JP2005023814A - Fan motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To implement the cooling which is suitable for the structure to be cooled with a micro-miniature size which is applicable for micro-miniature equipment such as a cellular phone in high cooling efficiency and the wider range. <P>SOLUTION: A fan motor is comprised of a motor 20 in which a rotary shaft is deduced in both sides of the axial direction; a pair of centrifugal fan impellers 30, 40 which are connected to the end of the rotary shafts, and rotate together with the rotary shafts; and a casing 10 covering the motor and both the fan impeller, and forming a suction port and an exhaust port. A pair of the fan impellers are set so that the axial length of each impeller blade is not less than the outside diameter of a circle composed of each impeller blade, respectively. In the casing, the suction port is formed at the opposed side to an opening which is formed at the opposite side of an end wall of both the fan impellers, and the exhaust port is formed opposed to the periphery of both the fan impellers. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
[Industrial application fields]
The present invention relates to a cooling fan motor used in electronic equipment and the like, and more particularly to a fan motor that requires high static pressure and high air volume.
[0002]
[Prior art]
A conventional centrifugal fan motor is configured using a flat fan impeller having a relatively short axial length (for example, see Patent Document 1).
[0003]
This conventional centrifugal fan motor will be described with reference to FIGS. FIG. 8 is a plan view of the centrifugal fan motor, and FIG. 9 is a longitudinal sectional view taken along the line X-O-Y-Z in FIG. The fan motor includes a motor unit 4 that generates a rotational driving force, an impeller unit 1 that generates an air flow, and a housing 6. This fan motor uses O in FIG. 8 as a rotation axis.
[0004]
The impeller portion 1 is disposed on the outer peripheral side of the motor portion 4 and is configured by a lower end wall 2 and a blade 3. The lower end wall 2 is an annular plate member disposed around the lower part in the axial direction of the motor unit 4, and the plane is directed in the axial direction. The lower end of the wing 3 is fixed to the outer peripheral side portion of the lower end wall 2. The wing 3 has a so-called cantilever structure that is supported only by the lower end wall 2. As the motor unit 4 rotates in the forward direction, the blade 3 generates an airflow in the direction of arrow B. An intake flow is generated in the direction of arrow A from the intake port 8 while being drawn into the air flow, and an exhaust flow is generated in the direction of arrow C while being pushed out by the air flow B. When the outer radius of the blade 3 is r and the length in the axial direction is h, the shape of the impeller portion 1 of the centrifugal fan used for cooling a conventional electronic device or the like has the blade radius r as its length h. There was a tendency to increase. This is because the purpose is to save space in the axial direction, but also to improve the air volume and static pressure of the exhaust flow B by improving the rotational peripheral speed of the blade 3. Therefore, in a conventional centrifugal fan motor having a cantilever impeller for cooling applications such as electronic equipment directly related to the present invention, the impeller has a thin shape having a relationship of r> h.
[0005]
[Patent Document 1]
JP 2003-031093 A
[Problems to be solved by the invention]
In such a conventional centrifugal fan motor, since the intake air flow A shown in FIG. 9 pushes down the air flow B, the air flow B collides with the lower end wall 2 and a large wind loss occurs between the wall surfaces. This is because, considering the wind speed distribution on the rotating shaft of the impeller portion 1, it is expected that the wind speed of the air flow in the impeller to be sucked is maximized on the upper surface of the impeller lower end wall 2. Due to this windage loss, the flow rate of the fan decreased, and only a cooling efficiency lower than that inherent in the performance of the fan motor could be realized.
[0006]
On the other hand, in recent years, electronic devices have been miniaturized and ported, and devices such as mobile phones and mobile personal computers have been required to be further downsized. On the other hand, the degree of integration of electronic circuits has been improved and the processing speed has increased, so the total heat generation of LSI chips and built-in electronic circuit sections is increasing, and a fan motor with a smaller size and higher cooling efficiency is required. It was done.
[0007]
An object of the present invention is to provide an ultra-small and high cooling efficiency fan motor that can be applied to ultra-small devices such as mobile phones. Another object of the present invention is to provide a fan motor that achieves a maximum cooling effect with a minimum inlet area. Still another object of the present invention is to provide a fan motor capable of realizing cooling suitable for a structure to be cooled in a wider range.
