JPH0684551U - Disk drive - Google Patents

Abstract

(57) [Summary] [Object] The present invention relates to a disk drive device for rotating a disk and detecting an index pulse for rotation control, and is thinned by eliminating a space for detecting an index pulse near a rotor part. The purpose is to When the rotor portion 37 is arranged inside the stator portion 40, a rotating body 33 is provided at one end of the spindle 32, and a magnetized portion 34 is formed on the outer peripheral side surface of the rotating body 33. Then, a detection unit 44 for detecting the magnetized portion 34 is provided on the printed wiring board 41 in the vicinity of the rotating body 33.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a disk drive device that rotates a disk and detects an index pulse for rotation control.

[0002]

[Prior art]

 In recent years, along with the trend toward lighter, thinner, shorter, and smaller disk devices, there has been a demand for thinner drive motors that rotate disks.

Conventionally, a DC brushless motor is generally used as a spindle motor for driving a disk, and a brushless motor used in a disk device is an outer rotor type in which a rotor is arranged outside a stator. , The inner rotor type in which the rotor is arranged inside the stator.

For the outer rotor type, for example, the present applicant has proposed that a magnet is provided on the rotor and a detection element for detecting the magnet is arranged in the vicinity of the rotor in order to detect an index pulse during disk rotation. It is disclosed in Japanese Utility Model Publication No. 60-135863.

On the other hand, the inner rotor type is thinner than the outer rotor type, and the index pulse is generally detected by detecting the rotation of the internal rotor.

Therefore, FIG. 3 shows a sectional view of a conventional inner rotor type spindle motor. The spindle motor 11 shown in FIG. 3 is for rotating and driving a 3.5-inch floppy disk, for example, and one end of the spindle 12 is attached with a rotating body 13 so as to partially project. Near the center, cores 14a and 14b, which are arranged in parallel and serve as rotors, are attached with a magnet 15 interposed therebetween.

A base 16 is arranged below the cores 14 a and 14 b, and a bearing 17 is interposed between the base 16 and the spindle 12. A coil 18 serving as a stator is arranged in the outer peripheral direction of the cores 14a and 14b, and the coil 18 is internally provided in a mounting member 19 formed by resin molding. Then, the mounting member 19 and the printed wiring board 20 are mounted, and at this time, the bearing 21 is interposed between the mounting member 19 and the spindle 12.

A magnet 22 is attached to the lower surface of the core 14 b, and a hall element 23 for detecting the magnet 22 is provided on the base 16 at a position facing the magnet 22.

In the spindle motor 11, when the coil 18 is excited to rotate the cores 14 a and 14 b, the rotating body 13 rotates, and the magnet 22 generated by the rotation of the cores 14 a and 14 b causes the hall element 23 to rotate. To detect the index pulse.

[0010]

[Problems to be solved by the device]

 However, the index pulse detection by the spindle motor 11 shown in FIG. 3 is performed by the magnet 22 on the core 14b and the Hall element 23 on the base 16, and a space for providing the magnet 22 and the Hall element 23 is required. Therefore, there is a problem that it is impossible to make the device thinner.

Therefore, the present invention has been made in view of the above problems, and an object of the present invention is to provide a disk drive device that eliminates a space for detecting an index pulse in the vicinity of a rotor and achieves a thin structure.

[0012]

[Means for Solving the Problems]

 In the disk drive device in which the rotor and the rotor on which the disk is placed are provided on the rotary shaft, and the stator is arranged in the outer peripheral direction of the rotor, the above-mentioned problem is obtained by magnetizing the rotor at a predetermined portion. And a detection unit for detecting the magnetized portion in the vicinity of the rotating body.

[0013]

[Action]

 As described above, the rotating body on which the disk is placed is provided with the magnetizing portion, and the detecting portion is provided near the rotating body. In this case, the detection of the index pulse during the rotation of the disc is performed by the detection unit detecting the magnetized portion of the rotating rotating body.

That is, since the magnetizing part and the detecting part for detecting the index pulse are not provided in the rotor part and the vicinity thereof, a space part for that is unnecessary, and the device can be made thin. Is.

[0015]

【Example】

 FIG. 1 is a sectional view showing the construction of an embodiment of the present invention. The disk drive device 31 of FIG. 1 is assumed to drive a 3.5-inch floppy disk as in the case of FIG. In this case, the 3.5-inch floppy disk is provided with a hub made of a magnetic member in which a hole for inserting the spindle and a hole for locating the drive pin are formed at the center of rotation, and the hub is exposed to expose the inside of the cartridge. It is stored in.

