WO2023032762A1 - Centrifugal fan - Google Patents

Abstract

This centrifugal fan rotates around the fan axial center (CL) thereof and thereby suctions air from one side in the axial direction (Da) of the fan axial center and blows the suctioned air toward the outside in the radial direction (Dr) of the fan axial center. The centrifugal fan comprises a plurality of blades (32), a side plate (34), and a main plate (36, 43, 401). The plurality of blades are disposed side-by-side around the fan axial center and have a blade rear edge (324) at the outside thereof in the radial direction. The side plate has formed therein an air suction hole (34a) into which air is suctioned, and the side plate is provided at one side in the axial direction relative to the plurality of blades and is linked to each of the plurality of blades. The main plate is linked to each of the plurality of blades at the side opposite of the side plate and widens in the radial direction. In addition: where the inner diameter of the side plate is Dsi and the outer diameter of the side plate is Dso, the relationship Dsi/Dso is 0.5 < Dsi/Dso < 0.7; and the blade rear edges are formed so as to be located further inward in the radial direction the further toward the one side in the axial direction.

Description

centrifugal fan Cross-references to related applications

This application is based on Japanese Patent Application No. 2021-143526 filed on September 2, 2021 and Japanese Patent Application No. 2022-86280 filed on May 26, 2022, hereby The contents of which are incorporated by reference.

The present disclosure relates to a centrifugal fan that causes air to flow by rotating.

The centrifugal fan described in Patent Document 1 includes a plurality of three-dimensional blades (that is, blades), a main plate, and side plates. One spanwise end face of each blade is fixed to the main plate, and the other spanwise end face of each blade is fixed to the side plate.
In addition, in the three-dimensional blade, the main stream of the intake air flow does not follow the side plate and is blown off to the main plate side, and the intake air flow has a biased velocity distribution and noise is generated. Document 1 shows this as a problem.

On the other hand, in the centrifugal fan of Patent Document 1, each blade is formed so that the diameter of the trailing edge portion of the blade is larger on the main plate side than on the side plate side. Patent Document 1 describes that this improves the distribution of the mainstream velocity between the blades and reduces the noise.

WO2009/139422

In general, for a centrifugal fan, the ratio of fan inner and outer diameters is the ratio obtained by dividing the suction diameter, which is the inner diameter of the side plate (i.e., the diameter of the intake hole of the centrifugal fan), by the outlet diameter (i.e., the outer diameter of the side plate). are assumed to vary. However, Patent Document 1 does not mention the fan inner/outer diameter ratio.

In addition, the smaller the fan inner/outer diameter ratio, the longer the air flow path formed between the blades (in other words, the inter-blade flow path). , an air flow that is not described in Patent Document 1 is generated in the inter-blade flow path.

Specifically, the air flow in the inter-blade passage separates from the back surface of the side plate (i.e., the blade-side surface of the side plate) near the intake holes and is once biased toward the main plate. Flow to reattach. Therefore, at the outlet of the inter-blade passage, the air flow is biased toward the side plate, and the air flow velocity distribution is biased to one side in the axial direction of the fan. Then, noise is generated due to the biased airflow velocity distribution near the exit of the inter-blade passage. The inventors have newly discovered this fact.

In view of the above points, an object of the present disclosure is to provide a centrifugal fan capable of suppressing noise caused by uneven velocity distribution of airflow near the outlet of the inter-blade passage.

In order to achieve the above object, according to one aspect of the present disclosure, a centrifugal fan
A centrifugal fan that rotates around the fan axis to suck air from one side in the axial direction of the fan axis and blow the sucked air outward in the radial direction of the fan axis,
a plurality of blades arranged side by side around the fan axis and having blade trailing edges radially outward;
a side plate provided on one side in the axial direction with respect to the plurality of blades and connected to each of the plurality of blades;
A main plate connected to each of the plurality of blades on the side opposite to the side plate side and extending in the radial direction,
When the inner diameter of the side plate is Dsi and the outer diameter of the side plate is Dso, Dsi/Dso is 0.5<Dsi/Dso<0.7,
The trailing edge portion of the blade is formed so as to be located radially inward toward one side in the axial direction.

Here, as described above, in the inter-blade passages, which are the air passages formed between the blades, the air flows along one side in the axial direction so as to once separate from the side plates and then reattach to the side plates. biased. On the other hand, in the centrifugal fan described above, since the trailing edge of the blades is positioned radially inward toward one side in the axial direction, the amount of work performed by each blade on the main plate side is compared to that on the side plate side. , and the air flow can be drawn toward the main plate again in the vicinity of the exit of the interblade passage. As a result, compared to the case where the trailing edge of the blade is parallel to the fan axis, for example, the air flow velocity distribution near the outlet of the inter-blade passage can be brought closer to a distribution free from axial bias, It is possible to reduce the noise of the centrifugal fan.

In the above centrifugal fan, Dsi/Dso satisfies 0.5<Dsi/Dso<0.7, where Dsi is the inner diameter of the side plate and Dso is the outer diameter of the side plate. Therefore, if the blade trailing edge is parallel to the fan axis, the air flow in the inter-blade passage is biased toward the side plate near the exit of the inter-blade passage. It is possible to use the above-described configuration in which the side is located radially inward. Therefore, it is possible to use the configuration of the blade trailing edge so as to appropriately reduce the noise of the centrifugal fan.

It should be noted that the reference numerals in parentheses attached to each component etc. indicate an example of the correspondence relationship between the component etc. and the specific component etc. described in the embodiment described later.

It is a perspective view showing the appearance of an air blower in a 1st embodiment. FIG. 2 is a vertical cross-sectional view showing the blower cut along a plane including the fan axis in the first embodiment, that is, a cross-sectional view schematically showing the II-II cross section of FIG. 1; FIG. 3 is a plan view showing a centrifugal fan and a rotating shaft of the blower in the first embodiment, viewed from one side to the other side in the axial direction of the fan. 3 is a cross-sectional view showing the same cross section as FIG. 2; FIG. FIG. 2 is a perspective view showing a trailing edge of the blade of the centrifugal fan and its surroundings in the first embodiment. FIG. 2 is a cross-sectional view showing a cross section obtained by cutting a trailing edge portion of the blade of the centrifugal fan and its periphery along a plane perpendicular to the fan axis in the first embodiment; FIG. 4A is a cross-sectional view of a portion connected to a side plate, and FIG. 4B is a cross-sectional view of a portion of a blade trailing edge portion connected to a main plate. FIG. 4 is a diagram showing the analysis results of a CFD simulation for confirming the effects in the first embodiment, showing the speed of the airflow in the inter-blade passage obtained in the case of "Dsi/Dso=0.72" It is the figure which showed distribution. FIG. 7B is a diagram showing the analysis results of the CFD simulation in the same manner as FIG. 7A, and showing the velocity distribution of the airflow in the inter-blade passage obtained in the case of "Dsi/Dso=0.68". . FIG. 7B is a diagram showing the analysis results of the simulation by CFD in the same manner as FIG. 7A, and is a diagram showing the velocity distribution of the airflow in the inter-blade passage obtained in the case of "Dsi/Dso=0.55". . FIG. 7B is a diagram showing the analysis results of the CFD simulation in the same manner as FIG. 7A, and showing the velocity distribution of the airflow in the inter-blade passage obtained in the case of "Dsi/Dso=0.48". . FIG. 3 is a diagram in which the SPL of noise generated by the fan of the first embodiment is indicated by a solid line S1, and the SPL of noise generated by the fan of a comparative example is indicated by a dashed line S2. FIG. 5 is a diagram comparing the noise generated by the blower of the first embodiment and the noise generated by the blower of the comparative example in terms of overall values; FIG. 4 is a graph showing the relationship between Dmo/Db2, which is the ratio of the outer diameter Dmo of the main plate to the other diameter Db2 of the trailing edge portion of the blade, and the noise reduction effect in the first embodiment. FIG. 3 is a longitudinal cross-sectional view schematically showing the blower cut along a plane including the fan axis in the second embodiment, and corresponding to FIG. 2 ; FIG. 10 is a vertical cross-sectional view schematically showing the blower cut along a plane including the fan axis in the third embodiment, and corresponding to FIG. 2 ; FIG. 10 is a longitudinal sectional view schematically showing the blower cut along a plane including the fan axis in the fourth embodiment, corresponding to FIG. 2 ; FIG. 11 is a longitudinal sectional view schematically showing the blower cut along a plane including the fan axis in the fifth embodiment, corresponding to FIG. 2 ; FIG. 12 is a longitudinal sectional view schematically showing the blower cut along a plane including the fan axis in the sixth embodiment, corresponding to FIG. 2 ; FIG. 12 is a longitudinal sectional view schematically showing the blower cut along a plane including the fan axis in the seventh embodiment, corresponding to FIG. 2 ; In the eighth embodiment, it is a vertical cross-sectional view schematically showing the blower cut along a plane including the fan axis, and corresponding to FIG. 2 . In the ninth embodiment, it is a vertical cross-sectional view schematically showing the blower cut along a plane including the fan axis, and corresponding to FIG. 2 . In the tenth embodiment, it is a vertical cross-sectional view schematically showing the blower cut along a plane including the fan axis, and corresponding to FIG. 2 .

