JP2010242665A - Blower impeller - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the following problems: when a thin-walled portion is formed on the vacuum surface of each vane in order to reduce the weight of a blower impeller having thick-walled airfoil vanes, promotion of slight separation occurs, thereby causing a turbulent flow to deteriorate air volume performance and also to increase noise by the noise of the turbulent flow, and further, since the impeller has a thick-walled peripheral portion, productivity by resin molding is deteriorated. <P>SOLUTION: This blower impeller 2 includes a hub 3 rotatively driven by receiving torque from the outside, and a plurality of vanes 4 radially extending around the hub 3. The portion of each vane 4 on the side of a leading edge 5 has an airfoil shape, and the portion of each vane 4 on the side of a trailing edge 6 is formed to have a constant thick-walled shape. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a fan impeller capable of improving fan efficiency, improving air flow performance, reducing noise, and reducing weight.

The prior art is shown below. FIG. 8 is a perspective view of a conventional blower impeller. 9 to 11 are sectional views of blades of the blower impeller. The impeller 2 is provided with blades 4 in a hub portion 3 on a substantially cylindrical shape. Then, an aegri 1 in which the thickness of the blade 4 is reduced is provided in a predetermined range on the suction surface side of the blade 4. A motor shaft is fixed to the hub portion 3 of the impeller 2, and is placed in an appropriate casing, and is rotated in the direction of the arrow by the motor to produce a blowing action. At this time, air enters from the front edge 5 of the blade 2 and flows out from the rear edge 6. Therefore, since the tapered portion 8, 9 is provided in the suction surface 3 on the suction surface side in three directions, the shape of the contact surface 1 is smooth, so that the characteristic peeling on the suction surface side of the blade 2 is not promoted. As a result, there is very little increase in noise. Therefore, the low noise effect of the thick airfoil can be maintained as it is.
JP-A-7-189985

  The effect of the agitation of the blower impeller according to the prior art can be useful for weight reduction. However, the low noise effect and the effect of improving the air flow performance of the thick blade type impeller are reduced. In other words, when the eggplant is put on the suction surface side, some peeling is promoted, and turbulence is generated thereby leading to deterioration of the air flow performance. Moreover, the noise increases slightly due to turbulent noise. Furthermore, since the thickness of the blade always changes and the thickness of the tip portion (outer peripheral portion) of the impeller is large only with this technique, the productivity (resin molding) is deteriorated.

  An object of this invention is to provide the air blower impeller which can suppress the said conventional problem even if it reduces in weight.

  In order to solve the above problems, a blower impeller of the present invention has a hub that is rotationally driven by receiving a rotational force from the outside, and a plurality of blades that extend radially around the hub, In the cross-sectional shape of the blade in the circumferential direction, the front edge side is formed in an airfoil shape, and the rear edge side is formed in a constant thickness shape. As a result, it is possible to reduce the weight of the blade compared to a thick blade having an airfoil shape as a whole. It is suppressed and the turbulence is reduced, and the air flow performance does not deteriorate. Furthermore, the fluid noise generated from the leading edge is also reduced. In addition, the blade has a constant thickness on the trailing edge side, which facilitates resin molding and enables stable molding and production.

  In the blower impeller of the present invention, it is possible to suppress deterioration in air flow performance or increase in turbulent noise by reducing the weight of the blades, and to suppress deterioration in productivity.

The first invention has a hub that is rotationally driven by receiving a rotational force from the outside, and a plurality of blades extending radially around the hub. In the circumferential cross-sectional shape of the blade, The blower impeller is characterized in that a leading edge side is formed in an airfoil shape and a trailing edge side is formed in a constant thickness shape. Thereby, the leading edge separation of the airflow is suppressed, the turbulence is reduced, the air flow performance is improved, the fluid noise is further reduced, and the noise is reduced. On the trailing edge side, the blades have a constant thickness, and stable molding and production are possible.

  According to a second aspect of the present invention, in particular, in the first aspect, the airfoil shape on the leading edge side is formed to a position of 50% to 85% from the leading edge to the trailing edge of the blade. It is. Thereby, the leading edge separation of the airflow is considerably suppressed, and the airflow performance can be improved and the noise can be reduced.

  A third aspect of the invention is a blower impeller characterized in that, in the first or second aspect of the invention, the cross-sectional shape in the vicinity of the trailing edge of the blade is formed into a gradually thinning shape. As a result, the trailing edge separation of the airflow is suppressed, the turbulence is reduced, and the airflow performance can be improved and the noise can be reduced.

  The fourth invention is characterized in that, in any one of the first to third inventions, the thickness of the base of the blade at the joint with the hub is formed large in the airfoil-shaped portion of the leading edge of the blade. It is a blower impeller. As a result, the strength is increased, and the blower impeller is strong against the centrifugal force during rotation.

  Embodiments of the present invention will be described below with reference to FIGS.

(Embodiment 1)
FIG. 1 is a perspective view of a blower impeller according to Embodiment 1 of the present invention. 2 is a side view of the blower impeller, FIG. 3 is a front view of the blower impeller, and FIGS. 4 and 5 are circumferential directions substantially along an equal flow line A1-A2 on the blades of the blower impeller. A cross-sectional shape is shown.

  1 to 3, the blower impeller 2 is provided with a plurality of blades 4 (three) on a substantially cylindrical hub 3. In the present embodiment, the hub is cylindrical, but the present invention is not limited to this, and a truncated cone-shaped hub or a combination of a cylindrical shape and a truncated cone shape may be used.

  Each of the blades 4 is formed into an airfoil shape whose thickness changes from a leading edge 5 on the windward side to a trailing edge 6 on the leeward side to a position 5M (5M (50%), 5M (85%)) with a thickness. The portion from the position 5M to the rear edge 6 is formed with a constant thickness. As shown in FIG. 3, the triangular tip portion 4a formed to protrude forward on the outer peripheral side of the front edge 5 is ignored, and the front edge 5 is considered as a straight line, and the position 5M is the outer periphery from the inner peripheral side of the blade 4. The same ratio is formed up to the side.

  4 and 5 show specific cross sections. In FIG. 4, the position of 50% of the chord length from the leading edge 5 to the trailing edge 6 of the blade 4 is defined as a position 5M (50%). 50%) is formed into an airfoil shape having a maximum wall thickness tmax. FIG. 5 shows that the position of 85% of the chord length from the leading edge 5 to the trailing edge 6 of the blade 4 is a position 5M (85%), and the maximum wall thickness tmax in the region up to the position 5M (85%). The airfoil shape is formed. All from the position 5M to the rear edge 6 are formed in a constant thickness shape (t1 = t2).

  With these shapes, the maximum thickness tmax is the same, and the blade 4 as a whole can be made thinner and lighter than a thick blade having an airfoil shape. With such a configuration, the leading edge separation of the air current is suppressed, and a smooth flow field is formed. Therefore, the air flow performance is improved and turbulent noise is reduced. In addition, it is not limited to forming the position 5M at the same ratio from the inner peripheral side to the outer peripheral side of the blade 4, but the ratio may be gradually changed from the inner peripheral side to the outer peripheral side.

It should be noted that leading edge peeling is likely to occur in a region within about 50% of the chord length from the leading edge to the trailing edge. Therefore, it is effective to make this region an airfoil shape in order to improve the air flow performance and reduce the turbulence noise by suppressing the leading edge separation of the air flow. Further, even if the region that is formed to have a constant wall thickness is configured as a position 5M that exceeds 85% of the chord length from the leading edge 5 to the trailing edge 6 of the blade 4, the entire shape is no longer an airfoil shape. There is almost no difference from the blades that were made, and it is not very effective. Accordingly, the position 5M is preferably 50% to 85% of the chord length from the leading edge 5 to the trailing edge 6 of the blade 4.

  Further, the trailing edge 6 is formed into a shape that gradually becomes thinner, such as an arc shape or an elliptical arc shape, as a cross-sectional shape. As a result, separation of the trailing edge of the airflow is suppressed, airflow performance is improved, and turbulent noise is reduced. Furthermore, since the shape of the tip is not an edge, stable molding is possible, and productivity is improved.

(Embodiment 2)
FIG. 6 is a perspective view of a blower impeller according to Embodiment 2 of the present invention, and FIG. 7 is a side view of the blower impeller. As in the first embodiment, the fan impeller 2 is provided with blades 4 on the hub 3 and is formed in an airfoil shape from the front edge 5 toward the rear edge 6 to a position 5M, and from the position 5M to the rear edge 6. It is formed in a constant thickness shape (t1 = t2).

  In FIG. 6, the thickness of the base portion 4b of the portion of the blade 4 formed in the airfoil shape to the hub 3 is increased. The base portion 4 b of the leading edge 5 of the blade 4 is the portion most easily broken when a large centrifugal force is applied to the blade 4 by the rotation of the blower impeller 2. Therefore, by increasing the thickness of the root portion 4b and reinforcing it, it is possible to suppress an increase in weight due to the wing shape, that is, a break due to an increase in centrifugal force during rotation. As shown in FIGS. 6 and 7, the reinforcement of the base portion 4 b of the blade 4 is effective even in the vicinity of the front edge 5. However, as shown in FIGS. 1 to 3, the entire base portion 4 b is reinforced. May be.

  As described above, in the fan impeller according to the present invention, in the fan impeller of the mixed flow fan and the axial flow fan, only the leading edge side of the blade is formed into an airfoil shape and the blast flow noise is improved. Reduction can be achieved. In addition, the stability of the productivity and weight reduction that are close to those of a blade having a constant thickness and a thin blade as a whole can be ensured. Furthermore, by increasing the strength of only the portion where the load is large, it can be applied to applications such as a light and strong mixed flow impeller.

The perspective view of the fan impeller in Embodiment 1 of this invention Front view of blower impeller in Embodiment 1 of the present invention Side view of blower impeller in Embodiment 1 of the present invention Sectional drawing of the blade | wing of the fan impeller in Embodiment 1 of this invention Sectional drawing of the blade | wing of the other air blower impeller in Embodiment 1 of this invention The perspective view of the fan impeller in Embodiment 2 of this invention Side view of blower impeller in Embodiment 2 of the present invention A perspective view of a conventional blower impeller Plan view of a conventional blower impeller Cross-sectional view of a conventional blower impeller Cross-sectional view of a conventional blower impeller

2 Blower impeller 3 Hub 4 Blade 4a Triangular tip part 4b Base part 5 Front edge 6 Rear edge

Claims (4)

It has a hub that is driven to rotate by receiving a rotational force from the outside, and a plurality of blades extending radially around the hub, and in the circumferential cross-sectional shape of the blade, the leading edge side is an airfoil shape A blower impeller characterized in that the rear edge side is formed in a constant thickness shape. The blower impeller according to claim 1, wherein the airfoil shape on the front edge side is formed to a position of 50% to 85% from the front edge to the rear edge of the blade. The blower impeller according to claim 1 or 2, wherein a cross-sectional shape in the vicinity of the trailing edge of the blade is formed into a gradually thinning shape. The blower impeller according to any one of claims 1 to 3, wherein a thickness of a base of the blade at a joint portion with the hub is formed large in an airfoil shape portion on a leading edge side of the blade.

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