Cylindrical air blower

Abstract

To reduce noise in a cylindrical air blower with which diffusion of an airflow leaving an air blow-out port is reduced.SOLUTION: A cylindrical air blower includes a cylinder 110 provided with an air suction port 120 in a rear end thereof and an air blow-out port 130 in a front end thereof, a fan 152 provided within the cylinder 110, and an arm 170 attached to the cylinder such that the cylinder can rotate. When a direction orthogonal to a front-back direction and a left-right direction of the cylinder 110 is defined as a vertical direction, a through hole for reducing noise is provided below the cylinder 110.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a tubular fan. [Background technology]

[0002] Tubular fans are used in tunnel fans and blower application products such as hair dryers and air purifiers, as they create airflow in a limited area with little diffusion of the air flow.

[0003] Patent Document 1 discloses an airflow generating device with little diffusion of airflow, which includes a housing with an air intake at a first end and an air outlet at a second end, with a rotary fan and air guide vanes (flow straightening plates) between them. The rotary fan has blades, and it is said that noise can be reduced by changing the number of blades and vanes. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Special Publication No. 2007-529681 Summary of the Invention [Problem to be solved by the invention]

[0005] The inventors have been developing a fan that can be used in relatively quiet environments such as offices and can change direction to blow air to specific locations, such as where people are present. However, because the fan's housing is exposed in order to change direction, noise can be a concern compared to ceiling-mounted fans. Therefore, the inventors set out to reduce noise when developing a cylindrical fan with less diffusion of airflow. [Means for solving the problem]

[0006] The present invention provides a tube having an air intake port at its rear end and an air outlet port at its front end; a fan provided inside the cylinder; an arm attached to the barrel so that the barrel is rotatably mounted; A direction perpendicular to the front-rear direction and the left-right direction of the cylinder is defined as an up-down direction, and a through hole for reducing noise is provided on the lower side of the cylinder. It is a cylindrical blower.

[0007] In the present invention, the through hole may be elongated in the front-rear direction and may be provided in plurality. [Effects of the Invention]

[0008] In the present invention, noise can be reduced by providing an opening in the cylindrical portion of the cylindrical blower in the region surrounding the fan. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a perspective view of a cylindrical fan according to a first embodiment; [Figure 2] 1 is an axial cross-sectional view of a cylindrical fan according to a first embodiment. [Figure 3] 1 is a simulation diagram of airflow in a cylindrical fan according to the first embodiment. [Figure 4] 1 is a diagram showing the frequency and sound level of the sound generated by the cylindrical fan of the first embodiment. [Figure 5] FIG. 10 is a perspective view of a cylindrical fan according to a modification of the first embodiment. [Figure 6] 10 is a diagram showing a simulation of airflow for examining the cylindrical fan of the second embodiment. [Figure 7] 10 is a perspective view of a cylindrical fan according to a second embodiment of the present invention; [Figure 8] 10 is a perspective view of a cylindrical fan according to a third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] <Embodiment 1> <Configuration> The cylindrical fan 100 of this embodiment can be attached to a wiring duct 180, and the direction of the airflow can be changed as needed.

[0011] Fig. 1 is a perspective view of cylindrical fan 100B. In the following description, the terms F direction, B direction, U direction, and D direction will be used, based on the axis AX in Fig. 1. The direction perpendicular to the axis AX and the up-down direction will sometimes be referred to as left and right.

[0012] 1, tubular blower 100B includes a tube 110 having air intake 120 at its rear end and air outlet 130 at its front end, and tube 110 is divided into rear tube portion 111 and front tube portion 112B. It includes arm 170 rotatably attached to the side surface of rear tube portion 111, and mounting portion 178 at the other end of arm 170 for mounting to wiring duct 180.

[0013] Three types of front tubular sections were prototyped: front tubular section 112A with no through-holes on the side surface; front tubular section 112B with through-holes 115B (openings) in the lower half of the side surface; and front tubular section 112C with through-holes 115C (openings) around the entire periphery of the side surface. Figure 1 shows front tubular section 112B as a representative example. Cylindrical fans using front tubular sections 112A, 112B, and 112C are referred to as cylindrical fans 100A, 100B, and 100C, respectively, and are collectively referred to as front tubular section 112 and cylindrical fan 100. Through-holes 115B and 115C are also collectively referred to as through-holes 115.

