JPH10285872A - Fan motor with one end of shaft fixed to circuit board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a fan motor which is made much thinner than a conventional single-bearing-type fan motor and which can be miniaturized. SOLUTION: One end of a shaft 6 is forcibly fitted and fixed to a discoidal circuit board 15. A fan 7 is attached via a ball bearing 8 to the other end of the shaft 6, an IC 11 is attached to the shaft part on the rear side of the circuit board 15, and circuit components can be built in a venturi 12 easily. A space which is occupied by a fan motor including the circuit components can be reduced, and the fan motor can be miniaturized. The venturi is attached to the circuit board, and the circuit components are attached to other parts on the circuit board. As a result, the thickens of the fan motor can be made thin.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a fan motor having a structure in which one end of a shaft is fixed to a circuit board.

[0002]

2. Description of the Related Art The miniaturization of electronic devices such as portable terminals, personal computers, and communication devices has been progressing, and accordingly, there has been a demand for further miniaturization of fan motors for cooling electronic components and the like in the devices. Since the shape and size of the fan motor viewed from above are restricted by the performance of the fan motor, how to reduce the thickness is an issue of miniaturization. Further, if electronic components such as an IC attached to the fan motor can be accommodated in the fan motor, the space occupied by the fan motor including the electronic components can be reduced.

[0003]

FIG. 7 is a view showing an example of a conventional fan motor (Japanese Patent Laid-Open No. Hei 8-22639).
8). In this example, the thickness of the fan motor is reduced by supporting the blade 45 using one ball bearing 44. The inner ring of the ball bearing 44 is fixed to the small diameter shaft portion 47, and the cylindrical portion 48 of the blade 45 is
4 is fixed to the outer ring. The substrate 41 to which the leads of the coil 50 are connected is disposed below the cylindrical portion 48, and has a central portion having a hole through which the large-diameter shaft portion 46 passes. For this reason, the large-diameter shaft portion 46 hinders the mounting of an IC having a predetermined size or more on the substrate 41. Further, the arm portion 42 of the outer case 43 is provided below the substrate 41, and the fan motor is supported by the outer case 43 at this portion. Therefore, the thickness of the fan motor cannot be further reduced.

FIG. 8 is a diagram showing a single-bearing type fan motor proposed by the present inventor (Japanese Patent Laid-Open No. Hei 8-18225).
3). In this example, the thickness is reduced by supporting the fan 59 with one ball bearing 60. 7, the shaft 56 and the fan 59 are fixed, the shaft 56 is fixed to the inner ring of the ball bearing 60, and the outer ring is fixed to the housing 55. A triangular coil 58 is mounted on the fixed yoke 53 on the substrate 54, and a magnet 57 is attached to the fan 59 so as to face in the thrust direction to generate an attraction force in the thrust direction, so that the rotation of the one-bearing type fan motor is reduced. We are stabilizing. A stator support portion 52 integrated with a housing 55 is provided at a lower portion of the substrate 54 so that a motor frame 51
Holding the fan part.

In this example, the mechanism for stable rotation of the single-bearing fan motor is configured as described above, thereby achieving a further reduction in thickness as compared with FIG. However, also in this example, the space for mounting an IC or the like on the substrate has few surfaces on which electronic components such as an IC can be mounted because the housing 55 including the shaft is in the way. If the portion of the housing 55 including the shaft can be prevented from protruding to the back surface of the circuit board, electronic components can be mounted on this portion, and further larger electronic components can be attached, and the mounting area of the circuit board increases. Also, if the same mounting area is enough,
The external shape of the circuit board can be reduced. Further, since the motor has the stator support portion, it is not expected that the motor is made thinner. An object of the present invention is to provide a fan motor that can be further downsized.

[0006]

According to the present invention, there is provided a fan motor, wherein one end of a shaft is fixed to a circuit board, and a fan is attached to the other end via a ball bearing. Mount the coil on the board and attach the magnet to the fan,
A venturi is provided so as to surround the fan. In the above configuration, one end of the shaft is press-fitted into a through-hole provided in the circuit board, and the tip of the press-fitted one end is formed into a coaxial pattern provided around the through-hole on the back surface of the circuit board. By press-fitting, one end of the shaft can be fixed to the circuit board. Further, in the above configuration, the circuit board may be formed in a substantially disk shape, circuit components may be mounted on a back surface of the circuit board, and a peripheral edge of the circuit board may be supported by the venturi. Further, in the above configuration, the circuit board may be formed in a substantially disk shape, and an extension may be provided from a peripheral edge of the substantially disk, and a tip of the extension may be supported by a venturi. Further, in the above configuration, a venturi can be attached to the circuit board, and a circuit component can be mounted on the circuit board outside the venturi. In the above configuration, the shaft may be press-fitted into a yoke, a tip of the shaft may be inserted into a through hole of a circuit board, and the yoke and the shaft may be bonded and fixed to the circuit board.

