Fan for handheld blower

Abstract

A fan is disclosed that includes a hub and a plurality of blades extending radially outward from the hub and spaced circumferentially about the hub. The plurality of blades includes a reference blade, a first blade, and a second blade. The reference blade is disposed about the hub in the circumferential direction after the first blade. The second blade is disposed after the reference blade in the circumferential direction. The first blade is circumferentially spaced from the reference blade by a first distance. The second blade is circumferentially spaced from the reference blade by a second distance. The first distance is greater than the second distance.

Description

Background Art

[0001] The present disclosure relates to handheld blowers and, more particularly, to fans for handheld blowers. Utility Model Content

[0002] In an independent aspect, the present disclosure provides a fan comprising a hub and a plurality of blades extending radially outward from the hub and spaced circumferentially around the hub. The plurality of blades comprises a reference blade, a first blade, and a second blade. The reference blade is disposed behind the first blade in a circumferential direction around the hub. The second blade is disposed behind the reference blade in a circumferential direction. The first blade is spaced circumferentially from the reference blade by a first distance. The second blade is spaced circumferentially from the reference blade by a second distance. The first distance is greater than the second distance.

[0003] In another independent aspect, the present disclosure provides a fan comprising a hub and a plurality of blades, the hub having an air induction cone and a blade connection portion, the plurality of blades extending radially outward from the blade connection portion and spaced circumferentially around the hub. The blade connection portion tapers radially inward and meets the air induction cone in a tangential direction.

[0004] In another independent aspect, the present disclosure provides a handheld blower, the handheld blower comprising an air duct and a fan, the air duct extending along an axis, the air duct comprising an air inlet and an air outlet opposite to the air inlet, the fan being disposed in the air duct between the air inlet and the air outlet. The fan rotates about the axis. The fan comprises a fan hub and a plurality of fan blades, the fan hub extending from an upstream end to a downstream end, the fan hub defining an outer surface with a radius that increases continuously from the upstream end to the downstream end, the plurality of fan blades extending radially outward from the outer surface between the upstream end and the downstream end. The plurality of fan blades are divided into a plurality of pairs of blades. The plurality of pairs of blades are evenly spaced from each other in a circumferential direction around the fan hub.

[0005] Other features and aspects of the present disclosure will become apparent by consideration of the following detailed description and accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Figure 1 is a perspective view of a handheld blower according to an embodiment disclosed herein.

[0007] Figure 2 yes Figure 1 A cross-sectional elevation view of a portion of a handheld blower.

[0008] Figure 3 is a perspective view of a fan according to an embodiment disclosed herein.

[0009] Figure 4 yes Figure 3A front elevation view of a portion of a fan.

[0010] Figure 5 yes Figure 3 A cross-sectional front elevation view of a fan.

[0011] Figure 6 is a perspective view of a fan according to an embodiment disclosed herein.

[0012] Figure 7 yes Figure 6 Exploded perspective view of the fan.

[0013] Figure 8 yes Figure 6 Front elevation view of a fan.

[0014] Fig. 9 yes Figure 8 A cross-sectional side elevation view of the fan taken along line 9-9.

[0015] Fig.10 yes Figure 8 A cross-sectional side elevation view of the fan taken along line 10-10.

[0016] Before explaining any embodiments of the present disclosure in detail, it should be understood that the present disclosure is not limited in its application to the construction details and component arrangements set forth in the following description or shown in the following figures. The present disclosure can have other embodiments and can be practiced or performed in various ways. In addition, it should be understood that the words and terms used herein are for descriptive purposes and should not be considered restrictive. DETAILED DESCRIPTION

