Blower apparatus and vacuum cleaner

A blower apparatus includes a motor portion having a central axis extending in a vertical direction; an impeller arranged above the motor portion, joined to a rotating portion of the motor portion, and arranged to rotate to send a gas from above radially outward; an impeller cover portion including an inner surface arranged to cover an outer circumference of the impeller and an upper side of an outer edge portion of the impeller, and further including an air inlet defined in a center thereof; a body cover portion joined to the impeller cover portion, arranged to cover an outer circumference of the motor portion, and arranged to define a tubular space between the body cover portion and a housing tubular portion defining an outer surface of the motor portion and extending in the vertical direction to assume a tubular shape; and a plurality of guide vanes arranged in a circumferential direction in the tubular space, and each of which is arranged to extend in a radial direction between an inner surface of the body cover portion and the housing tubular portion. Each of the guide vanes includes a guide vane upper portion arranged on an upper side, and a guide vane lower portion arranged on a lower side of the guide vane upper portion. The guide vane upper portion is inclined to a greater degree with respect to an axial direction than the guide vane lower portion. A lower end of the guide vane is arranged forward of an upper end of the guide vane with respect to a rotation direction of the impeller. The lower end of at least one of the guide vanes is arranged above a lower end of the housing tubular portion.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an electric blower apparatus and a vacuum cleaner. The blower apparatus is installed in, for example, a vacuum cleaner.

2. Description of the Related Art

Blower apparatuses installed in vacuum cleaners are required to have a high static pressure. Such blower apparatuses are disclosed in, for example, JP-A 2010-281232 and JP-A 2011-80427. In each of these blower apparatuses, plate-shaped air guides are provided to guide a flow of air downward from a lateral side of an impeller. The air is sucked in through a center of the impeller, and is sent radially outward from the impeller. The air is then guided to a space radially outside of a motor arranged below through the air guides.

Each of the plate-shaped air guides, which are arranged to downwardly guide air sent radially outward from the impeller, includes a curved portion which is inclined to guide the flow of air, but when the impeller rotates at a high speed, a separation of the air may occur at a surface of any air guide to cause noise. A reduction in noise is particularly important when the blower apparatus is used in a consumer product, such as, for example, a vacuum cleaner.

The present invention has been conceived to reduce noise of a blower apparatus while maintaining a high static pressure of the blower apparatus.

SUMMARY OF THE INVENTION

A blower apparatus according to a preferred embodiment of the present invention includes a motor portion having a central axis extending in a vertical direction; an impeller arranged above the motor portion, joined to a rotating portion of the motor portion, and arranged to rotate to send a gas from above radially outward; an impeller cover portion including an inner surface arranged to cover an outer circumference of the impeller and an upper side of an outer edge portion of the impeller, and further including an air inlet defined in a center thereof; a body cover portion joined to the impeller cover portion, arranged to cover an outer circumference of the motor portion, and arranged to define a tubular space between the body cover portion and a housing tubular portion defining an outer surface of the motor portion and extending in the vertical direction to assume a tubular shape; and a plurality of guide vanes arranged in a circumferential direction in the tubular space, and each of which is arranged to extend in a radial direction between an inner surface of the body cover portion and the housing tubular portion. Each of the guide vanes includes a guide vane upper portion arranged on an upper side, and a guide vane lower portion arranged on a lower side of the guide vane upper portion. The guide vane upper portion is inclined to a greater degree with respect to an axial direction than the guide vane lower portion. A lower end of the guide vane is arranged forward of an upper end of the guide vane with respect to a rotation direction of the impeller. The lower end of at least one of the guide vanes is arranged above a lower end of the housing tubular portion.

A blower apparatus according to another preferred embodiment of the present invention includes a motor portion having a central axis extending in a vertical direction; an impeller arranged above the motor portion, joined to a rotating portion of the motor portion, and arranged to rotate to send a gas from above radially outward; an impeller cover portion including an inner surface arranged to cover an outer circumference of the impeller and an upper side of an outer edge portion of the impeller, and further including an air inlet defined in a center thereof; a body cover portion joined to the impeller cover portion, arranged to cover an outer circumference of the motor portion, and arranged to define a tubular space between the body cover portion and a housing tubular portion defining an outer surface of the motor portion and extending in the vertical direction to assume a tubular shape; and a plurality of guide vanes arranged in a circumferential direction in the tubular space, and each of which is arranged to extend in a radial direction between an inner surface of the body cover portion and the housing tubular portion. Each of the guide vanes includes a guide vane upper portion arranged on an upper side, and a guide vane lower portion arranged on a lower side of the guide vane upper portion. The guide vane upper portion is inclined to a greater degree with respect to an axial direction than the guide vane lower portion. A lower end of the guide vane is arranged forward of an upper end of the guide vane with respect to a rotation direction of the impeller. The guide vane is arranged to have a smaller thickness at the upper end of the guide vane than at the guide vane lower portion.

