JP2004319086A - Method and circuit for driving spindle motor for fdd, disk chucking method and fdd - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To surely chuck the disk hub of an FD (floppy disk) at the start of the rotation of a magnetic disk medium. <P>SOLUTION: In a method for driving and rotating the magnetic disk drive with a spindle motor used for an FDD (floppy disk drive) which records and reproduces data onto/from the magnetic disk medium of the FD that rotates either at a low-speed or a high-speed at the time of recording/reproduction, when the FD is made to rotate at a high-speed, the spindle motor is made to rotate at the low-speed slower than the high-speed at the time of starting to rotate the magnetic disk medium (step S3). After chucking the disk hub of the FD (yes of step S4), the spindle motor is made to rotate at the high-speed (step S5) to surely perform chucking. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a flexible disk drive (hereinafter, also referred to as FDD) for recording and reproducing data on a magnetic disk medium of a flexible disk (hereinafter, also referred to as FD) rotating at either low speed or high speed during recording and reproduction. In particular, the present invention relates to a method of driving a spindle motor to rotate and a method of chucking a disk so that the disk hub of the FD can be reliably chucked at the beginning of rotation of a magnetic disk medium.

  As is well known, the FDD is a device for recording and reproducing data on a magnetic disk medium of the FD inserted therein. In recent years, the capacity of the FD has been increased, and has a storage capacity of 128 Mbytes (hereinafter, referred to as large capacity) in contrast to a storage capacity of 1 M to 2 Mbytes (hereinafter, referred to as normal capacity). Things are being developed. Along with this, FDDs capable of recording and reproducing data on such a large-capacity FD magnetic disk medium have been developed.

  In the following, an FDD capable of recording and reproducing data only on a large-capacity FD magnetic disk medium is referred to as a high-density dedicated FDD, and an FDD capable of recording and reproducing data only on a normal-capacity FDD magnetic disk medium. It is usually referred to as a density-only FDD. Further, an FDD capable of recording and reproducing data on a magnetic disk medium of both a large capacity and a normal capacity FD will be referred to as a high-density / normal-density FDD. The high-density-dedicated FDD and the high-density / normal-density FDD are collectively referred to as a high-density FDD.

  One of the major mechanical differences between the normal-density type FDD and the high-density FDD is that the carriage holding the magnetic head is moved in a predetermined radial direction with respect to the FD inserted into the drive. (Radial direction of the magnetic disk medium). That is, while a stepping motor is used as a driving unit in a normal-density type FDD, a linear motor such as a voice coil motor (VCM) is used as a driving unit in a high-density FDD.

  Hereinafter, the voice coil motor used as the driving means of the high-density FDD will be described in some detail. The voice coil motor is disposed behind the carriage and wound around a drive shaft parallel to a predetermined radial direction, and a magnetic circuit for generating a magnetic field crossing a current flowing through the voice coil. Having. With such a configuration, by causing a current to flow through the voice coil in a direction crossing the magnetic field generated by the magnetic circuit, a driving force is generated in the direction in which the drive shaft extends based on the interaction between the current and the magnetic field. . With this driving force, the voice coil motor moves the carriage along a predetermined radial direction.

  Another major difference between the normal-density-only type FDD and the high-density-type FDD is the rotation speed of the spindle motor that rotates the inserted FDD magnetic disk medium. That is, in the normal-density-dedicated FDD, the FD to be inserted is limited to the normal-capacity FD. Therefore, the spindle motor for the FDD drives the inserted FD magnetic disk medium at a low speed of 300 rpm or 360 rpm. All you have to do is rotate. On the other hand, in the high-density type FDD, the FD to be inserted may be only the large-capacity FD or both the large-capacity FD and the normal capacity FD. Therefore, when the inserted FD has a large capacity FD, the high-density type FDD spindle motor must rotate the magnetic disk medium at a high speed of 3600 rpm, which is 12 to 10 times that of the normal capacity FD. No. Further, in the normal-density type FDD, the magnetic head contacts the magnetic disk medium of the normal capacity FD with a large pressure, whereas in the high-density FDD, the magnetic head contacts the magnetic disk medium of the inserted FD. Since the magnetic head contacts with a small pressure and rotates at a high speed of 3600 rpm in the case of a large capacity FD, the magnetic head flies above the magnetic disk medium.

  The difference between the normal capacity FD and the large capacity FD is that the normal capacity FD removes dust and the like on the magnetic disk medium in a case covering the magnetic disk medium in order to reliably perform chucking. While a thin sheet-like material that applies a load to a magnetic disk medium having a spring force, which is called a lifter, is provided, the large-capacity FD is not provided with such a lifter. The reason is that, as described above, since the large-capacity FD must rotate the magnetic disk medium at a high speed of 3600 rpm, it is not preferable to apply a load to the magnetic disk medium. In addition, the surface of the magnetic disk medium is rough in the normal capacity FD, whereas the surface of the magnetic disk medium is smooth in the large capacity FD.

  Therefore, the loss torque for the magnetic disk medium having the normal capacity FD is large in the normal density-dedicated FDD, whereas the loss torque for the magnetic disk medium having the large capacity FD is small in the high-density FDD.

  Conventionally, when recording / reproducing data to / from a large-capacity FD magnetic disk medium inserted by a high-density type FDD, the magnetic disk medium is rotated at a high speed immediately after startup by a spindle motor. ing.

  By the way, in order to rotate a large-capacity FD magnetic disk medium with a spindle motor, it is necessary to reliably chuck the large-capacity FD disk hub at the beginning of rotation of the magnetic disk medium.

  To be more specific, this disk hub is a disk-shaped bracket provided at the center opening of the lower case of the large-capacity FD, and has a disk center hole and a chucking hole (a disk-side driving slot). It is perforated and holds the magnetic disk medium housed in the upper case and the lower case. Therefore, in order to rotate the magnetic disk medium, the disk hub may be rotated by the spindle motor. On the other hand, the rotor of the spindle motor has a disk table that comes into mechanical contact with the disk hub when the magnetic disk medium rotates, and a spindle shaft that is provided vertically upright from the disk table and that penetrates into the disk center hole. And a chucking pin (drive roller) which is provided so as to be able to move up and down from the disk table and which is to be inserted through the chucking hole. That is, to reliably chuck the disk hub with respect to the disk table means that the chucking pin abuts on a radially outer corner of the chucking hole in a state where the chucking pin is loosely inserted into the chucking hole. That is.

  However, if the spindle motor is rotated at a high speed immediately after the start of rotation, as in the conventional spindle motor driving method, the disc table also rotates at a high speed, so that the chucking pin is loosely inserted into the chucking hole. Instead, it is buried in the disk table. Also, in the worst case, even if the chucking pin is once loosely penetrated into the chucking hole, the chucking pin breaks due to the impact between the chucking pin and the disk hub because the disk table rotates at a high speed. There is a risk of damage.

  Accordingly, an object of the present invention is to provide a spindle motor driving method and a disk chucking method that can more reliably chuck the disk hub of an FD at the beginning of rotation of a magnetic disk medium in view of the above-described conventional problems. To provide.

  According to the present invention, the magnetic disk medium is rotated by a spindle motor used in a flexible disk drive that records and reproduces data on a magnetic disk medium of a flexible disk that rotates at either a low speed or a high speed during recording and reproduction. A rotation driving method, wherein when the flexible disk is rotated at the high speed, a first step of rotating the spindle motor at the low speed lower than the high speed at the start of rotation of the magnetic disk medium And a second step of rotating the spindle motor at the high speed after chucking of the flexible disk with respect to the disk hub following the first step. Can be

  Further, according to the present invention, there is provided a disk chucking method of a flexible disk drive for performing recording and reproduction of data on a magnetic disk medium of a flexible disk which rotates at either a low speed or a high speed during recording and reproduction, In the case where the flexible disk is rotated at the high speed, a first step of rotating the spindle motor at the low speed lower than the high speed at the start of rotation of the magnetic disk medium; and And starting the spindle motor from the low speed to the high speed by a predetermined rapid acceleration after the flexible disk is chucked to the disk hub, wherein the predetermined rapid acceleration is performed. The chucking pin drives the table side in the disk table The chucking pin is moved radially outward along the inclined portion of the elongated hole so that the chucking pin abuts on a radially outer corner of the chucking hole of the disc hub, thereby forming a disc hub and the disc table. An FDD disc chucking method characterized by reliably performing chucking is obtained.

  In the present invention, at the start of the initial rotation, the spindle motor is rotated at a low speed, chucking is performed during this low speed, and after this chucking, the spindle motor is rotated at a high speed to perform chucking. Is definitely going. Therefore, the disk hub of the FD can be reliably chucked to the disk table at the initial stage of rotation of the magnetic disk medium.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  With reference to FIG. 2, a description will be given of a high-density FDD to which the spindle motor starting method and the disc chucking method according to the present invention are applied. The illustrated high-density FDD is a device that records and reproduces data on a large-capacity FD magnetic disk medium described later. The large-capacity FD is inserted into the high-density FDD from the direction indicated by the arrow A in FIG. The inserted large-capacity FD is held on a disk table 12 rotatably supported on the surface of the main frame 11 in a state where their central axes are aligned. The disk table 12 is driven to rotate by a spindle motor (to be described later) provided in a state embedded in a recess (to be described later) of the main frame 11, so that a large-capacity FD magnetic disk medium has a height of, for example, 3600 rpm. Spin at speed. A printed wiring board (not shown) on which a large number of electronic components are mounted is attached to the back surface of the main frame 11.

  The high-density FDD includes a magnetic head (not shown) for reading / writing data from / to a large-capacity FD magnetic disk medium. The magnetic head is held by a carriage 15 via a gimbal 14. The combination of the magnetic head, gimbal 14, carriage 15, voice coil 17 (described later), FPC (flexible printed circuit), scale, spring holder, and spring is called a carriage assembly. The carriage 15 is arranged on the surface of the main frame 11 so as to be separated from the main frame 11, and moves the magnetic head along a predetermined radial direction (the direction indicated by the arrow B in FIG. 2) with respect to the large-capacity flexible disk. Holding as possible.

  The carriage 15 is supported and guided at a lower end on both sides by a pair of guide bars 16 extending parallel to a predetermined radial direction B.

  The carriage 15 is driven in a predetermined radial direction B by a voice coil motor as described below. More specifically, the voice coil motor is disposed behind the carriage 15 and has a pair of voice coils 17 wound around a drive shaft parallel to a predetermined radial direction B, and intersects a current flowing through the voice coil 17. And a magnetic circuit 20 for generating a magnetic field. In the voice coil motor having such a configuration, a current is caused to flow through the voice coil 17 in a direction crossing the magnetic field generated by the magnetic circuit 20 so that the direction in which the drive shaft extends based on the interaction between the current and the magnetic field. A driving force is generated. With this driving force, the voice coil motor moves the carriage 15 in the predetermined radial direction B.

  Hereinafter, the spindle motor 100 used in the high-density FDD will be described with reference to FIG. 3A is a plan view, and FIG. 3B is a cross-sectional view of the rotor taken along line CC and the stator taken along line DD.

  The illustrated spindle motor 100 is of a type that is mounted not on the back surface of the main frame 11 but on the front surface of the main frame 11 (that is, on the surface on the side where an FD (not shown) is inserted). This is a type that is mounted in a state of being embedded in the concave portion 11a of the frame 11.

  The main frame 11 has a substantially cylindrical bearing metal 102 in the recess 11 a, and the bearing metal 102 stands upright at a substantially right angle to the main surface of the main frame 11. In the bearing metal 102, a spindle shaft 104 is rotatably supported on the main frame 11 via a ball bearing 106 in a state substantially perpendicular to the main surface of the main frame 11. The spindle shaft 104 functions as a rotation axis O of a magnetic disk medium of a large-capacity flexible disk (described later) inserted into a high-density type flexible disk drive. A disk-shaped disk table 12 is fitted on the upper end side of the spindle shaft 104, and the main surface of the disk table 12 extends in a direction orthogonal to the longitudinal direction of the spindle shaft 104 (the direction of the rotation axis O). .

  That is, the disk table 12 is rotatably supported on the surface of the main frame 11, and holds a large-capacity flexible disk inserted into a high-density type flexible disk drive in a state where the center axes (rotation axes O) of the disks are aligned. Hold.

