JPH0426905A - Magnetic head device - Google Patents

Abstract

PURPOSE:To maintain high performance and high reliability over a long period by constituting the contact face of a second magnetic head so that the wear resistance to a magnetic tape can be improved rather than that of the contact face of a first magnetic head. CONSTITUTION:By enlarging head width Ct2 of a second magnetic head 6 rather than that of a first magnetic head 5, the contact face between the second magnetic head 6 and the magnetic tape is enlarged and the contact pressure only of the second magnetic head 6 is decreased so as to suppress the head wear amount of the second magnetic head 6. Therefore, the decrease of gap depth G2 of the second magnetic head 6 can be suppressed. In this way, by enlarging the head width of the second magnetic head 6 rather than that of the first magnetic head 5, time to eliminate the gap depth G2 of the second magnetic head 6 can be prolonged, and the service life of the second magnetic head 6 can be made as long as that of the first magnetic head 5. Thus, the service life of a VTR can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention is applicable to, for example, a home video cheap recorder (hereinafter referred to as V
The present invention relates to a magnetic head device installed in a magnetic recording/reproducing device such as a magnetic recording/reproducing device (abbreviated as TR).

[Conventional technology]

The performance and functions of VTRs have improved significantly in recent years, and the development of magnetic head devices, which are a key part of VTRs, is becoming more and more popular.

Figure 9 is a layout diagram of a general magnetic head device of a conventional VTR. reel(
The magnetic tapes (5) and (6) stored in the magnetic tape (4) are attached to one end of the rotating body (3) via the head base (7) and arranged in parallel in the running direction of the magnetic tape (1), And of the first and second magnetic heads that slide on the magnetic tape (1) to perform recording and reproduction, the first magnetic head (5) is located temporally after the running of the magnetic tape (1). However, the second magnetic head (6) is used during special recording and reproduction, for example, 3x mode, and the second magnetic head (6) is used during normal recording and reproduction, and the first magnetic head (5) and the second magnetic head (6) Another pair of magnetic heads (5
)(6) are similarly attached.

In addition, the first magnetic head (5) and the second magnetic head (
6), as shown in FIG. 10, the tips of the first magnetic head (5) and the second magnetic head (6) are moved by a predetermined amount from the head window (3a) provided in the rotating body (3). It is attached to the rotating body (3) via the head base (7) so as to protrude.

In Figure 10, (8) and (9) are I-type cores made of magnetic materials such as ferrite, and (10 and 11) are 5i cores.
Cab, tube, (12) made of non-magnetic material such as 02
(13) is composed of a magnetic material such as ferrite, and includes each of the above I-type cores (10) (1]) and a coil (not shown).
The C-shaped core (8) → gap (lO) → CC cocoa 12) is joined to form the winding windows (14) and (15) for winding the I-shaped core (9). )-gap (11)→CC cocoa 13) constitute two closed magnetic circuits. (16) (17) is the I-shaped core (8) (
9) and the C-shaped cores (12) (13) are glass grooves formed in the C-shaped cores (12) (13) and filled with welded glass.

The recording/reproducing mechanism in the magnetic head device configured as described above will be explained below. Magnetic head (5) (6
) mounted thereon rotates in the direction (a) in FIG. 10, and the magnetic tape (1) runs from the supply reel (2) in the direction (b), ), and in a sliding state with the magnetic spatulas (5) and (6), recording is performed by the second magnetic head (6) during normal recording, and transferred to the take-up reel (4). On the other hand, during special recording, recording is performed using the first magnetic head (5).

Then, playback is performed using a magnetic head (
5) In the sliding state between (6) and the magnetic tape (1), the signal written on the magnetic tape (1) by the first magnetic head (5) is reproduced by the first magnetic head (5). Similarly, the signal written by the second magnetic head (6) is reproduced by the second magnetic head (6).

However, in the magnetic l\jitter arrangement configured as described above, the magnetic tape (1) and the magnetic head (5
) and (6) at a high relative speed of several m/s to several tens of m/s, the magnetic tape (1) moves at the tip of the first magnetic head (5) as shown in FIG. The problem was that the recording and playback characteristics deteriorated. As a way to solve this problem,
A magnetic head device as shown in Japanese Patent No. 04 has been proposed. FIG. 12 shows the configuration of this magnetic head device, in which the radius of curvature (R2) of the sliding side end of the magnetic tab (1) of the first magnetic head (5) is )
The relationship between the radius of curvature of the first magnetic head (5) and the second magnetic head (6) is expressed as R, >R2.

