WO2023162458A1

WO2023162458A1 - Ceiling fan

Info

Publication number: WO2023162458A1
Application number: PCT/JP2022/048080
Authority: WO
Inventors: 直希川村; 博之藤野
Original assignee: 東プレ株式会社
Priority date: 2022-02-25
Filing date: 2022-12-27
Publication date: 2023-08-31
Also published as: JP7445690B2; JP2023124173A

Abstract

A ceiling fan 10 comprises: a motor 20; a hub 30 which is disposed on a rotary shaft 22 that is rotated by the motor 20; and a plurality of blades 40 which are arranged radially about the hub 30. The blades 40 each have a plurality of wing portions 41a, 41b, 41c which are linearly arranged along the radial direction. The plurality of wings portions have the same wing cross section and are arranged at respective elevation angles α1, α2, α3 with respect to a plane PL orthogonal to the rotary shaft 22. The wing portions 41a, 41b, 41c of each of the blades 40 are arranged such that a wing portion at the radially inner side has a greater elevation angle than a wing portion at the radially outer side.

Description

ceiling fan

The present invention relates to ceiling fans.

Large ceiling fans are attached to the ceilings of factories, warehouses, etc. This is intended to agitate the air in a large space, improve the work environment, prevent condensation, and the like. In recent years, a ceiling fan has been developed that has a large diameter and blows a large amount of air over a wide area. Since the diameter of the ceiling fan is increased, a large amount of air can be generated even at a low rotation speed, which helps reduce noise.

JP 2019-74029 A JP 2007-182816 A

As the diameter of the ceiling fan increases, the speed difference between the radially arranged blades (blades) on the outer and inner sides increases. Therefore, for example, in a blade having the same cross section (same angle of attack) with respect to the longitudinal direction of the blade as disclosed in Patent Document 1, the peripheral speed is faster toward the outer peripheral side and a large lift is generated, and the reaction force is a high-speed wind. occurs downwards. On the other hand, on the inner peripheral side, the opposite is true, and low-speed wind is generated downward on the inner peripheral side. Therefore, by changing the angle of attack in the longitudinal direction of the blade, specifically, the angle of attack is made small on the outer peripheral side and increased on the inner peripheral side to equalize the lift in the longitudinal direction of the blade. , to regulate the amount of air generated when the blades rotate (see, for example, US Pat.

However, it is known that the air flowing through the blades will stall if the angle of attack of the blades is too large because the peripheral speed is even lower near the rotation axis (near the center of rotation) of the ceiling fan. A stall is a phenomenon in which when the flow velocity of the air flowing through the blade becomes low and the angle of attack becomes too large, the airflow flowing on the blade surface separates and the lift disappears (the lift coefficient decreases).

When the angle of attack is increased from 0° at a constant air speed, the lift coefficient gradually increases, but after the angle of attack at which the lift coefficient reaches its maximum, the aircraft descends (stalls). The angle of attack at which the lift coefficient is maximized is called the stall angle, and in a stall region larger than this stall angle, separation occurs in the airflow on the upper surface of the blade and the lift coefficient decreases. It was well known not to use blades at angles of attack in the stall region, as lift (lift coefficient) is reduced in the aforementioned stall region.

Therefore, in Patent Document 1, the wing portions of the blades are not arranged in the range of 10% to 30% of the diameter of the ceiling fan. As a matter of course, no descending wind is generated at a location where no blades are arranged (near the center of rotation of the ceiling fan). In addition, in Patent Document 2, blades are also arranged near the center of rotation of the ceiling fan, and it is described that an upward wind is generated near the center of rotation.

Therefore, an object of the present invention is to provide a ceiling fan that can generate descending wind even directly below the center of rotation of the ceiling fan and can make the wind speed uniform in the longitudinal direction of the blades.

A ceiling fan according to one aspect of the present invention includes a motor, a hub arranged on a rotating shaft rotated by the motor, and a plurality of blades radially arranged around the hub. The blade has a plurality of wing portions arranged linearly along the radial direction, the plurality of wing portions having the same airfoil cross-section, and facing a plane perpendicular to the axis of rotation. Each corner is provided and arranged. The plurality of wings of a blade are arranged with the angle of attack of the radially inner wing greater than the angle of attack of the radially outer wing.

