JP2525863B2 - Rotating head device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a rotary head device used in a helical scan type magnetic recording / reproducing apparatus, and in particular, a plurality of magnetic heads having a predetermined step are attached. Rotary head device.

[Conventional technology]

In recent years, video tape recorders have become more multifunctional and improved in performance, and along with this, the number of magnetic heads provided in the rotary head device has also increased. For example, magnetic heads dedicated to standard recording / reproducing mode and long-time recording / reproducing mode are used respectively, and magnetic heads dedicated to special reproduction such as still and slow reproduction are also used. Also, erasing called flying erase head is used. Heads and recording / reproducing heads for FM audio signals are also being provided in rotary head devices.

By the way, when attaching such a magnetic head to a rotary cylinder of a rotary head device, it is necessary to provide a step in the rotational axis direction of the rotary cylinder between the magnetic heads having different functions and applications. For example, in the case of the fly glaze head, scanning is performed on the locus of the recording / reproducing magnetic head of the video signal,
The track on the magnetic tape must be able to be erased at every rotation, but for this purpose, it must be arranged on the rotating cylinder with a predetermined step with respect to the recording / reproducing magnetic head.

Conventionally, in a rotary head device, the height of the magnetic head can be adjusted by attaching a head base with a magnetic head mounted on the base mounting surface of the rotary cylinder and bending the head base with an adjusting screw. , This makes the height of each magnetic head different,
A predetermined step is provided between them. However, in this method, the magnetic head is rotated around the attachment point of the head base to the rotary cylinder by the operation of the adjusting screw, and the height of the magnetic head is adjusted by this, so that the magnetic head is adjusted. The head-based magnetic head that has been largely deflected to obtain a step between the heads will contact the magnetic tape at an angle, and the reproduction output of this magnetic head will drop significantly due to space loss. become.

Therefore, conventionally, as another method for obtaining a step between the magnetic heads, as shown in FIG. 7, a head base 4 provided with a magnetic head 2 is sandwiched by a spacer 13 having a thickness corresponding to the step. A method is known in which the screw 6 is attached to the rotary cylinder 1. According to this method, a predetermined step between the magnetic heads is almost obtained by the spacer 13, and a slight adjustment by the adjusting screw causes an error in the step due to an error in the thickness of the spacer 13 or the width of the magnetic head 2. Since the correction can be performed, the predetermined step between the magnetic heads can be accurately set without causing the head base to be largely bent.

However, according to this method, a spacer is required to set the steps of the magnetic head, which increases the number of parts and leads to cost increase.

Japanese Patent Laid-Open No. 59-16 proposed to solve this problem.
In the rotary head device described in No. 5233, two through holes penetrating from one side surface to the other side surface and these through holes are provided between the mounting portion of the head base on the rotating cylinder and the mounting portion of the magnetic head. A slit is provided so as to be connected to and penetrate between the side surfaces, and only the portion between the through holes of the head base is bent by the adjusting screw. According to this rotary head device, even when the head base is bent by the adjusting screw, the head mounting surface near the magnetic head of the head base moves up and down while being parallel to the base mounting surface of the rotating cylinder, and thus the magnetic tape. While maintaining a good contact state of the magnetic head with the magnetic head, the step between the magnetic heads can be set to a predetermined level.

Further, as another method of obtaining the step difference between the magnetic heads, there is a method of milling the surface of the rotary cylinder and providing a mounting surface for each head base. Each head mounting surface is provided with a height difference according to the step difference between the magnetic heads of the head base mounted on the head mounting surface.

[Problems to be Solved by the Invention]

By the way, in the rotary head device disclosed in the above-mentioned JP-A-59-165233, the head base has, in addition to forming processing of the outer shape and finishing processing such as a head mounting surface,
Through holes and slits need to be processed, resulting in cost up, and further miniaturization of video tape,
Due to the demand for thinning, the rotary head device also needs to be downsized and thinned. For this reason, the head base also needs to be downsized and thinned by narrowing the space required for it. According to this, it is very difficult to form the through hole and the slit, and the cost is further increased.

Further, the above method of forming the mounting surface of each head base on the rotary cylinder has a problem in that the processing is complicated and laborious, which increases the processing cost and the assembly cost.

An object of the present invention is to solve the above problems, and to provide an inexpensive rotary head device that can easily and arbitrarily set the step between magnetic heads with high accuracy.

