Blower

Abstract

The objective is to provide a blower with reduced noise. [Solution] A blower comprising a motor, a closed impeller which is a turbo fan and is rotated by the motor, and a fan case which houses the closed impeller, wherein the fan case includes a scroll section which surrounds the closed impeller and a duct section which extends from the scroll section, the scroll section which has an intake port through which the rotation axis of the motor passes and draws in gas, the duct section which has an outlet which discharges gas, and the inner peripheral edge of the intake port which, when viewed from the direction of the rotation axis, includes an arc edge which extends in an arc shape centered on the rotation axis and a straight edge which extends in a straight line continuous with the arc edge.

Description

Technical Field

[0007] ,

[0001] The present invention relates to a blower.

Background Art

[0002] A blower with suppressed noise is known (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003] <​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​ We can provide blowers with reduced noise. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is an explanatory diagram of a comparative example blower. [Figure 2] Figures 2A and 2B are explanatory diagrams of a comparative example blower. [Figure 3] Figure 3 is an explanatory diagram of a comparative example blower. [Figure 4] Figure 4 is a perspective view of the closed impeller. [Figure 5] Figure 5A is a cross-sectional view of BB in Figure 2B, and Figure 5B is a cross-sectional view of CC in Figure 2B. [Figure 6] Figure 6A is an explanatory diagram of the intake port of the comparative example blower, and Figure 6B is an explanatory diagram of the airflow inside the upper case of the comparative example blower. [Figure 7] Figure 7A is an explanatory diagram of the intake port of the blower in the first embodiment, and Figure 7B is an explanatory diagram of the airflow inside the upper case of the blower in the first embodiment. [Figure 8] Figures 8A and 8B are illustrative diagrams of a blower according to the first embodiment, showing different angle positions of the intake port. [Figure 9] Figure 9A is an explanatory diagram of the intake port of the blower in the second embodiment, and Figure 9B is an explanatory diagram of the airflow inside the upper case of the blower in the second embodiment. [Figure 10] Figures 10A and 10B are illustrative diagrams of a second embodiment of a blower with a different angle position of the intake port. [Figure 11] Figure 11A is an explanatory diagram of the intake port of the blower in the third embodiment, and Figure 11B is an explanatory diagram of the airflow inside the upper case of the blower in the third embodiment. [Figure 12] Figures 12A and 12B are illustrative diagrams of a third embodiment of a blower with a different angle position of the intake port. [Figure 13] Figure 13 is a table showing the noise measurement results. [Modes for carrying out the invention]

[0009] [Comparative Example] Before describing the blower of this embodiment, we will describe the comparative example blower 1x. Figures 1, 2A, 2B, and 3 are explanatory diagrams of the comparative example blower 1x. Figure 1 is a perspective view of the comparative example blower 1x. Figure 2A is a top view of the comparative example blower 1x. Figure 2B is a side view of the comparative example blower 1x. Figure 3 is a cross-sectional view of Figure 2A, section AA.

[0010] The blower 1x includes a motor 10, a closed impeller 30, a bearing retaining member 40, a motor case 50, a cable holder 55, and a fan case 70. Figure 1 shows the rotation axis A of the motor 10 and the duct axis B of the duct section 75, which will be described later. The motor 10 is housed in the motor case 50. The closed impeller 30 is housed in the fan case 70. The closed impeller 30 is a turbo fan. The cable holder 55 is attached to the motor case 50 and holds multiple cables C.

[0011] The fan case 70 is composed of an upper case 71 and a lower case 72 that are combined with each other. The fan case 70 has a scroll section 73 and a duct section 75. An intake port 74 for drawing gas into the fan case 70 is formed in the center above the scroll section 73, in other words, in the center of the upper case 71. The rotation axis A passes through the intake port 74.

[0012] The duct portion 75 extends along the duct axis B from the scroll portion 73. The duct axis B does not intersect the rotation axis A. The direction in which the duct axis B extends is perpendicular to the direction in which the rotation axis A extends. The duct axis B extends in the tangential direction of a circle in a plane perpendicular to the rotation axis A with the rotation axis A as the center. An air outlet 76 is formed at the tip of the duct portion 75. The scroll portion 73, which will be described in detail later, has a constant-width scroll flow path P that extends substantially annularly around the rotation axis A. The gas introduced into the constant-width scroll flow path P through the suction port 74 is discharged from the air outlet 76 of the duct portion 75. Incidentally, the area S4 of the suction port 74 shown in FIG. 2A is larger than the area S6 of the air outlet 76 shown in FIG. 2B.