Each embodiment will be described below with reference to the drawings. In addition, in each of the following embodiments, the same or equivalent portions are denoted by the same reference numerals in the drawings.

(First embodiment)
As shown in FIGS. 1 and 2, the blower 10 of this embodiment is a centrifugal blower, more specifically a turbo blower. The blower 10 includes a casing 12 which is a housing of the blower 10, a rotary shaft 14, an electric motor 16, an electronic substrate 17, a centrifugal fan 18, a bearing 28, a bearing housing 29, and the like.

Note that the fan axis CL shown in FIG. 2 is the center of rotation of the centrifugal fan 18 . An arrow Da in FIG. 2 indicates the axial direction Da of the fan axis CL, that is, the fan axis direction Da. An arrow Dr in FIG. 2 indicates the radial direction Dr of the fan axis CL, that is, the fan radial direction Dr. In addition, in FIG. 2 and the figures corresponding to FIG. 2 to be described later, the illustration of the right side of the fan 10 with respect to the fan axis CL is omitted.

The casing 12 protects the electric motor 16, the electronic board 17, and the centrifugal fan 18 from dust and dirt outside the blower 10. For this purpose, casing 12 houses electric motor 16 , electronic board 17 , and centrifugal fan 18 . Also, the casing 12 is composed of a first case member 22 and a second case member 24 . The casing 12 is a non-rotating member of the blower 10 .

The first case member 22 of the casing 12 is made of, for example, resin, has a larger diameter than the centrifugal fan 18, and has a substantially disk shape. The first case member 22 is composed of a first cover portion 221 , a first case outer peripheral portion 222 , a first peripheral edge portion 223 and a plurality of struts 224 .

The first case member 22 is a cover that covers the centrifugal fan 18 on one side of the centrifugal fan 18 in the fan axial direction Da. Therefore, the first case member 22 is provided on the side opposite to the blade 32 side with respect to the side plate 34 of the centrifugal fan 18 . Further, since the centrifugal fan 18 rotates with respect to the casing 12, the first case member 22 is arranged away from the side plate 34 of the centrifugal fan 18 in order to prevent mutual interference. The first case member 22 corresponds to the side plate adjacent case of the present disclosure.

The first cover portion 221 of the first case member 22 has a shape expanding in the fan radial direction Dr. The first cover portion 221 is arranged on one side of the centrifugal fan 18 in the fan axial direction Da and covers the one side of the centrifugal fan 18 in the fan axial direction Da.

An air intake port 221a is formed on the inner peripheral side of the first cover portion 221 and extends through the first cover portion 221 in the fan axial direction Da. sucked into. Further, the first cover portion 221 has an intake port forming portion 221b provided as a bell mouth forming the periphery of the air intake port 221a. The suction port forming portion 221b forms an air suction port 221a inside the suction port forming portion 221b, and smoothly guides the air flowing into the air suction port 221a from the outside of the blower 10 into the air suction port 221a.

The first case outer peripheral portion 222 of the first case member 22 is arranged outside the first cover portion 221 in the fan radial direction Dr and is connected to the first cover portion 221 . The first case outer peripheral portion 222 is arranged outside the side plate 34 of the centrifugal fan 18 in the fan radial direction Dr. The first case perimeter 222 corresponds to the case perimeter of the present disclosure.

As shown in FIGS. 1 and 2 , the first peripheral edge portion 223 of the first case member 22 is provided outside the first case outer peripheral portion 222 in the fan radial direction Dr, and extends around the fan axial center CL. It constitutes the periphery of the member 22 .

A plurality of struts 224 of the first case member 22 each protrude from the first case outer peripheral portion 222 toward the inside of the casing 12 in parallel with the fan axis CL. Also, the strut 224 has a thick cylindrical shape with a central axis parallel to the fan axis CL. A screw hole through which a screw 26 that joins the first case member 22 and the second case member 24 is inserted is formed inside the support 224 .

Each strut 224 of the first case member 22 is arranged outside the centrifugal fan 18 in the fan radial direction Dr. The first case member 22 and the second case member 24 are connected by screws 26 inserted through the support 224 with the tip of the support 224 abutting against the second case member 24 .

The second case member 24 has a substantially disk shape with substantially the same diameter as the first case member 22 . The second case member 24 is made of metal such as iron or stainless steel or resin, and functions also as a motor housing that covers the electric motor 16 and the electronic substrate 17 . The second case member 24 is composed of a second cover portion 241 , a second case outer peripheral portion 242 and a second peripheral edge portion 243 .

The second cover portion 241 is arranged on the other side in the fan axial direction Da with respect to the centrifugal fan 18 and the electric motor 16, and covers the other side of the centrifugal fan 18 and the electric motor 16 in the fan axial direction Da.

The second case outer peripheral portion 242 of the second case member 24 is arranged outside the second cover portion 241 in the fan radial direction Dr and is connected to the second cover portion 241 . The second case outer peripheral portion 242 is arranged outside the main plate 36 of the centrifugal fan 18 in the fan radial direction Dr.

The second case outer peripheral portion 242 and the first case outer peripheral portion 222 are formed so as to face each other in the fan axial direction Da. Between the second case outer peripheral portion 242 and the first case outer peripheral portion 222, a fan outer peripheral flow path 12b is formed to flow the air blown out from the outlet 18a of the centrifugal fan 18 to the outside in the fan radial direction Dr. . The fan outer peripheral flow path 12b is formed over the entire circumference of the centrifugal fan 18. As shown in FIG.

The second peripheral edge portion 243 of the second case member 24 is provided outside the second case outer peripheral portion 242 in the fan radial direction Dr, and constitutes the peripheral edge of the second case member 24 around the fan axis CL.

The first peripheral edge portion 223 and the second peripheral edge portion 243 constitute an air blowing portion for blowing air in the casing 12 . In addition, the first peripheral edge portion 223 and the second peripheral edge portion 243 are provided between the first peripheral edge portion 223 and the second peripheral edge portion 243 in the fan axial direction Da, and the air outlet 12a through which the air blown out from the centrifugal fan 18 is blown out. forming The air outlet 12a is also the downstream end of the fan outer peripheral channel 12b.

Specifically, the air outlet 12a is formed on the side surface of the fan of the blower 10 and opens outward in the fan radial direction Dr. The air outlet 12a is open over the entire circumference of the casing 12 around the fan axis CL, and blows out the air from the centrifugal fan 18. As shown in FIG. That is, the blower 10 is an all-around blower in which the air outlet 12a is provided over the entire circumference of the casing 12 . It should be noted that, at a location where the strut 224 is provided, the blowing of air from the casing 12 is blocked by the strut 224. It is a meaning including opening.

The rotating shaft 14 is made of metal such as iron, stainless steel, or brass. The rotating shaft 14 is a columnar bar as shown in FIG. 2, and is press-fitted into the inner ring of the bearing 28, for example. Therefore, the rotating shaft 14 is fixed with respect to the inner ring of the bearing 28 . Also, the outer ring of the bearing 28 is fixed to the bearing housing 29 by, for example, being press-fitted. The bearing housing 29 is made of metal such as aluminum alloy, brass, iron, or stainless steel, and is fixed to the second cover portion 241 .

Therefore, the rotating shaft 14 is supported by the second cover portion 241 via the bearings 28 . That is, the rotary shaft 14 is rotatable about the fan axis CL with respect to the second cover portion 241 .

At the same time, one end of the rotating shaft 14 in the fan axial direction Da is fitted into the inner peripheral hole 36 a of the main plate 36 of the centrifugal fan 18 . fixed against. That is, the centrifugal fan 18 rotates integrally with the rotary shaft 14 around the fan axis CL.

The electric motor 16 is an outer rotor type brushless DC motor. The electric motor 16 is arranged together with the electronic board 17 between the main plate 36 of the centrifugal fan 18 and the second cover portion 241 in the fan axial direction Da. The electric motor 16 has a motor rotor 161 , a rotor magnet 162 and a motor stator 163 . The motor rotor 161 is made of metal such as a steel plate, and is formed, for example, by press forming the steel plate.

The rotor magnet 162 is a permanent magnet, and is composed of, for example, a rubber magnet containing ferrite, neodymium, or the like. The rotor magnet 162 is integrally fixed to the motor rotor 161 . Also, the motor rotor 161 is fixed to the rotor connecting portion 38 of the centrifugal fan 18 . That is, the motor rotor 161 and the rotor magnet 162 rotate integrally with the centrifugal fan 18 about the fan axis CL.

The motor stator 163 includes a stator coil 163a and a stator core 163b electrically connected to the electronic board 17. The motor stator 163 is arranged radially inside the rotor magnet 162 with a small gap therebetween. The motor stator 163 is fixed to the second cover portion 241 of the second case member 24 via the bearing housing 29 . A plurality of electric components (not shown) are mounted on the electronic board 17 . For example, an electric circuit for rotating the electric motor 16 is configured on the electronic board 17 .

In the electric motor 16 configured in this way, when the stator coil 163a of the motor stator 163 is energized from an external power supply, the stator coil 163a causes a magnetic flux change in the stator core 163b. A magnetic flux change in the stator core 163 b generates a force that attracts the rotor magnet 162 . Since the motor rotor 161 is fixed to the rotating shaft 14 rotatably supported by the bearing 28, it rotates around the fan axis CL under the force of attracting the rotor magnet 162. As shown in FIG. In short, when the electric motor 16 is energized, it rotates the centrifugal fan 18 to which the motor rotor 161 is fixed around the fan axis CL.

The centrifugal fan 18 is an impeller applied to the blower 10, as shown in FIGS. The centrifugal fan 18 blows air by rotating around the fan axis CL in a predetermined fan rotation direction DRf. That is, the centrifugal fan 18 rotates around the fan axis CL to draw air from one side in the fan axis direction Da through the air intake port 221a as indicated by the arrow FLa. Then, the centrifugal fan 18 blows out the sucked air radially outward of the centrifugal fan 18 as indicated by an arrow FLb.

Specifically, the centrifugal fan 18 of this embodiment is a turbo fan. The centrifugal fan 18 has a plurality of blades 32 , side plates 34 , main plates 36 and rotor connecting portions 38 . The centrifugal fan 18 is made of resin, for example, and its plurality of blades 32, side plates 34, main plate 36, and rotor connecting portion 38 are integrally constructed.

A plurality of blades 32 are arranged around the fan axis CL. Specifically, the plurality of blades 32 are arranged side by side in the circumferential direction Dc of the fan axial center CL while leaving an interval for air flow between them. Airfoils 32 are also referred to as fan blades.

The blades 32 are provided on one side of the blades 32 in the fan axial direction Da, and on the other side of the blades 32 opposite to the one side in the fan axial direction Da. and a wing other end portion 322 which is closed. The plurality of blades 32 form inter-blade passages 32a through which air flows between adjacent blades 32 among the plurality of blades 32 .

As shown in FIGS. 2 and 3, the side plate 34 has a disk shape that expands in the fan radial direction Dr. An air intake hole 34a through which air from the air intake port 221a of the casing 12 is sucked as indicated by an arrow FLa is formed inside the side plate 34 in the radial direction. Therefore, the side plate 34 has an annular shape around the fan axis CL.

In addition, the side plate 34 has a side plate inner peripheral end portion 341 and a side plate outer peripheral end portion 342 . The side plate inner peripheral end portion 341 is an end portion provided inside the side plate 34 in the fan radial direction Dr, and forms the intake hole 34a. The side plate outer peripheral end portion 342 is an end portion of the side plate 34 provided on the outside in the fan radial direction Dr. The side plate outer peripheral edge 342 corresponds to the outer peripheral edge of the present disclosure that the side plate 34 has.

Also, the side plate 34 is provided on one side of the plurality of blades 32 in the fan axial direction Da, that is, on the side of the air intake port 221a. Along with that, the side plate 34 is connected to each of the plurality of wings 32 . In other words, the side plate 34 is connected to each of its blades 32 at one blade end 321 .

The side plate 34 also has a side plate other surface 343 facing the other side in the fan axial direction Da. This side plate other surface 343 faces the inter-blade flow path 32 a and guides the airflow inside the centrifugal fan 18 . The side plate other surface 343 is a curved surface that expands in the fan radial direction Dr, and is located on the other side in the fan axial direction Da toward the outside in the fan radial direction Dr. 2, which is a longitudinal section including the fan axis CL, the radius of curvature of the side plate other surface 343 increases toward the outer side in the fan radial direction Dr.

For example, in this embodiment, in the vertical cross section of the fan 10 shown in FIG. 2, the side plate other surface 343 has an inner arc shape 343a, an outer arc shape 343b, and an outer linear shape 343c. The inner arc shape 343a, the outer arc shape 343b, and the outer linear shape 343c are smoothly connected in the order of the inner arc shape 343a, the outer arc shape 343b, and the outer linear shape 343c from the inside in the fan radial direction Dr. The curvature radius R2 of the outer arcuate shape 343b is larger than the curvature radius R1 of the inner arcuate shape 343a, and the outer linear shape 343c is linear perpendicular to the fan axis CL.

Since the main plate 36 is fixed to the rotating shaft 14 rotatable around the fan axis CL, it is supported rotatably around the fan axis CL with respect to the casing 12 . The main plate 36 has a disk-like shape extending in the fan radial direction Dr around the fan axis CL.

Also, the main plate 36 is connected to each of the plurality of blades 32 on the side opposite to the side plate 34 side. That is, the main plate 36 is connected to each of the plurality of blades 32 at the blade other end portion 322 .

The main plate 36 also has a main plate guide surface 36b that guides the airflow inside the centrifugal fan 18. The main plate guide surface 36b faces the inter-blade passage 32a and faces the other side plate surface 343 across the inter-blade passage 32a. The main plate guide surface 36b is a curved surface that faces one side in the fan axial direction Da and expands in the fan radial direction Dr, and is located on the other side in the fan axial direction Da toward the outside in the fan radial direction Dr. formed. With such a shape, the main plate guide surface 36b guides the airflow sucked into the air inlet 221a and directed in the fan axial direction Da so as to be directed outward in the fan radial direction Dr.

Further, in order to fix the main plate 36 to the rotating shaft 14, an inner peripheral hole 36a is formed radially inside the main plate 36 so as to penetrate the main plate 36 in the fan axial direction Da.

The rotor connecting portion 38 is a cylindrical rib centered on the fan axis CL, and protrudes from the main plate 36 to the other side in the fan axis direction Da. A motor rotor 161 is fitted and stored inside the rotor connecting portion 38 in the radial direction. Thereby, the rotor connecting portion 38 is fixed to the motor rotor 161 . By fixing the rotor connecting portion 38 to the motor rotor 161 , the centrifugal fan 18 is fixed to the motor rotor 161 .

In addition, the main plate 36 has a main plate outer peripheral end portion 362 . The main plate outer peripheral end portion 362 is an end portion of the main plate 36 provided outside in the fan radial direction Dr. The main plate outer peripheral end portion 362 and the side plate outer peripheral end portion 342 are arranged apart from each other in the fan axial direction Da. The main plate outer peripheral end portion 362 and the side plate outer peripheral end portion 342 form the outlet 18a from which the air that has passed through the inter-blade passage 32a is blown out between the main plate outer peripheral end portion 362 and the side plate outer peripheral end portion 342. there is That is, the main plate outer peripheral end portion 362 and the side plate outer peripheral end portion 342 constitute an air blowing portion of the centrifugal fan 18 in which the blowing port 18a is formed. The blowout port 18a of the centrifugal fan 18 faces outward in the fan radial direction Dr and is formed along the entire circumference of the centrifugal fan 18 around the fan axis CL.

In this embodiment, the position of the main plate outer peripheral end portion 362 in the fan radial direction Dr is aligned with the position of the side plate outer peripheral end portion 342 . That is, as shown in FIGS. 2 and 4, the outer diameter Dmo of the main plate 36 and the outer diameter Dso of the side plate 34 are the same size, which is the outer diameter Dout of the centrifugal fan 18 .

The side plate inner/outer diameter ratio, which is the ratio of the inner diameter Dsi of the side plate 34 to the outer diameter Dso of the side plate 34, is calculated by Dsi/Dso. 0.7". Specifically, in this embodiment, the Dsi/Dso is "Dsi/Dso=0.55". In other words, the inner diameter Dsi of the side plate 34 is also the diameter of the intake hole 34 a formed in the side plate 34 .

As shown in FIGS. 2 and 4, each of the plurality of blades 32 has a blade leading edge portion 323 provided on the inner side in the fan radial direction Dr and a blade trailing edge portion 324 provided on the outer side in the fan radial direction Dr. and The leading edge portion 323 of the blade is an edge portion formed on the upstream side in the airflow direction of the air passing through the intake hole 34a and flowing into the inter-blade passage 32a. The blade trailing edge portion 324 is an edge portion formed on the downstream side of the blade 32 in the airflow direction of the air flowing through the inter-blade passage 32a.

The blade leading edge portion 323 is connected to the side plate 34 and the main plate 36 and extends from the side plate 34 side to the main plate 36 side. A blade trailing edge 324 is also connected to the side plate 34 and the main plate 36 and extends from the side plate 34 side to the main plate 36 side.