[Means for solving the problem]

In order to achieve the above object, according to the present invention, a plurality of mounting surfaces are provided on a lower surface side of a rotating cylinder in a concentric circle with a predetermined step around the rotation axis, and a magnetic head is attached to each of the mounting surfaces. Attach the head base.

[Action]

The step difference between the mounting surfaces is set to a necessary step difference between the magnetic heads of the head base mounted on these mounting surfaces. Therefore, there is no step between the magnetic heads of the head base which are attached to the same mounting surface, but a predetermined step is obtained between the magnetic heads which are attached to different mounting surfaces.

These mounting surfaces are the surfaces of the rotary cylinder and can be formed as part of the machining of the rotary cylinder. That is, since the mounting surface is concentrically provided on the lower surface side of the rotary cylinder about its rotation axis, the mounting surface can be adjusted by simply adjusting the cutting amount of the cutting tool during external turning of the rotary cylinder. By providing a predetermined step between them, it is possible to process easily and accurately.

〔Example〕

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

FIG. 1 is a plan view showing an embodiment of a rotary head device according to the present invention, in which 1 is a rotary cylinder, 2a to 2d, 3 are magnetic heads, 4a to 4d, 5 are head bases, 6a to 6d, 7a, 7b is a screw,
8 and 9 are mounting surfaces.

In FIG. 1, five magnetic heads 2a to 2d, 3 are mounted on the rotary cylinder 1, and the magnetic head 2a
˜2d are arranged at the same height with respect to the surface of the rotary cylinder 1, and there is a step (height deviation) between these magnetic heads 3 and 2.

The magnetic heads 2a to 2d are attached to the head mounting surfaces of the head bases 4a to 4d, respectively.
The magnetic heads 4a to 4d are fixed to the rotary cylinder 1 by screws 6a to 6d such that the magnetic heads 2a to 2d are arranged at an angular interval of 90 °. The magnetic head 3 is attached to the head mounting surface of the head base 5, and is fixed to the rotary cylinder 1 by screws 7a and 7b so that the magnetic head 3 is located in the middle of the magnetic heads 2a and 2d.

As shown in FIG. 2, the rotating cylinder 1 is provided with two mounting surfaces 8 and 9 concentrically around the rotation axis of the rotating cylinder 1 with a predetermined step. 9 is protruding.

In this embodiment, a smaller-diameter cylinder is used than the conventional stationary type video tape recorder, and a magnetic tape (not shown) runs obliquely over the outer circumference of the small-diameter cylinder over 270 ° or more. In the rotary head device of such a small diameter cylinder, in FIG. 1, the magnetic heads 2a to 2d are recording / reproducing heads, and the magnetic head 3 is a flying erase head. The magnetic heads 2a to 2d record or reproduce signals by rotating the magnetic tape in steps of 270 °. The flying erase head also erases the tracks on the magnetic tape by every 270 ° rotation that scans the magnetic tape. Signals are recorded on the erased portions by the magnetic heads 2a to 2d. And like this,
In order to relate the scanning loci of the magnetic heads 2a to 2d and the magnetic head 3, it is necessary to provide them with a predetermined step.

In FIG. 1, the magnetic head 3 is the magnetic head 2a, 2d.
However, the present invention is not limited to this, and can be provided at an arbitrary position by appropriately setting the steps of the mounting surfaces 8 and 9.

Therefore, in FIG. 1, the head bases 4a to 4d are mounted on the mounting surface 8, while the head base 5 is mounted on the mounting surface 9. Let r _{1 be} the radius of the mounting surface 8 and r ₂ be the distance from the center of the rotary cylinder 1 to reach the head base 5, so that r ₁ <r ₂ and the head base 5 can be mounted on the mounting surface 9. ing.

Needless to say, when the head bases 4a to 4d, 5 are attached to the rotary cylinder 1 as described above, the magnetic heads 2a to 2d, 3 slightly project from the outer circumference of the rotary cylinder 1.

FIG. 3 is a sectional view taken along the section line XX in FIG. 1, and FIG. 4 is a sectional view taken along the section line YY.

