JPH0770139B2 - Rotating magnetic sheet device - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a flexible and rotationally driven magnetic record carrier,
For example, the present invention relates to a rotating magnetic sheet device for recording and reproducing various digital signals as video signals on a magnetic sheet.

2. Description of the Related Art A conventional rotating magnetic sheet device needs to rotate a magnetic sheet at a high speed, for example, 1800 to 3600 rpm in order to record and reproduce a high frequency, and the magnetic sheet and the magnetic head are in stable contact with each other. Is an essential condition. For this reason,
The pad for pressing the magnetic sheet against the magnetic head forms an air film between the magnetic sheet and the magnetic sheet rotating at a high speed to bring the magnetic sheet into a non-contact state to stabilize the contact between the magnetic sheet and the magnetic head and the pad of the magnetic sheet. Prevent friction,
It has been proposed to ensure longevity.

FIGS. 4, 5, and 6 show a conventional rotary magnetic sheet device. FIG. 4 shows a rotating magnetic sheet apparatus including a flexible magnetic sheet 1, a magnetic sheet rotating motor 2, a magnetic head 3 and a pad 4, and FIG. 5 shows a rotating direction of the magnetic sheet 1 with respect to the magnetic head 3. Is provided on the upstream side of the magnetic sheet 1 in parallel with the rotation plane of the magnetic sheet 1, and on the downstream side in the rotation direction, the pressure plane A is perpendicular to the straight line connecting the magnetic head 3 and the rotation center of the magnetic sheet 1 to the rotation plane. The structure of the pad 4 provided with the inclined surface B inclined in the direction is shown. Further, as shown in FIG. 6, specific constitutional conditions are also proposed. That is, the angle θ ₁ of the inclined surface B is 2 ° to 3 °, the angle θ ₂ of the inclined surface B ′ is 4 ° to 13 °, and the position d ₁ indicating the position of the head 3 is 2.
The position of 5 to 5 mm and the d ₂ position is 2.5 to 7 mm, and the magnetic head 3 is inserted in an appropriate amount on the pad 4 side with respect to the lower surface of the pad 4.

The shape of the pad 4 and the arrangement condition of the head as described above are as follows.
Particularly, the inclined surfaces B and B'are connected to the rear surface D of the pad 4, and the positive pressure generated between the inclined surfaces B and B'and the rotating magnetic sheet 1 is increased to increase the inclined surfaces B and B ', that is, the pad 4 The contact between the magnetic sheet 1 and the magnetic sheet 1 during rotation is more reliably eliminated, and the good contact state between the pad 4 and the head 3 and the long life of the magnetic sheet 1 are ensured.

Problems to be Solved by the Invention However, the conventional device has the following problems in terms of the above-described pad configuration conditions in terms of mass production and stable head contact. That is, in FIG. 5, the parts that greatly affect the good head contact between the head 3 and the magnetic sheet 1 are the height of the end P ₂ of the pressing surface A and the end P ₃ of the inclined surface B with respect to the magnetic sheet. It is high. This is because, said portion of the P ₂ and P ₃ is the position where the magnetic sheet 1 are closest, the head 3 as seen in FIG. 5'll press the magnetic sheet 1, the magnetic sheet 1 in the P ₂ and P ₃ This is because when the heights of P ₂ and P ₃ change, the contact angle of the magnetic sheet 1 with respect to the head 3 changes and the pressure applied to the head changes. Furthermore, the pressing surface must be parallel to the plane of rotation of the magnetic sheet 1. Therefore, the portion P ₃ is also the pressing surface A, that is, P ₂
If the heights of the portions are not the same, the magnetic sheet 1 cannot contact the magnetic head 3 at a symmetric and stable contact angle, and the best contact condition cannot be established. That is, it is an important condition that the point P ₃ is located on the extension of the pressing surface A. In contrast to this condition, for example, when the pad 4 shown in FIG. 5 is formed by resin molding or cutting, if the accuracy of the rear surface D of the pad 4 varies, the inclined surface B inclines, and the height of P ₃ also varies. It becomes a big problem as mentioned above.

