Ceiling fan

Abstract

To improve rigidity of connectin parts between vane parts and inhibit increase of the overall weight of blades in a ceiling fan in which the blades are formed in a split structure comprising the plurality of vane parts.SOLUTION: A ceiling fan 10 includes a motor 20, a hub 30 disposed on a rotary shaft 22 which is rotated by the motor 20, and blades 40 radially disposed around the hub 30. The blade 40 has a plurality of vane parts 41 disposed in a linear form along a radiation direction. The vane part 41 is provided with a circular hole part 48a penetrating through the vane part 41 along the radiation direction. At ends in the radiation direction in the vane part 41, vane end plate parts (winglets 60) each of which is perpendicular to the radiation direction are disposed. An insertion hole part 64 penetrating through the vane end plate part is formed at the vane end plate part. The vane end plate parts of the adjacent vane parts 41 are placed in contact with each other and fixed. Cylindrical members 34 each of which spans the circular hole parts 48a of the adjacent vane parts 41 and the insertion hole parts 64 of the vane end plate parts are disposed.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a ceiling fan. [Background technology]

[0002] Large ceiling fans are installed on the ceilings of factories, warehouses, etc. The purpose of these fans is to circulate the air in a large space, improving the working environment and preventing condensation. In recent years, ceiling fans with a larger diameter have been developed that can blow a large volume of air over a wide area. By increasing the diameter of the ceiling fan, it is possible to generate a large volume of air even at a low rotation speed, which also helps reduce noise. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2011-149300 A Summary of the Invention [Problem to be solved by the invention]

[0004] If the diameter of a ceiling fan is increased, it is possible to generate a large volume of wind, but the centrifugal force acting on the blades (wings) with a large diameter due to rotation is also large. Therefore, it is particularly required to increase the rigidity of the blades, but increasing the rigidity increases the weight, and there is a trade-off between rigidity and weight. In addition, if the blades have a divided structure consisting of multiple blades, as disclosed in Patent Document 1, for example, stress is likely to concentrate at the joints between the blades, and there is a possibility that the joints between the blades may be damaged.

[0005] Therefore, the present invention aims to provide a ceiling fan in which the blades have a divided structure consisting of multiple wing sections, which can increase the rigidity of the connection between the wing sections while suppressing an increase in the overall weight of the blade. [Means for solving the problem]

[0006] A ceiling fan according to one aspect of the present invention includes a motor, a hub disposed on a rotating shaft rotated by the motor, and a number of blades radially disposed about the hub. The blades have a number of blades linearly disposed along the radial direction. The blades have the same aerofoil cross sections and are disposed at angles of attack relative to a plane perpendicular to the rotating shaft, and the blades have circular holes formed therethrough in the radial direction. A blade end plate perpendicular to the radial direction is disposed at the end of the blade in the radial direction, and an insertion hole is formed in the blade end plate that penetrates the blade end plate. The blade end plates of adjacent blades are fixed to each other by abutting against each other, and a cylindrical member is disposed across the circular holes and the insertion hole in the blade end plate of the adjacent blades. Effect of the Invention

[0007] According to one aspect of the present invention, in a ceiling fan in which the blade has a divided structure consisting of multiple wing sections, it is possible to increase the rigidity of the connections between the wing sections while suppressing an increase in the overall weight of the blade. [Brief description of the drawings]

[0008] [Figure 1] 1 is a perspective view of a ceiling fan according to an embodiment of the present invention; [Diagram 2] FIG. 2 is a perspective view showing a main part of the ceiling fan shown in FIG. [Diagram 3] 3 is a plan view of the main part of the ceiling fan shown in FIG. 2. [Figure 4] 4 is a side view of the main part of the ceiling fan shown in FIG. 3. [Diagram 5] FIG. 5 is a cross-sectional view taken along line AA in FIG. [Figure 6] FIG. 5 is a cross-sectional view taken along line BB in FIG. [Figure 7] 5 is a cross-sectional view taken along line CC in FIG. 4. [Figure 8] FIG. 5 is a cross-sectional view taken along line DD in FIG. [Figure 9] FIG. 2 is a view of the airfoil of the blade viewed from the radial direction of the ceiling fan. [Figure 10] FIG. 4 is a diagram showing the relationship between the angles of attack of each wing portion. [Figure 11] 4 is a graph showing the relationship between lift coefficient and angle of attack for each wing portion. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, a ceiling fan according to this embodiment will be described with reference to the drawings.

