JP7645632B2 - Centrifugal fans, molds and blowers - Google Patents

Description

The present invention relates to a centrifugal fan, a mold, and a blower.

In recent years, attention has been focused on biomimetics, a technology that mimics and utilizes the diverse functions of living organisms. Nature Technology (registered trademark) is known as an example of a manufacturing process that employs biomimetic technology in electrical products and other products.

General air conditioners use a cross-flow fan, also known as a crossflow fan, as the blower. However, to obtain a sufficient amount of airflow, it is preferable to use a centrifugal fan, also known as a sirocco fan, as the blower.

A centrifugal fan has multiple blades arranged in a circle at equal intervals, and as the fan rotates, air flows in from near the center of rotation and flows out from the outside of the fan. In a centrifugal fan, the flow path through which the air flows is formed by the positive pressure surface and negative pressure surface of adjacent blades.

When the negative pressure (lift) acting on the blade overcomes the kinetic energy of the air flow in the flow passage, the air flow separates from the negative pressure surface of the blade, reducing the performance of the blade.

Patent document 1 discloses a centrifugal fan that reduces the loss of lift by increasing the thickness of the inlet side of the blades.

International Publication WO2018/189931

However, in the conventional technology described above, the thickness of the blades on the air inlet side is made thick, which narrows the inlet of the flow path, increases frictional resistance, reduces the air volume, and creates the problem that the fan's capacity cannot be sufficiently increased.

One aspect of the present invention aims to realize a centrifugal fan that can fully utilize its capabilities as a fan.

In order to solve the above problems, a centrifugal fan according to one aspect of the present invention has a rear edge portion from which air flows out, and a leading edge portion located closer to the rotating shaft than the rear edge portion and into which air flows in, and comprises a plurality of blade bodies arranged at intervals from each other in a rotational direction that is the circumferential direction of the rotating shaft, wherein the blade bodies have a first blade portion, an end portion on the rear edge portion side which is a first plate-shaped portion having a constant thickness, a second blade portion located closer to the rear edge portion than the first blade portion, connected to the first plate-shaped portion at an end portion on the leading edge portion side and having a thickness that increases toward the rear edge portion, a third blade portion located closer to the rear edge portion than the second blade portion and having a thickness that decreases toward the rear edge portion, and a fourth blade portion located closer to the rear edge portion than the third blade portion and including a second plate-shaped portion of constant thickness, and wherein when viewed from the axial direction of the rotating shaft, a boundary between the second blade portion and the third blade portion is convex toward the rear side in the rotational direction. a first surface of the blade body that is located on the front side in the rotation direction and a second surface of the blade body that is located on the rear side, which is opposite to the front side in the rotation direction, the first surface of the second blade portion is a curved surface, the first surface of the second blade portion and the first surface of the third blade portion are located on the front side in the rotation direction of a plane extending from the first surface of the first plate-shaped portion, the second blade portion includes a first portion that is located at an end of the second blade portion on the leading edge side and connected to the first plate-shaped portion , a second portion that is located at an end of the second blade portion on the trailing edge side and connected to the boundary , and a third portion that connects the first portion and the second portion, the second surface of the third portion is a curved surface having a smaller curvature than the first surface of the third portion, and the second surface of the second portion is a curved surface having a larger curvature than the first surface of the second portion.
In order to solve the above problems, a centrifugal fan according to one aspect of the present invention has a rear edge portion from which air flows out, and a leading edge portion located closer to the rotating shaft than the rear edge portion and into which air flows in, and the plurality of blade bodies are arranged at intervals from each other in a rotation direction that is the circumferential direction of the rotating shaft , the blade bodies having a first blade portion whose end on the rear edge portion side is a first plate-shaped portion with a constant thickness, a second blade portion located closer to the rear edge portion than the first blade portion, connected to the first plate-shaped portion at an end on the leading edge portion side and having a thickness that increases toward the rear edge portion, and a third blade portion located closer to the rear edge portion than the second blade portion and having a thickness that decreases toward the rear edge portion, when viewed from the axial direction of the rotating shaft, a boundary between the second blade portion and the third blade portion is curved convexly toward the rear side in the rotation direction, and a surface located on the front side in the rotation direction is defined as a first surface, and a surface located on the rear side, which is in the opposite direction to the front side in the rotation direction, is defined as a second surface, the first surface of the second blade portion is a curved surface, the first surface of the second blade portion and the first surface of the third blade portion are located on the front side in the rotation direction of a plane extending from the first surface of the first plate-shaped portion, the second blade portion includes a first portion located at an end of the second blade portion on the leading edge side and connected to the first plate-shaped portion , a second portion located at an end of the second blade portion on the trailing edge side and connected to the boundary , and a third portion connecting the first portion and the second portion, the second surface of the third portion is a curved surface having a smaller curvature than the first surface of the third portion, and the second surface of the second portion is a curved surface having a larger curvature than the first surface of the second portion.