Further, when the pad 4 is set at a predetermined accurate position with respect to the head 3, it is necessary to set the position by pressing the pad 4 against a jig while using the pressing surfaces A and P ₃ as guide surfaces in the mass production process. . In such a case, since the inclined surface B is inclined, the portion of P ₃ contacting the jig becomes a substantially corner portion and contacts at a point or a line. In the material of No. ₃ , scratches, burrs, etc. are generated in the P ₃ part, and when the magnetic sheet 1 rotates, it becomes difficult for the air film of the P ₃ part and the magnetic sheet 1 to be formed. There is also a problem that the contact with 3 becomes unstable.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention is characterized in that a minute plane is provided at the end of the inclined surface, and the minute plane is set on an extension line of the pressing surface. To do.

Effect As described above, in the present invention, since the minute plane is provided, the height of the minute plane does not change even if the rear surface has an error in cutting or molding, and good head contact is possible. Since it is provided and disposed on the extension of the pressing surface, it can be used as a guide surface for the assembly jig by forming a reference surface for the head together with the pressing surface. In particular, since the area of the minute plane is a plane even if the area is small, damage such as scratches and chips is reduced. Therefore, variations in pad position accuracy can be reduced in the assembly of the magnetic sheet and the pad, and even if variations in mass production occur, there is a margin of head pushing amount, and a good contact state between the magnetic head and the magnetic sheet is secured. It is also possible to prevent damage to the magnetic sheet due to contact of the pads.

Embodiment An embodiment of the present invention will be described below with reference to the drawings.

1 to 3 show an embodiment of the rotating magnetic sheet device of the present invention. Also in the apparatus of this example, the pad 4 and the magnetic head 3 are arranged so as to face each other with a predetermined gap therebetween, and the magnetic sheet 1 which is rotationally driven is arranged between them. First
FIG. 2 and FIG. 2 show the structure of the pad 4, which is the main point of the present invention. As shown, the pad 4 has an inclined surface B that is inclined so as to narrow the gap toward the downstream side in the rotation direction of the magnetic sheet 1 with respect to the rotation plane of the magnetic sheet 1. The pressing surface B has a predetermined arc R ₂ , and the inclined surface B is provided with a minute plane C parallel to the rotation plane of the magnetic sheet 1 at the end. Also, the minute plane C
Is arranged on the extension line of the pressing surface A, and the pressing surface A and the minute plane C can be arranged parallel to the rotation plane of the magnetic sheet 1. Further, the position of the falling portion P ₁ of the arc R ₂ of the inclined surface B is arranged to be located approximately at the midpoint of the distance between the minute plane C and the end portion P ₂ of the pressing surface A.

Further, the magnetic head 3 is installed at a slight distance L _{5 with} respect to the falling portion P ₁ of the arc R ₂ of the inclined surface B. The distance L ₅ is not an absolute condition, and even if the distance is 0, the contact state between the head 3 and the magnetic sheet is within the practical range. See also L ₅
Can be used even if becomes a minus value. Further, the L ₅ will be described in detail. FIG. 3 is a schematic diagram showing a contact position relationship between the head 3 and the magnetic sheet 1. In FIG. 3, C represents the position of the small plane C shown in FIG. 2, also P ₂ shows the same position as P ₂ of FIG. 2, the magnetic sheet 1 is pushed up by the head 3 the C and P ₂
The magnetic sheet 1 is supported by an air film generated between the magnetic sheets 1. However, in order to obtain a good contact state between the head 3 and the magnetic sheet 1, the distances L ₄ and L ₃ shown in the figure are substantially the same. Therefore, it is desirable that the contact angle of the magnetic sheet 1 with respect to the head 3 be symmetrical. As shown in FIG. 2, since the air film is also formed on the inclined surface B, the magnetic sheet 3 is set so that the point C supporting the magnetic sheet 1 is substantially in the direction of C'as shown in FIG. Will be. Therefore, as described above, the head 3 is about 1/2 the distance between C and C '.
That is, a better head contact state can be obtained by moving L in the figure.

