JP5037433B2 - Disk drive - Google Patents

Description

  The present invention relates to a disk drive device.

  As devices for recording and reproducing digital data, magnetic disk drive devices such as hard disk drives, and optical disk drive devices such as CD (Compact Disc) devices and DVD (Digital Versatile Disc) devices are known. Among them, the use of hard disk drives is expanding with the miniaturization and thinning.

The hard disk drive includes a magnetic recording disk that is rotationally driven by a spindle motor, and a magnetic head that swings on the magnetic recording disk. The drive current generated by the control board of the hard disk drive is supplied from the control board to the spindle motor via the connector and the flexible board.
JP-A-4-276375 JP-A-6-45718 JP-A-8-106761 JP-A-11-308835

In such a hard disk drive, the present inventor has recognized the following problems.
When the spindle motor is started and at steady rotation, a drive current that periodically repeats commutation is supplied. This current is about 1 to 2 A at start-up and about 0.3 to 1 A at steady rotation, which is relatively high, and the ripple accompanying commutation is a magnitude that cannot be ignored. Therefore, a relatively large AC noise magnetic field is generated around the drive wiring by this drive current. If a large jump noise to the magnetic head is generated by the noise magnetic field, it may cause a recording / reproducing error.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a disk drive device in which jump noise due to drive current is reduced.

  One embodiment of the present invention relates to a disk drive device. This disk drive device has a base member having a mounting area of a motor for rotationally driving a recording disk on one side and a reference point in the area corresponding to the mounting area on the other side of the base member. Connected to the main board with a path that transmits power to the motor, and the power supply terminal provided on the path of the main board and the drive terminal of the motor through the opening of the base member. A conducting member that acts on the recording disk, and a head moving mechanism that moves the reproducing head within a movable range on at least the surface of the recording disk. The angle formed by the first auxiliary line perpendicular to the rotating shaft of the motor from the reproducing head and the second auxiliary line perpendicular to the rotating shaft from the power supply terminal is any position within the movable range of the reproducing head. Even if it exists, it is comprised so that it may be 90 degrees or more and 180 degrees or less.

  According to this aspect, the main board is mounted on the other surface of the base member in an angle range of 180 degrees or less when viewed from the reference point in the area corresponding to the mounting area. Therefore, the area of the main substrate is limited because it covers only a part of the base member rather than the entire surface of the base member. According to this aspect, the angle formed by the first auxiliary line perpendicular to the rotation axis of the motor from the reproduction head and the second auxiliary line perpendicular to the rotation axis from the power supply terminal is movable in the reproduction head. At any position within the range, the angle is 90 degrees or more and 180 degrees or less. Therefore, the distance between the conducting member through which the drive current flows and the reproducing head can be set to some extent in the in-plane direction of the base member.

  Note that any combination of the above-described constituent elements, and those obtained by replacing the constituent elements and expressions of the present invention with each other among methods, apparatuses, systems, etc. are also effective as an aspect of the present invention.

  ADVANTAGE OF THE INVENTION According to this invention, the disk drive device which reduced the jump noise by drive current can be provided.

  The embodiment of the present invention is suitably used for a magnetic disk drive device such as a hard disk drive, or an optical disk drive device such as a CD device or a DVD device. Hereinafter, the hard disk drive according to the embodiment will be described. In this hard disk drive, the drive current path is arranged at a distance from the magnetic head in the in-plane direction of the base plate. This reduces noise jumping into the magnetic head.

  In the following, the same or equivalent components and members shown in each drawing will be denoted by the same reference numerals, and repeated description will be omitted as appropriate. In addition, the dimensions of the members in each drawing are appropriately enlarged or reduced for easy understanding. In the drawings, some of the members that are not important for describing the embodiment of the present invention are omitted.

