Patent ID: 12245553

Representative, non-limiting examples of the present disclosure will now be described in further detail with reference to the attached drawings. This detailed description is merely intended to teach a person of skill in the art further details for practicing aspects of the present teachings and is not intended to limit the scope of the present disclosure. Furthermore, each of the additional features and teachings disclosed below may be utilized separately or in conjunction with other features and teachings to provide improved blowers as well as methods for using and manufacturing the same.

Moreover, combinations of features and steps disclosed in the following detailed description may not be necessary to practice the present disclosure in the broadest sense, and are instead taught merely to particularly describe representative examples of the present disclosure. Furthermore, various features of the above-described and below-described representative examples, as well as the various independent and dependent claims, may be combined in ways that are not specifically and explicitly enumerated in order to provide additional useful embodiments of the present teachings.

All features disclosed in the description and/or the claims are intended to be disclosed separately and independently from each other for the purpose of original written disclosure, as well as for the purpose of restricting the claimed subject matter, independent of the compositions of the features in the embodiments and/or the claims. In addition, all value ranges or indications of groups of entities are intended to disclose every possible intermediate value or intermediate entity for the purpose of original written disclosure, as well as for the purpose of restricting the claimed subject matter.

In one or more embodiments, the airflow pipe and the motor housing may be constituted of resin. The at least part of the casing may be constituted of a metallic material.

In order to efficiently cool the control unit, it is desirable to use a material having high heat conductivity for a part of the casing housing the control board, the part being exposed to the airflow path. On the other hand, in order to reduce a mass of the blower as a whole, it is desirable to use a material having a small mass for the airflow pipe and the motor housing. According to the above configuration, the at least part of the casing exposed to the airflow path is constituted of a metallic material having high heat conductivity. The airflow pipe and the motor housing are constituted of resin having a small mass. Consequently, the control unit can efficiently be cooled and also reduction of a weight of the blower as a whole can be achieved.

In one or more embodiments, the at least part of the casing may be offset outwardly in the radial direction from a virtual surface, wherein the virtual surface extends along an inner surface of the airflow pipe at a part where the exposure hole is defined. Here, when the inner surface of the airflow pipe is a cylindrical surface, the “virtual surface” means a surface extending along the cylindrical surface.

When the casing is offset inwardly from the virtual surface in the radial direction of the airflow pipe, the airflow path is narrowed at the part where the casing is disposed, thus pressure loss may increase in the airflow path. According to the above configuration, the airflow path will not be narrowed at the part where the casing is disposed. Consequently, increase in pressure loss in the airflow path can be suppressed.

In one or more embodiments, in the radial direction, a distance between the at least part of the casing and the virtual surface may be within a range of 2 mm to 12 mm.

In general, when the distance between the casing and the virtual surface is smaller, the control unit can more efficiently be cooled by the air flowing in the airflow path. According to the above configuration, the control unit can efficiently be cooled.

In one or more embodiments, when the exposure hole is viewed from outside in the radial direction, the electric motor and the exposure hole may at least partially overlap.

For example, if the electric motor and the exposure hole do not overlap when the exposure hole is viewed from outside in the radial direction, the airflow pipe may become excessively long. According to the above configuration, the electric motor and the exposure hole at least partially overlap when the exposure hole is viewed from outside in the radial direction, thus the airflow pipe can be shortened.

In one or more embodiments, the fan may be an axial flow fan whose blowing direction is along a rotation axis of the fan. The rotation axis of the fan may be arranged along a direction in which the airflow pipe extends. The control board may be configured to control the electric motor so that an upstream side of the blowing direction is an inlet side and a downstream side of the blowing direction is an outlet side. The exposure hole may be disposed downstream from the fan.

In general, a flow rate of air flowing in the airflow path is larger at a position downstream from the axial flow fan than a position upstream therefrom. According to the above configuration, the casing of the control unit is exposed to the airflow path at a position downstream from the axial flow fan. Thus, air having a relatively large flow rate flows at the part where the control unit is exposed to the airflow path. According to the above configuration, the control unit can efficiently be cooled.

In one or more embodiments, the electric motor may be a brushless motor. The control board may comprise a plurality of switching elements configured to control current supplied to the electric motor.

In general, when the electric motor is a brushless motor, a plurality of switching elements configured to control current supplied to the brushless motor is disposed on the control board. In this case, due to heat generation by the plurality of switching elements, an amount of heat generated by the control unit relatively increases. According to the above configuration, in the blower including the brushless motor, the control unit can efficiently be cooled without reducing a flow rate of blowing air.

In one or more embodiments, when the exposure hole is viewed from outside in the radial direction, the plurality of switching elements and the exposure hole may at least partially overlap.

