JP2006025563A - Brushless motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a brushless motor mounted in a portable personal computer that is low in loss and light in weight. <P>SOLUTION: The brushless motor includes: a rotor magnet 8 attached to the inner surface of a rotor; a rotating shaft 6 bonded to the rotor; an armature having winding coils 3 and laminated cores 4 in multiple phases disposed opposite to the inner circumferential surface of the rotor magnet 8; and the like. One or more non-magnetic layers 9 are formed in the laminated cores 4. By this constitution, a brushless motor wherein loss generated in the laminated core is reduced and further the effect of motor weight reduction is brought about is obtained. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a spindle motor used for rotationally driving an optical disc such as a digital video disc (DVD) recently installed in a portable personal computer.

  2. Description of the Related Art Conventionally, a brushless motor used for a disk drive or the like is configured as shown in FIG. 2 (refer to page 5 of FIG. 1 and FIG. 1).

  FIG. 2 shows the structure of a conventional brushless motor. In FIG. 2, the brushless motor has a configuration in which a stator holding portion, a rotor portion, and a spindle motor for rotating an optical disc or the like are omitted here, but a disc holding mechanism is provided on the upper portion of the rotor. The stator portion includes a stator substrate 1 having electrical wiring, a housing 2 attached to the stator substrate 1 by caulking or the like, a winding coil 3 fixedly disposed on the outer periphery of the housing 2, and an armature having a laminated core 4; The housing 2 includes a bearing 5 formed by press fitting or the like. On the other hand, the rotor portion has a rotating shaft 6 rotatably held by a bearing 5, a rotor frame 7 attached to the rotating shaft 6, and a rotor magnet 8 provided on the inner periphery of the rotor frame 7 so as to face the armature. And.

The conventional brushless motor is configured as described above, and the multi-phase winding coil 3 is sequentially energized by a drive circuit (not shown) or the like, and acts on the rotor magnet 8 to generate rotational torque in the rotor. The brushless motor is configured as described above.
Japanese Patent Laid-Open No. 7-194080

  However, brushless motors recently used for optical disk drive devices and hard disk drives mounted on portable personal computers and the like are becoming smaller and lighter, and at the same time, a reduction in the loss of the entire motor is required. In the above conventional configuration, there has been a problem that iron loss generated in a laminated core that accounts for most of the loss other than the motor drive circuit, that is, eddy current loss and hysteresis loss, is increased due to high rotation of the brushless motor.

  The present invention solves such a conventional problem. By providing at least one nonmagnetic layer inside the laminated core, the present invention not only reduces iron loss generated in the laminated core but also, for example, aluminum. It is an object of the present invention to provide a brushless motor that can be reduced in weight by using a metal having a low specific gravity such as an alloy for a nonmagnetic layer.

  In order to solve the above-described problems, the present invention includes at least one nonmagnetic layer in the laminated core, thereby suppressing the generation of eddy currents caused by the interaction between the laminated cores, and reducing eddy current loss. Reduced.

  According to the first aspect of the invention, not only the iron loss generated in the laminated core is reduced, but also an advantageous effect of reducing the weight of the motor is obtained by using a metal having a low specific gravity such as an aluminum alloy for the nonmagnetic layer. It is done.

  The invention according to claim 1 of the present invention includes a rotor magnet mounted on the inner surface of the rotor and a rotating shaft fixed to the rotor, and a plurality of phases arranged opposite to the inner periphery of the rotor magnet. In a brushless motor having an armature having a winding coil and a laminated core, the brushless motor is provided with at least one nonmagnetic layer inside the laminated core, and iron loss generated in the laminated core is reduced. In addition, for example, using a metal having a low specific gravity such as an aluminum alloy for the nonmagnetic layer has an effect of reducing the weight of the motor.

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

  FIG. 1 shows a cross section of the brushless motor of the present invention. In FIG. 1, the stator substrate 1, the housing 2, and the bearing 5 are the same as those in the conventional example, and thus description thereof is omitted here. The armature fixedly arranged on the outer periphery of the housing 2 is composed of a winding coil 3 and a laminated core 4, and here, a nonmagnetic aluminum alloy layer 9 is laminated so as to sandwich the laminated core 4. . On the other hand, the rotor is arranged in a plurality of winding coils 3 of the stator with a gap, and is composed of a rotor magnet 8 and a rotating shaft 6 fixed to the rotor frame 7, and the bearing 5 can freely rotate the rotating shaft 6. Is supported. The brushless motor is configured as described above.

  With the above configuration, not only the iron loss generated in the laminated core 4 is reduced, but also the weight can be reduced by using a metal having a low specific gravity such as an aluminum alloy for the nonmagnetic layer 9.

  The brushless motor of the present invention has an effect of low loss and light weight, and is useful as a brushless motor used for rotationally driving an optical disk or a hard disk mounted on a portable personal computer or the like.

Sectional drawing which shows the brushless motor by Example 1 of this invention Cross-sectional view of a conventional brushless motor

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Stator board 2 Housing 3 Winding coil 4 Laminated core 5 Bearing 6 Rotating shaft 7 Rotor frame 8 Rotor magnet 9 Nonmagnetic layer

Claims (2)

An armature having a rotor magnet mounted on the inner surface of the rotor and a rotating shaft fixed to the rotor, and having a multi-phase winding coil and a laminated core disposed to face the inner periphery of the rotor magnet. A brushless motor having at least one nonmagnetic layer in the laminated core. The brushless motor according to claim 1, wherein the nonmagnetic layer has the same shape or a cylindrical shape as the laminated core.