JP6971960B2 - Propeller fan - Google Patents

Description

The present invention relates to a propeller fan with a plurality of blades.

A propeller fan provided with a plurality of blades as shown in Patent Document 1 is used in a residential ventilation fan or an industrial ventilation fan. Generally, a plastic material is used for a propeller fan used in a residential ventilation fan, and a metal material is used for a propeller fan used in an industrial ventilation fan.

Industrial ventilators use propeller fans at high rotational speeds to produce high air output. Also, it may be switched on and off frequently. In addition, it may be used in a drift state by being installed in the flow path. In order to withstand these usage environments, the propeller fan used in the industrial ventilation fan is required to have high strength.

For example, in a propeller fan used in an industrial ventilation fan, a spider provided in a portion close to a rotation axis where stress is likely to be concentrated is formed to have a thickness. On the other hand, the blade provided in the portion away from the rotation axis is formed thin. In this way, the strength is improved in the part where the stress is concentrated and the weight of the propeller fan as a whole is reduced.

Japanese Unexamined Patent Publication No. 2010-7602

However, forming the spider thicker in order to improve the strength of the spider may lead to an increase in the weight of the product and an increase in manufacturing cost.

The present invention has been made in view of the above, and an object of the present invention is to obtain a propeller fan capable of suppressing an increase in weight and an increase in manufacturing cost by improving the strength of a spider while suppressing the thickness. And.

In order to solve the above-mentioned problems and achieve the object, the present invention is a propeller fan that rotates around a rotation axis and blows air. The propeller fan has a boss portion that rotates around the rotation axis, a main plate that extends in a direction away from the rotation axis from the outer peripheral surface of the boss portion and is formed in an annular shape, and a direction away from the rotation axis from the outer peripheral edge of the main plate. A plurality of joints formed side by side along the outer peripheral edge of the main plate, a joint extending from each of the multiple joints in a direction away from the axis of rotation, and a plurality of blades joined to the joint. , Equipped with. The main plate is convex toward the downstream side of the blast, and is characterized in that an annular rib centered on the rotation axis is formed.

According to the propeller fan according to the present invention, it is possible to improve the strength while suppressing the increase in weight and the increase in manufacturing cost by suppressing the thickness of the spider.

A perspective view showing an electric motor and a propeller fan included in the ventilation fan according to the first embodiment of the present invention. Front view of the propeller fan according to the first embodiment Front view of the spider in the first embodiment Cross-sectional view taken along the line IV-IV shown in FIG. The figure which shows the relationship between the maximum stress ratio generated in a spider and a rib height ratio (h / t). The figure which shows the relationship between the maximum stress ratio generated in a spider and the rib outer circumference ratio (D2 / D1). The figure which shows the place where the maximum stress is generated in the spider when the propeller fan which concerns on Embodiment 1 is rotated. The figure which shows the strength analysis result at the time of rotating the propeller fan which concerns on Embodiment 1. The figure which shows the spider in the case of D2 / D1 = 0.915 which is the spider in Embodiment 1. FIG. Cross-sectional view taken along line XX of FIG. The figure which shows the strength analysis result when the propeller fan using the spider shown in FIG. 9 is rotated. Perspective view of the propeller fan according to the second embodiment of the present invention. Front view of the propeller fan according to the second embodiment Front view of the spider in the comparative example The figure which shows the strength analysis result of the spider shown in FIG. The figure which shows the strength analysis result of the spider shown in FIG. The figure which shows the relationship between the position where a through hole is formed and the maximum stress generated at the edge of a through hole. Perspective view of the propeller fan according to the third embodiment of the present invention. Front view of the propeller fan according to the third embodiment Cross-sectional view taken along the line XX-XX shown in FIG. Perspective view of the propeller fan according to the fourth embodiment of the present invention.

Hereinafter, the propeller fan and the ventilation fan according to the embodiment of the present invention will be described in detail with reference to the drawings. The present invention is not limited to this embodiment. For example, although the spider and the blade are separately configured as an example of the configuration of the propeller fan, the effect of the present invention can be obtained even in the configuration in which the spider and the blade are integrally molded.

Embodiment 1.
FIG. 1 is a perspective view showing an electric motor and a propeller fan included in the ventilation fan according to the first embodiment of the present invention. FIG. 2 is a front view of the propeller fan according to the first embodiment. The ventilation fan 50 includes an electric motor 30 and a propeller fan 40.

The electric motor 30 includes a housing 31 and a shaft portion 32. Inside the housing 31, a stator and a rotor (not shown) are provided. The rotor is rotatable about the rotation axis 9. The rotor rotates about the rotating shaft 9 by supplying electric power to the electric motor 30. The shaft portion 32 is connected to the rotor, and a part thereof is exposed from the housing 31. The shaft portion 32 has a rod-like shape extending along the rotation shaft 9, and rotates around the rotation shaft 9 together with the rotor.

The propeller fan 40 includes a boss portion 6, a spider 2, and a blade 1. The boss portion 6 is formed with a hole 6a through which the shaft portion 32 of the electric motor 30 penetrates. The shaft portion 32 of the electric motor 30 is inserted into the hole 6a of the boss portion 6, and the boss portion 6 is connected to the shaft portion 32.

FIG. 3 is a front view of the spider according to the first embodiment. The spider 2 has a main plate 3, a plurality of joint portions 23, and a plurality of joint portions 5. The main plate 3 is a plate-shaped member extending from the outer peripheral surface of the boss portion 6 in a direction away from the rotation shaft 9 and formed in an annular shape. The plate surface of the main plate 3 constitutes a surface perpendicular to the rotation axis 9. The boss portion 6 and the main plate 3 may be integrally formed, or a separately formed object may be joined by welding or the like.

The connecting portion 23 is formed so as to extend from the outer peripheral edge of the main plate 3 in a direction away from the rotation axis 9. The connecting portions 23 are formed so as to be arranged at equal intervals along the outer peripheral edge of the main plate 3. The number of connecting portions 23 matches the number of blades 1 described later. In the first embodiment, the number of connecting portions 23 is three.

The joint portion 5 is formed so as to extend from each of the plurality of joint portions 23 in a direction away from the rotation axis 9. The blade 1 is joined to the joint portion 5. The joint 5 and the blade 1 are joined by welding, caulking, or rivets. The blade 1 is a plate-shaped member formed thinner than the main plate 3. When viewed from a direction perpendicular to the rotation axis 9, the plate surface of the blade 1 is inclined with respect to the rotation axis 9. The propeller fan 40 has a three-dimensional three-dimensional shape.

In the propeller fan 40, the shaft portion 32 of the electric motor 30 rotates, so that the boss portion 6, the spider 2, and the blade 1 are integrated and rotate around the rotation shaft 9. As shown in FIG. 1, the propeller fan 40 rotates in the direction indicated by the arrow 8. When the propeller fan 40 rotates in the direction indicated by the arrow 8, an air flow in the direction indicated by the arrow 7 is generated. That is, the propeller fan 40 rotates in the direction indicated by the arrow 8 to blow air in the direction indicated by the arrow 7. In the following description, the direction indicated by the arrow 7 is the downstream direction, and the opposite direction is the upstream direction. Further, the surface of the main plate 3 facing the upstream direction is referred to as an upstream surface, and the surface facing the downstream direction is referred to as a downstream surface. Further, the direction indicated by the arrow 8 indicating the rotation direction is defined as the front in the rotation direction, and the opposite direction is defined as the rear in the rotation direction.