[0013] The bearing holding 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 side of the closed impeller 30. The cylindrical portion 41 is substantially cylindrical. Inside the cylindrical portion 41, two bearings 48 that rotatably support the rotating shaft 13 are held. The two bearings 48 support substantially the center of the rotating shaft 13. The flange portion 42 is fixed to the upper end portion of the cylindrical portion 41. A collar 44 is fixed to the outer peripheral portion of the cylindrical portion 41. A vibration-proof material 45 is disposed between the collar 44 and the lower case 72. A nut 46 is screwed onto the outer peripheral surface of the cylindrical portion 41. The collar 44 and the vibration-proof material 45 are held between the nut 46 and the flange portion 42. The vibration-proof material 45 partitions the space in which the closed impeller 30 is housed and the space in which the motor 10 is housed.

[0014] The motor 10 includes a rotor 11, a coil 16, an insulator 17, a stator 18, and a printed circuit board 19. The rotor 11 includes a rotating shaft 13, a yoke 14, and a magnet 15. The rotation axis A of the motor 10 passes through the center of the rotating shaft 13 and is parallel to the rotating shaft 13. The closed impeller 30 is fixed to the tip of the rotating shaft 13. The yoke 14 is fixed to the base end of the rotating shaft 13. The magnet 15 is held on the outer peripheral portion of the yoke 14. The magnet 15 is cylindrical and magnetized with different polarities in the circumferential direction. The rotating shaft 13, the yoke 14, and the magnet 15 rotate integrally.

[0015] The stator 18 is disposed radially outside the magnet 15. Each of the 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. The printed circuit board 19 is connected with a plurality of cables C. By electrically connecting an electronic circuit provided outside the motor 10 and the printed circuit board 19 via the plurality of cables C, the energization of the plurality of coils 16 is controlled. When the plurality of coils 16 are energized, a magnetic force is generated between the stator 18 and the magnet 15. Thereby, the closed impeller 30 rotates together with the rotor 11.

[0016] FIG. 4 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 formed in a substantially disc shape. A plurality of blades 33 are provided on the hub 31 at regular intervals in the circumferential direction. The shroud 35 is formed in a substantially disc shape. The shroud 35 is fixed to the upper portions of the plurality of blades 33 and faces the hub 31 with a predetermined gap therebetween. An opening 352 is formed at the center of the shroud 35. The gas introduced into the fan case 70 through the suction port 74 passes through the gap between the blades 33 between the hub 31 and the shroud 35 through the opening 352 and flows radially outward, and flows in the constant-width scroll flow path P. A shaft hole 312 is formed at the center of the hub 31.

[0017] The outer peripheral edge 311 of the hub 31 is located radially outside the outer peripheral edge 351 of the shroud 35. That is, the diameter of the hub 31 is larger than the diameter of the shroud 35, but it is not limited thereto. For example, the diameter of the hub 31 and the diameter of the shroud 35 may be substantially the same.

[0018] Next, the constant-width scroll channel P will be described with reference to Figures 3, 5A, and 5B. Figure 5A is a cross-sectional view of BB in Figure 2B. Figure 5B is a cross-sectional view of CC in Figure 2B. As shown in Figure 3, the constant-width scroll channel P is defined by the inner surface 711 of the upper case 71 and the inner surface 721 of the lower case 72. The inner surface 711 is curved upward in the cross-sectional view of Figure 3 and extends in a substantially annular shape around the rotation axis A. The inner surface 721 is curved downward in the cross-sectional view of Figure 3 and extends in a substantially annular shape around the rotation axis A. The inner surfaces 711 and 721 face each other in a direction parallel to the rotation axis A.

[0019] As shown in Figures 3 and 5A, the inner surface 711 has an outer surface 712. The inner surface 721 has an outer surface 722 and an inner surface 723 that are radially opposite to each other. As shown in Figure 5A, the radial distance between the outer surface 722 and the inner surface 723 is constant in the circumferential direction. That is, the width W1 of the constant-width scroll flow path P is constant in the circumferential direction with respect to the rotation axis A.