According to the above configuration, the plurality of switching elements, which is the parts whose heat generation amount is relatively large within the control unit, and the exposure hole at least partially overlap in the radial direction of the airflow pipe. Thus, the heat generated by the plurality of switching elements tends to be dissipated to the part of the casing exposed to the airflow path. Consequently, temperature increase in the control unit as a whole can efficiently be suppressed. According to the above configuration, the control unit including the plurality of switching elements can efficiently be cooled.

EMBODIMENT

As illustrated inFIG.1, a blower10includes a battery device12, a blower body13, and a pair of shoulder belts16. A user wears the pair of shoulder belts16on his/her shoulder, by which the user can hold the blower10on his/her back. In other words, the blower10of the present embodiment is a backpack blower. In the explanation below, when the user wears the blower10on his/her back, an up-down direction, a left-right direction and a front-rear direction viewed from the user will be referred to as an up-down direction, a left-right direction and a front-rear direction of the blower10.

Configuration of Battery Device12

The battery device12houses a plurality of battery cells (not illustrated). The battery device12includes a charging connector24and a discharging cable26. The discharging cable26is connected to the blower body13. The plurality of battery cells can be charged from an external power source (not illustrated) by connecting a charging cable (not illustrated) extending from the external power source to the charging connector24. The plurality of battery cells can discharge to the blower body13via the discharging cable26.

Configuration of Blower Body13

The blower body13includes an outer housing14, an airflow pipe20and an operation grip22. As illustrated inFIG.2, the outer housing14includes an inlet30on its left side. The inlet30connects between the inside and outside of the outer housing14such that the inside and the outside are in communication. The outer housing14houses a part of the airflow pipe20. The outer housing14holds the airflow pipe20such that a direction along which a first airflow pipe210to be described later extends is defined along the left-right direction.

Configuration of Airflow Pipe20

The airflow pipe20includes a first airflow pipe210which is substantially cylindrical and extends in the left-right direction, a second airflow pipe220which is substantially cylindrical and bent toward the front as it extends rightward, a third airflow pipe230which has an accordion structure and extends in the front-rear direction, and a fourth airflow pipe240which is substantially cylindrical and extends in the front-rear direction. The third airflow pipe230is configured to extend and contract. The first airflow pipe210, the second airflow pipe220, the third airflow pipe230and the fourth airflow pipe240are connected in series. The left end of the first airflow pipe210is directed to the inlet30and communicates with the inlet30. The front end of the fourth airflow pipe240includes an outlet32. As described above, the airflow pipe20is configured such that its one end communicates with the inlet30and the other end functions as the outlet32. In the present disclosure, with respect to the direction in which the airflow pipe20extends, a side toward the inlet30may be referred to an inlet side and a side toward the outlet32may be referred to as an outlet side. For example, the left side of the first airflow pipe210may be referred to as the inlet side and the right side of the first airflow pipe210may be referred to as the outlet side.

Configuration of Operation Grip22

As illustrated inFIG.1, an operation grip22is disposed on the fourth airflow pipe240at a position which allows the user to operate the operation grip22by gripping it. The user adjusts a posture of the fourth airflow pipe240while gripping the operation grip22, by which the user can adjust a direction in which the outlet32is oriented. A plurality of switches, such as a trigger28, to be operated by the user is disposed on the operation grip22.

Configuration of Airflow Unit50

As illustrated inFIG.3, the blower body13further includes an airflow unit50disposed in the airflow pipe20and configured to supply air from the inlet30toward the outlet32through the airflow pipe20. The airflow unit50includes a fan52, an electric motor54configured to drive the fan52, a motor housing56that houses the electric motor54, and a diffuser cone58connected to the right end of the motor housing56.

Configuration of Electric Motor54

The electric motor54includes a drive shaft60configured to rotate about a rotation axis A1which is along the left-right direction. The electric motor54of the present embodiment is a brushless motor and includes a stator and a rotor (not illustrated). The drive shaft60is fixed to the rotor, and the drive shaft60rotates about the rotation axis A1when electric power is supplied to the electric motor54.

Configuration of Fan52

As illustrated inFIG.4, the fan52includes a hub62fixed to the drive shaft60from the inlet side and a plurality of blades64disposed at a first outer surface62aof the hub62. The hub62is configured to rotate about the rotation axis A1. The first outer surface62ahas an axisymmetric shape about the rotation axis A1of the drive shaft60. An outlet-side end620, which is the end of the first outer surface62aon the outlet side, has a first outer diameter φ1(seeFIG.10). In the present embodiment, the fan52is an axial flow fan. For example, when the fan52rotates counterclockwise as the airflow unit50is viewed from the inlet side, the fan52generates airflow from the inlet side toward the outlet side along the rotation axis A1(e.g., rightward inFIG.4).

Configuration of Motor Housing56

As illustrated inFIG.3, the motor housing56includes a cylindrical portion66extending along the rotation axis A1, a bottom portion68disposed on the outlet side of the electric motor54, and a lid portion70disposed on the inlet side of the electric motor54. The motor housing56is supported within the first airflow pipe210by a plurality of support members72formed at the cylindrical portion66. The cylindrical portion66, the bottom portion68, the plurality of support members72and the first airflow pipe210are seamlessly and integrally formed. The lid portion70is fixed to the cylindrical portion66by screws (not illustrated). Thus, the electric motor54is housed in the motor housing56by inserting the electric motor54into the cylindrical portion66and then fixing the lid portion70to the cylindrical portion66. In the present embodiment, resin such as nylon is used for the cylindrical portion66, the bottom portion68, the lid portion70, the plurality of support members72, and the first airflow pipe210.

As illustrated inFIG.4, the cylindrical portion66includes an outer surface66ahaving a substantially cylindrical shape about the rotation axis A1of the drive shaft60. The lid portion70includes an outer surface70ahaving an axisymmetric shape about the rotation axis A1. With the lid portion70fixed to the cylindrical portion66, the outer surface66aand the outer surface70aare substantially smoothly connected to each other along the rotation axis A1. Thus, in the present disclosure, the outer surface66aand the outer surface70amay collectively be referred to as “second outer surface56a”. An inlet-side end560, which is the end of the second outer surface56aon the inlet side, has a second outer diameter φ2(seeFIG.10). Here, a second vent62bis defined between the outlet-side end620of the hub62and the inlet-side end560of the motor housing56. The second vent62bis defined along a circumferential direction of the rotation axis A1between the outlet-side end620and the inlet-side end560. The second vent62bhas a width in the axial direction of the rotation axis A1. In view of the above, the second vent62bis defined such that its circumferential end is constituted of the outlet-side end620and the inlet-side end560. The second vent62bconnects between the inside of the hub62and an airflow path R1(seeFIG.8, to be described later) such that they are in communication.

The bottom portion68includes first communication holes68bdefined between the electric motor54and the diffuser cone58in the direction along which the rotation axis A1extends. The first communication holes68bconnect between the inside of the motor housing56and the inside of the diffuser cone58such that they are in communication. In the present embodiment, the first communication holes68bare defined with a predetermined angular interval (e.g., interval of 60 degrees) from one another in the circumferential direction. The lid portion70includes second communication holes70bdefined between the hub62and the electric motor54in the direction in which the rotation axis A1extends. The second communication holes70bconnect between the inside of the hub62and the inside of the motor housing56such that they are in communication. In the present embodiment, the second communication holes70bare defined with a predetermined angular interval (e.g., interval of 40 degrees) from one another in the circumferential direction.

Configuration of Diffuser Cone58

The diffuser cone58is connected to the outlet-side end of the cylindrical portion66of the motor housing56and extends along the rotation axis A1. A part of the diffuser cone58extends toward the outlet side beyond the right end of the first airflow pipe210. In other words, the diffuser cone58extends in both the first airflow pipe210and the second airflow pipe220. The diffuser cone58includes a third outer surface58ahaving an axisymmetric shape about the rotation axis A1. The third outer surface58ais smoothly connected to the second outer surface56aalong the direction in which the rotation axis A1extends. A diameter of the third outer surface58ais reduced from the inlet side toward the outlet side along the rotation axis A1. The diffuser cone58includes a first vent58bwhich has a substantially circular shape and whose circumferential end is the outlet-side end of the third outer surface58a. The first vent58bis open along the direction in which the rotation axis A1extends. The first vent58bhas a second inner diameter φ4(seeFIG.12). The first vent58bconnects between the airflow path R1(seeFIG.8) to be described and the inside of the diffuser cone58such that they are in communication.

Configuration of Control Unit80

As illustrated inFIG.3, the blower body13further includes a control unit80configured to control the electric motor54of the airflow unit50. The control unit80is disposed at a mounting part212disposed at a top portion of the first airflow pipe210. The control unit80is fixed to the first airflow pipe210by the mounting part212and the cover member214to be screwed to the mounting part212. The control unit80is electrically connected to each of the battery device12(seeFIG.1), the trigger28(seeFIG.1) and the electric motor54. When the trigger28is operated by the user, the control unit80adjusts electric power supplied from the battery device12and supplies the same to the electric motor54to drive the electric motor54. In the present embodiment, the control unit80is configured to control the electric motor54so that the fan52generates airflow from the inlet side toward the outlet side along the rotation axis A1.

