JP5890972B2 - Centrifugal fan impeller - Google Patents

Description

  The present invention relates to an impeller for a centrifugal fan.

  Conventionally, for example, an impeller for a centrifugal fan that blows air to a heat exchanger in an air conditioning facility is known (see, for example, Patent Document 1).

  In the centrifugal fan impeller described in Patent Document 1, a reinforcing plate is joined to the radially outer end of the blade extending from the radially inner side to the outer side on the opposite side (curved inner side) of the rotational direction. Strength is improved.

Japanese Utility Model Publication No. 4-82399

  However, in such a conventional centrifugal fan impeller, since the air flow flowing along the front and back surfaces of the rotating blades is not taken into consideration, the total pressure efficiency (hereinafter referred to as the kinetic energy of the driving source) is converted into the energy of the air blow. , Also called general “blower efficiency”).

  Therefore, in view of such conventional problems, the present invention can improve the efficiency of the blower that converts the rotational kinetic energy of the drive source into the energy of the air while maintaining the weight reduction, the high strength, and the low cost. An impeller for a centrifugal fan is provided.

An impeller for a centrifugal fan according to the present invention includes a main plate connected to a drive source, a side plate opposed to the main plate at a predetermined interval and having a suction port, and a circumferential direction between the main plate and the side plate. A plurality of blades arranged at predetermined intervals along the blades, the blades are formed of steel plate panels , and each blade is a centrifugal fan impeller that is curved so that the rotation direction side is convex in a plan view. is there. A concave portion that is recessed toward the opposite side of the rotational direction of the blade is integrally formed on the radially inner side and the radially outer side of the blade, and the recessed portion formed on the radially outer side has an inner wall at least on the radially outer end. The air flowing through the concave portion on the outer side in the radial direction hits the inner side wall, and separation of the air occurs on the outer side in the radial direction of the inner side wall.

  According to the impeller for a centrifugal fan according to the present invention, the area of the peeling portion where the air flowing on the surface of the blade peels is reduced, and the efficiency of the blower that converts the rotational kinetic energy of the drive source into the energy of the air blow can be improved. it can. Moreover, since the recessed part is integrally formed by the press molding in the radial direction inner side and radial direction outer side to the blade | wing which consists of a steel plate panel, weight reduction, high intensity | strength, and inexpensive cost can be maintained.

FIG. 1 is a perspective view showing an impeller for a centrifugal fan according to the present invention. 2A is a perspective view showing a state in which the side plate is omitted from the centrifugal fan impeller shown in FIG. 1, and FIG. 2B is a cross-sectional view taken along line XX in FIG. 2A. . FIG. 3 is a plan view of FIG. FIG. 4 is a front view of the blade according to the present embodiment. FIG. 5 is a perspective view showing an impeller for a centrifugal fan according to a comparative example. 6A is a perspective view showing a state in which the side plate is omitted from the centrifugal fan impeller shown in FIG. 5, and FIG. 6B is a cross-sectional view taken along line YY of FIG. 6A. . FIG. 7 is a perspective view showing a separation portion of the air flow in the blade according to the present embodiment. FIG. 8 is a cross-sectional view of the peeling portion of FIG. FIG. 9 is a perspective view showing an air flow separation portion in a blade according to a comparative example. 10 is a cross-sectional view of the peeling portion of FIG. FIG. 11 is a graph showing the relationship between the static pressure and the air volume in the blade according to the present embodiment and the blade according to the comparative example. FIG. 12 is a graph showing the relationship between the total pressure efficiency and the air volume in the blade according to the present embodiment and the blade according to the comparative example.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  As shown in FIGS. 1 and 2, the centrifugal fan impeller 1 according to the present embodiment has a disk-shaped main plate 3 disposed on the lower side, and is directed upward (in the direction of the rotation axis of the impeller 1) from the main plate 3. And a disc-shaped side plate 7 having a suction port 5 at the center and a plurality of blades arranged between the main plate 3 and the side plate 7 at predetermined intervals along the circumferential direction. 9. The main plate 3, the side plate 7 and the blades 9 are all formed by press-molding a steel plate panel, and are joined together by welding, caulking, or the like.

  A central portion of the main plate 3 is formed in an annular portion 11 protruding upward, and a mounting port 13 to which a bush and a motor of a driving source (not shown) are connected is provided in the center of the annular portion 11. .

