blower

Abstract

To provide a technology capable of dispensing with a cooling air passage disposed independently from a ventilation passage, simplifying a structure of a blower, and further miniaturizing the blower.SOLUTION: A blower includes: an intake port; an exhaust port; a blast pipe disposed between the intake port and the exhaust port; a fan disposed inside of the blast pipe; an electric motor disposed inside of the blast pipe, and rotating and driving the fan; a motor housing disposed inside of the blast pipe and housing the electric motor; and a control unit for controlling the electric motor. The control unit includes a control board for controlling driving of the electric motor, and a casing for housing the control board. The blast pipe is provided with an exposure hole radially communicating the inside and the outside of the blast pipe. The casing is disposed on the blast pipe in a manner of covering the whole of the exposure hole from a radial outer side by at least a part of the casing.SELECTED DRAWING: Figure 8

Description

[Technical Field]

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

[0002] Patent Document 1 discloses a blower including an air intake port, an exhaust port, an air duct provided between the air intake port and the exhaust port, a fan disposed inside the air duct, an electric motor disposed inside the air duct for driving the fan, a motor housing disposed inside the air duct for accommodating the electric motor, and a control unit for controlling the electric motor. The control unit includes a control board for controlling the operation of the electric motor and a casing for accommodating the control board. The air duct is provided with a cooling air passage that connects the inside and outside of the air duct. The control unit is disposed inside the cooling air passage without blocking the entire cooling air passage. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-076355 Summary of the Invention [Problem to be solved by the invention]

[0004] In a blower equipped with a control unit, the control unit needs to be cooled to suppress a temperature rise in the control unit due to heat generated by the control board. The blower of Patent Document 1 has a cooling air path separate from the air flow path to cool the control unit. In this case, providing a cooling air path may complicate the blower's structure and increase its size. This specification provides a technology that eliminates the need to provide a cooling air path separate from the air flow path, thereby simplifying the blower's structure and enabling a more compact blower. In this specification, the term "air flow path" refers to a path formed inside the air flow duct, extending from one end of the air flow duct to the other end of the air flow duct. The term "working air" refers to air discharged from an outlet along the air flow path. [Means for solving the problem]

[0005] The blower disclosed in this specification includes an intake port, an exhaust port, an air duct provided between the intake port and the exhaust port, a fan disposed inside the air duct, an electric motor disposed inside the air duct and driving the fan, a motor housing disposed inside the air duct and accommodating the electric motor, and a control unit for controlling the electric motor. The control unit includes a control board that controls the driving of the electric motor and a casing that accommodates the control board. The air duct has an exposure hole that radially communicates the inside and outside of the air duct. The casing is attached to the air duct so that at least a portion of the casing completely blocks the exposure hole from the radial outside.

[0006] According to the above configuration, the casing is attached to the air duct so as to completely cover the exposure hole. At least a portion of the casing is exposed to the air flow path through the exposure hole provided in the air duct. Therefore, the air flowing along the air flow path cools the control unit and is entirely discharged as working air. According to the above configuration, there is no need to provide a cooling air path for cooling the control unit separately from the air flow path, which simplifies the structure of the blower and allows for a smaller blower. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is an overall perspective view of a blower 10 according to an embodiment, seen from above and rear right. [Figure 2] 1 is an exploded view of the internal structure of a blower body 13 of a blower 10 according to an embodiment, seen from the upper rear right side. [Figure 3] 1 is an exploded view showing a blower unit 50 and a control unit 80 provided in a first blower duct 210 of a blower 10 according to an embodiment, and components of the blower unit 50. FIG. [Figure 4] 1 is a cross-sectional view showing the internal structure of a first blower duct 210, a blower unit 50, and a control unit 80 in a blower 10 according to an embodiment. [Figure 5] 3 is a cross-sectional view showing components of a control unit 80 provided in the blower 10 according to the embodiment. FIG. [Figure 6] This figure shows the positional relationship between the electric motor 54, multiple switching elements 84, heat dissipation material 86, mounting portion 212, and exposure hole 216 when viewing the first air duct 210 of the blower 10 of the embodiment from the radially outer side along the vertical direction. [Figure 7] 10 is a cross-sectional view showing the positional relationship between an imaginary plane V extending along the inner surface of a first blower duct 210 and the lower surface of a controller casing 88 in a blower 10 according to the embodiment. FIG. [Figure 8] 1 is a diagram showing an air flow path R1 formed inside a first air flow duct 210 and a circulation path R2 formed in a blower unit 50 in a blower 10 according to the embodiment. [Figure 9] 10 is a diagram showing a schematic diagram of a state in which, when air flows along the airflow path R1 in the blower 10 according to the embodiment, a negative pressure is generated that draws air from the circulation path R2 into the airflow path R1. FIG. [Figure 10] A cross-sectional view showing the first outer diameter φ1 of the exhaust port side end 620 of the hub 62, the second outer diameter φ2 of the intake port side end 560 of the motor housing 56, and the first inner diameter φ3 of the first air duct 210 in the blower 10 of the embodiment. [Figure 11] 1 is a graph showing the relationship between the ratio φ1 / φ2 of the first outer diameter φ1 to the second outer diameter φ2 and the respective rates of change of the cooling air volume and the working air volume when the fan 52 is rotated at a constant rotation speed in a blower 10 according to an embodiment. [Figure 12] 10 is a cross-sectional view showing a second inner diameter φ4 of a first ventilation port 58b in the blower 10 according to the embodiment. FIG. [Figure 13] 10 is a cross-sectional view showing the internal structure of a first blower duct 210, a blower unit 50, and a control unit 80 in a blower 10 according to a modified example. [Figure 14] FIG. 10 is a diagram schematically illustrating a state in which, when air flows along airflow path R1 in a blower 10 according to a modified example, a negative pressure is generated that draws air from circulation path R2 to airflow path R1. 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.