[0014] The through holes 115 are provided in multiple lengths in the front-to-rear direction. This is because there are required "pillars" between the through holes to provide the front tube portion 112 with mechanical strength, and the size of the through holes is set to a level that prevents fingers from getting stuck in them, ensuring safety.

[0015] The axis AX, which is the orientation of the cylindrical fan 100, can be rotated horizontally by rotating the arm 170 in the Φ direction relative to the mounting part 178. In addition, the orientation can be changed from downward to upward as appropriate by rotating the rear cylindrical part 111 in the θ direction relative to the arm 170.

[0016] Cylindrical fan 100 can be turned on and off and its airflow volume controlled by communication using radio waves or infrared rays from control device 190, which may be a tablet, smartphone, PC, or remote control.

[0017] 2(a) is a cross-sectional view including axis AX of cylindrical fan 100B. Inside cylindrical fan 100B, there are power supply 140, motor 151, fan 152 rotated by motor 151, and rectifier vane 160. As fan 152 rotates, airflow W passes through the space between power supply 140 and rear cylindrical portion 111 and is released in direction F.

[0018] 2(b) is a view of the cylindrical fan 100B as seen from the F side (front side) of the air outlet 130. It can be seen that there are eight rectifying plates 160 and three fans 152.

[0019] The length of cylindrical blower 100B from air intake 120 to air outlet 130 is 190 mm, the length of rear cylindrical portion 111 is 65 mm, the length of front cylindrical portion 112 is 125 mm, and the outer diameter of air intake 120 / air outlet 130 is 85 mm, but cylindrical blowers of different sizes are also under consideration.

[0020] <Fan and through-hole> Referring again to FIG. 2(a), a point S1 is defined as a projection of a plane including the front end 152F of the fan and perpendicular to the axis AX onto the front cylindrical portion 112, and a point S2 is defined as a projection of a plane including the rear end 152B of the fan and perpendicular to the axis AX onto the front cylindrical portion 112. The distance between S1 and S2 is L. f The midpoint between S1 and S2 is S3. The range where the through holes 115 are provided is L h In the front cylindrical portion 112B, the range L that contacts the side surface of the fan 152 is f The range L of the through hole 115 is h The length of the through hole is L h The diameter is 45 mm, the width of the through holes is 5.2 mm, the spacing between the through holes is 2.6 mm, and the number of through holes is 16.

[0021] <Air flow simulation> Figure 3(a) shows the simulation results of the internal air flow of a cylindrical fan 100A using a front tubular portion 112A without through holes, and Figure 3(b) shows the simulation results of the internal air flow of a cylindrical fan 100C using a front tubular portion 112C with through holes 115C around the entire circumference.

[0022] 3(a) and 3(b) show the widths DA and DC of the airflow at the air outlet 130. The narrower width DC compared to DA indicates that the through-hole 115C affects the width of the airflow. In the original diagram, the color changes from blue (weak) to green (medium) to yellow (slightly strong) to red (strong) as the wind speed changes from weak to strong. However, the arrows indicating the DA airflow are dark gray (original green (medium)), and the arrows indicating the DC airflow are light gray (original yellow (slightly strong)). This consistent result indicates that the smaller the airflow width, the stronger the airflow. Therefore, it can be assumed that providing the through-hole 115C narrows the width of the airflow, thereby strengthening the directionality of the airflow and reducing the diffusion of the airflow.

[0023] 3(a) is dark gray (original red (strong)), and the airflow is medium (original green (medium)) at point Q in FIG. 3(a) behind fan 152. The same is true for the front and rear sides of fan 152 in FIG. 3(b). Meanwhile, in FIG. 3(b), the airflow exiting through hole 115C and the airflow entering through hole 115C are not depicted, and it can be seen that the air intake and blowout at through hole 115C is so small that it is not shown, and that through hole 115C does not substantially function as an "air intake port" or an "air outlet port."