[0017] Figure 1 and Figure 2 Generally, a handheld blower 10 is shown including a housing 14. The housing 14 includes a handle 18 and a battery receiving area 22 for receiving one or more battery packs 26. A blow tube 30 is connected to the housing 14 and includes an outlet 34. Figure 2, the housing 14 defines an air duct 38 extending between an air duct inlet 46 and an air duct outlet 50 along an air duct axis 42, and the air duct outlet is located opposite and downstream of the air duct inlet 46. The blowpipe 30 is located near the air duct outlet 50 to create an air flow path 54 extending between the air duct inlet 46 and the outlet 34. The grille 58 is located near the air duct inlet 46. The motor assembly 62 is located in the air duct 38 and includes a motor 66 and a fan 74. The motor 66 and the fan 74 are located in the air duct 38 for rotating around an axis of rotation 78. In the illustrated embodiment, the axis of rotation 78 is coaxial with the air duct axis 42. In the illustrated embodiment, the motor assembly 62 is assembled so that the fan 74 is located upstream of the motor 66. However, in other embodiments, the motor assembly 62 can be assembled into other configurations.

[0018] Figures 3 to 5 Shows, for example, Figure 1 to Figure 2 The fan 100 is used in conjunction with the handheld blower 10 of the present invention. The fan 100 includes a fan hub 104 defining an outer surface 108. A plurality of blades 112 extend radially outward from the outer surface 108 of the fan hub 104. The fan hub 104 may include a body 116 and a hub cap or air guide cone (not shown, but discussed below in conjunction with other embodiments). In some embodiments, the hub cap is formed as a separate component and is removed from the body 116. However, in other embodiments, the hub cap may be integrally formed with the body 116. The fan 100 may include a passage 120 extending through the fan hub 104, the passage defining a central rotation axis 124 or rotation axis 124 of the fan 100. The fan 100 may be supported in a handheld blower or other air moving machine to rotate about the central rotation axis 124 along a rotation direction 128.

[0019] Each blade 112 extends between a blade base 132 and a blade tip 136, wherein the blade tip 136 is located at a cantilever end 140 of the blade 112. The blade 112 defines a leading edge 144 and a trailing edge 148 extending between the blade base 132 and the blade tip 136. In the illustrated embodiment, the leading edge 144 can be generally straight, while the trailing edge 148 can be curved. However, in other embodiments, fan blades of other shapes can be used. In the illustrated embodiment, each of the plurality of blades 112 is identical to the other blades, such that the pitch, shape, width, and length of the blades are the same.

[0020] Specific reference Figure 4 and Figure 5, the plurality of blades 112 may be unevenly spaced about the fan hub 104. For ease of discussion, one of the plurality of blades 112 has been identified as the reference blade 152. Although one particular blade has been identified and the relationships between the blades have been discussed with respect to the reference blade 152, the relationships apply equally regardless of which blade 112 is selected as the reference blade 152, unless otherwise noted.

[0021] like Figure 4 As shown, the reference blade 152 has a reference tip 156 and a reference leading edge 160. The reference tip 156 and the reference leading edge 160 meet at a reference corner 164. A first adjacent blade 168 (or first blade 168) is sequentially located next to the reference blade 152 in a direction opposite to the circumferential direction 170 (or first direction). In other words, the reference blade 152 is arranged behind the first blade 168 along the circumferential direction 170. In the illustrated embodiment, the circumferential direction 170 is the same as the rotation direction 128 of the fan 100, however, in other embodiments, the circumferential direction 170 may be opposite to the rotation direction 128. A second adjacent blade 172 (or second blade 172) is sequentially located next to the reference blade 152 in the circumferential direction 170 (or second direction). The first adjacent blade 168 includes a first tip 180 and a first leading edge 184, which intersect at a first corner 188. The second adjacent blade 172 includes a second tip 192 and a second leading edge 196 that intersect at a second corner 200 .

[0022] The reference blade 152 is spaced a first distance from the first blade 168 in the circumferential direction, and the reference blade 152 is spaced a second distance from the second blade 172 in the circumferential direction. Specifically, the first distance can be measured as a first angle α1 measured between the first corner 188 and the reference corner 164 around the axis of rotation 124. The second distance can be similarly measured as a second angle α2 measured between the reference corner 164 and the second corner 200 around the axis of rotation 124. The first angle α1 is different from the second angle α2. In the case of the exemplary reference blade 152, the first angle α1 is greater than the second angle α2. If another blade is selected as the reference blade, this relationship may be reversed. Although the first distance and the second distance can be described by angles, a linear distance or an arc distance between the blades can also be used. The relationship between the spacings will remain the same, so that the first length will be greater than the second length.

