 and the maximum thickness portion 21Ma, and the blade thickness h1 (FIG. 6) of the enlarged portion 21Mb gradually increases from the front edge portion 26 side toward the radially outer side. It is comprised so that it may become.

The reduced portion 21Mc is a portion located on the radially outer side than the maximum thickness portion 21Ma of the inner diameter side blade portion 21M. The reduced portion 21Mc is located between the maximum thickness portion 21Ma and the outer diameter side blade portion 21N, and the blade thicknesses h3 and h4 of the reduced portion 21Mc gradually become thinner from the maximum thickness portion 21Ma side toward the radial outer side. It is comprised so that it may become.

Each of the negative pressure surface 24M of the inner diameter side blade portion 21M and the positive pressure surface 25M of the inner diameter side blade portion 21M has a surface shape that curves in a convex shape toward the opposite side of the rotation direction (arrow 103 shown in FIG. 6). Yes. The curvature of the suction surface 24M of the inner diameter blade portion 21M is larger than the curvature of the positive pressure surface 25M of the inner diameter blade portion 21M.

The outer diameter side blade portion 21N includes a plate-shaped portion 21Np extending from the rear edge portion 27 side to the radially inner side with substantially the same blade thickness h6, h5 (FIG. 6). The blade thicknesses h6 and h5 are, for example, 1.0 mm. The curvature of the negative pressure surface 24Np of the plate-like portion 21Np and the curvature of the positive pressure surface 25Np of the plate-like portion 21Np are both smaller than the curvature of the negative pressure surface 24M of the inner diameter blade portion 21M.

(Function and effect)
When the centrifugal fan 10A is rotated, an air flow that flows in from the front edge portion 26, passes through the blade surface 23, and flows out from the rear edge portion 27 is generated. Centrifugal fan 10A of the present embodiment includes a plurality of blade bodies 21 that satisfy the blade thickness and curvature as described above. The flow path between the blade bodies 21 adjacent to each other in the rotation direction is formed so as to extend with a substantially constant flow path cross-sectional area from the central side of the centrifugal fan 10A toward the radially outer side. Even when the flow proceeds from the center side of the centrifugal fan 10A to the radially outer side, the flow velocity between the blade bodies 21 adjacent to each other in the rotation direction can be kept substantially constant.

The plurality of blade bodies 21 in the present embodiment also constitute a constant velocity blade row different from the speed reduction blade row and the speed increasing blade row. Even if the flow travels radially outward, it is possible to suppress a decrease in the flow velocity, and it is also possible to suppress a decrease in the kinetic energy of the flow. This makes it possible to significantly increase the time and distance margins until the kinetic energy of the flow is lost with respect to the negative pressure acting on the blade body 21. It is also possible to suppress the flow from separating from the blade body 21, and as a result, it is possible to suppress the performance as the blade body 21 from being lowered, and it is possible to greatly reduce the occurrence of noise by suppressing the separation. It becomes.

[First Modification of Second Embodiment]
Referring to FIG. 7, as a preferred embodiment, the pressure surface of inner diameter side blade portion 21M and the pressure surface of outer diameter side blade portion 21N are tangent to each other at point P10 and are smoothly connected. The suction surface of the side blade portion 21M and the suction surface of the outer diameter side blade portion 21N are preferably tangent to each other and smoothly connected at the point P12. According to this configuration, when air flows between adjacent blade bodies 21 in the rotation direction, lift is effectively generated in the flow of air, thereby further improving the performance as the blade body 21. .

[Second Modification of Embodiment 2]
Referring to FIG. 7, as a preferred embodiment, the maximum thickness of outer diameter side blade portion 21N is preferably smaller than the maximum thickness of inner diameter side blade portion 21M. Furthermore, the warp t2 of the outer diameter side blade portion 21N is preferably smaller than the warp t1 of the inner diameter side blade portion 21M. The warp t2 of the outer diameter side blade portion 21N and the warp t1 of the inner diameter side blade portion 21M are values defined as follows. The point P10 is located between the positive pressure surface of the inner diameter side blade portion 21M and the positive pressure surface of the outer diameter side blade portion 21N in the positive pressure surface 25 of the blade body 21.