[0010] [Ceiling fan configuration] As shown in Figures 1 to 4, a ceiling fan 10 according to this embodiment includes a motor 20, a hub 30, and a plurality of blades 40. In Figure 1, the rotation direction of the blades 40 when generating a downward air current (descending wind) is indicated by arrow R, and in the following description, "front" refers to the forward side of the rotation direction R of the blades 40, and "rear" refers to the rear side of the rotation direction R of the blades 40. In addition, Figures 2 to 4 show the hub 30 and one of the plurality of blades 40.

[0011] A stand 11 of the ceiling fan 10 is suspended and fixed to a ceiling frame (not shown) of a building. A motor box 12 is connected (suspended and fixed) to the lower end of the stand 11. Inside the motor box 12, a motor 20 serving as an electric motor for rotating the multiple blades 40 and a gear box 21 serving as a reducer for slowing down the rotation of the motor 20 are housed. Note that only the frame 13 of the motor box 12 is shown in FIG. 1, and the outer panel is not shown.

[0012] The rotation of the motor 20 is reduced in speed by the gear box 21, and causes a hub 30, which serves as a rotation center and is disposed below the motor box 12, to rotate.

[0013] A hub 30 is connected to the gearbox 21 via a rotating shaft 22 (see Figures 3 and 4), and six blades 40 are arranged radially on the hub 30 at equal angles (60°). Each blade 40 has three airfoils 41a, 41b, 41c arranged in a straight line extending outward from the radial center of the ceiling fan 10. The outer diameter D of the ceiling fan 10 is approximately 9.6 m, and the length of each blade 40 is approximately 4.5 m. Therefore, the length L of each airfoil 41a, 41b, 41c is approximately 1.5 m.

[0014] Of the three wings 41a, 41b, and 41c, the radially innermost (inner circumferential side) wing 41c is disposed in the vicinity of the hub 30. Specifically, the inner circumferential side wing 41c is disposed in contact with the mounting portion 31 of the hub 30 at the same height as the mounting portion 31 of the hub 30.

[0015] The hub 30 has six mounting portions 31 formed radially at equal angles (60°), and each mounting portion 31 is provided with an insertion hole portion 32 into which the shaft portion 43 of the connecting member 42 attached to the inner wing portion 41c is inserted.

[0016] A connecting member 42 having a shaft portion 43, a clamping portion 44, and a protrusion 45 is disposed on the radially inner end portion (inner end portion) of the inner wing portion 41c. The shaft portion 43 of the connecting member 42 is inserted into the insertion hole portion 32 described above, and the connecting member 42 is fixed to the hub 30 using a first fastening member 71 such as a bolt.

[0017] Further, each of the mounting portions 31 of the hub 30 is provided with a notch 33. When the notch 33 and the protrusion 45 of the connecting member 42 engage with each other, the shaft portion 43 of the connecting member 42 is prevented from rotating relative to the hub 30, and the hub 30 and the blade 40 can rotate integrally.

[0018] Meanwhile, with the inner wing portion 41c clamped by the clamping portion 44 of the connecting member 42, the inner wing portion 41c is fixed to the connecting member 42 using a second fastening member 72 such as a bolt and nut.

[0019] The three wing sections 41a, 41b, and 41c of the blade 40 all have the same airfoil cross section. In this embodiment, in consideration of manufacturing costs, a single blade 40 is constructed by connecting multiple wing sections 41 (see FIG. 9) (three in this embodiment) that are made by cutting a drawn aluminum material to a length of 1.5 m. The wing sections 41a, 41b, and 41c made of the drawn aluminum material have a uniform cross-sectional structure (cross-sectional shape) in the radial direction of the ceiling fan 10.

[0020] As shown in FIG. 9, the wing portion 41 has an upper wing surface 46a that is curved to be convex upward and a lower wing surface 46b that is curved to be concave upward. The leading edge side portion and the trailing edge side portion of the wing portion 41 are respectively formed with connecting holes 47a, 47b through which a third fastening member 73 such as a flat head screw for fixing a winglet 60 described later is inserted. In addition, between the front and rear connecting holes 47a, 47b in the wing portion 41, a cylindrical rib 48 having a circular hole 48a and a plurality of angle-of-attack setting holes 49a, 49b, 49c for setting the angle of attack of the wing portion 41 are formed. These plurality of angle-of-attack setting holes 49a, 49b, 49c are formed at equal angles (5°) with respect to each other with the axial center of the cylindrical rib 48 as a reference. In addition, the axial center of the cylindrical rib 48 (the hole center of the circular hole 48a) is set to substantially coincide with the aerodynamic center of the wing portion 41. For this reason, a circular hole 48a (described later) is formed substantially at the aerodynamic center of the wing portion 41 so as to penetrate from one end to the other end in the extension direction of the wing portion 41 (the radial direction of the ceiling fan 10).

[0021] 2 to 4, a cylindrical member 34 made of, for example, glass fiber (GFRP) is bridged between the ribs 48 (circular hole portions 48a; see FIG. 9) of at least radially adjacent wings 41a, 41b, 41c. Each of the wings 41a, 41b, 41c is provided with a first communication hole portion 50 communicating with the rib 48, and the cylindrical member 34 is fixed to each of the wings 41a, 41b, 41c by using mounting members (not shown) such as bolts and nuts in the first communication hole portion 50.

[0022] A cylindrical member 34 is disposed across the wing portion 41a and the wing portion 41b, and the cylindrical member 34 is fixed to the wing portion 41a at two first communication holes 50 using bolts and nuts, etc., and is fixed to the wing portion 41b at two first communication holes 50 using bolts and nuts, etc. A cylindrical member 34 is disposed across the wing portion 41b and the wing portion 41c, and the cylindrical member 34 extends from one end to the other end of the circular hole 48a of the wing portion 41c in the wing portion 41c disposed at the innermost side in the radial direction (the radial direction of the ceiling fan 10). The cylindrical member 34 is fixed to the wing portion 41b at two first communication holes 50 using bolts and nuts, etc., and is fixed to the wing portion 41c at six first communication holes 50 using bolts and nuts, etc.

[0023] A member 51 having a rectangular cross section is provided so as to span between the angle-of-attack setting holes 49a, 49b, and 49c of at least the radially adjacent blades 41a, 41b, and 41c. Each blade 41a, 41b, and 41c is provided with a second communication hole 52 that communicates with the angle-of-attack setting holes 49a, 49b, and 49c. By screwing a mounting member (not shown) such as a flat screw into the second communication hole 52, the member 51 having a rectangular cross section is fixed to each blade 41a, 41b, and 41c.

[0024] 10, the blades 41a, 41b, 41c have different angles of attack α1, α2, α3 with respect to the plane of rotation (plane PL perpendicular to the rotation axis 22). In this embodiment, the three blades 41a, 41b, 41c are fixed in a state of being rotated around a cylindrical rib 48 (circular hole 48a) provided on the blades 41a, 41b, 41c, so that the angles of attack α1, α2, α3 are 10°, 15°, 20° from the outermost side. That is, the blades 41a, 41b, 41c of one blade 40 are arranged such that the angle of attack of the inner blade is larger than the angle of attack of the outer blade in the radial direction (radial direction of the ceiling fan 10).

