JP2017115769A - Blade for blower, and blower - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce noise of a blower, the blower including a blade for a blower having a blade body and a standing blade erected on an outer peripheral edge of the blade body.SOLUTION: A blade 1 for a blower includes a blade body 2 and a standing blade 3 erected on an outer peripheral edge of the blade body 2. A height of the standing blade 3 is substantially constant in the rear of an intermediate point M. A height of the standing blade 3 is gradually reduced forward from the intermediate point M. The standing blade 3 is inclined in a radiation direction with respect to upright. An intersection angle δ between the standing blade 3 and the blade body 2 falls within a range of 90.1-91°.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a blower blade used in an axial flow blower, and more particularly to a blower blade provided with standing blades along the outer peripheral edge of a blade body. The present invention also relates to a blower provided with the fan blades and a cooling tower provided with the blower.

  As a cooling tower blower or the like, an axial flow blower in which a shroud surrounds a blade attached to a hub is widely used. In this axial flow type blower, fluid (in many cases, air) flows in the axial direction of the hub by rotating the blades. At this time, a pressure difference is generated on both sides of the blade, and the air flows backward through the gap between the outer peripheral edge of the blade and the inner surface of the shroud. As the air flows backward, a vortex is generated at the tip of the blade and noise is generated.

  In order to reduce this noise, Patent Documents 1 and 2 describe providing standing blades that stand along the outer peripheral edge of the blade body toward the downstream side in the blowing direction. In Patent Document 1, the blade body is referred to as a blade, and the upright blade is referred to as an auxiliary blade. In Patent Document 2, the upright blade is referred to as a blade end plate.

JP 2000-314394 A JP 2013-96307 A

  When the blade of the blower is rotated, a centrifugal force that is inclined in the radial direction by the centrifugal force acts on the standing blade. In order to resist this centrifugal force, it is conceivable that the upright blade is inclined (inwardly tilted) toward the blade body side, and at the same time, the thickness near the intersection of the blade body and the upright blade is increased to reinforce. .

  However, in the case where the standing blade has an inward shape, the angle between the standing blade and the blade body is an acute angle even if the shape of the reinforcing part is curved. Since the pressure fluctuation at the time of leaving tends to be abrupt, there is a risk that the air current is disturbed, and the noise reduction effect by the standing wing provided along the outer peripheral edge of the wing body may be impaired.

  An object of this invention is to suppress the falling of a standing blade, fully exhibiting the noise suppression effect of the fan blade which has a standing blade.

  The blade for a blower of the present invention is a blade of a blower having a hub, a blade attached to the hub, and an annular shroud surrounding the outer periphery of the blade, and the proximal end side of the blade is attached to the hub. In a fan blade having a blade body and a standing blade standing on the downstream side in the blowing direction from the outer periphery of the blade body, the rising blade is inclined more radially than the upright blade from the blade body. It is characterized by.

  In one aspect of the present invention, the intersection corner between the blade body and the upright blade is a curved surface that is concavely curved.

  In one aspect of the present invention, the intersection corner between the blade body and the upright blade is a curved surface that is concavely curved, and the radius of curvature of the curved surface is smaller toward the trailing edge side of the fan blade.

  In one aspect of the present invention, the inclination angle (intersection angle between the standing blade and the blade body) is 90.1 ° to 91 °.

  In one aspect of the present invention, the height of the upright blade is greater on the rear side than on the front side with respect to the intermediate portion M in the outer peripheral edge direction.

  The blower of the present invention has a hub, the fan blades of the present invention attached to the hub, and a shroud surrounding the fan blades.

  In the blower of the present invention, the radius of curvature of the outer peripheral edge of the fan blade is smaller than the radius of curvature of the inner surface of the shroud.

  The cooling tower of the present invention has the blower as the blower.