In the disk drive device 31 of FIG. 1, a disc-shaped rotating body 33 is fixed to one end of a spindle 32 as a rotating shaft with its tip protruding. The rotating body 33 is formed of a plastic magnet, and sucks and mounts the hub provided on the above-mentioned floppy disk. Although not shown, a drive pin that moves up and down by a spring or the like is formed on the rotating body 33, and the drive pin and the tip of the spindle 32 are respectively positioned in the holes formed in the hub when the floppy disk is attracted. It

Further, a magnetizing portion 34 is provided at a predetermined position on the outer peripheral side surface of the rotating body 33. The magnetization in the magnetizing unit 34 is formed of one pole of N pole or S pole, or two poles of N pole and S pole, and serves as an index magnet for detecting an index pulse. In this case, the magnetizing unit 34 can improve the positional accuracy with respect to the drive pin (not shown), and thus can improve the timing accuracy of the index pulse detection.

On the other hand, on the spindle 32, disk-shaped cores 36a and 36b sandwiching a magnet 35 are fixed in parallel to form a rotor portion 37. Then, a base 38 is disposed below and close to the core 36b, and a bearing 39 is interposed between the base 38 and the spindle 32.

Further, a stator portion 40 including a predetermined number of coils 40 a is arranged in the outer peripheral direction of the rotor portion 37. Then, the rotor portion 37 and the stator portion 40 are positioned on the mounting surface of the printed wiring board 41, the rotor 33 is disposed on the surface opposite to the mounting surface, and the stator portion is formed by the mounting member 42 formed by resin molding. 40 (coil 40a) is included and attached to the printed wiring board 41. At this time, the bearing 42 is interposed between the mounting member 41 and the spindle 32.

Further, at a predetermined position on the opposite side of the mounting surface of the printed wiring board 41, near the magnetized portion 34 of the rotating body 33, a detector 44 for detecting the magnetized portion 34 is used for soldering or the like. Is provided by The detection unit 44 is composed of, for example, a Hall element housed in a holder, and is cord-connected to the mounting surface of the printed wiring board 41.

When the disk drive device (spindle motor) 31 as described above chucks the floppy disk on the rotating body 33 and then supplies a current to the coil 40a, the rotor portion 37 of the cores 36a and 36b rotates. The rotating body 33 rotates via the spindle 32 to rotate the floppy disk.

At this time, the magnetized portion 34 of the rotating body 33 is detected as an index pulse by the hall element of the detector 44, for example. That is, the Hall element generates a Hall voltage by causing a control current to flow in a direction perpendicular to the magnetic flux from the magnetizing unit 34, and has been conventionally used because of its excellent response characteristics.

As described above, since the magnetizing unit 34 and the detecting unit 44 for detecting the index pulse are not provided in the vicinity of the rotor unit 37 but are arranged in the rotating body 33 and the vicinity thereof, By eliminating the space, the space of the rotor portion 37 and the stator portion 40 can be reduced, and the thickness can be reduced. Further, since the plastic magnet of the rotating body 33 is used as the index magnet of the magnetizing portion 34, the index magnet can be made unnecessary. Further, as described above, the positional accuracy between the magnetizing portion 34 and the drive pin is improved, and the accuracy of detection timing can be improved.

Next, FIG. 2 is a sectional view showing the configuration of another embodiment of the present invention. In the disk drive device (spindle motor) 31 of FIG. 2A, a magnetized portion 34 is formed on the back surface inside the rotating body 33, and a detection portion 44 is made to face the magnetized portion 34 and the printed wiring board 41 is provided. It is mounted on the top (a part of the mounting member 42 is removed), and other configurations are the same as those in FIG.

Further, in the disk drive device (spindle motor) 31 of FIG. 2B, a separate magnetizing section 34 is attached to the back surface of the rotating body 33, and the detecting section 44 is opposed to the magnetizing section 34. It is mounted on the printed wiring board 41 (a part of the mounting member 42 is removed), and other configurations are the same as those in FIG.

[0026]

[Effect of device]

 As described above, according to the present invention, the magnetized portion is provided at a predetermined portion of the rotating body, and the detecting portion for detecting the magnetized portion is provided in the vicinity of the rotating body to detect the index pulse near the rotor portion. It does not require a space and can be made thinner.

[Brief description of drawings]

FIG. 1 is a sectional view showing the configuration of an embodiment of the present invention.

FIG. 2 is a sectional view showing the construction of another embodiment of the present invention.

FIG. 3 is a sectional view of a conventional inner rotor type spindle motor.

[Explanation of symbols]

 31 disk drive device 32 spindle 33 rotating body 34 magnetizing part 37 rotor part 40 stator part 40a coil 41 printed wiring board 42 mounting member 44 detecting part

Claims (1)

[Scope of utility model registration request] 1. A disk drive device in which a rotor and a rotor on which a disk is mounted are provided on a rotating shaft, and a stator is arranged in the outer peripheral direction of the rotor, wherein a magnetizing unit is provided at a predetermined portion of the rotor. And a detector for detecting the magnetized portion in the vicinity of the rotating body.