Next, the dimensional relationship of each component will be described.

In FIG. 2, it is desirable that the dimensions obtained by the experimental examination be as follows.

L ₁ = 0.2 to 0.4 [mm] L ₃ = 3 to 6 [mm] L ₄ = 3 to 6 [mm] L ₅ = 0 to 2 [mm] θ = 2 ° to 3 ° R ₂ = 10 to 20 [ mm] Incidentally, the above dimensional range is a desirable value, and even if the range is slightly changed, there is sufficient margin for practical use.

It should be noted that L ₄ is set to a size sufficiently larger than L _{1 so} that a sufficient positive pressure is applied between the inclined surface of L ₄ and the magnetic sheet, and when the value of L ₁ becomes large, the magnetic sheet Since the action of attracting 1 to the side of the minute plane C is increased and the magnetic sheet is likely to contact at the intersection of the inclined surface B and the minute plane C, the above dimensional condition should be as small as possible.

However, when the above dimension L ₁ is brought close to 0, P3 in FIG.
The part becomes an acute angle, and this part P3 is pressed against the position setting jig, or it is lightly contacted with something by other handling and P3
Since the part comes into contact with lines or points, there arises a problem that chips or scratches occur.

As a countermeasure, the above-mentioned problem can be dramatically improved by setting the above dimension L ₁ to about 0.1 to 0.2 mm. On the actual surface, by setting the above-mentioned dimension L ₁ , light is reflected on the microscopic area C, and it is possible to easily visually check for cracks and scratches.
The neighborhood is set as the desired minimum value.

Next, the setting of the maximum value 0.4 mm of the dimension L ₁ will be described.In order to secure the minimum value 0.2 mm of the dimension L ₁ described above, it is necessary to set the range of L _{1 in} consideration of the processing accuracy. Yes, in resin molding and cutting, as a result of applying general processing accuracy of ± 0.1 mm in consideration of mold accuracy, shrinkage of pad material, and manufacturing cost, in order to secure 0.2 mm of L ₁ above, 0.3 The processing accuracy is ± 0.1 mm.

That is, the finish is in the range of 0.2 to 0.4 mm, and the maximum value of the dimension L ₁ is set to 0.4 mm. Note that arc R ₂
Also exhibits its function in the shape of a slope instead of a circular arc, but when the slope is used, a corner is formed at the intersection with the slope B, and the surface runout of the magnetic sheet 1 and the pressing amount of the magnetic head 3 to the pad 4 are reduced. When it becomes large, the above-mentioned angle and the magnetic sheet 1 are likely to come into contact with each other, which often causes damage.

1 and 2, when the magnetic sheet 1 is not rotating, the magnetic sheet 1 and the pad 4 are in contact with each other.
When the magnetic sheet 1 is rotated in the direction of arrow E at a predetermined number of revolutions as shown in the figure, the magnetic sheet 1, the pressing surface A, the inclined surface B, and the minute plane C are acted by the action of the airflow that is rotated together with the magnetic sheet 1.
A stable air film is generated between and. as a result,
The magnetic sheet 1 is pressed against the magnetic head 3 without contacting the pad 4. At this time, the magnetic sheet 1 is deformed into a saddle shape in the vicinity of the magnetic head 3 and comes into a shape that abuts on the magnetic head 3 well. Further, the saddle shape increases the rigidity of the magnetic sheet 1 in the vicinity of the magnetic head 3, the vibration of the magnetic sheet 1 becomes extremely small, and the curl of the magnetic sheet 1 is corrected. As a result, stable contact between the magnetic sheet 1 and the head 3 can be obtained.

EFFECTS OF THE INVENTION As described above with reference to the embodiments, the present invention is a rotary magnetic device in which a pad and a magnetic head are arranged so as to face each other with a predetermined gap, and a magnetic sheet is arranged between the pad and the magnetic head. In the sheet device, a pressing surface A for pressing the magnetic sheet is provided on the upstream side of the magnetic head of the pad in the rotation direction of the magnetic sheet, and the pressing surface A is configured to be parallel to the rotation plane of the magnetic sheet. An inclined surface B is provided on the downstream side of the rotation direction of the pad so as to narrow the gap toward the downstream side of the rotation direction of the magnetic sheet with respect to the rotation plane. A small area C parallel to the plane of rotation of the magnetic sheet is provided at the downstream end, and the inclined surface B sets the length of the magnetic sheet in the rotation direction to the minute plane C to be large. By setting the length of the minute plane C in the same direction to be 0.2 to 0.4 mm, almost the entire surface of the pad on the downstream side in the magnetic sheet rotation direction is formed by the inclined surface B, and the positive pressure by the inclined surface B is increased. It is possible to easily secure the set dimension of the pad that can press the magnetic sheet against the head in a good state while ensuring the feature of reliably eliminating the contact between the magnetic sheet and the pad. That is, by providing the minute area C, the height of the end portion of the inclined surface B, which is an important portion of the pad for obtaining a good contact state of the head, can be precisely formed or cut, and the pad with respect to the head can be processed. It can be used without damage even if it comes into contact with a jig etc. as a reference surface during assembly for position setting.

The concave surface A and the minute plane C parallel to the rotation plane of the magnetic sheet are provided, and the minute plane C is provided on the extension line of the pressing surface A.
Since these two points serve as reference surfaces and are easily pressed in parallel with the magnetic sheet by the setting, contact with the magnetic sheet due to inclination of the pressing surface A or the like does not occur, and a stable head and magnetic sheet are provided. The contact state is obtained. Further, since the two planes, that is, the pressing surface A and the minute plane C have the same height and are parallel to each other, the accuracy can be easily confirmed and the position setting with respect to the head can be performed very easily.

The minute plane C has a length in the rotation direction of the magnetic sheet of 0.2 to
Since it is set to a very small dimension of 0.4 mm, and the length of the inclined surface B is set to be larger than that of the minute plane C, the positive pressure generated between the magnetic sheet and the inclined surface B becomes large, and the inclination is increased. The air flow (air film) between the surface B and the magnetic sheet is not disturbed, and the suction force acting on the minute plane C is extremely small, so that the magnetic sheet can be reliably magnetized without being brought into suction contact. The sheet can be rotated and the above-mentioned effects can be obtained.

As described above, according to the present invention, it is possible to realize a circuit magnetic sheet device having a head contact condition with extremely high reliability and good mass productivity.

[Brief description of drawings]

FIG. 1 is a schematic diagram relating to a pad showing an embodiment of a rotating magnetic sheet device according to the present invention, FIG. 2 is a dimensional relational diagram of a main part of the device, and FIG. 3 is a diagram explaining the action of the pad on the magnetic sheet. FIG. 4 is a perspective view showing a conventional rotating magnetic sheet device, FIG. 5 is a schematic diagram relating to pads of the conventional device, and FIG. 6 is a dimensional relationship diagram of pads of the conventional device. 1 ... magnetic sheet, 3 ... magnetic head, 4 ... pad,
A ... Pressing surface, B ... Sloping surface, C ... Slightly flat surface.

Claims (1)

[Claims] 1. A rotary magnetic sheet device in which a magnetic head and a pad are arranged at positions facing each other via a rotating magnetic sheet, wherein the pad has the magnetic sheet on the upstream side in the rotating direction of the magnetic sheet. The magnetic sheet has a pressing surface configured to be parallel to the rotational plane of the magnetic sheet that is pressed toward the head side, and the downstream side of the magnetic sheet in the rotational direction of the rotational direction of the magnetic sheet with respect to the rotational plane of the magnetic sheet. A minute plane parallel to the plane of rotation of the magnetic sheet, which has an inclined surface inclined so as to narrow the gap toward the downstream side, and at the downstream end of the inclined surface in the rotation direction of the magnetic sheet. The inclined surface has a large length in the rotation direction of the magnetic sheet with respect to the minute plane, and the length of the minute plane in the rotation direction of the magnetic sheet is approximately 0.2 mm to 0.4 mm. A rotating magnetic sheet device characterized by being set.