US20060062669A1

US20060062669A1 - Blower

Info

Publication number: US20060062669A1
Application number: US11/223,113
Authority: US
Inventors: Tomomasa Nishikawa; Junichi Sudou; Masahiro Miura
Original assignee: Individual
Current assignee: Koki Holdings Co Ltd
Priority date: 2004-09-17
Filing date: 2005-09-12
Publication date: 2006-03-23
Also published as: JP2006083831A; CN1749576A

Abstract

A casing is provided with an outer frame defining an internal space and with a partition dividing the internal space into a fan housing and a motor housing. The outer frame is formed with an inlet and an outlet allowing fluid communication between the fan housing and an exterior. The imaginary rotational axis of the fan is substantially coincident with the imaginary central axis of the inlet. The fan is positioned between the inlet and the motor. The fan includes a mount portion mounted on the drive shaft, a generally circular base plate formed integrally with the mount portion, and a plurality of vanes protruding from the base plate toward the inlet. The outer frame includes a slanted portion adjacent to the inlet and slanted in such a manner that a distance between the slanted portion and the imaginary central axis is gradually reduced in a direction toward the inlet.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention
The present invention relates to a blower, and more particularly, to such portable blower having a blower mode to blow away dust and the like, and a vacuum mode to suck in air to perform dust collection or the like.
2. Description of Related Art
One conventional blower is described in Japanese patent-application publication No. 2002-339898. FIG. 7 shows the structure of a conventional blower 101. As shown in FIG. 7, the blower 101 includes an electric motor 108, a casing 105 having an inlet 103 and an outlet 104, and a fan 106 disposed inside the casing 105. When the motor 108 drives the fan 106 to rotate, the fan 106 draws air through the inlet 103 and blows the air out through the outlet 104.
The blower 101 can be used to perform blowing operations by attaching a nozzle (not shown) to the outlet 104 and blowing fallen leaves, wood chips, and the like with the air emitted through the nozzle. The blower 101 can also be used for suction operations by attaching a dust-collecting bag (not shown) to the outlet 104 and attaching a nozzle or a hose (not shown) to the inlet 103 so that small wood chips or the like can be drawn through the inlet 103 and collected in the bag.
As shown in FIG. 7, the casing 105 of the blower 101 is configured of three casing segments 105A, 105B, and 105C. In addition to the inlet 103 and outlet 104, the casing 105 has a motor housing for accommodating the motor 108, and a fan housing for accommodating the fan 106. The motor housing is defined by the casing segments 105A and 105B, while the fan housing is defined by the casing segments 105B and 105C, which are joined by a fastening member 117. A handle 102 is provided on the casing segment 105A for enabling a user to grip the blower 101.
The inlet 103 is formed on the casing segment 105C and protrudes along the rotational axis of the fan 106 in a direction away from the motor 108. The inlet 103 is positioned so as to be substantially coaxial with the rotational axis of the fan 106. The inlet 103 includes ribs 103B to prevent large foreign matter from entering the casing 105, and openings 103 a formed between the ribs 103B and in fluid communication with the fan housing.
The outlet 104 is also in fluid communication with the fan housing and is formed in a cylindrical shape by the casing segments 105B and 105C that protrude tangentially from the fan 106. An attachment portion 113 is provided on the protruding end of the casing segments 105B and 105C. For blowing operations, the nozzle or hose is attached to the attachment portion 113.
The fan 106 is positioned between the inlet 103 and the motor 108. The fan 106 includes a mount portion 106A that is mounted on a drive shaft 107 of the motor 108, a base plate 106B that is substantially circular or disc-shaped and formed integrally with the mount portion 106A, and a plurality of vanes 106C connected with the mount portion 106A and the base plate 106B and positioned on the inlet 103 side of the base plate 106B.

