blower

Abstract

A blower includes a motor, a closed impeller that is rotated by the motor and is a turbofan, and a fan case that accommodates the closed impeller, wherein the fan case includes a scroll portion that surrounds the closed impeller and a duct portion that extends from the scroll portion, the scroll portion includes a suction port through which a rotation axis of the motor passes and through which a gas is sucked, the duct portion includes a discharge port that discharges the gas, and an inner peripheral edge of the suction port includes an arc-shaped edge that extends in an arc shape around the rotation axis and a straight edge that continuously extends from the arc-shaped edge in a straight line shape when viewed in a direction along the rotation axis.

Description

Technical Field

[0001] This invention relates to a blower. Background Technology

[0002] Blowers with reduced noise are known (see, for example, Patent Document 1).

[0003] [Existing Technical Documents]

[0004] [Patent Literature]

[0005] [Patent Document 1] Japanese Unexamined Patent Application Publication No. H07-91392 Summary of the Invention

[0006] The problem to be solved by the present invention

[0007] Some blowers include a fan casing that houses a closed impeller that functions as a turbine fan. In such blowers, noise suppression is also desirable.

[0008] Therefore, the object of the present invention is to provide a blower with reduced noise.

[0009] Technical means to solve the problem

[0010] The above objective is achieved by a blower comprising: a motor; a closed impeller that is rotated by the motor and is a turbofan; and a fan housing that houses the closed impeller, wherein the fan housing includes: a vortex portion surrounding the closed impeller; and a duct portion extending from the vortex portion, the vortex portion including a suction port through which the rotation axis of the motor passes and through which gas is drawn, the duct portion including a discharge port for discharging gas, and the inner peripheral edge of the suction port including: an arcuate edge extending in an arcuate shape around the rotation axis; and a straight edge extending continuously from the arcuate edge in a straight line shape when viewed in the direction of the rotation axis.

[0011] Effects of the present invention

[0012] According to the present invention, a blower with reduced noise can be provided. Attached Figure Description

[0013] Figure 1 This is an explanatory diagram of a comparative example blower;

[0014] Figure 2A and Figure 2B Here is an explanatory diagram of a comparative example blower:

[0015] Figure 3 This is an explanatory diagram of a comparative example blower;

[0016] Figure 4 It is an external three-dimensional view of a closed impeller;

[0017] Figure 5A It is along Figure 2B The cross-sectional view taken from line BB in the middle, and Figure 5B It is along Figure 2B A cross-sectional view taken from line CC in the diagram;

[0018] Figure 6A This is an explanatory diagram of the suction port of a comparative example blower, and Figure 6B This is an illustration of the airflow in the upper casing of a comparative example blower;

[0019] Figure 7A This is an explanatory diagram of the suction port of the blower according to the first embodiment, and Figure 7B This is an explanatory diagram of the airflow in the upper casing of the blower according to the first embodiment;

[0020] Figure 8A and Figure 8B This is a diagram showing a blower of a first embodiment with different angular positions of the suction port;

[0021] Figure 9A This is an explanatory diagram of the suction port of the blower in the second embodiment, and Figure 9B This is an explanatory diagram of the airflow in the upper casing of the blower according to the second embodiment;

[0022] Figure 10A and Figure 10B This is a diagram showing a blower of a second embodiment with different angular positions of the suction port;

[0023] Figure 11A This is an explanatory diagram of the suction port of the blower in the third embodiment, and Figure 11B This is an explanatory diagram of the airflow in the upper casing of the blower according to the third embodiment;

[0024] Figure 12A and Figure 12B This is a diagram showing a blower according to a third embodiment with different angular positions of the suction port; and

[0025] Figure 13 This is a table showing the measurement results of noise. Detailed Implementation

[0026] [Comparative Example]

[0027] Before describing the blower of this embodiment, the blower of the comparative example 1x will be described. Figure 1 , Figure 2A, Figure 2B and Figure 3 This is an explanatory diagram of the comparative example blower 1x. Figure 1 This is a three-dimensional view of the comparative example blower 1x. Figure 2A This is a top view of the comparative example blower 1x. Figure 2B This is a side view of the comparative example blower 1x. Figure 3 It is along Figure 2A The cross-sectional view taken from line AA in the diagram.

