JPH02249171A - Pad device for magnetic head - Google Patents

Abstract

PURPOSE:To obtain uniform head touch at inner and outer peripheries by forming the depth of the groove of a groove part for negative pressure generation in a pad device for magnetic head in such a way that an inner peripheral side is always cut deeper than an outer peripheral side against a recording medium. CONSTITUTION:The groove parts 2a and 2b for negative pressure generation are formed on a medium confronting plane in the radial direction of a disk shape recording medium 1, and also, the depth of the groove parts 2a and 2b are formed in such a way that the groove at the inner peripheral side is cut deeper relatively. Since the depth of the groove parts 2a and 2b for negative pressure generation at the inner peripheral side are cut deeper than that at the outer peripheral side against the medium 1 centering a magnetic head, the amount of air that flows in the groove part 2b at the inner peripheral side is increased, and generating negative pressure can be increased. Therefore, it is possible to slide the recording medium 1 with the magnetic head with uniform pressure even at every position extending over from the outer peripheral side to the inner peripheral side. In such a way, satisfactory head touch can be obtained in an entire area in an access direction.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to a pad device for a magnetic head, and more specifically, to a pad device for a magnetic head, and more specifically, to a device for stably sliding a magnetic recording medium rotating at high speed against a magnetic head in a magnetic recording/reproducing device. The present invention relates to a pad device for a magnetic head for contacting the magnetic head.

[Prior Art] As is well known, in a magnetic recording and reproducing device that records and reproduces image information using a recording medium made of a disc-shaped thin flexible magnetic sheet, high-quality recorded images and In order to obtain reproduced images, the recording medium is rotated at high speed relative to the magnetic head, and the magnetic surface of the recording medium rotating at high speed (for example, 3600 rpm) is brought into sliding contact with the magnetic head. This enables high-quality recording and playback operations. In addition, as a means of sliding the recording medium against the head with a constant pressure to obtain a stable head touch, there is a pad called a double front ring, which has a magnetic head in the center and a donut-shaped recess around it. The means is disposed so as to be movable in the radial direction facing the magnetic surface of the recording medium, and generates a negative pressure by the flow of air generated when the recording medium rotates at high speed, and the negative pressure causes the recording medium to There is a pad device for a magnetic head that generates an attractive force such that the magnetic head is attracted to the head.

FIG. 6 shows the main parts of a conventional magnetic recording and reproducing apparatus that records and reproduces image information, etc. on the recording medium 1 by bringing the recording medium 1 into sliding contact with the magnetic head 9 using the above-mentioned negative pressure pad device for the magnetic head. This is an example. In the figure, a magnetic recording medium 1, which is formed into a flexible thin disk shape and has a magnetic surface on its lower surface, is provided with a center hub 11 for chucking in its center, and this center hub 11 is connected to a spindle. It is configured to be chucked onto a spindle shaft 13a of a motor 13. The chucked recording medium 1 is then rotated at high speed in the clockwise direction by the motor 13. A carriage 17 is disposed below the recording medium 1 in parallel to the surface of the medium 1, and a magnetic head is positioned on the upper surface of the center of the carriage 17 near the outer edge (left end in the figure). A magnetic pad device 12 is disposed, and a magnetic head 9 disposed in the center of the pad device 12 slides on the magnetic surface of the lower surface of the recording medium 1. An access motor 14 fixed to a substrate (not shown) moves the recording medium 1 in the radial direction, that is, in the arrow a in the figure.
It is designed to move in the direction. That is, a lead screw (not shown) is attached to the rotating shaft of the access motor 4, and this lead screw is screwed into a moving screw hole (not shown) of the carriage 17. Therefore, when the motor 14 is driven, the carriage] 7 is moved by the lead screw along the guide shaft 15 disposed on the - side edge (the front side in the figure) of the carriage] 7 along the arrow a.
direction, thereby moving the magnetic head 9 towards the recording medium]
slide in the radial direction to access the desired track. Further, a guide plate 16 is provided on a pillar fixed to a chassis board (not shown) to facilitate sliding contact with the pad device 12 when the recording medium 1 starts rotating. 1
It is designed to slide into contact with the top surface of the

FIG. 7 is an enlarged plan view of the pad device 12, and FIG. 8 is a cross-sectional view taken along the line AA in FIG. 7. As shown in each figure, the pad device 12 is 1. )) has a structure in which double rings, an outer ring 12a and an inner ring 12b, are protruded from a short cylindrical base block 10 toward the magnetic recording medium 1. ,
A ring-shaped concave portion 1.2c for generating negative pressure is formed between the two wings 12a12b. In the center of this pad device 12 is a square hole 1 in which the magnetic head 9 is buried.
2d is formed.