According to one aspect of the present invention, fans can fully utilize their abilities.

1 is a perspective view of a centrifugal fan according to a first embodiment of the present invention. FIG. FIG. 2 is a front view of the centrifugal fan shown in FIG. 1 . FIG. 3 is a front view of one blade body provided in the centrifugal fan shown in FIG. 2 . FIG. 4 is an explanatory diagram for specifying the shape of the blade body shown in FIG. 3 . FIG. 4 is an explanatory diagram for specifying the shape of the blade body shown in FIG. 3 . FIG. 2 is a schematic diagram showing an air flow of the centrifugal fan shown in FIG. 1 . FIG. 4 is a schematic diagram showing an air flow of a centrifugal fan of a comparative example. FIG. 2 is a cross-sectional view of a molding die used in manufacturing the centrifugal fan shown in FIG. FIG. 2 is a cross-sectional view showing a blower using the centrifugal fan shown in FIG. 1 . 9 is a cross-sectional view taken along line AA in FIG. 8 . FIG. 2 is a cross-sectional view of an air purifier using the centrifugal fan shown in FIG. 1 . 2 is a vertical cross-sectional view of an indoor unit of an air conditioner using the blower fan shown in FIG. 1, as viewed from the side.

[Embodiment 1]
Hereinafter, one embodiment of the present invention will be described in detail.

(Outline of the blower fan)
FIG. 1 is a perspective view of the blower fan 10, and FIG. 2 is a front view of the blower fan 10. As shown in FIG. 1, the blower fan 10 includes two centrifugal fans 11 arranged side by side along a rotating shaft 101. The two centrifugal fans 11 have the same configuration. The reason why the blower fan 10 is composed of two centrifugal fans 11 is to increase the air volume. In other words, the number of centrifugal fans 11 used can be adjusted according to the air volume. For example, a blower fan that combines two or more centrifugal fans 11 is preferably used for a large air conditioner such as an air conditioner. Also, for a small air conditioner such as an air purifier, rather than a large air conditioner such as an air conditioner, a blower fan equipped with one centrifugal fan 11 is preferably used.

The centrifugal fan 11 has an overall roughly cylindrical outer shape. The centrifugal fan 11 has a number of blades 20 arranged at intervals in the direction of rotation. Each of the blades 20 has a rear edge 24b from which air flows out, and a front edge 21b located closer to the rotating shaft 101 than the rear edge 24b and into which air flows in. The centrifugal fan 11 is integrally formed from resin.

The centrifugal fan 11 uses multiple rotating blades 20 to send air taken in from the leading edge 21b to the trailing edge 24b. In other words, the centrifugal fan 11 uses centrifugal force to send air from the leading edge 21b, which is the side closest to the center of rotation, to the trailing edge 24b, which is the radially outer side.

The centrifugal fan 11 further has an outer peripheral frame 12 and a disk body 13. The outer peripheral frame 12 is formed to extend in an annular shape centered on the rotating shaft 101. The disk body 13 forms a connection part with the other centrifugal fan 11. Therefore, the outer peripheral frame 12 and the disk body 13 are arranged at a distance in the axial direction of the rotating shaft 101.

The vanes 20 are spaced apart from one another in the circumferential direction centered on the rotating shaft 101. Here, the vanes 20 are equally spaced apart in the circumferential direction centered on the rotating shaft 101, and are supported by the outer peripheral frame 12 and the disk body 13 at both ends in the axial direction of the rotating shaft 101. The vanes 20 are erected on the disk body 13 and are formed to extend along the axial direction of the rotating shaft 101 toward the outer peripheral frame 12.

(Details of the blade)
Fig. 3 is a front view of the blade body 20 included in the centrifugal fan 11. Fig. 4 is a partial enlarged view for explaining the shape of the blade body 20 shown in Fig. 3. Fig. 5 is a front view for explaining the angle between the positive pressure surface and the negative pressure surface of the blade body 20.

