JPS593753A - Magnetic disk device - Google Patents

Abstract

PURPOSE:To perform accurate positioning, by jointing the shaft of a roll which is in contact with a cam driven by a pulse motor eccentrically to an end part of a screw which engages a carriage threadably, and rotating the screw for fine adjustment of the position of the roll. CONSTITUTION:The roll 15 supported pivotally on the carriage 11 through the screw 45 in a free rotating state rotates in contact with the peripheral of a gear associated operatively with a magnetic disk shown in the figure as the carriage 11 moves. The projecting part 15a of the roll 15 is jointed eccentrically to the screw 45. The groove of the screw 45 is rotated with a screwdriver to adjust the roll 15 finely within a range of distance delta and then the roll is fixed in the hole 11a of the carriage 11 with a lock nut 46. Thus, the relative positions of the magnetic head and disk are fixed accurately and tracking is perfomred correctly.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic disk device, and more particularly to a magnetic disk device configured to ensure tracking of a magnetic head in a small magnetic disk device using a small diameter magnetic disk. It is related to.

Floppy disk devices, which are widely used as storage devices using magnetic disks, are used in various electronic devices such as robot equipment, personal computers, word processors, electronic typewriters, and pocket computers, and are useful for increasing the added value of these devices. ing.

With the miniaturization of devices in this type of magnetic disk device, for example, magnetic recording media with a diameter of about 50 mm, that is, magnetic disks (floppy disks) are used, and small magnetic disk devices are used to enable high-density recording. Demand for discs is increasing.

SUMMARY OF THE INVENTION An object of the present invention is to provide a small-sized magnetic disk device as described above, which is configured so that tracking can be performed by accurately moving a magnetic head with respect to a recording track of a magnetic disk.

In order to achieve the above object, the present invention provides a cam that contacts a roller provided on the carriage side and is rotated by a pulse motor to move the carriage, and the roller is connected to a screw shaft screwed onto the carriage. We adopted a structure in which the roller is rotatably supported eccentrically at one end, and the position of the roller can be finely adjusted by rotating the screw shaft.

Hereinafter, the present invention will be described in detail based on the drawings.

FIG. 1 and the following illustrate a magnetic disk device to which the present invention is applied, and FIG. 1 shows an exploded schematic configuration thereof.

The magnetic disk device according to the present invention can be roughly divided into five parts: a base portion l, a position detection mechanism 2, a holder portion 3, a disk holding mechanism 4, and a magnetic disk cassette 5 (hereinafter referred to as , magnetic disks are called floppy disks).

The base 1 constitutes the main part of the floppy disk device, and is provided with a magnetic recording/reproducing head and a driving source.

The position detection mechanism 2 detects the track position and detects the track position.
A floppy disk cassette (hereinafter abbreviated as cassette) 5 is removably installed, and serves to correctly guide the floppy disk to a head provided on the base side.

Further, the disk holding mechanism 4 exerts a pressing force on the floppy disk, and serves to bring the head and the floppy disk into contact with an appropriate pressing force.

The details of each part will be sequentially explained below.

The base 1 is assembled with a base 6 as a reference, and is provided with a motor 7 for rotating a floppy disk, the output shaft 8 of which is arranged vertically.

Two guide rails 9 are mounted on the base 6 so as to sandwich the motor 7 therebetween. 10 are horizontally suspended in parallel, and a carriage 11 is slidably fitted into these guide rails 9 and 10. The guide rail 8.10 has a coil spring 12.
13 is attached, and applies a pressing force to the carriage engine 11 in the direction of approaching the output shaft 8 of the motor 7.

A magnetic head 14 for recording and reproducing is fixed on the carriage 11, and a roller 15 that performs tracking in conjunction with a positioning mechanism to be described later is attached to the lower surface on the front side of the magnetic head 14.

A pulse motor 16 for driving the head is installed in one corner of the base 6, and a gear 1 fixed to the output shaft of the pulse motor 16 is installed at one corner of the base 6.
7 meshes with a gear 18 rotatably supported near the pulse motor 16. A pinion gear 18 is integrally provided on the lower surface of the gear 18.

Above the motor 7 is the pinion gear 18. motor 7
The printed circuit board 20 is attached while avoiding the output shaft 8. This printed circuit board 20 has a through hole 20a at the negative corner, and this through hole 20a is fitted with a pin 21 protruding from the base 6, and the pin 21 is fixed between the top and bottom of the pin 20 with an E ring 22. be done.