The above preferred embodiment of the present invention is able to reduce noise of the blower apparatus while maintaining a high static pressure of the blower apparatus.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, a blower apparatus according to a preferred embodiment of the present invention will be described with reference to the accompanying drawings. It is assumed herein that a direction parallel to a central axis J of a blower apparatus is referred to by the term “axial direction”, “axial”, or “axially”, that directions perpendicular to the central axis J of the blower apparatus are each referred to by the term “radial direction”, “radial”, or “radially”, and that a direction along a circular arc centered on the central axis J of the blower apparatus is referred to by the term “circumferential direction” “circumferential”, or “circumferentially”. It is also assumed herein that an axial direction is a vertical direction, and that a side on which an impeller is arranged with respect to a motor portion is defined as an upper side. The shape of each member or portion and relative positions of different members or portions will be described based on the above assumptions. It should be noted, however, that the above definitions of the vertical direction and the upper side are not meant to restrict in any way the orientation of a blower apparatus according to any preferred embodiment of the present invention when in use.

FIG. 1is a perspective view illustrating the overall structure of a blower apparatus1according to a preferred embodiment of the present invention. The blower apparatus1includes an impeller cover portion14and a body cover portion2arranged in an outer portion thereof. The impeller cover portion14is a member in the shape of a cap, made of a metal, and including an air inlet12defined in a central portion of an upper surface thereof. The body cover portion2includes an upper cover18and a lower cover20. The upper cover18includes a cylindrical portion to which a cylindrical portion of the impeller cover portion14is fitted from outside the upper cover18. An upper flange portion16is defined integrally with a lower end of the cylindrical portion of the upper cover18. The lower cover20includes a lower cylindrical portion24, which includes a plurality of air outlets22defined in a lower portion of an outer circumference thereof, and a lower flange portion26defined integrally with an upper end of the lower cylindrical portion24. The lower cover20is a resin-molded article. The upper and lower flange portions16and26, which are arranged above and below, respectively, are joined to each other and are fastened through screws28. The upper and lower covers18and20are thus joined to each other. More specifically, screw insert holes are defined at several circumferential positions in the upper flange portion16, while screw holes are defined at several circumferential positions in the lower flange portion26such that the screw holes are opposed to the screw insert holes. The screws28are screwed into the screw holes through the screw insert holes.

FIG. 2is a perspective view of the blower apparatus1illustrated inFIG. 1with the impeller cover portion14removed therefrom.FIG. 3is a plan view of the blower apparatus1.FIG. 4is a vertical cross-sectional view of the blower apparatus1taken along line A-A, which passes through a center of the blower apparatus1, inFIG. 3. Parallel oblique lines for details of sections of the blower apparatus1may be omitted.

As illustrated inFIG. 4, an interior space of the blower apparatus1is defined by the impeller cover portion14, the body cover portion2, and a bottom cover30, which is attached to the body cover portion2to cover a lower surface of the body cover portion2. The blower apparatus1further includes an impeller40, which is defined by a centrifugal impeller, and a motor portion50, which has a central axis J extending in the vertical direction, in the interior space.

The impeller40is covered with the impeller cover portion14. The impeller cover portion14includes a cylindrical outer circumferential portion arranged to cover an outer circumference of the impeller40, and an upper surface portion arranged to cover an upper side of an outer edge portion of the impeller40. That is, the impeller cover portion14includes an inner surface arranged to cover the outer circumference of the impeller40and the upper side of the outer edge portion of the impeller40. In addition, the impeller cover portion14includes the air inlet12defined in the central portion of the upper surface thereof. The impeller40is arranged above the motor portion50, is joined to a rotating portion of the motor portion50, and is arranged to rotate to send a gas from above radially outward. The impeller40includes a base plate41, a plurality of rotor blades42arranged in a circumferential direction on an upper surface of the base plate41, and a shroud43in the shape of a curved conical surface, including a central opening, and arranged to join upper ends of the rotor blades42to one another. The base plate41is in the shape of a circular plate. An upper end portion of a rotating shaft51of the motor portion50is joined to a central portion of the base plate41. The impeller40is thus attached to the rotating portion of the motor portion50. The central opening of the shroud43of the impeller40is arranged to be in communication with the air inlet12of the impeller cover portion14.

