Balancing weight, blower, and method for manufacturing balancing weight

Abstract

The invention provides a balance weight, a blower, and a method for manufacturing the balance weight. A balance weight for adjusting the balance of a rotating body capable of rotating about a central axis, the rotating body having a first surface facing one side in a first direction and a second surface facing a second direction intersecting the first direction, the balance weight having a first contact portion in contact with the first surface and a second contact portion in contact with the second surface. When viewed from a direction perpendicular to the first direction, the surface of the balance weight facing the first direction has a curved portion protruding toward the first direction. The area of the projection of the balance weight on an imaginary plane perpendicular to the first direction is larger than the area of the first contact portion.

Description

Technical Field

[0001] The invention relates to a balancing weight, a blower and a method for manufacturing the balancing weight. Background Art

[0002] There is known a motor in which a balancing weight is applied to a rotor yoke to correct unbalanced rotation of the rotor yoke (for example, Patent Document 1).

[0003] Patent Document 1: Japanese Patent Application Publication No. 2001-298929

[0004] In the above motor, if the contact area between the balance weight and the rotor yoke is small, the bonding strength between the balance weight and the rotor yoke may not be sufficiently increased. Therefore, the balance weight may be separated from the rotor yoke due to the centrifugal force applied to the balance weight when the rotor yoke rotates. Summary of the invention

[0005] In view of the above circumstances, one object of one embodiment of the present invention is to provide a balancing weight, a blower, and a method for manufacturing the balancing weight, which are capable of improving the bonding strength between the balancing weight and a rotating body.

[0006] One embodiment of the present invention is a balancing weight that adjusts the balance of a rotating body that can rotate around a central axis, the rotating body having a first surface facing one side in a first direction and a second surface facing a second direction intersecting the first direction, wherein the balancing weight has a first contact portion that contacts the first surface and a second contact portion that contacts the second surface. When viewed from a direction perpendicular to the first direction, the surface of the balancing weight that faces the first direction has a curved portion that protrudes toward one side in the first direction. The area of ​​the balancing weight projected onto an imaginary surface perpendicular to the first direction is larger than the area of ​​the first contact portion.

[0007] One embodiment of the present invention is a blower having: the above-mentioned balancing weight; a rotor rotatable about a central axis; and an impeller connected to the rotor and rotatable about the central axis. The rotating body is composed of the rotor and the impeller.

[0008] One embodiment of the present invention is a method for manufacturing a balancing weight, wherein a balancing weight for adjusting the balance of the rotating body is molded on a rotating body, the rotating body having a first surface facing one side of a first direction and a second surface facing a second direction intersecting the first direction, and the balancing weight having a first contact portion in contact with the first surface and a second contact portion in contact with the second surface, wherein the method for manufacturing the balancing weight includes the following steps: a coating step of coating the molten balancing weight on the first surface; a blowing step of blowing air onto the balancing weight coated on the first surface to expand the balancing weight on the rotating body; and a curing step of curing the balancing weight. In the blowing process, air is blown toward the balancing weight so that the shape of the balancing weight becomes a shape in which, when viewed from a direction perpendicular to the first direction, the surface of the balancing weight facing the first direction has a curved portion protruding toward the first direction, and the area of ​​the projection of the balancing weight onto an imaginary plane perpendicular to the first direction is larger than the area of ​​the first contact portion, and the balancing weight is brought into contact with the second surface.

[0009] According to one aspect of the present invention, in a method for manufacturing a balance weight, a balance weight, and a blower, it is possible to improve the bonding strength between the balance weight and the rotating body. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 It is a top view which shows the air blower which concerns on 1st Embodiment.

[0011] Figure 2 The first embodiment shows the blower Figure 1 II-II sectional view.

[0012] Figure 3 It is a perspective view showing the impeller part according to the first embodiment.

[0013] Figure 4 It is a cross-sectional view showing the balance weight according to the first embodiment.

[0014] Figure 5 This is a diagram in which the balance weight of the first embodiment is projected onto a virtual plane.

[0015] Figure 6 This is a flowchart showing the method for manufacturing the balance weight according to the first embodiment.

[0016] Figure 7 It is a first cross-sectional view showing the method for manufacturing the balance weight according to the first embodiment.

[0017] Figure 8 It is a second cross-sectional view showing the method for manufacturing the balance weight according to the first embodiment.

[0018] Fig. 9 It is a cross-sectional view showing a balance weight according to a second embodiment.

[0019] Fig.10 It is a cross-sectional view showing a balance weight according to a third embodiment.

[0020] Description of symbols

[0021] 10, 210, 310: blower; 12: rotating body; 20: rotor; 60: impeller part; 61a: 1st outer side surface; 61c: groove part; 61d: 1st surface; 61e: 2nd surface; 61f: 3rd surface; 65, 265, 365: balance weight; 65e, 265e, 365e: 1st contact part; 65f: 2nd contact part; 366: 1st part; 367: 2nd part; A: air; D1: 1st direction; D2: 2nd direction; J: center axis; S03: coating process; S04: blowing process; S05: curing process; Sv: imaginary surface. DETAILED DESCRIPTION

[0022] Hereinafter, the blower of the embodiment of the present invention will be described with reference to the accompanying drawings. In addition, the scope of the present invention is not limited to the following embodiments, and can be arbitrarily changed within the scope of the technical concept of the present invention. In addition, in the following drawings, in order to facilitate the understanding of each structure, the scale, number, etc. in each structure are sometimes different from the actual structure.

[0023] The Z-axis direction appropriately shown in each figure is the direction in which the central axis J of the rotating body extends. The central axis J is an imaginary axis. In the following description, the direction parallel to the Z-axis direction is referred to as the "axial direction". The radial direction centered on the central axis J is referred to as the "radial direction". The circumferential direction centered on the central axis J is referred to as the "circumferential direction". In each figure, the circumferential direction is represented by the arrow θ. The side (+Z side) to which the arrow of the Z-axis in the axial direction points is referred to as the "upper side". The opposite side (-Z side) to the side to which the arrow of the Z-axis in the axial direction points is referred to as the "lower side". In addition, the upper side and the lower side are merely names used to illustrate the relative positional relationship of each part, and the actual configuration relationship, etc. may also be a configuration relationship other than the configuration relationship represented by these names, etc.

[0024] The circumferential direction is indicated by an arrow θ in each figure. The side to which the arrow θ in the circumferential direction points is referred to as "one circumferential side". The side opposite to the side to which the arrow θ in the circumferential direction points is referred to as "the other circumferential side". The one circumferential side (+θ side) is the side that moves counterclockwise around the center axis J when viewed from the top. The other circumferential side (-θ side) is the side that moves clockwise around the center axis J when viewed from the top.

