JP2502772B2 - Magnetic head and manufacturing method thereof - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic head used in a video tape recorder for high speed rotation and a method for manufacturing the magnetic head.

2. Description of the Related Art In a video tape recorder, a magnetic head is fixed so as to protrude from a cylinder around which a magnetic tape is wound at a predetermined angle by a predetermined amount. A conventional magnetic head will be described with reference to FIGS. 2 and 3. 2A to 2G show the outline of the method for manufacturing the head. As shown in FIG. 7B, when a magnetic material block is processed into track grooves to form a notch 22, an enlarged view thereof is shown in FIG. The track groove depths X and Y (the head notch portion) of (1) were configured such that the front side and the rear side had the same depth. Further, as shown in FIGS. 3 (a) and 3 (b), 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 the normal VHS. In this magnetic head, the head notches 2 on the front side and the rear side in the tape sliding direction are formed to have the same length centering on the head gap 1. By this method
When recording / reproducing is performed with the position of the magnetic head with respect to the rotating cylinder fixed, the relative speed between the magnetic head and the magnetic tape rises in proportion to the speed, as shown in FIG. It was found from the obtained curve 42 that the output was significantly reduced. This phenomenon is shown as 51 elliptical stripes on the magnetic head gap 1 at the center of the zero-order interference fringe when the relative velocity is 5.8 m / sec as shown in FIG. However, as the relative velocity doubled to 11.6 m / sec and tripled to 17.4 m / sec, the centers of the 0th order interference fringes were shifted to the head gap 1 by 52 and 53, respectively, and backward in the sliding direction. It was found that the output decreased because there was a tendency to go.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention As described above, when recording / reproducing is performed while the position of the magnetic head with respect to the rotary cylinder is fixed, the contact position between the magnetic head and the magnetic tape shifts as the relative speed of the head / tape increases. The problem is that the position of the head gap of the magnetic head deviates from the optimum contact position.

Means for Solving the Problems In order to solve the above problems, the magnetic head of the present invention has a length L1 from the center of the shape of the magnetic head in the tape sliding direction to the magnetic head gap, and a magnetic head gap to the tape. The feature is that L1 / L2, which is the ratio to the length L2 to the end of the magnetic head notch on the rear side in the sliding direction, is set to 0.25 to 1.0.

Further, in the magnetic head manufacturing method of the present invention, in the processing of the track groove of the material block of the magnetic head, the depth of the groove is shallow in the core on the rear side in the sliding direction and deep in the core on the front side. It is a feature.

Action The present invention makes it possible to keep the contact state between the tape and the head in a stable state because the position of the magnetic head gap is always the optimum position even if the relative speed between the magnetic head and the magnetic tape increases due to the above configuration. In addition, good recording and reproduction can be performed.

Embodiment A magnetic head device according to an embodiment of the present invention will be described below with reference to the drawings. 1 and 2 each show the overall configuration of the present invention. FIG. 1 (a) shows the structure of the magnetic head. (B) is the figure which looked at the head from the upper surface. The head gap 1 is on the rear side in the sliding direction with respect to the center of the head notch 2. 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 double 1
As the center of 0th-order interference fringes tends to shift backward 52 and 53 with respect to the head gap 1 as the size increases to 1.6m / sec and tripled to 17.4m / sec, the output is increased. I know it's falling. That is,
The length ratio L1 from the center of the shape R in the sliding direction to the magnetic head gap to the length L2 from the magnetic head gap to the rear end in the sliding direction is L1 / L2 = 0.25 to 1.0. Here, the head notch 2 is a region where the lead grooved glass or the like is melted to fill the track groove processed at the time of manufacturing the head and is filled with the glass, and has various shapes 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 magnetic tape is recorded by the leakage magnetic field generated in the gap 1. Further, FIG. 2 (a) shows a ferrite block having winding grooves formed therein. A is a front block in the tape sliding direction, and B is a rear block. FIG. 3B shows a shape in which the track groove 22 of the block 21 has been processed.

As the relative velocity increases, as shown in Fig. 5,
The center of the 0th-order interference fringe shifts backward with respect to the head gap 1 in the sliding direction. Here, the ferrite block is shown by enlarging the notch portion from the Z direction in FIGS. 2 (g) and 2 (h). The track groove depth X on the front side in the sliding direction and the track groove depth Y on the rear side as in the case of (g) are not X = Y but X as shown in (h).
Processing is performed so that the depth of the Y track groove is longer than that of Y.
For example, the track groove depth is set so that Y / X = 1/3 to 2/3. The surface where the ferrite blocks A and B are bonded together, that is, the joint surface 23 is where the magnetic head gap 24 is formed. With such processing, the position of the head gap 1 with respect to the head notch can be changed.
Therefore, as shown in FIG. 1, an optimum magnetic head can be obtained with L1 / L2 = 0.25 to 1.0.

As described above, according to the present invention, the contact position between the magnetic head and the magnetic tape is displaced due to the change in the relative speed between the rotary magnetic head and the magnetic tape. Therefore, the head notch and the rear portion in the traveling direction are lengthened so that the position of the head gap is set to the optimum position, and there is an effect that extremely stable recording / reproducing can be performed.

[Brief description of drawings]

FIG. 1 shows the structure of a video head according to an embodiment of the present invention. (A) is a block diagram of the head of the present invention, (b) is a block diagram of a sliding surface, and FIG. 2 is a head of the present invention and a conventional head. Fig. 3 shows the structure of the conventional video head.
(A) is a conventional head configuration diagram, (b) is a configuration diagram of a sliding surface, and FIG. 4 is a characteristic diagram of output by relative speed. Fifth
The figure is a state diagram showing the contact area of the 0th-order interference fringes with various relative velocities with the head gap. 1 ... Head gap, 2 ... Head notch (glass), 3 ... Bonding surface, 4 ... Coil, 5 ... Head width,
6 ... Core, L1 ... Length from center of shape R in sliding direction to magnetic head gap, L2 ... Length from magnetic head gap to rear end of magnetic head notch in sliding direction, 21 …… Core material, 22 …… Track groove depth, 23 …… Joint surface, 24 …… Window, X …… Track groove depth that is the front side in the sliding direction, Y …… Track groove depth that is the rear side in the sliding direction 41 ... theoretical relative speed and output characteristics, 42 ... actual relative speed and output characteristics, 51 ... 5.8m / sec 0th order interference fringes, 52 ... 11.6m / sec 0th order Interference fringe, 53 …… 17.4 m / sec 0th order fringe.

Claims (2)

(57) [Claims] 1. A length L1 from the center of the shape of the magnetic head in the tape sliding direction to the magnetic head gap, and a length L2 from the magnetic head gap to the rear end of the magnetic head notch in the tape sliding direction. The ratio of L1 / L2 is 0.25 to 1.0
A magnetic head characterized by the following. 2. A method of manufacturing a magnetic head, characterized in that, in processing a track groove of a material block of a magnetic head, the groove depth is shallow in a core on the rear side in the sliding direction and deep in the core on the front side. Method.