As shown in FIG. 3, the blade body 20 has a positive pressure surface 20a (first surface) located at the front in the direction of rotation (arrow direction) and a negative pressure surface 20b (second surface) located at the rear in the direction of rotation (arrow direction).

As shown in FIG. 4, the blade body 20 has a leading edge 21b at the end of the inlet 11b and a trailing edge 24b at the end of the outlet 11a. The blade body 20 has a first blade 21, a second blade 22, a third blade 23, and a fourth blade 24. The first blade 21 includes a leading edge 21b and a first plate-shaped portion 21a having a substantially constant thickness. The second blade 22 is located closer to the trailing edge 24b than the first blade 21, and the thickness increases toward the trailing edge 24b. The third blade 23 is located closer to the trailing edge 24b than the second blade 22, and the thickness decreases toward the trailing edge 24b. The fourth blade 24 is located closer to the trailing edge 24b than the third blade 23, and includes a trailing edge 24b and a second plate-shaped portion 24a having a substantially constant thickness.

The thickness of the first blade section 21 to the fourth blade section 24 that make up the blade body 20 indicates the thickness in a cross section perpendicular to the rotation axis 101. For example, the thickness at a certain point on the negative pressure surface 20b (second surface) of the blade body 20 is the shortest distance from that point to the positive pressure surface 20a (first surface).

The maximum thickness of the second blade portion 22 and the third blade portion 23 is greater than the maximum thickness of the first blade portion 21 and the maximum thickness of the fourth blade portion 24. Furthermore, since the second blade portion 22 and the third blade portion 23 are adjacent to each other, the boundary between the second blade portion 22 and the third blade portion 23 is the location where the blade body 20 has the maximum thickness.

The blade body 20 is curved convexly in the opposite direction to the rotation direction. For example, the positive pressure surface 20a has a concave surface, and the negative pressure surface 20b has a convex surface. Specifically, the first plate-shaped portion 21a of the first blade portion 21 and the second plate-shaped portion 24a of the fourth blade portion 24 are inclined relative to the radial direction. A plane X1 parallel to the surface of the first plate-shaped portion 21a of the first blade portion 21 opposite the rotation direction intersects with a plane X2 parallel to the surface of the second plate-shaped portion 24a of the fourth blade portion 24 opposite the rotation direction.

The curvature at the boundary B1 between the second blade portion 22 and the third blade portion 23 on the positive pressure surface 20a (first surface) is smaller than the curvature at the boundary B2 between the second blade portion 22 and the third blade portion 23 on the negative pressure surface 20b (second surface). For example, the boundary B2 of the negative pressure surface 20b is located on the opposite side of the rotational direction from a surface where the positive pressure surface 20a is offset in the opposite direction of the rotational direction so as to overlap with the negative pressure surface 20b of the first plate-shaped portion 21a and the second plate-shaped portion 24a (see FIG. 3).

In this way, the curvature at the boundary B1 between the second blade portion 22 and the third blade portion 23 on the positive pressure surface 20a of the blade body 20 is smaller than the curvature at the boundary B2 between the second blade portion 22 and the third blade portion 23 on the negative pressure surface 20b, making it possible to increase the thickness of the second blade portion 22 and the third blade portion 23.

Where the blade body 20 is curved, a portion where the blade body 20 is thicker (for example, the diagonal lined portion with a triangular cross section shown in Figure 3) is formed. This makes it possible to reduce separation of the air flow from the blade body.

For example, as shown in FIG. 5, the angle on the positive pressure surface 20a (first surface) at the intersection between a plane X3 parallel to the surface of the first plate-shaped portion 21a facing in the direction of rotation and a plane X4 parallel to the surface of the second plate-shaped portion 24a facing in the direction of rotation is θ1. The angle on the negative pressure surface 20b (second surface) at the intersection between a plane X1 parallel to the surface of the first plate-shaped portion 21a facing in the direction of rotation and a plane X2 parallel to the surface of the second plate-shaped portion 24a facing in the direction of rotation is θ2. The angles θ1 and θ2 may be approximately the same. For example, θ1 and θ2 may be 80° to 110°. However, the angles θ1 and θ2 are not limited to these. For example, θ1 may be smaller than θ2, and θ1 may be larger than θ2.