SUMMARY

In the conventional blower 101 described above, the casing segment 105C near the inlet 103 is formed to extend substantially orthogonal to the rotational axis of the fan 106. The inlet 103 is disposed on the casing segment 105C so that the central axis of the inlet 103 is substantially coincident (coaxial) with the rotational axis of the fan 106.
With the above-described construction, air is drawn into the fan housing through the inlet 103, as indicated by an arrow A11. The air then passes through spaces between the mount portion 106A of the fan 106 and the inner surface of the casing segment 105C, as indicated by arrows A12. However, since the casing 105 near the inlet 103 extends orthogonal to the rotational axis of the fan 106, as described above, the spaces between the mount portion 106A and the inner surface of the casing segment 105C are small and produce a large flow resistance.
Further, after passing through these spaces in the direction of flow indicated by the arrows A12, the air changes direction to flow perpendicular to the rotational axis of the fan 106 along the inner surface of the casing segment 105C, as indicated by arrows A13, producing a large flow resistance.
If the motor 108 rotates at an abnormal speed due to a supplied voltage greater than the rated voltage, an abnormally large centrifugal force will be applied to the fan 106, causing the fan 106 to deform so that the base plate 106B and the vanes 106C gravitate toward the casing segment 105B on the motor 108 side. When this occurs, the base plate 106B of the fan 106 contacts the inner surface of the casing segment 105B, thereby decelerating or stopping the abnormal rotation of the fan 106. However, since the contact with the base plate 106B of the fan 106 applies a large force to the casing segment 105B, it is necessary to increase the thickness and enhance the strength of the casing segment 105B. These changes to the casing segment 105B increase the overall weight of the blower 101, making the blower 101 more difficult to operate.
In view of the foregoing, it is an object of the present invention to provide a blower having a large suction capacity and a large blowing capacity. It is another object of the present invention to provide a blower that is easy to operate and that can reduce the amount of deformation in the fan during abnormal rotations and the like.
In order to attain the above and other objects, according to one aspect, the present invention provides a blower. The blower includes a casing, a motor, and a fan. The casing is provided with an outer frame defining an internal space and with a partition dividing the internal space into a fan housing and a motor housing. The outer frame is formed with an inlet allowing fluid communication between the fan housing and an exterior for sucking fluid into the fan housing therethrough, and an outlet allowing fluid communication between the fan housing and the exterior for discharging fluid from the fan housing to the exterior therethrough. The inlet has an imaginary central axis. The motor is disposed in the motor housing and has a drive shaft that extends into the fan housing. The fan is disposed in the fan housing and is rotatable about an imaginary rotational axis by the motor. The imaginary rotational axis is substantially coincident with the imaginary central axis of the inlet. The fan is positioned between the inlet and the motor. The fan includes a mount portion mounted on the drive shaft, a generally circular base plate formed integrally with the mount portion, and a plurality of vanes protruding from the base plate toward the inlet. The outer frame includes a slanted portion adjacent to the inlet and slanted in such a manner that a distance between the slanted portion and the imaginary central axis is gradually reduced in a direction toward the inlet.
According to another aspect, the present invention provides a blower. The blower includes a casing, a motor, and a fan. The casing is provided with an outer frame defining an internal space and with a partition dividing the internal space into a fan housing and a motor housing. The outer frame is formed with an inlet allowing fluid communication between the fan housing and an exterior for sucking fluid into the fan housing therethrough, and an outlet allowing fluid communication between the fan housing and the exterior for discharging fluid from the fan housing to the exterior therethrough. The inlet has an imaginary central axis. The motor is disposed in the motor housing and has a drive shaft that extends into the fan housing. The fan is disposed in the fan housing and is rotatable about an imaginary rotational axis by the motor. The imaginary rotational axis is substantially coincident with the imaginary central axis of the inlet. The fan is positioned between the inlet and the motor. The fan includes a mount portion mounted on the drive shaft, a generally circular base plate formed integrally with the mount portion, and a plurality of vanes protruding from the base plate toward the inlet. When the fan deforms during rotation, the base plate is contactable with the partition and the plurality of vanes is contactable with the outer frame.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and advantages of the invention will become more apparent from reading the following description of the embodiments taken in connection with the accompanying drawings in which:
FIG. 1 is a front view with a partial cross-section showing a blower according to an embodiment of the present invention;
FIG. 2 is a side view with a partial cross-section showing the blower according to the embodiment;
FIG. 3 is a perspective view showing a fan of the blower according to the embodiment;
FIG. 4 is a plan view showing the fan of the blower according to the embodiment;
FIG. 5 is a cross-sectional view of the fan taken along a line V-V in FIG. 4;
FIG. 6 is an enlarged cross-sectional view illustrating the relationship between a casing and the fan of the blower according to the embodiment; and
FIG. 7 is a side view with a partial cross-section showing a conventional blower.