The corner facing the through hole 20a is fixed to the upper end of the side wall 24 of the base 6 with a screw 23, and the other end is also fixed to the base 6 via a screw.
fixed on the side wall or partition wall.

Photodetectors 25 and 28 each consisting of a light receiving element and a light emitting element are attached to the upper and lower parts of the printed circuit board 20.

By the way, the motor 7 has a structure as shown exploded in FIG. 3. The motor 7 has a rotor 27 formed by pressing a magnetic metal such as an iron plate into a flat cylindrical shape, and inside the rotor 27 there are permanent magnets 28, 28 as shown in FIG.
are fixed at equal angular intervals. These permanent magnets 28.2
No. 9 is molded from synthetic resin mixed with magnetic powder, and is excellent in mass production.

The output shaft 8 is fixed to the rotor 27, and a bearing fixed to a yoke 30 of the output shaft 8 is rotatably supported by two upper and lower bearings 32a and 32b fixed to a holder 31. Reference numeral 33 denotes a printed circuit board, which is arranged above the yoke 30, on which six coil bearings 1 to L6 are provided surrounding a through hole 33a into which the holder 31 is fitted. These coils L1~L
When a current is passed through 6, a magnetic flux is generated, and the rotor 27 is rotated in cooperation with the permanent magnets 28, 28 of the rotor 27.

A disk 34 is fixed to the lower side of the rotor 27, as shown in FIGS. 3 and 4. A pattern 35 in which a total of six black and white zones are alternately arranged at equal angular intervals and a pattern 36 in which a total of 102 black and white zones are formed are concentrically formed on the lower surface of the disk 34.

These patterns 35.3f (corresponding to the printed circuit board 3
3, photodetectors 37, 38 are fixed.

The photodetector 37 detects the pattern 36 and detects the rotor 27.
Detects the rotation speed. Further, the photodetector 38 includes a coil L,
-Detect the positional relationship between L6 and the permanent magnets 28 and 29.

A detection circuit using these photodetectors and coils 1 to L6 is shown in FIG. In FIG. 5, LED 1 and Tr5 constitute a photodetector 38, and LE[12 and Tr6
constitutes a photodetector 37.

In FIG. 5, when the rotation start signal MOT ON of the motor 7 is input to the servo circuit IC2, the IC2 starts operating and the transistors Trl, Tr3, or Tr2
.

Turn on either one between Tr3 and coil Ll + L
3 +L5 or L2, L4. A current flows through La, and the magnetic field from the permanent magnets 28 and 29 forms a magnetic circuit passing through the yoke 30, so that repulsion and attraction alternately occur between the magnetic flux generated by the coil and the rotor 27. begins to rotate.

This rotation is detected by said photodetector 37,38.

Now, when the black color of the pattern 35 is detected by the photodetector 38 consisting of the LED and the Tr5, the output of the Tr5 flows to the IC, tc2, and is input to the base of the Trl.
Trl is conductive and coils Ll, L3 . Current is supplied to L5. Also, when white is detected, the output of Tr5 is I
C, is turned on, current flows through Tr2, and coil L2,
Current flows through L4 and L6. At this time, since IC2 is an inverter, the output is 0 and Trl
is turned off and no current flows. As a result, coil L1
, L3. No current flows through L5.

That is, by changing the information between the LED and the TrS,
Trl and Tr2 are alternately switched to cause current to alternately flow through odd-numbered coils and even-numbered coils.

By the way, since the rotor 27 needs to maintain a certain rotation speed, Trl and Tr2 are set to ON and 0FF (
7) Use Tr3 as a digital switch and use Tr3 as an analog switch to control the current flowing through the coil and rotate the rotor 27 containing a permanent magnet.

Servo IC3 is used to rotate the motor 7 at a constant speed,
A CR component such as a crystal oscillator is used as a part of the servo IC 3 to oscillate a reference frequency with a precise pulse time interval, and input this to the servo IC 3 as well as to the LE[1
The rotation frequency, which is the detection result of the pattern 36 by the photodetector 37 consisting of the Tr 2 and the Tr 6, is input to the IC 3 and the mutual frequencies are compared. If the rotational frequency generated by rotation of the pattern 36 is lower than the reference frequency, a high current is applied to the base of the Tr3, and a large current is supplied to the coils L and -L6 to increase the rotational speed. Further, if the rotational frequency is equal to or higher than the reference frequency, a low current is supplied to the base of Tr3, and a small current is supplied to the coils 1 to L6 to lower the rotational speed.

In this way, the rotation speed of the rotor 27 is detected by the photodetector 37 and the pattern 36, and the servo IC 3 compares it with the reference frequency to control the base current of the Tr 3, thereby making the rotation speed constant.

By the way, specifically, the rotational speed of the rotor 27 during steady state is one rotation at 204 m5ec, and the number of passes of the pattern 35 to the photodetector 38 during one rotation of the rotor 27 is 6.
Therefore, the switching period of Trl and Tr2 is 204/8, which is 34 m5ec. Also, the standard pulse time interval for rotating the motor at a constant speed is 2 m5e.
The base of the drive transistor 23 is controlled as the c interval. Therefore, pattern 36 was divided into 102 equal parts of 2m5.
This allows the ec signal generation to be divided.

Since load fluctuations when a magnetic head contacts a floppy disk for recording and reproduction are relatively small, satisfactory rotation can be obtained even if the reference pulse time interval is increased to 2 m5ec or more. Rather, what is difficult is the precision of dividing the pattern 36, the precision of the signal rise time of the photodetector 37, etc., and if these precisions can be improved, there is no problem even if the reference frequency is lowered.

By the way, the permanent magnets 28°29 accommodated in the rotor 27
If it is formed from an integrally molded ring-shaped permanent magnet, the boundary between the magnetic poles becomes unclear during magnetization. Therefore, in this example, a split type is used, which reduces the mass of the entire permanent magnet and improves the distance between the magnetic poles. form a space.

In addition, if such a rotor structure is adopted, it is quite conceivable that the permanent magnet material will be formed from expensive rare earth materials in order to make the motor more compact in the future. Its use leads to resource saving and cost reduction.

Incidentally, a large-diameter gear 38 and a cam 40 are rotatably supported on the output shaft 8 of the motor 7 via a bearing 41, and the gear 39 meshes with the pinion gear 18, so that the rotation of the pulse motor 16 is controlled. communicated. When a single pulse is applied to the pulse motor 16, the gear 17 attached to its output shaft 8 rotates 18 degrees. This rotation is transmitted to gear 38 via gear 18 and pinion gear 19.

Incidentally, high precision is required for the dimensional accuracy of the relative positional relationship between the magnetic head 14 on the carriage II and the output shaft 8 of the motor 7.

The reason for this is that if the dimensional accuracy varies, compatibility between cassettes will be lost, and recording and playback will become impossible if other cassettes are used.

Therefore, in order to reduce variations in dimensional accuracy between the magnetic head 14 and the output shaft 8, a cam 4 for driving the carriage is attached to the output shaft 8, which is the rotation center of the floppy disk.
It is best to install o.

Further, by attaching the cam 40 to the output shaft 8 via a bearing 41 with excellent rotational efficiency, the influence exerted from the cam on the motor 7 can be reduced, thereby reducing the rotational load.

By the way, as will be described later, since the cam 40 is engaged with the roller 15 provided on the carriage, the vibration of the output shaft 8 is transmitted to the cam 40, the carriage 11 vibrates, and the vibration is transmitted to the magnetic head 14. However, since a floppy disk is also attached to the output shaft 8, the vibration of the magnetic disk and the vibration of the floppy disk are synchronized, and the track position and dimensions do not go out of order.

By the way, in practice, when the pulse motor 16 is energized with three pulses, the angle of the cam 40 changes by 9 degrees,
The carriage 11 is set to move by one track.

However, as shown in Fig. 7, the characteristics of a pulse motor are that when one pulse of electricity is applied, the axis of the pulse motor 16 is displaced by 18 degrees, but when the second pulse is applied, it should be displaced by 36 degrees, but due to the inertia of the rotor. And due to magnetization accuracy, 61 rotations are exceeded. Also, when the third pulse is applied,
The planned displacement of 54 degrees is reduced by 62 degrees. Also, 4
Generally, the rotation stop position of a pulse motor varies slightly, such as when the pulse motor is energized, it rotates 72 degrees as planned.

Therefore, if the cam 40 rotated by the pulse motor 16 has a linear relationship between the rotation angle and the amount of displacement as shown in FIG. 8, a pulse motor with the characteristics shown in FIG. 7 can be used. In that case, niha±δ2/54'
The stop position of the carriage 11 varies by a fraction of the time, making it impossible to accurately stop the magnetic head on a predetermined track.

