Impeller and fan device

Abstract

This impeller in a fan device includes a hub and a plurality of rotor blades. The hub assumes the shape of a bottomed cylinder extending in the axial direction. One end of the hub in the axial direction is open. The plurality of rotor blades are disposed further radially outward than the hub and are arranged along the circumferential direction. Each of the rotor blades has a blade part and a holding part. The blade part expands in the axial direction and the radial direction and inclines in one circumferential direction toward the other side in the axial direction. The holding part extends radially inward from one end of the blade part in the axial direction and is connected to the hub.

Description

Impeller and fan device

[0001] The present invention relates to an impeller and a fan device.

[0002] Conventionally, there is known a blower (fan device) that draws in air in the axial direction and sends it outward in the radial direction. For example, the fan (also called an impeller) of the blower is composed of a disk-shaped hub, a shroud, and multiple blades. A rotating shaft of a motor is fixed to the center of the hub. The center of the hub bulges outward in a bell shape toward the shroud. The shroud is annular and opens toward the suction port, and is disposed opposite the hub. Multiple blades are disposed between the shroud and the hub (see JP 2011-58442 A).

[0003] JP 2011-58442 A

[0004] However, in the fan of JP 2011-58442 A, the hub (particularly the portion of the hub that holds the blades radially outward from the center) is disk-shaped, which creates air resistance due to friction with the air during rotation, making it necessary to ensure sufficient torque for the fan to rotate.

[0005] An object of the present invention is to reduce fluid resistance at a holder that holds blades of an impeller.

[0006] An exemplary impeller of the present invention includes a hub and a plurality of rotor blades. The hub is a closed-ended cylindrical shape extending in the axial direction. One axial end of the hub is open. The plurality of rotor blades are arranged radially outward from the hub and aligned in the circumferential direction. Each of the rotor blades has a blade portion and a retaining portion. The blade portion extends in the axial and radial directions and is inclined in one circumferential direction toward the other axial direction. The retaining portion extends radially inward from one axial end of the blade portion and is connected to the hub.

[0007] An exemplary fan device of the present invention delivers fluid drawn in one axial direction radially outward. The fan device includes an impeller and a motor. The impeller has a hub and a plurality of rotor blades. The hub is a closed-circumferential cylinder extending in the axial direction. One axial end of the hub is open. The rotor blades are arranged radially outward from the hub and aligned circumferentially. At least a portion of the motor is disposed inside the hub. The motor has a shaft. The shaft is rotatable together with the impeller about a rotation axis extending in the axial direction. Each rotor blade has a blade portion and a retaining portion. The blade portion extends axially and radially and is inclined circumferentially toward the other axial direction. The retaining portion extends radially inward from one axial end of the blade portion and is connected to the hub.

[0008] Further features and advantages of the present invention will become more apparent from the following embodiments.

[0009] According to the exemplary impeller and fan device of the present invention, it is possible to reduce the fluid resistance at the holder that holds the blades of the impeller.

[0010] Fig. 1 is a cross-sectional view showing an example of the configuration of a fan device according to an embodiment, Fig. 2 is a plan view showing the interior of the fan device according to an embodiment, and Fig. 3 is a perspective view showing an example of the configuration of an impeller according to an embodiment.

[0011] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0012] In this specification, in the fan unit 100, the direction parallel to the rotation axis J is referred to as the "axial direction Da." Within the axial direction Da, the direction from the first plate portion 31 to the second plate portion 32 (described later) is referred to as the "one axial direction Da1," and the direction from the second plate portion 32 to the first plate portion 31 is referred to as the "other axial direction Da2." Furthermore, the direction perpendicular to the rotation axis J is referred to as the "radial direction." Within the radial direction, the direction approaching the rotation axis J is referred to as the "radial inward direction," and the direction away from the rotation axis J is referred to as the "radial outward direction." Furthermore, the rotation direction centered on the rotation axis J is referred to as the "circumferential direction Dc." Within the circumferential direction Dc, one direction is referred to as the "one circumferential direction Dc1," and the other direction is referred to as the "other circumferential direction Dc2." In this specification, when the fan device 100 and the impeller 1 are viewed from the other axial direction Da2 side toward the one axial direction Da1, the one circumferential direction Dc1 is the counterclockwise direction centered on the rotation axis J in the circumferential direction Dc, and the other circumferential direction Dc2 is the clockwise direction centered on the rotation axis J in the circumferential direction Dc.

[0013] In this specification, the term "annular" refers not only to a shape that is continuous and uninterrupted throughout the entire circumferential direction Dc about the rotation axis J, but also to a shape that has one or more interruptions in a portion of the entire circumferential direction Dc about the rotation axis J. It also refers to a shape that describes a closed curve on a curved surface that is centered on the rotation axis J and intersects with the rotation axis J.

