JP2009144579A - Fan and engine blower - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an engine blower capable of increasing a blade height while securing rigidity. <P>SOLUTION: Since both ends of each blade 32 are coupled by a shroud 33 and hub 31, sufficient rigidity which is equivalent to that of a close-type fan can be secured. In addition, since the shroud 33 is notched so that a radially outer end side of a wind catching surface 32A of the blade 32 is at least exposed, a blade height T can be increased by a thickness S of the shroud 33. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a fan and an engine blower.

  2. Description of the Related Art Conventionally, a fan used in an engine blower is known that has a hub formed in a disk shape and driven to rotate by the engine, and a plurality of blades erected radially on one side of the hub (for example, , See Patent Document 1). Since such a fan is an open type in which only one side of the blade is covered with the hub and the other side is opened, the height of the blade from the hub (blade height) can be increased. However, since only one end side of each blade is connected by a hub, there is a problem that when the size is increased, the rigidity of the entire fan tends to be insufficient.

Japanese Patent Laid-Open No. 2001-153096

In contrast to such an open type fan, a close type fan is also known.
FIG. 7 is a perspective view showing a conventional closed type fan 300.
In such a fan 300, since both ends of each blade 32 are connected by the hub 31 and the shroud 33, the rigidity can be improved, and it is possible to cope with an increase in size. However, since the other end side of each blade 32 is connected by the shroud 33, there is a problem that the blade height T is reduced by the thickness S of the shroud 33.

  An object of the present invention is to provide a fan and an engine blower that can increase the blade height while ensuring rigidity.

  A fan according to a first aspect of the present invention includes a hub formed in a disk shape, a plurality of blades erected at predetermined intervals along a circumferential direction on one side of the hub, the hub and the blade. And a shroud provided in an annular shape so as to sandwich the shroud, wherein the shroud is cut out so as to expose at least a radially outer end side of the wind-scraping surface of the blade.

  A fan according to a second aspect of the present invention includes the fan according to the first aspect, a volute case that accommodates the fan, and an engine that rotationally drives the fan.

  An engine blower according to a third aspect of the present invention is the engine blower according to the second aspect, wherein the volute case is formed with an annular funnel portion that forms an air intake, and the funnel portion, The fan shroud faces the shroud.

In the above, according to the first aspect of the present invention, since both ends of each blade are connected by the shroud and the hub, sufficient rigidity can be ensured.
Furthermore, since the shroud is cut out so as to expose at least the radially outer end side of the blade wind-up surface, the blade height can be increased by the thickness of the shroud.

  According to the invention of claim 2, since the same fan as described above is provided, the same effect as described above can be obtained.

Here, when the funnel part is integrally formed with the volute case, a groove is formed on the surface of the funnel part facing the fan along the edge surrounding the air intake. In the open type fan, there is a problem that noise is generated by the air from the air intake opening entering the groove and becoming a vortex.
In this regard, according to the invention of claim 3, since the shroud and the funnel portion are provided so as to face each other, when the fan rotates, the air taken into the central portion of the fan from the air intake port is It is sent to the outside in the radial direction of the fan through the pressure feed passage formed by the hub and the blade. Accordingly, since air from the air intake is hardly sent to the groove of the funnel portion, it is possible to suppress the generation of a vortex in the groove and to reduce noise due to the vortex.

[First Embodiment]
Hereinafter, a first embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a side sectional view showing an engine blower 1 according to the present embodiment.
The engine blower 1 is a backpack type, and has an L-shaped frame 2 having a horizontal base portion 21 and a vertical backrest portion 22 and a synthetic resin volute case 41 for accommodating a centrifugal fan 3. The centrifugal blower 4 supported on the frame 2, the engine 5 attached to the volute case 41 to rotationally drive the fan 3, and the elbow (not shown) of the volute case 41 attached to the pump 3 And a wind pipe (not shown) that blows out.

  Among these, the volute case 41 of the centrifugal blower 4 is integrally formed with an annular funnel portion 43 that forms an air intake 42. A plurality of rectifying fins 44 for rectifying the air sucked into the air intake 42 are provided on the surface of the funnel portion 43 (the surface not facing the fan 3). On the other hand, an annular groove 45 for weight reduction is formed along the edge surrounding the air inlet 42 on the back surface of the funnel portion 43 (the surface on the side facing the fan 3). In such a volute case 41, the fan 3 that is rotationally driven by the engine 5 is accommodated.

FIG. 2 is a perspective view showing the fan 3, and FIG. 3 is a plan view showing the fan 3.
The fan 3 is formed in a disc shape and fixed to the output shaft of the engine 5, a plurality of blades 32 erected at predetermined intervals along the circumferential direction on one side of the hub 31, and the hub 31. An annular and plate-like shroud 33 provided so as to sandwich the blade 32 is provided, and a closed type in which both sides of the blade 32 are covered with the hub 31 and the shroud 33 is provided. In the fan 3 of this embodiment, since both ends of each blade 32 are connected by the hub 31 and the shroud 33, sufficient rigidity comparable to that of the closed type fan can be obtained.