[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 air duct and the motor housing are made of resin, and the at least part of the casing may be made of metal.

[0012] To efficiently cool the control unit, it is desirable to use a material with excellent thermal conductivity for the portion of the casing that houses the control board and that is exposed to the airflow path. On the other hand, to reduce the mass of the entire blower, it is desirable to use a material with low mass for the airflow path and motor housing. With the above configuration, at least the portion of the casing that is exposed to the airflow path is made of metal with excellent thermal conductivity. The airflow path and motor housing are made of resin with low mass. This allows the control unit to be efficiently cooled, while also achieving a lightweight blower overall.

[0013] In one or more embodiments, the at least part of the casing may be disposed radially outward of an imaginary plane extending along the inner surface of the air duct in a portion where the exposure hole is provided. Here, if the inner surface of the air duct is a cylindrical surface, the "imaginary plane" refers to a plane extending along the cylindrical surface.

[0014] If the casing is disposed radially inward of the air duct relative to the imaginary plane, the air flow path will be narrowed where the casing is disposed, which may increase pressure loss in the air flow path. With the above configuration, the air flow path will not be narrowed where the casing is disposed. Therefore, it is possible to suppress an increase in pressure loss in the air flow path.

[0015] In one or more embodiments, the distance between the at least part of the casing and the imaginary plane in the radial direction may be in the range of 2 mm-12 mm.

[0016] Generally, the shorter the distance between the casing and the imaginary plane, the more efficiently the control unit can be cooled by the air flowing through the airflow path. With the above configuration, the control unit can be cooled efficiently.

[0017] In one or more embodiments, when the exposure hole is viewed from the radially outer side, the electric motor and the exposure hole may at least partially overlap each other.

[0018] For example, if the electric motor and the exposure hole do not overlap when viewed from the radial outside, the air duct may become excessively long. According to the above configuration, the electric motor and the exposure hole are arranged so as to at least partially overlap when viewed from the radial outside, so the air duct can be shortened.

[0019] In one or more embodiments, the fan may be an axial fan whose airflow direction coincides with the direction of the fan's rotational axis. The fan may be disposed so that the rotational axis direction is aligned with the extension direction of the air duct. The control board may be configured to control the driving of the electric motor so that the upstream side of the fan's airflow direction corresponds to the intake port side and the downstream side of the fan's airflow direction corresponds to the exhaust port side. The exposure hole may be provided downstream of the fan.

[0020] Typically, the flow velocity of air flowing through the airflow path is faster downstream of the axial fan than upstream. With the above configuration, the control unit casing is exposed to the airflow path downstream of the axial fan. Therefore, air flows at a relatively high velocity where the control unit is exposed to the airflow path. With the above configuration, the control unit can be efficiently cooled.

[0021] In one or more embodiments, the electric motor may be a brushless motor, and the control board may include a plurality of switching elements for switching the current supplied to the electric motor.

[0022] Generally, when the electric motor is a brushless motor, the control board is provided with multiple switching elements for controlling the current supplied to the brushless motor. In this case, the heat generated by the multiple switching elements causes the control unit to generate a relatively large amount of heat. With the above configuration, in a blower equipped with a brushless motor, the control unit can be efficiently cooled without reducing the volume of working air.

[0023] In one or more embodiments, when the exposure hole is viewed from the radially outer side, the switching elements and the exposure hole may at least partially overlap each other.

[0024] According to the above configuration, the switching elements, which are a relatively large heat generating portion of the control unit, at least partially overlap with the exposure hole in the radial direction of the air duct. Therefore, heat generated by the switching elements is easily transferred to the portion of the casing exposed to the air flow path. Therefore, the temperature rise of the entire control unit can be efficiently suppressed. According to the above configuration, the control unit including the switching elements can be efficiently cooled.

[0025] (Example) As shown in Fig. 1, blower 10 includes a battery device 12, a blower main body 13, and a pair of shoulder straps 16. A user can wear blower 10 on their back by placing shoulder straps 16 over their shoulders. That is, blower 10 of this embodiment is a backpack-type blower. In the following description, the up-down, left-right, and front-to-back directions as seen from the user when the user is wearing blower 10 on their back are referred to as the up-down, left-right, and front-to-back directions of blower 10, respectively.

[0026] (Configuration of battery device 12) The battery device 12 houses a plurality of battery cells (not shown). The battery device 12 is equipped with a charging connector 24 and a discharging cable 26. The discharging cable 26 is connected to the blower body 13. The plurality of battery cells can be charged from an external power source (not shown) by connecting a charging cable (not shown) extending from the external power source to the charging connector 24. The plurality of battery cells can be discharged to the blower body 13 via the discharging cable 26.

[0027] (Configuration of blower body 13) The blower body 13 includes an outer housing 14, an air duct 20, and an operating grip 22. As shown in FIG. 2, the outer housing 14 includes an air intake port 30 on the left side. The air intake port 30 communicates between the inside and outside of the outer housing 14. The outer housing 14 also accommodates a portion of the air duct 20. The outer housing 14 holds the air duct 20 so that a first air duct 210 (described later) extends in the left-right direction.

[0028] (Configuration of air duct 20) The air duct 20 includes a first air duct 210 having a generally cylindrical shape extending in the left-right direction, a second air duct 220 having a generally cylindrical shape that bends from rear to front as it moves from left to right, a third air duct 230 having a bellows shape extending in the front-rear direction, and a fourth air duct 240 having a generally cylindrical shape extending in the front-rear direction. The third air duct 230 is configured to be extendable and retractable. The first air duct 210, the second air duct 220, the third air duct 230, and the fourth air duct 240 are connected in series. The left end of the first air duct 210 faces the air intake port 30 and is connected to the air intake port 30. The front end of the fourth air duct 240 is provided with an exhaust port 32. As described above, the air duct 20 is configured such that one end is connected to the air intake port 30 and the other end functions as the exhaust port 32. In this specification, with respect to the extension direction of the air duct 20, the side facing the intake port 30 may be referred to as the intake port side, and the side facing the exhaust port 32 may be referred to as the exhaust port side. For example, the left side of the first air duct 210 may be referred to as the intake port side, and the right side of the first air duct 210 may be referred to as the exhaust port side.