  The wing for a blower of the present invention is characterized in that the upright wing is inclined in the radial direction from the wing main body in the radial direction (outside down). Due to this shape, when the blade is rotated, the entire blade is bent by centrifugal force, so that the ratio between the blade body length L (rotation radial direction length) and the blade body width B (rotation circumferential direction length). (Aspect ratio L / B) apparently increases, suppressing the generation of airflow turbulence (airflow vortex), which is one of the causes of noise generated behind the blade rotation, that is, efficiency as a fan blade I can do it.

  In addition, when the standing wing is turned over, the angle with the wing body becomes an obtuse angle, and the vortex between the standing wing and the wing body is broken when turning at the front edge of the wing body by rotation. The effect of reducing the generation can be expected.

  Furthermore, by making the intersecting corner of the standing wing and the wing body into a curved surface that is concavely curved, it is necessary to resist the force related to the lower part of the standing wing that supports the upside-down standing wing, that is, the portion that engages with the wing body. The radius of curvature of the reinforcement build-up surface is larger than when the reinforcement equivalent to that of the upright standing wing is performed. That is, since the standing blade and the blade body are connected with a more gently curved surface, the effect of reducing the above-described generation of vortices can be further expected.

  In addition, by reducing the radius of curvature of the intersection corner between the blade body and the upright blade toward the rear side, specifically, the curvature of the curved surface from approximately the center of the blade body width B to the trailing edge of the blade. Since the radius is small, generation of vortices due to the airflow discharged from the blade trailing edge can be suppressed, and noise is expected to be small.

  If the radius of curvature of the curved surface at the intersection corner between the blade body and the upright blade decreases rapidly toward the trailing edge of the blade, that is, if the amount of change in the radius of curvature is large, the generation of airflow vortices may increase. In order to reduce the amount of change in the curvature radius, it is preferable to make the curvature radius of the surface itself as small as possible.

  However, when the radius of curvature is reduced, the amount of build-up is naturally reduced, so that the reinforcement at the lower part of the standing wing becomes insufficient. On the other hand, the blower blade of the present invention has the same amount of change in the radius of curvature and the same reinforcing effect (meat) as compared with the case of the upright blade standing upright with respect to the blade body by turning the upright blade outward. In the case of trying to obtain the fill amount), the build-up amount increases, so that in addition to suppressing the generation of airflow vortices, it is possible to expect both the improvement effect of the upright blades at the same time.

It is a perspective view from the downstream of the blade for blowers concerning an embodiment. (A) is the elements on larger scale of FIG. 1, (b) is the perspective view which described the explanatory line in (a). (A) is a top view of the outer peripheral edge side of the fan blade according to the embodiment, and (b) is an enlarged view of a part (rear edge side) of (a). It is a side view (IV arrow line view of FIG. 2) of the standing wing | blade of the wing | blade for air blowers. It is sectional drawing which follows the VV line of FIG. (A) is a plan view of a blade blower, (b) is a sectional view taken along the _B 1 -B _1-wire and _B 2 -B _2-wire (a). It is the top view which looked at the air blower from the upstream.

  Hereinafter, embodiments will be described with reference to the drawings.

  As shown in FIG. 1, the blower blade 1 includes a blade body 2 and upright blades 3 erected on the downstream side from the outer peripheral edge 2 g (FIG. 3) side of the blade body 2. The boss 4 on the base end side of the wing body 2 is attached to the hub 11 (FIG. 7) of the blower 10. A plurality of blower blades 1 are attached to the hub 11, and a short cylindrical shroud 12 surrounds the outer periphery thereof.

As shown in FIG. 6B, the blade main body 2 has a cross section in the front-rear direction of rotation that is convexly curved toward the upstream side in the air blowing direction like the B ₁ -B ₁ and B ₂ -B ₂ cross sections.

  The leading edge 2a of the blade body 2 is curved so as to be concave toward the front in the rotational direction of the fan blade 1.

  The trailing edge 2b of the wing body 2 is curved so as to be convex rearward in the rotational direction except for the outer peripheral edge side, and becomes a main trailing edge 2c. The outer peripheral edge side of the main trailing edge 2c is in the rotational direction. The blade end side trailing edge 2d is curved concavely toward the rear. The main trailing edge 2c and the blade tip side trailing edge 2d are continuous at the point Q.

  That is, in the state of FIG. 6A in which the fan blade 1 is viewed in plan, the main trailing edge 2c is in the rotational direction with respect to the straight line UQ connecting the point U on the most hub side of the trailing edge of the blade body 2 and the point Q. Projected back in a bow shape. The blade end side rear edge 2d recedes in an arc shape forward in the rotational direction from a straight line QE connecting the point E on the outermost peripheral edge side of the rear edge of the blade body 2 and the point Q. 2B, the point P is the point where the extended line of the tangent m of the main trailing edge 2d at the point Q intersects the outer peripheral edge 2g of the blade body 2.

  The front edge 2a of the wing body 2 recedes in an arcuate shape behind the straight line TF connecting the point T on the outermost hub side and the front end point F on the outermost peripheral edge side.

  The main trailing edge 2c in the fan blade of the present invention may be a straight line (not shown). And the front edge 2a in that case may be a straight line, or may be curving so that it may become concave toward the rotation direction front of the fan blade 1 (not shown). Preferably, the main trailing edge 2c is curved, for example, as shown in FIG. 6, so as to protrude rearward in the rotational direction, from the viewpoint of suppressing the vortex generation of the airflow.

  The upright wing 3 is slightly inclined in the radial direction from the wing body 2 rather than upright. As shown in FIG. 5, the crossing angle δ between the vicinity of the outer peripheral edge of the blade body 2 and the upright blade 3 is preferably 90.1 ° to 91 °, particularly 90.3 ° to 90.7 °.

  The upright blade 3 is preferable because it can be expected to start rising from a point 3f slightly separated from the front end point F of the blade body 2 to reduce the resistance value caused by the rotation of the blade and to suppress the turbulence of the airflow. . The rising height of the standing wing gradually increases toward the rear. The height h (FIG. 2 (b)) of the upright blade 3 is substantially the highest at the front-rear direction intermediate point M of the outer peripheral edge of the blower blade 1, and the height of the upright blade 3 is substantially constant behind the intermediate point M. is there. The height h of the upright blade 3 at the intermediate point M is more than 4% of the total length L (see FIG. 6) of the blade 1 from the hub center (rotation center) C, and the upper limit is preferably less than 9% of L. , More preferably less than 5-8%, particularly preferably less than 6-8%.

  The separation distance between the front end point 3f (FIG. 3) of the upright blade 3 and the front end point F of the blade 1 is 8% or less of the total length (distance between points EF) of the outer peripheral edge of the fan blade 1, particularly 3 to 3. 6% is preferred. However, the front end of the upright wing 3 may be a point F.

  The inner peripheral surface 5a at the crossing corner of the upright blade 3 and the blade body 2 is concavely curved as shown in FIG. The curvature radius R of the inner peripheral surface 5a is larger than the curvature radius of the outer peripheral surface 5b. Such a configuration is preferable because the strength of the blade tip is improved. Further, in this embodiment, the radius of curvature R of the inner peripheral surface 5a is configured to become smaller toward the rear side of the blade body 2. Therefore, the wall thickness t of the intersection corner is smaller toward the rear side of the blade body 2. In addition, it is preferable that this curvature radius R is 20 mm or more in the vicinity of the intermediate point M, for example, 20-40 mm, especially 25-35 mm. The curvature radius is substantially the same on the leading edge side from the intermediate point M, but the curvature radius gradually decreases toward the tip in the vicinity of the tip. Note that the degree of temporary decrease in the radius of curvature is gentle compared to that on the trailing edge side. On the trailing edge side from the intermediate point M, the radius of curvature gradually becomes smaller. In the vicinity of the point E at the last edge, the radius of curvature R is preferably 10 mm or less, for example, about 1 to 10 mm, particularly about 5 to 8 mm.

  The upright blade 3 extends rearward from the intersection P between the tangent m at the point Q and the outer peripheral edge 2 g of the blade body 2. In this embodiment, the upright blade 3 reaches the intersection E between the outer peripheral edge 2g of the blade body 2 and the trailing edge 2b (wing tip side trailing edge 2d). Such a configuration is preferable because it can be expected to reinforce the rearward extending portion of the upright blade and suppress the turbulence of the airflow.

  The crossing angle θ between the upper side 3a and the rear side 3b at the rearmost part of the upright blade 3 is substantially a right angle (specifically, θ = 85 ° to 95 °, particularly 88 ° to 92 °).

  In the following description, the area of the side surface of the upright wing 3 on the rear side of the point P may be referred to as an end area S, and the length of the upright wing 3 on the rear side of the point P may be referred to as an allowance length D. . Further, the rear side of the blade body 2 from the tangent line m, that is, the blade end side rear edge 2d side, may be referred to as a protruding portion W. The blade body 2 including the overhang portion W has a thickness increasing toward the outer peripheral edge of the blade body at the blade tip. Specifically, the projecting portion extends from the line in the front-rear direction of the blade rotation passing through the connection point Q (a line segment parallel to the line segment B1-B1 or B2-B2 in FIG. 6B) toward the outer periphery of the blade. The thickness of the wing body 2 including W is gradually increased.

  In the present invention, the tangent m and the wing tip side trailing edge 2d may coincide. That is, the area of the overhanging portion W may be 0 (zero). In this case, the upright blade 3 extends rearward from the point P.

  In the blower 10 having the blower blade 1, the hub 11, and the shroud 12, the blower blade 1 is rotationally driven in a clockwise direction in FIG. 7 by a motor (not shown), and air is blown. The pitch angle α of the blade 1 (intersection angle between the straight line EF and the horizontal plane when the rotation axis is vertical) is preferably about 5 to 30 °.

  The effects of the fan blade 1 and the fan 10 are as follows. In the blower 10, the rising blade 3 is provided on the blower blade 1, and noise during blowing is small as compared with the case where the rising blade is not provided. In particular, in this embodiment, the height h of the upright blade 3 is appropriate, and the upright blade 3 extends long rearward, so that the noise reduction effect is good. Further, the front end point 3f of the upright blade 3 is retracted by a predetermined distance from the point F, and the effect of suppressing the vortex in the vicinity of the front edge of the outer peripheral edge of the blade body 2 is obtained, which also reduces the noise.

  In the present invention, since the upright blade 3 is inclined in the radial direction, the blade main body length L (rotational radial length) and the blade main body width B (rotational circumferential length) are obtained by bending the entire blade by centrifugal force. Ratio (aspect ratio L / B) is apparently increased, suppressing the generation of airflow turbulence (airflow vortex), which is one of the causes of noise generated behind the blade rotation, that is, efficiency as a fan blade I can do it.

  In this embodiment, the thickness of the blade body 2 is increased in the vicinity of the point E. Specifically, the projecting portion extends from the line in the front-rear direction of the blade rotation passing through the connection point Q (a line segment parallel to the line segment B1-B1 or B2-B2 in FIG. 6B) toward the outer periphery of the blade. Since the thickness of the blade main body 2 including W is gradually increased, the strength and rigidity of the fan blade 1 near the point E is high, but the weight increase due to this is very small. In this embodiment, the radius of curvature R (FIG. 5) of the inner circumferential surface of the blade body 2 and the upright blade 3 is made smaller toward the trailing edge 2b side. Thereby, the effect which suppresses generation | occurrence | production of the vortex in the rear part side of the standing blade 3 is acquired.

  As shown in FIG. 6, in this embodiment, the outer peripheral edge 2 g of the wing body 2 is curved so as to protrude outward in the diameter direction of the rotation of the wing body 2. The radius of curvature of the outer peripheral edge 2g is smaller than the radius of curvature of the inner peripheral surface of the shroud 12.

  As described above, the trailing edge of the upright blade 3 having the large height h of the upright blade 3 is deformed so as to fall outward (radially) by centrifugal force when the fan blade 1 rotates. Combined with the effect of suppressing the tilt of the upright blade 3 according to this embodiment by setting the radius of curvature of the outer peripheral edge 2g of the blade body 2 smaller than the radius of curvature of the inner peripheral surface of the shroud 12. Further, the effect of preventing contact between the upright blade 3 and the inner peripheral surface of the shroud 12 is improved.

  There is no restriction | limiting in the use of the fan blade | wing of this invention, The fan blade | wing for cooling towers, a CPU cooling fan, the radiator cooling fin of a motor vehicle, a ventilation fan, a fan (type with a casing) etc. are mentioned. Among these, cooling tower fan blades that have a remarkable noise reduction effect are preferred.

  Although there is no restriction | limiting in the raw material and shaping | molding method of a wing | blade for air blowers, From the request | requirement of large sized, high intensity | strength, lightweight, etc., the wing | blade for air blowers is preferable from FRP.

  The method for manufacturing the blades for the blower is optional, but since the fan for the cooler tower is generally large, a fiber reinforced thermosetting resin composition containing CF (carbon fiber) or GF (glass fiber). Sheet molding (SMC) in which a sheet is placed in a mold and embossed is preferable.

  In the SMC manufacturing method, it is preferable to manufacture by installing a molding die so that the end portion of the upright blade 3 is directed downward so that the molten resin composition flows to the end portion of the upright blade 3.

  At the time of SMC molding, the composition ratio and installation method of the fiber reinforced thermosetting resin composition sheet are appropriately selected, and in the thermosetting resin composition flowing into the end of the upright blade 3, a fibrous substance such as CF or GF May be adjusted, the fiber amount at the end of the upright blade 3 may be adjusted, and the strength and weight may be adjusted.

  Preferably, the fibrous substance content in the thermosetting resin composition in the upright blade 3 is less than that of the blade body 2 and relatively reduces the weight (ie, suppresses the increase in the weight of the blade tip). It is preferable. This is because, as the weight of the blade tip is lighter during blade rotation, the blade body can be prevented from being deformed (deflection) by rotation, the clearance between the shroud 12 and the upright blade 3 can be easily adjusted, and can be rotated safely. This is because it can.

  Note that, when the blower blade 1 is removed from the molding die, the upright blade 3 is inclined in the radial direction with respect to the blade body 2, so that the removal is easy.

DESCRIPTION OF SYMBOLS 1 Fan blade 2 Blade body 2c Main trailing edge 2d Blade tip side trailing edge 3 Standing blade 10 Blower 11 Hub 12 Shroud

Claims (8)

The wing of a blower having a hub, a wing attached to the hub, and an annular shroud surrounding the outer periphery of the wing,
The blade is a blade for a blower having a blade body whose base end side is attached to the hub, and a standing blade erected on the downstream side in the blowing direction from the outer periphery of the blade body.
The fan blades characterized in that the upright blades are inclined in a radial direction from the blade main body in an upright direction.   2. The fan blade according to claim 1, wherein an intersection corner portion between the blade body and the upright blade is a curved surface that is concavely curved.   In Claim 2, the intersection corner of the blade body and the upright blade is a curved surface that is concavely curved, and the curvature radius of the curved surface is smaller toward the trailing edge side of the fan blade. Blower for blower.   4. The fan blade according to claim 1, wherein an angle of intersection between the upright blade and the blade body is 90.1 ° to 91 °.   5. The fan blade according to claim 1, wherein a height of the upright blade is greater on the rear side than the front side of the intermediate portion M in the outer peripheral edge direction.   A blower comprising: a hub; the fan blade according to any one of claims 1 to 5 attached to the hub; and a shroud surrounding the fan blade.   The blower according to claim 6, wherein a radius of curvature of an outer peripheral edge of the blade for a blower is smaller than a radius of curvature of an inner peripheral surface of the shroud.   A cooling tower having the blower according to claim 6.

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