[0028] The blower 1x includes a motor 10, a closed impeller 30, a bearing retainer 40, a motor housing 50, a cable retainer 55, and a fan housing 70. Figure 1 Other figures show the rotation axis A of motor 10 and the pipe axis B of pipe section 75, which will be described later. Motor 10 is housed in motor housing 50. Closed impeller 30 is housed in fan housing 70. Closed impeller 30 is a turbofan. Cable retainer 55 is attached to motor housing 50 and holds multiple cables C.

[0029] The fan housing 70 includes an upper housing 71 and a lower housing 72 assembled together. The fan housing 70 includes a vortex portion 73 and a duct portion 75. A suction port 74 for drawing gas into the fan housing 70 is formed at the center above the vortex portion 73, in other words, at the center of the upper housing 71. A rotation axis A passes through the suction port 74.

[0030] The pipe section 75 extends from the vortex section 73 along the pipe axis B. The pipe axis B does not intersect the rotation axis A. The direction in which the pipe axis B extends is perpendicular to the direction in which the rotation axis A extends. The pipe axis B extends tangentially in a circle centered on the rotation axis A and in a plane perpendicular to the rotation axis A. A discharge port 76 is formed at the end of the pipe section 75. The vortex section 73 has a constant-width vortex flow channel P extending substantially annularly around the rotation axis A, which will be described in detail later. Gas introduced into the constant-width vortex flow channel P via the suction port 74 is discharged from the discharge port 76 of the pipe section 75. Figure 2A The area S4 of the suction port 74 shown is greater than Figure 2B The area S6 of the emission port 76 shown.

[0031] The bearing retaining member 40 includes a cylindrical portion 41 and a flange portion 42. The cylindrical portion 41 and the flange portion 42 face the lower surface of the closed impeller 30. The cylindrical portion 41 has a substantially cylindrical shape. Two bearings 48 are retained inside the cylindrical portion 41 to rotatably support the rotating shaft 13. The two bearings 48 support approximately the central portion of the rotating shaft 13. The flange portion 42 is fixed to the upper end of the cylindrical portion 41. A collar 44 is fixed to the outer peripheral portion of the cylindrical portion 41. A vibration damping member 45 is disposed between the collar 44 and the lower housing 72. A nut 46 is threaded onto the outer peripheral surface of the cylindrical portion 41. The collar 44 and the vibration damping member 45 are retained between the nut 46 and the flange portion 42. The vibration damping member 45 separates the space accommodating the closed impeller 30 from the space accommodating the motor 10.

[0032] Motor 10 includes a rotor 11, coil 16, insulator 17, stator 18, and printed circuit board 19. Rotor 11 includes a rotating shaft 13, yoke 14, and magnet 15. The rotation axis A of motor 10 passes through the center of rotating shaft 13 and is parallel to rotating shaft 13. A closed impeller 30 is fixed to the end of rotating shaft 13. Yoke 14 is fixed to the proximal end of rotating shaft 13. Magnet 15 is held on the outer periphery of yoke 14. Magnet 15 has a cylindrical shape and is magnetized with different polarities in the circumferential direction. Rotating shaft 13, yoke 14, and magnet 15 rotate integrally.

[0033] The stator 18 is disposed radially outside the magnet 15. Each of a plurality of coils 16 is wound around the stator 18 via an insulator 17. The plurality of coils 16 are electrically connected to a printed circuit board 19. A plurality of cables C are connected to the printed circuit board 19. Electronic circuitry disposed outside the motor 10 and the printed circuit board 19 is electrically connected to each other via the plurality of cables C, thereby controlling the energization of the plurality of coils 16. When the plurality of coils 16 are energized, a magnetic force is generated between the stator 18 and the magnet 15. Therefore, the closed impeller 30 rotates together with the rotor 11.