  The side plate 7 is formed in an annular shape, and the suction port 5 for taking in air is formed in the center. The suction port 5 is bent upward.

  As shown in FIG. 3, a plurality of the blades 9 (seven in this embodiment) are arranged. Each blade 9 extends from the radially inner side to the radially outer side, and is curved and formed with a certain curvature so that the clockwise direction that is the rotational direction is convex. Hereinafter, in the present specification, the curved outer side of the blade 9 is referred to as a front surface side, and the curved inner side is referred to as a back surface side.

  Further, as shown in FIGS. 2A and 2B and FIG. 4, the outer shape of the blade 9 is formed in a substantially rectangular shape, and a concave portion 10 having a substantially rectangular shape in front view is formed along the outer peripheral edge portion of the blade 9. It is formed continuously over the entire circumference by press molding. Specifically, the recess 10 is recessed toward the opposite side of the rotation direction of the blade 9 as shown in FIG. In other words, the shape of the blade 9 is recessed toward the back side of the curved inner side. Further, as shown in FIG. 4, the concave portion 10 is disposed on the radially inner side and extends in the vertical direction (rotation axis direction of the blade 9), and is disposed on the radially outer side in the vertical direction. From the extending outer concave portion 23, the upper concave portion 25 connecting the upper ends of the inner concave portion 21 and the outer concave portion 23, and the lower concave portion 27 connecting the lower ends of the inner concave portion 21 and the outer concave portion 23, the front concave portion is substantially rectangular. Is formed. The inner concave portion 21 extends linearly along the vertical direction, and the outer concave portion 23 extends linearly while inclining radially inward as it goes downward. The lower concave portion 27 extends linearly along the radial direction, and the upper concave portion 25 is curved downward in the radial center. As shown in FIG. 2B, when the impeller 1 rotates and air A flows on the front and back surfaces of the blade 9, the pressure on the outer surface side of the curved surface is higher than that on the rear surface side on the curved inner side. High pressure side.

  In the centrifugal fan impeller 1 having the above-described configuration, after taking in air A from the suction port 5 provided in the side plate 7, the air A is discharged radially outward through the plurality of blades 9.

  Next, a centrifugal fan impeller according to a comparative example will be described. In addition, the same code | symbol is attached | subjected about the component same as the impeller for centrifugal fans by this embodiment, and description is abbreviate | omitted.

  As shown in FIGS. 5 and 6, the centrifugal fan impeller 101 according to the comparative example is configured in substantially the same structure as the present embodiment, but the shape of the blade 109 is different.

  Specifically, as shown in FIGS. 6A and 6B, the recess 110 is formed over the entire outer peripheral edge of the blade 109. That is, the recess 110 includes an inner recess 121 that is disposed on the radially inner side and extends in the vertical direction (rotary axis direction of the blade), an outer recess 123 that is disposed on the radially outer side and extends in the vertical direction, The upper concave portion 125 connecting the upper ends of the inner concave portion 121 and the outer concave portion 123 and the lower concave portion 127 connecting the lower ends of the inner concave portion 121 and the outer concave portion 123 are formed in a substantially rectangular shape in front view. However, since the recessed part 110 is dented toward the surface side which becomes the rotation direction side of the blade | wing 109, this denting direction is a direction opposite to this embodiment.

  Next, the air flow which flows on the surface of a blade | wing is demonstrated by contrasting this embodiment and a comparative example. As described with reference to FIG. 2B, the air flow on the surface side will be described because the blade side has a higher pressure and has a higher contribution rate to the fan efficiency described later.

  In the present embodiment, an air peeling portion 31 is generated in the outer concave portion 23 surrounded by a one-dot chain line in FIG. Specifically, as indicated by the arrows in FIG. 8, the air A that has moved the surface 33 of the blade 9 toward the radially outer side slightly turns around into the outer recessed portion 23, and the radially outer end of the outer recessed portion 23. In this case, the air A hits the inner wall 23a of the outer recess 23 and causes separation. However, as shown in FIG. 7, the position of the peeling portion 31 moves in the radially outer end direction as compared with the comparative example described later, and thus the effective area of the blades contributing to the aerodynamic power is expanded. Moreover, since a peeling part does not generate | occur | produce in the inner side recessed part 21, there also exists a reduction of the frictional force by the reduction | decrease of a peeling part, and a performance improves.