[0008]
[Means for Solving the Problems]
In order to achieve such an object, a fan motor according to the present invention includes a rotation drive unit in which rotation shafts are led out on both sides in the axial direction, and a pair of centrifugal types that are connected to the ends of both rotation shafts and rotate together with the rotation shafts. The fan impeller and a casing that covers the rotation drive unit and both fan impellers and has an air inlet and an air outlet are formed. Each of the pair of fan impellers has a disk-shaped end wall portion to which the rotation shaft is connected, and a circumferentially extending centering on the axis of the rotation shaft extending in the axial direction so as to rise from the outer peripheral portion of the end wall portion. And the length of each impeller blade in the axial direction is set to be greater than or equal to the outer diameter of a circle formed by each impeller blade. Further, the casing is formed with an intake port facing an opening formed on the opposite side to the end wall portions of both fan impellers, and an exhaust port is formed facing the outer peripheral portion of both fan impellers. ing.
[0009]
When the rotation drive unit operates, a pair of fan impellers positioned on both sides in the axial direction rotate, and air is sucked into the inside of the two fan impellers through the respective opening portions of the two fan impellers. The air pushed from the impeller blades in the outer peripheral direction is discharged from two exhaust ports of the casing.
[0010]
Inside the fan impeller, an axial airflow that flows from the opening toward the end wall is generated, but since the axial length of the impeller blade is set to be greater than or equal to the outer diameter of the outer periphery of the impeller blade, the impeller Most of the airflow inside the wings flows toward the outer side in the circumferential direction before reaching the end wall portion, and the airflow velocity is sufficiently lowered on the wall surface of the end wall portion. For this reason, compared with the conventional centrifugal fan motor, the windage loss at the wall surface of the end wall portion is reduced, and the cooling efficiency is improved.
[0011]
Here, in the fan motor described above, the rotational drive unit can be configured using a set of magnetic circuit units including a stator drive coil supported by the fixed unit and a rotor magnet provided on the rotor. . In this case, the rotating shaft that rotates integrally with the rotor needs to be rotatably supported by the fixed portion so as to penetrate the rotation driving portion, and both axial ends of the rotating shaft are supported by the rotation driving portion. The fan impeller is connected to each of them.
[0012]
Alternatively, the rotation drive unit includes two sets of magnetic circuit units each including a stator having a drive coil supported by a fixed unit and a rotor magnet provided on the rotor, and a rotation shaft that rotates integrally with each rotor. May be rotatably supported by the fixed portion, and the end of each rotating shaft may be led out from the rotation driving portion to connect the fan impeller.
[0013]
In particular, the rotational drive unit is composed of a pair of motor units having the same shape, and both motor units are integrally connected with their base ends back to back, and the rotation shaft ends on the respective distal end sides of both motor units It can also be set as the structure which connects a fan impeller to a part.
[0014]
Further, in the fan motor described above, the casing is formed in an elongated cylindrical shape, the intake ports are formed at both ends in the longitudinal direction, and the two exhaust ports respectively opposed to the pair of fan impellers are axially arranged on the side surfaces of the casing. At the same rotational position. The two exhaust ports formed in the casing can be arranged at different rotational positions with respect to the axial center on the side surface of the casing, depending on the cooling layout of the device such as an electronic device to which the fan motor is applied. For example, they can be arranged at positions that are in a rotation target relationship of 90 degrees with respect to the shaft center or at positions that are in a rotation target relationship of 180 degrees with respect to the shaft center. It becomes possible.
[0015]
The above-described fan impeller is preferably formed by resin molding, and can be formed of, for example, a liquid crystal polymer, a carbon fiber reinforced liquid crystal polymer, a glass fiber reinforced liquid crystal polymer, a carbon fiber, and a glass fiber reinforced liquid crystal polymer. Needless to say, the present invention is not limited to this, and a part or the whole thereof can be constituted by soft iron, stainless steel, aluminum, or ceramic.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of a centrifugal fan motor according to the present invention will be described with reference to the drawings. 1 to 4 show a first embodiment, FIG. 1 is a schematic front view of a fan motor, FIG. 2 is a cut front view, FIG. 3 is a side view, and FIG. 4 is a schematic perspective view for explaining airflow by the fan motor. It is. 1 and 2 is the direction of the rotational axis of the centrifugal fan motor. In the following description, "upper side", "lower side", etc. are defined according to FIGS. 1 and 2, but this is for convenience of description. Therefore, the actual mounting posture of the fan motor is not limited.
