JPH03189907A - Magnetic head and its production - Google Patents

Abstract

PURPOSE:To bring a magnetic tape into adequate contact with the top of a head gap by forming a head notch longer in the rear part thereof in a traveling direction. CONSTITUTION:The center of zero order interference fringes shifts successively backward in the sliding direction with respect to the head gap 1 with an increase in the relative speed of the head/tape when recording and reproducing are executed. The track grooves are so worked that the track groove depth X corresponding to the forward side in the sliding direction and the track depth Y on the rear side are not X=Y like heretofore but are longer in the track groove depth X than Y. The surfaces where ferrite blocks A, B are respectively stuck to each other, i.e. joint surfaces 23 are where the head gap 1 is formed. The position of the head gap 1 with respect to the head notch is changed if the grooves are worked in such a manner. The stable recording and reproducing are possible in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a magnetic head used in high-speed rotation video tape recorders and the like, and a method for manufacturing the same.

In a conventional video tape recorder, a magnetic head is fixed so as to protrude by a predetermined amount from a cylinder around which magnetic tape is wound at a predetermined angle.

A conventional magnetic head will be explained using FIGS. 2 and 3. FIGS. 2(a) to 2(a) schematically show the head manufacturing method. As shown in FIG. 2(b), when a magnetic material block is machined with track grooves and a notch 22 is formed, the notch 22 is enlarged. The track groove depth x in the sliding direction with respect to the head gap (joint surface) as shown in the figure.
, y (head notch part) was constructed so that the front and rear sides had the same depth. Also, Figure 3(a)
As shown in (g)), the shape of the magnetic head is normally VH3
In this case, the shape R in the sliding direction is 9.0 to 11.0 mm, and the core thickness direction r is about 2 mm. In this magnetic head, the lengths L1 and L2 of the head notch 2 are made equal with respect to the head gap 1. By this method,
When recording and reproducing are performed while the position of the magnetic head relative to the rotating cylinder is fixed, the relative speed between the magnetic head and the magnetic tape increases in proportion to the speed, as shown in Figure 4.Theoretical curve 41, based on experimental results. It was found from the obtained curve 42 that the output was significantly reduced. This phenomenon occurs when the relative velocity is 5.8 m/sec as shown in Figure 5.
. The center of the zero-order interference fringe is shown as 51 elliptical fringes on the magnetic head gap 1. However, the relative speed is 1
As it becomes larger, such as 1.6 m/sec and 3 times as high as 17°4 m/sec, the center of the zero-order interference fringe tends to shift backward in the sliding direction to 52.53 with respect to head gap 1. It was found that the output was reduced due to this.

Problems to be Solved by the Invention As mentioned above, when recording and reproducing are performed while the position of the magnetic head relative to the rotating cylinder is fixed, as the relative speed of the head/tape increases, the contact position between the magnetic head and the magnetic tape shifts. There was a problem in that the position of the head gap of the magnetic head deviated from the optimal contact position.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention provides a magnetic head that allows the magnetic head of the present invention to
The configuration was such that the zero-order interference fringe was always located on the head gap. By lengthening the rear portion of the head notch in the running direction, the magnetic tape is configured to optimally come into contact with the head gap.

Effect of the present invention The above-described structure allows the position of the magnetic head gap to always be at an optimal position even when the relative speed between the magnetic head and the magnetic tape increases, and the contact state between the tape and the head can be maintained in a stable state. Therefore, good recording and playback becomes possible.

Embodiment Hereinafter, a magnetic head device according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 and FIG. 2 each show the overall configuration of the present invention. Figure 1(a)
shows the structure of the magnetic head.

(b) is a top view of the head. The head gap (FIG. 1) is located on the rear side of the center of the head notch (FIG. 1) in the sliding direction. Here, as shown in FIG. 5, when the relative velocity is 5.8 m/sec, the center of the zero-order interference fringe is shown as 51 elliptical fringes on the magnetic head gap 1. However, the relative speed is 11.6 m/s, which is twice as high.
ec, and as it increases to 17.4 m/sec, which is 3 times larger, the center of the 0th order interference fringe tends to shift backward in the sliding direction to 52.53 with respect to the head gap 1, so the output decreases. I know what you're doing.

