JP2021164348A - Brushless DC motor - Google Patents

Abstract

To provide a technique of a brushless DC motor capable of holding a magnet even when the magnet is unbonded.SOLUTION: A brushless DC motor of a certain mode is a brushless DC motor provided to a ceiling fan, which includes: multiple magnets 42 that supply field magnetic flux; a rotor yoke 44 with multiple magnets 42 fixed; and a magnet holder 310 that includes a ring 301 facing multiple magnets 42 in the axial direction, and a first engaging portion 302 protruding from the ring portion 301 and engaged with the rotor yoke 44.SELECTED DRAWING: Figure 7

Description

The present disclosure relates to a brushless DC motor.

Brushless DC motors are known that include a rotor with a magnet. For example, Patent Document 1 describes a motor including a stator portion and a rotor portion. The rotor portion of this motor includes a shaft, a rotor holder, and a plurality of rotor magnets. The rotor holder has a lid portion and a cylindrical portion that hangs down from the radial outside of the lid portion. The plurality of magnets are arranged in an annular shape on the inner peripheral surface of the cylindrical portion of the rotor holder and fixed by an adhesive.

Japanese Unexamined Patent Publication No. 2010-098783

Since the ceiling fan is used for a long period of time once it is installed, the brushless DC motor mounted on the ceiling fan is also required to have a long life. However, when the magnet is fixed to the cylindrical portion of the rotor holder with an adhesive as in the motor described in Patent Document 1, the adhesive strength of the magnet varies widely, and the adhesive strength decreases due to factors such as aging deterioration. , The magnet may come off. When the magnet is disattached, the magnet falls off from the rotor holder and comes into contact with the stator to generate a contact noise, which in turn hinders rotation.

The present disclosure has been made to solve the above problems, and an object of the present invention is to provide a technique of a brushless DC motor capable of holding a magnet even if the magnet is detached.

In order to solve the above problems, the brushless DC motor according to an embodiment of the present invention is a brushless DC motor provided on a ceiling fan, in which a plurality of magnets for supplying field magnetic flux and a rotor yoke in which the plurality of magnets are fixed are fixed. A magnet holder having a ring portion that faces a plurality of magnets in the axial direction and a first engaging portion that protrudes from the ring portion and is engaged with the rotor yoke.

It should be noted that the expression of the present disclosure converted between methods, devices, systems, recording media, computer programs, etc. is also effective as an aspect of the present disclosure.

According to the present disclosure, it is possible to provide a technique of a brushless DC motor capable of holding a magnet even if the magnet is unbonded.

FIG. 1 is a perspective view showing a ceiling fan provided with a motor according to an embodiment. FIG. 2 is a cross-sectional view showing the peripheral structure of the motor of FIG. FIG. 3 is an exploded perspective view of the motor of FIG. FIG. 4 is a side view showing the stator of the motor of FIG. FIG. 5 is a bottom view showing the circuit board of the motor of FIG. FIG. 6 is a block diagram showing the configuration of the circuit board of the motor of FIG. FIG. 7 is a perspective view showing the inside of the rotor of the motor of FIG. FIG. 8 is an enlarged view showing a part of the first magnet holder of the motor of FIG. 1 in an enlarged manner. FIG. 9 is a perspective view of the first magnet holder of the motor of FIG. FIG. 10 is a plan view showing the first magnet holder and the magnet of the motor of FIG.

Hereinafter, embodiments for carrying out the present disclosure will be described with reference to the accompanying drawings. In the examples and modifications, the same or equivalent components and members are designated by the same reference numerals, and redundant description will be omitted as appropriate. In addition, the dimensions of the members in each drawing are shown enlarged or reduced as appropriate for easy understanding. In addition, some of the members that are not important for explaining the embodiment in each drawing are omitted and displayed.

In addition, terms including ordinal numbers such as 1st and 2nd are used to describe various components, but this term is used only for the purpose of distinguishing one component from other components, and this term is used. The components are not limited by.

The motor 10 according to the embodiment of the present disclosure is a brushless DC motor provided in the ceiling fan 1. First, the overall configuration of the ceiling fan 1 will be described. FIG. 1 is a perspective view showing a ceiling fan 1. The ceiling fan 1 is attached to the ceiling 4 and functions as a fan having a plurality of blades 2 that generate an air flow by rotating. The ceiling fan 1 includes a motor 10 that rotates a plurality of blades 2 and a housing 5 that extends downward from the ceiling 4 and surrounds the motor 10. The ceiling fan 1 is provided with a lighting unit 3 having a light emitting element such as an LED at the lower end thereof.

The housing 5 has a substantially conical first portion 5a whose diameter gradually decreases downward from the ceiling side, and a substantially conical second portion whose diameter gradually increases downward from the lower portion of the first portion 5a. Has 5b and. The connecting portion 5c of the first portion 5a and the second portion 5b is narrowed down more than the first portion 5a and the second portion 5b. The lower part of the second portion 5b exhibits a cylindrical shape having a constant diameter. The second portion 5b functions as an outer shell that houses the motor 10.

See FIGS. 2 to 4. FIG. 2 is a cross-sectional view showing the peripheral structure of the motor 10 of the ceiling fan 1. FIG. 3 is an exploded perspective view of the motor 10. FIG. 4 is a side view showing the stator 20. The motor 10 mainly includes a stator 20, a shaft 30, a rotor 40, a first bearing 32, a second bearing 34, a circuit board 48, a blade holder 70, and a rotation detection unit 400. Hereinafter, the direction along the central axis La of the shaft 30 is referred to as "axial direction", and the circumferential direction and radial direction of the circle centered on the central axis La are referred to as "circumferential direction" and "diameter direction", respectively. Further, hereinafter, for convenience, one side (upper side in the figure) in the axial direction is referred to as "upper" and "upper", and the other side (lower side in the figure) is referred to as "lower" and "lower". The notation in such a direction does not limit the posture in which the motor 10 is used, and the motor 10 can be used in any posture.

First, the operation of the motor 10 and the ceiling fan 1 will be described. In the ceiling fan 1, the stator 20, the shaft 30, the circuit board 48, and the rotation detection unit 400 form a stationary body, and the rotor 40, the blade holder 70, and the plurality of blades 2 form a rotating body. The circuit board 48 supplies a drive current to the stator 20 based on the detection signal of the rotation detection unit 400. The stator 20 generates a rotating magnetic field according to the driving current. The rotor 40 rotates around the central axis La according to the rotating magnetic field. The blade holder 70 rotates a plurality of blades 2 by rotating integrally with the rotor 40. The plurality of blades 2 generate a downward air flow by rotating. Hereinafter, each part will be described in detail.

The first bearing 32, the rotor 40 and the stator 20, the circuit board 48, and the second bearing 34 are arranged in this order from top to bottom and surround the shaft 30. The rotor 40 is arranged so as to face the stator 20 in the radial direction. The rotor 40 and the stator 20 have a larger diameter than the first bearing 32, and the circuit board 48 has a larger diameter than the rotor 40 and the stator 20. The shaft 30 is a pipe-shaped member having a hollow portion in the center for passing a wire for wiring. The hollow portion of the shaft 30 penetrates vertically, and a horizontal hole 30h for passing a wire is provided on the side surface of the shaft 30.

The stator 20 has a stator core 22 around which a coil 24 is wound. The coil 24 constitutes a three-phase armature coil. The shaft 30 is fixed to the central portion of the stator core 22. The rotor 40 has a magnet 42 that surrounds the stator core 22, and is fixed to the outer ring of the first bearing 32.

The stator core 22 has a plurality of (for example, 12) teeth portions 22t and a plurality of slots 22s provided between the plurality of teeth portions 22t. The side surface of each slot 22s leads to the opening 22k of the stator core 22. An insulating sheet 23 made of a resin film is inserted into each slot 22s. The insulating sheet 23 includes a slot insulator 23b that covers the inner side surface (the surface on the slot 22s side) of the teeth portion 22t, and a slot key 23c provided on the outer peripheral side of the slot 22s. The insulating sheet 23 of this example protrudes in the axial direction from the end surface of the tooth portion 22t. Insulating members 200 are provided on the upper surface and the lower surface of the stator core 22, respectively. The insulating member 200 functions as a core cover that covers a part of each tooth portion 22t. The insulating member 200 is a resin member formed by molding.

The coil 24 includes a plurality of (for example, 12) coil main body portions 24a wound around each tooth portion 22t. The plurality of coil main bodies 24a are connected in series for each phase. The terminal of the coil body 24a of each phase is connected to a motor drive circuit described later.

The rotor 40 has a rotor yoke 44. The rotor yoke 44 includes a hollow disk-shaped top plate portion 44a, a cylindrical magnet support portion 44b extending downward from the outer peripheral portion of the top plate portion 44a, and a donut extending radially outward from the lower portion of the magnet support portion 44b. It has a shaped extending portion 44c. The central portion of the top plate portion 44a is fixed to the outer ring of the first bearing 32. The magnet 42 is fixed to the inner peripheral surface of the magnet support portion 44b. The outer peripheral portion of the extending portion 44c is fixed to the blade holder 70 by the male screw S1.

The magnet 42 has a plurality of (for example, 10) magnetic poles that supply field magnetic flux to the stator core 22. The magnet 42 is divided into a plurality of segments. As shown in FIG. 4, the upper end and the lower end of the magnet 42 extend up and down by a predetermined dimension (for example, 5 mm) of the stator core 22.

As shown in FIG. 3, the rotor 40 has a magnet holder 300 that holds the magnet 42 in a predetermined position. The magnet holders 300 are arranged above and below the magnet 42 to limit the axial position of the magnet 42. The magnet holder 300 includes a first magnet holder 310 arranged below the magnet 42 and a second magnet holder 320 arranged above the magnet 42. The outer peripheral portion of the first magnet holder 310 is locked to the rotor yoke 44, which limits the downward movement of the magnet 42. The second magnet holder 320 limits the upward movement of the magnet 42. The first magnet holder 310 and the second magnet holder 320 are substantially ring-shaped resin members that can be elastically deformed.

As shown in FIG. 2, the first bearing 32 and the second bearing 34 are rolling bearings having a rolling element 33 such as a ball. The inner rings of the first bearing 32 and the second bearing 34 are fixed to the shaft 30 via the E washers 32c and 34c. The first bearing 32 and the second bearing 34 are arranged vertically separated from each other with the stator core 22 and the circuit board 48 interposed therebetween. The first bearing 32 is arranged above the stator core 22. The second bearing 34 is arranged below the circuit board 48 on the opposite side of the stator core 22 from the first bearing 32.

5 and 6 are also referred to. FIG. 5 is a bottom view showing the circuit board 48. FIG. 6 is a block diagram showing the configuration of the circuit board 48. The circuit board 48 includes a wiring board 50, a primary power supply circuit 51, a secondary power supply circuit 52, and a motor drive circuit 53. The primary side power supply circuit 51, the secondary side power supply circuit 52, and the motor drive circuit 53 are provided on the wiring board 50. The wiring board 50 is a printed circuit board.

The primary power supply circuit 51 rectifies the input AC voltage (for example, 220V to 240V) and supplies the first DC voltage V1 (for example, 310V to 340V). The secondary power supply circuit 52 supplies a 15V second DC voltage V2 and a 5V third DC voltage V3 by the DC-DC converters 52a and 52b based on the first DC voltage.

The motor drive circuit 53 includes a microprocessor 53a, a control unit 53b, and a switching unit 53c, and supplies a drive current to the coil 24. The first DC voltage V1 is mainly supplied to the switching unit 53c. The second DC voltage V2 is mainly supplied to the control unit 53b. The third DC voltage V3 is mainly supplied to the microprocessor 53a. The control unit 53b generates an FG signal based on the position signals Hs acquired from the Hall elements HE1, HE2, and HE3 of the rotation detection unit 400, and outputs the FG signal to the microprocessor 53a.

The microprocessor 53a generates a rotation control signal Cs for controlling the rotation of the motor 10 based on the FG signal output from the control unit 53b, and outputs the rotation control signal Cs to the control unit 53b. The control unit 53b generates a phase switching signal Qs for energizing phase switching based on the position signal Hs acquired from the Hall element of the rotation detection unit 400. The control unit 53b generates a PWM signal Ps based on the rotation control signal Cs and the phase switching signal Qs output from the microprocessor 53a and outputs the PWM signal Ps to the switching unit 53c.

The switching unit 53c includes a switching element (not shown) constituting the three-phase bridge. The switching unit 53c controls the continuity / non-passage of the switching element based on the PWM signal Ps output from the control unit 53b, and causes a drive current to flow through the coil 24. The control unit 53b and the switching unit 53c form a three-phase inverter. The switching unit 53c of this embodiment is realized by a one-chip motor drive IC.

As shown in FIG. 5, the circuit board 48 of this embodiment communicates with the sub-wiring board 49, the lighting drive circuit 55 for driving the lighting unit 3, and a remote controller (not shown) for remotely controlling the ceiling fan 1. It further includes a communication circuit 56. The illumination drive circuit 55 is provided on the sub wiring board 49, and the communication circuit 56 is provided on the wiring board 50. The sub wiring board 49 is a printed wiring board.

As shown in FIG. 4, the circuit board 48 has a ring shape surrounding the shaft 30 and is provided between the stator core 22 and the second bearing 34 in the axial direction. The circuit board 48 is supported by the stator core 22 by fixing the wiring board 50 to the stator core 22 via the substrate holding portion 100. The sub-wiring board 49 is fixed to the lower surface of the wiring board 50 via the board holder 60. As shown in FIG. 5, the wiring board 50 is a ring-shaped circular member having a central hole 50h, and the sub-wiring board 49 is a partial member in the ring shape.

As shown in FIG. 5, a wiring connection component 58 such as a connector for connecting wiring is mounted on the lower surface 50j of the wiring board 50 on the side opposite to the stator core 22. The wiring connection component 58 in this example is a male connector. As a result, at the time of assembling the motor 10, the female connector to which the lead wire is connected to the wiring connection component 58 can be easily attached / detached while the circuit board 48 is fixed to the stator core 22 via the substrate holding portion 100. Assembly workability and maintainability are improved. Further, since the wiring board 50 can be brought close to the stator core 22, it is advantageous for thinning.

As shown in FIG. 4, the electronic component 51p constituting the primary power supply circuit 51 is mounted on the lower surface 50j of the wiring board 50 opposite to the stator core 22. As a result, the heat generated in the electronic component 51p is blocked by the wiring board 50, so that heat conduction to the stator 20 and the rotor 40 is reduced, the temperature rise of the coil 24 is suppressed, and quality deterioration can be prevented.

As shown in FIG. 3, a heat radiating section 46 that dissipates heat from the motor drive circuit 53 is provided between the board holding section 100 and the wiring board 50. The heat radiating unit 46 promotes heat radiating from the motor drive IC (switching unit 53c) of the motor drive circuit 53 and suppresses the temperature rise.

As shown in FIG. 4, the rotation detection unit 400 includes Hall elements HE1, HE2, HE3 for detecting the magnetic flux of the magnet 42, and an HE holder 410. The Hall elements HE1, HE2, and HE3 are arranged at positions deviated by 120 degrees in the electrical angle in the circumferential direction. The Hall element HE2 is arranged at a position of a predetermined opening 22k (hereinafter, referred to as an opening 22k (H)) in the circumferential direction. The input / output terminals of the Hall elements HE1, HE2, and HE3 are connected to the circuit board 48. The output signals of the Hall elements HE1, HE2, and HE3 are input to the control unit 53b. The HE holder 410 is a member that supports the Hall elements HE1, HE2, and HE3, is held by the substrate holding portion 100, and is sandwiched and fixed between the wiring board 50 and the stator core 22. The HE holder 410 has a convex portion 420 that projects upward and engages the opening 22k (H).

As shown in FIG. 2, the blade holder 70 rotates integrally with the rotor 40, and transmits the rotation of the rotor 40 to a plurality of (for example, five) blades 2. The blade holder 70 is a hollow circular member, and extends inward in the radial direction from the holder cylindrical portion 70a, the trumpet-shaped portion 70b extending downward from the lower portion of the holder cylindrical portion 70a, and the lower portion of the holder cylindrical portion 70a. It has a hollow disk-shaped holder disk portion 70c extending and a holder flange portion 70d extending radially outward from the lower portion of the trumpet-shaped portion 70b.

As shown in FIG. 2, the upper portion of the holder cylindrical portion 70a is fixed to the extending portion 44c of the rotor yoke 44. The holder cylindrical portion 70a surrounds the circuit board 48 with a gap. The outer ring of the second bearing 34 is fixed to the central portion of the holder disk portion 70c. A plurality of blades 2 are fixed to the holder flange portion 70d. The plurality of blades 2 are arranged at predetermined intervals in the circumferential direction, and extend outward in the radial direction from the holder flange portion 70d. The lower portion of the trumpet-shaped portion 70b surrounds the upper portion of the illumination portion 3 with a gap. The upper portion of the illumination unit 3 is fixed to the lower portion of the shaft 30.

The first magnet holder 310 will be described with reference to FIGS. 7 to 10. FIG. 7 is a perspective view showing the inside of the rotor 40. FIG. 8 is an enlarged view showing a part of the first magnet holder 310 in an enlarged manner. FIG. 9 is a perspective view of the first magnet holder 310. FIG. 10 is a plan view showing the first magnet holder 310 and the magnet 42.

The first magnet holder 310 has a ring portion 301, a first engaging portion 302, an arm portion 303, a stopper portion 304, and a holding portion 305. The ring portion 301, the first engaging portion 302, the arm portion 303, the stopper portion 304, and the holding portion 305 are integrally formed by resin molding. The ring portion 301 is a ring-shaped portion that faces the plurality of magnets 42 in the axial direction. In this example, the ring portion 301 comes into contact with the lower end surfaces of the plurality of magnets 42.

The first engaging portion 302 is a portion that protrudes from the ring portion 301 and is engaged with the rotor yoke 44. In the present embodiment, five first engaging portions 302 are provided at intervals of 72 ° in the circumferential direction. The first engaging portion 302 has a rectangular shape whose long side extends in the circumferential direction in a plan view. The first engaging portion 302 engages with the second engaging portion 45 provided on the extending portion 44c of the rotor yoke 44.

In the present embodiment, the extending portion 44c is provided with five second engaging portions 45 at intervals of 72 ° in the circumferential direction. The shape of the second engaging portion 45 is not limited, but the second engaging portion 45 of the present embodiment has a protrusion 45a cut up from the extending portion 44c. The protrusion 45a has a first portion 45p extending in a direction away from the extending portion 44c (axial direction), and a second portion 45s bent at the extending end of the first portion 45p and extending inward in the radial direction. .. The first engaging portion 302 enters between the extending portion 44c and the second portion 45s.

The circumferential width of the first engaging portion 302 is larger than the circumferential width of the protrusion 45a. The first engaging portion 302 is provided with a recess 302b that accommodates at least a part of the second portion 45s. By fitting the second portion 45s into the recess 302b, the first magnet holder 310 is positioned in the circumferential direction with respect to the rotor yoke 44 (extending portion 44c).

A pair of arm portions 303 are provided for each first engaging portion 302. The pair of arm portions 303 extend from positions separated in the circumferential direction of the ring portion 301 so as to approach each other and are connected to the first engaging portion 302. The arm portion 303 of this example is bent at the extending ends of the first arm portion 303p extending radially outward from the ring portion 301 and the extending end of the first arm portion 303p, and extends in the circumferential direction to the first engaging portion 302. It has a second arm portion 303s to be connected. The pair of arm portions 303 have a spring property that allows the first engaging portion 302 to move in the radial direction within a predetermined range.

One stopper 304 is provided for each first engaging portion 302. The stopper portion 304 projects from the outer circumference of the ring portion 301 toward the first engaging portion 302 and faces the first engaging portion 302 in the radial direction through a gap. The stopper portion 304 restricts the movement of the first engaging portion 302 inward in the radial direction. The shape of the stopper portion 304 is not limited, but the stopper portion 304 of the present embodiment has a substantially trapezoidal shape in which the upper base (short side) faces the first engaging portion 302 in a plan view. The circumferential center of the stopper portion 304 is provided at a position corresponding to the circumferential center of the first engaging portion 302. By having the stopper portion 304, the radial wall thickness of the ring portion 301 is increased at that portion, and the rigidity of the ring portion 301 is increased.

The holding portion 305 protrudes from the ring portion 301 at a position corresponding to the circumferential boundary 42b of the two adjacent magnets 42 of the plurality of magnets 42, and covers a part of the inner peripheral surfaces of the two magnets 42. That is, the holding portion 305 projects in the vertical direction from the ring portion 301 along the inner peripheral surface 42j of the magnet 42. The holding portion 305 has a surface parallel to the inner peripheral surface 42j of the magnet 42. The circumferential boundary 42b is a line that bisects the distance between the circumferential ends of two adjacent magnets 42 in the circumferential direction. In the present embodiment, 10 holding portions 305 are provided at intervals of 36 ° in the circumferential direction. The shape of the holding portion 305 is not limited, but the holding portion 305 of the present embodiment has a substantially pentagonal shape in which an isosceles triangle is superimposed on a rectangle in a plan view. The apex of the holding portion 305 faces the circumferential boundary 42b in the radial direction.

In the circumferential direction, the centers of the recess 302b, the first engaging portion 302, and the stopper portion 304 are located at the same positions as the center of the holding portion 305.

The second magnet holder 320 will be described. As described above, the second magnet holder 320 is arranged above the magnet 42. The second magnet holder 320 has a ring portion 301, a stopper portion 304, and a holding portion 305. The ring portion 301, the stopper portion 304, and the holding portion 305 of the second magnet holder 320 have the same shape as the ring portion 301, the stopper portion 304, and the holding portion 305 of the first magnet holder 310, and overlapping description is omitted.

The ring portion 301 of the second magnet holder 320 comes into contact with the top plate portion 44a of the rotor yoke 44. The holding portion 305 of the second magnet holder 320 projects downward from the ring portion 301 and holds the upper side of the magnet 42. That is, the magnet 42 is held from below and above by the holding portions 305 of the first magnet holder 310 and the second magnet holder 320. With this configuration, when the adhesion of the magnet 42 is peeled off, it is possible to prevent the magnet 42 from coming off and coming into contact with the stator core 22 to generate a sliding noise.

The second magnet holder 320 may have the first engaging portion 302 and the arm portion 303, but in this example, the second magnet holder 320 does not have the first engaging portion 302 and the arm portion 303. The second magnet holder 320 may be molded with a mold different from that of the first magnet holder 310, but in this example, the second magnet holder 320 is molded with the same mold, and the first engaging portion 302 and the arm portion 303 are cut off. .. In this case, the mold cost can be suppressed, which is advantageous in terms of man-hours for manufacturing and management. Further, the first and second magnet holders 310 and 320 may be made separately by nesting the portions corresponding to the first engaging portion 302 and the arm portion 303 of the same mold and exchanging the nests. In this case as well, the mold cost can be suppressed.

An example of a method for manufacturing the rotor 40 will be described.
(1) First, the second magnet holder 320 is attached to the rotor yoke 44. Adhesives may or may not be applied to these.
(2) Ten magnets 42 are adhered to the magnet support portion 44b of the rotor yoke 44. In this step, each magnet 42 is arranged so as to fit between two adjacent holding portions 305 of the second magnet holder 320. At this time, the holding portion 305 fits in the gap between the two adjacent magnets 42. The adhesive is applied to the magnet support 44b or each magnet 42. The adhesive may be anaerobically cured or heat cured.

(3) After the adhesive is cured, the first magnet holder 310 is attached. At this time, the first magnet holder 310 is positioned so that the holding portion 305 fits in the gap between the two adjacent magnets 42.
(4) The first engaging portion 302 of the first magnet holder 310 is engaged with the second engaging portion 45 of the rotor yoke 44. At this time, the first engaging portion 302 is pushed inward in the radial direction to elastically deform the pair of arm portions 303, the second portion 45s is housed in the recess 302b, and the pushing is released in that state. In the engaged state, the elastic force of the pair of arm portions 303 applies a radial outward urging force to the first engaging portion 302. As a result, the first magnet holder 310 is mounted on the rotor yoke 44 with almost no rattling.
(5) The magnet 42 is magnetized after the adhesive has hardened or after the first magnet holder 310 has been attached.
This process is merely an example, and some processes may be added, deleted, changed, or the order of the processes may be changed.

According to this embodiment, since the plurality of magnets 42 are supported in the axial direction by the magnet holder 300 having the first engaging portion 302 engaged with the rotor yoke 44, even if the adhesion is removed due to aged deterioration, the magnets Can be held without falling off. Therefore, it is advantageous for extending the life of the ceiling fan. In addition, the bonding area can be reduced, and the vertical length of the magnet can be shortened accordingly, so that the brushless DC motor can be easily made thinner. As a result, the vertical length of the ceiling fan can be shortened, the blades can be provided at a high position, and the air flow can be dispersed over a wide range. Since the downward air flow can be spread over a wide area, it is possible to reduce the unevenness of the air volume near the floor and improve the comfort. In addition, interference with humans can be avoided. Further, by making the motor 10 thinner, the connection portion 5c of the housing 5 can be made thinner, so that the air flow guided to the blades 2 becomes smooth at this portion, which is advantageous in reducing power consumption. Further, since the ceiling fan is required to have low noise, the contact noise with the stator core 22 due to the magnet 42 falling off can be prevented, which is advantageous for reducing the noise of the ceiling fan.

