JPH0245241B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a rotating magnetic head suitable for use in a small video tape recorder.

Generally, a video tape recorder runs a magnetic tape diagonally around the circumference of a cylinder, and
A magnetic head rotating on the cylinder surface is brought into sliding contact with the magnetic tape to record and reproduce signals. In recent years, there has been a strong demand for so-called helical scanning VTRs to be smaller and lighter and to have longer recording times.
For example, it is hoped that a compact and lightweight VTR with a recording time of 10 hours or more and weighing only a few kilograms will emerge, and this will require the development of a compact and highly accurate rotating magnetic head.

Conventionally, a rotating magnetic head used in a VTR has a rotating shaft 1, as shown in FIGS. 1a to 1c, for example.
A head base 3a, facing 180 degrees, is mounted on a rotary plate 2 which is mounted on a rotary plate 2 and rotates integrally with the rotary shaft 1.
It has a structure in which single magnetic heads 4a and 4b are attached via 3b. The single magnetic heads 4a and 4b are
As shown schematically and enlarged in FIG.
It has a structure in which the core bodies 5a and 5b face each other with a winding 6 at their tips, and a magnetic path is formed in the core bodies 5a and 5b to record signals on a magnetic tape that slides on the tips of the core bodies. It performs regeneration. After the single magnetic heads 4a and 4b are fixed to the head bases 3a and 3b, they are fixed to the rotary plate 2.
The gap G is mounted on the top at a position facing 180 degrees diametrically (within an error of 1'), with its tip positioned as accurately as possible so that it is equidistant from the center of rotation. At this time, the height of the head (track center position) relative to the magnetic tape is also adjusted with high precision before installation.

However, assembly (manufacturing) of a rotating magnetic head that requires highly accurate positioning and adjustment not only requires highly accurate assembly jigs and microscope equipment, but also requires highly skilled assembly techniques. Requires. Moreover, when trying to miniaturize the head in accordance with the above requirements, not only the size of each component becomes a problem, but also the manufacturing of the head becomes extremely difficult due to the limitations of the jig and other problems. There was a problem that made it difficult. In particular, it has been almost impossible to realize the specification that the rotational diameter of the head is about 5 cm with the above-mentioned conventional structure.

Furthermore, as the rotating diameter becomes smaller, the width of the magnetic tape becomes relatively larger when viewed from the rotating head, so it is necessary to consider the effect of contact with the tape.

The present invention was made in view of these circumstances, and is suitable for being incorporated into a small VTR.
An object of the present invention is to provide a rotating magnetic head which is small in size, easy to assemble with high precision, and has an excellent contact effect with a magnetic tape surface.

Embodiments of the present invention will be described below with reference to the drawings.

FIGS. 2 and 3 show a rotating magnetic head which is the premise of this invention, and the features of this invention are specifically shown in FIGS. 4 to 6.

The semicircular first and second core halves 11 and 12 made of magnetic plates form a pair with the semicircular linear portions serving as the chords as abutting surfaces, and are separated by a predetermined gap G. They are butted together and integrated. This bonding is performed using, for example, a glass-based adhesive, and the gap G is regulated to a size that forms a head gap of the head portion, which will be described later. Therefore, winding grooves 13 and 14 are provided at a predetermined depth from both ends at positions at both ends of the abutting surfaces of the first and second core halves 11 and 12, respectively. . Also, the first core half 1
Winding grooves 15 are provided at both ends of the abutting surface of 1, slightly penetrating from both end edges thereof. Winding wires 16 and 17 are respectively wound on both ends of the first and second core halves 11 and 12 through these winding grooves 13, 14 and 15, and the two magnetic head portions facing each other at an angle of 180° are formed. It is formed. These magnetic head portions are joined with the above-mentioned predetermined gap G, and magnetic paths are provided at both ends in the direction of the joining surface of a disk body consisting of the integrated first and second core halves 11 and 12. The end face of the magnetic tape is used as a head face for recording and reproducing signals on a magnetic tape that slides into contact with the head face. Each of the windings 16 and 17 of these magnetic head portions is connected to the core half 1.
The terminals 1 and 12 are guided and connected to lead terminals 18 and 19 provided on the terminals 1 and 12, respectively. This lead terminal 1
Signal transmission and reception between 8 and 19 and the external recovery is performed via a rotating transformer (not shown) or the like.