Furthermore, the dimensions of each part of the pad device 12 are as follows:
For a recording medium with a diameter of 2 inches, in the case of the conventional example shown in FIGS. 7 and 8, for example, the outer diameter d1 is 7 mmφ, the inner diameter d2 of the outer ring 1.2a is 6 mmφ, and the inner ring 1 is 7 mmφ.
2. The outer diameter d3 of b is 3.5. wφ, the length of one side of the square hole 12d in which the magnetic head 9 is embedded is d4 or 2 mm %
It becomes. Further, the depth d7 of the concave portion 12c is set to, for example, about 50 microns, whereas the depth d8 of the magnetic head 9 of the head top 9a is d5×d6.
is on the order of several hundred microns.

In the conventional magnetic recording main device configured as described above, in order to record and reproduce image information etc. on the recording medium 1 by the magnetic head 9, as shown in FIG.
When the center hub 11 is chucked onto the spindle shaft 13a of the spindle motor 13 and the spindle motor 3 is rotated, the recording medium 1 is accordingly rotated at high speed. Then, negative pressure is generated between the recording medium 1 and the pad device 12, and this negative pressure causes the recording medium 1 or the pad device 1 to
The magnetic head 9 embedded in the pad device 12 comes into sliding contact with the recording medium 1.

In this way, conventional pad devices generally have a space formed around the magnetic head, and are provided around the space to face the recording medium together with a magnetic head. (Refer to Publication No. 59-54071).

However, in such a conventional pad device, the actual 8111 data has revealed that the running of the recording medium becomes unstable on the downstream side in the running direction. The reason for this is that, as will be explained later, due to the structure of the pad device, the air pressure is uniformly negative between the pad device and the recording medium, and positive pressure is generated in a part of the downstream side in the running direction. This seems to be due to Therefore, in a recording/reproducing apparatus having such a pad device, it is difficult to obtain a stable contact state between the magnetic head and the recording medium.

That is, when the recording medium 1 is caused to run in the direction indicated by the arrow X with respect to the pad device] 2, the pad device 12
Since a flow is generated in the air between the recording medium and the recording medium, pressure is generated between the two. Therefore, when we performed a hydrodynamic simulation and investigated the pressure distribution on the opposing surface between the pad device 12 and the recording medium 1, we found that the 9th
The result will be as shown in the figure. In the pressure distribution diagram of FIG. 9, the horizontal axis is the center line A-A of the pad device 12 shown in FIG.
Corresponding to the positions of each of the points P1 to P8 above, the vertical axis represents the pressure between the recording medium 1 and the recording medium 1. In this graph, 0
The point becomes pressure O, that is, atmospheric pressure. As is clear from FIG. 9, the area upstream in the running direction from the protruding surface of the inner ring 12b of the pad device 12 (point P
1 to P6), the air pressure is a negative pressure lower than atmospheric pressure, but the groove of the concave portion located on the downstream side in the traveling direction], 2c and the medium slide which is the protruding surface of the outer ring 12a Positive pressure is present in the area of the contact surface (area of points P6 to P8). For this reason, the pad device 12 and the recording medium 1 are not stably attracted to each other in the downstream area, and the running of the medium 1 becomes unstable. Actual measurement data also reveals that in the downstream region where the pressure is positive, the recording medium 1 vibrates, causing so-called fluttering, and is significantly deviated from stable running. The reason why the above positive pressure occurs is that the groove 1
This is thought to be due to the fact that the airflow becomes stagnant on the downstream side of 2c, which increases the pressure in the downstream area.

Therefore, the present applicant first proposed a pad device that eliminates the drawbacks of the conventional pad device 12 described above in Japanese Patent Application No. 6:3-64799.
proposed by No.

This pad device, as shown in FIGS. 10 and 12,
A part 12g located on the downstream side of the outer ring-2a in the conventional pad device 12 is connected to the square hole recess 12 of the head installation part.
The deletion corresponds to the length d4 of one side of d, but
It is not necessarily necessary to correspond.

With this configuration, as the recording medium 1 runs, the air in the space is dragged by the recording medium 1 and the notch 12g
Since the amount of air flowing out from the space and flowing into the space is smaller, a negative pressure is generated throughout the space as shown in FIG.
As shown in the figure, it is well absorbed by the pad device and comes into close contact with the magnetic head 9.

[Problems to be Solved by the Invention] By the way, the conventional pad device described above and the pad device proposed by the present applicant in which a part of the downstream side is missing have a magnetic head 9 disposed in the center, and a magnetic head 9 arranged around the magnetic head 9. Pressure generating groove 12c
However, the depth of the groove portion is constant on the upstream and downstream sides of the disk-shaped recording medium 1 in the rotational direction, and on the outer and inner circumferential sides of the medium 1. Therefore, the following problems occur.

That is, the recording medium 1 is formed of a flexible sheet-like disk, and its center portion is fixed to a center hub 11 (see FIG. 6) for chucking onto a spindle shaft. For this reason, the recording medium 1 rotated at high speed is deflected from the outer circumference to the inner circumference, that is, from the center.
<If the same negative pressure suction force as on the outer circumferential side is used, it becomes difficult to make sliding contact with the magnetic head. In other words, the closer to the inner circumference the medium is, the stronger the rigidity of the medium becomes, making it difficult for the medium to bend toward the head. Furthermore, the closer to the inner circumference, the slower the relative speed with the medium (peripheral speed) and the lower the absolute value of the negative pressure.

As described above, since there is a difference in the relative speed between the magnetic head and the recording medium between the outer circumferential side and the inner circumferential side with the magnetic head moving in the radial access direction of the recording medium, the negative pressure generation groove is If the depth is made constant, it is difficult to always obtain stable head touch from the outer circumferential side to the inner circumferential side. In addition, especially in the case of a head with two or more head gaps, such as a multi-head, it is difficult to achieve equal head touch for all channels, resulting in unstable contact and making it difficult to perform good recording and playback operations. It disappears.

On the other hand, when the magnetic surface of a magnetic recording medium rotating at high speed is attracted by negative pressure by the magnetic head pad device and brought into sliding contact with the magnetic head, the initial attraction force cannot be generated by the conventional negative pressure generating groove alone. Not enough. Once the medium is brought into sliding contact with the magnetic head, the suction force due to the generated negative pressure must be maintained stably, or the suction force due to the generated negative pressure must be strong when the medium is first attracted. However, with the negative pressure generating groove in the conventional pad device, it is not possible to immediately suck the recording medium when the recording medium starts, and there is a delay in the suction action.

The main purpose of the present invention is to eliminate the above-mentioned problems of the conventional pad device, and to always generate a uniform negative pressure for sucking the medium both on the outer circumference side and the inner circumference side of the pad device, and in the access direction. An object of the present invention is to provide a pad device for a magnetic head that can provide a good head touch over the entire range.

Another object of the present invention is to provide a pad device for a magnetic head that has a suction leading groove that can immediately attract a recording medium and bring it into sliding contact with a magnetic head even in the early stages of running the magnetic recording medium. It is in.

[Means for Solving the Problems] A pad device for a magnetic head according to the present invention has a groove for generating negative pressure formed in the radial direction of the disc-shaped recording medium on the medium facing surface, and the depth of the groove is set to be circular. Regarding the plate-shaped recording medium, the plate-shaped recording medium is formed to be relatively deeper as it is located on the inner circumference side, and the negative pressure generating 2 is formed on the upstream side with respect to relative movement with the recording medium. It is characterized in that a relatively deep leading groove is formed.

[Function] Since the depth of the negative pressure generating groove is deeper on the inner circumferential side of the medium than on the outer circumferential side with the magnetic head as the center, the amount of air flowing into the groove on the inner circumferential side is larger. The generated negative pressure is large, and this allows the recording medium to slide into equal pressure against the magnetic head at any position from the outer circumferential side to the inner circumferential side, and is also generated in the leading groove at the beginning of the medium's travel. Since the medium is immediately suctioned by the negative pressure, there is no delay in the suction action.

[Example] The present invention will be explained below with reference to illustrated embodiments.

