Blower

Abstract

To provide a blower reducing noise.SOLUTION: A blower is provided. The blower has a blower body including a centrifugal fan. The blower body is configured to suck air from both side surfaces by rotations of the centrifugal fan. The centrifugal fan is equipped with a supporting plate that has a rotation center, and a plurality of blades respectively provided on a first surface and a second surface of the supporting plate. At least a part of positions of the plurality of blades on the first surface, and at least a part of positions of the plurality of blades on the second surface are deviated in a circumferential direction, and / or a number of the plurality of blades on the first surface and a number of the plurality of blades on the second surface are different.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] Conventionally, there has been known an engine blower in which air is sucked in from two sides of a blower case by the rotation of a blower fan and ejected from an outlet on the outer circumferential surface of the blower case (see Patent Document 1). This blower fan has blower blades on both sides. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2001-140800 Summary of the Invention [Problem to be solved by the invention]

[0004] However, because electric motor-driven fans are much quieter than blowers driven by internal combustion engines, blowers driven by electric motors are widely used. While electric motor-driven blowers can be used regardless of location or time of day, there is a demand for quieter blowers. In view of the above, the present invention aims to provide a blower with reduced noise. [Means for solving the problem]

[0005] According to one aspect of the present invention, there is provided a blower. The blower has a blower body incorporating a centrifugal fan. The blower body is configured so that air can be drawn in from both sides thereof by the rotation of the centrifugal fan. The centrifugal fan includes a support plate having a rotation center and a plurality of blades provided on each of a first surface and a second surface of the support plate. The positions of at least some of the plurality of blades on the first surface and at least some of the plurality of blades on the second surface are misaligned in the circumferential direction, and / or the number of the plurality of blades on the first surface is different from the number of the plurality of blades on the second surface.

[0006] According to this aspect, it is possible to provide a blower that maintains a high air ejection force while reducing noise. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 2 is a perspective view of the blower as seen from above. [Figure 2] FIG. 2 is a perspective view of the blower as seen from below. [Figure 3] FIG. [Figure 4] 1A and 1B are side views of the blower body ((a) right side view, (b) left side view). [Figure 5] FIG. [Figure 6] FIG. 2 is a perspective view of a centrifugal fan. [Figure 7] FIG. 2 is a rear view of the centrifugal fan. [Figure 8] FIG. 2 is a left side view of the centrifugal fan. [Figure 9] 10 is a graph showing the difference in sound pressure level due to differences in the shape of the centrifugal fan. DETAILED DESCRIPTION OF THE INVENTION

[0008] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the accompanying drawings. Various features shown in the following embodiments can be combined with each other.

[0009] Incidentally, the program for realizing the software appearing in this embodiment may be provided as a non-transitory computer-readable medium, or may be provided so that it can be downloaded from an external server, or may be provided so that the program is started on an external computer and its functions are realized on a client terminal (so-called cloud computing).

[0010] In this embodiment, the term "unit" may also include, for example, a combination of hardware resources implemented by a circuit in the broad sense and software information processing that can be specifically realized by these hardware resources. In addition, this embodiment handles various types of information, which may be represented by, for example, physical values ​​of signal values ​​representing voltage and current, high and low signal values ​​as a binary bit set consisting of 0 or 1, or quantum superposition (so-called quantum bits), and communication and calculations may be performed on a circuit in the broad sense.

[0011] In addition, a circuit in the broad sense is a circuit realized by at least appropriately combining a circuit, circuitry, a processor, and memory, etc. That is, it includes an application specific integrated circuit (ASIC), a programmable logic device (e.g., a simple programmable logic device (SPLD), a complex programmable logic device (CPLD), and a field programmable gate array (FPGA)), etc.

[0012] FIG. 1 is a perspective view of the blower as seen from above. FIG. 2 is a perspective view of the blower as seen from below. FIG. 3 is a perspective view of the blower body. FIG. 4 is a side view of the blower body ((a) right side view, (b) left side view). FIG. 5 is a plan view of the blower body. FIG. 6 is a perspective view of the centrifugal fan. FIG. 7 is a rear view of the centrifugal fan. FIG. 8 is a left side view of the centrifugal fan. The blower of the present invention is a device for blowing air currents, and is used, for example, to blow away fallen leaves, garbage, pebbles, and the like. The blower 10 shown in FIG. 1 and the like has a blower body 1 and a blower pipe 20 attached (fixed) to the blower body 1.