On the other hand, the first and second core halves 11,1
The rotation center axis 2 is located at a position equidistant (Q _a = Q _b ) from the head surfaces of both ends of the abutting joint surfaces of the two.
A rotation center position regulating groove 21 is provided which abuts on the rotation center position and regulates the rotation center position. This position regulating groove 21 is comprised of a triangular groove 22 provided in the first core half body 11 and a triangular groove 22 provided in the second core half body 12 through which the rotating shaft 20 is inserted and which ensures clearance. It consists of a circular groove 23. The groove 22 is
A rotating shaft 20 that abuts on the triangular shape with its two equiangular sides, the center of which is located at the center of the joint surface,
Further, the distances Q _a and Q _b from the head surface are restricted to be equal. The rotating magnetic head, which is composed of the joined body of the first and second core halves 11 and 12 whose position is regulated with respect to the rotating shaft 20 by the position regulating groove 21, is connected to the rotating shaft 20.
It is rotated integrally with the

Note that the head surface is defined by (D _a =
Of course, the dimensions are controlled to ensure a predetermined amount of protrusion D _b ).

Thus, in a rotating magnetic head having such a structure, the rotating plate itself functions as the core of the head,
Two magnetic head portions are formed at both ends of the joint surface, facing exactly 180 degrees. Furthermore, these two magnetic head sections function as magnetic heads by forming independent magnetic paths at both ends of the joint surfaces (butting surfaces) on the rotary plate consisting of the core halves 11 and 12, respectively. Become. Furthermore, the center of rotation of the rotating plate (joint body of the core halves 11 and 12) is accurately positioned by the position regulating groove 21 at a position equidistant from the head surface and passing over the center (diameter) thereof. That will happen. Therefore, the dimensional accuracy can be made very high. In addition, in a rotating magnetic head having such a structure, since the rotating plate and the magnetic head part are integrally constructed, the dimensions and position can be determined with high precision simply by adjusting the size and position with respect to the core halves 11 and 12. , no special jigs or microscope equipment are required. Furthermore, since the manufacturing process can be easily and accurately managed, a rotating magnetic head with desired specifications can be realized extremely easily. At the same time,
Since it has an integral structure as described above, it is very easy to reduce its size. In particular, the advantage of being able to accurately form two magnetic head sections at positions equidistant from the center of rotation and facing each other at 180 degrees is enormous.

Therefore, with such a head structure, it is extremely easy to incorporate it into a cylinder.
When installing the head, the center position is regulated by the groove 20, which has the effect of greatly simplifying maintenance including head replacement work.

In the above description, the core halves 11 and 12 are described as being semicircular, but as shown in FIG. It is also possible to control the center position in the same way as described above even if the head surface is processed.

4 and 5 show the specific shape of the rotating magnetic head of the present invention.

In other words, it is a rotating magnetic head having a structure based on a spindle-shaped rotating plate (core) in which parts of elliptical or circular arcs abut each other. In this shape as well, the dimensions are controlled so that the head surface protrudes from the cylinder surface indicated by the two-dot chain line by a predetermined amount, and the dimensions are determined so that other parts do not touch the cylinder surface. With this shape, the magnetic head is formed at both ends of the long axis of the rotating body formed by the first and second core halves, so the contact effect between the tape surface and the magnetic head during recording and reproduction is significantly improved. Excellent.

Further, the position regulating groove 21 may also have the shape shown in FIGS. 4 and 5. That is, as shown in FIG. 4, the tip of the rotating shaft 20 is shaped like a quarter circle, and the position regulating groove 21 is shaped like a quarter circle, and the groove side 26 is provided in the first core half body 11; Second
The position may be restricted by the side 27 of the core half 12. In this case, the dimensions of the groove sides 26 may be regulated so that they are equidistant from the head surface. Further, as shown in FIG. 5, the position regulating groove 21 is provided in a rectangular shape, and its sides 28, 2
The rotation center position is regulated by 9, and the auxiliary groove 3 is pressed by inserting a pin 30.
1a and 31b may be provided, and a structure may be adopted in which they cooperate to regulate the position. It goes without saying that various kinds of position regulating grooves can be employed as appropriate.

By the way, the head track width T _w at each magnetic head portion of a rotating magnetic head having such a structure is:
For example, the following regulations apply: In the structure shown in FIGS. 2a and 2b, the first and second core halves 11 and 12 are made by cutting out a magnetic plate having a thickness of t. Therefore, in the case of such first and second core halves 11 and 12, the peripheral edge of one side thereof is formed into a tapered shape, and the thickness of the tip (peripheral edge) is T _w
By doing this, the track width can be
T _w can be regulated easily and with high precision.
However, when the tapered head is used as described above, the tip of the head becomes sharp and may damage the tape surface.

Therefore, in the rotating magnetic head of the present invention, the structure shown in FIG. 6 is adopted to construct the magnetic head section.