Further, according to the present embodiment, since the second engaging portion 45 uses the protrusion 45a cut up from the extending portion 44c, it can be easily formed in the pressing process of the rotor yoke 44, and the mold cost can be suppressed. Further, since the holding portion 305 is provided, the magnet 42 can be held in the radial direction. Since the holding portion 305 regulates the relative movement of the first magnet holder 310 and the magnet 42 in the circumferential direction, the magnet 42 can be positioned. Further, since it has a pair of arm portions 303 connected to the first engaging portion 302, the first engaging portion 302 is easily deformed at the time of insertion and is easily inserted. Further, since the stopper portion 304 is provided, excessive deformation of the arm portion 303 can be suppressed to prevent breakage, and further damage to the ring portion 301 can be reduced.

The outline of one aspect of the present disclosure is as follows. The brushless DC motor (10) of a certain aspect of the present disclosure is a brushless DC motor provided in the ceiling fan (1), and includes a plurality of magnets (42) for supplying field magnetic flux and a plurality of magnets (42). A fixed rotor yoke (44), a ring portion (301) that is axially opposed to a plurality of magnets (42), and a first engagement that protrudes from the ring portion (301) and is engaged with the rotor yoke (44). A magnet holder (310) having a portion (302) and a portion (302).

The rotor yoke (44) has a cylindrical magnet support portion (44b) to which a plurality of magnets (42) are fixed, and a first engaging portion (302) extending radially outward from the lower portion of the magnet support portion (44b). ) May have an extension portion (44c) provided with a second engaging portion (45).

The second engaging portion (45) may have a protrusion (45a) cut up from the extending portion (44c).

The magnet holder (310) protrudes from the ring portion (301) at a position corresponding to the circumferential boundary between two adjacent magnets (42) of the plurality of magnets (42), and the inner peripheral surfaces of the two magnets (42). It may have a holding portion (305) that covers a part.

The holding portion (305) may regulate the relative movement of the magnet holder (310) and the magnet (42) in the circumferential direction.

The magnet holder (310) has a pair of arm portions (303) extending from positions separated in the circumferential direction of the ring portion (301) so as to approach each other and connected to the first engaging portion (302). May be good.

The magnet holder (310) may have a stopper portion (304) that protrudes from the outer circumference of the ring portion (301) and restricts the movement of the first engaging portion (302) inward in the radial direction.

The present disclosure has been described above based on the examples. This embodiment is an example, and it will be understood by those skilled in the art that various modifications are possible for each of these components or combinations of each processing process, and that such modifications are also within the scope of the present disclosure. ..

10 Brushless DC motor, 42 magnet, 42b circumferential boundary, 44 rotor yoke, 44b magnet support, 44c extension, 45 second engagement, 45a protrusion, 301 ring, 302 first engagement, 303 arm , 304 Stopper, 305 Holding, 310 1st Magnet Holder.

Claims (7)

A brushless DC motor installed in a ceiling fan
Multiple magnets that supply field magnetic flux,
The rotor yoke to which the plurality of magnets are fixed and
A magnet holder having a ring portion that faces the plurality of magnets in the axial direction and a first engaging portion that protrudes from the ring portion and is engaged with the rotor yoke.
A brushless DC motor characterized by being equipped with. The rotor yoke has a tubular magnet support portion to which the plurality of magnets are fixed, and a second engaging portion that extends radially outward from the lower portion of the magnet supporting portion and engages with the first engaging portion. The brushless DC motor according to claim 1, further comprising an extension portion provided. The brushless DC motor according to claim 2, wherein the second engaging portion has a protrusion cut up from the extending portion. The magnet holder is characterized by having a holding portion that protrudes from the ring portion at a position corresponding to the circumferential boundary of two adjacent magnets of the plurality of magnets and covers a part of the inner peripheral surfaces of the two magnets. The brushless DC motor according to any one of claims 1 to 3. The brushless DC motor according to claim 4, wherein the holding portion regulates relative movement of the magnet holder and the magnet in the circumferential direction. Claims 1 to 5, wherein the magnet holder has a pair of arm portions extending from positions apart from each other in the circumferential direction of the ring portion so as to approach each other and connected to the first engaging portion. The brushless DC motor according to any one item. The method according to any one of claims 1 to 6, wherein the magnet holder has a stopper portion that protrudes from the outer circumference of the ring portion and restricts the movement of the first engaging portion in the radial direction. Brushless DC motor.

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