JPH0255870B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a recording or reproducing device such as a magnetic disk device, and more particularly to a small magnetic disk device using a small magnetic disk.

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.

However, in order to realize such a compact magnetic disk device, a disk drive system for rotationally driving the magnetic disk, a head movement mechanism for moving the head relative to the magnetic disk to change the recording or reproducing track position, etc. are required. However, regardless of the method used, there is a tendency for the configuration to become more complicated and for the equipment to become larger.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems in a recording or reproducing device such as a magnetic disk device, to greatly simplify the structure, to enable miniaturization, and to obtain even higher head positioning accuracy.

To achieve this object, according to the present invention, in the recording or reproducing apparatus described above, the rotational drive shaft for rotationally driving the recording medium is used as the rotational shaft of the access cam for moving the head carriage, and A configuration is adopted in which the cam is attached to the base end side of the rotational drive shaft.

The details of the present invention will be explained below 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 has a through hole 20a at one 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 22 with an E ring 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 arranged above the yoke 30, on which six coils _L1 to _L6 are provided surrounding a through hole 33a into which the bearing holder part 31 fits. , these coils L ₁
When a current flows through ~ _L6 , 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 The current is supplied to the coils L ₁ , L ₃ , and L ₅ through conduction. Also, when white is detected, the output of Tr ₅ turns on IC ₁ , current flows to Tr ₂ , and the coil
Current flows through L ₂ , L ₄ , and L ₆ . At this time, since IC ₂ is an inverter, the output is 0,
Tr ₁ is turned off and no current flows. As a result, no current flows through the coils L ₁ , L ₃ , and L ₅ .

That is, due to the change in information between LED ₁ and Tr ₅ , Tr ₁
and Tr ₂ are alternately switched so that current is alternately passed 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.
It is used as an OFF digital switch, and Tr ₃ is used as an analog switch to control the current flowing through the coil and rotate the rotor 27 which has a built-in 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 37 consisting of LED ₂ and Tr ₆
The rotational frequency, which is the detection result of the pattern 36, is input to 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 2
Controls the base of 3. 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 widened 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.

Furthermore, 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 a 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 head and the floppy disk are synchronized, and the track position and dimensions do not go out of order.

By the way, in reality, 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, when the third pulse is applied, the displacement is expected to be 54 degrees, but δ ₂
The amount of displacement decreases. When the fourth shot is energized, 72
It is common for the rotation stop position of a pulse motor to vary slightly, such as when the motor rotates as scheduled.

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, the pulse motor having the characteristics shown in FIG. When used, the stopping position of the carriage 11 varies at a rate of ±δ ₂ /54°, 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 in the same way. , it is possible to drastically reduce variations in stopping positions. 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 in a state in which it is rotatably fitted into a boss 43. A detection piece 42a is provided protruding from a part of the disk 42, and this has a structure that reflects light by plating or pasting aluminum foil or the like. This detection piece 42a is a photodetector 25 provided on the lower surface of the printed circuit board 20.
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, a detection piece is provided directly on the magnetic head 14,
It can be constructed so that the position of the magnetic head can be known, but in this example, the moving distance per track is 0.125 mm, and the change in the electrical output of the photodetector is minute, so an expensive circuit is required. It's not practical.

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 it is mounted on the gear 39 together with the cam 40 and 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. The diameter of this eccentric pin gauge 101 is D, and the long hole 42c in the radial direction is formed in the disc 42.
When the width of is W, it is set so that D=W, and a long hole 39a into which the eccentric pin 101a fits is formed on the gear 39 side facing the long 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 the 11th
As shown in FIGS. 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, if the screw shaft 45 is rotated, the center of the roller 15 can be rotated with a radius δ, and the cam 40
In other words, 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 the fine adjustment is completed, screw the lock nut 46 onto the upper end of the screw shaft 45,
Fix it in that position. In this way, variations in processing accuracy and installation 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 the top surface,
It has a cylinder 49 on the lower surface, and this cylinder 49 is connected to the output shaft 8.
It is fixed by fitting into the upper end of and screwing the 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.
A start position signal detected by the photodetector 26 is generated every rotation of the 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. It gives a force to attract it towards 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, respectively.

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 in the center along the longitudinal direction.
are formed in these through holes, and the protruding pieces 5 are formed in these through holes.
Guide pins 61 fixed to 7 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 at the front edge of each lever 59, 60, and a guide pin 63 fixed to the side plate 55 is fitted into these notches. .

Furthermore, L-shaped bent portions 59d and 60d are formed at the tips of the levers 59 and 60 at right angles toward the board 54, and these bent portions 59d and 60d are formed at the tip of the side plate 55. It fits into a notch 55e formed on the top surface of the cassette 5, with its tip facing the inside of the side plate 55, and is engaged with both sides 5a and 5d of the tip of the cassette 5 when the cassette 5 is installed.

Further, 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 guide rail 10 provided on the base 6 side. It is in a position where it can be done. Also, between the protrusions 59b and 59e of each lever 59 and 6
Between 0b and 60e are guide portions 59f and 60f that come into contact with a guide roller of an operating lever, which will be described later.

By the way, a projection piece 64 is provided on the front end side of the base plate 54 in a protruding manner approximately at the center thereof, and a lever 66 is rotatably supported at the center part of the front end of the projection piece 64 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
The holding ring 72 is fitted therein and integrated with the holding ring 72 by screws 73, and is rotatably attached to the leaf spring 69. An arcuate portion 71 is provided on the circumferential surface of the rotating body 71.
b is formed, and that 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 serves to support 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 side 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 at both left and right ends of the other end of the leaf spring 69, and serve to press down the cassette 5 from above.

The plurality of punched grooves formed across the through-hole 69a provide elasticity to the portion surrounding the through-hole 69a, and are used to elastically maintain contact between the rotating body 71 and 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 opposite 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 with an opening 83c in between. Base ends 84a, 85a of spring pieces 84, 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.
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 it to 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. Also, upper edges 89a, 9 of support columns 89, 90 that are integral with or separate from the side wall of the base 6
0a 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 projecting pieces 89b, 90b are provided on the outside of the upper edges 89a, 90a of the supports 89, 90, and these projecting pieces 89b , 90b serve to position the outer edges 5c, 5d of the cassette 5.

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 projections 21b and Projection piece 8
9b and 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. A roller 93 is rotatably attached to the inner surface of the pin 92 at a position remote from the pin 92.

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 5
9 and 60 are in a state where they are pulled toward the front by the tensile force of the spring 62. But levers 59, 60
The lower ends of the projecting pieces 59e and 60e are connected to the guide rail 10.
, and maintains this state without falling 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 inward against the tensile force of the spring 62. This movement limit is the elongated hole 59a, 60
It is regulated by a. Eventually lever 59,
As the protrusion 60 moves forward, the protruding piece 59
e, 60e begins to move away from the guide rail 10.

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 54b of the base plate 54 is lowered.
, and then 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 innermost side, the projections 59e and 60e of the respective levers are separated from the guide rail 10 as shown in FIG.
The holder part 3 centered on 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 sandwiched 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 slightly bent with the magnetic head 14 in between, and is in reliable 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 picked up and pulled out, the only thing that restrains the cassette 5 is the springs 75 and 76 of the leaf spring piece 69, so it can be easily pulled out.

As is clear from the above description, according to the present invention, in a recording or reproducing apparatus such as a magnetic disk device, the rotational drive shaft for rotationally driving the recording medium is used as the rotational shaft of the access cam for moving the head carriage. In addition, a configuration was adopted in which the cam was attached to the base end side of the rotational drive shaft. According to this configuration, the functions originally required in this type of recording or reproducing apparatus, namely, rotating the recording medium, moving the head linearly in the radial direction of the recording medium, and easily attaching and detaching the recording medium, are achieved. While ensuring functions such as what is possible,
The mechanism can be simplified. In addition, since the head carriage is moved over the entire head movement range, the cam, which is a relatively large component, can be placed near the center of rotation of the recording medium, improving space efficiency and making the device more compact. Extremely effective. Furthermore, since the centers of rotation of the rotary drive shaft and the cam are concentrated at one point, errors due to positional deviation can be reduced, and the head position accuracy can also be improved.

In addition, in the above-described embodiment, the circumferential surface of the head feeding cam that engages with the head carriage has a continuous surface with the same number of steps as the number of tracks on the magnetic disk, so the track position can be detected reliably. This has the excellent effect of being able to accurately track without being influenced by the characteristics of the pulse motor.

[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... Disc 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... operating lever.

Claims (1)

[Scope of Claims] 1. A recording medium mounting part into which a recording medium is mounted, and a rotary drive shaft which is attached to the leading end of the recording medium mounting part and rotates together with the mounted recording medium. a head for recording or reproducing data on or from the recording medium; a head carriage on which the head is mounted and arranged to be movable in a predetermined direction so as to displace a position facing the head with respect to the recording medium; a cam arranged to move the head carriage in accordance with the rotation of the cam member and change the position of the head relative to the recording medium, the cam member having its center of rotation coaxial with the rotational drive shaft and on its proximal end side; A recording or reproducing device characterized in that it is attached to.