JPS60109072A - Magnetic disk device - Google Patents

Abstract

PURPOSE:To shorten the stepping time of a magnetic head and to perform high- speed reproduction by providing magnetic heads for magnetic recording and reproduction to plural points of a magnetic disk at specific intervals. CONSTITUTION:When a cassette guide 87 is lowered together with a cassette 93, the projection 7a of a positioning pin 7 is fitted in the positioning pin 93a of the cassette 93 and the upper end of a pin 7 which does not has the projection 7a contacts the reverse surface of the cassette to support and position the cassette. At this time, a coupler 22 engages the hub 95 at the center part of the magnetic disk 94 and a pin 23 is fitted in the positioning hole 96 formed in the hub 95. The top surface of the hub 95 is pressed with a hub presser 92.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a magnetic disk device, and more particularly to a magnetic disk device in which the mounting of a magnetic head is improved in structure.

[Prior Art] Conventionally, two magnetic heads for magnetic recording and reproducing are provided separated by a predetermined distance. Therefore, the time it takes to step the magnetic head from the outermost track to the innermost track of the magnetic disk is shortened. It took a long time, and high-speed magnetic recording and reproduction could not be performed.

[Purpose] The present invention has been made to eliminate the above-mentioned conventional drawbacks.
It is an object of the present invention to provide a magnetic disk device configured to shorten the step time of a magnetic head and perform high-speed magnetic recording and reproducing.

[Example] Hereinafter, the present invention will be described in detail based on the example shown in the drawings.

The magnetic disk device according to the present invention is assembled with a chassis 1 as a reference. The chassis l is constructed as a U-shaped frame having left and right side plates 2, 2, each side plate 2.
Guide grooves 3, 3 are formed downward from the two side edges at opposing positions of the two. A cola projecting from the cassette guide side, which will be described later, is fitted into these guide grooves 3, 3.

In addition, a guide hole 4 is formed in a horizontal state between the guide grooves 3 and 3 at opposing positions of the side plates 2 and 2, and a guide hole 4 is formed in a horizontal state on the front side edge of the side plates 2 and A guide groove 5 is formed. These guide holes4. kite groove 5
A kite roller of a slide frame, which will be described later, is fitted inside.

On the other hand, on the bottom plate 6 of the chassis 1, there are 3
A wooden positioning pin 7 is provided protrudingly.

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

A pulse motor 8, which serves as a drive source for moving the &1 head, is fixed to one end side of the bottom plate 6 of the chassis via studs 8a, 8a, and a protrusion 9 cut and raised from the bottom plate 6 protrudes near the studs 8a. It is set up. A through hole 10 is formed in the projecting piece 9, and a through hole 11 is formed in one of the side plates 2 in a seven-sided configuration facing the through hole 10. These through holes 10,
A guide shaft 12 on which a head taking stand, which will be described later, is guided is horizontally mounted using the guide shaft 11 .

Further, on the near side of the chassis 1, another wooden guide bar 13 is horizontally suspended between the side plates 2 and 2 in parallel with the guide shaft 12.

First, a drive gear 14 is fixed to the lower side of the pulse smoke 8 at its protruding side N+, and this drive gear 1
4 are gears 15 and 11 rotatably supported on the bottom plate 6''2.
It's 2 go.

A through hole 16 is formed approximately in the center of the bottom plate 6, and a boss 17, which serves as a rotational drive mechanism for the magnetic disk, is disposed in the through hole 16.

As shown in FIG. 3, the boss 17 has a flange 17a on the outer periphery of its central part, and this flange 17a is stacked on one side of the bottom plate 6, the lower part of the boss 17 is fitted into the through hole 16, and the screw is inserted. 18 through the flange 17a.

A rotary shaft 2o is rotatably supported in the housing 17 via a pair of upper and lower bearings 19,19. A collar 21 is placed between the hair rings 19 below Jl. The outer ring of each bearing 19.19 is press-fitted into the housing 17.

A coupler 22 is fixed to two wheels of the rotating shaft 20.

The coupler 22 is fitted into the center hub of the magnetic tape cassette, and a positioning pin 23 is fitted into the flange 22a of the coupler so as to be movable 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.

A spring 25 is installed between the lower surface of the coupler 22 and the inner ring of the bearing 19 on the 1- side, and by pressing the inner ring downward, a relative positional shift is caused between the inner ring and the outer ring. This creates uniform contact between the inner and outer rings and the balls, eliminates looseness 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 the boss 28 with the cam 26 set to llff, or the gear 27 is meshed with the gear 15 to control the rotation of the pulse motor 8 via the cam 27. A tightening washer 29 is fitted on the outside of the boss 28 to prevent the cam 26 and the like from being removed.

On the other hand, what is shown in special photograph 3o is a head stand, which is formed into an elongated plate shape. One end of the head stand 3o is slidably fitted to the guide shaft 12 via a linear bearing 31.

The other end of the head stand 3o is slidably guided by another guide shaft 13.

