JPH0411941B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic disk device, and more particularly to a small magnetic disk device using a small-diameter magnetic disk, in which the mounting reference surface of a magnetic disk cassette is improved. be.

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, increasing their added value. That's helpful.

In this type of magnetic disk device, with the miniaturization of equipment, for example, a magnetic recording medium with a diameter of about 50 mm, that is, a magnetic disk (floppy disk) is used, and a small size is used to enable high-density recording. There is a growing demand for magnetic disks.

The present invention provides such a compact magnetic disk that is capable of high-density recording and playback, stable quality, stable recording and playback, and configured so that a magnetic disk cassette can be mounted with accurate positioning. The purpose is to provide equipment.

In order to achieve the above object, the present invention employs a structure in which a positioning member is used to position the magnetic disk cassette from its bottom and side surfaces, allowing the magnetic disk cassette to be accurately positioned and mounted.

Hereinafter, the details of the present invention will be explained based on the drawings.

FIG. 1 and subsequent figures 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 has a base portion 1
The magnetic disk can be roughly divided into five parts: a position detection mechanism 2, a holder section 3, a disk holding mechanism 4, and a magnetic disk cassette 5 (hereinafter, the magnetic disk will be referred to as a floppy disk).

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 the holder part 3 detects a floppy disk cassette (hereinafter referred to as
(abbreviated as cassette) 5 is removably attached,
It plays the role of correctly guiding 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 with an appropriate pressing force.

The details of each part will be sequentially explained below.

The base part 1 is assembled based on the base 6, and is equipped with a motor 7 that rotates the floppy disk.
is provided, the output shaft 8 of which is arranged vertically.

Two guide rails 9 and 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 and 10. Coil springs 12 and 13 are attached to the guide rails 9 and 10, and apply a pressing force to the carriage 11 in a direction toward 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 for tracking in conjunction with a positioning mechanism to be described later is attached to the lower surface on the front side thereof.

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 meshes with a gear 18 rotatably supported near the pulse motor 16. gear 1
A pinion gear 19 is integrally provided on the lower surface of 8.

Above the motor 7, the pinion gear 19,
The printed circuit board 20 is attached while avoiding the output shaft 8 of the motor 7. This printed circuit board 20 is
A through hole 20a is provided at one corner, and a pin 21 protruding from the base 6 is fitted into the through hole 20a, and the upper and lower portions of the pin 21 are sandwiched and fixed by E-rings 22.

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

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 from a magnetic metal such as an iron plate into a flat cylindrical shape by press working, and permanent magnets 28 and 29 are fixed at equal angular intervals inside the rotor 27 as shown in FIG. There is. These permanent magnets 28 and 29 are molded from synthetic resin mixed with magnetic powder, and are excellent in mass production. The output shaft 8 is fixed to the rotor 27, and the output shaft 8 is rotatably supported by two upper and lower bearings 32a and 32b fixed to a bearing holder 31 fixed to a yoke 30. Reference numeral 33 denotes a printed circuit board, which is placed above the yoke 30, and on which six coils L ₁ to L ₆ are provided surrounding a through hole 33 a into which the bearing holder 31 is fitted. These coils L ₁ ~
When a current is passed by energizing L ₆ , a magnetic flux is generated, and the rotor 27 is rotated in cooperation with the permanent magnets 28 and 29 of the rotor 27 .

A disk 34 is fixed to the lower side of the rotor 27, as shown in FIGS. 3 and 4. This disk 34
A pattern 35 in which a total of 6 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 formed concentrically on the lower surface of the .

Photodetectors 37 and 38 are fixed on the printed circuit board 33 in correspondence with these patterns 35 and 36.

The photodetector 37 detects the pattern 36 and detects the rotation speed of the rotor 27. In addition, the photodetector 3
8 detects the positional relationship between the coils L ₁ to _{L 6} and the permanent magnets 28 and 29.

A detection circuit using these photodetectors and coils _L1 to _L6 is shown in FIG. In Figure 5
LED ₁ and Tr ₅ constitute a photodetector 38, and LED ₂ and
Tr ₆ constitutes a photodetector 37.