DETAILED DESCRIPTION OF THE EMBODIMENTS

A blower 1 according to an embodiment of the present invention will be described with reference to FIGS. 1 through 6. The embodiment pertains to a compact and light-weight portable blower also serving as a dust collector. The blower 1 includes a casing 5 formed with an inlet 3 for sucking in air and an outlet 4 for blowing out air. The casing 5 has a handle 2 to be gripped by a user's hand.
An electric motor 8 (FIG. 2) and a centrifugal fan 6 are installed in the casing 5. The centrifugal fan 6 is drivingly coupled to the electric motor 8 via a drive shaft 7 (FIG. 2) described later, and is rotated by the rotation of the electric motor 8. Air is sucked into the casing 5 through the inlet 3, and is blown out through the outlet 4 by the centrifugal force established by the rotation of the centrifugal fan 6. The outlet 4 is in fluid communication with a fan housing space 5 g formed in the casing 5, and is located on a tangential line of a base plate 6B (FIG. 2) of the centrifugal fan 6 disposed in the fan housing space 5 g. The outlet 4 is configured in a cylindrical shape by casing segments 5B and 5C (FIG. 2) of the casing 5.
A portion around the outlet 4 serves as an attachment portion 13 to which accessories such as a dust collection bag (not shown) or a nozzle 20 is selectively attached. The inlet 3 has a generally arcuate shape and is positioned in confrontation with and coaxially with the centrifugal fan 6.
As shown in FIG. 1, when the blower 1 is used in a blower mode to blow away dusts, fallen leaves, wood chips, etc., the nozzle 20 or a hose (not shown) is attached to the attachment portion 13 of the casing 5, while nothing is attached to the inlet 3. Blowing operation can be performed by directing the tip of the nozzle 20 toward the dusts, small wood chips or other such objects and blowing out pressurized air through the nozzle 20. Incidentally, even without the nozzle 20 blowing operation can still be performed by directing the outlet 4 toward the target and blowing air out from the outlet 4.
Furthermore, when the blower 1 is to be operated in a suction mode to collect dusts, wood chips, etc., the dust collection bag (not shown) is attached to the attachment portion 13 of the casing 5, while a nozzle or a hose (not shown) is attached to the inlet 3. Suction operation can be performed by directing the tip of the nozzle or the hose toward dusts, small wood chips, or other such objects and then sucking in the objects into the dust collection bag.
The construction of the blower 1 is described in greater detail with reference to FIG. 2. As shown in FIG. 2, the casing 5 is configured of three casing segments 5A, 5B, and 5C. The mutually opposing casing segment 5B and casing segment 5C define the fan housing space 5 g for installing therein the centrifugal fan 6. The casing segment 5B includes a circular partition 51 partitioning the fan housing space 5 g from a motor housing space 5 f (described later) and a peripheral wall 52. The casing segment 5B has a bearing holder 53 for accommodating a bearing 18. The centrifugal fan 6 is concentrically mounted on the drive shaft 7.
Note that part of the casing segments 5A, 5B, and 5C serves as an outer frame (outer casing) which defines an internal space therein. The partition 51 divides the internal space into the fan housing space 5 g and the motor housing space 5 f.
A drive shaft through-hole 5 k is formed at the center of the circular partition 51 and within the bearing holder 53 for allowing the drive shaft 7 to extend therethrough into the fan housing space 5 g.
The casing segment 5A is connected to the casing segment 5B with a bolt or the like at a position opposite to the fan housing space 5 g with respect to the partition 51. The casing segment 5A has generally cylindrical cup shape and is coaxial with the centrifugal fan 6. A bottom of the cup serves as an end wall of the casing 5, and an open end of the casing segment 5A is fitted to the casing segment 5B. Thus, the casing segment 5A defines therein a motor housing space 5 f where the electric motor 8 is supported. The partition 51 separates the fan housing space 5 g from the motor housing space 5 f. A bearing 19 is supported at a distal end of the casing segment 5A. Thus, the drive shaft 7 is rotatably supported to the casing 5 through these bearings 18 and 19.