  FIG. 4 shows a plan view of the large-capacity FD 40 as viewed from the back side. As shown in FIG. 4, the large-capacity FD 40 has a magnetic disk medium 41 as a magnetic recording medium and a case 42 that covers the magnetic disk medium 41. A circular opening 42a is opened at the center of the back side of the case 42. A disk hub (disk-shaped metal fitting) 43 for holding the magnetic disk medium 41 is loosely inserted through the circular opening 42a. In the center of the disk hub 43, a disk center hole 43a through which the spindle shaft 104 penetrates, and a chucking pin (drive roller) described later at a peripheral position shifted from the disk center hole 43a. A chucking hole (a disc-side driving elongated hole) 43b is formed.

  Returning to FIG. 3, the diameter of the disk table 12 is longer than the diameter of the disk hub 43 and shorter than the diameter of the circular opening 42a.

  The disk table 12 is provided with a table-side driving slot 12a at a position corresponding to the chucking hole (disk-side driving slot) 43b. The chucking pin (drive roller) 108 passes through the chucking hole 43b through the table-side driving slot 12a. The table-side driving slot 12a has an inclined portion 12b. The chucking pin 108 is attached to one end of a flexible arm 112 of a magnet case 110 attached to the lower surface of the disc table 12 via a holding portion 114 in a state of being urged upward through a table-side driving slot 12a. It is rotatably and freely mounted inside. Therefore, when a load is applied to the chucking pin 108 from above, the chucking pin 108 moves downward (sinks).

  The magnet case 110 is made of iron, is formed in a substantially tray shape by press working, and is bent downward at the outer periphery of the disk part 116 and the disk part 116 extending in parallel with the extending direction of the disk table 12. And an outer peripheral wall 118. A ring-shaped main magnet 120 is fixed to the inner side surface of the outer peripheral wall 118.

  In any case, the spindle shaft 104, the disk table 12, the chucking pin 108, the magnet case 110, the arm 112, the holding unit 114, and the main magnet 118 constitute a rotor of the spindle motor 100.

  The bearing metal 102 has a flange portion 102a, and a core 122 is fixed and mounted on the flange portion 102a by screws (not shown). The core 122 has a plurality of magnetic pole forming parts 122a extending radially at equal intervals. A coil 124 is wound around each magnetic pole forming part 122a. That is, an electromagnet (magnetic pole) is formed by the combination of the magnetic pole forming part 122a and the coil 124. The electromagnet is arranged to face the main magnet 120 while keeping a predetermined gap. Anyway, the core 122 and the coil 124 constitute a stator of the spindle motor 100.

  A substantially rectangular parallelepiped index detecting magnet 128 is fixed to an arbitrary position on the outer surface of the outer peripheral wall 118 of the magnet case 110. A printed board 126 is fixedly accommodated in the recess 11a of the main frame 11 by screws (not shown). A magnetic sensor (not shown) for detecting magnetism from the index detecting magnet 128 is arranged on the printed board 126.

  Further, the illustrated spindle motor 100 includes a balancer 130 as balance means. The balancer 130 is attached to the lower surface of the magnet case 110 on the opposite side of the chucking pin 108 with the spindle shaft 104 interposed therebetween. Thus, the center of gravity G of the rotor is made to coincide with the rotation axis O, and the rotor is balanced during rotation (particularly at high speed rotation).

  Referring to FIG. 4 again, case 42 of large-capacity FD 40 has a right-hand corner at the rear end in the insertion direction when viewed from the back side (a left-hand corner when viewed from the front side). A write protection hole (not shown) is provided. FIG. 4 shows a state in which the write protection hole is closed by the write protection tab 44. The write protection tab 44 is slidable in the insertion direction. By manually operating the tab, the write protection hole can be opened and closed. When the write-protection hole is closed by the write-protection tab 44, recording is enabled, and when the write-protection hole is opened, recording is disabled.

  The illustrated large-capacity FD 40 shows an example in which there are two types of storage capacities (for example, 128 Mbytes and 256 Mbytes). A large capacity identification detection hole 45 is formed near the write protection hole. The large-capacity identification detection hole 45 is for distinguishing the large-capacity FD 40 from the normal capacity FD. Further, a type identification detection hole 46 is selectively formed near the write protection hole together with the large-capacity identification detection hole 45. The type identification detection hole 46 is for identifying the type of the large-capacity FD 40, and the type of the large-capacity FD 40 can be identified depending on the presence or absence. For example, when the recording capacity is a large capacity FD of 128 Mbytes, the case 42 is not provided with the detection hole 46 for type identification, and when the recording capacity is a large capacity FD of 256 Mbytes, The type identification detection hole 46 may be formed.