[0024] 3(a) and (b), a difference can be seen, particularly near the front end 152F of the fan, where the width of the airflow is wider in Fig. 3(a) and narrower in Fig. 3(b). Based on this, we believe it would be best to position the through-hole so that it includes at least point S1 when the front end 152F of the fan is projected onto the cylinder.

[0025] The inventors have hypothesized the following model for the effect of through-holes on airflow. For example, at point T near the front tube portion 112 in Figure 3(a), if the fan is at the rear, the pressure is high; if the fan is at the front, the pressure is low. As the fan rotates, these high and low pressure states alternate, resulting in pressure fluctuations. It is estimated that if through-hole 115 is opened in the front tube portion 112, air can instantly flow in and out through the through-hole 115, thereby reducing pressure fluctuations. Considering this pressure fluctuation as one of the causes of noise, it can be explained why noise can be reduced by drilling through-holes in the tube next to the fan. Prior to the experiment, it was assumed that the through-holes would act as a sound passageway, causing noise to escape and increasing noise levels. In reality, even if sound comes out of the through-hole, the object being blown by the air is in the front (direction F), and in most cases, people are also in the front, whereas the sound coming out of the through-hole spreads mainly in direction D, etc. Therefore, it can be said that the cylindrical fan 100A or 100B, which is a ceiling-mounted fan, has a structure that is particularly suitable for reducing noise when installed on the ceiling of a store, office, etc.

[0026] <Noise measurement results> For cylindrical fans 100A, 100B, and 100C, the noise measurement results when the same power was input were 38.9 dB, 36.6 dB, and 36.1 dB, respectively. Note that the noise (dB) is an SPL (Sound Pressure Level) value with A-weighting, which is a frequency weighting corresponding to human hearing.

[0027] The noise mentioned above is the overall noise, but Fig. 4 shows the results of noise spectrum measurements broken down by sound frequency. The vertical axis is the SPL for each frequency, the horizontal axis is the sound frequency f (Hz), and lines 100A, 100B, and 100C show the noise by frequency for cylindrical fans 100A, 100B, and 100C, respectively. In Fig. 4, the trend may differ depending on the frequency, but at least in the frequency range enclosed by the square, the SPL is in the relationship 100A > 100B > 100C, confirming that a noise reduction effect can be observed at 100C.

[0028] From the viewpoint of noise reduction, cylindrical fan 100C having through holes formed around the entire circumference of front cylindrical portion 112 is suitable, but providing through holes on the U side (upper side) of front cylindrical portion 112 poses another problem of dust intrusion. Taking this into consideration, cylindrical fan 100B having through holes formed on the lower side of front cylindrical portion 112 is preferable.

[0029] If the through-hole 115 is extended forward from the side of the fan of the front cylindrical portion 112, the directivity of the airflow, which is a feature of the cylindrical fan, may be lost, and there is a concern that the flow may be diffused. Therefore, it is preferable that the through-hole is not extended too far forward. The length added to the front side with respect to the point S1 on which the front end 152F of the fan is projected is L. f I think the following is good.

[0030] <Rectifier plate> 2(a) and 2(b) have the function of rectifying the airflow and also function to prevent fingers from touching the fan 152. Although the number of rectifying plates 160 extending outward from the axis AX is eight, the number may be four, six, eight, twelve, etc.

[0031] <Power supply> Power supply 140 is installed between air intake 120 and fan 152 in tube 110. Power supply 140 has a cylindrical outer shape and is compact so as to ensure an air passage between power supply 140 and the inner surface of tube 110. Power supply 140 converts AC commercial power input from a wiring duct into DC.

[0032] The power supply may be provided, for example, in mounting portion 178 rather than inside cylinder 110. This reduces air resistance inside the cylinder and increases the air volume. Furthermore, rear cylinder portion 111 may be eliminated.