[0020] As shown in Figure 5B, the radial distance between the outer edge 311 of the hub 31 of the closed impeller 30 and the outer surface 712 of the upper case 71 is constant in the circumferential direction. Therefore, the width W2 between the outer edge 311 of the hub 31 and the outer surface 712 of the upper case 71 is constant in the circumferential direction. In contrast to the constant-width scroll flow path P in this embodiment, a widening scroll flow path is known in which the width gradually increases in the circumferential direction toward the discharge port. While widening scroll flow paths have higher fan efficiency than constant-width scroll flow paths, they tend to produce more noise.

[0021] Figure 6A is an explanatory diagram of the intake port 74 of the comparative example blower 1x. Figure 6B is an explanatory diagram of the airflows F1 and F2 inside the upper case 71 of the comparative example blower 1x. The inner periphery of the intake port 74 is circular when viewed from the rotation axis A. As shown in Figure 6B, the upper case 71 has an opposing surface 715 that faces the shroud 35 of the closed impeller 30 with a predetermined gap between them.

[0022] As shown in Figure 6B, when the closed impeller 30 rotates, the airflow F1 flows from the intake port 74 through the opening 352 through the inside of the closed impeller 30 and into the constant-width scroll flow path P. The airflow F2 flows in the opening 352 through the gap between the outer edge 351 of the shroud 35 and the inner surface of the upper case 71, flowing in the opposite direction between the shroud 35 and the opposing surface 715. Therefore, the airflows F1 and F2, flowing in different directions, collide near the opening 352, generating a collision noise. It is thought that such collisions between airflows F1 and F2 occur around the entire circumference of the opening 352. Because the opening 352 is close to the intake port 74, the noise due to such collisions is significant in the comparative example blower 1x.

[0023] [First Embodiment] Next, the blower 1a of the first embodiment will be described. The suction port 74a of the blower 1a of the first embodiment has a different shape from the suction port 74 of the blower 1x of the comparative example. In all other respects, the blower 1a and blower 1x are the same. Figure 7A is an explanatory diagram of the suction port 74a of the blower 1a of the first embodiment. Figure 7B is an explanatory diagram of the airflow F3 and F4 inside the upper case 71a of the blower 1a of the first embodiment.

[0024] As shown in Figure 7A, the inner periphery of the suction port 74a includes a single arc-shaped edge 74a1 and a single straight edge 74a2. The arc-shaped edge 74a1 extends in an arc about the rotation axis A when viewed from the direction of the rotation axis A. The radius of the arc-shaped edge 74a1 is the same as the radius of the suction port 74 of the comparative example. The length of the arc-shaped edge 74a1 is longer than half the circumference of the suction port 74 of the comparative example. The straight edge 74a2 is continuous with the arc-shaped edge 74a1 and extends in a straight line when viewed from the direction of the rotation axis A. The straight edge 74a2 is located inside the suction port 74 of the comparative example but away from the rotation axis A. The length of the straight edge 74a2 is shorter than the diameter of the suction port 74 of the comparative example. The arc-shaped 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.

[0025] As shown in Figure 7B, airflow F3 flows through the opening 352 along the straight edge 74a2 of the intake port 74a and through the closed impeller 30 into the constant-width scroll flow path P. Airflow F4 flows in the opening 352 through the gap between the outer peripheral edge 351 of the shroud 35 and the inner surface of the upper case 71, flowing in the opposite direction between the shroud 35 and the opposing surface 715. Here, similar to the blower 1x of the comparative example, airflows F3 and F4, flowing in different directions from each other, collide near the opening 352. However, as shown in Figure 6B, airflow F2 collides with airflow F1, which flows along the intake port 74, near the opening 352. In contrast, as shown in Figure 7B, airflow F4 flows between the hub 31 and the shroud 35 through the opening 352 before colliding with airflow F3, which flows along the straight edge 74a2. Therefore, when airflow F4 collides with airflow F3, the direction of airflow F4 is approximately aligned with the direction of airflow F3, and the collision noise is suppressed. As a result, the blower 1a of the first embodiment has less noise than the blower 1x of the comparative example.

[0026] Figures 8A and 8B are illustrative diagrams of the blower 1a of the first embodiment, showing different angular positions of the suction port 74a. The reference line L1 extends from the rotation axis A to the side where the duct section 75 protrudes from the scroll section 73 and is parallel to the duct axis B. The angle line L2 extends radially outward from the rotation axis A and is perpendicular to the straight edge 74a2. In the blower 1a of Figure 8A, the angle between the reference line L1 and the angle line L2 in the counterclockwise direction is set to 110°. In the blower 1a of Figure 8B, the angle is set to 155°. Thus, the angular position of the suction port 74a may be changed according to various conditions.