  Returning to FIG. 2, in the high-density type FDD, a switch unit 50 is further mounted on a printed wiring board (not shown) provided on the back surface side of the main frame 11 at a left corner at the rear end in the insertion direction. ing. The switch unit 50 includes a push switch. The switch unit 50 is for detecting the write protection hole, the large capacity identification detection hole 45, and the type identification detection hole 46.

  More specifically, the switch unit 50 includes a write control switch 51, a large capacity identification switch 52, and a type identification switch 53. The write control switch 51 is a switch for detecting the open / close state of the write protection hole, and is provided at a position corresponding to the write protection hole. The large capacity identification switch 52 is a switch for identifying and detecting whether the inserted FD is the large capacity FD 40 or the normal capacity FD, and is provided at a position corresponding to the large capacity identification hole 45. The type identification switch 53 is a switch for detecting the presence or absence of the type identification detection hole 46, and is provided at a position corresponding to the type identification detection hole 46.

  Although not shown, a frequency generation pattern (hereinafter, abbreviated as FG pattern) for detecting the rotation speed of the spindle motor 100 is provided on the stator of the spindle motor 100. This FG pattern generates an FG signal having 60 pulses while the spindle shaft 104 of the spindle motor 100 makes one rotation. As is well known, 300 rpm is equal to 5 Hz / rev, and 3600 rpm is equal to 60 Hz / rev. Therefore, when the magnetic disk medium having the normal capacity FD is rotated by the spindle motor 100 at its specified rotation speed of 300 rpm, the FG pattern generates an FG signal of 300 Hz. Similarly, when the large-capacity FD 40 magnetic disk medium is being rotated by the spindle motor 100 at its specified rotational speed of 3600 rpm, the FG pattern generates an FG signal of 3600 Hz.

  FIG. 5 shows a control device 60 for controlling the driving of the spindle motor 100. The control device 60 receives a detection signal from the switch unit 50 and selectively outputs one of a low-speed selection signal SL and a high-speed selection signal SH as described later, and a 1 MHz clock frequency. And a spindle motor driver 63 for driving the spindle motor 100 based on the clock signal CLK, the FG signal, the low-speed selection signal SL, and the high-speed selection signal SH.

  The low speed selection signal SL is a signal for instructing to rotate the inserted FD magnetic disk medium at a low speed (300 rpm or 360 rpm), and the high speed selection signal SH is a signal for rotating the inserted FD magnetic disk medium. This is a signal for instructing rotation at a high speed (3600 rpm).

  The spindle motor driver 63 includes a phase locked loop (PLL) 631 and a drive transistor 632. Phase synchronization circuit 631 includes a frequency divider (not shown) that divides clock signal CLK. In response to the low speed selection signal SL, the frequency divider divides the clock signal CLK having a clock frequency of 1 MHz into a frequency-divided signal having a frequency of 300 Hz or 360 Hz. Similarly, in response to the high speed selection signal SH, the frequency divider divides the frequency of the clock signal CLK having a clock frequency of 1 MHz into a frequency divided signal having a frequency of 3600 Hz. The phase synchronization circuit 631 compares the FG signal with the frequency-divided signal and outputs a control signal indicating a phase difference between the signal and the frequency-divided signal. The drive transistor 632 drives the spindle motor 100 based on this control signal. That is, the spindle motor driver 63 drives the spindle motor 100 such that the frequency of the FG signal matches the frequency of the frequency-divided signal.

  A method of driving a spindle motor and a method of chucking a disk according to an embodiment of the present invention will be described with reference to FIG.

  First, the operation when the large capacity FD 40 is inserted into the high-density FDD to drive the large capacity FD 40 will be described. When the large-capacity FD 40 is inserted into the high-density type FDD, a disk holder (not shown) holding the large-capacity FD 40 descends, and applies a downward load to the large-capacity FD 40. Accordingly, the disk hub 43 of the large-capacity FD 40 is mechanically connected to the disk table 12 while the spindle shaft 104 of the spindle motor 100 is loosely inserted into the disk center hole 43a formed in the disk hub 43 of the large-capacity FD 40. The magnetic disk medium 41 comes into contact with and is held between the pair of upper and lower magnetic heads. At the same time, the switch unit 50 identifies and detects that the inserted FD is the large capacity FD 40, and the switch unit 50 sends a detection signal to the logic circuit 61 indicating that the large capacity FD 40 has been identified and detected.

  After determining from the detection signal that the inserted FD is a large-capacity FD (YES in step S1), the logic circuit 61 substitutes 1 as an initial value for a variable n (step S2). Then, the logic circuit 61 sends the low speed selection signal SL to the phase synchronization circuit 631 (step S3). In response to the low speed selection signal SL, the spindle motor driver 63 drives the spindle motor 100 to rotate at a low speed of 300 rpm or 360 rpm.

  Subsequently, the logic circuit 61 determines whether a predetermined time (for example, 500 msec) has elapsed (step S4). During this predetermined time, the disk table 12 is rotated at a low speed by the spindle motor 100, so that the chucking pin 108 of the spindle motor 100 is freely inserted into the chucking hole 43b formed in the disk hub 43 of the large capacity FD 40. Often done. In this case, the chucking pin 108 only penetrates into the chucking hole 43b, and at this time, the chucking between the disk hub 43 and the disk table 12 is not reliably performed. This is because, as described above, unlike the normal capacity FD, the large capacity FD 40 has no means such as a lifter for applying a load to the magnetic disk medium 41 in the case 42.

  After a predetermined time has elapsed (YES in step S4), the logic circuit 61 sends the high speed selection signal SH to the phase synchronization circuit 631 (step S5). In response to the high speed selection signal SH, the spindle motor driver 63 drives the spindle motor 100 to rotate at a high speed of 3600 rpm.

  After the spindle motor 100 responds to the high speed selection signal SH, in the process of changing from a low speed of 300 rpm or 360 rpm to a high speed of 3600 rpm by a predetermined rapid acceleration (for example, reaching 3600 rpm within 3 seconds), The table 12 rotates in the direction of arrow e in FIG. Accordingly, if the chucking pin 108 is loosely inserted into the chucking hole 43b, the chucking pin 108 extends radially outward of the disc table 12 along the inclined portion 12b of the table-side driving slot 12a. The chucking pin 108 moves and the chucking pin 108 abuts on a radially outer corner 43 c of the chucking hole 43 b of the disc hub 43. As a result, chucking between the disk hub 43 and the disk table 12 is reliably performed.

  In the present embodiment, the above-described processing is repeated two or more times to more reliably chuck the disk hub 43 and the disk table 12. That is, the logic circuit 61 determines whether the variable n is equal to N (N is an integer of 2 or more) (step S6). If the variable n is not equal to N, the logic circuit 61 increments the variable n by 1 (step S7), and returns to step S3.

  As described above, in the present embodiment, at the start of the initial rotation, the step of rotating the spindle motor 100 at a low speed and then rotating the spindle motor 100 to a high speed with a sharp acceleration force is repeated at least twice. Thus, the disk hub 43 of the large capacity FD 40 can be more reliably chucked at the beginning of rotation of the magnetic disk medium.

  When the inserted FD is the normal capacitance FD, it is identified and detected by the switch unit 50, and the switch unit 50 sends a detection signal indicating that the normal capacitance FD is identified and detected to the logic circuit 61.

  Based on this detection signal, the logic circuit 61 determines that the inserted FD is the normal capacitance FD (NO in step S1). Then, the logic circuit 61 sends the low speed selection signal SL to the phase synchronization circuit 631 (step S8). In response to the low speed selection signal SL, the spindle motor driver 63 drives the spindle motor 100 to rotate at a low speed of 300 rpm or 360 rpm. It should be noted here that the normal capacity FD has a lifter that applies a load to the magnetic disk medium in the case as described above, so that chucking can be performed even at a low speed of 300 rpm or 360 rpm. It is surely done.

  In the above embodiment, the speed of the spindle motor 100 is switched by switching the frequency division ratio of the phase synchronization circuit 631, but can also be switched by switching the clock frequency of the clock generator 62. Alternatively, two low-speed phase synchronizing circuits and high-speed phase synchronizing circuits may be prepared as the phase synchronizing circuits, and these may be switched and selected by a switch.

  Further, in the above-described embodiment, whether or not the predetermined time has elapsed is determined in step S4. Alternatively, it may be determined whether or not the disk table 12 has made one rotation.