The blade leading edge portion 323 is formed so as to be located inside in the fan radial direction Dr toward the main plate 36 side. Specifically, the blade leading edge portion 323 includes a first leading edge portion 323a and a second leading edge portion 323b. The first front edge portion 323a and the second front edge portion 323b are formed to extend linearly, and the first front edge portion 323a and the second front edge portion 323b are connected in series. The first front edge portion 323 a is connected to the side plate 34 . The second front edge portion 323 b is connected to the main plate 36 and provided between the first front edge portion 323 a and the main plate 36 .

Also, the angle formed by the second front edge portion 323b with respect to the fan axis CL is smaller than the angle formed with the first front edge portion 323a with respect to the fan axis CL. Specifically, in the vertical cross sections of FIGS. 2 and 4, the first front edge portion 323a extends linearly in a direction perpendicular to the fan axis CL. Further, the second front edge portion 323b extends linearly while being inclined with respect to the fan axis CL so as to be located outside in the fan radial direction Dr toward one side in the fan axis direction Da.

Therefore, the one-side diameter Df1 of the second front edge portion 323b is larger than the other-side diameter Df2 of the second front edge portion 323b. The one-side diameter Df1 of the second front edge portion 323b is a diameter around the fan axis CL that the second front edge portion 323b has at one end in the fan axis direction Da. The other side diameter Df2 of the second front edge portion 323b is a diameter centered on the fan axis CL that the second front edge portion 323b has at the other side end in the fan axis direction Da.

The trailing edge portion 324 of the blade extends toward the inside in the fan radial direction Dr toward one side in the fan axial direction Da. Specifically, in the vertical cross sections of FIGS. 2 and 4, the blade trailing edge portion 324 is inclined with respect to the fan axis CL such that the side plate 34 side is located inside the main plate 36 side in the fan radial direction Dr. It is formed linearly.

Therefore, the one side diameter Db1 of the blade trailing edge portion 324 is smaller than the other side diameter Db2 of the blade trailing edge portion 324. The one-side diameter Db1 of the blade trailing edge portion 324 is the diameter of the blade trailing edge portion 324 at one end in the fan axial direction Da centered on the fan axial center CL. Further, the other side diameter Db2 of the blade trailing edge portion 324 is a diameter around the fan axis CL that the blade trailing edge portion 324 has at the other side end in the fan axis direction Da.

As shown in FIGS. 2 and 4, the other side diameter Db2 of the blade trailing edge portion 324 is also the maximum outer diameter of the blade 32 around the fan axis CL. Between the other side diameter Db2 of the blade trailing edge portion 324 and the outer diameter Dmo of the main plate 36, a relationship of "Db2<Dmo≦1.13×Db2" is established. Specifically, in this embodiment, the relationship between the other side diameter Db2 of the blade trailing edge portion 324 and the outer diameter Dmo of the main plate 36 is "Dmo=1.06×Db2".

Also, as shown in FIGS. 2 and 4, part of the blade leading edge 323 falls within an axial range Hb1 included in the full width Hb of the blade trailing edge 324 in the fan axial direction Da. The portion of the blade leading edge portion 323 within the axial range Hb1 is, in detail, a portion of the second leading edge portion 323b including the end on the main plate 36 side.

A portion Psi of the side plate other surface 343 that starts expanding outward in the fan radial direction Dr from the side plate inner peripheral end portion 341 has an axial height H2 along the fan axial direction Da with respect to the main plate guide surface 36b, The outer diameter Dso has a relationship of "0.06<H2/Dso<0.20". Specifically, in this embodiment, the H2/Dso is "H2/Dso=0.082".

Further, in the centrifugal fan 18 of the present embodiment, the blade trailing edge portion 324 is connected to the side plate 34 inside the side plate outer peripheral end portion 342 in the fan radial direction Dr. At the same time, the blade trailing edge portion 324 is connected to the main plate 36 inside the main plate outer peripheral end portion 362 in the fan radial direction Dr. That is, the side plate 34 and the main plate 36 each extend outside the blade trailing edge portion 324 in the fan radial direction Dr. Specifically, the size relationship between the outer diameter Dso of the side plate 34 and the one-side diameter Db1 of the blade trailing edge portion 324 is "Dso>Db1". The size relationship with the other side diameter Db2 is "Dmo>Db2".

As described above, since the first case member 22 is arranged away from the side plate 34 of the centrifugal fan 18, the side plate 34 forms a case side plate clearance 34b between itself and the first case member 22. For example, the case side plate gap 34b is formed to be as narrow a gap as possible within a range where interference between the first case member 22 and the centrifugal fan 18 can be prevented.

Further, the first case outer peripheral portion 222 extends from the first cover portion 221 and is provided so as to overlap the side plate outer peripheral end portion 342 on the outside in the fan radial direction Dr. The inner diameter Dc1 of the first case outer peripheral portion 222 is larger than the outer diameter Dso of the side plate 34 . Therefore, the side plate outer peripheral end portion 342 faces the first case outer peripheral portion 222 in the fan radial direction Dr, and forms an opening end 34c of the case side plate gap 34b between the first case outer peripheral portion 222 and the first case outer peripheral portion 222 . An open end 34c of the case side plate gap 34b is located inside the fan radial direction Dr from the air outlet 12a of the casing 12, and the case side plate gap 34b is connected to the fan outer peripheral flow path 12b at the open end 34c.

In this embodiment, as shown in FIGS. 5 and 6, the thickness tb of the blade 32 is not constant at the blade trailing edge portion 324 . Specifically, the thickness tb of the blade 32 increases toward the side plate 34 at the blade trailing edge portion 324 . For example, the side plate side trailing edge thickness tb1, which is the thickness tb of the blade 32 at the portion of the blade trailing edge portion 324 connected to the side plate 34, is the thickness of the blade 32 at the portion of the blade trailing edge portion 324 connected to the main plate 36. It is larger than the main plate side trailing edge thickness tb2, which is the thickness tb.

Since the thickness tb of the blade 32 at the blade trailing edge portion 324 changes according to the axial position, the surface shape of the blade trailing edge portion 324 also changes according to the axial position. ing. In addition, in FIG. 6, the air flow around the blade 32 is represented by a dashed line.

Specifically, as shown in FIG. 6 , the blade trailing edge 324 has a trailing edge outer surface 324 a that is the surface of the blade trailing edge 324 . A trailing edge outer surface 324a connects the pressure surface and the suction surface of the blade 32 at the blade trailing edge 324, and is convexly curved in a cross section perpendicular to the fan axis CL. Furthermore, in its cross section, the radius of curvature Rb of the rear edge portion outer surface 324a increases toward the side plate 34 side. For example, the side plate side curvature radius Rb1, which is the curvature radius Rb of the trailing edge outer surface 324a at the portion of the blade trailing edge portion 324 connected to the side plate 34, is the radius of curvature Rb1 at the portion of the blade trailing edge portion 324 connected to the main plate 36. It is larger than the main plate side curvature radius Rb2, which is the curvature radius Rb.

In FIG. 5, the blade trailing edge portion 91 of the centrifugal fan of the comparative example compared with the present embodiment is indicated by broken lines. In the centrifugal fan of the comparative example, the trailing edge portion 91 of the blade is parallel to the fan axis CL, and the thickness tb of the blade 32 at the trailing edge portion 91 of the blade is constant. Except for these points, the centrifugal fan of the comparative example is the same as the centrifugal fan 18 of this embodiment.

The centrifugal fan 18 configured as described above rotates integrally with the motor rotor 161 in the fan rotation direction DRf as shown in FIGS. Along with this, the blades 32 of the centrifugal fan 18 give momentum to the air, so the centrifugal fan 18 sucks air from the intake holes 34a as indicated by the arrow FLa, and the sucked air flows as indicated by the arrows FL1, FL2, and FL3. flows radially outward through the inter-blade passage 32a. Then, the centrifugal fan 18 blows out the air that has passed through the inter-blade passage 32a radially outward from the outlet 18a as indicated by an arrow FLb. The air blown out from the blowout port 18a passes through the fan outer peripheral flow path 12b of the casing 12 and is discharged to the outside of the blower 10 from the air blowout port 12a.

As described above, according to the present embodiment, as shown in FIGS. 2 and 4, in each of the plurality of blades 32, the blade trailing edge portion 324 extends in the fan radial direction toward one side in the fan axial direction Da. It is formed so as to be located inside Dr.

Here, the air flow in the inter-blade passages 32a formed between the blades 32 will be described. Then, the vortex WH is generated on the side plate other surface 343 once separated from the side plate 34 . Then, the air flow in the inter-blade passage 32a once separates from the side plate 34 and then advances as indicated by the arrow FL2. That is, the air flow deviates to one side in the fan axial direction Da so as to once separate from the side plate 34 and then reattach to the side plate 34 .

