Centrifugal fan and fixing method

Abstract

This centrifugal fan (1) is provided with: a first section (9) provided to a rotor (5); and a second section provided to a fan (3) and having a coefficient of linear expansion greater than that of the first section (9). The first section (9) comprises: a top surface (22) having a flat surface (22a); and a first cylindrical portion (23). The second section comprises: a main surface (34) that is located in one axial direction (C1) from the top surface (22): a second cylindrical portion (35) that has an inner cylindrical surface (35f) that faces an outer cylindrical surface (23f) of the first cylindrical portion (23) with a clearance (S) therebetween; and an annular rib (38) and a plurality of auxiliary ribs (39) that are provided protruding in a second axial direction (C2) from the main surface (34). An adhesive section (40) formed from an adhesive is provided between the flat surface (22a) and an annular end surface (38a) of the annular rib (38) and each of end surfaces (39a) of the plurality of auxiliary ribs (39) that face the flat surface (22a).

Description

Centrifugal Fan and Fixing Method

[0001] This case relates to a centrifugal fan and a fixing method for fixing a fan part to a rotor of the centrifugal fan.

[0002] The centrifugal fan includes a fan part having a plurality of blades and a motor part that is a drive source for the fan part. As the fan part rotates, it sends out the fluid inhaled from the vicinity of the rotation center to the outside in the radial direction of the fan part. Conventionally, in a centrifugal fan, by fixing the fan part to the rotor of the motor part, the rotor and the fan part are integrally rotated. For example, in Patent Document 1, a centrifugal fan is disclosed in which the outer peripheral surface of a metal rotor holder (rotor) provided on a motor (motor part) and the inner peripheral surface of the blade support part of a resin impeller (fan part) are fixed with an adhesive.

[0003] Japanese Patent Application Laid-Open No. 2019-116848

[0004] However, when the outer peripheral surface of the rotor holder and the inner peripheral surface of the blade support part of the fan part are adhesively fixed as in Patent Document 1, depending on the usage environment of the centrifugal fan, a shift in the center of gravity position due to thermal deformation may occur. Here, the thermal deformation means that as the temperature and temperature change around the centrifugal fan, the fan part of the centrifugal fan and the fixing member (rotor holder in Patent Document 1) to which the fan part is fixed each change in dimension. The fan part and the fixing member are often formed of different materials. For example, as in Patent Document 1, the fan part may be made of resin and the fixing member may be made of metal. In this way, when the fan part is formed of a material with a larger linear expansion coefficient than the fixing member, the amount of thermal deformation of the fan part becomes larger than the amount of thermal deformation of the fixing member, so the center of gravity position of the fan part relative to the fixing member may shift from the position before thermal deformation (initially). If a shift occurs in the center of gravity position of the fan part, it may have an adverse effect on the fan balance, and vibration and noise may occur during the operation of the centrifugal fan. Therefore, in order to avoid the shift in the center of gravity position of the fan part relative to the fixing member, it is conceivable to change the adhesion location of the fan part to the fixing member. However, in this case, ensuring the adhesion strength becomes an issue.

[0005] The centrifugal fan and fixing method described in this invention were devised in view of these problems, and one of its objectives is to ensure the adhesive strength of the fan portion to the rotor while suppressing the shift in the center of gravity due to thermal deformation. In addition to this objective, another objective of this invention is to achieve effects and advantages that cannot be obtained by conventional techniques, which are derived from the various configurations shown in the embodiments for carrying out the invention described later.

[0006] The disclosed centrifugal fan and fixing method can be implemented in the manner (application example) disclosed below, and solve at least some of the above problems.

[0007] The disclosed centrifugal fan comprises a first portion provided on a rotor that rotates integrally with a shaft, and a second portion provided on a fan portion fixed to the rotor and having a plurality of blades, and having a larger coefficient of linear expansion than the first portion. The first portion has a top surface portion that extends radially outward from a first hole through which the shaft is inserted and has a plane facing in the first axis direction among the axial directions of the shaft, and a cylindrical first cylindrical portion that extends from the radially outward end of the top surface portion in the second axis direction opposite to the first axis direction. The second portion includes a main surface portion located in the first axial direction from the top surface portion and extending radially outward from a second hole through which the shaft is inserted; an annular rib portion projecting from the main surface portion in the second axial direction and having an annular end face facing the plane; a plurality of auxiliary rib portions projecting from the main surface portion in the second axial direction and extending radially from the annular rib portion and having end faces facing the plane; and a cylindrical second cylindrical portion extending in the second axial direction from the radially outward end of the main surface portion and having an inner cylindrical surface facing the outer cylindrical surface of the first cylindrical portion with a clearance between them. An adhesive portion formed by adhesive is provided between the annular end face of the annular rib portion and the end faces of the plurality of auxiliary rib portions and the plane.

[0008] The disclosed fixing method is a fixing method for fixing a second portion, which is provided on a fan portion having a plurality of blades and having a larger coefficient of linear expansion than the first portion, to a first portion provided on the rotor of a motor portion having a rotor that rotates integrally with a shaft and a stator arranged opposite to the rotor. The first portion is provided with a top surface portion that extends radially outward from a first hole for shaft insertion and has a plane facing in the first axis direction, and a first cylindrical portion that extends from the radially outward end of the top surface portion in the second axis direction opposite to the first axis direction. The second portion is provided with a main surface portion that extends radially outward from a second hole for shaft insertion, an annular rib portion that protrudes from the main surface portion and has an annular end face, a plurality of auxiliary rib portions that protrude from the main surface portion in the same direction as the annular rib portion and extend radially from the annular rib portion and have end faces facing in the same direction as the annular end face, and a second cylindrical portion that extends from the radially outward end of the main surface portion in the same direction as the annular rib portion. The fixing method comprises: a first step of applying adhesive to the annular end face, or applying adhesive to a location on the plane that faces the annular end face when the main surface of the second part is positioned on the first axial side of the top surface of the part; a second step of positioning the main surface of the second part on the first axial side of the top surface of the part, so that the annular end face and the end face face each other on the plane; and a third step of positioning the inner surface of the second cylindrical part facing the outer surface of the first cylindrical part with a clearance between them, and spreading the adhesive between the annular end face and the plane, and between the end face and the plane.