According to the ceiling fan according to one aspect of the present invention, it is possible to generate descending wind even directly below the center of rotation of the ceiling fan, and to make the wind speed uniform in the longitudinal direction of the blades.

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

A ceiling fan according to the present embodiment will be described below with reference to the drawings.

[Structure of ceiling fan]
As shown in FIGS. 1 to 4, the ceiling fan 10 according to this embodiment includes a motor 20, a hub 30, and a plurality of blades 40. As shown in FIG. In FIG. 1, the arrow R indicates the direction of rotation of the blade 40 when generating a downdraft (descending wind). "Rear" is the rear side in the rotational direction R of the blade 40 . 2 to 4 also show the hub 30 and one blade 40 out of the plurality of blades 40. FIG.

The mount 11 of the ceiling fan 10 is suspended and fixed from the ceiling frame (not shown) of the building. A motor box 12 is connected (suspended and fixed) to the lower end of the pedestal 11 . Inside the motor box 12, a motor 20 as an electric motor that rotates a plurality of blades 40 and a gear box 21 as a speed reducer that reduces the rotation of the motor 20 are accommodated. 1, only the frame 13 of the motor box 12 is shown, and illustration of the outer panel is omitted.

The rotation of the motor 20 is decelerated by the gear box 21, and the hub 30 as the center of rotation arranged below the motor box 12 is rotated.

A hub 30 is connected to the gearbox 21 via a rotating shaft 22 (see FIGS. 3 and 4), and six blades 40 are radially arranged on the hub 30 at equal angles (60°). Three

blade portions

41a, 41b, and 41c are arranged on one blade 40 on a straight line extending outward from the center of the ceiling fan 10 in the radial direction. The outer diameter (diameter) D of the ceiling fan 10 is approximately 9.6 m, and the length of one blade 40 is approximately 4.5 m. Therefore, the length L of one

wing portion

41a, 41b, 41c is approximately 1.5 m.

Of the three

blades

41 a , 41 b , 41 c , the radially innermost (inner peripheral side) blade 41 c is arranged near the hub 30 . Specifically, the wing portion 41 c on the inner peripheral side is arranged at the same height as the mounting portion 31 of the hub 30 by contacting the mounting portion 31 of the hub 30 .

The hub 30 has six mounting portions 31 radially formed at equal angles (60°), and each mounting portion 31 receives a shaft portion 43 of a connecting member 42 attached to a wing portion 41c on the inner peripheral side. An insertion hole 32 is provided.

A connecting member 42 having a shaft portion 43, a holding portion 44, and a convex portion 45 is arranged at the radially inner end portion (inner peripheral side end portion) of the wing portion 41c on the inner peripheral side. 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.

A notch 33 is provided in each mounting portion 31 of the hub 30 . By engaging the notch 33 with the protrusion 45 of the connecting member 42, the shaft 43 of the connecting member 42 is prevented from rotating by the hub 30, and the hub 30 and the blade 40 can rotate integrally.

On the other hand, in a state in which the inner circumferential side wing portions 41c are sandwiched between the sandwiching portions 44 of the connecting member 42, the inner circumferential side wing portions 41c are attached to the connecting member 42 using the second fastening members 72 such as bolts and nuts. fixed against.

The three

wing portions

41a, 41b, and 41c of the blade 40 all have an airfoil cross section with the same cross section. In this embodiment, in consideration of the manufacturing cost, a plurality of (three in this embodiment) wings 41 (see FIG. 9) cut in advance from a drawn aluminum material to a length of 1.5 m are connected to form one A single blade 40 is constructed.

As shown in FIG. 9, the wing portion 41 has a wing upper surface 46a that curves upwardly convex and a wing lower surface 46b that curves upwardly concavely. Connecting

holes

47a and 47b through which a third fastening member 73 for fixing a winglet 60 (to be described later) is inserted are formed in the leading edge side portion and the trailing edge side portion of the wing portion 41, respectively. A cylindrical rib 48 and a plurality of angle-of-

attack setting holes

49a, 49b, and 49c for setting the angle of attack of the wing portion 41 are provided between the front and rear connecting

holes

47a and 47b of the wing portion 41. It is formed. These plurality of angle-of-

attack setting holes

49a, 49b, and 49c are formed at equal angles (5°) with respect to each other with the center of the axis of the cylindrical rib 48 as a reference.

As shown in FIGS. 2 to 4, at least between the ribs 48 of the radially

adjacent wings

41a, 41b, and 41c, a cylindrical member 34 made of glass fiber, for example, is spanned. Each

wing portion

41a, 41b, 41c is provided with a first communication hole portion 50 that communicates with the rib 48, and a mounting member (not shown) such as a flat screw is attached to the first communication hole portion 50. By screwing together, the cylindrical member 34 is fixed to each of the

wings

41a, 41b, 41c.

Also, a member 51 having a rectangular cross-section is bridged at least between the angle-of-

attack setting holes

49a, 49b, and 49c of the

wing portions

41a, 41b, and 41c adjacent in the radial direction. A second communication hole portion 52 communicating with the angle-of-attack

setting hole portions

49a, 49b, and 49c is provided in each of the

wing portions

41a, 41b, and 41c. By screwing an attachment 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 of the

wings

41a, 41b, 41c.

Furthermore, as shown in FIG. 10, the

blades

41a, 41b, and 41c have different angles of attack α1, α2, and α3 with respect to the plane of rotation (the plane PL orthogonal to the rotation axis 22). In this embodiment, the three

wings

41a, 41b, and 41c are arranged so that the angles of attack α1, α2, and α3 are 10°, 15°, and 20° from the outermost side. It is fixed while being rotated around the provided cylindrical rib 48 . That is, the plurality of

wing portions

41a, 41b, 41c of one blade 40 are arranged such that the angle of attack of the inner wing portion is larger than the angle of attack of the outer wing portion in the radial direction.

In each blade 40, the angle of attack α1 of the radially outermost (peripheral) blade portion 41a is 10°, the angle of attack α2 of the intermediate blade portion 41b is 15°, and the inner peripheral blade portion 41c is 20°. That is, the attack angle α3 of the radially innermost (inner peripheral side) blade portion 41c is larger than the attack angle α2 of the intermediate blade portion 41b. Furthermore, the angle of attack α2 of the intermediate blade portion 41b is greater than the angle of attack α1 of the radially outermost (peripheral) blade portion 41a. Therefore, the differences between the angles of attack α1, α2, and α3 of the radially

adjacent blade portions

41a, 41b, and 41c of the ceiling fan 10 are all the same angle (5°).

As shown in FIGS. 2 to 8, a winglet 60 as a wing end plate composed of a vertical plate is fixed at least to the radially outer end portion (outer peripheral end portion) of the wing portion 41a on the outer peripheral side. be. This winglet 60 has a rectifying effect.

In addition, in this embodiment, winglets 60 are also arranged between the radially

adjacent blade portions

41a, 41b, and 41c of the ceiling fan 10 . The winglets 60 fixed to the outer peripheral end or the inner peripheral end of the radially

adjacent wings

41a, 41b, 41c of the ceiling fan 10 are connected to each other using connecting members 74 such as bolts and nuts. .

As shown in FIG. 8, connection holes 61 for inserting the connection members 74 are provided in the upper and lower portions of the winglets 60, respectively. A front mounting hole 62 through which a mounting member (not shown) such as a flat screw is inserted is formed in the front portion of the winglet 60 for connection to the

wings

41a, 41b, and 41c. On the other hand, the rear portion of the winglet 60 has a plurality of rear mounting

holes

63a, 63b through which mounting members (not shown) such as flat screws are inserted for connection to the

wings

41a, 41b, 41c. , 63c are formed. Further, between the front mounting hole 62 and the

rear mounting holes

63a, 63b, 63c of the winglet 60, there are provided a first insertion hole 64 through which the aforementioned cylindrical member 34 is inserted, and A second insertion hole (not shown) through which the shaped member 51 is inserted is formed.

