JP5200521B2 - Motor and cooling fan - Google Patents

Description

  The present invention relates to a motor and a cooling fan using the motor, and more particularly to a connection structure between a coil wire wound around a stator core constituting the motor and a circuit board.

  In recent years, many electronic devices are provided with a cooling fan for cooling electronic components in a casing. In particular, as the performance of electronic devices increases, the processing speed of arithmetic processing units such as CPUs increases, and as their heat generation increases, high-performance cooling fans are required. On the other hand, with the reduction in the cost of electronic equipment, the cooling fan is also required to reduce the cost.

  As a basic structure of a cooling fan of an electronic device, an impeller is fixed to the rotor side of the motor, and the stator side (armature) of the motor is mainly composed of a stator core, an insulator, and a coil. The stator core has a plurality of pole teeth protruding radially outward from the central axis, and the insulator covers a portion excluding the outer peripheral surface and the like of the stator core. The coil is wound around each pole tooth via an insulator.

  The stator coil as described above is electrically connected to a land provided on the circuit board by soldering. The circuit board has a circuit pattern made of copper foil on one or both sides of a substrate such as glass epoxy or paper phenol, and a hall element for detecting the rotational phase of the rotor, or a coil based on its output signal. An electronic component such as a drive IC for controlling a current to be supplied is mounted.

As a conventional structure for connecting the end of a coil (electric wire) of a stator to a land of a circuit board, a structure as described in Patent Document 1 is common. That is, a plurality of terminal pins for connection are inserted and fixed to an insulator placed on the stator core, and an end portion of the coil is wound around the terminal pins to perform connection by soldering. The terminal pins are fixed so as to protrude from the end surface of the insulator on the circuit board side. A plurality of through holes for inserting terminal pins and solder formed around each through hole are provided at corresponding positions on the circuit board. Attached lands are provided. A plurality of terminal pins with the coil ends electrically connected are inserted into the insertion holes of the circuit board, and each terminal pin is soldered to each land, whereby the ends of the coil wires are electrically connected to the lands of the circuit board. Is done. It should be noted that the soldering of the coil ends wound around the terminal pins and the terminal pins can be performed simultaneously with the soldering of the terminal pins and the lands.
JP-A-9-285075

  As part of improving the performance of cooling fans, high-power cooling fans with increased airflow and static pressure require a large current to flow through the coil, so the coil is wound using a thick wire. . In this case, the following problem may occur in the structure in which the end portion of the coil wire is electrically connected to the land of the circuit board via the terminal pin inserted into the insulator as described above.

  That is, when the end portion of the coil (electric wire) is wound around the terminal pin, bending stress is generated in the terminal pin due to the tension of the thick electric wire, and the terminal pin may be deformed (bent). Furthermore, when soldering between the end of the wound wire and the terminal pin, the insulator (resin molded product) into which the terminal pin is inserted is deformed by the heat and the tension of the wire, and the terminal pin may tilt from the root. is there. When the terminal pins are deformed (bent) or inclined as described above, it becomes difficult to insert the plurality of terminal pins into the plurality of insertion holes with lands provided in the circuit board.

  One way to avoid this problem is to solder the end of the wire directly to the land of the circuit board without using terminal pins when the coil is formed of a thick wire. However, in this case, after the connection by soldering, a stress is applied to the connection portion (soldering portion) between the conductive wire and the circuit board due to the tension of the electric wire, and there is a possibility that disconnection at the connection portion may occur.

  The present invention solves the conventional problems as described above, and devise a connection structure between the electric wire of the coil wound around the stator core and the circuit board, thereby using a motor with high reliability and low cost. An object is to provide a cooling fan.

  A motor according to an embodiment of the present invention is a motor including a stator portion arranged around a central axis and a rotor portion rotating around the central axis, and an electric wire is wound around the stator portion. A resin core including a plurality of protrusions around which end portions of the electric wires are wound, and a stator core having a coil constituted by a circuit board provided with a land to which the electric wires are electrically connected. A plurality of through-holes or notches through which the protrusions are inserted are formed at positions corresponding to the plurality of protrusions of the circuit board, which are fixed to the stator core, and the ends of the electric wires are A second surface that is an opposite surface on which the stator core is disposed from a first surface that is the surface on which the stator core is disposed on the circuit board through the through hole in a state of being wound around the protrusion. Guided, characterized in that it is connected to the land provided on the second surface.

  According to such a structure, since the end portion of the coil wire is directly connected (for example, soldered) to the land of the circuit board without using the terminal pin as in the conventional structure, the above-mentioned phenomenon is caused by the deformation or inclination of the terminal pin. Such a problem does not occur. In addition, since the wire end of the coil is guided to the land of the circuit board while being wound around the protrusion of the resin member, the tension of the coil is not directly applied to the connecting portion between the end of the wire and the land of the circuit board. , Disconnection at the connection is less likely to occur. This makes it possible to provide a motor with high reliability and productivity.

  In a preferred embodiment, the coil is configured by winding the electric wire around the stator core via a resin insulator, and the resin member including the plurality of protrusions is the same member or an integral member of the insulator. It is a member. In other words, the plurality of protrusions are formed on an insulator which is a resin molded product. Alternatively, the resin member including the plurality of protrusions and the insulator are integrated with each other by means such as adhesion or fitting.

In a further preferred embodiment, the stator core has a plurality of pole teeth arranged so as to be spaced apart in the circumferential direction, and the protrusion is provided between the adjacent pole teeth .

  In a further preferred embodiment, a groove or step for guiding the end of the electric wire is formed on the tip surface of the protrusion. Thereby, workability | operativity at the time of soldering with the edge part of an electric wire and the land of a circuit board improves. As a result, it is possible to provide a motor with high reliability and low cost.

  In a further preferred embodiment, the circuit board is a single-sided printed wiring board. Moreover, it is preferable that printed wiring is arranged on the second surface of the circuit board. Furthermore, it is preferable that the circuit board is a printed wiring board of a paper phenol base. With these configurations, the cost of the circuit board can be reduced and the productivity can be improved, and a low-cost motor can be provided.

  In a further preferred embodiment, a central hole is formed at substantially the center of the circuit board, and the notch is formed so as to be continuous from the outer periphery of the central hole. With such a configuration, the cost of the circuit board can be reduced and the productivity can be improved, and a low-cost motor can be provided.

  A cooling fan according to the present invention includes the motor as described above, and an impeller fixed to a radially outer side of a rotor holder that holds a rotor magnet constituting the rotor portion.

  According to the motor and the cooling fan of the present invention, the terminal end of the coil is led to the land of the circuit board in a state of being wound around the resin protrusion without using the terminal pin as in the conventional structure. Therefore, the tension of the coil is not directly applied to the connection portion between the end portion of the electric wire and the land of the circuit board, and disconnection at the connection portion hardly occurs. This makes it possible to provide a low-cost motor with high reliability and productivity.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic plan view of a cooling fan using a motor according to an embodiment of the present invention, and FIG. 2 is a schematic sectional view of the cooling fan. The cooling fan is an axial fan in which a motor 2 and an impeller 4 are incorporated in a housing 1 that is a resin molded product.

  The housing 1 includes a cylindrical portion 11 having a substantially square outer shape and a substantially circular inner peripheral surface in plan view, a circular base portion 12 arranged in the center of the housing 1 and a plurality of (for example, four). The connecting portion 13. Holes 111 for inserting bolts for attaching the cooling fan to the electronic device are provided at four corners of the substantially square shape in plan view of the cylindrical portion 11. The circular inner peripheral surface 112 in a plan view of the cylindrical portion 11 is a substantially cylindrical inner peripheral surface facing the outer peripheral edge of the impeller 4 with a predetermined gap therebetween, and is sent in the axial direction by the rotation of the impeller 4. It constitutes an air passage. The housing 1 is not limited to a resin molded product, but may be molded by aluminum die casting. The cylindrical portion 11, the base portion 12, and the connecting portion 13 of the housing 1 are integrally formed by resin injection molding or aluminum die casting.

  The base portion 12 of the housing 1 is supported at the inner central portion of the cylindrical portion 11 by a plurality of connecting portions 13, and the motor 2 is held by the base portion 12. A cylindrical part 121 centered on the central axis AX is provided at the center of the base part 12, and a pair of bearings 22 for rotatably supporting the rotary shaft 21 of the motor 2 (and the impeller 4) are mounted therein. Yes. The pair of bearings 22 are disposed so as to be separated in a direction along the central axis AX, and are fixed to the inside of the cylindrical member 221. The cylindrical member 221 is inserted inside the cylindrical portion 121 of the housing 1 and fixed as a unit. Further, a ring member 211 for preventing removal is attached to the proximal end portion of the rotating shaft 21. In the direction along the central axis AX (axial direction), the side where the base portion 12 and the connecting portion 13 of the housing 1 are located is referred to as a proximal end side, and the opposite side is referred to as a distal end side.

  An iron (for example, SUS) rotor holder 25 is fixed to the distal end side of the rotating shaft 21. The rotor holder 25 has a central portion 251 fixed to the rotary shaft 21, a disc portion 252 that extends in a substantially disc shape radially outward, and a cylindrical portion 253 that bends and extends from the outer peripheral portion to the proximal end side. The outer peripheral portion of the substantially cylindrical rotor magnet 26 is fixed and held on the inner peripheral surface of the cylindrical portion 253. The rotor magnet 26 is magnetized to four poles.

  The impeller 4 is fixed to the outer side (outer peripheral surface) of the rotor holder 25. The impeller 4 is a resin molded product, and includes a cylindrical portion 41 that covers the outer surface of the cylindrical portion 253 of the rotor holder 25, and a plurality that is arranged in the circumferential direction centering on the rotation shaft 21 that extends radially outward from the outer peripheral surface thereof. 1 (11 sheets in the example of FIG. 1).

  Next, the structure of the motor 2 will be described with reference to FIGS. FIG. 3 is a perspective view of the stator portion constituting the motor 2 as viewed from the base end side in the central axis AX direction. FIG. 4 is a plan view of the stator portion as seen from the base end side in the direction of the central axis AX. In both cases, the actual stator portion is schematically illustrated in a simplified manner.

  The motor 2 includes a stator portion centered on the central axis AX and a rotor portion that rotates about the central axis AX. The rotor portion includes a substantially cylindrical rotor magnet 26 and a rotor holder 25 having a cylindrical portion 253 that holds the outer periphery of the rotor magnet 26, and the stator portion includes a stator core 32 around which the coil 31 is wound, and a coil 31. And a circuit board 35 provided with lands 351 to which the wire end portions 311 are electrically connected.

  The stator core 32 has a plurality of (four) pole teeth 321 extending radially outward from four locations in the circumferential direction around the center axis AX, and the coil 31 is wound around each pole tooth 321. The stator core 32 is formed by laminating a plurality of electromagnetic steel plates in the direction of the central axis AX, and each electromagnetic steel plate has four portions forming the pole teeth 321 from the outer periphery of the donut-shaped portion at 90 ° intervals. It has a shape extending radially outward. The stator including the stator core 32 is a base portion of the housing 1 such that a central cylindrical portion of the stator core 32 configured by stacking donut-shaped portions is fitted around the cylindrical portion 121 of the base portion 12 of the housing 1. 12 is fixed.

  The stator core 32 is covered with an insulator 33 (a distal-side insulator 33D and a proximal-side insulator 33P), which is a resin insulator, from both sides in the axial direction, and a coil 31 is wound thereon. The outer circumferential surface of the stator core 32 (pole teeth 321) is exposed at the radially outer end surface of the electromagnetic steel sheet.

