JPS593747A - Magnetic disk device - Google Patents

Abstract

PURPOSE:To hold securely a magnetic disk and a magnetic head in contact and to prevent errors in recording and reproduction, by allowing the head to press a surface of the disk strongly into a mountain section shape when the disk cassette is loaded. CONSTITUTION:A pad 77 and the magnetic haed 14 are inserted from through- holes 81a and 82b of cassette halves 81 and 82 to clamp the magnetic recording disk 87. The magnetic head 14 projects more than the disk surface A by distance delta and the disk 87 is rotated so that its section is in the mountain shape. Thus, the magnetic head 14 and magnetic disk 87 are held in contact securely and recording and reproduction are carried out accurately.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic disk device, and more particularly, to a magnetic disk device that allows a magnetic disk and a magnetic head to be in reliable contact with each other in a small magnetic disk device that uses a small diameter magnetic disk. It is related to the device.

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. It's helpful.

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 to enable high-density recording. There is a growing demand for small magnetic disks.

An object of the present invention is to provide a small-sized magnetic disk device as described above, in which when a magnetic disk cassette is installed, the magnetic disk and the magnetic head can surely come into contact with each other. The purpose is

In order to achieve the above object, the present invention arranges the magnetic head so that the tip of the magnetic head is located beyond the surface where the magnetic disk exists when the magnetic disk cassette is installed. A new structure was adopted.

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 includes a base portion l, a position detection mechanism 2, a holder portion 3, a disk holding mechanism 4, a magnetic disk case 7. (hereinafter, magnetic disks are referred to as 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 (abbreviated as cassette) 5 is removably attached thereto, and serves to correctly guide the floppy disk to the 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 each other by applying appropriate pressing force.

The details of each part will be sequentially explained below.

The base part 1 is assembled with a base 6 as a reference, and is provided with a rotor 7 for rotating a floppy disk, and its output shaft 8 is arranged vertically.

Two guide rails 9.10 are horizontally suspended in parallel on the base 6 so as to sandwich the motor 7 therebetween, and a carriage 11 is slidably fitted into these guide rails 9.10. Coil springs 12 are attached to the guide rails 9 and 1o.
13 is attached to apply a pressing force to the carriage 11 in a direction toward the output shaft 8 of the motor 7.

On the carriage 1 is a magnetic head 14 for recording and reproducing.
is fixed, and on the lower surface of the front side there is a roller 15 that performs tracking in conjunction with a positioning mechanism to be described later.
is installed.

A pulse motor 16 for driving the head is attached to one corner of the base 6, and a gear 17 fixed to its output shaft is a gear 1 rotatably supported near the pulse motor 16.
It meshes with 8. The pinion gear 1 is located on the underside of the gear 18.
8 are integrally provided.

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 to the side wall or partition wall soil.

Photodetectors 25 and 26 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 permanent magnets 28 and 29 are installed inside the rotor 27 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. When a current flows through these coils 1 to L6, a magnetic flux is generated, and in cooperation with the permanent magnets 28 and 29 of the rotor 27, the rotor 27
is rotated.

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.

The printed circuit board 3 corresponds to these patterns 35 and 313.
3, photodetectors 37, 38 are fixed.

The photodetector 37 detects the pattern 36 and detects the rotor 27.
Detects the rotation speed. In addition, the photodetector 38 is connected to the coil L1.
- Detect the positional relationship between L6 and the permanent magnets 28, 213.

A detection circuit using these photodetectors and coils Ll"'L6 is shown in FIG. 5. In FIG.
and Tr5 constitute a photodetector 38, and LED2 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 102, the IC2 starts operating and the transistors Tr1. Tr3 or Tr2
.

Turn on either one between Tr3 and coil LL, L3゜L
5 or L2. L4. A current flows through L6, and the magnetic field from the permanent magnets 28 and 29 forms a magnetic circuit passing through the yoke 3o, 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 LED 1 and Tr5, the output of Tr5 flows to ICI and IC2, and is input and supplied to the base of Trl. Further, when white is detected, the output of Tr5 turns on IC1, current flows through Tr2, and current flows through coils L2 + L4 + L6. At this time, since IC2 is an inverter, the output is 0, Trl is turned off, and no current flows. As a result,
No current flows through the coils L 1 , L3, and 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 number of rotations, Trl and Tr2 are used as ON/OFF digital switches, and Tr3 is used as an analog switch to control the current flowing through the coil and turn it into a permanent magnet. The rotor 27 containing the rotor 27 is rotated.