[0014] Furthermore, in the positional relationship between any one of a direction, a line, and a plane and any other, "parallel" includes not only a state in which the two do not intersect at all no matter how far they are extended, but also a state in which they are substantially parallel. Furthermore, "perpendicular" and "orthogonal" each include not only a state in which the two intersect at 90 degrees, but also a state in which they are substantially perpendicular and a state in which they are substantially orthogonal. In other words, "parallel," "perpendicular," and "orthogonal" each include a state in which there is an angular deviation in the positional relationship between the two to an extent that does not deviate from the spirit of the present invention.

[0015] It should be noted that these are used merely for the purpose of explanation and are not intended to limit the actual positional relationship, direction, names, etc.

[0016] 1. Embodiment Fig. 1 is a cross-sectional view showing an example of the configuration of a fan device 100 according to an embodiment. Fig. 2 is a plan view showing the interior of the fan device 100 according to an embodiment. Note that Fig. 1 shows the cross-sectional structure when the fan device 100 is cut along a plane including the two-dot chain line I and the rotation axis J in Fig. 2. Also, in Fig. 2, the first plate portion 31 is not shown to make the interior easier to see.

[0017] <1-1. Fan device 100> The fan device 100 is a so-called centrifugal fan that draws in fluid F in one axial direction Da1 and sends it outward in the radial direction. In this embodiment, the fluid F drawn in and sent out by the fan device 100 is air. However, this is not intended to be limiting, and the fluid F may be a gas other than air, or a liquid. The fan device 100 is used, for example, as a cooling fan for electronic devices that require thinness. However, the use of the fan device 100 is not limited to this example.

[0018] The fan device 100 includes an impeller 1 , a motor 2 , a housing 3 , and a substrate 4 .

[0019] The impeller 1 is rotatable about a rotation axis J extending in the axial direction Da. The impeller 1 is attached to a motor 2. The impeller 1 has a covered cylindrical hub 11 and a plurality of rotor blades 12. In this specification, a shape in which one end of a cylindrical body (for example, a cylindrical portion 112 described later) is covered with a lid-shaped body (for example, a plate portion 111 described later) is referred to as a "covered cylindrical shape."

[0020] The motor 2 is a drive source that rotates the impeller 1. At least a portion of the motor 2 is disposed inside the hub 11. The motor 2 has a shaft 21 that extends in the axial direction Da along the rotation axis J. The shaft 21 is rotatable together with the impeller 1 around the rotation axis J that extends in the axial direction Da. More specifically, the impeller 1 is coupled to the other axial end of the shaft 21. The motor 2 rotates the shaft 21 around the rotation axis J, thereby rotating the impeller 1 together with the shaft 21.

[0021] The housing 3 accommodates the impeller 1, the motor 2, and the substrate 4. The housing 3 has a first plate portion 31, a second plate portion 32, and a peripheral wall portion 33.

[0022] The first plate portion 31 is disposed on one side in the axial direction Da1 of the impeller 1 and extends in a direction intersecting the axial direction Da. The motor 2 and the circuit board 4 are fixed to the inner surface (the other end surface in the axial direction) of the first plate portion 31.

[0023] The second plate portion 32 is positioned on the other axial direction Da2 than the impeller 1 and extends in a direction intersecting the axial direction Da. A suction port 34 is disposed in the second plate portion 32. The suction port 34 penetrates the second plate portion 32 in the axial direction Da. When viewed from the one axial direction Da1 side, the suction port 34 overlaps with the center of the impeller 1 (particularly the hub 11 and the holding portion 122 of the rotor blade 12, which will be described later). The outer edge of the suction port 34 surrounds the rotation axis J.

[0024] The peripheral wall portion 33 is disposed along the outer edge of the first plate portion 31 and the outer edge of the second plate portion 32, and extends in the axial direction Da. One axial end of the peripheral wall portion 33 is connected to the outer edge of the first plate portion 31. The other axial end of the peripheral wall portion 33 is connected to the outer edge of the second plate portion 32. A delivery port 35 is provided in the peripheral wall portion 33. The delivery port 35 penetrates the peripheral wall portion 33 in the radial direction. In other words, the delivery port 35 is provided on the radially outer surface of the housing 3, and opens at least radially radially outward from the impeller 1.

[0025] In the fan device 100, as the impeller 1 rotates about the rotation axis J, the fluid F is sucked in through the suction port 34 and discharged radially outward from the impeller 1. The fluid F flows along the inner surface of the peripheral wall portion 33 inside the housing 3 as viewed from the axial direction Da, and is discharged to the outside of the fan device 100 through the discharge port 35.