[0009] According to the disclosed centrifugal fan and fixing method, it is possible to ensure the adhesive strength of the fan portion to the rotor while suppressing the shift in the center of gravity due to thermal deformation.

[0010] This is an axial cross-sectional view of a centrifugal fan according to an embodiment. This is a perspective view of the rotor yoke provided on the rotor of the motor section of the centrifugal fan in Figure 1. This is a half-axial cross-sectional view of the bladed main plate provided on the fan section of the centrifugal fan in Figure 1. This is a perspective view of the bladed main plate in Figure 3 from the second axial direction. This is an enlarged view of section X in Figure 1. This is a perspective view of the intermediate planar portion and inclined portion of the rotor yoke and the annular rib portion and a plurality of auxiliary rib portions of the bladed main plate in the centrifugal fan in Figure 1, viewed from the radially outward and first axial direction side (direction of arrow Y in Figure 5).

[0011] The centrifugal fan and fixing method as embodiments will be described with reference to the drawings. The embodiments shown below are merely illustrative, and there is no intention to exclude various modifications and applications of techniques not explicitly shown in the embodiments below. Each component of these embodiments can be modified in various ways without departing from their spirit.

[0012] [1. Configuration] Figure 1 is an axial cross-sectional view of the centrifugal fan 1 of this embodiment. As shown in Figure 1, the centrifugal fan 1 comprises a motor unit 2 as a drive source and a fan unit 3 driven by the motor unit 2. The centrifugal fan 1 is configured such that the motor unit 2 and the fan unit 3 are housed in a housing 10 that forms the outer casing of the centrifugal fan 1. The motor unit 2 has a shaft 4, a rotor 5 that rotates integrally with the shaft 4, and a stator 6 that is positioned opposite the rotor 5. The fan unit 3 is attached to the rotor 5 of the motor unit 2 on one side of the axial direction of the shaft 4 (the first axial direction C1 side, which will be described later), and is fixed to the rotor 5 with adhesive, so that it rotates integrally with the shaft 4 and the rotor 5. The centrifugal fan 1 may be used, for example, as a ventilation fan attached to the seat of a vehicle.

[0013] Hereinafter, the state in which the fan unit 3 is attached to and fixed to the rotor 5 of the motor unit 2 will be referred to as the fixed state. The state before the fixed state will be referred to as the pre-fixed state. Of the pre-fixed states, the state in which the fan unit 3 is attached to one side of the rotor 5 in the axial direction (the fan unit 3 is placed on one side in the axial direction) will be referred to as the attached state, and the state before the attached state (the state in which the fan unit 3 and rotor 5 are separated) will be referred to as the pre-attached state. In the centrifugal fan 1, the adhesive applied to the fan unit 3 in the pre-attached state spreads out between the fan unit 3 and the rotor 5 when the attached state is reached, and hardens, thereby achieving the fixed state. The fan unit 3 is fixed to the rotor 5 by adhesive bonding 40 (see Figures 5 and 6) formed by the hardening of the adhesive, and rotates integrally with the shaft 4 and rotor 5. In the following description, unless otherwise specified, the centrifugal fan 1 will be assumed to be in the fixed state.

[0014] Furthermore, the direction in which the shaft 4 extends (the direction of the axis C of the shaft 4) is referred to as the axial direction. Of the axial directions, the direction in which the fan unit 3 is attached to the motor unit 2 is called the first axial direction C1, and the direction opposite to the first axial direction C1 is called the second axial direction C2. Also, the direction perpendicular to the axial direction and away from the axis C of the shaft 4 is called the radially outward direction, and the direction in the same direction and toward the axis C is called the radially inward direction; when there is no distinction between inside and outside, it is simply called the radial direction. The direction perpendicular to the axial direction and revolving around the axis C is called the circumferential direction.

[0015] As described above, the motor unit 2 has a shaft 4, a rotor 5, and a stator 6. The motor unit 2 in this embodiment is an outer rotor type motor, and as shown in Figure 1, the stator 6 is arranged radially inward of the rotor 5. The shaft 4 extends, for example, from the second axial direction C2 side of the stator 6 to the first axial direction C1 side of the fan unit 3. The end of the shaft 4 on the second axial direction C2 side and the axial intermediate portion may be rotatably supported by a bearing 11. The bearing 11 is held in a cylindrical bearing holder 12 fixed to the housing 10.

[0016] The stator 6 comprises an annular stator core 7 formed by laminating multiple steel plates of the same shape. The stator 6 may be provided with a coil (not shown) wound around the stator core 7 via an insulator. The stator core 7 is fixed to the housing 10 in a non-rotatable manner by being fitted onto and fixed to the bearing holder 12 with the lamination direction of the steel plates aligned axially at its center.

[0017] The rotor 5 comprises a magnet 8 and a rotor yoke 9, which are arranged radially opposite to the stator core 7. The magnet 8 is made of, for example, a long rectangular rubber magnet, and is formed by joining both ends of the rubber magnet to form an annular shape with an inner diameter larger than the outer diameter of the stator core 7. The magnet 8 is fixed to the rotor yoke 9 and is arranged radially outside the stator core 7 with a gap between them.

[0018] The rotor yoke 9 is a component that fixes the magnet 8 so that it cannot rotate relative to the shaft 4 and suppresses leakage of magnetic field lines from the magnet 8, and is made of, for example, a magnetic steel plate (metal). The rotor yoke 9 is, for example, a bottomed cylindrical (cup-shaped) that opens toward the second axial direction C2 and covers the stator 6 from the first axial direction C1 side. The rotor yoke 9 is provided with a first hole 21 for inserting the shaft 4, a cylindrical first cylindrical portion 23 located radially outside the stator core 7, and a top surface portion 22 connecting the first hole 21 and the first cylindrical portion 23.

[0019] The first hole portion 21 is the part that forms the through hole 21h (see Figure 2) through which the shaft 4 is inserted, and is, for example, cylindrical in shape concentric with the axis C. The rotor yoke 9 is fixed so as not to rotate relative to the shaft 4 when the shaft 4 is inserted into the through hole 21h and the first hole portion 21 is press-fitted and fixed to the shaft 4.

[0020] The first cylindrical portion 23 is a part for fixing the magnet 8, and as shown in Figure 1, it is provided so as to surround the stator core 7 from the radially outer side. The first cylindrical portion 23 is, for example, a cylindrical shape concentric with the axis C and extends in the axial direction. As shown in Figures 2 and 5, the first cylindrical portion 23 has an inner cylindrical surface 23g (see Figure 5) facing radially inward and an outer cylindrical surface 23f facing radially outward. The diameter of the inner cylindrical surface 23g is set to be larger than the outer diameter of the stator core 7. The magnet 8 is fixed to the inner cylindrical surface 23g so as not to rotate relative to the shaft 4.

[0021] As shown in Figure 1, the top surface portion 22 is the part that covers the magnet 8 and stator 6 from the first axial direction C1 side. The top surface portion 22 extends radially outward from the end of the first hole portion 21 on the second axial direction C2 side, as shown in Figures 1 and 2, and is connected to the end of the first cylindrical portion 23 on the first axial direction C1 side. Hereinafter, "extending toward" is not limited to extending in a direction that coincides with (is parallel to) the reference direction (e.g., the radial direction), but also includes extending in a direction that is inclined with respect to the reference direction. The same applies hereafter when "extending toward" is explained.

[0022] The top surface portion 22 may be composed of a combination of flat portions, curved portions, and stepped or tapered surfaces (parts). The top surface portion 22 exemplified here comprises an inner flat portion 24, a stepped portion 25, an intermediate flat portion 26, an inclined portion 27, and an outer flat portion 28, with these portions 24 to 28 arranged in this order from the radially inner to the radially outer. As shown in Figure 2, the inner flat portion 24, the intermediate flat portion 26, the inclined portion 27, and the outer flat portion 28 all form annular shapes concentric with axis C when viewed from the axial direction. The stepped portion 25 is cylindrical and concentric with axis C, and extends in the axial direction.

[0023] As shown in Figure 1, the inner planar portion 24 is connected to the second axial direction C2 side of the first hole portion 21 and extends radially outward. The stepped portion 25 is connected to the radially outward side of the inner planar portion 24 and extends in the second axial direction C2. The intermediate planar portion 26 is connected to the second axial direction C2 side of the stepped portion 25 and extends radially outward. The inclined portion 27 is connected to the radially outward side of the intermediate planar portion 26 and extends radially outward and diagonally towards the second axial direction C2. The outer planar portion 28 is connected to the radially outward side of the inclined portion 27 and extends radially outward. The radially outward end of the outer planar portion 28 is connected to the end of the first cylindrical portion 23 on the first axial direction C1 side. The top surface portion 22, as a whole, extends radially outward and towards the second axial direction C2 from the first hole portion 21 by these portions 24 to 28. In this specification, "connection" means that two parts are linked together, and does not mean connecting (attaching) two parts that are provided separately.

[0024] In this embodiment, the fan section 3 is adhesively fixed to the rotor yoke 9. In other words, the rotor yoke 9 corresponds to the "first part" as described in the claims. The specific configuration will be described later, but the fan section 3 is adhesively fixed to the surface of the intermediate flat portion 26 of the top surface 22 that faces the first axis direction C1 (see Figures 2, 5, and 6), where the rib portion 36 provided on the fan section 3 is adhesively fixed. Hereinafter, this surface will be referred to as the adhesive surface 22a (flat surface).

[0025] The fan section 3 is an impeller that draws in fluid from the radially inner side and sends it out radially outer, and as shown in Figure 3, it has a plurality of blades 31 that are erected in the axial direction. The plurality of blades 31 are arranged at equal intervals in the circumferential direction with respect to the axis C. The fan section 3 may be provided with a main plate section 32 that supports the ends of the plurality of blades 31 on the second axial direction C2 side.

[0026] As shown in Figure 1, the fan section 3 may include a bladed main plate 13 in which a plurality of blades 31 and a main plate 32 are integrally molded, and a shroud 14. The fan section 3 is configured such that, for example, the shroud 14 is attached and fixed to the bladed main plate 13 on the first axial direction C1 side. The bladed main plate 13 and the shroud 14 are separately molded from a resin having a higher coefficient of thermal expansion than the rotor yoke 9, and then assembled.

[0027] The shroud 14 is a plate material fixed to the ends of the multiple blade portions 31 on the first axial direction C1 side, and has an annular shape with air passage holes 14h for intake air passages formed on the radially inward side. The shroud 14 is fixed to the main plate 13 with blades, for example, by ultrasonic welding.

[0028] The bladed main plate 13 comprises the blade portion 31 and the main plate portion 32 described above. In this embodiment, the main plate portion 32 is provided radially outward from the first cylindrical portion 23 of the rotor yoke 9. As shown in Figures 1, 3, and 4, for example, the main plate portion 32 has a flat plate shape with uniform axial dimensions (thickness, plate thickness) and forms an annular shape concentric with the axis C when viewed from the axial direction.

[0029] The winged main plate 13 further comprises a second hole portion 33, a main surface portion 34, a second cylindrical portion 35, and a rib portion 36. These portions 33 to 36 are provided radially inward of the main plate portion 32. In this embodiment, these portions 33 to 36 correspond to the "second portion" described in the claims.

[0030] The second hole 33 is a hole for inserting the shaft 4. The second hole 33 is the part that forms the through hole 33h (see Figures 3 and 4) through which the shaft 4 is inserted, and is, for example, cylindrical in shape concentric with the axis C. The inner diameter of the second hole 33 is set to be, for example, the same as the outer diameter of the shaft 4, or slightly larger than the outer diameter of the shaft 4. The second hole 33 may or may not be fixed to the shaft 4.

[0031] The main surface portion 34 is a part that extends radially outward from the second hole portion 33, and has a plate-like shape with substantially uniform dimensions (thickness, plate thickness) in the direction perpendicular to the extension direction, and forms an annular shape concentric with the axis C when viewed from the axial direction. The main surface portion 34 extends radially outward and toward the second axial direction C2 (diagonally) from the second hole portion 33, corresponding to the extension direction of the top surface portion 22 of the rotor yoke 9, and connects to the radially inward side of the main plate portion 32. As a result, the main surface portion 34 covers the rotor yoke 9 from the first axial direction C1 side. In other words, the main surface portion 34 extends diagonally with respect to the axial direction so as to form a curve that protrudes toward the first axial direction C1 side when viewed from the radial direction. With such a main surface portion 34, fluid drawn in from the first axial direction C1 side is easily guided toward the second axial direction C2 side and radially outward along the extension direction of the main surface portion 34.

[0032] As shown in Figures 1 and 3, the ends of the multiple blade portions 31 on the second axial direction C2 side may be connected not only to the main plate portion 32 but also to the main surface portion 34. In other words, the main surface portion 34 may perform the function of the main plate portion 32 together with the main plate portion 32 (the function of supporting the ends of the multiple blade portions 31 on the second axial direction C2 side). Preferably, the thickness of the main surface portion 34 is the same as the thickness of the main plate portion 32.

[0033] The second cylindrical portion 35 is a cylindrical part that extends in the second axial direction C2 from the radially outer end of the main surface portion 34 (i.e., the boundary position between the main plate portion 32 and the main surface portion 34). For example, as shown in Figure 4, the inner cylindrical surface 35f facing radially inward and the outer cylindrical surface facing radially outward each have a cylindrical shape with a uniform diameter in the axial direction and are concentric with the axis C. As shown in Figure 1, the second cylindrical portion 35 extends to a position where it overlaps with the first cylindrical portion 23 of the rotor yoke 9 when viewed from the radial direction, and surrounds the first cylindrical portion 23 of the rotor yoke 9 from the radially outside. As shown in Figure 5, the inner cylindrical surface 35f of the second cylindrical portion 35 faces the outer cylindrical surface 23f of the first cylindrical portion 23.

[0034] As shown in Figures 1, 3, and 4, the radially inner portion of the main plate portion 32 of the winged main plate 13 forms a bottomed cylindrical shape (cup shape) that opens toward the second axis direction C2, due to the second hole portion 33, the main surface portion 34, and the second cylindrical portion 35. Hereinafter, these portions 33 to 35 will be collectively referred to as the cup portion 37.

[0035] The rib portion 36 is a part that protrudes from the main surface portion 34 in the second axial direction C2 and reinforces the main surface portion 34. In this embodiment, as described above, the rib portion 36 is bonded and fixed to the adhesive surface 22a of the rotor yoke 9. For this reason, when viewed from the axial direction, at least a part of the rib portion 36 is positioned so as to overlap at least a part of the adhesive surface 22a. Preferably, as shown in Figure 1, the rib portion 36 is provided at a position radially inward from the second cylindrical portion 35 and radially outward from the second hole portion 33.

[0036] Here, if the main plate 13 with blades (fan section 3) having the cup section 37 described above is made of a material with a larger coefficient of linear expansion than the rotor yoke 9 to which it is fixed, the fan section 3 may undergo greater thermal deformation than the rotor yoke 9 when exposed to an environment with drastic temperature changes around it. The inventors of this invention have found that the thermal deformation of the cup section 37 described above has two tendencies: one in which the second cylindrical section 35 deforms to a reduced diameter, with the boundary position between the main surface section 34 and the second cylindrical section 35 as the starting point, and another in which the main surface section 34 deforms to float upward toward the first axial direction C1.

[0037] Furthermore, we found that the latter of these deformation tendencies (i.e., the lifting deformation of the main surface portion 34) is caused by a shift in the center of gravity of the fan portion 3. In addition, we found that in conventional centrifugal fans where adhesive is provided between the rotor cylinder portion and the fan cylinder portion, even if the fan cylinder portion attempts to deform in diameter due to temperature changes, this deformation is inhibited by the adhesive, and the amount by which the deformation of the cylinder portion is inhibited can be replaced by the lifting deformation of the top surface portion of the fan portion (the amount of lifting deformation increases compared to the case where the deformation of the cylinder portion is not inhibited).

[0038] Therefore, in the centrifugal fan 1 of this invention, as shown in Figure 5, a clearance S is provided between the first cylindrical portion 23 and the second cylindrical portion 35 so as not to hinder the second cylindrical portion 35 from undergoing diameter reduction deformation. Furthermore, in order to leave this clearance S as space, the bonding location was changed, and the top surface portion 22 and the rib portion 36 were bonded and fixed together. As a result, the diameter reduction deformation of the second cylindrical portion 35 is permitted, and this is not replaced by the lifting deformation of the main surface portion 34, thus preventing the force that causes the diameter reduction deformation of the second cylindrical portion 35 from being converted into a force that deforms the main surface portion 34. Thus, the lifting deformation of the main surface portion 34 is suppressed, and the shift in the center of gravity position of the fan portion 3 is suppressed.

[0039] The clearance S is a cylindrical space (gap) with a small radial dimension formed between the outer surface 23f of the first cylindrical portion 23 and the inner surface 35f of the second cylindrical portion 35. The radial dimension of the clearance S is set to such a size that, for example, the second cylindrical portion 35 does not come into contact with the first cylindrical portion 23 even if the second cylindrical portion 35 undergoes a reduction in diameter deformation. The diameter of the inner surface 35f of the second cylindrical portion 35 is set to such a size that such a clearance S can be formed between it and the outer surface 23f of the first cylindrical portion 23.

[0040] In this embodiment, the portion at the boundary between the plate-shaped main surface portion 34 and the second cylindrical portion 35 having a uniform diameter in the axial direction may have a relatively larger thickness than other portions of the bladed main plate 13, as shown in Figure 5. Hereinafter, "larger thickness" means that the material (resin) of the fan portion 3 is concentrated where the various parts constituting the fan portion 3 converge. Hereinafter, this portion will be referred to as the "thick portion 35a".

[0041] In this embodiment, as described above, the ends of the multiple blade portions 31 on the second axial direction C2 side are connected to the main surface portion 34, and the radially inner end of the main plate portion 32 is connected to the radially outer end of the main surface portion 34. Therefore, as shown in Figure 3, the thickness of the thickened portion 35a can be further increased at the point where the root portion of the blade portion 31 in the second axial direction C2 and the radially inner root portion of the main plate portion 32 converge.

[0042] By forming such a thick portion 35a, in the fan portion 3, the above-described tendency of thermal deformation of the cup portion 37 becomes more likely to occur. However, since the diameter reduction deformation of the second cylindrical portion 35 starting from the thick portion 35a is allowed by the clearance S, the deformation of the main surface portion 34 is suppressed. In the present embodiment, it can also be said that the above-described rib portion 36 is provided at a position separated from the second cylindrical portion 35, that is, at a position separated from the thick portion 35a.

[0043] Furthermore, the centrifugal fan 1 of the present case is provided with a configuration for increasing the adhesive strength of the fan portion 3 with respect to the rotor yoke 9. Specifically, as shown in FIGS. 4 and 5, as the rib portion 36, an annular rib portion 38 and a plurality of auxiliary rib portions 39 protruding from the main surface portion 34 in the second axial direction C2 are provided. In the centrifugal fan 1, the adhesive applied to the annular end surface 38a on the second axial direction C2 side of the annular rib portion 38 spreads when it is in the mounted state, so that not only between the annular end surface 38a and the adhesive surface 22a, but also between the end surfaces 39a on the second axial direction C2 side of the plurality of auxiliary rib portions 39 and the adhesive surface 22a. In other words, it can also be expressed that the adhesive applied to the annular end surface 38a of the annular rib portion 38 entangles the adhesive with the annular rib portion 38 and the plurality of auxiliary rib portions 39 when it is in the mounted state. The centrifugal fan 1 is fixed to the adhesive surface 22a by the adhesive portion 40 (see FIG. 5) formed by the curing of the adhesive, and the rib portion 36 is fixed, thereby ensuring the adhesive strength of the fan portion 3 with respect to the rotor yoke 9.

[0044] The annular rib portion 38 is a portion protruding from the main surface portion 34 in the second axial direction C2 and has an annular end surface 38a facing the second axial direction C2. The annular end surface 38a is an annular plane that makes a full circle around the axis C when viewed from the second axial direction C2 and faces the adhesive surface 22a. The annular rib portion 38 may be, for example, a cylindrical shape having an annular end surface 38a in a circular ring shape concentric with the axis C, an inner peripheral surface 38b facing the radially inner side, and an outer peripheral surface 38c facing the radially outer side, as shown in FIG. 4.

[0045] Multiple auxiliary rib portions 39 protrude from the main surface portion 34 in the same direction as the annular rib portion 38 (i.e., the second axial direction C2) and extend radially from the annular rib portion 38. In this embodiment, the multiple auxiliary rib portions 39 are provided on the radially outer side of the annular rib portion 38 and extend radially outward from the annular rib portion 38. The multiple auxiliary rib portions 39 may all have the same shape and be provided at equal intervals, spaced apart from each other in the circumferential direction. Here, twelve auxiliary rib portions 39 of the same shape are provided at equal intervals, spaced apart from each other, on the radially outer side of the annular rib portion 38. Note that in Figure 4, only one of the twelve auxiliary rib portions 39 is labeled with a reference numeral.

[0046] Each auxiliary rib portion 39 has an end face 39a facing the second axial direction C2. Each end face 39a faces the adhesive surface 22a. Each auxiliary rib portion 39 is, for example, a roughly triangular prism shape having a rectangular end face 39a and a pair of triangular side faces 39d facing opposite directions in the circumferential direction. Hereinafter, the end face 39a will also be referred to as the rectangular end face 39a. As shown in Figures 4 and 5, each auxiliary rib portion 39 extends in the axial direction to the same position as the annular rib portion 38. The annular end face 38a of the annular rib portion 38 and the rectangular end face 39a of each auxiliary rib portion 39 thus form a single continuous plane (a plane perpendicular to the axial direction).

[0047] The circumferential width of the auxiliary rib portion 39 is preferably set to be the same as the radial width of the annular rib portion 38. More preferably, the radial width of the annular rib portion 38 and the circumferential width of the auxiliary rib portion 39 are such that a bonding area sufficient to obtain adhesive strength that satisfies the specifications of the centrifugal fan 1 is secured, and it is preferable that they be set to be slightly larger than the thickness of the main surface portion 34 and the main plate portion 32. This suppresses distortion of the shape caused by the difference in curing time resulting from the difference in the amount of resin during the molding of the bladed main plate 13.

[0048] Among some of the plurality of auxiliary rib portions 39, as shown in FIGS. 3 and 4, a convex portion 50 protruding from the rectangular end face 39a in the second axial direction C2 may be provided. The convex portion 50 is a portion provided to form a space (gap) for interposing an adhesive portion 40 between the annular end face 38a, the rectangular end face 39a, and the adhesive surface 22a, and abuts (contacts) against the adhesive surface 22a in the mounted state as shown in FIG. 6. The number of the convex portions 50 is preferably three or more. In this case, it is preferable that the three or more convex portions 50 are provided at equal intervals spaced apart from each other in the circumferential direction, and it is preferable that the protrusion amounts with respect to the rectangular end face 39a are all set to be equal.

[0049] Here, as shown in FIG. 4, among the twelve auxiliary rib portions 39, the convex portion 50 is provided on each of the three auxiliary rib portions 39 provided every three. When such a convex portion 50 abuts against the adhesive surface 22a of the rotor yoke 9, the annular end face 38a and the rectangular end face 39a are arranged in parallel with the adhesive surface 22a. Therefore, the axial width of the gap (space) formed between the annular end face 38a, the rectangular end face 39a, and the adhesive surface 22a becomes uniform, and the adhesion balance of the fan portion 3 with respect to the rotor 5 is improved.

[0050] The protrusion amount of the convex portion 50 with respect to the rectangular end face 39a is preferably set to be equal to the optimum film thickness of the adhesive. The optimum film thickness here means the film thickness when the adhesive strength by the adhesive exhibits a strength capable of withstanding the load assumed when used as the centrifugal fan 1. The optimum film thickness may be determined based on verification of the relationship between the film thickness and the adhesive strength through experiments, simulations, etc. for an adhesive that satisfies the specifications of the centrifugal fan 1, for example.

[0051] As described above, the adhesive portion 40 is a portion formed by the adhesive applied to the annular end face 38a in the state before attachment spreading and curing when it becomes the attached state. The adhesive portion 40 is provided at least between the annular end face 38a and the adhesive surface 22a and between the rectangular end face 39a and the adhesive surface

[0052] 22a.

[0052] In this embodiment, as shown in Figures 5 and 6, the adhesive portion 40 is provided not only between the annular end face 38a and the rectangular end face 39a and the adhesive surface 22a, but also on the radially inner side of the annular rib portion 38, the radially outer side of the annular rib portion 38, and on both sides of the auxiliary rib portion 39 in the circumferential direction. That is, the applied adhesive spreads from the adhesive surface 22a to the inner circumferential surface 38b of the annular rib portion 38, the outer circumferential surface 38c of the annular rib portion 38, and the pair of side surfaces 39d of the auxiliary rib portion 39, and adhesive portions 40 are also provided in these areas. As a result, not only the annular end face 38a and the rectangular end face 39a, but also the inner circumferential surface 38b, the outer circumferential surface 38c, and the side surfaces 39d are bonded and fixed to the adhesive surface 22a, further increasing the adhesive strength of the fan portion 3 to the rotor 5. In particular, the adhesive strength in the circumferential direction (i.e., the rotation direction of the fan portion 3) is further increased.

[0053] Furthermore, in order to form such an adhesive portion 40, it is preferable that a larger amount of adhesive is applied to the annular end face 38a in the pre-installation state than the volume of the gap formed between the adhesive surface 22a and the annular end face 38a in the installed state. More preferably, a larger amount of adhesive (hereinafter referred to as "excessive amount") is applied to the annular end face 38a in the pre-installation state than the volume of the gap formed between the adhesive surface 22a and the annular end face 38a and the rectangular end face 39a in the installed state.

[0054] [2. Fixing Method] The fixing method (fixing procedure) for the fan section 3 (main plate with blades 13) to the rotor 5 (rotor yoke 9) of the centrifugal fan 1 described above will be explained below. This fixing method consists of three steps: the first step, the second step, and the third step.

[0055] First, in the first step, adhesive is applied to the annular end face 38a of the winged main plate 13 in its pre-installation state. In other words, the first step is the step of applying adhesive to the annular end face 38a. In the first step, for example, an excessive amount of adhesive is applied evenly to the entire annular end face 38a.

[0056] In the subsequent second step, the vane-equipped main plate 13, in its pre-installation state, is positioned concentrically with the rotor yoke 9 on the first axial direction C1 side of the rotor yoke 9. That is, the main surface portion 34 is positioned concentrically with the top surface portion 22 on the first axial direction C1 side of the top surface portion 22. As a result, the annular end surface 38a and the rectangular end surface 39a face the adhesive surface 22a. In short, the second step is to position the main surface portion 34 of the vane-equipped main plate 13 on the first axial direction C1 side of the top surface portion 22 of the rotor yoke 9, and to position the annular end surface 38a and the rectangular end surface 39a facing the adhesive surface 22a.

[0057] In the second step, for example, the end of the shaft 4 on the first axial direction C1 side, with the rotor yoke 9 press-fitted and fixed, is inserted into the second hole 33 of the main plate with blades 13. This causes the rotor yoke 9 and the main plate with blades 13 to be arranged coaxially (concentrically).

[0058] In the subsequent third step, the main plate with blades 13 is placed on the rotor yoke 9 on the first axial direction C1 side. The main plate with blades 13 is placed on the rotor yoke 9 on the first axial direction C1 side by being pushed in the second axial direction C2 side until, for example, the protrusion 50 abuts against the adhesive surface 22a. The centrifugal fan 1 is then mounted.

[0059] When the winged main plate 13 is placed on the rotor yoke 9, the second cylindrical portion 35 is positioned to surround the first cylindrical portion 23 from the radially outer side. As a result, as shown in Figure 5, the inner cylindrical surface 35f of the second cylindrical portion 35 is positioned opposite the outer cylindrical surface 23f of the first cylindrical portion 23 with a clearance S between them. Furthermore, when the winged main plate 13 is placed on the rotor yoke 9, the adhesive applied to the annular end surface 38a can no longer be contained in the gap between the annular end surface 38a and the adhesive surface 22a, and spreads (unfolds) not only between the annular end surface 38a and the adhesive surface 22a, but also between the rectangular end surface 39a and the adhesive surface 22a. In other words, the third step can be described as a step in which the inner cylindrical surface 35f of the second cylindrical portion 35 is positioned opposite the outer cylindrical surface 23f of the first cylindrical portion 23 with a clearance S between them, and the adhesive is unfolded between the annular end surface 38a and the rectangular end surface 39a and the adhesive surface 22a.

[0060] If an excessive amount of adhesive is applied to the annular end face 38a, the adhesive will spread (unfold) to the radially inner side of the annular rib portion 38, the radially outer side of the annular rib portion 38, and both sides of the auxiliary rib portion 39 in the circumferential direction. As shown in Figures 5 and 6, the unfolded adhesive will also come into contact with the inner circumferential surface 38b, the outer circumferential surface 38c, and the side surface 39d. The adhesive unfolded on each surface will harden over time and eventually form the aforementioned bonded portion 40. Furthermore, once the adhesive hardens, the centrifugal fan 1 will be fixed in place.

[0061] The shroud 14 may be fixed to the winged main plate 13 before the first, second, and third steps are performed, or after these steps are performed. The stator 6 may be fixed to the bearing holder 12 and the shaft 4 may be attached before the first, second, and third steps are performed, or after these steps are performed. The shaft 4 may be inserted into the first hole 21 and the second hole 33 after the first, second, and third steps are performed.

[0062] [3. Function and Effects] (1) In the centrifugal fan 1 described above, a clearance S is formed between the outer surface 23f of the first cylindrical portion 23 and the inner surface 35f of the second cylindrical portion 35. As a result, even if the centrifugal fan 1 is used in an environment with large temperature changes, the diameter reduction deformation of the second cylindrical portion 35 due to the temperature changes is permitted, and the lifting deformation of the main surface portion 34 caused by the inhibition of the diameter reduction deformation of the second cylindrical portion 35 can be suppressed. Therefore, the shift in the center of gravity of the fan portion 3 can be suppressed.

[0063] Furthermore, the centrifugal fan 1 described above is provided with an annular rib portion 38 and a plurality of auxiliary rib portions 39 as a rib portion 36 that is bonded and fixed to the rotor yoke 9 in place of the second cylindrical portion 35. In addition, in the centrifugal fan 1 described above, the bonded portion 40 formed by adhesive is interposed not only between the annular end face 38a and the bonded surface 22a, but also between each of the rectangular end faces 39a of the plurality of auxiliary rib portions 39 and the bonded surface 22a. This allows the fan portion 3 to be fixed to the rotor yoke 9 with higher adhesive strength than if only the annular end face 38a and the bonded surface 22a were bonded and fixed. Also, compared to a configuration that simply increases the radial width of the annular end face 38a to increase the bonding area, providing a plurality of auxiliary rib portions 39 that extend radially from the annular rib portion 38 to secure the bonding area contributes to reducing material costs and weight. In addition, if the fan portion 3 is made of resin, distortion of shape caused by differences in curing time due to differences in the amount of resin can also be suppressed. Therefore, the centrifugal fan 1 described above can effectively suppress the shift in the center of gravity due to thermal deformation while ensuring the adhesive strength of the fan section 3 to the rotor 5. Furthermore, since the auxiliary rib section 39 extends radially outward from the annular rib section 38, the flow of resin during molding is improved, and the finishing accuracy such as the flatness and parallelism of the fan section 3 can be improved.

[0064] (2) If the adhesive portion 40 is provided not only between the adhesive surface 22a and the annular end face 38a and the rectangular end face 39a, but also extends to the inner circumferential surface 38b and outer circumferential surface 38c of the annular rib portion 38 and the side surface 39d of the auxiliary rib portion 39, the adhesive strength of the fan portion 3 to the rotor 5 can be further increased. In particular, the adhesive strength in the circumferential direction (i.e., the rotation direction of the fan portion 3) can be further increased.

[0065] (3) When the main surface portion 34 extends radially outward from the second hole portion 33 and toward the second axis direction C2, the fluid drawn in from the first axis direction C1 can be smoothly pushed out along the main surface portion 34 toward the second axis direction C2 and radially outward. Therefore, the airflow efficiency of the fan portion 3 can be improved. In addition, since the fluid vortexing on the radially inner side of the fan portion 3 can be suppressed, noise from the fan portion 3 can also be reduced.

[0066] (4) When the main surface portion 34 extends radially outward from the second hole portion 33 and toward the second axial direction C2, if the auxiliary rib portion 39 is provided radially outward rather than radially inward of the annular rib portion 38, the amount of protrusion of the auxiliary rib portion 39 relative to the main surface portion 34 can be suppressed. Also, when the winged main plate 13 is made of resin, by suppressing the amount of protrusion of the auxiliary rib portion 39, distortion of the shape caused by the difference in curing time due to the difference in the amount of resin during molding can be suppressed.

[0067] (5) If the rib portion 36, which consists of an annular rib portion 38 and a plurality of auxiliary rib portions 39, is provided at a position separated from the second cylindrical portion 35 in the radial direction, the rib portion 36 fixed to the adhesive surface 22a can suppress the inhibition of the diameter reduction deformation of the second cylindrical portion 35. As a result, the force of the diameter reduction deformation of the second cylindrical portion 35 can be suppressed from being replaced by the lifting deformation of the main surface portion 34, and thus the shift in the center of gravity of the fan portion 3 can be effectively suppressed.

[0068] (6) If the rib portion 36 is provided at a position spaced apart from the second hole portion 33 in the radial direction, the amount of protrusion of the rib portion 36 from the main surface portion 34 which extends radially outward and toward the second axial direction C2 can be suppressed. Thus, the formability of the winged main plate 13 having the second hole portion 33, main surface portion 34, second cylindrical portion 35, and rib portion 36 can be improved. Furthermore, if the annular rib portion 38 is provided at a position spaced apart from the second hole portion 33, the area of ​​the annular end face 38a of the annular rib portion 38 is increased. As a result, the bonding area is increased and the bonding strength can be improved.

[0069] (7) When the bladed main plate 13 is made of resin, the bladed main plate 13 having the second hole portion 33, main surface portion 34, second cylindrical portion 35, and rib portion 36 can be easily molded from resin, which has higher moldability than metal. Also, by making the rotor yoke 9 from metal, which is less susceptible to thermal deformation than resin, thermal deformation of the rotor yoke 9 due to temperature changes can be suppressed. Therefore, the shift in the center of gravity of the fan portion 3 can be suppressed more effectively.

[0070] (8) In the fixing method described above, the fixing of the bladed main plate 13 to the rotor yoke 9 is completed simply by applying adhesive only to the annular end face 38a (first step), facing the bladed main plate 13 toward the rotor yoke 9 (second step), and placing the bladed main plate 13 on the rotor yoke 9 (third step). Therefore, a centrifugal fan 1 can be constructed in a simple manner in which the shift in the center of gravity of the fan section 3 is less likely to occur and the adhesive strength is maintained.

[0071] [4. Others] The configuration of the centrifugal fan 1 described above is just one example and is not limited to the above configuration. The fixing method described above is also just one example and is not limited to the above method. In the first step, adhesive may be applied to the rotor yoke 9. More specifically, in the first step, adhesive may be applied to the adhesive surface 22a of the rotor yoke 9 at the location that faces the annular end surface 38a when the main surface 34 is positioned on the first axial direction C1 side of the top surface 22.

[0072] The top surface portion 22 of the rotor yoke 9 does not have to be a surface portion that extends radially outward and toward the second axial direction C2; for example, it may simply be a surface portion that extends radially outward (perpendicular to the axial direction) from the first hole portion 21. The top surface portion 22 does not have to have multiple portions 24 to 28 with different extending directions.

[0073] The first cylindrical portion 23 only needs to extend in the second axial direction C2 from at least the radially outer end of the top surface portion 22, and does not need to be the part to which the magnet 8 is fixed, nor does it need to be the part that surrounds the stator core 7 from the radially outer side. In other words, in the centrifugal fan 1 described above, the rotor yoke 9 was provided as the "first part" described in the claim, but the "first part" described in the claim does not have to be the rotor yoke 9.

[0074] The rotor 5 may be provided with a part (component) that corresponds to the "first part" described in the claims, separate from the rotor yoke 9. This part does not have to be cup-shaped like the rotor yoke 9. Furthermore, the "first part" described in the claims only needs to be made of a material with a lower coefficient of thermal expansion than the "second part" described in the claims, and does not have to be made of metal. The motor unit 2 may also be an inner rotor type motor.

[0075] The annular end face 38a only needs to be an annular shape that encircles the axis C at least once, and may, for example, have a polygonal outer shape when viewed from the axial direction. The multiple auxiliary rib portions 39 do not all have to be the same shape, and may extend radially inward from the annular rib portion 38. The number of auxiliary rib portions 39 is not limited to twelve, but may be two or more. The end face 39a of the auxiliary rib portion 39 does not have to be rectangular. The protrusions 50 provided on the auxiliary rib portion 39 may be omitted.

[0076] The main surface portion 34 of the fan portion 3 does not have to be a surface portion that extends radially outward from the second hole portion 33 and toward the second axis direction C2; for example, it may simply be a surface portion that extends radially outward (perpendicular to the axis) from the second hole portion 33. The second cylindrical portion 35 is a cylindrical shape that extends in the second axis direction C2 from at least the radially outward end of the main surface portion 34 and has an inner cylindrical surface 35f that faces the outer cylindrical surface 23f of the first cylindrical portion 23 with a clearance S between them, but it does not have to be cylindrical. The second cylindrical portion 35 may be a cylindrical shape with an outer shape that is polygonal when viewed from the axis direction, for example. Similarly, the first cylindrical portion 23 may be a cylindrical shape with an outer shape that is polygonal when viewed from the axis direction.

[0077] The second hole portion 33, the main surface portion 34, the second cylindrical portion 35, and the rib portion 36 may be any part provided on the fan portion 3 having multiple blade portions 31, and may be a part (component) provided separately from the main plate with blades 13. In other words, the "second portion" described in the claim does not have to be a part of the main plate with blades 13. Also, the shroud 14 of the fan portion 3 may be omitted, and the blade portion 31 and the main plate portion 32 do not have to be integrally molded as the main plate with blades 13.

[0078] The "second part" described in the claim only needs to be made of a material with a higher coefficient of thermal expansion than the "first part" described in the claim, and does not have to be made of resin. The "first part" and the "second part" described in the claim may both be made of resin or metal, as long as the relationship of coefficients of thermal expansion is satisfied.

[0079] 1 Centrifugal fan 2 Motor section 3 Fan section 4 Shaft 5 Rotor 21 First hole section 22 Top surface section 22a Adhesion surface (flat surface) 23 First cylindrical section 23f Outer cylindrical surface 31 Blade section 33 Second hole section 34 Main surface section 35 Second cylindrical section 35f Inner cylindrical surface 38 Annular rib section 38a Annular end surface 38b Inner circumferential surface 38c Outer circumferential surface 39 Auxiliary rib section 39a Rectangular end surface (end surface) 39d Side surface 40 Adhesion section C1 First axial direction C2 Second axial direction S Clearance

Claims

1. The fan comprises a first portion provided on a rotor that rotates integrally with the shaft, and a second portion provided on a fan section fixed to the rotor and having a plurality of blades, the second portion having a larger coefficient of linear expansion than the first portion, the first portion having a top surface portion that extends radially outward from a first hole through which the shaft is inserted and has a plane facing in the first axis direction of the shaft's axial direction, and a cylindrical first cylindrical portion that extends from the radially outward end of the top surface portion in the second axis direction opposite to the first axis direction, the second portion having a main surface portion that is located in the first axis direction more than the top surface portion and extends radially outward from a second hole through which the shaft is inserted, an annular rib portion that protrudes from the main surface portion in the second axis direction and has an annular end face facing the plane, and a plurality of auxiliary rib portions that protrude from the main surface portion in the second axis direction and extend radially from the annular rib portion in the radial direction and have end faces facing the plane, A centrifugal fan comprising: a cylindrical second cylindrical portion extending in the second axial direction from the radially outer end of the main surface portion and having an inner cylindrical surface facing the outer cylindrical surface of the first cylindrical portion with a clearance between them; and adhesive portions formed by adhesive being provided between the annular end surface of the annular rib portion and the end surfaces of the plurality of auxiliary ribs and the plane.

2. The centrifugal fan according to claim 1, characterized in that the adhesive portion is provided across the inner circumferential surface of the annular rib portion, the outer circumferential surface of the annular rib portion, and each of the auxiliary rib portions on the side surfaces facing the circumferential direction of the shaft.

3. The centrifugal fan according to claim 1, characterized in that the main surface portion extends radially outward and toward the second axial direction from the second hole portion.

4. The centrifugal fan according to claim 3, characterized in that the plurality of auxiliary rib portions are radially extended outward from the annular rib portion.

5. The centrifugal fan according to claim 3 or 4, characterized in that the annular rib portion and the plurality of auxiliary rib portions are provided at positions spaced apart from the second cylindrical portion in the radial direction.

6. The centrifugal fan according to claim 5, characterized in that the annular rib portion and the plurality of auxiliary rib portions are provided at positions spaced apart from the second hole portion in the radial direction.

7. The centrifugal fan according to claim 1, characterized in that the first part is made of metal and the second part is made of resin.

8. A fixing method for fixing a second part, which is provided on a fan section having a plurality of blades and having a larger coefficient of linear expansion than the first part, to a first part provided on the rotor of a motor section having a rotor that rotates integrally with a shaft and a stator arranged opposite to the rotor, wherein the first part is provided with a top surface portion that extends radially outward from a first hole for shaft insertion and has a plane facing in the first axis direction, and a first cylindrical portion that extends radially outward from the radially outward end of the top surface portion in the second axis direction opposite to the first axis direction, wherein the second part is provided with a main surface portion that extends radially outward from a second hole for shaft insertion, an annular rib portion that protrudes from the main surface portion and has an annular end face, a plurality of auxiliary rib portions that protrude from the main surface portion in the same direction as the annular rib portion and extend radially from the annular rib portion and have end faces facing in the same direction as the annular end face, and a second cylindrical portion that extends radially outward from the radially outward end of the main surface portion in the same direction as the annular rib portion, and the fixing method is A fixing method comprising: a first step of applying adhesive to the annular end face, or applying adhesive to a location on the plane that faces the annular end face when the main surface of the second part is positioned on the first axial side of the top surface of the part of the plane; a second step of positioning the main surface of the second part on the first axial side of the top surface of the first part, so that the annular end face and the end face face each other on the plane; and a third step of positioning the inner surface of the second cylindrical part facing the outer surface of the first cylindrical part with a clearance between them, and spreading the adhesive between the annular end face and the plane, and between the end face and the plane.

Images