JP2005184909A - Outer rotor type brushless motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an outer rotor type brushless motor which avoids the interference of respective components and the contact of a fixed part with a rotary part except a necessary part even when the interval of the respective parts for reducing the size is narrowed and which electrically insulates except the necessary part. <P>SOLUTION: The outer rotor type brushless motor includes a core made of a magnetic material fixed to a bracket, a coil formed by winding an electric wire on the core, and a rotor including a magnet part disposed at the outside of the core through an air gap. A columnar stepped part is provided at the bracket. The end of the core is bumped against the columnar stepped part to be positioned at the intermediate part between the coil and the other coil not so as to perform the interference with the coil and the contact with the coil. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a structure of a cored outer rotor type brushless motor used for disk drive of an information storage device.

  An example of a conventional outer rotor type brushless motor (hereinafter abbreviated as a brushless motor) is shown in FIG.

  As shown in the assembly diagram of FIG. 5 (4), the conventional brushless motor has a core 1, a coil 2, a crossover 3, a bracket 4, a stepped portion 5, a magnet 6, a yoke 7, a hub 8, a shaft 9, a bearing 10, and a bearing. 11.

  Next, the contents of the brushless motor will be described with reference to FIGS.

  First, the core 1 is made of a magnetic material such as a silicon steel plate. The core 1 is insulated with an epoxy resin or the like, and then an electric wire with an insulating film is wound thereon to form the coil 2. The coils are electrically connected to each other by the connecting wire 3 shown in FIG. Here, the number of coils 2 is a natural integer multiple of the number of simultaneously energized phases, and FIG. 5 shows a case of three-phase nine coils.

  FIG. 5 is a diagram showing the components and assembly drawing of a brushless motor. (1) is a rotor that transmits rotation to the outside and rotates around a shaft 9, and (2) is a magnetic material such as a silicon steel plate. A core 1 in which an electric wire is wound to form a coil 2, and a bracket 4 for fixing the core 1 and the shaft 9 to each other are shown in (3), and (4) shows a diagram in which each is assembled.

  The core 1 in which an electric wire is wound around a magnetic material such as a silicon steel plate shown in FIG. 5 (2) is provided in a cylindrical shape by a method such as cutting after die-casting or forging of the bracket 4 as shown in (3). The core end portion 12 corresponding to the lower circumferential portion of the core 1 is abutted against the stepped portion 5 and positioned, and then fixed to the bracket 4 by a method such as UV anaerobic or epoxy bonding.

  Then, as shown in FIG. 5 (1), a magnet 6 is disposed outside the core 1 to which the bracket 4 is fixed, via a gap, and the magnet 6 is fixed to the hub 8 via a yoke 7 made of a magnetic material. The rotor thus rotated is rotatably supported by a shaft 9 fixed to the bracket 4 via a bearing 10 and a bearing 11, and as shown in FIG. 5 (4), the outer rotor type brushless motor is formed as a whole. Form.

  In recent years, with the miniaturization of information storage devices, the space allowed for motors has also become smaller, so it is necessary to reduce the spacing between components at the same time as miniaturization of the components used therein. Is in the situation. However, even when the interval is narrowed, interference between the components and contact between the fixed part and the rotating part other than the necessary part must be avoided, and at the same time, electrical insulation other than the necessary part must be achieved.

  FIG. 6 shows an assembly drawing of the core and the bracket. 6A is a core 1 in which an electric wire is wound around a magnetic material such as a silicon steel plate, FIG. 6B is a bracket 4 having a stepped portion 5 for abutting the core 1 on the circumference, and FIG. And the bracket 4 are combined and the stepped portion 5 of the bracket 4 is abutted against the core end portion 12 of the core 1 to perform positioning. In this case, the stepped portion 5 is on the back side of the coil 2, and the width W0 of the stepped portion 5 must be abutted against the core end 12 of the coil in the portion on the backside of the coil from the inside of the core.

  FIG. 7 shows the state of the crossover of the coil 2 in which the electric wire in the core 1 is wound. In the case of a three-phase nine-coil, each phase in the three phases is arranged in two jumps. Are connected by a crossover wire 3.

  For example, as a specific example, a coil in which coils wound around a, d, and g are connected is a U phase, and similarly, a coil of b, e, and h is connected to a V phase, and c, f, i These coils are connected to form a W phase.

  In the case of U phase in FIG. 7 (A), wires are wound around a, d, and g, and the connecting wire between them is the lower side 1) at b, the upper side 3) at c, and the lower side 2) at e. Then, wire so that it is on the upper side 4).

  Thereafter, the V phase (B) and the (C) W phase are similarly wired.

  For this reason, in the case of the U-phase in FIG. 7A, the crossover wires pass through the back side of the wound coils b and e, and portions 1) and 2) that are very close to the position of the stepped portion 5 are generated.

  Similarly, in the V layer of (B) and the W layer of (C), the connecting wire passing through the back side of the coil is very close to the step portion 5, and a part of the coil 2 and the connecting wire 3 are provided on the bracket 4. It is easy to generate an abnormality by contacting the stepped portion 5 or being sandwiched between the core 1.

  Accordingly, in the example shown in FIGS. 5 to 6 and 7, the distance between the coil 2 and the connecting wire 3 between the step portion 5 provided in a cylindrical shape on the bracket 4 is very narrow. At the time of mounting, the step portion 5 provided on the bracket 4 interferes with a part of the coil 2 and the crossover wire 3, and the core 1 cannot be accurately abutted against the core end portion 12, and cannot be fixed at a proper position. Things may occur.

When a part of the coil 2 and the crossover wire 3 come into contact with the stepped portion 5 provided in the bracket 4 or are sandwiched between the core 1 and the insulation film of the wire is broken, Since the material of the bracket 4 and the stepped portion 5 provided thereon is made of metal such as aluminum or zinc in order to obtain strength and accuracy, it is electrically connected to the coil 2 or the crossover wire 3, and the brushless motor is A situation that does not work properly occurs.
JP 2001-45727 A

  However, a part of the coil 2 and the crossover wire 3 come into contact with the stepped portion 5 provided in the bracket 4 or are sandwiched between the core end 12 of the core 1 due to the downsizing. In order to prevent this, if the stepped portion 5 is eliminated, the axial height of the core 1 with respect to the bracket 4 cannot be easily determined.

  Therefore, the present invention solves the above problems and avoids interference between parts and contact between the fixed part and the rotating part other than necessary parts even when the interval between the parts is narrowed for miniaturization, It is an object of the present invention to provide a brushless motor that achieves electrical insulation other than necessary parts.

  In order to achieve the above object, an outer rotor type brushless motor according to a first aspect of the present invention has a coil (coil 2) formed by winding an electric wire around a core (core 1), and the coils are arranged in a plurality of annular shapes. And an outer rotor configured by combining a bracket (bracket 4) for fixing each of the cores and a rotor (hub 8) disposed outside the core via a gap and having a magnet (magnet 6). In the type brushless motor, the bracket has a plurality of stepped portions (stepped portions 5) when the core is fixed, and the stepped portion has the electric wire wound around the core fixed to the bracket. It is formed at a position where it cannot be touched.

  In order to achieve the above object, an outer rotor type brushless motor according to a second aspect of the present invention is the outer rotor type brushless motor described in the first means, wherein the number of steps provided on the bracket is three. Thus, the total number of the coils is smaller.

  According to the brushless motor using the bracket of the shape according to the present invention, it is possible to obtain a highly reliable brushless motor in which the coil and the jumper wire are prevented from conducting due to interference and contact with the bracket stepped portion, and are small but do not malfunction. There is an effect that can be done.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings by way of preferred examples.

  First, an embodiment of a brushless motor is shown in FIGS.

  FIG. 1A is an example of a cross-sectional view of a brushless motor having a bracket shape according to the present invention, and FIG. 1B is a diagram showing a shape of FIG. 2 is an explanatory view in which FIG. 1 (A) is simplified and the core is mounted on the bracket, and FIG. 3 shows a further developed portion of the stator cut in FIG. 1 for each phase. FIG. 4 is a view showing a positioning state when the core and the bracket are brought into contact with each other.

  A core 1 made of a laminate of silicon steel plates, which is a magnetic material shown in FIG. 1 (A), is insulated by an epoxy resin around its entire periphery, and an electric wire having a polyurethane insulation film applied to a copper wire is wound around the core 1. The coil 2 is turned to form a coil 2, and the coils are electrically connected to each other by a crossover 3 shown in FIG. The number of phases and the number of coils in this example are three-phase nine coils.

  Next, the core 1 around which the electric wire is wound abuts against the columnar step portion 5 formed by cutting after forging the aluminum bracket 4 shown in FIG. It is fixed with an agent.

  At this time, in order to perform positioning accurately, notches 1a and 1b are provided inside the core 1 as shown in FIG. 4, and a positioning hole 4a corresponding to the notch is provided in the bracket 4.

  The step portion 5 has a shape in which the columnar upper portion abuts against the core end portion 12 of the core 1 in the middle between the coils as shown in (1), (2), and (3) of FIG. If the columnar step portion 5 formed on the bracket is included in the bracket forging or die-casting mold in advance, the manufacture becomes easy.

  Here, the step part 5 is installed in the middle of the coil so that the coil 2 does not interfere with or contact the step part 5. And in order not to produce the inclination at the time of abutting, as shown in FIG. 1 (B), the abutting stepped portions 5 may be installed at three places at intervals of 120 °, but even if they are installed at all intermediate portions of the coil. Of course it is good.

  FIG. 2 shows the abutting state of the core 1 and the bracket 4. In order to abut the core end portion 12 of the core 1 and the stepped portion 5 of the bracket 4, it is necessary to make the width as wide as possible. Since the width W1 of the stepped portion 5 in (2) is set in the middle between the coils, the width W1 of the stepped portion 5 is not the back side of the conventional coil. It can be extended to the outer periphery of the core, and the thickness of the cylindrical portion of the core 1 is also appropriate within that range.

  That is, W0 <W1 and a sufficient width can be taken for abutment. In addition, since the stepped portion 5 is provided between the coils, it is not necessary to abut the stepped portion 5 at the core end 12 on the back side of the coil. Therefore, the coil is sufficiently separated from the stepped portion 5 and is difficult to contact. The coil 2 is not sandwiched between the core end 12 and therefore, the structure is less likely to cause abnormality.

  Next, the relationship between the coil 2 and the crossover wire 3 with respect to the step portion 5 is shown in FIG. Since this explanation example is a three-phase nine-coil, one phase connects three coils arranged by jumping two other coils with a jumper 3. Specifically, the connection of coils wound around a, d, and g is the U phase, and the connection of b, e, and h coils is the connection of the V phase, c, f, and i. This is the W phase.

  If the connecting wire 3 is arranged so that the coils are connected in a straight line, the connecting wire 3 is radially inward from the inner diameter of the core and completely interferes with the bracket 4. Therefore, as shown in FIG. Wind about half a turn around the winding part of the other phase and arrange the crossover 3.

  Here, since each coil in one phase is wound in the same direction, in the case of three phases, between the coil of one coil and another other phase adjacent thereto, on the lower side of the core. There is a crossover that runs through the back of the coil.

  For example, after the U-phase electric wire is wound around the a part of the core, it passes through the lower side of the core and the back side of the coil to the adjacent b part. In the V phase, a connecting wire is arranged in the same manner as the U phase, but after the W phase is wound around the c portion of the core, it passes through the upper side of the core to the adjacent d portion and passes through the lower side at the next e portion.

  The positions (1), (2), and (3) of the three step portions 5 shown in FIG. 3 are abutting positions against the core end portion 12 between the coils while avoiding the back side of the coils. The columnar stepped portion 5 is not in contact with the connecting wire 1) and 2) passing through the back side of the coil.

  Next, FIG. 4 shows an alignment state when the core 1 and the bracket 4 are assembled. In this figure, notches 1a and 1b are added to a diagram substantially equivalent to FIG. 1B, and the layout of positioning holes 4a and mounting position holes 4b1, 2 and 3 of the bracket 4 is superimposed.

  First, the bracket 4 is positioned on the fixing jig by the positioning holes 4a and fixed by the three mounting holes 4b. After the notches 1a and 1b are pressed against the jig for the core 1 and positioned and attached, the core end 12 of the core 1 and the stepped portion of the bracket 4 are abutted and bonded and fixed in combination with the bracket 4.

It is a longitudinal cross-sectional view of the example of a brushless motor which concerns on this invention. It is a figure which shows the combination of the bracket and core which concern on this invention. It is an expanded view of the stator part which shows the coil and connecting wire of the brushless motor which concern on this invention. It is a figure which shows alignment with the core and bracket which concern on this invention. It is a figure which shows the structural part and longitudinal cross-section of the conventional brushless motor. It is a figure which shows the combination of the conventional bracket and core. It is an expanded view of the stator part which shows the coil and connecting wire of the conventional brushless motor.

Explanation of symbols

1 core (core)
1a, 1b Notch 2 Coil (Coil)
3 Crossover 4 Bracket (Bracket)
4a Positioning hole 5 Stepped part of bracket (Stepped part)
6 Magnet (Magnet)
7 Yoke 8 Hub (Rotor)
9 Shaft 10.11 Bearing 12 Core end

Claims (2)

A coil is formed by winding an electric wire around a core, the coil is arranged in a plurality of annular shapes, a bracket for fixing each of the cores,
A rotor disposed outside the core via a gap and having a magnet;
In an outer rotor type brushless motor configured by combining
The bracket has a plurality of step portions when fixing the core,
The stepped portion is formed at a position where the electric wire wound around the core fixed to the bracket is not touched. In the outer rotor type brushless motor according to claim 1,
The outer rotor type brushless motor, wherein the number of steps provided on the bracket is 3 or more and less than the total number of coils.

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