The casing segment 5C is coupled to the casing segment 5B by a fastening member 17 at a parting face 5M extending in a direction perpendicular to the axis of the drive shaft 7. The casing segment 5C includes an end wall section in confrontation with the partition 51 of the casing segment 5B, and a peripheral wall 54 corresponding to the peripheral wall 52 of the casing segment 5B. By the combination of the casing segment 5B and the casing segment 5C, single fan housing space 5 g is provided. More specifically, the partition 51, the peripheral wall 52 of the casing segment 5B, and the end wall section and the corresponding peripheral wall 54 of the casing segment 5C provide the fan housing space 5 g.
The above-described inlet 3 is formed in the casing segment 5C coaxially with the centrifugal fan 6. A sleeve like protrusion 56 protrudes from the inlet 3 in the axial direction of the fan 6. Thus, the nozzle or other accessory is detachably attached to the sleeve like protrusion 56.
As described above, the inlet 3 is formed at an axial end of the casing segment 5C and protrudes along the rotational axis RA of the fan 6 in a direction away from the motor 8. The inlet 3 has an imaginary central axis CA which is substantially coincident with the rotational axis RA of the fan 6. In other words, the inlet 3 is substantially coaxial with the fan 6. Ribs 3B are provided in the inlet 3 to prevent large foreign matter from entering the casing 5. Openings 3 a are formed between the ribs 3B and are in fluid communication with the fan housing space 5 g.
As shown in FIGS. 2 and 6, the casing 5 (the casing segment 5C) near the inlet 3 has a slanted portion 55 that slants away from the motor 8 in a direction toward the central axis CA. In other words, the slanted portion 55 is positioned adjacent to the inlet 3 and slanted in such a manner that a distance D between the slanted portion 55 and the central axis CA is gradually reduced in a direction toward the inlet 3. Further, the slanted portion 55 has a curved inner surface 5D.
As shown in FIGS. 3 and 4, the centrifugal fan 6 includes a mount portion 6A, the base plate 6B, and a plurality of vanes 6C. The base plate 6B is substantially circular or disc-shaped and is formed integrally with the mount portion 6A. The drive shaft 7 is fixed to the mount portion 6A by force-fitting or using fasteners such as a nut. The plurality of vanes 6C protrudes from one surface 61 of the base plate 6B. The plurality of vanes 6C is also connected with the mount portion 6A. The base plate 6B has an opposite surface 62 positioned in direct confrontation with the circular partition 51 (FIG. 2) of the casing segment 5B.
A plurality of through-holes 63 is formed in the base plate 6B. Each through-hole 63 is positioned between neighboring vanes 6C, and is positioned in an imaginary circle whose center is coincident with the axis of the drive shaft 7.
As shown in FIG. 4, the vanes 6C are slanted with respect to the radial direction of the fan 6. The vanes 6C curl to be convex toward a rotational direction R of the fan 6 (the rotational direction R is counterclockwise in FIGS. 3 and 4).
As shown in FIGS. 2, 3, and 6, the vanes 6C have protruding portions 6D which protrude away from the motor 8 (to the right in FIG. 2) at an intermediate position in the radial direction.
As shown in FIGS. 2 and 3, each vane 6C has a first edge 64 and a second edge 65 which extend on a side opposite from the motor 8. As shown in FIG. 2, the first edge 64 slants away from the motor 8 in a direction toward the central axis CA. In other words, the first edge 64 is slanted in such a manner that a distance between the first edge 64 and the central axis CA is gradually reduced in a direction toward the inlet 3. Hence, the first edge 64 approximately follows the inner surface of the slanted portion 55. That is, the first edge 64 extends substantially parallel to the slanted portion 55 of the casing 5.
The second edge 65 is slanted in such a manner that a distance between the second edge 65 and the central axis CA is gradually increased in a direction toward the inlet 3. Thus the first edge 64 and the second edge 65 join together to form a tip portion 66 (FIGS. 3 and 5).
Next, the flow of air in the blower 1 will be described with reference to FIG. 2. As the fan 6 is driven to rotate, air is drawn into the casing 5 through the inlet 3 by the fan 6 in a flow indicated by an arrow A1. The flow of air passes through the openings 3 a in a direction indicated by arrows A2, gradually changing direction toward a direction orthogonal to the rotational axis RA of the fan 6, so as to pass between the vanes 6C in a curved path following the curved inner surface 5D of the slanted portion 55 of the casing segment 5C. As the fan 6 rotates, the air flows radially outwardly through the casing segments 5B and 5C and is blown out through the outlet 4 in the direction indicated by arrows A3.