In a magnetic head device having such a configuration, it is possible to prevent air from flowing into the contact surface between the first magnetic head (5) and the magnetic tape (1).
It is possible to prevent deterioration of characteristics during recording/reproducing of the first magnetic head (5) due to floating of the magnetic head (5).

[Invention or problem to be solved]

However, in the magnetic head device as described above, the magnetic tape (
Perhaps attention has been focused solely on the rise of item 1), and development has proceeded.Recently, with the increase in the recording density of VTRs, the relative speed between the magnetic tape (1) and the magnetic head device has increased, and the magnetic head In order to improve the performance of the device, the magnetic tape (1) and the magnetic head (5) are designed to suppress the loss of effective magnetic flux due to the air gap between the magnetic tape and the magnetic head.
)(6) becomes larger and larger, and the contact pressure of the magnetic head (5) increases.
) (6) The gap depth, which is the length in the vertical direction from the sliding surface of the magnetic tape (1) attached to the gap (G), has become shorter. As a result, in the above-described head device, when used for a long time, the second magnetic head (6) always runs out of the gap before the first magnetic head (5), making it impossible to record or reproduce. It has arisen.

The present invention has been made to solve the above problems, and an object of the present invention is to obtain a magnetic head device that has high performance and high reliability even when used for a long time.

[Means to solve the problem]

The magnetic head device according to the present invention has the following advantages:
A pair of magnetic heads in which a closed magnetic circuit is configured and each having a core having a contact surface that contacts the magnetic tape are arranged in parallel in the magnetic tape running direction, and are positioned temporally after the running of the magnetic tape. The contact surface of the second magnetic head, which is located temporally before the running of the magnetic tape, with respect to the first magnetic head has increased wear resistance against sliding of the magnetic tape.

Further, in the magnetic head device according to another aspect of the present invention, the magnetic head has cores each forming a closed magnetic circuit through a gap having a gap depth extending in a direction perpendicular to the magnetic tape surface. When the magnetic tapes are arranged in parallel in the running direction, the gap depth of the second magnetic head that is located temporally after the magnetic tape travels with respect to the first magnetic head that is located temporally after the magnetic tape travels. It is something that has been deeply cultivated.

[Effect]

In a magnetic head configured in this way, the magnetic head and the magnetic tape slide, and the magnetic l\\rad position wears out, but the contact surface of the second magnetic head is smaller than the contact surface of the first magnetic head. Since the wear resistance of the magnetic head against the magnetic tape is high, the decrease in the gap depth of the second magnetic head is suppressed, and the life of the second magnetic head is extended, that is, the life of the second magnetic head is equal to that of the first magnetic head. It becomes the lifespan.

Further, in a magnetic head device of another invention, the first magnetic head and the second magnetic head are worn out by sliding the magnetic tape over the magnetic head, and the amount of wear is equal to that of the first magnetic head. Compared to the second magnetic head, there are more magnetic heads, but since the gap depth of the second magnetic head is larger, the time required for the gap depth to disappear can be longer, and the second magnetic head has a larger gap depth.
The life of the second magnetic head becomes the same as that of the first magnetic head.

〔Example〕

Examples of the present invention will be described below.

Embodiment 1 FIGS. 1(a) and 1(b) show a first embodiment of the present invention. In the figures, (5) is connected to the rotating body (3) (see FIG. For example, the contact surface on which the magnetic tape (1) slides (the long side of the sliding surface of the magnetic tape (1) has a length of 1 along the running direction (, b)).
．． 2[[1[1] This short side is the magnetic tape running direction (b
) and the head width (Ct 1 ) h
)0. A first magnetic head (6) having a diameter of 13 mm is disposed on the head head (7) in close proximity to and parallel to the first magnetic head (5), and is located temporally before the running of the magnetic tape (1). However, for example, this is a second magnetic head in which the long side of the sliding surface is 1.2 mm and the head width (Ct2) is 0.19n+m. Note that the gap depth (Gl) (G2), which is the length of the gap (10) (+1) between the magnetic heads (5) and (6) in the vertical direction from the sliding surface of the magnetic tape (1), is approximately 50 μm. It is.

In a magnetic head device configured in this way, for example in a VTR, the first magnetic head (5) is arranged as shown in FIG.
The magnetic head (6) is normally used for recording and reproduction.

Then, the magnetic head device slides on the magnetic tape (1), and the signal recorded by the first magnetic head (5) is transferred to the first magnetic head.
The magnetic head (5) reproduces data, and the second magnetic head (6) reproduces the data.
) will be reproduced by the second magnetic field (6). Then, due to the movement of the magnetic heads (5) (6) and the magnetic tape (1), the magnetic heads (5) (
The tip of 6) will gradually wear out.

In addition, in a magnetic head device in which two magnetic heads (5) and (6) are arranged in parallel in this way, as shown in FIG. Air flows into the contact surface and pushes up the magnetic tape (1), creating a minute gap between the magnetic tape (1) and the magnetic head (5). Therefore, the contact load of the first magnetic head (5) is lower than the contact load of the magnetic tape (1) and the second magnetic head (6). However, in the magnetic head device of the present invention, the head width (Ctl) of the first magnetic head (5) is larger than the head width (Ctl) of the second magnetic head (6).
) is formed to have a large head width (Ct2) so that the wear resistance of the contact surface of the first magnetic head (5) is greater than that of the contact surface of the second magnetic head (6). , the magnetic tape (1) of the first magnetic head (5) and the second magnetic head (6) against the sliding of the magnetic tape (1)
The amount of wear due to this is almost the same. In other words, the wear of the magnetic head depends on the contact pressure between the magnetic tape and the magnetic head.
By reducing this contact pressure, the amount of head wear can be reduced. However, simply reducing the contact load of this magnetic head device with respect to the magnetic tape (1) may result in deterioration of the head characteristics, or in general, in a VTR equipped with such a magnetic head device, the second magnetic head (6
) is used for normal recording, and the first magnetic head (5) is used for long-time recording, so the track width of the first magnetic head (5) is smaller than that of the second magnetic head (6). Because it is smaller, the first magnetic head (5) is smaller than the second magnetic head (6).
The recording conditions will become stricter. Therefore, the first magnetic head (
The wear resistance characteristics of the second magnetic head (6) must be improved without deteriorating the head characteristics of (5). This first
In the magnetic head device of the embodiment, the first magnetic head (5
), the head width (Ct2) of the second magnetic head (6)
By increasing the contact area between the second magnetic head (6) and the magnetic tape (1), the contact pressure of only the second magnetic head (6) is reduced, and the contact area between the second magnetic head (6) and the magnetic tape (1) is increased. ) has reduced head wear. Therefore,
A decrease in the gap depth (G2) of the second magnetic head (6) can be suppressed. By making the second magnetic head (6) wider than the first magnetic head (5) in this way, the gap depth (G2) of the second magnetic head (6) can be eliminated. The life of the second magnetic head (6) can be increased by the time of
As a result, the life of the VTR can be improved.

Furthermore, the inventor conducted a wear test using the first magnetic head (5) and the second magnetic head (6) formed with the same head width. In this wear test, the above magnetic head device was
Changes in the gap depth of the magnetic tape (1) were measured after the magnetic tape (1) was mounted on a TR and ran on a magnetic tape for 1000 hours. As a result, the gap depth (G2) of the second magnetic head
It was found that when compared with the gap depth (G1) of the first magnetic head, it decreases by about 1.5 times. Taking this into consideration, in the magnetic head device described above, the first
The head width (Ct2) of the second magnetic head is approximately 1.13 mm, while the width (Ctl) of the second magnetic head is 0.13 mm.
By increasing the distance by five times to 0°19 mm, the wear amount of the first magnetic head and the second magnetic head could be made almost the same.

