JPS593762A - Magnetic disk device - Google Patents

Abstract

PURPOSE:To position accurately a cassette for loading, by providing the loading reference surface of a magnetic disk cassette on the base side of a device. CONSTITUTION:The loading reference surface when the cassette 5 is loaded is formed on the side of a base 6. Namely, a pin 21 and props 89 and 90 are stood on the base 6. The pin 21 is used to fit a printed board an also for posi- tioning by fitting its projection 21b in the small hole 82c of a cassette half 82. Projecting pieces 89b and 90b are formed at the outsides of upper end edges of the props 89 and 90 to position the outside edges 5c and 5d of the cassette 5. When the cassette 5 is lowered toward the base 6 together with a holder, the cassette 5 is supported securely on the reference surface with the pin 21 and props 89 and 90, and positioned accurately by the projection 21b and projecting pieces 89b and 90b.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic disk device, and more particularly to a magnetic disk device that uses small diameter magnetic disks and has an improved mounting reference surface for a magnetic disk cassette. 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 computer computers, and in order to improve their added value. It is useful for

With the miniaturization of devices in this type of magnetic disk drive, 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 magnetic disk device that enables high-density recording is used. Demand for discs is increasing.

The present invention enables high-density recording and playback with such a small size.
It is an object of the present invention to provide a magnetic disk device that is capable of stable quality, stable recording and playback, and configured so that a magnetic disk cassette can be mounted with accurate positioning.

In order to achieve the above object, the present invention adopts a structure in which a mounting reference surface is provided on the base side of the device, and a magnetic disk cassette can be accurately positioned and mounted.

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

FIG. 1 and the following are explanations of a magnetic disk device to which the present invention is applied, and FIG. 1 shows an exploded schematic structure of the magnetic disk device.

The magnetic disk device according to the present invention can be roughly divided into five parts: a base section 1, a position detection mechanism 2, a holder section 3, a disk holding mechanism 4, and a magnetic disk cassette 5 (hereinafter referred to as , magnetic disks are called floppy disks).

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

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

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

The details of each part will be sequentially explained below.

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

Two guide rails 9110 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 8 and 10. Coil springs 12 are attached to the guide rails 9 and 10.
13 is attached to 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 that performs tracking in conjunction with a positioning mechanism to be described later is attached to the lower surface on the front side of the magnetic head 14.

A pulse motor 16 for driving the head is 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.
9 is integrally provided.

Above the motor 7 is the pinion gear 19. 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 into a bottle 21 protruding from the base 6, and the lower part thereof is sandwiched between an E ring 22. is fixed.

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 of a magnetic metal such as an iron plate into a flat cylindrical shape by press machining, and a permanent magnet 28.2 is installed inside the rotor 27 as shown in FIG.
9 are fixed at equal angular intervals. These permanent magnets28.
No. 28 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. The Samurai indicated by the reference numeral 33 is a printed circuit board placed above the yoke 30, on which six coils L are mounted surrounding the through hole 33a into which the bearing holder 31 is fitted.
1 to L6 are provided, and when a current is passed through these coils L and -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 yokes 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 33 corresponds to these patterns 35 and 36.
Photodetectors 37, 38 are fixed on top.

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 and 29.

A detection circuit using these photodetectors and coils 1 to L6 is shown in FIG. In Figure 5, LEDI l
! l: Tr5 constitutes the photodetector 38, LED2 and T
r6 constitutes a photodetector 37.

? In figure J5, the rotation start signal of motor 7 is MOT ON.
is input to the servo circuit IC2, IC2 starts operating and the transistor Trl, Tr3, or Tr2
.

Turn on either one between Tr3 and coil L 1 +
L3.

Current flows through L5 or L21 La, L6,
The permanent magnet 28,2! Since the magnetic field from the yoke 30 forms a magnetic circuit passing through the yoke 30, repulsion and attraction alternately occur between the magnetic field and the magnetic flux generated by the coil, and the rotor 27 begins to rotate.

This rotation is detected by said photodetector 37,38.

Now, the light from the LED and the photodetector consisting of Tr6 flows to IC, IC2 and is input to the base of Trl, and Trl becomes conductive to coil L1. L3. Current is supplied to L5. Furthermore, when white is detected, the output of Tr5 turns on IC, and current flows through Tr2, causing coil L2.
L4. Current flows through L6. At this time, since IC2 is an inverter, the output is O, and Trl is O.
It is turned off and no current flows. As a result, coils Ll, L
3. No current flows through L5.

That is, by changing the information between LED and Tr5,
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 IC3 is used to rotate the motor 7 at a constant speed,
A CR component such as a crystal oscillator is used as a part of the servo IC3 to oscillate a reference frequency with a precise pulse time interval, and this is input to the servo IC3 and the LED2
The rotation frequency, which is the detection result of the pattern 36 by the photodetector 37 consisting of the Tr 6 and the Tr 6, is input to the IC 3 and the mutual frequencies are compared. If the rotational frequency generated by rotation of the pattern 36 is lower than the reference frequency, a high current is applied to the base of the Tr3, and a large current is supplied to the coils Ll-L6 to increase the rotational speed. Further, if the rotational frequency is equal to or higher than the reference frequency, a low current is supplied to the base of Tr3, and a small current is supplied to the coils L1 to L6 to lower the rotational speed.

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

By the way, specifically, the rotational speed of the rotor 27 during steady state is 1 rotation at 204 m5ec;
Since the number of passes of the rotating pattern 35 to the photodetector 38 is six, the period for switching Trl and Tr2 is 204/6, which is 34 m5ec. Also, the reference pulse time interval' for rotating the motor at a constant speed is 2
The base of the drive transistor 23 is controlled by the m5ec interval.Since load fluctuations when recording and reproducing data with a magnetic head in contact with a floppy disk are relatively small, satisfactory rotation can be obtained even if the reference pulse time interval is increased to 2 m5ec or more. It will be done. Rather, what is more difficult is the accuracy of dividing the pattern 36, the accuracy of the signal rise time of the photodetector 37, etc.
If the accuracy of these factors can be improved, there is no problem even if the reference frequency is lowered.

By the way, the permanent magnet 28°28 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. This creates a space between the parts and reduces the weight.

In addition, if such a rotor structure is adopted, it is quite possible that the permanent magnet material will be formed from expensive rare earth materials in order to downsize the motor in the future, so using split permanent magnets will save resources and cost. Connected to down.

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

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

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

Therefore, in order to reduce variations in dimensional accuracy between the magnetic head 14 and the output shaft 8, it is optimal to attach a cam 40 for driving the carriage to the output shaft 8, which is the rotation center 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 output shaft 8
The vibrations are transmitted to the cam 40, the carriage 11 vibrates, and the vibrations are transmitted to the magnetic head 14. However, the output shaft 8
Since a floppy disk is also attached to the floppy disk, the vibrations of the magnetic head and the floppy disk are synchronized, and the track position and dimensions do not go out of order.

Incidentally, in practice, when the pulse motor 16 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 due to magnetization accuracy, 61 rotations are exceeded. Also, when the third pulse is applied,
The planned displacement of 54 degrees is reduced by 62 degrees. Also, 4
Generally, the rotational stop position of the Norculus motor varies slightly, such as when the motor is energized, it rotates 72 degrees as planned.

When using a pulse motor with the characteristics shown in Figure 7, ±δ2 is used.
The stop position of the carriage 11 varies at a rate of /54', 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 you use a cam that changes stepwise, 1. <Even if the stop position of the Luss 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. 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 becomes a straight part 40b. An arc-shaped 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 determined by the number of pulses energized to the pulse motor 18. We considered a configuration in which the position of the magnetic head is determined by storing the information 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 the post 43. A detection piece 42a is provided protruding from a part of the disk 42, and is structured to reflect light by being plated or pasted with aluminum foil or the like. This detection piece 42
a is detected by a photodetector 25 provided on the bottom surface of the printed circuit board 20, and a pulse signal is transmitted once per rotation. Therefore, 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.

However, the configuration is such that a detection piece is provided directly on the magnetic head 14 so that the magnetic head position can be known.
mm, and the change in the electrical output of the photodetector is minute, requiring an expensive circuit and being impractical.

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

On the other hand, although the cam 40 and the disk 42 can be placed on the gear 38, a positional deviation occurs due to processing errors or installation errors, and the above-mentioned detection function cannot be fully exerted. For this reason, in the present invention, circular arc-shaped long holes 424k 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 bin gauge 101 as shown in the 23rd tooth is used. This eccentric bin gauge 101 has an eccentric pin 101a at the lower end. If the diameter of this eccentric bottle gauge 101 is D, and the width of the long hole 42c in the radial direction formed in the disk 42 is W, then p=W, and the small hole into which the eccentric pin 101a fits is set so that p=W. 3
9a is formed on the gear 38 side facing the long hole 42c.

Therefore, when the eccentric bottle gauge 101 is fitted into the long hole 42c, the eccentric pin 101a is fitted into the small hole 39a, and the eccentric bottle gauge 101 is rotated, the disc 42 can be rotated left and right, and the detection piece Fine adjustment of the position of 42a becomes possible.

In the present invention, the track of the floppy disk is divided into 40 equal parts with a radius of 15+ml11 to 20 mm, each having a track length of 0.125 mm. Therefore, the magnetic head is 15fflI11 to 20mm with the output shaft 8 of the motor 7 as the center.
If the disc is not driven accurately at a pitch of 0.125 mm, it will not be possible to use a floppy disk recorded with other devices.

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

The mounting structure of the roller 15 solves this problem. The mounting structure of the roller 15 is shown in FIGS. 11 to 13. That is, the roller 15 is
It is mounted eccentrically via the shaft 15a. This amount of eccentricity is δ. The screw shaft 45 has a groove 45a at its upper end.
A screwdriver or the like is inserted into the carriage 11 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. 1O, 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 post 43 in these through holes 4Ge. 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 upper surface and a cylinder 48 on the 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 this cylinder 48 between the disk 47 and the cam 40 through its center hole 51a, and the pin 5
It is fixed by caulking 1c. The disc 51 has a detection piece 51b protruding from its circumferential surface. This detection piece 51b is formed as a reflector so that it can be detected by another photodetector 26 provided on the upper surface of the printed circuit board 20.

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 disk 51 is fixed to the post 43 together with the cam 40.

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

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

That is, the holder portion 3 is assembled based on the substrate 54. The substrate 54 is press-molded from a metal plate, and side plates 55 are formed on both left and right sides thereof. These side plates 5
Through holes 55a are formed at opposite positions on the distal end side of the shaft 5, and a shaft 56 is fitted into these through holes. Both ends of the shaft 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 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 fit is formed in the center of the substrate 54, and an elongated hole 54b into which a magnetic head can fit is formed on the side thereof.

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.

A lever 5JBO is attached to the outside of the left and right side plates 55. These levers 59 and 60 have through holes 59a and 130a formed in the center thereof along the longitudinal direction, and a guide pin 61 fixed to the protrusion 57 is provided in these through holes.
are fitted respectively. Projecting pieces 58b and flo projecting downward from the tip of each lever 59.80.
A spring 62 is stretched between the protruding piece 57 and the protruding piece 57, and constantly draws the respective levers 59 and 130 toward the front side.

A notch 59c and an EIOc 4m are formed along the longitudinal direction on the front edge of each lever 59.80, and a guide pin 6 fixed to the side plate 55 is provided in these notches.
3 is inserted.

In addition, the tip portions of 8-58 and 60 have L-shaped bent portions 59d and 60d bent at right angles toward the board 54 side.
These bent portions 59d, 1 (Od) fit into the notch 55e formed on the upper surface of the tip of the side plate 55, and the tip faces the inside of the side plate 55, and the cassette 5 When the cassette 5 is installed, both sides 5a, 5 of the tip of the cassette 5
b.

Furthermore, each lever 5!3. There is a protrusion 5 on the front edge of H.
9e and 80e are provided in a protruding manner, and these protruding pieces 58e.

60e is located at a position where it can engage with one of the guide rails 10 provided on the base 6 side.

Also, between the protrusions 59b and 59e of each lever 58 and 60
b.

Between 60e and 60e are guide portions 59f and 80f that come into contact with a guide roller of an operating lever, which will be described later.

By the way, a protruding piece 64 is provided on the tip of the base plate 54 at approximately the center thereof, and a lever 66 is rotatably supported at the center of the tip via a pin 65. This lever 66 is formed into a substantially "<" shape, and one end thereof has a bent portion 5 formed at the tip of the lever 58.
A pin 67 is slidably fitted into the elongated hole 59g formed in the hole 9d and projects downward.

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

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

The disc holding mechanism 4 is composed of a leaf spring 69 and a pad arm 70. The leaf spring 69 is formed into a substantially quadrilateral shape, and the leaf spring 69 is inserted into the through hole Ha formed in the center of the leaf spring 69.
The boss 71a of the rotating body 71 is fitted from below the plate spring 69, and the boss 71a is fitted into the through hole 72a of the retainer ring 72 located above the leaf spring 69, and the retainer ring 7 is tightened by the screw 73.
2 and is rotatably attached to the leaf spring 69. An arcuate portion 71b is formed on the circumferential surface of the rotating body 71, and this portion is connected to the through hole 54 of the substrate 54 of the holder.
This ensures smooth insertion when the cassette is mounted on the 5-axis. This rotating body 71 comes into contact with the hub of a floppy disk housed in a cassette, which will be described later, and plays the role of supporting the rotation of the floppy disk from above.

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

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

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

Note that the plurality of punched grooves formed between the through holes 68a provide elasticity to the portion surrounding the through holes 69a.
This is to elastically maintain contact between the rotating body 71 and 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 substrate 54 at a position that can correspond to the protrusion 68 of the groove 8-66 provided on the substrate 54 side. The pad 77 passes through a notch 139d formed on the side edge of the leaf spring 88, fits into the elongated hole 54b of the substrate 54, is disposed facing the magnetic head 14, and presses the floppy disk from above.

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

That is, the cassette 5 has cassette halves 81 and 82 molded from synthetic resin or the like, and a through hole 8 into which the disk 47 and the rotating body 71 are inserted is formed at opposing positions in the center of the cassette halves 81 and 82.
1a and 82a are formed, and openings 81b and 82b into which the magnetic head and pads are inserted are formed in the vicinity thereof. Inside the upper cassette half 81, a disc-shaped liner 83 is fixed at a plurality of locations indicated by reference numeral 83a via an adhesive or the like. This liner 8
3 has a through hole 83b at a position corresponding to the through hole 81a of the cassette half 81, and has an opening 83c at a position opposite to the opening 81b. Spring pieces 84 and 85 are placed 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. These spring pieces 84. ．． The role of the liner 85 is to press the liner 83 against the floppy disk on both sides of the magnetic head and pad 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, sandwiching the through hole 82a, and an indicator 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 has been devised to constitute a mounting reference surface when a cassette is mounted. That is, the first
As shown in FIG. 6, the pin 21 protruding from the base 6 serves not only to attach the printed circuit board 20 but also to the upper edge 21a of the printed circuit board 20.
A protrusion 21b protruding from the cassette half 82 fits into the small hole 82c of the cassette half 82 for positioning. Also, a support 89 that is integral with or separate from the side wall of the base 6. H upper edge 89a,
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 struts 89, 130 are arranged to form each vertex of a triangle, and one end edge 813a, H & (
7) Projection piece 88b on the outside! l]ob is provided protrudingly, and these projecting pieces 88b and 90b are attached to the outer edge 5c of the cassette 5.
, 5d.

Therefore, when the cassette 5 is lowered to the base 6 side together with the holder by the operation described later, the cassette 5 is reliably supported on a certain reference plane by the pin 21 and the support 8J90, and the protrusion 21b and the protrusion 8f3b ,! l]ob.

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 92 at a position remote from the pin 92.

This roller 93 is connected to the guide portion 5 of the lever 59.60.
It is located adjacent to 9F and 80F.

The operating lever 91 has a tendency to rotate clockwise in FIG. 1 about the pin 82 due to its own weight.

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

Before the cassette 5 is installed inside the holder, the front end of the board 54 is raised in three directions 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 protrusions 59e and 80e of the levers 5θ and 80 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 91 is rotated to the front side, and the roller 83
is guide part 5! jj, in contact with the front corner of 80f.

In this state, the lever 66 is rotated counterclockwise in FIG. 2 about the pin 65 via the pin 67 by moving the lever 59 toward the front, and the projection 88 is moved to the
Is there a recess on the bottom surface of the pad arm 7o as shown in the figure? The pad arm 70 is in contact with the back side of Oa, 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 section 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 will be inserted into the back bent piece 59d of the lever 5J60. , 60d, and when the cassette 5 is further pushed in, the levers 58.80 move inward against the tension of the spring 62. This movement limit is the long hole 59
a, regulated by 60a. Eventually lever 58
．． As the protrusion 80 moves forward, the protrusion 59 moves forward as shown in FIG.
e, BOe begins to move away from the guide rail 1o.

At the same time, as the lever 59 moves forward, the lever 66 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 of the pad arm 7o 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 81b of the cassette 5, and the floppy disk 8
Begin contact with 7.

Eventually, when the levers 59 and 80 are pushed to the farthest position, the protrusions 5 of each lever are pushed in as shown in FIG.
9e, f (Oe is separated from the guide rail IO, and the holder part 3 with the board 54 in the center is pulled downward by the tensile force of the spring 58.

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 protrusion 21b of the pin 21 is fitted into the edge 21a of the pin 2 and the upper edge of the support column 89.90. The cassette 5 is set on the reference surface with its lower surface touching. At the same time, both rear ends 5c and 5d of the cassette 5 are positioned and mounted in the left-right direction by the protrusions 89b and 90b of the support columns 88 and 90.

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 is pushed through the liner 83 which is pressed by spring pieces 84 and 85 on both sides, so that the magnetic head 14 The floppy disk 87 is in a slightly curved state when it is sandwiched between the floppy disks 87 and 87, so that the floppy disk 87 is in 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 91 downwards from the fully installed state shown in FIG. 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 Qe is separated from the kite 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 -'. When the cassette 5 is picked up and pulled out, the spring piece 7 of the leaf spring 68 restrains the cassette 5.
Since it is only 5.76, it can be easily withdrawn.

As is clear from the above description, according to the present invention, since the reference surface for mounting the magnetic disk cassette is provided on the base side, accurate cassette mounting is automatically performed just by performing the cassette mounting operation. A cassette can be attached to the position.

[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 the displacement amount of the cam applied to the present invention, the first θ
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;
Figure 5 is a partially enlarged vertical sectional side view of the cassette, Figure 18 is a perspective view showing the reference plane setting structure for mounting the cassette, Figures 17 to 18 are side views explaining the operation, and Figure 20 is the cassette. 21 and 2 are partial longitudinal side views showing the installed state of the
FIG. 2 is a side view illustrating the operation of the pad arm, and FIG. 23 is a perspective view illustrating a fine adjustment method using an eccentric pin gauge. l...Base part 2...Position detection mechanism part 3.
...Holder part 4...Disc holding mechanism 5...
・Cassette 6...Base 7...Motor 8...
・Output shaft 8,1o...Guide rail 11・
... Carriage 14 ... Magnetic head 15 ...
Roller 1B...Pulse motor 20...Printed circuit board 25.28...Photodetector 21...Pin 27...Rotor 28, 29...Permanent magnet 34...Disk 4o... Cam 47... Disk 54... Board 5!3,130.8
8... Lever 69... Leaf spring 7o...
Pad arm 77...Pad 81.82...Cassette half 83.88...Liner 87...Floppy disk 88...Hub 8Jf30...Strut 81...Operation lever Fig. 20 Fig. 21 0 Figure 22. Figure 23

Claims (1)

[Claims] 1) In a magnetic disk device in which a cassette containing a magnetic disk is removably mounted, the cassette is positioned and held on the side of a base to which a holder portion into which the cassette is inserted is rotatably mounted. A magnetic disk device characterized by providing a reference surface. 2) The magnetic disk drive according to claim 1, wherein the reference plane is an upper end surface of the pins and supports arranged to constitute each vertex of a triangle.