Next, the rib 4 formed on the main plate 3 will be described in detail. FIG. 4 is a cross-sectional view taken along the line IV-IV shown in FIG. The main plate 3 is formed with ribs 4 that are convex toward the downstream direction. As shown in FIG. 3, the rib 4 is formed in an annular shape when viewed along the rotation axis 9. In the first embodiment, the rib 4 is not formed in a certain region extending radially outward from the boss portion 6. That is, a region in which the rib 4 is not formed is provided between the inner peripheral edge of the rib 4 and the boss portion 6. As a method for manufacturing the spider 2 and the blade 1, a method of pressing a thin steel plate, a thin aluminum plate, or the like with a press to form the spider 2 and the blade 1 is often adopted. In the spider 2 formed by press working, the back surface side of the rib 4 has a concave shape. The spider 2 may be formed regardless of the press working so that the back surface of the rib 4 is not dented.

Here, as shown in FIG. 3, the outer diameter of the main plate 3 is D1, and the outer diameter which is the diameter of the outer peripheral edge of the rib 4 is D2. Further, the plate thickness of the main plate 3 is t, and the height of the rib 4 is h. As shown in FIG. 4, the outer peripheral edge of the rib 4 is a circle connecting the midpoint of the wall surface connecting the bottom surface of the recess on the downstream surface side formed by the formation of the rib 4 and the downstream surface of the main plate 3. ..

FIG. 5 is a diagram showing the relationship between the maximum stress ratio generated in the spider and the rib height ratio (h / t). The maximum stress ratio is the ratio of the maximum stress generated in the spider 2 having different rib height ratios when the maximum stress generated in the spider 2 in which the rib 4 is not formed is 1.

As shown in FIG. 5, it is possible to reduce the maximum stress under any condition under the condition where the rib 4 is formed, as compared with the case where the rib 4 is not formed. In particular, when the rib height ratio (h / t) ≧ 0.45, the maximum stress ratio becomes 0.8 times as compared with the case where the rib 4 is not formed, and the maximum stress can be greatly reduced. ..

However, when the rib height ratio (h / t) ≥ 1.2, the maximum stress reduction amount is almost constant, so that the rib height ratio (h / t) is maximum even if the rib height ratio (h / t) is increased by a certain value or more in terms of strength. The stress cannot be reduced, and when the rib height ratio (h / t) ≥ 2.0, the maximum stress ratio increases slightly.

FIG. 6 is a diagram showing the relationship between the maximum stress ratio generated in the spider and the rib outer circumference ratio (D2 / D1). As shown in FIG. 6, when D2 / D1 = 0.64 is used as a reference, the rib outer circumference ratio D2 / D1 ≧ 0.69 makes it possible to reduce the maximum stress by 5% or more, and the rib outer circumference ratio D2. / D1 is around 0.815 and the maximum stress ratio is 0.885, which is the minimum.

FIG. 7 is a diagram showing a location where the maximum stress is generated in the spider when the propeller fan according to the first embodiment is rotated. FIG. 8 is a diagram showing the strength analysis result when the propeller fan according to the first embodiment is rotated. In FIG. 8, the rotation speed of the propeller fan 40 having a blade outer diameter of φ815 mm, a blade 1 material of aluminum alloy, a plate thickness of 2.0 mm, a spider 2 material of high-strength steel, and a plate thickness of 4.5 mm. Shows the stress distribution generated in the spider 2 when rotated at 1200 (min ^-1). The darker the hatched area, the higher the stress is generated.

As shown in FIGS. 7 and 8, the maximum stress generation point 11 is the spider leading edge portion 10, which is the front edge portion in the rotational direction of the connecting portion 23, and is particularly the root portion close to the main plate 3. I understand.

FIG. 9 is a diagram showing a spider according to the first embodiment and in the case of D2 / D1 = 0.915. FIG. 10 is a cross-sectional view taken along the line XX of FIG. In this example, since the ratio of the rib 4 to the main plate 3 is large, the rib 4 approaches the connecting portion 23. Therefore, the stress is concentrated on the rib 4, and the stress cannot be reduced.

