Method for manufacturing balance weight, balance weight and blower

Abstract

To provide a method for manufacturing a balance weight that can suppress increase in the number of man-hours in manufacturing a balance weight, and to provide a balance weight and a blower.SOLUTION: A method for manufacturing a balance weight that molds a rotor from a balance weight for adjusting a balance of the rotor includes: a coating application step of applying a molten balance weight to a rotor; a spraying step of spraying air to the balance weight applied to the rotor to spread the balance weight over the rotor; and a setting step of setting the balance weight.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a manufacturing method of a balancing weight, a balancing weight, and a blower. [Background technology]

[0002] 2. Description of the Related Art A motor is known in which unbalanced rotation of a rotor yoke is corrected by applying a balance weight to the rotor yoke (for example, see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2001-298929 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the above-mentioned motor, when the balance weight is applied to the rotor yoke with a spatula or the like, the thickness of the balance weight tends to be large and it is difficult to increase the surface area of ​​the balance weight. Therefore, in the conventional motor, the number of steps required to harden the balance weight tends to increase, and there is a risk that the number of steps required to manufacture the balance weight will increase.

[0005] In view of the above circumstances, an object of one aspect of the present invention is to provide a manufacturing method for a balancing weight, a balancing weight, and a blower that can suppress an increase in the number of steps required for manufacturing the balancing weight. [Means for solving the problem]

[0006] One aspect of the method for manufacturing a balance weight of the present invention is a method for manufacturing a balance weight that adjusts the balance of a rotating body by molding the balance weight onto the rotating body, and includes a coating process for coating the molten balance weight onto the rotating body, a spraying process for blowing air onto the balance weight applied to the rotating body to spread the balance weight over the rotating body, and a hardening process for hardening the balance weight.

[0007] One embodiment of the balance weight of the present invention is a balance weight for adjusting the balance of a rotating body rotatable around a central axis, which is molded on a molding surface of the outer surface of the rotating body facing one side in a first direction, and a central portion in a second direction which is perpendicular to the first direction protrudes to one side in the first direction, and the dimension in the first direction is smaller than the dimension in the second direction.

[0008] One aspect of the blower of the present invention includes the balance weight described above, a rotor rotatable about a central axis, and an impeller portion connected to the rotor and rotatable about the central axis. The rotor and the impeller portion form a rotating body. Effect of the Invention

[0009] According to one aspect of the present invention, in a manufacturing method of a balancing weight, a balancing weight, and a blower, an increase in the number of manufacturing steps for the balancing weight can be suppressed. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a top view showing the blower of the first embodiment. [Diagram 2] FIG. 2 is a cross-sectional view taken along line II-II of FIG. 1, showing the blower of the first embodiment. [Diagram 3] FIG. 3 is a perspective view showing the impeller portion of the first embodiment. [Figure 4] FIG. 4 is a cross-sectional view showing the balance weight of the first embodiment. [Diagram 5]FIG. 5 is a flowchart showing a manufacturing method of the balance weight of the first embodiment. [Figure 6] FIG. 6 is a first cross-sectional view showing a manufacturing method of the balance weight according to the first embodiment. [Figure 7] FIG. 7 is a second cross-sectional view showing the manufacturing method of the balance weight of the first embodiment. [Figure 8] FIG. 8 is a cross-sectional view showing a balance weight according to the second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, a blower according to an embodiment of the present invention will be described with reference to the drawings. Note that the scope of the present invention is not limited to the following embodiment, and can be modified as desired within the scope of the technical concept of the present invention. In addition, in the following drawings, the scale and number of each structure may differ from the actual structure in order to make each structure easier to understand.

[0012] In the following description, the XYZ coordinate system is appropriately shown in the figures as a three-dimensional orthogonal coordinate system. The Z-axis direction indicates the direction in which the central axis J of the rotating body extends. The central axis J shown in each figure is a virtual axis. In the following description, the direction parallel to the Z-axis direction is called the "axial direction". The radial direction centered on the central axis J is simply called the "radial direction". The circumferential direction centered on the central axis J is simply called the "circumferential direction". The side of the axial direction toward which the Z-axis arrow points (+Z side) is called the "upper side". The opposite side of the axial direction to the side toward which the Z-axis arrow points (-Z side) is called the "lower side". Note that the upper side and the lower side are names simply for explaining the relative positional relationship of each part, and the actual positional relationship, etc. may be a positional relationship, etc. other than the positional relationship, etc. indicated by these names. The X-axis direction is a direction perpendicular to the Z-axis direction. The Y-axis direction is a direction perpendicular to both the Z-axis direction and the X-axis direction. In each figure, the circumferential direction is indicated by an arrow θ.

[0013] The first direction D1, which is appropriately shown in each figure, is the direction in which the molding surface of the rotor faces. In this embodiment, the molding surface is the surface on which the balance weight is molded. In this embodiment, the first direction D1 is a direction parallel to the axial direction. The first direction D1 may be a direction intersecting with the axial direction. In the following description, the side to which the arrow of the first direction D1 faces (+D1 side) is called "one side of the first direction D1", and the opposite side to the side to which the arrow of the first direction D1 faces (-D1 side) is called "the other side of the first direction D1". The second direction D2, which is appropriately shown in each figure, is a direction intersecting with the first direction D1. In this embodiment, the second direction D2 is a direction perpendicular to the first direction D1.

