JP4613181B2 - Air blower - Google Patents

Description

  The present invention relates to an air blower for performing local ventilation, floor drying, measures against hot air, air circulation, and the like.

  Conventionally, an air blower for performing local ventilation, floor drying, measures against hot air, air circulation, etc. has a shape as shown in FIG. That is, the bell mouth 2 is provided on the suction port side of the cylindrical casing 1, and the impeller 3 including the hub 3 a and the plurality of blades 3 b provided around the hub 3 a is disposed in the casing 1. The impeller 3 is rotated by using an electric motor (not shown) disposed in 1 and air is discharged from the side opposite to the suction port.

Japanese Patent Application Laid-Open No. 2003-13892 and Japanese Patent Application Laid-Open No. 2007-92671 are patent documents that describe a blower designed to reduce power consumption and improve a blowing function.
JP 2003-13892 A JP 2007-92671 A

  FIG. 9A is a diagram showing the air flow of the conventional air blower. As indicated by the arrows in the figure, the swirling flow is generated in the vicinity of the outer end portion of the blade 3b (the arrow indicates the air flow). This swirling flow causes surging. Here, surging refers to a phenomenon in which the system including the turbo blower / turbo compressor and piping causes a kind of self-excited vibration, and the discharge pressure and gas amount fluctuate at a specific fixed period. .

  When such surging occurs, pressure fluctuations and vibrations occur, and the resonance sound with the wind noise generated by the blades 3b generates noise (sound pressure level) and causes a reduction in blowing capacity. SUMMARY OF THE INVENTION An object of the present invention is to provide an air blower that can suppress the generation of a swirling flow that causes surging as much as possible.

  In order to solve the above problems, the present invention is configured as follows.

  In an air blower comprising a hub and an impeller comprising a plurality of blades provided around the hub, an electric motor for rotating the impeller, and a substantially cylindrical casing that houses the impeller and the electric motor. The casing is formed by connecting a large-diameter tube body portion and a small-diameter main tube body portion via a reduced-diameter tube body portion whose diameter is gradually reduced, and the intermediate position of the axial height of the blades is reduced. It was set within 20% of the axial height of the blade in the front-rear direction of the boundary position between the head portion and the main tube body portion. The axial direction means the same direction as the rotating shaft of the impeller, and the front-rear direction refers to the direction from the suction port to the discharge port. The connection formation is a broad concept including integral molding.

  FIG. 9b is a diagram showing the air flow of the air blower according to the present invention (arrows in the figure represent the air flow). As can be seen from the comparison with FIG. 9a showing the conventional example, it can be seen that no swirling flow is generated in the vicinity of the outer end portion of the blade 12 and the air flows smoothly. Thus, since no swirling flow is generated, surging does not occur, and it is possible to reduce noise and suppress deterioration of the blowing capacity.

  Table 1 shows power consumption, noise level, maximum air volume, and maximum static pressure when the position of the impeller is changed in the casing according to the present invention. This number is explained below. In each figure, 10 represents an impeller, 12 represents a blade, 21 represents a main tube body, 22 represents an expanded tube body, and 23 represents a reduced diameter tube body. The line T represents the intermediate position of the blade 12 in the axial direction, the line A represents the boundary position between the reduced diameter tube body 23 and the main tube body 21, and H0 represents the height of the blade 12 in the axial direction. ing.

  FIG. 6 shows that the intermediate position (line T) of the axial height (H0) of the blade 12 exceeds 20% of H0 than the boundary position (line A) between the reduced diameter tube body 23 and the main tube body 21. The case where it is located in the pipe expansion trunk | drum 22 side is shown. The column of Table 1 (1) shows numerical values such as power consumption in this case. FIG. 7 shows a case where the intermediate position (line T) of the axial height (H0) of the blade 12 overlaps with the boundary position (line A) between the reduced diameter tube body 23 and the main tube body 21. It is. The column of Table 1 (2) shows numerical values such as power consumption in this case. In FIG. 8, the intermediate position (line T) of the axial height (H0) of the blade 12 exceeds 20% of H0 than the boundary position (line A) between the reduced diameter tube body 23 and the main tube body 21. The case where it is located in the main pipe trunk | drum 22 side is shown. The column of Table 1 (3) shows numerical values such as power consumption in this case.

  As shown in the column (1), when the T line is more than 20% of H0 than the A line and is on the tube expansion body side, the static pressure is low, and the air volume is reduced. On the other hand, as shown in the column (3), when the T line is more than 20% of H0 than the A line and is on the main tube body side, the static pressure is high and the air volume is large, but the noise is large. There is. On the other hand, as shown in the column (2), when the T line overlaps the A line, the static pressure is high and the air volume is large. Moreover, the noise level is low. Furthermore, less power consumption is required. If the intermediate position (line T) is set within 20% of H0 in the front-rear direction of the boundary position (line A) between the reduced-diameter tube body portion 23 and the main tube body portion 21, it is shown in the column (2). It shows a numerical value almost equivalent to the numerical value.

  Hereinafter, one preferred embodiment of the present invention will be described with reference to the drawings.

  1 is a perspective view of the present invention, FIG. 2 is a front view, FIG. 3 is a left side view, FIG. 4 is a right side view, and FIG. 5 is a front view in which a casing 20 is broken to make the internal structure visible. is there.

  As shown in FIGS. 1 and 2, the casing 20 of the blower / exhaust device according to the present invention includes an expanded body 22 having a large diameter from the suction port 50 side toward the discharge port 51, and a reduced diameter tube body having a diameter that gradually decreases. 23, a main tube body 21 having a small diameter is continuously formed in a substantially cylindrical shape. As shown in FIG. 3 and the like, the bell mouth 2 is provided on the tube expansion body 22, and a net-like safety guard 43 through which air can be ventilated is provided at the suction port 50. As shown in FIG. 4, a safety guard 44 is provided at the discharge port 51 corresponding to the end of the main tube body 21. A handle part 40 is provided at the upper part of the casing 20 for carrying and the like, and a leg part 41 for stabilizing the air blower is provided at the lower part.

  As shown in FIG. 5, an electric motor 31 fixed to the casing 20 with fixed blades 30 is installed in the casing 20. An impeller 10 is attached to a rotating shaft 32 driven and rotated by the electric motor 31, and the impeller 10 can be rotated. The impeller 10 includes a hub 11 and a plurality of blades 12 provided around the hub 11. The intermediate position of the axial height of the blade 12 is set within 20% of the axial height of the blade 12 in the front-rear direction of the boundary position between the reduced diameter tube body portion 22 and the main tube body portion 21. With the rotation of the impeller 10 configured as described above, air is sucked from the suction port 50 and discharged from the discharge port 51.

The perspective view of the air blower based on this invention. Similarly front view. Similarly left side view. Similarly right side view. Similarly a partially broken front view. Explanatory drawing which shows the positional relationship of an impeller. Explanatory drawing which shows the positional relationship of an impeller. Explanatory drawing which shows the positional relationship of an impeller. Explanatory drawing which shows an airflow. The perspective view of a prior art example.

Explanation of symbols

10. ・ Impeller 11 ・ ・ Hub 12 ・ ・ Bane 20 ・ ・ Case 21 ・ ・ Main tube barrel 22 ・ Tube barrel 23 ・ ・ Reduced tube barrel 50 ・ ・ Suction port

Claims (1)

  In an air blower comprising a hub and an impeller comprising a plurality of blades provided around the hub, an electric motor for rotating the impeller, and a substantially cylindrical casing that houses the impeller and the electric motor. The casing is formed by connecting a large-diameter tube body and a small-diameter main tube body via a reduced-diameter tube body whose diameter gradually decreases, and the intermediate position of the axial height of the blade is reduced. An air blower characterized in that it is set within 20% of the axial height of the blades in the front-rear direction of the boundary position between the head portion and the main tube body portion.