Blower

Abstract

To provide a technique capable of suppressing generation of loud noise.SOLUTION: A blower disclosed herein may comprise a prime mover, a fan configured to be driven by the prime mover, an air flow pipe through which an air flow generated by the fan flows, a plate portion disposed inside the air flow pipe and having a side surface along a direction in which the air flow flows, and a protruding portion protruding from the side surface near a downstream end of the plate portion in a direction in which the air flow is blocked.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The technology disclosed in this specification relates to a blower. [Background technology]

[0002] Patent Document 1 discloses a blower that includes a prime mover, a fan driven by the prime mover, an air duct through which the airflow generated by the fan flows, and a plate portion that is disposed inside the air duct and has a side surface aligned with the direction of the airflow. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-123186 Summary of the Invention [Problem to be solved by the invention]

[0004] In the blower described above, vortexes may periodically occur at the downstream end of the plate portion. The frequency at which such vortexes occur varies depending on the speed of the airflow, and therefore varies depending on the rotation speed of the fan. Therefore, depending on the rotation speed of the fan, the frequency at which the vortexes occur may match the resonant frequency of the plate portion or the air duct, or the resonant frequency of the air duct itself, which may cause loud noise. This specification provides technology that can suppress the generation of loud noise in a blower. [Means for solving the problem]

[0005] The blower disclosed in this specification may include a prime mover, a fan driven by the prime mover, an air duct through which an air flow generated by the fan flows, a plate portion disposed inside the air duct and having a side along the direction in which the air flow flows, and a protrusion protruding from the side near the downstream end of the plate portion in a direction that blocks the air flow.

[0006] According to the above configuration, the protrusion provided near the downstream end of the plate portion can suppress the generation of periodic vortexes at the downstream end of the plate portion, thereby suppressing the generation of loud noise due to resonance of the plate portion and the air duct. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 2 is a perspective view of a blower 2 according to the embodiment. [Figure 2] FIG. 2 is a cross-sectional view of a blower 2 according to the embodiment. [Figure 3] FIG. 2 is a side view showing the inside of a fan case 24 of a blower 2 according to the embodiment. [Figure 4] 2 is a perspective view of the vicinity of an exhaust port 12 of the blower 2 according to the embodiment. FIG. [Figure 5] 2 is a cross-sectional view of the vicinity of an exhaust port 12 of the blower 2 according to the embodiment. FIG. [Figure 6] 2 is a vertical cross-sectional view of the vicinity of an exhaust port 12 of the blower 2 according to the embodiment. FIG. [Figure 7] 10 is a graph showing the relationship between the motor rotation speed and the noise level for a blower 2 according to an example and a blower 2 according to a comparative example. [Figure 8] FIG. 10 is a cross-sectional view of the vicinity of an exhaust port 12 of a blower 2 according to a modified example. [Figure 9] FIG. 10 is a cross-sectional view of the vicinity of an exhaust port 12 of a blower 2 according to another modified example. [Figure 10] FIG. 10 is a cross-sectional view of the vicinity of the exhaust port 12 of the blower 2 according to yet another modified example. DETAILED DESCRIPTION OF THE INVENTION

[0008] Representative, non-limiting embodiments of the present invention are described in detail below with reference to the drawings. This detailed description is intended simply to provide those skilled in the art with details for implementing preferred embodiments of the present invention and is not intended to limit the scope of the present invention. Additionally, the additional features and inventions disclosed can be used separately or in conjunction with other features and inventions to provide further improved blowers and methods of using and manufacturing the same.

[0009] Furthermore, the combinations of features and steps disclosed in the following detailed description are not essential to practicing the invention in its broadest sense, but are described solely to specifically illustrate exemplary embodiments of the invention. Furthermore, the various features of the following exemplary embodiments and those described in the claims do not necessarily have to be combined in the exact embodiments described herein or in the exact order listed to provide additional and useful embodiments of the invention.