[0025] The first direction D1 appropriately shown in each figure is the direction in which the first surface of the rotating body faces. In the present embodiment, the first surface is a surface on which a balancing weight is molded. In the present embodiment, the first direction D1 is a direction parallel to the axial direction. The first direction D1 may also be a direction intersecting the axial direction. In the following description, the side (+D1 side) to which the arrow of the first direction D1 faces is referred to as "one side of the first direction D1", and the opposite side (-D1 side) to which the arrow of the first direction D1 faces is referred to as "the other side of the first direction D1". One side (+D1 side) of the first direction D1 faces the same direction as the upper side. The other side (-D1 side) of the first direction D1 faces the same direction as the lower side. The second direction D2 appropriately shown in each figure is a direction intersecting the first direction D1. In the present embodiment, the second direction D2 is a direction perpendicular to the first direction D1. In the present embodiment, the second direction D2 is a direction parallel to the radial direction.

[0026] <First embodiment>

[0027] Figure 1 The blower 10 of the present embodiment shown in FIG. 1 is, for example, an electric cooling fan for air cooling electronic equipment. The blower 10 of the present embodiment is an axial flow fan that blows air in the axial direction. Figure 2 As shown, the blower 10 includes a motor 15, a housing 50, an impeller 60, and a balance weight 65. In addition, the blower 10 includes a rotating body 12.

[0028] The impeller portion 60 is rotatable about the central axis J. The impeller portion 60 includes an impeller cup 61 and a plurality of wing portions 62. The impeller cup 61 is substantially cylindrical and extends axially about the central axis J. The impeller cup 61 is open at the bottom. The motor 15 is accommodated inside the impeller cup 61. Figure 3 As shown, the impeller cup 61 has a first outer side surface 61a, a groove portion 61c, a first surface 61d, a second surface 61e, and a third surface 61f.

[0029] The first outer side surface 61a is a surface facing one side (+D1 side) of the outer side surface of the impeller portion 60 in the first direction D1. When viewed from the axial direction, the first outer side surface 61a is substantially circular with the central axis J as the center. The groove portion 61c is a groove that is recessed from the first outer side surface 61a to the lower side, that is, the other side (-D1 side) in the first direction D1. When viewed from the axial direction, the groove portion 61c is annular with the central axis J as the center. The groove portion 61c extends over the entire circumference along the circumferential direction.

[0030] In the present embodiment, the first surface 61d is a surface of the inner side surface of the groove portion 61c that faces the upper side, that is, the side (+D1 side) of the first direction D1. When viewed from the axial direction, the first surface 61d is annular. The first surface 61d extends over the entire circumference along the circumferential direction. In the present embodiment, the second surface 61e is a surface of the inner side surface of the groove portion 61c that faces the radial inner side. The second surface 61e faces the second direction D2. The second surface 61e faces the direction intersecting the first direction D1. In the present embodiment, the second surface 61e faces the direction perpendicular to the first direction D1. When viewed from the axial direction, the second surface 61e is circumferential. The second surface 61e extends over the entire circumference along the circumferential direction. In the present embodiment, the third surface 61f is a surface of the inner side surface of the groove portion 61c that faces the radial outer side. The third surface 61f faces the second direction D2. The third surface 61f faces the direction intersecting the first direction D1. In the present embodiment, the third surface 61f faces a direction perpendicular to the first direction D1. The third surface 61f and the second surface 61e face each other in the radial direction.

[0031] The plurality of wings 62 protrude radially outward from the outer circumference of the impeller cup 61. The impeller portion 60 has five wings 62. The wings 62 are arranged in a circumferential direction along the outer circumference of the impeller cup 61. When the impeller portion 60 rotates around the central axis J, the wings 62 send air in the axial direction.

[0032] like Figure 2 As shown in FIG. 1 , the housing 50 accommodates the motor 15 and the impeller 60 therein. The housing 50 holds the motor 15 and the impeller 60. The housing 50 has a peripheral wall portion 51 and a motor holding portion 55. Figure 1 and Figure 2 As shown in FIG. 5 , the peripheral wall portion 51 is in the shape of a square tube extending in the axial direction. Figure 2 As shown, the peripheral wall portion 51 surrounds the impeller portion 60 and the motor 15 from the radially outer side. The motor holding portion 55 has a cylindrical shape extending in the axial direction around the central axis J. The motor holding portion 55 is arranged inside the impeller cup 61 .

[0033] The motor 15 is housed inside the peripheral wall portion 51. The motor 15 includes a rotor 20, a shaft 23, a first bearing 24a, a second bearing 24b, a rotor bearing 25, a stator 30, and a circuit board 70. The motor 15 of the present embodiment is an outer rotor type motor in which the rotor 20 is arranged radially outside the stator 30. The rotor 20 can rotate around the central axis J. The rotor 20 is held on the inner circumferential surface of the impeller cup 61. Thus, the impeller portion 60 is connected to the rotor 20. When the rotor 20 rotates around the central axis J, the impeller portion 60 rotates around the central axis J. The rotor 20 includes a magnet 22.

[0034] The shaft 23 is cylindrical and extends axially with the central axis J as the center. The shaft 23 is arranged inside the motor holding portion 55. The upper part of the shaft 23 is held rotatably by the first bearing 24a. The lower part of the shaft 23 is held rotatably by the second bearing 24b. The first bearing 24a and the second bearing 24b are respectively held on the inner circumferential surface of the motor holding portion 55. Thus, the shaft 23 can rotate around the central axis J. The rotor bearing 25 is roughly cylindrical with the central axis J as the center. The shaft 23 is inserted into the rotor bearing 25 in the axial direction. A portion including the upper end of the shaft 23 is embedded in the rotor bearing 25. The rotor bearing 25 supports the rotor 20 so that it can rotate around the central axis J.

[0035] The stator 30 has an annular shape surrounding the central axis J. The stator 30 is disposed inside the rotor 20. The stator 30 faces the magnet 22 in the radial direction with a gap therebetween. The stator 30 includes a stator core 31, a coil portion 35, an insulator 40, and a connection pin 80.

[0036] The stator core 31 is in the shape of a ring surrounding the central axis J. The stator core 31 has a core back 32 and a plurality of teeth 33. The core back 32 is in the shape of a ring centered on the central axis J. The core back 32 is fixed to the outer peripheral surface of the motor retaining portion 55. Each tooth 33 protrudes radially outward from the outer peripheral surface of the core back 32. Although not shown in the figure, each tooth 33 is arranged at intervals along the outer peripheral surface of the core back 32. The insulator 40 insulates the stator core 31 from the coil portion 35. The insulator 40 is mounted on the stator core 31.

[0037] The connection pin 80 is in the shape of a column extending in the axial direction. The connection pin 80 is conductive. Although not shown in the figure, the stator 30 has two connection pins 80. Each connection pin 80 is held by the insulating member 40. Although not shown in the figure, the lower end of each connection pin 80 is connected to the circuit board 70.

[0038] The coil portion 35 is electrically connected to the circuit board 70 via the connection pin 80. When current is supplied from the circuit board 70 to the coil portion 35, a rotation torque is generated in the rotor 20 by the magnetic force between the magnetic poles of the electromagnet formed by the stator 30 and the magnet 22. The coil portion 35 has a plurality of coil main bodies 36 and coil lead wires 38.

[0039] Each coil body 36 is mounted on a different tooth portion 33 of the stator core 31 via an insulating member 40. A coil lead wire 38 is led out from the coil body 36. Although not shown in the figure, in the present embodiment, the stator 30 has two coil lead wires 38. Each coil lead wire 38 is connected to a different connecting pin 80. Thus, the coil portion 35 is electrically connected to the circuit board 70 via the connecting pin 80.

[0040] The circuit board 70 is arranged below the stator core 31. The circuit board 70 is in the shape of a plate extending in a direction perpendicular to the axial direction. As described above, the circuit board 70 is connected to the connection pin 80. The circuit board 70 supplies current to the coil portion 35 via the connection pin 80.

[0041] In the present embodiment, the rotating body 12 is a component that can rotate around the central axis J among the components of the blower 10. In the present embodiment, the rotating body 12 is composed of an impeller portion 60 and a rotor 20. In the present embodiment, a balancing weight 65 is molded on the rotating body 12. In the present embodiment, the balancing weight 65 is molded on the impeller portion 60. The balancing weight 65 can be molded on the rotor 20, or can be molded on the impeller portion 60 and the rotor 20 separately.

[0042] like Figure 3 As shown, the balancing weight 65 is arranged inside the groove 61c of the impeller part 60. The balancing weight 65 is molded on the first surface 61d. In the present embodiment, the balancing weight 65 is a weight for adjusting the balance of the rotating body 12. The balancing weight 65 of the present embodiment is composed of one part, so the number of parts Na of the balancing weight 65 is 1. By molding the balancing weight 65 of a predetermined weight at a predetermined position in the circumferential direction of the first surface 61d, the deviation of the center of gravity position of the rotating body 12 relative to the central axis J can be reduced. Thus, the rotating body 12 can stably rotate around the central axis J. In addition, the impeller part 60 may not have the groove 61c, in which case the balancing weight 65 may be molded on the first outer side surface 61a. In addition, the balancing weight 65 may be molded on the outer surface of the rotor 20. For example, when the balancing weight 65 is molded on the surface of the rotor 20 facing the radial direction, the first direction D1 is a direction perpendicular to the axial direction, and the second direction D2 is a direction intersecting the radial direction.

[0043] like Figure 4 As shown in the figure, in this embodiment, the balance weight 65 includes a metal powder 65b and a resin part 65a containing the powder 65b. As a material constituting the powder 65b, metals such as tungsten and stainless steel can be used. The resin part 65a is composed of a thermoplastic resin. As a material constituting the resin part 65a, a thermoplastic resin such as polyethylene, polypropylene, and polyvinyl chloride can be used.

[0044] like Figure 3 As shown in FIG. 1 , the balance weight 65 of this embodiment is substantially spherical and flat in the axial direction. Figure 4As shown, when viewed from a direction perpendicular to the first direction D1, the balancing weight 65 is in a generally elliptical shape with the minor axis extending in the axial direction. The upper end of the balancing weight 65 is located at a position lower than the first outer side surface 61a. The upper end of the balancing weight 65 may also be located at a position higher than the first outer side surface 61a. When viewed from a direction perpendicular to the first direction D1, the dimension of the balancing weight 65 in the second direction D2 increases from the lower end toward the upper side, and after the dimension of the second direction D2 becomes the largest, the dimension of the second direction D2 decreases toward the upper side. That is, the dimension of the balancing weight 65 in the direction perpendicular to the first direction D1 is the largest between the upper end and the lower end. In the following description, the maximum dimension of the balancing weight 65 in the second direction D2 is referred to as the dimension L2 of the balancing weight 65. The dimension L3 of the balancing weight 65 in the first direction D1 is smaller than the dimension L2 in the second direction D2 which is the direction perpendicular to the first direction D1.

[0045] When viewed from a direction perpendicular to the first direction D1, the upper surface 65h of the balancing weight 65, which faces upward, that is, the surface on one side (+D1 side) in the first direction D1, is in a curved shape convex to the upper side. That is, when viewed from a direction perpendicular to the first direction D1, the upper surface 65h has a curved portion convex to the upper side. In the present embodiment, when viewed from a direction perpendicular to the first direction D1, the upper surface 65h is in a substantially elliptical arc shape convex to the upper side. The balancing weight 65 has a first contact portion 65e and a second contact portion 65f.

[0046] The first contact portion 65e is a surface of the outer side surface of the balance weight 65 that contacts the first surface 61d of the rotating body 12. The first contact portion 65e is bonded to the first surface 61d. Thus, the balance weight 65 is fixed to the rotating body 12. The first contact portion 65e extends in a direction perpendicular to the first direction D1. In the second direction D2, which is a direction perpendicular to the first direction D1, the dimension L1 of the first contact portion 65e is smaller than the dimension L2 of the balance weight 65. Figure 5 The virtual surface Sv shown is a virtual surface extending in a direction perpendicular to the first direction D1. The outer edge of the balance weight 65 projected on the virtual surface Sv surrounds the outer edge of the first contact portion 65e. The area Sb of the balance weight 65 projected on the virtual surface Sv is larger than the area S1 of the first contact portion 65e.

[0047] like Figure 4As shown, the second contact portion 65f is a surface of the outer side surface of the balancing weight 65 that contacts the second surface 61e of the rotating body 12. The second contact portion 65f is bonded to the second surface 61e. Thus, the balancing weight 65 is fixed to the rotating body 12. The second contact portion 65f extends in the axial direction and the circumferential direction. Although omitted from the illustration, the outer edge of the balancing weight 65 projected on the second surface 61e surrounds the outer edge of the second contact portion 65f. In the present embodiment, the balancing weight 65 is arranged with a gap in the radial direction from the third surface 61f.

[0048] Next, a manufacturing method Mb of the balancing weight 65 of the present embodiment will be described. In the manufacturing method Mb of the balancing weight 65, the balancing weight 65 is molded on the rotating body 12. Figure 6 As shown, the manufacturing method Mb of the balancing weight 65 of the present embodiment includes the following steps: a first inspection step S02, which inspects the balance of the rotating body 12; a coating step S03, which coats the melted balancing weight 65 on the first surface 61d of the rotating body 12; a blowing step S04, which blows air A to the balancing weight 65 coated on the first surface 61d to spread the balancing weight 65 on the rotating body 12; a solidification step S05, which solidifies the balancing weight 65; and a second inspection step S08, which inspects the balance of the rotating body 12 formed with the balancing weight 65. In addition, in the following description, "operators, etc." include operators and assembly devices, etc., who perform various operations. Each operation may be performed only by an operator, only by an assembly device, or by an operator and an assembly device.