Servo ■C3 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 IC3 to oscillate a reference frequency with accurate pulse time intervals, which is input to the servo 103 and also output to the LED2.
The rotational frequency, which is the detection result of the pattern 38 by the photodetector 37 consisting of 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 L1 to L6 to increase the rotational speed. If the one-rotation frequency is equal to or higher than the reference frequency, a low current is supplied to the base of the Tr3, and a small current is supplied to the coils L1 to L6 to reduce the number of rotations.

In this way, the rotation speed of the rotor 27 is detected by the photodetector 37 and the pattern 3B, 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 Tri and Tr2 is 204/8, which is 341 seconds. Also, the standard pulse time interval for rotating the motor at a constant speed is 2 m.
The base of the drive transistor 23 is controlled at 5ec intervals. Therefore, pattern 36 is divided into 102 equal parts.
This allows the fflSeC 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 accuracy of dividing the pattern 38, the accuracy of the signal rise time of the photodetector 37, etc., and if these accuracy 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. In addition, if such a rotor structure is adopted, it is highly likely that the permanent magnet material will be made of expensive rare earth materials in order to make the motor more compact in the future. Therefore, using split permanent magnets leads to resource saving and cost reduction.

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

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 the variation 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.
In addition, 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, 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 the floppy disk is also attached to the output shaft 8, the vibrations of the magnetic hend and the vibrations of the floppy disk are synchronized, and the track position and dimensions do not go out of order.

Incidentally, in practice, when the pulse motor 1B is energized with three pulses, the angle of the cam 40 changes by 9 degrees, and 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 δ1 rotation exceeds due to magnetization accuracy. 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 angle of one rotation and the amount of displacement as shown in FIG. 8, a pulse motor with the characteristics shown in FIG. 7 can be used. In this case, the stop position of the carriage 11 varies at a rate of ±δ2154°, 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 the variation in the stop position can be drastically reduced.

Further, even if backlash or eccentricity occurs between the power transmission gears, the errors caused by these can be absorbed, and the magnetic head can be accurately aligned with the 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. 1O. 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 head 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 16. 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 4 that constitutes the detection mechanism section 2.
It is 2.

As shown in FIGS. 1 and 23, the disc 42 is mounted on the gear 38 so as to be rotatably fitted into the boss 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, if this detection piece 42a is arranged so that it is detected by the photodetector 25 when the magnetic head 14 is at the maximum diameter track position, that position can be detected.

Of course, it is possible to provide a detection piece directly on the magnetic head 14 so that the position of the magnetic head can be determined, but in this embodiment, the moving distance per track is 0.125 am.
, and since the electrical output change of the photodetector is minute,
It requires expensive circuitry and is impractical.

However, in the present invention, the detection piece 42) rotates slowly together with the gear 39, and the amount of movement per track is approximately 2.
．． 5 mff1, 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 is mounted on the gear 38 together with the disk 42, positional deviations may occur due to processing errors or mounting errors, and the above-mentioned detection function may not be fully exerted. For this reason, in the present invention, arc-shaped long holes 42b are provided in the disc 42 facing each other, and screws 44 that are screwed onto the gear 39 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 101 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 39a, and rotating the eccentric pin gauge 101, the one circular plate 42 can be rotated from side to side. 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 is centered on the output shaft 8 of the motor 7 between 15 mm and 20 mm.
If the floppy disk is not driven accurately at a pitch of 125 mm, floppy disks recorded with other devices cannot be used.

Furthermore, unless the maximum track diameter position of the magnetic head is 20 mm and the minimum track diameter position of 15+mff1 is 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 structure of several rollers 15 solves this problem. The mounting structure of the roller 15 is shown in FIGS. 11 to 13. That is, the roller 15 is
Several pieces are provided eccentrically through 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 this and screwed into a screw hole 11a formed in the carriage 11.

