JP2025171984A - impeller - Google Patents

Abstract

To provide an impeller having high rigidity and excellent lightness.SOLUTION: An impeller 1 includes: a hub portion 3 having a cylindrical shape; and a plurality of blade portions 5 connected to the outer peripheral surface 3o of the hub portion 3. The hub portion 3 includes: a cylindrical portion 11 including the outer peripheral surface 3o and an inner peripheral surface 11i; a boss portion 13 for insertion of an output shaft of an electric motor, the boss portion having a cylindrical shape and being disposed at the center of the cylindrical portion 11; and a connecting portion 15 having a corrugated-plate shape and connecting the inner peripheral surface 11i of the cylindrical portion 11 and an outer peripheral surface 13o of the boss portion 13.SELECTED DRAWING: Figure 2

Description

An embodiment of the present invention relates to an impeller.

Fans for the outdoor and indoor units of air conditioners are known. The fan comprises a resin hub, multiple resin blades connected to the hub, and a counterweight. The part of the hub to which the multiple blades are connected is called the tubular portion. The fan's hub and multiple blades form what is known as an impeller. The fan is also called a blower.

Japanese Patent Application Laid-Open No. 2021-32137

Generally, when a blower is in operation, centrifugal loads tend to cause stress concentrations in the impeller of the blower at the connection points between the tubular portion and the blades. Excessive stress concentrations can damage the impeller. Therefore, to increase the rigidity of the hub and mitigate stress concentrations that occur at the connection points between the tubular portion and the blades, conventional impellers have ribs as reinforcing members. The ribs are attached to the hub so that they are fixed to the bottom and tubular portion of the hub, and extend radially from the boss portion, which is the portion of the hub where the fan motor's rotating shaft is inserted, to the tubular portion.

However, the weight of conventional impellers increases when ribs are provided. Therefore, it is extremely difficult to achieve both high rigidity and excellent lightness in an impeller.

The present invention aims to provide an impeller that is highly rigid yet lightweight.

In order to solve the above problem, an impeller according to an embodiment of the present invention comprises a cylindrical hub portion and a plurality of blades connected to the outer peripheral surface of the hub portion. The hub portion comprises a cylindrical portion having the outer peripheral surface and an inner peripheral surface, a cylindrical boss portion disposed at the center of the cylindrical portion for inserting the output shaft of an electric motor, and a corrugated connecting portion connecting the inner peripheral surface of the cylindrical portion to the outer peripheral surface of the boss portion.

FIG. 2 is a perspective view showing the impeller according to the embodiment of the present invention from the outlet side. FIG. 2 is a side view showing a hub portion of the impeller according to the embodiment of the present invention. 1A is a side view showing a connection portion of an impeller according to an embodiment of the present invention; FIG. 1B is a schematic view showing a 360° development of a cylindrical portion side edge portion of a connection portion of an impeller according to an embodiment of the present invention; FIG. 4 is a diagram showing evaluation locations for stresses occurring in a hub portion of an impeller according to an embodiment of the present invention. FIG. 4 is a diagram showing the positional relationship between a connection portion and a blade portion of an impeller according to an embodiment of the present invention. (A) A schematic diagram showing the positional relationship between the tubular side edge of the connection portion and the first and second notches provided on the tubular portion in the hub portion of a second example of an impeller according to an embodiment of the present invention; (B) A schematic diagram showing the positional relationship between the first and second notches and the inner peripheral edge of the blade portion in the hub portion of a second example of an impeller according to an embodiment of the present invention. 7A is a side view of an impeller according to an embodiment of the present invention, the impeller having a second example of a hub portion; FIG. 7B is an enlarged view of an area S1 surrounded by a dashed double-dashed line rectangle in FIG. 7A; FIG. 7B is a side view of a plurality of second example hub portions in a state where a plurality of impellers shown in FIG. 7A are stacked. 10 is a plan view showing the vicinity of a hub portion of a third example of an impeller according to an embodiment of the present invention, viewed from the outlet side; 1 is a perspective view of an impeller according to an embodiment of the present invention, the impeller having blades with convex portions, viewed from the outlet side; 11 is a perspective view showing a state in which a plurality of impellers shown in FIG. 10 are stacked, as viewed from the outlet side. FIG. FIG. 12 is a side view showing the vicinity of the protrusion in FIG. 11 . FIG. 10 is a perspective view of an impeller according to an embodiment of the present invention, the impeller having a hub portion of a fourth example, viewed from the suction side. 14A is an enlarged view of an area S2 enclosed by a two-dot chain line rectangle in FIG. 13, and FIG. 14B is an enlarged view of an area S3 enclosed by a two-dot chain line rectangle in FIG. 13. 9 is an enlarged vertical cross-sectional view of two vertically adjacent cylindrical portions in an area S4 surrounded by a two-dot chain line rectangle shown in FIG. 8 .

An embodiment of an impeller according to the present invention will be described with reference to Figures 1 to 15. Note that the same or corresponding components are designated by the same reference numerals throughout the drawings.

Figure 1 is a perspective view of an impeller according to an embodiment of the present invention, viewed from the outlet side.

As shown in FIG. 1, the impeller 1 according to this embodiment is a so-called axial flow impeller. The impeller 1 is also simply called a propeller. The impeller 1 is attached to a rotating shaft (not shown), which is the output shaft of an electric motor (not shown) that drives the impeller 1 to rotate, and rotates in a rotational direction R about the rotational center line C of the impeller 1, thereby moving a fluid, primarily air, in a flow direction F. The impeller 1 is used, for example, in an outdoor fan (blower) of an outdoor unit of an air conditioner, and is used to blow air toward the outdoor heat exchanger of the outdoor unit.

When the impeller 1 is rotated in the opposite direction to the rotation direction R, the fluid flows in the opposite direction to the flow direction F. Furthermore, hereafter, unless otherwise specified, the terms "rotation direction," "front side of the rotation direction," "rear side of the rotation direction," "suction side," and "blowout side" each refer to the case where the impeller 1 is rotated in the rotation direction R. Furthermore, the term "suction side" refers to the side of the impeller 1 where the fluid is sucked into the impeller 1. The term "blowout side" refers to the side of the impeller 1 where the fluid is blown out from the impeller 1. Furthermore, the term "rotational axis direction" refers to the direction along the rotational center line C of the impeller 1. The term "radial direction" refers to the direction perpendicular to the rotational axis direction and the rotational direction.

The impeller 1 according to this embodiment includes a hub portion 3 disposed on the rotational centerline C and a plurality of blade portions 5 connected to the outer peripheral surface 3o of the hub portion 3. The impeller 1 is integrally molded, for example, from resin. The integral molding of the impeller 1 is typically performed by injection molding.

The hub portion 3 has a cylindrical shape extending in the direction of the rotational axis of the impeller 1. The hub portion 3 comprises a tubular portion 11 having an outer peripheral surface 3o and an inner peripheral surface 11i of the hub portion 3, a boss portion 13 having a cylindrical shape and positioned in the center of the tubular portion 11 for inserting the rotating shaft of the electric motor, and a connecting portion 15 connecting the inner peripheral surface 11i of the tubular portion 11 and the outer peripheral surface 13o of the boss portion 13. The outer peripheral surface 3o of the hub portion 3 is also the outer peripheral surface of the tubular portion 11.

The tubular portion 11 extends in the direction of the rotational axis of the impeller 1; that is, it has an inlet-side end face 11s located on the inlet side and an outlet-side end face 11b located on the outlet side, and is a component extending from the inlet-side end face 11s to the outlet-side end face 11b. The external shape of the tubular portion 11 is, for example, approximately circular or an approximately polygonal shape having a shape of approximately triangle or greater in plan view. In other words, the external shape of the hub portion 3 is, for example, approximately circular or an approximately polygonal shape having a shape of approximately triangle or greater in plan view.

The boss portion 13 extends in the direction of the rotational axis of the impeller 1; that is, it has an inlet-side end face 13s located on the inlet side and an outlet-side end face 13b located on the outlet side, and is a component extending from the inlet-side end face 13s to the outlet-side end face 13b. The boss portion 13 is disposed on the rotational center line of the hub portion 3, i.e., on the rotational center line C of the impeller 1. The output shaft of the electric motor is fixed to the boss portion 13. In other words, the impeller 1 is connected to the electric motor via the boss portion 13 fixed to the output shaft. The shape of the boss portion 13 is approximately circular in plan view.

The multiple blades 5 protrude radially from the outer peripheral surface 3o of the hub portion 3, i.e., from the cylindrical portion 11. The multiple blades 5 are arranged at equal intervals in the circumferential direction along the outer peripheral surface 3o of the hub portion 3, i.e., in the rotational direction R of the impeller 1. The number of blades 5 can be changed as appropriate. In the example shown in Figure 1, there are four blades 5. The four blades 5 are arranged at 90° intervals in the circumferential direction of the hub portion 3. Each blade 5 is arranged at an angle to the outer peripheral surface 3o of the hub portion 3.

The wing portion 5 is formed in a plate shape and has an inner peripheral edge portion 21, an outer peripheral edge portion 23, a leading edge portion 25, and a trailing edge portion 27.

The inner peripheral edge 21 is the end of the blade 5 on the radially inner side of the impeller 1, and is connected to the outer peripheral surface 3o of the hub portion 3. In other words, the inner peripheral edge 21 is the base of the blade 5 relative to the outer peripheral surface 3o. The inner peripheral edge 21 is inclined toward the outlet side, from the front inner peripheral edge 21a, which is on the front side in the direction of rotation, to the rear inner peripheral edge 21b, which is on the rear side in the direction of rotation.

The outer peripheral edge 23 is the end of the blade portion 5 on the radially outer side of the impeller 1. The outer peripheral edge 23 is inclined toward the outlet side, from the front outer peripheral edge 23a, which is on the front side in the direction of rotation, to the rear outer peripheral edge 23b, which is on the rear side in the direction of rotation. The circumferential length of the outer peripheral edge 23 is greater than the circumferential length of the inner peripheral edge 21.

The leading edge 25 is the end portion of the blade 5 at the front in the direction of rotation. The leading edge 25 is the portion that leads the flow of air in the direction of rotation R of the impeller 1. The leading edge 25 connects the front inner peripheral edge 21a and the front outer peripheral edge 23a.

The trailing edge 27 is the end portion on the rear side in the direction of rotation of the wing section 5. The trailing edge 27 connects the rear inner peripheral edge 21b and the rear outer peripheral edge 23b.

Furthermore, the front inner peripheral edge 21a of each blade 5 is located near the suction side end face 11s of the tubular portion 11. Alternatively, the front inner peripheral edge 21a of each blade 5 may be located so as to be continuous with the suction side end face 11s of the tubular portion 11. Furthermore, the rear inner peripheral edge 21b of each blade 5 is located so as to be continuous with the blow-out side end face 11b of the tubular portion 11. Furthermore, the rear inner peripheral edge 21b of each blade 5 may be located so as to be continuous with the blow-out side end face 11b.

Next, we will explain in detail the connection portion 15 of the hub portion 3.

Figure 2 is a side view showing the hub portion of an impeller according to an embodiment of the present invention.

Note that Figure 2 shows the hub portion 3 of the impeller 1 equipped with four blade portions 5. Furthermore, for ease of explanation, the front half of the cylindrical portion 11 of the hub portion 3 is not shown.

Figure 3(A) is a side view showing the connection portion of an impeller according to an embodiment of the present invention. Figure 3(B) is a schematic diagram showing the cylindrical portion side edge of the connection portion of an impeller according to an embodiment of the present invention unfolded 360 degrees.

Note that Figure 3(A) is a view in which the hub portion 3 and the cylindrical portion 11 are omitted. Figure 3(B) is a view in which the cylindrical portion side edge 31 of the connection portion 15, which is provided along the inner peripheral surface 11i of the cylindrical portion 11, is unfolded 360 degrees from the position indicated by arrow P in Figure 3(A). Figures 3(A) and 3(B) show the connection portion 15 of an impeller 1 equipped with three blade portions 5.

However, if the connecting portion 15 of the hub portion 3 were simply flat, the impeller 1 might not have sufficient rigidity. In that case, stress concentration could occur at the connection between the tubular portion 11 and the blade portion 5 of the impeller 1 while a blower equipped with the impeller 1 is in operation, potentially resulting in damage. On the other hand, if multiple ribs were provided on the flat connecting portion 15, extending radially from the outer circumferential surface 13o of the boss portion 13 to the inner circumferential surface 11i of the tubular portion 11 in the direction of the rotation axis to reduce stress concentration, the weight of the impeller 1 would increase due to the provision of multiple ribs, compromising its lightweight design. Hereinafter, an impeller in which the connecting portion connecting the tubular portion and the boss portion is flat and multiple ribs are provided on the flat connecting portion may be referred to as an "impeller with a conventional structure."

As shown in Figures 2, 3(A), and 3(B) in addition to Figure 1, in the impeller 1 according to this embodiment, the connection portion 15 of the hub portion 3 has a corrugated plate shape.

Specifically, the corrugated connecting portion 15 has a tube-side edge 31 that is provided along the inner peripheral surface 11i of the tube portion 11, and a boss-side edge 33 that is provided along the outer peripheral surface 13o of the boss portion 13. The connecting portion 15 is connected to the inner peripheral surface 11i of the tube portion 11 via the tube-side edge 31, and is connected to the outer peripheral surface 13o of the boss portion 13 via the boss-side edge 33. The tube-side edge 31 has a blow-out side edge 31b located on the blow-out side and a suction-side edge 31s located on the suction side.

Furthermore, the corrugated connecting portion 15 has a plurality of outlet-side peaks 35 that extend radially from the outer peripheral surface 13o of the boss portion 13 to the inner peripheral surface 11i of the tubular portion 11 and are convex on the outlet side, a plurality of suction-side peaks 37 that extend radially from the outer peripheral surface 13o of the boss portion 13 to the inner peripheral surface 11i of the tubular portion 11 and are convex on the suction side, and a plurality of connecting portions 39 that each connect adjacent outlet-side peaks 35 and suction-side peaks 37. In other words, the corrugated connecting portion 15 undulates in the circumferential direction of the hub portion 3 between the tubular portion 11 and the boss portion 13.

Each blow-side apex 35 is inclined toward the blow-out side from the outer peripheral surface 13o of the boss portion 13 toward the inner peripheral surface 11i of the tubular portion 11. In the example shown in Figure 2, the outermost edge 35a of each blow-out side apex 35 is located closer to the suction side than the blow-out side end face 11b of the tubular portion 11. This is not a limitation, and the outermost edge 35a may be located so as to be continuous with the blow-out side end face 11b. The outermost edge 35a is included in the tubular portion side edge 31 of the connection portion 15 and is the part of the blow-out side apex 35 that is radially farthest from the boss portion 13.

Each suction-side apex 37 is inclined toward the suction side from the outer peripheral surface 13o of the boss portion 13 toward the inner peripheral surface 11i of the tubular portion 11. In the example shown in Figure 2, the outermost edge 37a of each suction-side apex 37 is located closer to the outlet side than the suction-side end face 11s of the tubular portion 11. This is not a limitation, and the outermost edge 37a may be located so as to be continuous with the suction-side end face 11s. The outermost edge 37a is included in the tubular portion-side edge 31 of the connecting portion 15 and is the portion of the suction-side apex 37 that is radially farthest from the boss portion 13.

The number of blow-out side peaks 35 is equal to the number of suction-side peaks 37. Furthermore, the number of blow-out side peaks 35 and the number of suction-side peaks 37 is equal to the number of blades 5.

The multiple connecting portions 39 are inclined toward the suction side or the blowing side. The multiple connecting portions 39 are inclined and connected to the inner circumferential surface 11i of the tubular portion 11 via the tubular portion side edge 31, and are inclined and connected to the outer circumferential surface 13o of the boss portion 13 via the boss portion side edge 33.

Figure 4 shows the evaluation locations for stresses occurring in the hub portion of an impeller according to an embodiment of the present invention. Note that Figure 4 is a plan view of the impeller 1 from the outlet side.

In the process of discovering the corrugated connecting portion 15 described above, the inventors conducted the following analysis of the rigidity and light weight of the impeller 1, and compared it with impellers of conventional structure.

As an example of analysis, the centrifugal load (stress) generated in the hub portion 3 from positions M1 to M3 shown in Figure 4 when an impeller 1 equipped with three blade portions 5 is rotated in the rotational direction R was calculated. In the example of Figure 4, positions M1 to M3 are arranged at equal intervals of 30° along the circumferential direction of the hub portion 3. Positions M1 to M3 are at or near the connection points between the tubular portion 11 and the blade portions 5, and are locations where stress concentration is likely to occur when the impeller 1 is rotated.

As a result of the analysis, if the stress generated at positions M1 to M3 of the hub portion of an impeller with a conventional structure and three similar blade portions is set at 100%, the stress generated at positions M1 to M3 was 70% or less. In other words, it was confirmed that the corrugated connecting portion 15 at the connection point between the cylindrical portion 11 and the blade portion 5 improves the rigidity of the hub portion 3, reducing the generated stress by 30% or more compared to the hub portion of an impeller with a conventional structure.

As another example of analysis, the centrifugal load (stress) generated across the entire hub portion 3 was calculated when an impeller 1 equipped with three blade portions 5 shown in Figure 4 was rotated in the rotation direction R. Furthermore, the mass of only the hub portion 3 was calculated.

As a result of the analysis, if the stress generated across the entire hub section of an impeller with a conventional structure, which also has three blade sections, is taken as 100%, then the stress generated across the entire hub section 3 was 67.8%. Furthermore, if the mass of the hub section of an impeller with a conventional structure is taken as 100%, then the mass of hub section 3 was 82.2%. In other words, it was confirmed that the corrugated connecting section 15 improves the overall rigidity and lightness of the hub section 3, reducing the generated stress by more than 30% and the mass by more than 17% compared to the hub section of an impeller with a conventional structure.

As yet another example of analysis, the centrifugal load (stress) generated across the entire hub portion 3 was calculated when an impeller 1 having four blade portions 5 shown in Figure 1 was rotated in the rotation direction R. Furthermore, the mass of the hub portion 3 alone was calculated.

As a result of the analysis, if the stress generated across the entire hub section of an impeller with a conventional structure, which also has four blades, is taken as 100%, the stress generated across the entire hub section 3 is 87.2%. Furthermore, if the mass of the hub section of an impeller with a conventional structure is taken as 100%, the mass of hub section 3 is 67.7%. In other words, it was confirmed that the corrugated connecting section 15 improves the overall rigidity and lightness of the hub section 3, reducing the generated stress by more than 12% and the mass by more than 30% compared to the hub section of an impeller with a conventional structure.

The inventors have discovered that an impeller 1 having a corrugated connecting portion 15 increases rigidity and reduces generated stress while also improving lightness.

The hub portion 3 may have multiple ribs on the connection portion 15, as long as the lightweight nature of the hub portion 3 is not compromised. The multiple ribs are formed radially from the outer peripheral surface 13o of the boss portion 13 to the inner peripheral surface 11i of the tubular portion 11, extending in the direction of the rotation axis.

Figure 5 shows the positional relationship between the connection portion and blade portion of an impeller according to an embodiment of the present invention.

Note that Figure 5 shows the connection portion 15 when the number of wing portions 5 is three. The boss portion 13 and connection portion 15 visible inside the hub portion 3 are shown with dotted lines, and the inner peripheral edge portion 21 of the wing portion 5 provided on the outer peripheral surface 3o of the hub portion 3, i.e., the outer peripheral surface 3o of the tubular portion 11, is shown with a two-dot chain line.

Generally, when an impeller is cooled after injection molding, shrinkage of the molten resin material can cause sink marks to form on the inner surface of the cylindrical portion facing the inner peripheral edge of the blade portion. These sink marks reduce the rigidity of the connection between the cylindrical portion and the blade portion, causing stress concentrations.

Therefore, as shown in FIG. 5 , the tube-side edge 31 of the connection portion 15 may be provided so as to generally follow the inner peripheral edge 21 of the blade portion 5, with the tube portion 11 sandwiched between the tube-side edge 31 and the inner peripheral edge 21. This allows the tube-side edge 31 of the connection portion 15 to be provided over most of the inner peripheral surface 11i of the tube portion 11 that faces the inner peripheral edge 21 of the blade portion 5. Therefore, during cooling after injection molding of the impeller 1, the tube-side edge 31 of the connection portion 15 and the inner peripheral edge 21 of the blade portion 5 shrink evenly with the tube portion 11 sandwiched between them, thereby suppressing the occurrence of sink marks. Furthermore, by configuring the impeller 1 in this manner, it is possible to cut the portions of the hub portion 3 where the tube-side edge 31 and inner peripheral edge 21 are not provided in the impeller 1 of this embodiment. As a result, the hub portion 3 can be made even lighter without excessively reducing the rigidity of the impeller 1.

Figure 6(A) is a schematic diagram showing the positional relationship between the cylindrical edge of the connection portion and the first and second notches provided on the cylindrical portion in a hub portion of a second example of an impeller according to an embodiment of the present invention, and Figure 6(B) is a schematic diagram showing the positional relationship between the first and second notches and the inner peripheral edge of the blade portion in a hub portion of a second example of an impeller according to an embodiment of the present invention.

Note that duplicated descriptions will be omitted for the hub portion 3 of the first example, as well as the hub portion 3A of the second example, the hub portion 3B of the third example, and the hub portion 3C of the fourth example described below. The hub portion 3A of the second example may be referred to simply as the hub portion 3A below. Figures 6(A) and 6(B) are schematic views of the outer peripheral surface 3o of the hub portion 3A, unfolded 360 degrees from the reference line Q. In Figures 6(A) and 6(B), the cylindrical portion-side edge 31 of the connection portion 15, which is provided on the inner peripheral surface 11i of the cylindrical portion 11 facing the outer peripheral surface 3o of the hub portion 3A, is shown by a dotted line. Furthermore, Figure 6(B) shows the inner peripheral edge 21 of the wing portion 5, which is provided on the outer peripheral surface 3o of the hub portion 3A, by a two-dot chain line.

Figure 7(A) is a side view of an impeller according to an embodiment of the present invention, which is an impeller equipped with a second example hub portion, and Figure 7(B) is an enlarged view of the area S1 enclosed by the dashed-dotted rectangle in Figure 7(A).

As shown in FIG. 6(A), the tubular portion 11 of the hub portion 3A may be arranged to generally follow a first imaginary line VL1, which is formed by offsetting the outlet-side edge 31b of the tubular portion-side edge 31 of the connecting portion 15 toward the outlet side, and a second imaginary line VL2, which is formed by offsetting the suction-side edge 31s of the tubular portion-side edge 31 of the connecting portion 15 toward the suction side. In other words, the tubular portion 11 of the hub portion 3A may have a plurality of first notches 41 extending from the outlet-side end face 11b of the tubular portion 11 to generally follow the first imaginary line VL1, and a plurality of second notches 43 extending from the suction-side end face 11s of the tubular portion 11 to generally follow the second imaginary line VL2. In other words, the tubular portion 11 may be cut to generally follow the first imaginary line VL1 and the second imaginary line VL2, and a plurality of first notches 41 and a plurality of second notches 43 may be provided in the tubular portion 11. In addition to Figure 6(A), as shown in Figure 7(a), the outlet-side end surface 11b and the suction-side end surface 11s of the tubular portion 11 each have a wavy shape. In other words, the side shape of the tubular portion 11, i.e., the shape of the outer peripheral surface 3o, is wavy.

Each of the first notches 41 has a first inclined portion 41a that slopes from the suction side toward the suction side, and each of the second notches 43 has a second inclined portion 43a that slopes from the suction side toward the blowing side. The first inclined portion 41a is also part of the corrugated blowing-side end face 11b, and the second inclined portion 43a is also part of the corrugated suction-side end face 11s. In other words, the corrugated blowing-side end face 11b has multiple first inclined portions 41a, and the corrugated suction-side end face 11s has multiple second inclined portions 43a. Furthermore, the first notches 41 do not necessarily need to be positioned completely along the first imaginary line VL1. Similarly, the second notches 43 do not necessarily need to be positioned completely along the second imaginary line VL2. In the example of Figure 6(A), the shapes of the first notches 41 and the second notches 43 are approximately trapezoidal when viewed from the radially outside of the hub portion 3A. The first notches 41 and second notches 43 are arranged alternately in the circumferential direction of the hub portion 3A, i.e., in the circumferential direction of the cylindrical portion 11.

Furthermore, as shown in FIG. 6(B), the first notch 41 and the second notch 43 correspond to portions of the tubular portion 11 that are not provided with either the tubular portion side edge 31 or the inner peripheral edge 21. In other words, the tubular portion 11 has multiple first notch 41 and multiple second notch 43 that avoid the tubular portion side edge 31 and the inner peripheral edge 21. The multiple first notch 41 and multiple second notch 43 provided in the tubular portion 11 in this manner do not impair the rigidity required for the impeller 1. Therefore, the multiple first notch 41 and multiple second notch 43 improve the lightness of the hub portion 3A and, ultimately, the impeller 1.

Figure 8 is a side view of the hub portion of multiple second examples of impellers stacked one on top of the other, as shown in Figure 7(A).

Furthermore, as shown in FIG. 8, the tubular portion 11 has multiple first notches 41 and multiple second notches 43, so that when multiple impellers 1 are stacked in the direction of the rotation axis, the suction side end face 11s of the tubular portion 11 of the upper impeller 1 fits with the outlet side end face 11b of the tubular portion 11 of the lower impeller 1, suppressing misalignment in the direction of rotation. Therefore, when multiple impellers 1 are stacked during transportation, the cargo is less likely to collapse. Furthermore, when multiple impellers 1 are stacked, the stack height is reduced because the suction side end face 11s of the tubular portion 11 of the upper impeller 1 fits with the outlet side end face 11b of the tubular portion 11 of the lower impeller 1. As an example, if the height of five stacked impellers that do not have multiple first notches 41 and multiple second notches 43 is taken as 100%, the height of seven stacked impellers 1 that have multiple first notches 41 and multiple second notches 43 is 98.4%. In other words, the impellers 1 exhibit excellent space-saving properties when stacked. Therefore, impellers 1 that have multiple first notches 41 and multiple second notches 43 can improve space-saving properties when multiple impellers 1 are stacked, making it possible to significantly reduce transportation and storage costs.

Figure 9 is a plan view showing the vicinity of the hub portion of a third example of an impeller according to an embodiment of the present invention, viewed from the outlet side. Note that the hub portion 3B of the third example may hereinafter be simply referred to as the hub portion 3B.

As shown in Figure 9, the connection portion 15 of the hub portion 3B may have multiple drain holes 45.

Specifically, the drain hole 45 is generally rectangular (trapezoidal) in shape, with the opening width increasing from the center of the hub portion 3B toward the outer periphery. The drain hole 45 is symmetrical with respect to an imaginary line extending radially of the hub portion 3B.

In order to balance the impeller 1 during rotation, it is generally preferable that the number of drain holes 45 match the number of blades 5. In the example of Figure 9, there are three blades 5 and three drain holes 45. The three drain holes 45 are arranged at equal intervals of 120° in the connecting portion 15 along the circumferential direction of the hub portion 3B. For example, if there are four blades 5, there will be four drain holes 45. The four drain holes 45 are arranged at equal intervals of 90° in the connecting portion 15 along the circumferential direction of the hub portion 3B.

With multiple drainage holes 45 configured in this manner, when the impeller 1 is used as an outdoor fan in an outdoor unit of an air conditioner, rainwater, melted snow, and other moisture that accumulates in the hub portion 3B can be properly drained. Furthermore, by providing multiple drainage holes 45, the hub portion 3B can be made even lighter.

Furthermore, each drainage hole 45 may be provided between the inner peripheral edges 21 of adjacent blade sections 5 in the rotation direction R of the impeller 1. This maintains the rigidity of the hub section 3B without reducing it. In other words, the hub section 3B improves drainage and lightness without reducing its rigidity. Furthermore, because the multiple drainage holes 45 are provided in the inclined connecting section 39, moisture that accumulates in the hub section 3B due to gravity is easily drained as it flows down the inclined connecting section 39. Furthermore, because the multiple drainage holes 45 are provided near the outer periphery of the hub section 3B, moisture that accumulates in the hub section 3B is easily drained as it flows outward due to the centrifugal force of the rotating impeller 1.

Figure 10 is a perspective view of an impeller according to an embodiment of the present invention, showing an impeller equipped with blades having convex portions, viewed from the outlet side.

Figure 11 is a perspective view showing multiple impellers of Figure 10 stacked together from the blowing side.

Figure 12 is a side view showing the vicinity of the protrusion in Figure 11.

As shown in Figure 10, the trailing edge portion 27 of each blade portion 5 may have a trailing edge surface 51 that is continuous with the blowing side end surface 11b of the tubular portion 11, and a protrusion 53 that protrudes from the trailing edge surface 51 toward the blowing side so as to follow the outermost edge of the blowing side end surface 11b.

The number of protrusions 53 provided on the impeller 1 matches the number of blades 5. In the example of Figure 10, the impeller 1 has three blades 5. In other words, the impeller 1 has three protrusions 53. Like the three blades 5, the three protrusions 53 are arranged on the outer periphery of the hub portion 3A at 120° intervals in the circumferential direction of the hub portion 3A.

With such multiple protrusions 53, when multiple impellers 1 are stacked in the direction of the rotation axis, as shown in Figures 11 and 12, the protrusions 53 on the lower impeller 1 come into contact with the outer peripheral surface 3o of the hub portion 3A of the upper impeller 1, preventing the upper impeller 1 from shifting radially. Note that the protrusions 53 are relatively small components. Therefore, even if the impeller 1 has multiple protrusions 53, the weight of the impeller 1 does not increase substantially, and the impeller 1 remains lightweight.

Also, as shown again in Figure 7(B), the trailing edge portion 27 of each blade portion 5 may have a trailing edge surface 51A that is continuous with the blowing side end surface 11b of the tubular portion 11 and extends further toward the blowing side than the blowing side end surface 11b.

The trailing edge surface 51 and convex portion 53 indicated by the two-dot chain line in Figure 7(B) are the trailing edge surface 51 and convex portion 53 shown in Figure 10, superimposed on Figure 7(B) for ease of explanation. The trailing edge surface 51A extends further toward the blowing side than the blowing-side end surface 11b, and thus has the same function as the convex portion 53. That is, when multiple impellers 1 are stacked in the rotational axis direction, the trailing edge surface 51A of the lower impeller 1 contacts the outer peripheral surface 3o of the hub portion 3A of the upper impeller 1, preventing the upper impeller 1 from shifting radially. Note that such a trailing edge surface 51A can be designed as an integral part of the blade portion 5.

Figure 13 is a perspective view of an impeller according to an embodiment of the present invention, showing an impeller equipped with a fourth example hub portion, from the suction side. Note that the fourth example hub portion 3C may hereinafter be simply referred to as the hub portion 3C.

Figure 14(A) is an enlarged view of area S2 enclosed by the dashed-dotted line rectangle in Figure 13, and Figure 14(B) is an enlarged view of area S3 enclosed by the dashed-dotted line rectangle in Figure 13.

As shown in Figures 13, 14(A), and 14(B), the tubular portion 11 of the hub portion 3C has multiple claw portions 55 spaced apart on the inner circumferential surface 11i or the outer circumferential surface 3o, and the multiple claw portions 55 may protrude toward the suction side beyond the suction side end face 11s of the tubular portion 11, or may protrude toward the blowing side beyond the blowing side end face 11b of the tubular portion 11.

The claws 55 are arranged circumferentially around the tubular portion 11. The number of claws 55 provided on the impeller 1 depends on the size of the claws 55 and the height to which they protrude toward the outlet or inlet side, but is, for example, two or more. In the example shown in Figure 13, the impeller 1 has two claws 55 that protrude toward the inlet side from the inner circumferential surface 11i of the tubular portion 11. The two claws 55 are arranged at an interval of 120° or 240° in the rotational direction R of the impeller 1.

With such multiple claw portions 55, when multiple impellers 1 are stacked in the direction of the rotation axis, the multiple claw portions 55 catch on the vertically adjacent tubular portions 11, preventing the upper impeller 1 from shifting radially. Even when the impeller 1 is equipped with multiple claw portions 55, the weight of the impeller 1 does not increase substantially, and the impeller 1 remains lightweight.

Furthermore, each claw portion 55 may be provided on the inner peripheral surface 11i of the tubular portion 11 and near the front inner peripheral edge portion 21a of the inner peripheral edge portion 21.

Reinforcing members such as ribs or thickened portions can be installed on the inner peripheral surface 11i of the tubular portion 11, which faces the inner peripheral edge 21 of the blade portion 5 across the tubular portion 11, to firmly secure the blade portion 5 to the tubular portion 11. By extending a portion of these reinforcing members toward the suction side or the blowing side, the claw portions 55 can be easily installed without requiring additional members or excessively increasing the amount of resin material that makes up the impeller 1.

Figure 15 is an enlarged vertical cross-sectional view of two vertically adjacent cylindrical sections in the area S4 enclosed by the dashed-dotted line rectangle shown in Figure 8.

Note that Figure 15 is a cross-sectional view of region S4 cut along a plane that includes the rotation center line C and is parallel to the rotation center line C.

Also, as shown in FIG. 15, at least a portion of the blow-side end face 11b of the tubular portion 11 and at least a portion of the suction-side end face 11s of the tubular portion 11 may be inclined from the outer peripheral surface 3o of the tubular portion 11 to the inner peripheral surface 11i of the tubular portion 11. In other words, at least a portion of the blow-side end face 11b and at least a portion of the suction-side end face 11s may be inclined in the radial direction (thickness direction) of the tubular portion 11. In this case, at least a portion of the blow-side end face 11b is positioned so as to face at least a portion of the suction-side end face 11s in the rotational axis direction.

If at least a portion of the blow-out side end face 11b and at least a portion of the suction-side end face 11s are in this manner, when multiple impellers 1 are stacked in the direction of the rotation axis, at least a portion of the suction-side end face 11s of the upper tubular portion 11 and the blow-out side end face 11b of the lower tubular portion 11 in adjacent tubular portions 11 in the vertical direction will come into contact with each other, preventing the upper impeller 1 from shifting radially.

15, at least a portion of the blow-side end face 11b of the tubular portion 11 includes a plurality of first inclined portions 41a, and at least a portion of the suction-side end face 11s of the tubular portion 11 includes a plurality of second inclined portions 43a. However, this is not a limitation; at least a portion of the blow-side end face 11b may include other portions of the blow-side end face 11b other than the first inclined portions 41a, and at least a portion of the suction-side end face 11s may include other portions of the suction-side end face 11s other than the second inclined portions 43a. Furthermore, at least a portion of the blow-side end face 11b and at least a portion of the suction-side end face 11s may be inclined toward the suction side from the outer peripheral surface 3o of the tubular portion 11 to the inner peripheral surface 11i of the tubular portion 11, or may be inclined toward the blow-side from the outer peripheral surface 3o of the tubular portion 11 to the inner peripheral surface 11i of the tubular portion 11.

As described above, the impeller 1 according to this embodiment includes a corrugated connecting portion 15 that connects the inner peripheral surface 11i of the tubular portion 11 and the outer peripheral surface 13o of the boss portion 13. Therefore, compared to impellers of a conventional structure that include a flat connecting portion with a flat plate shape that connects the inner peripheral surface of the hub portion with the outer peripheral surface of the boss portion, and a rib portion that extends from the flat surface of the connecting portion and connects the inner peripheral surface of the hub portion with the outer peripheral surface of the boss portion, the impeller 1 can reduce the weight of the hub portion 3 while reducing the stress, which is the centrifugal load, that occurs in the hub portion 3 when the impeller 1 is rotated in the rotational direction R. In other words, the impeller 1 can achieve excellent lightness while increasing rigidity.

The impeller 1 according to this embodiment also includes a connecting portion 15 having a tubular portion-side edge 31 that is positioned along the inner peripheral edge 21 of the blade portion 5, sandwiching the tubular portion 11 therebetween. Therefore, when the impeller 1 is cooled after injection molding, the tubular portion-side edge 31 of the connecting portion 15 and the inner peripheral edge 21 of the blade portion 5 shrink evenly, sandwiching the tubular portion 11 therebetween, thereby preventing the occurrence of sink marks. Furthermore, the impeller 1 can be made lighter by removing the portion of the tubular portion 11 where the tubular portion-side edge 31 of the connecting portion 15 and the inner peripheral edge 21, which is the base of the blade portion 5, are not present, without reducing rigidity.

The impeller 1 according to this embodiment also includes a tubular portion 11 having a plurality of first notches 41 that are provided generally along a first imaginary line VL1 that offsets the blow-out side edge 31b of the tubular portion-side edge 31 of the connecting portion 15 toward the blow-out side, and a plurality of second notches 43 that are provided generally along a second imaginary line VL2 that offsets the suction-side edge 31s of the tubular portion-side edge 31 of the connecting portion 15 toward the suction side. In other words, the impeller 1 has a plurality of first notches 41 and a plurality of second notches 43 in the tubular portion 11 that avoid both the tubular portion-side edge 31 of the connecting portion 15 and the inner peripheral edge 21 of the blade portion 5. This allows the impeller 1 to be even lighter without sacrificing rigidity.

The impeller 1 according to this embodiment also includes a connection portion 15 with multiple drainage holes 45. Therefore, when the impeller 1 is used in an outdoor fan for an outdoor unit of an air conditioner, it can properly drain water such as rainwater and melted snow that accumulates in the hub portion 3B. Furthermore, by providing multiple drainage holes 45, the impeller 1 can be made even lighter.

The impeller 1 according to this embodiment also includes multiple blades 5, each of which has a trailing edge surface 51 that is continuous with the blow-side end surface 11b of the tubular portion 11, and a protrusion 53 that protrudes from the trailing edge surface 51 toward the blow-side along the outermost edge of the blow-side end surface 11b. With this type of impeller 1, stacking multiple impellers 1 together can prevent the stack from collapsing.

Furthermore, the impeller 1 according to this embodiment includes multiple blades 5, each of which has a trailing edge surface 51A that is continuous with the blow-side end surface 11b of the tubular portion 11 and extends further toward the blow-out side than the blow-out side end surface 11b. With this type of impeller 1, it is possible to prevent the stack from collapsing when multiple impellers 1 are stacked.

The impeller 1 according to this embodiment also includes a tubular portion 11 having a plurality of claws 55 that are spaced apart on the inner peripheral surface 11i of the tubular portion 11 or the outer peripheral surface 3o of the tubular portion 11 and that protrude toward the suction side beyond the suction side end face 11s of the tubular portion 11, or that protrude toward the blow side beyond the blow side end face 11b of the tubular portion 11. With such an impeller 1, it is possible to prevent the stack from falling over when multiple impellers 1 are stacked.

In addition, in the impeller 1 according to this embodiment, at least a portion of the blow-side end face 11b of the tubular portion 11 and at least a portion of the suction-side end face 11s of the tubular portion 11 are inclined from the outer peripheral surface 3o of the tubular portion 11 to the inner peripheral surface 11i of the tubular portion 11. Furthermore, at least a portion of the blow-side end face 11b is positioned so as to face at least a portion of the suction-side end face 11s in the direction of the rotation axis. With this type of impeller 1, it is possible to prevent the stack from collapsing when multiple impellers 1 are stacked.

Therefore, the impeller 1 according to this embodiment can be made lightweight while maintaining high rigidity.

While several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments may be embodied in a variety of other forms, and various omissions, substitutions, and modifications may be made without departing from the spirit of the invention. These embodiments and their variations are within the scope and spirit of the invention, and are also included in the scope of the invention and its equivalents as set forth in the claims.

1...impeller, 3, 3A, 3B, 3C...hub portion, 3o...outer peripheral surface, 5...blade portion, 11...tubular portion, 11i...inner peripheral surface, 11s, 13s...suction side end surface, 11b, 13b...blow-out side end surface, 13...boss portion, 13o...outer peripheral surface, 15...connection portion, 21...inner peripheral edge portion, 21a...front inner peripheral edge portion, 21b...rear inner peripheral edge portion, 23...outer peripheral edge portion, 23a...front outer peripheral edge portion, 23b...rear outer peripheral edge portion, 25...front edge portion, 27...rear edge portion, 31...tubular portion side edge portion, 31b...blow-out side edge, 31s...suction side edge , 33...boss side edge, 35...blow-out side apex, 35a, 37a...outermost edge, 37...suction side apex, 39...connecting portion, 41...first notch, 41a...first inclined portion, 43...second notch, 43a...second inclined portion, 45...drain hole, 51, 51A...trailing edge surface, 53...convex portion, 55...claw portion, C...rotation center line, F...flow direction, M1, M2, M3...position, P...arrow, Q...reference line, R...rotation direction, S1, S2, S3, S4...area, VL1...first virtual line, VL2...second virtual line.

Claims (8)

a hub portion having a cylindrical shape;
a plurality of wing portions connected to the outer peripheral surface of the hub portion,
The hub portion is
a cylindrical portion having the outer circumferential surface and an inner circumferential surface;
a boss portion having a cylindrical shape and disposed at the center of the cylindrical portion, into which an output shaft of an electric motor is inserted;
a corrugated plate-shaped connecting portion that connects the inner peripheral surface of the cylindrical portion and the outer peripheral surface of the boss portion. the connecting portion has a cylindrical portion-side edge portion that is along the inner circumferential surface of the cylindrical portion,
Each of the wing portions has an inner peripheral edge portion that follows the outer peripheral surface of the cylindrical portion,
The impeller according to claim 1 , wherein the cylindrical portion side edge portion of the connecting portion is provided along the inner peripheral edge portion, with the cylindrical portion sandwiched between the cylindrical portion side edge portion and the inner peripheral edge portion. The cylindrical portion side edge portion of the connection portion is
a blowing side edge located on the blowing side;
a suction side edge located on the suction side; and
a blowing side end surface located on the blowing side;
a suction side end surface located on the suction side;
A plurality of first notches provided generally along a first imaginary line offsetting the blowing side edge toward the blowing side;
a plurality of second notches provided so as to substantially follow a second imaginary line that offsets the suction side edge toward the suction side;
The impeller according to claim 2 , wherein the shape of the outlet end surface and the shape of the suction end surface are each wave-shaped. An impeller as described in claim 1, wherein the connection portion has multiple drain holes. The cylindrical portion has a blowing-side end surface located on the blowing side,
Each of the wing portions has a trailing edge portion located on the rear side in the rotational direction,
The trailing edge portion is
a trailing edge surface continuous with the blowing side end surface;
The impeller according to claim 1 , further comprising: a protrusion that protrudes from the trailing edge surface toward the outlet side along an outermost edge of the outlet-side end surface. The cylindrical portion has a blowing-side end surface located on the blowing side,
Each of the wing portions has a trailing edge portion located on the rear side in the rotational direction,
The impeller according to any one of claims 1 to 4, wherein the trailing edge portion has a trailing edge surface that is continuous with the blowing-side end surface and extends further toward the blowing side than the blowing-side end surface. The cylindrical portion is
a blowing side end surface located on the blowing side;
a suction side end face located on the suction side;
a plurality of claws provided at intervals on the inner circumferential surface of the cylindrical portion or the outer circumferential surface of the cylindrical portion,
The impeller according to claim 1 , wherein the plurality of claws protrude toward the suction side beyond the suction side end face, or protrude toward the blowing side beyond the blowing side end face. The cylindrical portion is
a blowing side end surface located on the blowing side;
a suction side end surface located on the suction side,
At least a portion of the outlet-side end surface and at least a portion of the suction-side end surface are inclined from the outer peripheral surface of the cylindrical portion to the inner peripheral surface of the cylindrical portion,
The impeller according to claim 1 , wherein the at least a portion of the outlet-side end surface is positioned so as to face the at least a portion of the suction-side end surface in the direction of the rotation axis.