JPH0441443Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to a magnetic recording/reproducing device in which the stator yoke of a motor that rotates a magnetic disk is extended and also serves as a magnetic shield for an amplifier circuit section.

[Prior Art] Conventionally, as shown in FIG. 4, in a magnetic recording/reproducing device 80, a main body case 81 is integrally formed in a box shape with a metal member, and a flat portion 81a
A drive shaft 83 rotates the magnetic disk 82.
A motor 84 for rotationally driving the drive shaft 83 is provided, and a deceleration mechanism 85 for decelerating the rotation of the drive shaft 83 is provided.
Shafts 86, 87, 88, which rotatably support gears (not shown) of the gear train forming the
89 is fixed thereto, and a support shaft 92 that rotatably supports a head arm portion 91 supporting a magnetic head 90 is fixed to the tip end thereof.

A capstan 93 is attached to the rotation output portion of the speed reduction mechanism 85. One end of the steel belt 94 is fixed to the capstan 93, and the middle part is connected to a pulley 95 provided on the lower surface of the head arm 91 that supports the magnetic head 90.
After being folded back, the other end is fixed to a support portion 97 via a positioning pulley 96 provided on the main body case 81.

Rear end of head arm 91 and main body case 81
The head arm 91 is attached so that the magnetic head 90 supported at the tip thereof is positioned at the home position of the magnetic disk 82 by a spring 98 that is locked to a locking portion 99 provided at the head arm 91 . Forced.

Here, since the main body case 81 cannot be grounded because the magnetic recording/reproducing device 80 is incorporated into another device, the support shaft 9 of the head arm portion 90
2 is made of an insulating material to insulate the main body case 81 and the head arm part 91, and then the head arm part 9
1 is grounded.

A screw hole 100 for attaching to another device is provided in the side portion 81b of the main body case 81.

Further, on the back side of the flat portion 81a of the main body case 81, there is a PC board 104 on which a drive control circuit for the motor 84 is mounted, and a PC on which a signal circuit for recording and reproducing signals on the magnetic disk 82 is mounted.
A substrate 105 is disposed thereon, and an amplifier circuit section 106 of the signal circuit section that amplifies the signal from the magnetic head 90 is covered with a shield plate 107 to protect it from weak signals from the magnetic head 90. It is magnetically shielded to block noise such as motor noise.

With such a configuration, the magnetic recording/reproducing device 80 is screwed and incorporated into another device through a screw hole 100 provided in the side surface portion 81b of the main body case 81.

When the power of the entire device is turned on, the motor 84 is driven, the drive shaft 83 rotates, and the magnetic disk 82 rotates, and the rotation speed of the drive shaft 83 is reduced by the speed reduction mechanism 85. is transmitted to the rotation output section. When the rotary output section rotates, the steel belt 94 connects to the capstan 93.
Since the head arm portion 91 moves toward the outer circumference of the magnetic disk 82 due to the tension of the steel belt 94, a spiral recording/reproducing track is formed on the magnetic disk 82 by the magnetic head 90 attached to the tip. The signal from the magnetic head 84 is amplified by the amplifier circuit section 106 of the signal circuit section and output to other devices.

When the magnetic head 90 reaches the zero track position, the capstan 93 is released from the rotation of the drive shaft 83, the head arm 91 is urged by the spring 98 and returns to its original position, and the magnetic head 90 is positioned at the home position. Ru.

[Problems to be solved by the invention] As described above, it is necessary to incorporate the motor drive control circuit section and the signal circuit section together with the mechanical section into a small device. Furthermore, since the signal from the magnetic head 90 is weak, it must be shielded from motor noise generated by changes in magnetic flux as the motor 84 rotates, as well as other internal and external noise. Therefore, the magnetic head 90
The amplification circuit section 106 that amplifies the signal from the oscilloscope is covered with a shield plate 107 to provide magnetic shielding.

Therefore, the number of parts increases accordingly, and the work of incorporating the shield plate 107 into the miniaturized magnetic recording/reproducing device 80 is also added, which increases the number of work steps and increases the cost. It also became an obstacle.