On the other hand, as shown in Figure 9, the relationship between rotation angle and displacement is
If a cam that changes stepwise is used, even if the stop position of the pulse motor is deviated by 62 minutes, the cam will not be displaced to the same extent as this, and variations in the stop position can be drastically reduced. In addition, even if backlash or eccentricity occurs between power transmission gears,
Errors caused by these can be absorbed, and the magnetic head can be accurately aligned to a desired position. As a result, backlash can be provided between the gears in the rotational torque of the pulse motor, so it is possible to reduce the rotational torque and power consumption.

For this reason, in the present invention, a plurality of stepped cam surfaces 40a are formed on the circumferential surface of the cam 40, as shown in FIG. The number of these stepped cam surfaces 40a is 40, which in this embodiment is the same as the number of tracks on a floppy disk. Further, the circumferential surface of the cam 40 is on a spiral curve, and gradually becomes smaller from the short diameter part to the long diameter part, and the connecting part between the short diameter part and the long diameter part is a straight part 40b, and the base of this straight part 40b is An arcuate recess 40c is formed.

By the way, if it is not always known which track position the magnetic disk 14 currently corresponds to, recording and reproducing errors will occur. Therefore, when the magnetic head is located at a position corresponding to the maximum diameter track of the floppy disk, a reference signal is generated from the device side, and the correspondence state with other track positions is indicated by the number of pulses energized to the pulse motor IB. We devised a configuration in which the position of the magnetic head is determined by memorizing it using a control circuit that does not have a built-in control circuit. This is the disk 42 that constitutes the detection mechanism section 2.

As shown in FIGS. 1 and 23, the disc 42 is mounted on the gear 38 in a state in which it is rotatably fitted into the post 43. A detection piece 42a is provided protruding from a part of the disk 42, and is structured to reflect light by being plated or pasted with aluminum foil or the like. This detection piece 42
a is detected by a photodetector 25 provided on the bottom surface of the printed circuit board 20, and a pulse signal is transmitted once per rotation. Therefore, when the magnetic head 14 is at the maximum diameter track position, the photodetector 25
If it is arranged so that it can be detected by , its position can be detected.

However, it is possible to install a detection piece directly on the magnetic head 14 so that the magnetic and rad positions can be determined, but on the Kinomoto side, the II/rack movement distance is 0.125.
mm, and the change in the electrical output of the photodetector is minute, requiring an expensive circuit and being impractical.

However, in the present invention, the detection piece 42a rotates slowly together with the gear 39, and the amount of movement per track is approximately 2.
．． 5 mm, it became possible to detect the track position, that is, the head position, using the inexpensive photodetector 25.

On the other hand, although the cam 40 and the disk 42 can be placed on the gear 38, a positional deviation occurs due to processing errors or installation errors, and the above-mentioned detection function cannot be fully exerted. For this reason, in the present invention, arcuate long holes 42b are provided in the disc 42 facing each other, and the screws 44 that are screwed onto the gear 38 are fitted into these long holes 42b, so that the disc 40 can be rotated. In this way, the position of the detection piece 42a can be finely adjusted. To perform this fine adjustment, an eccentric pin gauge 101 as shown in FIG. 23 is used. This eccentric pin gauge lot has an eccentric pin 101a at the lower end. If the diameter of the eccentric pin gauge 101 is D, and the width of the long hole 42c in the radial direction formed in the disk 42 is W, then D=W, and the small hole 39 into which the eccentric pin 101a fits.
A is formed on the gear 38 side facing the elongated hole 42c.

Therefore, by fitting the eccentric pin gauge 101 into the elongated hole 42c, fitting the eccentric pin 101a into the small hole 38a, and rotating the eccentric pin gauge 101, the disc 42 can be rotated left and right, and the detection piece Fine adjustment of the position of 42a becomes possible.

In the present invention, the tracks of a floppy disk are divided into 40 equal parts with a radius of 15 mm to 20 mm, and l track 0 is divided into 40 equal parts.
．． It was set to 125 mm. Therefore, the magnetic head will rotate between 15 mm and 20 mm with the output shaft 8 of the motor 7 as the center.
Unless the floppy disk is driven accurately at a pitch of 12511II11, floppy disks recorded with other devices cannot be used.

Furthermore, if the maximum diameter position of the trunk of the magnetic head is 20 mm and the minimum diameter position of 15 rm is not accurate, it will not be a common specification with other devices. Therefore, the dimensional tolerance of each component between the output shaft 8 and the magnetic head 14 cannot be ignored.

The mounting structure of the roller 15 solves this problem. The mounting structure of the roller 15 is shown in FIGS. 11 to 13. That is, the roller 15 is
It is mounted eccentrically via the shaft 15a. This amount of eccentricity is δ. The screw shaft 45 has a groove 45a at its upper end.
A screwdriver or the like is inserted into the screw hole 11a formed in the carriage 11 and screwed into the screw hole 11a. Therefore, when the screw shaft 45 is rotated, the center of the roller 15 can be rotated with a radius δ, and the distance between the roller 15 and the cam 40, that is, the distance between the output shaft 8 to which the cam 40 is fixed and the magnetic field.
The distance between the rads 14 can be reliably finely adjusted.

After finishing the fine adjustment, the screw shaft 45 is screwed into the upper end of the screw shaft 45 with the opening 413 and fixed in that position. In this way, variations in processing accuracy and mounting accuracy are absorbed and adjusted.

As shown in FIG. 10, the cam 4o has a plurality of through holes 40e formed around a central hole 40d into which the output shaft 8 is fitted, and a shaft 43a protruding from the boss 43 in these through holes 40e. It is fixed by fitting and tightening.

A disk 47 is attached to the upper end of the output shaft 8. The disk 47 has a boss 48 on the upper surface and a cylinder 48 on the lower surface, and is fixed by fitting the cylinder 48 to the upper end of the output shaft 8 and screwing a screw 50 from the side.

A disk 51 is fitted into this cylinder 49 through its center hole 51a between the disk 47 and the cam 4o, and the pin 5
It is fixed by caulking 1c. The disc 51 has a detection piece 51b protruding from its circumferential surface. This detection piece 51b is formed as a reflector so that it can be detected by another photodetector 26 provided on the upper surface of the printed circuit board 20.

A portion of the date plate 51 has an arcuate spring piece 52 and a pin 53 protruding from it. The pin 53 is connected to the disk 47.
It is fitted into a hole 47a formed in a part of the disc 47, and faces above the disc 47. This pin 53 is fitted into a through hole formed in the hub of a floppy disk housed in a cassette, which will be described later, and transmits the rotation of the output shaft 8. This disk 51 is fixed to the boss 43 together with the cam 4o.

A detection piece 51b protruding from the disc 51 is detected by the photodetector 26 every rotation of the output shaft 8 and generates a start position signal.

On the other hand, the holder portion 3 has a structure as shown exploded in FIG.

That is, the holder portion 3 is assembled based on the substrate 54. The substrate 54 is press-molded from a metal plate, and side plates 55 are formed on both left and right sides thereof. These side plates 5
Through holes 55a are formed at opposite positions on the distal end side of the shaft 5, and a shaft 56 is fitted into these through holes. Both ends of the shaft 5B are rotatably fitted into through holes 6a formed in the left and right side plates of the base 6.

Further, a projecting piece 57 is provided in the center of the side plate 55,
A spring 58 is stretched between this protruding piece 57 and a protruding piece 6b protruding from the base 6.
It provides a pulling force to the base 6 side.

A through hole 54a into which the disk 47 can be inserted is formed in the center of the substrate 54, and an elongated hole 54b into which a magnetic head can be inserted is formed on the side of the hole 54a.

Bent pieces 54c, 54c bent upward are formed on the free end side edge of the substrate 54, and bent pieces 55b are formed on the edge of the side plate 55 in a state of expanding from side to side.
Furthermore, a bent piece 55c bent downward is formed below the bent piece 55b.

These bent pieces 54c, 55b, 55c are the cassette 5,
It serves as a guide when being installed.

Furthermore, guide pieces 55d for guiding the cassette 5 are formed at the lower ends of the side plates 55, respectively.

Lever 511.80 is attached to the outside of the left and right side plates 55. These levers 59.80 have through holes 59aJOa formed in their central portions along the longitudinal direction, and guide pins 61 fixed to the projections 57 are provided in these through holes.
are fitted respectively. Projecting pieces 59b and Bob protrude downward from the tips of the respective levers 59 and 60.
A spring 62 is stretched between each lever 59 . Go is always drawn to the front side.

For each t<-59, a notch 59c and EiOc are formed along the longitudinal direction on the front edge of eo, and a kite pin 6 fixed to the side plate 55 is provided in these notches.
3 is inserted.

In addition, there is an L-shaped bent portion 58d bent at right angles toward the substrate 54 at the tip of the EiO.
d, and these bent portions 59d and Sod fit into a notch 55e formed on the upper surface of the tip of the side plate 55, so that the tip faces the inside of the side plate 55, and the cassette 5 is Both sides 5a, 5 of the tip of the cassette 5 when installed
b.

Furthermore, each lever is 5! Projecting pieces 59e and 80e are provided on the front edges of II and 60, and these projecting pieces 59e.

80e is located at a position where it can engage with one guide rail 10 provided on the base 6 side.

In addition, each L//<-59 (7) protruding pieces 59b, 58e (7
) between and eob.

8(le) are guide portions 59f and BOf that come into contact with a guide roller of an operating lever, which will be described later.

By the way, a protruding piece 64 is provided on the tip of the base plate 54 at approximately the center thereof, and a lever 66 is rotatably supported at the center of the tip via a pin 65. This lever 6G is formed approximately in the shape of a "〈" character, and one end thereof has a bent portion 5 formed at the tip of the lever 59.
A pin 67 that is slidably fitted into a long hole 59g formed in 8cj is provided to protrude downward.

Further, a protrusion 68 protruding from the upper surface of the other end of the lever 66 engages with a pad arm to be described later.

On the other hand, the disc holding mechanism portion 4 is constructed as shown in FIG.

The disc holding mechanism 4 is composed of a leaf spring 69 and a pad arm 70. The leaf spring 69 is formed into a substantially quadrilateral shape, and a through hole 89a formed in the center thereof is fitted, and the boss 71a is connected to a retaining ring 72 located above the leaf spring 69.
The through hole? 2a, is integrated with the presser ring 72 by screws 73, and is rotatably attached to the leaf spring 69. An arcuate portion 71b is formed on the circumferential surface of the rotating body 71, and this portion is connected to the through hole 5 of the base plate 54 of the holder.
4a to ensure smooth insertion when the cassette 5 is installed. This rotating body 71 comes into contact with the hub of a floppy disk housed in a cassette, which will be described later, and plays the role of supporting the rotation of the floppy disk from above.

The leaf spring 68 has three through holes 89b formed therein.
Pins 74 protruding from the upper surface of the substrate 54 are fitted into these through holes 89b and fixed by caulking.

A spring piece 75 is protruded from the center of the tip of the leaf spring 68, and this spring piece 75 is fitted into the notch 54d formed in the base plate 54, and serves to hold down the cassette 5.

Further, spring pieces 7 are provided at both left and right ends of the other end of the leaf spring 69.
[(,?[i is formed and serves to hold down the cassette 5 from above.

The plurality of punched grooves formed between the through holes 89a provide elasticity to the portion surrounding the through hole E19a, and are used to elastically maintain contact between the rotating body 71 and the hub of the floppy disk. It is.

The pad arm 70 has a pad 77 on the lower surface of its tip, and a leaf spring 78 is connected to its base end.
It is fixed to a protruding piece 11a provided protrudingly from one end of 1. The pad 77 corresponds to the magnetic head 14, and the pad arm 7
A recess 70a is formed on the lower surface of the substrate 54 at a position that can correspond to the protrusion 68 of the lever 66 provided on the substrate 54 side. The pad 77 passes through the notch 61]d formed on the side edge of the leaf spring 69, fits into the elongated hole 54b of the substrate 54, is disposed facing the magnetic head 14, and presses the floppy disk from above.

On the other hand, the cassette 5 has a structure as shown exploded in FIG. 14.

That is, the cassette 5 has cassette halves 81 and 82 molded from synthetic resin or the like, and a through hole 8 into which the disk 47 and the rotating body 71 are inserted is formed at opposing positions in the center of the cassette halves 81 and 82.
1a and 82a are formed, and openings 81b and 82b into which the magnetic head and pads are inserted are formed in the vicinity thereof. Inside the upper cassette half 81, a disc-shaped liner 83 is fixed at a plurality of locations indicated by reference numeral 83a via an adhesive or the like. This liner 83
has a through hole 83b at a position corresponding to the through hole 81a of the cassette half 81, and an opening 83c at a position opposite to the opening 81b. Spring pieces 84 and 85 are arranged between the liner 83 and the cassette half 81, sandwiching the opening 83c. Base end 84a of spring piece 84.85
, 85a is fixed to the lower surface of the cassette half 81, and its free end side holds the liner 83 on both sides of the opening 83c.
It's pushing downward. The role of these spring pieces 84, 85 is to press the liner 83 against the floppy disk on both sides of the magnetic head and pads that sandwich the floppy disk from above and below, thereby maintaining reliable contact between the floppy disk and the magnetic head.

This state is shown in FIG.

Liners 8Et and 8B are provided on the lower cassette half 82 side with a through hole 82a in between, and a small hole 82c is formed at a position that does not come into contact with the floppy disk. A pin 2 protruding from the base 6 side is provided in the small hole 82c.
The upper end of 1 is fitted to form a positioning hole when the cassette is installed.

A floppy disk 87 is accommodated between the liner 83 and the lower cassette half 82. The floppy disk 87 has a hub 88 in the center, and the post 48 of the disk 47 is fitted into the center hole 88a, and the spring piece 52 of the disk 51 is inserted into the through hole 88b formed near the center hole 88a. A protruding pin 53 is fitted.

Incidentally, the base 6 side is devised to constitute a mounting reference surface when a cassette is mounted. That is, the 16th
As shown in the figure, the pin 21 protruding from the base 6 not only serves to attach the printed circuit board 20, but also has a protrusion 21b protruding from its upper edge 21a that fits into the small hole 82c of the cassette half 82. Position the upper edge of the pillar 89.90
8a and 90a are set to be in the same plane as the upper edge 21a of the pin 21, thereby forming a mounting reference plane. The pin 21 and the struts 89.90 are arranged to form each vertex of a triangle, and the upper edge 81]a, 9 of the struts 89.90
A projecting piece 89b and a Sob are provided on the outside of 0a,
These projecting pieces 88b and 90b are the outer edge 5c of the cassette 5.
, 5d.

Therefore, when the cassette 5 is lowered together with the holder toward the base 6 by the operation described later, the cassette 5 is reliably supported on a certain reference plane by the pins 21 and the supports 89 and 90, and also by the protrusions 21b and protrusions. 89b! 30b for accurate positioning.

By the way, on the base 6 side, there is provided an operator 8-91. The operator/<-St is formed as a substantially mouth-shaped frame and is rotatably supported on both sides of the front end of the base 6 via pins 92. A roller 83 is rotatably attached to the inner surface of the pin 82 at a position remote from the pin 82.

This roller 83 is located at a position in contact with the guide portions 59f and fief of the levers 59 and 80.

This operating lever 91 is given the habit of rotating clockwise in FIG. 1 about a pin 92 due to its own weight.

Next, the operating method and operation of the floppy disk device according to the present invention constructed as above will be explained.

Before the cassette I.5 is installed inside the holder, the front end of the board 54 is raised to one side as shown in FIG. It is being pulled towards you by a force. However, the lower ends of the protrusions 59e and 6Qe of the levers 59 and 80 are in contact with the guide rail 10, and do not descend and maintain this state even when the tensile force of the spring 5B is applied.

At this time, the 8-81 is rotated toward the front and the roller 93 is rotated.
are in contact with the front corners of the guide portions 59f and 80f.

In this state, the lever 66 is rotated counterclockwise in FIG. 2 about the pin 65 via the pin 67 by moving the lever a9 toward the front, and the protrusion 8
As shown in FIG. 1, four parts 70a of the lower surface of the pad arm 70
The pad arm 70 is in contact with the back side of the leaf spring 7.
The pad 77 is pushed up in a direction away from the substrate 54 against the pressing force of the pad 8 .

In this state, when the cassette 5 is inserted into the guide portion formed by the bent pieces 54c, 55b, and 55c at the front end of the board 54, the tips 5a and 5b of the cassette 5 are inserted into the levers 59 and 1.
When the bent pieces 59d and flOd on the rear side of the lever 30 are brought into contact with each other and the cassette 5 is roughly pushed in, the levers 59 and 60 move inward against the tensile force of the spring 62. This limit of movement is regulated by the elongated hole 59a and BQa. Eventually lever 5! As It, 80 moves forward, the protrusions 5θe, 80e begin to move away from the guide rail 10, as shown in FIG.

At the same time, as the lever 59 moves forward, the lever 6B is rotated clockwise in FIG. 2 via the pin 67, and as shown in FIG.
It starts to fit inside.

As a result, the tip end of the pad arm 70 is lowered by the force of the leaf spring 78, passes through the long hole 54b of the board 54, and fits into the opening 81b of the cassette 5, and the floppy disk 8
Begin contact with 7.

Eventually, lever 59. When fiO is pushed to the innermost side, as shown in FIG. 19, the projections 59e and EiOe of each lever are separated from the guide rail lO, and the tension of the spring 58 pushes the holder part 3 around the board 54. is pulled downward.