  The cooling fan motor 2 of this embodiment is a four-pole four-slot single-phase full-wave (or two-phase half-wave) motor. The stator core 32 is provided with four pole teeth 321, and each pole tooth 321 has a coil. 31 is wound. The four coils 31 are connected in series, and the two coil wire end portions 311 are drawn out. However, in FIG. 3, only one of the two coil wire end portions 311 is depicted.

  The circuit board 35 to which the wire end 311 of the coil 31 is electrically connected is provided with a Hall IC that detects a change in magnetic flux accompanying the rotation of the rotor magnet 26 of the motor 2 and the supply to the coil 31 based on the output signal. Circuit components such as a motor driving IC for controlling current are mounted. In the motor 2 of the cooling fan of the present embodiment, an inexpensive paper-phenol-based single-sided printed wiring board is used as the circuit board 35, and is on the side opposite to the first surface, which is the surface on which the stator core 32 is disposed. The printed wiring is arranged on the second surface which is the surface.

  Therefore, the wire end portion 311 of the coil 31 is led from the first surface of the circuit board 35 to the second surface, and is landed on the land (copper exposed copper foil portion at the printed wiring end portion) 351 provided on the second surface. Connected by soldering. More specifically, the wire end 311 is wound around the protrusion 331 formed on the base-end insulator 33P, and is guided to the second surface of the circuit board 35 through the through hole or notch of the circuit board 35. It is burned. By doing so, the tension of the coil 31 is not directly applied to the connection portion between the wire end portion 311 and the land 351 of the circuit board 35, and disconnection at the connection portion hardly occurs. This makes it possible to provide a motor with high reliability and productivity.

  FIG. 5 is a plan view showing a schematic shape of the circuit board 35. The circuit board 35 has a substantially circular outline, and a central hole 352 is formed at the center thereof. The cylindrical portion 121 of the base portion 12 of the housing 1 is inserted into the central hole 352 (see FIG. 2). A notch 353 into which the protrusion 331 is inserted is formed at two locations continuous from the outer periphery of the central hole 352, and a land to which the wire end 311 of the coil 31 is soldered in the vicinity of each notch 353. 354 is formed. Square holes 355 formed at three locations spaced apart by 90 degrees in the circumferential direction of the circuit board 35 are for engaging engagement claws (described later) formed in the proximal end insulator 33P.

  Next, the shape of the proximal-side insulator 33P, in particular, the shape of the protrusion 331 around which the wire end 311 of the coil 31 is wound will be described with reference to FIGS. FIG. 6 is a three-dimensional model diagram showing the shape of the proximal insulator 33P, and FIG. 7 is an enlarged perspective view showing the shape of the protrusion 331. As shown in FIG.

  The proximal insulator 33 </ b> P includes a cylindrical portion 332 that is fitted on the central cylindrical portion of the stator core 32, and four arm portions 333 that cover the four pole teeth 321 of the stator core 32. The coil 31 is wound around the constricted portions of the four arm portions 333. This basic shape is the same for the tip-side insulator 33D.

  Of the four arm portions 333 of the proximal-side insulator 33P, the engagement claws 334 projecting toward the proximal end are formed at the three radial distal ends. These three engaging claws 334 are inserted into the square holes 355 of the circuit board 35 described above and engage with each other. Thereby, the stator part of the motor 2 including the base end side insulator 33P and the circuit board 35 are fixed to each other.

  Further, the protrusion 331 around which the wire end 311 of the coil 31 is wound protrudes radially outward from the outer peripheral surface of the cylindrical portion 332 and then protrudes to the proximal end side. That is, the protrusion 331 is formed so as to be substantially L-shaped in a cross section including the central axis AX. In addition, on the outer peripheral surface of the cylindrical portion 332, the protruding portions 331 are arranged at two positions between the adjacent arm portions 333 (that is, between the adjacent pole teeth 321 of the stator core 32). If the protrusion 331 is provided at a circumferential position that overlaps with the arm 333, a mold for manufacturing the proximal insulator 33P is complicated by resin injection molding. That is, a slide core for undercut processing is required. Further, when the coil 31 is wound around the constricted portion of the arm portion 333, it is difficult to wind the coil 31 while avoiding the protruding portion 331 by the automatic winding machine. Or the effective width which can wind a coil around arm part 333 becomes narrow (a coil occupation rate falls). In the base end side insulator 33P of the present embodiment, the above-described problem is avoided by arranging the protruding portion 331 between the adjacent arm portions 333.

  FIG. 7 shows an example of the shape of the protrusion 331. In FIG. 7, a thick line 311T with an arrow schematically shows a direction and a state in which the wire end 311 of the coil 31 is wound around the protrusion 331. The protruding portion 331 is formed so as to protrude outward in the radial direction from the outer peripheral surface 332a of the cylindrical portion 332 of the base end side insulator 33P and toward the base end side. A stepped portion 331 a for guiding the wire end portion 311 is formed on the proximal end side distal end surface of the protruding portion 331. In the illustrated example, the wire end 311 of the coil 31 is wound around the protrusion 331 only once, but may be structured to be wound twice or more.

  In FIG. 7, the semicylindrical outer peripheral surface 331b of the protrusion 331 corresponds to the semicylindrical inner peripheral surface of the notch 353 formed in the circuit board 35 shown in FIG. The outer peripheral surface 332b constituting the step provided on the proximal end side of the cylindrical portion 332 is a surface that is in radial contact with the inner peripheral surface of the central hole 352 of the circuit board 35, and also forms the step. The flat surface 332 c is a surface that is in axial contact with the first surface around the central hole 352 of the circuit board 35.

  As described above, in the motor 2 of the cooling fan according to the present embodiment, the wire end 311 of the coil 31 is wound around the protrusion 331 formed on the base end insulator 33P that covers the stator core 32, and the circuit board 35 is cut. It is guided to the opposite surface (second surface) of the circuit board 35 through the notch 353 and soldered to the land 351. Therefore, the tension of the coil 31 is not directly applied to the connection portion between the wire end portion 311 and the land 351 of the circuit board 35, and disconnection at the connection portion is unlikely to occur. In addition, there is a problem that may occur when connecting the wire end of the coil and the land of the circuit board via the metal terminal pin inserted in the proximal insulator as in the conventional motor, that is, the terminal There is no problem that it becomes difficult to insert the terminal pin into the insertion hole with the land of the circuit board due to the deformation or inclination of the pin. This makes it possible to provide an inexpensive motor with high reliability and productivity.

  As mentioned above, although preferable embodiment of this invention was described, the motor and cooling fan of this invention can be implemented with a various form not only said embodiment.

  For example, in the above embodiment, the notch 353 is formed around the central hole 352 of the circuit board 35 through the protrusion 331 around which the wire end 311 of the coil 31 is wound, but instead of the notch 353. As shown in FIG. 8, the through hole 353 ′ may be formed near the central hole 352.

  In the above embodiment, the step 331a for guiding the wire end 311 is formed at the tip of the protrusion 331. However, this step may be omitted. FIG. 9 shows a perspective view (corresponding to FIG. 3) schematically showing the stator part in which the step 331a at the tip of the protruding part 331 is omitted. Although not shown, a groove for guiding the wire end 311 may be formed at the tip of the protrusion 331 instead of the step 331a.

  In the above embodiment, the protrusion around which the wire end 311 of the coil 31 is wound is formed integrally with the base end insulator 33P. However, the protrusion is provided on a resin member different from the base end insulator 33P. Also good. For example, a resin member having a protruding portion may be manufactured as a resin molded product different from the insulator, and the resin member and the insulator may be integrally coupled by means such as fitting or adhesion.

  In the above embodiment, the protrusion 331 is disposed between the adjacent arm portions 333 of the proximal insulator 33P (that is, between the adjacent pole teeth 321 of the stator core 32). The protruding portion 331 may be disposed at the radially outer tip of the pole teeth 321 of the stator core 32. In this case, the engaging claws 334 formed at the distal end in the radial direction of the proximal-side insulator 33P and the projections 331 may be arranged side by side, or may be configured such that both are integrated. FIG. 10 is a cross-sectional view (corresponding to FIG. 2) of the cooling fan showing an example of such a configuration.

  Further, in the embodiment shown in FIGS. 2 and 10, the proximal end side distal end surface of the protrusion 331 slightly protrudes from the second surface of the circuit board 35, but does not protrude, that is, both are flush with each other. You may comprise.

  In the above embodiment, a paper phenol base single-sided printed wiring board is used as the circuit board 35, but a glass epoxy base circuit board or the like may be used, or a double-sided printed wiring board is used. May be.

  The cooling fan in which the motor of the present invention is used is not limited to the axial fan as described in the above embodiment, but may be a centrifugal fan.

It is a schematic plan view of the cooling fan using the motor which concerns on embodiment of this invention. It is a schematic sectional drawing of the cooling fan which concerns on embodiment of this invention. It is the perspective view which looked at the stator part which comprises a motor from the axial direction base end side. It is the top view which looked at the stator part which comprises a motor from the axial direction base end side. It is a top view which shows schematic shape of a circuit board. It is a three-dimensional model figure which shows the shape of a base end side insulator. It is an expansion perspective view which shows the shape of the projection part of a base end side insulator. It is a top view which shows schematic shape of the circuit board which concerns on another embodiment. It is a perspective view of the stator part which concerns on another embodiment. It is sectional drawing of the cooling fan which concerns on another embodiment.

Explanation of symbols

2 Motor 31 Coil 32 Stator core 33 Insulator 35 Circuit board 33P Base end side insulator 33D End side insulator 311 Coil end of wire 321 Stator core pole teeth 331 Protruding part 331a Step part 351 Land 353 Notch 353 'Through hole AX Center shaft

Claims (6)

A motor comprising a stator portion arranged around a central axis and a rotor portion rotating around the central axis,
The stator portion includes a stator core having a coil formed by electrodeposition through a resin insulator wire is wound, and a circuit board land is provided with the electric wire are electrically connected,
A resin member including a plurality of protrusions around which the ends of the electric wires are wound is fixed to the stator core,
The resin member including the plurality of protrusions is the same member as the insulator or an integral member,
The stator core has a plurality of pole teeth arranged so as to be separated from each other in the circumferential direction, and the protrusion is provided between the adjacent pole teeth,
The insulator has a cylindrical portion that is fitted around the central cylindrical portion of the stator core,
The protruding portion protrudes radially outward from the outer peripheral surface of the cylindrical portion, and then protrudes in the central axis direction.
A groove or step for guiding the end of the electric wire is formed on the tip surface of the protrusion,
A plurality of through holes or notches through which the protrusions are inserted are formed at positions corresponding to the plurality of protrusions of the circuit board,
The stator core is disposed from the first surface, which is the surface of the circuit board on the side where the stator core is disposed, through the through hole or the notch while the end of the electric wire is wound around the protrusion. A motor which is guided to a second surface which is an opposite surface and is connected to the land provided on the second surface.   The motor according to claim 1, wherein the circuit board is a single-sided printed wiring board.   The motor according to claim 1, wherein printed wiring is disposed on the second surface of the circuit board.   4. The motor according to claim 3, wherein the circuit board is a printed wiring board made of paper phenol.   The center hole of the said circuit board is formed in the approximate center, The said notch is formed so that it may continue from the outer periphery of the said center hole, The any one of Claim 1 to 4 characterized by the above-mentioned. The motor described.   6. A cooling fan comprising: the motor according to claim 1; and an impeller fixed to a radially outer side of a rotor holder that holds a rotor magnet constituting the rotor portion.

Images