That is, on the free end side of the head stand 3o, as shown in FIG. Rotate your eyes! There is a protruding support 33 for receiving II:b. A spring 34 is mounted between the foot 33 and the roller 32, and gives the roller 32 the ability to move like a car.

In addition, the 1lil+ 33 is attached to the head stand 3 by the screw 35.
One end of a leaf spring 36 is fixed to the menu side of the hend stand 30 by this screw 35.

The head stand 30 whose J-side is covered by this leaf spring 36
There is a shape 7J? perpendicular to the guide shaft 13 in the opening 30a formed in the opening 30a. A roller 37 is rotatably fitted therein.

Therefore, the shaft F-shaft 13 is elastically held between the body surface of the circular roller 32 and the roller 30, and is slidably mounted on the shaft F-shaft 13.

In this way, the shafts 12 and 13 that guide the movement of the head stand 30 use the rotational friction of the hair rings and rollers, and because they are interposed between members, the friction is extremely small, and it is much smoother than bearings that use sliding friction. The head stand can be moved.

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

However, as shown in FIG. 5(B), the guide member 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. For example, if ruby or the like is used, an inexpensive pulse motor can be used as well.

Also, a spring 39 is provided between the head stand 30 and the protruding piece 9.
is stretched, giving the head stand 30 the habit of moving toward the rotating shaft 20 side.

This head stand 30 is disposed on the "-" side of the forces 1 and 26, and is rotatably supported on the back surface of the head 30 by a pawl 41 at one end of a divider 40.

A spring 42 is stretched between the other end of the lever 40 and the head stand 30, and allows the lever 41 to rotate counterclockwise in FIG.

A roller 44 is attached to the lower surface of this 8-41 via a pin 43.
is rotatably supported, and this roller 44 is in contact with the force 1 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 not indicated by the symbol RO is the maximum radius and the radius indicated by R39 is the minimum radius, and is arranged from the outermost track of the magnetic disk to the innermost radius. The magnetic head can be moved to the surrounding trunk.

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 186 times when one driving pulse is input to the pulse motor 8. 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. When added, it rotates to the left.

Also, when pulse smoke 8 rotates 18 degrees, gear 27 or 6
The gear ratio of each gear 14, 15.27 is set so that it rotates by -C, and within this 6° radius, the radius is RO-R.
Forty 39 cam portions are formed.

Therefore, for every 6° rotation of the cam, the magnetic flux is l.
It now moves by 1-rack, and the overall movement amount is 0.12 mm, and the total width of all 40 trunks 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 in contact with a bent portion 40a formed on the free end side edge of the lever 40, as shown in FIG. 24 (A, B), and the position of the lever 41 can be adjusted by I can do that.

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 arcuate leaf spring 49 is elastically mounted between one end of the support member 46 and a protruding piece 48 protruding from one end of the opening 1-1 section 30b. protruding piece 5 protruding from
The tip of the adjustment screw 51 screwed into the support member 46
The spring 49 is in contact with the opposite side edge of the spring 49 .

Therefore, by turning the adjusting screw 51, the position of the support member 46 can be adjusted, and the position of the magnetic head 47 can also 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 properly adjusting its position with the adjustment screw 51, the support member 46 may be completely fixed to the head stand 30 via the screw 52.

Incidentally, brackets 53 and 53 are protruded from the end of the head stand 30 on the guide shaft 12 side, and using these brackets 53, one end of the putt arm 54 is rotatably supported via a pin 55. ing.

A torsion coil spring 56 is wound around the pin 55.
The putt arm 54 is given the habit of rotating in the forward direction in FIG.

The tip of the pad arm 54 extends toward one side of 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 pressing the magnetic disk is provided at the bottom end of the pad arm 54. It is provided.

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

On the other hand, a control plate 59 is integrally provided below the gear 27, and a protrusion 59a is protruded from a part of the control plate 59.
A notch 59b is formed at the base of this protrusion 5'9a.

A pin 6 is provided on the bottom plate 6 on the side of the control plate 59.
A lever 61 is rotatably supported on the shaft via the lever 61. At one end of this lever 61 there is a protrusion 61 spaced apart by a predetermined distance of 17 JI.
a, 61b are formed, and these protrusions 61a, 61
b is always in contact with the outer peripheral surface of the control plate 59.

The other end of the lever 61 is formed into an elongated shape, and faces a position that closes the J- side of the notch 6a formed at the front edge of the bottom plate 6. A sensor 62 is arranged facing the notch 6a. This sensor 62 consists 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.

Incidentally, there is the following relationship between the mounting position of the lever 61, the projection 59a, and the cam portion of the cam 26 having the maximum radius RO.

That is, when the roller 44 reaches the cam portion having the maximum radius RO, the positional relationship is set such that the projection 59a can engage with the projection 61b of the slider/head 61.

Therefore, as shown in FIG. 6, when the roller 44 is at the cam portion with radius RI, the projection 61b of the lever 61 is replaced by the projection 59a.
It is not in contact with the sensor 62, and one end of the lever 61 is in contact with the sensor 62.
One side is blocked.