[0025] In each blade 40, the angle of attack α1 of the radially outermost (outer circumferential side) blade portion 41a is 10°, the angle of attack α2 of the middle blade portion 41b is 15°, and the angle of attack α3 of the inner circumferential side blade portion 41c is 20°. That is, the angle of attack α3 of the radially innermost (inner circumferential side) blade portion 41c is larger than the angle of attack α2 of the middle blade portion 41b. Furthermore, the angle of attack α2 of the middle blade portion 41b is larger than the angle of attack α1 of the radially outermost (outer circumferential side) blade portion 41a. Therefore, the differences between the angles of attack α1, α2, α3 of the blade portions 41a, 41b, 41c adjacent to each other in the radial direction of the ceiling fan 10 are all equal (5°).

[0026] 2 to 8, a winglet 60 is fixed as a blade end plate portion formed of a plate perpendicular to the extension direction of the blade portion 41a (the radial direction of the ceiling fan 10) at least to the radially outer end portion (the outer peripheral end portion) of the blade portion 41a on the outer peripheral side. The blade portion 41a and the winglet 60 are fixed by, for example, a welded portion 70 around the entire periphery (see FIG. 3). The winglet 60 has a straightening effect.

[0027] In this embodiment, winglets 60 are also disposed between (contact portions of) the blade sections 41a, 41b, 41c adjacent in the radial direction of the ceiling fan 10. The blade sections 41a, 41b, 41c and the winglets 60 are each fixed, for example, by a welded section 70 around the entire circumference (see Figs. 2 and 3). The winglets 60 fixed to the outer peripheral end or inner peripheral end of the blade sections 41a, 41b, 41c adjacent in the radial direction of the ceiling fan 10 are brought into contact with each other and connected (fastened) using connecting members 74 such as bolts and nuts.

[0028] As shown in Fig. 8, a peripheral portion (flange portion) of the winglet 60 is provided with a plurality of connection holes 61 (three in this embodiment) for inserting connection members 74 such as bolts and nuts. A front mounting hole 62 is formed in a front portion of the winglet 60, through which a third fastening member 73 such as a flat head screw is inserted for connection to the wing portions 41a, 41b, 41c. Meanwhile, a rear mounting hole 63a, 63b, 63c is formed in a rear portion of the winglet 60, through which a third fastening member 73 such as a flat head screw is inserted for connection to the wing portions 41a, 41b, 41c. Furthermore, a first insertion hole 64 through which the cylindrical member 34 described above is inserted and a second insertion hole (not shown) through which the cross-sectionally rectangular member 51 described above is inserted are formed between the front mounting hole 62 and the rear mounting hole 63a, 63b, 63c in the winglet 60.

[0029] The front mounting hole 62 is formed as an elongated hole extending in an arc shape with the hole center of the insertion hole 64 as the reference. On the other hand, the multiple rear mounting holes 63a, 63b, 63c are formed at equal angles (5°) to each other with the hole center of the insertion hole 64 as the reference.

[0030] [Setting the angle of attack for each wing] Fig. 11 is a graph showing the relationship between the angle of attack and the lift coefficient at representative positions P1, P2, and P3 (see Fig. 4) of each of the blades 41a, 41b, and 41c when the blade 40 is rotated at the rated speed (40 RPM). In this graph, the changes in the lift coefficient of each of the blades 41a, 41b, and 41c are indicated by lines labeled CL1, CL2, and CL3, respectively.

[0031] As described above, the angles of attack α1, α2, α3 of the three blades 41a, 41b, 41c are set to 10°, 15°, 20°, respectively, from the outer periphery. For example, when the ceiling fan 10 according to this embodiment is rotated at 40 RPM (revolutions per minute), the representative speeds of the outer periphery, middle, and inner periphery blades 41a, 41b, 41c are 19.6 m / s, 10.4 m / s, and 3.9 m / s, respectively. That is, the graph line CL1 of the change in lift coefficient shows the relationship between the angle of attack and the lift coefficient at 19.6 m / s, CL2 at 10.4 m / s, and CL3 at 3.9 m / s. What is common to the graph lines CL1, CL2, and CL3 of the change in lift coefficient of each blade 41a, 41b, 41c is that the lift coefficient increases as the angle of attack increases from 0°, but once the stall point of the blade is exceeded, the lift coefficient drops once. However, if the angle of attack is further increased, the lift coefficient begins to increase and may even exceed the lift coefficient at the stall point.