[0013] In the following description, when looking at the blower body 1 in the drawings, the side where the blower pipe 20 is attached is defined as the "front side" or "tip side," and the side of the blower body 1 opposite the side where the blower pipe 20 is attached is defined as the "rear side" or "base side." Furthermore, when looking at the blower body 1 from above and behind in the drawings, the right side is defined as the "right" or "right side," and the left side is defined as the "left" or "left side." The blower pipe 20 is made of a cylindrical member, and as shown in Fig. 3, its base end is inserted into and fitted into the mounting part 6 of the blower body 1, so that it is detachably attached to the blower body 1. The blower pipe 20 may or may not be flexible.

[0014] The blower body 1 is provided with a battery mounting portion 5 on its front surface, and a battery 30 is attached to the battery mounting portion 5. The battery 30 supplies the electric power required to drive a motor 9, which will be described later. In addition, a handle 2 that can be held by an operator or the like is provided on the top of the blower body 1, and a power switch unit 3 for turning the power supply to the blower body 1 on and off is provided on the tip side of the handle 2. Furthermore, a frame-shaped support part 40 is attached to the lower left side of the blower body 1. This support part 40 protrudes outward beyond the fan covers 710 and 720 in the left-right direction when the blower body 1 is viewed from above.

[0015] This allows the operator to hold the handle 2 and the support portion 40 and support the blower with both hands, thereby maintaining the posture of the blower 10 stably. do Furthermore, because the support part 40 protrudes outward beyond the fan covers 710 and 720, the ventilation part 72 can be prevented from being blocked by the worker's clothing when the support part 40 is gripped. Even when the blower 10 is placed on the ground or a stand, the support part 40 and the bottom of the blower 10 come into contact with the ground or stand, so that the blower 10 can be kept horizontal. Furthermore, if the blower body 1 is dropped and the support part 40 hits the ground first, damage to the blower body 1 can be reduced.

[0016] An operating unit (trigger) 4 that controls the drive (control of the rotation speed, etc.) of the motor 9 is provided at the bottom of the distal end of the handle 2. For example, the rotation speed, etc. of the motor 9 can be adjusted depending on how much the operating unit 4 is pressed upward (towards the handle 2). The blower body 1 is provided on both the left and right side surfaces with a pair (two) ventilation parts 71, 72. Air sucked into the blower body 1 through the ventilation parts 71, 72 is ejected from the tip of the blower pipe 20 as an air flow.

[0017] The blower body 1 has a built-in centrifugal fan 8 at a position corresponding to the two ventilation portions 71, 72. The configuration of this centrifugal fan 8 is a feature of the present invention. 6, the centrifugal fan 8 includes a disk-shaped support plate 80 having a center of rotation, and a plurality of blades 81, 82 provided on each of the right side (first surface) and left side (second surface) of the support plate 80. Each of the blades 81, 82 is made up of a plate piece that curves toward the center of rotation. A recess 83 is formed in the center of the centrifugal fan 8, and the motor 9 is housed and fixed in this recess 83. In other words, the motor 9 is fixed to the centrifugal fan 8 so as to be located inside the centrifugal fan 8.

[0018] The centrifugal fan 8 is rotatably supported on the case of the blower body 1 via the central rotation axis of the motor 9 so that multiple blades 81 face the ventilation section 71 and multiple blades 82 face the ventilation section 72. With this configuration, the blower body 1 is configured so that, as the centrifugal fan 8 rotates, air can be sucked in from both side surfaces (ventilation portions 71, 72). However, according to the study by the present inventors, it has been found that the noise generated by the rotation of the centrifugal fan 8 increases depending on the number of blades 81 and 82 located on both sides of the support plate 80, their arrangement positions, etc.

[0019] Therefore, in the present invention, the positions of at least some of the blades 81 among the plurality of blades 81 and the positions of at least some of the blades 82 among the plurality of blades 82 are offset so that their joints (boundaries) with the support plate 80 do not overlap (are shifted) in the circumferential direction when the centrifugal fan 8 is viewed from the right side (first surface) of the support plate 80 or the left side (second surface) of the support plate 80. In this embodiment, the number of blades 81 and the number of blades 82 are the same, and the positions of all of the blades 81, 82 are shifted in the circumferential direction. This makes it possible to shift the phase of the peak of the noise generated by the blade 81 from the phase of the peak of the noise generated by the blade 82. Here, the noise generated by the entire centrifugal fan 8 is a combination of the noise generated by blade 81 and the noise generated by blade 82, but by shifting the phase of the peak of the noise generated by blade 81 from the phase of the peak of the noise generated by blade 82, it is possible to prevent or suppress an increase in the magnitude of the noise peak (sound pressure).As a result, blower 10 can reduce noise while maintaining a high air ejection force.

[0020] In this embodiment, one blade 81 provided on the right side (first surface) of the support plate 80 is positioned in the center between adjacent blades 82 provided on the left side (second surface) of the support plate 80. That is, as shown in Fig. 7, the distance D1 between the blade 81 and one adjacent blade 82 and the distance D2 between the blade 81 and the other adjacent blade 82 are set to be approximately equal. With this configuration, the phases of the peaks of the noise generated by the blades 81 and 82 can be more reliably shifted, making it easier to reduce noise from the entire centrifugal fan 8. Furthermore, by configuring each of the blades 81 and 82 as a plate piece that curves toward the center of rotation, the surface area is increased, and the suction force of the centrifugal fan 8 is further increased.

[0021] 8, in this embodiment, the distance (pitch) between adjacent blades 82 (81) gradually decreases in the circumferential direction in the order of P1, P2, P3, P4, and P5, then gradually increases, then gradually decreases again, and then gradually increases again. That is, the blades 82 (81) are spaced at uneven pitches. As shown in Figure 8, pressure fluctuations occur when the blades 82 (81) pass through the case tongue portion 73 of the blower body 1, and this is one of the causes of noise generation. If the blades 82 (81) are arranged at an equal pitch, the intervals between pressure fluctuations will be the same, which makes it easy for loud noise to occur at specific frequencies. In contrast, if the blades 82 (81) are arranged at an unequal pitch, the intervals between pressure fluctuations will differ for each blade 82 (81), which distributes the frequency of the generated noise and further reduces the magnitude of the noise peaks (sound pressure).

[0022] The maximum height of each blade 81 is set to be approximately equal to the maximum height of each blade 82. With this configuration, the amount of air sucked in from ventilation section 71 can be made closer to the amount of air sucked in from ventilation section 72, which also makes it easier to reduce noise. Such centrifugal fan 8 is preferably an integrated product (integral molding) of support plate 80 and multiple blades 81, 82. In this case, it is possible to reduce the weight of centrifugal fan 8 while increasing the mechanical strength of centrifugal fan 8. Examples of materials that can be used to form centrifugal fan 8 include resin materials such as polyolefin, polyamide, polyphenylene sulfide, and polycarbonate, and metal materials such as aluminum and its alloys.

[0023] The blower pipe 20 is fixed to the blower body 1 so as to extend in a direction (toward the tip) perpendicular to the center of rotation of the support plate 80 of the centrifugal fan 8. The support plate 80 of the centrifugal fan 8 is located on the central axis O of the blower pipe 20. In addition, when the blower body 1 is viewed from the opposite side (rear side) of the blower pipe 20, the handle 2 and the motor 9 are configured to be located inside the range corresponding to the outer diameter OD of the blower pipe 20, as shown in Figure 5. With the above-described configuration, the center of gravity of the blower body 1 can be brought closer to the central axis O of the blower pipe 20, thereby reducing the variation in mass and air suction volume between the left and right sides of the blower body 1, thereby improving the operability of the blower 10.

[0024] The ventilation sections 71, 72 are formed by penetrating the fan covers 710, 720 provided on both the left and right sides of the blower body 1. The opening areas of these ventilation sections 71, 72 are set to be approximately equal. This makes it possible to further reduce the variation in the amount of air suction between the left and right sides of the blower body 1. Specifically, the opening area of ​​the ventilation section 71 is set to S1 [cm 2 ], and the opening area of ​​the ventilation part 72 is S2 [cm 2 When S2 / S1 is 0.75 to 1.3, S2 / S1 is not particularly limited, but is preferably 0.75 to 1.3, more preferably 0.8 to 1.2, and even more preferably 0.9 to 1.1. In this embodiment, in order to make the opening areas approximately equal, the two ventilation sections 71, 72 (fan covers 710, 720) are configured to have approximately the same shape. In this case, the shape of the ventilation sections 71, 72 can be less likely to have an effect on reducing the variation in the amount of air suction between the left and right sides of the blower main body 1. This also prevents the design of the blower main body 1 (blower 10) from being impaired.

