JP2007300772A - Brushless motor for disk driving - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a brushless motor capable of precious turntable fluctuation control and connection method simplification as a disk rotation motor for rotating optical disk drives like CD and DVD. <P>SOLUTION: A turntable 4 in a rotor frame 5 is provided with a V-shaped groove 32 or a number of concaves 34 or refined holes 35 on a circumference to weaken a mechanical strength in this portion so that the top panel of the rotor frame 5 can be easily deformed and fluctuation in the turntable 4 can be readily corrected after a shaft 8 is linked to the rotor frame 5. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention mainly relates to a structure of a brushless motor for driving a disk, which is mounted on a motor turntable or a hub or the like to record and reproduce information such as a compact disk, a video disk, or a magnetic disk. .

  FIG. 8 shows a conventional example of the structure of a disk rotating motor used in an optical disk apparatus such as a CD and a DVD. The disk rotation motor includes a rotor portion 29 and a stator portion 30. Among them, the rotor portion 29 is an integrated rotor frame 18 in which the turntable portion 17 and the yoke portion 19 are integrated, the turntable cushion 16 which is attached to the turntable portion 17 and whose surface is cut, and the disc together with the turntable cushion 16. The stator 30 is composed of a bearing 23, a housing 24 for holding the bearing 23, a winding 25, a laminated core 26, a bracket 27, and the like. Etc.

  In recent years, an increase in capacity of an optical disk device for mobile use has progressed dramatically, and along with this, an optical disk is also required to have a large capacity. As a result, the pit shape for recording a digital signal has been miniaturized, and the mechanical accuracy of a device for reproducing or recording the pit has become very strict. In order to satisfy the requirements, high precision is also required for the disk rotation motor, and one of the problems is to improve the surface runout of the turntable cushion on which the disk is mounted. If the surface runout accuracy is low, it may cause reading and writing errors of the optical disc.

In order to solve the above problem, in the conventional disk rotation motor shown in FIG. 8, the dimension of the portion into which the inner shaft 21 of the projecting annular portion 31 projecting from the center of the rotor frame 18 is press-fitted is constant. When the shaft 21 is fastened to the projecting annular portion 31 of the rotor frame 18 by light press-fitting, the deformation of the projecting annular portion 31 of the rotor frame 18 is suppressed, and the shaft 21 and the projecting annular portion 31 are set. The structure which implement | achieves high fastening intensity | strength and the high surface runout precision of a turntable part by filling an adhesive with the large diameter part of the inner periphery is proposed. (For example, see Patent Document 1)
JP 2002-136031 A (page 9, FIG. 1)

  However, in recent years, the volume of information has further increased, and a motor with higher accuracy has been demanded. Thus, as in the conventional technology described above, it is not possible to satisfy the requirements simply by suppressing the deterioration of surface runout at the time of fastening. ing.

  In order to solve the above problems, the present invention provides a circumferential strength reducing portion between a turntable portion integrally formed with the rotor frame on the top surface of the rotor frame and a shaft fixing portion of the rotor frame. .

According to the first to fourth aspects of the present invention, after the rotor frame and the shaft are fastened, the force is applied to the turntable portion with the strength reduction portion of the top surface of the rotor frame as a boundary based on the shaft. In a direction opposite to the tilt of the turntable portion with respect to the generated shaft, an inclination is generated between the turntable portion and the surface on the shaft fixing portion side from the strength reducing portion of the top surface of the rotor frame, so Correct so that the surface of the part where the cushion is applied is almost perpendicular to the shaft. As a result, after attaching the turntable cushion, when cutting the disc mounting surface of the turntable cushion perpendicularly to the shaft, it is possible to easily finish the surface runout accuracy with a small amount of cutting. An advantageous effect is obtained. In addition, since it is possible to correct the inclination after fastening, it is not necessary to increase the precision of the inclination at the time of fastening, and a simple fastening method may be used. For this reason, productivity can be improved.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(Embodiment 1)
1 is a structural sectional view of a motor according to Embodiment 1 of the present invention, and FIG. 2 is a plan view of a rotor frame which is a main part of the present invention. 3 and 4 are diagrams showing a method of correcting the rotor frame.

  In FIG. 1, a brushless motor for driving a disk includes a turntable cushion 3 on which a disk is mounted, a turntable portion 4 to which the turntable cushion 3 is attached, and a cup-shaped rotor frame 5 in which the turntable portion 4 is integrally formed. A rotor magnet 7 fixed to the inner periphery of the cylindrical yoke portion 6 of the rotor frame 5, a shaft 8 fixed to the center of the rotor frame 5, and a disk holding member 9 that presses and supports the disk together with the turntable portion 4. A rotor portion 1 including a shaft 10, a bearing 10 that rotatably supports the shaft 8, a housing 11 that holds the bearing 10, a laminated core 13 that is held by the housing 11, and a winding wound around the laminated core 13. A stator comprising a wire 12 and a bracket 14 for holding the housing 11 2, the rotor unit 1 is constituted by the retaining member 15 to prevent the break out of the bearing 10 of the stator unit 2, wherein the turntable 4, circumferential grooves 32 are formed.

By forming the groove 32, the mechanical strength between the turntable portion 4 on the top surface of the rotor frame 5 and the surface 5a on the fixed portion side of the shaft 8 partitioned by the groove 32 can be reduced. The top surface portion of the rotor frame 5 can be easily deformed with a small force. Therefore, for example, by applying a force to the turntable portion 4 with the receiving jig 33 as a reference at the groove 32 on the top surface of the rotor frame 5 with respect to the shaft 8, In the opposite direction, by generating an inclination between the turntable portion 4 and the surface 5 a on the fixed portion side of the shaft 8, the surface of the portion where the turntable cushion 3 is attached to the turntable portion 4 is perpendicular to the shaft 8. It can be corrected. Therefore, when the disk mounting surface of the turntable cushion 3 attached thereto is cut perpendicularly to the shaft 8, the surface runout accuracy can be easily finished with high accuracy with a small amount of cutting. The shape of the groove 32 can reduce the mechanical strength of the portion formed by any shape such as a V shape or a concave shape. As a result, it is possible to increase the accuracy of surface runout of the turntable portion 4 of the disk-less brushless motor.
(Embodiment 2)
Further, as shown in FIGS. 5, 6, and 7, it is also possible to form the turntable portion 4 by forming a plurality of concave portions 34 or through holes 35 arranged circumferentially.

  If the mechanical strength of the portion formed by either the recess or the through hole can be reduced, the above effect can be obtained.

  This is useful for a disk-less brushless motor for a mobile device that requires high accuracy of surface deflection of a turntable cushion such as a spindle motor for optical media.

Cross-sectional view of the structure of the motor according to Embodiment 1 of the present invention 1 is a plan view of a rotor frame according to Embodiment 1 of the present invention. The figure which shows the correction method of the rotor frame which concerns on Embodiment 1 of this invention (1) FIG. 2 shows a method for correcting a rotor frame according to Embodiment 1 of the present invention. Cross-sectional view of the structure of a motor according to Embodiment 2 of the present invention (1) Cross-sectional view of the structure of the motor according to Embodiment 2 of the present invention (2) Plan view of a rotor frame according to Embodiment 2 of the present invention Cross-sectional view of the structure of a conventional brushless motor

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,29 Rotor part 2,30 Stator part 3,16 Turntable cushion 4,17 Turntable part 5,18 Rotor frame 5a Fixed part side surface 6,19 Yoke part 7,20 Rotor magnet 8,21 Shaft 9,22 Disk holding member 10, 23 Bearing 11, 24 Housing 12, 25 Winding 13, 26 Laminated core 14, 27 Bracket 15, 28 Retaining member 31 Projecting annular portion 32 Groove portion 33 Receiving jig 34 Recessed portion 35 Through hole

Claims (4)

A turntable cushion for mounting a disk, a turntable portion for attaching the turntable cushion, a cup-shaped rotor frame integrally formed with the turntable portion, a rotor magnet fixed to the inner periphery of the rotor frame, and the rotor A rotor portion including a shaft fixed to the center of the frame, a disk holding member that presses and supports the disk together with the turntable cushion, a bearing that rotatably supports the shaft, a housing that holds the bearing, and a housing In the brushless motor for driving a disk constituted by a laminated core to be held, a winding wound around the laminated core, and a stator portion comprising a bracket for holding the housing, the turntable on the top surface of the rotor frame Part and shaft Brushless motor disc drive strength reducing section is formed circumferentially between the fixed parts. 2. The disk-less brushless motor according to claim 1, wherein the strength reducing portion of the rotor frame is a circumferential groove. 2. The brushless motor for driving a disk according to claim 1, wherein the strength reducing portions of the rotor frame are a plurality of concave portions arranged circumferentially. 2. The brushless motor for driving a disk according to claim 1, wherein the strength reducing portion of the rotor frame is a plurality of holes arranged in a circumferential shape.

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