[0034] Figure 4 This is an external perspective view of the closed impeller 30. The closed impeller 30 includes a hub 31, blades 33, and a shroud 35. The hub 31 is generally disc-shaped. The blades 33 are arranged on the hub 31 at regular intervals in the circumferential direction. The shroud 35 is also generally disc-shaped. The shroud 35 is fixed to the upper portion of the plurality of blades 33 and faces the hub 31, with a predetermined gap between the shroud 35 and the hub 31. An opening 352 is formed at the center of the shroud 35. Gas introduced into the fan housing 70 through the suction port 74 flows radially outward through the opening 352, through the gap between the blades 33 between the hub 31 and the shroud 35, and flows in a constant-width vortex flow channel P. A shaft hole 312 is formed at the center of the hub 31.

[0035] The outer peripheral edge 311 of the hub 31 is located radially outside the outer peripheral edge 351 of the cover 35. That is, the diameter of the hub 31 is larger than the diameter of the cover 35, but the present invention is not limited thereto. For example, the diameter of the hub 31 and the diameter of the cover 35 can be substantially the same.

[0036] Next, we will refer to Figure 3 , Figure 5A and Figure 5B Describe a constant-width vortex flow channel P. Figure 5A It is along Figure 2B The cross-sectional view taken from line BB in the diagram. Figure 5B It is along Figure 2B The cross-sectional view taken by line CC in the diagram. For example... Figure 3 As shown, the constant-width vortex flow channel P is defined by the inner surface 711 of the upper housing 71 and the inner surface 721 of the lower housing 72. The upper portion of the inner surface 711... Figure 3 The cross-sectional view shows it to be curved and extends in a substantially annular shape around the axis of rotation A. The lower portion of the inner surface 721 is... Figure 3 In its cross-sectional view, it is curved and extends in a substantially annular shape around the axis of rotation A. Inner surfaces 711 and 721 face each other in a direction parallel to the axis of rotation A.

[0037] like Figure 3 and Figure 5A As shown, the inner surface 711 has an outer peripheral surface 712. The inner surface 721 has an outer peripheral surface 722 and an inner peripheral surface 723 that are opposite to each other in the radial direction. Figure 5A As shown, the radial distance between the outer peripheral surface 722 and the inner peripheral surface 723 is constant in the circumferential direction. That is, the width W1 of the constant-width vortex flow channel P is constant in the circumferential direction around the rotation axis A.

[0038] like Figure 5B As shown, the radial distance between the outer peripheral edge 311 of the hub 31 of the closed impeller 30 and the outer peripheral surface 712 of the upper housing 71 is constant in the circumferential direction. Therefore, the width W2 between the outer peripheral edge 311 of the hub 31 and the outer peripheral surface 712 of the upper housing 71 is constant in the circumferential direction. Furthermore, unlike the constant-width vortex flow channel P in this embodiment, a widened vortex flow path with a width that gradually increases circumferentially toward the discharge port is known. The widened vortex flow channel has higher fan efficiency than the constant-width vortex flow channel, but tends to generate more noise.

[0039] Figure 6A This is an explanatory diagram of the suction port 74 of the comparative example blower 1x. Figure 6BThis is an explanatory diagram of the airflow F1 and F2 in the upper housing 71 of the comparative example blower 1x. When viewed along a direction parallel to the axis of rotation A, the inner peripheral edge of the suction port 74 has a circular shape. Figure 6B As shown, the upper housing 71 has a facing surface 715 facing the shroud 35 of the closed impeller 30, and there is a predetermined gap between the facing surface 715 and the shroud 35.

[0040] like Figure 6B As shown, when the closed impeller 30 rotates, airflow F1 passes through the closed impeller 30 from the suction port 74 via the opening 352 and flows into the constant-width vortex flow channel P. Airflow F2 flows rearward from the gap between the outer peripheral edge 351 of the shroud 35 and the inner surface of the upper housing 71 between the shroud 35 and the facing surface 715, and flows into the opening 352. Therefore, airflows F1 and F2 flowing in different directions collide with each other near the opening 352, producing a collision sound. It is assumed that this collision between airflows F1 and F2 occurs over the entire circumference of the opening 352. Because the opening 352 is close to the suction port 74, the noise generated by this collision is relatively large in the comparative example blower 1x.

