JP2006034055A - Stator, flat brushless fan motor equipped with that stator, and mobile apparatus mounting structure of that motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To cool a heat generating member by utilizing the space of a square corner effectively and arranging heat dissipation fins therein, providing the rotor of a brushless motor with an impeller and constituting an axial air gap microfan motor, thereby employing a mounting structure effective for a mobile apparatus. <P>SOLUTION: In a nonmetallic bracket 1 having a square plan view, a plurality of outermost parts 1aa are formed wider than other parts in each corner as a heat sink from where heat dissipation fins 1a rising integrally. The heat dissipation fin is provided with a fixing part 1ac having a step portion serving as a means for attaching a combination cover. Furthermore, a detent torque generating member 3 is arranged radially from the center, and a stator base 4 comprising an axial air gap air core coil 5, a driving circuit member D arranged at a position not superposing on the coil and supplying power to the coil, and a power supply electrode 4e arranged on a power supply terminal lead-out portion 1e is mounted on the inside of the heat dissipation fin. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a stator and a flat brushless fan motor having the same stator and a mobile device mounting structure of the motor, and an effective heat countermeasure for the mobile communication device using the same fan motor. About what to do.

In recent years, there has been a remarkable increase in the number of functions of mobile devices such as mobile phones, and the problem of heat generation in stored active electronic members has been newly highlighted. In particular, a case such as a CPU having a part that generates significant heat locally becomes hot during operation and becomes unpleasant to the human body.
In order to disperse this local heat generation, some proposals for storing an endothermic fixing element such as a ceramic sheet, a graphite sheet, and a heat pipe have also been adopted.
However, since it has become difficult to deal with the problem of heat generation due to recent multifunctionalization only by heat absorption by such a fixed element, a fan motor that forcibly circulates air has been studied.

Conventionally, a square axial fan has been frequently used to release heat generated in electronic devices such as personal computers to the outside. Such fan motors are known to have a large size of 80 mm square and 60 mm square, and there are those in which a heat sink is arranged outside the fan for thinning. However, the radial direction is sacrificed for this heat sink.
Also, fan motors with a size of 20 mm square or less have started to appear, but they are still too large to be mounted on a mobile device and used as a heat dissipation measure, and cannot cope with the recent trend toward miniaturization.
JP-A-9-107653

  In view of this, the present invention focuses on a square planar structure, effectively uses the space of the square corner, arranges heat radiation fins here, and provides an impeller on the rotor of the brushless motor. The heat generating member is intended to be cooled by forming a type micro fan motor and providing an effective mounting structure for a mobile device.

In order to solve the above-mentioned problem, as shown in claim 1, a planar view bracket made of a non-magnetic metal having a shaft support portion at its center has a plurality of heat radiation fins integrally raised at the corner, The heat sink is integrally provided with a power supply terminal lead-out portion, and the heat radiating fin is formed with a wide outermost portion, and a mounting portion that is a means for assembling the cover to be combined is provided with the wide heat radiating fin. A detent torque generating member is arranged in a radial direction from the center, an axial gap type air-core coil is disposed inside the radiating fin, a drive circuit member that is arranged at a position not overlapping with the coil, and supplies power to the coil, and the power feeding This can be achieved by a stator base having a power supply electrode placed on the terminal lead-out part and placed on the bracket.
In order to provide a flat brushless fan motor with such a stator, as shown in claim 2, the rotor housed rotatably in the stator is provided with a shaft support portion at the center and curved in an airfoil shape on the outer periphery. An impeller comprising a rear-facing fan is formed, and an axial air gap type magnet is arranged inside the impeller. The impeller is partly within the thickness of the rotor and the other part is the air-core armature coil. The cover is suspended in the axial direction so as to be within the thickness of the air-core armature coil on the outside of the drive circuit member, and the cover that covers the rotor is an air outflow / inlet hole so that the outer peripheral portion is in the middle of the fan This can be achieved by attaching the mounting leg portion formed in a hook shape on the side of the cover by fitting into the mounting portion of the radiation fin.
More specifically, as shown in claim 3, it is preferable that the impeller is integrally cut out from a rotor case provided with a magnet and is reinforced with a resin in an airfoil shape.
In order to mount these motors on a mobile device, the flat brushless fan motor according to claim 2 or 3 is mounted on a mobile communication device as shown in claims 4 and 5, and Whether the heat sink is attached to a heat generating electronic member via a graphite sheet on the member,
A flat brushless fan motor according to claim 2 or 3 is mounted on a mobile communication device, and a through hole is provided in a case of the mobile communication device, and outside air is guided from the through hole to an air inflow / outflow hole. This can be achieved if the heat transfer member extending in the radial direction from the heat sink comes into contact with the heat generating electronic member.