[0014] First Embodiment The blower 10 of this embodiment shown in Fig. 1 is used, for example, as an electric cooling fan for cooling electronic devices. The blower 10 of this embodiment is an axial flow fan that blows air in the axial direction. As shown in Fig. 2, the blower 10 includes a motor 15, a housing 50, an impeller portion 60, and a balance weight 65. The blower 10 also includes a rotor 12.

[0015] The impeller portion 60 is rotatable about the central axis J. The impeller portion 60 has an impeller cup 61 and a plurality of blade portions 62. The impeller cup 61 is substantially cylindrical and extends in the axial direction about the central axis J. The impeller cup 61 opens downward. The motor 15 is housed inside the impeller cup 61. The impeller cup 61 has a first outer surface 61a, a groove portion 61c, and a molding surface 61d.

[0016] The first outer surface 61a is a surface of the outer surface of the impeller part 60 facing one side (+D1 side) in the first direction D1. As shown in FIG. 3, the first outer surface 61a is substantially circular with the center on the central axis J when viewed in the axial direction. The groove portion 61c is a groove recessed from the first outer surface 61a to the other side (-D1 side) in the first direction D1. When viewed in the axial direction, the groove portion 61c is annular with the center on the central axis J. The groove portion 61c extends around the circumference in the circumferential direction. The molding surface 61d is a surface of the outer surface of the impeller part 60 facing one side in the first direction D1. In this embodiment, the molding surface 61d is a surface of the inner surface of the groove portion 61c facing one side in the first direction D1. When viewed in the axial direction, the molding surface 61d is annular. The molding surface 61d extends around the circumference.

[0017] Each of the multiple blade portions 62 protrudes radially outward from the outer circumferential surface of the impeller cup 61. As shown in Fig. 1, the impeller portion 60 has five blade portions 62. The blade portions 62 are arranged side by side in the circumferential direction along the outer circumferential surface of the impeller cup 61. When the impeller portion 60 rotates around the central axis J, each blade portion 62 blows air in the axial direction.

[0018] As shown in FIG. 2, the housing 50 accommodates the motor 15 and the impeller portion 60 therein. The housing 50 holds the motor 15 and the impeller portion 60. The housing 50 has a peripheral wall portion 51 and a motor holding portion 55. As shown in FIGS. 1 and 2, the peripheral wall portion 51 is in the shape of a square tube extending in the axial direction. As shown in FIG. 2, the peripheral wall portion 51 surrounds the impeller portion 60 and the motor 15 from the radially outer side. The motor holding portion 55 is in the shape of a cylinder extending in the axial direction with the central axis J as the center. The motor holding portion 55 is disposed inside the impeller cup 61.

[0019] The motor 15 is accommodated 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 this embodiment is an outer rotor motor in which the rotor 20 is disposed radially outside the stator 30. The rotor 20 is rotatable about the central axis J. The rotor 20 is held on the inner peripheral surface of the impeller cup 61. This allows the impeller portion 60 to be connected to the rotor 20. When the rotor 20 rotates about the central axis J, the impeller portion 60 rotates about the central axis J. The rotor 20 has a magnet 22.

[0020] The shaft 23 is cylindrical and extends in the axial direction around the central axis J. The shaft 23 is disposed inside the motor holding portion 55. An upper portion of the shaft 23 is rotatably held by the first bearing 24a. A lower portion of the shaft 23 is rotatably held by the second bearing 24b. The first bearing 24a and the second bearing 24b are each held on the inner circumferential surface of the motor holding portion 55. This allows the shaft 23 to rotate around the central axis J. The rotor bearing 25 is substantially cylindrical and centered on the central axis J. The shaft 23 is inserted in the axial direction into the rotor bearing 25. A portion of the shaft 23 including the upper end is fitted into the rotor bearing 25. The rotor bearing 25 supports the rotor 20 to rotate around the central axis J.

[0021] The stator 30 is annular and surrounds the central axis J. The stator 30 is disposed inside the rotor 20. The stator 30 faces the magnets 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.

[0022] The stator core 31 is annular around the central axis J. The stator core 31 has a core back portion 32 and a plurality of teeth portions 33. The core back portion 32 is annular about the central axis J. The core back portion 32 is fixed to the outer peripheral surface of the motor holding portion 55. Each tooth portion 33 protrudes radially outward from the outer peripheral surface of the core back portion 32. Although not shown, each tooth portion 33 is disposed at intervals along the outer peripheral surface of the core back portion 32. The insulator 40 insulates the stator core 31 from the coil portion 35. The insulator 40 is attached to the stator core 31.

[0023] The connection pins 80 are columnar and extend in the axial direction. The connection pins 80 are conductive. Although not shown in the figure, the stator 30 has two connection pins 80. Each connection pin 80 is held by the insulator 40. Although not shown in the figure, the lower end of each connection pin 80 is connected to the circuit board 70.

[0024] The coil portion 35 is electrically connected to the circuit board 70 via the connection pin 80. When a current is supplied to the coil portion 35 from the circuit board 70, a rotational torque is generated in the rotor 20 by a magnetic force between the magnetic poles of the electromagnets formed by the stator 30 and the magnets 22. The coil portion 35 has a plurality of coil main body portions 36 and coil lead wires 38.

[0025] Each coil body 36 is attached to a different tooth portion 33 of the stator core 31 via an insulator 40. The coil lead wires 38 are drawn out from the coil body 36. Although not shown, in this embodiment, the stator 30 has two coil lead wires 38. Each coil lead wire 38 is connected to a different connection pin 80. As a result, the coil portion 35 is electrically connected to the circuit board 70 via the connection pins 80.

[0026] The circuit board 70 is disposed below the stator core 31. The circuit board 70 is in the form of a plate extending in a direction perpendicular to the axial direction. As described above, the circuit board 70 is connected to the connection pins 80. The circuit board 70 supplies a current to the coil portion 35 via the connection pins 80.

[0027] In this embodiment, the rotating body 12 is a member that can rotate around the central axis J among the various members included in the blower 10. In this embodiment, the rotating body 12 is configured by an impeller portion 60 and a rotor 20. In this embodiment, a balance weight 65 is molded in the rotating body 12. In this embodiment, as will be described later, the balance weight 65 is molded in the impeller portion 60. The balance weight 65 may be molded in the rotor 20, or may be molded in each of the impeller portion 60 and the rotor 20.

[0028] As shown in FIG. 3, the balance weight 65 is disposed inside the groove 61c of the impeller portion 60. As shown in FIG. 4, the balance weight 65 is molded on the molding surface 61d. In this embodiment, the balance weight 65 is a weight for adjusting the balance of the rotor 12. The balance weight 65 of this embodiment is composed of one molding layer. The number of layers Na of the balance weight 65 of this embodiment is 1. By molding the balance weight 65 of a predetermined weight at a predetermined position in the circumferential direction of the molding surface 61d, the deviation of the center of gravity position of the rotor 12 with respect to the central axis J can be reduced. This allows the rotor 12 to rotate stably around the central axis J. Note that the impeller portion 60 does not need to have the groove 61c, and in this case, the balance weight 65 may be molded on the first outer surface 61a. The balance weight 65 may also be molded on the rotor 20. For example, when the balance weight 65 is formed on a surface facing the radial direction of the rotor 20, the first direction D1 is a direction perpendicular to the axial direction, and the second direction D2 is a direction perpendicular to the radial direction.

[0029] In this embodiment, the balance weight 65 includes a metal powder 65b and a resin portion 65a containing the powder 65b. The powder 65b may be made of a metal such as tungsten or stainless steel. The resin portion 65a is made of a resin having thermoplastic properties. The resin portion 65a may be made of a thermoplastic resin such as polyethylene, polypropylene, or polyvinyl chloride.

[0030] The balance weight 65 of this embodiment has a mountain shape that protrudes from the molding surface 61d to one side (+D1 side) in the first direction D1. More specifically, the dimension L1 of the balance weight 65 in the first direction D1 is smaller than the dimension L2 in the second direction D2. The center part of the balance weight 65 in the second direction D2 protrudes to one side in the first direction D1. The part of the balance weight 65 on one side in the first direction D1 is a flat surface that is narrow in the second direction D2. The balance weight 65 has a curved surface shape with a base that widens in the second direction D2. As shown in FIG. 3, the surface of the balance weight 65 facing one side in the first direction D1 is disposed at a distance from the first outer surface 61a.

[0031] Next, a manufacturing method Mb of the balance weight 65 of this embodiment will be described. In the manufacturing method Mb of the balance weight 65, the balance weight 65 is molded on the rotating body 12. As shown in FIG. 5, the manufacturing method Mb of the balance weight 65 of this embodiment includes a first inspection step S02 for inspecting the balance of the rotating body 12, a coating step S03 for coating the molten balance weight 65 on the rotating body 12, a spraying step S04 for blowing air A onto the balance weight 65 applied to the rotating body 12 to spread the balance weight 65 on the rotating body 12, a hardening step S05 for hardening the balance weight 65, and a second inspection step S08 for inspecting the balance of the rotating body 12 on which the balance weight 65 is molded. In the following description, "workers, etc." includes workers who perform each task and assembly equipment, etc. Each task may be performed only by a worker, only by an assembly equipment, or by a worker and an assembly equipment.

[0032] When starting the molding of the balance weight 65, the number of layers Nm of the molded layers molded on the rotor 21 is 0 (S01). As described above, the number of layers Na of the balance weight 65 in this embodiment is 1. In the first inspection step S02, the balance of the rotor 12 is inspected. Although not shown, an operator measures the amount of deviation of the center of gravity of the rotor 12 with respect to the central axis J using a known balance measuring device. The balance measuring device may measure the amount of deviation by rotating the rotor 12, or may measure the amount of deviation while the rotor 12 is stationary. From the amount of deviation, an operator calculates a molding position Pm, which is a position where the balance weight 65 is molded, and a molding weight Wb, which is the weight of the balance weight 65 to be molded. When the molding position Pm and the molding weight Wb are calculated, the first inspection step S02 is completed. The molding position Pm and the molding weight Wb may be calculated by the balance measuring device. In this embodiment, the molding position Pm is a part of the molding surface 61d. The molding position Pm may be a part of the impeller portion 60 other than the molding surface 61d, or may be a part of the rotor 20.

[0033] In the application step S03, the molten balance weight 65 is applied to the rotor 12. As shown in FIG. 6, in the application step S03, an operator applies the heated and melted balance weight 65 to the molding surface 61d by using an application device 91 arranged on one side (+D1 side) of the impeller unit 60 in the first direction D1. In this embodiment, the balance weight 65 contains powder 65b, so the melted balance weight 65 is in a paste form. In this embodiment, the application device 91 is a dispenser capable of discharging a predetermined weight of the melted balance weight 65. Therefore, the difference between the weight of the melted balance weight 65 applied to the rotor 12 and the molding weight Wb can be reduced. In addition, the application device 91 is connected to the inside of a container having a heating means such as a heater (not shown). The balance weight 65 heated and melted by the heating means is accommodated inside the container. The melted balance weight 65 inside the container is supplied to the application device 91. When the molten balance weight 65 having the molding weight Wb is applied to the molding position Pm of the molding surface 61d by the application device 91, the application step S03 is completed.

[0034] Since the molten balance weight 65 has a certain degree of viscosity, the shape of the balance weight 65 applied to the molding surface 61d is substantially spherical, as shown in FIG. 7. In addition, a protruding portion 65c protruding to one side (+D1 side) of the first direction D1 is formed on the surface of the balance weight 65. In this embodiment, the dimension L3 in the first direction D1 of the balance weight 65 applied to the molding surface 61d is larger than the dimension L4 in the second direction D2. In addition, the dimension L3 in the first direction D1 of the balance weight 65 applied to the molding surface 61d is larger than the dimension in the first direction D1 of the groove portion 61c. Note that the dimension L3 in the first direction D1 of the balance weight 65 applied to the molding surface 61d may be smaller than the dimension L4 in the second direction D2, and the dimension L3 in the first direction D1 of the balance weight 65 may be smaller than the dimension in the first direction D1 of the groove portion 61c.

[0035] In the spraying step S04, air A is sprayed onto the balance weight 65 applied to the rotor 12, and the balance weight 65 is spread over the rotor 12. In the spraying step S04, an operator or the like uses a spraying device 92 disposed on one side (+D1 side) of the impeller portion 60 in the first direction D1 to spray air A onto the balance weight 65 from one side in the first direction D1. The air A is compressed air compressed by a compressor (not shown). In this embodiment, the temperature of the air A is higher than the melting point of the resin portion 65a of the balance weight 65. The temperature of the air A may be lower than the melting point of the resin portion 65a of the balance weight 65.

[0036] The melted balance weight 65 spreads in the second direction D2 along the molding surface 61d due to the wind pressure of the air A. The protruding portion 65c is taken into the melted balance weight 65 due to the wind pressure of the air A. As a result, the balance weight 65 becomes a mountain shape as shown in FIG. 4. More specifically, the dimension L1 of the balance weight 65 in the first direction D1 is smaller than the dimension L2 in the second direction D2. The center of the balance weight 65 in the second direction D2 protrudes to one side (+D1 side) of the first direction D1. The portion of the balance weight 65 on one side in the first direction D1 becomes a narrow flat surface in the second direction D2. The balance weight 65 becomes a curved surface with a base that spreads out in the second direction D2. The end of the balance weight 65 on one side in the first direction D1 is located on the other side (-D1 side) of the first direction D1 from the first outer surface 61a. When the balance weight 65 is spread over the rotor 12, the spraying step S04 ends.

[0037] In the hardening step S05, the balance weight 65 is hardened. In the hardening step S05, the worker or the like hardens the balance weight 65 by cooling the molten balance weight 65. The cooling of the balance weight 65 may be performed in a room temperature atmosphere, or may be performed in a low temperature atmosphere by storing the rotor 12 in a cooling furnace (not shown). The hardening step S05 may also serve as the spraying step S04. When the balance weight 65 is hardened, the hardening step S05 ends. Note that, in this embodiment, the worker or the like ends the hardening step S05 before the balance weight 65 is completely hardened. More specifically, the worker or the like ends the hardening step S05 when the balance weight 65 is hardened to a degree that allows the shape shown in FIG. 4 to be maintained even if the rotor 12 is subjected to vibration. Note that the worker or the like may end the hardening step S05 after the balance weight 65 is completely hardened.

[0038] 5, when the hardening step S05 is completed, the number of layers Nm of the molded layers formed on the rotor 21 becomes 1 (S06). As described above, the number of layers Na of the balance weight 65 to be molded is 1, so that a predetermined number of layers of the balance weight 65 are formed on the rotor 21. Therefore, the worker or the like performs the second inspection step S08 (S07).

[0039] In the second inspection step S08, the balance of the rotating body 12 on which the balance weight 65 is molded is inspected. The worker measures the amount of deviation of the center of gravity position from the central axis J of the rotating body 12 on which the balance weight 65 is molded, using the balance measuring device (not shown) or the like. If the amount of deviation between the center of gravity position of the rotating body 12 and the central axis J is equal to or less than a predetermined amount, that is, if the balance of the rotating body 12 is within a predetermined standard (S09), the worker ends the manufacture of the balance weight 65. If the balance of the rotating body 12 is outside the predetermined standard (S09), the worker molds the balance weight 65 with the molding weight Wb at the newly calculated molding position Pm (S03 to S06), and then performs the second inspection step S08. The workers etc. repeat the second inspection process S08 and the molding of the balance weight 65 until the balance of the rotating body 12 falls within the predetermined standard, and when the balance of the rotating body 12 falls within the predetermined standard, the workers etc. terminate the manufacture of the balance weight 65 (S09).

