JP2010252439A - Motor for disc drive - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a motor for disc drive, which can reduce the shaft fluctuations due to a clearance between a bearing and a shaft, and the cogging torque, and which can also be thinned. <P>SOLUTION: The angles of the salient poles of cores 6 are formed unequal, and a plate 12 is made of a magnetic material, and a cut 12a is created on a side which is located in a part of the plate 12 facing the end face of a rotor magnet 3 and in which the angle of the salient pole of the core 6 is small. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a disk drive motor used mainly in personal computers and AV equipment.

Disk drive devices used in personal computers and AV equipment are required to be smaller, thinner, higher density, and higher accuracy, and motors built into them are also required to be smaller, thinner, and higher accuracy. It was.
Among these requirements, in order to reduce the thickness, a rotor retaining stopper is arranged in the space between the inner diameter side of the stator winding of the core in which the stator winding is wound in the radial direction and the housing holding the bearing. A technology has been proposed that suppresses the increase in the height direction. (For example, refer to Patent Document 1).

  FIG. 3 shows the structure of a motor used in the disk drive device described in Patent Document 1. In FIG. 3, the rotor part has a turntable part and a yoke part integrally formed by pressing or the like, a rotor frame 32, a disc holding mechanism 35, a rotor magnet 33, a shaft 31, a TT cushion 34 for disc slip prevention, and a spring property. The disc holding mechanism 35 has a function of pressing and supporting the disc together with the turntable portion by a spring force. The stator part is a molded part made of sintered metal or the like, and a stator 39 is wound around a bearing 39 impregnated with oil, a housing 40 containing the bearing 39, and an insulator 37 as an insulating material on the core 36. And a substrate 41 for electrically connecting the ends of the stator windings 38 and a metal plate 42. The shaft 31 of the rotor portion is inserted into the bearing 39 of the stator portion, and the rotor portion is rotatably supported with the inner peripheral surface of the rotor magnet 33 and the core 36 facing each other. The housing 40 and the substrate 41 are fixed to the plate 42. An engaged portion 44 is formed radially outward at the end of the housing 40 facing the rotor frame 32 and engages with a retaining member 43 to prevent the rotor portion from slipping out of the stator portion. It constitutes a stop. A disk drive motor is constituted by the rotor part and the stator part. In a space between the inner diameter side of the stator winding 38 of the core 36 around which the stator winding 38 is wound and the housing 40 holding the bearing 39, the rotor composed of the engaged portion 44 and the retaining member 43 is prevented from coming off. Therefore, the bearing 39 and the retainer are not stacked in the height direction, so that the thickness can be reduced.

  However, in the conventional configuration described in Patent Document 1, when using a disk with a large unbalance, or when rotating at a low speed in order to print characters and pictures on the label surface of the disk with a laser, the bearing and shaft There was a problem that the shaft runout caused by the clearance of the disc became large, and the writing / reading accuracy of the disc was affected.

  In order to solve the problem of shaft runout caused by the bearing-shaft clearance, the core salient pole angles are formed unevenly and non-uniform attractive forces are generated in the radial direction with the opposed rotor magnets. A technique for absorbing the clearance between the bearing and the shaft by generating a radial biasing force has been proposed. (For example, refer to Patent Document 2).

  FIG. 4 shows the shape of the core of the motor used in the disk drive device described in Patent Document 2.

In FIG. 4, the left half of the core 46 has a shape in which the half of the core whose core salient pole is α ° and the right half of the core 46 whose core salient pole angle is β ° are combined. The attraction force acting between the core and the rotor magnet is unbalanced on the left and right, and the rotor portion to which the rotor magnet is attached is always in a state where a force that biases it in one direction in the radial direction is applied. As a result, the shaft is urged in one direction of the bearing, and the swinging of the shaft can be suppressed.

Furthermore, the number of salient poles of the core is 6n, the number of magnetic poles of the rotor magnet is 8n,
By setting the angle α−β = 15 ° / n, the two cogging torques having different phases by 180 ° are combined, and the cogging torques cancel each other and the cogging torque is reduced.

  According to such a configuration, when a disk with a large unbalance is used or when the disk is rotated at a low speed, shaft shake due to the clearance between the bearing and the shaft can be suppressed, and writing / reading accuracy can be improved. In addition, the cogging torque can be reduced.

JP 2003-32932 A Japanese Patent No. 3610667 (page 5, FIG. 1)

  However, in the case of reducing the thickness by combining the conventional technique described in the above cited document 1 based on the conventional configuration described in the above-mentioned Patent Document 2, or when further reducing the thickness, it is inevitable. Since the core thickness is reduced and the facing area between the core and the rotor magnet is reduced, the rotor part generated when the attractive force acting between the core and the rotor magnet becomes imbalanced on the left and right is set in one direction in the radial direction. The urging force is reduced, and there arises a problem that shaft runout caused by the clearance between the bearing and the shaft cannot be suppressed. In particular, in order to reduce the cogging torque at the same time, the angle difference between the salient poles of the left and right cores cannot be increased so much, and therefore the force for urging the rotor portion in one direction in the radial direction is likely to be reduced.

  The present invention solves such a conventional problem, and provides a disk drive motor that can reduce the shaft runout and cogging torque caused by the clearance between the bearing and the shaft, and can be reduced in thickness. The purpose is to do.

  In order to solve the above-described problems, the present invention is a part of a plate that is formed with a non-uniform salient pole angle of the core, the plate is made of a magnetic material, and is opposed to the end face of the rotor magnet. This is a disk drive motor having a structure in which a notch is formed on the side having a smaller salient pole angle.

According to the first aspect of the present invention, there is provided a force for biasing the rotor portion in one direction in the radial direction, which is generated when the attraction force acting between the core and the rotor magnet is imbalanced on the left and right sides, and one plate. The rotor part in the radial direction is combined with the force that urges the rotor part in one direction in the radial direction due to the attraction force acting between the plate and the end surface of the rotor magnet becoming unbalanced by cutting out the part. It is possible to increase the pressing force. With this configuration, it is possible to compensate for the force that presses the rotor portion, which is insufficient when reducing the thickness of the core by reducing the thickness of the core in the radial direction, thereby reducing shaft runout caused by the clearance between the bearing and the shaft. In addition, the thickness can be reduced. That is, when using a disk with a large unbalance or when rotating the disk at a low speed, the shaft shake caused by the clearance between the bearing and the shaft can be suppressed, and the accuracy of writing and reading can be improved. In addition, there is an effect that the thickness can be reduced.

  The invention according to claim 2 has an effect that cogging torque is reduced in addition to the effect of claim 1. As a result, it is possible to provide a disk drive motor with low vibration and noise and high rotational accuracy.

It is sectional drawing which shows the structure of the motor for disk drive devices by Embodiment 1 of this invention. It is a top view of the stator part of the motor for disk drive devices in Embodiment 1 of this invention. It is sectional drawing which shows the structure of the conventional motor for disk drive devices. It is a top view of the core of the conventional motor for disk drive devices.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

FIG. 1 shows a cross-sectional view of a disk drive motor according to Embodiment 1 of the present invention. In FIG. 1, a rotor part is a rotor frame 2 in which a turntable part and a yoke part are integrally formed by pressing or the like, and a disk holding mechanism. 5, a rotor magnet 3, a shaft 1, a TT cushion 4 for disc slip prevention, and a retaining member 13 which is a molded part of a metal material having a spring property. The disc holding mechanism 5 is a turntable portion by a spring force. In addition, it has a function of pressing and supporting the disk. The stator part is a molded part made of sintered metal or the like, and is wound with a stator winding 8 via a bearing 9 impregnated with oil, a housing 10 containing the bearing 9, and an insulator 7 as an insulator on the core 6. And a substrate 11 for electrically connecting terminals of the stator winding 8 and a metal plate 12. The shaft 1 of the rotor portion is inserted into the bearing 9 of the stator portion, and the rotor portion is rotatably supported with the inner peripheral surface of the rotor magnet 3 and the core 6 facing each other. The housing 10 and the substrate 11 are fixed to the plate 12. An engaged portion 14 is formed radially outward at the end of the housing 10 facing the rotor frame 2 and engages with a retaining member 13 to prevent the rotor portion from coming out of the stator portion. It constitutes a stop. A disk drive motor is constituted by the rotor part and the stator part. In the space between the stator winding 8 of the core 6 around which the stator winding 8 is wound and the housing 10 holding the bearing 9, the rotor comprising the engaged portion 14 and the retaining member 13 is prevented from coming off. Since the bearing 9 and the retaining stopper are not stacked in the height direction, the thickness can be reduced.

The above is the same configuration as the conventional disk drive device motor described in Patent Document 1 shown in FIG. A configuration that is a feature of the present invention, which is different from FIG. First, the core 6 uses a core in which the width of the core salient pole (the salient pole angle) is unevenly formed between the right half and the left half of the core as shown in FIG. The thickness is reduced and the height is reduced. Accordingly, since the core thickness is small and the facing area between the core 6 and the rotor magnet 3 is small, the radial urging force generated by the left-right imbalance of the attractive force acting between the core 6 and the rotor magnet 3 is small. . Therefore, the plate 12 is formed of a magnetic material, and a notch 12a is formed in a part of the plate 12 facing the end surface of the rotor magnet 3. The notch 12a is formed at a position facing the end face of the rotor magnet 3 and on the side where the salient pole angle of the core 6 is small (angle β side in FIG. 2) as shown in FIG. . By configuring as described above, the magnetic attractive force generated between the end surface of the rotor magnet 3 and the plate 12 is lost at the position of the notch 12a, so that the rotor part is unbalanced and the rotor part is opposite to the notch 12a. A pressing force is generated in the radial direction of the side. The radial pressing force is a direction in which the radial core salient pole width (salient pole angle) is large due to the left-right imbalance of the attractive force acting between the core 6 and the rotor magnet 3 (angle α in FIG. 2). The direction is the same as the force urging the side. Therefore, a lack of biasing force caused by the left / right imbalance of the attraction force acting between the core 6 and the rotor magnet 3 is caused by a pressing force caused by the imbalance of the magnetic attraction force generated between the end face of the rotor magnet 3 and the plate 12. Can be supplemented with.

  According to such a configuration, due to the radial pressing force generated between the rotor part and the stator part, when using a disk with a large unbalance or when rotating the disk at a low speed, it is caused by the clearance between the bearing and the shaft. It is possible to reduce the thickness of the motor at the same time while suppressing the shaft run-out and improving the writing / reading accuracy.

For the disk drive device according to the second embodiment of the present invention, in addition to the configuration of the first embodiment, the number of salient poles of the core 6 is 6n, the number of magnetic poles of the rotor magnet 3 is 8n, (n is Positive integer)
By setting the angle α−β = 15 ° / n, the two cogging torques having different phases by 180 ° are combined, and the cogging torques cancel each other and the cogging torque is reduced.

  According to such a configuration, in addition to the effect of the first embodiment, the cogging torque can be reduced. As a result, it is possible to provide a disk drive motor with low vibration and noise and high rotational accuracy.

  In the above-described embodiment, the rotor comprising the engaged portion 14 and the retaining member 13 is prevented from coming off in the space between the inner diameter side of the stator winding 8 of the core 6 and the housing 10 holding the bearing 9. However, as long as the thinning of the disk drive motor is not hindered, the other present invention can provide the same effect of the present invention.

The motor according to the present invention cuts out a part of the plate and the force that biases the rotor portion generated in one direction of the radial direction due to the attraction force acting between the core and the rotor magnet being imbalanced on the left and right. The force that presses the rotor part in the radial direction in combination with the force that biases the rotor part generated in an imbalance on the left and right in one direction in the radial direction due to the attraction force acting between the plate and the end surface of the rotor magnet Can be bigger. With this configuration, it is possible to compensate for the force that presses the rotor portion in the radial direction, which is insufficient when reducing the thickness of the core by reducing the thickness of the core. Therefore, the shaft runout and cogging torque caused by the clearance between the bearing and the shaft can be compensated. A reduction in thickness and a reduction in thickness can be achieved.
When using a disk with a large unbalance or when rotating the disk at a low speed, the shaft runout caused by the clearance between the bearing and the shaft can be suppressed, the writing / reading accuracy can be improved, and the thickness can be reduced at the same time. It is effective as a disk drive motor used in personal computers and AV equipment.

DESCRIPTION OF SYMBOLS 1,31 Shaft 2,32 Rotor frame 3,33 Rotor magnet 4,34 TT cushion 5,35 Disc holding mechanism 6,36,46 Core 7,37 Insulator 8,38 Stator winding 9,39 Bearing 10,40 Housing 11 , 41 Substrate 12, 42 Plate 12a Notch portion 13, 43 Retaining member 14, 44 Engaged portion

Claims (2)

A rotor frame, a shaft fixed to the center of the rotor frame, a disk holding mechanism for pressing and supporting the disk, a rotor portion having a rotor magnet fixed to the inner peripheral surface of the rotor frame, a bearing, and a housing containing the bearing And a stator assembly comprising a winding assembly configured by winding a stator winding through an insulating material on a core, a substrate electrically connecting a terminal of the stator winding, and a metal plate, The shaft of the rotor portion is inserted into the bearing of the stator portion, the rotor portion is rotatably supported with the inner peripheral surface of the rotor magnet facing the core, and the housing and the substrate are attached to the plate. In the fixed disk drive motor, the plate is made of a magnetic material, and the core has a core salient pole whose width is the right half of the core. And the left half are formed unevenly, and a notch is formed on the side of the plate facing the end face of the rotor magnet and on the side where the salient pole of the core is small. Disk drive motor. The core has salient poles with 6n poles, the rotor magnet is magnetized with 8n poles at an equiangular pitch, and (n is a positive integer) the width of the core salient poles is 15 in the right half and the left half of the core. The disk drive motor according to claim 1, wherein the motor is changed in a range of 5% before and after / n °.

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