FIG. 11 is a diagram showing the strength analysis result when the propeller fan using the spider shown in FIG. 9 is rotated, and is a view of the spider viewed from the upstream side. In FIG. 11, it is shown that the darker the hatching, the higher the stress is generated. According to FIG. 11, it can be seen that the stress is concentrated on the rib 4.

In this way, the rate of stress reduction changes depending on the radial position of the rib 4. Further, when the rib outer peripheral ratio D2 / D1 is large, the region for pressing the outer peripheral portion of the spider 2 during the press working of the spider 2 is reduced, and the workability is deteriorated. Further, when the rib 4 and the connecting portion 23 are close to each other, the range to be machined is concentrated in a narrow range, and the workability is lowered. Due to these factors, when the rib outer circumference ratio D2 / D1 is large, there is a possibility that the dimensional accuracy is lowered, the manufacturing error is increased, and the cost is increased.

On the other hand, by setting the rib outer circumference ratio within the range exemplified in the above description, it is possible to suppress a decrease in dimensional accuracy, an increase in manufacturing error, and an increase in cost while reducing the maximum stress. Further, by setting the rib height ratio (h / t) within the range exemplified in the above description, the maximum stress can be further reduced. That is, it is possible to suppress the increase in weight and the increase in manufacturing cost by suppressing the thickness while improving the strength of the main plate 3.

In the first embodiment, the propeller fan 40 having three blades 1 is exemplified, but the number of blades 1 is not limited to three as long as it is plural.

Embodiment 2.
FIG. 12 is a perspective view of the propeller fan according to the second embodiment of the present invention. The same configurations as those of the first embodiment are designated by the same reference numerals, and detailed description thereof will be omitted. In the propeller fan 40 according to the second embodiment, a plurality of through holes 12 are formed in the rib 4. More specifically, a through hole 12 is formed in a flat surface portion which is the top of the rib 4. FIG. 12 shows an example in which circular through holes 12 are formed at three locations. The shape of the through hole 12 is not limited to this, and may be an ellipse, a polygon, or the like. Further, the number of through holes 12 is not limited to this, and may be two or four or more.

As shown in FIG. 12, by providing the through hole 12, the through hole 12 can be used for positioning during press working. This makes it possible to prevent the blank material from rotating during the press working of the spider 2, improve the molding accuracy of the joint portion 5 and the rib 4, and improve the manufacturing stability.

FIG. 13 is a front view of the propeller fan according to the second embodiment. Here, the boundary between the front edge of the connecting portion 23 and the main plate 3 is defined as the connecting portion front edge end 13, and the boundary between the trailing edge of the connecting portion 23 and the main plate 3 is defined as the connecting portion trailing edge end 14.

The through hole 12 has the trailing edge end 14 of the connecting portion, where θ is the angle formed by the line connecting the front edge end 13 of the connecting portion and the rotating shaft 9 and the line connecting the trailing edge end 14 of the connecting portion and the rotating shaft 9. It is formed in a region between the reference line 22 which is advanced by θ / 2 toward the front in the rotation direction and the line connecting the trailing edge end 14 of the connecting portion and the rotation axis 9. Is desirable.

FIG. 14 is a front view of the spider according to the comparative example. In the spider 62 according to the comparative example, the through hole 72 is formed further in front of the region in which the line connecting the trailing edge end 14 of the connecting portion and the rotation axis 9 is advanced by θ / 2 toward the front in the rotation direction. ..

FIG. 15 is a diagram showing the strength analysis result of the spider shown in FIG. FIG. 16 is a diagram showing the strength analysis result of the spider shown in FIG. In both FIGS. 15 and 16, the conditions shown in the first embodiment, that is, the blade outer diameter is φ815 mm, the blade material is aluminum alloy, the plate thickness is 2.0 mm, the spider material is high-strength steel, and the plate. The stress distribution generated in the spider when the propeller fan having a thickness of 4.5 mm is rotated at a rotation speed of 1200 (min ^{-1) is shown.}

As shown in FIG. 16, when the through hole 72 is formed on the front edge side of θ / 2 with respect to the arrow 8 in the rotation direction, a portion where stress is concentrated on the edge of the through hole 72 is generated. .. On the other hand, as shown in FIG. 15, when the through hole 12 is formed on the trailing edge side of θ / 2 with respect to the arrow 8 in the rotation direction, the through hole 12 is compared with the example shown in FIG. Stress is not concentrated at the edge of. In this way, by forming the through hole 12 on the trailing edge side of θ / 2 with respect to the arrow 8 in the rotation direction, it is possible to reduce the concentration of stress on the main plate 3.

FIG. 17 is a diagram showing the relationship between the position where the through hole is formed and the maximum stress generated at the edge of the through hole. Here, the positions where the through holes 12 and 72 are formed are defined by θ1. Let θ1 be the angle formed by the reference line 22 and the line connecting the centers of the through holes 12 and 72 and the rotation axis 9. Further, it is a condition that the angle is smaller toward the front edge side and the angle is larger toward the rear edge side with the reference line 22 as the boundary.

For example, assuming that the maximum stress generated in the through hole 72 at the position of θ = −38 ° is 1, the maximum stress generated in the through hole 12 formed at the position of θ1 = 21.8 ° is 0.457 times. It can be seen that the stress changes significantly.

As the stress generated in the through holes 12 and 72 becomes high, cracks and the like may be generated from the through holes 12 and 72. Therefore, as described above, it is desirable to form the through hole 12 on the trailing edge side of θ / 2 with respect to the arrow 8 in the rotation direction.

Embodiment 3.
FIG. 18 is a perspective view of the propeller fan according to the third embodiment of the present invention. FIG. 19 is a front view of the propeller fan according to the third embodiment. FIG. 20 is a cross-sectional view taken along the line XX-XX shown in FIG. The same configurations as those of the above-described embodiment are designated by the same reference numerals, and detailed description thereof will be omitted.

In the propeller fan 40 according to the third embodiment, the rib 4 is formed from the boundary between the main plate 3 and the boss portion 6. Further, an annular reinforcing plate 15 is provided outside the boss portion 6 which is a recessed portion of the rib 4. Unlike the first and second embodiments described above, even when the rib 4 is formed from the boundary between the main plate 3 and the boss portion 6, the strength of the spider 2 can be improved by providing the reinforcing plate 15. can. When the main plate 3 is recessed from the upstream side to form the rib 4 as in the third embodiment, as shown in FIG. 20, the thickness th of the reinforcing plate 15 is the same as the rib height h. It is desirable to reduce the unevenness on the upstream surface side.

In the propeller fan 40 according to the third embodiment, the rib 4 is not formed in a certain region from the boss portion 6 to the outside in the radial direction when the propeller fan 40 is large or due to the capacity of the press machine. Even when it is difficult to provide a region, it is effective in that the strength of the spider 2 can be improved.

Further, in the propeller fan 40 according to the third embodiment, the blade rib 17 extending along the blade leading edge 16 on the outer peripheral side of the joint portion 5 of the spider 2 is also formed in the blade 1. When the propeller fan 40 is large, a large stress is also generated in the blade 1. Therefore, the strength of the propeller fan 40 as a whole may be insufficient only by improving the strength of the spider 2. Therefore, by installing the blade rib 17 in the vicinity of the blade leading edge 16 where the strength is most required, it is possible to improve the strength at the stress generating portion. This makes it possible to reduce the plate thickness of the blade 1 and avoid the use of high-strength materials, and it is possible to reduce the manufacturing cost. In the present embodiment, the protrusion direction of the blade rib 17 is convex in the direction opposite to the direction of the arrow 7, but the same effect can be obtained even if the shape is convex in the same direction as the direction of the arrow 7.