[0025] The blower body 1 incorporates a control board (not shown) that controls the operation of the motor 9. A computing element and a storage element are mounted on this control board. The arithmetic element is composed of, for example, a CPU (Central Processing Unit), an MPU (Micro Processing Unit), etc. The arithmetic element realizes various functions related to the blower main body 1 by reading out predetermined programs stored in the memory element. In other words, information processing by the software stored in the memory element is specifically realized by the arithmetic element. The number of arithmetic elements is not limited to one, and a plurality of arithmetic elements may be provided for each function, or a combination thereof may be used.

[0026] The memory element stores various pieces of information as defined above. This can be implemented, for example, as a storage device such as a solid state drive (SSD) that stores various programs related to the blower main body 1 executed by the computing element, or as a memory such as a random access memory (RAM) that stores temporarily required information related to program operations (arguments, arrays, etc.). The storage element also stores various programs and variables related to the blower main body 1 that are executed by the arithmetic element.

[0027] According to the blower 10 of the above embodiment, the centrifugal fan 8 has a distinctive configuration, so that it is possible to reduce noise while maintaining a high air ejection force. Furthermore, by positioning each part so that the center of gravity of the blower body 1 is closer to the central axis O of the blower pipe 20, the variation in mass and air suction volume between the left and right sides of the blower body 1 can be reduced, thereby improving the operability of the blower 10.

[0028] Furthermore, it may be provided in the following aspects. In the blower, one of the blades on the first surface is located in the center between adjacent blades on the second surface. In the blower, the centrifugal fan has a portion on at least one of the first surface and the second surface where the distance between adjacent blades varies in the circumferential direction. In the blower, the distance between adjacent blades gradually decreases and / or gradually increases along the circumferential direction. In the blower, the maximum height of the blades on the first surface is approximately equal to the maximum height of the blades on the second surface. In the blower, the centrifugal fan is an integrated unit of the support plate and the plurality of blades. The blower further includes a blower pipe, the blower pipe being fixed to the blower body so as to extend in a direction perpendicular to the rotation center of the support plate, and the support plate being positioned on the central axis of the blower pipe. The blower further comprises a handle and a motor, the handle and the motor being positioned within a range corresponding to the outer diameter of the blower pipe when the blower body is viewed from the opposite side of the blower pipe. In the blower, the motor is fixed to the centrifugal fan so as to be located inside the centrifugal fan. In the blower, the blower body has two ventilation sections, which are arranged at positions corresponding to the centrifugal fan on both side surfaces of the blower body, and the opening areas of the two ventilation sections are approximately equal. In the blower, the two vent portions have shapes that are approximately equal to each other. Of course, this is not the case.

[0029] As described above, various embodiments of the present invention have been described, but these are presented as examples and do not limit the scope of the invention in any way. The novel embodiments can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. Such embodiments and their modifications are intended to be included within the scope and spirit of the invention, as well as within the scope of the inventions and their equivalents as set forth in the claims.

[0030] For example, when the centrifugal fan 8 is viewed from the right side (first surface) of the support plate 80 or the left side (second surface) of the support plate 80, the positions of only some of the blades 81 and the positions of only some of the blades 82 may be offset so that the joints (boundaries) with the support plate 80 do not overlap (shift) with the blades 81 and 82 in the circumferential direction, thereby shifting the phase of the peak of the noise generated by the blade 81 from the phase of the peak of the noise generated by the blade 82; or the number of the plurality of blades 81 may be made different from the number of the plurality of blades 82, thereby shifting the phase of the peak of the noise generated by the blade 81 from the phase of the peak of the noise generated by the blade 82; or a combination of the above forms may be used.

[0031] Furthermore, from the viewpoint of dispersing the frequency of generated noise, it is sufficient that there are locations where the distance between adjacent blades 81, 82 varies in the circumferential direction, and the distance does not need to vary over the entire circumferential direction, and may vary only at any selected locations. In other words, the distance between adjacent blades 81, 82 may gradually decrease or increase at some locations and remain constant at other locations. Furthermore, even if the distance between adjacent blades 81, 82 changes, it does not need to be continuous, and may vary in stages. Furthermore, the two ventilation sections 71, 72 may have different shapes as long as their opening areas are set to be approximately equal.

[0032] Furthermore, instead of providing the support part 40 on the lower left side of the blower body 1, it may be provided on the lower right side of the blower body 1, or it may be provided on both the lower left side of the blower body 1 and the lower right side of the blower body 1. This allows the operator to grip the blower 10 with force regardless of their dominant hand. [Example]

[0033] EXAMPLES The present invention will be explained in more detail below with reference to examples and comparative examples, but the present invention is not limited to these examples.

[0034] (Example) The centrifugal fan shown in Figure 6 was manufactured using polyamide. This centrifugal fan has a plurality of blades on both sides at unequal pitches, and the blades on the right side and the blades on the left side are all misaligned in the circumferential direction. Next, the manufactured centrifugal fan was used to assemble the blower shown in FIG. 1 etc.

[0035] (Comparative Example) Polyamide was used to manufacture a centrifugal fan with blades all aligned on both sides of the support plate. In this centrifugal fan, the blades on both sides are arranged at equal pitches, and the blades on the right side and the blades on the left side are all aligned in the circumferential direction (i.e., there is no misalignment). Next, the manufactured centrifugal fan was used to assemble the blower shown in FIG. 1 etc.

[0036] Next, the blowers of the example and the comparative example were operated under the same conditions, and the noise generated during this operation was measured. The results are shown in Figure 9. Figure 9 is a graph showing the difference in sound pressure level due to differences in the shape of the centrifugal fan. As indicated by the arrows in FIG. 9, the blower of the example had reduced noise peaks in the primary component of fan rotation, etc., compared to the blower of the comparative example. [Explanation of symbols]

[0037] 10: Blower 1: Blower body 2: Handle 3: Power switch section 4:Operation section 5: Battery mounting section 6: Mounting part 71: Ventilation section 710: Fan cover 72: Ventilation section 720: Fan cover 73: Case tongue 8: Centrifugal fan 80: Support plate 81: Feather 82: Feather 83: Recess 9: Motor 20: Blower pipe 30: Battery 40: Support part D1: Separation distance D2: Separation distance O: Central axis P1: Distance (pitch) P2: Distance (pitch) P3: Distance (pitch) P4: Distance (pitch) P5: Distance (pitch) OD:Outer diameter

Claims

1. A blower, The blower includes a blower body that houses a centrifugal fan and a motor that rotates the centrifugal fan, and a blower pipe that is fixed to the front side of the blower body and has a central axis. the blower body is configured to be able to suck air from both side surfaces in a left-right direction perpendicular to the central axis by rotation of the centrifugal fan caused by operation of the motor, the centrifugal fan has a center of rotation extending along the left-right direction, and includes a support plate located on the central axis, and a plurality of blades provided on each of a first surface and a second surface of the support plate, the positions of at least some of the plurality of blades on the first surface and the positions of at least some of the plurality of blades on the second surface are misaligned in the circumferential direction, and / or the number of the plurality of blades on the first surface and the number of the plurality of blades on the second surface are different, a blower, wherein the motor is fixed to the centrifugal fan so as to be located inside the centrifugal fan when viewed from a direction perpendicular to the center of rotation;

2. 2. The blower of claim 1, A blower in which one of the blades on the first surface is located in the center of adjacent blades on the second surface.

3. The blower according to claim 1 or 2, The centrifugal fan is a blower, wherein at least one of the first surface and the second surface has a portion where the distance between adjacent blades varies in the circumferential direction.

4. 4. The blower of claim 3, A blower in which the distance between adjacent blades gradually decreases and / or gradually increases along the circumferential direction.

5. The blower according to any one of claims 1 to 4, A blower, wherein a maximum height of the blades on the first surface is approximately equal to a maximum height of the blades on the second surface.

6. The blower according to any one of claims 1 to 5, The centrifugal fan is a blower that is an integrated unit of the support plate and the plurality of blades.

7. A blower according to any one of claims 1 to 6, Further, a handle is provided on the upper side of the blower body, A blower, wherein the handle and the motor are located within a range corresponding to the outer diameter of the blower pipe when the blower body is viewed from the rear.

8. The blower according to any one of claims 1 to 7, The blower body has two vents, The two ventilation sections are arranged on both sides of the blower body in the left-right direction at positions corresponding to the centrifugal fan, and the opening areas of the two ventilation sections are approximately equal.

9. 9. The blower of claim 8, The two vents have substantially the same shape as each other.

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