JP7453829B2 - fan motor - Google Patents

Description

The present invention relates to a fan motor.

A fan motor is a device that cools the inside of a computer, office automation equipment, etc. by rotating a fan (blade) to discharge heat generated inside a personal computer, OA equipment, etc., to the outside using wind power.

A fan motor in which the internal stator and circuit board are sealed (molded) with synthetic resin has been proposed so that it can be used in places exposed to water or oil or in places with a lot of dust (see, for example, Patent Document 1). .

In general, in this type of fan motor, the stator is fixed around a cylindrical member called a bearing holder or bearing support tube (hereinafter referred to as the "bearing holder"), and the bearing is connected to the circuit board with the wiring connected to it. A mold is brought into close contact with both ends of the holder, and sealing is performed to enclose the stator and circuit board so as to prevent synthetic resin from flowing into the inside of the bearing holder. After sealing is performed, a bearing that supports the rotating shaft is installed inside the bearing holder.

Japanese Patent Application Publication No. 2001-128408

However, when sealing, if the two ends of the bearing holder and the mold are not completely sealed and a slight gap is created, the synthetic resin will flow into the inside of the bearing holder. This will cause burrs. This burr poses no particular problem as long as it remains on the end face of the bearing holder, but if the burr reaches the inner circumferential surface of the bearing holder, the bearing cannot be mounted on the inner circumferential surface of the bearing holder, and the excess burr It will be necessary to remove the .

The present invention has been made in view of the above, and an object of the present invention is to provide a fan motor that does not generate burrs at both ends of a bearing holder due to sealing and does not increase the number of work steps.

In order to solve the above problems and achieve the objects, a fan motor according to one aspect of the present invention includes a housing, a base portion, a bearing holder, a stator, a circuit board, and a synthetic resin. The base portion is fixed to the housing. The bearing holder has a cylindrical shape and is fixed to the base portion. The stator is attached to an outer periphery of the bearing holder. The circuit board is electrically connected to the coil of the stator, and is mounted on the opposite side of the stator across the base portion in the axial direction . The synthetic resin seals the bearing holder, the stator, and the circuit board except for both end surfaces of the bearing holder. Both end surfaces of the metal bearing holder have one or more annular recesses.

The fan motor according to one aspect of the present invention does not generate burrs at both ends of the bearing holder due to sealing, and does not increase the number of work steps.

FIG. 1 is an external perspective view showing a configuration example of a fan motor according to an embodiment. FIG. 2 is a plan view of the fan motor of FIG. 1. FIG. 3 is a sectional view taken along line AA of the fan motor shown in FIG. FIG. 4 is a plan view showing a state in which the stator is attached to a bearing holder insert-molded into a base portion integrally molded with the housing. FIG. 5 is a bottom view of the fan motor of FIG. 4. FIG. 6 is an enlarged view of the vicinity of the through hole and ribs in FIG. 5. FIG. 7 is a BO-B sectional view of the fan motor of FIG. 5. FIG. FIG. 8 is a bottom view of the state shown in FIG. 5 with the circuit board attached. FIG. 9 is a BO-B cross-sectional view of the fan motor in FIG. 8. FIG. 10 is a cross-sectional view showing an enlarged range V1 in FIG. 9. As shown in FIG. FIG. 11 is a cross-sectional view showing a state in which the base portion, bearing holder, stator, and circuit board are sealed by a mold. FIG. 12 is a diagram (bottom view) of one end of the bearing holder viewed from the axial direction. FIG. 13 is a YY cross-sectional view of FIG. 12. FIG. 14 is a diagram (plan view) of the other end of the bearing holder viewed from the axial direction. FIG. 15 is a YY cross-sectional view of FIG. 14. FIG. 16 is a cross-sectional view through the connector housing of the fan motor. FIG. 17 is a sectional view showing a configuration example of Comparative Example #1. FIG. 18 is a sectional view showing a configuration example of Comparative Example #2. FIG. 19 is a sectional view showing a configuration example of Comparative Example #3.