Further, the position of the blade rib 17 of the blade leading edge 16 in the third embodiment is located between the spider 2 and the blade outer peripheral edge 18. Further, the intersection of the virtual line extending the blade outer peripheral edge 18 forward and the virtual line extending the blade leading edge 16 outward in the radial direction is defined as the blade leading edge portion intersection point 20, and the blade outer peripheral edge 18 and the blade trailing edge 19 Let the intersection of be the trailing edge intersection 21 of the blade. At this time, when the angle formed by the rotation axis 9 is θb, the blade rib 17 is located at the leading edge of the arrow 8 in the rotation direction rather than the position at θb / 2. It is desirable to reduce the stress of the blade 1.

Embodiment 4.
FIG. 21 is a perspective view of the propeller fan according to the fourth embodiment of the present invention. The propeller fan 40 according to the fourth embodiment has a configuration in which the blade rib 17 exemplified in the third embodiment is added to the blade 1 of the propeller fan 40 exemplified in the second embodiment.

The propeller fan 40 according to the fourth embodiment is not large enough to form the rib 4 from the boundary between the boss portion 6 and the main plate 3 as illustrated in the third embodiment, but a large stress is also generated on the blade. In the size propeller fan 40, it is possible to improve the strength while avoiding increasing the plate thickness and using a high-strength material, and it is possible to reduce the manufacturing cost.

The configuration shown in the above-described embodiment shows an example of the content of the present invention, can be combined with another known technique, and is one of the configurations as long as it does not deviate from the gist of the present invention. It is also possible to omit or change the part.

1 blade, 2 spider, 3 main plate, 4 rib, 5 joint, 6 boss, 6a hole, 7,8 arrow, 9 rotating shaft, 10 spider leading edge, 11 maximum stress generation point, 12 through hole, 13 connection Leading edge edge, 14 trailing edge edge of joint, 15 reinforcing plate, 16 blade leading edge, 17 blade rib, 18 blade outer edge, 19 blade trailing edge, 20 blade leading edge intersection, 21 blade trailing edge intersection, 22 Reference line, 23 connecting part, 30 electric motor, 31 housing, 32 shaft part, 40 propeller fan, 50 ventilation fan, 62 spider, 72 through hole.

Claims (5)

A propeller fan that rotates around a rotation axis and blows air.
The boss part that rotates around the rotation axis and
A main plate formed in an annular shape extending from the outer peripheral surface of the boss portion in a direction away from the rotation axis,
A plurality of connecting portions formed side by side along the outer peripheral edge of the main plate while extending in a direction away from the rotation axis from the outer peripheral edge of the main plate.
A joint extending from each of the plurality of joints in a direction away from the rotation axis,
With a plurality of blades joined to the joint,
The main plate is convex toward the downstream side of the blast and is formed with an annular rib centered on the rotation axis .
A plurality of through holes are formed in the rib, and the rib has a plurality of through holes.
The rotation direction of the propeller fan is the front, the opposite direction is the rear, the boundary between the front edge of the joint and the main plate is the front edge of the joint, and the boundary between the trailing edge of the joint and the main plate is the boundary. When the angle between the trailing edge of the connecting portion and the line connecting the leading edge of the connecting portion and the rotating shaft and the trailing edge of the connecting portion and the rotating shaft is θ.
The propeller fan is characterized in that the through hole is formed in a region where a line connecting the trailing edge of the connecting portion and the rotation axis is advanced by θ / 2 toward the front in the rotation direction. The propeller fan according to claim 1, wherein when the height of the rib is h and the thickness of the main plate is t, h / t ≧ 0.45. The propeller fan according to claim 1 or 2, wherein when the outer diameter of the main plate is D1 and the outer diameter of the rib is D2, D2 / D1 ≧ 0.69. The back surface of the rib is dented
The propeller fan according to any one of claims 1 to 3 , further comprising a reinforcing plate arranged on the bottom surface of the recess. The propeller according to any one of claims 1 to 4 , wherein a blade rib extending along a leading edge portion of the blade is formed between the outer peripheral edge of the blade and the joint portion. fan.

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