On the other hand, in the centrifugal fan 18 of the present embodiment, as described above, the blade trailing edge portion 324 is formed so as to be located inside the fan radial direction Dr toward one side in the fan axial direction Da. , the amount of work performed by each blade 32 on the side of the main plate 36 is greater than that on the side of the side plate 34 . As a result, the air flow can be drawn again toward the main plate 36 near the outlet of the inter-blade passage 32a as indicated by the arrow FL3. As a result, compared to the case where the trailing edge 324 of the blade is parallel to the fan axis CL, for example, the velocity distribution of the airflow near the outlet of the inter-blade passage 32a is a distribution with no deviation in the fan axis direction Da. , and the noise of the centrifugal fan 18 can be reduced.

In addition, in the centrifugal fan 18, Dsi/Dso, which is the ratio of the inner diameter Dsi of the side plate 34 to the outer diameter Dso of the side plate 34, is "0.5<Dsi/Dso<0.7". Therefore, if the blade trailing edge 324 is parallel to the fan axis CL, the air flow in the inter-blade passage 32a is biased toward the side plate 34 near the exit of the inter-blade passage 32a. The above configuration in which 324 is located inside in the fan radial direction Dr toward one side in the fan axial direction Da can be used. Therefore, the above configuration of the blade trailing edge portion 324 of the present embodiment can be used so as to appropriately reduce the noise of the centrifugal fan 18 .

When Dsi/Dso is, for example, 0.5 or less, the length of the inter-blade passage 32a after the air flow is biased to one side in the fan axial direction Da as indicated by arrow FL2 is sufficiently long. Secured. Therefore, even if the trailing edge 324 of the blade is parallel to the fan axis CL, the air flow will not reach the trailing edge 324 until it reaches the trailing edge 324 after being biased to one side in the direction Da of the fan axis. The deviation of the airflow toward one side in the fan axial direction Da is alleviated. On the other hand, when Dsi/Dso is, for example, 0.7 or more, the airflow in the inter-blade flow passage 32a is shifted to one side in the fan axial direction Da so as to adhere to the side plate 34 again. Edge 324 is reached. In short, the air flows indicated by arrows FL1 and FL2 are interrupted. Therefore, in order to effectively reduce the noise of the centrifugal fan 18 with the configuration in which the blade trailing edge portion 324 is positioned closer to the one side in the fan axial direction Da toward the inner side in the fan radial direction Dr, it is necessary that "0.5< Dsi/Dso<0.7" is required.

The necessity of the relationship "0.5<Dsi/Dso<0.7" has been confirmed, for example, by obtaining analysis results by changing the magnitude of Dsi/Dso in CFD simulations. CFD is an abbreviation for "Computational Fluid Dynamics". In the centrifugal fan of this simulation example, the configuration of the blades 32 is the same as that of the comparative example. That is, in the centrifugal fan of the simulation example, the blade trailing edge 91 (see FIG. 5) is parallel to the fan axis CL, and the thickness tb of the blade 32 at the blade trailing edge 91 is constant. Except for these points, the centrifugal fan of this simulation example is the same as the centrifugal fan 18 of this embodiment.

The analysis results obtained from this CFD simulation are shown in FIGS. 7A to 7D. In this simulation, the rotation speed of the centrifugal fan is assumed to be constant. Note that arrows A1 and A2 in FIGS. 7A to 7D indicate the direction of the air flow in the inter-blade passage 32a. A position P1 indicates a position where the side plate 34 faces the inter-blade passage 32a, and a position P2 indicates a position where the main plate 36 faces the inter-blade passage 32a. In addition, in FIGS. 7A to 7D, the difference in hatching indicates the speed of the airflow (in other words, the flow speed) in the inter-blade passage 32a.

Specifically, FIG. 7A shows the airflow velocity distribution in the inter-blade passage 32a obtained when "Dsi/Dso=0.72". According to FIG. 7A, when "Dsi/Dso=0.72", the velocity distribution of the airflow near the outlet of the inter-blade passage 32a (that is, near the blade trailing edge 91 in FIG. 5) is The high-speed portion is biased toward the other side of the fan axial direction Da (that is, the main plate 36 side).

Further, FIG. 7B shows the velocity distribution of the airflow in the inter-blade passage 32a obtained when "Dsi/Dso=0.68", and FIG. 7C shows the velocity distribution when "Dsi/Dso=0.55". 3 shows the velocity distribution of the airflow in the inter-blade passage 32a obtained in FIG. According to FIGS. 7B and 7C, in the case of "Dsi/Dso=0.68" and in the case of "Dsi/Dso=0.55", the air flow velocity near the exit of the inter-blade passage 32a The distribution is such that the high-speed portion is biased toward one side in the fan axial direction Da (that is, the side plate 34 side).

FIG. 7D shows the air flow velocity distribution in the inter-blade passage 32a obtained when "Dsi/Dso=0.48". According to FIG. 7D, when "Dsi/Dso=0.48", the velocity distribution of the airflow in the vicinity of the outlet of the inter-blade passage 32a has no deviation in the fan axial direction Da.

The following can be said from the airflow velocity distribution shown in FIGS. 7A to 7D. That is, when "0.5<Dsi/Dso<0.7" as shown in FIGS. 7B and 7C, the blade trailing edge 324 is tilted with respect to the fan axial direction Da as in the present embodiment. For example, the velocity distribution of the airflow near the outlet of the inter-blade passage 32a approaches one with no bias in the fan axial direction Da. This is because the blade trailing edge 324 (see FIG. 2) inclined with respect to the fan axis direction Da as in the present embodiment is compared with the blade trailing edge 91 parallel to the fan axis CL. This is because, as described above, the air flow is pulled toward the main plate 36 in the vicinity of the outlet of the inter-blade passage 32a. Therefore, in this case, the inclination of the blade trailing edge 324 with respect to the fan axial direction Da as in the present embodiment leads to noise reduction of the centrifugal fan 18 .

On the other hand, in FIGS. 7A and 7D, the velocity distribution of the airflow near the exit of the inter-blade passage 32a is not one in which the high-speed portion is biased toward the side plate 34 side. Therefore, in the case of "0.7≤Dsi/Dso" and in the case of "Dsi/Dso≤0.5", even if the air flow is drawn toward the main plate 36 near the outlet of the inter-blade passage 32a, , the velocity distribution of the airflow near the outlet does not come close to the one with no deviation in the fan axial direction Da. That is, in this case, even if the blade trailing edge portion 324 is inclined with respect to the fan axial direction Da as in the present embodiment, this does not lead to noise reduction of the centrifugal fan 18 .

As described above, from the analysis results of FIGS. 7A to 7D, the configuration in which the blade trailing edge 324 is inclined with respect to the fan axial direction Da as in the present embodiment is effective in reducing the noise of the centrifugal fan 18. It can be said that the relationship "0.5<Dsi/Dso<0.7" is required to be useful.

Further, when comparing the centrifugal fan 18 of the present embodiment with the centrifugal fan of the comparative example in which the blade trailing edge 91 (see FIG. 5) is parallel to the fan axis CL, as shown in FIG. Low noise of the centrifugal fan 18 is realized in the region. In FIG. 8, the solid line S1 indicates the SPL of this embodiment, and the dashed line S2 indicates the SPL of the comparative example. SPL is an abbreviation for "Sound Pressure Level".

Also, as shown in FIG. 9, in this embodiment, the noise of the centrifugal fan 18 was reduced by 2 dB in overall value as compared with the comparative example. "OA" on the vertical axis of Fig. 9 is an abbreviation for the overall value.

(1) Further, according to the present embodiment, the side plate other surface 343 is located on the other side in the fan axial direction Da toward the outside in the fan radial direction Dr. 2 and 4, the curvature radius of the side plate other surface 343 increases toward the outer side in the fan radial direction Dr. Therefore, while the blade trailing edge portion 324 is located inside the fan radial direction Dr toward one side in the fan axial direction Da, the air is sucked into the centrifugal fan 18 from one side in the fan axial direction Da while obtaining the noise reduction effect. It is possible to guide the trapped air so as to face outward in the fan radial direction Dr.

(2) Further, according to the present embodiment, as shown in FIGS. 2 and 4, in each of the plurality of blades 32, the blade leading edge portion 323 extends from the side plate 34 side to the main plate 36 side. , the main plate 36 side is located inside the fan radial direction Dr. Therefore, since the blades 32 are longer on the side of the main plate 36 than on the side of the side plate 34, the work done by each blade 32 on the side of the main plate 36 can be made larger than that on the side of the side plate 34. This also makes it possible to correct the bias of the airflow in the inter-blade passage 32a to one side in the fan axial direction Da.

(3) Further, according to the present embodiment, the side plate 34 and the main plate 36 each extend outside the blade trailing edge portion 324 in the fan radial direction Dr. Therefore, the trailing edge portion 324 of the blade where the flow velocity of the air flow is maximized can be kept away from the opening end 34c of the case side plate gap 34b. This is advantageous in reducing the noise of the centrifugal fan 18 .