[0010] All features described in this specification and / or claims are intended to be disclosed individually and independently of one another as limitations to the specific features described in the original disclosure and claims, apart from the configuration of features described in the examples and / or claims. Furthermore, all numerical ranges and group or aggregate descriptions are intended to disclose intermediate configurations thereof as limitations to the specific features described in the original disclosure and claims.

[0011] In one or more embodiments, the height of the protrusion in the direction in which it blocks the airflow may be within a range of 1% to 50% of the thickness of the plate portion.

[0012] According to the above configuration, the generation of periodic vortex flows can be suppressed without significantly affecting the airflow volume of the blower.

[0013] In one or more embodiments, the width of the protrusion, relative to the direction of airflow, may be in the range of 1% to 50% of the minimum width of the plate portion.

[0014] According to the above configuration, the generation of periodic vortex flows can be suppressed without significantly affecting the airflow volume of the blower.

[0015] In one or more embodiments, the protrusions may be provided discretely.

[0016] According to the above configuration, the influence on the air flow rate of the blower can be made smaller than when the protruding portion is provided continuously.

[0017] In one or more embodiments, the protrusion may be continuous.

[0018] According to the above configuration, when the plate portion provided with the protrusion is manufactured by integral molding of a resin material, the workability of the die cutting can be improved.

[0019] In one or more embodiments, the protrusion may be provided on only one of the side surfaces of the plate portion, and the protrusion may not be provided on the other side surface of the plate portion.

[0020] According to the above configuration, the influence on the air flow rate of the blower can be made smaller than when protrusions are provided on both side surfaces of the plate portion.

[0021] In one or more embodiments, the prime mover may be an electric motor.

[0022] When an electric motor is used as a prime mover, it operates quieter than when an internal combustion engine is used as the prime mover, so if loud noise is generated, it will significantly impair user comfort. With the above configuration, it is possible to suppress the generation of loud noise in a blower that uses an electric motor as a prime mover.

[0023] (Example) The blower 2 shown in FIG. 1 includes a housing 4, a fan 6 (see FIG. 2), an electric motor 8 (see FIG. 2), an intake port 10, an exhaust port 12, a nozzle 14, a trigger switch 16, a lock button 18, and a power cord 20. The blower 2 is a handheld implement that can be held in one hand by a user. The nozzle 14 can be selectively attached to or detached from the intake port 10 or the exhaust port 12 depending on the task to be performed by the blower 2. For example, by using the blower 2 with the nozzle 14 attached to the exhaust port 12, the blower 2 can perform a blowing operation in which air is blown out from the tip of the nozzle 14 to blow away fallen leaves, etc. Furthermore, by using the blower 2 with the nozzle 14 attached to the intake port 10 and a dust bag (not shown) attached to the exhaust port 12, the blower 2 can perform a suction operation in which air is sucked in from the tip of the nozzle 14 to collect dust, etc., in the dust bag. In the following description, the direction in which air flows through the exhaust port 12 is referred to as the forward direction, and the opposite direction to the forward direction is referred to as the backward direction. The direction in which air flows through the intake port 10 is referred to as the rightward direction, and the opposite direction to the rightward direction is referred to as the leftward direction. Furthermore, the direction perpendicular to the front-rear direction and the left-right direction is referred to as the up-down direction.

[0024] As shown in FIG. 2, the housing 4 includes a handle 22 that can be held by a user, a fan case 24 that houses the fan 6, and a motor case 26 that houses the electric motor 8. The trigger switch 16 and the lock button 18 are provided on the handle 22. A power cord 20 (see FIG. 3) is also connected to the handle 22. When the user pulls in the trigger switch 16 to turn it on, power is supplied from the power cord 20 to the electric motor 8, causing the fan 6 to rotate. At this time, the rotation speed of the electric motor 8 varies depending on the amount the trigger switch 16 is pulled in. When the user releases the trigger switch 16 to turn it off, the power supply from the power cord 20 to the electric motor 8 is cut off, causing the fan 6 to stop rotating. If the user further presses the lock button 18 while the trigger switch 16 is pulled in, the trigger switch 16 remains pulled in even if the user subsequently releases the lock button 18 or the trigger switch 16. In this case, the electric motor 8 continues to rotate at the desired rotation speed.

[0025] Air intake 10 communicates between the outside and the inside of fan case 24. Air intake 10 is formed with a cylindrical nozzle receiving portion 10a that protrudes toward the left, and a filter portion 10b that prevents foreign matter from entering fan case 24 through air intake 10. Air intake 10 is disposed approximately coaxially with the rotation axis of fan 6 inside fan case 24. Fan case 24 and motor case 26 communicate with each other via motor exhaust port 28. In addition, a motor air intake (not shown) that communicates between the outside and the inside of motor case 26 is formed at the right end of motor case 26.

[0026] The fan 6 includes a base 6a having a circular, flat plate shape, a first fan 6b protruding leftward from the left surface of the base 6a, and a second fan 6c protruding rightward from the right surface of the base 6a. Both the first fan 6b and the second fan 6c function as centrifugal fans. As shown in FIG. 3, the fan case 24 includes a volute portion 24a having a volute shape and a straight pipe portion 24b having a straight pipe shape. As shown in FIG. 2, when the fan 6 rotates, the first fan 6b draws air from the intake port 10 into the volute portion 24a of the fan case 24 and pushes air from the radially inner side of the first fan 6b toward the radially outer side. When the fan 6 rotates, the second fan 6c draws air from the motor exhaust port 28 into the volute portion 24a of the fan case 24 and pushes air from the radially inner side of the second fan 6c toward the radially outer side. At this time, air is drawn into motor case 26 through the motor intake port, and the air inside motor case 26 flows into fan case 24 through motor exhaust port 28, so that electric motor 8 is cooled by the air flow inside motor case 26. As shown in Figure 3, air pushed from the radially inner side to the radially outer side by the rotation of first fan 6b and second fan 6c flows along the radially outer inner surface of volute portion 24a, passes through straight pipe portion 24b, and is then sent out forward from exhaust port 12.

[0027] As shown in FIG. 2, the housing 4 includes a left housing 30 that defines the left side of the fan case 24, an intermediate housing 32 that defines the right side of the fan case 24 and the left side of the motor case 26, a right housing 34 that defines the right side of the motor case 26 and the right side of the handle 22, and a handle housing 36 that defines the left side of the handle 22.

[0028] As shown in FIG. 4, the exhaust port 12 is located at the downstream end (i.e., the front end) of the straight pipe portion 24b. The exhaust port 12 includes a cylindrical nozzle receiving portion 12a that protrudes forward and a filter portion 12b that prevents foreign matter from entering the fan case 24 through the exhaust port 12. In this embodiment, the filter portion 12b is made up of a plurality of plate portions 38. Each of the plate portions 38 has a generally flat plate shape extending in the front-rear and left-right directions. The plate portions 38 include a first right plate portion 38a, a first left plate portion 38b, a second right plate portion 38c, a second left plate portion 38d, a third right plate portion 38e, and a third left plate portion 38f. The first right plate portion 38a, the second right plate portion 38c, and the third right plate portion 38e are seamlessly and integrally formed with the intermediate housing 32 and extend leftward from the inner surface of the intermediate housing 32. The second right-side plate portion 38c is disposed below the first right-side plate portion 38a, and the third right-side plate portion 38e is disposed below the second right-side plate portion 38c. The first left-side plate portion 38b, the second left-side plate portion 38d, and the third left-side plate portion 38f are formed seamlessly and integrally with the left-side housing 30, and extend rightward from the inner surface of the left-side housing 30. The second left-side plate portion 38d is disposed below the first left-side plate portion 38b, and the third left-side plate portion 38f is disposed below the second left-side plate portion 38d.