[0023] In the illustrated embodiment, the plurality of blades 112 includes twelve blades 112 that are divided into a plurality of pairs of blades 204 that are evenly spaced around the fan hub 104. Thus, each blade 112 has a corresponding blade 112 at a radially opposite position. In addition, the third adjacent blade 208 (or the third blade 208) is sequentially located next to the first adjacent blade 168 in the first direction. Or in other words, the third blade 208 is located before the first blade 168 in the circumferential direction 170. The fourth adjacent blade 212 is sequentially located next to the second adjacent blade 172 in the second direction. In other words, the fourth blade 212 is located after the second blade 172 in the circumferential direction 170. The third adjacent blade 208 includes a third leading edge 216 and a third end 220 that intersect at a third corner 224, and the fourth adjacent blade 212 includes a fourth leading edge 228 and a fourth end 232 that intersect at a fourth corner 236. The third blade 208 is circumferentially spaced a third distance from the reference blade 152. The third distance can be measured as a third angle α3 measured about the rotation axis 124 between the third corner 224 and the reference corner 164. The fourth blade 212 is circumferentially spaced a fourth distance from the reference blade 152. The fourth distance can be expressed as a fourth angle α4 measured about the rotation axis 124 between the fourth corner 236 and the reference corner 164. The third angle α3 is equal to the fourth angle α4. Similarly, the linear distance can be used instead of the angle to obtain the same result, so that the third length will be equal to the fourth length.

[0024] The fan 100 is rotationally symmetric about the rotation axis 124. In other words, the spacing between each of the plurality of blades 112 alternates between a first distance (e.g., a first angle α1) and a second distance (e.g., a second angle α2) along the circumferential direction 170. Rotational symmetry means that the plurality of blades 112 are rotationally balanced about the fan hub 104.

[0025] Reference Figure 5 , although the distance is described as the angle measured between corresponding corners, the relationship between the leaves remains unchanged if similar points on each leaf are used. For example, Figure 5 The stagger angles (β1 to β4) measured between the center points on each blade are shown. The first angle β1 is still different from and greater than the second angle β2. The third angle β3 is still equal to the fourth angle β4.

[0026] In operation, the uneven spacing allows air to flow through the fan 100 at high speeds while reducing frequencies that are typically perceived as objectionable by users compared to fans with evenly spaced blades. For example, embodiments of the fan 100 may primarily produce an output frequency of approximately 1500 Hz. In contrast, a fan with evenly spaced blades may primarily produce an output frequency of approximately 3200 Hz.

[0027] Figures 6 to 10 Shows, for example, Figure 1 and Figure 2 Another embodiment of a fan 300 for use with the handheld blower 10 of the present invention is shown. The fan 300 includes a fan hub 304 and a plurality of blades 308 extending radially outward from the fan hub 304. The plurality of blades 308 are shown as being evenly spaced around the hub 304, however, in some embodiments, the plurality of blades 308 may be spaced apart as shown in FIG. Figures 3 to 5 The fan hub 304 includes a body 312 and a wind guide cone 316. Figure 7 As shown, the wind guide cone 316 can be removably coupled to the body 312. However, in some embodiments, the wind guide cone 316 can be formed integrally with the body 312. The fan 300 includes a channel 320 extending through the body 312. The channel 320 defines a central rotation axis 324 (or rotation axis 324). The channel 320 can receive a shaft or other support member to rotatably support the fan 300 in the handheld blower 10. Figure 6 In the illustrated embodiment, the forward direction may be generally upstream, while the rearward direction may be generally downstream. Although the terms "forward," "front," "upstream," "rearward," "rear," and "downstream" may be used to describe the fan, these directions do not necessarily correspond to the directions of the motor assembly, the handheld blower, or the environment. Directional language is used for descriptive purposes only and is not meant to limit the embodiments to a certain orientation.

[0028] Reference Figures 6 to 8 As described above, the fan hub 304 includes a body 312 and a wind guide cone 316. A plurality of blades 308 may extend from the body 312 and may be formed integrally with the body. In other embodiments, the plurality of blades 308 may be fixed to the body 312 in other ways. The body 312 may also be referred to herein as a blade connection portion 312. The body 312 may be radially tapered inward. The body 312 may include a circumferential surface 328. The circumferential surface 328 may be the radially outermost surface of the body 312. A plurality of blades 308 may extend from the circumferential surface 328. The body 312 may extend between a rear end 332 and a body connection end 336, which is configured to be coupled to the wind guide cone 316.

[0029] The wind guide cone 316 may extend between the truncated end 340 and the cone connection end 344. The cone connection end 344 may be coupled to the body connection end 336 of the body 312. The wind guide cone 316 may further include a cone surface 348. The cone surface 348 may be the radially outermost surface of the wind guide cone 316. The cone surface 348 may be curved relative to the central rotation axis 324.

[0030] Now go to Fig. 9 and Fig.10 , the circumferential surface 328 and the conical surface 348 may be combined to form a hub outer surface 352. The shape of the wind guide cone 316 and the body 312 may be such that the circumferential surface 328 and the conical surface 348 meet tangentially at the connection point 356. The hub outer surface 352 may be continuously tapered radially inwardly between the rear end 332 and the truncated end 340.

[0031] Specifically, Fig. 9 As shown, in a vertical section through the fan 300 parallel to the rotation axis 324, the hub outer surface 352 can form a curved profile 360. The curved profile 360 ​​may include a first point 364 located at the truncated end 340, a second point 368 located at the rear end 332, and an intermediate point 372 located between the first point 364 and the second point 368. In some embodiments, the intermediate point 372 and the connection point 356 between the tapered surface 348 and the circumferential surface 328 are located at the same position. However, the intermediate point 372 can be any point on the curved profile 360 ​​between the first point 364 and the second point 368. The first point 364 can be radially located at a first distance R1 relative to the rotation axis 324. The second point 368 can be located at a second distance R2 relative to the rotation axis 324, and the intermediate point 372 can be radially located at an intermediate distance R from the rotation axis 324. I Place.

[0032] like Fig. 9 As shown, a tangent line is taken at each point 364, 368, 372. The tangent line taken at the first point 364 forms a first angle 388 relative to the rotation axis 324. The tangent line taken at the second point 368 forms a second angle 392 relative to the rotation axis 324. Finally, the tangent line taken at the intermediate point 372 forms an intermediate angle 396 relative to the rotation axis 324. The hub 304 tapers inwardly so that the slope of the hub outer surface 352 is more intense at the truncated end 340 than at the rear end 332. In other words, the first angle 388 is greater than the second angle 392. In addition, the hub 304 is shaped so that the hub outer surface 352 is never parallel to the rotation axis 324. Finally, the hub 304 is shaped so that the angle of the tangent line to the curved profile 360 ​​continuously decreases between the truncated end 340 and the rear end 332. Thus, the first angle 388 is greater than the intermediate angle 396, and the intermediate angle is greater than the second angle 392.

[0033] In operation, the shape of the deflector cone 316 provides the fan hub 304 with an increased pull-off angle compared to a standard fan hub. Fig.10As shown, each blade 308 is connected to the fan hub 304 at an upstream connection point 400 and a downstream connection point 404. A first length L1 is measured between the upstream connection point 400 and the tip 408 of the blade 308. A second length L2 is measured between the downstream connection point 404 and the tip 408 of the blade 308. Due to the taper of the blade connection portion 312, the first length L1 is greater than the second length L2, which means that the available blade surface of the plurality of fan blades 308 is maximized, or at least greater than that of a standard fan, for contacting the operating medium (e.g., air). As a result, the fan 300 has a higher fan efficiency than a standard fan.