In this state, the protrusions 61a and 61b are in contact with the peripheral surface of the control plate 59, allowing the lever 61 to rotate.

However, when the cam 26 is rotated an extra l step by the pulse motor 8, the roller 44 rides on the cam portion with the maximum radius RO, and the magnetic head 47 moves along with the head stand 30 to the outermost track 2. This will correspond to the location.

At this time, as shown in FIG.
The lever 61 is rotated in the counterclockwise direction in the figure, and the projection 61b is fitted into the notch 59b. At this time, one end of the lever 61 is separated from the "] side of the sensor 62 as shown in FIG. 7, the sensor 62 is turned off, and it is detected that the W air head has reached the outermost track.

Therefore, the outermost track is set as the O track, and this position is reliably detected by the above-mentioned mechanism.
If the magnetic head is set to reach this position when the power is turned on, the head position at the start will match the o track, and if pulses are applied to the pulse motor 8 from this position, 5 pulses will be 5 pulses. Track 1
'', if the head is moved to the 10th track with 10 pulses, the track position can be freely selected.

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

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

That is, as shown in FIG. 6, if the radius R of the control plate 59 is 15° and the rotation angle α of one step is 6°, the moving distance of the peripheral edge of the control plate 59 is δ= tan 6' x 15+nm.
=1.6mm.

Also, the force ratio fiB from the pin 60 of the lever 61 to the tip is
5mm, distance A from pin 60 to rear end = 13+nm,
If the moving distance of the rear end of the lever 61 is δl and the rotation angle is α', then α'=1515XEi°=186. 61 wheels 18' x 13mm', 4.2mm
becomes.

Therefore, when the peripheral edge of the control plate 59 rotates by 113 mm, the lever ratio of the lever 61 is 3. Therefore, the lever ratio of the lever 61 is approximately 18.
``Turn around.

As a result, the outer end of the lever 61 is rotated by 4.2 mm,
If the size of the sensor 62 is 311II11, the sensor surface can be opened and closed sufficiently.

Of course, if the sensitivity of the sensor 62 itself is increased, the protrusion 59a
My own 1. Movements of about E1mm can be detected sufficiently.
By using two levers, movement of the control plate can be detected easily and inexpensively.

If such a lever is used, the control plate 61 and therefore the cam 2
Since the rotation of 6 can be detected outside where other parts are present, it is possible to obtain a detection mechanism that is less subject to space constraints.

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 m% 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. 24(A), the distance from the center of the rotating shaft 20) 1 to the center of the magnetic head 47, that is, a certain track, is 11, and the distance between the periphery of the center hub 63 and the center of the rotating shaft 20 is 42, and the distance from the periphery of the center hub 63 to the track is 13, then 1. ．． The part 122 is metal, the part No 3 is synthetic resin, and specifically,
41 = 20mm.

, A'2=811111, then 13 becomes 12 mm.

- On the force and drive side, if the distance from the center of the rotating shaft 20 to the track is Ll, the contents are the distance L2 from the center of the rotating shaft 20 to the periphery of the post 28, and the distance from the post 28 to the cam 2
Each part is made of metal.

Therefore, if L2 = 8mm and L4 = 1.5mm, then L1 = 20mm, so L3 = 20-8
-1.5 = lO15II1mte.

Now, if the temperature is 25°C and you set the error between
In this case, the following results will be obtained.

In other words, the coefficient of linear expansion of metal is 18X l (1″6mm1
℃, the linear expansion coefficient of the synthetic resin film is 17X 10''
If 5mm/'C, then j! 1 + L l is 11 (
1+αt)−δ, it becomes as follows.

11=, ρ2 + , +13 = (8+8 X20X
1eX 10″6)+ (12+l2X20X17X
10u) = 20.043 mm Ll = L1 +L2 +L3 = (8+ 8 X 20X 16X 10℃) + (
1,5+1.5 X20'Xl6XI045)+ (1
0,5+ lo, 5x 20X 16X 10- )=
20.008mm In other words, if the temperature rises by 20℃, the difference between Ll and 11 will be 20
．． 043-20.006 = 37p, re goes out of order, and the information on the magnetic disk-L cannot be read accurately.

Therefore, in the present invention, the material of the cam 26 is
k made of synthetic resin with a linear expansion coefficient almost the same as 4.
Ll is as follows.

L 1 = (8+ 8 X20X IBXIO)+
(1,5+1.5X20X16X10'')+ (1
0.5+ +0.5X 20X 17X 1(1')
= 20.038mm That is, by changing the material of the cam, the difference between Ll and 11 becomes 20.043-20.038 = 5p, m.

Therefore, the influence of 8 expansion can be sufficiently reduced.

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

Therefore, by observing the position of the magnetic hand 47 using a microscope or the like, it is possible to accurately set the position to 20 nuo.

Th%24 Figure (B) shows that the positions of the centers of the magnetic head and roller 44 have shifted by δ.

Also, since the cam 26 is rotatable, the second
As shown in FIG. 4 (A), there is a gap of δ2 between the boss 17 and the hub 28.

Therefore, when the cam 26 rotates, the gaps δl and δ2 between the bosses 17 and 28 constantly change, and this change directly affects the clearances δl and δ2.

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 δ1 between the bosses 17 and 28 on the magnetic head side is constantly reduced to zero. The magnetic head is always drawn toward the boss 28 and 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 the members constituting the motor can be accessed between it and a printed circuit board 65 fixed to the lower side of the chassis 1.

That is, a coil 65a is fixed to the lower surface of the printed circuit board 1 at a half-length.

- 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 - side of the yoke 68 in a position 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 plated with nickel, the sensor 72 consisting of a light emitting element and a light receiving element has a non-reflective plate 71.
can be reliably detected, and this signal can be used as index number 44.

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

In FIGS. 1 and 3, numeral 94 76 indicates an electronic component such as an LSI, and 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 at 200 m5 per revolution.

Then, in order to be able to rotate at a constant speed without wobbling during one rotation of 200+ns, the area within 200 m5 is divided into small parts so that accurate rotation control can be performed.

In other words, since the diameter of the gear 69 is 50m+n, the module is 0.25, and the number of teeth is 200,
Changes in rotation are monitored by the sensor 73 at intervals of 200m5/200=Ims.

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. Through the magnetic circuit, the permanent magnet 70 and thus the yoke 68 . Gear 69 is rotated.

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

Furthermore, if the chassis l 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 in the -F direction by the boss 66, so that the bearing 1
It can absorb the backlash of the rotating shaft 20 and prevent the rotating shaft 20 from swinging together with the hair ring 19 on the second side.

On the other hand, since the inner and outer diameters of the boss 17 fixed to the chassis I are machined simultaneously based on the fixed part to the chassis I, the inner and outer diameters can be increased by about 1 to 2 gm.

By this machining accuracy and absorption of the backlash of the bearing 19, the runout of the rotating shaft 20 including the host 17 can be maintained within 5 pm.

This concludes the explanation of the drive mechanism section, and then the explanation of the force cera/mounting mechanism section will be given.

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 at the bottom and front and back.

Rollers 79 are rotatably supported on both sides of the slide frame 78, and these rollers 79 are attached to the chassis 1.
It is slidably and rotatably fitted into a horizontal elongated hole 4 formed in both side plates 2, 2.

An opening 78a is formed at the left and right upper end corners of the slide frame 78, and a protruding piece 78b projects from the two sides of the slide frame 78 as one piece through the upper side of the opening 78a. It is set up. A spring 80 is stretched between the protrusion 78b and a protrusion 2a protruding from the side wall of the chassis l.

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

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

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

Furthermore, the left and right side plates of the slide frame 78 have oblique long holes 8.
3 is formed in two places in the ilZ row.

A slide plate 8 is provided on the left and right inner surfaces of this slide frame 78.
4 are slidably arranged.

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

A protrusion 84a is provided on the second chain of the slide plate 84, and this protrusion 84 fits into the opening part 78a of the slide frame 78 and serves as a guide.

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

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

A protruding piece 84c is provided on the inside of the tip of the slide plate 84, and a spring 8b is stretched between the protruding piece 84c and the slide L78.

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

The cassette guide 87 is formed as a flat frame body, and on the left and right sides thereof there are rail portions 8.7 that guide the cassette.
a is formed.

In addition, the left and right protruding horns 188 of the cassette guide 87
Each of the protruding pieces 88 and pins 89 are protruded, and a roller 90 is rotatably supported on these pins 89.

Each roller 90 is connected to the slide plate 84. Slide frame 78
Opening [1 part 85. It is rotatably fitted into the elongated hole 83.

In addition, an opening 6687 is formed in the center flRL of the negative side of the cassette kite 87.
The frame body 91 is being pushed all the way across b, and the /\b presser 92 is firmly attached to the frame body 91.

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

The slide frame 781 described in 1-1 below. slide plate 84,
The three members of the cassette guide 87 constitute a cassette mounting mechanism.

Next, the operation of this 4% cassette loading machine will be explained.

Before the magnetic disk cassette 93 is installed, the slide frame 78 is at f5 due to the tensile force of the spring 8o.
It has moved to the right in Figure f3 and Figure 13.

In this state, the roller 9o is located in the guide groove 3 and in the two-ring portion of the elongated hole 83 as shown in FIG. 85a''2.

In other words, the roller 90 is inserted into the guide groove 3. It is in a state where it is regulated by the elongated hole 83 and the opening 85.

Furthermore, the slide plate 84 is also supported by the spring 86.
The cassette guide 87 is pulled to the right in Figure 3.
is in a position to receive a cassette in an upper position restricted by the stepped portion 85a.