[0029] (Configuration of the operation grip 22) 1, the operation grip 22 is provided in a position on the fourth air duct 240 where it can be operated by a user by gripping it. The user can adjust the orientation of the fourth air duct 240 while gripping the operation grip 22, thereby adjusting the direction in which the exhaust port 32 is pointed. The operation grip 22 is also provided with a plurality of switches, such as triggers 28, which are operated by the user.

[0030] (Configuration of the blower unit 50) 3, the blower body 13 is disposed inside the air duct 20 and further includes an air blower unit 50 for blowing air from the air intake port 30 through the air duct 20 toward the air exhaust port 32. The air blower unit 50 includes a fan 52, an electric motor 54 that rotates and drives the fan 52, a motor housing 56 that accommodates the electric motor 54, and a diffuser cone 58 connected to the right end of the motor housing 56.

[0031] (Configuration of electric motor 54) The electric motor 54 includes a drive shaft 60 that can rotate around a rotation axis A1 that extends in the left-right direction. In this embodiment, the electric motor 54 is a brushless motor that includes a stator and a rotor (not shown). The drive shaft 60 is fixed to the rotor, and when power is supplied to the electric motor 54, the drive shaft 60 rotates around the rotation axis A1.

[0032] (Fan 52 configuration) As shown in FIG. 4, the fan 52 includes a hub 62 fixed to the drive shaft 60 from the intake port side, and a plurality of blades 64 provided on a first outer surface 62a of the hub 62. The hub 62 is rotatable around a rotation axis A1. The first outer surface 62a is formed in an axisymmetric shape centered on the rotation axis A1 of the drive shaft 60. An exhaust port-side end 620, which is the end of the first outer surface 62a on the exhaust port side, has a first outer diameter φ1 (see FIG. 10). In this embodiment, the fan 52 is an axial fan. For example, when the fan 52 rotates counterclockwise when the blower unit 50 is viewed from the intake port side, the fan 52 generates an airflow along the rotation axis A1 from the intake port side to the exhaust port side (i.e., from left to right in FIG. 4).

[0033] (Configuration of motor housing 56) As shown in FIG. 3 , the motor housing 56 includes a cylindrical portion 66 extending along the rotation axis A1, a bottom portion 68 provided on the exhaust port side of the electric motor 54, and a lid portion 70 provided on the intake port side of the electric motor 54. The motor housing 56 is supported inside the first air duct 210 by multiple support members 72 formed on the cylindrical portion 66. The cylindrical portion 66, the bottom portion 68, the multiple support members 72, and the first air duct 210 are seamlessly formed as a single unit. The lid portion 70 is fixed to the cylindrical portion 66 with screws (not shown). Therefore, the electric motor 54 is housed in the motor housing 56 by inserting the electric motor 54 into the cylindrical portion 66 and then fixing the lid portion 70 to the cylindrical portion 66. In this embodiment, the cylindrical portion 66, the bottom portion 68, the lid portion 70, the multiple support members 72, and the first air duct 210 are made of a resin such as nylon.

[0034] As shown in FIG. 4, the cylindrical portion 66 has an outer surface 66a formed in a substantially cylindrical shape centered on the rotational axis A1 of the drive shaft 60. The lid portion 70 has an outer surface 70a formed in an axisymmetric shape centered on the rotational axis A1. When the lid portion 70 is fixed to the cylindrical portion 66, the outer surface 66a and the outer surface 70a are connected substantially smoothly along the direction of the rotational axis A1. For this reason, in this specification, the outer surface 66a and the outer surface 70a may be collectively referred to as the "second outer surface 56a." Furthermore, an intake port-side end 560, which is the end of the second outer surface 56a on the intake port side, has a second outer diameter φ2 (see FIG. 10). Here, a second vent 62b is provided between the exhaust port-side end 620 of the hub 62 and the intake port-side end 560 of the motor housing 56. The second ventilation opening 62b is provided along the circumferential direction of the rotation axis A1 between the exhaust port side end 620 and the intake port side end 560. The second ventilation opening 62b has a width in the axial direction of the rotation axis A1. As described above, the second ventilation opening 62b is formed with the exhaust port side end 620 and the intake port side end 560 as its circumferential ends. The second ventilation opening 62b also communicates with the interior of the hub 62 and a ventilation path R1 (see FIG. 8), which will be described later.

[0035] The bottom portion 68 has a first communication hole 68b arranged between the electric motor 54 and the diffuser cone 58 in the direction of the rotation axis A1. The first communication hole 68b connects the interior of the motor housing 56 with the interior of the diffuser cone 58. In this embodiment, a plurality of first communication holes 68b are provided in the circumferential direction at predetermined angular intervals (for example, 60° intervals). The lid portion 70 has a second communication hole 70b arranged between the hub 62 and the electric motor 54 in the direction of the rotation axis A1. The second communication hole 70b connects the interior of the hub 62 with the interior of the motor housing 56. In this embodiment, a plurality of second communication holes 70b are provided in the circumferential direction at predetermined angular intervals (for example, 40° intervals).