A position where the straight line LN1 connecting the leading edge portion 26 and the point P10 in the inner diameter blade portion 21M is drawn, and the length of the perpendicular drawn from the suction surface in the inner diameter blade portion 21M to the straight line LN1 is maximized (point P11). Is defined as the warp t1 of the inner diameter blade portion 21M. A straight line LN2 connecting the point P10 and the trailing edge 27 in the outer diameter side blade portion 21N is drawn, and the perpendicular at the position P13 where the length of the perpendicular line drawn from the suction surface in the outer diameter side blade portion 21N to the straight line LN2 is the maximum is drawn. The length of W2 is defined as the warp t2 of the outer diameter side blade portion 21N.

According to the above configuration, when air flows between adjacent blade bodies 21 in the rotation direction, lift is effectively generated in the air flow, thereby further improving the performance of the blade body 21. . It is also possible to suppress the flow from separating from the blade body 21, and as a result, it is possible to suppress the performance as the blade body 21 from being lowered, and it is possible to greatly reduce the occurrence of noise by suppressing the separation. It becomes.

[Embodiment 3]
With reference to FIG. 8 and FIG. 9, the centrifugal fan 10B in Embodiment 3 is demonstrated. FIG. 8 is a perspective view showing the centrifugal fan 10B. FIG. 9 is an enlarged front view showing a part (blade body 21) of the centrifugal fan 10B shown in FIG.

As shown in FIG. 8, the centrifugal fan 10B in the third embodiment also has a substantially cylindrical appearance as a whole, similar to the centrifugal fans 10 (FIG. 2) and 10A (FIG. 5) in the first and second embodiments. A plurality of blades 21 are arranged on the substantially cylindrical side surface. Centrifugal fan 10B is integrally formed of resin, and rotates in the direction indicated by arrow 103 about virtual rotation shaft 101 (FIG. 8). Centrifugal fan 10A (FIG. 5) in the second embodiment is different from centrifugal fan 10B (FIGS. 8 and 9) in the third embodiment in the following points.

In the centrifugal fan 10B, a through hole 29 is provided in the inner diameter blade portion 21M (FIG. 9). The through hole 29 is formed so as to include the maximum thickness portion 21Ma of the inner diameter blade portion 21M, and extends in a direction parallel to the rotation shaft 101 of the centrifugal fan 10B.

According to the above-described configuration, the weight of the blade body 21 can be reduced, and sink marks during molding that can occur in the thick portion of the blade body 21 (near the maximum thickness portion 21Ma) can be reduced or reduced. . In addition, imbalance that occurs when the centrifugal fan 10B rotates can be significantly suppressed, and vibration noise of the centrifugal fan 10B can be reduced.

[Modification of Embodiment 3]
FIG. 10 is an enlarged front view showing a part (blade body 21) of centrifugal fan 10C according to a modification of the third embodiment. In the centrifugal fan 10C, a total of two through holes 29A and 29B are formed in the inner diameter blade portion 21M. The through holes 29A and 29B extend in a direction parallel to the rotation axis of the centrifugal fan 10C. The through holes 29A and 29B are formed one by one on the radially inner side and on the radially outer side of the maximum thickness portion 21Ma of the inner diameter blade portion 21M.

According to the above configuration, the weight of the blade body 21 can be further reduced, and the sink marks at the time of molding that can occur in the thick portion of the blade body 21 (near the maximum thickness portion 21Ma) are further reduced or reduced. It becomes possible. Moreover, the imbalance that occurs when the centrifugal fan 10C rotates can be significantly suppressed, and the vibration noise of the centrifugal fan 10C can be further reduced.

[Other configurations of the first and third embodiments]
In the above-described third embodiment (FIG. 9) and its modification (FIG. 10), the inner peripheral surface forming the through holes 29, 29 </ b> A, 29 </ b> B of the inner diameter blade portion 21 </ b> M When viewed from a parallel direction, the inner peripheral surface has a circular shape.

As shown in FIGS. 3 and 4 in the first embodiment without being limited to such a configuration, the inner peripheral surface forming the through hole 29 in the inner diameter blade portion 21M is parallel to the rotation shaft 101. When viewed from the direction, the inner peripheral surface may have a crescent shape. The crescent-shaped through-hole 29 can provide the effects and effects described in the description of the third embodiment and the modifications thereof, and can also be expected to improve the aesthetics as a centrifugal fan.

