JPH0516116B2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field] The present invention relates to a disk mounting device for mounting a disk-shaped recording medium such as a magnetic disk, and more particularly to a disk mounting device with an improved assembly structure of a chassis portion. be.

[Prior Art] Since compatibility is required between a magnetic disk device and a magnetic disk, it is necessary to mount a magnetic head at a predetermined position on a magnetic disk that is rotated via a motor shaft.

When mounting this magnetic head, it is necessary to perform precise positional adjustment, and if the mounting mechanism for the magnetic disk cassette is located above the magnetic head, there is a drawback in that it gets in the way of the adjustment work.

[Objective] The present invention has been made in order to eliminate the above-mentioned conventional drawbacks, and it is an object of the present invention to provide a disk mounting device configured such that the position and dimensions of a magnetic head, etc. can be freely adjusted. It is an object.

[Example] The details of the present invention will be described below based on the example shown in the drawings.

The magnetic disk device according to the present invention is assembled using a chassis 1 as a reference. The chassis 1 is configured as a U-shaped frame body having left and right side plates 2, 2, and guide grooves 3, 3 are formed in opposing positions of each side plate 2, 2 downward from the upper edge. There is. A roller, which will be described later and is projected from the cassette guide side, is fitted into these guide grooves 3, 3.

Further, a guide hole 4 is formed horizontally between the guide grooves 3, 3 at opposing positions of the side plates 2, 2, and a guide hole 4 is formed horizontally at the front side edge of the side plates 2, 2. A groove 5 is formed. Guide rollers of a slide frame, which will be described later, are fitted into these guide holes 4 and guide grooves 5.

On the other hand, three positioning pins 7 are provided protruding from the bottom plate 6 of the chassis 1 in a predetermined arrangement.

These pins 7 position the cassette in the vertical direction, which will be described later.

A pulse motor 8 that serves as a driving source for moving the magnetic head is mounted on one end of the bottom plate 6 of the chassis.
a, 8a, and a projecting piece 9 cut and raised from the bottom plate 6 is protrudingly provided in the vicinity thereof.
A through hole 10 is formed in the projecting piece 9, and a through hole 11 is formed in one side plate 2 while facing the through hole 10.
is formed. Using these through holes 10 and 11, a guide shaft 12, through which a head mount to be described later is guided, is horizontally mounted.

Also, on the front side of the chassis 1, a side plate 2,
Another guide bar 13 is horizontally suspended between the two in parallel with the guide shaft 12.

On the other hand, a drive gear 14 is fixed to the output shaft below the pulse motor 8, and this drive gear 14 meshes with a gear 15 rotatably supported on the bottom plate 6.

A through hole 16 is formed approximately in the center of the bottom plate 6, and a boss 17 is attached to this through hole 16 for supporting a rotational drive mechanism for a magnetic disk.

As shown in FIG. 3, the boss 17 has a flange 17a on the outer periphery of its central part.This flange 17 is stacked on the top surface of the bottom plate 6, and the lower part of the boss 17 is inserted into the through hole 16.
The flange 17a is fixed with the screw 18.

Inside this boss 17 is a pair of upper and lower bearings 1.
A rotating shaft 20 is rotatably supported via 9 and 19. A collar 21 is arranged between the upper and lower bearings 19. The outer ring of each bearing 19, 19 is press-fitted into the boss 17.

A coupler 22 is fixed to the upper end of the rotating shaft 20. The coupler 22 is fitted into the center hub of the magnetic disk cassette, and the flange 22
A positioning pin 23 is fitted into the hole a so that it can move up and down.

The lower end of the pin 23 is fixed to the free end side of the leaf spring 24 below the flange 22a, and is given the habit of always moving in the protruding direction.

The lower surface and upper bearing 19 of this coupler 22
A spring 25 is elastically loaded between the inner ring and the inner ring, and by pressing the inner ring downward, a relative positional shift is created between the inner ring and the outer ring, and uniform contact between the inner and outer rings and the ball is achieved. This eliminates rattling between the inner and outer rings and prevents the rotating shaft 20 from wobbling.

A gear 27 is fitted and fixed to the boss 17 via a boss 28 with the cam 26 facing upward, but the gear 27 is meshed with the gear 15 and directs the rotation of the pulse motor 8 via the cam 27 to the head side. Communicate to. A tightening washer 29 is fitted on the outside of the boss 28 to prevent the cam 26 and the like from coming off.

On the other hand, what is designated by the reference numeral 30 is a head stand, which is formed into an elongated plate shape. One end of the head stand 30 is connected to the guide shaft 12 via a linear bearing 31.
It is slidably fitted into the

The other end of the head stand 30 is another guide shaft 13
It is slidably guided by.

That is, on the free end side of the head stand 30, as shown in FIG. 5C, a shaft 33 is provided which projects downward and rotatably supports a vertical roller 32. A spring 34 is mounted between the shaft 33 and the roller 32, giving the roller 32 the ability to move upward.

Further, the shaft 33 is attached to the head stand 30 by means of a screw 35.
One end of a leaf spring 36 is fixed to the upper side of the head stand 30 by this screw 35.

A roller 37 is rotatably fitted into an opening 30a formed in the head stand 30, the upper side of which is covered by the leaf spring 36, in a state perpendicular to the guide shaft 13.

Therefore, the guide shaft 13 is connected to the vertical roller 32.
It is held elastically between the slope of the roller 30 and the roller 30, and is slidably attached to the guide shaft 13.

The shaft 1 that guides the movement of the head stand 30 in this way
2 and 13 are provided with bearing members that utilize rotational friction caused by linear bearings and rollers, so the friction is extremely low, and the head stand can be moved much more smoothly than with bearings that utilize sliding friction.

Therefore, a small, low-power, inexpensive motor can be used as the pulse motor 8.

Of course, as shown in FIG. 5B, the guide shaft 12 is guided by a bearing member 38 that utilizes sliding friction, and the bearing member 38 is made of an expensive but extremely wear-resistant material, such as ruby. If you use something like this, you can use an inexpensive pulse motor as well.