[0029] As shown in Fig. 5, the first right-side plate portion 38a and the first left-side plate portion 38b are positioned approximately the same in the vertical direction. The vertical distance D1 from the top of the inner surface of the exhaust port 12 to the upper surface of the first right-side plate portion 38a (or the upper surface of the first left-side plate portion 38b) is within a range of 2 mm to 12 mm, for example, 11 mm. The first right-side plate portion 38a and the first left-side plate portion 38b have approximately the same plate thickness in the vertical direction. The vertical plate thickness T1 of the first right-side plate portion 38a (or the first left-side plate portion 38b) is within a range of 0.1 mm to 5 mm, for example, 1.5 mm. The right end of the first right-side plate portion 38a and the left end of the first left-side plate portion 38b abut against each other.

[0030] The second right plate portion 38c and the second left plate portion 38d are positioned approximately the same in the vertical direction. The vertical distance D2 from the lower surface of the first right plate portion 38a (or the lower surface of the first left plate portion 38b) to the upper surface of the second right plate portion 38c (or the upper surface of the second left plate portion 38d) is within a range of 2 mm to 12 mm, for example, 11.5 mm. The second right plate portion 38c and the second left plate portion 38d have approximately the same plate thickness in the vertical direction. The vertical thickness T2 of the second right plate portion 38c (or the second left plate portion 38d) is within a range of 0.1 mm to 5 mm, for example, 1.5 mm. In this embodiment, the vertical thickness T2 of the second right plate portion 38c (or the second left plate portion 38d) is approximately the same as the vertical thickness T1 of the first right plate portion 38a (or the first left plate portion 38b). The right end of the second right plate portion 38c and the left end of the second left plate portion 38d abut against each other.

[0031] The third right plate portion 38e and the third left plate portion 38f are positioned approximately the same in the vertical direction. The vertical distance D3 from the lower surface of the second right plate portion 38c (or the lower surface of the second left plate portion 38d) to the upper surface of the third right plate portion 38e (or the upper surface of the third left plate portion 38f) is within a range of 2 mm to 12 mm, for example, 6 mm. The vertical distance D4 from the lower surface of the third right plate portion 38e (or the lower surface of the third left plate portion 38f) to the lowest part of the inner surface of the exhaust port 12 is within a range of 2 mm to 12 mm, for example, 6 mm. The third right plate portion 38e and the third left plate portion 38f have approximately the same plate thickness in the vertical direction. The vertical plate thickness T3 of the third right plate portion 38e (or the third left plate portion 38f) is within a range of 0.5 mm to 5 mm, for example, 1.5 mm. In this embodiment, the vertical thickness T3 of the third right plate portion 38e (or the third left plate portion 38f) is approximately equal to the vertical thickness T2 of the second right plate portion 38c (or the second left plate portion 38d). The right end of the third right plate portion 38e and the left end of the third left plate portion 38f abut against each other.

[0032] 4, the first right plate portion 38a, the second right plate portion 38c, and the third right plate portion 38e have a generally right-angled trapezoidal shape when viewed in a plan view from above, with the front side being generally perpendicular to the right and left sides and the right side being longer than the left side. The first left plate portion 38b, the second left plate portion 38d, and the third left plate portion 38f have a generally right-angled trapezoidal shape when viewed in a plan view from above, with the front side being generally perpendicular to the right and left sides and the left side being longer than the right side.

[0033] As shown in FIG. 6, when the first right-side plate portion 38a (or the first left-side plate portion 38b) is viewed in plan from above, the distance L in the front-rear direction from an intersection C of an imaginary line extending from the rear side and an imaginary line extending from the left side (or the right side) to the front side is within a range of 1 mm to 50 mm, for example, 13 mm. When the first right-side plate portion 38a (or the first left-side plate portion 38b) is viewed in plan from above, the angle θ formed between the rear side and the left side (or the right side) is within a range of 0.1 degrees to 90 degrees, for example, 45 degrees. The second right-side plate portion 38c (or the second left-side plate portion 38d) and the third right-side plate portion 38e (or the third left-side plate portion 38f) also have similar characteristics.