[0026] The substrate 4 is electrically connected to, for example, a stator (not shown) of the motor 2, and is also electrically connected to an external circuit of the fan device 100 via a connection wire (not shown) that is drawn to the outside of the fan device 100. Electrical circuits including a motor drive circuit, electrical elements, etc. are mounted on the substrate 4. The substrate 4 is in the shape of a plate that extends radially, and is disposed on one axial side Da1 of the motor 2.

[0027] The fan unit 100 is not limited to the above example, and may be configured without the housing 3. In this case, the motor 2 and the board 4 are fixed to the other side (such as a wall) to which the fan unit 100 is attached.

[0028] <1-2. Impeller Configuration> Next, the detailed configuration of the impeller 1 will be described with reference to Fig. 1 to Fig. 3. Fig. 3 is a perspective view showing an example configuration of the impeller 1 according to the embodiment. As described above, the impeller 1 has a covered cylindrical hub 11 and a plurality of rotor blades 12. The hub 11 is covered cylindrical and extends in the axial direction Da. One axial end of the hub 11 is open. The plurality of rotor blades 12 are arranged radially outward from the hub 11 and aligned in the circumferential direction Dc.

[0029] Preferably, the total number of rotor blades 12 (particularly, the blade portions 121) is a prime number. In a typical fan device, discrete frequency noise (so-called NZ noise) resulting from the product of the number Z of rotor blades 12 and the rotation speed N of the motor 2 is generated, for example, at a corner of the peripheral wall portion 33 of the blower fan 100 (for example, the portion 331 surrounded by a dashed line in FIG. 1 ; so-called tongue portion). In contrast, by making the total number of rotor blades 12 a prime number, interference (resonance) between the order of the rotor blades 12 and the order of magnetic excitation of the motor 2 can be suppressed. However, this example does not exclude a configuration in which the total number of rotor blades 12 is not a prime number. In other words, the total number of rotor blades 12 may be a so-called composite number.

[0030] The hub 11 and the rotor blades 12 may be made of resin or metal. The hub 11 and the rotor blades 12 may be integral (i.e., different parts of a single member) or separate (i.e., different members).

[0031] The hub 11 has a plate portion 111, a cylindrical portion 112, and a holder 113. The plate portion 111 is circular and extends radially outward from the rotation axis J. The cylindrical portion 112 extends from the radially outer end of the plate portion 111 in one axial direction Da1 and surrounds at least the portions of the motor 2 and the shaft 21 on the other axial direction Da2 side. The radially inner surface of the cylindrical portion 112 faces the radially outer surface of the motor 2 with a gap therebetween. The holder 113 is cylindrical and surrounds and accommodates the other axial end of the shaft 21, and is fixed to the shaft 21. The radially inner surface of the holder 113 contacts the radially outer surface of the shaft 21.

[0032] Each rotor blade 12 has a blade portion 121 and a retaining portion 122. The blade portion 121 extends in the axial direction Da and the radial direction, and inclines in one circumferential direction Dc1 toward the other axial direction Da2. The retaining portion 122 extends radially inward from one axial end of the blade portion 121 and is connected to the hub 11. In this embodiment, the retaining portion 122 is connected to one axial end of the radially outer surface of the hub 11. However, the axial connection position of the retaining portion 122 to the hub 11 is not limited to this example. The connection position of the retaining portion 122 may be the axial center of the radially outer surface of the hub 11 or on one axial direction Da1 from the axial center.

[0033] According to the impeller 1 of the fan unit 100 of this embodiment, the retaining portions 122 connected to the hub 11 retain the blade portions 111 of each rotor blade 12. Therefore, it is not necessary to provide an annular plate member (so-called shroud) for retaining the blade portions 111. Furthermore, the total area of ​​one axial end face of the retaining portions 122 of each rotor blade 12 as viewed from one axial direction Da1 is smaller than the area of ​​one axial end face of the above-mentioned plate member. Therefore, when the impeller 1 rotates, friction between the retaining portions 122 and the fluid F can be reduced. In other words, fluid resistance at the retaining portions 122 that retain the blade portions 111 of the impeller 1 can be reduced.

[0034] Furthermore, the retaining portions 122 that are adjacent in the circumferential direction are spaced apart in the circumferential direction Dc. Therefore, the weight of the impeller 1 can be reduced compared to a configuration in which the blade portions 111 are retained by an annular plate member.