[Embodiment 4]
With reference to FIG. 11, centrifugal fan 10D in the fourth embodiment will be described. FIG. 11 is an enlarged front view showing a part (blade body 21) of the centrifugal fan 10D.

The centrifugal fan 10D according to the fourth embodiment and the centrifugal fans according to the first to third embodiments are such that, in the centrifugal fan 10D, a concave notch 29C is formed instead of the through hole 29 (through holes 29A, 29B). Is different. The notch 29 </ b> C extends from the portion near the outer diameter blade 21 </ b> N in the longitudinal direction of the pressure surface 25 of the inner diameter blade 21 </ b> M so as to approach the front edge 26. It is different from the configuration.

Even with the above-described configuration, the weight of the blade body 21 can be further reduced, and the sink marks at the time of molding that may occur in the thick portion of the blade body 21 (near the maximum thickness portion 21Ma) are further reduced or reduced. Is possible. In addition, imbalance that occurs when the centrifugal fan 10D rotates can be significantly suppressed, and vibration noise of the centrifugal fan 10D can be further reduced.

[First Modification of Embodiment 4]
With reference to FIG. 12, a centrifugal fan 10E according to a first modification of the fourth embodiment will be described. FIG. 12 is an enlarged front view showing a part (blade body 21) of the centrifugal fan 10E.

The centrifugal fan 10E (FIG. 12) in the present embodiment and the centrifugal fan 10D (FIG. 11) in the fourth embodiment are such that the notch 29C in the centrifugal fan 10E is in the longitudinal direction of the positive pressure surface 25 of the inner diameter blade portion 21M. It is different in that it includes a portion 29C1 extending so as to approach the front edge portion 26 from a portion near the outer diameter blade portion 21N and a portion 29C2 extending so as to move away from the front edge portion 26. ing.

Even with the above-described configuration, the weight of the blade body 21 can be further reduced, and the sink marks at the time of molding that may occur in the thick portion of the blade body 21 (near the maximum thickness portion 21Ma) are further reduced or reduced. Is possible. Moreover, the imbalance that occurs when the centrifugal fan 10E rotates can be significantly suppressed, and the vibration noise of the centrifugal fan 10E can be further reduced.

[Second Modification of Embodiment 4]
With reference to FIG. 13, a centrifugal fan 10F according to a second modification of the fourth embodiment will be described. FIG. 13 is an enlarged front view showing a part (blade body 21) of the centrifugal fan 10F.

The centrifugal fan 10F in the present embodiment (FIG. 13) and the centrifugal fan in each of the above-described embodiments are formed by separating the inner diameter side blade portion 21M and the outer diameter side blade portion 21N in the centrifugal fan 10F from each other. It is different in that it is.

Even with the above-described configuration, the weight of the blade body 21 can be further reduced, and the sink marks at the time of molding that may occur in the thick portion of the blade body 21 (near the maximum thickness portion 21Ma) are further reduced or reduced. Is possible. Further, the imbalance that occurs when the centrifugal fan 10F rotates can be significantly suppressed, and the vibration noise of the centrifugal fan 10F can be further reduced.

[Embodiment 5]
In the present embodiment, a molding die used at the time of manufacturing the centrifugal fan 10 (FIG. 1) in the first embodiment, a blower using the centrifugal fan 10 and an air cleaner will be described. The contents disclosed below in the present embodiment are also applicable to the centrifugal fans in the above-described Embodiments 2 to 4 and these modifications.

(Mold 110 for molding)
FIG. 14 is a cross-sectional view showing a molding die 110 used when the centrifugal fan 10 is manufactured. The molding die 110 has a fixed side die 114 and a movable side die 112. The fixed side mold 114 and the movable side mold 112 define a cavity 116 having substantially the same shape as the centrifugal fan 10 and into which a fluid resin is injected.

The molding die 110 may be provided with a heater (not shown) for enhancing the fluidity of the resin injected into the cavity 116. The installation of such a heater is particularly effective when, for example, a synthetic resin with increased strength such as an AS resin containing glass fiber is used.