In addition, since the side plate 34 and the main plate 36 each extend to the outer side of the fan radial direction Dr from the blade trailing edge portion 324, the air flow suddenly moves in the fan axial direction Da immediately after coming out of the inter-blade passage 32a. Expansion is suppressed. As a result, the loss caused by the rapid expansion of the airflow can be suppressed, and the centrifugal fan 18 can contribute to noise reduction.

For example, FIG. 10 shows the relationship between Dmo/Db2, which is the ratio of the outer diameter Dmo of the main plate 36 to the other diameter Db2 of the blade trailing edge 324, and the noise reduction effect. That is, the greater the Dmo/Db2, the higher the noise reduction effect. As can be seen from FIG. 10, the extension of the side plate 34 and the main plate 36 to the outer side in the fan radial direction Dr from the blade trailing edge portion 324 acts to enhance the noise reduction effect. 10, the outer diameter Dso of the side plate 34 is the same as the outer diameter Dmo of the main plate 36. As shown in FIG.

(4) Further, according to the present embodiment, the relationship "Db2<Dmo≦1.13×Db2" is established between the diameter Db2 on the other side of the blade trailing edge portion 324 and the outer diameter Dmo of the main plate 36. . Then, according to FIG. 10, when Dmo/Db2 exceeds 1.13, the noise reduction effect gradually increases as Dmo/Db2 increases, but does not change much with respect to Dmo/Db2. Therefore, it is possible to obtain a noise reduction effect while avoiding the size of the centrifugal fan 18 from becoming unnecessarily large.

(5) Further, according to the present embodiment, the first case outer peripheral portion 222 of the first case member 22 is provided so as to overlap the side plate outer peripheral end portion 342 of the centrifugal fan 18 on the outside in the fan radial direction Dr. there is The side plate outer peripheral end portion 342 faces the first case outer peripheral portion 222 in the fan radial direction Dr, and forms an opening end 34c of the case side plate gap 34b between the first case outer peripheral portion 222 and the first case outer peripheral portion 222 .

Therefore, since the opening end 34c of the case-side plate gap 34b is located inside the air outlet 12a of the casing 12 in the fan radial direction Dr, the air pressure at the opening end 34c is lower than the air pressure at the air outlet 12a. . As a result, compared to the case where the opening end 34c is open outside the air outlet 12a, for example, it is possible to suppress the backflow of the blown air flowing into the case side plate gap 34b from the opening end 34c.

(6) According to the present embodiment, as shown in FIGS. 4 to 6, the blade trailing edge portion 324 extends from the side plate 34 side to the main plate 36 side, and the thickness tb of the blade 32 is At the edge portion 324, the side plate 34 side is larger. Therefore, the airflow stall area ST adjacent to the blade trailing edge 324 is larger on the side plate 34 side than on the main plate 36 side. This also acts to prevent the airflow around the trailing edge portion 324 of the blade from deviating to one side in the fan axial direction Da.

(7) Further, according to the present embodiment, as shown in FIGS. 5 and 6, the trailing edge portion of the blade trailing edge portion 324 is The outer surface 324a is curved in a convex shape, and the radius of curvature Rb of the rear edge portion outer surface 324a increases toward the side plate 34 side. Therefore, the pressure surface and the suction surface of the blade 32 can be smoothly connected at the blade trailing edge portion 324 . Therefore, the pressure surface and the suction surface are smoothed at the blade trailing edge 324 while maintaining the tendency that the air flow resistance around the blade trailing edge 324 is larger on the side plate 34 side than on the main plate 36 side. Compared to the case where they are not connected, the overall flow resistance can be lowered.

(Second embodiment)
Next, a second embodiment will be described. In this embodiment, differences from the above-described first embodiment will be mainly described. Also, the same or equivalent parts as those of the above-described embodiment will be omitted or simplified. This also applies to the description of the embodiments that will be described later.

As shown in FIG. 11, in the present embodiment, similarly to the first embodiment, the blade trailing edge portion 324 is formed so as to be positioned more inward in the fan radial direction Dr toward one side in the fan axial direction Da. . However, in this embodiment, the shape of the blade trailing edge portion 324 is different from that in the first embodiment.

Specifically, the blade trailing edge portion 324 of the present embodiment is formed to have a single stepped shape, and is located stepwise toward the inside in the fan radial direction Dr toward one side in the fan axial direction Da.

Except for what has been described above, this embodiment is the same as the first embodiment. In addition, in the present embodiment, it is possible to obtain the same effects as in the first embodiment, which are provided by the configuration common to that of the first embodiment.

(Third Embodiment)
Next, a third embodiment will be described. In this embodiment, differences from the above-described first embodiment will be mainly described.

As shown in FIG. 12, in this embodiment, similarly to the first embodiment, the trailing edge portion 324 of the blade is formed so as to be positioned more inward in the fan radial direction Dr toward one side in the fan axial direction Da. . However, in this embodiment, the shape of the blade trailing edge portion 324 is different from that in the first embodiment.

Specifically, the blade trailing edge portion 324 of this embodiment is formed to have a plurality of stepped shapes, and is located stepwise toward the inside in the fan radial direction Dr toward one side in the fan axial direction Da.

Except for what has been described above, this embodiment is the same as the first embodiment. In addition, in the present embodiment, it is possible to obtain the same effects as in the first embodiment, which are provided by the configuration common to that of the first embodiment.

(Fourth embodiment)
Next, a fourth embodiment will be described. In this embodiment, differences from the above-described first embodiment will be mainly described.

As shown in FIG. 13, in the present embodiment, similarly to the first embodiment, the blade trailing edge portion 324 is formed so as to be positioned more inward in the fan radial direction Dr toward one side in the fan axial direction Da. . However, in this embodiment, the shape of the blade trailing edge portion 324 is different from that in the first embodiment.

Specifically, in the blade trailing edge portion 324 of the present embodiment, a portion on one side in the fan axial direction Da including the portion connected to the side plate 34 of the blade trailing edge portion 324 is parallel to the fan axial center CL. extended. At the other side of the fan axial direction Da, the blade trailing edge portion 324 includes a portion connected to the main plate 36, and the blade trailing edge portion 324 is more inclined toward the fan radial direction Dr. is inclined with respect to the fan axis CL so as to be located outside the .

Except for what has been described above, this embodiment is the same as the first embodiment. In addition, in the present embodiment, it is possible to obtain the same effects as in the first embodiment, which are provided by the configuration common to that of the first embodiment.

(Fifth embodiment)
Next, a fifth embodiment will be described. In this embodiment, differences from the above-described first embodiment will be mainly described.

As shown in FIG. 14, in the present embodiment, similarly to the first embodiment, the blade trailing edge portion 324 is formed so as to be positioned more inward in the fan radial direction Dr toward one side in the fan axial direction Da. . However, in this embodiment, the shape of the blade trailing edge portion 324 is different from that in the first embodiment.

Specifically, the blade trailing edge 324 of this embodiment extends while bending.

Except for what has been described above, this embodiment is the same as the first embodiment. In addition, in the present embodiment, it is possible to obtain the same effects as in the first embodiment, which are provided by the configuration common to that of the first embodiment.

(Sixth embodiment)
Next, a sixth embodiment will be described. In this embodiment, differences from the above-described first embodiment will be mainly described.

As shown in FIG. 15, in this embodiment, as in the first embodiment, the side plate other surface 343 of the centrifugal fan 18 faces the other side of the fan axial direction Da and extends in the fan radial direction Dr. The outer side in the radial direction Dr is positioned on the other side in the fan axial direction Da. However, in this embodiment, the shape of the side plate other surface 343 is different from that in the first embodiment.

Specifically, in the longitudinal section of the blower 10 shown in FIG. 15, the side plate other surface 343 has an inner arc shape 343a and an outer linear shape 343d. This outer linear shape 343d replaces the outer circular arc shape 343b and the outer linear shape 343c (see FIG. 2) in the first embodiment.

In the longitudinal section of FIG. 15, the inner arcuate shape 343a and the outer linear shape 343d of the present embodiment smoothly connect in the order of the inner arcuate shape 343a and the outer linear shape 343d from the inside in the fan radial direction Dr. In addition, the outer linear shape 343d is a linear shape that is inclined with respect to the fan axis CL so that the outer side in the fan radial direction Dr is positioned on the other side in the fan axis direction Da. Thus, in the longitudinal section of FIG. 15, the side plate other surface 343 of this embodiment is formed by one circular arc and one straight line.

Except for what has been described above, this embodiment is the same as the first embodiment. In addition, in the present embodiment, it is possible to obtain the same effects as in the first embodiment, which are provided by the configuration common to that of the first embodiment.

Although this embodiment is a modification based on the first embodiment, it is also possible to combine this embodiment with any of the above-described second to fifth embodiments.

(Seventh embodiment)
Next, a seventh embodiment will be described. In this embodiment, differences from the above-described first embodiment will be mainly described.