[0049] When the molding of the balancing weight 65 starts, the number of parts of the balancing weight 65 formed on the rotating body 12, that is, Nm, is 0 (S01). In addition, as described above, the number of parts Na of the balancing weight 65 in this embodiment is 1. In the first inspection step S02, the balance of the rotating body 12 is inspected. Although the illustration is omitted, the operator or the like measures the offset of the center of gravity position of the rotating body 12 relative to the central axis J, that is, the center of gravity offset, by a known balance measuring device. The balance measuring device can also measure the center of gravity offset by rotating the rotating body 12, or can measure the center of gravity offset while the rotating body 12 is stationary. The operator or the like calculates the position of the molded balancing weight 65, that is, the molding position Pm, and the weight of the molded balancing weight 65, that is, the molding weight Wb, based on the center of gravity offset. When the molding position Pm and the molding weight Wb are calculated, the first inspection step S02 ends. In addition, the molding position Pm and the molding weight Wb can also be calculated by the balance measuring device. In addition, in this embodiment, the molding position Pm is a part of the first surface 61d. The molding position Pm may be a portion other than the first surface 61 d of the impeller portion 60 , or may be a portion of the rotor 20 .

[0050] In the coating step S03, the melted balance weight 65 is coated on the rotating body 12. Figure 7 As shown, in the coating process S03, the operator or the like uses the coating device 91 disposed at a position above the impeller part 60 to coat the heated and melted balancing weight 65 on the first surface 61d. In the present embodiment, the balancing weight 65 contains powder 65b, so the melted balancing weight 65 is in a paste state. In the present embodiment, the coating device 91 is a dispenser capable of ejecting a predetermined weight of the melted balancing weight 65. Therefore, the difference between the weight of the melted balancing weight 65 coated on the rotating body 12 and the molding weight Wb can be reduced. In addition, the coating device 91 is connected to the inside of a container having a heating unit such as a heater not shown. The balancing weight 65 heated and melted by the heating unit is stored inside the container. The melted balancing weight 65 inside the container is provided to the coating device 91. When the melted balancing weight 65 of the molding weight Wb is coated on the molding position Pm of the first surface 61d by the coating device 91, the coating process S03 ends.

[0051] The molten balance weight 65 has a certain degree of viscosity, so Figure 8 As shown in FIG. 1 , the shape of the balancing weight 65 applied to the first surface 61d is substantially spherical. In addition, a protrusion 65c protruding toward one side (+D1 side) in the first direction D1 is formed on the surface of the balancing weight 65. Although not shown in the figure, in this embodiment, the size of the balancing weight 65 applied to the first surface 61d in the second direction D2 is smaller than that of the balancing weight 65 in the first direction D1. Figure 4 The dimension L2 of the second direction D2 of the balance weight 65 shown molded on the first surface 61 d is small.

[0052] In the blowing process S04, air A is blown toward the balancing weight 65 applied to the rotating body 12, so that the balancing weight 65 is expanded on the rotating body 12. In the blowing process S04, the operator or the like uses the blowing device 92 arranged at a position above the impeller part 60 to blow air A from the upper side toward the melted balancing weight 65. The air A is compressed air compressed by a compressor not shown. In addition, in the present embodiment, the temperature of the air A is a temperature higher than the melting point of the resin part 65a of the balancing weight 65. The temperature of the air A may also be a temperature lower than the melting point of the resin part 65a of the balancing weight 65.

[0053] The melted balance weight 65 is spread along the first surface 61d by the wind pressure of the air A. In addition, the protrusion 65c enters the inside of the melted balance weight 65 by the wind pressure of the air A. Figure 4As shown, when viewed from a direction perpendicular to the first direction D1, the balancing weight 65 is in a generally elliptical shape with a minor axis extending in the axial direction. In more detail, the dimension L3 of the balancing weight 65 in the first direction D1 is smaller than the dimension L2 of the balancing weight 65 in the direction perpendicular to the first direction D1. In addition, when viewed from a direction perpendicular to the first direction D1, the upper surface 65h has a curved portion protruding upward. When viewed from a direction perpendicular to the first direction D1, the upper surface 65h is in a generally elliptical arc shape protruding upward. In addition, the first contact portion 65e contacts the first surface 61d. The second contact portion 65f contacts the second surface 61e. When the balancing weight 65 is expanded on the rotating body 12, the blowing process S04 ends.

[0054] In the solidification step S05, the balancing weight 65 is solidified. In the solidification step S05, the operator solidifies the balancing weight 65 by cooling the melted balancing weight 65. The cooling of the balancing weight 65 may be performed in a room temperature atmosphere, or may be performed in a low temperature atmosphere by storing the rotating body 12 in a cooling furnace (not shown) or the like. When the balancing weight 65 is solidified, the solidification step S05 ends. In addition, in the present embodiment, the operator ends the solidification step S05 before the balancing weight 65 is completely solidified. In more detail, the operator solidifies the balancing weight 65 to the point where it can be maintained even if vibration is applied to the rotating body 12. Figure 4 When the balancing weight 65 has a hardness of the shape shown, the curing step S05 is terminated. Alternatively, the operator or the like may terminate the curing step S05 after the balancing weight 65 is completely cured.

[0055] like Figure 6 As shown, when the curing step S05 is completed, the number of parts of the balancing weight 65 formed on the rotating body 12, that is, Nm, is 1 (S06). In addition, as described above, in this embodiment, the number of parts Na of the balancing weight 65 formed is 1, so the balancing weight 65 of the predetermined number of parts is formed on the rotating body 12. Therefore, the operator performs the second inspection step S08 (S07).

[0056] In the second inspection step S08, the balance of the rotating body 12 with the balancing weight 65 is inspected. The operator measures the center of gravity offset of the rotating body 12 with the balancing weight 65 molded therein by means of the above-mentioned balance measuring device (not shown) or the like. When the center of gravity offset of the rotating body 12 is less than a prescribed amount, that is, when the balance of the rotating body 12 is within prescribed specifications (S09), the operator ends the molding of the balancing weight 65. At this time, the balance of the rotating body 12 is adjusted by the balancing weight 65. In addition, when the balance of the rotating body 12 is outside prescribed specifications (S09), the operator performs the second inspection step S08 after molding the balancing weight 65 of the molding weight Wb at the newly calculated molding position Pm (S03 to S06). The operator repeats the second inspection step S08 and the molding of the balancing weight 65 until the balance of the rotating body 12 is within the specified specification. When the balance of the rotating body 12 is within the specified specification, the operator ends the molding of the balancing weight 65 (S09). At this time, the balance of the rotating body 12 is adjusted by the balancing weight 65.

[0057] According to the present embodiment, the balancing weight 65 has a first contact portion 65e in contact with the first surface 61d and a second contact portion 65f in contact with the second surface 61e. Therefore, in addition to contacting the first surface 61d of the rotating body 12, the balancing weight 65 also contacts the second surface 61e, so that the contact area between the balancing weight 65 and the rotating body 12 can be increased. Therefore, the bonding strength between the balancing weight 65 and the rotating body 12 can be improved. Thus, when the blower 10 is in operation, it is possible to suppress the balancing weight 65 from being peeled off from the rotating body 12 due to the centrifugal force applied to the balancing weight 65 when the rotating body 12 rotates around the central axis J. Therefore, the rotational balance of the rotating body 12 can be appropriately stabilized, so that the rotating body 12 can be stably rotated around the central axis J. Thus, the vibration and noise when the blower 10 is in operation can be suppressed.

[0058] In the case where the balancing weight 65 is in contact with only the first surface 61d of the rotating body 12, in order to increase the contact area between the balancing weight 65 and the rotating body 12, in the blowing process S04, it is necessary to expand the melted balancing weight 65 to a larger range in the direction perpendicular to the first direction D1. Therefore, in the blowing process S04, it is necessary to extend the time for blowing the air A to the melted balancing weight 65, or increase the speed and pressure of the air A blown to the balancing weight 65. Therefore, the operation man-hours of the blowing process S04 increase, and the manufacturing cost of the blowing device 92 may increase. In contrast, in the present embodiment, as described above, the balancing weight 65 is in contact with the second surface 61e in addition to the first surface 61d, so that the contact area between the balancing weight 65 and the rotating body 12 can be increased without increasing the range of expanding the melted balancing weight 65 in the direction perpendicular to the first direction D1. Thus, in the blowing step S04, it is possible to suppress the increase in the time for blowing the air A to the molten balance weight 65 or the speed and pressure of the air A blown to the balance weight 65. Therefore, it is possible to suppress the increase in the working hours of the blowing step S04 and the manufacturing cost of the blowing device 92, and improve the bonding strength between the balance weight 65 and the rotating body 12.

[0059] In addition, according to the present embodiment, when viewed from a direction perpendicular to the first direction D1, the upper surface 65h facing the upper side, that is, the side (+D1 side) of the first direction, has a curved portion protruding toward the upper side. The area Sb projected onto the imaginary surface Sv perpendicular to the first direction D1 is larger than the area S1 of the first contact portion 65e. When the balancing weight 65 is in such a shape, the balancing weight 65 can be molded without significantly changing the shape of the balancing weight 65 just after being coated by the coating device 91. Therefore, the time for blowing air A to the molten balancing weight 65 or the speed and pressure of the air A blown to the balancing weight 65 can be reduced. Therefore, in the present embodiment, the balancing weight 65 can be made into the above-mentioned shape by blowing air A to the molten balancing weight 65, and the balancing weight 65 is made to contact with two surfaces. Therefore, it is possible to suppress the time of blowing the air A to the melted balance weight 65 or the increase in the speed and pressure of the air A blown to the balance weight 65 and improve the bonding strength between the balance weight 65 and the rotating body 12 .

[0060] In addition, in the present embodiment, in the blowing step S04, the air A is blown to the protrusion 65c formed on the surface of the balance weight 65 in the coating step S03, so that the protrusion 65c can enter the balance weight 65 as described above. Therefore, when the air blower 10 is operating, the protrusion 65c can be prevented from falling off from the balance weight 65. Therefore, it is possible to prevent the protrusion 65c from biting into, for example, between the rotor 20 and the stator 30, so that the stability of the operation of the air blower 10 can be improved.

[0061] In addition, in this embodiment, compared with the case where the balance weight 65 has the protrusion 65 c protruding upward, the air resistance applied to the balance weight 65 when the rotating body 12 rotates around the central axis J can be reduced. Therefore, the rotating body 12 can be rotated around the central axis J more stably, and the driving efficiency of the blower 10 can be improved.

[0062] According to the present embodiment, the dimension L3 of the balancing weight 65 in the first direction D1 is smaller than the dimension L2 in the direction perpendicular to the first direction D1. Therefore, it is easy to reduce the dimension L3 of the balancing weight 65 in the first direction D1, that is, the height of the balancing weight 65, and thus it is easy to reduce the air resistance applied to the balancing weight 65 when the rotating body 12 rotates around the central axis J. Therefore, the rotating body 12 can be rotated around the central axis J more stably, and the driving efficiency of the blower 10 can be improved more appropriately.

[0063] According to the present embodiment, the rotating body 12 has a first outer side surface 61a facing upward, i.e., one side (+D1) of the first direction D1, and a groove portion 61c recessed from the first outer side surface 61a to the lower side, i.e., the other side (-D1 side) of the first direction D1, the first surface 61d is the surface facing upward among the inner side surfaces of the groove portion 61c, and the second surface 61e is the surface facing in a direction perpendicular to the first direction D1 among the inner side surfaces of the groove portion 61c. The balancing weight 65 is arranged inside the groove portion 61c. Thus, the balancing weight 65 is arranged inside the groove portion 61c, so that the air resistance applied to the balancing weight 65 when the rotating body 12 rotates around the central axis J can be more appropriately reduced. Therefore, the rotating body 12 can be rotated around the central axis J more stably, and the driving efficiency of the blower 10 can be more appropriately improved.

[0064] According to the present embodiment, the groove portion 61c extends along the circumferential direction over the entire circumference, and the second surface 61e is a surface facing radially inward. Therefore, when the rotating body 12 rotates around the central axis J, if a centrifugal force toward the radially outward side is applied to the balancing weight 65, the balancing weight 65 is pressed against the second surface 61e contacted by the second contact portion 65f. Thus, it is possible to suppress the balancing weight 65 from moving radially outward. Therefore, when the blower 10 is in operation, it is possible to more appropriately suppress the balancing weight 65 from peeling off from the rotating body 12. Thus, the rotational balance of the rotating body 12 can be more appropriately stabilized, so that the rotating body 12 can be rotated more stably around the central axis J.

[0065] When the balancing weight 65 is applied to the inside of the groove portion 61c by a scraper or other component, a rib is sometimes provided inside the groove portion 61c in order to scrape the balancing weight 65 from the scraper or other component. In contrast, in the present embodiment, as described above, the balancing weight 65 is applied to the first surface 61d by the coating device 91 in the coating step S03. Therefore, even in a structure in which the groove portion 61c extends over the entire circumference, that is, a structure in which no rib is provided on the groove portion 61c, the balancing weight 65 can be easily applied to the inside of the groove portion 61c. Therefore, in the present embodiment, the shape of the groove portion 61c can be simplified, and thus the structure of the mold used when molding the impeller portion 60 can be simplified. Therefore, the increase in the manufacturing cost of the mold can be suppressed.

[0066] According to the present embodiment, the blower 10 has a balancing weight 65, a rotor 20 that can rotate around a central axis J, and an impeller portion 60 that is connected to the rotor 20 and can rotate around the central axis J. The rotating body 12 is composed of the rotor 20 and the impeller portion 60. As described above, by means of the balancing weight 65 formed on the rotating body 12, the balance of the rotating body 12 can be adjusted, so that the rotor 20 can be stably rotated around the central axis J. Thus, when the rotor 20 rotates around the central axis J, the radial position of the rotor 20 relative to the stator 30 can be suppressed from changing. Therefore, the magnetic force between the magnetic poles of the electromagnet formed by the stator 30 and the magnets 22 of the rotor 20 can be suppressed from changing, so that the rotation speed and rotation torque of the rotor 20 and the impeller portion 60 can be stabilized. Thus, the operation of the blower 10 can be stabilized.

[0067] According to the present embodiment, the manufacturing method Mb of the balancing weight 65 is a manufacturing method of the balancing weight in which the balancing weight 65 having the first contact portion 65e in contact with the first surface 61d and the second contact portion 65f in contact with the second surface 61e is molded on the rotating body 12, and includes the following steps: a coating step S03 of coating the molten balancing weight 65 on the first surface 61d; a blowing step S04 of blowing air A to the balancing weight 65 coated on the first surface 61d to spread the balancing weight 65 on the rotating body 12; and a solidification step S05 of solidifying the balancing weight 65. Therefore, in the blowing step S04, the balancing weight 65 can be spread on the rotating body 12, so that the contact area between the first contact portion 65e and the first surface 61d can be increased. In addition, by extending the balancing weight 65 on the rotating body 12, the balancing weight 65 can be brought into contact with the second surface 61e, so that the second contact portion 65f in contact with the second surface 61e can be stably formed. Thus, the contact area between the balancing weight 65 and the rotating body 12 can be increased, so that the bonding strength between the balancing weight 65 and the rotating body 12 can be improved.

[0068] In addition, in the present embodiment, the balancing weight 65 includes a metal powder 65b and a resin portion 65a containing the powder 65b. Therefore, the specific gravity of the balancing weight 65 can be increased compared to the case where the balancing weight 65 does not include the metal powder 65b. As a result, the volume of the balancing weight 65 molded on the rotating body 12 can be reduced, so that the operation time of applying the molten balancing weight 65 to the rotating body 12 in the coating step S03 and the time of solidifying the balancing weight 65 in the solidification step S05 can be suppressed from increasing. Therefore, the increase in the manufacturing man-hours of the balancing weight 65 can be suppressed, and thus the increase in the manufacturing man-hours of the blower 10 can be suppressed.

[0069] In addition, in the present embodiment, the balancing weight 65 is spread on the rotating body 12 in the blowing step S04, so that the surface area of ​​the balancing weight 65 can be increased. As a result, in the curing step S05, the cooling efficiency of the balancing weight 65 can be improved, so that the curing time of the balancing weight 65 can be shortened. Therefore, the increase in the manufacturing man-hours of the balancing weight 65 can be suppressed, and the increase in the manufacturing man-hours of the blower 10 can be suppressed.

[0070] <Second embodiment>

[0071] like Fig. 9 As shown, the balancing weight 265 of the blower 210 of this embodiment contacts the first surface 61d, the second surface 61e, and the third surface 61f of the rotating body 12. In the following description, the same reference numerals are given to the same components as those of the first embodiment, and the description thereof is omitted.

[0072] When viewed from a direction perpendicular to the first direction D1, the balancing weight 265 is in a generally elliptical shape with a minor axis extending in the axial direction. The balancing weight 265 has the largest dimension in the direction perpendicular to the first direction D1 between the upper end and the lower end. The dimension L23 of the balancing weight 265 in the first direction D1 is smaller than the dimension L22 in the direction perpendicular to the first direction D1, i.e., the second direction D2. When viewed from a direction perpendicular to the first direction D1, the upper surface 265h of the balancing weight 265 is in a curved shape convex to the upper side. That is, when viewed from a direction perpendicular to the first direction D1, the upper surface 265h has a curved portion convex to the upper side. The balancing weight 265 has a first contact portion 265e, a second contact portion 265f, and a third contact portion 265g.

[0073] The first contact portion 265e is a surface of the outer side surface of the balancing weight 265 that contacts the first surface 61d of the rotating body 12. The first contact portion 265e is bonded to the first surface 61d. In the second direction D2, which is a direction perpendicular to the first direction D1, the dimension L21 of the first contact portion 265e is smaller than the dimension L22 of the balancing weight 265. Although not shown in the figure, the area Sb of the balancing weight 265 projected on the imaginary surface Sv is larger than the area S1 of the first contact portion 265e. The other structures of the first contact portion 265e of this embodiment are the same as the other structures of the first contact portion 65e of the first embodiment described above.

[0074] The third contact portion 265g is a surface of the outer side surface of the balancing weight 265 that contacts the third surface 61f of the rotating body 12. In the present embodiment, the balancing weight 265 contacts the third surface 61f. As described above, the third surface 61f faces radially outward. The third contact portion 265g is bonded to the third surface 61f. Thus, the balancing weight 265 is fixed to the rotating body 12. The third contact portion 265g extends in the axial direction and the circumferential direction. Other structures of the air blower 210 of the present embodiment are the same as other structures of the air blower 10 of the first embodiment described above.

[0075] According to the present embodiment, the balancing weight 265 contacts the third surface 61f of the inner side surface of the groove portion 61c that faces radially outward. Therefore, in addition to contacting the first surface 61d and the second surface 61e of the rotating body 12, the balancing weight 265 also contacts the third surface 61f, so that the contact area between the balancing weight 265 and the rotating body 12 can be further increased. Therefore, the bonding strength between the balancing weight 265 and the rotating body 12 can be further improved. As a result, when the blower 210 is in operation, the balancing weight 265 can be more appropriately prevented from peeling off from the rotating body 12. Therefore, the rotational balance of the rotating body 12 can be more appropriately stabilized, so that the rotating body 12 can be rotated more stably around the central axis J.

[0076] <Third embodiment>

[0077] like Fig.10 As shown, the balancing weight 365 included in the blower 310 of the present embodiment is composed of a plurality of parts molded on the rotating body 12. In the following description, the same reference numerals are given to the same components as those of the first embodiment, and the description thereof will be omitted.

[0078] The balancing weight 365 is axially flat. The balancing weight 365 has the largest dimension in the direction perpendicular to the first direction D1 between the upper end and the lower end. The dimension L33 of the balancing weight 365 in the first direction D1 is smaller than the dimension L32 in the circumferential direction perpendicular to the first direction D1. The balancing weight 365 of the present embodiment has a first part 366 and a second part 367. The balancing weight 365 of the present embodiment is composed of two parts, the first part 366 and the second part 367. The number of parts Na of the balancing weight 365 of the present embodiment is 2. The balancing weight 365 may also be composed of more than three parts. In addition, the balancing weight 365 has a first contact portion 365e and a second contact portion not shown in the figure. The second contact portion contacts the second surface not shown in the figure.

[0079] When viewed from a direction perpendicular to the first direction D1, the first portion 366 is in a generally elliptical shape with a minor axis extending in the axial direction. The first portion 366 has a maximum dimension in a direction perpendicular to the first direction D1 between the upper end and the lower end. When viewed from a direction perpendicular to the first direction D1, the surface of the first portion 366 facing upward, that is, the first upper surface 366h on one side (+D1 side) of the first direction D1, is in a curved shape convex to the upper side. That is, when viewed from a direction perpendicular to the first direction D1, the first upper surface 366h has a curved portion convex to the upper side. The first portion 366 is in contact with the first surface 61d. Although not shown in the figure, the first portion 366 is in contact with the second surface. That is, the first portion 366 is in contact with both the first surface 61d and the second surface. The first portion 366 may also be in contact with the third surface 61f.

[0080] The second portion 367 is axially flat. In the present embodiment, the second portion 367 is disposed on the other circumferential side (-θ side) of the first portion 366. The second portion 367 may also be disposed on one circumferential side (+θ side) of the first portion 366 and on the radially inner side of the first portion 366. The second portion 367 is connected to the first portion 366 in the circumferential direction. The second portion 367 may not be connected to the first portion 366.

[0081] When viewed from a direction perpendicular to the first direction D1, the second portion 367, which faces upward, i.e., the surface on one side (+D1 side) of the first direction D1, i.e., the second upper surface 367h, is in a curved shape convex to the upper side. That is, when viewed from a direction perpendicular to the first direction D1, the second upper surface 367h has a curved portion convex to the upper side. In the present embodiment, the surface facing upward, i.e., the upper surface 365h of the balance weight 365 is composed of the first upper surface 366h and the second upper surface 367h. Therefore, when viewed from a direction perpendicular to the first direction D1, the upper surface 365h has a curved portion convex to the upper side. The second portion 367 is in contact with the first surface 61d. The second portion 367 may or may not be in contact with the second surface 61e and the third surface 61f. The second portion 367 is in contact with at least the first surface 61d.

[0082] The first contact portion 365e is a surface of the outer side surface of the balancing weight 365 that contacts the first surface 61d of the rotating body 12. The first contact portion 365e is bonded to the first surface 61d. In the present embodiment, the first contact portion 365e is composed of a portion of the outer side surface of each of the first portion 366 and the second portion 367 that contacts the first surface 61d. In the circumferential direction, which is a direction perpendicular to the first direction D1, the dimension L31 of the first contact portion 365e is smaller than the dimension L32 of the balancing weight 365. Although not shown in the figure, the area Sb of the balancing weight 365 projected on the imaginary surface Sv is larger than the area S1 of the first contact portion 365e.

[0083] Next, the manufacturing method Mb of the balancing weight 365 of this embodiment is described. In this embodiment, the coating step S03, the blowing step S04, and the curing step S05 are performed according to the first part 366 and the second part 367. Thus, the second part 367 connected to the cured first part 366 is formed. In the following description, the description of the same operation as the first embodiment is sometimes omitted. Figure 6 As shown, when the molding of the balancing weight 365 is started, the number of parts Nm molded on the rotating body 12 is 0 (S01). In addition, as described above, the number of parts Na of the balancing weight 365 molded in this embodiment is 2.

[0084] In the first inspection process S02, the operator calculates the position of the balancing weight 365 formed in the rotating body 12, namely the forming position Pm, and the weight of the formed balancing weight 365, namely the forming weight Wb. Then, the operator forms the first part 366 at the forming position Pm. First, in the coating process S03, the operator applies the heated and melted balancing weight to the first surface 61d by the coating device 91. At this time, the weight of the balancing weight applied to the first surface 61d, namely the first weight Wb1, is a weight smaller than the forming weight Wb. The first weight Wb1 is the weight of the first part 366. Then, in the blowing process S04, the operator blows air A to the melted balancing weight by the blowing device 92, so that the melted balancing weight spreads in the second direction D2 along the first surface 61d. Next, when the operator cools the first portion 366 to solidify the first portion 366 in the solidification step S05 , the first portion 366 is molded on the rotating body 12 .

[0085] When the curing step S05 is completed, the number of parts formed on the rotating body 12, that is, Nm, becomes 1 (S06). In addition, as described above, the number of parts Na of the molded balance weight 365 is 2, so next, the operator molds the second part 367 connected to the first part 366 (S07).

[0086] First, in the coating process S03, the operator applies the heated and melted balancing weight to the portion of the first surface 61d that is closer to the other side (-θ side) of the circumferential direction than the first part 366. At this time, the weight of the balancing weight applied to the first surface 61d, that is, the second weight Wb2, is the weight of the difference between the molding weight Wb and the first weight Wb1. The second weight Wb2 is the weight of the second part 367. Next, in the blowing process S04, the operator blows air A to the melted balancing weight through the blowing device 92, so that the melted balancing weight spreads in the second direction D2 along the first surface 61d. Thus, the second part 367 is connected to the first part 366. Next, in the curing process S05, the operator cools the second part 367 to solidify it. Thus, the second part 367 connected to the first part 366 is formed, and the balancing weight 365 is formed on the rotating body 12. When the curing step S05 is completed, the number of parts Nm formed on the rotating body 12 becomes 2 (S06). In addition, as described above, the number of parts Na of the molded balancing weight 365 is 2, so the balancing weight 365 of the predetermined number of parts is molded on the rotating body 12. Therefore, the operator performs the second inspection step S08 (S07).

[0087] In the second inspection step S08, the operator inspects the balance of the rotating body 12 formed with the balancing weight 365. The operations of the steps after the second inspection step S08 in this embodiment are the same as the operations of the steps after the second inspection step S08 in the first embodiment described above. When the balance of the rotating body 12 is within the prescribed specification, the operator finishes the molding of the balancing weight 365.

[0088] According to the present embodiment, the balancing weight 365 includes a first portion 366 and a second portion 367 connected to the first portion 366. The first portion 366 contacts both the first surface 61d and the second surface 61e, and the second portion 367 contacts at least the first surface 61d. When viewed from a direction perpendicular to the first direction D1, the first portion 366, which faces upward, i.e., the first upper surface 366h on one side (+D1 side) of the first direction D1, and the second upper surface 367h on the second portion 367, which faces upward, each have a curved portion convex to the upper side. When a heavy balancing weight 365 is molded on the rotating body 12 by one coating, the time for blowing air A to the melted balancing weight 365 to spread the balancing weight 365 on the rotating body 12 and the time for solidifying the balancing weight 365 are likely to increase. Therefore, the operation man-hours of the blowing step S04 and the operation man-hours of the solidifying step S05 are likely to increase. In contrast, in the present embodiment, the second portion 367 is molded after the first portion 366 is molded, so that the first weight Wb1 of the first portion 366 and the second weight Wb2 of the second portion 367 can be suppressed from increasing. Thus, when the first portion 366 and the second portion 367 are molded, the increase in the number of man-hours of the blowing step S04 and the number of man-hours of the curing step S05 can be suppressed. Therefore, even when a heavy balancing weight 365 is molded, the increase in the number of man-hours of manufacturing the balancing weight 365 can be suppressed.

[0089] In addition, in the present embodiment, the balancing weight 365 has a first contact portion 365e that contacts the first surface 61d of the rotating body 12 and a second contact portion (not shown) that contacts the second surface. Therefore, the contact area between the balancing weight 365 and the rotating body 12 can be increased, so the bonding strength between the balancing weight 365 and the rotating body 12 can be improved. As a result, when the blower 10 is in operation, the balancing weight 365 can be appropriately suppressed from peeling off from the rotating body 12. Therefore, the rotation balance of the rotating body 12 can be appropriately stabilized, so that the rotating body 12 can be stably rotated around the central axis J.