As illustrated inFIG.5, the control unit80includes a control board82, a plurality of switching elements84disposed on the upper surface of the control board82, heat dissipation members86disposed in tight contact with the lower surface of the control board82, a controller casing88that houses the control board82, the plurality of switching elements84and the heat dissipation members86, and potting resin90that seals the control board82, the plurality of switching elements84and the heat dissipation members86. The heat dissipation members86are also in tight contact with the upper surface of the controller casing88. The controller casing88includes a plurality of fins92at a part of its lower surface. The plurality of switching elements84is disposed above a portion of the controller casing88where the plurality of fins92is disposed. In the present embodiment, a sheet-shaped aluminum alloy is used for the heat dissipation members86. In the present embodiment, a metallic material such as aluminum is used for the controller casing88. In the present embodiment, the plurality of switching elements84is FETs (field effect transistors) and constitutes an inverter circuit. Thus, the control unit80is configured to convert direct power supplied from the battery device12(seeFIG.1) to three-phase alternating power and supply the same to the electric motor54.

As illustrated inFIG.4, an upper portion of the first airflow pipe210comprises an exposure hole216connecting the inside and the outside of the first airflow pipe210such that they are in communication in the radial direction of the first airflow pipe210. The exposure hole216is offset from the fan52toward the outlet side. The control unit80is attached to the first airflow pipe210such that a part of the controller casing88covers the entirety of the exposure hole216from outside in the radial direction of the first airflow pipe210. With the control unit80attached to the first airflow pipe210, a part of the lower surface of the controller casing88where the plurality of fins92is disposed (seeFIG.5) is exposed to the airflow path R1(seeFIG.8) to be described later.

As illustrated inFIG.6, in the present embodiment, a part of the electric motor54, the plurality of switching elements84and the heat dissipation members86are disposed such that these members and the exposure hole216overlap when the exposure hole216is viewed along the up-down direction from the outside of the first airflow pipe210in the radial direction. It should be noted that, inFIG.6, components except the electric motor54, the plurality of switching elements84, the heat dissipation members86, the mounting part212(the first airflow pipe210) and the exposure hole216are omitted for clearer explanation.

As illustrated inFIG.7, the lower surface of the controller casing88has a substantially planar shape extending along the front-rear and left-right directions. The lower surface of the controller casing88is offset outwardly in the radial direction of the first airflow pipe210from a virtual surface V. The virtual surface V extends along the inner surface of the first airflow pipe210at a part where the exposure hole216is defined. In the radial direction of the first airflow pipe210, a minimum distance d1between the lower surface of the controller casing88and the virtual surface V is 2 mm. In the radial direction of the first airflow pipe210, a maximum distance d2between the lower surface of the controller casing88and the virtual surface V is 12 mm.

Airflow Path R1

As illustrated inFIG.8, the airflow path R1which extends from the left end of the first airflow pipe210to the second airflow pipe220passing through the outside of the hub62, the outside of the motor housing56and the outside of the diffuser cone58in this order is defined in the airflow pipe20. Although not illustrated, after reaching the second airflow pipe220, the airflow path R1further passes through the third airflow pipe230(seeFIG.2) and the fourth airflow pipe240(seeFIG.2) and then reaches the outlet32(seeFIG.2). In the blower10of the present embodiment, when the fan52generates airflow from the inlet side toward the outlet side, air from the inlet30flows to the outlet32through the outside of the hub62, the outside of the motor housing56and the outside of the diffuser cone58in the airflow path R1.

As described above, the plurality of fins92(seeFIG.5) of the controller casing88which covers the exposure hole216is exposed to the airflow path R1. Thus, the air flowing along the airflow path R1guides the heat dissipated from the plurality of fins92exposed to the airflow path R1to the outlet32. In other words, the air flowing along the airflow path R1is used as cooling air which suppresses temperature rise in the control unit80. In the blower10of the present embodiment, all the air used as the cooling air is exhausted from the outlet32. Thus, in the blower10of the present embodiment, the control unit80can be cooled without reducing the flow rate of blowing air.

Circulation Path R2

A circulation path R2which extends from the airflow path R1and goes back to the airflow path R1through the first vent58b, the inside of the diffuser cone58, the first communication holes68b, the inside of the motor housing56, the second communication holes70b, the inside of the hub62and the second vent62bin this order is defined in the airflow unit50. In the circulation path R2, the air flowing in the airflow path R1flows into the diffuser cone58through the first vent58b, flows through the inside of the motor housing56, and flows toward the airflow path R1through the second vent62b.