Here, as shown in FIG. 4, it is preferable that the positive pressure surface 20a side of the second blade portion 22 of the blade body 20 does not protrude in the opposite direction to the rotation direction with respect to the plane X3 extending from the positive pressure surface 20a of the first plate-shaped portion 21a of the first blade portion 21. This is to increase the lift on the negative pressure surface 20b side in the flow path formed between the adjacent blade bodies 20 and suppress the flow from being separated from the blade body 20. In other words, in the air flow path formed between the adjacent blade bodies 20, the positive pressure surface 20a at the boundary between the second blade portion 22 and the third blade portion 23 does not protrude in the opposite direction to the rotation direction with respect to the plane X3, thereby suppressing the decrease in flow velocity near the positive pressure surface 20a. As a result, the flow velocity near the positive pressure surface 20a becomes equal to the flow velocity near the negative pressure surface 20b of the opposing blade body 20. This allows the flow velocity in the flow passage to be kept approximately constant at an increased speed, making it possible to significantly increase the time and distance margins until the kinetic energy of the air flow is overcome by the negative pressure acting on the blade body 20. This also prevents the air flow from separating from the negative pressure surface 20b of the blade body 20, which in turn prevents the performance of the blade body 20 from deteriorating, and by preventing separation, it is possible to significantly reduce the generation of noise.

To achieve this effect, for example, the blade body 20 is formed so that the positive pressure surface 20a of the second blade portion 22 is located forward in the direction of rotation of the plane X3 that is an extension of the positive pressure surface 20a of the first plate-shaped portion 21a.

The blade body 20 is formed so that the negative pressure surface 20b of the second blade portion 22 is located forward in the direction of rotation of the plane X1 that is an extension of the negative pressure surface 20b of the first plate-shaped portion 21a.

Furthermore, the blade body 20 is formed so that the positive pressure surface 20a of the third blade portion 23 is located forward in the direction of rotation of the plane X4 that is an extension of the positive pressure surface 20a of the second plate-shaped portion 24a.

The blade body 20 is formed so that the negative pressure surface 20b of the third blade portion 23 is located forward in the direction of rotation of the plane X2 that is an extension of the negative pressure surface 20b of the second plate-shaped portion 24a.

However, the configuration of the blade body 20 is not limited to these. For example, the negative pressure surface 20b of the second blade portion 22 or the third blade portion 23 may be located rearward of the planes X1 and X2 in the direction of rotation. For example, the positive pressure surface 20a of the second blade portion 22 or the third blade portion 23 may be located rearward of the planes X3 and X4 in the direction of rotation.

(effect)
Fig. 6 is a schematic diagram showing the air flow of the centrifugal fan 11 shown in Fig. 1. Fig. 7 is a schematic diagram showing the air flow of a centrifugal fan of a comparative example.

In both of the flow paths shown in Figures 6 and 7, the flow velocity in the flow path can be kept approximately uniform at an increased speed, making it possible to significantly extend the time and distance margin until the kinetic energy of the flow is defeated by the negative pressure acting on the blade body 20 (a vortex is generated).

However, the blade body 1020 shown in FIG. 7 is thick near the leading edge 1021. As a result, the inlet side of the flow path (between the positive pressure surface 1020a and the negative pressure surface 1020b) formed by adjacent blade bodies 1020 is narrow, making it difficult for air to enter, increasing the frictional resistance of the air, and reducing the air volume.

In contrast, in the blade body 20 shown in FIG. 6, the presence of the first plate-shaped portion 21a results in a small thickness near the leading edge portion 21b of the first blade portion 21. As a result, the inlet portion 11b side of the flow path (between the positive pressure surface 20a and the negative pressure surface 20b) formed by adjacent blade bodies 20 is wide, making it easier for air to enter, reducing air friction resistance and increasing the air volume.

Therefore, the centrifugal fan 11 using the blade body 20 has the effect of reducing the separation of the air flow and reducing frictional resistance, thereby allowing the fan to fully perform its functions.

It should be noted that another blade portion may exist between the second blade portion 22 and the third blade portion 23. For example, another blade portion may exist that has a substantially constant thickness. Also, another blade portion may exist that has a thickness that decreases toward the trailing edge portion 24b and then increases in thickness. For example, the negative pressure surface of the other blade portion may have a shape that is nearly flat.

[Embodiment 2]
Other embodiments of the present invention will be described below. For ease of explanation, the same reference numerals are given to members having the same functions as those described in the above embodiment, and the description thereof will not be repeated.