The front mounting hole portion 62 is formed as an elongated hole extending in an arc with the hole center of the insertion hole portion 64 as a reference. On the other hand, the plurality of

rear attachment holes

63a, 63b, 63c are formed at equal angles (5°) with respect to each other with the hole center of the insertion hole 64 as a reference.

[Setting the angle of attack of each wing]
FIG. 11 shows the relationship between the angle of attack and the lift coefficient at representative positions P1, P2, and P3 (see FIG. 4) of each

blade

41a, 41b, and 41c when the blade 40 is rotated at the rated speed (40 RPM). is a graph showing. In this graph, changes in the lift coefficients of the

wings

41a, 41b and 41c are indicated by lines labeled CL1, CL2 and CL3, respectively.

As described above, the angles of attack α1, α2, and α3 of the three

blades

41a, 41b, and 41c are set to 10°, 15°, and 20° in order from the outer peripheral side. For example, when the ceiling fan 10 according to the present embodiment is rotated at 40 RPM (revolutions per minute), the representative speeds of the outer, intermediate, and

inner blades

41a, 41b, and 41c are 19.6 m/min. s, 10.4 m/s, and 3.9 m/s. 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 changes in lift coefficient in each of the

wing portions

41a, 41b, and 41c is that as the angle of attack increases from 0°, the lift coefficient also increases, but the wing portion When the stall point is exceeded, the lift coefficient drops once. However, when the angle of attack is further increased, the lift coefficient turns to increase and sometimes exceeds the lift coefficient at the stall point.

For example, a case where the angles of attack α1, α2, and α3 of the three

blades

41a, 41b, and 41c are all set to the same angle, specifically, a case where the angles of attack are all 10° will be described. The lift coefficients of the

wings

41a, 41b, and 41c at that time are the values indicated by points A, B, and C, respectively. Point A and point B have the same value, but it can be seen that the lift coefficient of point C is considerably inferior to the others. That is, when the angle of attack α3 of the inner peripheral blade portion 41c is 10°, the lift coefficient is lowered and sufficient lift, that is, the wind speed (air volume) cannot be obtained.

However, by setting the angle of attack α3 of the wing portion 41c on the inner peripheral side to 20°, it is possible to obtain a lift coefficient substantially equal to that of the

other wing portions

41a and 41b. In other words, the blade 41c on the inner peripheral side can also obtain substantially the same wind speed (air volume) as the

other blades

41a and 41b.

As can be seen from FIG. 11, the angle of attack α3 of the wing portion 41c on the inner peripheral side is larger than the stall angle αs at which the stall occurs, and when the angle of attack is further increased beyond the stall angle αs, the lift coefficient increases again. It is set to be greater than the increasing angle αr. In addition, the angle of attack α3 of the wing portion 41c on the inner peripheral side is set to be larger than the angle of attack of the same value as the lift coefficient of the stall angle αs (angle indicated by point D, about 14°). Further, 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).

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

(1) The ceiling fan 10 according to the present embodiment includes a motor 20, a hub 30 arranged on a rotating shaft 22 rotated by the motor 20, and a plurality of blades 40 radially arranged around the hub 30. Prepare. The blade 40 has a plurality of

wings

41a, 41b, 41c linearly arranged along the radial direction. The plurality of

blade portions

41a, 41b, and 41c have the same blade cross-section and are arranged at angles of attack α1, α2, and α3 with respect to a plane PL perpendicular to the rotating shaft 22, respectively. The plurality of

wings

41a, 41b, and 41c of one blade 40 are arranged such that the angle of attack of the inner wings is larger than the angle of attack of the radially outer wings.

That is, the attack angle α3 of the radially innermost (inner peripheral side) blade portion 41c is greater than the attack angle α2 of the intermediate blade portion 41b. Furthermore, the angle of attack α2 of the intermediate blade portion 41b is greater than the angle of attack α1 of the radially outermost (peripheral) blade portion 41a. In this way, in each blade 40, the wing on the outer peripheral side has a small angle of attack and the wing on the inner peripheral side has a large angle of attack, and by equalizing the lift in the longitudinal direction of the blade 40, It is possible to adjust the amount of air generated when the blade 40 rotates.