The motor portion50is, for example, an inner-rotor brushless motor. The motor portion50includes a motor housing including an upper housing portion52, a lower housing portion53, and a housing tubular portion57, and motor components54, which include a rotor portion and a stator portion, accommodated in the motor housing. The rotor portion, which is included in the motor components54, is supported by the rotating shaft51, while the rotating shaft51is rotatably supported by an upper bearing55held on a central portion of the upper housing portion52and a lower bearing56held on a central portion of the bottom cover30. Once the motor portion50is driven, the rotating shaft51is caused to rotate together with the rotor portion, which is included in the motor components54, so that the impeller40, which is joined to the rotating shaft51, is also caused to rotate. Rotation of each of the rotor blades42of the impeller40pushes air in the vicinity of the rotor blade42radially outward, generating negative pressure near a radially inner portion of the rotor blade42, so that external air is sucked in through the air inlet12. The impeller40is caused by the motor portion50to rotate in, for example, a counterclockwise direction in a plan view.

The body cover portion2includes the upper and lower covers18and20. In addition, the body cover portion2, more specifically, the upper cover18thereof, is joined to the impeller cover portion14. The body cover portion2is arranged to cover an outer circumferential surface of the motor portion50. A tubular space60is defined between an inner circumferential surface of the body cover portion2and the outer circumferential surface of the motor portion50. That is, the body cover portion2is joined to the impeller cover portion14, and is arranged to cover an outer circumference of the motor portion50, and define the tubular space60between the body cover portion2and the housing tubular portion57, which defines an outer surface of the motor portion50and extends in the vertical direction to assume a tubular shape. An upper portion of the tubular space60is in communication with a space radially outside of the impeller40inside the impeller cover portion14. Each of the air outlets22of the lower cover20faces a lower portion of the tubular space60. An inner circumferential surface of the upper cover18is a curved surface whose diameter increases with increasing height. An inner circumferential surface of the lower cover20is substantially cylindrical from an upper portion to a middle portion thereof, but is curved at a lower portion thereof, slightly increasing in diameter with decreasing height. As a result, a radial gap in the tubular space60is widest at a top thereof, gradually decreases in width toward a middle portion thereof, and then gradually increases in width from the middle portion toward a bottom thereof. Note that a position at which the radial gap in the tubular space60is narrow corresponds to, for example, a boundary between a guide vane upper portion71and a guide vane lower portion72of each of a plurality of guide vanes70, which will be described below.

The guide vanes70are arranged in the circumferential direction in the tubular space60. In the present preferred embodiment, the guide vanes70are arranged at regular intervals. More specifically, the guide vanes70are arranged at regular intervals in the circumferential direction in the tubular space60, and each guide vane70is arranged to extend in a radial direction between an inner surface of the body cover portion2and the housing tubular portion57. The guide vanes70are integrally molded with the upper housing portion52. Each of the guide vanes70includes the guide vane upper portion71, which is arranged on the upper side, and the guide vane lower portion72, which is arranged on the lower side of the guide vane upper portion71. The guide vane upper portion71is inclined to a greater degree with respect to the axial direction than the guide vane lower portion72. A lower end of each guide vane70is arranged forward of an upper end of the guide vane70with respect to a rotation direction of the impeller40. Air discharged by the impeller40is thus smoothly guided downward along the guide vane70. Further, a reduction in noise can be achieved while static pressure of air guided between the guide vanes70is maintained. The lower end of each guide vane70is arranged forward of the upper end of the guide vane70with respect to the rotation direction of the impeller40. The guide vanes70are thus able to guide a wind flowing along the rotation direction of the impeller40smoothly axially downward. Further, an improvement in air blowing efficiency of the blower apparatus1can be achieved. Note that the circumferential positions of an upper end and a lower end of a radially outer end of each guide vane70may be compared with each other to determine which of the upper and lower ends of the guide vane70lies forward of the other with respect to the rotation direction. Here, it is preferable that the lower end is arranged forward of the upper end with respect to the rotation direction of the impeller40. For example, also in a case where the guide vane70is inclined with respect to the radial direction when viewed from axially above, and in a case where an upper surface of the guide vane70is inclined with respect to a direction perpendicular to the axial direction when viewed in the radial direction, the circumferential positions of the upper and lower ends of the radially outer end of the guide vane70may be compared with each other. In addition, a lower end70bof at least one of the guide vanes70is arranged above a lower end of the housing tubular portion57. Thus, when compared to a case where the lower end70bof each guide vane70is arranged at a level the same as or lower than that of the lower end of the housing tubular portion57, channel resistance for air flowing between the guide vanes70can be reduced, resulting in improved air blowing efficiency of the blower apparatus1. In the present preferred embodiment, the axial position of the lower end of the housing tubular portion57and the axial position of a lower end of the lower cylindrical portion24substantially coincide with each other. That is, the axial position of the lower end of the housing tubular portion57substantially coincides with an axial position at which each air outlet22is defined. Accordingly, when the lower end70bof each guide vane70is arranged at a level higher than that of the lower end of the housing tubular portion57, the guide vane70is not defined in the vicinity of each air outlet22. This leads to a reduction in pressure of air flowing in the tubular space60and a reduction in air resistance in the vicinity of the air outlet22. Accordingly, an improvement in the air blowing efficiency of the blower apparatus1is achieved.