As described above, the inner surface 5D of the casing segment 5C near the inlet 3 has a curved shape that slopes away from the motor 8 in a direction toward the central axis CA of the inlet 3 (FIGS. 2 and 6). Therefore, it is possible to increase a space 5 s between the inner surface 5D of the casing segment 5C and the mount portion 6A of the fan 6, through which air from the inlet 3 passes into the fan housing space 5 g, thereby reducing the flow resistance on the airflow. Further, since the inner surface 5D of the casing segment 5C has a curved surface that allows the flow of air to gradually change directions toward a direction orthogonal to the rotational axis RA of the fan 6, the flow resistance on the airflow can be decreased, thereby improving the suction capacity and blowing capacity of the blower 1. Also, because the first edge 64 of the vanes 6C slopes along the curved inner surface 5D and because the vanes 6C are positioned within the space 5 s described above, the air suction capacity and blowing capacity can be improved.
If the motor 8 rotates at an abnormal speed due to a supplied voltage higher than the rated voltage, a great centrifugal force is applied to the fan 6, causing the fan 6 to deform. However, the blower 1 according to the present embodiment can suppress this deformation, as described below.
As shown in FIG. 4, the vanes 6C of the fan 6 are slanted with regard to the radial direction of the fan 6 and bend from an approximately central point CP of the vanes 6C.
Therefore, as shown in FIG. 5, a space 6 s is formed between an outermost portion 6M of the vanes 6C in the radial direction and the mount portion 6A. Here, FIG. 5 is a cross-sectional view along a line V-V in FIG. 4. Although center of gravity CG in the outermost portion 6M of the vanes 6C lies in the approximate center with respect to the axial direction RA of the fan 6, the space 6 s is formed between the outermost portion 6M of the vanes 6C and the mount portion 6A, and the outermost portion 6M is connected (coupled) only with the base plate 6B at a connection portion 6N. Accordingly, when the fan 6 rotates, a centrifugal force CF is applied to the outermost portion 6M, thereby producing a moment M that attempts to slant the outermost portion 6M in a radially outward direction about the connection portion 6N.
Therefore, if the motor 8 rotates at an abnormal speed or the like, causing a large moment to be applied to the outermost portion 6M of the vanes 6C, the base plate 6B also deforms toward the motor 8 about a connection portion 6P at which the base plate 6B connects to the mount portion 6A. Hence, as shown in FIG. 6, both the base plate 6B and the vanes 6C deform greatly.
Further, centrifugal force acts on the vanes 6C, which are slanted with respect to the radial direction of the fan 6 (FIG. 4). Hence, the vanes 6C may deform toward the radially outward direction of the fan 6. Because of this deformation and the deformation described earlier the fan 6 deforms toward the motor 8 as indicated by an arrow A4 (FIG. 2) during the abnormal rotation.
As shown in FIG. 6, when the fan 6 deforms toward the motor 8 due to the abnormal rotation, the first edge 64 of the vanes 6C contacts the inner surface 5D of the slanted portion 55. More specifically, the tip portion 66 contacts the slanted portion 55. Hence, this construction can suppress deformation of the vanes 6C and can thereby reduce the abnormal deformation, damage, and the like incurred by the fan 6.
During this deformation, the base plate 6B also contacts a surface 5H of the partition 51. Therefore, the fan 6 contacts the inner surface of the casing 5 at two locations, thereby distributing the load applied to the casing 5. As a result, it is not necessary to increase the thickness of the casing 5 so that the casing 5 can withstand contact with the fan 6. Hence, the weight of the components are not increased, thereby achieving a blower that is lightweight and easy to operate.
Further, even when the vanes 6C are damaged or when cracks are formed at the connection portion between the vanes 6C and the mount portion 6A due to the abnormal rotation, the vanes 6C contact the inner surface 5D of the casing 5 near the inlet 3. Therefore, a broken piece or fragment of the fan 6 does not come off and impact the casing 5.
While the invention has been described in detail with reference to the specific embodiment thereof, it would be apparent to those skilled in the art that various changes and modifications may be made therein without departing from the spirit of the invention.