[0033] <Operation control> The cylindrical fan can be operated on a schedule using the control device 190. Scheduled operation allows the fan to be turned on when the store opens or when work starts, and turned off when the store closes or when work ends, allowing for strong or weak airflow depending on the time of day. Sensor-linked operation can also be performed using a sensor that can communicate with the control device 190, allowing the fan volume to be controlled according to the temperature, humidity, and human density measured by the sensor.

[0034] <First Modification of Cylindrical Fan 100C> Cylindrical fan 100C, which has through-holes 115C formed around the entire circumference of the front tubular portion, is excellent in terms of noise reduction, but has the problem of dust getting inside. Therefore, in cylindrical fan 100D, which is variation 1 and whose perspective view is shown in Figure 5, plate 117, which corresponds to a roof, is installed above through-hole 115C with a small space between them. As a result, even if through-holes 115C are formed around the entire circumference, dust is blocked by plate 117, making it difficult for dust to enter the interior of the cylinder. Note that plate 117 may also be provided around the entire circumference of front tubular portion 112C.

[0035] <Second Modification of Cylindrical Fan 100C> In the cylindrical fan 100E (not shown) of Variation 2, through-holes 115C are provided around the entire circumference, and at least the upper through-holes 115C are covered with a thin film on the inner or outer surface. This film is, for example, approximately 0.2 mm, 0.1 mm, or 0.05 mm thick and is made of a flexible material, allowing it to vibrate in response to fluctuations in air pressure caused by fan rotation. This achieves both dust prevention and noise reduction. Note that openings or through-holes covered with a film that can vibrate in response to fluctuations in air pressure function similarly to ordinary openings or through-holes in terms of noise reduction, and therefore will be referred to by the same name (openings or through-holes), with the added explanation that they are "openings or through-holes that can transmit instantaneous pressure fluctuations inside the cylinder to the outside of the cylinder" as needed.

[0036] <Embodiment 2> <Configuration> The cylindrical fan 100F of the second embodiment is the same as the fan 100B in the first embodiment in other respects, except that it has a through hole 114B in the lower half of the periphery of the rear cylindrical portion 111B in addition to the through hole 115B near the fan.

[0037] As a preliminary step to this embodiment, we investigated the effect of providing "through holes 114C" around the entire circumference of the rear tubular portion 111 of 100A, which does not have any through holes near the fan. The results of the airflow simulation in this case are shown in Figure 6. The width DE of the airflow at the air outlet 130 is slightly larger than DA in Figure 3(a).

[0038] Based on the above findings, a prototype of cylindrical fan 100F was produced. A perspective view of the prototype is shown in Fig. 7. It was found that cylindrical fan 100F did not achieve much further noise reduction compared to cylindrical fan 100B, but it did increase the air volume slightly. In other words, when compared at the same air volume, noise was slightly reduced.

[0039] From this result, it is suitable to use through hole 114 (through hole 114C or through hole 114B with dust countermeasure taken into consideration) together with through hole 115 (through hole 115C or through hole 115B with dust countermeasure taken into consideration). Note that through hole 114 may be provided as an elongated hole continuous with through hole 115.

[0040] <Embodiment 3> <Configuration> In a cylindrical fan 100G of the third embodiment, an opening 115G near the fan is provided in a front cylindrical portion 112G.

[0041] 8, an opening 115G is provided in the lower half of the side surface near the fan 152. A guard wire 116 is provided to prevent fingers from getting stuck in the opening 115G.

[0042] In this embodiment, the area of ​​the opening can be made larger than that of the through-hole-shaped opening used in the first and second embodiments, and the noise reduction effect is enhanced.

[0043] Although opening 115G is provided in the lower half of front tube portion 112G in the above embodiment, it may be provided around the entire circumference. In this case, the front tube may be supported by, for example, a shaft provided on the motor side, or by guard wire 116.

[0044] <Modification> The above describes an embodiment of a tubular fan according to the present invention. However, the exemplified tubular fan can be modified, for example, as follows, and it goes without saying that the present invention is not limited to the tubular fan as shown in the above embodiment.