The guide vane upper portion71is arranged to curve rearward with respect to the rotation direction with increasing height. That is, rotation of the impeller40causes an air current whirling in the same direction as the rotation direction of the impeller40, and this air current can be smoothly taken in and guided into a downward flow. Thus, the whirling air current sent from the impeller40can be guided downward.

FIG. 5illustrates the blower apparatus1when the upper cover18and the lower cover20are cut along line B-B inFIG. 3.FIG. 6illustrates two of the guide vanes70illustrated inFIG. 5in an enlarged form. Referring toFIG. 6, a forward surface of the guide vane upper portion71with respect to the rotation direction includes a forward upper curved surface71x1arranged on the upper side, and a forward lower curved surface71x2arranged on the lower side. On the forward side of the guide vane upper portion71of the guide vane70with respect to the rotation direction of the impeller40, the forward upper curved surface71x1and the forward lower curved surface71x2, which have different radii of curvature, are arranged continuously. The forward upper curved surface71x1has a radius of curvature Rx1greater than a radius of curvature Rx2of the forward lower curved surface71x2(Rx1>Rx2). This allows air flowing along a forward surface of the guide vane70with respect to the rotation direction to smoothly flow along the forward surface of the guide vane70with respect to the rotation direction. This leads to improved air blowing efficiency of the blower apparatus1, resulting in a reduction in noise. Here, a forward upper curved surface center x1is a center of curvature of the forward upper curved surface71x1, while a forward lower curved surface center x2is a center of curvature of the forward lower curved surface71x2.

On the rearward side of the guide vane upper portion71of the guide vane70with respect to the rotation direction of the impeller40, a curved surface71y1having a radius of curvature Ry1smaller than that of the curved surface71x1is arranged (Rx1>Ry1). That is, a rearward surface of the guide vane upper portion71with respect to the rotation direction includes a rearward curved surface71y1arranged to curve rearward with respect to the rotation direction with increasing height. The radius of curvature Ry1of the rearward curved surface71y1is smaller than the radius of curvature Rx1of the forward upper curved surface71x1. In other words, the forward upper curved surface71x1is arranged to curve more gently than the rearward curved surface71y1. Thus, the forward upper curved surface71x1is able to guide air having a forward whirl component with respect to the rotation direction due to the rotation of the impeller40while reducing the likelihood of a separation of the air from the guide vane70. In addition, the rearward curved surface71y1is able to guide air having a forward whirl component with respect to the rotation direction of a similar magnitude so that the air can smoothly flow downward along the guide vane70. Here, a rearward curved surface center y1is a center of curvature of the rearward curved surface71y1.

A center of the forward upper curved surface71x1is arranged forward of a center of the rearward curved surface71y1with respect to the rotation direction. That is, when viewed in the radial direction, an axial midpoint of the forward upper curved surface71x1is arranged forward of an axial midpoint of the rearward curved surface71y1with respect to the rotation direction. More specifically, each guide vane70is arranged to have a circumferential width greater than a half of a circumferential width of an interspace between adjacent ones of the guide vanes70. Thus, the guide vane70has a sufficient circumferential width to allow the forward and rearward curved surfaces of the guide vane70with respect to the rotation direction to have more preferable values of curvature. In addition, the guide vane70is arranged to have a smaller thickness at a guide vane upper end70athan at the guide vane lower portion72. Thus, air traveling forward with respect to the rotation direction of the impeller40can be smoothly guided from the guide vane upper end70ato the forward upper curved surface71x1. Further, as the air travels downward and the thickness of the guide vane70increases, the air is smoothly guided axially downward.