[0027] [Second Example] Figure 9A is an explanatory diagram of the suction port 74b of the blower 1b of the second embodiment. Figure 9B is an explanatory diagram of the airflows F3 and F4 inside the upper case 71b of the blower 1b of the second embodiment. As shown in Figure 9A, the inner periphery of the suction port 74b includes two arc-shaped edges 74b1 and two straight edges 74b2. The arc-shaped edge 74b1 extends in an arc shape centered on the rotation axis A when viewed from the direction of the rotation axis A. The radius of the arc-shaped edge 74b1 is the same as the radius of the suction port 74 of the comparative example. The straight edge 74b2 is continuous with the arc-shaped edge 74b1 and extends in a straight line when viewed from the direction of the rotation axis A. The two arc-shaped edges 74b1 are point-symmetric with respect to the rotation axis A. The two straight edges 74b2 are point-symmetric with respect to the rotation axis A. Therefore, the suction port 74b is point-symmetric with respect to 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.

[0028] As shown in Figure 9B, the airflow F4 flows between the hub 31 and the shroud 35 via the opening 352 and then collides with the airflow F3 that flows along the straight edge 74b2 of the intake port 74b. Therefore, when the airflow F4 collides with the airflow F3, the direction of the airflow F4 is substantially aligned with the direction of the airflow F3, and the collision noise is suppressed. As a result, the blower 1b of the second embodiment has less noise than the blower 1x of the comparative example.

[0029] Figures 10A and 10B are illustrative diagrams of a second embodiment of the blower 1b with different angular positions of the suction port 74b. The angular line L2 extends radially outward from the rotation axis A and is perpendicular to one of the two straight edges 74b2. In Figure 10A, the blower 1b is set to an angle of 315°. In Figure 10B, the blower 1b is set to an angle of 45°. Thus, the angular position of the suction port 74b may be changed according to various conditions.

[0030] [Third Embodiment] Figure 11A is an explanatory diagram of the intake port 74c of the blower 1c of the third embodiment. Figure 11B is an explanatory diagram of the airflows F3 and F4 inside the upper case 71c of the blower 1c of the third embodiment. As shown in Figure 11A, the inner periphery of the intake port 74c includes three arc-shaped edges 74c1 and three straight edges 74c2. The arc-shaped edge 74c1 extends in an arc shape centered on the rotation axis A when viewed from the direction of the rotation axis A. The radius of the arc-shaped edge 74c1 is the same as the radius of the intake port 74 of the comparative example. The straight edges 74c2 are continuous with the arc-shaped edge 74c1 and extend in a straight line when viewed from the direction of the rotation axis A. The three arc-shaped edges 74c1 are point-symmetric with respect to the rotation axis A. The three straight edges 74c2 are point-symmetric with respect to the rotation axis A. Therefore, the suction port 74c is point-symmetric with respect to the rotation axis A. The area of ​​the suction port 74c is smaller than the area S4 of the suction port 74 in the comparative example, the area of ​​the suction port 74a in the first embodiment, and the area of ​​the suction port 74b in the second embodiment, but larger than the area S6 of the discharge port 76.

[0031] As shown in Figure 11B, the airflow F4 flows between the hub 31 and the shroud 35 via the opening 352 and then collides with the airflow F3 that flows along the straight edge 74c2 of the intake port 74c. Therefore, when the airflow F4 collides with the airflow F3, the direction of the airflow F4 is substantially aligned with the direction of the airflow F3, and the collision noise is suppressed. As a result, the blower 1c of the third embodiment has less noise than the blower 1x of the comparative example.

[0032] Figures 12A and 12B are illustrative diagrams of a third embodiment of the blower 1c with different angular positions of the suction port 74c. The angular line L2 extends radially outward from the rotation axis A and is perpendicular to one of the three straight edges 74c2. In Figure 12A, the blower 1c is set to an angle of 45°. In Figure 12B, the blower 1c is set to an angle of 75°. Thus, the angular position of the suction port 74c may be changed according to various conditions.

[0033] [Measurement Results] Next, the noise measurement results for 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. By keeping the rotation speed of the closed impeller 30 constant and changing the opening of a throttle valve (not shown) attached to the discharge port 76 of the duct section 75 for measurement purposes, the flow rate of air discharged from the discharge port 76 was changed to 190 L / min, 220 L / min, and 240 L / min, and the noise was measured at each flow rate. In addition, the noise was measured for blowers with different angles between the reference line L1 and the angle line L2 at each flow rate. For the blower 1a of the first embodiment, the noise was measured at angles of 20°, 65°, 110°, 155°, 200°, 245°, 290°, and 335°. In the second embodiment of the blower 1b, noise was measured at angles of 315°, 0°, 45°, and 90°. In the third embodiment of the blower 1c, noise was measured at angles of 15°, 45°, 75°, and 105°. Figure 13 is a table showing the noise measurement results.

[0034] At a flow rate of 190 L / min, the noise level of the comparative example blower 1x was 83.35 dB(A). In the first embodiment blower 1a, the noise level was reduced compared to the comparative example blower 1x across almost the entire range of the aforementioned angles. In particular, the noise reduction was significant at angles of 20°, 65°, 110°, and 155°.

[0035] At a flow rate of 220 L / min, the noise level of the comparative example blower 1x was 88.12 dB(A). In the first embodiment blower 1a, the noise level was reduced compared to the comparative example blower 1x across almost the entire range of the aforementioned angles. In particular, the noise reduction was significant at angles of 20°, 65°, 110°, 155°, and 335°.

[0036] At a flow rate of 245 L / min, the noise level of the comparative example blower 1x was 91.40 dB(A). In the first embodiment blower 1a, the noise level was reduced compared to the comparative example blower 1x across almost the entire range of the aforementioned angles.

[0037] Therefore, in the blower 1a of the first embodiment, noise is suppressed regardless of the flow rate by setting the above-mentioned angles within the ranges of 20° to 155° and 335° to 20°. In particular, in the blower 1a of the first embodiment, noise is sufficiently suppressed by setting the above-mentioned angles within the range of 110° to 155°.

[0038] In the blower 1b of the second embodiment, the noise level was reduced compared to the blower 1x of the comparative example across almost the entire range of the aforementioned angle, regardless of the flow rate. In particular, in the blower 1b of the second embodiment, noise is sufficiently suppressed by setting the aforementioned angle within the range of 315° to 45°.

[0039] In the blower 1c of the third embodiment, the noise level was reduced compared to that of the blower 1x of the comparative example across almost the entire range of the aforementioned angle, regardless of the flow rate. In particular, in the blower 1c of the third embodiment, noise is sufficiently suppressed by setting the aforementioned angle within the range of 45° to 75°.

[0040] Although preferred embodiments of the present invention have been described in detail above, the present invention is not limited to these specific embodiments, and modifications and changes are possible within the scope of the gist of the invention as described in the claims. [Explanation of Symbols]

[0041] 1a, 1b, 1c blower 10 motors 13 Rotation axis 30 Closed Impeller 31 Hubs 33 blades 35 Shroud 70 Fan Case 71a, 71b, 71c Upper case 72 Lower case 73 Scroll section 74a, 74b, 74c Inlet 74a1, 74b1, 74c1 Arc edges 74a2, 74b2, 74c2 straight edge 75 Duct section 76 Discharge port A axis of rotation B Duct axis P constant-width scroll channel

Claims

1. Motor and, The motor rotates a closed impeller which is a turbo fan, The fan case comprises the closed impeller mentioned above, The fan case includes a scroll section surrounding the closed impeller and a duct section extending from the scroll section. The scroll section has an intake port through which the rotation axis of the motor passes and through which gas is drawn in. The duct section has an outlet for discharging gas, A blower in which the inner circumferential edge of the intake port includes, when viewed from the direction of the rotation axis, an arc-shaped edge extending in an arc shape around the rotation axis and a straight edge extending in a straight line continuous with the arc-shaped edge.

2. The blower according to claim 1, wherein the inner periphery of the intake port includes a single arc-shaped edge and a single straight edge.

3. The blower according to claim 1, wherein the inner circumferential edge of the intake port includes two arc edges that are point-symmetric with respect to the axis of rotation, and two straight edges that are point-symmetric with respect to the axis of rotation.

4. The blower according to claim 1, wherein the inner circumferential edge of the intake port includes three arc edges that are point-symmetric with respect to the axis of rotation, and three straight edges that are point-symmetric with respect to the axis of rotation.

5. The blower according to any one of claims 1 to 4, wherein the scroll section has a constant-width scroll flow path that communicates with the intake port and has a constant width in the circumferential direction about the rotation axis.

6. A 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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