[0040] The manufacturing method Mb of the balance weight of this embodiment includes a coating step S03 of coating the molten balance weight 65 on the rotor 12, a spraying step S04 of spraying the air A onto the balance weight 65 coated on the rotor 12 to spread the balance weight 65 on the rotor 12, and a hardening step S05 of hardening the balance weight 65. Thus, the balance weight 65, which is substantially spherical when coated on the rotor 12 in the coating step S03, can be spread in the second direction D2 in the spraying step S04, so that the surface area of ​​the balance weight 65 can be increased. This increases the amount of heat dissipated from the surface of the balance weight 65 to the atmosphere and the rotor 12 in the hardening step S05, so that the time required to cool the balance weight 65 can be shortened. This shortens the time required for the balance weight 65 to harden, so that the number of steps required to manufacture the balance weight 65 can be suppressed from increasing.

[0041] In addition, as described above, since the balance weight 65 can be spread over the rotor 12 in the spraying step S04, the contact area between the balance weight 65 and the rotor 12 can be increased. This can increase the adhesive strength between the balance weight 65 and the rotor 12. Therefore, during operation of the blower 10, the balance weight 65 can be prevented from peeling off from the rotor 12 due to the centrifugal force applied to the balance weight 65 when the rotor 12 rotates around the central axis J. Therefore, the rotation balance of the rotor 12 can be suitably stabilized, and the rotor 12 can be stably rotated around the central axis J. This can suppress vibration and noise when the blower 10 operates. In addition, the force applied to the rotor bearing 25 supporting the rotor 20, i.e., the rotor 12, can be prevented from increasing, and deterioration of the rotor bearing 25 due to wear and the like can be suppressed.

[0042] In this embodiment, since the air A is blown in the blowing step S04 to the protrusion 65c formed on the surface of the balance weight 65 in the application step S03, the protrusion 65c can be taken into the balance weight 65 as described above. Therefore, when the blower 10 is operating, the protrusion 65c can be prevented from coming off the balance weight 65, and therefore, for example, the protrusion 65c can be prevented from being caught between the rotor 20 and the stator 30. Therefore, the stability of the operation of the blower 10 can be improved.

[0043] Furthermore, when the balance weight 65 is spread on the rotor 12 with a member such as a spatula, a part of the paste-like balance weight 65 is likely to adhere to the member such as the spatula, making it difficult to stabilize the weight of the balance weight 65 formed on the rotor 12. In contrast, in the present embodiment, the balance weight 65 is spread on the rotor 12 by air A in the spraying step S04, so that the weight of the balance weight 65 can be suitably stabilized. Therefore, the balance of the rotor 12 can be adjusted with high precision, so that the rotor 12 can be rotated more stably around the central axis J. Therefore, vibration and noise during operation of the blower 10 can be more suitably suppressed, and deterioration of the rotor bearing 25 can be more suitably suppressed.

[0044] According to this embodiment, the balance weight 65 includes the metal powder 65b and the resin part 65a that has thermoplasticity and contains the powder 65b. Therefore, the specific gravity of the balance weight 65 can be increased compared to the case where the balance weight 65 does not include the metal powder 65b. This makes it possible to reduce the volume of the balance weight 65 molded on the rotating body 12, thereby suppressing increases in the time required to apply the balance weight 65 to the rotating body 12 in the application step S03 and the time required to harden the balance weight 65 in the hardening step S05. Therefore, it is possible to suppress an increase in the number of steps required to manufacture the balance weight 65.

[0045] In this embodiment, since the temperature of the air A is higher than the melting point of the resin portion 65a as described above, it is possible to prevent the temperature of the resin portion 65a from decreasing and the viscosity of the resin portion 65a from increasing when the air A is blown onto the balance weight 65 in the blowing step S04. Therefore, the balance weight 65 can be easily spread over the rotating body 12 in the blowing step S04.

[0046] According to this embodiment, the rotating body 12 is composed of the rotor 20 and the impeller portion 60 included in the blower 10. Therefore, the rotor 20 can be rotated stably around the central axis J, and therefore the radial position of the rotor 20 relative to the stator 30 can be prevented from fluctuating. Therefore, the magnetic force between the magnetic poles of the electromagnets formed by the stator 30 and the magnets 22 of the rotor 20 can be prevented from fluctuating, and therefore the rotation speed and rotation torque of the rotor 20 and the impeller portion 60 can be stabilized. This allows the operation of the blower 10 to be stabilized.

[0047] According to this embodiment, the balance weight 65 is molded on the molding surface 61d of the outer surface of the rotor 12 facing one side (+D1 side) in the first direction D1, and the center part in the second direction D2 protrudes to one side in the first direction D1, and the dimension L1 in the first direction D1 is smaller than the dimension L2 in the second direction D2. Therefore, since it is easy to reduce the dimension of the balance weight 65 in the first direction D1, i.e., the dimension in the height direction of the balance weight 65, it is possible to suppress an increase in air resistance applied to the balance weight 65 when the rotor 12 rotates. Therefore, the rotor 12 can be stably rotated around the central axis J, and the driving efficiency of the blower 10 can be improved.

[0048] In addition, in this embodiment, as described above, the dimension L1 of the balance weight 65 in the first direction D1 is smaller than the dimension in the second direction D2, so that the surface area of ​​the balance weight 65 can be increased. As a result, as described above, the time required for the balance weight 65 to harden can be shortened in the hardening step S05. Therefore, an increase in the number of steps required for manufacturing the balance weight 65 can be suppressed. As described above, the contact area between the balance weight 65 and the rotating body 12 can be increased, so that the adhesive strength between the balance weight 65 and the rotating body 12 can be increased. As a result, the balance weight 65 can be prevented from peeling off from the rotating body 12 when the rotating body 12 rotates around the central axis J.

[0049] According to this embodiment, the portion of the balance weight 65 on one side (+D1 side) in the first direction D1 is a flat surface that is narrow in the second direction D2, and is a curved surface that widens at the bottom. Therefore, compared to a case in which the balance weight 65 has a protruding portion 65c that protrudes to one side in the first direction D1, the air resistance applied to the balance weight 65 when the rotor 12 rotates can be more suitably reduced. Therefore, the rotor 12 can be more stably rotated around the central axis J, and the drive efficiency of the blower 10 can be more suitably improved.

[0050] According to this embodiment, the rotor 12 has a first outer surface 61a facing one side (+D1 side) of the first direction D1, and a groove portion 61c recessed from the first outer surface 61a to the other side (-D1 side) of the first direction D1, and the molding surface 61d is a surface facing one side of the first direction D1 among the inner surfaces of the groove portion 61c, and the surface of the balance weight 65 facing one side of the first direction D1 is disposed at a distance from the first outer surface 61a. Therefore, since the balance weight 65 is easily disposed inside the groove portion 61c, the air resistance applied to the balance weight 65 when the rotor 12 rotates can be more suitably reduced. Therefore, the rotor 12 can be more suitably and stably rotated around the central axis J, and the driving efficiency of the blower 10 can be more suitably increased.

[0051] According to this embodiment, the groove 61c extends around the circumference in the circumferential direction. When applying the balance weight 65 to the inside of the groove 61c with a member such as a spatula, a rib may be provided inside the groove 61c to scrape off the balance weight 65 from the member such as the spatula. In contrast, in this embodiment, the balance weight 65 is applied to the molding surface 61d by the application device 91 as described above. Therefore, even if the groove 61c extends around the circumference, that is, the groove 61c is not provided with a rib, the balance weight 65 can be easily applied to the molding surface 61d. Therefore, in this embodiment, the shape of the groove 61c can be simplified, and therefore the structure of the mold used to mold the impeller portion 60 can be simplified. Therefore, the manufacturing cost of the mold can be prevented from increasing.

[0052] According to this embodiment, the blower 10 includes the balance weight 65, the rotor 20 rotatable about the central axis J, and the impeller unit 60 connected to the rotor 20 and rotatable about the central axis J, and the rotor 12 is configured by the rotor 20 and the impeller unit 60. Therefore, as described above, the surface area of ​​the balance weight 65 can be increased in the spraying step S04, and therefore the time required for the balance weight 65 to harden in the hardening step S05 can be shortened. Therefore, an increase in the number of steps required for manufacturing the balance weight 65 can be suppressed, and therefore an increase in the number of steps required for manufacturing the blower 10 can be suppressed.

[0053] <Second embodiment> 8, a balance weight 265 included in the blower 210 of this embodiment is composed of a plurality of molding layers 266, 267 laminated on the rotor 12. In the following description, the same components as those in the first embodiment described above are denoted by the same reference numerals, and the description thereof will be omitted.

[0054] The balance weight 265 has a mountain shape that protrudes from the molding surface 61d to one side (+D1 side) in the first direction D1. More specifically, the dimension L1 of the balance weight 265 in the first direction D1 is smaller than the dimension L2 in the second direction D2. The center part of the balance weight 265 in the second direction D2 protrudes to one side in the first direction D1. The part of the balance weight 265 on one side in the first direction D1 is a flat surface that is narrow in the second direction D2. The balance weight 265 has a curved surface shape with a bottom that spreads out in the second direction D2. Although not shown in the figure, the surface of the balance weight 265 facing one side in the first direction D1 is disposed at a distance from the first outer surface 61a. The balance weight 265 of this embodiment is composed of two molding layers 266, 267. The number of layers Na of the balance weight 265 of this embodiment is 2. The balance weight 265 may be composed of three or more molded layers. The balance weight 265 of the present embodiment is composed of a first molded layer 266 and a second molded layer 267.

[0055] The first molding layer 266 is molded on the molding surface 61d. The first molding layer 266 has a mountain shape that protrudes from the molding surface 61d to one side in the first direction D1 (+D1 side). The second molding layer 267 is formed on the first molding layer 266. The second molding layer 267 has a mountain shape that protrudes from the first molding layer 266 to one side in the first direction D1. The second molding layer 267 is connected to the first molding layer 266 in the first direction D1.

[0056] Next, a manufacturing method Mb of the balance weight 265 of this embodiment will be described. In this embodiment, the above-mentioned coating step S03, spraying step S04, and hardening step S05 are performed for each of the multiple molded layers 266, 267. As a result, the second molded layer 267 is molded on the hardened first molded layer 266. In the following description, the same operations as those in the first embodiment may be omitted. As shown in FIG. 5, when starting to mold the balance weight 265, the number of layers Nm of the molded layers molded on the rotor 21 is 0 (S01). Also, as described above, the number of layers Na of the balance weight 265 molded in this embodiment is 2.

