Axial fan

Abstract

The invention provides an axial fan, which can increase the air volume between the fan blades and improve the horsepower efficiency by improving the shape of the fan blades into a structure which does not vertically receive the flow of air or wind between the fan blades. Provided is an axial fan having a plurality of fan blades extending radially on the outer periphery of a hub, characterized in that: a tapered boss part at the root of a blade main body on the side facing the rear surface of an adjacent fan blade is formed into a shape having a wide surface inclined in the direction of rotation of the fan; the front end part of the downwind side of the fan blade is provided with a part bending towards the upwind side.

Description

TECHNICAL FIELD

[0001] The present application relates to an axial-flow fan for engine cooling, which is generally rotated by a driving force of an automobile engine or the like for cooling, and more particularly to an axial-flow fan having a plurality of fan blades extending radially on the outer periphery of a hub. BACKGROUND

[0002] As such a conventional axial-flow fan, there is known, for example, an axial-flow fan (see Patent Document 1) composed of a configuration in which a plurality of fan blades 12 extending radially are protruded on the outer periphery of a hub 11. Figure 6 As shown in an enlarged view, the fan blade 12 of such an axial-flow fan is formed in a configuration in which a blade side edge portion 12a composed of a vertical wall surface is integrally connected to a portion of a tapered boss portion 12b formed in a substantially L-letter shape (sickle shape) at the root of the blade main body, and is integrally protruded radially via a blade fixing portion 12c fixed to the hub 11 at right angles to the shaft center. Further, as shown in Figure 4 Figure 4 Figure 5 In the conventional axial-flow fan, the angle θ between the blade side edge portion 12a and the circular-arc-shaped portion of the blade 12 is substantially 90 degrees.

[0003] In the drawing, 12d is a blade leading edge, 12e is a blade trailing edge, 13 is a mounting member to a mating member, and 13a is a fastening bolt hole.

[0004] PRIOR ART DOCUMENTS

[0005] PATENT DOCUMENTS

[0006] Patent Document 1: Japanese Patent No. 63-25359 SUMMARY

[0007] PROBLEMS TO BE SOLVED BY THE INVENTION

[0008] However, the conventional axial-flow fan shown in Figure 4 Figure 5 has the following problems. That is, in Figure 4 Figure 5 ​​​​In the case of the axial fan shown, the tapered boss portion 12b and the blade leading edge 12d are superimposed when the fan blade is molded, so it is difficult to mold the blade by ordinary injection molding. Therefore, in the case of the conventional axial fan described above, it is necessary to form a blade side edge portion 12a composed of a vertical wall surface between the tapered boss portion 12b and the blade leading edge 12d to form a configuration that does not produce superimposition. However, in the case of the blade side edge portion 12a composed of a vertical wall surface, the vertical wall surface becomes a large resistance with respect to the flow of air or wind passing through this portion, so there is a disadvantage that the wind volume between the fan blades is reduced, resulting in low horsepower efficiency. In addition, in the fan blade of this axial fan, as shown in Figure 4 , Figure 5 The angle θ between the blade side edge portion 12a and the blade leading edge portion 12d is approximately 2 degrees, so it becomes a cause of reduction in the wind volume between the fan blades, resulting in a decrease in horsepower efficiency. In addition, the angle θ is an angle that is required as a general draft angle in resin molding.

[0009] The present application is completed to eliminate the disadvantages of the conventional axial fan described above, and to provide an axial fan that can achieve an increase in the wind volume between the fan blades and an improvement in horsepower efficiency by improving the shape of the fan blade to a configuration in which the flow of air or wind is not received vertically between the fan blades.

[0010] Solution to the problem

[0011] The axial fan of the present application has a plurality of fan blades extending radially on the outer periphery of a hub, characterized in that a tapered boss portion of a root portion of a blade main body on one side facing the back surface of an adjacent fan blade is formed in a shape having a wide surface inclined in the fan rotation direction, and a portion curved upward on the windward side is provided at the front end portion of the fan blade on the leeward side.

[0012] In addition, the taper angle θ of the leading edge of the root portion of the fan blade of this axial fan is generally approximately 2 degrees in the conventional leading edge, and in the present application, the taper angle θ of the leading edge is characterized in that it is 2 degrees or more and less than 90 degrees.

[0013] Effects of the invention

[0014] In the axial fan of the present application, the tapered boss portion of the root of the blade body is formed in a wide flat surface shape inclined to the fan rotation direction, so that the case where the flow of wind or air is received vertically between the fan blades is greatly reduced, the wind volume is increased, and the reduction of the horsepower increase amount due to the increase of the wind volume is achieved, and by providing the portion curved to the upwind side at the lower fan blade upwind side front end portion, the wind volume between the fan blades is increased, and the horsepower efficiency is improved. In addition, by making the tapered angle θ of the leading edge of the root of the fan blade 2 degrees or more and less than 90 degrees, the case where the flow of air or wind is received vertically between the fan blades hardly occurs, the wind volume between the fan blades is more effectively increased, and further improvement of the horsepower efficiency is achieved. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 is a main part enlarged perspective view showing an embodiment of the axial fan of the present application.

[0016] Figure 2 is a perspective view showing the state of the fan blade of the axial fan shown in Figure 1 .

[0017] Figure 3 is an explanatory view showing the leading edge tapered angle of the fan blade root of the axial fan shown in Figure 1 .

[0018] Figure 4 is a main part enlarged perspective view showing an example of the conventional axial fan which is the object of the present application.

[0019] Figure 5 is an explanatory view showing the leading edge tapered angle of the fan blade root of the conventional axial fan shown in Figure 4 .

[0020] Figure 6 is a front view showing a part of the conventional axial fan shown in Figure 4 . DETAILED DESCRIPTION

[0021] Hereinafter, an embodiment of the axial fan of the present application will be described with reference to the drawings.

[0022] Figure 1 The axial fan shown in Figure 4 has a plurality of fan blades 1 extending radially from the hub 11 in the same way as the conventional axial fan shown in Figure 1 , and is characterized in that Figure 2As shown, the fan blade 1 is configured such that a tapered boss portion 1a having a flat surface with a wide width inclined in the fan rotation direction is formed at the root of the fan blade 1 body on the side facing the back surface of the adjacent fan blade 1, and the tapered boss portion 1a is joined to the fan blade 1 body by a substantially triangular blade root 1b and a blade circular arc surface 1f. Further, a curved portion 1c curved toward the upwind side is formed at the upwind side front end of the fan blade 1. As shown, the inclination angle θ of the substantially triangular blade root 1b, that is, the tapered angle θ of the leading edge of the root of the fan blade 1, is 2 degrees or more and less than 90 degrees. Further, the tapered angle θ of the leading edge of the root of the fan blade 1 is 2 degrees or more and less than 90 degrees in order to reduce the case where the flow of air or wind is vertically received between the fan blades 1 and to more effectively achieve the increase in the amount of wind between the fan blades and the further improvement in the horsepower efficiency. Figure 3

[0023] Further, the fan blade 1 of the present application is of a unitary construction with a blade fixing portion 1d formed at the root of the blade body, and is configured by combining a tapered boss portion 1a having a flat surface with a wide width inclined in the fan rotation direction, a blade root 1b having a joining surface with the blade fixing portion 1d formed as a substantially triangular inclined surface, and a blade circular arc surface 1f formed between the tapered boss portion 1a and a blade inner wall surface 1e, and is configured such that a curved portion 1c curved toward the upwind side is provided at the upwind side front end of the fan blade 1. In the drawing, 1g is a blade leading edge, and 1h is a blade trailing edge.

[0024] Further, in the axial flow fan of this structure, the fan blade 1, the tapered boss portion 1a, the blade root 1b, the blade circular arc surface 1f, and the like are integrally provided by injection molding of a resin material or casting molding of aluminum or an aluminum alloy material, or the like.

[0025] In the axial flow fan of the above-described Figures 1-3 In the axial flow fan of the above-described embodiment, the tapered boss portion 1a of the root of the fan blade 1 body on the side facing the back surface of the adjacent fan blade 1 is formed in a shape having a flat surface with a wide width inclined in the fan rotation direction, and thus, the case where the flow of air or wind is vertically received between the fan blades 1 is significantly reduced, and the increase in the amount of wind and the reduction in the horsepower increase amount due to the increase in the amount of wind are achieved. Further, the curved portion 1c curved toward the upwind side provided at the upwind side front end of the fan blade 1 and the tapered angle θ (2 degrees or more and less than 90 degrees) of the leading edge of the root of the fan blade 1 enable the increase in the amount of wind between the fan blades and the improvement in the horsepower efficiency.

[0026] ​According to the inventor's experiments, for example, in a case where the axial flow fan according to the present application and a conventional axial flow fan are rotated at the same output (the same horsepower) and air is blown at the same vehicle resistance, the air volume is increased by 3 to 4% or more.

[0027] BRIEF DESCRIPTION OF DRAWINGS

[0028] 1, 12 fan blade

[0029] 1a conical boss portion

[0030] 1b blade root portion

[0031] 1c curved portion

[0032] 1d blade fixing portion

[0033] 1e blade inner wall surface

[0034] 1f blade circular arc surface

[0035] 1g blade leading edge

[0036] 1h blade trailing edge

[0037] 11 hub

[0038] 12a blade side edge portion

[0039] 12b conical boss portion

[0040] 12c blade fixing portion

[0041] 12d blade leading edge

[0042] 12e blade trailing edge

[0043] 13 mounting member (insert)

[0044] 13a fastening bolt hole

[0045] θ conical angle

Claims

1. A axial flow fan having a plurality of fan blades extending radially at an outer periphery of a hub, characterized in that, a tapered boss portion of a root of the blade body on a side facing a back surface of an adjoining fan blade is formed in a shape having a wide surface inclined to a fan rotation direction, and a portion curved to an upwind side is provided at a fan blade downwind side front end portion.

2. The axial flow fan according to claim 1, characterized in that, a tapered angle θ of a leading edge of the root of the fan blade is 2 degrees or more and less than 90 degrees.

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