Hereinafter, a fan motor according to an embodiment will be described with reference to the drawings. Note that the present invention is not limited to this embodiment. Furthermore, the dimensional relationship of each element, the ratio of each element, etc. in the drawings may differ from reality. Drawings may also include portions that differ in dimensional relationships and ratios. Moreover, the content described in one embodiment or modification example is, in principle, similarly applied to other embodiments or modification examples.

FIG. 1 is an external perspective view showing a configuration example of a fan motor 1 according to an embodiment. For convenience, the axial direction (rotational axis direction) of the fan motor 1 is defined as the Z-axis direction, and the two orthogonal sides of the housing 11 in the longitudinal direction are defined as the X-axis direction and the Y-axis direction, respectively. FIG. 2 is a plan view of the fan motor 1 of FIG. 1. FIG. 3 is a sectional view taken along line AA of the fan motor 1 shown in FIG.

FIG. 4 is a plan view showing a state in which the stator 21 is attached to the bearing holder 17 that is insert-molded on the base portion 12 that is integrally molded with the housing 11. As shown in FIG. FIG. 5 is a bottom view of the fan motor 1 of FIG. 4. FIG. 6 is an enlarged view of the vicinity of the through hole 12d and rib 12e in FIG. FIG. 7 is a BO-B cross-sectional view of the fan motor 1 in FIG.

FIG. 8 is a bottom view of the state shown in FIG. 5 with the circuit board 26 attached. FIG. 9 is a BO-B cross-sectional view of the fan motor 1 in FIG. FIG. 10 is a cross-sectional view showing an enlarged range V1 in FIG. 9. As shown in FIG.

FIG. 11 is a cross-sectional view showing a state in which the base portion 12, bearing holder 17, stator 21, and circuit board 26 are sealed by molds 91 and 92. FIG. 12 is a diagram (bottom view) of one end (the mold 92 side) of the bearing holder 17 viewed from the axial direction. FIG. 13 is a cross-sectional view taken along the YY line in FIG. 12. FIG. 14 is a diagram (plan view) of the other (mold 91 side) end of the bearing holder 17 viewed from the axial direction. FIG. 15 is a YY cross-sectional view of FIG. 14. FIG. 16 is a sectional view through the connector housing 15 of the fan motor 1.

The structure of the fan motor 1 will be explained below along with the manufacturing process.

(Production of housing)
Mainly in FIGS. 1 to 10, a housing 11 and a base part 12 are formed by injection molding of thermoplastic resin with a hollow cylindrical bearing holder 17 made of a non-magnetic metal material such as brass inserted. The spokes 13 (including the wide portion 14) and the connector housing 15 are integrally formed.

The housing 11 is provided with a frame portion 11a constituting an outer frame, a hollow cylindrical wind tunnel portion 11b, and substantially square flanges 11c on both axial end faces of the wind tunnel portion 11b. The four corners of the flange 11c are provided with through holes 11d into which mounting screws and the like are inserted. A base portion 12 and a plurality of spokes 13 (including a wide portion 14) are provided at one end in the axial direction of the wind tunnel portion 11b, and a connector housing 15 is integrally formed on a part of the outer periphery of the housing 11. It is formed. The connector housing 15 is provided with a frame portion 15a continuous to the housing 11, and a plurality of connector pins 16 are inserted into the frame portion 15a and are disposed integrally with the connector housing 15.

The base portion 12 has an annular annular portion 12a, and a bearing holder 17 is disposed at the center of the annular portion 12a. A cylindrical outer circumferential wall 12b is formed at the outer circumferential edge of the annular portion 12a, and one end of the outer circumferential wall 12b in the axial direction is open. Furthermore, cutouts 12c are formed at a plurality of locations on the outer peripheral wall 12b to engage with convex portions 26b (FIG. 8) formed on the outer peripheral edge of the circuit board 26.

The spokes 13 (including the wide portion 14) are arranged along the circumferential direction on the outer circumferential surface of the outer circumferential wall 12b, and connect the outer circumferential surface of the outer circumferential wall 12b and the inner circumferential surface of the frame portion 11a of the housing 11. There is. Further, one of the spokes 13 is made wider than the other spokes 13 as a wide part 14 and extends toward the connector housing 15, and at this point, an extended part 26d of the circuit board 26 is provided. is placed.

When the base part 12 is molded, a through hole 12d is formed in the base part 12 through which a plurality of terminal pins 24 disposed on the insulator 23 of the stator 21 are inserted, and a through hole 12d is formed in the base part 12 on the side where the circuit board 26 is arranged. A rib 12e surrounding the through hole 12d is integrally formed (FIGS. 5 and 6). This rib 12e is formed to surround the through hole 12d and the bearing holder 17. Further, the through hole 12d formed in the base portion 12 is formed in a conical shape whose diameter decreases toward the side where the circuit board 26 is disposed. The functions of the rib 12e and the through hole 12d will be described later.

(Production of stator, installation of stator, installation of circuit board)
Mainly in FIGS. 1 to 10, a stator core 22 constituting a stator 21 is constructed by laminating a plurality of thin plate-shaped core pieces in the axial direction. The stator core 22 includes an annular core back 22a and a plurality of teeth 22b extending radially outward from the core back 22a. The core piece is manufactured from a soft magnetic electromagnetic steel plate or the like by press working or the like.

Insulators 23 made of an insulating synthetic resin material are attached to both sides of the stator core 22 in the axial direction, and a coil 25 is wound around each tooth 22b via the insulators 23. The end of the coil 25 is connected to a terminal pin 24 disposed on one side of the insulator 23 in the axial direction, and is soldered (joined) to produce the stator 21.

The opening of the core back 22a of the stator core 22 constituting the stator 21 is fitted onto the outer peripheral surface of the bearing holder 17. At this time, the terminal pins 24 are inserted into the through holes 12d formed in the annular portion 12a of the base portion 12 (FIGS. 4 to 7).

Thereafter, the circuit board 26 on which electronic components and the like are mounted is mounted through the opening in the outer peripheral wall 12b of the base portion 12 (FIGS. 8 to 10). The circuit board 26 has a disk portion 26a and an extending portion 26d extending radially outward from a part of the outer periphery of the disk portion 26a. A plurality of convex portions 26b protruding outward are formed. The convex portion 26b is positioned by engaging with a notch 12c (FIG. 5) formed in the outer peripheral wall of the base portion 12.

When the circuit board 26 is mounted, the tip of each terminal pin 24 is inserted through the through hole 12d formed in the base part 12 from the opening in the outer circumferential wall 12b of the base part 12, and is inserted into the land of the wiring pattern of the circuit board 26. It is inserted into a through hole 26c formed in the section. Similarly, the tip of each connector pin 16 is inserted into a through hole 26e (FIG. 16) formed in a land portion of the wiring pattern of the circuit board 26. Then, the tips of the terminal pins 24 protruding from the land portions of the wiring pattern of the circuit board 26 and the tips of the connector pins 16 are soldered, respectively.

On the other hand, the through holes 12d and ribs 12e, which are integrally formed during the molding of the base portion 12, serve to prevent flux and solder balls from scattering. That is, when the terminal pin 24 and the wiring pattern of the circuit board 26 are electrically connected by soldering, the flux and solder balls may be scattered due to the flux boiling due to the heat during soldering. Even if the through hole 12d is surrounded by the rib 12e, the flux and solder balls accumulate inside the rib 12e and are prevented from scattering around.

Further, the rib 12e is continuous with another rib 12f (FIG. 6) on the base portion 12 surrounding the end portion of the bearing holder 17. This allows stable contact between the circuit board 26 and the ribs 12e, and more effectively prevents scattering of flux and solder balls during soldering.

The through hole 12d formed in the base portion 12 is formed in a conical shape whose diameter decreases toward the side where the circuit board 26 is disposed. Therefore, when the terminal pin 24 is soldered, even if the solder that flows through the through hole 26c of the circuit board 26 and forms the back fillet flows into the through hole 12d of the base portion 12, the solder will not flow through the rib 12e. Furthermore, since the through hole 12d is formed in a conical shape, it functions as a taper seal and is prevented from flowing out from the through hole 12d.

(Sealing with synthetic resin)
Mainly in FIGS. 11 to 16, the stator 21 to which the circuit board 26 is connected is set between molds 91 and 92, and transfer molding is performed using, for example, epoxy resin as the synthetic resin 51. This epoxy resin seals the entire outer peripheral surface of the stator core 22, the coil 25, and the circuit board 26 on which electronic components are mounted.

A gate port (resin injection gate) 15b for the epoxy resin injected into the molds 91 and 92 is arranged at the connector (FIGS. 5 and 16). The epoxy resin injected into the molds 91 and 92 from the gate port 15b by a predetermined injection pressure collides with the inside of the housing 11, and then separates and spreads in all directions. Of the epoxy resin divided into four directions, the epoxy resin flowing in the direction of the circuit board 26 presses the surface of the circuit board 26 on the gate opening 15b side (for convenience, referred to as the gate surface of the circuit board 26). tends to deform under the injection pressure of the resin.

Since the connector pins 16 are soldered to the wiring pattern of the circuit board 26, stress is concentrated at these soldered points. 15c is in contact with the surface of the circuit board 26 opposite to the surface on the gate opening 15b side (for convenience, this is referred to as the back surface of the circuit board 26). Therefore, the rib 15c that contacts the back surface of the circuit board 26 prevents the circuit board 26 from deforming under the injection pressure of the epoxy resin. Note that since the ribs 15c are provided in two rows in the arrangement direction of the connector pins 16 with the connector pins 16 in between, deformation of the circuit board 26 (extension portion 26d) at the base of the connector pins 16 is more effectively prevented. can do.

Since the vicinity of the gate opening 15b is most affected by the injection pressure of the epoxy resin, a rib 15c is formed inside the connector housing 15 and the rib 15c is brought into contact with the back surface of the circuit board 26. It also prevents deformation. For example, a rib 12g that contacts the back surface of the circuit board 26 is also formed on the back surface of the disk portion 26a to prevent the circuit board 26 from being deformed by the injection pressure of the epoxy resin.

On the other hand, annular recesses (grooves) 17a and 17b are formed on both axial end surfaces of the bearing holder 17 that come into contact with the molds 91 and 92 (FIGS. 12 to 15). In this embodiment, a concentric double-row (two-row) annular recess 17a is formed on one end surface of the bearing holder 17 in the axial direction (on the mold 92 side) (FIGS. 12 and 13). A row of annular recesses 17b is formed on the other end surface of the bearing holder 17 in the axial direction (on the mold 91 side) (FIGS. 14 and 15). Note that the illustrated annular recesses 17a and 17b have an acute-angled cross section on the side axially far from the end surface of the bearing holder 17, but the cross section on the side far from the end surface of the bearing holder 17 in the axial direction has a substantially circular shape. It may be arc-shaped.

When the molds 91 and 92 are clamped, the axial height of the stator 21 is manufactured to be within a predetermined range, but due to variations in the dimensions, the axial end face of the bearing holder 17 and the mold may 91, 92, the epoxy resin injected into the cavities of the molds 91, 92 may cause a slight gap between the axial end surface of the bearing holder 17 and the molds 91, 92. invade the gap. However, the epoxy resin that has entered the small gap enters the annular recesses 17a and 17b formed on the end face of the bearing holder 17 and is filled in the annular recesses 17a and 17b, so that the inner peripheral surface of the bearing holder 17 It doesn't reach that point.

In this way, the epoxy resin that has entered the small gap created between the axial end surface of the bearing holder 17 and the molds 91 and 92 enters the annular recesses 17a and 17b formed on the end surface of the bearing holder 17. As a result of being filled with resin, the resin burr does not reach the inner circumferential surface of the bearing holder 17, so that the bearing 31 can be easily mounted on the bearing holder 17 thereafter. The inner circumferential surfaces 17c and 17d on both end surfaces of the bearing holder 17 have a tapered shape whose diameter becomes smaller as it goes inside from the end surface side, so that it can easily enter the inner surface of the bearing holder 17 when the bearing 31 is installed. is easy.

(Production and installation of rotor)
Mainly in FIGS. 1 to 3, a protrusion 41a is formed in the center of a cup-shaped rotor yoke 41 made of a soft magnetic material by burring, and the rotating shaft 32 is press-fitted into the protrusion 41a. Then, the rotor yoke 41 to which the rotating shaft 32 is coupled is inserted, and a cup-shaped hub 43 and a plurality of blades 44 on the outer peripheral surface of the hub 43 are integrally molded on the outer periphery of the rotor yoke 41 by injection molding of thermoplastic resin. It is formed by Further, an annular magnet 42 is fixed to the inner peripheral surface of the rotor yoke 41.

On the other hand, two bearings 31 are fitted into the bearing holder 17 from both ends in the axial direction of the bearing holder 17 with a preload spring 35 interposed therebetween, and the rotating shaft 32 of the rotor is rotatably supported by the bearings 31. A grease holding plate 33 is attached to the rotating shaft 32, the grease holding plate 33 is filled with sealing grease 34, and a retaining ring 36 is attached to the end of the rotating shaft 32 opposite to the rotor yoke 41. The sealing grease 34 makes the bearing 31 waterproof.

<Comparative example>
FIG. 17 is a cross-sectional view showing a configuration example of Comparative Example #1, and is a cross-sectional view (half omitted) passing through the rotating shaft of the waterproof brushless fan motor disclosed in Japanese Patent Application Laid-Open No. 2001-128408. In FIG. 17, a housing part 18' surrounding the outer periphery of a plurality of blades 12' of a rotor 6' is provided, and a rotating shaft 13' of the rotor 6' is provided with a bearing 15' housed in a bearing supporting cylindrical part 17'. ', 16' are rotatably supported. Then, the stator 1', the circuit board 4' including electronic components, and the lead wires 21' are housed in the stator side case 14', and are molded using epoxy resin to form a molded part 24'. The magnetic pole surface 2b' of the stator magnetic pole is also covered with a molded portion 24'.

The control circuit and winding 3' on the circuit board 4' are connected to terminal pins 5' that are passed through through holes 4a' of the circuit board 4' and soldered to electrodes on the circuit board 4'. The lead wires are wrapped around and electrically connected. Therefore, when the terminal pin 5' and the circuit board 4' are electrically connected by soldering, there is a risk that the flux and solder balls will scatter due to the flux boiling due to the heat during soldering. be.

In addition, the end face of the bearing supporting cylindrical part 17' is in close contact with the inner surface of the mold, but if a slight gap occurs between the end face of the bearing supporting cylindrical part 17' and the inner surface of the mold. A portion of the molten resin enters this small gap, causing resin burrs. There is no particular problem with this resin burr as long as it remains on the end surface of the bearing support cylinder 17'. However, if the resin burr reaches the inner peripheral surface of the bearing support cylinder 17', the bearing support cylinder Bearings 15' and 16' cannot be mounted on the inner circumferential surface of bearing 17', which requires work to remove excess resin burrs.

Iron core 2', salient pole part 2a', winding 3', rotor side case 7', cup member 8', cylindrical part 8a', bottom wall part 8b', through hole 8c', blade attachment hub 9' , the cylindrical part 9a', the bottom wall part 9b', the rotor magnetic pole 10', the bush 11', the board storage part 19', the web 20', the lead wire storage groove 22', and the communication path 23' will not be described. do.

