Propeller fan and method for manufacturing a propeller fan

Abstract

The objective is to provide a propeller fan and a method for manufacturing a propeller fan that reduces damage at the connection point between the hub and the blades by incorporating a smaller hub. [Solution] To achieve the above objective, a propeller fan according to one embodiment of the present invention is a propeller fan comprising a hub and a plurality of blades provided on the hub, wherein the hub is formed continuously from the peripheral wall of the hub and has a plurality of protrusions that project outward from the peripheral wall in the radial direction of the hub. With such a propeller fan, damage at the connection portion between the hub and the blades is further suppressed.

Description

Technical Field

[0001] The present invention relates to a propeller fan used in an outdoor unit of an air conditioner and a method for manufacturing the same.

Background Art

[0002] A propeller fan attached to an outdoor unit of an air conditioner includes a hub and a plurality of blades provided on the hub. The hub has a shape such as a cylindrical shape or a triangular prism shape, and has a peripheral wall and a pair of end face walls (front end face wall and rear end face wall) sandwiching the peripheral wall. Such a propeller fan is generally formed by injection molding using a mold and a resin material. There may be a gate trace remaining on the propeller fan due to injection molding. Further, in the outdoor unit of an air conditioner, since the propeller fan rotates at a high speed, it is required to ensure the necessary strength for the propeller hub (hereinafter simply referred to as the hub) of the propeller fan. As a technique for increasing the strength of the hub, there is a technique of providing a plurality of ribs in the hub from the central portion of the hub toward the peripheral wall of the hub (for example, Patent Document 1).

[0003] By providing such ribs on the hub, when the propeller fan rotates, a waviness phenomenon of the peripheral wall of the hub (a phenomenon in which the peripheral wall of the hub is deformed in a wave shape during the rotation of the propeller fan due to the stress caused by the centrifugal force due to the rotation of the propeller fan and the static pressure received by the blades during rotation (the reaction force received when the blades push out air)) is suppressed. A plurality of blades are provided on the peripheral wall of the hub. By suppressing the waviness phenomenon of the peripheral wall, it is possible to suppress the breakage of the hub itself and the occurrence of cracks at the connection portion between the hub and the blades.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Reducing the overall outer diameter of the hub is effective in suppressing the stresses mentioned above. By reducing the overall hub size without changing the outer diameter of the blades, the blade area increases, and the rotational speed can be reduced compared to when the blade area is smaller in order to obtain the same airflow, thus reducing the static pressure on the blades. In this way, reducing the outer diameter of the hub reduces stress, and thus suppresses the amplitude of the wave-like deformation mentioned above. When injection molding such a propeller fan, multiple injection points are positioned on the end face wall of the hub in order to distribute the resin material evenly to each of the multiple blades within the mold.

[0006] However, in such cases, a runner (a passage for the resin material in the mold) is provided for each gate from which the resin is injected in the mold. Therefore, the injection locations must be determined so that the runners do not interfere with each other. As a result, it is not possible to reduce the outer diameter of the hub to a certain size or smaller.

[0007] In view of the above circumstances, the object of the present invention is to provide a propeller fan and a method for manufacturing a propeller fan that further suppress damage at the connection point between the hub and the blades by incorporating a smaller hub. [Means for solving the problem]

[0008] To achieve the above objective, a propeller fan according to one embodiment of the present invention is: A propeller fan comprising a hub and a plurality of blades provided on the hub, The hub described above is formed continuously from the peripheral wall of the hub and has a plurality of protrusions that extend outward from the peripheral wall in the radial direction of the hub.

[0009] With this type of propeller fan, damage to the connection between the hub and the blades is reduced.

[0010] In the above propeller fan, Each of the above-mentioned multiple protrusions may have a gate mark.

[0011] In the above propeller fan, The number of the multiple protrusions and the number of the multiple wings are the same. Each of the above-mentioned multiple protrusions is connected to the above-mentioned peripheral wall, Each of the above-mentioned multiple blades may be formed in a continuous manner from the corresponding projection.

[0012] In the above propeller fan, Each of the above-mentioned multiple blades has a front end and a rear end at the base of the hub in the direction of rotation of the propeller fan. When the above-mentioned propeller fan is viewed from the front, each of the plurality of protrusions may be formed from the front end to the rear end in the direction of rotation.

[0013] In the above propeller fan, Any of the above-mentioned multiple protrusions may be positioned to correspond to the point where the stress on the hub is greatest as the vane rotates.

[0014] In the above propeller fan, Each of the above-mentioned multiple protrusions is, Each of the above-mentioned multiple wings has an inclined portion on which the base portion at the above-mentioned hub is provided, The wall portion formed from the above-mentioned inclined portion to the above-mentioned peripheral wall It has, When the above-mentioned propeller fan is viewed from the front, the wall portion and the rear ends of each of the multiple blades in the direction of rotation of the propeller fan may be formed in a continuous manner.

[0015] In the above propeller fan, The base portion of any of the multiple protrusions of any of the multiple blades has a front end and a rear end in the direction of rotation of the propeller fan. When the propeller fan is viewed from the front, the inclined portion may be formed so as to move away from the central axis of the propeller fan as it goes from the front end portion to the rear end portion.

[0016] In the above propeller fan, When the propeller fan is viewed from the front, the line of the root portion from the front end portion to the rear end portion may be a curve.

[0017] In order to achieve the above object, in the method for manufacturing a propeller fan according to one embodiment of the present invention, the above propeller fan is molded using a hot runner mold.

[0018] By such a manufacturing method, the above propeller fan is formed, and further, cost reduction can be achieved.

[0019] In the method for manufacturing the above propeller fan, A gate through which a resin material is injected may be provided corresponding to each of the plurality of protruding portions.

Effect of the Invention

[0020] According to the present invention, there are provided a propeller fan and a method for manufacturing a propeller fan in which breakage at the connection portion between the hub and the blades is more suppressed by providing a smaller hub.

Brief Description of the Drawings

[0021] [Figure 1] It is a schematic perspective view showing the appearance of an outdoor unit of an air conditioner including the propeller fan of the present embodiment. [Figure 2] It is a schematic perspective view of the propeller fan viewed obliquely from the front. [Figure 3] It is a schematic perspective view of the propeller fan viewed obliquely from the rear. [Figure 4] It is a schematic plan view of the propeller fan viewed from the front. [Figure 5]Figure (a) is a schematic side view showing the method for manufacturing a propeller fan according to this embodiment. Figure (b) is a schematic top view showing the method for manufacturing a propeller fan according to this embodiment. [Modes for carrying out the invention]

[0022] Embodiments of the present invention will be described below with reference to the drawings. XYZ axis coordinates may be included in each drawing. Furthermore, identical components or components with the same function may be denoted by the same reference numeral, and their description may be omitted as appropriate after their initial description. Also, the numerical values ​​shown below are illustrative and not limiting to this example.

[0023] (Outdoor unit of an air conditioner) Figures 1(a) and 1(b) are schematic perspective views showing the external appearance of the outdoor unit of an air conditioner equipped with a propeller fan according to this embodiment. Figure 1(a) shows the outdoor unit 10 of this embodiment viewed from the front at an oblique angle, and Figure 1(b) shows the outdoor unit with the fan guard 101g removed from Figure 1(a).

[0024] The housing 101 has a rectangular parallelepiped shape, for example, in which the length in the left-right direction is longer than the length in the front-back direction. The housing 101 is made of steel plate, for example, and has a top plate 101u, a bottom plate 101d facing the top plate 101u, and a side plate 101w provided between the top plate 101u and the bottom plate 101d.

[0025] In Figures 1(a) and 1(b), the Z-axis direction is the vertical direction of the outdoor unit 10, the X-axis direction is the left-right direction of the outdoor unit 10, and the Y-axis direction is the front-to-back direction (depth direction) of the outdoor unit 10. In this embodiment, the side of the top plate 101u of the housing 101 is the top or upper side of the outdoor unit 10, the side of the bottom plate 101d of the housing 101 is the bottom or lower side of the outdoor unit 10, the side of the housing 101 to which the fan guard 101g is attached is the front side of the outdoor unit 10, and the side opposite to the fan guard 101g in the Y-axis direction is the rear side of the outdoor unit 10. In the outdoor unit 10, the propeller fan 20 is positioned behind the fan guard 101g.

[0026] (Propeller fan) Figures 2(a) and 2(b) are schematic perspective views of the propeller fan viewed from the front at an oblique angle. Figure 2(a) shows the entire propeller fan, and Figure 2(b) shows the hub of the propeller fan. Figures 3(a) and 3(b) are schematic perspective views of the propeller fan viewed from the rear at an oblique angle. Figure 3(a) shows the entire propeller fan, and Figure 3(b) shows the hub of the propeller fan. The rotation direction 20R of the propeller fan 20 is clockwise in the front view in Figures 2(a) and 2(b), and counterclockwise in the rear view in Figures 3(a) and 3(b). The radial direction 20N of the propeller fan 20 is the direction radiating outwards from the central axis (rotation axis) 20c of the propeller fan 20.

[0027] As shown in Figures 2(a) and (b), the propeller fan 20 comprises a hub 30 and a plurality of blades 40. The plurality of blades 40 are provided on the hub 30. For example, the propeller fan 20 has three blades 40. In the rotation direction 20R, adjacent blades 40 are arranged at a 120° interval around the central axis 20c. The hub 30 has a bottomed cylindrical shape and has a base 31 and a plurality of protrusions 32.

[0028] The base body 31 has a peripheral wall 311, a central part 313 having an insertion hole 312, and a plurality of ribs 314a to 314f extending radially from the central part 313 (Figure 2(b)). The drive shaft (not shown) of a motor that rotates the propeller fan 20 is inserted into the insertion hole 312. When the propeller fan 20 is viewed from the front, the plurality of ribs 314a to 314f are spaced apart in the rotation direction 20R of the propeller fan 20. For example, of the plurality of ribs 314a to 314f, ribs 314a, 314c, and 314e extend from the central part 313 to the wall portion 322 of the protruding portion 32, which will be described later, and ribs 314b, 314d, and 314f extend from the central part 313 to the inclined portion 321 of the protruding portion 32, which will be described later.

[0029] Each of the multiple protrusions 32 is formed continuously from the peripheral wall 311 of the base body 31 in the hub 30. For example, the hub 30 is provided with three protrusions 32. Figure 2(b) shows the outer shape of the peripheral wall 311 when the propeller fan 20 is viewed from the front, as shown by a dashed line (dummy line 31L), when the protrusions 32 are not provided. When viewed from the front, the outer shape of the base body 31 when the multiple protrusions 32 are not provided (the shape of the ring connecting the dummy line 31L and the peripheral surface 311s of the peripheral wall 311) is approximately circular.

[0030] Each of the multiple protrusions 32 is connected to the peripheral wall 311. Each of the multiple protrusions 32 extends outward from the peripheral wall 311 in the radial direction 20N of the propeller fan 20. Each of the multiple protrusions 32 has an inclined portion 321 and a wall portion 322. The inclined portion 321 is formed convex in the radial direction 20N of the propeller fan 20. The inclined portion 321 is formed to move away from the center 313 as it extends from the peripheral wall 311 toward the rear in the rotation direction 20R of the propeller fan 20. For example, the inclined portion 321 is formed as a curved surface that extends from the boundary 301 between the peripheral wall 311 and the inclined portion 321 toward the center 313 in the radial direction 20N in the opposite direction to the rotation direction 20R. The wall portion 322 is formed from the rear end 3212 of the inclined portion 321 in the rotation direction 20R toward the peripheral wall 311. The wall portion 322 is erected continuously from the peripheral wall 311. For example, the wall portion 322 is formed to extend radially 20N from the front end 3111 of the peripheral wall 311 in the rotational direction 20R to the rear end 3212 of the inclined portion 321.

[0031] In the hub 30, the circumferential surface 311s of the peripheral wall 311, the inclined surface 321s of the inclined portion 321, and the wall surface 322s of the wall portion 322 are continuous with each other, thereby forming the outer circumferential surface 30s of the hub 30.

[0032] The multiple blades 40 are formed such that the number of blades 40 is equal to the number of multiple protrusions 32. Each of the multiple blades 40 is formed continuously from the corresponding protrusion 32. That is, each blade 40 and each protrusion 32 is arranged in a one-to-one relationship.

[0033] The inclined portion 321 of the protruding portion 32 has a base portion to which each of the multiple blades 40 is connected. In this embodiment, this portion is referred to as the base portion 41 (the portion shown by the dashed line A in Figures 2(a) and (b)). The base portion 41 of each of the multiple blades 40 at the hub 30 has a front end portion 411 and a rear end portion 412 behind the front end portion 411 in the rotation direction 20R of the propeller fan 20. Furthermore, each of the multiple blades 40 has an outer edge 42 that forms the edge in the radial direction 20N of the propeller fan 20, a front edge 43 that forms from the front end of the outer edge 42 to the base body 31 of the hub 30 in the rotation direction 20R, and a rear edge 44 that forms from the rear end of the outer edge 42 to the wall portion 322 of the hub 30 in the rotation direction 20R.

[0034] One of the multiple protrusions 32 is positioned to correspond to the point where the stress on the hub 30 is greatest due to the rotation of the blade 40. In other words, the point where the stress on the hub 30 is greatest due to the rotation of the blade 40 is included in the protrusions 32.

[0035] As shown in Figures 3(a) and (b), the back of the hub 30 is closed by a rear end wall 33. The rear end wall 33 has a base end wall 315 which is part of the base body 31 and a projection end wall 325 which is part of the projection 32 (Figure 3(b)). The base end wall 315 has a substantially circular planar shape. The base end wall 315 closes the base body 31 from the rear (back side) of the propeller fan 20. The projection end wall 325 has a triangular planar shape in which the vertex gradually approaches the central axis 20C as it moves in the direction opposite to the rotation direction 20R. The projection end wall 325 closes the projection 32 from the rear of the propeller fan 20. The projection end wall 325 is formed continuously from the base end wall 315 so as not to create a step between them. The rear end wall 33 is connected to the peripheral wall 311, the inclined portion 321, the wall portion 322, and the ribs 314a to 314f (Figure 2(b)).

[0036] Each of the multiple protrusions 32 has a gate mark 34 that remains after the propeller fan 20 is formed by injection molding. The gate mark 34 is formed at the corner 324 of the protrusion end face wall 325, sandwiched between the inclined portion 321 and the wall portion 322. For example, the gate mark 34 is formed at the corner 324 of the protrusion 32, sandwiched between the inclined portion 321 and the wall portion 322, near the boundary 323 where the inclined portion 321 and the wall portion 322 intersect (dashed line B in Figures 3(a) and (b)). Adjacent gate marks 34 in the rotational direction 20R are formed at 120° intervals.

[0037] Figure 4 is a schematic plan view of a propeller fan from the front. In Figure 4, the outline of a conventional hub is shown as a dashed line (dummy line 100L) as a reference example.

[0038] When the propeller fan 20 is viewed from the front, each of the multiple protrusions 32 is formed in the rotational direction 20R from the front end 411 to the rear end 412 of the base 41. The inclined portion 321 of the protrusion 32 is formed so that it moves away from the central axis 20c of the propeller fan 20 as it moves from the front end 411 to the rear end 412. By providing such protrusions 32 on the hub 30, the outer diameter dimension of the hub 30 other than the protrusions 32 (the outer diameter dimension of the peripheral wall 311 when the propeller fan 20 is viewed from the front) can be kept to approximately the outer diameter of the imaginary line 31L. Furthermore, by placing the gate marks 34 on the protrusions 32, that is, by placing the gate position during injection molding (described later) outside the imaginary line 31L, each gate can be provided without difficulty (without interfering with each other) in the mold for injection molding the propeller fan 20. In addition, the outer diameter of the hub 30 other than the corners 324 can be made shorter than in the reference example.

[0039] The rear ends 44 of each of the multiple blades 40 of the propeller fan 20 in the rotation direction 20R and the wall portion 322 are formed continuously without creating any steps. The line of the root portion 41 from the front end 411 to the rear end 412 (the dashed line A in Figures 2(a) and (b)) is curved. The inclined surface 321s of the inclined portion 321 on which the root portion 41 is provided is formed along the dashed line A (Figures 2(a) and (b)), and the front end 411 to the rear end 412 are smoothly connected by a curved surface.

[0040] (Manufacturing method for propeller fans) Figure 5(a) is a schematic side view showing the manufacturing method of the propeller fan according to this embodiment. Figure 5(b) is a schematic top view showing the manufacturing method of the propeller fan according to this embodiment. In Figure 5(b), the area around the hub 30 of the propeller fan 20 is shown.

[0041] The propeller fan 20 described above is formed by injection molding using a hot runner mold 5, which is equipped with an upper mold 5u and a lower mold 5d. In the hot runner mold 5, the gate 51 is positioned to correspond to the gate marks 34 of the propeller fan 20. That is, injection molding is performed by positioning a gate (runner) 51 into which the resin material is injected, corresponding to each of the multiple protrusions 32. For example, resin material is injected into the hot runner mold 5 from three locations, corresponding to the number of multiple protrusions 32.

[0042] Thermoplastic resins such as acrylic resin and polystyrene resin are used as the resin material. Long fibers having a needle-like or strip-like shape may be mixed into the thermoplastic resin in a predetermined proportion. Examples of long fibers include glass fibers, carbon fibers, and talc.

[0043] (action) In this embodiment, in the hot runner mold 5, the gate 51, which is the injection point, is positioned to correspond to the protrusion 32. This allows the outer diameter dimension of the hub 30 other than the protrusion 32 (the outer diameter dimension of the peripheral wall 311 when the propeller fan 20 is viewed from the front) to be kept to approximately the outer diameter of the imaginary line 31L. Furthermore, by placing the gate mark 34 on the protrusion 32, that is, by placing the gate position during injection molding (described later) outside the imaginary line 31L, each gate can be provided without difficulty (without interfering with each other) in the mold for injection molding the propeller fan 20. In addition, the outer diameter of the hub 30 other than the corner 324 of the protrusion 32 can be shortened (Figure 4). In such a propeller fan 20, as long as the dimension of the outer edge 42 of the propeller fan 20 from the central axis 20c does not change, the area of ​​the blades 40 increases in proportion to the shortened outer diameter of the hub 30, and the rotation speed can be set lower compared to the case where the blade area is small in order to obtain the same airflow. As a result, the static pressure on the hub 30 from the vane 40 is reduced. In addition, since the outer diameter of the hub 30 is shortened except for the corner portion 324 of the protruding portion 32, the undulation phenomenon in the hub caused by stress is suppressed. As a result, damage to the hub 30 is suppressed.

[0044] Furthermore, according to this embodiment, the gate 51, which is the injection point, is positioned to correspond to the protruding portion 32 (for example, the corner portion 324 of the protruding portion 32). This makes it possible to miniaturize the hub 30 without the gates 51 interfering with each other.

[0045] Furthermore, according to this embodiment, since the gate 51, which is the injection point, is positioned to correspond to the protrusions 32, during injection molding of the propeller fan 20, the resin material flowing in from the gate 51 flows sequentially to each of the multiple protrusions 32 and to the blades 40 corresponding to each protrusion 32. As a result, the resin material is evenly distributed to each of the multiple protrusions 32 and the multiple blades 40, suppressing molding defects in the propeller fan.

[0046] Furthermore, according to this embodiment, in the propeller fan 20, the protrusion 32 is positioned at the location where stress from the blades 40 is applied. As a result, the mechanical strength of the hub 30 is reinforced by the protrusion 32, and the propeller fan 20 has high strength against stress. For example, the stress that the hub 30 receives from the blades 40 increases as it moves rearward from the peripheral wall 311 in the rotation direction 20R. In the propeller fan 20, the protrusion 32 is positioned between the hub 30 and the blades 40, and the protrusion 32 is positioned behind the peripheral wall 311 in the rotation direction 20R. As a result, the propeller fan 20 has high strength against stress.

[0047] Furthermore, according to this embodiment, the line of the root portion 41 of the blade 40 from the front end 411 to the rear end 412 is curved. As a result, the inclined surface 321s of the inclined portion 321 becomes a smooth curved surface. In addition, the inclined surface 321s of the inclined portion 321 is formed continuously from the circumferential surface 311s of the peripheral wall 311. As a result, the air resistance experienced by the hub 30 is reduced when the propeller fan 20 rotates.

