BLOWER

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

The present invention claims priority under 35 U.S.C. § 119 to Japanese Patent Application Nos. 2024-125174 filed on Jul. 31, 2024 and 2025-088126 filed on May 27, 2025, the entire contents of which are incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to a blower.

BACKGROUND

A blower that blows air by rotating a rotor blade body by the driving force of a motor is known. For example, conventionally, a fan that blows air by rotating a rotor positioned in a frame is known. The conventional fan is an axial fan that allows gas to flow in the axial direction of the rotor.

In the blower, noise is generated by wind or the like generated by the rotation of the rotor blade body. Therefore, conventionally, it is known that such noise is reduced by a sound absorbing material. The conventional fan includes a rotor having a plurality of blades, a frame accommodating the rotor, and an inner lining layer formed of a sound absorbing material on an inner surface of the frame. Conventionally, examples of the sound absorbing material include felt and nonwoven fabric. As a result, the conventional fan obtains a sound absorbing effect.

Conventionally, as described above, examples of the sound absorbing material include felt and nonwoven fabric. The material such as the felt or the nonwoven fabric has, for example, fiber materials and voids formed between the fiber materials.

In the material, a solid propagation wave propagates to the fiber material or an air propagation wave propagates in the void according to an incident sound wave. In addition, it is considered that sound energy is converted into thermal energy in the material by interaction of a solid propagation wave or an air propagation wave. By such an action, it is considered that a sound absorbing effect can be obtained in the material.

For this reason, in the conventional material of the sound absorbing material, a loss of a flow velocity or momentum of the gas flowing through the surface of the material occurs due to permeation of the gas into the material.

Therefore, there is a demand for a blower capable of reducing the noise generated by rotation of the rotor blade body while preventing a loss of the flow velocity or momentum of the gas.

SUMMARY

A blower according to an exemplary embodiment of the present invention includes a rotor blade body rotatable about a central axis extending in an axial direction, a motor that rotates the rotor blade body, a housing including a ventilation passage and surrounding the rotor blade body and the motor, and a noise reducing member located in the ventilation passage. The noise reducing member is a porous member having a plurality of bubbles opened to the ventilation passage on the surface side of the noise reducing member.

The above and other elements, features, steps, characteristics and advantages of the present disclosure will become more apparent from the following detailed description of the preferred embodiments with reference to the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front side perspective view illustrating a schematic configuration of a blower according to an embodiment;

FIG. 2 is a rear side perspective view illustrating a schematic configuration of a blower according to a first modification;

FIG. 3 is a cross-sectional view taken along line III-III of FIG. 2;

FIG. 4 is a partially enlarged cross-sectional view illustrating a schematic configuration of a blower according to a second modification;

FIG. 5 is an enlarged cross-sectional view illustrating a schematic configuration of a blower according to a third modification;

FIG. 6 is an enlarged cross-sectional view illustrating a schematic configuration of a blower according to a fourth modification;

FIG. 7 is a cross-sectional view illustrating a schematic configuration of a moving blade according to an example embodiment; and

FIG. 8 is a cross-sectional view illustrating a schematic configuration of a moving blade according to a comparative example without a noise reducing member.

DETAILED DESCRIPTION

Hereinafter, an exemplary embodiment of the present invention will be described in detail with reference to the drawings. The same or corresponding parts in the drawings are denoted by the same reference numerals, and the description thereof will not be repeated. In addition, the dimensions of the components in the drawings do not faithfully represent the actual dimensions of the components, the dimensional ratios of the components, and the like.

Note that in the following description, in blowers 10, 11, 12, 13, 14, and 15, a direction parallel to a central axis X1 of a moving blade 20 is referred to as an axial direction, a direction perpendicular to the central axis X1 is referred to as a radial direction, and a direction along an arc centered on the central axis X1 is referred to as a circumferential direction.

In addition, in the following description, “same” includes not only a case of being strictly the same but also a range that can be regarded as being substantially the same.

The following description also shows that the expression, “fix”, “connect”, “attach”, or the like, is used not only when members are directly fixed to each other, but also when members are fixed to each other with another member interposed therebetween, for example. That is, in the following description, the expression such as fixing includes the meaning of direct and indirect fixing between members.