In this embodiment, we will explain the molding die used in manufacturing the centrifugal fan 11 of embodiment 1, and the blower and air conditioner using the centrifugal fan 11.

(Molding die)
8 is a cross-sectional view showing a molding die 110 used in manufacturing the centrifugal fan 11. The molding die 110 has a fixed die 114 and a movable die 112. The fixed die 114 and the movable die 112 define a cavity 116 that has approximately the same shape as the centrifugal fan 11. The centrifugal fan 11 is molded by injecting a fluid resin into the cavity 116.

The molding die 110 may be provided with a heater (not shown) to increase the fluidity of the resin injected into the cavity 116. The installation of such a heater is particularly effective when using a synthetic resin with increased strength, such as glass fiber-reinforced AS resin.

Below, we will explain the blower and air conditioner that use the centrifugal fan 11.

(Blower)
Fig. 9 is a cross-sectional view showing a blower 120 using the centrifugal fan 11. Fig. 10 is a cross-sectional view showing the cross-sectional shape of the blower 120 taken along line A-A in Fig. 9. The blower 120 (blower device) has a drive motor 128 (Fig. 9), the centrifugal fan 11, and a casing 129 inside an exterior casing 126.

The output shaft of the drive motor 128 is connected to the boss portion 16 (Figure 10) of the centrifugal fan 11. The casing 129 has a guide wall 129a. The guide wall 129a is formed by a roughly 3/4 arc arranged on the outer periphery of the centrifugal fan 11. The guide wall 129a is formed to guide the airflow generated by the rotation of the blade body 20 in the direction of rotation of the blade body 20, while increasing the speed of the airflow.

The casing 129 is formed with a suction section 130 (Fig. 10) and a blowing section 127. The suction section 130 is formed at a position on an extension of the rotation shaft 101. The blowing section 127 is formed by opening from a part of the guide wall 129a to one side in the tangential direction of the guide wall 129a. The blowing section 127 has a square cylindrical shape that protrudes from a part of the guide wall 129a to one side in the tangential direction of the guide wall 129a.

When the drive motor 128 (Fig. 10) is driven, the centrifugal fan 11 rotates in the direction indicated by the arrow 103 (Fig. 9). At this time, air is taken into the casing 129 from the suction section 130 and is sent out from the inner space 131 of the centrifugal fan 11 to the outer space 132. The air sent out to the outer space 132 flows circumferentially along the direction indicated by the arrow 104 and is blown to the outside through the blowing section 127.

(Air purifier)
11 is a cross-sectional view showing an air purifier 140 as an air conditioner using the centrifugal fan 11. The air purifier 140 (blower device) has a housing 144, a blower 150, a duct 145, and a (HEPA: High Efficiency Particulate Air Filter) filter 141.

The blower 150 includes a centrifugal fan 11 and a drive motor 151 that rotates the centrifugal fan 11 around the rotating shaft 101.

The housing 144 has a rear wall 144a and a top wall 144b. The housing 144 has an intake port 142 for drawing in air from the room in which the air purifier 140 is installed. The intake port 142 is formed in the rear wall 144a. The housing 144 also has an outlet port 143 for discharging purified air into the room. The outlet port 143 is formed in the top wall 144b. In general, the air purifier 140 is installed against a wall with the rear wall 144a facing the wall in the room.

The filter 141 is disposed inside the housing 144, facing the suction port 142. The air introduced into the housing 144 through the suction port 142 passes through the filter 141, whereby foreign matter is removed, and the air becomes purified. A suction section 153 and a blowing section 154 are formed inside the housing 144. The drive motor 151 is fixed to the inner wall 152 of the housing 144.

(Air conditioner indoor unit)
FIG. 12 is a cross-sectional view showing an indoor unit 201 of an air conditioner as an air conditioner using a blower fan 10 having two centrifugal fans 11.

As shown in FIG. 12, the indoor unit 201 (blower device) of the air conditioner includes an indoor unit main body 202 and an air guide plate 203 provided on the front surface of the indoor unit main body 202. The indoor unit main body 202 includes a cabinet 230, a blower 213, a heat exchanger 214, and a drain pan 221. The blower 213 includes a blower fan 10 and a drive motor that rotates the blower fan 10.