FIG. 18 is a cross-sectional view showing a configuration example of Comparative Example #2, and is a cross-sectional view passing through the rotating shaft of the rotating electric machine disclosed in JP-A-2018-007303. In FIG. 18, the motor as a rotating electric machine includes a rear frame end 215' in which a frame through hole is formed, a winding extension part 213b', and a control board 218' soldered to the winding extension part 213b'. It is equipped with Furthermore, a grommet 221' is provided on the side of the rear frame end 215' opposite to the stator core 213' side while being inserted into the frame through hole. The grommet 221' includes a main body part 221a' having an insertion hole through which the winding extension part 213b' is inserted, and a bottom receiving part 221b extending from the outside of the main body part 221a' in a direction crossing the direction in which the insertion hole extends. ' and has. The grommet 221' has a side wall part 221c' extending from the outer edge of the bottom receiving part 221b' toward the control board 218' along the direction in which the insertion hole extends.

Rotating shaft 211', rotor 212', stator winding 213a', front frame end 214', front body part 214a', front peripheral wall part 214b', rear body part 215a', heat sink part 215c', front bearing 216', electronic Descriptions of the component 219', the cover 220', and the enlarged diameter portion 221d will be omitted.

Even if solder balls are generated during soldering between the control board 218' and the winding extension part 213b', the solder balls can be confined within the space formed by the grommet 221' and the control board 218'. Can be done. As a result, solder balls can be prevented from scattering.

By applying the grommet 221' shown in Comparative Example #2 (Fig. 18) to the terminal pin 5' of the circuit board 4' of Comparative Example #1 (Fig. 17), the terminal pin 5' and the circuit board 4' are It is possible to prevent flux and solder balls from scattering when electrically connecting them by soldering.

However, the configuration in which the grommets 221' are attached as in Comparative Example #2 requires the work to attach the same number of grommets 221' as the terminal pins 5', which increases the number of man-hours and reduces work efficiency. This is not preferable because the increase in the number of points increases the cost of the fan motor.

In this regard, in this embodiment, in the part of the circuit board opposite to the through-hole to which soldering is performed, there is a through-hole into which the terminal pin to be soldered to the through-hole is inserted, and a top part surrounding this through-hole. By having the ribs that come into contact with the circuit board, it is possible to prevent solder from flowing into the surface opposite to the surface to which soldering is performed, and the connection between the terminal pin and the circuit board can be prevented without increasing the number of parts. Prevents flux and solder balls from scattering during soldering.

FIG. 19 is a sectional view showing a configuration example of Comparative Example #3, and is a sectional view of an insert fitting and a mold shown in Japanese Patent Application Laid-Open No. 05-269791. In FIG. 19, the insert fitting 310' inserted into the cavity of the mold 330' is brought into close contact with the inner surface 331' of the mold 330' over the entire circumference by clamping the mold. Description of the resin material 320' and the resin surface 320a' will be omitted.

As a result of this, the pressure contact portion between the protrusion 312' and the mold inner surface 331' seals, thereby preventing resin burrs from forming on the exposed surface 311' side of the metal insert 310'.

By applying the annular protrusion 312' shown in Comparative Example #3 (Fig. 19) to the end of the bearing supporting cylinder part 17' of Comparative Example #1 (Fig. 17), the bearing supporting cylinder part 17' is improved. It is possible to prevent resin burrs from forming on the end face.