FIG. 1 is an exploded perspective view of a hard disk drive 200 according to the embodiment. The hard disk drive 200 includes an upper lid 170, a base plate 100, and a control board 160. The hard disk drive 200 is, for example, a 3.5-inch hard disk drive, and has a long side of about 14.7 cm and a short side of about 10.1 cm. A brushless motor 110 and a swing mechanism 140 are placed on the upper surface of the base plate 100. The brushless motor 110 holds the magnetic recording disk 120 and rotates it. Here, it is assumed that the upper surface of the base plate 100 is a surface on which the magnetic recording disk 120 is mounted.
The upper lid 170 is attached to the upper surface of the base plate 100 with screws or the like sandwiching a gasket (not shown), and seals the upper surface side of the base plate 100. This is to protect the magnetic recording disk 120 and the swing mechanism 140 mounted on the base plate 100 from dust and the like from the outside.

  A control board 160 is fixed to the lower surface of the base plate 100 by screws or the like. On the control board 160, a drive current to the brushless motor 110 is generated based on a power supply voltage and a control signal supplied from the outside, and a data signal read by the magnetic head is processed. The control board 160 is provided with an interface 162, through which a power supply voltage, a control signal, data to be recorded, and the like are supplied to the hard disk drive 200, and data read from the magnetic recording disk 120 is sent to the outside.

FIG. 2 is a top view of the base plate 100 of FIG. On the upper surface of the base plate 100, a brushless motor 110, an arm bearing 144, and a voice coil motor 146 are placed. A recess (not shown) into which the brushless motor 110 is placed on the upper surface of the base plate 100 is formed.
The brushless motor 110 is, for example, a spindle motor, and in particular, a 12-slot 8-pole magnetized spindle motor. The brushless motor 110 rotates the magnetic recording disk 120. The brushless motor 110 is driven by a three-phase drive current including a U phase, a V phase, and a W phase. The brushless motor 110 is placed on a line segment AA that bisects the short side in the short direction of the base plate 100. In the longitudinal direction, a sufficient clearance is provided between the wall surface 32 corresponding to one short side 30 of the base plate 100 and the magnetic recording disk 120, and the base plate 100 is disposed close to the one short side 30.

  The arm bearing 144 supports the swing arm 142 in a swingable manner. The voice coil motor 146 swings the swing arm 142 in accordance with external control data. The swing mechanism 140 of FIG. 1 includes a swing arm 142, an arm bearing 144, and a voice coil motor 146.

  A magnetic head 130 is attached to the tip of the swing arm 142. When the hard disk drive 200 is in an operating state, the magnetic head 130 moves within the movable range CD on the surface of the magnetic recording disk 120 as the swing arm 142 swings, and reads and writes data. Here, point C is a point corresponding to the inner periphery of the magnetic recording disk 120, and point D is a point corresponding to the outer periphery of the magnetic recording disk 120. The swing arm 142 may move to a retreat position provided beside the magnetic recording disk 120 when the hard disk drive 200 is in a stopped state. The magnetic head 130 may use, for example, a TMR (Tunneling Magneto Resistance) element as its reading element.

  FIG. 3 is a bottom view of the base plate 100 of FIG. On the lower surface of the base plate 100, a rib 102, a convex portion 104, and a screw receiver 108 are formed. A conductive member 150 is attached to the lower surface of the base plate 100. The rib 102 is a beam formed in a spider web shape on the lower surface of the base plate 100 around the rotation center E of the brushless motor 110, and is formed in an angle range of about 220 degrees when viewed from the rotation center E. The rib 102 is substantially line symmetrical with respect to the line segment AA and is formed on the short side 30 side of the base plate 100 close to the brushless motor 110. The rib 102 increases the rigidity of the base plate 100. The convex portion 104 is a portion where a part of the lower surface of the base plate 100 is raised in a columnar shape corresponding to the above-described concave portion on which the brushless motor 110 is placed.

  The conductive member 150 includes a flexible substrate 152, an insulating sheet 154, and a connector 156. In FIG. 3, the wiring in the flexible substrate 152 is omitted. A conductive wire (not shown) from a drive terminal (not shown) of the brushless motor 110 is connected to one end 42 of the flexible substrate 152. In order to protect against external electrical contact, the connecting portion is covered with an insulating sheet 154. A connector 156 is connected to the other end 44 of the flexible substrate 152.