Further, a spring 39 is stretched between the head stand 30 and the protruding piece 9, giving the head stand 30 a tendency to move toward the rotating shaft 20 side.

This head stand 30 is arranged above the cam 26, and one end of a lever 40 is rotatably supported on the back surface of the head 30 by a screw 41.

A spring 42 is stretched between the other end of the lever 40 and the head stand 30.
1 is given a rotational habit in the counterclockwise direction in FIG.

A roller 44 is rotatably supported on the lower surface of this lever 41 via a pin 43, and this roller 44 is in contact with the cam surface of the cam 26.

By the way, as shown in FIG. 6, the cam 26 has a spiral shape as a whole and has a large number of serrated cam surfaces. has 40 corresponding cam parts.

In Fig. 6, each cam part is set so that the radius indicated by the symbol RO is the maximum radius, and the radius indicated by R39 is the minimum radius. The magnetic head can be moved up to the track.

A pulse motor 8 rotates this cam, and its rotation is transmitted via gears 14, 15, and 27.

In reality, the pulse motor 8 is set to rotate 18 degrees when one driving pulse is input to the pulse motor 8, and when a pulse with a positive phase is applied, the motor rotates clockwise, and when a pulse with an opposite phase is applied, the motor rotates clockwise. If you add , it will rotate to the left.

Also, when the pulse motor 8 rotates 18 degrees, the gear 2
The gear ratio of each gear 14, 15, 27 is set so that the rotation angle 7 rotates by 6 degrees, and 40 cam portions with radii of RO to R39 are formed within this 6 degree range.

Therefore, for every 6° rotation of the cam, the magnetic head will move by one track, the specific amount of movement is 0.12 mm, and the total width of all 40 tracks is approximately 5 mm.

On the other hand, as shown in FIG. 24, an adjusting screw 45 is screwed into a bent portion 30a which is provided midway in the longitudinal direction of the head stand 30. As shown in FIG.

The tip of this adjustment screw 45 is shown in Fig. 24 (A, B).
As shown in FIG.
The position of can be adjusted.

Further, a rectangular opening 30b is formed in the middle of the head stand 30 in the longitudinal direction, and a magnetic head 47 is disposed within this with a support member 46 interposed therebetween.

An arc-shaped plate spring 49 is provided between one end of the support member 46 and a protruding piece 48 protruding from one end of the opening 30b.
is loaded, and the tip of the adjustment screw 51 screwed into the protrusion 50 protruding from the other end of the opening 30b is in contact with the side edge of the support member 46 on the side opposite to the spring 49. There is.

Therefore, by turning the adjustment screw 51, the support member 46
The position of the magnetic head 47 can be adjusted.

This adjustment screw 51 allows the center of the magnetic head to be adjusted correctly with respect to the center of the magnetic disk.

After adjusting the position correctly with the adjustment screw 51, the support member 46 is attached to the head stand 3 via the screw 52.
It is sufficient to completely fix it to 0.

By the way, brackets 53, 53 are provided protruding from the end of the head stand 30 on the guide shaft 12 side.
Using these brackets 53, the part arm 5
One end of 4 is rotatably supported via a pin 55.

A torsion coil spring 56 is wound around the pin 55, giving the arm 54 the ability to rotate clockwise in FIG.

The tip of the pad arm 54 extends above the magnetic head 47, and an adjustment screw 57 is screwed into the tip in correspondence with the magnetic head 47, and a pad 58 for holding the magnetic disk is provided at the bottom end. ing.

Therefore, by rotating the screw 57, the parallelism between the pad 58 and the magnetic head 47 and the pad pressure can be adjusted.

On the other hand, a control plate 59 is integrally provided on the lower side of the gear 27, and a protrusion 59a is protruded from a part of the control plate 59, and a notch 59b is formed at the base of the protrusion 59a. .

A lever 61 is rotatably supported on the bottom plate 6 on the side of the control plate 59 via a pin 60. Protrusions 61a and 61b are formed at one end of the lever 61 and spaced apart by a predetermined distance, and these protrusions 61a and 61b are always in contact with the outer peripheral surface of the control plate 59.

The other end of the lever 61 is elongated,
It faces toward a position that closes the upper side of a notch 6a formed on the near side edge of the bottom plate 6. and,
A sensor 62 is arranged facing the notch 6a. This sensor 62 is composed of, for example, a light emitting element and a light receiving element, and constantly receives reflected light from the lower surface of one end of the lever 61 to monitor the presence or absence of the lever 61.

By the way, the mounting position of the lever 61 and the protrusion 59
The following relationship exists between a and the cam portion of the cam 26 having the maximum radius RO.

That is, when the roller 44 reaches the cam portion with the maximum radius RO, the protrusion 59a touches the protrusion 61b of the lever 61.
It is set in a positional relationship that allows it to engage with.

Therefore, as shown in FIG.
When it is in the cam part of RI, the protrusion 61 of the lever 61
b is not in contact with the protrusion 59a, and one end of the lever 61 is in a state where the upper part of the sensor 62 is closed.

In this state, the protrusions 61a and 61b are connected to the control plate 59.
The lever 61 does not rotate.

However, the cam 26 is moved by the pulse motor 8.
When the roller 44 is rotated by one extra step, the roller 44 rides on the cam portion having the maximum radius RO, and the magnetic head 47, together with the head stand 30, corresponds to the outermost track position.

At this time, as shown in FIG. 7, the protrusion 59a contacts the protrusion 61b of the lever 61, the lever 61 is rotated counterclockwise in the figure, and the protrusion 61b is attached to the notch 59.
Insert into b. At this time, one end of the lever 61 is separated from the upper side of the sensor 62 as shown in FIG. 7, the sensor 62 is turned off, and it is detected that the magnetic head has reached the outermost track.

Therefore, if you set the outermost track as the 0 track so that this position can be reliably detected by the mechanism described above, and set it so that the magnetic head always reaches this position when the power is turned on, it is possible to The head position at corresponds to the 0 track, and if a pulse is applied to the pulse motor 8 from this position, the head will move to the 5th track for 5 pulses and to the 10th track for 10 pulses, so the track position can be freely selected. can.