[0041] [First Implementation Method]

[0042] Next, the blower 1a of the first embodiment will be described. The suction port 74a of the blower 1a in the first embodiment has a different shape than the suction port 74 of the blower 1x in the comparative example. The other configurations of the blower 1a and the blower 1x are the same. Figure 7A This is an explanatory diagram of the suction port 74a of the blower 1a in the first embodiment. Figure 7B This is an explanatory diagram of the airflow F3 and F4 in the upper housing 71a of the blower according to the first embodiment.

[0043] like Figure 7A As shown, the inner peripheral edge of the suction port 74a includes a single arcuate edge 74a1 and a single straight edge 74a2. When viewed in the direction of the rotation axis A, the arcuate edge 74a1 extends in an arcuate shape around the rotation axis A. The radius of the arcuate edge 74a1 is the same as the radius of the suction port 74 in the comparative example. The length of the arcuate edge 74a1 is greater than the semicircular circumference of the suction port 74 in the comparative example. The straight edge 74a2 is continuous with the arcuate edge 74a1 and extends linearly when viewed in the direction of the rotation axis A. The straight edge 74a2 is located within the suction port 74 of the comparative example but is separated from the rotation axis A. The length of the straight edge 74a2 is shorter than the diameter of the suction port 74 in the comparative example. The arcuate edge 74a1 and the straight edge 74a2 are smoothly curved and continuous with each other. The area of ​​the suction port 74a is smaller than the area S4 of the suction port 74 in the comparative example, but larger than the area S6 of the discharge port 76.

[0044] like Figure 7B As shown, airflow F3 passes through the closed impeller 30 via opening 352 along the straight edge 74a2 of the suction port 74a and flows into the constant-width vortex flow channel P. Airflow F4 flows rearward from the gap between the outer peripheral edge 351 of the shroud 35 and the inner surface of the upper housing 71 between the shroud 35 and the facing surface 715, and flows into opening 352. Here, similar to the blower 1x of the comparative example, airflows F3 and F4 flowing in different directions collide with each other near opening 352. However, as Figure 6B As shown, airflow F2 collides with airflow F1 flowing along suction port 74 near opening 352. On the other hand, as... Figure 7B As shown, after flowing through the opening 352 between the hub 31 and the shroud 35, the airflow F4 collides with the airflow F3 flowing along the straight edge 74a2. Therefore, when the airflow F4 collides with the airflow F3, the direction of the airflow F4 is substantially along the direction of the airflow F3, and the collision noise is suppressed. Therefore, compared with the blower 1x of the comparative example, the noise of the blower 1a of the first embodiment is suppressed.

[0045] Figure 8A and Figure 8B This is a diagram of a blower 1a according to a first embodiment, with different angular positions of the suction port 74a. Reference line L1 extends from the rotation axis A toward the side of the pipe portion 75 protruding from the vortex portion 73, and is parallel to the pipe axis B. Angle line L2 extends radially outward from the rotation axis A and is orthogonal to the straight edge 74a2. Figure 8A In blower 1a, the angle from reference line L1 to angle line L2 in the counterclockwise direction is set to 110 degrees. Figure 8B In the blower 1a, the aforementioned angle is set to 155 degrees. This allows the angular position of the suction port 74a to be changed according to various conditions.

[0046] [Second Implementation]

[0047] Figure 9A This is an explanatory diagram of the suction port 74b of the blower 1b in the second embodiment. Figure 9B This is an explanatory diagram of the airflow F3 and F4 in the upper housing 71b of the blower 1b according to the second embodiment. Figure 9AAs shown, the inner peripheral edge of the suction port 74b includes two arcuate edges 74b1 and two straight edges 74b2. When viewed in the direction of the rotation axis A, the arcuate edges 74b1 extend in an arcuate shape around the rotation axis A. The radius of the arcuate edges 74b1 is the same as the radius of the suction port 74 in the comparative example. The straight edges 74b2 are continuous with the arcuate edges 74b1 and extend linearly when viewed in the direction of the rotation axis A. The two arcuate edges 74b1 are symmetrical about the rotation axis A. The two straight edges 74b2 are symmetrical about the rotation axis A. Therefore, the suction port 74b is symmetrical about the rotation axis A. The area of ​​the suction port 74b is smaller than the area S4 of the suction port 74 in the comparative example and the area of ​​the suction port 74a in the first embodiment, but larger than the area S6 of the discharge port 76.