  A line segment HF is defined by defining a foot of a line segment perpendicular to the rotation axis of the brushless motor 110 from the center of gravity H of the connector 156 as a point F. Further, a line segment JI is defined by defining a leg of a line segment perpendicular to the rotation axis of the brushless motor 110 from the center of gravity J of the magnetic head 130 as a point I. Within the movable range CD of the magnetic head 130, when the magnetic head 130 is at point C, the angle θ formed by the line segment HF and the line segment JI is minimized, and the magnetic head 130 and the conducting member are set so that the angle is 90 degrees. 150 is arranged. The rotation center E, point F, and point I are on the rotation axis of the brushless motor 110, and the rotation axis is perpendicular to the lower surface of the base plate 100, so that they are displayed in an overlapping manner in FIG.

  An opening 106 is provided on the top surface of the convex portion 104 in order to draw out the conductive wire from the drive terminal of the brushless motor 110 to the bottom surface of the base plate 100. The opening 106 is positioned so that the point where the center G is projected onto the lower surface of the base plate 100 is on the line segment where the line segment HF is projected onto the lower surface. Therefore, regardless of the position of the magnetic head 130 in the movable range CD, the length of the line segment JH is longer than the length of the line segment JG. That is, the distance from the magnetic head 130 to the connector 156 is larger than the distance from the magnetic head 130 to the opening 106.

  FIG. 4 is an enlarged view around the conductive member 150 of FIG. FIG. 4 shows a state where the insulating sheet 154 and the connector 156 are removed. The flexible substrate 152 has a motor side pad connected to the brushless motor 110 at one end, and a connector side pad connected to the connector 156 and an inspection pad provided along with the connector side pad at the other end. More specifically, the flexible substrate 152 has a first motor side pad 10a, a second motor side pad 10b, a third motor side pad 10c, and a fourth motor side pad 10d at one end thereof. At the other end, the first connector side pad 12a, the second connector side pad 12b, the third connector side pad 12c, the fourth connector side pad 12d, the first inspection pad 14a, the second inspection pad 14b, and the third inspection pad. 14c and a fourth inspection pad 14d. The first motor side pad 10a is connected to the first connector side pad 12a and the first inspection pad 14a. The same applies to the second motor side pad 10b to the fourth motor side pad 10d.

  Four lead wires extending from four drive terminals corresponding to the U-phase, V-phase, W-phase and midpoint potential used for exciting the three-phase coil of the brushless motor 110 are drawn from the opening 106, and the first motor side pad 10a to the fourth motor side pad 10d are connected by soldering. After this connection is completed, the opening 106 is sealed with a sealing resin such as an epoxy resin or a thermosetting resin. This is to keep the airtightness of the upper surface side of the base plate 100.

  The flexible substrate 152 is bent and attached to the top surface of the convex portion 104, the side surface (not shown) of the convex portion 104, and the lower surface of the base plate 100. The connector 156 is placed in the connector placement area 158 surrounded by the one-dot chain line. Pins of a connector 156 described later in FIG. 5 are connected to the first connector side pad 12a to the fourth connector side pad 12d. The first test pad 14a to the fourth test pad 14d are provided in the vicinity of the corresponding connector side pads. Each of the first test pad 14a to the fourth test pad 14d is exposed to the outside so that power can be supplied from the outside by a power supply jig or the like.

FIG. 5 is a perspective view showing the structure of the connector 156. The connector 156 includes a resin main body 20, a first connector pin 16a, a second connector pin 16b, a third connector pin 16c, and a fourth connector pin 16d. The first connector pin 16a to the fourth connector pin 16d are provided with a first mounting portion 18a to a fourth mounting portion 18d, respectively. In FIG. 5, since it is the shadow of the resin main body 20, the 1st attaching part 18a and the 2nd attaching part 18b are not shown.
The first attachment portion 18a to the fourth attachment portion 18d are attached to the first connector side pad 12a to the fourth connector side pad 12d in FIG. 4 by soldering, respectively. The first connector pin 16 a to the fourth connector pin 16 d are crimped to power supply terminals on the control board 160.