[0036] (Diffuser cone 58 configuration) The diffuser cone 58 is connected to the exhaust port side of the cylindrical portion 66 of the motor housing 56 and extends along the rotation axis A1. A portion of the diffuser cone 58 extends toward the exhaust port side beyond the right end of the first air duct 210. That is, the diffuser cone 58 extends across the first air duct 210 and the second air duct 220. The diffuser cone 58 also has a third outer surface 58a formed in an axisymmetric shape centered on the rotation axis A1. The third outer surface 58a smoothly connects to the second outer surface 56a along the rotation axis A1. The diameter of the third outer surface 58a decreases from the intake port side toward the exhaust port side along the rotation axis A1. The diffuser cone 58 has a substantially circular first vent hole 58b whose periphery is the end of the third outer surface 58a on the exhaust port side. The first vent hole 58b opens along the rotation axis A1. First ventilation port 58b has a second inner diameter φ4 (see FIG. 12). First ventilation port 58b communicates the inside of diffuser cone 58 with air flow path R1 (see FIG. 8), which will be described later.

[0037] (Configuration of control unit 80) As shown in FIG. 3 , the blower body 13 further includes a control unit 80 for controlling the electric motor 54 of the blower unit 50. The control unit 80 is mounted on a mounting portion 212 provided on an upper portion of the first air duct 210. The control unit 80 is fixed to the first air duct 210 by the mounting portion 212 and a cover member 214 screwed to the mounting portion 212. The control unit 80 is electrically connected to the battery device 12 (see FIG. 1 ), the trigger 28 (see FIG. 1 ), and the electric motor 54. When the user operates the trigger 28, the control unit 80 adjusts the power supplied from the battery device 12 and supplies it to the electric motor 54, thereby driving the electric motor 54. In this embodiment, the control unit 80 is configured to control the driving of the electric motor 54 so that the fan 52 generates an airflow along the rotation axis A1 from the air intake side to the air exhaust side.

[0038] As shown in FIG. 5 , the control unit 80 includes a control board 82, multiple switching elements 84 provided on the upper surface of the control board 82, a heat dissipation material 86 provided in close contact with the lower surface of the control board 82, a controller casing 88 that houses the control board 82, the multiple switching elements 84, and the heat dissipation material 86, and a potting resin 90 that seals the control board 82, the multiple switching elements 84, and the heat dissipation material 86. The heat dissipation material 86 is also provided in close contact with the upper surface of the controller casing 88. The controller casing 88 includes multiple fins 92 on a portion of its lower surface. The multiple switching elements 84 are disposed above the portion of the controller casing 88 where the multiple fins 92 are provided. In this embodiment, the heat dissipation material 86 is made of a sheet-like aluminum alloy. In this embodiment, the controller casing 88 is made of a metal such as aluminum. In this embodiment, the multiple switching elements 84 are field-effect transistors (FETs) that form an inverter circuit. Therefore, the control unit 80 can convert DC power supplied from the battery device 12 (see FIG. 1) into three-phase AC power and supply it to the electric motor .

[0039] As shown in Fig. 4, an exposure hole 216 that connects the inside and outside of the first air duct 210 in the radial direction of the first air duct 210 is provided in the upper part of the first air duct 210. The exposure hole 216 is provided closer to the exhaust port side than the fan 52. The control unit 80 is attached to the first air duct 210 so that a part of the controller casing 88 completely blocks the exposure hole 216 from the radial outside of the first air duct 210. When the control unit 80 is attached to the first air duct 210, a part of the underside of the controller casing 88 where a plurality of fins 92 are provided (see Fig. 5) is exposed to an air flow path R1 (see Fig. 8) described later.

[0040] As shown in Fig. 6, in this embodiment, when the exposure hole 216 is viewed from the radially outer side of the first air duct 210 in the up-down direction, a part of the electric motor 54, the multiple switching elements 84, and the heat dissipation material 86 are arranged so as to overlap with the exposure hole 216. Note that, for ease of explanation, components other than the electric motor 54, the multiple switching elements 84, the heat dissipation material 86, the mounting portion 212 (first air duct 210), and the exposure hole 216 are omitted from Fig. 6.

[0041] 7, the lower surface of the controller casing 88 has a generally flat shape that extends in the front-rear and left-right directions. The lower surface of the controller casing 88 is located radially outward of the first air duct 210 from an imaginary plane V that extends along the inner surface of the first air duct 210 at the portion where the exposure hole 216 is provided. Note that the shortest distance d1 between the lower surface of the controller casing 88 and the imaginary plane V in the radial direction of the first air duct 210 is 2 mm. The longest distance d2 between the lower surface of the controller casing 88 and the imaginary plane V in the radial direction of the first air duct 210 is 12 mm.

[0042] (Air flow path R1) As shown in Fig. 8, an air flow path R1 is formed inside the air duct 20, extending from the left end of the first air duct 210 to the second air duct 220, passing through the outside of the hub 62, the outside of the motor housing 56, and the outside of the diffuser cone 58 in this order. Although not shown, the air flow path R1 reaches the second air duct 220, then passes through the third air duct 230 (see Fig. 2) and the fourth air duct 240 (see Fig. 2), and then reaches the exhaust port 32 (see Fig. 2). In the blower 10 of this embodiment, when the fan 52 generates an air flow from the intake port side to the exhaust port side, the air from the intake port 30 flows through the air flow path R1 toward the exhaust port 32, passing through the outside of the hub 62, the outside of the motor housing 56, and the outside of the diffuser cone 58.

[0043] As described above, the multiple fins 92 (see FIG. 5) of the controller casing 88 that cover the exposure hole 216 are exposed to the airflow path R1. Therefore, the air flowing along the airflow path R1 guides the heat released from the multiple fins 92 exposed to the airflow path R1 to the exhaust port 32. That is, the air flowing along the airflow path R1 is used as cooling air that suppresses a temperature rise in the control unit 80. With the blower 10 of this embodiment, the entire amount of air used as cooling air is discharged from the exhaust port 32. Therefore, with the blower 10 of this embodiment, it is possible to cool the control unit 80 without reducing the volume of working air.

[0044] (Circulation route R2) In the blower unit 50, a circulation path R2 is formed, which runs from the airflow path R1 through the first vent port 58b, the interior of the diffuser cone 58, the first communication hole 68b, the interior of the motor housing 56, the second communication hole 70b, the interior of the hub 62, and the second vent port 62b in this order, and then returns to the airflow path R1. In the circulation path R2, the air flowing through the airflow path R1 flows into the interior of the diffuser cone 58 from the first vent port 58b, passes through the interior of the motor housing 56, and flows out from the second vent port 62b to the airflow path R1.

[0045] As shown in FIG. 9, when air flows along the airflow path R1, the air flowing along the first outer surface 62a separates from the first outer surface 62a at the exhaust port-side end 620, generating a negative pressure in the second air vent 62b that draws air from the circulation path R2 to the airflow path R1. At this time, as shown in FIG. 8, a negative pressure is generated in the first air vent 58b that draws air from the airflow path R1 to the circulation path R2. Thus, when air flows along the airflow path R1, a portion of the air flowing along the airflow path R1 also flows along the circulation path R2. The air flowing along the circulation path R2 guides heat generated in the electric motor 54 housed inside the motor housing 56 to the airflow path R1. In other words, the air flowing along the circulation path R2 is used as cooling air to suppress a rise in temperature of the electric motor 54.

[0046] (Negative pressure increasing mechanism near the second ventilation port 62b) As shown in FIG. 10 , in this embodiment, the first outer diameter φ1 of the exhaust port-side end 620 of the hub 62 is larger than the second outer diameter φ2 of the intake port-side end 560 of the motor housing 56. As described above, the hub 62 and the motor housing 56 each have an axisymmetric shape centered on the rotational axis A1 of the drive shaft 60, and therefore the intake port-side end 560 is offset radially inward from the rotational axis A1 relative to the exhaust port-side end 620. This increases the distance from the point at which air flowing along the first outer surface 62a separates from the first outer surface 62a (i.e., the separation point) to the point at which the separated air reattaches on the second outer surface 56a (i.e., the reattachment point). This increases the negative pressure that generates an airflow in the circulation path R2. Therefore, the blower 10 of this embodiment can increase the volume of cooling air used to cool the electric motor 54.

[0047] (ratio of first outer diameter φ1 to second outer diameter φ2 φ1 / φ2) As shown in FIG. 11 , the flow rate of the cooling air for cooling the electric motor 54 (cooling air flow rate) and the flow rate of the working air vary depending on the ratio φ1 / φ2 of the first outer diameter φ1 to the second outer diameter φ2. The cooling air flow rate monotonically increases when the ratio φ1 / φ2 of the first outer diameter φ1 to the second outer diameter φ2 increases from 100% to 115%, but monotonically decreases when the ratio φ1 / φ2 of the first outer diameter φ1 to the second outer diameter φ2 increases beyond 116%. The flow rate of the working air monotonically decreases as the ratio φ1 / φ2 of the first outer diameter φ1 to the second outer diameter φ2 increases. Therefore, as long as the ratio φ1 / φ2 of the first outer diameter φ1 to the second outer diameter φ2 is within the range of 101% to 116%, the cooling air flow rate can be effectively increased while suppressing a decrease in the flow rate of the working air. In FIG. 11, the rate of change in the cooling airflow and the working airflow when φ1 / φ2 is changed is shown assuming that the rate of change in the airflow when φ1 / φ2 is 100% is 100%.

[0048] In particular, when the ratio φ1 / φ2 of the first outer diameter φ1 to the second outer diameter φ2 increases from 100% to 103%, the gradient of the rate of change (increase) of the cooling airflow is relatively large. Furthermore, the gradient of the rate of change (decrease) of the working airflow is substantially constant regardless of the ratio φ1 / φ2 of the first outer diameter φ1 to the second outer diameter φ2. Therefore, if the ratio φ1 / φ2 of the first outer diameter φ1 to the second outer diameter φ2 is 103%, the cooling airflow can be more effectively increased while further suppressing the decrease in the working airflow. Therefore, in the blower 10 of this embodiment, the ratio φ1 / φ2 of the first outer diameter φ1 to the second outer diameter φ2 is 103%.

[0049] (ratio of first inner diameter φ3 to second outer diameter φ2: φ3 / φ2) As shown in FIG. 10 , the first air duct 210 has a first inner diameter φ3 at the radially outer side of the outlet-side end 620. If the ratio φ3 / φ2 of the first inner diameter φ3 to the second outer diameter φ2 is too small, the air flow path R1 may be narrowed as the first outer diameter φ1 is increased, which may result in a significant increase in pressure loss in the air flow path R1. On the other hand, if the ratio φ3 / φ2 of the first inner diameter φ3 to the second outer diameter φ2 is too large, the air flow generated in the air flow path R1 by driving the fan 52 may be disturbed. In this embodiment, the ratio φ3 / φ2 of the first inner diameter φ3 to the second outer diameter φ2 is 187%. This prevents an increase in pressure loss in the air flow path R1 and also prevents air flow disturbance in the air flow path R1.

[0050] (ratio of second inner diameter φ4 to second outer diameter φ2 φ4 / φ2) Furthermore, if the ratio φ4 / φ2 of the second inner diameter φ4 (see FIG. 12) of the first ventilation port 58b to the second outer diameter φ2 is too small, the amount of air taken in by the first ventilation port 58b into the circulation path R2 may be too small. On the other hand, if the ratio φ4 / φ2 of the second inner diameter φ4 to the second outer diameter φ2 is too large, the amount of air taken in by the first ventilation port 58b into the circulation path R2 may be too large. In this embodiment, the ratio φ4 / φ2 of the second inner diameter φ4 to the second outer diameter φ2 is 33%. Therefore, the amount of air taken in by the first ventilation port 58b into the circulation path R2 can be made appropriate.

[0051] (Variation) In the above embodiment, the blower 10 is a backpack-type blower. In another embodiment, the blower 10 may be a blower other than a backpack-type blower. For example, the blower 10 may be a handheld blower.