As shown in FIG. 16, in this embodiment, as in the first embodiment, the side plate other surface 343 of the centrifugal fan 18 faces the other side of the fan axial direction Da and extends in the fan radial direction Dr. The outer side in the radial direction Dr is positioned on the other side in the fan axial direction Da. However, in this embodiment, the shape of the side plate other surface 343 is different from that in the first embodiment.

Specifically, in the vertical cross section of the fan 10 shown in FIG. 16, the side plate other surface 343 is inclined with respect to the fan axis CL so that the outer side in the fan radial direction Dr is located on the other side in the fan axis direction Da. It is formed in the shape of a straight line. Thus, in the longitudinal section of FIG. 16, the side plate other surface 343 of this embodiment is formed by one straight line.

(1) Therefore, the centrifugal fan 18 can be rotated from one side in the fan axial direction Da while obtaining the noise reduction effect due to the configuration in which the blade trailing edge portion 324 is located on the inner side in the fan radial direction Dr toward one side in the fan axial direction Da. The air sucked inside can be guided outward in the fan radial direction Dr.

Except for what has been described above, this embodiment is the same as the first embodiment. In addition, in the present embodiment, it is possible to obtain the same effects as in the first embodiment, which are provided by the configuration common to that of the first embodiment.

Although this embodiment is a modification based on the first embodiment, it is also possible to combine this embodiment with any of the above-described second to fifth embodiments.

(Eighth embodiment)
Next, an eighth embodiment will be described. In this embodiment, differences from the above-described first embodiment will be mainly described.

As shown in FIG. 17, in this embodiment, as in the first embodiment, the side plate other surface 343 of the centrifugal fan 18 faces the other side of the fan axial direction Da and extends in the fan radial direction Dr. The outer side in the radial direction Dr is positioned on the other side in the fan axial direction Da. However, in this embodiment, the shape of the side plate other surface 343 is different from that in the first embodiment.

Specifically, in the longitudinal section of the fan 10 shown in FIG. 17, the side plate other side surface 343 is formed in a single arc shape extending so as to be located on the other side in the fan axial direction Da toward the outside in the fan radial direction Dr. It is Thus, in the longitudinal section of FIG. 17, the side plate other surface 343 of this embodiment is formed by one circular arc.

Except for what has been described above, this embodiment is the same as the first embodiment. In addition, in the present embodiment, it is possible to obtain the same effects as in the first embodiment, which are provided by the configuration common to that of the first embodiment.

Although this embodiment is a modification based on the first embodiment, it is also possible to combine this embodiment with any of the above-described second to fifth embodiments.

(Ninth embodiment)
Next, a ninth embodiment will be described. In this embodiment, differences from the above-described first embodiment will be mainly described.

As shown in FIG. 18, in this embodiment, as in the first embodiment, the blade leading edge portion 323 extends from the side plate 34 side to the main plate 36 side, and extends inward in the fan radial direction Dr toward the main plate 36 side. formed to be located. However, in this embodiment, the shape of the blade leading edge portion 323 is different from that in the first embodiment.

Specifically, the blade leading edge portion 323 of the present embodiment has a third leading edge portion 323c in addition to the first leading edge portion 323a and the second leading edge portion 323b. These first front edge portion 323a, second front edge portion 323b and third front edge portion 323c are divided into first front edge portion 323a, second front edge portion 323b and third front edge portion 323c from the side plate 34 side. connected in series in order.

The third front edge portion 323 c is connected to the main plate 36 and provided between the second front edge portion 323 b and the main plate 36 . Also, the third front edge portion 323c is formed parallel to the fan axis CL in the longitudinal section of FIG.

Except for what has been described above, this embodiment is the same as the first embodiment. In addition, in the present embodiment, it is possible to obtain the same effects as in the first embodiment, which are provided by the configuration common to that of the first embodiment.

Although this embodiment is a modification based on the first embodiment, it is also possible to combine this embodiment with any of the above-described second to eighth embodiments.

(Tenth embodiment)
Next, a tenth embodiment will be described. In this embodiment, differences from the above-described first embodiment will be mainly described.

As shown in FIG. 19, the electric motor 16 of this embodiment has a motor rotor 40 instead of the motor rotor 161 (see FIG. 2) of the first embodiment. Further, the centrifugal fan 18 of this embodiment has a main plate outer peripheral portion 43 instead of the main plate 36 of the first embodiment, and a rotor connection portion 44 instead of the rotor connection portion 38 of the first embodiment. . In this embodiment, the plurality of blades 32, the side plates 34, the main plate outer peripheral portion 43, and the rotor connecting portion 44 are integrally constructed.

Specifically, an inner peripheral hole 40a corresponding to the inner peripheral hole 36a of the first embodiment is formed in the motor rotor 40 of the present embodiment, and the rotary shaft 14 is fitted into the inner peripheral hole 40a. there is As a result, the motor rotor 40 is directly fixed to the rotating shaft 14 and rotates integrally with the rotating shaft 14 around the fan axis CL.

The motor rotor 40 has a main plate inner peripheral portion 401 and a tubular portion 402 . The main plate inner peripheral portion 401 has a disk-like shape that spreads in the fan radial direction Dr around the fan axis CL. The main plate inner peripheral portion 401 has an inner peripheral main plate surface 401a. The inner peripheral main plate surface 401a is a curved surface that faces one side in the fan axial direction Da and expands in the fan radial direction Dr. formed. The inner peripheral portion 401 of the main plate is a part of the motor rotor 40 , but also a part of the centrifugal fan 18 because it has a function of guiding the air sucked by the centrifugal fan 18 .

Note that FIG. 19 shows a gap between the blade 32 and the main plate inner peripheral portion 401 of the motor rotor 40, but this is for the sake of easy understanding. Each blade 32 may be in contact with the main plate inner peripheral portion 401 or may be spaced apart from the main plate inner peripheral portion 401 as shown.

The cylindrical portion 402 of the motor rotor 40 has a cylindrical shape centered on the fan axis CL, and extends from the radially outer end of the main plate inner peripheral portion 401 toward the other side in the fan axis direction Da. A rotor magnet 162 is fixed inside the tubular portion 402 .

The main plate outer peripheral portion 43 is arranged outside the main plate inner peripheral portion 401 in the fan radial direction Dr, and has a disk-like shape expanding in the fan radial direction Dr around the fan axial center CL. More specifically, the main plate outer peripheral portion 43 continues from the main plate inner peripheral portion 401 and expands outward in the fan radial direction Dr. Therefore, the main plate outer peripheral portion 43 and the main plate inner peripheral portion 401 as a whole correspond to the main plate 36 (see FIG. 2) of the first embodiment.

In addition, the main plate outer peripheral portion 43 has an outer peripheral main plate surface 43a facing one side in the fan axial direction Da. The outer peripheral main plate surface 43a continues from the inner peripheral main plate surface 401a and spreads outward in the fan radial direction Dr. The blade other end portions 322 of the plurality of blades 32 are respectively connected to the outer peripheral main plate surface 43a. The outer peripheral main plate surface 43 a and the inner peripheral main plate surface 401 a as a whole constitute a main plate guide surface 36 b that guides the airflow inside the centrifugal fan 18 .

In addition, the main plate outer peripheral portion 43 has an outer peripheral end portion 431 that is an end portion provided outside in the fan radial direction Dr. This outer peripheral end portion 431 corresponds to the main plate outer peripheral end portion 362 (see FIG. 2) of the first embodiment.

The rotor connecting portion 44 has a cylindrical shape centered on the fan axis CL, and extends from the radially inner end of the main plate outer peripheral portion 43 to the other side in the fan axis direction Da. The cylindrical portion 402 of the motor rotor 40 is fitted inside the rotor connecting portion 44 in the radial direction. Thereby, the rotor connecting portion 44 is fixed to the motor rotor 40 . By fixing the rotor connecting portion 44 to the motor rotor 40 , the centrifugal fan 18 is fixed to the motor rotor 40 and rotates together with the motor rotor 40 .

Except for what has been described above, this embodiment is the same as the first embodiment. In addition, in the present embodiment, the same effects as in the first embodiment can be obtained from the configuration common to that of the first embodiment.

Although this embodiment is a modification based on the first embodiment, it is also possible to combine this embodiment with any of the above-described second to ninth embodiments.

(Other embodiments)
(1) In each of the above-described embodiments, as shown in FIG. 2, the centrifugal fan 18 is a turbo fan, but it may be another type of centrifugal fan such as a radial fan.

(2) In each of the above-described embodiments, as shown in FIG. 2, the electric motor 16 is an outer rotor type brushless DC motor, but the motor type is not limited. For example, the electric motor 16 may be an inner rotor type motor or a motor with brushes.

(3) In each of the embodiments described above, the second front edge portion 323b extends linearly in the vertical cross sections of FIGS. 2 and 4, but it may be curved.