[0017]
As shown in FIG. 1, the fan motor includes a cylindrical casing 10 that is elongated in the left-right direction, and a motor unit 20 that serves as a rotational drive unit that is fixed at the center of the casing 10 with a rotation axis disposed in the left-right direction. , And a pair of centrifugal fan impellers 30 and 40 which are arranged on the left and right sides of the motor unit 20 and are driven to rotate by the motor unit 20 respectively. The rotational axis of each of the fan impellers 30 and 40 coincides with the rotational axis of the motor unit 20.
[0018]
As shown in FIG. 4, the casing 10 includes an outer peripheral surface of the housing 21 of the motor unit 20, and is configured by connecting the bottomed cylindrical impeller covers 11 and 12 to the housing 21, and both the impeller covers 11 and 12. Are formed on the bottom surface of the casing 10, that is, on the left and right end surfaces of the casing 10, respectively, and the horizontally long exhaust ports 15, 16 are formed on a part of the peripheral surface of each of the impeller covers 11, 12. ing. Both the exhaust ports 15 and 16 are arranged so as to face in the same circumferential direction of the casing 21 (specifically, forward).
[0019]
The motor unit 20 as a rotational drive unit is a brushless DC motor. As shown in FIG. 2, the motor unit 20 has a housing 21 provided with a peripheral wall part 21b on the outer periphery of the base part 21a, and is supported and fixed to the base part 21a of the housing 21. The annular stator 22, a sleeve bearing (slide bearing) 23 that is long in the left-right direction and fixed to the center portion of the base portion 21 a and the inside of the stator 22, and is inserted into the sleeve bearing 23 to be rotatably supported. The rotary shaft 24 is connected to the rotary shaft 24 so as to be integrally rotatable, and a rotor yoke 26 is provided on the inner side of the rotor rotor 26. The rotor yoke 26 is formed in a cup shape by, for example, pressing a magnetic metal plate, and the center portion of the top plate is connected to the rotary shaft by press fitting or the like. Both left and right ends (both ends in the axial direction) of the rotating shaft 24 are led out from the motor unit 20 to both sides in the axial direction.
[0020]
The stator 22 is configured by laminating a plurality of press-formed magnetic steel plates (laminations) in the axial direction, and has, for example, four magnetic pole teeth in the circumferential direction, and each of the magnetic pole teeth has multiple phases (for example, two phases). ) Coil is wound. The coil termination of the multiphase coil is electrically connected to the terminal of the flexible circuit board pasted on the back surface (left surface) through the disk portion 21a by soldering or the like, and the lead terminal of the flexible circuit board is the housing 21. It is pulled out more. In this embodiment, although not shown, a driver circuit is provided outside the fan motor, and lead terminals of the flexible circuit board are connected to the driver circuit. When the driver circuit is operated to energize the coil of the stator 22 to excite it, a rotational force acts on the rotor due to the mutual electromagnetic action of the stator 22 and the rotor magnet 25, and the rotor 22 rotates with the rotating shaft 24.
[0021]
Inside the impeller covers 11 and 12 of the casing 10 are bottomed cylindrical fan impellers 30 and 40, respectively. As shown in FIGS. 2 and 3, the fan impellers 30 and 40 extend in the axial direction so as to rise from the disk-shaped end wall portions 31 and 41 and the outer peripheral portions of the end wall portions 31 and 41, respectively. A plurality of impeller blades 32, 42 arranged at equal intervals in the circumferential direction on a circumference centered on the axis of the wall portions 31, 41 are configured, and the tip portions of the impeller blades 32, 42 are annular. It is connected by connecting portions 33 and 43, and the strength at the tip portion is ensured. Then, by connecting the end wall portions 31 and 41 to the both ends of the rotating shaft 24 in the motor unit 20 at their axial centers, both fan impellers 30 and 40 are cantilevered by the rotating shaft 24, and the rotating shaft 24 can be rotated together. Both fan impellers 30 and 40 have outer diameters R1 and R2 (for example, R1 = R2) of circles in which axial lengths H1 and H2 of impeller blades 32 and 42 capable of generating an exhaust flow are constituted by the impeller blades 32 and 42, respectively. It is set above.
[0022]
The pair of fan impellers 30, 40 is set so that the inclination of the impeller blades 32, 42 with respect to the rotational axis is symmetrical with respect to the motor unit 20, and both fan impellers 30, 40 are in the same direction together with the rotational shaft 24. The airflow is generated radially outward, that is, in the centrifugal direction. That is, when both fan impellers 30 and 40 rotate together with the rotary shaft 24 in a certain direction, air flows from the inner peripheral side to the outer peripheral side by the action of the respective impeller blades 32 and 42, and accordingly the fan impeller 30. , 40 generate air currents that are sucked into the openings 34 and 44 opposite to the end wall portions 31 and 41, and function as centrifugal fans.
[0023]
The intake ports 13 and 14 on both end faces of the casing 10 described above are coaxially close to and opposed to the openings 34 and 44 of the fan impellers 30 and 40, respectively. Further, the inner peripheral surfaces of the impeller covers 11 and 12 of the casing 10 move the air flowing in the centrifugal direction from the impeller blades 32 and 42 in the rotational direction of the fan impellers 30 and 40, respectively. The curved surface is guided to the exhaust ports 15 and 16. Accordingly, the airflows generated by the rotation of the fan impellers 30 and 40 respectively draw external air from the intake ports 13 and 14 of the casing 10 through the openings 34 and 44 into the fan impellers 30 and 40, respectively, and then the fan impellers. The air is discharged in the direction of the outer periphery 30 and 40, and further flows through the inner peripheral surfaces of the impeller covers 11 and 12 to the front surface from the exhaust ports 15 and 16, respectively.
[0024]
In the fan motor configured as described above, for example, a space for air intake is secured on both sides of the casing 10 of the fan motor inside the portable electronic device or small device, and the casing 10 It accommodates in the arrangement | positioning that a to-be-cooled body is located in the position of the front surface. Then, by driving the motor unit 20 of the fan motor, air inside the apparatus and inside the apparatus is taken in from the intake ports 13 and 14 on both sides of the casing 10 and blown out from the exhaust ports 15 and 16 on the front surface of the casing 10. An air flow is generated, and this air flow is guided to the object to be cooled and forcedly cooled.
[0025]
In the fan motor according to the present invention, the outer diameters R1 and R2 of the impeller blades 32 and 42 of the fan impellers 30 and 40 are different from those of the conventional centrifugal fan motor shown in FIG. The axial lengths of the impeller blades 32 and 42 that can generate the exhaust flow (more specifically, the opening side surfaces of the end wall portions 31 and 41 and the end wall portion side surfaces of the annular connecting portions 34 and 44) A length in the axial direction of the portion between the two is longer than H1 and H2 (for example, H1 = H2). In addition, the fan motor according to the present invention makes it possible to cool a portable electronic device or a small device with high static pressure with high efficiency, and is characterized by R1, R2 <20 mm.
[0026]
When the axial lengths H1 and H2 of the impeller blades 32 and 42 are made longer than the outer diameters R1 and R2 of the impeller blades 32 and 42, the intake air flow generated by the airflow in the rotating outer circumferential direction by the impeller blades 32 and 42 is It is possible to smoothly switch to the air flow in the rotational outer periphery direction before reaching the end wall portions 31 and 41 from the openings 34 and 44, and to reduce the wind speed on the surfaces of the end wall portions 31 and 41, and thus loss. It is possible to generate a high-efficiency air flow with a small size. In addition, since the fan impellers 30 and 40 disposed on both sides of the motor unit 21 are driven simultaneously by driving the motor unit 21 and an air flow is generated in each of them, the air can be blown to the object to be cooled. It will be able to cope with internal cooling in small-sized equipment and devices with high density mounting.