The indoor unit body 202 has a first suction port 211 at the top. The indoor unit body 202 has a second suction port 212 at the bottom. The indoor unit body 202 has an outlet 217 at the front. The indoor unit body 202 has a first filter 215 on the inside (lower side) of the first suction port 211, and a second filter 216 on the inside (upper side) of the second suction port 212. The first filter 215 is, for example, a filter that has a function equivalent to a prefilter, has lower performance than the second filter 216, and has smaller ventilation resistance than the second filter 216. The second filter 216 is, for example, a HEPA filter (High Efficiency Particulate Air Filter), has higher performance than the first filter 215, and has larger ventilation resistance than the first filter 215.

Air drawn into the indoor unit 201 from the first intake port 211 passes through the first filter 215, is blown by the blower fan 10 to the heat exchanger 214, and is blown out from the outlet 217. Air drawn into the indoor unit 201 from the second intake port 212 passes through the second filter 216, is blown by the blower fan 10 to the heat exchanger 214, and is blown out from the outlet 217.

The first air intake 211 is provided with an opening/closing lid 218 that opens and closes the first air intake 211. The opening/closing lid 218 is attached to the top of the cabinet 230. The opening/closing lid 218 is in an open state when operating in air conditioning mode. The opening/closing lid 218 is in a closed state when the air conditioner is stopped or when operating in air purification mode.

The air conditioning mode is an operating mode of an air conditioner in which the air conditioning function is prioritized over the air purification function. The air purification mode is an operating mode of an air conditioner in which the air purification function is prioritized over the air conditioning function. In the air conditioning mode, air is mainly drawn in through the first intake port 211. On the other hand, in the air purification mode, air is only drawn in through the second intake port 212.

The air guide plate 203 is positioned so that the air (airflow) blown out from the air outlet 217 flows diagonally upwards during cooling operation and diagonally downwards during heating operation.

〔summary〕
A centrifugal fan according to a first aspect of the present invention has a trailing edge portion from which air flows out, and a leading edge portion located closer to the rotation axis than the trailing edge portion and into which air flows in, and comprises a plurality of blade bodies arranged at intervals from each other in the rotational direction, and each of the plurality of blade bodies has a first blade portion including a first plate-shaped portion of approximately constant thickness, a second blade portion located closer to the trailing edge portion than the first blade portion and having a thickness that increases toward the trailing edge portion, a third blade portion located closer to the trailing edge portion than the second blade portion and having a thickness that decreases toward the trailing edge portion, and a fourth blade portion located closer to the trailing edge portion than the third blade portion and including a second plate-shaped portion of approximately constant thickness.

According to the above configuration, the centrifugal fan can reduce separation of the air flow by having the second blade portion and the third blade portion. Furthermore, the centrifugal fan can increase the area of the inlet of the flow path formed between adjacent blade bodies by having the first plate-shaped portion connected to the second blade portion. This reduces separation of the air flow, reduces frictional resistance, and increases the air volume. Therefore, the centrifugal fan can fully demonstrate its capabilities as a fan.

In the centrifugal fan according to aspect 2 of the present invention, in the above aspect 1, each of the plurality of blades may be curved convexly in the opposite direction to the rotation direction.

In the centrifugal fan according to aspect 3 of the present invention, in the above aspect 1 or 2, a plane parallel to the surface of the first plate-shaped portion on the opposite side of the rotation direction may intersect with a plane parallel to the surface of the second plate-shaped portion on the opposite side of the rotation direction.

A centrifugal fan according to aspect 4 of the present invention is any one of aspects 1 to 3 above, in which the first plate-shaped portion and the second plate-shaped portion may be inclined relative to the radial direction.

With the above configuration, the centrifugal fan can blow air efficiently.

The centrifugal fan according to aspect 5 of the present invention is any one of aspects 1 to 4 above, in which the maximum thickness of the second blade portion and the third blade portion may be greater than the maximum thickness of the first blade portion and the maximum thickness of the fourth blade portion.

The above configuration can reduce separation of the air flow.

A centrifugal fan according to aspect 6 of the present invention is any one of aspects 1 to 5 above, in which the second blade portion may be adjacent to the third blade portion.

With the above configuration, where the blade is curved, a portion where the blade is thicker (for example, a portion with a triangular cross section) is formed. This can reduce separation of the air flow from the blade.

In the centrifugal fan according to aspect 7 of the present invention, in the above aspect 6, each of the plurality of blade bodies has a first surface located on the front side in the rotation direction and a second surface located on the rear side in the rotation direction, and the curvature of the first surface at the boundary between the second blade portion and the third blade portion may be smaller than the curvature of the second surface at the boundary between the second blade portion and the third blade portion.

With the above configuration, where the blade is curved, a portion where the blade is thicker (for example, a portion with a triangular cross section) is formed. This can reduce separation of the air flow from the blade.

The centrifugal fan according to aspect 8 of the present invention is any one of aspects 1 to 6 above, in which each of the plurality of blade bodies has a first surface located forward in the direction of rotation, and the first surface of the second blade portion may be located forward in the direction of rotation from a plane extending from the first surface of the first plate-shaped portion.

The above configuration reduces frictional resistance to air flow.

The centrifugal fan according to aspect 9 of the present invention is any one of aspects 1 to 6 and 8 above, in which each of the plurality of blade bodies has a second surface located on the rear side in the rotation direction, and the second surface of the second blade portion may be located forward in the rotation direction of a plane extending from the second surface of the first plate-shaped portion.

The above configuration reduces frictional resistance to air flow.

The centrifugal fan according to aspect 10 of the present invention is any one of aspects 1 to 6 above, in which each of the plurality of blade bodies has a first surface located forward in the direction of rotation, and the first surface of the third blade portion may be located forward in the direction of rotation from a plane extending from the first surface of the second plate-shaped portion.

The above configuration reduces frictional resistance to air flow.

The centrifugal fan according to aspect 11 of the present invention is any one of aspects 1 to 6, 8, and 10 above, in which each of the plurality of blade bodies has a second surface located on the rear side in the rotation direction, and the second surface of the third blade portion may be located forward in the rotation direction of a plane extending from the second surface of the second plate-shaped portion.

The above configuration reduces frictional resistance to air flow.

The centrifugal fan according to aspect 12 of the present invention may be formed from resin in any one of aspects 1 to 11 above.

The mold according to aspect 13 of the present invention is a mold for molding the centrifugal fan described in aspect 12 above.

The blower device according to aspect 14 of the present invention includes a centrifugal fan according to any one of aspects 1 to 12 above, and a drive motor that rotates the centrifugal fan.

The above configuration allows for a blower with high airflow and reduced noise.

The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims. The technical scope of the present invention also includes embodiments obtained by appropriately combining the technical means disclosed in the different embodiments. Furthermore, new technical features can be formed by combining the technical means disclosed in the respective embodiments.

This disclosure includes a technical idea that focuses on the cross-sectional wing structure that generates lift in the wings of birds of prey. In other words, this invention relates to biomimetics.

10 Blower fan 11 Centrifugal fan 11a Outlet section 11b Inlet section 12 Outer casing 13 Disk body 20 Blade body 20a Positive pressure surface (first surface)
20b Negative pressure surface (second surface)
21 First blade portion 21a First plate-shaped portion 21b Front edge portion 22 Second blade portion 23 Third blade portion 24 Fourth blade portion 24a Second plate-shaped portion 24b Rear edge portion 101 Rotary shaft 110 Molding die 112 Movable side die 114 Fixed side die 116 Cavity 120, 150, 213 Blower (blower device)
126 Outer casing 128, 151 Drive motor 129 Casing 129a Guide wall 140 Air purifier (blower)
141 Filter 144 Housing 145 Duct 201 Indoor unit (blower device)
202 Indoor unit main body 203 Air guide plate 214 Heat exchanger 215 First filter 216 Second filter 218 Opening and closing cover

Claims (11)

The rotor blades have a trailing edge portion from which air flows out and a leading edge portion located closer to the rotor shaft than the trailing edge portion and into which air flows in. The rotor blades are provided with a plurality of blades arranged at intervals in a rotational direction that is a circumferential direction of the rotor shaft,
The blade body is
A first blade portion, the end portion on the trailing edge side being a first plate-shaped portion having a constant thickness;
a second blade portion located closer to the trailing edge portion than the first blade portion, connected to the first plate portion at an end on the leading edge portion side, and having a thickness increasing toward the trailing edge portion;
a third blade portion located closer to the trailing edge portion than the second blade portion and having a thickness that decreases toward the trailing edge portion;
a fourth blade portion located closer to the trailing edge portion than the third blade portion and including a second plate-shaped portion having a constant thickness;
When viewed from the axial direction of the rotation shaft, a boundary between the second blade portion and the third blade portion is curved in a convex shape toward a rear side in the rotation direction,
When a surface of the blade body located on the front side in the rotation direction is defined as a first surface, and a surface of the blade body located on the rear side, which is opposite to the front side in the rotation direction, is defined as a second surface,
The first surface of the second blade portion is a curved surface,
the first surface of the second blade portion and the first surface of the third blade portion are located forward in the rotation direction from a plane extending from the first surface of the first plate-shaped portion,
The second blade portion is
a first portion located at an end of the second blade portion on the leading edge side and connected to the first plate portion ;
a second portion located at an end portion of the second blade portion on the trailing edge side and connected to the boundary ;
a third portion connecting the first portion and the second portion ,
the second surface of the third portion is a curved surface having a smaller curvature than the first surface of the third portion,
A centrifugal fan, wherein the second surface of the second portion is a curved surface having a greater curvature than the first surface of the second portion. a plane parallel to a surface of the first plate-shaped portion opposite to the rotation direction intersects with a plane parallel to a surface of the second plate-shaped portion opposite to the rotation direction,
The angle on the rotational direction side at the intersection between a plane parallel to the surface of the first plate-shaped portion on the rotational direction side and a plane parallel to the surface of the second plate-shaped portion on the rotational direction side is 80° to 110°,
2. The centrifugal fan according to claim 1, wherein an angle on the rotational direction side at an intersection between a plane parallel to a surface of the first plate-shaped portion on the opposite side in the rotational direction and a plane parallel to a surface of the second plate-shaped portion on the opposite side in the rotational direction is 80° to 110°. The centrifugal fan according to claim 1 or 2, wherein the maximum thickness of the second blade portion and the third blade portion is greater than the maximum thickness of the first blade portion and the maximum thickness of the fourth blade portion. The centrifugal fan according to any one of claims 1 to 3, wherein the second blade portion is adjacent to the third blade portion. The centrifugal fan according to claim 4, wherein the curvature of the boundary between the second blade portion and the third blade portion of the first surface is smaller than the curvature of the boundary between the second blade portion and the third blade portion of the second surface. The centrifugal fan according to claim 1 , wherein the second surface of the second blade portion is located forward in the rotation direction of a plane extending from the second surface of the first plate-shaped portion. 5 . The centrifugal fan according to claim 1 , wherein the second surface of the third blade portion is located forward in the rotation direction of a plane extending from the second surface of the second plate-shaped portion. The centrifugal fan according to claim 1 , wherein the centrifugal fan is made of resin. A mold for molding the centrifugal fan according to claim 8 . A centrifugal fan according to any one of claims 1 to 8 ;
and a drive motor that rotates the centrifugal fan. The rotor blades have a trailing edge portion from which air flows out and a leading edge portion located closer to the rotor shaft than the trailing edge portion and into which air flows in. The rotor blades are provided with a plurality of blades arranged at intervals in a rotational direction that is a circumferential direction of the rotor shaft,
The blade body is
A first blade portion, the end portion on the trailing edge side being a first plate-shaped portion having a constant thickness;
a second blade portion located closer to the trailing edge portion than the first blade portion, connected to the first plate portion at an end on the leading edge portion side, and having a thickness increasing toward the trailing edge portion;
a third blade portion located closer to the trailing edge portion than the second blade portion and having a thickness that decreases toward the trailing edge portion,
When viewed from the axial direction of the rotation shaft, a boundary between the second blade portion and the third blade portion is curved in a convex shape toward a rear side in the rotation direction,
When a surface of the blade body located on the front side in the rotation direction is defined as a first surface, and a surface of the blade body located on the rear side, which is opposite to the front side in the rotation direction, is defined as a second surface,
The first surface of the second blade portion is a curved surface,
the first surface of the second blade portion and the first surface of the third blade portion are located forward in the rotation direction from a plane extending from the first surface of the first plate-shaped portion,
The second blade portion is
a first portion located at an end of the second blade portion on the leading edge side and connected to the first plate portion ;
a second portion located at an end portion of the second blade portion on the trailing edge side and connected to the boundary ;
a third portion connecting the first portion and the second portion ,
the second surface of the third portion is a curved surface having a smaller curvature than the first surface of the third portion,
A centrifugal fan, wherein the second surface of the second portion is a curved surface having a greater curvature than the first surface of the second portion.

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