As is clear from these drawings, the head base 4a is attached to the rotary cylinder 1 so that its head mounting surface abuts the mounting surface 8 (the same applies to the head bases 4b to 4d), and the head base 5 also has its head mounting surface mounted on the mounting surface 9. Is attached to the rotary cylinder 1 so as to abut. Therefore, the level difference between the magnetic heads 2a and 3 is determined by the level difference D between the mounting surfaces 8 and 9 and the width of the magnetic heads 2a and 3, and is not affected by the thickness of the head bases 4a and 5.

Therefore, as shown in FIG. 5, the height of the center of the track width of the magnetic head 2a from the head mounting surface 10a of the head base 4a is H ₁ , and the track width of the magnetic head 3 from the head mounting surface 11 of the head base 5 is When the height of the center is H ₂ , the step H of the magnetic heads 2a, 3 is H = D + H ₂ −H ₁ . Therefore, as shown in Fig. 6, the magnetic head
The magnetic head 2a and the magnetic head 3 are attached to the rotary cylinder 1 with a step H expressed by the above equation.
When the heights H ₁ and H ₂ are determined, the step D between the magnetic heads 2a to 2d and the magnetic head 3 can be set as desired by appropriately setting the step D on the mounting surfaces 8 and 9. In FIG. 6, 12 is a fixed cylinder.

The steps between the magnetic heads 2a to 2d and the magnetic head 3 are set as described above. However, in order to set the height of each magnetic head more accurately, or in addition, the dimensional error of each magnetic head or In order to more accurately set the step H between the magnetic heads 2a to 2d and the magnetic head 3 depending on the accuracy of the step D on the mounting surfaces 8 and 9, the head bases 4a to 4d are adjusted by adjusting screws (not shown) as in the prior art. , 5 can be adjusted respectively.

In this embodiment, the mounting surfaces 8 and 9 are concentrically provided on the lower surface side of the rotary cylinder 1 about the rotation axis thereof.
It can be easily formed as a part of the turning process of the rotary cylinder 1, and the special process for providing a step between the magnetic heads and the parts and the assembly process thereof are not necessary, and the increase in cost up can be suppressed. Moreover, the required step D of the mounting surfaces 8 and 9 can be set with high accuracy only by adjusting the cutting amount of the cutting tool in the turning process.

The mounting surfaces 8 and 9 do not have to be continuous over the entire circumference, and it is sufficient that the mounting surfaces of the respective head bases have a sufficient area for mounting them.

In the above embodiment, as the rotary head device for the small diameter cylinder, two mounting surfaces 8 are provided, and four mounting heads are mounted on the mounting surface 8 and one mounting head is mounted on the mounting surface 9, respectively. The present invention is not limited to this, and may be a rotary head device such as a stationary video tape recorder, and three or more mounting surfaces may be provided, and one or more head bases may be attached to each.

〔The invention's effect〕

As described above, according to the present invention, a plurality of mounting surfaces are provided on the lower surface side of the rotary cylinder in a concentric pattern with a predetermined step around the rotation axis, and magnetic heads are attached to each of the mounting surfaces. Since the head base is attached, the rotary cylinder can process the mounting surface as part of its turning process, and the step of each magnetic head can be set arbitrarily and with high accuracy without increasing the number of parts and assembly processes. The effect is obtained.

[Brief description of drawings]

1 is a plan view showing an embodiment of the rotary head device according to the present invention, FIG. 2 is a plan view showing the rotary cylinder in FIG. 1, and FIG. 3 is a cross section taken along the line XX in FIG. Figure,
FIG. 4 is a sectional view taken along the section line Y--Y, FIG. 5 is an explanatory view of a step between the magnetic heads of this embodiment, and FIG. 6 is a magnetic head mounted with the step of this embodiment. FIG. 7 is a partial front view showing a portion, and FIG. 7 is a partial sectional view showing an example of attachment of a magnetic head in a conventional rotary head device. 1 ... Rotary cylinder, 2a-2d, 3 ... Magnetic head, 4a-4
d, 5 …… Head base, 8,9 …… Mounting surface.

Claims (1)

(57) [Claims] 1. A rotary head device having a rotary cylinder having a mounting surface for mounting a head base on which a magnetic head is mounted, wherein a plurality of the mounting surfaces are provided on the lower surface side of the rotary cylinder with the rotary shaft of the rotary cylinder as the center. A rotary head device, wherein the rotary head device is arranged concentrically and a step is provided in the direction of the rotation axis.