[0052] In the above embodiment, the blower 10 includes the battery device 12 connected to the blower body 13 via the discharge cable 26, and power is supplied from the battery device 12 to the electric motor 54. In another embodiment, instead of the battery device 12, the blower 10 may include at least one battery pack (another example of a battery device) that is provided in the blower body 13 and detachably attached to a battery attachment portion (not shown) that has connection terminals. When at least one battery pack is attached to the battery attachment portion, power may be supplied from the at least one battery pack to the electric motor 54. In yet another embodiment, instead of the battery device 12, the blower 10 may include a power cord for connecting the blower body 13 to an external power source, and power may be supplied to the electric motor 54 from the external power source via the power cord.

[0053] In the above embodiment, the air duct 20 is described as including the first air duct 210, the second air duct 220, the third air duct 230, and the fourth air duct 240. In another embodiment, the air duct 20 may not include at least one of the second air duct 220, the third air duct 230, and the fourth air duct 240.

[0054] In the above embodiment, the electric motor 54 is a brushless motor. In another embodiment, the electric motor 54 may be a motor other than a brushless motor. For example, the electric motor 54 may be a motor with brushes.

[0055] In the above embodiment, the fan 52 is an axial fan. In another embodiment, the fan 52 may be a fan other than an axial fan. For example, the fan 52 may be a centrifugal fan such as a sirocco fan.

[0056] In the above embodiment, a configuration has been described in which the hub 62 is fixed to the drive shaft 60. In another embodiment, a reducer (not shown) may be provided between the hub 62 and the drive shaft 60. In this case, the hub 62 may be fixed to an output shaft different from the drive shaft 60, and the output shaft may be connected to the drive shaft 60 via the reducer. In other words, the hub 62 may be provided to be rotatable around a rotation axis different from the rotation axis A1 of the drive shaft 60.

[0057] In the above embodiment, the cylindrical portion 66, the bottom portion 68, the plurality of support members 72, and the first air duct 210 are seamlessly formed as a single unit. In another embodiment, at least one of the cylindrical portion 66, the bottom portion 68, the plurality of support members 72, and the first air duct 210 may be formed as a separate body.

[0058] In the above embodiment, a configuration has been described in which resin such as nylon is used for the cylindrical portion 66, the bottom portion 68, the lid portion 70, the plurality of support members 72, and the first air duct 210. In another embodiment, a material other than resin may be used for at least one of the cylindrical portion 66, the bottom portion 68, the lid portion 70, the plurality of support members 72, and the first air duct 210. For example, aluminum or the like may be used for at least one of the cylindrical portion 66, the bottom portion 68, the lid portion 70, the plurality of support members 72, and the first air duct 210.

[0059] In the above embodiment, an aluminum alloy is used for the heat dissipation material 86. In another embodiment, a material other than an aluminum alloy may be used for the heat dissipation material 86. For example, silicone rubber or the like may be used for the heat dissipation material 86.

[0060] In the above embodiment, a configuration has been described in which a metal such as aluminum is used for the controller casing 88. In another embodiment, a material other than metal may be used for the controller casing 88. For example, the controller casing 88 may be made of nylon or the like.

[0061] In the above embodiment, a configuration has been described in which the exposure hole 216 is provided downstream of the fan 52 (on the exhaust port side), and the controller casing 88 is exposed to the airflow path R1 downstream of the fan 52. In another embodiment, the exposure hole 216 may be provided upstream of the fan 52 (on the intake port side), and the controller casing 88 may be exposed to the airflow path R1 upstream of the fan 52.

[0062] In the above embodiment, a configuration has been described in which the electric motor 54 and the exposure hole 216 partially overlap when the exposure hole 216 is viewed from the radially outside of the first air duct 210. In another embodiment, the electric motor 54 and the exposure hole 216 may not overlap when the exposure hole 216 is viewed from the radially outside of the first air duct 210. In this case, the exposure hole 216 may be located closer to the exhaust port than the electric motor 54, or closer to the intake port than the electric motor 54.

[0063] In the above embodiment, a configuration has been described in which the bottom surface of the controller casing 88 has a substantially flat shape. In another embodiment, the bottom surface of the controller casing 88 does not have to have a substantially flat shape. For example, the bottom surface of the controller casing 88 may have a shape that follows the imaginary plane V.

[0064] In the above embodiment, a configuration has been described in which the lower surface of the controller casing 88 is disposed radially outward from the first air duct 210 relative to the imaginary plane V that extends along the inner surface of the first air duct 210 at the portion where the exposure holes 216 are provided. In another embodiment, the lower surface of the controller casing 88 does not have to be disposed radially outward from the first air duct 210 relative to the imaginary plane V that extends along the inner surface of the first air duct 210 at the portion where the exposure holes 216 are provided. For example, the lower surface of the controller casing 88 may be disposed radially inward from the first air duct 210 relative to the imaginary plane V that extends along the inner surface of the first air duct 210 at the portion where the exposure holes 216 are provided.

[0065] In the above embodiment, a configuration has been described in which the mounting portion 212 and the exposure hole 216 are provided on the upper part of the first air duct 210, and the control unit 80 is attached to the upper part of the first air duct 210. In another embodiment, the mounting portion 212 and the exposure hole 216 may be provided at a position other than the upper part of the first air duct 210, and the control unit 80 may be attached at a position other than the upper part of the first air duct 210. For example, the mounting portion 212 and the exposure hole 216 may be provided at a lower part or the like of the first air duct 210, and the control unit 80 may be attached at a lower part or the like of the first air duct 210.

[0066] In the above embodiment, the multiple switching elements 84 are FETs. In another embodiment, the multiple switching elements 84 may be switching elements other than FETs. For example, the multiple switching elements 84 may be IGBTs (insulated gate bipolar transistors) or the like.