FIG. 1 is a front side perspective view illustrating a schematic configuration of a blower 10 according to an embodiment. Referring to FIG. 1, the blower 10 is an axial fan that sucks in gas from the other side in the axial direction and sends out the sucked gas to one side in the axial direction. The blower 10 includes a moving blade 20 as a rotor blade body, a motor 30, a housing 40, and a noise reducing member 50.

The moving blade 20 is a rotor blade body that is rotatable about the central axis X1 extending in the axial direction as the motor 30 rotates. The moving blade 20 includes a plurality of blades extending outward in the radial direction of the central axis X1.

The motor 30 rotates the moving blade 20 by rotating the shaft about the central axis X1. As the motor 30, a known motor having a rotor and a stator can be adopted.

The housing 40 has a ventilation passage AP1 and surrounds the radial outside of the moving blade 20 and the motor 30. The housing 40 has a cylindrical portion 41 extending along the axial direction. The cylindrical portion 41 has an intake port 411 located on the other side in the axial direction and an exhaust port 412 located on one side in the axial direction. The ventilation passage AP1 is connected to the intake port 411 and the exhaust port 412. When the moving blade 20 rotates, gas is sucked from the intake port 411, and the sucked gas is sent out from the exhaust port 412 via the ventilation passage AP1.

The noise reducing member 50 is a member that reduces noise generated by the rotation of the moving blade 20. The noise reducing member 50 is located in the ventilation passage AP1. Specifically, the noise reducing member 50 is located on at least a part of the inner surface of the cylindrical portion 41, and is located to face at least a part of the moving blade 20 in the radial direction of the central axis X1.

The noise reducing member 50 is a synthetic resin member having a plurality of air bubbles 51 opened to the ventilation passage AP1 on a surface 501 side of the noise reducing member 50. The noise reducing member 50 includes a plurality of air bubbles 52 in the noise reducing member 50. That is, the noise reducing member 50 is a porous member having the plurality of air bubbles 51 and 52. Examples of the synthetic resin member include foamed resin members such as polystyrene, polyolefin, polyester, polyurethane, ethylene-vinyl acetate copolymer resin (EVA), and polyvinyl alcohol (PVA).

The plurality of air bubbles 51 and 52 are closed cells spaced apart from each other. The noise reducing member 50 having such a plurality of air bubbles 51 and 52 can be easily formed, for example, by putting a foaming agent into a synthetic resin material and foaming the foaming agent in the synthetic resin material by heating or the like.

As described above, the blower 10 includes the moving blade 20 as a rotor blade body rotatable about the central axis X1 extending in the axial direction, the motor 30 that rotates the moving blade 20, the housing 40 that includes the ventilation passage AP1 and surrounds the moving blade 20 and the motor 30, and the noise reducing member 50 located in the ventilation passage AP1. The noise reducing member 50 is a porous member having the plurality of air bubbles 51 opened to the ventilation passage AP1 on the surface 501 side of the noise reducing member 50.

According to the above configuration, when the gas passes through the inside of the ventilation passage AP1 by the rotation of the moving blade 20 as a rotor blade body, it is possible to reduce the flow velocity fluctuation of a part AF1 of the gas passing over the surface 501 of the noise reducing member 50 having the air bubbles 51. The part AF1 of the gas is, for example, a gas flowing through a boundary layer affected by frictional resistance against the surface 501 of the noise reducing member 50 due to the viscosity of the gas. As a result, it is possible to reduce the flow velocity fluctuation of the gas passing over the surface 501 of the noise reducing member 50. Therefore, the noise generated by the flow velocity fluctuation can be reduced.

In addition, according to the noise reducing member 50 that is a porous member having the plurality of air bubbles 51, it is possible to prevent a loss of the flow velocity or the momentum of the gas as compared with a material such as a nonwoven fabric. As a result, it is possible to reduce the noise generated by the rotation of the moving blade 20 by reducing the flow velocity fluctuation due to the frictional resistance of the gas flowing in the ventilation passage AP1 while preventing the loss of the flow velocity or momentum of the gas.