[0057] In the first inspection step S02, the worker calculates the molding position Pm, which is the position on the rotor 12 where the balance weight 265 is molded, and the molding weight Wb, which is the weight of the balance weight 265 to be molded. Next, the worker molds the first molded layer 266 on the molding surface 61d. First, in the application step S03, the worker applies the heated and melted balance weight to the molding surface 61d by the application device 91. At this time, the first weight Wb1, which is the weight of the balance weight applied to the molding surface 61d, is smaller than the molding weight Wb. The first weight Wb1 is the weight of the first molded layer 266. Next, in the blowing step S04, the worker blows air A onto the melted balance weight by the blowing device 92, and spreads the melted balance weight in the second direction D2 along the molding surface 61d. As a result, the first molded layer 266 becomes a mountain shape as shown in FIG. 8. Next, in a hardening step S05, the worker or the like hardens the first molded layer 266 by cooling it, whereby the first molded layer 266 is molded onto the rotor 12.

[0058] When the hardening step S05 is completed, the number of layers Nm of the molded layers formed on the rotor 21 becomes 1 (S06). As described above, the number of layers Na of the balance weight 65 to be molded is 2, so next, the worker or the like molds the second molded layer 267 on the first molded layer 266 (S07).

[0059] First, in the application step S03, the worker applies the heated and melted balance weight onto the hardened first molded layer 266. At this time, the second weight Wb2, which is the weight of the balance weight applied onto the first molded layer 266, is the weight of the difference between the molded weight Wb and the first weight Wb1. The second weight Wb2 is the weight of the second molded layer 267. Next, in the blowing step S04, the worker blows air A onto the melted balance weight using the blowing device 92, spreading the melted balance weight in the second direction D2 along the surface of the first molded layer 266. As a result, the second molded layer 267 becomes a mountain shape as shown in FIG. 8. Next, in the hardening step S05, the worker hardens the second molded layer 267 by cooling it. As a result, the second molded layer 267 is molded onto the first molded layer 266, and the balance weight 265 is molded on the rotating body 12. 5, when the hardening step S05 is completed, the number of layers Nm of the molded layers formed on the rotor 21 becomes 2 (S06). As described above, the number of layers Na of the balance weight 265 to be molded is 2, so that a predetermined number of layers of the balance weight 65 are formed on the rotor 21. Therefore, the worker or the like performs the second inspection step S08 (S07).

[0060] In the second inspection step S08, the worker inspects the balance of the rotating body 12 on which the balance weight 265 is molded. If the balance of the rotating body 12 is within a predetermined standard (S09), the worker ends the manufacture of the balance weight 265. If the balance of the rotating body 12 is not within the predetermined standard (S09), the worker molds a balance weight with a molding weight Wb at a newly calculated molding position Pm (S03 to S05), and then performs the second inspection step S08. The worker repeats the second inspection step S08 and the molding of the balance weight 265 until the balance of the rotating body 12 is within the predetermined standard. If the balance of the rotating body 12 is within the predetermined standard, the worker ends the manufacture of the balance weight 265.

[0061] If the molding weight Wb of the balance weight 265 calculated in the first inspection step S02 exceeds the weight that can be molded at one time, the molding of the balance weight 265 may be performed without performing the second inspection step S08. If the balance weight 265 is composed of three or more molding layers, the number of layers Na of the balance weight 265 to be molded is set to the number of layers of the balance weight 265, and the coating step S03, the spraying step S04, and the hardening step S05 are performed for each molding layer. In this way, the balance weight 265 in which three or more molding layers are stacked on the rotating body 12 can be molded.

[0062] According to this embodiment, the balance weight 265 is composed of a plurality of molded layers 266, 267 stacked on the rotating body 12, and the application step S03, the spraying step S04, and the hardening step S05 are performed for each of the molded layers 266, 267 to mold the molded layer 267 on the hardened molded layer 266. When a heavy balance weight 265 is molded on the rotating body 12 by a single application, the time required to blow air A onto the molten balance weight 265 to spread the balance weight 265 in the second direction D2 and the time required to harden the balance weight 265 tend to increase. Therefore, the number of steps in the spraying step S04 and the hardening step S05 tend to increase. In contrast, in this embodiment, since the first molded layer 266 is molded on the rotor 12 and then the second molded layer 267 is molded on the first molded layer 266, it is possible to suppress an increase in each of the first weight Wb1 of the first molded layer 266 and the second weight Wb2 of the second molded layer 267. This makes it possible to suppress an increase in the number of steps in the spraying step S04 and the hardening step S05 when molding each of the first molded layer 266 and the second molded layer 267. Therefore, even when molding a heavy balance weight 265, it is possible to suppress an increase in the number of steps in manufacturing the balance weight 265.

[0063] According to this embodiment, the balance weight 265 is composed of a plurality of molded layers 266, 267 stacked on the rotor 12. Therefore, as described above, when molding the first molded layer 266 and the second molded layer 267, it is possible to suppress an increase in the number of steps in the spraying step S04 and the hardening step S05. Therefore, even when molding a heavy balance weight 265, it is possible to suppress an increase in the number of steps in manufacturing the balance weight 265.

[0064] Although one embodiment of the present invention has been described above, each configuration and their combination in the embodiment is merely an example, and addition, omission, substitution and other modifications of the configuration are possible without departing from the spirit of the present invention. Furthermore, the present invention is not limited to the embodiment. For example, the uses of the balance weight, motor and blower shown in the above embodiment are not particularly limited.