[0027]
In particular, as shown in FIG. 4, by the operation of both fan impellers 30 and 40, the air sucked in from the intake ports 13 and 14 on both sides of the casing 10 as indicated by arrows A1 and A2 is sucked into the casing 10, and the casing The two airflows blown out as indicated by the arrows C1 and C2 from the exhaust ports 15 and 16 on the front surface of 10 are formed. In such a configuration, since intake and exhaust are performed on substantially the same plane, it is suitable for forming an air flow inside a flat and thin electronic device such as a notebook computer.
[0028]
As described above, the fan motor according to the present invention has been developed especially for cooling portable electronic devices and small devices, and in order to obtain higher cooling efficiency, the fan shape is smaller and the speed is higher. It is desirable to use at the number of rotations. It is usually recommended to use in the range of 20000 rpm to 30000 rpm, but this must satisfy the requirements such as motor performance, balance of power consumption vs. cooling performance, realization of vibration loss and noise amount below a certain level, etc. Because. If a high-performance motor that sufficiently satisfies these conditions can be realized, a fan motor with higher static pressure and higher cooling efficiency can be realized by operating at a rotational speed of 30000 rpm or more, and further exceeding 40000 rpm.
[0029]
On the other hand, the impeller blade diameters R1 and R2 in this case are preferably 20 mm or less in practice. This is because the thickness of the portable electronic device is usually around 20 mm and needs to be built in the portable electronic device. In consideration of a mobile phone or the like, the diameter of the impeller blade is preferably 10 mm or less. Of course, the characteristics of the fan motor of the present invention can be realized even with impeller blades having a diameter of 15 mm or 20 mm larger than this, but in order to suppress the loss due to the collision of the intake flow with the end wall portions 31 and 41. Requires a high speed rotation of 5000 rpm or higher, preferably 10,000 rpm or higher. When the radius of the fan is increased, the motor is burdened. Although it can be realized by using a high-performance motor, it is desirable to use impeller blades of R1, R2 <20 mm with less motor load in practice. More preferably, R1, R2 <10 mm.
[0030]
The fan impellers 30 and 40 are partially or entirely made of liquid crystal polymer, carbon fiber reinforced liquid crystal polymer, glass fiber reinforced liquid crystal polymer, carbon fiber and glass fiber reinforced liquid crystal polymer, soft iron, stainless steel, aluminum, or ceramic. Preferably it is. As a result, the fan impellers 30 and 40 can be reduced in weight and size while ensuring sufficient rigidity.
[0031]
In addition, in the above-mentioned embodiment, although it was set as the structure which blows off two airflows created with a fan motor in the same direction, it is not restricted to this, The other ventilation direction is set changing an angle with respect to one ventilation direction. It is possible. That is, as shown in FIG. 4, an angle difference of 90 degrees is formed with respect to the balloon indicated by the arrow C2 to set the balloon indicated by the arrow C1 ′, or an angle difference of 180 degrees is formed and the balloon indicated by the arrow C1 ″. This can be realized by, for example, rotating the impeller cover 11 on the left side of the casing 10 90 degrees and 180 degrees with respect to the right impeller cover 12 and connecting them, of course, 60 degrees, 30 degrees, etc. Other angle differences may be set.
[0032]
In this way, if an air flow can be formed simultaneously in two different directions with a single fan motor, an optimal cooling system can be selected according to the internal structure, layout, heat source shape, etc. of small equipment and devices with high-density mounting. It can be built.
[0033]
<Other embodiments>
Next, a second embodiment of the present invention will be described with reference to FIG. FIG. 5 shows a part of the fan motor with the rotation drive unit as the center, and the same reference numerals as those described in the first embodiment denote the same or corresponding parts.
[0034]
In the embodiment shown in FIG. 5, the rotor of the motor unit 20 as the rotation drive unit is integrally connected to the end wall portion 41 of the impeller fan 40 on one side. That is, an annular protrusion 45 for caulking is formed near the outer peripheral portion of the surface on the motor portion 20 side of the end wall portion 41 of the fan impeller 40, and the inner peripheral side is formed on the end portion on the fan impeller 40 side of the rotor yoke 26 formed of a cylindrical body. An annular end edge 27 is formed by bending the ring-shaped protrusion 27, the annular end edge 27 is fitted to the outer side of the annular protrusion 45, and then the annular protrusion 45 is plastically deformed in the outer circumferential direction and caulked to thereby form the rotor yoke 26. Are integrally coupled to the end wall portion 41. In this case, the end wall portion 41 constitutes a part of the rotor.
[0035]
According to the embodiment having such a configuration, the rotor of the motor unit 20 and the fan impeller 40 on one side can be integrated, and not only the function of blocking the airflow in the axial direction in the fan impeller 40 but also the motor unit. It also has a function as 20 wall surfaces. For this reason, the number of parts is reduced, the longitudinal dimension can be reduced as compared with the first embodiment, and the fan motor is downsized in the axial direction. Furthermore, the fan motor is reduced in weight.
[0036]
Next, a third embodiment of the present invention will be described with reference to FIG. In this embodiment, the rotation drive unit is composed of a pair of motor units 120A and 120B, and centrifugal fan impellers 130 and 140 are connected to the rotation shafts of the motor units 120A and 120B, respectively. The impellers 130 and 140 are configured to be rotatable, and both the motor parts 120A and 120B are integrally connected in a back-to-back state, and this is housed in a horizontally long cylindrical casing 110 to constitute a two-wing fan motor. is there.
[0037]
Each of the fan impellers 130 and 140 has an end wall portion on the side of the rotation drive portion and extends in the axial direction so as to rise from the outer peripheral portion of the end wall portion, as in the first and second embodiments. A plurality of impeller blades arranged on a circumference around the rotation axis is provided, and an opening is provided on the side opposite to the rotation drive unit. Both fan impellers 130 and 140 are cantilevered by connecting their end wall portions to the rotation shafts of the motor portions 120A and 120B.
[0038]
Air inlets are formed on both end surfaces of the casing 110 in the longitudinal direction, the openings of the fan impellers 130 and 140 are opposed to the air inlets, and external air is sucked from the air inlets by the rotation of the fan impellers 130 and 140. It is like that. Exhaust ports are formed on the peripheral side surface of the casing 110 so as to correspond to the fan impellers 130 and 140, respectively. Air blown outward in the circumferential direction from the impeller blades of the fan impellers 130 and 140 is formed inside the casing 110. The air is guided to the exhaust port through the peripheral surface, and blown to the outside from the exhaust port.
[0039]
In this case, the motor units 120A and 120B are configured to rotate their rotation shafts in opposite directions, and by arranging the motor units 120A and 120B back to back, the fan impellers 130 and 140 are consequently disposed. It can be rotated in the same direction. Of course, both motor parts 120A and 120B are configured to rotate their rotational axes in the same direction, and both motor parts 120A and 120B are arranged back to back and both fan impellers 130 and 140 are configured to rotate in opposite directions. In this case, by setting the inner surface shape of the casing 110 in accordance with the fan impellers 130 and 140, various air blows (C1, C1 ′, C1 ″ and C2) as described in FIG. 4 can be realized.
[0040]
Next, a fourth embodiment of the present invention will be described with reference to FIG. In this embodiment, as in the third embodiment, the rotation drive unit is configured by a pair of motor units 220A and 220B. The difference from the third embodiment is that the motor units 220A and 220B In addition, a pair of fan impellers 230 and 240 that are respectively rotated by the motor unit are integrally configured. In addition, the housings 221A and 221B of the motor units 220A and 220B and the impeller covers 211 and 212 respectively connected to the motor units 220A and 220B It is the point which comprised the casing.
[0041]
The motor parts 220A and 220B that are integrally connected in a back-to-back state are made of brushless DC motors, and are supported by housings 221A and 221B having a peripheral wall part on the outer periphery of the base part and the base parts of the housings 221A and 221B. Annular stators 222A and 222B that are fixed, sleeve bearings 223A and 223B that are fixed to the center of the base and the inside of the stators 222A and 222B, and that are long in the left-right direction. Rotating shafts 224A and 224B that are freely supported, and cylindrical yokes 226A that are connected so as to be integrally rotatable with the rotating shaft 24 and are mounted with cylindrical rotor magnets 225A and 225B so as to face the stators 222A and 222B. 226B. The base ends of the rotating shafts 224A and 224B are thrust supported by the housings 221A and 221B, respectively.