[0035] As a result, the torque required to rotate the impeller 1 can be reduced, and the impeller 1 can be rotated with a smaller motor 2. In other words, the motor 2 can be prevented from becoming larger.

[0036] In this embodiment, when viewed from the axial direction Da, at least the radially outer portion of the blade portion 121 inclines toward one circumferential direction Dc1 as it extends radially outward. In other words, the blade portion 121 has a forward-swept blade. However, without being limited to this example, at least the radially outer portion of the blade portion 121 may also incline toward the other circumferential direction Dc1 as it extends radially outward. In other words, the blade portion 121 may have a swept-back blade. Alternatively, at least the radially outer portion of the blade portion 121 may extend straight radially outward.

[0037] In this embodiment, when viewed from one axial direction Da1 side, the radially outer ends of the other axial end portions of the blade portions 121 of the rotor blades 12 are located radially outward from the outer edge of the suction port 34. However, this example does not exclude a configuration in which the radially outer ends of the other axial end portions of the blade portions 121 of at least some of the rotor blades 12 are located at the same position as the outer edge of the suction port 34 or are located radially inward from the outer edge of the suction port 34 when viewed from one axial direction Da1 side.

[0038] Preferably, as viewed from the one axial direction Da1 side, the radially inner ends of the other axial ends of the blade portions 121 in at least some of the rotor blades 12 are positioned radially outward from the outer edge of the suction port 34. More preferably, the blade portions 121 in all of the rotor blades 12 are positioned radially outward from the outer edge of the suction port 34. This makes it possible to increase the flow rate of the fluid F flowing from the suction port 34 between the blade portions 121. Therefore, it is possible to increase the flow rate of the fluid F discharged radially outward by the fan device 100. However, this example does not exclude a configuration in which, as viewed from the one axial direction Da1 side, the radially inner ends of the other axial ends of the blade portions 121 in at least some of the rotor blades 12 are positioned at the same position as the outer edge of the suction port 34 or radially inward from the outer edge of the suction port 34.

[0039] Preferably, the axial width of the radially inner end of each retaining portion 122 is greater than the circumferential width of the radially inner end of each retaining portion 122. This allows more retaining portions 122 to be connected to the other axial end of the hub 11. In other words, more rotor blades 12 can be arranged radially outward from the hub 11. Therefore, when the impeller 1 rotates, it can deliver more fluid F radially outward. However, this example does not exclude a configuration in which the axial width of the radially inner end of each retaining portion 122 is equal to or less than the circumferential width of the radially inner end of each retaining portion 122.

[0040] Next, each rotor blade 12 further has a connection portion 123. In each rotor blade 12, the connection portion 123 extends in one circumferential direction Dc1 from the other axial end of the blade portion 121. In adjacent rotor blades 12 in the circumferential direction Dc, one circumferential end of the connection portion 123 of the rotor blade 12 on the other circumferential direction Dc2 side is connected to the blade portion 121 of the rotor blade 12 on the one circumferential direction Dc1 side, and in particular is connected to the other circumferential end face of the blade portion 121.

[0041] This prevents leakage of the fluid F from the positive pressure surface of the blade portion 121 to the other axial direction Da2 when the impeller 1 is rotated, thereby preventing a decrease in the flow rate of the fluid F being delivered radially outward.

[0042] For example, when the impeller 1 is rotated in one circumferential direction Dc1 around the rotation axis J, the one circumferential end surface of the blade portion 121 becomes a positive pressure surface, and the other circumferential end surface of the blade portion 121 becomes a negative pressure surface. Here, in a configuration in which the other axial end of the blade portion 121 is a free end, a blade tip vortex is generated on the other axial direction Da2 side of the other axial end of the blade portion 121, and the fluid F on the positive pressure surface leaks out to the other axial direction Da2. As a result, leakage loss of the fluid F at the other axial end of the blade portion 121 increases, and the fluid efficiency of the impeller 1 deteriorates.

[0043] On the other hand, as shown in FIG. 3 , by disposing the connecting portion 123 at the other axial end of the blade portion 121, the generation of a tip vortex on the other axial direction side Da2 of the other axial end of the blade portion 121 can be suppressed. In other words, the rotor blade 12 of this embodiment has a toroidal shape in which there is no free end on the suction port 34 side of the blade portion 121 in the axial direction Da. Furthermore, the impeller 1 according to this embodiment is a toroidal fan in which the generation of tip vortexes is suppressed and leakage of the fluid F from the pressure surface (one circumferential end surface) to the other axial direction Da2 is prevented. Therefore, leakage of the fluid F at the other axial end of the blade portion 121 can be prevented. Furthermore, because the generation of tip vortexes is suppressed, turbulent noise caused by pressure fluctuations due to the tip vortex propagating to the surroundings as sound waves can be reduced.