(4) In the first embodiment described above, as shown in FIG. 2, the outer diameter Dmo of the main plate 36 and the outer diameter Dso of the side plate 34 are the same size, but this is an example. For example, the outer diameter Dmo of the main plate 36 may be larger than the outer diameter Dso of the side plate 34 or may be smaller than the outer diameter Dso of the side plate 34 .

(5) It should be noted that the present disclosure is not limited to the above-described embodiments, and can be implemented in various modifications. Moreover, the above-described embodiments are not unrelated to each other, and can be appropriately combined unless the combination is clearly impossible.

Further, in each of the above-described embodiments, it goes without saying that the elements constituting the embodiment are not necessarily essential, unless it is explicitly stated that they are essential, or they are clearly considered essential in principle. stomach. In addition, in each of the above-described embodiments, when numerical values such as the number, numerical value, amount, range, etc. of the constituent elements of the embodiment are mentioned, when it is explicitly stated that they are particularly essential, and when they are clearly limited to a specific number in principle It is not limited to that specific number, except when In addition, in each of the above-described embodiments, when referring to the material, shape, positional relationship, etc. of the constituent elements, unless otherwise specified or in principle limited to a specific material, shape, positional relationship, etc. , its material, shape, positional relationship, and the like.

(Features of the present disclosure)
[First viewpoint]
A centrifugal force that rotates around the fan axis (CL) to suck air from one side in the axial direction (Da) of the fan axis and blow the sucked air outward in the radial direction (Dr) of the fan axis. being a fan
a plurality of blades (32) arranged side by side around the fan axis and having a blade trailing edge (324) on the radially outer side;
a side plate (34) formed with an intake hole (34a) through which air is sucked, provided on the one side of the plurality of blades in the axial direction and connected to each of the plurality of blades;
a main plate (36, 43, 401) connected to each of the plurality of blades on the side opposite to the side plate side and extending in the radial direction;
When the inner diameter of the side plate is Dsi and the outer diameter of the side plate is Dso, Dsi/Dso is 0.5<Dsi/Dso<0.7,
The centrifugal fan, wherein the trailing edge portion of the blade is formed so as to be located radially inward toward the one side in the axial direction.
[Second Viewpoint]
The side plate has a side plate other surface (343) that faces the other side opposite to the one side in the axial direction and spreads in the radial direction,
the other surface of the side plate is located on the other side in the axial direction toward the outer side in the radial direction;
The centrifugal fan according to the first aspect, wherein in a longitudinal section including the fan axis, the radius of curvature of the other surface of the side plate increases toward the outer side in the radial direction.
[Third Viewpoint]
The side plate has a side plate other surface (343) that faces the other side opposite to the one side in the axial direction and spreads in the radial direction,
the other surface of the side plate is located on the other side in the axial direction toward the outer side in the radial direction;
The centrifugal fan according to the first aspect, wherein the other side surface of the side plate is formed by a single arc or straight line in a longitudinal section including the fan axis.
[Fourth point of view]
each of the plurality of blades has a blade leading edge (323) on the inner side in the radial direction;
Any one of the first to third aspects, wherein the leading edge portion of the blade extends from the side plate side to the main plate side and is positioned radially inward toward the main plate side. centrifugal fan described in .
[Fifth Viewpoint]
A centrifugal fan according to a fourth aspect, wherein a portion of the blade leading edge falls within an axial range (Hb1) included in the overall width (Hb) occupied by the blade trailing edge in the axial direction.
[Sixth viewpoint]
The centrifugal fan according to any one of the first to fifth aspects, wherein each of the side plate and the main plate extends outward in the radial direction from the trailing edge of the blade.
[Seventh viewpoint]
each of the side plate and the main plate extends outward in the radial direction from the trailing edge of the blade;
Any one of the first to fifth aspects, wherein a relationship of Db2<Dmo≦1.13×Db2 holds, where Db2 is the maximum outer diameter of the plurality of blades and Dmo is the outer diameter of the main plate. 1. A centrifugal fan according to one.
[Eighth point of view]
A centrifugal fan forming part of a blower (10),
The blower has a side plate adjacent case (22) provided on the side opposite to the blade side with respect to the side plate and arranged away from the side plate,
The side plate has an outer peripheral end portion (342) provided on the outer side in the radial direction, and forms a case side plate gap (34b) between the side plate adjacent case and the side plate,
The side plate adjacent case has a case outer peripheral portion (222) provided so as to overlap the outer peripheral end portion of the side plate in the radial direction,
The first to seventh aspects, wherein the outer peripheral edge of the side plate faces the outer peripheral portion of the case in the radial direction, and an opening end (34c) of the gap between the case side plates is formed between the outer peripheral portion of the case and the outer peripheral portion of the case. A centrifugal fan according to any one of .
[Ninth Aspect]
The blade trailing edge extends from the side plate side to the main plate side,
The centrifugal fan according to any one of the first to eighth aspects, wherein the thickness (tb) of each of the plurality of blades increases toward the side plate at the trailing edge of the blade.
[Tenth Aspect]
In a cross section perpendicular to the fan axis, the blade trailing edge has a convexly curved trailing edge outer surface (324a), and the radius of curvature (Rb) of the trailing edge outer surface increases toward the side plate. A centrifugal fan according to the ninth aspect, which is enlarged.

Claims (10)

1. A centrifugal force that rotates around the fan axis (CL) to suck air from one side in the axial direction (Da) of the fan axis and blow the sucked air outward in the radial direction (Dr) of the fan axis. being a fan
   a plurality of blades (32) arranged side by side around the fan axis and having a blade trailing edge (324) on the radially outer side;
   a side plate (34) formed with an intake hole (34a) through which air is sucked, provided on the one side of the plurality of blades in the axial direction and connected to each of the plurality of blades;
   a main plate (36, 43, 401) connected to each of the plurality of blades on the side opposite to the side plate side and extending in the radial direction;
   When the inner diameter of the side plate is Dsi and the outer diameter of the side plate is Dso, Dsi/Dso is 0.5<Dsi/Dso<0.7,
   The centrifugal fan, wherein the trailing edge portion of the blade is formed so as to be located radially inward toward the one side in the axial direction.
2. The side plate has a side plate other surface (343) that faces the other side opposite to the one side in the axial direction and spreads in the radial direction,
   the other surface of the side plate is located on the other side in the axial direction toward the outer side in the radial direction;
   2. The centrifugal fan according to claim 1, wherein, in a longitudinal section including the fan axis, the radius of curvature of the other surface of the side plate increases toward the outer side in the radial direction.
3. The side plate has a side plate other surface (343) that faces the other side opposite to the one side in the axial direction and spreads in the radial direction,
   the other surface of the side plate is located on the other side in the axial direction toward the outer side in the radial direction;
   2. The centrifugal fan according to claim 1, wherein the other side surface of the side plate is formed by a single arc or straight line in a longitudinal section including the fan axis.
4. each of the plurality of blades has a blade leading edge (323) on the inner side in the radial direction;
   4. The blade leading edge portion according to any one of claims 1 to 3, wherein said blade leading edge portion extends from said side plate side toward said main plate side and is formed so as to be positioned radially inward toward said main plate side. centrifugal fan.
5. The centrifugal fan according to claim 4, wherein a part of said blade leading edge is within an axial range (Hb1) included in the total width (Hb) occupied by said blade trailing edge in said axial direction.
6. The centrifugal fan according to any one of claims 1 to 3, wherein each of said side plate and said main plate extends outward in said radial direction from said blade trailing edge portion.
7. each of the side plate and the main plate extends outward in the radial direction from the trailing edge of the blade;
   4. Any one of claims 1 to 3, wherein a relationship of Db2<Dmo≦1.13×Db2 holds when Db2 is the maximum outer diameter of the plurality of blades and Dmo is the outer diameter of the main plate. centrifugal fan described in .
8. A centrifugal fan forming part of a blower (10),
   The blower has a side plate adjacent case (22) provided on the side opposite to the blade side with respect to the side plate and arranged away from the side plate,
   The side plate has an outer peripheral end portion (342) provided on the outer side in the radial direction, and forms a case side plate gap (34b) between the side plate adjacent case and the side plate,
   The side plate adjacent case has a case outer peripheral portion (222) provided so as to overlap the outer peripheral end portion of the side plate in the radial direction,
   4. The outer peripheral end portion of the side plate is opposed to the outer peripheral portion of the case in the radial direction, and forms an opening end (34c) of the gap between the case side plates and the outer peripheral portion of the case. or a centrifugal fan according to one of the preceding claims.
9. The blade trailing edge extends from the side plate side to the main plate side,
   4. The centrifugal fan according to any one of claims 1 to 3, wherein the thickness (tb) of each of said plurality of blades increases toward said side plate side at said blade trailing edge portion.
10. In a cross section perpendicular to the fan axis, the blade trailing edge has a convexly curved trailing edge outer surface (324a), and the radius of curvature (Rb) of the trailing edge outer surface increases toward the side plate. 10. The centrifugal fan of claim 9, being enlarged.

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