[0090] An embodiment of the present invention has been described above, but the various structures and their combinations in the embodiment are examples, and the addition, omission, replacement and other changes of the structure can be made without departing from the scope of the present invention. In addition, the present invention is not limited to the embodiment. For example, the use of the balancing weight and the blower shown in the above embodiment is not particularly limited.

[0091] The blower may be, for example, a centrifugal fan that blows air radially outward. In this case, the balance of the rotating body can be adjusted by molding a balancing weight on the rotating body, so that the rotating body can be stably rotated around the central axis J.

[0092] The manufacturing method of the balancing weight is not limited to this embodiment. For example, the blowing process and the curing process can also be performed simultaneously. In this case, by making the temperature of the air lower than the melting point of the resin part, the balancing weight can be spread on the first surface, and the balancing weight can be cooled and solidified. Therefore, it is possible to suppress the increase in the manufacturing man-hours of the balancing weight.

[0093] The shape of the balance weight is not limited to the present embodiment, and for example, the dimension in the first direction may be larger than the dimension in the direction perpendicular to the first direction. In addition, when viewed from the direction perpendicular to the first direction, the balance weight may also be in other shapes such as a substantially circular shape.

[0094] In addition, the present technology can adopt the following structures.

[0095] (1) A balancing weight for adjusting the balance of a rotating body capable of rotating about a central axis, the rotating body having a first surface facing a first direction and a second surface facing a second direction intersecting the first direction, wherein the balancing weight has a first contact portion in contact with the first surface and a second contact portion in contact with the second surface, and when viewed from a direction perpendicular to the first direction, the surface of the balancing weight facing the first direction has a curved portion protruding toward the first direction, and the area of ​​the balancing weight projected onto an imaginary plane perpendicular to the first direction is larger than the area of ​​the first contact portion.

[0096] (2) The balance weight according to (1), wherein a dimension of the balance weight in the first direction is smaller than a dimension in a direction perpendicular to the first direction.

[0097] (3) A balancing weight according to (1) or (2), wherein the balancing weight comprises a first part and a second part connected to the first part, the first part contacts both the first surface and the second surface, the second part contacts at least the first surface, and when viewed from a direction perpendicular to the first direction, a surface of the first part facing the first direction and a surface of the second part facing the first direction respectively have a curved portion protruding toward one side of the first direction.

[0098] (4) A balancing weight according to any one of (1) to (3), wherein the rotating body has a first outer side surface facing one side of the first direction and a groove portion recessed from the first outer side surface to the other side of the first direction, the first surface is a surface of the inner side surface of the groove portion facing one side of the first direction, the second surface is a surface of the inner side surface of the groove portion facing a direction perpendicular to the first direction, and the balancing weight is arranged inside the groove portion.

[0099] (5) The balance weight according to (4), wherein the groove portion extends along the entire circumference, and the second surface is a surface facing radially inward.

[0100] (6) The balance weight according to (5), wherein the balance weight is in contact with a third surface of the inner side surface of the groove portion that faces radially outward.

[0101] (7) A blower comprising: a balancing weight as described in any one of (1) to (6); a rotor capable of rotating about a central axis; and an impeller portion connected to the rotor and capable of rotating about the central axis, wherein the rotating body is composed of the rotor and the impeller portion.

[0102] (8) A method for manufacturing a balancing weight, comprising molding a balancing weight on a rotating body for adjusting the balance of the rotating body, the rotating body having a first surface facing a first direction and a second surface facing a second direction intersecting the first direction, and the balancing weight having a first contact portion in contact with the first surface and a second contact portion in contact with the second surface, wherein the method for manufacturing the balancing weight comprises the following steps: a coating step of coating the molten balancing weight on the first surface; a blowing step of blowing air onto the balancing weight coated on the first surface to expand the balancing weight on the rotating body; and a curing step of curing the balancing weight.

Claims

1. A balancing weight for adjusting the balance of a rotating body capable of rotating about a central axis, the rotating body having a first surface facing one side of a first direction and a second surface facing a second direction intersecting the first direction, wherein: The balance weight has a first contact portion in contact with the first surface and a second contact portion in contact with the second surface. When viewed from a direction perpendicular to the first direction, the surface of the balance weight facing the first direction has a curved portion convex toward the first direction. An area of ​​the balance weight projected onto a virtual plane perpendicular to the first direction is larger than an area of ​​the first contact portion.

2. The balancing weight according to claim 1, wherein: The dimension of the balance weight in the first direction is smaller than the dimension in a direction perpendicular to the first direction.

3. The balancing weight according to claim 1, wherein: The balance weight comprises a first part and a second part connected to the first part, The first portion is in contact with both the first surface and the second surface, The second portion at least contacts the first surface, When viewed from a direction perpendicular to the first direction, the surface of the first portion facing the first direction and the surface of the second portion facing the first direction each have a curved portion convex toward the first direction.

4. The balancing weight according to any one of claims 1 to 3, wherein: The rotating body has a first outer side surface facing one side of the first direction and a groove portion recessed from the first outer side surface toward the other side of the first direction. The first surface is a surface of the inner side surface of the groove portion that faces the first direction, and the second surface is a surface of the inner side surface of the groove portion that faces a direction perpendicular to the first direction. The balance weight is disposed inside the groove.

5. The balancing weight according to claim 4, wherein: The groove portion extends along the circumferential direction over the entire circumference. The second surface is a surface facing radially inward.

6. The balancing weight according to claim 5, wherein: The balance weight is in contact with a third surface of the inner side surface of the groove portion that faces radially outward.

7. A blower, comprising: The balancing weight according to any one of claims 1 to 6; a rotor rotatable about a central axis; and The impeller part is connected to the rotor and can rotate around the central axis. The rotating body is composed of the rotor and the impeller part.

8. A method for manufacturing a balancing weight, comprising molding a balancing weight on a rotating body for adjusting the balance of the rotating body, the rotating body having a first surface facing one side of a first direction and a second surface facing a second direction intersecting the first direction, and the balancing weight having a first contact portion contacting the first surface and a second contact portion contacting the second surface, wherein: The manufacturing method of the balancing weight comprises the following steps: A coating step of coating the melted balance weight on the first surface; a blowing step of blowing air toward the balancing weight coated on the first surface so that the balancing weight is spread on the rotating body; as well as a curing step to cure the balancing weight, In the blowing process, air is blown toward the balancing weight so that the shape of the balancing weight becomes a shape in which, when viewed from a direction perpendicular to the first direction, the surface of the balancing weight facing the first direction has a curved portion protruding toward the first direction, and the area of ​​the projection of the balancing weight onto an imaginary plane perpendicular to the first direction is larger than the area of ​​the first contact portion, and the balancing weight is brought into contact with the second surface.

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