Embodiment 2 FIG. 2 shows a second embodiment of the invention, in which:
(5) is, for example, the long side of the sliding surface or 1°2 mm, the head width (
Ct 1 ) h) 0. 15 mm, and the radius of curvature of the magnetic tape (1) on the contact surface (sliding surface) along the running direction is 10 m.
m first magnetic head, (6) is the long side of the sliding surface or 2r
nrn, the head width is 0.15 m + n, the radius of curvature of the sliding surface is 12 mm, and the radius of curvature of the first magnetic head (5) and the second magnetic head (6) is R1.
<R2, and the center of this radius of curvature is between the two gaps (9) of the magnetic head.
(10) is located on the center line between. Further, the dotted line in this drawing hypothetically shows the case where the radius of curvature of the second magnetic head (6) is made the same as the radius of curvature of the first magnetic head.

In the magnetic head device configured in this way, recording and reproduction are performed in the same manner as described in the first embodiment, and
Sliding between the magnetic heads (5) and (6) and the magnetic tape (1) causes wear on the sliding surface of the magnetic head, but the radius of curvature of the sliding surface of the first magnetic head (5) (R1
), the radius of curvature of the sliding surface of the second magnetic head (6) (
Since R2) is large, a decrease in the gap depth (G2) of the second magnetic head can be suppressed. That is, the inventor conducted the above-described wear test and investigated the relationship between the wear of the magnetic head and the radius of curvature, and the results are shown in FIG. From this figure, it can be seen that as the radius of curvature of the sliding surface of the magnetic head increases, wear of the magnetic head can be suppressed.

The reason for the stiffness is that as the radius of curvature increases, the contact area between the sliding surface of the magnetic tape (1) and the magnetic head increases, so the contact pressure of the magnetic tape decreases and wear on the magnetic head is suppressed. In the magnetic head device configured in this way, the life of the second magnetic head (6) can be improved to the same level as that of the first magnetic head (5). can extend the life of the VTR.

Furthermore, when the inventor conducted the above-mentioned wear test, it was found that in the magnetic head device of this second embodiment, the wear of the first magnetic head (5) and the second magnetic head (6) was almost the same. became.

In addition, in this second embodiment, the radius of curvature of the sliding surface of the magnetic head in the running direction of the magnetic tape (1) has been described, but the radius of curvature of the sliding surface of the magnetic head in the direction perpendicular to the running direction of the magnetic tape (1) has been described. It goes without saying that the wear characteristics of the magnetic head can also be changed by changing the radius of curvature of the magnetic head.

Example 3 FIG. 4 shows a third example.
In this embodiment, the first magnetic head (5) and the second magnetic head (6) have the same shape except for the gap length.

The first magnetic head (5) and the second magnetic head (6) are connected to the rotating body (3) via the head base (7).
The magnetic head (5) (see Fig. 9) is attached to the magnetic head (5) (see Fig. 9) and protrudes from the head window (3a) provided in the rotating body (3).
6), the protrusion amount (Hl) of the first magnetic head (5) and the protrusion amount (Hl) of the second magnetic head (6) are in the relationship Hl>Hl. It is something.

Also in the magnetic head device configured in this way, the magnetic heads (5) and (6) are moved by the sliding of the magnetic tape (1).
However, in this magnetic head device, the amount of protrusion (Hl) of the first magnetic head (5)
Since the second magnetic head (6) is mounted on the head base (7) in such a manner that the amount of protrusion (Hl) of the second magnetic head (6) is smaller than that of a conventional magnetic head device, the second magnetic head (6) The wear amount of the first magnetic head (5) and the second magnetic head (6) can be reduced, and the wear amount of the first magnetic head (5) and the second magnetic head (6) are almost the same.

That is, FIG. 5 shows the relationship between the amount of protrusion (H) of the magnetic head and the amount of head wear. The smaller the head protrusion (H), the
The amount of wear can be kept small. This is the magnetic head (5)
Since the contact load between (6) and the magnetic tape (1) is smaller, as a result of the above-described wear test, the protrusion amount of the second magnetic head is approximately 2 μm compared to the first magnetic head (5).
By making the size small, the amount of wear of the first magnetic head (5) and the second magnetic head (6) becomes almost the same. In addition, in such a magnetic head, since the second magnetic head (6) is used for normal recording and the first magnetic head (5) is used for long-time recording, the first magnetic head (5) is The track width is smaller than that of the second magnetic head (6), and the track width of the first magnetic head (5) is smaller than that of the second magnetic head (6).
) recording conditions become stricter. However, in the magnetic head device of this embodiment, since the contact pressure does not decrease in the first magnetic head (5), the life of the second magnetic head (6) can be extended without deteriorating the head performance. I can figure it out.