  On the other hand, in the comparative example, separation portions 135 and 137 of air A are generated in the inner recess 121 and the outer recess 123 surrounded by the one-dot chain line in FIG. Specifically, as shown by the arrows in FIG. 10, the air A that has moved the surface 133 of the blade 109 toward the radially outer side hits the wall 121a on the back surface side (rotational direction side) of the inner recess 121 and the air A Causes peeling. Further, also in the outer recessed portion 123, the air A hits against the wall on the back surface side (rotational direction side) of the inner recessed portion 121 and the air A is peeled off. Therefore, as shown in FIG. 9, the effective area that becomes a normal flow without causing separation is smaller than that of the present embodiment.

  As shown in FIG. 11, the impeller according to the present invention has a higher static pressure with respect to the air volume in the normal use range than the comparative example.

  Also, as shown in FIG. 12, the impeller according to the present invention has a greater total pressure efficiency with respect to the air volume in the normal use range than the comparative example. Here, the total pressure efficiency (%) is based on JIS B8330 “Blower Test and Inspection Method” and is defined by total pressure aerodynamic power (kW) ÷ shaft power (kW). The total-pressure aerodynamic power is the energy of the wind of the air discharged from the blades, and the axial power is the energy that rotates the blades by the drive source. That is, the total pressure efficiency is an efficiency for converting the rotational kinetic energy of the driving source into the energy of the air blow, and the higher the total pressure efficiency, the more energy is saved.

  By the way, although this invention was demonstrated taking the example for the said embodiment, various changes are possible in the range which is not restricted to this embodiment and does not deviate from the summary of this invention.

  Next, the function and effect of this embodiment will be described.

(1) A centrifugal fan impeller 1 according to the present embodiment includes a main plate 3 connected to a driving source, a side plate 7 that is disposed to face the main plate 3 at a predetermined interval, and has a suction port 5. A plurality of blades 9 arranged at predetermined intervals along the circumferential direction between the main plate 3 and the side plate 7, and the blades 9 are formed by press-forming a steel plate panel. It is curved so that the rotation direction side is convex as viewed. An inner recess 21 and an outer recess 23 that are recessed toward the opposite side of the rotation direction of the blade 9 are integrally formed on the radially inner side and the radially outer side of the blade 9 by press molding.

  Therefore, the area of the separation portion 31 where the air A flowing on the surface 33 of the blade 9 separates is reduced, the loss of the air flow is reduced, and the efficiency of the blower that converts the rotational kinetic energy of the drive source into the energy of the air blow is improved. Can do. Moreover, since the inner recessed part 21 and the outer recessed part 23 are integrally formed by press molding in the blade | wing 9 which consists of a steel plate panel, weight reduction, high intensity | strength, and inexpensive cost can be maintained.

  (2) The recess 10 of the blade 9 is formed over the entire circumference of the outer peripheral edge of the blade 9. Accordingly, the strength of the blade 9 is further increased, and the durability of the impeller 1 is improved.

DESCRIPTION OF SYMBOLS 1 ... Centrifugal fan impeller 3 ... Main plate 5 ... Suction port 7 ... Side plate 9 ... Blade 10 ... Recess 21 ... Inner recess (recess)
23 ... Outer recess (recess)

Claims (2)

A main plate connected to the drive source, a side plate opposed to the main plate at a predetermined interval and having a suction port, and a plurality of the main plate and the side plate are arranged at a predetermined interval along the circumferential direction. Each blade is formed of a steel plate panel , and each blade is a centrifugal fan impeller that is curved so that the rotational direction side thereof is convex in plan view,
In a radially inner and radially outer of the vane, recess recessed toward the opposite side of the rotational direction of the blades are integrally formed,
The recess formed on the radially outer side includes an inner wall at least on the radially outer end,
An impeller for a centrifugal fan, wherein air flowing in the radially outer recess hits the inner wall, and air separation occurs on the radially outer side of the inner wall.   The impeller for a centrifugal fan according to claim 1, wherein the concave portion of the blade is formed over the entire circumference of the outer peripheral edge portion of the blade.

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