(Blower 120)
FIG. 15 is a cross-sectional view showing a blower 120 using the centrifugal fan 10. 16 is a cross-sectional view showing a cross-sectional shape of the blower 120 along the line XVI-XVI in FIG. The blower 120 includes a drive motor 128 (FIG. 16), the centrifugal fan 10, and a casing 129 in the outer casing 126.

The output shaft of the drive motor 128 is connected to the boss portion 16 (FIG. 16) of the centrifugal fan 10. The casing 129 has a guide wall 129a. The guide wall 129 a is formed by a substantially 3/4 arc arranged on the outer periphery of the centrifugal fan 10. The guide wall 129a is formed to increase the speed of the airflow while guiding the airflow generated by the rotation of the blade body 21 in the rotation direction of the blade body 21.

The suction part 130 (FIG. 16) and the blowing part 127 are formed in the casing 129. The suction part 130 is formed on the extension of the rotation shaft 101. The blowing portion 127 is formed to be opened from a part of the guide wall 129a to one side in the tangential direction of the guide wall 129a. The blowing portion 127 has a rectangular tube shape protruding from a part of the guide wall 129a to one side in the tangential direction of the guide wall 129a.

The centrifugal fan 10 rotates in the direction shown by the arrow 103 (FIG. 15) by driving the drive motor 128 (FIG. 16). At this time, air is taken into the casing 129 from the suction portion 130 and sent out from the inner peripheral space 131 of the centrifugal fan 10 to the outer peripheral space 132. The air sent out to the outer peripheral side space 132 flows in the circumferential direction along the direction indicated by the arrow 104 and is blown to the outside through the blowing unit 127.

(Air cleaner 140)
FIG. 17 is a cross-sectional view showing an air cleaner 140 using the centrifugal fan 10. The air cleaner 140 includes a housing 144, a blower 150, a duct 145, and a (HEPA: High Efficiency Particulate Air Filter) filter 141.

The housing 144 has a rear wall 144a and a top wall 144b. The housing 144 is formed with a suction port 142 for sucking air in a room where the air purifier 140 is installed. The suction port 142 is formed in the rear wall 144a. The housing 144 further has a blowout port 143 that discharges clean air toward the room. The outlet 143 is formed in the top wall 144b. In general, the air cleaner 140 is installed near the wall so that the rear wall 144a faces the indoor wall.

The filter 141 is disposed inside the housing 144 so as to face the suction port 142. The air introduced into the housing 144 through the suction port 142 passes through the filter 141, thereby removing foreign substances and obtaining clean air.

The blower 150 sucks indoor air into the housing 144 and sends the air purified by the filter 141 into the room through the outlet 143. The blower 150 includes the centrifugal fan 10, a casing 152, and a drive motor 151. The casing 152 has a guide wall 152a. The casing 152 is formed with a suction part 153 and a blowing part 154.

The duct 145 is provided above the blower 150 and is provided as an air guide path that guides clean air from the casing 152 to the outlet 143. The duct 145 has a shape that forms a rectangular tube whose lower end is connected to the blowing portion 154 and whose upper end is open. The duct 145 is configured to guide the clean air blown out from the blowout portion 154 to a laminar flow toward the blowout port 143.

In the air cleaner 140 having such a configuration, the blade body 21 is rotated by driving the blower 150, and the indoor air is sucked into the housing 144 from the suction port 142. At this time, an air flow is generated between the suction port 142 and the blowout port 143, and foreign matters such as dust contained in the sucked air are removed by the filter 141.

Clean air obtained through the filter 141 is sucked into the casing 152. At this time, the clean air sucked into the casing 152 becomes a laminar flow by the guide wall 152 a around the blade body 21. The laminar air is guided to the blowing part 154 along the guiding wall 152a and is blown into the duct 145 from the blowing part 154. Air is discharged from the outlet 143 toward the external space.

According to the air cleaner 140 configured as described above, the power consumption of the drive motor 151 can be reduced by using the centrifugal fan 10 having excellent blowing ability. Thereby, the air cleaner 140 that can contribute to energy saving can be realized. In the present embodiment, the air cleaner has been described as an example. In addition to the above, for example, the above-described device for sending out a fluid such as an air conditioner (humidifier), a humidifier, a cooling device, and a ventilation device is used. The centrifugal fan in each embodiment can also be applied.

For example, if the centrifugal fan in each of the above-described embodiments is used as a sirocco fan used for an air conditioner that is suspended from the ceiling, the capacity can be increased and the noise can be reduced. In addition, it is possible to reduce the size of the fan and the size of the main body while keeping the noise constant. As a result of downsizing, it can also be installed as a wall-mounted air conditioner. The air conditioner that can be hung from a dotted shape requires large-scale construction, but the wall-mounted room air conditioner only requires general construction, and there is a great demand from the world. Moreover, the centrifugal fan in each of the above-described embodiments can be applied to a cross flow fan built in a wall-mounted room air conditioner.

[Experimental example]
With reference to FIGS. 18 to 33, experimental examples performed in relation to the above-described embodiments will be described. In the description, as shown in FIG. 18, a straight line connecting the front edge portion 26 and the rear edge portion 27 of the blade body 21 is defined as a chord line LN3. The length of the chord line LN3 is a chord length C. The length of the perpendicular LN4 at the position P15 where the length of the perpendicular drawn from the suction surface 24 of the blade body 21 with respect to the chord line LN3 is the maximum is warp t. The value of warp t / chord length C is defined as a warp ratio m.

As shown in FIG. 19, nine types of centrifugal fans were prepared as Experimental Examples 1 to 9. As conditions common to the centrifugal fans in Experimental Examples 1 to 9, all of the fan's outer shape is set to 236 mm, the height is set to 80 mm, the chord length C of the blade body 21 is set to 20 mm, and the blade body The minimum blade thickness of 21 was set to 1 mm.

(Experimental example 1)
As shown in FIGS. 19 and 20, in the centrifugal fan 10S1 of Experimental Example 1, the warp t was set to 4.0 mm, and the maximum blade thickness was set to 1.0 mm. The warpage ratio m (warpage t / chord length C) is 0.2, and the blade thickness ratio representing the ratio between the minimum blade thickness and the maximum blade thickness is 1.0.

(Experimental examples 2 to 4)
As shown in FIG. 19, in the centrifugal fans of Experimental Examples 2 to 4, the warp t is set to 4.22 mm, 4.5 mm, and 5.0 mm, respectively, and the maximum blade thickness is 1.55 mm, 2.8 mm, 3 mm Set to 15 mm. The warpage ratio m (warpage t / chord length C) is 0.211, 0.225, and 0.25, respectively, and the blade thickness ratio is 1.55, 2.8, and 3.15.

(Experimental example 5)
As shown in FIGS. 19 and 21, in the centrifugal fan 10S5 of Experimental Example 5, the warp t was set to 5.6 mm and the maximum blade thickness was set to 3.3 mm. The warpage ratio m (warpage t / chord length C) is 0.28, and the blade thickness ratio is 3.3.

(Experimental examples 6 to 8)
As shown in FIG. 19, in the centrifugal fans of Experimental Examples 6 to 8, the warp t is set to 6.6 mm, 7.2 mm, and 8.0 mm, respectively, and the maximum blade thickness is 3.46 mm, 3.6 mm, .67 mm. The warpage ratio m (warpage t / chord length C) is 0.33, 0.36, and 0.4, respectively, and the blade thickness ratio is 3.46, 3.6, and 3.67.

(Experimental example 9)
As shown in FIGS. 19 and 22, in the centrifugal fan 10S9 of Experimental Example 9, the warp t was set to 8.2 mm and the maximum blade thickness was set to 3.84 mm. The warp ratio m (warp t / chord length C) is 0.41, and the blade thickness ratio is 3.84.

(Relationship between warpage ratio m and air volume)
Referring to FIGS. 19 and 23, the centrifugal fans of Experimental Examples 1 to 9 having the above-mentioned conditions were rotated at 1250 rpm, and the air volume was measured. The results shown in the table of FIG. 19 were obtained. FIG. 23 is a graph of the table shown in FIG. It can be seen that the air volume increases as the warp ratio m increases. In view of the increase rate of the air volume, it is understood that the warp ratio m is preferably 0.25 or more.