Claims

1. A blower comprising:

a casing provided with an outer frame defining an internal space and with a partition dividing the internal space into a fan housing and a motor housing, the outer frame being formed with an inlet allowing fluid communication between the fan housing and an exterior for sucking fluid into the fan housing therethrough, and an outlet allowing fluid communication between the fan housing and the exterior for discharging fluid from the fan housing to the exterior therethrough, the inlet having an imaginary central axis;

a motor disposed in the motor housing and having a drive shaft that extends into the fan housing; and

a fan disposed in the fan housing and rotatable about an imaginary rotational axis by the motor, the imaginary rotational axis being substantially coincident with the imaginary central axis of the inlet, the fan being positioned between the inlet and the motor, the fan comprising:

a mount portion mounted on the drive shaft;

a generally circular base plate formed integrally with the mount portion; and

a plurality of vanes protruding from the base plate toward the inlet,

wherein the outer frame comprises a slanted portion adjacent to the inlet and slanted in such a manner that a distance between the slanted portion and the imaginary central axis is gradually reduced in a direction toward the inlet.

2. The blower according to claim 1, wherein each vane has an edge on a side opposite from the motor; and

wherein at least part of the edge is slanted in such a manner that a distance between the at least part of the edge and the imaginary central axis is gradually reduced in a direction toward the inlet, allowing the at least part of the edge to be substantially parallel to the slanted portion.

3. The blower according to claim 1, wherein each vane has an edge on a side opposite from the motor; and

wherein the edge and the slanted portion have a space therebetween allowing the edge and the slanted portion to contact each other when the fan deforms during rotation.

4. The blower according to claim 3, wherein the deformation of the fan is caused when the motor rotates at an abnormal speed.

5. The blower according to claim 4, wherein the motor rotates at the abnormal speed when a voltage greater than a rated voltage is applied to the motor.

6. The blower according to claim 1, wherein the fan defines a radial direction; and

wherein the plurality of vanes extends in a direction slanted with respect to the radial direction.

7. A blower comprising:

a mount portion mounted on the drive shaft;

a generally circular base plate formed integrally with the mount portion; and

a plurality of vanes protruding from the base plate toward the inlet,

wherein, when the fan deforms during rotation, the base plate is contactable with the partition and the plurality of vanes is contactable with the outer frame.

8. The blower according to claim 7, wherein the fan defines a radial direction; and

9. The blower according to claim 7, wherein the deformation of the fan is caused when the motor rotates at an abnormal speed.

10. The blower according to claim 9, wherein the motor rotates at the abnormal speed when a voltage greater than a rated voltage is applied to the motor.

11. The blower according to claim 7, wherein the outer frame comprises a slanted portion adjacent to the inlet and slanted in such a manner that a distance between the slanted portion and the imaginary central axis is gradually reduced in a direction toward the inlet.

12. The blower according to claim 11, wherein each vane has an edge on a side opposite from the motor; and

13. The blower according to claim 12, wherein the edge comprises another part slanted in such a manner that a distance between the another part of the edge and the imaginary central axis is gradually increased in a direction toward the inlet;

wherein the at least part of the edge and the another part of the edge join together to form a tip portion; and

wherein the tip portion is contactable with the slanted portion.