Fan motor

Abstract

To provide a thin fan motor including a dust-proof and water-proof structure.SOLUTION: A fan motor according to an embodiment includes an impeller, a motor, a circuit board, a casing, and a cover. The impeller includes a hub, and multiple blades provided at the hub. The motor rotates the impeller. An electronic component for controlling driving of the motor is mounted on the circuit board. The casing houses the impeller and the motor therein. The cover is provided at one axial end of the casing. The circuit board is bonded to a recessed part formed at the other axial end of the casing to be placed therein. The electronic component is disposed in an opening formed at a part of the recessed part, and a part of the electronic component is exposed to the interior of the casing. A potting agent applied to the periphery of the electronic component enters a gap between the casing and the circuit board to seal the gap.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a fan motor. [Background technology]

[0002] 2. Description of the Related Art Conventionally, in electronic devices such as personal computers and mobile phones, a fan motor may be used to forcibly dissipate heat and cool the mounted electronic components in order to improve the heat dissipation performance.

[0003] In such electronic devices such as personal computers and mobile phones, it is difficult to secure a large space for incorporating a fan motor, and therefore there is a demand for smaller and thinner fan motors.

[0004] In response to such needs, thin fan motors (cooling fans) have been proposed (see, for example, Patent Document 1). In the fan motor described in Patent Document 1, the circuit board is placed in a receiving space provided on one side of the housing, thereby achieving a thin design. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] US Patent Application Publication No. 2015 / 0301567 Summary of the Invention [Problem to be solved by the invention]

[0006] However, the fan motor described in Patent Document 1 has a structure in which the soldering points of the circuit board and electronic components are exposed to the air flow path, which means that it cannot meet the requirements for waterproofing or dustproofing. In other words, if moisture or foreign matter gets inside the fan motor, there is a risk that the pins and terminals of the electronic components may short-circuit or corrode.

[0007] The present invention has been made in view of the above, and has an object to provide a thin fan motor having a dustproof and waterproof structure. [Means for solving the problem]

[0008] In order to solve the above-mentioned problems and achieve the object, one aspect of the present invention provides a fan motor comprising an impeller, a motor, a circuit board, a casing, and a cover. The impeller comprises a hub and a plurality of blades provided on the hub. The motor rotates the impeller. The circuit board is mounted with electronic components for driving and controlling the motor. The casing accommodates the impeller and the motor inside. The cover is provided at one axial end of the casing. The circuit board includes an area where an adhesive is applied and an area where the electronic components are mounted, and the area where the electronic components are mounted is surrounded by the area where the adhesive is applied. The circuit board is fitted in a recess formed at the other axial end of the casing. Using the adhesive The electronic component is placed in an opening formed in a part of the recess, with a part of the electronic component exposed to the inside of the casing. A potting agent applied around the electronic component penetrates into and seals the gap between the casing and the circuit board.

[0009] A fan motor according to one aspect of the present invention has a dustproof and waterproof structure and can be made thin. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a perspective view of the appearance of a fan motor according to one embodiment. [Figure 2] FIG. 2 is an exploded perspective view of the main components of the fan motor. [Figure 3] FIG. 3 is a cross-sectional view taken along the line XY-XY in FIG. [Figure 4] FIG. 4 is an enlarged cross-sectional view of a main part in FIG. [Figure 5] FIG. 5 is a perspective view of the casing and the circuit board. [Figure 6] FIG. 6 is a plan view of the casing and the circuit board. [Figure 7] FIG. 7 is a plan view showing a state in which the periphery of the electronic components of the circuit board exposed from the opening of the casing is sealed with a potting agent. [Figure 8] FIG. 8 is a bottom view of the casing. [Figure 9] FIG. 9 is a perspective view of the circuit board. [Figure 10] FIG. 10 is an external perspective view of a fan motor according to a comparative example. DETAILED DESCRIPTION OF THE INVENTION

[0011] Fan motors according to embodiments will be described below with reference to the drawings. Note that the present invention is not limited to these embodiments. Furthermore, the dimensional relationships and ratios of elements in the drawings may differ from the actual situation. The dimensional relationships and ratios may differ between the drawings. Furthermore, the content described in one embodiment or modification also applies, in principle, to other embodiments or modifications.

[0012] FIG. 1 is an external perspective view of a fan motor 1 according to one embodiment. FIG. 2 is an exploded perspective view of the main components of the fan motor 1. FIG. 3 is an XY-XY cross-sectional view of FIG. 1. FIG. 4 is an enlarged cross-sectional view of the main parts of FIG. 3. FIG. 5 is a perspective view of a casing 2 and a circuit board 6. FIG. 6 is a plan view of the casing 2 and the circuit board 6. FIG. 7 is a plan view showing a state in which the periphery of electronic components 7 of the circuit board 6 exposed from an opening 2g of the casing 2 is sealed with a potting agent 9. FIG. 8 is a bottom view of the casing 2. FIG. 9 is a perspective view of the circuit board 6.

[0013] 1 to 9, fan motor 1 according to one embodiment is a centrifugal fan (radial flow fan). Fan motor 1 includes a casing 2, a cover 3 attached to casing 2, and a motor 4 and impeller 5 disposed inside casing 2, with cover 3 provided at one axial end (upper end) of casing 2. Furthermore, a circuit board 6 made of flexible printed circuits (FPC) is disposed at the other axial end (lower end) of casing 2.

[0014] (About the structure of casing 2) The casing 2 is approximately square in plan view and has a base portion 2a and side walls 2r. One of the sides of the base portion 2a does not have a side wall 2r, but this part forms an opening between the cover 3 and the casing 2 and acts as an exhaust port 1b.

[0015] An impeller 5 and a motor 4 for rotating the impeller 5 are disposed inside the space formed between the cover 3 and the casing 2, and the space formed between the cover 3 and the casing 2 constitutes a flow path 2p through which air flows. A tongue 2q that protrudes toward the center is formed at one end of the flow path 2p on the exhaust port 1b side.

[0016] An annular portion 2o protruding in the axial direction is formed on the surface of one axial end of the base portion 2a, and a cylindrical bearing holder 2k with a bottom protruding in the axial direction is integrally formed at the center of the annular portion 2o. The portion of the base portion 2a surrounded by the annular portion 2o forms a circular portion 2c. A recess 2f is formed on the surface of the other axial end (in other words, the lower surface), and a cylindrical boss portion 2e is integrally formed within the recess 2f at the center of the base portion 2a.

[0017] Furthermore, the recess 2f is formed with a plurality of (three) through holes 2d and one opening 2g. The through hole 2d is a hole through which an end of the coil 4c of the motor 4 is inserted, and this through hole 2d is located outside the bearing holder 2k. The opening 2g is where an electronic component 7 (for example, a drive control IC) mounted on the circuit board 6 is placed.

[0018] The outer circumferential surface of each side wall 2r is formed with recesses 2s extending in the axial direction, and each recess 2s is formed with a protrusion 2t. The protrusion 2t engages with an opening 3c of a locking portion 3b provided on the cover 3.

[0019] The above-mentioned components (base portion 2a, side wall 2r, bearing holder 2k, recess 2f, boss portion 2e, protrusion 2t, etc.) are integrally formed by, for example, injection molding of resin.

[0020] (About the structure of Cover 3) The cover 3 attached to the casing 2 has a substantially square shape in a plan view. The cover 3 is manufactured, for example, by pressing a thin metal plate (e.g., SUS304 material). A circular opening 3a is formed in the center of the cover 3, which serves as the intake port 1a. A radially extending locking portion 3b is formed on each of three sides of the cover 3, and an opening 3c is formed at the location of each locking portion 3b.

[0021] After being pressed from a thin plate, the locking portions 3b are bent in a direction (90 degrees) perpendicular to the surface of the cover 3. Openings 3c formed in each locking portion 3b engage with protrusions 2t formed on the side surface of the casing 2, thereby attaching the cover 3 to one end of the casing 2 in the axial direction.

[0022] (Motor 4 structure) The motor 4 is, for example, a three-phase brushless DC motor, and is composed of a stator 4a and a rotor 4d. The stator 4a is composed of a stator core 4b in which a predetermined number of thin electromagnetic steel cores are stacked in the axial direction, and a coil 4c wound around the stator core 4b.

[0023] The stator core 4b has a ring-shaped core back and multiple (six in this embodiment) teeth extending radially from the outer periphery of the core back. The stator core 4b is coated with an insulating paint, and insulators are not attached to reduce the thickness, and coils 4c are wound around each tooth via the paint film. Note that if there is room for axial height restrictions, an insulator may be attached to the stator core 4b, and the coils 4c may be wound around each tooth via the insulator.

[0024] The rotor 4d is composed of a roughly cup-shaped rotor yoke 4h, a shaft 4f that is press-fitted into a through hole formed in the center of the rotor yoke 4h, and a ring-shaped magnet 4n that is arranged on the inner surface of the rotor yoke 4h, and the magnet 4n is bonded to the rotor yoke 4h by being glued, for example, with an adhesive.

[0025] The rotor yoke 4h has a generally cup-shaped annular first plane 4i at one axial end, an annular second plane 4k radially outward from the first plane 4i, and a cylindrical portion 4m extending to the other axial end (lower end) on the outer circumferential edge of the second plane 4k. The second plane 4k is located closer to the other axial end (lower end) than the first plane 4i, and the first plane 4i and the second plane 4k are connected by an inclined plane 4j.

[0026] The circular opening of the core back of the stator core 4b is fitted onto the outer peripheral surface of the bearing holding portion 2k, and the lowest end surface of the stator core 4b abuts against the step portion 2m formed on the bearing holding portion 2k, thereby positioning it in the axial direction.

[0027] A part of the lower end of the cylindrical portion 4m of the rotor yoke 4h and a part of the lower side of the coil 4c are located in a recess on the inside of the annular portion 2o of the casing 2, thereby achieving a thin axial direction.

[0028] A disk-shaped resin washer 4g with good sliding properties is placed on the bottom surface of the cylindrical bearing holder 2k, and a cylindrical bearing 4e with a through-hole in the center is provided inside the bearing holder 2k. The bearing 4e is, for example, a copper-based sintered oil-impregnated bearing, a sliding bearing impregnated with lubricating oil, and rotatably supports the shaft 4f.

[0029] (About the structure of Impeller 5) An impeller 5 is joined to the outer peripheral surface of the rotor yoke 4h. The impeller 5 is composed of a ring-shaped hub 5a and multiple blades 5b joined to the hub 5a. All of the blades 5b have the same shape and are evenly spaced in the circumferential direction. The hub 5a and the blades 5b are integrally formed, for example, by injection molding of resin.

[0030] The outer peripheral surface of the cylindrical portion 4m of the rotor yoke 4h and the inner peripheral surface of the ring-shaped hub 5a are bonded together with an adhesive. A recess 5c is formed in the lower surface of the root side of the blade 5b, which faces the hub 5a. A part of the upper end of the annular portion 2o of the casing 2 fits into this recess 5c, thereby reducing the axial thickness.

[0031] (Structure of circuit board 6) A circuit board 6 is disposed in a recess 2f formed at the other axial end (lower end) of the base portion 2a of the casing 2. A circular opening 6a is formed at one radial end of the circuit board 6, and a circular boss portion 2e formed at the other axial end (lower end) of the base portion 2a is inserted into the opening 6a. The other radial end of the circuit board 6 extends to the outside of the casing 2 via a notch 2b formed in part of the side wall 2r. Three through holes 6b are formed around the opening 6a, and these through holes 6b are through holes formed in the lands of the wiring pattern.

[0032] An electronic component 7 (e.g., a drive control IC) mounted on the circuit board 6 is inserted into an opening 2g formed in the recess 2f of the base portion 2a, and a portion of the electronic component 7 (e.g., a drive control IC) is exposed to the inside of the casing 2 (flow path 2p).

[0033] Each of the terminals (U phase, V phase, W phase) of the coils 4c wound around the stator core 4b of the motor 4 is inserted into a predetermined through-hole 2d formed in the base portion 2a, and the terminal of each coil 4c is inserted into a predetermined through-hole 6b formed in the circuit board 6, and then soldered to be electrically connected to the wiring pattern.

[0034] The soldered portion is housed in a recess 2f formed on the other end side of the base portion 2a, so that the soldered portion does not protrude from the lower end surface of the casing 2.

[0035] A circuit board 6 is disposed in a recess 2f formed at the other axial end (lower end) of the base portion 2a. To join the two together, an adhesive material 8 (e.g., double-sided tape) is applied to the openings 6a and through-holes 6b of the circuit board 6 where electronic components 7 and the like are mounted (the hatched areas in FIG. 9), and the circuit board 6 is attached to the recess 2f formed at the other end of the base portion 2a of the casing 2. At this time, the circuit board 6 is attached so that the positions of the through-holes 6b align, and the electronic components 7 (drive control ICs) mounted on the circuit board 6 are disposed in the opening 2g.

[0036] After the circuit board 6 is attached to the casing 2, a potting agent 9 (for example, a heat-dissipating silicone rubber-based potting agent) is applied around the electronic component 7 (drive control IC). By applying the potting agent 9, the pins of the drive control IC and the exposed wiring pattern are sealed, and the applied potting agent 9 also penetrates and permeates the gap between the circuit board 6 and the casing 2 to seal it.

[0037] Thereafter, the stator core 4b is attached to the bearing holder 2k of the casing 2, and the terminals of the coils 4c are inserted into the predetermined through-holes 2d and soldered to be electrically connected to the wiring pattern.

[0038] (Comparative Example) Fig. 10 is an external perspective view of a fan motor 1' according to a comparative example. In Fig. 10, the fan motor 1' of the comparative example has a fan shell 10' formed by a base plate 11' and a shell cover 12', and an internal space 100' is formed inside the fan shell 10'. The blades 30' exposed from an opening 120' in the fan shell 10' are disposed in the internal space 100' and rotated by a motor 20'.

[0039] The base plate 11' has a first surface facing the interior space 100' and a second surface opposite the first surface. A receiving space is formed in the second surface, and the PCB 40' is placed in the receiving space. The PCB 40' is formed flush with the second surface, thereby achieving a thin design.

[0040] PCB 40' has an annular substrate arranged coaxially with the rotation shaft of motor 20', an arc-shaped substrate arranged on the radial outer periphery, and a linear substrate connecting the two, and the annular substrate is provided with soldering points 411' at positions corresponding to holes 1022'. Electronic components 422' are arranged on the arc-shaped substrate, and soldering points 421' for connecting to cables are provided.

[0041] The fan motor 1' has soldering points 421' and electronic components 422' arranged in the air flow path, and the soldering points 421' and electronic components 422' are exposed, so the fan motor 1' does not have any waterproof or dustproof features. Therefore, if foreign matter or moisture gets inside the fan motor 1', there is a risk that problems such as short circuits or corrosion may occur in the electronic components 422' and cable pins and terminals.

[0042] In this regard, in the fan motor 1 of one embodiment shown in FIGS. 1 to 9, the circuit board 6 is attached to the casing 2 with an adhesive 8, and a potting agent 9 is applied around the electronic component 7 (drive control IC). This seals the pins of the drive control IC and the exposed wiring pattern, and the applied potting agent 9 also penetrates and seals the gap between the circuit board 6 and the casing 2. As a result, dustproof and waterproof effects are achieved even if foreign matter or moisture gets in. When the fan motor 1 is incorporated into an electronic device such as a personal computer or a mobile phone, and waterproof and dustproof functions are required depending on the application and usage environment, these requirements can be met.

[0043] Furthermore, the circuit board 6 has a structure in which a part of the electronic component 7 (for example, a drive control IC) mounted on the circuit board 6 is exposed to the air flow path inside the casing 2. Therefore, the electronic component 7 (for example, a drive control IC) can be effectively cooled by the fast air flow, and the thermal load on the electronic component 7 can be reduced.

[0044] Furthermore, the depth of the recess 2f in the casing 2 in which the circuit board 6 is placed is set to be greater than the thickness of the circuit board 6 plus the thickness of the soldering at the tip of the terminal of the coil 4c, so that the soldering point at the terminal of the coil 4c does not protrude beyond the casing 2, and interference with other components can be avoided.

[0045] Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications are possible without departing from the spirit of the present invention.

[0046] As described above, the fan motor according to the embodiment includes a hub, an impeller having a plurality of blades attached to the hub, a motor for rotating the impeller, a circuit board mounted with electronic components for driving and controlling the motor, a casing that houses the impeller and the motor, and a cover attached to one axial end of the casing, where the circuit board is attached to a recess formed in the other axial end of the casing, the electronic components are placed in an opening formed in part of the recess, and part of the electronic components are exposed to the inside of the casing, and a potting agent applied around the electronic components penetrates and seals the gap between the casing and the circuit board, thereby providing a dustproof and waterproof structure and allowing for a thin design.

[0047] The terminals of the coil wound around the motor are electrically connected to the wiring pattern formed on the circuit board by passing through a through hole formed in the casing and a through hole formed in the circuit board, and the through hole in the casing and the through hole in the circuit board are positioned opposite each other in the axial direction, which allows the terminals of the coil to be connected via a short path, making effective use of space and improving the electrical characteristics of the motor.

[0048] The casing and the circuit board are attached with an adhesive, which makes it easy to attach the circuit board.

[0049] The potting agent is a heat-dissipating silicone rubber, which not only provides dustproofing and waterproofing but also improves heat dissipation characteristics.

[0050] In addition, the motor has an insulating coating on the stator core, and the coils are wound without an insulator, which makes it possible to make the motor thinner by the thickness of the insulator.

[0051] The casing also has another recess on the surface axially opposite to the recess in which the circuit board is placed, and the rotor yoke and the lower ends of the coils of the motor are located inside the other recess, which makes it possible to reduce the thickness of the casing.

[0052] Furthermore, the present invention is not limited to the above-described embodiments. Configurations in which the above-described components are appropriately combined are also included in the present invention. Furthermore, 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 above-described embodiments, and various modifications are possible. [Explanation of symbols]

[0053] 1 fan motor, 1a intake port, 1b exhaust port, 2 casing, 2d through hole, 2f recess, 2g opening, 3 cover, 4 motor, 4c coil, 5 impeller, 5a hub, 5b blade, 6 circuit board, 6b through hole, 7 electronic component, 8 adhesive, 9 potting agent

Claims

1. an impeller having a hub and a plurality of blades provided on the hub; a motor for rotating the impeller; a circuit board on which electronic components for driving and controlling the motor are mounted; a casing that houses the impeller and the motor; a cover provided at one axial end of the casing; A fan motor comprising: the circuit board includes an area where an adhesive material is applied and an area where the electronic components are mounted; the area where the electronic component is mounted is surrounded by the area where the adhesive material is applied, the circuit board is attached to a recess formed at the other axial end of the casing using the adhesive; the electronic component is disposed in an opening formed in a part of the recess, and a part of the electronic component is exposed to the inside of the casing; The potting agent applied around the electronic components penetrates into the gap between the casing and the circuit board to seal it. Fan motor.

2. an end of the coil wound around the motor is inserted through a through hole formed in the casing and a through hole formed in the circuit board, and is electrically connected to a wiring pattern formed on the circuit board; the through hole of the casing and the through hole of the circuit board are arranged at positions opposite to each other in the axial direction; 2. The fan motor according to claim 1.

3. 3. The fan motor according to claim 1, wherein the potting agent is a heat-dissipating silicone rubber-based agent.

4. 4. The fan motor according to claim 1, wherein the motor has a stator core coated with an insulating paint and a coil wound therearound without an insulator.

5. 5. A fan motor according to claim 1, wherein the casing has another recess on a surface axially opposite to the recess in which the circuit board is disposed, and lower ends of the rotor yoke and coil of the motor are located inside the other recess.

Images