JPH03273516A - Multichannel magnetic head - Google Patents

Abstract

PURPOSE:To optimize the contact of respective magnetic heads with a magnetic tape by providing >= 3 pieces of head chips on a single head base and specifying the radius of curvature of the curve connecting the respective gap parts of the head chips. CONSTITUTION:The one head base 5 is disposed thereupon with >=3 pieces of the heads. The line 1 connecting the peaks in the sliding direction of the magnetic head chips 4 is expressed as the shape in the sliding direction over the entire part of the magnetic head and the value thereof is set at the radius of curvature in the sliding direction of >= 90% of the radius 3 of the cylinder to be used. The contact pressures acting on the magnetic tape are, therefore, respectively maintained at the same level even if the plural magnetic head chips 4 are disposed on the one head base 5. The optimum contact of the multichannel magnetic heads with the magnetic tape is assured in this way and the good recording and reproducing are possible. The wear of >= 3 pieces of the heads is evened.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a multichannel magnetic head used in high-definition video tape recorders (hereinafter abbreviated as VTR) and the like.

2. Description of the Related Art In a conventional VTR, a magnetic head is fixed so as to protrude by a predetermined amount from a cylinder (here, the radius of the cylinder is 31111 m) around which a magnetic tape is wound at a certain angle. The conventional magnetic head mentioned above will be explained below with reference to the drawings. FIG. 7 shows the structure of a conventional magnetic head. The shape of the head chip 4 mounted on one head base 5 is as follows.
The radius of curvature in the sliding direction centering on head gap 2 is 9■~1
1- is used. Regarding the number of head chips, up to two heads can be mounted on one head base, and the shape of the head chips has a radius of curvature in the sliding direction around the head gap of 9 to 11. things are used. However, recent VTR systems are becoming increasingly high-quality and compact, and are required to record broadband signals with a high signal-to-noise ratio and high density. Therefore, it is necessary to arrange and mount a plurality of head chips in the horizontal direction on one head base. The shape of the magnetic head is inevitably long in the sliding direction.

Problems to be Solved by the Invention However, as shown in FIG. 8, in a shape in which the radius of curvature 8 of the circle connecting the head gap 2 is significantly smaller than the cylinder diameter, it is difficult to connect multiple heads on one head base. All will not make good contact with the tape. In other words,
In the current multi-head, as shown in FIG. good contact can be obtained only with the two
For the chips 14 and 17 on both sides, contact is obtained only on the outside of the center of the chip. Incidentally, FIG. 8a shows a schematic side view of the cylinder 9, and FIG. 8a shows a schematic top surface of the head portion.

That is, in Fig. 8, when a cylinder diameter of φ62 is used, the radius of curvature connecting the vertices of the four magnetic head tips in the sliding direction is 16.41 nm, the magnetic head gap is 1000 μm between adjacent heads, and the magnetic field is 400 μm between head chips. Each hent tip 10, 11 . when the magnetic tape is run in the head. 12゜13 are tape input υ side, input!
The sliding traces of the head chips 10, 11, 12, and 13 on the ll side center, exit side center, and exit side head bases are 14.15 and 16.17 in FIG. 8a, respectively. At sliding mark 16°16, it was observed that both the tape entry and exit sides were in symmetrical contact with head gap 2 as the center, but sliding mark 1
In No. 4, when looking at the head gap 2, there is contact from the chip end on the tape entry side to the gap 2, but no contact is observed on the exit side.

In the sliding trace 15, when viewed centering around the head gap 2, contrary to the sliding trace 14, there is contact from the chip end on the tape exit side to the gap 2, but no contact is observed on the tape entrance side. In addition, when measuring the envelope, head chips 15 and 16 have good contact and a normal rectangular shape as shown in Figure 2a, but head chips 14 and 17 have an envelope shape as shown in Figure 2. However, I could only get the desired result.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a multi-channel magnetic head that can address this problem, bring the tape into contact with the gaps of all the heads, and equalize the head depth.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention uses a multi-head shape in which three or more heads are arranged on one head base. In addition, for the two outer head chips on one head base, the angle at which the line extending along the abutting surface of the gap intersects is 20 degrees or less, and the head chip The distance between the gaps is set to be larger than 1.6 times the length in the sliding direction of nine adjacent head chips.

Effects of the Invention According to the above-described configuration, the present invention can maintain the same contact pressure exerted by the magnetic tape on each head chip even if a plurality of magnetic head chips are arranged on one head base, and can provide multi-channel communication. The magnetic head makes optimal contact with the magnetic tape, allowing good recording and reproduction, and three or more heads wear out evenly.

EXAMPLE Hereinafter, a multi-channel magnetic head according to an example of the present invention will be described with reference to the drawings. FIG. 1 shows the configuration of the magnetic head of this embodiment. Here, magnetic head chips with a radius of curvature in the sliding direction of 9111!1 or more, a radius of curvature in the width direction of 21M1 or less, and a core width of 200 μm or less are used. A line 1 connecting the vertices in the moving direction is expressed as the shape of the entire magnetic head in the sliding direction, and its value is taken as the radius of curvature in the sliding direction of 90 inches or more of the cylinder radius 3 used. In addition, the two outer heads of the plurality of head tips 4 on one head base 5 are both tilted outward so that the radius of curvature on the gap 2 does not change, and the plurality of hent tips 4 on one hendo base 6 are tilted outward. As shown in FIG. 3, if the angle 6 at which the extension lines of the positions of the head gaps 2 on both sides intersect is varied as shown in FIG. If you set it so that it is below 90%, you can obtain an envelope of 90% or more. As a result, wear of both outer head tips occurs mainly around the hent tips, and uneven wear can be suppressed. In addition, in Figure 4, from the relationship between the head shape on one head base and the flatness of the envelope, if the head shape is 90 inches or more of the cylinder diameter, the flatness of the envelope will be 90 degrees.
% or more.