[0048] like Figure 9B As shown, after the airflow F4 flows through the opening 352 between the hub 31 and the shroud 35, it collides with the airflow F3 flowing along the straight edge 74b2 of the suction port 74b. Therefore, when the airflow F4 collides with the airflow F3, the direction of the airflow F4 is substantially along the direction of the airflow F3, and the collision noise is suppressed. Therefore, compared with the blower 1x of the comparative example, the noise of the blower 1b of the second embodiment is suppressed.

[0049] Figure 10A and Figure 10B This is a diagram of a blower 1b in a second embodiment with a different angular position of the suction port 74b. Angle line L2 extends radially outward from the rotation axis A and is perpendicular to one of the two straight edges 74b2. Figure 10A In blower 1b, the angle is set to 315 degrees. Figure 10B In the blower 1b, the angle is set to 45 degrees. In this way, the angular position of the suction port 74b can be changed according to various conditions.

[0050] [Third Implementation Method]

[0051] Figure 11A This is an explanatory diagram of the suction port 74c of the blower 1c in the third embodiment. Figure 11B This is an explanatory diagram of the airflow F3 and F4 in the upper housing 71c of the blower 1c according to the third embodiment. Figure 11AAs shown, the inner peripheral edge of the suction port 74c includes three arcuate edges 74c1 and three straight edges 74c2. When viewed in the direction of the rotation axis A, the arcuate edges 74c1 extend in an arcuate shape around the rotation axis A. The radius of the arcuate edges 74c1 is the same as the radius of the suction port 74 of the comparative example. The straight edges 74c2 are continuous with the arcuate edges 74c1 and extend linearly when viewed in the direction of the rotation axis A. The three arcuate edges 74c1 are symmetrical about the rotation axis A. The three straight edges 74c2 are symmetrical about the rotation axis A. Therefore, the suction port 74c is symmetrical about the rotation axis A. The area of ​​the suction port 74c is smaller than the area S4 of the suction port 74 of the comparative example, the area of ​​the suction port 74a of the first embodiment, and the area of ​​the suction port 74b of the second embodiment, but larger than the area S6 of the discharge port 76.

[0052] like Figure 11B As shown, after flowing through the opening 352 between the hub 31 and the shroud 35, the airflow F4 collides with the airflow F3 flowing along the straight edge 74c2 of the suction port 74c. Therefore, when the airflow F4 collides with the airflow F3, the direction of the airflow F4 is substantially along the direction of the airflow F3, and the collision noise is suppressed. Therefore, compared with the blower 1x of the comparative example, the noise of the blower 1c of the third embodiment is suppressed.

[0053] Figure 12A and Figure 12B This is a diagram of a blower 1c in a third embodiment with different angular positions of the suction port 74c. Angle line L2 extends radially outward from the rotation axis A and is orthogonal to one of the three straight edges 74c2. Figure 12A In blower 1c, the angle is set to 45 degrees. Figure 12B In the blower 1c, the angle is set to 75 degrees. In this way, the angular position of the suction port 74c can be changed according to various conditions.

[0054] [Measurement Results]

[0055] Next, the noise measurement results of the comparative example blower 1x, the blower 1a of the first embodiment, the blower 1b of the second embodiment, and the blower 1c of the third embodiment will be described. The rotational speed of the closed impeller 30 was kept constant, and the opening of the throttle valve (not shown) attached to the discharge port 76 of the duct section 75 for measurement was changed to alter the flow rate of the air discharged from the discharge port 76 to 190 L / min, 220 L / min, and 240 L / min, and the noise was measured at each flow rate. Furthermore, noise was measured in blowers at different angles between the reference line L1 and the angle line L2 at the corresponding flow rates. In the blower 1a of the first embodiment, noise was measured at the aforementioned angles of 20 degrees, 65 degrees, 110 degrees, 155 degrees, 200 degrees, 245 degrees, 290 degrees, and 335 degrees. In the blower 1b of the second embodiment, noise was measured at angles of 315 degrees, 0 degrees, 45 degrees, and 90 degrees. In the blower 1c of the third embodiment, noise was measured at angles of 15 degrees, 45 degrees, 75 degrees, and 105 degrees. Figure 13 This is a table showing the measurement results of noise.