[0034] As shown in FIG. 4, a plurality of protrusions 40 are formed on at least some of the plurality of plate portions 38. For example, a first upper right protrusion 40a is formed on the upper surface of the first right plate portion 38a, protruding upward from near the front end of the first right plate portion 38a and extending in the left-right direction. A first upper left protrusion 40b is formed on the upper surface of the first left plate portion 38b, protruding upward from near the front end of the first left plate portion 38b and extending in the left-right direction. As shown in FIG. 5, the first upper right protrusion 40a and the first upper left protrusion 40b have approximately the same height in the up-down direction. The height H of the first upper right protrusion 40a (or the first upper left protrusion 40b) in the up-down direction is within a range of 0.15 mm to 1.5 mm, e.g., 0.5 mm. As shown in FIG. 6, the first upper right protrusion 40a and the first upper left protrusion 40b have approximately the same width in the front-to-rear direction. The width W in the front-rear direction of the first upper right protrusion 40a (or the first upper left protrusion 40b) is within a range of 0.5 mm to 10 mm, and is, for example, 2 mm.

[0035] In this embodiment, the first upper right protrusion 40a extends continuously in the left-right direction on the upper surface of the first right plate portion 38a. Therefore, when manufacturing the intermediate housing 32 by integral molding of a resin material, the first right plate portion 38a and the mold that defines the shape of the first upper right protrusion 40a can be removed by linearly moving them in the left direction. Furthermore, the first upper left protrusion 40b extends continuously in the left-right direction on the upper surface of the first left plate portion 38b. Therefore, when manufacturing the left housing 30 by integral molding of a resin material, the first left plate portion 38b and the mold that defines the shape of the first upper left protrusion 40b can be removed by linearly moving them in the right direction.

[0036] FIG. 7 is a graph showing the effect of the presence or absence of the first upper-right protrusion 40a and the first upper-left protrusion 40b on the noise level of the blower 2 during operation. The graph labeled "No Countermeasure" in FIG. 7 shows the noise level of the blower 2 during operation when the first upper-right protrusion 40a and the first upper-left protrusion 40b are not provided. As can be seen from FIG. 7, in this case, the noise level of the blower 2 during operation becomes particularly high at a certain motor rotation speed. This is because, without the first upper-right protrusion 40a or the first upper-left protrusion 40b, vortices are periodically generated at the front ends of the first right plate portion 38a and the first left plate portion 38b. At a certain motor rotation speed, the frequency at which these vortices are generated coincides with the resonant frequency of the plurality of plate portions 38 and the straight pipe portion 24b, causing the plurality of plate portions 38 and the straight pipe portion 24b to resonate.

[0037] In contrast, the graph labeled "With Countermeasures" in Figure 7 shows noise levels during use of the blower 2 when the first upper-right protrusion 40a and the first upper-left protrusion 40b are present. As can be seen from Figure 7, in this case, the noise level during use of the blower 2 does not become particularly high at a specific motor rotation speed. This is thought to be because the first upper-right protrusion 40a and the first upper-left protrusion 40b suppress the generation of periodic vortex flows at the front ends of the first right plate portion 38a and the first left plate portion 38b, thereby suppressing resonance of the multiple plate portions 38 and the straight pipe portion 24b or the straight pipe portion 24b itself.

[0038] (Variation) The first right plate portion 38a, the second right plate portion 38c, and the third right plate portion 38e may be separate members from the intermediate housing 32 and may be fixed to the intermediate housing 32, for example, by fasteners or adhesive. The first left plate portion 38b, the second left plate portion 38d, and the third left plate portion 38f may be separate members from the left housing 30 and may be fixed to the intermediate housing 32, for example, by fasteners or adhesive. The first right plate portion 38a, the first left plate portion 38b, the second right plate portion 38c, the second left plate portion 38d, the third right plate portion 38e, and the third left plate portion 38f may each have a shape different from that of the above embodiment. The right end of the first right plate portion 38a and the left end of the first left plate portion 38b do not have to abut against each other. The right end of the second right plate portion 38c and the left end of the second left plate portion 38d do not have to abut on each other. The right end of the third right plate portion 38e and the left end of the third left plate portion 38f do not have to abut on each other.

