JPH0585965B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a magnetic head, and in particular to a video magnetic head that is designed to prevent the space between the magnetic tape and the magnetic head gap from becoming large in order to achieve short wavelength recording. Regarding.

[Prior Art] As shown in the perspective view of FIG. 8, a conventional magnetic head of this type has a ferrite block 1 as a base, the portion defining the track width of the recording gap 4 is made of a magnetic alloy 2, and the edge of the magnetic head is made of a magnetic alloy 2. It had a structure in which parts were protected with glass 3. 5 is a back gap, and 6 is a winding window. When observed from the arrow direction 7 in FIG. 8, the width of the magnetic alloy 2 is equal over its entire length, as shown in FIG. ，
9 were parallel.

[Problems to be Solved by the Invention] When the head with the structure shown in FIG. 9A is run in contact with the tape for a long time, the alloy portion 2, which has a relatively low hardness and is easily worn, becomes concave, as shown in FIG. 9B. , arrow 1
If you run the magnetic tape in the direction of 0, arrow 11
Air is sucked in the direction of the gap 4, and the air flows merge at the gap 4, thereby increasing the pressure at that position and exerting a force to levitate the magnetic tape from the gap. Therefore, when recording a signal on a magnetic tape or reproducing a signal from a magnetic tape, space loss increases, and the reproduction output, particularly in a short wavelength region, decreases and becomes unstable.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a magnetic head having a structure in which air pressure does not increase in the gap portion in order to eliminate increased space loss and fluctuations.

[Means for Solving the Problems] In order to achieve the above object, the magnetic head of the present invention is a magnetic head made of a combination of magnetic materials having different hardnesses. Among the magnetic materials in the magnetic material, the shape of the magnetic material with low hardness is such that when the magnetic tape runs, the area of the part that contacts the magnetic tape later than the magnetic gap part is larger than the area of the part that contacts the magnetic tape earlier. shall be.

Further, in the magnetic head of the present invention, in a magnetic head formed by combining magnetic materials with different hardnesses, the shape of the magnetic material with lower hardness among the magnetic materials on the sliding surface with the magnetic tape of the magnetic head is such that the shape of the magnetic material with lower hardness is Sometimes, the area of the part that contacts the magnetic tape later than the magnetic gap part is larger than the area of the part that contacts the magnetic tape earlier than the magnetic gap part, and there is an air escape in the part of the sliding surface that contacts the magnetic tape later than the magnetic gap part. It is characterized by a groove.

[Function] The width of the magnetic alloy part, which has a lower hardness than other parts of the magnetic head, is made wider in the part that comes into contact with the magnetic tape later than the gap part, or an air relief groove is added in the part that comes into contact with the magnetic tape later than the gap part. By providing this, the space between the magnetic tape and the magnetic head gap can be stably kept small, making it possible to record wideband signals such as high-definition signals. Furthermore, even if the head is unevenly worn, performance does not deteriorate, so the life of the head can be extended.

[Example] The present invention will be described in detail below with reference to the drawings.

Embodiment 1 An embodiment of the present invention is shown in FIGS. 1A and 1B. Figure A is a plan view of the sliding surface of the magnetic head against the magnetic tape, and Figure B is a perspective view showing the state after the magnetic tape is running. In the figure, 1 is a ferrite core, 2 is a magnetic alloy part, 3 is a glass part,
4 is a gap part. 10 is the running direction of the magnetic tape. As shown in FIG. 1A, the width of the magnetic alloy part 2, which has a lower hardness than other parts, is narrow at the part that first contacts the magnetic tape (hereinafter referred to as the tip of the magnetic head), and the magnetic The part that comes into contact with the tape (hereinafter referred to as the rear end of the magnetic head) is wide. When a magnetic tape is run for a long time on a magnetic head with such a configuration, the magnetic alloy portion 2 wears out, and a recess is formed that gets wider toward the rear end of the magnetic head, as shown in FIG. 1B. Ru. As a result, by gradually increasing the volume of the air pocket, the pressure increase at the gap part is alleviated, and by increasing the area of the alloy part on the side that comes into contact with the tape later, negative pressure is generated. Tape can be sucked into the gap. Therefore, space loss during recording and reproduction can be reduced, and recording and reproduction can be performed stably.

Embodiment 2 FIG. 2 shows another embodiment of the present invention. The figure is a plan view showing the sliding surface of the magnetic head and the magnetic tape. Note that FIGS. 3 to 7, which will be described later, are all plan views showing the same portion of the magnetic head.

In this embodiment, the width of the magnetic alloy portion 2 that comes into contact with the tape after a delay is increased by providing a step 12 at the gap portion 4, and when a recess is formed due to wear, negative pressure is generated at this step. Gap part 4
It is designed to attract magnetic tape.

Example 3 FIG. 3 shows another embodiment of the invention.

In this embodiment, the width of the magnetic alloy portion 2 is made wider at the rear end than at the front end of the magnetic head, and the magnetic alloy portion 2 is exposed at the side edges of the magnetic head. When the magnetic alloy is worn out, air is allowed to escape to the side surface of the magnetic head, and the starting point of the boundary line 8, which comes into contact later, is an extension of the boundary line 9, which comes into contact first.
Alternatively, it is provided at a later position to improve air discharge and create negative pressure in the gap portion 4 to attract the magnetic tape.

Example 4 FIG. 4 shows another embodiment of the invention.

In this embodiment, the width of the magnetic alloy part 2 is made wider at the rear end of the magnetic head, and the side surfaces of the magnetic head are formed obliquely so that air from the rear part of the gap part 4 can be easily discharged. creates negative pressure.

Example 5 FIG. 5 shows another embodiment of the invention.

In this embodiment, the width of the magnetic alloy part 2 is made wider at the rear end of the magnetic head, and the side surfaces of the magnetic head are made obliquely to divert the air flow to the sides, and the trapped air is transferred to the air reservoir. Negative pressure is generated by adopting a structure that rapidly expands the area.

The magnetic heads constructed as in Examples 2 to 5 all attract magnetic tape to the gap portion 4 in the same way as the magnetic head in Example 1, and are capable of recording and reproducing stably and with small space loss. .

Example 6 FIG. 6 shows still another embodiment of the present invention.

In this embodiment, an air escape groove 13 is provided at the rear end of the magnetic alloy section 2, which is wider at the rear end of the magnetic tape than at the front end, and is closer to the rear end than the gap 4 of the magnetic alloy section 2. In this example, the grooves 13 are provided at both the boundary between the magnetic alloy portion 2 and the ferrite core 1 and the boundary between the glass portion 3, but they may be provided only at one of the boundaries. By providing the air escape groove 13 in this way, negative pressure is generated in the gap 4, which attracts the magnetic tape, allowing stable and low-loss recording and recording.
Can be played.

Example 7 FIG. 7 shows still another embodiment of the present invention.

In this embodiment, the air escape groove 13 is provided in the ferrite portion 1 closer to the rear end of the magnetic head than the gap portion 4. Others are the same as Example 6,
The effect is also similar to that of the magnetic head of Example 6.

[Effects of the Invention] As explained above, the width of the magnetic alloy part, which has a lower hardness than other parts of the magnetic head, is made wider at the part that comes into contact with the magnetic tape later than the gap part, or the width is made wider in the part that comes into contact with the magnetic tape later than the gap part. By further providing an air escape groove in the area where the head gap is located, the space between the magnetic tape and the magnetic head gap can be stably kept small, making it possible to record broadband signals such as high-definition signals. Furthermore, even if the head is unevenly worn, performance does not deteriorate, so the life of the head can be extended.

[Brief explanation of the drawing]

FIGS. 1A and 1B show embodiments of the present invention, and FIGS.
1 is a plan view of the sliding surface of the magnetic head, FIG. B is a perspective view showing the condition of the sliding surface after the magnetic tape runs, and FIGS. 8 is a perspective view of a conventional magnetic head.
FIGS. 9A and 9B are a plan view of the sliding surface of a conventional magnetic head and a perspective view showing the state after running the magnetic tape, respectively. 1... Ferrite core, 2... Magnetic alloy part,
3... Glass portion, 4... Gap portion, 6... Winding window, 10... Magnetic tape running direction, 12... Step, 13... Air relief groove.

Claims (1)

[Scope of Claims] 1. In a magnetic head formed by combining magnetic materials with different hardnesses, the shape of the magnetic material with lower hardness among the magnetic materials on the sliding surface of the magnetic head with the magnetic tape is similar to that of the magnetic tape. A magnetic head characterized in that the area of a portion that contacts the magnetic tape later than the magnetic gap portion during running is larger than the area of the portion that contacts the magnetic tape earlier. 2. In a magnetic head formed by combining magnetic materials with different hardnesses, the shape of the magnetic material with lower hardness among the magnetic materials on the sliding surface of the magnetic head with the magnetic tape is such that when the magnetic tape runs, the magnetic material has a lower hardness than the magnetic gap portion. The area of the portion that contacts the magnetic tape later is larger than the area of the portion that contacts the magnetic tape earlier, and an air relief groove is provided in the portion of the sliding surface that contacts the magnetic tape later than the magnetic gap portion. A magnetic head characterized by: