Axial Fan Motor

Abstract

To provide an axial flow fan motor which enables increase of a mounting area of a circuit board and further achieves improvement of heat radiation performance compared to a conventional axial flow fan motor.SOLUTION: A fan device (100) serving as an axial flow fan motor includes a hollow cylindrical casing (150 (200, 300)) in which a suction port (201) and an exhaust port (301) are respectively provided at one end as seen in an axis (X) direction and the other end as seen in the axis (X) direction; an impeller (210) which is housed in the casing (150) and has multiple blades (212); a motor (250) which is housed in the casing (150) and rotates the impeller (210); and multiple circuit boards (400, 500) which are arranged along the axis (x) direction at the side of the exhaust port (301) in the casing (150).SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] In recent years, as information devices have become more powerful, the power consumption of the electronic components inside those devices has been steadily increasing. Accordingly, fans used to cool electronic components in information devices such as servers, which require high power and functionality, are naturally required to have higher power output and improved cooling performance. Therefore, it is also necessary to cool the heat generated by the control board that drives the high-power fans, which is caused by the concentration of power on the control board.

[0003] To address this issue, conventionally, a fan motor has been disclosed that has a structure in which the control board is positioned approximately parallel to the central axis of rotation of the fan, so that the control board is positioned in the airflow that flows from the intake port of the frame to the exhaust port due to the rotating blades, and the airflow hits all or part of the control board (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2008 / 041353 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the control board described in Patent Document 1 is formed from a single T-shaped plate, and the upper limit of its mounting area is determined depending on the size of the fan, so it is not possible to further increase the mounting area, and there is a concern that it may be difficult to accommodate higher fan output.

[0006] Furthermore, because the mounting area of ​​the control board cannot be further increased, there is a limit to how large the extension section can be made, and therefore it is not possible to install all of the electronic components that generate a lot of heat in the extension section, making it difficult to further improve heat dissipation performance.

[0007] The present invention has been made in view of the above background, and has as its object to provide an axial fan motor which increases the mounting area of ​​the circuit board and has improved heat dissipation performance compared to conventional ones. [Means for solving the problem]

[0008] The above-mentioned problems are solved by the present invention, which provides an axial fan motor comprising: a hollow cylindrical casing having an intake port at one axial end and an exhaust port at the other axial end, an impeller having a plurality of blades housed in the casing, a motor housed in the casing for rotating the impeller, and a plurality of circuit boards arranged along the axial direction on the side of the casing that faces the exhaust port.

[0009] According to the present invention, it is possible to realize an axial fan motor that has an increased mounting area on a circuit board and has improved heat dissipation compared to conventional motors. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a perspective view showing an overall configuration of a fan device according to an embodiment of the present invention; [Figure 2] 1 is a perspective view showing the configuration of an upper casing and a lower casing of a fan device according to an embodiment of the present invention; [Figure 3] 2 is a cross-sectional view showing a configuration of a drive unit in the fan device according to the embodiment of the present invention; FIG. [Figure 4] 1A is a top view showing the configuration of a lower casing of a fan device according to an embodiment of the present invention, FIG. 1B is a side view, and FIG. 1C is a cross-sectional view taken along line AA in FIG. 1B. [Figure 5]1 is an exploded perspective view showing the configuration of two circuit boards in a fan device according to an embodiment of the present invention. [Figure 6] 1 is a perspective view showing a state in which two circuit boards are joined together in a fan device according to an embodiment of the present invention. [Figure 7] 2 is a bottom view showing two circuit boards attached to a lower casing in the fan device according to the embodiment of the present invention. FIG. [Figure 8] 10A and 10B are bottom views showing arrangement patterns of a circuit board attached to a lower casing according to another embodiment of the present invention. [Figure 9] FIG. 10 is a perspective view showing the configuration of a fan device according to another embodiment of the present invention, in which four circuit boards form sidewalls. DETAILED DESCRIPTION OF THE INVENTION

[0011] <Embodiment> Hereinafter, embodiments of the present invention will be described with reference to FIGS. 1 to 7. FIG. 1 is a perspective view showing the overall configuration of a fan device according to an embodiment of the present invention. FIG. 2 is a perspective view showing the configurations of an upper casing and a lower casing of a fan device according to an embodiment of the present invention. FIG. 3 is a cross-sectional view showing the configuration of a drive unit in a fan device according to an embodiment of the present invention. FIG. 4 is a top view (A), a side view (B), and an AA cross-sectional view (C) of (B) showing the configuration of the lower casing of a fan device according to an embodiment of the present invention. FIG. 5 is an exploded perspective view showing the configuration of two circuit boards in a fan device according to an embodiment of the present invention. FIG. 6 is a perspective view showing two circuit boards joined together in a fan device according to an embodiment of the present invention. FIG. 7 is a bottom view showing two circuit boards attached to the lower casing in a fan device according to an embodiment of the present invention.

[0012] In the description of the embodiments of the present invention, for convenience of explanation, the direction of arrow a along axis X will be referred to as the upper side or upward. Upper side or upward means the intake port side. The direction of arrow b along axis X will be referred to as the lower side or downward. Lower side or downward means the exhaust port side. Here, the direction of arrow ab will be referred to as the up-down direction, but this does not necessarily coincide with the up-down direction in the direction of gravity. Furthermore, the direction of arrow c away from axis X will be referred to as the outer circumferential side, the direction of arrow d approaching axis X will be referred to as the inner circumferential side, and the direction of arrow cd will be referred to as the radial direction.

[0013] The fan device 100, which serves as an axial fan motor in the embodiment of the present invention, is an axial fan that blows air in the direction of axis X. The fan device 100 has a casing 150 in which an upper casing 200 and a lower casing 300 are integrally joined together. The upper casing 200 and the lower casing 300 are connected to each other along the direction of axis X.

[0014] Upper casing 200 has a generally square cylindrical shape in plan view, and has an air intake 201 for drawing air into a hollow cylindrical air tunnel from above in the direction of axis X (the direction of arrow a). Upper casing 200 houses impeller 210 consisting of hub 211 and blades 212, and motor 250 (FIG. 3) for driving impeller 210 to rotate.

[0015] Upper casing 200 has four upper flanges 202 at its upper corners (in the direction of arrow a) and four lower flanges 203 at its lower corners (in the direction of arrow b). These upper flanges 202 and lower flanges 203 are provided with through holes through which bolts (not shown) for attaching to a predetermined device or housing are inserted.

[0016] The upper casing 200 includes a side wall 204 that surrounds the impeller 210 in the radial direction (direction of arrow cd), a motor base portion 205 formed on the exhaust port side, which is the lower end in the axial X direction, and fixed blades 206 consisting of a plurality of stator blades that connect the side wall 204 and the motor base portion 205 in the radial direction (direction of arrow cd).

[0017] The side wall 204, motor base 205, and multiple fixed blades 206 of the upper casing 200 are integrally formed by injection molding of synthetic resin (for example, polybutylene terephthalate resin (containing glass fiber)). Note that multiple spokes made of rod-shaped parts may be used instead of the fixed blades 206 connecting the side wall 204 and motor base 205.

[0018] The side wall 204 that constitutes the air tunnel portion of the upper casing 200 has a cylindrical shape centered on the axis X, and has an inner diameter that does not contact the outer peripheral ends of the blades 212 of the impeller 210. In other words, a predetermined gap is formed between the outer peripheral ends of the blades 212 of the impeller 210 and the inner peripheral surface of the side wall 204.

[0019] The side wall 204 of the upper casing 200 also functions as a guard portion that protects the impeller 210. Four upper flange portions 202 and four lower flange portions 203 are integrally formed with the side wall 204 on the upper side (direction of arrow a) and lower side (direction of arrow b) of the outer periphery of the side wall 204.

[0020] The motor base portion 205 is formed by a disk-shaped base portion 205a, a cylindrical outer wall 205b extending a predetermined length from the outer end of the base portion 205a upward (in the direction of arrow a) along the axis X, and a boss portion 205c protruding a predetermined length from the inner end of the base portion 205a upward (in the direction of arrow a) along the axis X.

[0021] The above-mentioned plurality of fixed blades 206 are integrally formed on the outer peripheral surface of the outer peripheral wall 205b of the motor base portion 205. In other words, the outer peripheral wall 205b of the motor base portion 205 is supported by the side wall 204 of the upper casing 200 via the plurality of fixed blades 206.

[0022] A hollow cylindrical bearing housing 207 made of a metal material is press-fitted onto the inner circumferential surface of the boss portion 205c of the motor base portion 205. The bearing housing 207 is press-fitted into the boss portion 205c, but this is not limiting, and the bearing housing 207 may be formed integrally with the motor base portion 205 in a state where it is inserted into the boss portion 205c.

[0023] A stator portion 260 is disposed on the outer peripheral surface of the bearing housing 207. However, this is not limitative, and the stator portion 260 may be attached directly to the motor base portion 205 without the bearing housing 207 being interposed therebetween.

[0024] The inner peripheral surface of bearing housing 207 has stepped portions on the upper side (direction of arrow a) and lower side (direction of arrow b) in the direction of axis X, and bearings 221, 222 are fitted to the stepped portions on the upper side (direction of arrow a) and lower side (direction of arrow b). Bearings 221, 222 are, for example, ball bearings. However, bearings 221, 222 are not limited to ball bearings, and various other bearings such as sleeve bearings may also be used.

[0025] Bearing 221 rotatably supports an upper side in the direction of axis X (direction of arrow a) relative to shaft 277 of rotor unit 270, and bearing 222 rotatably supports a lower side in the direction of axis X (direction of arrow b) relative to shaft 277. As a result, shaft 277 of rotor unit 270 is rotatably supported relative to stator unit 260.

[0026] Motor 250 is, for example, a single-phase brushless DC motor, and is composed of stator section 260 and rotor section 270. Stator section 260 has stator core 261 formed by a laminate of multiple electromagnetic steel sheet cores made of soft magnetic material, insulator 262 made of insulating material attached to stator core 261, and coil 263 wound around stator core 261 via insulator 262.

[0027] In this way, coil 263 is wound around stator core 261 via insulator 262, and therefore stator core 261 and coil 263 are insulated by insulator 262. Motor 250 is not limited to a single-phase brushless DC motor, and other motors such as a three-phase brushless DC motor may be used.

[0028] In stator core 261, the outer peripheral surface of bearing housing 207 is fitted onto the inner peripheral surface that forms a circular opening. In other words, stator core 261 is attached to bearing housing 207. However, this is not limitative, and stator core 261 may also be fixed to bearing housing 207 by using an adhesive in addition.

[0029] The rotor section 270 is configured by a rotor yoke 271 having a hollow cylindrical shape and made of a soft magnetic material, an annular magnet 272 arranged on the inner peripheral surface of the rotor yoke 271, and a shaft 277 arranged coaxially with the rotor yoke 271 and the magnet 272 and coupled to the hub 211 (described later) via a bushing 273. Incidentally, the rotor yoke 271 may be configured without using the bushing 273.

[0030] The inner peripheral edge of rotor yoke 271 is integrally fixed to the outer peripheral edge of bushing 273 by caulking. Shaft 277 is press-fitted into bushing 273. Rotor yoke 271, magnet 272, and shaft 277 are integrated via hub 211, and shaft 277 is integrated with hub 211 via bushing 273. In other words, impeller 210 is attached integrally with rotor yoke 271 of rotor section 270.

[0031] Impeller 210 includes hub 211 having a cup shape with a substantially inverted U-shaped cross section and a bottom, and a plurality of blades 212 provided along the circumferential direction on the outer circumferential surface of hub 211. Hub 211 and the plurality of blades 212 are integrally formed by injection molding of synthetic resin (for example, polybutylene terephthalate resin (containing glass fiber)).

[0032] Hub 211 of impeller 210 is integrally bonded with an adhesive to the outer peripheral surface of the upper side (direction of arrow a) of rotor yoke 271, which has a hollow cylindrical shape. However, this is not limitative, and rotor yoke 271 may be inserted into hub 211, and the inner peripheral surface of hub 211 and the outer peripheral surface of rotor yoke 271 may be integrally formed. In other words, hub 211 and rotor yoke 271 are integrated.

[0033] The plurality of blades 212 all have the same shape and are arranged at equal intervals in the circumferential direction of the hub 211. Therefore, the rotor section 270 functions as a rotating body, being integrated with the blades 212 by the hub 211 which is attached integrally with the rotor yoke 271. Therefore, when the rotor yoke 271 rotates around the shaft 277 due to the electromagnetic interaction between the stator section 260 and the rotor section 270, the impeller 210 rotates together with the rotor yoke 271, thereby forming an outer rotor type motor.

[0034] Hub 211 also covers the upper end (in the direction of arrow a) of shaft 277 to prevent foreign matter from entering from the outside. Incidentally, a coil spring 223 for applying a preload to bearing 221 is interposed between hub 211 of impeller 210 and bearing 221 fitted to the upper side in the direction of axis X (in the direction of arrow a).

[0035] The lower casing 300 has a cylindrical shape that is roughly square in plan view, and has an exhaust port 301 inside a side wall 304 that forms the square, for discharging air from the lower side in the axial X direction (the direction of arrow b). The lower casing 300 houses two circuit boards 400 and 500 for driving and controlling the motor 250 housed in the upper casing 200.

[0036] Like the upper casing 200, the lower casing 300 has four upper flange portions 302 at the upper corners (in the direction of arrow a) and four lower flange portions 303 at the lower corners (in the direction of arrow b).

[0037] Upper flange portion 302 and lower flange portion 303 are provided with through holes for inserting bolts (not shown) for attaching to a predetermined device or housing. Lower casing 300 is also integrally formed by injection molding of synthetic resin (for example, polybutylene terephthalate resin (containing glass fiber)).

[0038] In practice, the upper casing 200 and the lower casing 300 are formed separately, and then the through-holes in the lower flange portion 203 of the upper casing 200 and the through-holes in the upper flange portion 302 of the lower casing 300 are arranged opposite each other and brought into contact with each other, and then the casings are joined together with fasteners such as bolts via these through-holes. In this way, the casing 150 is formed, consisting of the upper casing 200 and the lower casing 300. However, the casing 150 may also be formed by integral molding.

[0039] 4, in lower casing 300, in order to form the through-holes in upper flange portion 302 and lower flange portion 303, thick portions 306 that are thicker than side wall 304 are formed around these through-holes. Thick portions 306 are part of side wall 304 and are formed between the through-holes and side wall 304.

[0040] A groove (hereinafter referred to as a "board insertion groove") 308 capable of holding the circuit board 400, 500 inserted therein is formed in the thick portion 306 of the side wall 304. The board insertion groove 308 is formed parallel to the axis X near the corner of the lower casing 300 so as to extend from the upper flange portion 302 to the lower flange portion 303.

[0041] Board insertion groove 308 is a rectangular recess that matches the shape of the end of circuit board 400, 500, has a predetermined depth, and extends in the vertical direction (direction of arrow ab) along axis X. The multiple board insertion grooves 308 are arranged so that those on diagonal lines of lower casing 300 face each other, and two opposing board insertion grooves 308 can hold circuit boards 400, 500.

[0042] The substrate insertion groove 308 is formed by injection molding a protruding wall 307 that protrudes toward the axis X from the thick portion 306 that is thicker than the side wall 304. Although the substrate insertion groove 308 is formed in only one location near the through hole in the thick portion 306 of the side wall 304, two locations may be formed in the thick portion 306 on both sides of the through hole.

[0043] Incidentally, the side wall 304 of the lower casing 300 is a thin plate-like portion, but the thick portion 306 is formed therein to prevent a decrease in strength due to the thin plate.

[0044] 5 and 6, circuit boards 400 and 500 have the same size and shape. Circuit boards 400 and 500 are printed wiring boards formed in a rectangular shape in a plan view and having multiple wiring layers on which various electronic components 411 and 511 that constitute a motor drive control circuit (not shown) that rotates and drives motor 250 are mounted. However, the present invention is not limited to this, and circuit boards 400 and 500 may also be single-layer printed wiring boards.

[0045] The motor drive control circuit is a circuit for controlling the rotation of the motor 250. The motor drive control circuit is realized by mounting various electronic components 411, 511 on circuit boards 400, 500 and electrically connecting them to the motor 250. The motor drive control circuit includes, for example, a control circuit that generates a control signal for controlling the rotation of the motor 250, and an inverter circuit that drives the motor 250 based on the control signal.

[0046] Circuit board 400 has a slit 404 cut out in the center of the rectangular lengthwise direction (arrow ab direction) from the bottom (arrow b direction) to the top (arrow a direction) to half its height. This allows wiring to be connected in the area where the slit is not formed, ensuring sufficient wiring connecting the left and right boards when the slit is centered, compared to a board with a slit that is half its height or more. The width of slit 404 is the same as or slightly larger than the board width of circuit board 500.

[0047] Similarly, a slit 504 is formed in the center of the rectangular longitudinal direction of circuit board 500, cutting it from the upper side (arrow a direction) to the lower side (arrow b direction) in the vertical direction (arrow ab direction) to half its height. The width of slit 504 is the same as or slightly larger than the board width of circuit board 400.

[0048] The slits 404 of the circuit board 400 and the slits 504 of the circuit board 500 slide against each other and engage with each other, thereby combining and joining the two boards together. In this case, the slits 404 of the circuit board 400 are half the length in the vertical direction (the direction of the arrow ab), and the slits 504 of the circuit board 500 are also half the length in the vertical direction (the direction of the arrow ab). Therefore, the circuit boards 400 and 500 have an excellent balance of strength when combined, and the reduction in the board mounting area due to the presence of the slits is kept to a minimum.

[0049] The circuit board 400 has rectangular flat pads 413 to 415, which are surfaces for soldering. The flat pad 413 is formed by a pad 413a on one side and a pad 413b on the other side, which are formed to straddle the slit 404 in the longitudinal direction.

[0050] Planar pad 414 is provided above (in the direction of arrow a) planar pads 413 (413a, 413b) and is formed only on one side of slit 404. Planar pad 415 is formed above (in the direction of arrow a) slit 404 and at the upper end of circuit board 400.

[0051] Two types of flat pads 413 (413a, 413b) and flat pad 414 are provided for one slit 404 because different signals flow through flat pad 413 and flat pad 414. Therefore, if the same signal flows through them, only one flat pad 413 (413a, 413b) or flat pad 414 may be used.

[0052] Furthermore, circuit board 400 has through holes 421a and 421b, which are formed around slit 404 and face each other with slit 404 in between, and which provide electrical continuity between layers. Through holes 421a and 421b are formed in a state where they overlap one side pad 413a and the other side pad 413b. Through holes 421a and 421b are recesses with semicircular cross sections that penetrate circuit board 400, and are therefore spatially connected to slit 404.

[0053] Furthermore, circuit board 400 has through hole 422, which is located above through hole 421a and is a recess with a semicircular cross section that communicates with slit 404. Through hole 422 is provided in a state where it overlaps flat pad 414 around slit 404, and has the same structure as through hole 421a. The inner surfaces of these through holes 421 (421a, 421b) and 422 are coated with a conductive material such as a copper film.

[0054] As described above, the circuit board 400 has planar pads 413 (413a, 413b) and 414 provided with through-holes 421 (421a, 421b) and 422, and a planar pad 415 without a through-hole. The presence or absence of a through-hole is determined by the magnitude of the current flowing through the planar pads 413 to 415, and when the current is large, providing the through-holes 421 and 422 can ensure high conductivity.

[0055] A plurality of electronic components 411 are attached to both longitudinal end portions of circuit board 400 in the vertical direction (the direction of arrow ab). This is because, when electronic components 411 are arranged in an exposed state in the air flow path created by blades 212 of impeller 210, the heat dissipation effect is improved.

[0056] Circuit board 500 has rectangular flat pads 513 to 518, which are surfaces for soldering. Flat pads 513 and 514 provided on the surface of circuit board 500 are formed to be aligned in the vertical direction (in the direction of arrow ab) below slit 504 (in the direction of arrow b). The surface of circuit board 500 is shown in FIG. 5(A), and the back side of circuit board 500 is shown in FIG. 5(B).

[0057] The flat pad 515 is formed around the slit 504 and includes a pad 515a on one side and a pad 515b on the other side formed to straddle the slit 504 in the longitudinal direction. Similarly, the flat pad 516 is also formed by a pad 516a on one side and a pad 516b on the other side formed to straddle the slit 504 in the longitudinal direction.

[0058] Planar pad 517 provided on the back surface of circuit board 500 is formed below slit 504 (in the direction of arrow b) at the lower end of circuit board 500. Planar pad 518 provided on the back surface of circuit board 500 is arranged at the upper end of circuit board 500 and is formed by one-side pad 518a and other-side pad 518b formed to straddle slit 504 in the longitudinal direction.

[0059] The circuit board 500 has through holes 521a and 521b, which are recesses with semicircular cross sections formed to face each other with a slit 504 in between, and which provide electrical continuity between layers of conductive patterns.

[0060] The through holes 521a and 521b are formed overlapping one side pad 516a and the other side pad 516b provided on the front surface of the circuit board 500, and one side pad 518a and the other side pad 518b provided on the back surface of the circuit board 500.

[0061] Through holes 521a and 521b are recesses with semicircular cross sections that penetrate circuit board 500, and are therefore spatially connected to slit 504. The inner surfaces of these through holes 521 (521a and 521b) are also coated with a conductive material such as a copper film.

[0062] In this way, the circuit board 500 also has planar pads 516 (516a, 516b) and 518 (518a, 518b) with through holes 521 (521a, 521b) provided therein, and planar pads 513, 514, 515 (515a, 515b), 517 with no through holes provided therein. In this case as well, the presence or absence of through holes is determined by the magnitude of the current flowing through the planar pads 513 to 518, and when the current is large, high conductivity can be ensured by providing the through holes 521 (521a, 521b).

[0063] In circuit board 500, a plurality of electronic components 511 are attached to both longitudinal end portions along the vertical direction (the direction of arrow ab). This is because, similar to circuit board 400, when electronic components 511 are arranged in a state where they are exposed in the air flow path created by blades 212 of impeller 210, the heat dissipation effect is improved.

[0064] The circuit boards 400 and 500 having such a configuration are arranged in a cross shape, and are combined by sliding and engaging with each other with the slits 404 and 504 facing each other. As a result, a cross-shaped integrated board 600 (FIG. 6) consisting of the circuit boards 400 and 500 is formed.

[0065] When circuit boards 400 and 500 are combined in this manner via slits 404 and 504, the inner circumferential surface of through-hole 421a of circuit board 400 faces planar pad 513 of circuit board 500 at close range. At the same time, the inner circumferential surface of through-hole 421b of circuit board 400 faces planar pad 517 of circuit board 500 at close range.

[0066] Similarly, the inner peripheral surface of through hole 422 of circuit board 400 and planar pad 514 of circuit board 500 face each other at close range. Furthermore, planar pad 415 of circuit board 400 and the inner peripheral surface of through hole 521b of circuit board 500 face each other at close range.

[0067] In this state, flat pad 413a of circuit board 400 and flat pad 513 of circuit board 500 are mechanically and electrically joined by soldering. At this time, solder also flows into through holes 421a, 421b, and 422 of circuit board 400 and through holes 521a and 521b of circuit board 500.

[0068] Thus, through holes 421 (412a, 421b) and 422 of circuit board 400 and planar pads 513 and 514 of circuit board 500 are mechanically and electrically joined by soldering. Also, through holes 521 (521a, 521b) of circuit board 500 and planar pad 415 of circuit board 400 are mechanically and electrically joined by soldering.

[0069] At this time, the through holes (412a, 421b), 422 and the planar pads 513, 514 of the circuit board 500 are connected by solder while facing each other at close range, which allows for cost reduction by minimizing the amount of solder that flows into the spaces of the semicircular cross-sectional through holes (412a, 421b), 422. In addition, because the solder fills the spaces of the semicircular cross-sectional through holes (412a, 421b), 422, the conductivity is further improved and the bonding strength is also improved.

[0070] In this way, the integrated substrate 600 is formed by combining the circuit board 400 and the circuit board 500 in a cross shape via the slits 404, 504 of each other, and the flat pads, which are the contact points of each other, are joined together with solder, and the flat pads are joined together via the through holes 421, 422, 521, so that the integrated substrate 600 is firmly connected mechanically and electrically.

[0071] This integrated substrate 600 is inserted while sliding into four substrate insertion grooves 308 formed in thick portion 306 of side wall 304 of lower casing 300, and is held in lower casing 300 (FIGS. 1 and 2). Note that integrated substrate 600 may also be inserted and held in substrate insertion grooves 308 of lower casing 300 by press-fitting.

[0072] As shown in Figure 7, the circuit boards 400, 500 of the integrated board 600 are arranged so as to overlap linearly with the longitudinally extending edge 206a of the multiple fixed wings 206 when held in the board insertion groove 308 of the lower casing 300.

[0073] When an even number of fixed wings 206 are provided at equal angular intervals, the integrated circuit board 600 is formed in a cross shape with 90-degree intervals, so that the circuit boards 400, 500 and the edge 206a of the fixed wings 206 can be arranged in a linear overlapping state.

[0074] In practice, when viewed from the bottom of the lower casing 300, the circuit boards 400, 500 of the integrated board 600 overlap linearly with the edge 206a of the fixed wing 206, but this is not limited to this, and as long as the circuit boards 400, 500 do not protrude beyond the edge 206a of the fixed wing 206 and do not overlap spatially with the fixed wing 206 (for example, between the fixed wing 2006 and the fixed wing 206), they do not necessarily have to overlap with the edge 206a.

[0075] As a result, the circuit boards 400 and 500 of the integrated board 600 do not become an obstacle that interferes with the flow of air rectified by the blades 212 of the impeller 210, and a decrease in efficiency of the fan device 100 can be suppressed.

[0076] The lower ends (in the direction of arrow b) and the lower half of the circuit boards 400 and 500 are coated with an insulating resin or the like. This coating makes the integrated board 600 less susceptible to static electricity.

[0077] In the above configuration, when an excitation current is applied to the coil 263 wound around the stator portion 260 of the motor 250 by the motor drive control circuit of the integrated substrate 600, the rotor yoke 271 rotates, and as the rotor yoke 271 rotates, the impeller 210 connected to the rotor yoke 271 also rotates, thereby functioning as a fan.

[0078] At this time, the air drawn in through intake port 201 of upper casing 200 on the upstream side by the rotation of impeller 210 becomes wind and is discharged from exhaust port 301 of lower casing 300 on the downstream side. Here, lower casing 300 accommodates circuit boards 400 and 500 of integrated board 600 in an inner space arranged in a cross shape, and electronic components 411 and 511 that generate a large amount of heat are exposed in the flow path, so that they are cooled efficiently.

[0079] In the fan device 100, the circuit boards 400 and 500 are arranged on the downstream side lower casing 300 so that the axis X, which is the rotation axis of the impeller 210, and the board surfaces are aligned.

[0080] As a result, in the fan device 100, two circuit boards 400, 500 are used to increase the fan output, nearly doubling the mounting area, but all of the electronic components 411, 511 on the circuit boards 400, 500 can be efficiently cooled without increasing the size of the casing 150 (upper casing 200 and lower casing 300).

[0081] In addition, in the fan device 100, the circuit boards 400 and 500 of the integrated substrate 600 are combined via the slits 404 and 504, and the planar pads are connected to each other with solder, so that the circuit boards 400 and 500 are firmly joined mechanically and electrically. Furthermore, in the fan device 100, the planar pads are joined to each other via the through holes 421, 422, and 521 of the circuit boards 400 and 500, so that the electrical conductivity is improved and the joining strength is further improved.

[0082] <Other embodiments> In the fan device 100 of the above-described embodiment, the cross-shaped circuit boards 400 and 500 of the integrated board 600 are held by the lower casing 300. However, the present invention is not limited to this, and as shown in FIGS. 8(A) to 8(E), multiple circuit boards may be held by the lower casing 300 along the axis X in various other combinations.

[0083] As shown in FIG. 8(A), an integrated board 1500 in which circuit boards 1100, 1200, and 1300 are combined in a triangular shape with their board surfaces arranged parallel to axis X may be held in board insertion groove 308 of lower casing 300. In this case, one end of circuit boards 1100 and 1200 is combined via slits provided in each board, and the other end of circuit boards 1100 and 1200 is combined with both ends of circuit board 1300 by adhesive bonding, fitting, or the like. In this integrated board 1500, electronic components are arranged on both longitudinal ends of circuit board 1300, similar to integrated board 600. However, since circuit boards 1100 and 1200 are arranged away from axis X along sidewall 304 and are positioned in the flow path of the airflow generated by impeller 210, electronic components may be arranged over the entire area of ​​the board. As a result, the integrated substrate 1500 can increase the mounting area of ​​electronic components to that of three substrates, and all electronic components that are placed in an exposed state within the air flow path generated by the impeller 210 are efficiently cooled.

[0084] 8(B), an integrated circuit board 2500 in which circuit boards 2100, 2200, 2300, and 2400 are combined in a substantially square shape with their board surfaces arranged parallel to axis X may be held in board insertion groove 308 of lower casing 300. In this case, four circuit boards 2100, 2200, 2300, and 2400 are combined together via slits provided in each board. In this integrated circuit board 2500, the mounting area for electronic components can be increased to that of four boards. Furthermore, since all four boards are arranged in the flow path of the airflow generated by impeller 210, electronic components may be arranged over the entire area of ​​the boards, and all electronic components are efficiently cooled by the airflow generated by impeller 210.

[0085] As shown in FIG. 8(C), an integrated circuit board 3500 may be held in the circuit board insertion groove 308 of the lower casing 300, in which circuit boards 3100 and 3200 are combined in a generally L-shape with their board surfaces parallel to the axis X. In this case, the circuit boards 3100 and 3200 are combined via slits provided in each circuit board. In this integrated circuit board 3500, the two circuit boards 3100 and 3200 are also arranged in the airflow path generated by the impeller 210, so electronic components may be arranged over the entire area of ​​the board. This not only increases the mounting area for electronic components in the integrated circuit board 3500 by two boards, but also efficiently cools all electronic components exposed in the airflow path generated by the impeller 210.

[0086] As shown in FIG. 8(D), an integrated circuit board 4500 may be held in the circuit board insertion groove 308 of the lower casing 300, in which circuit boards 4100, 4200, and 4300 are combined in a generally U-shape with their board surfaces arranged parallel to the axis X. In this case, the circuit boards 4100, 4200, and 4300 are combined with each other via slits provided therein. In this integrated circuit board 4500, the three circuit boards 4100, 4200, and 4300 are also arranged in the airflow path generated by the impeller 210, so electronic components may be arranged over the entire area of ​​the board. This not only increases the mounting area for electronic components in the integrated circuit board 4500 to that of three boards, but also efficiently cools all electronic components that are exposed to the airflow path generated by the impeller 210.

[0087] As shown in FIG. 8(E), an integrated board 5500 in which circuit boards 5100 and 5200 are combined in a generally V-shape and arranged parallel to each other along board surface axis X may be held in board insertion groove 308 of lower casing 300. In this case, one ends of circuit boards 5100 and 5200 are combined with each other by adhesive or fitting. In this integrated board 5500, electronic components are arranged on both longitudinal end portions of circuit board 5200, as in integrated board 600. However, since circuit board 5100 is arranged away from axis X along sidewall 304 and is itself arranged within the airflow path generated by impeller 210, electronic components may be arranged over the entire board. This allows integrated board 5500 to increase the mounting area for electronic components by two boards, and also allows all electronic components exposed within the airflow path generated by impeller 210 to be efficiently cooled.

[0088] 9(A) to 9(E), in fan device 7000, a lower casing 7300 having a new structure is attached integrally to upper casing 200 described above in the embodiment. That is, in fan device 7000, only the configuration of lower casing 7300 is different, and therefore, only lower casing 7300 will be described here.

[0089] Lower casing 7300 has a base 7301 and a lower flange 7303 as a frame, but does not have sidewalls 304 (FIG. 4) like those of lower casing 300. Instead, four circuit boards 7310, 7320, 7330, and 7340 serve as sidewalls instead. As shown in FIG. 9(D), circuit boards 7310 and 7330 are made of substantially T-shaped boards corresponding to the shape of lower casing 7300, and three engagement holes h1, which are through-holes that are rectangular in plan view, are provided on each side edge along the vertical direction (the direction of arrow ab). As shown in FIG. 9(E), circuit boards 7320 and 7340 are also made of substantially T-shaped boards of the same size and shape as circuit boards 7310 and 7330, and three engagement protrusions p1, which protrude in a rectangular shape in plan view, are provided on each side edge along the vertical direction (the direction of arrow ab).

[0090] Engagement holes h1 and engagement protrusions p1 of these circuit boards 7310, 7320, 7330, and 7340 are fitted together to form an integrated board 7350 that is square in plan view. Integrated board 7350 is fixed to lower casing 7300 by various methods such as adhesion or fitting, in place of a side wall. A joint member 7400 that serves as a spacer is interposed between integrated board 7350 and upper casing 200, and upper casing 200 and integrated board 7350 are connected via joint member 7400.

[0091] The copper wire of coil 263 extends downward (in the direction of arrow b) along fixed wing 206 of upper casing 200, and is then connected to integrated substrate 7350. This prevents excess copper wire from being generated in coil 263, thereby preventing problems such as wire breakage. Furthermore, all surfaces of integrated substrate 7350 facing outward are surface-treated by potting using resin or the like. This protects integrated substrate 7350 from stress and static electricity caused by external contact with circuit boards 7310, 7320, 7330, and 7340.

[0092] In the fan device 7000 configured in this manner, the bonding strength of the integrated substrate 7350 is improved by fitting the through hole h1 into the protrusion p1, and costs and weight are reduced by not having a side wall 304 like the lower casing 300.

[0093] Furthermore, those skilled in the art can appropriately modify the fan devices 100 and 7000 of the present invention and change the combination of various components in accordance with conventionally known knowledge. As long as such modifications still include the components of the present invention, they are of course included in the scope of the present invention. [Explanation of symbols]

[0094] 100, 7000... Fan device (axial fan motor), 150... Casing, 200... Upper casing, 300, 7300... Lower casing, 400... Casing, 201... Intake port, 202, 302... Upper flange portion, 203, 303... Lower flange portion, 204, 304... Side wall, 205... Motor base portion, 205, 205a... Base portion, 205b... Outer peripheral wall, 205c... Boss portion, 206... Fixed blade, 207... Bearing housing, 211... Hub, 212... Blade, 221, 222... Bearing, 223... Coil spring, 250... Motor, 260... Stator portion, 261... Stator core, 262... Insulator, 263... Coil, 270... Rotor portion, 271... Rotor yoke 272...magnet, 273...bush, 277...shaft, 301...exhaust port, 304...side wall, 306...thick portion, 307...protruding wall, 308...board insertion groove, 400, 500, 1100, 1200, 1300, 2100, 2200, 2300, 2400, 3100, 3200, 4100, 4200, 4300, 5100 ,5200,7310,7320,7330,7340...Circuit boards, 404,504...Slits, 411,511...Electronic components, 413~415, 517, 518...Flat pads, 421,422,521,600,1500,2500,3500,4500,5500,7350...Integrated boards, 7400...Joint members.

Claims

1. a hollow cylindrical casing having an intake port at one end in an axial direction and an exhaust port at the other end in the axial direction; an impeller having a plurality of blades housed in the casing; a motor housed in the casing for rotating the impeller; a plurality of circuit boards arranged along the axial direction on the exhaust port side of the casing; Equipped with At least one of the plurality of circuit boards that are combined by engaging with each other is provided with a slit, A through hole is formed around the slit. Axial fan motor.

2. Electronic components are mounted on the plurality of circuit boards, The electronic components are disposed on the circuit board in a state where they are exposed in the flow path formed by the impeller.

2. An axial fan motor according to claim 1.

3. The casing is formed by integrally joining an upper casing and a lower casing, The plurality of circuit boards are housed inside the lower casing.

2. An axial fan motor according to claim 1.

4. The plurality of circuit boards are held in board insertion grooves formed near the corners of the lower casing.

4. An axial flow fan motor according to claim 3.

5. The board insertion groove is formed in a thick portion of a flange formed at a corner of the lower casing.

5. An axial flow fan motor according to claim 4.

6. The plurality of circuit boards are held in the lower casing in a state where they are joined in a cross shape in a plan view.

6. An axial flow fan motor according to claim 5.

7. The plurality of circuit boards are held in the lower casing in a state where they are joined together in a triangular shape in a plan view.

6. An axial flow fan motor according to claim 5.

8. The plurality of circuit boards are held in the lower casing in a state where they are joined together in a rectangular shape in a plan view.

6. An axial flow fan motor according to claim 5.

9. The plurality of circuit boards are held in the lower casing in an L-shaped state in a plan view.

6. An axial flow fan motor according to claim 5.

10. The plurality of circuit boards are held in the lower casing in a U-shaped state in a plan view.

6. An axial flow fan motor according to claim 5.

11. The plurality of circuit boards are used as side walls of the lower casing.

4. An axial flow fan motor according to claim 3.

12. The plurality of circuit boards include a circuit board having an engagement hole formed therein; A circuit board is joined on which an engaging protrusion that engages with the engaging hole is formed.

12. An axial fan motor according to claim 11.

13. Electronic components are mounted on the plurality of circuit boards, the electronic component is disposed on the circuit board in a state where it is exposed in a flow path formed by the impeller, the electronic components are mounted only on the exposed surfaces of the plurality of circuit boards that are exposed to the flow path; The outer surface opposite to the exposed surface is coated.

13. An axial fan motor according to claim 12.

14. The circuit board has a surface treated by a predetermined potting process on the downstream side of the flow path.

14. An axial fan motor according to claim 13.

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