[0039] The first upper right protrusion 40a may be a separate member from the first right plate portion 38a and may be secured to the first right plate portion 38a by, for example, a fastener or adhesive. The first upper left protrusion 40b may be a separate member from the first left plate portion 38b and may be secured to the first left plate portion 38b by, for example, a fastener or adhesive.

[0040] The first upper right protrusion 40a (or the first upper left protrusion 40b) may be positioned away from the front end of the first right plate portion 38a (or the first left plate portion 38b), for example, within a range up to a position a predetermined distance (e.g., 5 mm) away from the front end in the front-rear direction. Furthermore, when the first right plate portion 38a (or the first left plate portion 38b) is viewed in a plan view from above, the direction in which the first upper right protrusion 40a (or the first upper left protrusion 40b) extends may be inclined with respect to the left-right direction.

[0041] As shown in FIG. 8, the first upper right protrusion 40a and the first upper left protrusion 40b do not have to be formed continuously in the left-right direction, but may be formed discretely in the left-right direction.

[0042] As shown in Fig. 9, protrusions 40 may be formed on plate portions 38 other than the first right plate portion 38a and the first left plate portion 38b. In the example shown in Fig. 9, in addition to the example shown in Fig. 5, a second upper right protrusion 40c is formed on the upper surface of the second right plate portion 38c, and a second upper left protrusion 40d is formed on the upper surface of the second left plate portion 38d. The positions and / or shapes of the second upper right protrusion 40c and the second upper left protrusion 40d may be substantially the same as or different from the positions and / or shapes of the first upper right protrusion 40a and the first upper left protrusion 40b.

[0043] As shown in FIG. 10 , protrusions 40 may be formed on the lower surfaces of the plate portions 38. In the example shown in FIG. 10 , in addition to the example shown in FIG. 9 , a third upper right protrusion 40e is formed on the upper surface of the third right plate portion 38e, and a third upper left protrusion 40f is formed on the upper surface of the third left plate portion 38f. Furthermore, a first lower right protrusion 40g is formed on the lower surface of the first right plate portion 38a, and a first lower left protrusion 40h is formed on the lower surface of the first left plate portion 38b. A second lower right protrusion 40i is formed on the lower surface of the second right plate portion 38c, and a second lower left protrusion 40j is formed on the lower surface of the second left plate portion 38d. A third lower right protrusion 40k is formed on the lower surface of the third right plate portion 38e, and a third lower left protrusion 40l is formed on the lower surface of the third left plate portion 38f.

[0044] The number of the plurality of plate portions 38 may be greater or less than that in the above embodiment.

[0045] The blower 2 may be provided with an axial flow fan (not shown) or a mixed flow fan (not shown) instead of the fan 6.

[0046] The blower 2 may include an internal combustion engine (not shown) instead of the electric motor 8 as a prime mover for rotating the fan 6. Alternatively, the blower 2 may include another type of electric motor (not shown), such as a brushless motor, instead of the electric motor 8.

[0047] The blower 2 may be provided with a battery attachment portion (not shown) to which a rechargeable battery pack (not shown) can be attached and detached, instead of the power cord 20. In this case, the electric motor 8 may be operated by power supplied from the battery pack.

[0048] (Features of the embodiment) As described above, in one or more embodiments, the blower 2 comprises an electric motor 8 (an example of a prime mover), a fan 6 driven by the electric motor 8, a straight pipe section 24b (an example of an air duct) through which the airflow generated by the fan 6 flows, a plate section 38 arranged inside the straight pipe section 24b and having a side along the direction in which the airflow flows, and a protrusion 40 protruding from the side near the downstream end of the plate section 38 in a direction that blocks the airflow.

[0049] According to the above configuration, the protrusion 40 is provided near the downstream end of the plate portion 38, which makes it possible to suppress the generation of periodic vortex flows at the downstream end of the plate portion 38. This makes it possible to suppress the generation of large noise due to resonance of the plate portion 38 and the straight pipe portion 24b, and resonance of the straight pipe portion 24b.