[Means for solving the problem] In this invention, a PC board is placed opposite to a base board on which the motor, head arm, and power mechanism are attached, and the stator yoke of the motor is formed on this base board. At the same time, this stator yoke is extended to at least a position covering the amplifier circuit section of the base board so that it also serves as a magnetic shield plate for the amplifier circuit section, thereby reducing the number of parts and improving work efficiency. This is what I did.

[Function] A motor, a head arm, and a power mechanism for positioning the magnetic disk at its home position and forming tracks for recording and reproducing are attached to the base board, and the base board and the PC board are placed opposite each other. Arrange. Further, a stator yoke of the motor is formed on the base substrate, and this stator yoke is extended at least to a position covering the amplifier circuit section to be used as a magnetic shield plate for the amplifier circuit section. In this way, the amplifier circuit section is magnetically shielded by the portion extending from the stator yoke, and the amplifier circuit section is shielded from noise.

[Example] An example of this invention will be described in detail based on FIGS. 1 to 3.

In Figures 1 to 3, 1 is the main body case of the magnetic recording and reproducing device, which is composed of a frame 2 for attaching the magnetic recording and reproducing device to other equipment, and a base board 3 for attaching the mechanical part. ing.

The frame body 2 is formed into a box shape with an insulating material such as synthetic resin, and a gear mounting portion 4 having a shape corresponding to a gear train is provided transparently at approximately the center of the plane portion 2a. A gear frame 5 is provided upright, and magnetic disks 6 are provided around the plane portion 2a.
Ribs 7, 8, and 9 are erected for positioning in the height direction, front-rear direction, and left-right direction, and
The side surface portion 2b has a screw hole 10 that serves as a mounting portion 10 for attaching the magnetic recording/reproducing device to another device.
10... are provided.

A gear cover 11 fits into the gear frame 5 integrally provided on the frame body 2 and covers the upper surface of the gear mounting portion 4, and is provided on the gear frame 5 and the gear cover 11, respectively. Engaging portion 5a and engaged portion 11
It is removably engaged with a.

The base substrate 3 is made of a metal material with high magnetic permeability, such as iron, and is formed into a flat plate shape corresponding to the plane portion 2a of the frame 2, and has a gear train of the speed reduction mechanism 12 formed on its surface. Gears 13, 14, 15,
Shafts 17 and 1 rotatably support the shafts 16 and 16, respectively.
8, 19, 20, a support shaft 22 of the head arm portion 21, and a pulley 24 for positioning the steel belt 23 are fixed at predetermined positions, respectively.
Bosses 27, 27, etc. are provided on the back surface for screwing the PC board 26 on which the drive control circuit section 63 of the motor 25 and the signal circuit section are mounted, and the PC board 26 and the base board 3 are connected to each other. are arranged to face each other and are screwed to the boss 27 with a screw 28. Both the drive control circuit section 63 and the signal circuit section control the drive of the motor 25 and the magnetic head 32, respectively, based on commands from a central processing unit (hereinafter referred to as CPU) incorporated in another device. 6, the signal is recorded and played back.

The base board 3 and the PC board 26 are arranged to face each other, and the base board 3 is extended to a position that covers at least the amplifier circuit section 64 of the signal circuit section mounted on the PC board 26. .

Further, the base substrate 3 is provided with an opening 31 through which a bearing 30 of a drive shaft 29 which is rotationally driven by the motor 25 and rotates the magnetic disk 6 is fitted.

Therefore, the base board 3 is equipped with a motor 25, a head arm section 21 that supports the magnetic head 32, and a speed reduction mechanism 12 composed of a gear train, and provides power for converting the rotation of the drive shaft 29 into reciprocating motion of the head arm section 21. Mechanical parts such as the mechanism 33 are disposed, and the base board 3 is extended to a position covering an amplifier circuit section 64 mounted on the PC board 26.

A coil 34 of the motor 25 is provided on the PC board 26, and an insulating sheet 35 is attached between the coil 34 and the base board 3. Bearing section 30 rotatably supports drive shaft 29
is assembled into the bearing housing 36 and fixed with adhesive, and the upper end is attached to the bearing housing 36.
protrudes from the upper opening.

A flange portion 37 is provided at the upper end opening of the bearing housing 36.
is formed. A holder 38 that supports the magnetic disk 6 is fixed to the tip of the drive shaft 29 by a spring pin 39.