In addition, a magnetic head is installed such that the difference in the amount of protrusion of the cylinders 9 on all the plurality of head chip gaffs ``2'' on one head base 5 is within 10%, and As shown in the figure, there is approximately 400 a between the plurality of head chips 4 on one henode base 6.
When a magnetic tape is run with a gap of m, even if the magnetic head is long in the sliding direction, the magnetic tape winds into the gap and the magnetic tape 18 is placed in the center of one head chip 4.
optimal contact is always obtained. By providing a gap 2 at the optimum contact portion, higher output can be obtained for all magnetic heads than in the conventional multi-head. Furthermore, since the contact between each head chip 4 is the same, wear becomes uniform and the life of the head is extended. 7) As shown in FIG. 6, the ratio of the sliding direction length of one head chip on one head base to the gap distance between adjacent head chips is:
When the ratio exceeds 1.6, the crosstalk from the adjacent head decreases rapidly, and the amount of crosstalk at that time is reduced to a ratio of 1.
It was found for the first time through experiments that the head chip spacing can be reduced to about 1/3 of that without the head chip spacing, which is a value that poses no problem in practice.

In this embodiment, among the plurality of head chips,
The distance between the gaps between adjacent head chips may be set to be larger than the center on the head base, rather than closer to the outside on both sides.

Furthermore, it goes without saying that the lengths in the sliding direction of the head chips among the plurality of head chips may be set to different values on the head base.

Effects of the Invention As described above, even when a plurality of magnetic heads are installed on one head base, the present invention is capable of making optimal contact with the magnetic tape over the gap between each magnetic head. This configuration enables extremely stable recording and playback.

[Brief explanation of drawings]

FIG. 1 is a structural diagram of a multi-channel magnetic head according to an embodiment of the present invention. FIGS. 2 a and 2 b are waveform diagrams of envelope 1 of the head located at the center ffl on one head base, and envelopes of the two outer heads. Figure 3 is a characteristic diagram showing the relationship between the angle at which lines extending along the abutting surfaces of the two outermost head ganops of the multi-head chip intersect and the flatness of the envelope, and Figure 4 is a characteristic diagram showing the relationship between the flatness of the envelope and the cylinder diameter. A characteristic diagram showing the relationship between the ratio of the multi-head diameter and the flatness of the envelope, and Figure 6 shows the contact state between the head and the tape when the overall shape of the magnetic head on one head base is cylindrical. The schematic diagram, Figure 6, shows the contact state between the head and the tape when the ratio of the length of one head chip in the sliding direction to the gap distance between adjacent head chips is 1/3 of the cylinder diameter. FIG. 1...Line connecting the vertices in the sliding direction, 2...
・Head gap, 3... Cylinder radius used,
4...Head chip, 6...Head base, 6...Angle where extension lines intersect, 18...
····Magnetic tape.

Claims (10)

[Claims] (1) A magnetic head placed on a rotating cylinder, where N is an integer of 3 or more, and N is placed on a single head base.
The radius of curvature of a curved line connecting the gap portions of the N head chips in an arc shape in a plane substantially perpendicular to the rotation axis of the rotary cylinder is the curvature radius of the rotary cylinder. A multichannel magnetic head characterized in that the value is 90% or more of the radius. (2) Among the N head chips, lines extending from the gap portions of the two outer head chips toward the rotation center of the rotating cylinder along the abutting surfaces of the two gaps intersect. 2. The multichannel magnetic head according to claim 1, wherein the angle is set to be 20 degrees or less. (3) The shape of the N head chips is such that each has a radius of curvature in the sliding direction of 9 mm or more, each has a radius of curvature in the width direction of 2 mm or less, and each has a core width of 200 μm or less. Claim 1 characterized in that
The described multichannel magnetic head. (4) Among the N head chips, the distance between adjacent head chips is set to be larger as the distance between adjacent head chips approaches both outer sides from the middle on the head base. Channel magnetic head. (5) The distance between the gaps between adjacent head chips among the N head chips is set to be larger than 1.5 times the sliding direction of the adjacent head chips. The described multichannel magnetic head. (6) The multi-channel magnetic head according to claim 1, wherein lengths in the sliding direction of the head chips among the N head chips are set to different values on the head base. (7) The sliding direction length of each head chip among the N head chips is set so that the contact pressure of the magnetic tape against each head chip is approximately the same. multi-channel magnetic head. (8) Among the N head chips, the lengths of the head chips in the sliding direction are set so that the amount of wear in the gap portion of each head chip due to contact with the magnetic tape is approximately the same. 7. The multi-channel magnetic head according to claim 6. (9) The sliding direction length of the head chip among the N head chips is set to a smaller value as it approaches both outer sides from the middle on the head base. Multichannel magnetic head. (10) The sliding direction length of the head chip among the N head chips is set to a larger value as it approaches both outer sides from the middle on the head base. Multichannel magnetic head.