CENTRIFUGAL BLOWER

Abstract

A centrifugal blower has: a housing (2); an electric motor (3) supported by the housing at a motor support position (32a) of the electric motor; and a fan (4) designed to be driven and rotated by the electric motor. The fan has: a hub (41) installed on an output shaft (31) of the electric motor at a location on one side relative to the motor support position in an axial direction of the output shaft; a main plate (42) extending outward from the hub in a radial direction of the output shaft; a plurality of blades (43) extending from the main plate to one side in the axial direction of the output shaft; and a side plate (44) joined to an end section of each of the plurality of blades facing one side in the axial direction of the output shaft. The weight of the main plate is greater than the weight of the side plate.The main plate and the side plate both tilt towards a different side, opposite to one side in the axial direction of the output shaft, with the main plate and the side plate approaching an outer side in the radial direction.

Description

CROSS REFERENCE TO RELATED APPLICATION

[0001] This application is based on Japanese Patent Application No. 2022-018149 filed on February 8, 2022, and is incorporated herein by reference. TECHNICAL FIELD

[0002] The present disclosure relates to a centrifugal blower. TECHNICAL BACKGROUND

[0003] According to Patent Document 1, an object is to reduce an axial distance measured in a direction parallel to a rotation axis of an impeller from a vertical plane passing through a joint between a hub and a main plate of the impeller and perpendicular to the rotation axis to a center of gravity of the impeller in a turbofan. It is disclosed in Patent Document 1 to form the main plate such that a plate thickness of the main plate progressively increases from the rotation axis side to an outer periphery of the main plate to achieve the above-described object. CITATION LISTPATENT LITERATURE

[0004] PATENT LITERATURE 1: JP 2010-281256 A SUMMARY OF THE INVENTION

[0005] According to the studies of the present inventors, it is desirable to reduce the amount of positional deviation measured in an axial direction of the rotation axis between the center of gravity of the impeller and a motor support position, which is a position where an electric motor is supported by a casing, in the turbofan of Patent Literature 1. This is because if the amount of positional deviation increases, it increases a moment around the motor support position in response to a centrifugal force generated by a complex imbalance of the fan and a motor rotor, thereby potentially insufficiently restricting vibrations of the turbofan. This applies not only to the turbofan but to a centrifugal blower in general.It is an object of the present disclosure to reduce the amount of positional deviation measured in an axial direction of a rotation axis between a center of gravity of a fan and a motor support position in a centrifugal blower.

[0006] According to one aspect of the present disclosure, there is provided a centrifugal blower having: a housing; an electric motor supported by the housing at a motor support position of the electric motor; and a fan designed to be driven and rotated by the electric motor, wherein the fan has the following: a hub installed on an output shaft of the electric motor at a location that is on one side relative to the motor support position in an axial direction of the output shaft; a main plate extending outward from the hub in a radial direction of a center axis of the output shaft; a plurality of blades extending from the main plate to one side in the axial direction of the output shaft; and a side plate joined to an end portion of each of the plurality of blades facing the one side in the axial direction of the output shaft, wherein a weight of the main plate is greater than a weight of the side plate; and the main plate and the side plate are both inclined to another side opposite to the one side in the axial direction of the output shaft, with the main plate and the side plate approaching an outer side in the radial direction.

[0007] Since the weight of the main plate, which is located on the other side relative to the side plate in the axial direction of the output shaft, is greater than the weight of the side plate, it is possible to reduce the amount of positional deviation measured between the motor support position and the center of gravity of the fan in the axial direction of the output shaft. Furthermore, since the main plate and the side plate are both inclined toward the other side in the axial direction of the output shaft, with the main plate and the side plate approaching the outer side in the radial direction, the plurality of blades can be offset toward the other side in the axial direction of the output shaft, so that the center of gravity of the fan can be offset toward the other side in the axial direction.That is, it is possible to reduce the amount of positional deviation measured between the motor support position and the center of gravity of the fan in the axial direction of the output shaft.

[0008] A parenthesized reference numeral attached to each component indicates an example of correspondence between the component and a specific component described in embodiments described later. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a cross-sectional view of a centrifugal blower of a first embodiment taken along a plane including a rotation axis of the centrifugal blower. Fig. 2 is a cross-sectional view taken along a line II-II in Fig. 1. Fig. 3 is a cross-sectional view taken along a line III-III in Fig. 1. Fig. 4 is a cross-sectional view along a line IV-IV in Fig. 1. Fig. 5 is a cross-sectional view of a centrifugal blower of a second embodiment taken along a plane including a rotation axis of the centrifugal blower. Fig. 6 is a plan view of a fan taken from the other side in an axial direction. Fig. 7 is a plan view of a fan of a third embodiment taken from the other side in the axial direction. Fig. 8 is a plan view of a fan of a fourth embodiment taken from the other side in the axial direction. Fig. 9 is a cross-sectional view of a centrifugal blower of a fifth embodiment, taken along a plane including a rotation axis of the centrifugal blower. Fig. 10 is a cross-sectional view of a centrifugal blower of a sixth embodiment, taken along a plane including a rotation axis of the centrifugal blower. Fig. 11 is a cross-sectional view of a centrifugal blower of a seventh embodiment, taken along a plane including a rotation axis of the centrifugal blower. Fig. 12 is a cross-sectional view taken along a line XII-XII in Fig. 11. DESCRIPTION OF THE EMBODIMENTS