On the forward side with respect to the rotation direction of the impeller40, the guide vane lower portion72of each guide vane70includes a forward flat surface72x1continuous with the curved surface71x2, and, below the forward flat surface72x1, a slanting surface72x2arranged to slant rearward with respect to the rotation direction with decreasing height. That is, a forward surface of the guide vane lower portion72with respect to the rotation direction includes the slanting surface72x2arranged to slant rearward with respect to the rotation direction with decreasing height. Thus, air which has been guided along the forward surface of the guide vane70with respect to the rotation direction is smoothly guided along the slanting surface72x2. Accordingly, the slanting surface72x2reduces the likelihood that turbulence will occur in the vicinity of the lower end of the guide vane70when the air flows downward from the lower end of the guide vane70. Therefore, the slanting surface72x2contributes to preventing a reduction in the air blowing efficiency of the blower apparatus1. In addition, a rearward surface of the guide vane lower portion72with respect to the rotation direction includes a rearward flat surface72y1continuous with the rearward curved surface71y1, and a slanting surface72y2arranged to slant forward with respect to the rotation direction with decreasing height. Thus, air which has been guided along a rearward surface of the guide vane70with respect to the rotation direction is smoothly guided along the slanting surface72y2. Accordingly, the slanting surface72y2reduces the likelihood that turbulence will occur in the vicinity of the lower end of the guide vane70when the air flows downward from the lower end of the guide vane70. Therefore, the slanting surface72y2contributes to preventing a reduction in the air blowing efficiency of the blower apparatus1.

Each of the plurality of guide vanes70is arranged to axially overlap in part with an adjacent one of the guide vanes70. Specifically, as illustrated inFIG. 5, a tip portion of the guide vane upper portion71of each guide vane70is arranged to axially overlap with the guide vane upper portion71and the guide vane lower portion72of the guide vane70which is adjacent to and rearward of the guide vane70with respect to the rotation direction of the impeller40. The above structure allows the guide vanes70to more efficiently take in air sent from the impeller40and guide the air into the downward flow.

An intervane space between every adjacent ones of the plurality of guide vanes70, which are arranged at regular intervals in the circumferential direction in the tubular space60, is arranged to be narrowest at a tip of the guide vane upper portion71of the guide vane70and widest at a lower end of the guide vane lower portion72of the guide vane70when measured in a direction perpendicular to a direction in which the gas flows through the air channel between the adjacent guide vanes70.

Once the motor portion50is driven in the blower apparatus1having the above-described structure, the impeller40is caused to rotate to take in external air through the air inlet12of the impeller cover portion14and discharge the air radially outward as a swirl flow, so that the air is guided to an inner surface of the cylindrical outer circumferential portion of the impeller cover portion14. Further, the air current sent from the impeller40is guided into the tubular space60to pass through the intervane space between the adjacent guide vanes70, so that the swirl flow is guided into an axial flow.

At this time, each guide vane70is able to effectively take the swirl flow from the impeller40into the interspace between the guide vanes70through the guide vane upper portion71arranged in the upper portion thereof. In addition, the thickness of the guide vane upper portion71varies along the direction in which the air flows. Specifically, the forward upper curved surface71x1and the forward lower curved surface71x2, which have different radii of curvature, are arranged on the forward side of the guide vane70with respect to the rotation direction, and the one rearward curved surface71y1is arranged on the rearward side of the guide vane upper portion71with respect to the rotation direction, and this enables the air current to be efficiently guided along the surface of the guide vane70without a separation of the air current. In particular, it has been observed that, when the radii of curvature Rx1and Rx2of the forward upper curved surface71x1and the forward lower curved surface71x2, respectively, on the forward side of the guide vane upper portion71with respect to the rotation direction meet the relationship Rx1>Rx2, and the radius of curvature Ry1of the rearward curved surface71y1on the rearward side of the guide vane upper portion71with respect to the rotation direction meets the relationship Rx1>Ry1, the air flow in the tubular space60is improved to achieve a significant improvement in efficiency.