Here, the holder opening 38a formed in the frame body 2 and through which the holder 38 passes is inserted into the upper end of the bearing part 30 protruding from the bearing housing 36 (the opening 31 transparently provided in the base board 3). (the part that fits) is formed larger.

Because it is formed in this way, when replacing the rotor 41 of the motor 25 and other motor parts,
Conventionally, it was necessary to remove the mechanical part attached to the flat part 81a of the main body case 81, but in the case of this embodiment, the base board 3 and the PC
Since the motor part can be pulled out after separating from the board 26, parts replacement is easy.

Moreover, since the upper end of the bearing part 30 is pressed against the lower surface of the edge of the holder opening 38a provided through the frame body 2, the bearing part 30 is prevented from protruding when dropped.

The flange 37 of the bearing housing 36 is held between the base board 3 and the PC board 26, and the bearing housing 36 is attracted to the base board 3 by the rotor magnet 40 of the motor 25. On the other hand, since the base board 3 and the PC board 26 are fixed to each other by the boss 27 and the screws 28, there is no need to fix the bearing housing 36 to the base board 3 with screws or the like.

That is, the drive shaft 29 and the rotor 41 are prevented from coming off by the holder 38, the holder 38 is prevented from coming off by the bearing part 30, and the bearing part 30 is prevented from coming off by the collar part 37 of the bearing housing 36. There is.

In this way, the motor 25 is attached to the base board 3 via the bearing part 30, while the base board 3 is made of a metal member with high magnetic permeability and is mounted on the PC board 26. Since it is extended to the amplifier circuit section 64, the rotor 4
The portion of the base substrate 3 facing the motor 25 is used as a stator yoke of the motor 25, and the portion of the base substrate 3 facing the amplifier circuit section 64 is used as a shield plate of the amplifier circuit section 64. The amplifier circuit section 64 is magnetically shielded.

In this case, the magnetic flux is the iron core (N pole) of the coil 34
→ Base board 3 located opposite the coil 34 (becomes the stator yoke) → Iron core of the coil 34 (S pole)
A magnetic path is formed that passes through → the north pole of the rotor magnet 40 → the rotor yoke 41a → the south pole of the rotor magnet 40 → the iron core (north pole) of the coil 34.

The magnetic disk 6 is supported by a holder 38 and rotated by a drive shaft 29. The surface of the magnetic disk 6 includes a recording and reproducing area in which a large number of recording and reproducing tracks are formed in a spiral shape;
Provided at the center and outer periphery of the magnetic disk 6,
A zero track area (CSS area) in which no tracks are formed is provided.

The head arm section 21 is composed of a head arm 21a and a load arm 21b.A magnetic head 32 is attached to the tip of the head arm 21a, and the rear end is attached to a support shaft 22 fixed to the base board 3. The magnetic head 32 is attached to the magnetic head 32 at all times by a spring 42 which is rotatably attached and which is engaged with the rear end of the spring 42 and a engagement part 42a provided on the frame 2 made of an insulating material. is biased so that it is located at the home position of the magnetic disk 6.

Therefore, since the head arm portion 21 is insulated from the frame body 2, the support shaft 92 is surrounded with an insulating material and the main body case 8 is closed, as in the conventional case (FIG. 4).
1 and the head arm portion 91, the number of parts can be reduced, and the support shaft 22 can be made of either a conductive material or a conductive material.

In addition, since the head arm portion 21 is electrically connected to the frame body 2 by the spring 42, the base board 3 can be grounded, and when the magnetic recording/reproducing device is incorporated into another device, it can be connected to the frame 2. It is possible to perform stable recording and reproduction without being affected by noise from other devices, and to reduce failures caused by other devices.

On the other hand, the load arm 21b is connected to the head arm 21 by a spring 43 wound around a spring shaft 43a.
The magnetic disk 6 held between the load arm 21b and the load arm 21b is urged toward the magnetic head 32.

The reduction mechanism 12 reduces the rotational speed of the drive shaft 29, and the reduction mechanism 12 reduces the rotational speed of the drive shaft 29.
It is composed of a gear train consisting of gears 13, 14, 15, and 16 which are rotatably provided at the terminals 7, 18, 19, and 20, respectively, and a capstan 44 is fixed to the final stage and serves as a rotation output section. There is. The rotation output section and the support section 45 provided on the base board 3 are connected to the steel belt 2 through a pulley 24 for positioning the steel belt 23.
3 is mounted thereon, and constitutes a power mechanism 33 that converts the rotation of the drive shaft 29 into reciprocating motion of the head arm section 21 via the speed reduction mechanism 12.

That is, one end of the steel belt 23 formed of a metal member is fixed to a capstan 44, the middle part is folded back by a pulley 46 fixed to the lower surface of the head arm 21a, and the other end is fixed to the base board 3. Positioning pulley 2 installed upright
As the steel belt 23 is wound around the capstan 44, the head arm 21 resists the bias of the spring 42 due to the tension of the steel belt 23. It is configured to move in the radial direction of the magnetic disk 6.

The support part 45 is composed of an adjustment table 49 fixed to the base board 3 with screws 48 and a U-shaped adjustment leaf spring 47 whose one end is fixed to the adjustment table 49 with a screw 50. . Reference numeral 51 denotes an adjustment screw, which is attached to the adjustment table 49 so as to be freely retractable.The tip portion is in contact with the adjustment leaf spring 47.
The position of the magnetic head 32 is adjusted by pressing the steel belt 23 to adjust the tension of the steel belt 23.

At the lower end of the capstan 44 of the rotation output section,
A stopper spring 52 formed of an elastic member is fixed, and on the upper surface of the final stage gear 16 of the speed reduction mechanism 12 which is rotatably supported by the shaft 20,
A protrusion 53 is provided in a protruding manner.

The stopper spring 52 has a cut-and-raised portion 5 at its tip.
4 and an inclined piece 55 are integrally formed facing each other, the cut-and-raised part 54 engages with the projection part 53, and the inclined piece 55 is provided at a position where the gear cover 11 corresponds to the gear 16. When the protrusion 56 is engaged with the inclined protrusion 56 and the protrusion 56 is overcome, the engagement between the cut and raised portion 54 and the protrusion 53 is released.

Therefore, the stopper spring 52, the protrusion 53, the raised part 54, the inclined piece 55, and the inclined protrusion 56 constitute a clutch mechanism. It is provided so that it can be freely engaged and detached via a mechanism. That is, when the gear 16 rotates, the cut and raised portion 54 of the stopper spring 52 is engaged with the protrusion 53 and rotates together with the capstan 44, and when the inclined piece 55 climbs over the inclined protrusion 56, the stopper spring 52 is elastically deformed. Then, the engagement between the protruding portion 53 and the cut-and-raised portion 54 is released. When this engagement is released, the head arm portion 21 is urged by the spring 42 and returns toward the center of the magnetic disk 6, and at the same time, the stopper spring 52 returns to its original position together with the capstan 44.

Therefore, the protrusions 53 and the inclined protrusions 56 are provided at positions corresponding to the boundaries between the zero track area and the recording/reproducing area formed at the center and outer circumference of the magnetic disk 6, respectively. I'm positioning Shion.

Reference numeral 57 denotes a switch for confirming rewriting of the magnetic disk 6, and is attached to a rib 58 erected on the frame 2.

Reference numeral 59 denotes a lid, which covers the top surface of the main body case 1, and is rotatably attached to the main body case 1 with screws 60, and on the back surface of the lid 59,
A locking portion 61 that locks the load arm 21b is provided, and when the lid body 59 is rotated, the locking portion 61 lifts the load arm 21b and creates a magnetic gap between the head arm 21a and the load arm 21b. The disc 6 is configured to be insertable. 62 is a stopper of the head arm portion 21.

Next, the operation will be explained.

When the lid body 59 is rotated about the screw 60,
Since the load arm 21b is locked by the locking portion 61 and lifted, the magnetic disk 6 is inserted into the insertion slot 59.
When inserted from the position a, the magnetic disk 6 is held between the head arm 21a and the load arm 21b, and is mounted at the position defined by the ribs 7, 8, and 9.

When the magnetic disk 6 is attached, the switch 57
is in the on state, and the head arm section 21 is biased by the spring 42, so that the magnetic head 32 supported at the tip end of the head arm section 21 moves toward the magnetic disk 6.
is positioned at its home position.

Here, when the power of the entire apparatus (not shown) is turned on, a command from the CPU is input to the drive control circuit 63, the motor 25 is driven, the drive shaft 29 is rotated, and the magnetic disk 6 is rotated. magnetic disk 6
When a recording/reproduction command is input from the CPU to the magnetic disk 6 while the drive shaft 29 is rotating, the rotation of the drive shaft 29 is transmitted to the deceleration mechanism 12, the rotation speed is reduced and transmitted to the rotation output section, and the rotation output section As the steel belt 23 rotates, the steel belt 23 is wound around the capstan 44. As the steel belt 23 is wound around the capstan 44, the head arm portion 21 rotates along the radial direction from the center of the magnetic disk 6 to the outer periphery due to the tension of the steel belt 23, using the support shaft 22 as a fulcrum. The magnetic head 32 moves toward the outer circumference of the magnetic disk 6 while recording and reproducing information on the recording and reproducing tracks 6 on the magnetic disk.

In this way, the signal from the magnetic disk 6 picked up by the magnetic head 32 is amplified by the amplifier circuit section 64 and output to other devices.
At this time, since the amplifier circuit section 64 is magnetically shielded by the base substrate 3, the weak signal from the magnetic head 32 is shielded from noise.

During this time, the stopper spring 52 is rotated together with the gear 16 and the capstan 44, with the raised portion 54 being engaged with the protrusion 53.

When the magnetic head 32 reaches the zero track position of the magnetic disk 6, a sensor (not shown) detects this position and inputs it to the CPU, which outputs a command to stop the motor 25 to the drive control circuit 63.
At the same time as the rotation of the motor 25 is stopped, the inclined piece 55 of the stopper spring 52 climbs over the inclined protrusion 56, so the cut and raised part 54 is released from the engagement with the protrusion part 53, and the stopper spring 52, together with the capstan 44, moves in the opposite direction. As the magnetic head 32 rotates and returns to its original position, the head arm 21 is released from the tension of the steel belt 23 and is urged by the spring 42 to return to its original position, and the magnetic head 32 is positioned at its home position. .

[Effects of the invention] In this invention, a PC board is arranged to face a base board on which a motor, a head arm portion, and a power mechanism are attached, and a stator yoke of the motor is formed on this base board. The stator yoke is extended to a position that covers the amplifier circuit mounted on the PC board, and this amplifier circuit is magnetically shielded, so it can be used as the motor's stator yoke and the shield plate for the amplifier circuit. Therefore, there is no need to install a stator yoke for the motor or a shield plate for the amplifier circuit as in the conventional case, reducing the number of parts and improving work efficiency. The overall structure can be made smaller and thinner.

[Brief explanation of the drawing]

Figures 1 to 3 show examples of this invention; Figure 1 is a cross-sectional view, Figure 2 is a developed view, Figure 3 is a plan view, and Figure 4 is a developed view of a conventional example. be. 1... Magnetic recording and reproducing device, 2... Frame, 3...
Base board, 6...Magnetic disk, 12...Deceleration mechanism, 21...Head arm section, 25...Motor, 26...PC board, 29...Drive shaft, 32...
. . . Magnetic head, 33 . . . Power mechanism, 63 . . . Drive control circuit section for the motor 25, 64 . . . Amplification circuit section.

Claims (1)

[Claims for Utility Model Registration] A motor that rotationally drives a drive shaft that rotates a magnetic disk, and a motor that holds a magnetic head and reciprocates in the radial direction of the magnetic disk while bringing the magnetic head into contact with the magnetic disk. a head arm section; a power mechanism having a deceleration mechanism that reduces the rotational speed of the drive shaft and converts the rotation of the drive shaft into reciprocating motion of the head arm section; and a drive control circuit that controls the rotational drive of the motor, the magnetic recording and reproducing device recording and reproducing signals from the magnetic head on the magnetic disk, wherein the PC board is connected to the motor. A stator yoke of the motor is formed on the base board, and at least the stator yoke covers an amplifier circuit section of the PC board. 1. A magnetic recording/reproducing device characterized in that the amplifier circuit section is magnetically shielded by extending the amplifier circuit section to a position where the amplifier circuit section is extended to a position where the amplifier circuit section is magnetically shielded.