[0009] Embodiments of the present disclosure will be described below. In the following embodiments, the same reference numerals may be assigned to portions that are the same as or equivalent to those described in the preceding embodiment(s), and the description thereof may be omitted. Furthermore, when only one or more of the components is / are described in the embodiment, the description of the remaining components in the preceding embodiment may be applied to the remaining components. The following embodiments may be partially combined with each other as long as the combination does not cause a problem, even if it is not explicitly noted. (First embodiment)

[0010] As in Fig. 1, a centrifugal blower 1 of a first embodiment includes: a casing 2; an electric motor 3 supported by the casing 2; and a fan 4 driven and rotated by the electric motor 3. Fig. 1 is a cross-sectional view of the centrifugal blower 1 taken along a plane including a rotation axis CL of the centrifugal fan 1. The centrifugal fan 1 of the present embodiment is a turbo fan, but as another example, a centrifugal blower other than the turbo fan (for example, a sirocco fan) may be used.

[0011] The housing 2 is a component that houses the electric motor 3 and the fan 4. The housing 2 is made of resin, for example, but it may be made of any other suitable materials. The housing 2 may be attached to another component (for example, a casing forming an outer shell of an air conditioning device).

[0012] The housing 2 has a first housing portion 21 and a second housing portion 22. The first housing portion 21 and the second housing portion 22 may be formed separately and assembled together, or the first housing portion 21 and the second housing portion 22 may be integrally formed in one piece. The first housing portion 21 covers an intake side of the fan 4, and the second housing portion 22 covers an opposite side of the fan 4, which is opposite to the intake side. The electric motor 3 is installed in the second housing portion 22.

[0013] The electric motor 3 has an output shaft 31, a rotatable body holder 32, a bearing 33, a core 34, and a rotor 35. The electric motor 3 is an outer rotor electric motor, but as another example, it may be an inner rotor electric motor.

[0014] The output shaft 31 is a rod that transmits a rotational force generated by the electric motor 3 to the fan 4. A central axis of the output shaft 31 and the rotation axis CL are substantially coaxial with each other. The rotatable body holder 32 is a member made of, for example, metal or resin. The rotatable body holder 32 is securely installed in the second housing portion 22 at a motor support position 32a of the rotatable body holder 32. Secure installation of the rotatable body holder 32 to the second housing portion 22 can be realized by fixing the rotatable body holder 32 to the second housing portion 22 by bolts or screws or any other means.

[0015] The motor support position 32a is located on an outer side relative to an outermost circumference of the rotor 35 in a radial direction of the central axis of the output shaft 31. Furthermore, the motor support position 32a is placed on the outer side relative to a position of a connection between a hub 41 (which will be described later) and the output shaft 31 in the radial direction of the central axis of the output shaft 31. Furthermore, the motor support position 32a is located on a lower side in Fig. 1 in an extending direction of the output shaft 31 relative to the position of the connection between the hub 41 and the output shaft 31 and also a position of a connection between the rotor 35 and the output shaft 31.

[0016] Hereinafter, the extending direction of the output shaft 31 is referred to as an axial direction FL. Furthermore, an upper side in Fig. 1 in the axial direction FL is referred to as a side, and a lower side in Fig. 1 in the axial direction FL is referred to as the other side. Furthermore, a radial direction of the center axis of the output shaft 31 is simply referred to as a radial direction, and a circumferential direction around the center axis of the output shaft 31 is simply referred to as a circumferential direction.

[0017] The bearing 33 is installed on a surface of the rotatable body holder 32 facing the output shaft 31, and the bearing 33 rotatably supports the output shaft 31. With the above-described configuration, the rotatable body holder 32 supports the output shaft 31, the rotor 35, and the fan 4 through the bearing 33.

[0018] The core 34 generates a magnetic field in response to excitation of the core 34 to drive and rotate the rotor 35. The core 34 is fixed to the rotatable body holder 32. The rotatable body holder 32 and the core 34 form a stator.

[0019] The rotor 35 is fixed to the output shaft 31 at an inner periphery of the rotor 35 facing an inner side in the radial direction, and an outer periphery of the rotor 35 facing the outer side in the radial direction is placed on the outer side relative to the core 34 in the radial direction. The rotor 35 has magnets. The magnets are placed on the outer side relative to the core 34 in the radial direction. The rotor 35 receives a rotating force from the magnetic field generated by the core 34 by the action of the magnets. In the electric motor 3, the magnetic field is generated in response to the energization of the core 34, and the rotor 35 is rotated integrally with the output shaft 31 by the magnetic field. At this time, the output shaft 31 is rotatably supported by the bearing 33.

[0020] The fan 4 includes the hub 41, a main plate 42, a plurality of blades 43, and a side plate 44. In the present embodiment, the hub 41, the main plate 42, the blade 43, and the side plate 44 are made of a common material (e.g., resin) as a whole and are integrally molded into one piece. Furthermore, a mass density of the fan 4 is uniform. The hub 41 is a member formed in a ring shape and installed on the output shaft 31. Furthermore, the connection position between the hub 41 and the output shaft 31 is placed on one side in the axial direction FL relative to the connection position between the rotor 35 and the output shaft 31 and also the motor support position 32a.