  By the way, in the case of an open type fan, there exists a problem that noise will generate | occur | produce when the air which passed the funnel part 43 enters into the groove | channel 45 (refer FIG. 1) formed in the back surface, and becomes a vortex | eddy_current. In this regard, in the fan 3 of the present embodiment, the shroud 33 is provided so as to face the groove 45 (see FIG. 1), and the pressure feed passage 34 is formed from the space surrounded by the shroud 33, the hub 31 and the blade 32. Thus, when the fan 3 rotates, the air taken into the central portion of the fan 3 from the air intake 42 is sent to the outside in the radial direction of the fan 3 through the pressure feed passage 34. For this reason, in the present embodiment, the compressed air is not sent to the groove 45 of the funnel portion 43, the generation of the vortex in the groove 45 can be suppressed, and the noise due to the vortex can be reduced.

  Further, in the open type fan, it is possible to suppress the generation of vortex by eliminating the groove 45 and forming the portion as a solid portion or a hollow portion. Since it is not necessary to form, the resin molding of the funnel part 43 becomes easy.

  By the way, in such a fan 3, it is easy to enlarge wind force, so that the braid | blade height in the pumping path 34 exit (radial direction outer end side of the pumping path 34) is large. In this regard, in the fan 3 of the present embodiment, a notch 35 is formed on the radially outer end side of the shroud 33 so as to completely expose the radially outer end side of the blade 32 of the blade 32 (see FIG. 3). Thereby, in this embodiment, compared with the conventional closed type fan 300, the blade height T at the outlet of the pressure feed passage 34 can be increased by the thickness S of the shroud 33, and the wind force can be increased.

  In addition, in this embodiment, compared with the conventional open type fan, the friction with the shroud 33 and the flow path resistance of the pressure-feed passage (the passage surrounded by the blades 32 in the open type fan 300) 34 are increased. However, by increasing the blade height T at the outlet of the pressure feed passage 34, it is possible to obtain wind power similar to that of an open type fan.

  FIG. 4 is a diagram showing measurement results of wind power of the conventional closed type fan 300 (without notches), the fan 3 of the present embodiment (with notches), and the conventional open type fan (open). These fans 3 and 300 are formed to have the same thickness from the hub 31 to the shroud 33 (the open type fan is from the hub 31 to the tip of the blade 32).

  As shown in FIG. 4, it can be confirmed that the fan 3 of this embodiment has larger wind power than the conventional closed type fan 300 in which the notch 35 is not formed. Moreover, it can be confirmed that the same (slightly large) wind power can be obtained even when compared with the open type fan.

[Second Embodiment]
FIG. 5 is a perspective view showing the fan 3A according to the present embodiment, and FIG. 6 is a plan view showing the fan 3A.
In the first embodiment, the shroud 33 is notched so that a part of the radially outer end side exposes the radially outer end side of the wind-scraping surface 32 </ b> A of the blade 32. 33 is formed in an annular shape by cutting out all the radially outer end sides. The pressure feed passage 34 is formed including a space V sandwiched between the radially outer ends of the blades 32.

  Even in the engine blower provided with such a fan 3A, the pressure feed passage 34 is formed including the shroud 33 provided so as to face the groove 45, so that the air taken into the center of the fan 3 is pumped. It is sent to the outside in the radial direction of the fan 3 through the passage 34. Therefore, the compressed air is not sent to the groove 45 of the funnel portion 43, and the generation of vortex in the groove 45 can be suppressed, and noise caused by the vortex can be reduced.

Further, since the radially outer end side of the wind-scraping surface 32A of the blade 32 is exposed, the blade height T at the outlet of the pressure passage 34 can be increased by the thickness S of the shroud 33, and sufficient wind power can be obtained. it can.
In addition, since both ends of each blade 32 are connected by the hub 31 and the shroud 33, sufficient rigidity can be secured.

[Modification of Embodiment]
It should be noted that the present invention is not limited to the above-described embodiments, and modifications, improvements, and the like within the scope that can achieve the object of the present invention are included in the present invention.
For example, the shape of the shroud 33 is not limited to that of the first and second embodiments, and the shroud 33 may be formed in any shape as long as the radially outer end side of the wind-scraping surface 32A of the blade 32 can be exposed. It may be.
In the first and second embodiments, the rectifying fins 44 are provided in the funnel portion 43, but the rectifying fins 44 may not be provided in the funnel portion 43.

  The present invention can be used for a fan and an engine blower including the fan.

1 is a side sectional view showing an engine blower according to a first embodiment of the present invention. The perspective view which shows a fan. The top view which shows a fan. The figure for confirming the effect of this invention. The perspective view which shows the fan which concerns on 2nd Embodiment of this invention. The top view which shows a fan. The perspective view which shows the conventional closed type fan.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Engine blower, 3, 3A ... Fan, 5 ... Engine, 31 ... Hub, 32 ... Blade, 32A ... Winding surface, 33 ... Shroud, 41 ... Volute case, 42 ... Air intake, 43 ... Funnel part.

Claims (3)

A hub formed in a disk shape;
On one side of the hub, a plurality of blades standing at predetermined intervals along the circumferential direction;
The hub and a shroud provided in an annular shape so as to sandwich the blade,
The fan is characterized in that the shroud is cut out so as to expose at least a radially outer end side of the wind-scraping surface of the blade. A fan according to claim 1;
A volute case for housing the fan;
An engine blower comprising: an engine that rotationally drives the fan The engine blower according to claim 2,
The volute case is formed with an annular funnel portion that forms an air intake,
The engine blower, wherein the funnel portion and the shroud of the fan face each other.

Images