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 it and the cam 40 is
That is, the distance between the output shaft 8 to which the cam 40 is fixed and the magnetic head 14 can be reliably finely adjusted. After finishing the fine adjustment, tighten the lock nut 4 on the upper end of the screw shaft 45.
6 and fix it in that position. In this way, variations in processing accuracy and mounting accuracy are absorbed and adjusted.

As shown in FIG. 10, the cam 40 has a plurality of through holes 4Qe formed around a central hole 40d into which the output shaft 8 is fitted, and a shaft 43a protruding from the post 43 into these through holes 40e. are fitted and fixed by caulking or other methods.

A disk 47 is attached to the upper end of the output shaft 8. The disk 47 has a boss 4B on the upper surface and a cylinder 49 on the lower surface, and is fixed by fitting the cylinder 48 to the upper end of the output shaft 8 and screwing the screw 50 from the side.

A disk 51 is fitted into this cylinder 48 between the disk 47 and the cam 40 through its center hole 51a, and the pin 5
The zero disc 51, which is fixed by caulking 1c, 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 28 provided on the upper surface of the printed circuit board 20.

An arcuate spring piece 52 is punched out from a part of the disk 51, and a pin 53 is formed on the upper surface of the free end side of the spring piece 52.
is installed protrudingly. The pin 53 is fitted into a through hole 47a formed in a portion of the disk 47 and faces above the disk 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 disc 51 is connected to the cam 4o and a detection piece 51 protruding from the disc 51.
b is detected by the photodetector 2B 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 56 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 left and right. A bent piece 55c bent downward is formed on the lower side of the bent piece 55b.

These bent pieces 54c, 55b, and 55c serve as guides when the cassette 5 is installed.

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

Lever 511.60 is attached to the outside of the left and right side plates 55. These levers 511. f! O is 5 in the center
Through holes 59a and 80a are formed along the longitudinal direction, and guide pins 81 fixed to the protruding piece 57 are fitted into these through holes, respectively. Each lever 59
．． A protruding piece 511 is provided at the tip of 80 to protrude downward.
b, a spring 62 is installed between EIOb and the protruding piece 57;
The levers 59 and 80 are always pulled toward the front.

Notches 59c, 80c are formed along the longitudinal direction on the front edge of each lever 5Q, 8(l), and in these notches there is a guide and an idle pin 63 fixed to the side plate 55.
is inserted.

Further, the tip of the lever 58,60 has an L-shaped bent portion 5!3d bent at right angles toward the board 54, [(O
d is formed, and these bent portions 59d and find are cutout portions 55e formed on the upper surface of the tip portion of the side plate 55.
5a on both sides of the front end of the cassette 5 when the cassette 5 is installed,
5b.

Further, a protrusion 5 is provided on the front edge of each lever 59, 60.
9e and 60e are provided in a protruding manner, and these protruding pieces 58e.

130e is located at a position where it can engage with one guide rail 10 provided on the base 6 side.

In addition, each lever 59] between the projecting pieces 58b and 511e and 6
0b.

Between 60e and 60e are guide portions 58f and 130f that come into contact with guide rollers of an operating lever, which will be described later.

Incidentally, a projecting piece 64 is provided on the tip end of the base plate 54 at approximately the center thereof, and a lever 86 is rotatably supported on the center portion of the tip portion via a pin 65. This lever 6B is formed into a substantially r<J shape, and one end thereof has a bent portion 5 formed at the tip of the lever 58.
A pin 67 that is slidably fitted into the elongated hole 59g formed in the hole 9d is provided to protrude downward.

Further, a projection 6 is provided on the upper surface of the other end of the lever 66 to engage with a pad arm 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 B9 and a pad arm 70. The leaf spring 69 is formed into a substantially quadrilateral shape, and a boss 71a of the rotating body 71 is fitted into the opening 169a formed at the center of the leaf spring 69 from below the leaf spring θ9. Presser ring 72 located
An arcuate portion 71b is formed on the circumferential surface of a six-rotator 71 that is fitted into a through hole 72a and integrated with the presser ring 72 by a screw 73, and is rotatably attached to the leaf spring 68. This part is the through hole 5 of the substrate 54 of the holder.
4a and cassette it. 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 90-tip 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 69b and fixed by caulking.