[0021] The main plate 42 is a member formed in a plate shape. The main plate 42 is joined to the hub 41 at an inner periphery of the main plate 42, which faces the inner side in the radial direction of the central axis of the output shaft 31, and extends from the hub 41 to the outer side in the radial direction. Each of the blades 43 is a member formed in a plate shape. Each blade 43 extends to the one side in the axial direction FL from a surface of the main plate 42 facing the one side in the axial direction FL and is joined to the side plate 44 at an end portion of the blade 43 facing the one side in the axial direction FL. The blades 43 are arranged circumferentially around the central axis of the output shaft 31.Each blade 43 extends such that the blade 43 is offset toward a rear side in a rotational direction of the fan 4 the farther it is from the output shaft 31. The direction of rotation coincides with the circumferential direction.

[0022] The side plate 44 is a member formed in a plate shape. The side plate 44 surrounds the output shaft 31 and extends to the outer side in the radial direction. As described above, the blades 43 are joined to the surface of the side plate 44 facing the other side in the axial direction FL. Furthermore, the first housing portion 21 faces a surface of the side plate 44 facing one side in the axial direction FL and covers the side plate 44 from one side in the axial direction FL.

[0023] The side plate 44 has a main body 44a and a tubular portion 44b. The main body 44a opposes the main plate 42 and holds the vanes 43 between the main plate 42 and the main body 44a. The tubular portion 44b is formed in a tubular shape and extends from an inner peripheral end portion of the main body 44a facing the inner side in the radial direction and extends to one side in the axial direction FL, while the tubular portion 44b is bent relative to the main body 44a. The tubular portion 44b opposes the output shaft 31 and surrounds the output shaft 31 to form an intake port IP for intake of air on the inner side relative to the tubular portion 44b in the radial direction.

[0024] The hub 41, the main plate 42, the blades 43, and the side plate 44, which are configured as described above, are integrally integrated when the rotational force is transmitted from the output shaft 31. Therefore, the output shaft 31, the rotor 35, and the fan 4 rotate integrally toward a front side in the rotation direction.

[0025] Next, an operation of the centrifugal blower 1 configured as described above will be described. When the core 34 of the electric motor 3 is energized, the core 34 generates a magnetic force, and the rotor 35 is driven and rotated by this magnetic force. Therefore, the rotor 35, the output shaft 31, and the fan 4 are integrally rotated. Thus, the air flow is sucked into the intake port IP from one side to the other side in the axial direction FL, and then flows from the inner side to the outer side in the radial direction between the main plate 42 and the side plate 44 through each passage defined between corresponding adjacent two of the blades 43, and is discharged from an outermost periphery of the fan 4 to the outer side in the radial direction.

[0026] In the centrifugal fan 1, there is a complex imbalance between the fan 4 and the rotor 35. This imbalance is caused by the fact that the mass of the rotating body around the rotation axis is not evenly distributed in the circumferential direction (for example, due to eccentricity). Here, the rotating body is formed by the fan 4 and the rotor 35. A moment around the motor support position 32a, generated by a centrifugal force F due to this imbalance, causes vibrations of the centrifugal fan 1. If this moment increases, vibrations of the centrifugal fan 1 cannot be sufficiently restrained. Furthermore, this moment increases as the amount L of positional deviation measured in the axial direction FL between the motor support position 32a and a center of gravity G of the fan 4 increases.The centrifugal blower 1 of the present embodiment is designed to limit the amount L of positional deviation.

[0027] The characteristic features of this centrifugal blower 1 will be described in further detail. First, both the main plate 42 and the side plate 44 incline toward the other side in the axial direction FL as the main plate 42 and the side plate 44 approach the outer side in the radial direction. That is, each of the main plate 42 and the side plate 44 extends toward the other side in the axial direction FL as each of the main plate 42 and the side plate 44 approach the outer side in the radial direction.

[0028] With the above-described configuration, the blades 43 can be displaced to the other side in the axial direction FL, so that the center of gravity G of the fan 4 can be displaced to the other side in the axial direction FL. Therefore, the amount L of positional deviation can be limited, and thereby the vibrations of the centrifugal fan 1 caused by the imbalance can be limited.

[0029] Furthermore, a weight of the main plate 42 is larger than a weight of the side plate 44. Thus, the center of gravity G of the fan 4 can be placed closer to the main plate 42, and thereby the center of gravity G can be shifted to the other side in the axial direction FL to reduce the amount L of positional deviation.

[0030] (1) Specifically, a plate thickness of the main plate 42 is greater than a plate thickness of the side plate 44. This comparison is obvious in a case where the plate thickness of the main plate 42 and the plate thickness of the side plate 44 are uniform. If this is not the case, then the comparison is made based on an average plate thickness of the main plate 42 and an average plate thickness of the side plate 44. The average plate thickness is a value obtained by dividing a volume of the plate by a surface area of ​​a plate surface of the plate.

[0031] By realizing the difference between the plate thickness of the main plate 42 and the plate thickness of the side plate 44 in the manner described above, it is possible to reduce the amount of positional deviation measured between the motor support position and the center of gravity of the fan in the axial direction of the output shaft.

[0032] (2) Further, a length h1 is defined as a length measured axially from one end of the fan 4 facing one side in the axial direction FL to another end of the fan 4 facing the other side in the axial direction FL. This length h1 is also referred to as a total height of the fan 4. Furthermore, a length h2 is defined as a length measured axially from a position of a connection between the hub 41 and the output shaft 31 to the other end of the fan 4 facing the other side in the axial direction FL. The length h2 is also referred to as a height of the hub 41. In this case, the length h2 is equal to or greater than one half of the length h1.

[0033] Therefore, the inclination gradient of the main plate 42, which is joined to the hub 41 and inclined as described above, can be made steeper, and thereby, with respect to the overall height of the fan 4, the blades 43 can be displaced further to the other side in the axial direction FL. Consequently, the amount L of positional deviation can be reduced.

[0034] (3) Furthermore, the main plate 42 has a first chamfer portion 42a and a second chamfer portion 42b. In the main plate 42, the first chamfer portion 42a is located on the inner side relative to the second chamfer portion 42b in the radial direction. Furthermore, one end of the first chamfer portion 42a facing the inner side in the radial direction is joined to the hub 41.

[0035] The first slope portion 42a has a slope gradient that slopes toward the other side in the axial direction FL as the first slope portion 42a approaches the outer side in the radial direction, and the slope gradient of the first slope portion 42a is within a first range. This slope is an amount that increases as the amount of displacement toward the other side in the axial direction FL increases in a case where a distance from the output shaft 31 is increased by a unit length. Specifically, this is a depression angle. Further, the slope is specified based on a position of a midpoint between an end of the slope portion facing one side in the axial direction FL and an end of the slope portion facing the other side in the axial direction FL.

[0036] The second slope portion 42b has a slope gradient that slopes toward the other side in the axial direction FL as the second slope portion 42b approaches the outer side in the radial direction, and the slope gradient of the second slope portion 42b is within a second range different from the first range. The first range and the second range may partially overlap, or the first range and the second range may not overlap at all. This allows for greater flexibility in devising ways to reduce the amount L of positional deviation, compared to the case where the slope of the main plate 42 is constant along its entire extent.

[0037] (4) Furthermore, the first region is steeper than the second region. In other words, an upper limit of the first region of the gradient is greater than an upper limit of the second region of the gradient, and a lower limit of the first region is greater than a lower limit of the second region. Furthermore, an average of the upper and lower limits of the first region is greater than an average of the upper and lower limits of the second region.

[0038] With this configuration, the second chamfer portion 42b, which can be more voluminous because the second chamfer portion 42b is located radially outward from the first chamfer portion 42a, can be arranged more to the other side in the axial direction FL. Consequently, the amount L of positional deviation can be reduced.

[0039] (5) Furthermore, an average plate thickness of the second slope portion 42b is larger than an average plate thickness of the first slope portion 42a. By increasing the average plate thickness of the second slope portion 42b, which is located closer to the other side in the axial direction FL from the first slope portion 42a and the second slope portion 42b in the main plate 42, the amount L of positional deviation can be effectively reduced.

[0040] Here, although in the present embodiment, the average plate thickness of the second slope portion 42b is greater than an average plate thickness of the side plate 44, in another example, the average plate thickness of the second slope portion 42b may not be greater than the average plate thickness of the side plate 44. Furthermore, the average plate thickness of the first slope portion 42a may be greater than the average plate thickness of the side plate 44 or may be smaller than the average plate thickness of the side plate 44.

[0041] (6) Furthermore, the main plate 42 has an outer peripheral end portion 42c located at an outermost periphery of the main plate 42 on the outer side relative to the second slope portion 42b in the radial direction. An average plate thickness of the outer peripheral end portion 42c is smaller than the average plate thickness of the second slope portion 42b. Thus, in the main plate 42 that inclines toward the other side in the axial direction FL as the main plate 42 approaches the outer side in the radial direction, by reducing the plate thickness of the outer peripheral end portion 42c, it is possible to limit the height of the fan 4, that is, the length of the fan 4 measured axially from the end of the fan 4 facing one side in the axial direction FL to the other end of the fan 4 facing the other side in the axial direction FL.

[0042] Specifically, an inclination gradient of a surface of the outer peripheral end portion 42c facing one side in the axial direction FL is larger than an inclination gradient of a surface of the outer peripheral end portion 42c facing the other side in the axial direction FL. Thus, the outer peripheral end portion 42c tapers toward the outer side in the radial direction. For example, the surface of the outer peripheral end portion 42c facing one side in the axial direction FL may extend with a positive gradient toward the other side in the axial direction FL, and the surface of the outer peripheral end portion 42c facing the other side in the axial direction FL may be set such that the position of this surface in the axial direction FL does not change as this surface approaches the outer side in the radial direction.

[0043] By progressively reducing the plate thickness of the outer peripheral end portion 42c toward the outer side in the radial direction, excessive inclination of the surface of the outer peripheral end portion 42c facing the other side in the axial direction FL toward the other side in the axial direction FL is limited. As another example, the position of the surface of the outer peripheral end portion 42c facing the other side in the axial direction FL may progressively approach one side or the other side in the axial direction FL as the outer peripheral end portion 42c approaches the outer side in the radial direction.

[0044] (7) Furthermore, as in Fig. 2, each corner R1a, R1b of a joint between each blade 43 and the main plate 42 is a rounded corner. Furthermore, as shown in Fig. 3, each corner R2a, R2b of a joint between each blade 43 and the side plate 44 is a rounded corner. For each blade 43, a radius of curvature of the corner R1a, R1b is greater than a radius of curvature of the corner R2a, R2b. Note that the corner R2a, R2b may be a right-angled corner. Even in such a case, for each blade 43, a radius of curvature of a corner R1a, R1b is greater than a radius of curvature of a corner R2a, R2b.

[0045] Specifically, the comparison is made between an average radius of curvature of the corner R1a, R1b of the joint with the main plate 42 and an average radius of curvature of the corner R2a, R2b of the joint with the side plate 44. Here, the average radius of curvature of the corner R1a, R1b is obtained by averaging a radius of curvature at respective points located from an inner end of the corner R1a, R1b facing the inner side in the radial direction to an outer end of the corner R1a, R1b facing the outer side in the radial direction. Furthermore, the average radius of curvature of the corner R2a, R2b is obtained by averaging a radius of curvature at respective points located from an inner end of the corner R2a, R2b facing the inner side in the radial direction to an outer end of the corner R2a, R2b facing the outer side in the radial direction.

[0046] Therefore, in each blade 43, the joint with the main plate 42 is thicker than the joint with the side plate 44. By realizing the difference between the radius of curvature of the corner at the main plate side and the radius of curvature of the corner at the side plate side in the manner described above, it is possible to reduce the amount of positional deviation measured between the motor support position 32a and the center of gravity G of the fan 4 in the axial direction of the output shaft 31.

[0047] All of the plurality of blades 43 or at least one (or more) of the plurality of blades 43 may be configured as the blade having the above-described relationship between the corners R1a, R1b, R2a, R2b. When the above-described relationship is satisfied in the at least one blade 43 of the plurality of blades 43, the at least one blade 43 can realize the above-described advantage.

[0048] (8) Furthermore, as in Fig. 2 and Fig. 4, the radius of curvature of each corner R1a, R2a of the joint between the at least one blade 43 and the main plate 42 increases toward the outer side in the radial direction. This increase may be a continuous increase or a stepwise increase. The increase in the radius of curvature of each corner R1a, R2a toward the outer side in the radial direction described above may be only for a part of the joint between the blade 43 and the main plate 42 (for example, only the joint between the blade 43 and the second chamfer portion 42b).

[0049] By implementing the change in the radius of curvature of the corner in the radial direction of the blade 43 as described above, it is possible to reduce the amount of positional deviation measured between the motor support position 32a and the center of gravity G of the fan 4 in the axial direction of the output shaft 31. This is because the main plate 42 tilts toward the other side in the axial direction of the output shaft 31 as the main plate 42 approaches the outer side in the radial direction.

[0050] (9) Furthermore, as in Fig. 1, a leading edge 43a, which is an end portion facing the output shaft 31, of each of the plurality of blades 43 has an end portion facing one side in the axial direction FL, and the one end portion of the leading edge 43a is joined to a surface of the tubular portion 44b facing the output shaft 31.

[0051] With this configuration, the rigidity of each blade 43 is improved, and thereby deformation of the fan 4 can be restricted. This configuration can be implemented in all of the plurality of blades 43 as described above, or in at least one (or more) of the plurality of blades 43. Even in the latter case, the rigidity of at least one (or more) of the plurality of blades 43 is improved.

[0052] In the present embodiment, the plate thickness of the remainder of each blade 43 other than the joint with the main plate 42 and the joint with the side plate 44 is constant. Furthermore, the surface of the main plate 42 of the present embodiment facing the other side in the axial direction FL does not have any projection(s) such as a rib(s). (Second embodiment)

[0053] Next, a second embodiment will be described with reference to Fig. 5 and Fig. 6. The centrifugal fan 1 of the present embodiment differs from the first embodiment in the design of the main plate 42. In particular, as shown in Fig. 5 and Fig. 6, the main plate 42 has a plurality of ribs 42d. Furthermore, although the plate thickness of the outer peripheral end portion 42c of the present embodiment is the same as the plate thickness of the second slope portion 42b, the plate thickness of the outer peripheral end portion 42c may be smaller than the plate thickness of the second slope portion 42b, as in the first embodiment. The rest of the structure of the present embodiment is the same as that of the first embodiment.

[0054] The ribs 42d protrude to the other side in the axial direction FL from the surface of the main plate 42, which is opposite to the side plate 44 in the axial direction FL. Each rib 42d is formed in a ring shape with its center on the central axis of the output shaft 31 and surrounds the output shaft 31. These ribs 42d are arranged in a row from the inner side to the outer side in the radial direction as a whole. The number of ribs 42d may be multiple (a plurality) or one. Furthermore, the ribs 42d may be provided only on the second slope portion 42b, as shown in Fig. 5 and Fig. 6, or may be provided on both the first bevel portion 42a and the second bevel portion 42b or only on the first bevel portion 42a.

[0055] Furthermore, in the present embodiment, an outermost portion of the main plate 42, which is outermost on the other side in the axial direction FL, is not one of the ribs 42d, but the end portion of the outer peripheral end portion 42c facing the other side in the axial direction FL. This reduces a possibility that the ribs 42d will increase the dimension of the fan 4 measured in the axial direction FL.

[0056] (1) As described above, the main plate 42 has at least one rib 42d projecting to the other side in the axial direction of the output shaft 31 from the surface of the main plate 42 opposite to the side plate 44. With this configuration, the amount L of positional deviation can be reduced by the amount corresponding to the weight of the rib(s) 42d.

[0057] (2) Furthermore, each rib 42d is formed in the ring shape surrounding the output shaft 31. With this configuration, the rib 42d is less likely to form a resistance to the rotation of the fan 4. Furthermore, each rib 42d may have a center on the central axis of the output shaft 31, as described above, or may have a center offset from the central axis of the output shaft 31. Furthermore, the ribs 42d may be formed only at the second slope portion 42b, as shown in Fig. 6, or may be formed on both the first slope portion 42a and the second slope portion 42b. Furthermore, the structure of the present embodiment, which is the same as or similar to the structure of the first embodiment, can achieve the advantage(s) similar to the advantage(s) of the structure of the first embodiment. (Third embodiment)

[0058] Next, a third embodiment will be described with reference to Fig. 7. In the centrifugal blower 1 of the present embodiment, the plurality of fins 42d of the second embodiment are replaced by a plurality of fins 42e. The rest of the structure of the present embodiment is the same as that of the second embodiment. Each of the fins 42e is formed in a star shape, which is star-shaped with respect to the center axis of the output shaft 31 from the inner side to the outer side in the radial direction.

[0059] Furthermore, in the present embodiment, an outermost portion of the main plate 42 which is outermost on the other side in the axial direction FL is not one of the ribs 42e but the end portion of the outer peripheral end portion 42c facing the other side in the axial direction FL.

[0060] The number of ribs 42e may be multiple (a plurality) or one. Furthermore, the ribs 42e may be provided only on the second slope portion 42b, as shown in Fig. 7, or may be provided on both the first bevel section 42a and the second bevel section 42b or only on the first bevel section 42a.

[0061] Furthermore, in the present embodiment, one or a plurality of ribs 42d formed in a manner described in the second embodiment may be additionally provided. Specifically, a combination of the rib(s) 42d and the rib(s) 42e may be formed on the main plate 42. Furthermore, the structure of the present embodiment, which is the same as or similar to the structure of one or more of the first and second embodiments, can achieve the advantage(s) similar to the advantage(s) of the structure of one or more of the first and second embodiments. (Fourth embodiment)

[0062] Next, a fourth embodiment will be described with reference to Fig. 8. In the centrifugal blower 1 of the present embodiment, the plurality of fins 42e of the third embodiment are replaced by a plurality of fins 42f. The rest of the structure of the present embodiment is the same as that of the third embodiment.

[0063] The ribs 42f are arranged in the circumferential direction around the central axis of the output shaft 31. Furthermore, each of the ribs 42f is formed in a vane shape extending such that the farther the rib 42f is offset toward the rear in the rotational direction, the farther it is from the output shaft 31. That is, the orientation of each of the ribs 42f is the same as the orientation of each of the vanes 43.

[0064] As another example, the orientation of each of the ribs 42f may be opposite to the orientation of each of the blades 43. Specifically, each of the ribs 42f may be formed into a different vane shape extending such that the farther the rib 42f is offset toward the front in the rotational direction, the farther it is from the output shaft 31. Furthermore, the number of ribs 42f may be the same as the number of blades 43 or may be different. The number of ribs 42f may be one.

[0065] Furthermore, in the present embodiment, an outermost portion of the main plate 42 which is outermost on the other side in the axial direction FL is not one of the ribs 42f but the end portion of the outer peripheral end portion 42c facing the other side in the axial direction FL.

[0066] The number of ribs 42f may be multiple (a plurality) or one. Furthermore, the ribs 42f may be provided only on the second slope portion 42b, as shown in Fig. 8, or they may be provided on both the first slope portion 42a and the second slope portion 42b, or they may be provided only on the first slope portion 42a. Furthermore, the structure of the present embodiment, which is the same as or similar to the structure of one or more of the first to third embodiments, can achieve the advantage(s) similar to the advantage(s) of the structure of one or more of the first to third embodiments. (Fifth embodiment)

[0067] Next, a fifth embodiment will be described with reference to Fig. 9. The centrifugal blower 1 of the present embodiment differs from the first embodiment in the configuration of the hub 41 and the configuration of the main plate 42. The rest of the structure of the present embodiment is the same as that of the first embodiment. The modification in the present embodiment can also be applied to any of the second to fourth embodiments.

[0068] The hub 41 and the main plate 42 of the present embodiment are made of a material having a mass density higher than a mass density of a material of the side plate 44, the blades 43, and the side plate 44. The material of the hub 41 and the main plate 42 can be a resin or a metal. Thus, the weight of the main plate 42 is increased compared to the third embodiment, and thereby the center of gravity G of the fan 4 is shifted to the other side in the axial direction FL.

[0069] In the present embodiment, the hub 41 and the main plate 42 may be formed separately from the blades 43 and the side plate 44, and then the blades 43 and the main plate 42 may be joined together by welding, for example, to form the fan 4. Alternatively, the hub 41 and the main plate 42 may be formed together with the blades 43 and the side plate 44 by a two-color injection molding process.