(Relationship between warpage ratio m and noise)
Referring to FIG. 19 and FIG. 24, the centrifugal fans of Experimental Examples 1 to 9 having the above-mentioned conditions were rotated so that the air flow was 7.5 m ³ / min, and the noise was measured. The results as shown in Fig. 1 were obtained. FIG. 24 is a graph of the table shown in FIG. In view of the noise reduction rate, it can be seen that the warp ratio m is preferably 0.25 or more.

(Relationship between warpage ratio m and power consumption)
Referring to FIG. 19 and FIG. 25, the centrifugal fans of Experimental Examples 1 to 9 having the above-mentioned conditions were rotated so that the air volume was 7.5 m ³ / min, and the power consumption was measured. The results shown in the table were obtained. FIG. 25 is a graph of the table shown in FIG. It can be seen that the warp ratio m is preferably 0.25 or more in view of the power consumption reduction rate.

(Relationship between maximum blade thickness and air flow)
FIG. 26 is a graph showing the relationship between the maximum blade thickness of Experimental Examples 1 to 9 having the above conditions and the air volume obtained when the centrifugal fans of Experimental Examples 1 to 9 are rotated at 1250 rpm. It can be seen that the airflow increases in a generally linear relationship as the maximum blade thickness increases.

(Relationship between maximum blade thickness and noise)
FIG. 27 shows the maximum blade thickness of Experimental Examples 1 to 9 having the above-mentioned conditions and the noise generated when the centrifugal fan of Experimental Examples 1 to 9 is rotated so that the air volume becomes 7.5 m ³ / min. It is a graph which shows the relationship. It can be seen that when the maximum blade thickness exceeds 2.8 mm (Experimental Example 3 shown in FIG. 19), the noise sharply decreases. It can be seen that noise is minimized when the maximum blade thickness is 3.6 mm (Experimental Example 7 shown in FIG. 19).

(Relationship between maximum blade thickness and power consumption)
FIG. 28 shows the maximum blade thickness of Experimental Examples 1 to 9 having the above-described conditions and the power consumed when the centrifugal fans of Experimental Examples 1 to 9 are rotated so that the air volume is 7.5 m ³ / min. It is a graph which shows the relationship. It can be seen that when the maximum blade thickness exceeds 3.15 mm (Experimental Example 4 shown in FIG. 19), the power consumption sharply decreases. It can be seen that the power consumption is minimized when the maximum blade thickness is 3.6 mm (Experimental Example 7 shown in FIG. 19).

(Relationship between blade thickness ratio and air volume)
FIG. 29 is a graph showing the relationship between the blade thickness ratio of Experimental Examples 1 to 9 having the above conditions and the air volume (relative value) obtained when the centrifugal fans of Experimental Examples 1 to 9 are rotated at 1250 rpm. is there. It can be seen that as the blade thickness ratio increases, the air volume increases in a generally linear relationship.

(Relationship between blade thickness ratio and noise)
FIG. 30 shows the blade thickness ratio of Experimental Examples 1 to 9 having the above-mentioned conditions and the noise generated when the centrifugal fans of Experimental Examples 1 to 9 are rotated so that the air volume becomes 7.5 m ³ / min ( It is a graph which shows the relationship with relative value. It can be seen that when the blade thickness ratio exceeds 2.8 mm (Experimental Example 3 shown in FIG. 19), the noise sharply decreases. It can be seen that noise is minimized when the blade thickness ratio is 3.6 mm (Experimental Example 7 shown in FIG. 19).

(Relationship between blade thickness ratio and power consumption)
FIG. 31 shows the blade thickness ratio of Experimental Examples 1 to 9 having the above conditions and the electric power consumed when the centrifugal fans of Experimental Examples 1 to 9 are rotated so that the air volume becomes 7.5 m ³ / min ( It is a graph which shows the relationship with relative value. It can be seen that when the blade thickness ratio exceeds 3.15 mm (Experimental Example 4 shown in FIG. 19), the power consumption sharply decreases. It can be seen that the power consumption is minimized when the blade thickness ratio is 3.6 mm (Experimental Example 7 shown in FIG. 19).

(Summary)
Based on the results of the above experimental examples 1 to 9, it can be seen that a more preferable improvement effect can be obtained when the warp ratio m is 0.25 or more from the viewpoint of increasing air volume, reducing noise, and reducing power consumption. .