In this state, when the cassette 93 is fitted into the rail portion g 7 a of the cassette guide 87, the cassette 93 is guided by the rail portion 87a and guided to the back.

Eventually, the tip of the cassette 93 comes into contact with the bent portion 84b at the tip of the slide plate 84, and the slide l' plate 84 is moved forward against the tensile force of the spring 86.

Then, as the slide plate 84 moves, the opening 85 also moves, as shown in FIGS. 12(A) and 12(C).
The roller 9o, which was located at the step 85a of the opening 85 in the kite groove 3, falls to the vertical side of the opening 85, as shown in FIGS. 12(B) and 12(D). , the guide groove 3 and the vertical portion of the opening 85.

That is, the cassette 93 moves downward together with the cassette guide 87.

By the way, due to this cassette insertion operation, the roller 90
ff5f 2
Move to the bottom of 3.

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.

In this way, the cassette guide 87 together with the cassette 93
When the pin 7a is lowered, 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 north end of the pin 7 without the protrusion 7a contacts the bottom surface of the cassette to support and position the cassette. Do the following. This state is shown in FIG.

At this time, as shown in FIG. 11, the coupler 22 is fitted into the hub 95 in the center of the magnetic disk 94, and the pin
is fitted into a positioning hole 96 formed in the hub 95. Further, two surfaces of the hub 95 are held down by a hub holder 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 peripheral edge of the inclined elongated hole 83 pushes the roller 90, so the roller 90 is pushed up and the cassette guide 87 is also pushed down.
- It is lifted and returns to its original position.

When the cassette guide 87 rises and the roller 90 also rises y1, it is located at the opening 85, so the slide plate 84 moves to the right as shown in FIG. 13 due to the tension of the spring 86. Then, the roller 90 moves to the horizontal portion of the opening 1'' portion 85 and rides on the stepped portion 85a''-. Due to this operation of the slide plate 84, the bending portion 84b is moved to the cassette 9.
3, 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° cassette kite 87 is disposed inside the side plates 2, 2 of the chassis 1 in an assembled state as shown in FIG.
, 79a as long hole 4. It can be easily assembled by simply fixing it to the side surface of the slide frame 87 with the screws 79b in a state where it is fitted into the νJ missing portion 5. The arm 54 may be attached to the head stand 30 side last.

By the way, FIG. 19(A) 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 100 and the magnetic disk drive side are connected by electric wires, and if human power and output lines are included, the connection is made 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 is shown in Figure 19 (A).
Broadly speaking, as shown in FIG. It is configured mainly around a digital processing circuit 101 such as a circuit.

This circuit 101 includes a read amplifier 102 that amplifies the signal read out from the magnetic head. light amplifier 103
．． Lead, lie;・Selector switch 104. Index amplifier 105 that generates one pulse signal when the magnetic disk rotates once. A track position detection amplifier 10fl for detecting the trunk position of the magnetic head, a motor drive circuit 107 for rotating the i5 disk, and the like are connected.

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

That is, first, when information to be recorded is input from the computer 100 as a command to the digital processing circuit 101, the circuit 101 inputs a signal to the changeover switch 104 to switch the magnetic head from the reproduction mode to the recording mode, and at the same time switches the magnetic head from the reproduction mode to the recording mode. 1'03 is set to the operating state.

Further, after instructing the speed control circuit 108 to perform a low speed rotation operation via the signal line 110, confirming that the signal interval from the amplifier 111 and the speed control interval time match, and confirming that it is in a low speed rotation state, A recording signal from the computer 100 is input to record information on the magnetic disk.

Conversely, when a playback command is issued from the computer side, the read/write changeover 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 108, 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 19 (B) shows the rotation speed of the magnetic disk at 30 Orpm.
This shows the output characteristics when the output of the magnetic head is set to Jll+ when information is read by changing the speed from 1 to 60 Orpm.

Recording frequency f = 125k)! z, when the disk rotation speed is 300 rprB, the magnetic head output is adjusted to 0.8V, and the rotation speed is doubled with this point P as the origin.
By doing so, the Q point of the magnetic head output was almost doubled.

In addition, when the recording frequency f is doubled to 250kHz, the magnetic recording density increases, so the origin is approximately 25% of the point P.
A reduced output of 5 points was obtained, and when the rotational speed was doubled in this state, an output of 8 points, which was approximately twice as much as the 5 points, was obtained.

Based on this output characteristic, if a magnetic disk is rotated at 30 Orpm and magnetic recording is performed at a frequency of 250 kHz, 8 points of Q and 6 V will be obtained when reproduced at that rotation speed, but as mentioned above, during reproduction In this case, the rotation speed is Eioo
When set to rpm, 8 points of 1.2v output were obtained.

In other words, a positive output voltage of o and ev can be obtained, and 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, the output voltage is sufficient for digital processing. was obtained, and reliability could be improved.

By the way, when recording the image signal of Prevision 112 on a magnetic disk, if the magnetic disk is set to 360 Orpm when recording one screen of a cathode ray tube, one per track.
Since the fields are synchronized, one side can be recorded.

Note that one screen is one field, and there are 1 second ÷ 60 screens = 18.7 ms.

By the way, the frequency at which television images are recorded on a magnetic disk is 6. IM)! z, the rotation speed is 3800 rpm ÷ 30 Orpm = as explained in Fig. 19 (B).
If the output is increased by 12 times, the output should increase, but the recording frequency becomes 6.1 MHz ÷ 250 kHz = 24 times, the recording degree increases, and the amplifier output becomes approximately 0.4 to 0.5 V. Recording and reproducing television images can be reliably performed by rotating the disk at high speed.

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

That is, the aforementioned printed circuit board 65 and 113°114
It is.

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

Further, the board 113 is equipped with a magnetic head read/write 9J changeover switch, read and write amplifiers, and the board 114 is equipped with interface-related circuits 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 connected to these is provided on the board 114 side!
16 was installed to allow easy connection between each board.

As shown in Figure 18, each board can be accessed from the bottom and side surfaces of the chassis, so adjustments and confirmation of electrical signals can be easily performed from outside the chassis. can be easily repaired by replacing the board.

By the way, magnetic disk drives 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 faces and sides are made of an iron slide frame 78 and a slide plate 8.
4. It is covered by a cassette guide 87 to block external magnetic fields and has a structure with a large magnetic shielding effect.

FIGS. 20(A) to 20(D) illustrate the trunk of a magnetic disk. Although the figures show eight tracks, in reality, 40 tracks can be recorded.

FIG. 20(B) shows an enlarged view of tracks [0 to 2], and the track width a is 50p, m.

l・Rack spacing is 70gm,) Rack pitch is a+
b=120 jL m.

In this way, if the track spacing 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. The state where the capacity has been increased is the 201st peel (
Shown in C).

In FIG. 20(C), a=5 (17zm.

b=lO)Lm, track pitch is a+b=BOI
It is Lm.

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

Therefore, in the present invention, as shown in FIG. 20(D), 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, when the magnetic head 47 was shifted from the outer circumference to the inner circumference at intervals of 10 pLm with respect to the magnetic disk shown in FIG. 20(D), and the reproduction output was measured, the result was as shown in FIG. 21(A).

This reproduced output voltage is obtained by measuring the output of the read amplifier 102.Finally, this reproduced output voltage is input to a digital processing circuit, shaped into a 5V peak-to-peak pulse at TTL level, and connected to a computer or the like.

Therefore, when inputting the output shown in Fig. 21 (A) to the digital processing circuit, the input level is set to 0.4V and the human power is 0.
．． If the setting is such that a voltage of 4 V or higher generates a pulse, and a voltage lower than that does not generate a pulse, the misalignment between the centers of the track and the magnetic head = fr, as shown in Figure 21 (A), even if the deviation is ±251 LI11. A regular digital signal will be generated.

Therefore, the total dimensional deviation 7t- due to vibration of the morph 11114, error in the radius of the cam 26, expansion and contraction of the magnetic disk due to temperature and humidity, etc. is allowed up to ±25 pIN.

On the other hand, the double-density I rack shown in FIG. 20(C) is
FIG. 21(B) shows the output when 1 is generated.

In FIG. 21(B), curve A represents the output characteristic of trunk [01] when no magnetic recording is performed on track [1], and song mB represents the output characteristic of trunk [01] when magnetic recording is not performed on track [0]. ] shows the 41 characteristics obtained by measuring the output.

Record information in trunk [0] and [11, and record information in trunk [0] and [11,
When measurements are taken by moving the magnetic head from track [0] to track [1], an output as shown by curve C is reproduced between curves A and H.

In other words, information interference occurs.

When measuring the voltage in the diagonally shaded area surrounded by curves A, B, and C, curves A and B are not completely summed to form line C, but other noise component power ζ is mixed in. I understand.

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

In such a case, as shown in Figure 21 (B), the limit for the amount of deviation between the i-rack and the magnetic head is about ±124 m, which is 1/2 of the 211-th strip (A), and the digital circuit This means that the input level to 0.65V must be set to 4.

That is, if an attempt is made to double the information area using the recording method shown in FIG. 20(C), the 51-normal viscosity must be doubled, which requires highly accurate and expensive parts.

Therefore, in the present invention, a recording method as shown in FIG. 20(D) mentioned above was adopted.

In other words, recording was carried out using head caps in which adjacent head caps were oriented in different directions (l/), 0l-02, alternately for each head cap.

In addition, Os = 02 = l was set to 0 degrees.

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

In Fig. 22, the ones indicated by cat numbers 117 and 118 are half-closed cores constituting one of the magnetic cores, and a gear 4. G1 is represented by the shape 1.

Further, those indicated by symbols -119 and 120 have cores forming the external force magnetic core #I, and a cap G2 having an angle of 02 is formed at the abutting portion of the two.