Furthermore, with this method, the wear resistance characteristics of the first magnetic head and the second magnetic head can be changed without changing the manufacturing method of the magnetic head from the conventional method.

Embodiment 4 FIG. 6 shows a fourth embodiment of the present invention, in which the shapes of the first magnetic head (5) and the second magnetic head (6) are the same except for the gap length. First magnetic head (5
) and the core (12) (13) of the second magnetic head (6)
), which is a magnetic material such as ferrite, has a Vickers hardness of the first magnetic head (5) and the second magnetic head (6).
), the Vickers hardness (Bl) of the first magnetic head (5)<Vickers hardness (B2) of the second magnetic head
This is the relationship between

In the magnetic head device configured in this way, the second
The Tockers hardness (B2) of the magnetic head (6) is the first
Since the Vickers hardness (B1) is higher than the Vickers hardness (B1) of the second magnetic head (5), the wear resistance against sliding of the magnetic tape (1) is good, so the decrease in the gap depth in the second magnetic head is suppressed. . Further, as in the first to third embodiments described above, the durability of the second magnetic head (6) can be improved by changing the Vickers hardness of the ferrite constituting the magnetic head without changing the shape of the magnetic head. Since the wear characteristics can be improved, conventional magnetic tape (1
) and the sliding relationship of the magnetic head device, there is no change in head performance and the life of the VTR can be extended.

Embodiment 5 FIG. 7(a) shows a fifth embodiment of the present invention. In this embodiment, the length of the core constituting the magnetic head along the magnetic tape running direction is defined as It. Then, the first
In the magnetic head (5) and the second magnetic head (6), the relationship is as follows: ■ Core length (Itl) of the first magnetic head < I-core length (It2) of the second magnetic head. It is something. Further, the radius of curvature of the magnetic heads (5) and (6) is on the center line between the gaps (10) (o), and
Both have a radius of curvature of 10 mm, and a gap depth (Gl)
(G2) is 50 μm.

Even in the magnetic head device configured in this manner, when the magnetic tape slides on the magnetic head device, the magnetic head is worn out. Then, the length of the I core (11) of the first magnetic head (5) is the length of the echo core of the second magnetic head (11).
(2) Since the structure is larger, the wear resistance of the second magnetic head against the magnetic tape (1) is increased.
Since the wear of the gap depth (G2) of the second magnetic head is reduced, the life of the second magnetic head (6) is extended. In other words, as shown in FIG. 7(b), the length of one core (I tl) of the first magnetic head and the I of the second magnetic head are
The core length (It2) is in the relationship Itl<It2, and the curvatures of the magnetic tape sliding surfaces of the first magnetic head (5) and the second magnetic head (6) are on the same radius of curvature. Therefore, the contact (B) of the sliding surface of the second magnetic head (5) in the magnetic tape running direction is the same as the contact (A) of the second magnetic head (6).
) can be made larger. Therefore, the contact area of the second magnetic head (6) can be increased, and the contact area of the second magnetic head (6) can be increased.
Since wear of the second magnetic head (6) is suppressed,
The lifespan of the magnetic head device can be extended, and the lifespan of the magnetic head device can be extended.

Further, in the embodiment described above, the first magnetic head (5)
This describes a modification of the configuration or structure of the second magnetic head (5) in order to further improve the abrasion resistance characteristics of the second magnetic head (6) against the magnetic tape, and the method described above is used in combination. It goes without saying that there is no problem even if the wear resistance of the second magnetic head (6) against sliding of the magnetic tape is improved.

Embodiment 6 FIG. 8 shows a sixth embodiment of the present invention, in which the magnetic heads (5) and (6) are made of ferrite having the same Vickers hardness, and the magnetic tape (1) in the gap between the magnetic heads is made of ferrite. ) surface, the gap depth (G1) of the first magnetic head (5) and the gap depth of the second magnetic head (6) (G2) has a relationship of Gl<02, specifically, the gap depth (G1) of the first magnetic head (5) is 20 μm, and the gap depth (G1) of the second magnetic head (6) is 20 μm.
2) is 30 μm.