(2) The angle of attack α3 of the wing portion 41c arranged on the innermost side in the radial direction (on the inner peripheral side) is a stall in which the lift coefficient decreases when the angle of attack is increased in the wing portion 41c when the blade 40 rotates. occurs and is greater than the angle αr at which the lift coefficient increases again if the angle of attack is made even greater than the stall angle αs.

In the inner peripheral side blade portion 41c, the lift coefficient is low at low airflow, and the stall starts even at a small angle of attack. Therefore, the inner peripheral wing 41c can obtain a lift coefficient similar to that of the outer peripheral wing 41a (attack angle α1=10°) and intermediate wing 41b (attack angle α=15°). can.

In short, the angle of attack α3 of the blade 41c on the inner peripheral side of the blade 40 of the ceiling fan 10 is made larger than the angle at which the stall occurs in the blade 41c (stall angle αs), so the lift coefficient increases. , can generate descending winds even at low speeds.

(3) The radially innermost (inner peripheral side) wing portion 41 c is arranged at the same height as the mounting portion 31 of the hub 30 by contacting the mounting portion 31 of the hub 30 .

By arranging the blades 41c on the inner peripheral side of the blades 40 of the ceiling fan 10 near the hub 30, it is possible to generate downward wind directly below the center of rotation of the ceiling fan 10 (hub 30). As a result, it is possible to send the descending wind substantially evenly to all the lower regions where the blades 40 rotate.

The inner peripheral blade plate (inner peripheral region) disclosed in Patent Document 2 (Japanese Patent Application Laid-Open No. 2007-182816) has a large angle of attack as in the above-described embodiment. However, the inner peripheral blade plate (inner peripheral region) and the hub (rotating portion) of Patent Document 2 are connected via an arm portion, and the inner peripheral blade plate (inner peripheral region) and the hub (rotating portion) are connected to each other. department) is maintained. Furthermore, the inner peripheral blade plate (inner peripheral region) of Patent Document 2 is arranged at a position lower than the hub (rotating portion). In Patent Document 2, there is a gap (distance) between the inner peripheral blade plate (inner peripheral region) and the hub (rotating portion). For this reason, an upward wind is generated below the hub (rotating part) of the ceiling fan, and the inner peripheral blades are blown out from the gap between the inner peripheral blade plate (inner peripheral area) and the hub (rotating part). A wind that wraps around the top of the board can occur.

By the way, although the ceiling fan of the present invention has been described by taking the above embodiment as an example, it is not limited to this embodiment, and various other embodiments can be adopted without departing from the gist of the present invention.

10 Ceiling fan 20 Motor 22 Rotating shaft 30 Hub 31 Mounting portion 40

Blades

41, 41a, 41b, 41c Wing portion 60 Winglet PL Plane α1 Angle of attack α2 Angle of attack α3 Angle of attack

Claims

a motor;
a hub arranged on a rotating shaft rotated by the motor;
a plurality of blades radially arranged around the hub;
The blade has a plurality of wing portions arranged linearly along the radial direction,
the plurality of wing sections have the same airfoil cross-section and are arranged at respective angles of attack with respect to a plane perpendicular to the rotation axis;
The plurality of wing portions of one of the blades are arranged such that the angle of attack of the inner wing portion is larger than the angle of attack of the outer wing portion in the radial direction.
ceiling fan.
The angle of attack of the wing portion disposed on the innermost side in the radial direction is greater than the stall angle at which a stall occurs in which the lift coefficient decreases when the angle of attack is increased in the wing portion when the blade rotates, and , greater than the angle at which the lift coefficient increases again if the angle of attack is increased further above said stall angle;
A ceiling fan according to claim 1.
the radially innermost wing portion is arranged at the same height as the mounting portion of the hub by contacting the mounting portion of the hub;
A ceiling fan according to claim 1 or 2.