(Other experimental examples)
FIG. 32 is an enlarged front view showing a part of the centrifugal fan 10S7 based on the experimental example 7. In the centrifugal fan 10S7 of Experimental Example 7 (FIG. 19), the warp t was set to 7.2 mm, and the maximum blade thickness was set to 3.6 mm. The warp ratio m (warp t / chord length C) is 0.36, and the blade thickness ratio is 3.6. According to such a centrifugal fan 10S7, as shown in FIG. 19, the air volume increased by 8%, the noise decreased by 1.87 dB, and the power consumption decreased by 6%.

The centrifugal fan 10S7a shown in FIG. 33 is common to the centrifugal fan 10S7 shown in FIG. 32 in that the warp t is set to 7.2 mm. However, in the centrifugal fan 10S7a, the maximum blade thickness is set to 1.0 mm. Set. The warp ratio m (warp t / chord length C) of the centrifugal fan 10S7a is 0.36, which is the same as that of the centrifugal fan 10S7, but the blade thickness ratio of the centrifugal fan 10S7a is 1.0. According to the centrifugal fan 10S7a, the air volume is increased by 4%, the noise is increased by 1 dB, and the power consumption is reduced by 1%.

According to the comparison of the centrifugal fans 10S7 and 10S7a described above, it is understood that not only the warp ratio m but also the maximum blade thickness and blade thickness ratio can be optimized to increase the air volume, reduce noise, and reduce power consumption. .

As mentioned above, although embodiment, its modification, and experiment example were demonstrated, said disclosure content is an illustration and restrictive at no points. The technical scope of the present invention is defined by the terms of the claims, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

The contents disclosed in this specification can be industrially used mainly for household electric appliances having an air blowing function such as an air purifier and an air conditioner.

10, 10A, 10B, 10C, 10D, 10E, 10F, 10S7a, 10S1, 10S5, 10S9, 10S7 Centrifugal fan, 12, 13 outer peripheral frame, 16 boss part, 21 blade body, 21A front blade body, 21B rear blade body 21M inner diameter blade part, 21Ma maximum thickness part, 21Mb enlarged part, 21Mc reduced part, 21N outer diameter blade part, 21Np plate part, 23 blade surface, 24, 24A, 24B, 24M, 24Np negative pressure surface, 24L length 24R, 25R wire, 25, 25M, 25Np pressure surface, 26 front edge, 27 rear edge, 29, 29A, 29B through hole, 29C notch, 29C1, 29C2 portion, 101 rotating shaft, 102, 103, 104, H arrow, 110 mold for molding, 112 movable mold, 114 fixed side Mold, 116 cavity, 120, 150 blower, 127, 154 blowing part, 128, 151 drive motor, 129, 152 casing, 129a, 152a guide wall, 130, 153 suction part, 131, 132 space, 140 air cleaner, 141 Filter, 142 inlet, 143 outlet, 144 housing, 144a rear wall, 144b top wall, 145 duct, AS glass fiber, C chord length, D interval, L1, L2, L3, L4, L5, L6 Distance, LN1, LN2 straight line, LN3 chord line, LN4, W1, W2 perpendicular line, P1, P3, P4, P5, P6 locations, P2 locations (maximum thickness position), P10, P11, P12 points, P13, P15 locations, WA, WB speed, h1, h3, h4, h5 h6 blade thickness, h2 maximum thickness, m warp ratio, t, t1, t2 warpage.

Claims (11)