These cores are supported by core supports 1-121, and the core halves 117 and 119 are equipped with three coils 122.

Core support) 121 is a glass material 12 that adheres between the cores.
3. It is made of a resin that combines many glass materials with an expansion coefficient almost equal to the expansion coefficient of Sendust, which is the material of the core, and has a structure that is sufficiently resistant to environmental changes such as vibration and temperature. Ru.

I just magnetically recorded the same information on tracks [0-2].
-, the head consisting of half cores 117 and 118 in FIG. 22 is moved from the outer circumferential direction of the track to the inner circumferential direction by 10 pLI! When the reproduced output voltage was measured by moving one step at a time, an output characteristic of curve A shown in FIG. 21(C) was obtained.

In the characteristic shown by curve A, the output voltage is small at track [11] because track [1] is recorded by a magnetic head having a slope gap of 02.

That is, since the gap where track [1] was recorded and the cap of the head that is currently passing are 20 degrees apart, the output is small and the noise component increases.

On the other hand, when the head side consisting of half cores 119 and 120 is moved from the outer circumferential direction to the inner circumferential direction of the track and the 1q raw output is measured, an output as shown by the broken line B in FIG. 21(C) is obtained.

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

In this way, magnetic recording and reproduction is performed using an azimuth head having a 01-slanted gap for even-numbered digits and a 02-slanted cap for odd-numbered digits of the track containing O, thereby causing interference between magnetically recorded information between adjacent tracks. Things become extremely rare.

Therefore, if the input level is set to 0.4v, the amount of deviation between the recorded track and the magnetic head will be allowed up to 25pm.

In this way, high-density recording using magnetic heads with gap angles θ facing in opposite directions improves mechanical accuracy, and the simple mechanism facilitates design and increases the compatibility of magnetically recorded information. It turns out.

23(A) and 23(B) illustrate another example of the structure of the magnetic head. In this embodiment, the magnetic head 124 includes one set of magnetic core half-holes 125 separated by a predetermined distance.
, 126 are arranged and attached to the head stand 127.

Core half-off +25, 12fi thickness a is 50JLmte,
The spacing is 2.5 mm, and each coil is made of sendust and glass welded with a gap G = 0.1 gm.
8 is attached using the winding window 129.

When a magnetic head with such a structure is used, the magnetic head shown in FIG. 20 (B
), the core half 125 side can be responsible for recording and reproducing tracks [0 to 19], and the other core half-half 126 can be responsible for recording and reproducing tracks [20 to 39].

Therefore, when such a magnetic spatula l' 124 is used, in order to record and reproduce 40 tracks, the pulse motor 8 must move the head stand 12 in 20 steps 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 that has only - cores, if you want to change it to tracks [0 to 20], calculate the range between 114+ and the speed characteristic of a pulse motor is 3ms for one track, so 20X3ms=eOms. .

In addition, even if the magnetic vent reaches the position of No. 20 [1], the pulse motor 8 does not suddenly reach 1 and vibrates slightly, so wait until it stops before recording or playing back. There is a need. So almost? Recording and playback cannot be started until after Oms.

On the other hand, if the head shown in Fig. 23 is adopted, after recording and playing back track [0], the trunk [2
0] can be recorded and played back.

Furthermore, a head with one core requires 3ms x 39+ 10 (waiting time) = I27ms for recording and playback of tracks 0 to 391, whereas the head shown in Figure 23 requires 3ms x 19+ 10 (waiting time) = 6? +ns, a difference of 60 m5 occurred, and it was found that higher speed could be achieved.

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 lower cassette halves 130 and 131, between which a magnetic disk 94 having a center hub 95 is accommodated. Each cassette half has a through hole 132 into which the center hub 95 is fitted.
, and a head window 133 is formed respectively.

Also, what is indicated by the numeral 134 is an arrow indicating the cassette installation method, and what is indicated by the numeral 135 is four parts on which a label 136 for writing the program name, etc. is pasted.

Reference numerals 137 and 138 indicate positioning holes into which the projections 7a at the upper ends of the pins 7 are fitted.

By the way, the shutter 13B is fitted to the outside of the cassette halves 130 and 131 which are aligned vertically, and has a U-shaped cross section, and is slidably fitted between the cassette halves 130 and 131 from the outside of the cassette. Ru.

At one end of the shutter 139, there are three projecting pieces 141 that are slidably fitted into grooves 140 formed on the surface of the cassette half 130.

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 I halves, and guides the shutter 139.

Further, a pin 145 is protruded from the innermost end of the groove 144 of the F-side cassette half 131, and a spring 146 is stretched between the pin 145 and the bent portion 142, Shack 13 towards the center of the half
It gives you the power to attract 8.

In addition, the grooves 143 of the cassette (half 130, 131,
A lower step 14 for guiding the bent portion 142 along the side edge of the 144? are formed respectively.

On the outer surface of each cassette half 130, 131, a quadrilateral four part 14B is formed, which is in contact with a shutter 139.

Further, the reference numeral 149 indicates a shutter stop.

Further, when the cassette I is inserted into the cassette kite 87, the one indicated by the reference numeral 150 passes through a bent portion 87d for opening the shutter protruding from the 1'' end of the cassette guide 87 when inserting the cassette I. It's a groove.

As shown in FIG. 28, this bent portion 87d contacts the edge 139a of the shutter 13'9 on the cassette mounting surface, and when the shutter 13' is in the closed state, the bent portion 87d
Open 38.

FIG. 26(A) shows a state in which the shutter is closed.

(B), and the opened state is shown in FIG. 26 (C).

CD).

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

[Effect] As is clear from the explanation below, according to the present invention, a structure in which a plurality of magnetic heads are provided separated by a predetermined interval is adopted, so that the step time of the magnetic head is shortened, and the magnetic recording speed is improved. This has the excellent effect of allowing playback to be performed at high speed.

[Brief explanation of the drawing]

Figure 1 is an exploded perspective view of the disk and head drive mechanism, Figure 2 is a perspective view of the chassis with the head drive mechanism installed, and Figure 3 illustrates an embodiment of the present invention.
The figure is A-Afi sectional view in Figure 2, and Figure 4 is B-A in Figure 2.
5(A) is a sectional view showing one bearing structure of the head stand; FIG. 5(B) is a sectional view showing another example of the bearing structure; FIG. 5(C) is a sectional view showing the other bearing structure of the head stand, FIG. 5(D) is a sectional view taken along the line CC in FIG. 5(C), and FIGS. 6 and 7 are the cam structure and the outermost track position. Explanatory drawings showing the structure and operation of the detection mechanism, Figures fJ and B are exploded perspective views of the cassette loading mechanism, Figure 9 is a perspective view of the assembled cassette loading mechanism, and Figure 10 is the cassette loading immediately after inserting the cassette. A cross-sectional view of the mechanism, FIG. 11 is a cross-sectional view of the cassette loading mechanism in a fully loaded state, FIG.
Figures (A) to (G) are explanatory diagrams showing the operation of the rollers during the cassette loading operation, Figure 13 is a cross-sectional view of the cassette loading mechanism after the cassette has been lowered, and Figure 14 is a cross-sectional view of the cassette loading mechanism after the cassette has been lowered. 15 is a perspective view showing the relationship between the cassette loading mechanism and the chassis, and FIG.
The figure is a perspective view of the chassis with the cassette mounting λ7 mechanism visible, Figure 17 is an explanatory diagram showing the arrangement of the board on which the control circuit is mounted, and Figure 18 is a side view of the chassis with the board visible. FIG. 19(A) is a block diagram of the control circuit;
Figure (B) is a diagram showing the relationship between the rotation speed of the media and the playback output, Figure 20 (A) is an explanatory diagram of tracks on a magnetic disk, and Figure 20 (B) is an explanatory diagram of roughly recorded tracks. ,
Figure 20 (C) is an explanatory diagram of densely recorded tracks;
FIG. 0 (D) is an explanatory diagram of the recording method adopted by the present invention, and FIGS. 21 (A) to (C) correspond to the recording states shown in FIGS. 20 (B) to (D), respectively. Figure 22 (A) is a diagram showing the force characteristics of the cow, and Figure 22 (A) is a plan view of the magnetic head.
B) is a sectional view taken along the line D-D in FIG. 22 (A), and FIG.
) is a plan view showing another example of the structure of the magnetic head, and FIG. 23 (
B) is a sectional view taken along the line E-E in Fig. 23 (A), and Fig. 24 (A
), (B) 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. 26 (A) and (, B) are views with the shutter closed. Top and side views of the cassette, Figure 26 (
C). (D) is a plan view and side view of the shack in an open state;
Figure 27 is an enlarged sectional view taken along line F-F of Figure 26 (A),
FIG. 8 is a perspective view illustrating the opening operation of the shack. 93...Magnetic disk cassette 94...Magnetic disk 124...Magnetic head 12
5... Core half rest 128... Coil Fig. 11 Fig. 1.3 Fig. 8] ICI 13b6-IQ61 Fig. 12 Fig. 1-4 Rebellion methine 7 times □ Fig. 19 (A) Fig. 20 Figure (A) Figure 20 (B) Figure 21 (A)! 31 beard ijiku! I- Figure 21 (B) He--1 day, 1+vl1111--1-mark 2/7 nori ≧ trivial 9! ΣP Ya 1 Wa) 1-1 Fig. 21-(C) Upper'L Fig. 22(A) Fig. 22(B) Shi-'Lj 11'8 Fig. 23(A) 126 126 Fig. 233(B) ) Figure 26 (A) Figure 26 (B) It*l 139 Figure 26 (C) Figure 26 (D) +41 IJ9

Claims (1)

[Claims] A magnetic disk device characterized in that a plurality of rM1 heads for performing magnetic recording and reproduction on a magnetic disk are provided at predetermined intervals.