[0045] Although each embodiment has been described as a simple cylindrical fan, the present invention can be applied to fan application products such as dryers, which are cylindrical fans that blow warm air, air purifiers with built-in air cleaning filters or disinfection, sterilization, and virus inactivation devices, and large fans used for tunnel ventilation, etc. Furthermore, the present invention may be used, for example, as a fan in the front stage of a bladeless fan.

[0046] The term "cylindrical" is not limited to a cylindrical shape, but may also refer to a curved cylindrical shape as described in Prior Art Document 1. The cylinder may be linear with respect to the axis AX as in each embodiment, or the cylinder may be curved.

[0047] In each embodiment, the front tube, which adjusts the direction of the fan and airflow, and the rear tube, which houses the power supply, are separate components, but they may also be an integrated component. Furthermore, if the front and rear tubes are separated, the fan may be located inside the rear tube. Furthermore, the portion of the front tube near the fan and the portion further forward may be separate components. The rear tube, which houses the power supply, may not be required.

[0048] In each embodiment, the arm is attached to the side of the rear cylinder, but the attachment position of the arm is not limited to this, and it may be attached to the front cylinder or to the air intake port side.

[0049] As a blower having a shape intermediate between a fan and a cylindrical blower, for example, there is a fan / circulator provided with a protective frame surrounding the fan, but when it is necessary to clarify the difference between these and the present invention, it is preferable that the length of the tube (total length of the front tube and the rear tube) is at least 1 time, preferably at least 1.3 times, and more preferably at least 1.5 times longer than the outer diameter of the air intake. Also, it is preferable that the opening (through hole) is provided so as to include the length from point S1 where the front end 152F of the fan is projected to point S2 where the rear end 152B of the fan is projected, and it is preferable that it is provided so as to include the length from S1 to midpoint S3, and it is preferable that it is provided so as to include S1. It is preferable that a straightening plate is provided in front of the fan inside the tube. At the front side of the front end of the fan of the tube, at least length L f or longer than L h It is preferable that there is an area without the above openings (openings of a size that have little effect on the air flow may be provided).

[0050] The "lower side" where the through-holes are provided in cylindrical fan 100B may be the lower side when the periphery of the front cylinder is divided into two parts, "upper and lower." Furthermore, when the periphery of the front cylinder is divided into four parts, "upper, lower, right side, and left side," the right side and left side may be included, may be partially included, or may not be included.

[0051] Although the cylindrical fan of the present invention is described in each embodiment as being mounted on a wiring duct rail, the cylindrical fan of the present invention may be mounted directly on the ceiling without using a wiring duct rail. Also, the cylindrical fan does not have to be a ceiling-mounted type, and may be used without being fixedly installed.

[0052] The through-hole is preferably a hole that is long in the direction of the axis AX, and the ratio of the length in the axial direction to the width direction is preferably 3 to 20 times, more preferably 5 to 10 times.

[0053] It should be noted that the above-described embodiments disclosed herein are illustrative in all respects and are not intended to be limiting. Therefore, the technical scope of the present invention should not be interpreted solely by the above-described embodiments, but should be defined by the claims. Furthermore, all modifications within the scope and meaning equivalent to the claims are included. [Explanation of symbols]

[0054] 100, 100A, 100B, 100C, 100D, 100E, 100F, 100G cylindrical blower 110 tubes 111 Rear cylinder part 112, 112A, 112B, 112C, 112G Front cylinder part 114, 114B, 114C through hole 115, 115B, 115C through hole 115G opening 116 Guard wire 117 board 120 Air Intake 130 Air outlet 140 Power supply 151 Motor 152 fans 152F front end of fan 152B Fan rear end 160 Rectifier plate 170 Arm 178 Mounting part 180 Wiring duct 190 Control Device

Claims

1. a tube having an air intake port at its rear end and an air outlet port at its front end; a fan provided inside the cylinder; an arm attached to the barrel so that the barrel is rotatably mounted; A direction perpendicular to the front-rear direction and the left-right direction of the cylinder is defined as an up-down direction, and a through hole for reducing noise is provided on the lower side of the cylinder. Cylindrical blower.

2. The through holes are elongated in the front-rear direction and are provided in plurality. The cylindrical fan according to claim 1.

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