Furthermore, the noise reducing member 50 is a porous member in which a flow of gas in the thickness direction of the noise reducing member 50 does not permeate. That is, the noise reducing member 50 is a porous member in which a flow of gas in the intersecting direction of the surface 501 of the noise reducing member 50 and the plurality of air bubbles 51 does not permeate. That is, while the gas moves in the air bubbles 51 in the porous member, the gas does not substantially pass through the resin portion. Since the noise reducing member 50 is an air-impermeable porous member in which a flow of gas does not permeate, the gas flowing in the direction intersecting the surface of the porous member does not enter the noise reducing member 50 that is a porous member.

Specifically, as illustrated in a partially enlarged sectional view XS1 of the blower 10 in FIG. 1, a gas flow AF11 moving in the intersecting direction with respect to the surface 501 of the noise reducing member 50 changes its direction at the surface 501 of the noise reducing member 50. Several patterns are conceivable for the movement of the gas flow AF11. For example, the gas flow AF11 may bounce off the surface 501 of the noise reducing member 50 in a direction away from the surface 501 of the noise reducing member 50. For example, it is conceivable that the gas flow AF11 changes its direction in a direction along the surface 501 of the noise reducing member 50 on the surface 501 of the noise reducing member 50.

The gas flow AF12 flowing into the plurality of air bubbles 51 changes its direction on the surfaces of the plurality of air bubbles 51. Several patterns are conceivable for the movement of the gas flow AF12 flowing into the air bubble 51. For example, it is conceivable that the gas flow AF12 enters the air bubble 51 in the thickness direction and then flows along the surface of the air bubble 51 to flow out to the outside. In addition, it is conceivable that the gas flow AF12 enters the air bubble 51 in an oblique direction intersecting the thickness direction for example, and then flows along the surface of the air bubble 51 to flow out to the outside. Furthermore, it is conceivable that the gas flow AF12 enters the air bubble 51 in an oblique direction intersecting the thickness direction for example, and then bounces back in a direction away from the surface of the air bubble 51 on the surface of the air bubble 51.

Therefore, the gas flow AF11 moving in the intersecting direction with respect to the surface 501 of the noise reducing member 50 or the gas flow AF12 flowing into the plurality of air bubbles 51 does not enter the plurality of air bubbles 52 located in the noise reducing member 50.

As a result, it is possible to suppress the flow rate of the gas passing over the surface 501 of the noise reducing member 50 from permeating into the noise reducing member 50 and decreasing, and thus, it is possible to prevent the flow velocity or the momentum of the gas from decreasing.

In addition, the plurality of air bubbles 51 and 52 are closed cells spaced apart from each other. Therefore, a wall that blocks the movement of the gas is located between the air bubbles. In other words, the air bubbles are not connected to each other. Therefore, in the noise reducing member 50, since the gas does not pass from an air bubble to another air bubble, it is possible to further suppress a decrease in the flow velocity of the gas passing through the ventilation passage AP1.

In the configuration described above, the noise reducing member 50 faces at least a part of the moving blade 20 in the radial direction. As described above, according to the configuration in which the noise reducing member 50 is located radially outside the moving blade 20, the noise generated by the gas passing through the ventilation passage AP1 located between the moving blade 20 and the noise reducing member 50 can be further reduced.

FIG. 2 is a rear side perspective view illustrating a schematic configuration of a blower 11 according to a first modification. FIG. 3 is a cross-sectional view taken along line III-III of FIG. 2. The blower 11 according to the first modification of the present embodiment is different from the blower 10 according to the first embodiment in further including a stator vane 422. Hereinafter, description of the same configurations as those of the above embodiment will be omitted, and only configurations different from those of the above embodiment will be described.

With reference to FIGS. 2 and 3, the blower 11 includes the moving blade 20, the motor 30, the housing 40, and noise reducing members 50 and 60.

The housing 40 includes a cylindrical portion 41 and a support portion 42. The support portion 42 is located on one side in the axial direction of the moving blade 20. The support portion 42 supports the moving blade 20 and the motor 30 with respect to the cylindrical portion 41. The support portion 42 includes a holding portion 421 and a plurality of stator vanes 422.

The holding portion 421 is located on one side in the axial direction with respect to the moving blade 20. The holding portion 421 is located at the center in the radial direction and holds the motor 30.

The plurality of stator vanes 422 extend radially outward from the radially outer end of the holding portion 421 and are connected to the inner surface of the cylindrical portion 41. The plurality of stator vanes 422 have a function of adjusting the airflow flowing through the ventilation passage AP1 when the moving blade 20 rotates. The plurality of stator vanes 422 also function as ribs that connect the cylindrical portion 41 and the holding portion 421. Note that a lead wire for supplying electric power to the motor 30 may be wired to at least one of the plurality of stator vanes 422.

The noise reducing member 50 is located at a position radially facing at least a part of the moving blade 20 and at the other side in the axial direction with respect to support portion 42.

Like the noise reducing member 50, the noise reducing member 60 is a porous synthetic resin member having a plurality of air bubbles 51 and 52. A part of the noise reducing member 60 is located on the inner surface of the cylindrical portion 41 located on one side in the axial direction with respect to the moving blade 20. Another part of the noise reducing member 60 is located at a position radially facing at least a part of the moving blade 20.

According to the above configuration, the noise reducing member 60 can reduce the noise generated when the gas escapes between the support portion 42 while arranging the airflow by the plurality of stator vanes 422.

FIG. 4 is a partially enlarged cross-sectional view illustrating a schematic configuration of a blower 12 according to a second modification. The blower 12 according to the second modification is different from the blower 10 according to above embodiment in that the blower 12 of the second modification includes a noise reducing member 70 having an open-cell structure, whereas the blower 10 of the above embodiment includes the noise reducing member 50 having a closed-cell structure. Hereinafter, description of the same configurations as those of the above embodiment will be omitted, and only configurations different from those of the above embodiment will be described.

Referring to FIG. 4, the blower 12 includes a noise reducing member 70 having an open-cell structure. The noise reducing member 70 includes a plurality of air bubbles 71, 72, and 73 that form an open cell. The noise reducing member 70 may include a plurality of air bubbles 51 and 52 as closed cells. In the plurality of air bubbles, the air bubbles may be in contact with each other.

For example, a portion of the air bubble 71 is connected to the air bubble 72. A portion of the air bubble 72 is connected to the air bubble 73. The air bubble 71 is open to the ventilation passage AP1. The air bubble 72 is located radially outward of the air bubble 71. The air bubble 73 is located further radially outward of the air bubble 72. For example, while the gas moves in the air bubbles 71, 72, and 73 in the porous member, the gas does not substantially pass through the resin portion.

An open cell 701 formed of a plurality of continuous air bubbles may penetrate from a front surface 501 located on one surface in the thickness direction of the noise reducing member 70 to a rear surface 502 located on the other surface in the thickness direction of the noise reducing member 70. The radial dimension of an open cell 702 formed of a plurality of continuous air bubbles may be smaller than a thickness TK1 of the noise reducing member 70. Therefore, even if the airflow enters the open cell 702, the airflow does not reach the rear surface 502 of the noise reducing member 70.

A part of the gas passing over the surface 501 of the noise reducing member 70 during blowing enters the open cells 701 and 702.

The inner surface of the cylindrical portion 41 of the housing 40 is in contact with the rear surface 502 of the noise reducing member 70. Accordingly, a gas flow AF13 entering the open cell 701 penetrating the noise reducing member 70 in the thickness direction changes its direction on the inner surface of the cylindrical portion 41. The thickness TK1 of the noise reducing member 70 is a dimension in which a loss of momentum or the like due to gas entering the open cells 701 and 702 does not substantially occur.

In the above-described configuration, the plurality of air bubbles 71, 72, and 73 are formed of the open cell 701 in which a cell and another cell are connected at least partially. When the rear surface 502 or a side surface other than the front surface 501 of the noise reducing member 70, which is a porous member, is covered with an air-impermeable member that does not transmit the gas, similarly to the closed cells described above, the gas can be prevented from permeating the noise reducing member 70.

In the above configuration, the rear surface 502 of the noise reducing member 70 is covered with the cylindrical portion 41 that is an air-impermeable member. Therefore, the gas can be prevented from permeating the noise reducing member 70. As a result, since the gas does not permeate the noise reducing member 70, a decrease in the flow rate can be suppressed.

FIG. 5 is an enlarged cross-sectional view illustrating a schematic configuration of a blower 13 according to a third modification. The blower 13 according to the third modification is different from the blower 11 according to the first modification in that the housing 40 further includes an inclined portion 45. Hereinafter, description of the same configurations as those of the first modification will be omitted, and only configurations different from those of the first modification will be described.

With reference to FIG. 5, the blower 13 includes the moving blade 20, the motor 30, the housing 40, and the noise reducing members 50 and 60. The housing 40 includes the cylindrical portion 41, the support portion 42, and the inclined portion 45.

The inclined portion 45 is connected to the other axial end of the cylindrical portion 41. The inclined portion 45 is inclined radially outward from one side to the other side in the axial direction. The inclination of the inclined portion 45 may be linear or curved when a cross section orthogonal to the radial direction is viewed. The intake port 451 is located at the other axial end of the inclined portion 45. From another point of view, the opening dimension of the intake port 451 is larger than the inner diameter dimension of the cylindrical portion 41. That is, the inner diameter of the inclined portion 45 is larger than the inner diameter of the cylindrical portion 41.

The noise reducing members 50 and 60 are located on at least a part of the inner surface of the cylindrical portion 41. That is, the noise reducing members 50 and 60 are not disposed on the inclined portion 45.

In the above-described configuration, the noise reducing members 50 and 60 are located on the inner surface of the cylindrical portion 41, which is narrower than the intake port 451 located at the other axial end of the inclined portion 45, in the ventilation passage AP1. The noise reducing members 50 and 60 are located at positions where a flow of gas is likely to be hindered and noise is likely to be generated because of their narrow width. Since the noise reducing members 50 and 60 are located at positions where such noise is likely to be generated, the effects of suppressing the decrease in the flow velocity of the gas and reducing the noise can be further enhanced.

FIG. 6 is an enlarged cross-sectional view illustrating a schematic configuration of a blower 14 according to a fourth modification. The blower 14 according to the fourth modification is different from the blower 11 according to the first modification in that the noise reducing member 50 is located on the other axial side of the moving blade 20 in the blower 14 of the fourth modification, whereas the noise reducing member 50 is located to radially face at least a part of the moving blade 20 in the blower 11 of the first modification. Hereinafter, description of the same configurations as those of the first modification will be omitted, and only configurations different from those of the first modification will be described.

With reference to FIG. 6, the blower 14 includes the moving blade 20, the motor 30, the housing 40, and the noise reducing members 50 and 60. The housing 40 includes a cylindrical portion 410 and the support portion 42.

The axial length D410 of the cylindrical portion 410 is longer than the axial length D41 of the cylindrical portion 41 of the blower 11 according to the first modification illustrated in FIG. 3.

The noise reducing member 50 is disposed on a part of the inner surface of the housing 40, and is located on the other side in the axial direction with respect to the moving blade 20. Specifically, the noise reducing member 50 is located on a part of the inner surface of the cylindrical portion 410 of the housing 40 located on the other side in the axial direction of the moving blade 20. Therefore, the noise reducing member 50 is located on the other side in the axial direction with respect to the other axial end portion 21 of the moving blade 20.

According to the above configuration, the noise generated by the gas flowing to the other position in the axial direction than the other axial end portion 21 of the moving blade 20 can be reduced, and a decrease in the flow velocity of the gas can be suppressed.

FIG. 7 is a cross-sectional view illustrating a schematic configuration of a moving blade 210 according to an example embodiment. FIG. 8 is a cross-sectional view illustrating a schematic configuration of a moving blade 200 according to a comparative example without a noise reducing member. The moving blade 210 according to the example embodiment and the moving blade 200 according to the comparative example are simulation models on a computer. In the moving blade 210, noise reducing members 710 and 720 each having an open cell structure similar to the noise reducing member 70 in the blower 12 according to the second modification are disposed. Hereinafter, description of the same configurations as those of the second modification will be omitted, and only configurations different from those of the second modification will be described.

Referring to FIG. 7, in the moving blade 210 according to the example embodiment, the noise reducing members 710 and 720 having the open-cell structure are located on the surfaces of the moving blade 210. A surface of each of the noise reducing members 710 and 720 is positioned flat without a step with respect to the surface of moving blade 210. The noise reducing member 710 is located on one side in the blade thickness direction of the moving blade 210. The noise reducing member 720 is located on the other side in the blade thickness direction of the moving blade 210.

Note that a cross section of the airfoil of the moving blade 210 described below is a cross section in a direction in which gas flows. Hereinafter, a direction in which a chord CH1 connecting a leading edge 211 and a trailing edge 212 of the airfoil of the moving blade 210 extends is referred to as a chord length direction CL1. In addition, the upstream in the gas flow is referred to as the front in the chord length direction CL1, and the downstream in the gas flow is referred to as the rear in the chord length direction CL1. A direction orthogonal to the chord length direction CL1 is referred to as a blade thickness direction TK1. The leading edge 211 is located at the front end of the airfoil of the moving blade 210 in the chord length direction CL1. The trailing edge 212 is located at the trailing end of the airfoil of the moving blade 210 in the chord length direction CL1.

The moving blade 210 has a curved surface 213 that is convex toward one side in the blade thickness direction with respect to the chord CH1. The noise reducing member 710 is located on at least a part of the curved surface 213. The curved surface 213 has a maximum blade thickness portion 2131 located at a position where the blade thickness in the blade thickness direction TK1 of the airfoil is maximum.

The noise reducing member 710 includes an inlet portion 711, an outlet portion 712, a rear inlet portion 713, and a rear outlet portion 714.

The inlet portion 711 is located upstream of the maximum blade thickness portion 2131 in the chord length direction CL1. The inlet portion 711 is a portion into which gas flows when the gas flows from the front to the rear in the chord length direction CL1 with respect to the moving blade 210.

The outlet portion 712 is located downstream of the inlet portion 711 in the chord length direction CL1. The outlet portion 712 is a portion through which the gas flowing into the inlet portion 711 flows out.

The rear inlet portion 713 is located behind the outlet portion 712 and the rear outlet portion 714 to be described later in the chord length direction CL1. The rear inlet portion 713 is a portion into which the gas flowing to the rear side of the maximum blade thickness portion 2131 flows.

The rear outlet portion 714 is located between the outlet portion 712 and the rear inlet portion 713 in the chord length direction CL1. The rear outlet portion 714 is a portion from which the gas flowing into the rear inlet portion 713 flows out.

For comparison, a simulation result when an airflow is generated will be described below with reference to FIG. 8. When an airflow is generated, in the moving blade 200 according to the comparative example that does not include a noise reducing member, a main flow MAF1 flows from the front to the rear of the moving blade 200. In the moving blade 200, entrainment MAF11 of the main flow MAF1 is generated behind the moving blade 200. As a result, a vortex is generated by the entrainment MAF11. Therefore, noise due to generation of a vortex is generated.

On the other hand, in the moving blade 210 according to the example embodiment, the flow of gas is as described below. When the airflow impinges on the leading edge 211 of the moving blade 210, the pressure on the blade surface around the leading edge 211 and the inlet portion 711 increases. As a result, a part of the airflow moves in the vicinity of the surface of the moving blade 210 as the main flow MAF1, while the rest of the airflow flows into the noise reducing member 710 from the inlet portion 711.

The outlet portion 712 is located behind the maximum blade thickness portion 2131, for example. On the surface of the outlet portion 712, the flow velocity of the gas is larger than that at other positions, and the pressure is smaller than that at other positions. The pressure on the surface of the outlet portion 712 is, for example, a negative pressure.

In addition, in the rear inlet portion 713 located behind the outlet portion 712, the flow velocity of the gas decreases, while the pressure on the blade surface increases. Therefore, the gas flows into the noise reducing member 710 from the rear inlet portion 713.

As described above, since the pressure on the surface of outlet portion 712 is, for example, a negative pressure, the gas flowing in from the inlet portion 711 of the noise reducing member 710 passes rearward in the noise reducing member 710 and flows out from the outlet portion 712. The gas flowing in from the rear inlet portion 713 passes forward in the noise reducing member 710 and flows out from the rear outlet portion 714.

In the configuration of the moving blade 210, the flow of the main flow MAF1 is regulated by the gas flowing out from the outlet portion 712 and the rear outlet portion 714, so that occurrence of entrainment of the main flow MAF1 can be suppressed. Therefore, since generation of a vortex due to entrainment can be suppressed, the generation of noise can be suppressed.

As described above, the above-described effects can also be expected in a blower 15 including the moving blade 210. That is, the blower 15 includes the moving blade 210 as a rotor blade body, the motor 30, the housing 40, and the noise reducing member 710. The moving blade 210 includes the curved surface 213 that is convex toward one side in the blade thickness direction with respect to the chord CH1 connecting the leading edge 211 and the trailing edge 212 in the airfoil of the moving blade 210. The noise reducing member 710 is located on at least a part of the curved surface 213.

According to the above configuration, since generation of a vortex due to entrainment of the main flow MAF1 can be suppressed, generation of the noise can be suppressed.

The curved surface 213 also includes the maximum blade thickness portion 2131 located at a position where the blade thickness of the airfoil is maximum. The noise reducing member 710 includes the inlet portion 711, and the outlet portion 712.

According to the above configuration, the flow of the main flow MAF1 can be regulated by the gas flowing in from the inlet portion 711 and then flowing out from the outlet portion 712.

While the embodiment of the present invention has been described above, the above embodiment is merely an example for implementing the present invention. Thus, the above-described embodiment can be appropriately modified and implemented within a range without departing from the gist thereof and being limited to the above-described embodiment.

In the embodiment and the first to fourth modifications (hereinafter referred to as “embodiment and the like”), the noise reducing members 50, 60, and 70 are foamed resin members. However, the noise reducing member may be a member other than resin. For example, the noise reducing member may be a metal member.

In the above embodiment and the like, the noise reducing members 50, 60, and 70 are located on a part of the inner surface of the housing 40 in the axial direction. However, the noise reducing member may be located at a part of the inner surface of the housing in the circumferential direction, or may be located on the entire circumference in the circumferential direction. The noise reducing member may be located on at least a part of the surface of the moving blade that is a rotor blade body. The noise reducing member can be located at any position in the ventilation passage.

In the first, third, and fourth modifications, the blowers 11, 13, and 14 include the noise reducing members 50 and 60. However, the noise reducing members may not include a noise reducing member located on a part of the inner surface of the cylindrical portion located on one side in the axial direction with respect to the moving blade, and the noise reducing members may not include a noise reducing member located radially outside the moving blade or located on the other side in the axial direction of the moving blade.

Although not specifically described in the first, third, and fourth modifications, the noise reducing member may be located on at least a part of the surface of the stator vane.

In the above embodiment and the like, each of the blowers 10, 11, 12, 13, and 14 is an axial fan having the moving blade 20 as a rotor blade body. However, the blower may be a blower other than the axial fan. The blower may be, for example, a centrifugal fan that takes in air in the axial direction and exhausts air in a centrifugal direction orthogonal to the axial direction. The blower may be a mixed flow fan that sucks air in the axial direction and discharges air obliquely. The blower may have a plurality of moving blades. In the blower, a plurality of moving blades may be positioned side by side in the axial direction.

In the above embodiment and the like, the moving blade 20 is located in the housing 40. However, at least a part of the moving blade may protrude outward from the other axial end of the housing.

In the first, third, and fourth modifications, the blowers 11, 13, and 14 include the stator vane 422. However, the blower may not include the stator vane. For example, in the blower, a rib may support the holding portion with respect to the cylindrical portion instead of the stator vane described above.

In the first, third, and fourth modifications, the support portion 42 is located in the cylindrical portion 41. However, at least a part of the support portion may protrude outward from one axial end of the cylindrical portion. For example, the stator vane may support the holding portion at a position protruding outward from one axial end of the cylindrical portion.

In the third modification, the noise reducing members 50 and 60 are located on at least a part of the inner surface of the cylindrical portion 41 and are not located on the inclined portion 45. However, the noise reducing member may be located on the inclined portion.

In the fourth modification, the noise reducing member 50 is located on the other side in the axial direction with respect to the moving blade 20. However, the noise reducing member may be located at a position radially facing at least a part of the moving blade.

In the above example embodiment, the noise reducing member 720 is located on the other surface in the blade thickness direction of the moving blade 210. However, the noise reducing member may not be located on the other surface in the blade thickness direction of the moving blade.

Although not specifically described in the above example embodiment, the airfoil of the moving blade may be a symmetrical blade or an airfoil other than a symmetrical blade. The airfoil of the moving blade may have a camber that is the difference between the chord and the centerline of the airfoil.

In the above example embodiment, the noise reducing members 710 and 720 each have an open cell structure. However, the noise reducing member may have a closed cell structure.

The present technique can also have configurations as described below.

• • (1) A blower includes a rotor blade body rotatable about a central axis extending in an axial direction, a motor that rotates the rotor blade body, a housing including a ventilation passage and surrounding the rotor blade body and the motor, and a noise reducing member located in the ventilation passage. The noise reducing member is an impermeable porous member which includes a plurality of air bubbles opened to the ventilation passage on the surface side of the noise reducing member and in which a flow of gas in the intersecting direction of the surface of the noise reducing member and the plurality of air bubbles does not permeate.
  • (2) The blower according to (1), wherein the plurality of air bubbles are spaced apart from each other.
  • (3) The blower according to (1), wherein among the plurality of air bubbles, an air bubble is connected to another air bubble at least in part.
  • (4) The blower according to any one of (1) to (3), wherein the noise reducing member is located on at least a part of an inner surface of the housing, and is located to face at least a part of the rotor blade body in a radial direction of the central axis.
  • (5) The blower according to any one of (1) to (4), wherein the housing further includes: a cylindrical portion extending along the axial direction; and an inclined portion inclined outward in the radial direction from one end in the axial direction to the other side in the axial direction, and the noise reducing member is located on an inner surface of the cylindrical portion.
  • (6) The blower according to any one of (1) to (4), wherein the housing includes: a cylindrical portion extending along the axial direction; and a support portion that is located on one side in the axial direction of the rotor blade body and supports the rotor blade body and the motor with respect to the cylindrical portion, and the noise reducing member is located on at least either a part of an inner surface of the cylindrical portion located on one side in the axial direction with respect to the rotor blade body or a surface of the support portion.
  • (7) The blower according to (6), wherein the support portion includes a stator vane.
  • (8) The blower according to any one of (1) to (7), wherein the noise reducing member is disposed on an inner surface of the housing and is located on the other side in the axial direction with respect to the rotor blade body.
  • (9) The blower according to any one of (1) to (8), wherein the noise reducing member is a porous member in which a flow of gas in a thickness direction does not permeate.
  • (10) The blower according to (2) or (3), wherein the noise reducing member is a synthetic resin member.
  • (11) The blower according to any one of (1) to (10), wherein an airfoil of the rotor blade body includes a curved surface that is convex toward one side in a blade thickness direction with respect to a chord connecting a leading edge and a trailing edge in the airfoil, and the noise reducing member is located on at least a part of the curved surface.
  • (12) The blower according to (11), wherein the curved surface includes a maximum blade thickness portion located at a position at which a blade thickness of the airfoil is maximum, and the noise reducing member includes, in a chord length direction in which the chord extends: an inlet portion located upstream of the maximum blade thickness portion and into which gas flows; and an outlet portion located downstream of the inlet portion and through which the gas flowing into the inlet portion flows out.

The present invention is applicable to, for example, a blower that rotates the moving blade by the driving force of a motor.

Features of the above-described preferred embodiments and the modifications thereof may be combined appropriately as long as no conflict arises.

While preferred embodiments of the present disclosure have been described above, it is to be understood that variations and modifications will be apparent to those skilled in the art without departing from the scope and spirit of the present disclosure. The scope of the present disclosure, therefore, is to be determined solely by the following claims.