FIGS. 1A to 1D show a first embodiment of the present invention. This magnetic head pad device 2 is shown in FIG.
As shown in A), the carriage (not shown) is arranged so that its planar shape is an elongated ellipse, and its short side is located along the rotational direction of the recording medium 1, and its long side is located along the access direction Y of the head 9. ) The base body is formed by the block body 2A disposed on the top.

A magnetic head 9 is buried in the center of the medium facing surface of the block body 2A by appropriate means, and is disposed so as to protrude upward from the magnetic gap. Then, on the medium facing surface of the block body 2A, at each position equidistant from the front side and the rear side in the access direction Y with the magnetic head 9 as the center, there are provided a downstream side in the medium rotation direction X from approximately the center of the medium facing surface. Grooves 2a and 2b for generating negative pressure are respectively bored toward the grooves 2a and 2b. That is, both grooves 2a for generating negative pressure are provided on the medium facing surface at positions that are spaced apart in the radial direction of the disk-shaped recording medium, sandwich the magnetic head 9, and correspond to the inner circumferential side and the outer circumferential side with respect to the medium.
, 2b are drilled.

The grooves 2a and 2b have different depths as follows. That is, as shown in FIG. ) is the depth h2 of the other groove 2a (first
(see figure (D)), and is formed so as to satisfy the relationship h1≧h2.

A leading groove 2 is provided at a position on the upstream side of the medium facing surface of the block body 2A along the access direction Y.
C is drilled. That is, this leading groove 2c performs a triggering action for sucking the medium, and is similar to the negative pressure generating groove 2c.
The grooves 2c are bored in a direction intersecting the upstream extension lines of the grooves a and 2b, and the depth of the grooves 2c is relatively deep, and is approximately the same depth as the other groove 2a on the outer peripheral side.

In the bat device 2 of the first embodiment configured as described above, the negative pressure generated in the groove of the negative pressure generating groove portion 2b on the front h' side (inner peripheral side of the medium) in the head access direction Y is Since the negative pressure generated in the negative pressure generation groove 2a on the side (outer circumferential side of the medium) is always greater than that generated in the groove, the medium on the inner circumferential side, which is less likely to bend than the outer circumferential side due to its strong suction force, is moved in the same way as the outer circumferential side. Therefore, a constant negative pressure can be created on the inner and outer circumferential sides in the access direction Y, and thereby the medium 1 can be brought into stable sliding contact with the magnetic head 9.

Furthermore, since the medium 1 is sucked by the negative pressure generated in the leading groove 2c before the negative pressure for sucking the medium is generated by the negative pressure generating groove 2a2b, there is no delay in the suction action at the beginning of the medium traveling, and the process is smooth. The media suction action is performed.

FIGS. 2(A) and 2(B) show a second embodiment of the present invention. This magnetic head pad device 3 has a block body 3A having a planar shape similar to that of the pad device 2 of the first embodiment.
(Refer to FIG. 1 (A)) The only difference is that the operation and effect are exactly the same.

That is, the planar shape of the block body 3A is such that the upstream half is triangular and the downstream half is vertically rectangular. A leading groove 3c is drilled in the area, and a magnetic head 9 is buried in the central position on the downstream side, and the magnetic head 9 is located at the same distance between the front side (inner circumference side) and the rear side (outer circumference side) in the access direction. , negative pressure generating grooves 3a and 3b are bored from the center toward the downstream side. Of both grooves 3a and 3b, the depth of the groove 3b on the front side (inner periphery side) is deeper than the depth of the groove 3a on the rear side (outer periphery side), and the leading groove 3C The depth of the groove 3a is
are formed to the same extent.

Even with this configuration, it functions in exactly the same way as the pad device 2 of the first embodiment.

Next, the pad devices according to the third and fourth embodiments of the present invention shown in FIGS. 3 and 4 will be explained. The pad device 4 for a magnetic head according to the third embodiment of the present invention shown in FIG.
Negative pressure generating groove 2a in the pad device 2 of the first embodiment (see FIG. 1).

The magnetic head pad device 5 of the fourth embodiment of the present invention shown in FIG. 4 is similar to the second embodiment (FIG. reference)
The negative pressure generating grooves 3a and 3b in the pad device 3 are extended and communicated with the leading groove 3C by crossing them.

Exactly the same effects can be obtained even if each structure is configured in this manner.

FIG. 5 shows a fifth embodiment of the magnetic head pad device of the present invention. This pad device 6 includes the first
The present invention is applied to a magnetic head pad device 12 previously proposed by the applicant shown in FIGS. 0 and 12.