[0065] The blower may be, for example, a centrifugal fan that blows air radially outward. Even in this case, by forming a balance weight on the rotor, it is possible to reduce the deviation of the center of gravity of the rotor from the central axis J, so that the rotor can rotate stably around the central axis J.

[0066] The manufacturing method of the balance weight is not limited to this embodiment, and for example, the spraying step and the curing step may be performed simultaneously. In this case, the balance weight can be cooled and cured while spreading on the molding surface by setting the air temperature lower than the melting point of the resin part. Therefore, the number of steps required for manufacturing the balance weight can be more appropriately suppressed.

[0067] The present technology can be configured as follows. (1) A method for manufacturing a balance weight, which adjusts the balance of a rotating body, by molding the balance weight onto the rotating body, the method including: a coating process for coating the molten balance weight onto the rotating body; a spraying process for blowing air onto the balance weight applied to the rotating body to spread the balance weight over the rotating body; and a hardening process for hardening the balance weight. (2) The method for manufacturing a balance weight according to (1), wherein the balance weight includes a metal powder and a resin part having thermoplastic properties and containing the powder. (3) A method for manufacturing a balance weight according to (1) or (2), wherein the balance weight is composed of a plurality of molded layers stacked on the rotating body, and a molded layer is molded on the hardened molded layer by carrying out the coating process, the spraying process, and the curing process for each molded layer. (4) The method for manufacturing a balance weight according to any one of (1) to (3), wherein the rotating body is constituted by a rotor and an impeller portion provided in a blower fan. (5) A balance weight for adjusting the balance of a rotating body rotatable around a central axis, the balance weight being molded on a molding surface of the outer surface of the rotating body facing one side in a first direction, the central portion in a second direction which is perpendicular to the first direction protruding to one side in the first direction, and the dimension in the first direction being smaller than the dimension in the second direction. (6) A balance weight as described in (5), wherein the portion on one side in the first direction is flat and narrow in the second direction, and is curved and flared at the bottom. (7) A balance weight according to (5) or (6), which is constituted by a plurality of molded layers laminated on the rotating body. (8) A balance weight described in any one of (5) to (7), wherein the rotating body has a first outer surface facing one side in the first direction and a groove portion recessed from the first outer surface to the other side in the first direction, the molding surface is a surface of the inner surface of the groove portion facing one side in the first direction, and the surface of the balance weight facing one side in the first direction is positioned at a distance from the first outer surface. (9) The balance weight according to (8), wherein the groove portion extends around the entire circumference in the circumferential direction. (10) A blower comprising: a balance weight according to any one of (5) to (9); a rotor rotatable about a central axis; and an impeller portion connected to the rotor and rotatable about the central axis, wherein the rotating body is constituted by the rotor and the impeller portion. [Explanation of symbols]

[0068] 10,210...blower, 12...rotating body, 20...rotor, 60...impeller portion, 61a...first outer surface, 61c...groove portion, 61d...molding surface, 65,265...balance weight, 65a...resin portion, 65b...powder, 266,267...molding layer, A...air, D1...first direction, D2...second direction, J...central axis, S03...coating process, S04...spraying process, S05...curing process

Claims

1. A method for manufacturing a balance weight, which adjusts the balance of a rotating body, by molding the balance weight on the rotating body, comprising the steps of: a coating step of coating the molten balance weight onto the rotating body; a blowing step of blowing air onto the balance weight applied to the rotating body to spread the balance weight over the rotating body; a hardening step of hardening the balance weight; A method for manufacturing a balance weight, comprising:

2. 2. The method for manufacturing a balancing weight according to claim 1, wherein the balancing weight includes a metal powder and a resin part having thermoplastic properties and containing the powder.

3. The balance weight is composed of a plurality of molding layers laminated on the rotating body, 2. The method for manufacturing a balance weight according to claim 1, wherein the coating step, the spraying step, and the curing step are performed for each molding layer, thereby molding a molding layer on a hardened molding layer.

4. The method for manufacturing a balance weight according to claim 1 , wherein the rotating body is constituted by a rotor and an impeller portion of a blower fan.

5. A balance weight for adjusting the balance of a rotating body that can rotate around a central axis, The molded surface is a molding surface of the outer surface of the rotating body that faces one side in the first direction, A central portion in a second direction perpendicular to the first direction protrudes to one side in the first direction, A balance weight, the dimension in the first direction being smaller than the dimension in the second direction.

6. 6. The balance weight according to claim 5, wherein the portion on one side in the first direction is a flat surface that is narrow in the second direction and is a curved surface that widens toward the bottom.

7. 6. The balance weight according to claim 5, which is constituted by a plurality of molded layers laminated on the rotor.

8. the rotating body has a first outer surface facing one side in the first direction and a groove portion recessed from the first outer surface to the other side in the first direction, the molding surface is a surface of an inner surface of the groove portion facing one side in the first direction, The balance weight according to claim 5 , wherein a surface of the balance weight facing one side in the first direction is disposed at a distance from the first outer surface.

9. The balance weight according to claim 8 , wherein the groove portion extends around the entire circumference in a circumferential direction.

10. A balance weight according to any one of claims 5 to 9; A rotor rotatable about a central axis; an impeller portion connected to the rotor and rotatable about a central axis; Equipped with The rotating body is constituted by the rotor and the impeller portion.

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