The current position of the magnetic head with respect to these pulse inputs may be stored in the memory of the digital processing system.

By the way, the specific specifications between the control plate 59 and the lever 61 are as follows.

That is, as shown in FIG.
= 15 mm, and the rotation angle of 1 step α = 6 degrees, the movement distance of the peripheral edge of the control plate 59 δ = tan 6 degrees × 15 mm = 1.6 mm
It is.

Also, the distance B from the pin 60 to the tip of the lever 61 = 5 mm, and the distance A from the pin 60 to the rear end = 13
mm, the moving distance of the rear end of the lever 61 is δ ₁ , and the rotation angle is α′, α′=15/5×6°=18°, δ ₁ ≒tan18°×13mm≒4.2mm.

Therefore, when the peripheral edge of the control plate 59 rotates 1.6 mm, the lever ratio of the lever 61 is 3, so the lever 61
rotates approximately 18°.

As a result, the outer end of the lever 61 is rotated by 4.2 mm, and if the size of the sensor 62 is 3 mm, it is possible to sufficiently open and close the sensor surface.

Of course, if the sensitivity of the sensor 62 itself is increased, movement of about 1.6 mm of the protrusion 59a itself can be detected sufficiently, but movement of the control board can be easily and inexpensively detected by using the lever as described above. .

If such a lever is used, the rotation of the control plate 61 and therefore the cam 26 can be detected outside where other parts are present, so a detection mechanism that is less subject to space constraints can be obtained.

By the way, a magnetic disk cassette is attached to a coupler 22 provided at the upper end of the rotating shaft 20.

Most of this magnetic disk cassette is made of synthetic resin except for the center hub.

On the other hand, since most of the drive mechanism side of the magnetic disk is made of metal, it is affected by thermal expansion.

The details are as follows.

That is, in FIG. 24A, the distance from the center of the rotating shaft 20 to the center of the magnetic head 47, that is, a certain track, is l ₁ , the distance between the periphery of the center hub 63 and the center of the rotating shaft 20 is l ₂ , and the center If the distance from the periphery of the hub 63 to the track is _l3 , the _l2 part is metal and the _l3 part is synthetic resin. Specifically, if _l1 = 20 mm and _l2 = 8 mm, _l3 is 12.
mm.

On the other hand, if the distance from the center of the rotating shaft 20 to the track on the drive side is L ₁ , then the content is the distance from the center of the rotating shaft 20 to the periphery of the boss 28.
L ₂ , distance L ₃ from the boss 28 to the periphery of the cam 26,
This is the total distance _L4 from the periphery of the cam 26 to the track, and each part is made of metal.

Therefore, if L ₂ = 8 mm and L ₄ = 1.5 mm, L ₁ = 200
mm, so L ₃ =20-8-1.5=10.5 mm.

Now, if the error between L ₁ and l ₁ is set to zero at a temperature of 25°C, and the temperature rises by 20°C to 45°C, the following results will be obtained.

In other words, the linear expansion coefficient of metal is 16×10 ^-6 mm/℃,
The linear expansion coefficient of the synthetic resin film is 17×10 ^-5 mm/℃
Then, when l ₁ and L ₁ are applied to l ₁ (1+αt)−δ, it becomes as follows.

l ₁ = l ₂ + l ₃ = (8 + 8 × 20 × 16 × 10 ^-6 ) + (12 + 12 × 20 × 17 × 10 ^-5 ) = 20.043 mm L ₁ = L ₁ + L ₂ + L ₃ = (8 + 8 × 20 × 16 ×10 ^-6 ) + (1.5 + 1.5 × 20 × 16 × 10 ^-6 ) + (10.5 + 10.5 × 20 × 16 × 10 ^-6 ) = 20.006 mm In other words, when the temperature increases by 20°C, L ₁ and l ₁ The difference is
The difference is 20.043-20.006=37 μm, and the information on the magnetic disk cannot be read accurately.

Therefore, in the present invention, when the cam 26 is made of a synthetic resin having substantially the same linear expansion coefficient as the magnetic disk 64, _L1 becomes as follows.

L ₁ = (8 + 8 × 20 × 16 × 10 ^-6 ) + (1.5 + 1.5 × 20 × 16 × 10 ^-6 ) + (10.5 + 10.5 × 20 × 17 × 10 ^-5 ) = 20.038 mm L ₁ and l ₁ by changing the material
The difference is 20.043−20.038=5 μm.

Therefore, the influence of thermal expansion can be sufficiently reduced.

In the present invention, the magnetic head 47 and the roller 44
The center position can be determined by an adjustment screw 45.

Therefore, _L1 can be accurately set to 20 mm while observing the position of the magnetic head 47 using a microscope or the like.

FIG. 24B shows that the positions of the centers of the magnetic head and roller 44 have shifted by an amount δ.

Also, since the cam 26 is rotatable, the boss 17 and the boss 28 are rotated as shown in FIG. 24A.
There is a gap of δ ₂ between them.

Therefore, when the cam 26 rotates, the bosses 17 and 28
The gaps δ ₁ and δ ₂ between them are constantly changing, and the changes are directly
Affects L ₁ .

In order to eliminate this influence, in the present invention, a spring 39 is stretched between the head stand 30 and the protrusion so that the gap δ ₁ between the bosses 17 and 28 on the magnetic head side is constantly reduced to zero. 30 as constant boss 2
8 side, and is pressed against one side by a spring 42 so that the magnetic head position does not deviate from the track.

On the other hand, the rotating shaft 20 extends below the chassis 1, and a member constituting a motor is attached between it and a printed circuit board 65 fixed to the lower side of the chassis 1.

That is, the coil 6 is provided on the bottom surface of the printed circuit board 1.
5a is fixed by soldering.

On the other hand, a boss 66 is fixed to the lower end of the rotating shaft 20, and a dish-shaped yoke 68 and a gear 69 are fixed to the boss 66 by screws 67.

A ring-shaped permanent magnet 70 is fixed to the upper surface of the yoke 68, facing the coil 65a.

Further, a non-reflection plate 71 is fixed to the outer circumference of the yoke 68 and generates one pulse when the yoke rotates once, and a sensor 72 for detecting this is fixed to the printed circuit board 65 side.

Since the yoke 68 is made of nickel plating or the like, the sensor 72 consists of a light emitting element and a light receiving element.
The non-reflection plate 71 can be detected reliably, and this signal can be used as an index signal.

On the other hand, the sensor indicated by reference numeral 73 is fixed to the printed circuit board 65 side, and has a permanent magnet 74 and a yoke 75 continuous thereto.The yoke 75 faces near the gear 69 as shown in FIG. has been done.

In FIGS. 1 and 3, the reference numeral 76 indicates an electronic component such as an LSI, and the reference numeral 77 indicates a screw for fixing the printed circuit board 65 to the chassis 1.

By the way, the gear 69 is made of iron-based material and has a large diameter, and when the tips of the teeth approach the yoke 75, a change in magnetic flux occurs and a current flows through the coil on the sensor 73 side, which can be taken out as a signal. I can do it.

The above-mentioned coil 65a and the permanent magnet 70 side constitute a motor for rotating the magnetic disk.

By the way, this motor is set to rotate one revolution in 200ms.

Then, in order to be able to rotate at a constant speed without wobbling during one rotation of 200 ms, the 200 ms is divided into small parts so that accurate rotation control can be performed.

In other words, the diameter of gear 69 is 50 mm, the module is 0.25, and the number of teeth is 200, so 200 m
Changes in rotation are monitored by the sensor 73 at intervals of s÷200=1 ms.

The printed circuit board 65 is a thin insulating board and is fixed to the iron chassis 1, and the magnetic flux generated by energizing the integrally provided coil 65a is formed between the chassis 1 and the yoke 68. The permanent magnet 70, and thus the yoke 68 and gear 69, are rotated through the magnetic circuit.

By fixing the printed circuit board 65 to the iron chassis 1 in this manner, it becomes possible to narrow the distance between the permanent magnet and the chassis, and the efficiency of the magnetic circuit is improved.

Furthermore, if the chassis 1 is made of an iron-based printed board, the thickness of the motor portion can be reduced by the thickness of the printed circuit board 65 constituting the motor, and the number of parts can also be reduced.

By the way, since the permanent magnet 70 is given a force to be attracted to the chassis 1 side, the inner ring of the lower bearing 19 is pressed upward by the boss 66, so that it absorbs the play of the bearing 19 and moves together with the upper bearing 19. Shaking of the rotating shaft 20 can be prevented.

On the other hand, the boss 17 fixed to the chassis 1 side
Since the inner and outer diameters are machined at the same time based on the fixing part to the chassis 1, the inner and outer diameters can be machined to about 1 to 2 μm.

Due to this machining accuracy and the absorption of the backlash of the bearing 19, the runout of the rotating shaft 20 including the boss 17 is reduced.
It can be maintained within 5 μm.

This concludes the explanation of the drive mechanism section, and then the cassette mounting mechanism section will be explained.

The cassette mounting mechanism employs a structure as shown in FIGS. 8 to 16.

That is, what is indicated by the reference numeral 78 in the figure is a sliding frame that is open downward and forward and backward.

Rollers 79 are rotatably supported on both sides of the slide frame 78, and these rollers 79 are slidable and rotatable in the horizontal long holes 4 formed in the side plates 2, 2 of the chassis 1. is mated to.

Openings 78a are formed at the left and right upper end corners of this slide frame 78;
A projecting piece 78b integrally projects from the upper surface of the slide frame 78, passing above the slide frame 78a. This protrusion 78
A spring 80 is stretched between the protrusion 2a protruding from the side wall of the chassis 1 and the protrusion 2a.

Therefore, the slide frame 78 is given a force in the direction of protruding from the chassis 1 toward the front side.

A roller 81 is rotatably supported on protrusions protruding from the lower ends of both side plates of the slide frame 78, and can be slidably moved on the chassis 1 via the roller 81.

A protrusion 78c protruding from one end of the slide frame 78
A push button 82 is fixed to.

Further, two parallel oblique holes 83 are formed in the left and right side plates of the slide frame 78.

A slide plate 84 is slidably disposed on the left and right inner surfaces of the slide frame 78.

The slide plate 84 is formed in a rectangular shape,
Its lower end is in contact with a small diameter shaft portion 81a of the roller 81 which is in contact with the bottom plate 6 of the chassis 1.

A protrusion 84a is provided at the upper end of this slide plate 84, and this protrusion 84 is connected to the slide frame 7.
It fits into the opening 78a of No. 8 and serves as a guide.

Furthermore, a bent portion 84b that is bent inward is formed at the tip of the slide plate 84.

Furthermore, a substantially L-shaped opening 85 is formed in the slide plate 84 at a position substantially corresponding to the elongated hole 83 of the slide frame 78.

A projecting piece 84c is provided on the inside of the tip of the slide plate 84, and this projecting piece 84c and the slide frame 7
A spring 8b is stretched between the spring 8 and the spring 8.

Incidentally, a cassette guide 87 is arranged below the slide frame 78.

The cassette guide 87 is formed as a flat frame body, and rail portions 87a are formed on the left and right sides thereof to guide the cassette.

Furthermore, protrusions 88 are provided on the left and right sides of the cassette guide 87.
A pin 89 is protruded from each protruding piece 88, and a roller 90 is attached to these pins 89.
is rotatably supported.

Each roller 90 is rotatably fitted into the slide plate 84, the opening 85 of the slide frame 78, and the elongated hole 83.

Further, an opening 87b is formed in the center of the upper surface of the cassette guide 87, and a frame 91 is integrally provided across the opening 87b. A hub retainer 92 is attached.

Furthermore, an opening 87c into which the magnetic head is fitted is formed on the side of the opening 87b.

As described above, the slide frame 78 and slide plate 8
4. The cassette mounting mechanism is composed of three members: the cassette guide 87.

Next, the operation of this cassette mounting mechanism will be explained.

Before the magnetic disk cassette 93 is installed, the slide frame 78 is moved to the right in FIGS. 8 and 13 by the tensile force of the spring 80.

In this state, the roller 90 is within the guide groove 3 and the elongated hole 83 is closed as shown in FIG.
The opening 85 is located at the upper end of the L-shaped opening 85, and is located above the stepped portion 85a of the L-shaped opening 85.

That is, the roller 90 has the guide groove 3 and the elongated hole 8.
3. It is regulated by the opening 85.

The slide plate 84 is also pulled to the right in FIG. 13 by the spring 86, and the cassette guide 87 is positioned above the step 85a and is ready to receive a cassette.

In this state, move the cassette 93 to the cassette guide 8.
When the cassette 93 is fitted into the rail portion 87a of No. 7, the cassette 93 is guided by the rail portion 87a and guided to the back.

Eventually, the tip of the cassette 93 will touch the slide plate 8.
4, the slide plate 8
4 is moved forward against the tensile force of the spring 86.

Then, as the slide plate 84 moves, the opening 85 also moves, so that the step 85a of the opening 85 within the guide groove 3 moves as shown in FIGS. 12A and 12C.
The roller 90, which had been located at the opening 85, falls toward the vertical portion of the opening 85, and is guided below the guide groove 3 and the vertical portion of the opening 85, as shown in FIGS. 12B and 12D.

That is, the cassette 93 is connected to the cassette guide 8.
7 and move downward.

By the way, by this cassette insertion operation, the roller 90 moves from the upper end of the elongated hole 83, as shown in FIG. 12E, to the lower part of the elongated hole 83, as shown in FIG. 12F.

During this movement, the roller 90 pushes the right side edge of the long hole 83, so the slide frame 78 is moved a predetermined distance to the right as shown in FIG.

When the cassette guide 87 descends together with the cassette 93 in this way, the protrusion 7a of the positioning pin 7 having the protrusion 7a is fitted into the positioning hole 93a of the cassette 93, and the upper end of the pin 7 without the protrusion 7a is attached to the cassette. supports and positions the cassette in contact with the bottom surface of the cassette. This state is shown in FIG.

At this time, as shown in FIG. 11, the coupler 22 is fitted into the hub 95 located at the center of the magnetic disk 94, and the pin 23 is fitted into the positioning hole 96 formed in the hub 95. Further, the upper surface of the hub 95 is held down by a hub presser 92.

This mounting operation is performed while the rotating shaft 20 is being rotated.

When the cassette 93 is set in this manner, magnetic recording and reproduction are performed.

On the other hand, if it is desired to take out the cassette 93, the push button 82 is pressed and the slide frame 78 moves forward. Then, the periphery of the inclined elongated hole 83 becomes the roller 9.
0, the roller 90 is pushed up, and the cassette guide 87 is also pushed up, returning to its original position.

When the cassette guide 87 rises and the roller 90 also rises, it is located above the opening 85, so the slide plate 84 moves to the right as shown in FIG. The stepped portion 8 is in a state of being moved to the horizontal portion of the portion 85.
Get on top of 5a. Due to this movement of the slide plate 84, the bent portion 84b pushes the cassette 93, so that the cassette 93 is pushed forward from the end of the cassette guide 87 and can be taken out.

By the way, the slide frame 78, the slide plate 84,
The cassette guide 87 is disposed inside the side plates 2, 2 of the chassis 1 in an assembled state as shown in FIG. 79b allows for easy assembly by simply fixing to the side surface of the slide frame 87. The patch arm 54 may be attached to the head stand 30 side last.

Incidentally, FIG. 19A shows a block diagram of the control circuit.

The magnetic disk device according to the present invention is controlled by a computer 100. This computer 1
00 and the magnetic disk device side are connected by electric wires, and the input and output lines are connected by approximately 34 electric wires.

These 34 input/output lines are all processed with digital signals.

On the other hand, the control circuit on the magnetic disk device side
As shown in Figure A, the computer 100 can be roughly divided into
A digital processing circuit 101, such as a pulse motor drive circuit, is used to connect the magnetic head to the magnetic disk drive and amplify and digitize the outputs of various sensors, or to position the magnetic head on a predetermined track. It is configured.

This circuit 101 includes a read amplifier 102 for amplifying the signal read out from the magnetic head, a write amplifier 103, and a read/write switch 1.
04. An index amplifier 105 that generates one pulse signal when the magnetic disk rotates once, a track position detection amplifier 106 for detecting the track position of the magnetic head, a motor drive circuit 107 for rotating the magnetic disk, etc. are connected. has been done.

A speed control circuit 108 is connected to the motor drive circuit 107 for controlling the rotation speed of the motor, and is connected to the motor drive circuit 107 through signal lines 109 and 110 from the digital processing circuit 101 to control the speed as described later. Control takes place.

Further, the reference numeral 111 indicates an amplifier for monitoring the motor rotation speed.

What is indicated by the reference numeral 112 is a television.

By the way, based on the above-mentioned circuit configuration, in the present invention, in addition to performing general recording and playback at the same disk rotation speed, it is possible to perform high-density recording and to improve reliability. A structure is adopted that changes the motor rotation speed during playback.

That is, first, information to be recorded is sent from the computer 100 to the digital processing circuit 10 as a command.
1, the circuit 101 switches to the changeover switch 10.
A signal is input to the write amplifier 1 to switch the magnetic head from the playback mode to the recording mode.
03 is in the operating state.

In addition, the speed control circuit 10
After commanding 8 to perform low speed rotation operation, the amplifier 111
It is confirmed that the signal interval and the speed control interval time agree with each other, and it is confirmed that it is in a low speed rotation state, and a recording signal from the computer 100 is inputted to record information on the magnetic disk.

Conversely, when a playback command is issued from the computer side, the read/write switch 104 is switched to the read side, the read amplifier 102 is activated, the speed control circuit 108 is set to high speed mode via the signal line 109, and the amplifier 111 is activated. After confirming that the motor is in a high-speed rotation state, reading of the record is started and input to the computer 100.

Further, if it is desired to make the rotation speed the same during recording and reproduction, processing can be done by setting the reference frequency for setting the reference high speed rotation of the speed control circuit 108 to the same frequency as the low speed rotation speed.

Figure 19B shows the rotation speed of the magnetic disk at 300 rpm.
It shows the output characteristics when measuring the output of the magnetic head when changing the speed from 1 to 600 rpm to read information.

Recording frequency f = 125kHz, disk rotation speed
When the magnetic head output was set to 300 rpm, the magnetic head output was adjusted to 0.8 V, and when the rotation speed was doubled to 600 rpm using this point P as the origin, the magnetic head output was almost doubled at point Q.

In addition, when the recording frequency f is doubled to 250kHz, the magnetic recording density increases, so the origin output is about 25% lower than the P point, resulting in an output at the S point.If the rotational speed is doubled in this state, the S point is reached. On the other hand, point R, which has about twice the output, was obtained.

Based on this output characteristic, the magnetic disk is rotated to 300rpm.
When rotating at a frequency of 250kHz and performing magnetic recording at a frequency of 250kHz, when played back at that rotational speed, the voltage at point S is 0.6V.
However, as mentioned above, during playback, if the rotation speed was set to 600 rpm, an output of 1.2V at point R could be obtained.

In other words, a positive output voltage of 0.6V can be obtained, so even if there is a drop in output due to variations in the characteristics of the magnetic disk or due to loss in the magnetic circuit of the magnetic head, there is still enough output voltage for digital processing. It was possible to improve the reliability.

By the way, when recording the image signal of the television 112 on a magnetic disk, if the magnetic disk is set at 3600 rpm when recording one screen of a cathode ray tube, one field can be synchronized with one track, so one screen can be recorded.

Note that one screen means one field, and 1 second ÷ 60 screens = 16.7 ms.

By the way, the frequency at which TV images are recorded on a magnetic disk is 6.1MHz, so if the rotation speed is 3600rpm ÷ 300rpm = 12 times as explained in Figure 19B, the output should increase, but the recording frequency is 6.1MHz ÷ 250kHz = 24 times, the recording density increases and the amplifier output becomes approximately 0.4 to 0.5V. Therefore, recording and reproducing TV images on a magnetic disk can be reliably performed by rotating the disk at high speed.

Incidentally, the electronic components constituting the control circuit shown in FIG. 19A are mounted on three boards as shown in FIGS. 17 and 18.

That is, the printed circuit boards 65 and 11 described above
It is 3,114.

The printed circuit board 65 is equipped with an index, a track position detection circuit, a motor drive circuit, and the like.

Further, the board 113 is equipped with a read/write switch for the magnetic head, and a read/write amplifier, and the board 114 is equipped with an interface-related circuit for processing signals from each board 65, 113. be.

Further, a connector 115 is provided on each of the boards 65 and 113, and a connector 116 coupled to these is provided on the board 114 side so that the boards can be easily connected.

As shown in Figure 18, each board is attached to the top, bottom, and side surfaces of the chassis, so electrical signals can be easily adjusted and checked from outside the chassis. It can be easily repaired by replacing it.

By the way, magnetic disk devices are used as storage devices in computers, but in this case there are parts around the device that generate strong magnetic fields, such as cathode ray tubes, power transformers, and motors, so it is necessary to protect the device from these magnetic fields. be.

Therefore, in the present invention, the chassis 1 is formed into a U-shape, and its upper surface and side surfaces are made of an iron slide frame 7.
8. It is covered by a slide plate 84 and a cassette guide 87 to block external magnetic fields and has a structure with a large magnetic shielding effect.

FIGS. 20A to 20D explain the tracks of a magnetic disk, and although eight tracks are shown in the figures, in reality, 40 tracks can be recorded.

FIG. 20B shows an enlarged view of tracks [0 to 2], where the track width a is 50 μm, the track interval b is 70 μm, and the track pitch is a+b=120 μm.
It is.

In this way, when the track interval b is larger than the track width, if it is possible to record between the tracks, the 40 tracks can be increased to 80, and the recording capacity can be doubled.

This state of doubling the capacity is the second state.
Shown in Figure 0C.

In Figure 20C, a=50μm, b=10μm,
The track pitch is a+b=60 μm.

By the way, when the track spacing is reduced in this way, magnetic recording interference occurs between adjacent tracks.

Therefore, in the present invention, as shown in FIG. 20D, a method is adopted in which magnetic recording is performed by using two azimuth heads and alternating recording directions in different directions.

On the other hand, with respect to the magnetic disk shown in FIG. 20D, the magnetic head 47 was shifted from the outer circumference toward the inner circumference at intervals of 10 μm and the reproduction output was measured, and the results were as shown in FIG. 21A.

This playback output voltage is the measured output of the read amplifier 102, and finally this playback output voltage is input to a digital processing circuit to achieve a TTL level of 5V.
The signal is shaped into a peak-to-peak pulse and connected to a computer, etc.

Therefore, when inputting the output of Figure 21A to the digital processing circuit, the input level was set to 0.4V, and the input voltage was set to generate a pulse if the voltage was 0.4V or higher, and not to generate a pulse if it was lower than that. Then, the amount of deviation between the center of the track and the magnetic head is the 21st
As shown in Figure A, a normal digital signal is generated even if there is a deviation of ±25 μm.

Therefore, the total amount of dimensional deviation due to vibration of the motor shaft, error in the radius of the cam 26, temperature, expansion and contraction of the magnetic disk due to humidity, etc. is allowed to be up to ±25 μm.

On the other hand, FIG. 21B shows the output when the double density track shown in FIG. 20C is reproduced.

In FIG. 21B, curve A shows the output characteristics of track [0] when no magnetic recording is performed on track [1], and curve B shows the output characteristics of track [0].
This figure shows the measured characteristics of the output of track [1] when magnetic recording is not performed on the track [1].

When information is recorded on tracks [0] and [1] and the magnetic head is moved from the track [0] direction to the track [1] direction for measurement, an output as shown by curve C between curves A and B is generated. is played.

In other words, information interference occurs.

When we measure the voltage in the shaded area surrounded by curves A, B, and C, we find that curves A and B are not completely summed to form curve C, but that other noise components are mixed in. Ru.

Therefore, the portion of curve C does not provide accurate information.

In such a case, as shown in Fig. 21B, the limit for the amount of deviation between the track and the magnetic head is about 1/2 ± 12 μm compared to Fig. 21A, and the input level to the digital circuit is set to 0.65V. It will have to be done.

That is, if the amount of information is to be doubled using the recording method shown in FIG. 20C, the dimensional accuracy must be more than doubled, which requires highly accurate and expensive parts.

Therefore, in the present invention, a recording method as shown in FIG. 20D described above is adopted.

That is, recording was performed using a head gap that alternately faced different directions such as θ ₁ =θ ₂ for each adjacent track.

Note that θ ₁ =θ ₂ =10 degrees.

The structure of such a magnetic head is shown in FIG.

In Fig. 22, the core halves indicated by numerals 117 and 118 constitute one of the magnetic head cores, and a gap having an angle of θ ₁ is located at the abutting portion of the two core halves.
G ₁ is formed.

Further, reference numerals 119 and 120 indicate core halves constituting the other magnetic core, and a gap G ₂ having an angle of θ ₂ is formed at the abutting portion of the two core halves.

These cores are supported by a core support 121, and a coil 122 is wound around the core halves 117, 119.

The core support 121 is made of a glass material 123 that bonds between the cores or a resin containing a large amount of a glass material having an expansion coefficient almost equal to the expansion coefficient of Sendust, which is a core material, and is resistant to environmental changes such as vibration and temperature. The structure is said to be sufficiently durable.

Now, after magnetically recording the same information on tracks [0 to 2], move the head consisting of the core halves 117 and 118 in FIG. 22 from the outer circumferential direction to the inner circumferential direction.
When the reproduced output voltage was measured by moving in steps of 10 μm, an output characteristic of curve A shown in FIG. 21C was obtained.

In the characteristic shown by curve A, the output voltage is small in the track [1] portion because the track [1] is recorded by a magnetic head having an inclined gap of θ ₂ .

That is, since the gap at which track [1] was recorded and the gap at which the head is currently passing are different by 20 degrees, the output is small and the noise component increases.

Conversely, when the head side consisting of the core halves 119 and 120 is moved from the outer circumferential direction to the inner circumferential direction of the track and the reproduction output is measured, an output as shown by the broken line B in FIG. 21C is obtained.

At this time, the optimum reproduction output voltage can be obtained in the track [1] portion.

In this way, for several digits at the track corner including 0, θ ₁
By performing magnetic recording and reproducing using an azimuth head having an inclined gap and a gap inclined by _θ2 at odd number digits, interference between magnetically recorded information between adjacent tracks is extremely reduced.

Therefore, if the input level is set to 0.4V, the amount of deviation between the recorded track and the magnetic head will be 25μ.
Up to m will be allowed.

In this way, high-density recording using magnetic heads with gap angles θ facing in opposite directions facilitates mechanical dimensional accuracy, and the simple mechanism facilitates design and increases the compatibility of magnetic recording media. become.

23A and 23B illustrate other structural examples of the magnetic head, and in this embodiment, the magnetic head 12
4, a pair of magnetic core halves 125 and 126 are arranged at a predetermined interval b, and a head stand 127 is arranged.
It is installed on.

The thickness a of the core halves 125 and 126 is 50 μm,
The interval b is 2.5 mm, and each coil is made of sendust and glass welded with a gap G = 0.1 μm.
28 is attached using a winding window 129.

When using a magnetic head with such a structure, the second
When recording as shown in Figure 0B, the core half 125 side records tracks [0 to 19], the other core half 126 records tracks [20 to 39],
You can take charge of regeneration.

Therefore, if such a magnetic head 124 is used,
To record and play back 40 tracks, the head stand 12 must be moved 20 steps by the pulse motor 8 to cover all 40 tracks.

In this case, the number of stages of the cam 26 may be 20 stages.

For example, in the case of a magnetic head with only one core, if you calculate the time required to change the track from [0 to 20], the speed characteristic of the pulse motor is
3ms is one track, so 20 x 3ms = 60m
It becomes s.

Also, even when the magnetic head arrives at the 20th track, the pulse motor 8 does not stop suddenly and vibrates slightly, so you have to wait until it stops before recording.
Need to play. Therefore, recording and playback cannot be started until approximately 70 ms have elapsed.

On the other hand, if the head shown in Fig. 23 is adopted,
After recording and playing back track [0], it is possible to immediately record and play back track [20] without waiting time.

In addition, a head with one core can record and play back tracks [0 to 39] in 3ms x 39+10
(Waiting time) = 127ms is required, whereas in the case of the head shown in Figure 23, it is 3ms x 19 + 10 (waiting time) =
Since it is 67mms, there is a difference of 60ms, which means that higher speed can be realized.

Next, a magnetic disk cassette applied to the magnetic disk device according to the present invention will be explained.

As shown in FIG. 25, the cassette 93 consists of upper and lower cassette halves 130, 131, between which a magnetic disk 94 having a center hub 95 is housed. Each cassette half has a center hub 95
A head window 133 is formed in each hole.

Further, the reference numeral 134 indicates an arrow to indicate a cassette attachment method, and the reference numeral 135 is a recessed portion on which a label 136 for writing a program name, etc. is pasted.

Further, reference numerals 137 and 138 indicate positioning holes into which the protrusion 7a at the upper end of the pin 7 is fitted.

By the way, the shutter 139 is fitted to the outside of the cassette halves 130 and 131 which are put together vertically, and has a U-shaped cross section, and is slidably fitted from the outside of the cassette so as to sandwich it therebetween. Ru.

At one end of the shutter 139 is a cassette half 13.
A projecting piece 141 is formed to be slidably fitted into a groove 140 formed on the upper surface of the 0 side.

Further, a bent portion 142 is formed facing the protrusion 141 and facing inward.

This bent portion 142 is fitted into grooves 143 and 144 formed in the upper and lower cassette halves, and guides the shutter 139.

In addition, the groove 144 of the lower cassette half 131
A pin 145 is protruded from the innermost end of the cassette half, and a spring 146 is stretched between the pin 145 and the bent portion 142 to pull the shutter 139 toward the center of the cassette half. It gives me the power to reach out.

Note that the grooves 14 of the cassette halves 130 and 131
Lower step portions 147 for guiding the bent portions 142 are formed along the side edges of the portions 3 and 144, respectively.

A quadrilateral recess 148 is formed on the outer surface of each cassette half 130, 131, with which the shutter 139 contacts.

Further, the reference numeral 149 is a shutter retainer.

Further, the reference numeral 150 is used to insert the cassette into the cassette guide 87.
This is a groove through which a bent portion 87d for opening a shutter protruding from the entrance end of the cassette when inserting a cassette is passed.

As shown in FIG.
a to open the shutter 139 with the head window 133 closed.

The closed state of the shutter is shown in FIGS. 26A and 26B, and the opened state is shown in FIGS. 26C and D.

Since the magnetic disk cassette used in the magnetic disk device of the present invention is constructed as described above, simply by inserting it into the cassette guide on the device side, the shutter, which is normally closed, is automatically opened and magnetic recording can be performed. Reproduction can be performed reliably.

[Effect] As is clear from the above description, according to the present invention, the magnetic disk mounting mechanism is configured to be mounted from the top of the chassis at the end of the assembly process, so that the mounting dimensions of the magnetic head can be reduced. and position adjustment can be performed in a wide space, and assembly work can be simplified.

[Brief explanation of the drawing]

The figures are for explaining one embodiment of the present invention, and FIG. 1 is an exploded perspective view of the disk and head drive mechanism;
Fig. 2 is a perspective view of the chassis with the head drive mechanism installed, Fig. 3 is a sectional view taken along the line A-A in Fig. 2, Fig. 4 is a sectional view taken along the line B-B in Fig. 2, and Fig. 5 is a sectional view taken along the line A-A in Fig. 2. Diagram A
5 is a sectional view showing the bearing structure of one side of the head stand.
Figure B is a sectional view showing another example of the bearing structure, Figure 5C
5 is a sectional view showing the other bearing structure of the head stand.
Figure D is a sectional view taken along the line C-C of Figure 5C, Figures 6 and 7.
The figures are explanatory diagrams showing the structure and operation of the cam structure and the track outermost circumference position detection mechanism, Fig. 8 is an exploded perspective view of the cassette mounting mechanism, Fig. 9 is a perspective view of the cassette mounting mechanism in the assembled state, and Fig. 10 The figure is a cross-sectional view of the cassette mounting mechanism immediately after inserting the cassette.
The figure is a cross-sectional view of the cassette loading mechanism in a fully loaded state, Figure 12 is an explanatory view showing the movement of the rollers during the cassette loading operation, and Figure 13 is a cross-sectional view of the cassette loading mechanism before the cassette is lowered. 14 is a sectional view of the cassette mounting mechanism after the cassette has been lowered, FIG. 15 is a perspective view showing the relationship between the cassette mounting mechanism and the chassis, and FIG. 16 is a perspective view of the chassis with the cassette mounting mechanism attached. , Fig. 17 is an explanatory diagram showing the arrangement of the board on which the control circuit is mounted, Fig. 18 is a side view of the chassis with the board mounted, Fig. 19A is a block diagram of the control circuit, and Fig. 19B is the media. Fig. 20A is an explanatory diagram of tracks of a magnetic disk, Fig. 20B is an explanatory diagram of coarsely recorded tracks, and Fig. 20C is an explanatory diagram of densely recorded tracks. FIG. 20D is an explanatory diagram of the track, FIG. 20D is an explanatory diagram of the recording method adopted by the present invention, and FIGS. 21A to C are FIG. 20B
22A is a plan view of the magnetic head, FIG. 22B is a sectional view taken along the line DD in FIG. 22A,
FIG. 23A is a plan view showing another example of the structure of the magnetic head, FIG. 23B is a sectional view taken along the line E--E of FIG. 23A,
FIGS. 24A and 24B are cross-sectional views and explanatory views explaining details of the track positioning mechanism, FIG. 25 is an exploded perspective view of the magnetic disk cassette, and FIGS. 26A and B are plan views of the cassette with the shutter closed. and a side view, Figures 26C and D are a plan view and side view with the shutter open, Figure 27 is an enlarged sectional view taken along the line FF in Figure 26A, and Figure 28 explains the opening operation of the shutter. FIG. DESCRIPTION OF SYMBOLS 1... Chassis, 30... Head stand, 47... Magnetic head, 87... Cassette guide, 93... Cassette.

Claims (1)

[Scope of Claims] 1. A chassis is formed by bending both side edges of a plate-like member into a substantially U-shape to form a flat part in the center and side plates on both sides thereof, with an opening at the top, and the chassis A disk cassette for storing the disk-shaped recording medium, the disk cassette comprising a spindle for rotating a loaded disk-shaped recording medium and a head drive mechanism for driving a head for recording or reproducing information on the recording medium, on a flat surface of the disk-shaped recording medium. a cassette guide that holds the disc cassette and is movable up and down between a first position where the disc cassette can be attached and removed and a mounting position where the disc-shaped recording medium in the disc cassette is mounted on the spindle;
The cassette guide is moved between the first position and the second position.
A cassette mounting mechanism assembly consisting of a slide member for moving up and down between the two positions, and a locking member for locking the cassette guide at the first position or the second position is attached to the opening above the chassis. A disk mounting device characterized in that the cassette guide can be attached to a guide groove formed in a side plate of the chassis by mounting the cassette guide from the side of the chassis.