  FIG. 6 is a surface view of the control board 160 viewed from the base plate 100 side. That is, the surface of the control board 160 facing the lower surface of the base plate 100 (hereinafter referred to as the upper surface of the control board 160) is shown. A screw hole 164, a first power supply terminal 166a, a second power supply terminal 166b, a third power supply terminal 166c, and a fourth power supply terminal 166d are provided on the upper surface of the control board 160. The screw hole 164 penetrates the control board 160 and receives a screw for fastening the control board 160 to the base plate 100. The screw hole 164 corresponds to the screw receiver 108 of FIG.

  Drive currents corresponding to the U-phase, V-phase, and W-phase are supplied to three of the first power supply terminal 166a to the fourth power supply terminal 166d through wiring on the control board 160. The remaining terminals correspond to the midpoint potential of the three-phase coil of the brushless motor 110. The control board 160 is positioned and fixed with respect to the lower surface of the base plate 100 so that the first power supply terminal 166a to the fourth power supply terminal 166d are crimped to the first connector pin 16a to the fourth connector pin 16d of the connector 156, respectively. The

  FIG. 7 is a bottom view of the base plate 100 in a state where the control board 160 is fixed to the bottom surface of the base plate 100. The control board 160 is attached to a reference point, for example, an angle range of about 140 degrees when viewed from the rotation center E of the brushless motor 110 so as not to overlap the rib 102. The control board 160 is attached along the short side 34 whose one side is not on the rib 102 side of the base plate 100. A plurality of integrated circuits 22 such as an integrated circuit that controls driving of the brushless motor 110 and an integrated circuit that processes a signal from the magnetic head 130 are mounted on the lower surface of the control board 160. An interface 162 is attached to the one side.

The operation of the hard disk drive 200 configured as described above will be described.
When the hard disk drive 200 is in a stopped state, no drive current is supplied to the brushless motor 110, and the swing arm 142 is placed in its retracted position.
When the hard disk drive 200 is in an operating state, a three-phase drive current is supplied to the brushless motor 110, and the magnetic recording disk 120 is rotationally driven. At the same time, the voice coil motor 146 swings the swing arm 142, so that the magnetic head 130 moves back and forth on the movable range CD on the magnetic recording disk 120. The magnetic head 130 converts the magnetic data recorded on the magnetic recording disk 120 into an electric signal and transmits it to the control board 160, and the data sent from the control board 160 in the form of an electric signal is magnetically transferred onto the magnetic recording disk 120. Write as data. Here, the above-described three-phase drive current is a drive current that periodically repeats commutation.

  Thus, according to the hard disk drive 200 according to the present embodiment, the area of the control board 160 is limited because it covers not only the entire lower surface of the base plate 100 but only a part thereof. In addition, the distance between the conducting member 150 through which the drive current flows and the magnetic head 130 can be set in the in-plane direction of the base plate 100. Therefore, reducing the area of the control board 160 can reduce raw material costs, and at the same time, can reduce noise jumping into the magnetic head 130 due to drive current. Accordingly, even if the amplitude of the output signal from the magnetic head 130 is relatively reduced by increasing the recording density of the magnetic recording disk 120, more accurate reading is possible. Contributes to downsizing and downsizing. Furthermore, this contributes to the expansion of the operating temperature range of the device in which the hard disk drive 200 is mounted and the expansion of the operating vibration environment.

  Further, according to the hard disk drive 200 according to the present embodiment, the control board 160 is arranged in a region where the ribs 102 are not present on the lower surface of the base plate 100. Therefore, the control board 160 can be disposed closer to the lower surface of the base plate 100, which contributes to the thinning of the hard disk drive 200.

  In the hard disk drive 200 according to the present embodiment, the angle θ is 90 degrees or more. The reason will be described below. FIGS. 8A to 8E show simulation results for calculating the magnitude of noise jumping into the magnetic head 130 when the angle θ = 0 °, 30 °, 60 °, 90 °, and 120 °, respectively. It is a graph to show. The vertical axis represents the noise jumping into the magnetic head in units of mV. The horizontal axis is time. The magnitude of the jumping noise is 2.04 mV, 1.70 mV, 1.04 mV, 0.52 mV, and 0.468 mV in terms of the peak-to-peak voltage, respectively.

  The driving current used here is 1A at maximum, and the basic switching frequency of the motor is 2880 Hz. These are typical values when a hard disk drive equipped with a 12-slot 8-pole magnetized three-phase drive spindle motor is operating at 7200 rpm. In particular, the value of the basic switching frequency will be described. First, 3 (phase) × 8 (pole magnetization) = 24 times of switching while the spindle motor makes one rotation. Since 7200 rpm is 120 Hz, the basic switching frequency as a whole is 120 (Hz) × 24 (times) = 2880 Hz.

  The output voltage from the TMR element corresponding to the read magnetic data is about 1 mV in peak-to-peak voltage. For this output voltage, a margin of 40% is provided as a design experience value. Then, when the jumping noise is larger than 60% of the output voltage, the noise is mixed in the data signal. Therefore, the dive noise needs to be 1 mV × 0.6 = 0.6 mV or less. According to the hard disk drive 200 according to the present embodiment, a hard disk drive that satisfies the above requirements is realized. This is because the magnitude of noise is approximately 0.52 mV when the angle θ = 90 degrees from FIG.

  Moreover, according to the hard disk drive 200 according to the present embodiment, the control board 160 is attached to the lower surface of the base plate 100 so that one side thereof is along the short side 34 of the base plate 100. Therefore, the interface 162 can be attached to one side thereof, and connection with the outside is facilitated.

  Further, according to the hard disk drive 200 according to the present embodiment, the distance from the connector 156 to the magnetic head 130 is the distance from the opening 106 to the magnetic head 130 regardless of the position of the magnetic head 130 on the movable range CD. Bigger than. As a result, the arrangement of the flexible substrate 152 escapes from the magnetic head 130, and noise can be reduced more effectively.

  Further, according to the hard disk drive 200 according to the present embodiment, the inspection pad corresponding to the connector side pad is provided. Accordingly, the pin bending of the connector 156 at the test stage of the hard disk drive 200 is prevented, and the reliability of the power supply connection from the control board 160 to the brushless motor 110 is improved. Further, by adjusting the pressure of the power supply jig pressed against the inspection pad, it is possible to better control the vibration generated during servo writing. Accordingly, a more accurate servo write can be performed.

  The pin bending will be further described. The assembly process of the hard disk drive 200 includes a performance check process for checking the performance of the brushless motor 110 and a servo write signal writing process for writing servo tracks on the magnetic recording disk 120. In these steps, the brushless motor 110 must be rotated before attaching the control board 160 to the base plate 100. Therefore, conventionally, in these steps, a power supply jig is directly pressed against the connector in order to supply a drive current to the brushless motor 110. However, the pin of the connector 156 may be bent as a result of pressure contact with the power supply jig. Here, in the hard disk drive 200 according to the present embodiment, the power feeding jig is pressed against the inspection pad. This alleviates the problem of connector pin bending and contributes to improving the reliability of the power supply connection.

  The configuration and operation of the hard disk drive 200 according to the embodiment has been described above. This embodiment is an exemplification, and it is understood by those skilled in the art that various modifications can be made to combinations of the respective constituent elements, and such modifications are also within the scope of the present invention.

  In the embodiment, the case where the angle range in which the control board 160 is arranged is defined with the rotation center E as a reference point is described. However, the reference point is an arbitrary point on the top surface of the convex portion 104, for example, a point on the circumference thereof. Good for. In particular, the point on the circumference closest to the short side 30 may be used. In this case, since it is not necessary to provide the hole corresponding to the convex part 104 in the control board, the structure becomes simple and it is advantageous in manufacture. In particular, this is advantageous in that it is not necessary to cut a hole corresponding to the convex portion 104 in the control board manufacturing process.

  In the embodiment, the case of a 3.5-inch hard disk drive having a long side of about 14.7 cm and a short side of about 10.1 cm has been described, but the present invention is not limited to this. For example, in the case of a 3.5-inch magnetic recording disk, it may be a hard disk drive having a long side and a short side suitable for mounting it. Further, it may be a hard disk drive having a long side and a short side suitable for mounting a magnetic recording disk of 2.5 inches, 1.8 inches, or the like.