[0067] In the above embodiment, the ratio φ1 / φ2 of the first outer diameter φ1 to the second outer diameter φ2 is 103%. In another embodiment, the ratio φ1 / φ2 of the first outer diameter φ1 to the second outer diameter φ2 may be changed as appropriate within the range of 101% to 116%.

[0068] In the above embodiment, the ratio φ3 / φ2 of the first inner diameter φ3 to the second outer diameter φ2 is 187%. In another embodiment, the ratio φ3 / φ2 of the first inner diameter φ3 to the second outer diameter φ2 may be changed as appropriate within the range of 175% to 195%.

[0069] In the above embodiment, the ratio φ4 / φ2 of the second inner diameter φ4 to the second outer diameter φ2 is 33%. In another embodiment, the ratio φ4 / φ2 of the second inner diameter φ4 to the second outer diameter φ2 may be changed as appropriate within the range of 15% to 50%.

[0070] 13 , in another embodiment, the blower 10 may include a second air duct 320 instead of the second air duct 220, and may include a diffuser cone 158 instead of the diffuser cone 58. The second air duct 320 has a shape that curves from top to bottom as it moves from left to right. The diffuser cone 158 has a shape that curves from top to bottom as it moves from left to right, following the curved shape of the second air duct 320. In this case, the first air opening 58b opens along the extension direction of the second air duct 320.

[0071] As shown in FIG. 14 , in another embodiment, a disk-shaped plate member 100 may be disposed between the hub 62 and the motor housing 56. The plate member 100 may have an outer surface 100a that is axially symmetrical about the rotation axis A1. The plate member 100 may be fixed to the drive shaft 60 (see FIG. 4 ) separately from the hub 62. Furthermore, instead of forming the second vent 62b with the exhaust port-side end 620 of the hub 62 and the intake port-side end 560 of the motor housing 56 as peripheral ends, the second vent 62b may be formed with the exhaust port-side end 102 and the intake port-side end 560, which are the exhaust port-side ends of the outer surface 100a of the plate member 100. Although not shown, the outer diameter of the exhaust port-side end 102 may be larger than the second outer diameter φ2 of the intake port-side end 560. In this case, the first outer diameter φ1 of the exhaust port-side end 620 may be equal to or smaller than the second outer diameter φ2 of the intake port-side end 560. In this case, the plate member 100 increases the negative pressure that generates an air flow in the circulation path R2. That is, the plate member 100 increases the amount of cooling air for cooling the electric motor .

[0072] (Correspondence) As described above, in one or more embodiments, the blower 10 includes the intake port 30, the exhaust port 32, the air duct 20 (specifically, the first air duct 210) provided between the intake port 30 and the exhaust port 32, the fan 52 disposed inside the air duct 20, the electric motor 54 disposed inside the air duct 20 for driving and rotating the fan 52, the motor housing 56 disposed inside the air duct 20 for accommodating the electric motor 54, and the control unit 80 for controlling the electric motor 54. The control unit 80 includes a control board 82 for controlling the drive of the electric motor 54, and a controller casing 88 (an example of a casing) for accommodating the control board 82. The air duct 20 is provided with an exposure hole 216 that radially communicates the inside and outside of the air duct 20. The controller casing 88 is attached to the air duct 20 so that a part of the controller casing 88 (an example of at least a part of the casing) covers the entire exposure hole 216 from the radially outer side.

[0073] According to the above configuration, controller casing 88 is attached to air duct 20 so as to completely block exposure hole 216. At this time, a portion of controller casing 88 is exposed to air flow path R1 through exposure hole 216 provided in air duct 20. Therefore, the air flowing along air flow path R1 cools control unit 80, and all of the air is discharged as working air. According to the above configuration, there is no need to provide a cooling air path for cooling control unit 80 separately from air flow path R1, which simplifies the structure of blower 10 and enables the blower to be made smaller.

[0074] In one or more embodiments, the air duct 20 and the motor housing 56 are made of resin. The entire controller casing 88 (for example, at least a portion of the casing) is made of metal.

[0075] To efficiently cool the control unit 80, it is desirable to use a material with excellent thermal conductivity for the portion of the controller casing 88 that houses the control board 82 and that is exposed to the airflow path R1. On the other hand, to reduce the overall mass of the blower 10, it is desirable to use a material with low mass for the airflow path 20 and the motor housing 56. According to the above configuration, the portion of the controller casing 88 that is exposed to the airflow path R1 is made of metal with excellent thermal conductivity. The airflow path 20 and the motor housing 56 are made of resin with low mass. This allows the control unit 80 to be efficiently cooled, and the weight of the blower 10 as a whole to be reduced.

[0076] In one or more embodiments, the portion of the controller casing 88 exposed to the air flow path R1 (an example of at least a portion of the casing) is positioned radially outward of an imaginary plane V extending along the inner surface of the air duct 20 at the portion where the exposure hole 216 is provided.

[0077] If the controller casing 88 is disposed radially inward of the air blower duct 20 relative to the imaginary plane V, the air blowing path R1 is narrowed in the portion where the controller casing 88 is disposed, which may increase pressure loss in the air blowing path R1. With the above configuration, the air blowing path R1 is not narrowed in the portion where the controller casing 88 is disposed. Therefore, it is possible to suppress an increase in pressure loss in the air blowing path R1.

[0078] In one or more embodiments, in the radial direction, the shortest distance d1 between the portion of the controller casing 88 exposed to the air flow path R1 and the imaginary surface V is 2 mm, and the longest distance d2 is 12 mm (an example of a distance between at least a portion of the casing and the imaginary surface being in the range of 2 mm-12 mm).

[0079] Generally, the smaller the distance between the controller casing 88 and the imaginary plane V, the more efficiently the control unit 80 can be cooled by the air flowing through the airflow path R1. According to the above configuration, the control unit 80 can be cooled efficiently.