As illustrated inFIG.9, when the air flows along the airflow path R1, the air flowing along the first outer surface62aseparates from the first outer surface62aat the outlet-side end620, by which negative pressure which takes the air out of the circulation path R2toward the airflow path R1is generated at the second vent62b. On this occasion, as illustrated inFIG.8, negative pressure which takes the air into the circulation path R2from the airflow path R1is generated at the first vent58b. As described above, when the air flows along the airflow path R1, a part of the air flowing along the airflow path R1flows along the circulation path R2. The air flowing along the circulation path R2guides the heat generated in the electric motor54housed in the motor housing56toward the airflow path R1. In other words, the air flowing along the circulation path R2is used as cooling air which suppresses temperature rise in the electric motor54.

Negative Pressure Increasing Mechanism in Vicinity of Second Vent62b

As illustrated inFIG.10, in the present embodiment, the first outer diameter φ1of the outlet-side end620of the hub62is larger than the second outer diameter φ2of the inlet-side end560of the motor housing56. As described above, each of the hub62and the motor housing56has an axisymmetric shape about the rotation axis A1of the drive shaft60, thus the inlet-side end560is offset inward in the radial direction of the rotation axis A1from the outlet-side end620. Consequently, a distance from a point at which the air flowing along the first outer surface62aseparates from the first outer surface62a(i.e., separation point) to a point at which the separated air attaches again to the second outer surface56a(i.e., re-attachment point) increases. As a result, negative pressure which generates airflow in the circulation path R2increases. Thus, in the blower10of the present embodiment, the flow rate of the cooling air for cooling the electric motor54can be increased.

Ratio φ1/φ2of First Outer Diameter φ1to Second Outer Diameter φ2

As illustrated inFIG.11, the flow rate of the cooling air for cooling the electric motor54(flow rate of the cooling air) and the flow rate of the blowing air change depending on a ratio φ1/φ2of the first outer diameter φ1to the second outer diameter φ2. The flow rate of the cooling air monotonically increases when the ratio φ1/φ2of the first outer diameter φ1to the second outer diameter φ2increases from 100% to 115%, while the flow rate of the cooling air monotonically decreases when the ratio φ1/φ2of the first outer diameter φ1to the second outer diameter φ2increases beyond 116%. The flow rate of the blowing air monotonically decreases as the ratio φ1/φ2of the first outer diameter φ1to the second outer diameter φ2increases. Thus, when the ratio φ1/φ2of the first outer diameter φ1to the second outer diameter φ2is within a range of 101% to 116%, decrease in the flow rate of the blowing air can be suppressed while the flow rate of the cooling air is efficiently increased. InFIG.11, with respect to the rate of change of each of the flow rate of the cooling air and the flow rate of the blowing air when the ratio φ1/φ2is changed, the rate of change in the case of φ1/φ2being 100% is indicated as 100%.

In particular, when the ratio φ1/φ2of the first outer diameter φ1to the second outer diameter φ2increases from 100% to 103%, a gradient of the rate of change of the flow rate of cooling air (rate of increase) is relatively large. A gradient of the rate of change of the flow rate of the blowing air (rate of decrease) is substantially constant regardless of the ratio φ1/φ2of the first outer diameter φ1to the second outer diameter φ2. Accordingly, when the ratio φ1/φ2of the first outer diameter φ1to the second outer diameter φ2is 103%, it is possible to further increase the flow rate of the cooling air efficiently while further suppressing decrease in the flow rate of the blowing air. For the above reason, in the blower10of the present embodiment, the ratio φ1/φ2of the first outer diameter φ1to the second outer diameter φ2is 103%.

Ratio φ3/φ2of First Inner Diameter φ3to Second Outer Diameter φ2

As illustrated inFIG.10, the first airflow pipe210has a first inner diameter φ3radially outside the outlet-side end620. When the ratio φ3/φ2of the first inner diameter φ3to the second outer diameter φ2is too small, increasing the first outer diameter φ1narrows the airflow path R1, by which pressure loss may be increased to a great extent in the airflow path R1. On the other hand, when the ratio φ3/φ2of the first inner diameter φ3to the second outer diameter φ2is too large, the airflow generated in the airflow path R1by driving the fan52may be disturbed. In the present embodiment, the ratio φ3/φ2of the first inner diameter φ3to the second outer diameter φ2is 187%. Consequently, increase in pressure loss in the airflow path R1can be suppressed and also disturbance of the airflow in the airflow path R1can be suppressed.

Ratio φ4/φ2of Second Inner Diameter φ4to Second Outer Diameter φ2

Further, when the ratio φ4/φ2of the second inner diameter φ4of the first vent58b(seeFIG.12) to the second outer diameter φ2is too small, an amount of air taken into the circulation path R2at the first vent58bmay be excessively small. On the other hand, when the ratio φ4/φ2of the second inner diameter φ4to the second outer diameter φ2is too large, the amount of air taken into the circulation path R2at the first vent58bmay be excessively large. In the present embodiment, the ratio φ4/φ2of the second inner diameter φ4to the second outer diameter φ2is 33%. Consequently, the amount of air taken into the circulation path R2at the first vent58bcan be a suitable amount.