[0048] Furthermore, according to this embodiment, a hot runner mold is used instead of a cold runner mold. This eliminates the need to remove the material from the runner portion and the runner itself. As a result, cost increases are suppressed. Although the gate diameter of a hot runner mold is larger than that of a cold runner mold, by positioning the gate 51 to correspond to the protrusion 32 as in this embodiment, the outer diameter of the hub 30 can be reduced while preventing interference between the gates.

[0049] Although embodiments of the present invention have been described above, it goes without saying that the present invention is not limited to the embodiments described above and can be modified in various ways. Each embodiment is not necessarily an independent form and can be combined as much as technically possible. [Explanation of Symbols]

[0050] 10...Outdoor unit 20…Propeller fan 20c…Central axis 20N…Radial direction 20R…Direction of rotation 30... Hub 30s…outer surface 31...Base 311...peripheral wall 311s…Surrounding surface 3111...front end 312... Insertion hole 313…Center 314a~314f... Ribs 315...Base end wall 32...Protruding part 321…Slope part 321s…Slope surface 3212…rear end 322…Wall part 322s... Wall 301, 323…boundary 324... Corner 325…Protrusion end wall 33…Rear end wall 34...Gate remains 40...feathers 41... Base 411...Front end 412...Rear end 42…Outer edge 43…Lead edge 44… Trailing edge 5…Hot runner mold 5u…Upper mold 5d…Lower mold 51...Gate 101... Cabinet 101u... Top plate 101d…Bottom plate 101w…side plate 101g... Fan guard

Claims

1. A propeller fan comprising a hub and a plurality of blades provided on the hub, The hub has a plurality of protrusions that are formed continuously from the peripheral wall of the hub and that project outward from the peripheral wall in the radial direction of the hub. Propeller fan.

2. In the propeller fan described in claim 1, Each of the aforementioned multiple protrusions has a gate mark. Propeller fan.

3. In the propeller fan described in claim 2, The number of the multiple protrusions and the number of the multiple wings are the same. Each of the aforementioned multiple protrusions is connected to the peripheral wall, Each of the plurality of blades is formed continuously from the protrusion corresponding to each of the plurality of blades. Propeller fan.

4. In the propeller fan described in claim 3, Each of the multiple blades has a front end and a rear end at the base of the hub, in the direction of rotation of the propeller fan. When the propeller fan is viewed from the front, each of the multiple protrusions is formed from the front end to the rear end in the direction of rotation. Propeller fan.

5. In the propeller fan described in claim 1, Any of the aforementioned multiple protrusions is positioned to correspond to the point where the stress on the hub is greatest as the blade rotates. Propeller fan.

6. In the propeller fan described in claim 1, Each of the aforementioned multiple protrusions is, Each of the plurality of blades has an inclined portion on which the base portion at the hub is provided, A wall portion formed from the inclined portion to the peripheral wall It has, When the propeller fan is viewed from the front, the wall portion and the rear ends of each of the multiple blades in the direction of rotation of the propeller fan are formed in a continuous manner. Propeller fan.

7. In the propeller fan described in claim 6, The base portion of any of the multiple protrusions of any of the multiple blades has a front end and a rear end in the direction of rotation of the propeller fan. When the propeller fan is viewed from the front, the inclined portion is formed such that it moves away from the central axis of the propeller fan as it moves from the front end to the rear end. Propeller fan.

8. In the propeller fan described in claim 4, When the propeller fan is viewed from the front, the line of the base portion from the front end to the rear end is curved. Propeller fan.

9. A method for manufacturing a propeller fan comprising a hub and a plurality of blades provided on the hub, The hub is formed continuously from the peripheral wall of the hub and has a plurality of protrusions that extend outward from the peripheral wall in the radial direction of the hub, and the propeller fan having the hub is molded using a hot runner mold. A method for manufacturing a propeller fan.

10. In the method for manufacturing a propeller fan as described in claim 9, Each of the aforementioned multiple protrusions is provided with a gate from which resin material is injected. A method for manufacturing a propeller fan.

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