[0042]
On the other hand, the fan impellers 230 and 240 are respectively extended so as to stand up outward from the outer peripheral portions of the disk-like end wall portions 231 and 241 and the end wall portions 231 and 241 in the axial direction. A plurality of impeller blades 232 and 242 arranged on the circumference centered on the center at equal intervals in the circumferential direction, and cylindrical portions 235 extending inward in the axial direction on the outer peripheral portions of the end wall portions 231 and 241. 245 is integrally formed of, for example, resin.
[0043]
And the front-end | tip part of rotating shaft 224A, 224B of motor part 220A, 220B is connected with the center of fan impeller 230, 240, respectively, and it is a rotor via the yoke 226A, 226B to the internal peripheral surface of cylindrical part 235,245. Magnets 225A and 225B are mounted, whereby end wall portions 231 and 241 and cylindrical portions 235 and 245 also serve as a rotor holder, and motor portions 220A and 220B and fan impellers 230 and 240 are configured integrally. Become.
[0044]
Impeller covers 211 and 212 covering the outer peripheries of fan impellers 230 and 240 are connected to the peripheral wall portions of housings 221A and 221B, respectively, and the peripheral wall portions of housings 221A and 221B and impeller covers 211 and 212 constitute a fan motor casing 210. . The two impeller covers 211 and 212 are respectively formed with intake ports 213 and 214 located on both end surfaces of the casing 210, and these are close to and coaxially opposed to the openings 234 and 244 of the fan impellers 230 and 240, respectively. Further, the inner peripheral surfaces of the two impeller covers 211 and 212 of the casing 210 move the air flowing in the centrifugal direction from the impeller blades 232 and 242 in the rotational direction of the fan impellers 230 and 240, respectively. It is formed in the curved surface which guides to an exhaust port (not shown).
[0045]
Also in this embodiment, the rotation directions of the pair of motor parts 220A and 220B may be the same direction or different directions, and the exhaust ports formed in the impeller covers 211 and 212 may be directed in the same direction, or may be angularly different from each other. (90 degrees, 180 degrees) can also be provided. In particular, in the case of this embodiment, if the motor unit 220A, the fan impeller 230, the impeller cover 211, and the motor unit 220B, the fan impeller 240, the impeller cover 212 are each configured as a single-wing fan, both units are back to back. It is possible to obtain a two-blade fan motor by coupling to the above, and the manufacturing becomes simple.
[0046]
The embodiments of the present invention have been described above. However, the present invention is not limited to these embodiments, and various modifications can be made without departing from the gist of the present invention. For example, in the above embodiment, the fan impeller and the motor unit constituting the fan motor are arranged side by side in the axial direction, but the motor unit is arranged on the inner peripheral side of the impeller unit as in the prior art shown in FIG. It is good also as a structure (that is, both overlapped in the axial direction all or one part).
[0047]
Further, part or all of the inner peripheral corner portion on the upper end side in the rotation axis direction of the impeller blades may be chamfered with an arc shape or a curved shape approximating this. By applying an arc-shaped chamfer to the inner peripheral corner portion on the upper end side in the rotational axis direction of the impeller blade, the intake air flow into the impeller flows more smoothly and at the same time, unnecessary turbulence is suppressed. As a result, a fan impeller with good cooling efficiency and a fan motor using the same can be realized.
[0048]
Furthermore, in the motor unit in the above embodiment, the case where a sleeve bearing which is a sliding bearing is used as a bearing for supporting the rotating shaft is shown, but this may be a form using a pair of ball bearings, or A hydrodynamic bearing may be used. In the embodiment, the motor unit is an outer rotor type motor, but may be configured as an inner rotor type motor.
[0049]
【The invention's effect】
As described above, according to the fan motor of the present invention, since the fan impeller that is longer in the axial direction than the conventional centrifugal fan is configured to rotate at high speed, the windage loss or the like on the wall surface of the end wall portion is reduced. An unprecedented high static pressure fan motor can be realized, and a pair of fan impellers that are rotated on each side of the rotary drive unit are provided, so that the required air volume can be secured despite high static pressure, resulting in density It is possible to cool a small electronic device or electronic device with high efficiency at several times the conventional efficiency.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram showing a first embodiment of a fan motor of the present invention.
FIG. 2 is a longitudinal sectional view showing details of FIG. 1;
FIG. 3 is a side view of FIG. 2;
4 is a perspective view of a casing for explaining a state of the airflow of FIG. 1. FIG.
FIG. 5 is a partial longitudinal sectional view showing a second embodiment of the fan motor of the present invention.
FIG. 6 is a schematic block diagram showing a third embodiment of the fan motor of the present invention.
FIG. 7 is a longitudinal sectional view showing a fourth embodiment of the fan motor of the present invention.
FIG. 8 is a plan view of a conventional centrifugal fan motor.
FIG. 9 is a longitudinal sectional view cut along line X-O-YZ of FIG.
[Explanation of symbols]
10, 110, 210 casing
11, 12, 211, 212 Impeller cover
13, 14, 213, 214 Inlet
15,16 Exhaust port
20,120A, 120B, 220A, 220B Motor part
21, 221A, 221B Housing
22, 222A, 222B Stator
24,224A, 224B Rotating shaft
25, 225A, 225B Rotor magnet
30, 40, 130, 140, 230, 240 Fan impeller
31,41,231,241 end wall
32, 42, 232, 242 Impeller blades

Claims (6)

A fan motor for cooling portable electronic devices or small devices,
A rotary drive unit having a rotary shaft having load connecting ends on both sides in the axial direction, a pair of centrifugal fan impellers connected to both ends of the rotary shaft and rotating together with the rotary shaft, the rotary drive unit and both A casing that covers the fan impeller and has an air inlet and an air outlet,
Each of the pair of fan impellers has a disk-like end wall portion to which a rotating shaft is connected, and a circumferentially extending around the axis of the rotating shaft extending in the axial direction so as to rise from the outer peripheral portion of the end wall portion. A plurality of impeller blades arranged in the axial direction length of each impeller blade is set to be greater than or equal to the outer diameter of the circle formed by each impeller blade,
In the casing, an air inlet is formed facing an opening formed on the opposite side to the end wall portions of both fan impellers, and an air outlet is formed facing the outer peripheral portion of both fan impellers. And
By rotating the fan impeller, air is sucked into the fan impeller through the opening from the intake port of the casing, and air pushed from the impeller blades of the fan impeller in the outer peripheral direction is discharged from the exhaust port of the casing. Features a fan motor. The rotation drive unit includes a pair of magnetic circuit units including a stator drive coil supported by a fixed unit and a rotor magnet provided on the rotor, and rotates together with the rotor. The fan motor according to claim 1, wherein the shaft is rotatably supported by the fixed portion so as to penetrate the rotation drive portion, and both axial ends of the rotation shaft are led out from the rotation drive portion, and a fan impeller is connected to each. The rotation drive unit includes two sets of magnetic circuit units each including a stator having a drive coil supported by a fixed unit and a rotor magnet provided on the rotor. The rotation rotates integrally with each rotor. The fan motor according to claim 1, wherein the shaft is rotatably supported by the fixed portion, the end of each rotating shaft is led out from the rotation driving portion, and the fan impeller is connected. The rotational drive unit is composed of a pair of motor units having the same shape and leading end portions of the rotary shafts at the respective distal end portions, and both motor portions are integrally connected with their respective base end portions back to back. The fan motor according to claim 1 or 3, wherein a fan impeller is connected to the respective rotary shaft end portions of both motor portions. The casing is formed in an elongated cylindrical shape, and intake ports are formed at both ends in the longitudinal direction, and two exhaust ports respectively opposed to the pair of fan impellers are arranged at the same rotational position with respect to the shaft center on the side surface of the casing. The fan motor according to claim 1. The casing is formed in an elongated cylindrical shape, and air inlets are formed at both ends in the longitudinal direction, and two exhaust ports respectively facing the pair of fan impellers are at different rotational positions with respect to the axial center on the side surface of the casing. The fan motor of Claims 1-4 arrange | positioned.

Images