Variants

In the above embodiments, the configuration in which the blower10is a backpack blower was described. In another embodiment, the blower10may be a blower other than a backpack blower. For example, the blower10may be a handheld blower or the like.

In the above embodiment, the configuration in which the blower10includes the battery device12connected to the blower body13via the discharging cable26and electric power is supplied from the battery device12to the electric motor54was described. In another embodiment, instead of the battery device12, the blower10may include at least one battery pack (another example of a battery device) which is disposed at the blower body13and detachably attached to a battery attachment portion (not illustrated) including connection terminal(s). When the at least one battery pack is attached to the battery attachment portion, electric power may be supplied from the at least one battery pack to the electric motor54. In yet another embodiment, instead of the battery device12, the blower10may include a power supply cord for connecting the blower body13to an external power source, and the blower10may be configured such that electric power is supplied from the external power source to the electric motor54via the power supply cord.

In the above embodiment, the configuration in which the airflow pipe20includes the first airflow pipe210, the second airflow pipe220, the third airflow pipe230and the fourth airflow pipe240was described. In another embodiment, the airflow pipe20may not include at least one of the second airflow pipe220, the third airflow pipe230and the fourth airflow pipe240.

In the above embodiment, the configuration in which the electric motor54is a brushless motor was described. In another embodiment, the electric motor54may be a motor other than a brushless motor. For example, the electric motor54may be a brushed motor.

In the above embodiment, the configuration in which the fan52is an axial flow fan was described. In another embodiment, the fan52may be a fan other than an axial flow fan. For example, the fan52may be a centrifugal fan such as a sirocco fan.

In the above embodiment, the configuration in which the hub62is fixed to the drive shaft60was described. In another embodiment, a speed reducer (not illustrated) may be disposed between the hub62and the drive shaft60. In this case, the hub62may be fixed to an output shaft different from the drive shaft60and the output saft may be coupled to the drive shaft60via the speed reducer. In other words, the hub62may be rotatably disposed about a rotation axis different from the rotation axis A1of the drive shaft60.

In the above embodiment, the configuration in which the cylindrical portion66, the bottom portion68, the plurality of support members72and the first airflow pipe210are seamlessly and integrally formed was described. In another embodiment, at least one of the cylindrical portion66, the bottom portion68, the plurality of support members72and the first airflow pipe210may be formed as separate member(s).

In the above embodiment, the configuration in which resin such as nylon is used for the cylindrical portion66, the bottom portion68, the lid portion70, the plurality of support members72and the first airflow pipe210was described. In another embodiment, a material other than resin may be used for at least one of the cylindrical portion66, the bottom portion68, the lid portion70, the plurality of support members72and the first airflow pipe210. For example, aluminum or the like may be used for at least one of the cylindrical portion66, the bottom portion68, the lid portion70, the plurality of support members72and the first airflow pipe210.

In the above embodiment, the configuration in which an aluminum alloy is used for the heat dissipation members86was described. In another embodiment, a material other than the aluminum alloy may be used for the heat dissipation members86. For example, silicon rubber or the like may be used for the heat dissipation members86.

In the above embodiment, the configuration in which a metallic material such as aluminum is used for the controller casing88was described. In another embodiment, a material other than a metallic material may be used for the controller casing88. For example, nylon or the like may be used for the controller casing88.

In the above embodiment, the configuration in which the exposure hole216is defined downstream from (on the outlet side of) the fan52and the controller casing88is exposed to the airflow path R1at a position downstream from the fan52was described. In another embodiment, the exposure hole216may be defined upstream from (on the inlet side of) the fan52and the controller casing88may be exposed to the airflow path R1at a position upstream from the fan52.

In the above embodiment, the configuration in which, when the exposure hole216is viewed from the outside of the first airflow pipe210in the radial direction, the electric motor54and the exposure hole216partially overlap was described. In another embodiment, when the exposure hole216is viewed from the outside of the first airflow pipe210in the radial direction, the electric motor54and the exposure hole216may not overlap. In this case, the exposure hole216may be offset toward the outlet from the electric motor54or may be offset toward the inlet from the electric motor54.

In the above embodiment, the configuration in which the lower surface of the controller casing88has a substantially planar shape was described. In another embodiment, the lower surface of the controller casing88may not have a substantially planar shape. For example, the lower surface of the controller casing88may have a shape along the virtual surface V.