[0070] The hub 41 may be formed of the same material as the blades 43 and the side plate 44, as in the first embodiment. Alternatively, the blades 43 may be made of the same material as the main plate 42. In either case, the advantage similar to that described above can be achieved.

[0071] (1) As described above, the main plate 42 is made of the material having the mass density higher than the mass density of the material of the side plate 44. In this way, by making the material of the main plate 42 and the material of the side plate 44 different from each other in the manner described above, the amount L of positional deviation can be reduced. Furthermore, the structure of the present embodiment, which is the same as or similar to the structure of one or more of the first to fourth embodiments, can achieve the advantage(s) equal to the advantage(s) of the structure of one or more of the first to fourth embodiments. (Sixth embodiment)

[0072] Next, a sixth embodiment will be described with reference to Fig. 10. The centrifugal blower 1 of the present embodiment differs from the first embodiment in the material of the fan 4. The rest of the structure of the present embodiment is the same as that of the first embodiment. The modification as in the present embodiment can also be applied to any of the second to fifth embodiments.

[0073] In the present embodiment, the remaining components of the fan 4 other than the main plate 42, such as the hub 41, the blades 43, and the side plate 44, are all made of resin. In the main plate 42, as shown in Fig. As shown in Figure 10, the first slope portion 42a and the outer peripheral end portion 42c are made of resin. The second slope portion 42b includes: a metal portion made of metal; and a resin portion made of resin and surrounding the metal portion. This metal has a mass density higher than the mass density of the resin described above. Therefore, the mass density of the main plate 42 is higher than the mass density of the side plate 44.

[0074] The fan 4 having the above-described structure can also be manufactured by a resin molding process in which the metal is inserted into the resin, that is, by an insert molding process. Like the second slope portion 42b, the first slope portion 42a and the outer peripheral end portion 42c can be partially made of metal.

[0075] (1) As described above, the second slope portion 42b includes: the metal portion; and the resin portion surrounding the metal portion. By increasing the weight of the main plate in the manner described above, the amount L of positional deviation can be reduced. Furthermore, the structure of the present embodiment, which is the same as or similar to one or more of the first to fifth embodiments, can achieve the advantage(s) similar to the advantage(s) of one or more of the first to fifth embodiments. (Seventh embodiment)

[0076] Next, a seventh embodiment will be described with reference to Fig. 11 and Fig. 12. The centrifugal blower 1 of the present embodiment differs from the first embodiment in the configuration of the blades 43. The rest of the structure of the present embodiment is the same as that of the first embodiment. The modification in the present embodiment can also be applied to any of the second to sixth embodiments.

[0077] Each of the blades 43 of the present embodiment satisfies that a plate thickness of a portion of the blade 43 that is closer to the main plate 42 than to the side plate 44 is greater than a plate thickness of another portion of the blade 43 that is closer to the side plate 44 than to the main plate 42. Specifically, as shown in Fig.12, a plate thickness of a main body of each blade 43, which is different from the joint with the main plate 42 and the joint with the side plate 44, progressively decreases as the main body moves away from the main plate 42 and approaches the side plate 44. In addition to the above-described configuration in which the plate thickness of the main body of the blade 43 progressively decreases as the main body moves away from the main plate 42 and approaches the side plate 44, the plate thickness of the main body may decrease in a stepwise manner.

[0078] (1) As described above, each of the blades 43 satisfies that the plate thickness of the portion of the blade 43 closer to the main plate 42 is greater than the plate thickness of the other portion of the blade 43 closer to the side plate 44. By setting the plate thickness differently between the portion of the blade 43 closer to the main plate 42 and the other portion of the blade 43 closer to the side plate 44 in the manner described above, the amount L of positional deviation can be reduced.

[0079] Instead of all of the plurality of blades 43, only one or more of the plurality of blades 43 may be configured as the blade 43 having the above-described characteristic. That is, the advantage(s) described above can be achieved to some extent as long as the one or more of the blades 43 having the above-described characteristic is / are provided. (Other embodiments)

[0080] The present disclosure is not limited to the above embodiments, and the above embodiments may be appropriately modified. Furthermore, the above embodiments are not unrelated to each other and may be appropriately combined unless the combination is clearly impossible. Furthermore, in each of the above-described embodiments, the elements of the embodiment are not necessarily essential unless it is clearly indicated that they are essential and they are clearly considered essential in principle.In each of the above embodiments, when a numerical value such as the number, numerical value, amount, range, or the like of the constituent elements of the embodiment is mentioned, the present disclosure should not be limited to such a numerical value unless it is clearly stated that it is essential and / or required by principle. Furthermore, when multiple values ​​are shown for a given quantity, it is also possible to use a value between these multiple values ​​unless specifically stated otherwise and unless it is clearly impossible by principle.In each of the above embodiments, when the shape, positional relationship, or the like of the constituent elements of the embodiment are mentioned, the present disclosure should not be limited to the shape, positional relationship, or the like unless clearly stated as essential and / or required by principle. Furthermore, the present disclosure also allows the following variations and variations of an equivalent scope to each of the above present embodiments. Application and non-application of the following variations to the embodiments described above can be independently selected. In other words, any combination of the following variations can be applied to the above-described embodiments. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] JP 2022-018149

[0001] JP 2010-281256 A

[0004]

Claims

[1] Centrifugal blower with: a housing (2); an electric motor (3) supported by the housing (2) at a motor support position (32a) of the electric motor (3); and a fan (4) designed to be driven and rotated by the electric motor (3), wherein the fan (4) has the following: a hub (41) installed on an output shaft (31) of the electric motor (3) at a position that is on one side relative to the motor support position (32a) in an axial direction of the output shaft (31); a main plate (42) extending outward from the hub (41) in a radial direction of a central axis of the output shaft (31); a plurality of blades (43) extending from the main plate (42) to one side in the axial direction of the output shaft (31); and a side plate (44) joined to an end portion of each of the plurality of blades (43) facing the one side in the axial direction of the output shaft (31), wherein a weight of the main plate (42) is greater than a weight of the side plate (44); and the main plate (42) and the side plate (44) are both inclined to another side opposite to the one side in the axial direction of the output shaft (31), with the main plate (42) and the side plate (44) approaching an outer side in the radial direction. [2] Centrifugal blower according to claim 1, wherein a plate thickness of the main plate (42) is greater than a plate thickness of the side plate (44). [3] The centrifugal blower according to claim 1 or 2, wherein a length (h2) axially measured from a position of a connection between the hub (41) and the output shaft (31) to one end of the fan (4) facing the other side in the axial direction of the output shaft (31) is equal to or greater than one half of a length (h1) axially measured from another end of the fan (4) facing the one side in the axial direction of the output shaft (31) to the end of the fan (4) facing the other side in the axial direction of the output shaft (31). [4] Centrifugal blower according to one of claims 1 to 3, wherein the main plate (42) has: a first slope portion (42a) having an inclination gradient inclined toward the other side in the axial direction of the output shaft (31) with the first slope portion (42a) approaching the outer side in the radial direction, the inclination gradient of the first slope portion (42a) being within a first range, and a second slope portion (42b) placed on the outer side relative to the first slope portion (42a) in the radial direction and having an inclination gradient inclined toward the other side in the axial direction of the output shaft (31) as the second slope portion (42b) approaches the outer side in the radial direction, the inclination gradient of the second slope portion (42b) being within a second range different from the first range. [5] Centrifugal fan according to claim 4, wherein the first region is steeper than the second region. [6] Centrifugal blower according to claim 4 or 5, wherein a plate thickness of the second slope portion (42b) is greater than a plate thickness of the first slope portion (42a). [7] Centrifugal blower according to one of claims 4 to 6, wherein: the main plate (42) has an outer peripheral end portion (42c) located at an outermost periphery of the main plate (42) on the outer side relative to the second slope portion (42b) in the radial direction; and a plate thickness of the outer peripheral end portion (42c) is smaller than a plate thickness of the second bevel portion (42b). [8] Centrifugal blower according to one of claims 4 to 7, wherein: the side plate (44) is made of resin; and the second slope portion (42b) has a metal portion made of metal and a resin portion made of resin and surrounding the metal portion. [9] Centrifugal blower according to one of claims 1 to 8, wherein at least one blade of the plurality of blades (43) satisfies that a radius of curvature of a corner (R1a, R1b) at a joint between the at least one blade and the main plate (42) is larger than a radius of curvature of a corner (R2a, R2b) at a joint between the at least one blade and the side plate (44). [10] A centrifugal fan according to claim 9, wherein the radius of curvature of the corner (R1a, R1b) at the joint between the at least one blade and the main plate (42) increases towards the outer side in the radial direction. [11] A centrifugal blower according to any one of claims 1 to 10, wherein at least one blade of the plurality of blades (43) satisfies that a plate thickness of a portion of the at least one blade that is closer to the main plate (42) than to the side plate (44) is greater than a plate thickness of another portion of the at least one blade that is closer to the side plate (44) than to the main plate (42). [12] A centrifugal blower according to any one of claims 1 to 11, wherein the main plate (42) has at least one rib (42d, 42e, 42f) projecting from a surface of the main plate (42) opposite to the side plate (44) to the other side in the axial direction of the output shaft (31). [13] A centrifugal blower according to claim 12, wherein the at least one rib (42d, 42e, 42f) is formed in a star shape which is star-shaped with respect to the central axis of the output shaft (31), or in an annular shape surrounding the output shaft (31), or in a combination of the star shape and the annular shape. [14] A centrifugal fan according to claim 12, wherein the at least one rib (42d, 42e, 42f) is formed in a vane shape. [15] A centrifugal blower according to any one of claims 1 to 14, wherein the main plate (42) is made of a material having a mass density higher than a mass density of a material of the side plate (44). [16] Centrifugal blower according to one of claims 1 to 15, wherein the side plate (44) has a tubular portion (44b) surrounding the output shaft (31) and forming an intake port; and a front edge (43a), which is an end portion facing the output shaft (31), of at least one or all of the plurality of blades (43) has an end portion facing one side in the axial direction of the output shaft (31), wherein on the one side in the axial direction relative to an end of the tubular portion (44b) facing the other side in the axial direction of the output shaft (31), the one end portion of the front edge (43a) is joined to a surface of the tubular portion (44b) facing the output shaft (31).

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