[0044] 2. Remarks The above describes the embodiments of the present invention. Note that the above embodiments are merely examples, and it will be understood by those skilled in the art that various modifications are possible in the combination of each component and each process, and that such modifications are within the scope of the present invention.

[0045] 3. Summary The following provides a summary of the embodiments described above.

[0046] For example, the impeller 1 disclosed in this specification comprises a covered cylindrical hub 11 extending in the axial direction Da and opening at one axial end, and a plurality of moving blades 12 arranged radially outward from the hub 11 and aligned in the circumferential direction Dc, each of the moving blades 12 having a blade portion 121 that extends in the axial direction Da and radial directions and inclines in one circumferential direction Dc1 as it approaches the other axial direction Da2, and a retaining portion 122 that extends radially inward from one axial end of the blade portion 121 and is connected to the hub 11 (first configuration).

[0047] The impeller 1 of the first configuration may be configured (second configuration) such that each of the rotor blades 12 further has a connecting portion 123 extending from the other axial end of the blade portion 121 in one circumferential direction Dc1, and for the rotor blades 12 adjacent in the circumferential direction Dc, one circumferential end of the connecting portion 123 of the rotor blade 12 on the other circumferential direction Dc2 side is connected to the blade portion 121 of the rotor blade 12 on the one circumferential direction Dc1 side.

[0048] Furthermore, the impeller 1 of the first or second configuration may be configured (third configuration) in which the axial width of the radially inner end of the retaining portion 122 is larger than the circumferential width of the radially inner end of the retaining portion 122.

[0049] The fan device 100 disclosed in this specification is a fan device 100 that sends out a fluid F that is sucked in in one axial direction Da1 radially outward, and includes: an impeller 1 having a covered cylindrical hub 11 that extends in the axial direction Da and has one axial end that is open; and a plurality of moving blades 12 that are arranged radially outward from the hub 11 and are aligned in the circumferential direction Dc; and a motor 2 that has a shaft 21 that can rotate together with the impeller 1 about a rotation axis J that extends in the axial direction Da and has at least a portion thereof arranged inside the hub 11, wherein each of the moving blades 12 has a blade portion 121 that extends in the axial direction Da and radial directions and is inclined toward one circumferential direction Dc1 as it approaches the other axial direction Da2, and a retaining portion 122 that extends radially inward from the one axial end of the blade portion 121 and is connected to the hub 11 (fourth configuration).

[0050] The present invention is useful in devices that deliver airflow in a radially outward direction.

[0051] 100... centrifugal fan, 1... impeller, 11... hub, 111... plate portion, 112... cylindrical portion, 113... holder, 12... rotor blade, 121... blade portion, 122... holding portion, 123... connection portion, 2... motor, 21... shaft, 3... housing, 31... first plate portion, 32... second plate portion, 33... peripheral wall portion, 34... suction port, 35... delivery port, 4... substrate, F... fluid, J... rotation axis, Da... axial direction, Da1... one axial direction, Da2... other axial direction, Dc... circumferential direction, Dc1... one circumferential direction, Dc2... other circumferential direction

Claims

1. An impeller comprising: a covered, cylindrical hub extending axially and opening at one axial end; and a plurality of rotor blades arranged circumferentially and positioned radially outward from the hub, each of the rotor blades having a blade portion that extends axially and radially and is inclined to one circumferential direction as it approaches the other axial direction; and a retaining portion that extends radially inward from one axial end of the blade portion and is connected to the hub.

2. An impeller as set forth in claim 1, wherein each of the rotor blades further has a connection portion extending in one circumferential direction from the other axial end of the blade portion, and for circumferentially adjacent rotor blades, one circumferential end of the connection portion of the rotor blade on the other circumferential side is connected to the blade portion of the rotor blade on the one circumferential side.

3. An impeller as set forth in claim 1, wherein the axial width of the radially inner end of said retaining portion is greater than the circumferential width of the radially inner end of said retaining portion.

4. A fan device which sends out fluid sucked in one axial direction radially outward, comprising: an impeller having a covered cylindrical hub extending axially and opening at one axial end, and a plurality of moving blades arranged circumferentially and positioned radially outward from the hub; and a motor having a shaft which can rotate together with the impeller about a rotation axis extending axially, and at least a portion of which is positioned inside the hub, wherein each of the moving blades has a blade portion which extends in the axial and radial directions and which is inclined to one circumferential direction as it approaches the other axial direction, and a retaining portion which extends radially inward from one axial end of the blade portion and is connected to the hub.

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