In Fig. 5, the rotation start signal MOT of motor 7
When ON is input to the servo circuit IC ₂ , IC ₂ starts operating and the transistors Tr ₁ , Tr ₃ or Tr ₂ ,
Turn on one of Tr ₃ to turn on coils L ₁ , L ₃ , L ₅
Alternatively, current flows through L ₂ , L ₄ , and L ₆ , and the magnetic fields from the permanent magnets 28 and 29 form a magnetic circuit passing through the yoke 30 , so there is a repulsion between the magnetic flux generated by the coil and the magnetic flux generated by the coil. , suction occurs alternately and the rotor 27 begins to rotate.

This rotation is detected by the photodetectors 37, 38.

Now, when the black color of the pattern 35 is detected by the photodetector 38 consisting of LED ₁ and Tr ₅ , the output of Tr ₅ flows to IC ₁ and IC ₂ , is input to the base of Tr ₁ , and Tr ₁ becomes Current is supplied to coils L ₁ , L ₃ , and L ₅ through the coils. Also, when white is detected, the output of Tr ₅ turns on IC ₁ , current flows to Tr ₂ , and coils L ₂ ,
Current flows through L ₄ and L ₆ . At this time, since IC ₂ is an inverter, the output is 0, and Tr ₁ is
It is turned off and no current flows. As a result, the coil
No current flows through L ₁ , L ₃ , and L ₅ .

That is, by changing the information between LED ₁ and Tr ₅ ,
The configuration is such that Tr ₁ and Tr ₂ 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, Tr ₁ and Tr ₂ are turned ON and OFF.
Tr 3 is used as a digital switch, and Tr ₃ is used as an analog switch to control the current flowing through the coil and rotate the rotor 27 containing a permanent magnet.

A servo IC ₃ 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 accurate pulse time intervals. ₃ and a photodetector 3 consisting of LED ₂ and Tr ₆ .
The rotational frequency, which is the detection result of the pattern 36 by the IC 3, is inputted 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 Tr ₃ , and a large current is supplied to the coils _L1 to _L6 to increase the rotational speed. Also, if the rotation frequency is higher than the reference frequency, a low current is supplied to the base of Tr ₃ ,
A small current is supplied to coils L ₁ to _{L 6} to lower the rotation 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
The base current of Tr ₃ is controlled by comparing it with the reference frequency, and the rotation speed is kept constant.

By the way, specifically, the rotational speed of the rotor 27 during steady state is one rotation every 204 msec.
Since the number of passes of the pattern 35 to the photodetector 38 during one rotation is six, the period for switching Tr ₁ and Tr ₂ is 204/6, which is 34 msec. In addition, the reference pulse time interval for rotating the motor at a constant speed is assumed to be 2 msec, and the drive transistor 23
control the base of. Therefore, pattern 36 is
It is divided into 102 equal parts to enable signal generation of 2 msec.

Since load fluctuations when a magnetic head contacts a floppy disk for recording and reproducing are relatively small, satisfactory rotation can be obtained even if the reference pulse time interval is increased to 2 msec 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 magnet 2 housed in the rotor 27
If 8 and 29 are formed of integrally molded ring-shaped permanent magnets, the magnetic pole boundaries will become unclear during magnetization, so in this example, they are of split type, thereby reducing the mass of the entire permanent magnet. , a space is formed between the magnetic poles to reduce weight.

Also, if such a rotor structure is adopted,
In order to downsize motors in the future, it is highly conceivable that permanent magnet materials will be made of expensive rare earth materials, so the use of split permanent magnets will lead to resource savings and cost reductions.

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 39 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 16, the gear 17 attached to its output shaft 8 rotates 18 degrees. This rotation is caused by gear 18,
The signal is transmitted to the gear 39 via the pinion gear 19.

Incidentally, high precision is required for the relative positional relationship between the magnetic head 14 on the carriage 11 and the output shaft 8 of the motor 7.

The reason for this is that if the dimensional accuracy varies, the cassettes will not be compatible, 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, it is optimal to attach the cam 40 for driving the carriage to the output shaft 8, which is the center of rotation of the floppy disk.

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 the floppy disk is also attached to the output shaft 8, the vibration of the magnetic head 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, for the pulse motor 16,
When three pulses of electricity are applied, 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 Figure 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, δ ₁ rotation is exceeded. Also, 3
When the first pulse is applied, the planned displacement of 54 degrees decreases by _δ2 . Furthermore, the rotation stop position of the pulse motor generally varies slightly, such as when the fourth energization is applied, the pulse motor rotates 72 degrees as planned.

Therefore, if a cam 40 rotated by the pulse motor 16 is used, the rotation angle and displacement have a linear relationship as shown in FIG.
When using a pulse motor with the characteristics shown _in Figure 7, the carriage 11
The stopping position of the magnetic head varies, making it impossible to accurately stop the magnetic head on a predetermined track.

On the other hand, if a cam in which the relationship between rotation angle and displacement changes stepwise as shown in Figure 9 is used, even if the stop position of the pulse motor is shifted by δ ₂ , the cam will not be displaced to the same extent. First, the variation in stop positions 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, the rotational torque of the pulse motor can also be bumped between the gears, making it possible to reduce the rotational torque and power consumption.

For these reasons, in the present invention, the first
As shown in FIG. 0, a plurality of stepped cam surfaces 40a are formed on the circumferential surface of the cam 40. The number of these stepped cam surfaces 40a is 40, which in this embodiment is the same as the number of tracks on the floppy disk. Also,
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 this straight part 4
An arc-shaped recess 40c is formed at the base of 0b.

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 largest diameter track of the floppy disk, a reference signal is generated from the device side, and the number of pulses energized to the pulse motor 16 is calculated to determine the correspondence state with other track positions. We devised a configuration in which the position of the magnetic head is determined by storing it in a control circuit (not shown). 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 39 so as to be rotatably fitted onto the boss 43. A detection piece 4 is provided on a part of the disk 42.
2a is provided protrudingly, and this is structured to reflect light by plating or pasting aluminum foil or the like. This detection piece 42a is detected by the photodetector 25 provided on the lower 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 mm, and the electrical output of the photodetector is Since the changes are minute, expensive circuitry is required, making it 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, so the track position, that is, the head position is detected by the inexpensive photodetector 25. It became possible.

On the other hand, although the cam 40 is mounted on the gear 39 together with the disc 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. The diameter of this eccentric pin gauge 101 is D,
If the width of the long hole 42c in the radial direction formed in the disk 42 is W, it is set so that D=W, and the small hole 39a into which the eccentric pin 101a fits is the gear 39.
It is formed on the side facing the elongated hole 42c.

Therefore, when the eccentric pin gauge 101 is fitted into the long hole 42c, the eccentric pin 101a is fitted into the small hole 39a, and the eccentric pin gauge 101 is rotated,
The disk 42 can be rotated left and right, allowing fine adjustment of the position of the detection piece 42a.

In the present invention, the tracks of the floppy disk are divided into 40 equal parts with a radius of 15 mm to 20 mm, each track being 0.125 mm. Therefore, the magnetic head has a distance of 0.125 between 15 mm and 20 mm centering on the output shaft 8 of the motor 7.
If the disc is not driven accurately at mm pitches, it will not be possible to use floppy disks recorded with other devices.

In addition, the maximum track diameter position of the magnetic head is 20 mm,
If the minimum diameter position of 15 mm is not accurate, it will no longer 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 Figure 11~
It is shown in FIG. That is, the roller 15 is eccentrically attached to the screw shaft 45 via the shaft 15a. This amount of eccentricity is δ.
The screw shaft 45 has a groove 45a formed at its upper end, into which a screwdriver or the like is inserted 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 rotate with a radius δ, and the distance between the roller 15 and the cam 40, that is, the output shaft 8 to which the cam 40 is fixed, and the magnetic head 14 can be reliably fine-tuned. After finishing the fine adjustment, a lock nut 46 is screwed onto the upper end of the screw shaft 45 to 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 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. 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 48 on its upper surface and a cylinder 49 on its lower surface, and is fixed by fitting the cylinder 49 to the upper end of the output shaft 8 and screwing a screw 50 from the side.

A disk 51 is fitted into the cylinder 49 between the disk 47 and the cam 40 through its center hole 51a, and fixed by caulking a pin 51c. 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.

An arcuate spring piece 52 is formed by punching out a part of the disc 51, and a pin 53 is protruded from the upper surface of the free end side. The pin 53 is fitted into a through hole 47a formed in a part 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 fixed to the boss 43 together with the cam 40.

The detection piece 51b protruding from the disc 51 is connected to the output shaft 8.
The photodetector 26 detects each rotation of the starting position 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. Through holes 55a are formed at opposing positions on the distal end sides of these side plates 55, 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.

A protruding piece 57 is protruded from the center of the side plate 55, and a spring 58 is stretched between this protruding piece 57 and a protruding piece 6b protruding from the base 6. On the other hand, a pulling force is applied to the base 6 side.

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

Bent pieces 54c, 54c are formed on the free end side of the substrate 54, and bent pieces 54c are bent upwardly, and bent pieces 5 are formed on the edge of the side plate 55 in a state where they are spread out from side to side.
5b is formed, and a bent piece 55c bent downward is formed below the bent piece 55b.

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

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

Levers 59 and 60 are attached to the outside of the left and right side plates 55. These levers 59, 60 have through holes 59a, 60a formed in their central portions along the longitudinal direction, and the protruding pieces 57 are formed in these through holes.
Guide pins 61 fixed to are respectively fitted. A spring 62 is stretched between the protruding pieces 59b and 60b, which are provided to protrude downward from the tips of the respective levers 59 and 60, and the protruding piece 57. It is pulled toward the front.

Notches 59c, 60c are formed along the longitudinal direction on the front edge of each lever 59, 60, and a guide pin 63 fixed to the side plate 55 is fitted into these notches. .

Further, at the tips of the levers 59 and 60, there is an L-shaped bent portion 5 bent at a right angle toward the board 54 side.
9d and 60d are formed, and these bent portions 5
9d and 60d are fitted 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, so that when the cassette 5 is installed, both sides 5a of the tip of the cassette 5 are inserted. , 5b.

Furthermore, projecting pieces 59e and 60e are provided on the front edge of each lever 59 and 60, and these projecting pieces 59e and 60e are engaged with one of the guide rails 10 provided on the base 6 side. It is in a position where it can be matched.

Further, between the protrusions 59b and 59e of each lever 59 and between 60b and 60e, there are guide portions 59f and 60f that come into contact with guide rollers of the 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 66 is formed into a substantially dogleg shape, and one end of the lever 66 is slidably fitted into a long hole 59g formed in a bent portion 59d formed at the tip of the lever 59. A pin 67 is provided to protrude downward.

Further, a projection 68 is provided on the upper surface of the other end of the lever 66 to engage with a pad arm, which will be described later.

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

The disk 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 rotary body 71 is inserted into the through hole 69a formed in the center of the leaf spring 69 from below the leaf spring 69.
The boss 71a of the leaf spring 6 is fitted into the boss 71a.
Through hole 72a of presser ring 72 located above 9
It is fitted into the holding ring 72 and integrated with the holding ring 72 by screws 73, and is rotatably attached to the leaf spring 69. An arcuate portion 71b is provided on the circumferential surface of the rotating body 71.
This portion fits into the through hole 54a of the substrate 54 of the holder to ensure smooth insertion when the cassette 5 is mounted. 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.

Three through holes 69b are formed in the leaf spring 69, and 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 provided protruding from the center of the tip of the leaf spring 69, 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 76, 76 are formed on both the left and right ends of the other end of the leaf spring 69, and the cassette 5
It plays the role of pressing down from above.

Note that the plurality of punched grooves formed sandwiching the through hole 69a give elasticity to the portion surrounding the through hole 69a, and are used to elastically maintain the contact of the rotating body 71 with the hub of the floppy disk. It is something.

The padded arm 70 has a padded 7 on the bottom surface of its tip.
7, and a leaf spring 78 is connected to the base end, and this leaf spring 78 is fixed to a protrusion 11a protruding from one end of the carriage 11 by a screw 80 via a backing plate 79. . Pad 77 is magnetic head 1
4, and the projection 68 of the lever 66 provided on the lower surface of the pad arm 70 on the substrate 54 side.
A recessed portion 70a is formed at a position that can correspond to the recessed portion 70a. The pad 77 is fitted into the elongated hole 54b of the substrate 54 through a notch 69d formed on the side edge of the leaf spring 69, and is disposed facing the magnetic head 14, pressing the floppy disk from above.

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

That is, the cassette 5 has cassette halves 81 and 82 molded from synthetic resin or the like, and the disk 47 and the rotating body 7 are located at opposing positions in the center of the cassette halves 81 and 82.
Through holes 81a and 82a are formed into which the magnetic heads and pads are inserted, and openings 81b and 82b into which the magnetic heads and pads are inserted are formed near the through holes 81a and 82a.
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 83 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 ends 84a and 85a of the spring pieces 84 and 85 are fixed to the lower surface of the cassette half 81, and their free ends press the liner 83 downward on both sides of the opening 83c. These spring pieces 84, 8
The role of liner 5 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 86, 86 are provided on the lower cassette half 82 side with a through hole 82a in between, and a small hole 8 is provided at a position that does not contact the floppy disk.
2c is formed. The upper end of the pin 21 protruding from the base 6 side is fitted into this small hole 82c, which serves as a hole for positioning 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,
The boss 4 of the disk 47 is located in the center hole 88a.
A pin 53 protruding from the spring piece 52 of the disk 51 is inserted into the through hole 88b formed in the vicinity of which the pin 8 is fitted.
are fitted.

Incidentally, the base 6 side has been devised to constitute a mounting reference surface when a cassette is mounted. That is, as shown in FIG. 16, the pin 21 protruding from the base 6 not only serves to attach the printed circuit board 20, but also serves as a protrusion 21 protruding from the upper edge 21a.
b is inserted into the small hole 82c of the cassette half 82 for positioning. In addition, the upper edge 89a of the support columns 89, 90, which are integral with or separate from the side wall of the base 6,
90a is 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 supports 89, 90 are arranged to form the vertices of a triangle, and protrusions 89b, 90 are provided on the outside of the upper edges 89a, 90a of the supports 89, 90.
b is provided in a protruding manner, and these protruding pieces 89b, 90b
serve to position the outer edges 5c, 5d of the cassette 5.

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

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 92. pin 9
A roller 93 is rotatably attached to the inner surface of the roller 93 at a position remote from the roller 2.

This roller 93 is located at a position in contact with the guide portions 59f, 60f of the levers 59, 60.

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 described 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. 17, and the lever 59,
60 is in a state where it is pulled toward the front by the tensile force of the spring 62. However, the lower ends of the protrusions 59e and 60e of the levers 59 and 60 are in contact with the guide rail 10, and do not descend and maintain this state even when the tensile force of the spring 58 is applied.

At this time, the operating lever 91 is rotated toward the front, and the roller 93 is in contact with the front corner of the guide portions 59f, 60f.

In this state, the lever 66 is moved to the pin 65 via the pin 67 by moving the lever 59 toward the front side.
The protrusion 68 is in contact with the back of the recess 70a on the lower surface of the pad arm 70 as shown in FIG. 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 5 of the cassette 5 are inserted.
b is the bent piece 59d, 6 on the back side of the lever 59, 60
0d, and when the cassette 5 is further pushed in, the levers 59 and 60 move against the tensile force of the spring 62.
moves inward. This movement limit is the elongated hole 59a, 6
It is regulated by 0a. Eventually lever 5
As the protrusions 9 and 60 move forward, the protrusions 59e and 60e begin to separate from the guide rail 10, as shown in FIG.

At the same time, as the lever 59 moves forward, the lever 66 is rotated clockwise in FIG. 2 via the pin 67.
As shown in FIG. 22, the protrusion 68 gradually begins to fit into the recess 70a of the pad arm 70.

As a result, the tip of the pad arm 70 is lowered by the force of the leaf spring 78, and the elongated hole 54 of the base plate 54
b, fits into the opening 81b of the cassette 5, and begins to come into contact with the floppy disk 87.

Eventually, when the levers 59 and 60 are pushed to the farthest position, the protrusions 59e and 60e of the respective levers touch the guide rail 10, as shown in FIG.
The substrate 5 is separated from the substrate 5 due to the tensile force of the spring 58.
The holder part 3 centered at 4 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 edge 21a of the pin 21 and the support column 89,
The lower surface of the cassette 5 contacts the upper edge of the cassette 90, and the cassette 5 is set on the reference surface. At the same time, the pillar 89,
Both end portions 5c and 5d on the rear side of the cassette 5 are positioned and mounted in the left and right direction by the protruding pieces 89b and 90b of the cassette 5.

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 the spring pieces 84 and
Since the floppy disk 87 is pushed through the liner 83 which is pressed by the magnetic head 85, the floppy disk 87 is in a slightly curved state with the magnetic head 14 sandwiched therebetween, so that the floppy disk 87 is in secure contact with the magnetic head 14.

Magnetic recording and reproduction is performed in this state.

When it is desired to remove the cassette 5, push the operation lever 91 downward from the fully installed state shown in FIG. 19 and rotate it clockwise about the pin 92. is pushed upward and pulled back toward the user by the force of the spring 62. Eventually, the lower ends of the protruding pieces 59e, 60e of each lever separate from the guide rail 10, and the entire holder part is locked with the front side raised.

At the same time, by moving the levers 59, 60 toward the front, the pad arm 70 is also raised, and the cassette 5 is pushed back toward the front by a predetermined distance. If the cassette 5 is grabbed and pulled out, the cassette 5 can be easily pulled out because the only thing that restrains the cassette 5 is the spring pieces 75 and 76 of the leaf spring 69.

As is clear from the above description, according to the present invention, in a magnetic disk device in which a cassette containing a magnetic disk is removably mounted, a cassette transfer mechanism that transfers a cassette inserted from a cassette insertion port to a predetermined loading position is provided. means, a spindle for engaging and rotating a magnetic disk in a cassette transferred to the loading position, and a plurality of positioning members for positioning the cassette in the loading position, at least one of the positioning members The pair of positioning members are in contact with the opposing sides of the cassette, and are also in contact with the bottom of the cassette to position the cassette. By abutting the cassettes, the lateral and height positions of the cassettes can be accurately positioned using the outer shape of the cassettes, without having to specifically provide reference holes in the cassettes that correspond to all the positioning members. effective.

[Brief explanation of drawings]

The figure explains one embodiment of the present invention.
The figure is an exploded perspective view of the base part, Figure 2 is an exploded perspective view of the holder part, Figure 3 is an exploded perspective view of the motor, Figure 4 is a perspective view of the rotor as seen from below, and Figure 5 is an exploded perspective view of the holder part. Circuit diagram showing the connection state between the detector and the coil, No. 6
The figure is a side view of the base part, Figure 7 is a diagram showing the relationship between the number of input pulses of the pulse motor and the rotation angle, and Figure 8 is a diagram showing the rotation angle and displacement amount of a general cam shown as a comparative example. A diagram showing the relationship, FIG. 9 is a diagram showing the relationship between the rotation angle and displacement amount of the cam applied to the present invention, FIG. 10 is a plan view of the cam, and FIG. 11 is an attachment of the roller with which the cam comes into contact. An exploded perspective view showing the structure, FIG. 12 is a perspective view of the roller seen from below, and FIG. 13 is a side view showing the arrangement of the cam and roller.
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 cassette attachment reference plane setting structure, and Fig. 1
Figures 7 to 19 are side views illustrating the operation;
The figure is a partially longitudinal side view showing the installed state of the cassette.
FIGS. 21 and 22 are side views illustrating the operation of the pad arm, and FIG. 23 is a perspective view illustrating a fine adjustment method using an eccentric pin gauge. 1...Base part, 2...Position detection mechanism part, 3...
Holder section, 4... Disk holding mechanism, 5... Cassette, 6... Base, 7... Motor, 8... Output shaft, 9, 10... Guide rail, 11... Carriage, 14... Magnetic head , 15... Laura, 1
6...Pulse motor, 20...Printed circuit board, 2
5, 26...Photodetector, 21...Pin, 27...
Rotor, 28, 29...Permanent magnet, 34...Disc, 40...Cam, 47...Disc, 54...
Board, 59, 60, 66... Lever, 69... Leaf spring, 70... Pad arm, 77... Pad,
81, 82... Cassette half, 83, 86...
Raina, 87...Flotspy disc, 88...
Hub, 89, 90... strut, 91... operation lever.

Claims (1)

[Scope of Claims] 1. A magnetic disk device in which a cassette containing a magnetic disk is removably mounted, comprising: a cassette transfer means for transferring a cassette inserted through a cassette insertion port to a predetermined loading position; a spindle that engages with and rotates a magnetic disk in a transferred cassette; and a plurality of positioning members that position the cassette in the loading position, at least one pair of the positioning members facing each other in the cassette. 1. A magnetic disk device characterized in that the cassette is positioned by abutting on each side surface of the cassette and a bottom surface of the cassette.