According to the first aspect of the invention, the dead space of the circular rotating body can be used because it is square, and the heat sink fin of the heat sink integrated with the bracket is arranged on the square corner, so that the structure is simplified and the The outside is formed wide and the mounting part, which is the means for assembling the cover to be combined, is provided on this wide heat radiation fin, so that the cover can be easily assembled, and the rear fan or the like to be combined is small but has good blowing efficiency. .
According to the invention of claim 2, since the airfoil-shaped rear-facing fan is used as the impeller shape, the air blowing efficiency is good, and the dead space of the rotating body is effectively used as the heat dissipating fin arrangement space. Good effective cooling is possible. Since the fan is partly within the thickness of the rotor, it can be configured without sacrificing the thickness, and the cover that appropriately controls the inflowing air can be easily removed by using the radiation fins. Can be firmly assembled.
According to the third aspect of the present invention, a sufficiently strong hardness can be obtained even if it is cut out from a thin rotor yoke.
According to the fourth and fifth aspects of the present invention, the heat generating active electronic member can be effectively cooled by taking in outside air, and the heat generating electronic member can be easily cooled by the heat transfer member such as a graphite sheet.

A square bracket made of lightweight non-magnetic metal with a shaft support at the center has a heat sink in which a plurality of heat radiation fins are integrally raised at the corner, and a power supply terminal lead-out portion is integrally provided on the side. The outermost portion of the heat dissipating fin is formed wide, and a mounting portion that is an assembly means of the cover to be combined is provided in the wide heat dissipating fin, and further, a detent torque generating member is arranged in the radial direction from the center, An axial gap type air-core coil inside the radiating fin, a drive circuit member that is arranged at a position that does not overlap with the coil, and that supplies power to the coil, and a power supply electrode placed on the power supply terminal lead-out part The stator, whose stator base is mounted on the bracket, has a shaft support at the center and a curved airfoil on the outer periphery. An impeller comprising a rearwardly facing fan is formed, and an axial gap type magnet is arranged inside the impeller. The impeller is partly within the thickness of the rotor and the other part is the air core armature coil. And the outside of the drive circuit member is suspended in the axial direction so as to span the thickness of the air-core armature coil, and the cover that covers this rotor is provided with an air inflow / outlet hole in the ceiling and formed in a side hook shape The assembled leg portions were assembled by fitting into the attachment portions of the heat radiating fins.
FIG. 1 is a plan view of one member constituting the stator of the flat brushless fan motor of the present invention.
FIG. 2 is a plan view of FIG. 1 configured as a stator. Example 1
FIG. 3 is a partially omitted plan view of a flat brushless fan motor including the stator of FIG. (Example 2)
4 is an enlarged sectional view taken along line AA of FIG. 3 of the motor.
FIG. 5 is an enlarged plan view of an essential part of a modified example of the impeller of the motor. Example 3
FIG. 6 is a schematic view of the flat brushless fan motor and the mobile communication device installed in the present invention. Example 4
FIG. 7 is a schematic view of another mounting example. (Example 5)

Hereinafter, the configuration of the present invention will be described based on the respective embodiments shown in the drawings.
In FIG. 1, a bracket 1 having a planar view, which is a member of a stator of a fixed axial type axial gap type coreless slotless type Hall sensor type brushless motor, also serves as a heat sink, and each corner has a plurality of radiating fins 1a. Is formed by integral molding through the air outflow groove a, and is formed by injection molding, for example, aluminum die-casting or the like, with a metal having good thermal conductivity.
Out of each radiating fin 1a, the outer side 1aa is wider than the others, and is provided with a fitting hole 1ac provided with a locking step portion 1ab into which a mounting leg portion of a cover described later is fitted.
Further, a shaft support portion 1 b into which the shaft 2 is press-fitted is raised at the center of the bracket 1. A weak magnetic stainless steel plate 3 having a thickness of 0.05 mm is embedded in the periphery of the shaft support portion to generate a detent torque at an opening angle of approximately 120 ° in the radial direction. Here, the detent torque generating member may be formed by printing a magnetic paint.
Further, a through-hole 1c that also serves as an air-core armature coil arrangement guide is formed facing each other, and also functions as an air flow together with the small hole 1d. A feeding electrode mounting portion 1e is led out integrally on one side surface. 1f is a recess provided to hold down a thickness direction of a later-described drive circuit member so that it bites into the bracket, and g is a protrusion arranged on the heat radiating fin for positioning and attachment strength when attaching a later-described cover. Is to secure.