  In the embodiment, the case where one magnetic recording disk and one magnetic head are provided has been described. However, for example, a hard disk drive including a plurality of magnetic recording disks and a plurality of magnetic heads corresponding to the respective magnetic recording disks may be used.

  In the embodiment, the case where the brushless motor uses a three-phase driving current has been described. However, a brushless motor other than the three-phase motor may be used.

  In the embodiment, the case where the brushless motor 110 is mounted on the base plate 100 has been described. However, for example, the brushless motor may be formed on the base plate 100.

  Although the present invention has been described based on the embodiments, the embodiments merely show the principle and application of the present invention, and the embodiments are defined in the claims. Needless to say, many modifications and arrangements can be made without departing from the spirit of the present invention.

1 is an exploded perspective view of a hard disk drive according to an embodiment. FIG. 2 is a top view of a base plate included in the hard disk drive of FIG. 1. FIG. 2 is a bottom view of a base plate included in the hard disk drive of FIG. 1. FIG. 4 is an enlarged view around a conductive member attached to the lower surface of the base plate in FIG. 3. It is a perspective view which shows the structure of a connector. It is the surface view which looked at the control board from the baseplate side. It is a bottom view of the base plate in a state where the control board is fixed to the bottom surface of the base plate. FIGS. 8A to 8E are graphs showing the magnitude of the noise jumping into the magnetic head when the angle θ takes various values.

Explanation of symbols

  100 base plate, 110 brushless motor, 120 magnetic recording disk, 130 magnetic head, 140 swing mechanism, 142 swing arm, 150 conducting member, 160 control board, 162 interface, 170 upper lid, 200 hard disk drive, CD movable range, E rotation center.

Claims (8)

A base member having on one side a mounting area of a motor for rotationally driving the recording disk;
On the other surface of the base member, a main board that is mounted in an angle range of 180 degrees or less when viewed from a reference point in an area corresponding to the placement area, and has a path for transmitting electric power to the motor;
A conduction member that connects a power supply terminal provided on the path of the main substrate and a drive terminal of the motor via an opening of the base member;
A reproducing head acting on the recording disk;
A head moving mechanism for moving the reproducing head within a movable range on the surface of the recording disk,
The angle formed by the first auxiliary line perpendicular to the rotation axis of the motor from the reproduction head and the second auxiliary line perpendicular to the rotation axis from the power supply terminal is such that the reproduction head is movable. It is configured to be 90 degrees or more and 180 degrees or less at any position within the range ,
The reference point is a rotation center of the motor;
2. A disk drive device according to claim 1, wherein an integrated circuit for controlling driving of the motor and an integrated circuit for processing a signal from the reproducing head are mounted on the main substrate . The disk drive device according to claim 1, wherein one side of the main substrate is attached along one side of the base member. Regardless of the position of the reproducing head in the movable range, the movable range, the opening, and the distance from the reproducing head to the power supply terminal are larger than the distance from the reproducing head to the opening. , and disk drive device according to claim 1 or 2, characterized in that it decided the positional relationship of the power supply terminals. 4. The disk drive device according to claim 1, wherein the opening is located on a line of the second auxiliary line. 5. The conducting member has a motor side portion provided with a motor side pad connected to the drive terminal of the motor at one end, and a power supply side pad connected to the power supply terminal provided on the main substrate at the other end. 5. The flexible substrate comprising: a power supply side portion having an intermediate portion provided with a wiring for electrically connecting the motor side pad and the power supply side pad. 6. The disk drive described. The intermediate portion is bent in the direction of the rotation axis of the motor,
6. The disk drive device according to claim 5, wherein the motor side portion, the intermediate portion, and the power feeding side portion are attached to the other surface of the base member. The flexible substrate is formed so that a width dimension of the intermediate portion in a direction perpendicular to the second auxiliary line is smaller than a width dimension of the motor side portion in a direction perpendicular to the second auxiliary line. The disk drive device according to claim 5, wherein: The motor side pad is covered with a sealing resin that seals the opening;
The disk drive device according to claim 5, wherein the power feeding side portion is sandwiched between the main substrate and the base member.

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