[0050] In one or more embodiments, the height of the protrusion 40 in the direction of blocking the airflow is within the range of 1% to 50% of the thickness of the plate portion 38 .

[0051] According to the above configuration, the generation of periodic vortex flows can be suppressed without significantly affecting the airflow volume of the blower 2.

[0052] In one or more embodiments, the width of the protrusion 40 in the direction of airflow is within the range of 1% to 50% of the minimum width of the plate portion 38 .

[0053] According to the above configuration, the generation of periodic vortex flows can be suppressed without significantly affecting the airflow volume of the blower 2.

[0054] In one or more embodiments, the protrusions 40 are discrete.

[0055] According to the above configuration, the influence on the air flow rate of the blower 2 can be made smaller than when the protruding portion 40 is provided continuously.

[0056] In one or more embodiments, the protrusions 40 may be continuous.

[0057] According to the above configuration, when the plate portion 38 provided with the protrusions 40 is manufactured by integral molding of a resin material, the workability of the die-cutting process can be improved.

[0058] In one or more embodiments, the protrusion 40 is provided on only one side (e.g., the top surface) of the plate portion 38, and the protrusion 40 is not provided on the other side (e.g., the bottom surface) of the plate portion 38.

[0059] According to the above configuration, the effect on the air flow rate of the blower 2 can be made smaller than when the protrusions 40 are provided on both side surfaces of the plate portion 38.

[0060] In one or more embodiments, the electric motor 8 serves as a prime mover to drive the fan 6 .

[0061] When an electric motor 8 is used as a prime mover, it operates quieter than when an internal combustion engine (not shown) is used as the prime mover, and therefore, if loud noise is generated, it will significantly impair user comfort. With the above configuration, it is possible to suppress the generation of loud noise in a blower 2 that uses an electric motor 8 as a prime mover. [Explanation of symbols]

[0062] 2: Blower 4: Housing 6: Fan 6a: Bass 6b: First fan 6c: Second fan 8: Electric motor 10: Air intake 10a: Nozzle receiving part 10b: Filter section 12: Exhaust port 12a: Nozzle receiving part 12b: Filter section 14: Nozzle 16: Trigger switch 18: Lock button 20: Power cord 22: Handle 24: Fan case 24a: Volute section 24b: Straight pipe section 26: Motor case 28: Motor exhaust port 30: Left housing 32: Intermediate housing 34: Right housing 36: Handle housing 38: Plate section 38a: First right plate part 38b: First left plate part 38c: Second right plate part 38d: Second left plate part 38e: Third right plate part 38f: Third left plate section 40:Protrusion 40a: 1st upper right protrusion 40b: 1st upper left protrusion 40c: 2nd upper right protrusion 40d: 2nd upper left protrusion 40e: Third upper right protrusion 40f: 3rd upper left protrusion 40g: The first protrusion on the lower right side 40h: First lower left protrusion 40i: Second lower right protrusion 40j: Second lower left protrusion 40k: The third right lower protrusion 40l: The third lower left protrusion

Claims

1. A blower, The prime mover and a fan driven by the prime mover; an air duct through which the airflow generated by the fan flows; a plate portion disposed inside the air duct and having a side surface along the direction in which the air flows; a protrusion protruding from the side surface near the downstream end of the plate portion in a direction that blocks the airflow.

2. 2. The blower according to claim 1, wherein the height of the protrusion in the direction in which the airflow is blocked is within a range of 1% to 50% of the thickness of the plate portion.

3. 3. The blower of claim 1, wherein the width of the protrusion is within a range of 1% to 50% of the minimum width of the plate portion relative to the direction of airflow.

4. The blower according to claim 1 , wherein the protrusions are provided discretely.

5. 4. The blower according to claim 1, wherein the protrusion is provided continuously.

6. The blower according to claim 1 , wherein the protrusion is provided on only one of the side surfaces of the plate portion, and the protrusion is not provided on the other side surface of the plate portion.

7. 7. A blower according to any one of claims 1 to 6, wherein the prime mover is an electric motor.

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