A spring piece 75 is protruded from the center of the tip of the leaf spring B8, and this spring piece 75 is fitted into a 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.
B, 76 is formed and serves to hold down the cassette 5 from above.

In addition, the plurality of punched grooves formed between the through holes 61]a give elasticity to the portion surrounding the through holes Ha,
This is to elastically maintain the contact of the rotating body 71 with the hub of the floppy disk.

The pad arm 70 has a pad 77 on the lower surface of its distal end, 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 holder 0 at a position that can correspond to the protrusion 68 of the lever 68 provided on the substrate 54 side. The pad 77 passes through a notch 6θd formed on the side edge of the leaf spring 68, 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 1 into which the disc 47 and the rotating body 71 are inserted is formed at opposing positions in the center of the cassette half 81 and 82.
11a 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 liner 83 formed in a disc shape is fixed at a plurality of locations indicated by reference numeral 83a via an adhesive or the like. This liner 8
3 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 provided between the liner 83 and the cassette half 81 at the opening 83c.
It is placed between the two. Base end 84 of spring piece 84.85
a, 85a is fixed to the lower surface of the cassette half 81, and its free end side presses the liner 83 downward on both sides of the opening 83c. 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 88 and 86 are provided on the lower cassette half 82 side, sandwiching the through hole 82a, and a small hole 82c is formed at a position that does not come into contact with the floppy disk. A pin 21 protruding from the base 6 side is provided in this small hole 82c.
The upper end of the cassette 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, into which the post 48 of the disk 47 is fitted, and into which the spring piece 52 of the disc 51 protrudes into a through hole 88b formed near the center hole 88a. The provided 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 18th
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 bar 282. The upper edge 89a of the support column 89, 110 that performs positioning and is integral with or separate from the side wall of the base 6.
, 90a are set to be in the same plane as the upper edge 21a of the pin 21, thereby forming a mounting reference plane. pin 21
and struts 811.90 are arranged to form the vertices of a triangle, and protruding pieces 8!3b, 90b are provided on the outside of the upper edges 88a, 90a of the struts 89, 80, and these protruding pieces 119b , 130b is the outer edge 5c of the cassette 5,
It plays the role of positioning 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 the protrusions 21b, Accurate positioning is achieved by the projecting pieces 89b and 90b.

By the way, an operating lever 91 is provided on the base 6 side. The operating lever 91 is formed as a substantially U-shaped frame and is rotatably supported on both sides of the front end of the base 6 via pins 82 . 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 5θr and eor of the levers 59 and 60.

This operating lever 81 is given the habit of rotating clockwise in FIG. 1 about a pin 82 due to its own weight.

On the other hand, in the apparatus of the present invention, the mounting structure of the magnetic head 14 is as shown in FIG. 24.

That is, when the floppy disk cassette 5 is installed, the tip of the magnetic head 14 is placed beyond the surface where the floppy disk 87 is located. If the distance exceeded is δ, then due to the existence of δ, the floppy disk 8
7 undergoes slight mountain-shaped deformation. As a result, the floppy disk 87 is given elasticity to restore its original state, and has the property of coming into close contact with the magnetic head 14, so that the floppy disk 87 always comes into contact with the magnetic head 14.

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 5 is installed inside the holder, the front end of the board 54 is lifted upward as shown in FIG.
It is in a state where it is pulled toward this side by the tensile force of 2. However, the lower ends of the east banks 59e and 60e of the levers 5111.110 are in contact with the guide rail IO, and do not descend even when the tensile force of the spring 58 is applied, but maintain this state.

At this time, the operating lever 81 is rotated to the front side, and the roller 83
is in contact with the front corner of the guide portion 58f, EIOf.

In this state, the lever 66 is rotated counterclockwise in FIG. 2 about the pin 65 via the pin 67 due to the movement of the lever 58 toward the front side, and the protrusion 68 is in the 21st position.
As shown in the figure, the pad arm 70 is in contact with the back side of the recess 70a on the lower surface of the pad arm 70, and the pad arm 70 is connected to the leaf spring 78.
The pad 77 is pushed up in a direction away from the substrate 54 against the pressing force.

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 move to the lever 511,
When the cassette 5 comes into contact with the bent pieces 59d and 130d on the back side of the lever 59. ftO moves inward. This limit of movement is regulated by the elongated hole 59a and ElOa. Eventually, as the levers 59, 130 move forward, the protrusions 58e, f30e begin to separate from the guide rail 10, as shown in FIG.

At the same time, as the lever 58 moves forward, the lever 68 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 elongated hole 54b of the board 54, and fits into the opening Bib of the cassette 5, and the floppy disk 8
Begin contact with 7.

Eventually, when the lever 5+3.80 is pushed to its farthest position, the protrusions 59e and 8Qe of each lever separate from the guide rail 10, as shown in FIG. holder part 3
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, both ends 5c and 5d on the back side of the cassette 5 are positioned and mounted in the left-right direction by the projections 89b and 90b of the support columns 89 and 90.

In this state, as shown in FIG. 15, the floppy disk 87 is held between the pad 77 and the magnetic head 14 from above and below, and is pushed through the liner 83, which is pressed on both sides by the spring pieces 84 and 85, so that the magnetic head 1
4, the floppy disk 87 is slightly bent and comes into secure contact with the magnetic head 14.

In this state, magnetic recording and reproduction are performed.

If you wish to remove the cassette 5, press the operating lever 9] downward from the fully installed state shown in FIG. 19 and rotate it clockwise about the pin 82. 80 is pushed upward and 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, by moving the lever 59.80 toward the front, the pad arm 70 is also raised, and the cassette 5 is pushed back toward the front by a predetermined distance. When the cassette 5 is picked up and pulled out, what restrains the cassette 5 is the spring piece 75 of the leaf spring e8.
Since it is only 78, it can be easily pulled out.

As is clear from the above description, according to the present invention, a1
The magnetic head is arranged so that the tip of the magnetic head is located beyond the surface where the magnetic disk exists when a disk cassette is installed, so the magnetic head cross-sections the magnetic disk at the contact surface with the magnetic disk. Since the magnetic disk contacts the magnetic head in a state where it is deformed into a mountain shape, the magnetic disk is pressed against the magnetic head by its own elasticity, and an excellent effect is obtained in that the contact with the magnetic head can always be made reliably.

[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 plan 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 the arrangement of the cam and roller. Fig. 14 is an exploded perspective view of the cassette; Fig. 14 is an exploded perspective view of the cassette;
Fig. 5 is a partially enlarged longitudinal sectional side view of the force kit, Fig. 18 is a perspective view showing the reference plane setting structure for mounting the cassette, Figs. 17 to 18 are side views explaining the operation, and Fig. 20 is Partially longitudinal side view showing the installed state of the cassette, Figures 21 and 2
Figure 2 is a side view illustrating the operation of the pad arm, Figure 23 is a perspective view illustrating the fine adjustment method using an eccentric pin gauge,
FIG. 24 is a partially enlarged vertical sectional side view illustrating the arrangement structure of the magnetic head. It is. ■...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 25.28... Photodetector 21... Pin 27... Rotor 28, 29... Permanent magnet 34... Disc 40... Cam 47...Disc 54...Substrate 59,80. IIIE
I... Lever 68... Leaf spring 70...
Pad arm 77... Pad 81.82.
...Cassette half 83.8El...liner 8
7...Floppy disk 88...Hub 89.
90...Strut θ1...Operation lever Fig. 16 5d Fig. 17 Fig. 20 Fig. 21 Fig. 0 Fig. 22 Fig. 23

Claims (1)

[Claims] In a magnetic disk device in which a magnetic disk cassette is removably attached, the magnetic head is arranged so that the tip of the magnetic head is located beyond the surface where the magnetic disk is placed when the magnetic disk cassette is installed. A magnetic disk device featuring: