JPS60109069A - Magnetic disk device - Google Patents

Abstract

PURPOSE:To prevent the position shift between a track and a magnetic head by using materials which are nearly the same in coefficient of linear heat expansion for expansion for constituting a magnetic disk and a cam for moving the magnetic head. CONSTITUTION:The deviation between the track position on the magnetic disk 64 which rotates while loaded on a coupler on a rotating shaft 20 and the position of the magnetic head 47 is prevented. For the purpose, the head base 30 on which the magnetic head 47 is fitted is moved through a cam 26 and a gear 44; and the magnetic disk is made of synthetic resin nearly entirely except a center hub and the driving mechanism side of the magnetic disk, on the other hand, is nearly made of metal, so the influence of heat expansion is exerted. The cam 26, therefore, is constituted of synthetic resin having nearly the same coefficient of linear heat expansion as the magnetic disk 64 to prevent the influence of temperature variation to be exerted on distances L1 and l1 from the center of the rotating shaft 20.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic disk device, and more particularly to a magnetic disk device having an improved 1F structure for preventing misalignment between a track position and a magnetic head.

[Prior Art] If the linear expansion coefficients of the magnetic disk and the cam that moves 7t' to the magnetic field are different, the track position and the magnetic head position will deviate due to temperature, resulting in tlT raw output output).

When the reproduction output decreases, accurate information cannot be reproduced, and incorrect information is read out, resulting in lower reliability.

[Objective] The present invention has been made in order to eliminate the conventional drawbacks as described in 1- below.] - To provide a magnetic disk device configured so that misalignment between the rank and the magnetic head does not occur. The target is 1.

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

The magnetic disk device according to the present invention is assembled using a chassis 1 as the basis. The chassis 1 is configured as a U-shaped frame having left and right side plates 2, 2.
2, guide grooves 3, 3 are formed from the "-" side edge toward the center. These guys] Groove 3, 3
Inside is a cassette kite, which will be described later.

In addition, a guide hole 4 is formed in a horizontal state between the kite grooves 3.3 at opposite positions of the side plate 2.2, and a guide hole 4 is formed in a horizontal manner on the front side edge of the side plates 2, 2. Carcinoma; a kite groove 5 is formed. These blade holes4. A kite roller of a slide frame, which will be described later, is fitted into the kite IIvi5.

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

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

A pulse motor 8, which serves as a drive source for moving the magnetic hand, is fixed to one end of the bottom plate 6 of the chassis via stands 8a, 8a, and a protruding piece 9 cut and raised from the bottom plate 6 is protruded near it. has been done. A through hole 10 is formed in the projecting piece 9, and a through hole 11 is formed in one side plate 2 in a state opposite to this through hole 10. A guide shaft 1 on which a head mount, which will be described later, is guided using these through holes io and ii.
2 is suspended horizontally.

Further, on the front side of the chassis l, another guide bar 13 is horizontally suspended between the side plates 2.2 in parallel with the guide shaft 12.

On the other hand, a drive gear 14 is fixed to the output shaft of the pulse motor 8 on the lower side.
meshes with a gear 15 rotatably supported on the bottom plate 6 at 4111.

A through hole 16 is formed in the middle part of the bottom plate 6, and a housing 17 that supports a rotational drive mechanism for a magnetic disk can be inserted into the through hole 16.

As shown in FIG.
- overlapping them and fitting the lower part of the boss 17 into the through hole 16;
It is fixed by screws 18 via the flange 17a.

Inside this boss 17 is one set of bearings 19.19
Rotation +l+20 is rotatably supported via the shaft. A collar 21 is arranged between the - and F bearings 19. The outer ring of each bearing 19.19 is press-fitted into the boss 17.

A coupler 22 is fixed to one end of the rotation +l:l 2 o. The coupler 22 is fitted to the center hub of the magnetic disk drive center, and a positioning pin 23 is fitted into the flange 22a with a force A and an outlet A.

The do end of the pin 23 is fixed to the F side of the flange 22a and the free end side of the plate 24, and the X bow 91111
It is given a protruding force + knee + movement habit.

A spring 25 force; 9M is installed between the 1ζ surface of this coupler 22 and the inner ring of the bear I nongator 19 on the second side.
By pressing the inner ring downward, a relative positional shift is created between the inner ring and the outer ring, uniform contact is created between the inner and outer rings and the hole, eliminating the looseness of the inner and outer rings, and rotation ll:b
20 l/) is made so that no runout occurs.

A gear 27 is fitted and fixed to the boss 17 via a boss 28 with the cam 26 on the other side.
7 to the destination side. A tightening washer 29 is fitted on the outside of the boss 28, and a lock is provided to prevent the cam 26 and the like from being removed.

On the other hand, the one indicated by the numeral 30 has a size of 212 and is formed into an elongated plate shape. One end of the head stand 30 is slidably fitted to the guide shaft 12 via a linear bearing 31.

The other end of the hand stand 30 is slidably guided by a single guide shaft 13.

That is, on the free end side of the hend stand 30, as shown in FIG.
A shaft 33 for rotatably supporting a circular roller 32 is protruded downward as shown in FIG. A spring 34 is loaded between the foot 33 and the roller 32, and the roller 32 is given a tendency to move towards the tip.

In addition, 1llll 33 is attached to the base 3 by the screw 35.
One end of a leaf spring 36 is fixed to the 1- side of the hend stand 30 by this screw 35, which is fixed to the 0 side.

Bend table 30 whose side is covered by this leaf spring 36
A roller 37 is rotatably fitted in the opening 30a formed in the opening 30a in a state perpendicular to the guide yoke 113.

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

In this way, the bearings 12 and 13 that guide the movement of the head stand 30 are linear bearings and bearings that utilize the rotational friction of rollers, which have extremely low friction because they are interposed between members, and are far more effective than bearings that utilize sliding friction. The head stand can be moved smoothly.

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

However, as shown in No. 51K(B), the guide shaft 12 is guided by the member 38 that uses sliding friction, and the material of the bearing 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 3 is installed between the head stand 3o and the protrusion J19.
9 is stretched, giving the head stand 30 the habit of moving toward the rotating shaft 20 side.

This head stand 30 is marked on the - side of the cam 26, and one end of a lever 40 is attached to a screw 4 on the back side of the head 30.
It is rotatably supported by 1.

A spring 42 is stretched between the other end of the lever 40 and the head stand 30, giving the lever 41 the ability to rotate in the direction opposite to the clock in FIG.

A roller 44 is rotatably supported on the lower surface of this /<-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 force 1.26 has a spiral shape as a whole and has a large number of serrated cam surfaces. In some cases, there are 40 corresponding cam parts.

In Fig. 6, each cam part is set so that the radius indicated by symbol RO is the maximum half-frame 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 is used to rotate this cam once.
The rotation is transmitted through gears 14, 15, and 27.

In reality, when one driving pulse is applied to the pulse motor 8, the pulse motor 8 is set to rotate 18 degrees, 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 27 changes to 6.
The gear ratio of each gear 14, 15.27 is set so that it rotates 6 degrees, and within this 6° range, the radius is R, 0 to R.
Forty 39 cam portions are formed.

Therefore, every time the cam rotates 66 times, the magnetic field becomes 71.
・It will now move by the rack, and the specific amount of movement will be 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 adjustment lever 45 is screwed into a bent portion 30a that 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 side edge of the free end of the lever 40, as shown in FIGS. I
You can save.

Further, a rectangular opening 30b is formed midway in the longitudinal direction of the vent stand 30, and a magnetic head 47 is disposed S therein via a support member 46.

An arcuate plate spring 49 is elastically mounted between one end of the support member 46 and a protrusion 48 protruding from one end of the open Ij portion 30b. The tip of the adjustment screw 51 screwed into the protrusion 50 is in contact with the side edge of the support member 46 on the side opposite to 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 be adjusted.

This key 1! i) The screw 51 allows the center of the magnetic head to be precisely adjusted 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.

By the way, brackets 53, 53 are protruded from the end of the head stand 30 on the guide shaft 12 side.
It is rotatably supported via the shaft.

A torsion coil spring 56 is wound around the pin 55.
The putt arm 54 is given the habit of rotating clockwise in FIG. 4.

The tip of the pad arm 54 extends to three sides of the magnetic head 47, and an adjustment screw 57 is screwed to the tip in correspondence with the magnetic head 47, and a pad for pressing the magnetic disk is provided at the bottom end of the pad arm 54. A terminal 58 is provided.

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 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 59a.

A pin 6 is provided on the bottom plate 6 on the side of the control plate 59.
0 and <-51 are rotatably mounted. At one end of this lever 61, protrusions 61a and 61b are formed separated by a predetermined distance, and these protrusions 61a,
61b is always in contact with the outer peripheral surface of the control plate 59.

The other end of the lever 61 is elongated and faces toward a position that closes the L side of the notch 6a formed at the front edge of the bottom plate 6. Then, facing the notch 6a,
A sensor 62 is arranged. The 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.

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

Therefore, as shown in FIG. 6, when the roller 44 is at the cam portion with the radius RI, the protrusion 61b of <-61 is the protrusion 59.
a, and one end of the lever 61 is in a state where the L side of the sensor 62 is closed.

In this state, the projections 61a and 6 are in contact with the peripheral surface of the control plate 59, and the shield 61 does not rotate.

When the cam 26 is rotated an extra 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. It will correspond to the location.

At this time, as shown in FIG.
The protrusion 61b contacts the protrusion 61b, and the protrusion 61b is rotated in the opposite direction 81 in the figure, and the protrusion 61b is fitted into the notch 59b.

At this time, one end of the lever 61 is moved N from above 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, the outermost trunk is set to 0 track, and this position is reliably detected by the above-mentioned mechanism.
If you set the magnetic head so that it always reaches this position when the power is turned on, the head position when scooting will match the 0 track, and if you apply a pulse to the pulse smoke 8 from this position, the 5 When the head moves to the 5th track for pulses and to the 10th track for 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 specifications between the control board 59 and the lever 61 are H.
Physically, it is as follows.

That is, as shown in the 6th jΔ, the radius R of the control plate 59 is 15
++on, when the rotation angle α of l step is 6°, the moving distance of the peripheral edge of the control plate 59 δ=tan6°X]5mm=1.
It is 6n+m.

Also, the distance #l from the pin 6o of the lever 61 to the tip;
B = 5m + n, distance from pin 6o to rear end # -
13 mm, the moving distance of the rear end of the lever 61 is 612, and the rotation angle is α', α' = 1515 XEi O = 180, δH: ta
n 18° x 13 + nm 44.2 mm.

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

As a result, the outer end of the lever 61 is rotated by 4.2+nn+, and if the size of the sensor 62 is 3 mm, the sensor surface can be sufficiently opened and closed.

Of course, if the sensitivity of the sensor 62 itself is increased, the protrusion 59a
My own 1. Movements on the order of Eimm can be detected sufficiently.”
- By using the lever as described above, movement of the control board can be detected easily and inexpensively.

By using such a sensor, 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 not subject to space restrictions can be obtained.

By the way, a magnetic disc hub is attached to the coupler 22 provided at one 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. 24(A), the distance from the center of the rotating shaft 20 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 rotating shaft 2 is 11.
The distance between the centers of 0 is 1+22. If the distance from the periphery of the center hub 63 to l rank is 13, then the part 2 is metal and the part 13 is synthetic resin, specifically l 1
= 20mm.

When −f22=8 mm, 13 becomes 12+nm.

On the other hand, on the drive side, the distance from the center of the rotating shaft 20 to the track is expressed as: the distance NIL2 from the center of the rotating shaft 20 to the periphery of the boss 28, and the distance L- from the boss 28 to the periphery of the cam 26. 3. From the periphery of the cam 26]・
This is the total distance L4 to the rack, and each part is made of metal.

Therefore, T-2 = 8mm, L/I = 1.5m
If m, then L1 = 20 + nm, so L3 = 20-
8 1.5 = 10.5++ on.

Now, if the error between Ll and 121 is set to zero at a temperature of 25°C, and the temperature becomes 20°Cj:, JL and becomes 45°C, the following result will be obtained.

In other words, the coefficient of linear expansion of metal is 16×lo″6ml1
/°c, the linear expansion coefficient of the synthetic resin filter is 17X ]O
= mm/ °C and 6 and -11, L+ is II l(1
+ ci:t) −δNear+subtracting gives the following.

−(l s =, (12+, (23=(8+8'X20
XleXIO=)+ (+2+l2X20X]7XIO
”) = 20.043 mm Ll=L1 +L2+L:3 = (8+ 8 x 20X IflX 10″3)+
(1,5+1.5 X20X16XIO condolence)+(10
,5+I0.5X 20X ]6X 10i3)='2
0.008++on That is, when the temperature is 20'CJ2y1, the difference between Ll and 11 is 20.043-20.0OB=3 full m, and the information on the magnetic disk cannot be read accurately at IF.

Therefore, in the present invention, the material of the cam 26 is
If it is made of a synthetic resin having a coefficient of linear expansion that is approximately the same as 4, Ll will be as follows.

L, = (8+ 8 X20X 113X 10i5)+ (1,5+ 1.5X 20X 16X 10
” ) ten (10,5+ IO,5X 20X 17X
10") = 20.038mm In other words, by changing the material of the cam, Ll and j2 +
The difference is 20.043-20.038 = 5pm.

Therefore, the influence of thermal 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, Ll can be accurately set to 20 mm without looking at the position of the magnetic head 47 using a microscope or the like.

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

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

Therefore, when the cam 26 rotates, the gaps δ1 and δ2 between the bosses 17 and 28 constantly change, and this change directly affects Ll.

In order to eliminate this influence, in the present invention, a spring 39 is stretched between the head stand 30 and the protruding piece to keep the gap δl between the bosses 17 and 28 on the magnetic head side 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 l, and a member constituting the motor can be removed between it and a printed circuit board 65 fixed to the lower side of the chassis l.

That is, the coil 65a or the solder pad is fixed to the lower surface of the printed circuit board I.

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 7o is fixed to two sides of the yoke 68 in a shape E facing the first 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 an index signal.

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 No. 31;4.

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. 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 is used as a signal. It can be taken out.

A motor for rotating the magnetic disk is constituted by the two connected coils 65a and the permanent magnet 7o side.

By the way, this motor is set to rotate at 20 On+s per revolution.

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

That is, since the diameter of the gear 69 is 5 Drnrn, the module is 0.25, and the number of teeth is 200,
200m5 ÷ 200 = 73 sensors at an interval of Ims
The rotation changes are monitored.

The printed circuit board 65 is a thin insulating board and is fixed to the iron chassis l, 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 to the permanent magnetic coil 70 and hence the yoke 68. Gear 69 is rotated.

By fixing the printed circuit board 65 to the iron chassis 1 in this way, it is possible to narrow the distance between the permanent magnet and the chassis, and the effectiveness of the magnetic circuit is increased by -14.
do.

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 l side, the inner ring of the bearing 19 on the first side is pressed in one direction by the boss 66, so that it absorbs the play of the bearing 19. Together with the side bearings 19, vibration of the rotating shaft 20 can be prevented.

On the other hand, the inner and outer diameters of the boss 17 fixed to the chassis 1 are simultaneously machined based on the fixed part to the chassis 1 [
Since it is a ship, the inner and outer diameters can be pressurized by one ship with an inner and outer diameter of 1 to 2 μm.

By this machining accuracy and absorption of the backlash of the bearing 19, the runout of the rotating rack 120 including the boss 17 can be maintained within 5μ7m.

This concludes the explanation of the drive mechanism section, and then the skein, 1.
The mounting mechanism will be explained.

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

That is, what is shown by row pair 78 in the figure is a slide frame formed as a frame body with a lower blade and an open front and back.

Rollers 79 are rotatably supported on both sides of the slide frame 78, and these rollers 79 can slide freely into the slotted holes 4 formed in the side plates 2, 2 of the chassis 1, 11f1. They are rotatably fitted.

There are openings at the corners of the left and right ends of this slide frame 78.
A portion 78a is formed, passes above the opening 78a, and protrudes integrally from the -L surface of the slide frame 78) 178
b is provided protrudingly. A spring 80 is stretched between the protrusion 78'b and a protrusion 2a protruding from the side wall of the chassis 1.

Therefore, the slide I/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 the protrusion protruding from the lower end of both side plates of the slide frame 78. the chassis I through this roller 81.
L can be slidably moved.

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 are formed in two parallel places.

A slide I/plate 84 is slidably arranged on the left and right inner surfaces of the slide frame 78. The slide plate 84 is formed in a rectangular shape, and the end thereof is connected to the bottom plate 6 of the chassis 1. 1- of the small diameter shaft portion 81 of the roller 81 in contact with
It is in contact with a.

A protrusion 84a is provided on one of the two wheels of this slide plate 84, and this protrusion 84 is provided with
It fits into the first part 78a and plays the role of a kite 1-1.

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

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

A projecting piece 84c is provided on the inside of the tip of the slide I/plate 84, and a spring 8b is stretched between this projecting piece 84c and the slide frame 78.

Incidentally, a cassette kite 87 is arranged on the t' side of the slide frame 78.

The cassette guide 87 is formed as a frame with an offset)+L, and on the left and right sides thereof, there are rail portions 8 that serve as guides for the cassette.
7a is formed.

Further, a cassette kite 88 is provided protrudingly, and pins 89 are provided protrudingly from each projecting piece 88, and a roller 90 is rotatably supported at 4111 on these pins 89.

Each roller 90 includes the slide plate 84 and the slide frame 78.
18I to the opening! 85, is rotatably fitted into the elongated hole 83.

In addition, an opening 11 is provided in the center of the upper surface of the cassette kite 87.
A frame 91 is provided in a state that extends over the 1'' portion 87b, and a knob holder 92 is removed from the frame 91. ing.

Furthermore, an opening 1 portion 87c into which the magnetic head is inserted is formed on the side of the opening 87b.

The slide frame 78 described above. A cassette mounting mechanism is composed of three members: a slide plate 84 and a 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 eighth position by the tensile force of the spring 80.
It has moved to the right in Figures 1 and 13.

In this type of fishing 1, the roller 90 is located in the kite groove 3 and at the upper end of the elongated hole 83 as shown in FIG. It is located on the section 85a.

That is, 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.

Further, the slide plate 84 is also moved by the spring 86 to the first position.
The cassette guide 87 is pulled to the right in Figure 3.
is regulated by the stepped portion 85a, and is positioned on one side of -1 to receive the cassette.

In this situation, when the cassette 93 is fitted into the rail portion 87a of the cassette I 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 plate 84 is moved forward against the tensile force of the spring 86.

Then, as the plate 84 moves, the opening 11 part 85
As shown in FIGS. 12(A) and 12(C), the roller 90, which was located in the kite groove 3 and at the step 85a of the 11th part 85, moves to the reassembled part of the opening 85. It will fall to the side and be guided below the vertical part of the guide groove 3 and the opening 85, as shown in FIGS. 12(B) and 12(D).

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

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

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 positioning pin 7 is lowered, the protrusion 7a of the pin with the protrusion 7a is fitted into the positioning hole 93a of the cassette 93, and the end of the pin 7 without the protrusion 7a contacts the bottom surface of the cassette to support the cassette. Perform positioning. This state is shown in diagram Sl1.

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, 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 loaded 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 up, returning to its original position.

When the cassette kite 87 and the roller 90 are placed above the opening 1-1 section 85, the slide plate 8
4- is moved to the right as shown in FIG. 13 by the tensile force of the spring 86, and the roller 90 is moved to the horizontal portion of the opening 85 and rides on the stepped portion 85a''-. Due to this movement of the slide plate 84, the bending portion 84b pushes the cassette 93, so that the cassette 93 is pushed forward from the end of the cassette kite 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 l 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 while it is fitted into the notch 5. The putt arm 54 may be placed on 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 the input and output lines are connected by approximately 34 electric wires.

All of these 34 input/output lines are processed using 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 the figure, there are pulse motors for coupling with the computer 100, for amplifying and digitizing the outputs of the magnetic disk drive and various sensors, and for positioning the magnetic head on a predetermined track. It is mainly configured with a digital processing circuit 101 such as a drive circuit.

This circuit 101 includes a read amplifier 102 which amplifies the signal read out from the magnetic head. light amplifier 103
．． Read/write switch 104. Index amplifier 105 that generates one pulse signal when the magnetic disk rotates once. Track position detection amplifier 106 for detecting the trunk position of the vehicle head. A morph drive circuit 107 and the like for rotating the magnetic disk are connected.

Also, the one indicated by the symbol % +08 is a speed control circuit for controlling the rotation speed of the motor, and the motor drive circuit 107 is a speed control circuit for controlling the rotation speed of the motor.
The signal lines 108 and 110 from the digital processing circuit +01 perform speed control as described later.

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 circuit configuration as described above, in addition to the general disc rotation speed during recording and playback at the same speed, high-density recording can be performed and reliability can be improved. 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 the write amplifier 103 is in the operating state.

Also, after instructing the speed control circuit 10B to perform low-speed rotation operation via the signal line 110, confirm that the signal/interval from the amplifier 111 matches the speed control interval time, and confirm that it is in the low-speed rotation state. , inputs a recording signal from the computer 100 and records information on the magnetic disk.

Conversely, when a playback command is issued from the computer side, the read/write selector 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 the combination 5-100 is manually operated.

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.
The output characteristics are shown when the output of the magnetic head is measured when changing the speed from 1 to 80 orpm and outputting information one after another.

Recording frequency f = 125kHz, disk rotation speed 3
Adjust the output of the 11+j magnetic head set to 0Orpm to 0.8V, and use this point P as the origin to double the rotation speed BOOrpI.
When it was set to ll, the magnetic head output was almost twice as high as the Q point.

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 at 8 points was obtained, and when the rotational speed was doubled in this state, the R point, which was about twice the output compared to 3 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, three points of 0.6 V will be obtained when reproduced at that rotation speed, or as mentioned above, during reproduction In this case, the rotation speed is 60Or
When set to pm, an output of 1.2V at point R was obtained.

In other words, a positive output voltage of 0.6V can be obtained, which is sufficient for digital processing 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. Voltage was obtained and the reliability was improved.

By the way, when recording Prevision+12 image signals on a magnetic disk, when recording one side of a cathode ray tube, if the magnetic disk is set to 3 [iloorp], one field is synchronized with one track, so one screen can be recorded. .

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

Since the frequency at which TV images are recorded on the magnetic disk is 6.1 MHz, the rotational speed is 3600 rpm -4-30Orpm= as explained in Fig. 19 (B).
If it is multiplied by 12, the output should increase, but the recording frequency becomes fl, IMHz ÷ 250kHz = 24 times,
Since the recording density increases and the amplifier output becomes approximately 0.4 to 0.5 V, recording and reproducing television images on the magnetic disk 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 track position detection circuit, a morph drive circuit, and the like.

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

Kaoru, connecter 115 to each of boards 65 and 113.
are provided, and a connector 116 coupled to these is provided on the board 114 side to allow easy connection between each board.

As shown in FIG. 18, each board is connected to the -1-
Since it is attached to the front and side faces, it is easy to adjust and check electrical signals from outside the chassis, and if any circuit breaks down, it can be easily repaired by replacing the board.

By the way, magnetic disk devices are used as storage devices in computers, but in this case there is a brown disk around the device. Since there are parts such as 6, power transformer, and motor that generate strong magnetic fields, it is necessary to protect the equipment from these magnetic fields.

Therefore, in the present invention, the chassis l is formed into a U-shape, and its -1 side and side surfaces are made of an iron slide frame 78, a slide plate 84. 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 tracks of a magnetic disk, and although the figures show eight tracks, in reality, 40 tracks can be recorded.

FIG. 20(B) shows an enlarged view of the track [O-2], and the I/rack width a is 507 Lm.

Track spacing is 70p, rn, track pitch is a+
b=120 km.

In this way, when the inter-track Hb is larger than the trunk width, if it is possible to record between l/racks, 40 tracks can be increased to 80, and the recording capacity can be doubled.
do.

FIG. 20(C) shows a state in which the volume h1- is doubled.

In FIG. 20(C), a=50 pLm.

b=10gm, track pitch is a+b=I30gm
It becomes.

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

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 pLI11 with respect to the magnetic disk shown in FIG. 20(D), the reproduction output was measured, and 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 manually inputting the output shown in Figure 21 (A) to the digital processing circuit, set the input level to 0.4V so that the input 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 amount of deviation between the center of the track and the magnetic head will be ±2 as shown in Figure 21 (A).
Even if there is a deviation of 5 pLm, an IY-standard digital signal is generated.

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

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

In FIG. 21(B), curve A represents the output characteristic of trunk [0] when magnetic recording is not performed on track [1], and song ff1B represents the output characteristic of trunk [1] when magnetic recording is not performed on track [0]. The characteristics of the measured output are shown.

Record information on tracks [0] and [11, and record information on tracks [0] and [11.
When measuring by moving the magnetic head from the track [1] direction to the track [1] direction, an output as shown by curve C is reproduced between curves A and H.

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 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. 21(B), the deviation between the track and the magnetic head will be 1/1 of that in FIG. 21(A).
The limit is approximately ±12gm of 2, which means that the human power level for the digital circuit must be set at 0.65V.

That is, if an attempt is made to double the amount of information using the recording method shown in FIG. 20(C), the dimensional accuracy must be doubled or more, and high-precision and expensive parts are required.

Therefore, for unreleased 1, a recording method as shown in FIG. 201 (D) described above was adopted.

In other words, the head cap has 0I for each adjacent track.
= 02, and recording was performed using those facing alternately in different directions.

Note that 01=02-10 degrees.

The structure of this creeping magnetic ↑rad is shown in Figure 22.

In FIG. 22, reference numerals 117 and 118 indicate half cores constituting one magnetic helad core, and a gap G1 having an angle of 01 is formed at the abutting portion of both cores.

Further, those denoted by numerals 119 and 120 are half cores constituting the other magnetic core, and a cap G2 having an angle of 02 is formed at the abutting portion of the two cores.

These cores are supported by core supports 1-121, and coils 122 are wound around the core halves 117 and 119.

The core support 121 is a glass material 123 that adheres between the cores.
Alternatively, it is made of resin containing a large amount of glass material having an expansion coefficient almost equal to that 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.

now,!・The same information was magnetically recorded on rack [O~2].
Then, when the head consisting of half-core cores 117 and 118 in FIG. 22 is moved from the outer circumferential direction of the track to the inner circumferential direction in steps of 10 pLm and the reproduction output voltage is measured, the output characteristic of curve A shown in FIG. 21 (C) is obtained. It was done.

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 02.

That is, since the gap between the cap that recorded track [1] and the head that is currently passing through is 20 degrees, 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 reproduction output is measured, an output as shown by the broken line B in FIG. 21(C) is obtained.

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

In this way, magnetic recording and reproduction is performed using an azimuth head with a 0I tilted gap for the even numbered digits of the track containing 0, a θ2 tilted gear for the odd numbered digits, and a knob, thereby allowing the magnetic recording information between adjacent tracks to be recorded and reproduced. interference is extremely reduced.

Therefore, if the input level is set to 0.4V, a deviation of 71.degree. between the recorded track and the magnetic field will be allowed up to 25JLm.

In this way, high-density recording using magnetic heads with gap angles θ facing in opposite directions makes it easier to achieve mechanical dimensional precision 1i, and the simple mechanism facilitates design and increases the compatibility of magnetic recording media. It turns out.

FIGS. 23(A) and 23(B) illustrate another example of the structure of the magnetic head. In this embodiment, one pair of magnetic cores are separated by a predetermined interval as magnetic cores l'+24, +2
5 and 12 [1], and shoot on the head stand 127.

Cores 125, 126 (7) Thickness a is 50gm, interval is 2.5mm, each is made of sendust, caps G=O, Ip, m are welded together, and coil 128 is connected to '/i 3-wire window 129. Take advantage of it and shoot.

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

Therefore, when such a magnetic head 124 is used, in order to record and reproduce 40 tracks, the head stand 12 can 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 - cores, I.
When calculating the time required to change from rack [0 to 20], the speed characteristic of the pulse motor is 3 ms for one track, so it becomes 20×3 msJOms.

Furthermore, even when the magnetic head reaches the 20th track, the pulse motor 8 does not suddenly stop and vibrates slightly, so it is necessary to wait until it stops before recording or reproducing. So almost? Recording and playback cannot be started until after Oms.

On the other hand, if the head shown in FIG. 23 is adopted, track [2] is immediately recorded and played back without any waiting time after recording and playing back track [0].
0] can be recorded and played back.

Furthermore, with a head with one core, it takes 3 ms x 39 + 10 (wait time) = 127 ms to record and play back tracks [0 to 39], whereas in the case of the head shown in Fig. 23, it takes 3 ms x 19+10 (waiting time)=
Since the time is 137 ms, there is a difference of 60 m5, and it was found that higher speed can be realized.

Next, the magnetic disk cassera 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, and a magnetic disk 94 having a center hub 95 is accommodated between the two halves. Each cassette half has a through hole 13 into which the center hub 95 is fitted.
2, and a head window +33 is formed respectively.

Further, the reference numeral 134 indicates the cassette mounting force method with an arrow, and the reference numeral 135 indicates four parts on which a label 136 for writing a 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 139 is fitted to the outside of the cassette halves 130 and 131 which are aligned vertically, and has a U-shaped cross section, and can be slid freely between the cassette halves 130 and 131 from outside. be done.

A projecting piece 141 is formed at one end of the shutter 138 and is slidably fitted into a groove 140 formed on two sides of the cassette/\-) 130 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 cassettes, and guides the shutter 139.

Further, a pin 145 is protruded from the innermost end of the groove 144 of the lower cassette 131, and a spring 146 is stretched between the pin 145 and the bent portion 142. This provides a force to draw the shutter 138 toward the center of the cassette.

Note that the grooves 143 and 1 of the cassette halves 130 and 131
44 are formed with lower step portions 147 for guiding the bent portions 142, respectively.

Each cassette half 130, 131 has four quadrilateral portions 148 formed on its outer surface to which the shutter 138 contacts.

Also, what is indicated by 149 is the end of Shan Yu's removal.

The part indicated by the symbol +50 is a bent portion 8 for opening the shutter protruding from the entrance end of the cassette guide 87 when the cassette is inserted into the cassette guide 8.
7d is a groove through which it passes.

As shown in FIG. 28, this bent portion 87d comes into contact with the edge 139a of the shutter 139 when the cassette is installed, and the shank 139 is in contact with the edge 139a of the shutter 139 when the head window 133 is closed.
open.

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

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

Shown in (D).

Since the magnetic disk cassette used in the magnetic disk device of the present invention is configured as described above, it can be kept closed at all times by simply inserting it into the cassette guide on the device side! The shutter in C1 is automatically opened, and magnetic recording and reproduction can be performed reliably.

[Effect] As is clear from the above explanation (=, according to the present invention, the material constituting the magnetic disk and the material constituting the cam for moving the magnetic head are made of materials that have approximately the same coefficient of linear expansion. Since this structure is adopted, there is an excellent effect that positional deviation between the track and the magnetic head does not occur due to temperature changes.

[Brief explanation of the drawing]

The drawings are for explaining one embodiment of the present invention. Fig. 1 is an exploded perspective view of a disk and head drive mechanism, and Fig. 2 is a head drive 1! Perspective view of the chassis with the structure installed, 3rd
The figure is a sectional view taken along line A-A in Figure 2, and Figure 4 is a sectional view taken along line B-B 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, and FIG. 5(C) is a sectional view of the head stand. 5(D) is a sectional view taken along the line CC in FIG. 5(C), and FIGS. 6 and 7 show the structure of the cam and the outermost track position detection mechanism. Explanatory drawings showing the structure and operation. Figure 8 is an exploded perspective view of the cassette loading mechanism. Figure 9 is a perspective view of the assembled cassette loading mechanism. Figure 10 is a sectional view of the cassette loading mechanism immediately after inserting the cassette. , FIG. 11 is a cross-sectional view of the cassette mounting mechanism in a fully installed state, and FIG. 12 (A)
-(6) are explanatory diagrams showing the operation of the rollers during the cassette mounting operation, FIG. 13 is a sectional view of the cassette mounting mechanism before the cassette f is lowered, FIG. 14 is a sectional view of the cassette mounting mechanism after the cassette is lowered, and FIG. Fig. 15 is a perspective view showing the relationship between the cassette mounting mechanism and the chassis, Fig. 16 is a perspective view of the chassis with the cassette mounting mechanism attached, and Fig. 1
Figure 7 is an explanatory diagram showing the arrangement of the board on which the control circuit is mounted, Figure 18 is a side view of the chassis with the board installed, and Figure 1
Figure 9 (A) is a block diagram of the control circuit, Figure 19 (B) is a diagram showing the relationship between the rotation speed of the media and the reproduction output, and Figure 2
Figure 0 (A) is an explanatory diagram of tracks on a magnetic disk, No. 20.
Figure CB) is an explanatory diagram of roughly recorded tracks, and Figure 20 (
C) is an explanatory diagram of densely recorded tracks, FIG. 20 (D
) is an explanatory diagram of the recording method adopted by the present invention, and FIG. 21 (A
) to (C) are diagrams showing reproduction output characteristics corresponding to the recording states shown in FIGS. 20(B) to (D), respectively, and FIG. 22(
A) is a plan view of the magnetic head, FIG. 22 (B) is a sectional view taken along the line DD in FIG. 22 (A), and FIG. 23 (A) is a plan view of the magnetic head.
FIG. 23 (B) is a plan view showing another example of the structure of the second
EE line sectional view of Figure 3 (A), Figure 24 (A), (B)
Figure 25 is an exploded perspective view of the magnetic disk cassette, and Figures 26 (A) and (B) are views with the shutter closed. FIG. 26(C) is a plan view and a side view of the cassette. (D) is a plan view and a side view with the shutter open;
Figure 27 is an enlarged sectional view taken along line F-F of Figure 26 (A),
FIG. 8 is a perspective view illustrating the shutter opening operation. 20...Rotating shaft 26...Cam 27...Gear 93...RB% disk cassette 94...Magnetic disk Corridor ant mechi≧7th turn & rebellion□ Fig. 19 (A) Fig. 20 (A) Figure 20 (B) Figure 21 (A) 1-111-1)
--1'' side R return - Fig. 21 (B) Fig. 21 (C) Upward side 1 - Fig. 22 (A) Fig. 22 (B) No. 18 Fig. 23 (B) 28 No. 26 Figure (A) n Figure 26 (B) +4'/ ljM Figure 26 (C) Figure 26 (D) +41IJ! :1

Claims (1)

[Claims] A magnetic disk device characterized in that the material constituting the magnetic disk and the material constituting the cam for moving the magnetic head are made of materials whose linear expansion coefficients are approximately the same.