In addition, the radial gap in the tubular space60is narrowest near the boundary between the guide vane upper portion71and the guide vane lower portion72of each guide vane70. More specifically, in the tubular space60, the radial gap between the outer surface of the motor portion50and the inner surface of the body cover portion2is arranged to continuously decrease in width from the axially upper side toward an axial middle portion thereof, and continuously increase in width from the axial middle portion toward the axially lower side. Thus, air which has flowed into the tubular space60is compressed in the vicinity of the boundary between the guide vane upper portion71and the guide vane lower portion72due to an increase in channel resistance, and the air is thereafter decompressed to form a gentle air flow due to a gradual increase in the width of the radial gap as the air travels downward along the guide vane lower portion72. The air is thus discharged with a reduced likelihood of a separation of the air. In particular, the above effect is promoted by a gradual increase in the width of the interspace between the adjacent guide vanes70at a lower portion of the guide vane lower portion72.

While a preferred embodiment of the present invention has been described above, it will be understood that the present invention is not limited to the above-described preferred embodiment, and that a variety of modifications are possible without departing from the scope of the present invention as claimed below.

FIG. 7is a diagram illustrating guide vanes70A according to a preferred modification of the present preferred embodiment. The same reference characters as used for portions of the guide vanes70illustrated inFIG. 6will be used for portions of the guide vanes70A illustrated inFIG. 7. InFIG. 6, each of the guide vanes70arranged in the tubular space60is arranged to axially overlap in part with an adjacent one of the guide vanes70. Note, however, that each of the guide vanes70may not necessarily be arranged to axially overlap with the adjacent one of the guide vanes70. The guide vanes70A illustrated inFIG. 7are not arranged to axially overlap with each other. Accordingly, the guide vanes70A can be molded using molds which are slid in the vertical direction. That is, resin-molding molds having a simple structure can be used to mold the guide vanes70A. That is, a forward end portion of each guide vane70A with respect to the rotation direction is preferably arranged rearward of a rearward end portion of a forwardly adjacent one of the guide vanes70A with respect to the rotation direction. Thus, the adjacent ones of the guide vanes70A are arranged not to axially overlap with each other. Accordingly, the guide vanes70A can be molded using molds which are slid in the vertical direction. Therefore, the guide vanes70A can be molded using simple molds, which leads to an improved mass productivity of the blower apparatus1.

Meanwhile, in the case where the guide vanes70are arranged to axially overlap in part with one another as illustrated inFIG. 6, it may be so arranged that alternate ones of the guide vanes70are integrally defined with the upper housing portion52while the other alternate ones of the guide vanes70are integrally defined with the upper cover18.

Further, although, in the above-described preferred embodiment, the guide vane lower portion72of each of the plurality of guide vanes70arranged in the tubular space60is arranged to extend axially downward, this is not essential to the present invention. The guide vane lower portion72may be arranged to extend downward and be angled with respect to the axial direction toward the direction in which the guide vane upper portion71is curved. When each guide vane70is shaped in such a manner, an effect similar to the effect of the above-described preferred embodiment can be obtained even if the length of the guide vane upper portion71is reduced, and therefore, the length of each guide vane70can be reduced to achieve a reduction in the size of the blower apparatus1as a whole.

Although, in the above-described preferred embodiment, the impeller40caused by the motor portion50to rotate is a centrifugal impeller, this is not essential to the present invention. A mixed flow impeller may alternatively be used. In this case, the mixed flow impeller is joined to the rotating portion of the motor portion, and is caused by the motor portion to rotate to suck a gas from above and send the gas radially outward while guiding the gas along slanting surfaces of the mixed flow impeller.

FIG. 8is a perspective view of a vacuum cleaner100. The vacuum cleaner100includes the blower apparatus1according to the present preferred embodiment. Thus, the vacuum cleaner100is able to achieve reduced noise while maintaining a static pressure of air flowing in the vacuum cleaner100.

Although the blower apparatus according to the above-described preferred embodiment of the present invention is used in a vacuum cleaner which utilizes air sucked by the blower apparatus, this is not essential to the present invention. A blower apparatus according to a preferred embodiment of the present invention may be used in, for example, a hair drier which utilizes air sent out by the blower apparatus.

Blower apparatuses according to preferred embodiments of the present invention are suitable for use in, for example, electric vacuum cleaners, hair driers, and the like.