The magnetic head device configured in this manner also slides on the magnetic tape (1) to perform recording or reproduction, as described above. Then, due to sliding with the magnetic tape (1), wear occurs on the sliding surface of the magnetic head, and the gap depth (G) of the magnetic head decreases. Then, the gap depth (G) of the first magnetic head (5) and the second magnetic head (6) is no longer approximately the same.

In other words, since the head wear amount of the first magnetic head (5) is smaller than that of the second magnetic head (6), the gap depth of the first magnetic head (5) is lower than that of the second magnetic head (6).
), the first magnetic head (5) and the second magnetic head (6) will not have substantially the same gap depth.

In addition, the first magnetic head (5
) is used for long-time recording and the second magnetic head (6) is used for normal recording, so the track width of the first magnetic head (5) is smaller than the track width of the second magnetic head. Ru. Therefore, the first magnetic head (5)
The recording conditions are stricter than that of the magnetic head (6). However, in this magnetic head device, the first magnetic head is Since the life of the second magnetic head can be extended without changing the gap depth (5), the life of the VTR can be extended without deteriorating the performance of the magnetic head device.

〔Effect of the invention〕

According to the present invention, the contact surface of the second magnetic head is configured to have greater wear resistance against the magnetic tape than the contact surface of the first magnetic head, so that the performance of the magnetic head device is not reduced. The wear of the second magnetic head is suppressed,
The decrease in the gap depth of the second magnetic head can be suppressed, and the life of the present invention can be extended. As a result, it is possible to obtain a magnetic head with high performance and high reliability over a long period of time.

Further, in another aspect of the present invention, since the gap depth of the second magnetic head is formed larger than that of the first magnetic head, the life of the second magnetic head can be extended. can. As a result, it is possible to obtain a magnetic head with high performance and high reliability over a long period of time.

[Brief explanation of the drawing]

FIG. 1(a) is a top view of a magnetic head device according to a first embodiment of the present invention, and FIG. 1(b) is a cross-sectional view of the magnetic head device of FIG. 1(a) taken along line I-I. FIG. 2 is a partial sectional view of a magnetic head device according to a second embodiment, FIG. 3 is a diagram showing the relationship between the radius of curvature of the magnetic head device and the amount of wear on the head, and FIG. 4 is a diagram showing a third embodiment of the present invention. 5th partial cross-sectional view of the magnetic head device of
6(a) is a top view of the magnetic head device of the fourth embodiment of the present invention, and FIG. 6(b) is a diagram showing the head width and head wear amount of the magnetic head device. 7(a) is a sectional view of the magnetic head device according to the fifth embodiment of the present invention, and FIG. 7(b) is a sectional view taken along the line Vl--Vl of the magnetic head device of FIG. Fig. 8 is a diagram for explaining the sliding relationship with the magnetic tape in the magnetic head device of a), Fig. 8 is a diagram showing a magnetic head device according to the sixth embodiment of the present invention, and Fig. 9 is a diagram showing a general case of a VTR. A layout diagram of a magnetic head device, FIG. 10 is a configuration diagram of a conventional magnetic head device, FIG. 11 is a diagram for explaining the relationship between a conventional magnetic head device and a magnetic tape, and FIG. 12 is a diagram of a conventional magnetic head device FIG. In the figure, (1) is a magnetic tape, (5) is a first magnetic head device, (6) is a second magnetic head device, (1,0
) (11) is a gap. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (2)

[Claims] (1) A first magnetic head, which has a core in which a closed magnetic circuit is formed through the gap and has a contact surface that comes into contact with the magnetic tape, and is positioned temporally after the running of the magnetic tape; A closed magnetic circuit is formed through the first magnetic head, and the core has a contact surface that contacts the magnetic tape and has greater wear resistance than the contact surface of the first magnetic head. A magnetic head device comprising: a second magnetic head arranged in parallel with the head in the magnetic tape running direction and located temporally before the magnetic tape running. (2) A first magnetic core having a core in which a closed magnetic circuit is formed through a gap having a gap depth extending in a direction perpendicular to the magnetic tape surface, and located temporally after the running of the magnetic tape. a head, having a core in which a closed magnetic circuit is formed through a gap having a gap depth deeper than the gap depth in the first magnetic head, and arranged in parallel with the first magnetic head in the running direction of the magnetic tape; and a second magnetic head located temporally before the running of the magnetic tape.