However, in the method for manufacturing a resin molded product having an insert fitting according to Comparative Example #3, the annular protrusion 312' formed on the outer diameter portion of the exposed surface 311' of the insert fitting 310' is connected to the inner surface 331' of the mold 330'. Since the bearing support cylinder part 17' corresponding to the insert fitting 310' is pressed with a crushing margin, if the radial thickness dimension of the bearing support cylinder part 17' is small, there is a possibility that the bearing support cylinder part 17' may be deformed. In a small axial fan, it is necessary to downsize the bearing support cylinder part 17', and the radial thickness of the bearing support cylinder part 17' is inevitably small. Easy to deform. If the bearing supporting cylinder part 17' is deformed, a problem arises in that the bearing cannot be mounted on the inner peripheral surface of the bearing supporting cylinder part 17'.

In this regard, in this embodiment, one or more annular recesses are provided on both end faces of the bearing holder to prevent synthetic resin from entering, so even in a downsized fan motor, deformation of the bearing holder is prevented. Therefore, resin burrs can be prevented from being formed on the inner circumferential surface of the bearing holder.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and various changes can be made without departing from the spirit thereof.

As described above, the fan motor according to the embodiment includes a cylindrical bearing holder that is insert-molded in the base part that is integrated into the housing, a stator that is attached to the outer periphery of the bearing holder, and an electrical connection with the coil of the stator. A bearing holder comprising: a circuit board connected to the base portion and mounted on the opposite side of the bearing holder; and a synthetic resin that seals the bearing holder, the stator, and the circuit board, leaving both end faces of the bearing holder. Both end surfaces have one or more annular recesses. As a result, burrs are not generated at both ends of the bearing holder due to sealing, and the number of work steps is not increased.

Further, the annular recess has an acute-angled cross-sectional shape on the side farthest from the end surface of the bearing holder in the axial direction. Thereby, an annular recess can be easily realized.

Further, the annular recess has a substantially arc-shaped cross section on the side farthest from the end surface of the bearing holder in the axial direction. Thereby, an annular recess can be easily realized.

Moreover, the inner circumferential surfaces of both end surfaces of the bearing holder have a tapered shape in which the diameter becomes narrower as the inner circumferential surface goes inside from the end surface side. This makes it easy to attach the bearing to the bearing holder.

Furthermore, the present invention is not limited to the above embodiments. The present invention also includes configurations in which the above-mentioned components are appropriately combined. Moreover, further effects and modifications can be easily derived by those skilled in the art. Therefore, the broader aspects of the present invention are not limited to the embodiments described above, and various modifications are possible.

1 fan motor, 11 housing, 12 base part, 12d through hole, 12e, 12f, 12g rib, 13 spoke, 14 wide part, 15 connector housing, 15b gate opening, 15c rib, 16 connector pin, 17 bearing holder, 21 stator , 22 stator core, 23 insulator, 24 terminal pin, 25 coil, 26 circuit board, 26a disc portion, 26d extension portion, 31 bearing, 32 rotating shaft, 33 grease holding plate, 34 sealing grease, 35 preload spring, 36 Retaining ring, 41 Rotor yoke, 42 Magnet, 43 Hub, 44 Vane, 51 Synthetic resin, 91, 92 Mold

Claims (4)

housing and
a base portion fixed to the housing;
a cylindrical bearing holder fixed to the base portion;
a stator attached to the outer periphery of the bearing holder;
a circuit board electrically connected to the coil of the stator and mounted on the opposite side of the stator across the base portion in the axial direction ;
a synthetic resin that seals the bearing holder, the stator, and the circuit board, leaving both end surfaces of the bearing holder;
Equipped with
Both end surfaces of the metal bearing holder have one or more annular recesses;
fan motor. The annular recess has an acute-angled cross-sectional shape on the side farthest from the end surface of the bearing holder in the axial direction.
The fan motor according to claim 1. The annular recess has a substantially arcuate cross-sectional shape on the side farthest from the end surface of the bearing holder in the axial direction;
The fan motor according to claim 1. The inner circumferential surfaces of both end surfaces of the bearing holder are tapered in diameter so that the diameter becomes smaller as the inner peripheral surface goes from the end surface side to the inside.
A fan motor according to any one of claims 1 to 3.

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