In order to provide such a bracket as the stator S, it is as shown in FIG. 2 (see also FIG. 4). Inside the radiating fin 1a of the bracket 1, a stator base 4 made of a flexible substrate is guided by an inner diameter hole 5a formed at the position of the through hole 1c. 5a is used to adhere to each other and are connected in series to predetermined lands previously formed by printing on the stator base so as to have a single phase. The air-core armature coils 5 and 5 are set in accordance with the opening angle of the magnetic pole of the magnet combined with the effective conductor portion.
In a space where the air-core armature coils 5 and 5 are not arranged, one Hall sensor H and an IC driving circuit member D driven by the Hall sensor are arranged to face each other. In addition, you may use what a Hall sensor is incorporated in the drive circuit member. The inner diameter hole 4a of the stator base 4 is also used for cutting the plating line of the wiring pattern, and has a function of performing air circulation with another plating line cutting hole 4b coinciding with the position of the small hole 1d. The stator base 4 has a feeding electrode portion 4c led out at a side portion and is placed on the feeding electrode placement portion 1e.
In this stator, air is circulated through the through hole 1c formed in the bracket, the same inner diameter hole 4a of the stator base 4, and the inner diameter hole 5a of the coil.

Now, in order to make the above-described stator into a flat brushless fan motor, it is as shown in FIGS. In other words, the rotor R is attached to the center of the rotor case 6 made of a magnetic plate having a thickness of about 0.15 mm by fixing means such as caulking and welding, and the flat ring-shaped magnet 8 is bonded and fixed such as welding. Further, the impeller 6a composed of six rear-facing airfoil fans is integrally formed by cutting out the side surface of the rotor case 6. The impeller 6a is composed of a portion 6b within the thickness of the rotor and a hanging portion 6c that is partly inserted into the coil 5 through a gap outside the coil 5.
Such a rotor R is rotatably mounted on a shaft 2 fixed to the stator via a central oil-impregnated bearing 7 via three thrust washers W and encapsulated by a cover 9 made of nonmagnetic stainless steel. . The cover 9 has six rice-hole-shaped through holes 9a for taking air from the axial direction into the ceiling and letting it flow out from the air grooves g of the heat radiating fins 1a in the radial direction. The outer peripheral tip 6dd of the through hole 6d is positioned so as to be in the middle of the fan in terms of blowing efficiency.
In this way, the air introduced from the through hole 9a enters from the outer periphery of the rotor case 6 and the space of the through hole tip 6dd, is pushed out in the radial direction by the backward fan 6a, and is discharged to the side through the heat radiating fins 1a. .
The cover 9 is provided with a projection g of the heat radiating fin 1a and a mounting leg portion 9b fitted to the projection g and the through hole b and the fitting hole 1ac. The fitting legs 9b are press-fitted together, and then the protrusions are crushed, and the retainers 9ab that engage with the locking step portions 1ad of the fitting holes as shown in the partial explanatory view of the attachment legs as viewed from the side, are provided. Assembled with locking. In this way, the cover 9 has sufficient strength with the mounting legs and protrusions, but here the tip of the cover and the shaft is laser welded Y, so that it is satisfactory for securing impact resistance. Become. In addition, the cover 9 may be made to hang down a side periphery, and you may make it block | close a feed electrode part, and may block the unnecessary direction for the air outflow port of a radiation fin as needed.

The fan 6a of the impeller is thin, so that the strength can be ensured and a good airfoil shape can be obtained by molding the fan 6a with a resin J as shown in FIG. In this way, an airfoil-shaped backward-facing fan that is said to have the highest efficiency in ventilation can be obtained, and sufficient strength can be obtained even if the fan is thin, and a backflow between the ceiling portion of the cover 9 can be prevented by the resin. As a result, the ventilation efficiency is further increased.
Hereafter, what was demonstrated above by each member attaches | subjects the same code | symbol, and abbreviate | omits the description.

The flat brushless fan motor FM configured as described above has a thickness of the order of 2 mm as shown in FIG. 6, so that it is mounted on the CPU on the portable device side which is a heat generating active electronic member disposed on the main board K. It is mounted in a superimposed manner.
In this case, it is mounted directly or via a double-sided pressure-sensitive adhesive Z as in this example through a graphite sheet CS or a Peltier effect element having a high heat transfer effect. In the figure, B is a rechargeable battery and KA is a partition wall. In order to reduce the thickness, a part of the motor FM is accommodated in the through hole KAa of the partition wall.

FIG. 7 shows a case where a space for superimposing the flat brushless fan motor FM is not provided in the heat generating active electronic member CPU such as the central processing unit and the power amplifier in the lateral direction of the heat generating active electronic member CPU. A motor FM is mounted and connected by a heat transfer sheet CS. That is, a heat transfer sheet CS made of graphite is disposed on the upper surface of the heat-generating active electronic member CPU or power amplifier disposed on the main substrate K via a pressure-sensitive adhesive or heat conductive grease, The heat transfer sheet CS is extended in the lateral direction, and is configured to reach the bottom surface of the bracket 1 that also serves as the heat sink of the motor FM through a part of the noise prevention partition wall SK provided with the conductive material SKa at the tip. Is. The motor is attached to the cabinet KB1 of the device with an adhesive or the like through the transfer sheet CS. In the figure, SW is a switch board on which push buttons are arranged.
The cabinet KB2 on the upper surface of the motor is provided with a through-hole KBa for introducing outside air and a mesh sheet MS for preventing foreign matter from entering, and the outside air is guided to the through-hole formed in the cover of the motor as the motor rotates. In addition, outside air is taken in from the axial direction of the motor and is discharged in the radial direction through the heat radiating fins.
Therefore, the heat generated by the heat generating active electronic member CPU is cooled by the heat sink of the motor FM via the heat transfer sheet CS, and further efficiently cooled by the outside air by the heat radiating fins. Can suppress local heat generation and temperature rise.
Here, the position of the outside air introducing through hole KBa does not have to be particularly opposed to the motor, and a space in the cabinet may be used if outside air is guided.

As described above, the present invention can be applied to a portable small computer device such as a PDA in addition to a cellular phone.
The heat transfer sheet may be a metal sheet with good thermal conductivity such as copper foil.
Moreover, although the structure of this invention illustrated the thing of the axis | shaft fixed type | mold, it can employ | adopt also as a shaft rotation type.
The present invention can take various other embodiments without departing from the technical idea and characteristics thereof. Therefore, the above-described embodiment is merely an example and should not be interpreted in a limited manner. The technical scope of the present invention is indicated by the claims, and is not restricted by the text of the specification.

It is a top view of one member of the stator of the flat type brushless fan motor of this invention. It is the top view which comprised FIG. 1 to the stator. (Example 1) FIG. 3 is a partially omitted plan view of a flat brushless fan motor including the stator of FIG. 2. (Example 2) It is the AA cut | disconnection expanded sectional view of the motor of FIG. It is an enlarged principal part top view of the modification of the impeller of the motor. Example 3 It is the schematic mounted in the flat brushless fan motor and mobile communication apparatus of this invention. Example 4 It is the schematic of the other mounting example of the motor. (Example 5)

Explanation of symbols

1 Bracket as heat sink 1a Radiating fin
2 shaft 3 detent torque generating member 4 stator base 5 air-core armature coil 6 rotor case 6a rearward facing fan-shaped fan 7 bearing 8 magnet 9 cover 9a through hole 9b mounting leg J resin R rotor S stator FM flat brushless fan motor CPU Heat generation active electronic member CS Heat transfer sheet

Claims (5)

  A square bracket made of non-magnetic metal with a shaft support in the center is a heat sink with a plurality of heat-radiating fins integrally raised at the corner, and a power feed terminal lead-out part integrated on the side. The outermost portion of the heat dissipating fin is formed wider than the other, and a mounting portion having a locking step portion as an assembling means for the cover to be combined is provided on the wide heat dissipating fin, and further radially from the center. A detent torque generating member is disposed, an axial gap type air-core coil is disposed inside the heat radiating fin, a drive circuit member that is disposed at a position that does not overlap with the coil, and a power supply terminal derivation unit that supplies power to the coil A stator base having a power supply electrode placed on the bracket.   The rotor that is rotatably stored in the stator is provided with a shaft support at the center and an impeller made of a rearward fan that is curved in an airfoil shape on the outer periphery, and an axial gap type magnet is formed inside the impeller. The impeller is suspended in the axial direction so that part of the impeller is within the thickness of the rotor and the other part is within the thickness of the air-core armature coil outside the air-core armature coil and the drive circuit member. The cover covering the rotor is provided with an air inflow / outflow hole in the ceiling so that the outer peripheral part is in the middle of the fan, and a mounting leg part formed in a hook shape on the side of the cover is attached to the radiating fin. Flat type brushless fan motor assembled by fitting into the part.   The flat brushless fan motor according to claim 2, wherein the impeller comprising a rearward fan curved into an airfoil is cut out integrally from a rotor case provided with a magnet and is reinforced with resin on the airfoil.   A flat brushless fan motor according to claim 2 or 3 mounted on a mobile communication device, wherein the heat sink is attached to the heat generating electronic member via a graphite sheet. Body equipment mounting structure.   A flat brushless fan motor according to claim 2 or 3 is mounted on a mobile communication device, and a through hole is provided in a case of the mobile communication device, and outside air is guided from the through hole to an air inflow / outflow hole. A mobile device mounting structure of a flat brushless fan motor in which a heat transfer member extending in a radial direction from the heat sink comes into contact with a heat generating electronic member.

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