[0034] Although the present disclosure has been described in detail with reference to several preferred embodiments, various variations and modifications exist within the scope and spirit of one or more independent aspects of the disclosure as described.

Claims

1. A fan, comprising: Wheel hub; a plurality of blades, each blade of the plurality of blades comprising a blade base coupled to the hub, each blade extending radially outward from the hub to a cantilevered end, the plurality of blades being circumferentially spaced about the hub, the plurality of blades comprising a reference blade, a first blade, and a second blade; and in, The reference blade is arranged behind the first blade in a circumferential direction around the hub, and the second blade is arranged behind the reference blade in the circumferential direction, The first blade is spaced apart from the reference blade by a first distance in the circumferential direction, The second blade is spaced apart from the reference blade by a second distance in the circumferential direction, and The first distance is greater than the second distance.

2. The fan according to claim 1, wherein: The plurality of blades is twelve blades.

3. The fan according to claim 1, wherein: The hub includes an outer surface, and The plurality of vanes extend from the outer surface.

4. The fan according to claim 1, wherein: The plurality of blades are divided into a plurality of pairs of blades that are evenly spaced apart from each other in a circumferential direction around the hub.

5. The fan according to claim 1, wherein: The blades are identical.

6. The fan according to claim 1, wherein: The hub includes a passage for receiving a shaft, the passage defining a central rotational axis of the fan.

7. The fan according to claim 1, wherein: The fan is rotationally symmetrical.

8. The fan according to claim 1, wherein: Each of the plurality of blades has corresponding blades at radially opposite positions.

9. The fan according to claim 1, wherein: Any leaf among the plurality of leaves can be considered as the reference leaf.

10. The fan according to claim 9, wherein: The circumferential spacing between the blades alternates between the first distance and the second distance along the circumferential direction.

11. A fan, comprising: A hub, the hub comprising an air induction cone and a blade connecting portion, the blade connecting portion radially inwardly tapering and meeting the air induction cone in a tangential direction; as well as A plurality of blades, each of the plurality of blades includes a blade base coupled to the hub, each blade extending radially outward from the blade connection portion to a cantilever end, the plurality of fan blades being divided into a plurality of pairs of blades that are evenly spaced apart from each other circumferentially around the hub.

12. The fan according to claim 11, wherein The blade connection portion tapers radially inwardly along the entire axial length of the blade connection portion.

13. The fan according to claim 11, wherein The air inducing cone is removably coupled to the blade connecting portion.

14. The fan according to claim 11, wherein The plurality of blades and the blade connecting portion form a single integral part.

15. The fan according to claim 11, wherein The wind induction cone and the blade connecting portion form the outer surface of the hub, and The outer surface of the hub tapers inwardly along the entire axial length of the hub.

16. The fan according to claim 11, wherein Each blade of the plurality of blades has a radial length through the upstream connection point that is greater than a radial length through the downstream connection point.

17. The fan according to claim 11, wherein The air inducing cone has a truncated end.

18. The fan according to claim 11, wherein The blade connection portion includes a passage as defined herein for receiving a shaft, the passage defining a central rotational axis of the fan.

19. The fan according to claim 18, wherein: The blade connection portion tapers radially inwardly in an upstream direction along the central rotational axis.

20. A handheld blower comprising: An air duct extending along the axis, the air duct comprising an air inlet and an air outlet opposite to the air inlet; as well as A fan, the fan is arranged in the air duct between the air inlet and the air outlet, the fan is configured to rotate around the axis, and the fan comprises: a fan hub extending from an upstream end to a downstream end, the fan hub defining an outer surface having a radius that increases from the upstream end to the downstream end, and A plurality of fan blades extend radially outward from the outer surface between the upstream end and the downstream end, each of the plurality of blades including a blade base coupled to the hub, each of the plurality of blades extending to a cantilever end, the plurality of fan blades being divided into a plurality of pairs of blades that are evenly spaced apart from one another in a circumferential direction around the fan hub.

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