1. It has a front edge part into which air flows in and a rear edge part from which air flows out, and includes a plurality of blade bodies provided at intervals in the circumferential direction,
   Each of the plurality of blade bodies extends between the front edge portion and the rear edge portion, and has a positive pressure surface positioned on the rotation direction side of the blade body, and the rotation direction of the blade body. A wing surface consisting of a suction surface located on the opposite side is formed,
   The plurality of blade bodies include a front blade body, and a rear blade body that faces the front blade body with the space therebetween and is positioned on the opposite side of the rotation direction with respect to the front blade body,
   The shortest distance from any location on the suction surface of the front blade body to the pressure surface of the rear blade body is defined as the interblade distance at the location,
   The front blade body has a maximum thickness portion that defines the maximum thickness of the front blade body, and a position on the suction surface in the maximum thickness portion is defined as a maximum thickness position,
   A range between the maximum thickness position of the suction surface of the front blade body and the front edge portion is defined as an inner diameter side suction surface,
   A range between the maximum thickness position of the suction surface of the front blade body and the rear edge portion is defined as an outer diameter side suction surface,
   When the length from the front edge to the rear edge of the suction surface of the front blade is defined as the suction surface length,
   The distance between the blades on the inner diameter side suction surface is longer than the distance between the blades at the maximum thickness position,
   The inter-blade distance in a range between the maximum thickness position of the outer diameter side negative pressure surface and a position separated from the maximum thickness position by a length equal to or more than half the negative pressure surface length is substantially constant. There is a centrifugal fan.
2. It has a front edge part into which air flows in and a rear edge part from which air flows out, and includes a plurality of blade bodies provided at intervals in the circumferential direction,
   Each of the plurality of blade bodies extends between the front edge portion and the rear edge portion, and has a positive pressure surface positioned on the rotation direction side of the blade body, and the rotation direction of the blade body. A wing surface consisting of a suction surface located on the opposite side is formed,
   Each of the plurality of blade bodies has an inner diameter side blade portion including the front edge portion, and an outer diameter side blade portion including the rear edge portion, which is located on the radially outer side of the inner diameter side blade portion. ,
   The inner diameter blade portion is
   A maximum thickness portion defining the maximum thickness of the inner diameter side blade portion; and
   Located between the leading edge and the maximum thickness portion, an enlarged portion where the blade thickness gradually increases from the side of the leading edge toward the radially outer side,
   A reduced portion where the blade thickness is gradually reduced from the maximum thickness portion side toward the radial outer side, located on the radially outer side than the maximum thickness portion;
   Both the negative pressure surface of the inner diameter side blade portion and the positive pressure surface of the inner diameter side blade portion have a surface shape that curves in a convex shape toward the opposite side in the rotation direction,
   The curvature of the suction surface of the inner diameter blade portion is larger than the curvature of the pressure surface of the inner blade portion,
   The outer diameter blade portion includes a plate-like portion extending from the rear edge side to the radially inner side with substantially the same blade thickness,
   The curvature of the suction surface of the plate-like portion and the curvature of the pressure surface of the plate-like portion are both smaller than the curvature of the suction surface of the inner diameter blade portion,
   Centrifugal fan.
3. The pressure surface of the inner diameter blade portion and the pressure surface of the outer diameter blade portion are tangent to each other,
   The suction surface of the inner diameter blade portion and the suction surface of the outer diameter blade portion are tangent to each other.
   The centrifugal fan according to claim 2.
4. The maximum thickness of the outer diameter side blade portion is smaller than the maximum thickness of the inner diameter side blade portion,
   The warp of the outer diameter side blade portion is smaller than the warp of the inner diameter side blade portion,
   The centrifugal fan according to claim 2 or 3.
5. The inner diameter blade portion is provided with a through hole extending in a direction parallel to the rotation axis,
   The through hole is formed so as to include the maximum thickness portion, or is formed one by one on the radially inner side and the radially outer side of the maximum thickness portion,
   The centrifugal fan according to any one of claims 2 to 4.
6. When the inner peripheral surface forming the through hole in the inner diameter side blade portion is viewed from a direction parallel to the rotation axis, the inner peripheral surface has a crescent shape,
   The centrifugal fan according to claim 5.
7. A straight line connecting the leading edge and the trailing edge is defined as a chord line,
   The length of the chord line is C, the length of the perpendicular line at the position where the length of the perpendicular line drawn from the suction surface of the blade body to the chord line is maximum is t, and t / C If the value is defined as the warp ratio m,
   Each of the plurality of blades is formed such that the warp ratio m is 0.25 or more.
   The centrifugal fan according to any one of claims 1 to 6.
8. The plurality of blade bodies are configured to form a constant velocity cascade.
   The centrifugal fan according to any one of claims 1 to 7.
9. Formed by resin,
   The centrifugal fan according to any one of claims 1 to 8.
10. Used for molding the centrifugal fan according to claim 9,
    Mold for molding.
11. A blower comprising: the centrifugal fan according to any one of claims 1 to 9; and a drive motor connected to the centrifugal fan and configured to rotate the plurality of blade bodies.
    Fluid feeder.

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