At this time, the protrusion 21b of the pin 21 is fitted into the small hole 82c formed on the back surface of the front end of the cassette 5, and the lower surface of the cassette 5 is fitted onto the edge 21a of the pin 21 and the upper edge of the support 88. are in contact with each other, and the cassette 5 is set on the reference surface. At the same time, pillar 8111,! 30 protruding pieces 89b, Sob
Accordingly, both end portions 5c and 5d on the rear side of the cassette 5 are positioned and mounted in the left-right direction.

In this state, as shown in FIG. 15, the floppy disk 87 is sandwiched between the pad 77 and the magnetic head 14 from above and below, and both sides of the disk are pushed through the liner 83 which is pressed by the spring pieces 84 and 85. magnetic head 14
The floppy disk 87 is in a slightly curved state when it is held between the two, and magnetic recording and reproduction are performed on the magnetic head 14 in this state.

If you want to remove the cassette 5, press the operating lever 91 downwards from the fully installed state shown in FIG. eO is pushed upward and is also pulled back toward the user by the force of the spring 62. Eventually, the projections 59e, 8 of each lever
The lower end of Oe is separated from the guide rail 10, and the entire holder part is locked with the front side raised.

At the same time, the pad arm 70 is also raised by the movement of the EiO to the front side, and the cassette 5 is pushed back to the front side by a predetermined distance. When the cassette 5 is picked up and pulled out, the spring piece 75 of the leaf spring 69 restrains the cassette 5.
．． Since it is only 76, it can be easily drawn out.

As is clear from the above description, according to the present invention, a roller that comes into contact with a cam rotated by a pulse motor is rotatably provided eccentrically at one end of a screw shaft screwed into a carriage, and the screw shaft is Since a structure is adopted in which the position of the 1-reroller can be finely adjusted during rotation, the magnetic head can be accurately aligned with the track position, allowing accurate tracking of the magnetic head.

[Brief explanation of the drawing]

The figures are for explaining one embodiment of the present invention; FIG. 1 is an exploded perspective view of the base portion, FIG. 2 is an exploded perspective view of the holder portion,
Figure 3 is an exploded perspective view of the motor, Figure 4 is a perspective view of the rotor seen from below, Figure 5 is a circuit diagram showing the connection between the photodetector and the coil, and Figure 6 is the base section. A side view, FIG. 7 is a diagram showing the relationship between the number of input pulses of the pulse motor and the rotation angle, and FIG. 8 is a diagram showing the relationship between the rotation angle and displacement amount of a general cam shown as a comparative example. FIG. 9 is a diagram showing the relationship between the rotation angle and displacement amount of the cam applied to the present invention;
The figure is a top view of the cam, Figure 11 is an exploded perspective view showing the installation structure of the roller that the cam contacts, Figure 12 is a perspective view of the roller seen from below, and Figure 13 is a view of the cam and roller. A side view showing the arrangement state; FIG. 14 is an exploded perspective view of the cassette;
Fig. 15 is a partially enlarged longitudinal sectional side view of the cassette, Fig. 16 is a perspective view showing the reference plane setting structure for mounting the cassette, and Fig.
7 to 18 are side views explaining the operation, FIG. 20 is a partially longitudinal side view showing the cassette installed state, FIGS. 21 and 22 are side views explaining the operation of the para-rad arm, and FIG. FIG. 23 is a perspective view illustrating a fine adjustment method using an eccentric bin gauge. 1... Base part 2... Position detection mechanism part 3.
...Holder part 4...Disc holding mechanism 5...
・Cassette 6...Base 7...Motor 8...
・Output shaft 8, 10...Guide rail 11・
... Carriage 14 ... Magnetic head 15 ...
Roller 18... Pulse motor 20... Printed circuit board 25, 2f (... Photodetector 21...
・Bin 27...Rotor 28, 29...Permanent magnet 34...Disk 40...Cam 47...
Disk 54...Substrate 59,80. EL
S... Lever 68... Leaf spring 70...
Pad arm 77...Pad 81.82...Cassette half CI, 8 [f...Liner 87...Floppy disk 88...Huff 89.90...Strut 81...Operating lever No. 20 Figure 21 Figure 0 Figure 22 Figure 23

Claims (1)

[Claims] In a magnetic disk drive in which a magnetic disk cassette is removably attached, there is a carriage on which a magnetic head is mounted and is pressed in a certain direction, and a cam that is rotated by a pulse motor while in contact with a roller provided on this carriage. the roller is rotatably mounted eccentrically to one end of a screw shaft screwed into the carriage;
A magnetic disk device characterized in that the position of the roller can be finely adjusted by rotating the screw shaft.