5 is a flowchart illustrating a spindle motor driving method and a disc chucking method according to an embodiment of the present invention. 1 is a plan view showing a high-density flexible disk drive to which a spindle motor driving method and a disk chucking method according to the present invention are applied. 3A and 3B are views showing in detail a spindle motor used in the high-density type flexible disk drive shown in FIG. 2, wherein FIG. 2A is a plan view, FIG. 2B is a line CC along the rotor side, and line DD along the stator side. It is sectional drawing cut | disconnected by the line. FIG. 3 is a plan view of a large-capacity flexible disk accessed by the high-density flexible disk drive shown in FIG. 2 as viewed from the back side. FIG. 4 is a block diagram showing a control device for controlling the driving of the spindle motor shown in FIG. 3 together with a spindle motor and a switch unit.

Explanation of reference numerals

DESCRIPTION OF SYMBOLS 12 Disk table 12a Table side drive slot 12b Inclined part 40 Large capacity flexible disk 43 Disk hub 43a Disk center hole 43b Chucking hole 43c Corner 50 Switch unit 60 Control device 61 Logic circuit 62 Clock generator 63 Spindle motor driver 100 Spindle motor 104 Spindle shaft 108 Chucking pin

Claims (7)

There is a case where data is recorded / reproduced on a magnetic disk medium of a flexible disk rotating at a low speed during recording / reproduction, and a case where data is recorded / reproduced on / from a magnetic disk medium of a flexible disk rotating at a high speed. A method for rotating the magnetic disk medium by a spindle motor used for a flexible disk drive,
When rotating the flexible disk at the high speed, a first step of rotating a spindle motor at the low speed lower than the high speed at the start of rotation of the magnetic disk medium;
A second step of rotating the spindle motor at the high speed after the flexible disk is chucked with respect to a disk hub, following the first step.   The method according to claim 1, wherein the high speed is at least ten times the low speed.   3. The method of claim 2, wherein the high-speed rotation speed is 3600 rpm, and the low-speed rotation speed is 300 rpm or 360 rpm. 4.   The method according to claim 1, wherein in the second step, the speed is raised from the low speed to the high speed by a predetermined rapid acceleration. There is a case where data is recorded / reproduced on a magnetic disk medium of a flexible disk rotating at a low speed during recording / reproduction, and a case where data is recorded / reproduced on / from a magnetic disk medium of a flexible disk rotating at a high speed. A disk chucking method for a flexible disk drive,
When rotating the flexible disk at the high speed, a first step of rotating the spindle motor at the low speed lower than the high speed at the start of rotation of the magnetic disk medium;
A second step of starting the spindle motor from the low speed to the high speed by a predetermined rapid acceleration after the flexible disk is chucked to the disk hub, following the first step. ,
The predetermined rapid acceleration causes the chucking pin to move radially outward along the inclined portion of the table-side driving slot in the disk table, so that the chucking pin moves radially outward of the chucking hole of the disk hub. A disk chucking method for an FDD, characterized in that the disk hub and the disk table are reliably chucked by contact with the corners of the FDD. There is a case where data is recorded / reproduced on a magnetic disk medium of a flexible disk rotating at a low speed during recording / reproduction, and a case where data is recorded / reproduced on / from a magnetic disk medium of a flexible disk rotating at a high speed. In flexible disk drives,
When rotating the flexible disk at the high speed, at the start of rotation of the magnetic disk medium, rotation start means for rotating a spindle motor at the low speed lower than the high speed,
High-speed rotation means for rotating the spindle motor at the high speed after chucking of the flexible disk with respect to a disk hub following rotation activation by the rotation activation means. There is a case where data is recorded / reproduced on a magnetic disk medium of a flexible disk rotating at a low speed during recording / reproduction, and a case where data is recorded / reproduced on / from a magnetic disk medium of a flexible disk rotating at a high speed. A spindle motor drive circuit for a flexible disk drive, which rotationally drives the magnetic disk medium by a spindle motor used for a flexible disk drive,
When rotating the flexible disk at the high speed, at the start of rotation of the magnetic disk medium, a rotation start circuit that rotates a spindle motor at the low speed lower than the high speed,
A high-speed rotation circuit for rotating the spindle motor at the high speed after the flexible disk is chucked with respect to a disk hub following the rotation activation by the rotation activation circuit;

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