In the above embodiment, the configuration in which the lower surface of the controller casing88is offset outwardly in the radial direction of the first airflow pipe210from the virtual surface V which extends along the inner surface of the first airflow pipe210at a part where the exposure hole216is defined was described. In another embodiment, the lower surface of the controller casing88may not be offset outwardly in the radial direction of the first airflow pipe210from the virtual surface V which extends along the inner surface of the first airflow pipe210at a part where the exposure hole216is defined. For example, the lower surface of the controller casing88may be offset inwardly in the radial direction of the first airflow pipe210from the virtual surface V which extends along the inner surface of the first airflow pipe210at a part where the exposure hole216is defined.

In the above embodiment, the configuration in which the mounting part212and the exposure hole216are disposed at an upper portion of the first airflow pipe210and the control unit80is attached to the upper portion of the first airflow pipe210was described. In another embodiment, the mounting part212and the exposure hole216may be disposed at a position other than the upper portion of the first airflow pipe210and the control unit80may be attached to a portion other than the upper portion of the first airflow pipe210. For example, the mounting part212and the exposure hole216may be disposed at, for example, a lower portion of the first airflow pipe210, and the control unit80may be attached to, for example, the lower portion of the first airflow pipe210.

In the above embodiment, the configuration in which the plurality of switching elements84is FETs was described. In another embodiment, the plurality of switching elements84may be switching elements other than FETs. For example, the plurality of switching elements84may be IGBTs (insulated-gate bipolar transistors) or the like.

In the above embodiment, the configuration in which the ratio φ1/φ2of the first outer diameter φ1to the second outer diameter φ2is 103% was described. In another embodiment, the ratio φ1/φ2of the first outer diameter φ1to the second outer diameter φ2may be suitably changed within a range from 101% to 116%.

In the above embodiment, the configuration in which the ratio φ3/φ2the first inner diameter φ3to the second outer diameter φ2is 187% was described. In another embodiment, the ratio φ3/φ2of the first inner diameter φ3to the second outer diameter φ2may be suitably changed within a range from 175% to 195%.

In the above embodiment, the configuration in which the ratio φ4/φ2of the second inner diameter φ4to the second outer diameter φ2is 33% was described. In another embodiment, the ratio φ4/φ2of the second inner diameter φ4to the second outer diameter φ2may be suitably changed within a range from 15% to 50%.

As illustrated inFIG.13, in another embodiment, the blower10may include a second airflow pipe320instead of the second airflow pipe220, and may include a diffuser cone158instead of the diffuser cone58. The second airflow pipe320has a shape which curves downward as it extends rightward. The diffuser cone158has a shape which curves downward as it extends rightward along the curve shape of the second airflow pipe320. In this case, the first vent58bopens along the direction in which the second airflow pipe320extends.

As illustrated inFIG.14, in another embodiment, a plate member100having a circular plate shape may be disposed between the hub62and the motor housing56. The plate member100may include an outer surface100ahaving an axisymmetric shape about the rotation axis A1. The plate member100may be fixed to the drive shaft60(seeFIG.4) independently from the hub62. The second vent62bmay not be defined such that its circumferential end is constituted of the outlet-side end620of the hub62and the inlet-side end560of the motor housing56. Instead, the second vent62bmay be defined such that its circumferential end is constituted of the inlet-side end560and an outlet-side end102which is the end of the outer surface100aof the plate member100on the outlet side. Although not illustrated, the outer diameter of the outlet-side end102may be larger than the second outer diameter φ2of the inlet-side end560. In this configuration, the first outer diameter φ1of the outlet-side end620may be equal to or greater than the second outer diameter φ2of the inlet-side end560. In this case, the plate member100increases negative pressure which generates airflow in the circulation path R2. In other words, the plate member100increases the flow rate of the cooling air for cooling the electric motor54.

Corresponding Relationships

As described above, in one or more embodiments, the blower10comprises the inlet30, the outlet32, the airflow pipe20(specifically, the first airflow pipe210) disposed between the inlet30and the outlet32, the fan52disposed in the airflow pipe20, the electric motor54disposed in the airflow pipe20and configured to drive the fan52, the motor housing56that is disposed in the airflow pipe20and houses the electric motor54, and the control unit80configured to control the electric motor54. The control unit80comprises the control board82configured to control the electric motor54and the controller casing88(an example of a casing) that houses the control board82. The airflow pipe20comprises the exposure hole216connecting the inside of the airflow pipe20to the outside of the airflow pipe20such that the inside and the outside are in communication in the radial direction. The controller casing88is attached to the airflow pipe20such that a part of the controller casing88(an example of at least part of the casing) covers an entirety of the exposure hole216from outside in the radial direction.

According to the above configuration, the controller casing88is attached to the airflow pipe20such that it covers the entirety of the exposure hole216. At this time, a part of the controller casing88is exposed to the airflow path R1through the exposure hole216defined in the airflow pipe20. Thus, the air flowing along the airflow path R1cools the control unit80, and all the air used for the cooling is exhausted as the blowing air. According to the above configuration, it is not necessary to provide a cooling air path for cooling the control unit80separately from the airflow path R1, and thus a structure of the blower10can be simplified and the blower10can be downsized.

In one or more embodiments, the airflow pipe20and the motor housing56are constituted of resin. An entirety of the controller casing88(an example of at least part of the casing) is constituted of a metallic material.

In order to efficiently cool the control unit80, it is desirable to use a material having high heat conductivity for a portion of the controller casing88housing the control board82, the portion being exposed to the airflow path R1. On the other hand, in order to reduce a mass of the blower10as a whole, it is desirable to use a material having a small mass for the airflow pipe20and the motor housing56. According to the above configuration, the at least part of the controller casing88exposed to the airflow path R1is constituted of a metallic material having high heat conductivity. The airflow pipe20and the motor housing56are constituted of resin having a small mass. Consequently, the control unit80can efficiently be cooled and also reduction of a weight of the blower10as a whole can be achieved.

In one or more embodiments, the portion of the controller casing88exposed to the airflow path R1(an example of at least part of the casing) is offset outwardly in the radial direction from the virtual surface V, in which the virtual surface V extends along the inner surface of the airflow pipe20at the part where the exposure hole216is defined.

When the controller casing88is offset inwardly from the virtual surface V in the radial direction of the airflow pipe20, the airflow path R1is narrowed at the part where the controller casing88is disposed, thus there is a risk that pressure loss increases in the airflow path R1. According to the above configuration, the airflow path R1will not be narrowed at the part where the controller casing88is disposed. Consequently, increase in pressure loss in the airflow path R1can be suppressed.

In one or more embodiments, in the radial direction, the minimum distance d1between the part of the controller casing88exposed to the airflow path R1and the virtual surface V is 2 mm and the maximum distance d2therebetween is 12 mm (an example of a distance between the at least part of the casing and the virtual surface being within a range of 2 mm to 12 mm).

In general, when the distance between the controller casing88and the virtual surface V is smaller, the control unit80can more efficiently be cooled by the air flowing in the airflow path R1. According to the above configuration, the control unit80can efficiently be cooled.

In one or more embodiments, when the exposure hole216is viewed from outside in the radial direction, the electric motor54and the exposure hole216partially (an example of at least partially) overlap.

For example, if the electric motor54and the exposure hole216do not overlap when the exposure hole216is viewed from outside in the radial direction, the airflow pipe20may become excessively long. According to the above configuration, the electric motor54and the exposure hole216are arranged such that they at least partially overlap when the exposure hole216is viewed from outside in the radial direction, thus the airflow pipe20can be shortened.

In one or more embodiments, the fan52is an axial flow fan whose blowing direction is along the rotation axis of the fan52. The rotation axis A1of the fan52is arranged along the left-right direction (an example of a direction in which the airflow pipe extends). The control board82is configured to control the electric motor54so that the upstream side of the blowing direction of the fan52is the inlet side and the downstream side of the blowing direction of the fan52is the outlet side. The exposure hole216is disposed downstream from the fan52.

In general, the flow rate of air flowing in the airflow path R1is greater on the downstream side than on the upstream side from the fan52. According to the above configuration, the controller casing88of the control unit80is exposed to the airflow path R1at a position downstream from the fan52. Thus, air having a relatively large flow rate flows at the part where the control unit80is exposed to the airflow path R1. According to the above configuration, the control unit80can efficiently be cooled.

In one or more embodiments, the electric motor54is a brushless motor. The control board82comprises the plurality of switching elements84configured to control current supplied to the electric motor54.

In general, when the electric motor54is a brushless motor, the plurality of switching elements84configured to control current supplied to the brushless motor is disposed on the control board82. In this case, due to heat generation by the plurality of switching elements84, an amount of heat generated by the control unit80relatively increases. According to the above configuration, in the blower10including a brushless motor, the control unit80can efficiently be cooled without reducing the flow rate of the blowing air.

In one or more embodiments, when the exposure hole216is viewed from outside in the radial direction, all of the plurality of switching elements84and the exposure hole216overlap (an example of a plurality of switching elements and the exposure hole at least partially overlapping).

According to the above configuration, all the plurality of switching elements84, which is the parts whose heat generation amount is relatively large within the control unit80, and the exposure hole216overlap in the radial direction of the airflow pipe20. Thus, the heat generated by the plurality of switching elements84tends to be dissipated to the part of the controller casing88exposed to the airflow path R1. Consequently, temperature increase in the control unit80as a whole can efficiently be suppressed. According to the above configuration, the control unit80including the plurality of switching elements84can efficiently be cooled.