[0080] In one or more embodiments, when viewing the exposure hole 216 from the radially outward direction, the electric motor 54 and the exposure hole 216 partially (for example, at least partially) overlap.

[0081] For example, if the electric motor 54 and the exposure hole 216 do not overlap when viewed from the radially outside, the air duct 20 may become excessively long. According to the above configuration, the electric motor 54 and the exposure hole 216 are arranged so as to at least partially overlap when viewed from the radially outside, and therefore the air duct 20 can be shortened.

[0082] In one or more embodiments, the fan 52 is an axial fan whose airflow direction coincides with the direction of the rotation axis of the fan 52. The fan 52 is disposed so that the direction of the rotation axis A1 is along the left-right direction (an example of the extension direction of the air duct). The control board 82 is configured to control the driving of the electric motor 54 so that the upstream side of the airflow direction of the fan 52 is the intake side and the downstream side of the airflow direction is the exhaust side. The exposure hole 216 is provided on the downstream side of the fan 52.

[0083] Typically, the flow velocity of air flowing through airflow path R1 is greater downstream of fan 52 than upstream of fan 52. With the above configuration, the controller casing 88 of control unit 80 is exposed to airflow path R1 downstream of fan 52. Therefore, air flows at a relatively high velocity in the portion of control unit 80 exposed to airflow path R1. With the above configuration, control unit 80 can be cooled efficiently.

[0084] In one or more embodiments, the electric motor 54 is a brushless motor. The control board 82 includes a plurality of switching elements 84 for switching the current supplied to the electric motor 54.

[0085] Generally, when electric motor 54 is a brushless motor, control board 82 is provided with a plurality of switching elements 84 for controlling the current supplied to the brushless motor. In this case, the amount of heat generated by control unit 80 is relatively large due to heat generated by the plurality of switching elements 84. With the above configuration, blower 10 equipped with a brushless motor can efficiently cool control unit 80 without reducing the volume of working air.

[0086] In one or more embodiments, when the exposure hole 216 is viewed from the radially outward direction, all of the switching elements 84 and the exposure hole 216 overlap (an example of the multiple switching elements and the exposure hole at least partially overlapping).

[0087] According to the above configuration, all of the multiple switching elements 84, which are parts of the control unit 80 that generate a relatively large amount of heat, overlap with the exposure holes 216 in the radial direction of the air duct 20. This makes it easier for the heat generated by the multiple switching elements 84 to be transferred to the parts of the controller casing 88 that are exposed to the air flow path R1. This makes it possible to efficiently suppress a rise in temperature of the control unit 80 as a whole. According to the above configuration, the control unit 80, which includes the multiple switching elements 84, can be efficiently cooled. [Explanation of symbols]

[0088] 10: Blower 12: Battery device 13: Blower body 14: Outer housing 16: Pair of shoulder straps 20: Air pipe 22: Operation grip 24: Charging connector 26: Discharge cable 28: Trigger 30: Air intake 32: Exhaust port 50: Blower unit 52: Fan 54: Electric motor 56: Motor housing 56a: 2nd outer surface 58: Diffuser cone 58a: Third outer surface 58b: First ventilation opening 60: Drive shaft 62: Hub 62a: 1st outer surface 62b: Second ventilation port 64: Blade 66: Cylindrical part 66a: Outer surface of cylindrical part 68: Bottom 68b: 1st communication hole 70: Lid 70a: outer surface of the lid 70b: 2nd communication hole 72: Support member 80: Control unit 82: Control board 84: Switching element 86: Heat dissipation material 88: Controller casing 90: Potting resin 92: Finn 100: Plate member 100a: outer surface of plate member 102: Exhaust port side end 158: Diffuser cone 210: 1st air pipe 212: Placement section 214: Cover member 216: Exposure hole 220, 320: 2nd air pipe 230: 3rd blow pipe 240: 4th blow pipe 560: Intake port end 620: Exhaust port end A1: Rotation axis R1: Air flow path R2: Circulation route V: Virtual plane

Claims

1. An intake port, An exhaust port, an air duct provided between the intake port and the exhaust port; a fan disposed inside the air duct; an electric motor disposed inside the air duct for driving the fan to rotate; a motor housing disposed inside the air duct and accommodating the electric motor; a control unit for controlling the electric motor, The control unit a control board for controlling the driving of the electric motor; a casing that houses the control board, The air duct is provided with an exposure hole that radially communicates the inside and outside of the air duct, the casing is attached to the air duct such that at least a portion of the casing entirely covers the exposure hole from the radially outer side, a blower, wherein the at least part of the casing is disposed radially outward of an imaginary plane extending along an inner surface of the air duct in a portion where the exposure hole is provided.

2. The air duct and the motor housing are made of resin, 2. The blower of claim 1, wherein said at least a portion of said casing is formed from metal.

3. 2. The blower of claim 1, wherein a distance between the at least part of the casing and the imaginary plane in the radial direction is within a range of 2 mm to 12 mm.

4. 2. The blower according to claim 1, wherein the electric motor and the exposure hole at least partially overlap when the exposure hole is viewed from the radially outer side.

5. the fan is an axial flow fan whose airflow direction coincides with the direction of the rotation axis of the fan, The fan is disposed so that the rotation axis direction is aligned with the extension direction of the air duct, the control board is configured to control the driving of the electric motor so that the upstream side of the air blowing direction of the fan is the air intake side and the downstream side of the air blowing direction is the air exhaust side, 2. The blower of claim 1, wherein the exposure hole is provided downstream of the fan.

6. the electric motor is a brushless motor, 2. The blower according to claim 1, wherein the control board includes a plurality of switching elements for switching the current supplied to the electric motor.

7. 7. The blower of claim 6, wherein the plurality of switching elements and the exposure holes at least partially overlap when the exposure holes are viewed from the radially outer side.

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