That is, the length ratio Ll/L2 of the length from the center of the shape R in the sliding direction to the magnetic head gap and the length L2 from the magnetic head gap to the rear end in the sliding direction is 0.
．． Set it to 2-1.0. Here, the head notch 2 is an area where the track grooves formed during head manufacturing are filled with glass formed by melting lead-based glass, etc., and various shapes can be created by changing the track groove depth. Can be manufactured.

When a current is passed through the coil 4 in FIG. 1, a magnetic field is generated in the core 6, and the leakage magnetic field generated in the gap 1 causes recording on the magnetic tape. Moreover, FIG. 2(a) shows a ferrite block in which winding grooves are formed. A is a front block in the tape sliding direction, and B is a rear block. (b) shows the shape of the block 21 after the track grooves 22 have been processed.

As shown in Figure 5, as the relative velocity increases, 0
The center of the next interference fringe shifts backward in the sliding direction with respect to the head gap 1. Here, an enlarged view of the notch part of the ferrite block from the Z direction is shown in Figure 2 (8).
), Ql). (Unlike the conventional station, the track groove depth X on the front side in the sliding direction and the track groove depth Y on the rear side are not X = Y, but as shown in (h), the track groove depth is For example, the depth of the track groove is made to be Y/X-'1/3 to 2/3.Also, the surface to which each ferrite block ASB is bonded, that is, the bonding surface 23 becomes the magnetic head gap 24. By processing in this way, the position of the head gap 1 relative to the head notch can be changed. Therefore, as shown in FIG. 1, LL/L2 = 0.
2 to 1.0, an optimal magnetic head can be obtained.

Effects of the Invention As described above, in the present invention, the contact position between the magnetic head and the magnetic tape shifts due to a change in the relative speed between the rotating magnetic head and the magnetic tape. Therefore, by lengthening the rear portion of the head notch in the running direction, the position of the head gap is optimized, which has the effect of making extremely stable recording and reproduction possible.

[Brief explanation of drawings]

FIG. 1 shows the structure of a video head in an embodiment of the present invention, (a) is a configuration diagram of the head of the present invention, (b) is a configuration diagram of a sliding surface, and FIG. 2 is a configuration diagram of the head of the present invention and the conventional head. The manufacturing process diagram, Figure 3, shows the structure of a conventional video head, (a
) is a conventional head configuration diagram, and (b) is a state diagram showing the contact area of the sliding interference fringe with the head gap. (Glass), 3... Joint surface, 4...
...Coil, 5...Head width, 6...
Core, LL... Length from the center of shape R in the sliding direction to the magnetic head gap, L2... From the magnetic head gap to the end of the magnetic head notch on the rear side in the sliding direction Length, 21...Core material, 22...
...Track groove depth, 23...Joint surface, 2
4...Window, X...Track groove depth on the front side in the sliding direction, Y...Track groove depth on the rear side in the sliding direction, 41... ...Theoretical relative speed and output characteristics, 42...Actual relative speed and output characteristics, 51...5.8 m/sec 0
0th-order interference fringe, 52- . . . 0th-order interference fringe at 11.6 m/sec, 53... 0th-order interference fringe at 17.4 m/sec.

Claims (3)

[Claims] (1) A head gap is provided from the center of the arcuate shape R in the sliding direction of the magnetic head to the rear side in the sliding direction,
A magnetic head characterized in that the length of the core on the front side in the sliding direction is longer than the length of the core on the rear side in the sliding direction. (2) The ratio of the length from the center of shape R in the sliding direction to the magnetic head gap to the length from the magnetic head gap to the end of the magnetic head notch on the rear side in the sliding direction is 0.25 to 1.
2. The magnetic head according to claim 1, wherein the magnetic head is 0. (3) A method for manufacturing a magnetic head, in which the track grooves are machined in a material block of the magnetic head, and the depth of the grooves is made shallow in the core on the rear side in the sliding direction, and deep in the core on the front side in the sliding direction.