[0056] When the flow rate is 190 L / min, the flow rate of the comparative example blower 1x is 83.35 dB(A). In the blower 1a of the first embodiment, the noise is reduced more than that of the comparative example blower 1x in substantially the entire region of the aforementioned angle. In particular, the noise reduction is significant at the aforementioned angles of 20 degrees, 65 degrees, 110 degrees, and 155 degrees.

[0057] When the flow rate is 220 L / min, the flow rate of the comparative example blower 1x is 88.12 dB(A). In the blower 1a of the first embodiment, the noise is reduced more than that of the comparative example blower 1x in substantially the entire region of the aforementioned angle. In particular, the noise reduction is significant when the aforementioned angles are 20 degrees, 65 degrees, 110 degrees, 155 degrees, and 335 degrees.

[0058] When the flow rate is 245 L / min, the flow rate of the comparative example blower 1x is 91.40 dB(A). In the blower 1a of the first embodiment, the noise is reduced more than that of the comparative example blower 1x in substantially the entire region of the aforementioned angle.

[0059] Therefore, in the blower 1a of the first embodiment, by setting the aforementioned angle within the range of 20 degrees to 155 degrees and 335 degrees to 20 degrees, noise is suppressed regardless of the flow rate. In particular, in the blower 1a of the first embodiment, noise is sufficiently suppressed by setting the aforementioned angle within the range of 110 degrees to 155 degrees.

[0060] In the blower 1b of the second embodiment, the noise is reduced more than that of the blower 1x of the comparative example, regardless of the flow rate, over substantially the entire range of the aforementioned angle. In particular, in the blower 1b of the second embodiment, noise is sufficiently suppressed by setting the aforementioned angle within the range of 315 degrees to 45 degrees.

[0061] In the blower 1c of the third embodiment, the noise is reduced more than that of the blower 1x of the comparative example, regardless of the flow rate, over substantially the entire range of the aforementioned angle. In particular, in the blower 1c of the third embodiment, noise is sufficiently suppressed by setting the aforementioned angle within the range of 45 degrees to 75 degrees.

[0062] Although exemplary embodiments of the present invention have been described in detail, the present invention is not limited to the above embodiments, and other embodiments, variations and modifications can be made without departing from the scope of the present invention.

Claims

1. A blower, the blower comprising: motor; A closed impeller, which is rotated by the motor and is a turbofan; as well as Fan housing, the fan housing housing the closed impeller, in, The fan housing includes: A vortex portion surrounding the closed impeller; and The pipe section extends from the vortex section. The vortex section includes a suction port through which the rotation axis of the motor passes and through which gas is drawn. The pipeline section includes an exhaust port for discharging gas, and The inner peripheral edge of the suction port includes: Arc-shaped edge, the arc-shaped edge extending in an arc shape around the axis of rotation; and A straight edge, when viewed in the direction of the axis of rotation, extends continuously from the arcuate edge in a straight line shape.

2. The blower according to claim 1, wherein, The arcuate edge included in the inner peripheral edge of the suction port is a single one, and the straight edge included in the inner peripheral edge of the suction port is a single one.

3. The blower according to claim 1, wherein, The inner peripheral edge of the suction port includes: The two arcuate edges symmetrical about the axis of rotation in the arcuate edge; and The two straight edges that are symmetrical about the axis of rotation are among the straight edges.

4. The blower according to claim 1, wherein, The inner peripheral edge of the suction port includes: The three arcuate edges symmetrical about the axis of rotation in the arcuate edge; and The three straight edges that are symmetrical about the axis of rotation are among the straight edges.

5. The blower according to any one of claims 1 to 4, wherein, The vortex portion includes a constant-width vortex flow channel that is connected to the suction port and has a constant width in the circumferential direction around the axis of rotation.

6. The blower according to any one of claims 1 to 4, wherein, The area of ​​the suction port is larger than the area of ​​the discharge port.

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