[0032] For example, let us consider a case where the angles of attack α1, α2, α3 of the three blades 41a, 41b, 41c are all the same, specifically, all angles of attack are 10°. The lift coefficients of the blades 41a, 41b, 41c at this time are the values ​​shown at points A, B, and C, respectively. It can be seen that points A and B have the same value, but the lift coefficient at point C is a significantly lower value than the others. In other words, when the angle of attack α3 of the inner blade 41c is 10°, the lift coefficient decreases and sufficient lift, i.e., wind speed (air volume), cannot be obtained.

[0033] However, by setting the angle of attack α3 of the inner wing portion 41c to 20°, it is possible to obtain a lift coefficient that is approximately the same as that of the other wing portions 41a and 41b. In other words, the inner wing portion 41c can also obtain approximately the same wind speed (air volume) as the other wing portions 41a and 41b.

[0034] As can be seen from Fig. 11, the angle of attack α3 of the inner wing portion 41c is set to be larger than the stall angle αs at which stall occurs and larger than the angle αr at which the lift coefficient increases again when the angle of attack is further increased from the stall angle αs. Moreover, the angle of attack α3 of the inner wing portion 41c is set to be larger than the angle of attack (the angle shown by point D, about 14°) that has the same value as the lift coefficient of the stall angle αs. Furthermore, the angle of attack α3 of the inner wing portion 41c is set to be larger than the angle of attack α1 of the outer wing portion 41a and the angle of attack α2 of the intermediate wing portion 41c (α3>α2>α1).

[0035] [Effects, etc.] The effects of this embodiment will be described below.

[0036] (1) The ceiling fan 10 according to this embodiment includes a motor 20, a hub 30 disposed on a rotary shaft 22 rotated by the motor 20, and a plurality of blades 40 radially disposed about the hub 30. The blades 40 have a plurality of wing portions 41a, 41b, and 41c linearly disposed along the radial direction. The plurality of wing portions 41a, 41b, and 41c have the same aerofoil cross sections, and are disposed with angles of attack α1, α2, and α3, respectively, with respect to a plane PL perpendicular to the rotary shaft 22. The wing portions 41a, 41b, and 41c are formed with circular holes 48a penetrating the wing portions 41a, 41b, and 41c along the radial direction. The wing portions 41a, 41b, and 41c are provided at the ends of the wing portions 41a, 41b, and 41c in the radial direction with wing end plate portions (winglets 60) perpendicular to the radial direction. The wing end plate portions are formed with insertion holes 64 penetrating the wing end plate portions. The blade end plates of adjacent blades 41a, 41b, 41c are abutted against each other and fixed, and a cylindrical member 34 is disposed across the circular hole 48a and the insertion hole 64 of the blade end plates of adjacent blades 41a, 41b, 41c.

[0037] A wing end plate portion (winglet 60) is provided at the end of each of the wing portions 41a, 41b, 41c, and the flange portions of these winglets 60 are abutted against each other and joined (fastened) by a plurality of connecting members 74. This prevents stress from concentrating on the connections between the wing portions 41a, 41b, 41c, and prevents the blades 40 from bending downward due to the weight of the wing portions 41a, 41b, 41c and the winglet 60, and also prevents bending in the rotational direction when the ceiling fan 10 is driven.

[0038] A GFRP cylindrical member 34 is disposed across the circular holes 48a of the adjacent wing sections 41a, 41b, 41c and the insertion hole 64 of the winglet 60. This increases the rigidity of the connections between the wing sections 41a, 41b, 41c while suppressing an increase in the weight of the entire blade 40 (hybrid effect).

[0039] (2) The angles of attack α1, α2, α3 of the wing portions 41a, 41b, 41c are set with the cylindrical member 34 as the center of rotation, and the radial ends of the wing portions 41a, 41b, 41c are connected to the wing end plate portion (winglet 60).