That is, the ends of the first and second core halves 11 and 12, that is, the position where the head surfaces are formed, are filled with a non-magnetic material having good wear resistance, such as glass, from both plate surfaces, as shown by diagonal lines in the figure. Cutouts 32 and 33 are provided, and these cutouts 32 and 33 regulate the track width _Tw . In this case, notch 3
Of course, by varying the heights of 2 and 33, the above-mentioned track T _w can be arbitrarily set.
It is also possible to arbitrarily set the head height H, that is, the track position.

In this way, the contact surface of the tip of the magnetic head with the tape surface can maintain the thickness of the core half, and will not damage the tape surface unlike a sharp tip.

As described above, according to the head structure according to the present invention, the dimensions and positions of each part of the head can be easily regulated with high precision, and it is also very easy to reduce the size and weight. In addition, it has tremendous effects that cannot be expected from conventional structures, such as the fact that the work of attaching the head to the device (cylinder mechanism) is extremely simple.

Next, a method of manufacturing a rotating magnetic head according to the present invention will be explained with reference to FIGS. 7a and 7b.

First, prepare a magnetic block that will become the core. Then, this block body is processed into a cylinder shape, and this is equally divided along a plane passing through the central axis to form two semi-cylindrical blocks 41 and 42. Among these, winding grooves 43, 44 and a triangular position regulating groove 45 are bored in the divided surface of the semi-cylindrical block 41, as shown in FIG. 7a. The winding grooves 43 and 44 are provided on both sides of the split surface, and the position regulating groove 45 is provided at a position passing through the center of the split surface, that is, at a position equidistant from the edge of the split surface. . The other semi-cylindrical block 42 is provided with a semi-circular groove 46 opposite to the position regulating groove 45.

Thereafter, the two semi-cylindrical blocks 41 and 42 are butted and joined with a predetermined gap G using an organic adhesive or glass. This state is shown in FIG. 7b. After that, the above block 41,
A winding groove 47 is bored in the circumferential surface of the blocks 41 and 42 along the joint surface of the block 42, and then this block body is cut out to a thickness t. Then, this cut out plate 48
_Taper the peripheral edge of one side of the
At the same time, the dimensions are adjusted so that the distance between the head surface and the position regulating groove is equal. Of course, it goes without saying that the above distance also matches the head specifications. Thereafter, a winding is applied to the end of the joint surface of the plate 48 through the grooves 43, 44, 47, and the rotating magnetic head according to the present invention is completed as a magnetic head section.

In this way, the present rotating magnetic head can be manufactured very simply and with highly accurate size and position control, and can also be manufactured by cutting out from a single block, making it highly suitable for mass production. Furthermore, since the dimensions can be controlled in the form of a block, it is easy to handle during production, and even if miniaturization is attempted, there is no risk of hindering production.

Note that the present invention is not limited to the above embodiments. For example, as shown in FIG. 5, the core half 11,
A separation band 49 made of a non-magnetic material such as glass, ceramic, or metal is provided in the center of the core halves 11 and 12 to separate the magnetic paths of the magnetic heads formed at both ends of the core halves 11 and 12, and to prevent a cross between them. It may also have a structure that prevents talk. Furthermore, it is of course possible to provide the winding groove 15 on the second core half 12 side. Furthermore, the gap G may be determined according to the head specifications, and glass welding or other means can be applied to join the core halves. In short, the present invention can be implemented with various modifications without departing from the gist thereof.

[Brief explanation of the drawing]

1A to 1C are diagrams showing an example of a rotating magnetic head with a conventional structure, FIGS. 2A and 2B are configuration diagrams of a rotating magnetic head showing an embodiment of the present invention, and FIGS. 3 to 5 are respectively A configuration diagram of a rotating magnetic head showing another embodiment of the present invention, FIG. 6 is a diagram showing an example of a track width regulating means, and FIGS. 7 a and b are an example of a method for manufacturing a rotating magnetic head according to the present invention. FIG. 11, 12... Core half, 13, 14, 15...
... Winding groove, 16, 17... Winding wire, 18, 19...
Lead terminal, 20... Rotating shaft, 21, 22, 23
... Rotation center position regulation groove, 24, 25 ... Core half, 26, 27 ... Side, 30 ... Pin, 31a,
31b...auxiliary groove, 32, 33...notch.

Claims (1)

[Claims] 1. The linear portions of the first and second core halves made of magnetic material are butted and joined with a predetermined gap,
In a rotating magnetic head that forms two magnetic head portions facing each other at 180 degrees, forming a magnetic path with both ends of the abutting surfaces as head surfaces, the shape formed by the first and second core halves is formed by the abutting surface. The structure of the magnetic head part maintains the thickness of the core half, and the gap length is filled with non-magnetic material from both sides in the thickness direction to regulate the track width. A rotating magnetic head characterized by having a structure in which: