Blower

Abstract

A blower is provided with: a motor unit having a rotor that rotates about a central axis; an impeller portion that is rotatable together with the rotor; a housing that accommodates the impeller part therein; and a reflecting plate that is disposed between the impeller part and the inner surface of the housing in the radial direction and that extends in the circumferential direction. A part of the inner side surface faces the impeller part in the radial direction, and another part of the inner side surface faces the reflecting plate in the radial direction.

Description

Technical Field

[0001] This invention relates to blowers. Background Technology

[0002] A centrifugal fan is known, comprising: an impeller with a plurality of blades arranged radially relative to a rotation axis; and a fan housing having a peripheral wall plate surrounding the outer periphery of the impeller (e.g., Patent Document 1).

[0003] Patent Document 1: Japanese Patent No. 5952801

[0004] In the centrifugal fan described above, sound waves are generated as the impeller rotates around its axis and the air is conveyed by the blades. If these sound waves resonate with each other on the inner surfaces of the peripheral wall, the noise level of the centrifugal fan during operation may increase. Summary of the Invention

[0005] In view of the above circumstances, one of the objectives of this invention is to provide a blower capable of suppressing noise.

[0006] One embodiment of the blower of the present invention comprises: a motor section having a rotor that rotates about a central axis; an impeller section capable of rotating together with the rotor; a housing that internally accommodates the impeller section; and a reflector plate that is radially disposed between the impeller section and the inner side surface of the housing and extends circumferentially. A portion of the inner side surface is radially opposed to the impeller section, and another portion of the inner side surface is radially opposed to the reflector plate.

[0007] According to one aspect of the present invention, noise can be suppressed in a blower. Attached Figure Description

[0008] Figure 1 This is a perspective view showing the blower of the first embodiment.

[0009] Figure 2 This is a cross-sectional view showing the blower of the first embodiment.

[0010] Figure 3 This is a cross-sectional view showing the blower of the first embodiment, and is Figure 2 Sectional view III-III.

[0011] Figure 4 This is a cross-sectional view showing the blower of the second embodiment.

[0012] Figure 5 This is a cross-sectional view showing the blower of the second embodiment, and is... Figure 4 VV sectional view.

[0013] Figure 6 This is a cross-sectional view showing the blower of the third embodiment.

[0014] Figure 7 This is a cross-sectional view showing the blower of the third embodiment, and is Figure 6 Sectional view VII-VII.

[0015] Figure 8 This is a side view obtained by observing the reflector of the third embodiment from the radial inside.

[0016] Figure 9 The first figure shows the noise reduction of the blower according to the third embodiment.

[0017] Figure 10 This is a first diagram showing the primary noise of the blades of the blower according to the third embodiment.

[0018] Figure 11 The second figure shows the noise reduction of the blower according to the third embodiment.

[0019] Figure 12 This is a second figure showing the primary noise of the blades of the blower according to the third embodiment.

[0020] Figure 13 The third figure shows the noise reduction of the blower according to the third embodiment.

[0021] Figure 14 This is the third figure showing the primary noise of the blades of the blower according to the third embodiment.

[0022] Explanation of reference numerals in the attached figures

[0023] 10, 210, 310: Blower; 15: Motor section; 20: Rotor; 40, 240, 340: Casing; 40b: Exhaust port; 43: Top plate section; 43a: Air inlet; 47: Bottom plate section; 50, 250, 350: Inner side; 55: Straight section; 60: Impeller section; 70, 270, 370: Reflector plate; 372: Protrusion; 372c: Corner section; J: Central axis; Li: Axial dimension of the inner side; Lr: Maximum axial dimension of the reflector plate; V1: First imaginary straight line; V2: Second imaginary straight line; α: Central angle (angle); β: Angle of the corner section. Detailed Implementation

[0024] The blower according to an embodiment of the present invention will now be described with reference to the accompanying drawings. It should be noted that the scope of the present invention is not limited to the following embodiments, and modifications can be made freely within the scope of the technical concept of the present invention. Furthermore, in the following drawings, for ease of understanding of the various components, the actual structure may sometimes differ from the scale, quantities, etc.

[0025] In the following description, the Z-axis is shown in each figure. The Z-axis is the direction in which the rotation axis of the impeller part, i.e., the central axis J, extends in the embodiment described below. The central axis J shown in each figure is an imaginary axis. In the following description, the direction in which the central axis J extends, that is, the direction parallel to the Z-axis, is called the "axial direction". The radial direction centered on the central axis J is simply called the "radial direction". The circumferential direction centered on the central axis J is simply called the "circumferential direction". The side in the axial direction where the arrow of the Z-axis points (+Z side) is called the "axial side" or "upper side". The side in the axial direction opposite to the side in the Z-axis direction (-Z side) is called the "axial other side" or "lower side". It should be noted that "upper side" and "lower side" are only names used to describe the relative positional relationship of each part, and the actual configuration relationship may be other than the configuration relationship shown by these names.

[0026] The circumferential direction is represented by arrow θ in each diagram. The side in the circumferential direction that arrow θ points towards (the +θ side) is called the "circumferential side". The side in the circumferential direction opposite to the side in the direction arrow θ points towards (the -θ side) is called the "circumferential side". The circumferential side is the side that moves counterclockwise around the central axis J when viewed from above. The circumferential side is the side that moves clockwise around the central axis J when viewed from above.

[0027] <First Implementation>

[0028] Figure 1 and Figure 2 The blower 10 shown in this embodiment includes a motor unit 15, a housing 40, an impeller unit 60, and a reflector 70. In this embodiment, the blower 10 is a centrifugal fan that delivers air to one circumferential side (+θ side) by rotating the impeller unit 60 around the central axis J.

[0029] like Figure 2 As shown, the housing 40 internally houses the motor section 15 and the impeller section 60. Figure 1 As shown, the outer casing 40 has a first outer casing portion 41, a second outer casing portion 45, an air supply passage 40a, and an exhaust port 40b. Figure 3 As shown, the outer casing 40 has a side wall portion 40d and an inner surface portion 50.

[0030] like Figure 1 As shown, the first outer casing portion 41 is the upper part of the outer casing 40. The first outer casing portion 41 has a first sidewall portion 42, a top plate portion 43, and a first casing opening 41a. That is, the outer casing 40 has a top plate portion 43. Figure 2 As shown, the portion of the inner surface of the first outer casing 41 located radially outward from the impeller portion 60 surrounds the upper side of the air supply passage 40a.

[0031] like Figure 1 As shown, the top plate portion 43 is a generally annular plate extending in a direction orthogonal to the axial direction. When viewed from the axial direction, the top plate portion 43 surrounds the central axis J. When viewed from the axial direction, the radially outer edge of the top plate portion 43 is curved, with the radial distance between it and the central axis J increasing as it approaches the circumferential side (+θ side). Figure 2 As shown, the top plate portion 43 is positioned above the motor portion 15 and the impeller portion 60, specifically on the axial side (+Z side). The top plate portion 43 has an air inlet 43a. The air inlet 43a is a hole that extends axially through the top plate portion 43. Figure 1 As shown, when viewed from the axial direction, the air inlet 43a is approximately circular in shape with the central axis J as the center.

[0032] like Figure 2 As shown, the first sidewall portion 42 is a cylindrical shape extending downward from the radial outer edge of the top plate portion 43. (As shown...) Figure 1 As shown, the first sidewall portion 42 extends circumferentially. Figure 2 As shown, the first sidewall portion 42 has an opening on the lower side. The first sidewall portion 42 is located radially outward from the impeller portion 60. The first sidewall portion 42 surrounds the upper portion of the impeller portion 60 from the radial outward. Figure 1 As shown, the first housing opening 41a opens on one radial or circumferential side (+θ side).

[0033] like Figure 2 As shown, the second outer casing portion 45 is the lower portion of the outer casing 40. The second outer casing portion 45 has a second sidewall portion 46 and a bottom plate portion 47. That is, the outer casing 40 has a bottom plate portion 47. Figure 1 As shown, the second outer casing portion 45 has a second casing opening 45a. (As indicated...) Figure 2 As shown, the portion of the inner surface of the second outer casing 45 located radially outward from the impeller portion 60 surrounds the lower side of the air supply passage 40a.

[0034] The base plate portion 47 is a generally annular plate extending in a direction orthogonal to the axial direction. Viewed axially, the base plate portion 47 surrounds the central axis J. Viewed axially, the radial outer edge of the base plate portion 47 is curved, with the radial distance between it and the central axis J increasing towards the circumferential side (+θ side). The base plate portion 47 is positioned lower than the motor portion 15 and the impeller portion 60, i.e., on the other side of the axial direction (-Z side). A base plate protrusion 47h is provided in the base plate portion 47. The base plate protrusion 47h is a cylindrical shape protruding upward from the base plate portion 47. The base plate protrusion 47h is a generally cylindrical shape centered on the central axis J. The base plate protrusion 47h has an opening at the top.

[0035] The second sidewall portion 46 is a cylindrical shape extending upward from the radial outer edge of the base plate portion 47. For example... Figure 1As shown, the second sidewall portion 46 extends circumferentially. (As indicated...) Figure 2 As shown, the second sidewall portion 46 has an opening on its upper side. The second sidewall portion 46 is located radially outward from the impeller portion 60. The upper end of the second sidewall portion 46 is fixed to the lower end of the first sidewall portion 42. Thus, the second outer casing portion 45 is fixed to the first outer casing portion 41. The second sidewall portion 46 radially surrounds the lower portion of the impeller portion 60. Figure 1 As shown, the second housing opening 45a opens on one radial or circumferential side (+θ side). When viewed axially, the second housing opening 45a overlaps with the first housing opening 41a. In this embodiment, the exhaust port 40b is formed by the first housing opening 41a and the second housing opening 45a. The exhaust port 40b opens on one radial or circumferential side.

[0036] In this embodiment, the sidewall portion 40d is composed of a first sidewall portion 42 and a second sidewall portion 46. For example... Figure 2 As shown, the sidewall portion 40d is located radially outward from the impeller portion 60. The sidewall portion 40d is radially opposed to the impeller portion 60. The sidewall portion 40d axially connects the radially outer edge of the top plate portion 43 and the radially outer edge of the bottom plate portion 47. Figure 1 As shown, the sidewall portion 40d extends circumferentially along the radial outer edges of both the top plate portion 43 and the bottom plate portion 47. Figure 2 As shown, the sidewall portion 40d surrounds the air supply passage 40a from the radially outer side. The inner surface 50 is the radially inner surface of the sidewall portion 40d. The inner surface 50 will be described in detail later.

[0037] Airflow passage 40a is the space within the housing 40 where air flows through the impeller portion 60 as it rotates around the central axis J. Airflow passage 40a is the space within the housing 40 located radially outward from the impeller portion 60. Airflow passage 40a is the space surrounded by the top plate portion 43, the bottom plate portion 47, and the side wall portion 40d. Figure 3 As shown, the air supply path 40a extends circumferentially. Arrow AF indicates the airflow within the air supply path 40a. Air flowing in the air supply path 40a towards the circumferential side (+θ side) due to the rotation of the impeller portion 60 around the central axis J flows out to the outside of the blower 10 via the exhaust port 40b. That is, the exhaust port 40b discharges air to the outside of the blower 10.

[0038] like Figure 2 As shown, the impeller section 60 has a cup section 61 and a plurality of blades 64. The cup section 61 internally houses the motor section 15. Figure 1 As shown, multiple blades 64 are spaced apart along the circumference.

[0039] like Figure 2As shown, the motor unit 15 is housed inside the cup unit 61. The motor unit 15 is fixed to the inner surface of the bottom plate protrusion 47h. Thus, the motor unit 15 is connected to the housing 40. The motor unit 15 has a rotor 20. The rotor 20 rotates around the central axis J. The impeller unit 60 is fixed to the rotor 20. Therefore, when the rotor 20 rotates around the central axis J, the impeller unit 60 can rotate together with the rotor 20 around the central axis J.

[0040] In this embodiment, the impeller section 60 and the rotor 20 rotate together about the central axis J towards one circumferential side (+θ side). When the impeller section 60 rotates about the central axis J, air is drawn through... Figure 1 The air inlet 43a shown is drawn into the interior of the housing 40. (As shown) Figure 3 As indicated by arrow AF, air is delivered radially outward and circumferentially to one side from the impeller portion 60 through multiple blades 64, flowing in the air supply path 40a. The air flowing in the air supply path 40a is then discharged to the outside of the blower 10 via the exhaust port 40b. Therefore, the airflow volume flowing in the air supply path 40a increases towards the circumferential side. Consequently, the airflow volume near the exhaust port 40b is large. Furthermore, the air velocity flowing in the air supply path 40a increases towards the circumferential side. Consequently, the air velocity near the exhaust port 40b is high.

[0041] like Figure 2 As shown, in this embodiment, the reflector 70 is a plate-shaped part that protrudes axially from the top plate portion 43. More specifically, the reflector 70 protrudes downward from the top plate portion 43, that is, to the other axial side (-Z side). That is, the reflector 70 protrudes axially from either the top plate portion 43 or the bottom plate portion 47. In this embodiment, the reflector 70 and the bottom plate portion 47 are axially spaced apart. That is, the reflector 70 and the other of the top plate portion 43 and the bottom plate portion 47 are axially spaced apart. In this embodiment, the reflector 70 and the first outer shell portion 41 are part of the same component. The reflector 70 and the first outer shell portion 41 can also be separate components. In this case, the reflector 70 can be glued to the top plate portion 43 or fixed to the top plate portion 43 by welding or the like.

[0042] like Figure 3 As shown, the reflector 70 is radially disposed between the impeller portion 60 and the inner surface 50 of the housing 40. The reflector 70 extends circumferentially. The reflector 70 has a first end 70a and a second end 70c. The first end 70a is the end of the reflector 70 on one circumferential side (+θ side). The second end 70c is the end of the reflector 70 on the other circumferential side (-θ side). Figure 3 The first imaginary line V1 shown is an imaginary line that passes through the first end 70a and the central axis J when viewed from the axial direction. Figure 3The second imaginary line V2 shown is an imaginary line that passes through the second end 70c and the central axis J when viewed from the axial direction. In this embodiment, when viewed from the axial direction, the angle α formed by the first imaginary line V1 and the second imaginary line V2, i.e., the central angle α, is 90° or more and 180° or less. It should be noted that the central angle α can be less than 90° or greater than 180°. The portion of the reflector 70 on the other circumferential side extends circumferentially at a certain radial distance G1 from the inner surface 50. That is, at least a portion of the reflector 70 extends circumferentially at a certain radial distance G1 from the inner surface 50.

[0043] As described above, the inner surface 50 is the radially inward-facing surface of the sidewall portion 40d. When viewed axially, the inner surface 50 is a curved shape in which the radial distance between it and the central axis J increases as it approaches the circumferential side (+θ side). The inner surface 50 has a first inner surface 51, a second inner surface 53, and a straight portion 55.

[0044] The first inner surface 51 is the portion of the inner surface 50 located radially outward of the reflector 70. The reflector 70 is disposed between the first inner surface 51 and the impeller portion 60. The first inner surface 51 is the portion of the inner surface 50 that overlaps with the reflector 70 when viewed from the central axis J. The first inner surface 51 is located between a first imaginary line V1 and a second imaginary line V2. Figure 2 As shown, the first inner surface 51 has a first portion 51a and a second portion 51c.

[0045] The first part 51a is the portion of the first inner surface 51 that is axially higher than the lower end of the reflector 70. The first part 51a is radially opposed to the reflector 70. The second part 51c is the portion of the first inner surface 51 that is axially lower than the lower end of the reflector 70. The second part 51c is not radially opposed to the reflector 70, but radially opposed to the impeller portion 60. Thus, a portion of the inner surface 50 is radially opposed to the impeller portion 60, and another portion of the inner surface 50 is radially opposed to the reflector 70.

[0046] like Figure 3 As shown, the second inner surface 53 is the portion of the inner surface 50 that is radially opposite to the first inner surface 51 across the central axis J. The reflector 70 is not positioned between the second inner surface 53 and the impeller portion 60. The second inner surface 53 does not overlap with the reflector 70 when viewed from the central axis J. Figure 2 As shown, the second inner surface 53 has a third portion 53a and a fourth portion 53c.

[0047] The third part 53a is the portion of the second inner surface 53 that is axially higher than the lower end of the reflector 70. The third part 53a is radially opposed to the reflector 70 across the impeller portion 60. The radial distance between the third part 53a and the reflector 70, i.e., the second distance L2, is shorter than the radial distance between the second inner surface 53 and the first inner surface 51, i.e., the first distance L1. That is, the second distance L2 and the first distance L1 are different from each other.

[0048] The fourth part 53c is the portion of the second inner surface 53 that is axially lower than the lower end of the reflector 70. The fourth part 53c is radially opposed to the second part 51c, separated by the impeller portion 60. The radial distance between the fourth part 53c and the second part 51c is a first distance L1. The radial distance between the fourth part 53c and the second part 51c, which are radially opposed in the inner surface 50, separated by the impeller portion 60, i.e., the first distance L1, and the radial distance between the third part 53a, which is the portion of the inner surface 50 that is radially opposed to the reflector 70, separated by the impeller portion 60, and the reflector 70, i.e., the second distance L2, are different. In other words, the radial distance between the portions of the inner surface 50 that are radially opposed to each other, separated by the impeller portion 60, i.e., the first distance L1, and the radial distance between the portion of the inner surface 50 that is radially opposed to the reflector 70, separated by the impeller portion 60, and the reflector 70, i.e., the second distance L2, are different.

[0049] When the blower 10 operates, the impeller portion 60 rotates around the central axis J, and as described above, sound waves are generated when each blade 64 delivers air radially outward and to one circumferential side (+θ side). As these sound waves propagate radially, they resonate between the fourth portion 53c and the second portion 51c, and between the reflector 70 and the third portion 53a. In this embodiment, as described above, the radial distance between the fourth portion 53c and the second portion 51c (the first distance L1) and the radial distance between the third portion 53a and the reflector 70 (the second distance L2) are different. Therefore, the frequencies of the first sound wave S1 resonating between the fourth portion 53c and the second portion 51c and the second sound wave S2 resonating between the reflector 70 and the third portion 53a are different. Therefore, when the first sound wave S1 and the second sound wave S2 interfere with each other, they cancel each other out, thus reducing the intensity of the first sound wave S1 and the intensity of the second sound wave S2, respectively. Therefore, the noise during the operation of the blower 10 can be appropriately suppressed.

[0050] like Figure 3As shown, the straight section 55 is the portion of the inner surface 50 that includes the end on the circumferential side (+θ side). When viewed axially, the straight section 55 extends in a straight line. The straight section 55 is connected to the exhaust port 40b. When viewed radially, the portion of the reflector 70 on the circumferential side overlaps with the straight section 55. That is, when viewed radially, a portion of the reflector 70 overlaps with the straight section 55. As described above, in this embodiment, the airflow volume flowing in the air supply path 40a increases towards the circumferential side, and the airflow velocity flowing in the air supply path 40a increases towards the circumferential side. Therefore, the sound waves generated when each blade 64 directs air radially outward and circumferentially towards the exhaust port 40b increase towards it. Therefore, the intensity of the sound waves generated near the straight section 55, which is the portion of the inner surface 50 connected to the exhaust port 40b, is high.

[0051] According to this embodiment, the blower 10 includes: a motor section 15 having a rotor 20 that rotates about a central axis J; an impeller section 60 that rotates together with the rotor 20; a housing 40 that internally houses the impeller section 60; and a reflector 70 that is radially disposed between the impeller section 60 and the inner surface 50 of the housing 40 and extends circumferentially. A portion of the inner surface 50 is radially opposed to the impeller section 60, and another portion of the inner surface 50 is radially opposed to the reflector 70. As described above, when the impeller section 60 rotates about the central axis J, sound waves are generated when air is expelled by each blade 64. In this embodiment, as described above, the radial distance between the radially opposed portions of the inner surface 50 that are separated from the impeller section 60, i.e., a first distance L1, and the radial distance between the portion of the inner surface 50 that is separated from the impeller section 60 and the reflector 70, i.e., a second distance L2, are different. Therefore, as described above, the frequencies of the first sound wave S1 resonating between the portions of the inner surface 50 opposite each other across the impeller portion 60 and the second sound wave S2 resonating between the portion of the inner surface 50 opposite the impeller portion 60 and the reflector 70 are different. Thus, as described above, by the mutual interference of the first sound wave S1 and the second sound wave S2, the intensity of the first sound wave S1 and the intensity of the second sound wave S2 can be reduced respectively. Therefore, the noise of the blower 10 can be appropriately suppressed.

[0052] According to this embodiment, the housing 40 includes: a top plate portion 43 disposed above the impeller portion 60, i.e., on one axial side (+Z side); and a bottom plate portion 47 disposed below the impeller portion 60, i.e., on the other axial side (-Z side). The reflector 70 protrudes axially from one of the top plate portion 43 and the bottom plate portion 47 and is axially spaced apart from the other of the top plate portion 43 and the bottom plate portion 47. Therefore, the radial distance between the fourth portion 53c, which is the part of the second inner surface 53 that is radially opposed to the first inner surface 51 across the impeller portion 60, and the second portion 51c, and the radial distance between the third portion 53a, which is the part of the second inner surface 53 that is radially opposed to the reflector 70 across the impeller portion 60, and the reflector 70, i.e., the second distance L2, are different from each other. Therefore, the frequencies of the first sound wave S1 resonating between the fourth part 53c and the second part 51c and the second sound wave S2 resonating between the third part 53a and the reflector 70 are different. Thus, as described above, by the mutual interference of the first sound wave S1 and the second sound wave S2, the intensity of the first sound wave S1 and the intensity of the second sound wave S2 can be reduced respectively. Therefore, the noise of the blower 10 can be appropriately suppressed.

[0053] According to this embodiment, the top plate portion 43 has an air inlet 43a that extends through the top plate portion 43 axially, and the reflector 70 protrudes downward from the top plate portion 43, i.e., on the other side of the axial direction (-Z side), and is axially spaced apart from the bottom plate portion 47. Therefore, as described above, the first distance L1 and the second distance L2 can be different distances. Therefore, as described above, the frequency of the first sound wave S1 resonating between the fourth portion 53c and the second portion 51c and the frequency of the second sound wave S2 resonating between the third portion 53a and the reflector 70 are different. Thus, as described above, the intensity of the first sound wave S1 and the intensity of the second sound wave S2 can be reduced respectively. Therefore, the noise of the blower 10 can be appropriately suppressed.

[0054] According to this embodiment, when viewed from the axial direction, the inner surface 50 is curved, with the radial distance between it and the central axis J increasing as it moves towards the circumferential side (+θ side). At least a portion of the reflector 70 extends circumferentially, separated from the inner surface 50 by a certain radial interval G1. As described above, noise can be suppressed by the interference of the first sound wave S1 and the second sound wave S2. Furthermore, since the inner surface 50 is curved, the radial distance between the second inner surface 53 and the reflector 70 changes continuously in the circumferential direction. This disperses the frequency of the second sound wave S2 resonating between them, suppressing the increase in the intensity of sound waves at specific frequencies. Therefore, the noise of the blower 10 can be suppressed more appropriately.

[0055] According to this embodiment, the outer casing 40 has an exhaust port 40b for discharging air to the outside, and the inner surface 50 has a straight portion 55 connected to the exhaust port 40b and extending in a straight line when viewed axially. When viewed radially, a portion of the reflector 70 overlaps with the straight portion 55. Therefore, the reflector 70 can be positioned close to the exhaust port 40b. As described above, the sound waves generated when air is expelled by each blade 64 increase in intensity as they approach the exhaust port 40b. In this embodiment, since the reflector 70 can be positioned close to the exhaust port 40b, the intensity of the partially resonant sound waves near the exhaust port 40b of the outer casing 40 can be appropriately reduced. Therefore, the noise of the blower 10 can be suppressed more appropriately.

[0056] According to this embodiment, when viewed from the axial direction, the angle α formed by the first imaginary line V1 passing through the first end 70a (the end on the circumferential side, +θ side) and the central axis J of the reflector 70, and the second imaginary line V2 passing through the second end 70c (the end on the other circumferential side, -θ side) and the central axis J, i.e., the central angle α, is 90° or more. Therefore, the circumferential dimension of the reflector 70 can be prevented from becoming too small. Consequently, the circumferential range within which the intensity of the first sound wave S1 and the intensity of the second sound wave S2 can be reduced by suppressing interference between the first sound wave S1 and the second sound wave S2 can become too narrow. Therefore, the noise of the blower 10 can be suppressed more appropriately.

[0057] According to this embodiment, when viewed axially, the angle α formed by the first imaginary straight line V1 passing through the first end 70a of the reflector 70 and the central axis J, and the second imaginary straight line V2 passing through the second end 70c of the reflector 70 and the central axis J, i.e., the central angle α, is 180° or less. Therefore, it is possible to suppress the reflectors 70 from being radially opposed to each other with the impeller portion 60 between them. This, in turn, suppresses the resonance of sound waves between the reflectors 70. Therefore, it is possible to more appropriately suppress the noise of the blower 10.

[0058] <Second Implementation>

[0059] Figure 4 This is a cross-sectional view showing the blower 210 of this embodiment. In the following description, the same reference numerals are used to denote the constituent elements that are the same as those in the first embodiment described above, and their descriptions are omitted. Figure 4 The blower 210 of this embodiment shown includes a motor unit 15, a housing 240, an impeller unit 60, and a reflector 270. The blower 210 is a centrifugal fan that delivers air to one circumferential direction (+θ side) by rotating the impeller unit 60 around the central axis J.

[0060] The housing 240 internally houses the motor section 15 and the impeller section 60. The housing 240 has a first housing section 241, a second housing section 245, an air supply passage 40a, and an exhaust port 40b (see reference). Figure 1 ).like Figure 5 As shown, the housing 240 has a side wall portion 40d and an inner surface portion 250.

[0061] The first outer casing portion 241 is the upper portion of the outer casing 240. The first outer casing portion 241 has a first sidewall portion 42, a top plate portion 43, and a first casing opening portion 41a (see reference). Figure 1 The top plate portion 43 has an air inlet 43a extending axially through the top plate portion 43. The second outer casing portion 245 is the lower part of the outer casing 240. The second outer casing portion 245 has a second side wall portion 46, a bottom plate portion 47, and a second casing opening portion 45a (see reference). Figure 1 The sidewall portion 40d is composed of a first sidewall portion 42 and a second sidewall portion 46. The inner surface 250 is the radially inward surface of the sidewall portion 40d. The inner surface 250 will be described in detail later. Other configurations of the housing 240 in this embodiment are the same as those of the housing 40 in the first embodiment described above.

[0062] In this embodiment, the reflector 270 is a plate-shaped part that protrudes axially from the base plate portion 47. More specifically, the reflector 270 protrudes upward from the base plate portion 47, i.e., axially (+Z side). That is, the reflector 270 protrudes axially from either the top plate portion 43 or the base plate portion 47. In this embodiment, the reflector 270 and the top plate portion 43 are axially spaced apart. That is, the reflector 270 and the other of the top plate portion 43 and the base plate portion 47 are axially spaced apart. In this embodiment, the reflector 270 and the second outer shell portion 245 are part of the same component. The reflector 270 and the second outer shell portion 245 can also be separate components. In this case, the reflector 270 can be glued to the base plate portion 47 or fixed to the base plate portion 47 by welding or the like.

[0063] like Figure 5 As shown, the reflector 270 is radially disposed between the impeller portion 60 and the inner surface 250 of the housing 240. The reflector 270 extends circumferentially. The reflector 270 has a first end 270a and a second end 270c. The first end 270a is the end of the reflector 270 on one circumferential side (+θ side). The second end 270c is the end of the reflector 270 on the other circumferential side (-θ side). Figure 5 The first imaginary line V1 shown is an imaginary line that passes through the first end 270a and the central axis J when viewed from the axial direction. Figure 5The second imaginary line V2 shown is an imaginary line that passes through the second end 270c and the central axis J when viewed from the axial direction. In this embodiment, when viewed from the axial direction, the angle α formed by the first imaginary line V1 and the second imaginary line V2, i.e., the central angle α, is 90° or more and 180° or less. The portion of the reflector 270 on the other circumferential side extends circumferentially from the impeller portion 60 at a radial distance G2. That is, at least a portion of the reflector 270 extends circumferentially from the impeller portion 60 at a radial distance G2.

[0064] As described above, the inner surface 250 is the radially inward surface of the sidewall portion 40d. When viewed axially, the inner surface 250 is a curved shape in which the radial distance between it and the central axis J increases as it approaches the circumferential side (+θ side). The inner surface 250 has a first inner surface 251, a second inner surface 253, and a straight portion 55.

[0065] The first inner surface 251 is the portion of the inner surface 250 located radially outward of the reflector 270. The reflector 270 is disposed between the first inner surface 251 and the impeller portion 60. The first inner surface 251 is the portion of the inner surface 250 that overlaps with the reflector 270 when viewed from the central axis J. The first inner surface 251 is located between a first imaginary line V1 and a second imaginary line V2. Figure 4 As shown, the first inner surface 251 has a first portion 251a and a second portion 251c.

[0066] The first part 251a is the portion of the first inner surface 251 that is axially lower than the upper end of the reflector 270. The first part 251a is radially opposed to the reflector 270. The second part 251c is the portion of the first inner surface 251 that is axially higher than the upper end of the reflector 270. The second part 251c is not radially opposed to the reflector 270, but radially opposed to the impeller portion 60. Thus, a portion of the inner surface 250 is radially opposed to the impeller portion 60, and another portion of the inner surface 250 is radially opposed to the reflector 270.

[0067] like Figure 5 As shown, the second inner surface 253 is the portion of the inner surface 250 that is radially opposite to the first inner surface 251 across the central axis J. The reflector 270 is not positioned between the second inner surface 253 and the impeller portion 60. The second inner surface 253 does not overlap with the reflector 270 when viewed from the central axis J. Figure 4 As shown, the second inner surface 253 has a third portion 253a and a fourth portion 253c.

[0068] The third part 253a is the portion of the second inner surface 253 that is axially lower than the upper end of the reflector 270. The third part 253a is radially opposed to the reflector 270 across the impeller portion 60. The radial distance between the third part 253a and the reflector 270, i.e., the second distance L2, is shorter than the radial distance between the second inner surface 253 and the first inner surface 251, i.e., the first distance L1. That is, the second distance L2 and the first distance L1 are different from each other.

[0069] The fourth part 253c is the portion of the first inner surface 253 that is axially positioned above the upper end of the reflector 270. The fourth part 253c is radially opposed to the second part 251c, separated by the impeller portion 60. The radial distance between the fourth part 253c and the second part 251c is a first distance L1. The radial distance between the fourth part 253c and the second part 251c, which are radially opposed in the inner surface 250 separated by the impeller portion 60, i.e., the first distance L1, and the radial distance between the third part 253a, which is the portion of the inner surface 250 that is radially opposed to the reflector 270 separated by the impeller portion 60, and the reflector 270, i.e., the second distance L2, are different. In other words, the radial distance between the radially opposing portions of the inner surface 250 separated by the impeller portion 60, i.e., the first distance L1, and the radial distance between the radially opposing portions of the inner surface 250 separated by the impeller portion 60 and the reflector 270, i.e., the second distance L2, are different. Other configurations of the blower 210 in this embodiment are the same as those of the blower 10 in the first embodiment described above.

[0070] When the blower 210 operates, the impeller portion 60 rotates around the central axis J, and as described above, sound waves are generated when each blade 64 delivers air radially outward and to one circumferential side (+θ side). As these sound waves propagate radially, they resonate between the fourth portion 253c and the second portion 251c, and between the reflector 270 and the third portion 253a. In this embodiment, as described above, the radial distance between the fourth portion 253c and the second portion 251c, i.e., the first distance L1, and the radial distance between the third portion 253a and the reflector 270, i.e., the second distance L2, are different from each other. Therefore, the frequency of the first sound wave S1 resonating between the fourth portion 253c and the second portion 251c, and the frequency of the second sound wave S2 resonating between the reflector 270 and the third portion 253a, are different from each other. Therefore, when the first sound wave S1 and the second sound wave S2 interfere with each other, the first sound wave S1 and the second sound wave S2 cancel each other out, thus reducing the intensity of the first sound wave S1 and the intensity of the second sound wave S2 respectively. Therefore, the noise during the operation of the blower 210 can be appropriately suppressed.

[0071] As described above, when the impeller section 60 rotates around the central axis J, as Figure 4 As indicated by arrow AF, air drawn into the interior of the housing 240 via the inlet 43a is discharged from the impeller section 60 radially outward and circumferentially to one side (+θ side) through multiple blades 64, flowing in the air supply path 40a. The airflow discharged from the impeller section 60 to the air supply path 40a increases towards the lower side. Therefore, the airflow flowing between each blade 64 increases towards the lower side. Consequently, the sound waves generated when each blade 64 discharges air into the air supply path 40a increase towards the lower side.

[0072] According to this embodiment, the top plate portion 43 has an air inlet 43a extending axially through the top plate portion 43, and the reflector 270 protrudes upward from the bottom plate portion 47, i.e., on one axial side (+Z side), and is axially spaced from the top plate portion 43. As described above, the air volume delivered from the impeller portion 60 to the air supply path 40a increases towards the lower side. Therefore, as described above, the sound waves generated when each blade 64 delivers air to the air supply path 40a increase towards the lower side. In contrast, in this embodiment, the reflector 270 protrudes upward from the bottom plate portion 47, thus appropriately reducing the intensity of the sound waves resonating partially on the lower side of the housing 240. Therefore, the noise of the blower 210 can be appropriately reduced.

[0073] According to this embodiment, when viewed from the axial direction, the inner surface 250 is curved, with the radial distance between it and the central axis J increasing as it approaches the circumferential side (+θ side). At least a portion of the reflector 270 extends circumferentially, separated from the impeller portion 60 by a certain radial interval G2. As described above, noise can be suppressed by the interference of the first sound wave S1 and the second sound wave S2. Furthermore, since the inner surface 250 is curved, the radial distance between the second inner surface 253 and the reflector 270 changes continuously in the circumferential direction. This disperses the frequency of the second sound wave S2 resonating between them, suppressing the increase in intensity of sound waves of a specific frequency. Thus, the increase in intensity of sound waves of a specific frequency can be appropriately suppressed between the second inner surface 253 and the reflector 270. Therefore, the noise of the blower 210 can be suppressed more appropriately.

[0074] <Third Implementation Method>

[0075] Figure 6 This is a cross-sectional view showing the blower 310 of this embodiment. In the following description, the same reference numerals are used to denote the constituent elements that are the same as those in the first embodiment described above, and their descriptions are omitted. Figure 6The blower 310 shown in this embodiment includes a motor unit 15, a housing 340, an impeller unit 60, and a reflector 370. The blower 310 is a centrifugal fan that delivers air to one circumferential direction (+θ side) by rotating the impeller unit 60 around the central axis J.

[0076] The housing 340 internally houses the motor section 15 and the impeller section 60. The housing 340 has a first housing section 341, a second housing section 45, an air supply passage 40a, and an exhaust port 40b (see reference). Figure 1 ).like Figure 7 As shown, the housing 340 has a side wall portion 40d and an inner surface portion 350.

[0077] like Figure 6 As shown, the first outer casing portion 341 is the upper part of the outer casing 340. The first outer casing portion 341 has a first sidewall portion 42, a top plate portion 43, and a first casing opening portion 41a (see reference). Figure 1 The top plate portion 43 has an air inlet 43a extending axially through the top plate portion 43. The second outer casing portion 45 is the lower part of the outer casing 340. The second outer casing portion 45 has a second side wall portion 46, a bottom plate portion 47, and a second casing opening portion 45a (see reference). Figure 1 The sidewall portion 40d is composed of a first sidewall portion 42 and a second sidewall portion 46. The inner surface 350 is the radially inward surface of the sidewall portion 40d. The inner surface 350 will be described in detail later. Other configurations of the housing 340 in this embodiment are the same as those of the housing 40 in the first embodiment described above.

[0078] In this embodiment, the reflector 370 is a plate-shaped part that protrudes axially from the top plate portion 43. More specifically, the reflector 370 protrudes downward from the top plate portion 43, that is, to the other axial side (-Z side). That is, the reflector 370 protrudes axially from either the top plate portion 43 or the bottom plate portion 47. In this embodiment, the reflector 370 and the bottom plate portion 47 are axially spaced apart. That is, the reflector 370 and the other of the top plate portion 43 and the bottom plate portion 47 are axially spaced apart. In this embodiment, the reflector 370 and the first outer shell portion 341 are part of the same component. The reflector 370 and the first outer shell portion 341 can also be separate components. In this case, the reflector 370 can be glued to the top plate portion 43 or fixed to the top plate portion 43 by welding or the like. In this embodiment, the ratio of the maximum axial dimension Lr of the reflector 370 to the axial dimension Li of the inner surface 350, i.e., the dimension ratio Rs, is 37.5% or more and 55.0% or less. The dimension ratio Rs may also be less than 37.5% or greater than 55.0%. The dimension ratio Rs is preferably around 50.0%.

[0079] like Figure 7 As shown, the reflector 370 is radially disposed between the impeller portion 60 and the inner side surface 350 of the housing 340. The reflector 370 extends circumferentially. The reflector 370 has a first end 370a and a second end 370c. The first end 370a is the end of the reflector 370 on one circumferential side (+θ side). The first end 370a is disposed at a position on the other circumferential side (-θ side) than the straight portion 55. The second end 370c is the end of the reflector 370 on the other circumferential side (-θ side). Figure 7 The first imaginary line V1 shown is an imaginary line that passes through the first end 370a and the central axis J when viewed from the axial direction. Figure 7 The third imaginary line V3 shown is an imaginary line that passes through the end of the straight section 55 on the other side of the circumference and the central axis J. In this embodiment, when viewed from the axial direction, the angle γ formed by the first imaginary line V1 and the third imaginary line V3 is preferably 20° or more and 50° or less. Figure 7 The second imaginary line V2 shown is an imaginary line that passes through the second end 370c and the central axis J when viewed from the axial direction. In this embodiment, when viewed from the axial direction, the angle α formed by the first imaginary line V1 and the second imaginary line V2, i.e., the central angle α, is 15° or more and 30° or less. The central angle α may also be less than 15° or greater than 30°. In this embodiment, the central angle α is preferably about 25°. The reflector 370 extends circumferentially at a radially spaced interval G1 from the inner surface 350. That is, at least a portion of the reflector 370 extends circumferentially at a radially spaced interval G1 from the inner surface 350. At least a portion of the reflector 370 may also extend circumferentially at a radially spaced interval from the impeller portion 60. Figure 8 As shown, the reflector 370 has a central portion 371, a protrusion 372, and a rear portion 373.

[0080] The central portion 371 is the circumferentially central part of the reflector 370. The central portion 371 is a plate extending circumferentially. The plate surface of the central portion 371 faces radially. When viewed radially, the central portion 371 is a roughly rectangular shape with its long side extending circumferentially. The upper end of the central portion 371 is connected to the top plate portion 43. The axial dimension of the central portion 371 is the maximum axial dimension Lr of the reflector 370.

[0081] The protrusion 372 is the portion on the other circumferential side (-θ side) of the reflector 370. The protrusion 372 is a plate-shaped portion protruding circumferentially from the end of the central portion 371 on the other circumferential side. The plate surface of the protrusion 372 faces radially. When viewed radially, the protrusion 372 is approximately a right-angled triangle. When viewed radially, the hypotenuse of the protrusion 372 is positioned on the upper side as the portion from the lower end of the central portion 371 moves towards the other circumferential side. The upper end of the protrusion 372 is connected to the top plate portion 43. The axial dimension of the protrusion 372 increases as it moves circumferentially from the second end 370c, i.e., the end of the reflector 370 on the other circumferential side, towards the circumferential side (+θ side). The axial dimension of the end of the protrusion 372 on the circumferential side is the maximum axial dimension Lr of the reflector 370. The protrusion 372 has a top surface 372a and a corner portion 372c.

[0082] The top surface 372a is a plane on the outer surface of the protrusion 372 between the circumferential side (-θ side) and the lower side. The end of the top surface 372a on the circumferential side is connected to the lower side surface of the top plate portion 43. The end of the top surface 372a on the circumferential side (+θ side) is connected to the end of the central portion 371 on the circumferential side and the lower side.

[0083] The corner portion 372c is the corner portion of the end portion on the other side (-θ side) of the protrusion 372 in the circumferential direction. In this embodiment, when viewed radially, the angle β of the corner portion 372c is 40° or more and 60° or less. The angle β of the corner portion 372c may also be less than 40° or greater than 60°. In this embodiment, the angle β of the corner portion 372c is preferably about 45°.

[0084] The rear end portion 373 is the circumferential side (+θ side) of the reflector 370. The rear end portion 373 is a plate-shaped portion protruding circumferentially from the end of the central portion 371. The plate surface of the rear end portion 373 faces radially. When viewed radially, the rear end portion 373 is approximately a right-angled triangle. When viewed radially, the hypotenuse of the rear end portion 373 is positioned at the upper side as the portion from the lower end of the central portion 371 tends towards the circumferential side. The upper end of the rear end portion 373 is connected to the top plate portion 43. The axial dimension of the rear end portion 373 increases as it tends towards the other circumferential side (-θ side) from the first end portion 370a, i.e., the end of the reflector 370 on the circumferential side. It should be noted that the shape of the rear end portion 373 is not limited to this embodiment; it may also be rectangular when viewed radially. Other configurations of the reflector 370 in this embodiment are the same as those of the reflector 70 in the first embodiment described above.

[0085] As described above, the inner surface 350 is the surface of the sidewall portion 40d facing radially inward. Figure 7 As shown, when viewed from the axial direction, the inner surface 350 is a curve whose radial distance from the central axis J increases as it moves toward the circumferential side (+θ side). The inner surface 350 has a first inner surface 351, a second inner surface 353, and a straight portion 55.

[0086] The first inner surface 351 is the portion of the inner surface 350 located radially outward from the reflector 370. The reflector 370 is disposed between the first inner surface 351 and the impeller portion 60. When viewed axially, the first inner surface 351 lies between a first imaginary line V1 and a second imaginary line V2. Figure 6 As shown, the first inner surface 351 has a first portion 351a and a second portion 351c.

[0087] The first part 351a is the portion of the first inner surface 351 that is axially higher than the lower end of the reflector 370. The first part 351a is radially opposed to the reflector 370. The second part 351c is the portion of the first inner surface 351 that is axially lower than the lower end of the reflector 370. The second part 351c is not radially opposed to the reflector 370, but radially opposed to the impeller portion 60. Thus, a portion of the inner surface 350 is radially opposed to the impeller portion 60, and another portion of the inner surface 350 is radially opposed to the reflector 370.

[0088] like Figure 7 As shown, the second inner surface 353 is the portion of the inner surface 350 that is radially opposite to the first inner surface 351 across the central axis J. The reflector 370 is not positioned between the second inner surface 353 and the impeller portion 60. The second inner surface 353 does not overlap with the reflector 370 when viewed from the central axis J. Figure 6 As shown, the second inner surface 353 has a third portion 353a and a fourth portion 353c.

[0089] The third part 353a is the portion of the second inner surface 353 that is axially positioned above the lower end of the reflector 370. The third part 353a is radially opposed to the reflector 370, separated by the impeller portion 60. The radial distance L2 between the third part 353a and the reflector 370 is shorter than the radial distance L1 between the second inner surface 353 and the first inner surface 351. That is, the second distance L2 and the first distance L1 are different.

[0090] The fourth portion 353c is the portion of the second inner surface 353 that is axially lower than the lower end of the reflector 370. The fourth portion 353c is radially opposed to the second portion 351c, separated by the impeller portion 60. The radial distance between the fourth portion 353c and the second portion 351c is a first distance L1. As described above, the first distance L1 and the second distance L2 are different from each other. Other configurations of the blower 310 in this embodiment are the same as those of the blower 10 in the first embodiment described above.

[0091] When the blower 310 operates, the impeller portion 60 rotates around the central axis J, and as described above, sound waves are generated when each blade 64 delivers air radially outward and to one circumferential side (+θ side). As these sound waves propagate radially, they resonate between the fourth portion 353c and the second portion 351c, and between the reflector 370 and the third portion 353a. In this embodiment, as described above, the radial distance between the fourth portion 353c and the second portion 351c, i.e., the first distance L1, and the radial distance between the third portion 353a and the reflector 370, i.e., the second distance L2, are different from each other. Therefore, the frequency of the first sound wave S1 resonating between the fourth portion 353c and the second portion 351c, and the frequency of the second sound wave S2 resonating between the reflector 370 and the third portion 353a, are different from each other. Therefore, when the first sound wave S1 and the second sound wave S2 interfere with each other, the first sound wave S1 and the second sound wave S2 cancel each other out, thus reducing the intensity of the first sound wave S1 and the intensity of the second sound wave S2 respectively. Therefore, the noise during the operation of the blower 310 can be appropriately suppressed.

[0092] The noise reduction effect of the blower 310 in this embodiment will be explained below. Figure 9 The first figure shows the noise reduction Nd of the blower 310 in this embodiment. Figure 9 The horizontal axis is the center angle α. Figure 9 The vertical axis represents the noise reduction amount Nd. In this embodiment, the noise reduction amount Nd is calculated by subtracting the 4000Hz noise from the noise generated by the blower 310 without the reflector 370 from the 4000Hz noise generated by the blower without the reflector 370. That is, the noise reduction amount Nd is the magnitude of the 4000Hz noise that can be reduced by the blower 310 having the reflector 370. The larger the noise reduction amount Nd, the greater the noise reduction effect achieved by the reflector 370; the smaller the noise reduction amount Nd, the smaller the noise reduction effect achieved by the reflector 370.

[0093] like Figure 9As shown, the noise reduction Nd increases as the center angle α increases when the center angle α is 25° or less, and remains approximately the same when the center angle α is 25° or more but less than 90°. The noise reduction Nd is positive within the range where the center angle α is 90° or less. Therefore, in this embodiment, when the center angle α of the reflector 370 is 90° or less, noise at a frequency of 4000Hz can be reduced by the reflector 370. As described above, in this embodiment, the center angle α is 15° or more but less than 30°, therefore, the blower 310 can reduce noise at a frequency of 4000Hz by including the reflector 370.

[0094] Figure 10 The first figure shows the primary noise Nw of the blades of the blower 310 in this embodiment. Figure 10 The horizontal axis is the center angle α. Figure 10 The longitudinal axis represents the primary blade noise Nw. In this embodiment, the primary blade noise Nw is the noise with a frequency of 3000 Hz generated in the blower 310. In this embodiment, the number of blades 64 in the impeller section 60 multiplied by the rotational speed (rps) of the impeller section 60 is approximately 3000. Air drawn into the interior of the housing 340 through the air inlet 43a is delivered from the impeller section 60 radially outward and circumferentially to one side (+θ side) through each blade 64. Therefore, when the impeller section 60 rotates about the central axis J, the intensity of the air delivered toward the reflector 370 varies about 3000 times per second, generating the primary blade noise Nw as a noise of 3000 Hz.

[0095] like Figure 10 As shown, the primary blade noise Nw is approximately the same when the center angle α is 35° or less; it increases as the center angle α increases when the center angle α is 35° or more and 60° or less; and it remains approximately the same when the center angle α is 60° or more and 90° or less. As described above, in this embodiment, the center angle α is 15° or more and 30° or less. Therefore, in this embodiment, compared to the case where the center angle α is 35° or more, the increase in primary blade noise Nw can be suppressed. As described above, in this embodiment, the center angle α is 15° or more and 30° or less, thus noise at a frequency of 4000Hz can be reduced. Therefore, in this embodiment, the center angle α is 15° or more and 30° or less, thus the increase in primary blade noise Nw can be suppressed, and noise at a frequency of 4000Hz can be reduced.

[0096] In this embodiment, in order to increase the noise reduction Nd and reduce the primary noise Nw of the blade, the center angle α is preferably 10° or more and 60° or less, more preferably 15° or more and 45° or less, and even more preferably 25° or more and 35° or less.

[0097] Figure 11 The second figure shows the noise reduction Nd of the blower 310 in this embodiment. Figure 11 The horizontal axis is the angle β of the corner 372c. Figure 11 The vertical axis represents the noise reduction Nd. For example... Figure 11 As shown, the noise reduction Nd increases as the angle β of corner 372c increases within the range of 30° to 60°. The noise reduction Nd is positive within the range of 30° to 60°. Therefore, in this embodiment, noise at a frequency of 4000Hz can be reduced within the range of 30° to 60°. As described above, in this embodiment, the angle β of corner 372c is 40° to 60°, therefore, the blower 310, by providing the reflector 370, can reduce noise at a frequency of 4000Hz.

[0098] Figure 12 The second figure shows the primary noise Nw of the blades of the blower 310 in this embodiment. Figure 12 The horizontal axis is the angle β of the corner 372c. Figure 12 The vertical axis represents the primary noise Nw of the blade. For example... Figure 12 As shown, the primary blade noise Nw decreases as the angle β of corner 372c increases within the range of 30° to 45°, and increases as the angle β of corner 372c increases within the range of 45° to 60°. The primary blade noise Nw within the range of 40° to 60° angle β of corner 372c is less than the primary blade noise Nw when the angle β of corner 372c is 30°. As described above, in this embodiment, the angle β of corner 372c is 40° to 60°. Therefore, in this embodiment, compared to the case where the angle β of corner 372c is 30°, the increase in primary blade noise Nw can be suppressed. As described above, in this embodiment, the angle β of corner 372c is 40° to 60°, thus noise at a frequency of 4000Hz can be reduced. Therefore, in this embodiment, the angle β of the corner 372c is 40° or more and 60° or less, which can suppress the increase of the primary noise Nw of the blade and reduce the noise at a frequency of 4000 Hz.

[0099] In this embodiment, in order to increase the noise reduction Nd and reduce the primary noise Nw of the blade, the angle β of the corner 372c is preferably 40° or more and 60° or less, more preferably 45° or more and 50° or less, and even more preferably 45°.

[0100] Figure 13 The third figure shows the noise reduction Nd of the blower 310 in this embodiment. Figure 13 The horizontal axis represents the size ratio Rs. Figure 13 The vertical axis represents the noise reduction Nd. For example... Figure 13 As shown, the noise reduction Nd increases with increasing size ratio Rs within the range of 37.5% to 50.0%, and decreases with increasing size ratio Rs within the range of 50.0% to 62.5%. The noise reduction Nd is positive within the range of 37.5% to 62.5%. Therefore, in this embodiment, noise at a frequency of 4000Hz can be reduced within the range of size ratio Rs of 37.5% to 62.5%. As described above, in this embodiment, the size ratio Rs is 37.5% to 55.0%, therefore, the blower 310, by providing the reflector 370, can reduce noise at a frequency of 4000Hz.

[0101] Figure 14 The third figure shows the primary noise Nw of the blades of the blower 310 in this embodiment. Figure 14 The horizontal axis represents the size ratio Rs. Figure 14 The vertical axis represents the primary noise Nw of the blade. For example... Figure 14 As shown, the primary blade noise Nw is approximately the same in the range where the size ratio Rs is 37.5% or higher and 50.0% or lower, and increases as the size ratio Rs increases in the range where the size ratio Rs is 50.0% or higher and 62.5% or lower. The primary blade noise Nw in the range where the size ratio Rs is 37.5% or higher and 55.0% or lower is less than the primary blade noise Nw when the size ratio Rs is 62.5%. As described above, in this embodiment, the size ratio Rs is 37.5% or higher and 55.0% or lower. Therefore, in this embodiment, the increase in primary blade noise Nw can be suppressed compared to the case where the size ratio Rs is 62.5%. As described above, in this embodiment, the size ratio Rs is 37.5% or higher and 55.0% or lower, thus noise at a frequency of 4000 Hz can be reduced. Therefore, in this embodiment, the size ratio Rs is 37.5% or more and 55.0% or less, which can suppress the increase of primary blade noise Nw and reduce noise at a frequency of 4000 Hz.

[0102] In this embodiment, in order to increase the noise reduction Nd and reduce the primary noise Nw of the blade, the size ratio Rs is preferably 40.0% or more and 60.0% or less, more preferably 45.0% or more and 55.0% or less, and even more preferably 50.0%.

[0103] According to this embodiment, when viewed from the axial direction, the angle α formed by the first imaginary straight line V1 passing through the first end 370a (the end on the circumferential side, +θ side) of the reflector 370 and the central axis J, and the second imaginary straight line V2 passing through the second end 370c (the end on the other circumferential side, -θ side) of the reflector 370 and the central axis J, i.e., the central angle α, is 15° or more and 30° or less. Therefore, as described above, in this embodiment, the increase in primary blade noise Nw can be suppressed, and noise at a frequency of 4000Hz can be reduced. Therefore, the noise of the blower 310 can be appropriately suppressed.

[0104] Furthermore, in this embodiment, the center angle α is 30° or less, thus preventing the circumferential length of the reflector 370 from becoming too long. This prevents the length of the air flowing in the air supply path 40a from interfering with the reflector 370 from becoming too long. Therefore, the reduction in the air volume delivered from the exhaust port 40b to the outside of the blower 310 can be appropriately suppressed.

[0105] According to this embodiment, the reflector 370 has a protrusion 372 whose axial dimension increases as it moves from the end on the other circumferential side (-θ side) towards the circumferential side (+θ side) of the reflector 370. When viewed radially, the angle β of the corner 372c of the end on the other circumferential side of the protrusion 372 is 40° or more and 60° or less. Therefore, as described above, in this embodiment, the increase in primary blade noise Nw can be suppressed, and noise at a frequency of 4000 Hz can be reduced.

[0106] Furthermore, in this embodiment, the angle β of the corner 372c can be prevented from becoming too large, thus making it easier for the orientation of the top surface 372a to approach a direction orthogonal to the circumferential direction. As a result, the air flowing in the air supply path 40a easily flows circumferentially along the top surface 372a, thus easily suppressing interference between the air flowing in the air supply path 40a and the top surface 372a. Therefore, the reduction in the air volume delivered from the exhaust port 40b to the outside of the blower 310 can be more appropriately suppressed.

[0107] According to this embodiment, the size ratio Rs, i.e., the ratio of the maximum axial dimension Lr of the reflector 370 to the axial dimension Li of the inner surface 350, is 37.5% or more and 55.0% or less. Therefore, as described above, in this embodiment, the increase in primary blade noise Nw can be suppressed, and noise at a frequency of 4000 Hz can be reduced.

[0108] Furthermore, in this embodiment, the size ratio Rs is 55.0% or less, thus preventing the maximum axial dimension Lr of the reflector 370 from becoming too large. This allows for more appropriate suppression of interference between the air flowing in the air supply path 40a and the reflector 370. Consequently, it also allows for more appropriate suppression of the reduction in airflow volume delivered from the exhaust port 40b to the outside of the blower 310.

[0109] The above description describes one embodiment of the present invention. However, the various components and combinations thereof in the embodiment are merely examples, and additions, omissions, substitutions, and other modifications can be made to the configuration without departing from the spirit of the present invention. Furthermore, the present invention is not limited to the embodiments described above. For example, the application of the blower shown in the above embodiments is not particularly limited.

[0110] The configuration of the inner surface is not limited to this embodiment. For example, when viewed from the axial direction, the inner surface may also be a curved shape in which the radial distance between it and the central axis increases as it moves toward the other side of the circumference. Furthermore, the inner surface may not have a straight portion.

[0111] Furthermore, the radial distance between the reflector and the inner surface can increase as it moves toward one side of the circumference, or it can increase as it moves toward the other side of the circumference. Similarly, the radial distance between the reflector and the impeller portion can increase as it moves toward one side of the circumference, or it can increase as it moves toward the other side of the circumference.

[0112] It should be noted that this technology can have the following configuration.

[0113] (1) A blower comprising: a motor having a rotor that rotates about a central axis; an impeller that rotates together with the rotor; a housing that internally accommodates the impeller; and a reflector disposed radially between the impeller and an inner side of the housing and extending circumferentially, a portion of the inner side being radially opposed to the impeller and another portion of the inner side being radially opposed to the reflector.

[0114] (2) The blower according to (1), wherein the housing has: a top plate portion disposed on an axial side relative to the impeller portion; and a bottom plate portion disposed on an axial side relative to the impeller portion, wherein the reflector protrudes axially from one of the top plate portion or the bottom plate portion and is axially spaced apart from the other of the top plate portion or the bottom plate portion.

[0115] (3) The blower according to (2), wherein the top plate has an air inlet that extends through the top plate in an axial direction, and the reflector protrudes from the top plate to the other side in an axial direction and is axially spaced apart from the bottom plate.

[0116] (4) The blower according to (2), wherein the top plate has an air inlet that extends through the top plate in an axial direction, and the reflector protrudes from the bottom plate to one side in an axial direction and is axially spaced from the top plate.

[0117] (5) The blower according to any one of (1) to (4), wherein, when viewed from the axial direction, the inner surface is curved and the radial distance between it and the central axis increases as it tends toward the circumferential side, and at least a portion of the reflector extends circumferentially at a certain interval from the inner surface in the radial direction.

[0118] (6) The blower according to any one of (1) to (4), wherein, when viewed from the axial direction, the inner surface is curved and the radial distance between it and the central axis increases as it tends toward the circumferential side, and at least a portion of the reflector extends circumferentially at a certain interval from the impeller portion in the radial direction.

[0119] (7) The blower according to any one of (1) to (6), wherein the housing has an exhaust port for discharging air to the outside, the inner side has a straight portion connected to the exhaust port and extending in a straight line when viewed from the axial direction, and a portion of the reflector overlaps with the straight portion when viewed from the radial direction.

[0120] (8) The blower according to any one of (1) to (7), wherein, when viewed from the axial direction, the angle between a first imaginary straight line passing through the end of the reflector on one circumferential side and the central axis and a second imaginary straight line passing through the end of the reflector on the other circumferential side and the central axis is more than 15° and less than 30°.

[0121] (9) The blower according to any one of (1) to (8), wherein the reflector has a protrusion whose axial dimension increases as it moves from one end of the reflector to the other side of the circumference toward the other side, and the angle of the corner of the end of the reflector on the other side of the circumference, when viewed radially, is more than 40° and less than 60°.

[0122] (10) The blower according to any one of (1) to (9), wherein the ratio of the maximum axial dimension of the reflector to the axial dimension of the inner side surface is more than 40.0% and less than 60.0%.

Claims

1. A blower, said blower comprising: The motor unit has a rotor that rotates about a central axis; An impeller section that can rotate together with the rotor; A housing that internally accommodates the impeller portion; and A reflector, which is radially disposed between the impeller portion and the inner side of the housing, and extends circumferentially. A portion of the inner side faces the impeller in the radial direction, and another portion of the inner side faces the reflector in the radial direction.

2. The blower according to claim 1, wherein, The housing includes: a top plate portion disposed axially relative to the impeller portion; and a bottom plate portion disposed axially relative to the impeller portion. The reflector protrudes axially from one of the top plate portion or the bottom plate portion and is axially spaced apart from the other of the top plate portion or the bottom plate portion.

3. The blower according to claim 2, wherein, The top plate has an air inlet that extends axially through the top plate. The reflector protrudes from the top plate portion to the other side axially and is axially spaced apart from the bottom plate portion.

4. The blower according to claim 2, wherein, The top plate has an air inlet that extends axially through the top plate. The reflector protrudes from the bottom plate portion to one axial direction and is axially spaced from the top plate portion.

5. The blower according to any one of claims 1 to 4, wherein, When viewed from the axial direction, the inner surface is a curve whose radial distance from the central axis increases as it moves toward the circumferential side. At least a portion of the reflector extends circumferentially at a radially spaced interval from the inner surface.

6. The blower according to any one of claims 1 to 4, wherein, When viewed from the axial direction, the inner surface is a curve whose radial distance from the central axis increases as it moves toward the circumferential side. At least a portion of the reflector extends circumferentially at a certain interval in the radial direction from the impeller portion.

7. The blower according to any one of claims 1 to 4, wherein, The housing has an exhaust port for discharging air to the outside. The inner surface has a straight portion that is connected to the exhaust port and extends in a straight line when viewed from the axial direction. When viewed radially, a portion of the reflector overlaps with the straight portion.

8. The blower according to any one of claims 1 to 4, wherein, When viewed from the axial direction, the angle between a first imaginary line passing through the end of the reflector on one circumferential side and the central axis and a second imaginary line passing through the end of the reflector on the other circumferential side and the central axis is more than 15° and less than 30°.

9. The blower according to any one of claims 1 to 4, wherein, The reflector has a protrusion whose axial dimension increases as it moves from one end of the reflector to the other side of the circumference. When viewed radially, the angle of the corner of the end portion including the protrusion on the other side of the circumference is 40° or more and 60° or less.

10. The blower according to any one of claims 1 to 4, wherein, The ratio of the maximum axial dimension of the reflector to the axial dimension of the inner side surface is more than 40.0% and less than 60.0%.

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