Fan motor

Abstract

The fan motor (1) of the embodiment includes a bearing housing (17), a stator (21), a circuit board (26), and a synthetic resin (51). The bearing housing (17) is insert-molded in a base portion (12) integrated with a cover (11) and a connector cover (15), and is cylindrical. The stator (21) is attached to the outer periphery of the bearing housing (17). The circuit board (26) is electrically connected to the coil (25) of the stator (21), and is attached to the surface of the base portion (12) opposite to the bearing housing (17), and extends from the base portion (12) to the connector cover (15). The synthetic resin (51) seals the bearing housing (17), the stator (21), and the circuit board (26) except for the both end faces of the bearing housing (17). The connector cover (15) has a gate (15b) through which the synthetic resin (51) is injected during sealing, and a rib (15c) located on the opposite side of the gate (15b) across the circuit board (26), and the top of the rib (15c) abuts against the circuit board (26).

Description

Background Art

[0001] A fan motor is a device that cools the interior of a personal computer, OA (office automation) equipment, etc. by rotating a fan (blade) to utilize wind power to discharge the heat generated inside to the outside.

[0002] In order to be used even in places where water or oil splashes or there is a lot of dust, a fan motor in which the internal stator and circuit board are sealed (molded) with synthetic resin has been proposed (for example, refer to Patent Document 1, etc.). It should be noted that this fan motor is of a type that is electrically connected to the outside using leads, but there is also a fan motor that uses a connector instead of a lead to be electrically connected to the outside (for example, refer to Patent Document 2). This fan motor has a structure in which the connector protrudes radially outward from the side of the fan cover, and the connector pins arranged inside the connector are connected to the circuit board. When sealing is performed in a cover provided with such a connector, due to the ease of contact with the outside, it is often the case that a gate of synthetic resin is provided near the connector.

[0003] Prior Art Documents

[0004] Patent Documents

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 2001-128408

[0006] Patent Document 2: International Publication No. 2019 / 112245 Summary of the Invention

[0007] Problems to be Solved by the Invention

[0008] However, when injecting synthetic resin from the gate near the connector after the stator and circuit board are surrounded by a mold, due to the injection pressure of the injected synthetic resin, the circuit board will deform. In the case where the deformation is large, there is a risk of the following adverse conditions occurring: cracks are generated in the welding part of the connector pins, or the welding part peels off.

[0009] The present invention has been completed in view of the above, and its object is to provide a fan motor that can prevent the circuit board from deforming even when the connector cover is integrally formed with the cover and the gate of the synthetic resin is arranged near the connector.

[0010] Means for Solving the Problems

[0011] To solve the above problems and achieve the object, a fan motor according to one aspect of the present invention includes a bearing housing, a stator, a circuit board, and a synthetic resin. The bearing housing is insert-molded in a base portion integrated with a cover and a connector cover, and has a cylindrical shape. The stator is attached to the outer periphery of the bearing housing. The circuit board is electrically connected to the coil of the stator, and is attached to a surface of the base portion opposite to the bearing housing, and extends from the base portion to the connector cover. The synthetic resin seals the bearing housing, the stator, and the circuit board except for both end faces of the bearing housing. The connector cover has: a gate for injecting the synthetic resin during sealing; and a rib located on the opposite side of the gate with respect to the circuit board, and a top portion of the rib abuts against the circuit board.

[0012] The fan motor according to one aspect of the present invention can prevent deformation of the circuit board even when the connector cover is integrally formed with the cover and the gate of the synthetic resin is disposed near the connector. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 FIG. 1 is an external perspective view showing a configuration example of a fan motor according to an embodiment.

[0014] Figure 2 FIG. 2 Figure 1 is a top view of the fan motor.

[0015] Figure 3 FIG. 3 Figure 2 is a sectional view taken along line A-A of the fan motor.

[0016] Figure 4 FIG. 4 is a top view showing a state in which a stator is attached in a bearing housing insert-molded in a base portion integrally formed with a cover.

[0017] Figure 5 FIG. 5 Figure 4 is a bottom view of the fan motor.

[0018] Figure 6 FIG. 6 Figure 5 is an enlarged view of a through hole and a rib vicinity.

[0019] Figure 7 FIG. 7 Figure 5 is a sectional view taken along line B-O-B of the fan motor.

[0020] Figure 8 FIG. 8 is a bottom view showing a state in which a circuit board is attached in the state of FIG. 7. Figure 5 is a sectional view taken along line B-O-B of the fan motor.

[0021] Figure 9 FIG. 9 Figure 8 is a sectional view taken along line B-O-B of the fan motor.

[0022] Figure 10is a sectional view showing an enlarged range V1 of Figure 9 The sectional view shows an enlarged range V1 of

[0023] Figure 11 is a sectional view showing a state in which a base portion, a bearing housing, a stator, and a circuit board are sealed with a mold.

[0024] Figure 12 is a view (bottom view) when one end portion of the bearing housing is observed from the axial direction.

[0025] Figure 13 is Figure 12 Y - Y sectional view of

[0026] Figure 14 is a view (top view) when the other end portion of the bearing housing is observed from the axial direction.

[0027] Figure 15 is Figure 14 Y - Y sectional view of

[0028] Figure 16 is a sectional view of the fan motor passing through the connector cover.

[0029] Figure 17 is a sectional view showing the configuration example of Comparative Example #1.

[0030] Figure 18 is a sectional view showing the configuration example of Comparative Example #2.

[0031] Figure 19 is a sectional view showing the configuration example of Comparative Example #3. Detailed Description of the Invention

[0032] Hereinafter, the fan motor of the embodiment will be described with reference to the drawings. It should be noted that the present invention is not limited to this embodiment. In addition, the dimensional relationships between the elements in the drawings, the ratios of the elements, etc. may sometimes be different from the actual ones. Sometimes, there are also parts with different dimensional relationships and ratios between the drawings. In addition, the content described in one embodiment or modification is generally applicable to other embodiments and modifications as well.

[0033] Figure 1 is an external perspective view showing the configuration example of the fan motor 1 of one embodiment. For convenience, the axial direction (rotation axis direction) of the fan motor 1 is set as the Z - axis direction, and the two sides orthogonal to the long - dimension direction of the cover 11 are set as the X - axis direction and the Y - axis direction respectively. Figure 2 is Figure 1 Top view of the fan motor 1 of Figure 3 is Figure 2 A - A sectional view of the fan motor 1 of

[0034] Figure 4It is a plan view showing a state in which a stator 21 is attached to a bearing housing 17 in which an insert is molded in a base portion 12 integrally formed with a cover 11. Figure 5 It is Figure 4 a bottom view of the fan motor 1. Figure 6 It is Figure 5 an enlarged view of the vicinity of the through-hole 12d and the rib 12e. Figure 7 It is Figure 5 a B - O - B cross-sectional view of the fan motor 1.

[0035] Figure 8 It shows a state in which Figure 5 a circuit board 26 is attached. It is a bottom view. Figure 9 It is Figure 8 a B - O - B cross-sectional view of the fan motor 1. Figure 10 It is Figure 9 a cross-sectional view showing an enlarged view of the range V1.

[0036] Figure 11 It is a cross-sectional view showing a state in which the base portion 12, the bearing housing 17, the stator 21, and the circuit board 26 are sealed by molds 91 and 92. Figure 12 It is a view (bottom view) showing the end of the bearing housing 17 when viewed from the axial direction on one side (the mold 92 side). Figure 13 It is Figure 12 a Y - Y cross-sectional view. Figure 14 It is a view (plan view) showing the end of the bearing housing 17 when viewed from the axial direction on the other side (the mold 91 side). Figure 15 It is Figure 14 a Y - Y cross-sectional view. Figure 16 It is a cross-sectional view of the fan motor 1 passing through the connector cover 15.

[0037] Hereinafter, the structure of the fan motor 1 will be described according to the manufacturing process.

[0038] (Manufacture of the cover)

[0039] Mainly in Figures 1 to 10 a state in which a hollow cylindrical bearing housing 17 made of a non-magnetic metal material such as brass is inserted, a cover 11, a base portion 12, spokes 13 (including a wide portion 14), and a connector cover 15 are integrally formed by injection molding of a thermoplastic resin.

[0040] The cover 11 is provided with a frame portion 11a that constitutes an outer frame, a hollow cylindrical wind tunnel portion 11b, and substantially quadrilateral flanges 11c located at both axial end faces of the wind tunnel portion 11b. Insertion holes 11d for inserting screws for assembly or the like are provided at the four corners of the flange 11c. A base portion 12 and a plurality of spokes 13 (including wide-width portions 14) are provided on one axial end side of the wind tunnel portion 11b, and a connector cover 15 is integrally formed at a part of the outer peripheral portion of the cover 11. The connector cover 15 is provided with a frame portion 15a connected to the cover 11, and a plurality of connector pins 16 are integrally formed and arranged inside it in an insert molding manner.

[0041] The base portion 12 has an annular ring portion 12a, and a bearing seat 17 is arranged at its center. A cylindrical outer peripheral wall 12b is formed at the outer peripheral edge of the ring portion 12a, and one axial end of the outer peripheral wall 12b is open. In addition, notches 12c for engaging with convex portions 26b ( Figure 8 ) formed at the outer peripheral edge of the circuit board 26 are formed at multiple places on the outer peripheral wall 12b.

[0042] The spokes 13 (including wide-width portions 14) are arranged along the circumferential direction on the outer peripheral surface of the outer peripheral wall 12b, connecting the outer peripheral surface of the outer peripheral wall 12b and the inner peripheral surface of the frame portion 11a of the cover 11. In addition, one of the spokes 13 is provided as a wide-width portion 14 with a width wider than that of the other spokes 13, extending toward the connector cover 15, and an extension portion 26d of the circuit board 26 is arranged at this part.

[0043] When the base portion 12 is molded, through holes 12d for inserting a plurality of terminal pins 24 of an insulator 23 disposed in the stator 21 are formed in the base portion 12, and ribs 12e ( Figure 5 , Figure 6 ) surrounding the through holes 12d are integrally formed on the side where the circuit board 26 is disposed. The rib 12e is formed to surround the through hole 12d and the bearing seat 17. In addition, the through holes 12d formed in the base portion 12 are formed in a conical shape with a diameter decreasing as it approaches the side where the circuit board 26 is disposed. The functions of the rib 12e and the through holes 12d will be described later.

[0044] (Manufacture of stator, Assembly of stator, Assembly of circuit board)

[0045] Mainly in Figures 1 to 10 , the stator core 22 that constitutes the stator 21 is formed by laminating a plurality of thin plate-like chips in the axial direction. The stator core 22 includes an annular core back 22a and a plurality of teeth 22b that radially extend outward in a radial direction from the core back 22a. The chips are made of a soft magnetic electromagnetic steel sheet or the like through stamping.

[0046] Insulators 23 made of insulating synthetic resin materials are respectively attached from both axial sides of the stator core 22, and the coils 25 are wound around the respective teeth 22b with the insulators 23 interposed therebetween. The ends of the coils 25 are wound and connected to the terminal pins 24 disposed on one axial side of the insulators 23 and are welded (joined) to form the stator 21.

[0047] 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 seat 17. At this time, the terminal pins 24 are respectively inserted through the through holes 12d formed in the annular portion 12a of the base portion 12 ( Figures 4 to 7 ).

[0048] After that, the circuit board 26 on which electronic components and the like are mounted is attached from the opening of the outer peripheral wall 12b of the base portion 12 ( Figures 8 to 10 ). The circuit board 26 has a circular plate portion 26a and an extension portion 26d extending radially outward from a part of the outer peripheral edge of the circular plate portion 26a, and convex portions 26b protruding radially outward are formed at multiple locations on the outer periphery of the circular plate portion 26a. The convex portions 26b are positioned by engaging with the notches 12c formed in the outer peripheral wall of the base portion 12 ( Figure 5 ).

[0049] When the circuit board 26 is attached, the tips of the respective terminal pins 24 are inserted through the through holes 12d formed in the outer peripheral wall 12b of the base portion 12 from the opening, and then are inserted through the through holes 26c of the pad portions of the wiring pattern formed on the circuit board 26. Similarly, the tips of the respective connector pins 16 are inserted through the through holes 26e of the pad portions of the wiring pattern formed on the circuit board 26 ( Figure 16 ). And the tips of the terminal pins 24 protruding from the pad portions of the wiring pattern of the circuit board 26 and the tips of the connector pins 16 are respectively welded.

[0050] On the other hand, the through holes 12d and the ribs 12e integrally formed when the base portion 12 is molded serve to prevent the splashing of the solder flux and solder balls. That is, when the terminal pins 24 and the wiring pattern of the circuit board 26 are electrically connected by welding, since the solder flux boils due to the heat during welding, the solder flux and solder balls sometimes splash. Even so, since the ribs 12e are formed so as to surround the through holes 12d, the solder flux and solder balls remain inside the ribs 12e and are prevented from splashing to the surroundings.

[0051] In addition, the ribs 12e are connected to other ribs 12f on the base portion 12 surrounding the end of the bearing seat 17 ( Figure 6 ). Thereby, the contact between the circuit board 26 and the ribs 12e can be stably performed, and the splashing of the solder flux and solder balls during welding can be more effectively prevented.

[0052] The through-hole 12d formed in the base portion 12 is formed in a conical shape with a diameter that decreases as it approaches the side where the power supply circuit board 26 is disposed. Therefore, even if the solder that forms the solder legs by flowing through the through-hole 26c of the circuit board 26 when the welding terminal pins 24 are welded may flow into the through-hole 12d of the base portion 12, the solder remains inside the rib 12e. Moreover, since the through-hole 12d is formed in a conical shape, it functions as a tapered seal to prevent the solder from flowing out of the through-hole 12d.

[0053] (Sealing achieved by synthetic resin)

[0054] Mainly in Figures 11 to 16 Among them, the stator 21 to which the circuit board 26 is connected is disposed between the molds 91 and 92, and transfer molding using, for example, epoxy resin as the synthetic resin 51 is performed. All the outer peripheral surfaces of the stator core 22, the coil 25, and the circuit board 26 on which the electronic components are mounted are sealed by the epoxy resin.

[0055] The gate (resin injection gate) 15b of the epoxy resin injected into the molds 91 and 92 is disposed at the connector ( Figure 5 , Figure 16 ). The epoxy resin injected into the molds 91 and 92 from the gate 15b at a specified injection pressure collides with the inside of the cover 11 and then separates and spreads in all directions. Among the epoxy resin spreading in all directions, the epoxy resin flowing in the direction of the circuit board 26 presses the surface of the circuit board 26 on the gate 15b side (for convenience, referred to as the gate surface of the circuit board 26). Therefore, the circuit board 26 is deformed by the injection pressure of the resin.

[0056] The connector pins 16 are welded to the wiring pattern of the circuit board 26. Therefore, stress concentrates on the welded portion, and the rib 15c formed integrally with the connector cover 15 inside the connector cover 15 abuts against the surface of the circuit board 26 opposite to the surface on the gate 15b side (for convenience, referred to as the back surface of the circuit board 26). Therefore, the rib 15c abutting against the back surface of the circuit board 26 prevents the circuit board 26 from being deformed by the injection pressure of the epoxy resin. It should be noted that since two rows of ribs 15c are provided along the arrangement direction of the connector pins 16 with the connector pins 16 interposed therebetween, the circuit board 26 (extension portion 26d) at the root of the connector pins 16 can be more effectively prevented from being deformed.

[0057] Since the vicinity of the gate 15b is most affected by the injection pressure of the epoxy resin, ribs 15c are formed inside the connector cover 15 and the ribs 15c abut against the back surface of the circuit board 26. However, deformation is also prevented in the portions other than the inside of the connector cover 15. For example, ribs 12g abutting against the back surface of the circuit board 26 are also formed on the back surface of the circular plate portion 26a, preventing the circuit board 26 from being deformed by the injection pressure of the epoxy resin.

[0058] On the other hand, annular recesses (grooves) 17a, 17b are formed at both axial end faces of the bearing seat 17 that abuts against the molds 91, 92( Figures 12 to 15 ). In the present embodiment, concentric multi-row (two-row) annular recesses 17a are formed at the end face on one axial side (the mold 92 side) of the bearing seat 17( Figure 12 , Figure 13 ), and a single-row annular recess 17b is formed at the end face on the other axial side (the mold 91 side) of the bearing seat 17( Figure 14 , Figure 15 ). It should be noted that the illustrated annular recesses 17a, 17b are provided such that the side axially away from the end face of the bearing seat 17 is acute in cross-sectional shape, but it may also be provided such that the side axially away from the end face of the bearing seat 17 is substantially arc-shaped in cross-sectional shape.

[0059] It is manufactured in such a way that the axial height dimension of the stator 21 is within a specified dimension range when the molds 91, 92 are closed. However, when a small gap is generated between the axial end faces of the bearing seat 17 and the molds 91, 92 due to dimensional deviations, the epoxy resin injected into the cavities of the molds 91, 92 will enter the small gap generated between the axial end faces of the bearing seat 17 and the molds 91, 92. However, the epoxy resin that enters the small gap will enter the annular recesses 17a, 17b formed at the end faces of the bearing seat 17 and fill the annular recesses 17a, 17b, so it will not reach the inner peripheral surface of the bearing seat 17.

[0060] In this way, the epoxy resin that enters the small gap generated between the axial end faces of the bearing seat 17 and the molds 91, 92 will enter and fill the annular recesses 17a, 17b formed at the end faces of the bearing seat 17. As a result, the resin overflow will not reach the inner peripheral surface of the bearing seat 17, and thus it will be easy to mount the bearing 31 on the bearing seat 17 later. It should be noted that the inner peripheral surfaces 17c, 17d of both end faces of the bearing seat 17 are tapered such that the diameter decreases as it enters the interior from the end face side. Therefore, when mounting the bearing 31, it is easy to enter the inner surface of the bearing seat 17 and is easy to mount.

[0061] (Manufacture and mounting of the rotor)

[0062] Mainly at Figures 1 to 3In the embodiment, a protrusion 41a is formed in the center of a cup-shaped rotor yoke 41 made of a soft magnetic material by inner edge flanging, and the rotating shaft 32 is pressed into the protrusion 41a. Then, the rotor yoke 41 connected with the rotating shaft 32 is insert-molded, and a cup-shaped hub 43 and a plurality of blades 44 on the outer peripheral surface of the hub 43 are integrally formed on the outer periphery of the rotor yoke 41 by injection molding of a thermoplastic resin. In addition, an annular magnet 42 is fixed to the inner peripheral surface of the rotor yoke 41.

[0063] On the other hand, two bearings 31 are fitted to the bearing housing 17 from both ends of the axial direction of the bearing housing 17 with a preload spring 35 sandwiched therebetween, and the rotating shaft 32 of the rotor is rotatably supported by the bearings 31. A grease retaining plate 33 is attached to the rotating shaft 32, and a sealing grease 34 is filled in the grease retaining plate 33. A retaining ring 36 is attached to the end side of the rotating shaft 32 on the opposite side to the rotor yoke 41. The sealing grease 34 can achieve waterproofing of the bearing 31.

[0064] <Comparative Example>

[0065] Figure 17 2 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. Figure 17 In the embodiment, a cover portion 18' is provided which surrounds the outer periphery of a plurality of blades 12' of a rotor 6', and a rotating shaft 13' of the rotor 6' is rotatably supported by bearings 15' and 16' housed in a bearing support cylinder 17'. In addition, the structure is as follows: a molded portion 24' is formed by molding with epoxy resin in a state where a stator 1', a circuit substrate 4' including electronic components, and a lead wire 21' are housed in a stator side housing 14', and a magnetic pole surface 2b' of a stator magnetic pole is also covered by the molded portion 24'.

[0066] The control circuit on the circuit substrate 4' is electrically connected to the coil 3' by winding the lead wire of the coil 3' around the terminal pin 5' that passes through the through hole 4a' of the circuit substrate 4' and is welded to the electrode on the circuit substrate 4'. Therefore, when the terminal pin 5' is electrically connected to the circuit substrate 4' by welding, the flux may boil due to the heat during welding, so there is a risk of spattering of the flux and solder beads.

[0067] In addition, although the end face of the cylindrical portion 17' for bearing support is in close contact with the inner surface of the mold, if a minute gap is generated between the end face of the cylindrical portion 17' for bearing support and the inner surface of the mold, the molten resin will enter this minute gap to cause resin overflow. If this resin overflow stays on the end face of the cylindrical portion 17' for bearing support, there is no problem. However, if the resin overflow reaches the inner peripheral surface of the cylindrical portion 17' for bearing support, the bearings 15' and 16' cannot be fitted onto the inner peripheral surface of the cylindrical portion 17', and an operation for removing the excess resin overflow will be required.

[0068] Regarding the iron core 2', salient pole portion 2a', coil 3', rotor-side housing 7', cup-shaped member 8', cylindrical portion 8a', bottom wall portion 8b', through hole 8c', blade mounting hub 9', cylindrical portion 9a', bottom wall portion 9b', rotor magnet 10', bushing 11', substrate accommodating portion 19', web 20', lead wire accommodating groove 22', and communication path 23', no description will be given.

[0069] Figure 18 It is a cross-sectional view showing an arrangement example of Comparative Example #2, and is a cross-sectional view of a rotating electric machine passing through the rotating shaft as shown in Japanese Patent Laid-Open No. 2018-007303. In Figure 18 this, the rotating electric machine as the electric machine includes: a rear end frame 215' formed with a frame through hole; a coil extension portion 213b'; and a control substrate 218' welded to the coil extension portion 213b'. In addition, a grommet 221' provided on the side opposite to the stator core 213' side of the rear end frame 215' in a state of being inserted into the frame through hole is also provided. The grommet 221' has: a main body portion 221a' formed with an insertion through hole for inserting the coil extension portion 213b'; and a bottom receiving portion 221b' extending from the outside of the main body portion 221a' in a direction intersecting with the direction in which the insertion through hole extends. The grommet 221' has a side wall portion 221c' extending from the outer edge portion of the bottom receiving portion 221b' toward the control substrate 218' side in the direction in which the insertion through hole s extends.

[0070] Regarding the rotating shaft 211', rotor 212', stator coil 213a', front end frame 214', front end main body portion 214a', front end peripheral wall portion 214b', rear end main body portion 215a', heat dissipation portion 215c', front end bearing 216', electronic component 219', cover 220', and diameter enlargement portion 221d, no description will be given.

[0071] Even if beads are generated during the welding of the control substrate 218' and the coil extension portion 213b', the beads can be enclosed within the space formed by the grommet 221' and the control substrate 218'. As a result, bead splash can be prevented.

[0072] It is conceivable to apply the grommet 221' shown in Comparative Example #2 ( Figure 18 ) to the terminal pins 5' of the circuit board 4' in Comparative Example #1 ( Figure 17 ) to prevent the splash of solder flux and solder balls when the terminal pins 5' are electrically connected to the circuit board 4' by soldering.

[0073] However, in a structure where the grommet 221' is attached as in Comparative Example #2, operations for attaching the terminal pins 5' and the same number of grommets 221' are required, which reduces the operation efficiency due to an increase in operation man-hours, and the number of components increases. As a result, the cost of the fan motor increases, so it is not preferable.

[0074] Regarding this point, in the present embodiment, a through-hole and ribs are provided in a portion facing the through-hole for soldering to the circuit board. The through-hole allows the terminal pins to be soldered to the through-hole to be inserted therethrough, and the ribs surround the through-hole. The top of the ribs abuts against the circuit board, thereby preventing the inflow of solder to the surface opposite to the soldering surface and preventing the splash of solder flux and solder balls when the terminal pins are soldered to the circuit board without increasing the number of components.

[0075] Figure 19 It is a cross-sectional view showing a configuration example of Comparative Example #3 and is a cross-sectional view of an insert metal part and a mold shown in Japanese Patent Laid-Open No. 05-269791. In Figure 19 , the insert metal part 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 with the annular protrusion 312' having an appropriate amount of crushing by mold clamping. Regarding the resin part 320' and the resin surface 320a', description is omitted.

[0076] Thus, sealing is performed using the crimping portion between the protrusion 312' and the inner surface 331' of the mold, and as a result, the generation of resin flash on the exposed surface 311' side of the insert metal part 310' is prevented.

[0077] It is conceivable to apply the annular protrusion 312' shown in Comparative Example #3 ( Figure 19 ) to the end of the bearing support cylinder part 17' in Comparative Example #1 ( Figure 17 ) to prevent the generation of resin flash on the end face of the bearing support cylinder part 17'.

[0078] However, in the method for manufacturing a resin molded product having an insert metal part in Comparative Example #3, the annular protrusion 312' formed on the outer diameter portion of the exposed surface 311' of the insert metal part 310' is crimped to the inner surface 331' of the mold 330' with a crushing amount. Therefore, when the radial thickness dimension of the bearing support cylindrical portion 17' corresponding to the insert metal part 310' is small, there is a risk that the bearing support cylindrical portion 17' will be deformed. In a small axial fan, the bearing support cylindrical portion 17' also needs to be miniaturized, and the radial thickness dimension of the bearing support cylindrical portion 17' will inevitably be small, and the bearing support cylindrical portion 17' is likely to be deformed. When the bearing support cylindrical portion 17' is deformed, there will be a problem that the bearing cannot be mounted on the inner peripheral surface of the bearing support cylindrical portion 17'.

[0079] Regarding this point, in the present embodiment, one or more annular recesses are provided on both end faces of the bearing seat to prevent the synthetic resin from entering. Therefore, even in a miniaturized fan motor, resin overflow can be prevented from forming on the inner peripheral surface of the bearing seat without the bearing seat being deformed.

[0080] As described above, the embodiments of the present invention have been described, but the present invention is not limited to the above embodiments, and various changes can be made as long as the gist thereof is not deviated from.

[0081] As described above, the fan motor of the embodiment includes: a cylindrical bearing seat, insert molded in a base portion integrated with a cover and a connector cover; a stator, mounted on the outer periphery of the bearing seat; a circuit board, electrically connected to the coil of the stator, mounted on the surface of the base portion opposite to the bearing seat, and extending from the base portion to the connector cover; and a synthetic resin, sealing the bearing seat, the stator, and the circuit board except for both end faces of the bearing seat. The connector cover has: a gate for injecting the synthetic resin during sealing; and a rib located on the opposite side of the gate across the circuit board, and the top of the rib abuts against the circuit board. Thus, even when the connector cover is integrally formed with the cover and the gate of the synthetic resin is disposed near the connector, deformation of the circuit board can be prevented.

[0082] In addition, two rows of ribs are provided across the connector pins disposed inside the connector cover. Thus, deformation of the circuit board at the root of the connector pins can be more effectively prevented.

[0083] In addition, the base portion has other ribs whose tops abut against the circuit board. Thus, deformation of the circuit board at locations other than the connector can be prevented.

[0084] In addition, the present invention is not limited to the above-described embodiments. A solution formed by appropriately combining the above-described respective components is also included in the present invention. In addition, those skilled in the art can easily derive further effects and modification examples. Therefore, a broader solution of the present invention is not limited to the above-described embodiments and can be variously modified.

[0085] Description of Reference Numerals

[0086] 1: Fan motor; 11: Cover; 12: Base portion; 12d: Through hole; 12e, 12f, 12g: Ribs; 13: Spoke; 14: Wide portion; 15: Connector cover; 15b: Gate; 15c: Rib; 16: Connector pin; 17: Bearing seat; 21: Stator; 22: Stator core; 23: Insulator; 24: Terminal pin; 25: Coil; 26: Circuit board; 26a: Circular plate portion; 26d: Extension portion; 31: Bearing; 32: Rotating shaft; 33: Grease retaining plate; 34: Sealing grease; 35: Preloading spring; 36: Snap ring; 41: Rotor yoke; 42: Magnet; 43: Hub; 44: Blade; 51: Synthetic resin; 91, 92: Molds.

Claims

1. A fan motor, characterized in that, Comprising: A cylindrical bearing housing, insert-molded in a base portion integrated with a cover and a connector cover; A stator, attached to the outer periphery of the bearing housing; A circuit board, electrically connected to the coil of the stator, axially attached to the opposite side of the stator with the base portion interposed therebetween, extending from the base portion to the connector cover; and A synthetic resin, sealing the bearing housing, the stator, and the circuit board except for both end faces of the bearing housing, The connector cover has: a gate for injecting the synthetic resin during sealing; and ribs located on the opposite side of the gate across the circuit board, the top of the ribs abutting against the circuit board.

2. The fan motor according to claim 1, wherein Two rows of the ribs are provided across the connector pins disposed inside the connector cover.

3. The fan motor according to claim 1 or 2, wherein The base portion has other ribs whose tops abut against the circuit board.

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