[0007]

According to the above construction, the size can be further reduced. If the circuit board is formed in a substantially disk shape and circuit components are mounted on the back side, the size of the entire fan motor including the circuit components can be reduced. Further, if the circuit components are mounted on the circuit board outside the venturi, the thickness of the fan motor can be further reduced.

[0008]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a sectional view showing an embodiment of a fan motor in which one end of a shaft is fixed to a circuit board according to the present invention. FIG. 1A is a partial view focusing on the shaft, and FIG. It is. The shaft 1 is press-fitted and fixed at the center of a disc-shaped circuit board 3. The triangular coil 2 is mounted on the upper surface side of the circuit board 3 with the yoke 5 interposed therebetween. If there is room on the back side of the circuit board 3, a metal pattern 4 is provided, and the press-fitting strength can be increased by inserting the tip of the shaft 1 into this pattern 4.

FIGS. 2A and 2B show a first embodiment of a fan motor in which one end of a shaft according to the present invention is fixed to a circuit board. FIG. 2A is a sectional view, and FIG. It is the perspective view shown. After one end of the shaft 6 is press-fitted and fixed to the disc-shaped circuit board 15, the IC 11 is attached to the back side of the circuit board 15. An inner ring of a ball bearing 8 is fixed to the other end side of the shaft 6, a fan 7 is fixed to the outer ring, and a washer 9 for preventing removal is fitted. The triangular coil 10 is fixed on the upper surface of the circuit board 15 with the yoke 14 interposed therebetween, and the magnet 13 is attached to the facing fan 7.

The venturi 12 has an outer frame 12a forming a ventilation passage, and a cylindrical support 12 having an opening at the upper surface at the center.
and a connecting portion 12c supporting the cylindrical supporting portion 12b by the outer frame 12a and the outer frame 12a. The periphery of the circuit board 15 is fitted and supported on the upper part of the cylindrical support part 12b, and the IC 11 is accommodated in the cylindrical support part 12b. Since a space can be made on the back side of the circuit board 15, circuit components can be built in. The space occupied by the fan motor including circuit components can be reduced, and the overall size can be reduced.

FIGS. 3A and 3B show a second embodiment of a fan motor according to the present invention, in which one end of a shaft is fixed to a circuit board. FIG. 3A is a sectional view omitting a fan portion, and FIG. 3B is a venturi. It is the perspective view of (b) which omitted O. This embodiment is an example in which three support portions 16a are integrally provided around a disk-shaped circuit board 16. Circuit board 1 as in FIG.
The IC 17 is attached to the back surface of the support member 6 and one of the support portions 16a.
The lead wire 16b is led out from one of them. Support 16
The leading end of “a” is fitted and supported on the inner wall of the venturi 21, and the IC 17 is accommodated below the venturi 21.

FIGS. 4A and 4B are views showing a third embodiment of a fan motor in which one end of a shaft is fixed to a circuit board according to the present invention, wherein FIG. 4A is an exploded perspective view, and FIG. FIG. In this embodiment, a long groove 27e for ventilation is provided in a rectangular circuit board 27,
Between the long grooves 27e, there is a rib 27d for supporting a central circuit board portion surrounded by the long grooves 27e. One end of a shaft 22 is fixed to a central circuit board portion, and a triangular coil 23 is mounted. Around the long groove 27e, a hole 27c for attaching the venturi 30 is provided.
A venturi guide hole 27b for guiding the venturi 30 at the time of attachment is provided.

When the venturi 30 is mounted, the guide foot 30b is inserted into the venturi guide hole 27b so that the stop hole 30a of the venturi 30 and the hole 27c of the circuit board 27 are aligned and screwed. An IC 25 is mounted on a circuit board outside the venturi 30 and lead wires 26 are drawn out. With such an arrangement, the thickness of the fan motor can be reduced. Hall element 2
4 is installed on the rib 27d.

FIG. 5 is a diagram showing the positional relationship of the Hall element with respect to the triangular coil. A circuit pattern is formed on the upper surface side of the circuit board 27, and one rib 27d is formed as shown in FIG.
The triangular coil 23 is attached so that the angle up to the motor coking position. This secures the position where the Hall element 24 is installed, which can contribute to a reduction in the thickness of the fan motor. Further, the configuration shown in FIG. 4 can be easily applied not only to a lead wire but also to a connector.

FIG. 6 is a view showing another embodiment of the mounting structure of the shaft of the fan motor according to the present invention.
(A) is an exploded perspective view, (b) is an exploded sectional view, and (c) is an assembly view. The dimension 34 of the guide hole 32a of the disc-shaped circuit board 32 is larger than the outer diameter of the shaft 30. After the shaft 35 is press-fitted and fixed to the yoke 31, the tip of the shaft 35 is inserted into the guide hole 32a, and the yoke 31 The tip of the shaft is adhesively fixed to the circuit board 32. Since the guide hole 32a is not a press-fit fixed but a positioning hole, the IC 33
Can be attached to the circuit board 32 first. The assembly work is easier than mounting the circuit components on the back surface of the circuit board after fixing the shaft to the circuit board.

[0016]

As described above, according to the present invention, one end of a shaft is fixed to a circuit board, a fan is attached to the other end via a ball bearing, and a coil is mounted on the circuit board. A magnet is attached to the fan, and a venturi is provided so as to surround the fan. Therefore, the circuit components can be mounted on the back surface side of the circuit board, and the circuit components can be built in the fan motor. As a result, the installation space for the fan motor including the circuit components can be reduced, and the size of the fan motor can be reduced. In addition, if the circuit components are attached to the outside of the fan motor on the circuit board, the thickness can be further reduced as compared with the conventional fan motor, which can contribute to downsizing.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of a fan motor in which one end of a shaft is fixed to a circuit board according to the present invention, and is a partial view focusing on the shaft.

FIG. 2 is a view showing a first embodiment of a fan motor in which one end of a shaft is fixed to a circuit board according to the present invention;
FIG. 2A is a cross-sectional view, and FIG. 2B is a perspective view showing the vicinity of a support portion.

FIG. 3 is a diagram showing a second embodiment of a fan motor in which one end of a shaft is fixed to a circuit board according to the present invention;
FIG. 2A is a cross-sectional view, and FIG. 2B is a perspective view showing the vicinity of a support portion.

FIG. 4 is a view showing a third embodiment of a fan motor in which one end of a shaft is fixed to a circuit board according to the present invention;
(A) is an exploded perspective view, (b) is a sectional view after assembling a venturi.

FIG. 5 is a diagram showing a positional relationship of a Hall element with respect to a triangular coil.

6A and 6B are views showing another embodiment of the shaft mounting structure of the present invention, wherein FIG. 6A is an exploded perspective view, FIG. 6B is an exploded sectional view, and FIG.

FIG. 7 is a diagram illustrating an example of a conventional fan motor.

FIG. 8 is a diagram showing a single-bearing type fan motor proposed by the present inventors.

[Explanation of symbols]

 1, 6, 13, 18, 22, 35 ... shaft 2, 10, 19, 23 ... triangular coil 3, 16, 27, 32 ... circuit board 4 ... pattern 5, 14, 20 ... yoke 7 ... fan 8 ... ball bearing 9: Washer 11, 17, 25, 33 ... IC 12, 21, 30 ... Venturi 13 ... Magnet 15, 26 ... Lead wire 24 ... Hall element 31 ... Yoke 34 ... Hole dimensions

Claims (6)

[Claims] At least one end of a shaft is fixed to a circuit board, a fan is attached to the other end via a ball bearing, a coil is mounted on the circuit board, and a magnet is attached to the fan to surround the fan. A fan motor in which one end of a shaft is fixed to a circuit board as described above. 2. One end of the shaft is press-fitted into a through-hole provided in the circuit board, and the tip of the press-fitted one end is press-fitted into a hole of a pattern provided coaxially around the through-hole on the back surface of the circuit board. 2. The fan motor according to claim 1, wherein one end of the shaft is fixed to the circuit board. 3. The circuit board according to claim 1, wherein the circuit board is formed in a substantially disk shape, circuit components are mounted on a back surface of the circuit board, and a peripheral edge of the circuit board is supported by the venturi. A fan motor having one end of the shaft described above fixed to a circuit board. 4. The circuit board according to claim 1, wherein the circuit board is formed in a substantially disc shape, an extension is provided from a peripheral edge of the substantially disc, and a tip of the extension is supported by a venturi. A fan motor with one end of a shaft fixed to a circuit board. 5. The fan motor according to claim 1, wherein a venturi is mounted on the circuit board, and a circuit component is mounted on the circuit board outside the venturi. . 6. The system according to claim 1, wherein the shaft is press-fitted into a yoke, a tip of the shaft is inserted into a through hole of a circuit board, and the yoke and the shaft are bonded and fixed to the circuit board. A fan motor with one end of a shaft fixed to a circuit board.