That is, this pad device 6 is formed by protruding a double ring consisting of an outer ring 6a and an inner ring 6b on the medium facing surface of a short cylindrical base block body 6A. A ring-shaped negative pressure generating groove 6c formed between the grooves 6b is formed so as to gradually become deeper from the outer circumferential side to the inner circumferential side, as shown in the central vertical cross-sectional view of FIG. 5(B). There is. As shown in the central cross-sectional view of FIG. 5(C), a leading groove 6e is bored on the upstream side. The magnetic head 9 is embedded in the center of the inner ring 6b, and the outer ring 6a has a notch 6d, similar to that shown in FIG. 1012.

Of course, even with this configuration, the pad device functions in exactly the same way as the pad device of each of the embodiments described above.

Further, FIG. 5(D) shows a modification of the fifth embodiment. This modification of the magnetic head pad device 6
′, a deep groove portion 6 formed on the inner peripheral side of the negative pressure generation groove portion 6C and serving as the leading groove portion 6e.
f is provided between the upstream side and the inner peripheral side, and the same deep groove portion 6
Groove 6g at a position opposite to f, that is, between the downstream side and the outer peripheral side
is formed in a shallow groove.

Even in this manner, the pad device can obtain exactly the same effects as the pad devices of the respective embodiments described above.

[Effects of the Invention] As described above, according to the present invention, the depth of the negative pressure generating groove in the magnetic head pad device is set so that the inner circumference side is deeper than the outer circumference side with respect to the recording medium. Since the head is formed to have a strong negative pressure for suction toward the inner circumference, a uniform head touch can be obtained at the inner and outer circumferences, and the drawbacks of this type of conventional device can be overcome.

In addition, all channels can easily make good head contact with a magnetic head such as a multi-head with two or more heald gaps, and furthermore, it becomes easy to make good head contact with a magnetic head such as a multi-head that has two or more helad gaps. The leading groove also provides a remarkable effect in that it can be carried out without delay in operation.

[Brief explanation of drawings]

FIGS. 1(A) to (D) show a first embodiment of the present invention]9 A pad device for a magnetic head, in which FIG. 1(A) is a plan view and FIG. 1(B) is a pad device for a magnetic head. Bottom view, Figure 1 (C) and 1
Figure (D) is a cross-sectional view taken along lines CC and D-D in Figure 1 (A), and Figures 2 (A) and (B) are magnetic diagrams showing a second embodiment of the present invention. Plan view of head pad device and IIBIIB
The sectional views taken along the line, FIGS. 3 and 4 show the third and fourth embodiments of the present invention.
5(A), (B), and (C) are plan views of a magnetic head pad device showing a fifth embodiment of the present invention, and VBVB. 5(D) is a plan view of a pad device for a magnetic head showing a modification of the fifth embodiment, and FIG. 6 is a sectional view taken along a line VC-VC. FIG. 7 is a perspective view of a main part showing an example of a magnetic recording/reproducing device using a pad device, and FIG.
FIG. 8 is a sectional view taken along line A-A in FIG. 7, and FIG. 9 is a plan view of the magnetic head pad device shown in FIGS. 7 and 8. The pressure distribution diagram, Figure 10, shows the negative pressure generation status of the device.
FIG. 11 is a plan view of a magnetic head pad device previously proposed by the applicant; FIG. 11 is a diagram showing the negative pressure generation situation of the pad device shown in FIG. 10; FIG. It is a sectional view along the AA line. 1...... Disk-shaped recording medium 2.3, 4, 5, 6.12...... Pad device for magnetic head

Claims (2)

[Claims] (1) A negative pressure generating groove is formed on the medium facing surface in the radial direction of the disk-shaped recording medium, and the depth of the groove is set such that the deeper the groove is located on the inner circumference side of the disk-shaped recording medium, A pad device for a magnetic head, characterized in that it is formed to be relatively deep. (2) A groove for generating negative pressure is formed in the radial direction of the disc-shaped recording medium on the medium facing surface, and the depth of the groove is adjusted so that the depth of the groove is adjusted so that the inner circumference of the disc-shaped recording medium is smaller. A pad device for a magnetic head, characterized in that a relatively deep leading groove is formed upstream of the negative pressure generating groove with respect to relative movement with a recording medium.