[0040] The blades 41a, 41b, 41c and the winglet 60 are provided with a circular hole 48a and an insertion hole 64, which are cylindrical cavities, respectively, and a cylindrical member 34 is inserted into the circular hole 48a and the insertion hole 64, making the blades 41a, 41b, 41c rotatable. The ends of the blades 41a, 41b, 41c are connected (fastened) and fixed to the winglet 60 by flat head screws or the like. This sets the angles of attack α1, α2, α3 of the blades 41a, 41b, 41c, and suppresses torsional vibration of the blades 41a, 41b, 41c when the ceiling fan 10 is driven.

[0041] (3) In the wing portion 41c that is located innermost in the radial direction, the cylindrical member 34 extends from one end to the other end of the circular hole portion 48a of the wing portion 41c, and the wing portion 41c and the cylindrical member 34 are fixed at multiple points along the radial direction.

[0042] Since the wing portion 41c arranged at the innermost position in the radial direction supports the weight of the wing portions 41b and 41a arranged on the outer side thereof, a large stress is applied to the wing portion 41c, and the blade 40 may be significantly deflected downward at the wing portion 41c. Therefore, by providing a plurality of fixing portions (six portions in this embodiment) between the wing portion 41c and the cylindrical member 34, the rigidity of the wing portion 41 can be increased and the downward deflection of the blade 40 can be suppressed.

[0043] (4) The multiple blades 41a, 41b, 41c of one blade 40 are arranged such that the angle of attack of the inner blades in the radial direction is greater than the angle of attack of the outer blades.

[0044] That is, the angle of attack α3 of the radially innermost (inner periphery) blade portion 41c is greater than the angle of attack α2 of the middle blade portion 41b. Furthermore, the angle of attack α2 of the middle blade portion 41b is greater than the angle of attack α1 of the radially outermost (outer periphery) blade portion 41a. In this way, by making the angle of attack smaller for the outer periphery blade portion and larger for the inner periphery blade portion in each blade 40, it is possible to equalize the lift in the longitudinal direction of the blade 40 and adjust the amount of air generated when the blade 40 rotates.

[0045] Incidentally, the ceiling fan of the present invention has been described using the above-mentioned embodiment as an example, but it is not limited to this embodiment and various other embodiments can be adopted without departing from the spirit of the present invention. [Explanation of symbols]

[0046] 10. Ceiling Fan 20 Motor 22 Rotation axis 30 Hub 34 Cylindrical member 40 Blades 41,41a,41b,41c Wing section 48a Circular hole 60 Winglet (wing end plate) 64 Insertion hole PL plane α1 Angle of attack α2 Angle of attack α3 Angle of attack

Claims

1. A motor; a hub disposed on a rotating shaft rotated by the motor; a plurality of blades arranged radially around the hub; The blade has a plurality of wing portions linearly arranged along a radial direction, The plurality of wing portions have the same aerofoil cross sections, and are arranged at angles of attack with respect to a plane perpendicular to the rotation axis, and a circular hole is formed in each of the wing portions, the circular hole penetrating the wing portion along the radial direction, A blade end plate perpendicular to the radial direction is disposed at an end of the blade in the radial direction, and an insertion hole penetrating the blade end plate is formed in the blade end plate, The blade end plate portions of the adjacent blade portions are abutted against each other and fixed to each other, and a cylindrical member is disposed across the circular hole portion of the adjacent blade portions and the insertion hole portion of the blade end plate portion. Ceiling fan.

2. The wing portion has an attack angle set with the cylindrical member as a rotation center, and an end portion of the wing portion in the radial direction and the wing end plate portion are coupled to each other.

2. The ceiling fan of claim 1.

3. The cylindrical member extends from one end to the other end of the circular hole of the wing portion disposed at the innermost side in the radial direction, and the wing portion and the cylindrical member are fixed at a plurality of points along the radial direction.

3. A ceiling fan as claimed in claim 1 or 2.

4. The plurality of wing portions of one of the blades are arranged such that an angle of attack of an inner wing portion is larger than an angle of attack of an outer wing portion in the radial direction.

3. A ceiling fan as claimed in claim 1 or 2.

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